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Sample records for diamante cvd em

  1. Geologia e Mineralogia do Diamante da Serra do Espinhaço em Minas Gerais

    OpenAIRE

    Mario Luiz de Sá Carneiro Chaves

    1997-01-01

    A Serra do Espinhaço é conhecida como a região mais clássica em termos de produção de diamantes no Brasil, embora seja atualmente responsável por somente 20% dessa produção. O Supergrupo Espinhaço, de idade mesoproterozóica, é a seqüência geológica que sustenta a serra, e na qual ocorrem intercalados em sua porção basal conglomerados diamantíferos (o \\"Conglomerado Sopa\\", da Formação Sopa Brumadinho) que constituem a virtual fonte espalhadora do mineral na região. Para o conhecimento da geol...

  2. Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry; Proprietes thermoluminescentes du diamant CVD: applications a la dosimetrie des rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Petitfils, A

    2007-09-15

    Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

  3. Avaliação do tipo de diamante de benzel em pacientes portadores de mielopatia cervical Evaluación del tipo de diamante de benzel en pacientes con mielopatia cervical Evaluation of the type of benzel's diamond in patients with cervical myelopathy

    Directory of Open Access Journals (Sweden)

    Rodrigo Rezende

    2012-12-01

    Full Text Available OBJETIVO: Difundir o método de Benzel para aferição da angulação cervical e quantificar a prevalência de cada tipo de diamante de Benzel em 30 pacientes portadores de mielopatia cervical com indicação cirúrgica. MÉTODOS: Estudo retrospectivo de pacientes portadores de mielopatia cervical submetidos a tratamento cirúrgico. Foram analisadas radiografias em perfil da coluna cervical onde se aferiram os tipos diamante de Benzel usando técnicas descritas pelo próprio Benzel. Excluímos do estudo aqueles pacientes que desenvolveram a doença após traumas, que foram submetidos reoperações ou aqueles que não forneceram radiografias em perfil adequadas para aferição. RESULTADOS: Foram avaliados 30 pacientes, sendo 25 deles do sexo masculino, com idade entre 30 e 74 anos (média de 52,4 anos. Após a realização das medidas foram encontrados 24 pacientes com diamantes do tipo A (80%, 2 do tipo B (6,7% e 4 tipo C (13,3%. CONCLUSÃO: O diamante de Benzel tipo "A" foi encontrado em 80% dos pacientes portadores de mielopatia cervical no período pré-operatório.OBJETIVO: Difundir el método de Benzel para la medición del ángulo cervical y cuantificar la prevalencia de cada tipo de diamante Benzel en 30 pacientes portadores de mielopatía cervical con indicación quirúrgica. MÉTODOS: Estudio retrospectivo de los pacientes con mielopatía cervical sometidos a tratamiento quirúrgico. Se analizaron las radiografías de perfil de la columna cervical, donde se midieron los tipos de diamante utilizando las técnicas descritas por el mismo Benzel. Se excluyeron del estudio los pacientes que desarrollaron la enfermedad después de trauma, que fueron sometidos a reoperaciones o los que no han presentado adecuadas radiografías de perfil para la medición. RESULTADOS: Se evaluaron 30 pacientes entre los cuales 25 eran del sexo masculino, con edades comprendidas entre 30 y 74 años (promedio de 52,4 años. Después de la realización de las

  4. Cutting characteristics of dental diamond burs made with CVD technology Características de corte de pontas odontológicas diamantadas obtidas pela tecnologia CVD

    Directory of Open Access Journals (Sweden)

    Luciana Monti Lima

    2006-04-01

    Full Text Available The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding type of substrate (enamel and dentin and direction of handpiece motion. The morphological characteristics, width and depth of the cavities were analyzed and measured using scanning electron micrographs. Statistical analysis using the Kruskal-Wallis test (p O objetivo deste estudo foi determinar a habilidade de corte das pontas de diamante obtidas pelo processo de deposição química a vapor (CVD associadas ao aparelho de ultra-som no preparo cavitário minimamente invasivo. Uma cavidade padronizada foi preparada nas faces mesial e distal de 40 terceiros molares, utilizando-se pontas de diamante CVD cilíndrica e esférica. A habilidade de corte foi comparada quanto ao tipo de substrato (esmalte e dentina e quanto à direção do movimento realizado com a ponta. As características morfológicas, a largura e profundidade das cavidades foram analisadas e medidas em microscopia eletrônica de varredura. A análise estatística pelo teste de Kruskal-Wallis (p < 0,05 revelou que a largura e profundidade das cavidades foram significativamente maiores em dentina. Cavidades mais largas foram obtidas quando se utilizou a ponta de diamante CVD cilíndrica, e mais profundas quando a ponta esférica foi empregada. A direção do movimento da ponta não influenciou o tamanho das cavidades, sendo os cortes produzidos pelas pontas de diamante CVD precisos e conservadores.

  5. Tl and OSL dosimetry of diamond films CVD pure and unpurified with boron-carbon; Dosimetria Tl y OSL de peliculas de diamante CVD puras e impurificadas con boro-carbono

    Energy Technology Data Exchange (ETDEWEB)

    Melendrez, R.; Pedroza M, M.; Chernov, V.; Ochoa N, J.D.; Bernal, R.; Barboza F, M. [CIF, UNISON, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Apdo. Postal 1626, Hermosillo, Sonora (Mexico); Goncalves, J.A.N.; Sandonato, G.M. [Laboratorio Associado de Plasma, Instituto Nacional de Pesquisas Espaciais C.P. 515- 12201 -970, Sao Jose dos Campos, SP (Brazil); Cruz Z, E. [Instituto de Ciencias Nucleares, UNAM, Apdo. Postal 70-543, 04510 Mexico D.F. (Mexico); Preciado F, S.; Cruz V, C.; Brown, F. [Departamento de Investigacion en Polimeros y Materiales de la Universidad de Sonora, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Schreck, M. [Universitaet Augsburg, Institut fuer Physik D-86135 Augsburg (Germany)

    2004-07-01

    The diamond is a material that possesses extreme physical properties, such as its hardness to the radiation, its low chemical reactivity besides its equivalence to the human tissue, which qualify him as an ideal material for radiation dosimetry. In this work, it was studied the thermal and optically stimulated response (Tl and OSL) of polycrystalline diamond films grown by the technique of CVD pure and contaminated with Boron-carbon (B/C) with the intention of characterizing their efficiency like a dosemeter for radiation in a range of 0 - 3000 Gy. For the case of the films without impurities, the Tl curve presents four main peaks, two of them in an interval of temperatures of 150-200 C and other two additional around of 250-400 C. The dependence of the response of integrated Tl and that of OSL always maintained a lineal relationship with the exhibition dose up to 100 Gy. The behavior of the films contaminated with B/C (2000 - 20000 ppm) was established through experiments that involved the signal of OSL and their relationship with the Tl response. It was found that this processes are correlated, since the electrons caught in the traps of low temperature (50 - 250 C) of the Tl they are the electrons that recombining with more probability to provide the signal of OSL. According to these results it is possible to propose the diamond films as a good candidate for dosimetry to, using the traditional technique of Tl so much as well as the but recent of OSL. (Author)

  6. Desenvolvimento de métodos eletroanalíticos empregando o eletrodo de diamante dopado com boro para a determinação simultânea de edulcorantes e corantes em produtos alimentícios

    OpenAIRE

    Patrícia Batista Deroco

    2014-01-01

    Neste trabalho, desenvolveu-se métodos eletroanalíticos para a determinação simultânea dos pares: amarelo crepúsculo (AC) e aspartame (AS), azul indigotina (AI) e vermelho 40 (V40)), bem como aspartame (AS) e acesulfame-K (AK) em produtos alimentícios utilizando-se o eletrodo de diamante dopado com boro (BDD). O par AS e AC foi determinado, sem a necessidade de separação prévia em H2SO4 0,30 mol L-1 com o eletrodo de BDD pré-tratado anodicamente e utilizando amperometria de múltiplos pulsos (...

  7. Optically stimulated luminescence and thermoluminescence in CVD diamond and dosimetric evaluation in fields of ionizing radiation; Luminiscencia opticamente estimulada y termoluminiscencia en diamante DQV y evaluacion dosimetrica en campos de radiacion ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Barboza F, M.; Chernov, V.; Pedroza M, M. [Centro de Investigaciones en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Schreck, M. [Universitat Augsburg, Institut fur Physik D-86135, Augsburg (Germany); Preciado F, S.; Melendrez, R. [Universidad de Sonora, A.P. 130, 83000 Hermosillo, Sonora (Mexico)

    2006-07-01

    The optically stimulated luminescence (OSL) results a highly appropriate dosimetric technique for readings of absorbed radiation 'in alive' and 'in situ', as well as in real time. The CVD diamond on the other hand presents excellent qualities like radiation reader thanks to its reproducibility, radiation resistance, biocompatibility and non toxicity. The present work studies the answer of two diamond films pure and polluted with nitrogen (750 ppm) grown by the Chemical Vapor Deposition method (CVD) on silicon substrate (001) irradiated with beta (Sr-90) in the 0.833-100 Gy interval. The optical stimulation was carried out by 40 seconds with infrared laser (830 nm, 0.36 W/cm{sup 2}) and the filter BG-39 (300-600 nm) coupled the PM. The intensity and the decay of the hyperbolic type of the LOE curves were similar in both samples, for the non doped diamond were observed trapping states in 200-380 C being compared with those that it presents the polluted diamond with nitrogen in 80-277 C. The dosimetric behavior in the pure sample is observed lineal in two regions 0-16 Gy and in 30-100 Gy, only the doped sample didn't present linearity in the all range of the studied dose. The advantage is stood out of LOE on TL because the first one not requires of thermal stimulation in such a way that is more appropriate to detect and to measure radiation doses in biomedicine. (Author)

  8. Tribosystems based on multilayered micro/nanocrystalline CVD diamond coatings =

    Science.gov (United States)

    Shabani, Mohammadmehdi

    A combinacao das caracteristicas do diamante microcristalino (MCD) e nanocristalino (NCD), tais como elevada adesao do MCD e a baixa rugosidade superficial e baixo coeficiente de atrito do NCD, e ideal para aplicacoes tribologicas exigentes. Deste modo, o presente trabalho centrou-se no desenvolvimento de revestimentos em multicamada MCD/NCD. Filmes com dez camadas foram depositados em amostras de cerâmicos de Si3N4 pela tecnica de deposicao quimica em fase vapor assistida por filamento quente (HFCVD). A microestrutura, qualidade do diamante e adesao foram investigadas usando tecnicas como SEM, AFM, espectroscopia Raman, DRX, indentacao Brale e perfilometria otica 3D. Diversas geometrias para aplicacoes distintas foram revestidas: discos e esferas para testes tribologicos a escala laboratorial, e para testes em servico, aneis de empanques mecânicos e pastilhas de corte para torneamento. Nos ensaios tribologicos esfera-sobre-plano em movimento reciproco, sob 10-90% de humidade relativa (RH), os valores medios dos coeficientes de atrito maximo e em estado estacionario sao de 0,32 e 0,09, respetivamente. Em relacao aos coeficientes de desgaste, observou-se um valor minimo de cerca de 5,2x10-8 mm3N-1m-1 para valores intermedios de 20-25% de RH. A humidade relativa tem um forte efeito sobre o valor da carga critica que triplica a partir de 40 N a 10% RH para 120 N a 90% de RH. No intervalo de temperaturas 50-100 °C, as cargas criticas sao semelhantes as obtidas em condicoes de baixa RH ( 10-25%). A vida util das ferramentas com revestimento de dez camadas alternadas MCD/NCD e 24 mum de espessura total no torneamento de um composito de matriz metalica Al- 15 vol% Al2O3 (Al-MMC) e melhor do que a maioria das ferramentas de diamante CVD encontradas na literatura, e semelhante a maioria das ferramentas de diamante policristalino (PCD). A formacao de cratera ocorre por desgaste sucessivo das varias camadas, atrasando a delaminacao total do revestimento de diamante do

  9. Caracterização dosimétrica de feixes de fótons com detector de diamante

    Directory of Open Access Journals (Sweden)

    Talita Sabino

    2012-02-01

    Full Text Available OBJETIVO: Este trabalho foi realizado com o objetivo de caracterizar o detector de diamante, bem como observar seu comportamento. MATERIAIS E MÉTODOS: As características dosimétricas de feixes de fótons de 6 MV de energia foram medidas utilizando o sistema automático de varredura MP3 da PTW com um detector de diamante e foram comparadas com medidas usando uma câmara de ionização 31010 da PTW. RESULTADOS: As características dosimétricas do detector de diamante foram observadas por meio de medidas de linearidade com a dose, dependência com a taxa de dose e distribuições de dose em profundidade, bem como perfis. CONCLUSÃO: Algumas medidas com diamante e câmara de ionização foram validadas com resultados publicados na literatura, o que demonstrou um bom comportamento do detector de diamante na comparação com a câmara de ionização, muito utilizada para dosimetria em radioterapia, evidenciando que o diamante é uma boa escolha de detector para dosimetria de campos pequenos.

  10. Determinação de parabenos em antitranspirantes empregando voltametria sob eletrodo de diamante e cromatografia liquida de alta eficiencia

    OpenAIRE

    Francieli Cristiani Carreira

    2008-01-01

    Resumo: Ésteres do ácido p?hidróxibenzóico, tais como metilparabeno (MePa), etilparabeno (EtPa) e propilparabeno (PrPa) são conservantes químicos amplamente empregados em cosméticos, fármacos e alimentos. Uma vez que estes compostos estão associados a alergias, dermatites e propriedades estrogênicas, faz-se necessário avaliar a concentração destas substâncias nas diferentes matrizes. A ANVISA estabelece para cosméticos uma concentração máxima de parabenos totais de 0,8 % m/m. Os objetivos des...

  11. From Cape to Hortobagy: the marriage of DIAMANT with AFRODITE

    International Nuclear Information System (INIS)

    Mullins, S M; Bark, R A; Gal, J; Gueorguieva, E; Hlatshwayo, T; Juhasz, K; Kalinka, G; Komati, F S; Krasznahorkay, A; Lawrie, J J; Lipoglavsek, M; Maliage, S M; Malwela, T; Molnar, J; Murray, S H T; Ntshangase, S; Nyako, B A; Ramashidza, M; Sharpey-Schafer, J F; Scheurer, J N; Shirinda, O; Timar, J; Vymers, P; Zolnai, L

    2006-01-01

    The DIAMANT light charged-particle detector will be coupled with the AFRODITE γ-ray spectrometer at iThemba LABS under a bilateral agreement between South Africa and Hungary. As a first step, the standalone 'Chessboard' section of DIAMANT has been integrated with AFRODITE in order to study incomplete fusion reactions instigated by beams of 13 C ions incident on targets of 170 Er and 176 Yb. A fuller implementation of DIAMANT with AFRODITE will take place in due course

  12. From Cape to Hortobagy: the marriage of DIAMANT with AFRODITE

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, S M [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Bark, R A [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Gal, J [Institute of Nuclear Research, Debrecen (Hungary); Gueorguieva, E [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Hlatshwayo, T [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Juhasz, K [Department of Physics and Engineering, University of Zululand, Private Bag X1001, KwaDlangezwa 3886, Kwa-Zulu Natal (South Africa); Kalinka, G [Institute of Nuclear Research, Debrecen (Hungary); Komati, F S [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Krasznahorkay, A [Institute of Nuclear Research, Debrecen (Hungary); Lawrie, J J [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Lipoglavsek, M [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Maliage, S M [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Malwela, T [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Molnar, J [Institute of Nuclear Research, Debrecen (Hungary); Murray, S H T [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Ntshangase, S [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Nyako, B A [Institute of Nuclear Research, Debrecen (Hungary); Ramashidza, M [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Sharpey-Schafer, J F [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Scheurer, J N [CNRS-IN2P3-Universite de Bordeaux I, 33175 Gradignan Cedex (France); Shirinda, O [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Timar, J [Institute of Nuclear Research, Debrecen (Hungary); Vymers, P [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Zolnai, L [Institute of Nuclear Research, Debrecen (Hungary)

    2006-07-15

    The DIAMANT light charged-particle detector will be coupled with the AFRODITE {gamma}-ray spectrometer at iThemba LABS under a bilateral agreement between South Africa and Hungary. As a first step, the standalone 'Chessboard' section of DIAMANT has been integrated with AFRODITE in order to study incomplete fusion reactions instigated by beams of {sup 13}C ions incident on targets of {sup 170}Er and {sup 176}Yb. A fuller implementation of DIAMANT with AFRODITE will take place in due course.

  13. Probing a variety of nuclear phenomena with Diamant and Afrodite

    International Nuclear Information System (INIS)

    Mullins, S.M.; Lawrie, J.J.; Bark, R.A.; Gueorguieva, E.; Komati, F.S.; Murray, S.H.T.; Papka, P.; Sharpey-Schafer, J.F.; Nyako, B. M.; Gal, J.; Juhasz, K.; Krasznahorkay, A.; Zolnai, L; Molnar, J.; Timar, J.; Hlatshwayo, T.; Lipoglavšek, M.; Maliage, S.M.; Malwela, T.; Ntshangase, S.S.; Ramashidzha, T.M.; Shirinda, O.; Vymers, P.; Scheurer, J.N.

    2007-01-01

    The Diamant light-charged-particle detector has been coupled with the Afrodite γ-ray spectrometer through a project funded under an ongoing bilateral agreement between Hungary and South Africa. A number of measurements have been carried out at iThemba LABS with a variety of beams supplied by Separated Sector Cyclotron accelerator. These include studies of incomplete fusion reactions, high-K metastable states in stable hafnium nuclei, chiral structures in silver nuclei and superdeformation in "3"2S. The analysis of these data-sets is at various stages of completion and the latest results will be presented. Plans for future measurements will also be discussed.

  14. Diamants de guerre — pour en finir | CRDI - Centre de recherches ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    22 juil. 2011 ... Ce que nous savons, c'est que 75 % des diamants à joaillerie du monde proviennent de l'Afrique et que l'União Nacional para a Independência Total de ... 37 gouvernements et l'industrie du diamant ont lancé une série de réunions avec des ONG afin de créer un régime international de certification des ...

  15. El silencio abyecto en la plaza del diamante

    Directory of Open Access Journals (Sweden)

    Miaowei Weng

    2018-05-01

    Full Text Available El artículo examina los roles de género impuestos a las mujeres en España bajo el régimen franquista. Revisita la novela de La plaza del Diamante, escrita por Mercè Rodoreda en 1962, y descifra el silencio de la protagonista en el contexto de la posguerra española. A partir de la concepción de lo abyecto de Julia Kristeva, explora cómo el silencio se vuelve informativo sobre la resistencia mental de la protagonista contra la imposición patriarcal, la impotencia que una mujer común siente bajo el franquismo y el crecimiento gradual de la subjetividad femenina.

  16. Synthesis of carbon nanotubes by CVD method using iron and molybdenum-based catalysts supported on ceramic matrices;Sintese de nanotubos de carbono por CVD utilizando catalisadores a base de ferro e molibdenio suportados em matrizes ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Ana Paula de Carvalho

    2010-07-01

    Molybdenum is known for its synergistic effect in the synthesis of carbon nanotubes (CNs) by chemical vapor deposition (CVD method). When added to typical catalysts like iron, nickel, and cobalt, even in small quantities, it is increases the yield of these nanostructures. The presence of Mo also has an influence on the type and number of CN walls formed. Although this effect is widely documented in the literature, there is not yet a consensus about the mechanism of action of molybdenum in catalytic systems. The objective of the present work is to study the influence of molybdenum on the catalytic activity of iron nanoparticle-based catalysts supported on magnesium oxide (Fe/MgO system) in the synthesis of carbon nanotubes by the CVD method. The Mo concentration was systematically varied from null to molar ratio values four times greater than the quantity of Fe, and the obtained material (catalysts and carbon nanotubes) were broadly characterized by different techniques. In order to also study the influence of the preparation method on the final composition of the catalytic system phases, the catalytic systems (Fe/MgO e FeMo{sub x}/MgO) were synthesized by two different methods: co-precipitation and impregnation. The greatest CN yields were observed for the catalysts prepared by coprecipitation. The difference was attributed to better dispersion of the Fe and Mo phases in the catalyst ceramic matrix. In the precipitation stage, it was observed the formation of layered double hydroxides whose concentration increased with the Mo content up to the ratio of Mo/Fe equal to 0.2. This phase is related to a better distribution of Fe and Mo in this concentration range. Another important characteristic observed is that the ceramic matrix is not inert. It can react both with Fe and Mo and form the iron solid solution in the magnesium oxide and the phases magnesium-ferrite (MgFe{sub 2}0{sub 4}) and magnesium molybdate (MgMo0{sub 4}). The MgFe{sub 2}0{sub 4} phase is observed in

  17. Simulación de estructuras de carbono, entre el grafito y el diamante

    OpenAIRE

    Alonso Sanz, Lydia

    2017-01-01

    El carbono puro es uno de los materiales inorgánicos más importantes. Una de las razones es que el carbono existe en diferentes formas alotrópicas, como el grafito, el diamante, los fullerenos o los nanotubos de carbono. Aunque todas las formas sean carbono, tienen propiedades muy diferentes, por ejemplo el diamante es el material más duro que se conoce, mientras que el grafito es uno de los materiales más blandos. Entre los materiales de carbono puro destacan los carbones porosos que se prod...

  18. Merger of the DIAMANT Light Charge Particle Detector into the AFRODITE Data Acquisition System

    International Nuclear Information System (INIS)

    Murray, S.H.T.; Mullins, S.M.; Bark, R.A.; Gueorguieva, E.; Lawrie, J.J.; Pilcher, J.V.; Sharpey-Schafer, J.F.; Gal, J.; Kalinka, G.; Krasznahorkay, A.; Molnar, L.; Nyako, B. M.; Timar, J.; Zolnai, L.; Hlatshwayo, T.; Juhasz, K.; Komati, F.S.; Malwela, T.; Ntshangase, S.; Shirinda, O.

    2005-01-01

    The Chessboard section of the DIAMANT CsI detector array has been merged into the AFRODITE γ-ray spectrometer acquisition system. The details of the data acquisition merging is explained together with how consistency is maintained and ensured between the two distinct systems

  19. Highly segmented CVD diamond detectors and high-resolution momentum measurements in knockout reactions; Hochsegmentierte CVD Diamant Detektoren und hochaufloesende Impulsmessungen in Knockout Reaktionen

    Energy Technology Data Exchange (ETDEWEB)

    Schwertel, Sabine

    2009-11-26

    In recent years knockout reactions have proven to be important tools for investigations of the structure of light exotic nuclei. In spring 2006 an experiment was performed with the fragment separator at GSI in Darmstadt to extend this method to medium-mass nuclei with energies of about 400 AMeV. An experiment with a stable and well-known {sup 48}Ca primary beam was performed as a reference. The FRS was set for the reaction {sup 56}Ti{yields}{sup 55}Ti. Because of the high acceptance of the FRS, mother and daughter nuclei of one-neutron knockout reactions in the Sc isotopes {sup 51,52,53,54,55}Sc were also transported with high efficiency. These are investigated in the first part of this thesis. Inclusive cross sections of 77(10) mbarn for one-neutron knockout from {sup 48}Ca and 78(12) mbarn, 99(15) mbarn, 101(15) mbarn, 113(17) mbarn and 72(14) mbarn for knockout from {sup 51,52,53,54,55}Sc, respectively, were measured for the first time. For the Sc isotopes the reduction factors are close to 1. For the one-neutron knockout reactions in {sup 48}Ca and the Sc isotopes, respectively, the momentum distributions could be measured with a relative resolution of 0.17-0.27 %. From the momentum distributions spectroscopic factors of the involved orbitals could be extracted. In the future, further knockout experiments should be performed using the R{sup 3}B setup at FAIR. The available beam intensity will be up to four orders of magnitude higher. As the beam has to be tracked from the dispersive plane of the Super-FRS up to the R{sup 3}B target, radiation hard detectors are needed. In the framework of this thesis extensive measurements were performed at the tandem accelerator in Munich with numerous small (10 x 10 mm{sup 2}) test detectors. Samples using new manufacturing methods were characterized. A dose of some 10{sup 11} ions/mm{sup 2} was determined as a limit for the exposure of the material with heavy ions of high ionisation density. It could be shown that even highly segmented detectors with an efficiency {epsilon}>98 % could be built from this material. The diamond detectors were segmented in our laboratory and achieved a time resolution of {sigma}{sub t}=75 ps. Medium-size (25.4 x 25.4 mm{sup 2}) micro-strip detectors were tested at the FRS and at the ALADIN/LAND setup at GSI. The obtained position resolution was in the range of the strip size of 200 {mu}m. First full-size detectors (50 x 50 mm{sup 2}) will be completed soon. (orig.)

  20. Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza Geology of Cerro Guanaquero region, Diamante River, Mendoza

    OpenAIRE

    Federico Fuentes; Victor A. Ramos

    2008-01-01

    El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánic...

  1. CVD in nuclear energy

    International Nuclear Information System (INIS)

    Nickel, H.

    1981-08-01

    CVD-deposited pyrocarbon, especially the coatings of nuclear fuel kernels show a structure depending on many parameters such as deposition temperature, nature and pressure of the pyrolysis gas, nature of the substrate, geometry of the deposition system, etc. Because of the variety of pyrocarbon different characterization methods have been developed or qualified for this new application. Additionally classical characterization procedures are available. Beside theoretical aspects concerning the formation and deposition mechanism of pyrocarbon from the gas phase the behaviour of such coatings under irradiation with fast neutrons is discussed. (orig.) [de

  2. Uma análise comparativa entre sistemas de inovação e o diamante de Porter na abordagem de arranjos produtivos locais A comparative analysis between innovation systems and Porter's diamond on the local clusters approach

    Directory of Open Access Journals (Sweden)

    Sebastião Décio Coimbra de Souza

    2006-04-01

    Full Text Available Neste trabalho apresenta-se uma avaliação comparativa entre as abordagens de Sistemas de Inovação e o Diamante de Porter para análise da competitividade de aglomerados e sistemas produtivos locais. Inicialmente, é feita uma revisão das abordagens mais recentes para análise de sistemas produtivos locais, regionais ou setoriais, considerando conceitos evolucionários. A seguir, as características distintivas das abordagens de Sistemas de Inovação e do Diamante de Porter são comparadas e comentadas. Em síntese, enquanto a abordagem de Sistemas de Inovação enfatiza as características de cooperação e interação entre instituições que suportam o desenvolvimento e o avanço tecnológico e organizacional, o Diamante privilegia o contexto competitivo local/setorial e os aspectos de mercado em perspectiva internacional. Ambas as abordagens consideram a infra-estrutura e os fluxos institucionais (formais e informais como precondição fundamental para o desenvolvimento econômico. Como uma alternativa para suprir certas lacunas verificadas em ambas as abordagens na análise da competitividade em arranjos produtivos locais, sugere-se uma perspectiva evolucionária.In this work is presented a comparative evaluation between Innovation Systems and Porter's Diamond approaches for competitive analysis in Clusters and Local Productive Systems. Initially it is done a brief review of the recent approaches to regional, local and sectorial productive systems considering evolutionary technical-economic concepts. Then, the distinctive characteristics between Innovation Systems and Porter's Diamond approaches are compared and commented. In synthesis, while the Innovation System approach the characteristics of cooperation and interaction between institutions that support the development and the technological and organizacional advance, the Diamond privileges the local/setorial competitive context and the aspects of international market. However, the

  3. A crise dos negócios do diamante e as respostas dos homens de fortuna no Alto Jequitinhonha, décadas de 1870-1890

    Directory of Open Access Journals (Sweden)

    Marcos Lobato Martins

    2008-09-01

    Full Text Available Este trabalho aborda a crise da mineração em Diamantina no período 1870-1890 e os impactos que ela gerou sobre os negócios dos grandes mineradores e negociantes de diamante. A ênfase recai sobre a trajetória regional da indústria de lapidação, que representou tentativa de agregar valor às gemas extraídas nas lavras do Alto Jequitinhonha. Também são analisados os investimentos que os homens de fortuna fizeram em firmas comerciais e industriais (principalmente fábricas de tecidos e os projetos de desenvolvimento regional elaborados por empresários diamantinenses neste período. O trabalho utiliza fontes locais diversas como inventários, processos de falências, contratos, jornais, discursos e panfletos políticos.This paper examines the mining crisis in Diamantina between 1870 and 1890 and the consequences it produced on the great miners and diamond dealer's business. It enphazises the regional trajectory of the lapidary industry, that represented an attempt to aggregate value to the gemstones mined in the Upper-Jequitinhonha. The paper also analyses the investments carried out by the businessmen in commercial and industrial partnerships (especially fabric factories, as well as the regional development projects fostered by Diamantina's entrepreneurs in the period. This paper utilizes several local sources like inventories, liquidations processes, contracts, newspapers, political speeches and political pamphlets.

  4. CVD Diamond Sensors In Detectors For High Energy Physics

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00334150; Trischuk, William

    At the end of the next decade an upgrade of the Large Hadron Collider (LHC) to High Luminosity LHC (HL-LHC) is planned which requires the development of new radiation tolerant sensor technology. Diamond is an interesting material for use as a particle detector in high radiation environments. The large band gap ($5.47\\,\\text{eV}$) and the large displacement energy suggest that diamond is a radiation tolerant detector material. In this Thesis the capability of Chemical Vapor Deposition (CVD) diamond as such a sensor technology is investigated. The radiation damage constant for $800\\,\\text{MeV}$ protons is measured using single crystalline CVD (scCVD) and polycrystalline CVD (pCVD) diamonds irradiated to particle fluences up to $12 \\times 10^{15}\\,\\text{p/cm}^2$. In addition the signal response of a pCVD diamond detector after an irradiation to $12 \\times 10^{15}\\,\\text{p/cm}^2$ is investigated to determine if such a detector can be operated efficiently in the expected HL-LHC environment. By using electrodes em...

  5. Using Gamma Irradiation To Induce New Mutants In Potatoes Cv. Diamant Through Tissue Culture Technique

    International Nuclear Information System (INIS)

    Sharabash, M.T.; Ali, Amina A. M.; Ahmed, F. A.; Afifi, Abd El-Moneim M.

    2004-01-01

    The excess salt, usually NaCl, inhibits potato plant growth and decreases tubers yield. The use of gamma irradiation to induce new mutants in potato cv. Diamant through tissue culture technique was the main task of this study. Sterilized meristemic tips of potato tubers were cultured on aseptic solid MS-medium, pH 5.7, and were incubated at 20 ± 2 d eg C and 16 hrs day length of 3000-Lux light intensity, to produce virus-free plantlets. Micro-propagation started after 6-8 weeks and plantlets were sub-cultured every 3-4 weeks to increase plantlets population. Plantlets were exposed to 0, or 40 Gy, dose rate 27.7 rad / sec., using Co 60 source at the National Center for Research and Radiation Technology, Cairo, Egypt. Irradiated and unirradiated plantlets were transplanted into 60 ml liquid 1/2MS-medium, pH 5.7, and supplemented with 0, 2000 or 4000 ppm NaCl. And, they were incubated for 2 weeks under the same conditions of temperature and light till the new plantlets were grown up. Healthy plantlets were selected, and micro-propagated up to the sixth vegetative generation (M 1 V 6 ), under the same conditions of salinity and incubation conditions Thereafter, the plantlets were transferred to tuberization liquid 1/2MS-medium, supplemented with the same mentioned concentrations of NaCl, to obtain microtubers. The microtubers were collected after 6-8 weeks and preserved at 10 deg C for 3 months approximately, to break the dormancy. Sprouted microtubers were sown to obtain minitubers, and subsequently macrotubers. All cultures were performed in 30-cm pots in a protected greenhouse, and were irrigated with the same concentrations of NaCl. It could be elicited that cv. Diamant is salinity sensitive. This was evidenced by the decrease in the average number of tubers per plant and average fresh weight of tuber under salinity stress up 4000 ppm NaCl, comparing to unsaline control treatment. Potato plants, which still healthy and produced tubers under salinity stress up to

  6. Improved performances of CsI(Tl) scintillation detectors for DIAMANT II multidetector

    International Nuclear Information System (INIS)

    Scheurer, J-N.; Virassamynaiken, E.; Kalinka, G.; Nyako, B.M.; Gal, J.

    1997-01-01

    The scintillation detectors used for light particle discrimination require a careful optimization of performances of the scintillator-light guide assembly to ensure a good light channeling to photodiode. To obtain a good energy resolution and a good peak symmetry such an optimization has been carried out on the 'Chess-Board' detectors consisting of 25 units, a system which is to be utilised as additional detector at EUROBALL. Recently, such optimization has been realised also for the detectors of the DIAMANT II assembly. This multidetector includes the 'Chess-Board' and constitutes a more segmented version of DIAMANT with 82 detectors instead of 54 detectors. The ensemble of these charged light particle detectors is to be incorporated in EUROBALL. For the first newly conditioned 34 detectors the light collection and the energy resolution measured for 5.5 MeV α particles equal 70 ± 3% and 2.4 ± 0.2%, respectively. The best result was obtained with 232 U as a α particle source and using a 6 μs time constant amplifier. The line shape of the spectrum peaks can be described by the function 1/(E 0 - E) 1-α convoluted with Lorentz and Gauss functions. For the peak of 8.7 MeV, measured with the CsI (Tl) detector, the asymmetry is as low as α 0.02 while the Gaussian and Lorentzian widths are given by 2 Γ/E 0 0.005 and 2.35 σ/E 0 = 0.019

  7. Crescimento de diamante dopado com Boro para eletrodos de uso em eletroquímica

    Directory of Open Access Journals (Sweden)

    Leide Lili Gonçalves da Silva

    1999-04-01

    Full Text Available Boron-doped polycrystalline diamond films have been deposited over silicon substrate by hot-filament chemical-vapor-deposition process. A gas mixture of 0,5 vol. % methane and 1 vol. % methanol on hydrogen at a pressure of 50 Torr, have been used. Boric oxide dissolved in methanol have been used as the boron doping source during the diamond growth process. Raman spectroscopy and Scanning Electron Microscopy (SEM have been performed on the samples. A change of Raman spectra with film doping was observed. The diamond characteristic line at 1333 cm-1 down shifted and its intensity decreased as the film resistivity decreased. On the other hand, a broad peak around 1220 cm-1 appeared and its intensity increased with decreasing film resistivity. No modifications on films morphology have been observed with different boron doping level. The grains were well-faceted with 2 mm average size

  8. Dispersion Curves for Phonons in Diamond; Courbes de Dispersion des Phonons dans le Diamant; Krivye dispersii dlya fononov v almaze; Curvas de Dispersion de los Fonones en el Diamante

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J. L.; Wenzel, R. G.; Yarnell, J. L. [Los Alamos Scientific Laboratory, Los Alamos, NM (United States)

    1965-04-15

    A three-axis neutron diffraction spectrometer at the Los Alamos Omega West Reactor has been used to measure the dispersion curves for phonons propagating in the [100] and [111] directions in diamond. All measurements were made at room temperature. The sample was a type Ha brown industrial diamond weighing 242.8 carats (48.56 g). A neutron diffraction study showed it to consist of a large single crystal with a mosaic spread of - 1 Degree-Sign full width at half maximum, plus two small regions misoriented by 3 and 5 Degree-Sign . The spectrometer was programmed for ''constant-Q'' operation. In all cases, the energy of the incident neutrons was fixed and the scattered neutrons lost energy. Sufficient intensity at an incident energy high enough to excite the optical modes of diamond was obtained by the use of the (1122) reflection of a beryllium monochromator. Uncertainties in the measured frequencies are estimated to be of the order of 2-3%. The most striking result of these measurements is the verification of the predictions, based on infrared absorption and specific heat data, that diamond is not homologous to silicon and germanium. The lack of homology is manifested principally in the behaviour of the transverse branches. The transverse acoustic branches are relatively much higher in diamond than in silicon and germanium. The transverse optical branches are relatively lower, so that in diamond the highest branch is the longitudinal optical rather than the transverse optical. Frequencies at the zone boundaries are in reasonable agreement with those predicted from infrared absorption data, although the identification of the polarizations is different. (author) [French] Les auteurs ont utilise un spectrometre triaxial pour la diffraction des neutrons produits par le reacteur Omega West de Los Alamos en vue de determiner plusieurs courbes de dispersion des phonons se deplacant dans des directions de symetrie a l'interieur du, diamant. Toutes les mesures ont ete

  9. Contribution to data acquisition software of Eurogram and Diamant multi detectors in an Unix/VXWorks environment; Contribution aux logiciels d`acquisition de donnees des multidetecteurs Eurogam et Diamant dans un environnement reparti Unix/VXWorks

    Energy Technology Data Exchange (ETDEWEB)

    Diarra, C

    1994-06-01

    Questions on nuclear matter, need to have new performant equipments. Eurogram is a 4 PI gamma radiations multi detector and a precious tool in gamma spectroscopy, but it is necessary to use a charged particles detector and in this aim Diamant is an Eurogram partner. These two multi detectors needed special software data acquisition systems. The whole of acquisition control and management is based on sun stations with unix system. 56 figs., 64 refs.

  10. Contribution to data acquisition software of Eurogram and Diamant multi detectors in an Unix/VXWorks environment

    International Nuclear Information System (INIS)

    Diarra, C.

    1994-06-01

    Questions on nuclear matter, need to have new performant equipments. Eurogram is a 4 PI gamma radiations multi detector and a precious tool in gamma spectroscopy, but it is necessary to use a charged particles detector and in this aim Diamant is an Eurogram partner. These two multi detectors needed special software data acquisition systems. The whole of acquisition control and management is based on sun stations with unix system. 56 figs., 64 refs

  11. Effects of Different Systemic Insecticides in Carotenoid Content, Antibacterial Activity and Morphological Characteristics of Tomato (Solanum lycopersicum var Diamante)

    OpenAIRE

    LEXTER R. NATIVIDAD; Maria Fatima T. Astrero; Lenard T. Basinga; Maria Karysa G. Calang

    2014-01-01

    This study aimed to determine the effects of different systemic insecticides in tomato (Lycopersicon esculentum var. Diamante). The study also assessed different systemic insecticides used in other plants in their effectiveness and suitability to tomato by evaluating the carotenoid content and antibacterial activity of each insecticide. Morphological characteristics such as the weight, the number and the circumference of tomato fruits and the height of the plant were also observed. Moreover, ...

  12. CVD - main concepts, applications and restrictions

    International Nuclear Information System (INIS)

    Bliznakovska, B.; Milosevski, M.; Krawczynski, S.; Meixner, C.; Koetter, H.R.

    1993-01-01

    Despite of the fact that the existing literature covering the last two decades is plentiful with data related to CVD, this document is an attempt to provide to a reader a concise information about the nature of CVD technique at production of technologically important materials as well as to point at special references. The text is devided into three separate sections. The first section, The Main Features of CVD, is intended to give a complete comprehensive picture of the CVD technique through process description and characterization. The basic principles of thermodynamics, CVD chemical reactions classification, CVD chemical kinetics aspects and physics of CVD (with particular attention on the gas-flow phenomena) are included. As an additional aspect, in CVD unavoidable aspect however, the role of the coating/substrate compatibility on the overall process was outlined. The second section, CVD Equipment, concerns on the pecularities of the complete CVD unit pointing out the individual significances of the separate parts, i.e. pumping system, reactor chamber, control system. The aim of this section is to create to a reader a basic understanding of the arising problems but connected to be actual CVD performance. As a final goal of this review the reader's attention is turned upon the CVD applications for production of an up-to-date important class of coatings such as multilayer coatings. (orig.)

  13. CVD diamond detectors and dosimeters

    International Nuclear Information System (INIS)

    Manfredotti, C.; Fizzotti, F.; LoGiudice, A.; Paolini, C.; Oliviero, P.; Vittone, E.; Torino Univ., Torino

    2002-01-01

    Natural diamond, because of its well-known properties of tissue-equivalence, has recorded a wide spreading use in radiotherapy planning with electron linear accelerators. Artificial diamond dosimeters, as obtained by Chemical Vapour Deposition (CVD) could be capable to offer the same performances and they can be prepared in different volumes and shapes. The dosimeter sensitivity per unit volume may be easily proved to be better than standard ionization microchamber. We have prepared in our laboratory CVD diamond microchamber (diamond tips) in emispherical shape with an external diameter of 200 μm, which can be used both as X-ray beam profilometers and as microdosimeters for small field applications like stereotaxy and also for in vivo applications. These dosimeters, which are obtained on a wire substrate that could be either metallic or SiC or even graphite, display good performances also as ion or synchrotron X-rays detectors

  14. Mineralogical analysis of auriferous ores from the El Diamante mine, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Bustos Rodriguez, Humberto, E-mail: hbustos@ut.edu.co; Oyola Lozano, Dagoberto; Rojas Martinez, Yebrayl A. [Universidad del Tolima, Departamento de Fisica (Colombia); Perez Alcazar, German A. [Universidad del Valle, Departamento de Fisica (Colombia); Flege, Stefan; Balogh, Adam G. [Darmstadt University of Technology, Institute of Materials Science (Germany); Cabri, Louis J. [Cabri Consulting Inc. (Canada); Tubrett, Michael [Memorial University of Newfoundland (Canada)

    2007-02-15

    X-ray diffraction (XRD), Moessbauer spectrometry (MS), secondary ions mass spectroscopy (SIMS) and laser-ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) were used to study mineral samples of Colombian auriferous ores collected from the 'El Diamante' mine, located in the municipality of Guachavez-Narino, in Colombia. The samples were prepared as polished thin sections and polished sections. From XRD data, quartz, sphalerite and pyrite were detected and their respective cell parameters were estimated. From MS analyses, pyrite, arsenopyrite and chalcopyrite were identified; their respective hyperfine parameters and respective texture were deduced. Multiple regions of approximately 200 x 200 {mu}m in each sample were analyzed with SIMS; the occurrence of 'invisible gold' associated mainly with pyrite and secondarily with arsenopyrite could thus be assigned. It was also found that pyrite is of the arsenious type. Spots from 30 to 40 {mu}m in diameter were analyzed with LAM-ICP-MS for pyrite, arsenopyrite and sphalerite; Au is 'homogeneously' distributed inside the structure of the arsenious pyrite and the arsenopyrite (not as inclusions); the chemical composition indicates similarities of this 'invisible gold', forming a solid solution with arsenious pyrite and arsenopyrite. One hundred nineteen and 62 ppm of 'invisible gold' was quantified in 21 spots analyzed on pyrite and in 14 spots on arsenopyrite, respectively.

  15. Mineralogical analysis of auriferous ores from the El Diamante mine, Colombia

    International Nuclear Information System (INIS)

    Bustos Rodriguez, Humberto; Oyola Lozano, Dagoberto; Rojas Martinez, Yebrayl A.; Perez Alcazar, German A.; Flege, Stefan; Balogh, Adam G.; Cabri, Louis J.; Tubrett, Michael

    2007-01-01

    X-ray diffraction (XRD), Moessbauer spectrometry (MS), secondary ions mass spectroscopy (SIMS) and laser-ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) were used to study mineral samples of Colombian auriferous ores collected from the 'El Diamante' mine, located in the municipality of Guachavez-Narino, in Colombia. The samples were prepared as polished thin sections and polished sections. From XRD data, quartz, sphalerite and pyrite were detected and their respective cell parameters were estimated. From MS analyses, pyrite, arsenopyrite and chalcopyrite were identified; their respective hyperfine parameters and respective texture were deduced. Multiple regions of approximately 200 x 200 μm in each sample were analyzed with SIMS; the occurrence of 'invisible gold' associated mainly with pyrite and secondarily with arsenopyrite could thus be assigned. It was also found that pyrite is of the arsenious type. Spots from 30 to 40 μm in diameter were analyzed with LAM-ICP-MS for pyrite, arsenopyrite and sphalerite; Au is 'homogeneously' distributed inside the structure of the arsenious pyrite and the arsenopyrite (not as inclusions); the chemical composition indicates similarities of this 'invisible gold', forming a solid solution with arsenious pyrite and arsenopyrite. One hundred nineteen and 62 ppm of 'invisible gold' was quantified in 21 spots analyzed on pyrite and in 14 spots on arsenopyrite, respectively.

  16. Growth and characterization of single-crystal CVD diamond for radiation detection applications; Synthese et caracterisation de diamants monocristallins pour applications de detecteur de rayonnements

    Energy Technology Data Exchange (ETDEWEB)

    Tranchant, N

    2008-01-15

    This work aimed at the study of the synthesis of single crystal diamond using the Microwave enhanced Chemical Vapour Deposition technique (MPCVD). The work enabled the development and optimisation of the growth conditions, from the study of the crystalline quality, of the material purity, and of its electronic properties. The assessment of the transport properties was the most determinant: the use of the time of flight (TOF) technique has enabled the measurement of the carrier mobilities and of their kinetic properties as a function of the temperature. When coupled with collected charge efficiency measurements, the work led to remarkable carrier mobility values obtained in the synthesised crystals (3000 cm{sup 2}.V-1.s{sup -1}). Prepared samples were mounted as detection devices and used successfully in real conditions for the monitoring of ultra-fast pulses, as well as for neutron fluency monitoring, and for medical dosimeters for radiotherapy applications. (author)

  17. Diagnóstico y ordenamiento territorial: el caso del departamento Diamante (Entre Ríos, Argentina

    Directory of Open Access Journals (Sweden)

    Lisandra Pamela Zamboni

    2014-12-01

    Full Text Available Las transformaciones en el uso de la tierra en socioecosistemas pueden ser estudiadas mediante algunas herramientas propias de la ordenación del territorio. El objetivo del presente trabajo fue caracterizar y diagnosticar los principales actores y procesos involucrados en la conformación y dinámica del departamento Diamante (Entre Ríos, Argentina. Como ejes de trabajo se tuvieron la delimitación del área de estudio que contemple la capacidad/potencial del territorio y el medio en el que se enmarca, la caracterización del área de estudio mediante la definición de subsistemas (ambiental, social, económico y marco legal e institucional y variables indicadoras del sistema territorial, el diagnóstico del territorio, incluyendo la identificación de los elementos territoriales de interés, revisión de normativas vigentes, y una fase prospectiva seguida de una propositiva. Se considera que el Departamento Diamante representa un sistema complejo, con subsistemas que interactúan recíprocamente diferenciando un sector de “tierras altas” y un “sector de islas”, cada uno con una aparente conformación y dinámica. A partir de los datos e interpretaciones realizadas fue posible proponer una zonificación del área de estudio y la sistematización y espacialización de las variables en un sistema de información geográfica que actúe como soporte para la elaboración propuestas de ordenamiento territorial y para la gestión del Departamento Diamante (Entre Ríos, Argentina.

  18. Delaminated Transfer of CVD Graphene

    Science.gov (United States)

    Clavijo, Alexis; Mao, Jinhai; Tilak, Nikhil; Altvater, Michael; Andrei, Eva

    Single layer graphene is commonly synthesized by dissociation of a carbonaceous gas at high temperatures in the presence of a metallic catalyst in a process known as Chemical Vapor Deposition or CVD. Although it is possible to achieve high quality graphene by CVD, the standard transfer technique of etching away the metallic catalyst is wasteful and jeopardizes the quality of the graphene film by contamination from etchants. Thus, development of a clean transfer technique and preservation of the parent substrate remain prominent hurdles to overcome. In this study, we employ a copper pretreatment technique and optimized parameters for growth of high quality single layer graphene at atmospheric pressure. We address the transfer challenge by utilizing the adhesive properties between a polymer film and graphene to achieve etchant-free transfer of graphene films from a copper substrate. Based on this concept we developed a technique for dry delamination and transferring of graphene to hexagonal boron nitride substrates, which produced high quality graphene films while at the same time preserving the integrity of the copper catalyst for reuse. DOE-FG02-99ER45742, Ronald E. McNair Postbaccalaureate Achievement Program.

  19. Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza

    OpenAIRE

    Federico Fuentes; Victor A. Ramos

    2008-01-01

    El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánic...

  20. [Biomedical health care in Angola and in the Companhia de Diamantes de Angola, circa 1910-1970].

    Science.gov (United States)

    Varanda, Jorge

    2014-01-01

    The scope of this paper is to analyze the provision of biomedical care in Angola during the activities of the Companhia de Diamantes de Angola. A comparative analysis of public health policies and practices of various colonial actors, such as the health services of the Company, its state counterpart and other colonial companies, will reveal differences in investment in health, namely in health facilities, personnel and treatment. This survey as well as the living conditions highlight the idiosyncratic and central nature of the health services of the Company in terms of morbidity and mortality in Angola, and the importance of these representations for a caregiving empire.

  1. Layered hydrothermal barite-sulfide mound field, East Diamante Caldera, Mariana volcanic arc

    Science.gov (United States)

    Hein, James R.; de Ronde, Cornel E. J.; Koski, Randolph A.; Ditchburn, Robert G.; Mizell, Kira; Tamura, Yoshihiko; Stern, Robert J.; Conrad, Tracey; Ishizuka, Osamu; Leybourne, Matthew I.

    2014-01-01

    East Diamante is a submarine volcano in the southern Mariana arc that is host to a complex caldera ~5 × 10 km (elongated ENE-WSW) that is breached along its northern and southwestern sectors. A large field of barite-sulfide mounds was discovered in June 2009 and revisited in July 2010 with the R/V Natsushima, using the ROV Hyper-Dolphin. The mound field occurs on the northeast flank of a cluster of resurgent dacite domes in the central caldera, near an active black smoker vent field. A 40Ar/39Ar age of 20,000 ± 4000 years was obtained from a dacite sample. The mound field is aligned along a series of fractures and extends for more than 180 m east-west and >120 m north-south. Individual mounds are typically 1 to 3 m tall and 0.5 to 2 m wide, with lengths from about 3 to 8 m. The mounds are dominated by barite + sphalerite layers with the margins of each layer composed of barite with disseminated sulfides. Rare, inactive spires and chimneys sit atop some mounds and also occur as clusters away from the mounds. Iron and Mn oxides are currently forming small (caldera, mineralization resulted from focused flow along small segments of linear fractures rather than from a point source, typical of hydrothermal chimney fields. Based on the mineral assemblage, the maximum fluid temperatures were ~260°C, near the boiling point for the water depths of the mound field (367–406 m). Lateral fluid flow within the mounds precipitated interstitial sphalerite, silica, and Pb minerals within a network of barite with disseminated sulfides; silica was the final phase to precipitate. The current low-temperature precipitation of Fe and Mn oxides and silica may represent rejuvenation of the system.

  2. CVD diamond windows for infrared synchrotron applications

    International Nuclear Information System (INIS)

    Sussmann, R.S.; Pickles, C.S.J.; Brandon, J.R.; Wort, C.J.H.; Coe, S.E.; Wasenczuk, A.; Dodge, C.N.; Beale, A.C.; Krehan, A.J.; Dore, P.; Nucara, A.; Calvani, P.

    1998-01-01

    This paper describes the attributes that make diamond a unique material for infrared synchrotron beam experiments. New developments in diamond synthesised by Chemical Vapour Deposition (CVD) promise to extend the range of applications which have been hitherto limited by the availability and cost of large-size single-crystal diamond. Polycrystalline CVD diamond components such as large (100 mm) diameter windows with extremely good transparency over a wide spectral range are now commercially available. Properties of CVD diamond of relevance to optical applications, such as mechanical strength, thermal conductivity and absolute bulk absorption, are discussed. It is shown that although some of the properties of CVD diamond (similar to other polycrystalline industrial ceramics) are affected by the grain structure, currently produced CVD diamond optical components have the quality and performance required for numerous demanding applications

  3. CVD diamond for nuclear detection applications

    CERN Document Server

    Bergonzo, P; Tromson, D; Mer, C; Guizard, B; Marshall, R D; Foulon, F

    2002-01-01

    Chemically vapour deposited (CVD) diamond is a remarkable material for the fabrication of radiation detectors. In fact, there exist several applications where other standard semiconductor detectors do not fulfil the specific requirements imposed by corrosive, hot and/or high radiation dose environments. The improvement of the electronic properties of CVD diamond has been under intensive investigations and led to the development of a few applications that are addressing specific industrial needs. Here, we report on CVD diamond-based detector developments and we describe how this material, even though of a polycrystalline nature, is readily of great interest for applications in the nuclear industry as well as for physics experiments. Improvements in the material synthesis as well as on device fabrication especially concern the synthesis of films that do not exhibit space charge build up effects which are often encountered in CVD diamond materials and that are highly detrimental for detection devices. On a pre-i...

  4. Surface coatings deposited by CVD and PVD

    International Nuclear Information System (INIS)

    Gabriel, H.M.

    1982-01-01

    The demand for wear and corrosion protective coatings is increasing due to economic facts. Deposition processes in gas atmospheres like the CVD and PVD processes attained a tremendous importance especially in the field of the deposition of thin hard refractory and ceramic coatings. CVD and PVD processes are reviewed in detail. Some examples of coating installations are shown and numerous applications are given to demonstrate the present state of the art. (orig.) [de

  5. Ciencia de superficies e ingeniería de películas de diamante: de las propiedades morfológicas a las ópticas

    Directory of Open Access Journals (Sweden)

    Miguel Apátiga

    2003-01-01

    Full Text Available Para efectuar la caracterización morfológica y óptica en películas de diamante se utilizó la microscopía de barrido electrónico (MBE y espectroscopias de transformada de Fourier infrarroja (TFI y Raman. Para esto se depositaron diversas películas de diamante usando la flama de un soplete de oxígeno-acetileno a una temperatura del substrato de 800°C y en atmósfera abierta. Las micrografías MBE muestran que la morfología y espesor de las películas varían según las condiciones empleadas en su obtención. También hay información detallada acerca de la estructura en la superficie del diamante obtenida por espectroscopia infrarroja. De esta manera, se analiza la naturaleza de las especies químicamente absorbidas durante el proceso de crecimiento como resultado de la reacción química: C2H2 + O2 Æ 2CO + H2, llevada a cabo en los primeros instantes de la deposición. Además, se estudió la calidad de las películas mediante espectroscopia Raman, una de las técnicas más sensibles y poderosas, ya que permite distinguir las diferentes fases del carbón. Con esta técnica se obtuvo una banda en 1332 cm-1 que es característica de la estructura sp3 del diamante, la ausencia de señales alrededor de 1560 cm-1 es característico de las películas de diamante de buena calidad. Se presenta también una breve discusión del papel que juegan las especies químicamente absorbidas en los primeros instantes en que se produce la deposición del diamante y durante su proceso de crecimiento

  6. CVD diamond for nuclear detection applications

    International Nuclear Information System (INIS)

    Bergonzo, P.; Brambilla, A.; Tromson, D.; Mer, C.; Guizard, B.; Marshall, R.D.; Foulon, F.

    2002-01-01

    Chemically vapour deposited (CVD) diamond is a remarkable material for the fabrication of radiation detectors. In fact, there exist several applications where other standard semiconductor detectors do not fulfil the specific requirements imposed by corrosive, hot and/or high radiation dose environments. The improvement of the electronic properties of CVD diamond has been under intensive investigations and led to the development of a few applications that are addressing specific industrial needs. Here, we report on CVD diamond-based detector developments and we describe how this material, even though of a polycrystalline nature, is readily of great interest for applications in the nuclear industry as well as for physics experiments. Improvements in the material synthesis as well as on device fabrication especially concern the synthesis of films that do not exhibit space charge build up effects which are often encountered in CVD diamond materials and that are highly detrimental for detection devices. On a pre-industrial basis, CVD diamond detectors have been fabricated for nuclear industry applications in hostile environments. Such devices can operate in harsh environments and overcome limitations encountered with the standard semiconductor materials. Of these, this paper presents devices for the monitoring of the alpha activity in corrosive nuclear waste solutions, such as those encountered in nuclear fuel assembly reprocessing facilities, as well as diamond-based thermal neutron detectors exhibiting a high neutron to gamma selectivity. All these demonstrate the effectiveness of a demanding industrial need that relies on the remarkable resilience of CVD diamond

  7. Fermented dairy food and CVD risk.

    Science.gov (United States)

    Tapsell, Linda C

    2015-04-01

    Fermented dairy foods such as yoghurt and cheese are commonly found in the Mediterranean diet. Recent landmark research has confirmed the effect of the Mediterranean diet on reducing the CVD risk, but the relative contributions of fermented dairy foods have not been fully articulated. The present study provides a review of the relationship between fermented dairy foods consumption and CVD risk in the context of the whole diet. Studies show that people who eat healthier diets may be more likely to consume yoghurt, so there is a challenge in attributing separate effects to yoghurt. Analyses from large population studies list yoghurt as the food most negatively associated with the risk of weight gain (a problem that may lead to CVD). There is some suggestion that fermented dairy foods consumption (yoghurt or cheese) may be associated with reduced inflammatory biomarkers associated with the development of CVD. Dietary trials suggest that cheese may not have the same effect on raising LDL-cholesterol levels as butter with the same saturated fat content. The same might be stated for yoghurt. The use of different probiotic cultures and other aspects of study design remain a problem for research. Nevertheless, population studies from a range of countries have shown that a reduced risk of CVD occurs with the consumption of fermented dairy foods. A combination of evidence is necessary, and more research is always valuable, but indications remain that fermented dairy foods such as cheese and yoghurt are integral to diets that are protective against CVD.

  8. Un análisis del escenario económico del Perú y Chile, desde la perspectiva del doble diamante de la competitividad global

    Directory of Open Access Journals (Sweden)

    Jesús C. Peña-Vinces

    2009-11-01

    Full Text Available Las pequeñas economías, como la peruana y chilena, se encuentran inmersas en la arena global de las economías emergentes, por lo que evaluarlas desde un punto de vista puramente local (Porter1990 sería un enfoque bastante limitado y poco útil. Este hecho hace que el diamante nacional de Porter (1990 resulte, a todas luces, insuficiente para dicho propósito (Moon et al. 1998: 135. Este artículo analiza las economías mencionadas desde un enfoque más global, que incluye tanto el mercado local como el extranjero; es decir, evaluarlo desde la perspectiva del doble diamante de la competitividad internacional propuesta por Moon et al. (1998, y Moon y Lee (2004: 138.

  9. Diamond brazing - interfacial reactions and wetting; Loeten von Diamant - Grenzflaechenreaktionen und Benetzung

    Energy Technology Data Exchange (ETDEWEB)

    Tillmann, W.; Osmanda, A.M.; Yurchenko, S. [Lehrstuhl fuer Werkstofftechnologie, Universitaet Dortmund, Leonhard-Euler-Str. 2, 44227 Dortmund (Germany); Theisen, W. [Ruhr-Universitaet Bochum, Lehrstuhl Werkstofftechnik (Germany)

    2005-08-01

    Diamond tools are increasingly gaining importance as cutting materials for various construction materials. The quality of synthetic diamonds, monocrystalline as well as polycrystalline or CVD-diamonds has been significantly improved over the last years. Integrating these cutting materials requires adequate joining technologies that produce sound joints without exposing the temperature sensitive diamond to too elevated temperatures. The paper highlights current developments in the joining of synthetic diamonds to steel and cemented carbide. Owing to their covalent atomic bonding diamonds cannot easily be wetted and joined by employing conventional brazing alloys. Hence, active agents are needed to foster an interfacial reaction. Different active filler concepts are presented and discussed regarding their joint formation. The brazing temperatures influence not only possible diamond degradation but also the interfacial decomposition of the diamond due to the formation of corresponding reaction layers.Active brazing, monocrystalline. (Abstract Copyright [2005], Wiley Periodicals, Inc.) [German] Diamantwerkstoffe erlangen zunehmend Bedeutung als Schneidmaterialien in Diamantwerkzeugen fuer die Bearbeitung verschiedener Konstruktionswerkstoffe. Die Qualitaet von synthetischen Diamanten, sowohl monokristallinen als auch polykristallinen oder CVD-Diamantschichten konnte in den letzten Jahren deutlich verbessert werden. Die Integration dieser Schneidstoffe erfordert eine angepasste Fuegetechnologie, die fehlerfreie Verbunde bereitstellt, ohne die gegenueber hohen Temperaturen empfindlichen Diamanten zu hohen Temperaturen auszusetzen. Der Beitrag zeigt aktuelle Entwicklungen in der Fuegetechnik von synthetischen Diamanten mit Stahl und Hartmetall auf. Infolge ihrer kovalenten atomaren Bindungen koennen Diamanten nicht ohne weiteres mit herkoemmlichen Lotwerkstoffen benetzt und gefuegt werden. Daher sind reaktive Elemente notwendig, die eine Grenzflaechenreaktion forcieren

  10. MgO by injection CVD

    International Nuclear Information System (INIS)

    Abrutis, A.; Kubilius, V.; Teiserkis, A.; Bigelyte, V.; Vengalis, B.; Jukna, A.; Butkute, R.

    1997-01-01

    Epitaxial YBa 2 Cu 3 O 7 layers with 45 in-plane orientation have been grown by injection CVD on MgO substrates polished off-axis to within 1.4-1.9 of the [100] direction. This new single-source CVD process is based on computer-controlled injection of precise microdoses of a metal-organic precursor solution into a CVD reactor. A wide range of solution compositions was tested to investigate compositional effects on phase purity, surface morphology, texturing and superconducting properties of the prepared films. The highest quality films with pure 45 texture had a smooth surface, zero resistance T c (R=0) of 88-89 K, and critical current density J c (77 K) above 10 6 A/cm 2 . (orig.) and critical current density J c (77 K) above 10 6 A/cm 2 . (orig.)

  11. CVD mechanism of pyrolytic boron nitride

    International Nuclear Information System (INIS)

    Tanji, H.; Monden, K.; Ide, M.

    1987-01-01

    Pyrolytic boron nitride (P-BN) has become a essential material for III-V compound semiconductor manufacturing process. As the demand from electronics industry for larger single crystals increases, the demand for larger and more economical P-BN components is growing rapidly. P-BN is manufactured by low pressure CVD using boron-trihalides and ammonia as the reactants. In spite that P-BN has been in the market for quite a long time, limited number of fundamental studies regarding the kinetics and the formation mechanism of P-BN have been reported. As it has been demonstrated in CVD of Si, knowledge and both theoretical and empirical modeling of CVD process can be applied to improve the deposition technology and to give more uniform deposition with higher efficiency, and it should also apply to the deposition of P-BN

  12. Síntesis de materiales cerámicos mediante técnicas químicas en fase vapor (CVD

    Directory of Open Access Journals (Sweden)

    Gómez-Aleixandre, C.

    2003-02-01

    los reactivos se efectúa con plasma o con fotones. La técnica permite además sintetizar nuevos productos que no es posible sintetizar por otras vías. Esta característica abre la puerta hacia la síntesis de productos, con propiedades muy específicas de dureza, estabilidad, etc. La presentación se centrará en las diversas aplicaciones de la técnica de CVD, de las que interesa destacar la preparación de capas de carbono cristalino o amorfo (películas de diamante o cuasi-diamante partiendo de una mezcla de metano e hidrógeno activada mediante un plasma. Así mismo, se revisará la obtención de recubrimientos de nitruro de boro con diferente estequiometría dependiendo de las condiciones del proceso. Finalmente, se discuten los condiciones experimentales requeridas para la deposición de nuevos compuestos ternarios dentro del sistema Si-B-C-N (p.e. CBN, SiBN. Estos materiales ternarios pueden presentar propiedades muy diferentes dependiendo de su composición. Por tanto, mediante la elección adecuada de los parámetros experimentales, que determinan la composición y estructura del depósito, es posible conseguir la formación de un material con unas características prefijadas.

  13. Recent results on CVD diamond radiation sensors

    Science.gov (United States)

    Weilhammer, P.; Adam, W.; Bauer, C.; Berdermann, E.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; v. d. Eijk, R.; van Eijk, B.; Fallou, A.; Fish, D.; Fried, M.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knopfle, K. T.; Krammer, M.; Manfredi, P. F.; Meier, D.; LeNormand; Pan, L. S.; Pernegger, H.; Pernicka, M.; Plano, R.; Re, V.; Riester, J. L.; Roe, S.; Roff; Rudge, A.; Schieber, M.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; RD 42 Collaboration

    1998-02-01

    CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking devices, both strip detectors and pixel detectors, will be discussed. Results from beam tests using a diamond strip detector which was read out with fast, 25 ns shaping time, radiation-hard pipeline electronics will be presented.

  14. Graphitization of diamond with a metallic coating on ferritic matrix; Grafitizacao do diamante com revestimento metalico em matriz ferritica

    Energy Technology Data Exchange (ETDEWEB)

    Cabral, Stenio Cavalier; Oliveira, Hellen Cristine Prata de; Filgueira, Marcello, E-mail: stenio@uenf.b [Universidade Estadual do Norte Fluminense (PPGECM/CCT/UENF), Campos dos Goytacazes, RJ (Brazil). Centro de Ciencias e Tecnologia. Programa de Pos Graduacao em Engenharia e Ciencia dos Materiais

    2010-07-01

    Iron is a strong catalyst of graphitization of diamonds. This graphitization occurs mainly during the processing of composites - conventional sintering or hot pressing, and during cutting operations. Aiming to avoid or minimize this deleterious effect, there is increasing use of diamond coated with metallic materials in the production of diamond tools processed via powder metallurgy. This work studies the influence of Fe on diamond graphitization diamond-coated Ti after mixing of Fe-diamonds, hot pressing parameters were performed with 3 minutes/35MPa/900 deg C - this is the condition of pressing hot used in industry for production of diamond tools. Microstructural features were observed by SEM, diffusion of Fe in diamond was studied by EDS. Graphitization was analyzed by X-ray diffraction and Raman spectroscopy. It was found that Fe not activate graphitization on the diamond under the conditions of hot pressing. (author)

  15. Low temperature CVD deposition of silicon carbide

    International Nuclear Information System (INIS)

    Dariel, M.; Yeheskel, J.; Agam, S.; Edelstein, D.; Lebovits, O.; Ron, Y.

    1991-04-01

    The coating of graphite on silicon carbide from the gaseous phase in a hot-well, open flow reactor at 1150degC is described. This study constitutes the first part of an investigation of the process for the coating of nuclear fuel by chemical vapor deposition (CVD)

  16. CVD diamond pixel detectors for LHC experiments

    CERN Document Server

    Wedenig, R; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Runólfsson, O; Russ, J; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trawick, M L; Trischuk, W; Vittone, E; Wagner, A; Walsh, A M; Weilhammer, Peter; White, C; Zeuner, W; Ziock, H J; Zöller, M

    1999-01-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described. (9 refs).

  17. CVD diamond pixel detectors for LHC experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N

    1999-08-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described.

  18. CVD diamond pixel detectors for LHC experiments

    International Nuclear Information System (INIS)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N.

    1999-01-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described

  19. Turbostratic stacked CVD graphene for high-performance devices

    Science.gov (United States)

    Uemura, Kohei; Ikuta, Takashi; Maehashi, Kenzo

    2018-03-01

    We have fabricated turbostratic stacked graphene with high-transport properties by the repeated transfer of CVD monolayer graphene. The turbostratic stacked CVD graphene exhibited higher carrier mobility and conductivity than CVD monolayer graphene. The electron mobility for the three-layer turbostratic stacked CVD graphene surpassed 10,000 cm2 V-1 s-1 at room temperature, which is five times greater than that for CVD monolayer graphene. The results indicate that the high performance is derived from maintenance of the linear band dispersion, suppression of the carrier scattering, and parallel conduction. Therefore, turbostratic stacked CVD graphene is a superior material for high-performance devices.

  20. A DIAMANT Wedding For AFRODITE: Probing Structure and Characterizing Reaction Properties Via Charged-Particle-γ Correlations

    International Nuclear Information System (INIS)

    Mullins, S. M.; Murray, S. H. T.; Bark, R. A.; Gueorguieva, E.; Lawrie, J. J.; Lieder, E. O.; Lieder, R. M.; Papka, P.; Nyako, B. M.; Timar, J.; Berek, G.; Gal, J.; Kalinka, G.; Molnar, J.; Krasznahorkay, A.; Zolnai, L.; Juhasz, K.; Lipoglavsek, M.; Ntshangase, S. S.; Scheurer, J. N.

    2008-01-01

    The DIAMANT-AFRODITE combination has been used to investigate incomplete fusions reactions via the 13 C+ 170 Er entrance channel. The intensity of 176 Hf (populated via the α 3n exit channel) is ∼8% of 178 W (populated via 5n evaporation) which is ∼8 times stronger than that expected from complete fusion. Moreover, 2αxn exit channels leading to Yb nuclei are observed with intensities that are ∼30-to-40% of 176 Hf, for which no yield is expected from complete fusion. A comparison of the intensities from the two-α- and one-α-gated data is consistent with fragmentation of the 13 C beam into (α-α-α-n) which suggests that the population of Yb nuclei results from fusion (or ''massive transfer'') of one the break-up α-particles. A campaign of measurements is scheduled for late 2007 with further investigations planned for 2008, including the continuation of the study of superdeformation in 32 S

  1. Genetic analysis of somaclonal variants and induced mutants of potato ( solanum tuberosum l.) cv. diamant using RAPD markers

    International Nuclear Information System (INIS)

    Afrasiab, H.; Iqbal, J.

    2011-01-01

    The objective of this work was to genetically analyze somaclonal variants and gamma induced mutants of potato ( Solanum tuberosum L.) cv. Diamant using RAPD-PCR technique. In the present work, callus was induced from nodes, inter nodes and leaf explants in MS medium supplemented with NAA (1.0 mg/l) and BAP (0.5 mg/l) and plants were regenerated from 14-20 weeks old calli. For gamma irradiation, ten-week old well proliferating calli were exposed to doses ranging from 5-50 Gy. All the four selected somaclonal variants and five gamma induced mutants were differentiated by banding patterns obtained from 22 primers that generated 140 polymorphic bands. The presence of polymorphic bands in variants and mutants suggest that genetic variation occurred in all the treatments as compared to control. Similarity and clustered analysis were conducted using Jaccard's coefficients and the un-weighted pair-group method using arithmetic averages. The results summarized in a dendrogram, show genetic diversity among the variants and mutants. The study shows that RAPD markers were efficient in discriminating somaclonal variants and induced mutants of potato. (author)

  2. Diamond burr superficial keratectomy in the treatment of visually-significant anterior corneal lesions Ceratectomia superficial com broca de diamante no tratamento de lesões anteriores da córnea

    Directory of Open Access Journals (Sweden)

    João Baptista Nigro Santiago Malta

    2008-06-01

    Full Text Available PURPOSE: To evaluate the efficacy and safety of diamond burr superficial keratectomy in the treatment of visually-significant anterior corneal lesions. METHODS: A retrospective review of 23 eyes (23 patients. Pre- and postoperative visual acuities and refractions, slit-lamp biomicroscopic findings, and the incidence of recurrence of disease after keratectomy were studied. RESULTS: Nineteen eyes had map-dot-fingerprint basement membrane dystrophy and 4 had Salzmann's nodular degeneration. All patients presented with decreased vision, as well as varying degrees of glare, halos, and monocular diplopia. Postoperative follow-up ranged from 3 to 39 months (mean 10.6 months, and no recurrence of the original disease occurred within this period. This procedure improved the best-corrected visual acuity from 20/36 (LogMar 0.250 to 20/24 (LogMar 0.076 by LogMar statistical evaluation (pOBJETIVO: Avaliar a eficácia e segurança da ceratectomia superficial com broca de diamante no tratamento das lesões anteriores da córnea. MÉTODOS: Foi realizado estudo retrospectivo de 23 olhos de 23 pacientes. Foram avaliados acuidade visual e refração pré e pós-operatório, biomicroscopia e incidência de recorrência da doença após ceratectomia. RESULTADOS: Dos 23 olhos avaliados, 19 olhos apresentavam distrofia da membrana basal (map-dot-fingerprint e 4 degeneração nodular de Salzmann. Todos os pacientes apresentavam diminuição da acuidade visual, assim como graus variados de ofuscamento, halos e diplopia monocular. O seguimento pós-operatório variou entre 3 e 39 meses (média de 10,6 meses e não houve recorrência da doença original nesse período. O procedimento melhorou a acuidade visual com melhor correção de 20/36 (LogMar 0,250 para 20/24 (LogMar 0,076 com p<0,001. Em relação as mudanças refracionais não houve significância (p=0,232 sendo o equivalente esférico pré-operatório de - 0,36 ± 2,28DE e pós-operatório de -0,71 ± 2,26DE. As

  3. CVD calibration light systems specifications. Rev. 0

    International Nuclear Information System (INIS)

    Mcllwain, A. K.

    1992-04-01

    Two prototype Cerenkov Viewing Device Calibration Light systems for the Mark IV CVD have been fabricated. They consist of a maintenance unit that will be used by the IAEA maintenance staff and a field unit that will be used by IAEA inspectors. More detailed information on the design of the calibration units can be obtained from the document SSP-39 and additional information on the Mark IV CVD can be obtained from the operating manual published as Canadian Safeguards Support Program document CSSP 6. The specifications refer to the prototype units which will be demonstrated to the IAEA in 1992 May. Based upon the feedback from the IAEA, the instruments will be changed in the final production models to provide devices that more closely satisfy the needs of the end users

  4. Recent results with CVD diamond trackers

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; White, C.; Ziock, H.; Zoeller, M

    1999-08-01

    We present recent results on the use of Chemical Vapor Deposition (CVD) diamond microstrip detectors for charged particle tracking. A series of detectors was fabricated using 1 x 1 cm{sup 2} diamonds. Good signal-to-noise ratios were observed using both slow and fast readout electronics. For slow readout electronics, 2 {mu}s shaping time, the most probable signal-to-noise ratio was 50 to 1. For fast readout electronics, 25 ns peaking time, the most probable signal-to-noise ratio was 7 to 1. Using the first 2 x 4 cm{sup 2} diamond from a production CVD reactor with slow readout electronics, the most probable signal-to-noise ratio was 23 to 1. The spatial resolution achieved for the detectors was consistent with the digital resolution expected from the detector pitch.

  5. Recent results with CVD diamond trackers

    CERN Document Server

    Adam, W; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Runólfsson, O; Russ, J; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trawick, M L; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; White, C; Ziock, H J; Zöller, M

    1999-01-01

    We present recent results on the use of chemical vapor deposition (CVD) diamond microstrip detectors for charged particle tracking. A series of detectors was fabricated using 1*1 cm/sup 2/ diamonds. Good signal-to-noise ratios were observed using both slow and fast readout electronics. For slow readout electronics, 2 mu s shaping time, the most probable signal-to-noise ratio was 50 to 1. For fast readout electronics, 25 ns peaking time, the most probable signal-to-noise ratio was 7 to 1. Using the first 2*4 cm/sup 2/ diamond from a production CVD reactor with slow readout electronics, the most probable signal-to-noise ratio was 23 to 1. The spatial resolution achieved for the detectors was consistent with the digital resolution expected from the detector pitch. (6 refs).

  6. Desarrollo de un sistema de control numérico computarizado de tres ejes (X, Y, Z) y eje de giro, para una máquina de perforado de diamante por láser

    OpenAIRE

    Otálora Lozano, Jorge Humberto

    2016-01-01

    Aquest treball es realitza amb la col·laboració d'una empresa dedicada al disseny i fabricació d'eines per a la indústria productora de cable elèctric. A causa de manca de maquinària per al perforat de diamant, aquesta empresa presenta dificultats de producció, però, té a la seva disposició diferents equips que serien aptes per al perforat del diamant però que no pot utilitzar ja que el seu control i configuració no és correcta. Es decideix realitzar el present treball per m...

  7. Ballistic Josephson junctions based on CVD graphene

    Science.gov (United States)

    Li, Tianyi; Gallop, John; Hao, Ling; Romans, Edward

    2018-04-01

    Josephson junctions with graphene as the weak link between superconductors have been intensely studied in recent years, with respect to both fundamental physics and potential applications. However, most of the previous work was based on mechanically exfoliated graphene, which is not compatible with wafer-scale production. To overcome this limitation, we have used graphene grown by chemical vapour deposition (CVD) as the weak link of Josephson junctions. We demonstrate that very short, wide CVD-graphene-based Josephson junctions with Nb electrodes can work without any undesirable hysteresis in their electrical characteristics from 1.5 K down to a base temperature of 320 mK, and their gate-tuneable critical current shows an ideal Fraunhofer-like interference pattern in a perpendicular magnetic field. Furthermore, for our shortest junctions (50 nm in length), we find that the normal state resistance oscillates with the gate voltage, consistent with the junctions being in the ballistic regime, a feature not previously observed in CVD-graphene-based Josephson junctions.

  8. Undoped CVD diamond films for electrochemical applications

    International Nuclear Information System (INIS)

    Mosinska, Lidia; Fabisiak, Kazimierz; Paprocki, Kazimierz; Kowalska, Magdalena; Popielarski, Pawel; Szybowicz, Miroslaw

    2013-01-01

    By using different deposition conditions, the CVD diamond films with different qualities and orientation were grown by the hot-filament CVD technique. The object of this article is to summarize and discuss relation between structural, physical and electrochemical properties of different diamond electrodes. The physical properties of the Hot Filament CVD microcrystalline diamond films are analyzed by scanning electron microscopy and Raman spectroscopy. In presented studies two different electrodes were used of the diamond grain sizes around 200 nm and 10 μm, as it was estimated from SEM picture. The diamond layers quality was checked on basis of FWHM (Full width at Half Maximum) of 1332 cm −1 diamond Raman peak. The ratio of sp 3 /sp 2 carbon bonds was determined by 1550 cm −1 G band and 1350 cm −1 D band in the Raman spectrum. The electrochemical properties were analyzed using (CV) cyclic voltammetry measurements in aqueous solutions. The sensitivity of undoped diamond electrodes depends strongly on diamond film quality and concentration of amorphous carbon phase in the diamond layer

  9. Effects of Different Systemic Insecticides in Carotenoid Content, Antibacterial Activity and Morphological Characteristics of Tomato (Solanum lycopersicum var Diamante

    Directory of Open Access Journals (Sweden)

    LEXTER R. NATIVIDAD

    2014-02-01

    Full Text Available This study aimed to determine the effects of different systemic insecticides in tomato (Lycopersicon esculentum var. Diamante. The study also assessed different systemic insecticides used in other plants in their effectiveness and suitability to tomato by evaluating the carotenoid content and antibacterial activity of each insecticide. Morphological characteristics such as the weight, the number and the circumference of tomato fruits and the height of the plant were also observed. Moreover, the cost effectiveness was computed. Treatments were designated as follows: Treatment 1- plants sprayed with active ingredient (a.i. cartap hydrochloride; Treatment 2 - plants sprayed with a.i. indoxacarb; Treatment 3- plants sprayed with a.i. chlorantraniliprole and thiamethoxam; Treatment 4 - plants sprayed with a.i. dinotefuran (positive control; and Treatment 5 - no insecticide applied. The experimental design used was Randomized Complete Block Design (RCBD with three replications. The first three systemic insecticides with such active ingredient were not yet registered for tomato plant. Statistical analyses show that there were no significant differences among the weight, the number and the circumference of tomato fruits and the height of the plant for each treatment. Results showed that treatments 1, 2, 3, 4 and 5 extracts have 49.74, 44.16, 48.19, 52.57 and 50.60 μg/g of total carotenoids (TC, respectively. Statistical analysis shows that there no significant differences in the TC content of each treatment. The antibacterial activity of each plant sample showed no significant differences among treatments. Thin layer chromatographic analysis revealed that there were equal numbers of spots for all the plant samples.The study concluded that systemic insecticide with a.i. cartap hydrochloride be introduced to the farmers as insecticide for tomato plant since it shows comparable effect with the registered insecticide (T4 based on the morphological

  10. Middlebrow modernism in film(theory: Visconti’s Senso (1954 vis-à-vis Diamant-Berger’s La madone des sleepings (1955

    Directory of Open Access Journals (Sweden)

    Peter Verstraten

    2015-06-01

    Full Text Available By reflecting upon the travelling concept of the (film ‘auteur’, the first part of the article argues that Modernism manifests itself differently in cinema studies than in literary studies. Whereas the literary canon is constituted by excluding anything connoting conventional reading matter, a ‘pantheon’ of great directors exhibits a ‘peaceful coexistence’ between popular films and art cinema. The second part of the article addresses the shift in Rudolf Arnheim’s film theory from die-hard Modernist in the 1930s to middlebrow Modernist in the 1950s in a period when Henri Diamant-Berger made an adaptation of Maurice Dekobra’s La madone des sleepings. Concerned with a ‘psychology of art’, Arnheim is to claim a ‘stylized simplicity’ which in the end is better represented by Luchino Visconti’s colourful but nonetheless ‘sophisticated’ melodrama Senso than by Diamant-Berger’s too modest picture. Visconti’s film gives body to the idea of film as a ‘pan-art’, which implies that it is characteristic of cinema to incorporate influences from other art films but also to parasite upon sentimentalism and (high emotion.

  11. An assessment of radiotherapy dosimeters based on CVD grown diamond

    International Nuclear Information System (INIS)

    Ramkumar, S.; Buttar, C.M.; Conway, J.; Whitehead, A.J.; Sussman, R.S.; Hill, G.; Walker, S.

    2001-01-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after ∼6 Gy. The diamond devices of CVD2 type had a response at low fields ( 1162.8 V/cm), the CVD2-type devices showed polarisation and dose-rate dependence. The sensitivity of the CVD diamond devices varied between 82 and 1300 nC/Gy depending upon the sample type and the applied voltage. The sensitivity of CVD diamond devices was significantly higher than that of natural diamond and silicon dosimeters. The results suggest that CVD diamond devices can be fabricated for successful use in radiotherapy applications

  12. Comparative evaluation of CVD diamond technologies

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, T.R. [General Electric Corporate Research & Development Center, Schenectady, NY (United States)

    1993-01-01

    Chemical vapor deposition (CVD) of diamonds occurs from hydrogen-hydrocarbon gas mixtures in the presence of atomic hydrogen at subatmospheric pressures. Most CVD methods are based on different means of generating and transporting atomic hydrogen in a particular system. Evaluation of these different techniques involves their capital costs, material costs, energy costs, labor costs and the type and quality of diamond that they produce. Currently, there is no universal agreement on which is the best technique and technique selection has been largely driven by the professional background of the user as well as the particular application of interest. This article discusses the criteria for evaluating a process for low-pressure deposition of diamond. Next, a brief history of low-pressure diamond synthesis is reviewed. Several specific processes are addressed, including the hot filament process, hot filament electron-assisted chemical vapor deposition, and plasma generation of atomic hydrogen by glow discharge, microwave discharge, low pressure radio frequency discharge, high pressure DC discharge, high pressure microwave discharge jets, high pressure RF discharge, and high and low pressure flames. Other types of diamond deposition methods are also evaluated. 101 refs., 15 figs.

  13. Development of CVD diamond radiation detectors

    CERN Document Server

    Adam, W; Berdermann, E; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fisch, D; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Meier, D; Mishina, M; Le Normand, F; Pan, L S; Pernegger, H; Pernicka, Manfred; Pirollo, S; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zoeller, M M

    1998-01-01

    Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are presented in terms of collection distance, $d=\\mu E \\tau$, the average distance electron-hole pairs move apart under the influence of an electric field, where $\\mu$ is the sum of carrier mo bilities, $E$ is the applied electric field, and $\\tau$ is the mobility weighted carrier lifetime. Over the last two years the collection distance increased from $\\sim$ 75 $\\mu$m to over 200 $\\mu$ m. With this high quality CVD diamond a series of micro-strip and pixel particle detectors have been constructed. These devices were tested to determine their position resolution and signal to n oise performance. Diamond detectors w...

  14. TSC response of irradiated CVD diamond films

    CERN Document Server

    Borchi, E; Bucciolini, M; Guasti, A; Mazzocchi, S; Pirollo, S; Sciortino, S

    1999-01-01

    CVD diamond films have been irradiated with electrons, sup 6 sup 0 Co photons and protons in order to study the dose response to exposure to different particles and energies and to investigate linearity with dose. The Thermally Stimulated Current (TSC) has been studied as a function of the dose delivered to polymethilmetacrilate (PMMA) in the range from 1 to 12 Gy with 20 MeV electrons from a linear accelerator. The TSC spectrum has revealed the presence of two components with peak temperatures of about 470 and 520 K, corresponding to levels lying in the diamond band gap with activation energies of the order of 0.7 - 1 eV. After the subtraction of the exponential background the charge emitted during the heating scan has been evaluated and has been found to depend linearly on the dose. The thermally emitted charge of the CVD diamond films has also been studied using different particles. The samples have been irradiated with the same PMMA dose of about 2 Gy with 6 and 20 MeV electrons from a Linac, sup 6 sup 0 ...

  15. High collection efficiency CVD diamond alpha detectors

    International Nuclear Information System (INIS)

    Bergonzo, P.; Foulon, F.; Marshall, R.D.; Jany, C.; Brambilla, A.; McKeag, R.D.; Jackman, R.B.

    1998-01-01

    Advances in Chemical Vapor Deposited (CVD) diamond have enabled the routine use of this material for sensor device fabrication, allowing exploitation of its unique combination of physical properties (low temperature susceptibility (> 500 C), high resistance to radiation damage (> 100 Mrad) and to corrosive media). A consequence of CVD diamond growth on silicon is the formation of polycrystalline films which has a profound influence on the physical and electronic properties with respect to those measured on monocrystalline diamond. The authors report the optimization of physical and geometrical device parameters for radiation detection in the counting mode. Sandwich and co-planar electrode geometries are tested and their performances evaluated with regard to the nature of the field profile and drift distances inherent in such devices. The carrier drift length before trapping was measured under alpha particles and values as high as 40% of the overall film thickness are reported. Further, by optimizing the device geometry, they show that a gain in collection efficiency, defined as the induced charge divided by the deposited charge within the material, can be achieved even though lower bias values are used

  16. A CVD diamond beam telescope for charged particle tracking

    CERN Document Server

    Adam, W; Bergonzo, P; de Boer, Wim; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Dulinski, W; Doroshenko, J; Doucet, M; van Eijk, B; Fallou, A; Fischer, P; Fizzotti, F; Kania, D R; Gan, K K; Grigoriev, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kaplon, J; Kass, R; Keil, M; Knöpfle, K T; Koeth, T W; Krammer, Manfred; Meuser, S; Lo Giudice, A; MacLynne, L; Manfredotti, C; Meier, D; Menichelli, D; Mishina, M; Moroni, L; Noomen, J; Oh, A; Pan, L S; Pernicka, Manfred; Perera, L P; Riester, J L; Roe, S; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Trischuk, W; Tromson, D; Vittone, E; Weilhammer, Peter; Wermes, N; Wetstein, M; Zeuner, W; Zöller, M

    2002-01-01

    CVD diamond is a radiation hard sensor material which may be used for charged particle tracking near the interaction region in experiments at high luminosity colliders. The goal of the work described here is to investigate the use of several detector planes made of CVD diamond strip sensors for charged particle tracking. Towards this end a tracking telescope composed entirely of CVD diamond planes has been constructed. The telescope was tested in muon beams and its tracking capability has been investigated.

  17. Experiment and equipment of depositing diamond films with CVD system

    International Nuclear Information System (INIS)

    Xie Erqing; Song Chang'an

    2002-01-01

    CVD (chemical vapor deposition) emerged in recent years is a new technique for thin film deposition, which play a key role in development of modern physics. It is important to predominate the principle and technology of CVD for studying modern physics. In this paper, a suit of CVD experimental equipment for teaching in college physics is presented, which has simple design and low cost. The good result was gained in past teaching practices

  18. New developments in CVD diamond for detector applications

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; de Boer, W.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Dulinski, W.; Doroshenko, J.; van Eijk, B.; Fallou, A.; Fischer, P.; Fizzotti, F.; Furetta, C.; Gan, K. K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Kass, R.; Keil, M.; Knoepfle, K. T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pernicka, M.; Perera, L.; Potenza, R.; Riester, J. L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.

    Chemical Vapor Deposition (CVD) diamond has been discussed extensively as an alternative sensor material for use very close to the interaction region of the LHC and other machines where extreme radiation conditions exist. During the last seven years the RD42 collaboration has developed diamond detectors and tested them with LHC electronics towards the end of creating a device usable by experiments. The most recent results of this work are presented. Recently, a new form of CVD diamond has been developed: single crystal CVD diamond which resolves many of the issues associated with poly-crystalline CVD material. The first tests of this material are also presented.

  19. New developments in CVD diamond for detector applications

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W. [HEPHY, Vienna (Austria); Berdermann, E. [GSI, Darmstadt (Germany); Bergonzo, P.; Brambilla, A. [LETI/DEIN/SPE/CEA Saclay (France); Boer, W. de [Universitaet Karlsruhe, Karlsruhe (Germany); Bogani, F. [LENS, Florence (Italy); Borchi, E.; Bruzzi, M. [University of Florence (Italy); Colledani, C.; Dulinski, W. [LEPSI, IN2P3/CNRS-ULP, Strasbourg (France); Conway, J.; Doroshenko, J. [Rutgers University, Piscataway (United States); D' Angelo, P.; Furetta, C. [INFN, Milano (Italy); Dabrowski, W. [UMM, Cracow (Poland); Delpierre, P.; Fallou, A. [CPPM, Marseille (France); Eijk, B. van [NIKHEF, Amsterdam (Netherlands); Fischer, P. [Universitaet Bonn, Bonn (Germany); Fizzotti, F. [University of Torino (Italy); Gan, K.K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Kass, R.; Keil, M.; Knoepfle, K.T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pernicka, M.; Perera, L.; Potenza, R.; Riester, J.L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.

    2004-07-01

    Chemical Vapor Deposition (CVD) diamond has been discussed extensively as an alternative sensor material for use very close to the interaction region of the LHC and other machines where extreme radiation conditions exist. During the last seven years the RD42 collaboration has developed diamond detectors and tested them with LHC electronics towards the end of creating a device usable by experiments. The most recent results of this work are presented. Recently, a new form of CVD diamond has been developed: single crystal CVD diamond which resolves many of the issues associated with poly-crystalline CVD material. The first tests of this material are also presented. (orig.)

  20. New developments in CVD diamond for detector applications

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Brambilla, A.; Boer, W. de; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Dulinski, W.; Conway, J.; Doroshenko, J.; D'Angelo, P.; Furetta, C.; Dabrowski, W.; Delpierre, P.; Fallou, A.; Eijk, B. van; Fischer, P.; Fizzotti, F.; Gan, K.K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Kass, R.; Keil, M.; Knoepfle, K.T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pernicka, M.; Perera, L.; Potenza, R.; Riester, J.L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.

    2004-01-01

    Chemical Vapor Deposition (CVD) diamond has been discussed extensively as an alternative sensor material for use very close to the interaction region of the LHC and other machines where extreme radiation conditions exist. During the last seven years the RD42 collaboration has developed diamond detectors and tested them with LHC electronics towards the end of creating a device usable by experiments. The most recent results of this work are presented. Recently, a new form of CVD diamond has been developed: single crystal CVD diamond which resolves many of the issues associated with poly-crystalline CVD material. The first tests of this material are also presented. (orig.)

  1. Application of CVD diamond film for radiation detection

    International Nuclear Information System (INIS)

    Zhou Haiyang; Zhu Xiaodong; Zhan Rujuan

    2005-01-01

    With the development of diamond synthesis at low pressure, the CVD diamond properties including electronic characteristics have improved continuously. Now the fabrication of electronic devices based on the CVD diamond has been one of hot research subjects in this field. Due to many unique advantages, such as high signal-noise ratio, fast time response, and normal output in extremely harsh surrounding, the CVD diamond radiation detector has attracted more and more interest. In this paper, we have reviewed the development and status of the CVD diamond radiation detector. The prospect of this detector is described. (authors)

  2. CVD diamond detectors for ionizing radiation

    CERN Document Server

    Friedl, M; Bauer, C; Berfermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

    1999-01-01

    In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2*4 cm/sup 2/ have been grown and refined for better charge collection properties, which are measured with a beta source or in a test beam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5*10/sup 15/ cm/sup -2/ to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics. (16 refs).

  3. CVD diamond sensors for charged particle detection

    CERN Document Server

    Krammer, Manfred; Berdermann, E; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Dencuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zöller, M

    2001-01-01

    CVD diamond material was used to build position-sensitive detectors for single-charged particles to be employed in high-intensity physics experiments. To obtain position information, metal contacts shaped as strips or pixels are applied to the detector surface for one- or two- dimensional coordinate measurement. Strip detectors 2*4 cm/sup 2/ in size with a strip distance of 50 mu m were tested. Pixel detectors of various pixel sizes were bump bonded to electronics chips and investigated. A key issue for the use of these sensors in high intensity experiments is the radiation hardness. Several irradiation experiments were carried out with pions, protons and neutrons exceeding a fluence of 10/sup 15/ particles/cm/sup 2/. The paper presents an overview of the results obtained with strip and pixel detectors in high-energy test beams and summarises the irradiation studies. (8 refs).

  4. CVD diamond detectors for ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, M. E-mail: markus.friedl@cern.ch; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M

    1999-10-01

    In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2x4 cm{sup 2} have been grown and refined for better charge collection properties, which are measured with a {beta} source or in a test beam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5x10{sup 15} cm{sup -2} to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics. (author)

  5. CVD diamond detectors for ionizing radiation

    Science.gov (United States)

    Friedl, M.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P. F.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

    1999-10-01

    In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2×4 cm2 have been grown and refined for better charge collection properties, which are measured with a β source or in a testbeam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5×10 15 cm-2 to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics.

  6. Premature menopause linked to CVD and osteoporosis.

    Science.gov (United States)

    Park, Claire; Overton, Caroline

    2010-03-01

    Premature menopause affects 1% of women under the age of 40, the usual age of the menopause is 51. Most women will present with irregular periods or no periods at all with or without climacteric symptoms. Around 10% of women present with primary amenorrhoea. A careful history and examination are required. It is important to ask specifically about previous chemotherapy or radiotherapy and to look for signs of androgen excess e.g. polycystic ovarian syndrome, adrenal problems e.g. galactorrhoea and thyroid goitres. Once pregnancy has been excluded, a progestagen challenge test can be performed in primary care. Norethisterone 5 mg tds po for ten days or alternatively medroxyprogesterone acetate 10 mg daily for ten days is prescribed. A withdrawal bleed within a few days of stopping the norethisterone indicates the presence of oestrogen and bleeding more than a few drops is considered a positive withdrawal bleed. The absence of a bleed indicates low levels of oestrogen, putting the woman at risk of CVD and osteoporosis. FSH levels above 30 IU/l are an indicator that the ovaries are failing and the menopause is approaching or has occurred. It should be remembered that FSH levels fluctuate during the month and from one month to the next, so a minimum of two measurements should be made at least four to six weeks apart. The presence of a bleed should not exclude premature menopause as part of the differential diagnosis as there can be varying and unpredictable ovarian function remaining. The progestagen challenge test should not be used alone, but in conjunction with FSH, LH and oestradiol. There is no treatment for premature menopause. Women desiring pregnancy should be referred to a fertility clinic and discussion of egg donation. Women not wishing to become pregnant should be prescribed HRT until the age of 50 to control symptoms of oestrogen deficiency and reduce the risks of osteoporosis and CVD.

  7. Diamond radiation detectors II. CVD diamond development for radiation detectors

    International Nuclear Information System (INIS)

    Kania, D.R.

    1997-01-01

    Interest in radiation detectors has supplied some of the impetus for improving the electronic properties of CVD diamond. In the present discussion, we will restrict our attention to polycrystalhne CVD material. We will focus on the evolution of these materials over the past decade and the correlation of detector performance with other properties of the material

  8. Lipids, atherosclerosis and CVD risk: is CRP an innocent bystander?

    DEFF Research Database (Denmark)

    Nordestgaard, B G; Zacho, J

    2009-01-01

    AIM: To evaluate recent human studies with respect to the interpretation of whether elevated plasma levels of C-reactive protein (CRP) cause cardiovascular disease (CVD), or whether elevated CRP levels more likely is an innocent bystander. DATA SYNTHESIS: Elevated CRP concentrations...... and vulnerability of atherosclerotic plaques, and thus simply an innocent bystander in CVD....

  9. Micro-strip sensors based on CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D. E-mail: dirk.meier@cern.ch; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M

    2000-10-11

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  10. Micro-strip sensors based on CVD Diamond

    CERN Document Server

    Adam, W; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Krammer, Manfred; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S R; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zoeller, M M

    2000-01-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  11. Micro-strip sensors based on CVD diamond

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.

    2000-01-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation

  12. Micro-strip sensors based on CVD diamond

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L. S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J. L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; RD42 Collaboration

    2000-10-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  13. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  14. CVD diamond deposition onto dental burs

    International Nuclear Information System (INIS)

    Ali, N.; Sein, H.

    2001-01-01

    A hot-filament chemical vapor deposition (HFCVD) system has been modified to enable non-planar substrates, such as metallic wires and dental burs, to be uniformly coated with thin polycrystalline diamond films. Initially, diamond deposition was carried out on titanium and tantalum wires in order to test and optimize the system. High growth rates of the order of approx. 8 /hr were obtained when depositing diamond on titanium wires using the vertical filament arrangement. However, lower growth rates of the order of 4-5meu m/hr were obtained with diamond deposition on tantalum wires. To extend the work towards a practical biomedical application tungsten carbide dental burs were coated with diamond films. The as-grown films were found to be polycrystalline and uniform over the cutting tip. Finally, the costs relating to diamond CVD onto dental burs have been presented in this paper. The costs relating to coating different number of burs at a time and the effect of film thickness on costs have been included in this investigation. (author)

  15. CVD diamond substrates for electronic devices

    International Nuclear Information System (INIS)

    Holzer, H.

    1996-03-01

    In this study the applicability of chemical vapor deposition (CVD) diamond as a material for heat spreaders was investigated. Economical evaluations on the production of heat spreaders were also performed. For the diamond synthesis the hot-filament and microwave method were used respectively. The deposition parameters were varied in a way that free standing diamond layers with a thickness of 80 to 750 microns and different qualities were obtained. The influence of the deposition parameters on the relevant film properties was investigated and discussed. With both the hot-filament and microwave method it was possible to deposit diamond layers having a thermal conductivity exceeding 1200 W/mK and therefore to reach the quality level for commercial uses. The electrical resistivity was greater than 10 12 Ωcm. The investigation of the optical properties was done by Raman-, IR- and cathodoluminescence spectroscopy. Because of future applications of diamond-aluminium nitride composites as highly efficient heat spreaders diamond deposition an AIN was investigated. An improved substrate pretreatment prior to diamond deposition showed promising results for better performance of such composite heat spreaders. Both free standing layers and diamond-AIN composites could be cut by a CO2 Laser in Order to get an exact size geometry. A reduction of the diamond surface roughness was achieved by etching with manganese powder or cerium. (author)

  16. CVD-Graphene-Based Flexible, Thermoelectrochromic Sensor

    Directory of Open Access Journals (Sweden)

    Adam Januszko

    2017-01-01

    Full Text Available The main idea behind this work was demonstrated in a form of a new thermoelectrochromic sensor on a flexible substrate using graphene as an electrically reconfigurable thermal medium (TEChrom™. Our approach relies on electromodulation of thermal properties of graphene on poly(ethylene terephthalate (PET via mechanical destruction of a graphene layer. Graphene applied in this work was obtained by chemical vapor deposition (CVD technique on copper substrate and characterized by Raman and scanning tunneling spectroscopy. Electrical parameters of graphene were evaluated by the van der Pauw method on the transferred graphene layers onto SiO2 substrates by electrochemical delamination method. Two configurations of architecture of sensors, without and with the thermochromic layer, were investigated, taking into account the increase of voltage from 0 to 50 V and were observed by thermographic camera to define heat energy. Current-voltage characteristics obtained for the sensor with damaged graphene layer are linear, and the resistivity is independent from the current applied. The device investigated under 1000 W/m2 exhibited rise of resistivity along with increased temperature. Flexible thermoelectrochromic device with graphene presented here can be widely used as a sensor for both the military and civil monitoring.

  17. En usleben diamant

    DEFF Research Database (Denmark)

    Jakobsen, Helle Nordentoft; Guldmann Jensen, Mads Emil

    2017-01-01

    I denne artikel udforsker vi, hvordan video bidrager til at udvikle masterstude-rendes kritisk refleksive blik på egen vejledningspraksis. Omdrejningspunktet er det didaktiske og dialogiske arbejde med video på modul 3, Master i Vejled-ning, DPU. Artiklen er baseret på de studerendes individuelle...

  18. Selection and integration of a network of parallel processors in the real time acquisition system of the 4π DIAMANT multidetector: modeling, realization and evaluation of the software installed on this network

    International Nuclear Information System (INIS)

    Guirande, F.

    1997-01-01

    The increase in sensitivity of 4π arrays such as EUROBALL or DIAMANT has led to an increase in the data flow rate into the data acquisition system. If at the electronic level, the data flow has been distributed onto several data acquisition buses, it is necessary in the data processing system to increase the processing power. This work regards the modelling and implementation of the software allocated onto an architecture of parallel processors. Object analysis and formal methods were used, benchmark and evolution in the future of this architecture are presented. The thesis consists of two parts. Part A, devoted to 'Nuclear Spectroscopy with 4 π multidetectors', contains a first chapter entitled 'The Physics of 4π multidetectors' and a second chapter entitled 'Integral architecture of 4π multidetectors'. Part B, devoted to 'Parallel acquisition system of DIAMANT' contains three chapters entitled 'Material architecture', 'Software architecture' and 'Validation and Performances'. Four appendices and a term glossary close this work. (author)

  19. Evaluación de la resistencia a la corrosión erosión de recubrimientos de níquel modificados con nanopartículas de diamante

    Directory of Open Access Journals (Sweden)

    Luz Amira Torres Medina

    2010-01-01

    Full Text Available La incorporación de nanopartículas de carburos, nitruros, óxidos o diamante en una matriz metálica, generalmente muestran mejoras en la dureza, en la resistencia al desgaste y a la corrosión, comparado con un recubrimiento del metal puro. Estos recubrimientos compuestos se pueden obtener mediante la técnica de electrodeposición, logrando economía y calidad en los depósitos. Los recubrimientos de níquel modificados con nanopartículas de diamante (Ni-D, fueron aplicados sobre un acero AISI SAE 1016 mediante la técnica de electrodeposición desde una solución típica Watts sin aditivos, que contiene nanopartículas de diamante. El efecto que ejercen algunas variables que intervienen en el proceso de electrodeposición como: densidad de corriente, velocidad de agitación y concentración de partículas en el baño, en la dureza y en la resistencia a la corrosión-erosión, se estudiaron mediante un diseño factorial completamente aleatorizado 2k. La resistencia a la corrosión- erosión se evaluó mediante el monitoreo del potencial de corrosión de las probetas con recubrimiento sometidas a un fluido corrosivo y abrasivo en movimiento. Los recubrimientos compuestos de Ni-D obtenidos presentan mejor resistencia a la corrosión-erosión que los recubrimientos de níquel puro. Los recubrimientos más resistentes a la corrosión-erosión fueron los obtenidos a 5 A/dm², 900 rpm y 10 g/L de diamante.

  20. Selection and integration of a network of parallel processors in the real time acquisition system of the 4{pi} DIAMANT multidetector: modeling, realization and evaluation of the software installed on this network; Choix et integration d`un reseau de processeurs paralleles dans le systeme d`acquisition temps reel du multidetecteur 4{pi} DIAMANT: modelisation, realisation et evaluation du logiciel implante sur ce reseau

    Energy Technology Data Exchange (ETDEWEB)

    Guirande, F. [Ecole Doctorale des Sciences Physiques et de l`Ingenieur, Bordeaux-1 Univ., 33 (France)

    1997-07-11

    The increase in sensitivity of 4{pi} arrays such as EUROBALL or DIAMANT has led to an increase in the data flow rate into the data acquisition system. If at the electronic level, the data flow has been distributed onto several data acquisition buses, it is necessary in the data processing system to increase the processing power. This work regards the modelling and implementation of the software allocated onto an architecture of parallel processors. Object analysis and formal methods were used, benchmark and evolution in the future of this architecture are presented. The thesis consists of two parts. Part A, devoted to `Nuclear Spectroscopy with 4 {pi} multidetectors`, contains a first chapter entitled `The Physics of 4{pi} multidetectors` and a second chapter entitled `Integral architecture of 4{pi} multidetectors`. Part B, devoted to `Parallel acquisition system of DIAMANT` contains three chapters entitled `Material architecture`, `Software architecture` and `Validation and Performances`. Four appendices and a term glossary close this work. (author) 58 refs.

  1. CVD refractory metals and alloys for space nuclear power application

    International Nuclear Information System (INIS)

    Yang, L.; Gulden, T.D.; Watson, J.F.

    1984-01-01

    CVD technology has made significant contributions to the development of space nuclear power systems during the period 1962 to 1972. For the in-core thermionic concept, CVD technology is essential to the fabrication of the tungsten electron emitter. For the liquid metal cooled fuel pin using uranium nitride as fuel and T-111 and Nb-1 Zr as cladding, a tungsten barrier possibly produced by CVD methods is essential to the fuel-cladding compatibility at the designed operating temperature. Space power reactors may use heat pipes to transfer heat from the reactor core to the conversion system. CVD technology has been used for fabricating the heat pipe used as cross-flow heat exchanger, including the built-in channels on the condenser wall for liquid lithium return. 28 references, 17 figures

  2. Investigation of defects in CVD diamond: Influence for radiotherapy applications

    International Nuclear Information System (INIS)

    Guerrero, M.J.; Tromson, D.; Bergonzo, P.; Barrett, R.

    2005-01-01

    In this study we present the potentialities of CVD diamond as an ionisation chamber for radiotherapy applications. Trapping levels present in CVD diamond are characterised using Thermally Stimulated Current (TSC) method with X-ray sources. The influence of the corresponding defects on the detector response is investigated and compared to those observed in natural diamond. Also, their spatial distribution across a large area polycrystalline diamond ionisation chamber is discussed. Results show the relative influence of two different populations of trapping levels in CVD diamond whose effect is crucial for radiotherapy applications. To partially overcome the defect detrimental effects, we propose to use CVD diamond ionisation chambers at moderate temperatures from 70 to 100 deg. C that could be provided by self heating of the device, for a dramatically improved stability and reproducibility

  3. The gate oxide integrity of CVD tungsten polycide

    International Nuclear Information System (INIS)

    Wu, N.W.; Su, W.D.; Chang, S.W.; Tseng, M.F.

    1988-01-01

    CVD tungsten polycide has been demonstrated as a good gate material in recent very large scale integration (VLSI) technology. CVD tungsten silicide offers advantages of low resistivity, high temperature stability and good step coverage. On the other hand, the polysilicon underlayer preserves most characteristics of the polysilicon gate and acts as a stress buffer layer to absorb part of the thermal stress origin from the large thermal expansion coefficient of tungsten silicide. Nevertheless, the gate oxide of CVD tungsten polycide is less stable or reliable than that of polysilicon gate. In this paper, the gate oxide integrity of CVD tungsten polycide with various thickness combinations and different thermal processes have been analyzed by several electrical measurements including breakdown yield, breakdown fluence, room temperature TDDB, I-V characteristics, electron traps and interface state density

  4. Verification of thermo-fluidic CVD reactor model

    International Nuclear Information System (INIS)

    Lisik, Z; Turczynski, M; Ruta, L; Raj, E

    2014-01-01

    Presented paper describes the numerical model of CVD (Chemical Vapour Deposition) reactor created in ANSYS CFX, whose main purpose is the evaluation of numerical approaches used to modelling of heat and mass transfer inside the reactor chamber. Verification of the worked out CVD model has been conducted with measurements under various thermal, pressure and gas flow rate conditions. Good agreement between experimental and numerical results confirms correctness of the elaborated model.

  5. Ion beam figuring of CVD silicon carbide mirrors

    Science.gov (United States)

    Gailly, P.; Collette, J.-P.; Fleury Frenette, K.; Jamar, C.

    2017-11-01

    Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in reason of its good behavior under polishing. The advantage of applying ion beam figuring (IBF) to CVD-SiC over other surface figure-improving techniques is discussed herein. The results of an IBF sequence performed at the Centre Spatial de Liège on a 100 mm CVD-SiC mirror are reported. The process allowed to reduce the mirror surface errors from 243 nm to 13 nm rms . Beside the surface figure, roughness is another critical feature to consider in order to preserve the optical quality of CVD-SiC . Thus, experiments focusing on the evolution of roughness were performed in various ion beam etching conditions. The roughness of samples etched at different depths down to 3 ≠m was determined with an optical profilometer. These measurements emphasize the importance of selecting the right combination of gas and beam energy to keep roughness at a low level. Kaufman-type ion sources are generally used to perform IBF but the performance of an end-Hall ion source in figuring CVD-SiC mirrors was also evaluated in this study. In order to do so, ion beam etching profiles obtained with the end-Hall source on CVD-SiC were measured and used as a basis for IBF simulations.

  6. Formigas (Hymenoptera: Formicidae Bioindicadoras de Degradação Ambiental em Poxoréu, Mato Grosso, Brasil

    Directory of Open Access Journals (Sweden)

    Wilian de Oliveira Rocha

    Full Text Available Este trabalho teve por objetivo avaliar as espécies de formigas que ocorrem em áreas degradadas pela mineração de diamantes, definindo as espécies bioindicadoras desta degradação. O estudo realizado entre junho de 2010 e abril de 2011, bimestralmente, em Poxoréu - MT, amostrou quatro ambientes: A1 – área degradada pela mineração; A2 – área com vegetação de cerrado antropizado recentemente; A3 – vegetação antropizada há cerca de 30 anos; A4 – área de cerrado preservado. Em cada ambiente, foram instaladas 11 armadilhas pitfall, equidistantes 15 metros, para a coleta de formigas durante 24 horas. Os indivíduos coletados foram levados ao Laboratório de Proteção Florestal/FENF/UFMT e triados para posterior identificação. As espécies bioindicadoras foram indicadas por meio de análises faunísticas. As espécies Camponotus (Myrmaphaenus sp.1 e Forelius brasiliensis podem ser consideradas bioindicadoras de degradação ambiental na área de garimpo de diamantes e antropização, enquanto Camponotus atriceps, Pachycondyla crassinoda e Paraponera clavata podem ser consideradas bioindicadoras de cerrado preservado.

  7. Le dépôt de diamant en couche mince et ses applications Thin-Layer Diamond Depositing and Its Applications

    Directory of Open Access Journals (Sweden)

    Bertrand A.

    2006-11-01

    Full Text Available Nous avons cherché à faire le point sur la fabrication de couches minces de diamant qui, après avoir été très étudiée aux États-Unis vers la fin des années 1950, a fait l'objet d'une percée technologique soviétique en 1977. Celle-ci utilise l'effet solvant de l'hydrogène mélangé à un peu de méthane. Transformé en hydrogène atomique par décharge électrique, il interdit le dépôt de graphite et par conséquent permet seulement celui du diamant. Ce résultat est riche d'applications prometteuses en mécanique, en optique, en électronique. . . et constitue un élément clé pour la recherche spatiale. Les Japonais ont mis cinq ans pour réagir et les Américains cinq autres années. Mais ces derniers espèrent refaire leur retard grâce au programme Diamond Technology Initiative établi dans le cadre de l'initiative de Défense Stratégique (Guerre des Étoiles. Les retombées de ces travaux devraient concerner l'industrie pétrolière (paliers, trépans, capteurs en milieu extrême. This article reviews the depositing of diamond thin layers. After much research had been done on this technique in the United States in the late 1950s, a technological breakthrough was made by the Soviets in 1977. This breakthrough uses the solventeffect of hydrogen mixed with a bit of methane. This is transformed into atomic hydrogen by an electric discharge, thus preventing graphite from being deposited and hence enabling only diamond to be deposited. This achievement has a wealth of promising applications in mechanics, optics, electronics, etc. It is also a key element for space research. The Japanese took five years to react and the Americans another five years. But these latter hope to make up for lost time with the Diamond Technology Initiativepromoted within the framework of the Strategic Defense Initiative ( star wars . The fallouts from this research should involve the petroleum industry (bearings, drill bits, sensors in extreme

  8. Low-temperature graphene synthesis using microwave plasma CVD

    International Nuclear Information System (INIS)

    Yamada, Takatoshi; Kim, Jaeho; Ishihara, Masatou; Hasegawa, Masataka

    2013-01-01

    The graphene chemical vapour deposition (CVD) technique at substrate temperatures around 300 °C by a microwave plasma sustained by surface waves (surface wave plasma chemical vapour deposition, SWP-CVD) is discussed. A low-temperature, large-area and high-deposition-rate CVD process for graphene films was developed. It was found from Raman spectra that the deposited films on copper (Cu) substrates consisted of high-quality graphene flakes. The fabricated graphene transparent conductive electrode showed uniform optical transmittance and sheet resistance, which suggests the possibility of graphene for practical electrical and optoelectronic applications. It is intriguing that graphene was successfully deposited on aluminium (Al) substrates, for which we did not expect the catalytic effect to decompose hydrocarbon and hydrogen molecules. We developed a roll-to-roll SWP-CVD system for continuous graphene film deposition towards industrial mass production. A pair of winder and unwinder systems of Cu film was installed in the plasma CVD apparatus. Uniform Raman spectra were confirmed over the whole width of 297 mm of Cu films. We successfully transferred the deposited graphene onto PET films, and confirmed a transmittance of about 95% and a sheet resistance of less than 7 × 10 5 Ω/sq.

  9. Low-temperature graphene synthesis using microwave plasma CVD

    Science.gov (United States)

    Yamada, Takatoshi; Kim, Jaeho; Ishihara, Masatou; Hasegawa, Masataka

    2013-02-01

    The graphene chemical vapour deposition (CVD) technique at substrate temperatures around 300 °C by a microwave plasma sustained by surface waves (surface wave plasma chemical vapour deposition, SWP-CVD) is discussed. A low-temperature, large-area and high-deposition-rate CVD process for graphene films was developed. It was found from Raman spectra that the deposited films on copper (Cu) substrates consisted of high-quality graphene flakes. The fabricated graphene transparent conductive electrode showed uniform optical transmittance and sheet resistance, which suggests the possibility of graphene for practical electrical and optoelectronic applications. It is intriguing that graphene was successfully deposited on aluminium (Al) substrates, for which we did not expect the catalytic effect to decompose hydrocarbon and hydrogen molecules. We developed a roll-to-roll SWP-CVD system for continuous graphene film deposition towards industrial mass production. A pair of winder and unwinder systems of Cu film was installed in the plasma CVD apparatus. Uniform Raman spectra were confirmed over the whole width of 297 mm of Cu films. We successfully transferred the deposited graphene onto PET films, and confirmed a transmittance of about 95% and a sheet resistance of less than 7 × 105 Ω/sq.

  10. Evaluation of CVD silicon carbide for synchrotron radiation mirrors

    International Nuclear Information System (INIS)

    Takacs, P.Z.

    1981-07-01

    Chemical vapor deposited silicon carbide (CVD SiC) is a recent addition to the list of materials suitable for use in the harsh environment of synchrotron radiation (SR) beam lines. SR mirrors for use at normal incidence must be ultrahigh vacuum compatible, must withstand intense x-ray irradiation without surface damage, must be capable of being polished to an extremely smooth surface finish, and must maintain surface figure under thermal loading. CVD SiC exceeds the performance of conventional optical materials in all these areas. It is, however, a relatively new optical material. Few manufacturers have experience in producing optical quality material, and few opticians have experience in figuring and polishing the material. The CVD material occurs in a variety of forms, sensitively dependent upon reaction chamber production conditions. We are evaluating samples of CVD SiC obtained commercially from various manufacturers, representing a range of deposition conditions, to determine which types of CVD material are most suitable for superpolishing. At the time of this writing, samples are being polished by several commercial vendors and surface finish characteristics are being evaluated by various analytical methods

  11. Test of radiation hardness of pcCVD detectors

    Energy Technology Data Exchange (ETDEWEB)

    Schlemme, Steffen [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Enders, Joachim [Technische Universitaet Darmstadt (Germany); Figuera, P.; Salamone, S. [LNS-INFN Catania (Italy); Fruehauf, J.; Kis, Mladen; Kratz, A.; Kurz, N.; Loechner, S.; Nociforo, Chiara; Schirru, Fabio; Szczepanczyk, B.; Traeger, M.; Visinka, R. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Musumarra, A. [LNS-INFN Catania (Italy); University of Catania (Italy)

    2016-07-01

    The new in-flight separator Super-FRS is under construction at the Facility for Antiproton and Ion Research (FAIR, Darmstadt). Ion rates up to 3 x 10{sup 11} {sup 238}U/spill demand an adaption of detectors to a high radiation environment. A test experiment to investigate the radiation hardness of polycrystalline diamond detectors (pcCVD) was performed at the LNS-INFN in Catania using a {sup 12}C beam at 62 MeV/u and intensities of up to 1.5 pnA. The setup consisted of pcCVD strip detectors to measure the beam profile, a single crystal diamond detector to calibrate the ionisation chamber working in current mode as a beam intensity monitor and a pcCVD sample to be irradiated. The IC used was designed for FAIR and showed a stable counting rate allowing us to calibrate and perform beam intensity measurements with it. The total measured counts on the sample were 8.25 x 10{sup 11} counts/mm{sup 2} over a period of 60 hours. Digital waveforms of the pcCVD signals were taken with an oscilloscope and analysed. The results showed no change of the pcCVD signal properties during the entire irradiation.

  12. ESTUDIO INTRAPAÍSES DE LA COMPETITIVIDAD GLOBAL DESDE EL ENFOQUE DEL DOBLE DIAMANTE PARA PUERTO RICO, COSTA RICA Y SINGAPUR

    Directory of Open Access Journals (Sweden)

    Castro-Gonzáles, Segundo

    2014-09-01

    Full Text Available Muchos investigadores y economistas han argumentado que los estudios de competitividad del WEF e IMD muestran limitaciones en pequeñas economías,más aún cuando estas tienen características distintas. El objetivo de esta investigación es estudiar la competitividad de 3 peque˜nas economías: Puerto Rico, Costa Rica y Singapur. El modelo del doble-diamante de competitividad resulta útil a la hora de llevar a cabo esta tarea. La información procede de organismos internacionales. Los resultados muestran que Singapur goza de un mayor nivel de competitividad global comparado con Puerto Rico y Costa Rica. Concluimos que Puerto Rico y Costa Rica lucen equilibrados en competitividad, porque internacionalmente Puerto Rico aventaja a Costa Rica en 3 determinantes: condiciones de factores, condiciones de la demanda e industrias relacionadas y de apoyo; mientras que localmente Costa Rica es más competitivo que Puerto Rico en 3 factores domésticos: condiciones de factores, condiciones de demanda y estrategia de las firmas.

  13. Adhesion of non-selective CVD tungsten to silicon dioxide

    International Nuclear Information System (INIS)

    Woodruff, D.W.; Wilson, R.H.; Sanchez-Martinez, R.A.

    1986-01-01

    Adhesion of non-selective, CVD tungsten to silicon dioxide is a critical issue in the development of tungsten as a metalization for VLSI circuitry. Without special adhesion promoters, tungsten deposited from WF/sub 6/ and H/sub 2/ has typically failed a standard tape test over all types of silicon oxides and nitrides. The reasons for failure of thin films, and CVD tungsten in particular are explored along with standard techniques for improving adhesion of thin films. Experiments are reported which include a number of sputtered metals as adhesion promoters, as well as chemical and plasma treatment of the oxide surface. Sputtered molybdenum is clearly the superior adhesion promoting layer from these tests. Traditional adhesion layers such as chromium or titanium failed as adhesion layers for CVD tungsten possibly due to chemical reactions between the WF/sub 6/ and Cr or Ti

  14. The formation of tritium permeation barriers by CVD

    International Nuclear Information System (INIS)

    Forcey, K.S.; Perujo, A.; Reiter, F.; Lolli-Ceroni, P.L.

    1993-01-01

    The effectiveness as permeation barriers of the following CVD coatings have been investigated: TiC (1 to 2 μm in thickness); a bi-layer of TiN on TiC (3 μm total thickness) and CVD Al 2 O 3 on a TiN/TiC bi-layer. The substrate materials were TZM (a Mo alloy) and 316L stainless steel in the form of discs of diameter 48 mm and thickness 0.1 or 1 mm. Permeation measurements were performed in the temperature range 515-742 K using deuterium at pressures in the range 1-50 kPa. CVD layers were shown to form reasonably effective permeation barriers. At a temperature of 673 K TiC is around 6000 times less permeable to deuterium than 316L stainless steel. (orig.)

  15. Graphene Synthesis by Plasma-Enhanced CVD Growth with Ethanol

    OpenAIRE

    Campo, T.; Cotto, M.; Márquez, F.; Elizalde, E.; Morant, C.

    2016-01-01

    A modified route to synthesize graphene flakes is proposed using the Chemical Vapor Deposition (CVD) technique, by using copper substrates as supports. The carbon source used was ethanol, the synthesis temperature was 950°C and the pressure was controlled along the whole process. In this CVD synthesis process the incorporation of the carbon source was produced at low pressure and 950°C inducing the appearance of a plasma blue flash inside the quartz tube. Apparently, the presence of this plas...

  16. Correlation of CVD Diamond Electron Emission with Film Properties

    Science.gov (United States)

    Bozeman, S. P.; Baumann, P. K.; Ward, B. L.; Nemanich, R. J.; Dreifus, D. L.

    1996-03-01

    Electron field emission from metals is affected by surface morphology and the properties of any dielectric coating. Recent results have demonstrated low field electron emission from p-type diamond, and photoemission measurements have identified surface treatments that result in a negative electron affinity (NEA). In this study, the field emission from diamond is correlated with surface treatment, surface roughness, and film properties (doping and defects). Electron emission measurements are reported on diamond films synthesized by plasma CVD. Ultraviolet photoemission spectroscopy indicates that the CVD films exhibit a NEA after exposure to hydrogen plasma. Field emission current-voltage measurements indicate "threshold voltages" ranging from approximately 20 to 100 V/micron.

  17. Radiation tolerance of CVD diamond detectors for pions and protons

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F. E-mail: f.hartjes@nikhef.nl; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M

    2002-01-11

    The paper gives new results on the radiation tolerance of CVD diamond for irradiation with 300 MeV/c pions and 24 GeV/c protons. The measured charge signal spectrum is compared at several irradiation levels with the spectrum calculated by a model. Irradiation by particles causes damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model show that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal.

  18. Radiation tolerance of CVD diamond detectors for pions and protons

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L. S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J. L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.

    2002-01-01

    The paper gives new results on the radiation tolerance of CVD diamond for irradiation with 300 MeV/ c pions and 24 GeV/ c protons. The measured charge signal spectrum is compared at several irradiation levels with the spectrum calculated by a model. Irradiation by particles causes damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model show that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal.

  19. Application of Cat-CVD for ULSI technology

    International Nuclear Information System (INIS)

    Akasaka, Yoichi

    2008-01-01

    The ULSI technology has been following Moore's law into the sub-100 nm era, although several challenging technical issues must be resolved. This paper describes possible application of Cat-CVD for ULSI technology beyond the 45 nm node. Especially, Cat-CVD SiN film for a transistor gate sidewall and/or a pre-metallic liner layer, and removal of photo resist (ash) by Cat-induced hydrogen atoms in the interconnect structure with an extreme low-k material are mainly discussed

  20. Radiation tolerance of CVD diamond detectors for pions and protons

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.

    2002-01-01

    The paper gives new results on the radiation tolerance of CVD diamond for irradiation with 300 MeV/c pions and 24 GeV/c protons. The measured charge signal spectrum is compared at several irradiation levels with the spectrum calculated by a model. Irradiation by particles causes damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model show that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal

  1. Formigas (Hymenoptera: Formicidae) Bioindicadoras de Degradação Ambiental em Poxoréu, Mato Grosso, Brasil

    OpenAIRE

    Rocha, Wilian de Oliveira; Dorval, Alberto; Peres Filho, Otávio; Vaez, Caroline dos Anjos; Ribeiro, Edilene Silva

    2015-01-01

    Este trabalho teve por objetivo avaliar as espécies de formigas que ocorrem em áreas degradadas pela mineração de diamantes, definindo as espécies bioindicadoras desta degradação. O estudo realizado entre junho de 2010 e abril de 2011, bimestralmente, em Poxoréu - MT, amostrou quatro ambientes: A1 – área degradada pela mineração; A2 – área com vegetação de cerrado antropizado recentemente; A3 – vegetação antropizada há cerca de 30 anos; A4 – área de cerrado preservado. Em cada ambiente, foram...

  2. CVD-graphene for low equivalent series resistance in rGO/CVD-graphene/Ni-based supercapacitors

    Science.gov (United States)

    Kwon, Young Hwi; Kumar, Sunil; Bae, Joonho; Seo, Yongho

    2018-05-01

    Reduced equivalent series resistance (ESR) is necessary, particularly at a high current density, for high performance supercapacitors, and the interface resistance between the current collector and electrode material is one of the main components of ESR. In this report, we have optimized chemical vapor deposition-grown graphene (CVD-G) on a current collector (Ni-foil) using reduced graphene oxide as an active electrode material to fabricate an electric double layer capacitor with reduced ESR. The CVD-G was grown at different cooling rates—20 °C min‑1, 40 °C min‑1 and 100 °C min‑1—to determine the optimum conditions. The lowest ESR, 0.38 Ω, was obtained for a cell with a 100 °C min‑1 cooling rate, while the sample without a CVD-G interlayer exhibited 0.80 Ω. The CVD-G interlayer-based supercapacitors exhibited fast CD characteristics with high scan rates up to 10 Vs‑1 due to low ESR. The specific capacitances deposited with CVD-G were in the range of 145.6 F g‑1–213.8 F g‑1 at a voltage scan rate of 0.05 V s‑1. A quasi-rectangular behavior was observed in the cyclic voltammetry curves, even at very high scan rates of 50 and 100 V s‑1, for the cell with optimized CVD-G at higher cooling rates, i.e. 100 °C min‑1.

  3. Modelling and analysis of CVD processes for ceramic membrane preparation

    NARCIS (Netherlands)

    Brinkman, H.W.; Cao, G.Z.; Meijerink, J.; de Vries, Karel Jan; Burggraaf, Anthonie

    1993-01-01

    A mathematical model is presented that describes the modified chemical vapour deposition (CVD) process (which takes place in advance of the electrochemical vapour deposition (EVD) process) to deposit ZrO2 inside porous media for the preparation and modification of ceramic membranes. The isobaric

  4. Diseño de un modelo de gestión gerencial para Univisión Optical basado en el diamante de la excelencia organizacional y el empleo del Balanced Scorecard

    OpenAIRE

    Bolaños Campoverde, Susan Catherine

    2015-01-01

    En los actuales momentos, las organizaciones tienen el reto de mejorar sus modelos de gestión para poder presentar producto y servicios que involucren calidad y excelencia competitiva. Una de las herramientas de gestión implementadas para conseguir sus propósitos de innovación y búsqueda de ventajas competitivas es orientarse bajo la corriente administración y dirección estratégica y como complemento necesario la planificación estratégica. El modelo de gestión Diamante de la Excelencia Organi...

  5. CVD polycrystalline diamond. A novel neutron detector and applications

    International Nuclear Information System (INIS)

    Mongkolnavin, R.

    1998-01-01

    Chemical Vapour Deposition (CVD) Polycrystalline Diamond film has been investigated as a low noise sensor for beta particles, gammas and neutrons using High Energy Physics technologies. Its advantages and disadvantages have been explored in comparison with other particle detectors such as silicon detector and other plastic scintillators. The performance and characteristic of the diamond detector have been fully studied and discussed. These studies will lead to a better understanding of how CVD diamonds perform as a detector and how to improve their performance under various conditions. A CVD diamond detector model has been proposed which is an attempt to explain the behaviour of such an extreme detector material. A novel neutron detector is introduced as a result of these studies. A good thermal and fast neutron detector can be fabricated with CVD diamond with new topologies. This detector will perform well without degradation in a high neutron radiation environment, as diamond is known to be radiation hard. It also offers better neutrons and gammas discrimination for high gamma background applications compared to other semiconductor detectors. A full simulation of the detector has also been done using GEANT, a Monte-Carlo simulation program for particle detectors. Simulation results show that CVD diamond detectors with this novel topology can detect neutrons with great directionality. Experimental work has been done on this detector in a nuclear reactor environment and accelerator source. A novel neutron source which offers a fast pulse high-energy neutrons has also been studied. With this detector, applications in neutron spectrometer for low-Z material have been pursued with various neutron detection techniques. One of these is a low-Z material identification system. The system has been designed and simulated for contraband luggage interrogation using the detector and the novel neutron source. Also other neutron related applications have been suggested. (author)

  6. CVD polycrystalline diamond. A novel neutron detector and applications

    International Nuclear Information System (INIS)

    Mongkolnavin, R.

    1998-07-01

    Chemical Vapour Deposition (CVD) Polycrystalline Diamond film has been investigated as a low noise sensor for beta particles, gammas and neutrons using High Energy Physics technologies. Its advantages and disadvantages have been explored in comparison with other particle detectors such as silicon detector and other plastic scintillators. The performance and characteristic of the diamond detector have been fully studied and discussed. These studies will lead to a better understanding of how CVD diamonds perform as a detector and how to improve their performance under various conditions. A CVD diamond detector model has been proposed which is an attempt to explain the behaviour of such an extreme detector material. A novel neutron detector is introduced as a result of these studies. A good thermal and fast neutron detector can be fabricated with CVD diamond with new topologies. This detector will perform well without degradation in a high neutron radiation environment, as diamond is known to be radiation-hard. It also offers better neutrons and gammas discrimination for high gamma background applications compared to other semiconductor detectors. A full simulation of the detector has also been done using GEANT, a Monte Carlo simulation program for particle detectors. Simulation results show that CVD diamond detectors with this novel topology can detect neutrons with great directionality. Experimental work has been done on this detector in a nuclear reactor environment and accelerator source. A novel neutron source which offers a fast pulse high-energy neutrons has also been studied. With this detector, applications in neutron spectrometry for low-Z material have been pursued with various neutron detection techniques. One of these is a low-Z material identification system. The system has been designed and simulated for contraband luggage interrogation using the detector and the novel neutron source. (author)

  7. Changes in CVD risk factors in the activity counseling trial

    Directory of Open Access Journals (Sweden)

    Meghan Baruth

    2011-01-01

    Full Text Available Meghan Baruth1, Sara Wilcox1, James F Sallis3, Abby C King4,5, Bess H Marcus6, Steven N Blair1,21Department of Exercise Science, 2Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Public Health Research Center, Columbia, SC, USA; 3Department of Psychology, San Diego State University, San Diego, CA, USA; 4Department of Health Research and Policy, 5Stanford Prevention Research Center, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; 6Behavioral and Social Sciences Section, Brown University Program in Public Health, Providence, RI, USAAbstract: Primary care facilities may be a natural setting for delivering interventions that focus on behaviors that improve cardiovascular disease (CVD risk factors. The purpose of this study was to examine the 24-month effects of the Activity Counseling Trial (ACT on CVD risk factors, to examine whether changes in CVD risk factors differed according to baseline risk factor status, and to examine whether changes in fitness were associated with changes in CVD risk factors. ACT was a 24-month multicenter randomized controlled trial to increase physical activity. Participants were 874 inactive men and women aged 35–74 years. Participants were randomly assigned to one of three arms that varied by level of counseling, intensity, and resource requirements. Because there were no significant differences in change over time between arms on any of the CVD risk factors examined, all arms were combined, and the effects of time, independent of arm, were examined separately for men and women. Time × Baseline risk factor status interactions examined whether changes in CVD risk factors differed according to baseline risk factor status. Significant improvements in total cholesterol, high-density lipoprotein cholesterol (HDL-C and low-density lipoprotein cholesterol, the ratio of total cholesterol to HDL-C, and triglycerides were seen in

  8. COMPARATIVE EVALUATION OF RISK FACTORS FOR CARDIOVASCULAR DISEASE (CVD) IN GENETICALLY PREDISPOSED RATS

    Science.gov (United States)

    Rodent CVD models are increasingly used for understanding individual differences in susceptibility to environmental stressors such as air pollution. We characterized pathologies and a number of known human risk factors of CVD in genetically predisposed, male young adult Spontaneo...

  9. Thermodynamic study of CVD-ZrO2 phase diagrams

    International Nuclear Information System (INIS)

    Torres-Huerta, A.M.; Vargas-Garcia, J.R.; Dominguez-Crespo, M.A.; Romero-Serrano, J.A.

    2009-01-01

    Chemical vapor deposition (CVD) of zirconium oxide (ZrO 2 ) from zirconium acetylacetonate Zr(acac) 4 has been thermodynamically investigated using the Gibbs' free energy minimization method and the FACTSAGE program. Thermodynamic data Cp o , ΔH o and S o for Zr(acac) 4 have been estimated using the Meghreblian-Crawford-Parr and Benson methods because they are not available in the literature. The effect of deposition parameters, such as temperature and pressure, on the extension of the region where pure ZrO 2 can be deposited was analyzed. The results are presented as calculated CVD stability diagrams. The phase diagrams showed two zones, one of them corresponds to pure monoclinic phase of ZrO 2 and the other one corresponds to a mix of monoclinic phase of ZrO 2 and graphite carbon.

  10. Performance of irradiated CVD diamond micro-strip sensors

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S.V.; Thomson, G.B.

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a β-source and the performance before and after intense (>10 15 /cm 2 ) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2x10 15 p/cm 2 lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9x10 15 π/cm 2 lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations

  11. Performance of irradiated CVD diamond micro-strip sensors

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D. E-mail: dirk.meier@cern.ch; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S.V.; Thomson, G.B

    2002-01-11

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a {beta}-source and the performance before and after intense (>10{sup 15}/cm{sup 2}) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2x10{sup 15} p/cm{sup 2} lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9x10{sup 15} {pi}/cm{sup 2} lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  12. Pulse height distribution and radiation tolerance of CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dangelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F. E-mail: f.hartjes@nikhef.nl; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; D.Tromson,; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Zoeller, M.; Fenyvesi, A.; Molnar, J.; Sohler, D

    2000-06-01

    The paper reviews measurements of the radiation tolerance of CVD diamond for irradiation with 24 GeV/c protons, 300 MeV/c pions and 1 MeV neutrons. For proton and neutron irradiation, the measured charge signal spectrum is compared with the spectrum calculated by a model. Irradiation by particles causes radiation damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model shows that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. In addition, we observed after proton irradiation at the charge signal spectrum a decrease of the number of small signals. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal.

  13. Performance of irradiated CVD diamond micro-strip sensors

    CERN Document Server

    Adam, W; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Krammer, Manfred; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Noomen, J; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S R; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zöller, M

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a $\\beta$-source and the performance before and after intense ($>10^{15}/{\\rm cm^2}$) proton- and pion-irradiations. We find that low dose irradiations increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiations with protons ($2.2\\times 10^{15}~p/{\\rm cm^2}$) lowers the signal-to-noise ratio slightly. Intense irradiation with pions ($2.9\\times 10^{15}~\\pi/{\\rm cm^2}$) lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  14. Performance of irradiated CVD diamond micro-strip sensors

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Pan, L. S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J. L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; Plano, R.; Somalwar, S. V.; Thomson, G. B.

    2002-01-01

    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article, we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a β-source and the performance before and after intense (>10 15/cm 2) proton- and pion-irradiations. We find that low dose irradiation increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiation with protons 2.2×10 15 p/ cm2 lowers the signal-to-noise ratio slightly. Intense irradiation with pions 2.9×10 15 π/ cm2 lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations.

  15. Assessment of CVD diamond as a thermoluminescence dosemeter material

    International Nuclear Information System (INIS)

    Borchi, E.; Furetta, C.; Leroy, C.

    1996-01-01

    Diamond has a low atomic number (Z = 6) and is therefore essentially soft tissue (Z = 7.4) equivalent. As such, diamond is an attractive material for applications in dosimetry in which the radiation absorption in the sensor material should be as close as possible to that of soft tissue. Synthetic diamond prepared by chemical vapour deposition (CVD) offers an attractive option for this application. The aim of the present work is to report results on the thermoluminescence (TL) properties of CVD diamond samples. The annealing procedures, the linearity of the TL response as a function of dose, a short-term fading experiment and some kinetic properties have been investigated and are reported here. (Author)

  16. Cold Vacuum Drying (CVD) OCRWM Loop Error Determination

    International Nuclear Information System (INIS)

    PHILIPP, B.L.

    2000-01-01

    Characterization is specifically identified by the Richland Operations Office (RL) for the Office of Civilian Radioactive Waste Management (OCRWM) of the US Department of Energy (DOE), as requiring application of the requirements in the Quality Assurance Requirements and Description (QARD) (RW-0333P DOE 1997a). Those analyses that provide information that is necessary for repository acceptance require application of the QARD. The cold vacuum drying (CVD) project identified the loops that measure, display, and record multi-canister overpack (MCO) vacuum pressure and Tempered Water (TW) temperature data as providing OCRWM data per Application of the Office of Civilian Radioactive Waste Management (OCRWM) Quality Assurance Requirements to the Hanford Spent Nuclear Fuel Project HNF-SD-SNF-RPT-007. Vacuum pressure transmitters (PT 1*08, 1*10) and TW temperature transmitters (TIT-3*05, 3*12) are used to verify drying and to determine the water content within the MCO after CVD

  17. Pulse height distribution and radiation tolerance of CVD diamond detectors

    CERN Document Server

    Adam, W; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S R; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trawick, M L; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; White, C; Zeuner, W; Zöller, M; Fenyvesi, A; Molnár, J; Sohler, D

    2000-01-01

    The paper reviews measurements of the radiation tolerance of CVD diamond for irradiation with 24 GeV/c protons, 300 MeV/c pions and 1 MeV neutrons. For proton and neutron irradiation, the measured charge signal spectrum is compared with the spectrum calculated by a model. Irradiation by particles causes radiation damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model shows that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. In addition, we observed after proton irradiation at the charge signal spectrum a decrease of the number of small signals. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal. (11 refs).

  18. Pulse height distribution and radiation tolerance of CVD diamond detectors

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dangelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; D.Tromson,; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Zoeller, M.; Fenyvesi, A.; Molnar, J.; Sohler, D.

    2000-01-01

    The paper reviews measurements of the radiation tolerance of CVD diamond for irradiation with 24 GeV/c protons, 300 MeV/c pions and 1 MeV neutrons. For proton and neutron irradiation, the measured charge signal spectrum is compared with the spectrum calculated by a model. Irradiation by particles causes radiation damage leading to a decrease of the charge signal. However, both the measurements and the outcome from the model shows that for tracker applications this drawback is at least partly counterbalanced by a narrowing of the distribution curve of the charge signal. In addition, we observed after proton irradiation at the charge signal spectrum a decrease of the number of small signals. As a result, the efficiency of a CVD diamond tracker is less affected by irradiation than the mean charge signal

  19. Crystal growth of CVD diamond and some of its peculiarities

    CERN Document Server

    Piekarczyk, W

    1999-01-01

    Experiments demonstrate that CVD diamond can form in gas environments that are carbon undersaturated with respect to diamond. This fact is, among others, the most serious violation of principles of chemical thermodynamics. In this $9 paper it is shown that none of the principles is broken when CVD diamond formation is considered not a physical process consisting in growth of crystals but a chemical process consisting in accretion of macro-molecules of polycyclic $9 saturated hydrocarbons belonging to the family of organic compounds the smallest representatives of which are adamantane, diamantane, triamantane and so forth. Since the polymantane macro-molecules are in every respect identical with $9 diamond single crystals with hydrogen-terminated surfaces, the accretion of polymantane macro- molecules is a process completely equivalent to the growth of diamond crystals. However, the accretion of macro-molecules must be $9 described in a way different from that used to describe the growth of crystals because so...

  20. Parameterisation of radiation effects on CVD diamond for proton irradiation

    International Nuclear Information System (INIS)

    Hartjes, F.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.

    1999-01-01

    The paper reviews measurements of the radiation hardness of CVD diamond for 24 GeV/c proton irradiation at fluences up to 5 * 10 15 protons/cm 2 . The results not only show radiation damage but also an annealing effect that is dominant at levels around 10 15 protons/cm 2 . A model describing both effects is introduced, enabling a prediction of the distribution curve of the charge signal for other levels

  1. Parameterisation of radiation effects on CVD diamond for proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hartjes, F.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M

    1999-08-01

    The paper reviews measurements of the radiation hardness of CVD diamond for 24 GeV/c proton irradiation at fluences up to 5{sup *}10{sup 15} protons/cm{sup 2}. The results not only show radiation damage but also an annealing effect that is dominant at levels around 10{sup 15} protons/cm{sup 2}. A model describing both effects is introduced, enabling a prediction of the distribution curve of the charge signal for other levels.

  2. CVD diamonds as thermoluminescent detectors for medical applications

    International Nuclear Information System (INIS)

    Marczewska, B.; Olko, P.; Nesladek, M.; Waligorski, M.P.R.; Kerremans, Y.

    2002-01-01

    Diamond is believed to be a promising material for medical dosimetry due to its tissue equivalence, mechanical and radiation hardness, and lack of solubility in water or in disinfecting agents. A number of diamond samples, obtained under different growth conditions at Limburg University, using the chemical vapour deposition (CVD) technique, was tested as thermoluminescence dosemeters. Their TL glow curve, TL response after doses of gamma rays, fading, and so on were studied at dose levels and for radiation modalities typical for radiotherapy. The investigated CVD diamonds displayed sensitivity comparable with that of MTS-N (Li:Mg,Ti) detectors, signal stability (reproducibility after several readouts) below 10% (1 SD) and no fading was found four days after irradiation. A dedicated CVD diamond plate was grown, cut into 20 detector chips (3x3x0.5 mm) and used for measuring the dose-depth distribution at different depths in a water phantom, for 60 Co and six MV X ray radiotherapy beams. Due to the sensitivity of diamond to ambient light, it was difficult to achieve reproducibility comparable with that of standard LiF detectors. (author)

  3. Nitrogen and hydrogen related infrared absorption in CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Titus, E. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal)]. E-mail: elby@mec.ua.pt; Ali, N. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Cabral, G. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Madaleno, J.C. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Neto, V.F. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Gracio, J. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Ramesh Babu, P [Materials Ireland, Polymer research Centre, School of Physics, Dublin (Ireland); Sikder, A.K. [Department of Physics, Indian Institute of Technology (IIT), Bombay (India); Okpalugo, T.I. [Northern Ireland Bio-Engineering Centre, NIBEC, University of Ulster (United Kingdom); Misra, D.S. [Department of Physics, Indian Institute of Technology (IIT), Bombay (India)

    2006-09-25

    In this paper, we investigate on the presence of hydrogen and nitrogen related infrared absorptions in chemical vapour deposited (CVD) diamond films. Investigations were carried out in cross sections of diamond windows, deposited using hot filament CVD (HFCVD). The results of Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and Raman spectroscopy carried out in a cross section of self-standing diamond sheets are presented. The FTIR spectra showed several features that have not been reported before. In order to confirm the frequency of nitrogen related vibrations, ab-initio calculations were carried out using GAMESS program. The investigations showed the presence of several C-N related peaks in one-phonon (1000-1333 cm{sup -1}). The deconvolution of the spectra in the three-phonon region (2700-3150 cm{sup -1}) also showed a number of vibration modes corresponding to sp {sup m}CH {sub n} phase of carbon. Elastic recoil detection analysis (ERDA) was employed to compare the H content measured using FTIR technique. Using these measurements we point out that the oscillator strength of the different IR modes varies depending upon the structure and H content of CVD diamond sheets.

  4. Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry

    International Nuclear Information System (INIS)

    Petitfils, A.

    2007-09-01

    Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

  5. Investigation of CVD graphene topography and surface electrical properties

    International Nuclear Information System (INIS)

    Wang, Rui; Pearce, Ruth; Gallop, John; Patel, Trupti; Pollard, Andrew; Hao, Ling; Zhao, Fang; Jackman, Richard; Klein, Norbert; Zurutuza, Amaia

    2016-01-01

    Combining scanning probe microscopy techniques to characterize samples of graphene, a selfsupporting, single atomic layer hexagonal lattice of carbon atoms, provides far more information than a single technique can. Here we focus on graphene grown by chemical vapour deposition (CVD), grown by passing carbon containing gas over heated copper, which catalyses single atomic layer growth of graphene on its surface. To be useful for applications the graphene must be transferred onto other substrates. Following transfer it is important to characterize the CVD graphene. We combine atomic force microscopy (AFM) and scanning Kelvin probe microscopy (SKPM) to reveal several properties of the transferred film. AFM alone provides topographic information, showing ‘wrinkles’ where the transfer provided incomplete substrate attachment. SKPM measures the surface potential indicating regions with different electronic properties for example graphene layer number. By combining AFM and SKPM local defects and impurities can also be observed. Finally, Raman spectroscopy can confirm the structural properties of the graphene films, such as the number of layers and level of disorder, by observing the peaks present. We report example data on a number of CVD samples from different sources. (paper)

  6. Mass production of CNTs using CVD multi-quartz tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yousef, Samy; Mohamed, Alaa [Dept. of Production Engineering and Printing Technology, Akhbar Elyom Academy, Giza (Egypt)

    2016-11-15

    Carbon nanotubes (CNTs) have become the backbone of modern industries, including lightweight and heavy-duty industrial applications. Chemical vapor deposition (CVD) is considered as the most common method used to synthesize high yield CNTs. This work aims to develop the traditional CVD for the mass production of more economical CNTs, meeting the growing CNT demands among consumers by increasing the number of three particular reactors. All reactors housing is connected by small channels to provide the heat exchange possibility between the chambers, thereby decreasing synthesis time and reducing heat losses inside the ceramic body of the furnace. The novel design is simple and cheap with a lower reacting time and heat loss compared with the traditional CVD design. Methane, hydrogen, argon, and catalyzed iron nanoparticles were used as a carbon source and catalyst during the synthesis process. In addition, CNTs were produced using only a single quartz tube for comparison. The produced samples were examined using XRD, TEM, SEM, FTIR, and TGA. The results showed that the yield of CNTs increases by 287 % compared with those synthesized with a single quartz tube. Moreover, the total synthesis time of CNTs decreases by 37 % because of decreased heat leakage.

  7. Nucleation of microwave plasma CVD diamond on molybdenum (Mo) substrate

    International Nuclear Information System (INIS)

    Inderjeet, K.; Ramesh, S.

    2000-01-01

    Molybdenum is a metal, which is gaining increasing significance in industrial applications. The main use of Mo is as all alloying element added in small amounts to steel, irons and non- ferrous alloys in order to enhance the strength, toughness and wear resistance. Mo is also vastly being employed in the automotive and aircraft industries, mainly due to its low coefficient of friction. Diamond, on be other hand, is a unique material for innumerable applications because of its usual combination of physical and chemical properties. Several potential applications can be anticipated for diamond in many sectors including electronics, optics, as protective corrosion resistant coatings, cutting tools, etc. With the enhancement in science and technology, diamond microcrystals and thin films are now being produced from the vapour phase by a variety of chemical vapour deposition (CVD) techniques; such as microwave plasma CVD. With such technology being made available, it is envisage that diamond-coated molybdenum would further enhance the performance and to open up new avenue for Mo in various industries. Therefore, it is the aim of the present work to study the nucleation and growth of diamond particles on Mo surface by employing microwave plasma CVD (MAPCVD). In the present work, diamond deposition was carried out in several stages by varying the deposition distance. The nucleation and growth rate were studied using scanning electron microscopy (SEM). In addition, the existence of diamond was verified by X-ray diffraction (XRD) analysis. It has been found that the nucleation and growth rate of diamond particles were influenced by the deposition height between the substrate and plasma. Under the optimum condition, well defined diamond crystallites distributed homogeneously throughout the surface, could be obtained. Some of the important parameters controlling the deposition and growth of diamond particles on Mo surface are discussed. (author)

  8. Stress analysis of CVD diamond window for ECH system

    International Nuclear Information System (INIS)

    Takahashi, Koji

    2001-03-01

    The stress analysis of a chemical vapor deposition (CVD) diamond window for Electron Cyclotron Heating and Current Drive (ECH/ECCD) system of fusion reactors is described. It was found that the real size diamond window (φ aper =70mm, t=2.25mm) withstood 14.5 atm. (1.45 MPa). The calculation results of the diamond window by ABAQUS code agree well with the results of the pressure test. The design parameters of the torus diamond window for a vacuum and a safety barrier were also obtained. (author)

  9. CVD diamond sensor for UV-photon detection

    CERN Document Server

    Periale, L; Gervino, G; Lamarina, A M; Palmisano, C; Periale, R; Picchi, P

    2012-01-01

    A new generation of UV photosensors, based on single crystal Chemical Vapour Deposition (CVD) diamonds to work optically coupled with large volume two-phase liquid-Ar (LAr) or liquid-Xe (LXe) detectors nowadays under design for the next generation of WIMPs experiments, is under development. Preliminary tests and first calibrations show these devices can have better performance than the existing UV sensitive detectors (higher photosensitivity and better signal-to-noise ratio). I-V characteristics, dark current measurements, linearity response to X-ray irradiation, and alpha-particle energy resolution are reported and discussed. (C) 2011 Elsevier B.V. All rights reserved.

  10. CVD Graphene/Ni Interface Evolution in Sulfuric Electrolyte

    DEFF Research Database (Denmark)

    Yivlialin, Rossella; Bussetti, Gianlorenzo; Duò, Lamberto

    2018-01-01

    Systems comprising single and multilayer graphene deposited on metals and immersed in acid environments have been investigated, with the aim of elucidating the mechanisms involved, for instance, in hydrogen production or metal protection from corrosion. In this work, a relevant system, namely...... chemical vapor deposited (CVD) multilayer graphene/Ni (MLGr/Ni), is studied when immersed in a diluted sulfuric electrolyte. The MLGr/Ni electrochemical and morphological properties are studied in situ and interpreted in light of the highly oriented pyrolytic graphite (HOPG) electrode behavior, when...... immersed in the same electrolyte. Following this interpretative framework, the dominant role of the Ni substrate in hydrogen production is clarified....

  11. Effects of Light Intensity Activity on CVD Risk Factors: A Systematic Review of Intervention Studies

    Directory of Open Access Journals (Sweden)

    Romeo B. Batacan

    2015-01-01

    Full Text Available The effects of light intensity physical activity (LIPA on cardiovascular disease (CVD risk factors remain to be established. This review summarizes the effects of LIPA on CVD risk factors and CVD-related markers in adults. A systematic search of four electronic databases (PubMed, Academic Search Complete, SPORTDiscus, and CINAHL examining LIPA and CVD risk factors (body composition, blood pressure, glucose, insulin, glycosylated hemoglobin, and lipid profile and CVD-related markers (maximal oxygen uptake, heart rate, C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and tumor necrosis factor receptors 1 and 2 published between 1970 and 2015 was performed on 15 March 2015. A total of 33 intervention studies examining the effect of LIPA on CVD risk factors and markers were included in this review. Results indicated that LIPA did not improve CVD risk factors and CVD-related markers in healthy individuals. LIPA was found to improve systolic and diastolic blood pressure in physically inactive populations with a medical condition. Reviewed studies show little support for the role of LIPA to reduce CVD risk factors. Many of the included studies were of low to fair study quality and used low doses of LIPA. Further studies are needed to establish the value of LIPA in reducing CVD risk.

  12. CVD-graphene growth on different polycrystalline transition metals

    Directory of Open Access Journals (Sweden)

    M. P. Lavin-Lopez

    2017-01-01

    Full Text Available The chemical vapor deposition (CVD graphene growth on two polycrystalline transition metals (Ni and Cu was investigated in detail using Raman spectroscopy and optical microscopy as a way to synthesize graphene of the highest quality (i.e. uniform growth of monolayer graphene, which is considered a key issue for electronic devices. Key CVD process parameters (reaction temperature, CH4/H2flow rate ratio, total flow of gases (CH4+H2, reaction time were optimized for both metals in order to obtain the highest graphene uniformity and quality. The conclusions previously reported in literature about the performance of low and high carbon solubility metals in the synthesis of graphene and their associated reaction mechanisms, i.e. surface depositionand precipitation on cooling, respectively, was not corroborated by the results obtained in this work. Under the optimal reaction conditions, a large percentage of monolayer graphene was obtained over the Ni foil since the carbon saturation was not complete, allowing carbon atoms to be stored in the bulk metal, which could diffuse forming high quality monolayer graphene at the surface. However, under the optimal reaction conditions, the formation of a non-uniform mixture of few layers and multilayer graphene on the Cu foil was related to the presence of an excess of active carbon atoms on the Cu surface.

  13. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    Energy Technology Data Exchange (ETDEWEB)

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  14. A study of the thermoluminescent properties of CVD diamond detectors

    International Nuclear Information System (INIS)

    Marczewska, B.; Bilski, P.; Olko, P.; Rebisz, M.; Nesladek, M.; Waligorski, M.P.R.

    2002-01-01

    A batch of 20 diamond detectors obtained by the chemical vapour deposition (CVD) method at the Institute for Materials Research at the Limburg University, Belgium, was investigated with respect to their thermoluminescent (TL) properties. The investigated detectors demonstrate TL sensitivity similar to that of the standard LiF:Mg, Ti (MTS) thermoluminescent detectors, lack of fading after two weeks from irradiation and apparent linearity of dose response. In spite of the persistent fluctuation of individual detector sensitivity observed in this batch, a new annealing procedure improved the stability of the TL signal. It has been concluded that 1 h annealing at 350 C assures the highest reproducibility for this set of detectors. A 30% discrepancy of the value of the TL signal between individual detectors from the batch may be caused by non-uniform distribution of dopants in the volume of the CVD diamond. A prototype of a planar TL reader equipped with a CCD camera was employed in this investigation. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  15. Thermoluminescence in CVD diamond films: application to actinometric dosimetry

    International Nuclear Information System (INIS)

    Barboza-Flores, M.; Melendrez, R.; Chernov, V.; Castaneda, B.; Pedroza-Montero, M.; Gan, B.; Ahn, J.; Zhang, Q.; Yoon, S.F.

    2002-01-01

    Diamond is considered a tissue-equivalent material since its atomic number (Z=6) is close to the effective atomic number of biological tissue (Z=7.42). Such a situation makes it suitable for radiation detection purposes in medical applications. In the present work the analysis is reported of the thermoluminescence (TL) and dosimetric features of chemically vapour deposited (CVD) diamond film samples subjected to ultraviolet (UV) irradiation in the actinometric region. The TL glow curve shows peaks at 120, 220, 320 and 370 deg. C. The 120 and 370 deg. C peaks are too weak and the first one fades away in a few seconds after exposure. The overall room temperature fading shows a 50% TL decay 30 min after exposure. The 320 deg. C glow peak is considered to be the most adequate for dosimetric applications due to its low fading and linear TL behaviour as a function of UV dose in the 180-260 nm range. The TL excitation spectrum presents a broad band with at least two overlapped components around 205 and 220 nm. The results indicate that the TL behaviour of CVD diamond film can be a good alternative to the currently available dosemeter and detector in the actinometric region as well as in clinical and medical applications. (author)

  16. VOx effectively doping CVD-graphene for transparent conductive films

    Science.gov (United States)

    Ji, Qinghua; Shi, Liangjing; Zhang, Qinghong; Wang, Weiqi; Zheng, Huifeng; Zhang, Yuzhi; Liu, Yangqiao; Sun, Jing

    2016-11-01

    Chemical vapor deposition(CVD)-synthesized graphene is potentially an alternative for tin-doped indium oxide (ITO) transparent conductive films (TCFs), however its sheet resistance is still too high to meet many demands. Vanadium oxide has been widely applied as smart window materials, however, no study has been reported to use it as dopant to improve the conductivity of graphene TCFs. In this study, we firstly reported that VOx doping can effectively lower the sheet resistance of CVD-graphene films while keeping its good optical properties, whose transmittance is as high as 86-90%. The optimized VOx-doped graphene exhibits a sheet resistance as low as 176 Ω/□, which decreases by 56% compared to the undoped graphene films. The doping process is convenient, stable, economical and easy to operate. What is more, VOx can effectively increase the work function(WF) of the film, making it more appropriate for use in solar cells. The evolution of the VOx species annealed at different temperatures below 400 °C has been detailed studied for the first time, based on which the doping mechanism is proposed. The prepared VOx doped graphene is expected to be a promising candidate for transparent conductive film purposes.

  17. Management of Hypertension and Other CVD Risk Factors in Egypt

    Directory of Open Access Journals (Sweden)

    Mostafa A. Abolfotouh

    2011-01-01

    Full Text Available Aim. To assess the knowledge and practice of PHC physicians toward the detection and management of hypertension (HTN and other CVD risk factors. Methods. A cross-sectional study of all primary health care physicians of the FHU of three rural districts of Egypt was conducted. Each physician was subjected to a prevalidated interview questionnaire on the WHO-CVD risk management package for low and medium resources, and a checklist of observation of daily practices. Results. Hypertension was a priority problem in about two-thirds (62.9% of physicians, yet only 19% have guidelines for HTN patients. Clinical history recording system for HNT was available for 50% of physicians. Levels of knowledge varied with regard to definition of HTN (61.3%, fair, procedures for BP measurement (43.5%, poor, indications for referral (43.5%, poor, patient counseling (61.3%, fair, patient treatment (59.8%, fair. Availability of clinical history recording system for HNT was a significant predictor for physician's level of knowledge (P=0.001. Overall level of practice was fair (68.5%. Conclusion. PHC physicians have unsatisfactory knowledge and practice on hypertension. There is a need of more continuing medical education. Local and international manuals, workshops, and seminars on how to make use of these guidelines would improve doctors' performance.

  18. Response of CVD diamond detectors to alpha radiation

    Energy Technology Data Exchange (ETDEWEB)

    Souw, E.-K. [Brookhaven National Lab., Upton, NY (United States); Meilunas, R.J. [Northrop-Grumman Corporation, Bethpage, NY 11714-3582 (United States)

    1997-11-21

    This article describes some results from an experiment with CVD diamond films used as {alpha} particle detectors. It demonstrates that bulk polarization can be effectively stopped within a reasonable time interval. This will enable detector calibration and quantitative measurement. A possible mechanism for the observed polarization quenching is discussed. It involves two types of carrier traps and a tentative band-gap model derived from the results of photoconductive current measurements. The experiment was set up mainly to investigate {alpha} detection properties of polycrystalline diamond films grown by the technique of microwave plasma enhanced chemical vapor deposition. For comparison, two commercially purchased diamond wafers were also investigated, i.e., one grown by the DC arc jet method, and the other, a type-IIa natural diamond wafer (not preselected). The best response to {alpha} particles was obtained using diamond thin-films grown by the microwave PECVD method, followed by the type-IIa natural diamond, and finally, the CVD diamond grown by the DC arc jet technique. (orig.). 43 refs.

  19. Prevalence of undiagnosed cardiovascular risk factors and 10-year CVD risk in male steel industry workers.

    Science.gov (United States)

    Gray, Benjamin J; Bracken, Richard M; Turner, Daniel; Morgan, Kerry; Mellalieu, Stephen D; Thomas, Michael; Williams, Sally P; Williams, Meurig; Rice, Sam; Stephens, Jeffrey W

    2014-05-01

    To assess the prevalence of undiagnosed cardiovascular disease (CVD) in a cohort of male steelworkers in South Wales, UK. Male steel industry workers (n = 221) with no prior diagnosis of CVD or diabetes accepted a CVD risk assessment within the work environment. Demographic, anthropometric, family, and medical histories were all recorded and capillary blood samples obtained. The 10-year CVD risk was predicted using the QRISK2-2012 algorithm. Up to 81.5% of workers were either overweight or obese. More than 20% of workers were found to have diastolic hypertension, high total cholesterol, and/or a total cholesterol/high-density lipoprotein ratio of six or more. Over one quarter of workers assessed had an increased 10-year CVD risk. Despite a physically demanding occupation, risk assessment in the workplace uncovered significant occult factors in CVD risk in a sample of male heavy industry workers.

  20. Thermal Analysis of Cold Vacuum Drying (CVD) of Spent Nuclear Fuel (SNF)

    International Nuclear Information System (INIS)

    PIEPHO, M.G.

    2000-01-01

    The thermal analysis examined transient thermal and chemical behavior of the Multi-Canister Overpack (MCO) container for a broad range of cases that represent the Cold Vacuum Drying (CVD) processes. The cases were defined to consider both normal and off-normal operations at the CVD Facility for an MCO with N Reactor spent fuel. This analysis provides the basis for the MCO thermal behavior at the CVD Facility in support of the safety basis documentation

  1. Upper pliocene-lower pleistocene 40Ar/39Ar ages of Pudahuel ignimbrite (Diamante-Maipo volcanic complex), Central Chile (33.50S)

    International Nuclear Information System (INIS)

    Wall, R.M.; Lara, L.E.; Perez de Arce, C

    2001-01-01

    brittle deformation, the age of N-S compressive event recognized by Lavenu and Cembrano (1999) toward the south in the Central Depression is constrained. Thus, the Pudahuel Ignimbrite (Diamante-Maipo Volcanic Complex) is part of a Plio-Quaternary silicic magmatic belt formed by the NNW alignment of volcanic centres and complexes like the Calabozos Caldera (35.5 o S ), with pleistocene pyroclastic flow deposits (Hildreth et al., 1984; Grunder and Mahood, 1988); the Puelche Volcanic Field (35.7 o S ), with rhyolitic lavas of Early Pleistocene age (Hildreth et al., 1999); the Laguna del Maule Volcanic Field (36 o S ) with plio-pleistocene lavas and ignimbrites (Hildreth et al., 1999) and Domuyo volcano (36.7 o S ) in Argentina. This belt is superimposed on rocks which are deformed by the Tertiary Malargue fold and thrust belt. To the south of 38 o S , and with the same orientation, another coeval magmatic belt is formed by alkaline basaltic centres (Munoz y Stern, 1989) (au)

  2. A measure of the interfacial shear strength between SiC(CVD)/B(CVD) filament--aluminum matrix by fragmentation method

    International Nuclear Information System (INIS)

    Jiang, Y.Q.; Chen, X.J.; Yang, D.M.; Fei, X.; Pan, J.

    1993-01-01

    The tensile specimens used are of dog-bone shape and consist of single axial SiC (CVD) /B (CVD) filament processed by CVD and embedded in a LD-2 aluminum alloy. Model composite specimens have been fabricated by a high pressure squeeze casting technique. This paper describes the application of an Acoustic Emission Technique for locating the position of fiber breaks and thus determining the length distribution of fiber fragments resulting when a composite specimen containing a single fiber is loaded to failure. The critical lengths (minimal lengths) are checked by Corrosion Method

  3. Studies of mono-crystalline CVD diamond pixel detectors

    CERN Document Server

    Bartz, E; Atramentov, O; Yang, Z; Hall-Wilton, R; Schnetzer, S; Patel, R; Bugg, W; Hebda, P; Halyo, V; Hunt, A; Marlow, D; Steininger, H; Ryjov, V; Hits, D; Spanier, S; Pernicka, M; Johns, W; Doroshenko, J; Hollingsworth, M; Harrop, B; Farrow, C; Stone, R

    2011-01-01

    The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in several three layered pixel diamond detectors that are aligned precisely with respect to each other and the beam direction. At a lower rate it also performs particle track position measurements. The PLTs mono-crystalline CVD diamonds are bump-bonded to the same readout chip used in the silicon pixel system in CMS. Mono-crystalline diamond detectors have many attributes that make them desirable for use in charged particle tracking in radiation hostile environments such as the LHC. In order to further characterize the applicability of diamond technology to charged particle tracking we performed several tests with particle beams that included a measurement of the intrinsic spatial resolution with a high resolution beam telescope. Published by Elsevier B.V.

  4. Oxidation kinetics of CVD silicon carbide and silicon nitride

    Science.gov (United States)

    Fox, Dennis S.

    1992-01-01

    The long-term oxidation behavior of pure, monolithic CVD SiC and Si3N4 is studied, and the isothermal oxidation kinetics of these two materials are obtained for the case of 100 hrs at 1200-1500 C in flowing oxygen. Estimates are made of lifetimes at the various temperatures investigated. Parabolic rate constants for SiC are within an order of magnitude of shorter exposure time values reported in the literature. The resulting silica scales are in the form of cristobalite, with cracks visible after exposure. The oxidation protection afforded by silica for these materials is adequate for long service times under isothermal conditions in 1-atm dry oxygen.

  5. Studies of mono-crystalline CVD diamond pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bugg, W. [University of Tennessee, Knoxville (United States); Hollingsworth, M., E-mail: mhollin3@utk.edu [University of Tennessee, Knoxville (United States); Spanier, S.; Yang, Z. [University of Tennessee, Knoxville (United States); Bartz, E.; Doroshenko, J.; Hits, D.; Schnetzer, S.; Stone, R.; Atramentov, O.; Patel, R.; Barker, A. [Rutgers University, Piscataway (United States); Hall-Wilton, R.; Ryjov, V.; Farrow, C. [CERN, Geneva (Switzerland); Pernicka, M.; Steininger, H. [HEPHY, Vienna (Austria); Johns, W. [Vanderbilt University, Nashville (United States); Halyo, V.; Harrop, B. [Princeton University, Princeton (United States); and others

    2011-09-11

    The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in several three layered pixel diamond detectors that are aligned precisely with respect to each other and the beam direction. At a lower rate it also performs particle track position measurements. The PLT's mono-crystalline CVD diamonds are bump-bonded to the same readout chip used in the silicon pixel system in CMS. Mono-crystalline diamond detectors have many attributes that make them desirable for use in charged particle tracking in radiation hostile environments such as the LHC. In order to further characterize the applicability of diamond technology to charged particle tracking we performed several tests with particle beams that included a measurement of the intrinsic spatial resolution with a high resolution beam telescope.

  6. Dimensionless Numbers Expressed in Terms of Common CVD Process Parameters

    Science.gov (United States)

    Kuczmarski, Maria A.

    1999-01-01

    A variety of dimensionless numbers related to momentum and heat transfer are useful in Chemical Vapor Deposition (CVD) analysis. These numbers are not traditionally calculated by directly using reactor operating parameters, such as temperature and pressure. In this paper, these numbers have been expressed in a form that explicitly shows their dependence upon the carrier gas, reactor geometry, and reactor operation conditions. These expressions were derived for both monatomic and diatomic gases using estimation techniques for viscosity, thermal conductivity, and heat capacity. Values calculated from these expressions compared well to previously published values. These expressions provide a relatively quick method for predicting changes in the flow patterns resulting from changes in the reactor operating conditions.

  7. Tests of Hercules/Ultramet CVD coatings in hot hydrogen

    International Nuclear Information System (INIS)

    Vanier, P.E.; Barletta, R.E.; Svandrlik, J.; Adams, J.

    1992-01-01

    The effort by Hercules and Ultramet to produce CVD NbC coatings, which protect carbon-carbon substrates from hot hydrogen, has had some success but with some limitations. The coatings increase the survival time at atmospheric pressure and low flow rate of hydrogen by about a factor of 40 over uncoated graphite at 3000 K. However, the grain structure is not stable at these temperatures, and after about 10--20 minutes, the coating is subject to rapid degradation by spalling in visible chunks. Further experiments would have to be performed to determine the effects of higher pressures and flow rates, for it is not clear how these factors would affect the survival time, considering that one of the main failure mechanisms is independent of the atmosphere

  8. Polycrystalline CVD diamond device level modeling for particle detection applications

    Science.gov (United States)

    Morozzi, A.; Passeri, D.; Kanxheri, K.; Servoli, L.; Lagomarsino, S.; Sciortino, S.

    2016-12-01

    Diamond is a promising material whose excellent physical properties foster its use for radiation detection applications, in particular in those hostile operating environments where the silicon-based detectors behavior is limited due to the high radiation fluence. Within this framework, the application of Technology Computer Aided Design (TCAD) simulation tools is highly envisaged for the study, the optimization and the predictive analysis of sensing devices. Since the novelty of using diamond in electronics, this material is not included in the library of commercial, state-of-the-art TCAD software tools. In this work, we propose the development, the application and the validation of numerical models to simulate the electrical behavior of polycrystalline (pc)CVD diamond conceived for diamond sensors for particle detection. The model focuses on the characterization of a physically-based pcCVD diamond bandgap taking into account deep-level defects acting as recombination centers and/or trap states. While a definite picture of the polycrystalline diamond band-gap is still debated, the effect of the main parameters (e.g. trap densities, capture cross-sections, etc.) can be deeply investigated thanks to the simulated approach. The charge collection efficiency due to β -particle irradiation of diamond materials provided by different vendors and with different electrode configurations has been selected as figure of merit for the model validation. The good agreement between measurements and simulation findings, keeping the traps density as the only one fitting parameter, assesses the suitability of the TCAD modeling approach as a predictive tool for the design and the optimization of diamond-based radiation detectors.

  9. CVD diamond Brewster window: feasibility study by FEM analyses

    Directory of Open Access Journals (Sweden)

    Vaccaro A.

    2012-09-01

    Full Text Available Chemical vapor deposition (CVD diamond windows are a crucial component in heating and current drive (H&CD applications. In order to minimize the amount of reflected power from the diamond disc, its thickness must match the desired beam wavelength, thus proper targeting of the plasma requires movable beam reflectors. This is the case, for instance, of the ITER electron cyclotron H&CD system. However, looking at DEMO, the higher heat loads and neutron fluxes could make the use of movable parts close to the plasma difficult. The issue might be solved by using gyrotrons able to tune the beam frequency to the desired resonance, but this concept requires transmission windows that work in a given frequency range, such as the Brewster window. It consists of a CVD diamond disc brazed to two copper cuffs at the Brewster angle. The brazing process is carried out at about 800°C and then the temperature is decreased down to room temperature. Diamond and copper have very different thermal expansion coefficients, therefore high stresses build up during the cool down phase that might lead to failure of the disc. Considering also the complex geometry of the window with the skewed position of the disc, analyses are required in the first place to check its feasibility. The cool down phase was simulated by FEM structural analyses for several geometric and constraint configurations of the window. A study of indirect cooling of the window by water was also performed considering a HE11 mode beam. The results are here reported.

  10. Chemical Vapor-Deposited (CVD) Diamond Films for Electronic Applications

    Science.gov (United States)

    1995-01-01

    Diamond films have a variety of useful applications as electron emitters in devices such as magnetrons, electron multipliers, displays, and sensors. Secondary electron emission is the effect in which electrons are emitted from the near surface of a material because of energetic incident electrons. The total secondary yield coefficient, which is the ratio of the number of secondary electrons to the number of incident electrons, generally ranges from 2 to 4 for most materials used in such applications. It was discovered recently at the NASA Lewis Research Center that chemical vapor-deposited (CVD) diamond films have very high secondary electron yields, particularly when they are coated with thin layers of CsI. For CsI-coated diamond films, the total secondary yield coefficient can exceed 60. In addition, diamond films exhibit field emission at fields orders of magnitude lower than for existing state-of-the-art emitters. Present state-of-the-art microfabricated field emitters generally require applied fields above 5x10^7 V/cm. Research on field emission from CVD diamond and high-pressure, high-temperature diamond has shown that field emission can be obtained at fields as low as 2x10^4 V/cm. It has also been shown that thin layers of metals, such as gold, and of alkali halides, such as CsI, can significantly increase field emission and stability. Emitters with nanometer-scale lithography will be able to obtain high-current densities with voltages on the order of only 10 to 15 V.

  11. Polycrystalline CVD diamond device level modeling for particle detection applications

    International Nuclear Information System (INIS)

    Morozzi, A.; Passeri, D.; Kanxheri, K.; Servoli, L.; Lagomarsino, S.; Sciortino, S.

    2016-01-01

    Diamond is a promising material whose excellent physical properties foster its use for radiation detection applications, in particular in those hostile operating environments where the silicon-based detectors behavior is limited due to the high radiation fluence. Within this framework, the application of Technology Computer Aided Design (TCAD) simulation tools is highly envisaged for the study, the optimization and the predictive analysis of sensing devices. Since the novelty of using diamond in electronics, this material is not included in the library of commercial, state-of-the-art TCAD software tools. In this work, we propose the development, the application and the validation of numerical models to simulate the electrical behavior of polycrystalline (pc)CVD diamond conceived for diamond sensors for particle detection. The model focuses on the characterization of a physically-based pcCVD diamond bandgap taking into account deep-level defects acting as recombination centers and/or trap states. While a definite picture of the polycrystalline diamond band-gap is still debated, the effect of the main parameters (e.g. trap densities, capture cross-sections, etc.) can be deeply investigated thanks to the simulated approach. The charge collection efficiency due to β -particle irradiation of diamond materials provided by different vendors and with different electrode configurations has been selected as figure of merit for the model validation. The good agreement between measurements and simulation findings, keeping the traps density as the only one fitting parameter, assesses the suitability of the TCAD modeling approach as a predictive tool for the design and the optimization of diamond-based radiation detectors.

  12. Organic solar cells using CVD-grown graphene electrodes

    International Nuclear Information System (INIS)

    Kim, Hobeom; Han, Tae-Hee; Lim, Kyung-Geun; Lee, Tae-Woo; Bae, Sang-Hoon; Ahn, Jong-Hyun

    2014-01-01

    We report on the development of flexible organic solar cells (OSCs) incorporating graphene sheets synthesized by chemical vapor deposition (CVD) as transparent conducting electrodes on polyethylene terephthalate (PET) substrates. A key barrier that must be overcome for the successful fabrication of OSCs with graphene electrodes is the poor-film properties of water-based poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) when coated onto hydrophobic graphene surfaces. To form a uniform PEDOT:PSS film on a graphene surface, we added perfluorinated ionomers (PFI) to pristine PEDOT:PSS to create ‘GraHEL’, which we then successfully spin coated onto the graphene surface. We systematically investigated the effect of number of layers in layer-by-layer stacked graphene anode of an OSC on the performance parameters including the open-circuit voltage (V oc ), short-circuit current (J sc ), and fill factor (FF). As the number of graphene layers increased, the FF tended to increase owing to lower sheet resistance, while J sc tended to decrease owing to the lower light absorption. In light of this trade-off between sheet resistance and transmittance, we determined that three-layer graphene (3LG) represents the best configuration for obtaining the optimal power conversion efficiency (PCE) in OSC anodes, even at suboptimal sheet resistances. We finally developed efficient, flexible OSCs with a PCE of 4.33%, which is the highest efficiency attained so far by an OSC with CVD-grown graphene electrodes to the best of our knowledge. (paper)

  13. Universal Design: Supporting Students with Color Vision Deficiency (CVD) in Medical Education

    Science.gov (United States)

    Meeks, Lisa M.; Jain, Neera R.; Herzer, Kurt R.

    2016-01-01

    Color Vision Deficiency (CVD) is a commonly occurring condition in the general population. For medical students, it has the potential to create unique challenges in the classroom and clinical environments. Few studies have provided medical educators with comprehensive recommendations to assist students with CVD. This article presents a focused…

  14. Origin, state of the art and some prospects of the diamond CVD

    CERN Document Server

    Spitsyn, B V; Alexenko, A E

    2000-01-01

    A short review on the diamond CVD origin, together with its state of the art and some prospects was given. New hybrid methods of the diamond CVD permit to gain 1.2 to 6 times of growth rate in comparison with ordinary diamond CVD's. Recent results on n-type diamond film synthesis through phosphorus doping in the course of the CVD process are briefly discussed. In comparison with high-pressure diamond synthesis, the CVD processes open new facets of the diamond as ultimate crystal for science and technology evolution. It was stressed that, mainly on the basis of new CVDs of diamond, the properties of natural diamond are not only reproduced, but can be surpassed. As examples, mechanical (fracture resistance), physical (thermal conductivity), and chemical (oxidation stability) properties are mentioned. Some present issues in the field are considered.

  15. 25th anniversary article: CVD polymers: a new paradigm for surface modification and device fabrication.

    Science.gov (United States)

    Coclite, Anna Maria; Howden, Rachel M; Borrelli, David C; Petruczok, Christy D; Yang, Rong; Yagüe, Jose Luis; Ugur, Asli; Chen, Nan; Lee, Sunghwan; Jo, Won Jun; Liu, Andong; Wang, Xiaoxue; Gleason, Karen K

    2013-10-11

    Well-adhered, conformal, thin (polymers can be achieved on virtually any substrate: organic, inorganic, rigid, flexible, planar, three-dimensional, dense, or porous. In CVD polymerization, the monomer(s) are delivered to the surface through the vapor phase and then undergo simultaneous polymerization and thin film formation. By eliminating the need to dissolve macromolecules, CVD enables insoluble polymers to be coated and prevents solvent damage to the substrate. CVD film growth proceeds from the substrate up, allowing for interfacial engineering, real-time monitoring, and thickness control. Initiated-CVD shows successful results in terms of rationally designed micro- and nanoengineered materials to control molecular interactions at material surfaces. The success of oxidative-CVD is mainly demonstrated for the deposition of organic conducting and semiconducting polymers. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. NEXAFS Study of the Annealing Effect on the Local Structure of FIB-CVD DLC

    International Nuclear Information System (INIS)

    Saikubo, Akihiko; Kato, Yuri; Igaki, Jun-ya; Kanda, Kazuhiro; Matsui, Shinji; Kometani, Reo

    2007-01-01

    Annealing effect on the local structure of diamond like carbon (DLC) formed by focused ion beam-chemical vapor deposition (FIB-CVD) was investigated by the measurement of near edge x-ray absorption fine structure (NEXAFS) and energy dispersive x-ray (EDX) spectra. Carbon K edge absorption NEXAFS spectrum of FIB-CVD DLC was measured in the energy range of 275-320 eV. In order to obtain the information on the location of the gallium in the depth direction, incidence angle dependence of NEXAFS spectrum was measured in the incident angle range from 0 deg. to 60 deg. . The peak intensity corresponding to the resonance transition of 1s→σ* originating from carbon-gallium increased from the FIB-CVD DLC annealed at 200 deg. C to the FIB-CVD DLC annealed at 400 deg. C and decreased from that at 400 deg. C to that at 600 deg. C. Especially, the intensity of this peak remarkably enhanced in the NEXAFS spectrum of the FIB-CVD DLC annealed at 400 deg. C at the incident angle of 60 deg. . On the contrary, the peak intensity corresponding to the resonance transition of 1s→π* originating from carbon double bonding of emission spectrum decreased from the FIB-CVD DLC annealed at 200 deg. C to that at 400 deg. C and increased from that at 400 deg. C to that at 600 deg. C. Gallium concentration in the FIB-CVD DLC decreased from ≅2.2% of the as-deposited FIB-CVD DLC to ≅1.5% of the FIB-CVD DLC annealed at 600 deg. C from the elementary analysis using EDX. Both experimental results indicated that gallium atom departed from FIB-CVD DLC by annealing at the temperature of 600 deg. C

  17. Determinação voltamétrica de amitriptilina em formulações farmacêuticas com eletrodo de diamante dopado com boro explorando medidas em meio ácido

    Directory of Open Access Journals (Sweden)

    Eduardo Henrique Duarte

    2014-01-01

    Full Text Available A simple and reliable voltammetric method is presented for the determination of amitriptyline using a boron-doped diamond electrode in 0.1 mol L-1 sulfuric acid solution as the support electrolyte. Under optimized differential pulse voltammetry conditions (modulation time 5 ms, scan rate 70 mV s-1, and pulse amplitude 120 mV, the electrode provides linear responses to amitriptyline in the concentration range 1.05 to 92.60 µmol L-1 and at a detection limit of 0.52 µmol L-1. The proposed method was successfully applied in pharmaceutical formulations, with results similar to those obtained using UV-vis spectrophotometric method as reference (at 95% confidence level, as recommended by the Brazilian Pharmacopoeia.

  18. Facility for continuous CVD coating of ceramic fibers

    International Nuclear Information System (INIS)

    Moore, A.W.

    1992-01-01

    The development of new and improved ceramic fibers has spurred the development and application of ceramic composites with improved strength, strength/weight ratio, toughness, and durability at increasingly high temperatures. For many systems, the ceramic fibers can be used without modification because their properties are adequate for the chosen application. However, in order to take maximum advantage of the fiber properties, it is often necessary to coat the ceramic fibers with materials of different composition and properties. Examples include (1) boron nitride coatings on a ceramic fiber, such as Nicalon silicon carbide, to prevent reaction with the ceramic matrix during fabrication and to enhance fiber pullout and increase toughness when the ceramic composite is subjected to stress; (2) boron nitride coatings on ceramic yarns, such as Nicalon for use as thermal insulation panels in an aerodynamic environment, to reduce abrasion of the Nicalon and to inhibit the oxidation of free carbon contained within the Nicalon; and (3) ceramic coatings on carbon yarns and carbon-carbon composites to permit use of these high-strength, high-temperature materials in oxidizing environments at very high temperatures. This paper describes a pilot-plant-sized CVD facility for continuous coating of ceramic fibers and some of the results obtained so far with this equipment

  19. Selective tungsten deposition in a batch cold wall CVD system

    International Nuclear Information System (INIS)

    Chow, R.; Kang, S.; Harshbarger, W.R.; Susoeff, M.

    1987-01-01

    Selective deposition of tungsten offers many advantages for VLSI technology. The process can be used as a planarization technique for multilevel interconnect technology, it can be used to fill contacts and to provide a barrier layer between Al and Si materials, and the selective W process might be used as a self-aligned technology to provide low resistance layers on source/drain and gate conductors. Recent publications have indicate that cold wall CVD systems provide advantages for development of selective W process. Genus has investigated selective W deposition processing, and we have developed a selective W deposition process for the Genus 8402 multifilm deposition system. This paper describes the Genus 8402 system and the selective W process developed in this reactor. To further develop selective W technology, Genus has signed an agreement with General Electric establishing a joint development program. As a part of this program, the authors characterized the selective W process for encroachment, Si consumption and degrees of selectivity on various dielectrics. The status of this development activity and process characterization is reviewed in this paper

  20. Carbon Nanotubes Growth by CVD on Graphite Fibers

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Cochrane, J. C.; Lehoczky, S. L.; Muntele, I.; Ila, D.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Due to the superior electrical and mechanical properties of carbon nanotubes (CNT), synthesizing CNT on various substances for electronics devices and reinforced composites have been engaged in many efforts for applications. This presentation will illustrate CNT synthesized on graphite fibers by thermal CVD. On the fiber surface, iron nanoparticles as catalysts for CNT growth are coated. The growth temperature ranges from 600 to 1000 C and the pressure ranges from 100 Torr to one atmosphere. Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis. At high growth temperatures (greater than or equal to 900 C), the rapid inter-diffusion of the transition metal iron on the graphite surface results in the rough fiber surface without any CNT grown on it. When the growth temperature is relative low (650-800 C), CNT with catalytic particles on the nanotube top ends are fabricated on the graphite surface. (Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis.) (By measuring the samples) Using micro Raman spectroscopy in the breath mode region, single-walled or multi-walled CNT (MWCNT), depending on growth concentrations, are found. Morphology, length and diameter of these MWCNT are determined by scanning electron microscopy and Raman spectroscopy. The detailed results of syntheses and characterizations will be discussed in the presentation.

  1. Cyclic voltammetry response of an undoped CVD diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Fabisiak, K., E-mail: kfab@ukw.edu.pl [Institute of Physics, Kazimierz Wielki University, Powstancow Wielkopolskich 2, 85-090 Bydgoszcz (Poland); Torz-Piotrowska, R. [Faculty of Chemical Technology and Engineering, UTLS Seminaryjna 3, 85-326 Bydgoszcz (Poland); Staryga, E. [Institute of Physics, Technical University of Lodz, Wolczanska 219, 90-924 Lodz (Poland); Szybowicz, M. [Faculty of Technical Physics, Poznan University of Technology, Nieszawska 13A, 60-965 Poznan (Poland); Paprocki, K.; Popielarski, P.; Bylicki, F. [Institute of Physics, Kazimierz Wielki University, Powstancow Wielkopolskich 2, 85-090 Bydgoszcz (Poland); Wrzyszczynski, A. [Institute of Physics, Technical University of Lodz, Wolczanska 219, 90-924 Lodz (Poland)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Correlation was found between diamond quality and its electrochemical performance. Black-Right-Pointing-Pointer The electrode sensitivity depends on the content of sp{sup 2} carbon phase in diamond layer. Black-Right-Pointing-Pointer The sp{sup 2} carbon phase content has little influence on the CV peak separation ({Delta}E{sub p}). - Abstract: The polycrystalline undoped diamond layers were deposited on tungsten wire substrates by using hot filament chemical vapor deposition (HFCVD) technique. As a working gas the mixture of methanol in excess of hydrogen was used. The morphologies and quality of as-deposited films were monitored by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy respectively. The electrochemical activity of the obtained diamond layers was monitored by using cyclic voltammetry measurements. Analysis of the ferrocyanide-ferricyanide couple at undoped diamond electrode suggests that electrochemical reaction at diamond electrode has a quasireversibile character. The ratio of the anodic and cathodic peak currents was always close to unity. In this work we showed that the amorphous carbon admixture in the CVD diamond layer has a crucial influence on its electrochemical performance.

  2. A Fast CVD Diamond Beam Loss Monitor for LHC

    CERN Document Server

    Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

    2011-01-01

    Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

  3. Investigation of laser ablation of CVD diamond film

    Science.gov (United States)

    Chao, Choung-Lii; Chou, W. C.; Ma, Kung-Jen; Chen, Ta-Tung; Liu, Y. M.; Kuo, Y. S.; Chen, Ying-Tung

    2005-04-01

    Diamond, having many advanced physical and mechanical properties, is one of the most important materials used in the mechanical, telecommunication and optoelectronic industry. However, high hardness value and extreme brittleness have made diamond extremely difficult to be machined by conventional mechanical grinding and polishing. In the present study, the microwave CVD method was employed to produce epitaxial diamond films on silicon single crystal. Laser ablation experiments were then conducted on the obtained diamond films. The underlying material removal mechanisms, microstructure of the machined surface and related machining conditions were also investigated. It was found that during the laser ablation, peaks of the diamond grains were removed mainly by the photo-thermal effects introduced by excimer laser. The diamond structures of the protruded diamond grains were transformed by the laser photonic energy into graphite, amorphous diamond and amorphous carbon which were removed by the subsequent laser shots. As the protruding peaks gradually removed from the surface the removal rate decreased. Surface roughness (Ra) was improved from above 1μm to around 0.1μm in few minutes time in this study. However, a scanning technique would be required if a large area was to be polished by laser and, as a consequence, it could be very time consuming.

  4. Experimental studies of N~+ implantation into CVD diamond thin films

    Institute of Scientific and Technical Information of China (English)

    辛火平; 林成鲁; 王建新; 邹世昌; 石晓红; 林梓鑫; 周祖尧; 刘祖刚

    1997-01-01

    The effects of N+ implantation under various conditions on CVD diamond films were analyzed with Raman spectroscopy, four-point probe method, X-ray diffraction (XRD), Rutherford backseattering spectroscopy (RBS), ultraviolet photoluminescence spectroscopy (UV-PL), Fourier transformation infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the N+ implantation doping without any graphitization has been successfully realized when 100 keV N+ ions at a dosage of 2 × 1016 cm-2 were implanted into diamond films at 550℃ . UV-PL spectra indicate that the implanted N+ ions formed an electrically inactive deep-level impurity in diamond films. So the sheet resistance of the sample after N+ implantation changed little. Carbon nitride containing C≡N covalent bond has been successfully synthesized by 100 keV, 1.2×1018 N/cm2 N+ implantation into diamond films. Most of the implanted N+ ions formed C≡N covalent bonds with C atoms. The others were free state nitroge

  5. CVD and obesity in transitional Syria: a perspective from the Middle East.

    Science.gov (United States)

    Barakat, Hani; Barakat, Hanniya; Baaj, Mohamad K

    2012-01-01

    Syria is caught in the middle of a disruptive nutritional transition. Its healthcare system is distracted by challenges and successes in other areas while neglecting to address the onslaught of Syria's cardiovascular disease (CVD) epidemic. Despite the official viewpoint touting improvement in health indicators, current trends jeopardize population health, and several surveys in the Syrian population signal the epidemic spreading far and wide. The goal is to counteract the indifference towards obesity as a threat to Syrian's health, as the country is slowly becoming a leader in CVD mortality globally. PubMed, World Health Organization, and official government websites were searched for primary surveys in Syria related to CVD morbidity, mortality, and risk factors. Inclusion criteria ensured that results maximized relevance while producing comparable studies. Statistical analysis was applied to detect the most common risk factor and significant differences in risk factor prevalence and CVD rates. Obesity remained the prevailing CVD risk factor except in older Syrian men, where smoking and hypertension were more common. CVD mortality was more common in males due to coronary disease, while stroke dominated female mortality. The young workforce is especially impacted, with 50% of CVD mortality occurring before age 65 years and an 81% prevalence of obesity in women over 45 years. Syria can overcome its slow response to the CVD epidemic and curb further deterioration by reducing obesity and, thus, inheritance and clustering of risk factors. This can be achieved via multilayered awareness and intensive parental and familial involvement. Extinguishing the CVD epidemic is readily achievable as demonstrated in other countries.

  6. Development of a CVD silica coating for UK advanced gas-cooled nuclear reactor fuel pins

    International Nuclear Information System (INIS)

    Bennett, M.J.; Houlton, M.R.; Moore, D.A.; Foster, A.I.; Swidzinski, M.A.M.

    1983-04-01

    Vapour deposited silica coatings could extend the life of the 20% Cr/25% Ni niobium stabilised (20/25/Nb) stainless steel fuel cladding of the UK advanced gas cooled reactors. A CVD coating process developed originally to be undertaken at atmospheric pressure has now been adapted for operation at reduced pressure. Trials on the LP CVD process have been pursued to the production scale using commercial equipment. The effectiveness of the LP CVD silica coatings in providing protection to 20/25/Nb steel surfaces against oxidation and carbonaceous deposition has been evaluated. (author)

  7. Radiation monitoring with CVD diamonds and PIN diodes at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Bruinsma, M. [University of California Irvine, Irvine, CA 92697 (United States); Burchat, P. [Stanford University, Stanford, CA 94305-4060 (United States); Curry, S. [University of California Irvine, Irvine, CA 92697 (United States)], E-mail: scurry@slac.stanford.edu; Edwards, A.J. [Stanford University, Stanford, CA 94305-4060 (United States); Kagan, H.; Kass, R. [Ohio State University, Columbus, OH 43210 (United States); Kirkby, D. [University of California Irvine, Irvine, CA 92697 (United States); Majewski, S.; Petersen, B.A. [Stanford University, Stanford, CA 94305-4060 (United States)

    2007-12-11

    The BaBar experiment at the Stanford Linear Accelerator Center has been using two polycrystalline chemical vapor deposition (pCVD) diamonds and 12 silicon PIN diodes for radiation monitoring and protection of the Silicon Vertex Tracker (SVT). We have used the pCVD diamonds for more than 3 years, and the PIN diodes for 7 years. We will describe the SVT and SVT radiation monitoring system as well as the operational difficulties and radiation damage effects on the PIN diodes and pCVD diamonds in a high-energy physics environment.

  8. Multilayered and composite PVD-CVD coatings in cemented carbides manufacture

    International Nuclear Information System (INIS)

    Glushkov, V.N.; Anikeev, A.I.; Anikin, V.N.; Vereshchaka, A.S.

    2001-01-01

    Carbide cutting tools with wear-resistant coatings deposited by CVD process are widely employed in mechanical engineering to ensure a substantially longer service life of tool systems. However, the relatively high temperature and long time of the process make the substrate decarburise and, as a result, the bend strength and performance characteristics of a tool decrease. The present study suggests the problem of deteriorated strength of CVD-coated carbide tools be solved by the development of a technology that combines arc-PVD and CVD processes to deposit multilayered coatings of titanium and aluminium compounds. (author)

  9. Treatment with liraglutide may improve markers of CVD reflected by reduced levels of apoB

    DEFF Research Database (Denmark)

    Engelbrechtsen, Line; Lundgren, J; Wewer Albrechtsen, Nicolai Jacob

    2017-01-01

    Background: Dislipidaemia and increased levels of apolipoprotein B (apoB) in individuals with obesity are risk factors for development of cardiovascular disease (CVD). The aim of this study was to investigate the effect of weight loss and weight maintenance with and without liraglutide treatment ......B, despite similar body weight maintenance. Treatment with liraglutide may therefore reduce apoB levels and thus reflect lower CVD risk. Including apoB measurements in clinical practice when monitoring patients with dislipidemia or CVD might prove to be useful....

  10. CVD transfer-free graphene for sensing applications

    Directory of Open Access Journals (Sweden)

    Chiara Schiattarella

    2017-05-01

    Full Text Available The sp2 carbon-based allotropes have been extensively exploited for the realization of gas sensors in the recent years because of their high conductivity and large specific surface area. A study on graphene that was synthetized by means of a novel transfer-free fabrication approach and is employed as sensing material is herein presented. Multilayer graphene was deposited by chemical vapour deposition (CVD mediated by CMOS-compatible Mo. The utilized technique takes advantage of the absence of damage or contamination of the synthesized graphene, because there is no need for the transfer onto a substrate. Moreover, a proper pre-patterning of the Mo catalyst allows one to obtain graphene films with different shapes and dimensions. The sensing properties of the material have been investigated by exposing the devices to NO2, NH3 and CO, which have been selected because they are well-known hazardous substances. The concentration ranges have been chosen according to the conventional monitoring of these gases. The measurements have been carried out in humid N2 environment, setting the flow rate at 500 sccm, the temperature at 25 °C and the relative humidity (RH at 50%. An increase of the conductance response has been recorded upon exposure towards NO2, whereas a decrease of the signal has been detected towards NH3. The material appears totally insensitive towards CO. Finally, the sensing selectivity has been proven by evaluating and comparing the degree of adsorption and the interaction energies for NO2 and NH3 on graphene. The direct-growth approach for the synthesis of graphene opens a promising path towards diverse applicative scenarios, including the straightforward integration in electronic devices.

  11. A study of diaschisis in CVD using MR-CT

    International Nuclear Information System (INIS)

    Okada, Akihiko; Fujimoto, Toshiro; Uetsuhara, Koichi; Asakura, Tetsuhiko; Osame, Mitsuhiro; Igata, Akihiro.

    1987-01-01

    The presence of diaschisis in the non-infarct cerebral areas in a cerebro-vascular disorder (CVD) has been reported using PET and cerebral-blood flowmetry. We are not aware, however, of any report studying this diaschisis by means of the method of magnetic resonance imaging (MRI). In this connection, we studied brain MRI in 38 patients with cerebral infarctions. The T 1 relaxation time was estimated in the white and grey matters of the frontal, temporal, and occipital lobes and the thalamus, including the cerebral white matter of both the infarct and non-infarct sides. In the major-stroke group, significant increases (all P 1 relaxation time were observed in the thalamus of the infarct side, as well as in the thalamus and the white matter of the occipital lobe on the non-infarct side. In the minor-stroke group, significant increases (all P 1 relaxation time were also observed in all areas except the frontal-lobe white matter of the infarct and non-infarct sides. We have thus proved the presence of diaschisis through the method of MRI by evaluating the T 1 relaxation time. An analysis of the time profile of the T 1 relaxation time in each area demonstrated that the T 1 relaxation time tended to show its greatest value between 2 weeks and 2 months and thereafter gradually decreased, reaching the normal range 2 months later in the white matter of both the infarct and non-infarct sides. The T 1 relaxation time in the thalamus of the infarct side, however, decreased between 2 weeks and 2 months and then increased again. Therefore, we were able to show different time profiles of the diaschisis in various areas of the brain through the analysis of the T 1 relaxation time in MRI. (author)

  12. CVD transfer-free graphene for sensing applications.

    Science.gov (United States)

    Schiattarella, Chiara; Vollebregt, Sten; Polichetti, Tiziana; Alfano, Brigida; Massera, Ettore; Miglietta, Maria Lucia; Di Francia, Girolamo; Sarro, Pasqualina Maria

    2017-01-01

    The sp 2 carbon-based allotropes have been extensively exploited for the realization of gas sensors in the recent years because of their high conductivity and large specific surface area. A study on graphene that was synthetized by means of a novel transfer-free fabrication approach and is employed as sensing material is herein presented. Multilayer graphene was deposited by chemical vapour deposition (CVD) mediated by CMOS-compatible Mo. The utilized technique takes advantage of the absence of damage or contamination of the synthesized graphene, because there is no need for the transfer onto a substrate. Moreover, a proper pre-patterning of the Mo catalyst allows one to obtain graphene films with different shapes and dimensions. The sensing properties of the material have been investigated by exposing the devices to NO 2 , NH 3 and CO, which have been selected because they are well-known hazardous substances. The concentration ranges have been chosen according to the conventional monitoring of these gases. The measurements have been carried out in humid N 2 environment, setting the flow rate at 500 sccm, the temperature at 25 °C and the relative humidity (RH) at 50%. An increase of the conductance response has been recorded upon exposure towards NO 2 , whereas a decrease of the signal has been detected towards NH 3 . The material appears totally insensitive towards CO. Finally, the sensing selectivity has been proven by evaluating and comparing the degree of adsorption and the interaction energies for NO 2 and NH 3 on graphene. The direct-growth approach for the synthesis of graphene opens a promising path towards diverse applicative scenarios, including the straightforward integration in electronic devices.

  13. Chemical vapor deposition (CVD) of uranium for alpha spectrometry

    International Nuclear Information System (INIS)

    Ramirez V, M. L.; Rios M, C.; Ramirez O, J.; Davila R, J. I.; Mireles G, F.

    2015-09-01

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  14. Lithium storage properties of multiwall carbon nanotubes prepared by CVD

    International Nuclear Information System (INIS)

    Ahn, J.-O.; Andong National University,; Wang, G.X.; Liu, H.K.; Dou, S.X.

    2003-01-01

    Full text: Multiwall carbon nanotubes (MWCNTs) were synthesised by chemical vapour deposition (CVD) method using acetylene gas. The XRD pattern of as prepared carbon nanotubes showed that the d 002 value is 3.44 Angstroms. The morphology and microstructure of carbon nanotubes were characterized by HRTEM. Most of carbon nanotubes are entangled together to form bundles or ropes. The diameter of the carbon nanotubes is in the range of 10 ∼ 20 nm. There is a small amount of amorphous carbon particles presented in the sample. However, the yield of carbon nanotubes is more than 95%. Electrochemical properties of carbon nanotubes were characterised via a variety of electrochemical testing techniques. The result of CV test showed that the Li insertion potential is quite low, which is very close to O V versus Li + /Li reference electrode, whereas the potential for Li de-intercalation is in the range of 0.2-0.4 V. There exists a slight voltage hysteresis between Li intercalation and Li de-intercalation, which is similar to the other carbonaceous materials. The intensity of redox peaks of carbon nanotubes decrease with scanning cycle, indicating that the reversible Li insertion capacity gradually decreases. The carbon nanotubes electrode demonstrated a reversible lithium storage capacity of 340 mAh/g with good cyclability at moderate current density. Further improvement of Li storage capacity is possible by opening the end of carbon nanotubes to allow lithium insertion into inner graphene sheet of carbon nanotubes. The kinetic properties of lithium insertion in carbon nanotube electrodes were characterised by a.c. impedance measurements. It was found that the lithium diffusion coefficient d Li decreases with an increase of Li ion concentration in carbon nanotube host

  15. Selective CVD tungsten on silicon implanted SiO/sub 2/

    International Nuclear Information System (INIS)

    Hennessy, W.A.; Ghezzo, M.; Wilson, R.H.; Bakhru, H.

    1988-01-01

    The application range of selective CVD tungsten is extended by its coupling to the ion implantation of insulating materials. This article documents the results of selective CVD tungsten using silicon implanted into SiO/sub 2/ to nucleate the tungsten growth. The role of implant does, energy, and surface preparation in achieving nucleation are described. SEM micrographs are presented to demonstrate the selectivity of this process. Measurements of the tungsten film thickness and sheet resistance are provided for each of the experimental variants corresponding to successful deposition. RBS and XPS analysis are discussed in terms of characterizing the tungsten/oxide interface and to evaluate the role of the silicon implant in the CVD tungsten mechanism. Utilizing this method a desired metallization pattern can be readily defined with lithography and ion implantation, and accurately replicated with a layer of CVD tungsten. This approach avoids problems usually associated with blanket deposition and pattern transfer, which are particularly troublesome for submicron VLSI technology

  16. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kalam, Amir Abul; Bae, Joon Ho [Dept. of Nano-physics, Gachon University, Seongnam (Korea, Republic of); Park, Soo Bin; Seo, Yong Ho [Nanotechnology and Advanced Material Engineering, HMC, and GRI, Sejong University, Seoul (Korea, Republic of)

    2015-08-15

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs.

  17. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Kalam, Amir Abul; Bae, Joon Ho; Park, Soo Bin; Seo, Yong Ho

    2015-01-01

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs

  18. Deposition and micro electrical discharge machining of CVD-diamond layers incorporated with silicon

    Science.gov (United States)

    Kühn, R.; Berger, T.; Prieske, M.; Börner, R.; Hackert-Oschätzchen, M.; Zeidler, H.; Schubert, A.

    2017-10-01

    In metal forming, lubricants have to be used to prevent corrosion or to reduce friction and tool wear. From an economical and ecological point of view, the aim is to avoid the usage of lubricants. For dry deep drawing of aluminum sheets it is intended to apply locally micro-structured wear-resistant carbon based coatings onto steel tools. One type of these coatings are diamond layers prepared by chemical vapor deposition (CVD). Due to the high strength of diamond, milling processes are unsuitable for micro-structuring of these layers. In contrast to this, micro electrical discharge machining (micro EDM) is a suitable process for micro-structuring CVD-diamond layers. Due to its non-contact nature and its process principle of ablating material by melting and evaporating, it is independent of the hardness, brittleness or toughness of the workpiece material. In this study the deposition and micro electrical discharge machining of silicon incorporated CVD-diamond (Si-CVD-diamond) layers were presented. For this, 10 µm thick layers were deposited on molybdenum plates by a laser-induced plasma CVD process (LaPlas-CVD). For the characterization of the coatings RAMAN- and EDX-analyses were conducted. Experiments in EDM were carried out with a tungsten carbide tool electrode with a diameter of 90 µm to investigate the micro-structuring of Si-CVD-diamond. The impact of voltage, discharge energy and tool polarity on process speed and resulting erosion geometry were analyzed. The results show that micro EDM is a suitable technology for micro-structuring of silicon incorporated CVD-diamond layers.

  19. Bone repair after osteotomy with diamond burs and CVD ultrasonic tips – histological study in rats

    OpenAIRE

    Matuda, Fábio S.; Pagani, Clovis; Miranda, Carolina B.; Crema, Aline A. S.; Brentel, Aline S.; Carvalho, Yasmin R.

    2010-01-01

    This study histologically evaluated the behavior of bone tissue of rats submitted to osteotomy with conventional diamond burs in high speed and a new ultrasonic diamond tips system (CVD – Chemical Vapor Deposition), at different study periods. The study was conducted on 24 Wistar rats. Osteotomy was performed on the posterior paws of each rat, with utilization of diamond burs in high speed under thorough water cooling at the right paw, and CVD tips at the left paw. Animals were killed a...

  20. Simulation of a perfect CVD diamond Schottky diode steep forward current–voltage characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Kukushkin, V.A., E-mail: vakuk@appl.sci-nnov.ru [Institute of Applied Physics of the Russian Academy of Science, 46 Ulyanov St., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State University named after N.I. Lobachevsky, 23 Gagarin pr., 603950 Nizhny Novgorod (Russian Federation)

    2016-10-01

    The kinetic equation approach to the simulation of the perfect CVD diamond Schottky diode current–voltage characteristic is considered. In result it is shown that the latter has a significantly steeper forward branch than that of perfect devices of such a type on usual semiconductors. It means that CVD diamond-based Schottky diodes have an important potential advantage over analogous devices on conventional materials.

  1. Tribological Characteristics and Applications of Superhard Coatings: CVD Diamond, DLC, and c-BN

    Science.gov (United States)

    Miyoshi, Kazuhisa; Murakawa, Masao; Watanabe, Shuichi; Takeuchi, Sadao; Wu, Richard L. C.

    1999-01-01

    Results of fundamental research on the tribological properties of chemical-vapor-deposited (CVD) diamond, diamondlike carbon, and cubic boron nitride films in sliding contact with CVD diamond in ultrahigh vacuum, dry nitrogen, humid air, and water are discussed. Furthermore, the actual and potential applications of the three different superhard coatings in the field of tribology technology, particularly for wear parts and tools, are reviewed.

  2. CVD Diamond, DLC, and c-BN Coatings for Solid Film Lubrication

    Science.gov (United States)

    Miyoshi, Kazuhisa

    1998-01-01

    When the main criteria for judging coating performance were coefficient of friction and wear rate, which had to be less than 0.1 and 10(exp -6) mm(exp 3)/N-m, respectively, carbon- and nitrogen-ion-implanted, fine-grain CVD diamond and DLC ion beam deposited on fine-grain CVD diamond met the requirements regardless of environment (vacuum, nitrogen, and air).

  3. Defining the relationship between COPD and CVD: what are the implications for clinical practice?

    Science.gov (United States)

    Morgan, Ann D; Zakeri, Rosita; Quint, Jennifer K

    2018-01-01

    Cardiovascular diseases (CVDs) are arguably the most important comorbidities in chronic obstructive pulmonary disease (COPD). CVDs are common in people with COPD, and their presence is associated with increased risk for hospitalization, longer length of stay and all-cause and CVD-related mortality. The economic burden associated with CVD in this population is considerable and the cumulative cost of treating comorbidities may even exceed that of treating COPD itself. Our understanding of the biological mechanisms that link COPD and various forms of CVD has improved significantly over the past decade. But despite broad acceptance of the prognostic significance of CVDs in COPD, there remains widespread under-recognition and undertreatment of comorbid CVD in this population. The reasons for this are unclear; however institutional barriers and a lack of evidence-based guidelines for the management of CVD in people with COPD may be contributory factors. In this review, we summarize current knowledge relating to the prevalence and incidence of CVD in people with COPD and the mechanisms that underlie their coexistence. We discuss the implications for clinical practice and highlight opportunities for improved prevention and treatment of CVD in people with COPD. While we advocate more active assessment for signs of cardiovascular conditions across all age groups and all stages of COPD severity, we suggest targeting those aged under 65 years. Evidence indicates that the increased risks for CVD are particularly pronounced in COPD patients in mid-to-late-middle-age and thus it is in this age group that the benefits of early intervention may prove to be the most effective. PMID:29355081

  4. Chemical vapor deposition (CVD) of uranium for alpha spectrometry; Deposicion quimica de vapor (CVD) de uranio para espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez V, M. L.; Rios M, C.; Ramirez O, J.; Davila R, J. I.; Mireles G, F., E-mail: luisalawliet@gmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2015-09-15

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  5. Surface structuring of boron doped CVD diamond by micro electrical discharge machining

    Science.gov (United States)

    Schubert, A.; Berger, T.; Martin, A.; Hackert-Oschätzchen, M.; Treffkorn, N.; Kühn, R.

    2018-05-01

    Boron doped diamond materials, which are generated by Chemical Vapor Deposition (CVD), offer a great potential for the application on highly stressed tools, e. g. in cutting or forming processes. As a result of the CVD process rough surfaces arise, which require a finishing treatment in particular for the application in forming tools. Cutting techniques such as milling and grinding are hardly applicable for the finish machining because of the high strength of diamond. Due to its process principle of ablating material by melting and evaporating, Electrical Discharge Machining (EDM) is independent of hardness, brittleness or toughness of the workpiece material. EDM is a suitable technology for machining and structuring CVD diamond, since boron doped CVD diamond is electrically conductive. In this study the ablation characteristics of boron doped CVD diamond by micro electrical discharge machining are investigated. Experiments were carried out to investigate the influence of different process parameters on the machining result. The impact of tool-polarity, voltage and discharge energy on the resulting erosion geometry and the tool wear was analyzed. A variation in path overlapping during the erosion of planar areas leads to different microstructures. The results show that micro EDM is a suitable technology for finishing of boron doped CVD diamond.

  6. A Hybrid Information Mining Approach for Knowledge Discovery in Cardiovascular Disease (CVD

    Directory of Open Access Journals (Sweden)

    Stefania Pasanisi

    2018-04-01

    Full Text Available The healthcare ambit is usually perceived as “information rich” yet “knowledge poor”. Nowadays, an unprecedented effort is underway to increase the use of business intelligence techniques to solve this problem. Heart disease (HD is a major cause of mortality in modern society. This paper analyzes the risk factors that have been identified in cardiovascular disease (CVD surveillance systems. The Heart Care study identifies attributes related to CVD risk (gender, age, smoking habit, etc. and other dependent variables that include a specific form of CVD (diabetes, hypertension, cardiac disease, etc.. In this paper, we combine Clustering, Association Rules, and Neural Networks for the assessment of heart-event-related risk factors, targeting the reduction of CVD risk. With the use of the K-means algorithm, significant groups of patients are found. Then, the Apriori algorithm is applied in order to understand the kinds of relations between the attributes within the dataset, first looking within the whole dataset and then refining the results through the subsets defined by the clusters. Finally, both results allow us to better define patients’ characteristics in order to make predictions about CVD risk with a Multilayer Perceptron Neural Network. The results obtained with the hybrid information mining approach indicate that it is an effective strategy for knowledge discovery concerning chronic diseases, particularly for CVD risk.

  7. Recent Results from Beam Tests of 3D and Pad pCVD Diamond Detectors

    CERN Document Server

    Wallny, Rainer

    2017-01-01

    Results from prototypes of a detector using chemical vapor deposited (CVD) diamond with embedded resistive electrodes in the bulk forming a 3D diamond device are presented. A detector system consisting of 3D devices based on poly-crystalline CVD (pCVD) diamond was connected to a multi-channel readout and successfully tested in a 120 GeV/c proton beam at CERN proving for the first time the feasibility of the 3D detector concept in pCVD for particle tracking applications. We also present beam test results on the dependence of signal size on incident particle rate in charged particle detectors based on poly-crystalline CVD diamond. The detectors were tested in a 260 MeV/c pion beam over a range of particle fluxes from 2 kHz/cm2 to 10 MHz/cm2 . The pulse height of the sensors was measured with pad readout electronics at a peaking time of 7 ns. Our data from the 2015 beam tests at PSI indicate that the pulse height of poly-crystalline CVD diamond sensor irradiated to 5×1014 neq/cm2 is independent of particle flux...

  8. Ion beam induced surface graphitization of CVD diamond for x-ray beam position monitor applications

    International Nuclear Information System (INIS)

    Liu, Chian; Shu, D.; Kuzay, T.M.; Wen, L.; Melendres, C.A.; Argonne National Lab., IL

    1996-01-01

    The Advanced Photon Source at ANL is a third-generation synchrotron facility that generates powerful x-ray beams on its undulator beamlines. It is important to know the position and angle of the x- ray beam during experiments. Due to very high heat flux levels, several patented x-ray beam position monitors (XBPM) exploiting chemical vapor deposition (CVD) diamond have been developed. These XBPMs have a thin layer of low-atomic-mass metallic coating so that photoemission from the x rays generate a minute but measurable current for position determination. Graphitization of the CVD diamond surface creates a very thin, intrinsic and conducting layer that can stand much higher temperatures and minimal x-ray transmission losses compared to the coated metallic layers. In this paper, a laboratory sputter ion source was used to transform selected surfaces of a CVD diamond substrate into graphite. The effect of 1-5 keV argon ion bombardment on CVD diamond surfaces at various target temperatures from 200 to 500 C was studied using Auger electron spectroscopy and in-situ electrical resistivity measurements. Graphitization after the ion bombardment has been confirmed and optimum conditions for graphitization studied. Raman spectroscopy was used to identify the overall diamond structure in the bulk of CVD diamond substrate after the ion bombardments. It was found that target temperature plays an important role in stability and electrical conductivity of the irradiated CVD diamonds

  9. AVALIAÇÃO DA COMPATIBILIDADE DA ENXERTIA EM Prunus sp. EVALUATION OF THE GRAFT COMPATIBILITY IN Prunus sp.

    Directory of Open Access Journals (Sweden)

    ALEXANDRE COUTO RODRIGUES

    2001-08-01

    Full Text Available A atividade de peroxidase e concentração de fenóis foi determinada com o objetivo de se avaliar aspectos de compatibilidade entre porta-enxertos e enxertos. As amostras foram processadas e obtidas a partir da casca e lenho dos porta-enxertos de pessegueiros (GF 677, Okinawa, Capdeboscq e Aldrighi e de ameixeiras (Mirabolano e Marianna, enxertados ou não com as cultivares Diamante, Eldorado e Santa Rosa. Concluiu-se que a atividade de peroxidase e a concentração de fenóis foram relacionadas com união entre enxerto e porta-enxerto, particularmente, em Marianna e Mirabolano, onde a atividade de peroxidase e a concentração de fenóis foram mais elevados. A cultivar Santa Rosa foi compatível tanto com os porta-enxertos de ameixeiras quanto com os de pessegueiros.The work was accomplished aiming to quantify the peroxidase activity and total phenols, in order to verify the physiological and biochemical processes in grafting of Prunus sp. cultivars. The samples were processed and obtained in bark and wood of the peach rootstocks (GF 677, Okinawa, Capdeboscq and Aldrighi and plum rootstocks (Mirabolano and Marianna, after they had or not been grafted with the stock Diamante, Eldorado and Santa Rosa. It could be concluded that the peroxidase and the total phenols activity influenced the union between stock and rootstock; after grafting, the incompatibility degree is related with high peroxidase activity and total phenols in the rootstock Marianna and Mirabolano. The Santa Rosa plum graft is as compatible to plum rootstocks as to the peach ones.

  10. Cardiovascular disease (CVD) and chronic kidney disease (CKD) event rates in HIV-positive persons at high predicted CVD and CKD risk

    DEFF Research Database (Denmark)

    Boyd, Mark A; Mocroft, Amanda; Ryom, Lene

    2017-01-01

    BACKGROUND: The Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study has developed predictive risk scores for cardiovascular disease (CVD) and chronic kidney disease (CKD, defined as confirmed estimated glomerular filtration rate [eGFR] ≤ 60 ml/min/1.73 m2) events in HIV...

  11. How dietary evidence for the prevention and treatment of CVD is translated into practice in those with or at high risk of CVD: a systematic review.

    Science.gov (United States)

    Schumacher, Tracy L; Burrows, Tracy L; Neubeck, Lis; Redfern, Julie; Callister, Robin; Collins, Clare E

    2017-01-01

    CVD is a leading cause of mortality and morbidity, and nutrition is an important lifestyle factor. The aim of the present systematic review was to synthesise the literature relating to knowledge translation (KT) of dietary evidence for the prevention and treatment of CVD into practice in populations with or at high risk of CVD. A systematic search of six electronic databases (CINAHL, Cochrane, EMBASE, MEDLINE, PsycINFO and Scopus) was performed. Studies were included if a nutrition or dietary KT was demonstrated to occur with a relevant separate measureable outcome. Quality was assessed using a tool adapted from two quality checklists. Population with or at high risk of CVD or clinicians likely to treat this population. A total of 4420 titles and abstracts were screened for inclusion, with 354 full texts retrieved to assess inclusion. Forty-three articles were included in the review, relating to thirty-five separate studies. No studies specifically stated their aim to be KT. Thirty-one studies were in patient or high-risk populations and four targeted health professionals. Few studies stated a theory on which the intervention was based (n 10) and provision of instruction was the most common behaviour change strategy used (n 26). KT in nutrition and dietary studies has been inferred, not stated, with few details provided regarding how dietary knowledge is translated to the end user. This presents challenges for implementation by clinicians and policy and decision makers. Consequently a need exists to improve the quality of publications in this area.

  12. Friction Properties of Polished Cvd Diamond Films Sliding against Different Metals

    Science.gov (United States)

    Lin, Zichao; Sun, Fanghong; Shen, Bin

    2016-11-01

    Owing to their excellent mechanical and tribological properties, like the well-known extreme hardness, low coefficient of friction and high chemical inertness, chemical vapor deposition (CVD) diamond films have found applications as a hard coating for drawing dies. The surface roughness of the diamond films is one of the most important attributes to the drawing dies. In this paper, the effects of different surface roughnesses on the friction properties of diamond films have been experimentally studied. Diamond films were fabricated using hot filament CVD. The WC-Co (Co 6wt.%) drawing dies were used as substrates. A gas mixture of acetone and hydrogen gas was used as the feedstock gas. The CVD diamond films were polished using mechanical polishing. Polished diamond films with three different surface roughnesses, as well as the unpolished diamond film, were fabricated in order to study the tribological performance between the CVD diamond films and different metals with oil lubrication. The unpolished and polished CVD diamond films are characterized with scanning electron microscope (SEM), atomic force microscope (AFM), surface profilometer, Raman spectrum and X-ray diffraction (XRD). The friction examinations were carried out by using a ball-on-plate type reciprocating friction tester. Low carbide steel, stainless steel, copper and aluminum materials were used as counterpart balls. Based on this study, the results presented the friction coefficients between the polished CVD films and different metals. The friction tests demonstrate that the smooth surface finish of CVD diamond films is beneficial for reducing their friction coefficients. The diamond films exhibit low friction coefficients when slid against the stainless steel balls and low carbide steel ball, lower than that slid against copper ball and aluminum ball, attributed to the higher ductility of copper and aluminum causing larger amount of wear debris adhering to the sliding interface and higher adhesive

  13. Cardiovascular disease (CVD and chronic kidney disease (CKD event rates in HIV-positive persons at high predicted CVD and CKD risk: A prospective analysis of the D:A:D observational study.

    Directory of Open Access Journals (Sweden)

    Mark A Boyd

    2017-11-01

    Full Text Available The Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D study has developed predictive risk scores for cardiovascular disease (CVD and chronic kidney disease (CKD, defined as confirmed estimated glomerular filtration rate [eGFR] ≤ 60 ml/min/1.73 m2 events in HIV-positive people. We hypothesized that participants in D:A:D at high (>5% predicted risk for both CVD and CKD would be at even greater risk for CVD and CKD events.We included all participants with complete risk factor (covariate data, baseline eGFR > 60 ml/min/1.73 m2, and a confirmed (>3 months apart eGFR 1%-5%, >5% and fitted Poisson models to assess whether CVD and CKD risk group effects were multiplicative. A total of 27,215 participants contributed 202,034 person-years of follow-up: 74% male, median (IQR age 42 (36, 49 years, median (IQR baseline year of follow-up 2005 (2004, 2008. D:A:D risk equations predicted 3,560 (13.1% participants at high CVD risk, 4,996 (18.4% participants at high CKD risk, and 1,585 (5.8% participants at both high CKD and high CVD risk. CVD and CKD event rates by predicted risk group were multiplicative. Participants at high CVD risk had a 5.63-fold (95% CI 4.47, 7.09, p < 0.001 increase in CKD events compared to those at low risk; participants at high CKD risk had a 1.31-fold (95% CI 1.09, 1.56, p = 0.005 increase in CVD events compared to those at low risk. Participants' CVD and CKD risk groups had multiplicative predictive effects, with no evidence of an interaction (p = 0.329 and p = 0.291 for CKD and CVD, respectively. The main study limitation is the difference in the ascertainment of the clinically defined CVD endpoints and the laboratory-defined CKD endpoints.We found that people at high predicted risk for both CVD and CKD have substantially greater risks for both CVD and CKD events compared with those at low predicted risk for both outcomes, and compared to those at high predicted risk for only CVD or CKD events. This suggests that CVD and

  14. Movers and stayers: The geography of residential mobility and CVD hospitalisations in Auckland, New Zealand.

    Science.gov (United States)

    Exeter, Daniel J; Sabel, Clive E; Hanham, Grant; Lee, Arier C; Wells, Susan

    2015-05-01

    The association between area-level disadvantage and health and social outcomes is unequivocal. However, less is known about the health impact of residential mobility, particularly at intra-urban scales. We used an encrypted National Health Index (eNHI) number to link individual-level data recorded in routine national health databases to construct a cohort of 641,532 participants aged 30+ years to investigate the association between moving and CVD hospitalisations in Auckland, New Zealand. Residential mobility was measured for participants according to changes in the census Meshblock of usual residence, obtained from the Primary Health Organisation (PHO) database for every calendar quarter between 1/1/2006 and 31/12/2012. The NZDep2006 area deprivation score at the start and end of a participant's inclusion in the study was used to measure deprivation mobility. We investigated the relative risk of movers being hospitalised for CVD relative to stayers using multi-variable binomial regression models, controlling for age, gender, deprivation and ethnicity. Considered together, movers were 1.22 (1.19-1.26) times more likely than stayers to be hospitalised for CVD. Using the 5×5 deprivation origin-destination matrix to model a patient's risk of CVD based on upward, downward or sideways deprivation mobility, movers within the least deprived (NZDep2006 Quintile 1) areas were 10% less likely than stayers to be hospitalised for CVD, while movers within the most deprived (NZDep2006 Q5) areas were 45% more likely than stayers to have had their first CVD hospitalisation in 2006-2012 (RR: 1.45 [1.35-1.55]). Participants who moved upward also had higher relative risks of having a CVD event, although their risk was less than those observed for participants experiencing downward deprivation mobility. This research suggests that residential mobility is an important determinant of CVD in Auckland. Further investigation is required to determine the impact moving has on the risk of

  15. Rapid growth of single-layer graphene on the insulating substrates by thermal CVD

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y. [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Dai, D.; Chen, G.X.; Yu, J.H. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Nishimura, K. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Advanced Nano-processing Engineering Lab, Mechanical Systems Engineering, Kogakuin University (Japan); Lin, C.-T. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Jiang, N., E-mail: jiangnan@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhan, Z.L., E-mail: zl_zhan@sohu.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2015-08-15

    Highlights: • A rapid thermal CVD process has been developed to directly grow graphene on the insulating substrates. • The treating time consumed is ≈25% compared to conventional CVD procedure. • Single-layer and few-layer graphene can be formed on quartz and SiO{sub 2}/Si substrates, respectively. • The formation of thinner graphene at the interface is due to the fast precipitation rate of carbon atoms during cooling. - Abstract: The advance of CVD technique to directly grow graphene on the insulating substrates is particularly significant for further device fabrication. As graphene is catalytically grown on metal foils, the degradation of the sample properties is unavoidable during transfer of graphene on the dielectric layer. Moreover, shortening the treatment time as possible, while achieving single-layer growth of graphene, is worthy to be investigated for promoting the efficiency of mass production. Here we performed a rapid heating/cooling process to grow graphene films directly on the insulating substrates by thermal CVD. The treating time consumed is ≈25% compared to conventional CVD procedure. In addition, we found that high-quality, single-layer graphene can be formed on quartz, but on SiO{sub 2}/Si substrate only few-layer graphene can be obtained. The pronounced substrate effect is attributed to the different dewetting behavior of Ni films on the both substrates at 950 °C.

  16. Applicability of the Existing CVD Risk Assessment Tools to Type II Diabetics in Oman: A Review

    Directory of Open Access Journals (Sweden)

    Abdulhakeem Al-Rawahi

    2015-09-01

    Full Text Available Patients with type II diabetes (T2DM have an elevated risk for cardiovascular disease (CVD, and it is considered to be a leading cause of morbidity and premature mortality in these patients. Many traditional risk factors such as age, male sex, hypertension, dyslipidemia, glycemic control, diabetes duration, renal dysfunction, obesity, and smoking have been studied and identified as independent factors for CVD. Quantifying the risk of CVD among diabetics using the common risk factors in order to plan the treatment and preventive measures is important in the management of these patients as recommended by many clinical guidelines. Therefore, several risk assessment tools have been developed in different parts of the world for this purpose. These include the tools that have been developed for general populations and considered T2DM as a risk factor, and the tools that have been developed for T2DM populations specifically. However, due to the differences in sociodemographic factors and lifestyle patterns, as well as the differences in the distribution of various CVD risk factors in different diabetic populations, the external applicability of these tools on different populations is questionable. This review aims to address the applicability of the existing CVD risk models to the Omani diabetic population.

  17. Reference Intervals for Non-Fasting CVD Lipids and Inflammation Markers in Pregnant Indigenous Australian Women.

    Science.gov (United States)

    Schumacher, Tracy L; Oldmeadow, Christopher; Clausen, Don; Weatherall, Loretta; Keogh, Lyniece; Pringle, Kirsty G; Rae, Kym M

    2017-10-14

    Indigenous Australians experience high rates of cardiovascular disease (CVD). The origins of CVD may commence during pregnancy, yet few serum reference values for CVD biomarkers exist specific to the pregnancy period. The Gomeroi gaaynggal research project is a program that undertakes research and provides some health services to pregnant Indigenous women. Three hundred and ninety-nine non-fasting samples provided by the study participants (206 pregnancies and 175 women) have been used to construct reference intervals for CVD biomarkers during this critical time. A pragmatic design was used, in that women were not excluded for the presence of chronic or acute health states. Percentile bands for non-linear relationships were constructed according to the methods of Wright and Royston (2008), using the xriml package in StataIC 13.1. Serum cholesterol, triglycerides, cystatin-C and alkaline phosphatase increased as gestational age progressed, with little change seen in high-sensitivity C-Reactive Protein and γ glutamyl transferase. Values provided in the reference intervals are consistent with findings from other research projects. These reference intervals will form a basis with which future CVD biomarkers for pregnant Indigenous Australian women can be compared.

  18. Spin transport in two-layer-CVD-hBN/graphene/hBN heterostructures

    Science.gov (United States)

    Gurram, M.; Omar, S.; Zihlmann, S.; Makk, P.; Li, Q. C.; Zhang, Y. F.; Schönenberger, C.; van Wees, B. J.

    2018-01-01

    We study room-temperature spin transport in graphene devices encapsulated between a layer-by-layer-stacked two-layer-thick chemical vapor deposition (CVD) grown hexagonal boron nitride (hBN) tunnel barrier, and a few-layer-thick exfoliated-hBN substrate. We find mobilities and spin-relaxation times comparable to that of SiO2 substrate-based graphene devices, and we obtain a similar order of magnitude of spin relaxation rates for both the Elliott-Yafet and D'Yakonov-Perel' mechanisms. The behavior of ferromagnet/two-layer-CVD-hBN/graphene/hBN contacts ranges from transparent to tunneling due to inhomogeneities in the CVD-hBN barriers. Surprisingly, we find both positive and negative spin polarizations for high-resistance two-layer-CVD-hBN barrier contacts with respect to the low-resistance contacts. Furthermore, we find that the differential spin-injection polarization of the high-resistance contacts can be modulated by dc bias from -0.3 to +0.3 V with no change in its sign, while its magnitude increases at higher negative bias. These features point to the distinctive spin-injection nature of the two-layer-CVD-hBN compared to the bilayer-exfoliated-hBN tunnel barriers.

  19. Effect of pulse biasing on the morphology of diamond films grown by hot filament CVD

    International Nuclear Information System (INIS)

    Beake, B.D.; Hussain, I.U.; Rego, C.; Ahmed, W.

    1999-01-01

    There has been considerable interest in the chemical vapour deposition (CVD) of diamond due to its unique mechanical, optical and electronic properties, which make it useful for many applications. For use in optical and electronic applications further developments in the CVD process are required to control the surface morphology and crystal size of the diamond films. These will require a detailed understanding of both the nucleation and growth processes that effect the properties. The technique of bias enhanced nucleation (BEN) of diamond offers better reproducibility than conventional pre-treatment methods such as mechanical abrasion. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) have been used study the surface modification of diamond films on silicon substrates during pulse biased growth in a hot filament CVD reactor. Pre-abraded silicon substrates were subjected to a three-step sequential growth process: (i) diamond deposition under standard CVD conditions, (ii) bias pre-treatment and (iii) deposition under standard conditions. The results show that the bias pre-treatment time is a critical parameter controlling the surface morphology and roughness of the diamond films deposited. Biasing reduces the surface roughness from 152 nm for standard CVD diamond to 68 nm for the 2.5 minutes pulse biased film. Further increase in the bias time results in an increase in surface roughness and crystallite size. (author)

  20. Flavonoids and Reduction of Cardiovascular Disease (CVD) in Chronic Obstructive Pulmonary Disease (COPD).

    Science.gov (United States)

    Russo, Patrizia; Prinzi, Giulia; Lamonaca, Palma; Cardaci, Vittorio; Fini, Massimo

    2018-05-13

    Chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CV) often coexist. COPD and CVD are complex diseases characterized by a strict interaction between environment and genetic. The mechanisms linking these two diseases are complex, multifactorial and not entirely understood, influencing the therapeutic approach. COPD is characterized by several comorbidities, it is hypothesizable that treatment of cardiovascular co-morbidities may reduce morbidity and mortality. Flavonoids are an important class of plant low molecular weight secondary metabolites (SMs). Convincing data from laboratory, epidemiological, and human clinical studies point to an important effects on CVD risk prevention. This review aims to provide up-to-date information on the ability of Flavonoids to reduce the CVD risk. Current studies support the potential of Flavonoids to prevent the risk of CVD. Well-designed clinical studies are suggested to evaluate advantages and limits of Flavonoids for managing CVD comorbidity in COPD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. High quality aluminide and thermal barrier coatings deposition for new and service exposed parts by CVD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza, F.; Tuohy, C.; Whelan, L.; Kennedy, A.D. [SIFCO Turbine Components, Carrigtwohill, Cork (Ireland)

    2004-07-01

    In this work, the performance of CVD aluminide coatings is compared to that of coatings deposited by the classical pack cementation technique using standard SIFCO procedures. The CVD coatings always seem to behave better upon exposure to isothermal and cyclic oxidation conditions. This is explained by a longer term stability of CVD coatings, with higher Al amounts in the diffusion zone and less refractory element precipitation in the additive layer. The qualities of Pt/Al coatings by out-of-pack and CVD are also compared as a previous step for further thermal barrier coating deposition. As an example, YSZ thermal barrier coatings are deposited by MO-CVD on Pt/Al CVD bond coats rendering adherent and thick coatings around the surface of turbine blades. This process under development does not require complex manipulation of the component to be coated. (orig.)

  2. Electrical characteristics of thermal CVD B-doped Si films on highly strained Si epitaxially grown on Ge(100) by plasma CVD without substrate heating

    International Nuclear Information System (INIS)

    Sugawara, Katsutoshi; Sakuraba, Masao; Murota, Junichi

    2010-01-01

    Using an 84% relaxed Ge(100) buffer layer formed on Si(100) by electron cyclotron resonance (ECR) plasma enhanced chemical vapor deposition (CVD), influence of strain upon electrical characteristics of B-doped Si film epitaxially grown on the Ge buffer have been investigated. For the thinner B-doped Si film, surface strain amount is larger than that of the thicker film, for example, strain amount reaches 2.0% for the thickness of 2.2 nm. It is found that the hole mobility is enhanced by the introduction of strain to Si, and the maximum enhancement of about 3 is obtained. This value is higher than that of the usually reported mobility enhancement by strain using Si 1 -x Ge x buffer. Therefore, introduction of strain using relaxed Ge film formed by ECR plasma enhanced CVD is useful to improve future Si-based device performance.

  3. Non-classical crystallization of thin films and nanostructures in CVD and PVD processes

    CERN Document Server

    Hwang, Nong Moon

    2016-01-01

    This book provides a comprehensive introduction to a recently-developed approach to the growth mechanism of thin films and nanostructures via chemical vapour deposition (CVD). Starting from the underlying principles of the low pressure synthesis of diamond films, it is shown that diamond growth occurs not by individual atoms but by charged nanoparticles. This newly-discovered growth mechanism turns out to be general to many CVD and some physical vapor deposition (PVD) processes. This non-classical crystallization is a new paradigm of crystal growth, with active research taking place on growth in solution, especially in biomineralization processes. Established understanding of the growth of thin films and nanostructures is based around processes involving individual atoms or molecules. According to the author’s research over the last two decades, however, the generation of charged gas phase nuclei is shown to be the rule rather than the exception in the CVD process, and charged gas phase nuclei are actively ...

  4. Polymer Adsorption on Graphite and CVD Graphene Surfaces Studied by Surface-Specific Vibrational Spectroscopy.

    Science.gov (United States)

    Su, Yudan; Han, Hui-Ling; Cai, Qun; Wu, Qiong; Xie, Mingxiu; Chen, Daoyong; Geng, Baisong; Zhang, Yuanbo; Wang, Feng; Shen, Y R; Tian, Chuanshan

    2015-10-14

    Sum-frequency vibrational spectroscopy was employed to probe polymer contaminants on chemical vapor deposition (CVD) graphene and to study alkane and polyethylene (PE) adsorption on graphite. In comparing the spectra from the two surfaces, it was found that the contaminants on CVD graphene must be long-chain alkane or PE-like molecules. PE adsorption from solution on the honeycomb surface results in a self-assembled ordered monolayer with the C-C skeleton plane perpendicular to the surface and an adsorption free energy of ∼42 kJ/mol for PE(H(CH2CH2)nH) with n ≈ 60. Such large adsorption energy is responsible for the easy contamination of CVD graphene by impurity in the polymer during standard transfer processes. Contamination can be minimized with the use of purified polymers free of PE-like impurities.

  5. Cold Vacuum Dryer (CVD) Facility Fire Protection System Design Description (SYS 24)

    Energy Technology Data Exchange (ETDEWEB)

    SINGH, G.

    2000-10-17

    This system design description (SDD) addresses the Cold Vacuum Drying (CVD) Facility fire protection system (FPS). The primary features of the FPS for the CVD are a fire alarm and detection system, automatic sprinklers, and fire hydrants. The FPS also includes fire extinguishers located throughout the facility and fire hydrants to assist in manual firefighting efforts. In addition, a fire barrier separates the operations support (administrative) area from the process bays and process bay support areas. Administrative controls to limit combustible materials have been established and are a part of the overall fire protection program. The FPS is augmented by assistance from the Hanford Fire Department (HED) and by interface systems including service water, electrical power, drains, instrumentation and controls. This SDD, when used in conjunction with the other elements of the definitive design package, provides a complete picture of the FPS for the CVD Facility.

  6. Development of CVD Diamond for Industrial Applications Final Report CRADA No. TC-2047-02

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Olstad, R. [General Atomics, San Diego, CA (United States); Jory, H. [Communications and Power Industries, Palo Alto, CA (United States); Vikharov, A. L. [Russian Academy of Sciences (RAS), Moscow (Russian Federation)

    2017-09-08

    This project was a collaborative effort to develop and demonstrate a new millimeter microwave assisted chemical vapor deposition(CVD) process for manufacturing large diamond disks with greatly reduced processing times and costs from those now available. In the CVD process, carbon based gases (methane) and hydrogen are dissociated into plasma using microwave discharge and then deposited layer by layer as polycrystalline diamond onto a substrate. The available low frequency (2.45GHz) microwave sources used elsewhere (De Beers) result in low density plasmas and low deposition rates: 4 inch diamond disks take 6-8 weeks to process. The new system developed in this project uses a high frequency 30GHz Gyrotron as the microwave source and a quasi-optical CVD chamber resulting in a much higher density plasma which greatly reduced the diamond processing times (1-2 weeks)

  7. CVD diamond based soft X-ray detector with fast response

    International Nuclear Information System (INIS)

    Li Fang; Hou Lifei; Su Chunxiao; Yang Guohong; Liu Shenye

    2010-01-01

    A soft X-ray detector has been made with high quality chemical vapor deposited (CVD) diamond and the electrical structure of micro-strip. Through the measurement of response time on a laser with the pulse width of 10 ps, the full width at half maximum of the data got in the oscilloscope was 115 ps. The rise time of the CVD diamond detector was calculated to be 49 ps. In the experiment on the laser prototype facility, the signal got by the CVD diamond detector was compared with that got by a soft X-ray spectrometer. Both signals coincided well. The detector is proved to be a kind of reliable soft X-ray detector with fast response and high signal-to-noise ratio. (authors)

  8. Oxidation protection of multilayer CVD SiC/B/SiC coatings for 3D C/SiC composite

    International Nuclear Information System (INIS)

    Liu Yongsheng; Cheng Laifei; Zhang Litong; Wu Shoujun; Li Duo; Xu Yongdong

    2007-01-01

    A CVD boron coating was introduced between two CVD SiC coating layers. EDS and XRD results showed that the CVD B coating was a boron crystal without other impurity elements. SEM results indicated that the CVD B coating was a flake-like or column-like crystal with a compact cross-section. The crack width in the CVD SiC coating deposited on CVD B is smaller than that in a CVD SiC coating deposited on CVD SiC coating. After oxidation at 700 deg. C and 1000 deg. C, XRD results indicated that the coating was covered by product B 2 O 3 or B 2 O 3 .xSiO 2 film. The cracks were sealed as observed by SEM. There was a large amount of flake-like material on hybrid coating surface after oxidation at 1300 deg. C. Oxidation weight loss and residual flexural strength results showed that hybrid SiC/B/SiC multilayer coating provided better oxidation protection for C/SiC composite than a three layer CVD SiC coating at temperatures from 700 deg. C to 1000 deg. C for 600 min, but worse oxidation protection above 1000 deg. C due to the large amount of volatilization of B 2 O 3 or B 2 O 3 .xSiO 2

  9. Influence of surface morphology and microstructure on performance of CVD tungsten coating under fusion transient thermal loads

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Youyun, E-mail: lianyy@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Liu, Xiang; Wang, Jianbao; Feng, Fan [Southwestern Institute of Physics, Chengdu (China); Lv, Yanwei; Song, Jiupeng [China National R& D Center for Tungsten Technology, Xiamen Tungsten Co. Ltd, 361026 Xiamen (China); Chen, Jiming [Southwestern Institute of Physics, Chengdu (China)

    2016-12-30

    Highlights: • Thick CVD-W coatingswere deposited at a rapid growth rate. • The polished CVD-W coatings have highly textured structure and exhibited a very strong preferred orientation. • The polished CVD tungsten coatings show superior thermal shock resistance as compared with that of the as-deposited coatings. • The crack formation of the polished CVD-W was almost suppressed at an elevated temperature. - Abstract: Thick tungsten coatings have been deposited by chemical vapor deposition (CVD) at a rapid growth rate. A series of tungsten coatings with different thickness and surface morphology were prepared. The surface morphology, microstructure and preferred orientation of the CVD tungsten coatings were investigated. Thermal shock analyses were performed by using an electron beam facility to study the influence of the surface morphology and the microstructure on the thermal shock resistance of the CVD tungsten coatings. Repetitive (100 pulses) ELMs-like thermal shock loads were applied at various temperatures between room temperature and 600 °C with pulse duration of 1 ms and an absorbed power density of up to 1 GW/m{sup 2}. The results of the tests demonstrated that the specific surface morphology and columnar crystal structure of the CVD tungsten have significant influence on the surface cracking threshold and crack propagation of the materials. The CVD tungsten coatings with a polished surface show superior thermal shock resistance as compared with that of the as-deposited coatings with a rough surface.

  10. Association of BMI with risk of CVD mortality and all-cause mortality.

    Science.gov (United States)

    Kee, Chee Cheong; Sumarni, Mohd Ghazali; Lim, Kuang Hock; Selvarajah, Sharmini; Haniff, Jamaiyah; Tee, Guat Hiong Helen; Gurpreet, Kaur; Faudzi, Yusoff Ahmad; Amal, Nasir Mustafa

    2017-05-01

    To determine the relationship between BMI and risk of CVD mortality and all-cause mortality among Malaysian adults. Population-based, retrospective cohort study. Participants were followed up for 5 years from 2006 to 2010. Mortality data were obtained via record linkages with the Malaysian National Registration Department. Multiple Cox regression was applied to compare risk of CVD and all-cause mortality between BMI categories adjusting for age, gender and ethnicity. Models were generated for all participants, all participants the first 2 years of follow-up, healthy participants, healthy never smokers, never smokers, current smokers and former smokers. All fourteen states in Malaysia. Malaysian adults (n 32 839) aged 18 years or above from the third National Health and Morbidity Survey. Total follow-up time was 153 814 person-years with 1035 deaths from all causes and 225 deaths from CVD. Underweight (BMIBMI ≥30·0 kg/m2) was associated with a heightened risk of CVD mortality. Overweight (BMI=25·0-29·9 kg/m2) was inversely associated with risk of all-cause mortality. Underweight was significantly associated with all-cause mortality in all models except for current smokers. Overweight was inversely associated with all-cause mortality in all participants. Although a positive trend was observed between BMI and CVD mortality in all participants, a significant association was observed only for severe obesity (BMI≥35·0 kg/m2). Underweight was associated with increased risk of all-cause mortality and obesity with increased risk of CVD mortality. Therefore, maintaining a normal BMI through leading an active lifestyle and healthy dietary habits should continue to be promoted.

  11. Divergência genética em cultivares de morangueiro, baseada em caracteres morfoagronômicos

    Directory of Open Access Journals (Sweden)

    Rafael Gustavo Ferreira Morales

    2011-06-01

    Full Text Available Os caracteres morfoagronômicos são tradicionalmente usados na caracterização de cultivares e no estudo da divergência genética, contribuindo na definição de estratégias para o melhoramento genético. Este trabalho teve por objetivo avaliar a divergência genética por meio de caracteres morfoagronômicos de 11 cultivares de morangueiro (Aromas, Camarosa, Camino Real, Campinas, Diamante, Dover, Oso Grande, Sweet Charlie, Toyonoka, Tudla e Ventana, nas condições climáticas da região Centro-Sul do Paraná. Foram analisados 29 caracteres morfoagronômicos relacionados com a planta, folha, flor, fruto e aquênios do morangueiro. As similaridades genéticas foram calculadas por meio de análise multivariada e, os cultivares, agrupados com base na matriz de similaridade genética, usando-se UPGMA. Dentre os 29 caracteres morfoagronômicos avaliados, oito apresentaram diferenças não significativas (p < 0,05. A similaridade média foi de 38%, variando de 19 (aromas e camino real a 62% (Camino Real e Camarosa; Aromas e Sweet Charlie. O dendrograma alocou os cultivares em quatro grupos, contudo, essa divisão não foi coerente com a origem e genealogia dos cultivares. O cultivar Tudla apresenta elevado potencial "per se" para utilização em programas de melhoramento. O cruzamento mais promissor com base nos caracteres morfoagronômicos é entre os cultivares Camarosa e Campinas.

  12. Validation of a model to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD: the rotterdam ischemic heart disease and stroke computer simulation (RISC) model.

    Science.gov (United States)

    van Kempen, Bob J H; Ferket, Bart S; Hofman, Albert; Steyerberg, Ewout W; Colkesen, Ersen B; Boekholdt, S Matthijs; Wareham, Nicholas J; Khaw, Kay-Tee; Hunink, M G Myriam

    2012-12-06

    We developed a Monte Carlo Markov model designed to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD. Internal, predictive, and external validity of the model have not yet been established. The Rotterdam Ischemic Heart Disease and Stroke Computer Simulation (RISC) model was developed using data covering 5 years of follow-up from the Rotterdam Study. To prove 1) internal and 2) predictive validity, the incidences of coronary heart disease (CHD), stroke, CVD death, and non-CVD death simulated by the model over a 13-year period were compared with those recorded for 3,478 participants in the Rotterdam Study with at least 13 years of follow-up. 3) External validity was verified using 10 years of follow-up data from the European Prospective Investigation of Cancer (EPIC)-Norfolk study of 25,492 participants, for whom CVD and non-CVD mortality was compared. At year 5, the observed incidences (with simulated incidences in brackets) of CHD, stroke, and CVD and non-CVD mortality for the 3,478 Rotterdam Study participants were 5.30% (4.68%), 3.60% (3.23%), 4.70% (4.80%), and 7.50% (7.96%), respectively. At year 13, these percentages were 10.60% (10.91%), 9.90% (9.13%), 14.20% (15.12%), and 24.30% (23.42%). After recalibrating the model for the EPIC-Norfolk population, the 10-year observed (simulated) incidences of CVD and non-CVD mortality were 3.70% (4.95%) and 6.50% (6.29%). All observed incidences fell well within the 95% credibility intervals of the simulated incidences. We have confirmed the internal, predictive, and external validity of the RISC model. These findings provide a basis for analyzing the effects of modifying cardiovascular disease risk factors on the burden of CVD with the RISC model.

  13. Hard coatings by plasma CVD on polycarbonate for automotive and optical applications

    International Nuclear Information System (INIS)

    Schmauder, T.; Nauenburg, K.-D.; Kruse, K.; Ickes, G.

    2006-01-01

    In many applications, plastic surfaces need coatings as a protection against abrasion or weathering. Leybold Optics is developing Plasma CVD processes and machinery for transparent hard coatings (THC) for polycarbonate parts. In this paper we present the current features and remaining challenges of this technique. The coatings generally show excellent adhesion. Abrasion resistance is superior to commonly used lacquers. Climate durability of the coating has been improved to pass the tests demanded by automotive specifications. Current activities are focused on improving the durability under exposure to UV radiation. Estimations show that our high-rate plasma CVD hard coating process is also economically competitive to lacquering

  14. Anisotropy and dimensional characteristics in CVD route Y1Ba2Cu3O7-δ

    International Nuclear Information System (INIS)

    Watanabe, K.; Kobayashi, N.; Awaji, S.; Yamane, H.; Hirai, T.; Muto, Y.

    1993-01-01

    The anisotropic behaviors of the upper critical field B c2 and the critical current density J c were investigated in Y 1 Ba 2 Cu 3 O 7-δ films prepared by a chemical vapor deposition (CVD) route. The angular dependence of J c at fixed temperature, the field dependence of J c at fixed angle, and the temperature dependence of J c at fixed field were measured. The obtained results were explored in terms of the dimensional superconducting characteristics. The important information on the anisotropic behaviors of J c in CVD-Y 1 Ba 2 Cu 3 O 7-δ was discussed from a viewpoint of the flux pinning. (orig.)

  15. Validation of a model to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD: the rotterdam ischemic heart disease and stroke computer simulation (RISC) model

    NARCIS (Netherlands)

    van Kempen, Bob J. H.; Ferket, Bart S.; Hofman, Albert; Steyerberg, Ewout W.; Colkesen, Ersen B.; Boekholdt, S. Matthijs; Wareham, Nicholas J.; Khaw, Kay-Tee; Hunink, M. G. Myriam

    2012-01-01

    Background: We developed a Monte Carlo Markov model designed to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD. Internal, predictive, and external validity of the model have not yet been established. Methods: The Rotterdam Ischemic Heart Disease

  16. Validation of a model to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD: The rotterdam ischemic heart disease and stroke computer simulation (RISC) model

    NARCIS (Netherlands)

    B.J.H. van Kempen (Bob); B.S. Ferket (Bart); A. Hofman (Albert); E.W. Steyerberg (Ewout); E.B. Colkesen (Ersen); S.M. Boekholdt (Matthijs); N.J. Wareham (Nick); K-T. Khaw (Kay-Tee); M.G.M. Hunink (Myriam)

    2012-01-01

    textabstractBackground: We developed a Monte Carlo Markov model designed to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD. Internal, predictive, and external validity of the model have not yet been established.Methods: The Rotterdam Ischemic

  17. Thermodynamic and experimental studies of the CVD of A-15 superconductors. I

    International Nuclear Information System (INIS)

    Madar, R.; Weiss, F.; Fruchart, R.; Bernard, C.

    1978-01-01

    This paper deals with the experimental and thermodynamic study of the chemical vapor deposition (CVD) synthesis of Nb 3 Ga layers on various metallic and insulating substrates using the coreduction of mixed halides by hydrogen. Thermodynamic equilibrium in the seven-component system Nb-Ga-H-Cl-Si-O-Ar has been calculated using the method of minimization of the system Gibbs free energy as a function of the variables directly available in the CVD system. The chosen variables were the chloride ratio, the reduction and dilution parameters and the temperature of the deposition zone. The equilibrium compositions were calculated for the two composition limits of the A-15 phase: NbGasub(0.15) and Nb 3 Ga. They are presented in the form of CVD phase diagrams. A CVD reactor has been set up and more than one hundred measurements have been made in order to check the validity of the equilibrium calculations. The comparisons between equilibrium and experimental results show a good agreement and lead to a better understanding of the chemistry and thermodynamics of the system. (Auth.)

  18. Control of Reaction Surface in Low Temperature CVD to Enhance Nucleation and Conformal Coverage

    Science.gov (United States)

    Kumar, Navneet

    2009-01-01

    The Holy Grail in CVD community is to find precursors that can afford the following: good nucleation on a desired substrate and conformal deposition in high AR features. Good nucleation is not only necessary for getting ultra-thin films at low thicknesses; it also offers films that are smooth at higher thickness values. On the other hand,…

  19. CVD of SiC and AlN using cyclic organometallic precursors

    Science.gov (United States)

    Interrante, L. V.; Larkin, D. J.; Amato, C.

    1992-01-01

    The use of cyclic organometallic molecules as single-source MOCVD precursors is illustrated by means of examples taken from our recent work on AlN and SiC deposition, with particular focus on SiC. Molecules containing (AlN)3 and (SiC)2 rings as the 'core structure' were employed as the source materials for these studies. The organoaluminum amide, (Me2AlNH2)3, was used as the AlN source and has been studied in a molecular beam sampling apparatus in order to determine the gas phase species present in a hot-wall CVD reactor environment. In the case of SiC CVD, a series of disilacyclobutanes (Si(XX')CH2)2 (with X and X' = H, CH3, and CH2SiH2CH3), were examined in a cold-wall, hot-stage CVD reactor in order to compare their relative reactivities and prospective utility as single-source CVD precursors. The parent compound, disilacyclobutane, (SiH2CH2)2, was found to exhibit the lowest deposition temperature (ca. 670 C) and to yield the highest purity SiC films. This precursor gave a highly textured, polycrystalline film on the Si(100) substrates.

  20. CVD growth and characterization of 3C-SiC thin films

    Indian Academy of Sciences (India)

    Unknown

    Cubic silicon carbide (3C-SiC) thin films were grown on (100) and (111) Si substrates by CVD technique using ... of grown films were studied using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and X-ray ... the oxide mask gets damaged (Edgar et al 1998). There- fore, lower ...

  1. The effect of percentage carbonon the CVD coating of plain carbon ...

    African Journals Online (AJOL)

    Two steels En 3 and En 39 were given a TiC-TiN CVD coating in the carburized and uncarburized conditions. The continuity of the coatings and their adherance to the substrate were examined. The thickness of the deposited coatings were also measured, their adherence to the substrate and their thickness was off ected by ...

  2. Hexagonal Boron Nitride assisted transfer and encapsulation of large area CVD graphene

    Science.gov (United States)

    Shautsova, Viktoryia; Gilbertson, Adam M.; Black, Nicola C. G.; Maier, Stefan A.; Cohen, Lesley F.

    2016-07-01

    We report a CVD hexagonal boron nitride (hBN-) assisted transfer method that enables a polymer-impurity free transfer process and subsequent top encapsulation of large-area CVD-grown graphene. We demonstrate that the CVD hBN layer that is utilized in this transfer technique acts as a buffer layer between the graphene film and supporting polymer layer. We show that the resulting graphene layers possess lower doping concentration, and improved carrier mobilities compared to graphene films produced by conventional transfer methods onto untreated SiO2/Si, SAM-modified and hBN covered SiO2/Si substrates. Moreover, we show that the top hBN layer used in the transfer process acts as an effective top encapsulation resulting in improved stability to ambient exposure. The transfer method is applicable to other CVD-grown 2D materials on copper foils, thereby facilitating the preparation of van der Waals heterostructures with controlled doping.

  3. The integration of epigenetics and genetics in nutrition research for CVD risk factors

    Science.gov (United States)

    There is increasing evidence documenting gene-by-environment (G x E) interactions for CVD related traits. However, the underlying mechanisms are still unclear. DNA methylation may represent one of such potential mechanisms. The objective of this review paper is to summarise the current evidence supp...

  4. CVD of solid oxides in porous substrates for ceramic membrane modification

    NARCIS (Netherlands)

    Lin, Y.S.; Lin, Y.S.; Burggraaf, Anthonie; Burggraaf, A.J.

    1992-01-01

    The deposition of yttria-doped zirconia has been experimented systematically in various types of porous ceramic substrates by a modified chemical vapor deposition (CVD) process operating in an opposing reactant geometry using water vapor and corresponding metal chloride vapors as reactants. The

  5. Large-area selective CVD epitaxial growth of Ge on Si substrates

    NARCIS (Netherlands)

    Sammak, A.; De Boer, W.; Nanver, L.K.

    2011-01-01

    Selective epitaxial growth of crystalline Ge on Si in a standard ASM Epsilon 2000 CVD reactor is investigated for the fabrication of Ge p+n diodes. At the deposition temperature of 700?C, most of the lattice mismatch-defects are trapped within first 300nm of Ge growth and good quality single crystal

  6. Merging Standard CVD Techniques for GaAs and Si Epitaxial Growth

    NARCIS (Netherlands)

    Sammak, A.; De Boer, W.; Van den Bogaard, A.; Nanver, L.K.

    2010-01-01

    A commercial Chemical Vapor Deposition (CVD) system, the ASMI Epsilon 2000 designed for Si and SiGe epitaxy, has, for the first time, been equipped for the growth of GaAs compounds in a manner that does not exclude the use of the system also for Si-based depositions. With the new system, intrinsic,

  7. Ge-on-Si : Single-Crystal Selective Epitaxial Growth in a CVD Reactor

    NARCIS (Netherlands)

    Sammak, A.; De Boer, W.B.; Nanver, L.K.

    2012-01-01

    A standard Si/SiGe ASM CVD reactor that was recently modified for merging GaAs and Si epitaxial growth in one system is utilized to achieve intrinsic and doped epitaxial Ge-on-Si with low threading dislocation and defect densities. For this purpose, the system is equipped with 2% diluted GeH4 as the

  8. Synthesis of crystalline Ge nanoclusters in PE-CVD-deposited SiO2 films

    DEFF Research Database (Denmark)

    Leervad Pedersen, T.P.; Skov Jensen, J.; Chevallier, J.

    2005-01-01

    The synthesis of evenly distributed Ge nanoclusters in plasma-enhanced chemical-vapour-deposited (PE-CVD) SiO2 thin films containing 8 at. % Ge is reported. This is of importance for the application of nanoclusters in semiconductor technology. The average diameter of the Ge nanoclusters can...

  9. Hydrogen termination of CVD diamond films by high-temperature annealing at atmospheric pressure

    NARCIS (Netherlands)

    Seshan, V.; Ullien, D.; Castellanos-Gomez, A.; Sachdeva, S.; Murthy, D.H.K.; Savenije, T.J.; Ahmad, H.A.; Nunney, T.S.; Janssens, S.D.; Haenen, K.; Nesládek, M.; Van der Zant, H.S.J.; Sudhölter, E.J.R.; De Smet, L.C.P.M.

    2013-01-01

    A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ?50 ml/min (STP) at

  10. An economic CVD technique for pure SnO 2 thin films deposition

    Indian Academy of Sciences (India)

    A modified new method of CVD for formation of pure layers of tin oxide films was developed. This method is very simple and inexpensive and produces films with good electrical properties. The effect of substrate temperature on the sheet resistance, resistivity, mobility, carrier concentration and transparency of the films has ...

  11. A beam radiation monitor based on CVD diamonds for SuperB

    Science.gov (United States)

    Cardarelli, R.; Di Ciaccio, A.

    2013-08-01

    Chemical Vapor Deposition (CVD) diamond particle detectors are in use in the CERN experiments at LHC and at particle accelerator laboratories in Europe, USA and Japan mainly as beam monitors. Nowadays it is considered a proven technology with a very fast signal read-out and a very high radiation tolerance suitable for measurements in high radiation environment zones i.e. near the accelerators beam pipes. The specific properties of CVD diamonds make them a prime candidate for measuring single particles as well as high-intensity particle cascades, for timing measurements on the sub-nanosecond scale and for beam protection systems in hostile environments. A single-crystalline CVD (scCVD) diamond sensor, read out with a new generation of fast and high transition frequency SiGe bipolar transistor amplifiers, has been tested for an application as radiation monitor to safeguard the silicon vertex tracker in the SuperB detector from excessive radiation damage, cumulative dose and instantaneous dose rates. Test results with 5.5 MeV alpha particles from a 241Am radioactive source and from electrons from a 90Sr radioactive source are presented in this paper.

  12. Photo-Hall measurements on phosphorus-doped n-type CVD diamond at low temperatures

    Czech Academy of Sciences Publication Activity Database

    Remeš, Zdeněk; Kalish, R.; Uzan-Saguy, C.; Baskin, E.; Nesládek, M.; Koizumi, S.

    2003-01-01

    Roč. 199, č. 1 (2003), s. 82-86 ISSN 0031-8965 EU Projects: European Commission(XE) HPRN-CT-1999-00139 Institutional research plan: CEZ:AV0Z1010914 Keywords : photo-Hall measurements * CVD diamonnd * phosphorus doped Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.950, year: 2003

  13. An economic CVD technique for pure SnO2 thin films deposition ...

    Indian Academy of Sciences (India)

    An economic CVD technique for pure SnO2 thin films deposition: Temperature effects ..... C are depicted in figure 7. It is observed that the cut-off wave- ... cating that the energy gap of the SnO2 films varies among. 3·54, 3·35 and 1·8 eV.

  14. Thermoluminescence properties of undoped diamond films deposited using HF CVD technique

    Directory of Open Access Journals (Sweden)

    Paprocki K.

    2018-03-01

    Full Text Available Natural diamond has been considered as a perspective material for clinical radiation dosimetry due to its tissuebiocompatibility and chemical inertness. However, the use of natural diamond in radiation dosimetry has been halted by the high market price. The recent progress in the development of CVD techniques for diamond synthesis, offering the capability of growing high quality diamond layers, has renewed the interest in using this material in radiation dosimeters having small geometricalsizes. Polycrystalline CVD diamond films have been proposed as detectors and dosimeters of β and α radiation with prospective applications in high-energy photon dosimetry. In this work, we present a study on the TL properties of undoped diamond film samples grown by the hot filament CVD (HF CVD method and exposed to β and α radiation. The glow curves for both types of radiation show similar character and can be decomposed into three components. The dominant TL peaks are centered at around 610 K and exhibit activation energy of the order of 0.90 eV.

  15. Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

    Czech Academy of Sciences Publication Activity Database

    Nesládek, M.; Mareš, Jiří J.; Tromson, D.; Mer, Ch.; Bergonzo, P.; Hubík, Pavel; Krištofik, Jozef

    2006-01-01

    Roč. 7, Suppl. 1 (2006), S41-S44 ISSN 1468-6996 R&D Projects: GA ČR(CZ) GA202/06/0040 Institutional research plan: CEZ:AV0Z10100521 Keywords : superconductivity * electrical transport * doping * CVD diamond Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2006

  16. Thermoluminescence properties of undoped and nitrogen-doped CVD diamond exposed to gamma radiation

    International Nuclear Information System (INIS)

    Barboza-Flores, M.; Gastelum, S.; Cruz-Zaragoza, E.; Melendrez, R.; Chernov, V.; Pedroza-Montero, M.; Favalli, A.

    2008-01-01

    It is known that the thermoluminescence (TL) performance of CVD diamond depends on the impurity concentration and doping materials introduced during growing. We report on the TL properties of undoped and 750 ppm nitrogen-doped CVD diamond grown on (0 0 1) silicon substrate. The samples were exposed to gamma radiation from a Gammacell 200 Nordion irradiator in the 10-500 Gy dose range at 627 mGy/min dose rate. The nitrogen-doped CVD diamond sample exhibited a TL glow curve peaked around 537 K and a small shoulder about 411 K and a linear dose behavior in the 10-60 Gy dose range. In contrast, the undoped specimen showed a 591 K peaked TL glow curve and linear dose response for 10-100 Gy doses. However, both samples displayed a non-linear dose response for doses higher than 100 Gy. The doping effects seem to cause a higher TL efficiency, which may be attributed to the differences in the diamond bonding and amorphous carbon on the CVD samples as well as to the presence of nitrogen. In addition, the nitrogen content may produce some structural and morphological surface effects, which may account for the distinctive TL features and dose response of the diamond samples

  17. Red blood cell rheology in patients with chronic venous disease (CVD)

    NARCIS (Netherlands)

    Chwała, Maciej; Spannbauer, Anna; Teległów, Aneta; Cencora, Andrzej; Marchewka, Anna; Hardeman, Max R.; Dabrowski, Zbigniew

    2009-01-01

    Rheological studies concerning aggregation and elongation of erythrocytes were carried out in 21 patients (mean age 56 years) with chronic venous disease (CVD) and 10 (mean age 45 years) healthy control subjects, with the use of a LORCA device. Higher values of parameters characterizing both

  18. Optimization of CVD parameters for long ZnO NWs grown on ITO

    Indian Academy of Sciences (India)

    The optimization of chemical vapour deposition (CVD) parameters for long and vertically aligned (VA) ZnO nanowires (NWs) were investigated. Typical ZnO NWs as a single crystal grown on indium tin oxide (ITO)-coated glass substrate were successfully synthesized. First, the conducted side of ITO–glass substrate was ...

  19. Computation of flow and thermal fields in a model CVD reactor

    Indian Academy of Sciences (India)

    Mixing of coaxial jets within a tube in the presence of blockage has been numerically studied. This configuration is encountered during the modelling of flow and heat transfer in CVD (chemical vapour deposition) reactors. For the conditions prevailing in the reactor, the Reynolds numbers are low and flow can be taken to be ...

  20. The role of (sub)-surface oxygen on the surface electronic structure of hydrogen terminated (100) CVD diamond

    NARCIS (Netherlands)

    Deferme, W.; Tanasa, G.; Amir, J.; Haenen, K.; Nesladek, M.; Flipse, C.F.J.

    2006-01-01

    In this work, scanning tunnelling microscopy (STM) and scanning tunnelling spectroscopy (STS) were applied to investigate the surface morphol. and the surface electronic structure of plasma-treated (100)-oriented CVD diamond films. These films were hydrogenated using a conventional MWPE-CVD

  1. Cold-walled UHV/CVD batch reactor for the growth of Si1_x/Gex layers

    DEFF Research Database (Denmark)

    Thomsen, Erik Vilain; Christensen, Carsten; Andersen, C.R.

    1997-01-01

    A novel cold-walled, lamp-heated, ultrahigh vacuum chemical vapor deposition (UHV/CVD) batch system for the growth of SiGe layers is presented. This system combines the batch capability of the standard UHV/CVD furnace with the temperature processing available in rapid thermal processing (Rm...

  2. Correlates of CVD and discussing sexual issues with physicians among male military veterans.

    Science.gov (United States)

    Smith, Matthew Lee; Goltz, Heather Honoré; Motlagh, Audry S; Ahn, SangNam; Bergeron, Caroline D; Ory, Marcia G

    2016-10-01

    This study aims to identify socio-demographic and health behavior factors associated with cardiovascular disease (CVD) diagnosis and patient-physician communication concerning sexual issues among older Veterans. Cross-sectional data were collected from 635 male Veterans over age 55 years as part of the 2010 National Social Life, Health and Aging Project, a nationally-representative, population-based study of community-dwelling older Americans. Two independent logistic regression analyses were performed. Over 33% of Veterans were aged 75 years or older. Over one-half of participants reported having a CVD diagnosis (58%) and sexual intercourse within the previous year (58%); over one-third (37%) reported having one or more sexual dysfunctions and discussing sexual issues with their physician (42%). Veterans diagnosed with CVD were significantly more likely to self-identify as racial/ethnic minorities (OR=1.89, P=0.021), have more chronic disease comorbidities (OR=1.23, P=0.041), and have more sexual dysfunctions (OR=1.19, P=0.028). Veterans diagnosed with CVD were significantly less likely to report having sex within the previous year (OR=0.53, P=0.005). Veterans who reported discussing sexual issues with a physician were significantly more likely to be ≥75 years (OR=1.79, P=0.010), and report more than a high school education (OR=1.62, P=0.016), CVD diagnosis (OR=1.59, P=0.015), sex within the previous year (OR=1.69, P=0.033), and trouble achieving/maintaining an erection (OR=3.39, Paging and sexual health/counseling services. These services should promote increased patient-physician communication as well as referrals between physicians and sex health/counseling specialists. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods.

    Science.gov (United States)

    Vilaró, Ignasi; Yagüe, Jose L; Borrós, Salvador

    2017-01-11

    Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O 2 - and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1H,1H,2H,2H-perfluorodecyl acrylate-ethylene glycol diacrylate [p(PFDA-co-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties.

  4. FY1995 development of a clean CVD process by evaluation and control of gas phase nucleation phenomena; 1995 nendo kisokaku seisei gensho no hyoka to seigyo ni yoru clean CVD process no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The purpose of this study is to develop a high-rate and clean chemical vapor deposition (CVD) process as a breakthrough technique to overcome the problems that particles generated in the gas phase during CVD process for preparation of functional thin films cause reduced product yield and deterioration of the films. In the CVD process proposed here, reactant gas and generated particles are electrically charged to control the motion of them with an electric field. In this study, gas-phase nucleation phenomena are evaluated both theoretically and experimentally. A high-rate, ionized CVD method is first developed, in which reactant gas and generated particles are charged with negative ions generated from a radioisotope source and the UV/photoelectron method, and the motion of the charged gas and particles is controlled with an electric field. Charging and transport processes of fine particles are then investigated experimentally and theoretically to develop a clean CVD method in which generated particles are removed with the electric forces. As a result, quantitative evaluation of the charging and transport process was made possible. We also developed devices for measuring the size distribution and concentration of fine particles in low pressure gas such as those found in plasma CVD processes. In addition, numerical simulation and experiments in this study for a TEOS/O{sub 3} CVD process to prepare thin films could determine reaction rates which have not been known so far and give information on selecting good operation conditions for the process. (NEDO)

  5. Polinização de morangueiro por Apis mellifera em ambiente protegido Strawberry polinization through Apis mellifera in protected environment

    Directory of Open Access Journals (Sweden)

    Eunice Oliveira Calvete

    2010-03-01

    Full Text Available Este trabalho objetivou comparar a produtividade e a qualidade dos frutos comerciáveis no morangueiro, em ambiente protegido, utilizando a espécie de abelha Apis mellifera em relação à ausência de um agente polinizador. Foram instalados dois experimentos, utilizando-se das cultivares Camarosa, Oso Grande, Diamante e Aromas (tratamentos, no período de 05 de maio a 19 de dezembro de 2006. No primeiro experimento, não havia polinizadores (testemunha. O segundo foi polinizado pela espécie de abelha Apis mellifera. Os tratamentos (cultivares foram dispostos, em cada experimento, em um delineamento completamente casualizado, com seis repetições. Foram avaliadas características de rendimento, bem como análise físico-química dos frutos de cada cultivar. Quanto ao rendimento, a maior produção obtida foi com a cultivar Camarosa tanto na ausência quanto na presença de polinizadores (907,46 g. planta-1 e 1.054,93 g. planta-1, respectivamente, ao passo que a cultivar Oso Grande apresentou menor número de frutos deformados.This work objectified to compare the productivity and the quality of the strawberry marketable fruits in protected environment, using the species of bee Apis mellifera in relation of the absence of a polinizator agent. It was installed two experiments using the cultivates Camarosa, Oso Grande, Diamante and Aromas (treatments, in the period of May 5 th until December 19th of 2006. The first experiment did not have polinizatores agents (control. The second was polinizated by the species of bee Apis mellifera. The treatments (cultivars had been arranged, in each experiment in a randomized blocks with 6 repetitions. They were evaluated income characteristics, as well as analysis physicist-chemistry of the fruits of each cultivar. For the income, the biggest production was gotten in cultivar Camarosa, for the first and the second experiment (907,46 g. plant-1 and 1054,93 g. plant-1, respectively, in the way that the cultivate

  6. Desempenho de cultivares de morango submetidas a diferentes tipos de polinização em cultivo protegido

    Directory of Open Access Journals (Sweden)

    Sidia Witter

    2012-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de diferentes tipos de polinização sobre a qualidade de frutos de cultivares de morangueiro e sua contribuição isolada para a massa dos frutos, bem como determinar o potencial de Plebeia nigriceps (Hymenoptera: Apidae, Meliponini como agente polinizador em ambiente protegido. As cultivares Aromas, Diamante e Cegnidarem foram submetidas a tratamentos com autopolinização, polinização por P. nigriceps e polinização livre. Os experimentos foram conduzidos em estufa tipo pampeana, coberta com polietileno transparente e desprovida de telas anti-insetos nas laterais, com 1.344 plantas. Para as avaliações, foram marcadas 56 flores primárias em botão, de cada cultivar, e considerou-se cada planta uma repetição. Avaliaram-se massa de matéria fresca, peso, diâmetro, comprimento e presença de deformação nos frutos. A polinização entomófila tem contribuição variada à massa dos frutos, de acordo com a cultivar. As cultivares apresentam sensibilidade variada à autopolinização, no que se refere à incidência de frutos deformados. A interferência da polinização entomófila na produtividade do morangueiro está mais relacionada à redução do percentual de frutos deformados do que ao aumento da massa dos frutos em si. O comportamento de P. nigriceps indica que a espécie apresenta potencial para polinização da cultura do morangueiro em ambiente protegido.

  7. Hard Coat Layers by PE-CVD Process for the Top Surface of Touch Panel

    International Nuclear Information System (INIS)

    Okunishi, T; Sato, N; Yazawa, K

    2013-01-01

    In order to protect surface from damages, the high pencil hardness and the high abrasion resistance are required for the hard coat layers on polyethylene telephthalate (PET) films for the application of touch panel surface. We have already found that the UV-curing-hard-coat-polymer (UHP) coated PET films show the poor abrasion resistance, while they have the high pencil hardness. It reveals that the abrasion resistance of hard coat layers of the UHP is not simply dependent on the pencil hardness. In this work, we have studied to improve the abrasion resistance of SiOC films as hard coat layers, which were formed by PE-CVD process on UHP coated PET. The abrasion resistance was evaluated by Taber abrasion test. PE-CVD hard coat layers which formed on UHP coater PET films have showed the better abrasion resistance and have the possibility of substitution to the thin glass sheets for touch panel application.

  8. Comparative study of dlc coatings by pvd against cvd technique on textile dents

    International Nuclear Information System (INIS)

    Malik, M.; Alam, S.; Iftikhar, F.

    2007-01-01

    Diamond like Carbon (DLC) film is a hard amorphous carbon hydride film formed by Physical or Chemical vapor deposition (PVD or CVD) techniques. Due to its unique properties especially high hardness, lower coefficient of friction and lubricious nature, these coatings are not only used to extend the life of cutting tools but also for non cutting applications such as for forming dies, molds and on many functional parts of textile. In the present work two techniques were employed i.e. PVD and CVD for deposition of diamond like carbon film on textile dents. These dents are used as thread guider in high speed weaving machine. The measurement of coating thickness, adhesion, hardness and roughness values indicates that overall properties of DLC coating developed by PVD LARC technology reduces abrasion and increases the workability and durability of textile dents as well as suppress the need of lubricants. (author)

  9. Thermodynamic study of CVD-ZrO{sub 2} phase diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Huerta, A.M., E-mail: atorresh@ipn.m [Research Center for Applied Science and Advanced Technology, Altamira-IPN, Altamira C.P.89600 Tamaulipas (Mexico); Vargas-Garcia, J.R. [Dept of Metallurgical Eng., ESIQIE-IPN, Mexico 07300 D.F. (Mexico); Dominguez-Crespo, M.A. [Research Center for Applied Science and Advanced Technology, Altamira-IPN, Altamira C.P.89600 Tamaulipas (Mexico); Romero-Serrano, J.A. [Dept of Metallurgical Eng., ESIQIE-IPN, Mexico 07300 D.F. (Mexico)

    2009-08-26

    Chemical vapor deposition (CVD) of zirconium oxide (ZrO{sub 2}) from zirconium acetylacetonate Zr(acac){sub 4} has been thermodynamically investigated using the Gibbs' free energy minimization method and the FACTSAGE program. Thermodynamic data Cp{sup o}, DELTAH{sup o} and S{sup o} for Zr(acac){sub 4} have been estimated using the Meghreblian-Crawford-Parr and Benson methods because they are not available in the literature. The effect of deposition parameters, such as temperature and pressure, on the extension of the region where pure ZrO{sub 2} can be deposited was analyzed. The results are presented as calculated CVD stability diagrams. The phase diagrams showed two zones, one of them corresponds to pure monoclinic phase of ZrO{sub 2} and the other one corresponds to a mix of monoclinic phase of ZrO{sub 2} and graphite carbon.

  10. Pulse-height defect in single-crystal CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Beliuskina, O.; Imai, N. [The University of Tokyo, Center for Nuclear Study, Wako, Saitama (Japan); Strekalovsky, A.O.; Aleksandrov, A.A.; Aleksandrova, I.A.; Ilich, S.; Kamanin, D.V.; Knyazheva, G.N.; Kuznetsova, E.A.; Mishinsky, G.V.; Pyatkov, Yu.V.; Strekalovsky, O.V.; Zhuchko, V.E. [JINR, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow Region (Russian Federation); Devaraja, H.M. [Manipal University, Manipal Centre for Natural Sciences, Manipal, Karnataka (India); Heinz, C. [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); Heinz, S. [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Hofmann, S.; Kis, M.; Kozhuharov, C.; Maurer, J.; Traeger, M. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Pomorski, M. [CEA, LIST, Diamond Sensor Laboratory, CEA/Saclay, Gif-sur-Yvette (France)

    2017-02-15

    The pulse-height versus deposited energy response of a single-crystal chemical vapor deposition (scCVD) diamond detector was measured for ions of Ti, Cu, Nb, Ag, Xe, Au, and of fission fragments of {sup 252} Cf at different energies. For the fission fragments, data were also measured at different electric field strengths of the detector. Heavy ions have a significant pulse-height defect in CVD diamond material, which increases with increasing energy of the ions. It also depends on the electrical field strength applied at the detector. The measured pulse-height defects were explained in the framework of recombination models. Calibration methods known from silicon detectors were modified and applied. A comparison with data for the pulse-height defect in silicon detectors was performed. (orig.)

  11. Diameter Tuning of Single-Walled Carbon Nanotubes by Diffusion Plasma CVD

    Directory of Open Access Journals (Sweden)

    Toshiaki Kato

    2011-01-01

    Full Text Available We have realized a diameter tuning of single-walled carbon nanotubes (SWNTs by adjusting process gas pressures with plasma chemical vapor deposition (CVD. Detailed photoluminescence measurements reveal that the diameter distribution of SWNTs clearly shifts to a large-diameter region with an increase in the pressure during plasma CVD, which is also confirmed by Raman scattering spectroscopy. Based on the systematical investigation, it is found that the main diameter of SWNTs is determined by the pressure during the heating in an atmosphere of hydrogen and the diameter distribution is narrowed by adjusting the pressure during the plasma generation. Our results could contribute to an application of SWNTs to high-performance thin-film transistors, which requires the diameter-controlled semiconductor-rich SWNTs.

  12. The effect of alkaline doped catalysts on the CVD synthesis of carbon nanotubes

    DEFF Research Database (Denmark)

    Nemeth, Krisztian; Nemeth, Zoltan; Fejes, Dora

    2011-01-01

    The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount o...... of the dopant alkali compounds varied from 1 to 5%. As prepared CNTs were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD) and Raman microscopy. Results revealed that both carbon yield and deposit could be increased over doped catalysts.......The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount...

  13. Board diversity and corporate voluntary disclosure (CVD in the annual reports of Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Abdur Rouf

    2016-10-01

    Full Text Available This is an exploratory study designed to investigate the extant and nature of corporate voluntary disclosure (CVD in corporate annual reports of Bangladesh. Specifically, examine the relationship between board diversity and corporate voluntary disclosures. The paper is based on a sample of 106 listed non-financial companies in Dhaka Stock Exchanges (DSE from the period 2007-2011 and all the companies are selected by Judgment Sampling. The study is used ordinary least squares regression model to examine the relationship between explanatory variables and voluntary disclosure. Using an unweighted relative disclosure index for measuring voluntary disclosure, the empirical results indicate that Percentage Female Director (PFD, Board Leadership Structure (BLS and Total Assets (TA are positively association with corporate voluntary disclosure (CVD. In contrast, the extent of corporate voluntary disclosure is negatively associated with a Percentage of equity owned by the insiders to all equity of the firm higher management ownership

  14. Plasma CVD reactor with two-microwave oscillators for diamond film synthesis

    International Nuclear Information System (INIS)

    Nagatsu, M.; Miyake, M.; Maeda, J.

    2006-01-01

    In this study, we present the experimental results of a new type of microwave plasma CVD system, where two of 1.5 kW microwave sources were used for enlarging the plasma discharge and the diamond film growth. One of the microwave oscillators was used to produce the microwave plasma as in the conventional microwave plasma CVD device, while the second one was used to enlarge the plasma by introducing microwave from the launcher mounted at the substrate stage. We demonstrated the enlargement of plasma discharge area from 60 mm to 100 mm in diameter by using the two-microwave oscillators system. Characteristics of diamond films deposited using H 2 /CH 4 plasmas were also investigated using a scanning electron microscope (SEM) and Raman spectroscopy

  15. Temperature dependence of stress in CVD diamond films studied by Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Dychalska Anna

    2015-09-01

    Full Text Available Evolution of residual stress and its components with increasing temperature in chemical vapor deposited (CVD diamond films has a crucial impact on their high temperature applications. In this work we investigated temperature dependence of stress in CVD diamond film deposited on Si(100 substrate in the temperature range of 30 °C to 480 °C by Raman mapping measurement. Raman shift of the characteristic diamond band peaked at 1332 cm-1 was studied to evaluate the residual stress distribution at the diamond surface. A new approach was applied to calculate thermal stress evolution with increasing tempera­ture by using two commonly known equations. Comparison of the residts obtained from the two methods was presented. The intrinsic stress component was calculated from the difference between average values of residual and thermal stress and then its temperature dependence was discussed.

  16. Natural and CVD type diamond detectors as dosimeters in hadrontherapy applications

    International Nuclear Information System (INIS)

    Cirrone, G.A.P.; Cuttone, G.; Rafaele, L.; Sabini, M.G.; De Angelis, C.; Onori, S.; Pacilio, M.; Bucciolini, M.; Bruzzi, M.; Sciortino, S.

    2003-01-01

    Diamond is potentially a suitable material for use as radiation dosimeter; the wide band gap results in low dark currents and low sensitivity to visible light, the high carrier mobility can give rapid response, the very high density of strong bonds in the crystal structure make diamond very resistant to radiation damage; moreover it is tissue equivalent. The more recent advances in the synthesis of polycrystalline diamond by chemical vapour deposition (CVD) techniques have allowed the synthesis of material with electronic properties suitable for dosimetric application. In this paper we will report the results obtained in the study of the response of a natural diamond dosimeter and a CVD one irradiated with 62 AMeV proton beams to demonstrate their possible application in protontherapy

  17. Effect of growth temperature and precursor concentration on synthesis of CVD-graphene from camphor

    Science.gov (United States)

    Rajaram, Narasimman; Patel, Biren; Ray, Abhijit; Mukhopadhyay, Indrajit

    2018-05-01

    Here, we have synthesized CVD-graphene from camphor by using atmospheric pressure (AP)-CVD system on Cu foil. We have studied the effect of growth temperature and camphor concentration by using scanning electron microscopy (SEM) and Raman spectroscopy. The domain size of the graphene is increasing with an increase in the temperature and camphor quantity. The complete coverage of graphene on the Cu foil achieved at 1020 °C. Higher camphor quantity leads to growth of multilayer graphene. The graphene is transferred by PMMA-assisted method onto the glass substrate. The sheet resistance and transmittance of the graphene are 1.5 kohm/sq and 92.7%, respectively.

  18. Development of Health Parameter Model for Risk Prediction of CVD Using SVM

    Directory of Open Access Journals (Sweden)

    P. Unnikrishnan

    2016-01-01

    Full Text Available Current methods of cardiovascular risk assessment are performed using health factors which are often based on the Framingham study. However, these methods have significant limitations due to their poor sensitivity and specificity. We have compared the parameters from the Framingham equation with linear regression analysis to establish the effect of training of the model for the local database. Support vector machine was used to determine the effectiveness of machine learning approach with the Framingham health parameters for risk assessment of cardiovascular disease (CVD. The result shows that while linear model trained using local database was an improvement on Framingham model, SVM based risk assessment model had high sensitivity and specificity of prediction of CVD. This indicates that using the health parameters identified using Framingham study, machine learning approach overcomes the low sensitivity and specificity of Framingham model.

  19. Fish consumption and its motives in households with versus without self-reported medical history of CVD

    DEFF Research Database (Denmark)

    Pieniak, Zuzanna; Verbeke, Wim; Perez-Cueto, Federico

    2008-01-01

    subjective and objective knowledge related to nutrition issues about fish. In the other countries, objective knowledge about fish was on a low level, similar for CVD+ as for CVD- subjects, despite a higher claimed use of medical information sources about fish among CVD+ subjects. Conclusions - Although...... consumption. This study exemplifies the need for nutrition education and more effective communication about fish, not only to the people facing chronic diseases, but also to the broader public. European consumers are convinced that eating fish is healthy, but particular emphasis should be made...

  20. Development of Fe-AI CVD coatings as tritium permeation barrier

    International Nuclear Information System (INIS)

    Chabrol, C.; Schuster, F.; Le Marois, G.; Serra, E.

    1998-01-01

    A specific method of pack-cementation has been developed in order to perform a CVD deposition of Fe-Al alloys on a martensitic steel at a temperature which respects its mechanical properties ( 2 Al 5 intermetallic phases thanks to a low pressure deposition and using a special cement containing Fe and Al. These coatings coated with an Al 2 O 3 top layer drastically reduce the permeation rate of deuterium with regards to the uncoated substrate. (authors)

  1. Growth and characterization of nanodiamond layers prepared using plasma enhanced linear antennas microwave CVD system

    Czech Academy of Sciences Publication Activity Database

    Fendrych, František; Taylor, Andrew; Peksa, Ladislav; Kratochvílová, Irena; Vlček, J.; Řezáčová, V.; Petrák, V.; Kluiber, Z.; Fekete, Ladislav; Liehr, M.; Nesládek, M.

    2010-01-01

    Roč. 43, č. 37 (2010), 374018/1-374018/6 ISSN 0022-3727 R&D Projects: GA AV ČR KAN200100801; GA AV ČR KAN300100801; GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100520 Keywords : nanodiamond, * thin films * PE MW CVD * linear antennas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.105, year: 2010

  2. Mediators and Moderators of Dementia Caregiver Depression and CVD Risk Outcomes in the Pleasant Events Program

    OpenAIRE

    Ho, Jennefer S.

    2016-01-01

    Rationale: Alzheimer’s disease caregivers demonstrate significant elevations in depression compared with noncaregivers. Addressing caregiver depression is of high public health importance due to its ties with overall wellbeing, increased risk for cardiovascular diseases (CVD), and ability to sustain caregiving duties. Improving caregiver mental and physical health may not only decrease healthcare costs, but it may also delay institutionalization of Alzheimer’s disease patients. Despite existi...

  3. A 3D tomographic EBSD analysis of a CVD diamond thin film

    International Nuclear Information System (INIS)

    Liu Tao; Raabe, Dierk; Zaefferer, Stefan

    2008-01-01

    We have studied the nucleation and growth processes in a chemical vapor deposition (CVD) diamond film using a tomographic electron backscattering diffraction method (3D EBSD). The approach is based on the combination of a focused ion beam (FIB) unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

  4. A 3D tomographic EBSD analysis of a CVD diamond thin film

    Directory of Open Access Journals (Sweden)

    Tao Liu, Dierk Raabe and Stefan Zaefferer

    2008-01-01

    Full Text Available We have studied the nucleation and growth processes in a chemical vapor deposition (CVD diamond film using a tomographic electron backscattering diffraction method (3D EBSD. The approach is based on the combination of a focused ion beam (FIB unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

  5. Cold Vacuum Dryer (CVD) Facility Security System Design Description. System 54

    International Nuclear Information System (INIS)

    WHITEHURST, R.

    2000-01-01

    This system design description (SDD) addresses the Cold Vacuum Drying (CVD) Facility security system. The system's primary purpose is to provide reasonable assurance that breaches of security boundaries are detected and assessment information is provided to protective force personnel. In addition, the system is utilized by Operations to support reduced personnel radiation goals and to provide reasonable assurance that only authorized personnel are allowed to enter designated security areas

  6. The Role of Built Environments in Physical Activity, Obesity, and CVD

    OpenAIRE

    Sallis, James F.; Floyd, Myron F.; Rodríguez, Daniel A.; Saelens, Brian E.

    2012-01-01

    In industrialized nations like the United States and Sweden, the vast majority of adults do not meet the physical activity guidelines of 150 minutes per week.1 Inactive lifestyles put most adults at risk of cardiovascular diseases (CVD), diabetes, obesity, some cancers, osteoporosis, and psychological disorders.2 Physical activity can be effective at all phases of chronic disease management, from primordial prevention (prevention of risk factors) through treatment and rehabilitation.2 There i...

  7. Growth of carbon allotropes and plasma characterization in linear antenna microwave plasma CVD system

    Czech Academy of Sciences Publication Activity Database

    Potocký, Štěpán; Babchenko, Oleg; Davydova, Marina; Ižák, Tibor; Čada, Martin; Kromka, Alexander

    2014-01-01

    Roč. 53, č. 5 (2014), "05FP04-1"-"05FP04-3" ISSN 0021-4922 R&D Projects: GA TA ČR TA01011740; GA ČR GAP205/12/0908 Grant - others:AVČR(CZ) M100100902 Institutional support: RVO:68378271 Keywords : antenna linear * CVD system * plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.127, year: 2014

  8. Preparación de tamices moleculares de carbono por CVD

    OpenAIRE

    Manso, R.; Pajares, J. A.; Albiniak, A.; Broniek, E.; Siemieniewska, T.

    2001-01-01

    Carbon molecular sieves (CMS) have been prepared by chemical vapour deposition (CVD) of carbon from the pyrolysis of benzene molecules on activated carbon surfaces. The pyrolysis of benzene at temperatures in the range 650-850 ºC restricts the accessibility of the micropores due to the creation of constrictions on the microporous network. Temperatures higher than 850 ºC (temperature of carbonisation) add difficulties due to decomposition and sinterization processes. Low flows of nitrogen (30 ...

  9. Nanocrystalline sp{sup 2} and sp{sup 3} carbons: CVD synthesis and applications

    Energy Technology Data Exchange (ETDEWEB)

    Terranova, M. L. [Università degli Studi di Roma “Tor Vergata,” via Della Ricerca Scientifica, Dipartimento di Scienze e Tecnologie Chimiche—MinimaLab (Italy); Rossi, M. [Università degli Studi di Roma “Sapienza,” via A. Scarpa, Dipartimento di Scienze di Base e Applicate per l’Ingegneria and Centro di Ricerca per le Nanotecnologie Applicate all’Ingegneria (CNIS) (Italy); Tamburri, E., E-mail: emanuela.tamburri@uniroma2.it [Università degli Studi di Roma “Tor Vergata,” via Della Ricerca Scientifica, Dipartimento di Scienze e Tecnologie Chimiche—MinimaLab (Italy)

    2016-11-15

    The design and production of innovative materials based on nanocrystalline sp{sup 2}- and sp{sup 3}-coordinated carbons is presently a focus of the scientific community. We present a review of the nanostructures obtained in our labs using a series of synthetic routes, which make use of chemical vapor deposition (CVD) techniques for the selective production of non-planar graphitic nanostructures, nanocrystalline diamonds, and hybrid two-phase nanostructures.

  10. CVD Diamond Detectors for Current Mode Neutron Time-of-Flight Spectroscopy at OMEGA/NIF

    International Nuclear Information System (INIS)

    G. J. Schmid; V. Yu. Glebov; A. V. Friensehner; D. R. Hargrove; S. P. Hatchett; N. Izumi; R. A. Lerche; T. W. Phillips; T. C. Sangster; C. Silbernagel; C. Stoecki

    2001-01-01

    We have performed pulsed neutron and pulsed laser tests of a CVD diamond detector manufactured from DIAFILM, a commercial grade of CVD diamond. The laser tests were performed at the short pulse UV laser at Bechtel Nevada in Livermore, CA. The pulsed neutrons were provided by DT capsule implosions at the OMEGA laser fusion facility in Rochester, NY. From these tests, we have determined the impulse response to be 250 ps fwhm for an applied E-field of 500 V/mm. Additionally, we have determined the sensitivity to be 2.4 mA/W at 500 V/mm and 4.0 mA/W at 1000 V/mm. These values are approximately 2 to 5x times higher than those reported for natural Type IIa diamond at similar E-field and thickness (1mm). These characteristics allow us to conceive of a neutron time-of-flight current mode spectrometer based on CVD diamond. Such an instrument would sit inside the laser fusion target chamber close to target chamber center (TCC), and would record neutron spectra fast enough such that backscattered neutrons and x-rays from the target chamber wall would not be a concern. The acquired neutron spectra could then be used to extract DD fuel areal density from the downscattered secondary to secondary ratio

  11. Topographic and spectroscopic characterization of electronic edge states in CVD grown graphene nanoribbons.

    Science.gov (United States)

    Pan, Minghu; Girão, E Costa; Jia, Xiaoting; Bhaviripudi, Sreekar; Li, Qing; Kong, Jing; Meunier, V; Dresselhaus, Mildred S

    2012-04-11

    We used scanning tunneling microscopy and spectroscopy (STM/S) techniques to analyze the relationships between the edge shapes and the electronic structures in as-grown chemical vapor deposition (CVD) graphene nanoribbons (GNRs). A rich variety of single-layered graphene nanoribbons exhibiting a width of several to 100 nm and up to 1 μm long were studied. High-resolution STM images highlight highly crystalline nanoribbon structures with well-defined and clean edges. Theoretical calculations indicate clear spin-split edge states induced by electron-electron Coulomb repulsion. The edge defects can significantly modify these edge states, and different edge structures for both sides of a single ribbon produce asymmetric electronic edge states, which reflect the more realistic features of CVD grown GNRs. Three structural models are proposed and analyzed to explain the observations. By comparing the models with an atomic resolution image at the edge, a pristine (2,1) structure was ruled out in favor of a reconstructed edge structure composed of 5-7 member rings, showing a better match with experimental results, and thereby suggesting the possibility of a defective morphology at the edge of CVD grown nanoribbons. © 2012 American Chemical Society

  12. Freedom poverty: a new tool to identify the multiple disadvantages affecting those with CVD.

    Science.gov (United States)

    Callander, Emily J; Schofield, Deborah J; Shrestha, Rupendra N

    2013-06-20

    It is recognised that CVD affects an individual's financial situation, placing them in income poverty. However, recent developments in poverty measurement practice recognises other forms of disadvantage other than low income, such as poor health and insufficient education also affect living standards. Using the Freedom Poverty Measure, the multiple forms of disadvantage experienced by those with no health condition, heart disease, other diseases of the circulatory system, and all other health conditions was assessed using data on the adult Australian population contained in the 2003 Survey of Disability, Ageing and Carers. 24% of those with heart disease and 23% of those with other diseases of the circulatory system were in freedom poverty, suffering from multiple forms of disadvantage. Those with heart disease and those with other diseases of the circulatory system were around three times more likely to be in freedom poverty (OR 3.02, 95% CI: 2.29-3.99, p<.0001; OR 2.78, 95% CI: 1.94-3.98, p<.0001) than those with no health condition. Recognising the multiple forms of disadvantage suffered by those with CVD provides a clearer picture of their living standards than just looking at their income alone and the high proportion of individuals with CVD that are suffering from multiple forms of disadvantage should make them a target for policy makers wishing to improve living standards. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. Which population groups are most unaware of CVD risks associated with sitting time?

    Science.gov (United States)

    Duncan, Mitch J; Gilson, Nicholas; Vandelanotte, Corneel

    2014-08-01

    Prolonged sitting is an emerging risk factor for poor health yet few studies have examined awareness of the risks associated with sitting behaviours. This study identifies the population subgroups with the highest levels of unawareness regarding the cardiovascular disease (CVD) risks associated with sitting behaviours. Adults (n=1256) living in Queensland, Australia completed a telephone-based survey in 2011, analysis conducted in 2013. The survey assessed participant's socio-demographic characteristics, physical activity, sitting behaviours and awareness of CVD risks associated with three sitting behaviours: 1) sitting for prolonged periods, 2), sitting for prolonged periods whilst also engaging in regular physical activity, and 3) breaking up periods of prolonged sitting with short activity breaks. Population sub-groups with the highest levels of unawareness were identified based on socio-demographic and behavioural characteristics using signal detection analysis. Unawareness ranged from 23.3% to 67.0%. Age was the most important variable in differentiating awareness levels; younger adults had higher levels of unawareness. Body mass index, physical activity, TV viewing, employment status and time spent at work also identified population sub-groups. Unawareness of CVD risk for prolonged sitting was moderately high overall. Younger adults had high levels of unawareness on all of the outcomes examined. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Mechanics-driven patterning of CVD graphene for roll-based manufacturing process

    Science.gov (United States)

    Kim, Sang-Min; Jang, Bongkyun; Jo, Kyungmin; Kim, Donghyuk; Lee, Jihye; Kim, Kyung-Shik; Lee, Seung-Mo; Lee, Hak-Joo; Han, Seung Min; Kim, Jae-Hyun

    2017-06-01

    Graphene is considered as a promising material for flexible and transparent electrodes due to its outstanding electrical, optical, and mechanical properties. Efforts to mass-produce graphene electrodes led to the development of roll-to-roll chemical vapor deposition (CVD) graphene growth and transfer, and the only remaining obstacle to the mass-production of CVD graphene electrodes is a cost-effective patterning technique that is compatible with the roll-to-roll manufacturing. Herein, we propose a mechanics-driven technique for patterning graphene synthesized on copper foil (commonly used in roll-to-roll manufacturing). The copper foil is exposed to high temperature for a prolonged period during the CVD growth of graphene, and thus can result in recrystallization and grain growth of the copper foil and thereby reducing to the yield strength. This softening behavior of the copper was carefully controlled to allow simple stamp patterning of the graphene. The strength of the underlying substrate was controlled for the accuracy of the residual patterns. The proposed stamp patterning technique is mask-less and photoresist-free, and can be performed at room temperature without high-energy sources such as lasers or plasma. To demonstrate the capability of this process to produce a continuous electrode, a transparent in-plane supercapacitor was fabricated using the proposed patterning technique.

  15. Direct CVD Graphene Growth on Semiconductors and Dielectrics for Transfer-Free Device Fabrication.

    Science.gov (United States)

    Wang, Huaping; Yu, Gui

    2016-07-01

    Graphene is the most broadly discussed and studied two-dimensional material because of its preeminent physical, mechanical, optical, and thermal properties. Until now, metal-catalyzed chemical vapor deposition (CVD) has been widely employed for the scalable production of high-quality graphene. However, in order to incorporate the graphene into electronic devices, a transfer process from metal substrates to targeted substrates is inevitable. This process usually results in contamination, wrinkling, and breakage of graphene samples - undesirable in graphene-based technology and not compatible with industrial production. Therefore, direct graphene growth on desired semiconductor and dielectric substrates is considered as an effective alternative. Over the past years, there have been intensive investigations to realize direct graphene growth using CVD methods without the catalytic role of metals. Owing to the low catalytic activity of non-metal substrates for carbon precursor decomposition and graphene growth, several strategies have been designed to facilitate and engineer graphene fabrication on semiconductors and insulators. Here, those developed strategies for direct CVD graphene growth on semiconductors and dielectrics for transfer-free fabrication of electronic devices are reviewed. By employing these methods, various graphene-related structures can be directly prepared on desired substrates and exhibit excellent performance, providing versatile routes for varied graphene-based materials fabrication. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Crystalline silicon thin film growth by ECR plasma CVD for solar cells

    International Nuclear Information System (INIS)

    Licai Wang

    1999-07-01

    This thesis describes the background, motivation and work carried out towards this PhD programme entitled 'Crystalline Silicon Thin Film Growth by ECR Plasma CVD for Solar Cells'. The fundamental principles of silicon solar cells are introduced with a review of silicon thin film and bulk solar cells. The development and prospects for thin film silicon solar cells are described. Some results of a modelling study on thin film single crystalline solar cells are given which has been carried out using a commercially available solar cell simulation package (PC-1D). This is followed by a description of thin film deposition techniques. These include Chemical Vapour Deposition (CVD) and Plasma-Assisted CVD (PACVD). The basic theory and technology of the emerging technique of Electron Cyclotron Resonance (ECR) PACVD, which was used in this research, are introduced and the potential advantages summarised. Some of the basic methods of material and cell characterisation are briefly described, together with the work carried out in this research. The growth by ECR PACVD at temperatures 2 illumination. The best efficiency in the ECR grown structures was 13.76% using an epitaxial emitter. Cell performance was analysed in detail and the factors controlling performance identified by fitting self-consistently the fight and dark current-voltage and spectral response data using PC-1D. Finally, the conclusions for this research and suggestions for further work are outlined. (author)

  17. Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

    Science.gov (United States)

    Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Manfredi, P. F.; Marshall, R. D.; Mishina, M.; Le Normand, F.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

    1999-04-01

    CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/ c and 500 Mev protons up to a fluence of 5×10 15 p/cm 2. We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1×10 15 p/cm 2 and decreases by ≈40% at 5×10 15 p/cm 2. Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/ c and 500 MeV protons up to at least 1×10 15p/cm 2 without signal loss.

  18. Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Meier, D. E-mail: dirk.meier@cern.ch.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Manfredi, P.F.; Marshall, R.D.; Mishina, M.; Le Normand, F.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M

    1999-04-21

    CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/c and 500 Mev protons up to a fluence of 5x10{sup 15} p/cm{sup 2}. We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1x10{sup 15} p/cm{sup 2} and decreases by {approx}40% at 5x10{sup 15} p/cm{sup 2}. Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/c and 500 MeV protons up to at least 1x10{sup 15}p/cm{sup 2} without signal loss.

  19. Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

    International Nuclear Information System (INIS)

    Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Manfredi, P.F.; Marshall, R.D.; Mishina, M.; Le Normand, F.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.

    1999-01-01

    CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/c and 500 Mev protons up to a fluence of 5x10 15 p/cm 2 . We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1x10 15 p/cm 2 and decreases by ∼40% at 5x10 15 p/cm 2 . Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/c and 500 MeV protons up to at least 1x10 15 p/cm 2 without signal loss

  20. Proton Irradiation of CVD Diamond Detectors for High Luminosity Experiments at the LHC

    CERN Document Server

    Meier, D; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jany, C; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Marshall, R D; Mishina, M; Le Normand, F; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

    1999-01-01

    CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/$c$ and 500~MeV protons up to a fluence of $5\\times 10^{15}~p/{\\rm cm^2}$. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to $1\\ times 10^{15}~p/{\\rm cm^2}$ and decreases by $\\approx$40~\\% at $5\\times 10^{15}~p/{\\rm cm^2}$. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radia...

  1. Convection and chemistry effects in CVD: A 3-D analysis for silicon deposition

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.; Tsui, P.; Chait, A.

    1989-01-01

    The computational fluid dynamics code FLUENT has been adopted to simulate the entire rectangular-channel-like (3-D) geometry of an experimental CVD reactor designed for Si deposition. The code incorporated the effects of both homogeneous (gas phase) and heterogeneous (surface) chemistry with finite reaction rates of important species existing in silane dissociation. The experiments were designed to elucidate the effects of gravitationally-induced buoyancy-driven convection flows on the quality of the grown Si films. This goal is accomplished by contrasting the results obtained from a carrier gas mixture of H2/Ar with the ones obtained from the same molar mixture ratio of H2/He, without any accompanying change in the chemistry. Computationally, these cases are simulated in the terrestrial gravitational field and in the absence of gravity. The numerical results compare favorably with experiments. Powerful computational tools provide invaluable insights into the complex physicochemical phenomena taking place in CVD reactors. Such information is essential for the improved design and optimization of future CVD reactors.

  2. Increased risk of cardiovascular disease (CVD) with age in HIV-positive men

    DEFF Research Database (Denmark)

    Petoumenos, K; Reiss, P; Ryom, L

    2014-01-01

    equations. METHODS: We analysed three endpoints: myocardial infarction (MI), coronary heart disease (CHD: MI or invasive coronary procedure) and CVD (CHD or stroke). We fitted a number of parametric age effects, adjusting for known risk factors and antiretroviral therapy (ART) use. The best-fitting age...... rates per 1000 person-years increased from 2.29, 3.11 and 3.65 in those aged 40-45 years to 6.53, 11.91 and 15.89 in those aged 60-65 years, respectively. The best-fitting models included inverse age for MI and age + age(2) for CHD and CVD. In D:A:D there was a slowly accelerating increased risk of CHD...... and CVD per year older, which appeared to be only modest yet was consistently raised compared with the risk in the general population. The relative risk of MI with age was not different between D:A:D and the general population. CONCLUSIONS: We found only limited evidence of accelerating increased risk...

  3. CVD of alternated microcrystalline (MCD) and nanocrystalline (NCD) diamond films on WC-TIC-CO substrates

    International Nuclear Information System (INIS)

    Campos, Raonei Alves; Contin, Andre; Trava-Airoldi, Vladimir J.; Corat, Evaldo Jose; Barquete, Danilo Maciel

    2010-01-01

    CVD Diamond coating of WC-TiC-Co cutting tools has been an alternative to increase tool lifetime. Experiments have shown that residual stresses produced during films growth on WC-TiC-Co substrates significantly increases with increasing film thickness up to 20 μm and usually leads to film delamination. In this work alternated micro- and nanocrystalline CVD diamond films have been used to relax interface stresses and to increase diamond coatings performance. WC-TiC-Co substrates have been submitted to a boronizing thermal diffusion treatment prior to CVD diamond films growth. After reactive heat treatment samples were submitted to chemical etching in acid and alkaline solution. The diamond films deposition was performed using HFCVD reactor with different gas concentrations for microcrystalline (MCD) and nano-crystalline (NCD) films growth. As a result, we present the improvement of diamond films adherence on WC-TiC-Co, evaluated by indentation and machining tests. Samples were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) for qualitative analysis of diamond films. X-ray Diffraction (XRD) was used for phases identification after boronizing process. Diamond film compressive residual stresses were analyzed by Raman Scattering Spectroscopy (RSS). (author)

  4. A CVD Diamond Detector for (n,a) Cross-Section Measurements

    CERN Document Server

    Weiss, Christina; Griesmayer, Erich; Guerrero, Carlos

    A novel detector based on the chemical vapor deposition (CVD) diamond technology has been developed in the framework of this PhD, for the experimental determination of (n,a) cross-sections at the neutron time-of-flight facility n_TOF at CERN. The 59Ni(n,a)56Fe cross-section, which is relevant for astrophysical questions as well as for risk-assessment studies in nuclear technology, has been measured in order to validate the applicability of the detector for such experiments. The thesis is divided in four parts. In the introductory part the motivation for measuring (n,a) cross-sections, the experimental challenges for such measurements and the reasons for choosing the CVD diamond technology for the detector are given. This is followed by the presentation of the n_TOF facility, an introduction to neutron-induced nuclear reactions and a brief summary of the interaction of particles with matter. The CVD diamond technology and the relevant matters related to electronics are given as well in this first part of the t...

  5. RF characteristic of MESFET on H-terminated DC arc jet CVD diamond film

    International Nuclear Information System (INIS)

    Liu, J.L.; Li, C.M.; Zhu, R.H.; Guo, J.C.; Chen, L.X.; Wei, J.J.; Hei, L.F.; Wang, J.J.; Feng, Z.H.; Guo, H.; Lv, F.X.

    2013-01-01

    Diamond has been considered to be a potential material for high-frequency and high-power electronic devices due to the excellent electrical properties. In this paper, we reported the radio frequency (RF) characteristic of metal-semiconductor field effect transistor (MESFET) on polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD). First, 4 in polycrystalline diamond films were deposited by DC arc jet CVD in gas recycling mode with the deposition rate of 14 μm/h. Then the polished diamond films were treated by microwave hydrogen plasma and the 0.2 μm-gate-length MESFET was fabricated by using Au mask photolithography and electron beam (EB) lithography. The surface conductivity of the H-terminated diamond film and DC and RF performances of the MESFET were characterized. The results demonstrate that, the carrier mobility of 24.6 cm 2 /V s and the carrier density of 1.096 × 10 13 cm −2 are obtained on the surface of H-terminated diamond film. The FET shows the maximum transition frequency (f T ) of 5 GHz and the maximum oscillation frequency (f max ) of 6 GHz at V GS = −0.5 V and V DS = −8 V, which indicates that H-terminated DC arc jet CVD polycrystalline diamond is suitable for the development of high frequency devices.

  6. Coffee consumption is not associated with prevalent subclinical cardiovascular disease (CVD) or the risk of CVD events, in nonalcoholic fatty liver disease: Results from the multi-ethnic study of atherosclerosis

    Science.gov (United States)

    Atherosclerosis and its clinical sequelae represent the leading cause of mortality among patients with nonalcoholic fatty liver disease (NAFLD). While epidemiologic data support the hepatoprotective benefits of coffee in NAFLD, whether coffee improves NAFLD-associated Cardiovascular Disease (CVD) ri...

  7. Validation of a model to investigate the effects of modifying cardiovascular disease (CVD risk factors on the burden of CVD: the rotterdam ischemic heart disease and stroke computer simulation (RISC model

    Directory of Open Access Journals (Sweden)

    van Kempen Bob JH

    2012-12-01

    Full Text Available Abstract Background We developed a Monte Carlo Markov model designed to investigate the effects of modifying cardiovascular disease (CVD risk factors on the burden of CVD. Internal, predictive, and external validity of the model have not yet been established. Methods The Rotterdam Ischemic Heart Disease and Stroke Computer Simulation (RISC model was developed using data covering 5 years of follow-up from the Rotterdam Study. To prove 1 internal and 2 predictive validity, the incidences of coronary heart disease (CHD, stroke, CVD death, and non-CVD death simulated by the model over a 13-year period were compared with those recorded for 3,478 participants in the Rotterdam Study with at least 13 years of follow-up. 3 External validity was verified using 10 years of follow-up data from the European Prospective Investigation of Cancer (EPIC-Norfolk study of 25,492 participants, for whom CVD and non-CVD mortality was compared. Results At year 5, the observed incidences (with simulated incidences in brackets of CHD, stroke, and CVD and non-CVD mortality for the 3,478 Rotterdam Study participants were 5.30% (4.68%, 3.60% (3.23%, 4.70% (4.80%, and 7.50% (7.96%, respectively. At year 13, these percentages were 10.60% (10.91%, 9.90% (9.13%, 14.20% (15.12%, and 24.30% (23.42%. After recalibrating the model for the EPIC-Norfolk population, the 10-year observed (simulated incidences of CVD and non-CVD mortality were 3.70% (4.95% and 6.50% (6.29%. All observed incidences fell well within the 95% credibility intervals of the simulated incidences. Conclusions We have confirmed the internal, predictive, and external validity of the RISC model. These findings provide a basis for analyzing the effects of modifying cardiovascular disease risk factors on the burden of CVD with the RISC model.

  8. Contribution of DIAMANT and EUROGAM detectors association to the study of heavy ion-induced fusion-evaporation reactions. Application to the de-excitation study of 90Ru compound nucleus formed in the 32S + 58Ni reaction at 120 MeV

    International Nuclear Information System (INIS)

    Bourgine, Frederic

    1996-01-01

    For the first time, the sensitivity of statistical evaporation model has been established in detail from 1 H and 4 He energy distributions analysis for different exit channels. The association of the light charged particle multidetector DIAMANT and the γ-spectrometer EUROGAM II shows that precise study of the compound nucleus high spin states deexcitation can be done for small particle channels. These channels are fed by the biggest angular momentum values of the compound nucleus. The analysis of pα channel in 32 S + 58 Ni at 120 MeV reaction exhibits that a particles have an energy distribution which leads to an entry region of the residual nucleus 85 Nb parallel to the yrast line. (author) [fr

  9. Laser-Directed CVD 3D Printing System for Refractory Metal Propulsion Hardware, Phase II, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this work, Ultramet is developing a three-dimensional (3D) laser-directed chemical vapor deposition (CVD) additive manufacturing system to build free-form...

  10. Industrial science and technology research and development project of university cooperative type in fiscal 2000. Report on achievements in semiconductor device manufacturing processes using Cat-CVD method (Semiconductor device manufacturing processes using Cat-CVD method); 2000 nendo daigaku renkeigata sangyo kagaku gijutsu kenkyu kaihatsu project. Cat-CVD ho ni yoru handotai device seizo process seika hokokusho (Cat-CVD ho ni yoru handotai device seizo process)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The catalytic chemical vapor deposition (Cat-CVD) method is a low-temperature thin film depositing technology that can achieve improvement in quality of semiconductor thin films and can perform inexpensive film deposition in a large area. The present project is composed of the basic research and development theme and the demonstrative research and development theme for the Cat-CVD method. This report summarizes the achievements in fiscal 2000 centering on the former theme. Discussions were given on the following five areas: 1) simulation on film thickness distribution in the Cat-CVD method, 2) life extension by preventing the catalyst converting into silicide and development of a catalyst integrated shear head, 3) vapor diagnosis in the film forming process by the Cat-CVD method using silane, hydrogen and ammonia, 4) a technology for high-speed deposition of hydrogenated amorphous silicon films for solar cells using the Cat-CVD method, and the low-temperature silicon oxide nitriding technology using heated catalysts, and 5) discussions on compatibility of transparent oxide electrode materials to the process of manufacturing thin-film silicon-based solar cells by using the Cat-CVD method. (NEDO)

  11. TL and LOE dosimetric evaluation of diamond films exposed to beta and ultraviolet radiation; Evaluacion dosimetrica TL y LOE de peliculas de diamante expuestas a radiacion beta y ultravioleta

    Energy Technology Data Exchange (ETDEWEB)

    Preciado F, S.; Melendrez, R.; Chernov, V.; Barboza F, M. [Universidad de Sonora, A.P. 13 y A.P. 5-088, 83000 Hermosillo, Sonora (Mexico); Schreck, M. [Universitaet Augsburg, Institut fuer Physik D-86135 (Germany); Cruz Z, E. [ICN, UNAM, 04500 Mexico D.F. (Mexico)

    2005-07-01

    The diamond possesses a privileged position regarding other materials of great technological importance. Their applications go from the optics, microelectronics, metals industry, medicine and of course as dosemeter, in the registration and detection of ionizing and non ionizing radiation. In this work the results of TL/LOE obtained in two samples of diamond of 10 {mu}m thickness grown by the chemical vapor deposition method (CVD) assisted by microwave plasma. The films were deposited in a silicon substrate (001) starting from a mixture of gases composed of CH{sub 4}/H{sub 2} and 750 ppm of molecular nitrogen as dopant. The samples were exposed to beta radiation (Sr{sup 90}/ Y{sup 90}) and ultraviolet, being stimulated later on thermal (TL) and optically (LOE) to evaluate their dosimetric properties. The sample without doping presented high response TL/LOE to the ultraviolet and beta radiation. The TL glow curve of the sample without doping showed two TL peaks with second order kinetics in the range of 520 to 550 K, besides a peak with first order kinetics of more intensity around 607 K. The TL efficiency of the non doped sample is bigger than the doped with nitrogen; however the LOE efficiency is similar in both samples. The results indicate that the CVD diamond possesses excellent perspectives for dosimetric applications, with special importance in radiotherapy due to it is biologically compatible with the human tissue. (Author)

  12. Fabrication of cerium-doped yttrium aluminum garnet thin films by a mist CVD method

    Energy Technology Data Exchange (ETDEWEB)

    Murai, Shunsuke, E-mail: murai@dipole7.kuic.kyoto-u.ac.jp; Sato, Takafumi; Yao, Situ; Kamakura, Ryosuke; Fujita, Koji; Tanaka, Katsuhisa

    2016-02-15

    We synthesized thin films, consisting of yttrium aluminum garnet doped with Ce{sup 3+} (YAG:Ce), using the mist chemical vapor deposition (CVD) method, which allows the fabrication of high-quality thin films under atmospheric conditions without the use of vacuum equipment. Under a deposition rate of approximately 1 μm/h, the obtained thin films had a typical thickness of 2 μm. The XRD analysis indicated that the thin films consisted of single-phase YAG:Ce. The Rutherford backscattering confirmed the stoichiometry; the composition of the film was determined to be (Y, Ce){sub 3}Al{sub 5}O{sub 12}, with a Ce content of Ce/(Y+Ce)=2.5%. The YAG:Ce thin films exhibited fluorescence due to the 5d–4f electronic transitions characteristic of the Ce ions occupying the eight-coordinated dodecahedral sites in the YAG lattice. - Highlights: • We have synthesized thin films of yttrium aluminum garnet doped with Ce{sup 3+} (YAG:Ce) by using a mist chemical vapor deposition (CVD) method for the first time. • The thickness of the single-phase and stoichiometric thin film obtained by 2 h deposition and following heat treatments is 2 μm. • The thin film is porous but optically transparent, and shows yellow fluorescence upon irradiation with a blue light. • Mist-CVD is a green and sustainable technique that allows fabrication of high-quality thin films at atmospheric conditions without vacuum equipment.

  13. Synthesis of graphene on nickel films by CVD method using methane

    International Nuclear Information System (INIS)

    Castro, Manuela O. de; Liebold-Ribeiro, Yvonne; Barros, Eduardo B.; Salomao, Francisco C.C.; Mendes Filho, Josue; Souza Filho, Antonio G.; Chesman, Carlos

    2011-01-01

    Full text: Nanomaterials have opened up many possibilities for groundbreaking innovations in various technologies of modern society. One key example is graphene, which is composed of one-atom-thick sheet of sp2-bonded carbon atoms, arranged in a hexagonal symmetry. However, real world applications of graphene require well-established and large synthesis techniques. The so-called Chemical Vapor Deposition (CVD) is one of the most promising method for synthesizing graphene. The general idea of this technique is to dissolve carbon atoms inside a transition metal melt at a certain temperature, then allowing the dissolved carbon to precipitate at lower temperatures as single layer graphene (SLG). In the present work, we used the CVD method and methane gas as carbon source for the synthesis of graphene on silicon (Si) substrates (300nm thermal oxide) covered with sputtered nickel (Ni) films as catalyst. In order to achieve large-area and defect-free graphene sheets the influence of the different growth parameters (growth temperature and time, gas flow of methane, film thickness and grain size of Ni) on quality and quantity of graphene growth were studied. The obtained graphene films were transferred to a silicon substrate by the polymer coating process, using polymethyl-methacrylate (PMMA) as coating. In order to characterize the transferred graphene we used Scanning Electron Microscopy (SEM), Raman Spectroscopy, Optical Microscopy and Atomic Force Microscopy (AFM). The results show the influence of CVD process parameters on the quality and quantity of graphene growth in our experimental conditions. Acknowledgments: The authors thank Brazilian agencies CNPq and FUNCAP for financial support and Alfonso Reina (MIT, USA) for helpful discussions. (author)

  14. Use of Kelvin probe force microscopy for identification of CVD grown graphene flakes on copper foil

    Science.gov (United States)

    Kumar, Rakesh; Mehta, B. R.; Kanjilal, D.

    2017-05-01

    Graphene flakes have been grown by chemical vapour deposition (CVD) method on Cu foils. The obtained graphene flakes have been characterized by optical microscopy, field emission scanning electron microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The graphene flakes grown on Cu foil comprise mainly single layer graphene and confirm that the nucleation for graphene growth starts very quickly. Moreover, KPFM has been found to be a valuable technique to differentiate between covered and uncovered portion of Cu foil by graphene flakes deposited for shorter duration. The results show that KPFM can be a very useful technique in understanding the mechanism of graphene growth.

  15. Ballistic Transport Exceeding 28 μm in CVD Grown Graphene.

    Science.gov (United States)

    Banszerus, Luca; Schmitz, Michael; Engels, Stephan; Goldsche, Matthias; Watanabe, Kenji; Taniguchi, Takashi; Beschoten, Bernd; Stampfer, Christoph

    2016-02-10

    We report on ballistic transport over more than 28 μm in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit carrier mobilities of up to three million cm(2)/(Vs). The ballistic nature of charge transport is probed by measuring the bend resistance in cross- and square-shaped devices. Temperature-dependent measurements furthermore prove that ballistic transport is maintained exceeding 1 μm up to 200 K.

  16. Role of biomarkers in predicting CVD risk in the setting of HIV infection?

    DEFF Research Database (Denmark)

    Worm, Signe W; Hsue, Priscilla

    2010-01-01

    with risk of CVD. Biomarkers associated with inflammation such as C-reactive protein and interleukin-6 have been suggested to improve risk stratification among intermediate-risk persons; however, their routine use is not recommended in the general population. Both biomarkers have recently been reported......-infected population and will increase as this population continues to age. Identification of intermediate-risk individuals using biomarkers will be an important tool for clinicians in the future to be able to treat HIV-infected individuals aggressively. Future studies of biomarkers among individuals with HIV...

  17. Fabrication and characteristics of self-assembly nano-polystyrene films by laser induced CVD

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Tingting [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Cai, Congzhong [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Peng, Liping [Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Wu, Weidong, E-mail: wuweidongding@163.com [Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, CAEP, Mianyang 621900 (China)

    2013-10-01

    The self-assembly nano-polystyrene (PS) films have been prepared by laser induced CVD at room temperature. The XPS, Raman and UV–vis absorption spectra all indicated that the films were PS. The optical properties, microstructure and controllable nanostructure of PS films have been investigated. Dewetting-like microstructure in PS films was investigated and uniform island structures with a diameter of about 200 nm were observed at the deposition pressure of 14 Pa. The films possess good toughness and precisely controlled thicknesses. The free-standing PS films with thickness of 10 nm could be obtained by this method though a series of process.

  18. Ethylene Gas Sensing Properties of Tin Oxide Nanowires Synthesized via CVD Method

    Science.gov (United States)

    Akhir, Maisara A. M.; Mohamed, Khairudin; Rezan, Sheikh A.; Arafat, M. M.; Haseeb, A. S. M. A.; Uda, M. N. A.; Nuradibah, M. A.

    2018-03-01

    This paper studies ethylene gas sensing performance of tin oxide (SnO2) nanowires (NWs) as sensing material synthesized using chemical vapor deposition (CVD) technique. The effect of NWs diameter on ethylene gas sensing characteristics were investigated. SnO2 NWs with diameter of ∼40 and ∼240 nm were deposited onto the alumina substrate with printed gold electrodes and tested for sensing characteristic toward ethylene gas. From the finding, the smallest diameter of NWs (42 nm) exhibit fast response and recovery time and higher sensitivity compared to largest diameter of NWs (∼240 nm). Both sensor show good reversibility features for ethylene gas sensor.

  19. Optical characterization of a-Si:H thin films grown by Hg-Photo-CVD

    International Nuclear Information System (INIS)

    Barhdadi, A.; Karbal, S.; M'Gafad, N.; Benmakhlouf, A.; Chafik El Idrissi, M.; Aka, B.M.

    2006-08-01

    Mercury-Sensitized Photo-Assisted Chemical Vapor Deposition (Hg-Photo-CVD) technique opens new possibilities for reducing thin film growth temperature and producing novel semiconductor materials suitable for the future generation of high efficiency thin film solar cells onto low cost flexible plastic substrates. This paper provides some experimental data resulting from the optical characterization of hydrogenated amorphous silicon thin films grown by this deposition technique. Experiments have been performed on both as-deposited layers and thermal annealed ones. (author) [fr

  20. Effect of pretreatment and deposition parameters on diamond nucleation in CVD

    International Nuclear Information System (INIS)

    Nazim, E.; Izman, S.; Ourdjini, A.; Shaharoun, A.M.

    2007-01-01

    Chemical vapour deposition (CVD) of diamond films on cemented carbide (WC) has aroused great interest in recent years. The combination of toughness from the WC and the high hardness of diamond results in outstanding wear resistance. This will increase the lifetime and better technical performance of the components made of diamond coated carbide. One of the important steps in the growth of diamond film is the nucleation of diamond as its density strongly influences the diamond growth process, film quality and morphology. In this paper the various effects of surface pretreatment and diamond deposition conditions on the diamond nucleation density are reviewed. (author)

  1. A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD Method

    Directory of Open Access Journals (Sweden)

    Yehia M. Manawi

    2018-05-01

    Full Text Available Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs, carbon nanofibers (CNFs, graphene, carbide-derived carbon (CDC, carbon nano-onion (CNO and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research.

  2. A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD) Method

    Science.gov (United States)

    Manawi, Yehia M.; Samara, Ayman; Al-Ansari, Tareq; Atieh, Muataz A.

    2018-01-01

    Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD) method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, carbide-derived carbon (CDC), carbon nano-onion (CNO) and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research. PMID:29772760

  3. The study on diamond-coated insert by DC plasma jet CVD

    International Nuclear Information System (INIS)

    Zhou Kesong; Dai Mingjiang; Song Jinbing; Kuang Tongchun; Liu Zhengyi

    2001-01-01

    Diamond coating were deposited on cemented carbide inserts by DC plasma jet CVD. The cemented carbide inserts were pretreated by methods including chemical etching of Co, Ar/H 2 plasma etching. The characteristics of diamond film, interface structure, adhesion strength and film stress were analysized by different methods such as SEM, XRD, Raman spectrum etc. A comparing experiment of cutting Al - 22 % Si alloy was carried out with diamond-coated cemented carbide inserts and uncoated cemented carbide inserts. The results show that the diamond-coated cemented carbide insert has a great advantage for cutting abrasive high content Al - Si alloy. (author)

  4. Growth, characterization and properties of CVD diamond films for applications as radiation detectors

    International Nuclear Information System (INIS)

    Sciorti, S.

    1999-01-01

    The aim of the work is to give a picture of the current state of the art of CVD (chemical vapour deposition) diamond. The interest is due to the capability to grow over large areas a material with physical properties suitable for an impressive number of applications. The authors focuses on the potential of diamond as a radiation detector and gets into details of the huge field that extends from the thermochemistry of the deposition process to the test of a diamond-based tracker with a fast readout electronics

  5. High-Resolution Energy and Intensity Measurements with CVD Diamond at REX-ISOLDE

    CERN Document Server

    Griesmayer, E; Dobos, D; Wenander, F; Bergoz, J; Bayle, H; Frais-Kölbl, H; Leinweber, J; Aumeyr, T; CERN. Geneva. BE Department

    2009-01-01

    A novel beam instrumentation device for the HIE-REX (High In-tensity and Energy REX) upgrade has been developed and tested at the On-Line Isotope Mass Separator ISOLDE, located at the European Laboratory for Particle Physics (CERN). This device is based on CVD diamond detector technology and is used for measuring the beam intensity, particle counting and measuring the energy spectrum of the beam. An energy resolution of 0.6% was measured at a carbon ion energy of 22.8 MeV. This corresponds to an energy spread of ± 140 keV.

  6. TEORIAS DE INTERNACIONALIZAÇÃO E APLICAÇÃO EM PAÍSES EMERGENTES: UMA ANÁLISE CRÍTICA

    Directory of Open Access Journals (Sweden)

    WALTER F. ARAUJO DE MORAES

    2006-01-01

    Full Text Available Neste artigo são apresentadas e discutidas sete teorias de internacionalização, a saber: oModelo do Ciclo de Vida do Produto, Uppsala – Escola Nórdica de Negócios Internacionais,Relacionado à Inovação, Escolha Adaptativa, Paradigma Eclético de Internalização (OLI,Modelo de Internacionalização Baseado em Recursos (RBV e o Modelo Diamante. Oobjetivo é analisar criticamente estas teorias, propondo uma união entre alguns de seusconceitos-chave para um melhor entendimento do processo de internacionalização incluindo acontexto dos países emergentes. Ademais, questiona-se a aplicação destes modelos, elaboradosem países desenvolvidos, em países emergentes sem uma análise crítica, buscando-se aconvergência sem a percepção dos diferentes contextos e timing de internacionalização, já queo protecionismo instaurado tornou tardia a entrada destes países no mercado internacional.

  7. Joint association of physical activity/screen time and diet on CVD risk factors in 10-year-old children.

    Science.gov (United States)

    Drenowatz, Clemens; Carlson, Joseph J; Pfeiffer, Karin A; Eisenmann, Joey C

    2012-12-01

    The increasing prevalence of childhood overweight and obesity has been associated with an increased risk for cardiovascular disease (CVD). While several studies examined the effect of single behaviors such as physical activity (PA), sedentary behavior or diet on CVD risk, there is a lack of research on combined associations, specifically in children. Therefore, the purpose of this study was to examine the joint association of PA or screen time (ST) and diet on CVD risk factors in children. PA, STand diet were assessed via questionnaire in 210 fifth grade students (age: 10.6 ± 0.4 years). The healthy eating index (HEI) was subsequently calculated as indicator for diet quality. Height, weight, % body fat, and resting blood pressure were measured according to standard procedures and blood samples obtained via fingerprick were assayed for blood lipids. Total cholesterol HDL ratio (TC:HDL), mean arterial pressure (MAP), and % body fat were used as indicators of CVD risk. 55% of children did not meet current PA recommendations on at least 5 days/week and 70% exceeded current recommendations for ST. Further, only 2.5% possessed a "good" diet (HEI> 80). There was no significant association of PA or STand diet on CVD risk score. Neither TC:HDL, MAP, and % body fat nor the total CVD risk score was significantly correlated with diet, PA, or ST. Children in the high PA group, however, had significantly better diet scores. Despite the fact that self-reported PA, ST, or dietary intake were not directly related to CVD risk in this sample, higher activity levels were associated with a healthier diet and lower ST indicating an overall healthier lifestyle of this subgroup.

  8. Evaluation of <em>HER2em> Gene Amplification in Breast Cancer Using Nuclei Microarray <em>in em>S>itu em>Hybridization

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    2012-05-01

    Full Text Available Fluorescence<em> em>>in situ em>hybridization (FISH assay is considered the “gold standard” in evaluating <em>HER2/neu (HER2em> gene status. However, FISH detection is costly and time consuming. Thus, we established nuclei microarray with extracted intact nuclei from paraffin embedded breast cancer tissues for FISH detection. The nuclei microarray FISH (NMFISH technology serves as a useful platform for analyzing <em>HER2em> gene/chromosome 17 centromere ratio. We examined <em>HER2em> gene status in 152 cases of invasive ductal carcinomas of the breast that were resected surgically with FISH and NMFISH. <em>HER2em> gene amplification status was classified according to the guidelines of the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP. Comparison of the cut-off values for <em>HER2em>/chromosome 17 centromere copy number ratio obtained by NMFISH and FISH showed that there was almost perfect agreement between the two methods (κ coefficient 0.920. The results of the two methods were almost consistent for the evaluation of <em>HER2em> gene counts. The present study proved that NMFISH is comparable with FISH for evaluating <em>HER2em> gene status. The use of nuclei microarray technology is highly efficient, time and reagent conserving and inexpensive.

  9. A New Natural Lactone from <em>Dimocarpus> <em>longan> Lour. Seeds

    Directory of Open Access Journals (Sweden)

    Zhongjun Li

    2012-08-01

    Full Text Available A new natural product named longanlactone was isolated from <em>Dimocarpus> <em>longan> Lour. seeds. Its structure was determined as 3-(2-acetyl-1<em>H>-pyrrol-1-yl-5-(prop-2-yn-1-yldihydrofuran-2(3H-one by spectroscopic methods and HRESIMS.

  10. VO{sub x} effectively doping CVD-graphene for transparent conductive films

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Qinghua; Shi, Liangjing [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhang, Qinghong [State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620 (China); Wang, Weiqi; Zheng, Huifeng [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhang, Yuzhi [The Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences,1295 Dingxi Road, Shanghai 200050 (China); Liu, Yangqiao, E-mail: yqliu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Sun, Jing, E-mail: jingsun@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2016-11-30

    Highlights: • Doping process operated easily. • Sheet resistance decreased efficiently after doping. • Sheet resistance of doped graphene is stable after exposed in the air. • Mechanism of doping process is studied. - Abstract: Chemical vapor deposition(CVD)-synthesized graphene is potentially an alternative for tin-doped indium oxide (ITO) transparent conductive films (TCFs), however its sheet resistance is still too high to meet many demands. Vanadium oxide has been widely applied as smart window materials, however, no study has been reported to use it as dopant to improve the conductivity of graphene TCFs. In this study, we firstly reported that VO{sub x} doping can effectively lower the sheet resistance of CVD-graphene films while keeping its good optical properties, whose transmittance is as high as 86–90%. The optimized VO{sub x}-doped graphene exhibits a sheet resistance as low as 176 Ω/□, which decreases by 56% compared to the undoped graphene films. The doping process is convenient, stable, economical and easy to operate. What is more, VO{sub x} can effectively increase the work function(WF) of the film, making it more appropriate for use in solar cells. The evolution of the VO{sub x} species annealed at different temperatures below 400 °C has been detailed studied for the first time, based on which the doping mechanism is proposed. The prepared VO{sub x} doped graphene is expected to be a promising candidate for transparent conductive film purposes.

  11. A novel Mo-W interlayer approach for CVD diamond deposition on steel

    Energy Technology Data Exchange (ETDEWEB)

    Kundrát, Vojtěch; Sullivan, John; Ye, Haitao, E-mail: h.ye@aston.ac.uk [School of Engineering and Applied Science, Aston University, Birmingham, B4 7ET (United Kingdom); Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin [Miba Coating Group: Teer Coatings Ltd, West-Stone-House, West-Stone, Berry-Hill-Industrial-Estate, WR9 9AS, Droitwich (United Kingdom)

    2015-04-15

    Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) – tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

  12. Controlled growth of CNT in mesoporous AAO through optimized conditions for membrane preparation and CVD operation

    Energy Technology Data Exchange (ETDEWEB)

    Ciambelli, P; Sarno, M; Leone, C; Sannino, D [Department of Chemical and Food Engineering, University of Salerno, I-84084 Fisciano (Italy); Arurault, L; Fontorbes, S; Datas, L; Lenormand, P; Le Blond Du Plouy, S, E-mail: msarno@unisa.it, E-mail: arurault@chimie.ups-tlse.fr [Universite de Toulouse, CIRIMAT, UPS/INPT/CNRS, LCMIE, F-31062 Toulouse Cedex 9 (France)

    2011-07-01

    Anodic aluminium oxide (RAAO) membranes with a mesoporous structure were prepared under strictly controlling experimental process conditions, and physically and chemically characterized by a wide range of experimental techniques. Commercial anodic aluminium oxide (CAAO) membranes were also investigated for comparison. We demonstrated that RAAO membranes have lower content of both water and phosphorus and showed better porosity shape than CAAO. The RAAO membranes were used for template growth of carbon nanotubes (CNT) inside its pores by ethylene chemical vapour deposition (CVD) in the absence of a catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and an external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity and quality of CNTs in terms of diameter, length and arrangement (i.e. number of tubes for each channel) were optimized by investigating the effect of changing the experimental conditions for the CVD process. We showed that upon thermal treatment RAAO membranes were made up of crystallized allotropic alumina phases, which govern the subsequent CNT growth, because of their catalytic activity, likely due to their Lewis acidity. The strict control of experimental conditions for membrane preparation and CNT growth allowed us to enhance the carbon structural order, which is a critical requisite for CNT application as a substitute for copper in novel nano-interconnects.

  13. GaN CVD Reactions: Hydrogen and Ammonia Decomposition and the Desorption of Gallium

    International Nuclear Information System (INIS)

    Bartram, Michael E.; Creighton, J. Randall

    1999-01-01

    Isotopic labeling experiments have revealed correlations between hydrogen reactions, Ga desorption, and ammonia decomposition in GaN CVD. Low energy electron diffraction (LEED) and temperature programmed desorption (TPD) were used to demonstrate that hydrogen atoms are available on the surface for reaction after exposing GaN(0001) to deuterium at elevated temperatures. Hydrogen reactions also lowered the temperature for Ga desorption significantly. Ammonia did not decompose on the surface before hydrogen exposure. However, after hydrogen reactions altered the surface, N 15 H 3 did undergo both reversible and irreversible decomposition. This also resulted in the desorption of N 2 of mixed isotopes below the onset of GaN sublimation, This suggests that the driving force of the high nitrogen-nitrogen bond strength (226 kcal/mol) can lead to the removal of nitrogen from the substrate when the surface is nitrogen rich. Overall, these findings indicate that hydrogen can influence G-aN CVD significantly, being a common factor in the reactivity of the surface, the desorption of Ga, and the decomposition of ammonia

  14. CVD growth of graphene under exfoliated hexagonal boron nitride for vertical hybrid structures

    International Nuclear Information System (INIS)

    Wang, Min; Jang, Sung Kyu; Song, Young Jae; Lee, Sungjoo

    2015-01-01

    Graphical abstract: We have demonstrated a novel yet simple method for fabricating graphene-based vertical hybrid structures by performing the CVD growth of graphene at an h-BN/Cu interface. Our systematic Raman measurements combined with plasma etching process indicate that a graphene film is grown under exfoliated h-BN rather than on its top surface, and that an h-BN/graphene vertical hybrid structure has been fabricated. Electrical transport measurements of this h-BN/graphene, transferred on SiO2, show the carrier mobility up to approximately 2250 cm 2 V −1 s −1 . The developed method would enable the exploration of the possibility of novel hybrid structure integration with two-dimensional material systems. - Abstract: We have demonstrated a novel yet simple method for fabricating graphene-based vertical hybrid structures by performing the CVD growth of graphene at an h-BN/Cu interface. Our systematic Raman measurements combined with plasma etching process indicate that a graphene film is grown under exfoliated h-BN rather than on its top surface, and that an h-BN/graphene vertical hybrid structure has been fabricated. Electrical transport measurements of this h-BN/graphene, transferred on SiO 2 , show the carrier mobility up to approximately 2250 cm 2 V −1 s −1 . The developed method would enable the exploration of the possibility of novel hybrid structure integration with two-dimensional material systems

  15. CVD tungsten metallization and electron beam lithography for fabricating submicron interconnects for advanced ULSI

    International Nuclear Information System (INIS)

    Wilson, S.R.; Mattox, R.J.

    1988-01-01

    CVD W (0.45μm thick) and CVD W (0.25μm thick) strapped by Al (0.5μm thick) have been used as metal 1 systems. Electrical and physical data are presented from experiments exploring the effects of processing issues with both e-beam and stepper lithography as well as dry etch chemistry on both metal systems. The special issues encountered with the thick tungsten processing were: (i) Significant e-beam proximity related problems as compared to the sandwich metal layers. The resultant e-beam proximity problem contributed to a high level of metal bridging and poor CD control. (ii) Multiple etch related problems due to mask failure and a lack of etch selectivity. The multilevel masks utilized, consisting of photoresist and plasma enhanced oxide (PEO), failed due to the poor etch selectivity. Poor etch selectivity with respect to the underlying oxide was also observed. These issues were addressed with thicker organic and PEO mask layers as well as changes in etch chemistry. These thick layers were successful in preventing the loss of the mask during etch., but caused problems in the e-beam CD control and did not prevent the degradation of the underlying glass. A higher selectivity etch was developed which greatly reduced the underlying dielectric damage and also allowed the use of the thinner organic and PEO hardmask layers without mask failure

  16. A novel Mo-W interlayer approach for CVD diamond deposition on steel

    Science.gov (United States)

    Kundrát, Vojtěch; Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin; Sullivan, John; Ye, Haitao

    2015-04-01

    Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) - tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

  17. Surface structure deduced differences of copper foil and film for graphene CVD growth

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Junjun [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Hu, Baoshan, E-mail: hubaoshan@cqu.edu.cn [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wei, Zidong; Jin, Yan [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Luo, Zhengtang [Department of Chemical and Biomolecular Engineering, The Hongkong University of Science and Technology, Kowloon (Hong Kong); Xia, Meirong [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Pan, Qingjiang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Heilongjiang University, Harbin 150080 (China); Liu, Yunling [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

    2014-05-01

    Highlights: • We demonstrate the significant differences between Cu foil and film in the surface morphology and crystal orientation distribution. • The different surface structure leads to the distinctive influences of the CH₄ and H₂ concentrations on the thickness and quality of as-grown graphene. • Nucleation densities and growth rate differences at the initial growth stages on the Cu foil and film were investigated and discussed. Abstract: Graphene was synthesized on Cu foil and film by atmospheric pressure chemical vapor deposition (CVD) with CH₄ as carbon source. Electron backscattered scattering diffraction (EBSD) characterization demonstrates that the Cu foil surface after the H₂-assisted pre-annealing was almost composed of Cu(1 0 0) crystal facet with larger grain size of ~100 μm; meanwhile, the Cu film surface involved a variety of crystal facets of Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0), with the relatively small grain size of ~10 μm. The different surface structure led to the distinctive influences of the CH₄ and H₂ concentrations on the thickness and quality of as-grown graphene. Further data demonstrate that the Cu foil enabled more nucleation densities and faster growth rates at the initial growth stages than the Cu film. Our results are beneficial for understanding the relationship between the metal surface structure and graphene CVD growth.

  18. Influence of tungsten on the carbon nanotubes growth by CVD process

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, Mariano [Instituto de Fisicoquimica de Materiales, Ambiente y Energia, CONICET-UBA, Pabellon II, Ciudad Universitaria (1428) Bs As (Argentina); LP and MC, Dep. De Fisica, FCEyN-UBA, Pabellon 1, Ciudad Universitaria (1428) Bs As (Argentina)], E-mail: mescobar@qi.fcen.uba.ar; Rubiolo, Gerardo H. [LP and MC, Dep. De Fisica, FCEyN-UBA, Pabellon 1, Ciudad Universitaria (1428) Bs As (Argentina); Unidad de Actividad Materiales, CNEA, Av. Gral. Paz 1499, San Martin (1650), Bs As (Argentina); Moreno, M. Sergio [Centro Atomico Bariloche, (8400) S.C. de Bariloche, Rio Negro (Argentina); Goyanes, Silvia [LP and MC, Dep. De Fisica, FCEyN-UBA, Pabellon 1, Ciudad Universitaria (1428) Bs As (Argentina); Candal, Roberto [Instituto de Fisicoquimica de Materiales, Ambiente y Energia, CONICET-UBA, Pabellon II, Ciudad Universitaria (1428) Bs As (Argentina)

    2009-06-24

    The effect of tungsten (W) on the growth of multi-walled carbon nanotubes (MWNTs) using the chemical vapour deposition (CVD) process over a metal Fe-W catalyst incorporated into a silica matrix is reported. A W molar content in Fe/SiO{sub 2} up to 10% was studied. The incorporation of only 2% of W substantially modifies the crystalline phases and the crystalline degree of the catalyst during the MWNTs synthesis. This fact seems to have a strong influence on the type and yield of the carbonaceous species obtained by the CVD of acetylene, at 600 deg. C and 180 Torr, over each catalyst. Tungsten interacts with iron within the matrix, diminishing the catalytic activity of the metal nanoparticles, and both, carbon nanotubes and carbon nanofibers, are obtained when tungsten is present. The results obtained support the hypothesis of a base growth model for carbon nanotubes indicating a strong interaction between silica matrix and Fe/W nanoparticles, independently of the content of W.

  19. Influence of tungsten on the carbon nanotubes growth by CVD process

    International Nuclear Information System (INIS)

    Escobar, Mariano; Rubiolo, Gerardo H.; Moreno, M. Sergio; Goyanes, Silvia; Candal, Roberto

    2009-01-01

    The effect of tungsten (W) on the growth of multi-walled carbon nanotubes (MWNTs) using the chemical vapour deposition (CVD) process over a metal Fe-W catalyst incorporated into a silica matrix is reported. A W molar content in Fe/SiO 2 up to 10% was studied. The incorporation of only 2% of W substantially modifies the crystalline phases and the crystalline degree of the catalyst during the MWNTs synthesis. This fact seems to have a strong influence on the type and yield of the carbonaceous species obtained by the CVD of acetylene, at 600 deg. C and 180 Torr, over each catalyst. Tungsten interacts with iron within the matrix, diminishing the catalytic activity of the metal nanoparticles, and both, carbon nanotubes and carbon nanofibers, are obtained when tungsten is present. The results obtained support the hypothesis of a base growth model for carbon nanotubes indicating a strong interaction between silica matrix and Fe/W nanoparticles, independently of the content of W.

  20. Estimation of magnetic relaxation property for CVD processed YBCO-coated conductors

    International Nuclear Information System (INIS)

    Takahashi, Y.; Kiuchi, M.; Otabe, E.S.; Matsushita, T.; Shikimachi, K.; Watanabe, T.; Kashima, N.; Nagaya, S.

    2010-01-01

    Ion Beam Assist Deposition/Chemical Vapor Deposition(IBAD/CVD)-processed YBCO-coated conductors with high critical current density J c at high magnetic fields are expected to be applied to superconducting equipments such as superconducting magnetic energy storage (SMES). For application to superconducting magnet in SMES one of the most important properties for superconductors is the relaxation property of superconducting current. In this paper, the relaxation property is investigated for IBAD/CVD-processed YBCO-coated conductors of the superconducting layer in the range of 0.18-0.90 μm. This property can be quantitatively characterized by the apparent pinning potential, U 0 *. It is found that U 0 * takes a smaller value due to the two-dimensional pinning mechanism at high magnetic fields for conductor with thinner superconducting layer. Although U 0 * decreases with increasing thickness at low magnetic fields at 20 K, it increases at high magnetic fields. The results are theoretically explained by the model of the flux creep and flow based on the dimensionality of flux pinning. Scaling analysis is examined for the dependence of U 0 * on the magnetic field, temperature and the layer thickness.

  1. Low resistive edge contacts to CVD-grown graphene using a CMOS compatible metal

    Energy Technology Data Exchange (ETDEWEB)

    Shaygan, Mehrdad; Otto, Martin; Sagade, Abhay A.; Neumaier, Daniel [Advanced Microelectronic Center Aachen, AMO GmbH, Aachen (Germany); Chavarin, Carlos A. [Lehrstuhl Werkstoffe der Elektrotechnik, Duisburg-Essen Univ., Duisburg (Germany); Innovations for High Performance Microelectronics, IHP GmbH, Frankfurt (Oder) (Germany); Bacher, Gerd; Mertin, Wolfgang [Lehrstuhl Werkstoffe der Elektrotechnik, Duisburg-Essen Univ., Duisburg (Germany)

    2017-11-15

    The exploitation of the excellent intrinsic electronic properties of graphene for device applications is hampered by a large contact resistance between the metal and graphene. The formation of edge contacts rather than top contacts is one of the most promising solutions for realizing low ohmic contacts. In this paper the fabrication and characterization of edge contacts to large area CVD-grown monolayer graphene by means of optical lithography using CMOS compatible metals, i.e. Nickel and Aluminum is reported. Extraction of the contact resistance by Transfer Line Method (TLM) as well as the direct measurement using Kelvin Probe Force Microscopy demonstrates a very low width specific contact resistance down to 130 Ωμm. The contact resistance is found to be stable for annealing temperatures up to 150 C enabling further device processing. Using this contact scheme for edge contacts, a field effect transistor based on CVD graphene with a high transconductance of 0.63 mS/μm at 1 V bias voltage is fabricated. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Stress in ion-implanted CVD Si3N4 films

    International Nuclear Information System (INIS)

    EerNisse, E.P.

    1977-01-01

    The compressive stress buildup caused in chemical-vapor-deposited (CVD) Si 3 N 4 films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5 x 10 10 dyn/cm 2 , resulting in a maximum net compressive stress of 2 x 10 10 dyn/cm 2 for films on Si where the as-deposited films inherently have 1.5 x 10 10 dyn/cm 2 tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion-implantation-induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment

  3. Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD

    International Nuclear Information System (INIS)

    Park, J.H.

    1998-04-01

    In the design of liquid-metal blankets for magnetic fusion reactors, corrosion resistance of structural materials and the magnetohydrodynamic forces and their influence on thermal hydraulics and corrosion are major concerns. Electrically insulating CaO films deposited on V-4%Cr-4%Ti exhibit high-ohmic insulator behavior even though a small amount of vanadium from the alloy become incorporated into the film. However, when vanadium concentration in the film is > 15 wt.%, the film becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. The objective of this study is to evaluate electrically insulating films that were deposited on V-4%Cr-4%Ti by a reactive chemical vapor deposition (CVD) method. To this end, CaO and Ca-V-O coatings were produced on vanadium alloys by CVD and by a metallic-vapor process to investigate the electrical resistance of the coatings. The authors found that the Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film > 0.9, and semiconductor or conductor behavior when R 0.98 were exposed in liquid lithium. Based on these studies, they conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating

  4. Parametric assessments on hydrogenic species transport in CVD-diamond vacuum windows used in ITER ECRH

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, C.; Sedano, L.A.; Fernandez, A. [EURATOM-CIEMAT Association, Madrid (Spain)

    2007-07-01

    Insulators used as H and CD and Diagnostic vacuum windows (VW) in ITER may become modified by surface intake and bulk transport of hydrogenic species. VW, operating under severe radiation levels, have a primary safety role as tritium confinement barriers. Ionizing radiation enhances the (H') uptake and release at surfaces and diffusion rates in the bulk. Radiation damage modifies the material's bulk trapped inventories by increasing steady state trapping centre concentrations. An experimental programme is ongoing at CIEMAT, to quantify radiation effects on H transport characteristics and also the possible impact on the VW. The reference material for ECRH VW is CVD diamond. As a parallel activity, parametric transport assessments are being made in order to obtain a wide evaluation of permeation fluxes, ranges, and soluted/trapped inventories in CVD diamond. Transport models have been developed based on extended capabilities of finite differences integrator tool TMAP7. Special attention is paid to radiation parameters defining inputs acting on transport magnitudes. These inputs have been analysed by using ionizing/damage radiation transport tools such as MCNPX/SRIM. VW operational scenarios are discussed with special attention being paid to the ITER design assumptions for the values of H-species source terms (neutrals and implanted) in the ECRH system. The available material transport database with and without radiation is discussed and taken as reference for this parametric exercise. Permeation fluxes through base materials are shown to be below DRG limits established for ITER. (orig.)

  5. A novel Mo-W interlayer approach for CVD diamond deposition on steel

    Directory of Open Access Journals (Sweden)

    Vojtěch Kundrát

    2015-04-01

    Full Text Available Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42 substrates using a multi-structured molybdenum (Mo – tungsten (W interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

  6. Performance of CVD diamond as an optically and thermally stimulated luminescence dosemeter

    International Nuclear Information System (INIS)

    Preciado-Flores, S.; Schreck, M.; Melendrez, R.; Chernov, V.; Bernal, R.; Cruz-Vazquez, C.; Cruz-Zaragoza, E.; Barboza-Flores, M.

    2006-01-01

    Diamond is a material with extreme physical properties. Its radiation hardness, chemical inertness and tissue equivalence qualify it as an ideal material for radiation dosimetry. In the present work, the optically stimulated luminescence (OSL) and thermoluminescence (TL) characteristics of a 10 μm thick CVD diamond (polycrystalline diamond films prepared by chemical vapor deposition) film were studied in order to test its performance as a beta radiation dosemeter. The TL response is composed of four main TL glow peaks; two of these are in the range of 150-200 deg. C and two additional peaks in the 250-400 deg. C temperature range. The integrated TL as a function of radiation dose is linear up to 100 Gy and increases with increasing dose exposure. The dose dependence of the integrated OSL exhibits a similar behavior. The observed OSL/TL behavior for the CVD diamond film clearly demonstrate its capability for applications in radiation dosimetry with special relevance in medical dosimetry owing to the diamond's intrinsic material properties. (authors)

  7. Performance of CVD and CVR coated carbon-carbon in high temperature hydrogen

    Science.gov (United States)

    Adams, J. W.; Barletta, R. E.; Svandrlik, J.; Vanier, P. E.

    As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings which will be time and temperature stable at extremely high temperatures in flowing hydrogen. These coatings must protect the underlying carbon structure from attack by the hydrogen coolant. Degradation which causes small changes in the reactor component, e.g. hole diameter in the hot frit, can have a profound effect on operation. The ability of a component to withstand repeated temperature cycles is also a coating development issue. Coatings which crack or spall under these conditions would be unacceptable. While refractory carbides appear to be the coating material of choice for carbon substrates being used in PBR components, the method of applying these coatings can have a large effect on their performance. Two deposition processes for these refractory carbides, chemical vapor deposition (CVD) and chemical vapor reaction (CVR), have been evaluated. Screening tests for these coatings consisted of testing of coated 2-D and 3-D weave carbon-carbon in flowing hot hydrogen at one atmosphere. Carbon loss from these samples was measured as a function of time. Exposure temperatures up to 3,000 K were used, and samples were exposed in a cyclical fashion cooling to room temperature between exposures. The results of these measurements are presented along with an evaluation of the relative merits of CVR and CVD coatings for this application.

  8. Influence of duration time of CVD process on emissive properties of carbon nanotubes films

    Directory of Open Access Journals (Sweden)

    Stępinska Izabela

    2015-03-01

    Full Text Available In this paper various types of films made of carbon nanotubes (CNTs are presented. These films were prepared on different substrates (Al2O3, Si n-type by the two-step method. The two-step method consists of physical vapor deposition step, followed by chemical vapor deposition step (PVD/CVD. Parameters of PVD process were the same for all initial films, while the duration times of the second step - the CVD process, were different (15, 30 min.. Prepared films were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM and field emission (FE measurements. The I-E and F-N characteristics of electron emission were discussed in terms of various forms of CNT films. The value of threshold electric field ranged from few V/μm (for CNT dispersed rarely on the surface of the film deposited on Si up to ~20 V/μm (for Al2O3 substrate.

  9. Unravelling merging behaviors and electrostatic properties of CVD-grown monolayer MoS2 domains

    International Nuclear Information System (INIS)

    Hao, Song; Yang, Bingchu; Gao, Yongli

    2016-01-01

    The presence of grain boundaries is inevitable for chemical vapor deposition (CVD)-grown MoS 2 domains owing to various merging behaviors, which greatly limits its potential applications in novel electronic and optoelectronic devices. It is therefore of great significance to unravel the merging behaviors of the synthesized polygon shape MoS 2 domains. Here we provide systematic investigations of merging behaviors and electrostatic properties of CVD-grown polycrystalline MoS 2 crystals by multiple means. Morphological results exhibit various polygon shape features, ascribed to polycrystalline crystals merged with triangle shape MoS 2 single crystals. The thickness of triangle and polygon shape MoS 2 crystals is identical manifested by Raman intensity and peak position mappings. Three merging behaviors are proposed to illustrate the formation mechanisms of observed various polygon shaped MoS 2 crystals. The combined photoemission electron microscopy and kelvin probe force microscopy results reveal that the surface potential of perfect merged crystals is identical, which has an important implication for fabricating MoS 2 -based devices.

  10. Mindfulness-Based Interventions for Weight Loss and CVD Risk Management

    Science.gov (United States)

    Fulwiler, Carl; Brewer, Judson A.; Sinnott, Sinead; Loucks, Eric B.

    2017-01-01

    Obesity affects more than one-third of U.S. adults and is a major cause of preventable morbidity and mortality, primarily from cardiovascular disease. Traditional behavioral interventions for weight loss typically focus on diet and exercise habits and often give little attention to the role of stress and emotions in the initiation and maintenance of unhealthy behaviors, which may account for their modest results and considerable variability in outcomes. Stress eating and emotional eating are increasingly recognized as important targets of weight loss interventions. Mindfulness-based interventions were specifically developed to promote greater self-efficacy in coping with stress and negative emotions, and appear to be effective for a variety of conditions. In recent years researchers have begun to study mindfulness interventions for weight loss and CVD risk management. This review describes the rationale for the use of mindfulness in interventions for weight loss and CVD risk management, summarizes the research to date, and suggests priorities for future research. PMID:28405260

  11. Does productivity influence priority setting? A case study from the field of CVD prevention

    Directory of Open Access Journals (Sweden)

    Löfroth Emil

    2008-03-01

    Full Text Available Abstract In this case study, different measures aimed at preventing cardiovascular diseases (CVD in different target groups have been ranked based on cost per QALY from a health care sector perspective and from a societal perspective, respectively. The innovation in this study is to introduce a budget constraint and thereby show exactly which groups would be included or excluded in treatment or intervention programs based on the two perspectives. Approximately 90% of the groups are included in both perspectives. Mainly elderly women are excluded when the societal perspective is used and mainly middle-aged men are excluded when the health care sector perspective is used. Elderly women have a higher risk of CVD and generally lower income than middle-aged men. Thus the exclusion of older women in the societal perspective is not a trivial consequence since it is in conflict with the general interpretation of the "treatment according to need" rule, as well as societal goals regarding gender equality and fairness. On the other hand, the exclusion of working individuals in the health care perspective undermines a growth of public resources for future health care for the elderly. The extent and consequences of this conflict are unclear and empirical studies of this problem are rare.

  12. Electrical and thermal conductivity of low temperature CVD graphene: the effect of disorder

    International Nuclear Information System (INIS)

    Vlassiouk, Ivan; Datskos, Panos; Smirnov, Sergei; Ivanov, Ilia; Hensley, Dale; Lavrik, Nickolay V; Fulvio, Pasquale F; Dai Sheng; Meyer, Harry; Chi Miaofang

    2011-01-01

    In this paper we present a study of graphene produced by chemical vapor deposition (CVD) under different conditions with the main emphasis on correlating the thermal and electrical properties with the degree of disorder. Graphene grown by CVD on Cu and Ni catalysts demonstrates the increasing extent of disorder at low deposition temperatures as revealed by the Raman peak ratio, I G /I D . We relate this ratio to the characteristic domain size, L a , and investigate the electrical and thermal conductivity of graphene as a function of L a . The electrical resistivity, ρ, measured on graphene samples transferred onto SiO 2 /Si substrates shows linear correlation with L a -1 . The thermal conductivity, K, measured on the same graphene samples suspended on silicon pillars, on the other hand, appears to have a much weaker dependence on L a , close to K ∼ L a 1/3 . It results in an apparent ρ ∼ K 3 correlation between them. Despite the progressively increasing structural disorder in graphene grown at lower temperatures, it shows remarkably high thermal conductivity (10 2 -10 3 W K -1 m -1 ) and low electrical (10 3 -3 x 10 5 Ω) resistivities suitable for various applications.

  13. Optical characterization of single-crystal diamond grown by DC arc plasma jet CVD

    Science.gov (United States)

    Hei, Li-fu; Zhao, Yun; Wei, Jun-jun; Liu, Jin-long; Li, Cheng-ming; Lü, Fan-xiu

    2017-12-01

    Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition (CVD) were examined using a low-temperature photoluminescence (PL) technique. The results show that most of the nitrogen-vacancy (NV) complexes are present as NV- centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N2 incorporation and the high mobility of vacancies under growth temperatures of 950-1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy (Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition (MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV- centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.

  14. Heparin free coating on PLA membranes for enhanced hemocompatibility via iCVD

    Science.gov (United States)

    Wang, Hui; Shi, Xiao; Gao, Ailin; Lin, Haibo; Chen, Yongliang; Ye, Yumin; He, Jidong; Liu, Fu; Deng, Gang

    2018-03-01

    In the present work, we report one-step immobilization of nano-heparin coating on PLA membranes via initiated chemical vapor deposition (iCVD) for enhanced hemocompatibility. The nano-coating introduced onto the membrane surface via the crosslinking of P(MAA-EGDA) was confirmed by the FTIR, SEM and weight measurement respectively. The negative carboxyl groups could form the hydration interaction with the protein and platelets and electrostatic interaction with amide groups of thrombin by the mediation of antithrombin, which is similar but different with heparin. The P(MAA-EGDA) coated membranes showed suppressed platelet adhesion and prolonged clotting time (APTTs increased to 59 s, PTs increased to 20.4 s, TTs increased to 17.5 s, and the FIBs declined by 30 mg/dL). Moreover, the complement activation tests demonstrated the formation of C3a and C5a was inhibited. All results demonstrated that the nano-coating of P(MAA-EGDA) via iCVD significantly enhanced the hemocompatibility of PLA membranes, which is also applicable for various membranes.

  15. Sub-bandgap optical absorption spectroscopy of hydrogenated microcrystalline silicon thin films prepared using hot-wire CVD (Cat-CVD) process

    International Nuclear Information System (INIS)

    Goktas, O.; Isik, N.; Okur, S.; Gunes, M.; Carius, R.; Klomfass, J.; Finger, F.

    2006-01-01

    Hydrogenated microcrystalline silicon (μc-Si:H) thin films with different silane concentration (SC) have been prepared using the HW-CVD technique. Dual beam photoconductivity (DBP), photothermal deflection spectroscopy (PDS), and transmission measurements have been used to investigate the optical properties of the μc-Si:H films. Two different sub-bandgap absorption, α(hν), methods have been applied and analyzed to obtain a better insight into the electronic states involved. A good agreement has been obtained in the absorption spectrum obtained from the PDS and DBP measurements at energies above the bandgap. Differences between PDS and DBP spectra exist below the bandgap energy where DBP spectra always give lower α(hν) values and show a dependence on the SC. For some films, differences exist in the α(hν) spectra when the DBP measurements are carried out through the film and substrate side. In addition, for some films, there remains fringe pattern left on the spectrum after the calculation of the fringe-free absorption spectrum, which indicates structural inhomogeneities present throughout the film

  16. Synthesis of AlN fine particles by surface corona discharge-CVD; Enmen corona hoden CVD ni yoru AlN biryushi no gosei

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Y.; Chiba, S. [Hokkaido National Industrial Research Institute, Sapporo (Japan); Harima, K> ; Kondo, K.; Shinohara, K. [Hokkaido University, Sapporo (Japan)

    1994-09-15

    With an objective to improve insulating and heat dissipating substrates substituting for the conventional alumina substrates, discussions been given on synthesis of AlN fine particles by means of gaseous phase reaction between AlCl3 and NH3 using surface corona discharge as a reaction exciting source. AIN particles should be highly pure to acquire high-heat conductivity, and fine and uniform particles to obtain dense sinters at low temperatures. The particles obtained by using the present method were amorphous particles having nearly spherical form and smooth surface. The particle diameter depends on the initial concentration of AlCl3, and is proportional to 0.4 square of the concentration. Within the range in the present experiment, the diameters ranged from 208 nm to 431 nm. The particle diameter increased in proportion to 0.2 square of an average gas stagnating time within the plasma generating region. The particle size distribution consisted of highly uniform fine particles having the standard deviation at about the same degree as that in the conventional thermal CVD process. The alumina-based oxygen was removed completely by reduction due to graphite powder, but the re-oxidation during removal of the remaining graphite using combustion had oxygen remained at 7.4% by weight. 16 refs., 7 figs.

  17. Reference Gene Selection in the Desert Plant <em>Eremosparton songoricuem>m>

    Directory of Open Access Journals (Sweden)

    Dao-Yuan Zhang

    2012-06-01

    Full Text Available <em>Eremosparton songoricum em>(Litv. Vass. (<em>E. songoricumem> is a rare and extremely drought-tolerant desert plant that holds promise as a model organism for the identification of genes associated with water deficit stress. Here, we cloned and evaluated the expression of eight candidate reference genes using quantitative real-time reverse transcriptase polymerase chain reactions. The expression of these candidate reference genes was analyzed in a diverse set of 20 samples including various <em>E. songoricumem> plant tissues exposed to multiple environmental stresses. GeNorm analysis indicated that expression stability varied between the reference genes in the different experimental conditions, but the two most stable reference genes were sufficient for normalization in most conditions.<em> EsEFem> and <em>Esα-TUB> were sufficient for various stress conditions, <em>EsEF> and <em>EsACT> were suitable for samples of differing germination stages, and <em>EsGAPDH>and <em>Es>UBQ em>were most stable across multiple adult tissue samples. The <em>Es18Sem> gene was unsuitable as a reference gene in our analysis. In addition, the expression level of the drought-stress related transcription factor <em>EsDREB2em>> em>verified the utility of<em> E. songoricumem> reference genes and indicated that no single gene was adequate for normalization on its own. This is the first systematic report on the selection of reference genes in <em>E. songoricumem>, and these data will facilitate future work on gene expression in this species.

  18. Future prospect of remote Cat-CVD on the basis of the production, transportation and detection of H atoms

    International Nuclear Information System (INIS)

    Umemoto, Hironobu; Matsumura, Hideki

    2008-01-01

    The future prospect of remote Cat-CVD, in which the decomposition and the deposition chambers are separated, is discussed on the basis of the absolute density measurements of H atoms. It is now well recognized that uniform deposition is possible on a large area without plasma damages by Cat-CVD. However, we may not overlook the demerits in Cat-CVD. One of the demerits is the poisoning of the catalyzer surfaces by the material gases, both temporary and permanent. One technique to overcome this problem is remote Cat-CVD. The question is how to separate the decomposition and deposition areas. If the separation is not enough, there should be back diffusion of the material gases, which will poison the catalyzers. If the separation is too tight, radicals may not effuse out from the decomposition chamber. These problems are discussed and it is shown that SiO 2 coating to reduce the radical recombination rates on walls is promising. The possibility of the polytetrafluoroethene coating by Cat-CVD is also discussed

  19. Coffee consumption is not associated with prevalent subclinical cardiovascular disease (CVD) or the risk of CVD events, in nonalcoholic fatty liver disease: results from the multi-ethnic study of atherosclerosis.

    Science.gov (United States)

    Simon, Tracey G; Trejo, Maria Esther Perez; Zeb, Irfan; Frazier-Wood, Alexis C; McClelland, Robyn L; Chung, Raymond T; Budoff, Matthew J

    2017-10-01

    Atherosclerosis and its clinical sequelae represent the leading cause of mortality among patients with nonalcoholic fatty liver disease (NAFLD). While epidemiologic data support the hepatoprotective benefits of coffee in NAFLD, whether coffee improves NAFLD-associated CVD risk is unknown. We examined 3710 ethnically-diverse participants from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort, without history of known liver disease, and with available coffee data from a validated 120-item food frequency questionnaire. All participants underwent baseline non-contrast cardiac CT from which NAFLD was defined by liver:spleen ratio (L:S0. Major CVD events were defined by the first occurrence of myocardial infarction, cardiac arrest, angina, stroke, or CVD death. We used log-binomial regression to calculate the adjusted prevalence ratio (PR) for CAC>0 by coffee intake and NAFLD status, and events were compared between groups using frequency of events within adjusted Cox proportional hazard regression models. Seventeen percent (N=637) of participants met criteria for NAFLD. NAFLD participants were more likely to have elevated BMI (mean 31.1±5.5kg/m 2 vs. 28.0±5.2kg/m 2 , pcoffee consumption (p=0.97). Among NAFLD participants, coffee consumption was not associated with prevalent, baseline CAC>0 (PR=1.02 [0.98-1.07]). Over 12.8years of follow-up, 93 NAFLD and 415 non-NAFLD participants experienced a CV event. However, coffee intake was not associated with incident CVD events, in either NAFLD (HR=1.05 [0.91-1.21]) or non-NAFLD participants (HR=1.03 [0.97-1.11]). In a large, population-based cohort, coffee consumption was not associated with the prevalence of subclinical CVD, nor did coffee impact the future risk of major CVD events, regardless of underlying NAFLD status. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Bogani, F. [Florence Univ. (Italy). Dipt. di Energetica; Borchi, E. [Florence Univ. (Italy). Dipt. di Energetica; Bruzzi, M. [Florence Univ. (Italy). Dipt. di Energetica; Leroy, C. [Florence Univ. (Italy). Dipt. di Energetica; Sciortino, S. [Florence Univ. (Italy). Dipt. di Energetica

    1997-04-01

    The thermoluminescent (TL) response of chemical vapour deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters. (orig.).

  1. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    Science.gov (United States)

    Bogani, F.; Borchi, E.; Bruzzi, M.; Leroy, C.; Sciortino, S.

    1997-02-01

    The thermoluminescent (TL) response of Chemical Vapour Deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters.

  2. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    International Nuclear Information System (INIS)

    Bogani, F.; Borchi, E.; Bruzzi, M.; Leroy, C.; Sciortino, S.

    1997-01-01

    The thermoluminescent (TL) response of chemical vapour deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters. (orig.)

  3. Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

    International Nuclear Information System (INIS)

    Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław; Brytan, Zbigniew

    2016-01-01

    Highlights: • Prediction of the properties of PVD/CVD coatings with the use of (FEM) analysis. • Stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N coatings. • The experimental values of stresses were determined on X-ray diffraction patterns. • An FEM model was established for the purpose of building a computer simulation. - Abstract: The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were

  4. Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław, E-mail: miroslaw.bonek@polsl.pl; Brytan, Zbigniew

    2016-12-01

    Highlights: • Prediction of the properties of PVD/CVD coatings with the use of (FEM) analysis. • Stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N coatings. • The experimental values of stresses were determined on X-ray diffraction patterns. • An FEM model was established for the purpose of building a computer simulation. - Abstract: The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were

  5. Treatment with liraglutide may improve markers of CVD reflected by reduced levels of apoB

    Science.gov (United States)

    Engelbrechtsen, L.; Lundgren, J.; Wewer Albrechtsen, N. J.; Mahendran, Y.; Iepsen, E. W.; Finocchietto, P.; Jonsson, A. E.; Madsbad, S.; Holst, J. J.; Vestergaard, H.; Hansen, T.

    2017-01-01

    Summary Background Dislipidaemia and increased levels of apolipoprotein B (apoB) in individuals with obesity are risk factors for development of cardiovascular disease (CVD). The aim of this study was to investigate the effect of weight loss and weight maintenance with and without liraglutide treatment on plasma lipid profiles and apoB. Methods Fifty‐eight individuals with obesity (body mass index 34.5 ± 3.0 kg/m2 [mean ± SD]) were included in this study. After 8 weeks on a very low‐calorie diet (800 kcal/day), participants were randomized to weight maintenance with meal replacements with or without liraglutide (1.2 mg daily) for 1 year. Plasma samples from before and after weight loss and after 1 year of weight maintenance were subjected to nuclear magnetic resonance‐based lipidomics analysis. Results After an 8‐week low‐calorie diet, study participants lost 12.0 ± 2.9 kg (mean ± SD) of their body weight, which was reflected in their lipid profiles (80 out of 124 lipids changed significantly), including reduced levels of apoB, total cholesterol, free cholesterol, remnant cholesterol, triglycerides, low‐density lipoprotein and very low‐density lipoprotein subclasses. After 1 year of maintained weight loss, the majority of the lipids had returned to pre‐weight loss levels even though weight loss was successfully maintained in both groups. Interestingly, apoB levels remained low in the liraglutide treated group (apoB change: 0.03 ± 0.02 mmol/L, p = 0.4) in contrast to an increase in the control group (apoB change: 0.06 ± 0.07 mmol/L, p = 0.02). Conclusion An 8‐week low‐calorie diet, in individuals with obesity, reduced plasma levels of lipids and the atherogenic marker apoB. After 1 year of weight maintenance, only study participants treated with liraglutide maintained reduced levels of apoB, despite similar body weight maintenance. Treatment with liraglutide may therefore reduce apoB levels and thus reflect lower

  6. Treatment with liraglutide may improve markers of CVD reflected by reduced levels of apoB.

    Science.gov (United States)

    Engelbrechtsen, L; Lundgren, J; Wewer Albrechtsen, N J; Mahendran, Y; Iepsen, E W; Finocchietto, P; Jonsson, A E; Madsbad, S; Holst, J J; Vestergaard, H; Hansen, T; Torekov, S S

    2017-12-01

    Dislipidaemia and increased levels of apolipoprotein B (apoB) in individuals with obesity are risk factors for development of cardiovascular disease (CVD). The aim of this study was to investigate the effect of weight loss and weight maintenance with and without liraglutide treatment on plasma lipid profiles and apoB. Fifty-eight individuals with obesity (body mass index 34.5 ± 3.0 kg/m 2 [mean ± SD]) were included in this study. After 8 weeks on a very low-calorie diet (800 kcal/day), participants were randomized to weight maintenance with meal replacements with or without liraglutide (1.2 mg daily) for 1 year. Plasma samples from before and after weight loss and after 1 year of weight maintenance were subjected to nuclear magnetic resonance-based lipidomics analysis. After an 8-week low-calorie diet, study participants lost 12.0 ± 2.9 kg (mean ± SD) of their body weight, which was reflected in their lipid profiles (80 out of 124 lipids changed significantly), including reduced levels of apoB, total cholesterol, free cholesterol, remnant cholesterol, triglycerides, low-density lipoprotein and very low-density lipoprotein subclasses. After 1 year of maintained weight loss, the majority of the lipids had returned to pre-weight loss levels even though weight loss was successfully maintained in both groups. Interestingly, apoB levels remained low in the liraglutide treated group (apoB change: 0.03 ± 0.02 mmol/L, p = 0.4) in contrast to an increase in the control group (apoB change: 0.06 ± 0.07 mmol/L, p = 0.02). An 8-week low-calorie diet, in individuals with obesity, reduced plasma levels of lipids and the atherogenic marker apoB. After 1 year of weight maintenance, only study participants treated with liraglutide maintained reduced levels of apoB, despite similar body weight maintenance. Treatment with liraglutide may therefore reduce apoB levels and thus reflect lower CVD risk. Including apoB measurements in clinical practice when

  7. Influence of CVD diamond tips and Er:YAG laser irradiation on bonding of different adhesive systems to dentin

    OpenAIRE

    da Silva, Melissa Aline [UNESP; Nicolo, Rebeca Di [UNESP; Barcellos, Daphne Camara [UNESP; Batista, Graziela Ribeiro [UNESP; Pucci, Cesar Rogerio [UNESP; Torres, Carlos Rocha Gomes [UNESP; Borges, Alessandra Bühler [UNESP

    2013-01-01

    Aim: The aim of this study was to compare the microtensile bond strength of three adhesive systems, using different methods of dentin preparation. Materials and methods: A hundred and eight bovine teeth were used. The dentin from buccal face was exposed and prepared with three different methods, divided in 3 groups: Group 1 (DT)- diamond tip on a high-speed handpiece; Group 2 (CVD)-CVD tip on a ultrasonic handpiece; Group 3 (LA)-Er: YAG laser. The teeth were divided into 3 subgroups, accordin...

  8. Clean and polymer-free transfer of CVD-grown graphene films on hexagonal boron nitride substrates

    Science.gov (United States)

    Fujihara, Miho; Ogawa, Shun; Yoshimura, Shintaro; Inoue, Ryosuke; Maniwa, Yutaka; Taniguchi, Takashi; Watanabe, Kenji; Shinohara, Hisanori; Miyata, Yasumitsu

    2017-05-01

    This report describes the development of a solution-assisted, polymer-free transfer method and the characterization of chemical vapor deposition (CVD)-grown graphene on hexagonal boron nitride. Raman analysis reveals that polymer-free samples have small variations in G- and 2D-mode Raman frequencies and are minimally affected by charge doping as observed for clean exfoliated graphene. Electrical measurements indicate that charge doping, hysteresis, and carrier scattering are suppressed in polymer-free samples. The results demonstrate that this method provides a simple and effective way to prepare clean heterostructures of CVD-grown, large-area graphene and other two-dimensional materials.

  9. Contribution to understanding and controlling a-Si:H thin films growth by mercury-sensitised photo-CVD

    International Nuclear Information System (INIS)

    Barhdadi, A.

    2003-09-01

    Mercury-sensitized photo-CVD technique is widely used for growing amorphous silicon thin films. This attractive method allows damage-free thin film depositions at very low substrate temperatures without the deleterious effects of the other processes. This review reports on the principle and potential of this technique. It also recalls and summarizes some fundamental issues such as experimental systems or apparatus particularities, the analysis of gas-phase reactions in the reactor, the surface-reaction model of SiH 3 and H during the film growth and all the kinetic model for lamp-induced Photo-CVD. (author)

  10. Study of the triton-burnup process in different JET scenarios using neutron monitor based on CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Nemtsev, G., E-mail: g.nemtsev@iterrf.ru; Amosov, V.; Meshchaninov, S.; Rodionov, R. [Institution “Project center ITER,” Moscow (Russian Federation); Popovichev, S. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2016-11-15

    We present the results of analysis of triton burn-up process using the data from diamond detector. Neutron monitor based on CVD diamond was installed in JET torus hall close to the plasma center. We measure the part of 14 MeV neutrons in scenarios where plasma current varies in a range of 1-3 MA. In this experiment diamond neutron monitor was also able to detect strong gamma bursts produced by runaway electrons arising during the disruptions. We can conclude that CVD diamond detector will contribute to the study of fast particles confinement and help predict the disruption events in future tokamaks.

  11. Synthesis, Crystal Structure and Luminescent Property of Cd (II Complex with <em>N-Benzenesulphonyl-L>-leucine

    Directory of Open Access Journals (Sweden)

    Xishi Tai

    2012-09-01

    Full Text Available A new trinuclear Cd (II complex [Cd3(L6(2,2-bipyridine3] [L =<em> Nem>-phenylsulfonyl-L>-leucinato] has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The results show that the complex belongs to the orthorhombic, space group<em> Pem>212121 with<em> aem> = 16.877(3 Å, <em>b> em>= 22.875(5 Å, <em>c em>= 29.495(6 Å, <em>α> em>= <emem>= <emem>= 90°, <em>V> em>= 11387(4 Å3, <em>Z> em>= 4, <em>Dc>= 1.416 μg·m−3, <emem>= 0.737 mm−1, <em>F> em>(000 = 4992, and final <em>R>1 = 0.0390, <em>ωR>2 = 0.0989. The complex comprises two seven-coordinated Cd (II atoms, with a N2O5 distorted pengonal bipyramidal coordination environment and a six-coordinated Cd (II atom, with a N2O4 distorted octahedral coordination environment. The molecules form one dimensional chain structure by the interaction of bridged carboxylato groups, hydrogen bonds and p-p interaction of 2,2-bipyridine. The luminescent properties of the Cd (II complex and <em>N-Benzenesulphonyl-L>-leucine in solid and in CH3OH solution also have been investigated.

  12. OSL and TL dosimeter characterization of boron doped CVD diamond films

    Science.gov (United States)

    Gonçalves, J. A. N.; Sandonato, G. M.; Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; De la Rosa, E.; Rodríguez, R. A.; Salas, P.; Barboza-Flores, M.

    2005-04-01

    Natural diamond is an exceptional prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality CVD diamond has renewed the interest in using diamond films as radiation dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by the HFCVD method. The thermoluminescence and the optically stimulated luminescence of beta exposed diamond sample containing a B/C 4000 ppm doping presents excellent properties suitable for dosimetric applications with β-ray doses up to 3.0 kGy. The observed OSL and TL performance is reasonable appropriate to justify further investigation of diamond films as dosimeters for ionizing radiation, specially in the radiotherapy field where very well localized and in vivo and real time radiation dose applications are essential.

  13. X-ray diffraction characterization of epitaxial CVD diamond films with natural and isotopically modified compositions

    Energy Technology Data Exchange (ETDEWEB)

    Prokhorov, I. A., E-mail: igor.prokhorov@mail.ru [Russian Academy of Sciences, Space Materials Science Laboratory, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics”, Kaluga Branch (Russian Federation); Voloshin, A. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation); Ralchenko, V. G.; Bolshakov, A. P. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Romanov, D. A. [Bauman Moscow State Technical University, Kaluga Branch (Russian Federation); Khomich, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Sozontov, E. A. [National Research Centre “Kurchatov Institute” (Russian Federation)

    2016-11-15

    Comparative investigations of homoepitaxial diamond films with natural and modified isotopic compositions, grown by chemical vapor deposition (CVD) on type-Ib diamond substrates, are carried out using double-crystal X-ray diffractometry and topography. The lattice mismatch between the substrate and film is precisely measured. A decrease in the lattice constant on the order of (Δa/a){sub relax} ∼ (1.1–1.2) × 10{sup –4} is recorded in isotopically modified {sup 13}C (99.96%) films. The critical thicknesses of pseudomorphic diamond films is calculated. A significant increase in the dislocation density due to the elastic stress relaxation is revealed by X-ray topography.

  14. Spent Nuclear Fuel (SNF) Cold Vacuum Drying (CVD) Facility Operations Manual; FINAL

    International Nuclear Information System (INIS)

    IRWIN, J.J.

    1999-01-01

    This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-553, Spent Nuclear Fuel Project Final Safety Analysis Report Annex B-Cold Vacuum Drying Facility. The HNF-SD-SNF-DRD-002, 1999, Cold Vacuum Drying Facility Design Requirements, Rev. 4, and the CVDF Final Design Report. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence and references to the CVDF System Design Descriptions (SDDs). This manual has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

  15. A Bayesian method to estimate the neutron response matrix of a single crystal CVD diamond detector

    International Nuclear Information System (INIS)

    Reginatto, Marcel; Araque, Jorge Guerrero; Nolte, Ralf; Zbořil, Miroslav; Zimbal, Andreas; Gagnon-Moisan, Francis

    2015-01-01

    Detectors made from artificial chemical vapor deposition (CVD) single crystal diamond are very promising candidates for applications where high resolution neutron spectrometry in very high neutron fluxes is required, for example in fusion research. We propose a Bayesian method to estimate the neutron response function of the detector for a continuous range of neutron energies (in our case, 10 MeV ≤ E n ≤ 16 MeV) based on a few measurements with quasi-monoenergetic neutrons. This method is needed because a complete set of measurements is not available and the alternative approach of using responses based on Monte Carlo calculations is not feasible. Our approach uses Bayesian signal-background separation techniques and radial basis function interpolation methods. We present the analysis of data measured at the PTB accelerator facility PIAF. The method is quite general and it can be applied to other particle detectors with similar characteristics

  16. Study of the structural evolutions of crystalline tungsten oxide films prepared using hot-filament CVD

    International Nuclear Information System (INIS)

    Feng, P X; Wang, X P; Zhang, H X; Yang, B Q; Wang, Z B; Gonzalez-BerrIos, A; Morell, G; Weiner, B

    2007-01-01

    Structural evolutions of tungsten oxide(WO 3 ) samples on different substrates are studied using Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy. The WO 3 samples are prepared using hot-filament CVD techniques. The focus of the study is on the evolutions of nano structures at different stages following deposition time. The experimental measurements reveal evolutions of the surface structures from uniform film to fractal-like structures, and eventually to nano particles, and crystalline structures from mono (0 1 0) crystalline thin film to polycrystalline thick film developments. The effect of high temperature on the nanostructured WO 3 is also investigated. Well-aligned nanoscale WO 3 rod arrays are obtained at a substrate temperature of up to 1400 deg. C. Further increasing the substrate temperature yields microscale crystalline WO 3 particles

  17. Simulation and experimental approach to CVD-FBR aluminide coatings on ferritic steels under steam oxidation

    International Nuclear Information System (INIS)

    Leal, J.; Alcala, G.; Bolivar, F.J.; Sanchez, L.; Hierro, M.P.; Perez, F.J.

    2008-01-01

    The ferritic steels used to produce structural components for steam turbines are susceptible to strong corrosion and creep damage due to the extreme working conditions pushed to increase the process efficiency and to reduce pollutants release. The response of aluminide coatings on the P-92 ferritic steel, deposited by CVD-FBR, during oxidation in a simulated steam environment was studied. The analyses were performed at 650 deg. C in order to simulate the working conditions of a steam turbine, and 800 deg. C in order to produce a critical accelerated oxidation test. The Thermo-Calc software was used to predict the different solid phases that could be generated during the oxidation process, in both, coated and uncoated samples. In order to validate the thermodynamic results, the oxides scales produced during steam tests were characterized by different techniques such as XRD, SEM and EDS. The preliminary results obtained are discussed in the present work

  18. CVD-grown horizontally aligned single-walled carbon nanotubes: synthesis routes and growth mechanisms.

    Science.gov (United States)

    Ibrahim, Imad; Bachmatiuk, Alicja; Warner, Jamie H; Büchner, Bernd; Cuniberti, Gianaurelio; Rümmeli, Mark H

    2012-07-09

    Single-walled carbon nanotubes (SWCNTs) have attractive electrical and physical properties, which make them very promising for use in various applications. For some applications however, in particular those involving electronics, SWCNTs need to be synthesized with a high degree of control with respect to yield, length, alignment, diameter, and chirality. With this in mind, a great deal of effort is being directed to the precision control of vertically and horizontally aligned nanotubes. In this review the focus is on the latter, horizontally aligned tubes grown by chemical vapor deposition (CVD). The reader is provided with an in-depth review of the established vapor deposition orientation techniques. Detailed discussions on the characterization routes, growth parameters, and growth mechanisms are also provided. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Graphene growth on Ge(100)/Si(100) substrates by CVD method.

    Science.gov (United States)

    Pasternak, Iwona; Wesolowski, Marek; Jozwik, Iwona; Lukosius, Mindaugas; Lupina, Grzegorz; Dabrowski, Pawel; Baranowski, Jacek M; Strupinski, Wlodek

    2016-02-22

    The successful integration of graphene into microelectronic devices is strongly dependent on the availability of direct deposition processes, which can provide uniform, large area and high quality graphene on nonmetallic substrates. As of today the dominant technology is based on Si and obtaining graphene with Si is treated as the most advantageous solution. However, the formation of carbide during the growth process makes manufacturing graphene on Si wafers extremely challenging. To overcome these difficulties and reach the set goals, we proposed growth of high quality graphene layers by the CVD method on Ge(100)/Si(100) wafers. In addition, a stochastic model was applied in order to describe the graphene growth process on the Ge(100)/Si(100) substrate and to determine the direction of further processes. As a result, high quality graphene was grown, which was proved by Raman spectroscopy results, showing uniform monolayer films with FWHM of the 2D band of 32 cm(-1).

  20. Spent Nuclear Fuel (SNF) Cold Vacuum Drying (CVD) Facility Operations Manual

    Energy Technology Data Exchange (ETDEWEB)

    IRWIN, J.J.

    1999-07-02

    This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-553, Spent Nuclear Fuel Project Final Safety Analysis Report Annex B--Cold Vacuum Drying Facility. The HNF-SD-SNF-DRD-002, 1999, Cold Vacuum Drying Facility Design Requirements, Rev. 4, and the CVDF Final Design Report. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence and references to the CVDF System Design Descriptions (SDDs). This manual has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.

  1. Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual

    Energy Technology Data Exchange (ETDEWEB)

    IRWIN, J.J.

    2000-02-03

    This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of the Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the spent nuclear fuel project (SNFP) Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.

  2. Visible light irradiation-induced conductivity change for CVD-grown graphene on different substrates

    Science.gov (United States)

    Li, Xiangdi; Zhang, Peng; Liu, Xianming; Cao, Xueying; Lei, Xiaohua; Chen, Weimin

    2017-08-01

    This research examines the influence of lighting on the electrical properties of graphene on different substrates, including PET, glass and SiO2, which are the most widely used substrate materials representing the flexible and rigid applications. The graphene sheets were prepared by CVD and subsequently transferred to three substrates. The resistances of graphene under periodic visible light irradiation were measured inside a vacuum chamber. Results show that the resistances for graphene samples on all substrates increased slowly under lighting, while decreased slowly as well after the light was switched off. The change degree and speed were different for graphene on different substrates, which were influenced as well by the illumination time, environment atmosphere and irradiation power. Graphene on flexible PET substrate is more stable than that on other substrates.

  3. Size modulation of nanocrystalline silicon embedded in amorphous silicon oxide by Cat-CVD

    International Nuclear Information System (INIS)

    Matsumoto, Y.; Godavarthi, S.; Ortega, M.; Sanchez, V.; Velumani, S.; Mallick, P.S.

    2011-01-01

    Different issues related to controlling size of nanocrystalline silicon (nc-Si) embedded in hydrogenated amorphous silicon oxide (a-SiO x :H) deposited by catalytic chemical vapor deposition (Cat-CVD) have been reported. Films were deposited using tantalum (Ta) and tungsten (W) filaments and it is observed that films deposited using tantalum filament resulted in good control on the properties. The parameters which can affect the size of nc-Si domains have been studied which include hydrogen flow rate, catalyst and substrate temperatures. The deposited samples are characterized by X-ray diffraction, HRTEM and micro-Raman spectroscopy, for determining the size of the deposited nc-Si. The crystallite formation starts for Ta-catalyst around the temperature of 1700 o C.

  4. Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Milos Nesladek, Jiri J. Mares, Dominique Tromson, Christine Mer, Philippe Bergonzo, Pavel Hubik and Jozef Kristofik

    2006-01-01

    Full Text Available In this work, we report on superconductivity (SC found in thin B-doped nanocrystalline diamond films, prepared by the PE-CVD technique. The thickness of the films varies from about 100 to 400 nm, the films are grown on low-alkaline glass at substrate temperatures of about 500–700 °C. The SIMS measurements show that films can be heavily doped with boron in concentrations in the range of 3×1021 cm−3. The Raman spectra show Fano resonances, confirming the substitutional B-incorporation. The low temperature magnetotransport measurements reveal a positive magnetoresistance. The SC transition is observed at about Tc=1.66 K. A simple theory exploiting the concept of weak localization accounting for this transition is proposed.

  5. A CVD diamond detector for (n,α) cross-section measurements

    International Nuclear Information System (INIS)

    Weiss, C.

    2014-01-01

    A novel detector based on the chemical vapor deposition (CVD) diamond technology has been developed in the framework of this PhD, for the experimental determination of (n,α) cross-sections at the neutron time-of-flight facility n⎽TOF at CERN. The 59 Ni(n,α) 56 Fe cross-section, which is relevant for astrophysical questions as well as for risk-assessment studies in nuclear technology, has been measured in order to validate the applicability of the detector for such experiments. The thesis is divided in four parts. In the introductory part the motivation for measuring (n,α) cross-sections, the experimental challenges for such measurements and the reasons for choosing the CVD diamond technology for the detector are given. This is followed by the presentation of the n⎽TOF facility, an introduction to neutron-induced nuclear reactions and a brief summary of the interaction of particles with matter. The CVD diamond technology and the relevant matters related to electronics are given as well in this first part of the thesis. The second part is dedicated to the design and production of the Diamond Mosaic-Detector (DM-D) and its characterization. The 59 Ni(n,α) 56 Fe cross-section measurement at n⎽TOF and the data analysis are discussed in detail in the third part of the thesis, before the summary of the thesis and an outlook to possible future developments and applications conclude the thesis in the forth part. In this work, the Diamond Mosaic-Detector, which consist of eight single-crystal (sCVD) diamond sensors and one 'Diamond on Iridium' (DOI) sensor has proven to be well suited for (n,α) cross-section measurements for 1 MeV < E α < 22 MeV. The upper limit is given by the thickness of the sensors, d = 150 μm, while the lower limit is dictated by background induced by neutron capture reactions in in-beam materials. The cross-section measurement was focussed on the resonance integral of 59 Ni(n,α) 56 Fe at E n = 203 eV, with the aim of clarifying

  6. Synthesis and Optimization of MWCNTs on Co-Ni/MgO by Thermal CVD

    Directory of Open Access Journals (Sweden)

    H. Ryu

    2008-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs were prepared by the thermal chemical vapor deposition (CVD technique. Monometallic and bimetallic Co and Ni combinations were used as a catalyst on MgO support. The mixer of H2/C2H2 was used as a carbon source. The prepared CNTs were found to possess different shapes, morphologies, and sizes. Maximum yield was found for 50% Co (MgO: 50% and Ni: 0% catalyst at 600°C. Scanning electron microscopy (SEM and high-resolution transmission electron microscopy (HRTEM techniques were used for structural analysis. Raman spectra were taken to investigate the quality and crystalline perfection of the prepared CNTs. The ratio of D- and G-bands (ID/IG was measured from these spectra.

  7. Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual

    International Nuclear Information System (INIS)

    IRWIN, J.J.

    2000-01-01

    This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of the Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the spent nuclear fuel project (SNFP) Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

  8. Enhanced intrinsic voltage gain in artificially stacked bilayer CVD graphene field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Himadri; Kataria, Satender [RWTH Aachen University, Chair for Electronic Devices, Aachen (Germany); University of Siegen, School of Science and Technology, Siegen (Germany); Aguirre-Morales, Jorge-Daniel; Fregonese, Sebastien; Zimmer, Thomas [IMS Laboratory, Centre National de la Recherche Scientifique, University of Bordeaux, Talence (France); Passi, Vikram [University of Siegen, School of Science and Technology, Siegen (Germany); AMO GmbH, Advanced Microelectronics Center Aachen (Germany); Iannazzo, Mario; Alarcon, Eduard [Technical University of Catalonia, Department of Electronics Engineering, UPC, Barcelona (Spain); Lemme, Max C. [RWTH Aachen University, Chair for Electronic Devices, Aachen (Germany); University of Siegen, School of Science and Technology, Siegen (Germany); AMO GmbH, Advanced Microelectronics Center Aachen (Germany)

    2017-11-15

    We report on electronic transport in dual-gate, artificially stacked bilayer graphene field effect transistors (BiGFETs) fabricated from large-area chemical vapor deposited (CVD) graphene. The devices show enhanced tendency to current saturation, which leads to reduced minimum output conductance values. This results in improved intrinsic voltage gain of the devices when compared to monolayer graphene FETs. We employ a physics based compact model originally developed for Bernal stacked bilayer graphene FETs (BSBGFETs) to explore the observed phenomenon. The improvement in current saturation may be attributed to increased charge carrier density in the channel and thus reduced saturation velocity due to carrier-carrier scattering. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Structural Transformation upon Nitrogen Doping of Ultrananocrystalline Diamond Films by Microwave Plasma CVD

    Directory of Open Access Journals (Sweden)

    Chien-Chung Teng

    2009-01-01

    Full Text Available The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous and sp2/sp3 ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphous sp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films.

  10. The CVD graphene transfer procedure introduces metallic impurities which alter the graphene electrochemical properties.

    Science.gov (United States)

    Ambrosi, Adriano; Pumera, Martin

    2014-01-07

    High quality graphene films can be fabricated by chemical vapor deposition (CVD) using Ni and Cu as catalytic substrates. Such a synthesis procedure always requires a subsequent transfer process to be performed in order to eliminate the metallic substrate and transfer the graphene onto the desired surface. We show here that such a transfer process causes significant contamination of the graphene film with residual Fe and Ni metal impurities. Fe contamination derives from the use of Fe-based etching solutions to dissolve Ni (or Cu) substrates, while residual Ni (or Cu) is due to an incomplete metal substrate etching. The presence of these metallic impurities within the transferred graphene film affects tremendously its electrochemical behavior when adopted as an electrode material.

  11. Design and application of CVD diamond windows for x-rays at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Jaski, Y.; Cookson, D.

    2007-01-01

    Two types of directly cooled, 0.2-mm-thick, 8-mm-diameter clear aperture CVD diamond windows have been designed and successfully fabricated by two different vendors for use at the Advanced Photon Source (APS). Both windows contain a direct braze joint between the diamond and the cooled OFHC copper. These windows can be used to replace the front-end beryllium windows in high-heat-load applications and can be used as white beam windows in the beamlines. This paper presents the detailed design of the diamond windows, the thermal analysis of the diamond window under different thermal load configurations, as well as a complete list of the existing APS front-end beryllium window configurations and replacement scenarios. Small-angle scattering experiments have been conducted on both diamond windows and a polished beryllium window, and the results are presented.

  12. Fast method for reactor and feature scale coupling in ALD and CVD

    Science.gov (United States)

    Yanguas-Gil, Angel; Elam, Jeffrey W.

    2017-08-08

    Transport and surface chemistry of certain deposition techniques is modeled. Methods provide a model of the transport inside nanostructures as a single-particle discrete Markov chain process. This approach decouples the complexity of the surface chemistry from the transport model, thus allowing its application under general surface chemistry conditions, including atomic layer deposition (ALD) and chemical vapor deposition (CVD). Methods provide for determination of determine statistical information of the trajectory of individual molecules, such as the average interaction time or the number of wall collisions for molecules entering the nanostructures as well as to track the relative contributions to thin-film growth of different independent reaction pathways at each point of the feature.

  13. Aluminum and aluminum/silicon coatings on ferritic steels by CVD-FBR technology

    International Nuclear Information System (INIS)

    Perez, F.J.; Hierro, M.P.; Trilleros, J.A.; Carpintero, M.C.; Sanchez, L.; Bolivar, F.J.

    2006-01-01

    The use of chemical vapor deposition by fluidized bed reactors (CVD-FBR) offers some advantages in comparison to other coating techniques such as pack cementation, because it allows coating deposition at lower temperatures than pack cementation and at atmospheric pressure without affecting the mechanical properties of material due to heat treatments of the bulk during coating process. Aluminum and aluminum/silicon coatings have been obtained on two different ferritics steels (P-91 and P-92). The coatings were analyzed using several techniques like SEM/EDX and XRD. The results indicated that both coatings were form by Fe 2 Al 5 intermetallic compound, and in the co-deposition the Si was incorporated to the Fe 2 Al 5 structure in small amounts

  14. Ion beam induced charge and cathodoluminescence imaging of response uniformity of CVD diamond radiation detectors

    CERN Document Server

    Sellin, P J; Galbiati, A; Maghrabi, M; Townsend, P D

    2002-01-01

    The uniformity of response of CVD diamond radiation detectors produced from high quality diamond film, with crystallite dimensions of >100 mu m, has been studied using ion beam induced charge imaging. A micron-resolution scanning alpha particle beam was used to produce maps of pulse height response across the device. The detectors were fabricated with a single-sided coplanar electrode geometry to maximise their sensitivity to the surface region of the diamond film where the diamond crystallites are highly ordered. High resolution ion beam induced charge images of single crystallites were acquired that demonstrate variations in intra-crystallite charge transport and the termination of charge transport at the crystallite boundaries. Cathodoluminescence imaging of the same crystallites shows an inverse correlation between the density of radiative centres and regions of good charge transport.

  15. The CVD ZrB2 as a selective solar absorber

    Science.gov (United States)

    Randich, E.; Allred, D. D.

    Coatings of ZrB2 and TiB2 for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB2 and 800 K for Z4B2. Both materials exhibit innate spectral selectivity with emittance at 375 K ranging from 0.06 to 0.09 and solar absorptance for ZrB2 ranging from 0.67 to 0.77 and solar absorptance for TiB2 ranging from 0.46 to 0.58. ZrB2 has better solar selectivity and more desirable oxidation behavior than TiB2. A 0.071 micrometer antireflection coating of Si3N4 deposited on the ZrB2 coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged.

  16. Development of laser-fired contacts for amorphous silicon layers obtained by Hot-Wire CVD

    International Nuclear Information System (INIS)

    Munoz, D.; Voz, C.; Blanque, S.; Ibarz, D.; Bertomeu, J.; Alcubilla, R.

    2009-01-01

    In this work we study aluminium laser-fired contacts for intrinsic amorphous silicon layers deposited by Hot-Wire CVD. This structure could be used as an alternative low temperature back contact for rear passivated heterojunction solar cells. An infrared Nd:YAG laser (1064 nm) has been used to locally fire the aluminium through the thin amorphous silicon layers. Under optimized laser firing parameters, very low specific contact resistances (ρ c ∼ 10 mΩ cm 2 ) have been obtained on 2.8 Ω cm p-type c-Si wafers. This investigation focuses on maintaining the passivation quality of the interface without an excessive increase in the series resistance of the device.

  17. Photodecomposition of Hg - Photo - CVD monosilane. Application to hydrogenated amorphous silicon thin films

    International Nuclear Information System (INIS)

    Aka, B.

    1989-04-01

    The construction of a Hg-photo-CVD device is discussed. The system enables the manufacturing of hydrogenous thin films of amorphous silicon from monosilane compound. The reaction mechanisms taking place in the gaseous phase and at the surface, and the optimal conditions for the amorphous silicon film growth are studied. The analysis technique is based on the measurement of the difference between the condensation points of the gaseous components of the mixture obtained from the monosilane photolysis. A kinetic simplified model is proposed. Conductivity measurements are performed and the heat treatment effects are analyzed. Trace amounts of oxygen and carbon are found in the material. No Hg traces are detected by SIMS analysis [fr

  18. Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

    Science.gov (United States)

    Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław; Brytan, Zbigniew

    2016-12-01

    The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were recorded during the modelling process.

  19. CVD growth of graphene under exfoliated hexagonal boron nitride for vertical hybrid structures

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Min [SKKU Advanced Institute of Nanotechnology (SAINT) (Korea, Republic of); Center for Human Interface Nanotechnology (HINT) (Korea, Republic of); Jang, Sung Kyu [SKKU Advanced Institute of Nanotechnology (SAINT) (Korea, Republic of); Song, Young Jae [SKKU Advanced Institute of Nanotechnology (SAINT) (Korea, Republic of); Department of Physics, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Lee, Sungjoo, E-mail: leesj@skku.edu [SKKU Advanced Institute of Nanotechnology (SAINT) (Korea, Republic of); Center for Human Interface Nanotechnology (HINT) (Korea, Republic of); College of Information and Communication Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of)

    2015-01-15

    Graphical abstract: We have demonstrated a novel yet simple method for fabricating graphene-based vertical hybrid structures by performing the CVD growth of graphene at an h-BN/Cu interface. Our systematic Raman measurements combined with plasma etching process indicate that a graphene film is grown under exfoliated h-BN rather than on its top surface, and that an h-BN/graphene vertical hybrid structure has been fabricated. Electrical transport measurements of this h-BN/graphene, transferred on SiO2, show the carrier mobility up to approximately 2250 cm{sup 2} V{sup −1} s{sup −1}. The developed method would enable the exploration of the possibility of novel hybrid structure integration with two-dimensional material systems. - Abstract: We have demonstrated a novel yet simple method for fabricating graphene-based vertical hybrid structures by performing the CVD growth of graphene at an h-BN/Cu interface. Our systematic Raman measurements combined with plasma etching process indicate that a graphene film is grown under exfoliated h-BN rather than on its top surface, and that an h-BN/graphene vertical hybrid structure has been fabricated. Electrical transport measurements of this h-BN/graphene, transferred on SiO{sub 2}, show the carrier mobility up to approximately 2250 cm{sup 2} V{sup −1} s{sup −1}. The developed method would enable the exploration of the possibility of novel hybrid structure integration with two-dimensional material systems.

  20. Pushing the boundaries of high power lasers: low loss, large area CVD diamond

    Science.gov (United States)

    Wickham, Benjamin; Schoofs, Frank; Olsson-Robbie, Stefan; Bennett, Andrew; Balmer, Richard

    2018-02-01

    Synthetic CVD diamond has exceptional properties, including broad spectral transmission, physical and chemical robustness, and the highest thermal conductivity of any known material, making diamond an attractive material for medium to high power optical and laser applications, minimizing the detrimental effects of thermal lensing and radiation damage. Example applications include ATR prisms, Raman laser crystals, extra- and intra-cavity laser cooling. In each case the demands on the fundamental material properties and fabrication routes are slightly different. In recent years, there has been good progress in the development of low-loss, single crystal diamond, suitable for higher power densities, higher pulse rates and more demanding intra- and extra-cavity thermal management. The adoption of single crystal diamond in this area has however, been hindered by the availability of large area, low birefringence plates. To address this, we report a combination of CVD growth and processing methods that have enabled the manufacture of large, low defect substrates. A final homoepitaxial, low absorption synthesis stage has produced plates with large area (up to 16 mm edge length), low absorption (α<0.005 cm-1 at 1064 nm), and low birefringence (Δn <10-5), suitable for double-sided intra-cavity cooling. We demonstrate the practical advances in synthesis, including increasing the size while reducing in-use losses compared to previous generations of single crystal material, and practical developments in processing and implementation of the single crystal diamond parts, optimizing them for use in a state-of-the-art femto-second pulsed Ti:Sa thin disk gain module, all made in collaboration with the wider European FP7 funded Ti:Sa TD consortium.

  1. SU-E-T-153: Detector-Grade CVD Diamond for Radiotherapy Dosimetry.

    Science.gov (United States)

    Lansley, S; Betzel, G; McKay, D; Meyer, J

    2012-06-01

    To evaluate the use of commercially available detector-grade synthetic diamond films made via chemical vapor deposition (CVD) as x- ray detectors for radiotherapy dosimetry. A detector was fabricated using high-quality single crystal CVD diamond films (0.5 × 3 × 3 mm̂3) with 0.4 mm̂3 sensitive volumes, which were encapsulated with PMMA. The detector was placed in a (30 × 30 × 30 cm̂3) PTW water phantom. Six- and ten-MV photons from an Elekta Synergy linac were measured using an SSD of 90 cm and typically a 10-cm phantom depth with a 10 × 10 cm̂2 field size in the central axis of the beam. Data acquisition was performed using a PTW UNIDOS E electrometer with a 100-V bias. The detector was evaluated by measuring leakage current, priming dose, response dynamics, dose linearity, dependence on dose rate, percent depth dose (6 and 10 MV photons) and output factors. Some measurements were compared with a Si diode detector, 0.04 and/or 0.13-cc ion chamber(s). Leakage currents were negligible (∼1 pA) given the overall average sensitivity of the material (680 nC/Gy at 100 V). Detector current rise and fall times were detectors as expected. The type of diamond tested has potential to be used for small field dosimetry due to its small sensitive volume and high sensitivity. Further experiments are ongoing and detector packaging is yet to be optimized. © 2012 American Association of Physicists in Medicine.

  2. Charge transfer effects, thermo and photochromism in single crystal CVD synthetic diamond.

    Science.gov (United States)

    Khan, R U A; Martineau, P M; Cann, B L; Newton, M E; Twitchen, D J

    2009-09-09

    We report on the effects of thermal treatment and ultraviolet irradiation on the point defect concentrations and optical absorption profiles of single crystal CVD synthetic diamond. All thermal treatments were below 850 K, which is lower than the growth temperature and unlikely to result in any structural change. UV-visible absorption spectroscopy measurements showed that upon thermal treatment (823 K), various broad absorption features diminished: an absorption band at 270 nm (used to deduce neutral single substitutional nitrogen (N(S)(0)) concentrations) and also two broad features centred at approximately 360 and 520 nm. Point defect centre concentrations as a function of temperature were also deduced using electron paramagnetic resonance (EPR) spectroscopy. Above ∼500 K, we observed a decrease in the concentration of N(S)(0) centres and a concomitant increase in the negatively charged nitrogen-vacancy-hydrogen (NVH) complex (NVH(-)) concentration. Both transitions exhibited an activation energy between 0.6 and 1.2 eV, which is lower than that for the N(S)(0) donor (∼1.7 eV). Finally, it was found that illuminating samples with intense short-wave ultraviolet light recovered the N(S)(0) concentration and also the 270, 360 and 520 nm absorption features. From these results, we postulate a valence band mediated charge transfer process between NVH and single nitrogen centres with an acceptor trap depth for NVH of 0.6-1.2 eV. Because the loss of N(S)(0) concentration is greater than the increase in NVH(-) concentration we also suggest the presence of another unknown acceptor existing at a similar energy to NVH. The extent to which the colour in CVD synthetic diamond is dependent on prior history is discussed.

  3. Silicon Oil DC200(R)5CST as AN Alternative Coolant for Cvd Diamond Windows

    Science.gov (United States)

    Vaccaro, A.; Aiello, G.; Meier, A.; Schere, T.; Schreck, S.; Spaeh, P.; Strauss, D.; Gantenbein, G.

    2011-02-01

    The production of high power mm-wave radiation is a key technology in large fusion devices, since it is required for localized plasma heating and current drive. Transmission windows are necessary to keep the vacuum in the gyrotron system and also act as tritium barriers. With its excellent optical, thermal and mechanical properties, synthetic CVD (Chemical Vapor Deposition) diamond is the state of the art material for the cw transmission of the mm-wave beams produced by high power gyrotrons. The gyrotrons foreseen for the W7-X stellarator are designed for cw operation with 1 MW output power at 140 GHz. The output window unit is designed by TED (Thales Electron Devices, France) using a single edge circumferentially cooled CVD-diamond disc with an aperture of 88 mm. The window unit is cooled by de-ionized water which is considered as chemical aggressive and might cause corrosion in particular at the brazing. The use of a different coolant such as silicon oil could prevent this issue. The cooling circuit has been simulated by steady-state CFD analysis. A total power generation of 1 kW (RF transmission losses) with pure Gaussian distribution has been assumed for the diamond disc. The performance of both water and the industrial silicon oil DC200(R) have been investigated and compared with a focus on the temperature distribution on the disc, the pressure drop across the cooling path and the heat flux distribution. Although the silicon oil has a higher viscosity (~x5), lower heat capacity (~x1/2) and lower thermal conductivity (~x1/3), it has proven to be a good candidate as alternative to water.

  4. CVD-associated non-coding RNA, ANRIL, modulates expression of atherogenic pathways in VSMC

    International Nuclear Information System (INIS)

    Congrains, Ada; Kamide, Kei; Katsuya, Tomohiro; Yasuda, Osamu; Oguro, Ryousuke; Yamamoto, Koichi; Ohishi, Mitsuru; Rakugi, Hiromi

    2012-01-01

    Highlights: ► ANRIL maps in the strongest susceptibility locus for cardiovascular disease. ► Silencing of ANRIL leads to altered expression of tissue remodeling-related genes. ► The effects of ANRIL on gene expression are splicing variant specific. ► ANRIL affects progression of cardiovascular disease by regulating proliferation and apoptosis pathways. -- Abstract: ANRIL is a newly discovered non-coding RNA lying on the strongest genetic susceptibility locus for cardiovascular disease (CVD) in the chromosome 9p21 region. Genome-wide association studies have been linking polymorphisms in this locus with CVD and several other major diseases such as diabetes and cancer. The role of this non-coding RNA in atherosclerosis progression is still poorly understood. In this study, we investigated the implication of ANRIL in the modulation of gene sets directly involved in atherosclerosis. We designed and tested siRNA sequences to selectively target two exons (exon 1 and exon 19) of the transcript and successfully knocked down expression of ANRIL in human aortic vascular smooth muscle cells (HuAoVSMC). We used a pathway-focused RT-PCR array to profile gene expression changes caused by ANRIL knock down. Notably, the genes affected by each of the siRNAs were different, suggesting that different splicing variants of ANRIL might have distinct roles in cell physiology. Our results suggest that ANRIL splicing variants play a role in coordinating tissue remodeling, by modulating the expression of genes involved in cell proliferation, apoptosis, extra-cellular matrix remodeling and inflammatory response to finally impact in the risk of cardiovascular disease and other pathologies.

  5. Buckwheat and CVD Risk Markers: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Liangkui Li

    2018-05-01

    Full Text Available The effects of buckwheat intake on cardiovascular diseases (CVDs have not been systematically investigated. The aim of the present study was to comprehensively summarize studies in humans and animals, evaluating the impact of buckwheat consumption on CVD risk markers and to conduct a meta-analysis of relevant data. Thirteen randomized, controlled human studies, two cross-sectional human studies and twenty-one animal studies were identified. Using random-effects models, the weighted mean difference of post-intervention concentrations of blood glucose, total cholesterol and triglycerides were significantly decreased following buckwheat intervention compared with controls [differences in blood glucose: −0.85 mmol/L (95% CI: −1.31, −0.39, total cholesterol: 0.50 mmol/L (95% CI: −0.80, −0.20 and triglycerides: 0.25 mmol/L (95% CI: −0.49, −0.02]. Responses of a similar magnitude were seen in two cross-sectional studies. For animal studies, nineteen of twenty-one studies showed a significant reduction in total cholesterol of between 12% and 54%, and fourteen of twenty studies showed a significant reduction in triglycerides of between 2% and 74%. All exhibited high unexplained heterogeneity. There was inconsistency in HDL cholesterol outcomes in both human and animal studies. It remains unclear whether increased buckwheat intake significantly benefits other markers of CVD risk, such as weight, blood pressure, insulin, and LDL-cholesterol, and underlying mechanisms responsible for any effects are unclear.

  6. Structural and optical properties of CdO nanostructures prepared by atmospheric-pressure CVD

    International Nuclear Information System (INIS)

    Terasako, T.; Fujiwara, T.; Nakata, Y.; Yagi, M.; Shirakata, S.

    2013-01-01

    Cadmium oxide (CdO) nanostructures of various shapes were successfully grown on gold (Au) nanocolloid coated c-plane sapphire substrates by atmospheric-pressure CVD using Cd powder and H 2 O as source materials. CdO nanorods (NRs) exhibited tapered shapes and the degree of the tapering became larger with increasing substrate temperature. One of the possible reasons for the tapering behavior is the competition between the axial growth due to the vapor–liquid–solid (VLS) mechanism and the radial growth due to the vapor–solid (VS) mechanism. The influence of the competition between the two different growth mechanisms was also confirmed on the appearance of “seaweed-like” NRs. Moreover, we cannot neglect the influence of the shrinkage of catalyst particles during the growth process on the tapering behavior. In addition, there is a possibility that the temporal evolution of catalyst particles, such as diffusion, splitting, migration and coalescence, contributes not only to the disappearance of catalyst particles on the tips of the NRs, resulting in the enhancement of the radial growth relative to the axial growth, but also to the formation of nanobelts (NBs) and nanotrees (NTs). Photoacoustic measurements revealed that the absorption edge shifts towards lower energies and the absorption band below the absorption edge becomes larger with increasing T S . This tendency may be due to the increase of intrinsic defects and/or the decrease in residual impurities. - Highlights: ► Various shapes of CdO nanostructures were grown by AP-CVD using Cd and H 2 O. ► This diversity is due to the competition between VLS and VS mechanisms. ► The temporal evolution of Au catalyst particles also contributes to the diversity. ► Photoacoustic spectra were changed, depending on the substrate temperature. ► This is probably related to the intrinsic defects and/or residual impurities

  7. CVD-associated non-coding RNA, ANRIL, modulates expression of atherogenic pathways in VSMC

    Energy Technology Data Exchange (ETDEWEB)

    Congrains, Ada; Kamide, Kei [Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine (Japan); Katsuya, Tomohiro [Clinical Gene Therapy, Osaka University Graduate School of Medicine (Japan); Yasuda, Osamu [Department of Cardiovascular Clinical and Translational Research, Kumamoto University Hospital (Japan); Oguro, Ryousuke; Yamamoto, Koichi [Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine (Japan); Ohishi, Mitsuru, E-mail: ohishi@geriat.med.osaka-u.ac.jp [Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine (Japan); Rakugi, Hiromi [Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine (Japan)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer ANRIL maps in the strongest susceptibility locus for cardiovascular disease. Black-Right-Pointing-Pointer Silencing of ANRIL leads to altered expression of tissue remodeling-related genes. Black-Right-Pointing-Pointer The effects of ANRIL on gene expression are splicing variant specific. Black-Right-Pointing-Pointer ANRIL affects progression of cardiovascular disease by regulating proliferation and apoptosis pathways. -- Abstract: ANRIL is a newly discovered non-coding RNA lying on the strongest genetic susceptibility locus for cardiovascular disease (CVD) in the chromosome 9p21 region. Genome-wide association studies have been linking polymorphisms in this locus with CVD and several other major diseases such as diabetes and cancer. The role of this non-coding RNA in atherosclerosis progression is still poorly understood. In this study, we investigated the implication of ANRIL in the modulation of gene sets directly involved in atherosclerosis. We designed and tested siRNA sequences to selectively target two exons (exon 1 and exon 19) of the transcript and successfully knocked down expression of ANRIL in human aortic vascular smooth muscle cells (HuAoVSMC). We used a pathway-focused RT-PCR array to profile gene expression changes caused by ANRIL knock down. Notably, the genes affected by each of the siRNAs were different, suggesting that different splicing variants of ANRIL might have distinct roles in cell physiology. Our results suggest that ANRIL splicing variants play a role in coordinating tissue remodeling, by modulating the expression of genes involved in cell proliferation, apoptosis, extra-cellular matrix remodeling and inflammatory response to finally impact in the risk of cardiovascular disease and other pathologies.

  8. Surface modification on 304 SS by plasma-immersed ion implantation to improve the adherence of a CVD diamond film

    Energy Technology Data Exchange (ETDEWEB)

    Nono, M.C.A.; Corat, E.J. (Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos, SP (Brazil)); Ueda, M.; Stellati, C.; Barroso, J.J.; Conrad, J.R.; Shamim, M.; Fetherston, P.; Sridharan, K.

    1999-02-01

    The weak adherence of chemical vapor deposited (CVD) diamond films on steel substrates is an important factor that limits the technological applications of these materials. We are interested in enhancing the film-to-substrate adherence by using substrate surfaces with a previous modification by plasma-immersed ion implantation (PIII). In this work we present and discuss the preliminary results on phase formation, microstructure and adherence evaluations. CVD diamond films were deposited on 304 SS, the surface of which was modified by implanted carbon ions. The samples were first submitted to implantation with 30 keV carbon ions at different doses. Later, these surfaces were examined by Auger spectroscopy (SAM), scanning electron microscopy (SEM) and X-ray diffraction. We observed a metastable carbide phase formed from carbon and iron, which is considered to be a good polycrystalline material for the nucleation of CVD diamond crystals. The CVD diamond nucleation and film growth were observed by SEM and Raman spectroscopy. These results are discussed with the emphasis on the carbon diffusion barrier on the substrate surfaces. The preliminary results of diamond growth were encouraging. (orig.) 7 refs.

  9. Effect of mixture ratios and nitrogen carrier gas flow rates on the morphology of carbon nanotube structures grown by CVD

    CSIR Research Space (South Africa)

    Malgas, GF

    2008-02-01

    Full Text Available This paper reports on the growth of carbon nanotubes (CNTs) by thermal Chemical Vapour Deposition (CVD) and investigates the effects of nitrogen carrier gas flow rates and mixture ratios on the morphology of CNTs on a silicon substrate by vaporizing...

  10. Influence of CVD diamond tips and Er:YAG laser irradiation on bonding of different adhesive systems to dentin.

    Science.gov (United States)

    da Silva, Melissa Aline; Di Nicolo, Rebeca; Barcellos, Daphne Camara; Batista, Graziela Ribeiro; Pucci, Cesar Rogerio; Rocha Gomes Torres, Carlos; Borges, Alessandra Bühler

    2013-01-01

    The aim of this study was to compare the microtensile bond strength of three adhesive systems, using different methods of dentin preparation. A hundred and eight bovine teeth were used. The dentin from buccal face was exposed and prepared with three different methods, divided in 3 groups: Group 1 (DT)- diamond tip on a high-speed handpiece; Group 2 (CVD)-CVD tip on a ultrasonic handpiece; Group 3 (LA)-Er: YAG laser. The teeth were divided into 3 subgroups, according adhesive systems used: Subgroup 1-Adper Single Bond Plus/3M ESPE (SB) total-etch adhesive; Subgroup 2-Adper Scotchbond SE/3M ESPE (AS) selfetching adhesive; Subgroup 3-Clearfil SE Bond/Kuraray (CS) selfetching adhesive. Blocks of composite (Filtek Z250-3M ESPE) 4 mm high were built up and specimens were stored in deionized water for 24 hours at 37°C. Serial mesiodistal and buccolingual cuts were made and stick-like specimens were obtained, with transversal section of 1.0 mm(2). The samples were submitted to microtensile test at 1 mm/min and load of 10 kg in a universal testing machine. Data (MPa) were subjected to ANOVA and Tukey's tests (p adhesive produced significantly lower bond strength values compared to other groups. Surface treatment with Er: YAG laser associated with Single Bond Plus or Clearfil SE Bond adhesives and surface treatment with CVD tip associated with Adper Scotchbond SE adhesive produced significantly lower bond strength values compared to surface treatment with diamond or CVD tips associated with Single Bond Plus or Adper Scotchbond SE adhesives. Interactions between laser and the CVD tip technologies and the different adhesive systems can produce a satisfactory bonding strength result, so that these associations may be beneficial and enhance the clinical outcomes.

  11. Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

    Institute of Scientific and Technical Information of China (English)

    Zhuji Jin; Zewei Yuan; Renke Kang; Boxian Dong

    2009-01-01

    Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

  12. Effect of PbI2 deposition rate on two-step PVD/CVD all-vacuum prepared perovskite

    International Nuclear Information System (INIS)

    Ioakeimidis, Apostolos; Christodoulou, Christos; Lux-Steiner, Martha; Fostiropoulos, Konstantinos

    2016-01-01

    In this work we fabricate all-vacuum processed methyl ammonium lead halide perovskite by a sequence of physical vapour deposition of PbI 2 and chemical vapour deposition (CVD) of CH 3 NH 3 I under a static atmosphere. We demonstrate that for higher deposition rate the (001) planes of PbI 2 film show a higher degree of alignment parallel to the sample's surface. From X-ray diffraction data of the resulted perovskite film we derive that the intercalation rate of CH 3 NH 3 I is fostered for PbI 2 films with higher degree of (001) planes alignment. The stoichiometry of the produced perovskite film is also studied by Hard X-ray photoelectron spectroscopy measurements. Complete all-vacuum perovskite solar cells were fabricated on glass/ITO substrates coated by an ultra-thin (5 nm) Zn-phthalocyanine film as hole selective layer. A dependence of residual PbI 2 on the solar cells performance is displayed, while photovoltaic devices with efficiency up to η=11.6% were achieved. - Graphical abstract: A two-step PVD/CVD processed perovskite film with the CVD intercalation rate of CH 3 NCH 3 molecules been fostered by increasing the PVD rate of PbI 2 and prolonging the CVD time. - Highlights: • A simple PVD/CVD process for perovskite film production. • Increased PVD rate yields better alignment of the PbI 2 (001) crystallite planes. • CH 3 NH 3 I intercalation process fostered by increased PbI 2 PVD rate. • Stoichiometric CH 3 NH 3 PbI 3 suitable as absorber in photovoltaic applications • Reduced PbI 2 residue at the bottom of CH 3 NH 3 PbI 3 improves device performance.

  13. Optimization of a Wcl6 CVD System to Coat UO2 Powder with Tungsten

    Science.gov (United States)

    Belancik, Grace A.; Barnes, Marvin W.; Mireles, Omar; Hickman, Robert

    2015-01-01

    In order to achieve deep space exploration via Nuclear Thermal Propulsion (NTP), Marshall Space Flight Center (MSFC) is developing W-UO2 CERMET fuel elements, with focus on fabrication, testing, and process optimization. A risk of fuel loss is present due to the CTE mismatch between tungsten and UO2 in the W-60vol%UO2 fuel element, leading to high thermal stresses. This fuel loss can be reduced by coating the spherical UO2 particles with tungsten via H2/WCl6 reduction in a fluidized bed CVD system. Since the latest incarnation of the inverted reactor was completed, various minor modifications to the system design were completed, including an inverted frit sublimer. In order to optimize the parameters to achieve the desired tungsten coating thickness, a number of trials using surrogate HfO2 powder were performed. The furnace temperature was varied between 930 C and 1000degC, and the sublimer temperature was varied between 140 C and 200 C. Each trial lasted 73-82 minutes, with one lasting 205 minutes. A total of 13 trials were performed over the course of three months, two of which were re-coatings of previous trials. The powder samples were weighed before and after coating to roughly determine mass gain, and Scanning Electron Microscope (SEM) data was also obtained. Initial mass results indicated that the rate of layer deposition was lower than desired in all of the trials. SEM confirmed that while a uniform coating was obtained, the average coating thickness was 9.1% of the goal. The two re-coating trials did increase the thickness of the tungsten layer, but only to an average 14.3% of the goal. Therefore, the number of CVD runs required to fully coat one batch of material with the current configuration is not feasible for high production rates. Therefore, the system will be modified to operate with a negative pressure environment. This will allow for better gas mixing and more efficient heating of the substrate material, yielding greater tungsten coating per trial.

  14. Efecto del argon en películas CNxHy depositadas mediante ECR-CVD

    Directory of Open Access Journals (Sweden)

    Albella, J. M.

    2004-04-01

    Full Text Available Carbon nitride films have been deposited by ECR-CVD, from Ar/CH4/N2 gas mixtures with different methane concentrations. Infrared Spectroscopy (IRS and Elastic Recoil Detection Analysis (ERDA have been used for films characterisation and Optical Emission Spectroscopy (OES for plasma analysis. Argon concentration in the gas mixture controls the growth rate as well as the composition of the film. In the proposed model, argon plays a key role in the activation of methane molecules. Also, during the growth of the film, two processes may be considered: i Film formation and ii Etching of the growing surface. Changing the gas mixture composition affects both processes, which results in films with different composition and structure as well as different deposition rates.Se ha estudiado el efecto del argon durante el proceso de CVD asistido por un plasma ECR para la síntesis de películas de nitruro de carbono (CNxHy a partir de mezclas gaseosas Ar/CH4/N2 con diferente contenido de metano. Las películas depositadas han sido analizadas mediante espectroscopía infrarroja (IRS y ERDA (Elastic Recoil Detection Analysis, y el análisis del plasma ha sido realizado utilizando la técnica de espectroscopía de emisión óptica (OES. La velocidad de deposición y la composición de las películas depositadas se encuentran determinadas por la concentración de argon en la mezcla gaseosa. Se propone un modelo, según el cual el argon juega un papel fundamental como activador de las moléculas de metano. El modelo propuesto incluye dos procesos simultáneos durante el crecimiento de las capas : i formación de la capa y ii ataque de la superficie de crecimiento. Según la composición de la mezcla gaseosa se favorece uno u otro proceso, lo que conduce a velocidades de deposición diferentes así como a depósitos con diferente composición y estructura atómica.

  15. CVD-MPFA full pressure support, coupled unstructured discrete fracture-matrix Darcy-flux approximations

    Science.gov (United States)

    Ahmed, Raheel; Edwards, Michael G.; Lamine, Sadok; Huisman, Bastiaan A. H.; Pal, Mayur

    2017-11-01

    Two novel control-volume methods are presented for flow in fractured media, and involve coupling the control-volume distributed multi-point flux approximation (CVD-MPFA) constructed with full pressure support (FPS), to two types of discrete fracture-matrix approximation for simulation on unstructured grids; (i) involving hybrid grids and (ii) a lower dimensional fracture model. Flow is governed by Darcy's law together with mass conservation both in the matrix and the fractures, where large discontinuities in permeability tensors can occur. Finite-volume FPS schemes are more robust than the earlier CVD-MPFA triangular pressure support (TPS) schemes for problems involving highly anisotropic homogeneous and heterogeneous full-tensor permeability fields. We use a cell-centred hybrid-grid method, where fractures are modelled by lower-dimensional interfaces between matrix cells in the physical mesh but expanded to equi-dimensional cells in the computational domain. We present a simple procedure to form a consistent hybrid-grid locally for a dual-cell. We also propose a novel hybrid-grid for intersecting fractures, for the FPS method, which reduces the condition number of the global linear system and leads to larger time steps for tracer transport. The transport equation for tracer flow is coupled with the pressure equation and provides flow parameter assessment of the fracture models. Transport results obtained via TPS and FPS hybrid-grid formulations are compared with the corresponding results of fine-scale explicit equi-dimensional formulations. The results show that the hybrid-grid FPS method applies to general full-tensor fields and provides improved robust approximations compared to the hybrid-grid TPS method for fractured domains, for both weakly anisotropic permeability fields and very strong anisotropic full-tensor permeability fields where the TPS scheme exhibits spurious oscillations. The hybrid-grid FPS formulation is extended to compressible flow and the

  16. Synthesis and characterization of hafnium carbide microcrystal chains with a carbon-rich shell via CVD

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Liu, Sen; Fu, Yangxi; Li, Yixian; Qiang, Xinfa

    2013-01-01

    Graphical abstract: Novel HfC microcrystal chains have been synthesized via a catalyst-assisted chemical vapor deposition process. SEM results show the chains have a periodically changing diameter and a nanoscale sharpening tip. Analysis of TEM/SAED/EELS/EDX data shows the single-crystal chains grow along a [0 0 1] direction and consist of a HfC core and a thin carbon-rich shell with embedded HfC nanocrystallites surrounding the core. This work achieves the controllable preparation of nanoscale HfC sharpening tips for application as a point electron emission source and facilitates the application of HfC ultrafast laser-triggered tips in attosecond science. Highlights: •HfC microcrystal chains were synthesized by a catalyst-assisted CVD. •The chains grow along a [0 0 1] direction and have a periodically changing diameter. •Single-crystal HfC core is sheathed by a thin carbon-rich shell. •A growth mechanism model is proposed to explain the growth of microcrystal chians. •This work achieves the controllable preparation of nanoscale HfC sharpening tips. -- Abstract: Novel hafnium carbide (HfC) microcrystal chains, with a periodically changing diameter and a nanoscale sharpening tip at the chain end, have been synthesized via a catalyst-assisted chemical vapor deposition (CVD) process. The as-synthesized chains with many octahedral microcrystals have diameters of between several hundreds of nm and 6 μm and lengths of ∼500 μm. TEM diffraction studies show that the chains are single-crystalline HfC and preferentially grow along a [0 0 1] crystal orientation. TEM/EELS/EDX analysis proves the chains are composed of a HfC core and a thin (several tens of nm to 100 nm) carbon-rich shell with the embedded HfC nanocrystallites (typically below 10 nm) surrounding the core. The growth mechanism model for the chains based on the vapor–liquid–solid process, the vapor–solid process, and the HfC crystal growth characteristics is discussed

  17. Study on the low leakage current of an MIS structure fabricated by ICP-CVD

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, S-Y; Hon, M-H [Department of Materials Science and Engineering, National Cheng Kung University, 1, Ta-Hsueh Road, Tainan, 701 Taiwan (China); Lu, Y-M, E-mail: ymlumit@yahoo.com.tw

    2008-03-15

    As the dimensions of electric devices continue to shrink, it is becoming increasingly important to understand how to obtain good quality gate oxide film materials wilth higher carrier mobility, lower leakage current and greater reliability. All of them have become major concerns in the fabrication of thin film oxide transistors. A novel film deposition method called Inductively Coupled Plasma-Chemical Vapor Deposition (ICP-CVD) has received attraction in the semiconductor industry, because it can be capable of generating high density plasmas at extremely low temperature, resulting in less ion bombardment of the material surface. In this work, we present the results of crystallized silicon dioxide films deposited by inductively coupled plasma chemical vapor deposition technique at an extremely low temperature of 90 deg. C. The value of the refractive index of the crystallized ICP-CVD SiO{sub 2} film depends on the r.f. power of the ICP system, and approximates to be 1.46. This value is comparable to that of SiO{sub 2} films prepared by thermal oxidation. As the r.f. power of ICP applied more than 1250 Watts, still only the (111) diffraction peak is observed by XRD, which implies a very strong preferred orientation or single crystal structure. Too low or too high r.f. power both produces amorphous SiO{sub 2} films. From the I-V curve, the MIS device with a SiO{sub 2} dielectric film has a lower leakage current density of 6.8x10{sup -8}A/cm{sup 2} at 1V as the film prepared at 1750 watts. The highest breakdown field in this study is 15.8 MV/cm. From the FTIR analysis, it was found that more hydrogen atoms incorporate into films and form Si-OH bonds as the r.f. power increases. The existence of Si-OH bonds leads to a poor reliability of the MIS device.

  18. Electrocatalysts with platinum, cobalt and nickel preparations by mechanical alloyed and CVD for the reaction of oxygen reduction; Electrocatalizadores a base de platino, cobalto y niquel preparados por aleado mecanico y CVD para la reaccion de reduccion de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, M A [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    In this research, the molecular oxygen reduction reaction (ORR) was investigated on electrocatalysts of Co, Ni, Pt and their alloys CoNi, PtCo, PtNi and PtCoNi by using H{sub 2}SO{sub 4} 0.5 and KOH 0.5 M solutions as electrolytes. The electrocatalysts were synthesized by Mechanical Alloying (MA) and Chemical Vapor Deposition (CVD) processes. For MA, metallic powders were processed during 20 h of milling in a high energy SPEX 8000 mill. For CVD, a hot-wall reactor was utilized and Co, Ni and Pt acetilactetonates were used as precursors. Films were deposited at a total pressure of 1 torr and temperatures of 400-450 C. Electrocatalysts were characterized by X-Ray Diffraction (XRD). Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-Ray Spectroscopy (EDS). Electrocatalysts prepared by mechanical alloying showed a homogeneously dispersed agglomeration of particles with nano metric size. Electrocatalysts obtained by CVD showed, in some cases, non uniform films, with particles of nano metric size, as well. The electrocatalytic performance was evaluated by using the Rotating Disk Electrode technique (RDE). Electrocatalysts prepared by MA showed higher activity than those obtained by CVD. All electrocatalysts were evaluated in alkaline media. Only electrocatalysts containing Pt were evaluated in acid media, because those materials with Co, Ni and their alloys showed instability in acidic media. Most electrocatalysts followed a mechanism for the ORR producing a certain proportion of H{sub 2}O{sub 2}. All electrocatalysts, exhibited a fair or good electrocatalytic activity in comparison with other similar reported materials. It was found that MA and CVD are appropriate processes to prepare electrocatalysts for the ORR with particles of nano metric size and performing with an acceptable catalytic activity. PtCoNi 70-23-7% by MA and PtCoNi-CVD electrocatalysts showed the highest activity in alkaline media, while in acidic

  19. Fish consumption and its motives in households with versus without self-reported medical history of CVD: A consumer survey from five European countries

    Directory of Open Access Journals (Sweden)

    Brunsø Karen

    2008-09-01

    Full Text Available Abstract Background The purpose of this study was to explore the cross-cultural differences in the frequency of fish intake and in motivations for fish consumption between people from households with (CVD+ or without (CVD- medical history of cardiovascular disease, using data obtained in five European countries. Methods A cross-sectional consumer survey was carried out in November-December 2004 with representative household samples from Belgium, the Netherlands, Denmark, Poland and Spain. The sample consisted of 4,786 respondents, aged 18–84 and who were responsible for food purchasing and cooking in the household. Results Individuals from households in the CVD+ group consumed fish more frequently in Belgium and in Denmark as compared to those in the CVD- group. The consumption of fatty fish, which is the main sources of omega-3 PUFA associated with prevention of cardiovascular diseases, was on the same level for the two CVD groups in the majority of the countries, except in Belgium where CVD+ subjects reported to eat fatty fish significantly more frequently than CVD- subjects. All respondents perceived fish as a very healthy and nutritious food product. Only Danish consumers reported a higher subjective and objective knowledge related to nutrition issues about fish. In the other countries, objective knowledge about fish was on a low level, similar for CVD+ as for CVD- subjects, despite a higher claimed use of medical information sources about fish among CVD+ subjects. Conclusion Although a number of differences between CVD- and CVD+ subjects with respect to their frequency of fish intake are uncovered, the findings suggest that fish consumption traditions and habits – rather than a medical history of CVD – account for large differences between the countries, particularly in fatty fish consumption. This study exemplifies the need for nutrition education and more effective communication about fish, not only to the people facing chronic

  20. Systematic study on synthesis and purification of double-walled carbon nanotubes synthesized via CVD

    Science.gov (United States)

    Jedrzejewska, A.; Kalenczuk, R. J.; Mijowska, E.

    2011-12-01

    Carbon nanotubes have unique properties, such as thermal and electrical conductance, which could be useful in the fields of aerospace, microelectronics and biotechnology. However, these properties may vary widely depending on the dimensions, uniformity and purity of the nanotube. Nanotube samples typically contain a significant percentage of more allotropes forms of carbon as well as metal particles left over from catalysts used in manufacturing. Purity characterization of double-walled carbon nanotubes (DWCNTs) is an increasingly popular topic in the field of carbon nanotechnology. In this study, DWCNTs were synthesized in a catalytic reaction, using Fe:MgO as catalyst and methane or methane/ethanol as carbon feedstock for chemical vapor deposition (CVD). The addition of ethanol as carbon feedstock allowed to investigate the influence of oxygen on the sample quality. The purification of the as-produced material from the metallic particles and the catalyst support was performed by sonication in an acid solution. The influence of the duration of the acid treatment using ultrasound on the sample purity was investigated, and the optimal value of this parameter was found. Transmission electron microscopy (TEM) images confirmed the removal of impurities and served to elucidate the morphology of the samples. The purity of carbon nanotubes was analyzed using thermal gravimetric analysis (TGA). The Raman spectra of the samples, as a measure of the concentration of defects, were also reported.

  1. [Application of Raman spectroscopy to investigation of CVD-SIC fiber].

    Science.gov (United States)

    Liu, Bin; Yang, Yan-Qing; Luo, Xian; Huang, Bin

    2011-11-01

    The CVD-SiC fiber was studied by using laser Raman spectra. It was found that the sharp TO peak exists in the first SiC deposit layer, indicating the larger SiC grains. But the second SiC deposit layer is with small grains. Raman peak of carbon and silicon was detected respectively in the first and second layer. Compared with that of the single SiC fiber, the TO peaks move to the high wave number for the SiC fiber in SiC(f)/Ti-6Al-4V composite. It indicates that the compressive thermal residual stress is present in the SiC fiber during the fabrication of the composite because of the mismatched coefficient of thermal expansion between Ti-6Al-4V matrix and SiC fiber. The average thermal residual stress of the SiC fiber in SiC(f)/Ti-6Al-4V composite was calculated to be 318 MPa and the residual stress in first deposit layer is 436 MPa which is much higher than that in the second layer.

  2. Enhanced photoresponse characteristics of transistors using CVD-grown MoS2/WS2 heterostructures

    Science.gov (United States)

    Shan, Junjie; Li, Jinhua; Chu, Xueying; Xu, Mingze; Jin, Fangjun; Fang, Xuan; Wei, Zhipeng; Wang, Xiaohua

    2018-06-01

    Semiconductor heterostructures based on transition metal dichalcogenides provide a broad platform to research two-dimensional nanomaterials and design atomically thin devices for fundamental and applied interests. The MoS2/WS2 heterostructure was prepared on SiO2/Si substrate by chemical vapor deposition (CVD) in our research. And the optical properties of the heterostructure was characterized by Raman and photoluminescence (PL) spectroscopy. The similar 2 orders of magnitude decrease of PL intensity in MoS2/WS2 heterostructures was tested, which is attribute to the electrical and optical modulation effects are connected with the interfacial charge transfer between MoS2 and WS2 films. Using MoS2/WS2 heterostructure as channel material of the phototransistor, we demonstrated over 50 folds enhanced photoresponsivity of multilayer MoS2 field-effect transistor. The results indicate that the MoS2/WS2 films can be a promising heterostructure material to enhance the photoresponse characteristics of MoS2-based phototransistors.

  3. Characteristics of CVD graphene nanoribbon formed by a ZnO nanowire hardmask

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chang Goo; Kang, Jang Won; Lee, Seung Yong; Hwang, Hyeon Jun; Lee, Young Gon; Park, Seong-Ju; Lee, Byoung Hun [School of Material Science and Engineering, Gwangju Institute of Science and Technology, Oryong-dong 1, Buk-gu, Gwangju, 500-712 (Korea, Republic of); Lee, Sang Kyung; Cho, Chun Hum [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Oryong-dong 1, Buk-gu, Gwangju, 500-712 (Korea, Republic of); Heo, Jinseong; Chung, Hyun-Jong; Yang, Heejun [Semiconductor Devices Lab, Samsung Advanced Institute of Technology, Yongin (Korea, Republic of); Seo, Sunae [Department of Physics, Sejong University, Gunja-Dong, Kwanggin-gu, Seoul (Korea, Republic of); Ko, Ki Young; Ahn, Jinho, E-mail: bhl@gist.ac.kr [Division of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul, 133-791 (Korea, Republic of)

    2011-07-22

    A graphene nanoribbon (GNR) is an important basic structure to open a bandgap in graphene. The GNR processes reported in the literature are complex, time-consuming, and expensive; moreover, the device yield is relatively low. In this paper, a simple new process to fabricate a long and straight graphene nanoribbon with a high yield has been proposed. This process utilizes CVD graphene substrate and a ZnO nanowire as the hardmask for patterning. 8 {mu}m long and 50-100 nm wide GNRs were successfully demonstrated in high density without any trimming, and {approx} 10% device yield was realized with a top-down patterning process. After passivating the surfaces of the GNRs using a low temperature atomic layer deposition (ALD) of Al{sub 2}O{sub 3}, high performance GNR MOSFETs with symmetric drain-current-gate-voltage (I{sub d}-V{sub g}) curves were demonstrated and a field effect mobility up to {approx} 1200 cm{sup 2} V{sup -1} s{sup -1} was achieved at V{sub d} = 10 mV.

  4. Electrochemical Energy Storage Applications of CVD Grown Niobium Oxide Thin Films.

    Science.gov (United States)

    Fiz, Raquel; Appel, Linus; Gutiérrez-Pardo, Antonio; Ramírez-Rico, Joaquín; Mathur, Sanjay

    2016-08-24

    We report here on the controlled synthesis, characterization, and electrochemical properties of different polymorphs of niobium pentoxide grown by CVD of new single-source precursors. Nb2O5 films deposited at different temperatures showed systematic phase evolution from low-temperature tetragonal (TT-Nb2O5, T-Nb2O5) to high temperature monoclinic modifications (H-Nb2O5). Optimization of the precursor flux and substrate temperature enabled phase-selective growth of Nb2O5 nanorods and films on conductive mesoporous biomorphic carbon matrices (BioC). Nb2O5 thin films deposited on monolithic BioC scaffolds produced composite materials integrating the high surface area and conductivity of the carbonaceous matrix with the intrinsically high capacitance of nanostructured niobium oxide. Heterojunctions in Nb2O5/BioC composites were found to be beneficial in electrochemical capacitance. Electrochemical characterization of Nb2O5/BioC composites showed that small amounts of Nb2O5 (as low as 5%) in conjunction with BioCarbon resulted in a 7-fold increase in the electrode capacitance, from 15 to 104 F g(-1), while imparting good cycling stability, making these materials ideally suited for electrochemical energy storage applications.

  5. Parametric optimization during machining of AISI 304 Austenitic Stainless Steel using CVD coated DURATOMIC cutting insert

    Directory of Open Access Journals (Sweden)

    M. Kaladhar

    2012-08-01

    Full Text Available In this work, Taguchi method is applied to determine the optimum process parameters for turning of AISI 304 austenitic stainless steel on CNC lathe. A Chemical vapour deposition (CVD coated cemented carbide cutting insert is used which is produced by DuratomicTM technology of 0.4 and 0.8 mm nose radii. The tests are conducted at four levels of Cutting speed, feed and depth of cut. The influence of these parameters are investigated on the surface roughness and material removal rate (MRR. The Analysis Of Variance (ANOVA is also used to analyze the influence of cutting parameters during machining. The results revealed that cutting speed significantly (46.05% affected the machined surface roughness values followed by nose radius (23.7%. The influence of the depth of cut (61.31% in affecting material removal rate (MRR is significantly large. The cutting speed (20.40% is the next significant factor. Optimal range and optimal level of parameters are also predicted for responses.

  6. Effect of substrate bias on deposition behaviour of charged silicon nanoparticles in ICP-CVD process

    International Nuclear Information System (INIS)

    Yoo, Seung-Wan; Kim, Jung-Hyung; Seong, Dae-Jin; You, Shin-Jae; Seo, Byong-Hoon; Hwang, Nong-Moon

    2017-01-01

    The effect of a substrate bias on the deposition behaviour of crystalline silicon films during inductively coupled plasma chemical vapour deposition (ICP-CVD) was analysed by consideration of non-classical crystallization, in which the building block is a nanoparticle rather than an individual atom or molecule. The coexistence of positively and negatively charged nanoparticles in the plasma and their role in Si film deposition are confirmed by applying bias voltages to the substrate, which is sufficiently small as not to affect the plasma potential. The sizes of positively and negatively charged nanoparticles captured on a carbon membrane and imaged using TEM are, respectively, 2.7–5.5 nm and 6–13 nm. The film deposited by positively charged nanoparticles has a typical columnar structure. In contrast, the film deposited by negatively charged nanoparticles has a structure like a powdery compact with the deposition rate about three times higher than that for positively charged nanoparticles. All the films exhibit crystallinity even though the substrate is at room temperature, which is attributed to the deposition of crystalline nanoparticles formed in the plasma. The film deposited by negatively charged nanoparticles has the highest crystalline fraction of 0.84. (paper)

  7. Ultrafast electron-optical phonon scattering and quasiparticle lifetime in CVD-grown graphene.

    Science.gov (United States)

    Shang, Jingzhi; Yu, Ting; Lin, Jianyi; Gurzadyan, Gagik G

    2011-04-26

    Ultrafast quasiparticle dynamics in graphene grown by chemical vapor deposition (CVD) has been studied by UV pump/white-light probe spectroscopy. Transient differential transmission spectra of monolayer graphene are observed in the visible probe range (400-650 nm). Kinetics of the quasiparticle (i.e., low-energy single-particle excitation with renormalized energy due to electron-electron Coulomb, electron-optical phonon (e-op), and optical phonon-acoustic phonon (op-ap) interactions) was monitored with 50 fs resolution. Extending the probe range to near-infrared, we find the evolution of quasiparticle relaxation channels from monoexponential e-op scattering to double exponential decay due to e-op and op-ap scattering. Moreover, quasiparticle lifetimes of mono- and randomly stacked graphene films are obtained for the probe photon energies continuously from 1.9 to 2.3 eV. Dependence of quasiparticle decay rate on the probe energy is linear for 10-layer stacked graphene films. This is due to the dominant e-op intervalley scattering and the linear density of states in the probed electronic band. A dimensionless coupling constant W is derived, which characterizes the scattering strength of quasiparticles by lattice points in graphene.

  8. Luminescence and conductivity studies on CVD diamond exposed to UV light

    CERN Document Server

    Bizzarri, A; Bruzzi, M; Sciortino, S

    1999-01-01

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination ...

  9. Luminescence and conductivity studies on CVD diamond exposed to UV light

    Science.gov (United States)

    Bizzarri, A.; Bogani, F.; Bruzzi, M.; Sciortino, S.

    1999-04-01

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination from bound states rather than due to radiative free to bound transitions, as generally assumed in TL theory. The TSC signal is likely to arise from impurity band rather than from free carriers conduction.

  10. Luminescence and conductivity studies on CVD diamond exposed to UV light

    International Nuclear Information System (INIS)

    Bizzarri, A.; Bogani, F.; Bruzzi, M.; Sciortino, S.

    1999-01-01

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination from bound states rather than due to radiative free to bound transitions, as generally assumed in TL theory. The TSC signal is likely to arise from impurity band rather than from free carriers conduction

  11. Luminescence and conductivity studies on CVD diamond exposed to UV light

    Energy Technology Data Exchange (ETDEWEB)

    Bizzarri, A.; Bogani, F.; Bruzzi, M.; Sciortino, S

    1999-04-21

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination from bound states rather than due to radiative free to bound transitions, as generally assumed in TL theory. The TSC signal is likely to arise from impurity band rather than from free carriers conduction.

  12. Successful comeback of the single-dose live oral cholera vaccine CVD 103-HgR.

    Science.gov (United States)

    Herzog, Christian

    2016-01-01

    Effective and easy to administer cholera vaccines are in need more than ever, for at risk populations and travellers alike. In many parts of the world cholera is still endemic, causing outbreaks and constituting repeatedly serious public health problems. The oral live cholera vaccine CVD 103-HgR (Orochol, Mutachol), the first genetically modified organism (GMO) used as vaccine, was in its time (launched 1993, Switzerland) the ideal cholera vaccine: single-dose, protective efficacy of 80-100% against moderate to severe cholera, acting within 8 days and exhibiting excellent safety, indiscernible from placebo. However, there were strong headwinds: In the 1990s the indication for cholera vaccines was generally downplayed by experts and in 1997 the European Commission called for a moratorium of GMOs which blocked the registration in the European Union. Thus, demand for this vaccine remained low and in 2003 it was taken off the market for economic reasons. After a decade in obscurity it (Vaxchora) has resurfaced again, now produced in the U.S. and equipped with a U.S. FDA license (June 10, 2016). What had happened? This commentary gives a critical account of an almost unbelievable string of misadventures, emerging adverse circumstances and man-made failures which nearly killed this single-dose live oral cholera vaccine. The good news is that patience and persistence lead to success in the end, allowing good science to prevail for the benefit of those in need. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Deposition uniformity, particle nucleation and the optimum conditions for CVD in multi-wafer furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, S.K.; Nilson, R.H.

    1996-06-01

    A second-order perturbation solution describing the radial transport of a reactive species and concurrent deposition on wafer surfaces is derived for use in optimizing CVD process conditions. The result is applicable to a variety of deposition reactions and accounts for both diffusive and advective transport, as well as both ordinary and Knudsen diffusion. Based on the first-order approximation, the deposition rate is maximized subject to a constraint on the radial uniformity of the deposition rate. For a fixed reactant mole fraction, the optimum pressure and optimum temperature are obtained using the method of Lagrange multipliers. This yields a weak one-sided maximum; deposition rates fall as pressures are reduced but remain nearly constant at all pressures above the optimum value. The deposition rate is also maximized subject to dual constraints on the uniformity and particle nucleation rate. In this case, the optimum pressure, optimum temperature and optimum reactant fraction are similarly obtained, and the resulting maximum deposition rate is well defined. These results are also applicable to CVI processes used in composites manufacturing.

  14. Aluminum-silicon co-deposition by FB-CVD on austenitic stainless steel AISI 316

    International Nuclear Information System (INIS)

    Marulanda, J L; Perez, F J; Remolina-Millán, A

    2013-01-01

    Aluminum-silicon coatings were deposited on stainless steel AISI 316 in the temperature range of 540 to 560°C by CVD-FBR. It was used a fluidized bed with 2.5% silicon and 7.5% aluminum powder and 90% inert (alumina). This bed was fluidized with Ar and as an activator a mixture of HCl/H2 in ratios of 1/10 to 1/16. Furthermore, the deposition time of the coatings was varied between 45 minutes to 1.5 hours, with a 50% active gas, neutral gases 50%. Thermodynamic simulation was conducted with the Thermocalc software to get the possible compositions and amount of material deposited for the chosen conditions. The coatings presented the follow compounds FeAl 2 Si, FeAl 2 and Fe 2 Al 5 . Aluminum-silicon coatings were heat treated to improve its mechanical properties and its behavior against oxidation for the inter diffusion of the alloying elements. The heat treatment causes the aluminum diffuse into the substrate and the iron diffuse into coating surface. This leads to the transformation of the above compounds in FeAl, Al 2 FeSi, Cr 3 Si, AlFeNi and AlCrFe

  15. Direct dry transfer of CVD graphene to an optical substrate by in situ photo-polymerization

    Science.gov (United States)

    Kessler, Felipe; Muñoz, Pablo A. R.; Phelan, Ciaran; Romani, Eric C.; Larrudé, Dunieskys R. G.; Freire, Fernando L.; Thoroh de Souza, Eunézio A.; de Matos, Christiano J. S.; Fechine, Guilhermino J. M.

    2018-05-01

    Here, we report on a method that allows graphene produced by chemical vapor deposition (CVD) to be directly transferred to an optically transparent photo resin, by in situ photo-polymerization of the latter, with high efficiency and low contamination. Two photocurable resins, A and B, with different viscosities but essentially the same chemical structure, were used. Raman spectroscopy and surface energy results show that large continuous areas of graphene were transferred with minimal defects to the lower viscosity resin (B), due to the better contact between the resin and graphene. As a proof-of-principle optical experiment, graphene on the polymeric substrate was subjected to high-intensity femtosecond infrared pulses and third-harmonic generation was observed with no noticeable degradation of the sample. A sheet third-order susceptibility χ (3) = 0.71 ×10-28m3V-2 was obtained, matching that of graphene on a glass substrate. These results indicate the suitability of the proposed transfer method, and of the photo resin, for the production of nonlinear photonic components and devices.

  16. Thermoluminescence characterization of CVD diamond film exposed to UV and beta radiation

    International Nuclear Information System (INIS)

    Barboza-Flores, M.; Melendrez, R.; Gastelum, S.; Chernov, V.; Bernal, R.; Cruz-Vazquez, C.; Brown, F.; Pedroza-Montero, M.; Gan, B.; Ahn, J.; Zhang, Q.; Yoon, S.F.

    2003-01-01

    Thermoluminescence (TL) properties of diamond films grown by microwave and hot filament CVD techniques were studied. The main purpose of the present work was to characterize the thermoluminescence response of diamond films to ultraviolet and beta radiation. The thermoluminescence excitation spectrum exhibits maximum TL efficiency around 210-215 nm. All samples presented a glow curve composed of at least one TL peak and showed regions of linear as well as supralinear behavior as a function or irradiation dose. The linear dose dependence was found for up to sixteen minutes of monochromatic UV irradiation and 300 Gy for beta irradiated samples. The activation energy and the frequency factor were determined and found in the range of 0.33-1.7 eV and 5.44 x 10 2 -5.67 x 10 16 s -1 , respectively. The observed TL performance is reasonable appropriate to justify further investigation of diamond films as radiation dosimeters keeping in mind that diamond is an ideal TL dosemeter since it is tissue-equivalent and biological compatible. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Synthesis and characterization of organosilicon compounds as novel precursors for CVD processes

    Energy Technology Data Exchange (ETDEWEB)

    Ermakova, E.N.; Sysoev, S.V.; Nikulina, L.D. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Acad. Lavrentiev Ave. 3, Novosibirsk 630090 (Russian Federation); Tsyrendorzhieva, I.P.; Rakhlin, V.I. [Favorskii Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorskii Str. 1, Irkutsk 664033 (Russian Federation); Kosinova, M.L., E-mail: marina@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Acad. Lavrentiev Ave. 3, Novosibirsk 630090 (Russian Federation)

    2015-12-20

    Highlights: • The temperature dependences of vapor pressure of four precursors have been measured. • The experimental data were used to calculate standard thermodynamic functions. • The thermodynamic modelling of SiC{sub x}N{sub y} films formation has been performed. - Abstract: Chemical vapor deposition using single-source organosilicon precursors is one of the most effective ways to produce multifunctional SiC{sub x}N{sub y} films. It is worth mentioning that the precursor molecule design affects both the composition and properties of films. Four organosilicon compounds containing a phenyl substituent (namely, trimethylphenylsilane, trimethyl(phenylamino) silane, trimethyl(benzylamino)silane and bis(trimethylsilyl)phenylamine) have been synthesized and characterized as potential CVD precursors for SiC{sub x}N{sub y} films synthesis. The compounds have been shown to be volatile and stable enough to be used in chemical vapor deposition of SiC{sub x}N{sub y} films. Thermodynamic modeling of the film deposition from the gaseous mixture of trimethylphenylsilane and ammonia in Si–C–N–H system has demonstrated that SiC{sub x}N{sub y} films can be deposited, and there is an opportunity to determine the area of appropriate deposition conditions.

  18. Ti:Pt:Au:Ni thin-film CVD diamond sensor ability for charged particle detection.

    Science.gov (United States)

    Kasiwattanawut, Haruetai; Tchouaso, Modeste Tchakoua; Prelas, Mark A

    2018-05-22

    This work demonstrates the development of diamond sensors with reliable contacts using a new metallization formula, which can operate under high-pressure gas environment. The metallization was created using thin film layers of titanium, platinum, gold and nickel deposited on a single crystal electronic grade CVD diamond chip. The contacts were 2 mm in diameter with thickness of 50/5/20/150 nm of Ti:Pt:Au:Ni. The optimum operating voltage of the sensor was determined from the current-voltage measurements. The sensor was calibrated with 239 Pu and 241 Am alpha radiation sources at 300 V. The energy resolution of the Ti:Pt:Au:Ni diamond sensor was determined to be 7.6% at 5.2 MeV of 239 Pu and 2.2% at 5.48 MeV of 241 Am. The high-pressure gas loading environment under which this sensor was used is discussed. Specifically, experimental observations are described using hydrogen loading of nickel as a means of initiating low energy nuclear reactions. No neutrons, electrons, ions or other ionizing radiations were observed in these experiments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Growth of high quality AlN films on CVD diamond by RF reactive magnetron sputtering

    Science.gov (United States)

    Chen, Liang-xian; Liu, Hao; Liu, Sheng; Li, Cheng-ming; Wang, Yi-chao; An, Kang; Hua, Chen-yi; Liu, Jin-long; Wei, Jun-jun; Hei, Li-fu; Lv, Fan-xiu

    2018-02-01

    A highly oriented AlN layer has been successfully grown along the c-axis on a polycrystalline chemical vapor deposited (CVD) diamond by RF reactive magnetron sputtering. Structural, morphological and mechanical properties of the heterostructure were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Nano-indentation and Four-probe meter. A compact AlN film was demonstrated on the diamond layer, showing columnar grains and a low surface roughness of 1.4 nm. TEM results revealed a sharp AlN/diamond interface, which was characterized by the presence of a distinct 10 nm thick buffer layer resulting from the initial AlN growth stage. The FWHM of AlN (002) diffraction peak and its rocking curve are as low as 0.41° and 3.35° respectively, indicating a highly preferred orientation along the c-axis. AlN sputtered films deposited on glass substrates show a higher bulk resistivity (up to 3 × 1012 Ω cm), compared to AlN films deposited on diamond (∼1010 Ω cm). Finally, the film hardness and Young's modulus of AlN films on diamond are 25.8 GPa and 489.5 GPa, respectively.

  20. Impedance study on the corrosion of PVD and CVD titanium nitride coatings

    International Nuclear Information System (INIS)

    Elsener, B.; Rota, A.; Boehni, H.

    1989-01-01

    Titanium nitride (TiN) coatings, produced by physical (PVD) or chemical (CVD) vapor deposition techniques are used routinely to improve the wear and corrosion resistance of a surface. The main problem in using TiN as a protective coating in aggressive environements are pores and pinholes in the coating where the substrate is exposed to the electrolyte. In this work, the electrochemical and corrosion behaviour of TiN films on quartz glass, carbon steel, 304 and 316 stainless steel is studied by polarization curves and electrochemical impedance spectroscopy (EIS) in hydrochloric acid. It is shown that the TiN coating can be used successfully only on substrates that passivate easily. On mild steel rapid corrosion takes place at pores in the coating due to the very noble steady state potential of the TiN coating. The interaction of the metallic substrate with the TiN coating is discussed for the two limiting cases mild steel (active) and 316SS (passive). It is shown that the determination of the coating porosity is possible for the active substrate only. On the passive substrate the occurence of an additional time constant in the high frequency region of the spectrum qualitatively indicates the presence of pores. A quality control of the coatings based on this fact might be possible. (author) 15 refs., 6 figs., 2 tabs

  1. Commissioning and first operation of the pCVD diamond ATLAS Beam Conditions Monitor

    CERN Document Server

    Dobos, D

    2009-01-01

    The main aim of the ATLAS Beam Conditions Monitor is to protect the ATLAS Inner Detector silicon trackers from high radiation doses caused by LHC beam incidents, e.g. magnet failures. The BCM uses in total 16 1x1 cm2 500 μm thick polycrystalline chemical vapor deposition (pCVD) diamond sensors. They are arranged in 8 positions around the ATLAS LHC interaction point. Time difference measurements with sub nanosecond resolution are performed to distinguish between particles from a collision and spray particles from a beam incident. An abundance of the latter leads the BCM to provoke an abort of the LHC beam. A FPGA based readout system with a sampling rate of 2.56 GHz performs the online data analysis and interfaces the results to ATLAS and the beam abort system. The BCM diamond sensors, the detector modules and their readout system are described. Results of the operation with the first LHC beams are reported and results of commissioning and timing measurements (e.g. with cosmic muons) in preparation for first ...

  2. Measurement of the secondary electron emission from CVD diamond films using phosphor screen detectors

    Science.gov (United States)

    Vaz, R.; May, P. W.; Fox, N. A.; Harwood, C. J.; Chatterjee, V.; Smith, J. A.; Horsfield, C. J.; Lapington, J. S.; Osbourne, S.

    2015-03-01

    Diamond-based photomultipliers have the potential to provide a significant improvement over existing devices due to diamond's high secondary electron yield and narrow energy distribution of secondary electrons which improves energy resolution creating extremely fast response times. In this paper we describe an experimental apparatus designed to study secondary electron emission from diamond membranes only 400 nm thick, observed in reflection and transmission configurations. The setup consists of a system of calibrated P22 green phosphor screens acting as radiation converters which are used in combination with photomultiplier tubes to acquire secondary emission yield data from the diamond samples. The superior signal voltage sampling of the phosphor screen setup compared with traditional Faraday Cup detection allows the variation in the secondary electron yield across the sample to be visualised, allowing spatial distributions to be obtained. Preliminary reflection and transmission yield data are presented as a function of primary electron energy for selected CVD diamond films and membranes. Reflection data were also obtained from the same sample set using a Faraday Cup detector setup. In general, the curves for secondary electron yield versus primary energy for both measurement setups were comparable. On average a 15-20% lower signal was recorded on our setup compared to the Faraday Cup, which was attributed to the lower photoluminescent efficiency of the P22 phosphor screens when operated at sub-kilovolt bias voltages.

  3. Low-pressure c-BN deposition - is a CVD process possible?

    International Nuclear Information System (INIS)

    Haubner, R.; Tang, X.

    2001-01-01

    Since the low-pressure diamond deposition was discovered in 1982 there is a high interest to find a similar process for the c-BN synthesis. A review about the c-BN deposition process as well as its characterization is given. Experiments with a simple chemical vapor deposition(CVD) reactor using tris(dimethylamino)borane as precursor were carried out. In a cold-wall reactor substrates were heated up by high-frequency. Argon was used as protecting and carrying the precursor, it was saturated with tris(dimethylamino)borane (precursor) according to its vapor pressure and transports the pressure to the hot substrate, where deposition occurs. WC-Co hardmetal plates containing 6 wt. % Co, Mo and Si were used as substrates. Various BN layers were deposited and characterized. X-ray diffraction, IR-spectroscopy and SIMS indicate that BN-coatings containing c-BN were deposited. However a final verification of c-BN crystallites by TEM investigations was not possible till now. (nevyjel)

  4. Growth studies of CVD-MBE by in-situ diagnostics

    Science.gov (United States)

    Maracas, George N.; Steimle, Timothy C.

    1992-10-01

    This is the final technical report for the three year DARPA-URI program 'Growth Studies of CVD-MBE by in-situ Diagnostics'. The goals of the program were to develop non-invasive, real time epitaxial growth monitoring techniques and combine them to gain an understanding of processes that occur during MBE growth from gas sources. We have adapted these techniques to a commercially designed gas source MBE system (Vacuum Generators Inc.) to facilitate technology transfer out of the laboratory into industrial environments. The in-situ measurement techniques of spectroscopic ellipsometry (SE) and laser induced fluorescence (LIF) have been successfully implemented to monitor the optical and chemical properties of the growing epitaxial film and the gas phase reactants. The ellipsometer was jointly developed with the J. Woolam Co. and has become a commercial product. The temperature dependence of group 3 and 5 desorption from GaAs and InP has been measured as well as the incident effusion cell fluxes. The temporal evolution of the growth has also been measured both by SE and LIF to show the smoothing of heterojunction surfaces during growth interruption. Complicated microcavity optical device structures have been monitored by ellipsometry in real time to improve device quality. This data has been coupled with the structural information obtained from reflection high energy electron diffraction (RHEED) to understand the growth processes in binary and ternary bulk 3-5 semiconductors and heterojunctions.

  5. Forming method of a functional layer-built film by micro-wave plasma CVD

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Keishi

    1988-11-18

    In forming an amorphous semi-conductor material film, the micro-wave plasma CVD cannot be generally used because of such demerits as film-separation, low yield, columnar structure in the film, and problems in the optical and electrical properties. In this invention, a specific substrate is placed in a layer-built film forming unit which is capable of maintaining vacuum; raw material gas for the film formation is introduced; plasma is generated by a micro-wave energy to decompose the raw material gas, thus forming the layer-built film on the substarte. Then a film is made by adding a specific amount of calcoganide-containing gas to the raw material gas. By this, the utilization efficiency of the raw material gas gets roughly 100% and both the adhesion to the substrate and the structural flexibility of the layer-built film increase, enhancing the yield of forming various functional elements (sensor, solar cell, thin transistor film, etc.), and thus greatly reducing the production cost. 6 figs., 7 tabs.

  6. Electrocatalysts with platinum, cobalt and nickel preparations by mechanical alloyed and CVD for the reaction of oxygen reduction

    International Nuclear Information System (INIS)

    Garcia C, M. A.

    2008-01-01

    In this research, the molecular oxygen reduction reaction (ORR) was investigated on electrocatalysts of Co, Ni, Pt and their alloys CoNi, PtCo, PtNi and PtCoNi by using H 2 SO 4 0.5 and KOH 0.5 M solutions as electrolytes. The electrocatalysts were synthesized by Mechanical Alloying (MA) and Chemical Vapor Deposition (CVD) processes. For MA, metallic powders were processed during 20 h of milling in a high energy SPEX 8000 mill. For CVD, a hot-wall reactor was utilized and Co, Ni and Pt acetilactetonates were used as precursors. Films were deposited at a total pressure of 1 torr and temperatures of 400-450 C. Electrocatalysts were characterized by X-Ray Diffraction (XRD). Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-Ray Spectroscopy (EDS). Electrocatalysts prepared by mechanical alloying showed a homogeneously dispersed agglomeration of particles with nano metric size. Electrocatalysts obtained by CVD showed, in some cases, non uniform films, with particles of nano metric size, as well. The electrocatalytic performance was evaluated by using the Rotating Disk Electrode technique (RDE). Electrocatalysts prepared by MA showed higher activity than those obtained by CVD. All electrocatalysts were evaluated in alkaline media. Only electrocatalysts containing Pt were evaluated in acid media, because those materials with Co, Ni and their alloys showed instability in acidic media. Most electrocatalysts followed a mechanism for the ORR producing a certain proportion of H 2 O 2 . All electrocatalysts, exhibited a fair or good electrocatalytic activity in comparison with other similar reported materials. It was found that MA and CVD are appropriate processes to prepare electrocatalysts for the ORR with particles of nano metric size and performing with an acceptable catalytic activity. PtCoNi 70-23-7% by MA and PtCoNi-CVD electrocatalysts showed the highest activity in alkaline media, while in acidic electrolyte PtCoNi 70

  7. Neonatal Phosphate Nutrition Alters <em>in em>Vivo> and <em>in em>Vitro> Satellite Cell Activity in Pigs

    Directory of Open Access Journals (Sweden)

    Chad H. Stahl

    2012-05-01

    Full Text Available Satellite cell activity is necessary for postnatal skeletal muscle growth. Severe phosphate (PO4 deficiency can alter satellite cell activity, however the role of neonatal PO4 nutrition on satellite cell biology remains obscure. Twenty-one piglets (1 day of age, 1.8 ± 0.2 kg BW were pair-fed liquid diets that were either PO4 adequate (0.9% total P, supra-adequate (1.2% total P in PO4 requirement or deficient (0.7% total P in PO4 content for 12 days. Body weight was recorded daily and blood samples collected every 6 days. At day 12, pigs were orally dosed with BrdU and 12 h later, satellite cells were isolated. Satellite cells were also cultured <em>in vitroem> for 7 days to determine if PO4 nutrition alters their ability to proceed through their myogenic lineage. Dietary PO4 deficiency resulted in reduced (<em>P> < 0.05 sera PO4 and parathyroid hormone (PTH concentrations, while supra-adequate dietary PO4 improved (<em>P> < 0.05 feed conversion efficiency as compared to the PO4 adequate group. <em>In vivoem> satellite cell proliferation was reduced (<em>P> < 0.05 among the PO4 deficient pigs, and these cells had altered <em>in vitroem> expression of markers of myogenic progression. Further work to better understand early nutritional programming of satellite cells and the potential benefits of emphasizing early PO4 nutrition for future lean growth potential is warranted.

  8. Genetic diversity of tropical-adapted onion germplasm assessed by RAPD markers Diversidade genética em germoplasma tropical de cebola estimada via marcadores RAPD

    Directory of Open Access Journals (Sweden)

    Maria do Desterro M dos Santos

    2012-03-01

    relation to main 'Baia Periforme' group. This germplasm displayed a relatively low genetic diversity, with the predominance of materials originated from the base population 'Baia Periforme'. There are, however, some accessions, which can add genetic diversity to this germplasm and they can be exploited by onion breeding programs aiming to develop cultivars for tropical regions of the world.A cebola é uma cultura de expressiva importância socioeconômica para o Brasil. Marcantes contribuições para o desenvolvimento da cultura têm sido feitas utilizando-se germoplasma de cebola adaptado às regiões tropicais e subtropicais. Nesse contexto, o presente trabalho teve como objetivo estudar a diversidade genética existente em uma coleção de germoplasma potencialmente útil ao desenvolvimento de cultivares para essas regiões. Para isso, a variabilidade genética de um grupo de 21 acessos foi analisada via marcadores RAPD. Esses acessos ('Red Creole', 'Roxa IPA-3', 'Valenciana 14', 'Beta Cristal', 'Diamante', 'Composto IPA-6', 'Aurora', 'Bojuda Rio Grande', 'Alfa Tropical', 'Pêra IPA-4', 'Primavera', 'Belém IPA-9', 'Crioula Alto Vale', 'Conquista', 'Pira-Ouro', 'Vale-Ouro IPA-11', 'Franciscana IPA-10', 'Serrana', 'CNPH 6400', 'Petroline' e 'Baia Periforme' têm sido empregados como germoplasma e/ou foram desenvolvidos pelos programas de melhoramento genético de cebola conduzidos no Brasil. Dos 520 iniciadores ('primers' utilizados na triagem inicial, somente 38 confirmaram polimorfismos entre os 21 acessos. Esses 38 'primers' produziram 624 amplicons, dos quais 522 (83,7% foram monomórficos e 102 (16,3% polimórficos. Com base nos padrões revelados, seis grupos foram formados de acordo com a similaridade média global entre os acessos (= 0,72. Somente um desses seis grupos englobou mais de um acesso. O grupo principal (formado por 16 acessos incluiu, predominantemente, as cultivares que apresentam no seu pedigree a contribuição de 'Baia Periforme' ('Diamante

  9. Constituents from <em>Vigna em>vexillata> and Their Anti-Inflammatory Activity

    Directory of Open Access Journals (Sweden)

    Guo-Feng Chen

    2012-08-01

    Full Text Available The seeds of <em>Vigna em>genus are important food resources and there have already been many reports regarding their bioactivities. In our preliminary bioassay, the chloroform layer of methanol extracts of<em> V. vexillata em>demonstrated significant anti-inflammatory bioactivity. Therefore, the present research is aimed to purify and identify the anti-inflammatory principles of <em>V. vexillataem>. One new sterol (1 and two new isoflavones (2,3 were reported from the natural sources for the first time and their chemical structures were determined by the spectroscopic and mass spectrometric analyses. In addition, 37 known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Among the isolates, daidzein (23, abscisic acid (25, and quercetin (40 displayed the most significant inhibition of superoxide anion generation and elastase release.

  10. Flash-lamp-crystallized polycrystalline silicon films with high hydrogen concentration formed from Cat-CVD a-Si films

    International Nuclear Information System (INIS)

    Ohdaira, Keisuke; Tomura, Naohito; Ishii, Shohei; Matsumura, Hideki

    2011-01-01

    We investigate residual forms of hydrogen (H) atoms such as bonding configuration in poly-crystalline silicon (poly-Si) films formed by the flash-lamp-induced crystallization of catalytic chemical vapor deposited (Cat-CVD) a-Si films. Raman spectroscopy reveals that at least part of H atoms in flash-lamp-crystallized (FLC) poly-Si films form Si-H 2 bonds as well as Si-H bonds with Si atoms even using Si-H-rich Cat-CVD a-Si films, which indicates the rearrangement of H atoms during crystallization. The peak desorption temperature during thermal desorption spectroscopy (TDS) is as high as 900 o C, similar to the reported value for bulk poly-Si.

  11. Deposition and Characterization of CVD-Grown Ge-Sb Thin Film Device for Phase-Change Memory Application

    Directory of Open Access Journals (Sweden)

    C. C. Huang

    2012-01-01

    Full Text Available Germanium antimony (Ge-Sb thin films with tuneable compositions have been fabricated on SiO2/Si, borosilicate glass, and quartz glass substrates by chemical vapour deposition (CVD. Deposition takes place at atmospheric pressure using metal chloride precursors at reaction temperatures between 750 and 875°C. The compositions and structures of these thin films have been characterized by micro-Raman, scanning electron microscope (SEM with energy dispersive X-ray analysis (EDX and X-ray diffraction (XRD techniques. A prototype Ge-Sb thin film phase-change memory device has been fabricated and reversible threshold and phase-change switching demonstrated electrically, with a threshold voltage of 2.2–2.5 V. These CVD-grown Ge-Sb films show promise for applications such as phase-change memory and optical, electronic, and plasmonic switching.

  12. Diagramas de fase CVD para la preparación de películas de iridio

    Directory of Open Access Journals (Sweden)

    Hernández-Pérez, M. A.

    2002-02-01

    Full Text Available Chemical vapor deposition (CVD phase diagrams for the preparation of iridium films were calculated using Gibbs free energy minimization method. Iridium acetylacetonate (Ir(acac3 was used as the precursor compound. Two gaseous mixtures were analyzed: Ir(acac3-O2-Ar and Ir(acac3-Ar. The deposition temperatures were explored from 300 to 800 °C, total pressures from 13.3 to 13.332 Pa and partial pressures of Ir(acac3 gas and O2 gas from 0.001 to 1.000 Pa. The Ir-CVD diagrams predicted that without Oj gas in the gaseous mixture, the solid films consist of two solid phases: Ir+C. In contrast, with addition of O2 to the gaseous mixture, the Ir-CVD diagrams revealed different domains of condensed phases which include IrO2, IrO2+Ir, Ir and Ir+C. These diagrams allow one to establish the total pressures and temperatures required to obtain a given film composition. The results predicted by the Ir-CVD diagrams are in good agreement with those experimentally obtained.

    Se calcularon los diagramas de fase CVD (Chemical Vapor Deposition para la preparación de películas de iridio empleando el método de minimización de la energía libre de Gibbs. Como precursor se utilizó acetilacetonato de iridio (Ir(acac3. Se analizaron las mezclas gaseosas Ir(acac3-O2Ar e Ir(acac3-Ar. Las temperaturas de depósito se exploraron desde 300 hasta 800 °C, las presiones totales de 13,3 a 13.332 Pa y las presiones parciales de los gases Ir(acac3 y O2 desde 0,001 hasta 1.000 Pa. Los diagramas Ir-CVD predicen que sin O2 en la mezcla gaseosa, las películas constan de las fases sólidas Ir+C. En contraste, con adición de O2 los diagramas Ir-CVD revelan diferentes dominios de fases sólidas que incluyen IrO2, IrO2+Ir, Ir e Ir+C. Estos diagramas permiten establecer

  13. GaN-based FETs using Cat-CVD SiN passivation for millimeter-wave applications

    International Nuclear Information System (INIS)

    Higashiwaki, Masataka; Mimura, Takashi; Matsui, Toshiaki

    2008-01-01

    We have found that SiN passivation by catalytic chemical vapor deposition (Cat-CVD) can significantly increase an electron density of an AlGaN/GaN heterostructure field-effect transistor (HFET). This effect enables thin-barrier HFET structures to have a high-density two-dimensional electron gas and leads to suppression of short-channel effects. We fabricated 30-nm-gate Al 0.4 Ga 0.6 N(8 nm)/GaN HFETs using Cat-CVD SiN. The maximum drain current density and extrinsic transconductance were 1.49 A/mm and 402 mS/mm, respectively. Current-gain cutoff frequency and maximum oscillation frequency of the HFETs were 181 and 186 GHz, respectively. These high-frequency device characteristics are sufficiently high enough for millimeter-wave applications

  14. Co-morbid depression is associated with poor work outcomes in persons with cardiovascular disease (CVD: A large, nationally representative survey in the Australian population

    Directory of Open Access Journals (Sweden)

    O'Neil Adrienne

    2012-01-01

    Full Text Available Abstract Background Co-morbid major depressive disorder (MDD and cardiovascular disease (CVD is associated with poor clinical and psychological outcomes. However, the full extent of the burden of, and interaction between, this co-morbidity on important vocational outcomes remains less clear, particularly at the population level. We examine the association of co-morbid MDD with work outcomes in persons with and without CVD. Methods This study utilised cross-sectional, population-based data from the 2007 Australian National Survey of Mental Health and Wellbeing (n = 8841 to compare work outcomes of individuals with diagnostically-defined MDD and CVD, MDD but not CVD, CVD but not MDD, with a reference group of "healthy" Australians. Workforce participation was defined as being in full- or part-time employment. Work functioning was measured using a WHO Disability Assessment Schedule item. Absenteeism was assessed using the 'days out of role' item. Results Of the four groups, those with co-morbid MDD and CVD were least likely to report workforce participation (adj OR:0.4, 95% CI: 0.3-0.6. Those with MDD only (adj OR:0.8, 95% CI:0.7-0.9 and CVD only (adj OR:0.8, 95% CI: 0.6-0.9 also reported significantly reduced odds of participation. Employed individuals with co-morbid MDD and CVD were 8 times as likely to experience impairments in work functioning (adj OR:8.1, 95% CI: 3.8- 17.3 compared with the reference group. MDD was associated with a four-fold increase in impaired functioning. Further, individuals with co-morbid MDD and CVD reported greatest likelihood of workplace absenteeism (adj. OR:3.0, 95% CI: 1.4-6.6. Simultaneous exposure to MDD and CVD conferred an even greater likelihood of poorer work functioning. Conclusions Co-morbid MDD and CVD is associated with significantly poorer work outcomes. Specifically, the effects of these conditions on work functioning are synergistic. The development of specialised treatment programs for those with co

  15. Co-morbid depression is associated with poor work outcomes in persons with cardiovascular disease (CVD): A large, nationally representative survey in the Australian population

    Science.gov (United States)

    2012-01-01

    Background Co-morbid major depressive disorder (MDD) and cardiovascular disease (CVD) is associated with poor clinical and psychological outcomes. However, the full extent of the burden of, and interaction between, this co-morbidity on important vocational outcomes remains less clear, particularly at the population level. We examine the association of co-morbid MDD with work outcomes in persons with and without CVD. Methods This study utilised cross-sectional, population-based data from the 2007 Australian National Survey of Mental Health and Wellbeing (n = 8841) to compare work outcomes of individuals with diagnostically-defined MDD and CVD, MDD but not CVD, CVD but not MDD, with a reference group of "healthy" Australians. Workforce participation was defined as being in full- or part-time employment. Work functioning was measured using a WHO Disability Assessment Schedule item. Absenteeism was assessed using the 'days out of role' item. Results Of the four groups, those with co-morbid MDD and CVD were least likely to report workforce participation (adj OR:0.4, 95% CI: 0.3-0.6). Those with MDD only (adj OR:0.8, 95% CI:0.7-0.9) and CVD only (adj OR:0.8, 95% CI: 0.6-0.9) also reported significantly reduced odds of participation. Employed individuals with co-morbid MDD and CVD were 8 times as likely to experience impairments in work functioning (adj OR:8.1, 95% CI: 3.8- 17.3) compared with the reference group. MDD was associated with a four-fold increase in impaired functioning. Further, individuals with co-morbid MDD and CVD reported greatest likelihood of workplace absenteeism (adj. OR:3.0, 95% CI: 1.4-6.6). Simultaneous exposure to MDD and CVD conferred an even greater likelihood of poorer work functioning. Conclusions Co-morbid MDD and CVD is associated with significantly poorer work outcomes. Specifically, the effects of these conditions on work functioning are synergistic. The development of specialised treatment programs for those with co-morbid MDD and CVD is

  16. Sharp boron spikes in silicon grown at reduced and atmospheric pressure by fast-gas-switching CVD

    NARCIS (Netherlands)

    Vink, A.T.; Roksnoer, P.J.; Maes, J.W.F.M.; Vriezema, C.J.; IJzendoorn, van L.J.; Zalm, P.C.

    1990-01-01

    Boron doping spikes in Si were grown by fast-gas-switching CVD at 800 and 850°C using Si2H6 and B2H6 in 0.03, 0.1 and 1 atm H2 as the carrier gas. The B2H6 doping gas was added for 2 s by two methods, namely during growth or as a flush while the Si2H6 flow was interrupted. High-resolution SIMS

  17. Enhanced B doping in CVD-grown GeSn:B using B δ-doping layers

    Science.gov (United States)

    Kohen, David; Vohra, Anurag; Loo, Roger; Vandervorst, Wilfried; Bhargava, Nupur; Margetis, Joe; Tolle, John

    2018-02-01

    Highly doped GeSn material is interesting for both electronic and optical applications. GeSn:B is a candidate for source-drain material in future Ge pMOS device because Sn adds compressive strain with respect to pure Ge, and therefore can boost the Ge channel performances. A high B concentration is required to obtain low contact resistivity between the source-drain material and the metal contact. To achieve high performance, it is therefore highly desirable to maximize both the Sn content and the B concentration. However, it has been shown than CVD-grown GeSn:B shows a trade-off between the Sn incorporation and the B concentration (increasing B doping reduces Sn incorporation). Furthermore, the highest B concentration of CVD-grown GeSn:B process reported in the literature has been limited to below 1 × 1020 cm-3. Here, we demonstrate a CVD process where B δ-doping layers are inserted in the GeSn layer. We studied the influence of the thickness between each δ-doping layers and the δ-doping layers process conditions on the crystalline quality and the doping density of the GeSn:B layers. For the same Sn content, the δ-doping process results in a 4-times higher B doping than the co-flow process. In addition, a B doping concentration of 2 × 1021 cm-3 with an active concentration of 5 × 1020 cm-3 is achieved.

  18. Surface PIXE analysis of phosphorus in a thin SiO2 (P, B) CVD layer deposited onto Si substrate

    International Nuclear Information System (INIS)

    Roumie, M.; Nsouli, B.

    2001-01-01

    Phosphorus determination, at level of percent, in Si matrix is not an easy analytical task. The analyzed materials arc Borophosphosilicate glass which are an important component of silicon based semiconductor technology. It's a thin SiO2 layer (400 nm) doped with boron and phosphorus using, in general, CVD (Chemical Vapor Deposition) process, in order to improve its plasticity, and deposited onto Si substrate. Therefore, the mechanical behaviour of the CVD SiO2 (P, B) layer is very sensitive to the phosphorus concentration. In this work we explore the capability of FIXE (Particle Induced X-ray Emission) to monitor a rapid and accurate quantification of P which is usually very low in such materials (few percent of the thin CVD layer deposited onto a silicon substrate). A systematic study is undertaken using Proton (0.5-3 MeV energy) and helium (1-3 MeV energy) beams, different thickness of X-ray absorber (131 and 146 μm of Kapton filter) and different tilting angles (0,45,60 and 80 deg.). The optimized measurement conditions should improve the P signal detection comparing to the Si and Background ones

  19. Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Koo; Kim, Jong-Hoon; Jeong, Min-Goon; Lim, Dae-Soon [Department of Materials Science and Engineering, Korea University, Anam-Dong 5-1, Seoungbuk-Ku, Seoul 136-713 (Korea, Republic of); Song, Min-Jung, E-mail: dslim@korea.ac.kr [Center for Advanced Device Materials, Korea University, Anam-Dong 5-1, Seoungbuk-Ku, Seoul 136-713 (Korea, Republic of)

    2010-12-17

    Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a {zeta}-potential and average particle size of - 60.5 mV and {approx} 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 {+-} 0.4 x 10{sup 11} cm{sup -2}) and smooth surface were consequently fabricated.

  20. Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

    International Nuclear Information System (INIS)

    Lee, Seung-Koo; Kim, Jong-Hoon; Jeong, Min-Goon; Lim, Dae-Soon; Song, Min-Jung

    2010-01-01

    Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a ζ-potential and average particle size of - 60.5 mV and ∼ 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 ± 0.4 x 10 11 cm -2 ) and smooth surface were consequently fabricated.

  1. Pharmacological Targeting of the Atherogenic Dyslipidemia Complex: The Next Frontier in CVD Prevention Beyond Lowering LDL Cholesterol.

    Science.gov (United States)

    Xiao, Changting; Dash, Satya; Morgantini, Cecilia; Hegele, Robert A; Lewis, Gary F

    2016-07-01

    Notwithstanding the effectiveness of lowering LDL cholesterol, residual CVD risk remains in high-risk populations, including patients with diabetes, likely contributed to by non-LDL lipid abnormalities. In this Perspectives in Diabetes article, we emphasize that changing demographics and lifestyles over the past few decades have resulted in an epidemic of the "atherogenic dyslipidemia complex," the main features of which include hypertriglyceridemia, low HDL cholesterol levels, qualitative changes in LDL particles, accumulation of remnant lipoproteins, and postprandial hyperlipidemia. We briefly review the underlying pathophysiology of this form of dyslipidemia, in particular its association with insulin resistance, obesity, and type 2 diabetes, and the marked atherogenicity of this condition. We explain the failure of existing classes of therapeutic agents such as fibrates, niacin, and cholesteryl ester transfer protein inhibitors that are known to modify components of the atherogenic dyslipidemia complex. Finally, we discuss targeted repurposing of existing therapies and review promising new therapeutic strategies to modify the atherogenic dyslipidemia complex. We postulate that targeting the central abnormality of the atherogenic dyslipidemia complex, the elevation of triglyceride-rich lipoprotein particles, represents a new frontier in CVD prevention and is likely to prove the most effective strategy in correcting most aspects of the atherogenic dyslipidemia complex, thereby preventing CVD events. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  2. Momentos em freios e em embraiagens

    OpenAIRE

    Mimoso, Rui Miguel Pereira

    2011-01-01

    Dissertação para obtenção do Grau de Mestre em Mestrado Integrado em Engenharia Mecânica Nesta dissertação reúnem-se os modelos de cálculo utilizados na determinação dos momentos em freios e em embraiagens. Neste trabalho consideram-se os casos de freios e embraiagens de atrito seco e atrito viscoso. Nos freios de atrito viscoso são considerados casos em que as características dos fluidos não são induzidas, e outros em que são induzidas modificações a essas mesmas características. São a...

  3. Design and Development of an Acoustic Levitation System for Use in CVD Growth of Carbon Nanotubes

    Science.gov (United States)

    Qasem, Amal ali

    The most widely used methods for growth of carbon nanotubes (CNTs) arc discharge, laser ablation, and chemical vapor deposition (CVD). Some of these methods have difficulties, such as controlling the quality and straightness of the nanotube in the synthesis of CNTs from substrates. Also, the enhanced plasma chemical vapor deposition method with the catalyst on a substrate produces straighter, larger diameter nanotubes by the tip growth method, but they are short. The difficulty in the floating catalyst method is that the nanotubes stay in the growth furnace for short times limiting growth to about one mm length; this method also leaves many catalyst impurities. One factor that limits CNT growth in these methods is the difficulty of getting enough carbon atoms to the growth catalyst to grow long nanotubes. The motivation of this work is that longer, higher quality nanotubes could be grown by increasing growth time and by increasing carbon atom movement to catalyst. The goal of this project is to use acoustic levitation to assist chemical vapor deposition growth by trapping and vibrating the growing CNTs for better properties. Our levitation system consists of a piezoelectric transducer attached to an aluminum horn and quartz rod extending into the growth furnace. The most important elements of our methods to achieve the acoustic levitation are as follows. 1. Using COMSOL Multi-physic Simulation software to determine the length of quartz rod needed to excite standing waves for levitation in the tube furnace. 2. Determining the resonance frequency of different transducers and horns. 3. Using ultrasound measurement to determine the time of flight, velocity of sound and sound wavelength of different horns. 4. Making Aluminum horns with the appropriate lengths. 5. Using ultrasound measurement to determine the changing of quartz rod velocity of sound and length in the furnace. 6. Mounting the transducer to booster horn and aluminum cylindrical horn above a reflector to

  4. Preparación de tamices moleculares de carbono por CVD

    Directory of Open Access Journals (Sweden)

    Manso, R.

    2001-02-01

    Full Text Available Carbon molecular sieves (CMS have been prepared by chemical vapour deposition (CVD of carbon from the pyrolysis of benzene molecules on activated carbon surfaces. The pyrolysis of benzene at temperatures in the range 650-850 ºC restricts the accessibility of the micropores due to the creation of constrictions on the microporous network. Temperatures higher than 850 ºC (temperature of carbonisation add difficulties due to decomposition and sinterization processes. Low flows of nitrogen (30 mL min-1 and high benzene content (13 % produce a more uniform carbon deposition and wider micropore size distributions. The CVD process on carbons activated to different burn-offs, using temperatures below 850 ºC, flows of 150 mL min-1 and benzene content of 1 %, gives rise to microporous materials which exhibit micropore volumes around 0,25 cm3 g-1 and narrow micropore size distributions: below 0,33 nm, between 0,33-0,41 nm or between 0,41-0,54 nm. The burn-off of the activated carbon has a relative little influence on the textural properties of the CMS that mainly depend on the degree of filling originated by the carbon deposition.

    Se han preparado tamices moleculares de carbono (CMS mediante el depósito de átomos de carbono, por pirólisis de benceno, sobre la superficie de carbones activados. La pirólisis de benceno a temperaturas comprendidas entre 650-850 ºC genera el cierre progresivo de los microporos debido a la creación de constricciones en la red microporosa que limitan la accesibilidad de determinadas moléculas. El uso de temperaturas superiores a la temperatura de carbonización del precursor (850 ºC introduce complicaciones debido a la descomposición y sinterización parcial del sólido. Flujos bajos de nitrógeno (30 mL min-1 con alto contenido en benceno (13 % producen un depósito homogéneo a lo largo de las paredes y los materiales presentan distribuciones microporosas mas anchas. El depósito de carbono sobre carbones

  5. Functional materials - Study of process for CVD SiC/C composite material

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Doo Jin; Wang, Chae Chyun; Lee, Young Jin; Oh, Byung Jun [Yonsei University, Seoul (Korea)

    2000-04-01

    The CVD SiC coating techniques are the one of high functional material manufactures that improve the thermal, wear, oxidization and infiltration resistance of the surface of raw materials and extend the life of material. Silicon carbide films have been grown onto graphite substrates by low pressure chemical vapor deposition using MTS(CH{sub 3}SiCl{sub 3}) as a source precursor and H{sub 2} or N{sub 2} as a diluent gas. The experiments for temperature and diluent gas addition changes were performed. The effect of temperature from 900 deg. C to 1350 deg. C and the alteration of diluent gas species on the growth rate and structure of deposits have been studied. The experimental results showed that the deposition rate increased with increasing deposition temperature irrespective of diluent gases and reactant depletion effect increased especially at H{sub 2} diluent gas ambient. As the diluent gas added, the growth rate decreased parabolically. For N{sub 2} addition, surface morphology of leaf-like structure appeared, and for H{sub 2}, faceted structure at 1350 deg. C. The observed features were involved by crystalline phase of {beta}-SiC and surface composition with different gas ambient. We also compared the experimental results of the effect of partial pressure on the growth rate with the results of theoretical approach based on the Langmuir-Hinshelwood model. C/SiC composites were prepared by isothermal chemical vapor infiltration (ICVI). In order to fabricate the more dense C/SiC composites, a novel process of the in-situ whisker growing and filling during ICVI was devised, which was manipulated by alternating dilute gas species. The denser C/SiC composites were successfully prepared by the novel process comparing with the conventional ICVI process. 64 refs., 36 figs., 5 tabs. (Author)

  6. Improving Post-Discharge Medication Adherence in Patients with CVD: A Pilot Randomized Trial

    Directory of Open Access Journals (Sweden)

    Alfredo D. Oliveira-Filho

    2014-12-01

    Full Text Available Background: Effective interventions to improve medication adherence are usually complex and expensive. Objective: To assess the impact of a low-cost intervention designed to improve medication adherence and clinical outcomes in post-discharge patients with CVD. Method: A pilot RCT was conducted at a teaching hospital. Intervention was based on the four-item Morisky Medication Adherence Scale (MMAS-4. The primary outcome measure was medication adherence assessed using the eight-item MMAS at baseline, at 1 month post hospital discharge and re-assessed 1 year after hospital discharge. Other outcomes included readmission and mortality rates. Results: 61 patients were randomized to intervention (n = 30 and control (n = 31 groups. The mean age of the patients was 61 years (SD 12.73, 52.5% were males, and 57.4% were married or living with a partner. Mean number of prescribed medications per patient was 4.5 (SD 3.3. Medication adherence was correlated to intervention (p = 0.04 and after 1 month, 48.4% of patients in the control group and 83.3% in the intervention group were considered adherent. However, this difference decreased after 1 year, when adherence was 34.8% and 60.9%, respectively. Readmission and mortality rates were related to low adherence in both groups. Conclusion: The intervention based on a validated patient self-report instrument for assessing adherence is a potentially effective method to improve adherent behavior and can be successfully used as a tool to guide adherence counseling in the clinical visit. However, a larger study is required to assess the real impact of intervention on these outcomes.

  7. Evaluating electrically insulating films deposited on V-4% Cr-4% Ti by reactive CVD

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Cho, W.D. [Argonne National Lab., IL (United States)

    1997-04-01

    Previous CaO coatings on V-4%Cr-4%Ti exhibited high-ohmic insulator behavior even though a small amount of vanadium from the alloy was incorporated in the coating. However, when the vanadium concentration in the coatings is > 15 wt%, the coating becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. To explore this situation, CaO and Ca-V-O coatings were produced on vanadium alloys by chemical vapor deposition (CVD) and by a metallic-vapor process to investigate the electrical resistance of the coatings. Initially, the vanadium alloy specimens were either charged with oxygen in argon that contained trace levels of oxygen, or oxidized for 1.5-3 h in a 1% CO-CO{sub 2} gas mixture or in air to form vanadium oxide at 625-650{degrees}C. Most of the specimens were exposed to calcium vapor at 800-850{degrees}C. Initial and final weights were obtained to monitor each step, and surveillance samples were removed for examination by optical and scanning electron microscopy and electron-energy-dispersive and X-ray diffraction analysis; the electrical resistivity was also measured. The authors found that Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film was > 0.9, and semiconductor or conductor behavior for R < 0.8. However, in some cases, semiconductor behavior was observed when CaO-coated samples with R > 0.98 were exposed in liquid lithium. Based on these studies, the authors conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating.

  8. Extended defect related energy loss in CVD diamond revealed by spectrum imaging in a dedicated STEM

    International Nuclear Information System (INIS)

    Bangert, U.; Harvey, A.J.; Schreck, M.; Hoermann, F.

    2005-01-01

    This article aims at investigations of the low EEL region in the wide band gap system diamond. The advent of the UHV Enfina electron energy loss spectrometer combined with Digital Micrograph acquisition and processing software has made reliable detection of absorption losses below 10 eV possible. Incorporated into a dedicated STEM this instrumentation allows the acquisition of spectral information via spectrum maps (spectrum imaging) of sample areas hundreds of nanometers across, with nanometers pixel sizes, adequate spectrum statistics and 0.3 eV energy resolution, in direct correlation with microstructural features in the mapping area. We aim at discerning defect related losses at band gap energies, and discuss different routes to simultaneously process and analyse the spectra in a map. This involves extracting the zero loss peak from each spectrum and constructing ratio maps from the intensities in two energy windows, one defect related and one at a higher, crystal bandstructure dominated energy. This was applied to the residual spectrum maps and their first derivatives. Secondly, guided by theoretical EEL spectra calculations, the low loss spectra were fitted by a series of gaussian distributions. Pixel maps were constructed from amplitude ratios of gaussians, situated in the defect and the unaffected energy regime. The results demonstrate the existence of sp 2 -bonded carbon in the vicinity of stacking faults and partial dislocations in CVD diamond as well as additional states below conduction band, tailing deep into the band gap, at a node in a perfect dislocation. Calculated EEL spectra of shuffle dislocations give similar absorption features at 5-8 eV, and it is thought that this common feature is due to sp 2 -type bonding

  9. The Heartfile Lodhran CVD prevention project--end of project evaluation.

    Science.gov (United States)

    Nishtar, Sania; Badar, Asma; Kamal, Mohammad Umer; Iqbal, Azhar; Bajwa, Rashid; Shah, Tauqeer; Larik, Zahid; Karim, Fazle; Mehmood, Mahmood ul Hassan; Jehangir, Haroon; Azam, Syed Iqbal; Mirza, Yasir Abbas; Khan, Shahzad Ali; Qayyum, Aamra; Aqeel, Fauzia; Bakir, Abdul; Rahim, Ejaz

    2007-01-01

    Mainstream preventive interventions often fail to reach poor populations with a high risk of cardiovascular diseases (CVDs) in Pakistan. A community-based CVD primary prevention project aimed at developing approaches to reduce risk factors in such populations was established by Heartfile in collaboration with the National Rural Support Program in the district of Lodhran. The project implemented a range of activities integrated with existing social and health service mechanisms during a three year intervention period 2000/01-03/04. These were targeted in 4 key settings: community health education, mass media interventions, training of health professionals and health education through Lady Health Workers. The project received support from the Department for International Development, U.K. At the community level, a pre-test-post-test quasi-experimental design was used for examining project outcomes related to the community component of the intervention. Pre and post-intervention (training) evaluations were conducted involving all health care providers in randomly selected workshops in order to determine baseline levels of knowledge and the impact of training on knowledge level. In order to assess practices of physician and non-physician health care providers patient interviews, with control comparisons were conducted at each health care facility. Significant positive changes were observed in knowledge levels at a community level in the district of intervention compared with baseline knowledge levels particularly in relation to a heart healthy diet, beneficial level of physical activity, the causes of high blood pressure and heart attack and the effects of high blood pressure and active and passive smoking on health. Significant changes in behaviors at a practice level were not shown in the district of intervention. However the project played a critical role in spurring national action for the prevention and control of non-communicable diseases and introducing

  10. Metal-Free CVD Graphene Synthesis on 200 mm Ge/Si(001) Substrates.

    Science.gov (United States)

    Lukosius, M; Dabrowski, J; Kitzmann, J; Fursenko, O; Akhtar, F; Lisker, M; Lippert, G; Schulze, S; Yamamoto, Y; Schubert, M A; Krause, H M; Wolff, A; Mai, A; Schroeder, T; Lupina, G

    2016-12-14

    Good quality, complementary-metal-oxide-semiconductor (CMOS) technology compatible, 200 mm graphene was obtained on Ge(001)/Si(001) wafers in this work. Chemical vapor depositions were carried out at the deposition temperatures of 885 °C using CH 4 as carbon source on epitaxial Ge(100) layers, which were grown on Si(100), prior to the graphene synthesis. Graphene layer with the 2D/G ratio ∼3 and low D mode (i.e., low concentration of defects) was measured over the entire 200 mm wafer by Raman spectroscopy. A typical full-width-at-half-maximum value of 39 cm -1 was extracted for the 2D mode, further indicating that graphene of good structural quality was produced. The study also revealed that the lack of interfacial oxide correlates with superior properties of graphene. In order to evaluate electrical properties of graphene, its 2 × 2 cm 2 pieces were transferred onto SiO 2 /Si substrates from Ge/Si wafers. The extracted sheet resistance and mobility values of transferred graphene layers were ∼1500 ± 100 Ω/sq and μ ≈ 400 ± 20 cm 2 /V s, respectively. The transferred graphene was free of metallic contaminations or mechanical damage. On the basis of results of DFT calculations, we attribute the high structural quality of graphene grown by CVD on Ge to hydrogen-induced reduction of nucleation probability, explain the appearance of graphene-induced facets on Ge(001) as a kinetic effect caused by surface step pinning at linear graphene nuclei, and clarify the orientation of graphene domains on Ge(001) as resulting from good lattice matching between Ge(001) and graphene nucleated on such nuclei.

  11. Preparation of tantalum-based alloys by a unique CVD process

    International Nuclear Information System (INIS)

    Bryant, W.A.; Meier, G.H.

    1975-01-01

    One of the greatest problems associated with the formation of alloys by CVD is the achievement of compositional uniformity. In a typical deposition apparatus, wherein reactant gases are made to flow over the substrate in a continuous manner, this nonuniformity is inherent for two reasons. The composition of the gas stream changes as a function of its distance of travel over the substrate and, inevitably, one of the reactant compounds is more easily reduced than the other(s). This problem was overcome by the development of a process termed ''pulsing.'' In it reactant gases are periodically injected into a previously evacuated reaction chamber where they cover the substrate almost instantaneously. By this technique, gas composition at any point in time is not dependent upon distance along the substrate. Formation of alternating layers of the alloy components and subsequent homogenization allows the formation of an alloy of uniform composition with the composition being determined by the duration and relative number of the various cycles. This technique has been utilized to produce dense alloys with the composition Ta--10 wt percent W by depositing alternating layers of TA and W by the hydrogen reduction of TaCl 5 and WCl 6 . The alloys were uniform in thickness and composition over lengths in excess of 20 cm and the target composition was attained. A similar attempt to deposit a Ta--8 wt percent W--2 wt percent Hf alloy was unsuccessful because of the difficulty in reducing HfCl 4 at temperatures below those at which gas phase nucleation of Ta and W occurred (1200 and 1175 0 C respectively). 7 fig

  12. Tl and OSL dosimetry of diamond films CVD pure and unpurified with boron-carbon

    International Nuclear Information System (INIS)

    Melendrez, R.; Pedroza M, M.; Chernov, V.; Ochoa N, J.D.; Bernal, R.; Barboza F, M.; Castaneda, B.; Goncalves, J.A.N.; Sandonato, G.M.; Cruz Z, E.; Preciado F, S.; Cruz V, C.; Brown, F.; Schreck, M.

    2004-01-01

    The diamond is a material that possesses extreme physical properties, such as its hardness to the radiation, its low chemical reactivity besides its equivalence to the human tissue, which qualify him as an ideal material for radiation dosimetry. In this work, it was studied the thermal and optically stimulated response (Tl and OSL) of polycrystalline diamond films grown by the technique of CVD pure and contaminated with Boron-carbon (B/C) with the intention of characterizing their efficiency like a dosemeter for radiation in a range of 0 - 3000 Gy. For the case of the films without impurities, the Tl curve presents four main peaks, two of them in an interval of temperatures of 150-200 C and other two additional around of 250-400 C. The dependence of the response of integrated Tl and that of OSL always maintained a lineal relationship with the exhibition dose up to 100 Gy. The behavior of the films contaminated with B/C (2000 - 20000 ppm) was established through experiments that involved the signal of OSL and their relationship with the Tl response. It was found that this processes are correlated, since the electrons caught in the traps of low temperature (50 - 250 C) of the Tl they are the electrons that recombining with more probability to provide the signal of OSL. According to these results it is possible to propose the diamond films as a good candidate for dosimetry to, using the traditional technique of Tl so much as well as the but recent of OSL. (Author)

  13. Interlayers Applied to CVD Diamond Deposition on Steel Substrate: A Review

    Directory of Open Access Journals (Sweden)

    Djoille Denner Damm

    2017-09-01

    Full Text Available Academics and industry have sought after combining the exceptional properties of diamonds with the toughness of steel. Since the early 1990s several partial solutions have been found but chemical vapor deposition (CVD diamond deposition on steel substrate continues to be a persistent problem. The main drawbacks are the high carbon diffusion from gas phase into substrate, the transition metals on the material surface that catalyze sp2 bond formation, instead of sp3 bonds, and the high thermal expansion coefficient (TEC mismatch between diamond and steels. An intermediate layer has been found necessary to increase diamond adhesion. Literature has proposed many efficient intermediate layers as a diffusion barrier for both, carbon and iron, but most intermediate layers shown have not solved TEC mismatch. In this review, we briefly discuss the solutions that exclusively work as diffusion barrier and discuss in a broader way the ones that also solve, or may potentially solve, the TEC mismatch problem. We examine some multilayers, the iron borides, the chromium carbides, and vanadium carbides. We go through the most relevant results of the last two and a half decades, including recent advances in our group. Vanadium carbide looks promising since it has shown excellent diffusion barrier properties, its TEC is intermediary between diamond and steel and, it has been thickened to manage thermal stress relief. We also review a new deposition technique to set up intermediate layers: laser cladding. It is promising because of its versatility in mixing different materials and fusing and/or sintering them on a steel surface. We conclude by remarking on new perspectives.

  14. A study on the basic CVD process technology for TRISO coated particle fuel

    International Nuclear Information System (INIS)

    Choi, D. J.; Cheon, J. H.; Keum, I. S.; Lee, H. S.; Kim, J. G.

    2006-03-01

    Hydrogen energy has many advantages and is suitable as alternative energy of fossil fuel. The study of nuclear hydrogen production has performed at present. For nuclear hydrogen production, it is needed the study of VHTR(Very High Temperature Reactor) and TRISO(TRI-iSOtropic) coated fuel. TRISO coated fuel particle deposited by FBCVD(Fludized Bed CVD) method is composed of three isotropic layers: Inner Pyrolytic Carbon (IPyC), Silicon Carbide (SiC), Outer Pyrolytic Carbon (OPyC) layers. Silicon carbide was chemically vapor deposed on graphite substrate using methyltrichlorosilane (CH 3 SiCl 3 ) as a source in hydrogen atmosphere. The effect of deposition temperature and input gas ratios ( α=Q H2 /Q MTS =P H2 /P MTS ) was investigated in order to find out characteristics of silicon carbide layer. From results of those, SiC-TRISO coating deposition was conducted and achieved. Zirconium carbide layer as an advanced material of silicon carbide layer has studied. In order to find out basic properties and characteristics, studies have conducted using various methods. Zirconium carbide is chemically vapor deposed subliming zirconium tetrachloride(ZrCl 4 ) and using methan(CH 4 ) as a source in hydrogen atmosphere. Many experiments were conducted on graphite substrate about many deposition conditions such as ZrCl 4 heating temperatures and variables of H2 and CH 4 flow rate. but carbon graphite was deposited. For deposition of zirconium carbide, several different methods were approached. so zirconium carbide deposed on ZrO 2 substrate. In this experiments. source subliming type and equipment are no problems. But deposition of zirconium carbide will be continuously studied on graphite substrate approaching views of experimental way and equipment structure

  15. High-speed deposition of titanium carbide coatings by laser-assisted metal–organic CVD

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yansheng [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Tu, Rong, E-mail: turong@whut.edu.cn [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Goto, Takashi [Institute for Materials Research, Tohoku University, Aoba-ku, 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2013-08-01

    Graphical abstract: - Highlights: • A semiconductor laser was first used to prepare wide-area LCVD-TiC{sub x} coatings. • The effect of laser power for the deposition of TiC{sub x} coatings was discussed. • TiC{sub x} coatings showed a columnar cross section and a dense surface texture. • TiC{sub x} coatings had a 1–4 order lower laser density than those of previous reports. • This study gives the possibility of LCVD applying on the preparation of TiC{sub x} coating. - Abstract: A semiconductor laser-assisted chemical vapor deposition (LCVD) of titanium carbide (TiC{sub x}) coatings on Al{sub 2}O{sub 3} substrate using tetrakis (diethylamido) titanium (TDEAT) and C{sub 2}H{sub 2} as source materials were investigated. The influences of laser power (P{sub L}) and pre-heating temperature (T{sub pre}) on the microstructure and deposition rate of TiC{sub x} coatings were examined. Single phase of TiC{sub x} coatings were obtained at P{sub L} = 100–200 W. TiC{sub x} coatings had a cauliflower-like surface and columnar cross section. TiC{sub x} coatings in the present study had the highest R{sub dep} (54 μm/h) at a relative low T{sub dep} than those of conventional CVD-TiC{sub x} coatings. The highest volume deposition rate (V{sub dep}) of TiC{sub x} coatings was about 4.7 × 10{sup −12} m{sup 3} s{sup −1}, which had 3–10{sup 5} times larger deposition area and 1–4 order lower laser density than those of previous LCVD using CO{sub 2}, Nd:YAG and argon ion laser.

  16. Dermatoses em renais cronicos em terapia dialitica

    Directory of Open Access Journals (Sweden)

    Luis Alberto Batista Peres

    2014-03-01

    Full Text Available Objetivo: As desordens cutâneas e das mucosas são comuns em pacientes em hemodiálise a longo prazo. A diálise prolonga a expectativa de vida, dando tempo para a manifestação destas anormalidades. Os objetivos deste estudo foram avaliar a prevalência de problemas dermatológicos em pacientes com doença renal crônica (DRC em hemodiálise. Métodos: Cento e quarenta e cinco pacientes com doença renal crônica em hemodiálise foram estudados. Todos os pacientes foram completamente analisados para as alterações cutâneas, de cabelos, mucosas e unhas por um único examinador e foram coletados dados de exames laboratoriais. Os dados foram armazenados em um banco de dados do Microsolft Excel e analisados por estatística descritiva. As variáveis contínuas foram comparadas pelo teste t de Student e as variáveis categóricas utilizando o teste do qui-quadrado ou o teste Exato de Fischer, conforme adequado. Resultados: O estudo incluiu 145 pacientes, com idade média de 53,6 ± 14,7 anos, predominantemente do sexo masculino (64,1% e caucasianos (90,0%. O tempo médio de diálise foi de 43,3 ± 42,3 meses. As principais doenças subjacentes foram: hipertensão arterial em 33,8%, diabetes mellitus em 29,6% e glomerulonefrite crônica em 13,1%. As principais manifestações dermatológicas observadas foram: xerose em 109 (75,2%, equimose em 87 (60,0%, prurido em 78 (53,8% e lentigo em 33 (22,8% pacientes. Conclusão: O nosso estudo mostrou a presença de mais do que uma dermatose por paciente. As alterações cutâneas são frequentes em pacientes em diálise. Mais estudos são necessários para melhor caracterização e manejo destas dermatoses.

  17. Scientific basis of fat requirement for Indians and recent trends in CVD

    Directory of Open Access Journals (Sweden)

    S Ahamed Ibrahim

    2014-12-01

    properties of  unique non glyceride components of some of the  commonly consumed edible oils. From the data generated, the quantity and combination of visible fats, foods to be preferred so as to increase ‘healthy fats', foods to be avoided/restricted to reduce ‘unhealthy fats' have  been worked out. Ensuring optimal intake of fat (quantity and quality throughout life-span may contribute to the widely prevalent nutrition and health problems in India (low birth weight, chronic energy deficiency and diet-related chronic diseases. The rapid increase in prevalence of diet-related chronic diseases including type 2 diabetes, obesity and hypertension worldwide possess an immense public health and medical challenge for the implementation of successful preventive and treatment strategies.  Insulin resistance is an important risk factor for type 2 diabetes and is often associated with other metabolic abnormalities and cardiovascular risk factors. Moreover it is also an important risk factor for cardiovascular diseases (CVD.  Obesity when associated with abdominal adiposity is an important determinant of insulin resistance and represents the most important risk factor for type 2 diabetes and metabolic syndrome.  The explanation for the explosion of the epidemic of chronic diseases involve changes in dietary habits and or / increasing the sedentary life style, since our genetic pool remained stable.  Poor control of the life style risk factors results in metabolic dysregulation, endothelial dysfunction and increased adiposity which in turn together lead to dyslipidemia, hypertension, type 2 diabetes, systemic inflammation, thrombosis and risk of arrhythmia (1.  The ultimate result is sub clinical and then clinically apparent CVD including coronary heart disease (CHD, cardiac arrhythmia, heart failure and stroke.  The best way of preventing chronic diseases is to take a balanced diet that does not provide excess calories along with regular physical activity.  Over the past

  18. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    Science.gov (United States)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    , by the purpose to integrate the carbon nanostructures in the carbon fibers by means of chemical vapor deposition (CVD) method, in order to develop the basic substrate of advanced carbon-based nanocomposite for atomic oxygen protection. The nanostructures grown onto the carbon fibers can be used to create multiscale hybrid carbon nanotube/carbon fiber composites where individual carbon fibers, which are several microns in diameter, are surrounded by nanotubes. The present objective is the setting-up of the CVD parameters for a reliable growth of carbon nanostructures on carbon fiber surface; after that, the results of a preliminary characterization related to atomic oxygen effects testing by means of a ground LEO simulation facility are reported and discussed.

  19. Scientific basis of fat requirement for Indians and recent trends in CVD

    Directory of Open Access Journals (Sweden)

    S Ahamed Ibrahim

    2014-11-01

    properties of  unique non glyceride components of some of the  commonly consumed edible oils. From the data generated, the quantity and combination of visible fats, foods to be preferred so as to increase ‘healthy fats', foods to be avoided/restricted to reduce ‘unhealthy fats' have  been worked out. Ensuring optimal intake of fat (quantity and quality throughout life-span may contribute to the widely prevalent nutrition and health problems in India (low birth weight, chronic energy deficiency and diet-related chronic diseases.The rapid increase in prevalence of diet-related chronic diseases including type 2 diabetes, obesity and hypertension worldwide possess an immense public health and medical challenge for the implementation of successful preventive and treatment strategies.  Insulin resistance is an important risk factor for type 2 diabetes and is often associated with other metabolic abnormalities and cardiovascular risk factors. Moreover it is also an important risk factor for cardiovascular diseases (CVD.  Obesity when associated with abdominal adiposity is an important determinant of insulin resistance and represents the most important risk factor for type 2 diabetes and metabolic syndrome.  The explanation for the explosion of the epidemic of chronic diseases involve changes in dietary habits and or / increasing the sedentary life style, since our genetic pool remained stable.  Poor control of the life style risk factors results in metabolic dysregulation, endothelial dysfunction and increased adiposity which in turn together lead to dyslipidemia, hypertension, type 2 diabetes, systemic inflammation, thrombosis and risk of arrhythmia (1.  The ultimate result is sub clinical and then clinically apparent CVD including coronary heart disease (CHD, cardiac arrhythmia, heart failure and stroke.  The best way of preventing chronic diseases is to take a balanced diet that does not provide excess calories along with regular physical activity.  Over the past

  20. EM International. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    It is the intent of EM International to describe the Office of Environmental Restoration and Waste Management`s (EM`s) various roles and responsibilities within the international community. Cooperative agreements and programs, descriptions of projects and technologies, and synopses of visits to international sites are all highlighted in this semiannual journal. Focus on EM programs in this issue is on international collaboration in vitrification projects. Technology highlights covers: in situ sealing for contaminated sites; and remote sensors for toxic pollutants. Section on profiles of countries includes: Arctic contamination by the former Soviet Union, and EM activities with Germany--cooperative arrangements.

  1. Combined sonochemical/CVD method for preparation of nanostructured carbon-doped TiO{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Rasoulnezhad, Hossein [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Kavei, Ghassem, E-mail: kaveighassem@gmail.com [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Ahmadi, Kamran [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Rahimipour, Mohammad Reza [Ceramic Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of)

    2017-06-30

    Highlights: • Combination of sonochemical and CVD methods for preparation of nanostructured carbon-doped TiO{sub 2} thin film on glass substrate, for the first time. • High transparency, monodispersity and homogeneity of the prepared thin films. • Preparation of the carbon-doped TiO{sub 2} thin films with nanorod and nanosphere morphologies. - Abstract: The present work reports the successful synthesis of the nanostructured carbon-doped TiO{sub 2} thin films on glass substrate by combination of chemical vapor deposition (CVD) and ultrasonic methods, for the first time. In this method the ultrasound waves act as nebulizer for converting of sonochemically prepared TiO{sub 2} sol to the mist particles. These mist particles were thermally decomposed in subsequent CVD chamber at 320 °C to produce the carbon-doped TiO{sub 2} thin films. The obtained thin films were characterized by means of X-ray Diffraction (XRD), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. The results show that the prepared thin films have anatase crystal structure and nanorod morphology, which calcination of them at 800 °C results in the conversion of nanorods to nanoparticles. In addition, the prepared samples have high transparency, monodispersity and homogeneity. The presence of the carbon element in the structure of the thin films causes the narrowing of the band-gap energy of TiO{sub 2} to about 2.8 eV, which results in the improvement of visible light absorption capabilities of the thin film.

  2. Influence of electrodes on the photon energy deposition in CVD-diamond dosimeters studied with the Monte Carlo code PENELOPE

    International Nuclear Information System (INIS)

    Gorka, B; Nilsson, B; Fernandez-Varea, J M; Svensson, R; Brahme, A

    2006-01-01

    A new dosimeter, based on chemical vapour deposited (CVD) diamond as the active detector material, is being developed for dosimetry in radiotherapeutic beams. CVD-diamond is a very interesting material, since its atomic composition is close to that of human tissue and in principle it can be designed to introduce negligible perturbations to the radiation field and the dose distribution in the phantom due to its small size. However, non-tissue-equivalent structural components, such as electrodes, wires and encapsulation, need to be carefully selected as they may induce severe fluence perturbation and angular dependence, resulting in erroneous dose readings. By introducing metallic electrodes on the diamond crystals, interface phenomena between high- and low-atomic-number materials are created. Depending on the direction of the radiation field, an increased or decreased detector signal may be obtained. The small dimensions of the CVD-diamond layer and electrodes (around 100 μm and smaller) imply a higher sensitivity to the lack of charged-particle equilibrium and may cause severe interface phenomena. In the present study, we investigate the variation of energy deposition in the diamond detector for different photon-beam qualities, electrode materials and geometric configurations using the Monte Carlo code PENELOPE. The prototype detector was produced from a 50 μm thick CVD-diamond layer with 0.2 μm thick silver electrodes on both sides. The mean absorbed dose to the detector's active volume was modified in the presence of the electrodes by 1.7%, 2.1%, 1.5%, 0.6% and 0.9% for 1.25 MeV monoenergetic photons, a complete (i.e. shielded) 60 Co photon source spectrum and 6, 18 and 50 MV bremsstrahlung spectra, respectively. The shift in mean absorbed dose increases with increasing atomic number and thickness of the electrodes, and diminishes with increasing thickness of the diamond layer. From a dosimetric point of view, graphite would be an almost perfect electrode

  3. Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

    International Nuclear Information System (INIS)

    Kirchheim, Dennis; Jaritz, Montgomery; Hopmann, Christian; Dahlmann, Rainer; Mitschker, Felix; Awakowicz, Peter; Gebhard, Maximilian; Devi, Anjana; Brochhagen, Markus; Böke, Marc

    2017-01-01

    Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments. (paper)

  4. Effect of surface irradiation during the photo-CVD deposition of a-Si:H thin films. Hikari CVD ho ni yoru amorphous silicon sakuseiji no kiban hikari reiki koka

    Energy Technology Data Exchange (ETDEWEB)

    Tasaka, K.; Doering, H.; Hashimoto, K.; Fujishima, A. (The University of Tokyo, Tokyo (Japan))

    1990-12-06

    This paper shows the impact of the irradiation from an additional light source during the deposition of hydrogenated amorphous silicon by photo-CVD deposition. Using a mercury sensitized photo-CVD process from Disilan (Si {sub 2} H {sub 6}) and hydrogen, silicon was deposited. A 40W low pressure mercury lamp was applied as the light source. A portion of the substrate was in addition irradiated using an Xg-He lamp through a thermal filter. Irradiation of the substrate using only Xg-He lamp produced no deposition, since this light has a wavelength which is too long to produce the SiH {sub 3}-radicals needed for Si deposition. The additional Xg-He light source was discovered to cause an increased thickness of deposited a-Si:H film and a transmission of the band structure. The reasons of these are considered that the influence of irradiation is not limited to film thickness, but that irradiation also impacts the composition of the a-Si:H film so as to cause a reduction in the hydrogen content. 10 figs., 1 tab.

  5. Microsatellite Loci in the Gypsophyte <em>Lepidium subulatum em>(Brassicaceae, and Transferability to Other <em>Lepidieae>

    Directory of Open Access Journals (Sweden)

    José Gabriel Segarra-Moragues

    2012-09-01

    Full Text Available Polymorphic microsatellite markers were developed for the Ibero-North African, strict gypsophyte <em>Lepidium subulatumem> to unravel the effects of habitat fragmentation in levels of genetic diversity, genetic structure and gene flow among its populations. Using 454 pyrosequencing 12 microsatellite loci including di- and tri-nucleotide repeats were characterized in <em>L. subulatumem>. They amplified a total of 80 alleles (2–12 alleles per locus in a sample of 35 individuals of <em>L. subulatumem>, showing relatively high levels of genetic diversity, <em>H>O = 0.645, <em>H>E = 0.627. Cross-species transferability of all 12 loci was successful for the Iberian endemics <em>Lepidium cardaminesem>, <em>Lepidium stylatumem>, and the widespread, <em>Lepidium graminifoliumem> and one species each of two related genera, <em>Cardaria drabaem> and <em>Coronopus didymusem>. These microsatellite primers will be useful to investigate genetic diversity, population structure and to address conservation genetics in species of <em>Lepidium>.

  6. Design of Electrically Conductive Structural Composites by Modulating Aligned CVD-Grown Carbon Nanotube Length on Glass Fibers.

    Science.gov (United States)

    He, Delong; Fan, Benhui; Zhao, Hang; Lu, Xiaoxin; Yang, Minhao; Liu, Yu; Bai, Jinbo

    2017-01-25

    Function-integration in glass fiber (GF) reinforced polymer composites is highly desired for developing lightweight structures and devices with improved performance and structural health monitoring. In this study, homogeneously aligned carbon nanotube (CNT) shell was in situ grafted on GF by chemical vapor deposition (CVD). It was demonstrated that the CNT shell thickness and weight fraction can be modulated by controlling the CVD conditions. The obtained hierarchical CNTs-GF/epoxy composites show highly improved electrical conductivity and thermo-mechanical and flexural properties. The composite through-plane and in-plane electrical conductivities increase from a quasi-isolator value to ∼3.5 and 100 S/m, respectively, when the weight fraction of CNTs grafted on GF fabric varies from 0% to 7%, respectively. Meanwhile, the composite storage modulus and flexural modulus and strength improve as high as 12%, 21%, and 26%, respectively, with 100% retention of the glass transition temperature. The reinforcing mechanisms are investigated by analyzing the composite microstructure and the interfacial adhesion and wetting properties of CNTs-GF hybrids. Moreover, the specific damage-related resistance variation characteristics could be employed to in situ monitor the structural health state of the composites. The outstanding electrical and structural properties of the CNTs-GF composites were due to the specific interfacial and interphase structures created by homogeneously grafting aligned CNTs on each GF of the fabric.

  7. Urchin-like artificial gallium oxide nanowires grown by a novel MOCVD/CVD-based route for random laser application

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Ronaldo P. de [Programa de Pós-Graduação em Ciências de Materiais, Universidade Federal de Pernambuco, Recife (Brazil); Colégio Militar do Recife, Exército Brasileiro, Recife PE 50730-120 (Brazil); Oliveira, Nathalia Talita C. [Programa de Pós-Graduação em Ciências de Materiais, Universidade Federal de Pernambuco, Recife (Brazil); Dominguez, Christian Tolentino; Gomes, Anderson S. L.; Araújo, Cid B. de [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife (Brazil); Falcão, Eduardo H. L.; Alves, Severino; Luz, Leonis L. da [Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50670-901 Recife (Brazil); Chassagnon, Remi [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47870, 21078 Dijon Cedex (France); Sacilotti, Marco [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife (Brazil); Nanoform Group, Laboratoire Interdisciplinaire Carnot de Bourgogne, Université de Bourgogne, Dijon (France)

    2016-04-28

    A novel procedure based on a two-step method was developed to obtain β-Ga{sub 2}O{sub 3} nanowires by the chemical vapor deposition (CVD) method. The first step consists in the gallium micro-spheres growth inside a metal-organic chemical vapor deposition environment, using an organometallic precursor. Nanoscale spheres covering the microspheres were obtained. The second step involves the CVD oxidization of the gallium micro-spheres, which allow the formation of β-Ga{sub 2}O{sub 3} nanowires on the micro-sphere surface, with the final result being a nanostructure mimicking nature's sea urchin morphology. The grown nanomaterial is characterized by several techniques, including X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, and photoluminescence. A discussion about the growth mechanism and the optical properties of the β-Ga{sub 2}O{sub 3} material is presented considering its unknown true bandgap value (extending from 4.4 to 5.68 eV). As an application, the scattering properties of the nanomaterial are exploited to demonstrate random laser emission (around 570 nm) when it is permeated with a laser dye liquid solution.

  8. An optical emission spectroscopy study of the plasma generated in the DC HF CVD nucleation of diamond

    Energy Technology Data Exchange (ETDEWEB)

    Larijani, M.M. [Nuclear Research Centre for Agriculture and Medicine, AEOI, P.O. Box 31485-498, Karaj (Iran, Islamic Republic of)]. E-mail: mmojtahedzadeh@nrcam.org; Le Normand, F. [Groupe Surfaces-Interfaces, IPCMS, UMR 7504 CNRS, BP 20, 67037 Strasbourg Cedex 2 (France); Cregut, O. [Groupe Surfaces-Interfaces, IPCMS, UMR 7504 CNRS, BP 20, 67037 Strasbourg Cedex 2 (France)

    2007-02-15

    Optical emission spectroscopy (OES) was used to study the plasma generated by the activation of the gas phase CH{sub 4} + H{sub 2} both by hot filaments and by a plasma discharge (DC HF CVD) during the nucleation of CVD diamond. The effects of nucleation parameters, such as methane concentration and extraction potential, on the plasma chemistry near the surface were investigated. The density of the diamond nucleation and the quality of the diamond films were studied by scanning electron microscopy (SEM) and Raman scattering, respectively. The OES results showed that the methane concentration influenced strongly the intensity ratio of H{sub {beta}}-H{sub {alpha}} implying an increase of electron mean energy, as well as CH, CH{sup +}, C{sub 2}. A correlation between the relative increase of CH{sup +} and the diamond nucleation density was found, conversely the increase of C{sub 2} contributed to the introduction of defects in the diamond nuclei.

  9. Efficient etching-free transfer of high quality, large-area CVD grown graphene onto polyvinyl alcohol films

    International Nuclear Information System (INIS)

    Marta, Bogdan; Leordean, Cosmin; Istvan, Todor; Botiz, Ioan; Astilean, Simion

    2016-01-01

    Graphical abstract: - Highlights: • One-step dry transfer method of CVD grown graphene onto PVA films. • Investigation of graphene quality and number of layers of the synthesized and transferred graphene. • Promising scalability and good quality of transferred graphene onto flexible transparent polymers. - Abstract: Graphene transfer is a procedure of paramount importance for the production of graphene-based electronic devices. The transfer procedure can affect the electronic properties of the transferred graphene and can be detrimental for possible applications both due to procedure induced defects which can appear and due to scalability of the method. Hence, it is important to investigate new transfer methods for graphene that are less time consuming and show great promise. In the present study we propose an efficient, etching-free transfer method that consists in applying a thin polyvinyl alcohol layer on top of the CVD grown graphene on Cu and then peeling-off the graphene onto the polyvinyl alcohol film. We investigate the quality of the transferred graphene before and after the transfer, using Raman spectroscopy and imaging as well as optical and atomic force microscopy techniques. This simple transfer method is scalable and can lead to complete transfer of graphene onto flexible and transparent polymer support films without affecting the quality of the graphene during the transfer procedure.

  10. Immobilization of glucoamylase on ceramic membrane surfaces modified with a new method of treatment utilizing SPCP-CVD.

    Science.gov (United States)

    Ida; Matsuyama; Yamamoto

    2000-07-01

    Glucoamylase, as a model enzyme, was immobilized on a ceramic membrane modified by surface corona discharge induced plasma chemical process-chemical vapor deposition (SPCP-CVD). Characterizations of the immobilized enzyme were then discussed. Three kinds of ceramic membranes with different amounts of amino groups on the surface were prepared utilizing the SPCP-CVD method. Each with 1-time, 3-times and 5-times surface modification treatments and used for supports in glucoamylase immobilization. The amount of immobilized glucoamylase increased with the increase in the number of surface modification treatments and saturated to a certain maximum value estimated by a two-dimensional random packing. The operational stability of the immobilized glucoamylase also increased with the increase in the number of the surface treatment. It was almost the same as the conventional method, while the activity of immobilized enzyme was higher. The results indicated the possibility of designing the performance of the immobilized enzyme by controlling the amount of amino groups. The above results showed that the completely new surface modification method using SPCP was effective in modifying ceramic membranes for enzyme immobilization.

  11. Large-scale synthesis of NbS2 nanosheets with controlled orientation on graphene by ambient pressure CVD.

    Science.gov (United States)

    Ge, Wanyin; Kawahara, Kenji; Tsuji, Masaharu; Ago, Hiroki

    2013-07-07

    We report ambient pressure chemical vapor deposition (CVD) growth of single-crystalline NbS2 nanosheets with controlled orientation. On Si and SiO2 substrates, NbS2 nanosheets grow almost perpendicular to the substrate surface. However, when we apply transferred CVD graphene on SiO2 as a substrate, NbS2 sheets grow laterally lying on the graphene. The NbS2 sheets show the triangular and hexagonal shapes with a thickness of about 20-200 nm and several micrometres in the lateral dimension. Analyses based on X-ray diffraction and Raman spectroscopy indicate that the NbS2 nanosheets are single crystalline 3R-type with a rhombohedral structure of R3m space group. Our findings on the formation of highly aligned NbS2 nanosheets on graphene give new insight into the formation mechanism of NbS2 and would contribute to the templated growth of various layered materials.

  12. High-order Stokes and anti-Stokes Raman generation in monoisotopic CVD {sup 12}C-diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Lux, Oliver; Rhee, Hanjo; Eichler, Hans J. [Institute of Optics and Atomic Physics, Technische Universitaet Berlin (Germany); Ralchenko, Victor G.; Bolshakov, Andrey P. [General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Shirakawa, Akira; Yoneda, Hitoki [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan)

    2016-06-15

    We determined, for the first time, the room temperature phonon energy related to the F{sub 2g} vibration mode (ω{sub SRS(12C)} ∝ 1333.2 cm{sup -1}) in a mono-crystalline single-isotope CVD {sup 12}C-diamond crystal by means of stimulated Raman scattering (SRS) spectroscopy. Picosecond one-micron excitation using a Nd{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}-laser generates a nearly two-octave spanning SRS frequency comb (∝12000 cm{sup -1}) consisting of higher-order Stokes and anti-Stokes components. The spacing of the spectral lines was found to differ by Δω{sub SRS} ∝ 0.9 cm{sup -1} from the comb spacing (ω{sub SRS(natC)} ∝ 1332.3 cm{sup -1}) when pumping a conventional CVD diamond crystal with a natural composition of the two stable carbon isotopes {sup 12}C (98.93%) and {sup 13}C (1.07%). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Unravelling merging behaviors and electrostatic properties of CVD-grown monolayer MoS{sub 2} domains

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Song; Yang, Bingchu, E-mail: bingchuyang@csu.edu.cn [College of Physics and Electronics, Institute of Super Microstructure and Ultrafast Process in Advanced Materials, Central South University, 605 South Lushan Road, Changsha 410012 (China); Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha 410012 (China); Gao, Yongli [College of Physics and Electronics, Institute of Super Microstructure and Ultrafast Process in Advanced Materials, Central South University, 605 South Lushan Road, Changsha 410012 (China); Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha 410012 (China); Department of Physics and Astronomy, University of Rochester, Rochester, New York 14534 (United States)

    2016-08-28

    The presence of grain boundaries is inevitable for chemical vapor deposition (CVD)-grown MoS{sub 2} domains owing to various merging behaviors, which greatly limits its potential applications in novel electronic and optoelectronic devices. It is therefore of great significance to unravel the merging behaviors of the synthesized polygon shape MoS{sub 2} domains. Here we provide systematic investigations of merging behaviors and electrostatic properties of CVD-grown polycrystalline MoS{sub 2} crystals by multiple means. Morphological results exhibit various polygon shape features, ascribed to polycrystalline crystals merged with triangle shape MoS{sub 2} single crystals. The thickness of triangle and polygon shape MoS{sub 2} crystals is identical manifested by Raman intensity and peak position mappings. Three merging behaviors are proposed to illustrate the formation mechanisms of observed various polygon shaped MoS{sub 2} crystals. The combined photoemission electron microscopy and kelvin probe force microscopy results reveal that the surface potential of perfect merged crystals is identical, which has an important implication for fabricating MoS{sub 2}-based devices.

  14. Barrier Performance of CVD Graphene Films Using a Facile P3HT Thin Film Optical Transmission Test

    Directory of Open Access Journals (Sweden)

    Srinivasa Kartik Nemani

    2018-01-01

    Full Text Available The barrier performance of CVD graphene films was determined using a poly(3-hexylthiophene (P3HT thin film optical transmission test. P3HT is a semiconducting polymer that photo-oxidatively degrades upon exposure to oxygen and light. The polymer is stable under ambient conditions and indoor lighting, enabling P3HT films to be deposited and encapsulated in air. P3HT’s stability under ambient conditions makes it desirable for an initial evaluation of barrier materials as a complimentary screening method in combination with conventional barrier tests. The P3HT test was used to demonstrate improved barrier performance for polymer substrates after addition of CVD graphene films. A layer-by-layer transfer method was utilized to enhance the barrier performance of monolayer graphene. Another set of absorption measurements were conducted to demonstrate the barrier performance of graphene and the degradation mechanism of graphene/P3HT over multiple wavelengths from 400 to 800 nm. The absorption spectra for graphene/polymer composite were simulated by solving Fresnel equations. The simulation results were found to be in good agreement with the measured absorption spectra. The P3HT degradation results qualitatively indicate the potential of graphene films as a possible candidate for medium performance barriers.

  15. One-dimensional surface-imprinted polymeric nanotubes for specific biorecognition by initiated chemical vapor deposition (iCVD).

    Science.gov (United States)

    Ince, Gozde Ozaydin; Armagan, Efe; Erdogan, Hakan; Buyukserin, Fatih; Uzun, Lokman; Demirel, Gokhan

    2013-07-24

    Molecular imprinting is a powerful, generic, and cost-effective technique; however, challenges still remain related to the fabrication and development of these systems involving nonhomogeneous binding sites, insufficient template removing, incompatibility with aqueous media, low rebinding capacity, and slow mass transfer. The vapor-phase deposition of polymers is a unique technique because of the conformal nature of coating and offers new possibilities in a number of applications including sensors, microfluidics, coating, and bioaffinity platforms. Herein, we demonstrated a simple but versatile concept to generate one-dimensional surface-imprinted polymeric nanotubes within anodic aluminum oxide (AAO) membranes based on initiated chemical vapor deposition (iCVD) technique for biorecognition of immunoglobulin G (IgG). It is reported that the fabricated surface-imprinted nanotubes showed high binding capacity and significant specific recognition ability toward target molecules compared with the nonimprinted forms. Given its simplicity and universality, the iCVD method can offer new possibilities in the field of molecular imprinting.

  16. Efficient etching-free transfer of high quality, large-area CVD grown graphene onto polyvinyl alcohol films

    Energy Technology Data Exchange (ETDEWEB)

    Marta, Bogdan; Leordean, Cosmin [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Istvan, Todor [Babes-Bolyai University, Faculty of Physics, Biomolecular Physics Department, M Kogalniceanu Str. 1, Cluj-Napoca 400084 (Romania); Botiz, Ioan [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Astilean, Simion, E-mail: simion.astilean@phys.ubbcluj.ro [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Babes-Bolyai University, Faculty of Physics, Biomolecular Physics Department, M Kogalniceanu Str. 1, Cluj-Napoca 400084 (Romania)

    2016-02-15

    Graphical abstract: - Highlights: • One-step dry transfer method of CVD grown graphene onto PVA films. • Investigation of graphene quality and number of layers of the synthesized and transferred graphene. • Promising scalability and good quality of transferred graphene onto flexible transparent polymers. - Abstract: Graphene transfer is a procedure of paramount importance for the production of graphene-based electronic devices. The transfer procedure can affect the electronic properties of the transferred graphene and can be detrimental for possible applications both due to procedure induced defects which can appear and due to scalability of the method. Hence, it is important to investigate new transfer methods for graphene that are less time consuming and show great promise. In the present study we propose an efficient, etching-free transfer method that consists in applying a thin polyvinyl alcohol layer on top of the CVD grown graphene on Cu and then peeling-off the graphene onto the polyvinyl alcohol film. We investigate the quality of the transferred graphene before and after the transfer, using Raman spectroscopy and imaging as well as optical and atomic force microscopy techniques. This simple transfer method is scalable and can lead to complete transfer of graphene onto flexible and transparent polymer support films without affecting the quality of the graphene during the transfer procedure.

  17. Multilayer CVD Diamond Coatings in the Machining of an Al6061-15 Vol % Al2O3 Composite

    Directory of Open Access Journals (Sweden)

    Mohammadmehdi Shabani

    2017-10-01

    Full Text Available Ceramic cutting inserts coated with ten-fold alternating micro- and nanocrystalline diamond (MCD/NCD layers grown by hot filament chemical vapor deposition (CVD were tested in the machining of an Al based metallic matrix composite (MMC containing 15 vol % Al2O3 particles. Inserts with total coating thicknesses of approximately 12 µm and 24 µm were produced and used in turning: cutting speed (v of 250 to 1000 m·min−1; depth of cut (DOC from 0.5 to 3 mm and feed (f between 0.1 and 0.4 mm·rev−1. The main cutting force increases linearly with DOC (ca. 294 N per mm and with feed (ca. 640 N per mm·rev−1. The thicker coatings work within the following limits: DOC up to 1.5 mm and maximum speeds of 750 m·min−1 for feeds up to 0.4 mm·rev−1. Flank wear is predominant but crater wear is also observed due to the negative tool normal rake. Layer-by-layer wear of the tool rake, and not total delamination from the substrate, evidenced one of the advantages of using a multilayer design. The MCD/NCD multilayer diamond coated indexable inserts have longer tool life than most CVD diamond systems and behave as well as most polycrystalline diamond (PCD tools.

  18. New materials for advanced lithium battery. Especially on plasma-assisted CVD of TiS sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Kikkawa, Shin' ichi [Osaka Univ. (Japan)

    1989-03-15

    Intercalation can be applied to cathode reaction of rechargeable battery. Three kinds of candidate materials, TiS{sub 2}, NbS{sub 3} and alkali transition metal dioxides such as LiCoO{sub 2} were studied as the battery cathode. TiS{sub 2} is closest to a practical usage. Lithium ion has to diffuse in the TiS{sub 2} crystal lattice during the intercalation. Large surface area is necessary to obtain high current density. Preferred orientation of the crystallite is also required in its film formation to further enhance its current density. CVD reactor was used to obtain TiS{sub 2} fine powder and its thin film. Black fine power was obtained on a thin film deposited on a glass substrate. The powder was obtained in high yield under a pressure of 120 Pa at the electrode center where the plasma density was high. In conclusion, TiS{sub 2} fine power with submicron diameter and also highly preferred oriented TiS{sub 2} thin film were obtained using plasma-CVD. 21 refs., 8 figs.

  19. CVD growth of large-area and high-quality HfS2 nanoforest on diverse substrates

    Science.gov (United States)

    Zheng, Binjie; Wang, Zegao; Qi, Fei; Wang, Xinqiang; Yu, Bo; Zhang, Wanli; Chen, Yuanfu

    2018-03-01

    Two-dimensional layered transition metal dichalcogenides (TMDs) have attracted burgeoning attention due to their various properties and wide potential applications. As a new TMD, hafnium disulfide (HfS2) is theoretically predicted to have better electrical performance than widely studied MoS2. The experimental researches also confirmed the extraordinary feature in electronics and optoelectronics. However, the maximal device performance may not be achieved due to its own limitation of planar structure and challenge of transfer without contamination. Here, through the chemical vapor deposition (CVD) technique, inch-size HfS2 nanoforest has been directly grown on diverse objective substrates covering insulating, semiconducting and conducting substrates. This direct CVD growth without conventional transfer process avoids contamination and degradation in quality, suggesting its promising and wide applications in high-quality and multifarious devices. It is noted that all the HfS2 nanoforests grown on diverse substrates are constructed with vertically aligned few-layered HfS2 nanosheets with high crystalline quality and edge orientation. Moreover, due to its unique structure, the HfS2 nanoforest owns abundant exposed edge sites and large active surface area, which is essential to apply in high-performance catalyst, sensor, and energy storage or field emitter.

  20. Marketing em moda

    OpenAIRE

    Leães, Sabrina Durgante

    2008-01-01

    Dissertação de mestrado em Design e Marketing O actual estado do Marketing em Moda é uma das questões ainda complexa com que se debate a sociedade global. As questões do Marketing em Moda percorrem alguns aspectos fundamentais tais como as constantes mutações do meio envolvente, a forma de como é percebida e comunicada a identidade das marcas de moda, em busca da melhor forma de segmentar o mercado e definir o seu posicionamento, bem como a reacção ao produto de moda do consumidor final. ...