WorldWideScience

Sample records for sio gas created

  1. The Role of SiO2 Gas in the Operation of Anti-Corrosion Coating Produced by PVD

    Directory of Open Access Journals (Sweden)

    Meysam Zarchi

    2015-09-01

    Full Text Available This study examined theSiO2 gas present in the coatings used in corrosion industry.These layers have been created by physical vapor deposition (PVD, with an appropriate performance. Sublimation of SiO2is used to protect PVD aluminum flakes from water corrosionand to generate highly porous SiO2 flakes with holes in the nanometer range. SiOx/Al/SiOx sandwiches were made as well as Ag loaded porous SiO2 as antimicrobial filler.

  2. High refractive index modification of SiO2 created by femtosecond laser nanostructuring

    International Nuclear Information System (INIS)

    Barillot, T; Grojo, D; Gertsvolf, M; Rayner, D M; Corkum, P B; Lei, S

    2010-01-01

    By comparing simulations with experiment, we show that the effective refractive index of fused SiO 2 can be locally reduced by (1.8 ± 0.2)% by femtosecond laser nanostructuring. We create a microlens of material containing a planar array of nanocracks embedded inside fused silica and probe how it refracts or absorbs light as a function of pulse energy. The self-generated microlens lowers the peak light intensity by deflecting the light around the focus. We obtain the refractive index by simulating the beam transport using the 3D wave equation in conjunction with the measured dimensions of the modified material.

  3. To create a gas culture, national purpose

    International Nuclear Information System (INIS)

    Anon

    1998-01-01

    In 1986 it began to speak for the first time of the gas like substitute of the energy in the capital, to toast this way a better energetic option. The business of the gas in Colombia has a great expansion potential, judging by the millionaire transactions that have been carried out recently, in which have participated with signal interest investors of all the continents and it is that the future tendency is the substituting the electric devices for gas devices, at least in that that to cooking of foods and heating of water refers, given the economic and environmental benefits that it represents the overcrowding of the consumption of combustible gases (natural gas and liquefied gas of the petroleum). The economic importance of the investment in the plan of overcrowding of the natural gas in Colombia, represents a very important aspect proposed by the government and of all the actors involved inside the gas industry and it is the one of benefiting economically to the whole community, through the social investment, advanced in each region to or release and wide of the whole country. This promissory panorama for the nascent Colombian gas industry, supported by the discoveries of gas carried out in the decade of the 90, in increasing the reserves of natural gas, to build a great gas pipeline and urban nets, to carry out complementary works and of conversion to gas, to supply thermoelectric that will generate near additional 1500 MW of energy, it also seeks to benefit with the domiciliary gas service, in next four years to more than three million homes distributed in for the less 300 municipalities of the national geography

  4. CONSTRAINTS ON THE PRESENCE OF SiO GAS IN THE DEBRIS DISK OF HD 172555

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T. L. [United States Naval Research Laboratory, Washington, DC 20375 (United States); Nilsson, R. [Astrophysics Department, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Chen, C. H.; Moerchen, M.; Banzatti, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21212 (United States); Lisse, C. M. [Space Exploration Sector, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, 20723 (United States); Käufl, H.-U., E-mail: thomaswilson1b@gmail.com [European Southern Observatory, K-Schwarzschild-str. 2, Garching, D-85748 (Germany)

    2016-08-01

    We have carried out two sets of observations to quantify the properties of SiO gas in the unusual HD 172555 debris disk: (1) a search for the J = 8–7 rotational transition from the vibrational ground state, carried out with the Atacama Pathfinder EXperiment (APEX) submillimeter telescope and heterodyne receiver at 863 μ m and (2) a search at 8.3 μ m for the P(17) ro-vibrational transition of gas phase SiO, carried out with the Very Large Telescope (VLT)/VISIR with a resolution, λ /Δ λ , of 30,000. The APEX measurement resulted in a 3.3 σ detection of an interstellar feature, but only an upper limit to emission at the radial velocity and line width expected from HD 172555. The VLT/VISIR result was also an upper limit. These were used to provide limits for the abundance of gas phase SiO for a range of temperatures. The upper limit from our APEX detection, assuming an 8000 K primary star photospheric excitation, falls more than an order of magnitude below the self-shielding stability threshold derived by Johnson et al. (2012). Our results thus favor a solid-state origin for the 8.3 μ m feature seen in the Spitzer IRS spectrum of the circumstellar excess emission and the production of circumstellar O i and Si i by SiO UV photolysis. The implications of these estimates are explored in the framework of models of the HD 172555 circumstellar disk.

  5. Effect of sweep gas chemistry on vaporization of Li4SiO4

    International Nuclear Information System (INIS)

    Yamawaki, M.; Yamaguchi, K.

    1995-01-01

    Gas/solid equilibria in the system Li 4 SiO 4 -D 2 -D 2 O were studied by means of Knudsen effusion mass spectrometry. A Knudsen effusion mass spectrometer was modified to enable studies of reactions of hydrogen and/or water vapor with ceramic breeder materials. A gas inlet system was constructed to allow the introduction of gases into a platinum Knudsen cell, from which the equilibrated gaseous reaction products effuse. From the experimental results, it has been deduced that the equilibrium constants of vaporization reactions differ correspondingly to the nonstoichiometry of lithium orthosilicate. ((orig.))

  6. A VUV photoionization measurement and ab-initio calculation of the ionization energy of gas phase SiO2

    Energy Technology Data Exchange (ETDEWEB)

    Kostko, Oleg; Ahmed, Musahid; Metz, Ricardo B.

    2008-12-05

    In this work we report on the detection and vacuum-ultraviolet (VUV) photoionization of gas phase SiO2 generated in situ via laser ablation of silicon in a CO2 molecular beam. The resulting species are investigated by single photon ionization with tunable VUV synchrotron radiation and mass analyzed using reflectron mass spectrometry. Photoionization efficiency (PIE) curves are recorded for SiO and SiO2 and ionization energy estimates are revealed from such measurements. A state-to-state ionizationenergy of 12.60 (+-0.05) eV is recorded by fitting two prominent peaks in the PIE curve for the following process: 1SUM O-Si-O --> 2PRODg [O-Si-O]+. Electronic structure calculations aid in the interpretation of the photoionization process and allow for identification of the symmetric stretch of 2PRODg [O-Si-O]+ which is observed in the PIE spectrum to be 0.11 eV (890 cm-1) above the ground state of the cation and agrees with the 892 cm-1 symmetric stretch frequency calculated at the CCSD(T)/aug-cc-pVTZ level.

  7. Highly selective SiO2 etching over Si3N4 using a cyclic process with BCl3 and fluorocarbon gas chemistries

    Science.gov (United States)

    Matsui, Miyako; Kuwahara, Kenichi

    2018-06-01

    A cyclic process for highly selective SiO2 etching with atomic-scale precision over Si3N4 was developed by using BCl3 and fluorocarbon gas chemistries. This process consists of two alternately performed steps: a deposition step using BCl3 mixed-gas plasma and an etching step using CF4/Ar mixed-gas plasma. The mechanism of the cyclic process was investigated by analyzing the surface chemistry at each step. BCl x layers formed on both SiO2 and Si3N4 surfaces in the deposition step. Early in the etching step, the deposited BCl x layers reacted with CF x radicals by forming CCl x and BF x . Then, fluorocarbon films were deposited on both surfaces in the etching step. We found that the BCl x layers formed in the deposition step enhanced the formation of the fluorocarbon films in the CF4 plasma etching step. In addition, because F radicals that radiated from the CF4 plasma reacted with B atoms while passing through the BCl x layers, the BCl x layers protected the Si3N4 surface from F-radical etching. The deposited layers, which contained the BCl x , CCl x , and CF x components, became thinner on SiO2 than on Si3N4, which promoted the ion-assisted etching of SiO2. This is because the BCl x component had a high reactivity with SiO2, and the CF x component was consumed by the etching reaction with SiO2.

  8. Creating and maintaining a gas cap in tar sands formations

    Science.gov (United States)

    Vinegar, Harold J.; Karanikas, John Michael; Dinkoruk, Deniz Sumnu; Wellington, Scott Lee

    2010-03-16

    Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

  9. A new cataluminescence gas sensor based on SiO2 nanotubes fabricated using carbon nanotube templates.

    Science.gov (United States)

    Wang, Yali; Cao, Xiaoan; Li, Jinwen; Chen, Nan

    2011-05-15

    In the present work, two morphologies of SiO(2) nanomaterials (SiO(2) nanotubes and nanoparticles) have been successfully synthesized in supercritical fluids (SCFs). The cataluminescence (CTL) features of the two SiO(2) nanomaterials to some common harmful gases were compared, and the results showed that SiO(2) nanotubes had better CTL sensing characteristic to some common harmful gases. The SiO(2) nanotubes not only had uniform size and shape with a high specific surface area, but also exhibited superior sensitivity and selectivity to ethyl acetate vapor. Using the SiO(2) nanotubes as sensing material, a CTL sensor for ethyl acetate vapor was developed. The proposed sensor showed high sensitivity and specificity to ethyl acetate at optimal temperature of 293°C, a wavelength of 425 nm and a flow rate of 345 mL/min. With a detection limit of 0.85 ppm, the linear range of CTL intensity versus concentrations of ethyl acetate vapor was 2.0-2000 ppm. None or only very low levels of interference were observed while the foreign substances such as acetone, acetaldehyde, acetic acid, formaldehyde, ammonia, ethanol, benzene and methanol were passing through the sensor. This method allows rapid determination of gaseous ethyl acetate at workshop. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Russian Gas for Europe. Creating Access and Choice. Underpinning Russia's gas export strategy with Gazprom's infrastructure investments

    International Nuclear Information System (INIS)

    Smeenk, T.

    2010-07-01

    This study deals with Gazprom's investment strategy regarding Russia's gas exports and export market behaviour, with a focus on European infrastructure projects, in a the geopolitical context. Because of its large gas reserves, Russia is well-positioned to take advantage of gas exports even as it faces possible competition from other gas suppliers and uncertain gas demand. Gas export earnings are an important source of income for Russia. As a government-controlled firm, Gazprom depends to a large extent on Europe for its hard-currency income. For Russia and Gazprom, the stream of income from gas exports and its expansion are economically vital. In this regard, gas export infrastructures such as Nord and South Stream could act as important instruments to expand Gazprom's market share in current markets and in growth markets. This study uses a real-option game model to assess the overall value of gas infrastructures in the face of demand uncertainties and potential competition. The result of this approach illustrates the strategic-economic character of Gazprom's infrastructure investments in possibly creating a first-mover's advantage. Yet, the model is of a highly stylised nature. Therefore, other aspects should be taken into account in assessing gas infrastructure investments. Besides the goal of possibly expanding Gazprom's market share, infrastructure investments could serve to mitigate overall transit risks. However, Gazprom's organisational constraints in realising gas infrastructures could put into question the rationale of such investments. In addition, Gazprom's position as well as that of Russian gas may be pressured by European (regulatory) policy in favour of alternative gas and other energy sources. The desired market outcomes for Gazprom have an impact on the prioritisation of Russian investments in the gas value chain.

  11. A preliminary study on the etching behavior of SiO sub 2 aerogel film with CHF sub 3 gas

    CERN Document Server

    Wang, S J; Yeom, G Y

    1998-01-01

    Etching behavior of SiO sub 2 aerogel film has been investigated in order to examine the feasibility of its application to an interlevel dielectric material. Low dielectric property of SiO sub 2 aerogel film is simply originated from its highly porous structure, but interconnected particles are covered with surface chemical bondings (-OH, -OC sub 2 H sub 5 , etc). Etching experiments have been performed with high density inductively coupled CHF sub 3 plasma. The effects of porous structure and surface chemical bondings on the etching of SiO sub 2 aerogel film have been analyzed. The changes of surface morphology were observed using scanning electron microscopy. X-ray photoelectron spectroscopic analyses revealed compositions and chemical bonding states of reaction layer. From the analyses, 3-dimensional etching was not feasible macroscopically in SiO sub 2 aerogel film even with its porous nature because network structure was maintained through the etching process. Internal surface chemicals seemed to act an ...

  12. Temperature-compensated Love wave based gas sensor on waveguide structure of SiO2/36° YX LiTaO3

    International Nuclear Information System (INIS)

    Wang, Wen; Xie, Xiao; Chen, Gui; Liu, Jiuling; He, Shitang

    2015-01-01

    A temperature-compensated Love wave device was proposed for gas sensing utilizing a waveguide structure of SiO 2 /36° YX LiTaO 3 . Significant improvement in the temperature stability of the hybrid Love wave device was implemented by varying the guiding layer thickness. The optimal values yielding low cross-sensitivity to temperature and high mass sensitivity in gas sorption were determined theoretically by solving the coupled electromechanical field equation in layered media. The theoretical analysis was confirmed experimentally in dimethylmethylphosphonate (DMMP) detection by using a fluoroalcoholpolysiloxane (SXFA) coated Love wave sensor. The experimental results indicate that better sensitivity and excellent temperature stability were obtained from the developed Love wave gas sensor over the Rayleigh surface acoustic wave (R-SAW) sensors. (paper)

  13. Analysis of thermal detrapping of holes created by electron irradiation in high purity amorphous SiO_2 using the induced and secondary current measurements

    International Nuclear Information System (INIS)

    Said, K.; Moya, G.; Si Ahmed, A.; Damamme, G.; Kallel, A.

    2016-01-01

    Graphical abstract: - Highlights: • Positive charging of high purity amorphous SiO_2 achieved by electron irradiation in a specially equipped scanning electron microscope. • Quantity of detrapped holes evaluated via measurements of induced and secondary electron currents. • Study of isothermal detrapping for different temperatures (300–663 K). • Analysis of the hole detrapping via a first order kinetics. • Evaluation of the hole detrapping parameters (activation energy and frequency factor). - Abstract: Isothermal detrapping of holes after electron irradiation (using a SEM) in high purity amorphous SiO_2 is evaluated at different temperatures (in the range 300–663 K) by means of the induced and secondary current measurements. In order to single out the hole detrapping, the specific charging conditions (1 keV defocused electron beam of low density) leading to positive charging are adopted. The thermal detrapping, which stems from a single trap, begins at 523 K and is completed at 663 K. After annealing in air at 973 K during 48 h, two detrapping stages are revealed: the former is connected with an additional shallow trap, while the latter requires temperatures above 663 K for a complete detrapping. The first order kinetics describes reasonably well the detrapping process. The frequency factors (near 10"1"0 s"−"1) and the activation energies (about 1.6 eV) deduced from this analysis could be assigned, respectively, to the relaxation connected to detrapping and to the trap energy level of the charged oxygen vacancy.

  14. Use of nuclear explosions to create gas condensate storage in the USSR. LLL Treaty Verification Program

    International Nuclear Information System (INIS)

    Borg, I.Y.

    1982-01-01

    The Soviet Union has described industrial use of nuclear explosions to produce underground hydrocarbon storage. To examples are in the giant Orenburg gas condensate field. There is good reason to believe that three additional cavities were created in bedded salt in the yet to be fully developed giant Astrakhan gas condensate field in the region of the lower Volga. Although contrary to usual western practice, the cavities are believed to be used to store H 2 S-rich, unstable gas condensate prior to processing in the main gas plants located tens of kilometers from the producing fields. Detonations at Orenburg and Astrakhan preceded plant construction. The use of nuclear explosions at several sites to create underground storage of highly corrosive liquid hydrocarbons suggests that the Soviets consider this time and cost effective. The possible benefits from such a plan include degasification and stabilization of the condensate before final processing, providing storage of condensate during periods of abnormally high natural gas production or during periods when condensate but not gas processing facilities are undergoing maintenance. Judging from information provided by Soviet specialists, the individual cavities have a maximum capacity on the order of 50,000 m 3

  15. Evaluation of forward sales and options created through natural gas storage

    International Nuclear Information System (INIS)

    Salahor, G.S.; Laughton, D.G.

    1994-01-01

    The deregulation of natural gas markets in North America has resulted in greater quantities of gas being sold under indexed price agreements. As this is occurring, natural gas storage facilities are being developed and opened up for the use of natural gas producers and marketers. While natural gas spot prices continue to exhibit some strong seasonality reflecting higher demand peak in winter, traded futures contract prices tend to discount the expected market price. The elements which contribute to this differential are examined and some of the possible opportunities for the use of gas storage in tandem with other risk management instruments are demonstrated. The specific scenario to be evaluated takes the viewpoint of a natural gas producer considering the storage and later withdrawal of gas to take some advantage of an anticipated seasonal and/or secular price increase, with the objective of locking in future prices for current production. Gas would be stored in a low season and later withdrawn and sold, with the price covered by a futures contract or by a dynamic hedging strategy. The expected returns from a natural gas storage/withdrawal scheme are analyzed and the implications of market volatility, price of risk, the local cost of storage, and observations regarding the convenience yield (a difference between the current spot market price and futures market price for future periods) are presented. Analysis of gas storage proposals of specific duration is included as well as evaluation of potential put options created when the storage duration is not fixed. 6 refs., 4 figs., 4 tabs

  16. Predictable topography simulation of SiO2 etching by C5F8 gas combined with a plasma simulation, sheath model and chemical reaction model

    International Nuclear Information System (INIS)

    Takagi, S; Onoue, S; Iyanagi, K; Nishitani, K; Shinmura, T; Kanoh, M; Itoh, H; Shioyama, Y; Akiyama, T; Kishigami, D

    2003-01-01

    We have developed a simulation for predicting reactive ion etching (RIE) topography, which is a combination of plasma simulation, the gas reaction model, the sheath model and the surface reaction model. The simulation is applied to the SiO 2 etching process of a high-aspect-ratio contact hole using C 5 F 8 gas. A capacitively coupled plasma (CCP) reactor of an 8-in. wafer was used in the etching experiments. The baseline conditions are RF power of 1500 W and gas pressure of 4.0 Pa in a gas mixture of Ar, O 2 and C 5 F 8 . The plasma simulation reproduces the tendency that CF 2 radical density increases rapidly and the electron density decreases gradually with increasing gas flow rate of C 5 F 8 . In the RIE topography simulation, the etching profiles such as bowing and taper shape at the bottom are reproduced in deep holes with aspect ratios greater than 19. Moreover, the etching profile, the dependence of the etch depth on the etching time, and the bottom diameter can be predicted by this simulation

  17. The structure and elemental composition of the SiO2 layers with zinc-based nano clusters created by high-dose implantation and annealing

    International Nuclear Information System (INIS)

    Mokhovikov, M.A.; Komarov, F.F.; Vlasukova, L.A.; Mil'chanin, O.V.; Wendler, E.; Wesch, W.; Zhukovski, P.; Vengerek, P.

    2015-01-01

    We present the results of the structure and elemental composition of the SiO 2 layers after high-dose zinc implantation (10 16 - 10 17 sm -2 ) at room temperature and at 500°C, as well as after 700°C annealing. In the case of 'hot' implantation the formation of nano sized (to 5 nm) clusters containing atoms of zinc is registered in as-implanted samples. TEM-analysis proves crystalline structure of these precipitates. Subsequent annealing results in a redistribution of zinc within the implanted layer and in the formation of large crystallites (10 -12 nm for a dose of 5*10 16 cm -2 and 12-18 nm for a dose of 10 17 cm -2 ) in the area of high impurity concentration. (authors)

  18. Highly conformal SiO2/Al2O3 nanolaminate gas-diffusion barriers for large-area flexible electronics applications

    International Nuclear Information System (INIS)

    Choi, Jin-Hwan; Kim, Young-Min; Park, Young-Wook; Park, Tae-Hyun; Jeong, Jin-Wook; Choi, Hyun-Ju; Song, Eun-Ho; Ju, Byeong-Kwon; Lee, Jin-Woo; Kim, Cheol-Ho

    2010-01-01

    The present study demonstrates a flexible gas-diffusion barrier film, containing an SiO 2 /Al 2 O 3 nanolaminate on a plastic substrate. Highly uniform and conformal coatings can be made by alternating the exposure of a flexible polyethersulfone surface to vapors of SiO 2 and Al 2 O 3 , at nanoscale thickness cycles via RF-magnetron sputtering deposition. The calcium degradation test indicates that 24 cycles of a 10/10 nm inorganic bilayer, top-coated by UV-cured resin, greatly enhance the barrier performance, with a permeation rate of 3.79 x 10 -5 g m -2 day -1 based on the change in the ohmic behavior of the calcium sensor at 20 deg. C and 50% relative humidity. Also, the permeation rate for 30 cycles of an 8/8 nm inorganic bilayer coated with UV resin was beyond the limited measurable range of the Ca test at 60 deg. C and 95% relative humidity. It has been found that such laminate films can effectively suppress the void defects of a single inorganic layer, and are significantly less sensitive against moisture permeation. This nanostructure, fabricated by an RF-sputtering process at room temperature, is verified as being useful for highly water-sensitive organic electronics fabricated on plastic substrates.

  19. Effect of input power and gas pressure on the roughening and selective etching of SiO2/Si surfaces in reactive plasmas

    International Nuclear Information System (INIS)

    Zhong, X. X.; Huang, X. Z.; Tam, E.; Ostrikov, K.; Colpo, P.; Rossi, F.

    2010-01-01

    We report on the application low-temperature plasmas for roughening Si surfaces which is becoming increasingly important for a number of applications ranging from Si quantum dots to cell and protein attachment for devices such as 'laboratory on a chip' and sensors. It is a requirement that Si surface roughening is scalable and is a single-step process. It is shown that the removal of naturally forming SiO 2 can be used to assist in the roughening of the surface using a low-temperature plasma-based etching approach, similar to the commonly used in semiconductor micromanufacturing. It is demonstrated that the selectivity of SiO 2 /Si etching can be easily controlled by tuning the plasma power, working gas pressure, and other discharge parameters. The achieved selectivity ranges from 0.4 to 25.2 thus providing an effective means for the control of surface roughness of Si during the oxide layer removal, which is required for many advance applications in bio- and nanotechnology.

  20. Coupling between Ge-nanocrystals and defects in SiO2

    International Nuclear Information System (INIS)

    Skov Jensen, J.; Franzo, G.; Leervad Petersen, T.P.; Pereira, R.; Chevallier, J.; Christian Petersen, M.; Bech Nielsen, B.; Nylandsted Larsen, A.

    2006-01-01

    Room temperature photoluminescence (PL) at around 600 nm from magnetron-sputtered SiO 2 films co-doped with Ge is reported. The PL signal is observed in pure SiO 2 , however, its intensity increases significantly in the presence of Ge-nanocrystals (Ge-nc). The PL intensity has been optimized by varying the temperature of heat treatment, type of gas during heat treatment, concentration of Ge in the SiO 2 films, and gas pressure during deposition. Maximum intensity occurs when Ge-nc of around 3.5 nm are present in large concentration in SiO 2 layers deposited at fairly high gas pressure. Based on time resolved PL, and PL measurements after α-particle irradiation or H passivation, we attribute the origin of the PL to a defect in SiO 2 (probably an O deficiency) that is excited through an energy transfer from Ge-nc. There is no direct PL from the Ge-nc; however, there is a strong coupling between excitons created in the Ge-nc and the SiO 2 defect

  1. 3D for iPhone Apps with Blender and SIO2 Your Guide to Creating 3D Games and More with Open-Source Software

    CERN Document Server

    Mullen, Tony

    2010-01-01

    Create exciting, interactive 3D apps for the iPhone and iPod Touch. What a combination-using free, open-source Blender software and the SI02 game engine to create very cool 3D characters and games for the very hot devices of the moment, the iPhone and iPod Touch. Whether you're coming to this as an iPhone developer or as a Blender artist, this book is for you. Learn how to create 3D content using Blender's WYSIWYG approach, find helpful information on Xcode and other iPhone SDK topics, master physical collisions, and acquire the skills you need to bridge both worlds with fun, compelling conten

  2. On creating of a new pricing policy for natural gas in Bulgaria

    International Nuclear Information System (INIS)

    G'oshev, P.

    1994-01-01

    The joint venture company BULSOFGAS, representing the interests of SOFREGAS (France) and GAZSTROJMONTAZH (Bulgaria) have investigated in 1991 the natural gas usage in household sector in the towns of Montana and Blagoevgrad. The results received show the necessity of introducing a new pricing policy directed to different consumers' groups. The solving of this problem will contribute to: 1) creating possibilities for financing the projects, their realisation and motivation of users; 2) generating preconditions for setting up domestic corporations involved in organizing, financing and operation of urban gas supply networks; 3) more efficient and economically beneficial usage of energy sources at a significantly higher comfort. A special attention is paid to the government activities in this matter. (orig.)

  3. Greenhouse gas emissions from a created brackish marsh in eastern North Carolina

    Science.gov (United States)

    Shiau, Yo-Jin; Burchell, Michael R.; Krauss, Ken W.; Birgand, François; Broome, Stephen W.

    2016-01-01

    Tidal marsh creation helps remediate global warming because tidal wetlands are especially proficient at sequestering carbon (C) in soils. However, greenhouse gas (GHG) losses can offset the climatic benefits gained from C storage depending on how these tidal marshes are constructed and managed. This study attempts to determine the GHG emissions from a 4–6 year old created brackish marsh, what environmental factors governed these emissions, and how the magnitude of the fluxes relates to other wetland ecosystems. The static flux chamber method was used to measure GHG fluxes across three distinct plant zones segregated by elevation. The major of soil GHG fluxes from the marsh were from CO2 (−48–192 mg C m-2 h-1), although it was near the lower end of values reported from other wetland types having lower salinities, and would mostly be offset by photosynthetic uptake in this created brackish marsh. Methane flux was also low (−0.33–0.86 mg C m-2 h-1), likely inhibited by the high soil SO42−and soil redox potentials poised above −150 mV in this in this created brackish marsh environment. Low N2O flux (−0.11–0.10 mg N m-2 h-1) was due to low soil NO3− and soil redox conditions favoring complete denitrification. GHG fluxes from this created brackish marsh were generally lower than those recorded from natural marshes, suggesting that C sequestration may not be offset by the radiative forcing from soil GHG emissions if projects are designed properly.

  4. LNG (Liquefied Natural Gas): the natural gas becoming a world commodity and creating international price references; GNL (Gas Natural Liquefeito): o gas natural se tornando uma commodity mundial e criando referencias de preco internacionais

    Energy Technology Data Exchange (ETDEWEB)

    Demori, Marcio Bastos [PETROBRAS, Rio de Janeiro, RJ (Brazil). Coordenacao de Comercializacao de Gas e GNL; Santos, Edmilson Moutinho dos [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Programa Interunidades de Pos-Graduacao em Energia (PIPGE)

    2004-07-01

    The transportation of large quantities of natural gas through long distances has been done more frequently by Liquefied Natural Gas (LNG). The increase of natural gas demand and the distance of major reserves, allied to technological improvements and cost reduction through LNG supply chain, have triggered the expressive increase of LNG world market This paper tries to evaluate the influence that LNG should cause on natural gas world market dynamic, analyzing the tendency of gas to become a world commodity, creating international price references, like oil and its derivates. For this, are shown data as natural gas world reserves, the participation of LNG in natural gas world market and their increase. Furthermore, will be analyzed the interaction between major natural gas reserves and their access to major markets, still considering scheduled LNG projects, the following impacts from their implementation and price arbitrage that should be provoked on natural gas markets. (author)

  5. Reduction Mechanisms of Cu2+-Doped Na2O-Al2O3-SiO2 Glasses during Heating in H2 Gas.

    Science.gov (United States)

    Nogami, Masayuki; Quang, Vu Xuan; Ohki, Shinobu; Deguchi, Kenzo; Shimizu, Tadashi

    2018-01-25

    Controlling valence state of metal ions that are doped in materials has been widely applied for turning optical properties. Even though hydrogen has been proven effective to reduce metal ions because of its strong reducing capability, few comprehensive studies focus on practical applications because of the low diffusion rate of hydrogen in solids and the limited reaction near sample surfaces. Here, we investigated the reactions of hydrogen with Cu 2+ -doped Na 2 O-Al 2 O 3 -SiO 2 glass and found that a completely different reduction from results reported so far occurs, which is dominated by the Al/Na concentration ratio. For Al/Na glass body. For Al/Na > 1, on the other hand, the reduction of Cu 2+ ions occurred simultaneously with the formation of OH bonds, whereas the reduced Cu metal moved outward and formed a metallic film on glass surface. The NMR and Fourier transform infrared results indicated that the Cu 2+ ions were surrounded by Al 3+ ions that formed AlO 4 , distorted AlO 4 , and AlO 5 units. The diffused H 2 gas reacted with the Al-O - ···Cu + units, forming Al-OH and metallic Cu, the latter of which moved freely toward glass surface and in return enhanced H 2 diffusion.

  6. Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

    SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

  7. Role of chamber dimension in fluorocarbon based deposition and etching of SiO2 and its effects on gas and surface-phase chemistry

    International Nuclear Information System (INIS)

    Joseph, E. A.; Zhou, B.-S.; Sant, S. P.; Overzet, L. J.; Goeckner, M. J.

    2008-01-01

    It is well understood that chamber geometry is an influential factor governing plasma processing of materials. Simple models suggest that a large fraction of this influence is due to changes in basic plasma properties, namely, density, temperature, and potential. However, while such factors do play an important role, they only partly describe the observed differences in process results. Therefore, to better elucidate the role of chamber geometry in this work, the authors explore the influence of plasma chemistry and its symbiotic effect on plasma processing by decoupling the plasma density, temperature, and potential from the plasma-surface (wall) interactions. Specifically, a plasma system is used with which the authors can vary the chamber dimension so as to vary the plasma-surface interaction directly. By varying chamber wall diameter, 20-66 cm, and source-platen distance, 4-6 cm, the etch behavior of SiO 2 (or the deposition behavior of fluorocarbon polymer) and the resulting gas-phase chemistry change significantly. Results from in situ spectroscopic ellipsometry show significant differences in etch characteristics, with etch rates as high as 350 nm/min and as low as 75 nm/min for the same self-bias voltage. Fluorocarbon deposition rates are also highly dependent on chamber dimension and vary from no net deposition to deposition rates as high as 225 nm/min. Etch yields, however, remain unaffected by the chamber size variations. From Langmuir probe measurements, it is clear that chamber geometry results in significant shifts in plasma properties such as electron and ion densities. Indeed, such measurements show that on-wafer processes are limited at least in part by ion flux for high energy reactive ion etch. However, in situ multipass Fourier transform infrared spectroscopy reveals that the line-averaged COF 2 , SiF 4 , CF 2 , and CF 3 gas-phase densities are also dependent on chamber dimension at high self-bias voltage and also correlate well to the CF x

  8. Effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex multi-doped composite coating produced through electrodeposition on oil and gas storage tap

    Directory of Open Access Journals (Sweden)

    P.A.L. Anawe

    2018-06-01

    Full Text Available The effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex zinc multi-doped composite coating produced through electrodeposition is studied. The degradation behaviour in term of wear and chemical corrosion activities were considered as a major factor in service. The wear mass loss was carried out with the help of reciprocating tester. The electrochemical corrosion characteristics were investigated using linear polarization technique in 3.5% simulated sodium chloride media. The outcome of the analysis shows that the developed coating was seen to provide a sound anti wear characteristics in its multidoped state. The corrosion resistance properties were observed to be massive compared to the binary based sample. It is expected that this characteristic will impact on the performance life span of storage tap in oil and gas. Keywords: Zn-SnO2-SiO2, Nanocomposite, Electrodeposition, Coatings and corrosion resistance

  9. Problems of creating fuel elements for fast gas-cooled reactors working on N2O4-dissociating coolant

    International Nuclear Information System (INIS)

    Nesterenko, V.B.; Zelensky, V.F.; Kolykhan, L.I.; Karpenko, G.V.; Krasnorutsky, V.S.; Isakov, V.P.; Ashikhmin, V.P.; Permyakov, L.N.

    1985-01-01

    A variant of fast gas-cooled reactors is one using dissociating N 2 O 4 nitrogen tetroxide as a coolant. This type of reactors is promising because of great thermal effects of dissociation reactions while heating and recombination while cooling; small latent heat of evaporation; high heat transfer coefficient owing to additional heat transfer in a chemical reaction; high N 2 O 4 density in a gas state at operation parameters. The mentioned advantages give possibility to create a small turbine, heat exchange apparatus and to get high heat production in the active zone. All this opens new ways to increase power plants effectiveness

  10. Feasibility of gas-discharge and optical methods of creating artificial ozone layers of the earth

    International Nuclear Information System (INIS)

    Batanov, G.M.; Kossyi, I.A.; Matveev, A.A.; Silakov, V.P.

    1996-01-01

    Gas-discharge (microwave) and optical (laser) methods of generating large-scale artificial ozone layers in the stratosphere are analyzed. A kinetic model is developed to calculate the plasma-chemical consequences of discharges localized in the stratosphere. Computations and simple estimates indicate that, in order to implement gas-discharge and optical methods, the operating power of ozone-producing sources should be comparable to or even much higher than the present-day power production throughout the world. Consequently, from the engineering and economic standpoints, microwave and laser methods cannot be used to repair large-scale ozone 'holes'

  11. A novel gridding algorithm to create regional trace gas maps from satellite observations

    Science.gov (United States)

    Kuhlmann, G.; Hartl, A.; Cheung, H. M.; Lam, Y. F.; Wenig, M. O.

    2014-02-01

    The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2) onto a longitude-latitude grid (level 3). The algorithm is designed for the Ozone Monitoring Instrument (OMI) and can easily be employed for similar instruments - for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI). Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly developed gridding

  12. A novel gridding algorithm to create regional trace gas maps from satellite observations

    Directory of Open Access Journals (Sweden)

    G. Kuhlmann

    2014-02-01

    Full Text Available The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2 onto a longitude–latitude grid (level 3. The algorithm is designed for the Ozone Monitoring Instrument (OMI and can easily be employed for similar instruments – for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI. Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly

  13. Longitudinal Plasmoid in High-Speed Vortex Gas Flow Created by Capacity HF Discharge

    Science.gov (United States)

    2010-10-28

    interferometer with high space resolution, PIV method, FTIR spectrometer, optical spectrometer, pressure sensors with high time resolution, IR pyrometer and...of strong LP-vortex interaction. Intensive acoustic waves are created by CHFD in swirl flow in this regime. 38. Study of control of a longitudinal...quartz tube, 4- HF ball electrode, 5- Tesla’s transformer, 6- microwave interferometer, 7- video camera, 8-optical pyrometer , 9-pressure sensor, 10

  14. Hydraulic fracturing in shales: the spark that created an oil and gas boom

    Science.gov (United States)

    Olson, J. E.

    2017-12-01

    In the oil and gas business, one of the valued properties of a shale was its lack of flow capacity (its sealing integrity) and its propensity to provide mechanical barriers to hydraulic fracture height growth when exploiting oil and gas bearing sandstones. The other important property was the high organic content that made shale a potential source rock for oil and gas, commodities which migrated elsewhere to be produced. Technological advancements in horizontal drilling and hydraulic fracturing have turned this perspective on its head, making shale (or other ultra-low permeability rocks that are described with this catch-all term) the most prized reservoir rock in US onshore operations. Field and laboratory results have changed our view of how hydraulic fracturing works, suggesting heterogeneities like bedding planes and natural fractures can cause significant complexity in hydraulic fracture growth, resulting in induced networks of fractures whose details are controlled by factors including in situ stress contrasts, ductility contrasts in the stratigraphy, the orientation and strength of pre-existing natural fractures, injection fluid viscosity, perforation cluster spacing and effective mechanical layer thickness. The stress shadowing and stress relief concepts that structural geologists have long used to explain joint spacing and orthogonal fracture pattern development in stratified sequences are key to understanding optimal injection point spacing and promotion of more uniform length development in induced hydraulic fractures. Also, fracture interaction criterion to interpret abutting vs crossing natural fracture relationships in natural fracture systems are key to modeling hydraulic fracture propagation within natural fractured reservoirs such as shale. Scaled physical experiments provide constraints on models where the physics is uncertain. Numerous interesting technical questions remain to be answered, and the field is particularly appealing in that better

  15. Effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex multi-doped composite coating produced through electrodeposition on oil and gas storage tap

    Science.gov (United States)

    Anawe, P. A. L.; Fayomi, O. S. I.; Ayoola, A. A.; Popoola, A. P. I.

    2018-06-01

    The effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex zinc multi-doped composite coating produced through electrodeposition is studied. The degradation behaviour in term of wear and chemical corrosion activities were considered as a major factor in service. The wear mass loss was carried out with the help of reciprocating tester. The electrochemical corrosion characteristics were investigated using linear polarization technique in 3.5% simulated sodium chloride media. The outcome of the analysis shows that the developed coating was seen to provide a sound anti wear characteristics in its multidoped state. The corrosion resistance properties were observed to be massive compared to the binary based sample. It is expected that this characteristic will impact on the performance life span of storage tap in oil and gas.

  16. The use of contained nuclear explosions to create underground reservoirs, and experience of operating these for gas condensate storage

    International Nuclear Information System (INIS)

    Kedrovskij, O.L.; Myasnikov, K.V.; Leonov, E.A.; Romadin, N.M.; Dorodnov, V.F.; Nikiforov, G.A.

    1975-01-01

    Investigations on the creation of underground reservoirs by means of nuclear explosions have been going on in the Soviet Union for many years. In this paper the authors consider three main kinds of sites or formations that can be used for constructing reservoirs by this method, namely, low-permeable rocks, worked-out mines and rock salt formations. Formulae are given for predicting the mechanical effect of an explosion in rocks, taking their strength characteristics into account. Engineering procedures are described for sealing and restoring the emplacement holes, so that they can be used for operating the underground reservoir. Experience with the contruction and operation of a 50 000 m 3 gas-condensate reservoir in a rock salt formation is described. In the appendix to the paper a method is presented for calculating the stability of spherical cavities created by nuclear explosions in rock salt, allowing for the development of elasto-plastic deformations and creep

  17. Loop system for creating jet fuel vapor standards used in the calibration of infrared spectrophotometers and gas chromatographs.

    Science.gov (United States)

    Reboulet, James; Cunningham, Robert; Gunasekar, Palur G; Chapman, Gail D; Stevens, Sean C

    2009-02-01

    A whole body inhalation study of mixed jet fuel vapor and its aerosol necessitated the development of a method for preparing vapor only standards from the neat fuel. Jet fuel is a complex mixture of components which partitions between aerosol and vapor when aspirated based on relative volatility of the individual compounds. A method was desired which could separate the vapor portion from the aerosol component to prepare standards for the calibration of infrared spectrophotometers and a head space gas chromatography system. A re-circulating loop system was developed which provided vapor only standards whose composition matched those seen in an exposure system. Comparisons of nominal concentrations in the exposure system to those determined by infrared spectrophotometry were in 92-95% agreement. Comparison of jet fuel vapor concentrations determined by infrared spectrophotometry compared to head space gas chromatography yielded a 93% overall agreement in trial runs. These levels of agreement show the loop system to be a viable method for creating jet fuel vapor standards for calibrating instruments.

  18. PIV Measurement of Transient 3-D (Liquid and Gas Phases) Flow Structures Created by a Spreading Flame over 1-Propanol

    Science.gov (United States)

    Hassan, M. I.; Kuwana, K.; Saito, K.

    2001-01-01

    In the past, we measured three-D flow structure in the liquid and gas phases that were created by a spreading flame over liquid fuels. In that effort, we employed several different techniques including our original laser sheet particle tracking (LSPT) technique, which is capable of measuring transient 2-D flow structures. Recently we obtained a state-of-the-art integrated particle image velocimetry (IPIV), whose function is similar to LSPT, but it has an integrated data recording and processing system. To evaluate the accuracy of our IPIV system, we conducted a series of flame spread tests using the same experimental apparatus that we used in our previous flame spread studies and obtained a series of 2-D flow profiles corresponding to our previous LSPT measurements. We confirmed that both LSPT and IPIV techniques produced similar data, but IPIV data contains more detailed flow structures than LSPT data. Here we present some of newly obtained IPIV flow structure data, and discuss the role of gravity in the flame-induced flow structures. Note that the application of IPIV to our flame spread problems is not straightforward, and it required several preliminary tests for its accuracy including this IPIV comparison to LSPT.

  19. Creating a Methodology for Coordinating High-resolution Air Quality Improvement Map and Greenhouse Gas Mitigation Strategies in Pittsburgh City

    Science.gov (United States)

    Shi, J.; Donahue, N. M.; Klima, K.; Blackhurst, M.

    2016-12-01

    In order to tradeoff global impacts of greenhouse gases with highly local impacts of conventional air pollution, researchers require a method to compare global and regional impacts. Unfortunately, we are not aware of a method that allows these to be compared, "apples-to-apples". In this research we propose a three-step model to compare possible city-wide actions to reduce greenhouse gases and conventional air pollutants. We focus on Pittsburgh, PA, a city with consistently poor air quality that is interested in reducing both greenhouse gases and conventional air pollutants. First, we use the 2013 Pittsburgh Greenhouse Gas Inventory to update the Blackhurst et al. model and conduct a greenhouse gas abatement potentials and implementation costs of proposed greenhouse gas reduction efforts. Second, we use field tests for PM2.5, NOx, SOx, organic carbon (OC) and elemental carbon (EC) data to inform a Land-use Regression Model for local air pollution at a 100m x 100m spatial level, which combined with a social cost of air pollution model (EASIUR) allows us to calculate economic social damages. Third, we combine these two models into a three-dimensional greenhouse gas cost abatement curve to understand the implementation costs and social benefits in terms of air quality improvement and greenhouse gas abatement for each potential intervention. We anticipated such results could provide policy-maker insights in green city development.

  20. Creating standards: Creating illusions?

    DEFF Research Database (Denmark)

    Linneberg, Mai Skjøtt

    written standards may open up for the creation of illusions. These are created when written standards' content is not in accordance with the perception standard adopters and standard users have of the specific practice phenomenon's content. This general theoretical argument is exemplified by the specific...

  1. VARIABILITY OF THE SiO THERMAL LINE EMISSION TOWARD THE YOUNG L1448-mm OUTFLOW

    International Nuclear Information System (INIS)

    Jimenez-Serra, I.; MartIn-Pintado, J.; RodrIguez-Franco, A.; Winters, J.-M.; Caselli, P.

    2011-01-01

    The detection of narrow SiO thermal emission toward young outflows has been proposed to be a signature of the magnetic precursor of C-shocks. Recent modeling of the SiO emission across C-shocks predicts variations in the SiO line intensity and line shape at the precursor and intermediate-velocity regimes in only a few years. We present high angular resolution (3.''8 x 3.''3) images of the thermal SiO J = 2→1 emission toward the L1448-mm outflow in two epochs (2004 November-2005 February, 2009 March-April). Several SiO condensations have appeared at intermediate velocities (20-50 km s -1 ) toward the redshifted lobe of the outflow since 2005. Toward one of the condensations (clump D), systematic differences of the dirty beams between 2005 and 2009 could be responsible for the SiO variability. At higher velocities (50-80 km s -1 ), SiO could also have experienced changes in its intensity. We propose that the SiO variability toward L1448-mm is due to a real SiO enhancement by young C-shocks at the internal working surface between the jet and the ambient gas. For the precursor regime (5.2-9.2 km s -1 ), several narrow and faint SiO components are detected. The narrow SiO components tend to be compact, transient and show elongated (bow-shock) morphologies perpendicular to the jet. We speculate that these features are associated with the precursor of C-shocks appearing at the interface of the new SiO components seen at intermediate velocities.

  2. Formation of radiative centers in SiO2 by tin high-dose implantation

    International Nuclear Information System (INIS)

    Komarov, F.F.; Parkhomenko, I.N.; Vlasukova, L.A.; Mil'chanin, O.V.; Mokhovikov, M.A.; Wendler, E.; Wesch, W.

    2013-01-01

    The structural transformations in SiO 2 layers implanted with high fluence of Sn ions have been investigated. It has been found that post-implantation annealing results in the β-Sn precipitation as well as the formation of SnO 2 -enriched regions in SiO 2 :Sn matrix. The intensive emission in the range of photon energies 1.5 – 3.5 eV is registered for the implanted and annealed samples. We attribute it to the oxygen deficiency centers created in the SiO 2 :Sn matrix and at the 'nanocluster/SiO 2 ' interfaces. (authors)

  3. Effect of SiO2 Overlayer on WO3 Sensitivity to Ammonia

    Directory of Open Access Journals (Sweden)

    Vibha Srivastava

    2010-06-01

    Full Text Available Ammonia gas sensing properties of tungsten trioxide thick film sensor was investigated. The doping of noble catalysts such as Pt, Pd, Au enhanced the gas sensitivity. Platinum doping was found to result in highest sensitivity. Remarkable sensitivity enhancement was realized by coating WO3 thick film sensors with SiO2 overlayer. Sol gel process derived silica overlayer increased ammonia gas sensitivity for doped as well as undoped sensor.

  4. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  5. SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

    International Nuclear Information System (INIS)

    Boies, Adam M; Girshick, Steven L; Roberts, Jeffrey T; Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane

    2009-01-01

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO 2 ) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO 2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO 2 coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 0 C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10 7 particles cm -3 .

  6. Characterization of Particles Created By Laser-Driven Hydrothermal Processing

    Science.gov (United States)

    2016-06-01

    study for two reasons: (i) Both materials are compositionally high in SiO2 and (ii) form similarly to glass formed by a nuclear explosion, which...creates massive pressures and temperatures. As an example, trinitite is a glass formed by a post-nuclear event with SiO2 making up 50%-75% of its...processing, characterization, obsidian, tektite, natural glass 15. NUMBER OF PAGES 89 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT

  7. Room temperature synthesis of porous SiO2 thin films by plasma enhanced chemical vapor deposition

    OpenAIRE

    Barranco Quero, Ángel; Cotrino Bautista, José; Yubero Valencia, Francisco; Espinós, J. P.; Rodríguez González-Elipe, Agustín

    2004-01-01

    Synthesis of porous SiO2 thin films in room temperature was carried out using plasma enhanced chemical vapor deposition (CVD) in an electron cyclotron resonance microwave reactor with a downstream configuration.The gas adsorption properties and the type of porosity of the SiO2 thin films were assessed by adsorption isotherms of toluene at room temperature.The method could also permit the tailoring synthesis of thin films when both composition and porosity can be simultaneously and independent...

  8. LHC Create

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    LHC Create is an upcoming 2-day workshop held at IdeaSquare in November. Participants from CERN and IPAC school of design will compete to design an exhibit that explains why CERN does what it does. The winner will have their exhibit fully realised and made available to experiments, institutes, and tourism agencies around the world.

  9. Creating Poetry.

    Science.gov (United States)

    Drury, John

    Encouraging exploration and practice, this book offers hundreds of exercises and numerous tips covering every step involved in creating poetry. Each chapter is a self-contained unit offering an overview of material in the chapter, a definition of terms, and poetry examples from well-known authors designed to supplement the numerous exercises.…

  10. A geometrical model of VY Canis Majoris for SiO maser lines

    International Nuclear Information System (INIS)

    Zhou Zhen-Pu; Kaifu, N.

    1984-01-01

    A new geometrical model of VY CMa is proposed to explain the three-peaked spectra of transition upsilon=1,2 J=1-0 of SiO maser emission. In this model the circumstellar envelope of VY CMa is a rotating disk of gas and dust seen nearly edge-on. The disk consists of two regions: a decelerated steady stream near the photosphere of the star and an accelerated one further away. Other geometries are discussed and eliminated. Calculated profiles of SiO maser lines fit well the observations. It is possible to explain the three-peaked profiles of SiO maser lines emitted by NML Cyg, RR Aql, NML Tau, etc. (orig.)

  11. PTAC 2002 annual report : creating value through innovation : facilitating innovation, technology transfer, and collaborative research and development in the upstream oil and gas industry

    International Nuclear Information System (INIS)

    2003-01-01

    Petroleum Technology Alliance Canada (PTAC) is Canada's leading organization that helps in the development and transfer of petroleum technology. This annual report listed the key accomplishments of PTAC in 2002. These include a record participation in PTAC workshops and conferences, the co-hosting of the world's largest unconventional gas and coalbed methane conference with the Canadian Society for Unconventional Gas, and the co-hosting of a conference on climate change and greenhouse gas technology with Climate Change Central. In 2002 PTAC launched an Industrial Energy Audit Incentive with Natural Resources Canada. It also proposed an extension to its mandate to help energy efficiency and greenhouse gas technologies for the hydrocarbon energy industry. In addition, PTAC helped launch 32 research and development projects in 2002. PTAC expects that 2003 will see a shift in focus to sustainable, eco-efficiency and greenhouse gas-reducing technologies for the hydrocarbon energy industry. This annual report includes an auditor's report of PTAC's financial statements. The report includes summarized balance sheet of assets, liabilities/surplus and net assets. It also includes summarized statements of revenues, expenses and surplus for the year ended December 31, 2002 with comparative figures for 2001. 1 tab., 2 figs

  12. Comparisons between TiO2- and SiO2-flux assisted TIG welding processes.

    Science.gov (United States)

    Tseng, Kuang-Hung; Chen, Kuan-Lung

    2012-08-01

    This study investigates the effects of flux compounds on the weld shape, ferrite content, and hardness profile in the tungsten inert gas (TIG) welding of 6 mm-thick austenitic 316 L stainless steel plates, using TiO2 and SiO2 powders as the activated fluxes. The metallurgical characterizations of weld metal produced with the oxide powders were evaluated using ferritoscope, optical microscopy, and Vickers microhardness test. Under the same welding parameters, the penetration capability of TIG welding with TiO2 and SiO2 fluxes was approximately 240% and 292%, respectively. A plasma column made with SiO2 flux exhibited greater constriction than that made with TiO2 flux. In addition, an anode root made with SiO2 flux exhibited more condensation than that made with TiO2 flux. Results indicate that energy density of SiO2-flux assisted TIG welding is higher than that of TiO2-flux assisted TIG welding.

  13. Dependence of Photocatalytic Activity of TiO2-SiO2 Nanopowders

    Directory of Open Access Journals (Sweden)

    M. Riazian

    2014-10-01

    Full Text Available Structural properties and chemical composition change the photocatalytic activity in TiO2-SiO2 nanopowder composite. The SiO2-TiO2 nanostructure is synthesized based on sol–gel method. The nanoparticles are characterized by x-ray fluorescents (XRF, x- ray diffraction (XRD, tunneling electron microscopy (TEM, field emission scanning electron microscopy (FE-SEM, UV-vis. Spectrophotometer and furrier transmission create infrared absorption (FTIR techniques. The rate constant k for the degradation of methylen blue in its aqueous solution under UV irradiation is determined as a measure of photocatalytic activity. Dependence between photocatalytic activity and SiO2 content in the composite is determined. Rate constant k is found dependent on the content of SiO2 in the composite that calcined at 900 oC. The addition of low composition SiO2 to the TiO2 matrix (lower than 45% enhances the photocatalytic activity due to thermal stability and increasing in the surface area. The effects of chemical compositions on the surface topography and the crystallization of phases are studied.

  14. UV-VUV laser induced phenomena in SiO2 glass

    International Nuclear Information System (INIS)

    Kajihara, Koichi; Ikuta, Yoshiaki; Oto, Masanori; Hirano, Masahiro; Skuja, Linards; Hosono, Hideo

    2004-01-01

    Creation and annihilation of point defects were studied for SiO 2 glass exposed to ultraviolet (UV) and vacuum UV (VUV) lights to improve transparency and radiation toughness of SiO 2 glass to UV-VUV laser light. Topologically disordered structure of SiO 2 glass featured by the distribution of Si-O-Si angle is a critical factor degrading transmittance near the fundamental absorption edge. Doping with terminal functional groups enhances the structural relaxation and reduces the number of strained Si-O-Si bonds by breaking up the glass network without creating the color centers. Transmittance and laser toughness of SiO 2 glass for F 2 laser is greatly improved in fluorine-doped SiO 2 glass, often referred as 'modified silica glass'. Interstitial hydrogenous species are mobile and reactive at ambient temperature, and play an important role in photochemical reactions induced by exposure to UV-VUV laser light. They terminate the dangling-bond type color centers, while enhancing the formation of the oxygen vacancies. These findings are utilized to develop a deep-UV optical fiber transmitting ArF laser photons with low radiation damage

  15. Effects of silica composition on gas permeability of ENR/PVC ...

    African Journals Online (AJOL)

    At higher SiO2 loadings, the mechanical strength of the membrane decreased due to the agglomeration of SiO2 particles. Gas permeation test was done on ENR/PVC/SiO2 membranes using NO2 gas and CO2 gas. The permeability of both gasses increased with the amount of SiO2 added to the membrane, which attributed ...

  16. Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

    Science.gov (United States)

    Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

    2018-05-01

    Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

  17. Composite SiOx/hydrocarbon plasma polymer films prepared by RF magnetron sputtering of SiO2 and polyimide

    Czech Academy of Sciences Publication Activity Database

    Drabik, M.; Kousal, J.; Pinosh, Y.; Choukourov, A.; Biederman, H.; Slavínská, D.; Macková, Anna; Boldyryeva, Hanna; Pešička, J.

    2007-01-01

    Roč. 81, č. 7 (2007), s. 920-927 ISSN 0042-207X Institutional research plan: CEZ:AV0Z10480505 Keywords : composite films * magnetron * sputtering * polyimide * SiO2 Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.881, year: 2007

  18. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.; Rajendran, Arvind; Lai, Zhiping

    2013-01-01

    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin

  19. Effect of surface water on tritium release behavior from Li4SiO4

    International Nuclear Information System (INIS)

    Hanada, T.; Fukada, S.; Nishikawa, M.; Suematsu, K.; Yamashita, N.; Kanazawa, T.

    2010-01-01

    The tritium release model to represent the release behavior of bred tritium from solid breeder materials has been developed by the blanket group of Kyushu University. It has been found that water is released to the purge gas from solid breeder materials and that this water affects the tritium release behavior. In this study, the amount of surface water released from Li 4 SiO 4 is quantified by the experiment. In addition, the tritium release behavior from Li 4 SiO 4 are estimated based on the tritium release model using parameters obtained in our studies under conditions of commercial reactor operation and ITER test blanket module operation. The effect of the surface water on tritium release behavior is discussed from the obtained results. Moreover, the tritium inventory of Li 4 SiO 4 is discussed based on calculation under the unsteady state condition. Further, the effects of grain size and temperature on distribution of tritium inventory under the steady state condition are evaluated, and the optimal grain size is discussed from the view point of tritium release from Li 4 SiO 4 .

  20. Report on achievements in fiscal 1998. Venture business growing type consortium - small business creating infrastructure (Research on manufacturing next-generation gas generating agent for air bag); 1998 nendo jisedai air bag yo gas hasseizai no seizo kenkyu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Sodium azide has been used for many years as a gas generating agent for automobiles. However, sodium azide has strong toxicity, and is doubted of carcinogenicity. Bistetrazole having no such a drawback is now noticed as the next-generation gas generating agent, and substitution to gas agents having less toxicity is being advanced worldwide. The present research is intended to develop a method to manufacture bistetrazole (BHT) which does not by-produce wastes in a large amount, is friendly to environment, and economical. Research and development works were performed on manufacturing dicyanide as the raw material by using the electrolytic process and by using the catalytic process, while both processes were found successful. In the reaction to synthesize BHT from the manufactured dicyanide and sodium azide, high crystalline purity and yield as high as 94.5% have been achieved. As a result of having discussed improvement on the one-pot process that synthesizes BHT directly, not going through handling of the produced dicyanide, solution was made on a method to remove impurities, and conditions to produce BHT at high yield were discovered. This new catalytic process provides a total yield of 80%, successfully reducing the manufacturing cost. (NEDO)

  1. Compositional and optical properties of SiO x films and (SiO x /SiO y ) junctions deposited by HFCVD

    Science.gov (United States)

    2014-01-01

    In this work, non-stoichiometric silicon oxide (SiO x ) films and (SiO x /SiO y ) junctions, as-grown and after further annealing, are characterized by different techniques. The SiO x films and (SiO x /SiO y ) junctions are obtained by hot filament chemical vapor deposition technique in the range of temperatures from 900°C to 1,150°C. Transmittance spectra of the SiO x films showed a wavelength shift of the absorption edge thus indicating an increase in the optical energy band gap, when the growth temperature decreases; a similar behavior is observed in the (SiO x /SiO y ) structures, which in turn indicates a decrease in the Si excess, as Fourier transform infrared spectroscopy (FTIR) reveals, so that, the film and junction composition changes with the growth temperature. The analysis of the photoluminescence (PL) results using the quantum confinement model suggests the presence of silicon nanocrystal (Si-nc) embedded in a SiO x matrix. For the case of the as-grown SiO x films, the absorption and emission properties are correlated with quantum effects in Si-nc and defects. For the case of the as-grown (SiO x /SiO y ) junctions, only the emission mechanism related to some kinds of defects was considered, but silicon nanocrystal embedded in a SiO x matrix is present. After thermal annealing, a phase separation into Si and SiO2 occurs, as the FTIR spectra illustrates, which has repercussions in the absorption and emission properties of the films and junctions, as shown by the change in the A and B band positions on the PL spectra. These results lead to good possibilities for proposed novel applications in optoelectronic devices. PACS 61.05.-a; 68.37.Og; 61.05.cp; 78.55.-m; 68.37.Ps; 81.15.Gh PMID:25342935

  2. Design of flexible PANI-coated CuO-TiO2-SiO2 heterostructure nanofibers with high ammonia sensing response values

    Science.gov (United States)

    Pang, Zengyuan; Nie, Qingxin; Lv, Pengfei; Yu, Jian; Huang, Fenglin; Wei, Qufu

    2017-06-01

    We report a room-temperature ammonia sensor with extra high response values and ideal flexibility, including polyaniline (PANI)-coated titanium dioxide-silicon dioxide (TiO2-SiO2) or copper oxide-titanium dioxide-silicon dioxide (CuO-TiO2-SiO2) composite nanofibers. Such flexible inorganic TiO2-SiO2 and CuO-TiO2-SiO2 composite nanofibers were prepared by electrospinning, followed by calcination. Then, in situ polymerization of aniline monomers was carried out with inorganic TiO2-SiO2 and CuO-TiO2-SiO2 composite nanofibers as templates. Gas sensing tests at room temperature indicated that the obtained CuO-TiO2-SiO2/PANI composite nanofibers had much higher response values to ammonia gas (ca. 45.67-100 ppm) than most of those reported before as well as the prepared TiO2-SiO2/PANI composite nanofibers here. These excellent sensing properties may be due to the P-N, P-P heterojunctions and a structure similar to field-effect transistors formed on the interfaces between PANI, TiO2, and CuO, which is p-type, n-type, and p-type semiconductor, respectively. In addition, the prepared free-standing CuO-TiO2-SiO2/PANI composite nanofiber membrane was easy to handle and possessed ideal flexibility, which is promising for potential applications in wearable sensors in the future.

  3. Preparation and Characterization of Fluorescent SiO2 Microspheres

    Science.gov (United States)

    Xu, Cui; Zhang, Hao; Guan, Ruifang

    2018-01-01

    Fluorescent compound without typical fluorophores was synthesized with citric acid (CA) and aminopropyltriethoxysilane (APTS) firstly, and then it was grafted to the surface of the prepared SiO2 microspheres by chemical reaction. The fluorescent SiO2 microspheres with good fluorescent properties were obtained by optimizing the reaction conditions. And the morphology and structure of the fluorescent SiO2 microspheres have been characterized by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. The results showed that the preparation of fluorescent SiO2 microspheres have good monodispersity and narrow particle size distribution. Moreover, the fluorescent SiO2 microspheres can be applied to detect Fe3+ in aqueous solution, prepare fluorescent SiO2 rubber, and have potential to be applied in the fluorescent labeling and fingerprint appearing technique fields.

  4. Efficient photocatalytic activity with carbon-doped SiO2 nanoparticles

    KAUST Repository

    Zhang, Dongen

    2013-01-01

    Photocatalysis provides a \\'green\\' approach to completely eliminate various kinds of contaminants that are fatal for current environmental and energy issues. Semiconductors are one of the most frequently used photocatalysts as they can absorb light over a wide spectral range. However, it is also well known that naked SiO2 is not an efficient photocatalyst due to its relatively large band gap, which could only absorb shortwave ultraviolet light. In this report, nanoscale particles of carbon-doped silicon dioxide (C-doped SiO2) for use in photocatalysis were successfully prepared by a facile one-pot thermal process using tetraethylorthosilicate (TEOS) as the source of both silicon and carbon. These particles were subsequently characterized by thermogravimetric analysis, X-ray diffraction, standard and high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The C-doped SiO2 displayed outstanding photocatalytic properties, as evidenced by its catalysis of Rhodamine B degradation under near-UV irradiation. We propose that carbon doping of the SiO2 lattice creates new energy states between the bottom of the conduction band and the top of the valence band, which narrows the band gap of the material. As a result, the C-doped SiO2 nanoparticles exhibit excellent photocatalytic activities in a neutral environment. The novel synthesis reported herein for this material is both energy efficient and environmentally friendly and as such shows promise as a technique for low-cost, readily scalable industrial production. © 2013 The Royal Society of Chemistry.

  5. Ultrathin Microporous SiO2 Membranes Photodeposited on Hydrogen Evolving Catalysts Enabling Overall Water Splitting

    KAUST Repository

    Bau, Jeremy A.

    2017-10-17

    Semiconductor systems for photocatalytic overall water splitting into H2 and O2 gases typically require metal cocatalyst particles, such as Pt, to efficiently catalyze H2 evolution. However, such metal catalyst surfaces also serve as recombination sites for H2 and O2, forming H2O. We herein report the photon-induced fabrication of microporous SiO2 membranes that can selectively restrict passage of O2 and larger hydrated ions while allowing penetration of protons, water, and H2. The SiO2 layers were selectively photodeposited on Pt nanoparticles on SrTiO3 photocatalyst by using tetramethylammonium (TMA) as a structure-directing agent (SDA), resulting in the formation of core–shell Pt@SiO2 cocatalysts. The resulting photocatalyst exhibited both improved overall water splitting performance under irradiation and with no H2/O2 recombination in the dark. The function of the SiO2 layers was investigated electrochemically by fabricating the SiO2 layers on a Pt electrode via an analogous cathodic deposition protocol. The uniform, dense, yet amorphous layers possess microporosity originating from ring structures formed during the hydrolysis of the silicate precursor in the presence of TMA, suggesting a double-role for TMA in coordinating silicate to cathodic surfaces and in creating a microporous material. The resulting layers were able to function as a molecular sieve, allowing for exclusive H2 generation while excluding unwanted side reactions by O2 or ferricyanide. The SiO2 layer is stable for extended periods of time in photocatalytic conditions, demonstrating promise as a nontoxic material for selective H2 evolution.

  6. Ultrathin Microporous SiO2 Membranes Photodeposited on Hydrogen Evolving Catalysts Enabling Overall Water Splitting

    KAUST Repository

    Bau, Jeremy A.; Takanabe, Kazuhiro

    2017-01-01

    Semiconductor systems for photocatalytic overall water splitting into H2 and O2 gases typically require metal cocatalyst particles, such as Pt, to efficiently catalyze H2 evolution. However, such metal catalyst surfaces also serve as recombination sites for H2 and O2, forming H2O. We herein report the photon-induced fabrication of microporous SiO2 membranes that can selectively restrict passage of O2 and larger hydrated ions while allowing penetration of protons, water, and H2. The SiO2 layers were selectively photodeposited on Pt nanoparticles on SrTiO3 photocatalyst by using tetramethylammonium (TMA) as a structure-directing agent (SDA), resulting in the formation of core–shell Pt@SiO2 cocatalysts. The resulting photocatalyst exhibited both improved overall water splitting performance under irradiation and with no H2/O2 recombination in the dark. The function of the SiO2 layers was investigated electrochemically by fabricating the SiO2 layers on a Pt electrode via an analogous cathodic deposition protocol. The uniform, dense, yet amorphous layers possess microporosity originating from ring structures formed during the hydrolysis of the silicate precursor in the presence of TMA, suggesting a double-role for TMA in coordinating silicate to cathodic surfaces and in creating a microporous material. The resulting layers were able to function as a molecular sieve, allowing for exclusive H2 generation while excluding unwanted side reactions by O2 or ferricyanide. The SiO2 layer is stable for extended periods of time in photocatalytic conditions, demonstrating promise as a nontoxic material for selective H2 evolution.

  7. Suppression of dewetting phenomena during excimer laser melting of thin metal films on SiO2

    International Nuclear Information System (INIS)

    Kline, J.E.; Leonard, J.P.

    2005-01-01

    Pulsed excimer laser irradiation has been used to fully melt 200 nm films of elemental Au and Ni on SiO 2 substrates. With the use of a capping layer of SiO 2 and line irradiation via projection optics, the typical liquid-phase dewetting processes associated with these metals on SiO 2 has been suppressed. In a series of experiments varying line widths and fluence, a process region is revealed immediately above the complete melting threshold for which the films remain continuous and smooth after melting and resolidification. Simple energetic arguments for mechanisms leading to initiation of dewetting support these observations, and a gas-mediated model is proposed to describe the process conditions that are necessary for the suppression of dewetting

  8. Thickness measurement of SiO2 films thinner than 1 nm by X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Joong Kim, Kyung; Park, Ki Tae; Lee, Jong Wan

    2006-01-01

    The thickness measurement of ultra-thin SiO 2 films thinner than 1 nm was studied by X-ray photoelectron spectroscopy (XPS). Amorphous SiO 2 thin films were grown on amorphous Si films to avoid the thickness difference due to the crystalline structure of a substrate. SiO 2 thin films were grown by ion beam sputter deposition under oxygen gas flow and the thickness was measured by in situ XPS. The attenuation length was determined experimentally by a SiO 2 film with a known thickness. The straight line fit between the measured thickness using XPS and the nominal thickness showed a good linear relation with a gradient of 0.969 and a small offset of 0.126 nm. The gradient measured at the range of 3.4-0.28 nm was very close to that measured at sub-nanometer range of 1.13-0.28 nm. This result means that the reliable measurement of SiO 2 film thickness below 1 nm is possible by XPS

  9. Magnesium Removal from an Aluminum A-332 Molten Alloy Using Enriched Zeolite with Nanoparticles of SiO2

    Directory of Open Access Journals (Sweden)

    R. Muñoz-Arroyo

    2014-01-01

    Full Text Available In order to improve the Mg removal from an A-380 molten alloy, mixtures of zeolite and SiO2 nanoparticles (SiO2(NPs were tested. Zeolite was enriched with 2.5, 5, 7.5, 10, or 12.5 wt-% of amorphous SiO2(NPs. The SiO2(NPs and zeolite were mixed for 30 min in ethanol for each experiment and then dried in a furnace at 80°C for 12 h. The enriched zeolites were analyzed by scanning electron microscopy, transmission electron microscopy, and N2 gas adsorption analysis. The Mg removal was carried out injecting each mixture into the molten aluminum alloy at 750°C using argon. The Mg content of the molten alloy was measured after different periods of the injection time. Zeolites enriched with 2.5 and 5 wt-% of SiO2(NPs were demonstrated to be the better mixtures, removing Mg from an initial content of 1.6 to a final content of 0.0002 and 0.0101 wt-%, respectively, in 45 min of injection.

  10. Kinetics of the Coupled Gas-Iron Reactions Involving Silicon and ...

    African Journals Online (AJOL)

    The kinetic study of coupled gas-iron reactions at 15600 has been carried out for the system involving liquid iron containing carbon and silicon and a gas phase consisting carbon monoxide, silicon monoxide and carbon dioxide. The coupled reactions are: (1) 200(g) = CO2 + C. (2) SiO (g) + CO (g) = Si ¸ CO (g). (3) SiO (g) + ...

  11. Osteoblast interaction with laser cladded HA and SiO2-HA coatings on Ti-6Al-4V

    International Nuclear Information System (INIS)

    Yang Yuling; Serpersu, Kaan; He Wei; Paital, Sameer R.; Dahotre, Narendra B.

    2011-01-01

    In order to improve the bioactivity and biocompatibility of titanium endosseous implants, the morphology and composition of the surfaces were modified. Polished Ti-6Al-4V substrates were coated by a laser cladding process with different precursors: 100 wt.% HA and 25 wt.% SiO 2 -HA. X-ray diffraction of the laser processed samples showed the presence of CaTiO 3 , Ca 3 (PO 4 ) 2 , and Ca 2 SiO 4 phases within the coatings. From in vitro studies, it was observed that compared to the unmodified substrate all laser cladded samples presented improved cellular interactions and bioactivity. The samples processed with 25 wt.% SiO 2 -HA precursor showed a significantly higher HA precipitation after immersion in simulated body fluid than 100 wt.% HA precursor and titanium substrates. The in vitro biocompatibility of the laser cladded coatings and titanium substrate was investigated by culturing of mouse MC3T3-E1 pre-osteoblast cell line and analyzing the cell viability, cell proliferation, and cell morphology. A significantly higher cell attachment and proliferation rate were observed for both laser cladded 100 wt.% HA and 25 wt.% SiO 2 -HA samples. Compared to 100 wt.% HA sample, 25 wt.% SiO 2 -HA samples presented a slightly improved cellular interaction due to the addition of SiO 2 . The staining of the actin filaments showed that the laser cladded samples induced a normal cytoskeleton and well-developed focal adhesion contacts. Scanning electron microscopic image of the cell cultured samples revealed better cell attachment and spreading for 25 wt.% SiO 2 -HA and 100 wt.% HA coatings than titanium substrate. These results suggest that the laser cladding process improves the bioactivity and biocompatibility of titanium. The observed biological improvements are mainly due to the coating induced changes in surface chemistry and surface morphology. Highlights: → Laser cladding of Ti alloys with bioceramics creates new phases. → Laser cladded samples with SiO 2 -doped

  12. sio-137, um drama recontado

    OpenAIRE

    Vieira,Suzane de Alencar

    2013-01-01

    O acidente radiológico com césio-137, desencadeado na cidade de Goiânia no ano 1987, não se encerra com o fim da contaminação radiológica e se estende a um processo judicial, médico-científico e narrativo de identificação e reconhecimento de novas vítimas. O drama ocupa um lugar central na dinâmica do evento radiológico ao estender seus limites, modular sua intensidade e atualizá-lo a cada nova narrativa. A etnografia, enquanto uma narrativa sobre o evento, incorpora e atualiza o drama como m...

  13. SiO EMISSION AS A TRACER OF X-RAY DOMINATED CHEMISTRY IN THE GALACTIC CENTER

    International Nuclear Information System (INIS)

    Amo-Baladron, M. A.; Martin-Pintado, J.; Morris, M. R.; Muno, M. P.; RodrIguez-Fernandez, N. J.

    2009-01-01

    We present emission maps of the Sgr A molecular cloud complex at the Galactic center (GC) in the J = 2 → 1 line of SiO observed with the IRAM 30 m telescope at Pico Veleta. Comparing our SiO(2-1) data cube with that of CS(1-0) emission with similar angular and velocity resolution, we find a correlation between the SiO/CS line intensity ratio and the equivalent width of the Fe Kα fluorescence line at 6.4 keV. We discuss the SiO abundance enhancement in terms of the two most plausible scenarios for the origin of the 6.4 keV Fe line: X-ray reflection nebula (XRN) and low-energy cosmic rays (LECRs). Both scenarios could explain the enhancement in the SiO/CS intensity ratio with the intensity of the 6.4 keV Fe line, but both present difficulties. The XRN scenario requires a population of very small grains to produce the SiO abundance enhancement, together with a past episode of bright X-ray emission from some source in the GC, possibly the central supermassive black hole, SgrA*, ∼300 yr ago. The LECR scenario needs higher gas column densities to produce the observed 6.4 keV Fe line intensities than those derived from our observations. It is possible to explain the SiO abundance enhancement if the LECRs originate in supernovae and their associated shocks produce the SiO abundance enhancement. However, the LECR scenario cannot account for the time variability of the 6.4 keV Fe line, which can be naturally explained by the XRN scenario.

  14. Studying of Nano SiO2 Preparation from Rice Husk Ash by Using High Gravity Reaction Precipitation Technology

    International Nuclear Information System (INIS)

    Nguyen Thanh Chung; Tran Ngoc Ha; Hoang Van Duc

    2013-01-01

    A novel method (High-gravity reactive precipitation - HGRP) was developed to prepare nano-SiO 2 from rice husk ash using gas-liquid reaction system. The precipitated silica produced by our proposed method had average size of 20 nm with narrow size distribution and purity of SiO 2 was approximately 99.2%. The principles of the method as well as experimental conditions were also described. (author)

  15. Synthesis and Luminescence Properties of Yellow-emitting SiO2/Zn2SiO4: Mn Nanocomposite

    Directory of Open Access Journals (Sweden)

    Karim OMRI

    2014-05-01

    Full Text Available Yellow light emitting Mn2+-doped b-Zn2SiO4 phosphor nanoparticles embedded in SiO2 host matrix, were prepared by a simple solid-phase reaction under natural atmosphere at 1500 °C for 2 hours after the incorporation of manganese doped zinc oxide nanoparticles in silica using sol-gel method. The SiO2/Zn2SiO4:Mn nanocomposite was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM and photoluminescence (PL. The nanopowder was crystallized in triclinic b-Zn2SiO4 phase with a particles size varies between 70 nm and 84 nm. The SiO2/b-Zn2SiO4:Mn nanocomposite exhibited a broad yellow emission band at 575 nm under UV excitation light. The dependence of the intensity and energy position of the obtained PL band on measurement temperature and power excitation will be discussed.

  16. Effect of interfacial SiO2- y layer and defect in HfO2- x film on flat-band voltage of HfO2- x /SiO2- y stacks for backside-illuminated CMOS image sensors

    Science.gov (United States)

    Na, Heedo; Lee, Jimin; Jeong, Juyoung; Kim, Taeho; Sohn, Hyunchul

    2018-03-01

    In this study, the effect of oxygen gas fraction during deposition of a hafnium oxide (HfO2- x ) film and the influence of the quality of the SiO2- y interlayer on the nature of flat-band voltage ( V fb) in TiN/HfO/SiO2- y /p-Si structures were investigated. X-ray photoemission spectroscopy analysis showed that the non-lattice oxygen peak, indicating an existing oxygen vacancy, increased as the oxygen gas fraction decreased during sputtering. From C- V and J- E analyses, the V fb behavior was significantly affected by the characteristics of the SiO2- y interlayer and the non-lattice oxygen fraction in the HfO2- x films. The HfO2- x /native SiO2- y stack presented a V fb of - 1.01 V for HfO2- x films with an oxygen gas fraction of 5% during sputtering. Additionally, the V fb of the HfO2- x /native SiO2- y stack could be controlled from - 1.01 to - 0.56 V by changing the deposition conditions of the HfO2- x film with the native SiO2- y interlayer. The findings of this study can be useful to fabricate charge-accumulating layers for backside-illuminated image sensor devices.

  17. Matrix solid-phase dispersion extraction of organophosphorus pesticide using SiO2-poly(N-vinylimidazole)

    International Nuclear Information System (INIS)

    Gutiérrez-Solís, M C; Muñoz-Rodríguez, D; Carrera-Figueiras, C; Ávila-Ortega, A; Medina-Peralta, S

    2013-01-01

    A sorbent material based on silica particles modified with poly(N-vinylimidazole) (SiO 2 -PVI) has been evaluated for the treatment of samples by matrix solid-phase dispersion (MSPD). The extraction of four organophosphorus pesticides was done from a spiked tomato and the extracts were analyzed by gas chromatography coupled to mass spectrometry. Six elution solvents were evaluated and acetone was selected due to better recovery of the four pesticides and low background signal in the chromatograms. A factorial design 2 4 was used for selection of extraction conditions. The factors were contact time, acetone volume, treatment (with or without freeze-drying) and adsorbent (SiO 2 or SiO 2 -PVI). The best recoveries were obtained using 15 minutes of contact, 2 mL of solvent and sorbent without freeze-drying. The recoveries were between 60 and 83% for SiO 2 -PVI in spiked tomato with 0.2 and 0.8μg/g.

  18. A comparison of Rh/CeO2/SiO2 catalysts with steam reforming catalysts, dolomite and inert materials as bed materials in low throughput fluidized bed gasification systems

    International Nuclear Information System (INIS)

    Asadullah, Mohammad; Miyazawa, Tomohisa; Ito, Shin-ichi; Kunimori, Kimio; Koyama, Shuntarou; Tomishige, Keiichi

    2004-01-01

    The gasification of cedar wood in the presence of Rh/CeO 2 /SiO 2 has been conducted in the laboratory scale fluidized bed reactor using air as a gasifying agent at low temperatures (823-973 K) in order to produce high-quality fuel gas for gas turbine for power generation. The performance of the Rh/CeO 2 /SiO 2 catalyst has been compared with conventional catalysts such as commercial steam reforming catalyst G-91, dolomite and noncatalyst systems by measurements of the cold gas efficiency, tar concentration, carbon conversion to gas and gas composition. The tar concentration was completely negligible in the Rh/CeO 2 /SiO 2 -catalyzed product gas whereas it was about 30, 113, and 139 g/m 3 in G-91, dolomite and noncatalyzed product gas, respectively. Since the carbon conversion to useful gas such as CO, H 2 , and CH 4 are much higher on Rh/CeO 2 /SiO 2 catalyst than others at 873 K, the cold gas efficiency is much higher (71%) in this case than others. The hydrogen content in the product gas is much higher (>24 vol%) than the specified level (>10 vol%) for efficient combustion in the gas turbine engine. The char and coke formation is also very low on Rh/CeO 2 /SiO 2 catalyst than on the conventional catalysts. Although the catalyst surface area was slightly decreased after using the same catalyst in at least 20 experiments, the deactivation problem was not severe

  19. Creating a super market

    International Nuclear Information System (INIS)

    Katz, M.

    1994-01-01

    FERC (Federal Energy Regulatory Commission) Order 636 changed gas marketing procedures in October 1993 by disengaging the remaining linkages between producers, pipeline companies and LDCs. By erasing the pipelines' already disappearing role as gas suppliers, Order 636 made LDCs entirely responsible for obtaining their own gas supply, transportation and storage. So, many LDCs turned to gas marketing companies -- not only for more gas, but also for many of the services that the pipelines and gas suppliers used to provide. The process is giving the gas marketing companies a whole new role in life -- perhaps even a whole new life. Unlike LDCs and the pipelines, gas marketers are largely unregulated and, as such, are moving into or looking at a host of new areas: Helping customers manage and economize their energy use, not only with natural gas but with other fuels as well; Marketing electricity and fuel oil in addition to natural gas; Laying pipelines and serving local industrial customers the LDCs haven't been able to serve economically; and Selling natural gas to individual residential customers, the last remaining exclusive domain of the LDCs. The paper discusses the new roles for gas marketing companies and what is left for LDCs

  20. Create Your Plate

    Medline Plus

    Full Text Available ... Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective ... foods within each food category. Try these seven steps to get started: Using your dinner plate, put ...

  1. Create Your Plate

    Medline Plus

    Full Text Available ... for Association Events Messaging Tools Recruiting Advocates Local Market Planning Training Webinars News & Events Advocacy News Call ... Meals > Create Your Plate Share: Print Page Text Size: A A A Listen En Español Create Your ...

  2. Create Your Plate

    Medline Plus

    Full Text Available ... of the differences in types of vegetables. When creating your plate at home, remember that half of ... effective for both managing diabetes and losing weight. Creating your plate lets you still choose the foods ...

  3. Estimation of the depth resolution of secondary ion mass spectrometry at the interface SiO2/Si

    Science.gov (United States)

    Kocanda, J.; Fesič, V.; Veselý, M.; Breza, J.; Kadlečíková, M.

    1995-08-01

    Similarities between the processes that occur during sputtering of monocrystalline Si by reactive O2+ primary ions and the interface SiO2/monocrystalline Si by noble gas ions (e.g., by Ar+) have motivated us to utilize the semiempirical model of P. C. Zalm and C. J. Vriezema [Nucl. Instrum. Methods B 67, 495 (1992)], modified later by M. Petravić, B. G. Svensson, and J. S. Williams [Appl. Phys. Lett. 62, 278 (1993)] to calculate the decay length λb, as defined by J. B. Clegg [Surf. Interface Anal. 10, 322 (1987)], at the SiO2/Si interface. The measured and calculated results agree remarkably well. Inconsistency observed to be larger than 100% for glancing incidence angles confirms limitations of this model that were admitted already by its authors.

  4. Synchrotron radiation stimulated etching of SiO sub 2 thin films with a Co contact mask for the area-selective deposition of self-assembled monolayer

    CERN Document Server

    Wang, C

    2003-01-01

    The area-selective deposition of a self-assembled monolayer (SAM) was demonstrated on a pattern structure fabricated by synchrotron radiation (SR) stimulated etching of a SiO sub 2 thin film on the Si substrate. The etching was conducted by irradiating the SiO sub 2 thin film with SR through a Co contact mask and using a mixture of SF sub 6 + O sub 2 as the reaction gas. The SR etching stopped completely at the SiO sub 2 /Si interface. After the SR etching, the Si surface and the SiO sub 2 surface beneath the Co mask were evaluated by an atomic force microscope (AFM). A dodecene SAM was deposited on the Si surface, and trichlorosilane-derived SAMs (octadecyltrichlorosilane, and octenyltrichlorosilane) were deposited on the SiO sub 2 surface beneath the Co mask. The structure of the deposited SAMs showed a densely packed and well-ordered molecular architecture, which was characterized by infrared spectroscopy, ellipsometry, and water contact angle (WCA) measurements. (author)

  5. Comparison of interfaces for (Ba,Sr)TiO3 films deposited on Si and SiO2/Si substrates

    International Nuclear Information System (INIS)

    Suvorova, N.A.; Lopez, C.M.; Irene, E.A.; Suvorova, A.A.; Saunders, M.

    2004-01-01

    (Ba,Sr)TiO 3 (BST) thin films were deposited by ion sputtering on both bare and oxidized Si. Spectroscopic ellipsometry results have shown that a SiO 2 underlayer of nearly the same thickness (2.6 nm in average) is found at the Si interface for BST sputter depositions onto nominally bare Si, 1 nm SiO 2 on Si or 3.5 nm SiO 2 on Si. This result was confirmed by high-resolution electron microscopy analysis of the films, and it is believed to be due to simultaneous subcutaneous oxidation of Si and reaction of the BST layer with SiO 2 . Using the conductance method, capacitance-voltage measurements show a decrease in the interface trap density D it of an order of magnitude for oxidized Si substrates with a thicker SiO 2 underlayer. Further reduction of D it was achieved for the capacitors grown on oxidized Si and annealed in forming gas after metallization

  6. Comparison of interfaces for (Ba,Sr)TiO3 films deposited on Si and SiO2/Si substrates

    Science.gov (United States)

    Suvorova, N. A.; Lopez, C. M.; Irene, E. A.; Suvorova, A. A.; Saunders, M.

    2004-03-01

    (Ba,Sr)TiO3(BST) thin films were deposited by ion sputtering on both bare and oxidized Si. Spectroscopic ellipsometry results have shown that a SiO2 underlayer of nearly the same thickness (2.6 nm in average) is found at the Si interface for BST sputter depositions onto nominally bare Si, 1 nm SiO2 on Si or 3.5 nm SiO2 on Si. This result was confirmed by high-resolution electron microscopy analysis of the films, and it is believed to be due to simultaneous subcutaneous oxidation of Si and reaction of the BST layer with SiO2. Using the conductance method, capacitance-voltage measurements show a decrease in the interface trap density Dit of an order of magnitude for oxidized Si substrates with a thicker SiO2 underlayer. Further reduction of Dit was achieved for the capacitors grown on oxidized Si and annealed in forming gas after metallization.

  7. The ceramic SiO2 and SiO2-TiO2 coatings on biomedical Ti6Al4VELI titanium alloy

    International Nuclear Information System (INIS)

    Surowska, B.; Walczak, M.; Bienias, J.

    2004-01-01

    The paper presents the study of intermediate SiO 2 and SiO 2 -TiO 2 sol-gel coatings and dental porcelain coatings on Ti6Al4VELI titanium alloy. Surface microstructures and wear behaviour by pin-on-disc method of the ceramic coatings were investigated. The analysis revealed: (1) a compact, homogeneous SiO 2 and SiO 2 -TiO 2 coating and (2) that intermediate coatings may provide a durable joint between metal and porcelain, and (3) that dental porcelain on SiO 2 and TiO 2 coatings shows high wear resistance. (author)

  8. Do SiO 2 and carbon-doped SiO 2 nanoparticles melt? Insights from QM/MD simulations and ramifications regarding carbon nanotube growth

    Science.gov (United States)

    Page, Alister J.; Chandrakumar, K. R. S.; Irle, Stephan; Morokuma, Keiji

    2011-05-01

    Quantum chemical molecular dynamics (QM/MD) simulations of pristine and carbon-doped SiO 2 nanoparticles have been performed between 1000 and 3000 K. At temperatures above 1600 K, pristine nanoparticle SiO 2 decomposes rapidly, primarily forming SiO. Similarly, carbon-doped nanoparticle SiO 2 decomposes at temperatures above 2000 K, primarily forming SiO and CO. Analysis of the physical states of these pristine and carbon-doped SiO 2 nanoparticles indicate that they remain in the solid phase throughout decomposition. This process is therefore one of sublimation, as the liquid phase is never entered. Ramifications of these observations with respect to presently debated mechanisms of carbon nanotube growth on SiO 2 nanoparticles will be discussed.

  9. Total Ionizing Dose Effects of Si Vertical Diffused MOSFET with SiO2 and Si3N4/SiO2 Gate Dielectrics

    Directory of Open Access Journals (Sweden)

    Jiongjiong Mo

    2017-01-01

    Full Text Available The total ionizing dose irradiation effects are investigated in Si vertical diffused MOSFETs (VDMOSs with different gate dielectrics including single SiO2 layer and double Si3N4/SiO2 layer. Radiation-induced holes trapping is greater for single SiO2 layer than for double Si3N4/SiO2 layer. Dielectric oxidation temperature dependent TID effects are also studied. Holes trapping induced negative threshold voltage shift is smaller for SiO2 at lower oxidation temperature. Gate bias during irradiation leads to different VTH shift for different gate dielectrics. Single SiO2 layer shows the worst negative VTH at VG=0 V, while double Si3N4/SiO2 shows negative VTH shift at VG=-5 V, positive VTH shift at VG=10 V, and negligible VTH shift at VG=0 V.

  10. Create Your Plate

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  12. Create Your Plate

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  13. Create Your Plate

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    Full Text Available ... Planning Meals > Create Your Plate Share: Print Page Text Size: A A A Listen En Español Create ... Type 2 Education Series Hear audio clips and full recordings of past Q&A events at your ...

  14. Association behaviour of 241Am(III) on SiO2(amorphous) and SiO2(quartz) colloids

    International Nuclear Information System (INIS)

    Degueldre, C.; Wernli, B.

    1993-01-01

    SiO 2 colloids have been identified as a potential vector for enhancing radionuclide transport in granitic groundwater and in concrete pore water. The sorption behaviour of 241 Am(III) on SiO 2 colloids was studied as a function of americium concentration pH (5-12), colloid concentration, ionic strength, temperature and SiO 2 allotropic species. The Am(III) sorption mechanism on amorphous silica is different from that on quartz. For SiO 2(amorphous) solution, the variation of log K p (ml g -1 ) with pH is linear (pH=5-9) with a slope of +1 indicating a one proton exchange mechanism. The colloid concentration (ppm) affects the sorption and log K p 3.7-0.67 log [SiO 2 ] (pH = 6). K p increases insignificantly when the ionic strength decreases. It shows no significant variation, however, with the Am concentration. On amorphous silica, the Am(III) sorption is driven by proton exchange from the silanol groups. For SiO 2 (quartz), log K p is constant over a large range of quartz concentration in suspension and the variation of log K p with pH is about linear (pH = 5-12), with a slope of 0.28, indicating a more complex exchange mechanism. Reactions taking into account the interaction of positive Am(OH) w (3-w)+ species on to the negatively charged quartz surface are suggested. (author)

  15. Diffusive charge transport in graphene on SiO 2

    Science.gov (United States)

    Chen, J.-H.; Jang, C.; Ishigami, M.; Xiao, S.; Cullen, W. G.; Williams, E. D.; Fuhrer, M. S.

    2009-07-01

    We review our recent work on the physical mechanisms limiting the mobility of graphene on SiO 2. We have used intentional addition of charged scattering impurities and systematic variation of the dielectric environment to differentiate the effects of charged impurities and short-range scatterers. The results show that charged impurities indeed lead to a conductivity linear in density ( σ(n)∝n) in graphene, with a scattering magnitude that agrees quantitatively with theoretical estimates; increased dielectric screening reduces the scattering from charged impurities, but increases the scattering from short-range scatterers. We evaluate the effects of the corrugations (ripples) of graphene on SiO 2 on transport by measuring the height-height correlation function. The results show that the corrugations cannot mimic long-range (charged impurity) scattering effects, and have too small an amplitude-to-wavelength ratio to significantly affect the observed mobility via short-range scattering. Temperature-dependent measurements show that longitudinal acoustic phonons in graphene produce a resistivity that is linear in temperature and independent of carrier density; at higher temperatures, polar optical phonons of the SiO 2 substrate give rise to an activated, carrier density-dependent resistivity. Together the results paint a complete picture of charge carrier transport in graphene on SiO 2 in the diffusive regime.

  16. Creating more effective graphs

    CERN Document Server

    Robbins, Naomi B

    2012-01-01

    A succinct and highly readable guide to creating effective graphs The right graph can be a powerful tool for communicating information, improving a presentation, or conveying your point in print. If your professional endeavors call for you to present data graphically, here's a book that can help you do it more effectively. Creating More Effective Graphs gives you the basic knowledge and techniques required to choose and create appropriate graphs for a broad range of applications. Using real-world examples everyone can relate to, the author draws on her years of experience in gr

  17. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.

    2013-12-29

    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir\\'s model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO2/silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15. © Bangladesh Uni. of Engg. & Tech.

  18. Create Your Plate

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    Full Text Available ... Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate en -- A Future Without Diabetes - a- ...

  19. Create Your Plate

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    Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart- ...

  20. Create Your Plate

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    Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

  1. Create Your Plate

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    Full Text Available ... Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning ... serving of dairy or both as your meal plan allows. Choose healthy fats in small amounts. For ...

  2. Create Your Plate

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    Full Text Available ... Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ...

  3. Create Your Plate

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    Full Text Available ... Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get Started Safely Get And ... Plate Create Your Plate is a simple and effective way to manage your blood glucose levels and ...

  4. Create Your Plate

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    Full Text Available ... Us in the Fight for a Cure Your tax-deductible gift today can fund critical diabetes research ... Close www.diabetes.org > Food and Fitness > Food > Planning Meals > Create Your Plate Share: Print Page Text ...

  5. Create Your Plate

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    Full Text Available ... critical diabetes research and support vital diabetes education services that improve the lives of those with diabetes. $50 $100 $250 $500 Other Other Ways ... Meals > Create Your Plate ...

  6. Create Your Plate

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    Full Text Available ... Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with ... Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy ...

  7. Create Your Plate

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    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  8. Argon-plasma-controlled optical reset in the SiO2/Cu filamentary resistive memory stack

    Science.gov (United States)

    Kawashima, T.; Yew, K. S.; Zhou, Y.; Ang, D. S.; Zhang, H. Z.; Kyuno, K.

    2018-05-01

    We show that resistive switching in the SiO2/Cu stack can be modified by a brief exposure of the oxide to an Ar plasma. The set voltage of the SiO2/Cu stack is reduced by 33%, while the breakdown voltage of the SiO2/Si stack (control) is almost unchanged. Besides, the Ar plasma treatment suppresses the negative photoconductivity or optical resistance reset effect, where the electrically formed filamentary conductive path consisting of Cu-ion and oxygen-vacancy clusters is disrupted by the recombination of the oxygen vacancies with nearby light-excited oxygen ions. From the enhanced O-H peak in the Fourier-transform infrared spectrum of the plasma-treated oxide, it is proposed that the Ar plasma has created more oxygen vacancies in the surface region of the oxide. These vacancies in turn adsorb water molecules, which act as counter anions (OH-) promoting the migration of Cu cations into the oxide and forming a more complete Cu filament that is less responsive to light. The finding points to the prospect of a control over the optical resistance reset effect by a simple surface treatment step.

  9. Report on progress in creating the internal gas and electricity market. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions

    International Nuclear Information System (INIS)

    2010-01-01

    In late 2008 and 2009, the world was hit by the financial and economic crisis. This had a direct impact on the demand for energy, causing unpredicted falls in the price of oil on the international markets. This, in turn, impacted on gas and electricity prices. A dispute between two companies outside the EU (Gazprom of Russia and Naftogaz of Ukraine) led to an unprecedented crisis in the EU's gas supply. Between 6 and 20 January 2009, gas flows from Russia to the EU via Ukraine were interrupted, affecting several Member States. 2009 was also an important year because the third internal energy market package was adopted on 13 July 2009. The third package strengthens the regulatory framework that is needed in order to make market opening fully effective, in the interest of achieving the lowest possible energy prices, better energy security and sustainability. This report discusses how the developments described above have impacted on the EU electricity and gas markets over the past year and how they are likely to affect market developments in the future.

  10. Incorporation of sol-gel SnO2:Sb into nanoporous SiO2

    International Nuclear Information System (INIS)

    Canut, B.; Blanchin, M.G.; Ramos-Canut, S.; Teodorescu, V.; Toulemonde, M.

    2006-01-01

    Silicon oxide films thermally grown on Si(1 0 0) wafers were irradiated with 200 MeV 197 Au ions in the 10 9 -10 1 cm -2 fluence range. The targets were then etched at room temperature in aqueous HF solution (1 vol.%) for various durations. Atomic force microscopy (AFM) in the tapping mode was used to probe the processed surfaces. Conical holes with a low size dispersion were evidenced. Their surface diameter varies between 20 and 70 nm, depending on the etching time. Sol-gel dip coating technique, associated with a further annealing treatment performed at 500 o C for 15 min, was used to fill the nanopores created in SiO 2 with a transparent conductive oxide (SnO 2 doped with antimony). Transmission electron microscopy (TEM) performed on cross-sectional specimen showed that SnO 2 :Sb crystallites of ∼5 nm mean size are trapped in the holes without degrading their geometry

  11. Photoemission study on electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces

    International Nuclear Information System (INIS)

    Fujimura, Nobuyuki; Ohta, Akio; Ikeda, Mitsuhisa; Makihara, Katsunori; Miyazaki, Seiichi

    2017-01-01

    Electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces have been investigated by X-ray photoelectron spectroscopy (XPS) under monochromatized Al Kα radiation. From the analysis of the cut-off energy for secondary photoelectrons measured at each thinning step of a dielectric layer by wet-chemical etching, an abrupt potential change caused by electrical dipole at SiO_2/Si and HfO_2/SiO_2 interfaces has been clearly detected. Al-gate MOS capacitors with thermally-grown SiO_2 and a HfO_2/SiO_2 dielectric stack were fabricated to evaluate the Al work function from the flat band voltage shift of capacitance-voltage (C-V) characteristics. Comparing the results of XPS and C-V measurements, we have verified that electrical dipole formed at the interface can be directly measured by photoemission measurements. (author)

  12. Ordered micro/macro porous K-OMS-2/SiO2 nanocatalysts: Facile synthesis, low cost and high catalytic activity for diesel soot combustion

    Science.gov (United States)

    Yu, Xuehua; Zhao, Zhen; Wei, Yuechang; Liu, Jian

    2017-04-01

    A series of novel oxide catalysts, which contain three-dimensionally ordered macroporous (3DOM) and microporous structure, were firstly designed and successfully synthesized by simple method. In the as-prepared catalysts, 3DOM SiO2 is used as support and microporous K-OMS-2 oxide nanoparticles are supported on the wall of SiO2. 3DOM K-OMS-2/SiO2 oxide catalysts were firstly used in soot particle oxidation reaction and they show very high catalytic activities. The high activities of K-OMS-2/SiO2 oxide catalysts can be assigned to three possible reasons: macroporous effect of 3DOM structure for improving contact between soot and catalyst, microporous effect of K-OMS-2 for adsorption of small gas molecules and interaction of K and Mn for activation of gas molecules. The catalytic activities of catalysts are comparable to or even higher than noble metal catalyst in the medium and high temperature range. For example, the T50 of K-OMS-2/SiO2-50, 328 °C, is much lower than those of Pt/Al2O3 and 3DOM Au/LaFeO3, 464 and 356 °C,respectively. Moreover, catalysts exhibited high catalytic stability. It is attributed to that the K+ ions are introduced into the microporous structure of OMS-2 and stabilized in the catalytic reaction. Meanwhile, the K+ ions play an important role in templating and stabilizing the tunneled framework of OMS-2.

  13. LOW-VELOCITY SHOCKS TRACED BY EXTENDED SiO EMISSION ALONG THE W43 RIDGES: WITNESSING THE FORMATION OF YOUNG MASSIVE CLUSTERS

    International Nuclear Information System (INIS)

    Nguyen-Luong, Q.; Martin, P. G.; Motte, F.; Louvet, F.; Hill, T.; Hennemann, M.; Didelon, P.; Carlhoff, P.; Schilke, P.; Lesaffre, P.; Gusdorf, A.; Schneider, N.; Bontemps, S.; Duarte-Cabral, A.; Menten, K. M.; Wyrowski, F.; Bendo, G.; Roussel, H.; Bernard, J.-P.; Bronfman, L.

    2013-01-01

    The formation of high-mass stars is tightly linked to that of their parental clouds. Here, we focus on the high-density parts of W43, a molecular cloud undergoing an efficient event of star formation. Using a column density image derived from Herschel continuum maps, we identify two high-density filamentary clouds, called the W43-MM1 and W43-MM2 ridges. Both have gas masses of 2.1 × 10 4 M ☉ and 3.5 × 10 4 M ☉ above >10 23 cm -2 and within areas of ∼6 and ∼14 pc 2 , respectively. The W43-MM1 and W43-MM2 ridges are structures that are coherent in velocity and gravitationally bound, despite their large velocity dispersion measured by the N 2 H + (1-0) lines of the W43-HERO IRAM large program. Another intriguing result is that these ridges harbor widespread (∼10 pc 2 ) bright SiO (2-1) emission, which we interpret to be the result of low-velocity shocks (≤10 km s –1 ). We measure a significant relationship between the SiO (2-1) luminosity and velocity extent and show that it distinguishes our observations from the high-velocity shocks associated with outflows. We use state-of-the-art shock models to demonstrate that a small percentage (10%) of Si atoms in low-velocity shocks, observed initially in gas phase or in grain mantles, can explain the observed SiO column density in the W43 ridges. The spatial and velocity overlaps between the ridges of high-density gas and the shocked SiO gas suggest that ridges could be forming via colliding flows driven by gravity and accompanied by low-velocity shocks. This mechanism may be the initial conditions for the formation of young massive clusters

  14. Creating organizational cultures

    DEFF Research Database (Denmark)

    Mouton, Nicolaas T.O.; Just, Sine Nørholm; Gabrielsen, Jonas

    2012-01-01

    Purpose – The purpose of this paper is to re-conceptualize the relations between rhetorical strategies and material practices in the processes whereby leaders create or change organizational cultures. Design/methodology/approach – The authors compare and contrast two broad perspectives on cultural...... insights. The authors propose an integrated perspective in which material practices and rhetorical strategies are seen as two analytical sides of the same ontological coin. This enables a fuller and more detailed explanation of how organizational cultures are created or changed. A brief illustration...

  15. Creating Web Pages Simplified

    CERN Document Server

    Wooldridge, Mike

    2011-01-01

    The easiest way to learn how to create a Web page for your family or organization Do you want to share photos and family lore with relatives far away? Have you been put in charge of communication for your neighborhood group or nonprofit organization? A Web page is the way to get the word out, and Creating Web Pages Simplified offers an easy, visual way to learn how to build one. Full-color illustrations and concise instructions take you through all phases of Web publishing, from laying out and formatting text to enlivening pages with graphics and animation. This easy-to-follow visual guide sho

  16. Create Your Plate

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    Full Text Available ... meal-planning, . In this section Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate en -- A Future Without Diabetes - a-future-without-diabetes-2.html A Future ...

  17. Creating Customer Delight.

    Science.gov (United States)

    Black, Jim

    1995-01-01

    This article proposes that college admissions officers interested in improving service should focus on creating customer delight rather than simply satisfaction, studying the system when things go wrong rather than placing blame, establishing employee well-being as the highest priority of the organization, providing necessary tools and training…

  18. Create Your Plate

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    Full Text Available ... tool is not to scale because of the differences in types of vegetables. When creating your plate ... function (data) { $('#survey-errors').remove(); $('.survey-form .form-group .survey-alert-wrap').remove(); if (data.submitSurveyResponse.success == ' ...

  19. Creating Pupils' Internet Magazine

    Science.gov (United States)

    Bognar, Branko; Šimic, Vesna

    2014-01-01

    This article presents an action research, which aimed to improve pupils' literary creativity and enable them to use computers connected to the internet. The study was conducted in a small district village school in Croatia. Creating a pupils' internet magazine appeared to be an excellent way for achieving the educational aims of almost all…

  20. Creating a Classroom Makerspace

    Science.gov (United States)

    Rivas, Luz

    2014-01-01

    What is a makerspace? Makerspaces are community-operated physical spaces where people (makers) create do-it-yourself projects together. These membership spaces serve as community labs where people learn together and collaborate on projects. Makerspaces often have tools and equipment like 3-D printers, laser cutters, and soldering irons.…

  1. Create Your Plate

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    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  2. Creating White Australia

    DEFF Research Database (Denmark)

    McLisky, Claire Louise; Carey, Jane

    Vedtagelsen af White Australien som regeringens politik i 1901 viser, at hvidheden var afgørende for den måde, hvorpå den nye nation i Australien blev konstitueret. Og alligevel har historikere i vid udstrækning overset hvidhed i deres studier af Australiens race fortid. 'Creating White Australia...

  3. Creating Innovative Opportunities

    DEFF Research Database (Denmark)

    Ljungberg, Daniel; McKelvey, Maureen; Lassen, Astrid Heidemann

    2012-01-01

    This paper develops lessons about how and why the founders and ventures involved in knowledge intensive entrepreneurship (KIE) manage the process of venture creation. The meta-analysis of the 86 case studies is based upon as conceptual model (from a systemic literature review), linked to illustra...... of knowledge networks to create innovative opportunities....

  4. Create Your State

    Science.gov (United States)

    Dunham, Kris; Melvin, Samantha

    2011-01-01

    Students are often encouraged to work together with their classmates, sometimes with other classes, occasionally with kids at other schools, but rarely with kids across the country. In this article the authors describe the Create Your State project, a collaborative nationwide project inspired by the Texas Chair Project wherein the artist, Damien…

  5. Creating a Third Culture

    Science.gov (United States)

    Weisbuch, Robert A.

    2008-01-01

    In this article, the author laments higher education's lack of concern towards the development of teaching in the public schools over the last half of the 20th century. Most of academe's work on the topic of teacher training has been done at the branches of state universities that needed to make money and create a niche. The author observes that…

  6. Synthesis of metallic nanoparticles in SiO2 matrices

    International Nuclear Information System (INIS)

    Gutierrez W, C.; Mondragon G, G.; Perez H, R.; Mendoza A, D.

    2004-01-01

    Metallic nanoparticles was synthesized in SiO 2 matrices by means of a process of two stages. The first one proceeded via sol-gel, incorporating the metallic precursors to the reaction system before the solidification of the matrix. Later on, the samples underwent a thermal treatment in atmosphere of H 2 , carrying out the reduction of the metals that finally formed to the nanoparticles. Then it was detected the presence of smaller nanoparticles than 20 nm, dispersed and with the property of being liberated easily of the matrix, conserving a free surface, chemically reactive and with response to external electromagnetic radiation. The system SiO 2 -Pd showed an important thermoluminescent response. (Author)

  7. Luminescence characteristics of Mg2SiO4:Nd

    International Nuclear Information System (INIS)

    Indira, P.; Subrahmanyam, R.V.; Murthy, K.V.R.

    2011-01-01

    Thermoluminescence (TL) properties of Magnesium Ortho silicate (2:1) Mg 2 SiO 4 doped with various concentrations of rare earth (Nd) have been studied. The phosphor material were prepared using standard solid state reaction technique and heated specimens at 1100 ± 20 deg C for two hours. 4% Ammonium chloride was used as flux. The received material was grinded in an agate mortar and pestle. The TL exhibited by the Mg 2 SiO 4 with varying concentration of Nd is interesting in nature. It is interesting to note but as the concentration of Nd increases the peak around 125 deg C TL peak intensity increases. But the hump around 200 deg C resolved as TL peak at 253 deg C with high intensity. (author)

  8. AGOR 28: SIO Shipyard Representative Bi-Weekly Progress Report

    Science.gov (United States)

    2016-02-15

    Handles for Bridge port and stbd side sliding windows reinstalled with better adhesive. Should be good now. Have to remember to lift up on...handle before attempting to slide. Woody has expressed concern with potential interference of ships main crane and CAST 6 winches. SIO plans to...swap forward CTD handling arm with the after overboarding arm. This may exacerbate potential interferences with stowed crane . A possible solution

  9. Optical transparency and mechanical properties of semi-refined iota carrageenan film reinforced with SiO2 as food packaging material

    Science.gov (United States)

    Aji, Afifah Iswara; Praseptiangga, Danar; Rochima, Emma; Joni, I. Made; Panatarani, Camellia

    2018-02-01

    Food packaging is important for protecting food from environmental influences such as heat, light, water vapor, oxygen, dirt, dust particles, gas emissions and so on, which leads to decrease the quality of food. The most widely used type of packaging in the food industry is plastic which is made from synthetic polymers and takes hundreds of years to biodegrade. Recently, food packaging with high bio-degradability is being developed using biopolymer combined with nanoparticles as reinforcing agent (filler) to improve its properties. In this study, semi-refined iota carrageenan films were prepared by incorporating SiO2 nanoparticles as filler at different concentrations (0%, 0.5%, 1.0% and 1.5% w/w carrageenan) using solution casting method. The optical transparency and mechanical properties (tensile strength and elongation at break) of the films were analyzed. The results showed that incorporation of SiO2 nanoparticles to carrageenan matrix on optical transparency of the films. For the mechanical properties, the highest tensile strength was found for incorporation of 0.5% SiO2, while the elongation at break of the films improved with increasing SiO2 concentration.

  10. Adsorption of uranyl in SiO2 porous glass

    International Nuclear Information System (INIS)

    Benedetto, F. E.; Prado, M. O.

    2013-01-01

    Vitreous SiO 2 porous matrices can be used in many applications involving the uptake of chemical species on its solid surface. In this work, vitreous silica sponges were prepared from a sodium borosilicate glass manufactured in our laboratory. The product obtained was then separated into phases with subsequent leaching of the soluble phase rich in B and Na. The resulting porous matrices have a specific surface of 35 m2/gr. Adsorption of uranyl ions onto the SiO 2 porous surface was studied to evaluate the use of this material as a filter for treatment of uranium containing water. The effects of contact time, adsorbent mass and equilibrium concentration of solution were studied. The porous adsorbent exhibits a pseudo-second-order kinetic behavior. The sponges with adsorbed uranium were thermally sealed as a way of U immobilization. Retention of uranium was confirmed during the matrix sealing by TGA. Uranium concentration before and after adsorption tests were made by means of ICP-OES. For uranium concentration of 800 ppm, 72 hours contact time and pH of 3.5, the amount of uranium adsorbed was 21.06 ± 0.02 mg U per gram of vitreous porous SiO 2 . (author)

  11. Design Of A Bi-Functional α-Fe2O3/Zn2SiO4:Mn2+ By Layer-By-Layer Assembly Method

    Directory of Open Access Journals (Sweden)

    Yu Ri

    2015-06-01

    Full Text Available This work describes the design of bi-functional α-Fe2O3/Zn2SiO4:Mn2+ using a two-step coating process. We propose a combination of pigments (α-Fe2O3 and phosphor (Zn2SiO4:Mn2+ glaze which is assembled using a layer-by-layer method. A silica-coated α-Fe2O3 pigment was obtained by a sol-gel method and a Zn2+ precursor was then added to the silica-coated α-Fe2O3 to create a ZnO layer. Finally, the Zn2SiO4:Mn2+ layer was prepared with the addition of Mn2+ ions to serve as a phosphor precursor in the multi-coated α-Fe2O3, followed by annealing at a temperature above 1000°C. Details of the phase structure, color and optical properties of the multi-functional α-Fe2O3/Zn2SiO4:Mn2+ were characterized by transmission electron microscopy and X-ray diffraction analyses.

  12. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  13. Creating resilient SMEs

    DEFF Research Database (Denmark)

    Dahlberg, Rasmus; Guay, Fanny

    2015-01-01

    According to the EU, during the past five years, small and medium enterprises (SMEs) have created 85% of new jobs and two-thirds of private sector employment in the region. SMEs are considered the backbone of the economy in Europe and represent more than 95% of enterprises in USA and Australia....... They are considered more vulnerable to disasters because of their size. This paper argues, on the contrary, that SMEs also can be less vulnerable to sudden change than large corporations, drawing upon the ideas of Hayek and Taleb, and that networks of SMEs may contribute to the overall resilience of society...... if certain criteria are met. With this in mind, this paper will be examining how to create resilient SMEs. A well-known concept in the field is business continuity management. BCM is defined as “a holistic management process that identifies potential threats to an organization and the impacts to business...

  14. Effect of Commercial SiO2 and SiO2 from rice husk ash loading on biodegradation of Poly (lactic acid) and crosslinked Poly (lactic acid)

    Science.gov (United States)

    Prapruddivongs, C.; Apichartsitporn, M.; Wongpreedee, T.

    2017-09-01

    In this work, biodegradation behavior of poly (lactic acid) (PLA) and crosslinked PLA filled with two types of SiO2, precipitated SiO2 (commercial SiO2) and SiO2 from rice husk ash, were studied. Rice husks were first treated with 2 molar hydrochloric acid (HCl) to produce high purity SiO2, before burnt in a furnace at 800°C for 6 hours. All components were melted bending by an internal mixer then hot pressed using compression molder to form tested specimens. FTIR spectra of SiO2 and PLA samples were investigated. The results showed the lack of silanol group (Si-OH) of rice husk ash after steric acid surface modification, while the addition of particles can affect the crosslinking of the PLA. For biodegradation test by evaluating total amount of carbon dioxide (CO2) evolved during 60 days incubation at a controlled temperature of 58±2°C, the results showed that the biodegradation of crosslinked PLA occurred slower than the neat PLA. However, SiO2 incorporation enhanced the degree of biodegradation In particular, introducing commercial SiO2 in PLA and crosslinked PLA tended to clearly increase the degree of biodegradation as a consequence of the more accelerated hydrolysis degradation.

  15. Photoluminescence analysis of Ce3+:Zn2SiO4 & Li++ Ce3+:Zn2SiO4: phosphors by a sol-gel method

    Science.gov (United States)

    Babu, B. Chandra; Vandana, C. Sai; Guravamma, J.; Rudramadevi, B. Hemalatha; Buddhudu, S.

    2015-06-01

    Here, we report on the development and photoluminescence analysis of Zn2SiO4, Ce3+:Zn2SiO4 & Li+ + Ce3+: Zn2SiO4 novel powder phosphors prepared by a sol-gel technique. The total amount of Ce3+ ions was kept constant in this experiment at 0.05 mol% total doping. The excitation and emission spectra of undoped (Zn2SiO4) and Ce3+ doped Zn2SiO4 and 0.05 mol% Li+ co-doped samples have been investigated. Cerium doped Zn2SiO4 powder phosphors had broad blue emission corresponding to the 2D3/2→2FJ transition at 443nm. Stable green-yellow-red emission has been observed from Zn2SiO4 host matrix and also we have been observed the enhanced luminescence of Li+ co-doped Zn2SiO4:Ce3+. Excitation and emission spectra of these blue luminescent phosphors have been analyzed in evaluating their potential as luminescent screen coating phosphors.

  16. Creating flat design websites

    CERN Document Server

    Pratas, Antonio

    2014-01-01

    This book contains practical, step-by-step tutorials along with plenty of explanation about designing your flat website. Each section is introduced sequentially, building up your web design skills and completing your website.Creating Flat Design Websites is ideal for you if you are starting on your web development journey, but this book will also benefit seasoned developers wanting to start developing in flat.

  17. Preliminary study in development of glass-ceramic based on SiO2-LiO2 system, starting of different SiO2 starting powders

    International Nuclear Information System (INIS)

    Daguano, J.K.M.F.; Santos, F.A.; Santos, C.; Marton, L.F.M.; Conte, R.A.; Rodrigues Junior, D.; Melo, F.C.L.

    2009-01-01

    In this work, lithium disilicate glass-ceramics were developed starting of the rice ash- SiO 2 and Li 2 CO 3 powders. The results were compared with glass ceramics based on the lithium disilicate obtained by commercial SiO 2 powders. Glass were melted at 1580 deg C, and annealed at 850 deg C. X-Ray diffraction and scanning electron microscopy were used for characterization of the materials, and hardness and fracture toughness were evaluated using Vickers indentation method. Glasses with amorphous structure were obtained in both materials. After annealing, 'rice-ash' samples presented Li 2 SiO 3 and residual SiO 2 as crystalline phases. On the other side, commercial SiO 2 - Samples presented only Li 2 Si 2 O 5 as crystalline phases and the better results of hardness and fracture toughness. (author)

  18. Physical and Electrical Properties of SiO2 Layer Synthesized by Eco-Friendly Method

    Science.gov (United States)

    Kim, Jong-Woong; Kim, Young-Seok; Hong, Sung-Jei; Hong, Tae-Hwan; Han, Jeong-In

    2010-05-01

    SiO2 thin film has a wide range of applications, including insulation layers in microelectronic devices, such as semiconductors and flat panel displays, due to its advantageous characteristics. Herein, we developed a new eco-friendly method for manufacturing SiO2 nanoparticles and, thereby, SiO2 paste to be used in the digital printing process for the fabrication of SiO2 film. By excluding harmful Cl- and NO3- elements from the SiO2 nanoparticle synthetic process, we were able to lower the heat treatment temperature for the SiO2 precursor from 600 to 300 °C and the diameter of the final SiO2 nanoparticles to about 14 nm. The synthesized SiO2 nanoparticles were dispersed in an organic solvent with additives to make a SiO2 paste for feasibility testing. The SiO2 paste was printed onto a glass substrate to test the feasibility of using it for digital printing. The insulation resistance of the printed film was high enough for it to be used as an insulation layer for passivation.

  19. Creating Two-Dimensional Electron Gas in Nonpolar/Nonpolar Oxide Interface via Polarization Discontinuity: First-Principles Analysis of CaZrO3/SrTiO3 Heterostructure.

    Science.gov (United States)

    Nazir, Safdar; Cheng, Jianli; Yang, Kesong

    2016-01-13

    We studied strain-induced polarization and resulting conductivity in the nonpolar/nonpolar CaZrO3/SrTiO3 (CZO/STO) heterostructure (HS) system by means of first-principles electronic structure calculations. By modeling four types of CZO/STO HS-based slab systems, i.e., TiO2/CaO and SrO/ZrO2 interface models with CaO and ZrO2 surface terminations in each model separately, we found that the lattice-mismatch-induced compressive strain leads to a strong polarization in the CZO film and that as the CZO film thickness increases there exists an insulator-to-metal transition. The polarization direction and critical thickness of the CZO film for forming interfacial metallic states depend on the surface termination of CZO film in both types of interface models. In the TiO2/CaO and SrO/ZrO2 interface models with CaO surface termination, the strong polarization drives the charge transfer from the CZO film to the first few TiO2 layers in the STO substrate, leading to the formation of two-dimensional electron gas (2DEG) at the interface. In the HS models with ZrO2 surface termination, two polarization domains with opposite directions are in the CZO film, which results in the charge transfer from the middle CZO layer to the interface and surface, respectively, leading to the coexistence of the 2DEG on the interface and the two-dimensional hole gas (2DHG) at the middle CZO layer. These findings open a new avenue to achieve 2DEG (2DHG) in perovskite-based HS systems via polarization discontinuity.

  20. Creating a practice website.

    Science.gov (United States)

    Downes, P K

    2007-05-26

    A website is a window to the outside world. For a dental practice, it may be the first point of contact for a prospective new patient and will therefore provide them with their 'first impression'; this may be days or weeks before actually visiting the practice. This section considers the different ways of creating a dental practice website and lists some of the main dental website design companies. It also describes what factors make a successful website and offers advice on how to ensure that it complies with current regulations and recommendations.

  1. The application of Cu/SiO2 catalytic system in chemical mechanical planarization based on the stability of SiO2 sol

    International Nuclear Information System (INIS)

    Li Yan; Liu Yuling; Wang Aochen; Yang Zhixin; Sun Mingbin; Cheng Chuan; Zhang Yufeng; Zhang Nannan

    2014-01-01

    through the removal rate of copper film, infrared spectrum and AFM diagrams in different pH conditions. Finally it is concluded that the SiO 2 sol used in the experiment possesses stable performance; in the CMP process it is directly involved in the chemical reaction by creating the intermediate of the catalytic reaction (CuSiO 3 ) whose yield is proportional to the pH value, which accelerates the removal of copper film. (semiconductor technology)

  2. Surface spins disorder in uncoated and SiO2 coated maghemite nanoparticles

    International Nuclear Information System (INIS)

    Zeb, F.; Nadeem, K.; Shah, S. Kamran Ali; Kamran, M.; Gul, I. Hussain; Ali, L.

    2017-01-01

    We studied the surface spins disorder in uncoated and silica (SiO 2 ) coated maghemite (γ-Fe 2 O 3 ) nanoparticles using temperature and time dependent magnetization. The average crystallite size for SiO 2 coated and uncoated nanoparticles was about 12 and 29 nm, respectively. Scanning electron microscopy (SEM) showed that the nanoparticles are spherical in shape and well separated. Temperature scans of zero field cooled (ZFC)/field cooled (FC) magnetization measurements showed lower average blocking temperature (T B ) for SiO 2 coated maghemite nanoparticles as compared to uncoated nanoparticles. The saturation magnetization (M s ) of SiO 2 coated maghemite nanoparticles was also lower than the uncoated nanoparticles and is attributed to smaller average crystallite size of SiO 2 coated nanoparticles. For saturation magnetization vs. temperature data, Bloch's law (M(T)= M(0).(1− BT b )) was fitted well for both uncoated and SiO 2 coated nanoparticles and yields: B =3×10 −7 K -b , b=2.22 and B=0.0127 K -b , b=0.57 for uncoated and SiO 2 coated nanoparticles, respectively. Higher value of B for SiO 2 coated nanoparticles depicts decrease in exchange coupling due to enhanced surface spins disorder (broken surface bonds) as compared to uncoated nanoparticles. The Bloch's exponent b was decreased for SiO 2 coated nanoparticles which is due to their smaller average crystallite size or finite size effects. Furthermore, a sharp increase of coercivity at low temperatures (<25 K) was observed for SiO 2 coated nanoparticles which is also due to contribution of increased surface anisotropy or frozen surface spins in these smaller nanoparticles. The FC magnetic relaxation data was fitted to stretched exponential law which revealed slower magnetic relaxation for SiO 2 coated nanoparticles. All these measurements revealed smaller average crystallite size and enhanced surface spins disorder in SiO 2 coated nanoparticles than in uncoated γ-Fe 2 O 3 nanoparticles

  3. Photocatalytic hydrogen production using visible-light-responsive Ta 3N5 photocatalyst supported on monodisperse spherical SiO2 particulates

    KAUST Repository

    Liu, Xiaoming

    2014-01-01

    Fine nanoparticles of Ta3N5 (10-20 nm) were synthesized on the surfaces of SiO2 spheres with a diameter of ∼550 nm. A sol-gel method was used to modify the surface of SiO2 with Ta2O5 from TaCl5 dissolved in ethanol in the presence of citric acid and polyethylene glycol. The resulting oxide composites were treated in an NH3 flow at 1123 K to form core-shell structured Ta3N5/SiO2 sub-microspheres. The obtained samples were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDX), transmission electron microscopy (TEM), and photocatalytic activity measurements for H 2 evolution from an aqueous methanol solution. The XRD results demonstrate the expected sequential formation of Ta2O5 layers, followed by Ta3N5 after nitridation on the Ta 2O5/SiO2 composite. SEM and TEM observations indicate that the obtained Ta3N5/SiO2 sub-microspheres have a uniform size distribution with high crystallinity and an obvious core-shell structure. The presence of support maintained the intrinsic photocatalytic activity of Ta3N5 nanoparticles, but it did drastically improve the dispersion of the photocatalysts in the solution. This study proposes the use of an inert support in photocatalytic reactors to improve ease of handling the powder photocatalyst for gas-phase photocatalysis and the suspension of the solution, controlling nature of light harvesting and degree of scattering of the photoreactor. © 2013 Elsevier Ltd. All rights reserved.

  4. Chemical content of the circumstellar envelope of the oxygen-rich AGB star R Doradus. Non-LTE abundance analysis of CO, SiO, and HCN

    Science.gov (United States)

    Van de Sande, M.; Decin, L.; Lombaert, R.; Khouri, T.; de Koter, A.; Wyrowski, F.; De Nutte, R.; Homan, W.

    2018-01-01

    Context. The stellar outflows of low- to intermediate-mass stars are characterised by a rich chemistry. Condensation of molecular gas species into dust grains is a key component in a chain of physical processes that leads to the onset of a stellar wind. In order to improve our understanding of the coupling between the micro-scale chemistry and macro-scale dynamics, we need to retrieve the abundance of molecules throughout the outflow. Aims: Our aim is to determine the radial abundance profile of SiO and HCN throughout the stellar outflow of R Dor, an oxygen-rich AGB star with a low mass-loss rate. SiO is thought to play an essential role in the dust-formation process of oxygen-rich AGB stars. The presence of HCN in an oxygen-rich environment is thought to be due to non-equilibrium chemistry in the inner wind. Methods: We analysed molecular transitions of CO, SiO, and HCN measured with the APEX telescope and all three instruments on the Herschel Space Observatory, together with data available in the literature. Photometric data and the infrared spectrum measured by ISO-SWS were used to constrain the dust component of the outflow. Using both continuum and line radiative transfer methods, a physical envelope model of both gas and dust was established. We performed an analysis of the SiO and HCN molecular transitions in order to calculate their abundances. Results: We have obtained an envelope model that describes the dust and the gas in the outflow, and determined the abundance of SiO and HCN throughout the region of the stellar outflow probed by our molecular data. For SiO, we find that the initial abundance lies between 5.5 × 10-5 and 6.0 × 10-5 with respect to H2. The abundance profile is constant up to 60 ± 10 R∗, after which it declines following a Gaussian profile with an e-folding radius of 3.5 ± 0.5 × 1013 cm or 1.4 ± 0.2 R∗. For HCN, we find an initial abundance of 5.0 × 10-7 with respect to H2. The Gaussian profile that describes the decline

  5. Creating corporate advantage.

    Science.gov (United States)

    Collis, D J; Montgomery, C A

    1998-01-01

    What differentiates truly great corporate strategies from the merely adequate? How can executives at the corporate level create tangible advantage for their businesses that makes the whole more than the sum of the parts? This article presents a comprehensive framework for value creation in the multibusiness company. It addresses the most fundamental questions of corporate strategy: What businesses should a company be in? How should it coordinate activities across businesses? What role should the corporate office play? How should the corporation measure and control performance? Through detailed case studies of Tyco International, Sharp, the Newell Company, and Saatchi and Saatchi, the authors demonstrate that the answers to all those questions are driven largely by the nature of a company's special resources--its assets, skills, and capabilities. These range along a continuum from the highly specialized at one end to the very general at the other. A corporation's location on the continuum constrains the set of businesses it should compete in and limits its choices about the design of its organization. Applying the framework, the authors point out the common mistakes that result from misaligned corporate strategies. Companies mistakenly enter businesses based on similarities in products rather than the resources that contribute to competitive advantage in each business. Instead of tailoring organizational structures and systems to the needs of a particular strategy, they create plain-vanilla corporate offices and infrastructures. The company examples demonstrate that one size does not fit all. One can find great corporate strategies all along the continuum.

  6. Creating sustainable performance.

    Science.gov (United States)

    Spreitzer, Gretchen; Porath, Christine

    2012-01-01

    What makes for sustainable individual and organizational performance? Employees who are thriving-not just satisfied and productive but also engaged in creating the future. The authors found that people who fit this description demonstrated 16% better overall performance, 125% less burnout, 32% more commitment to the organization, and 46% more job satisfaction than their peers. Thriving has two components: vitality, or the sense of being alive and excited, and learning, or the growth that comes from gaining knowledge and skills. Some people naturally build vitality and learning into their jobs, but most employees are influenced by their environment. Four mechanisms, none of which requires heroic effort or major resources, create the conditions for thriving: providing decision-making discretion, sharing information about the organization and its strategy, minimizing incivility, and offering performance feedback. Organizations such as Alaska Airlines, Zingerman's, Quicken Loans, and Caiman Consulting have found that helping people grow and remain energized at work is valiant on its own merits-but it can also boost performance in a sustainable way.

  7. Photocatalytic degradation of mixed gaseous carbonyl compounds at low level on adsorptive TiO2/SiO2 photocatalyst using a fluidized bed reactor.

    Science.gov (United States)

    Zhang, Maolin; An, Taicheng; Fu, Jiamo; Sheng, Guoying; Wang, Xinming; Hu, Xiaohong; Ding, Xuejun

    2006-06-01

    An adsorptive silica-supported titania photocatalyst TiO(2)/SiO(2) was prepared by using nanosized titania (anatase) immobilized on silica gel by the sol-gel technique with the titanium tetra isopropoxide as the main raw material and acetic acid as the acid catalyst. Meanwhile the structure and properties of the TiO(2)/SiO(2) photocatalyst were studied by means of many modern analysis techniques such as TEM, XRD, and BET. Gas-solid heterogeneous photocatalytic decomposition of four carbonyl compounds mixture at low concentration levels over ultraviolet irradiated TiO(2)/SiO(2) photocatalyst were carried out with high degradation efficiencies in a coaxial triple-cylinder-type fluidized bed photocatalytic reactor, which provided efficient continuous contact of ultraviolet photons, silica-supported titania photocatalyst, and gaseous reactants. Experimental results showed that the photocatalyst had a high adsorption performance and a good photocatalytic activity for four carbonyl compounds mixture. Some factors influencing the photocatalytic decomposition of the mixed carbonyl compounds, i.e. the gas flowrate, relative humidity, concentration of oxygen, and illumination time, were discussed in detail. It is found that the photocatalytic reaction rate of four carbonyl compounds decreased in this order: propionaldehyde, acetone, acetaldehyde and formaldehyde.

  8. Simpósio de Geoarqueologia: temas abordados e resultados

    OpenAIRE

    Silva, Rosiclér Theodoro da; Tizuka, Michelle Mayumi; López, Carlos E.; Favier-Dubois, Cristian M.; Kashimoto, Emília Mariko; Rubin, Julio Cezar Rubin de; Brochier, Laercio Loiola; Barberi, Maira; Rodet, Maria Jacqueline; Afonso, Marisa Coutinho; Cano, Martha Cecilia; Santos, Nicali Bleyer Ferreira dos; Kipnis, Renato; Tatumi, Sonia Hatsui

    2015-01-01

    Resumo: o Simpósio de Geoarqueologia da VI TAAS, coordenado por Rosiclér Theodoro da Silva e Michelle Mayumi Tizuka contou com a apresentação de nove trabalhos de pesquisadores do Brasil, Argentina e Colômbia. Este artigo trata de uma síntese dos temas abordados incluídos em: arqueologia e eventos climáticos, arqueologia e regiões costeiras, arqueologia da paisagem, arqueoestratigrafia, geoarqueologia de sistemas fluviais, arqueologia e vulcanismo. Seu objetivo principal é d...

  9. Creating With Carbon

    Science.gov (United States)

    2003-01-01

    A subsidiary of SI Diamond Technology, Inc., Applied Nanotech, of Austin, Texas, is creating a buzz among various technology firms and venture capital groups interested in the company s progressive research on carbon-related field emission devices, including carbon nanotubes, filaments of pure carbon less than one ten-thousandth the width of human hair. Since their discovery in 1991, carbon nanotubes have gained considerable attention due to their unique physical properties. For example, a single perfect carbon nanotube can range from 10 to 100 times stronger than steel, per unit weight. Recent studies also indicate that the nanotubes may be the best heat-conducting material in existence. These properties, combined with the ease of growing thin films or nanotubes by a variety of deposition techniques, make the carbon-based material one of the most desirable for cold field emission cathodes.

  10. Creating the living brand.

    Science.gov (United States)

    Bendapudi, Neeli; Bendapudi, Venkat

    2005-05-01

    It's easy to conclude from the literature and the lore that top-notch customer service is the province of a few luxury companies and that any retailer outside that rarefied atmosphere is condemned to offer mediocre service at best. But even companies that position themselves for the mass market can provide outstanding customer-employee interactions and profit from them, if they train employees to reflect the brand's core values. The authors studied the convenience store industry in depth and focused on two that have developed a devoted following: QuikTrip (QT) and Wawa. Turnover rates at QT and Wawa are 14% and 22% respectively, much lower than the typical rate in retail. The authors found six principles that both firms embrace to create a strong culture of customer service. Know what you're looking for: A focus on candidates' intrinsic traits allows the companies to hire people who will naturally bring the right qualities to the job. Make the most of talent: In mass-market retail, talent is generally viewed as a commodity, but that outlook becomes a self-fulfilling prophesy. Create pride in the brand: Service quality depends directly on employees' attachment to the brand. Build community: Wawa and QT have made concerted efforts to build customer loyalty through a sense of community. Share the business context: Employees need a clear understanding of how their company operates and how it defines success. Satisfy the soul: To win an employee's passionate engagement, a company must meet his or her needs for security, esteem, and justice.

  11. Processing of SiO2 protective layer using HMDS precursor by combustion CVD.

    Science.gov (United States)

    Park, Kyoung-Soo; Kim, Youngman

    2011-08-01

    Hexamethyldisilazane (HMDS, [(CH3)3Si]2NH) was used as a precursor to form SiO2 protective coatings on IN738LC alloys by combustion chemical vapor deposition (CCVD). SEM and XPS showed that the processed coatings were composed mainly of SiO2. The amount of HMDS had the largest effect on the size of the SiO2 agglomerates and the thickness of the deposited coatings. The specimens coated with SiO2 using the 0.05 mol/l HMDS solution showed a significantly higher temperature oxidation resistance than those deposited under other conditions.

  12. Magnetic SiO2/Fe3O4 colloidal crystals

    International Nuclear Information System (INIS)

    Huang, C-K; Hou, C-H; Chen, C-C; Tsai, Y-L; Chang, L-M; Wei, H-S; Hsieh, K-H; Chan, C-H

    2008-01-01

    We proposed a novel technique to fabricate colloidal crystals by using monodisperse SiO 2 coated magnetic Fe 3 O 4 (SiO 2 /Fe 3 O 4 ) microspheres. The magnetic SiO 2 /Fe 3 O 4 microspheres with a diameter of 700 nm were synthesized in the basic condition with ferric sulfate, ferrous sulfate, tartaric acid and tetraethyl orthosilicate (TEOS) in the reaction system. Monodisperse SiO 2 /Fe 3 O 4 superparamagnetic microspheres have been successfully used to fabricate colloidal crystals under the existing magnetic field

  13. Adsorption of cationic dye on a biohybrid SiO2-alginate

    International Nuclear Information System (INIS)

    Barrón Zambrano, J A; Ávila Ortega, A; Muñoz Rodríguez, D; Carrera Figueiras, C; López-Pérez, A J

    2013-01-01

    In this work, a biohybrid material based on SiO 2 -alginate was obtained and its properties of adsorption evaluated using methylene blue as a model dye. The experimental results showed that the biohybrid SiO 2 -alginate has a higher adsorption ability compared to their base compounds (SiO 2 and alginate). Methylene blue adsorption is pH dependent, resulting in a maximum adsorption at pH = 8. The sorption kinetics rate is similar to SiO 2 . Kinetic data were fitted to a model of pseudosecond order. The experimental isotherms fit well the Langmuir model.

  14. Concentration effect of Tm3+ on cathodoluminescence properties of SiO2: Tm3+ and SiO2:Ho3+, Tm3+ systems

    CSIR Research Space (South Africa)

    Dhlamini, MS

    2012-05-01

    Full Text Available .physb.2011.09.091 Concentration effect of Tm3+ on cathodoluminescence properties of SiO2: Tm 3+ and SiO2:Ho 3+, Tm3+ systems M.S. Dhlamini, G.H. Mhlongo, H.C. Swart, O.M. Ntwaeaborwa, K.T. Hillie ABSTRACT: Cathodoluminescence (CL) properties of Si...O2 powders activated with thulium (Tm3+) and holmium (Ho3+) ions prepared by a sol–gel process were investigated. Different molar concentrations of Tm3+ co-doped with Ho3+ were studied. The 460 nm peak was monitored and the influence of the beam...

  15. Formation of SiO2/polytetrafluoroethylene hybrid superhydrophobic coating

    International Nuclear Information System (INIS)

    Zheng Yansheng; He Yi; Qing Yongquan; Zhuo Zhihao; Mo Qian

    2012-01-01

    Highlights: ► The coating showed the water contact angle of 165° and the water sliding angle of 6°. ► The hierarchical structure with the low surface energy leads to surface superhydrophobicity. ► We demonstrated a simple yet efficient approach to preparing superhydrophobic surface. - Abstract: Superhydrophobic coating has been fabricated on the glass substrates with modified SiO 2 sol and polytetrafluoroethylene emulsion through a sol–gel process. SiO 2 sol was modified with γ-glycidoxypropyl trimethoxysilane. The coatings were characterized by water contact angle measurement, Scanning electron microscope, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy and thermal synthetic analysis. The experimental results show that coatings exhibited superhydrophobic and heat-resistant property with a water average contact angle of 156° and sliding angle of 6°, coating has a rough surface with both micro- and nanoscale structures, γ-glycidoxypropyl trimethoxysilane enhanced the hydrophobicity of the coatings. Low surface energy of polymer and special structure of the coatings were responsible for the hydrophobic of the surfaces.

  16. Interactions of atomic hydrogen with amorphous SiO2

    Science.gov (United States)

    Yue, Yunliang; Wang, Jianwei; Zhang, Yuqi; Song, Yu; Zuo, Xu

    2018-03-01

    Dozens of models are investigated by the first-principles calculations to simulate the interactions of an atomic hydrogen with a defect-free random network of amorphous SiO2 (a-SiO2) and oxygen vacancies. A wide variety of stable configurations are discovered due to the disorder of a-SiO2, and their structures, charges, magnetic moments, spin densities, and density of states are calculated. The atomic hydrogen interacts with the defect-free a-SiO2 in positively or negatively charged state, and produces the structures absent in crystalline SiO2. It passivates the neutral oxygen vacancies and generates two neutral hydrogenated E‧ centers with different Si dangling bond projections. Electron spin resonance parameters, including Fermi contacts, and g-tensors, are calculated for these centers. The atomic hydrogen interacts with the positive oxygen vacancies in dimer configuration, and generate four different positive hydrogenated defects, two of which are puckered like the Eγ‧ centers. This research helps to understand the interactions between an atomic hydrogen, and defect-free a-SiO2 and oxygen vacancies, which may generate the hydrogen-complexed defects that play a key role in the degeneration of silicon/silica-based microelectronic devices.

  17. Stability of trapped electrons in SiO2

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Winokur, P.S.; Flament, O.; Leray, J.L.

    1998-01-01

    Electron trapping near the Si/SiO 2 interface plays a crucial role in mitigating the response of MOS devices to ionizing radiation or high-field stress. These electrons offset positive charge due to trapped holes, and can be present at densities exceeding 10 12 cm -2 in the presence of a similar density of trapped positive charge. The nature of the defects that serve as hosts for trapped electrons in the near-interfacial SiO 2 is presently unknown, although there is compelling evidence that these defects are often intimately associated with trapped holes. This association is depicted most directly in the model of Lelis et al., which suggests that trapped electrons and holes occupy opposite sides of a compensated E center in SiO 2 . Charge exchange between electron traps and the Si can occur over a wide range of time scales, depending on the trap depth and location relative to the Si/SiO 2 interface. Here the authors report a detailed study of the stability of electron traps associated with trapped holes near the Si/SiO 2 interface

  18. Creating one planet communities

    International Nuclear Information System (INIS)

    Wilts, R.

    2010-01-01

    This presentation discussed low carbon communities that used a variety of sustainable energy technologies to reduce energy consumption and waste. The presentation was given by a company who has adopted a One Planet framework to ensure the development of zero carbon, zero waste, sustainable communities.The Dockside Green project was awarded North America's highest leadership in energy and environmental design (LEED) score. The community includes a waste biomass plant and an on-site wastewater treatment plant. Excess heat produced by the community's greenhouse gas (GHG) neutral biomass district heating system is sold to neighbouring communities. The BedZED project in the United Kingdom uses a high-density format to support a community living and workspace environment that uses rainwater harvesting, passive solar heating, high performance envelopes, and green roofs. The site includes 40 electric car charging stations. A combined heat and power (CHP) biomass plant provides electricity and hot water to all buildings. Neighbourhood-scale sustainable development is expected to have a significant impact on the ecological footprint of North American cities. Carbon neutral projects in Canada were also listed. tabs., figs.

  19. Creating an outcomes framework.

    Science.gov (United States)

    Doerge, J B

    2000-01-01

    Four constructs used to build a framework for outcomes management for a large midwestern tertiary hospital are described in this article. A system framework outlining a model of clinical integration and population management based in Steven Shortell's work is discussed. This framework includes key definitions of high-risk patients, target groups, populations and community. Roles for each level of population management and how they were implemented in the health care system are described. A point of service framework centered on seven dimensions of care is the next construct applied on each nursing unit. The third construct outlines the framework for role development. Three roles for nursing were created to implement strategies for target groups that are strategic disease categories; two of those roles are described in depth. The philosophy of nursing practice is centered on caring and existential advocacy. The final construct is the modification of the Dartmouth model as a common framework for outcomes. System applications of the scorecard and lessons learned in the 2-year process of implementation are shared

  20. Creating a disability mythology.

    Science.gov (United States)

    Brown, S E

    1992-01-01

    People with disabilities have, for the most part, failed to identify with each other as a group. This has been detrimental because it has built a sense of isolation when a camaraderie based upon existing commonalities could have been developed. During the past ten to twenty years, there has been a great deal of discussion about appropriate language to use when discussing disability issues. This discussion has been a part of a larger debate concerning the existence of a disability culture. I believe that there is indeed a disability culture and I am a proponent of identifying and passing on stories which contribute to that culture. I have chosen to use mythology to convey this message and have begun with a focus on heroes - people who do something out of the ordinary. It is contended that almost all people with disabilities have performed heroic activities because of the pervasive discrimination encountered by each individual with a disability. Creating a disability mythology is an attempt to recognize and promote heroes within the disabled community and to advocate the importance of telling other people how positive change has occurred through instances of individual heroism.

  1. Long lasting yellow phosphorescence and photostimulated luminescence in Sr3SiO5 : Eu2+ and Sr3SiO5 : Eu2+, Dy3+ phosphors

    International Nuclear Information System (INIS)

    Sun Xiaoyuan; Zhang Jiahua; Zhang Xia; Luo Yongshi; Wang Xiaojun

    2008-01-01

    We report the observation of long lasting yellow phosphorescence and photostimulated luminescence (PSL) in Sr 3 SiO 5 : Eu 2+ and Sr 3 SiO 5 : Eu 2+ , Dy 3+ phosphors. The decay patterns of phosphorescence and thermoluminescence curves demonstrate that introduction of Dy 3+ into Sr 3 SiO 5 : Eu 2+ can generate a large number of shallow traps and deep traps. The generated deep traps prolong the phosphorescence up to 6 h after UV irradiation. The PSL is studied under 808 nm excitation. Slow rising and falling edges of the emission in Sr 3 SiO 5 : Eu 2+ , Dy 3+ are observed, showing a retrapping process by the generated shallow traps due to co-doping Dy 3+ .

  2. Low-velocity Shocks Traced by Extended SiO Emission along the W43 Ridges: Witnessing the Formation of Young Massive Clusters

    Science.gov (United States)

    Nguyen-Lu'o'ng, Q.; Motte, F.; Carlhoff, P.; Louvet, F.; Lesaffre, P.; Schilke, P.; Hill, T.; Hennemann, M.; Gusdorf, A.; Didelon, P.; Schneider, N.; Bontemps, S.; Duarte-Cabral, A.; Menten, K. M.; Martin, P. G.; Wyrowski, F.; Bendo, G.; Roussel, H.; Bernard, J.-P.; Bronfman, L.; Henning, T.; Kramer, C.; Heitsch, F.

    2013-10-01

    The formation of high-mass stars is tightly linked to that of their parental clouds. Here, we focus on the high-density parts of W43, a molecular cloud undergoing an efficient event of star formation. Using a column density image derived from Herschel continuum maps, we identify two high-density filamentary clouds, called the W43-MM1 and W43-MM2 ridges. Both have gas masses of 2.1 × 104 M ⊙ and 3.5 × 104 M ⊙ above >10^{23}\\, {{cm}^{-2}} and within areas of ~6 and ~14 pc2, respectively. The W43-MM1 and W43-MM2 ridges are structures that are coherent in velocity and gravitationally bound, despite their large velocity dispersion measured by the N2H+ (1-0) lines of the W43-HERO IRAM large program. Another intriguing result is that these ridges harbor widespread (~10 pc2) bright SiO (2-1) emission, which we interpret to be the result of low-velocity shocks (models to demonstrate that a small percentage (10%) of Si atoms in low-velocity shocks, observed initially in gas phase or in grain mantles, can explain the observed SiO column density in the W43 ridges. The spatial and velocity overlaps between the ridges of high-density gas and the shocked SiO gas suggest that ridges could be forming via colliding flows driven by gravity and accompanied by low-velocity shocks. This mechanism may be the initial conditions for the formation of young massive clusters.

  3. Synthesis of TiO2-doped SiO2 composite films and its applications

    Indian Academy of Sciences (India)

    Wintec

    structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactiv- ity in order to ... gaku D-max γA diffractometer with graphite mono- chromized ... FT–IR absorption spectra of TiO2-doped SiO2 com-.

  4. Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

    Indian Academy of Sciences (India)

    Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres. K C BARICK and D BAHADUR*. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay,. Mumbai 400 076, India. Abstract. The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 ...

  5. Geometry of VY Canis Majoris derived from SiO maser lines

    International Nuclear Information System (INIS)

    Van Blerkom, D.; Auer, L.

    1976-01-01

    A radiation reveals transfer calculation reveals that the SiO maser lines observed in the spectrum of VY CMa are formed in a rotating equatorial disk seen nearly edge-on. Other geometries are considered and eliminated. It is suggested that the SiO lines of NML Cyg also show evidence that they are formed in a disk

  6. Excimer laser crystallization of InGaZnO4 on SiO2 substrate

    NARCIS (Netherlands)

    Chen, T.; Wu, M.Y.; Ishihara, R.; Nomura, K.; Kamiya, T.; Hosono, H.; Beenakker, C.I.M.

    2011-01-01

    In this paper, we were able to crystallize InGaZnO4 (IGZO) by excimer laser on SiO2 substrate. It was observed that uniform [0001] textured polycrystalline IGZO film has been obtained without any grain boundaries and oxygen vacancies on SiO2 substrate. This process is very promising in fabricating

  7. Photoluminescence properties of X5SiO4Cl6:Tb (X = Sr, Ba) green ...

    Indian Academy of Sciences (India)

    attracted more attention due to their potential applications ... materials were thoroughly mixed and ground in an agate mortar. ... Figure 2. Excitation spectra of Ba5SiO4Cl6:Tb3+ phosphor. spectrum of Tb3+ singly doped phosphor Ba5SiO4Cl6,.

  8. Effect of SiO2 addition and gamma irradiation on the lithium borate glasses

    Science.gov (United States)

    Raut, A. P.; Deshpande, V. K.

    2018-01-01

    The physical properties like density, glass transition temperature (Tg), and ionic conductivity of lithium borate (LB) glasses with SiO2 addition were measured before and after gamma irradiation. Remarkable changes in properties have been obtained in the physical properties of LB glasses with SiO2 addition and after gamma irradiation. The increase in density and glass transition temperature of LB glasses with SiO2 addition has been explained with the help of increase in density of cross linking due to SiO4 tetrahedra formation. The increase in ionic conductivity with SiO2 addition was explained with the help of ‘mixed glass former effect’. The increase in density and Tg of LB glasses with SiO2 addition after gamma irradiation has been attributed to fragmentation of bigger ring structure into smaller rings, which increases the density of cross linking and hence compaction. The exposure of gamma irradiation has lead to decrease in ionic conductivity of LB glasses with SiO2 addition. The atomic displacement caused by gamma irradiation resulted in filling of interstices and decrease in trapping sites. This explains the obtained decrease in ionic conductivity after gamma irradiation of glasses. The obtained results of effect of SiO2 addition and gamma irradiation on the density, Tg and ionic conductivity has been supported by FTIR results.

  9. SIMULTANEOUS OBSERVATIONS OF SiO AND H2O MASERS TOWARD SYMBIOTIC STARS

    International Nuclear Information System (INIS)

    Cho, Se-Hyung; Kim, Jaeheon

    2010-01-01

    We present the results of simultaneous observations of SiO v = 1, 2, J = 1-0, 29 SiO v = 0, J = 1-0, and H 2 O 6 16 -5 23 maser lines performed with the KVN Yonsei 21 m radio telescope from 2009 November to 2010 January. We searched for these masers in 47 symbiotic stars and detected maser emission from 21 stars, giving the first time detection from 19 stars. Both SiO and H 2 O masers were detected from seven stars of which six were D-type symbiotic stars and one was an S-type star, WRAY 15-1470. In the SiO maser emission, the 28 SiO v = 1 maser was detected from 10 stars, while the v = 2 maser was detected from 15 stars. In particular, the 28 SiO v = 2 maser emission without the v = 1 maser detection was detected from nine stars with a detection rate of 60%, which is much higher than that of isolated Miras/red giants. The 29 SiO v = 0 maser emission was also detected from two stars, H 2-38 and BF Cyg, together with the 28 SiO v = 2 maser. We conclude that these different observational results between isolated Miras/red giants and symbiotic stars may be related with the presence of hot companions in a symbiotic binary system.

  10. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, Jonas

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment,

  11. Tunable graphene doping by modulating the nanopore geometry on a SiO2/Si substrate

    KAUST Repository

    Lim, Namsoo; Yoo, Tae Jin; Kim, Jin Tae; Pak, Yusin; Kumaresan, Yogeenth; Kim, Hyeonghun; Kim, Woochul; Lee, Byoung Hun; Jung, Gun Young

    2018-01-01

    A tunable graphene doping method utilizing a SiO2/Si substrate with nanopores (NP) was introduced. Laser interference lithography (LIL) using a He–Cd laser (λ = 325 nm) was used to prepare pore size- and pitch-controllable NP SiO2/Si substrates

  12. Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

    Science.gov (United States)

    Shearer, Jeffrey C.

    Functionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as --OH and --NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxC y and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2 O3 supported nanoparticles. Specifically, film composition was

  13. Creating a Social World

    Science.gov (United States)

    Kendler, Kenneth S.; Jacobson, Kristen C.; Gardner, Charles O.; Gillespie, Nathan; Aggen, Steven A.; Prescott, Carol A.

    2014-01-01

    Context Peer-group deviance is strongly associated with externalizing behaviors. We have limited knowledge of the sources of individual differences in peer-group deviance. Objective To clarify genetic and environmental contributions to peer-group deviance in twins from mid-childhood through early adulthood. Design Retrospective assessments using a life-history calendar. Analysis by biometric growth curves. Setting General community. Participants Members of male-male pairs from the population-based Virginia Twin Registry personally interviewed in 1998–2004 (n=1802). Main Outcome Measure Self-reported peer-group deviance at ages 8 to 11, 12 to 14, 15 to 17, 18 to 21, and 22 to 25 years. Results Mean and variance of peer-group deviance increased substantially with age. Genetic effects on peer-group deviance showed a strong and steady increase over time. Family environment generally declined in importance over time. Individual-specific environmental influences on peer-group deviance levels were stable in the first 3 age periods and then increased as most twins left home. When standardized, the heritability of peer-group deviance is approximately 30% at ages 8 to 11 years and rises to approximately 50% across the last 3 time periods. Both genes and shared environment contributed to individual differences in the developmental trajectory of peer-group deviance. However, while the correlation between childhood peer-group deviance levels and the subsequent slope of peer-group deviance over time resulting from genetic factors was positive, the same relationship resulting from shared environmental factors was negative. Conclusions As male twins mature and create their own social worlds, genetic factors play an increasingly important role in their choice of peers, while shared environment becomes less influential. The individual specific environment increases in importance when individuals leave home. Individuals who have deviant peers in childhood, as a result of genetic vs

  14. Magnetically aligned dust and SiO maser polarisation in the envelope of the red supergiant VY Canis Majoris

    Science.gov (United States)

    Vlemmings, W. H. T.; Khouri, T.; Martí-Vidal, I.; Tafoya, D.; Baudry, A.; Etoka, S.; Humphreys, E. M. L.; Jones, T. J.; Kemball, A.; O'Gorman, E.; Pérez-Sánchez, A. F.; Richards, A. M. S.

    2017-07-01

    Aims: Polarisation observations of circumstellar dust and molecular (thermal and maser) lines provide unique information about dust properties and magnetic fields in circumstellar envelopes of evolved stars. Methods: We use Atacama Large Millimeter/submillimeter Array (ALMA) Band 5 science verification observations of the red supergiant VY CMa to study the polarisation of SiO thermal/maser lines and dust continuum at 1.7 mm wavelength. We analyse both linear and circular polarisation and derive the magnetic field strength and structure, assuming the polarisation of the lines originates from the Zeeman effect, and that of the dust originates from aligned dust grains. We also discuss other effects that could give rise to the observed polarisation. Results: We detect, for the first time, significant polarisation ( 3%) of the circumstellar dust emission at millimeter wavelengths. The polarisation is uniform with an electric vector position angle of 8°. Varying levels of linear polarisation are detected for the J = 4 - 328SiO v = 0, 1, 2, and 29SiO v = 0, 1 lines, with the strongest polarisation fraction of 30% found for the 29SiO v = 1 maser. The linear polarisation vectors rotate with velocity, consistent with earlier observations. We also find significant (up to 1%) circular polarisation in several lines, consistent with previous measurements. We conclude that the detection is robust against calibration and regular instrumental errors, although we cannot yet fully rule out non-standard instrumental effects. Conclusions: Emission from magnetically aligned grains is the most likely origin of the observed continuum polarisation. This implies that the dust is embedded in a magnetic field >13 mG. The maser line polarisation traces the magnetic field structure. The magnetic field in the gas and dust is consistent with an approximately toroidal field configuration, but only higher angular resolution observations will be able to reveal more detailed field structure. If the

  15. Gas migration from oil and gas fields and associated hazards

    International Nuclear Information System (INIS)

    Gurevich, A.E.; Endres, B.L.; Robertson Jr, J.O.; Chilingar, G.V.

    1993-01-01

    The migration of gas from oil and gas formations to the surface is a problem that greatly affects those surface areas where human activity exists. Underground gas storage facilities and oil fields have demonstrated a long history of gas migration problems. Experience has shown that the migration of gas to the surface creates a serious potential risk of explosion, fires, noxious odors and potential emissions of carcinogenic chemicals. These risks must be seriously examined for all oil and gas operations located in urban areas. This paper presents the mechanics of gas migration, paths of migration and a review of a few of the risks that should be considered when operating a gas facility in an urban area. The gas can migrate in a continuous or discontinuous stream through porous, water-filled media to the surface. The primary force in this migration of gas is the difference between specific weights of gas and water

  16. Precipitation of amorphous SiO2 particles and their properties

    Directory of Open Access Journals (Sweden)

    S. Musić

    2011-03-01

    Full Text Available The experimental conditions were optimized for the synthesis of amorphous SiO2 particles by the reaction of neutralization of sodium silicate solution with H2SO4 solution. Amorphous SiO2 particles were characterized by XRD, FT-IR, FE-SEM, EDS and microelectrophoresis. The amorphous peak was located at 2θ = 21.8º in the XRD pattern. Primary SiO2 particles were ~ 15 to ~ 30 nm in size and they aggregated into bigger particles. Amorphous SiO2 particles showed a specific surface area up to 130 m²g-1, dependent on the parameters of the precipitation process. The EDS spectrum of amorphous SiO2 particles did not show contamination with sulfate or other ions, which cannot be excluded in traces. pHzpc =1.7 was obtained by microelectrophoresis.

  17. PECVD SiO2 dielectric for niobium Josephson IC process

    International Nuclear Information System (INIS)

    Lee, S.Y.; Nandakumar, V.; Murdock, B.; Hebert, D.

    1991-01-01

    PECVD SiO 2 dielectric has been evaluated as an insulator for a Nb-based, all-refractory Josephson integrated circuit process. First, the properties of PECVD SiO 2 films were measured and compared with those of evaporated SiO films. Second, the PECVD SiO 2 dielectric film was used in our Nb-based Josephson integrated circuit process. The main problem was found to be the deterioration of the critical temperature of the superconducting niobium adjacent to the SiO 2 . The cause and a solution of the problem were investigated. Finally, a Josephson integrated sampler circuit was fabricated and tested. This paper shows acceptable junction I-V characteristics and a measured time resolution of a 4.9 ps pulse in liquid helium

  18. Observation of microstructure of hydrated Ca3SiO5

    International Nuclear Information System (INIS)

    Mori, Kazuhiro; Sato, Takashi; Fukunaga, Toshiharu; Oishi, Koji; Kimura, Katsuhiko; Iwase, Kenji; Sugiyama, Masaaki; Itoh, Keiji; Shikanai, Fumihito; Wuernisha, Tuerxun; Yonemura, Masao; Sulistyanintyas, Dyah; Tsukushi, Itaru; Takata, Shinich; Otomo, Toshiya; Kamiyma, Takashi; Kawai, Masayoshi

    2006-01-01

    Quasi-elastic neutron scattering experiments were carried out to evaluate the hydration rate of tricalcium silicate (Ca 3 SiO 5 ). Furthermore, in the early hydration period, a variation in surface roughness of Ca 3 SiO 5 was observed in nano-scale by the small-angle neutron scattering. From these results, it was found that the hydration rate of Ca 3 SiO 5 is suppressed when the surface of Ca 3 SiO 5 becomes rough through the creation of hydration products C-S-H gel and Ca(OH) 2 , and this roughness is associated with changes in the Ca 3 SiO 5 hydration rate

  19. Creating a family health history

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000947.htm Creating a family health history To use the sharing ... Many health problems tend to run in families. Creating a family history can help you and your ...

  20. Synthesis and characterization of ion-implanted Pt nanocrystals in SiO2

    International Nuclear Information System (INIS)

    Giulian, R.; Kluth, P.; Johannessen, B.; Araujo, L.L.; Llewellyn, D.J.; Cookson, D.J.; Ridgway, M.C.

    2007-01-01

    Pt nanocrystals (NCs) produced by ion implantation in SiO 2 films were investigated by Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The implantations were performed at liquid nitrogen temperature using energies between 3.4 and 5.6 MeV and an ion fluence range of 2-30 x 10 16 cm -2 and were followed by annealing in forming gas (95% N 2 , 5% H 2 ) for one hour at temperatures between 500 and 1100 deg. C. TEM analysis revealed that the NCs are spherical in shape. The mean size of the NCs annealed at 1100 deg. C varied between 2.8 and 3.6 nm for the highest and lowest fluences, respectively, as determined with both TEM and SAXS. In contrast to previous studies on ion implanted metal NCs, larger Pt NCs are located far beyond the Pt peak concentration, potentially the result of a strongly defect mediated NC nucleation

  1. Silicon (100)/SiO2 by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-25

    Silicon (100) wafers are ubiquitous in microfabrication and, accordingly, their surface characteristics are important. Herein, we report the analysis of Si (100) via X-ray photoelectron spectroscopy (XPS) using monochromatic Al K radiation. Survey scans show that the material is primarily silicon and oxygen, and the Si 2p region shows two peaks that correspond to elemental silicon and silicon dioxide. Using these peaks the thickness of the native oxide (SiO2) was estimated using the equation of Strohmeier.1 The oxygen peak is symmetric. The material shows small amounts of carbon, fluorine, and nitrogen contamination. These silicon wafers are used as the base material for subsequent growth of templated carbon nanotubes.

  2. Nucleation of C60 on ultrathin SiO2

    Science.gov (United States)

    Conrad, Brad; Groce, Michelle; Cullen, William; Pimpinelli, Alberto; Williams, Ellen; Einstein, Ted

    2012-02-01

    We utilize scanning tunneling microscopy to characterize the nucleation, growth, and morphology of C60 on ultrathin SiO2 grown at room temperature. C60 thin films are deposited in situ by physical vapor deposition with thicknesses varying from <0.05 to ˜1 ML. Island size and capture zone distributions are examined for a varied flux rate and substrate deposition temperature. The C60 critical nucleus size is observed to change between monomers and dimers non-monotonically from 300 K to 500 K. Results will be discussed in terms of recent capture zone studies and analysis methods. Relation to device fabrication will be discussed. doi:10.1016/j.susc.2011.08.020

  3. Annealing temperature and environment effects on ZnO nanocrystals embedded in SiO2: a photoluminescence and TEM study.

    Science.gov (United States)

    Pita, Kantisara; Baudin, Pierre; Vu, Quang Vinh; Aad, Roy; Couteau, Christophe; Lérondel, Gilles

    2013-12-06

    We report on efficient ZnO nanocrystal (ZnO-NC) emission in the near-UV region. We show that luminescence from ZnO nanocrystals embedded in a SiO2 matrix can vary significantly as a function of the annealing temperature from 450°C to 700°C. We manage to correlate the emission of the ZnO nanocrystals embedded in SiO2 thin films with transmission electron microscopy images in order to optimize the fabrication process. Emission can be explained using two main contributions, near-band-edge emission (UV range) and defect-related emissions (visible). Both contributions over 500°C are found to be size dependent in intensity due to a decrease of the absorption cross section. For the smallest-size nanocrystals, UV emission can only be accounted for using a blueshifted UV contribution as compared to the ZnO band gap. In order to further optimize the emission properties, we have studied different annealing atmospheres under oxygen and under argon gas. We conclude that a softer annealing temperature at 450°C but with longer annealing time under oxygen is the most preferable scenario in order to improve near-UV emission of the ZnO nanocrystals embedded in an SiO2 matrix.

  4. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project - Systems Integration and Operationalization (SIO) Demonstration

    Science.gov (United States)

    Swieringa, Kurt

    2018-01-01

    The UAS-NAS Project hosted a Systems Integration Operationalization (SIO) Industry Day for the SIO Request for Information (RFI) on November 30, 2017 in San Diego, California. This presentation is being presented to the same group as a follow up regarding the progress that the UAS-NAS project has made on the SIO RFI. The presentation will be virtual with a teleconference

  5. The electrorheological properties of nano-sized SiO2 particle materials doped with rare earths

    International Nuclear Information System (INIS)

    Liu Yang; Liao Fuhui; Li Junran; Zhang Shaohua; Chen Shumei; Wei Chenguan; Gao Song

    2006-01-01

    Electrorheological (ER) materials of pure SiO 2 and SiO 2 doped with rare earths (RE = Ce, Gd, Y) (non-metallic glasses (silicates)) were prepared using Na 2 SiO 3 and RECl 3 as starting materials. The electrorheological properties are not enhanced by all rare earth additions. The material doped with Ce exhibits the best ER performance

  6. Multifunctional hollow superhydrophobic SiO2 microspheres with robust and self-cleaning and separation of oil/water emulsions properties.

    Science.gov (United States)

    Guo, Fei; Wen, Qiuying; Peng, Yubing; Guo, Zhiguang

    2017-05-15

    Superhydrophobic materials have drawn great attention due to its' remarkable non-wetting properties and applications in many fields. In this paper, we synthesize a hollow superhydrophobic SiO 2 powder by typical template method and self-assembly functionalization. Robustness of many superhydrophobic surfaces has become the development bottleneck for industrial applications. Aiming at this problem, the adhesive epoxy resin is specially taken to use as the binding layer between superhydrophobic SiO 2 powder and substrates to create robust superhydrophobic coating. The mechanical durability of the obtained superhydrophobic coating is evaluated by a cyclic sandpaper abrasion. Also, the chemical stability of this superhydrophobic coating is assessed by exposuring it to different pH conditions and UV irradiation, respectively. Significantly, because of the special structure and superhydrophobicity/superoleophilicity of the hollow microspheres, these hollow superhydrophobic SiO 2 powders manifest great oil-adsorbing capacity, which thus can be used to separate oil/water mixtures and remove oil from oil-in-water emulsions. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Enhanced antioxidation and microwave absorbing properties of SiO2-coated flaky carbonyl iron particles

    Science.gov (United States)

    Zhou, Yingying; Xie, Hui; Zhou, Wancheng; Ren, Zhaowen

    2018-01-01

    SiO2 was successfully coated on the surface of flaky carbonyl iron particles using a chemical bath deposition method in the presence of 3-aminopropyl triethoxysilane (APTES). The morphologies, composition, valence states of elements, as well as antioxidation and electromagnetic properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and microwave network analyzer. TG curve shows the obvious weight gain of carbonyl iron was deferred to 360 °C after SiO2-coated, which can be ascribed to the exits of SiO2 overlayer. Compared with the raw carbonyl iron, SiO2-coated sample shows good wave absorption performance due to its impedance matching. The electromagnetic properties of raw and SiO2-coated carbonyl iron particles were characterized in X band before and after heat treatment at 250 °C for 10 h. It was established that SiO2-coated carbonyl iron demonstrate good thermal stability, indicating SiO2-coating is useful in the usage of microwave absorbers operating at temperature up to 250 °C.

  8. Preparation and Characterization of SiO2/SiCN Core-shell Ceramic Microspheres

    Directory of Open Access Journals (Sweden)

    ZHANG Hai-yuan

    2017-05-01

    Full Text Available The SiO2/PSN core-shell microspheres were prepared via an emulsion reaction combined with the polymer-derived ceramics (PDCs method using polysilazane (PSN in situ polymerization on the surface of SiO2 modified by silane coupling agents MPS, followed by pyrolysis process to obtain SiO2/SiCN core-shell ceramic microspheres. The effects of raw mass ratio, curing time and pyrolysis temperature on the formation and the morphology of core-shell microspheres were studied. The morphology, chemical composition and phase transformation were characterized by SEM, EDS, TEM, FT-IR and XRD. The results show that after reaction for 4h at 200℃, SiO2 completely coated PSN forms a core-shell microsphere with rough surface when the mass ratio of SiO2 and PSN is 1:4; when pyrolysis temperature is at 800-1200℃, amorphous SiO2/SiCN core-shell ceramic microspheres are prepared; at 1400℃, the amorphous phase partially crystallizes to produce SiO2, SiC and Si3N4 phase.

  9. On the Relation of Silicates and SiO Maser in Evolved Stars

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiaming; Jiang, Biwei, E-mail: bjiang@bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)

    2017-04-01

    The SiO molecule is one of the candidates for the seed of silicate dust in the circumstellar envelope of evolved stars, but this opinion is challenged. In this work we investigate the relation of the SiO maser emission power and the silicate dust emission power. With both our own observation by using the PMO/Delingha 13.7 m telescope and archive data, a sample is assembled of 21 SiO v  = 1, J  = 2 − 1 sources and 28 SiO v  = 1, J  = 1 − 0 sources that exhibit silicate emission features in the ISO /SWS spectrum as well. The analysis of their SiO maser and silicate emission power indicates a clear correlation, which is not against the hypothesis that the SiO molecules are the seed nuclei of silicate dust. On the other hand, no correlation is found between SiO maser and silicate crystallinity, which may imply that silicate crystallinity does not correlate with mass-loss rate.

  10. Depth-resolved detection and process dependence of traps at ultrathin plasma-oxidized and deposited SiO2/Si interfaces

    International Nuclear Information System (INIS)

    Brillson, L. J.; Young, A. P.; White, B. D.; Schaefer, J.; Niimi, H.; Lee, Y. M.; Lucovsky, G.

    2000-01-01

    Low-energy electron-excited nanoluminescence spectroscopy reveals depth-resolved optical emission associated with traps near the interface between ultrathin SiO 2 deposited by plasma-enhanced chemical vapor deposition on plasma-oxidized crystalline Si. These near-interface states exhibit a strong dependence on local chemical bonding changes introduced by thermal/gas processing, layer-specific nitridation, or depth-dependent radiation exposure. The depth-dependent results provide a means to test chemical and structural bond models used to develop advanced dielectric-semiconductor junctions. (c) 2000 American Vacuum Society

  11. Dissolution rate enhancement of the poorly water-soluble drug Tibolone using PVP, SiO2, and their nanocomposites as appropriate drug carriers.

    Science.gov (United States)

    Papadimitriou, Sofia; Bikiaris, Dimitrios

    2009-09-01

    Creation of immediate release formulations for the poorly water-soluble drug Tibolone through the use of solid dispersions (SDs). SD systems of Tibolone (Tibo) with poly(vinylpyrrolidone) (PVP), fumed SiO(2) nanoparticles, and their corresponding ternary systems (PVP/SiO(2)/Tibo) were prepared and studied in order to produce formulations with enhanced drug dissolution rates. The prepared SDs were characterized by the use of differential scanning calorimetry and wide-angle X-ray diffractometry techniques. Also dissolution experiments were performed. From the results it was concluded that PVP as well as SiO(2) can be used as appropriate carriers for the amorphization of Tibo, even when the drug is used at high concentrations (20-30%, w/w). This is due to the evolved interactions taking place between the drug and the used carriers, as was verified by Fourier transform infrared spectroscopy. At higher concentrations the drug was recrystallized. Similar are the observations on the ternary PVP/SiO(2)/Tibo SDs. The dissolution profiles of the drug in PVP/Tibo and SiO(2)/Tibo SDs are directly dependent on the physical state of the drug. Immediately release rates are observed in SD with low drug concentrations, in which Tibo was in amorphous state. However, these release profiles are drastically changed in the ternary PVP/SiO(2)/Tibo SDs. An immediate release profile is observed for low drug concentrations and an almost sustained release as the concentration of Tibo increases. This is due to the weak interactions that take place between PVP and SiO(2), which result in alterations of the characteristics of the carrier (PVP/SiO(2) nanocomposites). Immediate release formulation was created for Tibolone as well as new nanocomposite matrices of PVP/SiO((2)), which drastically change the release profile of the drug to a sustained delivery.

  12. Stability analysis of SiO2/SiC multilayer coatings

    International Nuclear Information System (INIS)

    Fu Zhiqiang; Jean-Charles, R.

    2006-01-01

    The stability behaviours of SiC coatings and SiO 2 /SiC coatings in helium with little impurities are studied by HSC Chemistry 4.1, the software for analysis of Chemical reaction and equilibrium in multi-component complex system. It is found that in helium with a low partial pressure of oxidative impurities under different total pressure, the key influence factor controlling T cp of SiC depends is the partial pressure of oxidative impurities; T cp of SiC increases with the partial pressure of oxidative impurities. In helium with a low partial pressure of different impurities, the key influence factor of T cs of SiO 2 are both the partial pressure of impurities and the amount of impurities for l mol SiO 2 ; T cs of SiO 2 increases with the partial pressure of oxidative impurities at the same amount of the impurities for 1 mol SiO 2 while it decreases with the amount of the impurities for 1 mm SiO 2 at the same partial pressure of the impurities. The influence of other impurities on T cp of SiC in He-O 2 is studied and it is found that CO 2 , H 2 O and N-2 increase T cp of SiC in He-O 2 while H 2 , CO and CH 4 decrease T cp of SiC He-O 2 . When there exist both oxidative impurities and reductive impurities, their effect on T cs of SiO 2 can be suppressed by the other. In HTR-10 operation atmosphere, SiO 2 /SiC coatings can keep stable status at higher temperature than SiC coatings, so SiO 2 /SiC coatings is more suitable to improve the oxidation resistance of graphite in HTR-10 operation atmosphere compared with SiC coatings. (authors)

  13. Structural Stability and Performance of Noble Metal-Free SnO2-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Antonio Tricoli

    2012-05-01

    Full Text Available The structural stability of pure SnO2 nanoparticles and highly sensitive SnO2-SiO2 nanocomposites (0–15 SiO2 wt% has been investigated for conditions relevant to their utilization as chemoresistive gas sensors. Thermal stabilization by SiO2 co-synthesis has been investigated at up to 600 °C determining regimes of crystal size stability as a function of SiO2-content. For operation up to 400 °C, thermally stable crystal sizes of ca. 24 and 11 nm were identified for SnO2 nanoparticles and 1.4 wt% SnO2-SiO2 nanocomposites, respectively. The effect of crystal growth during operation (TO = 320 °C on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms. In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration. Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

  14. Fabrication and properties of highly luminescent materials from Tb(OH)3-SiO2 and Tb(OH)3-SiO2:Eu3+ nanotubes

    International Nuclear Information System (INIS)

    Tran Thu Huong; Tran Kim Anh; Le Quoc Minh

    2009-01-01

    Luminescent nanomaterials with one-dimensional (1D) structures have attracted much attention due to their unique properties and potential applications in nanophotonics and nanobiophotonics. In this paper, we report a synthesis of terbium - hydroxide - at - silica Tb(OH) 3 -SiO 2 and Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes. Terbium - hydroxide tubes were synthesized by soft template method. The size of the tubes can be controlled precisely and have outer diameters ranging from 80 to 120 nm, wall thickness of about 30 nm, and lengths ranging from 300 to 800 nm. To fabricate core/shell materials, the seed growth method is used. FESEM, X-ray diffraction, Raman spectra of Tb(OH) 3 and Tb(OH) 3 -SiO 2 nanotubes were investigated. The photoluminescence (PL) spectrum of Tb(OH) 3 under 325 nm excitation consists of four main peaks at 488, 542, 582, and 618 nm. Furthermore, a preliminary suggestion for the mechanism of growth of the Tb(OH) 3 nanotubes using the soft - template synthesis technique has been proposed. The PL intensity from Tb(OH) 3 -SiO 2 or Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes is much stronger than that of Tb(OH) 3 .

  15. Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO2

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Jinschek, Joerg R.; Ou, Haiyan

    2012-01-01

    electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters. (C) 2012 American......A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO2 doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using...

  16. Self-Ordered Voids Formation in SiO2 Matrix by Ge Outdiffusion

    OpenAIRE

    B. Pivac; P. Dubček; J. Dasović; H. Zorc; S. Bernstorff; J. Zavašnik; B. Vlahovic

    2018-01-01

    The annealing behavior of very thin SiO2/Ge multilayers deposited on Si substrate by e-gun deposition in high vacuum was explored. It is shown that, after annealing at moderate temperatures (800°C) in inert atmosphere, Ge is completely outdiffused from the SiO2 matrix leaving small (about 3 nm) spherical voids embedded in the SiO2 matrix. These voids are very well correlated and formed at distances governed by the preexisting multilayer structure (in vertical direction) and self-organization ...

  17. Cytotoxicity and effect on GJIC of SiO2 nanoparticles in HL-7702 cells

    International Nuclear Information System (INIS)

    Pan Tao; Jin Minghua; Liu Xiaomei; Du Zhongjun; Zhou Xianqing; Huang Peili; Sun Zhiwei

    2013-01-01

    Objective: To study the cytotoxicity and effect on gap junction intracellular communication (GJIC) of SiO 2 nanoparticles in HL-7702 cells, and to provide experimental basis for toxicity assessment and the security applications of SiO 2 nanoparticles. Methods: Transmission electron microscope (TEM) was used to characterize two kinds of SiO 2 nanoparticles, verifying their size, dispersion and shape; dynamic light scattering (DLS) method was used to analyze the water dispersion and culture medium dispersion of the SiO 2 nanoparticles; MTT assay was carried out to examine the cytotoxicities of the two sizes SiO 2 nanoparticles on the cells; lactate dehydrogenase (LDH) release assay was performed to examine the integrity nano of the cell membrane; Scrape-loading and dye transfer assay was performed to examine the effect of SiO 2 nanoparticles on GJIC. Results: Based on the result of TEM, two kinds of SiO 2 nanoparticles were spherically shaped, uniformly sized and sporadically dispersed; the statistical analysis results showed the diameters of the two nanoparticles were (447.60±20.78) nm and (67.42±5.69) nm, respectively, thus they could be categorized as submicron scale and nano scale. The DLS method results manifested that the hydration nanoparticle sizes of the two SiO 2 nanoparticles were (684.37±18.76) nm, (128.31±7.64) nm in high purity water and (697.02±19.57) nm, (133.74±8.97) nm in RPMI-1640 solution, all the two nanoparticles were well dispersed without aggregation. MTT assay indicated that 24 h after treatment of SiO 2 nanoparticles, the cell viabilities were affected by both the size and the dose of the SiO 2 nanoparticles; the higher the dose was, the less viability the cells exhibited. Moreover, the nano scale particles inflicted more damage to the cells. LDH release assay indicated that the SiO 2 particles could also damage the cell membrane in a dose-dependent and size-dependent way. Scrape-loading and dye transfer assay indicated that the nano

  18. Si nanocrystals embedded in SiO2: Optical studies in the vacuum ultraviolet range

    DEFF Research Database (Denmark)

    Pankratov, V.; Osinniy, Viktor; Kotlov, A.

    2011-01-01

    done. It is demonstrated that the experimentally determined blueshift of the photoluminescence excitation and absorption spectra is larger than the theoretical predictions. The influence of point defects in the SiO2 matrix on the optical and luminescence properties of the embedded Si nanocrystals...... is discussed. Moreover, it is demonstrated that no energy transfer takes place between the SiO2 and Si nanocrystals when the excitation energy is higher than the band-to-band transition energy in SiO2....

  19. Gas turbine

    International Nuclear Information System (INIS)

    Yang, Ok Ryong

    2004-01-01

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  20. A facile approach to fabricate Au nanoparticles loaded SiO2 microspheres for catalytic reduction of 4-nitrophenol

    International Nuclear Information System (INIS)

    Tang, Mingyi; Huang, Guanbo; Li, Xianxian; Pang, Xiaobo; Qiu, Haixia

    2015-01-01

    Hydrophilic and biocompatible macromolecules were used to improve and simplify the process for the fabrication of core/shell SiO 2 @Au composite particles. The influence of polymers on the morphology of SiO 2 @Au particles with different size of SiO 2 cores was analyzed by transmission electron microscopy and scanning electron microscopy. The optical property of the SiO 2 @Au particles was studied with UV–Vis spectroscopy. The results indicate that the structure and composition of macromolecules affect the morphology of Au layers on SiO 2 microspheres. The SiO 2 @Au particles prepared in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) have thin and complete Au nanoshells owing to their inducing act in preferential growth of Au nanoparticles along the surface of SiO 2 microspheres. SiO 2 @Au particles can be also prepared from SiO 2 microspheres modified with 3-aminopropyltrimethoxysilane in the presence of PVA or PVP. This offers a simple way to fabricate a Au layer on SiO 2 or other microspheres. The SiO 2 @Au particles demonstrated high catalytic activity in the reduction of 4-nitrophenol. - Highlights: • Facile direct deposition method for Au nanoparticles on silica microspheres. • Influence of different types of macromolecule on the formation of Au shell. • High catalytic performance of Au nanoparticles on silica microspheres

  1. Synthesis and characterization of Yb and Er based monosilicate powders and durability of plasma sprayed Yb2SiO5 coatings on C/C–SiC composites

    International Nuclear Information System (INIS)

    Khan, Zuhair S.; Zou Binglin; Huang Wenzhi; Fan Xizhi; Gu Lijian; Chen Xiaolong; Zeng Shuibing; Wang Chunjie; Cao Xueqiang

    2012-01-01

    Highlights: ► Ultra-pure rare-earth monosilicate powders based on Er and Yb have been fabricated by solid-state reaction. ► Spray-drying treatment results in powders with free flowing characteristics and rounded surface morphologies. ► CTEs are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 . ► Plasma spraying has been used to deposit Yb 2 SiO 5 coatings on C/C–SiC substrate. ► Coatings remain strongly intact with the substrate on thermal cycling between ∼400 °C and 1500 °C in gas burner rig experiment. - Abstract: Rare-earth silicates such as Yb 2 SiO 5 and Er 2 SiO 5 are promising environmental barrier coating materials for ceramic matrix composites. In this work, Yb 2 SiO 5 and Er 2 SiO 5 ceramic powders have been synthesized by solid-state reaction using Yb 2 O 3 , Er 2 O 3 and SiO 2 as starting materials. The fabricated powders were subjected to spray drying treatment for subsequent synthesis of coatings by plasma spraying. The spray drying resulted in well-dispersed and spherical powder particles with good flowability. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and differential scanning calorimetry (TGA/DSC) and dilatometry were applied to study the microstructural and thermal characteristics of the powders. Ultra-high purity monosilicate powders formed as a result of heating treatments at 1400 °C in a box furnace for 20 h. TG/DSC revealed the genesis temperatures of the silicate formation (low temperature polymorphs) and also showed that the solid-state reactions to form Yb and Er based monosilicates proceeded without any weight-loss in the tested temperature range. The values of coefficients of thermal expansion (CTE) of the fabricated compounds are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 by dilatometric measurements. Besides these studies, coating formation by plasma spraying of spray-dried Yb 2 SiO 5 powders on the ceramic

  2. Creating

    DEFF Research Database (Denmark)

    Andersen, Kristina Vaarst; Lorenzen, Mark; Laursen, Stine

    2012-01-01

    This unique book reveals the procedural aspects of knowledge-based urban planning, development and assessment. Concentrating on major knowledge city building processes, and providing state-of-the-art experiences and perspectives, this important compendium explores innovative models, approaches an...

  3. Surface morphology of amorphous germanium thin films following thermal outgassing of SiO2/Si substrates

    International Nuclear Information System (INIS)

    Valladares, L. de los Santos; Dominguez, A. Bustamante; Llandro, J.; Holmes, S.; Quispe, O. Avalos; Langford, R.; Aguiar, J. Albino; Barnes, C.H.W.

    2014-01-01

    Highlights: • Annealing promotes outgassing of SiO 2 /Si wafers. • Outgassing species embed in the a-Ge film forming bubbles. • The density of bubbles obtained by slow annealing is smaller than by rapid annealing. • The bubbles explode after annealing the samples at 800 °C. • Surface migration at higher temperatures forms polycrystalline GeO 2 islands. - Abstract: In this work we report the surface morphology of amorphous germanium (a-Ge) thin films (140 nm thickness) following thermal outgassing of SiO 2 /Si substrates. The thermal outgassing was performed by annealing the samples in air at different temperatures from 400 to 900 °C. Annealing at 400 °C in slow (2 °C/min) and fast (10 °C/min) modes promotes the formation of bubbles on the surface. A cross sectional view by transmission electron microscope taken of the sample slow annealed at 400 °C reveals traces of gas species embedded in the a-Ge film, allowing us to propose a possible mechanism for the formation of the bubbles. The calculated internal pressure and number of gas molecules for this sample are 30 MPa and 38 × 10 8 , respectively. Over an area of 22 × 10 −3 cm 2 the density of bubbles obtained at slow annealing (9 × 10 3 cm −2 ) is smaller than that at rapid annealing (6.4 × 10 4 cm −2 ), indicating that the amount of liberated gas in both cases is only a fraction of the total gas contained in the substrate. After increasing the annealing temperature in the slow mode, bubbles of different diameters (from tens of nanometers up to tens of micrometers) randomly distribute over the Ge film and they grow with temperature. Vertical diffusion of the outgas species through the film dominates the annealing temperature interval 400–600 °C, whereas coalescence of bubbles caused by lateral diffusion is detected after annealing at 700 °C. The bubbles explode after annealing the samples at 800 °C. Annealing at higher temperatures, such as 900 °C, leads to surface migration of the

  4. Phonon spectra in SiO2 glasses

    International Nuclear Information System (INIS)

    Perez R, J.F.; Jimenez S, S.; Gonzalez H, J.; Vorobiev, Y.V.; Hernandez L, M.A.; Parga T, J.R.

    1999-01-01

    Phonon spectra in SiO 2 sol-gel made glasses annealed under different conditions are investigated using infrared absorption and Raman scattering. These data are compared with those obtained in commercial optical-quality quartz. All the materials exhibit the same phonon bands, the exact position and the intensity depend on the measuring technique and on the sample preparation method. The phonon spectra in this material are interpreted on the basis of a simple quasi-linear description of elastic waves in an O-Si-O chain. It is shown that the main features observed in the range 400-1400 cm -1 can be predicted using a quasi-linear chain model in which the band at 1070 cm -1 is assigned to the longitudinal optical waves in the O-Si-O chain with the smallest possible wavelength at the Brillouin zone boundary, the band located around 450 cm -1 is assigned to the transversal optical waves and the band at 800 cm -1 to the longitudinal acoustical waves with the same wavelength. The degree of structural disorder can be also deduced within the framework of the proposed model. (Author)

  5. Functionalized sio2 microspheres for extracting oil from produced water

    KAUST Repository

    Mishra, Himanshu

    2017-03-16

    Functionalized material, methods of producing the functionalized material, and use thereof for separation processes such as but not limited to use for separating and extracting a dissolved organic foulant, charged contaminant or oily matter or any combination thereof from water, such as produced water, are provided. In an embodiment, the functionalized material is a mineral material, such as mica, silica (e.g. an SiO2 microsphere) or a metal oxide, and the outer surface of the material is functionalized with an alkyl chain or a perfluorinated species. In an embodiment, the method of making the functionalized material, includes: a) providing a mineral material; b) providing an alkyl chain and/or a perfluorinated species, the alkyl chain or perfluorinated species selected to dissolve organic foulants, charged contaminants or oily matter from water or any combination thereof; c) hydroxylating the material via a concentrated acid solution or a basic solution; and d) grafting the alkyl chain and/or the perfluorinated species onto the material via a silanation reaction.

  6. Gas-on-gas competition in Shanghai

    International Nuclear Information System (INIS)

    Manuhutu, Chassty; Owen, Anthony D.

    2010-01-01

    In common with other major economic centres in China, Shanghai's energy consumption has been increasing rapidly to support the high growth rate of its economy. To achieve rational, efficient and clean use of energy, together with improved environmental quality within the city, the Shanghai municipal government has decided to expand the supply and utilization of natural gas. Shanghai plans to increase the share of natural gas in its primary energy mix to 7 per cent by 2010, up from 3 per cent in 2005. This increase in natural gas demand has to be matched with a corresponding increase in supply. To date, the Shanghai region has relied on offshore extracted natural gas but this supply is limited due to the size of the reserves. Since 2005, the West-East pipeline has provided an alternative for Shanghai but demands from other regions could reduce the potential for expanding supplies from that source. Since domestic production will not be sufficient to meet demand in the near future, Shanghai is building a liquefied natural gas (LNG) regasification terminal at the Yangshan deep-water port that would allow an additional supply of more than 3 billion cubic meters per year of natural gas. Malaysia has already committed to supply LNG to the Shanghai terminal at a price that is significantly higher than the wholesale 'city-gate' price for natural gas transported via pipeline, but still lower than the gas price to end-use consumers. The presence of both an LNG terminal and a transmission pipeline that connects Shanghai to domestic gas-producing regions will create gas-on-gas competition. This study assesses the benefits of introducing such competition to one of China's most advanced cities under various scenarios for demand growth. In this paper, the impact of imported LNG on market concentration in Shanghai's gas market will be analysed using the Herfindahl-Hirschmann index (HHI) and the residual supply index (RSI). Our results show that Shanghai remains a supply

  7. Facile synthesis of microporous SiO2/triangular Ag composite nanostructures for photocatalysis

    Science.gov (United States)

    Sirohi, Sidhharth; Singh, Anandpreet; Dagar, Chakit; Saini, Gajender; Pani, Balaram; Nain, Ratyakshi

    2017-11-01

    In this article, we present a novel fabrication of microporous SiO2/triangular Ag nanoparticles for dye (methylene blue) adsorption and plasmon-mediated degradation. Microporous SiO2 nanoparticles with pore size aminopropyl) trimethoxysilane) to introduce amine groups. Amine-functionalized microporous silica was used for adsorption of triangular silver (Ag) nanoparticles. The synthesized microporous SiO2 nanostructures were investigated for adsorption of different dyes including methylene blue, congo red, direct green 26 and curcumin crystalline. Amine-functionalized microporous SiO2/triangular Ag nanostructures were used for plasmon-mediated photocatalysis of methylene blue. The experimental results revealed that the large surface area of microporous silica facilitated adsorption of dye. Triangular Ag nanoparticles, due to their better charge carrier generation and enhanced surface plasmon resonance, further enhanced the photocatalysis performance.

  8. Efficient photocatalytic activity with carbon-doped SiO2 nanoparticles

    KAUST Repository

    Zhang, Dongen; Wu, Jinbo; Zhou, Bingpu; Hong, Yaying; Li, Shunbo; Wen, Weijia

    2013-01-01

    by thermogravimetric analysis, X-ray diffraction, standard and high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The C-doped SiO2 displayed outstanding photocatalytic properties, as evidenced by its catalysis of Rhodamine B

  9. “LAVOURA ARCAICA”, NIETZSCHE E O MITO DE DIONÍSIO

    Directory of Open Access Journals (Sweden)

    Brunilda T. Reichmann

    2017-03-01

    audaciosos, pela embriaguez. O dionisíaco é paradoxalmente eliminado, no final da narrativa, pela ira paterna, sentimento semelhante ao de Agave, ao assassinar seu filho Penteu, no mito de Dionísio.

  10. Fourier transform infrared spectroscopic study of gamma irradiated SiO2 nanoparticles

    Science.gov (United States)

    Huseynov, Elchin; Garibov, Adil; Mehdiyeva, Ravan; Huseynova, Efsane

    2018-03-01

    In the present work, nano SiO2 particles are investigated before and after gamma irradiation (25, 50, 75, 100 and 200 kGy) using Fourier transform infrared (FTIR) spectroscopy method for the wavenumber between 400-4000 cm-1. It is found that as a result of spectroscopic analysis, five new peaks have appeared after gamma radiation. Two of new obtained peaks (which are located at 687 cm-1 and 2357 cm-1 of wavenumber) were formed as a result of gamma radiation interaction with Si-O bonds. Another three new peaks (peaks appropriate to 941, 2052 and 2357 cm-1 values of wavenumber) appear as a result of interaction of water with nano SiO2 particles after gamma irradiation. It has been defined as asymmetrical bending vibration, symmetrical bending vibration, symmetrical stretching vibration and asymmetrical stretching vibration of Si-O bonds appropriate to peaks.

  11. Characterization of the implantation damage in SiO2 with x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Ajioka, T.; Ushio, S.

    1986-01-01

    X-ray photoelectron spectroscopy (XPS) has been applied to characterize the damage introduced into SiO 2 by ion implantation. By measuring the peak width of Si/sub 2p/ from SiO 2 which corresponds to perturbation of the SiO 2 network, good depth profiles of the damage have been obtained for implanted samples and subsequently annealed samples. The results show that the damage distributed more widely than that calculated from energy deposition and that the perturbation of the network is caused not only by radiation damage but also by the existence of impurities in the network. It has been found that the XPS method is effective to understand the atomic structure, and thus, electrical properties of SiO 2

  12. Synthesis of unidirectional structures of SiO2-Ag using Au nanoparticles as nucleation centers

    International Nuclear Information System (INIS)

    Villa S, G.; Mendoza A, D.; Gutierrez W, C.; Perez H, R.

    2008-01-01

    This paper reports a method to synthesize Ag unidirectional structures covered with SiO 2 by sol-gel technique using Au nanoparticles as nucleation centers of the unidirectional structures. In the first phase unidirectional structures of SiO 2 -Ag CI are obtained by sol-gel, using TEOS as a precursor of metallic structures (Ag) and the incorporation of Au nanoparticles as nucleation centers for growth of unidirectional structures. In the second stage, one-way systems are subjected to thermal treatment in H 2 atmosphere for obtain AG 0 particles through mechanisms that diffusion and coalescence of silver to form structures that have a thin cover of SiO 2 . Analysis by scanning electron microscopy, transmission and atomic force microscopy allowed to determine the chemical composition and microstructural properties of unidirectional systems SiO 2 -Ag. (Author)

  13. Experimental determination of nanofluid specific heat with SiO2 nanoparticles in different base fluids

    Science.gov (United States)

    Akilu, S.; Baheta, A. T.; Sharma, K. V.; Said, M. A.

    2017-09-01

    Nanostructured ceramic materials have recently attracted attention as promising heat transfer fluid additives owing to their outstanding heat storage capacities. In this paper, experimental measurements of the specific heats of SiO2-Glycerol, SiO2-Ethylene Glycol, and SiO2-Glycerol/Ethylene Glycol mixture 60:40 ratio (by mass) nanofluids with different volume concentrations of 1.0-4.0% have been carried out using differential scanning calorimeter at temperatures of 25 °C and 50 °C. Experimental results indicate lower specific heat capacities are found with SiO2 nanofluids compared to their respective base fluids. The specific heat was decreasing with the increase of concentration, and this decrement depends on upon the type of the base fluid. It is observed that temperature has a positive impact on the specific heat capacity. Furthermore, the experimental values were compared with the theoretical model predictions, and a satisfactory agreement was established.

  14. Porous asymmetric SiO2-g-PMMA nanoparticles produced by phase inversion

    KAUST Repository

    Munirasu, Selvaraj; Nunes, Suzana Pereira

    2014-01-01

    of functionalized nanoparticles in different solvents and immersion in water. The resulting asymmetrically porous morphology and nanoparticle assembly was characterized by scanning electron and atomic force microscopy. The PMMA functionalized SiO2 hybrid material

  15. Archive of Geosample Data and Information from the Scripps Institution of Oceanography (SIO) Geological Collections

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The University of California San Diego (UCSD) Scripps Institution of Oceanography (SIO) is a partner in the Index to Marine and Lacustrine Geological Samples (IMLGS)...

  16. Asia Gas Study

    International Nuclear Information System (INIS)

    1996-01-01

    The Asia region has experienced a period of dynamic growth, both of economies and energy demand. The next fifteen years are likely to see further rapid economic growth in Asia. To fuel this growth energy consumption will also increase rapidly. Of all forms of energy, natural gas demand is likely to grow the fastest. The gas sector will face rapid and dramatic change, creating challenges for the governments of the region. Infrastructure, both for export and domestic consumption of gas, will need to expand significantly. Regional trade in natural gas could triple by 2010. Trade will continue to be dominated by liquefied natural gas (LNG) but pipeline exports will also grow rapidly. Investment needs will be large, putting pressure on governments to look for alternative funding mechanisms. As Asian gas transmission and distribution networks expand and become more interconnected, consumer choice becomes possible. How to encourage and regulate competition will become a vital policy question. As gas consumption increases both in absolute terms, and in terms of its share of energy consumption within particular sectors of the economy (for example, as a fuel for power generation), governments will need to give higher priority to policies dealing with gas security. This study examines the current and possible future role of natural gas in Asia. In particular, it examines in detail the relevant energy policies of six of the key gas producing and consuming economies in the region: Brunei-Darussalam, Chinese Taipei, Indonesia, the Republic of Korea, Malaysia and Thailand. (author). 17 figs., 14 tabs., 7 appends

  17. ATLASGAL-selected massive clumps in the inner Galaxy. II. Characterisation of different evolutionary stages and their SiO emission

    Science.gov (United States)

    Csengeri, T.; Leurini, S.; Wyrowski, F.; Urquhart, J. S.; Menten, K. M.; Walmsley, M.; Bontemps, S.; Wienen, M.; Beuther, H.; Motte, F.; Nguyen-Luong, Q.; Schilke, P.; Schuller, F.; Zavagno, A.; Sanna, C.

    2016-02-01

    Context. The processes leading to the birth of high-mass stars are poorly understood. The key first step to reveal their formation processes is characterising the clumps and cores from which they form. Aims: We define a representative sample of massive clumps in different evolutionary stages selected from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL), from which we aim to establish a census of molecular tracers of their evolution. As a first step, we study the shock tracer, SiO, mainly associated with shocks from jets probing accretion processes. In low-mass young stellar objects (YSOs), outflow and jet activity decreases with time during the star formation processes. Recently, a similar scenario was suggested for massive clumps based on SiO observations. Here we analyse observations of the SiO (2-1) and (5-4) lines in a statistically significant sample to constrain the change of SiO abundance and the excitation conditions as a function of evolutionary stage of massive star-forming clumps. Methods: We performed an unbiased spectral line survey covering the 3-mm atmospheric window between 84-117 GHz with the IRAM 30 m telescope of a sample of 430 sources of the ATLASGAL survey, covering various evolutionary stages of massive clumps. A smaller sample of 128 clumps has been observed in the SiO (5-4) transition with the APEX telescope to complement the (2-1) line and probe the excitation conditions of the emitting gas. We derived detection rates to assess the star formation activity of the sample, and we estimated the column density and abundance using both an LTE approximation and non-LTE calculations for a smaller subsample, where both transitions have been observed. Results: We characterise the physical properties of the selected sources, which greatly supersedes the largest samples studied so far, and show that they are representative of different evolutionary stages. We report a high detection rate of >75% of the SiO (2-1) line and a >90% detection

  18. Analysis of SiO2 nanoparticles binding proteins in rat blood and brain homogenate

    Directory of Open Access Journals (Sweden)

    Shim KH

    2014-12-01

    Full Text Available Kyu Hwan Shim,1 John Hulme,1 Eun Ho Maeng,2 Meyoung-Kon Kim,3 Seong Soo A An1 1Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Sungnam-si, 2Department of Analysis, KTR, Kimpo, Gyeonggi-do, 3Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, South Korea Abstract: A multitude of nanoparticles, such as titanium oxide (TiO2, zinc oxide, aluminum oxide, gold oxide, silver oxide, iron oxide, and silica oxide, are found in many chemical, cosmetic, pharmaceutical, and electronic products. Recently, SiO2 nanoparticles were shown to have an inert toxicity profile and no association with an irreversible toxicological change in animal models. Hence, exposure to SiO2 nanoparticles is on the increase. SiO2 nanoparticles are routinely used in numerous materials, from strengthening filler for concrete and other construction composites, to nontoxic platforms for biomedical application, such as drug delivery and theragnostics. On the other hand, recent in vitro experiments indicated that SiO2 nanoparticles were cytotoxic. Therefore, we investigated these nanoparticles to identify potentially toxic pathways by analyzing the adsorbed protein corona on the surface of SiO2 nanoparticles in the blood and brain of the rat. Four types of SiO2 nanoparticles were chosen for investigation, and the protein corona of each type was analyzed using liquid chromatography-tandem mass spectrometry technology. In total, 115 and 48 plasma proteins from the rat were identified as being bound to negatively charged 20 nm and 100 nm SiO2 nanoparticles, respectively, and 50 and 36 proteins were found for 20 nm and 100 nm arginine-coated SiO2 nanoparticles, respectively. Higher numbers of proteins were adsorbed onto the 20 nm sized SiO2 nanoparticles than onto the 100 nm sized nanoparticles regardless of charge. When proteins were compared between the two charges, higher numbers of proteins were

  19. Modified Tumescent Solution for Creating Working Space During Endoscopic Thyroidectomy.

    Science.gov (United States)

    Zhang, Li-Yong; Zhao, Wen-Xin; Wang, Bo; Yan, Shou-Yi; Wen, Jia

    2018-04-01

    To study the feasibility of gas-liquid mixing tumescent solution for creating a working space (WS) in endoscopic thyroidectomy (ET). A prospective study was performed on 186 patients with thyroid tumor who had undergone ET via chest and breast approach. Patients were randomly divided into 2 groups to receive traditional tumescent solution as group A and modified tumescent solution (gas-liquid mixing tumescent solution) as group B. This study compares the following surgical outcome parameters between the 2 groups, including changes of blood pressure, heart rate, and oxygen saturation before and after creating a WS, time for creating a WS, operative time, hemorrhage volume for creating a WS, overall hemorrhage volume, overall postoperative drainage volume, postoperative pain score, postoperative hospitalization, number of retrieved lymph nodes, total serum calcium, serum parathyroid hormone, and cases of transient and permanent recurrent laryngeal nerve palsy. No postoperative bleeding, permanent recurrent laryngeal nerve palsy, incision and surgical site infection, air embolism, flap injury occurred in both groups. The mean time for creating a WS and the whole operation in group B was significantly shorter than that in group A ( P .05). The clinical application of gas-liquid mixing tumescent solution can effectively reduce the time for creating a WS and whole operative time, and worthy of being widely used in ET as a safe and effective technique.

  20. Create a new vision for indigenous development

    Energy Technology Data Exchange (ETDEWEB)

    Chavez Alba, Rafael; Sanchez Arancibia, Oscar Armando [TRANSIERRA S.A., Santa Cruz (Bolivia)

    2009-07-01

    Transierra is a Bolivian company created in the year 2000 with the goal of transporting natural gas from the fields of San Alberto and San Antonio, in Tarija, to the Rio Grande Gas Compression Plant in Santa Cruz, for export to Brazil. Transierra has implemented a Social Action Plan, which allowed it to execute more than 800 community projects for the benefit of over 40 thousand families living in it's area of influence, with the presence of 146 indigenous communities, generally lagging behind in economic and productive life in the region and country. The Support Program to Guarani Development Plans (PA-PDG) is part of the Social Plan and is part of a long-term agreement signed between Transierra and indigenous organizations. The program has implemented more than one hundred projects for productive development, health, education, cultural revaluation, and strengthening organizational infrastructure, generating huge benefits in improving the living conditions of thousands of families of the Guarani people. This year a unique initiative was created with 4 Indigenous Captains and with the support of the International Finance Corporation (World Bank Group), including Business Plans to promote sustainable economic growth, created productive economic cycles involving improvements to the production and productivity to enter the commercial distribution of local and national markets. These four initiatives have meant a shift in the implementation and is helping to generate new dynamics in production, in addition to capturing significant resources from public and private investment, laying the groundwork for the improvement of the incomes and quality of life of its beneficiaries. (author)

  1. Development of nano SiO2 incorporated nano zinc phosphate coatings on mild steel

    International Nuclear Information System (INIS)

    Tamilselvi, M.; Kamaraj, P.; Arthanareeswari, M.; Devikala, S.; Selvi, J. Arockia

    2015-01-01

    Highlights: • Nano SiO 2 incorporated nano zinc phosphate coating on mild steel was developed. • Coatings showed enhanced corrosion resistance. • The nano SiO 2 is adsorbed on mild steel surface and become nucleation sites. • The nano SiO 2 accelerates the phosphating process. - Abstract: This paper reports the development of nano SiO 2 incorporated nano zinc phosphate coatings on mild steel at low temperature for achieving better corrosion protection. A new formulation of phosphating bath at low temperature with nano SiO 2 was attempted to explore the possibilities of development of nano zinc phosphate coatings on mild steel with improved corrosion resistance. The coatings developed were studied by Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Electrochemical measurements. Significant variation in the coating weight, morphology and corrosion resistance was observed as nano SiO 2 concentrations varied from 0.5–4 g/L. The results showed that, the nano SiO 2 in the phosphating solution changed the initial potential of the interface between mild steel substrate and phosphating solution and reduce the activation energy of the phosphating process, increase the nucleation sites and yielded zinc phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance. Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano SiO 2 . The new formulation reported in the present study was free from Ni or Mn salts and had very low concentration of sodium nitrite (0.4 g/L) as accelerator

  2. Nano-Ticl 4 .SiO 2 : a Versatile and Efficient Catalyst for Synthesis of ...

    African Journals Online (AJOL)

    Nano-TiCl4.SiO2 has been found to be an extremely efficient catalyst for the preparation of 3,4-dihydropyrimidinones/thiones via three-component reactions of an aldehyde, β-ketoester or β-diketone and urea or thiourea under mild conditions. Nano-TiCl4.SiO2 as a solid Lewis acid has been synthesized by reaction of ...

  3. SiO2@TiO2 Coating: Synthesis, Physical Characterization and Photocatalytic Evaluation

    Directory of Open Access Journals (Sweden)

    A. Rosales

    2018-03-01

    Full Text Available Use of silicon dioxide (SiO2 and titanium dioxide (TiO2 have been widely investigated individually in coatings technology, but their combined properties promote compatibility for different innovative applications. For example, the photocatalytic properties of TiO2 coatings, when exposed to UV light, have interesting environmental applications, such as air purification, self-cleaning and antibacterial properties. However, as reported in different pilot projects, serious durability problems, associated with the adhesion between the substrate and TiO2, have been evidenced. Thus, the aim of this work is to synthesize SiO2 together with TiO2 to increase the durability of the photocatalytic coating without affecting its photocatalytic potential. Therefore, synthesis using sonochemistry, synthesis without sonochemistry, physical characterization, photocatalytic evaluation, and durability of the SiO2, SiO2@TiO2 and TiO2 coatings are presented. Results indicate that using SiO2 improved the durability of the TiO2 coating without affecting its photocatalytic properties. Thus, this novel SiO2@TiO2 coating shows potential for developing long-lasting, self-cleaning and air-purifying construction materials.

  4. Positron annihilation in SiO 2-Si studied by a pulsed slow positron beam

    Science.gov (United States)

    Suzuki, R.; Ohdaira, T.; Uedono, A.; Kobayashi, Y.

    2002-06-01

    Positron and positronium (Ps) behavior in SiO 2-Si have been studied by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The PALS study of SiO 2-Si samples, which were prepared by a dry-oxygen thermal process, revealed that the positrons implanted in the Si substrate and diffused back to the interface do not contribute to the ortho-Ps long-lived component, and the lifetime spectrum of the interface has at least two components. From the AMOC study, the momentum distribution of the ortho-Ps pick-off annihilation in SiO 2, which shows broader momentum distribution than that of crystalline Si, was found to be almost the same as that of free positron annihilation in SiO 2. A varied interface model was proposed to interpret the results of the metal-oxide-semiconductor (MOS) experiments. The narrow momentum distribution found in the n-type MOS with a negative gate bias voltage could be attributed to Ps formation and rapid spin exchange in the SiO 2-Si interface. We have developed a two-dimensional positron lifetime technique, which measures annihilation time and pulse height of the scintillation gamma-ray detector for each event. Using this technique, the positronium behavior in a porous SiO 2 film, grown by a sputtering method, has been studied.

  5. Effect of SiO2 passivation overlayers on hillock formation in Al thin films

    International Nuclear Information System (INIS)

    Kim, Deok-kee

    2012-01-01

    Hillock formation in Al thin films with varying thicknesses of SiO 2 as a passivation layer was investigated during thermal cycling. Based on the stress measurements and the number of hillocks, 250 nm thick SiO 2 was thick enough to suppress the hillock formation and the suppression of hillock at 250 nm passivation and the lack of suppression at thinner passivation is related to the presence/absence of protection against the diffusive flow of atoms from the surrounding area to the surface due to the biaxial compressive stresses present in the film through the weak spots in the passivation layer. The stress state of Al films measured during annealing (the driving force for hillock formation) did not vary much with SiO 2 thickness. A small number of hillocks formed during the plasma enhanced chemical vapor deposition of SiO 2 overlayers at 300 °C. - Highlights: ► We examined the effect of SiO 2 overlayers on hillock formation in Al thin films. ► Thin overlayers were not effective in suppressing diffusive flow to the surface. ► A thick overlayer suppressed the diffusive flow from the interior to the surface. ► The stress state of Al films did not vary much with SiO 2 passivation thickness. ► High mechanical strength provided a large driving force for the large grain growth.

  6. Screen-Printed Photochromic Textiles through New Inks Based on SiO2@naphthopyran Nanoparticles.

    Science.gov (United States)

    Pinto, Tânia V; Costa, Paula; Sousa, Céu M; Sousa, Carlos A D; Pereira, Clara; Silva, Carla J S M; Pereira, Manuel Fernando R; Coelho, Paulo J; Freire, Cristina

    2016-10-26

    Photochromic silica nanoparticles (SiO 2 @NPT), fabricated through the covalent immobilization of silylated naphthopyrans (NPTs) based on 2H-naphtho[1,2-b]pyran (S1, S2) and 3H-naphtho[2,1-b]pyran (S3, S4) or through the direct adsorption of the parent naphthopyrans (1, 3) onto silica nanoparticles (SiO 2 NPs), were successfully incorporated onto cotton fabrics by a screen-printing process. Two aqueous acrylic- (AC-) and polyurethane- (PU-) based inks were used as dispersing media. All textiles exhibited reversible photochromism under UV and solar irradiation, developing fast responses and intense coloration. The fabrics coated with SiO 2 @S1 and SiO 2 @S2 showed rapid color changes and high contrasts (ΔE* ab = 39-52), despite presenting slower bleaching kinetics (2-3 h to fade to the original color), whereas the textiles coated with SiO 2 @S3 and SiO 2 @S4 exhibited excellent engagement between coloration and decoloration rates (coloration and fading times of 1 and 2 min, respectively; ΔE* ab = 27-53). The PU-based fabrics showed excellent results during the washing fastness tests, whereas the AC-based textiles evidenced good results only when a protective transfer film was applied over the printed design.

  7. SiO2 stabilized Pt/C cathode catalyst for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Zhu Tong; Du Chunyu; Liu Chuntao; Yin Geping; Shi Pengfei

    2011-01-01

    This paper describes the preparation of SiO 2 stabilized Pt/C catalyst (SiO 2 /Pt/C) by the hydrolysis of alkoxysilane, and examines the possibility that the SiO 2 /Pt/C is used as a durable cathode catalyst for proton exchange membrane fuel cells (PEMFCs). TEM and XRD results revealed that the hydrolysis of alkoxysilane did not significantly change the morphology and crystalline structure of Pt particles. The SiO 2 /Pt/C catalyst exhibited higher durability than the Pt/C one, due to the facts that the silica layers covered were beneficial for reducing the Pt aggregation and dissolution as well as increasing the corrosion resistance of supports, although the benefit of silica covering was lower than the case of Pt/CNT catalyst. Also, it was observed that the activity of the SiO 2 /Pt/C catalyst for the oxygen reduction reaction was somewhat reduced compared to the Pt/C one after the silica covering. This reduction was partially due to the low oxygen kinetics as revealed by the rotating-disk-electrode measurement. Silica covering by hydrolysis of only 3-aminopropyl trimethoxysilane is able to achieve a good balance between the durability and activity, leading to SiO 2 /Pt/C as a promising cathode catalyst for PEMFCs.

  8. Microwave electromagnetic and absorption properties of SiO2/C core/shell composites plated with metal cobalt

    Science.gov (United States)

    Shen, Guozhu; Fang, Xumin; Wu, Hongyan; Wei, Hongyu; Li, Jingfa; Li, Kaipeng; Mei, Buqing; Xu, Yewen

    2017-04-01

    A facile method has been developed to fabricate magnetic core/shell SiO2/C/Co sub-microspheres via the pyrolysis of SiO2/PANI (polyaniline) and electroless plating method. The electromagnetic parameters of these SiO2/C and SiO2/C/Co composites were measured and the microwave reflection loss properties were evaluated in the frequency range of 2-18 GHz. The results show that the dielectric loss of SiO2/C composite increases with the increase of carbonization temperature and the magnetic loss enhances due to the deposition of cobalt on the SiO2/C sub-microspheres. The reflection loss results exhibit that the microwave absorption properties of the SiO2/C/Co composites are more excellent than those of SiO2/C composites for each thickness. The maximum effective absorption bandwidth (reflection loss ≤ -10 dB) arrives at 5.0 GHz (13.0-18 GHz) for SiO2/C/Co composite with 1.5 mm of thickness and the minimum reflection loss value is -24.0 dB at 5.0 GHz with 4.0 mm of thickness. The microwave loss mechanism of the SiO2/C/Co composites was also discussed in this paper.

  9. Effect of Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O Promoter Catalysts on H2, CO and CH4 Concentration by CO2 Gasification of Rosa Multiflora Biomass

    Directory of Open Access Journals (Sweden)

    Tursunov Obid

    2017-11-01

    Full Text Available The thermal behaviour of the Rosa mutiflora biomass by thermogravimetric analysis was studied at heating rate 3 K min−1 from ambient temperature to 950 °C. TGA tests were performed in high purity carbon dioxide (99 998% with a flow rate 200 ml/min and 100 mg of sample, milled and sieved to a particle size below 250 µm. Moreover, yields of gasification products such as hydrogen (H2, carbon monoxide (CO and methane (CH4 were determined based on the thermovolumetric measurements of catalytic (Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O promoter catalysts and non-catalytic gasification of the Rosa multiflora biomass. Additionally, carbon conversion degrees are presented. Calculations were made of the kinetic parameters of carbon monoxide and hydrogen formation reaction in the catalytic and non-catalytic CO2 gasification processes. A high temperature of 950 °C along with Ni/Al2O3-SiO2and Ni/Al2O3-SiO2 with K2O promoter catalysts resulted in a higher conversion of Rosa multiflora biomass into gaseous yield production with greatly increasing of H2 and CO contents. Consequently, H2 and CO are the key factors to produce renewable energy and bio-gases (synthesis gas. The parameters obtained during the experimental examinations enable a tentative assessment of plant biomasses for the process of large-scale gasification in industrial sectors.

  10. Creating Interdisciplinarity within Monodisciplinary Structures

    DEFF Research Database (Denmark)

    Lindvig, Katrine

    discrepancies in the use of the term interdisciplinarity, which have repercussions for the practices and incentives of creating interdisciplinary education, research and collaboration. Overall, the thesis shows that interdisciplinary teaching and learning practices have to engage in a continuous balancing...

  11. Positive effects of creating mandalas

    OpenAIRE

    Toroš, Maja

    2016-01-01

    The purpose of the present master’s thesis is to examine the psychological effects of creating mandalas and to give recommendations for a better use of the mandalas in the practice of art assistance in order to help in this way others and oneself. Mandalas are sacred symbols, used in Hinduism and Buddhist religion practices as tools for meditation and concentration. They are geometrical representations of the creation of the cosmos and schemas of all that was created. Jung sat the foundations...

  12. Creating visual explanations improves learning.

    Science.gov (United States)

    Bobek, Eliza; Tversky, Barbara

    2016-01-01

    Many topics in science are notoriously difficult for students to learn. Mechanisms and processes outside student experience present particular challenges. While instruction typically involves visualizations, students usually explain in words. Because visual explanations can show parts and processes of complex systems directly, creating them should have benefits beyond creating verbal explanations. We compared learning from creating visual or verbal explanations for two STEM domains, a mechanical system (bicycle pump) and a chemical system (bonding). Both kinds of explanations were analyzed for content and learning assess by a post-test. For the mechanical system, creating a visual explanation increased understanding particularly for participants of low spatial ability. For the chemical system, creating both visual and verbal explanations improved learning without new teaching. Creating a visual explanation was superior and benefitted participants of both high and low spatial ability. Visual explanations often included crucial yet invisible features. The greater effectiveness of visual explanations appears attributable to the checks they provide for completeness and coherence as well as to their roles as platforms for inference. The benefits should generalize to other domains like the social sciences, history, and archeology where important information can be visualized. Together, the findings provide support for the use of learner-generated visual explanations as a powerful learning tool.

  13. Gas utilization technologies

    International Nuclear Information System (INIS)

    Biljetina, R.

    1994-01-01

    One of the constant challenges facing the research community is the identification of technology needs 5 to 15 years from now. A look back into history indicates that the forces driving natural gas research have changed from decade to decade. In the 1970s research was driven by concerns for adequate supply; in the 1980s research was aimed at creating new markets for natural gas. What then are the driving forces for the 1990s? Recent reports from the natural gas industry have helped define a new direction driven primarily by market demand for natural gas. A study prepared by the Interstate Natural Gas Association of America Foundation entitled ''Survey of Natural Research, Development, and Demonstration RD ampersand D Priorities'' indicated that in the 1990s the highest research priority should be for natural gas utilization and that technology development efforts should not only address efficiency and cost, but environmental and regulatory issues as well. This study and others, such as the report by the American Gas Association (A.G.A.) entitled ''Strategic Vision for Natural Gas Through the Year 2000,'' clearly identify the market sectors driving today's technology development needs. The biggest driver is the power generation market followed by the industrial, transportation, appliance, and gas cooling markets. This is best illustrated by the GRI 1994 Baseline Projection on market growth in various sectors between the year 1992 and 2010. This paper highlights some of the recent technology developments in each one of these sectors

  14. Potential energy landscape of an interstitial O2 molecule in a SiO2 film near the SiO2/Si(001) interface

    Science.gov (United States)

    Ohta, Hiromichi; Watanabe, Takanobu; Ohdomari, Iwao

    2008-10-01

    Potential energy distribution of interstitial O2 molecule in the vicinity of SiO2/Si(001) interface is investigated by means of classical molecular simulation. A 4-nm-thick SiO2 film model is built by oxidizing a Si(001) substrate, and the potential energy of an O2 molecule is calculated at Cartesian grid points with an interval of 0.05 nm in the SiO2 film region. The result shows that the potential energy of the interstitial site gradually rises with approaching the interface. The potential gradient is localized in the region within about 1 nm from the interface, which coincides with the experimental thickness of the interfacial strained layer. The potential energy is increased by about 0.62 eV at the SiO2/Si interface. The result agrees with a recently proposed kinetic model for dry oxidation of silicon [Phys. Rev. Lett. 96, 196102 (2006)], which argues that the oxidation rate is fully limited by the oxidant diffusion.

  15. Thermal evolution of the morphology, structure, and optical properties of multilayer nanoperiodic systems produced by the vacuum evaporation of SiO and SiO2

    International Nuclear Information System (INIS)

    Ershov, A. V.; Chugrov, I. A.; Tetelbaum, D. I.; Mashin, A. I.; Pavlov, D. A.; Nezhdanov, A. V.; Bobrov, A. I.; Grachev, D. A.

    2013-01-01

    The alternate vacuum evaporation of SiO and SiO 2 from separate sources is used to produce amorphous a-SiO x /SiO 2 multilayer nanoperiodic structures with periods of 5–10 nm and a number of layers of up to 64. The effect of annealing at temperatures T a = 500–1100°C on the structural and optical properties of the nanostructures is studied. The results of transmission electron microscopy of the samples annealed at 1100°C indicate the annealing-induced formation of vertically ordered quasiperiodic arrays of Si nanocrystals, whose dimensions are comparable to the a-SiO x -layer thickness in the initial nanostructures. The nanostructures annealed at 1100°C exhibit size-dependent photoluminescence in the wavelength range 750–830 nm corresponding to Si nanocrystals. The data on infrared absorption and Raman scattering show that the thermal evolution of structural and phase state of the SiO x layers with increasing annealing temperature proceeds through the formation of amorphous Si nanoinclusions with the subsequent formation and growth of Si nanocrystals.

  16. Optical properties of the Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings

    Science.gov (United States)

    Marszałek, Konstanty; Winkowski, Paweł; Jaglarz, Janusz

    2014-01-01

    Investigations of bilayer and trilayer Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings are presented in this paper. The oxide films were deposited on a heated quartz glass by e-gun evaporation in a vacuum of 5 × 10-3 [Pa] in the presence of oxygen. Depositions were performed at three different temperatures of the substrates: 100 °C, 200 °C and 300 °C. The coatings were deposited onto optical quartz glass (Corning HPFS). The thickness and deposition rate were controlled with Inficon XTC/2 thickness measuring system. Deposition rate was equal to 0.6 nm/s for Al2O3, 0.6 nm - 0.8 nm/s for HfO2 and 0.6 nm/s for SiO2. Simulations leading to optimization of the thin film thickness and the experimental results of optical measurements, which were carried out during and after the deposition process, have been presented. The optical thickness values, obtained from the measurements performed during the deposition process were as follows: 78 nm/78 nm for Al2O3/SiO2 and 78 nm/156 nm/78 nm for Al2O3/HfO2/SiO2. The results were then checked by ellipsometric technique. Reflectance of the films depended on the substrate temperature during the deposition process. Starting from 240 nm to the beginning of visible region, the average reflectance of the trilayer system was below 1 % and for the bilayer, minima of the reflectance were equal to 1.6 %, 1.15 % and 0.8 % for deposition temperatures of 100 °C, 200 °C and 300 °C, respectively.

  17. Tunable graphene doping by modulating the nanopore geometry on a SiO2/Si substrate

    KAUST Repository

    Lim, Namsoo

    2018-02-28

    A tunable graphene doping method utilizing a SiO2/Si substrate with nanopores (NP) was introduced. Laser interference lithography (LIL) using a He–Cd laser (λ = 325 nm) was used to prepare pore size- and pitch-controllable NP SiO2/Si substrates. Then, bottom-contact graphene field effect transistors (G-FETs) were fabricated on the NP SiO2/Si substrate to measure the transfer curves. The graphene transferred onto the NP SiO2/Si substrate showed relatively n-doped behavior compared to the graphene transferred onto a flat SiO2/Si substrate, as evidenced by the blue-shift of the 2D peak position (∼2700 cm−1) in the Raman spectra due to contact doping. As the porosity increased within the substrate, the Dirac voltage shifted to a more positive or negative value, depending on the initial doping type (p- or n-type, respectively) of the contact doping. The Dirac voltage shifts with porosity were ascribed mainly to the compensation for the reduced capacitance owing to the SiO2–air hetero-structured dielectric layer within the periodically aligned nanopores capped by the suspended graphene (electrostatic doping). The hysteresis (Dirac voltage difference during the forward and backward scans) was reduced when utilizing an NP SiO2/Si substrate with smaller pores and/or a low porosity because fewer H2O or O2 molecules could be trapped inside the smaller pores.

  18. Non-LTE Analysis of Interstellar Line Spectra of SiO

    Science.gov (United States)

    Zhang, Ziwei; Stancil, Phillip C.

    2016-01-01

    SiO emission lines are important probes of chemical processes in diverse astrophysical environments. In circumstellar outflows of AGB stars, the production of silicate grains is preceded by SiO formation, making SiO a useful measure of Si depletion. SiO is also commonly observed in shocks associated with the outflows of young stellar objects, both low- and high-mass. To model SiO emission for non-LTE conditions requires collisional rate coefficients due to H2 impact which are currently unavailable. Unknown collisional rate coefficients are often estimated from known systems. For the case of SiO-H2, rate coefficients have previously been adapted from a different collider, He (Dayau & Balanca 2006), based on a reduced-mass scaling approach. Recently it has been suggested that scaling via the interaction potential well depth and the reduced masses of the collisional systems may be more reliable (Walker et al. 2014). Using the non-LTE spectral modeling package Radex (van der Tak et al. 2007), we construct diagnostic plots of SiO line ratios using SiO-H2 collisional rate coefficients based on (i) reduced-mass scaling from the LAMDA database, (ii) potential well-depth scaling, and (iii) a more comprehensive input with multiple colliders (H2, He and H). Our goal is to give a more rigorous approach to SiO line emission simulations to better understand Si chemistry, dust formation/destruction, and other astrophysical processes.This work was supported by NASA ATP grant NNX15AI61G.

  19. Ultracold gas shows 'lopsided' properties

    CERN Multimedia

    2002-01-01

    "Duke University researchers have created an ultracold gas that has the startling property of bursting outward in a preferred direction when released. According to the researchers, studying the properties of the "lopsided" gas will yield fundamental insights into how matter holds itself together at the subatomic level" (1 page).

  20. Creating a sustainable energy future for Australia

    International Nuclear Information System (INIS)

    Sonneborn, C.L.

    1995-01-01

    A joint industry approach is needed to put in place a sustainable energy system that is economically and technologically feasible. The industry sectors involved must include the renewable energy industry, energy efficiency industry and the natural gas industry. Conventional forecasts of energy futures make far less use of these industries than is economically and technically feasible. Existing forecasts make the trade off between acceptable levels of economic growth, limitation of greenhouse gases and dependence on coal and oil appear more difficult than they actually are and overlook the benefits of sustainable energy industry development. This paper outlines how national gains from carefully targeted action can exceed national losses while substantially reducing greenhouse gases and creating jobs at zero or negative costs. (author). 3 figs., 27 refs

  1. Deployment and future prospects of high performance diagnostics featuring serial I/O (SIO) data acquisition (DAQ) at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Behler, K., E-mail: karl.behler@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Blank, H.; Eixenberger, H. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Fitzek, M. [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, D-82393 Iffeldorf (Germany); Lohs, A. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Lueddecke, K. [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, D-82393 Iffeldorf (Germany); Merkel, R. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The high sustained data rates transferring measured data from periphery into memory of computers. Black-Right-Pointing-Pointer The achieved low latency in real-time interrupt handling under Solaris 10. Black-Right-Pointing-Pointer The new prototype of an even more powerful 2nd generation SIO II device. Black-Right-Pointing-Pointer The fusion of all blocks of board logic (serializer, FIFO, TDC, merge engine, PCIe controller) into one single FPGA simplifying the boards physical layout significantly. - Abstract: The SIO DAQ concept used at the ASDEX Upgrade fusion experiment features data acquisition from a modular front-end (a modular crate-and-interface-cards concept for analog and digital input and output) over standardized serial lines and via a serial input/output computer interface card (the SIO card) in real-time directly into the main memory of a host computer. Deployment of a series of diagnostics using SIO led to various solutions and configurations for the different requirements. Experience has been gained and lessons learned applying the SIO concept at its technical limits. Requirements for a further development of the SIO concept have been identified, and a performance improvement by a factor of 4-8 beyond its current limits seems achievable. An effort has been started to develop a SIO version 2 (SIO II) featuring upgraded serial links and a more powerful FPGA for merging and forwarding data streams to host computer memory. (Compatibility with the existing SIO (SIO I) front-end system has to be maintained.) This paper presents results achieved and experiences gained in the deployment of SIO I, the status of SIO II development (currently in the prototype phase), and projected enhancements and updates to existing implementations.

  2. On Creating and Sustaining Alternatives

    DEFF Research Database (Denmark)

    Kyng, Morten

    2015-01-01

    This paper presents and discusses an initiative aimed at creating direct and long lasting influence on the use and development of telemedicine and telehealth by healthcare professionals, patients and citizens. The initiative draws on ideas, insights, and lessons learned from Participatory Design...... (PD) as well as from innovation theory and software ecosystems. Last, but not least, the ongoing debate on public finances/economy versus tax evasion by major private companies has been an important element in shaping the vision and creating support for the initiative. This vision is about democratic...

  3. Journaling: creating space for "I".

    Science.gov (United States)

    Charles, Jennell P

    2010-01-01

    As nurses engaged in a caring profession, it is critical that we learn not only to care for others but also to care for ourselves. To care effectively for ourselves, we must create the space and time in which to do this. Journaling is one tool that scholars offer as a way to create this space. Although there is no clear consensus about the best techniques for journaling, there is evidence that journaling, as a reflective, meditative activity, can promote creativity, self-awareness, and personal development.

  4. Densification of ∼5 nm-thick SiO_2 layers by nitric acid oxidation

    International Nuclear Information System (INIS)

    Choi, Jaeyoung; Joo, Soyeong; Park, Tae Joo; Kim, Woo-Byoung

    2017-01-01

    Highlights: • Leakage current density of the commercial PECVD grown ∼5 nm SiO_2 layer has been decreased about three orders of magnitude by densification. • The densification of SiO_2 layer is achieved by high oxidation ability of O·. • Densities of suboxide, fixed charge (N_f) and defect state (N_d) in SiO_2/Si interface are decreased by NAOS and PMA. • Tunneling barrier height (Φ_t) is increased because of the increase of atomic density in SiO_2 layer. - Abstract: Low-temperature nitric acid (HNO_3) oxidation of Si (NAOS) has been used to improve the interface and electrical properties of ∼5 nm-thick SiO_2/Si layers produced by plasma-enhanced chemical vapor deposition (PECVD). Investigations of the physical properties and electrical characteristics of these thin films revealed that although their thickness is not changed by NAOS, the leakage current density at a gate bias voltage of −1 V decreases by about two orders of magnitude from 1.868 × 10"−"5 A/cm"2. This leakage current density was further reduced by post-metallization annealing (PMA) at 250 °C for 10 min in a 5 vol.% hydrogen atmosphere, eventually reaching a level (5.2 × 10"−"8 A/cm"2) approximately three orders of magnitude less than the as-grown SiO_2 layer. This improvement is attributed to a decrease in the concentration of suboxide species (Si"1"+, Si"2"+ and Si"3"+) in the SiO_2/Si interface, as well as a decrease in the equilibrium density of defect sites (N_d) and fixed charge density (N_f). The barrier height (Φ_t) generated by a Poole-Frenkel mechanism also increased from 0.205 to 0.371 eV after NAOS and PMA. The decrease in leakage current density is therefore attributed to a densification of the SiO_2 layer in combination with the removal of OH species and increase in interfacial properties at the SiO_2/Si interface.

  5. Cd2SiO4/Graphene nanocomposite: Ultrasonic assisted synthesis, characterization and electrochemical hydrogen storage application.

    Science.gov (United States)

    Masjedi-Arani, Maryam; Salavati-Niasari, Masoud

    2018-05-01

    For the first time, a simple and rapid sonochemical technique for preparing of pure Cd 2 SiO 4 nanostructures has been developed in presence of various surfactants of SDS, CTAB and PVP. Uniform and fine Cd 2 SiO 4 nanoparticle was synthesized using of polymeric PVP surfactant and ultrasonic irradiation. The optimized cadmium silicate nanostructures added to graphene sheets and Cd 2 SiO 4 /Graphene nanocomposite synthesized through pre-graphenization. Hydrogen storage capacity performances of Cd 2 SiO 4 nanoparticle and Cd 2 SiO 4 /Graphene nanocomposite were compared. Obtained results represent that Cd 2 SiO 4 /Graphene nanocomposites have higher hydrogen storage capacity than Cd 2 SiO 4 nanoparticles. Cd 2 SiO 4 /Graphene nanocomposites and Cd 2 SiO 4 nanoparticles show hydrogen storage capacity of 3300 and 1300 mAh/g, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Structural colors of the SiO2/polyethyleneimine thin films on poly(ethylene terephthalate) substrates

    International Nuclear Information System (INIS)

    Jia, Yanrong; Zhang, Yun; Zhou, Qiubao; Fan, Qinguo; Shao, Jianzhong

    2014-01-01

    The SiO 2 /polyethyleneimine (PEI) films with structural colors on poly(ethylene terephthalate) (PET) substrates were fabricated by an electrostatic self-assembly method. The morphology of the films was characterized by Scanning Electron Microscopy. The results showed that there was no distinguishable multilayered structure found of SiO 2 /PEI films. The optical behaviors of the films were investigated through the color photos captured by a digital camera and the color measurement by a multi-angle spectrophotometer. Different hue and brightness were observed at various viewing angles. The structural colors were dependent on the SiO 2 particle size and the number of assembly cycles. The mechanism of the structural colors generated from the assembled films was elucidated. The morphological structures and the optical properties proved that the SiO 2 /PEI film fabricated on PET substrate formed a homogeneous inorganic/organic SiO 2 /PEI composite layer, and the structural colors were originated from single thin film interference. - Highlights: • SiO 2 /PEI thin films were electrostatic self-assembled on PET substrates. • The surface morphology and optical behavior of the film were investigated. • The structural colors varied with various SiO 2 particle sizes and assembly cycles. • Different hue and lightness of SiO 2 /PEI film were observed at various viewing angles. • Structural color of the SiO 2 /PEI film originated from single thin film interference

  7. More accurate definition of liquation dome in Na2O-B2O3-SiO2 system

    International Nuclear Information System (INIS)

    Alekseeva, Z.D.; Mazurin, O.V.; Aver'yanov, V.I.; Galakhov, F.Ya.

    1977-01-01

    The liquation region in the system Na 2 O-B 2 O 3 -SiO 2 was investigated. The liquation temperatures were determined by the boundary of disappearance of opalescence in specimens with pre-induced opalescence. Extrapolation of the concentration dependences of the liquation temperature along sections with a constant SiO 2 content to a point indicates that with a SiO 2 content of 20-40% the liquation boundary in the system B 2 O 3 -SiO 2 hardly lies above 450 deg C

  8. 1962 : Bay City gas

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    In 1962, a major natural gas export system from Alberta to San Francisco was brought online. The $300 million, 2,200 km Alberta and Southern system was expected to transport 584 million cubic feet daily in its first year of operation, more than one-third the total volume of gas sold by Canadian producers the previous year. The new gas export market also served to create more gas for the Canadian market because the incentive to serve a large export market also encouraged producers to explore for and develop more gas. The pipeline system started in the foothills belt 200 km northwest of Edmonton, and spanned through Idaho, Washington, Oregon and California. One month before its official opening, a gas line explosion occurred during pressure testing of a lateral line. The Alberta portion of the Alberta and Southern system was also used 2 decades later as a tie-in to the Alaska Highway Gas Pipeline project. Other key events in 1962 included approval of the Great Canadian Oil Sands Limited; the manufacture of the first rock drill bits in western Canada; production of 90 million cubic feet of natural gas from 12 wells in Quebec; and, an increase in oil production from the Soviet Union. 1 tab., 1 fig

  9. Investigation of TL, OSL and PTTL properties of Mg2SiO4:Tb dosimeters

    International Nuclear Information System (INIS)

    Oguz, K. F.; Goekce, M.; Karali, T.; Harmansah, C.

    2010-01-01

    In this study thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of Mg 2 SiO 4 :Tb in the form of sintered pellets were investigated. Mg 2 SiO 4 :Tb is a recently developed dosimetric material which offers high sensitivity for TL and OSL in dosimetric applications. Thermoluminescence glow curve of Tb doped Mg 2 SiO 4 samples show a glow peak at about 200 degree Celsius with two small peaks at about 275 and 330 degree Celsius, respectively. OSL experiments showed that blue light (470 nm) is six times more efficient than green light (532 nm) to stimulate the OSL emission. The aim of this study was to determine the TL and OSL fading properties of Mg 2 SiO 4 : Tb using OSL and TL methods. In addition, PTTL properties of the Mg 2 SiO 4 : Tb was investigated by using blue LEDs, UV lamp and blue laser. Investigations on the fading properties also showed that the TL signal fades % 10 in a period of 1 month and OSL signal fades % 10 in a period of 3 month, which then the signal remains relatively stable for longer periods.

  10. Growth and characterization of Nd:Bi12SiO20 single crystal

    Science.gov (United States)

    Xu, Honghao; Zhang, Yuanyuan; Zhang, Huaijin; Yu, Haohai; Pan, Zhongben; Wang, Yicheng; Sun, Shangqian; Wang, Jiyang; Boughton, R. I.

    2012-09-01

    A Nd:Bi12SiO20 crystal was grown by the Czochralski method. The thermal properties of the crystal were systematically studied. The thermal expansion coefficient was measured to be α=11.42×10-6 K-1 over the temperature range of 295-775 K, and the specific heat and thermal diffusion coefficient were measured to be 0.243 Jg-1 k-1 and 0.584 mm2/s, respectively at 302 K. The density was measured to be 9.361 g/cm3 by the buoyancy method. The thermal conductivity of Nd:Bi12SiO20 was calculated to be 1.328 Wm-1 K-1 at room temperature (302 K). The refractive index of Nd:Bi12SiO20 was measured at room temperature at eight different wavelengths. The absorption and emission spectra were also measured at room temperature. Continuous-wave (CW) laser output of a Nd:Bi12SiO20 crystal pumped by a laser diode (LD) at 1071.5 nm was achieved with an output power of 65 mW. To our knowledge, this is the first time LD pumped laser output in this crystal has been obtained. These results show that Nd:Bi12SiO20 can serve as a laser crystal.

  11. Towards understanding the thermoanalysis of water sorption on lithium orthosilicate (Li4SiO4)

    International Nuclear Information System (INIS)

    Ortiz-Landeros, J.; Martinez-dlCruz, L.; Gomez-Yanez, C.; Pfeiffer, H.

    2011-01-01

    A systematic thermogravimetric study of hygroscopic and reactivity behaviors, at low temperatures of lithium orthosilicate (Li 4 SiO 4 ), are presented. Li 4 SiO 4 sample was prepared by solid-state reaction and then treated at different temperature-humidity conditions. Li 4 SiO 4 samples previously treated under different temperature-humidity conditions were characterized by Fourier transform infrared spectroscopy and thermogravimetric analyses. Different processes, adsorption and absorption, take place between the Li 4 SiO 4 and water vapor. Absorbed water produces superficial hydroxylated species such as Si-OH and Li-OH. In addition, a kinetic analysis was performed, and the different water absorption activation enthalpies were calculated. It was found that activation enthalpy (ΔH) values decrease when the relative humidity is incremented, from 5528.6 J/mol to 2074.2 J/mol at relative humidity levels of 60% and 75% respectively. These results show the impact of different humidity and temperature conditions on the stability and/or chemical reactivity of Li 4 SiO 4 , if this ceramic is used in different application fields, such as carbon dioxide captor or as a breeder ceramic into the fusion reactors.

  12. SiO2-induced release of sVEGFRs from pulmonary macrophages.

    Science.gov (United States)

    Chao, Jie; Lv, Yan; Chen, Jin; Wang, Jing; Yao, Honghong

    2018-01-01

    The inhalation of silicon dioxide (SiO 2 ) particles causes silicosis, a stubborn pulmonary disease that is characterized by alveolar inflammation during the early stage. Soluble cytokine receptors (SCRs) play important roles in regulating inflammation by either attenuating or promoting cytokine signaling. However, the role of SCRs in silicosis remains unknown. Luminex assays revealed increased soluble vascular endothelial growth factor receptor (sVEGFR) family levels in the plasma of silicosis patients. In an enzyme-linked immunosorbent assay (ELISA), cells from the differentiated human monocytic cell line U937 released sVEGFR family proteins after exposure to SiO 2 (50μg/cm 2 ). Further Western blot experiments revealed that VEGFR expression was also elevated in U937 cells. In contrast, levels of sVEGFR family members did not change in the supernatants of human umbilical vein endothelial cells (HUVECs) after exposure to SiO 2 (50μg/cm 2 ). Interestingly, VEGFR expression in HUVECs decreased after SiO 2 treatment. In a scratch assay, HUVECs exhibited cell migration ability, indicating the acquisition of mesenchymal properties. Our findings highlight the important role of sVEGFRs in both inflammation and fibrosis induced by SiO 2 , suggesting a possible mechanism for the fibrogenic effects observed in pulmonary diseases associated with fibrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Transfer free graphene growth on SiO2 substrate at 250 °C

    Science.gov (United States)

    Vishwakarma, Riteshkumar; Rosmi, Mohamad Saufi; Takahashi, Kazunari; Wakamatsu, Yuji; Yaakob, Yazid; Araby, Mona Ibrahim; Kalita, Golap; Kitazawa, Masashi; Tanemura, Masaki

    2017-03-01

    Low-temperature growth, as well as the transfer free growth on substrates, is the major concern of graphene research for its practical applications. Here we propose a simple method to achieve the transfer free graphene growth on SiO2 covered Si (SiO2/Si) substrate at 250 °C based on a solid-liquid-solid reaction. The key to this approach is the catalyst metal, which is not popular for graphene growth by chemical vapor deposition. A catalyst metal film of 500 nm thick was deposited onto an amorphous C (50 nm thick) coated SiO2/Si substrate. The sample was then annealed at 250 °C under vacuum condition. Raman spectra measured after the removal of the catalyst by chemical etching showed intense G and 2D peaks together with a small D and intense SiO2 related peaks, confirming the transfer free growth of multilayer graphene on SiO2/Si. The domain size of the graphene confirmed by optical microscope and atomic force microscope was about 5 μm in an average. Thus, this approach will open up a new route for transfer free graphene growth at low temperatures.

  14. Thermodynamics of Bi2O3-SiO2 system

    Directory of Open Access Journals (Sweden)

    Onderka B.

    2017-01-01

    Full Text Available Thermodynamic properties of the liquid Bi2O3-SiO2 solutions were determined from the results of the electrochemical measurements by use of the solid oxide galvanic cells with YSZ (Yttria-Stabilized-Zirconia electrolyte. Activities of Bi2O3 in the solutions were determined for 0.2, 0.3, 0.4, and 0.5 SiO2 mole fractions in the temperature range 1073-1293 K from measured electromotive force (e.m.f of the solid electrolyte galvanic cell: Bi, Bi2O3-SiO2 | YSZ | air (pO2 = 0.213 bar Additionally, heat capacity data obtained for two solid phases 6Bi2O3•SiO2 and 2Bi2O3•3SiO2 were included into optimization of thermodynamic properties of the system. Optimization procedure was supported by differential thermal analysis (DTA data obtained in this work as well as those accepted from the literature. Using the data obtained in this work, and the information about phase equilibria found in the literature, binary system Bi2O3-SiO2 was assessed with the ThermoCalc software.

  15. Thermal SiO as a probe of high velocity motions in regions of star formation

    International Nuclear Information System (INIS)

    Downes, D.; Genzel, R.; Hjalmarson, A.; Nyman, L.A.; Roennaeng, B.

    1982-01-01

    New observations of the v = 0, J = = 2→1 line of SiO at 86.8 GHz show a close association of the thermal SiO emission and infrared and maser sources in regions of star formation. In addition to SiO emission with low velocity dispersion (Δν -1 ), we report the first detection of high velocity (''plateau'') emission toward W49 and W51. The low velocity SiO component may come from the core of the molecular cloud which contains the infrared and maser sources. The ''plateau'' may indicate mass clusters. In Orion KL, the positional centroid of the high velocity SiO emission (Vertical BarΔνVertical Bar> or =20 km s -1 ) is near that of the component we identify as the ''18 km s -1 flow''. However, the centriods of the blue- and redshifted wings are displaced from each other by a few arcseconds, to the NW and NE of the position of the 18 km s -1 component. The mass-loss rates of the high velocity flow and the 18 km s -1 flow are similar

  16. The improvement of SiO2 nanotubes electrochemical behavior by hydrogen atmosphere thermal treatment

    Science.gov (United States)

    Spataru, Nicolae; Anastasescu, Crina; Radu, Mihai Marian; Balint, Ioan; Negrila, Catalin; Spataru, Tanta; Fujishima, Akira

    2018-06-01

    Highly defected SiO2 nanotubes (SiO2-NT) were obtained by a simple sol-gel procedure followed by calcination. Boron-doped diamond (BDD) polycrystalline films coated with SiO2-NT were used as working electrodes and, unexpectedly, cyclic voltammetric experiments have shown that the concentration of both positive and negative defects at the surface is high enough to enable redox processes involving positively charged Ru(bpy)32+/3+ to occur. Conversely, no electrochemical activity was put into evidence for Fe(CN)63-/4- species, most likely as a result of the strong electrostatic repulsion exerted by the negatively charged SiO2 surface. The concentration of surface defects was further increased by a subsequent thermal treatment in a hydrogen atmosphere which, as EIS measurements have shown, significantly promotes Ru(bpy)32+ anodic oxidation. Digital simulation of the voltammetric responses demonstrated that this treatment does not lead to a similar increase of the number of electron-donor sites. It was also found that methanol anodic oxidation at hydrogenated SiO2-NT-supported platinum results in Tafel slopes of 116-220 mV decade-1, comparable to those reported for both conventional PtRu and Pt-oxide catalysts.

  17. Beyond sixfold coordinated Si in SiO2 glass at ultrahigh pressures.

    Science.gov (United States)

    Prescher, Clemens; Prakapenka, Vitali B; Stefanski, Johannes; Jahn, Sandro; Skinner, Lawrie B; Wang, Yanbin

    2017-09-19

    We investigated the structure of SiO 2 glass up to 172 GPa using high-energy X-ray diffraction. The combination of a multichannel collimator with diamond anvil cells enabled the measurement of structural changes in silica glass with total X-ray diffraction to previously unachievable pressures. We show that SiO 2 first undergoes a change in Si-O coordination number from fourfold to sixfold between 15 and 50 GPa, in agreement with previous investigations. Above 50 GPa, the estimated coordination number continuously increases from 6 to 6.8 at 172 GPa. Si-O bond length shows first an increase due to the fourfold to sixfold coordination change and then a smaller linear decrease up to 172 GPa. We reconcile the changes in relation to the oxygen-packing fraction, showing that oxygen packing decreases at ultrahigh pressures to accommodate the higher than sixfold Si-O coordination. These results give experimental insight into the structural changes of silicate glasses as analogue materials for silicate melts at ultrahigh pressures.

  18. Nondegradative Dielectric Coating of Graphene using Thermal Evaporation of SiO

    Science.gov (United States)

    Suzuki, Seiya; Lee, Chien-Chung; Nagamori, Takashi; Schibli, Thomas; Yoshimura, Masamichi

    2013-03-01

    Deposition of dielectrics onto graphene is a challenging technique due to the difficulties of fabricating high quality oxide on pristine graphene without introducing atomic defects. Here we report on a novel method to fabricate silicon oxide layer on graphene by vacuum thermal evaporation of silicon monoxide (SiO). Raman spectroscopy and mapping showed the present method did not degrade graphene, in contrast to the e-beam evaporated SiO2 coating method previously reported. We fabricated graphene field effect transistor devices with four metal electrodes to measure gate voltage dependence of sheet resistance of the graphene, and deposited a top coating of SiO on the graphene channel. The electrical measurements before and after the top-coating revealed that the top coating suppressed chemical shift of the graphene from strong p-dope to nearly undoped. Since SiO is transparent for visible and infrared light, the coating can be available as a protection layer for optical devices of graphene such as photodetectors and electro-optic modulators. Since the SiO top coating is a simple vacuum evaporation, it is much easier than atomic-layer-deposition which requires additional functionalization of graphene, and compatible with industrial use. This research was supported in part by Toyoaki Scholarship Foundation

  19. Um novo Fundef? As idéias de Anísio Teixeira

    Directory of Open Access Journals (Sweden)

    Amaral Nelson Cardoso

    2001-01-01

    Full Text Available O professor Anísio Teixeira, na década de 1960, preocupado com o financiamento da educação, apresentou uma proposta de como definir e implantar um fundo que garantisse recursos permanentes para o ensino primário. Em seus aspectos metodológicos, o Fundo de Manutenção e Desenvolvimento do Ensino Fundamental e de Valorização do Magistério (Fundef, criado pelo Governo, assemelha-se à proposta apresentada por Anísio Teixeira. Existem, entretanto, diferenças importantes e fundamentais, pelo fato do professor Anísio definir o volume total de recursos a partir do estabelecimento do salário dos docentes. Nesse estudo apresentam-se as semelhanças e diferenças entre os dois fundos e realiza-se uma simulação do que se poderia chamar "Um novo Fundef", baseado nas idéias de Anísio Teixeira. Como resultado, obtém-se valores perfeitamente viáveis para serem financiados por uma economia com a dimensão da economia brasileira, assim como ocorreu no estudo apresentado por Anísio Teixeira no livro Educação é um direito.

  20. Integrated nanophotonic hubs based on ZnO-Tb(OH3/SiO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    Lin Yu

    2011-01-01

    Full Text Available Abstract Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH3/SiO2 as well as SnO2-Tb(OH3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.

  1. Intentionality, consciousness, and creating community.

    Science.gov (United States)

    Malinski, Violet M

    2009-01-01

    Intentionality is briefly explored from the perspective of seminal written works on therapeutic touch and recorded conversations with Martha E. Rogers. This overview hints at possible interrelationships among intentionality, consciousness, and creating community, along with conceptual ambiguities, which are explored in detail by Zahourek and Larkin in this column.

  2. We create our own reality

    CERN Multimedia

    2003-01-01

    " Yes, we create our own reality. This is one of the most fundamental tenets of the ancient oriental religions, such as Buddhism. And during the last century, modern particle physics or quantum mechanics has discovered exactly the same thing" (1 page).

  3. Creating Space for Children's Literature

    Science.gov (United States)

    Serafini, Frank

    2011-01-01

    As teachers struggle to balance the needs of their students with the requirements of commercial reading materials, educators need to consider how teachers will create space for children's literature in today's classrooms. In this article, 10 practical recommendations for incorporating children's literature in the reading instructional framework…

  4. Creating an Innovative Learning Organization

    Science.gov (United States)

    Salisbury, Mark

    2010-01-01

    This article describes how to create an innovative learning (iLearning) organization. It begins by discussing the life cycle of knowledge in an organization, followed by a description of the theoretical foundation for iLearning. Next, the article presents an example of iLearning, followed by a description of the distributed nature of work, the…

  5. Creating a New Teaching Profession

    Science.gov (United States)

    Goldhaber, Dan, Ed.; Hannaway, Jane, Ed.

    2009-01-01

    Considering that having a quality teacher is the foremost in-school predictor of students' success, ensuring teacher excellence is vital to the nation's educational system. In "Creating a New Teaching Profession," diverse scholars assess the state of human capital development in the teaching profession today and how to progress.

  6. Natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, J W

    1967-08-01

    This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

  7. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  8. Gas Sensor

    KAUST Repository

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  9. Semiconductor nanocrystals formed in SiO2 by ion implantation

    International Nuclear Information System (INIS)

    Zhu, J.G.; White, C.W.; Budai, J.D.; Withrow, S.P.; Chen, Y.

    1994-11-01

    Nanocrystals of group IV (Si, Ge and SiGe), III-V (GaAs), and II-VI (CdSe) semiconductor materials have been fabricated inside SiO 2 by ion implantation and subsequent thermal annealing. The microstructure of these nanocrystalline semiconductor materials has been studied by transmission electron microscopy (TEM). The nanocrystals form in near-spherical shape with random crystal orientations in amorphous SiO 2 . Extensive studies on the nanocrystal size distributions have been carried out for the Ge nanocrystals by changing the implantation doses and the annealing temperatures. Remarkable roughening of the nanocrystals occurs when the annealing temperature is raised over the melting temperature of the implanted semiconductor material. Strong red photoluminescence peaked around 1.67 eV has been achieved in samples with Si nanocrystals in SiO 2

  10. Positron annihilation spectroscopy of the interface between nanocrystalline Si and SiO2

    International Nuclear Information System (INIS)

    Pi, X.D.; Coleman, P.G.; Harding, R.; Davies, G.; Gwilliam, R.M.; Sealy, B.J.

    2003-01-01

    Positron annihilation spectroscopy has been employed to study changes in the interface region between nanocrystalline Si and SiO 2 , following annealing between 400 deg. C and 900 deg. C in nitrogen or oxygen. With the support of photoluminescence spectroscopy we find that nitrogen and oxygen are trapped in voids at the interface at low temperatures. At temperatures above 700 deg. C both nitrogen and oxygen react with Si nanocrystals, and the resulting volume increase introduces stress in the SiO 2 matrix which is relaxed by the shrinkage of its intrinsic open volume. Oxygen appears to enhance Si diffusion in SiO 2 so that the agglomeration of Si nanocrystals occurs more readily during annealing in oxygen than in nitrogen

  11. Investigation of luminescence properties in SiO2: Tb, Yb upconversion inverse opal

    International Nuclear Information System (INIS)

    Yang Zhengwen; Yan Dong; Song Zhiguo; Zhou Dacheng; Yu Xue; Yang Yong; Yin Zhaoyi; Yan Lei; Wang Rongfei; Wu Hangjun; Qiu Jianbei

    2012-01-01

    The SiO 2 : Tb, Yb inverse opals with photonic band gap at 465 or 543 nm were prepared, and an effect of photonic band gap on upconversion spontaneous emission from Tb 3+ was investigated. The results show that the photonic band gap has a significant influence on the upconversion emission of the SiO 2 : Tb, Yb inverse opals. The upconversion luminescence of the Tb 3+ ions is suppressed in the inverse opal compared with the luminescence of that of the reference sample. - Highlights: ► Upconversion emission from Tb 3+ was observed in the SiO 2 : Tb, Yb inverse opal. ► UC emission of Tb 3+ was modulated by controlling the structure of inverse opal. ► UC emission of Tb 3+ was depressed in the inverse opal.

  12. Self-Ordered Voids Formation in SiO2 Matrix by Ge Outdiffusion

    Directory of Open Access Journals (Sweden)

    B. Pivac

    2018-01-01

    Full Text Available The annealing behavior of very thin SiO2/Ge multilayers deposited on Si substrate by e-gun deposition in high vacuum was explored. It is shown that, after annealing at moderate temperatures (800°C in inert atmosphere, Ge is completely outdiffused from the SiO2 matrix leaving small (about 3 nm spherical voids embedded in the SiO2 matrix. These voids are very well correlated and formed at distances governed by the preexisting multilayer structure (in vertical direction and self-organization (in horizontal direction. The formed films produce intensive photoluminescence (PL with a peak at 500 nm. The explored dynamics of the PL decay show the existence of a very rapid process similar to the one found at Ge/SiO2 defected interface layers.

  13. Ion assisted deposition of SiO2 film from silicon

    Science.gov (United States)

    Pham, Tuan. H.; Dang, Cu. X.

    2005-09-01

    Silicon dioxide, SiO2, is one of the preferred low index materials for optical thin film technology. It is often deposited by electron beam evaporation source with less porosity and scattering, relatively durable and can have a good laser damage threshold. Beside these advantages the deposition of critical optical thin film stacks with silicon dioxide from an E-gun was severely limited by the stability of the evaporation pattern or angular distribution of the material. The even surface of SiO2 granules in crucible will tend to develop into groove and become deeper with the evaporation process. As the results, angular distribution of the evaporation vapor changes in non-predicted manner. This report presents our experiments to apply Ion Assisted Deposition process to evaporate silicon in a molten liquid form. By choosing appropriate process parameters we can get SiO2 film with good and stable property.

  14. Thermal cycling tests on Li4SiO4 and beryllium pebbles

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Norajitra, P.; Weisenburger, A.

    1995-01-01

    The European B.O.T. Demo-relevant solid breeder blanket is based on the use of beds of beryllium and Li 4 SiO 4 pebbles. Particularly dangerous for the pebble integrity are the rapid temperature changes which could occur, for instance, by a sudden blanket power shut-down. A series of thermal cycle tests have been performed for various beds of beryllium and Li 4 SiO 4 pebbles. No breaking was observed in the beryllium pebbles, however the Li 4 SiO 4 pebbles broke by temperature rates of change of about -50 C/sec independently on pebbles size and lithium enrichment. This value is considerably higher than the peak temperature rates of change expected in the blanket. (orig.)

  15. The millimeter-wave spectrum of highly vibrationally excited SiO

    International Nuclear Information System (INIS)

    Mollaaghababa, R.; Gottlieb, C.A.; Vrtilek, J.M.; Thaddeus, P.

    1991-01-01

    The millimeter-wave rotational spectra of SiO in high vibrational states (v = 0-40) in its electronic ground state were measured between 228 and 347 GHz in a laboratory discharge through SiH4 and CO. On ascending the vibrational ladder, populations decline precipitously for the first few levels, with a vibrational temperature of about 1000 K; at v of roughly 3, however, they markedly flatten out, and from there to v of roughly 40 the temperature is of the order of 10,000 K. With the Dunham coefficients determined here, the rotational spectrum of highly vibrationally excited SiO can now be calculated into the far-infrared to accuracies required for radioastronomy. Possible astronomical sources of highly vibrationally excited SiO are certain stellar atmospheres, ultracompact H II regions, very young supernova ejecta, and dense interstellar shocks. 16 refs

  16. Highly efficient transparent Zn2SiO4:Mn2+ phosphor film on quartz glass

    International Nuclear Information System (INIS)

    Seo, K.I.; Park, J.H.; Kim, J.S.; Kim, G.C.; Yoo, J.H.

    2009-01-01

    Highly efficient transparent Zn 2 SiO 4 :Mn 2+ film phosphors on quartz substrates were deposited by the thermal diffusion of sputtered ZnO:Mn film. They show a textured structure with some preferred orientations. Our film phosphor shows, for the best photoluminescence (PL) brightness, a green PL brightness of about 20% of a commercial Zn 2 SiO 4 :Mn 2+ powder phosphor screen. The film shows a high transmittance of more than 10% at the red-color region. The excellence in PL brightness and transmittance can be explained in terms of the textured crystal growth with a continuous gradient of Zn 2 SiO 4 : Mn 2+ crystals.

  17. The hydrophobic and omnidirectional antireflection coating of SiO2 nanospheres with C18-TEOS

    Science.gov (United States)

    Hsu, Cheng-Chih; Lan, Wen-Lin; Chen, Nien-Po; Wu, Chyan-Chyi

    2014-06-01

    This paper demonstrates the antireflection coating of SiO2 nanospheres applied to cover glass by using the optimal spin-coating method. Because of the hydrolysis and condensation reactions between the SiO2 nanosphere antireflection (AR) coating and n-octadecyltriethoxysilane solution (C18-TEOS), the contact angle of the AR coating with hydrophobic treatment is improved approximately 38%, and the moisture-resistance remains unchanged, which preserved similar transmittance for six weeks. Furthermore, the AR coating with hydrophobic treatment exhibits approximately 3% and 7% improvement in the transmittance at normal and oblique incidence, respectively. The hydrophobic and omnidirectional AR coating with nanoscale SiO2 particles can be fabricated using the proposed simple and economical method.

  18. Fabrication of 3D SiO x structures using patterned PMMA sacrificial layer

    Science.gov (United States)

    Li, Zhiqin; Xiang, Quan; Zheng, Mengjie; Bi, Kaixi; Chen, Yiqin; Chen, Keqiu; Duan, Huigao

    2018-02-01

    Three-dimensional (3D) nanofabrication based on electron-beam lithography (EBL) has drawn wide attention for various applications with its high patterning resolution and design flexibility. In this work, we present a bilayer EBL process to obtain 3D freestanding SiO x structures via the release of the bottom sacrificial layer. This new kind of bilayer process enables us to define various 3D freestanding SiO x structures with high resolution and low edge roughness. As a proof of concept for applications, metal-coated freestanding SiO x microplates with an underlying air gap were fabricated to form asymmetric Fabry-Perot resonators, which can be utilized for colorimetric refractive index sensing and thus also have application potential for biochemical detection, anti-counterfeiting and smart active nano-optical devices.

  19. Effect of water layer at the SiO2/graphene interface on pentacene morphology.

    Science.gov (United States)

    Chhikara, Manisha; Pavlica, Egon; Matković, Aleksandar; Gajić, Radoš; Bratina, Gvido

    2014-10-07

    Atomic force microscopy has been used to examine early stages of pentacene growth on exfoliated single-layer graphene transferred to SiO2 substrates. We have observed 2D growth with mean height of 1.5 ± 0.2 nm on as-transferred graphene. Three-dimensional islands of pentacene with an average height of 11 ± 2 nm were observed on graphene that was annealed at 350 °C prior to pentacene growth. Compellingly similar 3D morphology has been observed on graphene transferred onto SiO2 that was treated with hexamethyldisilazane prior to the transfer of graphene. On multilayer graphene we have observed 2D growth, regardless of the treatment of SiO2. We interpret this behavior of pentacene molecules in terms of the influence of the dipolar field that emerges from the water monolayer at the graphene/SiO2 interface on the surface energy of graphene.

  20. Gas phase polymerization of propylene. Reaction kinetics and molecular weight distribution

    NARCIS (Netherlands)

    Meier, G.B.; Weickert, G.; van Swaaij, Willibrordus Petrus Maria

    2001-01-01

    Gas-phase polymerizations have been executed at different temperatures, pressures, and hydrogen concentrations using Me2Si[Ind]2ZrCl2 / methylaluminoxane / SiO2(Pennsylvania Quarts) as a catalyst. The reaction rate curves have been described by a kinetic model, which takes into account the initially

  1. Gas manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Fell, J W

    1915-05-03

    Retorts for the distillation of shale or coal for the production of oil or illuminating-gas are heated by gas from a generator or a gas-holder, and a portion of the gas from the flue leading to the heating-flues is forced by a steam jet through a by-pass and is injected into the bottom of the retorts. If the gas to be admitted to the retort is cold, it is first heated.

  2. Natural Gas

    OpenAIRE

    Bakar, Wan Azelee Wan Abu; Ali, Rusmidah

    2010-01-01

    Natural gas fuel is a green fuel and becoming very demanding because it is environmental safe and clean. Furthermore, this fuel emits lower levels of potentially harmful by-products into the atmosphere. Most of the explored crude natural gas is of sour gas and yet, very viable and cost effective technology is still need to be developed. Above all, methanation technology is considered a future potential treatment method for converting the sour natural gas to sweet natural gas.

  3. DISCOVERY OF SiO BAND EMISSION FROM GALACTIC B[e] SUPERGIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, M. [Astronomický ústav, Akademie věd České republiky, Fričova 298, 251 65 Ondřejov (Czech Republic); Oksala, M. E. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, F-92190, Meudon (France); Cidale, L. S.; Arias, M. L.; Torres, A. F. [Departamento de Espectroscopía Estelar, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata (Argentina); Fernandes, M. Borges, E-mail: michaela.kraus@asu.cas.cz [Observatório Nacional, Rua General José Cristino 77, 20921-400 São Cristovão, Rio de Janeiro (Brazil)

    2015-02-20

    B[e] supergiants (B[e]SGs) are evolved massive stars in a short-lived transition phase. During this phase, these objects eject large amounts of material, which accumulate in a circumstellar disk-like structure. The expelled material is typically dense and cool, providing the cradle for molecule and dust condensation and for a rich, ongoing chemistry. Very little is known about the chemical composition of these disks, beyond the emission from dust and CO revolving around the star on Keplerian orbits. As massive stars preserve an oxygen-rich surface composition throughout their life, other oxygen-based molecules can be expected to form. As SiO is the second most stable oxygen compound, we initiated an observing campaign to search for first-overtone SiO emission bands. We obtained high-resolution near-infrared L-band spectra for a sample of Galactic B[e]SGs with reported CO band emission. We clearly detect emission from the SiO first-overtone bands in CPD-52 9243 and indications for faint emission in HD 62623, HD 327083, and CPD-57 2874. From model fits, we find that in all these stars the SiO bands are rotationally broadened with a velocity lower than observed in the CO band forming regions, suggesting that SiO forms at larger distances from the star. Hence, searching for and analyzing these bands is crucial for studying the structure and kinematics of circumstellar disks, because they trace complementary regions to the CO band formation zone. Moreover, since SiO molecules are the building blocks for silicate dust, their study might provide insight in the early stage of dust formation.

  4. Gas Phase Hydrogenation of Levulinic Acid to gamma-Valerolactone

    NARCIS (Netherlands)

    Bonrath, Werner; Castelijns, Anna Maria Cornelia Francisca; de Vries, Johannes Gerardus; Guit, Rudolf Philippus Maria; Schuetz, Jan; Sereinig, Natascha; Vaessen, Henricus Wilhelmus Leonardus Marie

    The gas phase hydrogenation of levulinic acid to gamma-valerolactone over copper and ruthenium based catalysts in a continuous fixed-bed reactor system was investigated. Among the catalysts a copper oxide based one [50-75 % CuO, 20-25 % SiO2, 1-5 % graphite, 0.1-1 % CuCO3/Cu(OH)(2)] gave

  5. Cavitation in gas-saturated liquids

    NARCIS (Netherlands)

    Rooze, J.

    2012-01-01

    Oscillating gas bubbles can be created in a liquid by exposing it to ultrasound. These gas bubbles implode if the sound pressure is high enough. This process is called cavitation. Interesting phenomena take place during the collapse. The gas and vapour inside the bubble are compressed and reach

  6. A novel fabrication of a high performance SiO(2)-graphene oxide (GO) nanohybrids: Characterization of thermal properties of epoxy nanocomposites filled with SiO(2)-GO nanohybrids.

    Science.gov (United States)

    Haeri, S Z; Ramezanzadeh, B; Asghari, M

    2017-05-01

    In this study it has been aimed to enhance the thermal resistance of epoxy coating through incorporation of SiO 2 -GO nanohybrids. SiO 2 -GO nanohybrids were synthesized through one-step sol-gel route using a mixture of Tetraethylorthosilane (TEOS) and 3-Aminopropyl triethoxysilane (APTES) silanes. The SiO 2 -GO nanohybrids were prepared at various hydrolysis times of 24, 48 and 72h. Then 0.2wt.% of GO and SiO 2 -GO nanohybrids were separately incorporated into the epoxy coating. Results revealed that amino functionalized SiO 2 nanoparticles with particle size around 20-30nm successfully synthesized on the basal plane of GO. Results showed significant improvement of dispersion and interfacial interactions between nanohybrids and epoxy composite arising from covalent bonding between the SiO 2 -GO and the epoxy matrix. It was found that the thermal resistance of SiO 2 -GO nanohybrids and SiO 2 -GO/Epoxy nanocomposite was noticeably higher than GO and epoxy matrix, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Study on the technique for precision measurement of density of SiO_2 foam shells

    International Nuclear Information System (INIS)

    Ma Xiaojun; Gao Dangzhong; Meng Jie

    2013-01-01

    The measuring method based on vertical scanning interference and combined with the relation between refraction index and density of SiO_2 foam shells is introduced, and the relation is analyzed according to formulas of Lorentz-Lorenz and Gladstone-Dale. The experimental result and measuring uncertainty evaluation indicate that the precision measurement of density of low density SiO_2 foam shells can be realized by using the vertical scanning interference technique and combining with Gladstone and Dale analysis method, and the measuring uncertainty is about 5%. (authors)

  8. Ginásio Clube Português (GCP) : measuring customer satisfaction in services industry

    OpenAIRE

    Alves, Guilherme Fernandes Rito

    2015-01-01

    The objective of this thesis is to measure and analyze the customer satisfaction level in Ginásio Clube Português, by understanding the key determinants and consequences of customer satisfaction. After an exponential growth both in revenues and in number of clients between 1998 and 2011, Ginásio Clube Português is losing competitive edge due to the increasing competition in the high-end and low-cost markets as well as due to the effects of the economic downturn. Aiming to en...

  9. A microbiological evaluation of SiO2-coated textiles in hospital interiors

    DEFF Research Database (Denmark)

    Mogensen, Jeppe; Jørgensen, Poul-Erik; Thomsen, Trine Rolighed

    2016-01-01

    . From this perspective, the purpose of this paper is therefore to address focus on alternative passive coatings that without actively killing the bacteria provide a hydrophobic and easy-to-clean textile surface. The paper relates to an in-situ study evaluating the effect and cleaning potential of SiO2...... contact plates through a three-week period. By determining the level of contamination on these surfaces, the study illustrates that the SiO2-coated textile is possible to clean to an acceptable level below the critical limit value of 2,5 Colony Forming Units (CFU) per cm2. In comparison, the traditional...

  10. Bond length contraction in Au nanocrystals formed by ion implantation into thin SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Johannessen, B.; Giraud, V.; Cheung, A.; Glover, C.J.; Azevedo, G. de M; Foran, G.J.; Ridgway, M.C.

    2004-01-01

    Au nanocrystals (NCs) fabricated by ion implantation into thin SiO 2 and annealing were investigated by means of extended x-ray absorption fine structure (EXAFS) spectroscopy and transmission electron microscopy. A bond length contraction was observed and can be explained by surface tension effects in a simple liquid-drop model. Such results are consistent with previous reports on nonembedded NCs implying a negligible influence of the SiO 2 matrix. Cumulant analysis of the EXAFS data suggests surface reconstruction or relaxation involving a further shortened bond length. A deviation from the octahedral closed shell structure is apparent for NCs of size 25 A

  11. Luminescence and origin of lead-related centers in single crystalline films of Y2SiO5 and Lu2SiO5

    International Nuclear Information System (INIS)

    Babin, V.; Gorbenko, V.; Krasnikov, A.; Mihokova, E.; Nikl, M.; Zazubovich, S.; Zorenko, Yu.

    2013-01-01

    In the temperature range 4.2–350 K, the steady-state and time-resolved emission and excitation spectra and luminescence decay kinetics are studied for the undoped Y 2 SiO 5 and Lu 2 SiO 5 single crystalline films grown by liquid phase epitaxy method from the PbO-based flux and, owing to that, containing lead ions substituting for Y 3+ or Lu 3+ ions. Luminescence characteristics of Pb-related centers of different types are identified. On the basis of the results obtained, we suggest that the ultraviolet emission of Pb-related centers arises from the Pb 2+ ions substituting for Y 3+ or Lu 3+ ions in the Y1 and Lu1 lattice sites of the X 2 structure. Possible hypotheses on the origin of the intense complex lead-related blue emission are discussed. We propose phenomenological models describing the excited-state dynamics of the studied luminescence centers. We also determine characteristic parameters of the corresponding relaxed excited states, in particular, the energy separations between the excited states and the rates of the radiative and non-radiative transitions from these states. -- Highlights: •Emission of lead centers in Y 2 SiO 5 and Lu 2 SiO 5 single crystalline films is studied. •The ultraviolet emission arises from Pb 2+ ions located in Y1 or Lu1 lattice sites. •Possible hypotheses on the origin of the blue emission are proposed and discussed. •The relaxed excited states parameters of various Pb-related centers are determined

  12. Leadership Networking Connect, Collaborate, Create

    CERN Document Server

    (CCL), Center for Creative Leadership; Baldwin, David

    2011-01-01

    Networking is essential to effective leadership in today's organizations. Leaders who are skilled networkers have access to people, information, and resources to help solve problems and create opportunities. Leaders who neglect their networks are missing out on a critical component of their role as leaders. This book will help leaders take a new view of networking and provide insight into how to enhance their networks and become effective at leadership networking.

  13. Synthesis of Hollow Nanotubes of Zn2SiO4 or SiO2: Mechanistic Understanding and Uranium Adsorption Behavior.

    Science.gov (United States)

    Tripathi, Shalini; Bose, Roopa; Roy, Ahin; Nair, Sajitha; Ravishankar, N

    2015-12-09

    We report a facile synthesis of Zn2SiO4 nanotubes using a two-step process consisting of a wet-chemical synthesis of core-shell ZnO@SiO2 nanorods followed by thermal annealing. While annealing in air leads to the formation of hollow Zn2SiO4, annealing under reducing atmosphere leads to the formation of SiO2 nanotubes. We rationalize the formation of the silicate phase at temperatures much lower than the temperatures reported in the literature based on the porous nature of the silica shell on the ZnO nanorods. We present results from in situ transmission electron microscopy experiments to clearly show void nucleation at the interface between ZnO and the silica shell and the growth of the silicate phase by the Kirkendall effect. The porous nature of the silica shell is also responsible for the etching of the ZnO leading to the formation of silica nanotubes under reducing conditions. Both the hollow silica and silicate nanotubes exhibit good uranium sorption at different ranges of pH making them possible candidates for nuclear waste management.

  14. Pricing of natural gas in Kazakhstan

    International Nuclear Information System (INIS)

    Zhapargaliev, I.K.

    1996-01-01

    Two state companies are in charge of natural gas supply in Kazakhstan. They buy, transport and sell natural gas and have monopolized the industry and provoked increase of gas prices. Ministry of Oil and gas Industry proposed demonopolization. The restructuring that took place caused new distribution of tasks in the gas industry. A more competitive environment was created leading to normalization of the natural gas prices. All economic subjects were granted the right to acquire gas regardless the type of ownership. Measures implemented for reorganization of gas companies contributed to the reduction of gas transport costs and prices by 50% and to decrease of gas prices in the southern regions by 50%. Despite these measures gas prices for household sector are still unchanged and are below the import prices, the main reason being the low average household income

  15. Gas supply device

    International Nuclear Information System (INIS)

    Yamamoto, Tokihiro.

    1986-01-01

    Purpose: When injecting gas during plasma discharge, to prevent erronous operation of the piezoelectric valves due to vibrations and to inject gas into the vacuum vessel by accurately controlling gas flow. Constitution: The piezoelectric valve designed to control the flow of gas when charging vacuum vessels is installed between the vacuum vessel and the gas cylinder and a pulse voltage generator to control the valve (open/close) and the reverse voltage generator to apply a reverse current to the valve element are also provided. When a voltage is applied to the piezoelectric element, the piezoelectric element bends. However, when the polarity is changed, the direction of the bend is also reversed. The seat portion is pressed in proportion to the degree of bending. When gas is injected while plasma is being discharged, the gap created, due to vibrations, between the piezoelectric element and the sealing material is prevented by the application of a reverse current. This allows precise control of the gas injection volume as well as the injection interval. This assures maintenance of precise test conditions when testing thermonuclear devices. (Horiuchi, T.)

  16. Enhancement of photocatalytic degradation of furfural and acetophenone in water media using nano-TiO2-SiO2 deposited on cementitious materials.

    Science.gov (United States)

    Soltan, Sahar; Jafari, Hoda; Afshar, Shahrara; Zabihi, Omid

    2016-10-01

    In the present study, silicon dioxide (SiO 2 ) nanoparticles were loaded to titanium dioxide (TiO 2 ) nano-particles by sol-gel method to make a high porosity photocatalyst nano-hybrid. These photocatalysts were synthesized using titanium tetrachloride and tetraethyl orthosilicate as titanium and silicon sources, respectively, and characterized by X-ray powder diffraction (XRD) and scanning electron microscope methods. Subsequently, the optimizations of the component and operation conditions were investigated. Then, nano-sized TiO 2 and TiO 2 -SiO 2 were supported on concrete bricks by the dip coating process. The photocatalytic activity of nano photocatalysts under UV irradiation was examined by studying the decomposition of aqueous solutions of furfural and acetophenone (10 mg/L) as model of organic pollutants to CO 2 and H 2 O at room temperature. A decrease in the concentration of these pollutants was assayed by using UV-visible absorption, gas chromatography technique, and chemical oxygen demand. The removal of these pollutants from water using the concrete-supported photocatalysts under UV irradiation was performed with a greater efficiency, which does not require an additional separation stage to recover the catalyst. Therefore, it would be applicable to use in industrial wastewater treatment at room temperature and atmospheric pressure within the optimized pH range.

  17. Ethanol-to-Butadiene Conversion over SiO2-MgO Catalysts: Synthesis-Structure-Performance Relationships

    NARCIS (Netherlands)

    Angelici, C.

    2015-01-01

    The work presented in this PhD Thesis provides new insights into the underlying reasons that make SiO2-MgO materials excellent catalysts for the ethanol-to-butadiene Lebedev process. In particular, the preparation technique of choice affects the structural properties of the resulting SiO2-MgO

  18. Sensitizing effects of ZnO quantum dots on red-emitting Pr3+-doped SiO2 phosphor

    CSIR Research Space (South Africa)

    Mbule, PS

    2012-05-01

    Full Text Available In this study, red cathodoluminescence (CL) ( emission=614 nm) was observed from Pr3+ ions in a glassy (amorphous) SiO2 host. This emission was enhanced considerably when ZnO quantum dots (QDs) were incorporated in the SiO2:Pr3+ suggesting...

  19. Preparation of Raspberry-like Superhydrophobic SiO2 Particles by Sol-gel Method and Its Potential Applications

    Directory of Open Access Journals (Sweden)

    Xu Gui-Long

    2011-12-01

    Full Text Available Raspberry‐like SiO2 particles with a nano‐micro‐binary structure were prepared by a simple sol‐gel method using tetraethoxysilane (TEOS and methyltriethoxysilane (MTES as precursors. The chemical components and morphology of the SiO2 particles were characterized by Fourier transform infrared spectroscopy (FT‐IR and a Transmission electron microscope (TEM. The surface topography and wetting behaviour of the raspberry‐like SiO2 surface were observed with a Scanning electron microscope (SEM and studied by the water/oil contact angle (CA, respectively. The thermal stability of the prepared SiO2 particles was characterized by TGA analysis. The results show that the highly dispersed SiO2 particles initially prepared by the sol‐gel method turn into raspberry‐like particles with during the aging process. The raspberry‐like SiO2 particles show superhydrophobicity and superoleophilicity across a wide range of pH values. The SiO2 particles were thermally stable up to 475°C, while above this temperature the hydrophobicity decreases and finally becomes superhydrophobic when the temperature reaches 600°C. The raspberry‐like SiO2 particles which were prepared have potential applications in the fields of superhydrophobic surfaces, water‐oil separation, anti‐corrosion and fluid transportation.

  20. Biomedical bandpass filter for fluorescence microscopy imaging based on TiO2/SiO2 and TiO2/MgF2 dielectric multilayers

    International Nuclear Information System (INIS)

    Butt, M A; Fomchenkov, S A; Verma, P; Khonina, S N; Ullah, A

    2016-01-01

    We report a design for creating a multilayer dielectric optical filters based on TiO 2 and SiO 2 /MgF 2 alternating layers. We have selected Titanium dioxide (TiO 2 ) for high refractive index (2.5), Silicon dioxide (SiO 2 ) and Magnesium fluoride (MgF 2 ) as a low refractive index layer (1.45 and 1.37) respectively. Miniaturized visible spectrometers are useful for quick and mobile characterization of biological samples. Such devices can be fabricated by using Fabry-Perot (FP) filters consisting of two highly reflecting mirrors with a central cavity in between. Distributed Bragg Reflectors (DBRs) consisting of alternating high and low refractive index material pairs are the most commonly used mirrors in FP filters, due to their high reflectivity. However, DBRs have high reflectivity for a selected range of wavelengths known as the stopband of the DBR. This range is usually much smaller than the sensitivity range of the spectrometer range. Therefore a bandpass filters are required to restrict wavelength outside the stopband of the FP DBRs. The proposed filter shows a high quality with average transmission of 97.4% within the passbands and the transmission outside the passband is around 4%. Special attention has been given to keep the thickness of the filters within the economic limits. It can be suggested that these filters are exceptional choice for florescence imaging and Endoscope narrow band imaging. (paper)

  1. Creating a digital medical illustration.

    Science.gov (United States)

    Culley, Joanna

    2016-01-01

    This paper covers the steps required to complete a medical illustration in a digital format using Adobe Illustrator and Photoshop. The project example is the surgical procedure for the release of the glenohumeral joint for the condition known as 'frozen shoulder'. The purpose is to demonstrate one method which an artist can use within digital media to create a colour illustration such as the release of the glenohumeral joint. Included is a general overview as how to deal with the administration of a medical illustration commission through the experience of a professional freelance artist.

  2. Natural gas and electricity convergence

    International Nuclear Information System (INIS)

    Calger, C.

    1998-01-01

    Convergence between the gas and electricity industries was described as a means for creating an increasingly more efficient energy market where prices and fundamental relationships exist between gas and electricity. Convergence creates new opportunities for producers and consumers. Convergence will likely lead to the disaggregation of the electricity and gas industry into segments such as: (1) power generation and production, (2) transmission wires and pipelines, (3) wholesale merchants, (4) distribution wires and pipelines, and (5) retail marketing, services and administration. The de-integration of integrated utilities has already begun in the U.S. energy markets and retail open access is accelerating. This retail competition will create very demanding customers and the changing risk profile will create new issues for stakeholders. The pace of reform for the telecommunications, airlines, natural gas and electricity industries was graphically illustrated to serve as an example of what to expect. The different paths that the industry might take to deregulation (aggressively embrace reform, or defensively blocking it), and the likely consequences of each reaction were also described. A map indicating where U.S. electric and natural gas utility merger and acquisition activities have taken place between 1994-1997, was included. Another map showing the physical asset positions of the Enron grid, one of the largest independent oil and gas companies in the U.S., with increasing international operations, including an electric power transmission and distribution arm, was also provided as an illustration of a fully integrated energy market company of the future. 9 figs

  3. Thickness and composition of ultrathin SiO2 layers on Si

    NARCIS (Netherlands)

    van der Marel, C; Verheijen, M.A.; Tamminga, Y; Pijnenburg, RHW; Tombros, N; Cubaynes, F

    2004-01-01

    Ultrathin SiO2 layers are of importance for the semiconductor industry. One of the techniques that can be used to determine the chemical composition and thickness of this type of layers is x-ray photoelectron spectroscopy (XPS). As shown by Seah and Spencer [Surf. Interface Anal. 33, 640 (2002)], it

  4. Enhanced Photocatalytic Activity of ZrO2-SiO2 Nanoparticles by Platinum Doping

    Directory of Open Access Journals (Sweden)

    Mohammad W. Kadi

    2013-01-01

    Full Text Available ZrO2-SiO2 mixed oxides were prepared via the sol-gel method. Photo-assisted deposition was utilized for doping the prepared mixed oxide with 0.1, 0.2, 0.3, and 0.4 wt% of Pt. XRD spectra showed that doping did not result in the incorporation of Pt within the crystal structure of the material. UV-reflectance spectrometry showed that the band gap of ZrO2-SiO2 decreased from 3.04 eV to 2.48 eV with 0.4 wt% Pt doping. The results show a specific surface area increase of 20%. Enhanced photocatalysis of Pt/ZrO2-SiO2 was successfully tested on photo degradation of cyanide under illumination of visible light. 100% conversion was achieved within 20 min with 0.3 wt% of Pt doped ZrO2-SiO2.

  5. PAC study in the HfO2-SiO2 system

    International Nuclear Information System (INIS)

    Chain, C.Y.; Damonte, L.C.; Ferrari, S.; Munoz, E.; Torres, C. Rodriguez; Pasquevich, A.F.

    2010-01-01

    A high-k HfO 2 /SiO 2 gate stack is taking the place of SiO 2 as a gate dielectric in field effect transistors. This fact makes the study of the solid-state reaction between these oxides very important. Nanostructure characterization of a high-energy ball milled and post-annealed equimolar HfO 2 and amorphous SiO 2 powder mixture has been carried out by perturbed angular correlations (PAC) technique. The study was complemented with X-ray diffraction and positron annihilation lifetime spectroscopy (PALS). The experimental results revealed that the ball milling of equimolar mixtures increases the defects concentration in hafnium oxide. No solid-state reaction occurred even after 8 h of milling. The formation of HfSiO 4 (hafnon) was observed in the milled blends annealed at high temperatures.The PAC results of the milled samples are compared with those obtained for pure m-ZrO 2 subjected to high-energy ball milling and with reported microstructure data for the system ZrO 2 -SiO 2 .

  6. Defect layer in SiO2-Sic interface proved by a slow positron beam

    International Nuclear Information System (INIS)

    Maekawa, M.; Kawasuso, A.; Yoshikawa, M.; Miyashita, A.; Suzuki, R.; Ohdaira, T.

    2006-01-01

    The structure of the SiO 2 -4ph-SiC interface layer produced by dry oxidation has been studied by positron annihilation spectroscopy using slow positron beams. From Doppler broadening measurements, the interface layer was clearly distinguished from the SiO 2 and SiC layers and was observed to be defective. At the interface layer, a single long positron lifetime of 451 ps, which is close to the second lifetime in the SiO 2 layer, was obtained, thus suggesting that the structure of the interface layer resembles an amorphous SiO 2 network. A comparison was made between the obtained electron momentum distribution at the interface layer and the theoretical calculation. It was found that positrons annihilate with oxygen valence electrons. By annealing after the oxidation, the annihilation probability of the positrons with oxygen valence electrons and the number of interface traps decreased in the same temperature range, thus suggesting a correlation between interface traps and positron annihilation sites

  7. SiO maser emission as a density tracer of circumstellar envelopes

    Science.gov (United States)

    Stroh, Michael; Pihlstrom, Ylva; Sjouwerman, Lorant

    2018-06-01

    The circumstellar envelopes (CSEs) of evolved stars offer a method to construct a sample of point-masses along the full Galactic plane, which can be used to test models of the gravitational potential. In the CSEs of red giants, SiO maser emission is frequently observed at 43 and 86 GHz, providing line-of-sight velocities. The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by observing 43 GHz SiO at the Very Large Array and 86 GHz SiO at the Atacama Large Millimeter/submillimeter Array, with an expected final sample of about 20,000 line-of-sight velocities and positions. We observed the 43 GHz and 86 GHz transitions near-simultaneously in a subsample of the sources using the Australia Telescope Compact Array and found that on average the 43 GHz v=1 line is 1.3 times stronger than the 86 GHz v=1 line. The presence of a detectable 43 GHz v=3 line alters the statistics, consistent with the SiO masers displaying 43 GHz v=3 emission arising in a denser regime in the circumstellar shell compared to those without. Comparing our results with radiative models implies that the 43 GHz v=3 line is a tracer of density variations caused by stellar pulsations. We will discuss these results in the context of the BAaDE project.

  8. Hazards of TiO2 and amorphous SiO2 nanoparticles

    NARCIS (Netherlands)

    Reijnders, L.; Kahn, H.A.; Arif, I.A.

    2012-01-01

    TiO2 and amorphous SiO2 nanoparticles have been described as ‘safe’, ‘non-toxic’ and ‘environment friendly’ in scientific literature. However, though toxicity data are far from complete, there is evidence that these nanoparticles are hazardous. TiO2 nanoparticles have been found hazardous to humans

  9. 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...

  10. Preparation of TiO2-SiO2 composite photocatalysts for environmental applications

    Czech Academy of Sciences Publication Activity Database

    Paušová, Š.; Krýsa, J.; Jirkovský, Jaromír; Prevot, V.; Mailhot, G.

    2014-01-01

    Roč. 89, č. 8 (2014), s. 1129-1135 ISSN 0268-2575 Institutional support: RVO:61388955 Keywords : photocatalysis * TiO2/SiO2 * composite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.349, year: 2014

  11. Catalytic combustion of trichloroethylene over TiO2-SiO2 supported catalysts

    NARCIS (Netherlands)

    Kulazynski, M.; van Ommen, J.G.; Trawczynski, J.; Walendziewski, J.

    2002-01-01

    Combustion of trichloroethylene (TCE) on Cr2O3, V2O5, Pt or Pd catalysts supported on TiO2-SiO2 as a carrier has been investigated. It was found that oxide catalysts are very active but their activity quickly diminishes due to loss of the active component, especially at higher reaction temperatures

  12. Electrocatalytic oxidation of alcohols on single gold particles in highly ordered SiO2 cavities

    International Nuclear Information System (INIS)

    Li, Na; Zhou, Qun; Tian, Shu; Zhao, Hong; Li, Xiaowei; Adkins, Jason; Gu, Zhuomin; Zhao, Lili; Zheng, Junwei

    2013-01-01

    In the present work, we report a new and simple approach for preparing a highly ordered Au (1 1 1) nanoparticle (NP) array in SiO 2 cavities on indium-doped tin oxide (ITO) electrodes. We fabricated a SiO 2 cavity array on the surface of an ITO electrode using highly ordered self-assembly of polystyrene spheres as a template. Gold NPs were electrodeposited at the bottom of the SiO 2 cavities, and single gold NPs dominated with (1 1 1) facets were generated in each cavity by annealing the electrode at a high temperature. Such (1 1 1) facets were the predominate trait of the single gold particle which exhibited considerable electrocatalytic activity toward oxidation of methanol, ethanol, and glycerol. This has been attributed to the formation of incipient hydrous oxides at unusually low potential on the specific (1 1 1) facet of the gold particles. Moreover, each cavity of the SiO 2 possibly behaves as an independent electrochemical cell in which the methanol molecules are trapped; this produces an environment advantageous to catalyzing electrooxidation. The oxidation of methanol on the electrodes is a mixed control mechanism (both by diffusion and electrode kinetics). This strategy both provided an approach to study electrochemical reactions on a single particle in a microenvironment and may supply a way to construct alcohols sensors

  13. FeCl3.nano SiO2: An Efficient Heterogeneous Nano Catalyst for the ...

    African Journals Online (AJOL)

    NICO

    2012-05-28

    May 28, 2012 ... low cost, ease of preparation, and catalyst recycling.3,4 Among various solid .... FeCl3-SiO2 (np) to produce 1,8-dioxo-octahydro-xanthenes. RESEARCH ..... 38 G. Song, B. Wang, H. Luo and L. Yang, Catal. Commun., 2007, 8 ...

  14. Enhanced field emission properties of carbon nanotube bundles confined in SiO2 pits

    Science.gov (United States)

    Lim, Yu Dian; Grapov, Dmitry; Hu, Liangxing; Kong, Qinyu; Tay, Beng Kang; Labunov, Vladimir; Miao, Jianmin; Coquet, Philippe; Aditya, Sheel

    2018-02-01

    It has been widely reported that carbon nanotubes (CNTs) exhibit superior field emission (FE) properties due to their high aspect ratios and unique structural properties. Among the various types of CNTs, random growth CNTs exhibit promising FE properties due to their reduced inter-tube screening effect. However, growing random growth CNTs on individual catalyst islands often results in spread out CNT bundles, which reduces overall field enhancement. In this study, significant improvement in FE properties in CNT bundles is demonstrated by confining them in microfabricated SiO2 pits. Growing CNT bundles in narrow (0.5 μm diameter and 2 μm height) SiO2 pits achieves FE current density of 1-1.4 A cm-2, which is much higher than for freestanding CNT bundles (76.9 mA cm-2). From the Fowler Nordheim plots, confined CNT bundles show a higher field enhancement factor. This improvement can be attributed to the reduced bundle diameter by SiO2 pit confinement, which yields bundles with higher aspect ratios. Combining the obtained outcomes, it can be conclusively summarized that confining CNTs in SiO2 pits yields higher FE current density due to the higher field enhancement of confined CNTs.

  15. Irradiation-induced hardening/softening in SiO2 studied with instrumented indentation

    International Nuclear Information System (INIS)

    Nakano, Shinsuke; Muto, Shunsuke; Tanabe, Tetsuo

    2005-01-01

    To understand the plastic deformation mechanism of SiO 2 polytypes, we measured the mechanical parameters of He + -irradiated crystalline SiO 2 (α-quartz, c-SiO 2 ) and vitreous SiO 2 (silica glass, v-SiO 2 ) as functions of the irradiation dose, by using the instrumented indentation method combined with a finite-element analysis. We extracted the effects of local rotation and bending of the SiO 4 framework (the degree of local structural freedom), which play key roles in the plastic deformation, and expressed the hardness change with a simple formula. For v-SiO 2 , the changes in the density and the number of broken bonds correlated well with the change in the degree of freedom. In contrast, for c-SiO 2 the present formulation was insufficient to fully express the hardness change in the structural disordering regime. The structure change by irradiation peculiar to this material is discussed, based on the theoretical formulation

  16. SiO2 Glass Density to Lower-Mantle Pressures

    DEFF Research Database (Denmark)

    Petitgirard, Sylvain; Malfait, Wim J.; Journaux, Baptiste

    2017-01-01

    and present Earth. SiO2 is the main constituent of Earth's mantle and is the reference model system for the behavior of silicate melts at high pressure. Here, we apply our recently developed x-ray absorption technique to the density of SiO2 glass up to 110 GPa, doubling the pressure range...... for such measurements. Our density data validate recent molecular dynamics simulations and are in good agreement with previous experimental studies conducted at lower pressure. Silica glass rapidly densifies up to 40 GPa, but the density trend then flattens to become asymptotic to the density of SiO2 minerals above 60...... GPa. The density data present two discontinuities at similar to 17 and similar to 60 GPa that can be related to a silicon coordination increase from 4 to a mixed 5/6 coordination and from 5/6 to sixfold, respectively. SiO2 glass becomes denser than MgSiO3 glass at similar to 40 GPa, and its density...

  17. Theory of Al2O3 incorporation in SiO2

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper

    2002-01-01

    Different possible forms of Al2O3 units in a SiO2 network are studied theoretically within the framework of density-functional theory. Total-energy differences between the various configurations are obtained, and simple thermodynamical arguments are used to provide an estimate of their relative...

  18. Crystallization kinetics of BaO-Al2O3-SiO2 glasses

    Science.gov (United States)

    Bansal, Narottam P.; Hyatt, Mark J.

    1989-01-01

    Barium aluminosilicate glasses are being investigated as matrix materials in high-temperature ceramic composites for structural applications. Kinetics of crystallization of two refractory glass compositions in the barium aluminosilicate system were studied by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). From variable heating rate DTA, the crystallization activation energies for glass compositions (wt percent) 10BaO-38Al2O3-51SiO2-1MoO3 (glass A) and 39BaO-25Al2O3-35SiO2-1MoO3 (glass B) were determined to be 553 and 558 kJ/mol, respectively. On thermal treatment, the crystalline phases in glasses A and B were identified as mullite (3Al2O3-2SiO2) and hexacelsian (BaO-Al2O3-2SiO2), respectively. Hexacelsian is a high-temperature polymorph which is metastable below 1590 C. It undergoes structural transformation into the orthorhombic form at approximately 300 C accompanied by a large volume change which is undesirable for structural applications. A process needs to be developed where stable monoclinic celsian, rather than hexacelsian, precipitates out as the crystal phase in glass B.

  19. Selective SiO2 etching in three dimensional structures using parylene-C as mask

    NARCIS (Netherlands)

    Veltkamp, Henk-Willem; Zhao, Yiyuan; de Boer, Meint J.; Wiegerink, Remco J.; Lötters, Joost Conrad

    2017-01-01

    This abstract describes an application of an easy and straightforward method for selective SiO2 etching in three dimensional structures, which is developed by our group. The application in this abstract is the protection of the buried-oxide (BOX) layer of a silicon-on-insulator (SOI) wafer against

  20. CoFe2O4-SiO2 Composites: Preparation and Magnetodielectric Properties

    Directory of Open Access Journals (Sweden)

    T. Ramesh

    2016-01-01

    Full Text Available Cobalt ferrite (CoFe2O4 and silica (SiO2 nanopowders have been prepared by the microwave hydrothermal (M-H method using metal nitrates as precursors of CoFe2O4 and tetraethyl orthosilicate as a precursor of SiO2. The synthesized powders were characterized by XRD and FESEM. The (100-x (CoFe2O4 + xSiO2 (where x = 0%, 10%, 20%, and 30% composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD, Fourier transformation infrared (FTIR spectra, and scanning electron microscopy (SEM, respectively. The effect of SiO2 content on the magnetic and electrical properties of CoFe2O4/SiO2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.

  1. Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO2.

    Science.gov (United States)

    Gasvoda, Ryan J; van de Steeg, Alex W; Bhowmick, Ranadeep; Hudson, Eric A; Agarwal, Sumit

    2017-09-13

    Surface phenomena during atomic layer etching (ALE) of SiO 2 were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF x ) film deposition and Ar plasma activation of the CF x film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF x deposition half-cycle from a C 4 F 8 /Ar plasma show that an atomically thin mixing layer is formed between the deposited CF x layer and the underlying SiO 2 film. Etching during the Ar plasma cycle is activated by Ar + bombardment of the CF x layer, which results in the simultaneous removal of surface CF x and the underlying SiO 2 film. The interfacial mixing layer in ALE is atomically thin due to the low ion energy during CF x deposition, which combined with an ultrathin CF x layer ensures an etch rate of a few monolayers per cycle. In situ ellipsometry shows that for a ∼4 Å thick CF x film, ∼3-4 Å of SiO 2 was etched per cycle. However, during the Ar plasma half-cycle, etching proceeds beyond complete removal of the surface CF x layer as F-containing radicals are slowly released into the plasma from the reactor walls. Buildup of CF x on reactor walls leads to a gradual increase in the etch per cycle.

  2. Creating Cross-disciplinary Courses.

    Science.gov (United States)

    Reynolds, Elaine R

    2012-01-01

    Because of its focus on the biological underpinnings of action and behavior, neuroscience intersects with many fields of human endeavor. Some of these cross-disciplinary intersections have been long standing, while others, such as neurotheology or neuroeconomics, are more recently formed fields. Many undergraduate institutions have sought to include cross-disciplinary courses in their curriculum because this style of pedagogy is often seen as applicable to real world problems. However, it can be difficult for faculty with specialized training within their discipline to expand beyond their own fields to offer cross-disciplinary courses. I have been creating a series of multi- or cross-disciplinary courses and have found some strategies that have helped me successfully teach these classes. I will discuss general strategies and tools in developing these types of courses including: 1) creating mixed experience classrooms of students and contributing faculty 2) finding the right tools that will allow you to teach to a mixed population without prerequisites 3) examining the topic using multiple disciplinary perspectives 4) feeding off student experience and interest 5) assessing the impact of these courses on student outcomes and your neuroscience program. This last tool in particular is important in establishing the validity of this type of teaching for neuroscience students and the general student population.

  3. Creating your own leadership brand.

    Science.gov (United States)

    Kerfoot, Karlene

    2002-01-01

    Building equity in a brand happens through many encounters. The initial attraction must be followed by the meeting of expectations. This creates a loyalty that is part of an emotional connection to that brand. This is the same process people go through when they first meet a leader and decide if this is a person they want to buy into. People will examine your style, your competence, and your standards. If you fail on any of these fronts, your ability to lead will be severely compromised. People expect more of leaders now, because they know and recognize good leaders. And, predictably, people are now more cynical of leaders because of the well-publicized excess of a few leaders who advanced their own causes at the expense of their people and their financial future. This will turn out to be a good thing, because it will create a higher standard of leadership that all must aspire to achieve. When the bar is raised for us, our standards of performance are also raised.

  4. Creating nanoscale emulsions using condensation.

    Science.gov (United States)

    Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

    2017-11-08

    Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.

  5. OPPOSITIONS CREATING HOMOUR IN JOKES

    Directory of Open Access Journals (Sweden)

    Umral Deveci

    2016-12-01

    Full Text Available Human beings, who perceive the reality of death however who do not know when it will happen, begin their life with this deficiency. Therefore, throughout their lives, they struggle to consummate and make up for the things that they perceive as deficiency or shortcomings through different ways. Humor is one of these means. The fact that deficiencies are eliminated results in superiority and relaxation. The sense of humor and relaxation simultaneously provide laughter. When theories of humor such as superiority, incongruous and relief are taken into consideration, it seems that these theories are related and support each other. Each text is whole with its form and content, which should be evaluated as a whole as much as possible. Hence this study dwells on shortcomings in jokes and in the lights of these shortcomings and theories of humor, it is intended tomake humor in stories, in terms of structural and semantic context, more concrete. Five stories/jokes randomly selected through samples are analyzed in this article. There are two basic types of opposition. The firstone is opposition that creates situation, the second one is thatcreates laughter. The first opposition depicts the shortcomings of knowledge, skill, patience arrogance and jealousyand prepares the second opposition. The opposition that creates laughter make up for shortcomings through cause and effect relationship and laughter comes out.

  6. Creating an effective poster presentation.

    Science.gov (United States)

    Taggart, H M; Arslanian, C

    2000-01-01

    One way to build knowledge in nursing is to share research findings or clinical program outcomes. The dissemination of these findings is often a difficult final step in a project that has taken months or years to complete. One method of sharing findings in a relaxed and informal setting is a poster presentation. This method is an effective form for presenting findings using an interactive approach. The milieu of a poster presentation enables the presenters to interact and dialogue with colleagues. Guidelines for size and format require that the poster is clear and informative. Application of design helps to create visually appealing posters. This article summarizes elements of designing and conducting a poster presentation.

  7. Supporting SMEs in creating jobs

    Directory of Open Access Journals (Sweden)

    Daniela PASNICU

    2018-03-01

    Full Text Available SMEs are the most dynamic sector of the economy, representing a key factor in employment growth. Although SMEs have been severely affected by the economic crisis from 2008, they continue to be a more and more important source of generating jobs, regardless of size class. Given the differentiated contribution of SMEs to job creation as a result of their heterogeneity, the article analyses the dynamics of staff in enterprises by size classes and activities of the national economy. The statistical analysis is followed by a SWOT analysis of policies and tools to support SMEs in creating jobs both with direct action - management, recruitment, training and indirectly action by addressing general business issues. Measures that support the economic growth of SMEs through internationalization, innovation and improved access to finance foster competitiveness and, implicitly, the creation of new jobs.

  8. Creating breakthroughs at 3M.

    Science.gov (United States)

    von Hippel, E; Thomke, S; Sonnack, M

    1999-01-01

    Most senior managers want their product development teams to create break-throughs--new products that will allow their companies to grow rapidly and maintain high margins. But more often they get incremental improvements to existing products. That's partly because companies must compete in the short term. Searching for breakthroughs is expensive and time consuming; line extensions can help the bottom line immediately. In addition, developers simply don't know how to achieve breakthroughs, and there is usually no system in place to guide them. By the mid-1990s, the lack of such a system was a problem even for an innovative company like 3M. Then a project team in 3M's Medical-Surgical Markets Division became acquainted with a method for developing breakthrough products: the lead user process. The process is based on the fact that many commercially important products are initially thought of and even prototyped by "lead users"--companies, organizations, or individuals that are well ahead of market trends. Their needs are so far beyond those of the average user that lead users create innovations on their own that may later contribute to commercially attractive breakthroughs. The lead user process transforms the job of inventing breakthroughs into a systematic task of identifying lead users and learning from them. The authors explain the process and how the 3M project team successfully navigated through it. In the end, the team proposed three major new product lines and a change in the division's strategy that has led to the development of breakthrough products. And now several more divisions are using the process to break away from incrementalism.

  9. Silicon surface damage caused by reactive ion etching in fluorocarbon gas mixtures containing hydrogen

    International Nuclear Information System (INIS)

    Norstroem, H.; Blom, H.; Ostling, M.; Nylandsted Larsen, A.; Keinonen, J.; Berg, S.

    1991-01-01

    For selective etching of SiO 2 on silicon, gases or gas mixtures containing hydrogen are often used. Hydrogen from the glow discharge promotes the formation of a thin film polymer layer responsible for the selectivity of the etching process. The reactive ion etch (RIE) process is known to create damage in the silicon substrate. The influence of hydrogen on the damage and deactivation of dopants is investigated in the present work. The distribution of hydrogen in silicon, after different etching and annealing conditions have been studied. The influence of the RIE process on the charge carrier concentration in silicon has been investigated. Various analytical techniques like contact resistivity measurements, four point probe measurements, and Hall measurements have been used to determine the influence of the RIE process on the electrical properties of processed silicon wafers. The hydrogen profile in as-etched and post annealed wafers was determined by the 1 H( 15 N,αγ) 12 C nuclear reaction. The depth of the deactivated surface layer is discussed in terms of the impinging hydrogen ion energy, i.e., the possibility of H + ions to pick up an energy equal to the peak-to-peak voltage of the rf signal

  10. Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO2 fiber

    International Nuclear Information System (INIS)

    Katsumata, Toru; Morita, Kentaro; Komuro, Shuji; Aizawa, Hiroaki

    2014-01-01

    Visible light thermal radiation from SiO 2 glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO 2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO 2 fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO 2 fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO 2 fibers are smaller than those from SiO 2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO 2 are potentially applicable for the fiber-optic thermometry above 900 K

  11. Luminescence properties of Ca2 Ga2 SiO7 :RE phosphors for UV white-light-emitting diodes.

    Science.gov (United States)

    Jiao, Mengmeng; Lv, Wenzhen; Lü, Wei; Zhao, Qi; Shao, Baiqi; You, Hongpeng

    2015-03-16

    A series of Eu(2+) -, Ce(3+) -, and Tb(3+) -doped Ca2 Ga2 SiO7 phosphors is synthesized by using a high-temperature solid-state reaction. The powder X-ray diffraction and structure refinement data indicate that our prepared phosphors are single phased and the phosphor crystalizes in a tetrahedral system with the ${P\\bar 42m}$ (113) space group. The Eu(2+) - and Ce(3+) -doped phosphors both have broad excitation bands, which match well with the UV light-emitting diodes chips. Under irradiation of λ=350 nm, Ca2 Ga2 SiO7 :Eu(2+) and Ca2 Ga2 SiO7 :Ce(3+) , Li(+) have green and blue emissions, respectively. Luminescence of Ca2 Ga2 SiO7 :Tb(3+) , Li(+) phosphor varies with the different Tb(3+) contents. The thermal stability and energy-migration mechanism of Ca2 Ga2 SiO7 :Eu(2+) are also studied. The investigation results indicate that the prepared Ca2 Ga2 SiO7 :Eu(2+) and Ca2 Ga2 SiO7 :Ce(3+) , Li(+) samples show potential as green and blue phosphors, respectively, for UV-excited white-light-emitting diodes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Creating responsible partnerships in tourism

    Directory of Open Access Journals (Sweden)

    Ana Spitzer

    2012-06-01

    Full Text Available RQ: Organisations do not provide sufficient time and effort to seek out companies for partners that would, with the assistance of responsible cooperation, contribute to better quality offers and consequently to increased income and the good reputation of both companies. Responsibilities and ethics is where organizations on bothsides would take on and accept their own norms, tasks, obligations and be aware that in a relationship there is a need to give explanations and justify one’s actions, such partnerships will be long and prosperous. This requires a great deal of knowledge and maturity together with a very important personal characteristic that is care. This study examines whether the creation of long term partnerships through responsible and more personal (friendlyrelations brings the organization to greater success.Purpose: The purpose of this research is to determine how important it is for organizations in the tourism industry to build long term relationships, what it should be based on and whether companies are willing to change the current methods of operations.Method: The method of research was an interview with individuals that had a certain position within a tourism company and had contacts with partners and were obligated to see out new ones. A paradigm model was built and the responses analysed.Results: The survey results are encouraging. The interviews showed that respondents were aware that it is necessary to have long term and responsible partnerships. They recognized that in today’s world there is a lack of collaboration that is based on understanding andthat there should be more relations on a personal level. It isrequired that this changes in the future. The participants specifically highlight financial irresponsibility in many companies that destroys collaboration.Organization: With the help of this study, the author attempts to contribute ideas to organizations on how to create solid collaboration with partners, as

  13. A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B. C.; Melosh, H. J. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Thebault, P. [LESIA, Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Henning, W. G. [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Gaidos, E. [Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Elkins-Tanton, L. T. [Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States); Bridges, J. C. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Morlok, A., E-mail: johns477@purdue.edu [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2012-12-10

    Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10{sup 19} kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at {approx}6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that {approx}10{sup 47} molecules of SiO vapor are needed to explain an emission feature at {approx}8 {mu}m in the Spitzer IRS spectrum of HD 172555. We find that unless there are {approx}10{sup 48} atoms or 0.05 M{sub Circled-Plus} of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the {approx}8 {mu}m feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

  14. A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

    International Nuclear Information System (INIS)

    Johnson, B. C.; Melosh, H. J.; Lisse, C. M.; Chen, C. H.; Wyatt, M. C.; Thebault, P.; Henning, W. G.; Gaidos, E.; Elkins-Tanton, L. T.; Bridges, J. C.; Morlok, A.

    2012-01-01

    Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10 19 kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at ∼6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that ∼10 47 molecules of SiO vapor are needed to explain an emission feature at ∼8 μm in the Spitzer IRS spectrum of HD 172555. We find that unless there are ∼10 48 atoms or 0.05 M ⊕ of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the ∼8 μm feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

  15. Theories of fission gas behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Dias, J W.C. [Companhia Brasileira de Tecnologia Nuclear, Rio de Janeiro (Brazil). Diretoria de Tecnologia e Desenvolvimento; Merckx, K R

    1976-01-01

    A review is presented of the theoretical developments and experimental evidence that have helped to evolve current models used to describe the behavior of inert fission gases created during the irradiation of reactor fuel materials. The phenomena which are stressed relate primarily to steady state behavior of fuel elements but are also relevant to an understanding of transient behavior. The processes considered include gas atom solubility; gas atom diffusivity; bubble nucleation; and bubble growth by bubble coalescence.

  16. SIOS: A regional cooperation of international research infrastructures as a building block for an Arctic observing system

    Science.gov (United States)

    Holmen, K. J.; Lønne, O. J.

    2016-12-01

    The Svalbard Integrated Earth Observing System (SIOS) is a regional response to the Earth System Science (ESS) challenges posed by the Amsterdam Declaration on Global Change. SIOS is intended to develop and implement methods for how observational networks in the Arctic are to be designed in order to address such issues in a regional scale. SIOS builds on the extensive observation capacity and research installations already in place by many international institutions and will provide upgraded and relevant Observing Systems and Research Facilities of world class in and around Svalbard. It is a distributed research infrastructure set up to provide a regional observational system for long term measurements under a joint framework. As one of the large scale research infrastructure initiatives on the ESFRI roadmap (European Strategy Forum on Research Infrastructures), SIOS is now being implemented. The new research infrastructure organization, the SIOS Knowledge Center (SIOS-KC), is instrumental in developing methods and solutions for setting up its regional contribution to a systematically constructed Arctic observational network useful for global change studies. We will discuss cross-disciplinary research experiences some case studies and lessons learned so far. SIOS aims to provide an effective, easily accessible data management system which makes use of existing data handling systems in the thematic fields covered by SIOS. SIOS will, implement a data policy which matches the ambitions that are set for the new European research infrastructures, but at the same time be flexible enough to consider `historical' legacies. Given the substantial international presence in the Svalbard archipelago and the pan-Arctic nature of the issue, there is an opportunity to build SIOS further into a wider regional network and pan-Arctic context, ideally under the umbrella of the Sustaining Arctic Observing Networks (SAON) initiative. It is necessary to anchor SIOS strongly in a European

  17. Role of the interface region on the optoelectronic properties of silicon nanocrystals embedded in SiO2

    International Nuclear Information System (INIS)

    Daldosso, N.; Dalba, G.; Fornasini, P.; Grisenti, R.; Pavesi, L.; Luppi, M.; Magri, R.; Ossicini, S.; Degoli, E.; Rocca, F.; Boninelli, S.; Priolo, F.; Spinella, C.; Iacona, F.

    2003-01-01

    Light-emitting silicon nanocrystals embedded in SiO 2 have been investigated by x-ray absorption measurements in total electron and photoluminescence yields, by energy filtered transmission electron microscopy and by ab initio total energy calculations. Both experimental and theoretical results show that the interface between the silicon nanocrystals and the surrounding SiO 2 is not sharp: an intermediate region of amorphous nature and variable composition links the crystalline Si with the amorphous stoichiometric SiO 2 . This region plays an active role in the light-emission process

  18. Ultralow-density SiO2 aerogels prepared by a two-step sol-gel process

    International Nuclear Information System (INIS)

    Wang Jue; Li Qing; Shen Jun; Zhou Bin; Chen Lingyan; Jiang; Weiyang

    1996-01-01

    Low density SiO 2 gels are prepared by a two-step sol-gel process from TEOS. The influence of various solution ratios on the gelation process is investigated. The comparative characterization of gels using different solvent, such as ethanol, acetone and methyl cyanide, is also given. The ultralow-density SiO 2 aerogels with density less than 10 kg/m 3 are prepared by CO 2 supercritical drying technique. The structure difference between SiO 2 aerogels prepared by conventional single-step process and the two-step process is also presented

  19. Morphology of SiO2 films as a key factor in alignment of liquid crystals with negative dielectric anisotropy

    Directory of Open Access Journals (Sweden)

    Volodymyr Tkachenko

    2016-11-01

    Full Text Available Control of liquid crystal (LC orientation using a proper SiO2 alignment layer is essential for the optimization of vertically aligned nematic (VAN displays. With this aim, we studied the optical anisotropy of thin SiO2 films by generalized ellipsometry as a function of deposition angle. The columnar SiO2 structure orientation measured by a noninvasive ellipsometry technique is reported for the first time, and its morphology influence on the LC alignment is demonstrated for large deposition angles.

  20. Identification of conduction and hot electron property in ZnS, ZnO and SiO2

    International Nuclear Information System (INIS)

    Huang Jinzhao; Xu Zheng; Zhao Suling; Li Yuan; Yuan Guangcai; Wang Yongsheng; Xu Xurong

    2007-01-01

    The impact excitation and ionization is the most important process in layered optimization scheme and solid state cathodoluminescence. The conduction property (semiconductor property) of SiO 2 , ZnS and ZnO is studied based on organic/inorganic electroluminescence. The hot electron property (acceleration and multiplication property) of SiO 2 and ZnS is investigated based on the solid state cathodoluminescence. The results show that the SiO 2 has the fine hot electron property and the conduction property is not as good as ZnO and ZnS

  1. Creating experimental color harmony map

    Science.gov (United States)

    Chamaret, Christel; Urban, Fabrice; Lepinel, Josselin

    2014-02-01

    Starting in the 17th century with Newton, color harmony is a topic that did not reach a consensus on definition, representation or modeling so far. Previous work highlighted specific characteristics for color harmony on com- bination of color doublets or triplets by means of a human rating on a harmony scale. However, there were no investigation involving complex stimuli or pointing out how harmony is spatially located within a picture. The modeling of such concept as well as a reliable ground-truth would be of high value for the community, since the applications are wide and concern several communities: from psychology to computer graphics. We propose a protocol for creating color harmony maps from a controlled experiment. Through an eye-tracking protocol, we focus on the identification of disharmonious colors in pictures. The experiment was composed of a free viewing pass in order to let the observer be familiar with the content before a second pass where we asked "to search for the most disharmonious areas in the picture". Twenty-seven observers participated to the experiments that was composed of a total of 30 different stimuli. The high inter-observer agreement as well as a cross-validation confirm the validity of the proposed ground-truth.

  2. Creating a winning organizational culture.

    Science.gov (United States)

    Campbell, Robert James

    2009-01-01

    This article explores the idea of how to create a winning organizational culture. By definition, a winning organizational culture is one that is able to make current innovations stick, while continuously changing based on the demands of the marketplace. More importantly, the article explores the notion that a winning organizational culture can have a profound impact on the conscious of the workforce, helping each individual to become a better, more productive person, who provides important services and products to the community. To form a basis toward defining the structure of what a winning organization culture looks like, 4 experts were asked 12 questions related to the development of an organizational culture. Three of the experts have worked intimately within the health care industry, while a fourth has been charged with turning around an organization that has had a losing culture for 17 years. The article provides insight into the role that values, norms, goals, leadership style, familiarity, and hiring practices play in developing a winning organizational culture. The article also emphasizes the important role that leaders perform in developing an organizational culture.

  3. Thickness and composition of ultrathin SiO2 layers on Si

    International Nuclear Information System (INIS)

    Marel, C. van der; Verheijen, M.A.; Tamminga, Y.; Pijnenburg, R.H.W.; Tombros, N.; Cubaynes, F.

    2004-01-01

    Ultrathin SiO 2 layers are of importance for the semiconductor industry. One of the techniques that can be used to determine the chemical composition and thickness of this type of layers is x-ray photoelectron spectroscopy (XPS). As shown by Seah and Spencer [Surf. Interface Anal. 33, 640 (2002)], it is not trivial to characterize this type of layer by means of XPS in a reliable way. We have investigated a series of ultrathin layers of SiO 2 on Si (in the range from 0.3 to 3 nm) using XPS. The samples were also analyzed by means of transmission electron microscopy (TEM), Rutherford backscattering (RBS), and ellipsometry. The thickness of the SiO 2 layers (d) was determined from the XPS results using three different approaches: the 'standard' equation (Seah and Spencer) for d, an overlayer-substrate model calculation, and the QUASES-Tougaard [Surf. Interface Anal. 26, 249 (1998), QUASES-Tougaard: Software package for Quantitative Analysis of Surfaces by Electron Spectroscopy, version 4.4 (2000); http://www.quases.com] method. Good agreement was obtained between the results of XPS analyses using the 'standard' equation, the overlayer-substrate model calculation, and RBS results. The QUASES-Tougaard results were approximately 62% above the other XPS results. The optical values for the thickness were always slightly higher than the thickness according to XPS or RBS. Using the model calculation, these (relatively small) deviations from the optical results could be explained as being a consequence of surface contaminations with hydrocarbons. For a thickness above 2.5 nm, the TEM results were in good agreement with the results obtained from the other techniques (apart from QUASES-Tougaard). Below 2.5 nm, significant deviations were found between RBS, XPS, and optical data on the one hand and TEM results on the other hand; the deviations became larger as the thickness of the SiO 2 decreased. This effect may be related to interface states of oxygen, which have been

  4. Enhancement of H2-sensing Properties of F-doped SnO2 Sensorby Surface Modification with SiO2

    Directory of Open Access Journals (Sweden)

    S. P. Khatkar

    2006-05-01

    Full Text Available Effects of surface chemical modification with sodium silicate on the gas-sensingproperties of F-doped SnO2 gas sensor designed and fabricated employing micro-electromechanical system (MEMS technology were investigated. Gas sensing properties of thesensor were checked against combustible gases like H2, CO, CH4 and C3H8 at a heatervoltage of 0.7 V. The H2 sensitivity of the surface modified F-doped SnO2 micro sensormarkedly increased and reached S = 175 which was found to be about 40 times more thanthat of unmodified sensor (S = ~ 4.2. The increase in the sensitivity is discussed in terms ofincreased resistivity and reduced permeation of gaseous oxygen into the underlying sensinglayer due to the surface modification of the sensor. The present micro-hydrogen sensor withenhanced sensitivity due to SiO2 incorporation is a low energy consuming portable sensormodule that can be mass-produced using MEMS technology at low cost.

  5. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  6. Requirements for gas quality and gas appliances

    NARCIS (Netherlands)

    Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

    2015-01-01

    Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

  7. Gas magnetometer

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  8. Gas separating

    Science.gov (United States)

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  9. Effects of Mev Si Ions and Thermal Annealing on Thermoelectric and Optical Properties of SiO2/SiO2+Ge Multi-nanolayer thin Films

    Science.gov (United States)

    Budak, S.; Alim, M. A.; Bhattacharjee, S.; Muntele, C.

    Thermoelectric generator devices have been prepared from 200 alternating layers of SiO2/SiO2+Ge superlattice films using DC/RF magnetron sputtering. The 5 MeV Si ionsbombardmenthasbeen performed using the AAMU Pelletron ion beam accelerator to formquantum dots and / or quantum clusters in the multi-layer superlattice thin films to decrease the cross-plane thermal conductivity, increase the cross-plane Seebeck coefficient and increase the cross-plane electrical conductivity to increase the figure of merit, ZT. The fabricated devices have been annealed at the different temperatures to tailor the thermoelectric and optical properties of the superlattice thin film systems. While the temperature increased, the Seebeck coefficient continued to increase and reached the maximum value of -25 μV/K at the fluenceof 5x1013 ions/cm2. The decrease in resistivity has been seen between the fluence of 1x1013 ions/cm2 and 5x1013 ions/cm2. Transport properties like Hall coefficient, density and mobility did not change at all fluences. Impedance spectroscopy has been used to characterize the multi-junction thermoelectric devices. The loci obtained in the C*-plane for these data indicate non-Debye type relaxation displaying the presence of the depression parameter.

  10. An amorphous Si-O film tribo-induced by natural hydrosilicate powders on ferrous surface

    International Nuclear Information System (INIS)

    Zhang, Baosen; Xu, Binshi; Xu, Yi; Ba, Zhixin; Wang, Zhangzhong

    2013-01-01

    The tribological properties of surface-coated serpentine powders suspended in oil were evaluated using an Optimal SRV-IV oscillating friction and wear tester. The worn surface and the tribo-induced protective film were characterized by scanning electron microscope and focused ion beam (SEM/FIB) work station, energy dispersive spectroscopy (EDS) and transmission electron microscope (TEM). Results indicate that with 0.5 wt% addition of serpentine powders to oil, the friction coefficient and wear rate significantly decrease referenced to those of the base oil alone. An amorphous SiO x film with amorphous SiO x particles inserted has formed on the worn surface undergoing the interactions between serpentine particles and friction surfaces. The protective film with excellent lubricating ability and mechanical properties is responsible for the reduced friction and wear.

  11. Enhanced formation of Ge nanocrystals in Ge : SiO2 layers by swift heavy ions

    International Nuclear Information System (INIS)

    Antonova, I V; Volodin, V A; Marin, D M; Skuratov, V A; Smagulova, S A; Janse van Vuuren, A; Neethling, J; Jedrzejewski, J; Balberg, I

    2012-01-01

    In this paper we report the ability of swift heavy Xe ions with an energy of 480 MeV and a fluence of 10 12 cm -2 to enhance the formation of Ge nanocrystals within SiO 2 layers with variable Ge contents. These Ge-SiO 2 films were fabricated by the co-sputtering of Ge and quartz sources which followed various annealing procedures. In particular, we found that the irradiation of the Ge : SiO 2 films with subsequent annealing at 500 °C leads to the formation of a high concentration of nanocrystals (NCs) with a size of 2-5 nm, whereas without irradiation only amorphous inclusions were observed. This effect, as evidenced by Raman spectra, is enhanced by pre-irradiation at 550 °C and post-irradiation annealing at 600 °C, which also leads to the observation of room temperature visible photoluminescence. (paper)

  12. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO2

    International Nuclear Information System (INIS)

    Stepina, N. P.; Dvurechenskii, A. V.; Armbrister, V. A.; Kesler, V. G.; Novikov, P. L.; Gutakovskii, A. K.; Kirienko, V. V.; Smagina, Zh. V.; Groetzschel, R.

    2007-01-01

    Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO 2 film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO 2 surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density

  13. Refractories in the Al2O3-ZrO2-SiO2 system

    International Nuclear Information System (INIS)

    Banerjee, S.P.; Bhadra, A.K.; Sircar, N.R.

    1978-01-01

    The effect of addition of ZrO 2 in different proportions in the refractories of the Al 2 O 3 -SiO 2 system was studied. The investigation was confined to two broad ranges of compositions incorporating zirconia (15-30 percent and 80-85 percent) in the Al 2 O 3 -ZrO 2 -SiO 2 system. The overall attainment of properties is dependent upon the mode of fabrication and firing, and bears a relationship with the phase assemblages and the relative proportion thereof. Of the different characteristics, the trend of dissociation of zircon has been found to be specially significant vis-a-vis the temperature of firing and thermal shock resistance. Reassociation of the dissociated products has been ascribed to bring forth improved resistance to thermal spalling. The different products developed during this investigation are considered to be very promising which find useful applications in view of the properties attained by them. (auth.)

  14. Mecanismos de hidratação do óxido de magnésio

    OpenAIRE

    Amaral,L. F.; Salomão,R.; Frollini,E.; Pandolfelli,V. C.

    2007-01-01

    O óxido de magnésio, MgO, é uma importante matéria-prima para a indústria de refratários por ser um material de elevada refratariedade (ponto de fusão próximo a 2800 °C), resistente a escórias básicas, e de custo competitivo. No entanto, em presença de água, o MgO rapidamente se hidrata formando hidróxido de magnésio, Mg(OH)2. Essa reação leva a uma expansão volumétrica de até três vezes, limitando sua aplicação em concretos refratários. Para desenvolver soluções que minimizem este problema, ...

  15. Atmospheric Plasma Deposition of SiO2 Films for Adhesion Promoting Layers on Titanium

    Directory of Open Access Journals (Sweden)

    Liliana Kotte

    2014-12-01

    Full Text Available This paper evaluates the deposition of silica layers at atmospheric pressure as a pretreatment for the structural bonding of titanium (Ti6Al4V, Ti15V3Cr3Sn3Al in comparison to an anodizing process (NaTESi process. The SiO2 film was deposited using the LARGE plasma source, a linearly extended DC arc plasma source and applying hexamethyldisiloxane (HMDSO as a precursor. The morphology of the surface was analyzed by means of SEM, while the characterization of the chemical composition of deposited plasma layers was done by XPS and FTIR. The long-term durability of bonded samples was evaluated by means of a wedge test in hot/wet condition. The almost stoichiometric SiO2 film features a good long-term stability and a high bonding strength compared to the films produced with the wet-chemical NaTESi process.

  16. Electron irradiation response on Ge and Al-doped SiO 2 optical fibres

    Science.gov (United States)

    Yaakob, N. H.; Wagiran, H.; Hossain, I.; Ramli, A. T.; Bradley, D. A.; Hashim, S.; Ali, H.

    2011-05-01

    This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

  17. Formation of nucleoplasmic protein aggregates impairs nuclear function in response to SiO2 nanoparticles

    International Nuclear Information System (INIS)

    Chen Min; Mikecz, Anna von

    2005-01-01

    Despite of their exponentially growing use, little is known about cell biological effects of nanoparticles. Here, we report uptake of silica (SiO 2 ) nanoparticles to the cell nucleus where they induce aberrant clusters of topoisomerase I (topo I) in the nucleoplasm that additionally contain signature proteins of nuclear domains, and protein aggregation such as ubiquitin, proteasomes, cellular glutamine repeat (polyQ) proteins, and huntingtin. Formation of intranuclear protein aggregates (1) inhibits replication, transcription, and cell proliferation; (2) does not significantly alter proteasomal activity or cell viability; and (3) is reversible by Congo red and trehalose. Since SiO 2 nanoparticles trigger a subnuclear pathology resembling the one occurring in expanded polyglutamine neurodegenerative disorders, we suggest that integrity of the functional architecture of the cell nucleus should be used as a read out for cytotoxicity and considered in the development of safe nanotechnology

  18. Photorefractive grating formation in piezoelectric La3Ga5SiO14:Pr3+ crystals

    DEFF Research Database (Denmark)

    Dam-Hansen, C.; Johansen, P.M.; Fridkin, V.M.

    1996-01-01

    Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown and compa......Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown...... and compared favorably with the theoretical expression. This photorefractive material provides a possibility for separate investigations of the charge migration processes responsible for the photorefractive effect. (C) 1996 American Institute of Physics....

  19. Annealing characteristics of SiO2-Si structures after incoherent light pulse processing

    International Nuclear Information System (INIS)

    Sieber, N.; Klabes, R.; Voelskow, M.; Fenske, F.

    1982-01-01

    The behaviour of oxide charges and interface charges in boron implanted and non-implanted SiO 2 -Si structures as well as the electrical activation of the dopants by the action of incoherent light pulses was studied. Depth profiles of electrically active boron ions are presented for different annealing conditions as measured by the pulsed C-V method. It can be concluded that exposure of MOS structures to intense radiation of flash lamps does not increase the fixed charge and the fast state density at the SiO 2 -Si interface if optimal annealing conditions (energy densities) are employed. Low dose boron implanted silicon can be electrically activated without diffusion or segregation of dopants

  20. Diffusion limited Cu and Au nanocrystal formation in thin film SiO2

    International Nuclear Information System (INIS)

    Johannessen, B.; Kluth, P.; Glover, C.J.; Foran, G.J.; Ridgway, M.C.

    2006-01-01

    Elemental Cu and Au nanocrystals (NCs) were produced by high-energy ion-implantations into amorphous silica (SiO 2 ) and subsequent thermal annealing. By a combination of X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM) we confirm both NC species to have the bulk face-centered cubic phase and estimate their average diameter. We concentrate on the investigation of the concentration and size-dependent coordination number (China) of these matrix embedded NCs utilising extended X-ray absorption fine structure (EXAFS) spectroscopy. The CN is found to be suppressed compared to that of a bulk standard. The CN in Au NCs is found to be lower than that of Cu NCs in agreement with smaller average Au NC sizes. We explain this difference by the difference in diffusivity for the two atomic species in SiO 2

  1. Thermally tunable VO2-SiO2 nanocomposite thin-film capacitors

    Science.gov (United States)

    Sun, Yifei; Narayanachari, K. V. L. V.; Wan, Chenghao; Sun, Xing; Wang, Haiyan; Cooley, Kayla A.; Mohney, Suzanne E.; White, Doug; Duwel, Amy; Kats, Mikhail A.; Ramanathan, Shriram

    2018-03-01

    We present a study of co-sputtered VO2-SiO2 nanocomposite dielectric thin-film media possessing continuous temperature tunability of the dielectric constant. The smooth thermal tunability is a result of the insulator-metal transition in the VO2 inclusions dispersed within an insulating matrix. We present a detailed comparison of the dielectric characteristics of this nanocomposite with those of a VO2 control layer and of VO2/SiO2 laminate multilayers of comparable overall thickness. We demonstrated a nanocomposite capacitor that has a thermal capacitance tunability of ˜60% between 25 °C and 100 °C at 1 MHz, with low leakage current. Such thermally tunable capacitors could find potential use in applications such as sensing, thermal cloaks, and phase-change energy storage devices.

  2. Electron irradiation response on Ge and Al-doped SiO2 optical fibres

    International Nuclear Information System (INIS)

    Yaakob, N.H.; Wagiran, H.; Hossain, I.; Ramli, A.T.; Bradley, D.A; Hashim, S.; Ali, H.

    2011-01-01

    This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

  3. Microwave absorption properties and mechanism of cagelike ZnO /SiO2 nanocomposites

    Science.gov (United States)

    Cao, Mao-Sheng; Shi, Xiao-Ling; Fang, Xiao-Yong; Jin, Hai-Bo; Hou, Zhi-Ling; Zhou, Wei; Chen, Yu-Jin

    2007-11-01

    In this paper, cagelike ZnO /SiO2 nanocomposites were prepared and their microwave absorption properties were investigated in detail. Dielectric constants and losses of the pure cagelike ZnO nanostructures were measured in a frequency range of 8.2-12.4GHz. The measured results indicate that the cagelike ZnO nanostructures are low-loss material for microwave absorption in X band. However, the cagelike ZnO /SiO2 nanocomposites exhibit a relatively strong attenuation to microwave in X band. Such strong absorption is related to the unique geometrical morphology of the cagelike ZnO nanostructures in the composites. The microcurrent network can be produced in the cagelike ZnO nanostructures, which contributes to the conductive loss.

  4. XPS studies of SiO2 surface layers formed by oxygen ion implantation into silicon

    International Nuclear Information System (INIS)

    Schulze, D.; Finster, J.

    1983-01-01

    SiO 2 surface layers of 160 nm thickness formed by 16 O + ion implantation into silicon are examined by X-ray photoelectron spectroscopy measurements into the depth after a step-by-step chemical etching. The chemical nature and the thickness of the transition layer were determined. The results of the XPS measurements show that the outer surface and the bulk of the layers formed by oxygen implantation and subsequent high temperature annealing consist of SiO 2 . There is no evidence for Si or SiO/sub x/ (0 2 and Si is similar to that of thin grown oxide layers. Only its thickness is somewhat larger than in thermal oxide

  5. Density gradient in SiO 2 films on silicon as revealed by positron annihilation spectroscopy

    Science.gov (United States)

    Revesz, A. G.; Anwand, W.; Brauer, G.; Hughes, H. L.; Skorupa, W.

    2002-06-01

    Positron annihilation spectroscopy of thermally grown and deposited SiO 2 films on silicon shows in a non-destructive manner that these films have a gradient in their density. The gradient is most pronounced for the oxide grown in dry oxygen. Oxidation in water-containing ambient results in an oxide with reduced gradient, similarly to the gradient in the deposited oxide. These observations are in accordance with earlier optical and other studies using stepwise etching or a set of samples of varying thickness. The effective oxygen charge, which is very likely one of the reasons for the difference in the W parameters of silica glass and quartz crystal, could be even higher at some localized configurations in the SiO 2 films resulting in increased positron trapping.

  6. Effect of annealing induced residual stress on the resonance frequency of SiO2 microcantilevers

    Science.gov (United States)

    Balasubramanian, S.; Prabakar, K.; Tripura Sundari, S.

    2018-04-01

    In the present work, effect of residual stress, induced due to annealing of SiO2 microcantilevers (MCs) on their resonance frequency is studied. SiO2MCs of various dimensions were fabricated using direct laser writer & wet chemical etching method and were annealed at 800 °C in oxygen environment, post release. The residual stress was estimated from the deflection profile of the MCs measured using 3D optical microscope, before and after annealing. Resonance frequency of the MCs was measured using nano-vibration analyzer and was found to change after annealing. Further the frequency shift was found to depend on the MC dimensions. This is attributed to the large stress gradients induced by annealing and associated stiffness changes.

  7. Experimental observations of the chemistry of the SiO2/Si interface

    Science.gov (United States)

    Grunthaner, F. J.; Maserjian, J.

    1977-01-01

    Changes in silicon surface preparation prior to thermal oxidation are shown to leave a signature by altering the final SiO2/Si interface structure. Surface analytical techniques, including XPS, static SIMS, ion milling, and newly developed wet-chemical profiling procedures are used to obtain detailed information on the chemical structure of the interface. The oxides are shown to be essentially SiO2 down to a narrow transitional interface layer (3-7 A). A number of discrete chemical species are observed in this interface layer, including different silicon bonds (e.g., C-, OH-, H-) and a range of oxidation states of silicon (0 to +4). The effect of surface preparation and the observed chemical species are correlated with oxide growth rate, surface-state density, and flatband shifts after irradiation.

  8. Light emissions from LiNbO sub 3 /SiO sub 2 /Si structures

    CERN Document Server

    Wu, X L; Tang, N; Deng, S S; Bao, X M

    2003-01-01

    LiNbO sub 3 (LN) films with a high degree of (006) texture were deposited on Si-based dense SiO sub 2 layers by pulsed laser deposition. After annealing, the LN/SiO sub 2 /Si structures were revealed to have ultraviolet-, green-, and red-emitting properties related to self-trapped excitons and E' defect pairs in the SiO sub 2 surface, which are induced by the photorefractive effect of the LN films. The emission wavelength can be tuned by introducing different dopants into the LN films. Waveguiding properties of the structures were demonstrated. The results obtained indicate that the LN/SiO sub 2 /Si structures could be expected to have important applications in modern optoelectronic integration. (letter to the editor)

  9. New oil and gas contract in Colombia

    International Nuclear Information System (INIS)

    Carta Petrolera

    2004-01-01

    The Colombian government has implemented two fundamental changes in the upstream oil and gas industry, Ecopetrol role is now as sole entrepreneur and the national hydrocarbons agency - ANH was created to administer the hydrocarbons resource

  10. Thinning of Inner Retinal Layers after Vitrectomy with Silicone Oil versus Gas Endotamponade in Eyes with Macula-Off Retinal Detachment.

    Science.gov (United States)

    Purtskhvanidze, Konstantine; Hillenkamp, Jost; Tode, Jan; Junge, Olaf; Hedderich, Jürgen; Roider, Johann; Treumer, Felix

    2017-01-01

    To evaluate retinal layer thickness with optical coherence tomography (OCT) in eyes with macula-off retinal detachment after silicone oil (SiO) or gas endotamponade. Cross-sectional study of 40 eyes with macula-off rhegmatogenous retinal detachment that underwent vitrectomy. 20 eyes received SiO tamponade and 20 matched eyes received gas. 33 healthy fellow eyes served as controls. Macular spectral domain OCT was performed with automated layer detection in the 5 inner subfields of the Early Treatment Diabetic Retinopathy Study (ETDRS) map. Comparing the SiO group with the gas group, the ganglion cell layer showed a significant thinning in all fields of the inner ring of the ETDRS map, the inner plexiform layer in the nasal, superior and temporal quadrants, and the outer plexiform layer in the nasal quadrant. Inner retinal layers in the fovea/parafovea were significantly thinner in the SiO group. Prospective studies are warranted to further elucidate possible retinal adverse effects of SiO tamponade. © 2017 S. Karger AG, Basel.

  11. Ca2 Al2 SiO7 :Ce3+ phosphors for mechanoluminescence dosimetry.

    Science.gov (United States)

    Tiwari, Geetanjali; Brahme, Nameeta; Sharma, Ravi; Bisen, D P; Sao, Sanjay Kumar; Sahu, Ishwar Prasad

    2016-12-01

    A series of Ce 3+ ion single-doped Ca 2 Al 2 SiO 7 phosphors was synthesized by a combustion-assisted method at an initiating temperature of 600 °C. The samples were annealed at 1100 °C for 3 h and their X-ray diffraction patterns confirmed a tetragonal structure. The phase structure, particle size, surface morphology and elemental analysis were analyzed using X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy techniques. Thermoluminescence (TL) intensity increased with increase in ultraviolet (UV) light exposure time up to 15 min. With further increase in the UV irradiation time the TL intensity decreases. The increase in TL intensity indicates that trap concentration increased with UV exposure time. A broad peak at 121 °C suggested the existence of a trapping level. The peak of mechanoluminescence (ML) intensity versus time curve increased linearly with increasing impact velocity of the moving piston. Mechanoluminescence intensity increased with increase in UV irradiation time up to 15 min. Under UV-irradiation excitation, the TL and ML emission spectra of Ca 2 Al 2 SiO 7 :Ce 3+ phosphor showed the characteristic emission of Ce 3+ peaking at 400 nm (UV-violet) and originating from the Ce 3+ transitions of 5d-4f ( 2 F 5/2 and 2 F 7/2 ). The photoluminescence (PL) emission spectra for Ca 2 Al 2 SiO 7 :Ce 3+ were similar to the ML/TL emission spectra. The mechanism of ML excitation and the suitability of the Ca 2 Al 2 SiO 7 :Ce 3+ phosphor for radiation dosimetry are discussed. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. A novel growth mode of alkane films on a SiO2 surface

    DEFF Research Database (Denmark)

    Mo, H.; Taub, H.; Volkmann, U.G.

    2003-01-01

    on the SiO2 surface with the long-axis of the C32 molecules oriented parallel to the interface followed by a C32 monolayer with the long-axis perpendicular to it. Finally, preferentially oriented bulk particles nucleate having two different crystal structures. This growth model differs from that found...... previously for shorter alkanes deposited from the vapor phase onto solid surfaces....

  13. Absorption of acoustic waves in La3Ga5SiO14 monocrystals

    International Nuclear Information System (INIS)

    Mansfel'd, G.D.; Bezdelkin, V.V.; Freik, A.D.; Kucheryavaya, E.S.

    1995-01-01

    Frequency dependences of longitudinal and transverse acoustic wave absorption coefficient in the basic crystallographic La 3 Ga 5 SiO 14 directions are measured by composite resonator method. The obtained values of absorption coefficient for all directions appear to be lower or approximately equal to the values of absorption coefficient in quartz monocrystals. Application of the resonator methods allows one to study factors affecting the resonator high-quality as well. 9 refs., 4 figs

  14. Positron mobility in thermally grown SiO2 measured by Doppler broadening technique

    International Nuclear Information System (INIS)

    Kong, Y.; Leung, T.C.; Asoka-Kumar, P.; Nielsen, B.; Lynn, K.G.

    1991-01-01

    The positron mobility in thermally grown SiO 2 is deduced from Doppler broadening lineshape data on a metal-oxide-semiconductor sample for positrons implanted into the oxide layer. The fitted mobility is ∼13(10)x10 -3 cm 2 /s V. This value is between that of the electron and hole mobilities in the same system and is two orders of magnitude smaller than the previous estimate from positron measurements

  15. Study of hydrogen interaction with SiO2/Si(100) system using positrons

    International Nuclear Information System (INIS)

    Asoka-Kumar, P.; Lynn, K.G.; Leung, T.C.; Nielsen, B.; Wu, X.Y.

    1991-01-01

    We describe positron annihilation studies of SiO 2 /Si(100) structures having 100-nm-thick oxide grown by plasma enhanced chemical vapor deposition. A normalized shape parameter is used to characterize the positron annihilation spectra. Activation and passivation of interface states by atomic hydrogen are demonstrated by repeated vacuum anneal and atomic hydrogen exposure. Hydrogen activation energy is derived for one of the samples as 2.02±0.07 eV

  16. Photocatalytic Removal of Phenol under Natural Sunlight over N-TiO2-SiO2 Catalyst: The Effect of Nitrogen Composition in TiO2-SiO2

    Directory of Open Access Journals (Sweden)

    Viet-Cuong Nguyen

    2009-01-01

    Full Text Available In this present work, high specific surface area and strong visible light absorption nitrogen doped TiO2-SiO2 photocatalyst was synthesized by using sol-gel coupled with hydrothermal treatment method. Nitrogen was found to improve the specific surface area while it also distorted the crystal phase of the resulting N-TiO2-SiO2 catalyst. As the N/ (TiO2-SiO2 molar ratio was more than 10%, the derived catalyst presented the superior specific surface area up to 260 m2/g. Nevertheless, its photoactivity towards phenol removal was observed to significantly decrease, which could results from the too low crystallinity. The nitrogen content in N-TiO2-SiO2 catalyst was therefore necessary to be optimized in terms of phenol removal efficiency and found at ca. 5%. Under UVA light and natural sunlight irradiation of 80 min, N(5%-TiO2-SiO2 catalyst presented the phenol decomposition efficiencies of 68 and 100%, respectively. It was also interestingly found in this study that the reaction rate was successfully expressed using a Langmuir-Hinshelwood (L-H model, indicating the L-H nature of photocatalytic phenol decomposition reaction on the N-TiO2-SiO2 catalyst.

  17. The impact of northern gas on North American gas infrastructure

    International Nuclear Information System (INIS)

    Letwin, S.

    2004-01-01

    The three business units that Enbridge operates are crude oil pipelines; natural gas liquids (NGL) transportation; and gas transmission and distribution. The need for more infrastructure will increase as the demand for natural gas increases. This presentation outlined the issues that surround and sometimes impede infrastructure development. It also emphasized the need for northern gas supply at a time when conventional natural gas supplies are decreasing and demand is growing. Additional LNG supply is required along with new supply from Alaska, Mackenzie Delta and the east coast. The issue of a secure source of supply was discussed along with northern gas expectations. It is expected that Mackenzie Delta gas (1.2 bcf/day) will be available by 2008 to 2010 and Alaska North Slope gas (4 bcf/day) will be available from 2012 to 2014. Gas demand by industrial, residential, commercial and power generation sectors across North America was illustrated. The challenge lies in creating infrastructure to move the supply to where it is most in demand. General infrastructure issues were reviewed, such as prices, regulatory streamlining, lead times, stakeholder issues and supporting infrastructure. 19 figs

  18. Efficient VEGF targeting delivery of DOX using Bevacizumab conjugated SiO2@LDH for anti-neuroblastoma therapy.

    Science.gov (United States)

    Zhu, Rongrong; Wang, Zhaoqi; Liang, Peng; He, Xiaolie; Zhuang, Xizhen; Huang, Ruiqi; Wang, Mei; Wang, Qigang; Qian, Yechang; Wang, Shilong

    2017-11-01

    Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and is highly expressed in carcinoma, which make it an important target for tumor targeting therapy. Neuroblastoma is the main cause for cancer-related death in children. Like most solid tumors, it is also accompanied with the overexpression of VEGF. Doxorubicin Hydrochloride (DOX), a typical chemotherapeutic agent, exhibits efficient anticancer activities for various cancers. However, DOX, without targeting ability, usually causes severe damage to normal tissues. To overcome the shortages, we designed a novel nano-composite, which is Bevacizumab (Bev) modified SiO 2 @LDH nanoparticles (SiO 2 @LDH-Bev), loading with DOX to achieve targeting ability and curative efficiency. SiO 2 @LDH-DOX and SiO 2 @LDH-Bev-DOX nanoparticles were synthesized and the physicochemical properties were characterized by TEM detection, Zeta potential analysis, FTIR, Raman and XPS analysis. Then in vitro and in vivo anti-neuroblastoma efficiency, targeting ability and mechanisms of anti-carcinoma and anti-angiogenesis of SiO 2 @LDH-Bev-DOX were explored. Our results indicated that we obtained the core-shell structure SiO 2 @LDH-Bev with an average diameter of 253±10nm and the amount of conjugated Bev was 4.59±0.38μg/mg SiO 2 @LDH-Bev. SiO 2 @LDH-Bev-DOX could improve the cellular uptake and the targeting effect of DOX to brain and tumor, enhance the anti-neuroblastoma and anti-angiogenesis efficiency both in vitro and in vivo, and alleviate side effects of DOX sharply, especially hepatic injury. In addition, we also demonstrated that angiogenesis inhibitory effect was mediated by DOX and VEGF triggered signal pathways, including PI3K/Akt, Raf/MEK/ERK, and adhesion related pathways. In summary, SiO 2 @LDH-Bev could be a potential VEGF targeting nanocarrier applied in VEGF positive cancer therapy. This paper explored that a novel core-shell structure nanomaterial SiO 2 @LDH and modified SiO 2 @LDH with

  19. SIO 76-3, Sediment Descriptions from the Studies of East Asia Tectonics and Resources (SEATAR) Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SEATAR files were compiled by the Scripps Institution of Oceanography with funds from IDOE/NSF, as part of the SIO world sediment data bank, under the direction...

  20. Manure gas

    Energy Technology Data Exchange (ETDEWEB)

    Carre, I

    1947-05-01

    A short description of the process is given, with gas yields from various feedstocks, and the composition of the gas. Short descriptions of several batch digester designs are given: Algerian, Salubra, Betur, Baudot-Hardoll and Ofta, and Somagaz. The utilization and the economics of the process are discussed. Two diagrams of Ducellier and Isman designs are included.

  1. Shock and Release Data on Forsterite (Mg2SiO4) Single Crystals

    Science.gov (United States)

    Root, S.; Townsend, J. P.; Shulenburger, L.; Davies, E.; Kraus, R. G.; Spaulding, D.; Stewart, S. T.; Jacobsen, S. B.; Mattsson, T. R.

    2016-12-01

    The Kepler mission has discovered numerous extra-solar rocky planets with sizes ranging from Earth-size to the super-Earths with masses 40 times larger than Earth. The solid solution series of (Mg, Fe)2SiO4 (olivine) is a major component in the mantle of Earth and likely these extra-solar rocky planets. However, understanding how the (Mg, Fe)2SiO4 system behaves at Earth like and super-Earth like pressures is still unknown. Using Sandia's Z machine facility, we shock compress single crystal forsterite, the Mg end-member of the olivine series. Solid aluminum flyers are accelerated up to 28 km/s to generate steady shock states up to 950 GPa. Release states from the Hugoniot are determined as well. In addition to experiments, we perform density functional theory (DFT) calculations to examine the potential phases along the Mg2SiO4 Hugoniot. We compare our results to other recent shock experiments on forsterite. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Strong piezoelectricity in single-layer graphene deposited on SiO2 grating substrates.

    Science.gov (United States)

    da Cunha Rodrigues, Gonçalo; Zelenovskiy, Pavel; Romanyuk, Konstantin; Luchkin, Sergey; Kopelevich, Yakov; Kholkin, Andrei

    2015-06-25

    Electromechanical response of materials is a key property for various applications ranging from actuators to sophisticated nanoelectromechanical systems. Here electromechanical properties of the single-layer graphene transferred onto SiO2 calibration grating substrates is studied via piezoresponse force microscopy and confocal Raman spectroscopy. The correlation of mechanical strains in graphene layer with the substrate morphology is established via Raman mapping. Apparent vertical piezoresponse from the single-layer graphene supported by underlying SiO2 structure is observed by piezoresponse force microscopy. The calculated vertical piezocoefficient is about 1.4 nm V(-1), that is, much higher than that of the conventional piezoelectric materials such as lead zirconate titanate and comparable to that of relaxor single crystals. The observed piezoresponse and achieved strain in graphene are associated with the chemical interaction of graphene's carbon atoms with the oxygen from underlying SiO2. The results provide a basis for future applications of graphene layers for sensing, actuating and energy harvesting.

  3. Slow positron studies of hydrogen activation/passivation on SiO2/Si(100) interfaces

    International Nuclear Information System (INIS)

    Lynn, K.G.; Asoka-Kumar, P.

    1991-01-01

    The hydrogen atoms are one of the most common impurity species found in semiconductor systems owing to its large diffusivity, and are easily incorporated either in a controlled process like in ion implantation or in an uncontrolled process like the one at the fabrication stage. Hydrogen can passivate dangling bonds and dislocations in these systems and hence can be used to enhance the electrical properties. In a SiO 2 /Si system, hydrogen can passivate electronic states at the interface and can alter the fixed or mobile charges in the oxide layer. Since hydrogen is present in almost all of the environments of SiO 2 /Si wafer fabrication, the activation energy of hydrogen atoms is of paramount importance to a proper understanding of SiO 2 /Si based devices and has not been measured on the technologically most important Si(100) face. There are no direct, nondestructive methods available to observe hydrogen injection into the oxide layer and subsequent diffusion. This study uses the positrons as a ''sensitive'', nondestructive probe to observe hydrogen interaction in the oxide layer and the interface region. We also describe a new way of characterizing the changes in the density of the interface states under a low-temperature annealing using positrons. 9 refs., 6 figs

  4. Slow positron studies of hydrogen activation/passivation on SiO2/Si(100) interfaces

    Science.gov (United States)

    Lynn, K. G.; Asoka-Kumar, P.

    The hydrogen atoms are one of the most common impurity species found in semiconductor systems owing to its large diffusivity, and are easily incorporated either in a controlled process like in ion implantation or in an uncontrolled process like the one at the fabrication stage. Hydrogen can passivate dangling bonds and dislocations in these systems and hence can be used to enhance the electrical properties. In a SiO2/Si system, hydrogen can passivate electronic states at the interface and can alter the fixed or mobile charges in the oxide layer. Since hydrogen is present in almost all of the environments of SiO2/Si wafer fabrication, the activation energy of hydrogen atoms is of paramount importance to a proper understanding of SiO2/Si based devices and has not been measured on the technologically most important Si(100) face. There are no direct, nondestructive methods available to observe hydrogen injection into the oxide layer and subsequent diffusion. The positrons are used as a 'sensitive', nondestructive probe to observe hydrogen interaction in the oxide layer and the interface region. A new way is described of characterizing the changes in the density of the interface states under a low temperature annealing using positrons.

  5. Improving Passivation Process of Si Nanocrystals Embedded in SiO2 Using Metal Ion Implantation

    Directory of Open Access Journals (Sweden)

    Jhovani Bornacelli

    2013-01-01

    Full Text Available We studied the photoluminescence (PL of Si nanocrystals (Si-NCs embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au, and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  6. Effects of four step sintering on Y2O3: SiO2 nanocomposite

    International Nuclear Information System (INIS)

    Ahlawat, Rachna

    2015-01-01

    Need for high performance materials for advanced applications have led to the development of new concepts in materials design processing and their fabrication. The development of nanocrystalline materials with improved and novel properties is an important turning point in materials research. In present work, we report synthesis and structural characterization of Y 2 O 3 : SiO 2 nanocomposite. Sol-gel technique is being used to prepare-Y 2 O 3 SiO 2 nanocomposite due to its effectiveness in preparing samples with good mixing of starting materials and at relatively low reaction temperature. We have used Y(NO 3 ) 3 .4H 2 O and TEOS as precursors and followed usual approach of sol-gel technique, the final product of Y 2 O 3 : SiO 2 nanocomposite is obtained in the form of powder. The powder samples were sintered at different temperature for different time durations in programmable muffle furnace. The samples were characterized by complementary techniques as X-Ray Diffraction (XRD), Fourier Transforms Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). (author)

  7. Impact of SiO2 on Al–Al thermocompression wafer bonding

    International Nuclear Information System (INIS)

    Malik, Nishant; Finstad, Terje G; Schjølberg-Henriksen, Kari; Poppe, Erik U; Taklo, Maaike M V

    2015-01-01

    Al–Al thermocompression bonding suitable for wafer level sealing of MEMS devices has been investigated. This paper presents a comparison of thermocompression bonding of Al films deposited on Si with and without a thermal oxide (SiO 2 film). Laminates of diameter 150 mm containing device sealing frames of width 200 µm were realized. The wafers were bonded by applying a bond force of 36 or 60 kN at bonding temperatures ranging from 300–550 °C for bonding times of 15, 30 or 60 min. The effects of these process variations on the quality of the bonded laminates have been studied. The bond quality was estimated by measurements of dicing yield, tensile strength, amount of cohesive fracture in Si and interfacial characterization. The mean bond strength of the tested structures ranged from 18–61 MPa. The laminates with an SiO 2 film had higher dicing yield and bond strength than the laminates without SiO 2 for a 400 °C bonding temperature. The bond strength increased with increasing bonding temperature and bond force. The laminates bonded for 30 and 60 min at 400 °C and 60 kN had similar bond strength and amount of cohesive fracture in the bulk silicon, while the laminates bonded for 15 min had significantly lower bond strength and amount of cohesive fracture in the bulk silicon. (paper)

  8. Surface Modification of SiO2 Microchannels with Biocompatible Polymer Using Supercritical Carbon Dioxide

    Science.gov (United States)

    Saito, Tatsuro; Momose, Takeshi; Hoshi, Toru; Takai, Madoka; Ishihara, Kazuhiko; Shimogaki, Yukihiro

    2010-11-01

    The surface of 500-mm-long microchannels in SiO2 microchips was modified using supercritical CO2 (scCO2) and a biocompatible polymer was coated on it to confer biocompatibility to the SiO2 surface. In this method, the SiO2 surface of a microchannel was coated with poly(ethylene glycol monomethacrylate) (PEGMA) as the biocompatible polymer using allyltriethoxysilane (ATES) as the anchor material in scCO2 as the reactive medium. Results were compared with those using the conventional wet method. The surface of a microchannel could not be modified by the wet method owing to the surface tension and viscosity of the liquid, but it was modified uniformly by the scCO2 method probably owing to the near-zero surface tension, low viscosity, and high diffusivity of scCO2. The effect of the surface modification by the scCO2 method to prevent the adsorption of protein was as high as that of the modification by the wet method. Modified microchips can be used in biochemical and medical analyses.

  9. Annealing behavior of oxygen in-diffusion from SiO2 film to silicon substrate

    International Nuclear Information System (INIS)

    Abe, T.; Yamada-Kaneta, H.

    2004-01-01

    Diffusion behavior of oxygen at (near) the Si/SiO 2 interface was investigated. We first oxidized the floating-zone-grown silicon substrates, and then annealed the SiO 2 -covered substrates in an argon ambient. We examined two different conditions for oxidation: wet and dry oxidation. By the secondary-ion-mass spectrometry, we measured the depth profiles of the oxygen in-diffusion of these heat-treated silicon substrates: We found that the energy of dissolution (in-diffusion) of an oxygen atom that dominates the oxygen concentration at the Si/SiO 2 interface depends on the oxidation condition: 2.0 and 1.7 eV for wet and dry oxidation, respectively. We also found that the barrier heights for the oxygen diffusion in argon anneal were significantly different for different ambients adopted for the SiO 2 formation: 3.3 and 1.8 eV for wet and dry oxidation, respectively. These findings suggest that the microscopic behavior of the oxygen atoms at the Si/SiO 2 interface during the argon anneal depends on the ambient adopted for the SiO 2 formation

  10. Bulk properties and near-critical behaviour of SiO2 fluid

    Science.gov (United States)

    Green, Eleanor C. R.; Artacho, Emilio; Connolly, James A. D.

    2018-06-01

    Rocky planets and satellites form through impact and accretion processes that often involve silicate fluids at extreme temperatures. First-principles molecular dynamics (FPMD) simulations have been used to investigate the bulk thermodynamic properties of SiO2 fluid at high temperatures (4000-6000 K) and low densities (500-2240 kg m-3), conditions which are relevant to protoplanetary disc condensation. Liquid SiO2 is highly networked at the upper end of this density range, but depolymerises with increasing temperature and volume, in a process characterised by the formation of oxygen-oxygen (Odbnd O) pairs. The onset of vaporisation is closely associated with the depolymerisation process, and is likely to be non-stoichiometric at high temperature, initiated via the exsolution of O2 molecules to leave a Si-enriched fluid. By 6000 K the simulated fluid is supercritical. A large anomaly in the constant-volume heat capacity occurs near the critical temperature. We present tabulated thermodynamic properties for silica fluid that reconcile observations from FPMD simulations with current knowledge of the SiO2 melting curve and experimental Hugoniot curves.

  11. Synthesis of Li2SiO3 at low temperature

    International Nuclear Information System (INIS)

    Mondragon G, G.

    2007-01-01

    The main objective of this work is to develop a new synthesis method to obtain one of the more studied ceramics in this field Li 2 SiO 3 ) in a simple and economic way using different solutions (urea and ammonium hydroxide). The particular objectives are first to prepare the Li 2 SiO 3 ceramic, by means of the use of the reaction conventional technique in solid state at temperatures between 800 and 900 C to compare it with the one proposed in this work and this way to observe the advantages that it would gives us the new method. Later on, the same one was synthesized lithium ceramic (Li 2 SiO 3 ) by means of the new method at low temperature (between 80 and 90 C), using silicic acid and lithium hydroxide like precursory reagents and different solutions (urea and ammonium hydroxide) for the optimization in their synthesis. Finally, it was carried out the characterization of these materials by means of X-ray diffraction (XRD), electronic microscopes (SEM and TEM), nitrogen physisorption (method BET) and thermal gravimetric analysis (TGA) to observe the differences that exist among the conventional method and the proposed method and by this way to determine the advantages of the last method. (Author)

  12. Characterization of Chemical Vapor Deposited Tetraethyl Orthosilicate based SiO2 Films for Photonic Devices

    Directory of Open Access Journals (Sweden)

    Jhansirani KOTCHARLAKOTA

    2016-05-01

    Full Text Available Silicon has been the choice for photonics technology because of its cost, compatibility with mass production and availability. Silicon based photonic devices are very significant from commercial point of view and are much compatible with established technology. This paper deals with deposition and characterization of SiO2 films prepared by indigenously developed chemical vapor deposition system. Ellipsometry study of prepared films showed an increase in refractive index and film thickness with the increment in deposition temperature. The deposition temperature has a significant role for stoichiometric SiO2 films, FTIR measurement has shown the three characteristics peaks of Si-O-Si through three samples prepared at temperatures 700, 750 and 800 °C while Si-O-Si stretching peak positions were observed to be shifted to lower wavenumber in accordance to the temperature. FESEM analysis has confirmed the smooth surface without any crack or disorder while EDX analysis showed the corresponding peaks of compositional SiO2 films.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7245

  13. Si-O compound formation by oxygen ion implantation into silicon

    International Nuclear Information System (INIS)

    Hensel, E.; Wollschlaeger, K.; Kreissig, U.; Skorupa, W.; Schulze, D.; Finster, J.

    1985-01-01

    High dose oxygen ion implantation into silicon at 30 keV was performed to produce understoichiometric and stoichiometric surface oxide layers of approx. 160 nm thickness. The oxygen depth profile and oxide stoichiometry was determined by RBS and XPS. Si-O compound formation was found by IR spectroscopy and XPS in the unannealed samples as well as after target heating, furnace or flash lamp annealing. As implanted understoichiometric layers consist of random bonding like SiOsub(x) (O 2 after annealing. Unannealed stoichiometric layers are bond strained SiO 2 . The activation energies of demixing and of the annealing of bond strains are determined to 0.19 and 0.13 eV, respectively. The removing of bond strains occurs at temperatures >= 800 C in a time shorter than 1 s. The SiO 2 /Si transition region of unannealed stoichiometric layers consists of SiOsub(x) with an extent of about 10 nm. After annealing this extent diminishes to 0.8 to 1 nm in consequence of oxidation by excess oxygen from the overstoichiometric oxide region. This thickness is comparable with that of thermal oxide. (author)

  14. Landfill gas

    International Nuclear Information System (INIS)

    Hartnell, Gaynor

    2000-01-01

    Following the UK Government's initiative for stimulating renewable energy through the Non-Fossil Fuel Obligation (NFFO), the UK landfill gas industry has more than trebled in size in just 4 years. As a result, UK companies are now in a strong position to offer their skills and services overseas. Ireland, Greece and Spain also resort heavily to disposal to landfill. Particularly rapid growth of the landfill gas market is expected in the OECD-Pacific and NAFTA areas. The article explains that landfill gas is a methane-rich mixture produced by anaerobic decomposition of organic wastes in landfills: under optimum conditions, up to 500 cubic meters of gas can be obtained from 1 tonne of biodegradable waste. Data on the number and capacity of sites in the UK are given. The Landfill Gas Association runs courses to counteract the skills shortage in the UK, and tailored courses for overseas visitors are planned

  15. Gas target neutron generator studies

    International Nuclear Information System (INIS)

    Chatoorgoon, V.

    1978-01-01

    The need for an intense neutron source for the study of radiation damage on materials has resulted in the proposal of various solid, liquid, and gas targets. Among the gas targets proposed have been the transonic gas target, two types of hypersonic gas target, and the subsonic gas target (SGT). It has been suggested that heat deposition in a subsonic channel might create a gas density step which would constitute an attractive gas target type. The first part of the present study examines this aspect of the SGT and shows that gas density gradients are indeed formed by heat deposition in subsonic flow. The variation of beam voltage, gas density, gas pressure, and gas temperature within the channel have been calculated as functions of the system parameters: beam voltage, beam current, channel diameter, stagnation tank temperature and pressure. The analysis is applicable to any beam particle and target gas. For the case of T + on D 2 , which is relevant to the fusion application, the 14 MeV neutron profiles are presented as a function of system parameters. It is found that the SGT is compatible with concentrated intense source operation. The possibility of instability was investigated in detail using a non-linear analysis which made it possible to follow the complete time development of the SGT. It was found that the SGT is stable against all small perturbations and certain types of large perturbations. It appears that the SGT is the most advantageous type of gas target, operating at a lower mass flow and less severe stagnation tank conditions than the other types. The second part of the thesis examines a problem associated with the straight hypersonic target, the deuterium spill into the tritium port. The regime of practical operation for this target is established. (auth)

  16. The computer simulation of 3d gas dynamics in a gas centrifuge

    Science.gov (United States)

    Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

    2016-09-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there.

  17. The computer simulation of 3d gas dynamics in a gas centrifuge

    International Nuclear Information System (INIS)

    Borman, V D; Bogovalov, S V; Borisevich, V D; Tronin, I V; Tronin, V N

    2016-01-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there. (paper)

  18. SiO MASERS AROUND WX PSC MAPPED WITH THE KVN AND VERA ARRAY (KaVA)

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Youngjoo; Cho, Se-Hyung; Kim, Jaeheon; Choi, Yoon Kyung; Kim, Dong-Jin; Yoon, Dong-Hwan; Byun, Do-Young; Chung, Hyunsoo; Chung, Moon-Hee; Han, Myoung-Hee [Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong, Daejeon 305-348 (Korea, Republic of); Imai, Hiroshi; Oyadomari, Miyako [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Asaki, Yoshiharu [National Astronomical Observatory of Japan (NAOJ) Chile Observatory/Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura 763 0355, Santiago (Chile); Chibueze, James O. [Department of Physics and Astronomy, Faculty of Physical Sciences, University of Nigeria, Carver Building, 1 University Road, Nsukka (Nigeria); Dodson, Richard; Rioja, María J. [International Centre for Radio Astronomy Research, M468, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009 (Australia); Kusuno, Kozue [Department of Space and Astronautical Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), 3-1-1 Yoshinodai, Chuou-Ku, Sagamihara, Kanagawa 252-5210 (Japan); Matsumoto, Naoko; Hagiwara, Yoshiaki [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Min, Cheulhong, E-mail: yjyun@kasi.re.kr, E-mail: cho@kasi.re.kr [Department of Astronomical Sciences, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); and others

    2016-05-01

    We present the first images of the v = 1 and v = 2 J = 1 → 0 SiO maser lines taken with KaVA, i.e., the combined array of the Korean Very Long Baseline Interferometry (VLBI) Network and the VLBI Exploration of Radio Astrometry (VERA), toward the OH/IR star WX Psc. The combination of long and short antenna baselines enabled us to detect a large number of maser spots, which exhibit a typical ring-like structure in both the v = 1 and v = 2 J = 1 → 0 SiO masers as those that have been found in previous VLBI observational results of WX Psc. The relative alignment of the v = 1 and v = 2 SiO maser spots are precisely derived from astrometric analysis, due to the absolute coordinates of the reference maser spot that were well determined in an independent astrometric observation with VERA. The superposition of the v = 1 and v = 2 maser spot maps shows a good spatial correlation between the v = 1 and v = 2 SiO maser features. Nevertheless, it is also shown that the v = 2 SiO maser spot is distributed in an inner region compared to the v = 1 SiO maser by about 0.5 mas on average. These results provide good support for the recent theoretical studies of the SiO maser pumping, in which both the collisional and the radiative pumping predict the strong spatial correlation and the small spatial discrepancy between the v = 1 and v = 2 SiO maser.

  19. Preparation and characterization of silane-modified SiO2 particles reinforced resin composites with fluorinated acrylate polymer.

    Science.gov (United States)

    Liu, Xue; Wang, Zengyao; Zhao, Chengji; Bu, Wenhuan; Na, Hui

    2018-04-01

    A series of fluorinated dental resin composites were prepared with two kinds of SiO 2 particles. Bis-GMA (bisphenol A-glycerolate dimethacrylate)/4-TF-PQEA (fluorinated acrylate monomer)/TEGDMA (triethylene glycol dimethacrylate) (40/30/30, wt/wt/wt) was introduced as resin matrix. SiO 2 nanopartices (30nm) and SiO 2 microparticles (0.3µm) were silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) and used as fillers. After mixing the resin matrix with 0%, 10%, 20%, 30% SiO 2 nanopartices and 0%, 10%, 20%, 30%, 40%, 50% SiO 2 microparticles, respectively, the fluorinated resin composites were obtained. Properties including double bond conversion (DC), polymerization shrinkage (PS), water sorption (W p ), water solubility (W y ), mechanical properties and cytotoxicity were investigated in comparison with those of neat resin system. The results showed that, filler particles could improve the overall performance of resin composites, particularly in improving mechanical properties and reducing PS of composites along with the addition of filler loading. Compared to resin composites containing SiO 2 microparticles, SiO 2 nanoparticles resin composites had higher DC, higher mechanical properties, lower PS and lower W p under the same filler content. Especially, 50% SiO 2 microparticles reinforced resins exhibited the best flexural strength (104.04 ± 7.40MPa), flexural modulus (5.62 ± 0.16GPa), vickers microhardness (37.34 ± 1.13 HV), compressive strength (301.54 ± 5.66MPa) and the lowest polymerization (3.42 ± 0.22%). Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

    Science.gov (United States)

    Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

    2015-01-01

    Fe3O4@SiO2-graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe3O4@SiO2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe3O4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe3O4@SiO2 NPs was 24 ± 0.3 nm, similar to that of Fe3O4@SiO2-NH2. Fe3O4@SiO2-GO composites were synthesized by linking of Fe3O4@SiO2-NH2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe3O4@SiO2-GO composite has potential applications in the production of bioethanol.

  1. Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

    International Nuclear Information System (INIS)

    Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

    2015-01-01

    Fe 3 O 4 @SiO 2 –graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe 3 O 4 @SiO 2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe 3 O 4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO 2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe 3 O 4 @SiO 2 NPs was 24 ± 0.3 nm, similar to that of Fe 3 O 4 @SiO 2 –NH 2 . Fe 3 O 4 @SiO 2 –GO composites were synthesized by linking of Fe 3 O 4 @SiO 2 –NH 2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe 3 O 4 @SiO 2 –GO composite has potential applications in the production of bioethanol

  2. Carboxylated SiO2-coated α-Fe nanoparticles: towards a versatile platform for biomedical applications.

    Science.gov (United States)

    Kohara, Kaori; Yamamoto, Shinpei; Seinberg, Liis; Murakami, Tatsuya; Tsujimoto, Masahiko; Ogawa, Tetsuya; Kurata, Hiroki; Kageyama, Hiroshi; Takano, Mikio

    2013-03-28

    Carboxylated SiO2-coated α-Fe nanoparticles have been successfully prepared via CaH2-mediated reduction of SiO2-coated Fe3O4 nanoparticles followed by surface carboxylation. These α-Fe-based nanoparticles, which are characterized by ease of coating with additional functional groups, a large magnetization of 154 emu per g-Fe, enhanced corrosion resistivity, excellent aqueous dispersibility, and low cytotoxicity, have potential to be a versatile platform in biomedical applications.

  3. Selective adsorption of thiophenic compounds from fuel over TiO2/SiO2 under UV-irradiation.

    Science.gov (United States)

    Miao, Guang; Ye, Feiyan; Wu, Luoming; Ren, Xiaoling; Xiao, Jing; Li, Zhong; Wang, Haihui

    2015-12-30

    This study investigates selective adsorption of thiophenic compounds from fuel over TiO2/SiO2 under UV-irradiation. The TiO2/SiO2 adsorbents were prepared and then characterized by N2 adsorption, X-ray diffraction and X-ray photoelectron spectroscopy. Adsorption isotherms, selectivity and kinetics of TiO2/SiO2 were measured in a UV built-in batch reactor. It was concluded that (a) with the employment of UV-irradiation, high organosulfur uptake of 5.12 mg/g was achieved on the optimized 0.3TiO2/0.7SiO2 adsorbent at low sulfur concentration of 15 ppmw-S, and its adsorption selectivity over naphthalene was up to 325.5; (b) highly dispersed TiO2 served as the photocatalytic sites for DBT oxidation, while SiO2 acted as the selective adsorption sites for the corresponding oxidized DBT using TiO2 as a promoter, the two types of active sites worked cooperatively to achieve the high adsorption selectivity of TiO2/SiO2; (c) The kinetic rate-determining step for the UV photocatalysis-assisted adsorptive desulfurization (PADS) over TiO2/SiO2 was DBT oxidation; (d) consecutive adsorption-regeneration cycles suggested that the 0.3TiO2/0.7SiO2 adsorbent can be regenerated by acetonitrile washing followed with oxidative air treatment. This work demonstrated an effective PADS approach to greatly enhance adsorption capacity and selectivity of thiophenic compounds at low concentrations for deep desulfurization under ambient conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Fabrication of hierarchical structured SiO2/polyetherimide-polyurethane nanofibrous separators with high performance for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhai, Yunyun; Xiao, Ke; Yu, Jianyong; Ding, Bin

    2015-01-01

    Highlights: • Electrospinning followed by dip-coating was used to fabricate SiO 2 /PEI-PU membranes. • Introducing PEI, PU and SiO 2 improved safety, tensile strength and ionic conductivity. • Coating SiO 2 also restrained the micro-shorting and migrated the self-discharge. • SiO 2 /PEI-PU membranes based cell exhibited prominent cycling and rate performance. - ABSTRACT: The performance of lithium ion battery based on electrospun nanofibrous membranes has gained a great deal of attention in the past decades, but the intrinsic low mechanical strength and large pore size of electrospun membranes limit their battery performance. To overcome this limitation, a powerful strategy for designing, fabricating and evaluating silica nanoparticles coated polyetherimide-polyurethane (SiO 2 /PEI-PU) nanofibrous composite membranes is easily developed via electrospinning followed by a dip-coating process. Benefiting from the high porosity, interpenetrating network structure and synergetic effect of PU, PEI and SiO 2 nanoparticles, the as-prepared composite membranes exhibit high ionic conductivity (2.33 mS cm −1 ), robust tensile strength (15.65 MPa) and improved safety (excellent thermal resistance and flame retardant property). Additionally, the as-prepared composite membranes possess relatively narrow pore size distribution with average pore size of 0.58 μm after coating SiO 2 nanoparticles, which plays an important role in hindering the micro-shorting and mitigating self-discharge. Significantly, the SiO 2 /PEI-PU membranes based Li/LiFePO 4 cell exhibits more excellent cycling stability with capacity retention of 98.7% after 50 cycles at 0.2 C rate and better rate capability compared with the Celgard membrane based cell. The results clearly demonstrate that this is a promising separator candidate for next-generation lithium ion batteries, which may represent a significant step toward separators with improved performance

  5. SiO2 Antireflection Coatings Fabricated by Electron-Beam Evaporation for Black Monocrystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Minghua Li

    2014-01-01

    Full Text Available In this work we prepared double-layer antireflection coatings (DARC by using the SiO2/SiNx:H heterostructure design. SiO2 thin films were deposited by electron-beam evaporation on the conventional solar cell with SiNx:H single-layer antireflection coatings (SARC, while to avoid the coverage of SiO2 on the front side busbars, a steel mask was utilized as the shelter. The thickness of the SiNx:H as bottom layer was fixed at 80 nm, and the varied thicknesses of the SiO2 as top layer were 105 nm and 122 nm. The results show that the SiO2/SiNx:H DARC have a much lower reflectance and higher external quantum efficiency (EQE in short wavelengths compared with the SiNx:H SARC. A higher energy conversion efficiency of 17.80% was obtained for solar cells with SiO2 (105 nm/SiNx:H (80 nm DARC, an absolute conversion efficiency increase of 0.32% compared with the conventional single SiNx:H-coated cells.

  6. Synergetic scattering of SiO2 and Ag nanoparticles for light-trapping enhancement in organic bulk heterojunction

    Science.gov (United States)

    Yang, Huan; Ding, Qiuyu; Li, Ben Q.; Jiang, Xinbing; Zhang, Manman

    2018-02-01

    Though noble metal nanoparticles have been explored to enhance the performance of the organic solar cell, effect of dielectric nanoparticles, and coupled effect of dielectric and metal nanoparticles, have rarely been reported, if at all, on organic solar cell. This work reports an experimental study on synergetic scattering of SiO2 and Ag nanoparticles in a bulk organic heterojunction for the broadband light absorption enhancement. The wavelength scale SiO2 particles were arranged as a monolayer on the surface of the solar cell to guide incident light into the active layer and prolong the effective optical length of the entered energy. This is achieved by the excitation of whispering gallery modes in SiO2 nanoparticles and by leaky mode radiation. When small size Ag particles were incorporated into the transport layer of the solar cell, synergetic scattering of SiO2 and Ag nanoparticles is formed by coupling of the whispering gallery mode of closely arranged SiO2 particles atop and collaborative localized surface plasma resonance scattering of Ag nanoparticles dispersed in the transport layer. As a result, the performance of the organic solar cell is greatly enhanced and the short-circuit current density has an improvement of 42.47%. Therefore, the organic solar cell incorporated with SiO2 and Ag particles presents a meaningful strategy to achieve high energy-harvesting performance. [Figure not available: see fulltext.

  7. Raman and optical absorption spectroscopic investigation of Yb-Er codoped phosphate glasses containing SiO2

    Institute of Scientific and Technical Information of China (English)

    Youkuo Chen; Lei Wen; Lili Hu; Wei Chen; Y. Guyot; G. Boulon

    2009-01-01

    Yb-Er codoped Na2O-Al2O3-P2Os-xSiO2 glasses containing 0 鈥? 20 mol% SiO2 were prepared successfully. The addition of SiO2 to the phosphate glass not only lengthens the bond between P5+ and non-bridging oxygen but also reduces the number of P=O bond. In contrast with silicate glass in which there is only four-fold coordinated Si4+, most probably there coexist [SiO4] tetrahedron and [SiO6] octahedron in our glasses. Within the range of 0 鈥? 20 mol% SiO2 addition, the stimulated emission cross-section of Er3+ ion only decreases no more than 10%. The Judd-Ofelt intensity parameters of Er3+, 惟.2 does not change greatly, but 惟74 and 惟6 decrease obviously with increasing SiO2 addition, because the bond between Er + and O2- is more strongly covalently bonded.

  8. Structure-Dependent Spectroscopic Properties of Yb3+-Doped Phosphosilicate Glasses Modified by SiO2

    Directory of Open Access Journals (Sweden)

    Ling Wang

    2017-02-01

    Full Text Available Yb3+-doped phosphate glasses containing different amounts of SiO2 were successfully synthesized by the conventional melt-quenching method. The influence mechanism of SiO2 on the structural and spectroscopic properties was investigated systematically using the micro-Raman technique. It was worth noting that the glass with 26.7 mol % SiO2 possessed the longest fluorescence lifetime (1.51 ms, the highest gain coefficient (1.10 ms·pm2, the maximum Stark splitting manifold of 2F7/2 level (781 cm−1, and the largest scalar crystal-field NJ and Yb3+ asymmetry degree. Micro-Raman spectra revealed that introducing SiO2 promoted the formation of P=O linkages, but broke the P=O linkages when the SiO2 content was greater than 26.7 mol %. Based on the previous 29Si MAS NMR experimental results, these findings further demonstrated that the formation of [SiO6] may significantly affect the formation of P=O linkages, and thus influences the spectroscopic properties of the glass. These results indicate that phosphosilicate glasses may have potential applications as a Yb3+-doped gain medium for solid-state lasers and optical fiber amplifiers.

  9. Structure-Dependent Spectroscopic Properties of Yb3+-Doped Phosphosilicate Glasses Modified by SiO2

    Science.gov (United States)

    Wang, Ling; Zeng, Huidan; Yang, Bin; Ye, Feng; Chen, Jianding; Chen, Guorong; Smith, Andew T.; Sun, Luyi

    2017-01-01

    Yb3+-doped phosphate glasses containing different amounts of SiO2 were successfully synthesized by the conventional melt-quenching method. The influence mechanism of SiO2 on the structural and spectroscopic properties was investigated systematically using the micro-Raman technique. It was worth noting that the glass with 26.7 mol % SiO2 possessed the longest fluorescence lifetime (1.51 ms), the highest gain coefficient (1.10 ms·pm2), the maximum Stark splitting manifold of 2F7/2 level (781 cm−1), and the largest scalar crystal-field NJ and Yb3+ asymmetry degree. Micro-Raman spectra revealed that introducing SiO2 promoted the formation of P=O linkages, but broke the P=O linkages when the SiO2 content was greater than 26.7 mol %. Based on the previous 29Si MAS NMR experimental results, these findings further demonstrated that the formation of [SiO6] may significantly affect the formation of P=O linkages, and thus influences the spectroscopic properties of the glass. These results indicate that phosphosilicate glasses may have potential applications as a Yb3+-doped gain medium for solid-state lasers and optical fiber amplifiers. PMID:28772601

  10. Realization of Colored Multicrystalline Silicon Solar Cells with SiO2/SiNx:H Double Layer Antireflection Coatings

    Directory of Open Access Journals (Sweden)

    Minghua Li

    2013-01-01

    Full Text Available We presented a method to use SiO2/SiNx:H double layer antireflection coatings (DARC on acid textures to fabricate colored multicrystalline silicon (mc-Si solar cells. Firstly, we modeled the perceived colors and short-circuit current density (Jsc as a function of SiNx:H thickness for single layer SiNx:H, and as a function of SiO2 thickness for the case of SiO2/SiNx:H (DARC with fixed SiNx:H (refractive index n=2.1 at 633 nm, and thickness = 80 nm. The simulation results show that it is possible to achieve various colors by adjusting the thickness of SiO2 to avoid significant optical losses. Therefore, we carried out the experiments by using electron beam (e-beam evaporation to deposit a layer of SiO2 over the standard SiNx:H for 156×156 mm2 mc-Si solar cells which were fabricated by a conventional process. Semisphere reflectivity over 300 nm to 1100 nm and I-V measurements were performed for grey yellow, purple, deep blue, and green cells. The efficiency of colored SiO2/SiNx:H DARC cells is comparable to that of standard SiNx:H light blue cells, which shows the potential of colored cells in industrial applications.

  11. High ink absorption performance of inkjet printing based on SiO2@Al13 core-shell composites

    Science.gov (United States)

    Chen, YiFan; Jiang, Bo; Liu, Li; Du, Yunzhe; Zhang, Tong; Zhao, LiWei; Huang, YuDong

    2018-04-01

    The increasing growth of the inkjet market makes the inkjet printing more necessary. A composite material based on core-shell structure has been developed and applied to prepare inkjet printing layer. In this contribution, the ink printing record layers based on SiO2@Al13 core-shell composite was elaborated. The prepared core-shell composite materials were characterized by X-ray photoelectron spectroscopy (XPS), zeta potential, X-ray diffraction (XRD), scanning electron microscopy (SEM). The results proved the presence of electrostatic adsorption between SiO2 molecules and Al13 molecules with the formation of the well-dispersed system. In addition, based on the adsorption and the liquid permeability analysis, SiO2@Al13 ink printing record layer achieved a relatively high ink uptake (2.5 gmm-1) and permeability (87%), respectively. The smoothness and glossiness of SiO2@Al13 record layers were higher than SiO2 record layers. The core-shell structure facilitated the dispersion of the silica, thereby improved its ink absorption performance and made the clear printed image. Thus, the proposed procedure based on SiO2@Al13 core-shell structure of dye particles could be applied as a promising strategy for inkjet printing.

  12. THE THERMODYNAMIC PROPERTIES OF MELTS OF DOUBLE SYSTEM MgO – Al2O3, MgO – SiO2, MgO – CaF2, Al2O3 – SiO2, Al2O3 – CaF2, SiO2 – CaF2

    Directory of Open Access Journals (Sweden)

    В. Судавцова

    2012-04-01

    Full Text Available Methodology of prognostication of thermodynamics properties of melts is presented from the coordinatesof liquidus of diagram of the state in area of equilibria a hard component is solution, on which energies ofmixing of Gibbs are expected in the double border systems of MgO – Al2O3, MgO – SiO2, MgO – CaF2,Al2O3 – SiO2, Al2O3 - CaF2, SiO2 - CaF2. For the areas of equilibrium there is quasibinary connection(MgAl2O4, Mg2SiO4, Al6Si2O13 – a grout at calculations was used equalization of Hauffe-Wagner. Theobtained data comport with literary

  13. Structure of Mg2SiO4 glass up to 140 GPa

    Science.gov (United States)

    Prescher, C.; Prakapenka, V.; Wang, Y.; Skinner, L. B.

    2014-12-01

    The physical properties of melts at temperature and pressure conditions of the Earth's mantle have a fundamental influence on the chemical and thermal evolution of the Earth. However, direct investigations of melt structures at these conditions are experimentally very difficult or even impossible with current capabilities. In order to still be able to obtain an estimate of the structural behavior of melts at high pressures and temperatures, amorphous materials have been widely used as analogue materials. In particular the investigation of sound wave velocities of amorphous SiO2 and MgSiO3 as analogues for silicate melts indicate structural changes at about ~30-40 GPa and ~130-140 GPa [1]. The transition pressures are lower for MgSiO3 than for SiO2 indicating that these transitions are affected by the degree of polymerization of the SiO2 network of the glasses. Nevertheless, these measurements only give a hint about the occurrence of structural transitions but lack information on the actual structural changes accompanied by the sound wave velocity discontinuities. The pressure of the second structural transition at ~130-140 GPa is of vital importance for geophysics. If it causes silicate melts to become denser than the surrounding solid material, it would result in negatively buoyant melts close to the core-mantle boundary, which could be a major factor affecting the chemical stratification of the Earth's mantle during an early magma ocean after the moon forming impact. In order to resolve the structural transition and estimate the effect of a different degree of polymerization further, we studied the structural behavior of Mg2SiO4 glass up to 140 GPa using X-ray total scattering and pair distribution function analysis. The measurements were performed at the GSECARS 13-IDD beamline at the APS employing the newly developed multichannel collimator (MCC) setup. The MCC effectively removes unwanted Compton scattering of the diamond anvils and enables easy extraction of

  14. Demand and supply in Russian gas market

    International Nuclear Information System (INIS)

    Milovidov, K.N.

    1997-01-01

    The big volume of gas supplies for current and future energy and natural gas balances in Russia is important to understand the likely future dynamics of demand for gas. The path of future demand in Russia is uncertain and the range of possible scenarios is wide. For creating the new gas consumption structure, more deep diversification and development of the gas distribution systems, large investments and considerable periods of time are necessary. The factors usually studied in detail in the conditions of market economy can not be used here as a basis for strategic planning due to several reasons. (R.P.)

  15. Treatment of Gas

    Science.gov (United States)

    ... Funding IFFGD Symposium reports Industry Council Contact Us Treatment of Gas You are here: Home Symptoms & Causes Intestinal Gas ... Controlling Intestinal Gas Foods That May Cause Gas Treatment of Gas Tips on Controlling Gas Adapted from IFFGD Publication # ...

  16. Asian gas

    International Nuclear Information System (INIS)

    Masuda, T.

    1990-01-01

    This paper reports on natural gas which now appears ready to take a leading role on the world energy stage. Demand for natural gas, and specifically LNG, will be strong throughout the world, particularly in Asia. Indonesia and Malaysia will become much more dependent on natural gas in the Asian market. In Thailand, where remarkable economic growth has been fueled by imported oil and domestically produced natural gas, LNG may soon have to be imported from neighboring countries. The author sees Thailand's imports of natural gas increasing from 1.5 to 4.5 million tons annually. Similarly, Korea's imports of LNG will rise from 2 to 8 million tons between 1987 and 2000. In Japan, energy demand is expected to increase at an even faster rate in the 1990s. Given the opposition to nuclear power generation and growing concern about the greenhouse effect, it is likely that LNG will satisfy a major portion of Japan's increasing demand for energy. Japanese gas companies are studying the possibility of establishing a national pipeline network to move gas beyond metropolitan areas

  17. Gas dusulfurization

    International Nuclear Information System (INIS)

    Powell, B.E.; Bakhshi, V.S.; Randolph, D.A.

    1984-01-01

    A process for adsorbing sulfur dioxide from a gas comprising contacting a gas containing SO 2 , such as a flue gas, with about stoichiometric amounts of a specially prepared calcium oxide so that substantially all of the sulfur dioxide content is reacted throughout the calcium oxide particle to form a calcium sulfate reaction product. The useful calcium oxide particles comprise a highly voided skeletal structure of very large surface area and large pore volume with numerous macro pores. Such particles are obtained by flash calcining sand-size grains of calcium carbonate, such as aragonite, calcite or dolomite

  18. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  19. In-situ grown CNTs modified SiO2/C composites as anode with improved cycling stability and rate capability for lithium storage

    Science.gov (United States)

    Wang, Siqi; Zhao, Naiqin; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; He, Fang; Ma, Liying

    2018-03-01

    Silica (SiO2) is regarded as one of the most promising anode materials for lithium ion batteries owing to its high theoretical specific capacity, relatively low operation potentials, abundance, environmental benignity and low cost. However, the low intrinsic electrical conductivity and large volume change of SiO2 during the discharge/charge cycles usually results in poor electrochemical performance. In this work, carbon nanotubes (CNTs) modified SiO2/C composites have been fabricated through an in-situ chemical vapor deposition method. The results show that the electrical conductivity of the SiO2/C/CNTs is visibly enhanced through a robust connection between the CNTs and SiO2/C particles. Compared with the pristine SiO2 and SiO2/C composites, the SiO2/C/CNTs composites display a high initial capacity of 1267.2 mA h g-1. Besides, an excellent cycling stability with the capacity of 315.7 mA h g-1 is achieved after 1000th cycles at a rate of 1 A g-1. The significantly improved electrochemical properties of the SiO2/C/CNTs composites are mainly attributed to the formation of three dimensional CNT networks in the SiO2/C substrate, which can not only shorten the Li-ion diffusion path but also relieve the volume change during the lithium-ion insertion/extraction processes.

  20. Deposition of O atomic layers on Si(100) substrates for epitaxial Si-O superlattices: investigation of the surface chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Jayachandran, Suseendran, E-mail: suseendran.jayachandran@imec.be [KU Leuven, Department of Metallurgy and Materials, Castle Arenberg 44, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Delabie, Annelies; Billen, Arne [KU Leuven, Department of Chemistry, Celestijnenlaan 200F, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Dekkers, Harold; Douhard, Bastien; Conard, Thierry; Meersschaut, Johan; Caymax, Matty [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Vandervorst, Wilfried [KU Leuven, Department of Physics and Astronomy, Celestijnenlaan 200D, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Heyns, Marc [KU Leuven, Department of Metallurgy and Materials, Castle Arenberg 44, B-3001 Leuven (Belgium); IMEC, Kapeldreef 75, 3001 Leuven (Belgium)

    2015-01-01

    Highlights: • Atomic layer is deposited by O{sub 3} chemisorption reaction on H-terminated Si(100). • O-content has critical impact on the epitaxial thickness of the above-deposited Si. • Oxygen atoms at dimer/back bond configurations enable epitaxial Si on O atomic layer. • Oxygen atoms at hydroxyl and more back bonds, disable epitaxial Si on O atomic layer. - Abstract: Epitaxial Si-O superlattices consist of alternating periods of crystalline Si layers and atomic layers of oxygen (O) with interesting electronic and optical properties. To understand the fundamentals of Si epitaxy on O atomic layers, we investigate the O surface species that can allow epitaxial Si chemical vapor deposition using silane. The surface reaction of ozone on H-terminated Si(100) is used for the O deposition. The oxygen content is controlled precisely at and near the atomic layer level and has a critical impact on the subsequent Si deposition. There exists only a small window of O-contents, i.e. 0.7–0.9 atomic layers, for which the epitaxial deposition of Si can be realized. At these low O-contents, the O atoms are incorporated in the Si-Si dimers or back bonds (-OSiH), with the surface Si atoms mainly in the 1+ oxidation state, as indicated by infrared spectroscopy. This surface enables epitaxial seeding of Si. For O-contents higher than one atomic layer, the additional O atoms are incorporated in the Si-Si back bonds as well as in the Si-H bonds, where hydroxyl groups (-Si-OH) are created. In this case, the Si deposition thereon becomes completely amorphous.

  1. Controlling the energy transfer via multi luminescent centers to achieve white light/tunable emissions in a single-phased X2-type Y2SiO5:Eu(3+),Bi(3+) phosphor for ultraviolet converted LEDs.

    Science.gov (United States)

    Kang, Fengwen; Zhang, Yi; Peng, Mingying

    2015-02-16

    So far, more than 1000 UV converted phosphors have been reported for potential application in white light-emitting diodes (WLEDs), but most of them (e.g., Y2O2S:Eu, YAG:Ce or CaAlSiN3:Eu) suffer from intrinsic problems such as thermal instability, color aging or re-absorption by commixed phosphors in the coating of the devices. In this case, it becomes significant to search a single-phased phosphor, which can efficiently convert UV light to white lights. Herein, we report a promising candidate of a white light emitting X2-type Y2SiO5:Eu(3+),Bi(3+) phosphor, which can be excitable by UV light and address the problems mentioned above. Single Bi(3+)-doped X2-type Y2SiO5 exhibits three discernible emission peaks at ∼355, ∼408, and ∼504 nm, respectively, upon UV excitation due to three types of bismuth emission centers, and their relative intensity depends tightly on the incident excitation wavelength. In this regard, proper selection of excitation wavelength can lead to tunable emissions of Y2SiO5:Bi(3+) between blue and green, which is partially due to the energy transfer among the Bi centers. As a red emission center Eu(3+) is codoped into Y2SiO5:Bi(3+), energy transfer has been confirmed happening from Bi(3+) to Eu(3+) via an electric dipole-dipole (d-d) interaction. Our experiments reveal that it is easily realizable to create the white or tunable emissions by adjusting the Eu(3+) content and the excitation schemes. Moreover, a single-phased white light emission phosphor, X2-type Y1.998SiO5:0.01Eu(3+),0.01 Bi(3+), has been achieved with excellent resistance against thermal quenching and a QE of 78%. At 200 °C, it preserves >90% emission intensity of that at 25 °C. Consequent three time yoyo experiments of heating-cooling prove no occurrence of thermal degradation. A WLED lamp has been successfully fabricated with a CIE chromaticity coordinate (0.3702, 0.2933), color temperature 4756 K, and color rendering index of 65 by applying the phosphor onto a UV LED

  2. Values must be created before they are shared. Social perspectives

    International Nuclear Information System (INIS)

    Lind, Even; Eriksen, Lise Haaland

    2004-01-01

    The petroleum industry in Norway is a high-tech locomotive with spin-offs and ripple effects that affect the entire nation. The oil and gas industry is the country's largest source of income. Thanks to its oil and natural gas, Norway has become a rich country, both in terms of money and knowledge. Oil production on the Norwegian Shelf peaked in the summer of 2000 and is now declining. We do not explore as much as we used to, and the activity level is falling. As a professional body and employer's organization for oil companies and supplier firms, one of OLF's most important tasks is to help ensure that the Norwegian Shelf is an attractive area for investment and activities. The industry needs larger exploration areas and competitive framework conditions. Fiscal changes have been proposed that will make it more profitable for the industry to increase exploration activities, while also making it more economical to extract oil and gas from the smaller fields. Measures must be implemented to stimulate more activity and good exploitation of the oil and gas resources in the years to come. On this basis, OLF has commissioned a report on social perspectives concerning the oil and gas activities. The social perspectives report addresses the significance of the petroleum industry for industrial and welfare development in Norway, exploration areas and access to resources, safety, technology and expertise, as well as environmental challenges and coexistence among marine industries. Values must be created before they can be shared. If we are to ensure a high level of welfare for generations yet to come, it is essential that the oil and gas activities last as long as possible (author) (ml)

  3. Values must be created before they are shared. Social perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Even; Eriksen, Lise Haaland

    2004-01-15

    The petroleum industry in Norway is a high-tech locomotive with spin-offs and ripple effects that affect the entire nation. The oil and gas industry is the country's largest source of income. Thanks to its oil and natural gas, Norway has become a rich country, both in terms of money and knowledge. Oil production on the Norwegian Shelf peaked in the summer of 2000 and is now declining. We do not explore as much as we used to, and the activity level is falling. As a professional body and employer's organization for oil companies and supplier firms, one of OLF's most important tasks is to help ensure that the Norwegian Shelf is an attractive area for investment and activities. The industry needs larger exploration areas and competitive framework conditions. Fiscal changes have been proposed that will make it more profitable for the industry to increase exploration activities, while also making it more economical to extract oil and gas from the smaller fields. Measures must be implemented to stimulate more activity and good exploitation of the oil and gas resources in the years to come. On this basis, OLF has commissioned a report on social perspectives concerning the oil and gas activities. The social perspectives report addresses the significance of the petroleum industry for industrial and welfare development in Norway, exploration areas and access to resources, safety, technology and expertise, as well as environmental challenges and coexistence among marine industries. Values must be created before they can be shared. If we are to ensure a high level of welfare for generations yet to come, it is essential that the oil and gas activities last as long as possible (author) (ml)

  4. Volcanic Gas

    Science.gov (United States)

    ... offensive odor. It is sometimes referred to as sewer gas. Interestingly, the human nose is more sensitive ... the atmosphere where they can potentially cause acid rain. In an ash -producing eruption, ash particles are ...

  5. Gas - flatulence

    Science.gov (United States)

    ... Gas and other symptoms such as stomach pain, rectal pain, heartburn, nausea, vomiting, diarrhea, constipation, fever, or ... Copyright 1997-2018, A.D.A.M., Inc. Duplication for commercial use must be authorized in writing ...

  6. Gas sensor

    International Nuclear Information System (INIS)

    Dorogan, V.; Korotchenkov, Gh.; Vieru, T.; Prodan, I.

    2003-01-01

    The invention relates to the gas sensors on base of metal-oxide films (SnO, InO), which may be used for enviromental control, in the fireextinguishing systema etc. The gas includes an insulating substrate, an active layer, a resistive layer with ohmic contacts. The resistive layer has two or more regions with dofferent resistances , and on the active layer are two or more pairs of ohmic contacts

  7. GAS STORAGE TECHNOLOGY CONSORTIUM

    Energy Technology Data Exchange (ETDEWEB)

    Robert W. Watson

    2004-10-18

    Gas storage is a critical element in the natural gas industry. Producers, transmission and distribution companies, marketers, and end users all benefit directly from the load balancing function of storage. The unbundling process has fundamentally changed the way storage is used and valued. As an unbundled service, the value of storage is being recovered at rates that reflect its value. Moreover, the marketplace has differentiated between various types of storage services, and has increasingly rewarded flexibility, safety, and reliability. The size of the natural gas market has increased and is projected to continue to increase towards 30 trillion cubic feet (TCF) over the next 10 to 15 years. Much of this increase is projected to come from electric generation, particularly peaking units. Gas storage, particularly the flexible services that are most suited to electric loads, is critical in meeting the needs of these new markets. In order to address the gas storage needs of the natural gas industry, an industry-driven consortium was created--the Gas Storage Technology Consortium (GSTC). The objective of the GSTC is to provide a means to accomplish industry-driven research and development designed to enhance operational flexibility and deliverability of the Nation's gas storage system, and provide a cost effective, safe, and reliable supply of natural gas to meet domestic demand. To accomplish this objective, the project is divided into three phases that are managed and directed by the GSTC Coordinator. The first phase, Phase 1A, was initiated on September 30, 2003, and was completed on March 31, 2004. Phase 1A of the project included the creation of the GSTC structure, development and refinement of a technical approach (work plan) for deliverability enhancement and reservoir management. This report deals with Phase 1B and encompasses the period July 1, 2004, through September 30, 2004. During this time period there were three main activities. First was the

  8. The strongly coupled quark-gluon plasma created at RHIC

    CERN Document Server

    Heinz, Ulrich W

    2009-01-01

    The Relativistic Heavy Ion Collider (RHIC) was built to re-create and study in the laboratory the extremely hot and dense matter that filled our entire universe during its first few microseconds. Its operation since June 2000 has been extremely successful, and the four large RHIC experiments have produced an impressive body of data which indeed provide compelling evidence for the formation of thermally equilibrated matter at unprecedented temperatures and energy densities -- a "quark-gluon plasma (QGP)". A surprise has been the discovery that this plasma behaves like an almost perfect fluid, with extremely low viscosity. Theorists had expected a weakly interacting gas of quarks and gluons, but instead we seem to have created a strongly coupled plasma liquid. The experimental evidence strongly relies on a feature called "elliptic flow" in off-central collisions, with additional support from other observations. This article explains how we probe the strongly coupled QGP, describes the ideas and measurements whi...

  9. Tomorrow, gas

    International Nuclear Information System (INIS)

    Icart, Laura; Jean, Pascale; Georget, Cyrille; Schmill, Rafael

    2017-01-01

    This document contains 12 articles notably addressing the importance of natural gas production and supplies in Europe. The themes of the articles are: the advantages of natural gas in the context of energy and environmental policies, energy diversification, energy supply in the local territories, etc.; the position of GrDF, one of the main French natural gas supplier; LPG (butane, propane), a solution which popularity grows in remote areas; the Gaya project (production of renewable gas from dry biomass); a panorama of gas supply routes in Europe; the situation of gas in Europe's energy supply and consumption; the promotion of LNG fuel for maritime and fluvial ships; why the small scale LNG could be the next revolution; presentation of the new 'Honfleur' ferry (using LNG fuel) that will cross the English Channel by 2019; carbon market and the role of ETS for the energy policy in Europe facing the climatic change challenge; presentation of the French 'Climate Plan' that aims to engage France into a carbon neutrality by 2050; presentation of the French policy against air pollution; economic growth, energy, climate: how to square this circle?

  10. Gas production strategy of underground coal gasification based on multiple gas sources.

    Science.gov (United States)

    Tianhong, Duan; Zuotang, Wang; Limin, Zhou; Dongdong, Li

    2014-01-01

    To lower stability requirement of gas production in UCG (underground coal gasification), create better space and opportunities of development for UCG, an emerging sunrise industry, in its initial stage, and reduce the emission of blast furnace gas, converter gas, and coke oven gas, this paper, for the first time, puts forward a new mode of utilization of multiple gas sources mainly including ground gasifier gas, UCG gas, blast furnace gas, converter gas, and coke oven gas and the new mode was demonstrated by field tests. According to the field tests, the existing power generation technology can fully adapt to situation of high hydrogen, low calorific value, and gas output fluctuation in the gas production in UCG in multiple-gas-sources power generation; there are large fluctuations and air can serve as a gasifying agent; the gas production of UCG in the mode of both power and methanol based on multiple gas sources has a strict requirement for stability. It was demonstrated by the field tests that the fluctuations in gas production in UCG can be well monitored through a quality control chart method.

  11. Gas Production Strategy of Underground Coal Gasification Based on Multiple Gas Sources

    Directory of Open Access Journals (Sweden)

    Duan Tianhong

    2014-01-01

    Full Text Available To lower stability requirement of gas production in UCG (underground coal gasification, create better space and opportunities of development for UCG, an emerging sunrise industry, in its initial stage, and reduce the emission of blast furnace gas, converter gas, and coke oven gas, this paper, for the first time, puts forward a new mode of utilization of multiple gas sources mainly including ground gasifier gas, UCG gas, blast furnace gas, converter gas, and coke oven gas and the new mode was demonstrated by field tests. According to the field tests, the existing power generation technology can fully adapt to situation of high hydrogen, low calorific value, and gas output fluctuation in the gas production in UCG in multiple-gas-sources power generation; there are large fluctuations and air can serve as a gasifying agent; the gas production of UCG in the mode of both power and methanol based on multiple gas sources has a strict requirement for stability. It was demonstrated by the field tests that the fluctuations in gas production in UCG can be well monitored through a quality control chart method.

  12. Creation of technological bases of struggle with generation of natural gas hydrates

    International Nuclear Information System (INIS)

    Asadov, M.M.; Alieva, S.A.

    2005-01-01

    Chemical technological access, permitting directed of intensify processes prevention of gas hydrates during motion of the gas-liquid current of natural gas in the borehole cavity of natural gas-borehole cavity have been engineered. Determined technological regimes of gas current conditioning, permitting create nonequilibrium state providing condition for reversible process

  13. Superhydrophobic coatings fabricated with polytetrafluoroethylene and SiO2 nanoparticles by spraying process on carbon steel surfaces

    International Nuclear Information System (INIS)

    Wang, Haibin; Chen, Eryu; Jia, Xianbu; Liang, Lijun; Wang, Qi

    2015-01-01

    Graphical abstract: - Highlights: • The SiO 2 and PTFE NP-filled coatings exhibit excellent superhydrophobicity. • PTFE-filled coatings show denser structures and better liquid resistance than SiO 2 . • Air pocket of Wentzel model explains the difference in the superhydrophobicity. - Abstract: Superhydrophobicity is extensively investigated because of the numerous methods developed for water-repellant interface fabrication. Many suitable functional materials for the production of superhydrophobic surfaces on various substrates are still being explored. In this study, inorganic SiO 2 and organic polytetrafluoroethylene (PTFE) nanoparticles (NPs) are used for a comparative study on the performance of superhydrophobic coating on carbon steel surfaces. The NPs are added to PTFE coating emulsions by physical blending to form coating mixtures. Raw SiO 2 NPs are then hydrophobized using KH-570 and validated by Fourier transform-infrared spectroscopy (FT-IR) and Dynamic Laser Scattering (DLS) grain size analyses. The microstructures of the surfaces are characterized by contact angle (CA) measurements and field emission-scanning electron microscope (FE-SEM) images. The prepared surfaces are subjected to adhesion, hardness, water resistance, and acid/alkali erosion tests. Hydrophobized SiO 2 -filled coating surfaces are found to have better uniformity than raw SiO 2 regardless of their similar maximum static contact angles (SCAs) about 150°. A SCA of 163.1° is obtained on the PTFE NP-filled coating surfaces that have a considerably denser structure than SiO 2 . Thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses reveal that all fabricated surfaces have good thermal stability and tolerate temperatures up to 550 °C. The PTFE NP-filled coating surfaces also exhibit excellent water and acid resistance. A possible mechanism concerning the amount of trapped air is proposed in relation to practical superhydrophobic surface fabrication

  14. Microstructural, thermal, physical and mechanical behavior of the self compacting concrete containing SiO2 nanoparticles

    International Nuclear Information System (INIS)

    Nazari, Ali; Riahi, Shadi

    2010-01-01

    Research highlights: → TiO 2 nanoparticles effects on flexural strength of self compacting concrete. → Physical and microstructural consideration. → Mechanical tests. → Thermal analysis. → Porosimetry. - Abstract: In the present study, flexural strength, thermal properties and microstructure of self compacting concrete with different amount of SiO 2 nanoparticles has been investigated. SiO 2 nanoparticles with the average particle size of 15 nm were partially added to self compacting concrete and various behaviors of the specimens have been measured. The results indicate that SiO 2 nanoparticles are able to improve the flexural strength of self compacting concrete and recover the negative effects of superplasticizer on flexural strength of the specimens. SiO 2 nanoparticle as a partial replacement of cement up to 4 wt% could accelerate C-S-H gel formation as a result of the increased crystalline Ca(OH) 2 amount at the early ages of hydration. The increased the SiO 2 nanoparticles' content more than 4 wt%, causes the reduced the flexural strength because of unsuitable dispersion of nanoparticles in the concrete matrix. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of peaks related to hydrated products in X-ray diffraction results, all also indicate that SiO 2 nanoparticles up to 4 wt% could improve the mechanical and physical properties of the specimens. Finally, SiO 2 nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.

  15. Creating and Viewing HTML Files with Python

    Directory of Open Access Journals (Sweden)

    William J. Turkel

    2012-07-01

    Full Text Available This lesson uses Python to create and view an HTML file. If you write programs that output HTML, you can use any browser to look at your results. This is especially convenient if your program is automatically creating hyperlinks or graphic entities like charts and diagrams. Here you will learn how to create HTML files with Python scripts, and how to use Python to automatically open an HTML file in Firefox.

  16. Creating and Viewing HTML Files with Python

    OpenAIRE

    William J. Turkel; Adam Crymble

    2012-01-01

    This lesson uses Python to create and view an HTML file. If you write programs that output HTML, you can use any browser to look at your results. This is especially convenient if your program is automatically creating hyperlinks or graphic entities like charts and diagrams. Here you will learn how to create HTML files with Python scripts, and how to use Python to automatically open an HTML file in Firefox.

  17. Magnetic SiO2 gel microspheres for arterial embolization hyperthermia

    International Nuclear Information System (INIS)

    Li Zhixia; Kawashita, Masakazu; Araki, Norio; Mitsumori, Michihide; Hiraoka, Masahiro; Doi, Masaaki

    2010-01-01

    We have prepared magnetic SiO 2 microspheres with a diameter of 20-30 μm as thermoseeds for hyperthermia of cancer. These were prepared by directly introducing preformed magnetic iron oxide nanoparticles (IONPs) into microspheres of a SiO 2 gel matrix derived from the hydrolysis of tetramethoxysilane (TMOS) in a water-in-oil (W/O) emulsion. Dimethylformamide (DMF) was used as a stabilizer, methanol (CH 3 OH) as a dispersant and ammonia (NH 4 OH) as the catalyst for the formation of the spherical particles in the aqueous phase of the W/O emulsion. The magnetic IONPs were synthesized hydrochemically in an aqueous system composed of ferrous chloride, sodium nitrate and sodium hydroxide. Mono-dispersed magnetic SiO 2 gel microspheres with a diameter of approximately 20 μm were successfully obtained by adding a determined amount of solution with a molar ratio of TMOS/DMF/CH 3 OH/H 2 O/NH 4 OH = 1:1.4:9:20:0.03 to kerosene with a surfactant (sorbitan monooleate/sorbitan monostearate = 3:1 by weight ratio) that was 30 wt% of the total amount of the oil phase. These were estimated to contain up to 60 wt% of IONPs that consisted mainly of Fe 3 O 4 and showed a higher specific absorption rate (SAR = 27.9-43.8 W g -1 ) than that of the starting IONPs (SAR = 25.3 W g -1 ) under an alternating current magnetic field of 300 Oe and 100 kHz.

  18. Gas war

    International Nuclear Information System (INIS)

    Shiry, J.

    1992-01-01

    The sale of natural gas to California is one of the most complex and contested trade disputes between the USA and Canada. The background and the issues involved are discussed. An oversupply of Canadian gas, combined with USA subsidies for producing coalbed methane and a general oversupply of gas in the USA, have made spot gas prices decline to unexpectedly low levels. California regulators have responded to this situation by trying to secure the lowest possible prices for consumers, thereby causing them to abandon long-standing trade policies with Canada. The main agent of this change is the California Public Utilities Commission (CPUC), whose actions have reduced the value of Canadian exports and Alberta government revenues by at least $250 million annually. CPUC supported buying from a supply pool (Alberta ampersand Southern Gas) since it provided monopoly purchasing power, and CPUC's policy against pipeline expansion produced the limited access to California that the CPUC now cites as evidence of a producer cartel. CPUC has interfered in contracts with Canadian producers in its pipeline access policies, its capacity brokering decision of 1991, and its reasonableness test for past sales. In its haste to force its own view of market results onto existing contractual relationships, the CPUC is not allowing open negotiations to reshape the relationship, and CPUC actions may be generating countermeasures by Alberta that are inappropriate under deregulation. 3 figs

  19. Gas attack

    Energy Technology Data Exchange (ETDEWEB)

    North, D.

    1977-08-01

    Consumersfirst Ltd. is reacting to deregulation with a massive advertising campaign. The gas utility is owned by Consumers Gas Energy Inc., and is struggling to hold onto its 35 per cent share of Ontario`s two million residential natural gas buyers. An industry analyst pointed out that deregulation could mean that Consumers` Gas has much to lose: customers, market share, control of the assets and control of the process. The Ontario Energy Board (OEB) however, had specified that Consumersfirst is not to proceed with paperwork to sign up new customers until the OEB issues a draft code-of-conduct that would prevent cross-subsidizing between regulated franchise holders. This has now been done, and several heavyweights such as Calgary-based Suncor Energy Inc., Union Gas of Chatham, Ontario, and the US-based Enron Corp. of Houston, have started campaigns to sign up potential consumers. It is predicted that brand loyalty will be a factor, but in the end, like long distance telephone rates, it will all come down to pricing, and a winning formula is not easy to find.

  20. SiO2-supported Pt particles studied by electron microscopy

    International Nuclear Information System (INIS)

    Wang, D.; Penner, S.; Su, D.S.; Rupprechter, G.; Hayek, K.; Schloegl, R.

    2003-01-01

    Regularly grown Pt particles supported by amorphous SiO 2 were heated in hydrogen at 873 K after an oxidising treatment. The morphological and structural changes were studied by electron microscopy. Platinum silicides Pt 3 Si with L1 2 (Cu 3 Au) structure, monoclinic Pt 3 Si and tetragonal Pt 12 Si 5 were identified after the treatment. The mechanisms of coalescence of the particles and the formation of irregular large particles are suggested. A topotactic structural transformation accompanied with the migration of Si from the substrate to the particles are suggested to take place during Pt 3 Si formation

  1. Space growth studies of Ce-doped Bi12SiO20 single crystal

    International Nuclear Information System (INIS)

    Zhou, Y.F.; Wang, J.C.; Tang, L.A.; Pan, Z.L.; Chen, N.F.; Chen, W.C.; Huang, Y.Y.; He, W.

    2004-01-01

    Ce-doped Bi 12 SiO 20 (BSO) single crystal was grown on board of the Chinese Spacecraft-Shenzhou No. 3. A cylindrical crystal, 10 mm in diameter and 40 mm in length, was obtained. The morphology of crystals is significantly different for ground- and space-grown portions. The space- and ground-grown crystals have been characterized by Ce concentration distribution, X-ray rocking curve absorption spectrum and micro-Raman spectrum. The results show that the quality of Ce-doped BSO crystal grown in space is more homogeneous and more perfect than that of ground grown one

  2. Disordered electrical potential observed on the surface of SiO2 by electric field microscopy

    International Nuclear Information System (INIS)

    GarcIa, N; Yan Zang; Ballestar, A; Barzola-Quiquia, J; Bern, F; Esquinazi, P

    2010-01-01

    The electrical potential on the surface of ∼300 nm thick SiO 2 grown on single-crystalline Si substrates has been characterized at ambient conditions using electric field microscopy. Our results show an inhomogeneous potential distribution with fluctuations up to ∼0.4 V within regions of 1 μm. The potential fluctuations observed at the surface of these usual dielectric holders of graphene sheets should induce strong variations in the graphene charge densities and provide a simple explanation for some of the anomalous behaviors of the transport properties of graphene.

  3. Friction and wear properties of ZrO2/SiO2 composite nanoparticles

    International Nuclear Information System (INIS)

    Li Wei; Zheng Shaohua; Cao Bingqiang; Ma Shiyu

    2011-01-01

    In this article, the lubrication properties of ZrO 2 /SiO 2 composite nanoparticles modified with aluminum zirconium coupling agent as additives in lubricating oil under variable applied load and concentration fraction were reported. It was demonstrated that the modified nanoparticles as additives in lubrication can effectively improve the lubricating properties. Under an optimized concentration of 0.1 wt%, the average friction coefficient was reduced by 16.24%. This was because the nanoparticles go into the friction zone with the flow of lubricant, and then the sliding friction changed to rolling friction with a result of the reduction of the friction coefficient.

  4. Hydrogen and chlorine detection at the SiO2/Si interface

    International Nuclear Information System (INIS)

    Tsong, I.S.T.; Monkowski, M.D.; Monkowski, J.R.; Wintenberg, A.L.; Miller, P.D.; Moak, C.D.

    1981-01-01

    Hydrogen and chlorine depth profiles were obtained on a series of silicon oxides thermally grown in HCl/O 2 and Cl 2 /O 2 ambients at 1100 0 C for 15 minutes using the 19 F nuclear reaction and SIMS techniques. The data show close correlation between the H and Cl profiles in both the HCl/O 2 and Cl 2 /O 2 oxides. While the H and Cl appear to be enriched at the SiO 2 /Si interface of the HCl/O 2 oxides, they are higher in concentration and more evenly distributed in the oxide bulk of the Cl 2 /O 2 oxides

  5. Dielectric strength of SiO2 in a CMOS transistor structure

    International Nuclear Information System (INIS)

    Soden, J.M.

    1979-01-01

    The distribution of experimental dielectric strengths of SiO 2 gate dielectric in a CMOS transistor structure is shown to be composed of a primary, statistically-normal distribution of high dielectric strength and a secondary distribution spread through the lower dielectric strength region. The dielectric strength was not significantly affected by high level (1 x 10 6 RADS (Si)) gamma radiation or high temperature (200 0 C) stress. The primary distribution breakdowns occurred at topographical edges, mainly at the gate/field oxide interface, and the secondary distribution breakdowns occurred at random locations in the central region of the gate

  6. Experimental study of viscosity properties of emulsion system with SiO2 nanoparticles.

    Directory of Open Access Journals (Sweden)

    ZEIGMAN Yury Veniaminovich,

    2017-04-01

    Full Text Available When oil production is increasing due to intensive oilfield development methods supporting seam pressure by water injection oil producers face the problem of displacement agent break in more permeable intervals of petroleum reservoir. That leads to dramatic increase of product inundation for well stock and decrease of economic efficiency for well performance. Nowadays the petroleum engineers have proposed more than 100 technologies designed to restrict water inflows and flooding agent to bottom-hole zone of the production wells. The water inflows restriction technologies are distinguished by the type of applied chemical compositions and the way how the chemical compositions are delivered to bottom-hole zone. The analysis of the currently applied chemical compositions has allowed authors to reveal the common feature. The common feature is that the currently applied chemical compositions are non-selective and they produce isolating or blocking effect onto water-saturated and oil-saturated zones of the petroleum reservoir. The application of the nonselective high-stability chemical compositions leads to uncontrolled colmatation of all treated intervals and makes it difficult to involve them into filtration process in future. This work presents the technology for the selective reservoir stimulation based on emulsion systems with SiO2 nanoparticles content and gelling acid composition. The technology was developed for complex impact on formation system, that achieved by blocking water-saturated intervals of reservoir and stimulation of less permeable oil-saturated intervals of reservoir. The paper shows the results of complex laboratory experiments to study viscosity parameters of emulsion systems with SiO2 nanoparticles content. The results of the experiments revealed the ability of the SiO2 nanoparticles to rise dynamic viscosity of the different type of emulsion systems: oil in water and water in oil. Test for thermostability of the modified

  7. Internal Friction of (SiO2)1-x (GeO2)x Glasses

    OpenAIRE

    Kosugi , T.; Kobayashi , H.; Kogure , Y.

    1996-01-01

    Internal friction of (SiO2)1-x (GeO2)x glasses (x = 0, 5, 10, 24 and 100 mole%) is measured at temperatures between 1.6 and 280 K. The data are filted with the equations for thermally activated relaxation with distributing activation energies in symmetrical double-well potentials. From the determined relaxation strength spectra for each sample, the contributions from each type of microscopic structural units are calculated assuming that transverse motion of the bridging O atom in Si-O-Si, Si-...

  8. Tetrahedral ↔ octahedral network structure transition in simulated vitreous SiO2

    International Nuclear Information System (INIS)

    Vo Van Hoang; Nguyen Trung Hai; Hoang Zung

    2006-01-01

    By using molecular dynamics (MD) simulations we found a transition from a tetrahedral to an octahedral network structure in an amorphous SiO 2 model under compression from 2.20 to 5.35 g/cm 3 . And on heating of a high density amorphous (hda) model of 5.35 g/cm 3 at zero pressure, the structure transforms to a low density amorphous (lda) form. Simulations were done in a model containing 3000 particles under periodic boundary conditions with interatomic potentials which have a weak Coulomb interaction and a Morse type short-range interaction

  9. Ordering at Si(111)/o-Si and Si(111)/SiO2 Interfaces

    DEFF Research Database (Denmark)

    Robinson, I. K.; Waskiewicz, W. K.; Tung, R. T.

    1986-01-01

    X-ray diffraction has been used to measure the intensity profile of the two-dimensional rods of scattering from a single interface buried inside a bulk material. In both Si(111)/a-Si and Si(111)/SiO2 examples there are features in the perpendicular-momentum-transfer dependence which are not expec...... are not expected from an ideal sharp interface. The diffraction profiles are explained by models with partially ordered layers extending into the amorphous region. In the Si(111)/a-Si case there is clear evidence of stacking faults which are attributed to residual 7×7 reconstruction....

  10. Measurement of nanosize etched pits in SiO2 optical fiber conduit using AFM

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Vazquez, C.; Fragoso, R.

    2003-01-01

    Fission fragment tracks from 252 Cf have been observed in SiO 2 optical fiber, using an atomic force microscope (AFM), after a very short chemical etching in hydrofluoric acid solution at normal temperature. The nuclear track starting and evolution process is followed by the AFM direct measurements on the material surface and beyond a fine layer of the surface material. The images of the scanned cones were determined observing the two predominant energies from 252 Cf fission fragments and the development of the tracks in the 150 μm diameter optical fiber conduit

  11. Phase modulation spectroscopy of space-charge wave resonances in Bi12SiO20

    DEFF Research Database (Denmark)

    Vasnetsov, M.; Buchhave, Preben; Lyuksyutov, S.

    1997-01-01

    A new experimental method for the study of resonance effects and space-charge wave excitation in photorefractive Bi12SiO20 crystals by using a combination of frequency detuning and phase modulation technique has been developed. The accuracy of the method allows a detection of resonance peaks...... of diffraction efficiency within 0.5 Hz. Numerical simulations of the nonlinear differential equations describing the behaviour of the space-charge waves in photorefractive crystals have been performed and found to be in a good agreement with experiment. We have measured the photocurrent through the crystal...

  12. Efeitos neurotóxicos de sulfato de magnésio intratecal

    Directory of Open Access Journals (Sweden)

    Levent Ozdogan

    2013-02-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: Avaliar os potenciais efeitos neurotóxicos em nível ultraestrutural desulfato de magnésio administrado por via intratecal em dose única ou múltipla. MÉTODOS: Estudo realizado com 24 ratos Sprague-Dawley, peso médio entre 250 e 300 g. Apósjejum de 4 horas, os ratos receberam 10 mg.kg-1 de cloreto de xilazina por via intraperitoneale, em seguida, foram divididos aleatoriamente em três grupos. Grupo I (n = 8 recebeu 0,9% desoro fisiológico normal, Grupo II (n = 8 recebeu uma injeção de 0,02 mL de sulfato de magnésioa 15% por via intratecal e Grupo III (n = 8 recebeu 0,02 mL de sulfato de magnésio a 15% umavez por dia durante sete dias. As injeções foram aplicadas dentro de 0,40x50 milímetros daárea lombar. Após sete dias, os animais foram sacrificados sob anestesia com uma injeção deformaldeído a 10% na aorta e os tecidos foram fixados. A medula espinal foi, então, examinadae histopatologicamente avaliada sob microscópio eletrônico. O teste de Kruskal-Wallis foi usadopara avaliação estatística. Um valor de p < 0,05 foi considerado estatisticamente significativo. RESULTADOS: Neurodegeneração significativa foi detectada nos ratos que receberam uma únicainjeção ou injeções repetidas de sulfato de magnésio, em comparação com o grupo controle. O escore na avaliação histopatológica desse grupo também foi alto. CONCLUSÃO: Com base no exame de microscopia eletrônica, descobrimos que a administraçãointratecal de sulfato de magnésio induziu neurodegeneração.

  13. Ultrasensitive spectroscopy based on photonic waveguides on Al2O3/SiO2 platform

    Science.gov (United States)

    Heidari, Elham; Xu, Xiaochuan; Tang, Naimei; Mokhtari-Koushyar, Farzad; Dalir, Hamed; Chen, Ray T.

    2018-02-01

    Here a photonic waveguide on Al2O3/SiO2 platform is proposed to cover the 240 320 nm wavelength-range, which is of paramount significance in protein and nuclei acid quantification. Our optical waveguide increases path-length and overlap integration for light-matter interaction with proteins. The proposed system detects one order less proteins concentration as low as 12.5 μg/ml compared with NanoDropTM that detects Beer-Lambert-law.

  14. Positron trap centers in x-ray and γ-ray irradiated SiO2

    International Nuclear Information System (INIS)

    Khatri, R.; Asoka-Kumar, P.; Nielsen, B.; Roellig, L.O.; Lynn, K.G.

    1993-01-01

    Using Doppler broadening annihilation spectroscopy, we investigated the properties of irradiated samples of SiO 2 /Si(100) with 117 nm thick oxide layer, grown in dry O 2 on p- and n-type substrates. These samples were irradiated with γ rays and x rays at doses in the range of 7x10 4 --9x10 6 rad and 50--2000 mJ/cm 2 , respectively. The changes observed in the Doppler broadening line shape parameter after irradiation and its recovery during isochronal annealing were used to obtain an activation energy of 1.48--1.61 eV required for annealing the defects

  15. Examination of Hydrate Formation Methods: Trying to Create Representative Samples

    Energy Technology Data Exchange (ETDEWEB)

    Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.; Kwon, T.-H.

    2011-04-01

    Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlled conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas

  16. The influence of SiO2 Addition on 2MgO-Al2O3-3.3P2O5 Glass

    DEFF Research Database (Denmark)

    Larsen, P.H.; Poulsen, F.W.; Berg, Rolf W.

    1999-01-01

    2MgO-Al2O3-3.3P2O5 glasses with increasing amounts of SiO2 are considered for sealing applications in Solid Oxide Fuel Cells (SOFC). The change in chemical durability under SOFC anode conditions and the linear thermal expansion is measured as functions of the SiO2 concentration. Raman spectroscopy...... analysis of the glasses reveals no sign of important changes in the glass structure upon SiO2 addition. Some increase in glass durability with SiO2 concentration is reported and its cause is discussed....

  17. Potentiodynamical deposition of nanostructured MnO2 film at the assist of electrodeposited SiO2 as template

    International Nuclear Information System (INIS)

    Wu, Lian-Kui; Xia, Jie; Hou, Guang-Ya; Cao, Hua-Zhen; Tang, Yi-Ping; Zheng, Guo-Qu

    2016-01-01

    Highlights: • MnO 2 -SiO 2 composite film is prepared by potentiodynamical deposition. • Hierarchical porous MnO 2 films is obtained after the etching of SiO 2 . • The obtained MnO 2 film electrode exhibit high specific capacitance. - Abstract: We report a novel silica co-electrodeposition route to prepare nanostructured MnO 2 films. Firstly, MnO 2 -SiO 2 composite film was fabricated on a stainless steel substrate by potentiodynamical deposition, i.e. cyclic deposition, and then the SiO 2 template was removed by simple immersion in concentrated alkaline solution, leading to the formation of a porous MnO 2 (po-MnO 2 ) matrix. The structure and morphology of the obtained films were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the po-MnO 2 film were evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). Results showed that this porous MnO 2 derived from the MnO 2 -SiO 2 composite film exhibits good electrochemical performance for potential use as a supercapacitor material.

  18. Synthesis and Characterization of Ti-Phenyl at SiO2 Core-Shell Nanoparticles Catalyst

    International Nuclear Information System (INIS)

    Syamsi Aini; Jon Efendi; Syamsi Aini; Jon Efendi

    2012-01-01

    This study highlights the potential use of Ti-Phenyl at SiO 2 core-shell nanoparticles as heterogeneous catalysis in oxidation reaction. The Ti-Phenyl at SiO 2 was synthesized by reduction of TiCl 4 and diazonium salt with sodium borohydride to produce phenyl titanium nanoparticles (Ti-Phenyl), followed by the silica shell coating using tetraethyl orthosilicate (TEOS). The Ti-Phenyl at SiO 2 nanoparticles were characterized by Fourier transform infrared (FTIR) spectrometer, diffuse reflectance (DR) UV-visible spectrometer, thermogravimetric analyzer (TGA), X-ray diffraction (XRD) spectrometer, field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The core-shell size of Ti-Phenyl at SiO 2 was in the range of 40 to 100 nm with its core composed with an agglomeration of Ti-Phenyl. The Ti-Phenyl at SiO 2 was active as a catalyst in the liquid phase epoxidation of 1-octene with aqueous hydrogen peroxide as an oxidant. (author)

  19. Effect of SiO2, PVA and glycerol concentrations on chemical and mechanical properties of alginate-based films.

    Science.gov (United States)

    Yang, Manli; Shi, Jinsheng; Xia, Yanzhi

    2018-02-01

    Sodium alginate (SA)/polyvinyl alcohol (PVA)/SiO 2 nanocomposite films were prepared by in situ polymerization through solution casting and solvent evaporation. The effect of different SA/PVA ratios, SiO 2 , and glycerol content on the mechanical properties, water content, water solubility, and water vapor permeability were studied. The nanocomposite films were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermal stability (thermogravimetric analysis/differential thermogravimetry) analyses. The nanocomposites showed the highest values of mechanical properties, such as SA/PVA ratio, SiO 2 , and glycerol content was 7:3, 6wt.%, and 0.25g/g SA, respectively. The tensile strength and elongation at break (E%) of the nanocomposites increased by 525.7% and 90.7%, respectively, compared with those of the pure alginate film. The Fourier transform infrared spectra showed a new SiOC band formed in the SA/PVA/SiO 2 nanocomposite film. The scanning electron microscopy image revealed good adhesion between SiO 2 and SA/PVA matrix. After the incorporation of PVA and SiO 2 , the water resistance of the SA/PVA/SiO 2 nanocomposite film was markedly improved. Transparency decreased with increasing PVA content but was enhanced by adding SiO 2 . Copyright © 2017. Published by Elsevier B.V.

  20. INVESTIGATION ON PHYSICAL AND ELECTRICAL PROPERTIES OF THE SiO2-ZnO NANOCOMPOSITE AT DIFFERENT COMPOSITION MIXINGS

    Directory of Open Access Journals (Sweden)

    Moh. Sinol

    2018-01-01

    Full Text Available Physical and electrical properties of The SiO2-ZnO mixing at different compositions were investigated. The experiment used simple mixing method at the sintering temperature 600oC. It was used the composition mixing ratio of SiO2:ZnO ie. 0:10; 7:3; 5:5; 3:7; and 10:0 (%Wt. Based on X-Ray Diffraction (XRD results, it obtained that a new phase in each sample was not formed even though having different diffraction peak. The mixing ratio of SiO2: ZnO nanocomposite (7:3 %wt had the biggest grain size (77,92 nm, the highest dielectric constant (3.00E+05 and the smallest conductivity (0,726549 (Ωm-1. On the other side, the mixing ratio of SiO2: ZnO nanocomposite (5:5 %wt had the smallest grain size (35.42nm, dielectric constant (3.00E+2 and the highest conductivity (25.36729  (Ωm-1. It can be concluded that the difference of composition ratio offered the change on both physical and electrical properties of SiO2-ZnO nanocomposite.

  1. Liquidus Temperature of SrO-Al2O3-SiO2 Glass-Forming Compositions

    DEFF Research Database (Denmark)

    Abel, Brett M.; Morgan, James M.; Mauro, John C.

    2013-01-01

    . In the composition range of interest for industrial glasses, Tliq tends to decrease with increasing strontium-to-alumina ratio. We find that cristobalite, mullite, and slawsonite are the dominant devitrification phases for the compositions with high SiO2, SiO2+Al2O3, and SrO contents, respectively. By comparison...... with the phase diagrams for CaO-Al2O3-SiO2 and MgO-Al2O3-SiO2 systems, we have found that for the highest [RO]/[Al2O3] ratios, Tliq exhibits a minimum value for R = Ca. Based on the phase diagram established here, the composition of glass materials, for example, for liquid crystal display substrates, belonging...... to the SrO-Al2O3-SiO2 family may be designed with a more exact control of the glass-forming ability by avoiding the regions of high liquidus temperature....

  2. VO x /SiO 2 Catalyst Prepared by Grafting VOCl 3 on Silica for Oxidative Dehydrogenation of Propane

    KAUST Repository

    Zhu, Haibo; Ould-Chikh, Samy; Dong, Hailin; Llorens, Isabelle; Saih, Youssef; Anjum, Dalaver H.; Hazemann, Jean Louis; Basset, Jean-Marie

    2015-01-01

    The VOx/SiO2 catalysts for oxidative dehydrogenation of propane were synthesized by a simple grafting method. The VOCl3 was first grafted at the surface of SiO2, which was dehydrated at different temperature (from 200 to 1000°C). The formed grafted complexes were then calcined in air, leading to the formation of VOx/SiO2 catalysts. The synthesized catalysts were characterized by nitrogen adsorption, SEM, Raman spectroscopy, temperature-programmed reduction, and extended X-ray absorption fine structure analysis. The SiO2 pretreatment temperature has an evident effect on the loading and dispersion of VOx on SiO2, which finally affects their catalytic performance. High SiO2 treatment temperature is beneficial to dispersing the vanadium oxide species at the SiO2 surface. These materials are efficient catalysts for the catalytic oxidative dehydrogenation of propane to propylene. The best selectivity to propylene is achieved on the VOx/SiO2-(1000) catalyst. The high selectivity and activity are well maintained for three days catalytic reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Passivation of pigment-grade TiO2 particles by nanothick atomic layer deposited SiO2 films

    International Nuclear Information System (INIS)

    King, David M; Liang Xinhua; Weimer, Alan W; Burton, Beau B; Akhtar, M Kamal

    2008-01-01

    Pigment-grade TiO 2 particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO 2 and Al 2 O 3 layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO 2 films were deposited using tris-dimethylaminosilane (TDMAS) and H 2 O 2 at 500 deg. C. Trimethylaluminum and water were used as precursors for Al 2 O 3 ALD at 177 deg. C. The photocatalytic activity of anatase pigment-grade TiO 2 was decreased by 98% after the deposition of 2 nm SiO 2 films. H 2 SO 4 digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO 2 digest rate was 40 times faster for uncoated TiO 2 than SiO 2 coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H 2 O 2 chemistry can deposit high quality, fully dense SiO 2 films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO 2 particles

  4. Excellent Brightness with Shortening Lifetime of Textured Zn2SiO4:Mn2+ Phosphor Films on Quartz Glass

    Science.gov (United States)

    Park, Jehong; Park, Kwangwon; Lee, Jaebum; Kim, Jongsu; Kim, Seongsin Margaret; Kung, Patrick

    2010-04-01

    Green-emissive textured Zn2SiO4:Mn2+ phosphor films were fabricated by the thermal diffusion of ZnO:Mn on quartz glass. The Zn2SiO4:Mn2+ phosphor films became textured along several hexagonal directions and their chemical composition was continuously graded at the interface. The decay time of Mn2+ was as short as 4.4 ms, and the optical transition probability of the films defined as the inverse of decay time showed a strong correlation with film texture degree as a function of annealing temperature. The brightest Zn2SiO4:Mn2+ film showed a photoluminescent brightness as high as 65% compared with a commercial Zn2SiO4:Mn2+ phosphor powder screen and a maximum absolute transparency of 70%. These excellent optical properties are explained by the combination of the unique textured structure and continuous grading of the Zn2SiO4:Mn2+ chemical composition at the interface.

  5. VO x /SiO 2 Catalyst Prepared by Grafting VOCl 3 on Silica for Oxidative Dehydrogenation of Propane

    KAUST Repository

    Zhu, Haibo

    2015-09-07

    The VOx/SiO2 catalysts for oxidative dehydrogenation of propane were synthesized by a simple grafting method. The VOCl3 was first grafted at the surface of SiO2, which was dehydrated at different temperature (from 200 to 1000°C). The formed grafted complexes were then calcined in air, leading to the formation of VOx/SiO2 catalysts. The synthesized catalysts were characterized by nitrogen adsorption, SEM, Raman spectroscopy, temperature-programmed reduction, and extended X-ray absorption fine structure analysis. The SiO2 pretreatment temperature has an evident effect on the loading and dispersion of VOx on SiO2, which finally affects their catalytic performance. High SiO2 treatment temperature is beneficial to dispersing the vanadium oxide species at the SiO2 surface. These materials are efficient catalysts for the catalytic oxidative dehydrogenation of propane to propylene. The best selectivity to propylene is achieved on the VOx/SiO2-(1000) catalyst. The high selectivity and activity are well maintained for three days catalytic reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. The Effect of Zeolite Composition and Grain Size on Gas Sensing Properties of SnO2/Zeolite Sensor

    Directory of Open Access Journals (Sweden)

    Yanhui Sun

    2018-01-01

    Full Text Available In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO2/Al2O3 ratio, different particle size of MFI type zeolites (ZSM-5 were coated on the SnO2 to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO2/Al2O3 = 70, grain size 300 nm coated SnO2 gas sensors to formaldehyde vapor were increased, and the response to acetone decreased compared with that of SnO2 gas sensor, indicating an improved selectivity property. The other three ZSM-5 zeolites with SiO2/Al2O3 70, 150 and 470, respectively, and grain sizes all around 1 μm coated SnO2 sensors did not show much difference with SnO2 sensor for the response properties to both formaldehyde and acetone. The sensing mechanism of ZSM-5 modified sensors was briefly analyzed.

  7. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    , not all of them are white like snow. Some hydrates from the deep Gulf of Mexico are richly colored in shades of yellow, orange, or even red. The ice-like masses are beautiful, and contrast with the dull gray of deep sea muds. Hydrates from the Blake... volcanoes and associated gas hydrates: Marine Geology, v. 167, p. 29-42. Milkov, A.V. and R. Sassen, 2001a, Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope: Marine Geology, v. 179, pp. 71-83. Milkov, A.V., Sassen, R...

  8. Creating a climate and culture for sustainable organizational change

    Directory of Open Access Journals (Sweden)

    Mahsa Zolghadr

    2016-11-01

    Full Text Available The objective of this research is to investigate the balance between employees’ organizational behavior and the method of managers’ decision making in creating a good organizational climate in Gas Company of Zanjan province, Iran. The statistical population of this research includes 180 professions, staffs, and managers of the company and the study selects 120 people according to random sampling and by the use of Cochran formula. The descriptive-survey research method is cross sectional type. The questionnaire made by researcher was used for data gathering and its reliability and validity was approved. SPSS software was used for data analysis, correlation test was used for the effectiveness, and the effectiveness was specified. Also, LISREL software has been used for performing structural equations of model. The results of the research state that the variables of the balance between organizational behavior of staffs such as the balance of management commitment, balance of leadership, balance of communications, balance of learning, and balance of motivation were effective on its effectiveness in creating good organizational climate in the Gas Company of Zanjan province by managers’ decision making methods.

  9. Optical properties of ZrO2, SiO2 and TiO2-SiO2 xerogels and coatings doped with Eu3+ and Eu2+

    Directory of Open Access Journals (Sweden)

    Gonçalves Rogéria R.

    1999-01-01

    Full Text Available Eu3+ doped bulk monoliths and thin films were obtained by sol-gel methods in the ZrO2, SiO2 and SiO2-TiO2 systems. Eu3+ 5D0 ® 7FJ emission and decay time characteristics were measured during the entire experimental preparation route from the initial sol to the final xerogels. The crystalline phases identified were tetragonal ZrO2 and mixtures of rutile and anatase TiO2 at high temperature treatments in bulk samples. Good quality thin films were obtained for all systems by dip-coating optical glasses (Schott BK270. The same spectroscopic features were observed either for the bulk monoliths or the films. By appropriate heat treatments under H2 atmosphere Eu2+ containing samples could be obtained in the SiO2-TiO2 system.

  10. The 'Shale Gas Revolution'. Hype and Reality

    International Nuclear Information System (INIS)

    Stevens, P.

    2010-09-01

    The 'shale gas revolution' - responsible for a huge increase in unconventional gas production in the US over the last couple of years - is creating huge investor uncertainties for international gas markets and renewables and could result in serious gas shortages in 10 years time. This report casts serious doubt over industry confidence in the 'revolution', questioning whether it can spread beyond the US, or indeed be maintained within it, as environmental concerns, high depletion rates and the fear that US circumstances may be impossible to replicate elsewhere, come to the fore. Investor uncertainty will reduce investment in future gas supplies to lower levels than would have happened had the 'shale gas revolution' not hit the headlines. While the markets will eventually solve this problem, rising gas demand and the long lead-in-times on most gas projects are likely to inflict high prices on consumers in the medium term. The uncertainties created by the 'shale gas revolution' are also likely to compound existing investor uncertainty in renewables for power generation in the aftermath of Copenhagen. The serious possibility of cheap, relatively clean gas may threaten investment in more expensive lower carbon technologies.

  11. Plasma breakdown of low-pressure gas discharges

    NARCIS (Netherlands)

    Wagenaars, E.

    2006-01-01

    Natural gas discharges like lightning and polar light are spectacular phenomena that have impressed and fascinated people for a long time. During the last two centuries, people have learned how to create their own gas discharges and how to make use of them. Nowadays, man-made gas discharges are

  12. Shippers and Network Capacity Booking in the Dutch Gas Market

    NARCIS (Netherlands)

    Bucura, C.; Lukszo, Z.

    2012-01-01

    The main objectives of the Third Gas Directive (2009/73EC) approved by the European Union are: unbundling, creating an independent Transport Service Operator (TSO) and ensuring free access to the market. The separation of gas trading from transportation activities required new market rules and gas

  13. Making sure natural gas gets to market

    International Nuclear Information System (INIS)

    Pleckaitis, A.

    2004-01-01

    The role of natural gas in power generation was discussed with reference to price implications and policy recommendations. New natural gas supply is not keeping pace with demand. Production is leveling out in traditional basins and industry investment is not adequate. In addition, energy deregulation is creating disconnects. This presentation included a map depicting the abundant natural gas reserves across North America. It was noted that at 2002 levels of domestic production, North America has approximately 80 years of natural gas. The AECO consensus wholesale natural gas price forecast is that natural gas prices in 2010 will be lower than today. The use of natural gas for power generation was outlined with reference to fuel switching, distributed generation, and central generation. It was emphasized that government, regulators and the energy industry must work together to address policy gaps and eliminate barriers to new investment. 13 figs

  14. Trans Ocean Gas CNG transportation development plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-11-01

    Liquefied natural gas (LNG) transportation is on the rise due to increased global demand for natural gas. However, the challenge of transporting LNG lies in finding suitable locations for import terminals. Compressed natural gas (CNG) transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets not practical for LNG or pipelines. The founder of Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. Financial support is needed to perform verification testing and for regulatory approval. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. 2 tabs., 3 figs.

  15. Physicochemical characterization of some solid materials by inverse gas chromatography

    International Nuclear Information System (INIS)

    Hamieh, T.; Abdessater, S.

    2004-01-01

    Full text.New equations and models on two-dimensional state of solid surfaces were previously elaborated in many other studies. results obtained were used in this paper to the determination and the quantification of some physicochemical properties of some solid surfaces, and especially, to study the acid-base superficial characteristics of some solid substrates like oxides and/or polymer adsorbed on oxides, carbon fibers, cements, etc. The technique used was the inverse gas chromatography (CGI) at infinite dilution. The acid-base constants were calculated for many solid surfaces: Al 2 O 3 , SiO 2 , MgO, ZnO, some cements, textiles and carbon fibers

  16. Creating Gaze Annotations in Head Mounted Displays

    DEFF Research Database (Denmark)

    Mardanbeigi, Diako; Qvarfordt, Pernilla

    2015-01-01

    To facilitate distributed communication in mobile settings, we developed GazeNote for creating and sharing gaze annotations in head mounted displays (HMDs). With gaze annotations it possible to point out objects of interest within an image and add a verbal description. To create an annota- tion...

  17. Creating Safe Spaces for Music Learning

    Science.gov (United States)

    Hendricks, Karin S.; Smith, Tawnya D.; Stanuch, Jennifer

    2014-01-01

    This article offers a practical model for fostering emotionally safe learning environments that instill in music students a positive sense of self-belief, freedom, and purpose. The authors examine the implications for music educators of creating effective learning environments and present recommendations for creating a safe space for learning,…

  18. Landfill gas management in Canada

    International Nuclear Information System (INIS)

    David, A.

    1997-01-01

    Landfill gas produced from solid waste landfills is one of the most significant sources of anthropogenic methane in Canada. Methane, a potent greenhouse gas, is 24.5 times more powerful than carbon dioxide by weight in terms of global climate change. Landfill gas recovery plays an important role in Canada's commitment to stabilize greenhouse gas emissions at 1990 levels by the year 2000 under the United Nations Framework Convention on Climate Change. Landfill gas is a potentially harmful emission that can be converted into a reliable environmentally-sustainable energy source used to generate electricity, fuel industries and heat buildings. The recovery and utilization of landfill gas is a win-win situation which makes good sense from local, regional and global perspectives. It provides the benefits of (1) reducing the release of greenhouse gases that contribute to global warming; (2) limiting odors; (3) controlling damage to vegetation; (4) reducing risks from explosions, fires and asphyxiation; (5) converting a harmful emission into a reliable energy source; and (6) creating a potential source of revenue and profit. Canadian landfills generate about 1 million tons of methane every year; the equivalent energy of 9 million barrels of oil (eight oil super tankers), or enough energy to meet the annual heating needs of more than half a million Canadian homes. Currently, twenty-seven facilities recover and combust roughly 25% of the methane generated by Canadian landfills producing about 3.2 PJ (10 15 Joules) of energy including 80 MW of electricity and direct fuel for nearby facilities (e.g., cement plants, gypsum board manufacturers, recycling facilities, greenhouses). This paper reviews landfill gas characteristics; environmental, health and safety impacts; landfill gas management in Canada; the costs of landfill gas recovery and utilization systems; and on-going projects on landfill gas utilization and flaring

  19. An efficient venturi scrubber system to remove submicron particles in exhaust gas.

    Science.gov (United States)

    Tsai, Chuen-Jinn; Lin, Chia-Hung; Wang, Yu-Min; Hunag, Cheng-Hsiung; Li, Shou-Nan; Wu, Zong-Xue; Wang, Feng-Cai

    2005-03-01

    An efficient venturi scrubber system making use of heterogeneous nucleation and condensational growth of particles was designed and tested to remove fine particles from the exhaust of a local scrubber where residual SiH4 gas was abated and lots of fine SiO2 particles were generated. In front of the venturi scrubber, normal-temperature fine-water mist mixes with high-temperature exhaust gas to cool it to the saturation temperature, allowing submicron particles to grow into micron sizes. The grown particles are then scrubbed efficiently in the venturi scrubber. Test results show that the present venturi scrubber system is effective for removing submicron particles. For SiO2 particles greater than 0.1microm, the removal efficiency is greater than 80-90%, depending on particle concentration. The corresponding pressure drop is relatively low. For example, the pressure drop of the venturi scrubber is approximately 15.4 +/- 2.4 cm H2O when the liquid-to-gas ratio is 1.50 L/m3. A theoretical calculation has been conducted to simulate particle growth process and the removal efficiency of the venturi scrubber. The theoretical results agree with the experimental data reasonably well when SiO2 particle diameter is greater than 0.1 microm.

  20. Cowdung gas

    Energy Technology Data Exchange (ETDEWEB)

    A basic guide for the design and construction of a small biogas plant is presented. The gas holder consists of a battery of seven used oil drums bound together with interconnected via plastic piping. Most other components, with the exception of metal valves and joints, are made of wood, stone or cement.

  1. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  2. Manure gas

    Energy Technology Data Exchange (ETDEWEB)

    Carre, I

    1948-11-01

    Descriptions are given of several batch digesters: the Algerian, Salubra, Betur, Baudot-Hardoll and Ofla, and Somagaz designs. Sketches of two Ducellier and Isman designs are given with a photograph of an installation consisting of four contiguous, rectangular concrete tanks. There are short explanations of the fundamentals and economics of the process, and of the use of the gas.

  3. Polarized spectroscopic properties of Er3+:Gd2SiO5 crystal and evaluation of Er3+:Yb3+:Gd2SiO5 crystal as a 1.55 μm laser medium

    International Nuclear Information System (INIS)

    Wang, H.; Huang, J.H.; Gong, X.H.; Chen, Y.J.; Lin, Y.F.; Luo, Z.D.; Huang, Y.D.

    2016-01-01

    An Er 3+ -doped Gd 2 SiO 5 single crystal with high optical quality has been grown by the Czochralski method. Polarized absorption and fluorescence spectra and fluorescence lifetime of the crystal were measured at room temperature. Intensity parameters, spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes were estimated on the basis of the Judd–Ofelt theory. Besides, potentiality of 1.55 μm laser emission in an Er 3+ –Yb 3+ co-doped Gd 2 SiO 5 crystal was evaluated.

  4. Trapping time of excitons in Si nanocrystals embedded in a SiO2 matrix

    Science.gov (United States)

    de Jong, E. M. L. D.; de Boer, W. D. A. M.; Yassievich, I. N.; Gregorkiewicz, T.

    2017-05-01

    Silicon (Si) nanocrystals (NCs) are of great interest for many applications, ranging from photovoltaics to optoelectonics. The photoluminescence quantum yield of Si NCs dispersed in SiO2 is limited, suggesting the existence of very efficient processes of nonradiative recombination, among which the formation of a self-trapped exciton state on the surface of the NC. In order to improve the external quantum efficiency of these systems, the carrier relaxation and recombination need to be understood more thoroughly. For that purpose, we perform transient-induced absorption spectroscopy on Si NCs embedded in a SiO2 matrix over a broad probe range for NCs of average sizes from 2.5 to 5.5 nm. The self-trapping of free excitons on surface-related states is experimentally and theoretically discussed and found to be dependent on the NC size. These results offer more insight into the self-trapped exciton state and are important to increase the optical performance of Si NCs.

  5. Study of SiO2-Si and metal-oxide-semiconductor structures using positrons

    Science.gov (United States)

    Leung, T. C.; Asoka-Kumar, P.; Nielsen, B.; Lynn, K. G.

    1993-01-01

    Studies of SiO2-Si and metal-oxide-semiconductor (MOS) structures using positrons are summarized and a concise picture of the present understanding of positrons in these systems is provided. Positron annihilation line-shape S data are presented as a function of the positron incident energy, gate voltage, and annealing, and are described with a diffusion-annihilation equation for positrons. The data are compared with electrical measurements. Distinct annihilation characteristics were observed at the SiO2-Si interface and have been studied as a function of bias voltage and annealing conditions. The shift of the centroid (peak) of γ-ray energy distributions in the depletion region of the MOS structures was studied as a function of positron energy and gate voltage, and the shifts are explained by the corresponding variations in the strength of the electric field and thickness of the depletion layer. The potential role of the positron annihilation technique as a noncontact, nondestructive, and depth-sensitive characterization tool for the technologically important, deeply buried interface is shown.

  6. Study of SiO2-Si and metal-oxide-semiconductor structures using positrons

    International Nuclear Information System (INIS)

    Leung, T.C.; Asoka-Kumar, P.; Nielsen, B.; Lynn, K.G.

    1993-01-01

    Studies of SiO 2 -Si and metal-oxide-semiconductor (MOS) structures using positrons are summarized and a concise picture of the present understanding of positrons in these systems is provided. Positron annihilation line-shape S data are presented as a function of the positron incident energy, gate voltage, and annealing, and are described with a diffusion-annihilation equation for positrons. The data are compared with electrical measurements. Distinct annihilation characteristics were observed at the SiO 2 -Si interface and have been studied as a function of bias voltage and annealing conditions. The shift of the centroid (peak) of γ-ray energy distributions in the depletion region of the MOS structures was studied as a function of positron energy and gate voltage, and the shifts are explained by the corresponding variations in the strength of the electric field and thickness of the depletion layer. The potential role of the positron annihilation technique as a noncontact, nondestructive, and depth-sensitive characterization tool for the technologically important, deeply buried interface is shown

  7. Self assembly of SiO2-encapsulated carbon microsphere composites

    International Nuclear Information System (INIS)

    Yang Yongzhen; Song Jingjing; Han Yanxing; Guo Xingmei; Liu Xuguang; Xu Bingshe

    2011-01-01

    SiO 2 was firstly coated onto the surface of carbon microspheres (CMSs) using tetraethyl orthosilicate (TEOS) as precursor by Stoeber method. Then SiO 2 -encapsulated CMS (CMS-SiO 2 ) composites were self-assembled by vertical deposition, in which the effects of deposition temperature and suspension concentration on the quality of self-assembling film were investigated. Morphologies and structures of the samples were characterized by field emission scanning electron microscopy, Fourier transformation infrared spectrometry, X-ray diffraction and thermogravimetry. The results show that uniform CMS-SiO 2 composites with good mono-dispersion were prepared by Stober method with 0.5 g of CMSs, 2 mL of TEOS, 30 mL of ammonia and 12 h of reaction time, the CMSs-based films with ordered and denser structure were prepared by vertical deposition using CMS-SiO 2 composites as monodipersion spheres under suspension concentration of 1 wt% and deposition temperature of 50 deg. C. The ultraviolet-visible absorption measurement shows that the absorbance of CMS-SiO 2 composite films grew steadily with increasing suspension concentration.

  8. Arthur Ramos e Anísio Teixeira na década de 1930

    Directory of Open Access Journals (Sweden)

    Fabíola Sircilli

    2005-08-01

    Full Text Available O artigo busca mostrar o movimento Escola Nova e autores ligados a ele. Foca-se a atuação de Arthur Ramos, médico que trabalhou ao lado de Anísio Teixeira, eminente pensador escolanovista, quando este foi diretor da instrução pública no Distrito Federal, nos anos 30. Ramos, que tinha fortes ligações com a Psicanálise, dirigiu o Instituto de Higiene Mental, órgão da administração municipal na gestão de Teixeira, onde foi instalada uma Seção de Ortofrenia e Higiene Mental. Ramos atuou empregando Freud, Jung e Adler tendo que adequar as teorias psicológicas que dispunha em meios aplicáveis à educação brasileira. Dados indicam que a inserção da psicanálise na educação foi favorecida pelas idéias deweyanas de Anísio Teixeira. Esse estudo é oriundo de pesquisa bibliográfica focada nas obras de Arthur Ramos: "Educação e Psicanálise" e "A criança problema".

  9. Photon Irradiation Response on Ge and Al-Doped SiO2 Optical Fibres

    Science.gov (United States)

    Yaakob, Nor Haliza; Wagiran, Husin; Ramli, Ahmad Termizi; Ali, Hassan; Asni, Hazila

    2010-07-01

    Recently, research groups have reported a number of radiation effects on the applications of SiO2 optical fibres with possible use as dosimeter material because these optical fibre provide a good basis for medical radiation dosimetry. The objective of this study is to investigate the thermoluminescence response and fading characteristic for germanium and aluminium doped SiO2 optical fibres with photon irradiation. These optical fibres are placed in solid phantom and irradiated to 6 and 10 MV photon beam at dose ranging from 0.06 Gy to 0.24 Gy using Primus MLC 3339 linear accelerator at Hospital Sultan Ismail, Johor Bahru. In fading studies, the TL measurements were continued up to 14 days period. The optical fibres will produce glow curves whereby the information is then analyzed. Al and Ge-doped optical fibres have a linear dose-TL signal relationship that is proportionality between the TL signal and the doses. Comparison for TL response between different linear accelerator showed a good agreement because these optical fibres also have a linear dose-TL signal relationship even using different equipments.

  10. Laser conditioning effect on HfO2/SiO2 film

    International Nuclear Information System (INIS)

    Wei Yaowei; Zhang Zhe; Liu Hao; Ouyang Sheng; Zheng Yi; Tang Gengyu; Chen Songlin; Ma Ping

    2013-01-01

    Laser conditioning is one of the important methods to improve the laser damage threshold of film optics. Firstly, a large aperture laser was used to irradiate the HfO 2 /SiO 2 reflectors, which were evaporated from hafnia and silica by e-beam. Secondly, a laser calorimeter was used to test the film absorption before and after laser irradiation. Focused ion beam (FIB) was few reported using on laser film, it was used to study the damage morphology and explore the cause of damage. The shooting of the partial ejection on nodule was obtained for the first time, which provided the basis for study the damage process. The results show that film absorption was decreased obviously after the laser irradiation, laser conditioning can raise the laser damage threshold by the 'cleaning mechanism'. For the HfO 2 /SiO 2 reflectors, laser conditioning was effective to eject the nodules on substrate. It resulted from the nodule residue not to affect the subsequent laser. In addition, laser conditioning was not effective to the nodule in the film, which might be from the material spatter in coating process. In this case, other method could be used to get rid of the nodules. (authors)

  11. Translocation of SiO2-NPs across in vitro human bronchial epithelial monolayer

    International Nuclear Information System (INIS)

    George, I; Vranic, S; Boland, S; Borot, M C; Marano, F; Baeza-Squiban, A

    2013-01-01

    Safe development and application of nanotechnologies in many fields require better knowledge about their potential adverse effects on human health. Evidence of abilities of nanoparticles (NPs) to cross epithelial barriers and reach secondary organs via the bloodstream led us to investigate the translocation of SiO 2 NPs of 50 nm (50 nm-SiO 2 -NPs) across human bronchial epithelial cells that are primary targets after exposure to inhaled NPs. We quantified the translocation of fluorescently labelled SiO 2 NPs at non-cytotoxic concentrations (5 and 10 μg/cm 2 ) across Calu-3 epithelial monolayer. After 14 days in culture Calu-3 cells seeded onto 3 μm-polycarbonate Transwell membranes formed an efficient bronchial barrier assessed by measurement of the transepithelial electric resistance and quantification of the permeability of the monolayer. After 24 hours of exposure, we observed a significant translocation of NPs that was more important when the initial NP concentration decreased. Confocal microscopy observations revealed NP uptake by cells and an important NP retention inside the porous membrane. In conclusion, 50 nm-SiO 2 -NPs can cross the human bronchial epithelial barrier without affecting the integrity of the epithelial cell monolayer.

  12. Wrinkling instability in graphene supported on nanoparticle-patterned SiO2

    Science.gov (United States)

    Cullen, William; Yamamoto, Mahito; Pierre-Louis, Olivier; Einstein, Theodore; Fuhrer, Michael

    2012-02-01

    Atomically-thin graphene is arguably the thinnest possible mechanical membrane: graphene's effective thickness (the thickness of an isotropic continuum slab which would have the same elastic and bending stiffness) is significantly less than 1 å, indicating that graphene can distort out-of-plane to conform to sub-nanometer features. Here we study the elastic response of graphene supported on a SiO2 substrate covered with SiO2 nanoparticles. At a low density of nanoparticles, graphene is largely pinned to the substrate due to adhesive interaction. However, with increasing nanoparticle density, graphene's elasticity dominates adhesion and strain is relieved by the formation of wrinkles which connect peaks introduced by the supporting nanoparticles. At a critical density, the wrinkles percolate, resulting in a wrinkle network. We develop a simple elastic model allowing for adhesion which accurately predicts the critical spacing between nanoparticles for wrinkle formation. This work has been supported by the University of Maryland NSF-MRSEC under Grant No. DMR 05-20471 with supplemental funding from NRI, and NSF-DMR 08-04976.

  13. Study of SiO2/PMMA/CE tri-component interpenetrating polymer network composites

    International Nuclear Information System (INIS)

    Wang Junlong; Wang Chuang; Jiao Gengsheng; Wang Qiuya

    2010-01-01

    A technology of conjugated tri-component interpenetrating polymer networks was applied to synthesize a nano-SiO 2 /polymethylmethacrylate (PMMA)/cyanate (CE) composite through an asynchronous synthesis way. The microstructure of the composite was characterized using infrared spectroscopy (IR) and transmission electron microscopy (TEM). The mechanical properties were measured in German-made DL-1000B and XCL-40 universal material test machines, respectively. Results showed that both the impact strength and the flexural strength were in the optimum status when 3% SiO 2 /PMMA/CE was chosen as a sample with the PMMA/CE ratio of 20/80. Compared with the strengths of pure cyanate, those of the composite were raised by 137.28% and 31.29%, respectively. When 3% nano-SiO 2 was added, the impact strength was increased by 29.96% and the flexural strength by 20.05%, compared with the strengths of polymers without SiO 2 . Analysis and measurements by IR and TEM indicated that no chemical reactions took place among components in the composite. The interpenetration of the conjugated tri-component improved the loading capacity of the polymer, hence the toughness enhancement of cyanate.

  14. Modification by SiO2 of Alumina Support for Light Alkane Dehydrogenation Catalysts

    Directory of Open Access Journals (Sweden)

    Giyjaz E. Bekmukhamedov

    2016-10-01

    Full Text Available Due to the continuously rising demand for C3–C5 olefins it is important to improve the performance of catalysts for dehydrogenation of light alkanes. In this work the effect of modification by SiO2 on the properties of the alumina support and the chromia-alumina catalyst was studied. SiO2 was introduced by impregnation of the support with a silica sol. To characterize the supports and the catalysts the following techniques were used: low-temperature nitrogen adsorption; IR-spectroscopy; magic angle spinning 29Si nuclear magnetic resonance; temperature programmed desorption and reduction; UV-Vis-, Raman- and electron paramagnetic resonance (EPR-spectroscopy. It was shown that the modifier in amounts of 2.5–7.5 wt % distributed on the support surface in the form of SiOx-islands diminishes the interaction between the alumina support and the chromate ions (precursor of the active component. As a result, polychromates are the compounds predominantly stabilized on the surface of the modified support; under thermal activation of the catalyst and are reduced to the amorphous Cr2O3. This in turn leads to an increase in the activity of the catalyst in the dehydrogenation of isobutane.

  15. Failure initiation and propagation of Li4SiO4 pebbles in fusion blankets

    International Nuclear Information System (INIS)

    Zhao Shuo; Gan Yixiang; Kamlah, Marc

    2013-01-01

    Lithium orthosilicate (Li 4 SiO 4 ) pebbles are considered to be a candidate as solid tritium breeder in the helium cooled pebble bed (HCPB) blanket. These ceramic pebbles might be crushed during thermomechanical loading in the blanket. In this work, the failure initiation and propagation of pebbles in pebble beds is investigated using the discrete element method (DEM). Pebbles are simplified as mono-sized elastic spheres. Every pebble has a contact strength in terms of critical strain energy, which is derived from a validated strength model and crush test data for pebbles from a specific batch of Li 4 SiO 4 pebbles. Pebble beds are compressed uniaxially and triaxially in DEM simulations. When the strain energy absorbed by a pebble exceeds its critical energy it fails. The failure initiation is defined as a given small fraction of pebbles crushed. It is found that the load level for failure initiation can be very low. For example, if failure initiation is defined as soon as 0.02% of the pebbles have been crushed, the pressure required for uniaxial loading is about 2.5 MPa. Therefore, it is essential to study the influence of failure propagation on the macroscopic response of pebble beds. Thus a reduction ratio defined as the size ratio of a pebble before and after its failure is introduced. The macroscopic stress–strain relation is investigated with different reduction ratios. A typical stress plateau is found for a small reduction ratio.

  16. Structure and magnetic properties of granular NiZn-ferrite - SiO2

    Directory of Open Access Journals (Sweden)

    Albuquerque Adriana Silva de

    1999-01-01

    Full Text Available Granular systems composed by nanostructured magnetic materials embedded in a non-magnetic matrix present unique physical properties that depend crucially on their nanostructure. In this work, we have studied the structural and magnetic properties of NiZn-ferrite nanoparticles embedded in SiO2, a granular system synthesized by sol-gel processing. Samples with ferrite volumetric fraction x ranging from 6% to 78% were prepared, and characterized by X-ray diffraction, Mössbauer spectroscopy and vibrating sample magnetometry. Our results show the formation of pure stoichiometric NiZn-ferrite in the SiO2 matrix for x < 34%. Above these fraction, our samples presented also small amounts of Fe2O3. Mössbauer spectroscopy revealed the superparamagnetic behaviour of the ferrimagnetic NiZn-ferrite nanoparticles. The combination of different ferrite concentration and heat treatments allowed the obtaintion of samples with saturation magnetization between 1.3 and 68 emu/g and coercivity ranging from 0 to 123 Oe, value which is two orders of magnitude higher than the coercivity of bulk NiZn-ferrite.

  17. Amorphous Ge quantum dots embedded in SiO2 formed by low energy ion implantation

    International Nuclear Information System (INIS)

    Zhao, J. P.; Huang, D. X.; Jacobson, A. J.; Chen, Z. Y.; Makarenkov, B.; Chu, W. K.; Bahrim, B.; Rabalais, J. W.

    2008-01-01

    Under ultrahigh vacuum conditions, extremely small Ge nanodots embedded in SiO 2 , i.e., Ge-SiO 2 quantum dot composites, have been formed by ion implantation of 74 Ge + isotope into (0001) Z-cut quartz at a low kinetic energy of 9 keV using varying implantation temperatures. Transmission electron microscopy (TEM) images and micro-Raman scattering show that amorphous Ge nanodots are formed at all temperatures. The formation of amorphous Ge nanodots is different from reported crystalline Ge nanodot formation by high energy ion implantation followed by a necessary high temperature annealing process. At room temperature, a confined spatial distribution of the amorphous Ge nanodots can be obtained. Ge inward diffusion was found to be significantly enhanced by a synergetic effect of high implantation temperature and preferential sputtering of surface oxygen, which induced a much wider and deeper Ge nanodot distribution at elevated implantation temperature. The bimodal size distribution that is often observed in high energy implantation was not observed in the present study. Cross-sectional TEM observation and the depth profile of Ge atoms in SiO 2 obtained from x-ray photoelectron spectra revealed a critical Ge concentration for observable amorphous nanodot formation. The mechanism of formation of amorphous Ge nanodots and the change in spatial distribution with implantation temperature are discussed

  18. HfO2 and SiO2 as barriers in magnetic tunneling junctions

    Science.gov (United States)

    Shukla, Gokaran; Archer, Thomas; Sanvito, Stefano

    2017-05-01

    SiO2 and HfO2 are both high-k, wide-gap semiconductors, currently used in the microelectronic industry as gate barriers. Here we investigate whether the same materials can be employed to make magnetic tunnel junctions, which in principle can be amenable for integration in conventional Si technology. By using a combination of density functional theory and the nonequilibrium Green's functions method for quantum transport we have studied the transport properties of Co [0001 ] /SiO2[001 ] /Co [0001 ] and Fe [001 ] /HfO2[001 ] /Fe [001 ] junctions. In both cases we found a quite large magnetoresistance, which is explained through the analysis of the real band structure of the magnets and the complex one of the insulator. We find that there is no symmetry spin filtering for the Co-based junction since the high transmission Δ2' band crosses the Fermi level, EF, for both spin directions. However, the fact that Co is a strong ferromagnet makes the orbital contribution to the two Δ2' spin subbands different, yielding magnetoresistance. In contrast for the Fe-based junction symmetry filtering is active for an energy window spanning between the Fermi level and 1 eV below EF, with Δ1 symmetry contributing to the transmission.

  19. Anomalous defect processes in Si implanted amorphous SiO2, II

    International Nuclear Information System (INIS)

    Fujita, Tetsuo; Fukui, Minoru; Okada, Syunji; Shimizu-Iwayama, Tsutomu; Hioki, Tatsumi; Itoh, Noriaki

    1994-01-01

    Aanomalous features of the defects in Si implanted amorphous SiO 2 are reported. The numbers of E 1 prime centers and B 2 centers are found to increase monotonically with implanted Si dose, in contrast to the saturating feature of these numbers in Ar implanted samples. Moreover, when H ions are implanted in amorphous SiO 2 predamaged by Si implantation, both of the density and the number of E 1 prime centers increase and they reach a constant value at a small H dose. We point out that these anomalies can be explained in terms of the difference in the cross-section for defect annihilation in the specimens implanted with Si ions and other ions, in accordance with the homogeneous model proposed by Devine and Golanski. We consider that the main mechanism of defect annihilation is the recombination of an E 1 prime center and an interstitial O, which is stabilized by an implanted Si, reducing the cross-section in Si-implanted specimens. ((orig.))

  20. Crack-resistant Al2O3-SiO2 glasses.

    Science.gov (United States)

    Rosales-Sosa, Gustavo A; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

    2016-04-07

    Obtaining "hard" and "crack-resistant" glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3-(100-x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3-SiO2 glasses. In particular, the composition of 60Al2O3 • 40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses.