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Sample records for alloy-yundk 25ba

  1. La2/5Ba2/5Ca1/5

    Indian Academy of Sciences (India)

    Unknown

    2003) are well known for their antiferromagnetic beha- viour as well as for their giant magnetoresistance. Substi- tution of La by monovalent alkali or divalent alkaline earth metal ions induces ferromagnetic behaviour in these oxides. Such substitution of lower valent ions for La3+ ions results in mixed valence at the Mn site, ...

  2. Evaluation of the glow curves of a new glass matrix

    International Nuclear Information System (INIS)

    Oliveira, Nathália S.; Souza, Samara P.; Ferreira, Pâmela Z.; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P.; Carrera, Betzabel N.S.; Watanabe, Shigueo

    2017-01-01

    Thermoluminescence is a dosimetric technique with may be used to personal, clinical, environmental and high doses. In this work a new glass matrix, with nominal composition of 20Li 2 CO 3 .10Al 2 O 3 .25BaO.45B 2 O 3 (mol%), was studied by the thermoluminescence technique. The glow curves was be analyzed, after the irradiation of this glass matrix with high doses. The results showed that this new glass matrix has a temperature peak in 260°C, which is ideal for dosimetry applications. (author)

  3. Evaluation of the glow curves of a new glass matrix; Avaliação das curvas de emissão termoluminescente de uma nova matriz vítrea

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Nathália S.; Souza, Samara P.; Ferreira, Pâmela Z.; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P., E-mail: anapaula.perini@ufu.br [Universidade Federal de Uberlândia (INFIS/UFU), Uberlândia, MG (Brazil). Instituto de Física; Caldas, Linda V.E. [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Carrera, Betzabel N.S.; Watanabe, Shigueo [Universidade de São Paulo (IF/USP), São Paulo, SP (Brazil). Instituto de Física

    2017-07-01

    Thermoluminescence is a dosimetric technique with may be used to personal, clinical, environmental and high doses. In this work a new glass matrix, with nominal composition of 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.25BaO.45B{sub 2}O{sub 3} (mol%), was studied by the thermoluminescence technique. The glow curves was be analyzed, after the irradiation of this glass matrix with high doses. The results showed that this new glass matrix has a temperature peak in 260°C, which is ideal for dosimetry applications. (author)

  4. Evaluation of a Field-Portable DNA Microarray Platform and Nucleic Acid Amplification Strategies for the Detection of Arboviruses, Arthropods, and Bloodmeals

    Science.gov (United States)

    2013-01-01

    heparin was purchased from Innovative Research (Novi, MI). Goat and horse whole blood was provided by our Veterinary Medicine Division (USAMRIID, Fort...quinquefasciatus (10) BA House NA Human Culex Th9-0122 Ae. aegypti (1) BA House DENV-3 DNP Aedes Th9-0164 Cx. tritaeniorhynchus (24) LT Farm JEV NA...Culex Th9-0167 Ae. albopictus (1) LT Farm NA NA Aedes Th9-0175 Cx. tritaeniorhynchus (25) LT Farm JEV NA Culex Th9-0235 Cx. tritaeniorhynchus (25) BA

  5. Structural distortions in Sr3-xAxMO4F (A=Ca, Ba; M=Al, Ga, In) anti-Perovskites and corresponding changes in photoluminescence

    International Nuclear Information System (INIS)

    Sullivan, Eirin; Avdeev, Maxim; Vogt, Thomas

    2012-01-01

    The ordered oxyfluoride family Sr 3 − x A x MO 4 F (A=Ca, Ba and M=Al, Ga) has formed the basis of several new inorganic phosphors, and shows great potential for use in phosphor-conversion LED lamp devices. This study examines the correlation between subtle structural changes and photoluminescent behaviour in some of these materials. In order to ascertain whether cation charge compensation has any influence on structure and subsequent photoluminescent behaviour, a comparison was carried out between phases with the nominal compositions Sr 2.975 Ce 0.025 AlO 4 F and Sr 2.95 Ce 0.025 Na 0.025 AlO 4 F using structural characterisation based upon high-resolution neutron powder diffraction (NPD) data. Additionally, NPD data has been used to elucidate the role of different M cations in these materials, using Sr 2.25 Ba 0.6 Eu 0.1 M 0.95 In 0.05 O 4−α F 1−δ (M=Al, Ga) to determine the effect M cation size has on structure and photoluminescent properties. - Graphical abstract: The structure of Sr3-xAxMO4F (A=Ca, Ba and M=Al, Ga) and excitation and emission spectra for Sr 2.25 Ba 0.6 Eu 0.1 Ga 0.95 In 0.05 O 4−α F 1−δ . Highlights: ► Correlation between structural changes and photoluminescence in Sr 3−x A x MO 4 F (A=Ca, Ba, M=Al, Ga). ► Comparison of Sr 2.975 Ce 0.025 AlO 4 F and Sr 2.95 Ce 0.025 Na 0.025 AlO 4 F using high-resolution NPD. ► Study of the effect of cation charge-compensation on structure and photoluminescent behaviour. ► Examination of high-resolution NPD data for Sr 2.25 Ba 0.6 Eu 0.1 M 0.95 In 0.05 O 4−α F 1−δ (M=Al, Ga). ► Determination of the effect M cation size has on structure and photoluminescent properties.

  6. Microstructure-property relationships in a gas diffusion layer (GDL) for Polymer Electrolyte Fuel Cells, Part I: effect of compression and anisotropy of dry GDL

    International Nuclear Information System (INIS)

    Holzer, L.; Pecho, O.; Schumacher, J.; Marmet, Ph.; Stenzel, O.; Büchi, F.N.; Lamibrac, A.; Münch, B.

    2017-01-01

    Highlights: • Methods are developed to predict transport properties of dry GDL in PE Fuel Cells. • Diffusivity and Permeability are reliably predicted based on 3D characteristics. • Predictions based on 3D microstructure match well with numerical simulations. • Anisotropy is due to in- and through-plane variation of tortuosity and hydraulic rad. • The methods can be used to predict relative permeability and diffusivity in wet GDL. - Abstract: New quantitative relationships are established between effective properties (gas diffusivity, permeability and electrical conductivity) for a dry GDL (25 BA) from SGL Carbon with the corresponding microstructure characteristics from 3D analysis. These microstructure characteristics include phase volume fractions, geodesic tortuosity, constrictivity and hydraulic radius. The latter two parameters include information from two different size distribution curves for bulges (continuous PSD) and for bottlenecks (MIP-PSD). X-ray tomographic microscopy is performed for GDL at different compression levels and the micro-macro-relationships are then established for the in-plane and through-plane directions. The predicted properties based on these relationships are compared with numerical transport simulations, which give very similar results and which can be summarized as follows: Gas diffusivity is higher in the in-plane than in the through-plane direction. Its variation with compression is mainly related to changes of porosity and geodesic tortuosity. Permeability is dominated by variations in hydraulic radius. Through-plane permeability is slightly higher than in-plane. Anisotropy of electrical conductivity is controlled by tortuosity, which is higher for the through-plane direction. A table with new quantitative relationships is provided, which are considered to be more accurate and precise than older descriptions (e.g. Carman-Kozeny, Bruggeman), because they are based on detailed topological information from 3D analysis

  7. Indoor/Outdoor Air Quality Assessment at School near the Steel Plant in Taranto (Italy

    Directory of Open Access Journals (Sweden)

    A. Di Gilio

    2017-01-01

    Full Text Available This study aims to investigate the air quality in primary school placed in district of Taranto (south of Italy, an area of high environmental risk because of closeness between large industrial complex and urban settlement. The chemical characterization of PM2.5 was performed to identify origin of pollutants detected inside school and the comparison between indoor and outdoor levels of PAHs and metals allowed evaluating intrusion of outdoor pollutants or the existence of specific indoor sources. The results showed that the indoor and outdoor levels of PM2.5, BaP, Cd, Ni, As, and Pb never exceeded the target values issued by World Health Organization (WHO. Nevertheless, high metals and PAHs concentrations were detected especially when school were downwind to the steel plant. The I/O ratio showed the impact of outdoor pollutants, especially of industrial markers as Fe, Mn, Zn, and Pb, on indoor air quality. This result was confirmed by values of diagnostic ratio as B(aP/B(gP, IP/(IP + BgP, BaP/Chry, and BaP/(BaP + Chry, which showed range characteristics of coke and coal combustion. However, Ni and As showed I/O ratio of 2.5 and 1.4, respectively, suggesting the presence of indoor sources.

  8. Formation and early hydration characteristics of C2.75B1.25A3$ in binary system of C2.75B1.25A3$-C2S

    Directory of Open Access Journals (Sweden)

    Wang, Shoude

    2016-09-01

    Full Text Available C2.75B1.25A3$ (2.75CaO•1.25BaO• 3Al2O3• SO3 is one of the important minerals and it govern-directly the early-strength of belite-barium calcium sulphoaluminate cement. In this paper a binary system C2.75B1.25A3$-C2S is selected to investigate the formation of C2.75B1.25A3$. In the range of 1100 °C–1200 °C, the earlier formed C2S hinders the formation of C2.75B1.25A3$. On the contrary, when the temperature is in the range of 1200 °C–1350 °C, the initially formed C2S could provide a surface for the nucleation of C2.75B1.25A3$ and cut down the potential barrier (?Gk* for the heterogeneous nucleation of C2.75B1.25A3$, which contributes to its formation. Moreover, at 1350 °C, the large amount of previously formed C2S benefits the extent of formation of C2.75B1.25A3$. The possible reason was that it could prevent sulfur evaporation. In early hydration age, AFm and AFt originating from C2.75B1.25A3$ hydration are found within 2 h and 12 h under 95% RH at 1 °C, respectively, whereas C2S is unhydrated at this moment.En el cemento de sulfoaluminato de calcio y bario, el C2.75B1.25A3$ (2.75CaO•1.25BaO• 3Al2 O3• SO3 es una de las principales fases, y regula directamente la resistencia inicial del cemento. En este trabajo, se ha seleccionado el sistema binario C2.75B1.25A3$-C2S para investigar la formación de C2.75B1.25A3$. En el rango de 1100 °C-1200 °C, el C2S formado anteriormente impide la formación de C2.75B1.25A3$, mientras que cuando la temperatura está entre 1200 °C-1350 °C, el C2S proporcionaría una superficie de nucleación de C2.75B1.25A3$ reduciendo la barrera de potencial (?Gk* para la nucleación heterogénea de C2.75B1.25A3$, lo que contribuye a su formación. Además, a 1350 °C, la gran cantidad de C2S formado beneficia la formación de C2.75B1.25A3$, ya que podía prevenir la evaporación del azufre. En las primeras etapas de la hidratación (entre 2 y 12h y 95% HR a 1 ºC se pueden encontrar AFM y AFt

  9. Methylomic profiling of cortex samples from completed suicide cases implicates a role for PSORS1C3 in major depression and suicide.

    Science.gov (United States)

    Murphy, T M; Crawford, B; Dempster, E L; Hannon, E; Burrage, J; Turecki, G; Kaminsky, Z; Mill, J

    2017-01-03

    Major depressive disorder (MDD) represents a major social and economic health issue and constitutes a major risk factor for suicide. The molecular pathology of suicidal depression remains poorly understood, although it has been hypothesised that regulatory genomic processes are involved in the pathology of both MDD and suicidality. In this study, genome-wide patterns of DNA methylation were assessed in depressed suicide completers (n=20) and compared with non-psychiatric, sudden-death controls (n=20) using tissue from two cortical brain regions (Brodmann Area 11 (BA11) and Brodmann Area 25 (BA25)). Analyses focused on identifying differentially methylated regions (DMRs) associated with suicidal depression and epigenetic variation were explored in the context of polygenic risk scores for major depression and suicide. Weighted gene co-methylation network analysis was used to identify modules of co-methylated loci associated with depressed suicide completers and polygenic burden for MDD and suicide attempt. We identified a DMR upstream of the PSORS1C3 gene, subsequently validated using bisulfite pyrosequencing and replicated in a second set of suicide samples, which is characterised by significant hypomethylation in both cortical brain regions in MDD suicide cases. We also identified discrete modules of co-methylated loci associated with polygenic risk burden for suicide attempt, but not major depression. Suicide-associated co-methylation modules were enriched among gene networks implicating biological processes relevant to depression and suicidality, including nervous system development and mitochondria function. Our data suggest that there are coordinated changes in DNA methylation associated with suicide that may offer novel insights into the molecular pathology associated with depressed suicide completers.

  10. Magnetoelectric and electric measurements of the (1-x)BiFeO{sub 3}–(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bochenek, D., E-mail: dariusz.bochenek@us.edu.pl [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Niemiec, P. [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Guzdek, P. [Institute of Electron Technology Cracow Division, 39, Zabłocie St., Cracow, 30-701 (Poland); Wzorek, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668, Warsaw (Poland)

    2017-07-01

    In the paper ferro–electro–magnetic (1-x)BiFeO{sub 3}-(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} (BF-PFN) solid solutions were obtained (containing the percentage BF/PFN: 60/40 and 70/30). Individual components of the solid solution were prepared by follows methods: synthesizing a powder BF was performed by calcining the simple oxides (Bi{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}), and synthesizing a powder PFN was carried out by calcining a mixture of complex oxides (FeNbO{sub 4}, PbO). Compaction of synthesized and mixed BiFeO{sub 3}, PbFe{sub 1/2}Nb{sub 1/2}O{sub 3} powders was carried out by free sintering methods. X–ray, microstructure, dielectric, magnetic and magnetoelectric studies, DC electrical conductivity and electrical hysteresis loop were carried out. Magnetoelectric effect measurements performed at room temperature showed coupling between electric and magnetic subsystem of the BF–PFN solid solutions. - Highlights: • BF-PFN samples have a densely packed microstructure, with well crystallized grains. • Bi atoms possibly migrate from BF toward PFN component during sintering. • BF-PFN have a diffuse character of the ferroelectric–paraelectric phase transition. • Magnetoelectric coefficient (α{sub ME}) for BF-PFN is higher, than for pure BF. • The α{sub ME} for BF-PFN is about three times higher than for 0.75BiFeO{sub 3}–0.25BaTiO{sub 3}.

  11. Effect of Ba in the glass characteristics of cesium loaded iron phosphate glasses

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Asuvathraman, R.; Vasudeva Rao, P.R.

    2015-01-01

    Radioactive 137 Cs extracted from high level nuclear waste, when immobilized in a suitable matrix can be used as a γsource in medical industry. Iron phosphate glass (IPG) is one of a suitable matrix for the immobilization of 137 Cs prior to the immobilization of 137 Cs in IPG, it is essential to optimize the immobilization conditions using natural (inactive) cesium. Glass characteristics of inactive Cs loaded iron phosphate glasses were already explored in our earlier studies. However, the change in glass characteristics of 137 Cs loaded iron phosphate glass to 137 Ba loaded iron phosphate glass need to be studied before the immobilization of 137 Cs in iron phosphate glass as 137 Cs transforms to 137 Ba due to nuclear transmutation ( 137 Cs(β,γ) 137 Ba). This paper reports the studies on such a behaviour by incorporating inactive Ba in cesium loaded iron phosphate glasses. Cs and Ba loaded iron phosphate glasses were prepared by melt quench technique in air using appropriate amounts of Fe 2 O 3 , NH 4 H 2 PO 4 , Ba(OH) 2.8 H 2 O and Cs 2 CO 3 . The chemicals were added such that the glass formed possesses the batch composition of (a) 21.4 wt. % Fe 2 O 3 -45 wt. % Cs 2 O-5 wt % BaO-P 2 O 5 (henceforth referred as IP50Cs45Ba5); (b) 21.4 wt. % Fe 2 O 3 -25 wt. % Cs 2 O-25 wt % BaO-P 2 O5 (henceforth referred as IP50Cs25Ba25). The thermal expansion measurements were also carried out using a home-built quartz push-rod dilatometer. The data related to change in thermal expansion behaviour, glass forming ability, glass stability and structural changes in phosphate network due to the partial replacement of Cs with Ba will also be discussed. (author)

  12. Structural, dielectric and magnetic properties of Mn modified xBiFeO{sub 3}-(1−x)BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Zhonghua, E-mail: zhdai@mail.xjtu.edu.cn [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Liu, Lu; Ying, Guobing; Yuan, Ming [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ren, Xiaobing [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2017-07-15

    Manganese doped xBiFeO{sub 3}-(1−x)BaTiO{sub 3}(x=0.67–0.82) ceramics were prepared by solid-state method. The structural, dielectric and magnetic properties were investigated after annealing in vacuum at 773 K. X-ray diffraction analysis indicated that all samples crystallized in pure perovskite structure. The ceramics displays a typical ferroelectric loop, with a max remnant polarization P{sub r} of 25.6 µC/cm{sup 2}. The piezoelectric coefficient d{sub 33} of Manganese doped 0.67BiFeO{sub 3}0.33BaTiO{sub 3} is 139 pC/N and its temperature dependence of dielectric constant exhibits a broad anomaly. The Manganese doped 0.75BiFeO{sub 3}0.25BaTiO{sub 3} ceramic shows ferrimagnetism at room temperature, with remnant magnetization M{sub r} of 0.31 emu/g and ferrimagnetic transition temperature T{sub N} of ~420 °C. - Highlights: • In this manuscript, a technique combined Mn doping which is able to fabricate point defects and annealing in vacuum which can stabilize the unstable ion was investigated. We studied the electrical properties of Mn doped BiFeO{sub 3}-BaTiO{sub 3} ceramics after vacuum annealing treatment at appropriate temperature. • Our result is that Mn modification and heat treatment are effective methods to solve the problem of high leakage of BiFeO{sub 3}-BaTiO{sub 3} system ceramic prepared by solid-state method. It exhibited a enhanced field-induced ferromagnetic ordering with promising potential in spintronics and recording media applications.

  13. Methylomic profiling of cortex samples from completed suicide cases implicates a role for PSORS1C3 in major depression and suicide

    Science.gov (United States)

    Murphy, T M; Crawford, B; Dempster, E L; Hannon, E; Burrage, J; Turecki, G; Kaminsky, Z; Mill, J

    2017-01-01

    Major depressive disorder (MDD) represents a major social and economic health issue and constitutes a major risk factor for suicide. The molecular pathology of suicidal depression remains poorly understood, although it has been hypothesised that regulatory genomic processes are involved in the pathology of both MDD and suicidality. In this study, genome-wide patterns of DNA methylation were assessed in depressed suicide completers (n=20) and compared with non-psychiatric, sudden-death controls (n=20) using tissue from two cortical brain regions (Brodmann Area 11 (BA11) and Brodmann Area 25 (BA25)). Analyses focused on identifying differentially methylated regions (DMRs) associated with suicidal depression and epigenetic variation were explored in the context of polygenic risk scores for major depression and suicide. Weighted gene co-methylation network analysis was used to identify modules of co-methylated loci associated with depressed suicide completers and polygenic burden for MDD and suicide attempt. We identified a DMR upstream of the PSORS1C3 gene, subsequently validated using bisulfite pyrosequencing and replicated in a second set of suicide samples, which is characterised by significant hypomethylation in both cortical brain regions in MDD suicide cases. We also identified discrete modules of co-methylated loci associated with polygenic risk burden for suicide attempt, but not major depression. Suicide-associated co-methylation modules were enriched among gene networks implicating biological processes relevant to depression and suicidality, including nervous system development and mitochondria function. Our data suggest that there are coordinated changes in DNA methylation associated with suicide that may offer novel insights into the molecular pathology associated with depressed suicide completers. PMID:28045465

  14. Pure and Y-substituted BaZrO3 ceramics. A possible support material for fabrication of YBa2Cu3O7-x high-Tc superconductors

    International Nuclear Information System (INIS)

    Wang Xiandong.

    1993-01-01

    This thesis concerns the preparation and characterization of cuprate based high-T c superconductors (Y-123 and Bi-2223) and especially development and testing of BaZrO 3 based materials. The formation of YBa 2 Cu 3 O y (Y-123) by a CO 2 -free route involving reaction sintering of stoichiometric mixtures of chemically prepared fine powders of Y 2 BaCuO 5 , BaCuO 2 and CuO have been studied by thermal and XRD analysis. The synthesis and sintering of BaZrO 3 powders prepared by the hydroxide-alkoxide-methanol sol-gel route have been studied. The phase relations in the system BaO-Y 2 O 3 -ZrO 2 have been studied to determine the solid solubility limits for the perovskite phase Ba X Y Y Zr Z O N (X+X+Z=3) at 1500 deg. C. In the binary system Y 2 O 3 -BaZrO 3 the solubility limit was found to be ≅19 mol% Y 2 O 3 , i.e. Ba 0.81 Y 0. 4 2 Zr 0.81 O 3 . along the joint BaYO 2.5 -Ba the boundary was determined to be at BaY 0.21 Zr 0 . 79 O 2.895 . evidence for a new solid solution series between Ba 3 Y 4 O 9 and ZrO 2 are given, and a partial 1500 deg. C phase diagram for the ternary system BaO-Y 2 O 3 -ZrO 2 is presented. The growth of BaZrO 3 single crystals have been attempted both by a laser zone floating technique and flux methods. The compatibility between YBa 2 Cu 3 O 7 -X and BaZrO 3 , Ba X Y Y Zr Z O 3-δ as well as BaHfO 3 have been studied at 950 deg. and 1050 deg. C. The results show the four most promising candidates as support materials for fabrication of YBa 2 Cu 3 O y to be BaHfO 3 , BaY 0.05 Zr 0.95 O 2.975 , , BaZrO 3 and BaY 0.1 Zr 0.9 O 2.95 . (EG)

  15. Structure-property relations in new fluorophosphate glasses singly- and co-doped with Er{sup 3+} and Yb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Tássia S.; Moreira Silva, Raphaell J.; Oliveira Junior, Marcos de; Ferrari, Cynthia R. [Physics Institute of São Carlos, University of São Paulo, São Carlos, SP 13566-590 (Brazil); Poirier, Gäel Y. [Science and Technology Institute, Federal University of Alfenas, Poços de Caldas, MG 37715-400 (Brazil); Eckert, Hellmut, E-mail: eckert@ifsc.usp.br [Physics Institute of São Carlos, University of São Paulo, São Carlos, SP 13566-590 (Brazil); Physical Chemistry Institute, Westfälische Wilhelms Universität Münster, Münster D-48149 (Germany); Camargo, Andrea S.S. de, E-mail: andreasc@ifsc.usp.br [Physics Institute of São Carlos, University of São Paulo, São Carlos, SP 13566-590 (Brazil)

    2015-05-01

    Rare earth (RE{sup 3+})-doped fluorophosphate glasses are among the most promising candidates for high-efficiency laser generation in the near-infrared spectral region. By proper choice of composition, these materials can combine the advantages of fluorides (low phonon energies, low refractive indices, extensive optical window, low hygroscopicity) and of oxides (high chemical and mechanical stability and high dopant solubility), resulting in enhancement of the RE{sup 3+} emissive properties. In this work, we present the synthesis and structural/spectroscopic investigation of new glasses with composition 25BaF{sub 2}25SrF{sub 2}(30-x)Al(PO{sub 3}){sub 3}xAlF{sub 3}(20-z)YF{sub 3}:zREF{sub 3}, where x = 20 or 15, RE = Er{sup 3+} and/or Yb{sup 3+}, z = 0.25–5.0 mol%. Results indicate considerable improvement of the emissive properties of both ions when compared to phosphate or even other fluorophosphate host compositions. Long excited state lifetimes (τ = 10 ms for the Er{sup 3+} level {sup 4}I{sub 13/2}, and τ = 1.3 ms for the Yb{sup 3+} level {sup 2}F{sub 5/2}) imply high fluorescence quantum efficiencies η (up to 85% for both ions). Structural characterization by Raman and multinuclear solid state NMR spectroscopies indicate that the metaphosphate-type chain structure of the Al(PO{sub 3}){sub 3} vitreous framework is partially depolymerized and dominated by Q{sup (0)} and Q{sup (1)} units crosslinked by six-coordinate Al species. As revealed by {sup 27}Al{"3"1P} rotational echo double resonance (REDOR) NMR results the average local aluminum environment of the x = 20 sample comprises 1.6 phosphate and 4.4 fluoride species. These results indicate a clear bonding preference between aluminum and phosphorus, which is consistent with the desired dominance of fluoride species in the local environment of the rare earth and alkaline earth atoms in these glasses. - Highlights: • New fluorophosphate glass composition with excellent photophysical properties.

  16. Structure-property relations in new fluorophosphate glasses singly- and co-doped with Er3+ and Yb3+

    International Nuclear Information System (INIS)

    Gonçalves, Tássia S.; Moreira Silva, Raphaell J.; Oliveira Junior, Marcos de; Ferrari, Cynthia R.; Poirier, Gäel Y.; Eckert, Hellmut; Camargo, Andrea S.S. de

    2015-01-01

    Rare earth (RE 3+ )-doped fluorophosphate glasses are among the most promising candidates for high-efficiency laser generation in the near-infrared spectral region. By proper choice of composition, these materials can combine the advantages of fluorides (low phonon energies, low refractive indices, extensive optical window, low hygroscopicity) and of oxides (high chemical and mechanical stability and high dopant solubility), resulting in enhancement of the RE 3+ emissive properties. In this work, we present the synthesis and structural/spectroscopic investigation of new glasses with composition 25BaF 2 25SrF 2 (30-x)Al(PO 3 ) 3 xAlF 3 (20-z)YF 3 :zREF 3 , where x = 20 or 15, RE = Er 3+ and/or Yb 3+ , z = 0.25–5.0 mol%. Results indicate considerable improvement of the emissive properties of both ions when compared to phosphate or even other fluorophosphate host compositions. Long excited state lifetimes (τ = 10 ms for the Er 3+ level 4 I 13/2 , and τ = 1.3 ms for the Yb 3+ level 2 F 5/2 ) imply high fluorescence quantum efficiencies η (up to 85% for both ions). Structural characterization by Raman and multinuclear solid state NMR spectroscopies indicate that the metaphosphate-type chain structure of the Al(PO 3 ) 3 vitreous framework is partially depolymerized and dominated by Q (0) and Q (1) units crosslinked by six-coordinate Al species. As revealed by 27 Al{ 31 P} rotational echo double resonance (REDOR) NMR results the average local aluminum environment of the x = 20 sample comprises 1.6 phosphate and 4.4 fluoride species. These results indicate a clear bonding preference between aluminum and phosphorus, which is consistent with the desired dominance of fluoride species in the local environment of the rare earth and alkaline earth atoms in these glasses. - Highlights: • New fluorophosphate glass composition with excellent photophysical properties. • Detailed structural insights by multinuclear solid state NMR. • Rare earth bonding preference to

  17. Reduced integrity of the uncinate fasciculus and cingulum in depression: A stem-by-stem analysis.

    Science.gov (United States)

    Bhatia, Kartik D; Henderson, Luke A; Hsu, Eugene; Yim, Mark

    2018-04-07

    The subgenual cingulate gyrus (Brodmann's Area 25: BA25) is hypermetabolic in depression and has been targeted successfully with deep brain stimulation. Two of the white matter tracts that play a role in treatment response are the uncinate fasciculus (UF) and the cingulum bundle. The UF has three prefrontal stems, the most medial of which extends from BA25 (which deals with mood regulation) and the most lateral of which extends from the dorso-lateral prefrontal cortex (concerned with executive function). The cingulum bundle has numerous fibers connecting the lobes of the cerebrum, with the longest fibers extending from BA25 to the amygdala. We hypothesize that there is reduced integrity in the UF, specific to the medial prefrontal stems, as well as in the subgenual and amygdaloid fibers of the cingulum bundle. Our secondary hypothesis is that these changes are present from the early stages of depression. Compare the white matter integrity of stems of the UF and components of the cingulum bundle in first-onset depressed, recurrent/chronic depressed, and non-depressed control subjects. Depressed patients (n = 103, first-onset = 57, chronic = 46) and non-depressed control subjects (n = 74) underwent MRI with 32-directional DTI sequences. The uncinate fasciculi and cingulum bundles were seeded, and the fractional anisotropy (FA) measured in each of the three prefrontal stems and the body of the UF, as well as the subgenual, body, and amygdaloid fiber components of the cingulum bundle. FA measurements were compared between groups using ANOVA testing with post-hoc Tukey analysis. There were significant reductions in FA in the subgenual and polar stems of the UF bilaterally, as well as the subgenual and amygdaloid fibers of the cingulum bundle, in depressed patients compared with controls (p lateral UF stem or the main body of the cingulum. No significant difference was demonstrated in any of the tracts between first-onset and chronic depression patients

  18. Luminescent properties of Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4}F oxyfluorides

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sangmoon, E-mail: spark@silla.ac.kr [Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of)

    2012-04-15

    Effective orange Sm{sup 3+}-doped Sr{sub 2.5}Ba{sub 0.5}AlO{sub 4}F phosphors excited at 254 and 408 nm excitation were prepared by the solid-state method. The excitation and emission spectra of Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4}F and Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4-{alpha}}F{sub 1-{delta}} (x=0.001{approx}0.1) based on photoluminescence spectroscopy are investigated. The defects in anion-deficient Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4-{alpha}}F{sub 1-{delta}} (x=0.001, 0.01) are monitored by broad-band photoluminescence emission centered near 480 nm along with the orange emission transitions of Sm{sup 3+}. CIE values and relative luminescent intensities of Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4}F and Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4-{alpha}}F{sub 1-{delta}} by changing the Sm{sup 3+} content (x=0.001{approx}0.1) are discussed. - Highlights: Black-Right-Pointing-Pointer Under the excitation of 408 nm competent orange emitting Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}AlO{sub 4}F phosphor is initiated. Black-Right-Pointing-Pointer Sm{sup 3+}-activated oxyfluoride phosphor is quite effective to prepare white-emitting light for near-UV LED applications. Black-Right-Pointing-Pointer Defects could be visibly created in the Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}Al O{sub 4}F host lattices when Sm{sup 3+} ions are doped less than 5 mol %. Black-Right-Pointing-Pointer The gradual substitution of Sm{sup 3+} contents in oxyfluoride hosts is amenable to change CIE values and desired emitting intensity.

  19. New Method of Preparation of Isomers of the (Ca0.1La0.9)(Ba1.6.5La0.35)Cu3Oy Superconductor with Predicted Maximal Tc

    International Nuclear Information System (INIS)

    Knizhnik, A.; Reisner, G.M.; Men, A.; Eckstein, Y.

    1998-01-01

    The 123 superconductor (Ca 0.1 La 0.9 )(Ba 1.6.5 La 0.35 )Cu 3 O y (c) has been prepared by the usual carbonate-oxide method. After oxygenation to the optimal oxygen doping of y=7.135, the maximal T c =57K. We prepared (c) also via reaction (1): 0.75La(La 0.25 Ba 1.75 )Cu 3 O 6.782 +0.25Ca 0.4 La 0.6 (La 0.65 Ba 1.35 )Cu 3 O 6.806 + 0.033O 2 (Ca 0. 1La 9 )(Ba 1.65 La 0.35 )Cu 3 ) 6.854 (1) The initial reagents are also superconductors. The first (a) has a maximal T c =57K, second (b) - 81K. In reference [1] we have shown that several isomers having the same general formula (c), may exist each having different ratios of the follow- ing possible unit cells: LaBa 2 Cu 3 O y , La(BaLa)Cu 3 O y , LaLa 2 Cu 3 O y , CaBa 2 Cu 3 O y , Ca(BaLa)Cu30 , CaLa2Cu30 . These isomers are formed at different temperatures of the preparation of (c) by carbonate-oxide method [1]. After the formation of compound (c) has been completed, further heating, even to higher temperatures, cannot change one isomer into another. Thus, there is no equilibrium between the (c) isomers and, if there also is no equilibrium in the cases of both isomers (a) and (b), then reaction (1) should not change the ratio of the unit cells. Each cell (i), which is present in (a) in concentration q i (a), should be present in (c) in concentration 0.75q i (a); analogously, each cell (i) which is present in (b) in concentration q i (b) should be present in (c) in concentration 0.25q i (b). According to the cluster component method, [2], T cmax = Σq i T i , where T i is T cmax of such a hypothetical sample, which contains cells (i) only. Thus the expected T cmax of (c), prepared via reaction (1), is: Σ0.75q i (a)T i + Σ0.25q i (b)T i = 0.75 x 57 + 0.25 x 81 = 63K, i.e. higher by 6 degrees than the T cmax of (c) prepared by the usual method. We studied reaction (1) via X-ray diffraction. XRD spectra showed that the intensity of the reagents peaks decrease with the time of the reaction and after 100 hours at 950 deg