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Sample records for excited thin bismuth

  1. Induced electronic anisotropy in bismuth thin films

    SciTech Connect

    Liao, Albert D.; Yao, Mengliang; Opeil, Cyril; Katmis, Ferhat; Moodera, Jagadeesh S.; Li, Mingda; Tang, Shuang; Dresselhaus, Mildred S.

    2014-08-11

    We use magneto-resistance measurements to investigate the effect of texturing in polycrystalline bismuth thin films. Electrical current in bismuth films with texturing such that all grains are oriented with the trigonal axis normal to the film plane is found to flow in an isotropic manner. By contrast, bismuth films with no texture such that not all grains have the same crystallographic orientation exhibit anisotropic current flow, giving rise to preferential current flow pathways in each grain depending on its orientation. Extraction of the mobility and the phase coherence length in both types of films indicates that carrier scattering is not responsible for the observed anisotropic conduction. Evidence from control experiments on antimony thin films suggests that the anisotropy is a result of bismuth's large electron effective mass anisotropy.

  2. Simultaneous solution-based generation and characterization of crystalline bismuth thin film by femtosecond laser spectroscopy

    SciTech Connect

    Zhu, Liangdong; Keszler, Douglas A.; Fang, Chong; Saha, Sumit; Liu, Weimin; Wang, Yanli

    2015-08-10

    We demonstrate generation and characterization of crystalline bismuth thin film from triphenyl bismuth in methanol. Upon ultraviolet (267 nm) femtosecond laser irradiation of the solution, a thin film of elemental bismuth forms on the inner side of the sample cuvette, confirmed by detection of the coherent A{sub 1g} optical phonon mode of crystalline bismuth at ∼90 cm{sup −1}. Probe pulses at 267 and 400 nm are used to elucidate the excited state potential energy surface and photochemical reaction coordinate of triphenyl bismuth in solution with femtosecond resolution. The observed phonon mode blueshifts with increasing irradiation time, likely due to the gradual thickening of nascent bismuth thin film to ∼80 nm in 90 min. From transient absorption with the 400 nm probe, we observe a dominant ∼4 ps decay time constant of the excited-state absorption signal, which is attributed to a characteristic metal-ligand bond-weakening/breaking intermediate enroute to crystalline metallic thin film from the solution precursor molecules. Our versatile optical setup thus opens an appealing avenue to characterize the laser-induced crystallization process in situ and prepare high-quality thin films and nanopatterns directly from solution phase.

  3. Bismuth pyrochlore thin films for dielectric energy storage

    SciTech Connect

    Michael, Elizabeth K. Trolier-McKinstry, Susan

    2015-08-07

    Thin films of cubic pyrochlore bismuth zinc niobate, bismuth zinc tantalate, and bismuth zinc niobate tantalate were fabricated using chemical solution deposition. This family of materials exhibited moderate relative permittivities between 55 ± 2 and 145 ± 5 for bismuth zinc tantalate and bismuth zinc niobate, respectively, and low loss tangents on the order of 0.0008 ± 0.0001. Increases in the concentration of the tantalum end member increased the dielectric breakdown strength. For example, at 10 kHz, the room temperature breakdown strength of bismuth zinc niobate was 5.1 MV/cm, while that of bismuth zinc tantalate was 6.1 MV/cm. This combination of a high breakdown strength and a moderate permittivity led to a high discharged energy storage density for all film compositions. For example, at a measurement frequency of 10 kHz, bismuth zinc niobate exhibited a maximum recoverable energy storage density of 60.8 ± 2.0 J/cm{sup 3}, while bismuth zinc tantalate exhibited a recoverable energy storage density of 60.7 ± 2.0 J/cm{sup 3}. Intermediate compositions of bismuth zinc niobate tantalate offered higher energy storage densities; at 10 mol. % tantalum, the maximum recoverable energy storage density was ∼66.9 ± 2.4 J/cm{sup 3}.

  4. Entropy driven atomic motion in laser-excited bismuth.

    PubMed

    Giret, Y; Gellé, A; Arnaud, B

    2011-04-15

    We introduce a thermodynamical model based on the two-temperature approach in order to fully understand the dynamics of the coherent A(1g) phonon in laser-excited bismuth. Using this model, we simulate the time evolution of (111) Bragg peak intensities measured by Fritz et al. [Science 315, 633 (2007)] in femtosecond x-ray diffraction experiments performed on a bismuth film for different laser fluences. The agreement between theoretical and experimental results is striking not only because we use fluences very close to the experimental ones but also because most of the model parameters are obtained from ab initio calculations performed for different electron temperatures.

  5. Bismuth(III) dialkyldithiophosphates: Facile single source precursors for the preparation of bismuth sulfide nanorods and bismuth phosphate thin films

    SciTech Connect

    Biswal, Jasmine B.; Garje, Shivram S.; Nuwad, Jitendra; Pillai, C.G.S.

    2013-08-15

    Two different phase pure materials (Bi{sub 2}S{sub 3} and Bi{sub 2}P{sub 4}O{sub 13}) have been prepared under different conditions using the same single source precursors. Solvothermal decomposition of the complexes, Bi(S{sub 2}P(OR){sub 2}){sub 3} [where, R=Methyl (Me) (1), Ethyl (Et) (2), n-Propyl (Pr{sup n}) (3) and iso-Propyl (Pr{sup i}) (4)] in ethylene glycol gave orthorhombic bismuth sulfide nanorods, whereas aerosol assisted chemical vapor deposition (AACVD) of the same precursors deposited monoclinic bismuth tetraphosphate (Bi{sub 2}P{sub 4}O{sub 13}) thin films on glass substrates. Surface study of the thin films using SEM illustrated the formation of variety of nanoscale morphologies (spherical-, wire-, pendent-, doughnut- and flower-like) at different temperatures. AFM studies were carried out to evaluate quality of the films in terms of uniformity and roughness. Thin films of average roughness as low as 1.4 nm were deposited using these precursors. Photoluminescence studies of Bi{sub 2}P{sub 4}O{sub 13} thin films were also carried out. - Graphical abstract: Solvothermal decomposition of bismuth(III) dialkyldithiophosphates in ethylene glycol gave Bi{sub 2}S{sub 3} nanoparticles, whereas aerosol assisted chemical vapor deposition of these single source precursors deposited Bi{sub 2}P{sub 4}O{sub 13} thin films. Display Omitted - Highlights: • Preparation of phase pure orthorhombic Bi{sub 2}S{sub 3} nanorods and monoclinic Bi{sub 2}P{sub 4}O{sub 13} thin films. • Use of single source precursors for deposition of bismuth phosphate thin films. • Use of solvothermal decomposition and AACVD methods. • Morphology controlled synthesis of Bi{sub 2}P{sub 4}O{sub 13} thin films. • Bi{sub 2}S{sub 3} nanorods and Bi{sub 2}P{sub 4}O{sub 13} thin films using same single source precursors.

  6. Electrical resistivity of thin bismuth films

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Katyal, O. P.

    1990-05-01

    The effect of the film thickness of a bismuth film deposited on glass substrate on its electrical resistivity was investigated for films from 41 to 225 nm thickness, in the temperature range 77-350 K. Results show that the electrical resistivity decreases with increasing temperature and that, for films 98.3 and 225.9 nm thick there exists a minimum (between 260 and 350 K) in resistivity at some temperature, Tc. This minimum shifts toward higher temperature for thinner samples, and lies above 350 K. The thickness dependence of the bismuth film resistivity, obtained at 77, 150, and 300 K, can be explained by a modified Fuchs model, which takes into account the thickness dependence of carrier density.

  7. Bismuth(III) dialkyldithiophosphates: Facile single source precursors for the preparation of bismuth sulfide nanorods and bismuth phosphate thin films

    NASA Astrophysics Data System (ADS)

    Biswal, Jasmine B.; Garje, Shivram S.; Nuwad, Jitendra; Pillai, C. G. S.

    2013-08-01

    Two different phase pure materials (Bi2S3 and Bi2P4O13) have been prepared under different conditions using the same single source precursors. Solvothermal decomposition of the complexes, Bi{S2P(OR)2}3 [where, R=Methyl (Me) (1), Ethyl (Et) (2), n-Propyl (Prn) (3) and iso-Propyl (Pri) (4)] in ethylene glycol gave orthorhombic bismuth sulfide nanorods, whereas aerosol assisted chemical vapor deposition (AACVD) of the same precursors deposited monoclinic bismuth tetraphosphate (Bi2P4O13) thin films on glass substrates. Surface study of the thin films using SEM illustrated the formation of variety of nanoscale morphologies (spherical-, wire-, pendent-, doughnut- and flower-like) at different temperatures. AFM studies were carried out to evaluate quality of the films in terms of uniformity and roughness. Thin films of average roughness as low as 1.4 nm were deposited using these precursors. Photoluminescence studies of Bi2P4O13 thin films were also carried out.

  8. Low-temperature Hall effect in bismuth chalcogenides thin films

    NASA Astrophysics Data System (ADS)

    Kuntsevich, A. Yu.; Gabdullin, A. A.; Prudkogliad, V. A.; Selivanov, Yu. G.; Chizhevskii, E. G.; Pudalov, V. M.

    2016-12-01

    Bismuth chalcogenides are the most studied 3D topological insulators. As a rule, at low temperatures, thin films of these materials demonstrate positive magnetoresistance due to weak antilocalization. Weak antilocalization should lead to resistivity decrease at low temperatures; in experiments, however, resistivity grows as temperature decreases. From transport measurements for several thin films (with various carrier density, thickness, and carrier mobility), and by using a purely phenomenological approach, with no microscopic theory, we show that the low-temperature growth of the resistivity is accompanied by growth of the Hall coefficient, in agreement with the diffusive electron-electron interaction correction mechanism. Our data reasonably explain the low-temperature resistivity upturn.

  9. Large-Area Dry Transfer of Single-Crystalline Epitaxial Bismuth Thin Films.

    PubMed

    Walker, Emily S; Na, Seung Ryul; Jung, Daehwan; March, Stephen D; Kim, Joon-Seok; Trivedi, Tanuj; Li, Wei; Tao, Li; Lee, Minjoo L; Liechti, Kenneth M; Akinwande, Deji; Bank, Seth R

    2016-11-09

    We report the first direct dry transfer of a single-crystalline thin film grown by molecular beam epitaxy. A double cantilever beam fracture technique was used to transfer epitaxial bismuth thin films grown on silicon (111) to silicon strips coated with epoxy. The transferred bismuth films retained electrical, optical, and structural properties comparable to the as-grown epitaxial films. Additionally, we isolated the bismuth thin films on freestanding flexible cured-epoxy post-transfer. The adhesion energy at the bismuth/silicon interface was measured to be ∼1 J/m(2), comparable to that of exfoliated and wet transferred graphene. This low adhesion energy and ease of transfer is unexpected for an epitaxially grown film and may enable the study of bismuth's unique electronic and spintronic properties on arbitrary substrates. Moreover, this method suggests a route to integrate other group-V epitaxial films (i.e., phosphorus) with arbitrary substrates, as well as potentially to isolate bismuthene, the atomic thin-film limit of bismuth.

  10. Robust surface state transport in thin bismuth nanoribbons

    PubMed Central

    Ning, Wei; Kong, Fengyu; Han, Yuyan; Du, Haifeng; Yang, Jiyong; Tian, Mingliang; Zhang, Yuheng

    2014-01-01

    While a two-dimensional (2D) metallic surface state in bismuth has been proposed, experimental 2D evidence of quantum transport, e.g., angular dependent Shubnikov-de Haas (SdH) oscillations is still lacking. Here, we report the angular-dependent magnetoresistance measurements in single-crystal Bi nanoribbons, and found that both the low-field weak antilocalization behavior and the high-field angle-dependent SdH oscillations follow exactly the 2D character, indicative of the 2D metallic surface states which dominate the transport properties of thin Bi nanoribbons. Moreover, by controllable exposing the ribbons to ambient environment (1 atm and room temperature), the metallic surface states were found to be robust to the oxidation although the carrier density in the surface states are modified after the exposures. These results suggest that the metallic surface states in Bi nanoribbons should be topologically protected which can provide key information in understanding the surface properties of Bi in nanometer scale. PMID:25404036

  11. Electron excitation and autoionisation cross sections for elements of chemically peculiar stars: Study of bismuth

    NASA Astrophysics Data System (ADS)

    Predojević, B.; Pejčev, V.; Šević, D.; Marinković, B. P.

    2014-12-01

    Electron impact excitation from the ground state of bismuth atoms has been studied. A beam of electrons was scattered from a beam of atoms and the intensity of scattered electrons was measured for scattering angles up to 150° and incident electron energies of 40 and 60 eV. Obtained intensities were used for the calculation of relative differential cross sections (DCS). In addition, we recorded the energy loss-spectra at different incident electron energies and scattering angles. These spectra were analysed in order to identify the energy levels of bismuth atom below and above (autoionisation) the first ionization limit in electron spectroscopy. The presence of bismuth was confirmed in spectra of the chemically peculiar (CP) magnetic Ap 73 Dra and HR 465 and nonmagnetic Hg-Mn HR 7775 and χ Lupi stars. The obtained results for relative DCS and identified autoionised energy levels of bismuth were analysed and compared with previous experimental and theoretical data. The connection between our investigations of bismuth and astrophysical measurements are discussed.

  12. Inexpensive laser-induced surface modification in bismuth thin films

    NASA Astrophysics Data System (ADS)

    Contreras, A. Reyes; Hautefeuille, M.; García, A. Esparza; Mejia, O. Olea; López, M. A. Camacho

    2015-05-01

    In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD-DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters.

  13. Bismuth Oxide Thin Films Deposited on Silicon Through Pulsed Laser Ablation, for Infrared Detectors

    NASA Astrophysics Data System (ADS)

    Condurache-Bota, Simona; Constantinescu, Catalin; Tigau, Nicolae; Praisler, Mirela

    2016-12-01

    Infrared detectors are used in many human activities, from industry to military, telecommunications, environmental studies and even medicine. Bismuth oxide thin films have proved their potential for optoelectronic applications, but their uses as infrared sensors have not been thoroughly studied so far. In this paper, pulsed laser ablation of pure bismuth targets within a controlled oxygen atmosphere is proposed for the deposition of bismuth oxide films on Si (100) substrates. Crystalline films were obtained, whose uniformity depends on the deposition conditions (number of laser pulses and the use of a radio-frequency (RF) discharge of the oxygen inside the deposition chamber). The optical analysis proved that the refractive index of the films is higher than 3 and that their optical bandgap is around 1eV, recommending them for infrared applications.

  14. Thin film bismuth iron oxides useful for piezoelectric devices

    DOEpatents

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  15. Bismuth thin films obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Flores, Teresa; Arronte, Miguel; Rodriguez, Eugenio; Ponce, Luis; Alonso, J. C.; Garcia, C.; Fernandez, M.; Haro, E.

    1999-07-01

    In the present work Bi thin films were obtained by Pulsed Laser Deposition, using Nd:YAG lasers. The films were characterized by optical microscopy. Raman spectroscopy and X-rays diffraction. It was accomplished the real time spectral emission characterization of the plasma generated during the laser evaporation process. Highly oriented thin films were obtained.

  16. Spectrographic analysis of bismuth-tin eutectic alloys by spark-ignited low-voltage ac-arc excitation

    NASA Technical Reports Server (NTRS)

    Huff, E. A.; Kulpa, S. J.

    1969-01-01

    Spectrographic method determines individual stainless steel components in molten bismuth-42 w/o tin eutectic to determine the solubility of Type 304 stainless steels. It utilizes the high sensitivity and precision of the spark-ignited, low-voltage ac-arc excitation of samples rendered homogeneous by dissolution.

  17. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi3Fe5O12, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches -5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods.

  18. Bismuth ferrite based thin films, nanofibers, and field effect transistor devices

    NASA Astrophysics Data System (ADS)

    Rivera-Beltran, Rut

    In this research an attempt has been made to explore bismuth ferrite thin films with low leakage current and nanofibers with high photoconductivity. Thin films were deposited with pulsed laser deposition (PLD) method. An attempt has been made to develop thin films under different deposition parameters with following target compositions: i) 0.6BiFeO3-0.4(Bi0.5 K0.5)TiO3 (BFO-BKT) and ii) bi-layered 0.88Bi 0.5Na0.5TiO3-0.08Bi0.5K0.5TiO 3-0.04BaTiO3/BiFeO3 (BNT-BKT-BT/BFO). BFO-BKT thin film shows suppressed leakage current by about four orders of magnitude which in turn improve the ferroelectric and dielectric properties of the films. The optimum remnant polarization is 19 muC.cm-2 at the oxygen partial pressure of 300 mtorr. The BNT-BKT-BT/BFO bi-layered thin films exhibited ferroelectric behavior as: Pr = 22.0 muC.cm-2, Ec = 100 kV.cm-1 and epsilonr = 140. The leakage current of bi-layered thin films have been reduced two orders of magnitude compare to un-doped bismuth ferrite. Bismuth ferrite nanofibers were developed by electrospinning technique and its electronic properties such as photoconductivity and field effect transistor performance were investigated extensively. Nanofibers were deposited by electrospinning of sol-gel solution on SiO2/Si substrate at driving voltage of 10 kV followed by heat treatment at 550 °C for 2 hours. The composition analysis through energy dispersive detector and electron energy loss spectroscopy revealed the heterogeneous nature of the composition with Bi rich and Fe deficient regions. X-ray photoelectron spectroscopy results confirmed the combination of Fe3+ and Fe2+ valence state in the fibers. The photoresponse result is almost hundred times higher for a fiber of 40 nm diameter compared to a fiber with 100 nm diameter. This effect is described by a size dependent surface recombination mechanism. A single and multiple BFO nanofibers field effect transistors devices were fabricated and characterized. Bismuth ferrite FET behaves

  19. Chemically deposited thin films of sulfides and selenides of antimony and bismuth as solar energy materials

    NASA Astrophysics Data System (ADS)

    Nair, M. T.; Nair, Padmanabhan K.; Garcia, V. M.; Pena, Y.; Arenas, O. L.; Garcia, J. C.; Gomez-Daza, O.

    1997-10-01

    Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

  20. Chemical deposition of bismuth selenide thin films using N,N-dimethylselenourea

    NASA Astrophysics Data System (ADS)

    García, V. M.; Nair, M. T. S.; Nair, P. K.; Zingaro, R. A.

    1997-05-01

    Good quality thin films of bismuth selenide of thickness up to 0268-1242/12/5/020/img7 were deposited from solutions containing bismuth nitrate, triethanolamine and N,N-dimethylselenourea maintained at temperatures ranging from room temperature to 0268-1242/12/5/020/img8. X-ray diffraction patterns of the samples annealed at 0268-1242/12/5/020/img9 in air match the standard pattern of hexagonal 0268-1242/12/5/020/img10 (paraguanajuatite, JCPDS 33-0214). The films exhibit strong optical absorption corresponding to a bandgap of about 1.7 - 1.41 eV in the as-prepared films. These values decrease to about 1.57 - 1.06 eV upon annealing the films at 0268-1242/12/5/020/img9 for 1 h in nitrogen. As-deposited, the films show high sheet resistance 0268-1242/12/5/020/img12 in the dark. Annealing the films in air or in nitrogen enhances the dark current by about seven orders of magnitude; the resulting dark conductivity is about 0268-1242/12/5/020/img13. This enhancement in conductivity results from improved crystallinity as well as from partial loss of selenium.

  1. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    NASA Astrophysics Data System (ADS)

    Takashiri, Masayuki; Kurita, Kensuke; Hagino, Harutoshi; Tanaka, Saburo; Miyazaki, Koji

    2015-08-01

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N2 atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H2 (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K2) that of the thin films treated with EB irradiation alone.

  2. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    SciTech Connect

    Takashiri, Masayuki Kurita, Kensuke; Hagino, Harutoshi; Miyazaki, Koji; Tanaka, Saburo

    2015-08-14

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N{sub 2} atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H{sub 2} (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K{sup 2}) that of the thin films treated with EB irradiation alone.

  3. Optical properties of bismuth sulfide thin film prepared by thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Kachari, T.; Rahman, A.

    2015-04-01

    Two types of thin films of Bi2S3 have been prepared on chemically cleaned glass substrate by thermal evaporation technique. Either by thermal evaporation of Bi2S3 powder or by thermal evaporation of bismuth and sulfur from two separate source. (Both annealed for 3 h in air inside an oven). Optical properties of these annealed films have been studied by measuring transmittance, absorbance and reflectance of the films. Optical constants such as absorption coefficient, extinction constants, refractive index, dielectric constants etc. of both types of Bi2S3 films have been calculated. Optical band gap of type (I) and (II) films have been found to be 1.647 and 1.668 eV respectively. The crystalline structure and purity of these Bi2S3 films have been studied by taking X-ray diffraction and X-ray fluorescence spectra. Surface morphology of the films has been studied by scanning electron microscopy.

  4. Effect of annealing atmosphere on phase formation and electrical characteristics of bismuth ferrite thin films

    SciTech Connect

    Simoes, A.Z.; Riccardi, C.S.; Dos Santos, M.L.; Garcia, F. Gonzalez; Longo, E.; Varela, J.A.

    2009-08-05

    Bismuth ferrite thin films were deposited on Pt/Ti/SiO{sub 2}/Si substrates by a soft chemical method and spin-coating technique. The effect of annealing atmosphere (air, N{sub 2} and O{sub 2}) on the structure and electrical properties of the films are reported. X-ray diffraction analysis reveals that the film annealed in air atmosphere is a single-phase perovskite structure. The films annealed in air showed better crystallinity and the presence of a single BFO phase leading to lower leakage current density and superior ferroelectric hysteresis loops at room temperature. In this way, we reveal that BFO film crystallized in air atmosphere by the soft chemical method can be useful for practical applications, including nonvolatile digital memories, spintronics and data-storage media.

  5. Direct evidence for the spin cycloid in strained nanoscale bismuth ferrite thin films

    PubMed Central

    Bertinshaw, Joel; Maran, Ronald; Callori, Sara J.; Ramesh, Vidya; Cheung, Jeffery; Danilkin, Sergey A.; Lee, Wai Tung; Hu, Songbai; Seidel, Jan; Valanoor, Nagarajan; Ulrich, Clemens

    2016-01-01

    Magnonic devices that utilize electric control of spin waves mediated by complex spin textures are an emerging direction in spintronics research. Room-temperature multiferroic materials, such as bismuth ferrite (BiFeO3), would be ideal candidates for this purpose. To realize magnonic devices, a robust long-range spin cycloid with well-known direction is desired, since it is a prerequisite for the magnetoelectric coupling. Despite extensive investigation, the stabilization of a large-scale uniform spin cycloid in nanoscale (100 nm) thin BiFeO3 films has not been accomplished. Here, we demonstrate cycloidal spin order in 100 nm BiFeO3 thin films through the careful choice of crystallographic orientation, and control of the electrostatic and strain boundary conditions. Neutron diffraction, in conjunction with X-ray diffraction, reveals an incommensurate spin cycloid with a unique [11] propagation direction. While this direction is different from bulk BiFeO3, the cycloid length and Néel temperature remain equivalent to bulk at room temperature. PMID:27585637

  6. Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition.

    PubMed

    Jeong, Sang Yun; Choi, Kyoung Soon; Shin, Hye-Min; Kim, Taemin Ludvic; Song, Jaesun; Yoon, Sejun; Jang, Ho Won; Yoon, Myung-Han; Jeon, Cheolho; Lee, Jouhahn; Lee, Sanghan

    2017-01-11

    We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm(2) at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO4 film might further enhance the performance.

  7. Galvanomagnetic properties of thin films of bismuth and bismuth-antimony alloys on substrates with different thermal expansions

    NASA Astrophysics Data System (ADS)

    Grabov, V. M.; Komarov, V. A.; Kablukova, N. S.

    2016-03-01

    Temperature dependences of the galvanomagnetic properties of films of bismuth and Bi100 - x Sb x ( x ≤ 12) on substrates with different temperature expansion coefficients were studied in the temperature range of 77-300 K. The block films were prepared through thermal deposition, and single-crystal Bi100 - x Sb x were grown by zone recrystallization under a coating. It was found that the temperature expansion coefficient of a substrate substantially influenced the galvanomagnetic properties of Bi and Bi100 - x Sb x films. Using the experimental data, the change in the charge-carrier concentration in the Bi and Bi100 - x Sb x films on different substrates at 77 K was estimated.

  8. Mapping strain modulated electronic structure perturbations in mixed phase bismuth ferrite thin films

    SciTech Connect

    Krishnan, P.S. Sanakara R.; Aguiar, Jeffery A.; Ramasse, Q. M.; Kepaptsoglou, D. M.; Liang, W. I.; Chu, Y. H.; Browning, Nigel D.; Munroe, Paul R.; Nagarajan, Valanoor

    2015-01-01

    Strain engineering of epitaxial ferroelectrics has emerged as a powerful method to tailor the electromechanical response of these materials, although the effect of strain at the atomic scale and the interplay between lattice displacements and electronic structure changes are not yet fully understood. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we systematically probe the role of epitaxial strain in mixed phase bismuth ferrite thin films. Electron energy loss O K and Fe L2,3 edge spectra acquired across the rhombohedral (R)-tetragonal (T) phase boundary reveal progressive, and systematic changes, in electronic structure going from one phase to the other. The comparison of the acquired spectra, with theoretical simulations using DFT, suggests a breakage in the structural symmetry across the boundary due to the simultaneous presence of increasing epitaxial strain and off- axial symmetry in the T phase. This implies that the imposed epitaxial strain plays a significant role in not only changing the crystal-field geometry, but also the bonding environment surrounding the central iron cation at the interface thus providing new insights and a possible link to understand how the imposed strain could perturb magnetic ordering in the T phase BFO.

  9. Influence of bismuth substitution on yttrium orthoferrite thin films preparation by the MOD method

    NASA Astrophysics Data System (ADS)

    Galstyan, Ogsen; Lee, Hanju; Park, Jongwon; Lee, Jung-Ha; Babajanyan, Arsen; Friedman, Barry; Lee, Kiejin

    2016-01-01

    Yttrium orthoferrite thin films with a thickness of about 0.4 μm were prepared on glass substrates by using a metal-organic decomposition method. Our studies reveal that it is possible to reduce the crystallization temperature of the yttrium orthoferrite by the substitution of the yttrium ion with bismuth. For the samples BixY1-xFeO3 with x=0.3 and x=0.4, orthorhombic yttrium orthoferrite characteristic peaks in the X-ray diffraction spectra have been detected. The lattice constants of the Bi0.3Y0.7FeO3 film were a=5.905 Å, b=7.66 Å, c=5.256 Å with an average grain size of about 40 nm. The magnetization data indicate that the film has in-plane easy axis and weak coercivity which might be explained by a possible secondary garnet phase crystallization. Faraday rotation angle of the sample was measured to be about 0.3°/μm.

  10. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing.

    PubMed

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-19

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm(-1) K(-2)), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

  11. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing

    NASA Astrophysics Data System (ADS)

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-01

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm-1 K-2), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

  12. Global and Chaotic Dynamics for a Parametrically Excited Thin Plate

    NASA Astrophysics Data System (ADS)

    ZHANG, W.

    2001-02-01

    The global bifurcations and chaotic dynamics of a parametrically excited, simply supported rectangular thin plate are analyzed. The formulas of the thin plate are derived by von Karman-type equation and Galerkin's approach. The method of multiple scales is used to obtain the averaged equations. Based on the averaged equations, theory of normal form is used to give the explicit expressions of normal form associated with a double zero and a pair of pure imaginary eigenvalues by Maple program. On the basis of the normal form, global bifurcation analysis of the parametrically excited rectangular thin plate is given by a global perturbation method developed by Kovacic and Wiggins. The chaotic motion of thin plate is found by numerical simulation.

  13. Comprehensive dielectric performance of bismuth acceptor doped BaTiO3 based nanocrystal thin film capacitors

    SciTech Connect

    Liu, SY; Zhang, HN; Sviridov, L; Huang, LM; Liu, XH; Samson, J; Akins, D; Li, J; O'Brien, S

    2012-11-07

    We present a novel approach to preparing bismuth acceptor doped barium titanate nanocrystal formulations that can be deposited in conjunction with polymers in order to prepare a thin film nanocomposite dielectric that exhibits desirable capacitor characteristics. Exploring the limits of dielectric function in nanocomposites is an important avenue of materials research, while paying strict attention to the overall device quality, namely permittivity, loss and equivalent series resistance (ESR). Pushing capacitor function to higher frequencies, a desirable goal from an electrical engineering point of view, presents a new set of challenges in terms of minimizing interfacial, space charge and polarization effects within the dielectric. We show the ability to synthesize BaTi0.96Bi0.04O3 or BaTi0.97Bi0.03O3 depending on nominal molar concentrations of bismuth at the onset. The low temperature solvothermal route allows for substitution at the titanium site (strongly supported by Rietveld and Raman analysis). Characterization is performed by XRD with Rietveld refinement, Raman Spectroscopy, SEM and HRTEM. A mechanism is proposed for bismuth acceptor substitution, based on the chemical reaction of the alkoxy-metal precursors involving nucleophilic addition. Dielectric analysis of the nanocrystal thin films is performed by preparing nanocrystal/PVP 2-2 nanocomposites (no annealing) and comparing BaTi0.96Bi0.04O3 and BaTi0.97Bi0.03O3 with undoped BaTiO3. Improvements of up to 25% in capacitance (permittivity) are observed, with lower loss and dramatically improved ESR, all to very high frequency ranges (>10 MHz).

  14. Group III-nitride thin films grown using MBE and bismuth

    DOEpatents

    Kisielowski, Christian K.; Rubin, Michael

    2000-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  15. Group III-nitride thin films grown using MBE and bismuth

    DOEpatents

    Kisielowski, Christian K.; Rubin, Michael

    2002-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  16. Evaluation of Specific Heat, Sound Velocity and Lattice Thermal Conductivity of Strained Nanocrystalline Bismuth Antimony Telluride Thin Films

    NASA Astrophysics Data System (ADS)

    Zheng, D.; Tanaka, S.; Miyazaki, K.; Takashiri, M.

    2015-06-01

    To investigate the effect of strain on specific heat, sound velocity and lattice thermal conductivity of nanocrystalline bismuth antimony telluride thin films, we performed both experimental study and modeling. The nanocrystalline thin films had mostly preferred crystal orientation along c-axis, and strains in the both directions of c-axis and a- b-axis. It was found that the thermal conductivity of nanocrystalline thin films decreased greatly as compared with that of bulk alloys. To gain insight into the thermal transport in the strained nanocrystalline thin films, we estimated the lattice thermal conductivity based on the phonon transport model of full distribution of mean free paths accounting for the effects of grain size and strain which was influenced to both the sound velocity and the specific heat. As a result, the lattice thermal conductivity was increased when the strain was shifted from compressive to tensile direction. We also confirmed that the strain was influenced by the lattice thermal conductivity but the reduction of the lattice thermal conductivity of thin films can be mainly attributed to the nano-size effect rather than the strain effect. Finally, it was found that the measured lattice thermal conductivities were in good agreement with modeling.

  17. Bismuth Subsalicylate

    MedlinePlus

    Pink Bismuth® ... Bismuth subsalicylate is used to treat diarrhea, heartburn, and upset stomach in adults and children 12 years of age and older. Bismuth subsalicylate is in a class of medications called ...

  18. Characterization of bismuth selenide (Bi2Se3) thin films obtained by evaporating the hydrothermally synthesised nano-particles

    NASA Astrophysics Data System (ADS)

    Indirajith, R.; Rajalakshmi, M.; Gopalakrishnan, R.; Ramamurthi, K.

    2016-03-01

    Bismuth selenide (Bi2Se3) was synthesized by hydrothermal method at 200 °C and confirmed by powder X-ray diffraction (XRD) studies. The synthesized material was utilized to deposit bismuth selenide thin films at various substrate temperatures (Room Temperature-RT, 150 °C, 250 °C, 350 °C and 450 °C) by electron beam evaporation technique. XRD study confirmed the polycrystalline nature of the deposited Bi2Se3films. Optical transmittance spectra showed that the deposited (at RT) films acquire relatively high average transmittance of 60%in near infrared region (1500-2500 nm). An indirect allowed optical band gap calculated from the absorption edge for the deposited films is ranging from 0.62 to 0.8 eV. Scanning electron and atomic force microscopy analyses reveal the formation of nano-scale sized particles on the surface and that the nature of surface microstructures is influenced by the substrate temperature. Hall measurements showed improved electrical properties, for the films deposited at 350 °C which possess 2.8 times the mobility and 0.9 times the resistivity of the films deposited at RT.

  19. Synthesis and materials chemistry of bismuth tris-(di-i-propylcarbamate): deposition of photoactive Bi2O3 thin films.

    PubMed

    Cosham, Samuel D; Hill, Michael S; Horley, Graeme A; Johnson, Andrew L; Jordan, Laura; Molloy, Kieran C; Stanton, David C

    2014-01-06

    The bismuth carbamate Bi(O2CNPr(i)2)3, a tetramer in the solid-state, has been synthesized and used to deposit mixtures of bismuth oxides by aerosol-assisted chemical vapor deposition (AACVD). The nature of the deposited oxide is a function of both temperature and run-time. Initially, δ-Bi2O3 is deposited, over which grows a thick layer of β-Bi2O3 nanowires, the latter having an increasing degree of preferred orientation at higher deposition temperatures. The photocatalytic activity of a thin film of δ-Bi2O3 for the degradation of methylene blue dye was found to be similar to that of a commercial TiO2 film on glass, while the film overcoated with β-Bi2O3 nanowires was less active. Exposure of Bi(O2CNPr(i)2)3 to controlled amounts of moist air affords the novel oxo-cluster Bi8(O)6(O2CNPr(i)2)12, whose structure has also been determined.

  20. Photophysics, photoelectrical properties and photoconductivity relaxation dynamics of quantum-sized bismuth(III) sulfide thin films

    SciTech Connect

    Pejova, Biljana . E-mail: biljana@iunona.pmf.ukim.edu.mk; Tanusevski, Atanas; Grozdanov, Ivan

    2005-06-15

    Electrical and photoelectrical properties (including both the stationary photoresponse and the photocarriers' relaxation dynamics) of nanocrystalline semiconducting bismuth(III) sulfide thin films were investigated. The experimental design of photoelectrical properties was achieved by controlling the chemistry of the deposition process (varying the reagent concentration in the reaction system) and also by physical means (controlling the crystal dimensions by post-deposition annealing). The band gap energy of thin films characterized by most pronounced photoelectrical properties was calculated, on the basis of measured photoconductivity spectral response curves, by several approaches. All of the obtained values are in very good agreement with the corresponding ones obtained from optical spectroscopy data within the framework of parabolic approximation for dispersion relation. On the basis of measured temperature dependence of dark electrical resistivity of nanocrystalline bismuth(III) sulfide films, the thermal band gap energy and the ionization energy of the impurity level (of donor type) were calculated. The corresponding values are 1.50 and 0.42eV. Dynamics of non-equilibrium charge carriers' relaxation processes was studied with the oscilloscopic method. By analysis of the photoconductivity decay kinetics data it is found that recombination of non-equilibrium charge carriers is carried out according to the linear mechanism. The calculated relaxation time of photoexcited charge carriers is 1.58ms, the relaxation processes occurring via local trapping centers. Recombination processes occurring via a single-type trapping center can be described within the framework of the Schockley-Read model. The practically linear regime detected in the measured lux-ampere characteristics of the studied films ({delta}{sigma}{approx}{phi}{sup 0.98}) indicate as well a linear recombination mechanism of the photoexcited charge carriers.

  1. Determination of the Origin of Crystal Orientation for Nanocrystalline Bismuth Telluride-Based Thin Films Prepared by Use of the Flash Evaporation Method

    NASA Astrophysics Data System (ADS)

    Takashiri, M.; Tanaka, S.; Miyazaki, K.

    2014-06-01

    We have investigated the origin of crystal orientation for nanocrystalline bismuth telluride-based thin films. Thin films of p-type bismuth telluride antimony (Bi-Te-Sb) and n-type bismuth telluride selenide (Bi-Te-Se) were fabricated by a flash evaporation method, with exactly the same deposition conditions except for the elemental composition of the starting powders. For p-type Bi-Te-Sb thin films the main x-ray diffraction (XRD) peaks were from the c-axis (Σ{00l}/Σ{ hkl} = 0.88) whereas n-type Bi-Te-Se thin films were randomly oriented (Σ{00l}/Σ{ hkl} = 0.40). Crystal orientation, crystallinity, and crystallite size were improved for both types of thin film by sintering. For p-type Bi-Te-Sb thin films, especially, high-quality structures were obtained compared with those of n-type Bi-Te-Se thin films. We also estimated the thermoelectric properties of the as-grown and sintered thin films. The power factor was enhanced by sintering; maximum values were 34.9 μW/cm K2 for p-type Bi-Te-Sb thin films at a sintering temperature of 300°C and 23.9 μW/cm K2 for n-type Bi-Te-Se thin films at a sintering temperature of 350°C. The exact mechanisms of film growth are not yet clear but we deduce the crystal orientation originates from the size of nano-clusters generated on the tungsten boat during flash evaporation.

  2. Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron garnet thin films

    NASA Astrophysics Data System (ADS)

    Deb, Marwan; Vomir, Mircea; Rehspringer, Jean-Luc; Bigot, Jean-Yves

    2015-12-01

    Controlling the magnetization dynamics on the femtosecond timescale is of fundamental importance for integrated opto-spintronic devices. For industrial perspectives, it requires to develop simple growth techniques for obtaining large area magneto-optical materials having a high amplitude ultrafast Faraday or Kerr response. Here we report on optical pump probe studies of light induced spin dynamics in high quality bismuth doped iron garnet polycrystalline film prepared by the spin coating method. We demonstrate an ultrafast non-thermal optical control of the spin dynamics using both circularly and linearly polarized pulses.

  3. Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron garnet thin films

    SciTech Connect

    Deb, Marwan Vomir, Mircea; Rehspringer, Jean-Luc; Bigot, Jean-Yves

    2015-12-21

    Controlling the magnetization dynamics on the femtosecond timescale is of fundamental importance for integrated opto-spintronic devices. For industrial perspectives, it requires to develop simple growth techniques for obtaining large area magneto-optical materials having a high amplitude ultrafast Faraday or Kerr response. Here we report on optical pump probe studies of light induced spin dynamics in high quality bismuth doped iron garnet polycrystalline film prepared by the spin coating method. We demonstrate an ultrafast non-thermal optical control of the spin dynamics using both circularly and linearly polarized pulses.

  4. Multiplexed displacement fiber sensor using thin core fiber exciter.

    PubMed

    Chen, Zhen; Hefferman, Gerald; Wei, Tao

    2015-06-01

    This letter reports a multiplexed optical displacement sensor using a thin core fiber (TCF) exciter. The TCF exciter is followed by a stripped single mode optical fiber. A small section of buffer is used as the movable component along the single mode fiber. Ultra-weak cladding mode reflection (< - 75 dB) was employed to probe the refractive index discontinuity between the air and buffer coating boundary. The position change of the movable buffer segment results in a delay change of the cladding mode reflection. Thus, it is a measure of the displacement of the buffer segment with respect to the glass fiber. The insertion loss of one sensor was measured to be less than 3 dB. A linear relationship was evaluated between the measurement position and absolute position of the moving actuator. Multiplexed capability was demonstrated and no cross talk was found between the sensors.

  5. Excitation of Josephson Plasma Resonance in BISMUTH(2) STRONTIUM(2) Calcium COPPER(2) OXYGEN(8+DELTA)

    NASA Astrophysics Data System (ADS)

    Tsui, Ophelia Kwan Chui

    A novel magnetic resonance is observed in Bi_2Sr_2CaCu_2O_{8+ delta} single crystals exposed to microwave radiation (26 to 95 GHz) in the presence of a magnetic field. The resonance exhibits unconventional field and temperature dependence. At a fixed temperature below the melting transition of the vortex solid, T_ {m}(B), the resonance frequency decreases with the applied field and displays a power-law dependence, viz. omega~ B^{-mu }. The exponent was found to be 0.8 within 10% across all samples and temperatures studied. However, when the temperature is increased above T_ {m}(B), mu becomes sample dependent and is equal to 0.64 and 1.08 for the two samples studied. At fixed microwave frequencies, the resonance field, B_0 increases exponentially with temperature to a maximum at T_{m }(B) and decreases slowly with temperature above. We attribute the resonance to Josephson plasma oscillations excited along the sample c-axis. The model explains many features of the experiment. Recently, Bulaevskii et al. proposed an explanation for the field dependence of the Josephson plasma frequency. By assuming that disorder in vortex pancakes is caused by strong pinning at low temperatures, the authors obtained the power-law dependence of omega on B, which agrees with the experiment. Rotating the microwave E-field, { bf E}_{rf} relatively to the sample, we find maximum resonance absorption when {bf E}_{rf} has the maximum projection along the sample c-axis, and minimum when there is none. This identification of {bf E}_{rf} parallel to the sample c-axis as the one responsible for the resonance, supports the Josephson plasma hypothesis. The strongest evidence for the Josephson plasma model is obtained by tilting the magnetic field close to alignment with the ab-plane of the crystal. In that case, an unusual re-entrant cusp in B_0 is observed when the tilt angle is in the range -5.5^circ to 5.5^circ. This is consistent with Bulaevskii et al.'s calculation. They propose that pancake

  6. Determining the Thermal Conductivity of Nanocrystalline Bismuth Telluride Thin Films Using the Differential 3 ω Method While Accounting for Thermal Contact Resistance

    NASA Astrophysics Data System (ADS)

    Kudo, S.; Hagino, H.; Tanaka, S.; Miyazaki, K.; Takashiri, M.

    2015-06-01

    We have estimated the thermal conductivity of nanocrystalline bismuth telluride thin films using the differential 3 ω method, taking into account the thermal contact resistance (TCR) between the substrate and thin-film layers. The thin films were prepared on alumina substrates by radio-frequency (RF) magnetron sputtering at temperature of 200°C. Film thickness varied between 0.8 μm and 3.1 μm. The structural properties of the films were analyzed using x-ray diffraction analysis. Their electrical conductivity, Seebeck coefficient, and power factor were evaluated. For measurement of thermal properties by the differential 3 ω method, SiO2 thin films were deposited onto the samples, to act as insulating layers. Thin aluminum wire was then patterned onto the SiO2 layer. The observed variations in temperature amplitude as a function of film thickness indicated that the TCR contribution was very small and could therefore be neglected when estimating the thermal conductivity of the thin films. The thermal conductivity of the nanocrystalline bismuth telluride thin films with thickness of 0.8 μm and 2.1 μm were determined to be 0.55 W/(m K) and 0.48 W/(m K), respectively.

  7. Spin-torque-driven excitations in magnetic thin films

    NASA Astrophysics Data System (ADS)

    Wang, C.; Seinige, H.; Staudacher, T.; Tsoi, M.

    2011-03-01

    Spin transfer torque (STT) refers to a novel method to control and manipulate magnetic moments using an electrical current. For the past decade it has proven to be a fascinating domain of research with a number of manifestations in various systems interesting both from fundamental science's point of view as well as for technological applications. In ferromagnetic/nonmagnetic (F/N) multilayers a dc electrical current can switch and/or drive its constituent F parts into high-frequency precession which is of interest for microwave and magnetic recording technologies. Interestingly, application of high-frequency currents can also drive the multilayer, e.g., into ferromagnetic resonance (STT-FMR) precession. In our experiments we use point contacts to inject high microwave currents into a variety of magnetic thin films including NiFe/Cu/NiFe/IrMn and NiFe/Cu/Co spin valves, and single ferromagnetic (NiFe or Co) films. The resulting magnetodynamics are detected electrically when a small rectified dc voltage appears across the contact at resonance. We find that in addition to a standard FMR, the microwave currents can excite other resonance modes in our point contacts. We study the behavior of the excitations as a function of applied magnetic field, dc bias current, and microwave frequency. Supported in part by NSF grants DMR-06-45377.

  8. Integration and High-Temperature Characterization of Ferroelectric Vanadium-Doped Bismuth Titanate Thin Films on Silicon Carbide

    NASA Astrophysics Data System (ADS)

    Ekström, Mattias; Khartsev, Sergiy; Östling, Mikael; Zetterling, Carl-Mikael

    2017-03-01

    4H-SiC electronics can operate at high temperature (HT), e.g., 300°C to 500°C, for extended times. Systems using sensors and amplifiers that operate at HT would benefit from microcontrollers which can also operate at HT. Microcontrollers require nonvolatile memory (NVM) for computer programs. In this work, we demonstrate the possibility of integrating ferroelectric vanadium-doped bismuth titanate (BiTV) thin films on 4H-SiC for HT memory applications, with BiTV ferroelectric capacitors providing memory functionality. Film deposition was achieved by laser ablation on Pt (111)/TiO2/4H-SiC substrates, with magnetron-sputtered Pt used as bottom electrode and thermally evaporated Au as upper contacts. Film characterization by x-ray diffraction analysis revealed predominately (117) orientation. P-E hysteresis loops measured at room temperature showed maximum 2P r of 48 μC/cm2, large enough for wide read margins. P-E loops were measurable up to 450°C, with losses limiting measurements above 450°C. The phase-transition temperature was determined to be about 660°C from the discontinuity in dielectric permittivity, close to what is achieved for ceramics. These BiTV ferroelectric capacitors demonstrate potential for use in HT NVM applications for SiC digital electronics.

  9. Efficient water-splitting device based on a bismuth vanadate photoanode and thin-film silicon solar cells.

    PubMed

    Han, Lihao; Abdi, Fatwa F; van de Krol, Roel; Liu, Rui; Huang, Zhuangqun; Lewerenz, Hans-Joachim; Dam, Bernard; Zeman, Miro; Smets, Arno H M

    2014-10-01

    A hybrid photovoltaic/photoelectrochemical (PV/PEC) water-splitting device with a benchmark solar-to-hydrogen conversion efficiency of 5.2% under simulated air mass (AM) 1.5 illumination is reported. This cell consists of a gradient-doped tungsten-bismuth vanadate (W:BiVO4 ) photoanode and a thin-film silicon solar cell. The improvement with respect to an earlier cell that also used gradient-doped W:BiVO4 has been achieved by simultaneously introducing a textured substrate to enhance light trapping in the BiVO4 photoanode and further optimization of the W gradient doping profile in the photoanode. Various PV cells have been studied in combination with this BiVO4 photoanode, such as an amorphous silicon (a-Si:H) single junction, an a-Si:H/a-Si:H double junction, and an a-Si:H/nanocrystalline silicon (nc-Si:H) micromorph junction. The highest conversion efficiency, which is also the record efficiency for metal oxide based water-splitting devices, is reached for a tandem system consisting of the optimized W:BiVO4 photoanode and the micromorph (a-Si:H/nc-Si:H) cell. This record efficiency is attributed to the increased performance of the BiVO4 photoanode, which is the limiting factor in this hybrid PEC/PV device, as well as better spectral matching between BiVO4 and the nc-Si:H cell.

  10. Optical and structural properties of indium doped bismuth selenide thin films

    NASA Astrophysics Data System (ADS)

    Pavagadhi, Himanshu; Vyas, S. M.; Patel, Piyush; Patel, Vimal; Patel, Jaydev; Jani, M. P.

    2015-08-01

    In: Bi2Se3 crystals were grown by Bridgman method at a growth velocity of 0.5cm/h with temperature gradient of 650 C/cm in our laboratory. The thin films of In:Bi2se3 were grown on amorphous substrate (glass) at a room temperature under a pressure of 10-4Pa by thermal evaporation technique. Thin film were deposited at various thicknesses and optical absorption spectrum of such thin films, obtain in wave no. range 300 to 2600 cm-1. The optical energy gap calculated from this data were found to be inverse function of square of thickness, particularly for thickness about 1800 Å or less. This dependence is explained in terms of quantum size effect. For thicker films, the bandgap is found to be independent of film thickness. For the surface stud of the as grown thin film by using AFM, which shows continuous film with some step height and surface roughness found in terms of few nm and particle size varies with respect to thickness.

  11. Optical and structural properties of indium doped bismuth selenide thin films

    SciTech Connect

    Pavagadhi, Himanshu Vyas, S. M. Patel, Piyush; Patel, Vimal; Patel, Jaydev; Jani, M. P.

    2015-08-28

    In: Bi{sub 2}Se{sub 3} crystals were grown by Bridgman method at a growth velocity of 0.5cm/h with temperature gradient of 650 C/cm in our laboratory. The thin films of In:Bi{sub 2}se{sub 3} were grown on amorphous substrate (glass) at a room temperature under a pressure of 10{sup −4}Pa by thermal evaporation technique. Thin film were deposited at various thicknesses and optical absorption spectrum of such thin films, obtain in wave no. range 300 to 2600 cm{sup −1}. The optical energy gap calculated from this data were found to be inverse function of square of thickness, particularly for thickness about 1800 Å or less. This dependence is explained in terms of quantum size effect. For thicker films, the bandgap is found to be independent of film thickness. For the surface stud of the as grown thin film by using AFM, which shows continuous film with some step height and surface roughness found in terms of few nm and particle size varies with respect to thickness.

  12. A new class of room-temperature multiferroic thin films with bismuth-based supercell structure.

    PubMed

    Chen, Aiping; Zhou, Honghui; Bi, Zhenxing; Zhu, Yuanyuan; Luo, Zhiping; Bayraktaroglu, Adrian; Phillips, Jamie; Choi, Eun-Mi; Macmanus-Driscoll, Judith L; Pennycook, Stephen J; Narayan, Jagdish; Jia, Quanxi; Zhang, Xinghang; Wang, Haiyan

    2013-02-20

    Intergrowth of two partially miscible phases of BiFeO(3) and BiMnO(3) gives a new class of room-temperature multiferroic phase, Bi(3) Fe(2) Mn(2) O(10+δ) , which has a unique supercell (SC) structure. The SC heterostructures exhibit simultaneously room-temperature ferrimagnetism and remanent polarization. These results open up a new avenue for exploring room-temperature single-phase multiferroic thin films by controlling the phase mixing of two perovskite BiRO(3) (R = Cr, Mn, Fe, Co, Ni) materials.

  13. Structure, composition and microwave dielectric properties of bismuth zinc niobate pyrochlore thin films

    NASA Astrophysics Data System (ADS)

    Wang, Zhao; Ren, Wei; Zhan, Xuelei; Shi, Peng; Wu, Xiaoqing

    2014-11-01

    (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 (BZN) pyrochlore thin films were deposited onto both Pt/TiO2/SiO2/Si and polycrystalline alumina substrates using pulsed laser deposition technique and then post-annealed using rapid thermal processing. The deposition temperature varies from 300 °C to 600 °C, and all the BZN films showed cubic pyrochlore structure after annealing at 650 °C for 30 min in air. The influence of the substrate associated with crystal structure is significant in the as-deposited films and disappears after post-annealing. The dielectric properties as a function of frequency up to the microwave frequency in both films were measured by LCR meter and split-post dielectric resonator technique. It is found that the BZN film deposited at 400 °C and post-annealed at 650 °C shows excellent dielectric properties with low loss in the microwave frequency range. This result indicates that the BZN thin film is a potential microwave material.

  14. Electric control of magnon frequencies and magnetic moment of bismuth ferrite thin films at room temperature

    PubMed Central

    Kumar, Ashok; Scott, J. F.; Katiyar, R. S.

    2011-01-01

    Here, we report the tuning of room-temperature magnon frequencies from 473 GHz to 402 GHz (14%) and magnetic moment from 4 to 18 emu∕cm3 at 100 Oe under the application of external electric fields (E) across interdigital electrodes in BiFeO3 (BFO) thin films. A decrease in magnon frequencies and increase in phonon frequencies were observed with Magnon and phonon Raman intensities are asymmetric with polarity, decreasing with positive E (+E) and increasing with negative E (−E) where polarity is with respect to in-plane polarization P. The magnetoelectric coupling (α) is proved to be linear and a rather isotropic α = 8.5 × 10−12 sm−1. PMID:21901050

  15. Electric control of magnon frequencies and magnetic moment of bismuth ferrite thin films at room temperature.

    PubMed

    Kumar, Ashok; Scott, J F; Katiyar, R S

    2011-08-08

    Here, we report the tuning of room-temperature magnon frequencies from 473 GHz to 402 GHz (14%) and magnetic moment from 4 to 18 emu∕cm(3) at 100 Oe under the application of external electric fields (E) across interdigital electrodes in BiFeO(3) (BFO) thin films. A decrease in magnon frequencies and increase in phonon frequencies were observed with Magnon and phonon Raman intensities are asymmetric with polarity, decreasing with positive E (+E) and increasing with negative E (-E) where polarity is with respect to in-plane polarization P. The magnetoelectric coupling (α) is proved to be linear and a rather isotropic α = 8.5 × 10(-12) sm(-1).

  16. Magnetic anisotropies in (210)-oriented bismuth substituted iron garnet thin films

    NASA Astrophysics Data System (ADS)

    Nistor, I.; Holthaus, C.; Tkachuk, S.; Mayergoyz, I. D.; Krafft, C.

    2007-05-01

    The liquid phase epitaxy growth and characterization of single crystal (210)-oriented thin garnet films with Bi substitution up to 1.5at./f.u. is reported. These epitaxial films exhibit an easy plane of magnetization which is inclined with respect to the film plane, making them uniquely suitable for garnet-based magneto-optic imagers (MOIs). In order to identify the optimal growth conditions to attain the highest sensitivity of such MOIs, the chemical composition of the films is discussed in relation with their magnetic and optic properties. It has been demonstrated that the increase in the amount of Pr tends to increase the in-plane orthorhombic anisotropy field HKi, while the rare-earth substitution by Bi has a strong effect on the canted orthorhombic anisotropy Kyz. The best MOI film had a saturation field of 130Oe and a sensitivity of 175deg /A.

  17. Superconducting Thin Films of Bismuth-Strontium Calcium-Copper by Laser Ablation

    NASA Astrophysics Data System (ADS)

    Bedekar, Milind Mukund

    The discovery in 1986 of a new class of copper oxide superconductors has led to the development of three major systems that exhibit superconducting properties. Among these systems, the Bi-Sr-Ca-Cu-O superconductors offer intrinsic advantages due to the high T_ {rm c}, chemical inertness and tolerance for a range of compositions. However due to the problems in pure phase formation, thin film research on these materials has progressed more slowly than the other cuprate systems. This dissertation examines the film growth, by laser ablation, of the Bi-Sr-Ca-Cu-O superconductors and the effect of the deposition parameters such as the laser target interaction, substrate temperature, target to substrate distance, deposition and cooling pressure, target type and processing and the substrate type. CO_2 laser ablation was shown to give rise to a non-stoichiometric material transfer due to the low fluences and long pulse lengths. In situ superconducting thin films with T_{ rm c(0)}'s of 76 K could be deposited using the KrF laser at substrate temperatures of 5 ^circC to 20^circ C below melting. Lower temperatures gave rise to a mixture of 2201 and glassy phases. An increase in the target to substrate distance led to a deterioration of the electrical and structural properties of the films due to a decrease in the energy for film formation. A maximum in T_{rm c(0)} was observed at 450 mtorr as the deposition pressure was varied between 200 to 700 mtorr. Optimum oxygen incorporation could be achieved by cooling the films in high oxygen pressures and the best films were obtained with 700 torr cooling pressure. The oxygen deficiency of the hot pressed targets led to inferior properties compared to the conventionally sintered targets. The films displayed FWHM's of 1 ^circ in the omega scan and AFM studies indicated the presence of 1/2 μm grains. The microwave surface resistance of the films measured at 35 GHz showed an onset at 80 K and dropped below that of copper at 30 K. The

  18. Spectroscopic ellipsometry investigations of the optical properties of manganese doped bismuth vanadate thin films

    SciTech Connect

    Kumari, Neelam; Krupanidhi, S.B.; Varma, K.B.R.

    2010-04-15

    The optical properties of Bi{sub 2}V{sub 1-x}Mn{sub x}O{sub 5.5-x} {l_brace}x = 0.05, 0.1, 0.15 and 0.2 at.%{r_brace} thin films fabricated by pulsed laser deposition on platinized silicon substrates were studied in UV-visible spectral region (1.51-4.17 eV) using spectroscopic ellipsometry. The optical constants and thicknesses of these films have been obtained by fitting the ellipsometric data ({Psi} and {Delta}) using a multilayer four-phase model system and a relaxed Lorentz oscillator dispersion relation. The surface roughness and film thickness obtained by spectroscopic ellipsometry were found to be consistent with the results obtained by atomic force and scanning electron microscopy. The refractive index measured at 650 nm does not show any marginal increase with Mn content. Further, the extinction coefficient does not show much decrease with increasing Mn content. An increase in optical band gap energy from 2.52 to 2.77 eV with increasing Mn content from x = 0.05 to 0.15 was attributed to the increase in oxygen ion vacancy disorder.

  19. Carrier confinement and bond softening in photoexcited bismuth films

    NASA Astrophysics Data System (ADS)

    Shin, Taeho; Wolfson, Johanna W.; Teitelbaum, Samuel W.; Kandyla, Maria; Nelson, Keith A.

    2015-11-01

    Femtosecond pump-probe spectroscopy of bismuth thin films has revealed strong dependencies of reflectivity and phonon frequency on film thickness in the range of 25 -40 nm . The reflectivity variations are ascribed to distinct electronic structures originating from strongly varying electronic temperatures and proximity of the film thickness to the optical penetration depth of visible light. The phonon frequency is redshifted by an amount that increases with decreasing film thickness under the same excitation fluence, indicating carrier density-dependent bond softening that increases due to suppressed diffusion of carriers away from the photoexcited region in thin films. The results have significant implications for nonthermal melting of bismuth as well as lattice heating due to inelastic electron-phonon scattering.

  20. Polarization-dependent force driving the Eg mode in bismuth under optical excitation: comparison of first-principles theory with ultra-fast x-ray experiments

    NASA Astrophysics Data System (ADS)

    Fahy, Stephen; Murray, Eamonn

    2015-03-01

    Using first principles electronic structure methods, we calculate the induced force on the Eg (zone centre transverse optical) phonon mode in bismuth immediately after absorption of a ultrafast pulse of polarized light. To compare the results with recent ultra-fast, time-resolved x-ray diffraction experiments, we include the decay of the force due to carrier scattering, as measured in optical Raman scattering experiments, and simulate the optical absorption process, depth-dependent atomic driving forces, and x-ray diffraction in the experimental geometry. We find excellent agreement between the theoretical predictions and the observed oscillations of the x-ray diffraction signal, indicating that first-principles theory of optical absorption is well suited to the calculation of initial atomic driving forces in photo-excited materials following ultrafast excitation. This work is supported by Science Foundation Ireland (Grant No. 12/IA/1601) and EU Commission under the Marie Curie Incoming International Fellowships (Grant No. PIIF-GA-2012-329695).

  1. Excitation of Love waves in a thin film layer by a line source.

    NASA Technical Reports Server (NTRS)

    Tuan, H.-S.; Ponamgi, S. R.

    1972-01-01

    The excitation of a Love surface wave guided by a thin film layer deposited on a semiinfinite substrate is studied in this paper. Both the thin film and the substrate are considered to be elastically isotropic. Amplitudes of the surface wave in the thin film region and the substrate are found in terms of the strength of a line source vibrating in a direction transverse to the propagating wave. In addition to the surface wave, the bulk shear wave excited by the source is also studied. Analytical expressions for the bulk wave amplitude as a function of the direction of propagation, the acoustic powers transported by the surface and bulk waves, and the efficiency of surface wave excitation are obtained. A numerical example is given to show how the bulk wave radiation pattern depends upon the source frequency, the film thickness and other important parameters of the problem. The efficiency of surface wave excitation is also calculated for various parameter values.

  2. Airflow energy harvesters of metal-based PZT thin films by self-excited vibration

    NASA Astrophysics Data System (ADS)

    Suwa, E.; Tsujiura, Y.; Kurokawa, F.; Hida, H.; Kanno, I.

    2014-11-01

    We developed self-excited vibration energy harvesters of Pb(Zr,Ti)O3 (PZT) thin films using airflow. To enhance the self-excited vibration, we used 30-μm-thick stainless steel (SS304) foils as base cantilevers on which PZT thin films were deposited by rf-magnetron sputtering. To compensate for the initial bending of PZT/SS304 unimorph cantilever due to the thermal stress, we deposited counter PZT thin films on the back of the SS304 cantilever. We evaluated power-generation performance and vibration mode of the energy harvester in the airflow. When the angle of attack (AOA) was 20° to 30°, large vibration was generated at wind speeds over 8 m/s. By FFT analysis, we confirmed that stable self-excited vibration was generated. At the AOA of 30°, the output power reached 19 μW at wind speeds of 12 m/s.

  3. Interference effects in the UV(VUV)-excited luminescence spectroscopy of thin dielectric films.

    PubMed

    Buntov, Evgeny; Zatsepin, Anatoly

    2013-05-01

    The problem of exciting UV and VUV light interference affecting experimental photoluminescence excitation spectra is analysed for the case of thin transparent films containing arbitrarily distributed emission centres. A numerical technique and supplied software aimed at modelling the phenomenon and correcting the distorted spectra are proposed. Successful restoration results of the experimental synchrotron data for ion-implanted silica films show that the suggested method has high potential.

  4. Effect of Electronic Excitation on Thin Film Growth

    SciTech Connect

    Elsayed-Ali, Hani E.

    2011-01-31

    The effect of nanosecond pulsed laser excitation on surface diffusion during growth of Ge on Si(100) at 250 degrees C was studied. In Situ reflection high-energy electron diffraction (RHEED) was used to measure the surface diffusion coefficient while ex situ atomic force microscopy (AFM) was used to probe the structure and morphology of the grown quantum dots. The results show that laser excitation of the substrate increases the surface diffusion during growth of Ge on Si(100), changes the growth morphology, improves crystalline structure of the grown quantum dots, and decreases their size distribution. A purely electronic mechanism of enhanced surface diffusion of the deposited Ge is proposed. Ge quantum dots were grown on Si(100)-(2x1) by pulsed laser deposition at various substrate temperatures using a femtosecond Ti:sapphire laser. In-situ reflection high-energy electron diffraction and ex-situ atomic force microscopy were used to analyze the fim structure and morphology. The morphology of germanium islands on silicon was studied at differect coverages. The results show that femtosecond pulsed laser depositon reduces the minimum temperature for epitaxial growth of Ge quantum dots to ~280 degrees C, which is 120 degrees C lower then previously observed in nanosecond pulsed laser deposition and more than 200 degrees C lower than that reported for molecular beam epitaxy and chemical vapor deposition.

  5. Microwave excitation of spin wave beams in thin ferromagnetic films

    PubMed Central

    Gruszecki, P.; Kasprzak, M.; Serebryannikov, A. E.; Krawczyk, M.; Śmigaj, W.

    2016-01-01

    An inherent element of research and applications in photonics is a beam of light. In magnonics, which is the magnetic counterpart of photonics, where spin waves are used instead of electromagnetic waves to transmit and process information, the lack of a beam source limits exploration. Here, we present an approach enabling generation of narrow spin wave beams in thin homogeneous nanosized ferromagnetic films by microwave current. We show that the desired beam-type behavior can be achieved with the aid of a properly designed coplanar waveguide transducer generating a nonuniform microwave magnetic field. We test this idea using micromagnetic simulations, confirming numerically that the resulting spin wave beams propagate over distances of several micrometers. The proposed approach requires neither inhomogeneity of the ferromagnetic film nor nonuniformity of the biasing magnetic field. It can be generalized to different magnetization configurations and yield multiple spin wave beams of different width at the same frequency. PMID:26971711

  6. Wavelength specific excitation of gold nanoparticle thin-films

    NASA Astrophysics Data System (ADS)

    Lucas, Thomas M.; James, Kurtis T.; Beharic, Jasmin; Moiseeva, Evgeniya V.; Keynton, Robert S.; O'Toole, Martin G.; Harnett, Cindy K.

    2014-01-01

    Advances in microelectromechanical systems (MEMS) continue to empower researchers with the ability to sense and actuate at the micro scale. Thermally driven MEMS components are often used for their rapid response and ability to apply relatively high forces. However, thermally driven MEMS often have high power consumption and require physical wiring to the device. This work demonstrates a basis for designing light-powered MEMS with a wavelength specific response. This is accomplished by patterning surface regions with a thin film containing gold nanoparticles that are tuned to have an absorption peak at a particular wavelength. The heating behavior of these patterned surfaces is selected by the wavelength of laser directed at the sample. This method also eliminates the need for wires to power a device. The results demonstrate that gold nanoparticle films are effective wavelength-selective absorbers. This "hybrid" of infrared absorbent gold nanoparticles and MEMS fabrication technology has potential applications in light-actuated switches and other mechanical structures that must bend at specific regions. Deposition methods and surface chemistry will be integrated with three-dimensional MEMS structures in the next phase of this work. The long-term goal of this project is a system of light-powered microactuators for exploring cellular responses to mechanical stimuli, increasing our fundamental understanding of tissue response to everyday mechanical stresses at the molecular level.

  7. Photothermal measurement of absorption and scattering losses in thin films excited by surface plasmons.

    PubMed

    Domené, Esteban A; Balzarotti, Francisco; Bragas, Andrea V; Martínez, Oscar E

    2009-12-15

    We present a novel noncontact, photothermal technique, based on the focus error signal of a commercial CD pickup head that allows direct determination of absorption in thin films. Combined with extinction methods, this technique yields the scattering contribution to the losses. Surface plasmon polaritons are excited using the Kretschmann configuration in thin Au films of varying thickness. By measuring the extinction and absorption simultaneously, it is shown that dielectric constants and thickness retrieval leads to inconsistencies if the model does not account for scattering.

  8. Magnetic, ferroelectric and leakage current properties of gadolinium doped bismuth ferrite thin films by sol-gel method

    NASA Astrophysics Data System (ADS)

    Chen, Hone-Zern; Kao, Ming-Cheng; Young, San-Lin; Hwang, Jun-Dar; Chiang, Jung-Lung; Chen, Po-Yen

    2015-05-01

    Bi0.9Gd0.1FeO3 (BGFO) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by using the sol-gel technology. The effects of annealing temperature (400-700 °C) on microstructure and multiferroic properties of thin films were investigated. The X-ray diffraction analysis showed that the BGFO thin films had an orthorhombic structure. The thin films showed ferroelectric and ferromagnetic properties with remanent polarization (2Pr) of 10 μC/cm2, remnant magnetization (2Mr) of 2.4 emu/g and saturation magnetization (Ms) of 5.3 emu/g. A small leakage current density (J) was 4.64×10-8 A/cm2 under applied field 100 kV/cm. It was found that more than one conduction mechanism is involved in the electric field range used in these experiments. The leakage current mechanisms were controlled by Poole-Frenkel emission in the low electric field region and by Schottky emission from the Pt electrode in the high field region.

  9. Excitation and emission spectra of rubidium in rare-gas thin-films

    NASA Astrophysics Data System (ADS)

    Gerhardt, Ilja; Sin, Kyungseob; Momose, Takamasa

    2012-07-01

    To understand the optical properties of atoms in solid state matrices, the absorption, excitation, and emission spectra of rubidium doped thin-films of argon, krypton, and xenon were investigated in detail. A two-dimensional spectral analysis extends earlier reports on the excitation and emission properties of rubidium in rare-gas hosts. We found that the doped crystals of krypton and xenon exhibit a simple absorption-emission relation, whereas rubidium in argon showed more complicated spectral structures. Our sample preparation employed in the present work yielded different results for the Ar crystal, but our peak positions were consistent with the prediction based on the linear extrapolation of Xe and Kr data. We also observed a bleaching behavior in rubidium excitation spectra, which suggests a population transfer from one to another spectral feature due to hole-burning. The observed optical response implies that rubidium in rare-gas thin-films is detectable with extremely high sensitivity, possibly down to a single atom level, in low concentration samples.

  10. Excitation and emission spectra of rubidium in rare-gas thin-films.

    PubMed

    Gerhardt, Ilja; Sin, Kyungseob; Momose, Takamasa

    2012-07-07

    To understand the optical properties of atoms in solid state matrices, the absorption, excitation, and emission spectra of rubidium doped thin-films of argon, krypton, and xenon were investigated in detail. A two-dimensional spectral analysis extends earlier reports on the excitation and emission properties of rubidium in rare-gas hosts. We found that the doped crystals of krypton and xenon exhibit a simple absorption-emission relation, whereas rubidium in argon showed more complicated spectral structures. Our sample preparation employed in the present work yielded different results for the Ar crystal, but our peak positions were consistent with the prediction based on the linear extrapolation of Xe and Kr data. We also observed a bleaching behavior in rubidium excitation spectra, which suggests a population transfer from one to another spectral feature due to hole-burning. The observed optical response implies that rubidium in rare-gas thin-films is detectable with extremely high sensitivity, possibly down to a single atom level, in low concentration samples.

  11. Excitation and emission spectra of rubidium in rare-gas thin-films

    SciTech Connect

    Gerhardt, Ilja; Sin, Kyungseob; Momose, Takamasa

    2012-07-07

    To understand the optical properties of atoms in solid state matrices, the absorption, excitation, and emission spectra of rubidium doped thin-films of argon, krypton, and xenon were investigated in detail. A two-dimensional spectral analysis extends earlier reports on the excitation and emission properties of rubidium in rare-gas hosts. We found that the doped crystals of krypton and xenon exhibit a simple absorption-emission relation, whereas rubidium in argon showed more complicated spectral structures. Our sample preparation employed in the present work yielded different results for the Ar crystal, but our peak positions were consistent with the prediction based on the linear extrapolation of Xe and Kr data. We also observed a bleaching behavior in rubidium excitation spectra, which suggests a population transfer from one to another spectral feature due to hole-burning. The observed optical response implies that rubidium in rare-gas thin-films is detectable with extremely high sensitivity, possibly down to a single atom level, in low concentration samples.

  12. Resonant indirect excitation of Gd{sup 3+} in AlN thin films

    SciTech Connect

    Ishizu, Yuta; Tsuji, Kazuma; Harada, Yukihiro; Kita, Takashi; Chigi, Yoshitaka; Nishimoto, Tetsuro; Tanaka, Hiroyuki; Kobayashi, Mikihiro; Ishihara, Tsuguo; Izumi, Hirokazu

    2014-05-07

    We studied the efficient indirect excitation of Gd{sup 3+} ions in AlN thin films. C-axis oriented polycrystalline thin films of Al{sub 0.997}Gd{sub 0.003}N/AlN were grown on fused silica substrates using a reactive radio-frequency magnetron sputtering technique. The intra-orbital electron transition in Gd{sup 3+} showed a narrow luminescence line at 3.9 eV. The photoluminescence (PL) excitation (PLE) spectrum exhibited a peak originating from efficient indirect energy transfer from the band edge of AlN to Gd{sup 3+} ions. The PLE peak shifted and the PL intensity showed a dramatic change when the AlN band gap was varied by changing the temperature. Energy scanning performed by changing the band-gap energy of AlN with temperature revealed several resonant channels of energy transfer into the higher excited states of Gd{sup 3+}.

  13. Observation of one magnon and magnon-phonon-electric dipole coupling in multiferroics bismuth ferrite thin films

    NASA Astrophysics Data System (ADS)

    Kumar, Ashok; Murari, N. M.; Katiyar, R. S.

    2008-04-01

    We observed "one magnon," scattering in multiferroic polycrystalline BiFeO3 thin films near 17.2cm-1 at 90K employing Raman spectroscopy. It is seen with a kink in magnon intensity at 150K and with strong anomaly near 210K illustrating spin reorientation transition. The spectral weight of one magnon transferred to the lowest phonon mode near the spin reorientation temperature suggests magnon-phonon coupling. Dielectric constant and dielectric loss as function of temperature showed anomaly at 210K suggesting magnon-phonon-electric dipole coupling. The one magnon becomes overdamped or overcome by elastic scattering at elevated temperatures.

  14. Excitation dependent photoluminescence study of Si-rich a-SiNx:H thin films

    NASA Astrophysics Data System (ADS)

    Kumar Bommali, Ravi; Preet Singh, Sarab; Rai, Sanjay; Mishra, P.; Sekhar, B. R.; Vijaya Prakash, G.; Srivastava, P.

    2012-12-01

    We report photoluminescence (PL) investigations on Si-rich amorphous hydrogenated silicon nitride (a-SiNx:H) thin films of different compositions, using three different excitation lasers, viz., 325 nm, 410 nm, and 532 nm. The as-deposited films contain amorphous Si quantum dots (QDs) as evidenced in high resolution transmission electron microscopy images. The PL spectral shape is in general seen to change with the excitation used, thus emphasizing the presence of multiple luminescence centres in these films. It is found that all the spectra so obtained can be deconvoluted assuming Gaussian contributions from defects and quantum confinement effect. Further strength to this assignment is provided by low temperature (300 °C) hydrogen plasma annealing of these samples, wherein a preferential enhancement of the QD luminescence over defect luminescence is observed.

  15. Experiments on self-excited oscillation in a thin-walled collapsible tube

    NASA Astrophysics Data System (ADS)

    Wu, Hai-Jun; Jia, Lai-Bing; Yin, Xie-Zhen

    2015-12-01

    Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsible tube is developed by using a high transmittance and low Young's modulus silicone rubber tube. The elastic tube is manufactured by the method of centrifugal casting in our laboratory. An optical method for recording the evolution of the cross-sectional areas at a certain position along the longitudinal direction of the tube is developed based on the technology of refractive index matching. With the transparent tube, the tube law is measured under the static no-flow condition. The cross section at the middle position of the tube transfers from a quasi-circular configuration to an ellipse, and then to a dumbell-shape as the chamber pressure is increased. During the self-excited oscillation, two periodic self-excited oscillating states and one transitional oscillating state are identified. They all belong to the LU mode. These different oscillating states are related to the initial cross-sectional shape of the tube caused by the difference of the downstream transmural pressure.

  16. Low-frequency Raman modes and electronic excitations in atomically thin MoS2 films

    NASA Astrophysics Data System (ADS)

    Zeng, Hualing; Zhu, Bairen; Liu, Kai; Fan, Jiahe; Cui, Xiaodong; Zhang, Q. M.

    2012-12-01

    Atomically thin MoS2 crystals have been recognized as quasi-two-dimensional semiconductors with remarkable physical properties. We report our Raman scattering measurements on multilayer and monolayer MoS2, especially in the low-frequency range (<50 cm-1). We find two low-frequency Raman modes with a contrasting thickness dependence. When increasing the number of MoS2 layers, one mode shows a significant increase in frequency while the other decreases following a 1/N (N denotes the number of unit layers) trend. With the aid of first-principles calculations we assign the former as the shear mode E2g2. The latter is distinguished as the compression vibrational mode, similar to the surface vibration of other epitaxial thin films. The opposite evolution of the two modes with thickness demonstrates vibrational modes in an atomically thin crystal as well as a more precise way to characterize the thickness of atomically thin MoS2 films. In addition, we observe a broad feature around 38 cm-1(5 meV) which is visible only under near-resonance excitation and pinned at a fixed energy, independent of thickness. We interpret the feature as an electronic Raman scattering associated with the spin-orbit coupling induced splitting in a conduction band at K points in their Brillouin zone.

  17. Two-dimensional bismuth-rich nanosheets through the evaporative thinning of Se-doped Bi2Te3

    NASA Astrophysics Data System (ADS)

    Hanson, Eve D.; Shi, Fengyuan; Chasapis, Thomas C.; Kanatzidis, Mercouri G.; Dravid, Vinayak P.

    2016-02-01

    High bulk conductance obscures the behavior of surface states in the prototypical topological insulators Bi2Te3 and Bi2Se3. However, ternary phases of Bi2Te3-ySey with balanced donor and acceptor levels may lead to large bulk resistivity, allowing for the observation of the surface states. Additionally, the contribution of the bulk conductance may be further suppressed by nanostructuring, increasing the surface-to-volume ratio. Herein we report the synthesis of a ternary tetradymite newly confined to two dimensions. Ultra-thin large-area stable nanosheets were fabricated via evaporative thinning of a Bi2Te2.9Se0.1 original phase. Owing to vapor pressure differences, a compositional shift to a final Bi-rich phase is observed. The Se/Te ratio of the nanosheet increases tenfold, due to the higher stability of the Bi-Se bonds. Hexagonal crystal symmetry is maintained despite dramatic changes in thickness and stoichiometry. Given that small variations in stoichiometry of this ternary system can incur large changes in carrier concentration and switch majority carrier type, the large compositional shifts found in this case imply that compositional analysis of similar CVD and PVD grown materials is critical to correctly interpret topological insulator performance. Further, the characterization techniques deployed, including STEM-EDS and ToF-SIMS, serve as a case study in determining such compositional shifts in two-dimensional form.

  18. Thin torus perturbative analysis of elementary excitations in the Gaffnian and Haldane-Rezayi quantum Hall states

    NASA Astrophysics Data System (ADS)

    Weerasinghe, Amila; Seidel, Alexander

    2014-09-01

    We present a systematic perturbative approach to study excitations in the thin cylinder/torus limit of the quantum Hall states. The approach is applied to the Haldane-Rezayi and Gaffnian quantum Hall states, which are both expected to have gapless excitations in the usual two-dimensional thermodynamic limit. For the Haldane-Rezayi state, we confirm that gapless excitations are present also in the "one-dimensional" thermodynamic limit of an infinite thin cylinder, in agreement with earlier considerations based on the wave functions alone. In contrast, we identify the lowest excitations of the Gaffnian state in the thin cylinder limit, and conclude that they are gapped, using a combination of perturbative and numerical means. We discuss possible scenarios for the crossover between the two-dimensional and the one-dimensional thermodynamic limit in this case.

  19. Photonic crystal fiber modal interferometer based on thin-core-fiber mode exciter.

    PubMed

    Miao, Yinping; Ma, Xixi; Wu, Jixuan; Song, Binbin; Zhang, Hao; Liu, Bo; Yao, Jianquan

    2015-11-10

    A thin-core-fiber excited photonic crystal fiber modal interferometer has been proposed and experimentally demonstrated. By employing a thin-core fiber as the mode exciter, both of the core and cladding modes propagate in the photonic crystal fiber and interfere with each other. The experimental results show that the transmission dips corresponding to different-order modes have various strain responses with opposite shift directions. The strain sensitivity could be improved to 58.57  pm/με for the applied strain from 0 to 491 με by utilizing the wavelength interval between the dips with opposite shift directions. Moreover, due to the pure silica property of the employed photonic crystal fiber, the proposed fiber modal interferometer exhibits a low-temperature sensitivity of about 0.56  pm/°C within a temperature range from 26.4°C (room temperature) to 70°C. Additionally, the proposed fiber modal interferometer has several advantages, such as good stability, compact structure, and simple fabrication. Therefore, it is more applicable for strain measurement with reducing temperature cross-sensitivity.

  20. Current and potential applications of bismuth-based drugs.

    PubMed

    Keogan, Donal M; Griffith, Darren M

    2014-09-23

    : Bismuth compounds have been used extensively as medicines and in particular for the treatment of gastrointestinal ailments. In addition to bismuth's well known gastroprotective effects and efficacy in treating H. pylori infection it also has broad anti-microbial, anti-leishmanial and anti-cancer properties. Aspects of the biological chemistry of bismuth are discussed and biomolecular targets associated with bismuth treatment are highlighted. This review strives to provide the reader with an up to date account of bismuth-based drugs currently used to treat patients and discuss potential medicinal applications of bismuth drugs with reference to recent developments in the literature. Ultimately this review aims to encourage original contributions to this exciting and important field.

  1. Low-frequency current fluctuations in "graphene-like" exfoliated thin-films of bismuth selenide topological insulators.

    PubMed

    Hossain, Md Zahid; Rumyantsev, Sergey L; Shahil, Khan M F; Teweldebrhan, Desalegne; Shur, Michael; Balandin, Alexander A

    2011-04-26

    We report on the low-frequency current fluctuations and electronic noise in thin-films made of Bi(2)Se(3) topological insulators. The films were prepared via the "graphene-like" mechanical exfoliation and used as the current conducting channels in the four- and two-contact devices. The thickness of the films ranged from ∼50 to 170 nm to avoid hybridization of the top and bottom electron surface states. Analysis of the resistance dependence on the film thickness indicates that the surface contribution to conductance is dominant in our samples. It was established that the current fluctuations have the noise spectrum close to the pure 1/f in the frequency range from 1 Hz to 10 kHz (f is the frequency). The relative noise amplitude S(I)/I(2) for the examined Bi(2)Se(3) films was increasing from ∼5 × 10(-8) to 5 × 10(-6) (1/Hz) as the resistance of the channels varied from ∼10(3) to 10(5) Ω. The obtained noise data is important for understanding electron transport through the surface and volume of topological insulators, and proposed applications of this class of materials. The results may help to develop a new method of noise reduction in electronic devices via the "scattering immune" transport through the surface states.

  2. Excitations in a thin liquid {sup 4}He film from inelastic neutron scattering

    SciTech Connect

    Clements, B.E. |; Godfrin, H.; Krotscheck, E. |; Lauter, H.J.; Leiderer, P.; Passiouk, V. |; Tymczak, C.J.

    1996-05-01

    We perform a thorough analysis of the experimental dynamic structure function measured by inelastic neutron scattering for a low-temperature ({ital T}=0.65 K) four-layer liquid {sup 4}He film. The results are interpreted in light of recent theoretical calculations of the (nonvortex) excitations in thin liquid Bose films. The experimental system consists of four outer liquid layers, adsorbed to two solid inner {sup 4}He layers, which are themselves adsorbed to a graphite substrate. Relatively intense surface (ripplon) and bulklike modes are observed. The analysis of the experimental data gives strong evidence for still other modes and supports the long-standing theoretical predictions of layerlike modes (layer phonons) associated with excitations propagating primarily within the liquid layers comprising the film. The results of the analysis are consistent with the occurrence of level crossings between modes, and the existence of a layer modes for which the theory predicts will propagate in the vicinity of the solid-liquid interface. The theory and experiment agree on the detailed nature of the ripplon; its dispersion at low momenta, its fall off in intensity at intermediate momenta, and the level crossings at high momentum. Similar to experiment, the theory yields an intense mode in the maxon-roton region which is intrepreted as the formation of the bulklike excitation. {copyright} {ital 1996 The American Physical Society.}

  3. A comparative investigation on structure and multiferroic properties of bismuth ferrite thin films by multielement co-doping

    SciTech Connect

    Dong, Guohua; Tan, Guoqiang Luo, Yangyang; Liu, Wenlong; Xia, Ao; Ren, Huijun

    2014-12-15

    Highlights: • Multielement (Tb, Cr and Mn) co-doped BiFeO{sub 3} films were fabricated by CSD method. • Multielement co-doping induces a structural transition. • It is found effective to stabilize the valence of Fe ions at +3 by the strategy. • The co-doping at A/B-sites gives rise to the superior multiferroic properties. - Abstract: (Tb, Cr and Mn) multielement co-doped BiFeO{sub 3} (BTFCMO) thin films were prepared by the chemical solution deposition method on fluorine doped tin oxide (FTO) substrates. X-ray diffraction, Rietveld refinement and Raman analyses revealed that a phase transition from rhombohedral to triclinic structure occurs in the multielement co-doped BiFeO{sub 3} films. It is found that the doping is conducive to stabilizing the valence of Fe ions and reducing leakage current. In addition, the highly enhanced ferroelectric properties with a huge remanent polarization (2P{sub r}) of 239.6 μC/cm{sup 2} and a low coercive field (2E{sub c}) of 615.6 kV/cm are ascribed to the well film texture, the structure transition and the reduced leakage current by the co-doping. Moreover, the structure transition is the dominant factor resulting in the significant enhancement observed in magnetization (M{sub s} ∼ 10.5 emu/cm{sup 3}), owing to the collapse of the space-modulated spin structure. In this contribution, these results demonstrate that the multielement co-doping is in favor of the enhanced multiferroic properties of the BFO films for possible multifunctional applications.

  4. The neutral oxygen spectrum. 1: Collisionally excited level populations and line intensities under optically thin conditions

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Kastner, S. O.

    1995-01-01

    This is the first paper in a projected program to produce quantitative information on the spectrum of the neutral oxygen atom under a variety of excitation conditions. Radiative rates and effective collision strengths are assembled from the recent literature where available, or are calculated for as yet untreated transitions using the University College superstructure/distorted-wave computer package, to produce a complete set of atomic data for a 13 hybrid level model of neutral oxygen. Level populations and relative intensities for 28 allowed, inter-combination, and forbidden oxygen lines are computed, under optically thin conditions, for the electron density range 4.0 less than log N(sub e) less than 12.0 and the electron temperature values T(sub e) = 5000, 10,000, 20,000, 50,000, and 100,000 K. Preliminary applications to observed intercombination/allowed and forbidden/allowed line ratios are discussed.

  5. Dynamics of coupled plasmon polariton wave packets excited at a subwavelength slit in optically thin metal films

    NASA Astrophysics Data System (ADS)

    Wang, Lei-Ming; Zhang, Lingxiao; Seideman, Tamar; Petek, Hrvoje

    2012-10-01

    We study by numerical simulations the excitation and propagation dynamics of coupled surface plasmon polariton (SPP) wave packets (WPs) in optically thin Ag films and a bulk Ag/vacuum interface under the illumination of a subwavelength slit by 400 nm continuous wave (cw) and femtosecond pulsed light. The generated surface fields include contributions from both SPPs and quasicylindrical waves, which dominate in different regimes. We explore aspects of the coupled SPP modes in Ag thin films, including symmetry, propagation, attenuation, and the variation of coupling with incident angle and film thickness. Simulations of the electromagnetic transients initiated with femtosecond pulses reveal new features of coupled SPP WP generation and propagation in thin Ag films. Our results show that, under pulsed excitation, the SPP modes in an Ag thin film break up into two distinct bound surface wave packets characterized by marked differences in symmetries, group velocities, attenuation lengths, and dispersion properties. The nanometer spatial and femtosecond temporal scale excitation and propagation dynamics of the coupled SPP WPs are revealed in detail by movies recording the evolution of their transient field distributions.

  6. The shear-lag effect of thin-walled box girder under vertical earthquake excitation

    NASA Astrophysics Data System (ADS)

    Zhai, Zhipeng; Li, Yaozhuang; Guo, Wei

    2017-03-01

    The variation method based on the energy variation principle is proved to be accurate and valid for analyzing the shear lag effect of box girder under static and dynamic load. Meanwhile, dynamic problems gradually become the key factors in engineering practice. Therefore, a method for calculating the shear lag effect in thin-walled box girder under vertical seismic excitation is proposed by applying Hamilton Principle in this paper. The Timoshenko shear deformation is taken into account. And a new definition of shear lag ratio for box girder is given. What's more, some conclusions are drawn by analysis of numerical example. The results show that small amplitude of earthquake ground motion can generate high stress and obvious shear lag, especially in the region of resonance. And the influence of rotary inertia cannot be ignored for analyzing the shear lag effect. With the increase of span to width ratio, shear lag effect becomes smaller and smaller. These research conclusions will be useful for the engineering practice and enrich the theoretical studies of box girders.

  7. Time-domain excitation of quantized magnetostatic spin-wave modes in patterned NiFe thin film ensembles

    NASA Astrophysics Data System (ADS)

    Crawford, T. M.; Covington, M.; Parker, G. J.

    2003-01-01

    We measure quantized spin waves excited by a spatially inhomogeneous pulsed magnetic field in patterned NiFe thin films by inductive detection of the dynamic magnetization. When anisotropy and numerically calculated demagnetizing fields are included in the magnetostatic Damon Eshbach spin-wave dispersion relation, the predicted mode frequencies agree closely with measurements. Micromagnetic calculations predict the correct mode frequencies and agree remarkably well with time-domain measurements.

  8. Electronic and structural properties of rhombohedral [1 1 1] and [1 1 0] oriented ultra-thin bismuth nanowires.

    PubMed

    Ansari, Lida; Gity, Farzan; Greer, James C

    2017-02-15

    Structures and electronic properties of rhombohedral [1 1 1] and [1 1 0] bismuth nanowires are calculated with the use of density functional theory. The formation of an energy band gap from quantum confinement is studied and to improve estimates for the band gap the GW approximation is applied. The [1 1 1] oriented nanowires require surface bonds to be chemically saturated to avoid formation of metallic surface states, whereas the surfaces of the [1 1 0] nanowires do not support metallic surface states. It is found that the onset of quantum confinement in the surface passivated [1 1 1] nanowires occurs at larger critical dimensions than for the [1 1 0] nanowires. For the [1 1 1] oriented nanowires it is predicted that a band gap of ~0.5 eV can be formed at a diameter of approximately 6 nm, whereas for the [1 1 0] oriented nanowires a diameter of approximately 3 nm is required to achieve a similar band gap energy. The GW correction is also applied to estimates of the electron affinity, ionisation potentials and work functions for both orientations of the nanowires for various diameters below 5 nm. The magnitude of the energy band gaps that arise in bismuth at critical dimensions of a few nanometers are of the same order as for conventional bulk semiconductors.

  9. Electronic and structural properties of rhombohedral [1 1 1] and [1 1 0] oriented ultra-thin bismuth nanowires

    NASA Astrophysics Data System (ADS)

    Ansari, Lida; Gity, Farzan; Greer, James C.

    2017-02-01

    Structures and electronic properties of rhombohedral [1 1 1] and [1 1 0] bismuth nanowires are calculated with the use of density functional theory. The formation of an energy band gap from quantum confinement is studied and to improve estimates for the band gap the GW approximation is applied. The [1 1 1] oriented nanowires require surface bonds to be chemically saturated to avoid formation of metallic surface states, whereas the surfaces of the [1 1 0] nanowires do not support metallic surface states. It is found that the onset of quantum confinement in the surface passivated [1 1 1] nanowires occurs at larger critical dimensions than for the [1 1 0] nanowires. For the [1 1 1] oriented nanowires it is predicted that a band gap of ~0.5 eV can be formed at a diameter of approximately 6 nm, whereas for the [1 1 0] oriented nanowires a diameter of approximately 3 nm is required to achieve a similar band gap energy. The GW correction is also applied to estimates of the electron affinity, ionisation potentials and work functions for both orientations of the nanowires for various diameters below 5 nm. The magnitude of the energy band gaps that arise in bismuth at critical dimensions of a few nanometers are of the same order as for conventional bulk semiconductors.

  10. Fabrication of bright and thin Zn₂SiO₄ luminescent film for electron beam excitation-assisted optical microscope.

    PubMed

    Furukawa, Taichi; Kanamori, Satoshi; Fukuta, Masahiro; Nawa, Yasunori; Kominami, Hiroko; Nakanishi, Yoichiro; Sugita, Atsushi; Inami, Wataru; Kawata, Yoshimasa

    2015-07-13

    We fabricated a bright and thin Zn₂SiO₄ luminescent film to serve as a nanometric light source for high-spatial-resolution optical microscopy based on electron beam excitation. The Zn₂SiO₄ luminescent thin film was fabricated by annealing a ZnO film on a Si₃N₄ substrate at 1000 °C in N₂. The annealed film emitted bright cathodoluminescence compared with the as-deposited film. The film is promising for nano-imaging with electron beam excitation-assisted optical microscopy. We evaluated the spatial resolution of a microscope developed using this Zn₂SiO₄ luminescent thin film. This is the first report of the investigation and application of ZnO/Si₃N₄ annealed at a high temperature (1000 °C). The fabricated Zn₂SiO₄ film is expected to enable high-frame-rate dynamic observation with ultra-high resolution using our electron beam excitation-assisted optical microscopy.

  11. Femtosecond excited-state absorption dynamics and optical limiting in fullerene solutions, sol-gel glasses, and thin films

    SciTech Connect

    McBranch, D.; Klimov, V.; Smilowitz, L.; Wang, H.; Wudl, F.

    1996-11-01

    We compare detailed dynamics of the excited-state absorption for C{sub 60} in solution, thin films, and entrapped in an inorganic sol-gel glass matrix. Our results demonstrate that the microscopic morphology of the C{sub 60} molecule plays a crucial role in determining the relaxation dynamics. This is a key factor for applications in optical limiting for nanosecond pulses using reverse saturable absorption. We find that the dynamics of the C{sub 60}-glass composite occur on long (ns) timescales, comparable to that in solution; thin film samples, by contrast, show rapid decay (<20 picoseconds). These results demonstrate that the C{sub 60}-sol-gel glass composites contain C{sub 60} in a molecular dispersion, and are suitable candidates for solid-state optical limiting. Multispectral analysis of the decay dynamics in solution allows accurate determination of both the intersystem crossing time (600 {+-}100 ps) and the relative strengths of the singlet and triplet excited-state cross sections as a function of wavelength from 450-950 nm. The triplet excited-state cross section is greater than that for the singlet excited-state over the range from 620-810 nm.

  12. Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation.

    PubMed

    Liu, Mingzhao; Nam, Chang-Yong; Zhang, Lihua

    2015-12-21

    Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts.

  13. Phase-matched emission from an optically thin medium following one-photon pulse excitation: Energy considerations

    SciTech Connect

    Berman, P. R.; Le Goueet, J.-L.

    2011-03-15

    Scully and coworkers [M. O. Scully, E. S. Fry, C. H. R. Oii, and K. Wodkiewicz, Phys. Rev. Lett. 96, 010501 (2006)] demonstrated that there is directional, phase-matched emission following the excitation of an ensemble of atoms by a single-photon pulse. While the phase-matched emission intensity is proportional to the the number of atoms, for optically thin samples the total energy emitted in the phase-matched direction is much less than that radiated in other directions. Moreover, even for optically thin samples, it is necessary to take into account effects related to cooperative decay if energy is to be conserved in the overall emission process. An analytic calculation is presented to show explicitly how cooperative decay reduces the incoherent emission and restores energy conservation in this low-density limit.

  14. Terahertz surface emission from Cu2ZnSnSe4 thin film photovoltaic material excited by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Zhao, Zhenyu; Niehues, Gudrun; Funkner, Stefan; Estacio, Elmer; Han, Qifeng; Yamamoto, Kohji; Zhang, Jingtao; Shi, Wangzhou; Guo, Qixin; Tani, Masahiko

    2014-12-01

    We observed efficient terahertz (THz) emission from sol-gel grown Cu2ZnSnSe4 (CZTSe) thin films using THz time domain spectroscopy technique. The THz emission bandwidth exceeds 2 THz with a dynamic range of 20 dB in the amplitude spectrum. The THz emission amplitude from CZTSe is found to be independent of external magnetic fields. Comparing the polarity of THz emission waveforms of CZTSe and GaAs, we suggest that the acceleration of photo-carriers in the surface accumulation layer of CZTSe is the dominant mechanism of radiation emission. Optical excitation fluence dependence measurements show that the saturation fluence of the CZTSe thin film reaches 1.48 μJ/cm2.

  15. Comparison of plasma bismuth levels after oral dosing with basic bismuth carbonate or tripotassium dicitrato bismuthate.

    PubMed

    Madaus, S; Schulte-Frohlinde, E; Scherer, C; Kämmereit, A; Schusdziarra, V; Classen, M

    1992-04-01

    In 20 healthy subjects plasma bismuth concentration was measured after single oral doses of basic bismuth carbonate or tripotassium dicitrato bismuthate. The drugs were administered in the fasted state or immediately after ingestion of a standard breakfast. After basic bismuth carbonate, plasma bismuth rose to concentrations between 0.7 and 2.6 micrograms/L in the fasted state, while after the meal the maximal level was only 1.3 micrograms/L. In contrast to these very low levels after basic bismuth carbonate, the administration of tripotassium dicitrato bismuthate was paralleled by an increase of plasma bismuth to concentrations between 15 and 232 micrograms/L with a mean peak value of 64 +/- 15.3 (S.E.M.) micrograms/L in the fasted state. Postprandial ingestion of tripotassium dicitrato bismuthate attenuated the peak concentrations to 10.9 +/- 6.3 micrograms/L. One subject, however, had a value of 120 micrograms/L. This study demonstrates that basic bismuth carbonate leads to very low plasma bismuth concentrations, which are far below the critical range that might eventually be associated with bismuth neurotoxicity. Therefore this compound can be considered potentially useful for bismuth therapy of gastrointestinal disorders.

  16. Magnetometer uses bismuth-selenide

    NASA Technical Reports Server (NTRS)

    Woollman, J. A.; Spain, I. L.; Beale, H.

    1972-01-01

    Characteristics of bismuth-selenide magnetometer are described. Advantages of bismuth-selenide magnetometer over standard magnetometers are stressed. Thermal stability of bismuth-selenide magnetometer is analyzed. Linearity of output versus magnetic field over wide range of temperatures is reported.

  17. New Approach on Quantification of Porosity of Thin Films via Electron-Excited X-ray Spectra.

    PubMed

    Ortel, Erik; Hertwig, Andreas; Berger, Dirk; Esposito, Pasquale; Rossi, Andrea M; Kraehnert, Ralph; Hodoroaba, Vasile-Dan

    2016-07-19

    One of the crucial characteristics of functionalized thin films is their porosity (i.e., the ratio between the pore volume and the volume of the whole film). Due to the very low amount of material per coated area corresponding to thin films, it is a challenge for analytics to measure the film porosity. In this work, we present an approach to determine the porosity of thin films by means of electron probe microanalysis (EPMA) either by wavelength-dispersive X-ray spectrometry (WDX) or by energy-dispersive X-ray spectrometry (EDX) with a scanning electron microscope (SEM). The procedure is based on the calculation of the film mass deposition from electron-excited X-ray spectra. The mass deposition is converted into film density by division of measured film thickness. Finally, the film porosity is calculated from the measured film density and the density of bulk, nonporous film material. The general applicability of the procedure to determine the porosity is demonstrated on thin templated mesoporous TiO2 films, dip-coated on silicon wafer, with controlled porosity in the range of 15 to 50%. The high accuracy of the mass deposition as determined from X-ray spectra was validated with independent methods (ICP-OES and weighing). Furthermore, for the validation of the porosity results, ellipsometry, interference fringes method (IFM), and focused ion beam (FIB) cross sectioning were employed as independent techniques. Hence, the approach proposed in the present study is proven to be suited as a new analytical tool for accurate and relatively fast determination of the porosity of thin films.

  18. Bismuth compounds in medicinal chemistry.

    PubMed

    Salvador, Jorge A R; Figueiredo, Sandra A C; Pinto, Rui M A; Silvestre, Samuel M

    2012-07-01

    In recent years, the chemical potential of bismuth and bismuth compounds has been actively exploited. Bismuth salts are known for their low toxicity, making them potential valuable reagents for large-scale synthesis, which becomes more obvious when dealing with products such as active pharmaceutical ingredients or synthetic intermediates. Conversely, bismuth compounds have been widely used in medicine. After extensive use in the treatments of syphilis and other bacterial infections before the advent of modern antibiotics, bismuth compounds remain important for the treatment of several gastrointestinal disorders and also exhibit antimicrobial properties and cytotoxic activity, among others. This review updates relevant advances in the past few years, concerning the application of bismuth reagents and catalysts in innovative synthetic processes for the preparation of compounds of medicinal interest, as well as the preparation, biological evaluation and potential medicinal uses of bismuth compounds.

  19. Structural and optical characterization of thermally evaporated bismuth and antimony films for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Srimathy, N.; Ruban Kumar, A.

    2016-05-01

    In this present study, the thin film of bismuth and antimony is coated by thermal evaporation system equipped with the inbuilt ultra high vacuum system. XRD analysis confirmed the rhombohedral structure of Bismuth and Antimony on the prepared film. The surface roughness and physical appearance is analyzed by Atomic force microscopy. The results of Raman Spectroscopy show the wave functions and the spectrum of electrons. The preparation technique and conditions strongly influence the crystalline structure and the phase composition of bismuth and antimony thin films. The electrical and optical properties for the prepared film are analyzed. The results show a great interest and promising applications in Photovoltaic devices.

  20. Electronic excitation induced modifications of optical and morphological properties of PCBM thin films

    NASA Astrophysics Data System (ADS)

    Sharma, T.; Singhal, R.; Vishnoi, R.; Sharma, P.; Patra, A.; Chand, S.; Lakshmi, G. B. V. S.; Biswas, S. K.

    2016-07-01

    Phenyl C61 butyric acid methyl ester (PCBM) is a fullerene derivative and most commonly used in organic photovoltaic devices both as electron acceptor and transporting material due to high electron mobility. PCBM is easy to spin caste on some substrate as it is soluble in chlorobenzene. In this study, the spin coated thin films of PCBM (on two different substrate, glass and double sided silicon) were irradiated using 90 MeV Ni7+ swift heavy ion beam at low fluences ranging from 1 × 109 to 1 × 1011 ions/cm2 to study the effect of ion beam irradiation. The pristine and irradiated PCBM thin films were characterized by UV-visible absorption spectroscopy and fourier transform infrared spectroscopy (FTIR) to investigate the optical properties before and after irradiation. These thin films were further analyzed using atomic force microscopy (AFM) to investigate the morphological modifications which are induced by energetic ions. The variation in optical band gap after irradiation was measured using Tauc's relation from UV-visible absorption spectra. A considerable change was observed with increasing fluence in optical band gap of irradiated thin films of PCBM with respect to the pristine film. The decrease in FTIR band intensity of C60 cage reveals the polymerization reaction due to high energy ion impact. The roughness is also found to be dependent on incident fluences. This study throws light for the application of PCBM in organic solar cells in form of ion irradiation induced nanowires of PCBM for efficient charge carrier transportation in active layer.

  1. Femtosecond to nanosecond excited state dynamics of vapor deposited copper phthalocyanine thin films.

    PubMed

    Caplins, Benjamin W; Mullenbach, Tyler K; Holmes, Russell J; Blank, David A

    2016-04-28

    Vapor deposited thin films of copper phthalocyanine (CuPc) were investigated using transient absorption spectroscopy. Exciton-exciton annihilation dominated the kinetics at high exciton densities. When annihilation was minimized, the observed lifetime was measured to be 8.6 ± 0.6 ns, which is over an order of magnitude longer than previous reports. In comparison with metal free phthalocyanine (H2Pc), the data show evidence that the presence of copper induces an ultrafast relaxation process taking place on the ca. 500 fs timescale. By comparison to recent time-resolved photoemission studies, this is assigned as ultrafast intersystem crossing. As the intersystem crossing occurs ca. 10(4) times faster than lifetime decay, it is likely that triplets are the dominant excitons in vapor deposited CuPc films. The exciton lifetime of CuPc thin films is ca. 35 times longer than H2Pc thin films, while the diffusion lengths reported in the literature are typically quite similar for the two materials. These findings suggest that despite appearing to be similar materials at first glance, CuPc and H2Pc may transport energy in dramatically different ways. This has important implications on the design and mechanistic understanding of devices where phthalocyanines are used as an excitonic material.

  2. Nonlinear vibrations of thin arbitrarily laminated composite plates subjected to harmonic excitations using DKT elements

    NASA Technical Reports Server (NTRS)

    Chiang, C. K.; Xue, David Y.; Mei, Chuh

    1993-01-01

    A finite element formulation is presented for determining the large-amplitude free and steady-state forced vibration response of arbitrarily laminated anisotropic composite thin plates using the Discrete Kirchhoff Theory (DKT) triangular elements. The nonlinear stiffness and harmonic force matrices of an arbitrarily laminated composite triangular plate element are developed for nonlinear free and forced vibration analyses. The linearized updated-mode method with nonlinear time function approximation is employed for the solution of the system nonlinear eigenvalue equations. The amplitude-frequency relations for convergence with gridwork refinement, triangular plates, different boundary conditions, lamination angles, number of plies, and uniform versus concentrated loads are presented.

  3. Non-local dynamics of weakly nonlinear spin excitations in thin ferromagnetic films

    NASA Astrophysics Data System (ADS)

    Kiseliev, V. V.; Tankeyev, A. P.

    1996-12-01

    Effective integro-differential equations of weakly nonlinear dynamics describing the interaction of quasi-one-dimensional exchange-dipole spin-waves are derived for a thin ferromagnetic slab (film). The non-local part of the magnetostatic dispersion of these waves has been taken into account. Algebraic soliton-like states have been predicted. The conditions of their existence and their dynamic properties are investigated depending on the film thickness and on the magnitude and orientation of the external magnetic field. The role of crystallographic magnetic anisotropy in the formation of these states is analysed.

  4. Ultrafast broadband spectroscopy of crystalline bismuth

    SciTech Connect

    Mel'nikov, A A; Misochko, Oleg V; Chekalin, Sergei V

    2013-04-30

    Femtosecond spectroscopy in the wavelength range 0.4 - 2.3 {mu}m has been used to probe ultrafast electronic and lattice processes in bismuth. The photoresponse of a bismuth crystal is shown to comprise components with relaxation times of 1 ps, 7 ps, and {approx}1 ns. The electron-hole and electron-phonon interaction strengths in bismuth are found to depend significantly on the wave vector in the {Gamma}-T direction of the Brillouin zone. Comparison of the spectral dependences of the amplitudes of coherent E{sub g} and A{sub 1g} phonons and the corresponding dependences of the Raman scattering cross sections indicates that these phonon modes differ in generation mechanism. The generation of coherent A{sub 1g} phonons is mainly due to displacement of the equilibrium position of atoms in the crystal lattice in a nonequilibrium state. This process differs fundamentally from resonance Raman scattering responsible for the coherent excitation of low-symmetry phonon modes. (extreme light fields and their applications)

  5. THORIUM DISPERSION IN BISMUTH

    DOEpatents

    Bryner, J.S.

    1961-07-01

    The growth of thorium bismutaide particles, which are formed when thorium is suspended in liquid bismuth, is inhibited when the liquid metal suspension is being flowed through a reactor and through a heat exchanger in sequence. It involves the addition of as little as 1 part by weight of tellurium to 100 parts of thorium. This addition is sufficient to inhibit particle growth and agglomeration.

  6. Characterization of bismuth nanospheres deposited by plasma focus device

    SciTech Connect

    Ahmad, M.; Al-Hawat, Sh.; Akel, M.; Mrad, O.

    2015-02-14

    A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.

  7. Third order nonlinear optical properties of bismuth zinc borate glasses

    SciTech Connect

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.

    2013-12-28

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

  8. Determination of refractive index, extinction coefficient and thickness of thin films by the method of waveguide mode excitation

    SciTech Connect

    Sokolov, V I; Marusin, N V; Panchenko, V Ya; Savelyev, A G; Seminogov, V N; Khaydukov, E V

    2013-12-31

    We propose a method for measuring simultaneously the refractive index n{sub f}, extinction coefficient m{sub f} and thickness H{sub f} of thin films. The method is based on the resonant excitation of waveguide modes in the film by a TE- or a TM-polarised laser beam in the geometry of frustrated total internal reflection. The values of n{sub f}, m{sub f} and H{sub f} are found by minimising the functional φ = [N{sup -1}Σ{sup N}{sub i=1}(R{sub exp}(θ{sub i}) – R{sub thr}(θ{sub i})){sup 2}]{sup 1/2}, where R{sub exp}(θ{sub i}) and R{sub thr}(θ{sub i}) are the experimental and theoretical coefficients of reflection of the light beam from the interface between the measuring prism and the film at an angle of incidence θ{sub i}. The errors in determining n{sub f}, m{sub f} and H{sub f} by this method are ±2 × 10{sup -4}, ±1 × 10{sup -3} and ±0.5%, respectively. (fiber and integrated optics)

  9. Bismuth ochers from San Diego Co., California

    USGS Publications Warehouse

    Schaller, W.T.

    1911-01-01

    The chief points brought out in this paper may be briefly summarized as follows: (1) The existence of natural Bi2O3 has not been established. (2) Natural bismite or bismuth ocher, when pure, is more probably a bismuth hydroxide. (3) The bismuth ochers from San Diego County, California, are either a bismuth hydroxide or bismuth vanadate, pucherite, or mixtures of these two. (4) Pucherite has been found noncrystallin and determined for the first time in the United States.

  10. Bismuth accumulates in the body during treatment with tripotassium dicitrato bismuthate.

    PubMed

    Gavey, C J; Szeto, M L; Nwokolo, C U; Sercombe, J; Pounder, R E

    1989-02-01

    Bismuth concentration was measured in plasma, dried leucocytes and urine in nine patients before, during and after treatment with tripotassium dicitrato bismuthate (De-Noltab 2 b.d.) for 6 weeks. During treatment there was an 8.5-fold rise in median plasma bismuth concentration (P less than 0.01), a non-significant doubling of leucocyte bismuth content, and a 349-fold rise in 24-h urinary bismuth excretion (P less than 0.01). The significantly increased urinary bismuth excretion continued for at least 3 months after cessation of treatment with tripotassium dicitrato bismuthate, indicating accumulation of bismuth during treatment with this drug.

  11. Energetics of bismuth vanadate

    SciTech Connect

    Nagabhushana, G.P.; Tavakoli, A.H.; Navrotsky, A.

    2015-05-15

    Bismuth vanadate has gained considerable interest as a photoanode for water splitting reactions under visible light. It exists in four different polymorphs, out of which three of them have been synthesized. Thermodynamic properties of these three polymorphs are investigated using high temperature oxide melt solution calorimetry. The monoclinic scheelite phase which exhibits photocatalytic activity under visible light is found to be the most stable polymorph, followed by tetragonal scheelite which exhibits activity under UV light. The photocatalytically inactive tetragonal zircon form is found to be the least stable polymorph. The small difference in enthalpy of formation between the two scheelite structures (−8 kJ/mol) is in accord with the reversibility of the transformation between them and the larger difference between the most stable monoclinic phase and the least stable tetragonal zircon phase (−23 kJ/mol) is in accord with the irreversible (monoclinic→tetragonal zircon) phase transformation. - Graphical abstract: Schematic representation of polymorphic transitions in BiVO{sub 4} along with their formation enthalpies. - Highlights: • Bismuth vanadate crystallizes in three different polymorphs. • High temperature calorimetric measurements were made to determine their formation enthalpies. • Enthalpy of formation decreases in the order BV-ms→BV-ts→BV-tz. • Photocatalytically active monoclinic-BiVO{sub 4} was found to be the most stable polymorph.

  12. Plasmonic excitation-assisted optical and electric enhancement in ultra-thin solar cells: the influence of nano-strip cross section

    SciTech Connect

    Sabaeian, Mohammad Heydari, Mehdi; Ajamgard, Narges

    2015-08-15

    The effects of Ag nano-strips with triangle, rectangular and trapezoid cross sections on the optical absorption, generation rate, and short-circuit current density of ultra-thin solar cells were investigated. By putting the nano-strips as a grating structure on the top of the solar cells, the waveguide, surface plasmon polariton (SPP), and localized surface plasmon (LSP) modes, which are excited with the assistance of nano-strips, were evaluated in TE and TM polarizations. The results show, firstly, the TM modes are more influential than TE modes in optical and electrical properties enhancement of solar cell, because of plasmonic excitations in TM mode. Secondly, the trapezoid nano-strips reveal noticeable impact on the optical absorption, generation rate, and short-circuit current density enhancement than triangle and rectangular ones. In particular, the absorption of long wavelengths which is a challenge in ultra-thin solar cells is significantly improved by using Ag trapezoid nano-strips.

  13. Luminescence quenching of Dy3+ ions in lead bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Pisarski, Wojciech A.; Pisarska, Joanna; Lisiecki, Radosław; Dominiak-Dzik, Grażyna; Ryba-Romanowski, Witold

    2012-04-01

    Luminescence of lead bismuthate glasses PbO-Bi2O3-Ga2O3 containing Dy3+ ions has been studied. Two overlapping luminescence bands corresponding to 3P1-1S0 transition of Bi3+ and 4F9/2 -6H13/2 transition of Dy3+ were detected under 480 nm excitation. Comparison of luminescence features for the system under study to those reported for dysprosium-doped lead borate glass PbO-B2O3-Ga2O3 indicates that the luminescence of Dy3+ is efficiently quenched by Bi3+ ions. Analysis of luminescence dynamics implies that the excitation energy transfer from Dy3+ to Bi3+ is nonradiative. The theoretical calculations using Inokuti-Hirayama model confirm strong luminescence of Dy3+ ions in lead bismuthate glasses.

  14. Energetics of bismuth vanadate

    NASA Astrophysics Data System (ADS)

    Nagabhushana, G. P.; Tavakoli, A. H.; Navrotsky, A.

    2015-05-01

    Bismuth vanadate has gained considerable interest as a photoanode for water splitting reactions under visible light. It exists in four different polymorphs, out of which three of them have been synthesized. Thermodynamic properties of these three polymorphs are investigated using high temperature oxide melt solution calorimetry. The monoclinic scheelite phase which exhibits photocatalytic activity under visible light is found to be the most stable polymorph, followed by tetragonal scheelite which exhibits activity under UV light. The photocatalytically inactive tetragonal zircon form is found to be the least stable polymorph. The small difference in enthalpy of formation between the two scheelite structures (-8 kJ/mol) is in accord with the reversibility of the transformation between them and the larger difference between the most stable monoclinic phase and the least stable tetragonal zircon phase (-23 kJ/mol) is in accord with the irreversible (monoclinic→tetragonal zircon) phase transformation.

  15. Gold-bismuth clusters.

    PubMed

    Martínez, Ana

    2014-08-07

    Metal clusters have interesting characteristics, such as the relationship between properties and size of the cluster. This is not always apparent, so theoretical studies can provide relevant information. In this report, optimized structures and electron donor-acceptor properties of AunBim clusters are reported (n + m = 2-7, 20). Density functional theory calculations were performed to obtain optimized structures. The ground states of gold clusters formed with up to seven atoms are planar. The presence of Bi modifies the structure, and the clusters become 3-D. Several optimized geometries have at least one Bi atom bonded to gold or bismuth atoms and form structures similar to NH3. This fragment is also present in clusters with 20 atoms, where the formation of Au3Bi stabilizes the structures. Bismuth clusters are better electron donors and worse electron acceptors than gold clusters. Mixed clusters fall in between these two extremes. The presence of Bi atoms in gold clusters modifies the electron donor-acceptor properties of the clusters, but there is no correlation between the number of Bi atoms present in the cluster and the capacity for donating electrons. The effect of planarity in Au19Bi clusters is the same as that in Au20 clusters. The properties of pure gold clusters are certainly interesting, but clusters formed by Bi and Au are more important because the introduction of different atoms modifies the geometry, the stability, and consequently the physical and chemical properties. Apparently, the presence of Bi may increase the reactivity of gold clusters, but further studies are necessary to corroborate this hypothesis.

  16. Inclusive measurement of (p,. pi. /sup -/xn) double charge exchange reactions on bismuth from threshold to 800 MeV

    SciTech Connect

    Dombsky, M.; D'Auria, J.M.; Kelson, I.; Yavin, A.I.; Ward, T.E.; Clark, J.L.; Ruth, T.; Sheffer, G.

    1985-07-01

    The energy dependence of the total angle-integrated cross section for the production of astatine isotopes from (p,..pi../sup -/xn) double charge exchange reactions on bismuth (/sup 209/Bi) was measured from 120 to 800 MeV using activation and radiochemical techniques. Chemical yields were estimated by direct radioassaying of /sup 211/At activity in thin (approx.1 mg/cm/sup 2/), irradiated bismuth targets. Calculations of the contributions of secondary (two-step) reactions to these measured astatine yields were performed, based partially upon the observed /sup 211/At activity although even at the highest energies, the contribution to products lighter than /sup 207/At was negligible. These data for products with as many as seven neutrons removed from the doubly coherent product (/sup 210/At) display nearly Gaussian shapes for the mass distributions of the astatine residues, with the maximum occurring for about /sup 204/At. The most probable momentum transfer deduced from these distributions for the initial ..pi../sup -/ production step was 335 MeV/c. The observed excitation functions display a behavior similar to that observed for the yield of /sup 210/Po from a (p,..pi../sup 0/) reaction on /sup 209/Bi, but radically different from that observed for inclusive ..pi../sup -/ reactions on a heavy nucleus. These data are discussed in terms of recent theoretical approaches to negative pion production from bismuth. In addition, a simple, schematic model is developed to treat the rapidly decreasing percentage of the total inclusive ..pi../sup -/ emission which is observed for this double charge exchange reaction. This model reflects the opacity of a nucleus to a source of internal energetic protons.

  17. STM driven modification of bismuth nanostructures

    NASA Astrophysics Data System (ADS)

    Kowalczyk, P. J.; Mahapatra, O.; Brown, S. A.; Bian, G.; Chiang, T.-C.

    2014-03-01

    The tip of a scanning tunneling microscope (STM) gently interacting with the substrate is used to modify (110) bismuth islands deposited on highly oriented pyrolitic graphite (HOPG), and hence to investigate the atomic and electronic structure of the islands. The tip interaction leads to the evolution of metastable 3 ML thick regions into structures of higher thermodynamic stability, which in the case of bismuth on graphite are rods (typically ≥ 5 ML high) and stripes. The formation of trenches that extend along the stripes is observed which is related to the presence of kinks and weak bonds at the 3-5 ML interface. Migration of whole islands along particular substrate directions is evidence for superlubricity due to the misfit between Bi and HOPG unit cells. Perimeter diffusion through atoms and not vacancies is a driving force of all observed modifications. The Bi islands are found to be able to deform and their decay is not governed by Ostwald ripening (which is absent in this system). Instead quantum size effects play a major role in the evolution of the islands, as evidenced by the observation of preferred widths. Density functional theory calculations reveal an oval Fermi surface with de Broglie wavelength corresponding to observed width of islands. These results are all consistent with a thin film Bi allotrope which has both paired atomic layers on the surface and bulk-like chains of bonds vertically through the structure.

  18. [Spectroscopic properties of Er3+-doped germanium bismuthate glass].

    PubMed

    Zhang, Yong; Ren, Guo-Zhong; Yang, Qi-Bin; Xu, Chang-Fu; Liu, Yun-Xin; Shang, Zhen-Gang

    2008-05-01

    Er(3+)-Doped Germanium Bismuthate Glass was fabricated and characterized. The absorption spectrum and up-conversion spectrum of glass were studied. The Judd-Oflet intensity parameters omega(t) (t = 2, 4, 6), determined based on Judd-Ofelt theory, were found to be omega2 = 3.35 x 10(-20) cm2, omega4 = 1.34 x 10(-20) cm2, omega6 = 0.67 x 10(-20) cm2. Frequency up-conversion of Er(3+)-doped germanium bismuthate glass has been investigated. The up-conversion mechanisms are discussed under 808 nm and 980 nm excitation. Stimulated emission cross-section of 4I(13/2) --> 4I(15/2) transition was calculated by McCumber theory. Compared to other host glasses, the emission property of Er(3+)-doped germanium bismuthate glasses has advantage over those of silicate, phosphate and germinate glasses. Er(3+)-doped germanium bismuth glasses are promising upconversion optical and optic-communication materials.

  19. Mineral resource of the month: bismuth

    USGS Publications Warehouse

    Carlin Jr., James F.

    2006-01-01

    Bismuth compounds are most known for their soothing effects on the stomach, wounds and sores. These properties make the compounds an essential part of many medicinal and cosmetic preparations, which until 1930 accounted for about 90 percent of the bismuth used. The subsequent development of low-melting alloys and chemical catalysts containing bismuth, as well as its use as an additive to casting alloys, has resulted in a wider variety of industrial applications for bismuth.

  20. 21 CFR 73.1162 - Bismuth oxychloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Bismuth oxychloride. 73.1162 Section 73.1162 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1162 Bismuth oxychloride. (a) Identity. (1) The color additive bismuth oxychloride is a synthetically prepared white or nearly white amorphous or...

  1. 21 CFR 73.1162 - Bismuth oxychloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Bismuth oxychloride. 73.1162 Section 73.1162 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1162 Bismuth oxychloride. (a) Identity. (1) The color additive bismuth oxychloride is a synthetically prepared white or nearly white amorphous or...

  2. 21 CFR 73.1162 - Bismuth oxychloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Bismuth oxychloride. 73.1162 Section 73.1162 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1162 Bismuth oxychloride. (a) Identity. (1) The color additive bismuth oxychloride is a synthetically prepared white or nearly white amorphous or...

  3. Exciting transition metal doped dilute magnetic thin films: MgO:Er and ZnO:Er

    NASA Astrophysics Data System (ADS)

    Ćakıcı, T.; Sarıtaş, S.; Muǧlu, G. Merhan; Yıldırım, M.

    2017-02-01

    Erbium doped MgO and doped ZnO thin films have reasonably important properties applications in spintronic devices. These films were synthesized on glass substrates by Chemical Spray Pyrolysis (CSP) method. In the literature there has been almost no report on preparation of MgO:Er dilute magnetic thin films by means of CSP. Because doped thin films show different magnetic behaviors, depending upon the type of magnetic material ions, concentration of them, synthesis route and experimental conditions, synthesized MgO:Er and ZnO:Er films were compared to thin film properties. Optical analyses of the synthesized thin films were examined spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Structural analysis of the thin films was examined by using XRD, Raman Analysis, FE-SEM, EDX and AFM techniques. Also, magnetic properties of the MgO:Er and ZnO:Er films were investigated by vibrating sample magnetometer (VSM) which show that diamagnetic behavior of the MgO:Er thin film and ferromagnetic (FM) behavior of the ZnO:Er film were is formed.

  4. Terahertz surface emission from Cu{sub 2}ZnSnSe{sub 4} thin film photovoltaic material excited by femtosecond laser pulses

    SciTech Connect

    Zhao, Zhenyu Han, Qifeng; Zhang, Jingtao; Shi, Wangzhou; Niehues, Gudrun; Funkner, Stefan; Yamamoto, Kohji; Tani, Masahiko; Estacio, Elmer; Guo, Qixin

    2014-12-08

    We observed efficient terahertz (THz) emission from sol-gel grown Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films using THz time domain spectroscopy technique. The THz emission bandwidth exceeds 2 THz with a dynamic range of 20 dB in the amplitude spectrum. The THz emission amplitude from CZTSe is found to be independent of external magnetic fields. Comparing the polarity of THz emission waveforms of CZTSe and GaAs, we suggest that the acceleration of photo-carriers in the surface accumulation layer of CZTSe is the dominant mechanism of radiation emission. Optical excitation fluence dependence measurements show that the saturation fluence of the CZTSe thin film reaches 1.48 μJ/cm{sup 2}.

  5. D-penicillamine does not increase urinary bismuth excretion in patients treated with tripotassium dicitrato bismuthate.

    PubMed

    Nwokolo, C U; Pounder, R E

    1990-10-01

    Twenty-four urinary bismuth excretion was measured in five patients who had been treated with tripotassium dicitrato bismuthate, before and after single 1 g oral dose of D-penicillamine. Before dosing with D-penicillamine, the median 24 h urinary bismuth output was 55 micrograms 24 h-1 (range 17-156 micrograms 24 h-1) and following dosing with D-penicillamine the median 24 h urinary bismuth output was 53 micrograms 24 h-1 (range 12-156 micrograms 24 h-1). D-penicillamine does not facilitate the urinary excretion of bismuth, hence it is unsuitable for use as an oral chelator in patients with bismuth intoxication.

  6. Enhancement of optical absorption in thin-film solar cells through the excitation of higher-order nanoparticle plasmon modes.

    PubMed

    Akimov, Yu A; Koh, W S; Ostrikov, K

    2009-06-08

    Recent research in the rapidly emerging field of plasmonics has shown the potential to significantly enhance light trapping inside thin-film solar cells by using metallic nanoparticles. In this article it is demonstrated the plasmon enhancement of optical absorption in amorphous silicon solar cells by using silver nanoparticles. Based on the analysis of the higher-order surface plasmon modes, it is shown how spectral positions of the surface plasmons affect the plasmonic enhancement of thin-film solar cells. By using the predictive 3D modeling, we investigate the effect of the higher-order modes on that enhancement. Finally, we suggest how to maximize the light trapping and optical absorption in the thin-film cell by optimizing the nanoparticle array parameters, which in turn can be used to fine tune the corresponding surface plasmon modes.

  7. The minimum inhibitory concentrations of various bismuth salts against Campylobacter pylori.

    PubMed

    Vogt, K; Warrelmann, M; Hahn, H

    1989-09-01

    The minimum inhibitory concentrations of five bismuth salts (bismuth subcitrate, bismuth subgallate, bismuth subnitrate, bismuth subsalicylate and tripotassium dicitrato bismuthate, a water soluble compound of bismuth subcitrate) were assayed against 48 strains of Campylobacter pylori employing the agar dilution method. Tripotassium dicitrato bismuthate was most effective (MIC50 8 mg/l), the other bismuth salts exhibited somewhat lower inhibitory activities. It is concluded that bismuth salts are suitable agents for inhibiting growth of Campylobacter pylori.

  8. Pharmacokinetics of bismuth and ranitidine following single doses of ranitidine bismuth citrate

    PubMed Central

    KOCH, K M; DAVIS, I M; GOODING, A E; YIN, Y

    1996-01-01

    The pharmacokinetics of bismuth and ranitidine derived from ranitidine bismuth citrate given in single oral doses ranging from 200 mg to 1600 mg were evaluated in healthy subjects. Bismuth was only minimally absorbed (<0.5% of the amount dosed) after administration of ranitidine bismuth citrate, and peak plasma concentrations never exceeded 33 ng ml−1 in any subject. Plasma concentrations and urinary recoveries of bismuth at doses up to and including 800 mg were relatively constant and not proportional to dose. Bismuth absorption was increased more than proportionally with the dose at 1600 mg. The pharmacokinetics of ranitidine after administration of ranitidine bismuth citrate were dose-proportional and consistent with previous observations for ranitidine administered alone. Ranitidine bismuth citrate was well-tolerated in single oral doses of up to 1600 mg. PMID:8864318

  9. SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

    DOEpatents

    Watt, G.W.

    1958-08-19

    An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

  10. Aspects of the magmatic geochemistry of bismuth

    USGS Publications Warehouse

    Greenland, L.P.; Gottfried, D.; Campbell, E.Y.

    1973-01-01

    Bismuth has been determined in 74 rocks from a differentiated tholeiitic dolerite, two calc-alkaline batholith suites and in 66 mineral separates from one of the batholiths. Average bismuth contents, weighted for rock type, of the Great Lake (Tasmania) dolerite, the Southern California batholith and the Idaho batholith are, 32, 50 and 70 ppb respectively. All three bodies demonstrate an enrichment of bismuth in residual magmas with magmatic differentiation. Bismuth is greatly enriched (relative to the host rock) in the calcium-rich accessory minerals, apatite and sphene, but other mineral analyses show that a Bi-Ca association is of little significance to the magmatic geochemistry of bismuth. Most of the bismuth, in the Southern California batholith at least, occurs in a trace mineral phase (possibly sulfides) present as inclusions in the rock-forming minerals. ?? 1973.

  11. Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials.

    PubMed

    Stefik, Morgan

    2016-07-07

    The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO4 . A selective etching process was used with vanadium-rich depositions to enable the synthesis of phase-pure BiVO4 after spinodal decomposition. BiVO4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode using a hole-scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting.

  12. Pure and strong red photoluminescence from Na0.5Gd0.5TiO3: Eu ferroelectric thin films under ultraviolet light excitation

    NASA Astrophysics Data System (ADS)

    Gao, Feng; Sun, Lina; Tan, Jun; Li, Xinsheng; Liu, Dongyun; Liang, Duoqiang

    2017-02-01

    A series of novel photoluminescent ferroelectric thin films Na0.5Gd0.5TiO3: xEu (NGT: Eu) with various Eu3+ doping concentrations were prepared at various heat-treated temperature, which have single pseudo-cubic perovskite structure at proper heat-treated temperature from 700 °C to 800 °C according to X-ray diffraction results. There existed narrow and intensive emission bands located at red light region ascribed to 5D0 → 7F2 and 5D0 → 7F1 transitions of Eu3+ by 283 nm excitation. The strong energy absorption of NGT host and efficient energy transfer to Eu3+ should be primarily responsible for the emissions. Gd3+ acts as sensitizer which has an important role on the energy transfer from the host NGT to Eu3+. The luminescence from NGT: 0.25Eu thin films is the strongest for all the NGT: Eu films, and its color coordinate is (0.65, 0.32) close to ideal red light. The quenching concentration in NGT: Eu films reaches as high as 25%. The lifetime of emissive energy level Eu3+: 5D0 in NGT: 0.1Eu and NGT: 0.5Eu thin films is 1.024 ms and 0.931 ms, respectively. Finally, the ferroelectric property of NGT: 0.25Eu thin films was tested and the remanent polarization (2Pr) is 7.10 μC/cm2 lower than that of Na0.5Bi0.5TiO3.

  13. Producing bismuth trioxide and its application in fire assaying

    NASA Astrophysics Data System (ADS)

    Kelly, Zack; Ojebuoboh, Funsho

    2002-04-01

    Bismuth trioxide (Bi2O3) is the prevalent commercial oxide of bismuth. A precursor to the preparation of other compounds of bismuth, including the chemical reagents, bismuth trioxide has specialized uses in optical glass, flame-retardant paper, and, increasingly, in glaze formulations where it substitutes for lead oxides. In the last decade, bismuth trioxide has also become a key ingredient in flux formulations used by mineral analysts in fire assaying. The production of bismuth trioxide generally begins with the minor metal bismuth. This paper describes bismuth trioxide production and the properties and basis for its use in environmentally sound fire assaying.

  14. Multi-elemental bio-imaging of rat tissue from a study investigating the bioavailability of bismuth from shotgun pellets.

    PubMed

    Urgast, Dagmar S; Ellingsen, Dag G; Berlinger, Balázs; Eilertsen, Einar; Friisk, Grete; Skaug, Vidar; Thomassen, Yngvar; Beattie, John H; Kwun, In-Sook; Feldmann, Jörg

    2012-07-01

    In recent years, bismuth has been promoted as a "green element" and is used as a substitute for the toxic lead in ammunition and other applications. However, the bioavailability and toxicity of bismuth is still not very well described. Following a hunting accident with bismuth-containing shots, a bioavailability study of bismuth from metal pellets inoculated into rat limb muscles was carried out. Bismuth could be found in urine and blood of the animals. Bio-imaging using laser ablation ICP-MS of thin sections of the tissue around the metal implant was carried out to find out more about the distribution of the metal diffusing into the tissue. Two laser ablation systems with different ablation cell designs were compared regarding their analytical performance. Low concentrations of bismuth showing a non-symmetrical pattern were detected in the tissue surrounding the metal implant. This was partly an artefact from cutting the thin sections but also bio-mobilisation of the metals of the implant could be seen. An accumulation of zinc around the implant was interpreted as a marker of inflammation. Challenges regarding sample preparation for laser ablation and bio-imaging of samples of diverse composition became apparent during the analysis.

  15. BISMUTH PHOSPHATE CARRIER PROCESS FOR Pu RECOVERY

    DOEpatents

    Finzel, T.G.

    1959-02-01

    An improvement in the bismuth phosphate carrier precipitation process for recovering plutonium is described. It has been found that a more granular and more easily filterable carrier precipitiite is formed if the addition of the bismuth and phosphate ions is effected by first adding 9/10 of the bismuth ions necessary, then slowly adding all of the source of the phosphate ions to be incorporated in the precipitate, while digesting at 75 C and afterwards incorporating the remainder of the total bismuth ions necessary

  16. Hydrothermal synthesis of bismuth germanium oxide

    SciTech Connect

    Boyle, Timothy J.

    2016-12-13

    A method for the hydrothermal synthesis of bismuth germanium oxide comprises dissolving a bismuth precursor (e.g., bismuth nitrate pentahydrate) and a germanium precursor (e.g., germanium dioxide) in water and heating the aqueous solution to an elevated reaction temperature for a length of time sufficient to produce the eulytite phase of bismuth germanium oxide (E-BGO) with high yield. The E-BGO produced can be used as a scintillator material. For example, the air stability and radioluminescence response suggest that the E-BGO can be employed for medical applications.

  17. Ultrafast carrier dynamics in polycrystalline bismuth telluride nanofilm

    SciTech Connect

    Jia, Lin; Ma, Weigang; Zhang, Xing

    2014-06-16

    In this study, the dynamics of energy carriers in polycrystalline bismuth telluride nanofilm are investigated by the ultrafast pump-probe method. The energy relaxation processes are quantitatively analyzed by using the numerical fitting models. The extracted hot carrier relaxation times of photon excitation, thermalization, and diffusion are around sub-picosecond. The initial reflectivity recovery is found to be dominantly determined by the carrier diffusion, electron-phonon coupling, and photo-generated carriers trapping processes. High-frequency and low-frequency oscillations are both observed and attributed to coherent optical phonons and coherent acoustic phonons, respectively.

  18. Optical transitions and frequency upconversion emission of Er 3+ions in novel lead-bismuthate glass

    NASA Astrophysics Data System (ADS)

    Sun, Hongtao; Dai, Shixun; Zhang, Debao; Xu, Shiqing; Zhang, Junjie; Hu, Lili; Jiang, Zhonghong

    2004-12-01

    Er 3+-doped strontiam lead bismuth glass for developing upconversion lasers has been fabricated and characterized. The Judd-Ofelt analysis was performed on the absorption spectrum and the transition probabilities, excited state lifetimes, and the fluorescence branching ratios were calculated and discussed. Under 975 nm excitation, intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H→4I, 4S→4I, and 4F→4I, respectively, were observed. The upconversion mechanisms are discussed based on the energy matching and quadratic dependence on excitation power, and the dominant mechanisms are excited state absorption and energy transfer upconversion for the green and red emissions.

  19. Hydrothermal synthesis of sodium bismuth titanate and titanate nanofibers

    NASA Astrophysics Data System (ADS)

    Kundu, Animesh

    A hydrothermal processing method was developed for the synthesis of sodium bismuth titanate powders and thin films from suitable precursors at 150°C. Oxide precursors were best suited for preparing pure phase materials. The sodium bismuth titanate powders consisted of cube shaped crystals. A modified solution-reprecitation model involving partial dissolution of the precursors was proposed to explain the growth of these particles. The thin films were prepared on strontium titanate (100) substrate. A sample holder was specially designed and fabricated to secure the substrates in the reaction vessel. The result was a relatively smooth film of thickness ≤550 nm. The films were essentially single crystalline and had strong epitaxial relationship with the substrate. Titanate nanofibers (NaxH yTinO2n+1° zH2O) were known to form under similar hydrothermal conditions as sodium bismuth titanate powders. Detail research revealed that the pure hydroxide and oxide precursors tend to form sodium bismuth titanate powders or thin films. Titanate nanofibers were the predominant product when any other ions or organics were present in the precursor. Much faster reaction kinetics for the formation of nanofibers was observed when certain organic compounds were added deliberately with the precursors. Accordingly, a hydrothermal process was developed for converting the precursors to titanate nanofibers in a significantly shorter time than reported in the literature. A thin film consisting of vertically aligned nanofibers was prepared on titanium substrate at 150°C in as little as 30 minutes. Complete conversion of starting precursors to free standing nanofibers was achieved in ˜8 hours at 150°C. The as-prepared nanofibers were some form of sodium titanate. They were converted to hydrogen titanate by ion exchange. Differential Scanning calorimetric experiments were performed to understand the thermal evolution of the fibers. The hydrogen titanate fibers underwent structural

  20. The absorption of bismuth from oral doses of tripotassium dicitrato bismuthate.

    PubMed

    Nwokolo, C U; Gavey, C J; Smith, J T; Pounder, R E

    1989-02-01

    Two studies measured plasma concentrations of bismuth during dosing with tripotassium dicitrato bismuthate (De-Noltab). The first study compared 24 h plasma bismuth concentration and urinary bismuth excretion in six patients who had already received 29-131 days (median 47 days) of treatment with De-Noltab 2 b.d., and six healthy subjects who only received De-Noltab 2 b.d. on the day of study. There was a prompt rise in plasma bismuth concentration after each dose of De-Noltabs. The median 24 h integrated plasma bismuth concentration was similar in both groups, but the median 24 h urinary bismuth excretion was 5.4-fold higher in the patients. The second study compared the plasma bismuth concentrations after the first and third doses of De-Noltab 2 b.d. in 16 healthy subjects. The median peak bismuth concentration occurred 30 min (range 15-105 min) post-dosing. The peak plasma bismuth concentration was greater than 50 ng/ml in 14 of the 16 subjects, and greater than 100 ng/ml in nine of the subjects. There was no significant difference in the median integrated 10-h plasma bismuth concentration after the first or third dose of De-Noltabs. The results of these studies confirm that bismuth is absorbed and sequestrated during dosing with De-Noltabs. Bismuth is absorbed rapidly after oral dosing with De-Noltabs, to produce peak plasma bismuth concentrations hitherto considered to be in the range associated with bismuth neurotoxicity.

  1. Electronic excitations and structure of Li{sub 2}IrO{sub 3} thin films grown on ZrO{sub 2}:Y (001) substrates

    SciTech Connect

    Jenderka, Marcus Schmidt-Grund, Rüdiger; Grundmann, Marius; Lorenz, Michael

    2015-01-14

    Thin films are a prerequisite for application of the emergent exotic ground states in iridates that result from the interplay of strong spin-orbit coupling and electronic correlations. We report on pulsed laser deposition of Li{sub 2}IrO{sub 3} films on ZrO{sub 2}:Y (001) single crystalline substrates. X-ray diffraction confirms preferential (001) and (10-1) out-of-plane crystalline orientations with well defined in-plane orientation. Resistivity between 35 and 300 K is dominated by a three-dimensional variable range hopping mechanism. The dielectric function is determined by means of spectroscopic ellipsometry and, complemented by Fourier transform infrared transmission spectroscopy, reveals a small optical gap of ≈300 meV, a splitting of the 5d-t{sub 2g} manifold, and several in-gap excitations attributed to phonons and possibly magnons.

  2. Optical orientation of azo dye molecules in a thin solid film upon nonlinear excitation by femtosecond laser pulses

    SciTech Connect

    Yongseok, Jung; Kozenkov, V M; Magnitskiy, Sergey A; Nagorskiy, Nikolay M

    2006-11-30

    The orientation of molecules in an amorphous pure azo dye film upon nonlinear excitation is detected for the first time. The simultaneous increase and decrease in the film transmission by a factor of 2.5 for orthogonal polarisations of probe radiation indicated the appearance of orientation order in the film caused by the reorientation of azo dye molecules. Due to a high photostability of the AD-1 azo dye demonstrated in single-photon experiments and a high efficiency of nonlinear orientation obtained in experiments with femtosecond pulses, this dye can be widely used in three-dimensional nanophotonic devices such as photonic crystals, optical computers, and optical memory. (letters)

  3. In vitro cytotoxicity of surface modified bismuth nanoparticles.

    PubMed

    Luo, Yang; Wang, Chaoming; Qiao, Yong; Hossain, Mainul; Ma, Liyuan; Su, Ming

    2012-10-01

    This paper describes in vitro cytotoxicity of bismuth nanoparticles revealed by three complementary assays (MTT, G6PD, and calcein AM/EthD-1). The results show that bismuth nanoparticles are more toxic than most previously reported bismuth compounds. Concentration dependent cytotoxicities have been observed for bismuth nanoparticles and surface modified bismuth nanoparticles. The bismuth nanoparticles are non-toxic at concentration of 0.5 nM. Nanoparticles at high concentration (50 nM) kill 45, 52, 41, 34 % HeLa cells for bare nanoparticles, amine terminated bismuth nanoparticles, silica coated bismuth nanoparticles, and polyethylene glycol (PEG) modified bismuth nanoparticles, respectively; which indicates cytotoxicity in terms of cell viability is in the descending order of amine terminated bismuth nanoparticles, bare bismuth nanoparticles, silica coated bismuth nanoparticles, and PEG modified bismuth nanoparticles. HeLa cells are more susceptible to toxicity from bismuth nanoparticles than MG-63 cells. The simultaneous use of three toxicity assays provides information on how nanoparticles interact with cells. Silica coated bismuth nanoparticles can damage cellular membrane yet keep mitochondria less influenced; while amine terminated bismuth nanoparticles can affect the metabolic functions of cells. The findings have important implications for caution of nanoparticle exposure and evaluating toxicity of bismuth nanoparticles.

  4. Pharmacokinetics of bismuth and ranitidine following multiple doses of ranitidine bismuth citrate

    PubMed Central

    KOCH, K M; KERR, B M; GOODING, A E; DAVIS, I M

    1996-01-01

    The pharmacokinetics of bismuth and ranitidine derived from oral doses of ranitidine bismuth citrate 800 mg given twice daily for 28 days were examined in this double-blind, placebo-controlled, parallel-group study in 27 healthy subjects. Bismuth accumulation in plasma reflected its multicompartmental disposition, achieving the majority of predicted steady state within 14–28 days. Bismuth absorption from ranitidine bismuth citrate is limited (<0.5% of the dose), and bismuth elimination is predominantly renal secretion. Peak plasma concentrations did not exceed 19 ng ml−1, remaining well below those associated with bismuth toxicity. Bismuth was measurable at low concentrations in plasma and urine for up to 5 months after the last dose. Plasma bismuth concentration-time data and urinary excretion data were best described by separate multicompartmental models, with terminal half-lives averaging 21 days and 45 days, respectively. The pharmacokinetics of ranitidine derived from ranitidine bismuth citrate were similar to those of ranitidine administered alone. Ranitidine did not appreciably accumulate in plasma. Ranitidine bismuth citrate was well-tolerated during 28 days of repeated dosing. PMID:8864319

  5. Local optical emission spectroscopy of excited species effused from an evaporation cell and a sputter source into dense plasmas - Basic studies for the deposition of thin gradient films.

    PubMed

    Bolt, H; Hemel, V; Koch, F; Nickel, H

    1996-06-01

    Space resolved optical emission spectroscopy has been applied to determine the distribution of excited species in dense plasmas which are used for the deposition of thin coatings. Typical electron densities and electron temperatures in the plasma facility PETRA ( Plasma Engineering and Technology Research Assembly) are in the range of n(e) = 10(12) cm(-3) and T(e) = 10 eV. During the deposition process material (Al) is evaporated from a vapour cell under controlled conditions. The vapour stream is guided into a dense plasma which is composed of inert gas, Ar or He, and hydrocarbon species produced from the dissociation of C(2)H(2). The evaporated Al-stream which travels with thermal velocity into a plasma of high electron density, is nearly completely ionized due to the short mean free path for electron impact ionization in the above mentioned parameter range. Optical emission spectroscopy has been applied to investigate the interaction processes between the vapour stream and the plasma as well as the transport of the ionized Al along the applied magnetic field. For the measurements space resolved optical emission spectroscopy with an in-situ translation mechanism of the optical fibre has been used to measure the local concentrations of excited Al neutrals and ions as well as the concentration of the background plasma species.

  6. Variational Photocarrier Radiometry Reconstruction of Exciton Lifetime Spectra for a Coupled PbS Colloidal Quantum Dot Thin Film Under Combined AC and DC Laser Excitation

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Mandelis, Andreas; Melnikov, Alexander

    2015-06-01

    Colloidal quantum dots (CQDs) have attracted significant interest for applications in electronic and optoelectronic devices such as photodetectors, light emitting diodes, and solar cells. However, a poor understanding of charge transport in these nanocrystalline films hinders their practical applications. The photocarrier radiometry (PCR) technique, a frequency-domain photoluminescence method spectrally gated for radiative recombination photon emissions and exclusion of thermal infrared photons, has been applied to a coupled PbS CQD thin film with inter-dot spacing of 0.5 nm to 1 nm for the analysis of charge transport properties. As the nanoparticle bandgap depends on the size of the quantum dots, polydispersity of the CQD thin film causes bandgap variability leading to photoexcited carrier (exciton) decay lifetime broadening and temperature dependence. The carrier transport mechanisms of QDs are quite different from bulk semiconductors, so the conventional carrier-diffusion wave-based PCR theory was modified into a non-diffusive limit model. A developed variational discrete lifetime reconstruction approach was used to analyze PCR frequency scans under two optical excitation modes: a modulated laser source without, and with, an additional continuous laser source. Using this model, the CQD mean lifetime values were found and variational discrete lifetime spectra were reconstructed.

  7. 21 CFR 73.1162 - Bismuth oxychloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1162 Bismuth oxychloride. (a) Identity. (1) The color additive bismuth oxychloride is a synthetically prepared white or nearly white amorphous or finely crystalline, odorless powder consisting principally of BiOCl. (2) Color additive mixtures for drug use...

  8. 21 CFR 73.2162 - Bismuth oxychloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2162 Bismuth oxychloride. (a) Identity and specifications. (1) The color additive bismuth oxychloride shall conform in identity and specifications to...

  9. 21 CFR 73.1162 - Bismuth oxychloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1162 Bismuth oxychloride. (a) Identity. (1) The color additive bismuth oxychloride is a synthetically prepared white or nearly white amorphous or finely crystalline, odorless powder consisting principally of BiOCl. (2) Color additive mixtures for drug use...

  10. Bismuth generator method

    DOEpatents

    Bray, Lane Allan; DesChane, Jaquetta R.

    1998-01-01

    A method for separating .sup.213 Bi from a solution of radionuclides wherein the solution contains a concentration of the chloride ions and hydrogen ions adjusted to allow the formation of a chloride complex. The solution is then brought into contact with an anion exchange resin, whereupon .sup.213 Bi is absorbed from the solution and adhered onto the anion exchange resin in the chloride complex. Other non-absorbing radionuclides such as .sup.225 Ra, .sup.225 Ac, and .sup.221 Fr, along with HCl are removed from the anion exchange resin with a scrub solution. The .sup.213 Bi is removed from the anion exchange resin by washing the anion exchange resin with a stripping solution free of chloride ions and with a reduced hydrogen ion concentration which breaks the chloride anionic complex, releasing the .sup.213 Bi as a cation. In a preferred embodiment of the present invention, the anion exchange resin is provided as a thin membrane, allowing for extremely rapid adherence and stripping of the .sup.213 Bi. A preferred stripping solution for purification of .sup.213 Bi for use in medical applications includes sodium acetate, pH 5.5. A protein conjugated with bifunctional chelating agents in vivo with the NaOAc, to receive the .sup.213 Bi as it is being released from the anion exchange resin.

  11. Bismuth generator method

    DOEpatents

    Bray, L.A.; DesChane, J.R.

    1998-05-05

    A method is described for separating {sup 213}Bi from a solution of radionuclides wherein the solution contains a concentration of the chloride ions and hydrogen ions adjusted to allow the formation of a chloride complex. The solution is then brought into contact with an anion exchange resin, whereupon {sup 213}Bi is absorbed from the solution and adhered onto the anion exchange resin in the chloride complex. Other non-absorbing radionuclides such as {sup 225}Ra, {sup 225}Ac, and {sup 221}Fr, along with HCl are removed from the anion exchange resin with a scrub solution. The {sup 213}Bi is removed from the anion exchange resin by washing the anion exchange resin with a stripping solution free of chloride ions and with a reduced hydrogen ion concentration which breaks the chloride anionic complex, releasing the {sup 213}Bi as a cation. In a preferred embodiment of the present invention, the anion exchange resin is provided as a thin membrane, allowing for extremely rapid adherence and stripping of the {sup 213}Bi. A preferred stripping solution for purification of {sup 213}Bi for use in medical applications includes sodium acetate, pH 5.5. A protein conjugated with bifunctional chelating agents in vivo with the NaOAc receives the {sup 213}Bi as it is being released from the anion exchange resin. 10 figs.

  12. IR luminescence in bismuth-doped germanate glasses and fibres

    SciTech Connect

    Pynenkov, A A; Firstov, Sergei V; Panov, A A; Firstova, E G; Nishchev, K N; Bufetov, Igor' A; Dianov, Evgenii M

    2013-02-28

    We have studied the optical properties of lightly bismuth doped ({<=}0.002 mol %) germanate glasses prepared in an alumina crucible. The glasses are shown to contain bismuth-related active centres that have been identified previously only in bismuth-doped fibres produced by MCVD. With increasing bismuth concentration in the glasses, their luminescence spectra change markedly, which is attributable to interaction between individual bismuth centres. (optical fibres)

  13. Revealing bismuth oxide hollow nanoparticle formation by the Kirkendall effect.

    PubMed

    Niu, Kai-Yang; Park, Jungwon; Zheng, Haimei; Alivisatos, A Paul

    2013-01-01

    We study the formation of bismuth oxide hollow nanoparticles by the Kirkendall effect using liquid cell transmission electron microscopy (TEM). Rich dynamics of bismuth diffusion through the bismuth oxide shell have been captured in situ. The diffusion coefficient of bismuth through bismuth oxide shell is 3-4 orders of magnitude higher than that of bulk. Observation reveals that defects, temperature, sizes of the particles, and so forth can affect the diffusion of reactive species and modify the kinetics of the hollowing process.

  14. Bismuth toxicity in man II. Review of bismuth blood and urine levels in patients after administration of therapeutic bismuth formulations in relation to the problem of bismuth toxicity in man.

    PubMed

    Serfontein, W J; Mekel, R

    1979-11-01

    A survey of the leterature on bismuth toxicity in man in relation to blood level data, has revealed the necessity of distinguishing between lipid soluble and water soluble organic complexes of bismuth on the one hand and the simple inorganic salts of bismuth on the other hand. A characteristic feature of the former, illustrated by the water soluble bismuth complex triglycollamate, is the high bismuth levels (due to absorption of the complex as such) and the nephrotoxic properties of the compound in man. Bismuth absorption after administration of the simple inorganic salts of bismuth is postulated to occur in the form of ionic bismuth as such, low bismuth levels being characteristic features of such compounds. Bismuth blood and urine levels obtained from patients after administration of a new anti-ulcer drug (Bicitropeptide) in a well controlled clinical trial are discussed and suggest that that this bismuth containing drug behaves pharmacologically in a manner similar to the inorganic bismuth salts in man, low bismuth blood levels and the absence of toxic side effects being conspicuous features of the drug. Based on these considerations, it is proposed that the pharmacologically active bismuth compounds be divided into four different groups depending on structure, stability and solubility. The question as to what constitutes a "toxic bismuth blood level" can only be discussed in relation to the new proposed sub-division of bismuth compounds and is only meaningful if the term is defined to relate only to ionic bismuth (presumably bound to a large extent to blood proteins). Based on information gleaned from the literature and blood level values reported in the clinical trial referred to, it is suggested that bismuth blood level values below 50 micrograms/ml are highly unlikely to be associated with meaningful toxicity in man. Finally, attention is drawn to the reversibility of bismuth toxicity in man as reported by many authors irrespective of the type of bismuth

  15. Pharmacokinetics and toxicity of bismuth compounds.

    PubMed

    Slikkerveer, A; de Wolff, F A

    1989-01-01

    Inorganic bismuth salts are poorly soluble in water: solubility is influenced by the acidity of the medium and the presence of certain compounds with (hydr)oxy or sulfhydryl groups. The analysis of bismuth in biological material is not standardised and is subject to large variation; it is difficult to compare data from different studies, and older data should be approached with caution. The normal concentration of bismuth in blood is between 1 and 15 micrograms/L, but absorption from oral preparations produces a significant rise. Distribution of bismuth in the organs is largely independent of the compound administered or the route of administration: the concentration in kidney is always highest and the substance is also retained there for a long time. It is bound to a bismuth-metal binding protein in the kidney, the synthesis of which can be induced by the metal itself. Elimination from the body takes place by the urinary and faecal routes, but the exact proportion contributed by each route is still unknown. Elimination from blood displays multicompartment pharmacokinetics, the shortest half-life described in humans being 3.5 minutes, and the longest 17 to 22 years. A number of toxic effects have been attributed to bismuth compounds in humans: nephropathy, encephalopathy, osteoarthropathy, gingivitis, stomatitis and colitis. Whether hepatitis is a side effect, however, is open to dispute. Each of these adverse effects is associated with certain bismuth compounds. Bismuth encephalopathy occurred in France as an epidemic of toxicity and was associated with the intake of inorganic salts including bismuth subnitrate, subcarbonate and subgallate. In the prodromal phase patients developed problems in walking, standing or writing, deterioration of memory, changes in behaviour, insomnia and muscle cramps, together with several psychiatric symptoms. The manifest phase started abruptly and was characterised by changes in awareness, myoclonia, astasia and/or abasia and

  16. Brain and blood levels of bismuth after oral or parenteral administration of tripotassium-dicitrato bismuthate to rats.

    PubMed

    Abbracchio, M P; Balduini, W; Cavallaro, A; Adamoli, P; Fittipaldi, M; Muzio, F; Malandrino, S; Cattabeni, F

    1985-01-01

    Bismuth levels in blood and brain of rats have been measured following acute or subchronic administration of tri-potassium-dicitrato bismuthate (TDB) by intraperitoneal injection or by gavage. After parenteral administration, the presence of bismuth in blood was associated with appreciable bismuth concentrations in brain of treated animals (approximately equal to 10-30% of blood levels). In contrast, following oral treatment, no bismuth was detected in brain of animals, even at doses of TDB able to produce blood bismuth concentrations comparable with those obtained after intraperitoneal administration. The formation of different bismuth species in blood of treated animals depending upon the route of administration of TDB is suggested.

  17. Ultrafast Bond Softening in Bismuth: Mapping a Solid’s Interatomic Potential with X-rays

    NASA Astrophysics Data System (ADS)

    Fritz, D. M.; Reis, D. A.; Adams, B.; Akre, R. A.; Arthur, J.; Blome, C.; Bucksbaum, P. H.; Cavalieri, A. L.; Engemann, S.; Fahy, S.; Falcone, R. W.; Fuoss, P. H.; Gaffney, K. J.; George, M. J.; Hajdu, J.; Hertlein, M. P.; Hillyard, P. B.; Horn-von Hoegen, M.; Kammler, M.; Kaspar, J.; Kienberger, R.; Krejcik, P.; Lee, S. H.; Lindenberg, A. M.; McFarland, B.; Meyer, D.; Montagne, T.; Murray, É. D.; Nelson, A. J.; Nicoul, M.; Pahl, R.; Rudati, J.; Schlarb, H.; Siddons, D. P.; Sokolowski-Tinten, K.; Tschentscher, Th.; von der Linde, D.; Hastings, J. B.

    2007-02-01

    Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.

  18. Ultrafast bond softening in bismuth: mapping a solid's interatomic potential with X-rays.

    PubMed

    Fritz, D M; Reis, D A; Adams, B; Akre, R A; Arthur, J; Blome, C; Bucksbaum, P H; Cavalieri, A L; Engemann, S; Fahy, S; Falcone, R W; Fuoss, P H; Gaffney, K J; George, M J; Hajdu, J; Hertlein, M P; Hillyard, P B; Horn-von Hoegen, M; Kammler, M; Kaspar, J; Kienberger, R; Krejcik, P; Lee, S H; Lindenberg, A M; McFarland, B; Meyer, D; Montagne, T; Murray, E D; Nelson, A J; Nicoul, M; Pahl, R; Rudati, J; Schlarb, H; Siddons, D P; Sokolowski-Tinten, K; Tschentscher, Th; von der Linde, D; Hastings, J B

    2007-02-02

    Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.

  19. Preparation of layered thin film samples for angle-resolved photoemission spectroscopy

    SciTech Connect

    Harrison, S. E.; Zhou, B.; Huo, Y.; Harris, J. S.; Pushp, A.; Kellock, A. J.; Parkin, S. S. P.; Chen, Y.; Hesjedal, T.

    2014-09-22

    Materials with layered van der Waals crystal structures are exciting research topics in condensed matter physics and materials science due to outstanding physical properties associated with their strong two dimensional nature. Prominent examples include bismuth tritelluride and triselenide topological insulators (TIs), which are characterized by a bulk bandgap and pairwise counter-propagating spin-polarized electronic surface states. Angle-resolved photoemission spectroscopy (ARPES) of ex-situ grown thin film samples has been limited by the lack of suitable surface preparation techniques. We demonstrate the shortcomings of previously successful conventional surface preparation techniques when applied to ternary TI systems which are susceptible to severe oxidation. We show that in-situ cleaving is a simple and effective technique for preparation of clean surfaces on ex-situ grown thin films for high quality ARPES measurements. The method presented here is universally applicable to other layered van der Waals systems as well.

  20. PROCESS OF COATING METALS WITH BISMUTH OR BISMUTH-BASE ALLOYS

    DOEpatents

    Beach, J.G.

    1958-01-28

    A method is described for producing coatings of bismuth or bismuth alloys on a metal base. This is accomplished by electrodepositing the bismuth from an aqueous solution of BiCl/sub 3/, and by making the metal base alternately the cathode and the anode, the cathode periods being twice as long as the anode periods. In one embodiment a nickel coating is first electrodeposited in a known way, and this nickel plated piece is tae base upon which tae bismuth is deposited by the process of this patent. The coated piece is then heat treated to produce a homogeneous Ni--Bi alloy by diffusion.

  1. Influence of RF excitation during pulsed laser deposition in oxygen atmosphere on the structural properties and luminescence of nanocrystalline ZnO:Al thin films

    SciTech Connect

    Meljanac, Daniel Plodinec, Milivoj; Siketić, Zdravko; Gracin, Davor; Juraić, Krunoslav; Bernstorff, Sigrid

    2016-03-15

    Thin ZnO:Al layers were deposited by pulsed laser deposition in vacuum and in oxygen atmosphere at gas pressures between 10 and 70 Pa and by applying radio-frequency (RF) plasma. Grazing incidence small angle x-ray scattering and grazing incidence x-ray diffraction (GIXRD) data showed that an increase in the oxygen pressure leads to an increase in the roughness, a decrease in the sample density, and changes in the size distribution of nanovoids. The nanocrystal sizes estimated from GIXRD were around 20 nm, while the sizes of the nanovoids increased from 1 to 2 nm with the oxygen pressure. The RF plasma mainly influenced the nanostructural properties and point defects dynamics. The photoluminescence consisted of three contributions, ultraviolet (UV), blue emission due to Zn vacancies, and red emission, which are related to an excess of oxygen. The RF excitation lowered the defect level related to blue emission and narrowed the UV luminescence peak, which indicates an improvement of the structural ordering. The observed influence of the deposition conditions on the film properties is discussed as a consequence of two main effects: the variation of the energy transfer from the laser plume to the growing film and changes in the growth chemistry.

  2. Sandwich heterostructures of antimony trioxide and bismuth trioxide films: Structural, morphological and optical analysis

    NASA Astrophysics Data System (ADS)

    Condurache-Bota, Simona; Praisler, Mirela; Gavrila, Raluca; Tigau, Nicolae

    2017-01-01

    Thin film heterostructures can be advantageous since they either exhibit novel or a combination of the properties of their components. Here we propose sandwich-type of heterostructures made of antimony trioxide and bismuth trioxide thin films, which were deposited on glass substrates by thermal vacuum deposition at three substrate temperatures, 50° Celsius apart. Their morphology and optical properties are studied as compared to the corresponding monolayers. It was found that even small substrate temperature changes strongly influence their morphology, increasing their roughness, while the optical transmittance shows a slight decrease as compared with the individual layers. The corresponding absorption coefficient exhibits intermediate values as compared to the component oxides, while the energy bandgaps for the indirect allowed transitions move towards the Infrared when overlapping the antimony and bismuth trioxides.

  3. Bismuth-based electrochemical stripping analysis

    DOEpatents

    Wang, Joseph

    2004-01-27

    Method and apparatus for trace metal detection and analysis using bismuth-coated electrodes and electrochemical stripping analysis. Both anodic stripping voltammetry and adsorptive stripping analysis may be employed.

  4. Effect of bismuth subsalicylate on ciprofloxacin bioavailability.

    PubMed Central

    Rambout, L; Sahai, J; Gallicano, K; Oliveras, L; Garber, G

    1994-01-01

    A single oral dose of 528 mg of bismuth subsalicylate (30 ml of Pepto-Bismol) had no significant effect on the plasma pharmacokinetics of a single oral dose of 750 mg of ciprofloxacin administered to 12 healthy volunteers (six men and six women). These results suggest that ciprofloxacin bioavailability will not be significantly decreased by single doses of bismuth subsalicylate when the two medications are administered simultaneously. PMID:7811043

  5. Evaluation of bismuth germanate detectors

    SciTech Connect

    Swinth, K.L.; Eschbach, P.A.

    1993-12-01

    During International Atomic Energy Agency (IAEA) safeguards inspections, one of the activities is the verification of materials in the inventory through quantitative or qualitative measurements. Performance of these measurements requires an array of sophisticated detectors, electronics, shields, and stands. This requires the transport and handling of delicate systems that are both heavy and bulky. The increasing sophistication and miniaturization of electronic and computer systems have led to progressive reductions in both the weight and the bulk of such electronics. However, to take full advantage of these improvements, similar reductions must also occur in the size and weight of the detectors. The purpose of this study was to explore the usefulness of one type of new detector, the bismuth germinate (BGO) scintillator. The purpose was to test detectors for their performance at high (fission products) and low ({sup 235}U) photon energies. Information is also provided on other scintillators, including those using photodiode-coupled cesium iodide and germanium orthosilicate.

  6. Thermoelectric Micro-Refrigerator Based on Bismuth/Antimony Telluride

    NASA Astrophysics Data System (ADS)

    Dang, Linh Tuan; Dang, Tung Huu; Nguyen, Thao Thi Thu; Nguyen, Thuat Tran; Nguyen, Hue Minh; Nguyen, Tuyen Viet; Nguyen, Hung Quoc

    2017-03-01

    Thermoelectric micro-coolers based on bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) are important in many practical applications thanks to their compactness and fluid-free circulation. In this paper, we studied thermoelectric properties of bismuth/antimony telluride (Bi/SbTe) thin films prepared by the thermal co-evaporation method, which yielded among the best thermoelectric quality. Different co-evaporation conditions such as deposition flux ratio of materials and substrate temperature during deposition were investigated to optimize the thermoelectric figure␣of merit of these materials. Micron-size refrigerators were designed and fabricated using standard lithography and etching technique. A three-layer structure was introduced, including a p-type layer, an n-type layer and an aluminum layer. Next to the main cooler, a pair of smaller Bi/SbTe junctions was used as a thermocouple to directly measure electron temperature of the main device. Etching properties of the thermoelectric materials were investigated and optimized to support the fabrication process of the micro-refrigerator. We discuss our results and address possible applications.

  7. Gravimetric Analysis of Bismuth in Bismuth Subsalicylate Tablets: A Versatile Quantitative Experiment for Undergraduate Laboratories

    ERIC Educational Resources Information Center

    Davis, Eric; Cheung, Ken; Pauls, Steve; Dick, Jonathan; Roth, Elijah; Zalewski, Nicole; Veldhuizen, Christopher; Coeler, Joel

    2015-01-01

    In this laboratory experiment, lower- and upper-division students dissolved bismuth subsalicylate tablets in acid and precipitated the resultant Bi[superscript 3+] in solution with sodium phosphate for a gravimetric determination of bismuth subsalicylate in the tablets. With a labeled concentration of 262 mg/tablet, the combined data from three…

  8. Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode.

    PubMed

    Lee, Gyoung-Ja; Kim, Chang Kyu; Lee, Min Ku; Rhee, Chang Kyu

    2010-12-15

    Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode has been investigated using square-wave anodic stripping voltammetry technique, scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectroscopy. From the analyses of square-wave anodic stripping voltammograms (SWASV) repetitively measured on the nano-bismuth fixed electrode, it was found that the oxidation peak currents dropped by 81%, 68% and 59% for zinc, cadmium and lead, respectively, after the 100th measurement (about 400 min of operation time). The sphere bismuth nanoparticles gradually changed to the agglomerates with petal shape as the operation time increased. From the analyses of SEM images and XRD patterns, it is confirmed that the oxidation of Bi into BiOCl/Bi(2)O(2)CO(3) and the agglomeration of bismuth nanoparticles caused by the phase change decrease a reproducibility of the stripping voltammetric response. Moreover, most of the bismuth becomes BiOCl at pH 3.0 and bismuth hydroxide, Bi(OH)(3) at pH 7.0, which results in a significant decrease in sensitivity of the nano-bismuth fixed electrode.

  9. Thermal degradation of ultrabroad bismuth NIR luminescence in bismuth-doped tantalum germanate laser glasses.

    PubMed

    Wang, Liping; Zhao, Yanqi; Xu, Shanhui; Peng, Mingying

    2016-04-01

    Because of ultra-broadband luminescence in 1000-1700 nm and consequent applications in fiber amplifier and lasers in the new spectral range where traditional rare earth cannot work, bismuth-doped laser glasses have received rising interest recently. For long-term practical application, thermal degradation must be considered for the glasses. This, however, has seldom been investigated. Here we report the thermal degradation of bismuth-doped germanate glass. Heating and cooling cycle experiments at high temperature reveal strong dependence of the thermal degradation on glass compositions. Bismuth and tantalum lead to the reversible degradation, while lithium can produce permanent irreversible degradation. The degradation becomes worse as lithium content increases in the glass. Absorption spectra show this is due to partial oxidation of bismuth near-infrared emission center. Surprisingly, we notice the emission of bismuth exhibits blueshift, rather than redshift at a higher temperature, and the blueshift can be suppressed by increasing the lithium content.

  10. Luminescence properties of IR-emitting bismuth centres in SiO{sub 2}-based glasses in the UV to near-IR spectral region

    SciTech Connect

    Firstova, E G; Vel'miskin, V V; Firstov, S V; Dianov, E M; Bufetov, I A; Khopin, V F; Gur'yanov, A N; Bufetova, G A; Nishchev, K N

    2015-01-31

    We have studied UV excitation spectra of IR luminescence in bismuth-doped glasses of various compositions and obtained energy level diagrams of IR-emitting bismuth-related active centres (BACs) associated with silicon and germanium atoms up to ∼5.2 eV over the ground level. A possible energy level diagram of the BACs in phosphosilicate glass has been proposed. The UV excitation peaks for the IR luminescence of the BACs in the glasses have been shown to considerably overlap with absorption bands of the Bi{sup 3+} ion, suggesting that Bi{sup 3+} may participate in BAC formation. (optical fibres)

  11. Luminescence properties of IR-emitting bismuth centres in SiO2-based glasses in the UV to near-IR spectral region

    NASA Astrophysics Data System (ADS)

    Firstova, E. G.; Bufetov, I. A.; Khopin, V. F.; Vel'miskin, V. V.; Firstov, S. V.; Bufetova, G. A.; Nishchev, K. N.; Gur'yanov, A. N.; Dianov, E. M.

    2015-01-01

    We have studied UV excitation spectra of IR luminescence in bismuth-doped glasses of various compositions and obtained energy level diagrams of IR-emitting bismuth-related active centres (BACs) associated with silicon and germanium atoms up to ~5.2 eV over the ground level. A possible energy level diagram of the BACs in phosphosilicate glass has been proposed. The UV excitation peaks for the IR luminescence of the BACs in the glasses have been shown to considerably overlap with absorption bands of the Bi3+ ion, suggesting that Bi3+ may participate in BAC formation.

  12. Bismuth alloy potting seals aluminum connector in cryogenic application

    NASA Technical Reports Server (NTRS)

    Flower, J. F.; Stafford, R. L.

    1966-01-01

    Bismuth alloy potting seals feedthrough electrical connector for instrumentation within a pressurized vessel filled with cryogenic liquids. The seal combines the transformation of high-bismuth content alloys with the thermal contraction of an external aluminum tube.

  13. Liquid Bismuth Propellant Flow Sensor

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Stanojev, B. J.; Korman, V.

    2007-01-01

    Quantifying the propellant mass flow rate in liquid bismuth-fed electric propulsion systems has two challenging facets. First, the flow sensors must be capable of providing a resolvable measurement at propellant mass flow rates on the order of 10 mg/see with and uncertainty of less that 5%. The second challenge has to do with the fact that the materials from which the flow sensors are fabricated must be capable of resisting any of the corrosive effects associated with the high-temperature propellant. The measurement itself is necessary in order to properly assess the performance (thrust efficiency, Isp) of thruster systems in the laboratory environment. The hotspot sensor[I] has been designed to provide the bismuth propellant mass flow rate measurement. In the hotspot sensor, a pulse of thermal energy (derived from a current pulse and associated joule heating) is applied near the inlet of the sensor. The flow is "tagged" with a thermal feature that is convected downstream by the flowing liquid metal. Downstream, a temperature measurement is performed to detect a "ripple" in the local temperature associated with the passing "hotspot" in the propellant. By measuring the time between the upstream generation and downstream detection of the thermal feature, the flow speed can be calculated using a "time of flight" analysis. In addition, the system can be calibrated by measuring the accumulated mass exiting the system as a-function of time and correlating this with the time it takes the hotspot to convect through the sensor. The primary advantage of this technique is that it doesn't depend on an absolute measurement of temperature but, instead, relies on the observation of thermal features. This makes the technique insensitive to other externally generated thermal fluctuations. In this paper, we describe experiments performed using the hotspot flow sensor aimed at quantifying the resolution of the sensor technology. Propellant is expelled onto an electronic scale to

  14. Dynamics of lithium ions in bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Pan, A.; Ghosh, A.

    2000-01-01

    The dynamics of lithium ions in lithium bismuthate glasses have been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 323 to 543 K. The composition dependence of the dc (direct current) conductivity has been explained in terms of the structure of bismuthate glasses. The activation energy has been analyzed in the framework of the Anderson-Stuart model. An additional energy term arising from the Madelung constant of glasses and the polarizability of the bismuth ions has been suggested to explain the discrepancy between the calculated and experimentally obtained values. The relaxation mechanism of these glasses has been explored by employing the modulus and conductivity formalisms and the microscopic parameters obtained from the analysis have been compared. Furthermore, the stretched exponential relaxation parameter and the dc conductivity have been correlated with the decoupling index.

  15. Liquid Bismuth Feed System for Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Markusic, T. E.; Polzin, K. A.; Stanojev, B. J.

    2006-01-01

    Operation of Hall thrusters with bismuth propellant has been shown to be a promising path toward high-power, high-performance, long-lifetime electric propulsion for spaceflight missions. For example, the VHITAL project aims td accurately, experimentally assess the performance characteristics of 10 kW-class bismuth-fed Hall thrusters - in order to validate earlier results and resuscitate a promising technology that has been relatively dormant for about two decades. A critical element of these tests will be the precise metering of propellant to the thruster, since performance cannot be accurately assessed without an accurate accounting of mass flow rate. Earlier work used a pre/post-test propellant weighing scheme that did not provide any real-time measurement of mass flow rate while the thruster was firing, and makes subsequent performance calculations difficult. The motivation of the present work was to develop a precision liquid bismuth Propellant Management System (PMS) that provides real-time propellant mass flow rate measurement and control, enabling accurate thruster performance measurements. Additionally, our approach emphasizes the development of new liquid metal flow control components and, hence, will establish a basis for the future development of components for application in spaceflight. The design of various critical components in a bismuth PMS are described - reservoir, electromagnetic pump, hotspot flow sensor, and automated control system. Particular emphasis is given to material selection and high-temperature sealing techniques. Open loop calibration test results are reported, which validate the systems capability to deliver bismuth at mass flow rates ranging from 10 to 100 mg/sec with an uncertainty of less than +/- 5%. Results of integrated vaporizer/liquid PMS tests demonstrate all of the necessary elements of a complete bismuth feed system for electric propulsion.

  16. Absorption and elimination of bismuth from oral doses of tripotassium dicitrato bismuthate.

    PubMed

    Froomes, P R; Wan, A T; Keech, A C; McNeil, J J; McLean, A J

    1989-01-01

    The pharmacokinetics of bismuth subcitrate were studied in plasma and urine under conditions of single and multiple dosing (28-56 days) using atomic absorption technique. Single dose plasma pharmacokinetics showed peak concentrations of 5.5-57.5 micrograms.l-1 (mean = 24.7 micrograms.l-1), reached between 30 and 60 min post dosing with an apparent biphasic elimination pattern. Multiple dose studies showed a continuing rise in plasma concentration and urine excretion rate reaching apparent steady-state levels over 7-29 days (mean = 18 days). Washout studies in 6 individuals reciprocated accumulation. Maximum equilibrated plasma levels of 7.6-58.3 micrograms.l-1 (mean = 38.3 micrograms.l-1) were well below those associated with encephalopathy. The half-life of bismuth elimination was 20.7 days. Present patterns of intermittent dosing with bismuth are unlikely to be associated with bismuth accumulation despite slow accumulation and elimination.

  17. Dielectric and Optical Properties of Thin Films.

    DTIC Science & Technology

    1978-08-01

    Is const ructed from a thin slice of bismuth silicon oxlde,~ a cubic crystal exhibiting the Pockels effect. The crystal also is photoconductive when... Photoconductive diameter electro -optical crystal ~~~~~~~~~~~~~~~~~ i12SiO20) Electrode 2 Insulator layer Electrode 1 (paralene) Figure 1-1

  18. Probing bismuth ferrite nanoparticles by hard x-ray photoemission: Anomalous occurrence of metallic bismuth

    SciTech Connect

    Chaturvedi, Smita; Rajendra, Ranguwar; Ballav, Nirmalya; Kulkarni, Sulabha; Sarkar, Indranil; Shirolkar, Mandar M.; Jeng, U-Ser; Yeh, Yi-Qi

    2014-09-08

    We have investigated bismuth ferrite nanoparticles (∼75 nm and ∼155 nm) synthesized by a chemical method, using soft X-ray (1253.6 eV) and hard X-ray (3500, 5500, and 7500 eV) photoelectron spectroscopy. This provided an evidence for the variation of chemical state of bismuth in crystalline, phase pure nanoparticles. X-ray photoelectron spectroscopy analysis using Mg Kα (1253.6 eV) source showed that iron and bismuth were present in both Fe{sup 3+} and Bi{sup 3+} valence states as expected for bismuth ferrite. However, hard X-ray photoelectron spectroscopy analysis of the bismuth ferrite nanoparticles using variable photon energies unexpectedly showed the presence of Bi{sup 0} valence state below the surface region, indicating that bismuth ferrite nanoparticles are chemically inhomogeneous in the radial direction. Consistently, small-angle X-ray scattering reveals a core-shell structure for these radial inhomogeneous nanoparticles.

  19. Bismuth induced encephalopathy caused by tri potassium dicitrato bismuthate in a patient with chronic renal failure.

    PubMed

    Playford, R J; Matthews, C H; Campbell, M J; Delves, H T; Hla, K K; Hodgson, H J; Calam, J

    1990-03-01

    A 68 year old man with a creatinine clearance rate of only 15 ml/min took twice the recommended dose of tripotassium dicitrato bismuthate (TDB) as DeNol liquid; 10 ml qds; a total of 864 mg bismuth daily for two months. Whole blood bismuth concentrations rose to 880 micrograms/l and he developed global cerebral dysfunction with hallucinations, ataxia, and an abnormal EEG. Renal clearance of bismuth rose from 0.24 to 2.4 ml/min when the heavy metal chelator 2-3 dimercapto-1 propane sulphonic acid (DMPS) was given by mouth. Bismuth was measured by a novel method involving inductively coupled plasma source mass spectrometry. Fifty days after stopping TDB, whole blood bismuth concentrations fell to 46 micrograms/l and the patient's EEG returned to normal. His mental function also recovered completely. The case serves as a timely reminder that TDB should not be administered to patients with renal disorders, as stated in the data sheet.

  20. Bismuth induced encephalopathy caused by tri potassium dicitrato bismuthate in a patient with chronic renal failure.

    PubMed Central

    Playford, R J; Matthews, C H; Campbell, M J; Delves, H T; Hla, K K; Hodgson, H J; Calam, J

    1990-01-01

    A 68 year old man with a creatinine clearance rate of only 15 ml/min took twice the recommended dose of tripotassium dicitrato bismuthate (TDB) as DeNol liquid; 10 ml qds; a total of 864 mg bismuth daily for two months. Whole blood bismuth concentrations rose to 880 micrograms/l and he developed global cerebral dysfunction with hallucinations, ataxia, and an abnormal EEG. Renal clearance of bismuth rose from 0.24 to 2.4 ml/min when the heavy metal chelator 2-3 dimercapto-1 propane sulphonic acid (DMPS) was given by mouth. Bismuth was measured by a novel method involving inductively coupled plasma source mass spectrometry. Fifty days after stopping TDB, whole blood bismuth concentrations fell to 46 micrograms/l and the patient's EEG returned to normal. His mental function also recovered completely. The case serves as a timely reminder that TDB should not be administered to patients with renal disorders, as stated in the data sheet. PMID:2323603

  1. 21 CFR 73.2110 - Bismuth citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... restrictions. The color additive bismuth citrate may be safely used in cosmetics intended for coloring hair on..., eyebrows, or hair on parts of the body other than the scalp. (d) Labeling. (1) The label of the color... abraded scalp. Do not use to color eyelashes, eyebrows, or hair on parts of the body other than the...

  2. 21 CFR 73.2110 - Bismuth citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... restrictions. The color additive bismuth citrate may be safely used in cosmetics intended for coloring hair on..., eyebrows, or hair on parts of the body other than the scalp. (d) Labeling. (1) The label of the color... abraded scalp. Do not use to color eyelashes, eyebrows, or hair on parts of the body other than the...

  3. 21 CFR 73.2110 - Bismuth citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... restrictions. The color additive bismuth citrate may be safely used in cosmetics intended for coloring hair on..., eyebrows, or hair on parts of the body other than the scalp. (d) Labeling. (1) The label of the color... abraded scalp. Do not use to color eyelashes, eyebrows, or hair on parts of the body other than the...

  4. 21 CFR 73.2110 - Bismuth citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... restrictions. The color additive bismuth citrate may be safely used in cosmetics intended for coloring hair on..., eyebrows, or hair on parts of the body other than the scalp. (d) Labeling. (1) The label of the color... abraded scalp. Do not use to color eyelashes, eyebrows, or hair on parts of the body other than the...

  5. 21 CFR 73.2110 - Bismuth citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... restrictions. The color additive bismuth citrate may be safely used in cosmetics intended for coloring hair on..., eyebrows, or hair on parts of the body other than the scalp. (d) Labeling. (1) The label of the color... abraded scalp. Do not use to color eyelashes, eyebrows, or hair on parts of the body other than the...

  6. 21 CFR 73.2162 - Bismuth oxychloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2162 Bismuth oxychloride. (a) Identity and... following diluents: (i) For coloring cosmetics generally, only those diluents listed under § 73.1001(a)(1); (ii) For coloring externally applied cosmetics, only those diluents listed in § 73.1001(b) and,...

  7. 21 CFR 73.2162 - Bismuth oxychloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2162 Bismuth oxychloride. (a) Identity and... following diluents: (i) For coloring cosmetics generally, only those diluents listed under § 73.1001(a)(1); (ii) For coloring externally applied cosmetics, only those diluents listed in § 73.1001(b) and,...

  8. 21 CFR 73.2162 - Bismuth oxychloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2162 Bismuth oxychloride. (a) Identity and... following diluents: (i) For coloring cosmetics generally, only those diluents listed under § 73.1001(a)(1); (ii) For coloring externally applied cosmetics, only those diluents listed in § 73.1001(b) and,...

  9. 21 CFR 73.2162 - Bismuth oxychloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2162 Bismuth oxychloride. (a) Identity and... following diluents: (i) For coloring cosmetics generally, only those diluents listed under § 73.1001(a)(1); (ii) For coloring externally applied cosmetics, only those diluents listed in § 73.1001(b) and,...

  10. Development and Investigation of Bismuth Nanowires

    DTIC Science & Technology

    2008-06-05

    To: technicalreports@afosr.af.mil Subject: Final Statement to Dr. Donald Silversmith Contract/Grant Title: Development and Investigation of...Report Development and Investigation of Bismuth Nanowires – Start up phase FA9550-07-1-0472 To Dr. Donald Silversmith AFOSR PI: Jimmy Xu

  11. Hydrothermal synthesis map of bismuth titanates

    SciTech Connect

    Sardar, Kripasindhu; Walton, Richard I.

    2012-05-15

    The hydrothermal synthesis of four bismuth titanate materials from common bismuth and titanium precursors under hydrothermal conditions is described. Reaction of NaBiO{sub 3}{center_dot}2H{sub 2}O and anatase TiO{sub 2} in concentrated NaOH solution at 240 Degree-Sign C is shown to produce perovskite and sillenite phases Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} and Bi{sub 12}TiO{sub 20}, depending on the ratio of metal precursors used. When KOH solution is used and a 1:1 ratio of the same precursors, a pyrochlore Bi{sub 1.43}Ti{sub 2}O{sub 6}(OH){sub 0.29}(H{sub 2}O){sub 0.66} is formed. The use of a mixture of HNO{sub 3} and NaOH is shown to facilitate the formation of the Aurivillius-type bismuth titanate Bi{sub 4}Ti{sub 3}O{sub 12}. The phases have been isolated separately as phase-pure powders and profile refinement of powder X-ray diffraction data allows comparisons with comparable materials reported in the literature. Analysis of Bi L{sub III}-edge X-ray absorption near edge structure (XANES) spectra of the materials shows the oxidation state of bismuth is +3 in all of the hydrothermally derived products. - Graphical abstract: Use of NaBiO{sub 3}{center_dot}2H{sub 2}O and TiO{sub 2} as reagents under hydrothermal conditions allows the phase-pure preparation of four crystalline bismuth titanate materials. Highlights: Black-Right-Pointing-Pointer NaBiO{sub 3} and TiO{sub 2} under hydrothermal conditions allow formation of bismuth titanates. Black-Right-Pointing-Pointer Synthesis of four distint phases has been mapped. Black-Right-Pointing-Pointer Bi LIII-edge XANES shows Bi is reduced to oxidation state +3 in all materials. Black-Right-Pointing-Pointer A new hydrated bismuth titanate pyrochlore has been isolated.

  12. Ferroelectric properties of niobium-doped strontium bismuth tantalate films

    NASA Astrophysics Data System (ADS)

    Golosov, D. A.; Zavadski, S. M.; Kolos, V. V.; Turtsevich, A. S.

    2016-01-01

    The characteristics of ferroelectric thin films of strontium bismuth tantalate (SBT) and niobium-doped strontium bismuth tantalate (SBTN) deposited by radio-frequency (RF) magnetron sputtering on Pt/TiO2/SiO2/Si substrates were investigated. For the formation of the structure of the ferroelectric material, the deposited films were subjected to a subsequent annealing at temperatures of 970-1070 K in an O2 atmosphere. The results of the X-ray diffraction analysis demonstrated that, in contrast to SBT films, in which the Aurivillius phase is formed only at annealing temperatures of 1050-1070 K, the formation of this phase in SBTN films is observed already at a temperature of 970 K. The dependences of the dielectric permittivity, remanent polarization, and coercive force of the SBT and SBTN films on the subsequent annealing conditions were determined. It was found that, upon doping of the SBT films with niobium, the remanent polarization increases by a factor of approximately three, the Curie temperature increases by 50 K, and the dielectric permittivity also increases. It was revealed that, in contrast to the SBT films, the polarization of the SBTN films is observed already at an annealing temperature of approximately 970 K. It was shown that the replacement of SBT films by SBTN films in the manufacture of high-density nonvolatile ferroelectric randomaccess memory (FeRAM) capacitor modules makes it possible to decrease the synthesis temperature from 1070 to 990-1000 K, which improves the compatibility with the planar technology of semiconductor devices. However, it turned out that an increase in the coercive field makes niobium-doped SBT films less attractive for the use in FeRAM.

  13. Autometallographic tracing of bismuth in human brain autopsies.

    PubMed

    Stoltenberg, M; Hogenhuis, J A; Hauw, J J; Danscher, G

    2001-07-01

    For decades, drugs containing bismuth have been used to treat gastrointestinal disorders. Although a variety of adverse effects, including neurological syndromes, have been recorded, the biological/toxicological effects of bismuth ions are far from disclosed. Until recently, only quantitative assessments were possible, but resent research has made histochemical tracing of bismuth possible. The technique involves silver enhancement of bismuth crystallites by autometallography (AMG). In the present study, the localization of bismuth was traced by AMG in sections of paraffin-embedded brain tissue obtained by autopsy from 6 patients suffering from bismuth intoxication in a period ranging from 1975 through 1977. Tissue was analyzed at light and electron microscopical levels, and the presence of bismuth further confirmed by proton-induced x-ray emission (PIXE). Clinical data and bismuth concentrations in blood, cerebellum, and thalamus were measured by atomic absorption spectrophotometry (AAS) and are reported here. Histochemical analyses demonstrate that bismuth accumulated in neurons and glia cells in the brain regions examined (neocortex, cerebellum, thalamus, hippocampus). Cerebellar blood vessels stained most intensely. The PIXE and AAS data correlated with the histochemical staining patterns and intensities. At the ultrastructural level, bismuth was found to accumulate intracellularly in lysosomes and extracellularly in the basement membranes of some vessels.

  14. Intense 2.7 µm emission and structural origin in Er3+-doped bismuthate (Bi2O3-GeO2-Ga2O3-Na2O) glass.

    PubMed

    Guo, Yanyan; Li, Ming; Hu, Lili; Zhang, Junjie

    2012-01-15

    The 2.7 μm emission properties in Er3+-doped bismuthate (Bi2O3-GeO2-Ga2O3-Na2O) glass were investigated in the present Letter. An intense 2.7 μm emission in Er3+-doped bismuthate glass was observed. It is found that Er3+-doped bismuthate glass possesses high spontaneous transition probability A (65.26 s(-1)) and large 2.7 μm emission cross section σ(em) (9.53×10(-21) cm2) corresponding to the stimulated emission of Er3+:4I11/2→4I13/2 transition. The emission characteristic and energy transfer process upon excitation of a conventional 980 nm laser diode in bismuthate glass were analyzed. Additionally, the structure of bismuthate glass was analyzed by the Raman spectrum. The advantageous spectroscopic characteristics of Er3+ single-doped bismuthate glass together with the prominent thermal property indicate that bismuthate glass might become an attractive host for developing solid-state lasers around 2.7 μm.

  15. Syntheses, crystal structures and characterizations of two new bismuth(III) arsenites

    SciTech Connect

    Liu Junhui; Kong Fang; Gai Yanli; Mao Jianggao

    2013-01-15

    Two new bismuth arsenites with two different structural types, namely, Bi{sub 2}O(AsO{sub 3})Cl (1), Bi{sub 8}O{sub 6}(AsO{sub 3}){sub 2}(AsO{sub 4}){sub 2} (2), have been synthesized by the solid-state reactions. Compound 1 exhibits novel 2D bismuth arsenite layers with Bi{sub 4}O{sub 4} rings capped by oxide anions, which are further interconnected by Bi-Cl-Bi bridges into a 3D network. Compound 2 contains both arsenite and arsenate anions, its 3D structures are based on 1D bismuth arsenite and 1D bismuth arsenate chains both along b-axis, which are interconnected by oxide anions via Bi-O-Bi bridges, forming 1D tunnels of Bi{sub 4}As{sub 4} 8-membered rings (MRs) along b-axis, the lone pairs of the arsenite groups are orientated toward the centers of the above tunnels. Thermogravimetric analysis indicated that both compounds display high thermal stability. Optical property measurements revealed that they are wide band-gap semiconductors. Both compounds display broad green-light emission bands centered at 506 nm under excitation at 380 and 388 nm. - Graphical abstract: Solid state reactions of Bi{sub 2}O{sub 3} (BiCl{sub 3}) and As{sub 2}O{sub 3} yielded two new compounds with two different structural types, namely, Bi{sub 2}O(AsO{sub 3})Cl (1), Bi{sub 8}O{sub 6}(AsO{sub 3}){sub 2}(AsO{sub 4}){sub 2} (2). They represent the first examples of bismuth arsenates. Highlights: Black-Right-Pointing-Pointer Solid state reactions of Bi{sub 2}O{sub 3} (BiCl{sub 3}) and As{sub 2}O{sub 3} yielded two new phases. Black-Right-Pointing-Pointer They represent the first examples of bismuth arsenites. Black-Right-Pointing-Pointer The two compounds exhibit two different structural types.

  16. Optical pumping and readout of bismuth hyperfine states in silicon for atomic clock applications

    PubMed Central

    Saeedi, K.; Szech, M.; Dluhy, P.; Salvail, J.Z.; Morse, K.J.; Riemann, H.; Abrosimov, N.V.; Nötzel, N.; Litvinenko, K.L.; Murdin, B.N.; Thewalt, M.L.W.

    2015-01-01

    The push for a semiconductor-based quantum information technology has renewed interest in the spin states and optical transitions of shallow donors in silicon, including the donor bound exciton transitions in the near-infrared and the Rydberg, or hydrogenic, transitions in the mid-infrared. The deepest group V donor in silicon, bismuth, has a large zero-field ground state hyperfine splitting, comparable to that of rubidium, upon which the now-ubiquitous rubidium atomic clock time standard is based. Here we show that the ground state hyperfine populations of bismuth can be read out using the mid-infrared Rydberg transitions, analogous to the optical readout of the rubidium ground state populations upon which rubidium clock technology is based. We further use these transitions to demonstrate strong population pumping by resonant excitation of the bound exciton transitions, suggesting several possible approaches to a solid-state atomic clock using bismuth in silicon, or eventually in enriched 28Si. PMID:25990870

  17. Exfoliation and characterization of bismuth telluride atomic quintuples and quasi-two-dimensional crystals.

    PubMed

    Teweldebrhan, Desalegne; Goyal, Vivek; Balandin, Alexander A

    2010-04-14

    Bismuth telluride (Bi(2)Te(3)) and its alloys are the best bulk thermoelectric materials known today. In addition, stacked quasi-two-dimensional (2D) layers of Bi(2)Te(3) were recently identified as promising topological insulators. In this Letter we describe a method for "graphene-inspired" exfoliation of crystalline bismuth telluride films with a thickness of a few atoms. The atomically thin films were suspended across trenches in Si/SiO(2) substrates, and subjected to detail material characterization, which included atomic force microscopy and micro-Raman spectroscopy. The presence of the van der Waals gaps allowed us to disassemble Bi(2)Te(3) crystal into its quintuple building blocks-five monatomic sheets-consisting of Te((1))-Bi-Te((2))-Bi-Te((1)). By altering the thickness and sequence of atomic planes, we were able to create "designer" nonstoichiometric quasi-2D crystalline films, change their composition and doping, the type of charge carriers as well as other properties. The exfoliated quintuples and ultrathin films have low thermal conductivity, high electrical conductivity, and enhanced thermoelectric properties. The obtained results pave the way for producing stacks of crystalline bismuth telluride quantum wells with the strong spatial confinement of charge carriers and acoustic phonons, beneficial for thermoelectric devices. The developed technology for producing free-standing quasi-2D layers of Te((1))-Bi-Te((2))-Bi-Te((1)) creates an impetus for investigation of the topological insulators and their possible practical applications.

  18. Efficient gas sensitivity in mixed bismuth ferrite micro (cubes) and nano (plates) structures

    SciTech Connect

    Waghmare, Shivaji D.; Jadhav, Vijaykumar V.; Gore, Shaym K.; Yoon, Seog-Joon; Ambade, Swapnil B.; Lokhande, B.J.; Mane, Rajaram S.; Han, Sung-Hwan

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Micro (cubes) structure embedded in nano (plates) of bismuth ferrite was prepared by a chemical method. ► These structures were characterized by XRD and SEM. ► LPG, CO{sub 2} and NH{sub 4} gases were exposed. ► Properties related to gas sensors were measured and reported. -- Abstract: Mixed micro (cubes) and nano (plates) structures of bismuth ferrite (BFO) have been synthesized by a simple and cost-effective wet-chemical method. Structural, morphological and phase confirmation characteristics are measured using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis techniques. The digital FE-SEM photo-images of BFO sample confirmed an incubation of discrete micro-cubes into thin and regularly placed large number of nano-plates. The bismuth ferrite, with mixed structures, films show considerable performance when used in liquefied petroleum (LPG), carbon dioxide (CO{sub 2}) and ammonium (NH{sub 3}) gas sensors application. Different chemical entities in LPG have made it more efficient with higher sensitivity, recovery and response times compared to CO{sub 2} and NH{sub 3} gases. Furthermore, effect of palladium surface treatment on the gas sensitivity and the charge transfer resistances of BFO mixed structures is investigated and reported.

  19. The effect of tripotassium dicitrato bismuthate on pepsin activity.

    PubMed

    De Beaux, A C; Defize, J; Hunt, R H

    1989-08-01

    We have studied the effect of tripotassium dicitrato bismuthate on the peptic activity of gastric juice, both basal and pentagastrin-stimulated, from five healthy volunteers using porcine pepsin solution as a control. Tripotassium dicitrato bismuthate showed no inhibition of the proteolytic activity of either the pure porcine or the human pepsin in the gastric juice. The ulcer healing efficacy of tripotassium dicitrato bismuthate is unlikely to be related to a gastric anti-protease effect.

  20. Environmentally friendly organic synthesis using bismuth(III) compounds.

    PubMed

    Krabbe, Scott W; Mohan, Ram S

    2012-01-01

    With increasing environmental concerns, the need for environmentally friendly organic synthesis has gained increased importance. In this regard, bismuth(III) compounds are especially attractive as "green" reagents and catalysts for organic synthesis. Bismuth(III) compounds are remarkably nontoxic, relatively air and moisture stable, and easy to handle. The contributions from our laboratory in the last 5 years in the field of applications of bismuth(III) compounds as catalysts are presented.

  1. Comparative pharmacokinetics of bismuth from ranitidine bismuth citrate (GR122311X), a novel anti-ulcerant and tripotassium dicitrato bismuthate (TDB).

    PubMed

    Lacey, L F; Frazer, N M; Keene, O N; Smith, J T

    1994-01-01

    GR122311X (ranitidine bismuth citrate, Glaxo Group Research Ltd.) is a salt of ranitidine with a complex of bismuth and citric acid which is being developed for the treatment of peptic ulceration. In this study, 4 groups of 12 healthy male subjects were dosed for 10 days with either GR122311X 500 mg bid (301 mg bismuth per day), GR122311X 1.0 g bid (602 mg bismuth per day), tripotassium dicitrato bismuthate (TDB, DeNoltab, Gist Brocades Ltd., Weybridge, England) 240 mg bid (431 mg bismuth per day) or placebo. After the last dose the geometric mean for Cmax for 500 mg bid of GR122311X was 5 ng.g-1, for 1.0 g bid GR122311X it was 12 ng.g-1 and it was 21 ng.g-1 for 240 mg TDB bid. The corresponding trough plasma levels were 2 ng.g-1, 4 ng.g-1 and 4 ng.g-1, respectively. The AUC over a dosing interval after the last dose (AUC tau) were 34 ng.h.g-1, 71 ng.h.g-1 and 79 ng.h.g-1, respectively. The bismuth urinary recoveries over the last dosing interval (Ae tau) were 97 micrograms, 227 micrograms and 309 micrograms, respectively, which is less than 1% of the administered doses. The renal clearance of bismuth was less than the glomerular filtration rate. After adjustment for bismuth dose, the Cmax for GR122311X 500 mg was 35% that of TDB, while for GR122311X 1.0 g the Cmax was 42% that of TDB. Similar differences were observed for Ae tau. In conclusion bismuth pharmacokinetics after oral administration of GR1223311X exhibited lower Ae tau and Cmax, with a much narrower Cmax range than those observed for TDB.

  2. NEGATIVE PION PHOTOPRODUCTION FROM BISMUTH ACCOMPANIED BY NEUTRON EMISSION,

    DTIC Science & Technology

    BISMUTH, PIONS, EMISSIVITY, BREMSSTRAHLUNG, NUCLEI, ALPHA PARTICLE DETECTORS, PROTON REACTIONS, RADIOACTIVITY, PHOTONUCLEAR REACTIONS, POLONIUM , NUCLEAR STRUCTURE, MATHEMATICAL MODELS, PROBABILITY, SURFACES, DISTRIBUTION.

  3. Dielectric investigations of polycrystalline samarium bismuth ferrite ceramic

    NASA Astrophysics Data System (ADS)

    Palaimiene, E.; Macutkevic, J.; Karpinsky, D. V.; Kholkin, A. L.; Banys, J.

    2015-01-01

    Results of broadband dielectric investigations of samarium doped bismuth ferrite ceramics are presented in wide temperature range (20-800 K). At temperatures higher than 400 K, the dielectric properties of samarium bismuth ferrite ceramics are governed by Maxwell-Wagner relaxation and electrical conductivity. The DC conductivity increases and activation energy decreases with samarium concentration. In samarium doped bismuth ferrite, the ferroelectric phase transition temperature decreases with samarium concentration and finally no ferroelectric order is observed at x = 0.2. At lower temperatures, the dielectric properties of ferroelectric samarium doped bismuth ferrite are governed by ferroelectric domains dynamics. Ceramics with x = 0.2 exhibit the relaxor-like behaviour.

  4. Growth of epitaxial bismuth and gallium substituted lutetium iron garnet films by pulsed laser deposition

    SciTech Connect

    Leitenmeier, Stephan; Heinrich, Andreas; Lindner, Joerg K. N.; Stritzker, Bernd

    2006-04-15

    Epitaxial bismuth and gallium substituted lutetium iron garnet thin films have been grown on (100) oriented gadolinium gallium garnet Gd{sub 3}Ga{sub 5}O{sub 12} substrates by pulsed laser deposition. The films have been studied using x-ray diffraction, high resolution x-ray diffraction, Rutherford backscattering spectroscopy, transmission electron microscopy, and electron diffraction. We obtained smooth films with thicknesses between 0.3 and 1.0 {mu}m showing good crystalline quality and epitaxial growth.

  5. Li+ ion dynamics in strontium bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Dutta, A.; Ghosh, A.

    2004-11-01

    Ion transport in Li2O-Bi2O3-SrO glasses has been studied in the frequency range 10 Hz-2 MHz and in the temperature range 263-483 K. The variation of the dc conductivity and the activation energy of these glasses with composition has been compared with those of bismuthate and lead bismuthate glasses. The frequency dependent conductivity has been studied using both modulus and conductivity formalisms. We have observed that the variation of the power law exponent with Li2O content is in contrast to that for the Li2O-Bi2O3 and Li2O-Bi2O3-PbO glasses. The values of the non-exponential parameter for the Li2O-Bi2O3-SrO glasses are lower than those for the binary Li2O-Bi2O3 glasses.

  6. Structures of small bismuth cluster cations

    NASA Astrophysics Data System (ADS)

    Kelting, Rebecca; Baldes, Alexander; Schwarz, Ulrike; Rapps, Thomas; Schooss, Detlef; Weis, Patrick; Neiss, Christian; Weigend, Florian; Kappes, Manfred M.

    2012-04-01

    The structures of bismuth cluster cations in the range between 4 and 14 atoms have been assigned by a combination of gas phase ion mobility and trapped ion electron diffraction measurements together with density functional theory calculations. We find that above 8 atoms the clusters adopt prolate structures with coordination numbers between 3 and 4 and highly directional bonds. These open structures are more like those seen for clusters of semiconducting-in-bulk elements (such as silicon) rather than resembling the compact structures typical for clusters of metallic-in-bulk elements. An accurate description of bismuth clusters at the level of density functional theory, in particular of fragmentation pathways and dissociation energetics, requires taking spin-orbit coupling into account. For n = 11 we infer that low energy isomers can have fragmentation thresholds comparable to their structural interconversion barriers. This gives rise to experimental isomer distributions which are dependent on formation and annealing histories.

  7. Bismuth film electrodes for heavy metals determination

    NASA Astrophysics Data System (ADS)

    Rehacek, Vlastimil; Hotovy, Ivan; Vojs, Marian; Mika, Fedor

    2007-05-01

    Bismuth film electrodes (BiFEs) have a potential to replace toxic mercury used most frequently for determination of heavy metals (Cd, Pb, Zn) by anodic stripping voltammetry. We prepared a graphite disc electrode (0.5 mm in diameter) from a pencil-lead rod and developed a nitrogen doped diamond-like carbon (NDLC) microelectrode array consisting of 50 625 microdiscs with 3 μm in diameter and interelectrode distances of 20 μm on a highly conductive silicon substrate as a support for BiFEs. The disc graphite BiFE was used for simultaneous determination of Pb(II), Cd(II) and Zn(II) by square wave voltammetry (SWV) in an aqueous solution. We found the optimum bismuth-to-metal concentration ratio in the solution to be 20. The dependence of the stripping responses on the concentration of target metals was linear in the range from 1×10 -8 to 1.2×10 -7 mol/L. Detection limits 2.4×10 -9 mol/L for Pb(II), 2.9×10 -9 mol/L for Cd(II) and 1.2×10 -8 mol/L for Zn(II) were estimated. A bismuth-plated NDLC microelectrode array was used for Pb(II) determination by differential pulse voltammetry (DPV) in an aqueous solution. We found that the stripping current for bismuth-plated NDLC array was linear in the concentration range of Pb(II) from 2×10 -8 to 1.2×10 -7 mol/L. The detection limit 2.2×10 -8 mol/L was estimated from a calibration plot.

  8. Cryogenic exciter

    DOEpatents

    Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  9. Hall-Effect Thruster Utilizing Bismuth as Propellant

    NASA Technical Reports Server (NTRS)

    Szabo, James; Gasdaska, Charles; Hruby, Vlad; Robin, Mike

    2008-01-01

    A laboratory-model Hall-effect spacecraft thruster was developed that utilizes bismuth as the propellant. Xenon was used in most prior Hall-effect thrusters. Bismuth is an attractive alternative because it has a larger atomic mass, a larger electron-impact-ionization cross-section, and is cheaper and more plentiful.

  10. 21 CFR 520.1204 - Kanamycin, bismuth subcarbonate, activated attapulgite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Kanamycin, bismuth subcarbonate, activated... § 520.1204 Kanamycin, bismuth subcarbonate, activated attapulgite. (a) Specifications—(1) Each 5 milliliters (mL) of suspension contains 100 milligrams (mg) kanamycin (as the sulfate), 250 mg...

  11. 21 CFR 520.1204 - Kanamycin, bismuth subcarbonate, activated attapulgite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Kanamycin, bismuth subcarbonate, activated... § 520.1204 Kanamycin, bismuth subcarbonate, activated attapulgite. (a) Specifications—(1) Each 5 milliliters (mL) of suspension contains 100 milligrams (mg) kanamycin (as the sulfate), 250 mg...

  12. 21 CFR 520.1204 - Kanamycin, bismuth subcarbonate, activated attapulgite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Kanamycin, bismuth subcarbonate, activated... § 520.1204 Kanamycin, bismuth subcarbonate, activated attapulgite. (a) Specifications—(1) Each 5 milliliters (mL) of suspension contains 100 milligrams (mg) kanamycin (as the sulfate), 250 mg...

  13. 21 CFR 520.1204 - Kanamycin, bismuth subcarbonate, activated attapulgite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... milliliters (mL) of suspension contains 100 milligrams (mg) kanamycin (as the sulfate), 250 mg bismuth subcarbonate, and 500 mg activated attapulgite (aluminum magnesium silicate). (2) Each tablet contains 100 mg kanamycin (as the sulfate), 250 mg bismuth subcarbonate, and 500 mg activated attapulgite. (b) Sponsor....

  14. 21 CFR 520.1204 - Kanamycin, bismuth subcarbonate, activated attapulgite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... milliliters (mL) of suspension contains 100 milligrams (mg) kanamycin (as the sulfate), 250 mg bismuth subcarbonate, and 500 mg activated attapulgite (aluminum magnesium silicate). (2) Each tablet contains 100 mg kanamycin (as the sulfate), 250 mg bismuth subcarbonate, and 500 mg activated attapulgite. (b) Sponsor....

  15. Optical analysis of samarium doped sodium bismuth silicate glass

    NASA Astrophysics Data System (ADS)

    Thomas, V.; Sofin, R. G. S.; Allen, M.; Thomas, H.; Biju, P. R.; Jose, G.; Unnikrishnan, N. V.

    2017-01-01

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3 +‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices.

  16. Gastroprotective effect of ranitidine bismuth citrate is associated with increased mucus bismuth concentration in rats.

    PubMed Central

    Tanaka, S; Guth, P H; Paulsen, G; Kaunitz, J D

    1996-01-01

    BACKGROUND: Antisecretory and bismuth compounds protect the gastric mucosa from injury resulting from non-steroidal anti-inflammatory drugs. AIM: To study the mechanism underlying the gastroprotective effects of ranitidine bismuth citrate (GG311) in rats. METHODS: Indomethacin rat injury model and in vivo microscopy in which acid output, surface cell intracellular pH (pHi), gastric mucus gel thickness, and mucosal blood flow were measured simultaneously. RESULTS: In injury studies, GG311 dose dependently protected against severe injury induced by indomethacin (60 mg/kg subcutaneously). In in vivo microscopic studies, indomethacin significantly decreased mucus gel thickness and increased the initial rate of acidification of gastric surface cells when the superfusate pH was lowered from 7.4 to 1.0, and impaired pHi during acid exposure. Indomethacin had no effect on mucosal blood flow or acid output. GG311 alone had no effect on gel thickness, blood flow, or pHi homeostasis during acid exposure, but improved the initial acidification rate and pHi during superfusion with pH 1.0 solutions in the presence of indomethacin. In separate experiments, indomethacin pretreatment considerably increased gastric mucus bismuth concentrations in rats given GG311. CONCLUSIONS: The gastroprotective effect of GG311 against indomethacin induced gastric injury is associated with high and prolonged gastric mucus bismuth concentrations, which may impair proton permeation across the mucus gel. PMID:8977335

  17. High T(sub c) thin film superconductors: Preparation, patterning and characterization

    NASA Astrophysics Data System (ADS)

    Azoulay, J.

    A conventional oil-pumped vacuum system equipped with resistively heated tungsten boat sources was used for evaporation of bismuth- or yttrium-based cuprates for high T(sub c) thin film superconductors. A well-ground mixture with atomic proportions of bismuth, SrF2, CaF2 and copper for bismuth-based material, and of YF3, BaF2 and copper for yttrium-based material, was inserted into the boat and then resistively evaporated onto different substrates such as MgO, ZrO2 and SrTiO3 kept at room temperature. Yttrium-based thin films were found to have a better quality upon reduction of fluorine in the constituents. Thus, films prepared with an yttrium BaF2 and copper mixture show a metallic-like behavior, sharper transition and higher zero-resistance temperature as compared with that of films obtained by using a YF2 constiuent instead of yttrium. Bismuth-based thin films were found to lose bismuth during heat treatment unless the copper constiuent ended the evaporation process and was subsequently fully oxidized at 400 C. Bismuth-based patterned films were easily obtained by using a lift-off photolithographic method. Typical thickness of the films was measured to be about 0.5 micron after heat treatment.

  18. First-Principles Calculation of Femtosecond Symmetry-Breaking Atomic Forces in Photoexcited Bismuth

    NASA Astrophysics Data System (ADS)

    Murray, Éamonn D.; Fahy, Stephen

    2015-02-01

    We present a first-principles method for the calculation of the polarization-dependent atomic forces resulting from optical excitation in a solid. We calculate the induced force driving the Eg phonon mode in bismuth immediately after absorption of polarized light. When radiation with polarization perpendicular to the c axis is absorbed, the photoexcited charge density breaks the threefold rotational symmetry, leading to an atomic force component perpendicular to the axis. We calculate the initial excited electronic distribution as a function of photon energy and polarization and find the resulting atomic force components parallel and perpendicular to the axis. The magnitude of the calculated force is in excellent agreement with that derived from recent measurements of the amplitude of Eg atomic motion and the decay time of several femtoseconds for the driving force.

  19. An evaluated neutronic data file for bismuth

    SciTech Connect

    Guenther, P.T.; Lawson, R.D.; Meadows, J.W.; Smith, A.B.; Smith, D.L.; Sugimoto, M. ); Howerton, R.J. )

    1989-11-01

    A comprehensive evaluated neutronic data file for bismuth, extending from 10{sup {minus}5} eV to 20.0 MeV, is described. The experimental database, the application of the theoretical models, and the evaluation rationale are outlined. Attention is given to uncertainty specification, and comparisons are made with the prior ENDF/B-V evaluation. The corresponding numerical file, in ENDF/B-VI format, has been transmitted to the National Nuclear Data Center, Brookhaven National Laboratory. 106 refs., 10 figs., 6 tabs.

  20. Aging phenomenon of stabilized bismuth oxides

    SciTech Connect

    Jiang, N.; Buchanan, R.M.; Henn, F.E.G.; Marshall, A.F.; Stevenson, D.A. . Dept. of Materials Science and Engineering); Washsman, E.D. . Materials Research Center)

    1994-03-01

    Stabilized bismuth oxides exhibit a decay in conductivity when annealed at temperatures below 600 C. The authors refer to this phenomenon as aging and it is distinct from a conventional crystallographic phase transformation. This phenomenon is revealed by an endotherm from DSC thermal analysis and results in the formation of a superstructure observable by TEM diffraction patterns, yet no change in structure is observable by XRD. Since oxygen vacancies are the mobile defects responsible for ionic conductivity, the authors attribute the aging process to the ordering of oxygen vacancies by an order-disorder transition below [approximately]600 C.

  1. Exciter switch

    NASA Technical Reports Server (NTRS)

    Mcpeak, W. L.

    1975-01-01

    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  2. Excitation and propagation of X-ray fluorescence through thin devices with hollowed ordered structures: comparison of experimental and theoretical spectra.

    PubMed

    Mazuritskiy, M I; Dabagov, S B; Marcelli, A; Lerer, A M; Dziedzic-Kocurek, K

    2016-01-01

    The lack of models describing the propagation of X-rays in waveguides and the interference mechanism between incident and reflected radiation waves hamper the understanding and the control of wave propagation phenomena occurring in many real systems. Here, experimental spectra collected at the exit of microchannel plates (MCPs) under the total X-ray reflection condition are presented. The results are discussed in the framework of a theoretical model in which the wave propagation is enhanced by the presence of a transition layer at the surface. The angular distributions of the propagating radiation at the exit of these MCPs with microchannels of ∼3 µm diameter will also be presented and discussed. These spectra show contributions associated with the reflection of the primary monochromatic beam and with the fluorescence radiation originating from the excitation of atoms composing the surface of the microchannel. The soft X-ray fluorescence spectra collected at the exit of microcapillaries were analyzed in the framework of a wave approximation while diffraction contributions observed at the exit of these hollow X-ray waveguides have been calculated using the Fraunhofer diffraction model for waves in the far-field domain. Data collected at the Si L-edge show that in glassy MCPs the fluorescence radiation can be detected only when the energy of the primary monochromatic radiation is above the absorption edge for grazing angles higher than half of the critical angle of the total reflection phenomenon. Experimental data and simulations of the propagating radiation represent a clear experimental confirmation of the channeling phenomenon of the excited fluorescence radiation inside a medium and point out that a high transmission can be obtained in waveguide optics for parameters relevant to X-ray imaging.

  3. Design and fabrication technology of thinned backside-excited CCD imagers and the family of the intensified electron-bombarded CCD image tubes

    NASA Astrophysics Data System (ADS)

    Dalinenko, Ilia N.; Malyarov, Alexandre V.; Vishnevsky, Grigory I.; Vydrevitch, Michail G.; Kossov, Vladimir G.; Lazovsky, Leonid Y.; Golovkin, Sergei V.

    1995-09-01

    This paper sums up the results of more than 10 years of experience in design and manufacturing of thinned back-side illuminated CCDs of different types. Based upon the EB- CCDs created, the family of intensified electron-bombardment CCD image tubes has been designed, fabricated, and tested. This family includes: the single-stage Gen I EB-CCD devices with the 532(superscript *)580 and 780(superscript *)580 pixels CCDs; the 'hybrid' (the EB-CCD tube plus Gen I image intensifier) devices; and the EB-CCD tubes with the 40 mm photocathode and image demagnification factor 3 to 1. The results of the tests of these devices are presented and discussed. Besides this, the near future projects concerning EB-CCD tubes with the 80 mm photocathode and with image demagnification factor 5 to 1, and EB-CCD tubes with solar blind photocathods for the UV and EUV applications are briefly described.

  4. Design and fabrication technology of thinned backside-excited CCD imagers and the family of intensified electron-bombarded CCD image tubes

    NASA Astrophysics Data System (ADS)

    Dalinenko, Ilia N.; Malyarov, Alexandre V.; Vishnevsky, Grigory I.; Vydrevitch, Michail G.; Kossov, Vladimir G.; Lazovsky, Leonid Y.; Golovkin, Sergei V.

    1996-04-01

    This paper sums up the results of more than 10 years experience in design and manufacturing of thinned backside illuminated CCDs of different types. Based upon the EB-CCDs created, the family of intensified electron-bombarded CCD image tubes has been designed, fabricated and tested. This family includes: the single-stage Gen I-type EB-CCD devices with the 532*580 and 780*580 pixels CCDs; the `hybrid' (the EB-CCD tube plus Gen I image intensifier) devices; and the EB-CCD tubes with the 40 mm photocathode and image demagnification factor 3:1. The results of tests of these devices are presented and discussed. Besides, the near future projects concerning EB-CCD tubes with the 80 mm photocathode and with image demagnification factor 5:1, and EB-CCD tubes with solar blind photocathodes for the UV and EUV applications are briefly described.

  5. Design and fabrication technology of thinned backside-excited CCD imagers and the family of the electron-bombarded CCD image tubes

    NASA Astrophysics Data System (ADS)

    Dalinenko, I.; Kossov, V.; Kozlov, V.; Lazovsky, L.; Malyarov, A.; Vishnevsky, G.; Vydrevitch, M.; Zhuk, A.; Golovkin, S.

    1997-02-01

    The results of more than 10 years experience in design and manufacturing of thinned backside illuminated CCDs of different types are summed up. Based upon the EB CCDs created, the family of intensified electron-bombarded CCD image tubes has been designed, fabricated and tested. This family includes: the single-stage Gen I type EB CCD devices with the 532 × 580 and 780 × 580 pixels CCDs; the ``hybrid'' (the EB CCD tube plus Gen I image intensifier) devices; and the EB CCD tubes with the 40 mm photocathode and image demagnification factor 3:1. The results of tests of these devices are presented and discussed. Besides, the near future projects concerning EB CCD tubes with 80 mm photocathode and with image demagnification factor 5:1, the EB CCD tubes with solar blind photocathodes for the UV and EUV applications are briefly described.

  6. Development of a direct evaporation bismuth Hall thruster

    NASA Astrophysics Data System (ADS)

    Massey, Dean Richard

    Hall thrusters have been under active development around the world since the 1960's. Thrusters using traditional propellants such as xenon have been flown on a variety of satellite orbit raising and maintenance missions with an excellent record. To expand the mission envelope, it is necessary to lower the specific impulse of the thrusters but xenon and krypton are poor performers at specific impulses below 1,200 seconds. To enhance low specific impulse performance, this dissertation examines the development of a Hall-effect thruster which uses bismuth as a propellant. Bismuth, the heaviest non-radioactive element, holds many advantages over noble gas propellants from an energetics as well as a practical economic standpoint. Low ionization energy, large electron-impact cross-section and high atomic mass make bismuth ideal for low-specific impulse applications. The primary disadvantage lies in the high temperatures which are required to generate the bismuth vapors. Previous efforts carried out in the Soviet Union relied upon the complete bismuth vaporization and gas phase delivery to the anode. While this proved successful, the power required to vaporize and maintain gas phase throughout the mass flow system quickly removed many of the efficiency gains expected from using bismuth. To solve these problems, a unique method of delivering liquid bismuth to the anode has been developed. Bismuth is contained within a hollow anode reservoir that is capped by a porous metallic disc. By utilizing the inherent waste heat generated in a Hall thruster, liquid bismuth is evaporated and the vapors pass through the porous disc into the discharge chamber. Due to the high temperatures and material compatibility requirements, the anode was fabricated out of pure molybdenum. The porous vaporizer was not available commercially so a method of creating a refractory porous plate with 40-50% open porosity was developed. Molybdenum also does not respond well to most forms of welding so a

  7. Possible nuclear decay of bismuth induced by a mechanical impact

    NASA Astrophysics Data System (ADS)

    Marakhtanov, M. K.

    2016-09-01

    It is experimentally shown that the metallic dust after the inertial explosion induced by the impact of a metallic bismuth striker on a fixed steel barrier contains platinum and boron, which were absent before the explosion. The existence of platinum and boron is qualitatively determined. The emission of single 8-MeV α particles is also detected from the metallic dust that forms at the site of the impact interaction of bismuth with steel. Both effects point to possible nuclear decay of bismuth due to the energy of a mechanical impact.

  8. Effects of annealing electrodeposited bismuth Telluride films

    NASA Technical Reports Server (NTRS)

    Snyder, J.; Stoltz, N. G.

    2002-01-01

    Thermoelectric thin films exhibit different qualities when compared with bulk materials. The goal however is to achieve thermoelectric properties of bulk materials from electrodeposited thin films. Thin films are produced by electrochemical deposition at room temperature. In order to optimize thermoelectric figure of merit proper carrierconcentration must be obtained.

  9. Cryogenic Thermoelectric Properties of the Bismuth-Magnesium and Bismuth-Antimony-Magnesium Systems

    NASA Astrophysics Data System (ADS)

    Orovets, Christine; Jin, Hyungyu; Wiendlocha, Bartlomiej; Heremans, Joseph P.

    2012-02-01

    There is a need to increase the Figure of Merit of thermoelectric materials used in low temperature cooling applications. Band structure calculations show that substitutional magnesium in bismuth can form sharp density of states peaks, suggesting the presence of a resonant level. Single crystal samples of (Bi1-xSbx)1-yMgy (0 <= x <= 12% and 0 <= y <= 0.7% nominally) were synthesized in evacuated ampoules. The composition of each ingot was analyzed using x-ray diffraction, and transport properties were measured using a Thermal Transport Option (TTO) in a Physical Properties Measurement System (PPMS) from 300K to 2K. It is apparent that the addition of magnesium strongly influences thermopower; the data for Bi90Sb10Mg0.7 shows a second minimum in thermopower at 20K, in addition to the expected minimum at approximately 50-60K. This could be due to the resonant scattering at the cryogenic temperatures which arises from the excess density of states. The addition of magnesium also appears to decrease thermal conductivity below 30K. We present systematic experimental approaches and the results to elucidate the role of magnesium in bismuth and bismuth-antimony systems.

  10. Dielectric investigations of polycrystalline samarium bismuth ferrite ceramic

    SciTech Connect

    Palaimiene, E.; Macutkevic, J.; Banys, J.; Karpinsky, D. V.; Kholkin, A. L.

    2015-01-05

    Results of broadband dielectric investigations of samarium doped bismuth ferrite ceramics are presented in wide temperature range (20–800 K). At temperatures higher than 400 K, the dielectric properties of samarium bismuth ferrite ceramics are governed by Maxwell-Wagner relaxation and electrical conductivity. The DC conductivity increases and activation energy decreases with samarium concentration. In samarium doped bismuth ferrite, the ferroelectric phase transition temperature decreases with samarium concentration and finally no ferroelectric order is observed at x = 0.2. At lower temperatures, the dielectric properties of ferroelectric samarium doped bismuth ferrite are governed by ferroelectric domains dynamics. Ceramics with x = 0.2 exhibit the relaxor-like behaviour.

  11. Advanced Thin Ionization Calorimeter (ATIC)

    NASA Technical Reports Server (NTRS)

    Wefel, John P.

    1998-01-01

    This is the final report for NASA grant NAGW-4577, "Advanced Thin Ionization Calorimeter (ATIC)". This grant covered a joint project between LSU and the University of Maryland for a Concept Study of a new type of fully active calorimeter to be used to measure the energy spectra of very high energy cosmic rays, particularly Hydrogen and Helium, to beyond 1014 eV. This very high energy region has been studied with emulsion chamber techniques, but never investigated with electronic calorimeters. Technology had advanced to the point that a fully active calorimeter based upon Bismuth Germanate (BGO) scintillating crystals appeared feasible for balloon flight (and eventually space) experiments.

  12. Tripotassium dicitrato bismuthate enemas in the treatment of ulcerative proctitis.

    PubMed

    Srivastava, E D; Swift, G L; Wilkinson, S; Williams, G T; Evans, B K; Rhodes, J

    1990-12-01

    Eleven patients with active proctitis or proctosigmoiditis completed one month's treatment with tripotassium dicitrato bismuthate enemas administered at night. Symptoms, sigmoidoscopic appearances, and the histological grade of acute inflammation were assessed at the commencement of therapy and after one month. An overall score of these features showed improvement in 9 of 11 patients, which encourages further investigation of bismuth in controlled trials for patients with inflammatory bowel disease.

  13. Highly ytterbium-doped bismuth-oxide-based fiber.

    PubMed

    Ohara, Seiki; Kuroiwa, Yutaka

    2009-08-03

    Thermally stable highly ytterbium-doped bismuth-oxide-based glasses have been investigated. The absorbance increased linearly with Yb(2)O(3) concentration, reaching 7800 dB/m with 3 mol-% of Yb(2)O(3). An ytterbium-doped bismuth-oxide-based fiber has also been fabricated with a fiber loss of 0.24 dB/m. A fiber laser is also demonstrated, and it shows a slope efficiency of 36%.

  14. Studies on the absorption and excretion of tripotassium dicitrato-bismuthate in man.

    PubMed

    Lee, S P

    1981-11-01

    In 8 volunteers blood and urine bismuth levels were detected after a 5-day course of tripotassium dicitrato-bismuthate and rose further with increasing dose. In 24 patients, blood and urine bismuth were measured on the last day of treatment. There was no significant difference (p greater than 0.2) in either blood or urine bismuth levels amongst patients treated for 4,5 or 6 weeks with colloidal bismuth. None of the blood level measurements exceeded 50 micrograms/l. Bismuth was slowly eliminated in the urine after stopping treatment.

  15. Exciting Pools

    ERIC Educational Resources Information Center

    Wright, Bradford L.

    1975-01-01

    Advocates the creation of swimming pool oscillations as part of a general investigation of mechanical oscillations. Presents the equations, procedure for deriving the slosh modes, and methods of period estimation for exciting swimming pool oscillations. (GS)

  16. Excited waves in shear layers

    NASA Technical Reports Server (NTRS)

    Bechert, D. W.

    1982-01-01

    The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

  17. Tripotassium dicitrato bismuthate: absorption and urinary excretion of bismuth in patients with normal and impaired renal function.

    PubMed

    Treiber, G; Gladziwa, U; Ittel, T H; Walker, S; Schweinsberg, F; Klotz, U

    1991-10-01

    We have investigated the absorption and urinary excretion of tripotassium dicitrato bismuthate during a treatment course of 4 weeks in 7 patients with normal renal function (creatinine clearance 115 +/- 29 ml/min; mean +/- S.D.), in 7 patients with impaired renal function (creatinine clearance = 34 +/- 19 ml/min) and in 4 dialysed patients. Following the first dose of tripotassium dicitrato bismuthate (216 mg bismuth b.d.), and after 2 and 4 weeks of treatment (dialysed patients received only 108 mg/b.d.), plasma and urine concentrations of bismuth were monitored for 2 and 24 h, respectively. After stopping therapy plasma and urine concentrations of bismuth were followed for 4 and 6 weeks, respectively. In all three groups of patients small amounts of bismuth (mean values 0.26 to 0.28% of dose) were rapidly (transient mean peak concentrations between 40 and 134 micrograms/L) reached within about 30 to 40 min, absorbed and plasma levels demonstrated a wide intra- and inter-individual variability. Absorption profiles were not altered during the treatment course; however, the trough plasma concentration of bismuth demonstrated an about 3- to 5-fold accumulation (correlated to creatinine clearance) from about 5 micrograms/L to 15 micrograms/L (normal renal function) or to 20-25 micrograms/L (impaired renal function). Pre-study bismuth levels could be detected within 2 to 4 weeks after stopping therapy in all subjects whereas urinary concentrations were still elevated 6 weeks after the course of treatment. Our results indicate that tripotassium dicitrato bismuthate is absorbed in very low amounts during standard therapy. However, dependent on renal function, accumulation to non-toxic levels does occur during a course of treatment. It appears prudent to halve tripotassium dicitrato bismuthate dosage in patients with severe renal insufficiency (creatinine clearance less than or equal to 20 ml/min) to avoid any possible toxic risks. In such patients monitoring of the

  18. Bismuth(III) volatilization and immobilization by filamentous fungus Aspergillus clavatus during aerobic incubation.

    PubMed

    Boriová, Katarína; Urík, Martin; Bujdoš, Marek; Matúš, Peter

    2015-02-01

    As with many metals, bismuth can be accumulated or transformed by microorganisms. These interactions affect microbial consortia and bismuth environmental behaviour, mobility, and toxicity. Recent research focused specifically on bismuth anaerobic transformation by bacteria and archaea has inspired the evaluation of the mutual interactions between bismuth and filamentous fungi as presented in this article. The Aspergillus clavatus fungus proved resistant to adverse effects from bismuth contamination in culture medium with up to a concentration of 195 µmol L(-1) during static 15- and 30-day cultivation. The examined resistance mechanism includes biosorption to the fungal surface and biovolatilization. Pelletized fungal biomass has shown high affinity for dissolved bismuth(III). Bismuth biosorption was rapid, reaching equilibrium after 50 min with a 0.35 mmol g(-1) maximum sorption capacity as calculated from the Langmuir isotherm. A. clavatus accumulated ≤70 µmol g(-1) of bismuth after 30 days. Preceding isotherm study implications that most accumulated bismuth binds to cell wall suggests that biosorption is the main detoxification mechanism. Accumulated bismuth was also partly volatilized (≤1 µmol) or sequestrated in the cytosol or vacuoles. Concurrently, ≤1.6 µmol of bismuth remaining in solution was precipitated by fungal activity. These observations indicate that complex mutual interactions between bismuth and filamentous fungi are environmentally significant regarding bismuth mobility and transformation.

  19. Enhancement of bismuth antibacterial activity with lipophilic thiol chelators.

    PubMed Central

    Domenico, P; Salo, R J; Novick, S G; Schoch, P E; Van Horn, K; Cunha, B A

    1997-01-01

    The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of

  20. Large magneto-optic enhancement in ultra-thin liquid-phase-epitaxy iron garnet films

    SciTech Connect

    Levy, Miguel; Chakravarty, A.; Huang, H.-C.; Osgood, R. M.

    2015-07-06

    Significant departures from bulk-like magneto-optic behavior are found in ultra-thin bismuth-substituted iron-garnet films grown by liquid-phase-epitaxy. These changes are due, at least in part, to geometrical factors and not to departures from bulk-composition in the transient layer at the film-substrate interface. A monotonic increase in specific Faraday rotation with reduced thickness is the signature feature of the observed phenomena. These are traced to size-dependent modifications in the diamagnetic transition processes responsible for the Faraday rotation. These processes correspond to the electronic transitions from singlet {sup 6}S ground states to spin-orbit split excited states of the Fe{sup 3+} ions in the garnet. A measurable reduction in the corresponding ferrimagnetic resonance linewidths is found, thus pointing to an increase in electronic relaxation times and longer lived excitations at reduced thicknesses. These changes together with a shift in vibrational frequency of the Bi-O bonds in the garnet at reduced thicknesses result in greatly enhanced magneto-optical performance. These studies were conducted on epitaxial monocrystalline Bi{sub 0.8}Gd{sub 0.2}Lu{sub 2}Fe{sub 5}O{sub 12} films.

  1. Luminescence properties of Sm{sup 3+} impurities in strontium lithium bismuth borate glasses

    SciTech Connect

    Rajesh, D.; Ratnakaram, Y. C.; Seshadri, M.; Balakrishna, A.

    2012-06-05

    In the present work, different concentrations of Sm{sup 3+}-doped strontium lithium bismuth borate glasses (SLBiB) were prepared by melt quench technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Using the J-O intensity parameters, emission and decay measurements various radiative properties are studied. The nature of decay curves of {sup 4}G{sub 5/2} level for different Sm{sup 3+} ion concentrations in SLBiB glasses has been analyzed. The intensities of observed emission peaks and measured lifetimes decrease with the increase of Sm{sup 3+} ion concentration which may be due to energy transfer between excited Sm{sup 3+} ions through cross-relaxations and resonant energy channels.

  2. Optical properties and ultrafast optical nonlinearity of Yb3+ doped sodium borate and bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Karthikeyan, B.; Suchand Sandeep, C. S.; Cha, Jaemine; Takebe, Hiromichi; Philip, Reji; Mohan, S.

    2008-05-01

    In this paper, we report the optical and ultrafast nonlinear optical properties of Yb3+ doped sodium borate and bismuthate glasses. The glasses have been prepared through the melt quench technique. Optical absorption measurements show compositional dependent absorption spectrum of Yb3+, which is due to the higher crystal field induced by Bi3+ ions. Local structure of the glasses has been identified by using Fourier transform infrared and Raman studies. From open aperture z-scan measurements done by using 100 fs laser pulses, the ultrafast optical nonlinearity in these materials is calculated at the nonresonant excitation wavelength of 800 nm. The measured three-photon absorption originates from the glass host, with contributions from the nonbridging oxygens and the nonlinear electronic polarization of the Bi3+ ions.

  3. Electrospun bismuth ferrite nanofibers for potential applications in ferroelectric photovoltaic devices.

    PubMed

    Fei, Linfeng; Hu, Yongming; Li, Xing; Song, Ruobing; Sun, Li; Huang, Haitao; Gu, Haoshuang; Chan, Helen L W; Wang, Yu

    2015-02-18

    Bismuth ferrite (BFO) nanofibers were synthesized via a sol-gel-based electrospinning process followed by thermal treatment. The influences of processing conditions on the final structure of the samples were investigated. Nanofibers prepared under optimized conditions were found to have a perovskite structure with good quality of crystallization and free of impurity phase. Ferroelectric and piezoelectric responses were obtained from individual nanofiber measured on a piezoelectric force microscope. A prototype photovoltaic device using laterally aligned BFO nanofibers and interdigital electrodes was developed and its performance was examined on a standard photovoltaic system. The BFO nanofibers were found to exhibit an excellent ferroelectric photovoltaic property with the photocurrent several times larger than the literature data obtained on BFO thin films.

  4. Substitution effects on bismuth based multifunctional materials

    NASA Astrophysics Data System (ADS)

    Krezhov, Kiril; Kovachev, Stefan; Svab, Erzsebet

    Described are our targeted experiments to improve understanding of some key aspects of the mechanisms contributing to intrinsic effects such as the magnetoelectric coupling in oxides. The magnetoelectric materials have long been of interest because of useful combinations of electrical, magnetic, optical and catalytic properties. Particularly spectacular are the manganites(M=Mn) for which apart from the strong magnetoresistance (MR) effect another striking feature is the occurrence of charge and orbital ordering (CO-OO) effects connected with the specific orbital orientation and the spatial arrangement of the eg orbitals. The MR and CO-OO effects are a manifestation of the strong interplay between the orbital, charge, and spin degrees of freedom in these systems and in some cases gives rise to multiferroicity. In this regard, some of our research is on new ABO3, AB2O5 and double perovskites A2BB'O6 containing p elements with lone pair electrons such as Bi3+. Bismuth creates irregular oxygen coordination environment and to stabilize its valence state often requires the use of high pressure or specific soft chemistry. Studied are the effects of cationic substitution on the structural parameters of the perovskites (Bi1-yRy)1-xAxMnO3 (R = rare earth; A= Ca2+, Sr2+; x,y=0.5), BiFexMn2-xO5, La1-xBiXMn2O5 etc. Ab-initio density functional theory calculations were performed to study the structure, magnetic and optical properties of multiferroic BiFeO3, also modified with La3+ and Mn3+. Synthesized and characterized is a new bismuth oxide - multiferroic BiFe2O5-δ A number of studies continue to address this class of materials and related-type materials such as cobaltites, chromites and ferrites, much of the work being driven by the potential applications as electrode materials in solid oxide fuel cells, exhaust gas sensors, membranes for separation processes or as catalysts but lately new functionalities emerge and are in the focus for use in electronics and information

  5. 40 CFR 471.10 - Applicability; description of the lead-tin-bismuth forming subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-tin-bismuth forming subcategory. 471.10 Section 471.10 Protection of Environment ENVIRONMENTAL... METAL POWDERS POINT SOURCE CATEGORY Lead-Tin-Bismuth Forming Subcategory § 471.10 Applicability; description of the lead-tin-bismuth forming subcategory. This subpart applies to discharges of pollutants...

  6. 40 CFR 471.10 - Applicability; description of the lead-tin-bismuth forming subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-tin-bismuth forming subcategory. 471.10 Section 471.10 Protection of Environment ENVIRONMENTAL... POINT SOURCE CATEGORY Lead-Tin-Bismuth Forming Subcategory § 471.10 Applicability; description of the lead-tin-bismuth forming subcategory. This subpart applies to discharges of pollutants to waters of...

  7. 40 CFR 471.10 - Applicability; description of the lead-tin-bismuth forming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-tin-bismuth forming subcategory. 471.10 Section 471.10 Protection of Environment ENVIRONMENTAL... METAL POWDERS POINT SOURCE CATEGORY Lead-Tin-Bismuth Forming Subcategory § 471.10 Applicability; description of the lead-tin-bismuth forming subcategory. This subpart applies to discharges of pollutants...

  8. 40 CFR 471.10 - Applicability; description of the lead-tin-bismuth forming subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-tin-bismuth forming subcategory. 471.10 Section 471.10 Protection of Environment ENVIRONMENTAL... METAL POWDERS POINT SOURCE CATEGORY Lead-Tin-Bismuth Forming Subcategory § 471.10 Applicability; description of the lead-tin-bismuth forming subcategory. This subpart applies to discharges of pollutants...

  9. Effect of bismuth telluride concentration on the thermoelectric properties of PEDOT:PSS-glycerol organic films

    NASA Astrophysics Data System (ADS)

    Rahman, Airul Azha Abd; Ali Umar, Akrajas; Othman, Mohamad Habrul Ulum

    2015-02-01

    In this work, the effect of bismuth-telluride concentration on the thermoelectric properties of PEDOT:PSS-Glycerol thin films is investigated. A thermoelectric device was fabricated by depositing the n-type and the p-type Bi2Te3 (BT) doped-PEDOT:PSS-Glycerol on a glass substrate via a spin coating method at 500 rpm. Room-temperature electrical properties characterization shows that the electrical conductivity of both type thin film increases with increasing of BT doping concentration and optimum at concentration of 0.8 wt% for both p-type and n-type thin films, i.e. 17.9 S/cm and 7.78 S/cm, respectively. However, the study of the temperature effect on the thin films electrical conductivity suggested that the thermoelectric properties of both types' samples improved with increasing of BT concentration and optimum at 0.8 and 0.6 wt% for p-type and n-type thin films, respectively. It then decreased if the BT concentration further increased. The Sebeeck coefficient for these samples is as high as -11.9 and -15.7 uV/K, which is equivalent to a power factors of 0.26 and 0.19 μS V2/ (m K2), respectively. A thermoelectric device resembling a thermocouple system that was fabricated using the optimum p-type and n-type thin films can generate a voltage as high as 1.1 V at a temperature difference as low as 55 K, which is equivalent to a maximum power of 6.026 μW at Vmax.power of 0.5489 V (for an estimated matched-load of 50 Ω). The present materials system is potential for powering low power consumption electronic devices.

  10. Ultrasonication of Bismuth Telluride Nanocrystals Fabricated by Solvothermal Method

    NASA Technical Reports Server (NTRS)

    Chu, Sang-Hyon; Choi, Sang H.; Kim, Jae-Woo; King, Glen C.; Elliott, James R.

    2006-01-01

    The objective of this study is to evaluate the effect of ultrasonication on bismuth telluride nanocrystals prepared by solvothermal method. In this study, a low dimensional nanocrystal of bismuth telluride (Bi2Te3) was synthesized by a solvothermal process in an autoclave at 180 C and 200 psi. During the solvothermal reaction, organic surfactants effectively prevented unwanted aggregation of nanocrystals in a selected solvent while controlling the shape of the nanocrystal. The atomic ratio of bismuth and tellurium was determined by energy dispersive spectroscopy (EDS). The cavitational energy created by the ultrasonic probe was varied by the ultrasonication process time, while power amplitude remained constant. The nanocrystal size and its size distribution were measured by field emission scanning electron microscopy (FESEM) and a dynamic light scattering system. When the ultrasonication time increased, the average size of bismuth telluride nanocrystal gradually increased due to the direct collision of nanocrystals. The polydispersity of the nanocrystals showed a minimum when the ultrasonication was applied for 5 min. Keywords: bismuth telluride, nanocrystal, low-dimensional, ultrasonication, solvothermal

  11. Bismuth(III) salts as synthetic tools in organic transformations.

    PubMed

    Yadav, J S; Antony, Aneesh; Reddy, Basi V Subba

    2012-01-01

    Bismuth is the heaviest stable element of the periodic table and even though it carries the status of heavy metal, it is rated as relatively nontoxic and noncarcinogenic unlike its neighboring elements. Additionally, the fact that it tolerates air and moisture makes the chemistry of bismuth attractive to synthetic chemists. The catalytic nature of this metal is attributed to the capability of its salts to acts as Lewis acids in reactions. The nontoxicity together with the ability to endure moisture makes bismuth compounds favorites of chemists and scientists who are concerned about environmental hazards, and such properties are highly desirable for scale-up of a method. The Lewis acidic nature of salts of this element have been thoroughly investigated in various types of reactions such as cycloaddition reactions, reactions of sugars, protection and deprotection reactions, synthesis of heterocyclic systems etc. Since the 1990s, various research groups have successfully utilized this catalytic nature for many organic transformations. Our group's contribution towards the development of methodologies that are useful in accomplishing various functional group manipulations by making use of the catalytic properties of bismuth salts is portrayed here. The mechanistic aspects and the catalytic efficiency of the bismuth(III) salts are accented together with the synthetic utility and the biological and pharmacological applications of the methodologies developed.

  12. Bismuth-norfloxacin complex: synthesis, physicochemical and antimicrobial evaluation.

    PubMed

    Shaikh, Anwar R; Giridhar, Rajani; Yadav, Mange Ram

    2007-03-06

    Norfloxacin is a fluoroquinolone antibacterial agent which is active against various Gram-positive as well as Gram-negative microorganisms. Presence of metal ions considerably alters the activity of fluoroquinolones against potentially susceptible bacteria. As bismuth is known to possess a good antibacterial activity, bismuth complex of norfloxacin was prepared by reacting bismuth citrate with aqueous solution of norfloxacin. The structure of the bismuth-norfloxacin complex (BNC) was confirmed by spectral, chemical and elemental analysis. Antimicrobial studies were carried out using agar diffusion method against Escherichia coli (ATCC 25922), Klebsiella pneumoniae (NTCC 10320), Staphylococcus aureus (ATCC 29213), Bacillus pumilis (NTCC 8241) and Staphylococcus epidermidis (ATCC 12228). The results showed significant increase (p<0.05, Tukeys test) in antibacterial activity of BNC as compared with norfloxacin and physical mixture of norfloxacin and bismuth citrate. This increase in activity is being considered due to increased bioavailability of the metal drug complex. Thus, the use of the BNC may be preferable over norfloxacin alone.

  13. Photoreductive generation of amorphous bismuth nanoparticles using polysaccharides--bismuth-cellulose nanocomposites.

    PubMed

    Breitwieser, Doris; Kriechbaum, Margit; Ehmann, Heike M A; Monkowius, Uwe; Coseri, Sergiu; Sacarescu, Liviu; Spirk, Stefan

    2015-02-13

    A simple and highly reproducible synthesis of amorphous bismuth nanoparticles incorporated into a polysaccharide matrix using a photoreduction process is presented. As precursor for the generation of the Bi nanoparticles, organosoluble triphenylbismuth is used. The precursor is dissolved in toluene and mixed with a hydrophobic organosoluble polysaccharide, namely trimethylsilyl cellulose (TMSC) with high DSSi. The solution is subjected to UV exposure, which induces the homolytic cleavage of the bismuth-carbon bond in BiPh3 resulting in the formation of Bi(0) and phenyl radicals. The aggregation of the Bi atoms can be controlled in the TMSC matrix and yields nanoparticles of around 20 nm size as proven by TEM. The phenyl radicals undergo recombination to form small organic molecules like benzene and biphenyl, which can be removed from the nanocomposite after lyophilization and exposure to high vacuum. Finally, the TMSC matrix is converted to cellulose after exposure to HCl vapors, which remove the trimethylsilyl groups from the TMSC derivative. Although TMSC is converted to cellulose, the formed TMS-OH is not leaving the nanocomposite but reacts instead with surface oxide layer of the Bi nanoparticles to form silylated Bi nanoparticles as proven by TEM/EDX.

  14. Ultrasound in lead-bismuth eutectic

    SciTech Connect

    Dierckx, M.; Van Dyck, D.

    2011-07-01

    The Belgian Nuclear Research Centre (SCK.CEN) is in the process of designing MYRRHA, a new multi-purpose irradiation facility to replace the ageing BR2. MYRRHA is a fast spectrum reactor cooled with lead-bismuth eutectic (LBE). As liquid metal is opaque to visual light, ultrasonic measurement techniques are selected to fulfill essential tasks that, according to our assessment, will be demanded by licensing authorities, in particular: fuel assembly identification and localization of a lost fuel assembly. To that end, a considerable research effort at SCK.CEN is devoted to study ultrasonic propagation in LBE. As ultrasonic experiments in LBE are elaborate and expensive to set up, we are particularly interested in to what extent experiments in water can be extrapolated to LBE - one of the main focuses of this article. We describe and present results of a first experiment with this goal which shows that the signal to noise ratio is better in LBE and that we even see small diffuse reflections up to 40 deg. off normal. On the other hand, we do not see internal reflections in stainless steel objects in LBE which we do in water. Therefore, we conclude that experiments in water can be used to validate algorithms for LBE on the condition that they do not rely on internal reflections. We also present solutions to tackle the essential tasks: fuel assembly identification and lost object localization. The requirements for the ultrasonic equipment implementing these solutions are also discussed. (authors)

  15. Integrated Liquid Bismuth Propellant Feed System

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.; Stanojev, Boris J.

    2006-01-01

    A prototype bismuth propellant feed and control system was constructed and tested. An electromagnetic pump was used in this system to provide fine control of the hydrostatic pressure, and a new type of in-line flow sensor was developed to provide an accurate, real-time measurement of the mass flow rate. High-temperature material compatibility was a driving design requirement for the pump and flow sensor, leading to the selection of macor for the main body of both components. Post-test inspections of both components revealed no cracks or leaking in either. In separate proof-of-concept experiments, the pump produced a linear pressure rise as a function of current that compared favorably with theoretical pump pressure predictions, with a pressure of 10 kPa at 30 A. Flow sensing was successfully demonstrated in a bench-top test using gallium as a substitute liquid metal. A real-time controller was successfully used to control the entire system, simultaneously monitoring all power supplies and performing data acquisition duties.

  16. Properties of unconventional lithium bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Hazra, S.; Mandal, S.; Ghosh, A.

    1997-10-01

    Unconventional bismuthate glasses containing lithium oxide have been prepared by a conventional melt-quench technique. X-ray diffraction, scanning electron microscopy, and differential thermal analysis show that stable binary glasses of composition xLi2O-(100-x)Bi2O3 can be achieved for x=20-35 mol %. Systematic variation of the glass-transition temperature, density, and molar volume observed in these glasses indicates no significant structural change with composition. Differential thermal analysis and optical studies show that the strength of the glass network decreases with the increase of Li2O content in the glass matrix with a small deviation for the extra stable 30Li2O-70Bi2O3 glass composition. Studies of Raman spectra and molar volume ensure that all glasses are built up of [BiO6] octahedral units, while the influence of Li+ ions in the glass matrix is also confirmed from optical, Raman, and electrical studies. Wide transmitting window in the optical region having sharp cutoffs in both ultraviolet-visible and infrared regimes may make these glasses useful in spectral devices. High dielectric values in these glasses compared to glasses formed with conventional glass former can be attributed to the influence of the high polarizability of the unconventional network forming cations, Bi3+.

  17. Investigation of Bismuth Triiodide (BiI3) for Photovoltaic Applications

    SciTech Connect

    Brandt, Riley E.; Kurchin, Rachel C.; Hoye, Robert L. Z.; Poindexter, Jeremy R.; Wilson, Mark W. B.; Sulekar, Soumitra; Lenahan, Frances; Yen, Patricia; Stevanovic, Vladan; Nino, Juan C.; Bawendi, Moungi G.; Buonassisi, Tonio

    2015-10-12

    We investigate bismuth triiodide (BiI3) as a candidate thin-film photovoltaic (PV) absorber. BiI3 was chosen for its optical properties and the potential for “defect-tolerant” charge transport properties, which we test experimentally by measuring optical absorption and recombination lifetimes. We synthesize phase-pure BiI3 thin films by physical vapor transport and solution processing and single-crystals by an electrodynamic gradient vertical Bridgman method. The bandgap of these materials is ~1.8 eV, and they demonstrate room-temperature band-edge photoluminescence. We measure monoexponential recombination lifetimes in the range of 180–240 ps for thin films, and longer, multiexponential dynamics for single crystals, with time constants up to 1.3 to 1.5 ns. We discuss the outstanding challenges to developing BiI3 PVs, including mechanical and electrical properties, which can also inform future selection of candidate PV absorbers.

  18. Dependence of optical properties of calcium bismuthates on synthesis conditions

    NASA Astrophysics Data System (ADS)

    Shtarev, D. S.; Shtareva, A. V.

    2016-08-01

    The article studies optical properties of calcium bismuthate nanoparticles of different composition. For the first time the synthesis of these compounds was produced by the pyrolysis of organic precursors using an organic solvent. Characterization of particles was made by scanning electron microscopy and X-ray analysis. The optical properties were investigated by diffuse reflectance spectroscopy (DRS). It is shown that the type of crystal lattice of the particles of calcium bismuthate determines the possibility to control the optical properties of nanoparticles by varying their composition. The conclusions about the production process and the composition of calcium bismuthate, the most promising for use as a photocatalyst of visible light and solar cells, were made.

  19. Isotopic generator for bismuth-212 and lead-212 from radium

    DOEpatents

    Atcher, Robert W.; Friedman, Arnold M.; Hines, John

    1987-01-01

    A method and apparatus for providing radionuclides of bismuth-212 and lead-212. Thorium-228 and carrier solution starting material is input to a radiologically contained portion of an isotopic generator system, and radium-224 is separated from thorium-228 which is retained by a strongly basic anion exchange column. The separated radium-224 is transferred to an accessible, strongly acidic cationic exchange column. The cationic column retains the radium-224, and natural radioactive decay generates bismuth-212 and lead-212. The cationic exchange column can also be separated from the contained portion of the system and utilized without the extraordinary safety measures necessary in the contained portion. Furthermore, the cationic exchange column provides over a relatively long time period the short lived lead-212 and bismuth-212 radionuclides which are useful for a variety of medical therapies.

  20. Excited baryons

    SciTech Connect

    Mukhopadhyay, N.C.

    1986-01-01

    The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)

  1. Bismuth-doped optical fibres: A new breakthrough in near-IR lasing media

    SciTech Connect

    Dianov, Evgenii M

    2012-09-30

    Recent results demonstrate that bismuth-doped optical fibres have considerable potential as near-IR active lasing media. This paper examines bismuth-doped fibres intended for the fabrication of fibre lasers and optical amplifiers and reviews recent results on the luminescence properties of various types of bismuth-doped fibres and the performance of bismuth-doped fibre lasers and optical amplifiers for the spectral range 1150 - 1550 nm. Problems are discussed that have yet to be solved in order to improve the efficiency of the bismuth lasers and optical amplifiers. (optical fibres, lasers and amplifiers. properties and applications)

  2. Compact and Integrated Liquid Bismuth Propellant Feed System

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Stanojev, Boris; Korman, Valentin; Gross, Jeffrey T.

    2007-01-01

    Operation of Hall thrusters with bismuth propellant has been shown to be a promising path toward high-power, high-performance, long-lifetime electric propulsion for spaceflight missions [1]. There has been considerable effort in the past three years aimed at resuscitating this promising technology and validating earlier experimental results indicating the advantages of a bismuth-fed Hall thruster. A critical element of the present effort is the precise metering of propellant to the thruster, since performance cannot be accurately assessed without an accurate accounting of mass flow rate. Earlier work used a pre./post-test propellant weighing scheme that did not provide any real-time measurement of mass flow rate while the thruster was firing, and makes subsequent performance calculations difficult. The motivation of the present work is to develop a precision liquid bismuth Propellant Management System (PMS) that provides hot, molten bismuth to the thruster while simultaneously monitoring in real-time the propellant mass flow rate. The system is a derivative of our previous propellant feed system [2], but the present system represents a more compact design. In addition, all control electronics are integrated into a single unit and designed to reside on a thrust stand and operate in the relevant vacuum environment where the thruster is operating, significantly increasing the present technology readiness level of liquid metal propellant feed systems. The design of various critical components in a bismuth PMS are described. These include the bismuth reservoir and pressurization system, 'hotspot' flow sensor, power system and integrated control system. Particular emphasis is given to selection of the electronics employed in this system and the methods that were used to isolate the power and control systems from the high-temperature portions of the feed system and thruster. Open loop calibration test results from the 'hotspot' flow sensor are reported, and results of

  3. Lead-bismuth eutectic technology for Hyperion reactor

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Kapernick, R. J.; McClure, P. R.; Trapp, T. J.

    2013-10-01

    A small lead-bismuth eutectic-cooled reactor concept (referred to as the Hyperion reactor concept) is being studied at Los Alamos National Laboratory and Hyperion Power Generation. In this report, a critical assessment of the lead-bismuth eutectic technology for Hyperion reactor is presented based on currently available knowledge. Included are: material compatibility, oxygen control, thermal hydraulics, polonium control. The key advances in the technology and their applications to Hyperion reactor design are analyzed. Also, the near future studies in main areas of the technology are recommended for meeting the design requirements.

  4. Physical and Optical Polarizability and Transport Properties of Bismuthate Glasses

    NASA Astrophysics Data System (ADS)

    Bale, Shashidhar; Rahman, Syed

    Bismuth-based glasses containing ZnO, B2O3 and Li2O are investigated through different physical, polarizability and transport properties. Raman spectroscopy reveals that these glasses are built from [BiO3] and [BiO6] units. Zinc in tetrahedral form is also observed. Density and glass transition temperature increase with the bismuth content. The refractive index, oxide ion polarizability and optical basicity also increase with the Bi2O3 content, whereas the interaction parameter decreases. The DC electrical conductivity increases and the activation energy decreases with the increase in the Li2O content.

  5. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect

    Mukherjee, A. Banerjee, M. Basu, S.; Pal, M.

    2014-04-24

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  6. Correlation between thermoluminescence and radiation damage in bismuth germanate

    SciTech Connect

    Melcher, C.L.

    1985-02-01

    Thermoluminescence properties of bismuth germanate and their relationship to radiation damage characteristics have been investigated. Thermoluminescence and radiation damage in bismuth germanate display several similar properties including similar responses as a function of radiation dose, similar saturation levels, and similar decay times. Also a correlation was found between the thermoluminescence sensitivities and radiation damage sensitivities of four different crystals. The traps responsible for the radiation damage and those which store the thermoluminescence signal appear to be either closely related or actually the same traps. Four trapping centers can be seen in the thermoluminescence glow curves. The depth of the dominant trap is 1.1 eV. 10 references.

  7. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Mukherjee, A.; Banerjee, M.; Basu, S.; Pal, M.

    2014-04-01

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  8. Degradation of organic dyes via bismuth silver oxide initiated direct oxidation coupled with sodium bismuthate based visible light photocatalysis.

    PubMed

    Yu, Kai; Yang, Shaogui; Liu, Cun; Chen, Hongzhe; Li, Hui; Sun, Cheng; Boyd, Stephen A

    2012-07-03

    Organic dye degradation was achieved via direct oxidation by bismuth silver oxide coupled with visible light photocatalysis by sodium bismuthate. Crystal violet dye decomposition by each reagent proceeded via two distinct pathways, each involving different active oxygen species. A comparison of each treatment method alone and in combination demonstrated that using the combined methods in sequence achieved a higher degree of degradation, and especially mineralization, than that obtained using either method alone. In the combined process direct oxidation acts as a pretreatment to rapidly bleach the dye solution which substantially facilitates subsequent visible light photocatalytic processes. The integrated sequential direct oxidation and visible light photocatalysis are complementary manifesting a > 100% increase in TOC removal, compared to either isolated method. The combined process is proposed as a novel and effective technology based on one primary material, sodium bismuthate, for treating wastewaters contaminated by high concentrations of organic dyes.

  9. Hydrolysis studies on bismuth nitrate: synthesis and crystallization of four novel polynuclear basic bismuth nitrates.

    PubMed

    Miersch, L; Rüffer, T; Schlesinger, M; Lang, H; Mehring, M

    2012-09-03

    Hydrolysis of Bi(NO(3))(3) in aqueous solution gave crystals of the novel compounds [Bi(6)O(4)(OH)(4)(NO(3))(5)(H(2)O)](NO(3)) (1) and [Bi(6)O(4)(OH)(4)(NO(3))(6)(H(2)O)(2)]·H(2)O (2) among the series of hexanuclear bismuth oxido nitrates. Compounds 1 and 2 both crystallize in the monoclinic space group P2(1)/n but show significant differences in their lattice parameters: 1, a = 9.2516(6) Å, b = 13.4298(9) Å, c = 17.8471(14) Å, β = 94.531(6)°, V = 2210.5(3) Å(3); 2, a = 9.0149(3) Å, b = 16.9298(4) Å, c = 15.6864(4) Å, β = 90.129(3)°, V = 2394.06(12) Å(3). Variation of the conditions for partial hydrolysis of Bi(NO(3))(3) gave bismuth oxido nitrates of even higher nuclearity, [{Bi(38)O(45)(NO(3))(24)(DMSO)(26)}·4DMSO][{Bi(38)O(45)(NO(3))(24)(DMSO)(24)}·4DMSO] (3) and [{Bi(38)O(45)(NO(3))(24)(DMSO)(26)}·2DMSO][{Bi(38)O(45)(NO(3))(24)(DMSO)(24)}·0.5DMSO] (5), upon crystallization from DMSO. Bismuth oxido clusters 3 and 5 crystallize in the triclinic space group P1 both with two crystallographically independent molecules in the asymmetric unit. The following lattice parameters are observed: 3, a = 20.3804(10) Å, b = 20.3871(9) Å, c = 34.9715(15) Å, α = 76.657(4)°, β = 73.479(4)°, γ = 60.228(5)°, V = 12021.7(9) Å(3); 5, a = 20.0329(4) Å, b = 20.0601(4) Å, c = 34.3532(6) Å, α = 90.196(1)°, β = 91.344(2)°, γ = 119.370(2)°, V = 12025.8(4) Å(3). Differences in the number of DMSO molecules (coordinated and noncoordinated) and ligand (nitrate, DMSO) coordination modes are observed.

  10. Sexual excitement.

    PubMed

    Stoller, R J

    1976-08-01

    Sexual excitement depends on a scenario the person to be aroused has been writing since childhood. The story is an adventure, an autobiography disguised as fiction, in which the hero/heroine hides crucial intrapsychic conflicts, mysteries, screen memories of actual traumatic events and the resolution of these elements into a happy ending, best celebrated by orgasm. The function of the fantasy is to take these painful experiences and convert them to pleasure-triumph. In order to sharpen excitement-the vibration between the fear of original traumas repeating and the hope of a pleasurable conclusion this time-one introduces into the story elements of risk (approximations of the trauma) meant to prevent boredom and safety factors (sub-limnal signals to the storyteller that the risk are not truly dangerous). Sexual fantasy can be studied by means of a person's daydreams (including those chosen in magazines, books, plays, television, movies, and outright pornography), masturbatory behavior, object choice, foreplay, techniques of intercourse, or postcoital behavior.

  11. ADSORPTION-BISMUTH PHOSPHATE METHOD FOR SEPARATING PLUTONIUM

    DOEpatents

    Russell, E.R.; Adamson, A.W.; Boyd, G.E.

    1960-06-28

    A process is given for separating plutonium from uranium and fission products. Plutonium and uranium are adsorbed by a cation exchange resin, plutonium is eluted from the adsorbent, and then, after oxidation to the hexavalent state, the plutonium is contacted with a bismuth phosphate carrier precipitate.

  12. Discovery of the thallium, lead, bismuth, and polonium isotopes

    NASA Astrophysics Data System (ADS)

    Fry, C.; Thoennessen, M.

    2013-05-01

    Forty-two thallium, forty-two lead, forty-one bismuth, and forty-two polonium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  13. Compact, highly efficient ytterbium doped bismuthate glass waveguide laser.

    PubMed

    Mary, R; Beecher, S J; Brown, G; Thomson, R R; Jaque, D; Ohara, S; Kar, A K

    2012-05-15

    Laser slope efficiencies close to the quantum defect limit and in excess of 78% have been obtained from an ultrafast laser inscribed buried channel waveguide fabricated in a ytterbium-doped bismuthate glass. The simultaneous achievement of low propagation losses and preservation of the fluorescence properties of ytterbium ions is the basis of the outstanding laser performance.

  14. Controlled synthesis of bismuth oxyiodide toward optimization of photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Liao, Chenxing; Ma, Zhijun; Chen, Xiaofeng; He, Xin; Qiu, Jianrong

    2016-11-01

    A new investigation on the variation rule of the structure, morphology, chemical composition and photocatalytic performance of bismuth oxyiodide synthesized by solvothermal method as a function of reaction conditions was performed here. The composition and morphology of the product could be determined by X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The results revealed that the particle size together with content of iodide in bismuth oxyiodide decrease with the increase of the concentration of reaction precursors. Hollow Bi4O5I2 microsphere with specific surface area as high as 120.88 m2 g-1 can be easily synthesized when the concentration of the reaction precursors finally increased to 62.5 mM. Photocatalytic water purification performance of the as-prepared samples was evaluated by using Rhodamine B (RhB) as a model contaminant. The results revealed that the hollow Bi4O5I2 exhibited the best performance among all the bismuth oxyodide synthesized here for the degradation of RhB under visible light irradiation. Meanwhile, the formation mechanism of the hierarchical hollow structure of bismuth oxyiodide was investigated by the dissolution-recrystallization mechanism.

  15. REMOVAL OF CERTAIN FISSION PRODUCT METALS FROM LIQUID BISMUTH COMPOSITIONS

    DOEpatents

    Dwyer, O.E.; Howe, H.E.; Avrutik, E.R.

    1959-11-24

    A method is described for purifying a solution of urarium in liquid bismuth containing at least one metal from the group consisting of selenium, tellurium, palladium, ruthenium, rhodium, niobium, and zirconium. The solution is contacted with zinc in an inert atmosphere to form a homogeneous melt, a solid zinc phase is formed, and the zinc phase containing the metal is separated from the melt.

  16. Bismuth-based oxide semiconductors: Mild synthesis and practical applications

    NASA Astrophysics Data System (ADS)

    Timmaji, Hari Krishna

    In this dissertation study, bismuth based oxide semiconductors were prepared using 'mild' synthesis techniques---electrodeposition and solution combustion synthesis. Potential environmental remediation and solar energy applications of the prepared oxides were evaluated. Bismuth vanadate (BiVO4) was prepared by electrodeposition and solution combustion synthesis. A two step electrosynthesis strategy was developed and demonstrated for the first time. In the first step, a Bi film was first electrodeposited on a Pt substrate from an acidic BiCl3 medium. Then, this film was anodically stripped in a medium containing hydrolyzed vanadium precursor, to generate Bi3+, and subsequent BiVO4 formation by in situ precipitation. The photoelectrochemical data were consistent with the in situ formation of n-type semiconductor films. In the solution combustion synthesis procedure, BiVO4 powders were prepared using bismuth nitrate pentahydrate as the bismuth precursor and either vanadium chloride or vanadium oxysulfate as the vanadium precursor. Urea, glycine, or citric acid was used as the fuel. The effect of the vanadium precursor on the photocatalytic activity of combustion synthesized BiVO 4 was evaluated in this study. Methyl orange was used as a probe to test the photocatalytic attributes of the combustion synthesized (CS) samples, and benchmarked against a commercial bismuth vanadate sample. The CS samples showed superior activity to the commercial benchmark sample, and samples derived from vanadium chloride were superior to vanadium oxysulfate counterparts. The photoelectrochemical properties of the various CS samples were also studied and these samples were shown to be useful both for environmental photocatalytic remediation and water photooxidation applications. Silver bismuth tungstate (AgBiW2O8) nanoparticles were prepared for the first time by solution combustion synthesis by using silver nitrate, bismuth nitrate, sodium tungstate as precursors for Ag, Bi, and W

  17. In vitro antibacterial activity and cytocompatibility of bismuth doped micro-arc oxidized titanium.

    PubMed

    Lin, Dan-Jae; Tsai, Ming-Tzu; Shieh, Tzong-Ming; Huang, Heng-Li; Hsu, Jui-Ting; Ko, Yi-Chun; Fuh, Lih-Jyh

    2013-01-01

    Chemical manipulations of the implant surface produce a bactericidal feature to prevent infections around dental implants. Despite the successful use of bismuth against mucosal and dermis infections, the antibacterial effect of bismuth in the oral cavity remains under investigation. The aim of this study was to evaluate the antibacterial activities of bismuth compounds against Actinobacillus actinomycetemcomitans, Staphylococcus mutans, and methicillin-resistant Staphylococcus aureus (MRSA), and to investigate the antimicrobial effects of bismuth doped micro-arc oxidation (MAO) titanium via an agar diffusion test. Cell viability, alkaline phosphatase activity, and mineralization level of MG63 osteoblast-like cells seeded on the coatings were evaluated at 1, 7, and 14 days. The results demonstrate that bismuth nitrate possess superior antibacterial activity when compared with bismuth acetate, bismuth subgallate, and silver nitrate. The bismuth doped MAO coating (contained 6.2 atomic percentage bismuth) had good biological affinities to the MG63 cells and showed a higher antibacterial efficacy against Actinobacillus actinomycetemcomitans and MRSA, where the reduction rates of colony numbers is higher than that of the control group by 1.5 and 1.9 times, respectively. These in vitro evaluations demonstrate that titanium implants with bismuth on the surface may be useful for better infection control.

  18. Influence of Bi on the Er luminescence in yttrium-erbium disilicate thin films

    SciTech Connect

    Scarangella, Adriana; Miritello, Maria; Priolo, Francesco

    2014-09-28

    The influence of bismuth on erbium optical properties at 1.54 μm has been investigated in yttrium-erbium disilicate thin films synthesized by magnetron co-sputtering and implanted with two Bi different doses. The Bi depth distribution and the evolution of its oxidation states after annealing treatments at 1000 °C in two atmospheres, O₂ and N₂, have been investigated. It was found that only in O₂ the Bi³⁺ valence state is prevalent, thanks to the enhanced Bi mobility in the oxidizing ambient, as demonstrated by Rutherford backscattering spectrometry. At lower Bi content, although the formation of Bi⁰ metallic nanoparticles that are deleterious non radiative channels for Er luminescence, efficient energy transfer from Bi to Er has been obtained only in O₂. It is due to the excitation of ultraviolet broad Bi₃⁺ absorption band and the energy transfer to Er ions. We have evaluated that in this case, Er effective excitation cross section increased by a factor of 5 in respect with the one for direct Er absorption at 488 nm. At higher Bi dose, this mechanism is absent, but an increased Er optical efficiency at 1.54 μm has been observed under resonant excitation. It is due to the contribution of a fraction of Er ions having an increased lifetime. This phenomenon is associated with the formation of Bi agglomerates, induced at higher Bi doses, which well isolate Er from non-radiative quenching centers. The increased decay time assures higher optical efficiency at 1.54 μm.

  19. Bi4Si3O12 thin films for scintillator applications

    NASA Astrophysics Data System (ADS)

    Rincón-López, J. A.; Fernández-Benavides, D. A.; Giraldo-Betancur, A. L.; Cruz-Muñoz, B.; Riascos, H.; Muñoz-Saldaña, J.

    2016-04-01

    Bismuth silicate Bi4Si3O12 or BSO thin films were synthesized by pulsed laser deposition and a subsequent annealing treatment from a Bi-Fe-O and compared with films obtained with a pure Bi2O3 target. Bi-Fe-O amorphous thin films of different thicknesses were deposited on silicon substrates at room temperature and subsequently heat treated at 800 °C at different times to study the phase transformations, keeping in all steps a constant oxygen atmosphere. After annealing, Bi-Si-O crystalline phases are formed in all cases with different synthesis kinetics. The Bi-Fe-O target clearly increases the synthesis kinetic of a textured BSO phase having a dissociation and precipitation of homogeneously distributed Fe2O3 particles in the BSO matrix. The key aspects to obtain the Bi4Si3O12 stoichiometric phase are both the film thickness and the heat treatment time to allow the reaction between the Bi2O3 from the target and the SiO2 obtained after the oxidation of the substrate. A deposition time of Bi-Fe-O for 120 and 30 min annealing fulfills the conditions to obtain the Bi4Si3O12 stoichiometric composition and thus scintillation performance. The scintillation properties were measured by a fluorescence spectrophotometry. The stoichiometric Bi4Si3O12 samples show that under 260 nm excitation the material exhibits a peak emission at 466.6 nm. These Bi4Si3O12 thin films crystallize in eulytite phase with cubic structure (a = b = c = 10.291 Å). The phase content was obtained by Rietveld analysis of X-ray diffraction patterns.

  20. Highly spatially resolved structural and optical investigation of Bi nanoparticles in Y-Er disilicate thin films

    NASA Astrophysics Data System (ADS)

    Scarangella, A.; Amiard, G.; Reitano, R.; Priolo, F.; Boninelli, S.; Miritello, M.

    2016-08-01

    Er-containing silicon compatible materials have been widely used as infrared emitters for microphotonics application. In this field, the additional introduction of a proper sensitizer permits to increase the Er excitation cross sections, thus increasing its optical efficiency. This work aims to investigate the influence of a post-transition metal, bismuth, on the optical properties of erbium-yttrium disilicate thin films synthesized by magnetron co-sputtering. After thermal treatments at 1000 °C in O2 or N2 environment, the presence of small precipitates, about 6 nm in diameter, was evidenced by transmission electron microscopy analyses. The spatially resolved chemical nature of the nanoparticles was discerned in the Si and O rich environments by means of scanning transmission electron microscopy-energy dispersive X-ray and scanning transmission electron microscopy-electron energy loss spectroscopy analyses performed with nanometric resolution. In particular, metallic Bi nanoparticles were stabilized in the N2 environment, being strongly detrimental for the Er emission. A different scenario was instead observed in O2, where the formation of Bi silicate nanoparticles was demonstrated with the support of photoluminescence excitation spectroscopy. In particular, a broad band peaked at 255 nm, correlated to the excitation band of Bi silicate nanoparticles, was identified in Er excitation spectrum. Thus Bi silicate clusters act as sensitizer for Er ions, permitting to improve Er emission up to 250 times with respect to the resonant condition. Moreover, the Er decay time increases in the presence of the Bi silicate nanoparticles that act as cages for Er ions. These last results permit to further increase Er optical efficiency in the infrared range, suggesting (Bi + Er)-Y disilicate as a good candidate for applications in microphotonics.

  1. Effects of tripotassium dicitrato bismuthate (TDB) tablets or cimetidine in the treatment of duodenal ulcer.

    PubMed

    Hamilton, I; Worsley, B W; O'Connor, H J; Axon, A T

    1983-12-01

    Forty patients with duodenal ulcer were randomly allocated to treatment with either tripotassium dicitrato bismuthate tablets or cimetidine for six weeks. Endoscopically confirmed healing of the ulcer occurred in 80% treated with tripotassium dicitrato bismuthate tablets and in 85% treated with cimetidine. Symptomatic improvement was also similar in the two groups. Treatment with cimetidine was associated with an increase in pH of gastric aspirate during treatment and increased numbers of bacteria were isolated from the gastric aspirate during treatment, while the pH and bacterial flora of gastric aspirate did not change during tripotassium dicitrato bismuthate treatment. Serum and urinary bismuth levels rose during treatment with tripotassium dicitrato bismuthate and urinary excretion remained raised two weeks after cessation of treatment. Tripotassium dicitrato bismuthate tablets appear to be as effective as cimetidine in the treatment of duodenal ulcer without the potentially undesirable effects of a reduction in gastric acid secretion.

  2. Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure.

    PubMed

    Prakash, Om; Kumar, Anil; Thamizhavel, A; Ramakrishnan, S

    2017-01-06

    At ambient pressure, bulk rhombohedral bismuth is a semimetal that remains in the normal state down to at least 10 millikelvin. Superconductivity in bulk bismuth is thought to be unlikely because of the extremely low carrier density. We observed bulk superconductivity in pure bismuth single crystals below 0.53 millikelvin at ambient pressure, with an estimated critical magnetic field of 5.2 microteslas at 0 kelvin. Superconductivity in bismuth cannot be explained by the conventional Bardeen-Cooper-Schrieffer theory because its adiabatic approximation does not hold true for bismuth. Future theoretical work will be needed to understand superconductivity in the nonadiabatic limit in systems with low carrier densities and unusual band structures, such as bismuth.

  3. Fast pulsed excitation wiggler or undulator

    DOEpatents

    van Steenbergen, Arie

    1990-01-01

    A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

  4. Dielectric spectra of bismuth vanadate Bi4V2O11

    NASA Astrophysics Data System (ADS)

    Borisov, V. N.; Pashkov, V. M.; Poplavko, Iu. M.; Avakian, P. B.; Osipian, V. G.

    1990-06-01

    Results of a study of the temperature-frequency dependence of the behavior of the dielectric parameters of bismuth vanadate, Bi4V2O11, in the frequency range 1-100 GHz are reported. It is shown that bismuth vanadate is characterized by a large number of phase transitions. Yet another, previously unknown, phase transition in bismuth vanadate, masked by a relaxation process, has been observed in the temperature range 410-420 K.

  5. Near-IR luminescence from subvalent bismuth species in fluoride glass

    NASA Astrophysics Data System (ADS)

    Romanov, Alexey N.; Haula, Elena V.; Fattakhova, Zukhra T.; Veber, Alexander A.; Tsvetkov, Vladimir B.; Zhigunov, Denis M.; Korchak, Vladimir N.; Sulimov, Vladimir B.

    2011-11-01

    The broadband NIR luminescence of subvalent bismuth species was demonstrated in partially reduced ZrF 4-BiF 3-NaF and ZrF 4-BiF 3-BaF 2 fluoride glasses. The parameters of luminescence were reported and compared with luminescence from other bismuth-doped materials. Since fluoride glass compositions are based on strong Lewis acids (ZrF 4 in present case) they can stabilize NIR photoluminescent subvalent bismuth species.

  6. METHOD OF PREPARING URANIUM, THORIUM, OR PLUTONIUM OXIDES IN LIQUID BISMUTH

    DOEpatents

    Davidson, J.K.; Robb, W.L.; Salmon, O.N.

    1960-11-22

    A method is given for forming compositions, as well as the compositions themselves, employing uranium hydride in a liquid bismuth composition to increase the solubility of uranium, plutonium and thorium oxides in the liquid bismuth. The finely divided oxide of uranium, plutonium. or thorium is mixed with the liquid bismuth and uranium hydride, the hydride being present in an amount equal to about 3 at. %, heated to about 5OO deg C, agitated and thereafter cooled and excess resultant hydrogen removed therefrom.

  7. Bismuth(III) deferiprone effectively inhibits growth of Desulfovibrio desulfuricans ATCC 27774.

    PubMed

    Barton, Larry L; Lyle, Daniel A; Ritz, Nathaniel L; Granat, Alex S; Khurshid, Ali N; Kherbik, Nada; Hider, Robert; Lin, Henry C

    2016-04-01

    Sulfate-reducing bacteria have been implicated in inflammatory bowel diseases and ulcerative colitis in humans and there is an interest in inhibiting the growth of these sulfide-producing bacteria. This research explores the use of several chelators of bismuth to determine the most effective chelator to inhibit the growth of sulfate-reducing bacteria. For our studies, Desulfovibrio desulfuricans ATCC 27774 was grown with nitrate as the electron acceptor and chelated bismuth compounds were added to test for inhibition of growth. Varying levels of inhibition were attributed to bismuth chelated with subsalicylate or citrate but the most effective inhibition of growth by D. desulfuricans was with bismuth chelated by deferiprone, 3-hydroxy-1,2-dimethyl-4(1H)-pyridone. Growth of D. desulfuricans was inhibited by 10 μM bismuth as deferiprone:bismuth with either nitrate or sulfate respiration. Our studies indicate deferiprone:bismuth has bacteriostatic activity on D. desulfuricans because the inhibition can be reversed following exposure to 1 mM bismuth for 1 h at 32 °C. We suggest that deferiprone is an appropriate chelator for bismuth to control growth of sulfate-reducing bacteria because deferiprone is relatively nontoxic to animals, including humans, and has been used for many years to bind Fe(III) in the treatment of β-thalassemia.

  8. Selective coating of gastric ulcer by tripotassium dicitrato bismuthate in the rat.

    PubMed

    Koo, J; Ho, J; Lam, S K; Wong, J; Ong, G B

    1982-05-01

    Controlled clinical trials have shown that tripotassium dicitrato bismuthate healed duodenal and gastric ulcers significantly better than placebo. One mechanism suggested is that it forms a protective coat at the ulcer base. We studied this coating action in rats with chronic gastric ulcers produced by a standardized technique for mucosal wounding at the fundoantral junction. Bismuth was identified by histochemical staining using Castel's reagent, the specificity of which was verified in vitro against 13 other metallic compounds and chemicals. Our results showed that tripotassium dicitrato bismuthate had a coating affinity for the ulcer base, but not for the adjacent normal mucosa. All rats treated with tripotassium dicitrato bismuthate 1, 2, 4, and 6 h previously, but not the control rats treated with water or those treated with four other bismuth compounds, manifested a layer of bismuth that coated the ulcer base. Light and electron microscopy of the tripotassium dicitrato bismuthate-treated ulcers--but not their controls-revealed an abundance of macrophages, which had ingested the bismuth. This unique bismuth coat may insulate the ulcer base from acid-pepsin digestion, while the influx of macrophages may expedite reparative processes.

  9. METHOD OF SEPARATING FISSION PRODUCTS FROM FUSED BISMUTH-CONTAINING URANIUM

    DOEpatents

    Wiswall, R.H.

    1958-06-24

    A process is described for removing metal selectively from liquid metal compositions. The method effects separation of flssion product metals selectively from dilute solution in fused bismuth, which contains uraniunn in solution without removal of more than 1% of the uranium. The process comprises contacting the fused bismuth with a fused salt composition consisting of sodium, potassium and lithium chlorides, adding to fused bismuth and molten salt a quantity of bismuth chloride which is stoichiometrically required to convert the flssion product metals to be removed to their chlorides which are more stable in the fused salt than in the molten metal and are, therefore, preferentially taken up in the fused salt phase.

  10. Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials

    NASA Astrophysics Data System (ADS)

    Cheng, Gang; Yang, Hanmin; Rong, Kaifeng; Lu, Zhong; Yu, Xianglin; Chen, Rong

    2010-08-01

    Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO) 2CO 3) is one of commonly used antibacterial agents against Helicobacter pylori ( H. pylori). Different (BiO) 2CO 3 nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO) 2CO 3 nanostructures. The possible formation mechanism of different (BiO) 2CO 3 nanostructures fabricated under different conditions was also discussed.

  11. Coexistence of multiple metastable polytypes in rhombohedral bismuth

    PubMed Central

    Shu, Yu; Hu, Wentao; Liu, Zhongyuan; Shen, Guoyin; Xu, Bo; Zhao, Zhisheng; He, Julong; Wang, Yanbin; Tian, Yongjun; Yu, Dongli

    2016-01-01

    Derivative structural polytypes coexisting with the rhombohedral A7 structure of elemental bismuth (Bi) have been discovered at ambient condition, based on microstructure analyses of pure Bi samples treated under high pressure and high temperature conditions. Three structures with atomic positions close to those of the A7 structure have been identified through first-principles calculations, showing these polytypes energetically comparable to the A7 structure under ambient condition. Simulated diffraction data are in excellent agreement with the experimental observations. We argue that previously reported some variations of physical properties (e.g., density, electrical conductivity, and magnetism) in bismuth could be due to the formation of these polytypes. The coexistence of metastable derivative structural polytypes may be a widely occurring phenomenon in other elemental materials. PMID:26883895

  12. Ac irreversibility line of bismuth-based high temperature superconductors

    SciTech Connect

    Mehdaoui, A.; Beille, J.; Berling, D.; Loegel, B.; Noudem, J.G.; Tournier, R.

    1997-09-01

    We discuss the magnetic properties of lead doped Bi-2223 bulk samples obtained through combined magnetic melt texturing and hot pressing (MMTHP). The ac complex susceptibility measurements are achieved over a broad ac field range (1 Oe{lt}h{sub ac}{lt}100 Oe) and show highly anisotropic properties. The intergranular coupling is improved in the direction perpendicular to the applied stress and magnetic field direction, and an intragranular loss peak is observed for the first time. A comparison is made with other bismuth-based compounds and it is shown that the MMTHP process shifts the ac irreversibility line (ac IL) toward higher fields. It is also shown that all the ac IL{close_quote}s for quasi 2D bismuth-based compounds show a nearly quadratic temperature dependence and deviate therefore strongly from the linear behavior observed in quasi 3D compounds and expected from a critical state model.{copyright} {ital 1997 Materials Research Society.}

  13. Tin-silver-bismuth solders for electronics assembly

    DOEpatents

    Vianco, P.T.; Rejent, J.A.

    1995-08-08

    A lead-free solder alloy is disclosed for electronic assemblies composed of a eutectic alloy of tin and silver with a bismuth addition, x, of 0bismuth added to the eutectic tin-silver alloy as determined by DSC analysis, 10 C/min. A preferred alloy composition is 91.84Sn-3.33Ag-4.83Bi (weight percent based on total alloy weight). 4 figs.

  14. Tin-silver-bismuth solders for electronics assembly

    DOEpatents

    Vianco, Paul T.; Rejent, Jerome A.

    1995-01-01

    A lead-free solder alloy for electronic assemblies composed of a eutectic alloy of tin and silver with a bismuth addition, x, of 0bismuth added to the eutectic tin-silver alloy as determined by DSC analysis, 10.degree. C./min. A preferred alloy composition is 91.84Sn-3.33Ag-4.83Bi (weight percent based on total alloy weight).

  15. Bismuth iron titanate pyrochlores: Thermostability, structure and properties

    SciTech Connect

    Piir, I.V.; Koroleva, M.S.; Ryabkov, Yu.I.; Korolev, D.A.; Chezhina, N.V.; Semenov, V.G.; Panchuk, V.V.

    2013-08-15

    Iron containing bismuth titanates with pyrochlore structure Bi{sub 1.6}Fe{sub x}Ti{sub 2}O{sub 7−δ}, where 0.08≤x≤0.4, were obtained by ceramic procedure. The results of bough pycnometric density of the pyrochlores and of X-ray powder diffraction structure refinement points to the preference for iron atoms to occupy the Bi{sup 3+}-sites. Electric and magnetic properties were studied for single phase pyrochlores based on bismuth titanates. The magnetic ordering was studied by the methods of Mössbauer spectroscopy and magnetic susceptibility. - Graphical abstract: The ideal crystal structure of pyrochlore A{sub 2}B{sub 2}O{sub 6}O' (A—Bi{sup 3+}, Fe{sup 3+}; B—Ti{sup 4+}, Fe{sup 3+}). Highlights: • Bismuth titanate pyrochlores stable over a wide temperature range were obtained. • The distribution of Fe{sup 3+} over various sites was determined. • The obtained systems were characterized by magnetic susceptibility, Mössbauer spectroscopy and conductivity.

  16. XPS study on silica bismuthate glasses and glass ceramics

    NASA Astrophysics Data System (ADS)

    Simon, V.; Todea, M.; Takács, A. F.; Neumann, M.; Simon, S.

    2007-01-01

    X-ray photoelectron spectroscopy (XPS) was used to evidence the effect of the Bi 2O 3 to SiO 2 ratio and of partial crystallisation on the electronic charge density around the atoms entering silica-bismuthate glasses of nominal composition 0.01Fe 2O 3ṡ0.99[ xSiO 2ṡ(100- x)Bi 2O 3] with 10≤x≤60 mol%. The core level spectra show significant composition dependent changes in binding energy, and the full width at half maximum of photoelectron peaks both of cations and of oxygen atoms. The analysis reveals changes in electron density correlated with the ionic and covalent character of the samples. The shift in binding energy suggests charge transfer from silicon and oxygen atoms to bismuth atoms. Contrary to the expected behaviour in conventional silicate oxide systems, the results indicate an increase of ionicity for silicon and of covalency for bismuth atoms. The same evolution of ionicity/covalency is observed after partial crystallisation.

  17. Subinhibitory bismuth-thiols reduce virulence of Pseudomonas aeruginosa.

    PubMed

    Wu, Chieh-Liang; Domenico, Philip; Hassett, Daniel J; Beveridge, Terry J; Hauser, Alan R; Kazzaz, Jeffrey A

    2002-06-01

    Pseudomonas aeruginosa is a common pathogen in mechanically ventilated patients and produces a wide array of virulence factors. Bismuth-thiols (BTs) are active in vitro against all bacterial lung pathogens, including P. aeruginosa. The objective of these studies was to examine the biochemical and morphologic effects of sublethal BT concentrations on P. aeruginosa and to evaluate virulence in cell culture. Bismuth-dimercaprol, at a fraction of the minimal inhibitory concentration, reduced alginate expression by 67% in P. aeruginosa, whereas subinhibitory bismuth-ethanedithiol (BisEDT) reduced alginate by 92% in P. syringae. BisEDT effects on lipopolysaccharide content and type III secreted cytoxins were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Subinhibitory BisEDT reduced cell-associated lipopolysaccharide, and inhibited processing of the secreted cytotoxic protein ExoU. BisEDT-induced outer membrane blebbing and aggregation of cytoplasmic material was noted in electron microscopy. Virulence of P. aeruginosa was assessed by adherence to epithelial cells and sensitivity to serum killing. BisEDT inhibited adherence of P. aeruginosa to 16HBE14o- cells by 28% and to a collagen matrix by 53%. BisEDT-treated bacteria were also 100-fold more sensitive to serum bactericidal activity. In summary, low BT concentrations affect P. aeruginosa in a variety of ways, the combination of which may help prevent or resolve respiratory tract infection.

  18. Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials

    SciTech Connect

    Cheng Gang; Yang Hanmin; Rong Kaifeng; Lu Zhong; Yu Xianglin; Chen Rong

    2010-08-15

    Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO){sub 2}CO{sub 3}) is one of commonly used antibacterial agents against Helicobacter pylori (H. pylori). Different (BiO){sub 2}CO{sub 3} nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO){sub 2}CO{sub 3} nanostructures. The possible formation mechanism of different (BiO){sub 2}CO{sub 3} nanostructures fabricated under different conditions was also discussed. - Graphical abstract: Different bismuth subcarbonate ((BiO){sub 2}CO{sub 3}) nanostructures were successfully synthesized by a simple solvothermal method. It was found that the solvents and precursors have an influence on the morphologies of (BiO){sub 2}CO{sub 3} nanostructures.

  19. Thermodynamic properties of lanthanide metals in liquid bismuth

    NASA Astrophysics Data System (ADS)

    Yamana, Hajimu; Sheng, Jiawei; Souda, Naohiko; Moriyama, Hirotake

    2001-04-01

    Thermodynamic quantities of La, Gd, Tb, and Dy in liquid bismuth were experimentally determined by electromotive force (EMF) measurement using a cell consisting of molten alkaline chloride and liquid bismuth. Excess Gibbs energy changes and activity coefficients were determined at varying concentrations and temperatures. Through their temperature dependence, corresponding enthalpy changes and entropy changes were determined. The excess enthalpy changes of La, Gd, Tb, and Dy in liquid bismuth in a temperature range from 850 to 1100 K were evaluated to be, -221.54±2.31, -202.25±1.80, -199.83±0.55, and -193.80±0.99 kJ/mol, respectively. The systematic variation of excess enthalpy change of lanthanides along the 4f-series was discussed. As a result, it was found that the excess enthalpy changes of La, Gd, Tb, Dy, and Er are likely to depend linearly on the 2/3 power of their metallic volume.

  20. Memory switching in bismuth-vanadate glasses

    NASA Astrophysics Data System (ADS)

    Ghosh, Aswini

    1988-09-01

    The electrical V-I characteristics of thin blown films of V2O5-Bi2O3 glasses with 95-70 mol % V2O5 were studied in the temperature range 200-400 K. It was observed that at lower fields, the bulk resistance controlled the current. At higher fields, all the glass compositions showed memory switching characteristics. The decrease in the threshold voltage and increase in the threshold current with the increase of V2O5 content in the glasses and also with increasing temperature were observed. The switching action was associated with a phase transition from a disordered glassy state to an ordered devitrified state due to self-heating. The ideal thermal model was shown to be applicable to the present glasses.

  1. Solvothermal synthesis and study of nonlinear optical properties of nanocrystalline thallium doped bismuth telluride

    SciTech Connect

    Molli, Muralikrishna; Parola, Sowmendran; Avinash Chunduri, L.A.; Aditha, Saikiran; Sai Muthukumar, V; Mimani Rattan, Tanu; Kamisetti, Venkataramaniah

    2012-05-15

    Nanocrystalline Bismuth telluride and thallium (4 mol %) doped Bismuth telluride were synthesized through hydrothermal method. The as-prepared products were characterized using Powder X-ray Diffraction, High Resolution Transmission Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, UV-Visible spectroscopy and Fourier Transform Infrared Spectroscopy. Powder XRD results revealed the crystalline nature of the obtained phases. HRTEM showed the particle-like morphology of the products. The decrease in the absorption coefficient due to thallium doping was observed in FTIR spectra. The intensity dependent nonlinear optical properties of nanocrystalline bismuth telluride and thallium doped bismuth telluride were studied using the Z-scan technique in open-aperture configuration. Bismuth telluride doped with thallium showed enhanced nonlinear optical response compared to pristine bismuth telluride and hence could be used as a potential candidate for optical power limiting applications. - Graphical Abstract: Nonlinear transmission (Z-scan) curves of nanocrystalline bismuth telluride ({Delta}) and thallium doped bismuth telluride ({open_square}). Thallium doped bismuth telluride showed enhanced nonlinear absorption compared to bismuth telluride. Inset: TEM micrograph of bismuth telluride nanocrystallites. Highlights: Black-Right-Pointing-Pointer Synthesis of Nanocrystalline Bi{sub 2}Te{sub 3} and Thallium doped Bi{sub 2}Te{sub 3} through solvothermal method. Black-Right-Pointing-Pointer Reduced absorption coefficient due to thallium doping found from IR spectroscopy. Black-Right-Pointing-Pointer Open-aperture Z-scan technique for nonlinear optical studies. Black-Right-Pointing-Pointer Two photon absorption based model for theoretical fitting of Z-scan data. Black-Right-Pointing-Pointer Enhanced nonlinear absorption in Thallium doped Bi{sub 2}Te{sub 3} - potential candidate for optical power limiting applications.

  2. Pr3+-sensitized Er3+-doped bismuthate glass for generating high inversion rates at 2.7 µm wavelength.

    PubMed

    Guo, Yanyan; Tian, Ying; Zhang, Liyan; Hu, Lili; Chen, Nan-Kuang; Zhang, Junjie

    2012-08-15

    With a 980 nm laser diode pumping, the 2.7 µm emission and energy transfer processes of Er3+/Pr3+ codoped germanium-gallium-bismuthate glasses have been investigated. For Er3+ (1 mol. %) and Pr3+ (1 mol. %) molar concentrations, an intense 2.7 µm emission was obtained based on the high excited-state absorption of Er3+ ions and energy transfer (ET) between Er3+ and Pr3+ ions codopant (ET). The intrinsic lifetime of Er3+:4I(13/2) level is quenched effectively (from 6.85 ms down to 0.24 ms) and the population inversions between Er3+:4I(11/2) and 4I(13/2) levels are enhanced to achieve a four-level energy system at 2.7 µm.

  3. Optical parameters and upconversion fluorescence in Tm3+/Yb3+-doped alkali-barium-bismuth-tellurite glasses.

    PubMed

    Lin, Hai; Liu, Ke; Lin, Lin; Hou, Yanyan; Yang, Dianlai; Ma, Tiecheng; Pun, Edwin Yun Bun; An, Qingda; Yu, Jiayou; Tanabe, Setsuhisa

    2006-11-01

    Tm(3+)/Yb(3+)-doped alkali-barium-bismuth-tellurite (LKBBT) glasses have been fabricated and characterized. Density, refractive index, optical absorption, absorption and emission cross-sections of Yb(3+), Judd-Ofelt parameters and spontaneous transition probabilities of Tm(3+) have been measured and calculated, respectively. Intense blue three-photon upconversion fluorescence and near-infrared two-photon upconversion fluorescence were investigated under the excitation of a 980 nm diode laser at room temperature. Wide infrared transmission window, high refractive index and strong blue three-photon upconversion emission of Tm(3+) indicate that Tm(3+)/Yb(3+) co-doped LKBBT glasses are promising upconversion optical and laser materials.

  4. Bismuth Propellant Feed System Development at NASA-MSFC

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.

    2007-01-01

    NASA-MSFC has been developing liquid metal propellant feed systems capable of delivering molten bismuth at a prescribed mass flow rate to the vaporizer of an electric thruster. The first such system was delivered to NASA-JPL as part of the Very High Isp Thruster with Anode Layer (VHITAL) program. In this system, the components pictured were placed in a vacuum chamber and heated while the control electronics were located outside the chamber. The system was successfully operated at JPL in conjunction with a propellant vaporizer, and data was obtained demonstrating a new liquid bismuth flow sensing technique developed at MSFC. The present effort is aimed at producing a feed-system for use in conjunction with a bismuth-fed Hall thruster developed by Busek Co. Developing this system is more ambitious, however, in that it is designed to self-contain all the control electronics inside the same vacuum chamber as an operating bismuth-fed thruster. Consequently, the entire system, including an on-board computer, DC-output power supplies, and a gas-pressurization electro-pneumatic regulator, must be designed to survive a vacuum environment and shielded to keep bismuth plasma from intruding on the electronics and causing a shortcircuit. In addition, the hot portions of the feed system must be thermally isolated from the electronics to avoid failure due to high heat loads. This is accomplished using a thermal protection system (TPS) consisting of multiple layers of aluminum foil. The only penetrations into the vacuum chamber are an electrically isolated (floating) 48 VDC line and a fiberoptic line. The 48 VDC provides power for operation of the power supplies and electronics co-located with the system in the vacuum chamber. The fiberoptic Ethernet connection is used to communicate user-input control commands to the on-board computer and transmit real-time data back to the external computer. The partially assembled second-generation system is shown. Before testing at Busek, a

  5. Optical properties of dy doped lead and bismuth borate glasses - effect of glass composition, metal and semiconducting nanoparticles

    NASA Astrophysics Data System (ADS)

    Ooi, Hio Giap

    The optical properties of Dy3+ ions in lead borate and bismuth borate glasses are studied as a function of glass composition with PbO content (29.5 to 69.5mol%) and Bi2O3 content (29.5 to 59.5 mol%). We also studied the effect of metal and semiconducting nanoparticles on the absorption and fluorescence emission of Dy3+ ions in both lead and bismuth borate glasses. The absorption coefficient at each wavelength is obtained from the optical absorption spectrum of a glass sample, and the number density of rare-earth (RE) ions is calculated from the measurement of the glass density. These two parameters are then used to calculate the oscillator strength of each transition using Judd-Ofelt theory. Using the oscillator strength for each transition, we obtained the intensity parameters which represent changes in the symmetry of the ligand field at the Dy 3+ site (due to structural group changes and changes in Dy-O covalency). Radiative transition probabilities, the radiative lifetime of the excited states and the branching ratios are then obtained from these intensity parameters. The fluorescence spectra, obtained using 355 nm and 458 nm laser excitation, are analyzed by determining the area ratio of yellow/blue (Y/B) peaks and the wavelength of the hypersensitive transition (HST). The compositional dependence and effect of nanoparticles on the stimulated emission cross-section (sigmap), are then evaluated using radiative transition probability, the refractive index of the host glass, effective fluorescence linewidth, and the position of the band. In all of the glass systems, it was found that the optical properties are strongly influenced by structural changes arising from compositional variation and size of nanoparticles. Dy 3+ transitions exhibit large sigmap suggesting the possible utilization of these materials in laser applications.

  6. 75 FR 14491 - Listing of Color Additives Exempt From Certification; Bismuth Citrate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-26

    ... level of bismuth citrate as a color additive in cosmetics intended for coloring hair on the scalp. This... citrate as a color additive in cosmetics intended for coloring hair on the scalp from 0.5 percent (weight... bismuth citrate in cosmetics intended for coloring scalp hair to 2.0 percent (w/v) with no changes to...

  7. Biosynthesis of bismuth nanoparticles using Serratia marcescens isolated from the Caspian Sea and their characterisation.

    PubMed

    Nazari, P; Faramarzi, M A; Sepehrizadeh, Z; Mofid, M R; Bazaz, R D; Shahverdi, A R

    2012-06-01

    Today, synthesis of nanoparticles (NPs) using micro-organisms has been receiving increasing attention. In this investigation, a bismuth-reducing bacterium was isolated from the Caspian Sea in Northern Iran and was used for intracellular biosynthesis of elemental bismuth NPs. This isolate was identified as non-pigmented Serratia marcescens using conventional identification assays and the 16s rDNA fragment amplification method and used to prepare bismuth NPs. The biogenic bismuth NPs were released by liquid nitrogen and highly purified using an n-octanol water two-phase extraction system. Different characterisations of the purified NPs such as particle shapes, size and purity were carried out with different instruments. The energy-dispersive X-ray and X-ray diffraction (XRD) patterns demonstrated that the purified NPs consisted of only bismuth and are amorphous. In addition, the transmission electron micrograph showed that the small NPs formed larger aggregated NPs around <150 nm. Although the chemical syntheses of elemental bismuth NPs have been reported in the literature, the biological synthesis of elemental bismuth NPs has not been published yet. This is the first report to demonstrate a biological method for synthesising bismuth NPs and their purification with a simple solvent partitioning method.

  8. Near-infrared photoluminescence and Raman characterization of bismuth-embedded sodalite nanocrystals.

    PubMed

    Sun, Hong-Tao; Fujii, Minoru; Sakka, Yoshio; Bai, Zhenhua; Shirahata, Naoto; Zhang, Liyan; Miwa, Yuji; Gao, Hong

    2010-06-01

    Ultrabroadband near-IR (NIR) emission has been realized in bismuth-embedded sodalite nanocrystals. Steady-state and time-resolved photoluminescence and Raman results suggest that Bi(+) active centers contribute to the NIR emission. This study demonstrates that sodalite nanocrystals can serve as excellent hosts for bismuth NIR active centers, thus paving the way for their wide applications in nanophotonics.

  9. Local Structural Distortion Induced Uniaxial Negative Thermal Expansion in Nanosized Semimetal Bismuth.

    PubMed

    Li, Qiang; Zhu, He; Zheng, Lirong; Fan, Longlong; Ren, Yang; Chen, Jun; Deng, Jinxia; Xing, Xianran

    2016-11-01

    The corrugated layer structure bismuth has been successfully tailored into negative thermal expansion along c axis by size effect. Pair distribution function and extended X-ray absorption fine structure are combined to reveal the local structural distortion for nanosized bismuth. The comprehensive method to identify the local structure of nanomaterials can benefit the regulating and controlling of thermal expansion in nanodivices.

  10. Experimental investigation of forced-convection heat-transfer characteristics of lead-bismuth eutectic

    NASA Technical Reports Server (NTRS)

    Lubarsky, Bernard

    1951-01-01

    The forced-convection heat-transfer characteristics of lead-bismuth eutectic were experimentally investigated. Experimental values of Nusselt number for lead-bismuth fell considerably below predicted values. The addition of a wetting agent did not change the heat transfer characteristics.

  11. Method of Creating Micro-scale Silver Telluride Grains Covered with Bismuth Nanoparticles

    NASA Technical Reports Server (NTRS)

    Kim, Hyun-Jung (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Park, Yeonjoon (Inventor); Lee, Kunik (Inventor)

    2014-01-01

    Provided is a method of enhancing thermoelectric performance by surrounding crystalline semiconductors with nanoparticles by contacting a bismuth telluride material with a silver salt under a substantially inert atmosphere and a temperature approximately near the silver salt decomposition temperature; and recovering a metallic bismuth decorated material comprising silver telluride crystal grains.

  12. Optical studies of Sm³⁺ ions doped zinc alumino bismuth borate glasses.

    PubMed

    Swapna, K; Mahamuda, Sk; Srinivasa Rao, A; Shakya, S; Sasikala, T; Haranath, D; Vijaya Prakash, G

    2014-05-05

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm(3+)) ions were prepared by using melt quenching technique and characterized for their lasing potentialities in visible region by using the techniques such as optical absorption, emission and emission decay measurements. Radiative properties for various fluorescent levels of Sm(3+) ions were estimated from absorption spectral information using Judd-Ofelt (JO) analysis. The emission spectra and con-focal photoluminescence images obtained by 410 nm laser excitation demonstrates very distinct and intense orange-red emission for all the doped glasses. The suitable concentration of Sm(3+) ions in these glasses to act as an efficient lasing material has been discussed by measuring the emission cross-section and branching ratios for the emission transitions. The quantum efficiencies were also been estimated from emission decay measurements recorded for the (4)G5/2 level of Sm(3+) ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm(3+) ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers.

  13. Optical absorption and fluorescence properties of Er3+/Yb3+ codoped lead bismuth alumina borate glasses

    NASA Astrophysics Data System (ADS)

    Goud, K. Krishna Murthy; Reddy, M. Chandra Shekhar; Rao, B. Appa

    2014-04-01

    Lead bismuth alumina borate glasses codoped with Er3+/Yb3+ were prepared by melt quenching technique. Optical absorption, FTIR and photoluminescence spectra of these glasses have been studied. Judd-Ofelt theory has been applied to to the f ↔ f transitions for evaluating Ω2, Ω4 and Ω6 parameters. Radiative properties like branching ratio βr and the radiative life time τR have been determined on the basis of Judd-Ofelt theory. Upconversion emissions have been observed under 980nm laser excitation at room temperature. Green and red up-conversion emissions are centered at 530, 550 and 656 nm corresponding to 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ respectively. The results obtained are discussed quantitatively based on the energy transfer between Yb3+ and Er3+.

  14. Low-temperature photochromic response of phosphorus-doped bismuth silicon oxide

    NASA Astrophysics Data System (ADS)

    McCullough, J. S.; Harmon, Angela; Martin, J. J.; Martin, J. J.; Harris, M. T.; Larkin, J. J.

    1995-08-01

    Phosphorus is one of several dopants that electronically compensate the native deep donor responsible for the yellow coloration observed in bismuth silicon oxide (BSO). Low-temperature optical absorption measurements of a series of Czochralski-grown P-doped BSO crystals show that ˜0.1-0.15 at. % P is needed in the sample to fully remove the yellow coloration. The absorption cutoff in the fully compensated P-doped sample was at 3.2 eV while compensated Al- and Ga-doped samples cutoff at 3.35 eV. Excitation at 10-15 K with near band-edge light produces photochromic absorption bands. In the lightly-doped (partially bleached) samples these bands were identical to those observed in undoped BSO. In the fully bleached sample a new spectrum was observed. Its major contribution was a band centered near 1.8 eV with a weaker absorption in the blue-green. By comparison with the spectra observed in undoped and in Al-doped material before and after photoexcitation it is believed that the 1.8 eV band is due to the [PO4]- center and that the broad 2.45 eV band observed in Al- and Ga-doped BSO is due to the [BiO4]0 center.

  15. Luminescence properties of Tm3+/Yb3+ codoped lead alumina bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Goud, K. Krishna Murthy; Reddy, M. Chandra Shekhar; Rao, B. Appa

    2016-05-01

    This paper reports on the spectroscopic properties of Yb3+ and Tm3+ codoped lead alumina bismuth borate glasses. Optical absorption spectra of these Samples were recorded at room temperature in the wavelength range 350-2000 nm. The absorption spectra exhibited the bands at 658 nm (3H6→3F2), 686 nm (3H6→3F3), 792 nm (3H6→3H4), 1211 nm (3H6→3H5) and 1663 nm (3H6→3F4) due to Tm3+ ions. The band at 977 nm (2F7/2→2F5/2) is due to Yb3+ ions. Optical band gap (Eopt) and Urbach energy (ΔE) values were calculated from the spectra. It was observed that the value of optical band gap decreases with increase in the concentration of Tm3+ ions. The upconversion luminescence spectra were measured under excitation of 980 nm laser diode, and the intense blue (470 nm) and green (656 nm) emission were simultaneously observed at room temperature. A proposed upconversion mechanism involving energy transfer from Yb3+ to Tm3+ has been presented.

  16. Optical properties of bismuth-doped silica fibres in the temperature range 300 - 1500 K

    SciTech Connect

    Dvoretskii, D A; Bufetov, Igor' A; Vel'miskin, V V; Zlenko, Alexander S; Khopin, V F; Semjonov, S L; Guryanov, Aleksei N; Denisov, L K; Dianov, Evgenii M

    2012-09-30

    The visible and near-IR absorption and luminescence bands of bismuth-doped silica and germanosilicate fibres have been measured for the first time as a function of temperature. The temperature-dependent IR luminescence lifetime of a bismuth-related active centre associated with silicon in the germanosilicate fibre has been determined. The Bi{sup 3+} profile across the silica fibre preform is shown to differ markedly from the distribution of IR-emitting bismuth centres associated with silicon. The present results strongly suggest that the IR-emitting bismuth centre comprises a lowvalence bismuth ion and an oxygen-deficient glass network defect. (optical fibres, lasers and amplifiers. properties and applications)

  17. Bismuth-induced phase control of GaAs nanowires grown by molecular beam epitaxy

    SciTech Connect

    Lu, Zhenyu; Chen, Pingping E-mail: luwei@mail.sitp.ac.cn; Shi, Suixing; Yao, Luchi; Zhou, Xiaohao; Lu, Wei E-mail: luwei@mail.sitp.ac.cn; Zhang, Zhi; Zhou, Chen; Zou, Jin

    2014-10-20

    In this work, the crystal structure of GaAs nanowires grown by molecular beam epitaxy has been tailored only by bismuth without changing the growth temperature and V/III flux ratio. The introduction of bismuth can lead to the formation of zinc-blende GaAs nanowires, while the removal of bismuth changes the structure into a 4H polytypism before it turns back to the wurtzite phase eventually. The theoretical calculation shows that it is the steadiest for bismuth to adsorb on the GaAs(111){sub B} surface compared to the liquid gold catalyst surface and the interface between the gold catalyst droplet and the nanowire, and these adsorbed bismuth could decrease the diffusion length of adsorbed Ga and hence the supersaturation of Ga in the gold catalyst droplet.

  18. Bismuth doping effect on crystal structure and photodegradation activity of Bi-TiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Chung; Chang, Yin-Hsuan; Lin, Ting-Han

    2017-04-01

    The bismuth precursor is adopted as dopant to synthesize bismuth doped titanium dioxide nanoparticles (Bi-TiO2 NPs) with sol-gel method following by the thermal annealing treatment. We systematically developed a series of Bi-TiO2 NPs at several calcination temperatures and discovered the corresponding crystal structure by varying the bismuth doping concentration. At a certain 650 °C calcination temperature, the crystal structure of bismuth titanate (Bi2Ti2O7) is formed when the bismuth doping concentration is as high as 10.0 mol %. The photocatalytic activity of Bi-TiO2 NPs is increased by varying the doping concentration at the particular calcination temperature. By the definition X-ray diffraction (XRD) structural identification, a phase diagram of Bi-TiO2 NPs in doping concentration versus calcination temperature is provided. It can be useful for further study in the crystal structure engineering and the development of photocatalyst.

  19. Determination of nanogram amounts of bismuth in rocks by substoichiometric isotope dilution analysis

    USGS Publications Warehouse

    Greenland, L. Paul; Campbell, E.Y.

    1972-01-01

    A rapid procedure suitable for the routine determination of 1-10 ng of bismuth in a silicate rock matrix is described. Results for the U.S. Geological Survey standard rocks are presented. Rocks and minerals are dissolved in hydrofluoric-perchloric acid in the presence of 207Bi tracer and the silica is removed by evaporation. The perchloric acid residue is taken up in water and bismuth iodide is extracted into methyl isobutyl ketone. After three acid-iodide washes, the bismuth is stripped into water and reacted with a substoichiometric amount of EDTA. Excess of bismuth is extracted as the iodide and the specific activity of the bismuth-EDTA complex is determined. ?? 1972.

  20. Nanotextured pillars of electrosprayed bismuth vanadate for efficient photoelectrochemical water splitting.

    PubMed

    Yoon, Hyun; Mali, Mukund G; Choi, Jae Young; Kim, Min-woo; Choi, Sung Kyu; Park, Hyunwoong; Al-Deyab, Salem S; Swihart, Mark T; Yarin, Alexander L; Yoon, Sam S

    2015-03-31

    We demonstrate, for the first time, electrostatically sprayed bismuth vanadate (BiVO4) thin films for photoelectrochemical water splitting. Characterization of these films by X-ray diffraction, Raman scattering, and high-resolution scanning electron microscopy analyses revealed the formation of nanotextured pillar-like structures of highly photoactive monoclinic scheelite BiVO4. Electrosprayed BiVO4 nanostructured films yielded a photocurrent density of 1.30 and 1.95 mA/cm(2) for water and sulfite oxidation, respectively, under 100 mW/cm(2) illumination. The optimal film thickness was 3 μm, with an optimal postannealing temperature of 550 °C. The enhanced photocurrent is facilitated by formation of pillar-like structures in the deposit. We show through modeling that these structures result from the electrically-driven motion of submicron particles in the direction parallel to the substrate, as they approach the substrate, along with Brownian diffusion. At the same time, opposing thermophoretic forces slow their approach to the surface. The model of these processes proposed here is in good agreement with the experimental observations.

  1. Epitaxial Growth and Characterization of Iron Chalcogenide/Bismuth Chalcogenide Heterostructures

    NASA Astrophysics Data System (ADS)

    Flanagan, Thomas; Kandala, Abhinav; Lee, Joon Sue; Kempinger, Susan E.; Richardella, Anthony; Samarth, Nitin

    Heterostructures consisting of topological insulators (TIs) interfaced with superconductors and with ferromagnets have been predicted to give rise to phenomena of both fundamental and applied interest. With superconductors, the region of proximity-induced superconductivity should have px + ipy symmetry, and vortices in this region have been predicted to host Majorana modes, which may be useful as quantum bits. With ferromagnets, such phenomena as the topological magnetoelectric effect have been predicted. Iron chalcogenides, such as iron selenide and iron telluride, are ideal candidates for combining with TIs, since, with only minor changes to growth conditions, they can be superconducting, ferromagnetic, or antiferromagnetic. We describe the growth and characterization of heterostructures that combine thin films of the iron and bismuth chalcogenides, focusing on low temperature magnetoresistance measurements. Our measurements reveal a transient hysteretic magnetoresistance with surprisingly long relaxation times (minutes). This phenomenon appears to be a generic characteristic of all heterostructures that interface TIs with magnetic spins, albeit with structure-specific relaxation times. We discuss possible origins of this unusual phenomenon. Funded by ARO/MURI.

  2. Piezoelectric thick bismuth titanate/lead zirconate titanate composite film transducers for smart NDE of metals

    NASA Astrophysics Data System (ADS)

    Kobayashi, M.; Jen, C.-K.

    2004-08-01

    Thick film piezoelectric ceramic sensors have been successfully deposited on different metallic substrates with different shapes by a sol-gel spray technique. The ball-milled bismuth titanate fine powders were dispersed into PZT solution to achieve the gel. The films with desired thickness up to 200 µm have been obtained through the multilayer coating approach. These thick films were also effectively coated onto thin sheet metals of thickness down to 25 µm. Self-support films with flat and shell geometries were made. Piezoelectricity was achieved using the corona discharge poling method. The area of the top silver paste electrode was also optimized. The center frequencies of ultrasonic signals generated by these films ranged from 3.6 to 30 MHz and their bandwidth was broad as well. The ultrasonic signals generated and received by these ultrasonic transducers (UTs) operated in the pulse/echo mode had a signal to noise ratio more than 30 dB. The main advantages of such sensors are that they (1) do not need couplant, (2) can serve as piezoelectric and UT, (3) can be coated onto curved surfaces and (4) can operate up to 440 °C. The capability of these thick film UTs for non-destructive evaluation of materials at 440 °C has been demonstrated.

  3. Thermal transport in bismuth telluride quintuple layer: mode-resolved phonon properties and substrate effects

    PubMed Central

    Shao, Cheng; Bao, Hua

    2016-01-01

    The successful exfoliation of atomically-thin bismuth telluride (Bi2Te3) quintuple layer (QL) attracts tremendous research interest in this strongly anharmonic quasi-two-dimensional material. The thermal transport properties of this material are not well understood, especially the mode-wise properties and when it is coupled with a substrate. In this work, we have performed molecular dynamics simulations and normal mode analysis to study the mode-resolved thermal transport in freestanding and supported Bi2Te3 QL. The detailed mode-wise phonon properties are calculated and the accumulated thermal conductivities with respect to phonon mean free path (MFP) are constructed. It is shown that 60% of the thermal transport is contributed by phonons with MFP longer than 20 nm. Coupling with a-SiO2 substrate leads to about 60% reduction of thermal conductivity. Through varying the interfacial coupling strength and the atomic mass of substrate, we also find that phonon in Bi2Te3 QL is more strongly scattered by interfacial potential and its transport process is less affected by the dynamics of substrate. Our study provides an in-depth understanding of heat transport in Bi2Te3 QL and is helpful in further tailoring its thermal property through nanostructuring. PMID:27263656

  4. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  5. Cytotoxic Effect of Lipophilic Bismuth Dimercaptopropanol Nanoparticles on Epithelial Cells.

    PubMed

    Rene, Hernandez-Delgadillo; Badireddy, Appala Raju; José, Martínez-Sanmiguel Juan; Francisco, Contreras-Cordero Juan; Israel, Martinez-Gonzalez Gustavo; Isela, Sánchez-Nájera Rosa; Chellam, Shankararaman; Claudio, Cabral-Romero

    2016-01-01

    Bismuth nanoparticles have many interesting properties to be applied in biomedical and medicinal sectors, however their safety in humans have not been comprehensively investigated. The objective of this research was to determine the cytotoxic effect of bismuth dimercaptopropanol nanoparticles (BisBAL NPs) on epithelial cells. The nanoparticles are composed of 18.7 nm crystallites on average and have a rhombohedral structure, agglomerating into chains-like or clusters of small nanoparticles. Based on MTT viability assay and fluorescence microscopy, cytotoxicity was not observed on monkey kidney cells after growing with 5 µM of BisBAL NPs for 24 h. Employing same techniques, identical results were obtained with human epithelial cells (HeLa), showing a not strain-dependent phenomenon. The absence of toxic effects on epithelial cells growing with BisBAL NPs was corroborated with long-time experiments (24-72 hrs.), showing no difference in comparison with growing control (cells without nanoparticles). Further, genotoxicity assays, comet assay and fluorescent microscopy and electrophoresis in bromide-stained agarose gel revealed no damage to genomic DNA of MA104 cells after 24 h. of exposition to BisBAL NPs. Finally, the effect of bismuth nanoparticles on protein synthesis was studied in cells growing with BisBAL NPs for 24 h. SDS-PAGE assays showed no difference between treated and untreated cells, suggesting that BisBAL NPs did not interfere with protein synthesis. Hence BisBAL NPs do not appear to exert cytotoxic effects suggesting their biological compatibility with epithelial cells.

  6. Conduction mechanism in bismuth silicate glasses containing titanium

    NASA Astrophysics Data System (ADS)

    Dult, Meenakshi; Kundu, R. S.; Murugavel, S.; Punia, R.; Kishore, N.

    2014-11-01

    Bismuth silicate glasses mixed with different concentrations of titanium dioxide having compositions xTiO2-(60-x)Bi2O3-40SiO2 with x=0, 5, 10, 15 and 20 were prepared by the normal melt quench technique. The frequency dependence of the ac electrical conductivity of different compositions of titanium bismuth silicate glasses has been studied in the frequency range 10-1 Hz to 10 MHz and in the temperature range 623-703 K. The temperature and frequency dependent conductivity is found to obey Jonscher's universal power law for all the compositions of titanium bismuth silicate glass system. The dc conductivity (σdc), so called crossover frequency (ωH), and frequency exponent (s) have been estimated from the fitting of experimental data of ac conductivity with Jonscher's universal power law. Enthalpy to dissociate the cation from its original site next to a charge compensating center (Hf) and enthalpy of migration (Hm) have also been estimated. The conductivity data have been analyzed in terms of different theoretical models to determine the possible conduction mechanism. Analysis of the conductivity data and the frequency exponent shows that the correlated barrier hopping of electrons between Ti3+ and Ti4+ ions in the glasses is the most favorable mechanism for ac conduction. The temperature dependent dc conductivity has been analyzed in the framework of theoretical variable range hopping model (VRH) proposed by Mott which describe the hopping conduction in disordered semiconducting systems. The various polaron hopping parameters have also been deduced. Mott's VRH model is found to be in good agreement with experimental data and the values of inverse localization length of s-like wave function (α) obtained by this model with modifications suggested by Punia et al. are close to the ones reported for a number of oxide glasses.

  7. Modeling astatine production in liquid lead-bismuth spallation targets

    NASA Astrophysics Data System (ADS)

    David, J. C.; Boudard, A.; Cugnon, J.; Ghali, S.; Leray, S.; Mancusi, D.; Zanini, L.

    2013-03-01

    Astatine isotopes can be produced in liquid lead-bismuth eutectic targets through proton-induced double charge exchange reactions on bismuth or in secondary helium-induced interactions. Models implemented into the most common high-energy transport codes generally have difficulties to correctly estimate their production yields as was shown recently by the ISOLDE Collaboration, which measured release rates from a lead-bismuth target irradiated by 1.4 and 1 GeV protons. In this paper, we first study the capability of the new version of the Liège intranuclear cascade model, INCL4.6, coupled to the deexcitation code ABLA07 to predict the different elementary reactions involved in the production of such isotopes through a detailed comparison of the model with the available experimental data from the literature. Although a few remaining deficiencies are identified, very satisfactory results are found, thanks in particular to improvements brought recently on the treatment of low-energy helium-induced reactions. The implementation of the models into MCNPX allows identifying the respective contributions of the different possible reaction channels in the ISOLDE case. Finally, the full simulation of the ISOLDE experiment is performed, taking into account the likely rather long diffusion time from the target, and compared with the measured diffusion rates for the different astatine isotopes, at the two studied energies, 1.4 and 1 GeV. The shape of the isotopic distribution is perfectly reproduced as well as the absolute release rates, assuming in the calculation a diffusion time between 5 and 10hours. This work finally shows that our model, thanks to the attention paid to the emission of high-energy clusters and to low-energy cluster induced reactions, can be safely used within MCNPX to predict isotopes with a charge larger than that of the target by two units in spallation targets, and, probably, more generally to isotopes created in secondary reactions induced by composite

  8. Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

    NASA Astrophysics Data System (ADS)

    Rahman, Airul Azha Abd; Umar, Akrajas Ali; Chen, Xiaomei; Salleh, Muhamad Mat; Oyama, Munetaka

    2016-02-01

    The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m-1 K-2) and 10 μV/K (and 19.5 μW m-1 K-2), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output load as high as 50

  9. Fano interference at the excitation of coherent phonons: Relation between the asymmetry parameter and the initial phase of coherent oscillations

    SciTech Connect

    Misochko, O. V. Lebedev, M. V.

    2015-04-15

    The theoretical assertion that the Fano asymmetry parameter and the asymptotic initial phase of a harmonic oscillator interacting with a continuum are interrelated is experimentally verified. By an example of coherent fully symmetric A{sub 1g} phonons in bismuth that are excited by ultrashort laser pulses at liquid helium temperature, it is demonstrated that, for negative values of the asymmetry parameter, the asymptotic phase increases as the modulus of the parameter decreases.

  10. Solvothermal synthesis of uniform bismuth nanospheres using poly(N-vinyl-2-pyrrolidone) as a reducing agent

    PubMed Central

    2011-01-01

    Uniform bismuth nanospheres were successfully prepared from bismuth nitrate in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) by solvothermal process. The product was characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray. PVP plays a critical role both as a reducing agent and a capping agent in the formation of bismuth nanospheres. Shape and size of bismuth nanospheres could be tuned by changing the employed PVP/bismuth salt ratio. It was also found the solvent had an effect on the morphologies of bismuth nanomaterials. The possible formation and growth mechanism of bismuth nanospheres were also discussed and proposed to explain the reduction step. PMID:21711606

  11. Surface characteristics of two-component thallium-bismuth melts

    NASA Astrophysics Data System (ADS)

    Ashkhotov, O. G.; Ashkhotova, I. B.; Aleroev, M. A.; Bliev, A. P.; Magkoev, T. T.

    2017-02-01

    The surface tension of pure Tl and Bi, and two-component alloys of them over the range of volume concentrations and temperatures starting from the liquidus temperature up to 623 K are measured by the lying-drop method with strong control over the surface condition by means of Auger electron spectroscopy. The results from in situ measurements of the surface tensions of Tl and Bi with surfactant impurities, and for atomically pure surfaces and Tl-Bi solutions, are given. It is shown that surfaces are enriched by bismuth, the concentration of which grows along with temperature.

  12. Bismuth germanate as a potential scintillation detector in positron cameras.

    PubMed

    Cho, Z H; Farukhi, M R

    1977-08-01

    Timing and energy resolutions of the bismuth germanate (Bi4Ge3O12) scintillation crystals were studied, with particular respect to a positron-camera application. In comparison with the NaI(Tl) system, the detection efficiency for annihilation radiation is more than triple, and coincidence detection efficiency is more than ten times as good. This paper explores the properties of the new scintillator material and their bearing on the spatial resolution and the efficiency of coincidence detection in positron cameras with stationary ring detectors.

  13. Gastric ulcer healing with tripotassium dicitrato bismuthate and subsequent relapse.

    PubMed

    Sutton, D R

    1982-07-01

    Fifty patients with endoscopically proven gastric ulcers completed a one month double-blind randomised trial of tripotassium dicitrato bismuthate (TBD) (DeNol) compared with an identical placebo. Ulcer healing occurred in 18 (72%) of the 25 patients given TDB and in nine (36%) of the patients given placebo. The TDB group experienced significantly less pain than the placebo group. During a follow-up of 29 patients with healed ulcers for up to 44 months, relapse occurred in 13 (45%). It was highest in the first three months (27%) and had risen to 41% at two years.

  14. Relaxation dynamics of lithium ions in lead bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Pan, A.; Ghosh, A.

    2000-08-01

    We have investigated relaxation dynamics of lithium ions in lead bismuthate glasses in the frequency range from 10 Hz to 2 MHz and in the temperature range from 303-553 K. Using the Anderson-Stuart model, we have calculated the activation energy, which is observed to be lower than that of the dc conductivity. We have studied the relaxation mechanism of these glasses in the framework of the electric modulus and conductivity formalisms. The microscopic parameters obtained from these formalisms have been compared. We have also calculated the decoupling index and correlated them with the stretched exponential relaxation parameter and the dc conductivity.

  15. Potentiometric determination of plutonium by sodium bismuthate oxidation.

    PubMed

    Charyulu, M M; Rao, V K; Natarajan, P R

    1984-12-01

    A potentiometric method for the determination of plutonium is described, in which the plutonium is quantitatively oxidized to plutonium(VI) with sodium bismuthate in nitric acid medium, the excess of oxidant is destroyed chemically and plutonium(VI) is reduced to plutonium(IV) with a measured excess of iron(II), the surplus of which is back-titrated with dichromate. For 3-5 mg of plutonium the error is less than 0.2%. For submilligram quantities of plutonium in presence of macro-amounts of uranium the error is below 2.0%.

  16. Kinetics of Propagating Phase Transformation in Compressed Bismuth

    SciTech Connect

    Bastea, M; Bastea, S; Emig, J; Springer, P; Reisman, D

    2004-08-18

    The authors observed dynamically driven phase transitions in isentropically compressed bismuth. By changing the stress loading conditions they explored two distinct cases one in which the experimental signature of the phase transformation corresponds to phase-boundary crossings initiated at both sample interfaces, and another in which the experimental trace is due to a single advancing transformation front in the bulk of the material. They introduce a coupled kinetics-hydrodynamics model that for this second case enables them, under suitable simplifying assumptions, to directly extract characteristic transition times from the experimental measurements.

  17. Dielectric behavior of barium modified strontium bismuth titanate ceramic

    NASA Astrophysics Data System (ADS)

    Nayak, P.; Badapanda, T.; Anwar, S.; Panigrahi, S.

    2014-04-01

    Barium Modified Strontium Bismuth Titanate(SBT) ceramic with general formula Sr1-xBaxBi4Ti4O15 is prepared by solid state reaction route. The structural analysis of the ceramics was done by X-ray diffraction technique. The X-ray patterns show that all the compositions are of single phase with orthorhombic structure. The temperature dependent dielectric behavior shows that the transition temperature decreases with Ba content but the maximum dielectric constant increases. The decreases of the transition with increase in Ba2+ ion, may be due to the decrease of orthorhombicity by the incorporation of Ba2+ ion in SBT lattice.

  18. Solution combustion synthesis and characterization of nanosized bismuth ferrite

    NASA Astrophysics Data System (ADS)

    Sai Kumar, V. Sesha; Rao, K. Venkateswara; Krishnaveni, T.; Kishore Goud, A. Shiva; Reddy, P. Ranjith

    2012-06-01

    The present paper describes a simple method of nanosized BiFeO3 by the solution combustion synthesis using bismuth and iron nitrates as oxidizers and the combination fuel of citric acid and ammonium hydroxide, with fuel to oxidizer ratio (Ψ = 1) one. The X-ray Diffraction results indicated rhombohedral phase (R3m) with JCPDS data card no: 72-2035. The ferroelectric transition of the sample at 8310C was detected by differential thermal analysis. Thermal analysis was done by Thermal gravimetric-Differential thermal analyzer and obtained results were presented in this paper.

  19. Bismuth oxide aqueous colloidal nanoparticles inhibit Candida albicans growth and biofilm formation.

    PubMed

    Hernandez-Delgadillo, Rene; Velasco-Arias, Donaji; Martinez-Sanmiguel, Juan Jose; Diaz, David; Zumeta-Dube, Inti; Arevalo-Niño, Katiushka; Cabral-Romero, Claudio

    2013-01-01

    Multiresistance among microorganisms to common antimicrobials has become one of the most significant concerns in modern medicine. Nanomaterials are a new alternative to successfully treat the multiresistant microorganisms. Nanostructured materials are used in many fields, including biological sciences and medicine. Recently, it was demonstrated that the bactericidal activity of zero-valent bismuth colloidal nanoparticles inhibited the growth of Streptococcus mutans; however the antimycotic potential of bismuth nanostructured derivatives has not yet been studied. The main objective of this investigation was to analyze the fungicidal activity of bismuth oxide nanoparticles against Candida albicans, and their antibiofilm capabilities. Our results showed that aqueous colloidal bismuth oxide nanoparticles displayed antimicrobial activity against C. albicans growth (reducing colony size by 85%) and a complete inhibition of biofilm formation. These results are better than those obtained with chlorhexidine, nystatin, and terbinafine, the most effective oral antiseptic and commercial antifungal agents. In this work, we also compared the antimycotic activities of bulk bismuth oxide and bismuth nitrate, the precursor metallic salt. These results suggest that bismuth oxide colloidal nanoparticles could be a very interesting candidate as a fungicidal agent to be incorporated into an oral antiseptic. Additionally, we determined the minimum inhibitory concentration for the synthesized aqueous colloidal Bi2O3 nanoparticles.

  20. Determination of bismuth in pharmaceutical products using phosphoric acid as molecular probe by resonance light scattering.

    PubMed

    Yun, Yanru; Cui, Fengling; Geng, Shaoguang; Jin, Jianhua

    2012-01-01

    A novel method for the sensitive determination of bismuth(III) in pharmaceutical products using phosphoric acid as a molecular probe by resonance light scattering (RLS) is discussed. In 0.5 mol/L phosphoric acid (H3 PO4) medium, bismuth(III) reacted with PO4 (3-) to form an ion association compound, which resulted in the significant enhancement of RLS intensity and the appearance of the corresponding RLS spectral characteristics. The maximum scattering peak of the system existed at 364 nm. Under optimal conditions, there was linear relationship between the relative intensity of RLS and concentration of bismuth(III) in the range of 0.06-10.0 µg/mL for the system. A low detection limit for bismuth(III) of 3.22 ng/mL was achieved. The relative standard deviations (RSD) for the determination of 0.40 and 0.80 µg/mL bismuth(III) were 2.1% and 1.1%, respectively, for five determinations. Based on this fact, a simple, rapid, and sensitive method was developed for the determination of bismuth(III) at nanogram level by RLS technique with a common spectrofluorimeter. This analytical system was successfully applied to determine the trace amounts of bismuth(III) in pharmaceutical products, which was in good agreement with the results obtained by atomic absorption spectrometry (AAS).

  1. Helicobacter pylori: treatment with combinations of pivampicillin and tripotassium dicitrato bismuthate.

    PubMed

    Weil, J; Bell, G D; Powell, K; Morden, A; Harrison, G; Gant, P W; Trowell, J E; Burridge, S

    1991-10-01

    Fifty Helicobacter pylori- (H. pylori) positive patients entered an open study and were assigned to one of four treatment regimens comprising: pivampicillin (500 mg b.d.) for 2 weeks +/- tripotassium dicitrato bismuthate (tablet or liquid form) for one month. The 14C-urea breath test was used to evaluate clearance (negative at the end of treatment) and eradication (negative at 1 month post-treatment) of H. pylori. Clearance rates were 20% (2/10) after pivampicillin alone, 86% (12/14) after tripotassium dicitrato bismuthate tablets (240 mg b.d.) plus pivampicillin, 67% (6/9) after tripotassium dicitrato bismuthate tablets (120 mg q.d.s.) plus pivampicillin, and 100% (13/13) after tripotassium dicitrato bismuthate liquid (120 mg in 5 ml q.d.s) plus pivampicillin. The eradication rates were 0% (0/10), 13% (2/15), 0% (0/11) and 54% (7/13), respectively. Combination of the results from the 2 tripotassium dicitrato bismuthate tablet/pivampicillin groups gave an eradication rate of 7.7% (2/26) which was significantly lower than the 53.9% (7/13) obtained with tripotassium dicitrato bismuthate liquid/pivampicillin (P less than 0.02). In conclusion, a liquid tripotassium dicitrato bismuthate pivampicillin combination may be of special use in the treatment of H. pylori-positive patients when triple therapy is contraindicated (e.g. patient sensitivity/allergy to metronidazole) or when the H. pylori isolate is resistant to metronidazole.

  2. Nano-scaled top-down of bismuth chalcogenides based on electrochemical lithium intercalation

    NASA Astrophysics Data System (ADS)

    Chen, Jikun; Zhu, Yingjie; Chen, Nuofu; Liu, Xinling; Sun, Zhengliang; Huang, Zhenghong; Kang, Feiyu; Gao, Qiuming; Jiang, Jun; Chen, Lidong

    2011-12-01

    A two-step method has been used to fabricate nano-particles of layer-structured bismuth chalcogenide compounds, including Bi2Te3, Bi2Se3, and Bi2Se0.3Te2.7, through a nano-scaled top-down route. In the first step, lithium (Li) atoms are intercalated between the van der Waals bonded quintuple layers of bismuth chalcogenide compounds by controllable electrochemical process inside self-designed lithium ion batteries. And in the second step, the Li intercalated bismuth chalcogenides are subsequently exposed to ethanol, in which process the intercalated Li atoms would explode like atom-scaled bombs to exfoliate original microscaled powder into nano-scaled particles with size around 10 nm. The influence of lithium intercalation speed and amount to three types of bismuth chalcogenide compounds are compared and the optimized intercalation conditions are explored. As to maintain the phase purity of the final nano-particle product, the intercalation lithium amount should be well controlled in Se contained bismuth chalcogenide compounds. Besides, compared with binary bismuth chalcogenide compound, lower lithium intercalation speed should be applied in ternary bismuth chalcogenide compound.

  3. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements.

    PubMed

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-09-26

    Ohmic contact electrodes for four-wire resistance and Hall measurements were fabricated on an individual single-crystal bismuth nanowire encapsulated in a cylindrical quartz template. Focused ion beam processing was utilized to expose the side surfaces of the bismuth nanowire in the template, and carbon and tungsten electrodes were deposited on the bismuth nanowire in situ to achieve electrical contacts. The temperature dependence of the four-wire resistance was successfully measured for the bismuth nanowire, and a difference between the resistivities of the two-wire and four-wire methods was observed. It was concluded that the two-wire method was unsuitable for estimation of the resistivity due to the influence of contact resistance, even if the magnitude of the bismuth nanowire resistance was greater than the kilo-ohm order. Furthermore, Hall measurement of a 4-μm-diameter bismuth microwire was also performed as a trial, and the evaluated temperature dependence of the carrier mobility was in agreement with that for bulk bismuth, which indicates that the carrier mobility was successfully measured using this technique. PACS: 81.07.Gf.

  4. Bismuth oxide aqueous colloidal nanoparticles inhibit Candida albicans growth and biofilm formation

    PubMed Central

    Hernandez-Delgadillo, Rene; Velasco-Arias, Donaji; Martinez-Sanmiguel, Juan Jose; Diaz, David; Zumeta-Dube, Inti; Arevalo-Niño, Katiushka; Cabral-Romero, Claudio

    2013-01-01

    Multiresistance among microorganisms to common antimicrobials has become one of the most significant concerns in modern medicine. Nanomaterials are a new alternative to successfully treat the multiresistant microorganisms. Nanostructured materials are used in many fields, including biological sciences and medicine. Recently, it was demonstrated that the bactericidal activity of zero-valent bismuth colloidal nanoparticles inhibited the growth of Streptococcus mutans; however the antimycotic potential of bismuth nanostructured derivatives has not yet been studied. The main objective of this investigation was to analyze the fungicidal activity of bismuth oxide nanoparticles against Candida albicans, and their antibiofilm capabilities. Our results showed that aqueous colloidal bismuth oxide nanoparticles displayed antimicrobial activity against C. albicans growth (reducing colony size by 85%) and a complete inhibition of biofilm formation. These results are better than those obtained with chlorhexidine, nystatin, and terbinafine, the most effective oral antiseptic and commercial antifungal agents. In this work, we also compared the antimycotic activities of bulk bismuth oxide and bismuth nitrate, the precursor metallic salt. These results suggest that bismuth oxide colloidal nanoparticles could be a very interesting candidate as a fungicidal agent to be incorporated into an oral antiseptic. Additionally, we determined the minimum inhibitory concentration for the synthesized aqueous colloidal Bi2O3 nanoparticles. PMID:23637533

  5. Ab initio electronic structure and optical conductivity of bismuth tellurohalides

    NASA Astrophysics Data System (ADS)

    Schwalbe, Sebastian; Wirnata, René; Starke, Ronald; Schober, Giulio A. H.; Kortus, Jens

    2016-11-01

    We investigate the electronic structure, dielectric, and optical properties of bismuth tellurohalides BiTe X (X =I , Cl, Br) by means of all-electron density functional theory. In particular, we present the ab initio conductivities and dielectric tensors calculated over a wide frequency range, and compare our results with the recent measurements by Akrap et al. [Phys. Rev. B 90, 035201 (2014), 10.1103/PhysRevB.90.035201], Makhnev et al. [Opt. Spectrosc. 117, 764 (2014), 10.1134/S0030400X14110125], and Rusinov et al. [JETP Lett. 101, 507 (2015), 10.1134/S0021364015080147]. We show how the low-frequency branch of the optical conductivity can be used to identify characteristic intra- and interband transitions between the Rashba spin-split bands in all three bismuth tellurohalides. We further calculate the refractive indices and dielectric constants, which in turn are systematically compared to previous predictions and measurements. We expect that our quantitative analysis will contribute to the general assessment of bulk Rashba materials for their potential use in spintronics devices.

  6. Alpha decay half-life of bismuth isotopes

    NASA Astrophysics Data System (ADS)

    Tavares, O. A. P.; Medeiros, E. L.; Terranova, M. L.

    2005-02-01

    The observed alpha decay half-life values of favoured alpha transitions of ell = 5 in bismuth isotopes have been analysed in the framework of a model based on quantum mechanical tunnelling through a potential barrier where the centrifugal and overlapping effects are taken into account. In particular, the very recently measured alpha decay half-life value of (1.9 ± 0.2) × 1019 y for the unique naturally occurring 209Bi isotope has been reproduced by the present approach as (1.0 ± 0.3) × 1019 y. Also, the partial alpha decay half-lives for a number of unmeasured alpha transitions of ell = 5 in bismuth isotopes are predicted by the model, thus making it possible to demonstrate the influence of the 126 neutron shell closure on the alpha decay half-life. The present approach is shown to be successfully applicable to other isotopic sequences of alpha-emitter nuclides. Dedicated to Professor Cesare M G Lattes, one of the discoverers of the π-meson, on the occasion of his 80th birthday.

  7. Strong anisotropy of ferroelectricity in lead-free bismuth silicate

    NASA Astrophysics Data System (ADS)

    Seol, Daehee; Taniguchi, Hiroki; Hwang, Jae-Yeol; Itoh, Mitsuru; Shin, Hyunjung; Kim, Sung Wng; Kim, Yunseok

    2015-07-01

    Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies.Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03161c

  8. Bismuth nanoparticles-carbon nanotubes modified sensor for sulfasalazine analysis.

    PubMed

    Nigović, Biljana; Jurić, Sandra; Mitrović, Iva

    2017-03-01

    Nanocomposite of bismuth nanoparticles and carbon nanotubes in Nafion matrix was used as modifier for glassy carbon electrode in analysis of anti-inflamatory drug sulfasalazine. The nanocomposite surface exhibited exceptional synergy and remarkable enhancement effect to the voltammetric response of drug. The surface morphology and structure characterization of the modified electrodes was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and cyclic voltammetry. The sensor exhibited excellent electroanalytical performance for drug determination in comparison with bismuth film electrode. The adsorptive stripping square-wave voltammetric signal showed a good linear correlation to sulfasalazine concentration in a broad range from 5.0×10(-8) to 1.0×10(-5)M with low detection limit of 1.3×10(-8)M.The method was successfully utilised for drug quantification in human serum samples and good recoveries were obtained without interference from endogenous substances, 5-aminosalycilic acid and sulfapyridine formed after biotransformation of drug and folic acid co-administered as the supplement during sulfasalazine therapy. Additionally, the proposed sensor was successfully applied to analysis of sulfasalazine content in gastro-resistant pharmaceutical dosage forms.

  9. Superconductivity in Bismuth. A New Look at an Old Problem

    PubMed Central

    2016-01-01

    To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan’s formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy. PMID:26815431

  10. Superconductivity in Bismuth. A New Look at an Old Problem.

    PubMed

    Mata-Pinzón, Zaahel; Valladares, Ariel A; Valladares, Renela M; Valladares, Alexander

    2016-01-01

    To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan's formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy.

  11. Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions

    NASA Astrophysics Data System (ADS)

    Khanna, Atul; Bajaj, Anu

    2010-12-01

    Bismuth borate glasses and crystalline phases have outstanding luminescent and nonlinear optical properties; therefore there is lot of interest in their preparation and characterization. In this study we report the crystallization properties of bismuth borate glasses doped with trivalent ions. Glasses of the composition: xBi2O3-(100-×)B2O3 (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi2O3-1Tv2O3-59B2O3 (where Tv = Al, Nd and Eu) were prepared by melt quench technique and devitrified by heat treatment above their glass transition temperatures for several hours. The crystalline phases produced were characterized by FTIR absorption spectroscopy, DTA and X-ray diffraction. Bi3B5O12 was found to be the predominant phase in all crystallized samples containing Bi2O3 concentration of ≤40 mol %, at higher Bi2O3 concentration, we observed the formation of Bi4B2O9 phase. Glasses with Bi2O3 concentration of ≤37.5 mol % produced Bi2B8O15 phase on crystallization. The metastable BiBO3-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu3+ and Nd3+ promotes the formation of BiBO3-II phase while Al3+ doping suppresses it.

  12. New Bismuth-Substituted Hydroxyapatite Nanoparticles for Bone Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Ciobanu, Gabriela; Bargan, Ana Maria; Luca, Constantin

    2015-11-01

    New bismuth-substituted hydroxyapatite [Ca10- x Bi x (PO4)6(OH)2 where x = 0-2.5] nanoparticles were synthesized by the co-precipitation method from aqueous solutions. The structural properties of the samples were analyzed by scanning electron microscopy coupled with x-ray analysis, x-ray powder diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area analysis. The results confirm that bismuth ions have been incorporated into the hydroxyapatite lattice. The prepared nanocrystalline powders consisted of hydroxyapatite as single phase with hexagonal structure, crystal sizes smaller than 60 nm and (Bi + Ca)/P atomic ratio of around 1.67. The hydroxyapatite samples doped with Bi have mesoporous textures with pores size of around 2 nm and specific surface area in the range of 12-25 m2/g. The Bi-substituted hydroxyapatite powders are more effective against Gram-negative Escherichia coli bacteria than Gram-positive Staphylococcus aureus bacteria.

  13. Phase transition of solid bismuth under high pressure

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Yan; Xiang, Shi-Kai; Yan, Xiao-Zhen; Zheng, Li-Rong; Zhang, Yi; Liu, Sheng-Gang; Bi, Yan

    2016-10-01

    As a widely used pressure calibrator, the structural phase transitions of bismuth from phase I, to phase II, to phase III, and then to phase V with increasing pressure at 300 K have been widely confirmed. However, there are different structural versions for phase III, most of which are determined by x-ray diffraction (XRD) technology. Using x-ray absorption fine structure (XAFS) measurements combined with ab initio calculations, we show that the proposed incommensurate composite structure of bismuth of the three configurations is the best option. An abnormal continuous increase of the nearest-neighbor distance of phase III with elevated pressure is also observed. The electronic structure transformation from semimetal to metal is responsible for the complex behavior of structure transformation. Project supported by the National Natural Science Foundation of China (Grant Nos. 10904133, 11304294, 11274281, 11404006, and U1230201), the Development Foundation of China Academy of Engineering Physics (Grant Nos. 2015B0101004, 2013B0401062, and 2012A0101001), the Research Foundation of the Laboratory of Shock Wave and Detonation, China (Grant No. 9140C670201140C67282).

  14. Solar Water Splitting and Nitrogen Fixation with Layered Bismuth Oxyhalides.

    PubMed

    Li, Jie; Li, Hao; Zhan, Guangming; Zhang, Lizhi

    2017-01-17

    Hydrogen and ammonia are the chemical molecules that are vital to Earth's energy, environmental, and biological processes. Hydrogen with renewable, carbon-free, and high combustion-enthalpy hallmarks lays the foundation of next-generation energy source, while ammonia furnishes the building blocks of fertilizers and proteins to sustain the lives of plants and organisms. Such merits fascinate worldwide scientists in developing viable strategies to produce hydrogen and ammonia. Currently, at the forefronts of hydrogen and ammonia syntheses are solar water splitting and nitrogen fixation, because they go beyond the high temperature and pressure requirements of methane stream reforming and Haber-Bosch reaction, respectively, as the commercialized hydrogen and ammonia production routes, and inherit the natural photosynthesis virtues that are green and sustainable and operate at room temperature and atmospheric pressure. The key to propelling such photochemical reactions lies in searching photocatalysts that enable water splitting into hydrogen and nitrogen fixation to make ammonia efficiently. Although the past 40 years have witnessed significant breakthroughs using the most widely studied TiO2, SrTiO3, (Ga1-xZnx)(N1-xOx), CdS, and g-C3N4 for solar chemical synthesis, two crucial yet still unsolved issues challenge their further progress toward robust solar water splitting and nitrogen fixation, including the inefficient steering of electron transportation from the bulk to the surface and the difficulty of activating the N≡N triple bond of N2. This Account details our endeavors that leverage layered bismuth oxyhalides as photocatalysts for efficient solar water splitting and nitrogen fixation, with a focus on addressing the above two problems. We first demonstrate that the layered structures of bismuth oxyhalides can stimulate an internal electric field (IEF) that is capable of efficiently separating electrons and holes after their formation and of precisely channeling

  15. PRODUCTION OF PLUTONIUM FLUORIDE FROM BISMUTH PHOSPHATE PRECIPITATE CONTAINING PLUTONIUM VALUES

    DOEpatents

    Brown, H.S.; Bohlmann, E.G.

    1961-05-01

    A process is given for separating plutonium from fission products present on a bismuth phosphate carrier. The dried carrier is first treated with hydrogen fluoride at between 500 and 600 deg C whereby some fission product fluorides volatilize away from plutonium tetrafluoride, and nonvolatile fission product fluorides are formed then with anhydrous fluorine at between 400 and 500 deg C. Bismuth and plutonium distill in the form of volatile fluorides away from the nonvolatile fission product fluorides. The bismuth and plutonium fluorides are condensed at below 290 deg C.

  16. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE).

    PubMed

    Dossi, Carlo; Monticelli, Damiano; Pozzi, Andrea; Recchia, Sandro

    2016-07-22

    Mercury substitution is a big issue in electroanalysis, and the search for a suitable, and less toxic, replacement is still under development. Of all the proposed alternatives, bismuth films appear to be the most viable solution, although they are still suffering some drawbacks, particularly the influence of deposition conditions and linearity at low concentrations. In this paper, the most promising strategies for bismuth film deposition on screen-printed electrodes (surface modifications, polymeric film deposition, insoluble salt precursors) will be evaluated for trace metal analysis. Particular attention will be devoted to bismuth chemistry, aiming to rationalize their electroanalytic performance.

  17. Increased InAs quantum dot size and density using bismuth as a surfactant

    SciTech Connect

    Dasika, Vaishno D.; Krivoy, E. M.; Nair, H. P.; Maddox, S. J.; Park, K. W.; Yu, E. T.; Bank, S. R.; Jung, D.; Lee, M. L.

    2014-12-22

    We have investigated the growth of self-assembled InAs quantum dots using bismuth as a surfactant to control the dot size and density. We find that the bismuth surfactant increases the quantum dot density, size, and uniformity, enabling the extension of the emission wavelength with increasing InAs deposition without a concomitant reduction in dot density. We show that these effects are due to bismuth acting as a reactive surfactant to kinetically suppress the surface adatom mobility. This mechanism for controlling quantum dot density and size has the potential to extend the operating wavelength and enhance the performance of various optoelectronic devices.

  18. Oxidation mechanism of formic acid on the bismuth adatom-modified Pt(111) surface.

    PubMed

    Perales-Rondón, Juan Victor; Ferre-Vilaplana, Adolfo; Feliu, Juan M; Herrero, Enrique

    2014-09-24

    In order to improve catalytic processes, elucidation of reaction mechanisms is essential. Here, supported by a combination of experimental and computational results, the oxidation mechanism of formic acid on Pt(111) electrodes modified by the incorporation of bismuth adatoms is revealed. In the proposed model, formic acid is first physisorbed on bismuth and then deprotonated and chemisorbed in formate form, also on bismuth, from which configuration the C-H bond is cleaved, on a neighbor Pt site, yielding CO2. It was found computationally that the activation energy for the C-H bond cleavage step is negligible, which was also verified experimentally.

  19. Enhanced photo catalytic performance of nickel doped bismuth selenide under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Kulsi, Chiranjit; Ghosh, Amrita; Mondal, Anup; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali

    2017-03-01

    We have reported photo catalytic properties of bismuth selenide (Bi2Se3) and nickel doped (5 mol%) bismuth selenide (Bi2Se3) samples on two different dyes, congo red (CR) and rose bengal (RB) under visible-light irradiation without and with hydrogen peroxide. A maximum rate constant of 0.0365 min‑1 for RB dye has been observed for the nickel doped bismuth selenide catalyst in presence of hydrogen peroxide. A possible mechanism for improvement of photo catalytic performance has been explained based on band structure.

  20. Determination of nanogram amounts of bismuth in rocks by atomic absorption spectrometry with electrothermal atomization

    USGS Publications Warehouse

    Kane, J.S.

    1979-01-01

    Bismuth concentrations as low as 10 ng g-1 in 100-mg samples of geological materials can be determined by atomic absorption spectrometry with electrothermal atomization. After HF-HClO4 decomposition of the sample, bismuth is extracted as the iodide into methyl isobutyl ketone and is then stripped with ethylenediaminetetraacetic acid into the aqueous phase. Aliquots of this solution are pipetted into the graphite furnace and dried, charred, and atomized in an automated sequence. Atomic absorbance at the Bi 223.1-nm line provides a measure of the amount of bismuth present. Results are presented for 14 U.S. Geological Survey standard rocks. ?? 1979.

  1. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE)

    PubMed Central

    Dossi, Carlo; Monticelli, Damiano; Pozzi, Andrea; Recchia, Sandro

    2016-01-01

    Mercury substitution is a big issue in electroanalysis, and the search for a suitable, and less toxic, replacement is still under development. Of all the proposed alternatives, bismuth films appear to be the most viable solution, although they are still suffering some drawbacks, particularly the influence of deposition conditions and linearity at low concentrations. In this paper, the most promising strategies for bismuth film deposition on screen-printed electrodes (surface modifications, polymeric film deposition, insoluble salt precursors) will be evaluated for trace metal analysis. Particular attention will be devoted to bismuth chemistry, aiming to rationalize their electroanalytic performance. PMID:27455338

  2. Excited charmed mesons

    SciTech Connect

    Butler, J.N.; Shukla, S.

    1995-05-01

    The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one.

  3. Portable vibration exciter

    NASA Technical Reports Server (NTRS)

    Beecher, L. C.; Williams, F. T.

    1970-01-01

    Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.

  4. thin films by an hybrid deposition configuration: pulsed laser deposition and thermal evaporation

    NASA Astrophysics Data System (ADS)

    Escobar-Alarcón, L.; Solís-Casados, D. A.; Perez-Alvarez, J.; Romero, S.; Morales-Mendez, J. G.; Haro-Poniatowski, E.

    2014-10-01

    The aim of this work was to report the application of an hybrid deposition configuration to deposit Titanium dioxide (TiO2) thin films modified with different amounts of bismuth (Bi:TiO2). The samples were synthesized combining a TiO2 laser ablation plasma with a flux of vapor of bismuth produced by thermal evaporation. By varying the deposition rate of Bi it was possible to control the amount of Bi incorporated in the film and consequently the film properties. A detailed compositional, structural, and optical characterization by XPS, RBS, Raman spectroscopy, and UV-Vis spectrometry techniques is discussed. Photocatalytic response of the deposited thin films was studied through the degradation of a malachite green solution.

  5. Thin-film-formation study of high-Tc superconductors by resistive evaporation

    NASA Astrophysics Data System (ADS)

    Azoulay, Jacob

    1991-10-01

    Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O thin films were prepared with use of a conventional vacuum system for the evaporation of the constituents. This method produces stoichiometric films upon complete evaporation of the constituents. No thickness monitor or any other control system is required. In this study, substrates were kept at room temperature during the evaporation process. The bismuth-based thin films are shown to lose bismuth during heat treatment unless the Cu constituent is evaporated last and fully oxidized at 400 °C subsequently. Y-Ba-Cu-O films prepared by using a pulverized mixture of Y, BaF2, and Cu constituents show an improved quality over films obtained from YF3, BaF2, and Cu starting materials. This improvement is attributed to fluorine reduction in the starting-material mixture.

  6. On Emulation of Flueric Devices in Excitable Chemical Medium

    PubMed Central

    Adamatzky, Andrew

    2016-01-01

    Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ) medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies. PMID:27997561

  7. Optical Properties of Nanoscale Bismuth Selenide and Its Heterocrystals

    NASA Astrophysics Data System (ADS)

    Vargas, Anthony

    Over the past 12 years since the groundbreaking work on graphene, the field of 2D layered materials has grown by leaps and bounds as more materials are theoretically predicted and experimentically verified. These materials and their unique electronic, optical, and mechanical properties have inspired the scientific community to explore and investigate novel, fundamental physical phenomena as well create and refine technological devices which leverage the host of unique benefits which these materials possess. In the past few years, this burgeoning field has heavily moved towards combining layers of various materials into novel heterostructures. These heterostructures are an exciting area of research because of the plethora of exciting possibilities and results which arise due to the large number of heterostructure combinations and configurations. Particularly, the research into the optical properties of these layered materials and their heterostructures under confinement provides another exciting avenue for developing optoelectric devices. In this dissertation, I present work on the synthesis of Bi2Se 3 nanostructures via chemical vapor deposition (CVD) and the study of the optical properties of these nanostructures and their heterostructures with MoS2. The bulk of the current published work on Bi2Se 3 has focused on the exotic topological properties of its surface states, both interesting fundamental physics purposes as well as for studying avenues for spintronics. In contrast, the work presented here focuses on studying the optical properties of Bi2Se3 nanostructures and how these properties evolve when subjected to confinement. Specifically, the absorbance of singlecrystal Bi2Se3 with sizes tailored down to a few nanometers in diameter and a few quintuple layers (QLs) in thickness. We find a dramatically large bandgap, Eg ≥ 2.5 eV, in the smallest particles which is much higher than that seen in 1QL measurements taken with ARPES. Additionally, utilizing

  8. Ab initio study of electron energy loss spectra of bulk bismuth up to 100 eV

    NASA Astrophysics Data System (ADS)

    Timrov, Iurii; Markov, Maxime; Gorni, Tommaso; Raynaud, Michèle; Motornyi, Oleksandr; Gebauer, Ralph; Baroni, Stefano; Vast, Nathalie

    2017-03-01

    The dynamical charge-density response of bulk bismuth has been studied within time-dependent density functional perturbation theory, explicitly accounting for spin-orbit coupling. The use of the Liouville-Lanczos approach allows us to calculate electron energy loss spectra for excitation energies as large as 100 eV. Effects of 5 d semicore electronic states, spin-orbit coupling, exchange and correlation, local fields, and anisotropy are thoroughly investigated. The account of the 5 d states in the calculation turns out to be crucial to correctly describe the loss spectra above 10 eV and, in particular, the position and shape of the bulk-plasmon peak at 14.0 eV at vanishing transferred momentum. Our calculations reveal the presence of interband transitions at 16.3 eV, which had never been discussed before. The origin of the peak at 5.8 eV is revisited as due to mixed interband and collective excitations. Finally, our study supplements the lack of experiments at finite transferred momenta.

  9. C- V studies on metal-ferroelectric bismuth vanadate (Bi 2VO 5.5)-semiconductor structure

    NASA Astrophysics Data System (ADS)

    Kumari, Neelam; Parui, Jayanta; Varma, K. B. R.; Krupanidhi, S. B.

    2006-03-01

    Ferroelectric bismuth vanadate Bi 2VO 5.5 (BVO) thin films have been successfully grown on p-type Si(100) substrate by using chemical solution decomposition (CSD) technique followed by rapid thermal annealing (RTA). The crystalline nature of the films has been studied by X-ray diffraction (XRD). Atomic force microscopy (AFM) was used to study the microstructure of the films. The dielectric properties of the films were studied. The capacitance-voltage characteristics have been studied in metal-ferroelectric-insulator-semiconductor (MFIS) configuration. The dielectric constant of BVO thin films formed on Si(100) is about 146 measured at a frequency of 100 kHz at room temperature. The capacitance-voltage plot of a Bi 2VO 5.5 MFIS capacitor subjected to a dc polarizing voltages shows a memory window of 1.42 V during a sweep of ±5 V gate bias. The flatband voltage ( Vf) shifts towards the positive direction rather than negative direction. This leads to the asymmetric behavior of the C- V curve and decrease in memory window. The oxide trap density at a ramp rate of 0.2 V/s was estimated to be as high as 1.45×10 12 cm -2.

  10. Acoustically excited heated jets. 1: Internal excitation

    NASA Technical Reports Server (NTRS)

    Lepicovsky, J.; Ahuja, K. K.; Brown, W. H.; Salikuddin, M.; Morris, P. J.

    1988-01-01

    The effects of relatively strong upstream acoustic excitation on the mixing of heated jets with the surrounding air are investigated. To determine the extent of the available information on experiments and theories dealing with acoustically excited heated jets, an extensive literature survey was carried out. The experimental program consisted of flow visualization and flowfield velocity and temperature measurements for a broad range of jet operating and flow excitation conditions. A 50.8-mm-diam nozzle was used for this purpose. Parallel to the experimental study, an existing theoretical model of excited jets was refined to include the region downstream of the jet potential core. Excellent agreement was found between theory and experiment in moderately heated jets. However, the theory has not yet been confirmed for highly heated jets. It was found that the sensitivity of heated jets to upstream acoustic excitation varies strongly with the jet operating conditions and that the threshold excitation level increases with increasing jet temperature. Furthermore, the preferential Strouhal number is found not to change significantly with a change of the jet operating conditions. Finally, the effects of the nozzle exit boundary layer thickness appear to be similar for both heated and unheated jets at low Mach numbers.

  11. METHOD FOR RECOVERING PLUTONIUM VALUES FROM SOLUTION USING A BISMUTH HYDROXIDE CARRIER PRECIPITATE

    DOEpatents

    Faris, B.F.

    1961-04-25

    Carrier precipitation processes for separating plutonium values from aqueous solutions are described. In accordance with the invention a bismuth hydroxide precipitate is formed in the plutonium-containing solution, thereby carrying plutonium values from the solution.

  12. 75 FR 34360 - Listing of Color Additives Exempt From Certification; Bismuth Citrate; Confirmation of Effective...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ... level of bismuth citrate as a color additive in cosmetics intended for coloring hair on the scalp. DATES... hair on the scalp. FDA gave interested persons until April 26, 2010, to file objections or requests...

  13. The experience in handling of lead-bismuth coolant contaminated by Polonium-210

    SciTech Connect

    Pankratov, D.V.; Gromov, B.F.; Solodjankin, M.A.

    1993-12-31

    During exploitation of lead-bismuth cooled reactors a wide experience in handling of radioactive coolant containing polonium has been gained. By 1990 total time of this reactor operation has reached approximately 60 reactor years.

  14. In situ formation of bismuth nanoparticles through electron-beam irradiation in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Sepulveda-Guzman, S.; Elizondo-Villarreal, N.; Ferrer, D.; Torres-Castro, A.; Gao, X.; Zhou, J. P.; Jose-Yacaman, M.

    2007-08-01

    In this work, bismuth nanoparticles were synthesized when a precursor, sodium bismuthate, was exposed to an electron beam at room temperature in a transmission electron microscope (TEM). The irradiation effects were investigated in situ using selected-area electron diffraction, high-resolution transmission electron microscopy and x-ray energy dispersive spectroscopy. After the electron irradiation, bismuth nanoparticles with a rhombohedral structure and diameter of 6 nm were observed. The average particle size increased with the irradiation time. The electron-induced reduction is attributed to the desorption of oxygen ions. This method offers a one-step route to synthesize bismuth nanoparticles using electron irradiation, and the particle size can be controlled by the irradiation time.

  15. Corrosion by liquid lead and lead-bismuth: experimental results review and analysis

    SciTech Connect

    Zhang, Jinsuo

    2008-01-01

    Liquid metal technologies for liquid lead and lead-bismuth alloy are under wide investigation and development for advanced nuclear energy systems and waste transmutation systems. Material corrosion is one of the main issues studied a lot recently in the development of the liquid metal technology. This study reviews corrosion by liquid lead and lead bismuth, including the corrosion mechanisms, corrosion inhibitor and the formation of the protective oxide layer. The available experimental data are analyzed by using a corrosion model in which the oxidation and scale removal are coupled. Based on the model, long-term behaviors of steels in liquid lead and lead-bismuth are predictable. This report provides information for the selection of structural materials for typical nuclear reactor coolant systems when selecting liquid lead or lead bismuth as heat transfer media.

  16. Facile synthesis and shape control of bismuth nanoflowers induced by surfactants

    NASA Astrophysics Data System (ADS)

    Dai, Yunrong; Song, Yonghui

    2014-01-01

    Several nano-sized bismuth materials with different shapes were fabricated using ionic/nonionic surfactant as a synthesis agent. Ionic surfactants brought about the formation of irregular nanoparticles while nonionic surfactants directed the synthesis of uniform hexagonal nanoprisms. Among them, the nonionic surfactant Pluronic P123 (poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide), PEO20PPO70PEO20) could act as the reductant/shape-directing bifunctional agent for successfully reducing Bi3+ to Bi0 and inducing many hexagonal nanoprisms to grow from one crystal seed and finally form the graceful bismuth nanoflowers. The molding mechanism of bismuth nanoflowers might be attributed to the accommodation, stabilization and induction effects of P123 micelles for bismuth crystal seeds.

  17. Bismuth increases hydroxyl radical-scavenging activity of histamine H2-receptor antagonists.

    PubMed

    Kirkova, Margarita; Alexandrova, Albena; Yordanova, Neli

    2006-01-01

    The effects of histamine H2-receptor antagonists, alone or in a combination with bismuth, on *OH-provoked degradation of deoxyribose were studied. The histamine H2-receptor antagonists (cimetidine, ranitidine and roxatidine), themselves decreased the deoxyribose damage in Fenton-type systems. In combinations with bismuth, their inhibitory effect in Fenton system (Fe(III)/ascorbic acid + H2O2 was stronger. Moreover, unlike F(III) and Cu(II), which in the presence of ascorbic acid + H2O2 led to an increase in the *OH formation (deoxyribose damage), Bi(III) showed an opposite effect. The present results are interpreted in view of a better ( )OH scavenging activity of bismuth complexes of histamine H2-receptor antagonists as compared to that of the corresponding drugs. These findings might be one more explanation why bismuth salts, in combination with acid-reducing agents, are more effective anti-ulcer agents.

  18. Spectral behaviour of bismuth centres in different steps of the FCVD process

    SciTech Connect

    Zlenko, Alexander S; Mashinsky, Valerii M; Iskhakova, L D; Ermakov, R P; Semjonov, S L; Koltashev, V V

    2013-07-31

    The behaviour of bismuth ions in silica glass free of other dopants has been studied in different steps of the furnace chemical vapour deposition (FCVD) process. Porous layers annealed and consolidated in different atmospheres, a bismuth chloride solution in acetone for porous layer impregnation, the resultant glass preform and holey fibres drawn out under various conditions have been characterised by spectroscopic techniques and X-ray diffraction. Active bismuth centres present in the preform and luminescing in the visible and IR spectral regions persist during drawing under reducing conditions, whereas drawing under oxidising conditions eliminates such centres. Annealing under reducing conditions produces absorption bands of IR-emitting bismuth centres (IRBCs) in spectra of fibres drawn out under oxidising conditions and concurrently increases the background loss. Under the annealing conditions of this study (argon atmosphere, T{sub max} = 1100 Degree-Sign C, 30 min), the IRBC concentration reaches a maximum and then decreases, whereas the background loss increases monotonically. (fiber optics)

  19. Role of endogenous prostaglandins in protection of rat gastric mucosa by tripotassium dicitrate bismuthate.

    PubMed

    Malandrino, S; Bestetti, A; Fumagalli, G; Borsa, M; Viganó, T; Tonon, G

    1987-10-01

    Gross and microscopic examination of rat gastric mucosa demonstrated that intragastric administration to rats of tripotassium dicitrate bismuthate (TDB), a colloidal bismuth compound, protects against gastric lesions induced by 85% ethanol. Indomethacin, a prostaglandin synthetase inhibitor, significantly blocked the gastric mucosal protective effect of TDB. The release of gastric mucosal prostaglandins was greater in animals treated with TDB than in control animals, both time- and dose-dependently. These results seem to indicate involvement of prostaglandins in the action of TDB.

  20. Prevention of gastric mucosal lesions in rats by tri-potassium di-citrato bismuthate.

    PubMed

    Malandrino, S; Campagnoli, G; Borsa, M; Guidoboni, R; Tonon, G C

    1984-01-01

    Tri-potassium di-citrato bismuthate given intragastrically to rats 60 min before administration of necrotizing agents such as 85% ethanol, 0.2 N sodium hydroxide or acidified indomethacin, reduced the formation of mucosal lesions dose-dependently. Prostaglandin I2 (PGI2)-like material, determined by bioassay, was higher in the gastric mucosa of animals treated with bismuth subcitrate complex than in control animals.

  1. Comparison of radiation shielding ratios of nano-sized bismuth trioxide and molybdenum

    NASA Astrophysics Data System (ADS)

    Cho, J. H.; Kim, M. S.; Rhim, J. D.

    2015-07-01

    In this study, radiation shielding fibers using non-hazardous nano-sized bismuth trioxide and molybdenum instead of lead were developed and evaluated. Among the elements with high densities and atomic numbers, non-hazardous elements such as bismuth trioxide and molybdenum were chosen as a shielding element. Then, bismuth trioxide (Bi2O3) with average particle size 1-500 µm was ball milled for 10 min to produce a powdered form of nanoparticles with average particle size of 10-100 nm. Bismuth trioxide nanoparticles were dispersed to make a colloidal suspension, followed by spreading and hardening onto one or two sides of fabric, to create the radiation shielding fabric. The thicknesses of the shielding sheets using nano-sized bismuth and molybdenum were 0.4 and 0.7 mm. According to the lead equivalent test of X-ray shielding products suggested by KS, the equivalent dose was measured, followed by calculation of the shielding rate. The shielding rate of bismuth with 0.4 mm thickness and at 50 kVp was 90.5%, which is comparable to lead of 0.082 mm thickness. The shielding rate of molybdenum was 51.89%%, which is comparable to lead of 0.034 mm. At a thickness of 0.7 mm, the shielding rate of bismuth was 98.73%, equivalent to 0.101 mm Pb, whereas the shielding rate of molybdenum was 74.68%, equivalent to 0.045 mm Pb. In conclusion, the radiation shielding fibers using nano-sized bismuth developed in this study are capable of reducing radiation exposure by X-ray and its low-dose scatter ray.

  2. Determination of trimethylbismuth in the human body after ingestion of colloidal bismuth subcitrate.

    PubMed

    Boertz, Jens; Hartmann, Louise Michele; Sulkowski, Margareta; Hippler, Joerg; Mosel, Frank; Diaz-Bone, Roland Arturo; Michalke, Klaus; Rettenmeier, Albert Wolfgang; Hirner, Alfred Vitalis

    2009-02-01

    Biological methylation and hydride formation of metals and metalloids are ubiquitous environmental processes that can lead to the formation of chemical species with significantly increased mobility and toxicity. Whereas much is known about the interaction of metal(loid)s with microorganisms in environmental settings, little information has been gathered on respective processes inside the human body as yet. Here, we studied the biotransformation and excretion of bismuth after ingestion of colloidal bismuth subcitrate (215 mg of bismuth) to 20 male human volunteers. Bismuth absorption in the stomach and upper intestine was very low, as evidenced by the small quantity of bismuth eliminated via the renal route. Total bismuth concentrations in blood increased rapidly in the first hour after ingestion. Most of the ingested bismuth was excreted via feces during the study period. Trace levels of the metabolite trimethylbismuth [(CH(3))(3)Bi] were detected via low temperaturegas chromatography/inductively coupled plasma-mass spectrometry in blood samples and in exhaled air samples. Concentrations were in the range of up to 2.50 pg/ml (blood) and 0.8 to 458 ng/m(3) (exhaled air), with high interindividual variation being observed. Elimination routes of bismuth were exhaled air (up to 0.03 per thousand), urine (0.03-1.2%), and feces. The site of (CH(3))(3)Bi production could not be identified in the present study, but the intestinal microflora seems to be involved in this biotransformation if accompanying ex vivo studies are taken into consideration.

  3. Reactive magnetron sputtering deposition of bismuth tungstate onto titania nanoparticles for enhancing visible light photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Ratova, Marina; Kelly, Peter J.; West, Glen T.; Tosheva, Lubomira; Edge, Michele

    2017-01-01

    Titanium dioxide - bismuth tungstate composite materials were prepared by pulsed DC reactive magnetron sputtering of bismuth and tungsten metallic targets in argon/oxygen atmosphere onto anatase and rutile titania nanoparticles. The use of an oscillating bowl placed beneath the two magnetrons arranged in a co-planar closed field configuration enabled the deposition of bismuth tungstate onto loose powders, rather than a solid substrate. The atomic ratio of the bismuth/tungsten coatings was controlled by varying the power applied to each target. The effect of the bismuth tungstate coatings on the phase, optical and photocatalytic properties of titania was investigated by X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) surface area measurements, transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy and an acetone degradation test. The latter involved measurements of the rate of CO2 evolution under visible light irradiation of the photocatalysts, which indicated that the deposition of bismuth tungstate resulted in a significant enhancement of visible light activity, for both anatase and rutile titania particles. The best results were achieved for coatings with a bismuth to tungsten atomic ratio of 2:1. In addition, the mechanism by which the photocatalytic activity of the TiO2 nanoparticles was enhanced by compounding it with bismuth tungstate was studied by microwave cavity perturbation. The results of these tests confirmed that such enhancement of the photocatalytic properties is due to more efficient photogenerated charge carrier separation, as well as to the contribution of the intrinsic photocatalytic properties of Bi2WO6.

  4. Structural, electrical, and thermoelectric properties of bismuth telluride: Silicon/carbon nanocomposites thin films

    NASA Astrophysics Data System (ADS)

    Agarwal, Khushboo; Mehta, B. R.

    2014-08-01

    In this study, the effect of the presence of secondary phases on the structural, electrical, and thermoelectric properties of nanocomposite Bi2Te3 films prepared by co-sputtering of silicon and carbon with Bi2Te3 has been investigated. Growth temperature and the presence of Si and C phase are observed to have a strong effect on the topography and orientation of crystallites. X-ray diffraction study demonstrates that Bi2Te3 and Bi2Te3:C samples have preferred (0 0 15) orientation in comparison to Bi2Te3:Si sample, which have randomly oriented crystallites. Atomic force, conducting atomic force, and scanning thermal microscopy analysis show significant differences in topographical, electrical, and thermal conductivity contrasts in Bi2Te3:Si and Bi2Te3:C samples. Due to the randomly oriented crystallites and the presence of Si along the crystallite boundaries, appreciable Seebeck coefficient, higher electrical conductivity, and lower thermal conductivity is achieved resulting in relatively higher value of power factor (3.71 mW K-2 m-1) for Bi2Te3:Si sample. This study shows that by incorporating a secondary phase along crystallite boundaries, microstructural, electrical, and thermoelectric properties of the composite samples can be modified.

  5. Transport Properties of Thin Bismuth Films on InP (110) Surfaces by Scanning Tunneling Potentiometry

    NASA Astrophysics Data System (ADS)

    Feenstra, R. M.; Briner, B. G.; Chin, T. P.; Woodall, J. M.

    1996-03-01

    Charge transport in 20--30 Å thick Bi-films is studied by scanning tunneling potentiometry (STP) at room temperature. The Bi is deposited on cleaved InP(110) surfaces at temperatures near 140 K, yielding atomically flat films interspersed with 12 Å deep holes. The InP substrates contain conducting/insulating/conducting layers, which in cross-section are used to form contacts to the film, thus enabling lateral current densities as high as 8 × 10^6 A/cm^2 . Potential variations due to scattering of this lateral current is detected using STP, by locating the zero-crossing of current-voltage characteristics at each pixel in an image. Potential images reveal, on a coarse scale, a smooth ramp arising from the electric field due to phonon scattering in the film, from which an electron-phonon scattering length of >1000 Å is deduced. On a finer scale, potential steps 2--10 mV high are seen near surface holes and grain boundaries in the film. Detailed study of the ballistic scattering near the holes reveals a dipole shaped feature, which is identified as a residual resistivity dipole. *present address: Physics, Carnegie Mellon Univ., Pittsburgh PA 15213 **now at: Fritz-Haber-Institut, 14195 Berlin, briner@fhi-berlin.mpg.de

  6. Structural, electrical, and thermoelectric properties of bismuth telluride: Silicon/carbon nanocomposites thin films

    SciTech Connect

    Agarwal, Khushboo; Mehta, B. R.

    2014-08-28

    In this study, the effect of the presence of secondary phases on the structural, electrical, and thermoelectric properties of nanocomposite Bi{sub 2}Te{sub 3} films prepared by co-sputtering of silicon and carbon with Bi{sub 2}Te{sub 3} has been investigated. Growth temperature and the presence of Si and C phase are observed to have a strong effect on the topography and orientation of crystallites. X-ray diffraction study demonstrates that Bi{sub 2}Te{sub 3} and Bi{sub 2}Te{sub 3}:C samples have preferred (0 0 15) orientation in comparison to Bi{sub 2}Te{sub 3}:Si sample, which have randomly oriented crystallites. Atomic force, conducting atomic force, and scanning thermal microscopy analysis show significant differences in topographical, electrical, and thermal conductivity contrasts in Bi{sub 2}Te{sub 3}:Si and Bi{sub 2}Te{sub 3}:C samples. Due to the randomly oriented crystallites and the presence of Si along the crystallite boundaries, appreciable Seebeck coefficient, higher electrical conductivity, and lower thermal conductivity is achieved resulting in relatively higher value of power factor (3.71 mW K{sup −2} m{sup −1}) for Bi{sub 2}Te{sub 3}:Si sample. This study shows that by incorporating a secondary phase along crystallite boundaries, microstructural, electrical, and thermoelectric properties of the composite samples can be modified.

  7. Preparation of nanostructured Bi-modified TiO2 thin films by crossed-beam laser ablation plasmas

    NASA Astrophysics Data System (ADS)

    Escobar-Alarcon, L.; Solís-Casados, D. A.; González-Zavala, F.; Romero, S.; Fernandez, M.; Haro-Poniatowski, E.

    2017-01-01

    The preparation and characterization of titanium dioxide thin films modified with different amounts of bismuth using a two laser ablation plasmas configuration is reported. The plasmas were produced ablating simultaneously two different targets, one of bismuth and other of titanium dioxide, using a Nd:YAG laser with emission in the fundamental line. The elemental composition, together with the vibrational and optical properties of the deposited films were investigated as a function of the parameters of the bismuth plasma. The composition of the thin films was determined from measurements of X-ray photoelectron spectroscopy (XPS) as well as by Rutherford backscattering spectroscopy (RBS). The structural modification of the deposited material, due to the incorporation of Bi, was characterized by Raman spectroscopy. The optical properties were determined from UV-Vis spectroscopy measurements. It is found that bismuth incorporation has an important effect on the optical properties of TiO2 narrowing the band gap from 3.2 to 2.5 eV.

  8. Structural investigation of Zn doped sodium bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Bhatia, V.; Kumar, D.; Singh, D.; Singh, S. P.

    2016-05-01

    A series of Bismuth Borate Oxide Glass samples with composition x(ZnO):(15-x)Na2O:15Bi2O3:70B2O3 (variation in x is from 6 to 12 mole %) have been prepared by conventional melt quenching technique. All the chemicals used were of Analytical Grade. In order to verify the amorphous nature of the prepared samples the X-Ray Diffraction (XRD) was done. The physical and structural properties have been explored by using the techniques such as density, molar volume and FTIR in order to understand the effect of alkali and transition metal ions on the structure of these glasses. The results obtained by these techniques are in good agreement to one another and with literature as well. With the increase in the content of ZnO, the increase in density and some variations in structural coordination (ratio of BO3 & BO4 structural units) have been observed.

  9. Compatibility of structural materials with liquid bismuth, lead, and mercury

    SciTech Connect

    Weeks, J.R.

    1996-06-01

    During the 1950s and 1960s, a substantial program existed at Brookhaven National Laboratory as part of the Liquid Metal Fuel reactor program on the compatibility of bismuth, lead, and their alloys with structural materials. Subsequently, compatibility investigations of mercury with structural materials were performed in support of development of Rankine cycle mercury turbines for nuclear applications. The present talk will review present understanding of the corrosion/mass-transfer reactions of structural materials with these liquid metal coolants. Topics to be discussed include the basic solubility relationships of iron, chromium, nickel, and refractory metals in these liquid metals, the results of inhibition studies, the role of oxygen on the corrosion processes, and specialized topics such as cavitation-corrosion and liquid metal embrittlement. Emphasis will be placed on utilizing the understanding gained in this earlier work on the development of heavy liquid metal targets in spallation neutron sources.

  10. Structural properties of bismuth-bearing semiconductor alloys

    NASA Technical Reports Server (NTRS)

    Berding, M. A.; Sher, A.; Chen, A.-B.; Miller, W. E.

    1988-01-01

    The structural properties of bismuth-bearing III-V semiconductor alloys InPBi, InAsBi, and InSbBi were studied theoretically. Bond energies, bond lengths, and strain coefficients were calculated for pure AlBi, GaBi, and InBi compounds and their alloys, and predictions were made for the mixing enthalpies, miscibility gaps, and critical metastable-to-stable material transition temperatures. Miscibility calculations indicate that InSbBi will be the most miscible, and the InPBi will be the the most difficult to mix. However, calculations of the hardness of the Bi compounds indicate that, once formed, the InPBi alloy will be harder than the other Bi alloys and substantially harder than the currently favored narrow-gap semiconductor HgCdTe.

  11. Alkaline extraction of polonium from liquid lead bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Heinitz, S.; Neuhausen, J.; Schumann, D.

    2011-07-01

    The production of highly radiotoxic polonium isotopes poses serious safety concerns for the development of future nuclear systems cooled by lead bismuth eutectic (LBE). In this paper it is shown that polonium can be extracted efficiently from LBE using a mixture of alkaline metal hydroxides (NaOH + KOH) in a temperature range between 180 and 350 °C. The extraction ratio was analyzed for different temperatures, gas blankets and phase ratios. A strong dependence of the extraction performance on the redox properties of the cover gas was found. While hydrogen facilitates the removal of polonium, oxygen has a negative influence on the extraction. These findings open new possibilities to back up the safety of future LBE based nuclear facilities.

  12. Spectrophotometric determination of some catecholamine drugs using sodium bismuthate.

    PubMed

    Sorouraddin, M H; Manzoori, J L; Kargarzadeh, E; Haji Shabani, A M

    1998-12-01

    A novel spectrophotometric method is described for the determination of epinephrine (EP) and norepinephrine (NE). The method is based on the development of a red colour with sodium bismuthate, as a sensitive chromogenic reagent, in aqueous medium at pH 3. Oxidation of these catecholamines produces aminochrome derivatives which can be measured spectrophotometrically at 486.0 nm. Calibration graphs are linear in the range 4.8-800 (micromol l(-1)) for epinephrine bitartarate and 4.8-600 (micromol l(-1)) for norepinephrine bitartarate with detection limits of 0.26 (micromol l(-1)) and 2.46 (micromol l(-1)) for epinephrine and norepinephrine bitartarate salts, respectively. The method has successfully been applied to determination of these catecholamines in pharmaceutical preparations.

  13. Atomic Environment in Lead-Bismuthate Glasses Containing Manganese

    NASA Astrophysics Data System (ADS)

    Simon, V.; Bako-Szilagyi, H.; Neumann, M.; Chiuzbăian, S. G.; Simon, S.

    The atomic environment of 20MnO . 80(xBi2O3 . yPbO) glass samples having the ratio of bismuth to lead atoms of 8:1 and 3:1 was investigated with respect to the thermal induced structural changes, cationic field strength and electronic structure of the compound. The position and full width at half maximum of X-ray photoelectron peaks were estimated using spectra simulation based on the summation of Lorentzian and Gaussian functions. Data obtained from XPS core-level spectra Bi 4f, Pb 4f, Mn 2p, and O 1s indicate a reduction of glass disorder both by heat treatment and by increasing the PbO content in the samples. The cations behave essentially as network formers that could be correlated with an intermediate range structure.

  14. High thermoelectric performance of the distorted bismuth(110) layer.

    PubMed

    Cheng, L; Liu, H J; Zhang, J; Wei, J; Liang, J H; Jiang, P H; Fan, D D; Sun, L; Shi, J

    2016-07-14

    The thermoelectric properties of the distorted bismuth(110) layer are investigated using first-principles calculations combined with the Boltzmann transport equation for both electrons and phonons. To accurately predict the electronic and transport properties, the quasiparticle corrections with the GW approximation of many-body effects have been explicitly included. It is found that a maximum ZT value of 6.4 can be achieved for n-type systems, which essentially stemmed from the weak scattering of electrons. Moreover, we demonstrate that the distorted Bi layer retains high ZT values in relatively broad regions of both temperature and carrier concentration. Our theoretical work emphasizes that the deformation potential constant characterizing the electron-phonon scattering strength is an important paradigm for searching high thermoelectric performance materials.

  15. High ionic conductivity in confined bismuth oxide-based heterostructures

    NASA Astrophysics Data System (ADS)

    Sanna, Simone; Esposito, Vincenzo; Christensen, Mogens; Pryds, Nini

    2016-12-01

    Bismuth trioxide in the cubic fluorite phase ( δ - Bi 2 O 3 ) exhibits the highest oxygen ionic conductivity. In this study, we were able to stabilize the pure δ - Bi 2 O 3 at low temperature with no addition of stabilizer but only by engineering the interface, using highly coherent heterostructures made of alternative layers of δ - Bi 2 O 3 and Yttria Stabilized Zirconia (YSZ), deposited by pulsed laser deposition. The resulting [ δ - Bi 2 O 3 / YSZ ] heterostructures are found to be stable over a wide temperature range (500-750 °C) and exhibits stable high ionic conductivity over a long time comparable to the value of the pure δ - Bi 2 O 3 , which is approximately two orders of magnitude higher than the conductivity of YSZ bulk.

  16. Process dependent thermoelectric properties of EDTA assisted bismuth telluride

    NASA Astrophysics Data System (ADS)

    Kulsi, Chiranjit; Kargupta, Kajari; Banerjee, Dipali

    2016-04-01

    Comparison between the structure and thermoelectric properties of EDTA (Ethylene-diamine-tetra-acetic acid) assisted bismuth telluride prepared by electrochemical deposition and hydrothermal route is reported in the present work. The prepared samples have been structurally characterized by high resolution X-ray diffraction spectra (HRXRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopic images (HRTEM). Crystallite size and strain have been determined from Williamson-Hall plot of XRD which is in conformity with TEM images. Measurement of transport properties show sample in the pellet form (S1) prepared via hydrothermal route has higher value of thermoelectric power (S) than the electrodeposited film (S2). But due to a substantial increase in the electrical conductivity (σ) of the film (S2) over the pellet (S1), the power factor and the figure of merit is higher for sample S2 than the sample S1 at room temperature.

  17. Transport properties of phospho-vanadate glasses containing bismuth

    NASA Astrophysics Data System (ADS)

    Kolavekar, Sangeeta B.; Ayachit, N. H.; Pattar, Vinayak; Anavekar, R. V.

    2016-05-01

    Phospho-vanadate glasses containing various compositions of bismuth oxide were synthesized by melt quenching technique. Electrical conductivity has been measured over a wide range of temperature (373K-480K) and frequency (40 Hz -10 MHz) range. The data have been analyzed in the light of polaronic hopping model. The total conductivity at all the frequencies is due to both polarons and Bi2O3. It is seen that the conductivity increases with Bi2O3 content indicating that there is ionic contribution to the total conductivity in addition to electronic. The exponent `s' obtained from the power law in these glasses shows temperature dependence, which is attributed to high degree of modification in the glass network.

  18. Dielectric behavior of barium modified strontium bismuth titanate ceramic

    SciTech Connect

    Nayak, P.; Badapanda, T.; Anwar, S.; Panigrahi, S.

    2014-04-24

    Barium Modified Strontium Bismuth Titanate(SBT) ceramic with general formula Sr1−xBaxBi4Ti4O15 is prepared by solid state reaction route. The structural analysis of the ceramics was done by X-ray diffraction technique. The X-ray patterns show that all the compositions are of single phase with orthorhombic structure. The temperature dependent dielectric behavior shows that the transition temperature decreases with Ba content but the maximum dielectric constant increases. The decreases of the transition with increase in Ba{sup 2+} ion, may be due to the decrease of orthorhombicity by the incorporation of Ba{sup 2+} ion in SBT lattice.

  19. Shock-Wave Consolidation of Nanostructured Bismuth Telluride Powders

    NASA Astrophysics Data System (ADS)

    Beck, Jan; Alvarado, Manuel; Nemir, David; Nowell, Mathew; Murr, Lawrence; Prasad, Narasimha

    2012-06-01

    Nanostructured thermoelectric powders can be produced using a variety of techniques. However, it is very challenging to build a bulk material from these nanopowders without losing the nanostructure. In the present work, nanostructured powders of the bismuth telluride alloy system are obtained in kilogram quantities via a gas atomization process. These powders are characterized using a variety of methods including scanning electron microscopy, transition electron microscopy, and x-ray diffraction analysis. Then the powders are consolidated into a dense bulk material using a shock-wave consolidation technique whereby a nanopowder-containing tube is surrounded by explosives and then detonated. The resulting shock wave causes rapid fusing of the powders without the melt and subsequent grain growth of other techniques. We describe the test setup and consolidation results.

  20. Evolution towards superconductivity in granular films of bismuth

    NASA Astrophysics Data System (ADS)

    Parendo, Kevin A.; Tan, K. H. Sarwa B.; Goldman, A. M.

    2007-09-01

    The thickness-tuned two-dimensional insulator-superconductor transition has been investigated in ultrathin, granular films of amorphous bismuth. “Double reentrance” was observed in the resistance vs temperature. We suggest that the reentrance into the insulating state results from the opening of the energy gap on superconducting grains or clusters coupled by quasiparticle tunneling, and that the reentrance into the superconducting state is a consequence of the onset of intercluster Josephson coupling leading to global phase coherence. Measurements of voltage fluctuations have also been carried out. For insulators, the first power spectra exhibit 1/f2 frequency dependence and the second spectra are white, which is consistent with uncorrelated fluctuations. The first power spectra gradually change from having a 1/f2 frequency dependence in the insulating state to being independent of frequency in the superconducting state. There is no specific feature of the noise that can be associated with the onset of superconductivity

  1. Viability of Bismuth as a Green Substitute for Lead in Jacketed .357 Magnum Revolver Bullets

    NASA Astrophysics Data System (ADS)

    Jenkins, Joel

    In seeking to develop environmentally friendly lead-free non-toxic bullets, the research ballistically evaluated the performance of copper-jacketed handgun bullets containing a pure bismuth core. The lead was first removed from 140 grain Hornady(TM) XTPRTM bullets of 38 caliber (.357 diameter) by melting. The empty jackets were then refilled with pure bismuth, including the forming of a correctly sized hollow-point cavity. Due to the lower density of bismuth as compared to lead, the bismuth-cored bullets consistently weighed 125 gains. Conveniently this allowed direct comparison to commercially available 125 grain Hornady(TM) XTPRTM lead-cored bullets of 38 caliber. Both bismuth-cored and lead-cored versions of the 125 grain bullets had identical nose dimensions and jacket material, the only dimensional difference being the bullet length below the cannelure. Shooting took place at an outdoor range using a 357 Magnum Ruger(TM) SP101RTM revolver with 3" barrel as the test weapon. FBI protocols were followed when firing through clothing, wallboard, plywood, steel plates and laminated glass. Wound paths and bullets were captured in ballistic gelatin, with data collected for velocity, penetration, expansion, and weight retention. Bismuth compared favorably with lead in all but the laminated glass test, where it under penetrated due to jacket separation.

  2. Enhanced detection of quantum dots labeled protein by simultaneous bismuth electrodeposition into microfluidic channel.

    PubMed

    Medina-Sánchez, Mariana; Miserere, Sandrine; Cadevall, Miquell; Merkoçi, Arben

    2016-02-01

    In this study, we propose an electrochemical immunoassay into a disposable microfluidic platform, using quantum dots (QDs) as labels and their enhanced detection using bismuth as an alternative to mercury electrodes. CdSe@ZnS QDs were used to tag human IgG as a model protein and detected through highly sensitive stripping voltammetry of the dissolved metallic component (cadmium in our case). The modification of the screen printed carbon electrodes (SPCEs) was done by a simple electrodeposition of bismuth that was previously mixed with the sample containing QDs. A magneto-immunosandwich assay was performed using a micromixer. A magnet placed at its outlet in order to capture the magnetic beads used as solid support for the immunoassay. SPCEs were integrated at the end of the channel as detector. Different parameters such as bismuth concentration, flow rate, and incubation times, were optimized. The LOD for HIgG in presence of bismuth was 3.5 ng/mL with a RSD of 13.2%. This LOD was about 3.3-fold lower than the one obtained without bismuth. Furthermore, the sensitivity of the system was increased 100-fold respect to experiments carried out with classical screen-printed electrodes, both in presence of bismuth.

  3. Comparison of bismuth citrate and 5-aminosalicylic acid enemas in distal ulcerative colitis: a controlled trial.

    PubMed Central

    Pullan, R D; Ganesh, S; Mani, V; Morris, J; Evans, B K; Williams, G T; Rhodes, J

    1993-01-01

    An enema that contained a complex of bismuth citrate and polyacrylate was compared with 5-aminosalicylic acid (5-ASA) enemas for treatment of distal ulcerative colitis. The multicentre trial involving 63 patients was randomised and double blind with enemas given over four weeks; clinical, sigmoidoscopic, and histological assessments were made. Improvements were seen in both treatment groups. Clinical remission was seen in 18 of 32 patients treated with 5-ASA and 12 of 31 patients treated with bismuth citrate-carbomer (chi 2 1.94; p = 0.16). Sigmoidoscopic remission occurred in 20 of 32 patients in the 5-ASA group and 15 of 31 patients given bismuth (chi 2 1.27; p = 0.26). Improvement of rectal biopsy histology by at least one grade was seen in 16 of 32 patients in the 5-ASA group and 14 of 31 patients with bismuth (chi 2 0.15; p = 0.70). Analysis of covariance gave no significant difference between groups, although there was a trend favouring 5-ASA. There was no evidence of bismuth accumulation during the trial. Bismuth enemas may offer a new therapeutic option in distal ulcerative colitis. PMID:8504970

  4. Adverse events with bismuth salts for Helicobacter pylori eradication: Systematic review and meta-analysis

    PubMed Central

    Ford, Alexander C; Malfertheiner, Peter; Giguère, Monique; Santana, José; Khan, Mostafizur; Moayyedi, Paul

    2008-01-01

    AIM: To assess the safety of bismuth used in Helicobacter pylori (H pylori) eradication therapy regimens. METHODS: We conducted a systematic review and meta-analysis. MEDLINE and EMBASE were searched (up to October 2007) to identify randomised controlled trials comparing bismuth with placebo or no treatment, or bismuth salts in combination with antibiotics as part of eradication therapy with the same dose and duration of antibiotics alone or, in combination, with acid suppression. Total numbers of adverse events were recorded. Data were pooled and expressed as relative risks with 95% confidence intervals (CI). RESULTS: We identified 35 randomised controlled trials containing 4763 patients. There were no serious adverse events occurring with bismuth therapy. There was no statistically significant difference detected in total adverse events with bismuth [relative risk (RR) = 1.01; 95% CI: 0.87-1.16], specific individual adverse events, with the exception of dark stools (RR = 5.06; 95% CI: 1.59-16.12), or adverse events leading to withdrawal of therapy (RR = 0.86; 95% CI: 0.54-1.37). CONCLUSION: Bismuth for the treatment of H pylori is safe and well-tolerated. The only adverse event occurring significantly more commonly was dark stools. PMID:19109870

  5. Influence of hydroxycarboxylic acids on the water solubility of various bismuth compounds.

    PubMed

    Heinemann, A; Strugala, G; Elsenhans, B

    1995-01-01

    In an equilibrium dialysis assay (bismuth being determined by atomic absorption spectrometry) a constant amount of bismuth (Bi, CAS 7440-69-9) (final maximum conc. 50 mumol Bi/l) was dialyzed against solutions with increasing concentrations of the chelators (0-25 mmol/l). At pH 5, 50% of Bi(III) nitrate was soluble in solutions with 0.3, 6.3, 13.4 and 14.6 mmol/l of edetic acid (EDTA), citric, tartaric and malic acid, respectively. At the highest concentration applied, lactic acid kept 7% of bismuth in solution. Without any chelator, bismuth was found to be essentially insoluble (limit of detection: approx. 4 nmol Bi/l). A concentration-dependent increase in solubility was found also for the other bismuth compounds; the sequence of the solubilizing capacity of the chelators was the same as for Bi(III) nitrate. Lowering the pH to 3 generally increased and raising the pH to 7, decreased the solubility of bismuth.

  6. Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm

    PubMed Central

    Hernandez-Delgadillo, Rene; Velasco-Arias, Donaji; Diaz, David; Arevalo-Niño, Katiushka; Garza-Enriquez, Marianela; De la Garza-Ramos, Myriam A; Cabral-Romero, Claudio

    2012-01-01

    Background and methods Despite continuous efforts, the increasing prevalence of resistance among pathogenic bacteria to common antibiotics has become one of the most significant concerns in modern medicine. Nanostructured materials are used in many fields, including biological sciences and medicine. While some bismuth derivatives has been used in medicine to treat vomiting, nausea, diarrhea, and stomach pain, the biocidal activity of zerovalent bismuth nanoparticles has not yet been studied. The objective of this investigation was to analyze the antimicrobial activity of bismuth nanoparticles against oral bacteria and their antibiofilm capabilities. Results Our results showed that stable colloidal bismuth nanoparticles had 69% antimicrobial activity against Streptococcus mutans growth and achieved complete inhibition of biofilm formation. These results are similar to those obtained with chlorhexidine, the most commonly used oral antiseptic agent. The minimal inhibitory concentration of bismuth nanoparticles that interfered with S. mutans growth was 0.5 mM. Conclusion These results suggest that zerovalent bismuth nanoparticles could be an interesting antimicrobial agent to be incorporated into an oral antiseptic preparation. PMID:22619547

  7. Novel bismuth tri-iodide nanostructures obtained by the hydrothermal method and electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Aguiar, Ivana; Olivera, Alvaro; Mombrú, Maia; Bentos Pereira, Heinkel; Fornaro, Laura

    2017-01-01

    Bismuth tri-iodide is a layered compound semiconductor which has suitable properties as material for ionizing radiation detection devices. Monocrystals and polycrystalline thin films have been studied for this application, but only recently, the development of nanostructures of this compound has emerged as an interesting alternative for using such nanostructures in new types of radiation detectors or for including them in other applications. Considering this, we present in this work BiI3 nanoparticles successfully synthesized by the hydrothermal method, using a Teflon-lined stainless steel autoclave, at a temperature of 180 °C during 8-20 h, with BiCl3 and NaI as source materials. We characterized the nanoparticles by X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron dispersive spectroscopy (EDS). We obtained small rounded or hexagonal particles (10-20 nm in size) and larger structures. The maximum orientation of the nanostructures is along the (0 0 l) family planes and occurs after 16 h of synthesis, which arises as the best condition for obtaining BiI3 oriented nanostructures. When a 100 kV TEM electron beam was converged on the larger structures, we obtained highly oriented BiI3 hexagonal and rod shaped nanostructures. We found that particles' shape does not depend on the synthesis time. In addition, results were compared with the ones obtained for nanoparticles synthesized from solution. The present work is an advance in the synthesis of BiI3 nanostructures by the hydrothermal method, and is also the first step on seeking the amenable control of morphology and size of such structures using electron beam irradiation. This last process may be particularly appropriate for producing nanostructures for future applications in new devices.

  8. Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions

    SciTech Connect

    Khanna, Atul; Bajaj, Anu

    2010-12-01

    Bismuth borate glasses and crystalline phases have outstanding luminescent and nonlinear optical properties; therefore there is lot of interest in their preparation and characterization. In this study we report the crystallization properties of bismuth borate glasses doped with trivalent ions. Glasses of the composition: xBi{sub 2}O{sub 3}-(100-x)B{sub 2}O{sub 3} (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi{sub 2}O{sub 3}-1Tv{sub 2}O{sub 3}-59B{sub 2}O{sub 3}(where Tv = Al, Nd and Eu) were prepared by melt quench technique and devitrified by heat treatment above their glass transition temperatures for several hours. The crystalline phases produced were characterized by FTIR absorption spectroscopy, DTA and X-ray diffraction. Bi{sub 3}B{sub 5}O{sub 12} was found to be the predominant phase in all crystallized samples containing Bi{sub 2}O{sub 3} concentration of {<=}40 mol %, at higher Bi{sub 2}O{sub 3} concentration, we observed the formation of Bi{sub 4}B{sub 2}O{sub 9} phase. Glasses with Bi{sub 2}O{sub 3} concentration of {<=}37.5 mol % produced Bi{sub 2}B{sub 8}O{sub 15} phase on crystallization. The metastable BiBO{sub 3}-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu{sup 3+} and Nd{sup 3+} promotes the formation of BiBO{sub 3}-II phase while Al{sup 3+} doping suppresses it.

  9. Polonium problem in lead-bismuth flow target

    SciTech Connect

    Pankratov, D.V.; Yefimov, E.I.; Bugreev, M.I.

    1996-06-01

    Alpha-active polonium nuclides Po198 - Po210 are formed in a lead-bismuth target as results of reactions Bi{sup 209}(n,{gamma})Bi{sup 210} {yields} Po{sup 210}, Bi{sup 209}(p,xn)Po{sup 210} {yields} Po{sup 210 {minus} x} (x = 1-12), Pb{sup 208}({alpha},xn) {yields} Po{sup 210 {minus} x + 2} (x = 2-14). The most important nuclides are Po-210 (T{sub {1/2}}=138.4 day), Po-209 (T{sub {1/2}}=102 years) and Po-208 (T{sub {1/2}}=2.9 years). Polonium activity of the circuit for SINQ - conditions is about 15,000 Ci after 1-year operation. Polonium radiation hazard is connected with its output from the coolant and formation of aerosol and surface alpha-activity after the circuit break-down for repair works or in accidents. One of the important issues of polonium removal system creation is containing and storing polonium removed. Its storage in solidified alkaline is not expedient because of secondary neutron formation as a result of ({alpha},n) - reaction on oxygen and sodium nucleus. The estimations carried out demonstrated that by polonium concentration {approx} 100 Ci/l neutron current on the container surface can reach {approx} 10{sup 4}n/(cm{sup 2}s). Concentration and storage of polonium in solidified lead-bisumth seems the most convenient. The calculations demonstrated that in a 100 l container 50,000 Ci of polonium can be stored (as much as 3 times more than 1-year polonium product in SINQ-conditions) under temperature in the container less than melting point of lead bismuth (the wall temperature is about 100{degrees}C).

  10. Development of high volume fraction SiCP/Al composite-bismuthate glass metal plus dielectric films optics Au-mirror

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Qu, Shengguan; Li, Xiang-Long

    2017-01-01

    This paper reports the development of high volume fraction SiCP/Al composite-bismuthate glass multilayer films optics Au-mirror with high reflectivity in a wavelength range of 760 to 1000 nm. Multilayer films were fabricated using an radio frequency-magnetron sputtering deposition system. The measured reflectivity of Ta2O5/SiO2/Au/Cr metal plus dielectric films optics Au-mirror could reach up to ≥97%. Then, on the basis of experiments, a Φ75-mm high volume fraction SiCP/Al composite-bismuthate glass multilayer optical Au-mirror for a wavelength range of 760 to 1000 nm was manufactured. The tested results indicate that a peak-to-valley value of 0.854λ (λ=632.8 nm) was achieved on the Au-mirror surface, and the slope deviation error for the flat surface was lower than 0.153λ root mean square. The surface roughness of Ta2O5/SiO2/Au/Cr multilayer thin films was 1.30 nm (Ra).

  11. Controlled electrodeposition of bismuth nanocatalysts for the solution-liquid-solid synthesis of CdSe nanowires on transparent conductive substrates.

    PubMed

    Reim, Natalia; Littig, Alexander; Behn, Dino; Mews, Alf

    2013-12-11

    Semiconductor nanowires (NWs) composed of cadmium selenide (CdSe) have been directly grown on transparent conductive substrates via the solution-liquid-solid (SLS) approach using electrodeposited bismuth nanoparticles (Bi NPs) as catalyst. Bi NPs were fabricated on indium tin oxide (ITO) surfaces from a bismuth trichloride solution using potentiostatic double-pulse techniques. The size and density of electrodeposited Bi NPs were controlled by the pulse parameters. Since the NW diameter is governed by the dimension of the Bi catalyst, the electrodeposition is a reliable method to synthesize nanowires directly on substrates with a desired size and density. We show that the density can be adjusted from individual NWs on several square micrometer to very dense NW networks. The diameter can be controlled between thick nanowires above 100 nm to very thin NW of 7 nm in diameter, which is well below the respective exciton dimension. Hence, especially the thinnest NWs exhibit diameter-dependent photoluminescence energies as a result of quantum confinement effects in the radial dimension.

  12. The network modifier and former role of the bismuth ions in the bismuth-lead-germanate glasses.

    PubMed

    Rada, M; Rus, L; Rada, S; Culea, E; Rusu, T

    2014-11-11

    The present work is focused on the enhancement of network former environment in lead-germanate glasses by bismuth ions doping. A series of bismuth-lead-germanate glasses with the xBi2O3·(100-x)[7GeO2·3PbO] composition glass where 0≤x≤30 mol% Bi2O3 were synthesized by melt-quenching method. The FTIR, UV-VIS spectroscopy and cyclic voltammetry were conducted on these samples to evaluate the doping effect of structure of the host matrix network. Our results indicate that direct incorporation of Bi2O3 into the lead-germanate network modifies the lead-germanate network and the internal structure of glass network is rearranged. The structural flexibility of the lead-germanate network is possible due to its incapacity to accommodate with the excess of oxygen atoms and the creation of bridging oxygen ions. Optical gap energy and refractive index were obtained as a function of Bi2O3 content. Gap energy values decrease as Bi2O3 content increased from 0 to 10 mol%. Further increase of Bi2O3 concentration beyond 10 mol% increased the gap energy values. These behaviors of the glass system can be explained by two mechanisms: (i) for x≤10 mol% Bi2O3--increase of degree of disorder of the host matrix because Bi2O3 is network modifier and (ii) for x>10 mol%--Bi2O3 acts as a network former. Cyclic voltammetry measurements using the glass system with 10Bi2O3·90[7GeO2·3PbO] composition as working electrode show the mobility of the lead ions, in agreement with UV-VIS data.

  13. Two-color temporal focusing multiphoton excitation imaging with tunable-wavelength excitation

    NASA Astrophysics Data System (ADS)

    Lien, Chi-Hsiang; Abrigo, Gerald; Chen, Pei-Hsuan; Chien, Fan-Ching

    2017-02-01

    Wavelength tunable temporal focusing multiphoton excitation microscopy (TFMPEM) is conducted to visualize optical sectioning images of multiple fluorophore-labeled specimens through the optimal two-photon excitation (TPE) of each type of fluorophore. The tunable range of excitation wavelength was determined by the groove density of the grating, the diffraction angle, the focal length of lenses, and the shifting distance of the first lens in the beam expander. Based on a consideration of the trade-off between the tunable-wavelength range and axial resolution of temporal focusing multiphoton excitation imaging, the presented system demonstrated a tunable-wavelength range from 770 to 920 nm using a diffraction grating with groove density of 830 lines/mm. TPE fluorescence imaging examination of a fluorescent thin film indicated that the width of the axial confined excitation was 3.0±0.7 μm and the shifting distance of the temporal focal plane was less than 0.95 μm within the presented wavelength tunable range. Fast different wavelength excitation and three-dimensionally rendered imaging of Hela cell mitochondria and cytoskeletons and mouse muscle fibers were demonstrated. Significantly, the proposed system can improve the quality of two-color TFMPEM images through different excitation wavelengths to obtain higher-quality fluorescent signals in multiple-fluorophore measurements.

  14. Magneto-optical visualization by Bi:YIG thin films prepared at low temperatures

    SciTech Connect

    Galstyan, Ogsen; Lee, Hanju; Lee, Kiejin; Babajanyan, Arsen; Hakhoumian, Arsen; Friedman, Barry

    2015-04-28

    A device for the imaging of magnetic fields and domain structures based on the Faraday effect has been developed using garnet thin films prepared by the metal-organic decomposition method as indicators. The sensitivity was improved by using high concentration bismuth substituted yttrium iron garnet thin films with in-plane magnetic anisotropy. Low temperature synthesis of the films (Bi{sub x}Y{sub 3−x}Fe{sub 5}O{sub 12}; x = 2) on glass substrates of thickness about 0.8 μm is described and the Faraday rotation angle is measured to be about −11°/μm.

  15. [Geochemical distribution of dissolved bismuth in the Yellow Sea and East China Sea].

    PubMed

    Wu, Xiao-Dan; Song, Jin-Ming; Wu, Bin; Li, Xue-Gang

    2014-01-01

    Occurrence level, geochemical distribution of dissolved bismuth and its coupling relationship to eco-environment were investigated in the Yellow Sea and East China Sea to explore the source and influencing factors. The results showed that the concentration of dissolved bismuth was within the range of 0-0. 029 microg x L(-1) at the surface and 0.001-0.189 microg x L(-1) at the bottom, with the averages of 0.008 and 0.016 microg x L(-1), respectively. Horizontally, low value of dissolved bismuth exhibited the bidirectional extension feature, indicating that it could trace the path of Changjiang Diluted Water. High value of dissolved bismuth was observed where the Subei Costal Current and Yellow Sea Warm Current flowed and the Changjiang Diluted Water and Zhejiang-Fujian Coastal Current met, suggesting that it was controlled by the cycle of current system. Vertically, the coastal water was fully mixed by water convection and eddy mixing, and was divided from the stratified water by strong tidal front, which blocked the transport of dissolved bismuth to the open sea. Thus, the concentration in front area was significantly higher than that in the open sea. Diurnal variation of dissolved bismuth was related to the hydrodynamic conditions (tide, suspension and thermocline) instead of the environmental factors (temperature and salinity). Positive relationship to SPM (suspended particulate matter) clarified that bismuth was prone to release from solid phase to liquid phase. Furthermore, conditions with temperature ranging 22-27 degrees C, salinity ranging 28-31 and pH ranging 7.9-8.1 were shown to be optimal for the release process.

  16. The higher excited electronic states and spin-orbit splitting of the valence band in three-dimensional assemblies of close-packed ZnSe and CdSe quantum dots in thin film form

    SciTech Connect

    Pejova, Biljana

    2008-08-15

    Optical properties of as-deposited and annealed thin films composed of three-dimensional arrays of sphalerite-type ZnSe and CdSe quantum dots (QDs), synthesized by chemical deposition, were investigated. Neglecting the S-D mixing of hole states, the lowest 'band to band' transitions in very small nanoclusters and in bulk-like clusters may be assigned as 1S{yields}1S and 1S{sub {delta}}{yields}1S, and are split by spin-orbit (SO) splitting energy of the bulk material-{delta}. The splitting energy between these transitions was found to be insensitive to QD size variations, which could be explained assuming that 1S hole states arising from valence band {gamma}{sub 7} and {gamma}{sub 8} components do not mix with higher angular momentum states and shift together to higher energies coupled via the isotropic hole mass. This implies significant difference between the SO splitting energies in the two semiconductors. Accounting for S-D mixing of hole states, the observed transitions may be attributed to the fundamental ground state-(1S{sub 3/2}, 1S{sub e}) and the ground state-(1S{sub 1/2}, 1S{sub e}) ones. The observed 'splittings' thus do not correspond exactly to SO splitting energy in both semiconductors, but are complex functions of it, as exact position of each hole energy level depends, besides on {delta}, also on other material-characteristic parameters. - Graphical abstract: Accounting for S-D mixing of hole states, the observed optical transitions in very small sphalerite-type ZnSe and CdSe nanoclusters are attributed to the ground state-(1S{sub 3/2}, 1S{sub e}) and the ground state-(1S{sub 1/2}, 1S{sub e}). The 'splittings' do not correspond to SO splitting energy, but are complex functions of it.

  17. Interaction of bismuth subsalicylate with fruit juices, ascorbic acid, and thiol-containing substrates to produce soluble bismuth products active against Clostridium difficile.

    PubMed

    Mahony, D E; Woods, A; Eelman, M D; Burford, N; Veldhuyzen van Zanten, S J O

    2005-01-01

    Bismuth subsalicylate (BSS), the active ingredient of Pepto-Bismol, has been used for many years to treat various disorders of the gastrointestinal tract. Using mass spectrometry and the agar dilution method, we determined that insoluble BSS interacts with certain dietary components and organic substrates to produce water-soluble products with activity against Clostridium difficile.

  18. Humidity sensors applicative characteristics of granularized and porous Bi2O3 thin films prepared by oxygen plasma-assisted pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Tudorache, Florin; Petrila, Iulian; Condurache-Bota, Simona; Constantinescu, Catalin; Praisler, Mirela

    2015-01-01

    Pulsed laser ablation of pure bismuth targets in a plasma discharge followed by thermal treatment as preparation method for humidity high-sensitive bismuth trioxide thin films deposited onto Si/Pt substrates were analyzed. Several thin films were deposited at different substrate temperatures during the pulsed laser deposition namely between 300 °C and 600 °C. Near to the electrical investigation, the structure and the morphology of the films as keys features for water adsorption are thoroughly investigated and correlated with their sensitivity as humidity sensors. Thus, it has been found that strong granularized Bi2O3 thin films obtained through oxygen plasma-assisted pulsed laser deposition onto Si/Pt substrate at 500 °C provide the most interesting humidity sensing characteristics.

  19. 8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER No. 2., AND GENERATOR UNITS BEHIND EXCITER No. 2 IN BACKGROUND. EXCITER No. 1 GENERATOR HAS A COVER OVER TOP HALF OF COMMUTATOR ELEMENT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Powerhouse Exciters, Rush Creek, June Lake, Mono County, CA

  20. Thin films under chemical stress

    SciTech Connect

    Not Available

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  1. Comparison of Second-Line Quadruple Therapies with or without Bismuth for Helicobacter pylori Infection.

    PubMed

    Jheng, Guang-Hong; Wu, I-Chen; Shih, Hsiang-Yao; Wu, Meng-Chieh; Kuo, Fu-Chen; Hu, Huang-Ming; Liu, Chung-Jung; Hsu, Wen-Hung; Hu, Chi-Tan; Bair, Ming-Jong; Kuo, Chao-Hung; Wu, Deng-Chyang; Hsu, Ping-I

    2015-01-01

    The bismuth-based quadruple regimen has been applied in Helicobacter pylori rescue therapy worldwide. The non-bismuth-based quadruple therapy or "concomitant therapy" is an alternative option in first-line eradication but has not been used in second-line therapy. Discovering a valid regimen for rescue therapy in bismuth-unavailable countries is important. We conducted a randomized controlled trial to compare the efficacies of the standard quadruple therapy and a modified concomitant regimen. One hundred and twenty-four patients were randomly assigned into two groups: RBTM (rabeprozole 20 mg bid., bismuth subcitrate 120 mg qid, tetracycline 500 mg qid, and metronidazole 250 mg qid) and RATM (rabeprozole 20 mg bid., amoxicillin 1 g bid., tetracycline 500 mg qid, and metronidazole 250 mg qid) for 10 days. The eradication rate of the RBTM and RATM regimen was 92.1% and 90.2%, respectively, in intention-to-treat analysis. Patients in both groups had good compliance (~96%). The overall incidence of adverse events was higher in the RATM group (42.6% versus 22.2%, P = 0.02), but only seven patients (11.5%) experienced grades 2-3 events. In conclusion, both regimens had good efficacy, compliance, and acceptable side effects. The 10-day RATM treatment could be an alternative rescue therapy in bismuth-unavailable countries.

  2. Role of bismuth in improving Helicobacter pylori eradication with triple therapy.

    PubMed

    Dore, Maria Pina; Lu, Hong; Graham, David Y

    2016-05-01

    In most regions of the world, antimicrobial resistance has increased to the point where empirical standard triple therapy for Helicobacter pylorieradication is no longer recommended. The treatment outcome in a population is calculated as the sum of the treatment success in the subpopulation with susceptible infections plus treatment success in the subpopulation with resistant infections. The addition of bismuth (i.e., 14-day triple therapy plus bismuth) can improve cure rates despite a high prevalence of antimicrobial resistance. The major bismuth effect is to add an additional 30%-40% to the success with resistant infections. The overall result is therefore dependent on the prevalence of resistance and the treatment success in the subpopulation with resistant infections (eg, with proton-pump inhibitor-amoxicillin dual therapy). Here, we explore the contribution of each component and the mechanisms of how bismuth might enhance the effectiveness of triple therapy. We also discuss the limitations of this approach and provide suggestions how triple therapy plus bismuth might be further improved.

  3. Effect of ranitidine bismuth citrate on postprandial plasma gastrin and pepsinogens.

    PubMed Central

    Fraser, A G; Lam, W M; Luk, Y W; Sercombe, J; Sawyerr, A M; Hudson, M; Samloff, I M; Pounder, R E

    1993-01-01

    Ranitidine bismuth citrate was compared with an equipotent dose of ranitidine, to determine whether the former, by an anti-Helicobacter pylori activity, would counteract the rise of gastrin resulting from ranitidine's gastric acid antisecretory activity. Twenty four men with duodenal ulcers were studied before and on the 8th day of dosing with either ranitidine bismuth citrate 800 mg twice daily or ranitidine 300 mg twice daily (double blind, randomised, parallel groups). Fasting and postprandial plasma gastrin and plasma pepsinogen I and II concentrations were measured, and a 13C-urea breath test was performed before and on the 8th day of dosing. The 13C-urea breath tests were positive in 21 patients before dosing and remained positive in nine of nine of the ranitidine dosed patients, whereas only two of 12 patients treated with ranitidine bismuth citrate remained positive. The expected rise in meal stimulated plasma gastrin with ranitidine was seen in the 12 patients who received ranitidine but, despite suppression of H pylori urease activity in 10 of 12 patients taking ranitidine bismuth citrate, there was no attenuation of the meal stimulated gastrin rise. There was no significant difference in the mean derived (4 hour) plasma pepsinogen I and II concentrations after dosing with ranitidine or ranitidine bismuth citrate. PMID:8472980

  4. Improvement of filling bismuth for x-ray absorption gratings through the enhancement of wettability

    NASA Astrophysics Data System (ADS)

    Lei, Yaohu; Liu, Xin; Li, Ji; Guo, Jinchuan; Niu, Hanben

    2016-06-01

    Filling materials with high x-ray linear absorption coefficients in high aspect-ratio (HAR) structures is a key process for the fabrication of absorption gratings used in x-ray differential phase-contrast imaging. Bismuth has been chosen as an effective filling material in micro-casting technology, because of its low cost both in price and facility use. However, repellence on structure surfaces against molten bismuth leads to an obstacle in terms of completely filling bismuth into the small-aperture and HAR microstructure formed by photo-assisted electrochemical etching in 5 inch silicon wafers. We propose and implement a novel method of surface modification to completely fill bismuth into these structures with periods of 3 μm and 42 μm, respectively, and as deep as 150 μm. The modified surface with a Bi2O3 layer covering the structure surface, including the side walls, induces an enhanced bismuth filling ratio. The superiority of the method is demonstrated by micrographs which show filled microstructures compared to the previously used method, where only a layer of 100 nm SiO2 was covered. Furthermore, we have observed that the improved micro-casting makes the absorption gratings clean surfaces, and no post treatment is needed.

  5. How reliable are environmental data on 'orphan' elements? The case of bismuth concentrations in surface waters.

    PubMed

    Filella, Montserrat

    2010-01-01

    Like all elements of the periodic table, bismuth is ubiquitously distributed throughout the environment as a result of natural processes and human activities. It is present as Bi(III) in environmental, biological and geochemical samples. Although bismuth and its compounds are considered to be non-toxic to humans, its increasing use as a replacement for lead has highlighted how little is known about its environmental and ecotoxicological behaviour. In this first critical review paper on the existing information on bismuth occurrence in natural waters, 125 papers on fresh and marine waters have been collated. Although the initial objective of this study was to establish the range of the typical concentrations of total dissolved bismuth in natural waters, this proved impossible to achieve due to the wide, and hitherto unexplained, dispersion of published data. Since analytical limitations might be one of the reasons underlying value dispersion, new analytical methods published since 2000--intended to be applied to natural waters--have also been reviewed. Disappointingly, the detection limits of the bulk of them are well above those required; they are thus of limited usefulness. Analysis of the existing information on bismuth in secondary references (i.e., books, review chapters) and on its chemical speciation in seawater revealed that the uncritical reproduction of old data is a widespread practice.

  6. Enhanced thermoelectric properties of bismuth sulfide polycrystals prepared by mechanical alloying and spark plasma sintering

    SciTech Connect

    Zhao Lidong; Zhang Boping Liu Weishu; Zhang Hailong; Li Jingfeng

    2008-12-15

    Bismuth sulfide powders were synthesized by mechanical alloying (MA) and then consolidated by spark plasma sintering (SPS) technique. In order to improve the electrical transport properties of bismuth sulfides, the carrier concentration was optimized by modifying chemical composition of sulfur through producing sulfur vacancies, and the carrier mobility was enhanced by a two-step SPS as a hot-forging process through increasing grain orientation. The electrical resistivity of bismuth sulfides was reduced to 10{sup -4} from 10{sup -2} {omega} m by optimizing sulfur content, and further lowered by hot-forging, whereby the power factor was significantly increased from 91 to 254 {mu}W/mK{sup 2}. The hot-forged Bi{sub 2}S{sub 2.90} sample showed the highest ZT=0.11 (at 523 K), which is higher than the reported value. The present work revealed that bismuth sulfide compounds as a promising candidate of thermoelectric materials can be synthesized by a simple process. - Abstract: Electrical properties of bismuth sulfides were improved by optimizing carrier concentration through modifying compositions of sulfur and enhancing carrier mobility through SPSed hot-forging. The ZT value of 0.11 was obtained, which is the maximum reported so far . Display Omitted.

  7. Preparation and characterization of nano bismuth titanate powders with high reflectivity in near-infrared waveband

    NASA Astrophysics Data System (ADS)

    Jia, Y. H.; Wu, Y. B.; Huang, Y.; Zhou, Z. H.; Shen, S.

    2017-03-01

    Nano powders with high reflectivity in near-infrared waveband have broad applications as thermal insulation materials. In this study, nano bismuth titanate powders with the reflectance to near-infrared of as high as 89.5% in average were prepared via a sol-gel method by using tetrabutyl titanate, bismuth nitrate as raw materials and citric acid, acetic acid as reaction adjuvant reagents. Furthermore, to control the reflectivity in the visible light waveband, the as-prepared nano bismuth titanate powders were further coated with nano-Ag by using NaBH4 as a reduction agent. The influence of different dispersants on reflectivity and on powder dispersibility has also been studied. SEM characterization demonstrates that PEG1000, worked as a dispersant, significantly enhances the dispersion of bismuth titanate powders comparing with non-dispersant system. UV-Vis-NIR spectra reveal that with addition amount of AgNO3 of 1.5 ml and PEG1000 as the dispersant, the Ag-coated bismuth titanate nano powders can reach about 60% of reflectance to near-infrared, while the reflectance of visible light can be controlled as low as around 14%. It is very promising for such nano powders to be used in thermal insulation glass materials.

  8. Excitability dependent pattern formation

    NASA Astrophysics Data System (ADS)

    Prabhakara, Kaumudi; Gholami, Azam; Bodenschatz, Eberhard

    2014-03-01

    On starvation, the amoebae Dictyostelium discoideum emit the chemo-attractant cyclic adenosine monophosphate (cAMP) at specific frequencies. The neighboring amoebae sense cAMP through membrane receptors and produce their own cAMP. Soon the cells synchronize and move via chemotaxis along the gradient of cAMP. The response of the amoebae to the emission of cAMP is seen as spiral waves or target patterns under a dark field microscope. The causal reasons for the selection of one or the other patterns are still unclear. Here we present a possible explanation based on excitability. The excitability of the amoebae depends on the starvation time because the gene expression changes with starvation. Cells starved for longer times are more excitable. In this work, we mix cells of different excitabilities to study the dependence of the emergent patterns on the excitability. Preliminary results show a transition from spirals to target patterns for specific excitabilities. A phase map of the patterns for different combinations of excitability and number densities is obtained. We compare our findings with numerical simulations of existing theoretical models.

  9. The development of a bismuth feed system for the very high Isp thruster with anode layer VHITAL program

    NASA Technical Reports Server (NTRS)

    Marrese-Reading, Colleen; Markusic, Tom; Polzin, Kurt; Knowles, Timothy; Mueller, Juergen

    2005-01-01

    A bismuth feed system was developed for the VHITAL Program to deliver 8-12 mg/s of bismuth vapor at a few Torr to the VHITAL-160. A carbon vaporizer developed to control vapor flow rates to the thruster.

  10. 15. POWERHOUSE INTERIOR SHOWING EXCITER No. 2 WITH EXCITER No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. POWERHOUSE INTERIOR SHOWING EXCITER No. 2 WITH EXCITER No. 1 BEHIND. OVERHEAD CRANE DANGLES AT TOP OF PHOTO. VIEW TO NORTHEAST. - Rush Creek Hydroelectric System, Powerhouse Exciters, Rush Creek, June Lake, Mono County, CA

  11. Stable high conductivity ceria/bismuth oxide bilayered electrolytes

    SciTech Connect

    Wachsman, E.D.; Jayaweera, P.; Jiang, N.; Lowe, D.M.; Pound, B.G.

    1997-01-01

    The authors have developed a high conductivity bilayered ceria/bismuth oxide anolyte/electrolyte that uses the Po{sub 2} gradient to obtain stability at the anolyte-electrolyte interface and reduced electronic conduction due to the electrolyte region. Results in terms of solid oxide fuel cell (SOFC) performance and stability are presented. These results include a 90 to 160 mV increase in open-circuit potential, depending on temperature, with the bilayered structure as compared to SOFCs fabricated from a single ceria layer. An open-circuit potential of >1.0 V was obtained at 500 C with the bilayered structure. This increase in open-circuit potential is obtained without any measurable increase in cell resistance and is stable for over 1,400 h of testing, under both open-circuit and maximum power conditions. Moreover, SOFCs fabricated from the bilayered structure result in a 33% greater power density as compared to cells with a single ceria electrolyte layer.

  12. Titanium induced structural modifications in bismuth silicate glasses

    NASA Astrophysics Data System (ADS)

    Kundu, R. S.; Dult, Meenakshi; Punia, R.; Parmar, Rajesh; Kishore, N.

    2014-04-01

    Glass system with compositions xTiO2·(60 - x)Bi2O3·40SiO2 has been prepared by standard melt quench technique. The amorphous nature of the glass samples has been ascertained by the X-ray diffraction. It is observed that density and molar volume of the studied glasses decrease with increase in TiO2 content whereas the glass transition temperature shows the reverse trend; indicating the increase in compactness of the glass structure with increase in TiO2 content. The Raman and FTIR studies reveal that on addition of TiO2, some of SiO4 tetrahedra units with three non-bridging oxygens (NBOs) per silicon are converted into SiO4 tetrahedral units with four NBO per silicon and number of network forming BiO3 pyramidal units goes on decreasing and no BiO3 pyramidal units are observed in glass composition with x = 20. Bismuth plays the role of network modifier with BiO6 octahedral units for all the studied glass compositions. TiO2 acts as network former with TiO4 tetrahedral units in all the glass compositions having titanium besides acting as network modifier TiO6 octahedral units in glass compositions with x = 10, 15 and 20. However, the glass composition with x = 15 has maximum number of TiO4 structural units among all the studied glass compositions.

  13. Dynamics of lithium ions in calcium bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Dutta, A.; Ghosh, A.

    2005-06-01

    Ion transport in Li2O-CaO-Bi2O3 glasses has been studied in the frequency range from 10Hzto2MHz and in the temperature range from 293to543K. The variation of the dc conductivity and the activation energy of these glasses with composition have been compared with those of binary lithium bismuthate glasses. It has been observed that the introduction of CaO in small amount does not effect the dc conductivity and the corresponding activation energy, but the larger amount of CaO changes them to some extent. The frequency-dependent conductivity has been studied using both conductivity and modulus formalisms. The values of the nonexponential parameter and frequency exponent are found to differ for the Li2O-CaO-Bi2O3 glasses from those for the binary Li2O-Bi2O3 glasses. The concentration of mobile Li+ ions does not change appreciably with the change in the Li2O as well as CaO content in the compositions. The increasing amount of CaO in the glass compositions for fixed Li2O content points out that CaO dilates the glass network, enhancing the migration of Li+ ions.

  14. Dynamics of lithium ions in calcium bismuthate glasses.

    PubMed

    Dutta, A; Ghosh, A

    2005-06-15

    Ion transport in Li(2)O-CaO-Bi(2)O(3) glasses has been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 293 to 543 K. The variation of the dc conductivity and the activation energy of these glasses with composition have been compared with those of binary lithium bismuthate glasses. It has been observed that the introduction of CaO in small amount does not effect the dc conductivity and the corresponding activation energy, but the larger amount of CaO changes them to some extent. The frequency-dependent conductivity has been studied using both conductivity and modulus formalisms. The values of the nonexponential parameter and frequency exponent are found to differ for the Li(2)O-CaO-Bi(2)O(3) glasses from those for the binary Li(2)O-Bi(2)O(3) glasses. The concentration of mobile Li(+) ions does not change appreciably with the change in the Li(2)O as well as CaO content in the compositions. The increasing amount of CaO in the glass compositions for fixed Li(2)O content points out that CaO dilates the glass network, enhancing the migration of Li(+) ions.

  15. Tributylphosphate extraction behavior of bismuthate-oxidized americium.

    PubMed

    Mincher, Bruce J; Martin, Leigh R; Schmitt, Nicholas C

    2008-08-04

    Higher oxidation states of americium have long been known; however, options for their preparation in acidic solution are limited. The conventional choice, silver-catalyzed peroxydisulfate, is not useful at nitric acid concentrations above about 0.3 M. We investigated the use of sodium bismuthate as an oxidant for Am (3+) in acidic solution. Room-temperature oxidation produced AmO 2 (2+) quantitatively, whereas oxidation at 80 degrees C produced AmO 2 (+) quantitatively. The efficacy of the method for the production of oxidized americium was verified by fluoride precipitation and by spectroscopic absorbance measurements. We performed absorbance measurements using a conventional 1 cm cell for high americium concentrations and a 100 cm liquid waveguide capillary cell for low americium concentrations. Extinction coefficients for the absorbance of Am (3+) at 503 nm, AmO 2 (+) at 514 nm, and AmO 2 (2+) at 666 nm in 0.1 M nitric acid are reported. We also performed solvent extraction experiments with the hexavalent americium using the common actinide extraction ligand tributyl phosphate (TBP) for comparison to the other hexavalent actinides. Contact with 30% tributyl phosphate in dodecane reduced americium; it was nevertheless extracted using short contact times. The TBP extraction of AmO 2 (2+) over a range of nitric acid concentrations is shown for the first time and was found to be analogous to that of uranyl, neptunyl, and plutonyl ions.

  16. Structural investigation of phosphate - bismuth glasses with vanadium

    NASA Astrophysics Data System (ADS)

    Stǎnescu, R.; Vedeanu, N.; Cozar, I. B.; Mǎgdaş, A.

    2013-11-01

    The xV2O5(1-dx)[0.5P2O5ṡ0.5Bi2O3] glass system with 0 ≤ x ≤ 50 mol% is investigated by IR and Raman spectroscopy. Both P2O5 and Bi2O3 oxides are known as network formers, but Bi2O3 is an unconventional one. At low content of vanadium oxide (x ≤ 5 mol%), both IR and Raman spectra are dominated by vibration bands characteristics to structural groups of phosphate and bismuthate lattices. Due to the network modifier role, vanadium oxide acts mainly on the Bi2O3 network allowing the phosphate groups to impose their characteristics absorption bands in spectra. These bands are strongly reduced for x ≥ 20 mol% due to the phosphate network depolymerization and the appearance of new vibrations characteristic to P-O-V, Bi-O-V and V-O-V groups showing the network former role of V2O5.

  17. Structural properties of bismuth-bearing semiconductor alloys

    NASA Technical Reports Server (NTRS)

    Berding, M. A.; Sher, A.; Chen, A. B.

    1986-01-01

    The structural properties of bismuth-bearing III-V semiconductor alloys are addressed. Because the Bi compounds are not known to form zincblende structures, only the anion-substituted alloys InPBi, InAsBi, and InSbBi are considered candidates as narrow-gap semiconductors. Miscibility calculations indicate that InSbBi will be the most miscible, and InPBi, with the large lattice mismatch of the constituents, will be the most difficult to mix. Calculations of the hardness of the Bi compounds indicate that, once formed, the InPBi alloy will be harder than the other Bi alloys, and substantially harder than the currently favored narrow-gap semiconductor HgCdTe. Thus, although InSbBi may be an easier material to prepare, InPBi promises to be a harder material. Growth of the Bi compounds will require high effective growth temperatures, probably attainable only through the use of nonequilibrium energy-assisted epitaxial growth techniques.

  18. Structure and thermoelectric properties of obliquely deposited bismuth films

    SciTech Connect

    Ukhlinov, G.A.; Kosakovskaya, Z. Ya.; Vigdorovich, V.N.

    1986-11-01

    Bismuth films were deposited in a vacuum evaporation equipment at a vacuum of 10/sup -2/ Pa. The microstructure of the films was investigaged by optical and scanning-electron microscopy. The orientation of the crystals was studied with a UEMV-100K electron microscope and a DRON-2 x-ray diffractometer using Fe K..cap alpha.. radiation. We carried out a survey both of the diffractograms of the films to reveal the type of planes parallel to the substrate surface and of the texture patterns from the 0009 reflection by tilting the samples relative to the horizontal axis on a GP-2 tilting attachment. The electrical resistance of the films was measured by the four-probe method and the longitudinal thermo-emf using two probes on a gradient thermoblock. The transverse thermo-emf was determined by irradiating the samples by a heat flux with an intensity of 1 W/cm/sup 2/ from an infrared heating lamp.

  19. Manganese modified structural and optical properties of bismuth silicate glasses

    NASA Astrophysics Data System (ADS)

    Dult, Meenakshi; Kundu, R. S.; Berwal, Neelam; Punia, R.; Kishore, N.

    2015-06-01

    Glass system with compositions xMnO2-(60-x) Bi2O3-40SiO2 have been synthesized by standard melt quench technique. X-ray diffraction patterns confirm the amorphous nature of as-prepared glass samples. The values of density have been measured and molar volume determined is found to decrease with increase in MnO2 content. Theoretical calculations of crystalline volume (Vc) have also been made. The glass transition temperature (Tg) determined using differential scanning calorimetry (DSC) is observed to increase with increase in MnO2 content. The structural analysis has been carried out using FTIR and Raman spectroscopy. In the present glass system, MnO2 acts as network modifier and exists in MnO6 structural units. Bismuth acts both as network former with BiO3 pyramidal units as well as network modifier with BiO6 octahedral units in the present glass system. SiO2 exists in form of SiO4 tetrahedral structural units with two non-bridging oxygens (NBO's). The optical band gap energy (Eg) has been estimated from Tauc's plot for direct transitions, it decreases with increase in manganese content.

  20. Dielectric and Impedance Spectroscopy of Barium Bismuth Vanadate Ferroelectrics

    NASA Astrophysics Data System (ADS)

    Sutar, B. C.; Choudhary, R. N. P.; Das, Piyush R.

    2014-07-01

    Structural, micro-structural and electrical properties of barium bismuth vanadate Ba(Bi0.5V0.5)O3 ceramics were investigated. X-ray diffraction (XRD) analysis of the prepared material confirmed the formation of the compound with monoclinic crystal system. Scanning electron microscopy (SEM) of the compound exhibits well-defined grains that are uniformly distributed throughout the surface of the sample. Dielectric properties of the compound were studied as a function of temperature at different frequencies. An observation of dielectric anomaly at 295 °C is due to ferroelectric phase transition that was later confirmed by the appearance of hysteresis loop. Detailed studies of complex impedance spectroscopy have provided a better understanding of the relaxation process and correlations between the microstructure-electrical properties of the materials. The nature of frequency dependence of ac conductivity obeys the Debye power law. The dc conductivity, calculated from the ac conductivity spectrum, shows the negative temperature coefficient of resistance behavior similar to that of a semiconductor.

  1. Frequency-dependent conductivity in bismuth-vanadate glassy semiconductors

    NASA Astrophysics Data System (ADS)

    Ghosh, Aswini

    1990-01-01

    The first measurements are reported for the frequency-dependent (ac) conductivity (real as well as imaginary parts) for various compositions of the bismuth-vanadate glassy semiconductors in the frequency range 102-105 Hz and in the temperature range 77-420 K. The behavior of the ac conductivity is broadly similar to what has been observed previously in many other types of amorphous semiconductors, namely, nearly linear frequency dependence and weak temperature dependence. The experimental results are analyzed with reference to various theoretical models based on quantum-mechanical tunneling and classical hopping over barriers. The analysis shows that the temperature dependence of the ac conductivity is consistent with the simple quantum-mechanical tunneling model at low temperatures; however, this model completely fails to predict the observed temperature dependence of the frequency exponent. The overlapping-large-polaron tunneling model can explain the temperature dependence of the frequency exponent at low temperatures. Fitting of this model to the low-temperature data yields a reasonable value of the wave-function decay constant. However, this model predicts the temperature dependence of the ac conductivity much higher than what actual data showed. The correlated barrier hopping model is consistent with the temperature dependence of both the ac conductivity and its frequency exponent. This model provides reasonable values of the maximum barrier heights but higher values of characteristic relaxation times.

  2. Mechanically Activated Synthesis of Nanocrystalline Powders of Ferroelectric Bismuth Vanadate

    NASA Astrophysics Data System (ADS)

    Shantha, K.; Subbanna, G. N.; Varma, K. B. R.

    1999-01-01

    Mechanical milling of a stoichiometric mixture of Bi2O3and V2O5yielded nanosized powders of bismuth vanadate, Bi2VO5.5(BiV). Structural evolution of the desired BiV phase, through an intermediate product (BiVO4), was monitored by subjecting the powders, ball milled for various durations to X-ray powder diffraction (XRD), differential thermal analysis (DTA), and transmission electron microscopic (TEM) studies. XRD studies indicate that the relative amount of the BiV phase present in the ball-milled mixture increases with increase in milling time and its formation reaches completion within 54 h of milling. Assynthesized powders were found to stabilize in the high-temperature tetragonal (γ) phase. DTA analyses of the powders milled for various durations suggest that the BiV phase-formation temperature decreases with increase in milling time. The nanometric size (30 nm) of the crystallites in the final product was confirmed by TEM and XRD studies. TEM studies clearly demonstrate the growth of BiV onBi2O3crystallites.

  3. One-dimensional Topological Edge States of Bismuth Bilayers

    NASA Astrophysics Data System (ADS)

    Drozdov, Ilya; Alexandradinata, Aris; Jeon, Sangjun; Nadj-Perge, Stevan; Ji, Huiwen; Cava, Robert; Bernevig, B. Andrei; Yazdani, Ali

    2014-03-01

    The hallmark of a time-reversal symmetry protected topologically insulating state of matter in two-dimensions (2D) is the existence of chiral edge modes propagating along the perimeter of the sample. Bilayers of bismuth (Bi), an elemental system theoretically predicted to be a Quantum Spin Hall (QSH) insulator1, has been studied with Scanning Tunneling Microscopy (STM) and the electronic structure of its bulk and edge modes has been experimentally investigated. Spectroscopic mapping with STM reveals the presence of the state bound to the edges of the Bi-bilayer. By visualizing quantum interference of the edge state quasi-particles in confined geometries we characterize their dispersion and demonstrate that their properties are consistent with the absence of backscattering. Hybridization of the edge modes to the underlying substrate will be discussed. [1] Shuichi Murakami, Phys. Rev. Lett. 97, 236805 (2006). The work at Princeton and the Princeton Nanoscale Microscopy Laboratory was supported by ARO MURI program W911NF-12-1-0461, DARPA-SPWAR Meso program N6601-11-1-4110, NSF-DMR1104612, and NSF-MRSEC programs through the Princeton Center for Complex Materials (DMR-0819860)

  4. Investigation of solution-processed bismuth-niobium-oxide films

    SciTech Connect

    Inoue, Satoshi; Ariga, Tomoki; Matsumoto, Shin; Onoue, Masatoshi; Miyasako, Takaaki; Tokumitsu, Eisuke; Shimoda, Tatsuya; Chinone, Norimichi; Cho, Yasuo

    2014-10-21

    The characteristics of bismuth-niobium-oxide (BNO) films prepared using a solution process were investigated. The BNO film annealed at 550°C involving three phases: an amorphous phase, Bi₃NbO₇ fluorite microcrystals, and Nb-rich cubic pyrochlore microcrystals. The cubic pyrochlore structure, which was the main phase in this film, has not previously been reported in BNO films. The relative dielectric constant of the BNO film was approximately 140, which is much higher than that of a corresponding film prepared using a conventional vacuum sputtering process. Notably, the cubic pyrochlore microcrystals disappeared with increasing annealing temperature and were replaced with triclinic β-BiNbO₄ crystals at 590°C. The relative dielectric constant also decreased with increasing annealing temperature. Therefore, the high relative dielectric constant of the BNO film annealed at 550°C is thought to result from the BNO cubic pyrochlore structure. In addition, the BNO films annealed at 500°C contained approximately 6.5 atm.% carbon, which was lost at approximately 550°C. This result suggests that the carbon in the BNO film played an important role in the formation of the cubic pyrochlore structure.

  5. Antibacterial effect of bismuth subsalicylate nanoparticles synthesized by laser ablation

    NASA Astrophysics Data System (ADS)

    Flores-Castañeda, Mariela; Vega-Jiménez, Alejandro L.; Almaguer-Flores, Argelia; Camps, Enrique; Pérez, Mario; Silva-Bermudez, Phaedra; Berea, Edgardo; Rodil, Sandra E.

    2015-11-01

    The antimicrobial properties of bismuth subsalicylate (BSS) nanoparticles against four opportunistic pathogens; E. coli, P. aeruginosa, S. aureus, and S. epidermidis were determined. BSS nanoparticles were synthesized by pulse laser ablation of a solid target in distilled water under different conditions. The nanoparticles were characterized using high-resolution transmission electron microscopy and absorption spectra and small angle X-ray scattering. The analysis shows that the colloids maintained the BSS structure and presented average particle size between 20 and 60 nm, while the concentration ranges from 95 to 195 mg/L. The antibacterial effect was reported as the inhibition ratio of the bacterial growth after 24 h and the cell viability was measured using the XTT assay. The results showed that the inhibition ratio of E. coli and S. epidermidis was dependant on the NPs size and/or concentration, meanwhile P. aeruginosa and S. aureus were more sensitive to the BSS nanoparticles independently of both the size and the concentration. In general, the BSS colloids with average particle size of 20 nm were the most effective, attaining inhibition ratios >80 %, similar or larger than those obtained with the antibiotic used as control. The results suggest that the BSS colloids could be used as effective antibacterial agents with potential applications in the medical area.

  6. Structural investigation of phosphate - bismuth glasses with vanadium

    SciTech Connect

    Stănescu, R.; Vedeanu, N.; Cozar, I. B.; Măgdaş, A.

    2013-11-13

    The xV{sub 2}O{sub 5}(1−dx)[0.5P{sub 2}O{sub 5}⋅0.5Bi{sub 2}O{sub 3}] glass system with 0 ≤ x ≤ 50 mol% is investigated by IR and Raman spectroscopy. Both P{sub 2}O{sub 5} and Bi{sub 2}O{sub 3} oxides are known as network formers, but Bi{sub 2}O{sub 3} is an unconventional one. At low content of vanadium oxide (x ≤ 5 mol%), both IR and Raman spectra are dominated by vibration bands characteristics to structural groups of phosphate and bismuthate lattices. Due to the network modifier role, vanadium oxide acts mainly on the Bi{sub 2}O{sub 3} network allowing the phosphate groups to impose their characteristics absorption bands in spectra. These bands are strongly reduced for x ≥ 20 mol% due to the phosphate network depolymerization and the appearance of new vibrations characteristic to P-O-V, Bi-O-V and V-O-V groups showing the network former role of V{sub 2}O{sub 5}.

  7. Studies on Seebeck Coefficient of Individual Bismuth Telluride Nanotube

    NASA Astrophysics Data System (ADS)

    Kim, Duksoo; Du, Renzhong; Yin, Yuewei; Dong, Sining; Li, Xiaoguang; Li, Qi; Tadigadapa, Srinivas

    2013-03-01

    We have studied on Seebeck coefficient (S) of freestanding individual Bismuth Telluride nanotubes using micro-fabricated thermoelectric workbench at the temperatures from 300 K to 25 K. The thermoelectric workbench is composed of three main elements: heater, thermocouple, and platinum pad. A polysilicon-gold thermocouple accurately measures the temperature, arising from the heat generated at the tips of the test sites from the polysilicon heater located 2 μm apart from the thermocouple. Platinum pads placed on top of the heater and thermocouple structures and electrically isolated from these constitute S measurement circuit. IPA solution containing Bi2Te3 nanotubes was drop-cast on the workbench and the Ebeam Induced Deposition of platinum was used to improve the electrical and thermal contacts between nanotube and platinum pads. The inner and outer diameter of nanotube is 50 nm and 70 nm, respectively. The sign of obtained S was positive which is indicating the nanotube is p-type. And the magnitude was increased compared to the bulk and nanowire types. The measured S (364 μV/K) of nanotube at T = 300 K is 1.65 times larger than that (220 μV/K) of bulk and 1.4 times larger than the previously reported value (260 μV/K) of nanowire. This work is supported by NSF MRSEC (Grant No. DMR-0820404)

  8. Thermoelectric properties of isoelectronically substituted bismuth compounds: a computational study

    NASA Astrophysics Data System (ADS)

    Liangruksa, Monrudee

    2017-03-01

    This work focuses on using isoelectronic substitution to modify electronic density of states (DOS) of bismuth (Bi) compounds for thermoelectric property modification. The calculations include first-principle density functional theory (DFT) and analytical calculations based on Mott formula. The thermoelectric materials selected in the present study are Bi compounds, i.e. Bi2Te3, Bi2Se3, Bi2Se2Te, Bi2Te2Se, Bi2O2Te, and Bi2O2Se. The results reveal that isoelectronic substitution of Se and Te atoms with O atoms (Bi2O2Te and Bi2O2Se) introduces changes in DOS around the valence band maximum and the conduction band minimum, exhibiting the figure of merit (ZT) approaching the values 0.004 and 0.03 at room temperature, for Bi2O2Se and Bi2O2Te, respectively. Though the ZT of these oxide compounds are inferior to conventional thermoelectric materials, it is known that they show better stability and less toxicity which could be the alternative materials.

  9. Experiments with the low melting indium-bismuth alloy system

    NASA Technical Reports Server (NTRS)

    Krepski, Richard P.

    1992-01-01

    The following is a laboratory experiment designed to create an interest in and to further understanding of materials science. The primary audience for this material is the junior high school or middle school science student having no previous familiarity with the material, other than some knowledge of temperature and the concepts of atoms, elements, compounds, and chemical reactions. The objective of the experiment is to investigate the indium-bismuth alloy system. Near the eutectic composition, the liquidus is well below the boiling point of water, allowing simple, minimal hazard casting experiments. Such phenomena as metal oxidation, formation of intermetallic compound crystals, and an unusual volume increase during solidification could all be directly observed. A key concept for students to absorb is that properties of an alloy (melting point, mechanical behavior) may not correlate with simple interpolation of properties of the pure components. Discussion of other low melting metals and alloys leads to consideration of environmental and toxicity issues, as well as providing some historical context. Wetting behavior can also be explored.

  10. Pressure effects on crystal and electronic structure of bismuth tellurohalides

    NASA Astrophysics Data System (ADS)

    Rusinov, I. P.; Menshchikova, T. V.; Sklyadneva, I. Yu; Heid, R.; Bohnen, K.-P.; Chulkov, E. V.

    2016-11-01

    We study the possibility of pressure-induced transitions from a normal semiconductor to a topological insulator (TI) in bismuth tellurohalides using density functional theory and tight-binding method. In BiTeI this transition is realized through the formation of an intermediate phase, a Weyl semimetal, that leads to modification of surface state dispersions. In the topologically trivial phase, the surface states exhibit a Bychkov-Rashba type dispersion. The Weyl semimetal phase exists in a narrow pressure interval of 0.2 GPa. After the Weyl semimetal-TI transition occurs, the surface electronic structure is characterized by gapless states with linear dispersion. The peculiarities of the surface states modification under pressure depend on the band-bending effect. We have also calculated the frequencies of Raman active modes for BiTeI in the proposed high-pressure crystal phases in order to compare them with available experimental data. Unlike BiTeI, in BiTeBr and BiTeCl the topological phase transition does not occur. In BiTeBr, the crystal structure changes with pressure but the phase remains a trivial one. However, the transition appears to be possible if the low-pressure crystal structure is retained. In BiTeCl under pressure, the topological phase does not appear up to 18 GPa due to a relatively large band gap width in this compound.

  11. Shape-dependent photocatalytic activities of bismuth subcarbonate nanostructures.

    PubMed

    Tang, Jiale; Cheng, Gang; Zhou, Huamin; Yang, Hao; Lu, Zhong; Chen, Rong

    2012-05-01

    Different shaped bismuth subcarbonate ((BiO)2CO3) nanostructures including irregular nanoplates, relatively uniform nanoplates and nanocubes were prepared and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflection spectroscopy (DRS) and nitrogen adsorption. The photocatalytic performance of the as-synthesized (BiO)2CO3 nanostructures on the degradation of Rhodamine B (RhB), methyl orange (MO) and methyl blue (MB) were evaluated under UV-vis light irradiation (modeling sunlight). The photocatalysis tests showed that all the different (BiO)2CO3 nanostructures displayed enhanced photodegradation performance compared with commercial (BiO)2CO3. The irregular (BiO)2CO3 nanoplates exhibited the highest photocatalytic activity on the degradation of different organic dyes. (BiO)2CO3 nanosturctures exhibited the different capacity to bleach the three organic dyes, which might be attributed to their different molecular structures. This work may provide a potential photocatalyst for the environmental pollutants treatments.

  12. Heat capacity, enthalpy and entropy of ternary bismuth tantalum oxides

    NASA Astrophysics Data System (ADS)

    Leitner, J.; Jakeš, V.; Sofer, Z.; Sedmidubský, D.; Růžička, K.; Svoboda, P.

    2011-02-01

    Heat capacity and enthalpy increments of ternary bismuth tantalum oxides Bi 4Ta 2O 11, Bi 7Ta 3O 18 and Bi 3TaO 7 were measured by the relaxation time method (2-280 K), DSC (265-353 K) and drop calorimetry (622-1322 K). Temperature dependencies of the molar heat capacity in the form Cpm =445.8+0.005451 T-7.489×10 6/ T2 J K -1 mol -1, Cpm =699.0+0.05276 T-9.956×10 6/ T2 J K -1 mol -1 and Cpm =251.6+0.06705 T-3.237×10 6/ T2 J K -1 mol -1 for Bi 3TaO 7, Bi 4Ta 2O 11 and for Bi 7Ta 3O 18, respectively, were derived by the least-squares method from the experimental data. The molar entropies at 298.15 K, S° m(298.15 K)=449.6±2.3 J K -1 mol -1 for Bi 4Ta 2O 11, S° m(298.15 K)=743.0±3.8 J K -1 mol -1 for Bi 7Ta 3O 18 and S° m(298.15 K)=304.3±1.6 J K -1 mol -1 for Bi 3TaO 7, were evaluated from the low-temperature heat capacity measurements.

  13. Bismuth nanoparticles integration into heavy metal electrochemical stripping sensor.

    PubMed

    Cadevall, Miquel; Ros, Josep; Merkoçi, Arben

    2015-08-01

    Between their many applications bismuth nanoparticles (BiNPs) are showing interest as pre-concentrators in heavy metals detection while being applied as working electrode modifiers used in electrochemical stripping analysis. From the different reported methods to synthesize BiNPs we are focused on the typical polyol method, largely used in these types of metallic and semi-metallic nanoparticles. This study presents the strategy for an easy control of the shape and size of BiNPs including nanocubes, nanosferes and triangular nanostructures. To improve the BiNP size and shape, different reducing agents (ethylene glycol or sodium hypophosphite) and stabilizers (polyvinyl pyrrolidone, PVP, in different amounts) have been studied. The efficiency of BiNPs for heavy metals analysis in terms of detection sensitivity while being used as modifiers of screen-printed carbon electrodes including the applicability of the developed device in real sea water samples is shown. A parallel study between the obtained nanoparticles and their performance in heavy metal sensing has been described in this communication.

  14. Thermoelectric characterization of individual bismuth selenide topological insulator nanoribbons

    NASA Astrophysics Data System (ADS)

    Tang, Hao; Wang, Xiaomeng; Xiong, Yucheng; Zhao, Yang; Zhang, Yin; Zhang, Yan; Yang, Juekuan; Xu, Dongyan

    2015-04-01

    Bismuth selenide (Bi2Se3) nanoribbons have attracted tremendous research interest recently to study the properties of topologically protected surface states that enable new opportunities to enhance the thermoelectric performance. However, the thermoelectric characterization of individual Bi2Se3 nanoribbons is rare due to the technological challenges in the measurements. One challenge is to ensure good contacts between the nanoribbon and electrodes in order to determine the thermal and electrical properties accurately. In this work, we report the thermoelectric characterization of individual Bi2Se3 nanoribbons via a suspended microdevice method. Through careful measurements, we have demonstrated that contact thermal resistance is negligible after the electron-beam-induced deposition (EBID) of platinum/carbon (Pt/C) composites at the contacts between the nanoribbon and electrodes. It is shown that the thermal conductivity of the Bi2Se3 nanoribbons is less than 50% of the bulk value over the whole measurement temperature range, which can be attributed to enhanced phonon boundary scattering. Our results indicate that intrinsic Bi2Se3 nanoribbons prepared in this work are highly doped n-type semiconductors, and therefore the Fermi level should be in the conduction band and no topological transport behavior can be observed in the intrinsic system.

  15. Energy levels scheme simulation of divalent cobalt doped bismuth germanate

    SciTech Connect

    Andreici, Emiliana-Laura; Petkova, Petya; Avram, Nicolae M.

    2015-12-07

    The aim of this paper is to simulate the energy levels scheme for Bismuth Germanate (BGO) doped with divalent cobalt, in order to give a reliable explanation for spectral experimental data. In the semiempirical crystal field theory we first modeled the Crystal Field Parameters (CFPs) of BGO:Cr{sup 2+} system, in the frame of Exchange Charge Model (ECM), with actually site symmetry of the impurity ions after doping. The values of CFPs depend on the geometry of doped host matrix and by parameter G of ECM. First, we optimized the geometry of undoped BGO host matrix and afterwards, that of doped BGO with divalent cobalt. The charges effect of ligands and covalence bonding between cobalt cations and oxygen anions, in the cluster approach, also were taken into account. With the obtained values of the CFPs we simulate the energy levels scheme of cobalt ions, by diagonalizing the matrix of the doped crystal Hamiltonian. Obviously, energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data and discussed. Comparison of obtained results with experimental data shows quite satisfactory, which justify the model and simulation schemes used for the title system.

  16. Tributylphosphate Extraction Behavior of Bismuthate-Oxidized Americium

    SciTech Connect

    Mincher; Leigh R. Martin; Nicholas C. Schmitt

    2008-08-01

    Higher oxidation states of americium have long been known; however, options for their preparation in acidic solution are limited. The conventional choice, silver-catalyzed peroxydisulfate, is not useful at nitric acid concentrations above about 0.3 M. We investigated the use of sodium bismuthate as an oxidant for Am3+ in acidic solution. Room-temperature oxidation produced AmO2 2+ quantitatively, whereas oxidation at 80 °C produced AmO2+ quantitatively. The efficacy of the method for the production of oxidized americium was verified by fluoride precipitation and by spectroscopic absorbance measurements. We performed absorbance measurements using a conventional 1 cm cell for high americium concentrations and a 100 cm liquid waveguide capillary cell for low americium concentrations. Extinction coefficients for the absorbance of Am3+ at 503 nm, AmO2+ at 514 nm, and AmO2 2+ at 666 nm in 0.1 M nitric acid are reported. We also performed solvent extraction experiments with the hexavalent americium using the common actinide extraction ligand tributyl phosphate (TBP) for comparison to the other hexavalent actinides. Contact with 30% tributyl phosphate in dodecane reduced americium; it was nevertheless extracted using short contact times. The TBP extraction of AmO2 2+ over a range of nitric acid concentrations is shown for the first time and was found to be analogous to that of uranyl, neptunyl, and plutonyl ions.

  17. Bismuth alloying properties in GaAs nanowires

    SciTech Connect

    Ding, Lu; Lu, Pengfei; Cao, Huawei; Cai, Ningning; Yu, Zhongyuan; Gao, Tao; Wang, Shumin

    2013-09-15

    First-principles calculations have been performed to investigate the structural, electronic and optical properties of bismuth alloying in GaAs nanowires. A typical model of Ga{sub 31}As{sub 31} nanowires is introduced for its reasonable band gap. The band gap of GaAs{sub 1−x}Bi{sub x} shrinks clearly with the increasing Bi concentration and the band edge shifts when spin–orbit coupling (SOC) is considered. The insertion of Bi atom leads to hybridization of Ga/As/Bi p states which contributes a lot around Fermi level. Scissor effect is involved. The optical properties are presented, including dielectric function, optical absorption spectra and reflectivity, which are also varied with the increasing of Bi concentrations. - Graphical abstract: Top view of Bi-doped GaAs nanowires. Ga, As, and Bi atoms are denoted with grey, purple and red balls, respectively. Display Omitted - Highlights: • A typical model of Ga{sub 31}As{sub 31} nanowires is introduced for its reasonable band gap. • The band gap of GaAs{sub 1−x}Bi{sub x} shrinks clearly with the increasing Bi concentration. • The band edge shifts when spin–orbit coupling (SOC) is considered. • The insertion of Bi atom leads to hybridization of Ga/As/Bi p states.

  18. Magnetoelectric Effect in Ceramics Based on Bismuth Ferrite

    NASA Astrophysics Data System (ADS)

    Jartych, Elżbieta; Pikula, Tomasz; Kowal, Karol; Dzik, Jolanta; Guzdek, Piotr; Czekaj, Dionizy

    2016-04-01

    Solid-state sintering method was used to prepare ceramic materials based on bismuth ferrite, i.e., (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions and the Aurivillius Bi5Ti3FeO15 compound. The structure of the materials was examined using X-ray diffraction, and the Rietveld method was applied to phase analysis and structure refinement. Magnetoelectric coupling was registered in all the materials using dynamic lock-in technique. The highest value of magnetoelectric coupling coefficient α ME was obtained for the Bi5Ti3FeO15 compound ( α ME ~ 10 mVcm-1 Oe-1). In the case of (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions, the maximum α ME is of the order of 1 and 2.7 mVcm-1 Oe-1, respectively. The magnitude of magnetoelectric coupling is accompanied with structural transformation in the studied solid solutions. The relatively high magnetoelectric effect in the Aurivillius Bi5Ti3FeO15 compound is surprising, especially since the material is paramagnetic at room temperature. When the materials were subjected to a preliminary electrical poling, the magnitude of the magnetoelectric coupling increased 2-3 times.

  19. Optical absorption and fluorescence properties of Er{sup 3+}/Yb{sup 3+} codoped lead bismuth alumina borate glasses

    SciTech Connect

    Goud, K. Krishna Murthy Reddy, M. Chandra Shekhar Rao, B. Appa

    2014-04-24

    Lead bismuth alumina borate glasses codoped with Er{sup 3+}/Yb{sup 3+} were prepared by melt quenching technique. Optical absorption, FTIR and photoluminescence spectra of these glasses have been studied. Judd-Ofelt theory has been applied to to the f ↔ f transitions for evaluating Ω{sub 2}, Ω{sub 4} and Ω{sub 6} parameters. Radiative properties like branching ratio β{sub r} and the radiative life time τ{sub R} have been determined on the basis of Judd-Ofelt theory. Upconversion emissions have been observed under 980nm laser excitation at room temperature. Green and red up-conversion emissions are centered at 530, 550 and 656 nm corresponding to {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} transitions of Er{sup 3+} respectively. The results obtained are discussed quantitatively based on the energy transfer between Yb{sup 3+} and Er{sup 3+}.

  20. Effect of Bi2O3 on spectroscopic and structural properties of Er3+ doped cadmium bismuth borate glasses.

    PubMed

    Sanghi, S; Pal, I; Agarwal, A; Aggarwal, M P

    2011-12-01

    Glasses with composition 20CdO·xBi(2)O(3)·(79.5-x)B(2)O(3) (15≤x≤35, x in mol%) containing 0.5 mol% of Er(3+) ions were prepared by melt-quench technique (1150°C in air). The amorphous nature of the glasses was confirmed by X-ray diffraction. The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The phenomenological Judd-Ofelt intensity parameters Ω(λ) (λ=2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (A(R)), radiative life time (τ(R)), branching ratios (β(R)) for various excited luminescent states. Using the near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section (σ(e)) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition (4)I(13/2)→(4)I(15/2) at 1.506 μm in Er(3+)-doped cadmium bismuth borate glasses may be useful in optical communication.

  1. Bismuth-catalyzed and doped silicon nanowires for one-pump-down fabrication of radial junction solar cells.

    PubMed

    Yu, Linwei; Fortuna, Franck; O'Donnell, Benedict; Jeon, Taewoo; Foldyna, Martin; Picardi, Gennaro; Roca i Cabarrocas, Pere

    2012-08-08

    Silicon nanowires (SiNWs) are becoming a popular choice to develop a new generation of radial junction solar cells. We here explore a bismuth- (Bi-) catalyzed growth and doping of SiNWs, via vapor-liquid-solid (VLS) mode, to fabricate amorphous Si radial n-i-p junction solar cells in a one-pump-down and low-temperature process in a single chamber plasma deposition system. We provide the first evidence that catalyst doping in the SiNW cores, caused by incorporating Bi catalyst atoms as n-type dopant, can be utilized to fabricate radial junction solar cells, with a record open circuit voltage of V(oc) = 0.76 V and an enhanced light trapping effect that boosts the short circuit current to J(sc) = 11.23 mA/cm(2). More importantly, this bi-catalyzed SiNW growth and doping strategy exempts the use of extremely toxic phosphine gas, leading to significant procedure simplification and cost reduction for building radial junction thin film solar cells.

  2. The study of optical band edge property of bismuth oxide nanowires α-Bi2O3.

    PubMed

    Ho, Ching-Hwa; Chan, Ching-Hsiang; Huang, Ying-Sheng; Tien, Li-Chia; Chao, Liang-Chiun

    2013-05-20

    The α-phase Bi(2)O(3) (α-Bi(2)O(3)) is a crucial and potential visiblelight photocatalyst material needless of intentional doping on accommodating band gap. The understanding on fundamental optical property of α-Bi(2)O(3) is important for its extended applications. In this study, bismuth oxide nanowires with diameters from tens to hundreds nm have been grown by vapor transport method driven with vapor-liquid-solid mechanism on Si substrate. High-resolution transmission electron microscopy and Raman measurement confirm α phase of monoclinic structure for the as-grown nanowires. The axial direction for the as-grown nanowires was along < 122 >. The band-edge structure of α-Bi(2)O(3) has been probed experimentally by thermoreflectance (TR) spectroscopy. The direct band gap was determined accurately to be 2.91 eV at 300 K. Temperaturedependent TR measurements of 30-300 K were carried out to evaluate temperature-energy shift and line-width broadening effect for the band edge of α-Bi(2)O(3) thin-film nanowires. Photoluminescence (PL) experiments at 30 and 300 K were carried out to identify band-edge emission as well as defect luminescence for the α-Bi(2)O(3) nanowires. On the basis of experimental analyses of TR and PL, optical characteristics of direct band edge of α-Bi(2)O(3) nanowires have thus been realized.

  3. Pure Cubic-Phase Hybrid Iodobismuthates AgBi2 I7 for Thin-Film Photovoltaics.

    PubMed

    Kim, Younghoon; Yang, Zhenyu; Jain, Ankit; Voznyy, Oleksandr; Kim, Gi-Hwan; Liu, Min; Quan, Li Na; García de Arquer, F Pelayo; Comin, Riccardo; Fan, James Z; Sargent, Edward H

    2016-08-08

    Bismuth-based hybrid perovskites are candidates for lead-free and air-stable photovoltaics, but poor surface morphologies and a high band-gap energy have previously limited these hybrid perovskites. A new materials processing strategy to produce enhanced bismuth-based thin-film photovoltaic absorbers by incorporation of monovalent silver cations into iodobismuthates is presented. Solution-processed AgBi2 I7 thin films are prepared by spin-coating silver and bismuth precursors dissolved in n-butylamine and annealing under an N2 atmosphere. X-ray diffraction analysis reveals the pure cubic structure (Fd3m) with lattice parameters of a=b=c=12.223 Å. The resultant AgBi2 I7 thin films exhibit dense and pinhole-free surface morphologies with grains ranging in size from 200-800 nm and a low band gap of 1.87 eV suitable for photovoltaic applications. Initial studies produce solar power conversion efficiencies of 1.22 % and excellent stability over at least 10 days under ambient conditions.

  4. Geomagnetic excitation of nutation

    NASA Astrophysics Data System (ADS)

    Ron, C.; Vondrák, J.

    2015-08-01

    We tested the hypothesis of Malkin (2013), who demonstrated that the observed changes of Free Core Nutation parameters (phase, amplitude) occur near the epochs of geomagnetic jerks. We found that if the numerical integration of Brzeziński broad-band Liouville equations of atmospheric/oceanic excitations is re-initialized at the epochs of geomagnetic jerks, the agreement between the integrated and observed celestial pole offsets is improved (Vondrák & Ron, 2014). Nevertheless, this approach assumes that the influence of geomagnetic jerks leads to a stepwise change in the position of celestial pole, which is physically not acceptable. Therefore we introduce a simple continuous excitation function that hypothetically describes the influence of geomagnetic jerks, and leads to rapid but continuous changes of pole position. The results of numerical integration of atmospheric/oceanic excitations and this newly introduced excitation are then compared with the observed celestial pole offsets, and prove that the agreement is improved significantly.

  5. Application of Thermodynamic Calculations to the Pyro-refining Process for Production of High Purity Bismuth

    NASA Astrophysics Data System (ADS)

    Mezbahul-Islam, Mohammad; Belanger, Frederic; Chartrand, Patrice; Jung, In-Ho; Coursol, Pascal

    2017-02-01

    The present work has been performed with the aim to optimize the existing process for the production of high purity bismuth (99.999 pct). A thermo-chemical database including most of the probable impurities of bismuth (Bi-X, X = Ag, Au, Al, Ca, Cu, Fe, Mg, Mn, Na, Ni, Pb, S, Sb, Sn, Si, Te, Zn) has been constructed to perform different thermodynamic calculations required for the refining process. Thermodynamic description for eight of the selected binaries, Bi-Ca, Cu, Mn, Ni, Pb, S, Sb, and Sn, has been given in the current paper. Using the current database, different thermodynamic calculations have been performed to explain the steps involved in the bismuth refining process.

  6. Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Sanner, Robert D.; Beck, Patrick R.; Swanberg, Erik L.; Tillotson, Thomas M.; Payne, Stephen A.; Hurlbut, Charles R.

    2015-04-01

    Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS(6Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%.

  7. Isotopic generator for bismuth-212 and lead-212 based on radium

    DOEpatents

    Hines, J.J.; Atcher, R.W.; Friedman, A.M.

    1985-01-30

    Disclosed are method and apparatus for providing radionuclides of bismuth-212 and lead-212. Thorium-228 and carrier solution starting material is input to a radiologically contained portion of an isotopic generator system, and radium-224 is separated from thorium-228 which is retained by a strongly basic anion exchange column. The separated radium-224 is transferred to an accessible, strongly acidic cationic exchange column. The cationic column retains the radium-224, and natural radioactive decay generates bismuth-212 and lead-212. The cationic exchange column can also be separated from the contained portion of the system and utilized without the extraordinary safety measures necessary in the contained portion. Furthermore, the cationic exchange column provides over a relatively long time period the short lived lead-212 and bismuth-212 radionuclides which are useful for a variety of medical therapies.

  8. Experimental investigation of the shock response of bismuth under one-dimensional shock-loading

    NASA Astrophysics Data System (ADS)

    Whiteman, Glenn; Millett, Jeremy; Appleby-Thomas, Gareth; Wood, David; Hameed, Amer

    2017-01-01

    Interest in the dynamic response of bismuth is largely derived from the existence of multiple phase transitions attainable with increasing pressure. In addition, its industrial use has grown in recent years (e.g. in solder as a replacement for lead), in part due to its relatively low toxicity. While some shock experiments have been conducted on bismuth they have largely concentrated on equation of state research at relatively low stresses. To the authors' knowledge the strength behaviour under shock is not prevalent in the literature. To this end, the low pressure response of bismuth targets has been experimentally investigated here using commercial stress gauges mounted in both longitudinal and lateral orientation with respect to the loading axis. Of particular note was the potential to observe the relatively low pressure phase transitions in the lateral stress response.

  9. Bismuth sulfide nanoflakes and nanorods as high performance photodetectors and photoelectrochemical cells

    NASA Astrophysics Data System (ADS)

    Chao, Junfeng; Xing, Shumin; Zhao, Yanchun; Gao, Suling; Song, Qinghua; Guo, Lixia; Wang, Di; Zhang, Tingliang

    2016-11-01

    Flake-like and rod-like bismuth sulfide nanostructures were synthesized via a facile polyol refluxing process. The rigid photodetectors based on both nanomaterials have the features of linear photocurrent characteristics and good sensitivity. Especially, the rigid bismuth sulfide nanoflakes photodetector has fast response time of 0.5 s and recovery time of 0.7 s. The flexible photodetectors were then fabricated on PET substrate, and this caused both the response time and the recovery time to increase by a factor of ∼2.5. Moreover, the photoelectrochemical (PEC) devices exhibited photosensitivity with the features of rapid response and recovery time, high on/off ratio and stable switching cycle performance. Our results imply that the two types of bismuth sulfide nanomaterials are prospective candidates for next generation photodetectors and optoelectronic switches.

  10. Preparation of bismuth-based nanosheets by ultrasound-assisted liquid laser ablation

    NASA Astrophysics Data System (ADS)

    Escobar-Alarcón, L.; Velarde Granados, E.; Solís-Casados, D. A.; Olea-Mejía, O.; Espinosa-Pesqueira, M.; Haro-Poniatowski, E.

    2016-04-01

    The preparation of bismuth nanosheets ablating a high purity Bi target immersed in water subjected to an ultrasound wave is reported. The effect of the laser fluence used for ablation on the size and shape of the nanostructures synthesized was investigated. The obtained results reveal the formation of nanosheets with square-like shape and sizes from approximately 140-543 nm. In comparison, experiments without the ultrasound field lead to the formation of quasi-spherical nanoparticles. The nanosheets were characterized by means of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis and Raman spectroscopies. The bismuth nanosheets, as deposited, are highly crystalline, and depending on the preparation conditions, the α or β phases of Bi2O3 are obtained. UV-Vis measurements show the typical band absorption characteristic of bismuth with nanometric size. Raman spectra confirm the formation of Bi2O3 nanostructures.

  11. Design of an Actinide Burning, Lead-Bismuth Cooled Reactor That Produces Low Cost Electricity

    SciTech Connect

    C. Davis; S. Herring; P. MacDonald; K. McCarthy; V. Shah; K. Weaver; J. Buongiorno; R. Ballinger; K. Doyoung; M. Driscoll; P. Hejzler; M. Kazimi; N. Todreas

    1999-07-01

    The purpose of this project is to investigate the suitability of lead-bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The goal is to identify and analyze the key technical issues in core neutronics, materials, thermal-hydraulics, fuels, and economics associated with the development of this reactor concept. The choice of lead-bismuth for the reactor coolant is an actinide burning fast reactor offers enhanced safety and reliability. The advantages of lead-bismuth over sodium as a coolant are related to the following material characteristics: chemical inertness with air and water; higher atomic number; lower vapor pressure at operating temperatures; and higher boiling temperature. Given the status of the field, it was agreed that the focus of this investigation in the first two years will be on the assessment of approaches to optimize core and plant arrangements in order to provide maximum safety and economic potential in this type of reactor.

  12. PROCESS USING BISMUTH PHOSPHATE AS A CARRIER PRECIPITATE FOR FISSION PRODUCTS AND PLUTONIUM VALUES

    DOEpatents

    Finzel, T.G.

    1959-03-10

    A process is described for separating plutonium from fission products carried therewith when plutonium in the reduced oxidation state is removed from a nitric acid solution of irradiated uranium by means of bismuth phosphate as a carrier precipitate. The bismuth phosphate carrier precipitate is dissolved by treatment with nitric acid and the plutonium therein is oxidized to the hexavalent oxidation state by means of potassium dichromate. Separation of the plutonium from the fission products is accomplished by again precipitating bismuth phosphate and removing the precipitate which now carries the fission products and a small percentage of the plutonium present. The amount of plutonium carried in this last step may be minimized by addition of sodium fluoride, so as to make the solution 0.03N in NaF, prior to the oxidation and prccipitation step.

  13. Coulomb excitation of radioactive nuclear beams in inverse kinematics

    SciTech Connect

    Zamfir, N.V. |||; Barton, C.J.; Brenner, D.S.; Casten, R.F. |; Gill, R.L.; Zilges, A. |

    1996-12-31

    Techniques for the measurement of B (E2:0{sub 1}{sup +} {r_arrow} 2{sub 1}{sup +}) values by Coulomb excitation of Radioactive Nuclear Beams in inverse kinematics are described. Using a thin, low Z target, the Coulomb excited beam nuclei will decay in flight downstream of the target. For long lifetimes (nanosecond range) these nuclei decay centimeters downstream of the target and for shorter lifetimes (picoseconds or less) they decay near the target. Corresponding to these two lifetime regimes two methods have been developed to measure {gamma} rays from the Coulomb excited nuclei: the lifetime method in which the lifetime of the excited state is deduced from the decay curve and the integral method in which the B(E2) value is extracted from the measured total Coulomb excitation cross section.

  14. Influence of bismuth on the charging ability of negative plates in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Lam, L. T.; Ceylan, H.; Haigh, N. P.; Manders, J. E.

    To examine the influence of bismuth on the charging ability of negative plates in lead-acid batteries, plates are made from three types of oxides: (i) leady oxide of high quality which contains virtually no bismuth (termed 'control oxide'); (ii) control oxide in which bismuth oxide is blended at bismuth levels from 0.01 to 0.12 wt.%; (iii) leady oxide produced from Pasminco VRLA Refined™ lead (0.05-0.06 wt.%Bi). An experimental tool—the 'conversion indicator'—is developed to assess the charging ability of the test negative plates when cycling under either zero percent state-of-charge (SoC)/full-charge or partial state-of-charge (PSoC) duty. Although the conversion indicator is not the true charging efficiency, the two parameters have a close relationship, namely, the higher the conversion indicator, the greater the charging efficiency. Little difference is found in the charging ability, irrespective of bismuth content and discharge rate, when the plates are subjected to zero percent SoC/full-charge duty; the conversion indicator lies in the range 81-84%. By contrast, there is a marked difference when the negative plates are subjected to PSoC duty, i.e. consecutive cycling through 90-60, 70-40, 80-40 and 90-40% SoC windows. Up to 0.06 wt.%Bi improves the charging ability, especially with a low and narrow PSoC window (40-70% SoC) of the type that will be experienced in 42 V powernet automobile and hybrid electric duties. To maximize this beneficial effect, bismuth must be distributed uniformly in the plates. This is best achieved by using VRLA Refined™ lead for oxide production.

  15. CONCENTRATION AND DECONTAMINATION OF SOLUTIONS CONTAINING PLUTONIUM VALUES BY BISMUTH PHOSPHATE CARRIER PRECIPITATION METHODS

    DOEpatents

    Seaborg, G.T.; Thompson, S.G.

    1960-08-23

    A process is given for isolating plutonium present in the tetravalent state in an aqueous solution together with fission products. First, the plutonium and fission products are coprecipitated on a bismuth phosphate carrier. The precipitate obtained is dissolved, and the plutonium in the solution is oxidized to the hexavalent state (with ceric nitrate, potassium dichromate, Pb/ sub 3/O/sub 4/, sodium bismuthate and/or potassium dichromate). Thereafter a carrier for fission products is added (bismuth phosphate, lanthanum fluoride, ceric phosphate, bismuth oxalate, thorium iodate, or thorium oxalate), and the fission-product precipitation can be repeated with one other of these carriers. After removal of the fission-product-containing precipitate or precipitates. the plutonium in the supernatant is reduced to the tetravalent state (with sulfur dioxide, hydrogen peroxide. or sodium nitrate), and a carrier for tetravalent plutonium is added (lanthanum fluoride, lanthanum hydroxide, lanthanum phosphate, ceric phosphate, thorium iodate, thorium oxalate, bismuth oxalate, or niobium pentoxide). The plutonium-containing precipitate is then dissolved in a relatively small volume of liquid so as to obtain a concentrated solution. Prior to dissolution, the bismuth phosphate precipitates first formed can be metathesized with a mixture of sodium hydroxide and potassium carbonate and plutonium-containing lanthanum fluorides with alkali-metal hydroxide. In the solutions formed from a plutonium-containing lanthanum fluoride carrier the plutonium can be selectively precipitated with a peroxide after the pH was adjusted preferably to a value of between 1 and 2. Various combinations of second, third, and fourth carriers are discussed.

  16. Bismuth Passivation Technique for High-Resolution X-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Chervenak, James; Hess, Larry

    2013-01-01

    The Athena-plus team requires X-ray sensors with energy resolution of better than one part in 3,000 at 6 keV X-rays. While bismuth is an excellent material for high X-ray stopping power and low heat capacity (for large signal when an X-ray is stopped by the absorber), oxidation of the bismuth surface can lead to electron traps and other effects that degrade the energy resolution. Bismuth oxide reduction and nitride passivation techniques analogous to those used in indium passivation are being applied in a new technique. The technique will enable improved energy resolution and resistance to aging in bismuth-absorber-coupled X-ray sensors. Elemental bismuth is lithographically integrated into X-ray detector circuits. It encounters several steps where the Bi oxidizes. The technology discussed here will remove oxide from the surface of the Bi and replace it with nitridized surface. Removal of the native oxide and passivating to prevent the growth of the oxide will improve detector performance and insulate the detector against future degradation from oxide growth. Placing the Bi coated sensor in a vacuum system, a reduction chemistry in a plasma (nitrogen/hydrogen (N2/H2) + argon) is used to remove the oxide and promote nitridization of the cleaned Bi surface. Once passivated, the Bi will perform as a better X-ray thermalizer since energy will not be trapped in the bismuth oxides on the surface. A simple additional step, which can be added at various stages of the current fabrication process, can then be applied to encapsulate the Bi film. After plasma passivation, the Bi can be capped with a non-diffusive layer of metal or dielectric. A non-superconducting layer is required such as tungsten or tungsten nitride (WNx).

  17. Thin Clouds

    Atmospheric Science Data Center

    2013-04-18

    ... one of a new generation of instruments flying aboard the NASA Earth Observing System's Terra satellite, views Earth with nine cameras ... of thin cirrus minutes after MISR imaged the cloud from space. At the same time, another NASA high-altitude jet, the WB-57, flew right ...

  18. Optical Properties of Crystalline Gallium Telluride and Bismuth Triiodide.

    NASA Astrophysics Data System (ADS)

    Wan, Jun Zuo

    Spontaneous photoluminescence (PL) and transmission measurements near the fundamental absorption edge of GaTe have been investigated under low-level laser excitation conditions in iodine transport vapour-grown high-quality GaTe crystals. The ground-state 1S triplet and singlet excitonic peaks are well resolved in optical continuous wave (cw) argon laser excited PL spectra, the triplet state lying ~1.6 meV lower in energy than the singlet state. Transmission spectra also indicate that the absorption corresponding to the n = 1 exciton is made up of two peaks, of which the higher-energy one is observed only for light polarized perpendicular to the b axis. We propose possible symmetries for the band gap edges of GaTe. We have resolved the n = 2 and n = 3 excited excitonic states under low level laser excitation conditions. We assign two weak lines at energies ~1.7757 eV and ~1.7735 eV in the cw excited PL spectra to bound excitons and a broad band at ~1.73 eV with a full width at half maximum (FWHM) of ~30 meV to donor-acceptor pair recombinations. We have measured that the radiative lifetime of free excitons is less than 100 ps at a photo -excited e-h pair density of ~10 ^{15} cm^ {-3} and crystal temperature of 8.7 K. We have also estimated radiative lifetimes for bound excitons. We find that over the range of 5 to 25 K, the temperature variation of the excitonic emission linewidth and peak energy comes mainly from exciton-acoustic phonon interactions via the deformation potential. We have found some indications for exciton condensations in GaTe at T = 6 K under higher excitation conditions. Finally, we have also studied single crystals of BiI_3, another layered material, using optical transmission measurement.

  19. Terahertz-range spontaneous emission under the optical excitation of donors in uniaxially stressed bulk silicon and SiGe/Si heterostructures

    SciTech Connect

    Zhukavin, R. Kh. Kovalevsky, K. A.; Orlov, M. L.; Tsyplenkov, V. V.; Bekin, N. A.; Yablonskiy, A. N.; Yunin, P. A.; Pavlov, S. G.; Abrosimov, N. V.; Hübers, H.-W.; Radamson, H. H.; Shastin, V. N.

    2015-01-15

    The results of measurements of the total terahertz-range photoluminescence of Group-V donors (phosphorus, antimony, bismuth, arsenic) in bulk silicon and SiGe/Si heterostructures depending on the excitation intensity are presented. The signal of bulk silicon was also measured as a function of uniaxial stress. The results of measurement of the dependence of the spontaneous emission intensity on the uniaxial stress is in rather good agreement with theoretical calculations of the relaxation times of excited states of donors in bulk silicon. Comparative measurements of the spontaneous emission from various strained heterostructures showed that the photoluminescence signal is caused by donor-doped silicon regions.

  20. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode.

    PubMed

    Zhou, Bin; Qu, Jiuhui; Zhao, Xu; Liu, Huijuan

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating. After annealation at 400, 500, and 600 degrees C, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry. The BiVO4 particles on the ITO glass surface had a monoclinic structure. The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV. In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichlorophenol and Bisphenol A degradation under visible light irradiation (lambda > 420 nm). Over 90% of the two organic pollutants were removed in 5 hr. A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  1. How to Effectively Use Bismuth Quadruple Therapy: The Good, the Bad, and the Ugly.

    PubMed

    Graham, David Y; Lee, Sun-Young

    2015-09-01

    Bismuth triple therapy was the first effective Helicobacter pylori eradication therapy. The addition of a proton pump inhibitor helped overcome metronidazole resistance. Its primary indication is penicillin allergy or when clarithromycin and metronidazole resistance are both common. Resistance to the primary first-line therapy have centered on complexity and difficulties with compliance. Understanding regional differences in effectiveness remains unexplained because of the lack of studies including susceptibility testing and adherence data. We discuss regimen variations including substitutions of doxycycline, amoxicillin, and twice a day therapy and provide suggestions regarding what is needed to rationally and effectively use bismuth quadruple therapy.

  2. Atomic Environment Changes Induced by Iron Addition to Gallium Bismuthate Glasses

    NASA Astrophysics Data System (ADS)

    Simon, V.; BarzǍ, L.; Simon, S.; ChiuzbǍIAN, S. G.; Neumann, M.

    Atomic environment of xFe2O3·(80-x)Bi2O3·20Ga2O3 heavy glasses (0≤x≤20 mol%) was investigated with respect to electronic structure of the samples. Data obtained from Bi 4f, Ga 2p, Fe 2p, and O 1s core-level photoelectron spectra indicate changes in the local order on the account of partial substitution of bismuth by iron. The bismuth cations behave essentially as network formers while the iron and gallium ones acts as network modifiers. The number of nonbridging oxygens depends on Fe2O3 content.

  3. Healing and recurrence of duodenal ulcer after treatment with tripotassium dicitrato bismuthate (TDB) tablets or cimetidine.

    PubMed

    Hamilton, I; O'Connor, H J; Wood, N C; Bradbury, I; Axon, A T

    1986-01-01

    Eighty patients with duodenal ulcer were randomly allocated to treatment with tripotassium dicitrato bismuthate (TDB) tablets or cimetidine. Ulcers healed in 78% of patients treated with TDB and in 74% treated with cimetidine, supporting previous observations that the efficacy of these two agents is similar. Duodenal ulcer recurred in 43% of patients in the 12 months after treatment with TDB and in 78% of patients treated with cimetidine, with a significantly greater incidence of recurrence 6-12 months after cimetidine treatment. Tripotassium dicitrato bismuthate tablets may be preferable to cimetidine in the initial management of duodenal ulcer, because they offer a smaller likelihood of recurrence in the 12 months after successful treatment.

  4. Fabrication of Nanovoid-Imbedded Bismuth Telluride with Low Dimensional System

    NASA Technical Reports Server (NTRS)

    Chu, Sang-Hyon (Inventor); Choi, Sang H. (Inventor); Kim, Jae-Woo (Inventor); Park, Yeonjoon (Inventor); Elliott, James R. (Inventor); King, Glen C. (Inventor); Stoakley, Diane M. (Inventor)

    2013-01-01

    A new fabrication method for nanovoids-imbedded bismuth telluride (Bi--Te) material with low dimensional (quantum-dots, quantum-wires, or quantum-wells) structure was conceived during the development of advanced thermoelectric (TE) materials. Bismuth telluride is currently the best-known candidate material for solid-state TE cooling devices because it possesses the highest TE figure of merit at room temperature. The innovative process described here allows nanometer-scale voids to be incorporated in Bi--Te material. The final nanovoid structure such as void size, size distribution, void location, etc. can be also controlled under various process conditions.

  5. Decay of photoinduced oscillations of the optical reflection coefficient of bismuth

    SciTech Connect

    Semenov, A. L.

    2013-07-15

    A model describing the decay of photoinduced oscillations of the optical reflection coefficient R of bismuth is constructed, taking the crystal lattice anharmonicity into account. The decay time of oscillations of R is calculated as a function of the energy density of a laser pulse. The results of calculations explain the experimental data on the anomalously strong decay of oscillations of the optical reflection coefficient of bismuth (the decay time decreases by more than an order of magnitude with an increase in the laser pulse energy density from 0 to 4 mJ/cm{sup 2})

  6. Metalloantibiotics: synthesis, characterization and antimicrobial evaluation of bismuth-fluoroquinolone complexes against Helicobacter pylori.

    PubMed

    Shaikh, Anwar R; Giridhar, Rajani; Megraud, Francis; Yadav, Mange Ram

    2009-09-01

    Novel organometallic compounds have been prepared by complexing the fluoroquinolones, norfloxacin, ofloxacin, ciprofloxacin, sparfloxacin, lomefloxacin, pefloxacin and gatifloxacin, with bismuth. The complexes were characterized by UV, IR, atomic absorption spectroscopy, elemental analysis, differential scanning calorimetry, thermogravimetric analysis and mass spectrometry. Their antibacterial potential against Helicobacter pylori and other microorganisms was investigated. These compounds were found to possess strong activity against Helicobacter pylori with a minimum inhibitory concentration of 0.5 mg L-1. They also exhibited moderate activity against Escherichia coli, Staphylococcus aureus, Bacillus pumilus and Staphylococcus epidermidis. These bismuth-fluoroquinolone complexes have the potential to be developed as drugs against H. pylori related ailments.

  7. Numerical study: Iron corrosion-resistance in lead-bismuth eutectic coolant by molecular dynamics method

    SciTech Connect

    Arkundato, Artoto; Su'ud, Zaki; Abdullah, Mikrajuddin; Widayani,; Celino, Massimo

    2012-06-06

    In this present work, we report numerical results of iron (cladding) corrosion study in interaction with lead-bismuth eutectic coolant of advanced nuclear reactors. The goal of this work is to study how the oxygen can be used to reduce the corrosion rate of cladding. The molecular dynamics method was applied to simulate corrosion process. By evaluating the diffusion coefficients, RDF functions, MSD curves of the iron and also observed the crystal structure of iron before and after oxygen injection to the coolant then we concluded that a significant and effective reduction can be achieved by issuing about 2% number of oxygen atoms to lead-bismuth eutectic coolant.

  8. Enhancement of Er optical efficiency through bismuth sensitization in yttrium oxide

    SciTech Connect

    Scarangella, Adriana; Reitano, Riccardo; Franzò, Giorgia; Miritello, Maria; Priolo, Francesco

    2015-07-27

    The process of energy transfer (ET) between optically active ions has been widely studied to improve the optical efficiency of a system for different applications, from lighting and photovoltaics to silicon microphotonics. In this work, we report the influence of Bi on the Er optical emission in erbium-yttrium oxide thin films synthesized by magnetron co-sputtering. We demonstrate that this host permits to well dissolve Er and Bi ions, avoiding their clustering, and thus to stabilize the optically active Er{sup 3+} and Bi{sup 3+} valence states. In addition, we establish the ET occurrence from Bi{sup 3+} to Er{sup 3+} by the observed Bi{sup 3+} PL emission decrease and the simultaneous Er{sup 3+} photoluminescence (PL) emission increase. This was further confirmed by the coincidence of the Er{sup 3+} and Bi{sup 3+} excitation bands, analyzed by PL excitation spectroscopy. By increasing the Bi content of two orders of magnitude inside the host, though the occurrence of Bi-Bi interactions becomes deleterious for Bi{sup 3+} optical efficiency, the ET process between Bi{sup 3+} and Er{sup 3+} is still prevalent. We estimate ET efficiency of 70% for the optimized Bi:Er ratio equal to 1:3. Moreover, we have demonstrated to enhance the Er{sup 3+} effective excitation cross section by more than three orders of magnitude with respect to the direct one, estimating a value of 5.3 × 10{sup −18} cm{sup 2}, similar to the expected Bi{sup 3+} excitation cross section. This value is one of the highest obtained for Er in Si compatible hosts. These results make this material very promising as an efficient emitter for Si-compatible photonics devices.

  9. Excitation and Characterization of Chladni Plate Patterns

    NASA Astrophysics Data System (ADS)

    Bourke, Shannon; Behringer, Ernest

    2011-04-01

    When a thin metal plate with a small amount of sand on it is made to vibrate, aesthetically pleasing sand patterns can form along the nodal lines of the plate. These symmetric patterns are called Chladni Patterns. Students taking PHY 101 Physical Science in the Arts at Eastern Michigan University create these patterns by pulling a violin bow across the edge of a plate, or by using a mechanical oscillator to drive the center of a plate. These two methods only allow a small subset of all possible points on the plate to be excited. We designed and built an electronic device that allows its user to excite the plate at any point. We present patterns created with this electronic device and other methods, and describe ways to model the observed patterns.

  10. Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles

    SciTech Connect

    Biasotto, G.; Simoes, A.Z.; Foschini, C.R.; Zaghete, M.A.; Varela, J.A.; Longo, E.

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer BiFeO{sub 3} (BFO) nanoparticles were grown by hydrothermal microwave method (HTMW). Black-Right-Pointing-Pointer The soaking time is effective in improving phase formation. Black-Right-Pointing-Pointer Rietveld refinement reveals an orthorhombic structure. Black-Right-Pointing-Pointer The observed magnetism of the BFO crystallites is a consequence of particle size. Black-Right-Pointing-Pointer The HTMW is a genuine technique for low temperatures and short times of synthesis. -- Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline bismuth ferrite (BiFeO{sub 3}) nanoparticles (BFO) in the temperature of 180 Degree-Sign C with times ranging from 5 min to 1 h. BFO nanoparticles were characterized by means of X-ray analyses, FT-IR, Raman spectroscopy, TG-DTA and FE-SEM. X-ray diffraction results indicated that longer soaking time was benefit to refraining the formation of any impurity phases and growing BFO crystallites into almost single-phase perovskites. Typical FT-IR spectra for BFO nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH{sup -} groups, commonly found in materials obtained by HTMW process. Compared with the conventional solid-state reaction process, submicron BFO crystallites with better homogeneity could be produced at the temperature as low as 180 Degree-Sign C. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain BFO nanoparticles in the temperature of 180 Degree-Sign C for 1 h.

  11. Photocatalytic activities of various pentavalent bismuthates under visible light irradiation

    SciTech Connect

    Takei, Takahiro; Haramoto, Rie; Dong, Qiang; Kumada, Nobuhiro; Yonesaki, Yoshinori; Kinomura, Nobukazu; Mano, Takayuki; Nishimoto, Shunsuke; Kameshima, Yoshikazu; Miyake, Michihiro

    2011-08-15

    LiBiO{sub 3}, NaBiO{sub 3}, MgBi{sub 2}O{sub 6}, KBiO{sub 3}, ZnBi{sub 2}O{sub 6}, SrBi{sub 2}O{sub 6}, AgBiO{sub 3}, BaBi{sub 2}O{sub 6} and PbBi{sub 2}O{sub 6} were synthesized by various processes such as hydrothermal treatment, heating and so on. These materials were examined for their photocatalytic activities in the decolorization of methylene blue and decomposition of phenol under visible light irradiation. For methylene blue decolorization, the presence of KBiO{sub 3} resulted in complete decoloration within 5 min. For phenol decomposition, NaBiO{sub 3} showed the highest activity, while LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} possessed almost comparable decomposition rates. Their decomposition rates were apparently higher than that by anatase (P25) under UV irradiation. - Graphical abstract: Nine pentavalent bismuthates were synthesized and were examined for their photocatalytic activities by decomposition of phenol under visible light irradiation. NaBiO{sub 3}, LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} indicated faster decomposition rate than that of anatase (P25) under UV-vis light irradiation. Highlights: > KBiO{sub 3} decolorize methylene blue aqueous solution immediately within 5 min. > NaBiO{sub 3}, LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} indicated high decomposition rate of phenol. > The d electron of Zn, Ag and Pb form broad conduction band. > The broad conduction band poses to diminish photocatalytic activity.

  12. Cyanido Antimonate(III) and Bismuthate(III) Anions.

    PubMed

    Arlt, Sören; Harloff, Jörg; Schulz, Axel; Stoffers, Alrik; Villinger, Alexander

    2016-12-05

    The reaction of in situ generated E(CN)3 (E = Sb, Bi) with different amounts of [Ph4P]CN and [PPN]CN ([PPN](+) = [Ph3P-N-PPh3](+)) was studied, affording salts bearing the novel ions [E(CN)5](2-), [Bi2(CN)11](5-), and [Bi(CN)6](3-). The valence lone pair of electrons on the central atom of antimony and bismuth(III) compounds can be either sterically active in an unsymmetric fashion (three shorter bonds + x longer bonds) or symmetric (with rather long averaged bonds). In the presence of weakly coordinating cations (e.g., [Ph4P](+) and [PPN](+)), the solid-state structures of salts with [E(CN)5](2-) anions contain well-separated cations and monomeric anions, which display a sterically active lone pair and a monomeric square-based pyramidal (pseudo-octahedral) structure. The [Bi(CN)5·MeCN](2-) acetonitrile adduct ion exhibits a strongly distorted octahedral structure, which is better understood as a [5 + 1] coordination. The intriguing [Ph4P]6[Bi2(CN)11]CN salt consists of separated cations and anions as well as well-separated [Bi2(CN)11](5-) and CN(-) ions. The structure of the molecular [Bi2(CN)11](5-) ion can be described as two square-based-pyramidal [Bi(CN)5](2-) fragments connected by a disordered bridging CN(-) ion, thereby leading to a distorted-octahedral environment around the two Bi centers. Here the steric effect of the lone pair is much less pronounced but still present.

  13. An Inexpensive Bismuth-Petrolatum Dressing for Treatment of Burns

    PubMed Central

    Chattopadhyay, Arhana; Chang, Kathleen; Nguyen, Khoa; Galvez, Michael G.; Legrand, Anais; Davis, Christopher; McGoldrick, Rory; Long, Chao; Pham, Hung

    2016-01-01

    Background: Xeroform remains the current standard for treating superficial partial-thickness burns but can be prohibitively expensive in developing countries with prevalent burn injuries. This study (1) describes the production of an alternative low-cost dressing and (2) compares the alternative dressing and Xeroform using the metrics of cost-effectiveness, antimicrobial activity, and biocompatibility in vitro, and wound healing in vivo. Methods: To produce the alternative dressing, 3% bismuth tribromophenate powder was combined with petroleum jelly by hand and applied to Kerlix gauze. To assess cost-effectiveness, the unit costs of Xeroform and components of the alternative dressing were compared. To assess antimicrobial properties, the dressings were placed on agar plated with Escherichia coli and the Kirby-Bauer assay performed. To assess biocompatibility, the dressings were incubated with human dermal fibroblasts and cells stained with methylene blue. To assess in vivo wound healing, dressings were applied to excisional wounds on rats and the rate of re-epithelialization calculated. Results: The alternative dressing costs 34% of the least expensive brand of Xeroform. Antimicrobial assays showed that both dressings had similar bacteriostatic effects. Biocompatibility assays showed that there was no statistical difference (P < 0.05) in the cytotoxicity of Xeroform, alternative dressing, and Kerlix gauze. Finally, the in vivo healing model showed no statistical difference (P < 0.05) in mean re-epithelialization time between Xeroform (13.0 ± 1.6 days) and alternative dressing (13.5 ± 1.0 days). Conclusions: Xeroform is biocompatible, reduces infection, and enhances healing of burn wounds by preventing desiccation and mechanical trauma. Handmade petrolatum gauze may be a low-cost replacement for Xeroform. Future studies will focus on clinical trials in burn units. PMID:27482485

  14. Electrical properties of niobium doped barium bismuth-titanate ceramics

    SciTech Connect

    Bobić, J.D.; Vijatović Petrović, M.M.; Banys, J.; Stojanović, B.D.

    2012-08-15

    Highlights: ► Pure and doped BaBi{sub 4}Ti{sub 4}O{sub 15} were prepared via the solid-state reaction method. ► The grain size was suppressed in Nb-doped samples. ► The diffuseness of the dielectric peak increased with dopant concentration. ► Niobium affected on relaxor behavior of barium bismuth titanate ceramics. ► The conductivity change was noticed in doped samples. -- Abstract: BaBi{sub 4}Ti{sub 4–5/4x}Nb{sub x}O{sub 15} (BBNTx, x = 0, 0.05, 0.15, 0.30) ceramics have been prepared by solid state method. XRD data indicate the formation of single-phase-layered perovskites for all compositions. SEM micrographs suggest that the grain size decreases with Nb doping. The effect of niobium doping on the dielectric and relaxor behavior of BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics was investigated in a wide range of temperatures (20–777 °C) and frequencies (1.21 kHz to 1 MHz). Nb doping influences T{sub c} decrease as well as the decrease of dielectric permittivity at Curie temperature. At room temperature, undoped BaBi{sub 4}Ti{sub 4}O{sub 15} exhibits dielectric constant of ∼204 at 100 kHz, that slightly increases with Nb doping. The conductivity of BBNT5 ceramics is found to be lower than that of other investigated compositions. The value of activation energy of σ{sub DC} was found to be 0.89 eV, 1.01 eV, 0.93 eV and 0.71 eV for BBT, BBNT5, BBNT15 and BBNT30, respectively.

  15. Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth

    PubMed Central

    Bentley, Ronald; Chasteen, Thomas G.

    2002-01-01

    A significant 19th century public health problem was that the inhabitants of many houses containing wallpaper decorated with green arsenical pigments experienced illness and death. The problem was caused by certain fungi that grew in the presence of inorganic arsenic to form a toxic, garlic-odored gas. The garlic odor was actually put to use in a very delicate microbiological test for arsenic. In 1933, the gas was shown to be trimethylarsine. It was not until 1971 that arsenic methylation by bacteria was demonstrated. Further research in biomethylation has been facilitated by the development of delicate techniques for the determination of arsenic species. As described in this review, many microorganisms (bacteria, fungi, and yeasts) and animals are now known to biomethylate arsenic, forming both volatile (e.g., methylarsines) and nonvolatile (e.g., methylarsonic acid and dimethylarsinic acid) compounds. The enzymatic mechanisms for this biomethylation are discussed. The microbial conversion of sodium arsenate to trimethylarsine proceeds by alternate reduction and methylation steps, with S-adenosylmethionine as the usual methyl donor. Thiols have important roles in the reductions. In anaerobic bacteria, methylcobalamin may be the donor. The other metalloid elements of the periodic table group 15, antimony and bismuth, also undergo biomethylation to some extent. Trimethylstibine formation by microorganisms is now well established, but this process apparently does not occur in animals. Formation of trimethylbismuth by microorganisms has been reported in a few cases. Microbial methylation plays important roles in the biogeochemical cycling of these metalloid elements and possibly in their detoxification. The wheel has come full circle, and public health considerations are again important. PMID:12040126

  16. Synthesis and characterization of nanocrystalline MoBi2Te5 thin films for photoelectrode applications

    NASA Astrophysics Data System (ADS)

    Salunkhe, M. M.; Kharade, R. R.; Mane, R. M.; Bhosale, P. N.

    2012-10-01

    Molybdenum bismuth telluride thin films have been prepared on clean glass substrate using arrested precipitation technique which is based on self-organized growth process. As deposited MoBi2Te5 thin films were dried in constant temperature oven at 110°C and further characterized for their optical, structural, morphological, compositional, and electrical analysis. Optical absorption spectra recorded in the wavelength range 300-800 nm showed band gap (E g) 1.44 eV. X-ray diffraction pattern and scanning electron microscopic images showed that MoBi2Te5 thin films are granular, nanocrystalline having rhombohedral structure. The compositional analysis showed close agreements in theoretical and experimental atomic percentages of Mo4+, Bi3+, and Te2- suggest that chemical formula MoBi2Te5 assigned to as deposited molybdenum bismuth telluride new material is confirmed. The electrical conductivity and thermoelectric power measurement showed that the films are semiconducting with n-type conduction. The fill factor and conversion efficiency was characterized by photoelectrochemical (PEC) technique. In this article, we report the optostructural, morphological, compositional, and electrical characteristics of nanocrystalline MoBi2Te5 thin films to check its suitability as photoelectrode in PEC cell.

  17. Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells.

    PubMed

    Hong, Yifan; Lai, Yau-Tsz; Chan, Godfrey Chi-Fung; Sun, Hongzhe

    2015-03-17

    Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown. For the first time (to our knowledge), we systematically and quantitatively studied the metabolism of bismuth in human cells. Our data demonstrated that over 90% of bismuth was passively absorbed, conjugated to glutathione, and transported into vesicles by MRP transporter. Mathematical modeling of the system reveals an interesting phenomenon. Passively absorbed bismuth consumes intracellular glutathione, which therefore activates de novo biosynthesis of glutathione. Reciprocally, sequestration by glutathione facilitates the passive uptake of bismuth and thus completes a self-sustaining positive feedback circle. This mechanism robustly removes bismuth from both intra- and extracellular space, protecting critical systems of human body from acute toxicity. It elucidates the selectivity of bismuth drugs between human and pathogens that lack of glutathione, such as Helicobacter pylori, opening new horizons for further drug development.

  18. Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells

    PubMed Central

    Hong, Yifan; Lai, Yau-Tsz; Chan, Godfrey Chi-Fung; Sun, Hongzhe

    2015-01-01

    Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown. For the first time (to our knowledge), we systematically and quantitatively studied the metabolism of bismuth in human cells. Our data demonstrated that over 90% of bismuth was passively absorbed, conjugated to glutathione, and transported into vesicles by MRP transporter. Mathematical modeling of the system reveals an interesting phenomenon. Passively absorbed bismuth consumes intracellular glutathione, which therefore activates de novo biosynthesis of glutathione. Reciprocally, sequestration by glutathione facilitates the passive uptake of bismuth and thus completes a self-sustaining positive feedback circle. This mechanism robustly removes bismuth from both intra- and extracellular space, protecting critical systems of human body from acute toxicity. It elucidates the selectivity of bismuth drugs between human and pathogens that lack of glutathione, such as Helicobacter pylori, opening new horizons for further drug development. PMID:25737551

  19. Extended two-temperature model for ultrafast thermal response of band gap materials upon impulsive optical excitation

    SciTech Connect

    Shin, Taeho; Teitelbaum, Samuel W.; Wolfson, Johanna; Nelson, Keith A.; Kandyla, Maria

    2015-11-21

    Thermal modeling and numerical simulations have been performed to describe the ultrafast thermal response of band gap materials upon optical excitation. A model was established by extending the conventional two-temperature model that is adequate for metals, but not for semiconductors. It considers the time- and space-dependent density of electrons photoexcited to the conduction band and accordingly allows a more accurate description of the transient thermal equilibration between the hot electrons and lattice. Ultrafast thermal behaviors of bismuth, as a model system, were demonstrated using the extended two-temperature model with a view to elucidating the thermal effects of excitation laser pulse fluence, electron diffusivity, electron-hole recombination kinetics, and electron-phonon interactions, focusing on high-density excitation.

  20. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, İ. Afşin

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.