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Sample records for bismuth tellurides

  1. Phase transition of bismuth telluride thin films grown by MBE

    DEFF Research Database (Denmark)

    Fülöp, Attila; Song, Yuxin; Charpentier, Sophie

    2014-01-01

    A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formation...

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

    Energy Technology Data Exchange (ETDEWEB)

    Molli, Muralikrishna, E-mail: muralikrishnamolli@sssihl.edu.in [Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam-515 134 (India); Parola, Sowmendran; Avinash Chunduri, L.A.; Aditha, Saikiran; Sai Muthukumar, V; Mimani Rattan, Tanu; Kamisetti, Venkataramaniah [Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam-515 134 (India)

    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.

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

    Science.gov (United States)

    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.

  4. Process dependent thermoelectric properties of EDTA assisted bismuth telluride

    Science.gov (United States)

    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.

  5. Shock-Wave Consolidation of Nanostructured Bismuth Telluride Powders

    Science.gov (United States)

    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.

  6. Electrodeposition of bismuth telluride thermoelectric films from a nonaqueous electrolyte using ethylene glycol

    NARCIS (Netherlands)

    Nguyen, H.P.; Wu, M.; Su, J.; Vullers, R.J.M.; Vereecken, P.M.; Fransaer, J.

    2012-01-01

    Ethylene glycol was studied as an electrolyte for the electrodeposition of thermoelectric bismuth telluride films by cyclic voltammetry, rotating ring disk electrode and electrochemical quartz crystal microbalance (EQCM). The reduction of both Bi3+ and Te4+ ions proceeds in one step without the form

  7. Structural Engineering of Vacancy Defected Bismuth Tellurides for Thermo-electric Applications

    Science.gov (United States)

    Termentzidis, K.; Pokropivny, A.; Xiong, S.-Y.; Chumakov, Y.; Cortona, P.; Volz, S.

    2012-10-01

    Molecular Dynamics and ab-initio simulations are used to find the most stable stoichiometries of Bismuth Tellurides with vacancy defects. The interest is to decrease the thermal conductivity of these compounds a key point to achieve high figure of merits. A reduction of 70% of the thermal conductivity is observed with Te vacancies of only 5%.

  8. Low-temperature, template-free synthesis of single-crystal bismuth telluride nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Purkayastha, A. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Lupo, F. [Max Planck Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Kim, S.; Borca-Tasciuc, T. [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Ramanath, G. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Max Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2006-02-17

    Synthesis of single-crystal bismuth telluride nanorods is reported by using a low-temperature, template-free approach. Films of thioglycolic acid functionalized nanorods doped with sulfur exhibit n-type behavior with a high Seebeck coefficient, holding promise for thermoelectric device applications. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  9. Structural Engineering of Vacancy Defected Bismuth Tellurides for Thermo-electric Applications

    Directory of Open Access Journals (Sweden)

    Chumakov Y.

    2012-10-01

    Full Text Available Molecular Dynamics and ab-initio simulations are used to find the most stable stoichiometries of Bismuth Tellurides with vacancy defects. The interest is to decrease the thermal conductivity of these compounds a key point to achieve high figure of merits. A reduction of 70% of the thermal conductivity is observed with Te vacancies of only 5%.

  10. Ab initio lattice dynamics and thermochemistry of layered bismuth telluride (Bi2Te3)

    Science.gov (United States)

    Zurhelle, Alexander F.; Deringer, Volker L.; Stoffel, Ralf P.; Dronskowski, Richard

    2016-03-01

    We present density-functional theory calculations of the lattice dynamics of bismuth telluride, yielding force constants, mean-square displacements and partial densities of phonon states which corroborate and complement previous nuclear inelastic scattering experiments. From these data, we derive an element- and energy-resolved view of the vibrational anharmonicity, quantified by the macroscopic Grüneisen parameter γ which results in 1.56. Finally, we calculate thermochemical properties in the quasiharmonic approximation, especially the heat capacity at constant pressure and the enthalpy of formation for bismuth telluride; the latter arrives at ▵H f (Bi2Te3)  =  -102 kJ mol-1 at 298 K.

  11. Facile production of thermoelectric bismuth telluride thick films in the presence of polyvinyl alcohol.

    Science.gov (United States)

    Lei, C; Burton, M R; Nandhakumar, I S

    2016-06-01

    Bismuth telluride is currently the best performing thermoelectric material for room temperature operations in commercial thermoelectric devices. We report the reproducible and facile production of 600 micron thick bismuth telluride (Bi2Te3) layers by low cost and room temperature pulsed and potentiostatic electrodeposition from a solution containing bismuth and tellurium dioxide in 2 M nitric acid onto nickel in the presence of polyvinyl alcohol (PVA). This was added to the electrolyte to promote thick layer formation and its effect on the structure, morphology and composition of the electrodeposits was investigated by SEM and EDX. Well adherent, uniform, compact and stoichiometric n-type Bi2Te3 films with a high Seebeck coefficient of up to -200 μV K(-1) and a high electrical conductivity of up to 400 S cm(-1) resulting in a power factor of 1.6 × 10(-3) W m(-1) K(-2) at film growth rates of 100 μm h(-1) for potentiostatic electrodeposition were obtained. The films also exhibited a well defined hexagonal structure as determined by XRD.

  12. Feasibility of preparing patterned molybdenum coatings on bismuth telluride thermoelectric modules.

    Energy Technology Data Exchange (ETDEWEB)

    Sarobol, Pylin; Hall, Aaron Christopher; Miller, Stephen Samuel; Knight, Marlene E.; LePage, William S.; Sobczak, Catherine Elizabeth.; Wesolowski, Daniel Edward

    2013-09-01

    Molybdenum electrical interconnects for thermoelectric modules were produced by air plasma spraying a 30%CE%BCm size molybdenum powder through a laser-cut Kapton tape mask. Initial feasibility demonstrations showed that the molybdenum coating exhibited excellent feature and spacing retention (~170%CE%BCm), adhered to bismuth-telluride, and exhibited electrical conductivity appropriate for use as a thermoelectric module interconnect. A design of experiments approach was used to optimize air plasma spray process conditions to produce a molybdenum coating with low electrical resistivity. Finally, a molybdenum coating was successfully produced on a fullscale thermoelectric module. After the addition of a final titanium/gold layer deposited on top of the molybdenum coating, the full scale module exhibited an electrical resistivity of 128%CE%A9, approaching the theoretical resistivity value for the 6mm module leg of 112%CE%A9. Importantly, air plasma sprayed molybdenum did not show significant chemical reaction with bismuth-telluride substrate at the coating/substrate interface. The molybdenum coating microstructure consisted of lamellar splats containing columnar grains. Air plasma sprayed molybdenum embedded deeply (several microns) into the bismuth-telluride substrate, leading to good adhesion between the coating and the substrate. Clusters of round pores (and cracks radiating from the pores) were found immediately beneath the molybdenum coating. These pores are believed to result from tellurium vaporization during the spray process where the molten molybdenum droplets (2623%C2%B0C) transferred their heat of solidification to the substrate at the moment of impact. Substrate cooling during the molybdenum deposition process was recommended to mitigate tellurium vaporization in future studies.

  13. Electrowetting on dielectric-actuation of microdroplets of aqueous bismuth telluride nanoparticle suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Dash, Raj K [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Borca-Tasciuc, T [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Purkayastha, A [Materials Science and Engineering Department, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Ramanath, G [Materials Science and Engineering Department, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States)

    2007-11-28

    This work reports the actuation of droplets of nanofluid by the electrowetting on dielectric (EWOD) effect. The nanofluid is comprised of an aqueous (deionized water) suspension of 3 nm diameter bismuth telluride nanoparticles capped with thioglycolic acid (TGA). Microdroplets of nanofluid are cast on Si(001) wafers coated with 100 nm thick layers of silicon dioxide and AF Teflon. Applying an electric field between the substrate and an electrode immersed in the nanofluid droplet results in a strong change in the contact angle from 110{sup 0} to 84{sup 0} for a 0-60 V voltage range. The droplets of nanofluid exhibit enhanced stability and absence of contact angle saturation in the tested voltage range when compared with droplets of aqueous solutions of 0.01 M Na{sub 2}SO{sub 4} or thioglycolic acid in deionized water. We propose that ion generation due to capping-agent desorption is a key factor determining the EWOD effect in the bismuth telluride nanofluid along with the nanoparticle contribution to charge transport. Our results open up new vistas for using nanofluids for microscale actuator device applications.

  14. Preparation of bismuth telluride thin film by electrochemical atomic layer epitaxy(ECALE)

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Junyou; GAO Xianhui; HOU Jie; BAO Siqian; FAN Xian

    2007-01-01

    Thin-layer electrochemical studies of the underpotential deposition(UPD)of Bi and Te on cold rolled silver substrate have been performed.The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and Bi UPD on Te-covered Ag fitted UPD dynamics mechanism.A thin film of bismuth telluride was formed by alternately depositing Te and Bi via an automated flow deposition system.X-ray diffraction indicated the deposits of Bi2Te3.Energy Dispersive X-ray Detector quantitative analysis gave a 2:3 stoichiornetric ratio of Bi to Te,which was consistent with X-ray Diffraction results.Electron probe microanalysis of the deposits showed a network structure that results from the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit.

  15. Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

    KAUST Repository

    Aktakka, Ethem Erkan

    2013-10-01

    This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm2-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μ W from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi2Te3 and Sb2Te3 thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers. © 2013 IEEE.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Airul Azha Abd [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Technology Park Malaysia, Malaysia Institute of Microelectronics and System, Kuala Lumpur (Malaysia); Umar, Akrajas Ali; Salleh, Muhamad Mat [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Chen, Xiaomei [Jimei University, College of Food and Biological Engineering, Jimei, Xiamen (China); Oyama, Munetaka [Kyoto University, Graduate School of Engineering, Nishikyoku, Kyoto (Japan)

    2016-02-15

    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{sup -1} K{sup -2}) and 10 μV/K (and 19.5 μW m{sup -1} K{sup -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

  17. Atomic ordering in cubic bismuth telluride alloy phases at high pressure

    Science.gov (United States)

    Loa, I.; Bos, J.-W. G.; Downie, R. A.; Syassen, K.

    2016-06-01

    Pressure-induced transitions from ordered intermetallic phases to substitutional alloys to semi-ordered phases were studied in a series of bismuth tellurides. By using angle-dispersive x-ray diffraction, the compounds Bi4Te5 , BiTe, and Bi2Te were observed to form alloys with the disordered body-centered cubic (bcc) crystal structure upon compression to above 14-19 GPa at room temperature. The BiTe and Bi2Te alloys and the previously discovered high-pressure alloys of Bi2Te3 and Bi4Te3 were all found to show atomic ordering after gentle annealing at very moderate temperatures of ˜100 ∘C . Upon annealing, BiTe transforms from bcc to the B2 (CsCl) crystal-structure type, and the other phases adopt semi-disordered variants thereof, featuring substitutional disorder on one of the two crystallographic sites. The transition pressures and atomic volumes of the alloy phases show systematic variations across the BimTen series including the end members Bi and Te. First-principles calculations were performed to characterize the electronic structure and chemical bonding properties of B2-type BiTe and to identify the driving forces of the ordering transition. The calculated Fermi surface of B2-type BiTe has an intricate structure and is predicted to undergo three topological changes between 20 and 60 GPa.

  18. Synthesis and characterization of bismuth telluride based nanostructured thermoelectric composite materials

    Science.gov (United States)

    Keshavarz Khorasgani, Mohsen

    Thermoelectric (TE) materials and devices are attractive in solid-state energy conversion applications such as waste heat recovery, air-conditioning, and refrigeration. Since the 1950's lots of unremitting efforts have been made to enhance the efficiency of energy conversion in TE materials (i. e. improving the figure of merit (ZT)), however, most of commercial bulk TE materials still suffer from low efficiency with ZTs around unity. To enhance the performance of bismuth telluride based TE alloys, we have developed composite TE materials, based on the idea that introducing more engineered interfaces in the bulk TE materials may lead to thermal conductivity reduction due to increased phonon scattering by these interfaces. In this approach it is expected that the electronic transport properties of the material are not effectively affected. Consequently, ZT enhancement can be achieved. In this dissertation we will discuss synthesis and characterization of two types of bismuth telluride based bulk composite TE materials. The first type is engineered to contain the presence of coherent interfaces between phases in the material resulting from different mixtures of totally miscible compounds with similar composition. The second type includes the nanocomposites with embedded foreign nano-particles in which the matrix and the particles are delimited by incoherent interfaces. The synthesis procedure, micro- and nano-structures as well as thermoelectric properties of these composites will be presented. In our study on the composites with coherent interfaces, we produced a series of different composites of p-type bismuth antimony telluride alloys and studied their microstructure and thermoelectric properties. Each composite consists of two phases that were obtained in powder form by mechanical alloying. Mixed powders in various proportions of the two different phases were consolidated by hot extrusion to obtain each bulk composite. The minimum grain size of bulk composites as

  19. Friction Consolidation Processing of n-Type Bismuth-Telluride Thermoelectric Material

    Energy Technology Data Exchange (ETDEWEB)

    Whalen, Scott A.; Jana, Saumyadeep; Catalini, David; Overman, Nicole R.; Sharp, Jeffrey

    2016-04-13

    This work focused on the development of a new mechanical processing route, called Friction Consolidation Processing (FCP), for densifying bismuth-telluride (Bi2Te3) powders into bulk form. FCP is a solid-state process wherein a rotating tool was used to generate severe plastic deformation within the Bi2Te3 powder, resulting in a recrystallizing flow of material. Upon cooling, the non-equilibrium microstructure within the flow was locked into the material. FCP was demonstrated on -325 mesh (~44 micron) n-type Bi2Te3 feedstock powder to form pucks with 92% theoretical density having a diameter of 25.4mm and thickness of 4.2mm. FCP was shown to achieve highly textured bulk materials, with sub-micron grain size, directly from coarse particle feedstock powders in a single process. An average grain size of 0.8 microns was determined for one sample and a multiple of uniform distribution (MUD) value of 15.49 was calculated for the (0001) pole figure from another sample. These results indicate that FCP can yield highly refined grains and textural alignment of the (0001) basal planes in Bi2Te3. ZT=0.37 at 336K was achieved for undoped stoichiometric Bi2Te3, which is near the “text book” value of ZT=0.5.

  20. Nanostructure Characterization of Bismuth Telluride-Based Powders and Extruded Alloys by Various Experimental Methods

    Science.gov (United States)

    Vasilevskiy, D.; Bourbia, O.; Gosselin, S.; Turenne, S.; Masut, R. A.

    2011-05-01

    High-resolution transmission electron microscopy (HRTEM) observations of mechanically alloyed powders and bulk extruded alloys give experimental evidence of nanosized grains in bismuth telluride-based materials. In this study we combine HRTEM observations and x-ray diffraction (XRD) measurements, of both mechanically alloyed powders and extruded samples, with mechanical spectroscopy (MS) of extruded rods. Both HRTEM and XRD show that nanostructures with an average grain size near 25 nm can be achieved within 2 h of mechanical alloying from pure elements in an attritor-type milling machine. Residual strain orthogonal to the c-axis of powder nanoparticles has been evaluated at about 1.2% by XRD peak broadening. In contrast, XRD has been found unreliable for evaluation of grain size in highly textured extruded materials for which diffraction conditions are similar to those of single crystals, while MS appears promising for study of bulk extruded samples. Nanostructured extruded alloys at room temperature exhibit an internal friction (IF) background that is one order of magnitude higher than that of conventional zone-melted material with a grain size of several millimeters. IF as a function of sample temperature gives activation energies that are also different between bulk materials having nano- and millimeter-size grains, a result that is attributed to different creep mechanisms. Nanograin size, as well as orientation and volumetric proportion, provide valuable information for optimization of technological parameters of thermoelectric alloys and should be carefully cross-examined by various independent methods.

  1. Lattice thermal conductivity diminution and high thermoelectric power factor retention in nanoporous macroassemblies of sulfur-doped bismuth telluride nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanliang; Mehta, Rutvik J.; Belley, Matthew; Han, Liang; Ramanath, Ganpati; Borca-Tasciuc, Theodorian

    2012-01-01

    We report ultralow lattice thermal conductivity in the 0.3 ≤ κL ≤ 0.6 W m⁻¹ K⁻¹ range in nanoporous bulk bismuth telluride pellets obtained by sintering chemically synthesized nanostructures, together with single-crystal-like electron mobilities and Seebeck coefficients at comparable charge carrier concentrations. The observed κL is up to 35% lower than classical effective medium predictions, and can be quantitatively explained by increased phonon scattering at nanopores and nanograins. Our findings are germane to tailoring nanoporous thermoelectric materials for efficient solid-state refrigeration, thermal energy harvesting, and thermal management applications.

  2. Spark plasma sintered bismuth telluride-based thermoelectric materials incorporating dispersed boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Williams, H.R., E-mail: hugo.williams@leicester.ac.uk [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ambrosi, R.M. [Space Research Centre, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Chen, K. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Friedman, U. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ning, H.; Reece, M.J. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Robbins, M.C.; Simpson, K. [European Thermodynamics Ltd., 8 Priory Business Park, Wistow Road, Kibworth LE8 0R (United Kingdom); Stephenson, K. [European Space Agency, ESTEC TEC-EP, Keplerlaan 1, 2201AZ Noordwijk (Netherlands)

    2015-03-25

    Highlights: • Nano-B{sub 4}C reinforced Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} p-type thermoelectric produced by SPS. • Addition of B{sub 4}C up to 0.2 vol% to SPS’d material has little effect on zT. • Vickers hardness improved by 27% by adding 0.2 vol% B{sub 4}C. • Fracture toughness of SPS material: K{sub IC} = 0.80 MPa m{sup 1/2} by SEVNB. • Mechanical properties much better than commercial directionally solidified material. - Abstract: The mechanical properties of bismuth telluride based thermoelectric materials have received much less attention in the literature than their thermoelectric properties. Polycrystalline p-type Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} materials were produced from powder using spark plasma sintering (SPS). The effects of nano-B{sub 4}C addition on the thermoelectric performance, Vickers hardness and fracture toughness were measured. Addition of 0.2 vol% B{sub 4}C was found to have little effect on zT but increased hardness by approximately 27% when compared to polycrystalline material without B{sub 4}C. The K{sub IC} fracture toughness of these compositions was measured as 0.80 MPa m{sup 1/2} by Single-Edge V-Notched Beam (SEVNB). The machinability of polycrystalline materials produced by SPS was significantly better than commercially available directionally solidified materials because the latter is limited by cleavage along the crystallographic plane parallel to the direction of solidification.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Role of stirring assist during solvothermal synthesis for preparing single-crystal bismuth telluride hexagonal nanoplates

    Energy Technology Data Exchange (ETDEWEB)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Kai, Shintaro; Wada, Kodai [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Takasugi, Soichi [Graduate School of Science and Technology, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Tomita, Koji [Department of Chemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

    2016-04-15

    We investigated the role of stirring assist during solvothermal synthesis for preparing high quality bismuth telluride (Bi{sub 2}Te{sub 3}) hexagonal nanoplates. We performed a series of experiments that comprised solvothermal synthesis with stirring assist at 500 rpm and without stirring assist. As a result, high purity Bi{sub 2}Te{sub 3} hexagonal nanoplates with uniform morphology and edge length of 400–800 nm were obtained by solvothermal synthesis using stirring assist, whereas intermediate products such as tellurium and tellurium oxide compounds were also produced besides the Bi{sub 2}Te{sub 3} hexagonal nanoplates by solvothermal synthesis without stirring assist. To further study the nanostructure of the nanoplates with stirring assist, we performed high-resolution transmission electron microscopy and selected-area electron diffraction analysis. It was found that the Bi{sub 2}Te{sub 3} hexagonal nanoplates were composed of rhombohedral phases and highly single-crystalline structures. Based on the experimental and analytical results, we propose a possible reaction process and growth mechanism of the Bi{sub 2}Te{sub 3} hexagonal nanoplates. The reaction rate is the key factor to control the shapes of nanostructures. When the reaction rate was sufficient, it proceeded to the final stage, and then Bi{sub 2}Te{sub 3} nanoplates were produced. However, when the reaction rate was insufficient, the entire morphology evolution process was terminated at the intermediate stage, and intermediate products besides Bi{sub 2}Te{sub 3} nanoplates were also produced. - Highlights: • High quality Bi{sub 2}Te{sub 3} hexagonal nanoplates were prepared by solvothermal synthesis. • Role of stirring assist during the solvothermal synthesis were investigated. • Bi{sub 2}Te{sub 3} hexagonal nanoplates with edge length of 400–800 nm were obtained. • Bi{sub 2}Te{sub 3} hexagonal nanoplates were composed of single-crystalline structures. • The reaction rate is the key

  6. A simple fast microwave-assisted synthesis of thermoelectric bismuth telluride nanoparticles from homogeneous reaction-mixture

    Science.gov (United States)

    Pradhan, Susmita; Das, Rashmita; Bhar, Radhaballabh; Bandyopadhyay, Rajib; Pramanik, Panchanan

    2017-02-01

    A new simple chemical method for synthesis of nanocrystalline bismuth telluride (Bi2Te3) has been developed by microwave assisted reduction of homogeneous tartrate complexes of bismuth and tellurium metal ions with hydrazine. The reaction is performed at pH 10. The nano-crystallites have rhombohedral phase identified by XRD. The size distribution of nanoparticle is narrow and it ranges between 50 to 70 nm. FESEM shows that the fine powders are composed of small crystallites. The TEM micrographs show mostly deformed spherical particles and the lattice fringes are found to be 0.137 nm. Energy dispersive X-ray spectroscopy (EDX) analysis shows the atomic composition ratio between bismuth and tellurium is 2:3. Thermoelectric properties of the materials are studied after sintering by spark plasma sintering method (SPS). The grain size of the material after sintering is in the nanometer range. The material shows enhanced Seebeck coefficient and electrical conductivity value at 300 K. The figure of merit is found to be 1.18 at 300 K.

  7. Bismuth telluride topological insulator nanosheet saturable absorbers for q-switched mode-locked Tm:ZBLAN waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiantao; Gross, Simon; Withford, Michael J.; Fuerbach, Alexander [Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and MQ Photonics Research Centre, Dept. of Physics and Astronomy, Macquarie Univ., NSW (Australia); Zhang, Han; Guo, Zhinan [SZU-NUS Collaborative Innovation Centre for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education, College of Optoelectronic Engineering, Shenzhen Univ. (China)

    2016-08-15

    Nanosheets of bismuth telluride (Bi{sub 2}Te{sub 3}), a topological insulator material that exhibits broadband saturable absorption due to its non-trivial Dirac-cone like energy structure, are utilized to generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers of a carefully prepared Bi{sub 2}Te{sub 3} solution onto a glass substrate, the modulation depth and the saturation intensity of the fabricated devices can be controlled and optimized. This approach enables the realization of saturable absorbers that feature a modulation depth of 13% and a saturation intensity of 997 kW/cm{sup 2}. For the first time to our knowledge, Q-switched mode-locked operation of a linearly polarized mid-IR ZBLAN waveguide chip laser was realized in an extended cavity configuration using the topological insulator Bi{sub 2}Te{sub 3}. The maximum average output power of the laser is 16.3 mW and the Q-switched and mode-locked repetition rates are 44 kHz and 436 MHz, respectively. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Synthesis, characterization and enhanced thermoelectric performance of structurally ordered cable-like novel polyaniline-bismuth telluride nanocomposite

    Science.gov (United States)

    Chatterjee, Krishanu; Mitra, Mousumi; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali

    2013-05-01

    Bismuth telluride (Bi2Te3) nanorods and polyaniline (PANI) nanoparticles have been synthesized by employing solvothermal and chemical oxidative processes, respectively. Nanocomposites, comprising structurally ordered PANI preferentially grown along the surface of a Bi2Te3 nanorods template, are synthesized using in situ polymerization. X-ray powder diffraction, UV-vis and Raman spectral analysis confirm the highly ordered chain structure of PANI on Bi2Te3 nanorods, leading to a higher extent of doping, higher chain mobility and enhancement of the thermoelectric performance. Above 380 K, the PANI-Bi2Te3 nanocomposite with a core-shell/cable-like structure exhibits a higher thermoelectric power factor than either pure PANI or Bi2Te3. At room temperature the thermal conductivity of the composite is lower than that of its pure constituents, due to selective phonon scattering by the nanointerfaces designed in the PANI-Bi2Te3 nanocable structures. The figure of merit of the nanocomposite at room temperature is comparable to the values reported in the literature for bulk polymer-based composite thermoelectric materials.

  9. Acetic acid-confined synthesis of uniform three-dimensional (3D) bismuth telluride nanocrystals consisting of few-quintuple-layer nanoplatelets

    KAUST Repository

    Yuan, Qiang

    2011-01-01

    High-selectivity, uniform three-dimensional (3D) flower-like bismuth telluride (Bi2Te3) nanocrystals consisting of few-quintuple-layer nanoplatelets with a thickness down to 4.5 nm were synthesized for the first time by a facile, one-pot polyol method with acetic acid as the structure-director. Micrometre-sized 2D films and honeycomb-like spheres can be obtained using the uniform 3D Bi2Te3 nanocrystals as building blocks. © The Royal Society of Chemistry 2011.

  10. Facile synthesis and thermoelectric studies of n-type bismuth telluride nanorods with cathodic stripping Te electrode

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Guoqiu [School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, Jiangsu (China); Li, Yusong [School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, Jiangsu (China); Department of Chemistry and Chemical Engineering, Southeast University, 210092 Jiangsu (China); Bao, Ning [School of Public Health, Nantong University, Nantong 226019, Jiangsu (China); Miao, Jianwen [School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, Jiangsu (China); Ge, Cunwang, E-mail: gecunwang@ntu.edu.cn [School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, Jiangsu (China); Wang, Yihong [Department of Chemistry and Chemical Engineering, Southeast University, 210092 Jiangsu (China)

    2014-01-15

    Bismuth telluride (Bi{sub 2}Te{sub 3}) nanorods (NRs) of n-type thermoelectric materials were prepared using an electrogenerated precursor of tellurium electrode in the presence of Bi{sup 3+} and mercapto protecting agent in aqueous solution under atmosphere condition. The optimal preparation conditions were obtained with ratio of Bi{sup 3+} to mercapto group and Te coulomb by photoluminescence spectra. The mechanism for generation of Bi{sub 2}Te{sub 3} precursor was investigated via the cyclic voltammetry. The highly crystalline rhombohedral structure of as-prepared Bi{sub 2}Te{sub 3} NRs with the shell of Bi{sub 2}S{sub 3} was evaluated with high resolution transmission electron microscopy (HRTEM) and powder X-ray diffraction (XRD) spectroscopy. The near-infrared absorption of synthetic Bi{sub 2}Te{sub 3} NRs was characterized with spectrophotometer to obtain information of electron at interband transition. The thermoelectric performance of Bi{sub 2}Te{sub 3} NRs was assessed with the result of electrical resistivity, Seebeck coefficient, thermal conductivity, and the figure of merit ZT parameters, indicating that thermoelectric performance of as-prepared Bi{sub 2}Te{sub 3} nanocrystals was improved by reducing thermal conductivity while maintaining the power factor. - Graphical abstract: The nanorods of n-type chalcogenides semiconductors of Bi{sub 2}Te{sub 3} are prepared using electrochemical technique with Te electrode. The highly crystalline rhombohedral structure of Bi{sub 2}Te{sub 3} nanorods with the shell of Bi{sub 2}S{sub 3} is demonstrated. The thermoelectric measurement indicated that thermoelectric performance of Bi{sub 2}Te{sub 3} NRs was improved by a highly reduced thermal conductivity while maintaining the power factor. - Highlights: • The n-type Bi{sub 2}Te{sub 3} nanorods are prepared using an electrogenerated precursor. • The rhombohedral structure of Bi{sub 2}Te{sub 3} nanorods with the shell of Bi{sub 2}S{sub 3} is demonstrated. • Bi

  11. Linearly polarized, Q-switched, erbium-doped fiber laser incorporating a bulk-structured bismuth telluride/polyvinyl alcohol saturable absorber

    Science.gov (United States)

    Lee, Jinho; Lee, Junsu; Koo, Joonhoi; Chung, Hojai; Lee, Ju Han

    2016-07-01

    We experimentally demonstrate a linearly polarized, passively Q-switched, erbium (Er)-doped fiber laser using a saturable absorber (SA) based on a composite consisting of a bulk-structured bismuth telluride (Bi2Te3) topological insulator (TI) and polyvinyl alcohol (PVA). The SA was constructed on a polarization maintaining (PM) fiber ferrule platform, which had a sandwich structure. Its saturation intensity and modulation depth were measured to be ˜ and ˜4.1%, respectively. Using the prepared Bi2Te3/PVA SA in a PM Er-doped fiber ring laser, stable Q-switched pulses with a degree of polarization of ˜98.6% and an azimuth angle of ˜-0.34 deg were demonstrated. The minimum pulse width was measured to be ˜1.58 μs at a repetition rate of 47.1 kHz. This experimental demonstration verifies that a thin film based on a bulk-structured Bi2Te3 TI can fit into a sandwich-structured SA based on PM fiber ferrules.

  12. Bismuth telluride (Bi2Te3) nanowires: synthesis by cyclic electrodeposition/stripping, thinning by electrooxidation, and electrical power generation.

    Science.gov (United States)

    Menke, E J; Brown, M A; Li, Q; Hemminger, J C; Penner, R M

    2006-12-01

    Nanowires composed of the thermoelectric material Bi2Te3 were synthesized on highly oriented pyrolytic graphite (HOPG) electrodes using the electrochemical step edge decoration (ESED) method. Nanowire synthesis was initiated by applying a voltage pulse of -0.75 V versus SCE for 5 ms to an HOPG electrode in an aqueous solution containing both Bi3+ and TeO22-, thereby producing nuclei at the step edges. Bi2Te3 was electrodeposited onto these nuclei using a cyclic electrodeposition-stripping scheme that involved the electrodeposition of bismuth-rich Bi2Te3 on a negative-going voltammetric scan (to -0.05 V) and the subsequent anodic stripping of excess bismuth from these nanowires during a positive-going scan (to +0.35 V). When this cycle was repeated 10-50 times, Bi2Te3 nanowires in the 100-300-nm-diameter range were obtained. These nanowires were narrowly dispersed in diameter (RSDdia = 10-20%), were more than 100 microm in length, and were organized into parallel arrays containing hundreds of wires. Smaller nanowires, with diameters down to 30 nm, were obtained by electrooxidizing 150-nm-diameter Bi2Te3 nanowires at +0.37 V under conditions of kinetic control. This oxidation process unexpectedly improved the uniformity of Bi2Te3 nanowires, and X-ray photoelectron spectroscopy (XPS) shows that these nanowires retain a Bi2Te3 core but also have a thin surface layer composed of Bi and Te oxides. The ability of Bi2Te3 nanowires to generate electrical power was assessed by transferring ensembles of these nanowires onto cyanoacrylate-coated glass surfaces and evaporating 4-point nickel contacts. A dimensionless figure of merit, ZT, ranging from 0 to 0.85 was measured for fresh samples that were less than 1 day old. XPS reveals that Bi2Te3 nanowires are oxidized within a week to Bi2O3 and TeO2. These oxides may interfere with the application by evaporation of electrical contacts to these nanowires.

  13. Mechanical properties of bismuth telluride (Bi{sub 2}Te{sub 3}) processed by high pressure torsion (HPT); Propiedades mecanicas del telururo de bismuto (Bi{sub 2}Te{sub 3}) procesado mediante torsion bajo alta presion (HPT)

    Energy Technology Data Exchange (ETDEWEB)

    Santamaria, J. A.; Alkorta, J.; Gil Sevillano, J.

    2013-06-01

    Bismuth telluride, Bi{sub 2}Te{sub 3}, is the main thermoelectric material currently in use for commercial cooling devices or for energy harvesting near room temperature. Because of its highly anisotropic layered structure, Bi{sub 2}Te{sub 3} is very brittle, failing by cleavage along its basal plane. Refining its grain size is expected to increase its toughness with the advantage that, simultaneously, its thermoelectric figure of merit results increased. In this work, powders of the compound have been compacted by conventional methods as well as by severe plastic deformation under high pressure (3 GPa) using high pressure torsion (HPT, one turn at room temperature). Near-theoretical density has been achieved. The hardness and toughness of the compacts have been assessed by micro and nano-indentation. (Author) 11 refs.

  14. Ultrafast Study of Carrier Interaction in Bismuth Telluride Thin Film%碲化铋薄膜载能粒子相互作用的超快研究

    Institute of Scientific and Technical Information of China (English)

    马维刚; 张兴

    2012-01-01

    Bismuth telluride, with narrow band gap, large electrical conductivity, large Seebeck coefficient, and low thermal conductivity, is one of the best thermoelectric materials with the highest figure of merit at room temperature. In addition, thin film and superlattice are considered to be the feasible ways to improve the performance of thermoelectric materials. And hence, it is important to study the carrier interaction in bismuth telluride thin film. In this paper, the carrier interaction of 100 nm thick bismuth telluride film deposited on silicon substrate has been studied by applying the femtosecond laser pump-probe transient thermoreflectance technique. Different carrier interaction processes, including electrons excited from valence band to conduction band, electron-hole recombination, and energy coupling from photoexcited carriers to lattice have been studied respectively by changing the delay time step of the probe pulse. Also, an acoustic wave generated from the thermal stress has been observed and the corresponding extracted longitudinal wave velocity is 2649 m s-1.%碲化铋禁带宽度非常窄而具有高电导率和塞贝克系数,同时具有低热导率,成为已知室温下优值系数最高的热电材料。已有研究表明,纳米薄膜和超晶格是进一步提高材料热电性能的可行途径。因此超快研究碲化铋纳米薄膜中载能子间的相互作用过程对开发高性能热电材料有重要意义。本文采用飞秒激光泵浦一探测技术,实验研究了沉积在硅基底上厚度为100nm碲化铋薄膜中各载能粒子的相互作用过程。通过改变延迟时间步长,分别观察到价带电子被光子激发跃迁至导带,激发电子在导带内与声子的能量弛豫及导带电子与空穴复合跃迁至价带,并将能量传递给声子导致声子温度升高的过程。此外,还观察到热应力产生的声波,并据此得到了碲化铋薄膜中纵波声速为2649ms-1。

  15. Growth and characterization of bismuth telluride nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Picht, Oliver

    2010-05-26

    Polycrystalline Bi{sub 2}Te{sub 3} nanowires are electrochemically grown in ion track-etched polycarbonate membranes. Potentiostatic growth is demonstrated in templates of various thicknesses ranging from 10 to 100 {mu}m. The smallest observed nanowire diameters are 20 nm in thin membranes and approx. 140-180 nm in thicker membranes. The influence of the various deposition parameters on the nanowire growth rate is presented. Slower growth rates are attained by selective change of deposition potentials and lower temperatures. Nanowires synthesized at slower growth rates have shown to possess a higher degree of crystalline order and smoother surface contours. With respect to structural properties, X-ray diffraction and transmission electron microscopy verified the growth of Bi{sub 2}Te{sub 3} and evidenced the stability of specific properties, e.g. grain size or preferential orientation, with regard to variations in the deposition conditions. The interdependency of the fabrication parameters, i.e. temperature, deposition potential and nanochannel diameters, is demonstrated for wires grown in 30 {mu}m thick membranes. It is visible from diffraction analysis that texture is tunable by the growth conditions but depends also on the size of the nanochannels in the template. Both (015) and (110) reflexes are observed for the nanowire arrays. Energy dispersive X-ray analysis further points out that variation of nanochannel size could lead to a change in elemental composition of the nanowires. (orig.)

  16. Lead telluride alloy thermoelectrics

    Directory of Open Access Journals (Sweden)

    Aaron D. LaLonde

    2011-11-01

    Full Text Available The opportunity to use solid-state thermoelectrics for waste heat recovery has reinvigorated the field of thermoelectrics in tackling the challenges of energy sustainability. While thermoelectric generators have decades of proven reliability in space, from the 1960s to the present, terrestrial uses have so far been limited to niche applications on Earth because of a relatively low material efficiency. Lead telluride alloys were some of the first materials investigated and commercialized for generators but their full potential for thermoelectrics has only recently been revealed to be far greater than commonly believed. By reviewing some of the past and present successes of PbTe as a thermoelectric material we identify the issues for achieving maximum performance and successful band structure engineering strategies for further improvements that can be applied to other thermoelectric materials systems.

  17. Novel Bismuth Nanotubes

    Institute of Scientific and Technical Information of China (English)

    苏长荣; 李家明

    2002-01-01

    Theoretical investigations show that bismuth nanotubes are semiconductors for all diameters. For smalldiameter bismuth nanotubes, the band structures and bandgaps vary strongly with the strong hybridization effect. When the diameters are larger than 18 A, the bandgaps ofBi (n, n) and (n, 0) nanotubes approach 0.63 e V, corresponding to the bandgap of bismuth sheet at the Γ point. Thus, bismuth nanotubes are expected to be a potential semiconductor nanomaterial in future nanoelectronics.

  18. Spin dynamics of complex oxides, bismuth-antimony alloys, and bismuth chalcogenides

    Science.gov (United States)

    Sahin, Cuneyt

    V, suggesting the potential for doping or voltage tuned spin Hall current. We have also calculated intrinsic spin Hall conductivities of bismuth selenide and bismuth telluride topological insulators from an effective tight-binding Hamiltonian including two nearest-neighbor interactions. We showed that both materials exhibit giant spin Hall conductivities calculated from the Kubo formula in linear response theory and the clean static limit. We conclude that bismuth-antimony alloys and bismuth chalcogenides are primary candidates for efficiently generating spin currents through the spin Hall effect.

  19. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L. (University of South Florida, Tampa, FL (United States))

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

  20. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75 percent or higher at 0.44 microns and a photovoltaic efficiency of 11.5 percent or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65 percent and a photovoltaic conversion efficiency of 5 percent and 8 percent, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD(1-x)Zn(1-x)Te, and Hg(1-x)Zn(x)Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400 C using TEGa and AsH3 as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd(1-x)Zn(x)Te, and Hg(1-x)Zn(x)Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized.

  1. Nanocalorimetry of bismuth nanoparticles

    Science.gov (United States)

    Olson, Eric Ashley

    The properties of nanosized bismuth particles are investigated using a nanocalorimetric technique. A brief description of the experimental method and data analysis procedures is reported. Bismuth nanoparticles are found to melt at a temperature below that of bulk material, but higher than expected using the standard model. Also included is the results of a finite element analysis and simulated melting of bismuth films on various kinds of sensors. Temperature distributions are found to be nonuniform for calorimetric sensors with Al metallizations, but much more uniform for Pt metallized sensors. The consequences of this nonuniformity on caloric data are discussed.

  2. Ellipsometric Studies on Silver Telluride Thin Films

    Directory of Open Access Journals (Sweden)

    M. Pandiaraman

    2011-01-01

    Full Text Available Silver telluride thin films of thickness between 45 nm and 145 nm were thermally evaporated on well cleaned glass substrates at high vacuum better than 10 – 5 mbar. Silver telluride thin films are polycrystalline with monoclinic structure was confirmed by X-ray diffractogram studies. AFM and SEM images of these films are also recorded. The phase ratio and amplitude ratio of these films were recorded in the wavelength range between 300 nm and 700 nm using spectroscopic ellipsometry and analysed to determine its optical band gap, refractive index, extinction coefficient, and dielectric functions. High absorption coefficient determined from the analysis of recorded spectra indicates the presence of direct band transition. The optical band gap of silver telluride thin films is thickness dependent and proportional to square of reciprocal of thickness. The dependence of optical band gap of silver telluride thin films on film thickness has been explained through quantum size effect.

  3. Dendritic tellurides acting as antioxidants

    Institute of Scientific and Technical Information of China (English)

    XU Huaping; WANG Yapei; WANG Zhiqiang; LIU Junqiu; Mario Smet; Wim Dehaen

    2006-01-01

    We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the periphery which act as glutathione peroxidase (GPx) mimics. These series of compounds were well characterized by 1H-NMR, 13C-NMR and ESI-MS. Using different ROOH (H2O2, cumene hydroperoxide) for testing the antioxidizing properties of these compounds, we have found that from generation 0 to 2, the activity of the dendritic GPx mimics first decreased and then increased. This can be explained on the basis of a greater steric hindrance, going from generation 0 to 1, and stronger binding interactions going from generation 1 to 2. In other words, there exists a balance between binding interactions and steric hindrance that may optimize the GPx activity.

  4. Bismuth vanadate process

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.M.

    1990-06-26

    This patent describes the process for the preparation of bismuth vanadate and bismuth vanadate-containing compounds wherein the precursor materials are calcined in the solid state at temperatures sufficient to react the precursor materials to prepare the vanadate compounds. It comprises: wet grinding the calcined product, contacting the calcined product with sufficient alkaline material to provide a pH level of 7.0-13.0 and recovering the treated product, the wet grinding of the calcined product being conducted either in the presence of the alkaline material or prior to the contacting with the alkaline material.

  5. Cadmium telluride quantum dots advances and applications

    CERN Document Server

    Donegan, John

    2013-01-01

    Optical Properties of Bulk and Nanocrystalline Cadmium Telluride, Núñez Fernández and M.I. VasilevskiyAqueous Synthesis of Colloidal CdTe Nanocrystals, V. Lesnyak, N. Gaponik, and A. EychmüllerAssemblies of Thiol-Capped CdTe Nanocrystals, N. GaponikFörster Resonant Energy Transfer in CdTe Nanocrystal Quantum Dot Structures, M. Lunz and A.L. BradleyEmission of CdTe Nanocrystals Coupled to Microcavities, Y.P. Rakovich and J.F. DoneganBiological Applications of Cadmium Telluride Semiconductor Quantum Dots, A. Le Cign

  6. THORIUM DISPERSION IN BISMUTH

    Science.gov (United States)

    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.

  7. Layered bismuth vanadate ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Osipyan, V.G.; Savchenko, L.M.; Elbakyan, V.L.; Avakyan, P.B.

    1987-08-01

    The authors synthesize new layered bismuth vanadate ferroelectrics. The x-ray diffraction characteristics of Bi/sub 2/VO/sub 5.5/ are shown. Thermal expansion of ceramics with various compositions are presented, as are the temperature dependences of the dielectric constant of the ceramic with various compositions. Unit-cell parameters, Curie temperature, electrical conductivity and the dielectric characteristics of the compositions studied are shown.

  8. Bismuth toxicity in patients treated with bismuth iodoform paraffin packs.

    Science.gov (United States)

    Atwal, A; Cousin, G C S

    2016-01-01

    Bismuth is a heavy metal used in bismuth iodoform paraffin paste (BIPP) antiseptic dressings and in a number of other medical preparations. It can be absorbed systemically and cause toxicity. We report 2 cases of such neurotoxicity after it was used in operations on the jaws.

  9. Tribochemistry of Bismuth and Bismuth Salts for Solid Lubrication

    NARCIS (Netherlands)

    Gonzalez Rodriguez, P.; Nieuwenhuijzen, van den K.J.H.; Lette, W.; Schipper, D.J.; Elshof, ten J.E.

    2016-01-01

    One of the main trends in the past decades is the reduction of wastage and the replacement of toxic compounds in industrial processes. Some soft metallic particles can be used as nontoxic solid lubricants in high-temperature processes. The behavior of bismuth metal particles, bismuth sulfide (Bi2S3)

  10. Ellipsometric Analysis of Cadmium Telluride Films’ Structure

    Directory of Open Access Journals (Sweden)

    Anna Evmenova

    2015-01-01

    Full Text Available Ellipsometric analysis of CdTe films grown on Si and CdHgTe substrates at the “hot-wall” epitaxy vacuum setup has been performed. It has been found that ellipsometric data calculation carried out by using a simple one-layer film model leads to radical distortion of optical constants spectra: this fact authenticates the necessity to attract a more complicated model that should include heterogeneity of films. Ellipsometric data calculation within a two-layer film model permitted to conclude that cadmium telluride films have an outer layer that consists of the three-component mixture of CdTe, cavities, and basic matter oxide. Ratio of mixture components depends on the time of deposition, that is, on the film thickness. The inner layer consists of cadmium telluride.

  11. Molecular modelling of some para-substituted aryl methyl telluride and diaryl telluride antioxidants

    Science.gov (United States)

    Frisell, H.; Engman, L.

    2000-08-01

    Quantum mechanical calculations using the 3-21G(d) basis-set were performed on some p-substituted diaryl tellurides and aryl methyl tellurides, and the corresponding cationic radicals of these compounds. Calculated relative radical stabilization energies (RSE:s) were shown to correlate with experimentally determined peak oxidation potentials ( R=0.93) and 125Te-NMR chemical shifts ( R=0.91). A good correlation was also observed between the RSE:s and the Mulliken charge at the tellurium atoms ( R=0.97). The results showed that Hartree-Fock calculations using the 3-21G(d) basis set was sufficiently accurate for estimating the impact of p-substituents in aryl tellurides on experimentally determined properties such as peak oxidation potentials and 125Te-NMR chemical shifts.

  12. Bismuth(V) oxide and silver bismuthate as oxidizing agents for gas-chromatographic elemental microanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Shvykin, A.Y.; Platonov, V.V.; Proskuryakov, V.P.; Chilachava, K.B.; Khmarin, E.M.; Kovtun, I.V. [Tolstoy State Pedag University, Tula (Russian Federation)

    2004-07-01

    Bismuth(V) oxide, silver bismuthate, and a mixture of bismuth(V) oxide with fine silver powder were studied as oxidizing additives in gas-chromatographic elemental microanalysis of readily combustible organic substances and coal.

  13. Bismuth ochers from San Diego Co., California

    Science.gov (United States)

    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.

  14. Energetics of bismuth vanadate

    Energy Technology Data Exchange (ETDEWEB)

    Nagabhushana, G.P.; Tavakoli, A.H.; Navrotsky, A., E-mail: anavrotsky@ucdavis.edu

    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.

  15. Energetics of bismuth vanadate

    Science.gov (United States)

    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.

  16. Boundary Engineering for the Thermoelectric Performance of Bulk Alloys Based on Bismuth Telluride.

    Science.gov (United States)

    Mun, Hyeona; Choi, Soon-Mok; Lee, Kyu Hyoung; Kim, Sung Wng

    2015-07-20

    Thermoelectrics, which transports heat for refrigeration or converts heat into electricity directly, is a key technology for renewable energy harvesting and solid-state refrigeration. Despite its importance, the widespread use of thermoelectric devices is constrained because of the low efficiency of thermoelectric bulk alloys. However, boundary engineering has been demonstrated as one of the most effective ways to enhance the thermoelectric performance of conventional thermoelectric materials such as Bi2 Te3 , PbTe, and SiGe alloys because their thermal and electronic transport properties can be manipulated separately by this approach. We review our recent progress on the enhancement of the thermoelectric figure of merit through boundary engineering together with the processing technologies for boundary engineering developed most recently using Bi2 Te3 -based bulk alloys. A brief discussion of the principles and current status of boundary-engineered bulk alloys for the enhancement of the thermoelectric figure of merit is presented. We focus mainly on (1) the reduction of the thermal conductivity by grain boundary engineering and (2) the reduction of thermal conductivity without deterioration of the electrical conductivity by phase boundary engineering. We also discuss the next potential approach using two boundary engineering strategies for a breakthrough in the area of bulk thermoelectric alloys.

  17. Interface Characterization of Cobalt Contacts on Bismuth Selenium Telluride for Thermoelectric Devices

    KAUST Repository

    Gupta, R. P.

    2009-08-13

    Sputtered Co is investigated as a suitable contact metal for bulk Bi2 (Te,Se) 3, and the results are compared to sputtered Ni. The coefficient of thermal expansion of Co matches that of bulk Bi 2 (Te,Se) 3 used in our study, and the compatible interface favors the selection of Co as a contact metal. Significant Ni diffusion into Bi2 (Te,Se) 3 was observed. In contrast, Co on Bi2 (Te,Se) 3 shows significantly less diffusion, even at anneal temperatures as high as 200°C. CoTe2 is the preferred phase that is formed. First principles calculations for Bi2 Te 3 support the experimental observation. © 2009 The Electrochemical Society.

  18. Thermoelectric transport in surface- and antimony-doped bismuth telluride nanoplates

    Science.gov (United States)

    Pettes, Michael Thompson; Kim, Jaehyun; Wu, Wei; Bustillo, Karen C.; Shi, Li

    2016-10-01

    We report the in-plane thermoelectric properties of suspended (Bi1-xSbx)2Te3 nanoplates with x ranging from 0.07 to 0.95 and thicknesses ranging from 9 to 42 nm. The results presented here reveal a trend of increasing p-type behavior with increasing antimony concentration, and a maximum Seebeck coefficient and thermoelectric figure of merit at x ˜ 0.5. We additionally tuned extrinsic doping of the surface using a tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) coating. The lattice thermal conductivity is found to be below that for undoped ultrathin Bi2Te3 nanoplates of comparable thickness and in the range of 0.2-0.7 W m-1 K-1 at room temperature.

  19. Fabrication of Thermoelectric Sensor and Cooling Devices Based on Elaborated Bismuth-Telluride Alloy Thin Films

    Directory of Open Access Journals (Sweden)

    Abdellah Boulouz

    2014-01-01

    Full Text Available The principal motivation of this work is the development and realization of smart cooling and sensors devices based on the elaborated and characterized semiconducting thermoelectric thin film materials. For the first time, the details design of our sensor and the principal results are published. Fabrication and characterization of Bi/Sb/Te (BST semiconducting thin films have been successfully investigated. The best values of Seebeck coefficient (α(T at room temperature for Bi2Te3, and (Bi1−xSbx2Te3 with x = 0.77 are found to be −220 µV/K and +240 µV/K, respectively. Fabrication and evaluation of performance devices are reported. 2.60°C of cooling of only one Peltier module device for an optimal current of Iopt=2.50 mA is obtained. The values of temperature measured by infrared camera, by simulation, and those measured by the integrated and external thermocouple are reported. A sensitivity of the sensors of 5 mV Torr−1 mW−1 for the pressure sensor has been found with a response time of about 600 ms.

  20. Growth of bismuth telluride thin film on Pt by electrochemical atomic layer epitaxy

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Jun-you; GAO Xian-hui; HOU Jie; ZHANG Tong-jun; CUI Kun

    2005-01-01

    An automated thin-layer flow cell electrodeposition system was developed for growing Bi2 Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt,this reductive Te underpotential deposition (UPD)/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4: 3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO2+ reduction excludes the possibility of Bi2 Te3 formation. X-ray photoelectron spectroscopy (XPS) analysis also reveals that the incomplete charge transfer in HTeO2+ occurs in Te direct deposition. The effective way of depositing Bi2 Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). A polycrystalline characteristic was confirmed by XRD. The 2 : 3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about 0.3 - 0.4 μm in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.

  1. Thermoelectric Transport in Surface- and Antimony-Doped Bismuth Telluride Nanoplates

    Science.gov (United States)

    2016-07-25

    to the very thin samples, and (2) even for large sample volumes, EDS is seen as a qualitative tool where uncertainty can be on the order of several...nanoplates in an uncorrected FEI Titan 80-300 TEM operating at 120 kV using a FEI Super-X Quad windowless detector based on silicon drift technology with

  2. Effect of preparation procedure and nanostructuring on the thermoelectric properties of the lead telluride-based material system AgPbmBiTe2+m (BLST-m)

    Science.gov (United States)

    Falkenbach, Oliver; Schmitz, Andreas; Hartung, David; Dankwort, Torben; Koch, Guenter; Kienle, Lorenz; Klar, Peter J.; Mueller, Eckhard; Schlecht, Sabine

    2016-06-01

    We report on the preparation and thermoelectric properties of the quaternary system AgPbmBiTe2+m (Bismuth-Lead-Silver-Tellurium, BLST-m) that were nanostructured by mechanical alloying. Nanopowders of various compositions were compacted by three different methods: cold pressing/annealing, hot pressing, and short term sintering. The products are compared with respect to microstructure and sample density. The thermoelectric properties were measured: thermal conductivity in the temperature range from 300 K to 800 K and electrical conductivity and Seebeck coefficient between 100 K and 800 K. The compacting method and the composition had a substantial impact on carrier concentration and mobility as well as on the thermoelectric parameters. Room temperature Hall measurements yielded carrier concentrations in the order of 1019 cm-3, slightly increasing with increasing content of the additive silver bismuth telluride to the lead telluride base. ZT values close to the ones of bulk samples were achieved. X-ray diffraction and transmission electron microscopy (TEM) showed macroscopically homogeneous distributions of the constituting elements inside the nanopowders ensembles, indicating a solid solution. However, high resolution transmission electron microscopy (HRTEM) revealed disorder on the nanoscale inside individual nanopowders grains.

  3. Mineral resource of the month: bismuth

    Science.gov (United States)

    Carlin, 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.

  4. The single molecular precursor approach to metal telluride thin films: imino-bis(diisopropylphosphine tellurides) as examples.

    Science.gov (United States)

    Ritch, Jamie S; Chivers, Tristram; Afzaal, Mohammad; O'Brien, Paul

    2007-10-01

    Interest in metal telluride thin films as components in electronic devices has grown recently. This tutorial review describes the use of single-source precursors for the preparation of metal telluride materials by aerosol-assisted chemical vapour deposition (AACVD) and acquaints the reader with the basic techniques of materials characterization. The challenges in the design and synthesis of suitable precursors are discussed, focusing on metal complexes of the recently-developed imino-bis(diisopropylphosphine telluride) ligand. The generation of thin films and nanoplates of CdTe, Sb(2)Te(3) and In(2)Te(3) from these precursors are used as illustrative examples.

  5. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-06-01

    This National Center for Photovoltaics sheet describes the capabilities of its polycrystalline thin-film research in the area of cadmium telluride. The scope and core competencies and capabilities are discussed.

  6. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for Polycrystalline Thin-Film Research: Cadmium Telluride at the National Center for Photovoltaics.

  7. Studies of antimony telluride and copper telluride films electrodeposition from choline chloride containing ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Catrangiu, Adriana-Simona; Sin, Ion [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Prioteasa, Paula [INCDIE ICPE-Advanced Research, Splaiul Unirii 313, Bucharest (Romania); Cotarta, Adina [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Cojocaru, Anca, E-mail: a_cojocaru@chim.upb.ro [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Anicai, Liana [Center of Surface Science and Nanotechnology, University POLITEHNICA of Bucharest, Splaiul Independentei 313, Bucharest (Romania); Visan, Teodor [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania)

    2016-07-29

    Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the deposition of antimony telluride or copper telluride from ionic liquid consisting in mixture of choline chloride with oxalic acid. In addition, the cathodic process during copper telluride formation was studied in the mixture of choline chloride with ethylene glycol. The results indicate that the Pt electrode is first covered with a Te layer, and then the more negative polarisation leads to the deposition of Sb{sub x}Te{sub y} or Cu{sub x}Te{sub y} semiconductor compounds. Thin films were deposited on copper and carbon steel at 60–70 °C and were characterised by scanning electron microscopy, energy X-ray dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Their stoichiometry depends on the bath composition and applied potential. EDS and XRD patterns indicate the possible synthesis of stoichiometric Sb{sub 2}Te{sub 3} phase and Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, and Cu{sub 2.8}Te{sub 2} phases, respectively, by controlling the ratio of ion concentrations in ionic liquid electrolytes and deposition potential. - Highlights: • Sb{sub x}Te{sub y} and Cu{sub x}Te{sub y} films electrodeposited from choline-chloride-based ionic liquids. • The stoichiometry of film depends on the bath composition and deposition potential. • Sb{sub 2}Te{sub 3}, Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, Cu{sub 2.8}Te{sub 2} phases were identified in X-ray diffraction patterns.

  8. Comparative Study of Semiconductors Bismuth Iodate, Bismuth Triiodide and Bismuth Trisulphide Crystals

    Directory of Open Access Journals (Sweden)

    T.K. Patil

    2012-12-01

    Full Text Available In the present investigation, crystals of Bismuth Iodate[Bi(IO33], Bismuth Iodide[BiI3] and Bismuth- Tri Sulphide [Bi2S3] were grown by a simple gel technique using single diffusion method. The optimum growth conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of reactant etc. Gel was prepared by mixing sodium meta silicate (Na2SiO35H2O, glacial acetic acid (CH3COOH and supernant bismuth chloride (BiCl3 at pH value 4.4 and transferred in glass tube of diameter 2.5 cm and 25 cm in length. The mouth of test tube was covered by cotton plug and kept it for the setting. After setting the gel, it was left for aging. After 13 days duration the second supernant K(IO3, KI3 and H2S water gas solution was poured over the set gel by using pipette then it was kept undisturbed. After 72 hours of pouring the second supernatant, the small nucleation growth was observed at below the interface of gel. The good quality crystals of [Bi(IO33], [BiI3] and [Bi2S3] were grown. These grown crystals were characterized by XRD, FTIR, Chemical Analysis and Electrical Conductivity.

  9. Optical Constants of Cadmium Telluride Thin Film

    Science.gov (United States)

    Nithyakalyani, P.; Pandiaraman, M.; Pannir, P.; Sanjeeviraja, C.; Soundararajan, N.

    2008-04-01

    Cadmium Telluride (CdTe) is II-VI direct band gap semiconductor compound with potential application in Solar Energy conversion process. CdTe thin film of thickness 220 mn was prepared by thermal evaporation technique at a high vacuum better than 10-5 m.bar on well cleaned glass substrates of dimensions (l cm×3 cm). The transmittance spectrum and the reflectance spectrum of the prepared CdTc thin film was recorded using UV-Vis Spectrophotometer in the wavelength range between 300 nm and 900 nm. These spectral data were analyzed and the optical band and optical constants of CdTe Thin film have been determined by adopting suitable relations. The optical band gap of CdTe thin film is found to be 1.56 eV and this value is also agreeing with the published works of CdTe thin film prepared by various techniques. The absorption coefficient (α) has been higher than 106 cm-1. The Refractive index (n) and the Extinction Coefficient (k) are found to be varying from 3.0 to 4.0 and 0.1 Cm-1 to 0.5 Cm-1 respectively by varying the energy from l.0 eV to 4.0 eV. These results are also compared with the literature.

  10. Hydrothermal synthesis of bismuth germanium oxide

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Bismuth absorption from sup 205 Bi-labelled pharmaceutical bismuth compounds used in the treatment of peptic ulcer disease

    Energy Technology Data Exchange (ETDEWEB)

    Dresow, B.; Fischer, R.; Gabbe, E.E.; Wendel, J.; Heinrich, H.C. (Eppendorf University Hospital, Hamburg (Germany))

    1992-04-01

    The absorption of bismuth from five {sup 205}Bi-labelled pharmaceutically used bismuth compounds was studied in man. From single oral doses of all compounds under investigation only <0.1% bismuth was absorbed and excreted with the urine. A significantly higher absorption was observed from the colloidal bismuth subcitrate and the basic bismuth gallate than from the basic bismuth salicylate, nitrate and aluminate. No retention of bismuth in the whole body was found from the single dose experiment. The biologic fast-term half-lives of absorbed bismuth were calculated to be 0.12 and 1.5 days. 14 refs., 2 figs., 1 tab.

  12. Structure of unsupported bismuth nanoparticles

    Science.gov (United States)

    Wurl, A.; Hyslop, M.; Brown, S. A.; Hall, B. D.; Monot, R.

    We present new results of electron diffraction experiments on unsupported nanometer-sized bismuth clusters. The high intensity cluster beam, necessary for electron diffraction, is provided by an inert-gas aggregation source. The cluster beam contains particles with average cluster sizes between 4.5 and 10 nm. When using Helium as a carrier gas we are able to observe a transition from crystalline clusters to a new structure, which we identify with that of amorphous or liquid clusters.

  13. Ranitidine bismuth citrate: A review

    Directory of Open Access Journals (Sweden)

    N Chiba

    2001-01-01

    Full Text Available Recognition of the relationship between Helicobacter pylori infection and the development of gastroduodenal disease has increased greatly in recent years. To avoid complications of H pylori infection, such as the development of recurrent duodenal and gastric ulcers, effective therapies are required for eradication of the infection. This article reviews ranitidine bismuth citrate (RBC, a novel complex of ranitidine, bismuth and citrate, which was developed specifically for the purpose of eradicating H pylori. Dual therapy with RBC in combination with clarithromycin for 14 days yields eradication rates of 76%. Triple therapy bid for one week with a proton pump inhibitor, clarithromycin and either amoxicillin or a nitroimidazole (tinidazole or metronidazole is advocated as the treatment of choice for H pylori eradication. Analogous regimens with RBC in place of proton pump inhibitors show effective eradication rates in comparative studies and with pooled data. RBC, used alone or in combination with other antibiotics, appears to be a safe and effective drug for the treatment of H pylori infection. Bismuth levels do not appear to rise to toxic levels.

  14. In vitro cytotoxicity of surface modified bismuth nanoparticles.

    Science.gov (United States)

    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.

  15. High-temperature thermoelectric behavior of lead telluride

    Indian Academy of Sciences (India)

    M P Singh; C M Bhandari

    2004-06-01

    Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the degrading effect of minority carrier conduction. Lead telluride is among the best-known materials for use in the temperature range 400—900 K. This paper presents a detailed theoretical investigation of the role of minority carriers in degrading the thermoelectric properties of lead telluride and outlines the temperature range for optimal performance.

  16. Unconventional temperature enhanced magnetism in iron telluride

    Energy Technology Data Exchange (ETDEWEB)

    Zalinznyak, I. [Brookhaven National Laboratory (BNL); Xu, Zhijun [ORNL; Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Tsvelik, A. [Brookhaven National Laboratory (BNL); Stone, Matthew B [ORNL

    2011-01-01

    Discoveries of copper and iron-based high-temperature superconductors (HTSC)1-2 have challenged our views of superconductivity and magnetism. Contrary to the pre-existing view that magnetism, which typically involves localized electrons, and superconductivity, which requires freely-propagating itinerant electrons, are mutually exclusive, antiferromagnetic phases were found in all HTSC parent materials3,4. Moreover, highly energetic magnetic fluctuations, discovered in HTSC by inelastic neutron scattering (INS) 5,6, are now widely believed to be vital for the superconductivity 7-10. In two competing scenarios, they either originate from local atomic spins11, or are a property of cooperative spin-density-wave (SDW) behavior of conduction electrons 12,13. Both assume clear partition into localized electrons, giving rise to local spins, and itinerant ones, occupying well-defined, rigid conduction bands. Here, by performing an INS study of spin dynamics in iron telluride, a parent material of one of the iron-based HTSC families, we have discovered that this very assumption fails, and that conduction and localized electrons are fundamentally entangled. In the temperature range relevant for the superconductivity we observe a remarkable redistribution of magnetism between the two groups of electrons. The effective spin per Fe at T 10 K, in the2 antiferromagnetic phase, corresponds to S 1, consistent with the recent analyses that emphasize importance of Hund s intra-atomic exchange15-16. However, it grows to S 3/2 in the disordered phase, a result that profoundly challenges the picture of rigid bands, broadly accepted for HTSC.

  17. Microwave-assisted synthesis of bismuth oxide

    Directory of Open Access Journals (Sweden)

    Eva Bartonickova

    2007-12-01

    Full Text Available Single phase and ultrafine bismuth oxide was synthesized via microwave-assisted hydrothermal synthesis. The effect of reaction parameters (temperature/pressure and pH on the product phase composition and morphology was discussed. The transformation of bismuth hydroxide into bismuth oxide was controlled by pH value and it was accelerated by time and temperature. The phase composition of reaction products was strongly dependent on pH value. The amorphous products were obtained at acidic pH conditions and the crystalline single phase product α-Bi2O3 phase was obtained at pH ≥12. The particle size was reduced from micrometric to nanometric size in the presence of a chelating agent. The bismuth hydroxides into bismuth oxides transformation mechanism, consisting in polycondensation ofBi–OH bounds to Bi–O–Bi bridges and crystallization of Bi2O3, was proposed.

  18. Bismuth ions are metabolized into autometallographic traceable bismuth-sulphur quantum dots

    Directory of Open Access Journals (Sweden)

    M Stoltenberg

    2009-06-01

    Full Text Available Bismuth – sulphur quantum dots can be silver enhanced by autometallography (AMG. In the present study, autometallographic silver enhanced bismuth-sulphur nanocrystals were isolated from unfixed cryo-sections of kidneys and livers of rats exposed to bismuth (Bi207 subnitrate. After being subjected to AMG all the organic material was removed by sonication and enzymatic digestion and the silver enhanced Bi- S quantum dots spun down by an ultracentrifuge and analyzed by scintillation. The analysis showed that the autometallographic technique traces approximately 94% of the total bismuth. This implies that the injected bismuth is ultimately captured in bismuthsulphur quantum dots, i.e., that Bi-S nanocrystals are the end product of bismuth metabolism

  19. Thin films and solar cells of cadmium telluride and cadmium zinc telluride

    Science.gov (United States)

    Ferekides, Christos Savva

    The objectives of this dissertation are to investigate (1) the metalorganic chemical vapor deposition (MOCVD) and properties of cadmium telluride (CdTe) and cadmium zinc telluride (Cd(1-x)Zn(z)Te) films and junctions, and their potential application to solar cells, and (2) the fabrication and characterization of CdTe solar cells by the close spaced sublimation (CSS) technique. CdTe and Cd(1-x)Zn(x)Te films have been deposited by MOCVD on a variety of substrates at 300-400 C. The effect of the deposition parameters and post deposition heat treatments on the electrical, optical, and structural properties have been investigated. Heterojunctions of the configuration CdTe/transparent conducting semiconductor (TCS) and Cd(1-x)Zn(x)Te/TCS have been prepared and characterized. CdTe(MOCVD)/CdS and Cd(1-x)Zn(x)Te(E sub g = 1.65eV)/Cd(1-x)Zn(x)S solar cells with efficiencies of 9.9 percent and 2.4 percent, respectively have been fabricated. The as-deposited CdTe(MOCVD)/CdS junctions exhibited high dark current densities due to deflects at the interface associated with small grain size. Their characteristics of the Cd(1-x)Zn(x)Te junctions degraded with increasing Zn concentration due to the crystalline quality and very small grain size (0.3 microns) in films with high ZnTe contents (greater than 25 percent). No effective post-deposition heat treatment has been developed. CdTe/CdS solar cells have also been fabricated by the close spaced sublimation (CSS). Significant improvements in material and processing have been made, and in collaboration with fellow researchers an AM1.5 conversion efficiency of 13.4 percent has been demonstrated, the highest efficiency ever measured for such devices. The highest conversion efficiency for the CdTe(CSS)/CdS solar cell was achieved by reaching high open-circuit voltages and fill factors, while the short-circuit current densities were moderate. These results indicate that further improvements to increase the short-circuit current densities

  20. Preparation of Strontium Bismuth Tantalum (SBT) Fine Powder by Sol-Gel Process Using Bismuth Subnitrate as Bismuth Source

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Strontium bismuth tantalum (SBT) fine power was prepared by Sol-Gel method. Pentaethoxy tantalum, strontium acetate and bismuth subnitrate were used as raw materials, and were dissolved in proper order in ethylene glycol to form transparent sol. The mixed precursor was dried at 80°C and annealed at 800°C for 1 h. Crystallized nanometer sized SBT fine powder was obtained and characterized by XRD.

  1. Electrochemical properties of porous bismuth electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Romann, T., E-mail: tavo.romann@ut.e [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Lust, E. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia)

    2010-08-01

    The properties of Bi surfaces with different roughnesses were characterized by electron microscopy, cyclic voltammetry, and impedance spectroscopy. Two different strategies were used for preparation of porous bismuth layers onto Bi microelectrode surface in aqueous 0.1 M LiClO{sub 4} solution. Firstly, treatment at potential E < -2 V (vs. Ag|AgCl in sat. KCl) has been applied, resulting in bismuth hydride formation and decomposition into Bi nanoparticles which deposit at the electrode surface. Secondly, porous Bi layer was prepared by anodic dissolution (E = 1 V) of bismuth electrode followed by fast electroreduction of formed Bi{sup 3+} ions at cathodic potentials E = -2 V. The nanostructured porous bismuth electrode, with surface roughness factor up to 220, has negligible frequency dispersion of capacitance and higher hydrogen evolution overvoltage than observed for smooth Bi electrodes.

  2. Thermoelectric properties of pressed bismuth nanoparticles

    Science.gov (United States)

    Hostler, Stephen R.; Qu, Yu Qiao; Demko, Michael T.; Abramson, Alexis R.; Qiu, Xiaofeng; Burda, Clemens

    2008-03-01

    Theory predicts a substantial increase in the dimensionless figure of merit as the dimensionality and characteristic size of a material are decreased. We explore the use of bismuth nanoparticles pressed into pellets as potential increased efficiency thermoelectric materials. The figure of merit of these pellets is determined by independently measuring the electrical conductivity, thermal conductivity and Seebeck coefficient. The results from the nanoparticle sample are compared to microparticle-based samples. Both sample types show a slight reduction in thermal conductivity relative to bulk bismuth and a Seebeck coefficient near or slightly larger in magnitude than bulk bismuth. These changes are dwarfed by a hundred-fold decrease in the electrical conductivity due to porosity and an oxide layer on the particles. The low conductivity leads to figures of merit at least two orders of magnitude smaller than bulk bismuth. Oxide layer removal and reduced pellet porosity will be required to increase the figure of merit.

  3. Kelvin Probe Studies of Cesium Telluride Photocathode for AWA Photoinjector

    CERN Document Server

    Wisniewski, Eric; Yusof, Zikri; Spentzouris, Linda; Terry, Jeff; Harkay, Katherine

    2012-01-01

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (~50 nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  4. The Cadmium Zinc Telluride Imager on AstroSat

    CERN Document Server

    Bhalerao, V; Vibhute, A; Pawar, P; Rao, A R; Hingar, M K; Khanna, Rakesh; Kutty, A P K; Malkar, J P; Patil, M H; Arora, Y K; Sinha, S; Priya, P; Samuel, Essy; Sreekumar, S; Vinod, P; Mithun, N P S; Vadawale, S V; Vagshette, N; Navalgund, K H; Sarma, K S; Pandiyan, R; Seetha, S; Subbarao, K

    2016-01-01

    The Cadmium Zinc Telluride Imager (CZTI) is a high energy, wide-field imaging instrument on AstroSat. CZT's namesake Cadmium Zinc Telluride detectors cover an energy range from 20 keV to > 200 keV, with 11% energy resolution at 60 keV. The coded aperture mask attains an angular resolution of 17' over a 4.6 deg x 4.6 deg (FWHM) field of view. CZTI functions as an open detector above 100 keV, continuously sensitive to GRBs and other transients in about 30% of the sky. The pixellated detectors are sensitive to polarisation above ~100 keV, with exciting possibilities for polarisation studies of transients and bright persistent sources. In this paper, we provide details of the complete CZTI instrument, detectors, coded aperture mask, mechanical and electronic configuration, as well as data and products.

  5. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells. Final subcontract report, 1 July 1988--31 December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L. [University of South Florida, Tampa, FL (United States)

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

  6. Gamma-ray peak shapes from cadmium zinc telluride detectors

    Energy Technology Data Exchange (ETDEWEB)

    Namboodiri, M.N.; Lavietes, A.D.; McQuaid, J.H.

    1996-09-01

    We report the results of a study of the peak shapes in the gamma spectra measured using several 5 x 5 x 5 mm{sup 3} cadmium zinc telluride (CZT) detectors. A simple parameterization involving a Gaussian and an exponential low energy tail describes the peak shapes sell. We present the variation of the parameters with gamma energy. This type of information is very useful in the analysis of complex gamma spectra consisting of many peaks.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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. Liquid Bismuth Propellant Flow Sensor

    Science.gov (United States)

    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

  11. Harnessing Topological Band Effects in Bismuth Telluride Selenide for Large Enhancements in Thermoelectric Properties through Isovalent Doping.

    Science.gov (United States)

    Devender; Gehring, Pascal; Gaul, Andrew; Hoyer, Alexander; Vaklinova, Kristina; Mehta, Rutvik J; Burghard, Marko; Borca-Tasciuc, Theodorian; Singh, David J; Kern, Klaus; Ramanath, Ganpati

    2016-08-01

    Dilute isovalent sulfur doping simultaneously increases electrical conductivity and Seebeck coefficient in Bi2 Te2 Se nanoplates, and bulk pellets made from them. This unusual trend at high electron concentrations is underpinned by multifold increases in electron effective mass attributable to sulfur-induced band topology effects, providing a new way for accessing a high thermoelectric figure-of-merit in topological-insulator-based nanomaterials through doping.

  12. Photobleaching effect in bismuth-doped germanosilicate fibers.

    Science.gov (United States)

    Firstov, Sergei; Alyshev, Sergey; Khopin, Vladimir; Melkumov, Mikhail; Guryanov, Alexey; Dianov, Evgeny

    2015-07-27

    Photoinduced reduction of absorption (photobleaching) in bismuth-doped germanosilicate fibers irradiated with 532-nm laser has been observed for the first time. It was demonstrated that bismuth-related active centers having the absorption bands at wavelengths of 1400 and 1700 nm degrade under photoexcitation at 532 nm. The photobleaching process rate was estimated using conventional stretched exponential technique. It was found that the photobleaching rate in bismuth-doped germanosilicate fibers does not depend on type of bismuth-related active center. The possible underlying mechanism of photobleaching process in bismuth-doped fibers is discussed.

  13. Origin of anomalous anharmonic lattice dynamics of lead telluride

    CERN Document Server

    Shiga, Takuma; Hori, Takuma; Delaire, Olivier; Shiomi, Junichiro

    2015-01-01

    The origin of the anomalous anharmonic lattice dynamics of lead telluride is investigated using molecular dynamics simulations with interatomic force constants (IFCs) up to quartic terms obtained from first principles. The calculations reproduce the peak asymmetry of the radial distribution functions and the double peaks of transverse optical phonon previously observed with neutron diffraction and scattering experiments. They are identified to be due to the extremely large nearest-neighbor cubic IFCs in the [100] direction. The outstanding strength of the nearest-neighbor cubic IFCs relative to the longer-range ones explains the reason why the distortion in the radial distribution function is local.

  14. Hyperfine splitting in lithium-like bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Lochmann, Matthias; Froemmgen, Nadja; Hammen, Michael; Will, Elisa [Universitaet Mainz (Germany); Andelkovic, Zoran; Kuehl, Thomas; Litvinov, Yuri; Winters, Danyal; Sanchez, Rodolfo [GSI Helmholtzzentrum, Darmstadt (Germany); Botermann, Benjamin; Noertershaeuser, Wilfried [Technische Universitaet Darmstadt (Germany); Bussmann, Michael [Helmholtzzentrum Dresden-Rossendorf (Germany); Dax, Andreas [CERN, Genf (Switzerland); Hannen, Volker; Joehren, Raphael; Vollbrecht, Jonas; Weinheimer, Christian [Universitaet Muenster (Germany); Geppert, Christopher [Universitaet Mainz (Germany); GSI Helmholtzzentrum, Darmstadt (Germany); Stoehlker, Thomas [GSI Helmholtzzentrum, Darmstadt (Germany); Universitaet Heidelberg (Germany); Thompson, Richard [Imperial College, London (United Kingdom); Volotka, Andrey [Technische Universitaet Dresden (Germany); Wen, Weiqiang [IMP Lanzhou (China)

    2013-07-01

    High-precision measurements of the hyperfine splitting values on Li- and H-like bismuth ions, combined with precise atomic structure calculations allow us to test QED-effects in the regime of the strongest magnetic fields that are available in the laboratory. Performing laser spectroscopy at the experimental storage ring (ESR) at GSI Darmstadt, we have now succeeded in measuring the hyperfine splitting in Li-like bismuth. Probing this transition has not been easy because of its extremely low fluorescence rate. Details about this challenging experiment will be given and the achieved experimental accuracy are presented.

  15. Burnout current density of bismuth nanowires

    Science.gov (United States)

    Cornelius, T. W.; Picht, O.; Müller, S.; Neumann, R.; Völklein, F.; Karim, S.; Duan, J. L.

    2008-05-01

    Single bismuth nanowires with diameters ranging from 100nmto1μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density the wires are able to carry was investigated by ramping up the current until failure occurred. It increases by three to four orders of magnitude for nanowires embedded in the template compared to bulk bismuth and rises with diminishing diameter. Simulations show that the wires are heated up electrically to the melting temperature. Since the surface-to-volume ratio rises with diminishing diameter, thinner wires dissipate the heat more efficiently to the surrounding polymer matrix and, thus, can tolerate larger current densities.

  16. Bismuth titanate nanorods and their visible light photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.Z., E-mail: lzpei@ahut.edu.cn; Liu, H.D.; Lin, N.; Yu, H.Y.

    2015-02-15

    Highlights: • Bismuth titanate nanorods have been synthesized by a simple hydrothermal process. • The size of bismuth titanate nanorods can be controlled by growth conditions. • Bismuth titanate nanorods show good photocatalytic activities of methylene blue and Rhodamine B. - Abstract: Bismuth titanate nanorods have been prepared using a facile hydrothermal process without additives. The bismuth titanate products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and UV-vis diffusion reflectance spectrum. XRD pattern shows that the bismuth titanate nanorods are composed of cubic Bi{sub 2}Ti{sub 2}O{sub 7} phase. Electron microscopy images show that the length and diameter of the bismuth titanate nanorods are 50-200 nm and 2 μm, respectively. Hydrothermal temperature and reaction time play important roles on the formation and size of the bismuth titanate nanorods. UV-vis diffusion reflectance spectrum indicates that bismuth titanate nanorods have a band gap of 2.58 eV. The bismuth titanate nanorods exhibit good photocatalytic activities in the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RB) under visible light irradiation. The bismuth titanate nanorods with cubic Bi{sub 2}Ti{sub 2}O{sub 7} phase are a promising candidate as a visible light photocatalyst.

  17. Kelvin probe studies of cesium telluride photocathode for AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, Eric E., E-mail: ewisniew@anl.gov [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Velazquez, Daniel [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Yusof, Zikri, E-mail: zyusof@hawk.iit.edu [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Spentzouris, Linda; Terry, Jeff [Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Sarkar, Tapash J. [Rice University, 6100 Main, Houston, TX 77005 (United States); Harkay, Katherine [Accelerator Science Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States)

    2013-05-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (≈50nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating. -- Highlights: ► The correlation between Quantum Efficiency (QE) and work function. ► How QE and work function evolve together. ► Rejuvenation of the photocathode via heating and the effect on work function. ► The effects on the work function due to exposure to UV light.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Smita; Rajendra, Ranguwar; Ballav, Nirmalya; Kulkarni, Sulabha, E-mail: s.kulkarni@iiserpune.ac.in [Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008 (India); Sarkar, Indranil [DESY Photon Science, Deutsches Elektronen-Synchrotron, 22607 Hamburg (Germany); Shirolkar, Mandar M. [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Jeng, U-Ser; Yeh, Yi-Qi [National Synchrotron Radiation Research Center, 101, Hsin-Ann Road, Science Park, Hsinchu 3007-6, Taiwan (China)

    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 phosphates as intermediate temperature proton conductors

    DEFF Research Database (Denmark)

    Huang, Yunjie; Christensen, Erik; Shuai, Qin

    2016-01-01

    Proton conducting electrolyte materials operational in the intermediate temperature range of 200-400 °C are of special interest for applications in fuel cells and water electrolysers. Bismuth phosphates in forms of polycrystalline powders and amorphous glasses are synthesized and investigated...

  20. Development and Investigation of Bismuth Nanowires

    Science.gov (United States)

    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

  1. Effect of Lipophilic Bismuth Nanoparticles on Erythrocytes

    Directory of Open Access Journals (Sweden)

    Rene Hernandez-Delgadillo

    2015-01-01

    Full Text Available Lipophilic bismuth dimercaptopropanol nanoparticles (BisBAL NPs have a very important antimicrobial activity; however their effect on human cells or tissues has not been completely studied. Undesirable effects of bismuth include anemia which could result from suicidal erythrocyte death or eryptosis. The objective of this research was to determine the effect of bismuth dimercaptopropanol nanoparticles on blood cells. The nanoparticles are composed of 53 nm crystallites on average and have a spherical structure, agglomerating into clusters of small nanoparticles. Based on cell viability assays and optical microscopy, cytotoxicity on erythrocytes was observed after growing with 500 and 1000 µM of BisBAL NPs for 24 h. AM Calcein was retained inside erythrocytes when they were exposed to 100 µM (or lower concentrations of BisBAL NPs for 24 h, suggesting the absence of damage in plasmatic membrane. Genotoxic assays revealed no damage to genomic DNA of blood cells after 24 h of exposition to BisBAL NPs. Finally, 100–1000 µM of bismuth nanoparticles promotes apoptosis between blood cells after 24 h of incubation. Hence BisBAL NPs at concentrations lower than 100 µM do not cause damage on blood cells; they could potentially be used by humans without affecting erythrocytes and leukocytes.

  2. Effect of metallic coatings on thermoelectric properties of lead telluride films

    Energy Technology Data Exchange (ETDEWEB)

    Ukhlinov, G.A.; Lakhno, I.G. (Moskovskij Inst. Ehlektronnoj Tekhniki (USSR))

    1984-05-01

    Effect of sprayed coatings of different metals on thermoelectric properties of lead telluride films was investigated. The basic films were prepared by the method of vacuum thermal evaporation of sample of stoichiometric lead telluride at 5x10/sup -4/ Pa residual pressure on mica (muscovite) sublayer at 330-350 deg C and approximately 10 nm/s deposition rate. It was established that fine coatings of copper, silver and gold modify sufficiently electric properties of lead telluride films. The effect is conditioned mainly by decoration and electric shunting of grain boundaries by metal island, which removes the contribution of grain boundaries to film electric conductivity.

  3. Synthesis of 1,3-diynes via detelluration of bis(ethynyl)tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Stefani, Helio A.; PenaI, Jesus M. [Universidade de Sao Paulo (FCF/USP), SP (Brazil). Fac. de Ciencias Farmaceuticas; Zukerman-Schpector, Julio [Universidade Federal de Sao Carlos (DQ/UFSCar), SP (Brazil). Dept. de Quimica; Tiekink, Edward R.T. [University of Malaya, Kuala Lumpur (Malaysia). Dept. of Chemistry

    2011-07-01

    The synthesis of symmetric conjugated diyne systems with electron-withdrawing or electron-donating substituents via a palladium-catalyzed detelluration of bis(arylethynyl)tellurides and bis(alkylethynyl)tellurides is described. This procedure is effected under atmospheric conditions in DMF using Pd(OAc)2 as a catalyst and AgOAc as an additive in the presence of triethylamine. This route offers efficient access to conjugated diyne systems in short reaction time. X-ray crystallographic structure and solid-state conformation of bis(p-tolylethynyl)telluride show a supramolecular chain aligned along the b axis, sustained by C-H...p interactions. (author)

  4. Cadmium Telluride-Titanium Dioxide Nanocomposite for Photodegradation of Organic Substance.

    Science.gov (United States)

    Ontam, Areeporn; Khaorapapong, Nithima; Ogawa, Makoto

    2015-12-01

    Cadmium telluride-titanium dioxide nanocomposite was prepared by hydrothermal reaction of sol-gel derived titanium dioxide and organically modified cadmium telluride. The crystallinity of titanium dioxide in the nanocomposite was higher than that of pure titanium dioxide obtained by the reaction under the same temperature and pressure conditions, showing that cadmium telluride induced the crystallization of titanium dioxide. Diffuse reflectance spectrum of the nanocomposite showed the higher absorption efficiency in the UV-visible region due to band-gap excitation of titanium dioxide. The nanocomposite significantly showed the improvement of photocatalytic activity for 4-chlorophenol with UV light.

  5. Megapixel mercury cadmium telluride focal plane arrays for infrared imaging out to 12 microns Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the fabrication of large format, long wave infrared (LWIR) mercury cadmium telluride (HgCdTe or MCT) detector arrays where the cutoff wavelength is...

  6. Bismuth( Ⅲ ) Salts: Green Catalysts for Organic Transformations

    Institute of Scientific and Technical Information of China (English)

    C. Le Roux

    2005-01-01

    @@ 1Introduction Bismuth, the heaviest stable element in the periodic table, stands out from other heavy elements (such as mercury, thallium and lead) due to its relatively non-toxic character which confers on bismuth the enviable status of being an eco-friendly element. Therefore, bismuth and its compounds hold considerable promise as useful catalysts for green chemistry. The research presented in this communication is devoted to the applications of bismuth( Ⅲ ) salts as catalysts for organic transformations.After some general comments about bismuth and a short presentation of the various applications of bismuth( Ⅲ ) salts in organic synthesis, this communication will focus on the works done in our research group during the last several years which deals mainly with electrophilic substitutions. When appropriate, some mechanistic details will be given.

  7. Electrochemical Studies of Lead Telluride Behavior in Acidic Nitrate Solutions

    Directory of Open Access Journals (Sweden)

    Rudnik E.

    2015-04-01

    Full Text Available Electrochemistry of lead telluride stationary electrode was studied in nitric acid solutions of pH 1.5-3.0. E-pH diagram for Pb-Te-H2O system was calculated. Results of cyclic voltammetry of Pb, Te and PbTe were discussed in correlation with thermodynamic predictions. Anodic dissolution of PbTe electrode at potential approx. -100÷50 mV (SCE resulted in tellurium formation, while above 300 mV TeO2 was mainly produced. The latter could dissolve to HTeO+2 under acidic electrolyte, but it was inhibited by increased pH of the bath.

  8. Structural properties of oxygenated amorphous cadmium telluride thin films

    Energy Technology Data Exchange (ETDEWEB)

    El Azhari, M.Y. [Laboratoire de Physique des Solides et des Couches Minces, Marakech (Morocco). Dept. de Physique; Azizan, M. [Laboratoire de Physique des Solides et des Couches Minces, Marakech (Morocco). Dept. de Physique; Bennouna, A. [Laboratoire de Physique des Solides et des Couches Minces, Marakech (Morocco). Dept. de Physique; Outzourhit, A. [Laboratoire de Physique des Solides et des Couches Minces, Marakech (Morocco). Dept. de Physique; Ameziane, E.L. [Laboratoire de Physique des Solides et des Couches Minces, Marakech (Morocco). Dept. de Physique; Brunel, M. [Laboratoire de Cristallographie, CNRS, Grenoble (France)

    1997-02-28

    Cadmium telluride (CdTe) thin films were prepared by diode radio-frequency sputtering from polycrystalline CdTe targets in an atmosphere of argon, nitrogen and oxygen. The layers prepared in the presence of nitrogen gas were amorphous and their oxygen contents increased with the partial pressure of nitrogen. The evolution of the composition of the layers as a function of the nitrogen partial pressure during deposition was followed by X-ray photoelectron spectroscopy. It is found that the oxygen is bound to both tellurium and cadmium atoms. The surface of the CdTe thin films was also studied as a function of their exposure time to a plasma containing a mixture of nitrogen and oxygen. It is found that the oxygen contents of the surface increases with increased exposure time. Also, this exposure resulted in an increase of the oxide thickness and a net decrease in the surface roughness of the films. (orig.)

  9. Mercury Cadmium Telluride Photoconductive Long Wave Infrared Linear Array Detectors

    Directory of Open Access Journals (Sweden)

    Risal Singh

    2003-07-01

    Full Text Available Mercury cadmium telluride (Hg1-x, CdxTe (MCT photoconductive long wave infrared linear arrays are still in demand due to several advantages. The linear array technology is well established, easier, economical and is quite relevant to thermal imaging even today. The scan thermal imaging systems based on this technology offer wider field of view coverage and capacity for higher resolution in the scan direction relative to staring systems that use expensive and yet to mature focal plane array detector technology. A critical review on photoconductive n-Hg1-x CdxTe linear array detector technology for the long wave infrared range has been presented. The emphasis lies on detector design and processing technology. The critical issues of diffusion and drift effects, Hi-Lo and heterostructure blocking contacts, surface passivation, and other related aspects have been considered from the detector design angle. The device processing technology aspects are of vital importance

  10. Photosensitive cadmium telluride thin-film field-effect transistors.

    Science.gov (United States)

    Yang, Gwangseok; Kim, Donghwan; Kim, Jihyun

    2016-02-22

    We report on the graphene-seeded growth and fabrication of photosensitive Cadmium telluride (CdTe)/graphene hybrid field-effect transistors (FETs) subjected to a post-growth activation process. CdTe thin films were selectively grown on pre-defined graphene, and their morphological, electrical and optoelectronic properties were systemically analyzed before and after the CdCl2 activation process. CdCl2-activated CdTe FETs showed p-type behavior with improved electrical features, including higher electrical conductivity (reduced sheet resistance from 1.09 × 10(9) to 5.55 × 10(7) Ω/sq.), higher mobility (from 0.025 to 0.20 cm2/(V·s)), and faster rise time (from 1.23 to 0.43 s). A post-growth activation process is essential to fabricate high-performance photosensitive CdTe/graphene hybrid devices.

  11. Growth of lead-tin telluride crystals under high gravity

    Science.gov (United States)

    Regel, L. L.; Turchaninov, A. M.; Shumaev, O. V.; Bandeira, I. N.; An, C. Y.; Rappl, P. H. O.

    1992-04-01

    The influence of high gravity environment on several growth habits of lead-tin telluride crystals began to be investigated. Preliminary experiments with Pb 0.8Sn 0.2te grown by the Bridgman technique had been made at the centrifuge facilities of the Y.A. Gagarin Cosmonauts Center in the USSR, using accelerations of 5 g, 5.2 g and 8 g. The Sn distribution for these crystals was compared with that obtained for growth at normal gravity and the results show the existence of significant compositional inhomogeneities along the axial direction. Convection currents at high gravity seem to help multiple nucleation and subsequent random orientation of growth. Analyses of carrier concentrations as well as morphological characteristics were also made.

  12. Study on thermal annealing of cadmium zinc telluride (CZT) crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.; Bolotnikov, A.E.; Fochuk, P.M.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.; Horace, J.; McCall, B.; Gul, R.; Xu, L.; Kopach, O.V.; and James, R.B.

    2010-08-01

    Cadmium Zinc Telluride (CZT) has attracted increasing interest with its promising potential as a room-temperature nuclear-radiation-detector material. However, different defects in CZT crystals, especially Te inclusions and dislocations, can degrade the performance of CZT detectors. Post-growth annealing is a good approach potentially to eliminate the deleterious influence of these defects. At Brookhaven National Laboratory (BNL), we built up different facilities for investigating post-growth annealing of CZT. Here, we report our latest experimental results. Cd-vapor annealing reduces the density of Te inclusions, while large temperature gradient promotes the migration of small-size Te inclusions. Simultaneously, the annealing lowers the density of dislocations. However, only-Cd-vapor annealing decreases the resistivity, possibly reflecting the introduction of extra Cd in the lattice. Subsequent Te-vapor annealing is needed to ensure the recovery of the resistivity after removing the Te inclusions.

  13. Cadmium Telluride Solar Cells with PEDOT:PSS Back Contact

    Science.gov (United States)

    Mount, Michael; Duarte, Fernanda; Paudel, Naba; Yan, Yanfa; Wang, Weining

    Cadmium Telluride (CdTe) solar cell is one of the most promising thin film solar cells and its highest efficiency has reached 21%. To keep improving the efficiency of CdTe solar cells, a few issues need to be addressed, one of which is the back contact. The back contact of CdTe solar cells are mostly Cu-base, and the problem with Cu-based back contact is that Cu diffuses into the grain boundary and into the CdS/CdTe junction, causing degradation problem at high temperature and under illumination. To continue improving the efficiency of CdTe/CdS solar cells, a good ohmic back contact with high work function and long term stability is needed. In this work, we report our studies on the potential of conducting polymer being used as the back contact of CdTe/CdS solar cells. Conducting polymers are good candidates because they have high work functions and high conductivities, are easy to process, and cost less, meeting all the requirements of a good ohmic back contact for CdTe. In our studies, we used poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with different conductivities and compared them with traditional Cu-based back contact. It was observed that the CdTe solar cell performance improves as the conductivity of the PEDOT:PSS increase, and the efficiency (9.1%) is approaching those with traditional Cu/Au back contact (12.5%). Cadmium Telluride Solar Cells with PEDOT:PSS Back Contact.

  14. Electrical resistivity of thin bismuth films

    Science.gov (United States)

    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.

  15. Flame spray synthesis under a non-oxidizing atmosphere: Preparation of metallic bismuth nanoparticles and nanocrystalline bulk bismuth metal

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Robert N.; Stark, Wendelin J. [Institute for Chemical and Bioengineering, ETH Zuerich (Switzerland)], E-mail: wendelin.stark@chem.ethz.ch

    2006-10-15

    Metallic bismuth nanoparticles of over 98% purity were prepared by a modified flame spray synthesis method in an inert atmosphere by oxygen-deficient combustion of a bismuth-carboxylate based precursor. The samples were characterized by X-ray diffraction, thermal analysis and scanning electron microscopy confirming the formation of pure, crystalline metallic bismuth nanoparticles. Compression of the as-prepared powder resulted in highly dense, nanocrystalline pills with strong electrical conductivity and bright metallic gloss.

  16. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    OpenAIRE

    Zhouling Wang; Yu Hu; Wei Li; Guanggen Zeng; Lianghuan Feng; Jingquan Zhang; Lili Wu; Jingjing Gao

    2014-01-01

    Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was high...

  17. Factors affecting bismuth vanadate photoelectrochemical performance

    OpenAIRE

    Sinclair, Timothy S.; Hunter, Bryan M.; Winkler, Jay R.; Gray, Harry B.; Müller, Astrid M.

    2015-01-01

    Bismuth vanadate is a promising photoanode material, but recent reports on undoped BiVO_4 without sublayers and co-catalysts showed large variations in photocurrent generation. We addressed this issue by correlating photoelectrochemical performance with physical properties. We devised a novel anodic electrodeposition procedure with iodide added to the aqueous plating bath, which allowed us to prepare BiVO_4 photoanodes with virtually identical thicknesses but different morphologies, and we co...

  18. Electrocatalytic activity of bismuth doped silver electrodes

    CERN Document Server

    Amjad, M

    2002-01-01

    Investigation of redox reactions on silver, and bismuth doped silver electrodes in aqueous KOH solutions, by using potentiostatic steady-state polarization technique, has been carried out. The redox wave potential and current displacements along with multiplicity of the latter have been examined. These electrodes were employed for the oxidation of organic molecules such as ethylamine in alkaline media. Subsequently, these electrodes were ranked with respect to their activity for the redox reactions. (author)

  19. Efficient enhancement of bismuth NIR luminescence by aluminum and its mechanism in bismuth doped germanate laser glass

    DEFF Research Database (Denmark)

    Wang, L.P.; Tan, L.L.; Yue, Yuanzheng

    2016-01-01

    on how to improve the luminescence efficiency. Here, we demonstrate that addition of aluminum can enhance the bismuth near-infrared luminescence by more than 10 000 times, which is right followed by the discussion on the mechanism on why this can happen. We believe this work can be helpful for designing...... bismuth-doped multiple component laser glasses with high efficiency. In addition, because of high susceptibility of bismuth to local field change, it can be used as probe ion to envision glass structures. Using bismuth as a luminescent structural probe, we can see the modifier ions of Bi...

  20. Heat-Pipe Bismuth Laser; Examination of Laser Action at 4722A in Bismuth Vapor

    Science.gov (United States)

    1976-11-01

    transitions in other atomic vapors. 13. MODELING OF THE INITIAL BREAKDOWN PROCESS During the initial nanosecond after the fast thyratron switch closes suddenly...lasers computer modeling , laser kin etics bismuth vapor pressure and composition excitation cross sections bismuth dim ers e8ifn.eividienibbek 2Q...P3 / 2 " p $3/4 transi- 3/4 3/2 tion probability is at least a factor of 20 too low. Continuation of the computer modeling begun in this study could

  1. Structural relaxation in bismuth and lead borate glasses

    Science.gov (United States)

    Bajaj, Anu; Khanna, Atul

    2012-06-01

    Bismuth and lead borate glasses were prepared by melt quench technique. Effects of heat treatment on the density and thermal properties of bismuth and lead borate glasses was studied by annealing the glasses at 350°C for 500 h. Density of all bismuth borate glasses increases by about 0.5-0.7% with annealing and the effect is more in glasses with higher Bi2O3 concentration. In bismuth borate glasses with 50 and 55 mol % Bi2O3 we found an extraordinary large increase of Tg by 15°C after thermal annealing. All bismuth borate glasses remained completely clear and transparent on annealing. Lead borate glasses become cloudy on thermal annealing indicating occurrence of phase separation in these glasses.

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

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, Jasmine B. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Garje, Shivram S., E-mail: ssgarje@chem.mu.ac.in [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Nuwad, Jitendra; Pillai, C.G.S. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    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.

  3. Bismuth-Based Quadruple Therapy with Bismuth Subcitrate, Metronidazole, Tetracycline and Omeprazole in the Eradication of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Raymond Lahaie

    2001-01-01

    Full Text Available BACKGROUND: A previous study showed that 14 days of qid bismuth-based triple therapy with tetracycline 500 mg, metronidazole 250 mg and colloidal bismuth subcitrate 120 mg resulted in excellent Helicobacter pylori eradication rates (89.5%. The present study looked at a shorter treatment period by adding omeprazole and by reducing the dose of tetracycline.

  4. Frustrated square lattice Heisenberg model and magnetism in Iron Telluride

    Science.gov (United States)

    Zaliznyak, Igor; Xu, Zhijun; Gu, Genda; Tranquada, John; Stone, Matthew

    2011-03-01

    We have measured spin excitations in iron telluride Fe1.1Te, the parent material of (1,1) family of iron-based superconductors. It has been recognized that J1-J2-J3 frustrated Heisenberg model on a square lattice might be relevant for the unusual magnetism and, perhaps, the superconductivity in cuprates [1,2]. Recent neutron scattering measurements show that similar frustrated model might also provide reasonable account for magnetic excitations in iron pnictide materials. We find that it also describes general features of spin excitations in FeTe parent compound observed in our recent neutron measurements, as well as in those by other groups. Results imply proximity of magnetic system to the limit of extreme frustration. Selection of spin ground state under such conditions could be driven by weak extrinsic interactions, such as lattice distortion, or strain. Consequently, different nonuniversal types of magnetic order could arise, both commensurate and incommensurate. These are not necessarily intrinsic to an ideal J1-J2-J3 model, but might result from lifting of its near degeneracy by weak extrinsic perturbations.

  5. Thickness-induced structural phase transformation of layered gallium telluride.

    Science.gov (United States)

    Zhao, Q; Wang, T; Miao, Y; Ma, F; Xie, Y; Ma, X; Gu, Y; Li, J; He, J; Chen, B; Xi, S; Xu, L; Zhen, H; Yin, Z; Li, J; Ren, J; Jie, W

    2016-07-28

    The thickness-dependent electronic states and physical properties of two-dimensional materials suggest great potential applications in electronic and optoelectronic devices. However, the enhanced surface effect in ultra-thin materials might significantly influence the structural stability, as well as the device reliability. Here, we report a spontaneous phase transformation of gallium telluride (GaTe) that occurred when the bulk was exfoliated to a few layers. Transmission electron microscopy (TEM) results indicate a structural variation from a monoclinic to a hexagonal structure. Raman spectra suggest a critical thickness for the structural transformation. First-principle calculations and thermodynamic analysis show that the surface energy and the interlayer interaction compete to dominate structural stability in the thinning process. A two-stage transformation process from monoclinic (m) to tetragonal (T) and then from tetragonal to hexagonal (h) is proposed to understand the phase transformation. The results demonstrate the crucial role of interlayer interactions in the structural stability, which provides a phase engineering strategy for device applications.

  6. Brief review of cadmium telluride-based photovoltaic technologies

    Science.gov (United States)

    Başol, Bülent M.; McCandless, Brian

    2014-01-01

    Cadmium telluride (CdTe) is the most commercially successful thin-film photovoltaic technology. Development of CdTe as a solar cell material dates back to the early 1980s when ˜10% efficient devices were demonstrated. Implementation of better quality glass, more transparent conductive oxides, introduction of a high-resistivity transparent film under the CdS junction-partner, higher deposition temperatures, and improved Cl-treatment, doping, and contacting approaches yielded >16% efficient cells in the early 2000s. Around the same time period, use of a photoresist plug monolithic integration process facilitated the demonstration of the first 11% efficient module. The most dramatic advancements in CdTe device efficiencies were made during the 2013 to 2014 time frame when small-area cell conversion efficiency was raised to 20% range and a champion module efficiency of 17% was reported. CdTe technology is attractive in terms of its limited life-cycle greenhouse gas and heavy metal emissions, small carbon footprint, and short energy payback times. Limited Te availability is a challenge for the growth of this technology unless Te utilization rates are greatly enhanced along with device efficiencies.

  7. Using atomistic simulations to model cadmium telluride thin film growth

    Science.gov (United States)

    Yu, Miao; Kenny, Steven D.

    2016-03-01

    Cadmium telluride (CdTe) is an excellent material for low-cost, high efficiency thin film solar cells. It is important to conduct research on how defects are formed during the growth process, since defects lower the efficiency of solar cells. In this work we use computer simulation to predict the growth of a sputter deposited CdTe thin film. On-the-fly kinetic Monte Carlo technique is used to simulate the CdTe thin film growth on the (1 1 1) surfaces. The results show that on the (1 1 1) surfaces the growth mechanisms on surfaces which are terminated by Cd or Te are quite different, regardless of the deposition energy (0.1∼ 10 eV). On the Te-terminated (1 1 1) surface the deposited clusters first form a single mixed species layer, then the Te atoms in the mixed layer moved up to form a new layer. Whilst on the Cd-terminated (1 1 1) surface the new Cd and Te layers are formed at the same time. Such differences are probably caused by stronger bonding between ad-atoms and surface atoms on the Te layer than on the Cd layer.

  8. High efficiency thin film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, Shirley S.; Britt, J.; Chen, G.; Ferekides, C.; Schultz, N.; Wang, C.; Wu, C. Q.

    1992-12-01

    Cadmium sulfide (CdS), grown from an aqueous solution, and zinc oxide (ZnO), cadmium zinc sulfide (Cd1-xZnxS), and zinc selenide (ZnSe), deposited by metalorganic chemical vapor deposition (MOCVD), have been used as the window for thin film cadmium telluride (CdTe) solar cells. Thin film solar cells were prepared by the successive deposition of the window and p-CdTe (by MOCVD and close-spaced sublimation, CSS) on SnO2:F/glass substrates. CdS/CdTe(CSS) solar cells show considerably better characteristics than CdS/CdTe(MOCVD) solar cells because of the better microstructure of CSS CdTe films. Total area conversion efficiency of 14.6%, verified by the National Renewable Energy Laboratory, has been achieved for solar cells of about 1 cm2 area. Solar cell prepared by using ZnO, ZnSe, or Cd1-xZnxS as window have significantly lower photovoltage than CdS/CdTe solar cells.

  9. Selective and low temperature transition metal intercalation in layered tellurides

    Science.gov (United States)

    Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi

    2016-12-01

    Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid.

  10. Thin tungsten telluride layer preparation by thermal annealing

    Science.gov (United States)

    Lu, Wei; Zhang, Yudao; Zhu, Zusong; Lai, Jiawei; Zhao, Chuan; Liu, Xuefeng; Liu, Jing; Sun, Dong

    2016-10-01

    We report a simple method to prepare a thin Tungsten Telluride (WTe2) flake with accurate thickness control, which allows preparing and studying this two dimensional material conveniently. First, the WTe2 flake, which is relatively thick due to its strong interlayer van der Waals forces, is obtained by a conventional mechanical exfoliation method. Then, the exfoliated flake is annealed at 600 °C under a constant Ar protecting flow. Raman and atomic force spectroscopy characterizations demonstrate that thermal annealing can effectively thin down the WTe2 flake and retain its original lattice structure, though its surface smoothness is slightly deteriorated. Additionally, systematical study indicates that the thinning process strongly depends on the initial thickness of the WTe2 flake before annealing: the thinning rate increases from 0.12 nm min-1 to 0.36 nm min-1 as the initial thickness increases from 10 nm to 45 nm, while the roughness of the final product also increases with the increase of its initial thickness. However, the method fails when it is applied to WTe2 flakes thicker than 100 nm, resulting in uneven or burnt surface, which is possibly caused by big cavities formed by a large amount of defects gathered at the top surface.

  11. Optical Properties of Bismuth Tellurite Based Glass

    Directory of Open Access Journals (Sweden)

    Hooi Ming Oo

    2012-04-01

    Full Text Available A series of binary tellurite based glasses (Bi2O3x (TeO2100−x was prepared by melt quenching method. The density, molar volume and refractive index increase when bismuth ions Bi3+ increase, this is due to the increased polarization of the ions Bi3+ and the enhanced formation of non-bridging oxygen (NBO. The Fourier transform infrared spectroscopy (FTIR results show the bonding of the glass sample and the optical band gap, Eopt decreases while the refractive index increases when the ion Bi3+ content increases.

  12. Optical properties of bismuth tellurite based glass.

    Science.gov (United States)

    Oo, Hooi Ming; Mohamed-Kamari, Halimah; Wan-Yusoff, Wan Mohd Daud

    2012-01-01

    A series of binary tellurite based glasses (Bi(2)O(3))(x) (TeO(2))(100-) (x) was prepared by melt quenching method. The density, molar volume and refractive index increase when bismuth ions Bi(3+) increase, this is due to the increased polarization of the ions Bi(3+) and the enhanced formation of non-bridging oxygen (NBO). The Fourier transform infrared spectroscopy (FTIR) results show the bonding of the glass sample and the optical band gap, E(opt) decreases while the refractive index increases when the ion Bi(3+) content increases.

  13. Determining the background levels of bismuth in tissues of wild game birds: a first step in addressing the environmental consequences of using bismuth shotshells.

    Science.gov (United States)

    Jayasinghe, R; Tsuji, L J S; Gough, W A; Karagatzides, J D; Perera, D; Nieboer, E

    2004-11-01

    Bismuth shotshells have been approved as a "nontoxic" alternative to lead in North America. Approval was based on a limited number of studies; even background levels of bismuth in wildfowl were unknown. We report on the concentration of bismuth (and lead) in muscle and liver tissues of wildfowl (Anas platyrhynchos, Anas acuta, Anas crecca, Branta canadensis, Chen caerulescens) harvested with lead shotshell. Average liver-bismuth levels detected in the present study (e.g., teal, 0.05 microg/g dw; mallard, 0.09 microg/g dw) suggest analytical error in other studies examining the effects of bismuth in birds. Significant positive relationships between bismuth- and lead-tissue levels for muscle when all species were combined (and for B. canadensis and C. caerulescens separately) can be explained by noting that bismuth is a contaminant of lead. Thus, more research is recommended to confirm the appropriateness of bismuth as a "nontoxic" shot alternative.

  14. Effect of Indium on the Superconducting Transition Temperature of Tin Telluride

    Science.gov (United States)

    Zhong, Ruidan; Schneeloch, John; Shi, Xiaoya; Li, Qiang; Tranquada, John; Gu, Genda

    2013-03-01

    Indium-doped tin telluride is one of the most appealing topological superconductors. We have grown a series of Sn1-xInxTe crystals with different indium concentrations (0.1 <=x <=1.0). The results show indium doping improves the superconducting transition temperature significantly and is highly related to the indium concentration. The maximum Tc of indium-doped tin telluride polycrystalline is 4.5K for x =0.4. Single crystals of Sn1-xInxTe were also grown by the floating zone method, and their magnetic properties were characterized.

  15. Directional Solidification of Mercury Cadmium Telluride in Microgravity

    Science.gov (United States)

    Lechoczhy, Sandor L.; Gillies, Donald C.; Szofran, Frank R.; Watring, Dale A.

    1998-01-01

    Mercury cadmium telluride (MCT) has been directionally solidified for ten days in the Advanced Automated Directional Solidification Furnace (AADSF) on the second United States Microgravity Payload Mission (USMP-2). A second growth experiment is planned for the USMP-4 mission in November 1997. Results from USMP-2 demonstrated significant changes between microgravity and ground-based experiments, particularly in the compositional homogeneity. Changes were also observed during the microgravity mission which were dependent on the attitude of the space shuttle and the relative magnitudes of axial and transverse residual accelerations with respect to the growth axis of the crystal. Issues of shuttle operation, especially those concerned with safety and navigation, and the science needs of other payloads dictated the need for changes in attitude. One consequence for solidification of MCT in the USMP4 mission is the desire for a shorter growth time to complete the experiment without subjecting the sample to shuttle maneuvers. By using a seeded technique and a pre-processed boule of MCT with an established diffusion layer quenched into the solid, equilibrium steady state growth can be established within 24 hours, rather than the three days needed in USMP-2. The growth of MCT in AADSF during the USMP-4 mission has been planned to take less than 72 hours with 48 hours of actual growth time. A review of the USMP-2 results will be presented, and the rationale for the USMP-4 explained. Pre-mission ground based tests for the USN4P-4 mission will be presented, as will any available preliminary flight results from the mission.

  16. Telluride films and waveguides for IR integrated optics

    Energy Technology Data Exchange (ETDEWEB)

    Barthelemy, Eleonore; Vigreux, Caroline; Pradel, Annie [Institut Charles Gerhardt Montpellier, UMR CNRS 5253, Universite Montpellier II, CC1503, 34095 Montpellier Cedex 5 (France); Parent, Gilles [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, Universite de Nancy-Lorraine, BP239, 54506 Vandoeuvre Les Nancy Cedex (France); Barillot, Marc [Thales Alenia Space, 100 Bld. du midi, BP99, 06156 Cannes La Bocca Cedex (France)

    2011-09-15

    The fabrication of micro-components for far infrared applications such as spatial interferometry requires the realization of single-mode channel waveguides being able to work in the infrared region. One of the key issues in case of channel waveguides is the selection of materials for the core layer. Amorphous telluride films are particularly attractive for their transparency in a large spectral domain in the infrared region. A second key issue is the selection of an appropriate method for film deposition. Indeed, waveguides for far infrared applications are characterized by a thick core layer (10-15 {mu}m, typically). The challenge is thus to select a deposition method which ensures the deposition of thick films of optical quality. In this paper, it is shown that thermal co-evaporation meets this challenge. In particular, it allows varying the composition of the films very easily and thus adjusting their optical properties (refractive index, optical band gap). The example of thermally co-evaporated Te-Ge films is given. Films with typical thickness of 7-15 {mu}m were elaborated. Their morphological, structural, thermal and optical properties were measured. A particular attention was paid to the checking of the film homogeneity. The realized waveguiding structures and their optical testing are then described. In particular, the first transmission measurements at 10.6 {mu}m are presented. In conclusion, the feasibility of micro-components based on the stacking and etching of chalcogenide films is demonstrated, opening the door to applications related to detection in the mid- and thermal infrared spectral domains (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Current transport mechanisms in mercury cadmium telluride diode

    Science.gov (United States)

    Gopal, Vishnu; Li, Qing; He, Jiale; He, Kai; Lin, Chun; Hu, Weida

    2016-08-01

    This paper reports the results of modelling of the current-voltage characteristics (I-V) of a planar mid-wave Mercury Cadmium Telluride photodiode in a gate controlled diode experiment. It is reported that the diode exhibits nearly ideal I-V characteristics under the optimum surface potential leading to the minimal surface leakage current. Deviations from the optimum surface potential lead to non ideal I-V characteristics, indicating a strong relationship between the ideality factor of the diode with its surface leakage current. Diode's I-V characteristics have been modelled over a range of gate voltages from -9 V to -2 V. This range of gate voltages includes accumulation, flat band, and depletion and inversion conditions below the gate structure of the diode. It is shown that the I-V characteristics of the diode can be very well described by (i) thermal diffusion current, (ii) ohmic shunt current, (iii) photo-current due to background illumination, and (iv) excess current that grows by the process of avalanche multiplication in the gate voltage range from -3 V to -5 V that corresponds to the optimum surface potential. Outside the optimum gate voltage range, the origin of the excess current of the diode is associated with its high surface leakage currents. It is reported that the ohmic shunt current model applies to small surface leakage currents. The higher surface leakage currents exhibit a nonlinear shunt behaviour. It is also shown that the observed zero-bias dynamic resistance of the diode over the entire gate voltage range is the sum of ohmic shunt resistance and estimated zero-bias dynamic resistance of the diode from its thermal saturation current.

  18. Inhibition of urease by bismuth(III): implications for the mechanism of action of bismuth drugs.

    Science.gov (United States)

    Zhang, Li; Mulrooney, Scott B; Leung, Andy F K; Zeng, Yibo; Ko, Ben B C; Hausinger, Robert P; Sun, Hongzhe

    2006-10-01

    Bismuth compounds are widely used for the treatment of peptic ulcers and Helicobacter pylori infections. It has been suggested that enzyme inhibition plays an important role in the antibacterial activity of bismuth towards this bacterium. Urease, an enzyme that converts urea into ammonia and carbonic acid, is crucial for colonization of the acidic environment of the stomach by H. pylori. Here, we show that three bismuth complexes exhibit distinct mechanisms of urease inhibition, with some differences dependent on the source of the enzyme. Bi(EDTA) and Bi(Cys)(3) are competitive inhibitors of jack bean urease with K(i) values of 1.74 +/- 0.14 and 1.84 +/- 0.15 mM, while the anti-ulcer drug, ranitidine bismuth citrate (RBC) is a non-competitive inhibitor with a K (i) value of 1.17 +/- 0.09 mM. A (13)C NMR study showed that Bi(Cys)(3) reacts with jack bean urease during a 30 min incubation, releasing free cysteines from the metal complex. Upon incubation with Bi(EDTA) and RBC, the number of accessible cysteine residues in the homohexameric plant enzyme decreased by 5.80 +/- 0.17 and 11.94 +/- 0.13, respectively, after 3 h of reaction with dithiobis(2-nitrobenzoic acid). Kinetic analysis showed that Bi(EDTA) is both a competitive inhibitor and a time-dependent inactivator of the recombinant Klebsiella aerogenes urease. The active C319A mutant of the bacterial enzyme displays a significantly reduced sensitivity toward inactivation by Bi(EDTA) compared with the wild-type enzyme, consistent with binding of Bi(3+) to the active site cysteine (Cys(319)) as the mechanism of enzyme inactivation.

  19. Hierarchical bismuth phosphate microspheres with high photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Lizhai; Wei, Tian; Lin, Nan; Yu, Haiyun [Anhui University of Technology, Ma' anshan (China). Key Laboratory of Materials Science and Processing of Anhui Province

    2016-05-15

    Hierarchical bismuth phosphate microspheres have been prepared by a simple hydrothermal process with polyvinyl pyrrolidone. Scanning electron microscopy observations show that the hierarchical bismuth phosphate microspheres consist of nanosheets with a thickness of about 30 nm. The diameter of the microspheres is about 1 - 3 μm. X-ray diffraction analysis shows that the microspheres are comprised of triclinic Bi{sub 23}P{sub 4}O{sub 44.5} phase. The formation of the hierarchical microspheres depends on polyvinyl pyrrolidone concentration, hydrothermal temperature and reaction time. Gentian violet acts as the pollutant model for investigating the photocatalytic activity of the hierarchical bismuth phosphate microspheres under ultraviolet-visible light irradiation. Irradiation time, dosage of the hierarchical microspheres and initial gentian violet concentration on the photocatalytic efficiency are also discussed. The hierarchical bismuth phosphate microspheres show good photocatalytic performance for gentian violet removal in aqueous solution.

  20. Diffused phase transition in fine-grained bismuth vanadate ceramics

    OpenAIRE

    Shantha, K; Varma, KBR

    1999-01-01

    Nanocrystalline powders of ferroelectric bismuth vanadate, Bi4V2O11 (n-BiV), with crystallite size less than 50 nm, were obtained by mechanical milling of a stoichiometric mixture of bismuth oxide and vanadium pentoxide. The n-BiV powders on sintering yielded high-density, fine-grained ceramics with improved dielectric and polar characteristics. Dielectric studies on samples obtained from milled powders indicated that the ferroelectric-to-paraelectric phase transition temperature is strongly ...

  1. Melting and solidification of bismuth inclusions in aluminium

    DEFF Research Database (Denmark)

    Thoft, N.B.; Bohr, J.; Buras, B.

    1995-01-01

    Supercooling of crystalline bismuth inclusions in aluminium crystals has been observed and studied with different techniques: x-ray diffraction, in situ Rutherford backscattering/channelling spectrometry and transmission electron microscopy. The results of the measurements with different experime......Supercooling of crystalline bismuth inclusions in aluminium crystals has been observed and studied with different techniques: x-ray diffraction, in situ Rutherford backscattering/channelling spectrometry and transmission electron microscopy. The results of the measurements with different...

  2. Studies on bismuth carboxylates—synthesis and characterization of a new structural form of bismuth(III) dipicolinate

    Indian Academy of Sciences (India)

    O Anjaneyulu; K C Kumara Swamy

    2011-03-01

    Synthesis and X-ray structure of a new bismuth dipicolinate cooordination polymer, {[Bi((2,6-O2C)2C5H3N)((2-HO2C-6-O2C)C5H3N)(H2O)]2.5H2O} (7) are presented. Compound 7 has dimeric units with a Bi2O2 skeleton that are linked by additional weak Bi-O interactions leading to a polymeric structure. The overall coordination number at bismuth is 9 [two Bi-N and seven Bi-O bonds]. New routes to a second crystalline modification (4′) of the previously reported coordination polymer, bismuth tris(picolinate), [Bi(2-O2C-C5H4N)3] (4), are described; bond parameters in the two crystalline forms (4 and 4′) are compared. In both the compounds 4′ and 7, bismuth has a distorted tricapped trigonal prismatic geometry.

  3. In situ electron beam irradiated rapid growth of bismuth nanoparticles in bismuth-based glass dielectrics at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shiv Prakash; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in [Central Glass and Ceramic Research Institute (CSIR, India), Glass Science and Technology Section, Glass Division (India)

    2011-09-15

    In this study, in situ control growth of bismuth nanoparticles (Bi{sup 0} NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction and high-resolution transmission electron microscopy. The EB irradiation for 2-8 min enhanced the construction of bismuth nanoparticles with a rhombohedral structure and diameter of 4-9 nm. The average particle size was found to increase with the irradiation time. Bismuth metal has a melting point of 271 Degree-Sign C and this low melting temperature makes easy the progress of energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for integrated optics and other applications.

  4. China Plays an Important Role in the World Bismuth Market Place

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>Available statistics shows that China not only has the world largest bismuth deposit but also is the world largest producer, exporter and consumer country. Particularly in the recent three years, China’s production and supply as well as the related policy changes has become a major factor in the bismuth market price fluctuations. China’s bismuth ore production in the recent two years has been kept stable and China’s output of bismuth ore concentrates accounts for

  5. Prognostic Value of Bismuth Typing and Modified T-stage in Hilar Cholangiocarcinoma

    Directory of Open Access Journals (Sweden)

    Shengen Yi

    2015-01-01

    Conclusion: The majority of our patients with HCC were characterized as Subtype IV in Bismuth typing and Stage T3 in modified T-stage. Both Bismuth typing and modified T-stage showed prognostic value in HCC. Compared with Bismuth typing, modified T-stage is a better indicator of the resectability of HCC.

  6. Bismuth X-ray absorber studies for TES microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Sadleir, J.E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States) and University of Illinois Physics Department, Urbana, IL 61801 (United States)]. E-mail: sadleir@milkyway.gsfc.nasa.gov; Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brekosky, R.P. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chervenak, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkbeiner, F. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R.L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); King, J.M. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Porter, F.S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Robinson, I.K. [University of Illinois Physics Department, Urbana, IL 61801 (United States); Saab, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Talley, D.J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2006-04-15

    Bismuth's large atomic number and low carrier density makes it an attractive X-ray absorber material for microcalorimeters. Bismuth's long Fermi wavelength and long mean free paths have motivated much interest in the fabrication of high quality bismuth films to study quantum size effects. Despite such incentives, fabrication of high quality bismuth films has proven difficult, and measured properties of such films are highly variable in the literature. Implementing a bismuth deposition process for TES (superconducting Transition Edge Sensor) device fabrication presents additional challenges particularly at interfaces due to the inherent granularity and surface roughness of its films, its low melting point, and its tendency to diffuse and form undesired intermetallic phases. We report observations of Bi-Cu and Bi-Au diffusion in our devices correlating with large shifts in T{sub c} (superconducting transition temperature). Using SEM and in situ R vs T annealing experiments we have been able to study these diffusion processes and identify their activation temperatures.

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

    Science.gov (United States)

    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.

  8. Bismuth nanoparticles for phenolic compounds biosensing application.

    Science.gov (United States)

    Mayorga-Martinez, Carmen C; Cadevall, Miquel; Guix, Maria; Ros, Josep; Merkoçi, Arben

    2013-02-15

    The rapid determination of trace phenolic compounds is of great importance for evaluating the total toxicity of contaminated water samples. Nowadays, electrochemical tyrosinase (Tyr) based biosensors constitute a promising technology for the in situ monitoring of phenolic compounds because of their advantages such as high selectivity, low production cost, promising response speed, potential for miniaturization, simple instrumentation and easy automatization. A mediator-free amperometric biosensor for phenolic compounds detection based on the combination of bismuth nanoparticles (BiNPs) and Tyr for phenol detections will be hereby reported. This is achieved through the integration of BiNPs/Tyr onto the working electrode of a screen printed electrode (SPE) by using glutaraldehyde as a cross-linking agent. BiNPs/Tyr biosensor is evaluated by amperometric measurements at -200 mV DC and a linear range of up to 71 μM and 100 μM and a correlation coefficient of 0.995 and 0.996 for phenol and catechol, respectively. The very low DC working potential ensures the avoidance of interferences making this biosensor an advantageous device for real sample applications. In addition, the response mechanism including the effect of BiNPs based on electrochemical studies and optical characterizations will be also discussed. The obtained results may open the way to many other BiNPs applications in the biosensing field.

  9. Laser Spectroscopy of Neutron Rich Bismuth Isotopes

    CERN Multimedia

    2002-01-01

    %IS344 :\\\\ \\\\ The aim of the experiment is to measure the optical isotope shifts and hyperfine structures of bismuth isotopes across the N=126 shell closure in order to extract the change in mean square charge radii ($\\delta\\langle r^{2}\\rangle$) and static moments. These include the first isotones of lead to be measured directly above the shell closure and will provide new information on the systematics of the kink ($\\delta\\langle r^{2}\\rangle)$ seen in the lead isotopic chain. After two very successful runs the programme has been extended to include the neutron deficient isotopes below $^{201}$Bi to study the systematics across the $i_{13/2}$ neutron sub-shell closure at N=118.\\\\ \\\\ During the initial 2 runs (9 shifts) the isotope shifts and hyperfine structures of three new isotopes, $ ^{210,212,213}$Bi and the 9$^{-}$ isomer of $^{210}$Bi have been measured. The accuracy of the previous measurements of $^{205,206,208}$Bi have been greatly improved. The samples of $ ^{208,210,210^{m}}$Bi were prepared by c...

  10. LMO dielectronic resonances in highly charged bismuth

    Science.gov (United States)

    Smiga, Joseph; Gillaspy, John; Podpaly, Yuri; Ralchenko, Yuri

    2016-05-01

    Dielectronic resonances from high-Z elements are important for the analysis of high temperature plasmas. Thus, the extreme ultraviolet spectra of highly charged bismuth were measured using the NIST electron beam ion trap (EBIT) at beam energies ranging from 8.7 keV to 9.2 keV. The measured intensity ratios between forbidden magnetic-dipole lines in Bi64+ and Bi63+ show strong resonance features. The experimental data were compared to theoretical predictions from a large-scale collisional-radiative model with the code NOMAD, and good agreement was found that allowed the identification of observed resonance features as the LMO inner-shell dielectronic resonances. It is common practice in EBIT experiments that ions are periodically dumped from the trap and replaced. However, in this particular experiment, the contents of the trap were not dumped for the duration of each 10 minute sampling. The effects of trap stability were studied and a small but noticeable shift in beam energy over time was observed. Potential explanations for this are considered.

  11. Bismuth iron oxide thin films using atomic layer deposition of alternating bismuth oxide and iron oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Puttaswamy, Manjunath; Vehkamäki, Marko [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); University of Tartu, Institute of Physics, W. Ostwald 1, EE-50411 Tartu (Estonia); Dimri, Mukesh Chandra [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Kemell, Marianna; Hatanpää, Timo; Heikkilä, Mikko J. [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Mizohata, Kenichiro [University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 Helsinki (Finland); Stern, Raivo [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Ritala, Mikko; Leskelä, Markku [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland)

    2016-07-29

    Bismuth iron oxide films with varying contributions from Fe{sub 2}O{sub 3} or Bi{sub 2}O{sub 3} were prepared using atomic layer deposition. Bismuth (III) 2,3-dimethyl-2-butoxide, was used as the bismuth source, iron(III) tert-butoxide as the iron source and water vapor as the oxygen source. The films were deposited as stacks of alternate Bi{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} layers. Films grown at 140 °C to the thickness of 200–220 nm were amorphous, but crystallized upon post-deposition annealing at 500 °C in nitrogen. Annealing of films with intermittent bismuth and iron oxide layers grown to different thicknesses influenced their surface morphology, crystal structure, composition, electrical and magnetic properties. Implications of multiferroic performance were recognized in the films with the remanent charge polarization varying from 1 to 5 μC/cm{sup 2} and magnetic coercivity varying from a few up to 8000 A/m. - Highlights: • Bismuth iron oxide thin films were grown by atomic layer deposition at 140 °C. • The major phase formed in the films upon annealing at 500 °C was BiFeO{sub 3}. • BiFeO{sub 3} films and films containing excess Bi favored electrical charge polarization. • Slight excess of iron oxide enhanced saturative magnetization behavior.

  12. Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor

    Indian Academy of Sciences (India)

    Sandeep Arya; Saleem Khan; Suresh Kumar; Rajnikant Verma; Parveen Lehana

    2013-08-01

    Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic solution of copper (II) sulphate (CuSO4.5H2O) and tellurium oxide (TeO2) on a copper substrate by template-assisted electrodeposition method. The electrodeposition was conducted at 30 °C and the length of nanowires was controlled by adjusting deposition time. Structural characteristics were examined using X-ray diffraction and scanning electron microscope which confirm the formation of CuTe nanowires. Investigation for chemical sensing was carried out using air and chloroform, acetone, ethanol, glycerol, distilled water as liquids having dielectric constants 1, 4.81, 8.93, 21, 24.55, 42.5 and 80.1, respectively. The results unequivocally prove that copper telluride nanowires can be fabricated as chemical sensors with enhanced sensitivity and reliability.

  13. Characterization of large cadmium zinc telluride crystals grown by traveling heater method

    DEFF Research Database (Denmark)

    Chen, H.; Awadalla, S.A.; Iniewski, K.

    2008-01-01

    The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions/precipitates of these c......The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions...

  14. Kelvin probe studies of cesium telluride photocathode for the AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez, D.; Wisniewski, E. E.; Yusof, Z.; Harkay, K.; Spentzouris, L.; Terry, J. [Physics Department at Illinois Institute of Technology, Chicago, IL 60616 and High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Accelerator Science Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Physics Department at Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2012-12-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (> 1%), is robust in a photoinjector, and long lifetime. This photocathode is fabricated in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch ({approx}50 nC) in a long bunch train. We present some results from a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV light exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  15. Optical property of amorphous semiconductor mercury cadmium telluride from first-principles study

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The structural and optical properties of amorphous semiconductor mercury cadmium telluride (a-MCT) are obtained by the first principles calculations. The total pair distribution functions and the density of states show that the a-MCT has the semiconductor characteristic. The calculated results of dielectric function show that E2 peak of the imaginary of dielectric function for the crystal mercury cadmium telluride abruptly disappears in the amorphous case due to the long-range disorders. And the imaginary of dielectric function of a-MCT shows a large broad peak, which is in agreement with the available results of other amorphous semiconductors. From the linear extrapolation of the curve ωε 2(ω)1/2 versus ω, it can be obtained that the optical energy gap of amorphous semiconductor Hg0.5Cd0.5Te is 0.51±0.05 eV.

  16. Synthesis of lead telluride particles by thermal decomposition method for thermoelectric applications

    Energy Technology Data Exchange (ETDEWEB)

    Leontyev, V.G.; Ivanova, L.D. [Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Leninskii prospect, 49, 119991 Moscow (Russian Federation); Bente, K.; Lazenka, V.V. [Institut fuer Mineralogie, Kristallographie und Materialwissenschaft, Leipzig University, Scharnhorst str. 20, 04275 Leipzig (Germany); Gremenok, V.F. [Scientific-Practical Materials Research Centre of the NAS of Belarus, P. Brovka str. 19, 220072 Minsk (Belarus)

    2012-06-15

    The lead telluride fine crystalline particles were synthesized using thermal decomposition and chemical interaction of lead acetate and tellurium powder mixture in reducing atmosphere (H{sub 2}). For the process control, thermal gravimetry (TG), the different-scanning calorimetry (DSC), X-ray diffraction (XRD), electronic microscopy (SEM) and measurements of the specific surface of particles were used. Additionally the influence of gas phases on the decomposition kinetics, crystal structure, size, specific surface of the particles and the physical properties were analyzed. Seebeck coefficient values increased with decreasing synthesis temperature and increasing specific surfaces of the powder. The presented method of preparing lead telluride polydisperse particles is developed to create nano-structured thermoelectric materials with high figure of merit. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. GEOLOGY OF THE FLORENCIA GOLD – TELLURIDE DEPOSIT (CAMAGÜEY, CUBA AND SOME METALLURGICAL CONSIDERATIONS

    Directory of Open Access Journals (Sweden)

    López K Jesús M.

    2006-12-01

    Full Text Available This paper describes the results from a study of the Florencia gold-telluride deposit in Central Cuba, including mineralogical, petrographical, microprobe and chemical analysis. Valuable information is provided for the exploration, mining and processing of gold ores from other nearby deposits with similar characteristics. Results highlight changes in the mineralogical composition of the ores between the north and south sectors of the deposit, as reflected in metallurgical concentrates after beneficiation and flotation of samples from these sectors.
    It is shown that gold deposits of the Cretaceous Volcanic Arc of Cuba largely consist of native gold, telluride and pyrite, where arsenopyrite is almost absent. Traces of lead, zinc and cadmium are present in the periphery of the main ore zones.

  18. Epitaxial growth of cadmium telluride films on silicon with a buffer silicon carbide layer

    Science.gov (United States)

    Antipov, V. V.; Kukushkin, S. A.; Osipov, A. V.

    2017-02-01

    An epitaxial 1-3-μm-thick cadmium telluride film has been grown on silicon with a buffer silicon carbide layer using the method of open thermal evaporation and condensation in vacuum for the first time. The optimum substrate temperature was 500°C at an evaporator temperature of 580°C, and the growth time was 4 s. In order to provide more qualitative growth of cadmium telluride, a high-quality 100-nm-thick buffer silicon carbide layer was previously synthesized on the silicon surface using the method of topochemical substitution of atoms. The ellipsometric, Raman, X-ray diffraction, and electron-diffraction analyses showed a high structural perfection of the CdTe layer in the absence of a polycrystalline phase.

  19. Characterization of bismuth nanospheres deposited by plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: cscientific2@aec.org.sy [IBA Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Al-Hawat, Sh.; Akel, M. [Physics Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Mrad, O. [Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, A. Reyes [Facultad de Ciencias, Universidad Autónoma del Estado de México, Carretera Toluca, Ixtlahuaca Kilómetro 15.5, C.P. 50200 Edo. de México (Mexico); Hautefeuille, M., E-mail: mathieu_h@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Circuito Exterior S/N, Coyoacán, Ciudad Universitaria, C.P. 04510 D.F. Mexico (Mexico); García, A. Esparza [Fotofísica y Películas Delgadas, Departamento de Tecnociencias, CCADET-UNAM, Circuito exterior s/n C.P. 04510 Cd. Universitaria, D.F. Mexico (Mexico); Mejia, O. Olea [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, Km 14.5, Unidad El Rosedal, 50200 San Cayetano, Estado de México (Mexico); López, M.A. Camacho [Facultad de Química, Universidad Autónoma del Estado de México, Tollocan s/n, esq. Paseo Colón, Toluca, Estado de México 50110 (Mexico)

    2015-05-01

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: 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.

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

    Science.gov (United States)

    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.

  2. Aqueous-solution route to zinc telluride films for application to CO₂ reduction.

    Science.gov (United States)

    Jang, Ji-Wook; Cho, Seungho; Magesh, Ganesan; Jang, Youn Jeong; Kim, Jae Young; Kim, Won Yong; Seo, Jeong Kon; Kim, Sungjee; Lee, Kun-Hong; Lee, Jae Sung

    2014-06-01

    As a photocathode for CO2 reduction, zinc-blende zinc telluride (ZnTe) was directly formed on a Zn/ZnO nanowire substrate by a simple dissolution-recrystallization mechanism without any surfactant. With the most negative conduction-band edge among p-type semiconductors, this new photocatalyst showed efficient and stable CO formation in photoelectrochemical CO2 reduction at -0.2--0.7 V versus RHE without a sacrificial reagent.

  3. The heat capacity of solid antimony telluride Sb2Te3

    Science.gov (United States)

    Pashinkin, A. S.; Malkova, A. S.; Mikhailova, M. S.

    2008-05-01

    The literature data on the heat capacity of solid antimony telluride over the range 53 895 K were analyzed. The heat capacity of Sb2Te3 was measured over the range 350 700 K on a DSM-2M calorimeter. The equation for the temperature dependence was suggested. The thermodynamic functions of Sb2Te3 were calculated over the range 298.15 700 K.

  4. Compact and Integrated Liquid Bismuth Propellant Feed System

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, A., E-mail: soumen.basu@phy.nitdgp.ac.in; Banerjee, M., E-mail: soumen.basu@phy.nitdgp.ac.in; Basu, S., E-mail: soumen.basu@phy.nitdgp.ac.in [Department of Physics, National Institute of Technology, Durgapur-713209 (India); Pal, M. [CSIR-Central Mechanical Engineering Research Institute, Durgapur-713209 (India)

    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. Microscopic and voltammetric properties of lustrous bismuth deposits

    OpenAIRE

    Krolicka, Agnieszka; Bobrowski, Andrzej; Pamuła, Elżbieta

    2010-01-01

    A comparison of lustrous bismuth films, plated at glassy carbon, platinum and gold supports, is presented. The voltammetric performance of preplated bismuth film electrodes was tested using 50 μg/L In(III) and 50 μg/L Pb(II) solutions in 0.1 M acetic buffer in square wave and differential pulse modes. The influence of support material, plating solution concentration and storing conditions on the voltammetric response of BiFEs is discussed. The results of microscopic examination...

  7. The effect of different annealing temperatures on tin and cadmium telluride phases obtained by a modified chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Anderson Fuzer [Departamento de Química, CCE, Universidade Federal do Espírito Santo, Campus Goiabeiras, 29075-910 Vitória, Espírito Santo (Brazil); Porto, Arilza de Oliveira, E-mail: arilzaporto@yahoo.com.br [Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Magela de Lima, Geraldo [Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Paniago, Roberto [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Ardisson, José Domingos [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN/CNEN, Belo Horizonte, Minas Gerais (Brazil)

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► Synthesis of cadmium and tin telluride. ► Chemical route to obtain pure crystalline cadmium and tin telluride. ► Effect of the annealing temperature on the crystalline phases. ► Removal of tin oxide as side product through thermal treatment. -- Abstract: In this work tin and cadmium telluride were prepared by a modification of a chemical route reported in the literature to obtain metallacycles formed by oxidative addition of tin-tellurium bonds to platinum (II). Through this procedure it was possible to obtain tin and cadmium telluride. X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the crystalline phases obtained as well as the presence of side products. In the case of tin telluride it was identified potassium chloride, metallic tellurium and tin oxide as contaminants. The tin oxidation states were also monitored by {sup 119}Sn Mössbauer spectroscopy. The annealing in hydrogen atmosphere was chosen as a strategy to reduce the tin oxide and promote its reaction with the excess of tellurium present in the medium. The evolution of this tin oxide phase was studied through the annealing of the sample at different temperatures. Cadmium telluride was obtained with high degree of purity (98.5% relative weight fraction) according to the Rietveld refinement of X-ray diffraction data. The modified procedure showed to be very effective to obtain amorphous tin and cadmium telluride and the annealing at 450 °C has proven to be useful to reduce the amount of oxide produced as side product.

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

    Science.gov (United States)

    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.

  9. Bismuth centred magnetic perovskite: A projected multiferroic

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Asish K., E-mail: asish.k@gmail.com [Discipline of Physics, Indian Institute of Information Technology, Design and Manufacturing, Dumna Airport Road, Jabalpur 482005 (India); Seikh, Md. Motin [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal 731235 (India); Nautiyal, Pranjal [Discipline of Mechanical Engineering, Indian Institute of Information Technology, Design and Manufacturing, Dumna Airport Road, Jabalpur 482005 (India)

    2015-03-15

    In recent time substantial attention has been initiated to understand the physics behind multiferroism and to design new multiferroic materials. BiMnO{sub 3} and BiFeO{sub 3} are the well-studied Bi-centred multiferroic oxides. BiMnO{sub 3} is a ferromagnetic–ferroelectric (metastable) phase and require drastic conditions to synthesize. However, lanthanum substituted BiMnO{sub 3} phases stabilized at ambient pressure. It is thus of major importance to increase the number of ferromagnetic perovskites with Bi cations that could be designed under ambient conditions. In this article, we have presented an up to date report of investigations on Bi-centred magnetic perovskites, a prospective material for multiferroic application. Central focus is concentrated on La{sub 0.5}Bi{sub 0.5}MnO{sub 3} perovskite with various substitutions at different levels. A few of these perovskites are found to be of practical importance e.g. La{sub 0.5}Bi{sub 0.5}Mn{sub 0.67}Co{sub 0.33}O{sub 3} with high dielectric permittivity coupled with ferromagnetism. A comprehensive analysis of different physical functionalities and their interrelation for a wide range of compositions of these Bi-centred perovskites is presented. It has been found that the complex magnetic behaviour originates from mixed valence metal ions. The ferroelectricity is associated with the 6s{sup 2} lone pair of Bi{sup 3+} cations. The magnetic ground state influences the dielectric properties reflecting the multiferroism in a single material. - Highlights: • Multiferroics have attracted increasing attention due to their possible device applications. • Bismuth centred magnetic perovskite is one kind of such promising multiferroic materials. • Ferromagnetic Bi-perovskites, which are synthesized at ambient conditions, have been discussed.

  10. Ultrafast electronic dynamics in laser-excited crystalline bismuth

    Directory of Open Access Journals (Sweden)

    Chekalin S.

    2013-03-01

    Full Text Available Femtosecond spectroscopy was applied to capture complex dynamics of non equilibrium electrons in bismuth. Data analysis reveals significant wavevector dependence of electron-hole and electron-phonon coupling strength along the Γ-T direction of the Brillouin zone

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

    Science.gov (United States)

    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.

  12. Polymeric architectures of bismuth citrate based on dimeric building blocks

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Four bismuth complexes, (H2En)[Bi2(cit)2(H2O)4/3]·(H2O)x (1), (H2En)3[Bi2(cit)2Cl4]·(H2O)x (2), (HPy)2[Bi2(cit)2(H2O)8/5]·(H2O)x (3) and (H2En)[Bi2(cit)2](H2O)x (4) [cit = citrate4-; En = ethylenediamine; Py = pyridine] have been synthesized and crystallized. The crystal structures reveal that the basic building blocks in all of these complexes are bismuth citrate dimeric units which combine to form polymeric architectures. The embedded protonated ethylenediamine and pyridine moieties in the polymeric frameworks have been identified by X-ray crystallography and solid-state cross polarization/magic angle spinning (CP/MAS) 13C NMR. Based on the framework of complex 1, a structural model of a clinically used antiulcer drug, ranitidine bismuth citrate (RBC) was generated. The behavior of the protonated amine-bismuth citrate complexes in acidic aqueous solution has been studied by electrospray ionization-mass spectrometry (ESI-MS).

  13. Highly monodisperse bismuth nanoparticles and their three-dimensional superlattices.

    Science.gov (United States)

    Yarema, Maksym; Kovalenko, Maksym V; Hesser, Günter; Talapin, Dmitri V; Heiss, Wolfgang

    2010-11-01

    A simple and reproducible synthesis of highly monodisperse and ligand-protected bismuth nanoparticles (Bi NPs) is reported. The size of the single-crystalline and spherically shaped NPs is controlled between 11 and 22 nm mainly by the reaction temperature. The high uniformity of the NPs allows their self-assembly into long-range-ordered two- and three-dimensional superstructures.

  14. Oxygen semi-permeability of erbia-stabilized bismuth oxide

    NARCIS (Netherlands)

    Bouwmeester, H.J.M.; Kruidhof, H.; Burggraaf, A.J.; Gellings, P.J.

    1992-01-01

    The isothermal permeability of oxygen through sintered dense disks of bismuth oxide stabilized with 25 mol% erbia (BE25) has been studied at 610–810°C and oxygen pressures of 0.0001–1 atm. It is concluded that the permeating flux is rate limited both by solid state diffusion of electron holes and by

  15. Light-Induced Absorption in Nominally Pure Bismuth Silicon Oxide

    Institute of Scientific and Technical Information of China (English)

    李飞飞; 许京军; 孔勇发; 黄辉; 张光寅; 杨春晖; 徐玉恒

    2001-01-01

    Light-induced absorption in the nominally pure bismuth silicon oxide is investigated experimentally and the result shows that it consists of transient and persistent parts. The experimental evidence is analysed based on the model of three groups of trap (donor) centres.

  16. Bismuth-lead oxide, a new highly conductive oxygen materials

    NARCIS (Netherlands)

    Honnart, F.; Boivin, J.C.; Thomas, D.; Vries, de K.J.

    1983-01-01

    The transport properties of an oxygen-deficient solid solution containing lead and bismuth oxides have been investigated. The conductivity is larger than 1 (ω× cm)−1 at 600 °C. Thermogalvanic measurements confirm that no significant electronic contribution occurs in the range 1–10−3atm p O2. The hea

  17. High ionic conductivity in confined bismuth oxide-based heterostructures

    DEFF Research Database (Denmark)

    Sanna, Simone; Esposito, Vincenzo; Christensen, Mogens

    2016-01-01

    Bismuth trioxide in the cubic fluorite phase (δ-Bi2O3) exhibits the highest oxygen ionic conductivity. In this study, we were able to stabilize the pure -Bi2O3 at low temperature with no addition of stabilizer but only by engineering the interface, using highly coherent heterostructures made...

  18. Nanometer bismuth oxide produced by resistance heating vapor oxidation

    Institute of Scientific and Technical Information of China (English)

    HU Han-xiang; QIU Ke-qiang

    2006-01-01

    Bismuth oxide has wide applications in superconductive material, photoelectric material, electronic ceramic, electrolyte, and catalysts. To produce ultrafine bismuth oxide powders, some costly heating sources, such as plasma, high frequency induction, electron beam or laser, have to be used in the conventional vapor oxidation methods. The vapor oxidation method was improved by adding a reducing agent in the reaction system, where heating source was resistance tubular oven, instead of special heat source requirement. Nanometer bismuth oxide was prepared at 1 000-1 140 ℃, and the particle characteristics were investigated by XRD, SEM, DTA, laser sedimentograph. With low oxygen concentration (less than 20%) in the carrier gas, the bismuth oxide particle was near-sphere β-Bi2O3 with uniform and fine particle size (d0.5=65 nm, GSD=1.42); while with higher oxygen content (more than 50%), the powders were mixture of Bi2O2CO3 and β-Bi2O3.

  19. Ultrafast electron diffraction studies of optically excited thin bismuth films

    Energy Technology Data Exchange (ETDEWEB)

    Rajkovic, Ivan

    2008-10-21

    This thesis contains work on the design and the realization of an experimental setup capable of providing sub-picosecond electron pulses for ultrafast electron diffraction experiments, and performing the study of ultrafast dynamics in bismuth after optical excitation using this setup. (orig.)

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

    Science.gov (United States)

    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

  1. Bismuth tri-iodide radiation detector development

    Science.gov (United States)

    Gokhale, Sasmit S.

    Bismuth tri-iodide is an attractive material for room temperature radiation detection. BiI3 demonstrates a number of properties that are apt for semiconductor radiation detection, especially gamma ray spectroscopy. The high atomic number (ZBi = 83 and ZI = 53) and the relatively high density (5.78 g/cm3) cause the material to have good photon stopping power, while the large band-gap (1.67 eV ) allows it to function as a room temperature radiation detector without any cooling mechanism. This work presents the fabrication and characterization of BiI3 radiation detectors. For the purpose of this research detectors were fabricated by cutting BiI3 crystal boules, followed by mechanical and chemical surface treatments. Detectors with various electrode geometries enabling single polarity charge sensing were fabricated. The electrical characteristics and the radiation response of the detectors were measured. The radiation response measurement was performed at room temperature using a 241Am alpha particle source and a 241Am sealed gamma-ray source. The spectral resolutions of the detectors varied from 2.09% - 6.1% for 59.5 keV gamma-rays and between 26% - 40% for 5.48 MeV alpha particles. Charge carrier properties such as the electron and hole mobility and lifetime were also estimated. The electron mobility for an ultrapure BiI 3 detector was estimated to be approximately 433 cm 2/Vs while that for antimony doped BiI3 was estimated to be around 956 cm2/Vs and the mobility-lifetime product for electrons was estimated to be around 5.44 x 10-4 cm 2/V. Detector simulation was performed using the Monte Carlo simulation code MCNP5. A Matlab script which incorporates charge carrier trapping and statistical variation was written to generate a gamma-ray spectrum from the simulated energy deposition spectra. Measured and simulated spectra were compared to extract the charge carrier mobility-lifetime products, which for electrons and holes were estimated to be 5 x 10-3 cm2/V and 1.3 x

  2. Determining the background levels of bismuth in tissues of wild game birds: a first step in addressing the environmental consequences of using bismuth shotshells

    Energy Technology Data Exchange (ETDEWEB)

    Jayasinghe, R.; Tsuji, L.J.S.; Gough, W.A.; Karagatzides, J.D.; Perera, D.; Nieboer, E

    2004-11-01

    Bismuth shotshells have been approved as a 'nontoxic' alternative to lead in North America. Approval was based on a limited number of studies; even background levels of bismuth in wildfowl were unknown. We report on the concentration of bismuth (and lead) in muscle and liver tissues of wildfowl (Anas platyrhynchos, Anas acuta, Anas crecca, Branta canadensis, Chen caerulescens) harvested with lead shotshell. Average liver-bismuth levels detected in the present study (e.g., teal, 0.05 {mu}g/g dw; mallard, 0.09 {mu}g/g dw) suggest analytical error in other studies examining the effects of bismuth in birds. Significant positive relationships between bismuth- and lead-tissue levels for muscle when all species were combined (and for B. canadensis and C. caerulescens separately) can be explained by noting that bismuth is a contaminant of lead. Thus, more research is recommended to confirm the appropriateness of bismuth as a 'nontoxic' shot alternative.

  3. Operating Practice for Recovering Bismuth from Bismuth Dross%从铋渣中回收铋的生产实践

    Institute of Scientific and Technical Information of China (English)

    刘金铭

    2015-01-01

    阐述了从处理铅阳极泥时产生的铋渣中回收铋的生产实践,采用湿法浸出→氯氧铋→热浓碱转型→氧化铋→还原熔炼→火法精炼的生产工艺,为铋渣的处理提供了新的途径。%This paper expounds operating practice for recovering bismuth from bismuth dross that were outputed during dealing with the lead anode mud in pyrometallurgical process,which uesd production process of leaching—bismuth oxychloride—transformation—bismuth oxide—reduction smelting—pyrometallurgical refining.The operating practice provided a new technology to process the bismuth dross.

  4. Formation of Semimetallic Cobalt Telluride Nanotube Film via Anion Exchange Tellurization Strategy in Aqueous Solution for Electrocatalytic Applications.

    Science.gov (United States)

    Patil, Supriya A; Kim, Eun-Kyung; Shrestha, Nabeen K; Chang, Jinho; Lee, Joong Kee; Han, Sung-Hwan

    2015-11-25

    Metal telluride nanostructures have demonstrated several potential applications particularly in harvesting and storing green energy. Metal tellurides are synthesized by tellurization process performed basically at high temperature in reducing gas atmosphere, which makes the process expensive and complicated. The development of a facile and economical process for desirable metal telluride nanostructures without complicated manipulation is still a challenge. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and nonconducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature. The nanostructured films before and after ion exchange transformation reaction are characterized using field emission scanning electron microscope, energy dispersive X-ray analyzer, X-ray photoelectron spectroscopy, thin film X-ray diffraction technique, high resolution transmission electron microscope, and selected area electron diffraction analysis technique. After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3(-)/I(-) redox electrolyte based dye-sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3(-) with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a benchmarked Pt-film counter electrode. On the other hand, the telluride film electrode also demonstrates electrocatalytic activity for oxygen evolution reaction from oxidation of water.

  5. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Andreas

    2013-04-30

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while

  6. Spatial mapping of cadmium zinc telluride materials properties and electrical response to improve device yield and performance

    CERN Document Server

    Van Scyoc, J M; Yoon, H; Gilbert, T S; Hilton, N R; Lund, J C; James, R B

    1999-01-01

    Cadmium zinc telluride has experienced tremendous growth in its application to various radiation sensing problems over the last five years. However, there are still issues with yield, particularly of the large volume devices needed for imaging and sensitivity-critical applications. Inhomogeneities of various types and on various length scales currently prevent the fabrication of large devices of high spectral performance. This paper discusses the development of a set of characterization tools for quantifying these inhomogeneities, in order to develop improvement strategies to achieve the desired cadmium zinc telluride crystals for detector fabrication.

  7. Structure and Surface Analysis of SHI Irradiated Thin Films of Cadmium Telluride

    OpenAIRE

    Neelam Pahwa; A.D. Yadav; S.K. Dubey; A.P. Patel; Arvind Singh; D.C. Kothari

    2012-01-01

    Cadmium Telluride (CdTe) thin films grown by thermal evaporation on quartz substrates were irradiated with swift (100 MeV) Ni + 4 ions at various fluences in the range 1011 – 1013 cm – 2. The modification in structure and surface morphology has been analyzed as a function of fluence using XRD and AFM techniques. The XRD showed a reduction in peak intensity and grain size with increasing fluence. The AFM micrographs of irradiated thin films show small spherical nanostructures. In addition to d...

  8. High resolution X-ray diffraction imaging of lead tin telluride

    Science.gov (United States)

    Steiner, Bruce; Dobbyn, Ronald C.; Black, David; Burdette, Harold; Kuriyama, Masao; Spal, Richard; Simchick, Richard; Fripp, Archibald

    1991-01-01

    High resolution X-ray diffraction images of two directly comparable crystals of lead tin telluride, one Bridgman-grown on Space Shuttle STS 61A and the other terrestrially Bridgman-grown under similar conditions from identical material, present different subgrain structure. In the terrestrial, sample 1 the appearance of an elaborate array of subgrains is closely associated with the intrusion of regions that are out of diffraction in all of the various images. The formation of this elaborate subgrain structure is inhibited by growth in microgravity.

  9. Terahertz-field-induced second harmonic generation through Pockels effect in zinc telluride crystal.

    Science.gov (United States)

    Cornet, Marion; Degert, Jérôme; Abraham, Emmanuel; Freysz, Eric

    2014-10-15

    We report on the second harmonic generation (SHG) of a near-infrared pulse in a zinc telluride crystal through the Pockels effect induced by an intense terahertz pulse. The temporal and angular behaviors of the SHG have been measured and agree well with theoretical predictions. This phenomenon, so far overlooked, makes it possible to generate second harmonic through cascading of two second-order nonlinear phenomena in the near-infrared and terahertz ranges. We also show how this cascading process can be used to sample terahertz pulses.

  10. Operational Studies of Cadmium Zinc Telluride Microstrip Detectors using SVX ASIC Electronics

    Science.gov (United States)

    Krizmanic, John; Barbier, L. M.; Barthelmy, S.; Bartlett, L.; Birsa, F.; Gehrels, N.; Hanchak, C.; Kurczynski, P.; Odom, J.; Parsons, A.; Palmer, D.; Sheppard, D.; Snodgrass, S.; Stahle, C. M.; Teegarden, B.; Tueller, J.

    1997-04-01

    We have been investigating the operational properties of cadmium zinc telluride (CZT) microstrip detectors by using SVX ASIC readout electronics. This research is in conjunction with the development of a CZT-based, next generation gamma-ray telescope for use in the gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS) experiment. CZT microstrip detectors with 128 channels and 100 micron strip pitch have been fabricated and were interfaced to SVX electronics at Goddard Space Flight Center. Experimental results involving position sensing, spectroscopy, and CZT operational properties will be presented.

  11. Study of a high-resolution, 3-D positioning cadmium zinc telluride detector for PET

    OpenAIRE

    Gu, Y.; Matteson, J. L.; Skelton, R T; Deal, A C; Stephan, E A; Duttweiler, F; Gasaway, T M; Levin, C S

    2011-01-01

    This paper investigates the performance of 1 mm resolution Cadmium Zinc Telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3-D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06±0.39% at 511 keV thr...

  12. Iron telluride nanorods-based system for the detection of total mercury in blood

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Prathik; Lin, Zong-Hong [Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China); Liang, Chi-Te [Department of Physics, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China); Chang, Huan-Tsung, E-mail: changht@ntu.edu.tw [Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China)

    2012-12-15

    Graphical abstract: Elucidation of the detection of mercury using iron telluride nanorods (FeTe NRs), and dose-response curve for varying concentrations of Hg{sup 2+}. Highlights: Black-Right-Pointing-Pointer Iron telluride nanorods (FeTe NRs) are prepared from tellurium nanowires (Te NWs). Black-Right-Pointing-Pointer Mercury telluride nanorods (HgTe NRs) form by cation exchange reaction of FeTe NRs. Black-Right-Pointing-Pointer Fe{sup 2+} ions released catalyze the oxidation of ABTS by H{sub 2}O{sub 2}. Black-Right-Pointing-Pointer Mercury is effectively determined in blood with an LOD of 1.31 nM at S/N ratio 3. - Abstract: We have developed a simple, colorimetric iron telluride (FeTe) nanorods (NRs) based system for the detection of mercury, mainly based on the cation exchange reaction between FeTe NRs and Hg{sup 2+}. FeTe NRs (length, 105 {+-} 21 nm) react with Hg{sup 2+} to form HgTe NRs (length, 112 {+-} 26 nm) and consequently release Fe{sup 2+} ions that catalyzes the oxidation between a peroxidase substrate 2,2 Prime -azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and H{sub 2}O{sub 2}. The concentration of Fe{sup 2+} and thereby Hg{sup 2+} can be determined by measuring the absorbance of the ABTS oxidized product at 418 nm. This approach allows the detection of Hg{sup 2+}, with a limit of detection of 1.31 nM at a signal-to-noise ratio 3 and a linear range 5-100 nM (R{sup 2} = 0.99). The low-cost, simple, sensitive, and reproducible assay has been validated for the detection of Hg{sup 2+} in a blood sample (SRM 955c), with the result being in good agreement with that provided by National Institute of Standards and Technology.

  13. Te-doped cadmium telluride films fabricated by close spaced sublimation

    Science.gov (United States)

    Li, J.; Zheng, Y. F.; Xu, J. B.; Dai, K.

    2003-07-01

    Te-doped cadmium telluride (CdTe) films were deposited on ITO/glass substrates using the close spaced sublimation (CSS) method. The films were characterized by x-ray diffraction (XRD), the x-ray fixed-quantity (XRF) method, scanning electron microscopy (SEM) and the Hall effect. The XRD and SEM results show that appropriate Te doping would be favourable to the growth of CdTe crystallite. The Hall effect measurements indicate that the conductivity of CdTe films could be dramatically improved by Te doping. The work presented here suggests that p-type doping CdTe films can be produced using this deposition method.

  14. Charge Carrier Processes in Photovoltaic Materials and Devices: Lead Sulfide Quantum Dots and Cadmium Telluride

    Science.gov (United States)

    Roland, Paul

    Charge separation, transport, and recombination represent fundamental processes for electrons and holes in semiconductor photovoltaic devices. Here, two distinct materials systems, based on lead sulfide quantum dots and on polycrystalline cadmium telluride, are investigated to advance the understanding of their fundamental nature for insights into the material science necessary to improve the technologies. Lead sulfide quantum dots QDs have been of growing interest in photovoltaics, having recently produced devices exceeding 10% conversion efficiency. Carrier transport via hopping through the quantum dot thin films is not only a function of inter-QD distance, but of the QD size and dielectric media of the surrounding materials. By conducting temperature dependent transmission, photoluminescence, and time resolved photoluminescence measurements, we gain insight into photoluminescence quenching and size-dependent carrier transport through QD ensembles. Turning to commercially relevant cadmium telluride (CdTe), we explore the high concentrations of self-compensating defects (donors and acceptors) in polycrystalline thin films via photoluminescence from recombination at defect sites. Low temperature (25 K) photoluminescence measurements of CdTe reveal numerous radiative transitions due to exciton, trap assisted, and donor-acceptor pair recombination events linked with various defect states. Here we explore the difference between films deposited via close space sublimation (CSS) and radio frequency magnetron sputtering, both as-grown and following a cadmium chloride treatment. The as-grown CSS films exhibited a strong donor-acceptor pair transition associated with deep defect states. Constructing photoluminescence spectra as a function of time from time-resolved photoluminescence data, we report on the temporal evolution of this donor-acceptor transition. Having gained insight into the cadmium telluride film quality from low temperature photoluminescence measurements

  15. Seeded Physical Vapor Transport of Cadmium-Zinc Telluride Crystals: Growth and Characterization

    Science.gov (United States)

    Palosz, W.; George, M. A.; Collins, E. E.; Chen, K.-T.; Zhang, Y.; Burger, A.

    1997-01-01

    Crystals of Cd(1-x)Zn(x)Te with x = 0.2 and 40 g in weight were grown on monocrystalline cadmium-zinc telluride seeds by closed-ampoule physical vapor transport with or without excess (Cd + Zn) in the vapor phase. Two post-growth cool-down rates were used. The crystals were characterized using low temperature photoluminescence, atomic force microscopy, chemical etching, X-ray diffraction and electrical measurements. No formation of a second, ZnTe-rich phase was observed.

  16. Dielectric spectra of bismuth vanadate Bi4V2O11

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, V.N.; Pashkov, V.M.; Poplavko, IU.M.; Avakian, P.B.; Osipian, V.G. (Kievskii Politekhnicheskii Institut, Kiev (Ukrainian SSR))

    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. 12 refs.

  17. Dielectric spectra of bismuth vanadate Bi4V2O11

    Science.gov (United States)

    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.

  18. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements

    OpenAIRE

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-01-01

    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 ...

  19. Standard triple, bismuth pectin quadruple and sequential therapies for Helicobacter pylori eradication

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To compare the effectiveness of standard triple, bismuth pectin quadruple and sequential therapies for Helicobacter pylori (H. pylori ) eradication in a randomized, double-blinded, comparative clinical trial in China. METHODS: A total of 215 H. pylori -positive patients were enrolled in the study and randomly allocated into three groups: group A (n = 72) received a 10-d bismuth pectin quadruple therapy (20 mg rabeprazole bid , 1000 mg amoxicillin bid , 100 mg bismuth pectin qid , and 500 mg levofloxaci...

  20. Bismuth-Induced Raman Modes in GaP1-xBix

    Energy Technology Data Exchange (ETDEWEB)

    Christian, Theresa M.; Fluegel, Brian; Beaton, Daniel A.; Alberi, Kirstin; Mascarenhas, Angelo

    2016-10-01

    Dilute bismide semiconductor alloys are a promising material platform for optoelectronic devices due to drastic impacts of bismuth on the electronic structure of the alloy. At the same time, the details of bismuth incorporation in the lattice are not fully understood. In this work, we conduct Raman scattering spectroscopy on GaP1- x Bi x epilayers grown by molecular beam epitaxy (MBE) and identify several bismuth-related Raman features including gap vibration modes at 296, 303, and 314 cm-1. This study paves the way for more detailed analysis of the local symmetry at bismuth incorporation sites in the dilute bismide alloy regime.

  1. Antibacterial effects of Bismuth compounds and it synergy with Tetracycline and Metronidazole on Helicobacter Pylori

    Directory of Open Access Journals (Sweden)

    Rajabie A

    1997-04-01

    Full Text Available Bismuth salts and different antimicrobials including Metonidazole & Tetracyclines were used in the assessment of inhibition zone of Helicobacter pylori cultures on solid media. Antibiotics were used or in combined in order to find out their possible synergistic effects. It was showed that: only Bismuth substrate and not then salts have antibacterial effects on Helicobacter pylori and also on the other bacteria such as staphylococci; salmonella and brulla. In addition, only Bismuth substrances showed remarkable synergistic effects with antimicrobial drugs against Helicobacter pylori. Therefore the data obtained from this investigation confirm previously known effect of combination antibiotic therapy including Bismuth compounds in eradicating Helicobacter pylori.

  2. Elimination of the beam effect on channeling dips of bismuth implanted in silicon

    Science.gov (United States)

    Wagh, A. G.; Radhakrishnan, S.; Gaonkar, S. G.; Kansara, M. J.

    1980-01-01

    The effect of the analysing He + ion beam has been eliminated from channeling measurements on Si(Bi) by extrapolating the plot of normalised yield against He + dose to zero ion dose. The magnitude of the beam effect varies with the angle of incidence, being minimum for beam incidence along the crystallographic axis. The axial channeling dips thus obtained exhibit similar minimum yields for bismuth and silicon. The bismuth dips are, however, narrower than for silicon. The planar channeling experiments, on the other hand, yield nearly identical bismuth and silicon dips. The results indicate that the bismuth atom occupies the substitutional site in silicon, but the lattice is strained in its vicinity.

  3. Preparation of high-purity bismuth by sulphur deleadization in vacuum distillation

    Institute of Scientific and Technical Information of China (English)

    熊利芝; 何则强; 刘文萍; 麻成金; 戴永年

    2004-01-01

    The feasibility of separation of impurities in refined bismuth and sulphur deleadization with vacuum distillation was studied theoretically. Experimental studies on sulphur deleadization were carried out under vacuum.The influences of amount of sulphur, distillation temperature, vacuum degree and distillation time on deleadization were investigated and an optimal technical condition was achieved. The content of lead in refined bismuth can be decreased from 30 μg/g to 0.21 μg/g, which has reached the level of "5N" high-purity bismuth. Other impurities in refined bismuth can be also removed effectively under certain conditions.

  4. Nanophotonic Modulator with Bismuth Ferrite as Low-loss Switchable Material

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2015-01-01

    We propose a nanophotonic waveguide modulator with bismuth ferrite as a tunable material. Due to near-zero losses in bismuth ferrite, modulation with up to 20 dB/μm extinction ratio and 12 μm propagation length is achieved.......We propose a nanophotonic waveguide modulator with bismuth ferrite as a tunable material. Due to near-zero losses in bismuth ferrite, modulation with up to 20 dB/μm extinction ratio and 12 μm propagation length is achieved....

  5. Bismuth-induced Raman modes in GaP1- x Bi x

    Science.gov (United States)

    Christian, Theresa M.; Fluegel, Brian; Beaton, Daniel A.; Alberi, Kirstin; Mascarenhas, Angelo

    2016-10-01

    Dilute bismide semiconductor alloys are a promising material platform for optoelectronic devices due to drastic impacts of bismuth on the electronic structure of the alloy. At the same time, the details of bismuth incorporation in the lattice are not fully understood. In this work, we conduct Raman scattering spectroscopy on GaP1- x Bi x epilayers grown by molecular beam epitaxy (MBE) and identify several bismuth-related Raman features including gap vibration modes at 296, 303, and 314 cm-1. This study paves the way for more detailed analysis of the local symmetry at bismuth incorporation sites in the dilute bismide alloy regime.

  6. Optimal biliary drainage for inoperable Klatskin's tumor based on Bismuth type

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate differences in the effects of biliary drainage procedures in patients with inoperable Klatskin's tumor based on Bismuth type, considering endoscopic retrograde biliary drainage (ERBD), external percutaneous transhepatic biliary drainage (EPTBD) and internal biliary stenting via the PTBD tract (IPTBD).METHODS: The initial success rate, cumulative patency rate, and complication rate were compared retrospectively, according to the Bismuth type and ERBD,EPTBD, and IPTBD. Patency was defined as the duration for adequate initial bile drainage or to the point of the patient's death associated with inadequate drainage.RESULTS: One hundred thirty-four patients (93 men,41 women; 21 Bismuth type Ⅱ, 47 Ⅲ, 66 Ⅳ; 34 ERBD,66 EPTBD, 34 IPTBD) were recruited. There were no differences in demographics among the groups.Adequate initial relief of jaundice was achieved in 91% of patients without a significant difference in the results among different procedures or Bismuth types. The cumulative patency rates for ERBD and IPTBD were better than those for EPTBD with Bismuth type Ⅲ.IPTBD provided an excellent response for Bismuth type Ⅳ. However, there was no difference in the patency rate among drainage procedures for Bismuth type Ⅱ.Procedure-related cholangitis occurred less frequently with EPTBD than with ERBD and IPTBD.CONCLUSION: ERBD is recommended as the firstline drainage procedure for the palliation of jaundice in patients with inoperable Klatskin's tumor of Bismuth type Ⅱ or Ⅲ, but IPTBD is the best option for Bismuth type Ⅳ.

  7. Bismuth Ferrite for Active Control of Surface Plasmon Polariton Modes

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose and investigate several layouts of m etal-insulator-metal waveguide with active core which can be utilized for dynamic switching in photonic integrated circuits. The active material, bismuth ferrite (BiFeO3), is sandwiched between metal plates and changes i ts refractive index through ...... partial switching of ferroelectric domain orientati on under applied voltage. Both phase and amplitude modulations are envisaged.......We propose and investigate several layouts of m etal-insulator-metal waveguide with active core which can be utilized for dynamic switching in photonic integrated circuits. The active material, bismuth ferrite (BiFeO3), is sandwiched between metal plates and changes i ts refractive index through...

  8. Large area bismuth absorbers for X-ray microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Vaillancourt, J.E. E-mail: vaillancourt@wisp.physics.wisc.edu; Allen, C.A.; Brekosky, R.; Dosaj, A.; Galeazzi, M.; Kelley, R.; Liu, D.; McCammon, D.; Porter, F.S.; Rocks, L.E.; Sanders, W.T.; Stahle, C.K

    2004-03-11

    Two challenges facing the use of large area (2 mmx2 mm) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3-0.6 J K{sup -1} m{sup -3} at 100 mK. These absorbers also exhibit response variations as phonons created by an X-ray event at an absorber edge will take longer to propagate to the thermometer attachment point than those at the absorber center. This effect may degrade the detector's energy resolution if the propagation time is not very short compared to the thermometer time constant. We show that the response of the largest absorber varies by {approx}4% across its area.

  9. Ab initio electronic structure and optical conductivity of bismuth tellurohalides

    CERN Document Server

    Schwalbe, Sebastian; Starke, Ronald; Schober, Giulio A H; Kortus, Jens

    2016-01-01

    We investigate the electronic structure, dielectric and optical properties of bismuth tellurohalides BiTeX (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. , Makhnev et al. , and Rusinov et al. . 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.

  10. Low temperature Hall effect in bismuth chalcogenides thin films

    OpenAIRE

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

    2016-01-01

    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 purely phenomenologi...

  11. Modular Lead-Bismuth Fast Reactors in Nuclear Power

    OpenAIRE

    Vladimir Petrochenko; Georgy Toshinsky

    2012-01-01

    On the basis of the unique experience of operating reactors with heavy liquid metal coolant–eutectic lead-bismuth alloy in nuclear submarines, the concept of modular small fast reactors SVBR-100 for civilian nuclear power has been developed and validated. The features of this innovative technology are as follows: a monoblock (integral) design of the reactor with fast neutron spectrum, which can operate using different types of fuel in various fuel cycles including MOX fuel in a self-providing...

  12. Telluride buried channel waveguides operating from 6 to 20 μm for photonic applications

    Science.gov (United States)

    Vigreux, C.; Escalier, R.; Pradel, A.; Bastard, L.; Broquin, J.-E.; Zhang, X.; Billeton, T.; Parent, G.; Barillot, M.; Kirschner, V.

    2015-11-01

    One of the technological challenges of direct observation of extra-solar planets by nulling interferometry is the development of a modal filter operating from 6 to 20 μm. In the present paper a candidate technology for the fabrication of such modal filters is presented: Integrated Optics. A solution based on all-telluride buried channel waveguides is considered. In the proposed waveguides, vertical guiding of light is achieved by a 15 μm-thick Te83Ge17 core film deposited onto a lower-index Te75Ge15Ga10 substrate, and covered by a 15 μm-thick Te76Ge24 superstrate. Horizontal guiding of light is obtained by modifying the geometry of the core layer by ion beam etching. As this stage, all-telluride buried channel waveguide prototypes demonstrate light guiding and transmission from 2 to 20 μm. The validity of the technology and the good quality of the fabrication process, in particular the input and output facets surface finish are thus confirmed. These results consolidate the potential of Te-based integrated optics components for nulling interferometry.

  13. A density-functional study on the electronic and vibrational properties of layered antimony telluride

    Science.gov (United States)

    Stoffel, Ralf P.; Deringer, Volker L.; Simon, Ronnie E.; Hermann, Raphaël P.; Dronskowski, Richard

    2015-03-01

    We present a comprehensive survey of electronic and lattice-dynamical properties of crystalline antimony telluride (Sb2Te3). In a first step, the electronic structure and chemical bonding have been investigated, followed by calculations of the atomic force constants, phonon dispersion relationships and densities of states. Then, (macroscopic) physical properties of Sb2Te3 have been computed, namely, the atomic thermal displacement parameters, the Grüneisen parameter γ, the volume expansion of the lattice, and finally the bulk modulus B. We compare theoretical results from three popular and economic density-functional theory (DFT) approaches: the local density approximation (LDA), the generalized gradient approximation (GGA), and a posteriori dispersion corrections to the latter. Despite its simplicity, the LDA shows excellent performance for all properties investigated—including the Grüneisen parameter, which only the LDA is able to recover with confidence. In the absence of computationally more demanding hybrid DFT methods, the LDA seems to be a good choice for further lattice dynamical studies of Sb2Te3 and related layered telluride materials.

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

    Science.gov (United States)

    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.

  15. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    Energy Technology Data Exchange (ETDEWEB)

    Exner, Jörg, E-mail: Functional.Materials@Uni-Bayreuth.de [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany); Fuierer, Paul [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Moos, Ralf [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany)

    2014-12-31

    Bismuth vanadate, Bi{sub 4}V{sub 2}O{sub 11}, and related compounds with various metal (Me) substitutions, Bi{sub 4}(Me{sub x}V{sub 1−x}){sub 2}O{sub 11−δ}, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated.

  16. Bismuth pyrochlore-based thin films for dielectric energy storage

    Science.gov (United States)

    Michael, Elizabeth K.

    The drive towards the miniaturization of electronic devices has created a need for dielectric materials with large energy storage densities. These materials, which are used in capacitors, are a critical component in many electrical systems. Here, the development of dielectric energy storage materials for pulsed power applications, which require materials with the ability to accumulate a large amount of energy and then deliver it to the system rapidly, is explored. The amount of electrostatic energy that can be stored by a material is a function of the induced polarization and the dielectric breakdown strength of the material. An ideal energy storage dielectric would possess a high relative permittivity, high dielectric breakdown strength, and low loss tangent under high applied electric fields. The bismuth pyrochlores are a compositionally tunable family of materials that meet these requirements. Thin films of cubic pyrochlore bismuth zinc niobate, bismuth zinc tantalate, and bismuth zinc niobate tantalate, were fabricated using a novel solution chemistry based upon the Pechini method. This solution preparation is advantageous because it avoids the use of teratogenic solvents, such as 2-methoxyethanol. Crystalline films fabricated using this solution chemistry had very small grains that were approximately 27 nm in lateral size and 35 nm through the film thickness. Impedance measurements found that the resistivity of the grain boundaries was two orders of magnitude higher than the resistivity of the grain interior. The presence of many resistive grain boundaries impeded conduction through the films, resulting in high breakdown strengths for these materials. In addition to high breakdown strengths, this family of materials exhibited moderate relative permittivities of 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

  17. Study of barium bismuth titanate prepared by mechanochemical synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2009-01-01

    Full Text Available Barium-bismuth titanate, BaBi4Ti4O15 (BBT, a member of Aurivillius bismuth-based layer-structure perovskites, was prepared from stoichiometric amounts of barium titanate and bismuth titanate obtained via mechanochemical synthesis. Mechanochemical synthesis was performed in air atmosphere in a planetary ball mill. The reaction mechanism of BaBi4Ti4O15 and the preparation and characteristics of BBT ceramic powders were studied using XRD, Raman spectroscopy, particle analysis and SEM. The Bi-layered perovskite structure of BaBi4Ti4O15 ceramic forms at 1100 °C for 4 h without a pre-calcination step. The microstructure of BaBi4Ti4O15 exhibits plate-like grains typical for the Bi-layered structured material and spherical and polygonal grains. The Ba2+ addition leads to changes in the microstructure development, particularly in the change of the average grain size.

  18. Resistivity and Seebeck coefficient measurements of a bismuth microwire array

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Y. [Graduate School of Science and Engineering, Saitama University, 338-8570 (Japan)]. E-mail: ishikawa@kan.env.gse.saitama-u.ac.jp; Hasegawa, Y. [Graduate School of Science and Engineering, Saitama University, 338-8570 (Japan); Morita, H. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Kurokouchi, A. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Wada, K. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Komine, T. [Department of Media and Telecommunications Engineering, Ibaraki University, 316-8511 (Japan); Nakamura, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5252 (Japan)

    2005-11-01

    The resistivity and Seebeck coefficient of a bismuth microwire array (wire diameter: 25 {mu}m) were successfully measured from 25 to 300 K. To eliminate the influence of the contact resistance between the wire edges of the microwire array and copper electrodes, the titanium (100 nm)/copper (500 nm) film layers were deposited as interlayer on the wire edge by ion plating method. Copper electrodes were glued by using Pb-Sn solder. The resistivity and the Seebeck coefficient at 300 K were approximately 1.8x10{sup -6} {omega}m and -54x10{sup -6} V/K, respectively. The value of the resistivity and the Seebeck coefficient were in good agreement with those of bulk polycrystalline bismuth reported previously. Thus, the effects of the contact resistance for the microwire array were almost resolved, and the chemical reaction of the Pb-Sn solder and bismuth was prevented by using the thin-film layer. The technique is expected to be applicable to nanowire arrays as well.

  19. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

  20. 76 FR 46288 - Adequacy Determination for Colorado Springs, Cañon City, Greeley, Pagosa Springs, and Telluride...

    Science.gov (United States)

    2011-08-02

    ... AGENCY Adequacy Determination for Colorado Springs, Ca on City, Greeley, Pagosa Springs, and Telluride... Carbon Monoxide Attainment/Maintenance Plan Colorado Springs Attainment/ Maintenance Area'' and ``Revised...,'' ``Final Revised PM10 Maintenance Plan for the Pagosa Springs Attainment/Maintenance Area,'' and...

  1. Facile preparation of carbon wrapped copper telluride nanowires as high performance anodes for sodium and lithium ion batteries

    Science.gov (United States)

    Yu, Hong; Yang, Jun; Geng, Hongbo; Chao Li, Cheng

    2017-04-01

    Uniform carbon wrapped copper telluride nanowires were successfully prepared by using an in situ conversion reaction. The length of these nanowires is up to several micrometers and the width is around 30–40 nm. The unique one dimensional structure and the presence of conformal carbon coating of copper telluride greatly accommodate the large volumetric changes during cycling, significantly increase the electrical conductivity and reduce charge transfer resistance. The copper telluride nanowires show promising performance in a lithium ion battery with a discharge capacity of 130.2 mA h g‑1 at a high current density of 6.0 A g‑1 (26.74 C) and a stable cycling performance of 673.3 mA h g‑1 during the 60th cycle at 100 mA g‑1. When evaluated as anode material for a sodium ion battery, the copper telluride nanowires deliver a reversible capacity of 68.1 mA h g‑1 at 1.0 A g‑1 (∼4.46 C) and have a high capacity retention of 177.5 mA h g‑1 during the 500th cycle at 100 mA g‑1.

  2. Effect of O-vacancies on magnetic properties of bismuth ferrite nanoparticles by solution evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Afzal, A.M., E-mail: Amirafzal461@gmail.com [Department of Physics, GC University, Faisalabad 38000 (Pakistan); Umair, M., E-mail: umairranwerr@gmail.com [Department of Physics, GC University, Faisalabad 38000 (Pakistan); Dastgeer, G., E-mail: dtedastgeer@gmail.com [Department of Physics, University of Agriculture, Faisalabad 38000 (Pakistan); Rizwan, M., E-mail: h.rizwan70@gmail.com [Department of Physics, GC University, Faisalabad 38000 (Pakistan); Yaqoob, M.Z., E-mail: zeeshaan32@gmail.com [Department of Physics, GC University, Faisalabad 38000 (Pakistan); Rashid, R., E-mail: rashid.kanwar22@gmail.com [Department of Physics, University of Agriculture, Faisalabad 38000 (Pakistan); Munir, H.S., E-mail: sadiamunir.cute@gmail.com [Department of Physics, GC University, Faisalabad 38000 (Pakistan)

    2016-02-01

    Bismuth ferrite is a multiferroic material which shows high magnetization and polarization at room temperature. In present work, the effect of Oxygen (O) vacancies on magnetic properties of bismuth ferrite nanoparticles is studied. Bismuth ferrite nanoparticles (BiFeO{sub 3}) were synthesized by solution evaporation method (SEM) at room temperature. The sample was annealed under two different atmospheres such as in air and oxygen, to check the effect of O-vacancies on magnetic properties. The average crystallite size of Bismuth ferrite nanoparticles (NPs) as calculated by X-ray diffraction (XRD) falls in the range of 23–32 nm and 26–39 nm for the case of air and oxygen respectively. The crystallite size of bismuth ferrite nanoparticles increases as the temperature was varied from 450 °C to 650 °C. Further the influence of annealing temperature on the magnetic properties of the bismuth ferrite nanoparticles was also observed. It was concluded that the magnetic properties of Bismuth ferrite nanoparticles are directly interconnected to annealing atmosphere and annealing temperature. The magnetic properties were increased in the case of oxygen annealing, which actually leads in our case to an improvement of the crystallinity. - Highlights: • Bismuth ferrite was synthesized by solution evaporation method. • The effect of different annealing atmosphere on magnetic properties was studied. • The magnetic properties dramatically increased in case of Oxygen annealing. • The influence of crystalline size on magnetic properties was studied. • The magnetization was decreased as the temperature and crystallite size increased.

  3. Electronic Properties of Tin and Bismuth from Angular Correlation of Annihilation Photons

    DEFF Research Database (Denmark)

    Mogensen, O.E.; Trumpy, Georg

    1969-01-01

    A linear slit setup has been used to obtain results of angular-correlation measurements in (a) tin single crystals in three orientations: [001], [100], and [110], (b) bismuth single crystals in four orientations: [111], [100], [1¯10], and [2¯1¯1], (c) solid and liquid tin and bismuth, and (d) def...

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

    Science.gov (United States)

    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.

  5. Selective oxidation of propylene to acrolein by silica-supported bismuth molybdate catalysts

    DEFF Research Database (Denmark)

    Duc, Duc Truong; Ha, Hanh Nguyen; Fehrmann, Rasmus

    2011-01-01

    Silica-supported bismuth molybdate catalysts have been prepared by impregnation, structurally characterized and examined as improved catalysts for the selective oxidation of propylene to acrolein. Catalysts with a wide range of loadings (from 10 to 90 wt%) of beta bismuth molybdate (β-Bi2Mo2O9...

  6. Effects of In Vitro Antibiotic Resistance on Treatment: Bismuth-Containing Regimens

    Directory of Open Access Journals (Sweden)

    Naoki Chiba

    2000-01-01

    Full Text Available Bismuth compounds remain useful for Helicobacter pylori eradication therapy. These include colloidal bismuth subcitrate (CBS, bismuth subsalicylate (BSS and, most recently, ranitidine bismuth citrate (RBC. CBS appears to prevent the development of imidazole resistance when coadministered with nitroimidazoles. Traditional triple therapy with bismuth, metronidazole and tetracycline or amoxicillin (BMT/A only partially overcomes metronidazole resistance. However, the addition of a PPI to bismuth triple therapy largely overcomes established metronidazole resistance if treatment is given for at least one week or more. When RBC rather than PPI is used with clarithromycin, this dual regimen appears to be more effective in preventing the development of secondary clarithromycin resistance. The triple combination of RBC, metronidazole and clarithromycin appears to be effective against metronidazole resistant strains of H pylori. Thus, overall, there is some evidence that bismuth compounds may prevent the development of antibiotic resistance and that existing antibiotic resistance may at least be partially overcome in vitro and in vivo. With the growing emergence of H pylori resistance to metronidazole and clarithromycin, further research to clarify the role of bismuth compounds is required.

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

    Science.gov (United States)

    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.

  8. Synthesis of cadmium telluride quantum wires and the similarity of their band gaps to those of equidiameter cadmium telluride quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lin-Wang; Sun, Jianwei; Wang, Lin-Wang; Buhro, William E.

    2008-07-11

    High-quality colloidal CdTe quantum wires having purposefully controlled diameters in the range of 5-11 nm are grown by the solution-liquid-solid (SLS) method, using Bi-nanoparticle catalysts, cadmium octadecylphosphonate and trioctylphosphine telluride as precursors, and a TOPO solvent. The wires adopt the wurtzite structure, and grow along the [002] direction (parallel to the c axis). The size dependence of the band gaps in the wires are determined from the absorption spectra, and compared to the experimental results for high-quality CdTe quantum dots. In contrast to the predictions of an effective-mass approximation, particle-in-a-box model, and previous experimental results from CdSe and InP dot-wire comparisons, the band gaps of CdTe dots and wires of like diameter are found to be experimentally indistinguishable. The present results are analyzed using density functional theory under the local-density approximation by implementing a charge-patching method. The higher-level theoretical analysis finds the general existence of a threshold diameter, above which dot and wire band gaps converge. The origin and magnitude of this threshold diameter is discussed.

  9. Controlled cadmium telluride thin films for solar cell applications (emerging materials systems for solar cell applications). Quarterly progress report No. 1, April 9-July 8, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Vedam, K.

    1979-08-01

    Preparation and properties of cadmium telluride thin films for use in solar cells are studied. CdTe sputter deposition, crystal doping, and carrier typing are discussed. Future experimental plans are described. (WHK)

  10. An atomic absorption spectrometric method for the determination of phosphorus in foodstuffs using the bismuth phosphomolybdate complex

    Directory of Open Access Journals (Sweden)

    LJILJANA V. MIHAJLOVIC

    2000-06-01

    Full Text Available A new indirect AAS method using the bismuth phosphomolybdate complex for the determination of phosphorus in foodstuffs is suggested. The bismuth phosphomolybdate complex in acid medium was extacted with isobutyl methylketone and the phosphorus was determined through bismuth in an air/acetylene flame by utilising the 223.06 nm resonance line of bismuth. The interference caused by antimony and titanium can be neglected in the presence of excess of bismuth. The detection limit of the method is 0.008 mg/mL of phosphorus.

  11. Structure and Surface Analysis of SHI Irradiated Thin Films of Cadmium Telluride

    Directory of Open Access Journals (Sweden)

    Neelam Pahwa

    2012-10-01

    Full Text Available Cadmium Telluride (CdTe thin films grown by thermal evaporation on quartz substrates were irradiated with swift (100 MeV Ni + 4 ions at various fluences in the range 1011 – 1013 cm – 2. The modification in structure and surface morphology has been analyzed as a function of fluence using XRD and AFM techniques. The XRD showed a reduction in peak intensity and grain size with increasing fluence. The AFM micrographs of irradiated thin films show small spherical nanostructures. In addition to direct imaging, AFM profile data enable to derive the Power Spectral Density (PSD of the surface roughness. In the present work PSD spectra computed from AFM data were used for studying the surface morphology of films. The PSD curves were fitted with an appropriate analytic function and characteristic parameters were deduced and discussed in order to compare film morphology with varying fluence levels.

  12. Experiments and Monte Carlo modeling of a higher resolution Cadmium Zinc Telluride detector for safeguards applications

    Science.gov (United States)

    Borella, Alessandro

    2016-09-01

    The Belgian Nuclear Research Centre is engaged in R&D activity in the field of Non Destructive Analysis on nuclear materials, with focus on spent fuel characterization. A 500 mm3 Cadmium Zinc Telluride (CZT) with enhanced resolution was recently purchased. With a full width at half maximum of 1.3% at 662 keV, the detector is very promising in view of its use for applications such as determination of uranium enrichment and plutonium isotopic composition, as well as measurement on spent fuel. In this paper, I report about the work done with such a detector in terms of its characterization. The detector energy calibration, peak shape and efficiency were determined from experimental data. The data included measurements with calibrated sources, both in a bare and in a shielded environment. In addition, Monte Carlo calculations with the MCNPX code were carried out and benchmarked with experiments.

  13. Role of Van der Waals interactions in determining the structure of liquid tellurides

    Science.gov (United States)

    Micoulaut, Matthieu; Flores-Ruiz, Hugo; Coulet, Vanessa; Piarristeguy, Andrea; Johnson, Mark; Cuello, Gabriel; Pradel, Annie

    The simulation of tellurides using standard density functional (DFT) theory based molecular dynamics usually leads to an overestimation of the bond distances and a noticeable mismatch between theory and experiments when e.g. structure functions are being directly compared. Here, the structural properties of several compositions of Ge-Te and Ge-Sb-Te liquids are studied from a combination of neutron diffraction and DFT-based molecular dynamics. Importantly, we find an excellent agreement in the reproduction of the structure in real and reciprocal spaces, resulting from the incorporation of dispersion forces in the simulation. We then investigate structural properties including structure factors, pair distribution functions, angular distributions, coordination numbers, neighbor distributions, and compare our results with experimental findings. References:Physical Review B 92, 134205 (2015)Physical Review B 89, 174205 (2014)Physical Review B 90, 094207 (2014) Support from Agence Nationale de la Recherche (ANR) (Grant No. ANR-11-BS08-0012) is gratefully acknowledged.

  14. New Insights into High-Performance Thermoelectric Tellurides from ^125Te NMR Spectroscopy

    Science.gov (United States)

    Levin, E. M.; Hu, Y.-Y.; Cook, B. A.; Harringa, J. L.; Schmidt-Rohr, K.; Kanatzidis, M. G.

    2009-11-01

    Thermoelectric materials are widely used for direct transformation of heat to electricity (Seebeck effect) and for solid state refrigeration (Peltier effect). Efforts to increase the efficiency of high-performance thermoelectrics, which include narrow-gap, doped tellurium-based semiconductors, require detailed knowledge of their local structure and bonding. We have used ^125Te nuclear magnetic resonance (NMR) as a local probe for obtaining better understanding of these high-performance thermoelectric tellurides, specifically PbTe doped with Ag and Sb (LAST materials) and GeTe doped with Ag and Sb (TAGS materials). The resonance frequencies and line shapes of the NMR spectra, as well as spin-lattice relaxation times and chemical shift anisotropies are highly sensitive to the composition and synthesis conditions of LAST and TAGS materials, enabling studies of the local composition, distortion, bonding, and carrier concentration. Several intriguing phenomena including electronic inhomogeneity and local distortions of the crystal lattice have been observed by NMR.

  15. Nanoscale arrays of antimony telluride single crystals by selective chemical vapor deposition

    Science.gov (United States)

    Huang, Ruomeng; Benjamin, Sophie L.; Gurnani, Chitra; Wang, Yudong; Hector, Andrew L.; Levason, William; Reid, Gillian; De Groot, C. H. (Kees)

    2016-01-01

    Arrays of individual single nanocrystals of Sb2Te3 have been formed using selective chemical vapor deposition (CVD) from a single source precursor. Crystals are self-assembled reproducibly in confined spaces of 100 nm diameter with pitch down to 500 nm. The distribution of crystallite sizes across the arrays is very narrow (standard deviation of 15%) and is affected by both the hole diameter and the array pitch. The preferred growth of the crystals in the orientation along the diagonal of the square holes strongly indicates that the diffusion of adatoms results in a near thermodynamic equilibrium growth mechanism of the nuclei. A clear relationship between electrical resistivity and selectivity is established across a range of metal selenides and tellurides, showing that conductive materials result in more selective growth and suggesting that electron donation is of critical importance for selective deposition. PMID:27283116

  16. Chemical pressure and hidden one-dimensional behavior in rare earth tri-telluride

    Energy Technology Data Exchange (ETDEWEB)

    Sacchetti, A.; Degiorgi, L.; /Zurich, ETH; Giamarchi, T.; /Geneva U.; Ru, N.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    We report on the first optical measurements of the rare-earth tri-telluride charge-density-wave systems. Our data, collected over an extremely broad spectral range, allow us to observe both the Drude component and the single-particle peak, ascribed to the contributions due to the free charge carriers and to the charge-density-wave gap excitation, respectively. The data analysis displays a diminishing impact of the charge-density-wave condensate on the electronic properties with decreasing lattice constant across the rare-earth series. We propose a possible mechanism describing this behavior and we suggest the presence of a one-dimensional character in these two-dimensional compounds. We also envisage that interactions and umklapp processes might play a relevant role in the formation of the charge-density-wave state in these compounds.

  17. Improved performance of silicon nanowire/cadmium telluride quantum dots/organic hybrid solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Zhaoyun [National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu Province (China); Xu, Ling, E-mail: xuling@nju.edu.cn [National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Renqi; Xue, Zhaoguo; Wang, Hongyu; Xu, Jun; Yu, Yao; Su, Weining; Ma, Zhongyuan; Chen, Kunji [National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2015-04-15

    Highlights: • We introduce an intermediate cadmium telluride quantum dots (CdTe QDs) layer between the organic with silicon nanowires of hybrid solar cells as a down-shifting layer. • The hybrid solar cell got the maximum short circuit current density of 33.5 mA/cm{sup 2}, getting an increase of 15.1% comparing to solar cell without CdTe QDs. • The PCE of the hybrid solar cells with CdTe QDs layer increases 28.8%. - Abstract: We fabricated silicon nanowire/cadmium telluride quantum dots (CdTe QDs)/organic hybrid solar cells and investigated their structure and electrical properties. Transmission electron microscope revealed that CdTe QDs were uniformly distributed on the surface of the silicon nanowires, which made PEDOT:PSS easily filled the space between SiNWs. The current density–voltage (J–V) characteristics of hybrid solar cells were investigated both in dark and under illumination. The result shows that the performance of the hybrid solar cells with CdTe QDs layer has an obvious improvement. The optimal short-circuit current density (J{sub sc}) of solar cells with CdTe QDs layer can reach 33.5 mA/cm{sup 2}. Compared with the solar cells without CdTe QDs, J{sub sc} has an increase of 15.1%. Power conversion efficiency of solar cells also increases by 28.8%. The enhanced performance of the hybrid solar cells with CdTe QDs layers are ascribed to down-shifting effect of CdTe QDs and the modification of the silicon nanowires surface with CdTe QDs. The result of our experiments suggests that hybrid solar cells with CdTe QDs modified are promising candidates for solar cell application.

  18. Yttrium bismuth titanate pyrochlore mixed oxides for photocatalytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Merka, Oliver

    2012-10-18

    In this work, the sol-gel synthesis of new non-stoichiometric pyrochlore titanates and their application in photocatalytic hydrogen production is reported. Visible light response is achieved by introducing bismuth on the A site or by doping the B site by transition metal cations featuring partially filled d orbitals. This work clearly focusses on atomic scale structural changes induced by the systematical introduction of non-stoichiometry in pyrochlore mixed oxides and the resulting influence on the activity in photocatalytic hydrogen production. The materials were characterized in detail regarding their optical properties and their atomic structure. The pyrochlore structure tolerates tremendous stoichiometry variations. The non-stoichiometry in A{sub 2}O{sub 3} rich compositions is compensated by distortions in the cationic sub-lattice for the smaller Y{sup 3+} cation and by evolution of a secondary phase for the larger Bi{sup 3+} cation on the A site. For TiO{sub 2} rich compositions, the non-stoichiometry leads to a special vacancy formation in the A and optionally O' sites. It is shown that pyrochlore mixed oxides in the yttrium bismuth titanate system represent very active and promising materials for photocatalytic hydrogen production, if precisely and carefully tuned. Whereas Y{sub 2}Ti{sub 2}O{sub 7} yields stable hydrogen production rates over time, the bismuth richer compounds of YBiTi{sub 2}O{sub 7} and Bi{sub 2}Ti{sub 2}O{sub 7} are found to be not stable under irradiation. This drawback is overcome by applying a special co-catalyst system consisting of a precious metal core and a Cr{sub 2}O{sub 3} shell on the photocatalysts.

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

    Science.gov (United States)

    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.

  20. Conduction mechanism in bismuth silicate glasses containing titanium

    Science.gov (United States)

    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.

  1. Solution combustion synthesis and characterization of nanosized bismuth ferrite

    Science.gov (United States)

    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.

  2. Coherent phonon coupling to individual Bloch states in photoexcited bismuth.

    Science.gov (United States)

    Papalazarou, E; Faure, J; Mauchain, J; Marsi, M; Taleb-Ibrahimi, A; Reshetnyak, I; van Roekeghem, A; Timrov, I; Vast, N; Arnaud, B; Perfetti, L

    2012-06-22

    We investigate the temporal evolution of the electronic states at the bismuth (111) surface by means of time- and angle-resolved photoelectron spectroscopy. The binding energy of bulklike bands oscillates with the frequency of the A(1g) phonon mode, whereas surface states are insensitive to the coherent displacement of the lattice. A strong dependence of the oscillation amplitude on the electronic wave vector is correctly reproduced by ab initio calculations of electron-phonon coupling. Besides these oscillations, all the electronic states also display a photoinduced shift towards higher binding energy whose dynamics follows the evolution of the electronic temperature.

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

    Science.gov (United States)

    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.

  4. Concentration Quenching in Erbium Doped Bismuth Silicate Glasses

    Institute of Scientific and Technical Information of China (English)

    DAI Shi-Xun; XU Tie-Feng; NIE Qiu-Hua; SHEN Xiang; WANG Xun-Si

    2006-01-01

    @@ Er2 O3-doped bismuth silicate glasses are prepared by the conventional melt-quenching method, and the Er3+ : 4 I13/2 → 4I15/2 fluorescence properties are studied for different Er3+ concentrations. Infrared spectra are measured to estimate the exact content of OH- groups in the samples. Based on the electric dipole-dipole interaction theory,the interaction parameter CEr,Er for the migration rate of Er3+ :4 I13/2 → 4 I13/2 in proposed glasses is calculated.

  5. Kinetics of Propagating Phase Transformation in Compressed Bismuth

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements.

    Science.gov (United States)

    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.

  7. Investigation of corrosion, water reaction, polonium evaporation and bismuth resource in liquid metal lead-bismuth technology

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Hideki; Takizuka, Takakazu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kitano, Teruaki [Mitsui Shipbuilding and Engineering Co. Ltd., Tokyo (Japan)

    2000-10-01

    Lead-bismuth is the first candidate material for liquid metal target find coolant of fueled blanket system in accelerator-driven system (ADS) studied at JAERI. Advantages of the lead-bismuth utilization are non-active material, very low capture cross section, low melting point of 125degC and high boiling point of 1670degC, and beside coolant void reactivity become negative. But problems are due to the high corrosivity to most of the structural materials and the corrosive data are scarcity. In this report, corrosivity, reaction with water, thermal-hydraulics, chemical toxicity etc. are studied by investigating some facilities utilized and researched really for lead or lead-bismuth. And, furthermore, polonium evaporation rate and bismuth resource are investigated. Main results obtained are as follows: (1) In a refinery, there are enough employment experience for liquid Pb-Bi in period of about 17 years and not corrosion for the thermal conductive materials (1Cr-0.5Mo steel) used under the condition of natural convection with temperature around 400degC. (2) In Russia, extensive experience in the use as Russian submarines and in R and D during about 50 years are available. And as a result, it will be able to lead approximately zero corrosion for Cr-Si materials by adjusting oxygen film with oxygen concentration control between 10{sup -7} to 10{sup -5}% mass. However, the corrosion data are not enough systematically collected involving them in radiation dose field. (3) In liquid-dropping experiment, it is shown that interaction between water and high temperature liquid Pb-Bi is reduced steeply with rising of atmosphere pressure. But, in order to design the second circuit removal model of ADS, the interaction should be evaluated by water continuous injection experiment. (4) Polonium forms PbPo in Pb-Bi, and the evaporation rate become less three factor than that of Po, and furthermore, the rate decreases in the atmosphere. The effects of Po on employee and environment

  8. Magnetic anisotropies in ultrathin bismuth iron garnet films

    Energy Technology Data Exchange (ETDEWEB)

    Popova, Elena, E-mail: popova@physique.uvsq.fr [Groupe d' Etude de la Matière Condensée (GEMaC), CNRS/Université de Versailles-Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles (France); Franco Galeano, Andres Felipe [Laboratoire PROcédés, Matériaux et Energie Solaire (PROMES), CNRS/Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan (France); Deb, Marwan [Groupe d' Etude de la Matière Condensée (GEMaC), CNRS/Université de Versailles-Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles (France); Warot-Fonrose, Bénédicte [Centre d' Elaboration de Matériaux et d' Etudes Structurales (CEMES), CNRS, 29 rue Jeanne Marvig, 31055 Toulouse (France); Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS–Universidad de Zaragoza (Spain); Kachkachi, Hamid [Laboratoire PROcédés, Matériaux et Energie Solaire (PROMES), CNRS/Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan (France); Gendron, François [Institut des NanoSciences de Paris (INSP), CNRS/Université Pierre et Marie Curie-Paris 6, 4 place Jussieu, Boîte courrier 840, 75252 Paris Cedex 05 (France); Ott, Frédéric [Laboratoire Léon Brillouin (LLB), CNRS/CEA, Bâtiment 563, CEA Saclay, 91191 Gif sur Yvette Cedex (France); and others

    2013-06-15

    Ultrathin bismuth iron garnet Bi{sub 3}Fe{sub 5}O{sub 12} films were grown epitaxially on (001)-oriented gadolinium gallium garnet substrates. Film thickness varied from two to three dozens of unit cells. Bi{sub 3}Fe{sub 5}O{sub 12} films grow pseudomorphically on substrates up to a thickness of 20 nm, and then a lattice relaxation occurs. Magnetic properties of the films were studied as a function of bismuth iron garnet thickness. The magnetization and cubic anisotropy decrease with decreasing film thickness. The uniaxial magnetocrystalline anisotropy is constant for all film thicknesses. For two unit cell thick films, the easy magnetization axis changes from in-plane to perpendicular to the plane direction. Such a reorientation takes place as a result of the competition of constant uniaxial perpendicular anisotropy with weakening film magnetization. - Highlights: ► Ultrathin Bi{sub 3}Fe{sub 5}O{sub 12} films were grown epitaxially on structure-matching substrates. ► Magnetic properties of Bi{sub 3}Fe{sub 5}O{sub 12} were studied down to the thickness of 2.5 nm. ► Reorientation of easy magnetization axis as a function of film thickness was observed.

  9. New Bismuth-Substituted Hydroxyapatite Nanoparticles for Bone Tissue Engineering

    Science.gov (United States)

    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.

  10. Preparation and characterization of nanocrystalline powders of bismuth vanadate

    Energy Technology Data Exchange (ETDEWEB)

    Shantha, K.; Varma, K.B.R. [Indian Inst. of Science, Bangalore (India). Materials Research Centre

    1999-05-31

    The influence of mechanical activation on the formation of Bi{sub 2}VO{sub 5.5}, bismuth vanadate (BiV) phase, was investigated by ball-milling a stoichiometric mixture of bismuth oxide and vanadium pentoxide. The structural evolution of the desired BiV phase, via an intermediate BiVO{sub 4} phase, was investigated using X-ray powder diffraction (XRD), differential thermal analysis (DTA) and transmission electron microscopy (TEM). Milling for 54h yielded monophasic {gamma}-BiV powders with an average crystallite size of 30 nm. The electron paramagnetic resonance (EPR) peaks associated with the V{sup 4+} ions are stronger and broader in nanocrystalline (n) BiV than in the conventionally prepared microcrystalline (m) BiV, suggesting that a significant portion of V{sup 5+} has been transformed to V{sup 4+} during milling. The optical bandgap of n-BiV was found to be higher than that of m-BiV. High density (97% of the theoretical density), fine-grained (average grain-size of 2 {mu}m) ceramics with uniform grain-size distribution could be fabricated using n-BiV powders. These fine-grained ceramics exhibit improved dielectric, pyro and ferroelectric properties. (orig.) 29 refs.

  11. Superconductivity in Bismuth. A New Look at an Old Problem

    Science.gov (United States)

    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

  12. Synthesis and characterization of bismuth alkaline titanate powders

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Huerta, A.M., E-mail: atorresh@ipn.mx [CICATA-Altamira, Instituto Politecnico Nacional, Km. 14.5 Carretera Tampico Puerto Industrial Altamira, Altamira, Tamps. 89600 (Mexico); Dominguez-Crespo, M.A. [CICATA-Altamira, Instituto Politecnico Nacional, Km. 14.5 Carretera Tampico Puerto Industrial Altamira, Altamira, Tamps. 89600 (Mexico); Hernandez-Perez, M.A. [ESIQIE, Metalurgia, Instituto Politecnico Nacional, Mexico, D. F (Mexico); Garcia-Zaleta, D.S. [CICATA-Altamira, Instituto Politecnico Nacional, Km. 14.5 Carretera Tampico Puerto Industrial Altamira, Altamira, Tamps. 89600 (Mexico); Brachetti-Sibaja, S.B. [CICATA-Altamira, Instituto Politecnico Nacional, Km. 14.5 Carretera Tampico Puerto Industrial Altamira, Altamira, Tamps. 89600 (Mexico); Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo esq. Sor Juana Ines de la Cruz s/n Col. Los Mangos C.P.89440 Cd. Madero Tamaulipas (Mexico)

    2011-06-15

    In this work, samples of bismuth alkaline titanate, (K{sub 0.5}Na{sub 0.5}){sub (2-x/2)}Bi{sub (x/6)}TiO{sub 3}, (x = 0.05-0.75) have been prepared by conventional ceramic technique and molten salts. Metal oxides or carbonates powders were used as starting raw materials. The crystalline phase of the synthesized powders was identified by the X-ray diffraction (XRD) and particle morphology was characterized by scanning electron microscopy (SEM). Solid state reaction method was unsuccessful to obtain pellets. From XRD results, a rhombohedral structure was detected and the parameter lattice were estimated to be a = 5.5478 A and {alpha} = 59.48{sup o}. These parameters were used to refine the structure by Rietveld analysis. SEM results showed several morphologies. Apparently, bismuth is promoting the grain growth whose sizes vary from 30 nm to 180 nm It is expected that these materials can be utilized in practical applications as substitutes for lead zirconatetitanate (PZT)-based ceramics.

  13. Genotoxic effects of bismuth (III oxide nanoparticles by comet assay

    Directory of Open Access Journals (Sweden)

    Reecep Liman

    2015-06-01

    Full Text Available Bismuth oxide is one of the important transition metal oxides and it has been intensively studied due to their peculiar characteristics (semiconductor band gap, high refractive index, high dielectric permittivity, high oxygen conductivity, resistivity, photoconductivity and photoluminescence etc.. Therefore, it is used such as microelectronics, sensor technology, optical coatings, transparent ceramic glass manufacturing, nanoenergetic gas generator, biosensor for DNA hybridization, potential immobilizing platforms for glucose oxidase and polyphenol oxidase, fuel cells, a additive in paints, an astringent in a variety of medical creams and topical ointments, and for the determination of heavy metal ions in drinking water, mineral water and urine. In addition this, Bismuth (III oxide nanoparticles (BONPs are favorable for the biomolecules adsorption than regular sized particles because of their greater advantages and novel characteristics (much higher specific surface, greater surface free energy, and good electrochemical stability etc.. Genotoxic effects of BONPs were investigated on the root cells of Allium cepa by Comet assay. A. cepa roots were treated with the aqueous dispersions of BONPs at 5 different concentrations (12.5, 25, 50, 75, and 100 ppm for 4 h. A significant increase in DNA damage was also observed at all concentrations of BONPs except 12.5 ppm by Comet assay. The results were also analyzed statistically by using SPSS for Windows; Duncan’s multiple range test was performed. These result indicate that BONPs exhibit genotoxic activity in A. cepa root meristematic cells.

  14. Nonproportionality in the scintillation light yield of bismuth germanate

    CERN Document Server

    Gentile, T R; Breuer, H; Chupp, T E; Coakley, K J; Cooper, R L; Nico, J S; O'Neill, B

    2015-01-01

    We present measurements of nonproportionality in the scintillation light yield of bismuth germanate (BGO) for gamma-rays with energies between 6 keV and 662 keV. The scintillation light was read out by avalanche photodiodes (APDs) with both the BGO crystals and APDs operated at a temperature of approximately 90 K. Data were obtained using radioisotope sources to illuminate both a single BGO crystal in a small test cryostat and a 12-element detector in a neutron radiative beta-decay experiment. In addition one datum was obtained in a 4.6 T magnetic field based on the bismuth K x-ray escape peak produced by a continuum of background gamma rays in this apparatus. These measurements and comparison to prior results were motivated by an experiment to study the radiative decay mode of the free neutron. The combination of data taken under different conditions yields a reasonably consistent picture for BGO nonproportionality that should be useful for researchers employing BGO detectors at low gamma ray energies.

  15. Phase transition of solid bismuth under high pressure

    Science.gov (United States)

    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).

  16. Geology of the florencia gold – telluride deposit (camagüey, cuba) and some metallurgical considerations

    OpenAIRE

    López K Jesús M.; Moreira Jesús; Gandarillas José

    2011-01-01

    This paper describes the results from a study of the Florencia gold-telluride deposit in Central Cuba, including mineralogical, petrographical, microprobe and chemical analysis. Valuable information is provided for the exploration, mining and processing of gold ores from other nearby deposits with similar characteristics. Results highlight changes in the mineralogical composition of the ores between the north and south sectors of the deposit, as reflected in metallurgical concentrates after b...

  17. Solar Water Splitting and Nitrogen Fixation with Layered Bismuth Oxyhalides.

    Science.gov (United States)

    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

  18. Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose new designs of plasmonic modulators, which can beused for dynamic signal switching in photonic integrated circuits. We studyperformance of a plasmonic waveguide modulator with bismuth ferrite as atunable material. The bismuth ferrite core is sandwiched between metalplates (metal...... modulation in both phase andamplitude control schemes. Due to high field confinement between themetal layers, existence of mode cut-offs for certain values of the corethickness, and near-zero material losses in bismuth ferrite, efficientmodulation performance is achieved. For the phase control scheme...

  19. Is the ultra-fast transformation of bismuth non-thermal?

    CERN Document Server

    Gamaly, E G

    2009-01-01

    Transient state of femtosecond laser excited bismuth has been studied by various groups with time-resolved optical, x-ray, and electron probes at the deposited energy density from below through up to several times the equilibrium enthalpy of melting. However, the interpretations of the experimental results are controversial: the optical probes reveal the absence of transition to the melting phase while the authors of x-ray and electron diffraction experiments claim the observation of ultrafast non-thermal melting. The presented analysis, based on temperature dependence of bismuth optical properties, unequivocally shows a purely thermal nature of all the observed fs-laser induced transformations in bismuth.

  20. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE)

    Science.gov (United States)

    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

  1. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE

    Directory of Open Access Journals (Sweden)

    Carlo Dossi

    2016-07-01

    Full Text Available 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.

  2. High-Rate Vapor Deposition of Cadmium Telluride Films for Solar Cells

    Science.gov (United States)

    Khan, Nasim Akhter

    1992-01-01

    High rate vapor deposition is presently used for large scale low cost deposition of thin films for packaging and other applications. The feasibility of using this technology for low cost deposition of solar cells was explored. After an exhaustive literature survey, the cadmium telluride (CdTe) solar cell was found to be most suitable candidate for high rate vapor deposition. The high rate vapor deposition was investigated by sublimation with a short distance between sublimation source and the substrate (Close-Spaced Sublimation, CSS). Cadmium telluride (CdTe) solar cells were fabricated by depositing CdTe films at different rates on cadmium sulphide (CdS) films deposited by CSS or by evaporation. The CdTe films deposited at higher deposition rates were observed to have open circuit voltages (V_{ rm oc}) comparable to those deposited at lower rates. The effect of CdS film which acts as window layer for the cells were also investigated on the V_ {rm oc} of the solar cells. The results achieved proved the fact that CdS window layer is necessary to achieve higher V_{ rm oc} from solar cells. The substrate temperature during deposition of films by close space sublimation plays a vital role in the performance of solar cell. The increase in the substrate temperature during deposition of CdTe films increased the V_{rm oc} of solar cells. The solar cells with indium tin oxide (ITO) as top conductor, i.e. ITO/CdS/CdTe configuration were fabricated at rates up to 34 mum/minute and with tin oxide (TO) i.e. TO/CdTe configuration fabricated at rates up to 79 mum/minute have shown similar V_{rm oc} compared to those produced at lower rates. Higher CdTe film deposition rates are possible with larger capacity experimental setup. The method of contacting CdTe, used in this study, results in higher series resistance. An improved method of contacting CdTe needs to be developed.

  3. In situ formation of bismuth nanoparticles through electron-beam irradiation in a transmission electron microscope

    Science.gov (United States)

    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.

  4. In situ formation of bismuth nanoparticles through electron-beam irradiation in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda-Guzman, S; Elizondo-Villarreal, N; Ferrer, D; Torres-Castro, A; Gao, X; Zhou, J P; Jose-Yacaman, M [Chemical Engineering Department and Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States)

    2007-08-22

    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.

  5. Potentiation of the action of metronidazole on Helicobacter pylori by omeprazole and bismuth subcitrate

    DEFF Research Database (Denmark)

    Andersen, L P; Colding, H; Kristiansen, J E

    2000-01-01

    Treatment failures using triple therapy that include metronidazole, are common in patients infected with metronidazole-resistant Helicobacter pylori in the gastric mucosa. Higher eradication rates in such patients have been described when treatment regimens include bismuth salts compared...

  6. Three-component synthesis of amidoalkyl naphthols catalyzed by bismuth(Ⅲ) nitrate pentahydrate

    Institute of Scientific and Technical Information of China (English)

    Min Wang; Yan Liang; Ting Ting Zhang; Jing Jing Gao

    2012-01-01

    Bismuth(Ⅲ) nitrate pentahydrate catalyzed the three-component condensation of β-naphthol,aldehydes and amines/urea under solvent-free conditions to afford the corresponding amidoalkyl naphthols in excellent yields.

  7. Corrosion by liquid lead and lead-bismuth: experimental results review and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinsuo [Los Alamos National Laboratory

    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.

  8. Effects of bismuth vandate and anthraquinone dye on the photodegradation of polycarbonate

    OpenAIRE

    Saron,Clodoaldo; Felisberti, Maria Isabel; Zulli, Fabio; Giordano, Marco

    2007-01-01

    Both inorganic and organic compounds, such as oxides or salts of metals and polycyclic and azo compounds, are frequently used as colorants in polymeric systems. Bismuth vanadate pigment has been used as an environmentally friendly alternative for cadmium containing pigments and anthraquinone dyes represent a polycyclic colorant class of wide use in polymers. Besides their coloring properties, both bismuth vanadate and anthraquinone present photocatalytic activity or photochemical properties t...

  9. Reactive magnetron sputtering deposition of bismuth tungstate onto titania nanoparticles for enhancing visible light photocatalytic activity

    Science.gov (United States)

    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.

  10. Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator

    OpenAIRE

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose new designs of plasmonic modulators, which can be utilized for dynamic signal switching in photonic integrated circuits. We study performance of plasmonic waveguide modulator with bismuth ferrite as an active material. The bismuth ferrite core is sandwiched between metal plates (metal-insulator-metal configuration), which also serve as electrodes so that the core changes its refractive index under applied voltage by means of partial in-plane to out-of-plane reorientation of ferroel...

  11. Multi-stage uplift of the Rocky Mountains: new age constraints on the Telluride Conglomerate and regional compilation of apatite fission track ages

    Science.gov (United States)

    Donahue, M. S.; Karlstrom, K. E.; Gonzales, D. A.; Pecha, M.; McKeon, R. E.

    2011-12-01

    The Telluride Conglomerate, exposed on the western flanks of Oligocene caldera complexes of the San Juan Mountains of Colorado, has historically been considered an Eocene alluvial deposit overlying the "Rocky Mountain erosion surface" and pre-dating Oligocene volcanism. Measured sections show that the Telluride preserves an unroofing sequence with basal units dominated by Paleozoic sedimentary clasts transitioning into upper units dominated by locally derived Proterozoic basement mixed with previously unrecognized andesitic Oligocene volcanics. Paleoflow directions and thicknesses of the preserved unit indicate the Telluride Conglomerate was deposited by a large, high-energy WNW- flowing braided river system. Detrital zircon analysis indicates minimum ages for individual grains within the Telluride Conglomerate of 28.0 to 31.5 Ma. This, plus the entrained volcanic clasts, redefines the unit as being of Oligocene age and indicates that conglomeratic deposition overlapped with regional San Juan volcanism and just predated major caldera eruptions at 28.4 Ma (San Juan and Uncompahgre) and 27.6 Ma (Silverton). We interpret the deposition of the Telluride Conglomerate to be the depositional response to regional uplift and erosion related to early stages of San Juan magmatism. These units have undergone significant post-depositional tectonism: the Telluride Conglomerate is found at ~9,000ft elevation near Telluride, CO, but is at ~13,000' at its westernmost exposure at Mt. Wilson. We attribute this differential uplift to be associated with faulting, pluton emplacement, and additional mantle driven uplift associated with the emplacement and cooling of the Wilson Stock in the last 20-22 Ma as documented by Miocene cooling seen in apatite helium (AHe) ages. This cooling fits into our regional compilation of published apatite fission track (AFT) and AHe data showing temporally and spatially partitioned Cenozoic cooling indicative of multistage uplift of the Rocky Mountain

  12. Exhaustive removal of chloride ions from water with the aid of a bismuth-based metallic sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Moskvin, L.N.; Ushenko, V.G.

    1988-04-20

    The authors discuss the sorption properties of sorbents based on metallic bismuth, in relation to a solution of the problem of exhaustive removal of chloride ions from water. Metallic sorbents with bismuth contents of 10 mass % on polytetrafluoroethylene were used. The sorption properties of sorbents based on metallic bismuth and on Bi/sub 2/O/sub 3/ were studied under dynamic conditions. Their results show that bismuth-based metal sorbents and sorbents based on bismuth oxide can be used as inorganic anion-exchangers. In order to demonstrate the possibility of selective separation of chloride ions from solutions they determined the dynamic exchange capacity for chloride ions at various nitrate-ion concentrations. The use of the proposed sorbents based on metallic bismuth for exhaustive purification of water lowers the chloride-ion concentration in the water sharply in comparison with the level achieved by ion-exchange purification with the aid of organic anion-exchangers.

  13. Fabrication and characterization of grain-oriented bismuth vanadate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shantha, K.; Varma, K.B.R. [Indian Inst. of Science, Bangalore (India). Materials Research Centre

    1997-11-01

    Grain-oriented (GO; 79%), high density (96% of the theoretical value) ceramics of bismuth vanadate, Bi{sub 2}VO{sub 5.5}, have been fabricated via a liquid-phase-aided two-stage sintering process. Scanning electron microscopy (SEM) was employed to monitor the crystallite size and the morphology of the starting powders and the microstructure of the sintered ceramics. X-ray diffraction (XRD) studies were carried out to verify the grain-orientation in the ceramics. The dielectric constant and the conductivity studies carried out along the directions perpendicular and parallel to the pressing axis show significant anisotropies (1.7 and 5.3, respectively, at 300 K). The grain-oriented ceramics were found to exhibit improved ferroelectric properties, with higher remnant polarization (P{sub r}) and lower coercive field (E{sub c}) than those of the randomly oriented (RO) ceramics.

  14. High ionic conductivity in confined bismuth oxide-based heterostructures

    Science.gov (United States)

    Sanna, Simone; Esposito, Vincenzo; Christensen, Mogens; Pryds, Nini

    2016-12-01

    Bismuth trioxide in the cubic fluorite phase (δ -Bi2O3 ) exhibits the highest oxygen ionic conductivity. In this study, we were able to stabilize the pure δ -Bi2O3 at low temperature with no addition of stabilizer but only by engineering the interface, using highly coherent heterostructures made of alternative layers of δ -Bi2O3 and Yttria Stabilized Zirconia (YSZ), deposited by pulsed laser deposition. The resulting [δ -Bi2O3 /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 -Bi2O3 , which is approximately two orders of magnitude higher than the conductivity of YSZ bulk.

  15. Structural investigation of Zn doped sodium bismuth borate glasses

    Science.gov (United States)

    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.

  16. High thermoelectric performance of the distorted bismuth(110) layer.

    Science.gov (United States)

    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.

  17. Compatibility of structural materials with liquid bismuth, lead, and mercury

    Energy Technology Data Exchange (ETDEWEB)

    Weeks, J.R. [Brookhaven National Lab., Upton, NY (United States)

    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.

  18. Spark plasma sintering of hydrothermally synthesized bismuth ferrite

    Directory of Open Access Journals (Sweden)

    Zorica Branković

    2016-12-01

    Full Text Available Bismuth ferrite, BiFeO3 (BFO, powder was synthesized by hydrothermal method from Bi(NO33·5 H2O and Fe(NO33·9 H2O as precursors. The synthesized powder was further sintered using spark plasma sintering (SPS. The sintering conditions were optimized in order to achieve high density, minimal amount of secondary phases and improved ferroelectric and magnetic properties. The optimal structure and properties were achieved after spark plasma sintering at 630 °C for 20 min, under uniaxial pressure of 90 MPa. The composition, microstructure, ferroelectric and magnetic properties of the SPS samples were characterized and compared to those of conventionally sintered ceramics obtained from the same powder. Although the samples sintered using conventional method showed slightly lower amount of secondary phases, the spark plasma sintered samples exhibited favourable microstructure and better ferroelectric properties.

  19. High ionic conductivity in confined bismuth oxide-based heterostructures

    Directory of Open Access Journals (Sweden)

    Simone Sanna

    2016-12-01

    Full Text Available Bismuth trioxide in the cubic fluorite phase (δ-Bi2O3 exhibits the highest oxygen ionic conductivity. In this study, we were able to stabilize the pure δ-Bi2O3 at low temperature with no addition of stabilizer but only by engineering the interface, using highly coherent heterostructures made of alternative layers of δ-Bi2O3 and Yttria Stabilized Zirconia (YSZ, deposited by pulsed laser deposition. The resulting [δ-Bi2O3/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-Bi2O3, which is approximately two orders of magnitude higher than the conductivity of YSZ bulk.

  20. Formic Acid Oxidation at Platinum-Bismuth Clusters

    DEFF Research Database (Denmark)

    Lovic, J. D.; Stevanovic, S. I.; Tripkovic, D. V.

    2014-01-01

    Formic acid oxidation was studied on platinum-bismuth deposits on glassy carbon (GC) substrate. The catalysts of equimolar ratio were prepared by potentiostatic deposition using chronocoulometry. Bimetallic structures obtained by two-step process, comprising deposition of Bi followed by deposition...... of Pt, were characterized by AFM spectroscopy which indicated that Pt crystallizes preferentially onto previously formed Bi particles. The issue of Bi leaching (dissolution) from PtBi catalysts, and their catalytic effect alongside the HCOOH oxidation is rather unresolved. In order to control Bi...... dissolution, deposits were subjected to electrochemical oxidation, in the relevant potential range and supporting electrolyte, prior to use as catalysts for HCOOH oxidation. Anodic striping charges indicated that along oxidation procedure most of deposited Bi was oxidized. ICP mass spectroscopy analysis...

  1. Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Klaus Reichmann

    2015-12-01

    Full Text Available The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.

  2. A novel synthesis of perovskite bismuth ferrite nanoparticles

    Directory of Open Access Journals (Sweden)

    Alexandre Z. Simões

    2011-09-01

    Full Text Available Microwave assisted hydrothermal (MAH method was used to synthesize crystalline bismuth ferrite (BiFeO3 nanoparticles (BFO at temperature of 180°C with times ranging from 5 min to 1 h. For comparison, BFO powders were also crystallized by the soft chemistry route in a conventional furnace at a temperature of 850°C for 4 h. X-ray diffraction (XRD results verified the formation of perovskite BFO crystallites while infrared data showed no traces of carbonate. Field emission scanning microcopy (FE/SEM revealed a homogeneous size distribution of nanometric BFO powders. MAH method produced nanoparticles of 96% pure perovskite, with a size of 130 nm. These results are in agreement with Raman scattering values which show that the MAH synthesis route is rapid and cost effective. This method could be used as an alternative to other chemical methods in order to obtain BFO nanoparticles.

  3. Bismuth coatings deposited by the pulsed dc sputtering technique

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M. F.; Olaya, J. J.; Alfonso, J. E., E-mail: jealfonsoo@unal.edu.co [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia de Materiales y Superficies, Carrera 45 No. 26-85, Edif. Uriel Gutierrez, Bogota D. C. (Colombia)

    2013-08-01

    In this work we present the results obtained from the deposition of nano-structured bismuth coatings through Dc pulsed unbalanced magnetron sputtering. The coatings were grown on two substrates: silicon and AISI steel 316 L. The microstructure of the Bi coatings grown on silicon and the corrosion resistance of the Bi coatings grown on AISI steel were evaluated. The microstructure was evaluated by X-ray diffraction and the corrosion resistance was characterized by means of polarization potentiodynamic and electrochemical impedance spectroscopy. Finally the morphology of the coatings was evaluated through scanning electronic microscopy. The X-ray diffraction analysis indicates that the coatings are polycrystalline; the corrosion resistance tests indicate that the films with better corrosion resistance were deposited at 40 khz. Scanning electron microscopy micrographs show that the coatings are grown as granular form. (Author)

  4. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

  5. Adverse events with bismuth salts for Helicobacter pylori eradication:Systematic review and meta-analysis

    Institute of Scientific and Technical Information of China (English)

    Alexander C Ford; Peter Malfertheiner; Monique Giguére; José Santana; Mostafizur Khan; Paul Moayyedi

    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.

  6. Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm

    Science.gov (United States)

    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. Wine as a digestive aid: comparative antimicrobial effects of bismuth salicylate and red and white wine.

    Science.gov (United States)

    Weisse, M. E.; Eberly, B.; Person, D. A.

    1995-01-01

    OBJECTIVE--To test whether red and white wines are as potent as bismuth salicylate against the bacteria responsible for traveller's diarrhoea to try to explain wine's legendary reputation as a digestive aid. DESIGN--Red and white wine, bismuth salicylate, two solutions containing ethanol (diluted absolute ethanol and tequila), and sterilised water were tested against suspensions of salmonella, shigella, and Escherichia coli to determine relative antibacterial activity. Suspensions of 10(7) colony forming units of shigella, salmonella, and E coli were added to the test solutions and plated on standard nutrient agar at 0, 10, 20, 30, 60, and 120 minutes and 24 hours. Dilutions of wine and bismuth salicylate were then tested with E coli as the test bacterium, and the experiment repeated. MAIN OUTCOME MEASURES--Exposure times necessary for eradication of organisms for the different solutions; decreases in colony counts at the different exposure times for dilutions of wine and bismuth salicylates. RESULTS--Undiluted wine and bismuth salicylate were both effective in reducing the number of viable organisms (by 10(5)-10(6) colony forming units) after 20-30 minutes. Dilutions of wine were much more effective in decreasing colony counts than were similar dilutions of bismuth salicylate. CONCLUSION--The antibacterial property of wine is largely responsible for wine's reputation as a digestive aid. Images p1659-a PMID:8541747

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

    Science.gov (United States)

    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.

  9. Polonium problem in lead-bismuth flow target

    Energy Technology Data Exchange (ETDEWEB)

    Pankratov, D.V.; Yefimov, E.I.; Bugreev, M.I. [State Scientific Centre of Russian Federation-Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    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. Directional Solidification of Mercury Cadmium Telluride During the Second United States Microgravity Payload Mission (USMP-2)

    Science.gov (United States)

    Gillies, D. C.; Lehoczky, S. L.; Szofran, F. R.; Watring, D. A.; Alexander, H. A.; Jerman, G. A.

    1996-01-01

    As a solid solution semiconductor having, a large separation between liquidus and solidus, mercury cadmium telluride (MCT) presents a formidable challenge to crystal growers desiring an alloy of high compositional uniformity. To avoid constitutional supercooling during Bridgman crystal growth it is necessary to solidify slowly in a high temperature gradient region. The necessary translation rate of less than 1 mm/hr results in a situation where fluid flow induced by gravity on earth is a significant factor in material transport. The Advanced Automated Directional Solidification Furnace (AADSF) is equipped to provide the stable thermal environment with a high gradient, and the required slow translation rate needed. Ground based experiments in AADSF show clearly the dominance of flow driven transport. The first flight of AADSF in low gravity on USMP-2 provided an opportunity to test theories of fluid flow in MCT and showed several solidification regimes which are very different from those observed on earth. Residual acceleration vectors in the orbiter during the mission were measured by the Orbital Acceleration Research Experiment (OARE), and correlated well with observed compositional differences in the samples.

  11. Resonant Enhancement of Charge Density Wave Diffraction in the Rare-Earth Tri-Tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.S.; Sorini, A.P.; Yi, M.; Chuang, Y.D.; Moritz, B.; Yang, W.L.; Chu, J.-H.; Kuo, H.H.; Gonzalez, A.G.Cruz; Fisher, I.R.; Hussain, Z.; Devereau, T.P.; Shen, Z.X.

    2012-05-15

    We performed resonant soft X-ray diffraction on known charge density wave (CDW) compounds, rare earth tri-tellurides. Near the M{sub 5} (3d - 4f) absorption edge of rare earth ions, an intense diffraction peak is detected at a wavevector identical to that of CDW state hosted on Te{sub 2} planes, indicating a CDW-induced modulation on the rare earth ions. Surprisingly, the temperature dependence of the diffraction peak intensity demonstrates an exponential increase at low temperatures, vastly different than that of the CDW order parameter. Assuming 4f multiplet splitting due to the CDW states, we present a model to calculate X-ray absorption spectrum and resonant profile of the diffraction peak, agreeing well with experimental observations. Our results demonstrate a situation where the temperature dependence of resonant X-ray diffraction peak intensity is not directly related to the intrinsic behavior of the order parameter associated with the electronic order, but is dominated by the thermal occupancy of the valence states.

  12. Heart imaging by cadmium telluride gamma camera European Program 'BIOMED' consortium

    CERN Document Server

    Scheiber, C; Chambron, J; Prat, V; Kazandjan, A; Jahnke, A; Matz, R; Thomas, S; Warren, S; Hage-Hali, M; Regal, R; Siffert, P; Karman, M

    1999-01-01

    Cadmium telluride semiconductor detectors (CdTe) operating at room temperature are attractive for medical imaging because of their good energy resolution providing excellent spatial and contrast resolution. The compactness of the detection system allows the building of small light camera heads which can be used for bedside imaging. A mobile pixellated gamma camera based on 2304 CdTe (pixel size: 3x3 mm, field of view: 15 cmx15 cm) has been designed for cardiac imaging. A dedicated 16-channel integrated circuit has also been designed. The acquisition hardware is fully programmable (DSP card, personal computer-based system). Analytical calculations have shown that a commercial parallel hole collimator will fit the efficiency/resolution requirements for cardiac applications. Monte-Carlo simulations predict that the Moire effect can be reduced by a 15 deg. tilt of the collimator with respect to the detector grid. A 16x16 CdTe module has been built for the preliminary physical tests. The energy resolution was 6.16...

  13. Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism

    Science.gov (United States)

    Yan, Si-Qi; Xing, Rui; Zhou, Yan-Feng; Li, Kai-Le; Su, Yuan-Yuan; Qiu, Jian-Feng; Zhang, Yun-Hu; Zhang, Ke-Qin; He, Yao; Lu, Xiao-Ping; Xu, Shi-Qing

    2016-09-01

    Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32 nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations.

  14. Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae.

    Science.gov (United States)

    Fan, Junpeng; Shao, Ming; Lai, Lu; Liu, Yi; Xie, Zhixiong

    2016-01-01

    Cadmium telluride quantum dots (CdTe QDs) are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe) QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L) were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L) to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator), combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells.

  15. Two-color detector: Mercury-cadmium-telluride as a terahertz and infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Sizov, F.; Zabudsky, V.; Petryakov, V.; Golenkov, A.; Andreyeva, K.; Tsybrii, Z. [Institute of Semiconductor Physics, 03028 Kiev (Ukraine); Dvoretskii, S. [Institute of Semiconductor Physics of SB RAS, 630090 Novosibirsk (Russian Federation)

    2015-02-23

    In this paper, issues associated with the development of infrared (IR) and terahertz (THz) radiation detectors based on HgCdTe are discussed. Two-color un-cooled and cooled to 78 K narrow-gap mercury-cadmium-telluride semiconductor thin layers with antennas were considered both as sub-THz (sub-THz) direct detection bolometers and 3–10 μm IR photoconductors. The noise equivalent power (NEP) for one of the detectors studied at ν ≈ 140 GHz reaches NEP{sub 300 K} ≈ 4.5 × 10{sup −10} W/Hz{sup 1/2} and NEP{sub 78 K} ≈ 5 × 10{sup −9} W/Hz{sup 1/2}. The same detector used as an IR photoconductor showed the responsivity at temperatures T = 78 K and 300 K with signal-to-noise ratio S/N ≈ 750 and 50, respectively, under illumination by using IR monochromator and globar as a thermal source.

  16. Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

    Energy Technology Data Exchange (ETDEWEB)

    B. A. Brunett; J. C. Lund; J. M. Van Scyoc; N. R. Hilton; E. Y. Lee; R. B. James

    1999-01-01

    The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors.

  17. Influence of the Ion Coordination Number on Cation Exchange Reactions with Copper Telluride Nanocrystals

    CERN Document Server

    Tu, Renyong; Bertoni, Giovanni; Lak, Aidin; Gaspari, Roberto; Rapallo, Arnaldo; Cavalli, Andrea; De Trizio, Luca; Manna, Liberato

    2016-01-01

    Cu2-xTe nanocubes were used as starting seeds to access metal telluride nanocrystals by cation exchanges at room temperature. The coordination number of the entering cations was found to play an important role in dictating the reaction pathways. The exchanges with tetrahedrally coordinated cations (i.e. with coordination number 4), such as Cd2+ or Hg2+, yielded monocrystalline CdTe or HgTe nanocrystals with Cu2-xTe/CdTe or Cu2-xTe/HgTe Janus-like heterostructures as intermediates. The formation of Janus-like architectures was attributed to the high diffusion rate of the relatively small tetrahedrally coordinated cations, which could rapidly diffuse in the Cu2-xTe NCs and nucleate the CdTe (or HgTe) phase in a preferred region of the host structure. Also, with both Cd2+ and Hg2+ ions the exchange led to wurtzite CdTe and HgTe phases rather than the more stable zinc-blende ones, indicating that the anion framework of the starting Cu2- xTe particles could be more easily deformed to match the anion framework of t...

  18. Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Patrick R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2010-01-07

    Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

  19. LEACHING OF CADMIUM, TELLURIUM AND COPPER FROM CADMIUM TELLURIDE PHOTOVOLTAIC MODULES.

    Energy Technology Data Exchange (ETDEWEB)

    FTHENAKIS,V.

    2004-02-03

    Separating the metals from the glass is the first step in recycling end-of-life cadmium telluride photovoltaic modules and manufacturing scrap. We accomplished this by leaching the metals in solutions of various concentrations of acids and hydrogen peroxide. A relatively dilute solution of sulfuric acid and hydrogen peroxide was found to be most effective for leaching cadmium and tellurium from broken pieces of CdTe PV modules. A solution comprising 5 mL of hydrogen peroxide per kg of PV scrap in 1 M sulfuric acid, gave better results than the 12 mL H{sub 2}O{sub 2}/kg, 3.2 M H{sub 2}SO{sub 4} solution currently used in the industry. Our study also showed that this dilute solution is more effective than hydrochloric-acid solutions and it can be reused after adding a small amount of hydrogen peroxide. These findings, when implemented in large-scale operation, would result in significant savings due to reductions in volume of the concentrated leaching agents (H{sub 2}SO{sub 4} and H{sub 2}O{sub 2}) and of the alkaline reagents required to neutralize the residuals of leaching.

  20. Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y; Levin, C S [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Matteson, J L; Skelton, R T; Deal, A C; Stephan, E A; Duttweiler, F; Gasaway, T M, E-mail: cslevin@stanford.edu [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States)

    2011-03-21

    This paper investigates the performance of 1 mm resolution cadmium zinc telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm x 40 mm x 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06 {+-} 0.39% at 511 keV throughout most of the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44 {+-} 0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78 {+-} 0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes-as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system.

  1. Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET

    Science.gov (United States)

    Gu, Y.; Matteson, J. L.; Skelton, R. T.; Deal, A. C.; Stephan, E. A.; Duttweiler, F.; Gasaway, T. M.; Levin, C. S.

    2011-03-01

    This paper investigates the performance of 1 mm resolution cadmium zinc telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06 ± 0.39% at 511 keV throughout most of the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44 ± 0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78 ± 0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes—as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system.

  2. Study of a high-resolution, 3-D positioning cadmium zinc telluride detector for PET

    Science.gov (United States)

    Gu, Y; Matteson, J L; Skelton, R T; Deal, A C; Stephan, E A; Duttweiler, F; Gasaway, T M; Levin, C S

    2011-01-01

    This paper investigates the performance of 1 mm resolution Cadmium Zinc Telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3-D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06±0.39% at 511 keV throughout most the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44±0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78±0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes – as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system. PMID:21335649

  3. Spectroscopic ellipsometry as a process control tool for manufacturing cadmium telluride thin film photovoltaic devices

    Science.gov (United States)

    Smith, Westcott P.

    In recent decades, there has been concern regarding the sustainability of fossil fuels. One of the more promising alternatives is Cadmium Telluride (CdTe) thin-film photovoltaic (PV) devices. Improved quality measurement techniques may aid in improving this existing technology. Spectroscopic ellipsometry (SE) is a common, non-destructive technique for measuring thin films in the silicon wafer industry. SE results have also been tied to properties believed to play a role in CdTe PV device efficiency. A study assessing the potential of SE for use as a quality measurement tool had not been previously reported. Samples of CdTe devices produced by both laboratory and industrial scale processes were measured by SE and Scanning Electron Microscopy (SEM). Mathematical models of the optical characteristics of the devices were developed and fit to SE data from multiple angles and locations on each sample. Basic statistical analysis was performed on results from the automated fits to provide an initial evaluation of SE as a quantitative quality measurement process. In all cases studied, automated SE models produced average stack thickness values within 10% of the values produced by SEM, and standard deviations for the top bulk layer thickness were less than 1% of the average values.

  4. The behaviour of Gd in lead and tin tellurides and its effect on their physical properties

    Science.gov (United States)

    Zayachuk, D. M.; Matulenis, E. L.; Mikityuk, V. I.

    1992-06-01

    The behaviour of gadolinium in Pb 1- xSn xTe (0 ⩽ x ⩽ 0.3) introduced during Bridgman growth and its effect on the composition profiles and free carrier concentration is investigated. The Gd, Pb, Sn and Te contents in crystals were determined by electron microprobe analysis, and the free carrier concentration was obtained by Hall measurements. The results indicate that Gd behaves like an impurity with a segregation coefficient larger than unity, which strongly depends on the Gd concentration N( L) Gd in the melt and is given by KS = 1 + Aexp( - BN( L) Gd), where A takes values of 8 or 9 and B a value of about 10 -20 cm 3. The effect of such a strong KS( N( L) Gd) dependence is that all the Gd impurity concentrates in the first-to-freeze section, leaving the rest of the ingot free from the impurity. Thus, by introducing Gd during melt growth of lead-tin telluride crystals, one can obtain high quality crystals of the solid solutions studied.

  5. Novel Cadmium Zinc Telluride Devices for Myocardial Perfusion Imaging-Technological Aspects and Clinical Applications.

    Science.gov (United States)

    Ben-Haim, Simona; Kennedy, John; Keidar, Zohar

    2016-07-01

    Myocardial perfusion imaging plays an important role in the assessment of patients with known or suspected coronary artery disease and is well established for diagnosis and for prognostic evaluation in these patients. The dedicated cardiac SPECT cameras with solid-state cadmium zinc telluride (CZT) detectors were first introduced a decade ago. A large body of evidence is building up, showing the superiority of the new technology compared with conventional gamma cameras. Not only the CZT detectors, but also new collimator geometries, the ability to perform focused imaging optimized for the heart and advances in data processing algorithms all contribute to the significantly improved sensitivity up to 8-10 times, as well as improved energy resolution and improved reconstructed spatial resolution compared with conventional technology. In this article, we provide an overview of the physical characteristics of the CZT cameras, as well as a review of the literature published so far, including validation studies in comparison with conventional myocardial perfusion imaging and with invasive coronary angiography, significant reduction in radiation dose, and new imaging protocols enabled by the new technology.

  6. Simulation study comparing high-purity germanium and cadmium zinc telluride detectors for breast imaging

    Science.gov (United States)

    Campbell, D. L.; Peterson, T. E.

    2014-11-01

    We conducted simulations to compare the potential imaging performance for breast cancer detection with High-Purity Germanium (HPGe) and Cadmium Zinc Telluride (CZT) systems with 1% and 3.8% energy resolution at 140 keV, respectively. Using the Monte Carlo N-Particle (MCNP5) simulation package, we modelled both 5 mm-thick CZT and 10 mm-thick HPGe detectors with the same parallel-hole collimator for the imaging of a breast/torso phantom. Simulated energy spectra were generated, and planar images were created for various energy windows around the 140 keV photopeak. Relative sensitivity and scatter and the torso fractions were calculated along with tumour contrast and signal-to-noise ratios (SNR). Simulations showed that utilizing a ±1.25% energy window with an HPGe system better suppressed torso background and small-angle scattered photons than a comparable CZT system using a -5%/+10% energy window. Both systems provided statistically similar contrast and SNR, with HPGe providing higher relative sensitivity. Lowering the counts of HPGe images to match CZT count density still yielded equivalent contrast between HPGe and CZT. Thus, an HPGe system may provide equivalent breast imaging capability at lower injected radioactivity levels when acquiring for equal imaging time.

  7. Semiconductor nanocrystals functionalized with antimony telluride zintl ions for nanostructured thermoelectrics.

    Science.gov (United States)

    Kovalenko, Maksym V; Spokoyny, Boris; Lee, Jong-Soo; Scheele, Marcus; Weber, Andrew; Perera, Susanthri; Landry, Daniel; Talapin, Dmitri V

    2010-05-19

    The energy efficiency of heat engines could be improved by the partial recovery of waste heat using thermoelectric (TE) generators. We show the possibility of designing nanostructured TE materials using colloidal inorganic nanocrystals functionalized with molecular antimony telluride complexes belonging to the family of Zintl ions. The unique advantage of using Zintl ions as the nanocrystal surface ligands is the possibility to convert them into crystalline metal chalcogenides, thus linking individual nanobuilding blocks into a macroscopic assembly of electronically coupled functional modules. This approach allows preserving the benefits of nanostructuring and quantum confinement while enabling facile charge transport through the interparticle boundaries. A developed methodology was applied for solution-based fabrication of nanostructured n- and p-type Bi(2-x)Sb(x)Te(3) alloys with tunable composition and PbTe-Sb(2)Te(3) nanocomposites with controlled grain size. Characterization of the TE properties of these materials showed that their Seebeck coefficients, electrical and thermal conductivities, and ZT values compared favorably with those of previously reported solution-processed TE materials.

  8. Macro-loading Effects in Inductively Coupled Plasma Etched Mercury Cadmium Telluride

    Science.gov (United States)

    Apte, Palash; Rybnicek, Kimon; Stoltz, Andrew

    2016-09-01

    This paper reports the effect of macro-loading on mercury cadmium telluride (Hg1- x Cd x Te) and Photoresist (PR) etched in an inductively coupled plasma (ICP). A significant macro-loading effect is observed, which affects the etch rates of both PR and Hg1- x Cd x Te. It is observed that the exposed silicon area has a significant effect on the PR etch rate, but not on the Hg1- x Cd x Te etch rate. It is also observed that the exposed Hg1- x Cd x Te area has a significant effect on the etch rate of the PR, but the exposed PR area does not seem to have an effect on the Hg1- x Cd x Te etch rate. Further, the exposed Hg1- x Cd x Te area is shown to affect the etch rate of the Hg1- x Cd x Te, but there does not seem to be a similar effect for the exposed PR area on the etch rate of the PR. Since the macro-loading affects the selectivity significantly, this effect can cause significant problems in the etching of deep trenches. A few techniques to reduce the effect of macro-loading on the etch rates of the PR and Hg1- x Cd x Te are listed, herein.

  9. Band gap engineering of zinc selenide thin films through alloying with cadmium telluride.

    Science.gov (United States)

    Al-Kuhaili, M F; Kayani, A; Durrani, S M A; Bakhtiari, I A; Haider, M B

    2013-06-12

    This work investigates band gap engineering of zinc selenide (ZnSe) thin films. This was achieved by mixing ZnSe with cadmium telluride (CdTe). The mass ratio (x) of CdTe in the starting material was varied in the range x = 0-0.333. The films were prepared using thermal evaporation. The chemical composition of the films was investigated through energy dispersive spectroscopy and Rutherford backscattering spectrometry. Structural analysis was carried out using X-ray diffraction and atomic force microscopy. Normal incidence transmittance and reflectance were measured over the wavelength range 300-1300 nm. The absorption coefficients and band gaps were determined from these spectrophotometric measurements. The band gap monotonically decreased from 2.58 eV (for x = 0) to 1.75 eV (for x = 0.333). Photocurrent measurements indicated that the maximum current density was obtained for films with x = 0.286. A figure of merit, based on crystallinity, band gap, and photocurrent, was defined. The optimum characteristics were obtained for the films with x = 0.231, for which the band gap was 2.14 eV.

  10. Properties of Te-rich cadmium telluride thin films fabricated by closed space sublimation technique

    Science.gov (United States)

    Abbas Shah, N.; Ali, A.; Ali, Z.; Maqsood, A.; Aqili, A. K. S.

    2005-11-01

    Cadmium telluride (CdTe) thin films were prepared by the closed space sublimation (CSS) technique, using CdTe powder as evaporant onto substrates of water-white glass. In the next step, the same procedure was adopted by using tellurium as evaporant and already deposited CdTe film as substrate. Such compositions were then annealed at 300 °C for 30 min to obtain Te-enriched films. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometry, DC electrical resistivity, dark conductivity and activation energy analysis as a function of temperature by two-probe method. The electron microprobe analyzer (EMPA) results showed an increase of Te content composition in the samples as the mass of the Te-deposition increased in CdTe. The Hall measurements indicated the increase in mobility and carrier concentrations of CdTe films by addition of tellurium. A significant change in the shape and size of the CdTe grains were observed.

  11. Investigations of Cadmium Manganese Telluride Crystals for Room-Temperature Radiation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.; Bolotnikov, A.; Camarda, G.; Cui, Y.; Hossain, A.; Kim, K.; Carcelen, V.; Gul, R.; James, R.

    2009-10-06

    Cadmium manganese telluride (CMT) has high potential as a material for room-temperature nuclear-radiation detectors. We investigated indium-doped CMT crystals taken from the stable growth region of the ingot, and compared its characteristics with that from the last-to-freeze region. We employed different techniques, including synchrotron white-beam X-ray topography (SWBXT), current-voltage (I-V) measurements, and low-temperature photoluminescence spectra, and we also assessed their responses as detectors to irradiation exposure. The crystal from the stable growth region proved superior to that from the last-to-freeze region; it is a single-grain crystal, free of twins, and displayed a resistivity higher by two orders-of-magnitude. The segregation of indium dopant in the ingot might be responsible for its better resistivity. Furthermore, we recorded a good response in the detector fabricated from the crystal taken from the stable growth region; its ({mu}{tau}){sub e} value was 2.6 x 10{sup -3} cm{sup 2}/V, which is acceptable for thin detectors, including for applications in medicine.

  12. Optical properties of cadmium telluride in zinc-blende and wurzite structure

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, S.M. [Department of Physics, Materials and Electroceramics Laboratory, Ferdowsi University of Mashhad (Iran, Islamic Republic of)], E-mail: sma_hosseini@yahoo.com

    2008-05-01

    The optical properties of cadmium telluride including the linear optical dielectric function, the refractive index, the extinction coefficient, the reflectivity and the plasmon energy have been calculated by density functional theory (DFT). The full potential linearized augmented plane wave (FL-LAPW) method was used with the generalized gradient approximation (GGA) including the orbital dependence of the self-energy, i.e. the orbital-dependent potentials of Coulomb and exchange interactions (GGA+U). Using only LDA or GGA methods underestimates the electronic parameters (band gap and band dispersion). Applying orbital-dependent potentials splits the Te-5s state and shifts the binding energies of the Cd-4d levels towards the experimentally determined position. The calculated results indicated that although Te-5s and Cd-4d overlap, Cd-4d plays an important role in absorption and reflectivity constants. The optical constants of CdTe in hexagonal structure exhibit anisotropy (birefringence) in two directions (in basal-plan and c-axis) but the difference is very small in the static limit.

  13. Optical properties of cadmium telluride in zinc-blende and wurzite structure

    Science.gov (United States)

    Hosseini, S. M.

    2008-05-01

    The optical properties of cadmium telluride including the linear optical dielectric function, the refractive index, the extinction coefficient, the reflectivity and the plasmon energy have been calculated by density functional theory (DFT). The full potential linearized augmented plane wave (FL-LAPW) method was used with the generalized gradient approximation (GGA) including the orbital dependence of the self-energy, i.e. the orbital-dependent potentials of Coulomb and exchange interactions (GGA+ U). Using only LDA or GGA methods underestimates the electronic parameters (band gap and band dispersion). Applying orbital-dependent potentials splits the Te-5s state and shifts the binding energies of the Cd-4d levels towards the experimentally determined position. The calculated results indicated that although Te-5s and Cd-4d overlap, Cd-4d plays an important role in absorption and reflectivity constants. The optical constants of CdTe in hexagonal structure exhibit anisotropy (birefringence) in two directions (in basal-plan and c-axis) but the difference is very small in the static limit.

  14. Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism

    Science.gov (United States)

    Yan, Si-Qi; Xing, Rui; Zhou, Yan-Feng; Li, Kai-Le; Su, Yuan-Yuan; Qiu, Jian-Feng; Zhang, Yun-Hu; Zhang, Ke-Qin; He, Yao; Lu, Xiao-Ping; Xu, Shi-Qing

    2016-01-01

    Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32 nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations. PMID:27669995

  15. 3D Particle Track Reconstrution in a Single Layer Cadmium-Telluride Hybrid Active Pixel Detector

    CERN Document Server

    Filipenko, Mykhaylo; Anton, Gisela; Michel, Thilo

    2014-01-01

    In the past 20 years the search for neutrinoless double beta decay has driven many developements in all kind of detector technology. A new branch in this field are highly-pixelated semiconductor detectors - such as the CdTe-Timepix detectors. It compromises a cadmium-telluride sensor of 14 mm x 14 mm x 1 mm size with an ASIC which has 256 x 256 pixel of 55 \\textmu m pixel pitch and can be used to obtain either spectroscopic or timing information in every pixel. In regular operation it can provide a 2D projection of particle trajectories; however, three dimensional trajectories are desirable for neutrinoless double beta decay and other applications. In this paper we present a method to obtain such trajectories. The method was developed and tested with simulations that assume some minor modifications to the Timepix ASIC. Also, we were able to test the method experimentally and in the best case achieved a position resolution of about 90 \\textmu m with electrons of 4.4 GeV.

  16. Spectral x-ray computed tomography scanner using a cadmium telluride detector

    Science.gov (United States)

    Sato, Eiichi; Oda, Yasuyuki; Yamaguchi, Satoshi; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Watanabe, Manabu; Kusachi, Shinya

    2016-10-01

    To obtain four tomograms with four different photon energy ranges simultaneously, we have developed a quad-energy Xray photon counter with a cadmium telluride (CdTe) detector and four sets of comparators and frequency-voltage converters (FVCs). X-ray photons are detected using the CdTe detector, and the event pulses from a shaping amplifier are sent to four comparators simultaneously to regulate four threshold energies of 20, 35, 50 and 65 keV. Using this counter, the energy ranges are 20-100, 35-100, 50-100 and 65-100 keV; the maximum energy corresponds to the tube voltage. Xray photons in the four ranges are counted using the comparators, and the logical pulses from the comparators are input to the FVCs. The outputs from the four FVCs are input to a personal computer through an analog-digital converter (ADC) to carry out quad-energy imaging. To observe contrast variations with changes in the threshold energy, we performed spectral computed tomography utilizing the quad-energy photon counter at a tube voltage of 100 kV and a current of 8.0 μA. In the spectral CT, four tomograms were obtained simultaneously with four energy ranges. The image contrast varied with changes in the threshold energy, and the exposure time for tomography was 9.8 min.

  17. Comparative study on solubilities of bismuth, bismuth oxide,and bismuth sulfide in hydrochloric acid-thiourea%铋、氧化铋、硫化铋在盐酸-硫脲中溶解性的比较研究

    Institute of Scientific and Technical Information of China (English)

    马哈亚·艾斯江; 巴哈尔古丽·别克吐尔逊

    2012-01-01

    在盐酸介质中及55℃加热条件下,铋与硫脲形成黄色络合物,从而建立了用分光光度法比较铋、氧化铋、硫化铋在盐酸-硫脲中溶解性的新方法.研究了反应介质、试剂浓度、加热时间、加热温度、震荡速率等因素的影响.在最佳实验条件下,溶液的质量浓度为0.04~0.24 mg/mL时符合比尔定律.相关系数R=0.999 9,检出限为1.05×10-2 μg/mL,标准偏差SD=0.003 5,相对标准偏差RSD=2.42%,摩尔吸收系数为1.515×105 L/(mol·cm),加标回收率为96.7%~98.8%.实验结果表明,铋、氧化铋、硫化铋的溶解性顺序大小为:铋>氧化铋>硫化铋.%A yellow complex is formed from bismuth and thiourea in hydrochloric acid under the heated condition of 55 °C. Thus a new method is set up to compare the solubilities of bismuth, bismuth oxide, and bismuth sulfide in hydrochloric acid-thiourea by using spectrophotometry.Effects of factors, such as reaction medium, reagent concentration, heating time, heating temperature, and oscillation speed,were studied respectively .Under the optimum experimental conditions, mass concentration of the solution is in line with Beer's law, when it is within the range of 0.04-0.24 mg/mL.The correlation coefficient (R) is 0.999 9.The detection limit is 1.05xl0-2μg/mL.The standard deviation is 0.003 5.The relative standard deviation (RSD) is 2.42%.The molar absorption coefficient is 1.515xl05 L/(mol-cm).The recovery rate of standard addition is at 96.7%~98.8%. Experimental result showed that the solubilities of bismuth,bismuth oxide,and bismuth sulfide in hydrochloric acid-thiourea is in order by size as following: Bi>Bi2O3>Bi2S3.

  18. Spectroscopic Characterization of Extracellular Polymeric Substances from Escherichia coli and Serratia marcescens: Suppression using Sub-Inhibitory Concentrations of Bismuth Thiols

    Energy Technology Data Exchange (ETDEWEB)

    Badireddy, Appala R.; Korpol, Bhoom Reddy; Chellam, Shankararaman; Gassman, Paul L.; Engelhard, Mark H.; Lea, Alan S.; Rosso, Kevin M.

    2008-10-21

    Free and capsular EPS produced by Escherichia coli and Serratia marcescens were characterized in detail using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES). Total EPS production decreased upon treatment with sub-inhibitory concentrations of lipophilic bismuth thiols (bismuth dimercaptopropanol, BisBAL; bismuth ethanedithiol, BisEDT; and bismuth pyrithione, BisPYR), BisBAL being most effective. Bismuth thiols also influenced acetylation and carboxylation of polysaccharides in EPS from S. marcescens. Extensive homology between EPS samples in the presence and absence of bismuth was observed with proteins, polysaccharides, and nucleic acids varying predominantly only in the total amount expressed. Second derivative analysis of the amide I region of FTIR spectra revealed decreases in protein secondary structures in the presence of bismuth thiols. Hence, anti-fouling properties of bismuth thiols appear to originate in their ability to suppress O-acetylation and protein secondary structures in addition to total EPS secretion.

  19. Spectroscopic properties of 2.7 μm emission in Er{sup 3+} doped telluride glasses and fibers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaokang [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Li, Kefeng, E-mail: kfli@siom.ac.cn [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Xia; Kuan, Peiwen; Wang, Xin [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Hu, Lili [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-12-05

    Highlights: • Telluride glasses with high Er{sup 3+} doping concentration and good thermal property are prepared. • Energy transfer processes for 1.5 μm, 2.7 μm and visible emission are fully discussed. • Enhanced 2.7 μm emission is achieved from the bulk glasses. • An Er{sup 3+} doped fiber is successfully drawn and strong upconversion emission is observed in the fiber. - Abstract: Emissions at 2.7 μm from telluride glasses with various Er{sub 2}O{sub 3} doping concentrations are investigated. The prepared glasses have excellent thermostability and high rare-earth solubility. Judd–Ofelt parameters are calculated based on the absorption spectra. A large emission cross section (1.12 × 10{sup −20} cm{sup 2}) and a high spontaneous radiative coefficient (57.8 s{sup −1}) are obtained at 2.7 μm. The fluorescence properties of glasses with different concentrations are analyzed and presented. An Er{sup 3+}-doped fiber is fabricated via a rod-in-tube technique, and the loss at 1310 nm is ∼2.1 dB/m measured by using the cut-back method. Strong upconversion emission caused by intense pump absorption is observed from the Er{sup 3+}doped fiber under excitation by a 980 nm laser diode (LD). Telluride glasses with high Er{sup 3+} doping concentration and good thermal property are prepared. Energy transfer processes for 1.5 μm, and 2.7 μm, as well as visible emission are fully discussed. Enhanced 2.7 μm emission is achieved from the bulk glass. An Er{sup 3+} doped fiber is successfully drawn, and strong upconversion emission is observed in the fiber.

  20. Field and photo-emission in a short-pulse, high-charge Cesium telluride RF photoinjector

    Science.gov (United States)

    Wisniewski, Eric E.

    A new high-charge RF gun is now operating at the Argonne Wakefield Accelerator (AWA) facility at Argonne National Laboratory (ANL). The 1.5 cell 1.3 GHz gun uses a Cesium telluride photocathode driven with a 248 nm laser to provide short-pulse, high charge electron beams for the new 75 MeV drive beamline. The high-gradient RF gun (peak field on the cathode > 80MV/m) is a key piece of the facility upgrade. The large Cs2Te photocathode (diameter > 30 mm) was fabricated in-house. The photo-injector will be used to generate high-charge, short pulse, single bunches (Q > 100 nC) and bunch-trains (Q > 1000 nC) for wakefield experiments, typically involving dielectric-loaded accelerating structures. Details of the photocathode fabrication process and the results of associated diagnostic measurements are presented, including QE measurements and work function measurements performed with a Kelvin probe. Fieldemitted dark current from the Cs2Te cathode was measured during RF conditioning and characterized. Fowler-Nordheim plots of the data are presented and compared to similar measurements made using a copper cathode in the initial phase of conditioning. The results for cesium telluride exhibited non-linear regions within the Fowler-Nordheim plots similar to previous experimental results for other p-type semiconductors. Results of quantum efficiency (QE) studies are presented with the cathode operating in both single and bunch-train modes. QE uniformity and lifetime studies are presented. During commissioning, the cesium telluride photocathode produced bunch-charge of 100 nC, breaking the previous record. No evidence of bunch-train position-dependence of QE was found when generating four-bunch trains with total charge up to 200 nC.

  1. Prospects of novel front and back contacts for high efficiency cadmium telluride thin film solar cells from numerical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Matin, M.A. [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Electrical and Electronics Engineering, Chittagong University of Engineering and Technology (CUET), Chittagong (Bangladesh); Mannir Aliyu, M.; Quadery, Abrar H. [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Amin, Nowshad [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Center of Excellence for Research in Engineering Materials (CEREM), College of Engineering, King Saud University, Riyadh 11421 (Saudi Arabia)

    2010-09-15

    Cadmium telluride (CdTe) thin film solar cell has long been recognized as a leading photovoltaic candidate for its high efficiency and low cost. A numerical simulation has been performed using AMPS-1D simulator to explore the possibility of higher efficiency and stable CdS/CdTe cell among several cell structures with indium tin oxide (ITO) and cadmium stannate (Cd{sub 2}SnO{sub 4}) as front contact material, tin oxide (SnO{sub 2}), zinc oxide (ZnO) and zinc stannate (Zn{sub 2}SnO{sub 4}) as buffer layer, and silver (Ag) or antimony telluride (Sb{sub 2}Te{sub 3}) with molybdenum (Mo) or zinc telluride (ZnTe) with aluminium (Al) as back contact material. The cell structure ITO/i-ZnO/CdS/CdS{sub x}Te{sub 1-x}/CdTe/Ag has shown the best conversion efficiency of 16.9% (Voc=0.9 V, Jsc=26.35 mA/cm{sup 2}, FF=0.783). This analysis has shown that ITO as front contact material, ZnO as buffer layer and ZnTe or Sb{sub 2}Te{sub 3} back surface reflector (BSR) are suitable material system for high efficiency (>15%) and stable CdS/CdTe cells. The cell normalized efficiency linearly decreased at a temperature gradient of -0.25%/ C for ZnTe based cells, and at -0.40%/ C for other cells. (author)

  2. Dextran coated bismuth-iron oxide nanohybrid contrast agents for computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Naha, Pratap C; Zaki, Ajlan Al; Hecht, Elizabeth; Chorny, Michael; Chhour, Peter; Blankemeyer, Eric; Yates, Douglas M; Witschey, Walter R T; Litt, Harold I; Tsourkas, Andrew; Cormode, David P

    2014-12-14

    Bismuth nanoparticles have been proposed as a novel CT contrast agent, however few syntheses of biocompatible bismuth nanoparticles have been achieved. We herein report the synthesis of composite bismuth-iron oxide nanoparticles (BION) that are based on a clinically approved, dextran-coated iron oxide formulation; the particles have the advantage of acting as contrast agents for both CT and MRI. BION were synthesized and characterized using various analytical methods. BION CT phantom images revealed that the X-ray attenuation of the different formulations was dependent upon the amount of bismuth present in the nanoparticle, while T2-weighted MRI contrast decreased with increasing bismuth content. No cytotoxicity was observed in Hep G2 and BJ5ta cells after 24 hours incubation with BION. The above properties, as well as the yield of synthesis and bismuth inclusion efficiency, led us to select the Bi-30 formulation for in vivo experiments, performed in mice using a micro-CT and a 9.4 T MRI system. X-ray contrast was observed in the heart and blood vessels over a 2 hour period, indicating that Bi-30 has a prolonged circulation half-life. Considerable signal loss in T2-weighted MR images was observed in the liver compared to pre-injection scans. Evaluation of the biodistribution of Bi-30 revealed that bismuth is excreted via the urine, with significant concentrations found in the kidneys and urine. In vitro experiments confirmed the degradability of Bi-30. In summary, dextran coated BION are biocompatible, biodegradable, possess strong X-ray attenuation properties and also can be used as T2-weighted MR contrast agents.

  3. Bismuth oxide aqueous colloidal nanoparticles inhibit Candida albicans growth and biofilm formation

    Directory of Open Access Journals (Sweden)

    Hernandez-Delgadillo R

    2013-04-01

    Full Text Available Rene Hernandez-Delgadillo,1 Donaji Velasco-Arias,3 Juan Jose Martinez-Sanmiguel,2 David Diaz,3 Inti Zumeta-Dube,3 Katiushka Arevalo-Niño,1 Claudio Cabral-Romero2 1Facultad de Ciencias Biológicas, Instituto de Biotecnologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Mexico; 2Facultad de Odontología, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, México; 3Facultad de Quimica, Universidad Nacional Autonoma de Mexico, UNAM, Distrito Federal, México Abstract: 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

  4. Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm

    Directory of Open Access Journals (Sweden)

    Hernandez-Delgadillo R

    2012-04-01

    Full Text Available Rene Hernandez-Delgadillo1, Donaji Velasco-Arias2, David Diaz2, Katiushka Arevalo-Niño1, Marianela Garza-Enriquez1, Myriam A De la Garza-Ramos1, Claudio Cabral-Romero11Instituto de Biotecnologia, Centro de Investigacion y Desarrollo en Ciencias de la Salud, CIDICS, Facultad de Odontologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Nuevo Leon, 2Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Distrito Federal, MexicoBackground 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.Keywords: zerovalent bismuth nanoparticles, antimicrobial agent, biofilm, Streptococcus mutans

  5. NaBH{sub 4}/[bmim]BF{sub 4}: a new reducing system to access vinyl selenides and tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Lenardao, Eder J.; Goncalves, Loren C.C.; Mendes, Samuel R.; Saraiva, Maiara T.; Alves, Diego; Jacob, Raquel G.; Perin, Gelson, E-mail: lenardao@ufpel.edu.b [Universidade Federal de Pelotas (UFPel), RS (Brazil). Inst. de Quimica e Geociencias. Lab. de Sintese Organica Limpa (LASOL)

    2010-07-01

    A general and simple method for the synthesis of vinyl selenides and tellurides starting from terminal alkynes and diorganyl chalcogenides using NaBH{sub 4} and [bmim]BF{sub 4} as a recyclable solvent was developed. This efficient and improved method furnishes the corresponding vinyl chalcogenides preferentially with Z configuration. We also observed that when the same protocol was applied to phenyl acetylene, (E)-bis-phenylchalcogeno styrenes were obtained in good yields and high selectivity. The ionic liquid was reused up three times without lost of efficiency. (author)

  6. Iron isotope constraints on the mineralization processes of the Sandaowanzi telluride gold deposit, NE China

    Science.gov (United States)

    Li, Xingxing; Liu, Junlai; Lu, Di; Ren, Shunli; Liu, Zhengyang

    2016-04-01

    Iron isotopes have been widely applied to interpret the fluid evolution, supergene alteration and the metallogenic material sources of the hydrothermal deposit. It may also have significant potentials on the research of the deposit. The Sandaowanzi telluride gold deposit, located in the Great Hinggan Range metallogenic Belt in NE China, is a large epithermal gold deposit of low-sulphidation type. It has a total reserve of ≥25t of Au and an average of 15 g/t. Gold-bearing quartz veins or gold lodes strike to the NW and dip 50-80°northeastward. Ore bodies, including low-grade ores along margins and high-grade ores in the central parts, principally occur in quartz veins. More than the 95 percent Au budgets are hosted in gold-silver tellurides. A six-stage paragenetic sequence of mineralization is revealed according to the compositions and microstructures of the mineral assemblages. Although sulfide minerals in the bonanza quartz veins are rare, pyrite are widespread in quartz veins and altered host rocks. Meanwhile there are always chalcopyrite veins within bonanza quartz veins. Pyrite Fe isotope compositions from different levels (from +50m to +210m) of the main ore body of the Sandaowanzi gold ore deposit are investigated. There is an overall variation in δ57Fe values from -0.09 to +0.99 (av. 0.33). Among them, twenty three samples from different mining levels give positiveδ57Fe values, with the maximum positive value at the economic bonanza ores (level +130m). Four samples, however, possess negative values, one at level 170m, one at level 130m, and two at level 50m, respectively. The two negative values from the levels 170m and 130m are near the cores of the high grade ore body. The two negative values from the level 50m occur at one end of the lode ore body. The above data set shows that the δ57Fe values are not homogeneous at different levels of the ore body. On the other hand, a general trend for the positive values is that the highest δ57Fe value is

  7. A Fumonisins Immunosensor Based on Polyanilino-Carbon Nanotubes Doped with Palladium Telluride Quantum Dots

    Directory of Open Access Journals (Sweden)

    Milua Masikini

    2014-12-01

    Full Text Available An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs and poly(2,5-dimethoxyaniline-multi-wall carbon nanotubes (PDMA-MWCNT. Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA gave a linear range of 7 to 49 ng L−1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng−1 and 0.46 pg L−1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI for fumonisins (the sum of FB1, FB2, and FB3 established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg−1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA for protection of human consumption (2–4 mg L−1.

  8. Novel doxorubicin loaded PEGylated cuprous telluride nanocrystals for combined photothermal-chemo cancer treatment.

    Science.gov (United States)

    Wang, Xianwen; Ma, Yan; Chen, Huajian; Wu, Xiaoyi; Qian, Haisheng; Yang, Xianzhu; Zha, Zhengbao

    2017-02-06

    Recently, combined photothermal-chemo therapy has attracted great attention due to its enhanced anti-tumor efficiency via synergistic effects. Herein, PEGylated cuprous telluride nanocrystals (PEGylated Cu2Te NCs) were developed as novel drug nanocarriers for combined photothermal-chemo treatment of cancer cells. PEGylated Cu2Te NCs were fabricated through a simple two-step process, comprised of hot injection and thin-film hydration. The as-prepared PEGylated Cu2Te NCs (average diameter of 5.21±1.05nm) showed a noticeable photothermal conversion efficiency of 33.1% and good capacity to load hydrophobic anti-cancer drug. Due to the protonated amine group at low pH, the doxorubicin (DOX)-loaded PEGylated Cu2Te NCs (PEGylated Cu2Te-DOX NCs) exhibited an acidic pH promoted drug release profile. Moreover, a three-parameter model, which considers the effects of drug-carrier interactions on the initial burst release and the sustained release of drug from micro- and nano-sized carriers, was used to gain insight into how pH and laser irradiation affect drug release from PEGylated Cu2Te-DOX NCs. Based on the results from in vitro cell study, PEGylated Cu2Te-DOX NCs revealed remarkably photothermal-chemo synergistic effect to HeLa cells, attributed to both the PEGylated Cu2Te NCs mediated photothermal ablation and enhanced cellular uptake of the drug. Thus, our results encourage the usage of Cu2Te-DOX drug nanocarriers for enhanced treatment of cancer cells by combined photothermal-chemo therapy.

  9. Spectroscopic, microscopic, and internal stress analysis in cadmium telluride grown by close-space sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Manciu, Felicia S., E-mail: fsmanciu@utep.edu [Department of Physics, The University of Texas at El Paso, El Paso, TX 79968 (United States); Salazar, Jessica G. [Department of Physics, The University of Texas at El Paso, El Paso, TX 79968 (United States); Diaz, Aryzbe; Quinones, Stella A. [Department of Electrical and Computer Engineering, The University of Texas at El Paso, El Paso, TX 79968 (United States)

    2015-08-31

    High quality materials with excellent ordered structure are needed for developing photovoltaic and infrared devices. With this end in mind, the results of our research prove the importance of a detailed, comprehensive spectroscopic and microscopic analysis in assessing cadmium telluride (CdTe) characteristics. The goal of this work is to examine not only material crystallinity and morphology, but also induced stress in the deposit material. A uniform, selective growth of polycrystalline CdTe by close-space sublimation on patterned Si(111) and Si(211) substrates is demonstrated by scanning electron microscopy images. Besides good crystallinity of the samples, as revealed by both Raman scattering and Fourier transform infrared absorption investigations, the far-infrared transmission data also show the presence of surface optical phonon modes, which is direct evidence of confinement in such a material. The qualitative identification of the induced stress was achieved by performing confocal Raman mapping microscopy on sample surfaces and by monitoring the existence of the rock-salt and zinc-blende structural phases of CdTe, which were associated with strained and unstrained morphologies, respectively. Although the induced stress in the material is still largely due to the high lattice mismatch between CdTe and the Si substrate, the current results provide a direct visualization of its partial release through the relaxation effect at crystallite boundaries and of preferential growth directions of less strain. Our study, thus offers significant value for improvement of material properties, by targeting the needed adjustments in the growth processes. - Highlights: • Assessing the characteristics of CdTe deposited on patterned Si substrates • Proving the utility of confocal Raman microscopy in monitoring the induced stress • Confirming the partial stress release through the grain boundary relaxation effect • Demonstrating the phonon confinement effect in low

  10. Development and evaluation of polycrystalline cadmium telluride dosimeters for accurate quality assurance in radiation therapy

    Science.gov (United States)

    Oh, K.; Han, M.; Kim, K.; Heo, Y.; Moon, C.; Park, S.; Nam, S.

    2016-02-01

    For quality assurance in radiation therapy, several types of dosimeters are used such as ionization chambers, radiographic films, thermo-luminescent dosimeter (TLD), and semiconductor dosimeters. Among them, semiconductor dosimeters are particularly useful for in vivo dosimeters or high dose gradient area such as the penumbra region because they are more sensitive and smaller in size compared to typical dosimeters. In this study, we developed and evaluated Cadmium Telluride (CdTe) dosimeters, one of the most promising semiconductor dosimeters due to their high quantum efficiency and charge collection efficiency. Such CdTe dosimeters include single crystal form and polycrystalline form depending upon the fabrication process. Both types of CdTe dosimeters are commercially available, but only the polycrystalline form is suitable for radiation dosimeters, since it is less affected by volumetric effect and energy dependence. To develop and evaluate polycrystalline CdTe dosimeters, polycrystalline CdTe films were prepared by thermal evaporation. After that, CdTeO3 layer, thin oxide layer, was deposited on top of the CdTe film by RF sputtering to improve charge carrier transport properties and to reduce leakage current. Also, the CdTeO3 layer which acts as a passivation layer help the dosimeter to reduce their sensitivity changes with repeated use due to radiation damage. Finally, the top and bottom electrodes, In/Ti and Pt, were used to have Schottky contact. Subsequently, the electrical properties under high energy photon beams from linear accelerator (LINAC), such as response coincidence, dose linearity, dose rate dependence, reproducibility, and percentage depth dose, were measured to evaluate polycrystalline CdTe dosimeters. In addition, we compared the experimental data of the dosimeter fabricated in this study with those of the silicon diode dosimeter and Thimble ionization chamber which widely used in routine dosimetry system and dose measurements for radiation

  11. Simultaneous Analysis of the 2nu2, nu1, and nu3 Bands of Hydrogen Telluride

    Science.gov (United States)

    Flaud; Betrencourt; Arcas; Burger; Polanz; Lafferty

    1997-04-01

    Spectra of a natural sample of hydrogen telluride as well as a spectrum of monoisotopic H2 130Te have been recorded by means of Fourier transform spectrometry with a resolution of 0.003 cm-1 in the spectral domain 7.5-4.3 μm where it is easy to observe the main absorbing bands nu1 and nu3. We have located and assigned for the first time the 2nu2 band which appears in the lower wavenumber range of the recorded spectral domain near 1700 cm-1. It proved necessary to treat simultaneously the three states (020), (100), and (001). nu1 and nu3 are indeed Coriolis-coupled vibration-rotation bands and it was observed that a few rotational levels of (001) could not be fitted to within their experimental accuracy without considering the second-order Coriolis interaction between the rotational levels of (020) and (001). In this way all the experimental levels were calculated to within the experimental uncertainty, and precise sets of vibrational energies and rotational and coupling constants were obtained for the seven most abundant H2Te isotopic species, namely H2 130Te, H2 128Te, H2 126Te, H2 125Te, H2 124Te, H2 123Te, and H2 122Te. For the most abundant isotopic species H2 130Te the bands centers arenu0 (2nu2) = 1715.9568, nu0 (nu1) = 2065.2709, nu0 (nu3) = 2072.1101 cm-1. Copyright 1997Academic Press

  12. Mercury-Cadmium-Telluride Focal Plane Array Performance Under Non-Standard Operating Conditions

    Science.gov (United States)

    Richardson, Brandon S.; Eastwood, Michael L.; Bruce, Carl F.; Green, Robert O.; Coles, J. B.

    2011-01-01

    This paper highlights a new technique that allows the Teledyne Scientific & Imaging LLC TCM6604A Mercury-Cadmium-Telluride (MCT) Focal Plane Array (FPA) to operate at room temperature. The Teledyne MCT FPA has been a standard in Imaging Spectroscopy since its creation in the 1980's. This FPA has been used in applications ranging from space instruments such as CRISM, M3 and ARTEMIS to airborne instruments such as MaRS and the Next Generation AVIRIS Instruments1. Precise focal plane alignment is always a challenge for such instruments. The current FPA alignment process results in multiple cold cycles requiring week-long durations, thereby increasing the risk and cost of a project. These alignment cycles are necessary because optimal alignment is approached incrementally and can only be measured with the FPA and Optics at standard operating conditions, requiring a cold instrument. Instruments using this FPA are normally cooled to temperatures below 150K for the MCT FPA to properly function. When the FPA is run at higher temperatures the dark current increases saturating the output. This paper covers the prospect of warm MCT FPA operation from a theoretical and experimental perspective. We discuss the empirical models and physical laws that govern MCT material properties and predict the optimal settings that will result in the best MCT PA performance at 300K. Theoretical results are then calculated for the proposed settings. We finally present the images and data obtained using the actual system with the warm MCT FPA settings. The paper concludes by emphasizing the strong positive correlation between the measured values and the theoretical results.

  13. The crystal structures and powder diffraction patterns of the uranium tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, R.L. (State Univ. of New York, Alfred, NY (USA). Inst. of Ceramic Superconductivity); Nichols, M.C.; Boehme, D.R. (Sandia National Labs., Livermore, CA (USA))

    1990-10-03

    A critical review of all of the reported structures and powder diffraction patterns in the uranium telluride system has been undertaken. Structures that are correct: Cubic -- UTe: no experimental pattern exists. Retain calculated 15--865. Cubic --U{sub 3}Te{sub 4}: retain the poor quality 12--610 but adopt the pattern calculated here. Cubic U{sub 2}Te{sub 3}: no experimental pattern exists. Adopt pattern calculated here. Orthorhombic UTe{sub 2}: Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Orthorhombic {beta}UTe{sub 3}: Adopt pattern calculated here. Orthorhombic UTe{sub 5}: Adopt the new pattern of Boehme et al. Structures in need of refinement: Orthorhombic U{sub 2}Te{sub 3}:Adopt pattern calculated here over 34--807. Hexagonal U{sub 7}Te{sub 12}: Adopt pattern calculated here but retain 24--1368. Orthorhombic UTe{sub 1.78}: Adopt pattern calculated here and retain our modified 21--1404 reported for U{sub 4}Te{sub 7}. Orthorhombic UTe{sub 2.5}: Adopt pattern calculated here. Orthorhombic UTe{sub 3.4}: Accept recent pattern of Boehme et al. Phases for which no structures or reliable patterns exist: Orthorhombic U{sub 3}Te{sub 4}: no published pattern. Tetragonal U{sub 3}Te{sub 5}: three patterns 21--1407, 34--766 and 34--896 exit but all are of very poor quality. Phases which probably do not exist: Tetragonal UTe{sub 1.78}, Tetragonal UTe{sub 2}, Cubic UTe{sub 2} U{sub 3}Te{sub 7}(21--1402), U{sub 3}Te{sub 8}(21--1406).

  14. Bismuth nanoparticles synthesized by laser ablation in lubricant oils for tribological tests

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Castañeda, M., E-mail: mar.floc@hotmail.com [Universidad Autónoma del Estado de México, Av. Instituto Literario No. 100, Oriente Col. Centro, Toluca, Estado de México C.P. 50000, México (Mexico); Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca s/n, La Marquesa, Ocoyoacac, Edo. de México C.P. 52750, México (Mexico); Camps, E. [Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca s/n, La Marquesa, Ocoyoacac, Edo. de México C.P. 52750, México (Mexico); Camacho-López, M. [Universidad Autónoma del Estado de México, Av. Instituto Literario No. 100, Oriente Col. Centro, Toluca, Estado de México C.P. 50000, México (Mexico); Muhl, S. [Instituto de Investigación en Materiales (UNAM), Circuito Exterior, Ciudad Universitaria, Coyoacán, 04510 México, D.F., México (Mexico); and others

    2015-09-15

    Highlights: • Bismuth nanoparticles have been obtained by laser ablation of solids in liquids. • The technique allows controlling the size and concentration of the samples. • Bi np’s in base oils can improve the tribological characteristics of the lubricant. - Abstract: The improvement of the tribological properties of mineral base oils through the addition of bismuth nanoparticles as an additive, together with the idea of obtaining lubricants free of heavy metals, was evaluated. Bismuth nanoparticles were produced directly in the heavy and light viscosity mineral base oils (BS900 and BS6500) using the technique of laser ablation of solids immersed in liquids. Transmission electron microscopy measurements showed the presence of pure bismuth nanoparticles. Small Angle X-ray Scattering (SAXS) measurements showed that the average size of the nanoparticles was between 7 and 65 nm depending on the experimental conditions used. The tribological properties of the base oil with the bismuth nanoparticles additives were evaluated using a four-ball tester. Tests were performed using the base oil with and without Bi nanoparticles. It was observed that the coefficient of friction of the oil decrease with an increasing concentration of the nanoparticles. The results also showed that the wear rate was reduced when the Bi nanoparticle additives were used.

  15. Bismuth Modified Carbon-Based Electrodes for the Determination of Selected Neonicotinoid Insecticides

    Directory of Open Access Journals (Sweden)

    Marko Rodić

    2011-05-01

    Full Text Available Two types of bismuth modified electrodes, a bismuth-film modified glassy carbon (BiF-GCE and a bismuth bulk modified carbon paste, were applied for the determination of selected nitroguanidine neonicotinoid insecticides. The method based on an ex situ prepared BiF-GCE operated in the differential pulse voltammetric (DPV mode was applied to determine clothianidin in the concentration range from 2.5 to 23 μg cm−3 with a relative standard deviation (RSD not exceeding 1.5%. The tricresyl phosphate-based carbon paste electrodes (TCP-CPEs, bulk modified with 5 and 20 w/w% of bismuth, showed a different analytical performance in the determination of imidacloprid, regarding the peak shape, potential window, and noise level. The TCP-CPE with 5% Bi was advantageous, and the developed DPV method based on it allowed the determination in the concentration range from 1.7 to 60 μg cm−3 with an RSD of 2.4%. To get a deeper insight into the morphology of the bismuth-based sensor surfaces, scanning electron microscopic measurements were performed of both the surface film and the bulk modified electrodes.

  16. Electrochemical study on determination of diffusivity, activity and solubility of oxygen in liquid bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, Rajesh [Liquid Metals and Structural Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Gnanasekaran, T. [Liquid Metals and Structural Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)]. E-mail: gnani@igcar.ernet.in; Srinivasa, Raman S. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400 076 (India)

    2006-06-15

    Diffusivity of oxygen in liquid bismuth was measured by potentiostatic method and is given bylg(D{sub O}{sup Bi}/cm{sup 2}.s{sup -1})(+/-0.042)=-3.706-1377/(TK{sup -1})(804bismuth was determined by coulometric titrations and using the measured data standard free energy of dissolution of oxygen in liquid bismuth was derived for the reaction:1/2O{sub 2}(g)=[O]{sub Bi}(at.%)and is given by{delta}G{sub O(Bi)}{sup o}/(J.g-atomO{sup -1})(+/-720)=-108784+20.356TK{sup -1}(753bismuth was derived as a function of temperature and is given by the following expressions:lg(S/at%O)(+/-0.05)=-4476/TK{sup -1}+4.05(753bismuth is compared with the literature data.

  17. Facile solvothermal synthesis of a graphene nanosheet-bismuth oxide composite and its electrochemical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huanwen [Key Laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Hu Zhongai, E-mail: zhongai@nwnu.edu.c [Key Laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Chang Yanqin; Chen Yanli; Lei Ziqiang; Zhang Ziyu; Yang Yuying [Key Laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2010-12-01

    This work demonstrates a novel and facile route for preparing graphene-based composites comprising of metal oxide nanoparticles and graphene. A graphene nanosheet-bismuth oxide composite as electrode materials of supercapacitors was firstly synthesized by thermally treating the graphene-bismuth composite, which was obtained through simultaneous solvothermal reduction of the colloidal dispersions of negatively charged graphene oxide sheets in N,N-dimethyl formamide (DMF) solution of bismuth cations at 180 {sup o}C. The morphology, composition, and microstructure of the composites together with pure graphite oxide, and graphene were characterized using powder X-ray diffraction (XRD), FT-IR, field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), thermogravimetry and differential thermogravimetry (TG-DTG). The electrochemical behaviors were measured by cyclic voltammogram (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The specific capacitance of 255 F g{sup -1} (based on composite) is obtained at a specific current of 1 A g{sup -1} as compared with 71 F g{sup -1} for pure graphene. The loaded-bismuth oxide achieves a specific capacitance as high as 757 F g{sup -1} even at 10 A g{sup -1}. In addition, the graphene nanosheet-bismuth oxide composite electrode exhibits the excellent rate capability and well reversibility.

  18. Synthesis and performance of bismuth trioxide nanoparticles for high energy gas generator use.

    Science.gov (United States)

    Martirosyan, K S; Wang, L; Vicent, A; Luss, D

    2009-10-01

    Our experiments showed that the combustion of an Al-Bi2O3 nanoparticle mixture generated the highest pressure pulse among common nanothermite reactions and can potentially be used as a nanoenergetic gas generator. The combustion front propagation velocity and rate of energy release increased by up to three orders of magnitude when the particle size was reduced to a nanosize range for both the aluminum and the oxidizer. We developed a novel one-step (metal nitrate-glycine) combustion synthesis of nanostructured amorphous-like and highly crystalline bismuth trioxide nanoparticles. The combustion synthesis was conducted using a solution of molten bismuth nitrate as an oxidizer and glycine as a fuel. The glycine was completely combusted during the thermal decomposition of the bismuth nitrate pentahydrate and generated a temperature front that propagated through the sample. Increasing the fuel concentration increased the maximum combustion temperature from 280 to 1200 degrees C and the Bi2O3 particle size from 20 to 100 nm. The oxidizer/fuel ratio had a strong impact on the bismuth trioxide particle crystallinity. At low temperature (280 degrees C), amorphous-like bismuth trioxide nanoparticles formed, while at T > or =370 degrees C the structures were crystalline. A peak pressure of approximately 12 MPa and a thermal front propagating velocity of approximately 2500 m s(-1) were achieved during the combustion of an Al-Bi2O3 mixture containing 80 wt% of the synthesized Bi2O3 crystalline nanoparticles (size: 40-50 nm).

  19. How reliable are environmental data on 'orphan' elements? The case of bismuth concentrations in surface waters.

    Science.gov (United States)

    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.

  20. Computational chemistry calculations of stability for bismuth nanotubes, fullerene-like structures and hydrogen-containing nanostructures.

    Science.gov (United States)

    Kharissova, Oxana V; Osorio, Mario; Vázquez, Mario Sánchez; Kharisov, Boris I

    2012-08-01

    Using molecular mechanics (MM+), semi-empirical (PM6) and density functional theory (DFT) (B3LYP) methods we characterized bismuth nanotubes. In addition, we predicted the bismuth clusters {Bi(20)(C(5V)), Bi(24)(C(6v)), Bi(28)(C(1)), B(32)(D(3H)), Bi(60)(C(I))} and calculated their conductor properties.

  1. Magnetic and Electrical Characteristics of Bismuth Ferrite, Depending on the Impurities, Method of Preparation and Size of the Nanoparticles

    Directory of Open Access Journals (Sweden)

    V.M. Sarnatsky

    2016-10-01

    Full Text Available The prospect of application of the multiferroics in devices and spintronics devices is shown. A comparative analysis of magnetic and dielectric properties of nanostructures based on bismuth ferrite which were synthesized by various ways was made. The results of studies of the structure and properties of the nanostructured bismuth ferrite powder, synthesized by combustion of nitrate - organic precursors, are presented.

  2. One-dimensional Topological Edge States of Bismuth Bilayers

    Science.gov (United States)

    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)

  3. Antibacterial effect of bismuth subsalicylate nanoparticles synthesized by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Castañeda, Mariela [Instituto Nacional de Investigaciones Nucleares (Mexico); Vega-Jiménez, Alejandro L., E-mail: argelia.almaguer@mac.com; Almaguer-Flores, Argelia [Universidad Nacional Autónoma de México, Facultad de Odontología, DEPeI, I (Mexico); Camps, Enrique; Pérez, Mario [Instituto Nacional de Investigaciones Nucleares (Mexico); Silva-Bermudez, Phaedra [Instituto Nacional de Rehabilitación, Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa (Mexico); Berea, Edgardo [FarmaQuimia SA de CV. (Mexico); Rodil, Sandra E. [Universidad Nacional Autónoma de México, Instituto de Investigaciones en Materiales (Mexico)

    2015-11-15

    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.

  4. Shape-dependent photocatalytic activities of bismuth subcarbonate nanostructures.

    Science.gov (United States)

    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.

  5. Dielectric and Impedance Spectroscopy of Barium Bismuth Vanadate Ferroelectrics

    Science.gov (United States)

    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.

  6. Mechanically Activated Synthesis of Nanocrystalline Powders of Ferroelectric Bismuth Vanadate

    Science.gov (United States)

    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.

  7. Aromatic amino acids in high selectivity bismuth(III) recognition.

    Science.gov (United States)

    Ghatak, Sumanta Kumar; Dey, Debarati; Sen, Souvik; Sen, Kamalika

    2013-04-21

    The three aromatic amino acids, tyrosine, tryptophan and phenylalanine, play different physiological roles in life processes. Metal ions capable of binding these amino acids may aid in the reduction of effective concentration of these amino acids in any physiological system. Here we have studied the efficacy of some heavy metals for their complexation with these three amino acids. Bismuth has been found to bind selectively with these aromatic amino acids and this was confirmed using spectrofluorimetric, spectrophotometric and cyclic voltammetric studies. The series of heavy metals has been chosen because each of these metals remains associated with the others at very low concentration levels and Bi(III) is the least toxic amongst the other elements. So, selective recognition for Bi(III) would also mean no response for the other heavy elements if contaminants are present even at low concentration levels. The affinity towards these amino acids has been found to be in the order tryptophan phenylalanine amino acids have been calculated using Benesi-Hildebrand equations and the corresponding free energy change has also been calculated. The values of the association constants obtained from BH equations using absorbance values corroborate with the Stern-Volmer constants obtained from fluorimetric studies. The evidence for complexation is also supported by the results of cyclic voltammetry.

  8. Optical analysis of samarium doped sodium bismuth silicate glass

    Science.gov (United States)

    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.

  9. Bismuth nanoparticles integration into heavy metal electrochemical stripping sensor.

    Science.gov (United States)

    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.

  10. Modular Lead-Bismuth Fast Reactors in Nuclear Power

    Directory of Open Access Journals (Sweden)

    Vladimir Petrochenko

    2012-09-01

    Full Text Available On the basis of the unique experience of operating reactors with heavy liquid metal coolant–eutectic lead-bismuth alloy in nuclear submarines, the concept of modular small fast reactors SVBR-100 for civilian nuclear power has been developed and validated. The features of this innovative technology are as follows: a monoblock (integral design of the reactor with fast neutron spectrum, which can operate using different types of fuel in various fuel cycles including MOX fuel in a self-providing mode. The reactor is distinct in that it has a high level of self-protection and passive safety, it is factory manufactured and the assembled reactor can be transported by railway. Multipurpose application of the reactor is presumed, primarily, it can be used for regional power to produce electricity, heat and for water desalination. The Project is being realized within the framework of state-private partnership with joint venture OJSC “AKME-Engineering” established on a parity basis by the State Atomic Energy Corporation “Rosatom” and the Limited Liability Company “EuroSibEnergo”.

  11. On the use of bismuth as a neutron filter

    CERN Document Server

    Adib, M

    2003-01-01

    A formula is given which, for neutron energies in the range 10 sup - sup 4 bismuth temperature and crystalline form. Computer programs have been developed which allow calculations for the Bi rhombohedral structure in its poly-crystalline form and its equivalent hexagonal close-packed structure. The calculated total neutron cross-sections for poly-crystalline Bi at different temperatures were compared with the measured values. An overall agreement is indicated between the formula fits and experimental data. Agreement was also obtained for values of Bi-single crystals, at room and liquid nitrogen temperatures. A feasibility study for use of Bi in powdered form, as a cold neutron filter, is detailed in terms of the optimum Bi-single crystal thickness, mosaic spread, temperature and cutting plane for efficient transmission of thermal-reactor neutrons, and also for rejection of the accom...

  12. Synthesis and characterization of bismuth zinc niobate pyrochlore nanopowders

    Directory of Open Access Journals (Sweden)

    Sonia Maria Zanetti

    2007-09-01

    Full Text Available Bismuth zinc niobate pyrochlores Bi1.5ZnNb1.5O7 (alpha-BZN, and Bi2(Zn1/3Nb2/32O 7 (beta-BZN have been synthesized by chemical method based on the polymeric precursors. The pyrochlore phase was investigated by differential scanning calorimetry, infrared spectroscopy, and X ray diffraction. Powder and sintered pellets morphology was examined by scanning electron microscopy. The study of alpha-BZN phase formation reveals that, at 500 °C, the pyrochlore phase was already present while a single-phased nanopowder was obtained after calcination at 700 °C. The crystallization mechanism of the beta-BZN is quite different, occurring through the crystallization of alpha-BZN and BiNbO4 intermediary phases. Both compositions yielded soft agglomerated powders. alpha-BZN pellets, sintered at 800 °C for 2 hours, presented a relative density of 97.3% while those of beta-BZN, sintered at 900 °C for 2 hours, reached only 91.8%. Dielectric constant and dielectric loss, measured at 1 MHz, were 150 and 4 x/10-4 for a-BZN, and 97 and 8 x 10-4 for beta-BZN.

  13. Pressure effects on crystal and electronic structure of bismuth tellurohalides

    Science.gov (United States)

    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.

  14. Thermoelectric characterization of individual bismuth selenide topological insulator nanoribbons

    Science.gov (United States)

    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

    Energy Technology Data Exchange (ETDEWEB)

    Andreici, Emiliana-Laura, E-mail: andreicilaura@yahoo.com [Department of Physics, West University of Timisoara, Bd. V. Parvan 4,300223 Timisoara (Romania); Petkova, Petya [Shumen University “Konstantin Preslavsky”, 115 Universitetska street, 9712 Shumen (Bulgaria); Avram, Nicolae M. [Department of Physics, West University of Timisoara, Bd. V. Parvan 4,300223 Timisoara (Romania); Academy of Romanian Scientists, Independentei 54, 050094-Bucharest (Romania)

    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. Bismuth alloying properties in GaAs nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Lu [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, PO Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon.bupt@gmail.com [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, PO Box 72, Beijing 100876 (China); Cao, Huawei; Cai, Ningning; Yu, Zhongyuan [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, PO Box 72, Beijing 100876 (China); Gao, Tao [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    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.

  17. Insights into the growth of bismuth nanoparticles on 2D structured BiOCl photocatalysts: an in situ TEM investigation.

    Science.gov (United States)

    Chang, Xiaofeng; Wang, Shuangbao; Qi, Qi; Gondal, Mohammed A; Rashid, Siddique G; Gao, Si; Yang, Deyuan; Shen, Kai; Xu, Qingyu; Wang, Peng

    2015-09-28

    The synthetic techniques for novel photocatalytic crystals had evolved by a trial-and-error process that spanned more than two decades, and an insight into the photocatalytic crystal growth process is a challenging area and prerequisite for achieving an excellent photoactivity. Bismuth nanoparticle based hybrids, such as Bi/BiOCl composites, have recently been investigated as highly efficient photocatalytic systems because of the localized surface plasmon resonance (LSPR) of nanostructured bismuth. In this work, the observation towards the formation and growth of bismuth nanoparticles onto 2D structured BiOCl photocatalysts has been performed using a transmission electron microscope (TEM) directly in real time. The growth of bismuth nanoparticles on BiOCl nanosheets can be emulated and speeded up driven by the electron beam (e(-) beam) in TEM. The crystallinity, growth and the elemental evolution during the formation of bismuth nanoparticles have also been probed in this work.

  18. Review - Fabrication of crystal-oriented barium-bismuth titanate ceramics in high magnetic field and subsequent reaction sintering

    Directory of Open Access Journals (Sweden)

    Satoshi Tanaka, Yusuke Tomita, Ryoichi Furushima, Hiroyuki Shimizu, Yutaka Doshida and Keizo Uematsu

    2009-01-01

    Full Text Available High magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 μ m were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a- and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100 ° C.

  19. Overview of the use of ATHENA for thermal-hydraulic analysis of systems with lead-bismuth coolant

    Energy Technology Data Exchange (ETDEWEB)

    C. B. Davis; A. S. Shieh

    2000-04-02

    The INEEL and MIT are investigating the suitability of lead-bismuth cooled fast reactor for producing low-cost electricity as well as for actinide burning. This paper is concerned with the general area of thermal-hydraulics of lead-bismuth cooled reactors. The ATHENA code is being used in the thermal-hydraulic design and analysis of lead-bismuth cooled reactors. The ATHENA code was reviewed to determine its applicability for simulating lead-bismuth cooled reactors. Two modifications were made to the code as a result of this review. Specifically, a correlation to represent heat transfer from rod bundles to a liquid metal and a void correlation based on data taken in a mixture of lead-bismuth and steam were added the code. The paper also summarizes the analytical work that is being performed with the code and plans for future analytical work.

  20. Overview of the Use of ATHENA for Thermal-Hydraulic Analysis of Systems with Lead-Bismuth Coolant

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Cliff Bybee; Shieh, Arthur Shan Luk

    2000-04-01

    The INEEL and MIT are investigating the suitability of lead-bismuth cooled fast reactor for producing low-cost electricity as well as for actinide burning. This paper is concerned with the general area of thermal-hydraulics of lead-bismuth cooled reactors. The ATHENA code is being used in the thermal-hydraulic design and analysis of lead-bismuth cooled reactors. The ATHENA code was reviewed to determine its applicability for simulating lead-bismuth cooled reactors. Two modifications were made to the code as a result of this review. Specifically, a correlation to represent heat transfer from rod bundles to a liquid metal and a void correlation based on data taken in a mixture of lead-bismuth and steam were added the code. The paper also summarizes the analytical work that is being performed with the code and plans for future analytical work.

  1. Experimental investigation of the shock response of bismuth under one-dimensional shock-loading

    Science.gov (United States)

    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.

  2. Radioactive Iodine (I-129) Gas Adsorption by Using Bismuth-Embedded SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Hwan; Cho, Yong-Jun; Park, Jang Jin; Ahn, Do-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Man-Sung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    The efficient capture of the long-lived I-129, released as off-gas from nuclear fuel reprocessing, have been of significant concern in the waste management field. In this study, bismuth-embedded SBA-15 mesoporous silica was firstly applied for iodine capture and storage. SBA-15 was functionalized with thiol (-SH) groups, followed by bismuth adsorption with Bi-S bonding, which was thermally treated to form Bi{sub 2}S{sub 3} within SBA-15. The bismuth-embedded SBA-15s demonstrated high iodine loading capacities with 540 mg-I/g-sorbent maximally, which benefitted from the high surface area and porosity of SBA-15 as well as the formation of thermodynamically stable BiI{sub 3} compound. Iodine physisorption could effectively be suppressed due to the large pores present in SBA-15, resulting in chemisorption as a main mechanism for iodine confinement.

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

    Science.gov (United States)

    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.

  4. Poisoning effect of bismuth on modification behaviour of strontium in LM25 alloy

    Indian Academy of Sciences (India)

    S Farahany; A Ourdjini; M H Idris; L T Thai

    2011-10-01

    Nucleation and growth, temperature measurements andmicrostructure observations of silicon phase are presented for strontium modified Al–7%Si (LM25) cast alloy treated with bismuth. The results show that addition of bismuth in strontium modified alloys may have a poisoning effect resulting in lost modification of the silicon phase. With increasing Bi/Sr ratio, thermal analysis measurements showed that the eutectic growth temperature increased remarkably to 573°C and recalescence decreased to 0.2°C and the morphology of silicon displayed the same flakelike structure as in the unmodified alloys. Microstructural observation showed that a minimum Bi/Sr ratio of 1.2 which is equivalent to a Sr/Bi ratio of 0.43 is required for effective strontium modification and neutralization of the poisoning effect of bismuth.

  5. Facile preparation of Bi nanoparticles by novel cathodic dispersion of bulk bismuth electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xin [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Chen Shu; Huang Wei [Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Lushan Road, Changsha 410081 (China); Zheng Jufang [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Li Zelin, E-mail: lizelin@zjnu.c [Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Lushan Road, Changsha 410081 (China)

    2009-12-01

    A novel electrochemical approach has been developed to prepare clean bismuth nanoparticles (NPs) with a bulk Bi electrode in a 0.5 mol dm{sup -3} NaOH solution under highly cathodic polarization of -8 V versus a saturated mercurous sulfate electrode, requiring no any precursor ions and organic protective agents. The bulk Bi electrode can be facilely dispersed into Bi NPs at the condition of intensive hydrogen evolution. This cathodic dispersion of the bulk Bi electrode involves the formation and decomposition of unstable bismuth hydrides and the aggregation of atomic bismuth from the decomposition. Moreover, Bi{sub 2}O{sub 3} NPs have also been achieved by heating the precursor Bi NPs. Field-emission scanning electron microscopy, transmission electron microscope and X-ray diffraction were used to characterize these NPs. The as-prepared Bi NPs mainly existed in rhombohedral phase.

  6. Application of Thermodynamic Calculations to the Pyro-refining Process for Production of High Purity Bismuth

    Science.gov (United States)

    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.

  7. Optical properties of thermally reduced bismuth-doped sodium aluminosilicate glasses

    DEFF Research Database (Denmark)

    Nielsen, K.H.; Smedskjær, Morten Mattrup; Yue, Yuanzheng

    , but also concerning the metal particle formation, and the broadband near infrared luminescence. Both the inward diffusion and the infrared luminescence depend on the bismuth oxidation state. The latter can be varied by adjusting the parameters of the heat-treatment, e.g., time, temperature, and partial......Heat-treatment of multivalent ion containing glasses in a hydrogen atmosphere may cause both reduction of the multivalent ions and ionic inward diffusion, resulting in improved glass properties. Bismuth-doped glasses are also interesting objects not only concerning the reduction induced diffusion...... pressure of hydrogen. Here, we present results on the effect of the heat-treatment on the optical properties of bismuth-doped sodium aluminosilicate glasses....

  8. Melting behaviour of lead and bismuth nano-particles in quasicrystalline matrix - The role of interfaces

    Indian Academy of Sciences (India)

    Alok Singh; A P Tsai

    2003-02-01

    Nanomaterials are playing an increasingly important role in modern technologies. Interfaces are crucial in nanotechnology. In this study, we have examined the stability of nanoparticles. Major emphasis is on understanding the effect of interfaces on melting. Melting behaviour of nanocrystalline interfaces, created by embedding lead and bismuth nanoparticles in quasicrystalline matrices, was studied. Sharply faceted and coherent interfaces can be related to sharper melting transitions, while irregularly shaped and incoherent interfaces can be directly correlated with lowering of melting temperatures. It is shown here that solid lead forms a high energy interface with phason strain-free quasicrystal (resulting in a lowering of the melting temperature) while bismuth forms a low energy interface with the quasicrystal (resulting in superheating, unusual for bismuth).

  9. Design of an Actinide Burning, Lead-Bismuth Cooled Reactor That Produces Low Cost Electricity

    Energy Technology Data Exchange (ETDEWEB)

    C. Davis; S. Herring; P. MacDonald; K. McCarthy; V. Shah; K. Weaver (INEEL); J. Buongiorno; R. Ballinger; K. Doyoung; M. Driscoll; P. Hejzler; M. Kazimi; N. Todreas (MIT)

    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.

  10. Fluorescence Emission Centres and the Corresponding Infrared Fluorescence Saturation in a Bismuth-Doped Silica Fibre

    Institute of Scientific and Technical Information of China (English)

    QIU Yan-Qing; SHEN Yong-Hang

    2008-01-01

    We investigate the fluorescence characteristics of bismuth doped silica fibres with and without Al co-dopant which are fabricated by means of modified chemical vapour deposition (MCVD) technique, and find that the fluorescences in the red region (centred around 750nm) and in the infrared region (centred around 1100nm) may originate from different emission sites in the fibre. Strong upconversion phenomena are observed in both Al-codoped and non Al codoped bismuth fibres when the fibres are excited by an acoustic-optic Q-switched Nd: YVO4 laser. Both the aspects indicate that the upper energy level absorption reported in the work of the bismuth doped silica fibre lasers may result from the fluorescence emission sites that are not responsible for the infrared emission. It is thus expected that optimizing the compositions and the fabrication conditions of the fibre and then transferring more fluorescence emission centres are helpful for the infrared emission.

  11. Glass-like carbon, pyrolytic graphite or nanostructured carbon for electrochemical sensing of bismuth ion?

    Directory of Open Access Journals (Sweden)

    Jadranka Milikić

    2016-06-01

    Full Text Available Different carbon electrodes were explored for application in electroanalysis, namely for sensing of bismuth ion as model analyte. Carbon materials tested included glassy carbon, basal and edge plane pyrolytic graphite, as well as nanostructured carbonized polyaniline prepared in the presence of 3,5-dinitrosalicylic acid. Bismuth ion was chosen as model analyte as protocol for its detection and quantifications is still to be determined. Herein, anodic stripping voltammetry was used with study of effect of several parameters such as scan rate and deposition time. Electrode based on carbonized polyaniline showed the highest activity for bismuth ion sensing in terms of the highest current densities recorded both in a laboratory and in real sample, while basal plane pyrolytic graphite electrode gave the lowest limit of detection.

  12. Bismuth subcarbonate as filler particle for an Epoxy-based root canal sealer

    Directory of Open Access Journals (Sweden)

    Eduardo Schwartzer

    2013-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the addition of bismuth subcarbonate with different concentrations regarding the rheological properties of an experimental epoxy-based root canal sealer. Materials and Methods: Endodontic sealers were prepared with epoxy resin-based sealer with bismuth subcarbonate additions of 20%, 40%, 60%, 80%, 100%, and 120%. Flow, film thickness, working time, setting time, dimensional change, sorption, solubility, and cytotoxicity were studied according to the ISO standards. Data were statistically analyzed by one-way ANOVA, and Tukey multiple comparisons were used, with a significance level of 5%. Results: The flow, working time, water sorption, and solubility significantly decreased and the film thickness and dimensional change increased with higher filler particle addition. There were no statistically significant differences for setting time and cytotoxicity between the filler particle proportions. Conclusion: Experimental resin-based sealer with bismuth subcarbonate addition up to 40% can be an alternative for root canal sealer.

  13. Bismuth Passivation Technique for High-Resolution X-Ray Detectors

    Science.gov (United States)

    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).

  14. Influence of the Ion Coordination Number on Cation Exchange Reactions with Copper Telluride Nanocrystals.

    Science.gov (United States)

    Tu, Renyong; Xie, Yi; Bertoni, Giovanni; Lak, Aidin; Gaspari, Roberto; Rapallo, Arnaldo; Cavalli, Andrea; Trizio, Luca De; Manna, Liberato

    2016-06-01

    Cu2-xTe nanocubes were used as starting seeds to access metal telluride nanocrystals by cation exchanges at room temperature. The coordination number of the entering cations was found to play an important role in dictating the reaction pathways. The exchanges with tetrahedrally coordinated cations (i.e., with coordination number 4), such as Cd(2+) or Hg(2+), yielded monocrystalline CdTe or HgTe nanocrystals with Cu2-xTe/CdTe or Cu2-xTe/HgTe Janus-like heterostructures as intermediates. The formation of Janus-like architectures was attributed to the high diffusion rate of the relatively small tetrahedrally coordinated cations, which could rapidly diffuse in the Cu2-xTe NCs and nucleate the CdTe (or HgTe) phase in a preferred region of the host structure. Also, with both Cd(2+) and Hg(2+) ions the exchange led to wurtzite CdTe and HgTe phases rather than the more stable zinc-blende ones, indicating that the anion framework of the starting Cu2-xTe particles could be more easily deformed to match the anion framework of the metastable wurtzite structures. As hexagonal HgTe had never been reported to date, this represents another case of metastable new phases that can only be accessed by cation exchange. On the other hand, the exchanges involving octahedrally coordinated ions (i.e., with coordination number 6), such as Pb(2+) or Sn(2+), yielded rock-salt polycrystalline PbTe or SnTe nanocrystals with Cu2-xTe@PbTe or Cu2-xTe@SnTe core@shell architectures at the early stages of the exchange process. In this case, the octahedrally coordinated ions are probably too large to diffuse easily through the Cu2-xTe structure: their limited diffusion rate restricts their initial reaction to the surface of the nanocrystals, where cation exchange is initiated unselectively, leading to core@shell architectures. Interestingly, these heterostructures were found to be metastable as they evolved to stable Janus-like architectures if annealed at 200 °C under vacuum.

  15. Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Fan J

    2016-07-01

    Full Text Available Junpeng Fan,1–4 Ming Shao,1–4 Lu Lai,3–5 Yi Liu,3–5 Zhixiong Xie1–4,6 1College of Life Sciences, Wuhan University, 2Hubei Provincial Cooperative Innovation Center of Industrial Fermentation,3State Key Laboratory of Virology, 4Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE, 5College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 6School of Life Science and Technology, Hubei Engineering University, Xiaogan, People’s Republic of China Abstract: Cadmium telluride quantum dots (CdTe QDs are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator, combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells. Keywords: CdTe quantum dots, Saccharomyces cerevisiae, toxicity, autophagy

  16. Spin-Polarized Tunneling Study on Spin-Momentum Locking in the Topological Insulator Bismuth Selenide

    Science.gov (United States)

    Chen, Ching-Tzu; Liu, Luqiao; Richardella, Anthony; Garate, Ion; Zhu, Yu; Samarth, Nitin

    2015-03-01

    In this talk, we will demonstrate that the helical spin texture on topological insulator (TI) surfaces can be electrically detected using four-terminal tunnel junction devices with ferromagnetic top electrodes. Consistent results are obtained in both the Edelstein and spin-galvanic effect configurations, allowing a quantitative determination of the charge-spin conversion efficiency in bismuth selenide. By applying finite DC biases at the junction, we further extract the energy dependence of the effective spin polarization in bismuth selenide. The observed temperature stability up to 200K suggests that TIs can be highly promising for room-temperature spintronics applications

  17. Simultaneous enhancements in photon absorption and charge transport of bismuth vanadate photoanodes for solar water splitting

    OpenAIRE

    Kim, Tae Woo; Ping, Yuan; Galli, Giulia A.; Choi, Kyoung-Shin

    2015-01-01

    n-Type bismuth vanadate has been identified as one of the most promising photoanodes for use in a water-splitting photoelectrochemical cell. The major limitation of BiVO4 is its relatively wide bandgap (∼2.5 eV), which fundamentally limits its solar-to-hydrogen conversion efficiency. Here we show that annealing nanoporous bismuth vanadate electrodes at 350 °C under nitrogen flow can result in nitrogen doping and generation of oxygen vacancies. This gentle nitrogen treatment not only effective...

  18. Simultaneous Determination of Bismuth and Copper by Square Wave Voltammetry in The Presence of Ethylenediaminetetraacedic Acid

    OpenAIRE

    HASDEMİR, Erdoğan; KARABODUK, Kuddusi

    2010-01-01

    A sensitive and selective method for the simultaneous determination of copper and bismuth by square wave voltammetry (SWV) was developed using ethylenediaminetetraacedic acid (EDTA) as complexing agent. Factors affecting the pH and concentrations ratios of copper and bismuth were investigated. Optimal analytical conditions were  found to be: pH of 8.0, the ratio of [Cu2+]/[Bi3+] was 0.13-2.5. The limit of detection (3δ) was 1.26 × 10-7 mol dm-3 for copper,  1.30×10...

  19. Investigation on bismuth-oxide photonic crystal fiber for optical parametric amplification

    Institute of Scientific and Technical Information of China (English)

    JIN Cang; RAO Lan; YUAN Jin-hui; SHEN Xiang-wei; YU Chong-xiu

    2011-01-01

    A hexagonal solid-core bismuth-oxide micro-structure fiber is developed to balance its dispersion and nonlinearity. This simulation and calculation results show that the bismuth-oxide photonic crystal fiber (Bi-PCF) has near zero dispersion around 1550 nm. Its dispersion slop in the communication wavelength range is also relatively flat. Moreover, both nonlinear coefficient and model field distribution are obtained. Compared with the experimental results by SiO-PCF, it can be seen that the Bi-PCF shows excellent characteristics for the optical parametric amplification (OPA).

  20. Structural investigations of bismuth lead borosilicate glasses under the influence of gamma irradiation through ultrasonic studies

    Science.gov (United States)

    Bootjomchai, Cherdsak; Laopaiboon, Jintana; Laopaiboon, Raewat

    2012-04-01

    The ultrasonic velocity measurements for different compositions of irradiated bismuth lead borosilicate glasses xBi2O3-(50-x)PbO-20B2O3-30SiO2 (x=2, 4, 6, 8, and 10 mol.%) were performed at room temperature using pulse-echo technique. Densities of glass samples were measured by Archimedes' principle using n-hexane as the immersion liquid. The results from the studies show that ultrasonic velocity, elastic moduli, Poisson's ratio, microhardness, and the Debye temperature increase with increasing bismuth oxide content and increasing gamma-radiation dose (3-12 Gy).

  1. Growth morphology and structure of bismuth thin films on GaSb(110)

    DEFF Research Database (Denmark)

    Gemmeren, T. van; Lottermoser, L.; Falkenberg, G.

    1998-01-01

    Photoelectron spectroscopy, low-energy electron diffraction, scanning tunneling microscopy and surface X-ray diffraction were used to investigate the growth of thin layers of bismuth on GaSb(110). At submonolayer coverages, growth of two-dimensional islands occurs. A uniform (1 x I)-reconstructio...... that the (1 x 1)-phases formed by antimony and bismuth adsorbates on (110) surfaces of other III-V compound semiconductors are also described by the epitaxial continued layer model. (C) 1998 Elsevier Science B.V. All rights reserved....

  2. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.

    2015-01-01

    Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

  3. Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Biasotto, G. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil); Simoes, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista-Unesp, Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Pedregulho, CEP 12516-410, Guaratingueta, SP (Brazil); Foschini, C.R.; Zaghete, M.A.; Varela, J.A.; Longo, E. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)

    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.

  4. Extractive Spectrophotometric Determination of Bismuth(III in Water Using Some Ion Pairing Reagents

    Directory of Open Access Journals (Sweden)

    Abdulaziz S. Bashammakh

    2011-01-01

    Full Text Available Two novel and low cost liquid-liquid extraction methods for the separation of bismuth(III at trace level from aqueous medium have been developed. The two methods were based upon the formation of yellow colored ternary complex ion associates of tetraiodobismuth(III complex anion, BiI4- with the ion-pairing reagent 2,3,5-tetraphenyltetrazoliumchloride (Tz+.Cl– and 1, 10 phenanthroline (Phen in sulfuric acid medium. The effect of various parameters e.g. pH, organic solvent, shaking time, etc. on the preconcentration of bismuth(III from the aqueous media by the reagent was investigated. The developed colored complex ion associates [Tz+.BiI4-] and [Phen+.BiI4-] were extracted quantitatively into acetone-chloroform (1:1v/v and methyliso- butylketone (MIBK, respectively. The compositions of the formed complex ion associates [Tz+.BiI4-] and [Phen+.BiI4-] were determined by the Job's method at 500 and 490 nm, respectively. The plots of bismuth(III concentration (0-17 μg mL-1 versus absorbance of the associates at 500 and 490 nm were linear with good correlation coefficient (R2=0.998. The developed method of the ion associate [Tz+.BiI4-] two methods was applied successfully for the analysis of bismuth in water.

  5. Bismuth-embedded SBA-15 mesoporous silica for radioactive iodine capture and stable storage

    Science.gov (United States)

    Yang, Jae Hwan; Cho, Yong-Jun; Shin, Jin Myeong; Yim, Man-Sung

    2015-10-01

    Efficient capture and stable storage of the long-lived iodine-129 (129I), released as off-gas from nuclear fuel reprocessing, have been of significant concern in the waste management field. In this study, bismuth-embedded SBA-15 mesoporous silica was firstly applied for iodine capture and storage. SBA-15 was functionalized with thiol (-SH) groups, followed by bismuth adsorption with Bi-S bonding, which was thermally treated to form Bi2S3 within SBA-15. The bismuth-embedded SBA-15s demonstrated high iodine loading capacities (up to 540 mg-I/g-sorbent), which benefitted from high surface area and porosity of SBA-15 as well as the formation of thermodynamically stable BiI3 compound. Iodine physisorption was effectively suppressed due to the large pores present in SBA-15, resulting in chemisorption as a main mechanism for iodine confinement. Furthermore, a chemically durable iodine-bearing material was made with a facile post-sorption process, during which the iodine-incorporated phase was changed from BiI3 to chemically durable Bi5O7I. Thus, our results showed that both efficient capture and stabilization of 129I would be possible with the bismuth-embedded SBA-15, in contrast to other sorbents mainly focused on iodine capture.

  6. A sensitive fluorescence quenching method for determination of bismuth with tiron

    Energy Technology Data Exchange (ETDEWEB)

    Taher, Mohammad Ali; Rahimi, Mina [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Fazelirad, Hamid, E-mail: hamidfazelirad@gmail.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Department of Chemistry, Science and Research Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Young Researchers Society, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Kerman (Iran, Islamic Republic of)

    2014-01-15

    We describe a fluorescence quenching method for determination of bismuth with tiron. The method is based on the reaction of tiron by bismuth(III) in acidic media. The influence of variables such as the pH, type of buffer, tiron concentration, reaction time and temperature were investigated. Under optimized conditions, the fluorescence quenching extent is proportional to the concentration of bismuth for Bi–tiron system at the range 0.13–2.09 μg mL{sup −1} and the detection limit is 0.05 μg mL{sup −1}. The proposed sensor presented good repeatability, evaluated in terms of relative standard deviation (R.S.D.=±0.498%) for 11 replicates. This sensitive, rapid and accurate method has been successfully applied to the determination of trace bismuth(III) in water and hair samples and certified reference materials. -- Highlights: • No previous paper report on use of fluorescence quenching for determination of Bi. • Fluorescence quenching of trion is a sensitive method for determination of Bi(III). • Under the optimum conditions the detection limit is very low (0.05 μg mL{sup −1}). • The procedure is simple and safe and has high tolerance limit to interferences.

  7. Dismantling and chemical characterization of spent Peltier thermoelectric devices for antimony, bismuth and tellurium recovery.

    Science.gov (United States)

    Balva, Maxime; Legeai, Sophie; Garoux, Laetitia; Leclerc, Nathalie; Meux, Eric

    2017-04-01

    Major uses of thermoelectricity concern refrigeration purposes, using Peltier devices, mainly composed of antimony, bismuth and tellurium. Antimony was identified as a critical raw material by EU and resources of bismuth and tellurium are not inexhaustible, so it is necessary to imagine the recycling of thermoelectric devices. That for, a complete characterization is needed, which is the aim of this work. Peltier devices were manually dismantled in three parts: the thermoelectric legs, the alumina plates on which remain the electrical contacts and the silicone paste used to connect the plates. The characterization was performed using five Peltier devices. It includes mass balances of the components, X-ray diffraction analysis of the thermoelectric legs and elemental analysis of each part of the device. It appears that alumina represents 45% of a Peltier device in weight. The electrical contacts are mainly composed of copper and tin, and the thermoelectric legs of bismuth, tellurium and antimony. Thermoelectric legs appear to be Se-doped Bi2Te3 and (Bi0,5Sb1,5)Te3 for n type and p type semiconductors, respectively. This work shows that Peltier devices can be considered as a copper ore and that thermoelectric legs contain high amounts of bismuth, tellurium and antimony compared to their traditional resources.

  8. Controlled growth of bismuth nanoparticles by electron beam irradiation in TEM

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Ho [College of Environment and Applied Chemistry, Kyung Hee University, Yongin 449-701 (Korea, Republic of); Choi, Young-Suk [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Kang, Kyongha [Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)]. E-mail: kkang@bnl.gov; Yang, Sung Ik [College of Environment and Applied Chemistry, Kyung Hee University, Yongin 449-701 (Korea, Republic of)]. E-mail: siyang@khu.ac.kr

    2007-01-16

    In situ nanometer-sized bismuth particles were synthesized by irradiation of the electron beam in the TEM. The size of the crystalline Bi nanoparticles could be controlled by adjusting the irradiation time of the electron beam. Characterization of TEM reveals that the Bi nanoparticles exist in rhombic structure, same as to bulk Bi.

  9. Controlled oxidative synthesis of Bi nanoparticles and emission centers in bismuth glass nanocomposites for photonic application

    Science.gov (United States)

    Singh, Shiv Prakash; Karmakar, Basudeb

    2011-09-01

    Here we demonstrate an oxidative process to control metallic bismuth (Bi 0) nanoparticles (NPs) creation in bismuth glass nanocomposites by using K 2S 2O 8 as oxidant and enhanced transparency of bismuth glasses. Formation of Bi 0 NPs has been monitored by their distinct surface plasmon resonance (SPR) band at 460 nm in the UV-visible absorption spectra. It is further confirmed by the transmission electron microscopy (TEM) images which disclose the formation of spherical Bi 0 NPs whereas the selected area electron diffraction (SAED) pattern reveals their crystalline rhombohedral phase. These glasses are found to exhibit visible and near infrared (NIR) luminescence bands at 630 and 843 nm respectively on excitation at 460 nm of the SPR band. It is realized that the luminescence center of bismuth species is an uncertain issue, however, it is reasonable to consider that the emission band at 630 nm is due to the combination of 2D 5/2 → 4S 3/2 of Bi 0 and 2P 3/2 (1) → 2P 1/2 of Bi 2+ transitions, and that of NIR emission band at 843 nm is attributed to the 2D 3/2 → 4S 3/2 of Bi 0 transition.

  10. The antimicrobial effects and metabolomic footprinting of carboxyl-capped bismuth nanoparticles against Helicobacter pylori.

    Science.gov (United States)

    Nazari, P; Dowlatabadi-Bazaz, R; Mofid, M R; Pourmand, M R; Daryani, N E; Faramarzi, M A; Sepehrizadeh, Z; Shahverdi, A R

    2014-01-01

    Organic salts of bismuth are currently used as antimicrobial agents against Helicobacter pylori. This study evaluated the antibacterial effect of elemental bismuth nanoparticles (Bi NPs) using a serial agar dilution method for the first time against different clinical isolates and a standard strain of H. pylori. The Bi NPs were biologically prepared and purified by a recently described method and subjected to further characterization by infrared spectroscopy and anti-H. pylori evaluation. Infrared spectroscopy results showed the presence of carboxyl functional groups on the surface of biogenic Bi NPs. These biogenic nanoparticles showed good antibacterial activity against all tested H. pylori strains. The resulting MICs varied between 60 and 100 μg/ml for clinical isolates of H. pylori and H. pylori (ATCC 26695). The antibacterial effect of bismuth ions was also tested against all test strains. The antimicrobial effect of Bi ions was lower than antimicrobial effect of bismuth in the form of elemental NPs. The effect of Bi NPs on metabolomic footprinting of H. pylori was further evaluated by (1)H NMR spectroscopy. Exposure of H. pylori to an inhibitory concentration of Bi NPs (100 μg/ml) led to release of some metabolites such as acetate, formic acid, glutamate, valine, glycine, and uracil from bacteria into their supernatant. These findings confirm that these nanoparticles interfere with Krebs cycle, nucleotide, and amino acid metabolism and shows anti-H. pylori activity.

  11. Microwave-assisted facile and rapid Friedel-Crafts benzoylation of arenes catalysed by bismuth trifluoromethanesulfonate

    DEFF Research Database (Denmark)

    Tran, Phoung Hoang; Hansen, Poul Erik; Pham, Thuy Than;

    2014-01-01

    The catalytic activity of metal triflates was investigated in Friedel–Crafts benzoylation under microwave irradiation. Friedel–Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is de...

  12. Effect of bismuth citrate, lactose, and organic acid on necrotic enteritis in broilers

    Science.gov (United States)

    Clostridium perfringens – associated necrotic enteritis causes significant losses and increased morbidity in poultry. The objective of this study was to evaluate the effect of bismuth citrate and acidifiers on the development of necrotic enteritis in broilers. The first study was a dose response t...

  13. 1.3 µm Raman-bismuth fiber amplifier pumped by semiconductor disk laser.

    Science.gov (United States)

    Chamorovskiy, A; Rautiainen, J; Rantamäki, A; Golant, K M; Okhotnikov, O G

    2011-03-28

    A hybrid Raman-bismuth fiber amplifier pumped in co-propagation configuration by a single 1.22 µm semiconductor disk laser is presented. The unique attribute of this dual-gain system is that both amplifiers require the pump source with the same wavelength because pump-Stokes spectral shift in 1.3 µm Raman amplifier and pump-gain bandwidth separation in 1.3 µm bismuth fiber amplifier have the same value. Residual pump power at the output of Raman amplifier in this scheme is efficiently consumed by bismuth-doped fiber thus increasing the overall conversion efficiency. The small-signal gain of 18 dB at 1.3 W of pump power has been achieved for hybrid scheme which is by 9 dB higher as compared with isolated Raman amplifier without bismuth fiber. Low noise performance of pump semiconductor disk laser with RIN of -150 dB/Hz combined with nearly diffraction-limited beam quality and Watt-level output powers allows for efficient core-pumping of a single-mode fiber amplifier systems and opens up new opportunities for amplification in O-band spectral range.

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

    Science.gov (United States)

    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. Preparation of Bismuth Oxide Photocatalyst and Its Application in White-light LEDs

    Directory of Open Access Journals (Sweden)

    Yen-Chang Chu

    2013-01-01

    Full Text Available Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates (x,y were (0.349, 0.393, and the correlated color temperature was 4991 K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of 66.2±0.60 ppmv of molecular formaldehyde gas can be decomposed in 120 mins.

  16. Thickness dependence of oxygen permeation through erbia-stabilized bismuth oxide-silver composites

    NARCIS (Netherlands)

    Chen, C.S.; Kruidhof, H.; Bouwmeester, H.J.M.; Verweij, H.; Burggraaf, A.J.

    1997-01-01

    Oxygen permeation measurements were performed on erbia-stabilized bismuth oxide-silver (40 v/o) composite membranes in the range of thickness of 1.60–0.23 mm and temperature of 850–650 °C. Air was fed at one side of the membranes while permeated oxygen on the other side was swept away with helium. A

  17. Bismuth oxide based ceramics with improved electrical and mechanical properties: Part II. Structural and mechanical properties

    NARCIS (Netherlands)

    Kruidhof, H.; Seshan, K.; Velde, van de G.M.H.; Vries, de K.J.; Burggraaf, A.J.

    1988-01-01

    Coprecipitation as a method of preparation for bismuth oxides based ceramics yields relatively strong and machineable materials in comparison with the solid state reaction. Compositions within the system (1−x)Bi2O3|xEr2O3 containing up to twenty five mole percent of erbium oxide show a slow transiti

  18. Dynamic spatial structure of spontaneous beams in photorefractive bismuth sillicon oxide

    DEFF Research Database (Denmark)

    Buchhave, Preben; Lyuksyutov, S.; Vasnetsov, M.

    1996-01-01

    We report the domain structure of spontaneously occurring beams (subharmonics) in photorefractive bismuth silicon oxide with an applied electric field from 1 to 6 kV/cm and a running grating. The subharmonic beams are generated in a pattern of domains that evolve dynamically as they move through...

  19. Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator.

    Science.gov (United States)

    Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrei V

    2014-11-17

    We propose new designs of plasmonic modulators, which can be used for dynamic signal switching in photonic integrated circuits. We study performance of a plasmonic waveguide modulator with bismuth ferrite as a tunable material. The bismuth ferrite core is sandwiched between metal plates (metal-insulator-metal configuration), which also serve as electrodes. The core changes its refractive index by means of partial in-plane to out-of-plane reorientation of ferroelectric domains in bismuth ferrite under applied voltage. As a result, guided modes change their propagation constant and absorption coefficient, allowing light modulation in both phase and amplitude control schemes. Due to high field confinement between the metal layers, existence of mode cut-offs for certain values of the core thickness, and near-zero material losses in bismuth ferrite, efficient modulation performance is achieved. For the phase control scheme, the π phase shift is provided by a 0.8-μm long device with propagation losses 0.29 dB/μm. For the amplitude control scheme, up to 38 dB/μm extinction ratio with 1.2 dB/μm propagation loss is predicted.

  20. 40 CFR 471.10 - Applicability; description of the lead-tin-bismuth forming subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the lead-tin-bismuth forming subcategory. 471.10 Section 471.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS FORMING AND METAL...

  1. Response of Ag Thick Film Microstripline due to Superstrate Strontium Substituted Bismuth Manganites

    Directory of Open Access Journals (Sweden)

    S.N. Mathad

    2014-06-01

    Full Text Available The purpose of this paper is to describe the use of strontium-substituted bismuth manganites bulk ceramic superstrate on Ag thick film microstripline, to modify its response and measure complex permittivity as a function of strontium. Bismuth strontium manganites (Bi1 − xSrxMnO3 have been synthesized by solid state sintering technique. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the Bi1 − xSrxMnO3 (0.20  x  0.50 overlay has been used to obtain the permittivity at microwave frequencies in X and Ku band range. Due to the overlay of Bismuth strontium manganites (BSM pellets a substantial increase in the effective dielectric constant was observed in X band more compared to Ku band. The in-touch overlay method provides ease loading and unloading. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the bismuth strontium manganites overlay has been used to obtain the permittivity.

  2. 75 FR 34360 - Listing of Color Additives Exempt From Certification; Bismuth Citrate; Confirmation of Effective...

    Science.gov (United States)

    2010-06-17

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 73 Listing of Color Additives Exempt From... March 26, 2010. The final rule amended the color additive regulations by increasing the permitted use level of bismuth citrate as a color additive in cosmetics intended for coloring hair on the scalp....

  3. A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots.

    Science.gov (United States)

    Tashkhourian, Javad; Absalan, Ghodratollah; Jafari, Marzieh; Zare, Saber

    2016-01-05

    A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of <10s. The results revealed that doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism. The sensor permitted determination of doxycycline in a concentration range of 1.9×10(-6)-6.1×10(-5)molL(-1) with a detection limit of 1.1×10(-7)molL(-1). The sensor was applied for determination of doxycycline in honey and human serum samples.

  4. Cuprous Iodide Catalyzed Synthesis of Diaryl Selenide and Telluride from Organoboronic Acids with Diphenyl Diselenide and Ditelluride

    Institute of Scientific and Technical Information of China (English)

    WANG,Lei; WANG,Min; YAN,Jin-Can; LI,Pin-Hua

    2004-01-01

    @@ Organoselenium and tellurium compounds have received much attention not only as synthetic reagents or intermediates in organic synthesis but also as promising donor molecules for conductive materials.[1] A number of synthetic methods have been reported to prepare organoselenium and tellurium derivatives. A convenient and general method to introduce a selenium or tellurium moiety into organic molecules is the reaction of a metal selenolate or tellurolate with appropriate electrophiles such as organic halides, acyl chlorides, epoxides, and α, β-enones.[2] However, it is difficult to synthesize the unsymmetrical diarylselenides and tellurides through the reaction of selenide anion with organic halides because of the less reactivity of aryl halides. To accomplish this purpose, the reaction (iodobenzene with phenylselenol)was generally carried out in the presence of catalysts, ligands and strong bases. But, the reaction needs longer time to accomplish and form the products in moderate yields.

  5. The effect of substrate rotation rate on physical properties of cadmium telluride films prepared by a glancing angle deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini Siyanaki, Fatemeh, E-mail: fatemeh.hosseini@gmail.com; Rezagholipour Dizaji, Hamid, E-mail: hrgholipour@semnan.ac.ir; Ehsani, Mohammad Hossein, E-mail: mhe_ehsani@yahoo.com; Khorramabadi, Shiva, E-mail: khorramabadi.sh@gmail.com

    2015-02-27

    Physical properties of cadmium telluride thin films, deposited on glass substrates by modified glancing angle deposition (GLAD) technique with various substrate rates of rotation, were investigated in this study. In contrast to obliquely columnar thin films fabricated by the conventional GLAD technique, in which higher columnar angle is coupled to higher degree of porosity, this study introduces obliquely deposited thin films which have packed columnar structures despite their highly tilted columns. Structural and optical properties and surface morphology of the CdTe thin films deposited by this technique were studied using X-ray diffraction, UV–visible spectroscopy and field emission scanning electron microscopy. - Highlights: • Glancing angle deposition technique was employed to prepare CdTe thin films. • The effect of substrate rate of rotation on optical properties was studied. • Highly tilted and packed columnar structure was fabricated. • A dramatic decline in refractive index in one of the specimens was observed.

  6. Thin-film cadmium telluride photovoltaic cells. Final subcontract report, 1 November 1992--1 January 1994

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.D.; Bohn, R.G. [Toledo Univ., OH (United States)

    1994-09-01

    This report describes work to develop and optimize radio-frequency (rf) sputtering for the deposition of thin films of cadmium telluride (CdTe) and related semiconductors for thin-film solar cells. Pulsed laser physical vapor deposition was also used for exploratory work on these materials, especially where alloying or doping are involved, and for the deposition of cadmium chloride layers. The sputtering work utilized a 2-in diameter planar magnetron sputter gun. The film growth rate by rf sputtering was studied as a function of substrate temperature, gas pressure, and rf power. Complete solar cells were fabricated on tin-oxide-coated soda-lime glass substrates. Currently, work is being done to improve the open-circuit voltage by varying the CdTe-based absorber layer, and to improve the short-circuit current by modifying the CdS window layer.

  7. OPTIMUM STOICHIOMETRY OF CADMIUM ZINC TELLURIDE THIN FILMS IN THE LIGHT OF OPTICAL, STRUCTURAL AND PHOTON GENERATED GAIN STUDIES

    Directory of Open Access Journals (Sweden)

    Dr. MONISHA CHAKRABORTY

    2011-05-01

    Full Text Available Cadmium Zinc Telluride (Cd1-xZnxTe is a potential material for high energy imaging devices. Proper methods are adopted in this work to fabricate large area device grade Cd1-xZnxTe thin films for ‘x’ varying from 0.0567 to 0.2210. Large work function Nickel (Ni is the contact points on these films. The fabricated films are subjected to optical characterization, structural characterization and photon generated gain studies. Properties of fabricated films are found to vary with ‘x’. Photon generated gains of Ni-Cd1-xZnxTe structures are obtained. The present paper dealt with the estimation of optimum ‘x’ in Cd1-xZnxTe thin films in the light of optical, structural and photon generated gain studies.

  8. Structural and Optical Properties of Sputtered Cadmium Telluride Thin Films Deposited on Flexible Substrates for Photovoltaic Applications.

    Science.gov (United States)

    Song, Woochang; Lee, Kiwon; Kim, Donguk; Lee, Jaehyeong

    2016-05-01

    Cadmium telluride (CdTe) is a photovoltaic technology based on the use of thin films of CdTe to absorb and convert sunlight into electricity. In this paper, polycrystalline CdTe thin films were deposited using radio frequency magnetron sputtering onto flexible substrates including polyimide and molybdenum foil. The structural and optical properties of the films grown at various sputtering pressures were investigated using X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and UV/Nis/NIR spectrophotometry. The sputtering pressure was found to have significant effects on the structural properties, including crystallinity, preferential orientation, and microstructure. Deterioration of the optical properties of CdTe thin films were observed at high sputtering pressure.

  9. Crystal Growth, Characterization and Fabrication of Cadmium Zinc Telluride-based Nuclear Detectors

    Science.gov (United States)

    Krishna, Ramesh M.

    In today's world, nuclear radiation is seeing more and more use by humanity as time goes on. Nuclear power plants are being built to supply humanity's energy needs, nuclear medical imaging is becoming more popular for diagnosing cancer and other diseases, and control of weapons-grade nuclear materials is becoming more and more important for national security. All of these needs require high-performance nuclear radiation detectors which can accurately measure the type and amount of radiation being used. However, most current radiation detection materials available commercially require extensive cooling, or simply do not function adequately for high-energy gamma-ray emitting nuclear materials such as uranium and plutonium. One of the most promising semiconductor materials being considered to create a convenient, field-deployable nuclear detector is cadmium zinc telluride (CdZnTe, or CZT). CZT is a ternary semiconductor compound which can detect high-energy gamma-rays at room temperature. It offers high resistivity (≥ 1010 O-cm), a high band gap (1.55 eV), and good electron transport properties, all of which are required for a nuclear radiation detector. However, one significant issue with CZT is that there is considerable difficulty in growing large, homogeneous, defect-free single crystals of CZT. This significantly increases the cost of producing CZT detectors, making CZT less than ideal for mass-production. Furthermore, CZT suffers from poor hole transport properties, which creates significant problems when using it as a high-energy gamma-ray detector. In this dissertation, a comprehensive investigation is undertaken using a successful growth method for CZT developed at the University of South Carolina. This method, called the solvent-growth technique, reduces the complexity required to grow detector-grade CZT single crystals. It utilizes a lower growth temperature than traditional growth methods by using Te as a solvent, while maintaining the advantages of

  10. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual subcontract report, 20 March 1993--19 March 1994

    Energy Technology Data Exchange (ETDEWEB)

    Trefny, J.U.; Furtak, T.E.; Williamson, D.L.; Kim, D. [Colorado School of Mines, Golden, CO (United States)

    1994-07-01

    This report describes the principal results of work performed during the second year of a 3-year program at the Colorado School of Mines (CSM). The work on transparent conducting oxides was carried out primarily by CSM students at NREL and is described in three publications listed in Appendix C. The high-quality ZnO produced from the work was incorporated into a copper indium diselenide cell that exhibited a world-record efficiency of 16.4%. Much of the time was devoted to the improvement of cadmium sulfide films deposited by chemical bath deposition methods and annealed with or without a cadmium chloride treatment. Progress was also made in the electrochemical deposition of cadmium telluride. High-quality films yielding CdS/CdTe/Au cells of greater than 10% efficiency are now being produced on a regular basis. We explored the use of zinc telluride back contacts to form an n-i-p cell structure as previously used by Ametek. We began small-angle x-ray scattering (SAXS) studies to characterize crystal structures, residual stresses, and microstructures of both CdTe and CdS. Large SAXS signals were observed in CdS, most likely because of scattering from gain boundaries. The signals observed to date from CdTe are much weaker, indicating a more homogeneous microstructure. We began to use the ADEPT modeling program, developed at Purdue University, to guide our understanding of the CdS/CdTe cell physics and the improvements that will most likely lead to significantly enhanced efficiencies.

  11. Charge carrier effective mass and concentration derived from combination of Seebeck coefficient and 125Te NMR measurements in complex tellurides

    Science.gov (United States)

    Levin, E. M.

    2016-06-01

    Thermoelectric materials utilize the Seebeck effect to convert heat to electrical energy. The Seebeck coefficient (thermopower), S , depends on the free (mobile) carrier concentration, n , and effective mass, m*, as S ˜m*/n2 /3 . The carrier concentration in tellurides can be derived from 125Te nuclear magnetic resonance (NMR) spin-lattice relaxation measurements. The NMR spin-lattice relaxation rate, 1 /T1 , depends on both n and m* as 1 /T1˜(m*)3/2n (within classical Maxwell-Boltzmann statistics) or as 1 /T1˜(m*)2n2 /3 (within quantum Fermi-Dirac statistics), which challenges the correct determination of the carrier concentration in some materials by NMR. Here it is shown that the combination of the Seebeck coefficient and 125Te NMR spin-lattice relaxation measurements in complex tellurides provides a unique opportunity to derive the carrier effective mass and then to calculate the carrier concentration. This approach was used to study A gxS bxG e50-2xT e50 , well-known GeTe-based high-efficiency tellurium-antimony-germanium-silver thermoelectric materials, where the replacement of Ge by [Ag+Sb] results in significant enhancement of the Seebeck coefficient. Values of both m* and n derived using this combination show that the enhancement of thermopower can be attributed primarily to an increase of the carrier effective mass and partially to a decrease of the carrier concentration when the [Ag+Sb] content increases.

  12. Bulk growth and surface characterization of epitaxy ready cadmium zinc telluride substrates for use in IR imaging applications

    Science.gov (United States)

    Flint, J. P.; Martinez, B.; Betz, T. E. M.; MacKenzie, J.; Kumar, F. J.; Bindley, G.

    2016-05-01

    Cadmium Zinc Telluride (CZT) is an important compound semiconductor material upon which Mercury Cadmium Telluride (MCT) layers are deposited epitaxially to form structures that are used in high performance detectors covering a wide infrared (IR) spectral band. The epitaxial growth of high quality MCT layers presents many technical challenges and a critical determinant of material performance is the quality of the underlying bulk CZT substrate. CZT itself is a difficult material to manufacture where traditional methods of bulk growth are complex and low yielding, which constrains the supply of commercially available substrates. In this work we report on the epitaxy-ready finishing of Travelling Heather Method (THM) grown Cd0.96Zn0.04Te substrates. The THM method is well established for the growth of high quality CZT crystals used in nuclear, X-ray and spectroscopic imaging applications and in this work we demonstrate the application of this technique to the growth of IR specification CZT substrates with areas of up to 5 cm x 5 cm square. We will discuss the advantages of the THM method over alternative methods of bulk CZT growth where the high yield and material uniformity advantages of this technique will be demonstrated. Chemo-mechanical polishing (CMP) of 4 cm x 4 cm CZT substrates reveals that III-V (InSb/GaSb) like levels of epitaxy-ready surface finishing may be obtained with modified process chemistries. Surface quality assessments will be made by various surface analytical and microscopy techniques from which the suitability of the material for subsequent assessment of quality by epitaxial growth will be ascertained.

  13. Synthesis of mercuric iodide and bismuth tri-iodide nanoparticles for heavy metal iodide films nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Fornaro, L.; Pereira, H.Bentos [Compound Semiconductors Group, CURE, Universidad de la Republica, Rocha (Uruguay); Aguiar, I.; Perez Barthaburu, M. [Compound Semiconductors Group, Facultad de Quimica, Univ. de la Republica, Montevideo (Uruguay)

    2011-12-15

    We synthesized mercuric iodide and bismuth tri-iodide nanoparticles by suspension in octadecene, from Hg(NO{sub 3}){sub 2}.H{sub 2}O and I{sub 2}, and from Bi(NO{sub 3}){sub 3}.5H{sub 2}O and I{sub 2}, respectively. The best synthesis conditions were 2 h at 70-80 C, followed by 10 min at 110 C for mercuric iodide nanoparticles, and 4 h at 80-110 C, followed by 10 min at 180-210 C for bismuth tri-iodide ones. Nanoparticles were then washed and centrifuged with ether repeatedly. Compounds identity was confirmed by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). We found shifts of the X-ray diffraction maxima for nanoparticles of both compounds. We characterized the nanoparticles by transmission (TEM) and scanning (SEM) electron microscopy. We obtained disk-like and squared mercuric iodide nanostructures, 80-140 nm and 100-125 nm in size respectively. We also obtained rounded and rod-like bismuth tri-iodide nanoparticles, 30-500 nm in size. Acetonitrile and isopropanol suspensions of mercuric iodide nanoparticles, and acetonitrile suspension of bismuth tri-iodide nanoparticles exhibited peak maxima shifts in their UV-Vis spectra. We synthesized for the first time mercuric iodide and bismuth tri-iodide nanoparticles by the suspension method, although we have not yet obtained uniform shape and size distributions. They offer interesting perspectives for crystalline film nucleation and for improving current applications of these materials, as well as for opening new ones. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Dose reduction in CT using bismuth shielding: measurements and Monte Carlo simulations.

    Science.gov (United States)

    Chang, Kyung-Hwan; Lee, Wonho; Choo, Dong-Myung; Lee, Choon-Sik; Kim, Youhyun

    2010-03-01

    In this research, using direct measurements and Monte Carlo calculations, the potential dose reduction achieved by bismuth shielding in computed tomography was evaluated. The patient dose was measured using an ionisation chamber in a polymethylmethacrylate (PMMA) phantom that had five measurement points at the centre and periphery. Simulations were performed using the MCNPX code. For both the bare and the bismuth-shielded phantom, the differences of dose values between experiment and simulation were within 9%. The dose reductions due to the bismuth shielding were 1.2-55% depending on the measurement points, X-ray tube voltage and the type of shielding. The amount of dose reduction was significant for the positions covered by the bismuth shielding (34 - 46% for head and 41 - 55% for body phantom on average) and negligible for other peripheral positions. The artefact on the reconstructed images were minimal when the distance between the shielding and the organs was >1 cm, and hence the shielding should be selectively located to protect critical organs such as the eye lens, thyroid and breast. The simulation results using the PMMA phantom was compared with those using a realistically voxelised phantom (KTMAN-2). For eye and breast, the simulation results using the PMMA and KTMAN-2 phantoms were similar with each other, while for thyroid the simulation results were different due to the discrepancy of locations and the sizes of the phantoms. The dose reductions achieved by bismuth and lead shielding were compared with each other and the results showed that the difference of the dose reductions achieved by the two materials was less than 2-3%.

  15. Hall Plateaus at magic angles in ultraquantum Bismuth

    Science.gov (United States)

    Benoît, Fauqué.

    2009-03-01

    The behaviour of a three-dimensional electron gas in the presence of a magnetic field strong enough to put all carriers in the first Landau level (i.e. beyond the quantum limit) is a longstanding question of theoretical condensed matter physics [1]. This issue has been recently explored by two high-field experiments on elemental semi-metal Bismuth. In a first study of transport coefficients (which are dominated by hole-like carriers), the Nernst coefficient presented three unexpected maxima that are concomitant with quasi-plateaux in the Hall coefficient [2]. In a second series of experiments, torque magnetometry (which mainly probes the three Dirac valley electron pockets) detected a field-induced phase transition [3]. The full understanding of the electron and hole behaviours above the quantum limit of pure Bi is therefore still under debate. In this talk, we will present our measurement of the Hall resistivity and torque magnetometry with magnetic field up to 31 T and rotating in the trigonal-bisectrix plane [4]. The Hall response is dominated by the hole pockets according to its sign as well as the period and the angular dependence of its quantum oscillations. In the vicinity of the quantum limit, it presents additional anomalies which are the fingerprints of the electron pockets. We found that for particular orientations of the magnetic field (namely ``magic angles''), the Hall response becomes field-independent within the experimental resolution around 20T. This drastic dependence of the plateaux on the field orientation provides strong constraints for theoretical scenarios. [4pt] [1] Bertrand I. Halperin, Japanese Journal of Applied Physics, 26, Supplement 26-3 (1987).[0pt] [2] Kamran Behnia, Luis Balicas, Yakov Kopelevich, Science, 317, 1729 (2008).[0pt] [3] Lu Li, J. G. Checkelsky, Y. S. Hor, C. Uher, A. F. Hebard, R. J. Cava, and N. P. Ong , Science, 321, 5888 (2008).[0pt] [4] Benoît Fauqu'e, Luis Balicas, Ilya Sheikin, Jean Paul Issi and Kamran Behnia

  16. Experimental study on the effects of bismuth subgallate on the inflammatory process and angiogenesis of the oral mucosa

    Directory of Open Access Journals (Sweden)

    Eduardo Vieira Couto

    2016-02-01

    Full Text Available ABSTRACT INTRODUCTION: Bismuth subgallate is a salt derived from heavy metal. The aim of this study was to evaluate the effect of this salt on some phases of healing. OBJECTIVES: To assess the effect of subgallate on mucosa and to evaluate the association between the use of bismuth subgallate and neogenesis of vessels in oral mucosal wounds. METHODS: This was a prospective and experimental study. This study used sixty rats, which were divided into control and experimental groups. The animals were submitted to a surgical procedure, which caused oral mucosal injury. A saline solution was applied on the wound of the control group, and in the experimental group, a solution of bismuth subgallate was administrated. RESULTS: The experimental group showed greater inflammatory reaction with increasing monomorphic proliferation. There was increased vessel proliferation in the control group. CONCLUSION: Bismuth subgallate had a negative influence on the healing process, delaying the rate of new vessel formation and optimal wound healing.

  17. Recent progress of bismuth-containing photocatalysts%含铋光催化材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    王伟华; 叶红齐; 覃涛; 刘宣业; 黄辉; 赵炜康; 朱坤杰

    2014-01-01

    Bismuth-containing photocatalysts can be used in many fields because of narrow band gap and ability of adsorbing visible light. In this paper , the latest research status and progress of bismuth-containing photocatalysts are reviewed. Bismuth oxide , halide bismuth oxide , bismuth titanate,bismuth tungstate,bismuth vanadate,bismuth molybdate and bismuth ferrite are introduced and the methods of improving photocatalytic performance are highlighted,including improvement of synthesis methods,photocatalysts doping and preparation of photocatalyst composites. Finally,the research directions of bismuth-containing photocatalysts are presented,aimed at improving overall performance and realizing industrial application of bismuth-containing photocatalysts , such as preparing multi-doped photocatalysts,multiple photocatalyst composites and supported catalysts.%含铋光催化材料因其能吸收可见光、催化活性高而具有广阔的应用前景。本文主要回顾了含铋光催化材料近年来的研究概况,详细介绍了铋氧化物、卤氧化铋及钛酸铋、钨酸铋、钒酸铋、钼酸铋、铁酸铋等光催化剂的结构、制备和光催化性能,重点对光催化性能的改进方法进行了综述,包括制备方法的改良、催化剂的掺杂改性及复合催化剂的制备等;最后针对进一步提高光催化剂整体性能、实现工业化应用两点,提出了未来可以利用多元元素掺杂、多元半导体复合进行改性和负载于某些载体制备整体催化剂进行改良的观点。

  18. 钒酸铋掺杂体系的研究进展%DEVELOPMENT OF DOPED BISMUTH VANADATE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    朱振峰; 张炼

    2012-01-01

    This paper mainly introduces development of bismuth vanadate doped with rare earth elements,transition elements,carbon group elements and other elements and put forward a development direction of bismuth vanadate materials in the future.%介绍了稀土元素、过渡元素、碳族元素和其它元素的钒酸铋掺杂体系,并对未来的发展方向做出展望。

  19. Bismuth Based Hybrid Perovskites A3Bi2 I9 (A: Methylammonium or Cesium) for Solar Cell Application.

    Science.gov (United States)

    Park, Byung-Wook; Philippe, Bertrand; Zhang, Xiaoliang; Rensmo, Håkan; Boschloo, Gerrit; Johansson, Erik M J

    2015-11-18

    Low-toxic bismuth-based perovskites are prepared for the possible replacement of lead perovskite in solar cells. The perovskites have a hexagonal crystalline phase and light absorption in the visible region. A power conversion efficiency of over 1% is obtained for a solar cell with Cs3 Bi2 I9 perovskite, and it is concluded that bismuth perovskites have very promising properties for further development in solar cells.

  20. EQCM Study of Influence of Anion Nature on Electrochemical Reduction of Bismuth Sulfide in Nickel Plating Solution

    OpenAIRE

    Loreta TAMAŠAUSKAITĖ-TAMAŠIŪNAITĖ; Leonas NARUŠKEVIČIUS; Žielienė, Albina; Birutė ŠIMKŪNAITĖ-STANYNIENĖ; Genovaitė VALIULIENĖ; Aloyzas SUDAVIČIUS

    2011-01-01

    The influence of anion nature on the reduction of bismuth sulfide film deposited on gold using the successive ionic layer adsorption and reaction method in solutions containing Ni2+ ions has been investigated by electrochemical quartz crystal microbalance combined with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been determined that the reduction of bismuth sulfide film in the nickel plating solution depends on the anion nature: larger cathodic current and mass changes (Dƒ...

  1. Pharmacokinetics and bioequivalence of ranitidine and bismuth derived from two compound preparations

    Institute of Scientific and Technical Information of China (English)

    Quan Zhou; Zou-Rong Ruan; Hong Yuan; Bo Jiang; Dong-Hang Xu

    2006-01-01

    AIM: To evaluate the bioequivalence of ranitidine and bismuth derived from two compound preparations.METHODS: The bioavailability was measured in 20healthy male Chinese volunteers following a single oral dose (equivalent to 200 mg of ranitidine and 220 mg of bismuth) of the test or reference products in the fasting state. Then blood samples were collected for 24 h.Plasma concentrations of ranitidine and bismuth were analyzed by high-performance liquid chromatography and inductively coupled plasma-mass spectrometry (ICPMS), respectively. The non-compartmental method was used for pharmacokinetic analysis. Log-transformed Cmax,AUC(0-t) and AUC(0-∞) were tested for bioequivalence using ANOVA and Schuirmann two-one sided t-test. Tmax was analyzed by Wilcoxon's test.RESULTS: Various pharmacokinetic parameters of ranitidine derived from the two compound preparations,including Cmax, AUC(0-t), AUC(0-∞), Tmax and T1/2, were nearly consistent with previous observations. These parameters derived from test and reference drug were as follows: Cmax(0.67 ± 0.21 vs 0.68 ± 0.22mg/L), AUC(0-t)(3.1 ± 0.6 vs 3.0 ± 0.7 mg/L per hour),AUC(0-∞)(3.3 ± 0.6 vs 3.2 ± 0.8 mg/L per hour),Tmax (2.3 ± 0.9 vs 2.1 ± 0.9 h) and T1/2 (2.8 ± 0.3 vs 3.1± 0.4 h). In addition, double-peak absorption profiles of ranitidine were found in some Chinese volunteers.For bismuth, those parameters derived from test and reference drug were as follows: Cmax (11.80 ± 7.36 vs 11.40 ± 6.55 μg/L),AUC(0-t) (46.65 ± 16.97 vs 47.03 ±21.49 μg/L per hour), Tmax (0.50 ± 0.20 vs 0.50 ± 0.20 h)and T1/2 (10.2 ± 2.3 vs 13.0 ± 6.9 h). Ninety percent of confidence intervals for the test/reference ratio of Cmax,AUC(0-t) and AUC(0-∞) derived from both ranitidine and bismuth were found within the bioequivalence acceptable range of 80%-125%. No significant difference was found in Tmax derived from both ranitidine and bismuth.CONCLUSION: The two compound preparations are bioequivalent and may be prescribed

  2. Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

    Science.gov (United States)

    Dellinger, Timothy Michael

    Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

  3. A bismuth activation counter for high sensitivity pulsed 14 MeV neutrons

    Science.gov (United States)

    Burns, E. J. T.; Thacher, P. D.; Hassig, G. J.; Decker, R. D.; Romero, J. A.; Barrett, K. P.

    2011-08-01

    We have built a fast neutron bismuth activation counter that measures activation counts from pulsed 14-MeV neutron generators for incident neutron fluences between 30 and 300 neutrons/cm2 at 15.2 cm (6 in.). The activation counter consists of a large bismuth germanate (BGO) detector surrounded by a bismuth metal shield in front of and concentric with the cylindrical detector housing. The 14 MeV neutrons activate the 2.6-millisecond (ms) isomer in the shield and the detector by the reaction 209Bi (n,2nγ) 208mBi. The use of millisecond isomers and activation counting times minimizes the background from other activated materials and the environment. In addition to activation, the bismuth metal shields against other outside radiation sources. We have tested the bismuth activation counter, simultaneously, with two data acquisition systems (DASs) and both give similar results. The two-dimensional (2D) DAS and three dimensional (3D) DAS both consist of pulse height analysis (PHA) systems that can be used to discriminate against gamma radiations below 300 keV photon energy, so that the detector can be used strictly as a counter. If the counting time is restricted to less than 25 ms after the neutron pulse, there are less than 10 counts of background for single pulse operation in all our operational environments tested so far. High-fluence neutron generator operations are restricted by large dead times and pulse height saturation. When we operate our 3D DAS PHA system in list mode acquisition (LIST), real-time corrections to dead time or live time can be made on the scale of 1 ms time windows or dwell times. The live time correction is consistent with nonparalyzable models for dead time of 1.0±0.2 μs for our 3D DAS and 1.5±0.3 μs for our 2D DAS dominated by our fixed time width analog to digital converters (ADCs). With the same solid angle, we have shown that the bismuth activation counter has a factor of 4 increase in sensitivity over our lead activation counter

  4. Three-Component One-Pot Synthesis of Novel Benzo[b]1,8-naphthyridines Catalyzed by Bismuth(III Chloride

    Directory of Open Access Journals (Sweden)

    Tangali R. Ravikumar Naik

    2008-01-01

    Full Text Available A novel and efficient three-component one-pot synthesis of benzo[b]1,8-naphthyridines by 2-amino-4-methylquinoline, aromatic aldehydes, and malononitrile was done. The reaction was catalyzed by an acidic Bismuth(III chloride, functionalized Bismuth(III chloride, at room temperature to give various benzo[b]1,8-naphthyridines in high yields. The Bismuth(III chloride is an environmentally friendly catalyst.

  5. Characterization, Leaching, and Filtration Testing for Bismuth Phosphate Sludge (Group 1) and Bismuth Phosphate Saltcake (Group 2) Actual Waste Sample Composites

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, Gregg J.; Buck, Edgar C.; Daniel, Richard C.; Draper, Kathryn; Edwards, Matthew K.; Fiskum, Sandra K.; Hallen, Richard T.; Jagoda, Lynette K.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Shimskey, Rick W.; Sinkov, Sergey I.; Snow, Lanee A.

    2009-02-19

    A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan.() The test program was subdivided into logical increments. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. The actual waste-testing program included homogenizing the samples by group, characterizing the solids and aqueous phases, and performing parametric leaching tests. Two of the eight defined groups—bismuth phosphate sludge (Group 1) and bismuth phosphate saltcake (Group 2)—are the subjects of this report. The Group 1 waste was anticipated to be high in phosphorus and was implicitly assumed to be present as BiPO4 (however, results presented here indicate that the phosphate in Group 1 is actually present as amorphous iron(III) phosphate). The Group 2 waste was also anticipated to be high in phosphorus, but because of the relatively low bismuth content and higher aluminum content, it was anticipated that the Group 2 waste would contain a mixture of gibbsite, sodium phosphate, and aluminum phosphate. Thus, the focus of the Group 1 testing was on determining the behavior of P removal during caustic leaching, and the focus of the Group 2 testing was on the removal of both P and Al. The waste-type definition, archived sample conditions, homogenization activities, characterization (physical, chemical, radioisotope, and crystal habit), and caustic leaching behavior as functions of time, temperature, and hydroxide concentration are discussed in this report. Testing was conducted according to TP-RPP-WTP-467.

  6. [L'application des radioisotopes a la chromatographie sur colonnes de celluloses substituees-IV L'analyse du mercure et du zinc dans le bismuth].

    Science.gov (United States)

    Muzzarelli, R A; Marcotrigiano, G

    1967-03-01

    The Chromatographic behaviour of nanogram amounts of bismuth has been studied by radioisotope techniques on cellobiose, cellulose and seven substituted celluloses. All celluloses in ethyl ether adsorb bismuth, provided that it is as nitrate, and that excess of nitric acid is avoided. Bismuth can be eluted with thiocyanate in ether-methanol or with hydrochloric acid in methanol, depending on the retention strength of the various functional groups of celluloses. A very simple method of separation of bismuth from mercury over a wide range of concentration is presented.

  7. Recovery of IR luminescence in photobleached bismuth-doped fibers by thermal annealing

    Science.gov (United States)

    Firstov, S. V.; Firstova, E. G.; Alyshev, S. V.; Khopin, V. F.; Riumkin, K. E.; Melkumov, M. A.; Guryanov, A. N.; Dianov, E. M.

    2016-08-01

    The effect of annealing temperature on the luminescent properties of bismuth-doped fibers bleached by 532 nm laser radiation was investigated. The photoluminescence (PL) measurements were performed in pristine and photobleached samples which were thermally annealed at various temperatures ranging from 100 to 900 °C and slowly cooled. We observed that the intensity of the PL band at 1700 nm in the photobleached fibers recovered its pre-bleached level. Moreover, it was shown that a significant increase of the PL level could be achieved using the special annealing regime. Thereby, we obtained the experimental evidence of a thermally activated recovery process of the PL intensity showing that photoinduced changes of PL in bismuth-doped fibers are completely reversible. The mechanism of the thermal recovery of the PL is discussed.

  8. Bismuth Basic Nitrate as a Novel Adsorbent for Azo Dye Removal

    Directory of Open Access Journals (Sweden)

    E. A. Abdullah

    2012-01-01

    Full Text Available Bismuth basic nitrate (BBN and its TiO2-Ag modified sorbent, PTBA were successfully synthesized via a precipitation method. The structural characteristics of prepared sorbents were determined through different analytical techniques. The potential use of prepared sorbents for organic compounds' removal was evaluated using Methyl Orange and Sunset Yellow dyes as model pollutants in aqueous solutions. The experimental results showed that the presence of TiO2 and Ag particles during the crystal growth of bismuth basic nitrate has an effect on the crystal structure, point of zero charge (pHpzc, pore volume and diameter. The lower binding energy of Ti 2p core level peak indicates the octahedral coordination of TiO2 particles on the PTBA surface. The alteration of hydrophilic-hydrophobic characteristics of sorbent's surface improves the adsorptive performance of the modified sorbent and provides an efficient route for organic contaminants' removal from aqueous solutions.

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

    Science.gov (United States)

    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.

  10. Mixed-layered bismuth--oxygen--iodine materials for capture and waste disposal of radioactive iodine

    Energy Technology Data Exchange (ETDEWEB)

    Krumhansl, James L; Nenoff, Tina M

    2015-01-06

    Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

  11. Graphite felt modified with bismuth nanoparticles as negative electrode in a vanadium redox flow battery.

    Science.gov (United States)

    Suárez, David J; González, Zoraida; Blanco, Clara; Granda, Marcos; Menéndez, Rosa; Santamaría, Ricardo

    2014-03-01

    A graphite felt decorated with bismuth nanoparticles was studied as negative electrode in a vanadium redox flow battery (VRFB). The results confirm the excellent electrochemical performance of the bismuth modified electrode in terms of the reversibility of the V(3+) /V(2+) redox reactions and its long-term cycling performance. Moreover a mechanism that explains the role that Bi nanoparticles play in the redox reactions in this negative half-cell is proposed. Bi nanoparticles favor the formation of BiHx , an intermediate that reduces V(3+) to V(2+) and, therefore, inhibits the competitive irreversible reaction of hydrogen formation (responsible for the commonly observed loss of Coulombic efficiency of VRFBs). Thus, the total charge consumed during the cathodic sweep in this electrode is used to reduce V(3+) to V(2+) , resulting in a highly reversible and efficient process.

  12. In situ transmission electron microscopy of solid-liquid phase transition of silica encapsulated bismuth nanoparticles

    Science.gov (United States)

    Hu, Jianjun; Hong, Yan; Muratore, Chris; Su, Ming; Voevodin, Andrey A.

    2011-09-01

    The solid-liquid phase transition of silica encapsulated bismuth nanoparticles was studied by in situ transmission electron microscopy (TEM). The nanoparticles were prepared by a two-step chemical synthesis process involving thermal decomposition of organometallic precursors for nucleating bismuth and a sol-gel process for growing silica. The microstructural and chemical analyses of the nanoparticles were performed using high-resolution TEM, Z-contrast imaging, focused ion beam milling, and X-ray energy dispersive spectroscopy. Solid-liquid-solid phase transitions of the nanoparticles were directly recorded by electron diffractions and TEM images. The silica encapsulation of the nanoparticles prevented agglomeration and allowed particles to preserve their original volume upon melting, which is desirable for applications of phase change nanoparticles with consistently repeatable thermal properties.

  13. Zero-dimensional nanostructured material with metallic bismuth nanoparticles: a new route for thermoelectrics

    Science.gov (United States)

    Benoit, Roland; Treguer, Mona; Saboungi, Marie-Louise

    2011-03-01

    The thermoelectric figure of merit ZT has so far not exceeded the value ZT=3 need to compete with mechanical energy conversion systems. However, theoretical work has shown that it is possible to reach values of ZT higher than this. One of the most promising routes is nanostructured materials, which offer the opportunity to tailor physical properties such as electrical and heat transport, due to the effects of electron filtering and phonon confinement. Dresselhaus et al. (ref.?) were among the first to show that 2D and 1D structures are capable of reaching ZT values higher than 2. The thermoelectric materials of current interest are in the form of nanotubes, nanodots and, more generally, superlattices composed of a matrix and nanoparticles. In our work we synthesize a periodic network of bismuth nanoparticles in a matrix of mesoporous Si O2 . We find that in this form bismuth transforms from a rhombohedral to a cubic structure, with improved filtering of electrons and phonons.

  14. A novel antifuse structure based on amorphous bismuth zinc niobate thin films

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Li Wei; Li Ping; Li Zuxiong; Fan Xue; Jiang Jing

    2012-01-01

    A novel antifuse structure with amorphous bismuth zinc niobate (a-BZN) dielectrics was proposed.The characteristics of the a-BZN antifuse were investigated.Programming direction of up to down was chosen to rupture the a-BZN antifuse.The breakdown voltage of the a-BZN antifuse was obtained at a magnitude of 6.56 V.A large off-state resistance of more than 1 GΩ for the a-BZN antifuse was demonstrated.The surface micrograph of the ruptured a-BZN antifuses was illustrated.Programming characteristics with the programming time of 0.46 ms and on-state properties with the average resistance value of 26.1 Ω of the a-BZN antifuse were exhibited.The difference of characteristics of the a-BZN antifuse from that of a cubic pyrochlore bismuth zinc niobate (cp-BZN) antifuse and gate oxide antifuse was compared and analyzed.

  15. Methylene blue photocatalysis in the presence of bismuth oxide under UV and solar light irradiation

    Directory of Open Access Journals (Sweden)

    Vanessa Rocha Liberatti

    2014-05-01

    Full Text Available Bismuth oxide (Bi2O3, an n-type semiconductor has been satisfactorily investigated for photocatalytic organic contaminant remediation. The Bi2O3 was prepared by solution combustion synthesis (SCS using as the oxidizing bismuth nitrate in acidic medium and urea as fuel. The influence of the type of synthesis on the photocatalytic properties of the oxide formed was investigated by XRD. From the diffractograms was verified that the materials obtained are predominantly of Bi2O3 crystals, it is possible to identify a sample with two crystalline phases, monoclinic (α-Bi2O3 and tetragonal (β-Bi2O3, and the other with only the monoclinic (α-Bi2O3. The two-phase oxide showed higher photocatalytic activity for discoloration of methylene blue under UV irradiation (60.59% and under sunlight (61.64% in 664 nm, followed kinetic law of pseudo-first order.

  16. The photorefractive characteristics of bismuth-oxide doped lithium niobate crystals

    Directory of Open Access Journals (Sweden)

    Dahuai Zheng

    2015-01-01

    Full Text Available Bismuth-doped lithium niobate (LN:Bi crystals were grown by Czochralski method and their optical damage resistance, photorefraction, absorption spectra, and defect energy levels were investigated. The experimental results indicate that the photorefractive properties of LN:Bi were enhanced as compared with congruent one, the photorefractive response time was greatly shortened, the photorefractive sensitivity was increased, and the diffraction efficiency of near-stoichiometric LN:Bi (SLN:Bi reached 31.72% and 49.08% at 532 nm and 488 nm laser, respectively (light intensity of 400 mW/cm2. An absorption peak at about 350 nm was observed in the absorption spectrum of LN:Bi. And the defect energy levels simulation indicates new defect levels appear in the forbidden gap of LN:Bi crystals. Therefore bismuth can act as photorefractive centers in LN crystals.

  17. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  18. Synthesis of Bismuth Ferrite Nanoparticles via a Wet Chemical Route at Low Temperature

    Directory of Open Access Journals (Sweden)

    Yongming Hu

    2011-01-01

    Full Text Available Nanoparticles (NPs of multiferroic bismuth ferrite (BiFeO3 with narrow size distributions were synthesized via a wet chemical route using bismuth nitrate and iron nitrate as starting materials and excess tartaric acid and citric acid as chelating agent, respectively, followed by thermal treatment. It was found that BiFeO3 NPs crystallized at ∼350∘C when using citric acid as chelating agent. Such crystallization temperature is much lower than that of conventional chemical process in which other types of chelating agent are used. BiFeO3 NPs with different sizes distributions show obvious ferromagnetic properties, and the magnetization is increased with reducing the particle size.

  19. Effect of Fe2O3 on the physical and structural properties of bismuth silicate glasses

    Science.gov (United States)

    Parmar, Rajesh; Kundu, R. S.; Punia, R.; Aghamkar, P.; Kishore, N.

    2013-06-01

    Iron containing bismuth silicate glasses with compositions 70SiO2ṡ(100-x)Bi2O3ṡxFe2O3 have been prepared using conventional melt-quenching method and their amorphous nature has been investigated using XRD. Density has been measured using Archimedes' principle and molar volume (Vm) have also been estimated. With increase in Fe2O3 content, there is a decrease in density and molar volume of the glass samples. The glass transition temperature (Tg) have been determined using Differential Scanning Calorimetry (DSC) and are observed to increase with increase in Fe2O3 content. In the present glass system bismuth and iron plays the role of network modifier and the symmetry of silicate network goes on increasing with Fe2O3 content and it modifies the physical and structural properties of these glasses.

  20. Synthesis and Electrochemical Sensing Toward Heavy Metals of Bunch-like Bismuth Nanostructures

    Directory of Open Access Journals (Sweden)

    Zhang Zhi

    2009-01-01

    Full Text Available Abstract Large-scale bunch-like bismuth (Bi nanostructures were the first time to be synthesized via two-step electrochemical deposition. The growth mechanism of the nanostructures was discussed. Such a designed bunch-like Bi electrode has high sensitivity to detect the heavy metal ions due to its unique three-dimensional structures and strong ability of adsorbing the heavy metal ions. The bunch-like Bi electrode’s detection of heavy metals was statically performed using anodic stripping voltammetry (ASV. The detection in the Pb(II concentration range of 2.5–50 μg/l was also performed. Based on the experimental results, this bunch-like Bi electrode can be considered as an interesting alternative to common mercury electrodes and bismuth film electrodes for possible use in electrochemical studies and electroanalytical applications.

  1. Gamma-ray shielding and structural properties of barium-bismuth-borosilicate glasses

    Science.gov (United States)

    Bootjomchai, Cherdsak; Laopaiboon, Jintana; Yenchai, Chadet; Laopaiboon, Raewat

    2012-07-01

    The attenuation coefficients of barium-bismuth-borosilicate glasses have been measured for gamma-ray photon energies of 662, 1173 and 1332 keV using a narrow beam transmission geometry. These coefficients were then used to obtain the values of mass attenuation coefficients, effective atomic number, effective electron density and mean free path. Good agreement has been observed between experimental and theoretical values of these parameters. From the obtained results it is reported here that from the barium-bismuth-borosilicate glasses are better shields to gamma-radiations in comparison to the standard radiation shielding concretes from the shielding point of view. The molar volume, FTIR and acoustic investigations have been used to study the structural properties of the prepared glass system. The obtained results reveal that the formation of non-bridging oxygens occurs at higher concentration of Bi2O3.

  2. Compatibility tests on steels in molten lead and lead-bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, C. E-mail: concetta@netbra.brasimone.enea.it; Benamati, G.; Martini, C.; Palombarini, G

    2001-07-01

    The compatibility of steels with liquid lead and liquid lead-bismuth is a critical issue for the development of accelerator-driven system (ADS). In this work the results of a set of preliminary tests carried out in stagnant molten lead at 737 K and in lead-bismuth at 573, 673 and 749 K are summarised. The tests were conducted for 700, 1200, 1500 and 5000 h. Three steels were tested: two martensitic steels (mod. F82H and MANET II) and one austenitic steel (AISI 316L). The martensitic steels underwent oxidation phenomena at the higher testing temperature, due to oxygen dissolved in the melts. At a lower test temperature (573 K) and higher exposure time (5000 h) the oxidation rate of the martensitic steel seems to be lower and the developed oxide layer protective against liquid metal corrosion. The austenitic steel, in turn, exhibited an acceptable resistance to corrosion-oxidation under the test conditions.

  3. Using polycrystalline bismuth filter in an ultracold neutron source with superfluid helium

    Science.gov (United States)

    Serebrov, A. P.; Lyamkin, V. A.; Runov, V. V.; Ivanov, S. A.; Onegin, M. S.; Fomin, A. K.

    2015-10-01

    Placing polycrystalline bismuth filter in front of an ultracold neutron (UCN) source with superfluid helium at 1 K is shown to be effective. The use of this filter ensures a 30-fold decrease (down to 0.5 W) in the level of heat load in the UCN source, while reducing by 30% the flux of neutrons with 9-Å wavelength (which are converted into UCNs). The phenomenon of small-angle scattering on polycrystalline bismuth has been studied and shown to be insignificant. Cooling of the filter to liquid nitrogen temperature increases the transmission of 9-Å neutrons by only 8%; hence, creation of this cooling system is inexpedient. A project of a technological complex designed for the UCN source at the PIK reactor is presented, which ensures the removal of 1-W heat load from the UCN source with superfluid helium at a 1-K temperature level.

  4. Quantum Interference of Surface States in Bismuth Nanowires in Transverse Magnetic Fields

    Science.gov (United States)

    Konopko, L. A.; Huber, T. E.; Nikolaeva, A. A.; Burceacov, L. A.

    2013-06-01

    We report the results of studies of the magnetoresistance (MR) and electric field effect (EFE) of single-crystal Bi nanowires with diameter dMurakami, bismuth bilayers can exhibit the quantum spin Hall effect. A Bi crystal can be viewed as a stacking of bilayers with a honeycomblike lattice structure along the [111] direction. An interpretation of transverse MR oscillations with using this theory is presented.

  5. A kinetic study of jack-bean urease denaturation by a new dithiocarbamate bismuth compound

    Science.gov (United States)

    Menezes, D. C.; Borges, E.; Torres, M. F.; Braga, J. P.

    2012-10-01

    A kinetic study concerning enzymatic inhibitory effect of a new bismuth dithiocarbamate complex on jack-bean urease is reported. A neural network approach is used to solve the ill-posed inverse problem arising from numerical treatment of the subject. A reaction mechanism for the urease denaturation process is proposed and the rate constants, relaxation time constants, equilibrium constants, activation Gibbs free energies for each reaction step and Gibbs free energies for the transition species are determined.

  6. Bismuth Infusion of ABS Enables Additive Manufacturing of Complex Radiological Phantoms and Shielding Equipment.

    Science.gov (United States)

    Ceh, Justin; Youd, Tom; Mastrovich, Zach; Peterson, Cody; Khan, Sarah; Sasser, Todd A; Sander, Ian M; Doney, Justin; Turner, Clark; Leevy, W Matthew

    2017-02-24

    Radiopacity is a critical property of materials that are used for a range of radiological applications, including the development of phantom devices that emulate the radiodensity of native tissues and the production of protective equipment for personnel handling radioactive materials. Three-dimensional (3D) printing is a fabrication platform that is well suited to creating complex anatomical replicas or custom labware to accomplish these radiological purposes. We created and tested multiple ABS (Acrylonitrile butadiene styrene) filaments infused with varied concentrations of bismuth (1.2-2.7 g/cm³), a radiopaque metal that is compatible with plastic infusion, to address the poor gamma radiation attenuation of many mainstream 3D printing materials. X-ray computed tomography (CT) experiments of these filaments indicated that a density of 1.2 g/cm³ of bismuth-infused ABS emulates bone radiopacity during X-ray CT imaging on preclinical and clinical scanners. ABS-bismuth filaments along with ABS were 3D printed to create an embedded human nasocranial anatomical phantom that mimicked radiological properties of native bone and soft tissue. Increasing the bismuth content in the filaments to 2.7 g/cm³ created a stable material that could attenuate 50% of (99m)Technetium gamma emission when printed with a 2.0 mm wall thickness. A shielded test tube rack was printed to attenuate source radiation as a protective measure for lab personnel. We demonstrated the utility of novel filaments to serve multiple radiological purposes, including the creation of anthropomorphic phantoms and safety labware, by tuning the level of radiation attenuation through material customization.

  7. Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead

    Science.gov (United States)

    Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim; Senin, H. B.

    2007-05-01

    Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg.

  8. Compositional dependence of optical band gap and refractive index in lead and bismuth borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mallur, Saisudha B.; Czarnecki, Tyler; Adhikari, Ashish; Babu, Panakkattu K.

    2015-08-15

    Highlights: • Refractive indices increase with increasing PbO/Bi{sub 2}O{sub 3} content. • Optical band gap arises due to direct forbidden transition. • Optical band gaps decrease with increasing PbO/Bi{sub 2}O{sub 3} content. • New empirical relation between the optical band gap and the refractive index. - Abstract: We prepared a series of lead and bismuth borate glasses by varying PbO/Bi{sub 2}O{sub 3} content and studied refractive index and optical band gap as a function of glass composition. Refractive indices were measured very accurately using a Brewster’s angle set up while the optical band gaps were determined by analyzing the optical absorption edge using the Mott–Davis model. Using the Lorentz–Lorentz method and the effective medium theory, we calculated the refractive indices and then compared them with the measured values. Bismuth borate glasses show better agreement between the calculated values of the refractive index and experimental values. We used a differential method based on Mott–Davis model to obtain the type of transition and optical band gap (E{sub opt}) which in turn was compared with the value of E{sub opt} obtained using the extinction coefficient. Our analysis shows that in both lead and bismuth borate glasses, the optical band gap arises due to direct forbidden transition. With increasing PbO/Bi{sub 2}O{sub 3} content, the absorption edge shifts toward longer wavelengths and the optical band gap decreases. This behavior can be explained in terms of changes to the Pb−O/Bi−O chemical bonds with glass composition. We obtained a new empirical relation between the optical band gap and the refractive index which can be used to accurately determine the electronic oxide polarizability in lead and bismuth oxide glasses.

  9. Influence of inherent strain on the curie temperature of rare earth ion-doped bismuth vanadate

    OpenAIRE

    Sooryanarayana, K; Row, TNG; R. Somashekar; Varma, KBR

    1998-01-01

    X-ray line broadening is found to be an effective parameter to estimate the strain associated with rare earth ion (Gd3+)-doped polycrystalline bismuth vanadate(Bi2VO5.5). The strain increases with increasing Gd3+ concentration. It is anisotropic and found to be maximum in (111) plane. The Curie temperature which is known to decrease with increase in the rare earth ion concentration in these compounds is correlated with increase in strain.

  10. Photoelectroactivity of Bismuth Vanadate Prepared by Combustion Synthesis: Effect of Different Fuels and Surfactants

    OpenAIRE

    Afonso,Renata; Serafim, Jessica A.; Lucilha,Adriana C.; Marcelo R. Silva; Lepre, Luiz F.; Ando, Romulo A.; Dall'Antonia,Luiz H.

    2014-01-01

    The bismuth vanadate (BiVO4) is a semiconductor that has attracted much attention due to the photocatalytic efficiency in the visible light region. The objective of this work was to synthesize monoclinic BiVO4 by solution combustion synthesis, with different surfactants and fuels and apply it as photoelectrodes. The characterization by infrared spectroscopy and Raman spectroscopy showed that all samples showed characteristic bands of the monoclinic structure BiVO4. The samples synthesized wit...

  11. Mechanistic insights into chemical and photochemical transformations of bismuth vanadate photoanodes

    OpenAIRE

    Toma, Francesca M.; Cooper, Jason K.; Kunzelmann, Viktoria; McDowell, Matthew T.; Yu, Jie; Larson, David M.; Borys, Nicholas J.; Abelyan, Christine; Beeman, Jeffrey W.; Yu, Kin Man; Yang, Jinhui; Chen, Le; Shaner, Matthew R.; Spurgeon, Joshua; Houle, Frances A.

    2016-01-01

    Artificial photosynthesis relies on the availability of semiconductors that are chemically stable and can efficiently capture solar energy. Although metal oxide semiconductors have been investigated for their promise to resist oxidative attack, materials in this class can suffer from chemical and photochemical instability. Here we present a methodology for evaluating corrosion mechanisms and apply it to bismuth vanadate, a state-of-the-art photoanode. Analysis of changing morphology and compo...

  12. Improving the photoactivity of bismuth vanadate thin film photoanodes through doping and surface modification strategies

    OpenAIRE

    Quiñonero, Javier; Lana Villarreal, Teresa; Gómez, Roberto

    2016-01-01

    Currently, one of the most attractive and desirable ways to solve the energy challenge is harvesting energy directly from the sunlight through the so-called artificial photosynthesis. Among the ternary oxides based on earth–abundant metals, bismuth vanadate has recently emerged as a promising photoanode. Herein, BiVO4 thin film photoanodes have been successfully synthesized by a modified metal-organic precursor decomposition method, followed by an annealing treatment. In an attempt to improve...

  13. Dielectric, piezoelectric, and pyroelectric anisotropy in KCL- modified grain-oriented bismuth vanadate ceramics

    OpenAIRE

    Shantha, K; Varma, KBR

    1999-01-01

    The effect of the additive KCl, on the structural, microstructural, and polar properties of bismuth vanadate (BiV) ceramics is investigated. The scanning electron microscopic (SEM) studies reveal a remarkable modification in the microstructure and the occurrence of high grain-orientation (75%) on KCl addition. The energy dispersive x ray (EDX) analyses indicate the presence of chemically inhomogeneous distribution of KCl, with core-shell-like grain structure. The KCl-modified BiV samples exhi...

  14. Bismuth Infusion of ABS Enables Additive Manufacturing of Complex Radiological Phantoms and Shielding Equipment

    Directory of Open Access Journals (Sweden)

    Justin Ceh

    2017-02-01

    Full Text Available Radiopacity is a critical property of materials that are used for a range of radiological applications, including the development of phantom devices that emulate the radiodensity of native tissues and the production of protective equipment for personnel handling radioactive materials. Three-dimensional (3D printing is a fabrication platform that is well suited to creating complex anatomical replicas or custom labware to accomplish these radiological purposes. We created and tested multiple ABS (Acrylonitrile butadiene styrene filaments infused with varied concentrations of bismuth (1.2–2.7 g/cm3, a radiopaque metal that is compatible with plastic infusion, to address the poor gamma radiation attenuation of many mainstream 3D printing materials. X-ray computed tomography (CT experiments of these filaments indicated that a density of 1.2 g/cm3 of bismuth-infused ABS emulates bone radiopacity during X-ray CT imaging on preclinical and clinical scanners. ABS-bismuth filaments along with ABS were 3D printed to create an embedded human nasocranial anatomical phantom that mimicked radiological properties of native bone and soft tissue. Increasing the bismuth content in the filaments to 2.7 g/cm3 created a stable material that could attenuate 50% of 99mTechnetium gamma emission when printed with a 2.0 mm wall thickness. A shielded test tube rack was printed to attenuate source radiation as a protective measure for lab personnel. We demonstrated the utility of novel filaments to serve multiple radiological purposes, including the creation of anthropomorphic phantoms and safety labware, by tuning the level of radiation attenuation through material customization.

  15. STUDY ON THE DETERMINATION OF TRACE BISMUTH(Ⅲ) BY THIN-LAYER RESIN PHASE SPECTROPHOTOMETRY

    Institute of Scientific and Technical Information of China (English)

    YAN Yongsheng; LU Xiaohua; FU Chengguang

    2003-01-01

    In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anioncomplex [BiI-4] in a strong acidic environments. This anion complex can also exchanges with a weaker anions on the surface active site of anion exchange resin, so that a [R+] [BiI-4] solid phase binary associational system is produced. Owing to the solid system is a great many dispersive particulates, it can be pressed to a thin-layer by press tools of the so called "thin-layer resin phase"or "resin phase ", and using this solid association system spectrophotometry for the determination of trace metals. So it can increase the analytical sensitivity. This association system exhibits maximum absorbance at 460nm, and obeys Beer's law over the concentration range 0. 01ug/ml~1.20ug/ml of bismuthous(Ⅲ). It has a molar absorptivity of 7.1 ×105 [L/mol cm]. It indicated the resin phase spectrophotometry is a sensitive analytical method for trace bismuthous. It is 18 times higher than routine aqueous spectrophotometry. The relative standard deviations is 1.82% (n=6) for the measurements of 0. 5ug/ml Bi(Ⅲ). The detection limit of Bismuthous(Ⅲ) is 1.4 ×10-8mol/L. The method has applied to the analysis Bi(Ⅲ) in environmental water samples.

  16. Report - Melter Testing of New High Bismuth HLW Formulations VSL-13R2770-1

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A.; Pegg, I. L.; Kot, W. K.; Gan, H.; Matlack, K. S.

    2013-11-13

    The primary objective of the work described was to test two glasses formulated for a high bismuth waste stream on the DM100 melter system. Testing was designed to determine processing characteristics and production rates, assess the tendency for foaming, and confirm glass properties. The glass compositions tested were previously developed to maintain high waste loadings and processing rates while suppressing the foaming observed in previous tests

  17. Electroless deposition of bismuth on Si(111) wafer from hydrogen fluoride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Romann, T., E-mail: tavo.romann@ut.e [Institute of Chemistry, University of Tartu, 2 Jakobi Street, 51014 Tartu (Estonia); Anderson, E.; Kallip, S. [Institute of Chemistry, University of Tartu, 2 Jakobi Street, 51014 Tartu (Estonia); Maendar, H.; Matisen, L. [Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu (Estonia); Lust, E. [Institute of Chemistry, University of Tartu, 2 Jakobi Street, 51014 Tartu (Estonia)

    2010-05-03

    Thin Bi layers were deposited by simple immersion of silicon chip into diluted HF aqueous solution, containing bismuth(III) ions. Bi nanoparticles or continuous up to 300 nm thick Bi film can be grown on silicon by the variation of the temperature and deposition time. Prepared surfaces have been characterized by atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering, photoluminescence and resistivity measurement methods. It was found that thinner Bi layers have a yellowish colour.

  18. Analysis of the color alteration and radiopacity promoted by bismuth oxide in calcium silicate cement

    Directory of Open Access Journals (Sweden)

    Marina Angelica Marciano

    2013-07-01

    Full Text Available The aim of the study was to determine if the increase in radiopacity provided by bismuth oxide is related to the color alteration of calcium silicate-based cement. Calcium silicate cement (CSC was mixed with 0%, 15%, 20%, 30% and 50% of bismuth oxide (BO, determined by weight. Mineral trioxide aggregate (MTA was the control group. The radiopacity test was performed according to ISO 6876/2001. The color was evaluated using the CIE system. The assessments were performed after 24 hours, 7 and 30 days of setting time, using a spectrophotometer to obtain the ΔE, Δa, Δb and ΔL values. The statistical analyses were performed using the Kruskal-Wallis/Dunn and ANOVA/Tukey tests (p 3 mm equivalent of Al. The MTA group was statistically similar to the CSC / 30% BO group (p > 0.05. In regard to color, the increase of bismuth oxide resulted in a decrease in the ΔE value of the calcium silicate cement. The CSC group presented statistically higher ΔE values than the CSC / 50% BO group (p < 0.05. The comparison between 24 hours and 7 days showed higher ΔE for the MTA group, with statistical differences for the CSC / 15% BO and CSC / 50% BO groups (p < 0.05. After 30 days, CSC showed statistically higher ΔE values than CSC / 30% BO and CSC / 50% BO (p < 0.05. In conclusion, the increase in radiopacity provided by bismuth oxide has no relation to the color alteration of calcium silicate-based cements.

  19. Single crystals of bismuth silicon oxide grown by the Czochralski technique and their characterisation

    Directory of Open Access Journals (Sweden)

    ANDREJA VALCIC

    1999-09-01

    Full Text Available Single crystals of Bi12SiO20 were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. X-Ray measurements were performed on powdered samples to obtain the lattice parameters. The optical properties of the bismuth silicon oxide single crystals were investigated. The obtained results are discussed and compared with published data.

  20. Effect of bismuth addition to the triple therapy of Helicobacter pylori eradication

    Directory of Open Access Journals (Sweden)

    Ezel Taşdemir

    2012-03-01

    Full Text Available Objective: Success rates of amoxicillin, clarithromycin, and proton-pump inhibitor therapy in the Helicobacter pylori (Hp eradication have been decreasing. The aim of this study was to investigate the impact of bismuth subcitrate addition to triple therapy.Materials and methods: 148 patients diagnosed Hp infection with both histology and Hp stool antigen (HpSA tests were examined retrospectively. The patients were divided into 3 groups according to the eradication therapy. The first group received triple therapy with claritromycine 2x 500 mg, amoxicilline 2x1 g and PPI 2x1 for 14 days (n=40. The second group had bismuth subcitrate 4x120 mg with triple therapy for 14 days (n=73. The third group received 14 days pretreatment with bismuth subcitrate 4x1 together with PPI 2x1 then had triple therapy for 14 days (n=35. (14C urea breath and HpSA tests were used to detect posttreatment H.pylori status.Results: There were no statistical difference between the groups in terms of gender and age (p > 0.05. In group one 12 patients, in group two 20 patients and in group three 10 patients were identified as Hp positive after treatment. Eradication rates were 70% for group one, 72.6% for group two and 71.4% for group three respectively. There was no statistical difference between the groups in terms of eradication rates of treatment (p > 0.05.Conclusions: The addition of bismuth to conventional triple therapy did not affect treatment success rates.

  1. Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

    Science.gov (United States)

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present inBi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely 241Am and 137Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

  2. Bismuth Modified Porous Silica Preparation, Characterization and Photocatalytic Activity Evaluation for Degradation of Isoproturon

    Institute of Scientific and Technical Information of China (English)

    Anil Kumar Reddy Police; Srinivas Basavaraju; Durga Kumari Valluri; Subrahmanyam Machiraju

    2013-01-01

    Porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Sio5 species containing surface.The as-prepared materials have been characterized by X-ray diffraction spectroscopy (XRD),X-ray photoelectron spectroscopy (XPS),UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS),scanning electron microscopy (SEM),energy dispersive analysis of X-ray (EDAX),transmission electron microscopy (TEM),Fourier transform infrared spectroscopy (FTIR) and N2 adsorption/desorption techniques.EDAX analysis confirms the penetration of bismuth ions into the framework of silica to form Bi2Sio5,which is substantiated by XRD.The UV-Vis DRS shows that the catalysts are optically active and XPS confirms the inclusion of bismuth into the framework of silica.FTIR spectra illustrate the formation of Bi-O-Si linkages in the porous silica framework.SEM and TEM show the spherical morphology,whereas N2 adsorption/desorption study confirms the porosity of the prepared materials.The photocatalytic activity of the material is evaluated for the degradation of isoproturon herbicide and it is found that the material is active as compared to the commercial P-25 Degussa Tio2.

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

    Energy Technology Data Exchange (ETDEWEB)

    Waghmare, Shivaji D.; Jadhav, Vijaykumar V.; Gore, Shaym K. [Center for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, Maharashtra (India); Yoon, Seog-Joon; Ambade, Swapnil B. [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Seoul 133-1791 (Korea, Republic of); Lokhande, B.J. [Department of Physics, Solapur University, Solapur (India); Mane, Rajaram S., E-mail: rsmane_2000@yahoo.com [Center for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, Maharashtra (India); Han, Sung-Hwan, E-mail: shhan@hanyang.ac.kr [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Seoul 133-1791 (Korea, Republic of)

    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.

  4. Alkali-metal-supported bismuth polyhedra-principles and theoretical studies.

    Science.gov (United States)

    Monakhov, Kirill Yu; Linti, Gerald; Wolters, Lando P; Bickelhaupt, F Matthias

    2011-06-20

    We have quantum chemically investigated the structure, stability, and bonding mechanism in highly aggregated alkali-metal salts of bismuthanediide anions [RBi](2-) using relativistic density functional theory (DFT, at ZORA-BP86/TZ2P) in combination with a quantitative energy decomposition analysis (EDA). Our model systems are alkali-metal-supported bismuth polyhedra [(RBi)(n)M(2n-4)](4-) with unique interpenetrating shells of a bismuth polyhedron and an alkali-metal superpolyhedron. Furthermore, we have analyzed the trianionic inclusion complexes [M'@{(RBi)(n)M(2n-4)}](3-) involving an additional endohedral alkali-metal ion M'. The main objective is to assist the further development of synthetic approaches toward this class of compounds. Our analyses led to electron-counting rules relating, for example, the number of bonding orbitals (N(bond)) of the cage molecules [(RBi)(n)M(2n+Q)](Q) to the number of bismuth atoms (n(Bi)), alkali-metal atoms (n(M)), and net charge Q as N(bond) = n(Bi) + n(M) - Q (R = one-electron donor ligand; M = alkali metal; n = 4-12; Q = -4, -6, -8). Finally, on the basis of our findings, we predict the next members in the 5-fold symmetrical row of alkali-metallobismaspheres with a macroicosahedral arrangement.

  5. Efficient photoelectrochemical hydrogen production from bismuth vanadate-decorated tungsten trioxide helix nanostructures

    Science.gov (United States)

    Shi, Xinjian; Choi, Il Yong; Zhang, Kan; Kwon, Jeong; Kim, Dong Yeong; Lee, Ja Kyung; Oh, Sang Ho; Kim, Jong Kyu; Park, Jong Hyeok

    2014-09-01

    Tungsten trioxide/bismuth vanadate heterojunction is one of the best pairs for solar water splitting, but its photocurrent densities are insufficient. Here we investigate the advantages of using helical nanostructures in photoelectrochemical solar water splitting. A helical tungsten trioxide array is fabricated on a fluorine-doped tin oxide substrate, followed by subsequent coating with bismuth vanadate/catalyst. A maximum photocurrent density of ~5.35±0.15 mA cm-2 is achieved at 1.23 V versus the reversible hydrogen electrode, and related hydrogen and oxygen evolution is also observed from this heterojunction. Theoretical simulations and analyses are performed to verify the advantages of this helical structure. The combination of effective light scattering, improved charge separation and transportation, and an enlarged contact surface area with electrolytes due to the use of the bismuth vanadate-decorated tungsten trioxide helical nanostructures leads to the highest reported photocurrent density to date at 1.23 V versus the reversible hydrogen electrode, to the best of our knowledge.

  6. Simultaneous enhancements in photon absorption and charge transport of bismuth vanadate photoanodes for solar water splitting

    Science.gov (United States)

    Kim, Tae Woo; Ping, Yuan; Galli, Giulia A.; Choi, Kyoung-Shin

    2015-10-01

    n-Type bismuth vanadate has been identified as one of the most promising photoanodes for use in a water-splitting photoelectrochemical cell. The major limitation of BiVO4 is its relatively wide bandgap (~2.5 eV), which fundamentally limits its solar-to-hydrogen conversion efficiency. Here we show that annealing nanoporous bismuth vanadate electrodes at 350 °C under nitrogen flow can result in nitrogen doping and generation of oxygen vacancies. This gentle nitrogen treatment not only effectively reduces the bandgap by ~0.2 eV but also increases the majority carrier density and mobility, enhancing electron-hole separation. The effect of nitrogen incorporation and oxygen vacancies on the electronic band structure and charge transport of bismuth vanadate are systematically elucidated by ab initio calculations. Owing to simultaneous enhancements in photon absorption and charge transport, the applied bias photon-to-current efficiency of nitrogen-treated BiVO4 for solar water splitting exceeds 2%, a record for a single oxide photon absorber, to the best of our knowledge.

  7. The synthesis of bismuth vanadate powders and their photocatalytic properties under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shen Yue [Institute of Material Physical Chemistry, Huaqiao University, Key Laboratory for Functional Materials of Fujian Higher Education, Quanzhou, Fujian 362021 (China); Huang Miaoliang, E-mail: huangml@hqu.edu.c [Institute of Material Physical Chemistry, Huaqiao University, Key Laboratory for Functional Materials of Fujian Higher Education, Quanzhou, Fujian 362021 (China); Huang Yi; Lin Jianming; Wu Jihuai [Institute of Material Physical Chemistry, Huaqiao University, Key Laboratory for Functional Materials of Fujian Higher Education, Quanzhou, Fujian 362021 (China)

    2010-04-30

    Bismuth vanadate powders were prepared by hydrothermal method with NaVO{sub 3} and Bi(NO{sub 3}){sub 3} as starting materials and with Na{sub 2}CO{sub 3} to adjust pH, and characterized by XRD, SEM, EDS and surface area analyzer. The results showed that the phase formation of bismuth vanadate depended on the adding amount of Na{sub 2}CO{sub 3}. The bismuth vanadate samples existed as monoclinic BiVO{sub 4} by adding 0.019 and 0.038 mol of Na{sub 2}CO{sub 3} with corresponding pH value of 0.2 and 5.8, respectively, and as Bi{sub 4}V{sub 2}O{sub 11} by adding 0.057 mol of Na{sub 2}CO{sub 3} with corresponding pH value of 9.7. The photocatalytic activities of the samples were evaluated by the decolorization of methylene blue (MB) under visible light irradiation. The sample with monoclinic form obtained by adding 0.019 mol of Na{sub 2}CO{sub 3} had the highest photocatalytic activity, the decolorization rate of MB reached to 96.4% under visible light irradiation in 200 min and the reaction rate constant was 0.015 min{sup -1}.

  8. Synthesis, crystal growth and mechanical properties of Bismuth Silicon Oxide (BSO) single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Riscob, B. [CSIR – National Physical Laboratory, Crystal Growth and X-ray Analysis, New Delhi 110 012 (India); Institute for Plasma Research, Bhat, Gandhinagar 382428, Gujarat (India); Shkir, Mohd. [CSIR – National Physical Laboratory, Crystal Growth and X-ray Analysis, New Delhi 110 012 (India); Ganesh, V. [Department of Physics, Kakatiya University, Warangal 506 009 (India); Vijayan, N.; Maurya, K.K. [CSIR – National Physical Laboratory, Crystal Growth and X-ray Analysis, New Delhi 110 012 (India); Kishan Rao, K. [Department of Physics, Kakatiya University, Warangal 506 009 (India); Bhagavannarayana, G., E-mail: bhagavan@mail.nplindia.ernet.in [CSIR – National Physical Laboratory, Crystal Growth and X-ray Analysis, New Delhi 110 012 (India)

    2014-03-05

    Highlights: • Synthesis of Bismuth Silicon Oxide (BSO). • Single crystal growth of BSO by Czochralski (Cz) method. • Complete mechanical analysis by device fabrication point of view. • Theoretical and experimental calculations of mechanical properties. -- Abstract: Bismuth Silicon Oxide (BSO) is an efficient material for piezo-electric and electro-optic applications. In this article, growth of BSO single crystal by high temperature Czochralski melt growth technique and its detailed mechanical characterization by Vickers microhardness, fracture toughness, crack propagation, brittleness index and yield strength have been reported. The raw material was synthesized by solid state reaction using the stoichiometric ratio of high purity bismuth tri-oxide and silicon di-oxide. The synthesized material was charged in the platinum crucible and then melted. The required rotation and pulling rate was optimized for BSO single crystal growth and good quality single crystal has been harvested after a time span of 5 days. Powder X-ray diffraction analysis confirms the parent crystallization phase of BSO. The experimentally studied mechanical behavior of the crystal is explained using various theoretical models. The anisotropic nature of the crystals is studied using Knoop indentation technique.

  9. Underpotential Deposition Study and Determination of Bismuth on Gold Electrode by Using Voltammetry

    Institute of Scientific and Technical Information of China (English)

    DU,Yong-Ling(杜永令); WANG,Chun-Ming(王春明)

    2002-01-01

    The cyclic voltammetry (CV) and the semidifferential anodic stripping voltanmetry (SdASV) were used for investigation of bismuth(Ⅲ) underpotential deposition (UPD) on gold electrode. Based on the excellent electrochemical properties of Au/Bi UPD system, a new method for determining bismuth (Ⅲ)was established. A solution of 0.1 mol/L HNO3 was selected as the supporting electrolyte. Factors affecting the Bi(Ⅲ) UPD and stripping steps were investigated and an opthmized analytical procedure was developed. The calibration plots for Bi(Ⅲ) concentration in the range 1.25 × 10-8-1.0 × 10-7 mol/L were obtained. The detection limit, calculated as three times the standard deviation of the analytical signal of 8.3×10-8 mol/L for a 90 s electrodeposition at 0.00 V (while the solution magnetically stirred at a speed of 300 rpm), was 7.5× 10-9 mol/ L. For8 successive determinations of 1.25 × 10-7 mol/L Bi(Ⅲ), the obtained RSD (relative standard deviation) was 0.4%. The developed method was applied to bismuth determining in medicine and urine samples. The analytical results were compared with that of atomic emission spectrometry (AES) method.

  10. Glass composite waste forms for iodine confined in bismuth-embedded SBA-15

    Science.gov (United States)

    Yang, Jae Hwan; Park, Hwan Seo; Ahn, Do-Hee; Yim, Man-Sung

    2016-11-01

    The aim of this study was to stabilize bismuth-embedded SBA-15 that captured iodine gas by fabrication of monolithic waste forms. The iodine containing waste was mixed with Bi2O3 (a stabilizing additive) and low-temperature sintering glass followed by pelletizing and the sintering process to produce glass composite materials. Iodine volatility during the sintering process was significantly affected by the ratio of Bi2O3 and the glass composition. It was confirmed that BiI3, the main iodine phase within bismuth-embedded SBA-15, was effectively transformed to the mixed phases of Bi5O7I and BiOI. The initial leaching rates of iodine from the glass composite waste forms ranged 10-3-10-2 g/m2 day, showing the stability of the iodine phases encapsulated by the glassy networks. It was also observed that common groundwater anions (e.g., chloride, carbonate, sulfite, and fluoride) elevated the iodine leaching rate by anion exchange reactions. The present results suggest that the glass composite waste form of bismuth-embedded SBA-15 could be a candidate material for stable storage of 129I.

  11. Effect of bismuth ion substitution on structural properties of zinc ferrite nanoparticles

    Directory of Open Access Journals (Sweden)

    Naraavula Suresh Kumar

    2016-06-01

    Full Text Available Bismuth doped nano zinc ferrite particles having the general formula ZnFe2-xBixO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25 were synthesized by sol-gel combustion method. The effect of bismuth doping on structural properties were investigated. The X-ray diffraction (XRD spectra confirm the single phase cubic spinel structure. The average crystallite sizes of all the samples were determined by Debye-Scherrer equation and are in the range 16–20 nm. The lattice parameter increases with the increase of bismuth ion concentration. This is due to the larger ionic radius of Bi3+ ions substituting smaller Fe3+ ions at octahedral sites (B-sites. The surface morphology of all compounds was studied by scanning electron microscope (SEM. The microstructure analysis and the particle size were examined by transmission electron microscope (TEM. The compositional stoichiometry of these samples was verified by energy dispersive spectroscopy (EDS analysis.

  12. Dirac fermions at high-index surfaces of bismuth chalcogenide topological insulator nanostructures

    Science.gov (United States)

    Virk, Naunidh; Yazyev, Oleg V.

    2016-02-01

    Binary bismuth chalcogenides Bi2Se3, Bi2Te3, and related materials are currently being extensively investigated as the reference topological insulators (TIs) due to their simple surface-state band dispersion (single Dirac cone) and relatively large bulk band gaps. Nanostructures of TIs are of particular interest as an increased surface-to-volume ratio enhances the contribution of surfaces states, meaning they are promising candidates for potential device applications. So far, the vast majority of research efforts have focused on the low-energy (0001) surfaces, which correspond to natural cleavage planes in these layered materials. However, the surfaces of low-dimensional nanostructures (nanoplatelets, nanowires, nanoribbons) inevitably involve higher-index facets. We perform a systematic ab initio investigation of the surfaces of bismuth chalcogenide TI nanostructures characterized by different crystallographic orientations, atomic structures and stoichiometric compositions. We find several stable terminations of high-index surfaces, which can be realized at different values of the chemical potential of one of the constituent elements. For the uniquely defined stoichiometric termination, the topological Dirac fermion states are shown to be strongly anisotropic with a clear dependence of Fermi velocities and spin polarization on the surface orientation. Self-doping effects and the presence of topologically trivial mid-gap states are found to characterize the non-stoichiometric surfaces. The results of our study pave the way towards experimental control of topologically protected surface states in bismuth chalcogenide nanostructures.

  13. Thermochemically evolved nanoplatelets of bismuth selenide with enhanced thermoelectric figure of merit

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Zulfiqar; Cao, Chuanbao, E-mail: cbcao@bit.edu.cn; Butt, Faheem K.; Tahir, Muhammad; Tanveer, M.; Aslam, Imran; Rizwan, Muhammad; Idrees, Faryal; Khalid, Syed [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Butt, Sajid [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-11-15

    We firstly present a simple thermochemical method to fabricate high-quality Bi{sub 2}Se{sub 3} nanoplatelets with enhanced figure of merit using elemental bismuth and selenium powders as precursors. The crystal structure of as synthesized products is characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) measurements. Morphological and chemical synthetic parameters are investigated through a series of experiments; thickness and composition of the platelets are well controlled in large scale production. Subsequently spark plasma sintering (SPS) is performed to fabricate n-type nanostructured bulk thermoelectric materials. Raman Spectroscopy of the two selected samples with approximately of 50 and 100 nm thicknesses shows three vibrational modes. The lower thickness sample exhibits the maximum red shift of about 2.17 cm{sup -1} and maximum broadening of about 10 cm{sup -1} by in-plane vibrational mode E{sup 2}{sub g}. The enhanced value of figure of merit ∼0.41 is obtained for pure phase bismuth selenide to the best of our knowledge. We observe metallic conduction behavior while semiconducting behavior for nanostructured bismuth selenide is reported elsewhere which could be due to different synthetic techniques adopted. These results clearly suggest that our adopted synthetic technique has profound effect on the electronic and thermoelectric transport properties of this material.

  14. Opto-electronic properties of bismuth oxide films presenting different crystallographic phases

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Celia L. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Depablos-Rivera, Osmary, E-mail: osmarydep@yahoo.com [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Silva-Bermudez, Phaedra [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Instituto Nacional de Rehabilitación, Calz. México Xochimilco No. 289 Col. Arenal de Guadalupe, C.P.14389, Ciudad de México, D.F. (Mexico); Muhl, Stephen [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Zeinert, Andreas; Lejeune, Michael; Charvet, Stephane; Barroy, Pierre [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex 1 (France); Camps, Enrique [Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, kilómetro 36.5. La Marquesa, Municipio de Ocoyoacac, CP 52750, Estado de México (Mexico); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico)

    2015-03-02

    The optical, electrical and structural properties of bismuth oxide thin films deposited by radio frequency reactive magnetron sputtering were studied. The Bi{sub 2}O{sub 3} thin films were grown on Si and glass substrates under different power and substrate temperatures in an oxygen-enriched plasma leading to films with different crystalline phase as evidenced by X-ray diffraction and Raman spectroscopy. The optical properties of the films were measured using ellipsometric spectroscopy and optical transmission spectra. In order to parameterize the optical dispersion functions (n, k) of the films, the Tauc–Lorentz dispersion model was used. The optical bandgap was then assessed by different methods and the results are compared to the thermal variations of the electrical resistivity of the films. It was found that the refractive index, extinction coefficient and optical gap strongly depend on the deposition conditions and the crystalline phase; the fluorite defect cubic δ-Bi{sub 2}O{sub 3} phase showed the lowest optical gap and lower resistivity. - Highlights: • Different bismuth oxide phases were obtained by sputtering. • The power and substrate temperature were the two key parameters. • Room temperature delta-Bi{sub 2}O{sub 3} thin films were obtained. • The optical bandgap was around 1.5 and 2.2 eV, depending on the phase. • The bismuth oxide films presented activation energies around 1 eV.

  15. Landau spectrum and twin boundaries of bismuth in the extreme quantum limit.

    Science.gov (United States)

    Zhu, Zengwei; Fauqué, Benoît; Malone, Liam; Antunes, Arlei Borba; Fuseya, Yuki; Behnia, Kamran

    2012-09-11

    The Landau spectrum of bismuth is complex and includes many angle-dependent lines in the extreme quantum limit. The adequacy of single-particle theory to describe this spectrum in detail has been an open issue. Here, we present a study of angle-resolved Nernst effect in bismuth, which maps the angle-resolved Landau spectrum for the entire solid angle up to 28 T. The experimental map is in good agreement with the results of a theoretical model with parabolic dispersion for holes and an extended Dirac Hamiltonian for electrons. The angular dependence of additional lines in the Landau spectrum allows us to uncover the mystery of their origin. They correspond to the lines expected for the hole Landau levels in a secondary crystal tilted by 108°, the angle between twinned crystals in bismuth. According to our results, the electron reservoirs of the two identical tilted crystals have different chemical potentials, and carriers across the twin boundary have different concentrations. An exceptional feature of this junction is that it separates two electron-hole compensated reservoirs. The link between this edge singularity and the states wrapping a three-dimensional electron gas in the quantum limit emerges as an outstanding open question.

  16. LiBi3S5-A lithium bismuth sulfide with strong cation disorder

    Science.gov (United States)

    Nakhal, Suliman; Wiedemann, Dennis; Stanje, Bernhard; Dolotko, Oleksandr; Wilkening, Martin; Lerch, Martin

    2016-06-01

    Among chalcogenide semiconductors for thermoelectric applications, alkali-metal bismuth compounds occur in many complex compositions favorable for high performance. Although LiBi3S5 had been announced in 1977, the potential 1D lithium-ion conductor has hitherto eluded selective synthesis and structure determination. In this study, we present a solid-state route to phase-pure LiBi3S5 powder starting from LiBiS2 and Bi2S3. Neutron diffractograms and lithium NMR spectra reveal its crystal structure to be a cation-disordered variety of the AgBi3S5 type (synthetic pavonite; monoclinic, C2/m). Topological analyses and lithium NMR relaxometry suggest that correlated lithium-ion diffusion with activation energies up to 0.66(2) eV occurs along the channels in b direction including tetrahedral voids. Because of cation disorder, immobile bismuth(III) ions clog these pathways, making LiBi3S5 a moderate to poor ionic conductor. The synthesis route reported is nonetheless promising for new lithium bismuth sulfides with, possibly ordered, structure types of the pavonite homologous series.

  17. Dirac fermions at high-index surfaces of bismuth chalcogenide topological insulator nanostructures

    Science.gov (United States)

    Virk, Naunidh; Yazyev, Oleg V.

    2016-01-01

    Binary bismuth chalcogenides Bi2Se3, Bi2Te3, and related materials are currently being extensively investigated as the reference topological insulators (TIs) due to their simple surface-state band dispersion (single Dirac cone) and relatively large bulk band gaps. Nanostructures of TIs are of particular interest as an increased surface-to-volume ratio enhances the contribution of surfaces states, meaning they are promising candidates for potential device applications. So far, the vast majority of research efforts have focused on the low-energy (0001) surfaces, which correspond to natural cleavage planes in these layered materials. However, the surfaces of low-dimensional nanostructures (nanoplatelets, nanowires, nanoribbons) inevitably involve higher-index facets. We perform a systematic ab initio investigation of the surfaces of bismuth chalcogenide TI nanostructures characterized by different crystallographic orientations, atomic structures and stoichiometric compositions. We find several stable terminations of high-index surfaces, which can be realized at different values of the chemical potential of one of the constituent elements. For the uniquely defined stoichiometric termination, the topological Dirac fermion states are shown to be strongly anisotropic with a clear dependence of Fermi velocities and spin polarization on the surface orientation. Self-doping effects and the presence of topologically trivial mid-gap states are found to characterize the non-stoichiometric surfaces. The results of our study pave the way towards experimental control of topologically protected surface states in bismuth chalcogenide nanostructures. PMID:26847409

  18. The fabrication and thermal properties of bismuth-aluminum oxide nanothermometers

    Science.gov (United States)

    Wang, Chiu-Yen; Chen, Shih-Hsun; Tsai, Ping-Hsin; Chiou, Chung-Han; Hsieh, Sheng-Jen

    2017-01-01

    Bismuth (Bi) nanowires, well controlled in length and diameter, were prepared by using an anodic aluminum oxide (AAO) template-assisted molding injection process with a high cooling rate. A high performance atomic layer deposition (ALD)-capped bismuth-aluminum oxide (Bi-Al2O3) nanothermometer is demonstrated that was fabricated via a facile, low-cost and low-temperature method, including AAO templated-assisted molding injection and low-temperature ALD-capped processes. The thermal behaviors of Bi nanowires and Bi-Al2O3 nanocables were studied by in situ heating transmission electron microscopy. Linear thermal expansion of liquid Bi within native bismuth oxide nanotubes and ALD-capped Bi-Al2O3 nanocables were evaluated from 275 °C to 700 °C and 300 °C to 1000 °C, respectively. The results showed that the ALD-capped Bi-Al2O3 nanocable possesses the highest working temperature, 1000 °C, and the broadest operation window, 300 °C-1000 °C, of a thermal-expanding type nanothermometer. Our innovative approach provides another way of fabricating core-shell nanocables and to further achieve sensing local temperature under an extreme high vacuum environment.

  19. 铋含量对铅铋合金表面张力的影响分析%Influence of Bismuth Content on Surface Tension of Lead-bismuth Alloy

    Institute of Scientific and Technical Information of China (English)

    王龙; 徐敬尧; 徐刚; 刘少军; 黄群英

    2013-01-01

    Liquid lead-bismuth alloy has been considered as the potential candidates for the liquid spallation targets and the coolant of accelerator driven sub-critical system (ADS ) . Surface tension is one of the important thermal and physical properties parameters of lead-bismuth alloy , and temperature and chemical composition are important influence factors of surface tension . In this paper , the surface tension of liquid lead-bismuth alloy was measured by sessile drop (SD ) method . The results indicate that the surface tension of lead-bismuth alloy firstly increases and then decreases with the increase of the test temperature ,and the surface tension for low test temperature is significantly small .At the same temperature ,the surface tension of lead-bismuth alloy decreases with the increase of bismuth content , and segregation of bismuth onto the surface of molten lead-bismuth alloy is a key factor leading to the smaller surface tension .T he results of this study provide basic reference for composition optimization of lead-bismuth alloy ,w hich is of great significance for the development of spallation targets and the coolant materials of accelerated driven sub-critical system .%液态铅铋合金是加速器驱动的次临界系统(ADS )中散裂靶兼冷却剂的主要候选材料。表面张力是液态铅铋合金的重要热物性参数之一,而温度和化学组成是影响表面张力的关键因素。本文采用静滴法测量了5种不同成分铅铋合金的表面张力。实验结果显示:在测试温度范围内,铅铋合金的表面张力均随温度的升高先增大后减小,且在低温区表面张力非常小;相同温度下,铅铋合金的表面张力随Bi含量的增大逐渐降低,其中Bi的表面偏聚是导致其变小的重要因素之一。本研究结果为铅铋合金的成分优化提供了基本参考,对发展ADS散裂靶和冷却剂材料具有重要意义。

  20. Controlled cadmium telluride thin films for solar-cell applications. Final technical report, June 1, 1980-May 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Das, M.B.; Krishnaswamy, S.V.

    1981-06-01

    The objectives of this contract were to carry out a systematic study on the preparation and characterization of rf-sputtered CdTe thin films in order to establish reproducibility of the films with good electrical characteristics and to demonstrate the feasibility of fabricating various types of junctions and ohmic contacts with reproducible characteristics and finally to optimize the most promising solar cell structure in order to achieve an efficiency of 6% or higher. Efforts have been directed to the control of various sputtering parameters in order to obtain good quality films. The structure, crystallographic, compositional and electrical properties of cadmium telluride films sputtered over a wide range of conditions have been evaluated. A series of doping experiments have been carried out using primarily Cd, Te, In, as the n-type dopants and Cu as the p-type dopant. Of these dopants, indium doping provided films with which S.B. junctions can be obtained for further electrical characterization. Use of cadmium overpressure during CdTe:In sputtering has improved the film characteristics. Ion Beam Sputtering was attempted as an alternative technique for film preparation. For lack of time and due to a number of mechanical failures, no significant results could be obtained.

  1. Derived reference doses for three compounds used in the photovoltaics industry: Copper indium diselenide, copper gallium diselenide, and cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Bernholc, N.; DePhillips, M.P.; Viren, J.

    1995-07-06

    Polycrystalline thin-film photovoltaic modules made from copper indium diselenide (CIS), copper gallium diselenide (CGS), and cadmium telluride (CdTe) arc nearing commercial development. A wide range of issues are being examined as these materials move from the laboratory to large-scale production facilities to ensure their commercial success. Issues of traditional interest include module efficiency, stability and cost. More recently, there is increased focus given to environmental, health and safety issues surrounding the commercialization of these same devices. An examination of the toxicological properties of these materials, and their chemical parents is fundamental to this discussion. Chemicals that can present large hazards to human health or the environment are regulated often more strictly than those that are less hazardous. Stricter control over how these materials are handled and disposed can increase the costs associated with the production and use of these modules dramatically. Similarly, public perception can be strongly influenced by the inherent biological hazard that these materials possess. Thus, this report: presents a brief background tutorial on how toxicological data are developed and used; overviews the toxicological data available for CIS, CGS and CdTe; develops ``reference doses`` for each of these compounds; compares the reference doses for these compounds with those of their parents; discusses the implications of these findings to photovoltaics industry.

  2. Physical properties of Ag-doped cadmium telluride thin films fabricated by closed-space sublimation technique

    Science.gov (United States)

    Abbas Shah, N.; Ali, A.; Aqili, A. K. S.; Maqsood, A.

    2006-05-01

    Cadmium telluride (CdTe) thin films were prepared by the closed-space sublimation (CSS) technique, using CdTe powder as evaporant onto substrates of water-white glass. In the next step, the annealed films at 450 °C for 30 min were dipped in AgNO 3-H 2O solution at room temperature. These films were again annealed at 450 °C for 1 h to obtain silver-doped samples. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrically i.e. DC electrical resistivity as well as photo resistivity by van der Pauw method at room temperature, dark conductivity, activation energy analysis as a function of temperature by two-probe method under vacuum, and spectrophotometry. The electron microprobe analyzer (EMPA) results showed an increase of Ag content composition in the samples by increasing the immersion time of films in solution. The Hall measurements indicated the increase in mobility and carrier concentrations of CdTe films by doping of Ag. A significant change in the shape and size of the CdTe grains were observed.

  3. Improved Sensitization of Zinc Oxide Nanorods by Cadmium Telluride Quantum Dots through Charge Induced Hydrophilic Surface Generation

    Directory of Open Access Journals (Sweden)

    Karthik Laxman

    2014-01-01

    Full Text Available This paper reports on UV-mediated enhancement in the sensitization of semiconductor quantum dots (QDs on zinc oxide (ZnO nanorods, improving the charge transfer efficiency across the QD-ZnO interface. The improvement was primarily due to the reduction in the interfacial resistance achieved via the incorporation of UV light induced surface defects on zinc oxide nanorods. The photoinduced defects were characterized by XPS, FTIR, and water contact angle measurements, which demonstrated an increase in the surface defects (oxygen vacancies in the ZnO crystal, leading to an increase in the active sites available for the QD attachment. As a proof of concept, a model cadmium telluride (CdTe QD solar cell was fabricated using the defect engineered ZnO photoelectrodes, which showed ∼10% increase in photovoltage and ∼66% improvement in the photocurrent compared to the defect-free photoelectrodes. The improvement in the photocurrent was mainly attributed to the enhancement in the charge transfer efficiency across the defect rich QD-ZnO interface, which was indicated by the higher quenching of the CdTe QD photoluminescence upon sensitization.

  4. Crystal structures of a pentavalent bismuthate, SrBi2O6 and a lead bismuth oxide (Pb1/3Bi2/3O1.4

    Directory of Open Access Journals (Sweden)

    Nobuhiro Kumada

    2014-06-01

    Full Text Available The crystal structures of a pentavalent bismuthate, SrBi2O6 with the PbSb2O6-type structure and a lead bismuth oxide, (Pb1/3Bi2/3O1.4 with the fluorite-type structure were refined by using neutron diffraction data. The final R-factors were Rwp = 4.49, Rp = 3.46, RI = 4.50 and RF = 1.70% for SrBi2O6 and Rwp = 5.04, Rp = 3.93, RI = 5.47 and RF = 4.26% for (Pb1/3Bi2/3O1.4. SrBi2O6 prepared from NaBiO3·1.4H2O is the first example of the bismuthate with the PbSb2O6-type structure. The fluorite-type lead bismuth oxide, (Pb1/3Bi2/3O1.4 was obtained by heating the PbSb2O6-type lead bismuthate, PbBi2O5.9·H2O which was prepared also from NaBiO3·1.4H2O.

  5. Li3PO4 Matrix Enables a Long Cycle Life and High Energy Efficiency Bismuth-Based Battery.

    Science.gov (United States)

    Sun, Chuan-Fu; Hu, Junkai; Wang, Peng; Cheng, Xi-Yuan; Lee, Sang Bok; Wang, YuHuang

    2016-09-14

    Bismuth is a lithium-ion battery anode material that can operate at an equilibrium potential higher than graphite and provide a capacity twice as high as that of Li4Ti5O12, making it intrinsically free from lithium plating that may cause catastrophic battery failure. However, the potential of bismuth is hampered by its inferior cyclability (limited to tens of cycles). Here, we propose an "ion conductive solid-state matrix" approach to address this issue. By homogeneously confining bismuth nanoparticles in a solid-state γ-Li3PO4 matrix that is electrochemically formed in situ, the resulting composite anode exhibits a reversible capacity of 280 mA hours per gram (mA h/g) at a rate of 100 mA/g and a record cyclability among bismuth-based anodes up to 500 cycles with a capacity decay rate of merely 0.071% per cycle. We further show that full-cell batteries fabricated from this composite anode and commercial LiFePO4 cathode deliver a stable cell voltage of ∼2.5 V and remarkable energy efficiency up to 86.3%, on par with practical batteries (80-90%). This work paves a way for harnessing bismuth-based battery chemistry for the design of high capacity, safer lithium-ion batteries to meet demanding applications such as electric vehicles.

  6. The cytotoxicity of organobismuth compounds with certain molecular structures can be diminished by replacing the bismuth atom with an antimony atom in the molecules.

    Science.gov (United States)

    Kohri, Kumiko; Yoshida, Eiko; Yasuike, Shuji; Fujie, Tomoya; Yamamoto, Chika; Kaji, Toshiyuki

    2015-06-01

    Organic-inorganic hybrid molecules, which are composed of an organic structure and metal(s), are indispensable for synthetic chemical reactions; however, their toxicity has been incompletely understood. In the present study, we discovered two cytotoxic organobismuth compounds whose cytotoxicity diminished upon replacement of the intramolecular bismuth atom with an antimony atom. The intracellular accumulation of the organobismuth compounds was much higher than that of the organoantimony compounds with the corresponding organic structures. We also showed that both the organic structure and bismuth atom are required for certain organobismuth compounds to exert their cytotoxic effect, suggesting that the cytotoxicity of such a compound is a result of an interaction between the organic structure and the bismuth atom. The present data suggest that organobismuth compounds with certain molecular structures exhibit cytotoxicity via an interaction between the molecular structure and the bismuth atom, and this cytotoxicity can be diminished by replacing the bismuth atom with an antimony atom, resulting in lower intracellular accumulation.

  7. Dual-modality, fluorescent, PLGA encapsulated bismuth nanoparticles for molecular and cellular fluorescence imaging and computed tomography

    Science.gov (United States)

    Swy, Eric R.; Schwartz-Duval, Aaron S.; Shuboni, Dorela D.; Latourette, Matthew T.; Mallet, Christiane L.; Parys, Maciej; Cormode, David P.; Shapiro, Erik M.

    2014-10-01

    Reports of molecular and cellular imaging using computed tomography (CT) are rapidly increasing. Many of these reports use gold nanoparticles. Bismuth has similar CT contrast properties to gold while being approximately 1000-fold less expensive. Herein we report the design, fabrication, characterization, and CT and fluorescence imaging properties of a novel, dual modality, fluorescent, polymer encapsulated bismuth nanoparticle construct for computed tomography and fluorescence imaging. We also report on cellular internalization and preliminary in vitro and in vivo toxicity effects of these constructs. 40 nm bismuth(0) nanocrystals were synthesized and encapsulated within 120 nm Poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles by oil-in-water emulsion methodologies. Coumarin-6 was co-encapsulated to impart fluorescence. High encapsulation efficiency was achieved ~70% bismuth w/w. Particles were shown to internalize within cells following incubation in culture. Bismuth nanocrystals and PLGA encapsulated bismuth nanoparticles exhibited >90% and >70% degradation, respectively, within 24 hours in acidic, lysosomal environment mimicking media and both remained nearly 100% stable in cytosolic/extracellular fluid mimicking media. μCT and clinical CT imaging was performed at multiple X-ray tube voltages to measure concentration dependent attenuation rates as well as to establish the ability to detect the nanoparticles in an ex vivo biological sample. Dual fluorescence and CT imaging is demonstrated as well. In vivo toxicity studies in rats revealed neither clinically apparent side effects nor major alterations in serum chemistry and hematology parameters. Calculations on minimal detection requirements for in vivo targeted imaging using these nanoparticles are presented. Indeed, our results indicate that these nanoparticles may serve as a platform for sensitive and specific targeted molecular CT and fluorescence imaging.Reports of molecular and cellular imaging using

  8. Comparison of catalytic activity of bismuth substituted cobalt ferrite nanoparticles synthesized by combustion and co-precipitation method

    Science.gov (United States)

    Kiran, Venkat Savunthari; Sumathi, Shanmugam

    2017-01-01

    In this study, cobalt ferrite and bismuth substituted cobalt ferrite (CoFe2-xBixO4x=0, 0.1) nanoparticles were synthesized by two different methods viz combustion and co-precipitation. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy-energy dispersive X-ray analyzer (SEM-EDX) and vibrating sample magnetometer (VSM). The results of powder XRD pattern showed an increase in lattice parameter and decrease in particle size of cobalt ferrite by the substitution of bismuth. Catalytic activity of cobalt ferrite and bismuth substituted cobalt ferrite nanoparticles synthesized by two different methods were compared for the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a reducing agent.

  9. Hydrothermal synthesis and crystal structure of a new lithium copper bismuth oxide, LiCuBiO4

    Science.gov (United States)

    Kumada, Nobuhiro; Nakamura, Ayumi; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Yamamoto, Hajime; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2017-01-01

    A new lithium copper bismuth oxide, LiCuBiO4 was prepared by hydrothermal reaction using NaBiO30.1*4H2O. The crystal structural model of this compound was refined by using synchrotron X-ray powder diffraction data. This bismuthate has the LiCuSbO4 related structure with the orthorhombic cell (Space group: Pnma) of a=10.9096(9), b=5.8113(5) and c=5.0073(4) Å, and the final R-factors were Rwp=4.84 and Rp=3.58%. This compound is the first example of a lithium copper bismuthate containing Bi5+. An antiferromagnetic ordering of Cu2+ moment was observed at 6 K.

  10. The 3-5 semiconductor solid solution single crystal growth. [low gravity float zone growth experiments using gallium indium antimonides and cadmium tellurides

    Science.gov (United States)

    Gertner, E. R.

    1980-01-01

    Techniques used for liquid and vapor phase epitaxy of gallium indium arsenide are described and the difficulties encountered are examined. Results show that the growth of bulk III-V solid solution single crystals in a low gravity environment will not have a major technological impact. The float zone technique in a low gravity environment is demonstrated using cadmium telluride. It is shown that this approach can result in the synthesis of a class of semiconductors that can not be grown in normal gravity because of growth problems rooted in the nature of their phase diagrams.

  11. NIR photoluminescence of bismuth-doped CsCdBr{sub 3} – The first ternary bromide phase with a univalent bismuth impurity center

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, Alexey N., E-mail: alexey.romanov@list.ru [N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4 Kosygina Street, 119991 (Russian Federation); Veber, Alexander A. [Universität Erlangen-Nürnberg, Lehrstuhl für Glas und Keramik, Martensstraße 5, 91058 Erlangen (Germany); Vtyurina, Daria N. [N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4 Kosygina Street, 119991 (Russian Federation); Kouznetsov, Mikhail S.; Zaramenskikh, Ksenia S.; Lisitsky, Igor S. [State Scientific-Research and Design Institute of Rare-Metal Industry “Giredmet” JSC, 5-1 B.Tolmachevsky Lane, 119017 Moscow (Russian Federation); Fattakhova, Zukhra T.; Haula, Elena V. [N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4 Kosygina Street, 119991 (Russian Federation); Loiko, Pavel A.; Yumashev, Konstantin V. [Center for Optical Materials and Technologies, Belarusian National Technical University, 65/17 Nezavisimosti Avenue, 220013 Minsk (Belarus); Korchak, Vladimir N. [N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4 Kosygina Street, 119991 (Russian Federation)

    2015-11-15

    Single crystals of ternary bromide phase CsCdBr{sub 3} doped with univalent bismuth cations are prepared for the first time by the Bridgman method. Bi{sup +} impurity center emits a broadband long-lived near-infrared photoluminescence with a maximum at ~1053 nm. The characteristics of this photoluminescence and its relations with the energy spectrum of Bi{sup +} impurity center are discussed. A comparison of Bi{sup +} photoluminescence in CsCdBr{sub 3} and ternary chlorides (studied previously) is performed. - Highlights: • Single crystals of Bi{sup +}-doped ternary bromide CsCdBr{sub 3} were prepared. • Broadband NIR photoluminescence was observed from Bi{sup +}-doped CsCdBr{sub 3}. • Single optical center is responsible for NIR emission in Bi{sup +}-doped CsCdBr{sub 3}.

  12. Myocardial perfusion imaging with a cadmium zinc telluride-based gamma camera versus invasive fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Mouden, Mohamed [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Ottervanger, Jan Paul; Timmer, Jorik R. [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Knollema, Siert; Reiffers, Stoffer; Oostdijk, Ad H.J.; Jager, Pieter L. [Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Boer, Menko-Jan de [University Medical Centre Nijmegen, Department of Cardiology, Nijmegen (Netherlands)

    2014-05-15

    Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization. (orig.)

  13. Downstream resource utilization following hybrid cardiac imaging with an integrated cadmium-zinc-telluride/64-slice CT device

    Energy Technology Data Exchange (ETDEWEB)

    Fiechter, Michael; Kaufmann, Philipp A. [University Hospital Zurich, Department of Radiology, Cardiac Imaging, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology (ZIHP), Zurich (Switzerland); Ghadri, Jelena R.; Wolfrum, Mathias; Kuest, Silke M.; Pazhenkottil, Aju P.; Nkoulou, Rene N.; Herzog, Bernhard A.; Gebhard, Catherine; Fuchs, Tobias A.; Gaemperli, Oliver [University Hospital Zurich, Department of Radiology, Cardiac Imaging, Zurich (Switzerland)

    2012-03-15

    Low yield of invasive coronary angiography and unnecessary coronary interventions have been identified as key cost drivers in cardiology for evaluation of coronary artery disease (CAD). This has fuelled the search for noninvasive techniques providing comprehensive functional and anatomical information on coronary lesions. We have evaluated the impact of implementation of a novel hybrid cadmium-zinc-telluride (CZT)/64-slice CT camera into the daily clinical routine on downstream resource utilization. Sixty-two patients with known or suspected CAD were referred for same-day single-session hybrid evaluation with CZT myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA). Hybrid MPI/CCTA images from the integrated CZT/CT camera served for decision-making towards conservative versus invasive management. Based on the hybrid images patients were classified into those with and those without matched findings. Matched findings were defined as the combination of MPI defect with a stenosis by CCTA in the coronary artery subtending the respective territory. All patients with normal MPI and CCTA as well as those with isolated MPI or CCTA finding or combined but unmatched findings were categorized as ''no match''. All 23 patients with a matched finding underwent invasive coronary angiography and 21 (91%) were revascularized. Of the 39 patients with no match, 5 (13%, p < 0.001 vs matched) underwent catheterization and 3 (8%, p < 0.001 vs matched) were revascularized. Cardiac hybrid imaging in CAD evaluation has a profound impact on patient management and may contribute to optimal downstream resource utilization. (orig.)

  14. Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

    Energy Technology Data Exchange (ETDEWEB)

    Verger, Antoine; Karcher, Gilles [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Djaballah, Wassila [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Fourquet, Nicolas [Clinique Pasteur, Toulouse (France); Rouzet, Francois; Le Guludec, Dominique [AP-HP, Hopital Bichat, Department of Nuclear Medicine, Paris (France); INSERM U 773 Inserm and Denis Diderot University, Paris (France); Koehl, Gregoire; Roch, Veronique [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Imbert, Laetitia [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Centre Alexis Vautrin, Department of Radiotherapy, Vandoeuvre (France); Poussier, Sylvain [INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Fay, Renaud [INSERM, Centre d' Investigation Clinique CIC-P 9501, Nancy (France); Marie, Pierre-Yves [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); INSERM U961, Nancy (France); Hopital de Brabois, CHU-Nancy, Medecine Nucleaire, Vandoeuvre-les-Nancy (France)

    2013-03-15

    The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving {sup 201}Tl (n = 120) or {sup 99m}Tc-sestamibi injected at low dose at stress ({sup 99m}Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ({sup 99m}Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, {sup 201}Tl 92 %, {sup 99m}Tc-Low 86 %, {sup 99m}Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the {sup 201}Tl or {sup 99m}Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 {+-} 101 kcounts) and dramatically enhanced with CZT SPECT (+279 {+-} 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

  15. The energetic impact of small Cd{sub x}Te{sub y} clusters on Cadmium Telluride

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Miao, E-mail: M.Yu2@lboro.ac.uk; Kenny, Steven D., E-mail: S.D.Kenny@lboro.ac.uk

    2015-06-01

    Cadmium Telluride (CdTe) is an excellent material for low-cost, high efficiency thin film solar cells. It is important to do research on how these defects are formed during the growth process, since defects lower the efficiency of solar cells. In this work we use computer simulation to predict the growth of a sputter deposited CdTe thin film. Single deposition tests have been performed, to study the behaviour of deposited clusters under different conditions. We deposit a Cd{sub x}Te{sub y} (x,y = 0,1) cluster onto the (100) and (111) Cd and Te terminated surfaces with energies ranging from 1 to 40 eV. More than 1000 simulations have been performed for each of these cases so as to sample the possible deposition positions and to collect sufficient statistics. The results show that Cd atoms are more readily sputtered from the surface than Te atoms and the sticking probability is higher on Te terminated surfaces than Cd terminated surfaces. They also show that increasing the deposition energy typically leads to an increase in the number of atoms sputtered from the system and tends to decrease the number of atoms that sit on or in the surface layer, whilst increasing the number of interstitials observed. - Highlights: • Deposition of Cd, Te and CdTe particles on (100) and (111) Cd and Te surfaces • Cd atoms are more readily sputtered from the surface than Te atoms. • The Te terminated surfaces have a higher sticking probability than the Cd ones. • Higher impact energies imply more sputtered atoms from the surface.

  16. Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Arkundato, Artoto [Physics Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Su' ud, Zaki [Physics Department, Faculty of Mathematical and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung (Indonesia); Sudarko [Chemistry Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Shafii, Mohammad Ali [Physics Department, Faculty of Mathematical and Natural Sciences, Andalas University, Padang (Indonesia); Celino, Massimo [ENEA, CR Casaccia, Via Anguillarese 301, Rome (Italy)

    2014-09-30

    Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

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

    Science.gov (United States)

    Nair, M. T. S.; Nair, Padmanabhan K.; Garcia, Victor 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.

  18. Investigation of concentration quenching and 1.3 microm emission in Nd(3+)-doped bismuth glasses.

    Science.gov (United States)

    Nie, Qiuhua; Li, Xujie; Dai, Shixun; Xu, Tiefeng; Jin, Zhenjuan; Zhang, Xianghua

    2008-08-01

    Nd(2)O(3)-doped 70Bi(2)O(3)-20B(2)O(3)-10SiO(2)-xNd(2)O(3) (x=0.1, 0.3, 0.5, 0.7, 1.0, 1.5 mol%) bismuth glasses were prepared by the conventional melt-quenching method, and the Nd(3+):(4)F(3/2)-->(4)I(13/2) fluorescence properties had been studied for different Nd(3+) concentrations. The Judd-Ofelt analysis for Nd(3+) ions in bismuth boron silicate glasses was also performed on the base of absorption spectrum. The transition probabilities, excited state lifetimes, the fluorescence branching ratios, quantum efficiency and the stimulated emission cross-sections of (4)F(3/2)-->(4)I(13/2) transition were calculated and discussed. Based on the electric dipole-dipole interaction theory, the interaction parameters: C(DD), for the energy migration rate (4)F(3/2), (4)I(9/2)-->(4)F(3/2), (4)I(9/2) and C(DA), for cross-relaxation rate (4)F(3/2), (4)I(9/2)-->(4)I(15/2), (4)I(15/2), and/or (4)F(3/2), (4)I(9/2)-->(4)I(13/2), (4)I(15/2) in bismuth boron silicate glasses were about 18.4 x 10(-40)cm(6)/s and 3.4 x 10(-40)cm(6)/s, respectively.

  19. Origin of broad NIR photoluminescence in bismuthate glass and Bi-doped glasses at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Mingying; Zollfrank, Cordt; Wondraczek, Lothar [Lehrstuhl fuer Glas und Keramik, WW3, Friedrich Alexander Universitaet Erlangen-Nuernberg, Martensstrasse 5, D-91058 Erlangen (Germany)], E-mail: mingying.peng@ww.uni-erlangen.de, E-mail: lothar.wondraczek@ww.uni-erlangen.de

    2009-07-15

    Bi-doped glasses with broadband photoluminescence in the near-infrared (NIR) spectral range are presently receiving significant consideration for potential applications in telecommunications, widely tunable fiber lasers and spectral converters. However, the origin of NIR emission remains disputed. Here, we report on NIR absorption and emission properties of bismuthate glass and their dependence on the melting temperature. Results clarify that NIR emission occurs from the same centers as it does in Bi-doped glasses. The dependence of absorption and NIR emission of bismuthate glasses on the melting temperature is interpreted as thermal dissociation of Bi{sub 2}O{sub 3} into elementary Bi. Darkening of bismuthate glass melted at 1300 deg. C is due to the agglomeration of Bi atoms. The presence of Bi nanoparticles is confirmed by transmission electron microscopy, high-resolution energy dispersive x-ray spectroscopy and element distribution mapping. By adding antimony oxide as an oxidation agent to the glass, NIR emission centers can be eliminated and Bi{sup 3+} is formed. By comparing with atomic spectral data, absorption bands at {approx}320 , {approx}500 , 700 , 800 and 1000 nm observed in Bi-doped glasses are assigned to Bi{sup 0} transitions {sup 4}S{sub 3/2}{yields}{sup 2}P{sub 3/2}, {sup 4}S{sub 3/2}{yields}{sup 2}P{sub 1/2}, {sup 4}S{sub 3/2}{yields}{sup 2}D{sub 5/2}, {sup 4}S{sub 3/2}{yields}{sup 2}D{sub 3/2}(2) and {sup 4}S{sub 3/2}{yields}{sup 2}D{sub 3/2}(1), respectively, and broadband NIR emission is assigned to the transition {sup 2}D{sub 3/2}(1){yields}{sup 4}S{sub 3/2}.

  20. Origin of broad NIR photoluminescence in bismuthate glass and Bi-doped glasses at room temperature

    Science.gov (United States)

    Peng, Mingying; Zollfrank, Cordt; Wondraczek, Lothar

    2009-07-01

    Bi-doped glasses with broadband photoluminescence in the near-infrared (NIR) spectral range are presently receiving significant consideration for potential applications in telecommunications, widely tunable fiber lasers and spectral converters. However, the origin of NIR emission remains disputed. Here, we report on NIR absorption and emission properties of bismuthate glass and their dependence on the melting temperature. Results clarify that NIR emission occurs from the same centers as it does in Bi-doped glasses. The dependence of absorption and NIR emission of bismuthate glasses on the melting temperature is interpreted as thermal dissociation of Bi2O3 into elementary Bi. Darkening of bismuthate glass melted at 1300 °C is due to the agglomeration of Bi atoms. The presence of Bi nanoparticles is confirmed by transmission electron microscopy, high-resolution energy dispersive x-ray spectroscopy and element distribution mapping. By adding antimony oxide as an oxidation agent to the glass, NIR emission centers can be eliminated and Bi3+ is formed. By comparing with atomic spectral data, absorption bands at ~320 , ~500 , 700 , 800 and 1000 nm observed in Bi-doped glasses are assigned to Bi0 transitions {}^{4}\\mathrm {S_{3/2}} \\to {}^{2}\\mathrm {P_{3/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {P_{1/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{5/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{3/2}}(2) and {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{3/2 }}(1) , respectively, and broadband NIR emission is assigned to the transition {}^{2}\\mathrm {D_{3/2}(1)}\\to {}^{4}\\mathrm {S_{3/2}} .