WorldWideScience

Sample records for chalcogenide minerals dta-tg

  1. Study of the mechanism of andalusite-Al°-N2 reaction using the combination of DTA-TG-DTG techniques Estudo do mecanismo da reação andalusita-Al°-N2 usando a combinação das técnicas ATD-ATG-TGD

    Directory of Open Access Journals (Sweden)

    A. D. Mazzoni

    1999-06-01

    Full Text Available Alumina based ceramics have important engineering applications due to their good physicochemical properties but their performance may be enhanced by addition of a second phase. Aluminosilicates as andalusite submitted to aluminium reduction and the simultaneous nitriding (N2 atmosphere leads to the obtention of alumina and phases of the Si-Al-O-N system. These phases are of great interest for structural ceramics. Mixes prepared with andalusite and Al° (different content were treated with N2 up to 1550 °C., using a heating rate of 5 °/min. Thermal effects (DTA and weight changes (TG, DTG of nitriding reactions during heating were evaluated. The reaction mechanism was determined using DTA-TG-DTG techniques. Results indicate that Si° and AlN are important intermediate phases during reactions. The final products were a-Al2O3 with sialons, mainly b’ phase and polytype sialons. The final formed phases depend on the Al° content and can be predicted using the Si-Al-O-N phase diagram.Cerâmicas à base de alumina apresentam importantes aplicações em engenharia por causa de suas boas propriedades físico-químicas; entretanto, seu desempenho pode ser melhorado pela adição de uma segunda fase. Aluminosilicatos tais como andalusita submetida a redução do alumínio e simultânea nitretação ( atmosfera de N2 leva a obtenção de alumina e fases do sistema Si-Al-O-N. Essas fases são de graande interesse em cerâmica estrutural. Misturas preparadas com andalusita e Al° (teor diferente foram tratadas com N2 até 1550° C, com taxa de aquecimento de 5° /min. Os efeitos térmicos (ATD e variações de massa (TG, DTG das reações de nitretação durante aquecimento foram determinados. O mecanismo da reação foi determinado usando as técnicas ATD-ATG-DTG. Os resultados mostram que Si° e AlN são fases intermediárias importantes durante as reações. Os produtos finais foram a-Al2O3 com sialons, principalmente a faseb’ e sialons politipos. As

  2. Chalcogenide Fibre Displacement Sensor

    Science.gov (United States)

    2001-06-01

    Fibre optic technology offers the possibility for developing of a variety of physical sensors for a wide range of physical parameters. The main...integrating sphere. The use of chalcogenide rather quartz fibre optic highly increases the Sensitivity of the sensor. Experimental set-up, transmission characteristics and technical parameters are presented.

  3. Chalcogenide perovskites for photovoltaics.

    Science.gov (United States)

    Sun, Yi-Yang; Agiorgousis, Michael L; Zhang, Peihong; Zhang, Shengbai

    2015-01-14

    Chalcogenide perovskites are proposed for photovoltaic applications. The predicted band gaps of CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 with the distorted perovskite structure are within the optimal range for making single-junction solar cells. The predicted optical absorption properties of these materials are superior compared with other high-efficiency solar-cell materials. Possible replacement of the alkaline-earth cations by molecular cations, e.g., (NH3NH3)(2+), as in the organic-inorganic halide perovskites (e.g., CH3NH3PbI3), are also proposed and found to be stable. The chalcogenide perovskites provide promising candidates for addressing the challenging issues regarding halide perovskites such as instability in the presence of moisture and containing the toxic element Pb.

  4. Hierarchical Architecturing for Layered Thermoelectric Sulfides and Chalcogenides

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    Priyanka Jood

    2015-03-01

    Full Text Available Sulfides are promising candidates for environment-friendly and cost-effective thermoelectric materials. In this article, we review the recent progress in all-length-scale hierarchical architecturing for sulfides and chalcogenides, highlighting the key strategies used to enhance their thermoelectric performance. We primarily focus on TiS2-based layered sulfides, misfit layered sulfides, homologous chalcogenides, accordion-like layered Sn chalcogenides, and thermoelectric minerals. CS2 sulfurization is an appropriate method for preparing sulfide thermoelectric materials. At the atomic scale, the intercalation of guest atoms/layers into host crystal layers, crystal-structural evolution enabled by the homologous series, and low-energy atomic vibration effectively scatter phonons, resulting in a reduced lattice thermal conductivity. At the nanoscale, stacking faults further reduce the lattice thermal conductivity. At the microscale, the highly oriented microtexture allows high carrier mobility in the in-plane direction, leading to a high thermoelectric power factor.

  5. Chalcogenide Glass for Passive Infrared Applications

    Institute of Scientific and Technical Information of China (English)

    Xianghua Zhang; Hongli Ma; Jacques Lucas

    2003-01-01

    Chalcogenide glass fibers have been successfully used for remote spectroscopy, temperature sensing and CO2 laser power delivery. In bulk form, chalcogenide glass is the most promising candidate for replacing the expensive germanium lenses for thermal imaging.

  6. Chalcogenide glass hollow core microstructured optical fibers

    Science.gov (United States)

    Shiryaev, Vladimir S.

    2015-03-01

    The recent developments on chalcogenide glass hollow core microstructured optical fibers (HC-MOFs) are presented. The comparative analysis of simulated optical properties for chalcogenide HC-MOFs of negative-curvature with different size and number of capillaries is given. The technique for the manufacture of microstructured chalcogenide preforms, which includes the assembly of the substrate glass tube and 8-10 capillaries, is described. Further trends to improve the optical transmission in chalcogenide NCHCFs are considered.

  7. Superconductivity in Fe-chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.C.; Chen, T.K. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Lee, W.C. [Department of Physics, Applied Physics, and Astronomy, Binghamton University – SUNY (United States); Lin, P.H. [National Synchrotron Research Center, Hsinchu, Taiwan (China); Wang, M.J. [Institute of Astrophysics and Astronomy, Academia Sinica, Taipei, Taiwan (China); Wen, Y.C. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Wu, P.M. [Deparment of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA (United States); Wu, M.K., E-mail: mkwu@mail.ndhu.edu.tw [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); National Donghwa University, Hualien, Taiwan (China)

    2015-07-15

    FeSe, which has the simplest crystal structure among the Fe based superconductors, and related chalcogenide superconductors are ideal candidates for investigating the detailed mechanism of the iron-based superconductors. Here, we summarize recent studies on the Fe-chalcogenides, with the goal to address some unresolved questions such as what is the influence of chemical stoichiometry on the phase diagram, what is the exact parent phase of FeSe system, and why can T{sub c}s be so dramatically enhanced in FeSe based superconductors? Recent developments in novel synthesis to prepare chalcogenide crystals, nano-materials and thin films allow the community to begin to address these issues. Then we review physical properties of the Fe chalcogenides, specifically focusing on optical properties, scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy (ARPES) results. These measurements along with recent theories provide a framework for better understanding the origin of superconductivity in FeSe and Fe-chalcogenides.

  8. Search For Past Life On Mars: Physical And Chemical Characterization Of Calcite Minerals Of Biotic And Abiotic Origin

    Science.gov (United States)

    Stalport, Fabien; Coll, P.; Cabane, M.; Person, A.; Navarro-Gonzales, R.; Raulin, F.; Valay, M.; Ausset, P.; Szopa, C.; McKay, C. P.

    2006-09-01

    Several lines of evidence suggest that early Mars once had liquid water on its surface, a denser atmosphere and a mild climate. Similar environmental conditions led to the origin of life on the Earth more than 3.5 billion years ago; consequently, life might also have originated on Mars. We contend that inorganic compounds could give us interesting clues as to the existence of possible biological activity in future astrobiological missions to Mars. Consequently, we have investigated the physical and chemical properties of calcite, which could be expected on Mars because liquid water was certainly present on the surface of early Mars and carbon dioxide was abundant in its atmosphere. Calcite is interesting because on Earth this mineral is produced by abiotic processes as well as by biological activity. One may suppose that crystalline defects and trace element in the crystal lattice and the growth speed of biotic calcites must indicate a difference between them and pure abiotic calcites. We investigated twelve different terrestrial calcite samples from various origins: biotic, diagenetic and abiotic. The minerals were studied by X-ray diffraction and electron scanning microscopy to determine their mineralogical and chemical composition, and differential thermal analysis coupled to thermogravimetric analysis (DTA-TG) to determine their thermal behavior. Our results show that the thermal degradation of abiotic calcite starts at a temperature at least 40°C higher than the degradation temperature of any biotic calcite investigated. Consequently, in the case of a Martian in-situ study or in a sample return mission, the analysis of Martian minerals by DTA-TG represents a promising approach to detect evidence of past biological activity on Mars.

  9. Search for past life on Mars: Physical and chemical characterization of minerals of biotic and abiotic origin: part 1 - Calcite

    Science.gov (United States)

    Stalport, Fabien; Coll, Patrice; Cabane, Michel; Person, Alain; González, Rafael Navarro; Raulin, Francois; Vaulay, Marie Jo; Ausset, Patrick; McKay, Chris P.; Szopa, Cyril; Zarnecki, John

    2005-12-01

    Several lines of evidence suggest that early Mars once had liquid water on its surface, a denser atmosphere and a mild climate. Similar environmental conditions led to the origin of life on the Earth more than 3.5 billion years ago; consequently, life might also have originated on Mars. The Viking landers searched for evidence of organic molecules on the surface of Mars, and found that the Martian soil is depleted in organics at ppb levels at the landing sites. We contend that inorganic compounds could give us interesting clues as to the existence of possible biological activity in future astrobiological missions to Mars. Consequently, we have investigated the physical and chemical properties of calcite, which could be expected on Mars because liquid water was certainly present on the surface of early Mars and carbon dioxide was abundant in its atmosphere. Calcite is interesting because on Earth this mineral is produced by abiotic processes as well as by biological activity. One may suppose that crystalline defects and trace element in the crystal lattice and the growth speed of biotic calcites must indicate a difference between them and pure abiotic calcites. We investigated twelve different terrestrial calcite samples from various origins: biotic, diagenetic and abiotic. The minerals were studied by X-ray diffraction and electron scanning microscopy to determine their mineralogical and chemical composition, and differential thermal analysis coupled to thermogravimetric analysis (DTA-TG) to determine their thermal behavior. Our results show that the thermal degradation of abiotic calcite starts at a temperature at least 40°C higher than the degradation temperature of any biotic calcite investigated. Consequently, in the case of a Martian in-situ study or in a sample return mission, the analysis of Martian minerals by DTA-TG represents a promising approach to detect evidence of past biological activity on Mars.

  10. [Study on the influence of mineralizer on the structures and spectral properties of calcium aluminates].

    Science.gov (United States)

    Zheng, Huai-Li; Liu, Jun-Yu; Li, Lin-Tao; Li, Fang

    2009-11-01

    The present paper investigated the effect of mineralizer on the structure and properties of calcium aluminates formation. Calcium aluminates powder was synthesized under high temperature calcination by mixing bauxite, limestone and a certain amount of mineralizer. The product structure, compositional information and spectral properties were carefully characterized by XRD, IR and DTA-TG, and the mineralization mechanism of mineralizer was studied during the process of calcium aluminates preparation. The results showed that calcium aluminates powder could be obtained under lower temperature calcination after adding mineralizer to the raw materials. The main products of the reaction were CaAl10 O18 and CaAl2 Si2 O8 without mineralizer, however, the main products of the reaction were CaAl3 BO7 and Ca3 Al10 O18 with mineralizer, in which Al2 O3s could be extracted easily, while CaAl2 Si2 O8 was reduced greatly in which Al2 O3 could not be extracted easily. At the same time, it is easy for calcspar to decompose after adding mineralizer. It is favorable to Al-Si bond break and Al stripping from bauxite. These facts could improve the extraction rate of Al2 O3 from raw materials. Also, in the case of adding mineralizer to the raw mixes, the crystal structure and composition are changed, which is beneficial to reducing calcination temperature.

  11. Noble-Metal Chalcogenide Nanotubes

    Directory of Open Access Journals (Sweden)

    Nourdine Zibouche

    2014-10-01

    Full Text Available We explore the stability and the electronic properties of hypothetical noble-metal chalcogenide nanotubes PtS2, PtSe2, PdS2 and PdSe2 by means of density functional theory calculations. Our findings show that the strain energy decreases inverse quadratically with the tube diameter, as is typical for other nanotubes. Moreover, the strain energy is independent of the tube chirality and converges towards the same value for large diameters. The band-structure calculations show that all noble-metal chalcogenide nanotubes are indirect band gap semiconductors. The corresponding band gaps increase with the nanotube diameter rapidly approaching the respective pristine 2D monolayer limit.

  12. Minerals

    Directory of Open Access Journals (Sweden)

    Vaquero, M. P.

    1998-08-01

    Full Text Available The possible changes in the mineral composition of food during frying could be the consequence of losses by leaching, or changes in concentrations caused by exchanges between the food and culinary fat of other compounds. The net result depends on the type of food, the frying fat used and the frying process. Moreover, the modifications that frying produces in other nutrients could indirectly affect the availability of dietary minerals. The most outstanding ones are those that can take place in the fat or in the protein. With respect to the interactions between frying oils and minerals, we have recent knowledge concerning the effects of consuming vegetable oils used in repeated fryings of potatoes without turnover, on the nutritive utilization of dietary minerals. The experiments have been carried out in pregnant and growing rats, which consumed diets containing, as a sole source of fat, the testing frying oils or unused oils. It seems that the consumption of various frying oils, with a polar compound content lower or close to the maximum limit of 25% accepted for human consumption, does not alter the absorption and metabolism of calcium, phosphorous, iron or copper. Magnesium absorption from diets containing frying oils tends to increase but the urinary excretion of this element increases, resulting imperceptible the variations in the magnesium balance. The urinary excretion of Zn also increased although its balance remained unchanged. Different studies referring to the effects of consuming fried fatty fish on mineral bioavailability will also be presented. On one hand, frying can cause structural changes in fish protein, which are associated with an increase in iron absorption and a decrease in body zinc retention. The nutritive utilization of other elements such as magnesium, calcium and copper seems to be unaffected. On the other hand; it has been described that an excess of fish fatty acids in the diet produces iron depletion, but when fatty

  13. Nonlinear Integrated Optical Waveguides in Chalcogenide Glasses

    Institute of Scientific and Technical Information of China (English)

    Yinlan; Ruan; Barry; Luther-Davies; Weitang; Li; Andrei; Rode; Marek; Samoc

    2003-01-01

    This paper reports on the study and measurement of the third order optical nonlinearity in bulk sulfide-based chalcogenide glasses; The fabrication process of the ultrafast laser deposited As-S-(Se)-based chalcogenide films and optical waveguides using two techniques: wet chemistry etching and plasma etching.

  14. Method to synthesize metal chalcogenide monolayer nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Sanchez, Bernadette A.; Boyle, Timothy J.

    2016-12-13

    Metal chalcogenide monolayer nanomaterials can be synthesized from metal alkoxide precursors by solution precipitation or solvothermal processing. The synthesis routes are more scalable, less complex and easier to implement than other synthesis routes.

  15. Metastable states in amorphous chalcogenide semiconductors

    CERN Document Server

    Mikla, Victor I

    2009-01-01

    This book addresses an interesting and technologically important class of materials, the amorphous chalcogenide semiconductors. Experimental results on the structural and electronic metastable states in Se-rich chalcogenides are presented. Special attention is paid to the states in the mobility gap and their sensitivity to various factors such as irradiation, annealing and composition. Photoinduced changes of structure and physical properties are also considered and structural transformation at photocrystallization is studied in detail. Finally, the authors discuss potential applications of th

  16. Metal chalcogenide nanostructures for renewable energy applications

    CERN Document Server

    Qurashi, Ahsanulhaq

    2014-01-01

    This first ever reference book that focuses on metal chalcogenide semiconductor nanostructures for renewable energy applications encapsulates the state-of-the-art in multidisciplinary research on the metal chalcogenide semiconductor nanostructures (nanocrystals, nanoparticles, nanorods, nanowires,  nanobelts, nanoflowers, nanoribbons and more).  The properties and synthesis of a class of nanomaterials is essential to renewable energy manufacturing and this book focuses on the synthesis of metal chalcogendie nanostructures, their growth mechanism, optical, electrical, and other important prop

  17. Chalcogenide Nanoionic-based Radio Frequency Switch

    Science.gov (United States)

    Nessel, James (Inventor); Lee, Richard (Inventor)

    2013-01-01

    A nonvolatile nanoionic switch is disclosed. A thin layer of chalcogenide glass engages a substrate and a metal selected from the group of silver and copper photo-dissolved in the chalcogenide glass. A first oxidizable electrode and a second inert electrode engage the chalcogenide glass and are spaced apart from each other forming a gap therebetween. A direct current voltage source is applied with positive polarity applied to the oxidizable electrode and negative polarity applied to the inert electrode which electrodeposits silver or copper across the gap closing the switch. Reversing the polarity of the switch dissolves the electrodeposited metal and returns it to the oxidizable electrode. A capacitor arrangement may be formed with the same structure and process.

  18. Multimode supercontinuum generation in chalcogenide glass fibres

    DEFF Research Database (Denmark)

    Kubat, Irnis; Bang, Ole

    2016-01-01

    Mid-infrared supercontinuum generation is considered in chalcogenide fibres when taking into account both polarisations and the necessary higher order modes. In particular we focus on high pulse energy supercontinuum generation with long pump pulses. The modeling indicates that when only a single...

  19. Ultra-precision molding of chalcogenide glass aspherical lens

    Science.gov (United States)

    Zhang, Feng; Wang, Zhibin; Zhang, Yunlong; Su, Ying; Guo, Rui; Xu, Zengqi; Liu, Xuanmin

    2016-10-01

    With the development of infrared optical systems in military and civil areas, chalcogenide glass aspherical lens possess some advantages, such as large infrared transmission, good thermal stability performance and image quality. Aspherical lens using chalcogenide glass can satisfy the requirements of modern infrared optical systems. Therefore, precision manufacturing of chalcogenide glass aspheric has received more and more attention. The molding technology of chalcogenide glass aspheric has become a research hotspot, because it can achieve mass and low cost manufacturing. The article of molding technology is focusing on a kind of chalcogenide glass aspherical lens. We report on design and fabrication of the mold that through simulation analysis of molding. Finally, through molding test, the fabrication of mold's surface and parameters of molding has been optimized, ensuring the indicators of chalcogenide glass aspherical lens meet the requirements.

  20. Chalcogenide Glass Optical Waveguides for Infrared Biosensing

    Science.gov (United States)

    Anne, Marie-Laure; Keirsse, Julie; Nazabal, Virginie; Hyodo, Koji; Inoue, Satoru; Boussard-Pledel, Catherine; Lhermite, Hervé; Charrier, Joël; Yanakata, Kiyoyuki; Loreal, Olivier; Le Person, Jenny; Colas, Florent; Compère, Chantal; Bureau, Bruno

    2009-01-01

    Due to the remarkable properties of chalcogenide (Chg) glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared spectral range we have developed a biosensor that can collect information on whole metabolism alterations, rapidly and in situ. Thanks to this sensor it is possible to collect infrared spectra by remote spectroscopy, by simple contact with the sample. In this way, we tried to determine spectral modifications due, on the one hand, to cerebral metabolism alterations caused by a transient focal ischemia in the rat brain and, in the other hand, starvation in the mouse liver. We also applied a microdialysis method, a well known technique for in vivo brain metabolism studies, as reference. In the field of integrated microsensors, reactive ion etching was used to pattern rib waveguides between 2 and 300 μm wide. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films, which can potentially increase the sensitivity and stability of an optical micro-sensor. The first tests were also carried out to functionalise the Chg planar waveguides with the aim of using them as (bio)sensors. PMID:22423209

  1. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

    DEFF Research Database (Denmark)

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass ...

  2. Physics and chemistry review of layered chalcogenide superconductors

    OpenAIRE

    Deguchi, Keita; Takano, Yoshihiko; Mizuguchi, Yoshikazu

    2012-01-01

    Structural and physical properties of layered chalcogenide superconductors are summarized. In particular, we review the remarkable properties of the Fe-chalcogenide superconductors, FeSe and FeTe-based materials. Furthermore, we introduce the recently-discovered new BiS2-based layered superconductors and discuss its prospects.

  3. The Synthesis and Physical Properties of Magnesium Borate Mineral of Admontite Synthesized from Sodium Borates

    Directory of Open Access Journals (Sweden)

    Azmi Seyhun Kipcak

    2014-01-01

    Full Text Available Magnesium borates are significant compounds due to their advanced mechanical and thermal durability properties. This group of minerals can be used in ceramic industry, in detergent industry, and as neutron shielding material, phosphor of thermoluminescence by dint of their extraordinary specialties. In the present study, the synthesis of magnesium borate via hydrothermal method from sodium borates and physical properties of synthesized magnesium borate minerals were investigated. The characterization of the products was carried out by X-ray diffraction (XRD, Fourier transform infrared (FT-IR and Raman spectroscopies, and differential thermal analysis and thermal gravimetry (DTA/TG. The surface morphology was examined by scanning electron microscopy (SEM. B2O3 content was determined through titration. The electrical resistivity/conductivity properties of products were measured by Picoammeter Voltage Source. UV-vis spectrometer was used to investigate optical absorption characteristics of synthesized minerals in the range 200–1000 nm at room temperature. XRD results identified the synthesized borate minerals as admontite [MgO(B2O33·7(H2O] with code number “01-076-0540” and mcallisterite [Mg2(B6O7(OH62·9(H2O] with code number “01-070-1902.” The FT-IR and Raman spectra of the obtained samples were similar with characteristic magnesium borate bands. The investigation of the SEM images remarked that both nano- and microscale minerals were produced. The reaction yields were between 75.1 and 98.7%.

  4. Synthesis and structures of metal chalcogenide precursors

    Science.gov (United States)

    Hepp, Aloysius F.; Duraj, Stan A.; Eckles, William E.; Andras, Maria T.

    1990-01-01

    The reactivity of early transition metal sandwich complexes with sulfur-rich molecules such as dithiocarboxylic acids was studied. Researchers recently initiated work on precursors to CuInSe2 and related chalcopyrite semiconductors. Th every high radiation tolerance and the high absorption coefficient of CuInSe2 makes this material extremely attractive for lightweight space solar cells. Their general approach in early transition metal chemistry, the reaction of low-valent metal complexes or metal powders with sulfur and selenium rich compounds, was extended to the synthesis of chalcopyrite precursors. Here, the researchers describe synthesis, structures, and and routes to single molecule precursors to metal chalcogenides.

  5. Chemical Routes to Colloidal Chalcogenide Nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Schaak, Raymond

    2015-02-19

    This project sought to develop new low-temperature synthetic pathways to intermetallic and chalcogenide nanostructures and powders, with an emphasis on systems that are relevant to advancing the synthesis, processing, and discovery of superconducting materials. The primary synthetic routes involved solution chemistry methods, and several fundamental synthetic challenges that underpinned the formation of these materials were identified and investigated. Methods for incorporating early transition metals and post transition metals into nanoscale and bulk crystals using low-temperature solution chemistry methods were developed and studied, leading to colloidal nanocrystals of elemental indium, manganese, and germanium, as well as nanocrystalline and bulk intermetallic compounds containing germanium, gallium, tin, indium, zinc, bismuth, and lithium. New chemical tools were developed to help target desired phases in complex binary intermetallic and metal chalcogenide systems that contain multiple stable phases, including direct synthesis methods and chemical routes that permit post-synthetic modification. Several phases that are metastable in bulk systems were targeted, synthesized, and characterized as nanocrystalline solids and bulk powders, including the L12-type intermetallic compounds Au3Fe, Au3Ni, and Au3Co, as well as wurtzite-type MnSe. Methods for accessing crystalline metal borides and carbides using direct solution chemistry methods were also developed, with an emphasis on Ni3B and Ni3C, which revealed useful correlations of composition and magnetic properties. Methods for scale-up and nanoparticle purification were explored, providing access to centimeter-scale pressed pellets of polyol-synthesized nanopowders and a bacteriophage-mediated method for separating impure nanoparticle mixtures into their components. Several advances were made in the synthesis of iron selenide and related superconducting materials, including the production of colloidal Fe

  6. Summary of Chalcogenide Glass Processing: Wet-Etching and Photolithography

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Sundaram, S. K.; Johnson, Bradley R.; Saraf, Laxmikant V.

    2006-12-01

    This report describes a study designed to explore the different properties of two different chalcogenide materials, As2S3 and As24S38Se38, when subjected to photolithographic wet-etching techniques. Chalcogenide glasses are made by combining chalcogen elements S, Se, and Te with Group IV and/or V elements. The etchant was selected from the literature and was composed of sodium hydroxide, isopropyl alcohol, and deionized water and the types of chalcogenide glass for study were As2S3 and As24S38Se38. The main goals here were to obtain a single variable etch rate curve of etch depth per time versus NaOH overall solution concentration in M and to see the difference in etch rate between a given etchant when used on the different chalcogenide stoichiometries. Upon completion of these two goals, future studies will begin to explore creating complex, integrated photonic devices via these methods.

  7. Radiation-induced defect formation in chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.I.; Filipecki, J. [Physics Institute of Pedagogical University of Czestochowa, Al. Armii Krajowej 13/15, Czestochowa 42201 (Poland); Kozdras, A. [Physics Laboratory of Opole Technical University, 75 ul. Ozimska, Opole, PL-45370 (Poland); Kavetskyy, T.S. [Lviv Scientific Research Institute of Materials of Scientific Research Company ' Carat' , Stryjska Str. 202, Lviv, UA-79031 (Ukraine)

    2003-10-01

    The modified model of native and radiation-induced microvoid-type positron traps in vitreous chalcogenide semiconductors is developed to explain compositional features of positron annihilation lifetime measurements in stoichiometric As{sub 2}S{sub 3}-GeS{sub 2} and non-stoichiometric As{sub 2}S{sub 3}-Ge{sub 2}S{sub 3} chalcogenide glasses before and after {gamma}-irradiation.

  8. Debye temperatures of uranium chalcogenides from their lattice dynamics

    Indian Academy of Sciences (India)

    S Durai; P Babu

    2005-12-01

    Phonon dispersion relations in uranium chalcogenides have been investigated using a modified three-body force shell model. From the phonon frequencies, their Debye temperatures are evaluated. Further, on the basis of the spin fluctuation in the heavy fermion uranium compounds, UPt3 and UBe13, the possible superconducting transition temperatures of chalcogenides are theoretically predicted. The c values are in the same range as of those in UPt3 and UBe13.

  9. Electrochemical Synthesis and Characterization of Nanostructured Chalcogenide Materials

    OpenAIRE

    Chang, Chong Hyun

    2011-01-01

    Nanostructured materials have attracted extensive attention due to their small dimension and enhanced properties compared to bulk materials, and their large range of potential applications in energy harvesting devices. Among these materials, nanostructured chalcogenides play an important role in thermoelectric and solar cell devices. Electrochemical techniques have drawn attention as an improved method for synthesizing nanostructured chalcogenide materials, since they provide a cost-effective...

  10. Demonstration of chalcogenide glass racetrack microresonators.

    Science.gov (United States)

    Hu, Juejun; Carlie, Nathan; Petit, Laeticia; Agarwal, Anu; Richardson, Kathleen; Kimerling, Lionel

    2008-04-15

    We have demonstrated what we believe to be the first chalcogenide glass racetrack microresonator using a complementary metal-oxide semiconductor-compatible lift-off technique with thermally evaporated As(2)S(3) films. The device simultaneously features a small footprint of 0.012 mm x 0.012 mm, a cavity Q (quality factor) of 10,000, and an extinction ratio of 32 dB. These resonators exhibit a very high sensitivity to refractive index changes with a demonstrated detection capability of Dn(As(2)S(3)=(4.5 x 10(-6)+/-10%) refractive index unit. The resonators were applied to derive a photorefractive response of As(2)S(3) to lambda=550 nm light. The resonator devices are a versatile platform for both sensing and glass material property investigation.

  11. Chalcogenide glass hollow core photonic crystal fibers

    Science.gov (United States)

    Désévédavy, Frédéric; Renversez, Gilles; Troles, Johann; Houizot, Patrick; Brilland, Laurent; Vasilief, Ion; Coulombier, Quentin; Traynor, Nicholas; Smektala, Frédéric; Adam, Jean-Luc

    2010-09-01

    We report the first hollow core photonic crystal fibers (HC PCF) in chalcogenide glass. To design the required HC PCF profiles for such high index glass, we use both band diagram analysis to define the required photonic bandgap and numerical simulations of finite size HC PCFs to compute the guiding losses. The material losses have also been taken into account to compute the overall losses of the HC PCF profiles. These fibers were fabricated by the stack and draw technique from TeAsSe (TAS) glass. The fibers we drew in this work are composed of six rings of holes and regular microstructures. Two profiles are presented, one is known as a kagome lattice and the other one corresponds to a triangular lattice. Geometrical parameters are compared to the expected parameters obtained by computation. Applications of such fibers include power delivery or fiber sensors among others.

  12. Solution-processing of chalcogenide materials for device applications

    Science.gov (United States)

    Zha, Yunlai

    Chalcogenide glasses are well-known for their desirable optical properties, which have enabled many infrared applications in the fields of photonics, medicine, environmental sensing and security. Conventional deposition methods such as thermal evaporation, chemical vapor deposition, sputtering or pulse laser deposition are efficient for fabricating structures on flat surfaces. However, they have limitations in deposition on curved surfaces, deposition of thick layers and component integration. In these cases, solution-based methods, which involve the dissolution of chalcogenide glasses and processing as a liquid, become a better choice for their flexibility. After proper treatment, the associated structures can have similar optical, chemical and physical properties to the bulk. This thesis presents an in-depth study of solution-processing chalcogenide glasses, starting from the "solution state" to the "film state" and the "structure state". Firstly, chalcogenide dissolution is studied to reveal the mechanisms at molecular level and build a foundation for material processing. Dissolution processes for various chalcogenide solvent pairs are reviewed and compared. Secondly, thermal processing, in the context of high temperature annealing, is explained along with the chemical and physical properties of the annealed films. Another focus is on nanopore formation in propylamine-processed arsenic sulfide films. Pore density changes with respect to annealing temperatures and durations are characterized. Base on a proposed vacancy coalescence theory, we have identified new dissolution strategies and achieved the breakthrough of pore-free film deposition. Thirdly, several solution methods developed along with the associated photonic structures are demonstrated. The first example is "spin-coating and lamination", which produces thick (over 10 mum) chalcogenide structures. Both homogeneous thick chalcogenide structures and heterogeneous layers of different chalcogenide glasses

  13. Optical Nonlinearities in Chalcogenide Glasses and their Applications

    CERN Document Server

    Zakery, A

    2007-01-01

    Photonics, which uses photons for information and image processing, has been labeled the technology of the 21st century, for which non-linear optical processes provide the key functions of frequency conversion and optical switching. Chalcogenide glass fiber is one of the most promising candidates for use as a non-linear optical medium because of its high optical nonlinearity and long interaction length. Since the chalcogenide glass fibers transmit into the IR, there are numerous potential applications in the civil, medical and military areas. One of the most exciting developments in the future is going to be in the area of rare-earth ion doping of chalcogenide fibers for IR fluorescence emission. The IR light sources, lasers and amplifiers developed using this phenomena will be very useful in civil, medical and military applications. Remote IR spectroscopy and imaging using flexible fibers will be realized for applications. Other future research areas which will inevitably be explored includes non-linear opti...

  14. Nonlinear optical localization in embedded chalcogenide waveguide arrays

    Directory of Open Access Journals (Sweden)

    Mingshan Li

    2014-05-01

    Full Text Available We report the nonlinear optical localization in an embedded waveguide array fabricated in chalcogenide glass. The array, which consists of seven waveguides with circularly symmetric cross sections, is realized by ultrafast laser writing. Light propagation in the chalcogenide waveguide array is studied with near infrared laser pulses centered at 1040 nm. The peak intensity required for nonlinear localization for the 1-cm long waveguide array was 35.1 GW/cm2, using 10-nJ pulses with 300-fs pulse width, which is 70 times lower than that reported in fused silica waveguide arrays and with over 7 times shorter interaction distance. Results reported in this paper demonstrated that ultrafast laser writing is a viable tool to produce 3D all-optical switching waveguide circuits in chalcogenide glass.

  15. Electronic-structure calculations of large cadmium chalcogenide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Frenzel, Johannes [Lehrstuhl fuer Theoretische Chemie, Ruhr-Universitaet Bochum (Germany); Joswig, Jan-Ole [Physikalische Chemie, Technische Universitaet Dresden (Germany)

    2012-02-15

    In this paper, we will review our studies of large cadmium chalcogenide nanoparticles and present some new results on cadmium telluride systems. All calculations have been performed using density-functional based methods. The studies deal with the structural properties of saturated and unsaturated nanoparticles where the surfactants generally are hydrogen atoms or thiol groups. We have focused on the investigation of the density of states, the Mulliken charges, the eigenvalue spectra, and the spatial distributions of the frontier orbitals. Optical excitation spectra of pure CdS and CdSe/CdS core-shell systems have been calculated using a linear-response formalism. The reviewed studies are compared to the state of the art of modeling large cadmium chalcogenide particles. Optical excitations in large saturated cadmium chalcogenide nanoparticles with several thousand atoms. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Effect of pressure on the phonon properties of europium chalcogenides

    Indian Academy of Sciences (India)

    U K Sakalle; P K Jha; S P Sanyal

    2000-06-01

    Lattice vibrational properties of europium chalcogenides have been investigated at high pressure by using a simple lattice dynamical model theory viz. the three-body force rigid ion model (TRIM) which includes long range three-body interaction arising due to charge transfer effects. The dispersion curves for the four Eu-chalcogenides agree reasonably well with the available experimental data. Variation of LO, TO, LA and TA phonons with pressure have also been studied at the symmetry points of the brillouin zone (BZ) for Euchalcogenides for the first time by using a lattice dynamical model theory. We have also calculated the one phonon density of states and compared them with the first order Raman scattering results. The calculation of one phonon density of states for Eu-chalcogenides has also been extended up to the phase transition pressure. We observed a pronounced shift in phonon spectrum as pressure is increased.

  17. High surface area graphene-supported metal chalcogenide assembly

    Science.gov (United States)

    Worsley, Marcus A.; Kuntz, Joshua; Orme, Christine A.

    2016-04-19

    A composition comprising at least one graphene-supported assembly, which comprises a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds, and at least one metal chalcogenide compound disposed on said graphene sheets, wherein the chalcogen of said metal chalcogenide compound is selected from S, Se and Te. Also disclosed are methods for making and using the graphene-supported assembly, including graphene-supported MoS.sub.2. Monoliths with high surface area and conductivity can be achieved. Lower operating temperatures in some applications can be achieved. Pore size and volume can be tuned.

  18. Mid infrared supercontinuum generation from chalcogenide glass waveguides and fibers

    DEFF Research Database (Denmark)

    Luther-Davies, Barry; Yu, Yi; Zhang, Bin;

    2015-01-01

    I report work on mid-infrared super-continuum generation in chalcogenide fibers and waveguides pumped by 320fsec pulses at 21MHz in the 3-4.6µm range. Average powers of ≈20mW were produced with spectral coverage from <2µm to >11µm.......I report work on mid-infrared super-continuum generation in chalcogenide fibers and waveguides pumped by 320fsec pulses at 21MHz in the 3-4.6µm range. Average powers of ≈20mW were produced with spectral coverage from 11µm....

  19. Recent Advances in Layered Metal Chalcogenides as Superconductors and Thermoelectric Materials: Fe-Based and Bi-Based Chalcogenides.

    Science.gov (United States)

    Mizuguchi, Yoshikazu

    2016-04-01

    Recent advances in layered (Fe-based and Bi-based) chalcogenides as superconductors or functional materials are reviewed. The Fe-chalcogenide (FeCh) family are the simplest Fe-based high-Tc superconductors. The superconductivity in the FeCh family is sensitive to external or chemical pressure, and high Tc is attained when the local structure (anion height) is optimized. The Bi-chalcogenide (BiCh2) family are a new group of layered superconductors with a wide variety of stacking structures. Their physical properties are also sensitive to external or chemical pressure. Recently, we revealed that the emergence of superconductivity and the Tc in this family correlate with the in-plane chemical pressure. Since the flexibility of crystal structure and electronic states are an advantage of the BiCh2 family for designing functionalities, I briefly review recent developments in this family as not only superconductors but also other functional materials.

  20. On the instability effects in radiation-sensitive chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, V. [Lviv State University for Vital Activity Safety, 35 Kleparivska str., Lviv, UA-79007 (Ukraine); Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Kovalskiy, A. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)], E-mail: shpotyuk@novas.lviv.ua; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)

    2007-04-15

    The features of application of radiation-sensitive media based on chalcogenide glasses of As-Ge-S system for registration of high-energy {gamma}-radiation are analysed. It is shown that compositional features of the observed time-instability effect should be taken into account in order to ensure a higher accuracy of the developed dosimeters.

  1. Ultrafast Laser Fabrication of Bragg Waveguides in GLS Chalcogenide Glass

    Directory of Open Access Journals (Sweden)

    McMillen Ben

    2013-11-01

    Full Text Available We present work on the fabrication of Bragg waveguides in gallium-lanthanum-sulfide chalcogenide glass using an ultrafast laser. Waveguides were written with a single pass while modulating the writing beam. The spatial and temporal profile of the writing beam was ontrolled during waveguide fabrication in order to control the shape and size of the waveguide cross-section.

  2. Chalcogenide microstructured optical fibres for mid-IR applications

    Science.gov (United States)

    Trolès, Johann; Brilland, Laurent

    2017-01-01

    Compared to oxide-based glasses, vitreous materials composed of chalcogen elements (S, Se, Te) show large transparency windows in the infrared. Indeed, chalcogenide glasses can be transparent from the visible up to 12- 18 μm, depending on their compositions. In addition, chalcogenide glasses contain large polarisable atoms and external lone electron pairs that induce exceptional non-linear properties. Consequently, the non-linear properties can be 100 or 1000 times as high as the non-linearity of silica. An original way to obtain single-mode fibres is to design microstructured optical fibres (MOFs). These fibres present unique optical properties thanks to the high degree of freedom in the design of their geometrical structure. Various chalcogenide MOFs operating in the IR range have been elaborated in order to associate the high non-linear properties of these glasses with the original MOF properties. Indeed, chalcogenide MOFs might lead to new devices with unique optical properties in the mid-infrared domain, like multimode or endlessly single-mode transmission of light, small or large mode area fibres, highly birefringent fibres and non-linear properties for wavelength conversion or generation of supercontinuum sources. xml:lang="fr"

  3. Magnetic excitations in iron chalcogenide superconductors.

    Science.gov (United States)

    Kotegawa, Hisashi; Fujita, Masaki

    2012-10-01

    Nuclear magnetic resonance and neutron scattering experiments in iron chalcogenide superconductors are reviewed to make a survey of the magnetic excitations in FeSe, FeSe1-x Te x and alkali-metal-doped Ax Fe2-y Se2 (A = K, Rb, Cs, etc). In FeSe, the intimate relationship between the spin fluctuations and superconductivity can be seen universally for the variations in the off-stoichiometry, the Co-substitution and applied pressure. The isovalent compound FeTe has a magnetic ordering with different wave vector from that of other Fe-based magnetic materials. The transition temperature Tc of FeSe increases with Te substitution in FeSe1-x Te x with small x, and decreases in the vicinity of the end member FeTe. The spin fluctuations are drastically modified by the Te substitution. In the vicinity of the end member FeTe, the low-energy part of the spin fluctuation is dominated by the wave vector of the ordered phase of FeTe; however, the reduction of Tc shows that it does not support superconductivity. The presence of same wave vector as that of other Fe-based superconductors in FeSe1-x Te x and the observation of the resonance mode demonstrate that FeSe1-x Te x belongs to the same group as most of other Fe-based superconductors in the entire range of x, where superconductivity is mediated by the spin fluctuations whose wave vector is the same as the nesting vector between the hole pockets and the electron pockets. On the other hand, the spin fluctuations differ for alkali-metal-doped Ax Fe2-y Se2 and FeSe or other Fe-based superconductors in their wave vector and strength in the low-energy part, most likely because of the different Fermi surfaces. The resonance mode with different wave vector suggests that Ax Fe2-y Se2 has an exceptional superconducting symmetry among Fe-based superconductors.

  4. Error-free 640 Gbit/s demultiplexing using a chalcogenide planar waveguide chip

    DEFF Research Database (Denmark)

    Xu, Jing; Galili, Michael; Mulvad, Hans Christian Hansen;

    2008-01-01

    We demonstrate error free, low-penalty demultiplexing of a 640 Gbit/s OTDM signal to 10 Gbit/s using a 5cm long chalcogenide planar waveguide chip. Our approach exploits four-wave mixing by the instantaneous nonlinear response of chalcogenide.......We demonstrate error free, low-penalty demultiplexing of a 640 Gbit/s OTDM signal to 10 Gbit/s using a 5cm long chalcogenide planar waveguide chip. Our approach exploits four-wave mixing by the instantaneous nonlinear response of chalcogenide....

  5. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun

    2012-10-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  6. Mold design with simulation for chalcogenide glass precision molding

    Science.gov (United States)

    Zhang, Yunlong; Wang, Zhibin; Li, Junqi; Zhang, Feng; Su, Ying; Wang, Zhongqiang

    2016-10-01

    Compare with the manufacturing of the traditional infrared material, such as signal crystal germanium, zinc sulfide, zinc selenide etc, chalcogenide infrared glass is suitable for precision molding for the low soften temperature to have large mass industry production. So the researches of precision glass molding are necessary, especially for the fast development of infrared product. The mold design is one of the key technologies of precision glass molding. In this paper, the mold processing of a sample chalcogenide glass from the technical drawing, mold design, molding to the lens are introduced. From the result of the precision molding, the technology of finite element simulation is a useful way to guiding the mold design. The molded lens by using mold process fit the design requirement.

  7. Nonlinear light propagation in chalcogenide photonic crystal slow light waveguides.

    Science.gov (United States)

    Suzuki, Keijiro; Baba, Toshihiko

    2010-12-06

    Optical nonlinearity can be enhanced by the combination of highly nonlinear chalcogenide glass and photonic crystal waveguides (PCWs) providing strong optical confinement and slow-light effects. In a Ag-As(2)Se(3) chalcogenide PCW, the effective nonlinear parameter γeff reaches 6.3 × 10(4) W(-1)m(-1), which is 200 times larger than that in Si photonic wire waveguides. In this paper, we report the detailed design, fabrication process, and the linear and nonlinear characteristics of this waveguide at silica fiber communication wavelengths. We show that the waveguide exhibits negligible two-photon absorption, and also high-efficiency self-phase modulation and four-wave mixing, which are assisted by low-dispersion slow light.

  8. Microbial synthesis of chalcogenide semiconductor nanoparticles: a review

    OpenAIRE

    Jacob, Jaya Mary; Lens, Piet N. L.; Balakrishnan, Raj Mohan

    2015-01-01

    Summary Chalcogenide semiconductor quantum dots are emerging as promising nanomaterials due to their size tunable optoelectronic properties. The commercial synthesis and their subsequent integration for practical uses have, however, been contorted largely due to the toxicity and cost issues associated with the present chemical synthesis protocols. Accordingly, there is an immediate need to develop alternative environment‐friendly synthesis procedures. Microbial factories hold immense potentia...

  9. Electronic structure of ruthenium-doped iron chalcogenides

    Science.gov (United States)

    Winiarski, M. J.; Samsel-Czekała, M.; Ciechan, A.

    2014-12-01

    The structural and electronic properties of hypothetical RuxFe1-xSe and RuxFe1-xTe systems have been investigated from first principles within the density functional theory (DFT). Reasonable values of lattice parameters and chalcogen atomic positions in the tetragonal unit cell of iron chalcogenides have been obtained with the use of norm-conserving pseudopotentials. The well known discrepancies between experimental data and DFT-calculated results for structural parameters of iron chalcogenides are related to the semicore atomic states which were frozen in the used here approach. Such an approach yields valid results of the electronic structures of the investigated compounds. The Ru-based chalcogenides exhibit the same topology of the Fermi surface (FS) as that of FeSe, differing only in subtle FS nesting features. Our calculations predict that the ground states of RuSe and RuTe are nonmagnetic, whereas those of the solid solutions RuxFe1-xSe and RuxFe1-xTe become the single- and double-stripe antiferromagnetic, respectively. However, the calculated stabilization energy values are comparable for each system. The phase transitions between these magnetic arrangements may be induced by slight changes of the chalcogen atom positions and the lattice parameters a in the unit cell of iron selenides and tellurides. Since the superconductivity in iron chalcogenides is believed to be mediated by the spin fluctuations in single-stripe magnetic phase, the RuxFe1-xSe and RuxFe1-xTe systems are good candidates for new superconducting iron-based materials.

  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. STUDIES OF CHALCOGENIDE VITREOUS SEMICONDUCTORS IN THE IOFFE PHYSICOTECHNICAL INSTITUTE

    OpenAIRE

    Kolomiets, B.

    1981-01-01

    The broad class of semiconductors discovered at the Ioffe Physical-Technical Institute in 1955-56 [1] and termed at present chalcogenide vitreous semiconductors (ChVS) has recently been attracting ever increasing interest of the researchers due to many properties which are unusual for crystalline semiconductors. During a number of years, our interests here been primarily connected with such basic problems as the transport phenomena, electronic spectrum, the role of impurities, optical and pho...

  12. Local tuning of photonic crystal cavities using chalcogenide glasses

    CERN Document Server

    Faraon, Andrei; Bulla, Douglas; Luther-Davies, Barry; Eggleton, Benjamin J; Stoltz, Nick; Petroff, Pierre; Vuckovic, Jelena

    2007-01-01

    We demonstrate a method to locally change the refractive index in planar optical devices by photodarkening of a thin chalcogenide glass layer deposited on top of the device. The method is used to tune the resonance of GaAs-based photonic crystal cavities by up to 3 nm at 940 nm, with only 5% deterioration in cavity quality factor. The method has broad applications for postproduction tuning of photonic devices.

  13. Chalcogenide material strengthening through the lens molding process

    Science.gov (United States)

    Nelson, J.; Scordato, M.; Lucas, Pierre; Coleman, Garrett J.

    2016-05-01

    The demand for infrared transmitting materials has grown steadily for several decades as markets realize new applications for longer wavelength sensing and imaging. With this growth has come the demand for new and challenging material requirements that cannot be satisfied with crystalline products alone. Chalcogenide materials, with their unique physical, thermal, and optical properties, have found acceptance by designers and fabricators to meet these demands. No material is perfect in every regard, and chalcogenides are no exception. A cause for concern has been the relatively low fracture toughness and the propensity of the bulk material to fracture. This condition is amplified when traditional subtractive manufacturing processes are employed. This form of processing leaves behind micro fractures and sub surface damage, which act as propagation points for both local and catastrophic failure of the material. Precision lens molding is not a subtractive process, and as a result, micro fractures and sub surface damage are not created. This results in a stronger component than one produced by traditional methods. New processing methods have also been identified that result in an even stronger surface that is more resistant to breakage, without the need for post processing techniques that may compromise surface integrity. This paper will discuss results achieved in the process of lens molding development at Edmund Optics that result in measurably stronger chalcogenide components. Various metrics will be examined and data will be presented that quantifies component strength for different manufacturing processes.

  14. Linear and nonlinear optical properties of chalcogenide microstructured optical fibers

    Science.gov (United States)

    Trolès, Johann; Brilland, Laurent; Caillaud, Celine; Renversez, Gilles; Mechin, David; Adam, Jean-Luc

    2015-03-01

    Chalcogenide glasses are known for their large transparency in the mid-infrared and their high linear refractive index (>2). They present also a high non-linear coefficient (n2), 100 to 1000 times larger than for silica, depending on the composition. we have developed a casting method to prepare the microstructured chalcogenide preform. This method allows optical losses as low as 0.4 dB/m at 1.55 µm and less than 0.05 dB/m in the mid IR. Various chalcogenide MOFs operating in the IR range has been fabricated in order to associate the high non-linear properties of these glasses and the original MOF properties. For example, small core fibers have been drawn to enhance the non linearities for telecom applications such as signal regeneration and generation of supercontinuum sources. On another hand, in the 3-12 µm window, single mode fibers and exposed core fibers have been realized for Gaussian beams propagation and sensors applications respectively.

  15. Synthesis, characterization, and structure of reduced tungsten chalcogenide cluster complexes

    Energy Technology Data Exchange (ETDEWEB)

    Xiaobing, Xie

    1997-02-01

    Over the previous twenty years, ternary molybdenum chalcogenides of the general formula M{sub x}Mo{sub 6}Y{sub 8} (M = ternary metal cation; Y = chalcogenide), known as Chevrel phases, have been extensively studied. Many of these compounds have been found to have superconductivity, catalytic activity and ionic conductivity. The rich chemistry of the Chevrel phases raises considerable interest in finding the tungsten analogues of these phases. However, no such analogue has ever been synthesized, although the Chevrel phases are usually prepared directly from elements at high temperatures above 1000{degrees}C. The absence of the tungsten analogues may be caused by their thermodynamic instability at such high temperatures. Thus it might be necessary to avoid high-temperature synthetic procedures in order to establish the ternary and binary tungsten chalcogenides. A major focus of the McCarley research group has been on the preparation of M{sub 6}Y{sub 8}L{sub 6} (M = Mo, W; Y = S, Se, Te) cluster complexes as low temperature pathways to the Chevrel phases.

  16. Forced Ion Migration for Chalcogenide Phase Change Memory Device

    Science.gov (United States)

    Campbell, Kristy A (Inventor)

    2013-01-01

    Non-volatile memory devices with two stacked layers of chalcogenide materials comprising the active memory device have been investigated for their potential as phase-change memories. The devices tested included GeTe/SnTe, Ge2Se3/SnTe, and Ge2Se3/SnSe stacks. All devices exhibited resistance switching behavior. The polarity of the applied voltage with respect to the SnTe or SnSe layer was critical to the memory switching properties, due to the electric field induced movement of either Sn or Te into the Ge-chalcogenide layer. One embodiment of the invention is a device comprising a stack of chalcogenide-containing layers which exhibit phase-change switching only after a reverse polarity voltage potential is applied across the stack causing ion movement into an adjacent layer and thus "activating" the device to act as a phase-change random access memory device or a reconfigurable electronics device when the applied voltage potential is returned to the normal polarity. Another embodiment of the invention is a device that is capable of exhibiting more than two data states.

  17. Infrared Emitting and Photoconducting Colloidal Silver Chalcogenide Nanocrystal Quantum Dots from a Silylamide-Promoted Synthesis

    NARCIS (Netherlands)

    Yarema, Maksym; Pichler, Stefan; Sytnyk, Mykhailo; Seyrkammer, Robert; Lechner, Rainer T.; Fritz-Popovski, Gerhard; Jarzab, Dorota; Szendrei, Krisztina; Resel, Roland; Korovyanko, Oleksandra; Loi, Maria Antonietta; Paris, Oskar; Hesser, Guenter; Heiss, Wolfgang; Hesser, Günter

    2011-01-01

    Here, we present a hot injection synthesis of colloidal Ag chalcogenide nanocrystals (Ag(2)Se, Ag(2)Te, and Ag(2)S) that resulted in exceptionally small nanocrystal sizes in the range between 2 and 4 nm. Ag chalcogenide nanocrystals exhibit band gap energies within the near-infrared spectral region,

  18. Recent advances in optoelectronic properties and applications of two-dimensional metal chalcogenides

    Science.gov (United States)

    Congxin, Xia; Jingbo, Li

    2016-05-01

    Since two-dimensional (2D) graphene was fabricated successfully, many kinds of graphene-like 2D materials have attracted extensive attention. Among them, the studies of 2D metal chalcogenides have become the focus of intense research due to their unique physical properties and promising applications. Here, we review significant recent advances in optoelectronic properties and applications of 2D metal chalcogenides. This review highlights the recent progress of synthesis, characterization and isolation of single and few layer metal chalcogenides nanosheets. Moreover, we also focus on the recent important progress of electronic, optical properties and optoelectronic devices of 2D metal chalcogenides. Additionally, the theoretical model and understanding on the band structures, optical properties and related physical mechanism are also reviewed. Finally, we give some personal perspectives on potential research problems in the optoelectronic characteristics of 2D metal chalcogenides and related device applications.

  19. Chemical synthesis and modification of target phases of chalcogenide nanomaterials

    Science.gov (United States)

    Sines, Ian T.

    Inorganic nanoparticles have been at the forefront of materials research in recent years due to their utility in modern technological processes. Chalcogenide nanomaterials are of particular interest because of their wide range of desirable properties for semiconductors, magnetic devices, and energy industries. Primary factors that dictate the properties of the material are the elemental composition, crystal structure, stoichiometry, crystallite size, and particle morphology. One of the most common approaches to synthesize these materials is through solution mediated routes. This approach offers unique advantages in controlling the morphology and particle size that other methods lack. This dissertation describes our recent work on exploiting solution chemical routes to control the crystal structure and composition of chalcogenide nanomaterials. We will start by discussing solution chemistry routes to synthesize non-equilibrium phases of chaclogenide nanomaterials. By using low-temperature bottom-up techniques it is possible to trap kinetically stable phases that cannot be accessed using traditional high-temperature techniques. We used solution chemistry to synthesize and characterize, for the first time, wurtzite-type MnSe. Wurtzite-type MnSe is the end-member of the highly investigated ZnxMn1-xSe solid solution, a classic magnetic semiconductor system. We will then discuss PbO-type FeS, another non-equilibrium phase that is isostructural with the superconducting phase of FeSe. We synthesized phase-pure PbO-type FeS using a low-temperature solvothermal route. We will then discuss the post-synthetic modification of chalcogenides nanomaterials. By exploiting the solubility of Se and S in tri-n-octylphosphine we can selectively extract the chalcogen from preformed chalcogenide nanomaterials. This gives chemists a technique for purification and phase-targeting of particular chalcogenide phases. This method can be modified to facilitate anion exchange. When Te is

  20. The intercalation chemistry of layered iron chalcogenide superconductors

    Science.gov (United States)

    Vivanco, Hector K.; Rodriguez, Efrain E.

    2016-10-01

    The iron chalcogenides FeSe and FeS are superconductors composed of two-dimensional sheets held together by van der Waals interactions, which makes them prime candidates for the intercalation of various guest species. We review the intercalation chemistry of FeSe and FeS superconductors and discuss their synthesis, structure, and physical properties. Before we review the latest work in this area, we provide a brief background on the intercalation chemistry of other inorganic materials that exhibit enhanced superconducting properties upon intercalation, which include the transition metal dichalcogenides, fullerenes, and layered cobalt oxides. From past studies of these intercalated superconductors, we discuss the role of the intercalates in terms of charge doping, structural distortions, and Fermi surface reconstruction. We also briefly review the physical and chemical properties of the host materials-mackinawite-type FeS and β-FeSe. The three types of intercalates for the iron chalcogenides can be placed in three categories: 1.) alkali and alkaline earth cations intercalated through the liquid ammonia technique; 2.) cations intercalated with organic amines such as ethylenediamine; and 3.) layered hydroxides intercalated during hydrothermal conditions. A recurring theme in these studies is the role of the intercalated guest in electron doping the chalcogenide host and in enhancing the two-dimensionality of the electronic structure by spacing the FeSe layers apart. We end this review discussing possible new avenues in the intercalation chemistry of transition metal monochalcogenides, and the promise of these materials as a unique set of new inorganic two-dimensional systems.

  1. Chalcogenide photovoltaics physics, technologies, and thin film devices

    CERN Document Server

    Scheer, Roland

    2011-01-01

    This first comprehensive description of the most important material properties and device aspects closes the gap between general books on solar cells and journal articles on chalcogenide-based photovoltaics. Written by two very renowned authors with years of practical experience in the field, the book covers II-VI and I-III-VI2 materials as well as energy conversion at heterojunctions. It also discusses the latest semiconductor heterojunction models and presents modern analysis concepts. Thin film technology is explained with an emphasis on current and future techniques for mass production, a

  2. 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.

  3. Ultrafast laser fabrication of Bragg waveguides in chalcogenide glass.

    Science.gov (United States)

    McMillen, Ben; Li, Mingshan; Huang, Sheng; Zhang, Botao; Chen, Kevin P

    2014-06-15

    Bragg waveguides are fundamental components in photonic integrated circuits and are particularly interesting for mid-IR applications in high index, highly nonlinear materials. In this work, we present Bragg waveguides fabricated in bulk chalcogenide glass using an ultrafast laser. Waveguides with near circularly symmetric cross sections and low propagation loss are obtained through spatial and temporal beam shaping. Using a single-pass technique, the waveguide and Bragg structure are formed at the same time. First through sixth order gratings with strengths of up to 25 dB are realized, and performance is evaluated based on the modulation duty cycle of the writing beam.

  4. Positronics of radiation-induced effects in chalcogenide glassy semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Scientific Research Company “Carat” (Ukraine); Kozyukhin, S. A., E-mail: sergkoz@igic.ras.ru [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Shpotyuk, M. [Scientific Research Company “Carat” (Ukraine); Ingram, A. [Opole Technical University (Poland); Szatanik, R. [Opole University (Poland)

    2015-03-15

    Using As{sub 2}S{sub 3} and AsS{sub 2} glasses as an example, the principal possibility of using positron annihilation spectroscopy methods for studying the evolution of the free volume of hollow nanoobjects in chalcogenide glassy semiconductors exposed to radiation is shown. The results obtained by measurements of the positron annihilation lifetime and Doppler broadening of the annihilation line in reverse chronological order are in full agreement with the optical spectroscopy data in the region of the fundamental absorption edge, being adequately described within coordination defect-formation and physical-aging models.

  5. Reversibility windows in selenide-based chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine); Institute of Physics of Jan Dlugosz University, 13/15, al. Armii Krajowej, Czestochowa, PL 42200 (Poland); Hyla, M. [Institute of Physics of Jan Dlugosz University, 13/15, al. Armii Krajowej, Czestochowa, PL 42200 (Poland); Boyko, V. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine); Lviv National Polytechnic University, 12, Bandera Street, Lviv, UA 79013 (Ukraine); Golovchak, R. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine)], E-mail: golovchak@novas.lviv.ua

    2008-10-01

    A simple route for the estimation of the reversibility windows in the sense of non-ageing ability is developed for chalcogenide glasses obeying '8-N' rule at the example of As-Se, Ge-Se and Ge-As-Se glass systems. The low limit of their reversibility windows is determined at the average coordination number Z=2.4 in full agreement with rigidity percolation theory, while the upper limit is shown to be related to the glass preparation conditions and samples prehistory.

  6. Narrow linewidth Brillouin laser based on chalcogenide photonic chip

    CERN Document Server

    Kabakova, Irina V; Choi, Duk-Yong; Debbarma, Sukhanta; Luther-Davies, Barry; Madden, Stephen J; Eggleton, Benjamin J

    2013-01-01

    We present the first demonstration of a narrow linewidth, waveguide-based Brillouin laser which is enabled by large Brillouin gain of a chalcogenide chip. The waveguides are equipped with vertical tapers for low loss coupling. Due to optical feedback for the Stokes wave, the lasing threshold is reduced to 360 mW, which is 5 times lower than the calculated single-pass Brillouin threshold for the same waveguide. The slope efficiency of the laser is found to be 30% and the linewidth of 100 kHz is measured using a self-heterodyne method.

  7. Optical properties of chalcogenide Ge-Te-In thin films

    Science.gov (United States)

    Zaidan, A.; Ivanova, V.; Petkov, P.

    2012-03-01

    Thin films of the chalcogenide (GeTe4)1-xInx with various compositions (x = 0, 5, 10, 15, 20 at %) were deposited under vacuum on glass substrates by thermal evaporation. The optical transmission and reflection spectra of the films at normal incidence were investigated in the spectral range from 800 to 2600 nm. Using the transmission spectra, the optical constants (refractive index (n) and extinction coefficient (k)) were calculated based on Swanepoel's method. The optical band gap (Egopt) was also estimated using Tauc's extrapolation procedure.

  8. The electronic structure of europium chalcogenides and pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Horne, M [Department of Physics, Keele University, Staffordshire ST5 5DY (United Kingdom); Strange, P [Department of Physics, Keele University, Staffordshire ST5 5DY (United Kingdom); Temmerman, W M [Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Szotek, Z [Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Svane, A [Institute of Physics and Astronomy, University of Aarhus, DK-8000, Aarhus (Denmark); Winter, H [INFP, Forschungzentrum Karlsruhe GmbH, Postfach 3640, D-76021, Karlsruhe (Germany)

    2004-07-21

    The electronic structure of some europium chalcogenides and pnictides is calculated using the ab initio self-interaction corrected local-spin-density approximation (SIC-LSD). This approach allows both a localized description of the rare earth f-electrons and an itinerant description of s-, p-, and d-electrons. Localizing different numbers of f-electrons on the rare earth atom corresponds to different nominal valencies, and the total energies can be compared, providing a first-principles description of valency. All the chalcogenides are found to be insulators in the ferromagnetic state and to have a divalent configuration. For the pnictides we find that EuN is half-metallic and the rest are normal metals. However, a valence change occurs as we go down the pnictide column of the periodic table. EuN and EuP are trivalent, EuAs is only just trivalent, and EuSb is found to be divalent. Our results suggest that these materials may find applications in spintronic and spin filtering devices.

  9. Microorganism mediated biosynthesis of metal chalcogenides; a powerful tool to transform toxic effluents into functional nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Vena, M. Paula; Jobbágy, Matías; Bilmes, Sara A., E-mail: sarabil@qi.fcen.uba.ar

    2016-09-15

    Cadmium contained in soil and water can be taken up by certain crops and aquatic organisms and accumulate in the food-chain, thus removal of Cd from mining or industrial effluents – i.e. Ni-Cd batteries, electroplating, pigments, fertilizers – becomes mandatory for human health. In parallel, there is an increased interest in the production of luminescent Q-dots for applications in bioimaging, sensors and electronic devices, even the present synthesis methods are economic and environmentally costly. An alternative green pathway for producing Metal chalcogenides (MC: CdS, CdSe, CdTe) nanocrystals is based on the metabolic activity of living organisms. Intracellular and extracellular biosynthesis of can be achieved within a biomimetic approach feeding living organisms with Cd precursors providing new routes for combining bioremediation with green routes for producing MC nanoparticles. In this mini-review we present the state-of-the-art of biosynthesis of MC nanoparticles with a critical discussion of parameters involved and protocols. Few existing examples of scaling-up are also discussed. A modular reactor based on microorganisms entrapped in biocompatible mineral matrices – already proven for bioremediation of dissolved dyes – is proposed for combining both Cd-depletion and MC nanoparticle's production. - Highlights: • Removal of heavy metals by living matter is feasible trough biosorption and bioaccumulation • Algae, fungi, bacteria and yeasts can synthesize CdS, CdSe and CdTe Q-dots • Encapsulation of microorganisms in mineral gels provides building blocks for reactor design. • Depletion of Cd with production of Q-dots can be achieved with modular bioreactors with entrapped cells.

  10. Mineral resources

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    Marine minerals have been center of attraction to mankind since ancient times. The technological advances in the recent years show that the retrieval of underwater minerals from deep-sea can no longer be a dream. Marine minerals are terrigenous...

  11. How metallic is the binding state of indium hosted by excess-metal chalcogenides in ore deposits?

    Science.gov (United States)

    Ondina Figueiredo, Maria; Pena Silva, Teresa; Oliveira, Daniel; Rosa, Diogo

    2010-05-01

    Discovered in 1863, indium is nowadays a strategic scarce metal used both in classical technologic fields (like low melting-temperature alloys and solders) and in innovative nano-technologies to produce "high-tech devices" by means of new materials, namely liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) and the recently introduced transparent flexible thin-films manufactured with ionic amorphous oxide semiconductors (IAOS). Indium is a typical chalcophile element, seldom forming specific minerals and occurring mainly dispersed within polymetallic sulphides, particularly with excess metal ions [1]. The average content of indium in the Earth's crust is very low but a further increase in its demand is still expected in the next years, thus focusing a special interest in uncovering new exploitation sites through promising polymetallic sulphide ores - e.g., the Iberian Pyrite Belt (IPB) [2] - and in improving recycling technologies. Indium recovery stands mostly on zinc extraction from sphalerite, the natural cubic sulphide which is the prototype of so-called "tetrahedral sulphides" where metal ions fill half of the available tetrahedral sites within the cubic closest packing of sulphur anions where the double of unfilled interstices are available for further in-filling. It is worth remarking that such packing array is particularly suitable for accommodating polymetallic cations by filling closely located interstitial sites [3] as happens in excess-metal tetrahedral sulphides - e.g. bornite, ideally Cu5FeS4, recognized as an In-carrying mineral [4]. Studying the tendency towards In-In interactions able of leading to the formation of polycations would efficiently contribute to understand indium crystal chemistry and the metal binding state in natural chalcogenides. Accordingly, an X-ray absorption near-edge spectroscopy (XANES) study at In L3-edge was undertaken using the instrumental set-up of ID21 beamline at the ESRF (European Synchrotron

  12. New Trends in Amplifiers and Sources via Chalcogenide Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    L. Mescia

    2012-01-01

    Full Text Available Rare-earth-doped chalcogenide glass fiber lasers and amplifiers have great applicative potential in many fields since they are key elements in the near and medium-infrared (mid-IR wavelength range. In this paper, a review, even if not exhaustive, on amplification and lasing obtained by employing rare-earth-doped chalcogenide photonic crystal fibers is reported. Materials, devices, and feasible applications in the mid-IR are briefly mentioned.

  13. Gadolinium-Induced Multi-Effect on Properties of IR Transmitting Chalcogenide Glasses

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dong-Hui; XIA Fang; NIE Jia-Xiang; CHEN Guo-Rong; ZHANG Xiang-Hua; MA Hong-Li; ADAM Jean-Luc

    2004-01-01

    @@ We introduce gadolinium in chalcogenide glasses to exert unexpectedly the multiple magical effects on both optical and thermal mechanical properties of chalcogenide glasses. Notable increases in transition temperature Tg and microhardness Hv were observed due to structural densitication and microcrystallization. Calculated molar volume values, differential scanning calorimetry and x-ray diffraction measurements provide supporting evidences. Gadolinium also acts as oxygen getter by removing or weakening oxygen-related absorption bands,which is associated with the higher negative electrode potential.

  14. Visible-active photocatalytic behaviors observed in nanostructured lead chalcogenides PbX (X = S, Se, Te)

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Li-Na; Wang, H.C.; Shen, Y.; Lin, Yuan-Hua, E-mail: linyh@mail.tsinghua.edu.cn; Nan, Ce-Wen [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2016-01-15

    Nanostructured lead chalcogenides (PbX, X = Te, Se, S) were prepared via a simple hydrothermal method. The powder samples were characterized by XRD, SEM, SAED and DRS. Phase composition and microstructure analysis indicate that these samples are pure lead chalcogenides phases and have similar morphologies. These lead chalcogenides display efficient absorption in the UV-visible light range. The photocatalytic properties of lead chalcogenides nanoparticles were evaluated by the photodegradation of Congo red under UV-visible light irradiation in air atmosphere. The Congo red solution can be efficiently degraded under visible light in the presence of lead chalcogenides nanoparticles. The photocatalytic activities of lead chalcogenides generally increase with increasing their band gaps and shows no appreciable loss after repeated cycles. Our results may be useful for developing new photocatalyst systems responsive to visible light among narrow band gap semiconductors.

  15. Visible-active photocatalytic behaviors observed in nanostructured lead chalcogenides PbX (X = S, Se, Te

    Directory of Open Access Journals (Sweden)

    Li-Na Qiao

    2016-01-01

    Full Text Available Nanostructured lead chalcogenides (PbX, X = Te, Se, S were prepared via a simple hydrothermal method. The powder samples were characterized by XRD, SEM, SAED and DRS. Phase composition and microstructure analysis indicate that these samples are pure lead chalcogenides phases and have similar morphologies. These lead chalcogenides display efficient absorption in the UV-visible light range. The photocatalytic properties of lead chalcogenides nanoparticles were evaluated by the photodegradation of Congo red under UV-visible light irradiation in air atmosphere. The Congo red solution can be efficiently degraded under visible light in the presence of lead chalcogenides nanoparticles. The photocatalytic activities of lead chalcogenides generally increase with increasing their band gaps and shows no appreciable loss after repeated cycles. Our results may be useful for developing new photocatalyst systems responsive to visible light among narrow band gap semiconductors.

  16. Comparison of loss in silica and chalcogenide negative curvature fibers as the wavelength varies

    Directory of Open Access Journals (Sweden)

    Chengli Wei

    2016-07-01

    Full Text Available We computationally study fiber loss in negative curvature fibers made with silica, As2S3 chalcogenide, and As2Se3 chalcogenide glasses with a fixed core-diameter-to-wavelength ratio of 30. We consider both simple and nested geometries as the transmission wavelength varies. At wavelengths shorter than 4.5 µm, silica negative curvature fibers have a loss that is around or below 0.1 dB/m and are preferable to chalcogenide fibers. At wavelengths longer than 4.5 µm, it is preferable to use As2S3 chalcogenide or As2Se3 chalcogenide negative curvature fibers since their loss is one or more orders of magnitude lower than the loss of silica negative curvature fibers. With nested negative curvature fibers, chalcogenide fibers have losses that are lower than those of silica fibers at wavelengths larger than 2 µm. However, it is still preferable to use silica nested negative curvature fibers at wavelengths less than 4.5 µm and with a loss around or lower than 0.1 dB/m due to the fabrication advantages of silica fibers.

  17. Analysis of switching conditions of chalcogenide alloys during crystallization

    Institute of Scientific and Technical Information of China (English)

    Wanhua Yu; C.D. Wright

    2006-01-01

    To understand the principle and limitation of chalcogenide alloy Ge2Sb2Te5 (GST) in solid-state memory devices during crystallization, it was necessary to develop a physically realistic model that could reflect the electrical and thermal properties of these media. A novel comprehensive numerical model has been developed for simulating these memory devices, which describes the electrical and thermal behavior using the solution of the nonlinear, time-dependent electrical and heat conduction equation. The finite-difference-time-domain technique was adopted to compute the electrical field and heat distribution in the device. Several contributing factors that affect the crystallization switching process such as the geometry of the GST layer, temperature and electric field dependency of the electrical conductivity have been discussed. The results of the simulations were then used to provide critical guidelines for fabrication and optimization of the device performance.

  18. Electrical conduction mechanism in GeSeSb chalcogenide glasses

    Indian Academy of Sciences (India)

    Vandana Kumari; Anusaiya Kaswan; D Patidar; Kananbala Sharma; N S Saxena

    2016-02-01

    Electrical conductivity of chalcogenide glassy system Ge$_{30−x}$Se$_{70}$Sb$_{x}$ ( = 10, 15, 20 and 25) prepared by melt quenching has been determined at different temperatures in bulk through the $I$–$V$ characteristic curves. It is quite evident from results that Poole–Frenkel conduction mechanisms hold good for conduction in these glasses in a given temperature range. The variation in electrical conductivity with composition was attributed to the Se–Sb bond concentration in the Se–Ge–Sb system. Results indicated that Ge$_5$Se$_{70}$Sb$_{25}$ showed the minimum resistance. In view of this the composition Ge$_5$Se$_{70}$Sb$_{25}$ may be coined as ‘critical composition’ in the proposed series. Also the activation energies of conduction of these glassy alloys have been calculated in higher and lower temperature range using the Arrhenius equation.

  19. Phase segregation in Pb:GeSbTe chalcogenide system

    Science.gov (United States)

    Kumar, J.; Ahmad, M.; Chander, R.; Thangaraj, R.; Sathiaraj, T. S.

    2008-01-01

    Effect of Pb substitution on the amorphous-crystalline transformation temperature, optical band gap and crystalline structure of Ge{2}Sb{2}Te{5} has been studied. In Pb:GeSbTe chalcogenide films prepared by thermal evaporation, an amorphous to crystallization transition is observed at 124, 129, 136 and 138 °C in Pb{0}Ge{20}Sb{24}Te{56}, Pb{1.6}Ge{19}Sb{26}Te{54}, Pb{3}Ge{17}Sb{28}Te{53} and Pb{5}Ge{12}Sb{28}Te{55} respectively. XRD investigations of annealed samples reveal that Pb substitution retains NaCl type crystalline structure of GST but expands the lattice due to large atomic radii. The increase in amorphous-crystalline transformation temperature is followed with the increase in phase segregation. The optical gap shows marginal variations with composition.

  20. Phase transformation in Pb:GeSbTe chalcogenide films

    Science.gov (United States)

    Kumar, J.; Kumar, P.; Ahmad, M.; Chander, R.; Thangaraj, R.; Sathiaraj, T. S.

    2008-11-01

    A comprehensive analysis on the amorphous to crystalline phase transformation in Pb:GeSbTe chalcogenide alloy has been discussed. The structure identified with X-ray measurements has been discussed in relation to thermal analysis carried out on bulk samples. Optical constants have been calculated in the 350 to 800 nm wavelength range, using Fresnel's equation. The effect of Pb substitution on the optical contrast in terms of change in reflectivity and optical parameters (viz. refractive index, extinction coefficient) has been discussed. Marginal decrease in the optical contrast has been observed with a small increase in Pb content, which is effective to maintain the sufficient signal to noise ratio for optical phase-change storage.

  1. Longitudinal Magnetoresistance and "Chiral" Coupling in Silver Chalcogenides

    Institute of Scientific and Technical Information of China (English)

    XU Jie; ZHANG Duan-Ming

    2011-01-01

    A complex longitudinal magnetoresistance (MR∥) effect in the non-stoichiometric silver chalcogenides (include the silver selenide and telluride) has been found, however the mechanism for the MR∥ effect is not clear now.In this work, a new random resistor network for MR∥ effect is proposed based on the experimental observation. The network is constructed from six-terminal resistor units and the mobility of carries within the network has a Gaussian distribution. Considering the non-zero transverse-longitudinal coupling in materials, the resistance matrix of the sixterminal resistor unit is modified. It is found that the material has the "chiral" transverse-longitudinal couplings, which is suggested a main reason for the complex MR∥ effect. The model predictions are compared with the experimental results.A three dimension (3D) visualization of current flow within the network demonstrates the "current jets" phenomenon in the thickness of materials clearly.

  2. Flexible chalcogenide glass microring resonator for mid-infrared emission

    Science.gov (United States)

    Wang, Liangliang; Li, Lijing; Sun, Mingjie

    2016-10-01

    Emerging applications in communication, sensing, medical, and many other fields call for on-chip microring laser, however, the method to make it work at mid-infrared still need to be explored. In this paper, a microring resonator integrated in flexible substrate is designed and evaluated, with high Q-factor ( 105) at pump and signal wavelengths, achieving emission in mid-infrared (3.6μm) using rare earth doped chalcogenide glass. Furthermore, the strain-optical coupling in multilayer flexible materials is numerically verified, and a 0.3 nm/μɛ resonance wavelength shift is achieved by local neutral axis theory, without significant loss of flexible device performance.

  3. Meyer–Neldel DC conduction in chalcogenide glasses

    Indian Academy of Sciences (India)

    S PraKash; Kulbir Kaur; Navdeep Goyal; S K Tripathi

    2011-04-01

    Meyer–Neldel (MN) formula for DC conductivity (DC) of chalcogenide glasses is obtained using extended pair model and random free energy barriers. The integral equations for DC hopping conductivity and external conductance are solved by iterative procedure. It is found that MN energy ( MN) originates from temperature-induced configurational and electronic disorders. Single polaron-correlated barrier hopping model is used to calculate DC and the experimental data of Se, As2S3, As2Se3 and As2Te3 are explained. The variation of attempt frequency 0 and MN with parameter (/), where is the intersite separation and is the radius of localized states, is also studied. It is found that 0 and MN decrease with increase of (/), and MN may not be present for low density of defects.

  4. Fabrication and characterization of chalcogenide glass photonic crystal waveguides.

    Science.gov (United States)

    Suzuki, Keijiro; Hamachi, Yohei; Baba, Toshihiko

    2009-12-07

    We report on the fabrication of chalcogenide glass (Ag-As(2)Se(3)) photonic crystal waveguides and the first detailed characterization of the linear and nonlinear optical properties. The waveguides, fabricated by e-beam lithography and ICP etching exhibit typical transmission spectra of photonic crystal waveguides, and exhibit high optical nonlinearity. Nonlinear phase shift of 1.5pi through self-phase modulation is observed at 0.78 W input peak power in a 400 microm long device. The effective nonlinear parameter gamma(eff) estimated from this result reaches 2.6 x 10(4) W(-1)m(-1). Four-wave mixing is also observed in the waveguide, while two-photon absorption at optical communication wavelengths is sufficiently small and the corresponding figure of merit is larger than 11.

  5. Chalcogenide Glass Radiation Sensor; Materials Development, Design and Device Testing

    Energy Technology Data Exchange (ETDEWEB)

    Mitkova, Maria; Butt, Darryl; Kozicki, Michael; Barnaby, Hugo

    2013-04-30

    For many decades, various radiation detecting material have been extensively researched, to find a better material or mechanism for radiation sensing. Recently, there is a growing need for a smaller and effective material or device that can perform similar functions of bulkier Geiger counters and other measurement options, which fail the requirement for easy, cheap and accurate radiation dose measurement. Here arises the use of thin film chalcogenide glass, which has unique properties of high thermal stability along with high sensitivity towards short wavelength radiation. The unique properties of chalcogenide glasses are attributed to the lone pair p-shell electrons, which provide some distinctive optical properties when compared to crystalline material. These qualities are derived from the energy band diagram and the presence of localized states in the band gap. Chalcogenide glasses have band tail states and localized states, along with the two band states. These extra states are primarily due to the lone pair electrons as well as the amorphous structure of the glasses. The localized states between the conductance band (CB) and valence band (VB) are primarily due to the presence of the lone pair electrons, while the band tail states are attributed to the Van der Waal's forces between layers of atoms [1]. Localized states are trap locations within the band gap where electrons from the valence band can hop into, in their path towards the conduction band. Tail states on the other hand are locations near the band gap edges and are known as Urbach tail states (Eu). These states are occupied with many electrons that can participate in the various transformations due to interaction with photons. According to Y. Utsugi et. al.[2], the electron-phonon interactions are responsible for the generation of the Urbach tails. These states are responsible for setting the absorption edge for these glasses and photons with energy near the band gap affect these states. We have

  6. Qualification and metrology for US-produced chalcogenides

    Science.gov (United States)

    Carlie, Nathan

    2012-06-01

    The recent trend in infrared optics has been toward higher resolution with wider fields of view, lower weight and size, and broader temperature ranges. This places much more stringent requirements on the measurement and control of the properties of the optical materials within these systems. In response to these demands, SCHOTT North America recently announced domestic production of the IG glass series (IG2-IG6) of chalcogenide glasses within the US which has spurred renewed focus the characterization to bring these glasses to a similar level as standard optical glasses. This paper will present and discuss the novel inspection systems and the process used to qualify refractive index of these materials, with a focus on data presentation, in order to demonstrate the methodology and utility of the methods and data produced.

  7. 10 um wavefront spatial filtering first results with chalcogenide fibers

    CERN Document Server

    Bordé, P J; Nguyen, T; Amy-Klein, A; Daussy, C; Raynal, P; Léger, A; Mazé, G; Borde, Pascal; Perrin, Guy; Nguyen, Thanh; Amy-Klein, Anne; Daussy, Christophe; Raynal, Pierre-Ivan; Leger, Alain; Maze, Gwenael

    2003-01-01

    Wavefront cleaning by single-mode fibers has proved to be efficient in optical-infrared interferometry to improve calibration quality. For instance, the FLUOR instrument has demonstrated the capability of fluoride glass single-mode fibers in this respect in the K and L bands. New interferometric instruments developped for the mid-infrared require the same capability for the 8-12 um range. We have initiated a program to develop single-mode fibers in the prospect of the VLTI mid-infrared instrument MIDI and of the ESA/DARWIN and NASA/TPF missions that require excellent wavefront quality. In order to characterize the performances of chalcogenide fibers we are developping, we have set up an experiment to measure the far-field pattern radiated at 10 um. In this paper, we report the first and promising results obtained with this new component.

  8. Structural phase transition and elastic properties of mercury chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, Dinesh, E-mail: vdinesh33@rediffmail.com [School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001 (India); Shriya, S. [School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001 (India); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Departement de Technologie, Universite de Mascara, 29000 Mascara (Algeria)

    2012-08-15

    Pressure induced structural transition and elastic properties of ZnS-type (B3) to NaCl-type (B1) structure in mercury chalcogenides (HgX; X = S, Se and Te) are presented. An effective interionic interaction potential (EIOP) with long-range Coulomb, as well charge transfer interactions, Hafemeister and Flygare type short-range overlap repulsion extended up to the second neighbor ions and van der Waals interactions are considered. Emphasis is on the evaluation of the pressure dependent Poisson's ratio {nu}, the ratio R{sub BT/G} of B (bulk modulus) over G (shear modulus), anisotropy parameter, Shear and Young's modulus, Lame constant, Kleinman parameter, elastic wave velocity and thermodynamical property as Debye temperature. The Poisson's ratio behavior infers that Mercury chalcogenides are brittle in nature. To our knowledge this is the first quantitative theoretical prediction of the pressure dependence of elastic and thermodynamical properties explicitly the ductile (brittle) nature of HgX and still awaits experimental confirmations. Highlights: Black-Right-Pointing-Pointer Vast volume discontinuity in phase diagram infers transition from ZnS to NaCl structure. Black-Right-Pointing-Pointer The shear elastic constant C{sub 44} is nonzero confirms the mechanical stability. Black-Right-Pointing-Pointer Pressure dependence of {theta}{sub D} infers the softening of lattice with increasing pressure. Black-Right-Pointing-Pointer Estimated bulk, shear and tetragonal moduli satisfied elastic stability criteria. Black-Right-Pointing-Pointer In both B3 and B1 phases, C{sub 11} and C{sub 12} increase linearly with pressure.

  9. Mineral oils

    Science.gov (United States)

    Furby, N. W.

    1973-01-01

    The characteristics of lubricants made from mineral oils are discussed. Types and compositions of base stocks are reviewed and the product demands and compositions of typical products are outlined. Processes for commercial production of mineral oils are examined. Tables of data are included to show examples of product types and requirements. A chemical analysis of three types of mineral oils is reported.

  10. Infrared emitting and photoconducting colloidal silver chalcogenide nanocrystal quantum dots from a silylamide-promoted synthesis.

    Science.gov (United States)

    Yarema, Maksym; Pichler, Stefan; Sytnyk, Mykhailo; Seyrkammer, Robert; Lechner, Rainer T; Fritz-Popovski, Gerhard; Jarzab, Dorota; Szendrei, Krisztina; Resel, Roland; Korovyanko, Oleksandra; Loi, Maria Antonietta; Paris, Oskar; Hesser, Günter; Heiss, Wolfgang

    2011-05-24

    Here, we present a hot injection synthesis of colloidal Ag chalcogenide nanocrystals (Ag(2)Se, Ag(2)Te, and Ag(2)S) that resulted in exceptionally small nanocrystal sizes in the range between 2 and 4 nm. Ag chalcogenide nanocrystals exhibit band gap energies within the near-infrared spectral region, making these materials promising as environmentally benign alternatives to established infrared active nanocrystals containing toxic metals such as Hg, Cd, and Pb. We present Ag(2)Se nanocrystals in detail, giving size-tunable luminescence with quantum yields above 1.7%. The luminescence, with a decay time on the order of 130 ns, was shown to improve due to the growth of a monolayer thick ZnSe shell. Photoconductivity with a quantum efficiency of 27% was achieved by blending the Ag(2)Se nanocrystals with a soluble fullerene derivative. The co-injection of lithium silylamide was found to be crucial to the synthesis of Ag chalcogenide nanocrystals, which drastically increased their nucleation rate even at relatively low growth temperatures. Because the same observation was made for the nucleation of Cd chalcogenide nanocrystals, we conclude that the addition of lithium silylamide might generally promote wet-chemical synthesis of metal chalcogenide nanocrystals, including in as-yet unexplored materials.

  11. Alloyed copper chalcogenide nanoplatelets via partial cation exchange reactions.

    Science.gov (United States)

    Lesnyak, Vladimir; George, Chandramohan; Genovese, Alessandro; Prato, Mirko; Casu, Alberto; Ayyappan, S; Scarpellini, Alice; Manna, Liberato

    2014-08-26

    We report the synthesis of alloyed quaternary and quinary nanocrystals based on copper chalcogenides, namely, copper zinc selenide-sulfide (CZSeS), copper tin selenide-sulfide (CTSeS), and copper zinc tin selenide-sulfide (CZTSeS) nanoplatelets (NPLs) (∼20 nm wide) with tunable chemical composition. Our synthesis scheme consisted of two facile steps: i.e., the preparation of copper selenide-sulfide (Cu2-xSeyS1-y) platelet shaped nanocrystals via the colloidal route, followed by an in situ cation exchange reaction. During the latter step, the cation exchange proceeded through a partial replacement of copper ions by zinc or/and tin cations, yielding homogeneously alloyed nanocrystals with platelet shape. Overall, the chemical composition of the alloyed nanocrystals can easily be controlled by the amount of precursors that contain cations of interest (e.g., Zn, Sn) to be incorporated/alloyed. We have also optimized the reaction conditions that allow a complete preservation of the size, morphology, and crystal structure as that of the starting Cu2-xSeyS1-y NPLs. The alloyed NPLs were characterized by optical spectroscopy (UV-vis-NIR) and cyclic voltammetry (CV), which demonstrated tunability of their light absorption characteristics as well as their electrochemical band gaps.

  12. Nonlinear characterization of GeSbS chalcogenide glass waveguides

    Science.gov (United States)

    Choi, Ju Won; Han, Zhaohong; Sohn, Byoung-Uk; Chen, George F. R.; Smith, Charmayne; Kimerling, Lionel C.; Richardson, Kathleen A.; Agarwal, Anuradha M.; Tan, Dawn T. H.

    2016-12-01

    GeSbS ridge waveguides have recently been demonstrated as a promising mid – infrared platform for integrated waveguide – based chemical sensing and photodetection. To date, their nonlinear optical properties remain relatively unexplored. In this paper, we characterize the nonlinear optical properties of GeSbS glasses, and show negligible nonlinear losses at 1.55 μm. Using self – phase modulation experiments, we characterize a waveguide nonlinear parameter of 7 W‑1/m and nonlinear refractive index of 3.71 × 10‑18 m2/W. GeSbS waveguides are used to generate supercontinuum from 1280 nm to 2120 nm at the ‑30 dB level. The spectrum expands along the red shifted side of the spectrum faster than on the blue shifted side, facilitated by cascaded stimulated Raman scattering arising from the large Raman gain of chalcogenides. Fourier transform infrared spectroscopic measurements show that these glasses are optically transparent up to 25 μm, making them useful for short – wave to long – wave infrared applications in both linear and nonlinear optics.

  13. Generation of λ/12 nanowires in chalcogenide glasses.

    Science.gov (United States)

    Nicoletti, Elisa; Bulla, Douglas; Luther-Davies, Barry; Gu, Min

    2011-10-12

    Nanowires have been widely studied and have gained a lot of interest in the past decade. Because of their high refractive index and high nonlinearity, chalcogenide glasses (ChGs) are a good candidate for the fabrication of photonic nanowires as such nanowaveguides provide the maximal confinement of light, enabling large enhancement of nonlinear interactions and group-velocity dispersion engineering. Here we report on the generation of λ/12 (∼68 nm) nanowires based on the theoretical and experimental study of the influence of the laser repetition rate on the direct laser fabrication in ChGs (λ = 800 nm). Through a numerical model of cumulative heating, the optimum conditions for high-resolution fabrication in As(2)S(3) are found. Nanowires with dimensions down to ∼λ/12 are for the first time successfully fabricated in ChGs. We show that the generated nanowires can be stacked to form a three-dimensional woodpile photonic crystal with a pronounced stop gap.

  14. Palladium and platinum organochalcogenolates and their transformation into metal chalcogenides

    Indian Academy of Sciences (India)

    S Dey; S Narayan; A Singhal; V K Jain

    2000-06-01

    Platinum group metal chalcogenides find extensive applications in catalysis and in the electronic industry. To develop an efficient low temperature clean preparation of these materials, molecular routes have been explored. Thus the chemistry of mononuclear organochalcogenolates of the type [M(ER 1/4)2(PR3)2], binuclear benzylselenolates, [M2Cl2(∼-SeBz)2(PR3)2], allylpalladium complexes [Pd2(μ-ER)2(3-C4H7)2] and palladium/platinum sulphido/selenido-bridged complexes, [M2(μ-E)2L4] (M = Pd or Pt; E = S, Se or Te; L = tertiary phosphine ligand) has been investigated. All the complexes have been characterized by elemental analysis, NMR (1 H, 31P, 77Se, 195Pt) spectroscopy and in some cases by X-ray diffraction. The thermal behaviour of these complexes has been studied by TGA. The pyrolysis of allylpalladium complexes in refluxing xylene yields Pd4E as established by analysis and XRD patterns.

  15. Raman spectroscopy of chalcogenide thin films prepared by PLD

    Energy Technology Data Exchange (ETDEWEB)

    Erazu, M.; Rocca, J. [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires - CONICET, Paseo Colon 850, 1063 Buenos Aires (Argentina); Fontana, M., E-mail: merazu@fi.uba.a [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires - CONICET, Paseo Colon 850, 1063 Buenos Aires (Argentina); Urena, A.; Arcondo, B. [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires - CONICET, Paseo Colon 850, 1063 Buenos Aires (Argentina); Pradel, A. [ICG, UMR 5253 CNRS UM 2 ENSCM UM1 equipe PMDP CC3, Universite Montpellier 2, 34095 Montpellier Cedex 5 (France)

    2010-04-16

    Chalcogenide glasses have many technological applications as a result of their particular optical and electrical properties. Ge-Se and Ag-Ge-Se systems were recently studied and tested as new materials for building non-volatile memories. Following these ideas, thin films of Ge-Se and Ag-Ge-Se were deposited using pulsed laser deposition (PLD). Ag was sputtered over binary films (for a composition between 0.05 and 0.25 Ag atomic fraction) and photo-diffused afterwards. Thus, three kinds of samples were analyzed by means of Raman spectroscopy, in order to provide information on the short- and medium-range order: PLD binary films before Ag doping, after Ag doping and PLD ternary films. Before Ag doping, binary films exhibited Ge-Se corner-sharing tetrahedra modes at 190 cm{sup -1}, low scattering from edge-sharing tetrahedra at 210 cm{sup -1}, and Se chains at 260 cm{sup -1} (stretching mode). However, after the diffusion process was complete, we observed an intensity reduction of bands centered at 210 cm{sup -1} and 260 cm{sup -1}. The spectra of the photo-diffused films were similar to those of films deposited using a ternary target. Relaxation effects in binary glasses were also analyzed. Results were compared with those of other authors.

  16. Low threshold fiber taper coupled rare earth ion-doped chalcogenide microsphere laser

    Institute of Scientific and Technical Information of China (English)

    李超然; 戴世勋; 张勤远; 沈祥; 王训四; 张培晴; 路来伟; 吴越豪; 吕社钦

    2015-01-01

    We report the applications of a low-cost and environmentally friendly chalcogenide glass, 75GeS2-15Ga2S3-10CsI, in building active microsphere laser oscillators. A silica fiber taper is used as the coupling mechanism. With an 808-nm laser diode as a pump source, we show that a high-Q (∼6×104) laser mode could be obtained from a 75-µm diameter microsphere that is coupled with a 1.77-µm waist-diameter fiber taper. The threshold of the incident pump power is 1.39 mW, which is considerably lower than those of previously reported free-space coupled chalcogenide microsphere lasers. We also note an apparent enhancement in laser power generated from this chalcogenide microsphere laser.

  17. Theoretical studies on mid-infrared amplification in Ho{sup 3+}-doped chalcogenide glass fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Shulin [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); College of Information Science and Engineering, Ningbo University, Ningbo 315211 (China); Xu, Yinsheng [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); The School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Dai, Shixun, E-mail: daishixun@nbu.edu.cn [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); College of Information Science and Engineering, Ningbo University, Ningbo 315211 (China); Zhou, Yaxun [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); College of Information Science and Engineering, Ningbo University, Ningbo 315211 (China); Lin, Changgui [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); The School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Zhang, Peiqing [Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211 (China); College of Information Science and Engineering, Ningbo University, Ningbo 315211 (China)

    2013-05-01

    This paper investigated the MIR emission of Ho{sup 3+}-doped Ge{sub 20}Ga{sub 5}Sb{sub 10}S{sub 65} chalcogenide glasses upon excitation of 900 nm laser diode. The spontaneous emission probability, absorption cross-section, and emission cross-section were calculated using the Judd-Ofelt theory and the Fuchbauer–Ladenburg equation. Theoretical studies of the Ho{sup 3+}-doped chalcogenide glass fiber amplifier operating in the MIR wavelength range, specifically around the 2.86 μm wavelength, were performed based on the rate and light propagation equations. The results indicate that the chalcogenide glass fiber presented a larger signal MIR gain and wider MIR gain spectrum. The maximum signal gain was 36 dB and the gain width was 20 dB.

  18. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Novak, Spencer; Richardson, Kathleen [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Materials Science and Engineering, COMSET, Clemson University, Clemson, South Carolina 29634 (United States); Fathpour, Sasan, E-mail: fathpour@creol.ucf.edu [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States)

    2015-03-16

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes.

  19. Destructive Clustering of Metal Nanoparticles in Chalcogenide and Oxide Glassy Matrices.

    Science.gov (United States)

    Shpotyuk, M V; Shpotyuk, O I; Cebulski, J; Kozyukhin, S

    2016-12-01

    The energetic χ-criterion is developed to parameterize difference in the origin of high-order optical non-linearity associated with metallic atoms (Cu, Ag, Au) embedded destructively in oxide- and chalcogenide glasses. Within this approach, it is unambiguously proved that covalent-bonded networks of soft semiconductor chalcogenides exemplified by binary As(Ge)-S(Se) glasses differ essentially from those typical for hard dielectric oxides like vitreous silica by impossibility to accommodate pure agglomerates of metallic nanoparticles. In an excellence according to known experimental data, it is suggested that destructive clustering of nanoparticles is possible in Cu-, Ag-, and Au-ion-implanted dielectric oxide glass media, possessing a strongly negative χ-criterion. Some recent speculations trying to ascribe equally this ability to soft chalcogenide glasses despite an obvious difference in the corresponding bond dissociation energies have been disclosed and criticized as inconclusive.

  20. Precision glass molding of complex shaped chalcogenide glass lenses for IR applications

    Science.gov (United States)

    Staasmeyer, Jan-Helge; Wang, Yang; Liu, Gang; Dambon, Olaf; Klocke, Fritz

    2016-09-01

    The use of chalcogenide glass in the thermal infrared domain is an emerging alternative to commonly used crystalline materials such as germanium. The main advantage of chalcogenide glass is the possibility of mass production of complex shaped geometries with replicative processes such as precision glass molding. Thus costly single point diamond turning processes are shifted to mold manufacturing and do not have to be applied to every single lens produced. The usage of FEM-Simulation is mandatory for developing a molding process for complex e.g. non rotational symmetric chalcogenide glass lenses in order to predict the flow of glass. This talk will present state of the art modelling of the precision glass molding process for chalcogenide glass lenses, based on thermal- and mechanical models. Input data for modelling are a set of material properties of the specific chalcogenide glass in conjunction with properties of mold material and wear protective coatings. Specific properties for the mold-glass interaction such as stress relaxation or friction at the glassmold interface cannot be obtained from datasheets and must be determined experimentally. A qualified model is a powerful tool to optimize mold and preform designs in advance in order to achieve sufficient mold filling and compensate for glass shrinkage. Application of these models in an FEM-Simulation "case study" for molding a complex shaped non-rotational symmetric lens is shown. The outlook will examine relevant issues for modelling the precision glass molding process of chalcogenide glasses in order to realize scaled up production in terms of multi cavity- and wafer level molding.

  1. Rings, chains and planes: Variation of g with composition in chalcogenide glasses

    Indian Academy of Sciences (India)

    P K Thiruvikraman

    2006-08-01

    We propose a microscopic, phenomenological model for the decrease in the viscosity observed at glass transition. Our model is primarily applicable to chalcogenide glasses. According to this model, the decrease in the viscosity at glass transition is mainly due to the breaking of the Van der Waals bonds in the chalcogenides. Using this model, we derive a relationship between the glass transition temperature, g, and the molar volume m. The validity of this relation is checked using experimental data available in the literature for two binary systems (Ge–Se and As–S) and a pseudo-binary system (As40SeTe60–).

  2. An overview of the Fe-chalcogenide superconductors

    Science.gov (United States)

    Wu, M. K.; Wu, P. M.; Wen, Y. C.; Wang, M. J.; Lin, P. H.; Lee, W. C.; Chen, T. K.; Chang, C. C.

    2015-08-01

    This review intends to summarize recent advancements in FeSe and related systems. The FeSe and related superconductors are currently receiving considerable attention for the high critical temperature (T C) observed and for many similar features to the high T C cuprate superconductors. These similarities suggest that understanding the FeSe-based compounds could potentially help our understanding of the cuprates. We begin the review by presenting common features observed in the FeSe- and FeAs-based systems. Then we discuss the importance of careful control of the material preparation allowing for a systematic structure characterization. With this control, numerous rich phases have been observed. Importantly, we suggest that the Fe-vacancy ordered phases found in the FeSe-based compounds, which are non-superconducting magnetic Mott insulators, are the parent compounds of the superconductors. Superconductivity can emerge from the parent phases by disordering the Fe vacancy order, often by a simple annealing treatment. Then we review physical properties of the Fe chalcogenides, specifically the optical properties and angle-resolved photoemission spectroscopy (ARPES) results. From the literature, strong evidence points to the existence of orbital modification accompanied by a gap-opening, prior to the structural phase transition, which is closely related to the occurrence of superconductivity. Furthermore, strong lattice to spin coupling are important for the occurrence of superconductivity in FeSe. Therefore, it is believed that the iron selenides and related compounds will provide essential information to understand the origin of superconductivity in the iron-based superconductors, and possibly the superconducting cuprates.

  3. Static Behavior of Chalcogenide Based Programmable Metallization Cells

    Science.gov (United States)

    Rajabi, Saba

    Nonvolatile memory (NVM) technologies have been an integral part of electronic systems for the past 30 years. The ideal non-volatile memory have minimal physical size, energy usage, and cost while having maximal speed, capacity, retention time, and radiation hardness. A promising candidate for next-generation memory is ion-conducting bridging RAM which is referred to as programmable metallization cell (PMC), conductive bridge RAM (CBRAM), or electrochemical metallization memory (ECM), which is likely to surpass flash memory in all the ideal memory characteristics. A comprehensive physics-based model is needed to completely understand PMC operation and assist in design optimization. To advance the PMC modeling effort, this thesis presents a precise physical model parameterizing materials associated with both ion-rich and ion-poor layers of the PMC's solid electrolyte, so that captures the static electrical behavior of the PMC in both its low-resistance on-state (LRS) and high resistance off-state (HRS). The experimental data is measured from a chalcogenide glass PMC designed and manufactured at ASU. The static on- and off-state resistance of a PMC device composed of a layered (Ag-rich/Ag-poor) Ge30Se70 ChG film is characterized and modeled using three dimensional simulation code written in Silvaco Atlas finite element analysis software. Calibrating the model to experimental data enables the extraction of device parameters such as material bandgaps, workfunctions, density of states, carrier mobilities, dielectric constants, and affinities. The sensitivity of our modeled PMC to the variation of its prominent achieved material parameters is examined on the HRS and LRS impedance behavior. The obtained accurate set of material parameters for both Ag-rich and Ag-poor ChG systems and process variation verification on electrical characteristics enables greater fidelity in PMC device simulation, which significantly enhances our ability to understand the underlying physics of

  4. Tolerant chalcogenide cathodes of membraneless micro fuel cells.

    Science.gov (United States)

    Gago, Aldo Saul; Gochi-Ponce, Yadira; Feng, Yong-Jun; Esquivel, Juan Pablo; Sabaté, Neus; Santander, Joaquin; Alonso-Vante, Nicolas

    2012-08-01

    The most critical issues to overcome in micro direct methanol fuel cells (μDMFCs) are the lack of tolerance of the platinum cathode and fuel crossover through the polymer membrane. Thus, two novel tolerant cathodes of a membraneless microlaminar-flow fuel cell (μLFFC), Pt(x)S(y) and CoSe(2), were developed. The multichannel structure of the system was microfabricated in SU-8 polymer. A commercial platinum cathode served for comparison. When using 5 M CH(3)OH as the fuel, maximum power densities of 6.5, 4, and 0.23 mW cm(-2) were achieved for the μLFFC with Pt, Pt(x)S(y), and CoSe(2) cathodes, respectively. The Pt(x)S(y) cathode outperformed Pt in the same fuel cell when using CH(3)OH at concentrations above 10 M. In a situation where fuel crossover is 100 %, that is, mixing the fuel with the reactant, the maximum power density of the micro fuel cell with Pt decreased by 80 %. However, for Pt(x)S(y) this decrease corresponded to 35 % and for CoSe(2) there was no change in performance. This result is the consequence of the high tolerance of the chalcogenide-based cathodes. When using 10 M HCOOH and a palladium-based anode, the μLFFC with a CoSe(2) cathode achieved a maxiumum power density of 1.04 mW cm(-2). This micro fuel cell does not contain either Nafion membrane or platinum. We report, for the first time, the evaluation of Pt(x)S(y)- and CoSe(2)-based cathodes in membraneless micro fuel cells. The results suggest the development of a novel system that is not size restricted and its operation is mainly based on the selectivity of its electrodes.

  5. Localized rapid heating process for precision chalcogenide glass molding

    Science.gov (United States)

    Li, Hui; He, Peng; Yu, Jianfeng; Lee, L. James; Yi, Allen Y.

    2015-10-01

    Precision glass molding is an important process for high volume optical fabrication. However, conventional glass molding is a bulk heating process that usually requires a long thermal cycle, where molding assembly and other mechanical parts are heated and cooled together. This often causes low efficiency and other heating and cooling related problems, such as large thermal expansion in both the molds and molded optics. To cope with this issue, we developed a localized rapid heating process to effectively heat only very small part of the glass. This localized rapid heating study utilized a fused silica wafer coated with a thin graphene layer to heat only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating heat on and near the coating. The feasibility of this process was validated by both experiments and numerical simulation. To demonstrate the advantages of the localized rapid heating, both localized rapid heating process and bulk heating process were performed and carefully compared. The uniformity and quality of the molded sample by localized rapid heating process was also demonstrated. In summary, localized rapid heating process by using graphene coated fused silica wafer was characterized and can be readily implemented in replication of micro scale chalcogenide glasses. A fused silica wafer coated with a thin graphene layer was utilized for localized rapid heating only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating high temperature on and near the coating. This process is fast and efficient since only interested areas are heated without affecting the entire glass substrate or the mold assembly. The uniformity and quality of the molded sample by localized rapid heating process was demonstrated by comparing both localized rapid heating

  6. Mercury's Crater-Hosted Hollows: Chalcogenide Pryo-Thermokarst, and Permafrost Analogs on Earth, Mars, and Titan

    Science.gov (United States)

    Kargel, Jeffrey

    2013-04-01

    MESSENGER has acquired stunning images of pitted, light-toned and variegated light/dark terrains located primarily on the floors—probably impact-melt sheets—of many of Mercury's large craters. Termed "hollows", the pitted terrains are geomorphologically similar to some on Mars formed by sublimation of ice-rich permafrost and to lowland thermokarst on Earth formed by permafrost thaw; to "swiss cheese" terrain forming by sublimation of frozen CO2 at the Martian South Pole; and to suspected hydrocarbon thermokarst at Titan's poles. I shall briefly review some analogs on these other worlds. The most plausible explanation for Mercury's hollows is terrain degradation involving melting or sublimation of heterogeneous chalcogenide and sulfosalt mineral assemblages. I refer to these Mercurian features as pyrothermokarst; the etymological redundancy distinguishes the conditions and mineral agents from the ice-related features on Earth and Mars, though some of the physical processes may be similar. Whereas ice and sulfur have long been suspected and ice recently was discovered in permanently shadowed craters of Mercury's polar regions, the hollows occur down to the equator, where neither ice nor sulfur is plausible. The responsible volatiles must be only slightly volatile on the surface and/or in the upper crust of Mercury's low to middle latitudes at 400-800 K, but they must be capable of either melting or sublimating on geologically long time scales. Under prevailing upper crustal and surface temperatures, chalcophile-rich "permafrost" can undergo either desulfidation or melting reactions that could cause migration or volume changes of the permafrost, and hence lead to collapse and pitting. I propose the initial emplacement of crater-hosted chalcogenides, sulfosalts and related chalcophile materials such as pnictides, in impact-melt pools (involving solid-liquid and silicate-sulfide fractionation) and further differentiation by associated dry or humid fumaroles (solid

  7. THz waveguides, devices and hybrid polymer-chalcogenide photonic crystal fibers

    DEFF Research Database (Denmark)

    Bao, Hualong; Markos, Christos; Nielsen, Kristian;

    2014-01-01

    In this contribution, we review our recent activities in the design, fabrication and characterization of polymer THz waveguides. Besides the THz waveguides, we finally will also briefly show some of our initial results on a novel hybrid polymer photonic crystal fiber with integrated chalcogenide...

  8. Bandgap Control via Structural and Chemical Tuning of Transition Metal Perovskite Chalcogenides.

    Science.gov (United States)

    Niu, Shanyuan; Huyan, Huaixun; Liu, Yang; Yeung, Matthew; Ye, Kevin; Blankemeier, Louis; Orvis, Thomas; Sarkar, Debarghya; Singh, David J; Kapadia, Rehan; Ravichandran, Jayakanth

    2017-03-01

    Transition metal perovskite chalcogenides are a new class of versatile semiconductors with high absorption coefficient and luminescence efficiency. Polycrystalline materials synthesized by an iodine-catalyzed solid-state reaction show distinctive optical colors and tunable bandgaps across the visible range in photoluminescence, with one of the materials' external efficiency approaching the level of single-crystal InP and CdSe.

  9. Native metastability in chalcogenide glasses described within configuration-coordinate model

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, M [Institute of Materials of Scientific Research Company ' Carat' , 202, Stryjska str., Lviv (Ukraine); Vakiv, M [Institute of Materials of Scientific Research Company ' Carat' , 202, Stryjska str., Lviv (Ukraine)

    2007-08-15

    It was created configuration-coordinate model for describing of native metastability in chalcogenide glasses. It was shown that potential should be at least triple-well. System of differential equations for describing transitions between the atomic states was made and solved within present configuration-coordinate model.

  10. Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, Marissa A.; Albers, Aaron E.; Levy, Seth C.; Pick, Teresa E.; Cohen, Bruce E.; Helms, Brett A.; Milliron, Delia J.

    2010-11-11

    A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.

  11. Small core Chalcogenide photonic crystal fiber for midinfrared wavelength conversion: experiment and design

    OpenAIRE

    Xing, Sida; Grassani, Davide; Kharitonov, Svyatoslav; Billat, Adrien; Brès, Camille-Sophie

    2016-01-01

    Kerr index and dispersion parameter of a small core chalcogenide photonic crystal fiber are estimated via four-wave mixing near 2μm. From these values, new fiber design is proposed to efficiently generate idlers in mid-infrared.

  12. Origin of the frequency shift of Raman scattering in chalcogenide glasses

    DEFF Research Database (Denmark)

    Han, X.C.; Tao, H.Z.; Gong, L.J.;

    2014-01-01

    Raman scattering is a sensitive method for probing the structural evolution in glasses, especially in covalent ones. Usually the main Raman scattering frequency shifts with composition for Gesingle bondSe chalcogenide glasses. However, it has not been well established whether and how the dependen...

  13. Mechanism for resistive switching in chalcogenide-based electrochemical metallization memory cells

    Directory of Open Access Journals (Sweden)

    Fei Zhuge

    2015-05-01

    Full Text Available It has been reported that in chalcogenide-based electrochemical metallization (ECM memory cells (e.g., As2S3:Ag, GeS:Cu, and Ag2S, the metal filament grows from the cathode (e.g., Pt and W towards the anode (e.g., Cu and Ag, whereas filament growth along the opposite direction has been observed in oxide-based ECM cells (e.g., ZnO, ZrO2, and SiO2. The growth direction difference has been ascribed to a high ion diffusion coefficient in chalcogenides in comparison with oxides. In this paper, upon analysis of OFF state I–V characteristics of ZnS-based ECM cells, we find that the metal filament grows from the anode towards the cathode and the filament rupture and rejuvenation occur at the cathodic interface, similar to the case of oxide-based ECM cells. It is inferred that in ECM cells based on the chalcogenides such as As2S3:Ag, GeS:Cu, and Ag2S, the filament growth from the cathode towards the anode is due to the existence of an abundance of ready-made mobile metal ions in the chalcogenides rather than to the high ion diffusion coefficient.

  14. High Average Power Mid-infrared Supercontinuum Generation in a Suspended Core Chalcogenide Fiber

    DEFF Research Database (Denmark)

    Møller, Uffe Visbech; Yu, Yi; Petersen, Christian Rosenberg;

    2014-01-01

    Mid-infrared supercontinuum spanning from 2.0 to 6.1 μm is generated in a 9 cm suspended core chalcogenide fiber by pumping close to the fiber zero-dispersion wavelength at 3.5 μm with an OPA system...

  15. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  16. Laser annealing and defect study of chalcogenide photovoltaic materials

    Science.gov (United States)

    Bhatia, Ashish

    Cu(In,Ga)Se2 (CIGSe), CuZnSn(S,Se)4(CZTSSe), etc., are the potential chalcogenide semiconductors being investigated for next-generation thin film photovoltaics (TFPV). While the champion cell efficiency of CIGSe has exceeded 20%, CZTSSe has crossed the 10% mark. This work investigates the effect of laser annealing on CISe films, and compares the electrical characteristics of CIGSe (chalcopyrite) and CZTSe (kesterite) solar cells. Chapter 1 through 3 provide a background on semiconductors and TFPV, properties of chalcopyrite and kesterite materials, and their characterization using deep level transient spectroscopy (DLTS) and thermal admittance spectroscopy (TAS). Chapter 4 investigates electrochemical deposition (nonvacuum synthesis) of CISe followed by continuous wave laser annealing (CWLA) using a 1064 nm laser. It is found that CWLA at ≈ 50 W/cm2 results in structural changes without melting and dewetting of the films. While Cu-poor samples show about 40% reduction in the full width at half maximum of the respective x-ray diffraction peaks, identically treated Cu-rich samples register more than 80% reduction. This study demonstrates that an entirely solid-phase laser annealing path exists for chalcopyrite phase formation and crystallization. Chapter 5 investigates the changes in defect populations after pulse laser annealing in submelting regime of electrochemically deposited and furnace annealed CISe films. DLTS on Schottky diodes reveal that the ionization energy of the dominant majority carrier defect state changes nonmonotonically from 215+/-10 meV for the reference sample, to 330+/-10 meV for samples irradiated at 20 and 30 mJ/cm2, and then back to 215+/-10 meV for samples irradiated at 40 mJ/cm2. A hypothesis involving competing processes of diffusion of Cu and laser-induced generation of In vacancies may explain this behavior. Chapter 6 compares the electrical characteristics of chalcopyrite and kesterite materials. Experiments reveal CZTSe cell has an

  17. Transition metal chalcogenides: ultrathin inorganic materials with tunable electronic properties.

    Science.gov (United States)

    Heine, Thomas

    2015-01-20

    CONSPECTUS: After the discovery of graphene and the development of powerful exfoliation techniques, experimental preparation of two-dimensional (2D) crystals can be expected for any layered material that is known to chemistry. Besides graphene and hexagonal boron nitride (h-BN), transition metal chalcogenides (TMC) are among the most studied ultrathin materials. In particular, single-layer MoS2, a direct band gap semiconductor with ∼1.9 eV energy gap, is popular in physics and nanoelectronics, because it nicely complements semimetallic graphene and insulating h-BN monolayer as a construction component for flexible 2D electronics and because it was already successfully applied in the laboratory as basis material for transistors and other electronic and optoelectronic devices. Two-dimensional crystals are subject to significant quantum confinement: compared with their parent layered 3D material, they show different structural, electronic, and optical properties, such as spontaneous rippling as free-standing monolayer, significant changes of the electronic band structure, giant spin-orbit splitting, and enhanced photoluminescence. Most of those properties are intrinsic for the monolayer and already absent for two-layer stacks of the same 2D crystal. For example, single-layer MoS2 is a direct band gap semiconductor with spin-orbit splitting of 150 meV in the valence band, while the bilayer of the same material is an indirect band gap semiconductor without observable spin-orbit splitting. All these properties have been observed experimentally and are in excellent agreement with calculations based on density-functional theory. This Account reports theoretical studies of a subgroup of transition metal dichalcogenides with the composition MX2, with M = Mo, or W and X = Se or S, also referred to as "MoWSeS materials". Results on the electronic structure, quantum confinement, spin-orbit coupling, spontaneous monolayer rippling, and change of electronic properties in the

  18. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells.

    Science.gov (United States)

    Freitas, Jilian N; Gonçalves, Agnaldo S; Nogueira, Ana F

    2014-06-21

    In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed.

  19. Photoinduced Operation by Absorption of the Chalcogenide Nanocrystallite Containing Solar Cells

    Directory of Open Access Journals (Sweden)

    Elnaggar A.M.

    2016-12-01

    Full Text Available It is shown that for the solar cells containing chalcogenide nanocrystallites using external laser light, one can achieve some enhancement of the photovoltaic efficiency. Photoinduced treatment was carried out using two beams of splitted Er: glass laser operating at 1.54 μm. The light of the laser was incident at different angles and the angles between the beams also were varied. Also, the studies of nanocomposite effective structures have shown enhancement of effective nanocrystalline sizes during the laser treatment. Nanocrystallites of CuInS2 and CuZnSnS4 (CZTS were used as chalcogenide materials. The optimization of the laser beam intensities and nanoparticle sizes were explored.

  20. Prediction of free-volume-type correlations in glassy chalcogenides from positron annihilation lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O., E-mail: shpotyuk@novas.lviv.ua [Institute of Materials of SRC “Carat”, 212 Stryjska Str., Lviv 79031 (Ukraine); Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestcochowa 42200 (Poland); Ingram, A. [Opole University of Technology, 75 Ozimska Str., Opole 45370 (Poland); Shpotyuk, M. [Institute of Materials of SRC “Carat”, 212 Stryjska Str., Lviv 79031 (Ukraine); Lviv Polytechnic National University, 12 Bandery Str., Lviv 79013 (Ukraine); Filipecki, J. [Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestcochowa 42200 (Poland)

    2014-11-01

    Highlights: • Decisive role of specific chemical environment in free-volume correlations in glass. • Realistic free volumes in As–S/Se glass are defined by newly modified τ{sub 2}-R formula. • Overestimated void sizes in chalcogenide glass as compared with molecular polymers. - Abstract: A newly modified correlation equation between defect-related positron lifetime determined within two-state trapping model and radius of corresponding free-volume-type defects was proposed to describe compositional variations in atomic-deficient structure of covalent-bonded chalcogenides like binary As–S/Se glasses. Specific chemical environment of free-volume voids around neighboring network-forming polyhedrons was shown to play a decisive role in this correlation, leading to systematically enhanced volumes in comparison with typical molecular substrates, such as polymers.

  1. Origin of resistivity anomaly in p-type leads chalcogenide multiphase compounds

    Energy Technology Data Exchange (ETDEWEB)

    Aminorroaya Yamini, Sima, E-mail: sima@uow.edu.au, E-mail: jsnyder@caltech.edu; Dou, Shi Xue [Australian Institute for Innovative Materials (AIIM), Innovation Campus, University of Wollongong, NSW 2500 (Australia); Mitchell, David R. G. [Electron Microscopy Centre (EMC), Australian Institute for Innovative Materials (AIIM), Innovation Campus, University of Wollongong, NSW 2500 (Australia); Wang, Heng [Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States); Gibbs, Zachary M. [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (United States); Pei, Yanzhong [School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804 (China); Snyder, G. Jeffrey, E-mail: sima@uow.edu.au, E-mail: jsnyder@caltech.edu [Electron Microscopy Centre (EMC), Australian Institute for Innovative Materials (AIIM), Innovation Campus, University of Wollongong, NSW 2500 (Australia); ITMO University, Saint Petersburg (Russian Federation)

    2015-05-15

    The electrical resistivity curves for binary phase compounds of p-type lead chalcogenide (PbTe){sub (0.9−x)}(PbSe){sub 0.1}(PbS){sub x,} (x = 0.15, 0.2, 0.25), which contain PbS-rich secondary phases, show different behaviour on heating and cooling between 500-700 K. This is contrast to single phase compounds which exhibit similar behaviour on heating and cooling. We correlate these anomalies in the electrical resistivities of multiphase compounds to the variation in phase composition at high temperatures. The inhomogeneous distribution of dopants between the matrix and secondary phase is found to be crucial in the electronic transport properties of the multiphase compounds. These results can lead to further advances in designing composite Pb-chalcogenides with high thermoelectric performance.

  2. Enhancing extraction efficiency of mid-infrared fluorescence in chalcogenide glass via photonic crystal

    Science.gov (United States)

    Zhang, Jun; Zhang, Peiqing; Ma, Beijiao; Dai, Shixun; Zhang, Wei; Nie, Qiuhua

    2016-04-01

    The use of rare earth-doped chalcogenide glass is an attractive method to develop mid-infrared sources. In this work, Er3+-doped chalcogenide glass is prepared, and photonic crystal (PC) pattern is designed to improve the extraction efficiency of light emission from the sample surface. The finite difference time domain simulation shows that the light extraction efficiency from the sample surface can be 1.62 times stronger than that from the sample without PC structure by introducing a simple two-dimensional (2D) PC structure into glass samples. This improvement was the result of the efficient light diffraction on the surface because of the integrated 2D PC. Results in this work offer a potential in developing midinfrared light sources.

  3. Low-power Mid-IR Supercontinuum and Rogue Wave Generation in Chalcogenide Waveguides

    CERN Document Server

    Hernandez, Santiago M; Bonetti, Juan; Grosz, Diego F

    2016-01-01

    We present numerical results of supercontinuum (SC) generation in the mid-IR spectral region, specifically addressing the molecular fingerprint window ranging from 2.5 to 25 um. By solving the Generalized Nonlinear Schr\\"odinger Equation (GNLSE) in a chalcogenide waveguide, we demonstrate low-power SC generation beyond 10 um from a pump at 5 um. Further, we investigate the short-pulse and CW regimes, and show that a simple linear dispersion profile, applicable to a broad range of chalcogenide media, is sufficient to account for the broad SC generation, and yield rich pulse dynamics leading to the frequent occurrence of rogue wave events. Results are encouraging as they point to the feasibility of producing bright and coherent light, by means of single low-power tabletop laser pumping schemes, in a spectral region that finds applications in such diverse areas as molecular spectroscopy, metrology and tomography, among others, and that is not easily addressable with other light sources

  4. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells

    Science.gov (United States)

    Freitas, Jilian N.; Gonçalves, Agnaldo S.; Nogueira, Ana F.

    2014-05-01

    In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed.

  5. Trends in oxygen reduction and methanol activation on transition metal chalcogenides

    DEFF Research Database (Denmark)

    Tritsaris, Georgios; Nørskov, Jens Kehlet; Rossmeisl, Jan

    2011-01-01

    We use density functional theory calculations to study the oxygen reduction reaction and methanol activation on selenium and sulfur-containing transition metal surfaces. With ruthenium selenium as a starting point, we study the effect of the chalcogen on the activity, selectivity and stability...... of the catalyst. Ruthenium surfaces with moderate content of selenium are calculated active for the oxygen reduction reaction, and insensitive to methanol. A significant upper limit for the activity of transition metal chalcogenides is estimated....

  6. Photoinduced Operation by Absorption of the Chalcogenide Nanocrystallite Containing Solar Cells

    OpenAIRE

    Elnaggar A.M.; Albassam A.; Oźga K.; Jędryka J.; Szota M.; Myronchuk G.

    2016-01-01

    It is shown that for the solar cells containing chalcogenide nanocrystallites using external laser light, one can achieve some enhancement of the photovoltaic efficiency. Photoinduced treatment was carried out using two beams of splitted Er: glass laser operating at 1.54 μm. The light of the laser was incident at different angles and the angles between the beams also were varied. Also, the studies of nanocomposite effective structures have shown enhancement of effective nanocrystalline sizes ...

  7. Atomic Layering, Intermixing and Switching Mechanism in Ge-Sb-Te based Chalcogenide Superlattices

    OpenAIRE

    Xiaoming Yu; John Robertson

    2016-01-01

    GeSbTe-based chalcogenide superlattice (CSLs) phase-change memories consist of GeSbTe layer blocks separated by van der Waals bonding gaps. Recent high resolution electron microscopy found two types of disorder in CSLs, a chemical disorder within individual layers, and SbTe bilayer stacking faults connecting one block to an adjacent block which allows individual block heights to vary. The disorder requires a generalization of the previous switching models developed for CSL systems. Density fu...

  8. Atomic Layering, Intermixing and Switching Mechanism in Ge-Sb-Te based Chalcogenide Superlattices.

    OpenAIRE

    Yu, X.; Robertson, J

    2016-01-01

    GeSbTe-based chalcogenide superlattice (CSLs) phase-change memories consist of GeSbTe layer blocks separated by van der Waals bonding gaps. Recent high resolution electron microscopy found two types of disorder in CSLs, a chemical disorder within individual layers, and SbTe bilayer stacking faults connecting one block to an adjacent block which allows individual block heights to vary. The disorder requires a generalization of the previous switching models developed for CSL systems. Density fu...

  9. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

    1997-12-31

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  10. Radiation-induced effects in chalcogenide glasses: Topological mechanisms and application

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.I. E-mail: karat@ipm.lviv.ua

    2000-05-02

    Structural transformations in vitreous As{sub 2}S{sub 3}-based chalcogenide semiconducting glasses induced by {gamma}-irradiation have been considered on the basis of IR Fourier spectroscopy results as destruction-polymerization changes of the covalent chemical bonds, associated with specific coordination defects formation. The whole variety of these processes has been taken into account in order to construct the physically real variants of the radiation-induced structural changes.

  11. Positron lifetime study of native vacancy-like defects in chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Filipecki, J.; Shpotyuk, O.I. E-mail: shpotyuk@novas.lviv.ua; Kozdras, A.; Kovalskiy, A.P

    2003-11-01

    Modified model for positron annihilation in vitreous chalcogenide semiconductors is developed to explain a number of previously obtained results on positron lifetime measurements in glassy As-Ge-S of stoichiometric As{sub 2}S{sub 3}-GeS{sub 2} and non-stoichiometric As{sub 2}S{sub 3}-Ge{sub 2}S{sub 3} cut-sections.

  12. Energy band alignment in chalcogenide thin film solar cells from photoelectron spectroscopy.

    Science.gov (United States)

    Klein, Andreas

    2015-04-10

    Energy band alignment plays an important role in thin film solar cells. This article presents an overview of the energy band alignment in chalcogenide thin film solar cells with a particular focus on the commercially available material systems CdTe and Cu(In,Ga)Se2. Experimental results from two decades of photoelectron spectroscopy experiments are compared with density functional theory calculations taken from literature. It is found that the experimentally determined energy band alignment is in good agreement with theoretical predictions for many interfaces. These alignments, in particular the theoretically predicted alignments, can therefore be considered as the intrinsic or natural alignments for a given material combination. The good agreement between experiment and theory enables a detailed discussion of the interfacial composition of Cu(In,Ga)Se2/CdS interfaces in terms of the contribution of ordered vacancy compounds to the alignment of the energy bands. It is furthermore shown that the most important interfaces in chalcogenide thin film solar cells, those between Cu(In,Ga)Se2 and CdS and between CdS and CdTe are quite insensitive to the processing of the layers. There are plenty of examples where a significant deviation between experimentally-determined band alignment and theoretical predictions are evident. In such cases a variation of band alignment of sometimes more than 1 eV depending on interface preparation can be obtained. This variation can lead to a significant deterioration of device properties. It is suggested that these modifications are related to the presence of high defect concentrations in the materials forming the contact. The particular defect chemistry of chalcogenide semiconductors, which is related to the ionicity of the chemical bond in these materials and which can be beneficial for material and device properties, can therefore cause significant device limitations, as e.g. in the case of the CuInS2 thin film solar cells or for new

  13. Interfacial scanning tunneling spectroscopy (STS) of chalcogenide/metal hybrid nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Saad, Mahmoud M.; Abdallah, Tamer [Physics Department, Faculty of Science, Ain Shams University, Abbassia, Cairo (Egypt); Easawi, Khalid; Negm, Sohair [Department of Physics and Mathematics, Faculty of Engineering (Shoubra), Benha University (Egypt); Talaat, Hassan, E-mail: hassantalaat@hotmail.com [Physics Department, Faculty of Science, Ain Shams University, Abbassia, Cairo (Egypt)

    2015-05-15

    Graphical abstract: - Highlights: • Comparing band gaps values obtained optically with STS. • Comparing direct imaging with calculated dimensions. • STS determination of the interfacial band bending of metal/chalcogenide. - Abstract: The electronic structure at the interface of chalcogenide/metal hybrid nanostructure (CdSe–Au tipped) had been studied by UHV scanning tunneling spectroscopy (STS) technique at room temperature. This nanostructure was synthesized by a phase transfer chemical method. The optical absorption of this hybrid nanostructure was recorded, and the application of the effective mass approximation (EMA) model gave dimensions that were confirmed by the direct measurements using the scanning tunneling microscopy (STM) as well as the high-resolution transmission electron microscope (HRTEM). The energy band gap obtained by STS agrees with the values obtained from the optical absorption. Moreover, the STS at the interface of CdSe–Au tipped hybrid nanostructure between CdSe of size about 4.1 ± 0.19 nm and Au tip of size about 3.5 ± 0.29 nm shows a band bending about 0.18 ± 0.03 eV in CdSe down in the direction of the interface. Such a result gives a direct observation of the electron accumulation at the interface of CdSe–Au tipped hybrid nanostructure, consistent with its energy band diagram. The presence of the electron accumulation at the interface of chalcogenides with metals has an important implication for hybrid nanoelectronic devices and the newly developed plasmon/chalcogenide photovoltaic solar energy conversion.

  14. Generation of correlated photon pairs in a chalcogenide As2S3 waveguide

    CERN Document Server

    Xiong, C; Peruzzo, A; Lobino, M; Clark, A S; Choi, D -Y; Madden, S J; Natarajan, C M; Tanner, M G; Hadfield, R H; Dorenbos, S N; Zijlstra, T; Zwiller, V; Thompson, M G; Rarity, J G; Steel, M J; Luther-Davies, B; Eggleton, B J; O'Brien, J L

    2010-01-01

    We demonstrate the first 1550 nm correlated photon-pair source in an integrated glass platform-a chalcogenide As2S3 waveguide. A measured pair coincidence rate of 80 per second was achieved using 57 mW of continuous-wave pump. The coincidence to accidental ratio was shown to be limited by spontaneous Raman scattering effects that are expected to be mitigated by using a pulsed pump source.

  15. Large magnetoresistance in non-magnetic silver chalcogenides and new class of magnetoresistive compounds

    Science.gov (United States)

    Saboungi, Marie-Louis; Price, David C. L.; Rosenbaum, Thomas F.; Xu, Rong; Husmann, Anke

    2001-01-01

    The heavily-doped silver chalcogenides, Ag.sub.2+.delta. Se and Ag.sub.2+.delta. Te, show magnetoresistance effects on a scale comparable to the "colossal" magnetoresistance (CMR) compounds. Hall coefficient, magnetoconductivity, and hydrostatic pressure experiments establish that elements of narrow-gap semiconductor physics apply, but both the size of the effects at room temperature and the linear field dependence down to fields of a few Oersteds are surprising new features.

  16. ZnO and copper indium chalcogenide heterojunctions prepared by inexpensive methods

    Energy Technology Data Exchange (ETDEWEB)

    Berruet, M., E-mail: berruetm@gmail.com [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Di Iorio, Y. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Troviano, M. [Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas (PROBIEN, CONICET-UNCo), Buenos Aires 1400, Q8300IBX Neuquén (Argentina); Vázquez, M. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina)

    2014-12-15

    Solution-based techniques were used to prepare ZnO/CuIn(Se, S){sub 2} heterojunctions that serve as solar cell prototypes. A duplex layer of ZnO (compact + porous) was electrodeposited. Chalcogenide thin films were deposited using successive ionic layer adsorption and reaction method (SILAR). By subsequent thermal treatments in two different atmospheres, CuInSe{sub 2} (CISe) and CuInSe{sub 2−x}S{sub x} (CISeS) were obtained. The composition and morphology of the annealed films were characterized by GXRD, micro-Raman spectroscopy and SEM. Devices prepared with CISe and CISeS show a clear photo-response. The introduction of a buffer layer of TiO{sub 2} into the ZnO/chalcogenide interface was necessary to detect photocurrent. The presence of CISeS improves the response of the cell, with higher values of short circuit current density, open circuit potential and fill factor. These promising results show that it is possible to prepare photovoltaic heterojunctions by depositing chalcogenides onto porous ZnO substrates using low-cost solution-based techniques. - Highlights: • Heterojunctions that serve as solar cell prototypes were prepared using solution-based techniques. • The devices comprised a double layer of ZnO and CuInSe{sub 2} or CuInSe{sub 0.4}S{sub 1.6}. • A TiO{sub 2} buffer layer in the ZnO/chalcogenide interface is necessary to detect photocurrent. • The incorporation of S improved the response of the photovoltaic heterojunction.

  17. High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology

    Energy Technology Data Exchange (ETDEWEB)

    Bernacki, Bruce E.

    2012-10-05

    This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.

  18. Efficient and broadband optical parametric four wave mixing in chalcogenide-PMMA hybrid microwires

    CERN Document Server

    Ahmad, Raja

    2012-01-01

    The recent development of devices based on novel nonlinear materials like chalcogenides (ChGs), silicon (Si) and other semi-conductors has revolutionized the field of nonlinear photonics [1,2,3]. Among the nonlinear effects observed in these materials, four-wave mixing (FWM) is the process that finds the most applications including wavelength conversion [4], optical regeneration [5,6], optical delay [7], time-domain demultiplexing[8], temporal cloaking[9] and negative refraction[10]. Although FWM has been observed in several media including chalcogenides [11,12,13,14], silicon[15, 16], bismuth [17] and silica [18,19], there is a continued quest for devices that realize efficient and broadband FWM while offering compactness, low-power consumption and compatibility with optical fibers. Here, we demonstrate the fabrication of 10 cm long polymer cladded chalcogenide (As2Se3) microwires to realize FWM-led sub watt threshold (70-370 mW) wavelength conversion with a 12 dB bandwidth as broad as 190 nm, and conversion...

  19. Template-directed assembly of metal-chalcogenide nanocrystals into ordered mesoporous networks.

    Energy Technology Data Exchange (ETDEWEB)

    Vamvasakis, Ioannis; Subrahmanyam, Kota S.; Kanatzidis, Mercouri G.; Armatas, Gerasimos S.

    2015-04-01

    Although great progress in the synthesis of porous networks of metal and metal oxide nanoparticles with highly accessible pore surface and ordered mesoscale pores has been achieved, synthesis of assembled 3D mesostructures of metal-chalcogenide nanocrystals is still challenging. In this work we demonstrate that ordered mesoporous networks, which comprise well-defined interconnected metal sulfide nanocrystals, can be prepared through a polymer-templated oxidative polymerization process. The resulting self-assembled mesostructures that were obtained after solvent extraction of the polymer template impart the unique combination of light-emitting metal chalcogenide nanocrystals, three-dimensional open-pore structure, high surface area, and uniform pores. We show that the pore surface of these materials is active and accessible to incoming molecules, exhibiting high photocatalytic activity and stability, for instance, in oxidation of 1-phenylethanol into acetophenone. We demonstrate through appropriate selection of the synthetic components that this method is general to prepare ordered mesoporous materials from metal chalcogenide nanocrystals with various sizes and compositions.

  20. Inorganic Thin-film Sensor Membranes with PLD-prepared Chalcogenide Glasses: Challenges and Implementation

    Directory of Open Access Journals (Sweden)

    Michael J. Schöning

    2004-10-01

    Full Text Available Abstract: Chalcogenide glasses offer an excellent “challenge” for their use and implementation in sensor arrays due to their good sensor-specific advantages in comparison to their crystalline counterparts. This paper will give an introduction on the preparation of chalcogenide glasses in the thin-film state. First, single microsensors have been prepared with the methods of semiconductor technology. In a next step, three microsensors are implemented onto one single silicon substrate to an “one chip” sensor array. Different ionselective chalcogenide glass membranes (PbSAgIAs2S3, CdSAgIAs2S3, CuAgAsSeTe and TlAgAsIS were prepared by means of the pulsed laser deposition (PLD process. The different sensor membranes and structures have been physically characterized by means of Rutherford backscattering spectrometry, scanning electron microscopy and video microscopy. The electrochemical behavior has been investigated by potentiometric measurements.

  1. Synthesis and characterization of single-source molecular precursors for the preparation of metal chalcogenides

    Indian Academy of Sciences (India)

    Vimal K Jain

    2006-11-01

    Metal chalcogenides constitute an important family of functional materials. Subtle changes in shape, size and phase of these materials result in variations in physical properties (e.g. electronic and optical), which can be exploited for various technological applications. Several strategies have evolved recently for controlling shape, size and phase of these materials. This work discusses design and synthesis of single-source molecular precursors for the preparation of metal chalcogenides both in bulk and nano-size regime. Precursors for palladium chalcogenides, indium sulphides and II-VI materials are presented. Synthesis of a variety of palladium(II)/platinum(II) complexes with internally functionalised chalcogenolate ligands, selenocarboxylates; gallium and indium dithiolate complexes and zinc/cadmium/mercury complexes with N,N'-dimethylaminoalkylselenolate ligands and their characterization by NMR and X-ray crystallography are also discussed. Data on thermal behaviour of a few representative complexes, [Pd(SeCOAr)2(PR3)2], [PdCl(E∩N)(PR3)], [InMe2(S∩S)], [In(S∩S)3] and [M(E(CH2)NMe2)2] (M = Zn, Cd, Hg; = 2 or 3) are presented.

  2. Low threshold fiber taper coupled rare earth ion-doped chalcogenide microsphere laser

    Science.gov (United States)

    Li, Chao-Ran; Dai, Shi-Xun; Zhang, Qing-Yuan; Shen, Xiang; Wang, Xun-Si; Zhang, Pei-Qing; Lu, Lai-Wei; Wu, Yue-Hao; Lv, She-Qin

    2015-04-01

    We report the applications of a low-cost and environmentally friendly chalcogenide glass, 75GeS2-15Ga2S3-10CsI, in building active microsphere laser oscillators. A silica fiber taper is used as the coupling mechanism. With an 808-nm laser diode as a pump source, we show that a high-Q (˜ 6×104) laser mode could be obtained from a 75-μm diameter microsphere that is coupled with a 1.77-μm waist-diameter fiber taper. The threshold of the incident pump power is 1.39 mW, which is considerably lower than those of previously reported free-space coupled chalcogenide microsphere lasers. We also note an apparent enhancement in laser power generated from this chalcogenide microsphere laser. Project supported by the National Natural Science Foundation of China (Grant Nos. 61177087 and 61435009), the National Key Basic Research Program of China (Grant No. 2012CB722703), the Program for Innovative Research Team of Ningbo City, China (Grant No. 2009B21007) , the K. C. Wong Magna Fund in Ningbo University, the Open Fund of the State Key Laboratory of Luminescent Materials and Devices (South China University of Technology), China (Grant No. 2014-skllmd-01), and the Natural Science Foundation of Ningbo City, China (Grant No. 2014A610125).

  3. Mixed-metal chalcogenide tetrahedral clusters with an exo-polyhedral metal fragment.

    Science.gov (United States)

    Yuvaraj, K; Roy, Dipak Kumar; Anju, V P; Mondal, Bijnaneswar; Varghese, Babu; Ghosh, Sundargopal

    2014-12-07

    The reaction of metal carbonyl compounds with group 6 and 8 metallaboranes led us to report the synthesis and structural characterization of several novel mixed-metal chalcogenide tetrahedral clusters. Thermolysis of arachno-[(Cp*RuCO)2B2H6], 1, and [Os3(CO)12] in the presence of 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Os3(CO)9}S], 3, and [Cp*Ru(μ-H){Os3(CO)11}], 4. In a similar fashion, the reaction of [(Cp*Mo)2B5H9], 2, with [Ru3(CO)12] and 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Ru3(CO)9}S], 5, and conjuncto-[(Cp*Mo)2B5H8(μ-H){Ru3(CO)9}S], 6. Both compounds 3 and 5 can be described as 50-cve (cluster valence electron) mixed-metal chalcogenide clusters, in which a sulfur atom replaces one of the vertices of the tetrahedral core. Compounds 3 and 5 possess a [M3S] tetrahedral core, in which the sulfur is attached to an exo-metal fragment, unique in the [M3S] metal chalcogenide tetrahedral arrangements. All the compounds have been characterized by mass spectrometry, IR, and (1)H, (11)B and (13)C NMR spectroscopy in solution, and the solid state structures were unequivocally established by crystallographic analysis of compounds 3, 5 and 6.

  4. 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.

  5. Chemical Control of Plasmons in Metal Chalcogenide and Metal Oxide Nanostructures.

    Science.gov (United States)

    Mattox, Tracy M; Ye, Xingchen; Manthiram, Karthish; Schuck, P James; Alivisatos, A Paul; Urban, Jeffrey J

    2015-10-14

    The field of plasmonics has grown to impact a diverse set of scientific disciplines ranging from quantum optics and photovoltaics to metamaterials and medicine. Plasmonics research has traditionally focused on noble metals; however, any material with a sufficiently high carrier density can support surface plasmon modes. Recently, researchers have made great gains in the synthetic (both intrinsic and extrinsic) control over the morphology and doping of nanoscale oxides, pnictides, sulfides, and selenides. These synthetic advances have, collectively, blossomed into a new, emerging class of plasmonic metal chalcogenides that complement traditional metallic materials. Chalcogenide and oxide nanostructures expand plasmonic properties into new spectral domains and also provide a rich suite of chemical controls available to manipulate plasmons, such as particle doping, shape, and composition. New opportunities in plasmonic chalcogenide nanomaterials are highlighted in this article, showing how they may be used to fundamentally tune the interaction and localization of electromagnetic fields on semiconductor surfaces in a way that enables new horizons in basic research and energy-relevant applications.

  6. Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

    Directory of Open Access Journals (Sweden)

    Yongfeng Tong

    2016-02-01

    Full Text Available This report examines the assembly of chalcogenide organic molecules on various surfaces, focusing on cases when chemisorption is accompanied by carbon–chalcogen atom-bond scission. In the case of alkane and benzyl chalcogenides, this induces formation of a chalcogenized interface layer. This process can occur during the initial stages of adsorption and then, after passivation of the surface, molecular adsorption can proceed. The characteristics of the chalcogenized interface layer can be significantly different from the metal layer and can affect various properties such as electron conduction. For chalcogenophenes, the carbon–chalcogen atom-bond breaking can lead to opening of the ring and adsorption of an alkene chalcogenide. Such a disruption of the π-electron system affects charge transport along the chains. Awareness about these effects is of importance from the point of view of molecular electronics. We discuss some recent studies based on X-ray photoelectron spectroscopy that shed light on these aspects for a series of such organic molecules.

  7. Ultrafast Microwave Nano-manufacturing of Fullerene-Like Metal Chalcogenides

    Science.gov (United States)

    Liu, Zhen; Zhang, Lin; Wang, Ruigang; Poyraz, Selcuk; Cook, Jonathan; Bozack, Michael J.; Das, Siddhartha; Zhang, Xinyu; Hu, Liangbing

    2016-01-01

    Metal Chalcogenides (MCs) have emerged as an extremely important class of nanomaterials with applications ranging from lubrication to energy storage devices. Here we report our discovery of a universal, ultrafast (60 seconds), energy-efficient, and facile technique of synthesizing MC nanoparticles and nanostructures, using microwave-assisted heating. A suitable combination of chemicals was selected for reactions on Polypyrrole nanofibers (PPy-NF) in presence of microwave irradiation. The PPy-NF serves as the conducting medium to absorb microwave energy to heat the chemicals that provide the metal and the chalcogenide constituents separately. The MCs are formed as nanoparticles that eventually undergo a size-dependent, multi-stage aggregation process to yield different kinds of MC nanostructures. Most importantly, this is a single-step metal chalcogenide formation process that is much faster and much more energy-efficient than all the other existing methods and can be universally employed to produce different kinds of MCs (e.g., MoS2, and WS2). PMID:26931353

  8. 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

  9. Fabrication of an IR hollow-core Bragg fiber based on chalcogenide glass extrusion

    Science.gov (United States)

    Zhu, Minming; Wang, Xunsi; Pan, Zhanghao; Cheng, Ci; Zhu, Qingde; Jiang, Chen; Nie, Qiuhua; Zhang, Peiqing; Wu, Yuehao; Dai, Shixun; Xu, Tiefeng; Tao, Guangming; Zhang, Xianghua

    2015-05-01

    The theoretical analysis and experimental preparation of a hollow-core Bragg fiber based on chalcogenide glasses are demonstrated. The fiber has potential applications in bio-sensing and IR energy transmission. Two chalcogenide glasses with, respectively, high and low refractive indexes are investigated in detail for the fabrication of hollow-core Bragg fibers. The most appropriate structure is selected; this structure is composed of four concentric rings and a center air hole . Its band gap for the Bragg fiber is analyzed by the plane wave method. The chalcogenide glasses Ge15Sb20S58.5I13 and Ge15Sb10Se75 are chosen to extrude the robust multi-material glass preform with a specialized punch and glass container. The glass preform is simultaneously protected with a polyetherimide polymer. The hollow-core Bragg fibers are finally obtained after glass preform extrusion, fiber preform fabrication, and fiber drawing. Results showed that the fiber has a transparency window from 2.5 to 14 μm, including a low-loss transmission window from 10.5 to 12 μm. The location of this low-loss transmission window matches the predicted photonic band gap in the simulation.

  10. Ultrafast Microwave Nano-manufacturing of Fullerene-Like Metal Chalcogenides

    Science.gov (United States)

    Liu, Zhen; Zhang, Lin; Wang, Ruigang; Poyraz, Selcuk; Cook, Jonathan; Bozack, Michael J.; Das, Siddhartha; Zhang, Xinyu; Hu, Liangbing

    2016-03-01

    Metal Chalcogenides (MCs) have emerged as an extremely important class of nanomaterials with applications ranging from lubrication to energy storage devices. Here we report our discovery of a universal, ultrafast (60 seconds), energy-efficient, and facile technique of synthesizing MC nanoparticles and nanostructures, using microwave-assisted heating. A suitable combination of chemicals was selected for reactions on Polypyrrole nanofibers (PPy-NF) in presence of microwave irradiation. The PPy-NF serves as the conducting medium to absorb microwave energy to heat the chemicals that provide the metal and the chalcogenide constituents separately. The MCs are formed as nanoparticles that eventually undergo a size-dependent, multi-stage aggregation process to yield different kinds of MC nanostructures. Most importantly, this is a single-step metal chalcogenide formation process that is much faster and much more energy-efficient than all the other existing methods and can be universally employed to produce different kinds of MCs (e.g., MoS2, and WS2).

  11. Mineral bioprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Torma, A.E.

    1993-05-01

    In the last 25 years, the introduction of biotechnological methods in hydrometallurgy has created new opportunities and challenges for the mineral processing industry. This was especially true for the production of metal values from mining wastes and low-and-complex-grade mineral resources, which were considered economically not amenable for processing by conventional extraction methods. Using bio-assisted heap, dump and in-situ leaching technologies, copper and uranium extractions gained their first industrial applications. The precious metal industries were the next to adopt the bio-preoxidation technique in the extraction of gold from refractory sulfide-bearing ores and concentrates. A variety of other bioleaching opportunities exist for nickel, cobalt, cadmium and zinc sulfide leaching. Recently developed bioremediation methods and biosorption technologies have shown a good potential for industrial applications to remove trace heavy metal and radionuclide concentrations from contaminated soils, and mining and processing effluents.

  12. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    in the Indian Ocean. In both fields, hydrothermalism has ceased between 11.000 and 13.000 years ago. The first occurrence (Sonne Field, 2850 m water depth) is located in the 4th segment of the Central Indian Ridge, north of the Rodriguez Triple Junction... structures are composed of sulfides arising out from deep beneath the Earth' crust. These minerals have been dissolved in hot water (350ºC) under great pressures and temperatures. When the water that flows out through the mantle ejects at the mid ocean...

  13. Novel methanol-tolerant Ir-S/C chalcogenide electrocatalysts for oxygen reduction in DMFC fuel cell

    Institute of Scientific and Technical Information of China (English)

    Jingyu Ma; Desheng Ai; Xiaofeng Xie; Jianwei Guo

    2011-01-01

    Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur (Ir-S) chalcogenides with differ ent Ir/S atomic ratios, were synthesized via a precipitation method using H21rCI6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the IrxSl-x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvious agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction (ORR) and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell (DMFC) cathode applications.

  14. Thin film chemical sensors based on chalcogenide glasses for ''electronic tongue'' application

    Energy Technology Data Exchange (ETDEWEB)

    Mourzina, Yu.; Legin, A.V.; Vlasov, Yu.G. [Sankt-Peterburgskij Univ., St. Petersburg (Russian Federation). Kafedra Khimii; Schoening, M.J. [Forschungszentrum Juelich GmbH (Germany). Abt. Sicherheit und Strahlenschutz]|[Univ. of Applied Sciences Aachen, Juelich (Germany); Schubert, J.; Zander, W.; Lueth, H. [Forschungszentrum Juelich GmbH (Germany). Abt. Sicherheit und Strahlenschutz

    2001-07-01

    A novel thin film preparation method, a pulsed laser deposition (PLD) technique, has been used in the present investigation to realise thin film chalcogenide layers for chemical sensor membranes. This technique is compatible with silicon technology and was aimed at fabrication of primary devices for analytical microsystems for the needs of fast analysis and in-situ measurements. The combination of the new type of the potentiometric thin film sensor array based on chalcogenide glass materials and artificial neural network for the experimental data processing is also presented. (orig.)

  15. Compositional trends of γ-induced optical changes observed in chalcogenide glasses of binary As-S system

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, M.; Shpotyuk, O.; Golovchak, Roman; McCloy, John S.; Riley, Brian J.

    2014-01-23

    Compositional trends of γ-induced optical changes in chalcogenide glasses are studied with the binary As-S system. Effects of γ-irradiation and annealing are compared using the changes measured in the fundamental optical absorption edge region. It is shown that annealing near the glass transition temperature leads to bleaching of As-S glasses, while γ-irradiation leads to darkening; both depend on the glass composition and thermal history of the specimens. These results are explained in terms of competitive destruction–polymerization transformations and physical aging occurring in As-S chalcogenide glasses under the influence of γ-irradiation.

  16. A First Step Towards a Microfabricated Thin-Film Sensor Array on the Basis of Chalcogenide Glass Materials

    Directory of Open Access Journals (Sweden)

    Michael J. Schöning

    2002-09-01

    Full Text Available A first step towards a microfabricated potentiometric thin-film sensor array for the simultaneous detection of Pb2+, Cd2+ and Cu2+ has been realized. The sensitive layers used are on the basis of chalcogenide glass materials. These thin-film chalcogenide glass materials that consist of mixtures of Pb-Ag-As-I-S, Cd-Ag-As-I-S or Cu-Ag-As-Se have been prepared by pulsed laser deposition technique. The developed sensor array has been physically characterized by means of scanning electron microscopy and Rutherford backscattering spectrometry. The electrochemical sensor characterization has been performend by potentiometric measurements.

  17. Widely tunable second-harmonic generation in a chalcogenide-tellurite hybrid optical fiber.

    Science.gov (United States)

    Cheng, Tonglei; Gao, Weiqing; Kawashima, Hiroyasu; Deng, Dinghuan; Liao, Meisong; Matsumoto, Morio; Misumi, Takashi; Suzuki, Takenobu; Ohishi, Yasutake

    2014-04-01

    When a chalcogenide-tellurite hybrid optical fiber with a high refractive index difference Δn=0.24 is pumped by an optical parametric oscillator with a pump wavelength from 1700 to 3000 nm, widely tunable second-harmonic generation (SHG) from 850 to 1502 nm is obtained. The observation of SHG is primarily due to the surface nonlinearity polarization at the core-cladding interface and the second-harmonic signal remains stable at the maximal level throughout the laser pulse irradiation.

  18. Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C. C.

    2011-08-15

    Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.

  19. Demonstration of high-Q mid-infrared chalcogenide glass-on-silicon resonators.

    Science.gov (United States)

    Lin, Hongtao; Li, Lan; Zou, Yi; Danto, Sylvain; Musgraves, J David; Richardson, Kathleen; Kozacik, Stephen; Murakowski, Maciej; Prather, Dennis; Lin, Pao T; Singh, Vivek; Agarwal, Anu; Kimerling, Lionel C; Hu, Juejun

    2013-05-01

    We demonstrated high-index-contrast, waveguide-coupled As2Se3 chalcogenide glass resonators monolithically integrated on silicon fabricated using optical lithography and a lift-off process. The resonators exhibited a high intrinsic quality factor of 2×10(5) at 5.2 μm wavelength, which is among the highest values reported in on-chip mid-infrared (mid-IR) photonic devices. The resonator can serve as a key building block for mid-IR planar photonic circuits.

  20. Structural modification of covalent-bonded networks: on some methodological resolutions for binary chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, M; Shpotyuk, Ya; Shpotyuk, O, E-mail: shpotyukmy@yahoo.com [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 212, Stryjska str., Lviv, 79031 (Ukraine)

    2011-04-01

    New methodology to estimate efficiency of externally-induced structural modification in chalcogenide glasses is developed. This approach is grounded on the assumption that externally-induced structural modification is fully associated with destruction-polymerization transformations, which reveal themselves as local misbalances in covalent bond distribution, normal atomic coordination and intrinsic electrical fields. The input of each of these components into the total value of structural modification efficiency was probed for quasibinary (As{sub 2}S{sub 3}){sub 100-x}(Sb{sub 2}S{sub 3}){sub x} ChG.

  1. Radiation-induced defects in chalcogenide glasses characterized by combined optical spectroscopy, XPS and PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestochowa 42201 (Poland); Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Lviv Institute of Materials of SRC ' ' Carat' ' , 202, Stryjska str., 79031 Lviv (Ukraine); Kovalskiy, A.; Jain, H. [Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Golovchak, R. [Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Lviv Institute of Materials of SRC ' ' Carat' ' , 202, Stryjska str., 79031 Lviv (Ukraine); Zurawska, A. [Opole University of Technology, 75, Ozimska str., Opole 45370 (Poland)

    2007-03-15

    Temperature-dependent optical absorption spectroscopy, high-resolution X-ray photoelectron spectroscopy and positron annihilation lifetimes spectroscopy are utilized to understand radiation-induced changes in Ge-Sb-S chalcogenide glasses. Theoretically predicted topological scheme of {gamma}-induced coordination defect formation in stoichiometric Ge{sub 23.5}Sb{sub 11.8}S{sub 64.7} glass composition is supported by these measurements. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Radiation-induced defects formation in Bi-containing vitreous chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.; Vakiv, M.; Balitska, V.; Kovalskiy, A. [Institute of Materials, Lvov (Ukraine)

    1997-12-01

    Processes of formation and annihilation of coordination defects in As{sub 2}Se{sub 3}Bi{sub y} and (As{sub 2}Se{sub 3})(Bi{sub 2}Se{sub 3}){sub y} amorphous chalcogenide semiconductors induced by influence of Co{sup 60} gamma-irradiation are investigated by photoelectric spectroscopy method. It is obtained that radiation-induced changes of photoelectrical properties on bioconcentration of As{sub 2}Se{sub 3}Bi{sub y} glasses are characterized by anomalous concentration dependence. The nature of this effect is associated with diamagnetic coordination defects formation. (author). 19 refs, 3 figs.

  3. Application of positron annihilation lifetime technique for {gamma}-irradiation stresses study in chalcogenide vitreous semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.; Golovchak, R.; Kovalskiy, A. [Scientific Research Company ' ' Carat' ' , Stryjska str. 20279031 Lviv (Ukraine); Filipecki, J.; Hyla, M. [Physics Institute, Pedagogical University, Al. Armii Krajowej 13/1542201 Czestochowa (Poland)

    2002-08-01

    The influence of {gamma}-irradiation on the positron annihilation lifetime spectra in chalcogenide vitreous semiconductors of As-Ge-S system has been analysed. The correlations between lifetime data, structural features and chemical compositions of glasses have been discussed. The observed lifetime components are connected with bulk positron annihilation and positron annihilation on various native and {gamma}-induced open volume defects. It is concluded that after {gamma}-irradiation of investigated materials the {gamma}-induced microvoids based on S{sub 1}{sup -}, As{sub 2}{sup -}, and Ge{sub 3}{sup -} coordination defects play the major role in positron annihilation processes. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  4. Charged defects in chalcogenide vitreous semiconductors studied with combined Raman scattering and PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Kavetskyy, T.; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)], E-mail: shpotyuk@novas.lviv.ua

    2007-04-15

    A combination of Raman scattering and positron annihilation lifetime spectroscopy (PALS) techniques to study charged defects in chalcogenide vitreous semiconductors (ChVSs) was applied for the first time in this study. In the case of Ge{sub 15.8}As{sub 21}S{sub 63.2} glass, it is found that the main radiation-induced switching of heteropolar Ge-S bonds into heteropolar As-S ones, previously detected by IR fast Fourier transform spectroscopy, can also be identified by Raman spectroscopy in the depolarized configuration. Results obtained by Raman scattering are in good agreement with PALS data for the investigated glass composition.

  5. The electronic structure of the antimony chalcogenide series: Prospects for optoelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Carey, John J.; Allen, Jeremy P. [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland); Scanlon, David O. [University College London, Kathleen Lonsdale Materials Chemistry, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Watson, Graeme W., E-mail: watsong@tcd.ie [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland)

    2014-05-01

    In this study, density functional theory is used to evaluate the electronic structure of the antimony chalcogenide series. Analysis of the electronic density of states and charge density shows that asymmetric density, or ‘lone pairs’, forms on the Sb{sup III} cations in the distorted oxide, sulphide and selenide materials. The asymmetric density progressively weakens down the series, due to the increase in energy of valence p states from O to Te, and is absent for Sb{sub 2}Te{sub 3}. The fundamental and optical band gaps were calculated and Sb{sub 2}O{sub 3}, Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} have indirect band gaps, while Sb{sub 2}Te{sub 3} was calculated to have a direct band gap at Γ. The band gaps are also seen to reduce from Sb{sub 2}O{sub 3} to Sb{sub 2}Te{sub 3}. The optical band gap for Sb{sub 2}O{sub 3} makes it a candidate as a transparent conducting oxide, while Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} have suitable band gaps for thin film solar cell absorbers. - Graphical abstract: A schematic illustrating the interaction between the Sb{sup III} cations and the chalcogenide anions and the change in their respective energy levels down the series. - Highlights: • The electronic structure of the antimony chalcogenide series is modelled using DFT. • Asymmetric density is present on distorted systems and absent on the symmetric telluride system. • Asymmetric density is formed from the mixing of Sb 5s and anion p states, where the anti-bonding combination is stabilised by the Sb 5p states. • The asymmetric density weakens down the series due to the increase in energy of chalcogenide p states. • The increase in energy of the anion p states reduces the fundamental and optical band gaps.

  6. Single Cell Element of Chalcogenide Random Access Memory Fabricated with the Focused Ion Beam Method

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; SONG Zhi-Tang; FENG Song-Lin; CHEN Bomy

    2004-01-01

    A single cell element of chalcogenide random access memory was fabricated by using the focused ion beam method. The contact size between the Ge2Sb2 Te5 phase change film and the top electrode film is about 600nm (diameter) and the contact area is calculated to be 0.28pm2. The thickness of the phase change film is 83nm.The current-voltage characteristics of the cell element are studied using the home-made current-voltage tester in our laboratory. The minimum threshold current of about 0.6mA is obtained.

  7. Broadband terahertz spectroscopy of chalcogenide glass As30Se30Te40

    DEFF Research Database (Denmark)

    Wang, Tianwu; Romonova, Elena A.; Abdel-Moneim, Nabil

    2016-01-01

    Broadband terahertz time domain spectroscopy (THz-TDS) and time resolved terahertz spectroscopy (TRTS) were performed on a 54 μm thick chalcogenide glass (As30Se30Te40) sample using a two-color laser induced air plasma THz system in transmission and reflection configurations, respectively. Two...... absorption modes were observed at 2–3 THz and 5–8 THz. The photo-induced conductivity can be well described by the Drude-Smith conductivity model, which shows significant carrier localization effects. A fast refractive index change was observed 100 fs before the conductivity reached its maximum with two...

  8. Observation of nonlinear thermal optical dynamics in a chalcogenide nanobeam cavity

    CERN Document Server

    Sun, Yue; Choi, Duk-Yong; Sukhorukov, Andrey A

    2016-01-01

    We present a theoretical and experimental analysis of nonlinear thermo-optic effects in suspended chalcogenide glass nanobeam cavities. We measure the power dependent resonance peaks and characterise the dynamic nonlinear thermo-optic response of the cavity under modulated light input. Several distinct nonlinear characteristics are identified, including a modified spectral response containing periodic fringes, a critical wavelength jump and saturated time delay for modulation frequency faster than the thermal characteristic time. We reveal that the coupling to a parasitic Fabry-Perot cavity enables isolated thermal equilibrium states resulting in the discontinuous thermo-optic critical point.

  9. Chalcogenide Random Access Memory Cell with Structure of W Sub-Microtube Heater Electrode

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; FENG Gao-Ming; WU Liang-Cai; SONG Zhi-Tang; LIU Qi-Bin; FENG Song-Lin; CHEN Bomy

    2007-01-01

    @@ In order to reduce the reset current of chalcogenide random access memory, a W sub-microtube heater electrode with outer/inner diameter of 260/100nm, which was fabricated with standard 0.18-μm technology, is proposed for the first time to achieve a reset current of about 0.5mA. The reasons may be that sub-microtube increases the number of electrode edge and thermal efficiency is improved greatly because the thermal density on the edge of sub-microtube electrode is generally the highest.

  10. The electronic band structures of gadolinium chalcogenides: a first-principles prediction for neutron detecting

    Science.gov (United States)

    Li, Kexue; Liu, Lei; Yu, Peter Y.; Chen, Xiaobo; Shen, D. Z.

    2016-05-01

    By converting the energy of nuclear radiation to excited electrons and holes, semiconductor detectors have provided a highly efficient way for detecting them, such as photons or charged particles. However, for detecting the radiated neutrons, those conventional semiconductors hardly behave well, as few of them possess enough capability for capturing these neutral particles. While the element Gd has the highest nuclear cross section, here for searching proper neutron-detecting semiconductors, we investigate theoretically the Gd chalcogenides whose electronic band structures have never been characterized clearly. Among them, we identify that γ-phase Gd2Se3 should be the best candidate for neutron detecting since it possesses not only the right bandgap of 1.76 eV for devices working under room temperature but also the desired indirect gap nature for charge carriers surviving longer. We propose further that semiconductor neutron detectors with single-neutron sensitivity can be realized with such a Gd-chalcogenide on the condition that their crystals can be grown with good quality.

  11. Identification of Abnormal Phase and its Formation Mechanism in Synthesizing Chalcogenide Films

    Science.gov (United States)

    Liu, Kegao; Ji, Nianjing; Xu, Yong; Liu, Hong

    2016-09-01

    Chalcogenide films can be used in thin-film solar cells due to their high photoelectric conversion efficiencies. It was difficult to identify one abnormal phase with high X-ray diffraction (XRD) intensity and preferred orientation in the samples for preparing chalcogenide films by spin-coating and co-reduction on soda-lime glass (Na2OṡCaOṡ6SiO2) substrates. The raw materials and reductant are metal chlorides and hydrazine hydrate respectively. In order to identify this phase, a series of experiments were done under different conditions. The phases of obtained products were analyzed by XRD and the size and morphology were characterized by scanning electron microscope (SEM) and atomic force microscopy (AFM). From the experimental results, first it was proved that the abnormal phase was water-soluble by water immersion experiment, then it was identified as NaCl crystal through XRD, energy dispersive spectrometer (EDS) and SEM. The cubic NaCl crystals have high crystallinity with size lengths of about 0.5-2μm and show a preferred orientation. The reaction mechanism of NaCl crystal was proposed as follows: The NaCl crystal was formed by reaction of Na2O and HCl in a certain experimental conditions.

  12. Crystal symmetry breaking and vacancies in colloidal lead chalcogenide quantum dots

    Science.gov (United States)

    Bertolotti, Federica; Dirin, Dmitry N.; Ibáñez, Maria; Krumeich, Frank; Cervellino, Antonio; Frison, Ruggero; Voznyy, Oleksandr; Sargent, Edward H.; Kovalenko, Maksym V.; Guagliardi, Antonietta; Masciocchi, Norberto

    2016-09-01

    Size and shape tunability and low-cost solution processability make colloidal lead chalcogenide quantum dots (QDs) an emerging class of building blocks for innovative photovoltaic, thermoelectric and optoelectronic devices. Lead chalcogenide QDs are known to crystallize in the rock-salt structure, although with very different atomic order and stoichiometry in the core and surface regions; however, there exists no convincing prior identification of how extreme downsizing and surface-induced ligand effects influence structural distortion. Using forefront X-ray scattering techniques and density functional theory calculations, here we have identified that, at sizes below 8 nm, PbS and PbSe QDs undergo a lattice distortion with displacement of the Pb sublattice, driven by ligand-induced tensile strain. The resulting permanent electric dipoles may have implications on the oriented attachment of these QDs. Evidence is found for a Pb-deficient core and, in the as-synthesized QDs, for a rhombic dodecahedral shape with nonpolar {110} facets. On varying the nature of the surface ligands, differences in lattice strains are found.

  13. Silicon-based thin films as bottom electrodes in chalcogenide nonvolatile memories

    Science.gov (United States)

    Lee, Seung-Yun; Yoon, Sung-Min; Choi, Kyu-Jeong; Lee, Nam-Yeal; Park, Young-Sam; Ryu, Sang-Ouk; Yu, Byoung-Gon; Kim, Sang-Hoon; Lee, Sang-Heung

    2007-10-01

    The effect of the electrical resistivity of a silicon-germanium (SiGe) thin film on the phase transition in a GeSbTe (GST) chalcogenide alloy and the manufacturing aspect of the fabrication process of a chalcogenide memory device employing the SiGe film as bottom electrodes were investigated. While p-type SiGe bottom electrodes were formed using in situ doping techniques, n-type ones could be made in a different manner where phosphorus atoms diffused from highly doped silicon underlayers to undoped SiGe films. The p-n heterojunction did not form between the p-type GST and n-type SiGe layers, and the semiconduction type of the SiGe alloys did not influence the memory device switching. It was confirmed that an optimum resistivity value existed for memory operation in spite of proportionality of Joule heating to electrical resistivity. The very high resistivity of the SiGe film had no effect on the reduction of reset current, which might result from the resistance decrease of the SiGe alloy at high temperatures.

  14. Silicon-based thin films as bottom electrodes in chalcogenide nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Yun [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)], E-mail: seungyun@etri.re.kr; Yoon, Sung-Min; Choi, Kyu-Jeong; Lee, Nam-Yeal; Park, Young-Sam; Ryu, Sang-Ouk; Yu, Byoung-Gon; Kim, Sang-Hoon; Lee, Sang-Heung [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)

    2007-10-31

    The effect of the electrical resistivity of a silicon-germanium (SiGe) thin film on the phase transition in a GeSbTe (GST) chalcogenide alloy and the manufacturing aspect of the fabrication process of a chalcogenide memory device employing the SiGe film as bottom electrodes were investigated. While p-type SiGe bottom electrodes were formed using in situ doping techniques, n-type ones could be made in a different manner where phosphorus atoms diffused from highly doped silicon underlayers to undoped SiGe films. The p-n heterojunction did not form between the p-type GST and n-type SiGe layers, and the semiconduction type of the SiGe alloys did not influence the memory device switching. It was confirmed that an optimum resistivity value existed for memory operation in spite of proportionality of Joule heating to electrical resistivity. The very high resistivity of the SiGe film had no effect on the reduction of reset current, which might result from the resistance decrease of the SiGe alloy at high temperatures.

  15. Nanostructured metal chalcogenides: synthesis, modification, and applications in energy conversion and storage devices.

    Science.gov (United States)

    Gao, Min-Rui; Xu, Yun-Fei; Jiang, Jun; Yu, Shu-Hong

    2013-04-07

    Advanced energy conversion and storage (ECS) devices (including fuel cells, photoelectrochemical water splitting cells, solar cells, Li-ion batteries and supercapacitors) are expected to play a major role in the development of sustainable technologies that alleviate the energy and environmental challenges we are currently facing. The successful utilization of ECS devices depends critically on synthesizing new nanomaterials with merits of low cost, high efficiency, and outstanding properties. Recent progress has demonstrated that nanostructured metal chalcogenides (MCs) are very promising candidates for efficient ECS systems based on their unique physical and chemical properties, such as conductivity, mechanical and thermal stability and cyclability. In this review, we aim to provide a summary on the liquid-phase synthesis, modifications, and energy-related applications of nanostructured metal chalcogenide (MC) materials. The liquid-phase syntheses of various MC nanomaterials are primarily categorized with the preparation method (mainly 15 kinds of methods). To obtain optimized, enhanced or even new properties, the nanostructured MC materials can be modified by other functional nanomaterials such as carbon-based materials, noble metals, metal oxides, or MCs themselves. Thus, this review will then be focused on the recent strategies used to realize the modifications of MC nanomaterials. After that, the ECS applications of the MC/modified-MC nanomaterials have been systematically summarized based on a great number of successful cases. Moreover, remarks on the challenges and perspectives for future MC research are proposed (403 references).

  16. Structural and electronic properties of high pressure phases of lead chalcogenides

    Science.gov (United States)

    Petersen, John; Scolfaro, Luisa; Myers, Thomas

    2012-10-01

    Lead chalcogenides, most notably PbTe and PbSe, have become an active area of research due to their thermoelectric properties. The high figure of merit (ZT) of these materials has brought much attention to them, due to their ability to convert waste heat into electricity. Variation in synthesis conditions gives rise to a need for analysis of structural and thermoelectric properties of these materials at different pressures. In addition to the NaCl structure at ambient conditions, lead chalcogenides have a dynamic orthorhombic (Pnma) intermediate phase and a higher pressure yet stable CsCl phase. By altering the lattice constant, we simulate the application of external pressure; this has notable effects on ground state total energy, band gap, and structural phase. Using the General Gradient Approximation (GGA) in Density Functional Theory (DFT), we calculate the phase transition pressures by finding the differences in enthalpy from total energy calculations. For each phase, elastic constants, bulk modulus, shear modulus, Young's modulus, and hardness are calculated, using two different approaches. In addition to structural properties, we analyze the band structure and density of states at varying pressures, paying special note to thermoelectric implications.

  17. Random free energy barrier hopping model for ac conduction in chalcogenide glasses

    Science.gov (United States)

    Murti, Ram; Tripathi, S. K.; Goyal, Navdeep; Prakash, Satya

    2016-03-01

    The random free energy barrier hopping model is proposed to explain the ac conductivity (σac) of chalcogenide glasses. The Coulomb correlation is consistently accounted for in the polarizability and defect distribution functions and the relaxation time is augmented to include the overlapping of hopping particle wave functions. It is observed that ac and dc conduction in chalcogenides are due to same mechanism and Meyer-Neldel (MN) rule is the consequence of temperature dependence of hopping barriers. The exponential parameter s is calculated and it is found that s is subjected to sample preparation and measurement conditions and its value can be less than or greater than one. The calculated results for a - Se, As2S3, As2Se3 and As2Te3 are found in close agreement with the experimental data. The bipolaron and single polaron hopping contributions dominates at lower and higher temperatures respectively and in addition to high energy optical phonons, low energy optical and high energy acoustic phonons also contribute to the hopping process. The variations of hopping distance with temperature is also studied. The estimated defect number density and static barrier heights are compared with other existing calculations.

  18. Investigation of Optical Nonlinearities in Bi-Doped Se-Te Chalcogenide Thin Films

    Science.gov (United States)

    Yadav, Preeti; Sharma, Ambika

    2015-03-01

    The present paper reports the nonlinear optical properties of chalcogenide Se85- x Te15Bi x (0 ≤ x ≤ 5) thin films. The formulation proposed by Boling, Fournier, and Snitzer and Tichy and Ticha has been used to compute the nonlinear refractive index n 2. The two-photon absorption coefficient β 2, and first- and third-order susceptibilities [ χ (1) and χ (3)] are also reported. The nonlinear refractive index n 2 is well correlated with the linear refractive index n and Wemple-DiDomenico (WDD) parameters, in turn depending on the density ρ and molar volume V m of the system. The density of the system is calculated experimentally by using Archimedes' principle. The linear optical parameters, viz. n, WDD parameters, and optical bandgap E g, are measured experimentally using ellipsometric curves obtained by spectrophotometry. The composition-dependent behavior of n 2 is analyzed on the basis of various parameters, viz. density, bond distribution, cohesive energy (CE), and optical bandgap E g, of the system. The variation of n 2 and β 2 with changing bandgap E g is also reported. The values of n 2 and χ (3) of the investigated chalcogenides are compared with those of pure silica, oxide, and other Se-based glasses.

  19. Photonic Bandgap Propagation in All-Solid Chalcogenide Microstructured Optical Fibers

    Directory of Open Access Journals (Sweden)

    Celine Caillaud

    2014-08-01

    Full Text Available An original way to obtain fibers with special chromatic dispersion and single-mode behavior is to consider microstructured optical fibers (MOFs. These fibers present unique optical properties thanks to the high degree of freedom in the design of their geometrical structure. In this study, the first all-solid all-chalcogenide MOFs exhibiting photonic bandgap transmission have been achieved and optically characterized. The fibers are made of an As38Se62 matrix, with inclusions of Te20As30Se50 glass that shows a higher refractive index (n = 2.9. In those fibers, several transmission bands have been observed in mid infrared depending on the geometry. In addition, for the first time, propagation by photonic bandgap effect in an all-chalcogenide MOF has been observed at 3.39 µm, 9.3 µm, and 10.6 µm. The numerical simulations based on the optogeometric properties of the fibers agree well with the experimental characterizations.

  20. Mid-gap phenomena in chalcogenide glasses and barrier-cluster-heating model

    Energy Technology Data Exchange (ETDEWEB)

    Banik, Ivan, E-mail: ivan.banik@stuba.sk; Kubliha, Marián; Lukovičová, Jozefa; Pavlendová, Gabriela [Faculty of Civil Engineering, Slovak University of Technology, 813 68 Bratislava (Slovakia)

    2015-12-07

    The physical mechanism of photoluminescence spectrum formation of chalcogenide glasses (CHG) belongs to the important unsolved problems in physics of non-crystalline materials. Photoluminescence is an important means of the electron spectrum investigation. PL spectrum in CHG is produced mostly in the middle of the band gap, and its profile is normal - Gaussian. Several features of PL spectra in CHG is still a great mystery. The aim of the paper is to make reader acquainted with the new insight into the problem. In this article we also deal with the issue of clarifying the nature of mid-gap absorption. From the experiments it is known that after excitation of the glass As{sub 2}S{sub 3} (or As{sub 2}Se{sub 3}) with primary radiation from Urbach-tail region the glass will be able to absorb the photons of low energy (IR) radiation from mid-gap region of spectra. This low photon absorption without action of the primary excitation radiation of the higher photon energy is impossible. Mid-gap absorption yields boost in the photoluminescence. The paper gives the reader the new insights into some, until now, unexplained effects and contexts in chalcogenide glasses from the position of barrier-cluster-heating model.

  1. Interface control by homoepitaxial growth in pulsed laser deposited iron chalcogenide thin films

    Science.gov (United States)

    Molatta, Sebastian; Haindl, Silvia; Trommler, Sascha; Schulze, Michael; Wurmehl, Sabine; Hühne, Ruben

    2015-11-01

    Thin film growth of iron chalcogenides by pulsed laser deposition (PLD) is still a delicate issue in terms of simultaneous control of stoichiometry, texture, substrate/film interface properties, and superconducting properties. The high volatility of the constituents sharply limits optimal deposition temperatures to a narrow window and mainly challenges reproducibility for vacuum based methods. In this work we demonstrate the beneficial introduction of a semiconducting FeSe1-xTex seed layer for subsequent homoepitaxial growth of superconducting FeSe1-xTex thin film on MgO substrates. MgO is one of the most favorable substrates used in superconducting thin film applications, but the controlled growth of iron chalcogenide thin films on MgO has not yet been optimized and is the least understood. The large mismatch between the lattice constants of MgO and FeSe1-xTex of about 11% results in thin films with a mixed texture, that prevents further accurate investigations of a correlation between structural and electrical properties of FeSe1-xTex. Here we present an effective way to significantly improve epitaxial growth of superconducting FeSe1-xTex thin films with reproducible high critical temperatures (≥17 K) at reduced deposition temperatures (200 °C-320 °C) on MgO using PLD. This offers a broad scope of various applications.

  2. Thermal and Electrical Conductivity of Ge1Sb4Te7 Chalcogenide Alloy

    Science.gov (United States)

    Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

    2017-02-01

    The unique properties of the Ge1Sb4Te7 alloy as a chalcogenide make it a good candidate for application in phase-change random access memory as well as thermoelectric materials. The thermal and electrical conductivity of the Ge1Sb4Te7 alloy play an important role in both applications. This work aims to determine the thermal conductivity and electrical resistivity of the Ge1Sb4Te7 alloy as a function of temperature and to discuss the thermal conduction mechanism. Thermal conductivity and electrical resistivity were measured from room temperature to 778 K using the hot strip method and the four-terminal method, respectively. The thermal conductivity of the Ge1Sb4Te7 alloy shows an interesting temperature dependence: it decreases up to about 600 K, and then increases with increasing temperature. The electrical resistivity shows a monotonic increase with increasing temperature. Through a discussion of the thermal conductivity results together with electrical resistivity results, it is proposed that electronic thermal conductivity dominates the thermal conductivity, while the bipolar diffusion contributes to the increase in the thermal conductivity at higher temperatures. The resonance bonding existing in this chalcogenide alloy accounts for the low lattice thermal conductivity.

  3. Laser processing for thin film chalcogenide photovoltaics: a review and prospectus

    Science.gov (United States)

    Simonds, Brian J.; Meadows, Helene J.; Misra, Sudhajit; Ferekides, Christos; Dale, Phillip J.; Scarpulla, Michael A.

    2015-01-01

    We review prior and on-going works in using laser annealing (LA) techniques in the development of chalcogenide-based [CdTe and Cu(In,Ga)S] solar cells. LA can achieve unique processing regimes as the wavelength and pulse duration can be chosen to selectively heat particular layers of a thin film solar cell or even particular regions within a single layer. Pulsed LA, in particular, can achieve non-steady-state conditions that allow for stoichiometry control by preferential evaporation, which has been utilized in CdTe solar cells to create Ohmic back contacts. Pulsed lasers have also been used with Cu(In,Ga)S to improve device performance by surface-defect annealing as well as bulk deep-defect annealing. Continuous-wave LA shows promise for use as a replacement for furnace annealing as it almost instantaneously supplies heat to the absorbing film without wasting time or energy to bring the much thicker substrate to temperature. Optimizing and utilizing such a technology would allow production lines to increase throughput and thus manufacturing capacity. Lasers have also been used to create potentially low-cost chalcogenide thin films from precursors, which is also reviewed.

  4. Towards efficient solar-to-hydrogen conversion: Fundamentals and recent progress in copper-based chalcogenide photocathodes

    Science.gov (United States)

    Chen, Yubin; Feng, Xiaoyang; Liu, Maochang; Su, Jinzhan; Shen, Shaohua

    2016-09-01

    Photoelectrochemical (PEC) water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, Ga)Se2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

  5. High-Performance, High-Index-Contrast Chalcogenide Glass Photonics on Silicon and Unconventional Non-planar Substrates

    CERN Document Server

    Zou, Yi; Lin, Hongtao; Li, Lan; Moreel, Loise; Zhou, Jie; Du, Qingyang; Ogbuu, Okechukwu; Danto, Sylvain; Musgraves, J David; Richardson, Kathleen; Dobson, Kevin D; Birkmire, Robert; Hu, Juejun

    2013-01-01

    This paper reports a versatile, roll-to-roll and backend compatible technique for the fabrication of high-index-contrast photonic structures on both silicon and plastic substrates. The fabrication technique combines low-temperature chalcogenide glass film deposition and resist-free single-step thermal nanoimprint to process low-loss (1.6 dB/cm), sub-micron single-mode waveguides with a smooth surface finish using simple contact photolithography. Using this approach, the first chalcogenide glass micro-ring resonators are fabricated by thermal nanoimprint. The devices exhibit an ultra-high quality-factor of 400,000 near 1550 nm wavelength, which represents the highest value reported in chalcogenide glass micro-ring resonators. Furthermore, sub-micron nanoimprint of chalcogenide glass films on non-planar plastic substrates is demonstrated, which establishes the method as a facile route for monolithic fabrication of high-index-contrast devices on a wide array of unconventional substrates.

  6. Towards efficient solar-to-hydrogen conversion: Fundamentals and recent progress in copper-based chalcogenide photocathodes

    Directory of Open Access Journals (Sweden)

    Chen Yubin

    2016-09-01

    Full Text Available Photoelectrochemical (PEC water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, GaSe2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

  7. Application of photo-doping phenomenon in amorphous chalcogenide GeS2 film to optical device

    Science.gov (United States)

    Murakami, Yoshihisa; Arai, Katsuya; Wakaki, Moriaki; Shibuya, Takehisa; Shintaku, Toshihiro

    2015-03-01

    Photodoping phenomenon is observed when a double-layer consisting of an amorphous chalcogenide film (As2S3, GeS2, GeSe2 etc.) and a metal (Ag, Cu etc.) film is illuminated by light. The metal diffuses abnormally into the amorphous chalcogenide layer. Amorphous chalcogenide films of GeS2 with an Ag over layer exhibited large increase of refractive index through the abnormal doping of Ag by irradiating the light around the absorption edge of the GeS2 chalcogenide. In this study, we aimed the application of this effect for the fabrication of optical devices and fabricated various micro doped patterns by using a laser beam. Mask less pattering with refractive index modified films are possible by manipulating the scanning of the laser beam. Micro gratings were fabricated using a confocal laser microscope to work as both fabrication and observation system. Waveguides were also fabricated by scanning the laser beam for photodoping. Holographic gratings were fabricated by utilizing the photodoping of the two beam interference pattern, which showed the possibility to produce large scale optical devices or mass production.

  8. Miscellaneous Industrial Mineral Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  9. Synthesis, crystal structure and electrical properties of the tetrahedral quaternary chalcogenides CuM2InTe4 (M=Zn, Cd)

    Science.gov (United States)

    Nolas, George S.; Hassan, M. Shafiq; Dong, Yongkwan; Martin, Joshua

    2016-10-01

    Quaternary chalcogenides form a large class of materials that continue to be of interest for energy-related applications. Certain compositions have recently been identified as possessing good thermoelectric properties however these materials typically have the kesterite structure type with limited variation in composition. In this study we report on the structural, optical and electrical properties of the quaternary chalcogenides CuZn2InTe4 and CuCd2InTe4 which crystallize in the modified zinc-blende crystal structure, and compare their properties with that of CuZn2InSe4. These p-type semiconductors have direct band gaps of about 1 eV resulting in relatively high Seebeck coefficient and resistivity values. This work expands on the research into quaternary chalcogenides with new compositions and structure types in order to further the fundamental investigation of multinary chalcogenides for potential thermoelectrics applications.

  10. Determinants of pathologic mineralization.

    Science.gov (United States)

    Kirsch, Thorsten

    2008-01-01

    Physiologic mineralization is necessary for the formation of skeletal tissues and for their appropriate functions during adulthood. Mineralization has to be controlled and restricted to specific regions. If the mineralization process occurs in regions that normally do not mineralize, there can be severe consequences (pathologic or ectopic mineralization). Recent findings have indicated that physiologic and pathologic mineralization events are initiated by matrix vesicles, membrane-enclosed particles released from the plasma membranes of mineralization-competent cells. The understanding of how these vesicles are released from the plasma membrane and initiate the mineralization process may provide novel therapeutic strategies to prevent pathologic mineralization. In addition, other regulators (activators and inhibitors) of physiologic mineralization have been identified and characterized, and there is evidence that the same factors also contribute to the regulation of pathologic mineralization. Finally, programmed cell death (apoptosis) may be a contributor to physiologic mineralization and if occurring after tissue injury may induce pathologic mineralization and mineralization-related differentiation events in the injured and surrounding areas. This review describes how the understanding of mechanisms and factors regulating physiologic mineralization can be used to develop new therapeutic strategies to prevent pathologic or ectopic mineralization events.

  11. Electron irradiation induced reduction of the permittivity in chalcogenide glass (As2S3) thin film

    KAUST Repository

    San-Román-Alerigi, Damián P.

    2013-01-01

    In this paper, we investigate the effect of electron beam irradiation on the dielectric properties of As 2 S 3 chalcogenide glass. By means of low-loss electron energy loss spectroscopy, we derive the permittivity function, its dispersive relation, and calculate the refractive index and absorption coefficients under the constant permeability approximation. The measured and calculated results show a heretofore unseen phenomenon: a reduction in the permittivity of ? 40 %. Consequently a reduction of the refractive index of 20%, hence, suggests a conspicuous change in the optical properties of the material under irradiation with a 300 keV electron beam. The plausible physical phenomena leading to these observations are discussed in terms of the homopolar and heteropolar bond dynamics under high energy absorption. The reported phenomena, exhibited by As 2 S 3-thin film, can be crucial for the development of photonics integrated circuits using electron beam irradiation method. © 2013 American Institute of Physics.

  12. Modeling of Mid-IR Amplifier Based on an Erbium-Doped Chalcogenide Microsphere

    Directory of Open Access Journals (Sweden)

    P. Bia

    2012-01-01

    Full Text Available An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is designed and optimized. A dedicated 3D numerical model, which exploits the coupled mode theory and the rate equations, is used. The main transitions among the erbium energy levels, the amplified spontaneous emission, and the most important secondary transitions pertaining to the ion-ion interactions have been considered. Both the pump and signal beams are efficiently injected and obtained by a suitable design of the taper angle and the fiber-microsphere gap. Moreover, a good overlapping between the optical signals and the rare-earth-doped region is also obtained. In order to evaluate the amplifier performance in reduced computational time, the doped area is partitioned in sectors. The obtained simulation results highlight that a high-efficiency midinfrared amplification can be obtained by using a quite small microsphere.

  13. Ultrabroadband, Midinfrared Supercontinuum Generation in Dispersion Engineered As2Se3-Based Chalcogenide Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    Rim Cherif

    2013-01-01

    Full Text Available Small core As2Se3-based photonic crystal fibers (PCFs are accurately characterized for compact, high power, ultrabroadband, and coherent supercontinuum generation within few millimeters fiber length. Bandwidths of ~5.3 μm, 5 μm, and 3.2 μm were calculated for hole-to-hole spacings Λ= 3.5 μm, 4.5 μm, and 5.5 μm, respectively. The spectral broadening in the chalcogenide PCF is mainly caused by self-phase modulation and Raman-induced soliton self-frequency shift. The results show that small core As2Se3 PCFs are a promising candidate for mid-IR SCG up to ~8 μm.

  14. Organic phase synthesis of noble metal-zinc chalcogenide core-shell nanostructures.

    Science.gov (United States)

    Kumar, Prashant; Diab, Mahmud; Flomin, Kobi; Rukenstein, Pazit; Mokari, Taleb

    2016-10-15

    Multi-component nanostructures have been attracting tremendous attention due to their ability to form novel materials with unique chemical, optical and physical properties. Development of hybrid nanostructures that are composed of metal-semiconductor components using a simple approach is of interest. Herein, we report a robust and general organic phase synthesis of metal (Au or Ag)-Zinc chalcogenide (ZnS or ZnSe) core-shell nanostructures. This synthetic protocol also enabled the growth of more compositionally complex nanostructures of Au-ZnSxSe1-x alloys and Au-ZnS-ZnSe core-shell-shell. The optical and structural properties of these hybrid nanostructures are also presented.

  15. Atomic Layering, Intermixing and Switching Mechanism in Ge-Sb-Te based Chalcogenide Superlattices

    Science.gov (United States)

    Yu, Xiaoming; Robertson, John

    2016-11-01

    GeSbTe-based chalcogenide superlattice (CSLs) phase-change memories consist of GeSbTe layer blocks separated by van der Waals bonding gaps. Recent high resolution electron microscopy found two types of disorder in CSLs, a chemical disorder within individual layers, and SbTe bilayer stacking faults connecting one block to an adjacent block which allows individual block heights to vary. The disorder requires a generalization of the previous switching models developed for CSL systems. Density functional calculations are used to describe the stability of various types of intra-layer disorder, how the block heights can vary by means of SbTe-based stacking faults and using a vacancy-mediated kink motion, and also to understand the nature of the switching process in more chemically disordered CSLs.

  16. Modeling of switching mechanism in GeSbTe chalcogenide superlattices

    Science.gov (United States)

    Yu, Xiaoming; Robertson, John

    2015-07-01

    We study the switching process in chalcogenide superlattice (CSL) phase-change memory materials by describing the motion of an atomic layer between the low and high resistance states. Two models have been proposed by different groups based on high-resolution electron microscope images. Model 1 proposes a transition from Ferro to Inverted Petrov state. Model 2 proposes a switch between Petrov and Inverted Petrov states. For each case, we note that the main transition is actually a vertical displacement of a Ge layer through a Te layer, followed by a lateral motion of GeTe sublayer to the final, low energy structure. Through calculating energy barriers, the rate-determining step is the displacive transition.

  17. Chalcogenide glass planar MIR couplers for future chip based Bracewell interferometers

    CERN Document Server

    Goldsmith, Harry-Dean Kenchington; Ireland, Michael; Ma, Pan; Tuthill, Peter; Eggleton, Ben; Lawrence, John S; Debbarma, Sukanta; Luther-Davies, Barry; Madden, Stephen J

    2016-01-01

    Photonic integrated circuits are established as the technique of choice for a number of astronomical processing functions due to their compactness, high level of integration, low losses, and stability. Temperature control, mechanical vibration and acoustic noise become controllable for such a device enabling much more complex processing than can realistically be considered with bulk optics. To date the benefits have mainly been at wavelengths around 1550 nm but in the important Mid-Infrared region, standard photonic chips absorb light strongly. Chalcogenide glasses are well known for their transparency to beyond 10000 nm, and the first results from coupler devices intended for use in an interferometric nuller for exoplanetary observation in the Mid-Infrared L band (3800-4200 nm) are presented here showing that suitable performance can be obtained both theoretically and experimentally for the first fabricated devices operating at 4000 nm.

  18. Valence band structure of binary chalcogenide vitreous semiconductors by high-resolution XPS

    Energy Technology Data Exchange (ETDEWEB)

    Kozyukhin, S., E-mail: sergkoz@igic.ras.ru [Russian Academy of Science, Institute of General and Inorganic Chemistry (Russian Federation); Golovchak, R. [Lviv Scientific Research Institute of Materials of SRC ' Carat' (Ukraine); Kovalskiy, A. [Lehigh University, Department of Materials Science and Engineering (United States); Shpotyuk, O. [Lviv Scientific Research Institute of Materials of SRC ' Carat' (Ukraine); Jain, H. [Lehigh University, Department of Materials Science and Engineering (United States)

    2011-04-15

    High-resolution X-ray photoelectron spectroscopy (XPS) is used to study regularities in the formation of valence band electronic structure in binary As{sub x}Se{sub 100-x}, As{sub x}S{sub 100-x}, Ge{sub x}Se{sub 100-x} and Ge{sub x}S{sub 100-x} chalcogenide vitreous semiconductors. It is shown that the highest occupied energetic states in the valence band of these materials are formed by lone pair electrons of chalcogen atoms, which play dominant role in the formation of valence band electronic structure of chalcogen-rich glasses. A well-expressed contribution from chalcogen bonding p electrons and more deep s orbitals are also recorded in the experimental valence band XPS spectra. Compositional dependences of the observed bands are qualitatively analyzed from structural and compositional points of view.

  19. Ultra-large Mode Area Microstructured Core Chalcogenide Fiber Design for Mid-IR Beam Delivery

    CERN Document Server

    Barh, Ajanta; Varshney, R K; Pal, Bishnu P

    2013-01-01

    An all solid large modearea (LMA) chalcogenide based microstructured core optical fiber (MCOF) is designed and proposed for high power handling in the mid IR spectral regime, covering the entire second transparency window of the atmosphere (3 to 5 microns). The core of the proposed specialty fiber is composed of a few rings of high index rods arranged in a pattern of hexagon. Dependence of effective mode area on the pitch and radius of high index rods are studied. Ultra high effective mode area up to 75000 micron square can be achieved over this specific wavelength range while retaining its single mode characteristic. A negligible confinement loss along with a low dispersion slope (near 0.03 ps/km-nm square) and a good beam quality factor (M2 1.17) should make this LMA fiber design attractive for fabrication as a potential candidate suitable for high power, passive applications at the mid IR wavelength regime.

  20. Mid-infrared supercontinuum generation in tapered As2S3 chalcogenide planar waveguide

    Science.gov (United States)

    Zhang, Xiang; Hu, Hongyu; Li, Wenbo; Dutta, Niloy K.

    2016-10-01

    We numerically demonstrate mid-infrared supercontinuum generation in a non-uniformly tapered chalcogenide planar waveguide. This planar rib waveguide of As2S3 glass on MgF2 is 2 cm long with increasing etch depth longitudinally to manage the total dispersion. This waveguide has zero dispersion at two wavelengths. The dispersion profile varies along the propagation distance, leading to continuous modification of the phase-matching condition for dispersive wave emission and enhancement of energy transfer efficiency between solitons and dispersive waves. Numerical simulations are conducted for secant input pulses at a wavelength of 1.55 μm with a width of 50 fs and peak power of 2 kW. Results show this proposed scheme significantly broadens the generated continuum, extending from ~1 to ~7 μm.

  1. Properties of molten Ge chalcogenides an ab initio molecular dynamics study

    CERN Document Server

    Raty, J Y; Bichara, C

    2003-01-01

    In this study, we perform first-principles molecular dynamics simulations of the eutectic alloy Ge sub 1 sub 5 Te sub 8 sub 5 at five different densities and temperatures. We obtain structures in agreement with the available diffraction data and obtain a new view of the molten Ge chalcogenides. We show that the anomalous volume contraction observed in the liquid 30 K above the eutectic temperature corresponds to a significant change of the Ge-Te partial structure factor. The detailed structural analysis shows that volume variations observed upon melting in Ge sub 1 sub 5 Te sub 8 sub 5 , as in liquid GeSe and GeTe, can be explained in terms of the competition between two types of local environment of the germanium atoms. A symmetrical coordination octahedron is entropically favoured at high temperature, while an asymmetrical octahedron resulting from the local manifestation of the Peierls distortion is electronically favoured at lower temperatures.

  2. Simulation of an erbium-doped chalcogenide micro-disk mid-infrared laser source.

    Science.gov (United States)

    Al Tal, Faleh; Dimas, Clara; Hu, Juejun; Agarwal, Anu; Kimerling, Lionel C

    2011-06-20

    The feasibility of mid-infrared (MIR) lasing in erbium-doped gallium lanthanum sulfide (GLS) micro-disks was examined. Lasing condition at 4.5 µm signal using 800 nm pump source was simulated using rate equations, mode propagation and transfer matrix formulation. Cavity quality (Q) factors of 1.48 × 10(4) and 1.53 × 10(6) were assumed at the pump and signal wavelengths, respectively, based on state-of-the-art chalcogenide micro-disk resonator parameters. With an 80 µm disk diameter and an active erbium concentration of 2.8 × 10(20) cm(-3), lasing was shown to be possible with a maximum slope efficiency of 1.26 × 10(-4) and associated pump threshold of 0.5 mW.

  3. Second harmonic generation in nanoscale films of transition metal chalcogenides: Taking into account multibeam interference

    Science.gov (United States)

    Lavrov, S. D.; Kudryavtsev, A. V.; Shestakova, A. P.; Kulyuk, L.; Mishina, E. D.

    2016-05-01

    Second harmonic generation is studied in structures containing nanoscale layers of transition metal chalcogenides that are two-dimensional semiconductors and deposited on a SiO2/Si substrate. The second harmonic generation intensity is calculated with allowance for multibeam interference in layers of dichalcogenide and silicon oxide. The coefficient of reflection from the SiO2-layer-based Fabry-Perot cavity is subsequently calculated for pump wave fields initiating nonlinear polarization at every point of dichalcogenide, which is followed by integration of all second harmonic waves generated by this polarization. Calculated second harmonic intensities are presented as functions of dichalcogenide and silicon oxide layer thicknesses. The dependence of the second harmonic intensity on the MoS2 layer thickness is studied experimentally in the layer of 2-140 nm. A good coincidence of the experimental data and numerical simulation results has been obtained.

  4. Bandgaps of the Chalcogenide Glass Hollow-Core Photonic Crystal Fiber

    Science.gov (United States)

    Li, Shu-Guang; Zhou, Hong-Song; Yin, Guo-Bing

    2011-11-01

    Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method. A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps. For enlarging the bandgap width, an improved GLS HC-PCF is put forward, the normalized frequency kΛ of the improved fiber is from 7.2 to 8.5 in its first bandgap. The improved GLS HC-PCF with pitch of 4.2 μm can transmit the lights with wavelengths ranging from 3.1 μm to 3.7 μm.

  5. Investigation of magnetic phases in parent compounds of iron-chalcogenides via quasiparticle scattering interference

    Science.gov (United States)

    Kamble, Bhaskar; Akbari, Alireza; Eremin, Ilya

    2016-04-01

    We employ a five-orbital tight-binding model to develop the mean-field solution for various possible spin density wave states in the iron-chalcogenides. The quasiparticle interference (QPI) technique is applied to detect signatures of these states due to scatterings arising from non-magnetic impurities. Apart from the experimentally observed double-striped structure with ordering vector (π/2,π/2) , the QPI method is investigated for the extended-stripe as well as the orthogonal double-stripe phase. We discuss QPI as a possible tool to detect and classify various magnetic structures with different electronic structure reconstruction within the framework of the \\text{Fe}1+y\\text{Te} compound.

  6. Si1Sb2Te3 phase change material for chalcogenide random access memory

    Institute of Scientific and Technical Information of China (English)

    Zhang Ting; Song Zhi-Tang; Liu Bo; Liu Wei-Li; Feng Song-Lin; Chen Bomy

    2007-01-01

    This paper investigated phase change Si1Sb2Te3 material for application of chalcogenide random access memory.Current-voltage performance was conducted to determine threshold current of phase change from amorphous phase to polycrystalline phase.The film holds a threshold current about 0.155 mA,which is smaller than the value 0.31 mA of Ge2Sb2Te5 film.Amorphous Si1Sb2Te3 changes to face-centred-cubic structure at~180°C and changes to hexagonal structure at~270°C.Annealing temperature dependent electric resistivity of Si1Sb2Te3 film was studied by four-point probe method.Data retention of the films was characterized as well.

  7. An SMS structure based temperature sensor using a chalcogenide multimode fibre

    Science.gov (United States)

    Wang, Pengfei; Yuan, Libo; Brambilla, Gilberto; Farrell, Gerald

    2016-11-01

    In this work we investigated the fabrication of a singlemode-multimode-singlemode (SMS) fibre structure based on a chalcogenide (As2S3 and AsxS1-x) multimode fibre (MMF) sandwiched between two standard silica singlemode fibres (SMFs) using a commercial fibre fusion splicer. The temperature dependence of this hybrid fibre structure was also investigated. A first proof of concept showed that the hybrid SMS fibre structure has an average experimental temperature sensitivity of 50.63 pm/°C over a temperature range of 20 °C 100°C at wavelengths around 1.55 μm. The measured results show a general agreement with numerical simulations based on a guided-mode propagation analysis method. Our result provides a potential platform for the development of compact, high-optical-quality and robust sensing devices operating at the mid-infrared wavelength range.

  8. Dynamics of the current filament formation and its steady-state characteristics in chalcogenide based PCM

    Science.gov (United States)

    Bogoslovskiy, Nikita; Tsendin, Konstantin

    2017-03-01

    In the phase-change memory (PCM) crystallization occurs in the high-current filament which forms during switching to the conductive state. In the present paper we conduct a numerical modeling of the current filament formation dynamics in thin chalcogenide films using an electronic-thermal model based on negative-U centers tunnel ionization and Joule heating. The key role of inhomogeneities in the filament formation process is shown. Steady-state filament parameters were obtained from the analysis of the stationary heat conduction equation. The filament formation dynamics and the steady-state filament radius and temperature could be controlled by material parameters and contact resistance. Consequently it is possible to control the size of the region wherein crystallization occurs. A good agreement with numerous experimental data leads to the conclusion that thermal effects play a significant role in CGS conduction and high-current filament formation while switching.

  9. Thermal and Dielectric Studies On Ge10se69tl21 Chalcogenide Glass

    Directory of Open Access Journals (Sweden)

    B.J. Madhu

    2011-01-01

    Full Text Available Bulk Ge10Se69Tl21 chalcogenide glass is prepared by melt quenching technique. Thermal analysis of bulk Ge10Se69Tl21 glass has been undertaken using temperature modulated Alternating Differential Scanning Calorimetry (ADSC. The Ge10Se69Tl21 glass is found to exhibit single glass transition temperature (Tg and double stage crystallization reactions (Tc1 & Tc2. The dependence of dielectric properties such as dielectric loss tangent (tanδ, dielectric constant (ε’ and dielectric loss factor (ε’’ on the frequency has been studied at the room temperature in the frequency range 10 kHz to 5 MHz. The dielectric parameters tanδ, ε’and ε’’ are found to decrease with the increase in the frequency. Further, resistance of the Ge10Se69Tl21 sample is also found to decrease with the increase in the frequency.

  10. New materials for optoelectronic devices: Growth and characterization of indium and gallium chalcogenide layer compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, A.M.; Micocci, G.; Rizzo, A.

    1983-09-01

    The main characteristics and the possible applications of some new materials for optoelectronic devices are analyzed. For this purpose, the most widely used growth methods for obtaining good quality single crystals of indium and gallium chalcogenide layered compounds are described together with the best results obtained by us in the growth of GaS, GaSe, GaTe and InSe. The structural characteristics of these compounds, as inferred by electron and X-ray diffraction are reported. The electrical and optical properties of the various materials are related to the growth methods and are analyzed taking into account the trapping centers present in the energy gaps. The parameters of these centers are reported for all the analyzed layered compounds as determined by different electric and photoelectric techniques.

  11. Power-efficient production of photon pairs in a tapered chalcogenide microwire

    Energy Technology Data Exchange (ETDEWEB)

    Meyer-Scott, Evan, E-mail: emeyersc@uwaterloo.ca; Dot, Audrey [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Ahmad, Raja; Li, Lizhu; Rochette, Martin [Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montréal, Québec H3A 2A7 (Canada); Jennewein, Thomas [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Quantum Information Science Program, Canadian Institute for Advanced Research, 180 Dundas Street West, Suite 1400, Toronto, Ontario M5G 1Z8 (Canada)

    2015-02-23

    Using tapered fibers of As{sub 2}Se{sub 3} chalcogenide glass, we produce photon pairs at telecommunication wavelengths with low pump powers. We found maximum coincidences-to-accidentals ratios of 2.13 ± 0.07 for degenerate pumping with 3.2 μW average power, and 1.33 ± 0.03 for non-degenerate pumping with 1.0 μW and 1.5 μW average power of the two pumps. Our results show that the ultrahigh nonlinearity in these microwires could allow single-photon pumping to produce photon pairs, enabling the production of large entangled states, heralding of single photons after lossy transmission, and photonic quantum information processing with nonlinear optics.

  12. Effect of CaF2 on Process of Mineral Formation and Hydration of Calcium Strontium Sulphoaluminate Cement%CaF2对硫铝酸锶钙水泥矿物形成及水化过程的影响

    Institute of Scientific and Technical Information of China (English)

    谭文杰; 艾红梅; 常钧; 鲁统卫; 王勇威

    2012-01-01

    The compressive strength of calcium strontium sulphoaluminate cement with CaF2 added was tested. The influence of CaF2 on process of mineral formation and hydration of calcium strontium sulphoaluminate cement were studied by thermal analysis(DTA-TG), X-ray diffractionCXRD) and scanning electron microscopy(SEM). The results show that compressive strength of calcium strontium sulphoaluminate cement with 0. 2% ( by mass) of CaF2 added is optimal, the compressive strength for 3.28 d is 65. 0, 86.2 MPa respectively, CaF2 accelerates decomposition of CaCO3 and formation of C1.50 Sr2.50 A3S during sintering of clinker. Due to CaF2 , hydration rate of cement is speeded up and CAH10 changes to C3 AH6.%测试了掺CaF2硫铝酸锶钙水泥的抗压强度.通过热分析、X射线衍射分析和扫描电子显微镜观察,研究了CaF2对硫铝酸锶钙水泥熟料矿物形成和水化过程的影响.结果表明,当CaF2掺量为0.2%(质量分数)时,硫铝酸锶钙水泥抗压强度最高,3,28 d抗压强度分别达到65.0,86.2 MPa.在水泥煅烧过程中,CaF2能加速CaCO3的分解及C1.50Sr2.50A3S矿物的形成.此外,CaF2可以加快硫铝酸锶钙水泥的水化速率并促使水化产物CAH10转化为C3 AH6.

  13. Dy{sup 3+}-doped Ga–Sb–S chalcogenide glasses for mid-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Mingjie [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Yang, Anping, E-mail: apyang@jsnu.edu.cn [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Peng, Yuefeng [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Zhang, Bin; Ren, He; Guo, Wei; Yang, Yan; Zhai, Chengcheng; Wang, Yuwei; Yang, Zhiyong; Tang, Dingyuan [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China)

    2015-10-15

    Highlights: • Novel Ga–Sb–S chalcogenide glasses doped with Dy{sup 3+} ions were synthesized. • The glasses show good thermal stability and excellent infrared transparency. • The glasses show low phonon energy and intense mid-infrared emissions. • The mid-infrared emissions have high quantum efficiency. • The mid-infrared emissions have large stimulated emission cross sections. - Abstract: Novel Ga–Sb–S chalcogenide glasses doped with different amount of Dy{sup 3+} ions were prepared. Their thermal stability, optical properties, and mid-infrared (MIR) emission properties were investigated. The glasses show good thermal stability, excellent infrared transparency, very low phonon energy (∼306 cm{sup −1}), and intense emissions centered at 2.95, 3.59, 4.17 and 4.40 μm. Three Judd–Ofelt intensity parameters (Ω{sub 2} = 8.51 × 10{sup −20} cm{sup 2}, Ω{sub 4} = 2.09 × 10{sup −20} cm{sup 2}, and Ω{sub 6} = 1.60 × 10{sup −20} cm{sup 2}) are obtained, and the related radiative transition properties are evaluated. The high quantum efficiencies and large stimulated emission cross sections of the MIR emissions (88.10% and 1.11 × 10{sup −20} cm{sup 2} for 2.95 μm emission, 75.90% and 0.38 × 10{sup −20} cm{sup 2} for 4.40 μm emission, respectively) in the Dy{sup 3+}-doped Ga–Sb–S glasses make them promising gain materials for the MIR lasers.

  14. Hubbard interactions in iron-based pnictides and chalcogenides: Slater parametrization, screening channels, and frequency dependence

    Science.gov (United States)

    van Roekeghem, Ambroise; Vaugier, Loïg; Jiang, Hong; Biermann, Silke

    2016-09-01

    We calculate the strength of the frequency-dependent on-site electronic interactions in the iron pnictides LaFeAsO, BaFe2As2 , BaRu2As2 , and LiFeAs and the chalcogenide FeSe from first principles within the constrained random phase approximation. We discuss the accuracy of an atomiclike parametrization of the two-index density-density interaction matrices based on the calculation of an optimal set of three independent Slater integrals, assuming that the angular part of the Fe d localized orbitals can be described within spherical harmonics as for isolated Fe atoms. We show that its quality depends on the ligand-metal bonding character rather than on the dimensionality of the lattice: it is excellent for ionic-like Fe-Se (FeSe) chalcogenides and a more severe approximation for more covalent Fe-As (LaFeAsO, BaFe2As2 ) pnictides. We furthermore analyze the relative importance of different screening channels, with similar conclusions for the different pnictides but a somewhat different picture for the benchmark oxide SrVO3: the ligand channel does not appear to be dominant in the pnictides, while oxygen screening is the most important process in the oxide. Finally, we analyze the frequency dependence of the interaction. In contrast to simple oxides, in iron pnictides its functional form cannot be simply modeled by a single plasmon, and the actual density of modes enters the construction of an effective Hamiltonian determining the low-energy properties.

  15. Mid-infrared supercontinuum generation spanning more than 11 μm in a chalcogenide step-index fiber

    DEFF Research Database (Denmark)

    Petersen, Christian Rosenberg; Møller, Uffe Visbech; Kubat, Irnis;

    2015-01-01

    Supercontinuum generation covering an ultra-broad spectrum from 1.5-11.7μm and 1.4-13.3μm is experimentally demonstrated by pumping an 85mm chalcogenide step-index fiber with 100fs pulses at a wavelength of 4.5μm and 6.3μm, respectively.......Supercontinuum generation covering an ultra-broad spectrum from 1.5-11.7μm and 1.4-13.3μm is experimentally demonstrated by pumping an 85mm chalcogenide step-index fiber with 100fs pulses at a wavelength of 4.5μm and 6.3μm, respectively....

  16. Fabrication of SiGeSb heating electrodes and their application for four-terminal chalcogenide programmable switches

    Science.gov (United States)

    Park, Young Sam; Lee, Seung-Yun

    2015-03-01

    This paper reports on sputter-deposited SiGeSb thin films and their application for four-terminal chalcogenide switch devices. The microstructures and electrical properties of the SiGeSb films were highly dependent on antimony concentration and annealing temperature. Microstructural changes such as surface roughening and formation of antimony grains were observed only for the Sb-rich SiGeSb films after annealing at 400 °C and higher. The sheet resistance of the SiGeSb films containing a small amount of antimony changed sporadically with annealing temperature because of a trade-off between activation and surface depletion of antimony. The resistance of the SiGeSb heating electrodes was varied by changing sputtering power for the antimony target and by changing the annealing temperature. Four-terminal chalcogenide switch devices were fabricated with SiGeSb heating electrodes of varying resistance. It was found that the switching voltage of the fabricated switch device was proportional to the resistance of the SiGeSb heating electrode. This indicates that the SiGeSb films with tunable sheet resistance are of great importance in fabricating chalcogenide switch devices and the optimization of the resistance of the SiGeSb film is essential to ensure proper switch operation.

  17. A Self-Templating Scheme for the Synthesis of Nanostructured Transition Metal Chalcogenide Electrodes for Capacitive Energy Storage

    KAUST Repository

    Xia, Chuan

    2015-06-11

    Due to their unique structural features including well-defined interior voids, low density, low coefficients of thermal expansion, large surface area and surface permeability, hollow micro/nanostructured transition metal sulfides with high conductivity have been investigated as new class of electrode materials for pseudocapacitor applications. Herein, we report a novel self-templating strategy to fabricate well-defined single and double-shell NiCo2S4 hollow spheres, as a promising electrode material for pseudocapacitors. The surfaces of the NiCo2S4 hollow spheres consist of self-assembled 2D mesoporous nanosheets. This unique morphology results in a high specific capacitance (1257 F g-1 at 2 A g-1), remarkable rate performance (76.4% retention of initial capacitance from 2 A g-1 to 60 A g-1) and exceptional reversibility with a cycling efficiency of 93.8% and 87% after 10,000 and 20,000 cycles, respectively, at a high current density of 10 A g-1. The cycling stability of our ternary chalcogenides is comparable to carbonaceous electrode materials, but with much higher specific capacitance (higher than any previously reported ternary chalcogenide), suggesting that these unique chalcogenide structures have potential application in next-generation commercial pseudocapacitors.

  18. Linear and nonlinear optical properties of new Se-based quaternary Se-Sn-(Bi,Te) chalcogenide thin films

    Science.gov (United States)

    Yadav, Preeti; Sharma, Ambika

    2015-02-01

    We are reporting the linear and nonlinear optical properties of Se-based quaternary chalcogenide Se-Sn-(Bi,Te) thin films. Thin films of bulk chalcogenide glasses, prepared by melt quenching method are deposited on glass substrate using thermal evaporation technique. The optical behavior of studied chalcogenide glass systems is investigated using transmission spectra in the spectral range of 400-2500 nm. The glasses exhibit considerable optical nonlinearities which are estimated using linear optical parameters. Linear refractive index has been calculated using well-known Swanepoel method. Wemple-DiDomenico (WDD) parameters are also reported for the investigated glasses. Optical band gap is determined using Tauc extrapolation method and is observed to increase with Sn content. The formulation proposed by Fournier and Snitzer is used to determine the nonlinear behavior of the refractive index. It is observed that n2 increases linearly with increasing n. The values of n2 are compared with pure silica and the results are 100-600 orders higher. The third-order susceptibility χ(3) is also reported in this paper. Two-photon absorption coefficient β2 is determined using optical band gap data. A strong dependence of β2 and n2 is observed on normalized photon energy (?) for a fixed excitation wavelength (1064 nm).

  19. Multilayer systems of alternating chalcogenide As Se and polymer thin films prepared using thermal evaporation and spin-coating techniques

    Science.gov (United States)

    Kohoutek, T.; Wagner, T.; Orava, J.; Krbal, M.; Ilavsky, J.; Vesely, D.; Frumar, M.

    2007-05-01

    We describe preparation and characterization of multilayer planar systems based on alternating chalcogenide As Se and polymer polyamide-imide (PAI) or polyvinyl-butyral (PVB) thin films. We deposited films of thermally evaporated As33Se67 chalcogenide glass periodically alternating with PAI or PVB films. Fifteen layers of As Se+PAI system and 17 layers of As Se+PVB system were deposited. The film thicknesses were approximately 100 nm for all of the film types. Polymer film thicknesses were calculated from profilometric measurements performed by an atomic force microscopy. Optical properties of prepared multilayers and also As Se, PAI and PVB single layers were established using UV vis NIR and ellipsometric spectroscopies. Both, As Se+PAI and As Se+PVB multilayer systems, exhibited the reflection (stop) bands centered near 830 nm. The bandwidth of reflection band of As Se+PAI multilayer was 90 nm while bandwidth of As Se+PVB system increased to 150 nm because PVB films had about 0.2 lower refractive index. A new possibility for the application of chalcogenide thin films appeared as high refractive index materials suitable for fabrication of optical elements (reflectors) for near-infrared region. Changing the films composition and thickness, multilayer systems with tailored position of stop band could be designed and prepared.

  20. Mineral Resources Data System

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Mineral resource occurrence data covering the world, most thoroughly within the U.S. This database contains the records previously provided in the Mineral Resource...

  1. Mineral Supply Challenges

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Faced with shortcomings in its mineral supply, it’s imperative for China to balance its desire for reserves with its current economic needs Mineral resources are the corner- stone of materials needed for China’s national economic and social development.The country even counts on its mineral resources to satisfy 90 percent of its energy demands and over 95

  2. Investigations into the Structure and Dynamics of Chalcogenide Glasses using High-Resolution Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Kaseman, Derrick Charles

    Chalcogenide glasses constitute an important class of materials that are sulfides, selenides or tellurides of group IV and/or V elements, namely Ge, As, P and Si with minor concentrations of other elements such as Ga, Sb, In. Because of their infrared transparency that can be tuned by changing chemistry and can be actively altered by exposure to band gap irradiation, chalcogenide glasses find use in passive and active optical devices for applications in the areas of photonics, remote sensing and memory technology. Therefore, it is important to establish predictive models of structure-property relationships for these materials for optimization of their physical properties for various applications. Structural elucidation of chalcogenide glasses is experimentally challenging and in order to make predictive structural models, structural units at both short and intermediate -range length scales must be identified and quantified. Nuclear Magnetic Resonance (NMR) spectroscopy is an element-specific structural probe that is uniquely suited for this task, but resolution and sensitivity issues have severely limited the applications of such techniques in the past. The recent development of multi-dimensional solid-state NMR techniques, such as Phase Adjusted Spinning Sidebands (PASS) and Magic Angle Turning (MAT) can potentially alleviate such issues. In this study novel two-dimensional, high-resolution 77Se and 125Te MATPASS NMR spectroscopic techniques are utilized to elucidate quantitatively the compositional evolution of the short- and intermediate- range atomic structure in three binary chalcogenide glass-forming systems, namely: GexSe100-x, AsxSe100-x , and AsxTe100-x. The spectroscopic results provide unambiguous site speciation and quantification for short- and intermediate-range structural motifs present in these glasses. In turn, for all systems, robust structural models and the corresponding structure-property relationships are successfully established as a function

  3. Nanoscale structure and atomic disorder in the iron-based chalcogenides.

    Science.gov (United States)

    Saini, Naurang Lal

    2013-02-01

    The multiband iron-based superconductors have layered structure with a phase diagram characterized by a complex interplay of charge, spin and lattice excitations, with nanoscale atomic structure playing a key role in their fundamental electronic properties. In this paper, we briefly review nanoscale structure and atomic disorder in iron-based chalcogenide superconductors. We focus on the Fe(Se,S)1-x Te x (11-type) and K0.8Fe1.6Se2 (122-type) systems, discussing their local structure obtained by extended x-ray absorption fine structure. Local structure studies on the Fe(Se,S)1-x Te x system reveal clear nanoscale phase separation characterized by coexisting components of different atomic configurations, similar to the case of random alloys. In fact, the Fe-Se/S and Fe-Te distances in the ternary Fe(Se,S)1-x Te x are found to be closer to the respective distances in the binary FeSe/FeS and FeTe systems, showing significant divergence of the local structure from the average one. The observed features are characteristic of ternary random alloys, indicating breaking of the local symmetry in these materials. On the other hand, K0.8Fe1.6Se2 is known for phase separation in an iron-vacancy ordered phase and an in-plane compressed lattice phase. The local structure of these 122-type chalcogenides shows that this system is characterized by a large local disorder. Indeed, the experiments suggest a nanoscale glassy phase in K0.8Fe1.6Se2, with the superconductivity being similar to the granular materials. While the 11-type structure has no spacer layer, the 122-type structure contains intercalated atoms unlike the 1111-type REFeAsO (RE = rare earth) oxypnictides, having well-defined REO spacer layers. It is clear that the interlayer atomic correlations in these iron-based superconducting structures play an important role in structural stability as well as superconductivity and magnetism.

  4. Bandgaps of the Chalcogenide Glass Hollow-Core Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    LI Shu-Guang; ZHOU Hong-Song; YIN Guo-Bing

    2011-01-01

    Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method. A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps. For enlarging the bandgap width, an improved GLS HC-PCF is put forward, the normalized frequency kA of the improved fiber is from 7.2 to 8.5 in its first bandgap. The improved GLS HC-PCF with pitch of 4.2μm can transmit the lights with wavelengths ranging from 3.1μm to 3.7μm.%Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method.A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps.For enlarging the bandgap width,an improved GLS HC-PCF is put forward,the normalized frequency κA of the improved fiber is from 7.2 to 8.5 in its first bandgap.The improved GLS HC-PCF with pitch of 4.2μm can transmit the lights with wavelengths ranging from 3.1 μm to 3.7 μm.Photonic crystal fibers (PCFs) can be classified into total internal reflection PCFs and photonic bandgap (PBG) PCFs[1] Solid core PCFs are one kind of the total internal reflection PCFs;hollow-core PCFs (HC-PCFs) are a kind of typical PBG fibers.The conception of HC-PCFs was first proposed by Russel in 1991.[2] Later,it was theoretically demonstrated by Birks et al.[3] in 1995.A bandgap photonic crystal fiber was mde by Knight et al.[4] for the first time in 1998.On the basis of these works,the first HC-PCF was designed and made by Cregan et al.[5] in 1999.

  5. Growth and Characterization of Multisegment Chalcogenide Alloy Nanostructures for Photonic Applications in a Wide Spectral Range

    Science.gov (United States)

    Turkdogan, Sunay

    In this dissertation, I described my research on the growth and characterization of various nanostructures, such as nanowires, nanobelts and nanosheets, of different semiconductors in a Chemical Vapor Deposition (CVD) system. In the first part of my research, I selected chalcogenides (such as CdS and CdSe) for a comprehensive study in growing two-segment axial nanowires and radial nanobelts/sheets using the ternary CdSxSe1-x alloys. I demonstrated simultaneous red (from CdSe-rich) and green (from CdS-rich) light emission from a single monolithic heterostructure with a maximum wavelength separation of 160 nm. I also demonstrated the first simultaneous two-color lasing from a single nanosheet heterostructure with a wavelength separation of 91 nm under sufficiently strong pumping power. In the second part, I considered several combinations of source materials with different growth methods in order to extend the spectral coverage of previously demonstrated structures towards shorter wavelengths to achieve full-color emissions. I achieved this with the growth of multisegment heterostructure nanosheets (MSHNs), using ZnS and CdSe chalcogenides, via our novel growth method. By utilizing this method, I demonstrated the first growth of ZnCdSSe MSHNs with an overall lattice mismatch of 6.6%, emitting red, green and blue light simultaneously, in a single furnace run using a simple CVD system. The key to this growth method is the dual ion exchange process which converts nanosheets rich in CdSe to nanosheets rich in ZnS, demonstrated for the first time in this work. Tri-chromatic white light emission with different correlated color temperature values was achieved under different growth conditions. We demonstrated multicolor (191 nm total wavelength separation) laser from a single monolithic semiconductor nanostructure for the first time. Due to the difficulties associated with growing semiconductor materials of differing composition on a given substrate using traditional planar

  6. Influence of the coordination number Z on the micro-Raman spectra of ternary chalcogenide glasses

    Science.gov (United States)

    Iovu, M. S.; Iaseniuc, O. V.; Dinescu, D.; Enachescu, M.

    2016-12-01

    Chalcogenide glasses are attractive materials due to its application in photonics and optoelectronics. Chalcogenide glasses GexAsxSe1-2x (average coordination number Z=2.15÷2.90) and (As4S3Se3)1-xSnx (average coordination number Z=2.4÷2.56), which contain elements of IV group of the Periodic Table, such as Ge and Sn are important for a wide range of technical applications, such as infrared optical elements, acousto-optic and alloptical switching devices, holographic recording media, diffractive optics, photonic crystals, etc. [1, 2]. Raman spectroscopy is an efficient method for obtaining information on the local structure of the disordered material, especially when the composition is varied. In this paper are reported the Micro-Raman spectra of GexAsxSe1-2x and (As4S3Se3)1-xSnx bulk glasses and amorphous thin films. The Micro-Raman spectra of bulk glasses and thermally deposited amorphous (As4S3Se3)1-xSnx thin films consist of two broad bands located at around ν=236 cm-1 and ν=345 cm-1, which corresponds to the symmetric stretching vibration modes of AsSe3/2 and AsS3/2 pyramids, respectively. Tin impurities didn't change the shape of Micro-Raman spectra, but shift the both bands to low frequency region. The Micro-Raman spectra of bulk glasses and thermally deposited amorphous (GexAsxSe1-2x thin films consist of one main vibration band located at around ν=246 cm-1 for lower concentration of Ge and As, and is attributed to (AsSe1/2)3 pyramidal units. With increasing of Ge and As concentrations this band shifts to lower frequency region up to ν=236 cm-1 for x=0.30. The vibration band situated around ν=205 cm-1 is attributed to Ge(Se1/2)4 tetrahedral units and increase in the intensity with increasing of Ge and As concentrations. Some shoulders in high frequency regions at ν=365-390 cm-1 and ν=500-530 cm-1, caused by the presence of As-Se bands and Se-Se chains also was observed.

  7. Chelated minerals for poultry

    Directory of Open Access Journals (Sweden)

    SL Vieira

    2008-06-01

    Full Text Available Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

  8. Design and growth of novel compounds for radiation sensors: multinary chalcogenides

    Science.gov (United States)

    Singh, N. B.; Su, Ching-Hua; Nagaradona, Teja; Arnold, Brad; Choa, Fow-Sen

    2016-05-01

    Increasing threats of radiological weapons have revitalized the researches for low cost large volume γ-ray and neutron ray sensors In the past few years we have designed and grown ternary and quaternary lead and thallium chalcogenides and lead selenoiodides for detectors to meet these challenges. These materials are congruent, can be tailored to enhance the parameters required for radiation sensors. In addition, this class of compounds can be grown by Bridgman method which promises for large volume productions. We have single crystals of several compounds from the melt including Tl3AsSe3, Tl3AsSe3-xSx, TlGaSe2, AgGaGe3Se8, AgxLi1-xAgGaGe3Se8 and PbTlI5-x Sex compounds. Experimental studies indicate that these have very low absorption coefficient, low defect density and can be fabricated in any shape and sizes. These crystals do not require post growth annealing and do not show any second phase precipitates when processed for electrode bonding and other fabrication steps. In this paper we report purification, growth and fabrication of large Tl3AsSe3 (TAS) crystals. We observed that TAS crystals grown by using further purification of as supplied high purity source materials followed by directionally solidified charge showed higher resistivity than previously reported values. TAS also showed constant value as the function of voltage.

  9. Deposition of metal chalcogenide thin films by successive ionic layer adsorption and reaction (SILAR) method

    Indian Academy of Sciences (India)

    H M Pathan; C D Lokhande

    2004-04-01

    During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc. In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.

  10. Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Wen Jinsheng; Birgeneau, R J [Physics Department, University of California, Berkeley, CA 94720 (United States); Xu Guangyong; Gu Genda; Tranquada, J M, E-mail: jinshengwen@berkeley.edu, E-mail: jtran@bnl.gov [Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-12-15

    In this review, we present a summary of results on single crystal growth of two types of iron-chalcogenide superconductors, Fe{sub 1+y}Te{sub 1-x}Se{sub x} (11), and A{sub x}Fe{sub 2-y}Se{sub 2} (A = K, Rb, Cs, Tl, Tl/K, Tl/Rb), using Bridgman, zone-melting, vapor self-transport and flux techniques. The superconducting and magnetic properties (the latter gained mainly from neutron scattering measurements) of these materials are reviewed to demonstrate the connection between magnetism and superconductivity. It will be shown that for the 11 system, while static magnetic order around the reciprocal lattice position (0.5, 0) competes with superconductivity, spin excitations centered around (0.5, 0.5) are closely coupled to the materials' superconductivity; this is made evident by the strong correlation between the spectral weight around (0.5, 0.5) and the superconducting volume fraction. The observation of a spin resonance below the superconducting temperature, T{sub c}, and the magnetic-field dependence of the resonance emphasize the close interplay between spin excitations and superconductivity, similar to cuprate superconductors. In A{sub x}Fe{sub 2-y}Se{sub 2}, superconductivity with T{sub c} {approx} 30 K borders an antiferromagnetic insulating phase; this is closer to the behavior observed in the cuprates but differs from that in other iron-based superconductors.

  11. Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations

    Science.gov (United States)

    Wen, Jinsheng; Xu, Guangyong; Gu, Genda; Tranquada, J. M.; Birgeneau, R. J.

    2011-12-01

    In this review, we present a summary of results on single crystal growth of two types of iron-chalcogenide superconductors, Fe1+yTe1-xSex (11), and AxFe2-ySe2 (A = K, Rb, Cs, Tl, Tl/K, Tl/Rb), using Bridgman, zone-melting, vapor self-transport and flux techniques. The superconducting and magnetic properties (the latter gained mainly from neutron scattering measurements) of these materials are reviewed to demonstrate the connection between magnetism and superconductivity. It will be shown that for the 11 system, while static magnetic order around the reciprocal lattice position (0.5, 0) competes with superconductivity, spin excitations centered around (0.5, 0.5) are closely coupled to the materials' superconductivity; this is made evident by the strong correlation between the spectral weight around (0.5, 0.5) and the superconducting volume fraction. The observation of a spin resonance below the superconducting temperature, Tc, and the magnetic-field dependence of the resonance emphasize the close interplay between spin excitations and superconductivity, similar to cuprate superconductors. In AxFe2-ySe2, superconductivity with Tc ~ 30 K borders an antiferromagnetic insulating phase; this is closer to the behavior observed in the cuprates but differs from that in other iron-based superconductors.

  12. Size-controlled synthesis of chalcogen and chalcogenide nanoparticles using protic ionic liquids with imidazolium cation

    Energy Technology Data Exchange (ETDEWEB)

    Meenatchi, Boominathan [Cauvery College for Women, Tamilnadu (India); Renuga, Velayutham [National College, Tamilnadu (India); Manikandan, Ayyar [Bharath Institute of Higher Education and Research, Bharath University, Tamilnadu (India)

    2016-03-15

    Green synthesis of selenium (chalcogen) nanoparticles (SeNPs) has been successfully attained by simple wet chemical method that involves the reaction of six different protic ionic liquids with imidazolium cations and sodium hydrogen selenide (NaHSe) in the presence of poly ethylene glycol-600 (PEG-600) as an additional stabilizer. The obtained SeNPs were characterized using UV spectral (UV), Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM) with energy dispersive X-ray (EDX) and high resolution transmission electron microscope (TEM) analysis. The results illustrate that the synthesized SeNPs are spherical in shape with size ranging 19-24 nm and possess good optical property with greater band gap energy, high thermal stability up to 330 .deg. C, low melting point of 218-220 .deg. C comparing to precursor selenium. Using the synthesized SeNPs, two chalcogenides such as ZnSe and CdSe semiconductor nanoparticles were synthesized and characterized using XRD, SEM with EDX and TEM analysis. The fabricated CdSe and ZnSe nanoparticles appeared like pebble and cluster structure with particle size of 29.97 nm and 22.73 nm respectively.

  13. Large and Ultrafast Third-Order Nonlinear Optical Properties of Ge-S Based Chalcogenide Glasses

    Institute of Scientific and Technical Information of China (English)

    CHU Sai-Sai; WANG Shu-Feng; TAO Hai-Zheng; WANG Zhen-Wei; YANG Hong; LIN Chang-Gui; GONG Qi-Huang; ZHAO Xiu-Jian

    2007-01-01

    We report ultrafast third-order nonlinear optical (NLO) properties of several chalcogenide glasses GeSx (x = 1.8,2.0, 2.5) measured by femtosecond time-resolved optical Kerr gate technique at 820nm. The third-order nonlinear susceptibility of GeS1.8 glass is determined to be as large as 1.41 × 10-12 esu, which is the maximum value of the third order nonlinear susceptibility X(3) for the three compositions investigated. The symmetric Gauss profiles of optical Kerr signals reveal the nature of ultrafast nonlinear response of these samples, which are originated from the ultrafast polarization of the electron clouds. By detailed microstructural analysis of these glasses based on the chain-crossing model (CCM) and the random-covalent-network model (RCNM), it can be concluded that X(3) value of GeSx glasses can be enhanced greatly by S-S covalent bonds or S3Ge-GeS3 ethane-like units.

  14. Infrared waveguide fabrications with an E-beam evaporated chalcogenide glass film

    KAUST Repository

    Yang, Xiaoming

    2014-12-12

    Chalcogenide glasses have a variety of unique optical properties due to the intrinsic structural flexibility and bonds metastability. They are desirable materials for many applications, such as infrared communication sensors, holographic grating, optical imaging, and ultrafast nonlinear optic devices. Here, we introduce a novel electron-beam evaporation process to deposit the good quality arsenic trisulfide (As2S3) films and then the As2S3 films were used to fabricate the As2S3 waveguides with three approaches. The first method is photoresist lift-off. Because of the restriction of thermal budget of photoresist, the As2S3 film must be deposited at the room temperature. The second one is the silicon dioxide lift-off process on sapphire substrates, in which the As2S3 film could be evaporated at a high temperature (>180 °C) for better film quality. The third one is the plasma etching process with a metal protective thin layer in the pattern development process.

  15. Ultra broadband flat dispersion tailoring on reversed-rib chalcogenide glass waveguide

    Science.gov (United States)

    Zhai, Yanfen; Qi, Renduo; Yuan, Chenzhi; Zhang, Wei; Huang, Yidong

    2016-11-01

    In this paper, we introduce a horizontal slot in the reversed-rib chalcogenide glass waveguide to tailor its dispersion characteristics. The waveguide exhibits a flat and low dispersion over a wavelength range of 1080 nm, in which the dispersion fluctuates between -10.6 ps·nm-1·km-1 and +11.14 ps·nm-1·km-1. The dispersion tailoring effect is due to the mode field transfer from the reversed-rib waveguide to the slot with the increase of wavelength, which results in the extension of the low dispersion band. Moreover, the nonlinear coefficient and the phase-matching condition of the four-wave mixing process in this waveguide are studied, showing that the waveguide has great potential in nonlinear optical applications over a wide wavelength range. Project supported by the National Basic Research Program of China (Grant Nos. 2013CB328700 and 2011CBA00303) and the National Natural Science Foundation of China (Grant Nos. 61575102 and 61321004).

  16. Hybrid metal-organic chalcogenide nanowires with electrically conductive inorganic core through diamondoid-directed assembly

    Science.gov (United States)

    Yan, Hao; Hohman, J. Nathan; Li, Fei Hua; Jia, Chunjing; Solis-Ibarra, Diego; Wu, Bin; Dahl, Jeremy E. P.; Carlson, Robert M. K.; Tkachenko, Boryslav A.; Fokin, Andrey A.; Schreiner, Peter R.; Vailionis, Arturas; Kim, Taeho Roy; Devereaux, Thomas P.; Shen, Zhi-Xun; Melosh, Nicholas A.

    2016-12-01

    Controlling inorganic structure and dimensionality through structure-directing agents is a versatile approach for new materials synthesis that has been used extensively for metal-organic frameworks and coordination polymers. However, the lack of `solid’ inorganic cores requires charge transport through single-atom chains and/or organic groups, limiting their electronic properties. Here, we report that strongly interacting diamondoid structure-directing agents guide the growth of hybrid metal-organic chalcogenide nanowires with solid inorganic cores having three-atom cross-sections, representing the smallest possible nanowires. The strong van der Waals attraction between diamondoids overcomes steric repulsion leading to a cis configuration at the active growth front, enabling face-on addition of precursors for nanowire elongation. These nanowires have band-like electronic properties, low effective carrier masses and three orders-of-magnitude conductivity modulation by hole doping. This discovery highlights a previously unexplored regime of structure-directing agents compared with traditional surfactant, block copolymer or metal-organic framework linkers.

  17. Two-dimensional topological insulators in group-11 chalcogenide compounds: M2Te (M =Cu ,Ag )

    Science.gov (United States)

    Ma, Yandong; Kou, Liangzhi; Dai, Ying; Heine, Thomas

    2016-06-01

    Two-dimensional (2D) topological insulators (TIs) are recently recognized states of quantum matter that are highly interesting for lower-power-consuming electronic devices owing to their nondissipative transport properties protected from backscattering. So far, only few 2D TIs, suffering from small bulk band gap (TIs in group-11 chalcogenide 2D crystals, M2Te (M =Cu ,Ag ) . The nontrivial topological states in C u2Te and A g2Te 2D crystals, identified by topological invariant and edge state calculations, exhibit sizeable bulk gaps of 78 and 150 meV, respectively, suggesting that they are candidates for room-temperature applications. Moreover, strain engineering leads to effective control of the nontrivial gaps of C u2Te and A g2Te , and a topological phase transition can be realized in C u2Te , while the nontrivial phase in A g2Te is stable against strain. Their dynamic and thermal stabilities are further confirmed by employing phonon calculations and ab initio molecular dynamic simulations.

  18. Infrared waveguide fabrications with an E-beam evaporated chalcogenide glass film

    Science.gov (United States)

    Yang, X. M.; Zhang, Yaping; Syed, Ahad

    2015-04-01

    Chalcogenide glasses have a variety of unique optical properties due to the intrinsic structural flexibility and bonds metastability. They are desirable materials for many applications, such as infrared communication sensors, holographic grating, optical imaging, and ultrafast nonlinear optic devices. Here, we introduce a novel electron-beam evaporation process to deposit the good quality arsenic trisulfide (As2S3) films and then the As2S3 films were used to fabricate the As2S3 waveguides with three approaches. The first method is photoresist lift-off. Because of the restriction of thermal budget of photoresist, the As2S3 film must be deposited at the room temperature. The second one is the silicon dioxide lift-off process on sapphire substrates, in which the As2S3 film could be evaporated at a high temperature (>180 °C) for better film quality. The third one is the plasma etching process with a metal protective thin layer in the pattern development process.

  19. The use of castor oil and ricinoleic acid in lead chalcogenide nanocrystal synthesis

    Science.gov (United States)

    Kyobe, Joseph W. M.; Mubofu, Egid B.; Makame, Yahya M. M.; Mlowe, Sixberth; Revaprasadu, Neerish

    2016-08-01

    A green solution-based thermolysis method for the synthesis of lead chalcogenide (PbE, E = S, Se, Te) nanocrystals in castor oil (CSTO) and its isolate ricinoleic acid (RA) is described. The blue shift observed from the optical spectra of CSTO and RA-capped PbE nanocrystals (NCs) confirmed the evidence of quantum confinement. The dimensions of PbE NCs obtained from NIR absorption spectra, transmission electron microscopy (TEM), and X-ray diffraction (XRD) studies were in good agreement. The particle sizes estimated were in the range of 20, 25, and 130 nm for castor oil-capped PbS, PbSe, and PbTe, respectively. Well-defined close to cubic-shaped particles were observed in the scanning electron microscopy (SEM) images of PbSe and PbTe nanocrystals. The high-resolution TEM and selective area electron diffraction (SAED) micrographs of the as-synthesized crystalline PbE NCs showed distinct lattice fringes with d-spacing distances corroborating with the standard values reported in literature.

  20. Optical properties and local structure of Dy3+-doped chalcogenide and chalcohalide glasses

    Institute of Scientific and Technical Information of China (English)

    TANG Gao; YANG Zhiyong; LUO Lan; CHEN Wei

    2008-01-01

    Dy3+-doped Ge-Ga-Se chalcogenide glasses and GeSe2-Ga2Se3-CsI chalcohalide glasses were prepared. The absorption, emission properties, and local structure of the glasses were investigated. When excited at 808 nm diode laser, intense 1.32 and 1.55 μm near-infrared luminescence were observed with full width at half maximum (FWHM) of about 90 and 50 rim, respectively. The lifetime of the 1.32 μm emission varied due to changes in the local structure surrounding Dy3+ ions. The longest lifetime was over 2.5 ms, and the value was signifi-cantly higher than that in other Dy3+-doped glasses. Some other spectroscopic parameters were calculated by using Judd-Ofelt theory. Meanwhile, Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses showed good infrared transmittance. As a result, Dy3+-doped Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses were believed to be useful hosts for 1.3 μm optical fiber amplifier.

  1. High-pressure and temperature-induced structural, elastic, and thermodynamical properties of strontium chalcogenides

    Science.gov (United States)

    Varshney, Dinesh; Jain, S.; Shriya, S.; Khenata, R.

    2016-09-01

    Pressure- and temperature-dependent mechanical, elastic, and thermodynamical properties of rock salt to CsCl structures in semiconducting Sr X ( X = O, S, Se, and Te) chalcogenides are presented based on model interatomic interaction potential with emphasis on charge transfer interactions, covalency effect, and zero point energy effects apart from long-range Coulomb, short-range overlap repulsion extended and van der Waals interactions. The developed potential with non-central forces validates the Cauchy discrepancy among elastic constants. The volume collapse ( V P/ V 0) in terms of compressions in Sr X at higher pressure indicates the mechanical stiffening of lattice. The expansion of Sr X lattice is inferred from steep increase in V T/ V 0 and is attributed to thermal softening of Sr X lattice. We also present the results for the temperature-dependent behaviors of hardness, heat capacity, and thermal expansion coefficient. From the Pugh's ratio (ϕ = B T /G H), the Poisson's ratio ( ν) and the Cauchy's pressure ( C 12- C 44), we classify SrO as ductile but SrS, SrSe, and SrTe are brittle material. To our knowledge these are the first quantitative theoretical prediction of the pressure and temperature dependence of mechanical stiffening, thermally softening, and brittle nature of Sr X ( X = O, S, Se, and Te) and still await experimental confirmations.

  2. Surface functionalization of two-dimensional metal chalcogenides by Lewis acid-base chemistry

    Science.gov (United States)

    Lei, Sidong; Wang, Xifan; Li, Bo; Kang, Jiahao; He, Yongmin; George, Antony; Ge, Liehui; Gong, Yongji; Dong, Pei; Jin, Zehua; Brunetto, Gustavo; Chen, Weibing; Lin, Zuan-Tao; Baines, Robert; Galvão, Douglas S.; Lou, Jun; Barrera, Enrique; Banerjee, Kaustav; Vajtai, Robert; Ajayan, Pulickel

    2016-05-01

    Precise control of the electronic surface states of two-dimensional (2D) materials could improve their versatility and widen their applicability in electronics and sensing. To this end, chemical surface functionalization has been used to adjust the electronic properties of 2D materials. So far, however, chemical functionalization has relied on lattice defects and physisorption methods that inevitably modify the topological characteristics of the atomic layers. Here we make use of the lone pair electrons found in most of 2D metal chalcogenides and report a functionalization method via a Lewis acid-base reaction that does not alter the host structure. Atomic layers of n-type InSe react with Ti4+ to form planar p-type [Ti4+n(InSe)] coordination complexes. Using this strategy, we fabricate planar p-n junctions on 2D InSe with improved rectification and photovoltaic properties, without requiring heterostructure growth procedures or device fabrication processes. We also show that this functionalization approach works with other Lewis acids (such as B3+, Al3+ and Sn4+) and can be applied to other 2D materials (for example MoS2, MoSe2). Finally, we show that it is possible to use Lewis acid-base chemistry as a bridge to connect molecules to 2D atomic layers and fabricate a proof-of-principle dye-sensitized photosensing device.

  3. Non-Newtonian flow of an ultralow-melting chalcogenide liquid in strongly confined geometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Siyuan; Jain, Chhavi; Wondraczek, Katrin; Kobelke, Jens [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Wondraczek, Lothar [Otto Schott Institute of Material Research (OSIM), Friedrich Schiller University Jena, Fraunhoferstr. 6, 07743 Jena (Germany); Troles, Johann; Caillaud, Celine [Université de Rennes I, Equipe Verres et Céramiques, UMR 6226 Sciences Chimiques de Rennes, Campus de Beaulieu, 35042 Rennes (France); Schmidt, Markus A., E-mail: markus.schmidt@ipht-jena.de [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Otto Schott Institute of Material Research (OSIM), Friedrich Schiller University Jena, Fraunhoferstr. 6, 07743 Jena (Germany)

    2015-05-18

    The flow of high-viscosity liquids inside micrometer-size holes can be substantially different from the flow in the bulk, non-confined state of the same liquid. Such non-Newtonian behavior can be employed to generate structural anisotropy in the frozen-in liquid, i.e., in the glassy state. Here, we report on the observation of non-Newtonian flow of an ultralow melting chalcogenide glass inside a silica microcapillary, leading to a strong deviation of the shear viscosity from its value in the bulk material. In particular, we experimentally show that the viscosity is radius-dependent, which is a clear indication that the microscopic rearrangement of the glass network needs to be considered if the lateral confinement falls below a certain limit. The experiments have been conducted using pressure-assisted melt filling, which provides access to the rheological properties of high-viscosity melt flow under previously inaccessible experimental conditions. The resulting flow-induced structural anisotropy can pave the way towards integration of anisotropic glasses inside hybrid photonic waveguides.

  4. Lead Chalcogenide on Silicon Infrared Focal Plane Arrays for Thermal Imaging(Review Paper

    Directory of Open Access Journals (Sweden)

    Hans Zogg

    2001-01-01

    Full Text Available "Narrow gap IV-VI [lead chalcogenides like Pbl-xSnxSe and PbTe] layers grown epitaxially on silicon( III substrates by molecular beam epitaxy exhibit high quality despite the large lattice and thermal expansion mismatch. A CaF2 buffer layer is employed for compatibility. Due to easy glide of misfit dislocations in the IV- VI layers, thei1rtal strains relax even at cryogenic. temperatures and after many temperature cyclings. The high permittivities of the IV- VI layers effectively shield the electric fields from charged defects. Higher quality devices are obtained from lower quality material, at variance to narrow gap 11- VI and 111- V compounds. Material characterisation and sensor array properties have been reviewed. Schottky barrier or p-n+ sensor arrays have been delineated using standard photolithography. At low temperatures, the sensitivities are limited by defects, mainly dislocations, and the device performance is predicted by the dislocation density. At higher temperatures, the ultimate theoretical sensitivity is obtained with Schottky barrier devices despite large mismatch and with only 3 µm thickness of the layers. First chara'cterisations of a 96 x 128 array on a silicon substrate containing the read-out circuits show that the concept is functional and gives high yield.

  5. Ellipsometric Characterization of Thin Films from Multicomponent Chalcogenide Glasses for Application in Modern Optical Devices

    Directory of Open Access Journals (Sweden)

    R. Todorov

    2013-01-01

    Full Text Available A review is given on the application of the reflectance ellipsometry for optical characterization of bulk materials and thin films with thickness between λ/20 and 2λ (at λ=632.8 nm. The knowledge of the optical constants (refractive index, n, and extinction coefficient, k of thin films is of a great importance from the point of view of modelling and controlling the manufacture of various optical elements, such as waveguides, diffraction gratings, and microlenses. The presented results concern the optical properties of thin films from multicomponent chalcogenide glasses on the base of As2S3 and GeS2 determined by multiple-angle-of-incidence ellipsometry and regarded as a function of the composition and thickness. The homogeneity of the films is verified by applying single-angle calculations at different angles. Due to decomposition of the bulk glass during thermal evaporation, an optical inhomogeneity of the thin As (Ge-S-Bi(Tl films is observed. The profile of n in depth of thin As-S-Tl (Bi films was investigated by evaporation of discrete layers. It is demonstrated that homogenous layers from the previous compounds with controlled composition can be deposited by coevaporation of As2S3 and metals or their compounds (Bi, Tl, In2S3.

  6. Studies of non-vacuum processing of Cu-chalcogenide thin films.

    Science.gov (United States)

    El Hamri, E; Meddah, M; Boulkadat, L; Elfanaoui, A; Bouabid, K; Nya, M; Portier, X; Ihlal, A

    2012-08-01

    Cu-chalcogenide thin films were prepared using a two stage method: one step electrodeposition of CuISe and CIGSe, and the sulfurisation of CISe to prepare CISSe thin films. The films were deposited on different substrates: Mo and ITO coated glass. The optimum potentials for electrodeposition of CISe and CIGSe films were respectively selected in the range -400 to -550 mV and -650 to -700 mV (vs. SCE). The electrodeposited layers were firmly adhesive. The well known chalcopyrite structure appears after annealing at 400 degrees C under Argon for CISe. The band gap value deduced from the optical measurements is close to 1 eV. To increase this value, addition of gallium in the aqueous electrolytic solution was performed. A band gap value as high as 1.26 eV was recorded on the obtained CIGSe films. Sulfurisation of CISe layers under 5% H2S/Ar atmosphere lead to a shift of the position of the principal XRD peaks indicating the substitution of selenium atoms by sulfur atoms and thus the formation of the quaternary CISSe. Optical measurements performed on this quaternary compound show that our films exhibit a band gap value scaling from 1 eV to 1.4 eV depending on the amount of sulphur incorporated into the layers during the heat treatments.

  7. Highly efficient cascaded amplification using Pr(3+)-doped mid-infrared chalcogenide fiber amplifiers.

    Science.gov (United States)

    Hu, Jonathan; Menyuk, Curtis R; Wei, Chengli; Brandon Shaw, L; Sanghera, Jasbinder S; Aggarwal, Ishwar D

    2015-08-15

    We computationally investigate cascaded amplification in a three-level mid-infrared (IR) Pr(3+)-doped chalcogenide fiber amplifier. The overlap of the cross-sections in the transitions (3)H(6)→(3)H(5) and (3)H(5)→(3)H(4) enable both transitions to simultaneously amplify a single wavelength in the range between 4.25 μm and 4.55 μm. High gain and low noise are achieved simultaneously if the signal is at 4.5 μm. We show that 45% of pump power that is injected at 2 μm can be shifted to 4.5 μm. The efficiency of using a mid-IR fiber amplifier is higher than what can be achieved by using mid-IR supercontinuum generation, which has been estimated at 25%. This mid-IR fiber amplifier can be used in conjunction with quantum cascade lasers to obtain a tunable, high-power mid-IR source.

  8. Silicon-based chalcogenide: Unexpected quantum spin Hall insulator with sizable band gap

    Science.gov (United States)

    Zhang, Run-wu; Zhang, Chang-wen; Ji, Wei-xiao; Li, Ping; Wang, Pei-ji; Li, Sheng-shi; Yan, Shi-shen

    2016-10-01

    Searching for two-dimensional (2D) silicon-based topological materials is imperative for the development of various innovative devices. Here, by using first-principles calculations, we discover the silicon-based chalcogenide Si2Te2 film to be a 2D quantum spin Hall (QSH) insulator with a fundamental band gap of 0.34 eV, which can be tunable under external strain. This nontrivial topological phase stems from band inversion between the Si-px,y and Te-px,y orbitals, demonstrated by a single pair of topologically protected helical edge states with Dirac point located in the bulk gap. Notably, the characteristic properties of edge states, such as the Fermi velocity and edge shape, can be engineered by edge modifications. Additionally, the BN sheet is an ideal substrate for the experimental realization of Si2Te2 films, without destroying its nontrivial topology. Our works open a meaningful route for designing topological spintronics devices based on 2D silicon-based films.

  9. Optical properties change in laser-induced Te/As2Se3 chalcogenide thin films

    Science.gov (United States)

    Behera, Mukta; Naik, Ramakanta

    2016-10-01

    In the present work, we report the change in optical parameters due to the deposition and photo-induced diffusion of Te layer into the chalcogenide As2Se3 film. The photo-diffusion creates a solid solution of As-Se-Te which has potential application in optical devices. The Te/As2Se3 bilayer films prepared by thermal evaporation technique were studied by various experimental techniques. The photo-diffusion of Te into As2Se3 matrix was done by 532-nm laser irradiation. The structure of the As2Se3, as-prepared and irradiated Te/As2Se3 films was studied by X-ray diffraction which were amorphous in nature. The presence of all the elements was checked by energy-dispersive X-ray analysis, and the optical transmission spectra were recorded by Fourier transform infrared spectrometer. The optical band gap is reduced by the deposition and diffusion of Te into As2Se3 film which is due to the increase in density of defect states in the gap region. The transmission is decreased, whereas the absorption efficiency is increased with the increase in disorderness. The X-ray photoelectron spectroscopy carried out on these films gives information about the bonding change due to the photo-diffusion process. Therefore, this is an important result which will open up new directions for the application of this material in semiconducting devices.

  10. A new method to study complex materials in solid state chemistry: application to chalcogenide materials

    Science.gov (United States)

    Lippens, P. E.; Olivier-Fourcade, J.; Jumas, J. C.

    1998-08-01

    We show that a combined application of Mössbauer spectroscopy and other experimental tools such as X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and nuclear magnetic resonance provides a coherent picture of the local electronic structure in chalcogenide materials. In order to develop this idea we propose an analysis of the Sn, Sb and Te local electronic structures for three different systems of materials. The first example concerns the In Sn S system. We show that Li insertion in In16Sn4S32 leads to changes of the Sn oxidation states from Sn(IV) to Sn(II). The second example concerns materials of the Tl Sb S system. We show that variations of the 121Sb Mössbauer isomer shift and surface of the first peak of the X-ray absorption spectra at the Sb LIII edge can be linearly correlated because of the main influence of the Sb 5s electrons. This is explained by changes in the local environment of the Sb atoms. The last example concerns the crystalline phases of the Tl Sn Te system. The formal oxidation numbers of the Te atoms are determined from 125Te Mössbauer spectroscopy and X-ray photoelectron spectroscopy. They are related to the different types of bonds involving the Te atoms in the Tl Sn Te compounds.

  11. Superior Electrical Conductivity in Hydrogenated Layered Ternary Chalcogenide Nanosheets for Flexible All-Solid-State Supercapacitors.

    Science.gov (United States)

    Hu, Xin; Shao, Wei; Hang, Xudong; Zhang, Xiaodong; Zhu, Wenguang; Xie, Yi

    2016-05-04

    As the properties of ultrathin two-dimensional (2D) crystals are strongly related to their electronic structures, more and more attempts were carried out to tune their electronic structures to meet the high standards for the construction of next-generation smart electronics. Herein, for the first time, we show that the conductive nature of layered ternary chalcogenide with formula of Cu2 WS4 can be switched from semiconducting to metallic by hydrogen incorporation, accompanied by a high increase in electrical conductivity. In detail, the room-temperature electrical conductivity of hydrogenated-Cu2 WS4 nanosheet film was almost 10(10) times higher than that of pristine bulk sample with a value of about 2.9×10(4)  S m(-1) , which is among the best values for conductive 2D nanosheets. In addition, the metallicity in the hydrogenated-Cu2 WS4 is robust and can be retained under high-temperature treatment. The fabricated all-solid-state flexible supercapacitor based on the hydrogenated-Cu2 WS4 nanosheet film shows promising electrochemical performances with capacitance of 583.3 F cm(-3) at a current density of 0.31 A cm(-3) . This work not only offers a prototype material for the study of electronic structure regulation in 2D crystals, but also paves the way in searching for highly conductive electrodes.

  12. Pressure induced stiffening, thermal softening of bulk modulus and brittle nature of mercury chalcogenides

    Science.gov (United States)

    Varshney, Dinesh; Shriya, Swarna; Sapkale, Raju; Varshney, Meenu; Ameri, M.

    2015-07-01

    The pressure and temperature dependent elastic properties of mercury chalcogenides (HgX; X = S, Se and Te) with pressure induced structural transition from ZnS-type (B3) to NaCl-type (B1) structure have been analyzed within the framework of a model interionic interaction potential with long-range Coulomb and charge transfer interactions, short-range overlap repulsion and van der Waals (vdW) interactions as well as zero point energy effects. Emphasis is on the evaluation of the Bulk modulus with pressure and temperature dependency to yield the Poisson's ratio ν, the Pugh ratio ϕ, anisotropy parameter, Shear and Young's modulus, Lamé's constant, Klein man parameter, elastic wave velocity and Debye temperature. The Poisson's ratio behavior infers that HgX are brittle in nature. To our knowledge this is the first quantitative theoretical prediction of the pressure dependence of elastic and thermodynamical properties explicitly the ductile (brittle) nature of HgX and still awaits experimental confirmations.

  13. Carbon supported ruthenium chalcogenide as cathode catalyst in a microfluidic formic acid fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gago, A.S.; Alonso-Vante, N. [Laboratory of Electrocatalysis, UMR-CNRS 6503, Universite de Poitiers, 40 Avenue du Recteur Pineau, F-86022 Potiers Cedex (France); Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C. Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76703, Queretaro (Mexico)

    2011-02-01

    This work reports the electrochemical measurements of 20 wt.% Ru{sub x}Se{sub y}/C for oxygen reduction reaction (ORR) in presence of different concentration of HCOOH and its use as cathode catalyst in a microfluidic formic acid fuel cell ({mu}FAFC). The results were compared to those obtained with commercial Pt/C. Half-cell electrochemical measurements showed that the chalcogenide catalyst has a high tolerance and selectivity towards ORR in electrolytes containing up to 0.1 M HCOOH. The depolarization effect was higher on Pt/C than on Ru{sub x}Se{sub y}/C by a factor of ca. 23. Both catalysts were evaluated as cathode of a {mu}FAFC operating with different concentrations of HCOOH. When 0.5 M HCOOH was used, maximum current densities of 11.44 mA cm{sup -2} and 4.44 mA cm{sup -2} were obtained when the cathode was Ru{sub x}Se{sub y}/C and Pt/C, respectively. At 0.5 M HCOOH, the peak power density of the {mu}FAFC was similar for both catalysts, ca. 1.9 mW cm{sup -2}. At 5 M HCOOH the power density of the {mu}FAFC using Ru{sub x}Se{sub y}, was 9.3 times higher than the obtained with Pt/C. (author)

  14. Photoelectric properties of defect chalcogenide HgGa2X4 (x=S, Se, Te)

    Science.gov (United States)

    Sharma, Ramesh; Dwivedi, Shalini; Sharma, Yamini

    2016-05-01

    We present results of ab initio study of ordered vacancy compounds of mercury. The electronic structure, charge density, optical and transport properties of the semiconductor family HgGa2X4 (X=S, Se, Te) are calculated using the full potential linearized augmented plane wave method which is based on the density functional theory. A direct bandgap is observed in these compounds, which reduces in the order S>Se>Te. From the density of states it is observed that there is strong hybridization of Hg-d, Ga-d and X-p states. The optical properties show a red shift with increasing size and atomic no. of the chalcogenide atoms. We have also reported the transport properties of mercury thiogallates for the first time. The selenide compound exhibits n-type nature whereas HgGa2S4 and HgGa2Te4 show p-type behavior. The power factor and ZT for the HGS increases at low temperatures, the figure of merit is highest for HgGa2Se4 (1.17) at 19 K.

  15. Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors.

    Science.gov (United States)

    Li, Song-Lin; Tsukagoshi, Kazuhito; Orgiu, Emanuele; Samorì, Paolo

    2016-01-01

    Two-dimensional (2D) van der Waals semiconductors represent the thinnest, air stable semiconducting materials known. Their unique optical, electronic and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. However, the charge transport behavior in 2D semiconductors is more susceptible to external surroundings (e.g. gaseous adsorbates from air and trapped charges in substrates) and their electronic performance is generally lower than corresponding bulk materials due to the fact that the surface and bulk coincide. In this article, we review recent progress on the charge transport properties and carrier mobility engineering of 2D transition metal chalcogenides, with a particular focus on the markedly high dependence of carrier mobility on thickness. We unveil the origin of this unique thickness dependence and elaborate the devised strategies to master it for carrier mobility optimization. Specifically, physical and chemical methods towards the optimization of the major factors influencing the extrinsic transport such as electrode/semiconductor contacts, interfacial Coulomb impurities and atomic defects are discussed. In particular, the use of ad hoc molecules makes it possible to engineer the interface with the dielectric and heal the vacancies in such materials. By casting fresh light on the theoretical and experimental studies, we provide a guide for improving the electronic performance of 2D semiconductors, with the ultimate goal of achieving technologically viable atomically thin (opto)electronics.

  16. Thin film solar cells based on layered chalcogenides: Fundamentals and perspectives of van der Waals epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Jaegermann, W.; Pettenkofer, C.; Lang, O.; Schlaf, R.; Tiefenbacher, S.; Tomm, Y. [Hahn-Meitner-Inst., Berlin (Germany)

    1994-12-31

    The preparation of thin films of layered chalcogenide semiconductors as MX and MX{sub 2} (X = S, Se) based on the concept of van der Waals epitaxy (VDWE) is presented for different substrate/overlayer combinations as GaSe, InSe, SnSe{sub 2}, WS{sub 2} on WSe{sub 2}, GaSe, MoTe{sub 2}, graphite and mica. In all cases stoichiometric films are formed either as epitaxial layers or strongly textured films with the c-axis aligned in spite of strong lattice mismatch. The interfaces are non-reactive and atomically abrupt. The electronic properties of the interfaces are mostly ideal showing band offsets according to the electron affinity rule and no operative interface states. However, doping of the films is still a problem which limits the band bending and the attainable surface photovoltage. The perspectives and preconditions for the further development of layered semiconductor VDWE films for solar cells will be critically discussed.

  17. Magnetoresistance and electrical properties of multi-component copper chalcogenides at pressures up to 50 GPa

    Science.gov (United States)

    Melnikova, Nina; Tebenkov, Alexander; Babushkin, Alexey; Kurochka, Kirill; Phase Transitions Team; Transport Properties Team; Novel Materials Team

    2013-06-01

    Multi-component chalcogenides based on layered semiconductors A3B6 (such as InS, InSe, GaS, GaSe, etc) are new objects of study, they have interesting physical properties and undergo temperature and baric phase transitions. This paper presents the results of a study of the electrical properties and magnetoresistance of CuInS2, CuInSe2, CuInAsS3, CuInAsSe3, CuInSbS3 at pressures up to 50 GPa. High pressures have been generated in the cell with synthetic carbonado-type diamond anvils that can be used as electric contacts. Electric properties at high pressure have been investigated on dc current and by means of impedance spectroscopy. Magnetoresistance has been measured in transverse magnetic field. The pressure ranges of noticeable changes in a behavior of magnetoresistance, of impedance and admittance, tangent of loss angle, relaxation time upon a pressure increase and a pressure decrease are established. This behavior of physical parameters can be due to structural transitions and due to a change of electron structure. This work was supported in part by the Russian Foundation for Basic Research, project no. 13-02-00633.

  18. 43 CFR 19.8 - Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest...

    Science.gov (United States)

    2010-10-01

    ... patents, and mineral leasing within National Forest Wilderness. 19.8 Section 19.8 Public Lands: Interior... § 19.8 Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest... locations, mineral patents, and mineral leasing within National Forest Wilderness are contained in...

  19. All-optical demultiplexing of 1.28~Tb/s to 10~Gb/s using a chalcogenide photonic chip

    DEFF Research Database (Denmark)

    Vo, T.D.; Hu, Hao; Galili, Michael;

    2010-01-01

    We report the first demonstration of all-optical Tbaud switching on a compact photonic chip. A 1.28 Tbaud return-to-zero signal was demultiplexed via four-wave mixing in a highly nonlinear, dispersion-engineered 7-cm Chalcogenide planar waveguide.......We report the first demonstration of all-optical Tbaud switching on a compact photonic chip. A 1.28 Tbaud return-to-zero signal was demultiplexed via four-wave mixing in a highly nonlinear, dispersion-engineered 7-cm Chalcogenide planar waveguide....

  20. A first principles study of phase stability, bonding, electronic and lattice dynamical properties of beryllium chalcogenides at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Dabhi, Shweta [Department of Physics, Maharaja Krishnakumarsinhji Bhavnagar University, Bhavnagar 364001 (India); Mankad, Venu [Central Institute of Plastic Engineering and Technology, Ahmedabad (India); Jha, Prafulla K., E-mail: prafullaj@yahoo.com [Department of Physics, Faculty of Science, The M.S. University of Baroda, Vadodara 390002 (India)

    2014-12-25

    Highlights: • First principles calculations are performed for BeS, BeSe and BeTe in B3, B8 and B1 phases. • They are indirect wide band gap semiconductors stable in B3 phase at ambient condition. • Phonon calculations at ambient and high pressure are reported. • The NiAs phase is dynamically stable at high pressure. - Abstract: The present paper reports a detailed and systematic theoretical study of structural, mechanical, electronic, vibrational and thermodynamical properties of three beryllium chalcogenides BeS, BeSe and BeTe in zinc blende, NiAs and rock salt phases by performing ab initio calculations based on density-functional theory. The calculated value of lattice constants and bulk modulus are compared with the available experimental and other theoretical data and found to agree reasonably well. These compounds are indirect wide band gap semiconductors with a partially ionic contribution in all considered three phases. The zinc blende phase of these chalcogenides is found stable at ambient condition and phase transition from zinc blende to NiAs structure is found to occur. The bulk modulus, its pressure derivative, anisotropic factor, Poission’s ratio, Young’s modulus for these are also calculated and discussed. The phonon dispersion curves of these beryllium chalcogenides in zinc blende phase depict their dynamical stability in this phase at ambient condition. We have also estimated the temperature variation of specific heat at constant volume, entropy and Debye temperature for these compounds in zinc blende phase. The variation of lattice-specific heat with temperature obeys the classical Dulong–Petit’s law at high temperature, while at low-temperature it obeys the Debye’s T{sup 3} law.

  1. Ultrafast laser fabrication of low-loss waveguides in chalcogenide glass with 0.65 dB/cm loss.

    Science.gov (United States)

    McMillen, Ben; Zhang, Botao; Chen, Kevin P; Benayas, Antonio; Jaque, Daniel

    2012-05-01

    This Letter reports on the fabrication of low-loss waveguides in gallium-lanthanum-sulfide chalcogenide glasses using an ultrafast laser. Spatial beam shaping and temporal pulse width tuning were used to optimize the guided mode profiles and optical loss of laser-written waveguides. Highly symmetric single-mode waveguides guiding at 1560 nm with a loss of 0.65  dB/cm were fabricated using 1.5 ps laser pulses. This Letter suggests a pathway to produce high quality optical waveguides in substrates with strong nonlinearity using the ultrafast laser direct writing technique.

  2. Time-resolved terahertz spectroscopy of charge carrier dynamics in the chalcogenide glass As30Se30Te40 [Invited

    DEFF Research Database (Denmark)

    Wang, Tianwu; Romanova, Elena A.; Abdel-Moneim, Nabil;

    2016-01-01

    Broadband (1.6-18 THz) terahertz time-domain spectroscopy (THz-TDS) and time-resolved terahertz spectroscopy (TRTS) were performed on a 54 mu m thick chalcogenide glass (As30Se30Te40) sample with a two-color laser-induced air plasma THz system in transmission and reflection modes, respectively. Two...... absorption bands at 2-3 and 5-8 THz were observed. TRTS reveals an ultrafast relaxation process of the photoinduced carrier response, well described by a rate equation model with a finite concentration of mid-bandgap trap states for self-trapped excitons. The photoinduced conductivity can be well described...

  3. Demonstration of CO2-laser power delivery through chalcogenide-glass fiber with negative-curvature hollow core.

    Science.gov (United States)

    Kosolapov, Alexey F; Pryamikov, Andrey D; Biriukov, Alexander S; Shiryaev, Vladimir S; Astapovich, Maxim S; Snopatin, Gennady E; Plotnichenko, Victor G; Churbanov, Mikhail F; Dianov, Evgeny M

    2011-12-05

    A technologically simple optical fiber cross-section structure with a negative-curvature hollow-core has been proposed for the delivery of the CO2 laser radiation. The structure was optimized numerically and then realized using Te20As30Se50 (TAS) chalcogenide glass. Guidance of the 10.6 µm СО2-laser radiation through this TAS-glass hollow-core fiber has been demonstrated. The loss at λ=10.6 μm was amounted ~11 dB/m. A resonance behavior of the fiber bend loss as a function of the bend radius has been revealed.

  4. Ultrafast spectroscopic investigations of cadmium chalcogenides: Nanoscale electronic relaxation and transfer

    Science.gov (United States)

    Spann, Bryan Thomas

    Harnessing solar energy more effectively remains one of the most important scientific challenges in recent history. Various strategies have been developed to capture the sun's energy to generate usable electricity. Recently, advances in chemistry have allowed researchers to synthesize semiconducting nanocrystals which show great promise in capturing and converting solar energy in a cheap and efficient way. In this dissertation, aspects of energy conversion processes in semiconducting nanocrystals are explored to elucidate their potential for photovoltaic applications. Various forms of linear and non-linear optical spectroscopy techniques were employed to explore electronic relaxation and transfer phenomena in nanoscale cadmium chalcogenide materials and heterojunctions. Ultrafast transient absorption studies were performed on various sizes of CdSe quantum dots (QDs) and quantum rods (QRs) with similar bandedge energies. These studies reviled that QRs have increased intraband relaxation times when compared with QDs as a result of an ultrafast formation of a 1D exciton along the elongated axis of the QR. The formation of the 1D exciton reduces the electron-to-hole scattering potential, consequently reducing the Auger thermalization mechanism. Furthermore, QD samples made in film form showed increased intraband relaxation times as a result of a hydrazine treatment which removed (in part) the organic ligands attached to the surface. As a result of removing the ligands, the ligand based relaxation pathway for the holes was also reduced, causing longer intraband relaxation. In addition to the studies on CdSe nanocrystals (NCs), ultrafast spectroscopy was used to study aspects of charge transfer in CdS -- TiO2 NC heterojunctions. This study revealed a means of increasing photo-induced ultrafast charge transfer in successive ionic layer adsorption and reaction (SILAR) CdS--TiO2 NC heterojunctions using pulsed laser sintering of TiO2 nanocrystals. The enhanced charge

  5. Engineering of lead chalcogenide nanostructures for carrier multiplication: Core/shell, 1D, and 2D

    Science.gov (United States)

    Lin, Qianglu

    Near infrared emitting semiconductors have been used widely in industry especially in solar-cell fabrications. The efficiency of single junction solar-cell can reach the Shockley-Queisser limit by using optimum band gap material such as silicon and cadmium telluride. The theoretical efficiency can be further enhanced through carrier multiplication, in which a high energy photon is absorbed and more than one electron-hole pair can be generated, reaching more than 100% quantum efficiency in the high energy region of sunlight. The realization of more than unity external quantum efficiency in lead selenide quantum dots solar cell has motivated vast investigation on lowering the carrier multiplication threshold and further improving the efficiency. This dissertation focuses on synthesis of lead chalcogenide nanostructures for their optical spectroscopy studies. PbSe/CdSe core/shell quantum dots were synthesized by cation exchange to obtain thick shells (up to 14 monolayers) for studies of visible and near infrared dual band emissions and carrier multiplication efficiency. By examining the reaction mechanism, a thermodynamic and a kinetic model are introduced to explain the vacancy driven cation exchange. As indicated by the effective mass model, PbSe/CdSe core/shell quantum dots has quasi-type-II band alignment, possessing electron delocalized through the entire quantum dot and hole localized in the core, which breaks down the symmetry of energy levels in the conduction and valence band, leading to hot-hole-assisted efficient multi-exciton generation and a lower carrier multiplication threshold to the theoretical value. For further investigation of carrier multiplication study, PbTe, possessing the highest efficiency among lead chalcogenides due to slow intraband cooling, is synthesized in one-dimensional and two-dimensional nanostructures. By using dodecanethiol as the surfactant, PbTe NRs can be prepared with high uniformity in width and resulted in fine quantum

  6. Mineral Fiber Toxicology

    Science.gov (United States)

    The chemical and physical properties of different forms of mineral fibers impact biopersistence and pathology in the lung. Fiber chemistry, length, aspect ratio, surface area and dose are critical factors determining mineral fiber-associated health effects including cancer and as...

  7. Vitamins, Minerals, and Mood

    Science.gov (United States)

    Kaplan, Bonnie J.; Crawford, Susan G.; Field, Catherine J.; Simpson, J. Steven A.

    2007-01-01

    In this article, the authors explore the breadth and depth of published research linking dietary vitamins and minerals (micronutrients) to mood. Since the 1920s, there have been many studies on individual vitamins (especially B vitamins and Vitamins C, D, and E), minerals (calcium, chromium, iron, magnesium, zinc, and selenium), and vitamin-like…

  8. Mineral commodity summaries 2017

    Science.gov (United States)

    Ober, Joyce A.

    2017-01-31

    This report is the earliest Government publication to furnish estimates covering 2016 nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for more than 90 individual minerals and materials.

  9. Ferromagnetism modulation by phase change in Mn-doped GeTe chalcogenide magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Adam Abdalla Elbashir [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China); Alneelain University, Faculty of Science and Technology, Khartoum (Sudan); Cheng, Xiaomin; Guan, Xiawei; Miao, Xiangshui [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China)

    2014-12-15

    In this work, an effective method to modulate the ferromagnetic properties of Mn-doped GeTe chalcogenide-based phase change materials is presented. The microstructure of the phase change magnetic material Ge{sub 1-x} Mn{sub x} Te thin films was studied. The X-ray diffraction results demonstrate that the as-deposited films are amorphous, and the crystalline films are formed after annealing at 350 C for 10 min. Crystallographic structure investigation shows the existence of some secondary magnetic phases. The lattice parameters of Ge{sub 1-x} Mn{sub x} Te (x = 0.04, 0.12 and 0.15) thin films are found to be slightly different with changes of Mn compositions. The structural analysis clearly indicates that all the films have a stable rhombohedral face-centered cubic polycrystalline structure. The magnetic properties of the amorphous and crystalline Ge{sub 0.96}Mn{sub 0.04}Te were investigated. The measurements of magnetization (M) as a function of the magnetic field (H) show that both amorphous and crystalline phases of Ge{sub 0.96}Mn{sub 0.04}Te thin film are ferromagnetic and there is drastic variation between amorphous and crystalline states. The temperature (T) dependence of magnetizations at zero field cooling (ZFC) and field cooling (FC) conditions of the crystalline Ge{sub 0.96}Mn{sub 0.04}Te thin film under different applied magnetic fields were performed. The measured data at 100 and 300 Oe applied magnetic fields show large bifurcations in the ZFC and FC curves while on the 5,000 Oe magnetic field there is no deviation. (orig.)

  10. Marine Mineral Exploration

    DEFF Research Database (Denmark)

    The past 20 years have seen extensive marine exploration work by the major industrialized countries. Studies have, in part, been concentrated on Pacific manganese nodule occurrences and on massive sulfides on mid-oceanic ridges. An international jurisdictional framework of the sea-bed mineral...... in EEZ areas are fairly unknown; many areas need detailed mapping and mineral exploration, and the majority of coastal or island states with large EEZ areas have little experience in exploration for marine hard minerals. This book describes the systematic steps in marine mineral exploration....... Such exploration requires knowledge of mineral deposits and models of their formation, of geophysical and geochemical exploration methods, and of data evaluation and interpretation methods. These topics are described in detail by an international group of authors. A short description is also given of marine...

  11. Síntese de zeólitas a partir de cinza volante de caldeiras: caracterização física, química e mineralógica Synthesis of zeolites from boiler fly ash: physical, chemical and mineralogical characterization

    Directory of Open Access Journals (Sweden)

    C. A. F. Rocha Junior

    2012-03-01

    chemical, physical and mineralogical characterization methods were carried out: X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, granulometric analysis, differential thermal and thermogravimetric analysis (DTA-TG. The analyses were carried out at the following conditions: 60, 100, 150 and 190 °C, Na2O/Al2O3 molar ratio of 5 and Si/Al molar ratio ranging from 2.12 to 15, and reaction time of 24 h. The results of the fly characterization demonstrate its enormous potential as raw material for the zeolite synthesis. SiO2 and Al2O3 represent more than 50% of its composition, mineralogical phases defined, low humidity content, low particle size (d90 < 10 µm, among others. Mineralogical analyses of the synthesized products showed the formation of some zeolite types, as follow: analcime, phillipsite, sodalite, zeolite P and tobermorite. The results show that the mixture fly ash-microsilica in these reaction conditions point to a promising material for zeolite synthesis.

  12. Two new ternary lanthanide antimony chalcogenides: Yb4Sb2S11.25 and Tm4Sb2Se11.68 containing chalcogenide Q2- and dichalcogenide (Q2)2- anions

    Science.gov (United States)

    Babo, Jean-Marie; Albrecht-Schmitt, Thomas E.

    2012-03-01

    Dark red and dark brown crystals of Yb4Sb2S11.25 and Tm8Sb4Se11.68, respectively, were obtained from the reaction of the elements in Sb2Q3 (Q=S, Se) fluxes. Both non-stoichiometric compounds are orthorhombic and crystallize in the same space group Pnnm, with two formula units per unit cell (a=12.446(2), b=5.341(1), c=12.058(2) for sulfide and a=13.126(2), b=5.623(1), c=12.499(2) for the selenide). Their crystal structures are dominated by lanthanide-chalcogenide polyhedra (CN=7 and 8), which share corners, edges, triangular- and square-faces to form a three-dimensional framework embedding antinomy cations. The latter are coordinated by three sulfide anions with 5(1+2+2) secondary contacts forming basically infinite chains running along [0 1 0]. The chalcogens in both compounds form chalcogenide Q2- and dichalcogenide (Q2)2- anionic units. The optical analysis made on those compounds shows that both are semiconductors with band gap of 1.71 and 1.22 eV for Yb4Sb2S11.25 and Tm4Sb2Se11.75, respectively.

  13. Destruction-polymerization transformations as a source of radiation-induced extended defects in chalcogenide glassy semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, Oleh [Institute of Physics, Jan Dlugosz University, Al. Armii Krajowej 13/15, 42200, Czestochowa (Poland); Lviv Scientific Research Institute of Materials, SRC ' ' Carat' ' , Stryjska str. 202, 79031 Lviv (Ukraine); Filipecki, Jacek [Lviv Scientific Research Institute of Materials, SRC ' ' Carat' ' , Stryjska str. 202, 79031 Lviv (Ukraine); Shpotyuk, Mykhaylo [Lviv Scientific Research Institute of Materials, SRC ' ' Carat' ' , Stryjska str. 202, 79031 Lviv (Ukraine); Department of Semiconductor Electronics, Lviv Polytechnic National University, Bandery str. 12, 79013 Lviv (Ukraine)

    2013-01-15

    Long-wave shift of the optical transmission spectrum in the region of fundamental optical absorption edge is registered for As{sub 2}S{sub 3} chalcogenide glassy semiconductors after {gamma}-irradiation. This effect is explained in the frameworks of the destruction-polymerization transformations concept by accepting the switching of the heteropolar As-S covalent bonds into homopolar As-As ones. It is assumed that (As{sub 4}{sup +}; S{sub 1}{sup -}) defect pairs are created under such switching. Formula to calculate content of the induced defects in chalcogenide glassy semiconductors is proposed. It is assumed that defects concentration depends on energy of broken covalent bond, bond-switching energy balance, correlation energy, optical band-gap and energy of excitation light. It is shown that theoretically calculated maximally possible content of radiation-induced defects in As{sub 2}S{sub 3} is about 1.6% while concentration of native defects is negligible. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Effect of Sn doping on nonlinear optical properties of quaternary Se-Sn-(Bi,Te) chalcogenide thin films

    Science.gov (United States)

    Yadav, Preeti; Sharma, Ambika

    2015-08-01

    The aim of this work is to report the effect of Sn doping on the third order nonlinear optical properties of chalcogenide Se84-xTe15Bi1.0Snx thin films. Melt quenching technique has been used for the preparation of bulk chalcogenide glasses. Thin films of the studied composition are deposited on cleaned glass substrate by thermal evaporation technique. Optical band gap (Eg) is calculated by using Tauc extrapolation method and is found to increase from 1.27 eV to 1.64 eV with the incorporation of Sn content. Stryland approach is utilized for the calculation of two photon absorption coefficient (β2). The nonlinear refractive index (n2) and third order susceptibility (χ(3) are calculated using Tichy and Ticha approach. The result shows that nonlinear refractive index (n2) follows the same trend as that of linear refractive index (n). The values of n2 of studied composition as compared to pure silica are 1000-5000 times higher.

  15. First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides

    Science.gov (United States)

    Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D.

    2016-08-01

    Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured cell efficiency. Using first-principles calculations based on density functional theory, the optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are then screened with the aim of identifying potential absorber materials for photovoltaic applications. The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev. Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the current-voltage curve, the SLME is calculated from the maximum power output. The role of the nature of the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with II = Cd and Hg, and Cu2-II-SnS4 with II = Cd, Hg, and Zn have a higher theoretical efficiency compared with the materials currently used as absorber layer.

  16. Nonlinear Label-Free Biosensing With High Sensitivity Using As2S3 Chalcogenide Tapered Fiber

    DEFF Research Database (Denmark)

    Markos, Christos; Bang, Ole

    2015-01-01

    We demonstrate an experimentally feasible fiber design, which can act as a highly sensitive, label-free, and selective biosensor using the inherent high nonlinearity of an As2S3 chalcogenide tapered fiber. The surface immobilization of the fiber with an antigen layer can provide the possibility t......, this high sensitivity can be obtained using a low-power 1064-nm microchip laser....

  17. GeS2-In2S3-CsI Chalcogenide Glasses Doped with Rare Earth Ions for Near- and Mid-IR Luminescence.

    Science.gov (United States)

    Li, Legang; Bian, Junyi; Jiao, Qing; Liu, Zijun; Dai, Shixun; Lin, Changgui

    2016-11-21

    Chalcogenide glass has been considered as a promising host for the potential laser gain and amplifier media operating in near- and mid-IR spectral region. In this work, the IR luminescence spectra of rare earth ions (Tm(3+), Er(3+), and Dy(3+)) doped 65GeS2-25In2S3-10CsI chalcogenide glasses were measured under the excitation of an 808 nm laser diode. To the best of our knowledge, it firstly provides the luminescence spectra of a full near- and mid-IR spectral range from 1 to 4 μm in rare earth ions doped chalcogenide glasses. The results of absorption spectra, luminescence spectra, and fluorescence decay curves were obtained in these samples with singly-, co- and triply-doping behaviors of Tm(3+), Er(3+), and Dy(3+) ions. In order to search possible efficient IR emissions, the luminescence behavior was investigated specifically with the variation of doping behaviors and dopant ions, especially in the samples co- and triply-doped active ions. The results suggest that favorable near- and mid-IR luminescence of rare earth ions can be further modified in chalcogenide glasses through an elaborated design of doping behavior and optically active ions.

  18. GeS2–In2S3–CsI Chalcogenide Glasses Doped with Rare Earth Ions for Near- and Mid-IR Luminescence

    Science.gov (United States)

    Li, Legang; Bian, Junyi; Jiao, Qing; Liu, Zijun; Dai, Shixun; Lin, Changgui

    2016-11-01

    Chalcogenide glass has been considered as a promising host for the potential laser gain and amplifier media operating in near- and mid-IR spectral region. In this work, the IR luminescence spectra of rare earth ions (Tm3+, Er3+, and Dy3+) doped 65GeS2–25In2S3–10CsI chalcogenide glasses were measured under the excitation of an 808 nm laser diode. To the best of our knowledge, it firstly provides the luminescence spectra of a full near- and mid-IR spectral range from 1 to 4 μm in rare earth ions doped chalcogenide glasses. The results of absorption spectra, luminescence spectra, and fluorescence decay curves were obtained in these samples with singly-, co- and triply-doping behaviors of Tm3+, Er3+, and Dy3+ ions. In order to search possible efficient IR emissions, the luminescence behavior was investigated specifically with the variation of doping behaviors and dopant ions, especially in the samples co- and triply-doped active ions. The results suggest that favorable near- and mid-IR luminescence of rare earth ions can be further modified in chalcogenide glasses through an elaborated design of doping behavior and optically active ions.

  19. Thulium pumped mid-infrared 0.9–9μm supercontinuum generation in concatenated fluoride and chalcogenide glass fibers

    DEFF Research Database (Denmark)

    Kubat, Irnis; Petersen, Christian Rosenberg; Møller, Uffe Visbech;

    2014-01-01

    We theoretically demonstrate a novel approach for generating Mid-InfraRed SuperContinuum (MIR SC) by using concatenated fluoride and chalcogenide glass fibers pumped with a standard pulsed Thulium (Tm) laser (TFWHM=3.5ps, P0=20kW, νR=30MHz, and Pavg=2W). The fluoride fiber SC is generated in 10m ...

  20. Oceans: Geochemistry and mineral resources

    Digital Repository Service at National Institute of Oceanography (India)

    Joao, H.M.; Paropkari, A

    With increased exploitation of the onshore mineral resources, oceans that cover almost 71% of earth's surface and known as storehouse of minerals, provide a suitable alternative. Amongst the various underwater mineral resources, placer deposits...

  1. Mineral resources of Antarctica

    Science.gov (United States)

    Compiled and edited by Wright, Nancy A.; Williams, Paul L.

    1974-01-01

    Although the existence of mineral deposits in Antarctica is highly probable, the chances of finding them are quite small. Minerals have been found there in great variety but only as occurrences. Manganese nodules, water (as ice), geothermal energy, coal, petroleum, and natural gas are potential resources that could perhaps be exploited in the future. On the basis of known mineral occurrences in Antarctica and relationships between geologic provinces of Antarctica and those of neighboring Gondwana continents, the best discovery probability for a base-metal deposit in any part of Antarctica is in the Andean orogen; it is estimated to be 0.075 (75 chances in 1,000).

  2. sequenceMiner algorithm

    Data.gov (United States)

    National Aeronautics and Space Administration — Detecting and describing anomalies in large repositories of discrete symbol sequences. sequenceMiner has been open-sourced! Download the file below to try it out....

  3. Mineral Commodity Summaries 2009

    Science.gov (United States)

    ,

    2009-01-01

    Each chapter of the 2009 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2008 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Because specific information concerning committed inventory was no longer available from the Defense Logistics Agency, National Defense Stockpile Center, that information, which was included in earlier Mineral Commodity Summaries publications, has been deleted from Mineral Commodity Summaries 2009. National reserves and reserve base information for most mineral commodities found in this report, including those for the United States, are derived from a variety of sources. The ideal source of such information would be comprehensive evaluations that apply the same criteria to deposits in different geographic areas and report the results by country. In the absence of such evaluations, national reserves and reserve base estimates compiled by countries for selected mineral commodities are a primary source of national reserves and reserve base information. Lacking national assessment information by governments, sources such as academic articles, company reports, common business practice, presentations by company representatives, and trade journal articles, or a combination of these, serve as the basis for national reserves and reserve base information reported in the mineral commodity sections of this publication. A national estimate may be assembled from the following: historically reported

  4. [Synthetic mineral fibers].

    Science.gov (United States)

    Boillat, M A

    1999-03-27

    The group of man-made mineral fibres includes slagwool, glasswool, rockwool, glass filaments and microfibres, as well as refractory ceramic fibres. The toxicity of mineral fibres is determined by several factors such as the diameter (ceramic fibres. A slightly elevated standard mortality ratio for lung cancer has been documented in large cohorts of workers (USA, Europe and Canada) exposed to man-made mineral fibres, especially in the early technological phase. It is not possible to determine from these data whether the risk of lung cancer is due to the man-made mineral fibres themselves, in particular due to the lack of data on smoking habits. No increased risk of mesothelioma has been demonstrated in these cohorts. Epidemiological data are insufficient at this time concerning neoplastic diseases in refractory ceramic fibres.

  5. Minerals in environmental technology

    Energy Technology Data Exchange (ETDEWEB)

    Schuiling, R.D. [Utrecht Univ., Utrecht (Netherlands). Faculty of Earth Sciences

    2000-07-01

    Minerals play a key role in the environment; this role is often not well understood, because the emphasis of most environmentalists is on air, water, or the composition of solid wastes as a whole, without paying attention to their mineralogical composition. Several minerals can serve as effective and cheap adsorbents for many toxic chemicals. Several minerals can be used as a cheap substitute for expensive chemicals in environmental technologies. Environmental technologies that produce an economically interesting mineral will have an edge over competing technologies. Most of the problems, overreaction, panicky and expensive measures with regard to exposure from quartz and asbestos stem from a poor understanding of natural levels of common contaminants, a disregard for mineralogy, and a lack of insight into natural processes in general.

  6. Vitamins and Minerals

    Science.gov (United States)

    ... minerals your body needs. But if you're skipping meals, dieting, or if you're concerned that ... Kids For Parents MORE ON THIS TOPIC Healthy Breakfast Planner Nutrition & Fitness Center Vitamin D Figuring Out ...

  7. Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

    Directory of Open Access Journals (Sweden)

    A. Schlechte, R. Niewa, M. Schmidt, G. Auffermann, Yu. Prots, W. Schnelle, D. Gnida, T. Cichorek, F. Steglich and R. Kniep

    2007-01-01

    Full Text Available Ternary phases in the systems Zr–As–Se and Zr–As–Te were studied using single crystals of ZrAs1.40(1Se0.50(1 and ZrAs1.60(2Te0.40(1 (PbFCl-type of structure, space group P4/nmm as well as ZrAs0.70(1Se1.30(1 and ZrAs0.75(1Te1.25(1 (NbPS-type of structure, space group Immm. The characterization covers chemical compositions, crystal structures, homogeneity ranges and electrical resistivities. At 1223 K, the Te-containing phases can be described with the general formula ZrAsxTe2−x, with 1.53(1≤x≤1.65(1 (As-rich and 0.58(1≤x≤0.75(1 (Te-rich. Both phases are located directly on the tie-line between ZrAs2 and ZrTe2, with no indication for any deviation. Similar is true for the Se-rich phase ZrAsxSe2−x with 0.70(1≤x≤0.75(1. However, the compositional range of the respective As-rich phase ZrAsx−ySe2−x (0.03(1≤y≤0.10(1; 1.42(1≤x≤1.70(1 is not located on the tie-line ZrAs2–ZrSe2, and exhibits a triangular region of existence with intrinsic deviation of the composition towards lower non-metal contents. Except for ZrAs0.75Se1.25, from the homogeneity range of the Se-rich phase, all compounds under investigation show metallic characteristics of electrical resistivity at temperatures >20 K. Related uranium and thorium arsenide selenides display a typical magnetic field-independent rise of the resistivity towards lower temperatures, which has been explained by a non-magnetic Kondo effect. However, a similar observation has been made for ZrAs1.40Se0.50, which, among the Zr-based arsenide chalcogenides, is the only system with a large concentration of intrinsic defects in the anionic substructure.

  8. Electron-phonon coupling and structural phase transitions in early transition metal oxides and chalcogenides

    Science.gov (United States)

    Farley, Katie Elizabeth

    Pronounced nonlinear variation of electrical transport characteristics as a function of applied voltage, temperature, magnetic field, strain, or photo-excitation is usually underpinned by electronic instabilities that originate from the complex interplay of spin, orbital, and lattice degrees of freedom. This dissertation focuses on two canonical materials that show pronounced discontinuities in their temperature-dependent resistivity as a result of electron---phonon and electron---electron correlations: orthorhombic TaS3 and monoclinic VO2. Strong electron-phonon interactions in transition metal oxides and chalcogenides results in interesting structural and electronic phase transitions. The properties of the material can be changed drastically in response to external stimuli such as temperature, voltage, or light. Understanding the influence these interactions have on the electronic structure and ultimately transport characteristics is of utmost importance in order to take these materials from a fundamental aspect to prospective applications such as low-energy interconnects, steep-slope transistors, and synaptic neural networks. This dissertation describes synthetic routes to nanoscale TaS3 and VO2, develops mechanistic understanding of their electronic instabilities, and in the case of the latter system explores modulation of the electronic and structural phase transition via the incorporation of substitutional dopant atoms. We start in chapter 2 with a detailed study of the synthesis and electronic transport properties of TaS3, which undergoes a Peierls' distortion to form a charge density wave. Scaling this material down to the nanometer-sized regime allows for interrogation of single or discrete phase coherent domains. Using electrical transport and broad band noise measurements, the dynamics of pinning/depinning of the charge density wave is investigated. Chapter 3 provides a novel synthetic approach to produce high-edge-density MoS2 nanorods. MoS2 is a

  9. Chalcogenide glass mid-infrared on-chip sensor for chemical sensing

    Science.gov (United States)

    Lin, Hongtao

    Chemical sensing in the mid-infrared (mid-IR) has been considered to be significant for molecular detection for decades, but until recently has mostly relied on benchtop spectroscopic instruments like Fourier transform infrared spectrometers, etc. Recent strides in planar photonic integration envision compact, standalone "sensor-on-a-chip" devices for molecular analysis as a potentially disruptive technology as compared to their conventional bulky counterparts. However, the difficulty of achieving adequate sensitivity in integrated optical sensors is still a key barrier towards their practical application, limited by the weak interactions between photons and molecules over the short optical path length accessible on a chip. To solve the sensitivity challenge, a novel mid-IR photothermal spectroscopic sensing technique was proposed and theoretically examined. Through dramatically amplified photothermal effects in an optical nano-cavity doubly resonant at both mid-IR pump and near infrared probe wavelengths, a device design based on nested 1-D nanobeam photonic crystal cavities is numerically analyzed to demonstrate the technique's potential for single small gas molecule detection without the need for cryogenically cooled mid-IR photo-detectors. Furthermore, since silica becomes opaque at wavelengths beyond 3.5 microm, new material platforms and fabrication techniques are needed for mid-IR on-chip chemical sensors. Chalcogenide glasses (ChG), amorphous compounds containing S, Se and Te, are ideal material choices for mid-IR chemical sensors given their broad mid-IR transparency window, large photothermal figure-of-merit, amorphous structure and low processing temperature. A ChG lift-off process and a nano-fabrication technique using focused ion beam milling have been developed to fabricate mid-IR ChG resonators and photonic crystal waveguide cavities. ChG resonators on CaF2 substrate claimed a high quality factor around 4 x 105. Using these devices, we have also

  10. Structure, ionic conductivity and mobile carrier density in fast ionic conducting chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Wenlong [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M2S + (0.1 Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga2S3 + 0.9 GeS2 was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M2S + (0.1Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na2S + B2S3 (x ≤ 0.2) glasses by neutron and synchrotron x-ray diffraction

  11. 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.

  12. Mathematical model for bone mineralization

    Directory of Open Access Journals (Sweden)

    Svetlana V Komarova

    2015-08-01

    Full Text Available Defective bone mineralization has serious clinical manifestations, including deformities and fractures, but the regulation of this extracellular process is not fully understood. We have developed a mathematical model consisting of ordinary differential equations that describe collagen maturation, production and degradation of inhibitors, and mineral nucleation and growth. We examined the roles of individual processes in generating normal and abnormal mineralization patterns characterized using two outcome measures: mineralization lag time and degree of mineralization. Model parameters describing the formation of hydroxyapatite mineral on the nucleating centers most potently affected the degree of mineralization, while the parameters describing inhibitor homeostasis most effectively changed the mineralization lag time. Of interest, a parameter describing the rate of matrix maturation emerged as being capable of counter-intuitively increasing both the mineralization lag time and the degree of mineralization. We validated the accuracy of model predictions using known diseases of bone mineralization such as osteogenesis imperfecta and X-linked hypophosphatemia. The model successfully describes the highly non-linear mineralization dynamics, which includes an initial lag phase when osteoid is present but no mineralization is evident, then fast primary mineralization, followed by secondary mineralization characterized by a continuous slow increase in bone mineral content. The developed model can potentially predict the function for a mutated protein based on the histology of pathologic bone samples from mineralization disorders of unknown etiology.

  13. The mineral economy of Brazil--Economia mineral do Brasil

    Science.gov (United States)

    Gurmendi, Alfredo C.; Barboza, Frederico Lopes; Thorman, Charles H.

    1999-01-01

    This study depicts the Brazilian government structure, mineral legislation and investment policy, taxation, foreign investment policies, environmental laws and regulations, and conditions in which the mineral industry operates. The report underlines Brazil's large and diversified mineral endowment. A total of 37 mineral commodities, or groups of closely related commodities, is discussed. An overview of the geologic setting of the major mineral deposits is presented. This report is presented in English and Portuguese in pdf format.

  14. Measuring the Hardness of Minerals

    Science.gov (United States)

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  15. Extraterrestrial magnetic minerals

    Science.gov (United States)

    Pechersky, D. M.; Markov, G. P.; Tsel'movich, V. A.; Sharonova, Z. V.

    2012-07-01

    Thermomagnetic and microprobe analyses are carried out and a set of magnetic characteristics are measured for 25 meteorites and 3 tektites from the collections of the Vernadsky Geological Museum of the Russian Academy of Sciences and Museum of Natural History of the North-East Interdisciplinary Science Research Institute, Far Eastern Branch of the Russian Academy of Sciences. It is found that, notwithstanding their type, all the meteorites contain the same magnetic minerals and only differ by concentrations of these minerals. Kamacite with less than 10% nickel is the main magnetic mineral in the studied samples. Pure iron, taenite, and schreibersite are less frequent; nickel, various iron spinels, Fe-Al alloys, etc., are very rare. These minerals are normally absent in the crusts of the Earth and other planets. The studied meteorites are more likely parts of the cores and lower mantles of the meteoritic parent bodies (the planets). Uniformity in the magnetic properties of the meteorites and the types of their thermomagnetic (MT) curves is violated by secondary alterations of the meteorites in the terrestrial environment. The sediments demonstrate the same monotony as the meteorites: kamacite is likely the only extraterrestrial magnetic mineral, which is abundant in sediments and associated with cosmic dust. The compositional similarity of kamacite in iron meteorites and in cosmic dust is due to their common source; the degree of fragmentation of the material of the parent body is the only difference.

  16. KFeSbTe3: A quaternary chalcogenide aerogel for preferential adsorption of polarizable hydrocarbons and gases

    KAUST Repository

    Ahmed, Ejaz

    2015-01-01

    The first telluride-based quaternary aerogel KFeSbTe3 is synthesized by a sol-gel metathesis reaction between Fe(OAc)2 and K3SbTe3 in dimethyl formamide. The aerogel has an exceptionally large surface area 652 m2 g-1 which is amongst the highest reported for chalcogenide-based aerogels. This predominantly mesoporous material shows preferential adsorption for toluene vapors over cyclohexane or cyclopentane and CO2 over CH4 or H2. The remarkably high adsorption capacity for toluene (9.31 mmol g-1) and high selectivity for gases (CO2/H2: 121 and CO2/CH4: 75) suggest a potential use of such materials in adsorption-based separation processes for the effective purification of hydrocarbons and gases. © The Royal Society of Chemistry 2015.

  17. Wild Band Edges: The Role of Bandgap Grading and Band-Edge Fluctuations in High-Efficiency Chalcogenide Devices

    Energy Technology Data Exchange (ETDEWEB)

    Repins, Ingrid; Mansfield, Lorelle; Kanevce, Ana; Jensen, Soren A.; Kuciauskas, Darius; Glynn, Stephen; Barnes, Teresa; Metzger, Wyatt; Burst, James; Jiang, Chun-Sheng; Dippo, Patricia; Harvey, Steve; Teeter, Glenn; Perkins, Craig; Egaas, Brian; Zakutayev, Andriy; Alsmeier, J.-H.; Lussky, T.; Korte, L.; Wilks, R. G.; Bar, M.; Yan, Y.; Lany, Stephan; Zawadzki, Pawel; Park, Ji-Sang; Wei, Suhuai

    2016-11-21

    Band-edge effects - including grading, electrostatic fluctuations, bandgap fluctuations, and band tails - affect chalcogenide device efficiency. These effects now require more careful consideration as efficiencies increase beyond 20%. Several aspects of the relationships between band-edge phenomena and device performance for NREL absorbers are examined. For Cu(In, Ga)Se2 devices, recent increases in diffusion length imply changes to the optimum bandgap profile. The origin, impact, and modification of electrostatic and bandgap fluctuations are also discussed. The application of the same principles to devices based on CdTe, kesterites, and emerging absorbers (Cu2SnS3, CuSbS2), considering differences in materials properties, is examined.

  18. Lead-chalcogenide mid-infrared vertical external cavity surface emitting lasers with improved threshold: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fill, Matthias [ETH Zurich, Laser Spectroscopy and Sensing Lab, 8093 Zurich (Switzerland); Phocone AG, 8005 Zurich (Switzerland); Debernardi, Pierluigi [IEIIT-CNR, Torino 10129 (Italy); Felder, Ferdinand [Phocone AG, 8005 Zurich (Switzerland); Zogg, Hans [ETH Zurich (Switzerland)

    2013-11-11

    Mid-infrared Vertical External Cavity Surface Emitting Lasers (VECSEL) based on narrow gap lead-chalcogenide (IV-VI) semiconductors exhibit strongly reduced threshold powers if the active layers are structured laterally for improved optical confinement. This is predicted by 3-d optical calculations; they show that lateral optical confinement is needed to counteract the anti-guiding features of IV-VIs due to their negative temperature dependence of the refractive index. An experimental proof is performed with PbSe quantum well based VECSEL grown on a Si-substrate by molecular beam epitaxy and emitting around 3.3 μm. With proper mesa-etching, the threshold intensity is about 8-times reduced.

  19. Wild Band Edges: The Role of Bandgap Grading and Band-Edge Fluctuations in High-Efficiency Chalcogenide Devices: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Repins, Ingrid; Mansfield, Lorelle; Kanevce, Ana; Jensen, Soren A.; Kuciauskas, Darius; Glynn, Stephen; Barnes, Teresa; Metzger, Wyatt; Burst, James; Jiang, Chun-Sheng; Dippo, Patricia; Harvey, Steve; Teeter, Glenn; Perkins, Craig; Egaas, Brian; Zakutayev, Andriy; Alsmeier, J.-H.; Lussky, T.; Korte, L.; Wilks, R. G.; Bar, M.; Yan, Y.; Lany, Stephan; Zawadzki, Pawel; Park, Ji-Sang; Wei, Suhuai

    2016-06-16

    Band-edge effects -- including grading, electrostatic fluctuations, bandgap fluctuations, and band tails -- affect chalcogenide device efficiency. These effects now require more careful consideration as efficiencies increase beyond 20%. Several aspects of the relationships between band-edge phenomena and device performance for NREL absorbers are examined. For Cu(In,Ga)Se2 devices, recent increases in diffusion length imply changes to optimum bandgap profile. The origin, impact, and modification of electrostatic and bandgap fluctuations are also discussed. The application of the same principles to devices based on CdTe, kesterites, and emerging absorbers (Cu2SnS3, CuSbS2), considering differences in materials properties and defect formation energies, is examined.

  20. Extended free-volume defects in chalcogenide glassy semiconductors induced by high-energy {gamma}-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, Valentina [Lviv Institute of Materials of SRC (Ukraine); State University of Vital Activity Safety, Lviv 79007 (Ukraine); Filipecki, Jacek; Shpotyuk, Oleh [Institute of Physics, Jan Dlugosz University, Czestochowa (Poland)

    2009-08-15

    It was shown that under-coordinated topological defects induced by high-energy {gamma}-irradiation can be a reason for significant changes in positron annihilation lifetime spectra of multicomponent chalcogenide glassy semiconductors within ternary Ge-As(Sb)-S systems. In the case of negatively-charged sulphur and arsenic atoms, the excess of free volume is quite enough to produce additional input in the second defect-related channel of positron trapping, while under-coordinated germanium atoms are practically non-detectable with this technique because of low associated free volume. Despite radiation-induced densification, the average positron lifetime demonstrate both growing and decaying tendencies after {gamma}-irradiation depending on glass composition. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Characterization of the optical constants and dispersion parameters of chalcogenide Te40Se30S30 thin film: thickness effect

    Science.gov (United States)

    Abd-Elrahman, M. I.; Hafiz, M. M.; Qasem, Ammar; Abdel-Rahim, M. A.

    2016-02-01

    Chalcogenide Te40Se30S30 thin films of different thickness (100-450 nm) are prepared by thermal evaporation of the Te40Se30S30 bulk. X-ray examination of the film shows some prominent peaks relate to crystalline phases indicating the crystallization process. The calculated particles of crystals from the X-ray diffraction peaks are found to be from 11 to 26 nm. As the thickness increases, the transmittance decreases and the reflectance increases. This could be attributed to the increment of the absorption of photons as more states will be available for absorbance in the case of thicker films. The decrease in the direct band gap with thickness is accompanied with an increase in energy of localized states. The obtained data for the refractive index could be fit to the dispersion model based on the single oscillator equation. The single-oscillator energy decreases, while the dispersion energy increases as the thickness increases.

  2. Experimental versus expected halide-ion size differences; structural changes in three series of isotypic bismuth chalcogenide halides.

    Science.gov (United States)

    Keller, Egbert; Krämer, Volker

    2006-06-01

    Experimentally determined halide-ion size differences are compared with expected size differences in the three series of isotypic bismuth chalcogenide halide compounds, KBi(6)O(9)X (X = Cl, Br and I), BiOX (X = F, Cl, Br and I) and BiSX (X = Cl, Br and I). The strong deviations observed can be assigned to steric strain caused by the heterogeneity of the bond-valence pattern and (for BiOX) to anion-anion repulsion and a change in the connectivity scheme. Some special features of the BiOF structure and the question of "isotypism" within the BiOX series are briefly discussed. Structural changes within the BiSX series are analysed.

  3. A Tapered Chalcogenide Microstructured Optical Fiber for Mid-IR Parabolic Pulse Generation: Design and Performance Study

    CERN Document Server

    Barh, Ajanta; Varshney, Ravi K; Pal, Bishnu P

    2013-01-01

    This paper presents a theoretical design of chalcogenide glass based tapered microstructured optical fiber (MOF) to generate high power parabolic pulses (PPs) at the mid-IR wavelength (~ 2 {\\mu}m). We optimize fiber cross-section by the multipole method and studied pulse evolution by well known Symmetrized Split-Step Fourier Method. Our numerical investigation reveals the possibility of highly efficient PP generation within a very short length (~ 18 cm) of this MOF for a Gaussian input pulse of 60 W peak power and FWHM of 3.5 ps. We examined quality of the generated PP by calculating the misfit parameter including the third order dispersion and fiber loss. Further, the effects of variations in input pulse power, pulse width and pulse energy on generated PP were also studied.

  4. Temperature dependence of magnetic anisotropy constant in iron chalcogenide Fe3Se4: Excellent agreement with theories

    Science.gov (United States)

    Wang, Jun; Duan, Hongyan; Lin, Xiong; Aguilar, Victor; Mosqueda, Aaron; Zhao, Guo-meng

    2012-01-01

    Magnetic hysteresis loops were measured for ferrimagnetic iron chalcogenide Fe3Se4 nanoparticles in the whole temperature range below the Curie temperature TC (315 K). The coercivity of the material is huge, reaching about 40 kOe at 10 K. The magnetic anisotropy constant K was determined from the magnetic hysteresis loop using the law of approach to saturation. The deduced anisotropy constant at 10 K is 5.22×106 erg/cm3, which is over one order of magnitude larger than that of Fe3O4. We also demonstrated that the experimental magnetic hysteresis loop is in good agreement with the theoretical curve calculated by Stoner and Wohlfarth for a noninteracting randomly oriented uniaxial single-domain particle system. Moreover, we show that K is proportional to the cube of the saturation magnetization Ms, which confirms earlier theoretical models for uniaxial magnets. PMID:23258940

  5. Temperature dependence of magnetic anisotropy constant in iron chalcogenide Fe(3)Se(4): Excellent agreement with theories.

    Science.gov (United States)

    Wang, Jun; Duan, Hongyan; Lin, Xiong; Aguilar, Victor; Mosqueda, Aaron; Zhao, Guo-Meng

    2012-11-15

    Magnetic hysteresis loops were measured for ferrimagnetic iron chalcogenide [Formula: see text] nanoparticles in the whole temperature range below the Curie temperature [Formula: see text] (315 K). The coercivity of the material is huge, reaching about 40 kOe at 10 K. The magnetic anisotropy constant K was determined from the magnetic hysteresis loop using the law of approach to saturation. The deduced anisotropy constant at 10 K is [Formula: see text], which is over one order of magnitude larger than that of [Formula: see text]. We also demonstrated that the experimental magnetic hysteresis loop is in good agreement with the theoretical curve calculated by Stoner and Wohlfarth for a noninteracting randomly oriented uniaxial single-domain particle system. Moreover, we show that K is proportional to the cube of the saturation magnetization [Formula: see text], which confirms earlier theoretical models for uniaxial magnets.

  6. The effects of porosity on optical properties of semiconductor chalcogenide films obtained by the chemical bath deposition.

    Science.gov (United States)

    Vorobiev, Yuri V; Horley, Paul P; Hernández-Borja, Jorge; Esparza-Ponce, Hilda E; Ramírez-Bon, Rafael; Vorobiev, Pavel; Pérez, Claudia; González-Hernández, Jesús

    2012-08-29

    This paper is dedicated to study the thin polycrystalline films of semiconductor chalcogenide materials (CdS, CdSe, and PbS) obtained by ammonia-free chemical bath deposition. The obtained material is of polycrystalline nature with crystallite of a size that, from a general point of view, should not result in any noticeable quantum confinement. Nevertheless, we were able to observe blueshift of the fundamental absorption edge and reduced refractive index in comparison with the corresponding bulk materials. Both effects are attributed to the material porosity which is a typical feature of chemical bath deposition technique. The blueshift is caused by quantum confinement in pores, whereas the refractive index variation is the evident result of the density reduction. Quantum mechanical description of the nanopores in semiconductor is given based on the application of even mirror boundary conditions for the solution of the Schrödinger equation; the results of calculations give a reasonable explanation of the experimental data.

  7. Thorium in mineral products.

    Science.gov (United States)

    Collier, D E; Brown, S A; Blagojevic, N; Soldenhoff, K H; Ring, R J

    2001-01-01

    Many ores contain low levels of thorium. When these ores are processed, the associated radioactivity can be found in mineral concentrates, intermediates and final products. There is an incentive for industries to remove radioactivity from mineral products to allow the movement and sale of these materials, both nationally and internationally, without the need for licensing. Control of thorium in various products involves the development and optimisation of process steps to be able to meet product specifications. The Australian Nuclear Science and Technology Organisation (ANSTO) has undertaken a range of R & D programmes targeting the treatment of thorium-bearing minerals. This paper discusses the application of a microprobe technique for siting radioactivity in zircon and ilmenite and the problems experienced in measuring the concentrations in solid rare earth products.

  8. High-precision measurements of the compressibility of chalcogenide glasses at a hydrostatic pressure up to 9 GPa

    Science.gov (United States)

    Brazhkin, V. V.; Bychkov, E.; Tsiok, O. B.

    2016-08-01

    The volumes of glassy germanium chalcogenides GeSe2, GeS2, Ge17Se83, and Ge8Se92 are precisely measured at a hydrostatic pressure up to 8.5 GPa. The stoichiometric GeSe2 and GeS2 glasses exhibit elastic behavior in the pressure range up to 3 GPa, and their bulk modulus decreases at pressures higher than 2-2.5 GPa. At higher pressures, inelastic relaxation processes begin and their intensity is proportional to the logarithm of time. The relaxation rate for the GeSe2 glasses has a pronounced maximum at 3.5-4.5 GPa, which indicates the existence of several parallel structural transformation mechanisms. The nonstoichiometric glasses exhibit a diffuse transformation and inelastic behavior at pressures above 1-2 GPa. The maximum relaxation rate in these glasses is significantly lower than that in the stoichiometric GeSe2 glasses. All glasses are characterized by the "loss of memory" of history: after relaxation at a fixed pressure, the further increase in the pressure returns the volume to the compression curve obtained without a stop for relaxation. After pressure release, the residual densification in the stoichiometric glasses is about 7% and that in the Ge17Se83 glasses is 1.5%. The volume of the Ge8Se92 glass returns to its initial value within the limits of experimental error. As the pressure decreases, the effective bulk moduli of the Ge17Se83 and Ge8Se92 glasses coincide with the moduli after isobaric relaxation at the stage of increasing pressure, and the bulk modulus of the stoichiometric GeSe2 glass upon decreasing pressure noticeably exceeds the bulk modulus after isobaric relaxation at the stage of increasing pressure. Along with the reported data, our results can be used to draw conclusions regarding the diffuse transformations in glassy germanium chalcogenides during compression.

  9. Synthesis and solid state structures of Chalcogenide compounds of Imidazolin-2-ylidene-1,1-Diphenyl-phosphinamine

    Indian Academy of Sciences (India)

    Naktode Kishor; Suman Das; Abhinanda Kundu; Hari Pada Nayek; Tarun K Panda

    2016-03-01

    We report the synthesis and solid state structures of 1,3-di-aryl-imidazolin-2-ylidine-1,1-diphenylphosphinamine [(aryl=mesityl (1a) and aryl=2,6-diisopripyl (1b)] and their chalcogenide compounds 3-di-aryl-imidazolin-2-ylidine-P, P-diphenylphosphinicamide (2a,b), 1,3-di-aryl-imidazolin-2-ylidine-P,P diphenyl-phosphinothioicamide (3a,b) and 1,3-diaryl-imidazolin-2-ylidine-P,P -diphenyl-phosphinoselenoicamide (4a,b).The compounds 1a,b were prepared in good yield by the reaction of 1,3-di-aryl-imidazolin-2-imine and chlorodiphenylphosphine in the presence of triethylamine in toluene. The reactions of 1a,b with elemental sulphur and selenium afforded the corresponding chalcogenide compounds 3a,b and 4a,b respectively.The corresponding oxo- derivative (2a,b) was obtained by reacting compound 1a,b with 30% aqueous hydrogen peroxide in THF. The molecular structures of 1a, 2a, 3a and 4a,b have been established by single crystal X-ray diffraction analyses. The molecular structures reveal that even C1–N1–P1 angle (124.62o) in compound 1a is less obtuse compared to the corresponding C1–N1–Si1 angles (157.8o) observed in related N-silylated 2-iminoimidazolines and trimethylsilyl iminophosphoranes. C1–N1–P1 angles are further widened in compounds 2a, 3a, and 4a,b due to the attachment of chalcogen atoms onto phosphorus atom.

  10. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  11. Bioleaching of Minerals

    Energy Technology Data Exchange (ETDEWEB)

    F. Roberto

    2002-02-01

    Bioleaching is the term used to describe the microbial dissolution of metals from minerals. The commercial bioleaching of metals, particularly those hosted in sulfide minerals, is supported by the technical disciplines of biohydrometallurgy, hydrometallurgy, pyrometallurgy, chemistry, electrochemistry, and chemical engineering. The study of the natural weathering of these same minerals, above and below ground, is also linked to the fields of geomicrobiology and biogeochemistry. Studies of abandoned and disused mines indicate that the alterations of the natural environment due to man's activities leave as remnants microbiological activity that continues the biologically mediated release of metals from the host rock (acid rock drainage; ARD). A significant fraction of the world's copper, gold and uranium is now recovered by exploiting native or introduced microbial communities. While some members of these unique communities have been extensively studied for the past 50 years, our knowledge of the composition of these communities, and the function of the individual species present remains relatively limited. Nevertheless, bioleaching represents a major strategy in mineral resource recovery whose importance will increase as ore reserves decline in quality, become more difficult to process (due to increased depth, increased need for comminution, for example), and as environmental considerations eliminate traditional physical processes such as smelting, which have served the mining industry for hundreds of years.

  12. Mixtures and mineral reactions

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, S.; Ganguly, J.

    1987-01-01

    Considerable progress has been made in our understanding of the physicochemical evolution of natural rocks through systematic analysis of the compositional properties and phase relations of their mineral assemblages. This book brings together concepts of classical thermodynamics, solution models, and atomic ordering and interactions that constitute a basis of such analysis, with examples of application to subsolidus petrological problems.

  13. Clay Mineral: Radiological Characterization

    Science.gov (United States)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  14. Mineralization of fossil wood

    NARCIS (Netherlands)

    Buurman, P.

    1972-01-01

    Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points t

  15. A structural study of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 at high pressure

    CERN Document Server

    Kozlenko, D P; Hull, S; Knorr, K; Savenko, B N; Shchennikov, V V; Voronin, V I

    2002-01-01

    The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of the Landau theory of phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e sub 4. This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides

  16. Mid-infrared supercontinuum generation in a three-hole Ge20Sb15Se65 chalcogenide suspended-core fiber

    Science.gov (United States)

    Han, Xin; You, Chenyang; Dai, Shixun; Zhang, Peiqing; Wang, Yingying; Guo, Fangxia; Xu, Dong; Luo, Baohua; Xu, Peipeng; Wang, Xunsi

    2017-03-01

    This work experimentally demonstrates the supercontinuum (SC) generation in a three-hole arsenic free Ge20Sb15Se65 chalcogenide suspended-core fiber. Mechanical drilling was used to prepare the chalcogenide glass preform, which was drawn into suspended-core fibers. The zero-dispersion wavelength of the fiber is moved toward the shorter wavelength of about 3.2 μm through changing the fiber core diameter by controlling the pressure of inert gas during fiber drawing. When a 15 cm-long fiber with a core diameter of 6 μm is pumped using 150 fs pulses at 3.3 μm, SC spanning from ∼3 μm to ∼8 μm was generated.

  17. Universal behavior of chalcogenides of rare-earth metals in the transition to a state with intermediate valence at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Tsiok, O. B.; Khvostantsev, L. G.; Brazhkin, V. V., E-mail: brazhkin@hppi.troitsk.ru [Russian Academy of Sciences, Vereshchagin Institute of High-Pressure Physics (Russian Federation)

    2015-06-15

    Precision measurements of resistivity, thermopower, and volume are performed for TmS, TmSe, and TmTe under a hydrostatic pressure up to 8 GPa. Comparison of the transport properties and volume of TmTe and SmTe in the valence transition region demonstrates a complete analogy up to quantitative coincidence. It is shown that the thermopower of all thulium and samarium chalcogenides in the lattice collapse region and in subsequent rearrangement of the electron spectrum in a wide range of pressures follow a universal dependence corresponding the passage of the Fermi level through the peak of the density of states (DOS). The results are considered in the context of ideas about the exciton nature of the intermediate valence in chalcogenides of rare-earth metals.

  18. Aggregate and Mineral Resources - Industrial Mineral Mining Operations

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — An Industrial Mineral Mining Operation is a DEP primary facility type related to the Industrial Mineral Mining Program. The sub-facility types are listed below:Deep...

  19. Carbon Mineral Ecology: Predicting the Undiscovered Minerals of Carbon

    Science.gov (United States)

    Hazen, R. M.; Hummer, D. R.; Downs, R. T.; Hystad, G.; Golden, J.

    2015-12-01

    The diversity and distribution of Earth's minerals through deep time reflects key events in our planet's crustal evolution. Studies in mineral ecology exploit mineralogical databases to document diversity-distribution relationships of minerals, which reveal that all carbon-bearing minerals, as well as subsets containing C with O, H, Ca, or Na, conform to Large Number of Rare Events (LNRE) distributions. LNRE models facilitate prediction of total mineral diversity, and thus point to minerals that exist on Earth but have not yet been discovered and described. Our model predicts that at least 548 C minerals exist on Earth today, indicating that at least 145 carbon-bearing mineral species have yet to be discovered. Furthermore, by analyzing subsets of the most common additional elements in carbon-bearing minerals (i.e., 378 C + O species; 282 C + H species; 133 C + Ca species; and 100 C + Na species), we predict that 129 of these missing carbon minerals contain oxygen, 118 contain hydrogen, 52 contain calcium, and more than 60 contain sodium. The majority of these as yet undescribed minerals are predicted to be hydrous carbonates, many of which may have been overlooked because they are colorless, poorly crystalized, and/or water-soluble. We propose the identities of plausible as yet undescribed carbon minerals, as well as search strategies for their discovery. Some of these minerals will be natural examples of known synthetic compounds, including carbides such as calcium carbide (CaC2), crystalline hydrocarbons such as pyrene (C16H10), and numerous oxalates, anhydrous carbonates, and hydrous carbonates. Many other missing carbon minerals will be isomorphs of known carbon minerals, notably of the more than 100 different hydrous carbonate structures. An understanding of Earth's "missing" minerals provides a more complete picture of geochemical processes that influence crustal evolution.

  20. Mineral processing of heavy mineral sands from Malawi and Malaysia

    OpenAIRE

    Mitchell, C J

    1992-01-01

    Processing of heavy mineral sands involves many techniques including gravity, magnetic and electrostatic separation. As part of a laboratory programme to develop effective mineral processing techniques, two mineral sands from Malawi and Malaysia were processed using the standard techniques, with emphasis placed on the Carpco electrostatic separator. These sands were initially characterised mineralogically by scanning electron microscopy (SEM), electron microprobe analysis (EPMA...

  1. Adsorption of RNA on mineral surfaces and mineral precipitates

    Science.gov (United States)

    Biondi, Elisa; Furukawa, Yoshihiro; Kawai, Jun

    2017-01-01

    The prebiotic significance of laboratory experiments that study the interactions between oligomeric RNA and mineral species is difficult to know. Natural exemplars of specific minerals can differ widely depending on their provenance. While laboratory-generated samples of synthetic minerals can have controlled compositions, they are often viewed as "unnatural". Here, we show how trends in the interaction of RNA with natural mineral specimens, synthetic mineral specimens, and co-precipitated pairs of synthetic minerals, can make a persuasive case that the observed interactions reflect the composition of the minerals themselves, rather than their being simply examples of large molecules associating nonspecifically with large surfaces. Using this approach, we have discovered Periodic Table trends in the binding of oligomeric RNA to alkaline earth carbonate minerals and alkaline earth sulfate minerals, where those trends are the same when measured in natural and synthetic minerals. They are also validated by comparison of co-precipitated synthetic minerals. We also show differential binding of RNA to polymorphic forms of calcium carbonate, and the stabilization of bound RNA on aragonite. These have relevance to the prebiotic stabilization of RNA, where such carbonate minerals are expected to have been abundant, as they appear to be today on Mars.

  2. Thulium pumped mid-infrared 0.9-9μm supercontinuum generation in concatenated fluoride and chalcogenide glass fibers.

    Science.gov (United States)

    Kubat, Irnis; Petersen, Christian Rosenberg; Møller, Uffe Visbech; Seddon, Angela; Benson, Trevor; Brilland, Laurent; Méchin, David; Moselund, Peter M; Bang, Ole

    2014-02-24

    We theoretically demonstrate a novel approach for generating Mid-InfraRed SuperContinuum (MIR SC) by using concatenated fluoride and chalcogenide glass fibers pumped with a standard pulsed Thulium (Tm) laser (T(FWHM)=3.5ps, P0=20kW, ν(R)=30MHz, and P(avg)=2W). The fluoride fiber SC is generated in 10m of ZBLAN spanning the 0.9-4.1μm SC at the -30dB level. The ZBLAN fiber SC is then coupled into 10cm of As2Se3 chalcogenide Microstructured Optical Fiber (MOF) designed to have a zero-dispersion wavelength (λ(ZDW)) significantly below the 4.1μm InfraRed (IR) edge of the ZBLAN fiber SC, here 3.55μm. This allows the MIR solitons in the ZBLAN fiber SC to couple into anomalous dispersion in the chalcogenide fiber and further redshift out to the fiber loss edge at around 9μm. The final 0.9-9μm SC covers over 3 octaves in the MIR with around 15mW of power converted into the 6-9μm range.

  3. Single step preparation of quaternary Cu2ZnSnSe4 thin films by RF magnetron sputtering from binary chalcogenide targets

    Science.gov (United States)

    Wibowo, Rachmat Adhi; Kim, Woo Seok; Lee, Eun Soo; Munir, Badrul; Kim, Kyoo Ho

    2007-10-01

    Cu2ZnSnSe4 (CZTSe) thin films were grown in a single step procedure by RF magnetron sputtering from a compacted powder consisting of blended chalcogenides. Targets with various chalcogenide mole ratios were designed for the purpose of preparing stoichiometric as-grown films. The material concentrations of the films grown at room temperature were found to depend on the mole ratio of the chalcogenides in the targets. It was found that a significant deviation of material concentration of the films from ideal stoichiometry led to the formation of CuSe, ZnSe and SnSe secondary phases. CZTSe films with a stannite phase could be grown even at room temperature from the sputtering target containing Cu2Se with corresponding growth orientations of (101), (112), (220/204), (312/116) and (332/316). The p-type CZTSe film grown at a substrate temperature of 150C showed a high absorption coefficient of 10cm with an optical band gap of 1.56 eV, resistivity as low as 1.482Ωcm and carrier concentration of 1×10cm. These results suggested that the control of the target compositions was crucial to grow single phase and stoichiometric quaternary CZTSe films.

  4. Oxygen Extraction from Minerals

    Science.gov (United States)

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  5. Agricultural Minerals Operations - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer includes agricultural minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  6. Construction Minerals Operations - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  7. Discussion on Nontraditional Mineral Resources

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the authors introduce the concept of nontraditional mineral resources, and pro pose the major system of nontraditional mineral resources, including nontraditional resources, research methods, mining and mineral economics. Then the authors conclude that the research on nontraditional mineral resources is not only significant to satisfication the human needs in the 21st century, but also important to the development of the present geological theory.

  8. Aggregates from mineral wastes

    Directory of Open Access Journals (Sweden)

    Baic Ireneusz

    2016-01-01

    Full Text Available The problem concerning the growing demand for natural aggregates and the need to limit costs, including transportation from remote deposits, cause the increase in growth of interest in aggregates from mineral wastes as well as in technologies of their production and recovery. The paper presents the issue related to the group of aggregates other than natural. A common name is proposed for such material: “alternative aggregates”. The name seems to be fully justified due to adequacy of this term because of this raw materials origin and role, in comparison to the meaning of natural aggregates based on gravel and sand as well as crushed stones. The paper presents characteristics of the market and basic application of aggregates produced from mineral wastes, generated in the mining, power and metallurgical industries as well as material from demolished objects.

  9. Rock and mineral magnetism

    CERN Document Server

    O’Reilly, W

    1984-01-01

    The past two decades have witnessed a revolution in the earth sciences. The quantitative, instrument-based measurements and physical models of. geophysics, together with advances in technology, have radically transformed the way in which the Earth, and especially its crust, is described. The study of the magnetism of the rocks of the Earth's crust has played a major part in this transformation. Rocks, or more specifically their constituent magnetic minerals, can be regarded as a measuring instrument provided by nature, which can be employed in the service of the earth sciences. Thus magnetic minerals are a recording magnetometer; a goniometer or protractor, recording the directions of flows, fields and forces; a clock; a recording thermometer; a position recorder; astrain gauge; an instrument for geo­ logical surveying; a tracer in climatology and hydrology; a tool in petrology. No instrument is linear, or free from noise and systematic errors, and the performance of nature's instrument must be assessed and ...

  10. Iodine mineral waters

    Directory of Open Access Journals (Sweden)

    Iluta Alexandru

    2011-11-01

    Full Text Available Iodine mineral waters are found especially in sub-Carpathian region, also in regions with Salif deposits. Waters are currently used iodine in drinking cure for chaps and Basedow. Are also indicated in balneology. Iodine water containing at least 1 mg L, there is pure iodine is usually given the nature of other types of mineral waters further: sodium chlorinated water (Bazna (50-70 mg iodine / l, Baile Govora (50 - 70 mg / l, Bălţăteşti (4-5 mg / l, salted Monteoru (30 mg / l, mine water mixed alkaline chlorination, sulphate, which are indicated for crenoterapie (hypo or isotonic to the bathrooms Olăneşti or Călimăneşti-Căciulata.

  11. Coastal placer minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Gujar, A.R.

    be covered with shelly or quartz-rich sand. Transport of eroded materials by glaciers occurs in high latitude and snow bound regions. BERM Selective Sorting BERM SCIENCE REPORTER, OCTOBER 201445 and efforts spent and the market value of the metal... was the main global supplier of ilmenite. In 1950, the Department of Atomic Energy established the Indian Rare Earths Limited (IREL), a public sector undertaking at Alwaye, Kochi (Kerala). Mining and separation of heavy minerals commenced in 1965...

  12. Mineral metabolism in cats

    OpenAIRE

    Pineda Martos, Carmen María

    2014-01-01

    The present Doctoral Thesis wa metabolism in the feline species. Through a series of studies, the relationship between calcium metabolism and the main hormones involved in it has been determined metabolism during the juvenile stage of growing cats effects linked to feeding calculolytic diets on feline mineral metabolism. The first part of the work was aimed the quantification of intact (I-PTH) and whole PTH) and to characterize the dynamics of PTH secretion, including ...

  13. Refractory Minerals in Henan Province

    Institute of Scientific and Technical Information of China (English)

    JIN Qinguo; LI Jing; LIU Jiehua; LIU Yanjun

    2004-01-01

    Henan province is very rich in refractory minerals of many varieties including silica, dolomite, graphite,pearlite, sepiolite, olivine, and sillimanite group minerals, besides the abundant reserves of fireclay and bauxite,which lay a good foundation for the development of the refractories industry of the province. The paper introduces the reserves, distribution and character of the refractory minerals in Henan province.

  14. Definitions of Health Terms: Minerals

    Science.gov (United States)

    ... this page: https://medlineplus.gov/definitions/mineralsdefinitions.html Definitions of Health Terms : Minerals To use the sharing features on ... of the minerals that you need. Find more definitions on Fitness | General Health | Minerals | Nutrition | Vitamins Antioxidants Antioxidants are substances that ...

  15. Polymer-mediated mesoscale mineralization

    Institute of Scientific and Technical Information of China (English)

    CHEN ShaoFeng; YU ShuHong

    2009-01-01

    Polymer-controlled mineralization in aqueous solution or in a mixed solvent media, as well as its com-bination with the interface of air-water can lead to the formation of minerals with unique structures and morphologies, which sheds light on the possibility to mimic the detailed structures of the natural min-erals.

  16. Culture systems: mineral oil overlay.

    Science.gov (United States)

    Morbeck, Dean E; Leonard, Phoebe H

    2012-01-01

    Mineral oil overlay microdrop is commonly used during in vitro fertilization (IVF) procedures. Though mineral oil appears homogeneous, it is an undefined product that can vary in quality. Here, we describe the history, chemistry, processing, and optimal use of mineral oil for IVF and embryo culture.

  17. RELATIVE TRACE MINERAL BIOAVAILABILITY

    Directory of Open Access Journals (Sweden)

    Rchard D. Miles

    2006-10-01

    Full Text Available Para determinar a eficiência de utilização de elementos minerais dietéticos, deve-se conhecer a biodisponibilidade relativa de cada elemento de um determinado ingrediente ou de uma ração completa. Análises químicas da dieta ou de um determinado ingrediente não indicam a efetividade biológica de um nutriente. Existem muitos fatores que influenciam a biodisponibilidade dos minerais, especialmente dos minerais-traço, tais como: nível de consumo do mineral, forma química, digestibilidade da dieta, tamanho da partícula, interações com outros minerais e nutrientes, agentes quelantes, inibidores, estado fisiológico do animal, qualidade da água, condições de processamento ao qual ingredientes individuais ou uma dieta completa foram expostos e, é óbvio, a idade e a espécie animal. Quando um mineral-traço é ingerido, sua biodisponibilidade é influenciada por propriedades específicas do mineral da maneira como está incluído na dieta. Por exemplo, sua valência e forma molecular (orgânica versus inorgânica são importantes. Por causa dessas propriedades específicas, o mineral pode formar complexos com outros componentes no intestino, o que pode dificultar ou facilitar a absorção pela mucosa, o transporte ou o metabolismo do mineral no organismo. É bem conhecido que certos minerais em sua forma inorgânica competem com outros minerais por sítios de ligação e por absorção no intestino. O conhecimento sobre a biodisponibilidade dos minerais-traço nos ingredientes e fontes suplementares é importante para a formulação econômica de uma ração para garantir ótimo desempenho animal. A biodisponibilidade deve ser entendida como um valor “estimado” que reflete a absorção e a utilização do mineral sobre condições de um experimento específico e não de uma propriedade inerente e específica de um ingrediente ou suplemento de ração. Com a tecnologia disponível, a determinação da biodisponibilidade dentro de

  18. Water, mineral waters and health.

    Science.gov (United States)

    Petraccia, Luisa; Liberati, Giovanna; Masciullo, Stefano Giuseppe; Grassi, Marcello; Fraioli, Antonio

    2006-06-01

    The authors focus on water resources and the use of mineral waters in human nutrition, especially in the different stages of life, in physical activity and in the presence of some morbid conditions. Mineral water is characterized by its purity at source, its content in minerals, trace elements and other constituents, its conservation and its healing properties recognized by the Ministry of Health after clinical and pharmacological trials. Based on total salt content in grams after evaporation of 1l mineral water dried at 180 degrees C (dry residues), mineral waters can be classified as: waters with a very low mineral content, waters low in mineral content, waters with a medium mineral content, and strongly mineralized waters. Based on ion composition mineral waters can be classified as: bicarbonate waters, sulfate waters, sodium chloride or saltwater, sulfuric waters. Based on biological activity mineral waters can be classified as: diuretic waters, cathartic waters, waters with antiphlogistic properties. Instructions for use, doses, and current regulations are included.

  19. Reinforcing the mineral layer

    Energy Technology Data Exchange (ETDEWEB)

    Pishchulin, V.V.; Kuntsevich, V.I.; Seryy, A.M.; Shirokov, A.P.

    1980-05-15

    A way of reinforcing the mineral layer includes drilling holes and putting in anchors that are longer than the width of the layer strip being extracted. It also includes shortening the anchors as the strip is mined and reinforcing the remaining part of the anchor in the mouth of the hole. To increase the productivity and safety of the work, the anchors are shortened by cutting them as the strip is mined and are reinforced through wedging. The device for doing this has auxilliary lengthwise grooves in the shaft located along its length at an interval equal to the width of the band being extracted.

  20. Mineral mining installation

    Energy Technology Data Exchange (ETDEWEB)

    Plevak, L.; Weirich, W.

    1982-04-20

    A longwall mineral mining installation has a longwall conveyor and a plurality of roof support units positioned side-by-side at the goaf side of the conveyor. The hydraulic appliances of the roof support units, such as their hydraulic props, hydraulic advance rams and hydraulic control valves, are supplied with pressurized hydraulic fluid from hydraulic supply lines which run along the goaf side of the conveyor. A plurality of flat, platelike intermediate members are provided at the goaf side of the conveyor. These intermediate members are formed with internal ducts for feeding the hydraulic fluid from the supply lines to the hydraulic appliances of the roof support units.

  1. Strategic Minerals of India

    Directory of Open Access Journals (Sweden)

    D. N. Wadia

    1952-09-01

    Full Text Available The state of disequilibrium in the country's mineral economy may not be harmful in time of international peace, but is a source of double danger to national security in a war emergency, when imports of essential commodities, e.g., petroleum may be jeopardised and the off-take of credit earning exports may be stopped. A healthy economy can be achieved by balancing as near as possible, the surpluses against deficits through building up civilian industrial power of production of substitute for some deficient and sub-marginal commodities and stockpiling of others.

  2. Solution-based synthesis and design of late transition metal chalcogenide materials for oxygen reduction reaction (ORR).

    Science.gov (United States)

    Gao, Min-Rui; Jiang, Jun; Yu, Shu-Hong

    2012-01-09

    Late transition metal chalcogenide (LTMC) nanomaterials have been introduced as a promising Pt-free oxygen reduction reaction (ORR) electrocatalysts because of their low cost, good ORR activity, high methanol tolerance, and facile synthesis. Herein, an overview on the design and synthesis of LTMC nanomaterials by solution-based strategies is presented along with their ORR performances. Current solution-based synthetic approaches towards LTMC nanomaterials include a hydrothermal/solvothermal approach, single-source precursor approach, hot-injection approach, template-directed soft synthesis, and Kirkendall-effect-induced soft synthesis. Although the ORR activity and stability of LTMC nanomaterials are still far from what is needed for practical fuel-cell applications, much enhanced electrocatalytic performance can be expected. Recent advances have emphasized that decorating the surface of the LTMC nanostructures with other functional nanoparticles can lead to much better ORR catalytic activity. It is believed that new synthesis approaches to LTMCs, modification techniques of LTMCs, and LTMCs with desirable morphology, size, composition, and structures are expected to be developed in the future to satisfy the requirements of commercial fuel cells.

  3. Optical characterization of thermally evaporated thin films of As40S40Se20 chalcogenide glass by reflectance measurements

    Science.gov (United States)

    Márquez, E.; González-Leal, J. M.; Prieto-Alcón, R.; Vlcek, M.; Stronski, A.; Wagner, T.; Minkov, D.

    Optical reflection spectra, at normal incidence, of ternary chalcogenide thin films of chemical composition As40S40Se20, deposited by thermal evaporation, were obtained in the 400 nm to 2200 nm spectral region. The optical constants of this amorphous material were computed using an optical characterization method based mainly on the ideas of Minkov and Swanepoel of utilising the upper and lower envelopes of the spectrum, which allows us to obtain both the real and imaginary parts of the complex refractive index, and the film thickness. Thickness measurements made by a surface-profiling stylus have been carried out to cross-check the results obtained by the optical method. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. The optical band gap has been determined from absorption coefficient data by Tauc's procedure. Finally, the photo-induced and thermally induced changes in the optical properties of a-As40S40Se20 thin films were also studied, using both transmission and reflection spectra.

  4. A Versatile Strategy for Shish-Kebab-like Multi-heterostructured Chalcogenides and Enhanced Photocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Hu, Jianqiang; Liu, Aili; Jin, Huile; Ma, Dekun; Yin, Dewu; Ling, Pengsheng; Wang, Shun; Lin, Zhiqun; Wang, Jichang

    2015-09-01

    A series of multi-heterostructured metal chalcogenides (CdS-Te, NiS/CdS-Te, and MoS2/CdS-Te) with a surprising shish-kebab-like structure have been synthesized via a one-step microwave-assisted pyrolysis of dithiocarbamate precursors in ethylene glycol. Subsequently, CdS-Te composites were exploited as a self-sacrificial template to craft various CdS-Te@(Pt, Pd) multi-heterostructures. Highly uniform dispersion and intimate interactions between CdS and multicomponent cocatalysts, together with improved separation of photogenerated carriers due to the presence of Te nanotubes (NTs) and trace CdTe, enable CdS-based heterostructured photocatalysts to exhibit greatly enhanced efficiency and stability in the photocatalytic production of H2. Thorough morphological characterizations revealed that the growth of metal sulfide/Te heterostructures originates from the growth of Te tubes, which is likely governed by diffusion-limited depletion of the Te precursor and the dissolution-crystallization process of Te seeds followed by the formation of metal sulfide kebabs.

  5. Size-controlled Intercalation to Conversion Transition in Lithiation of Transition-Metal Chalcogenides – NbSe3

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Langli; Zhao, Benliang; Xiang, Bin; Wang, Chong M.

    2016-01-23

    Transition metal chalcogenides (TMCs) can either be used as intercalation cathodes or as conversion type anodes for lithium ion batteries, for which two distinctively different lithiation reaction mechanisms govern the electrochemical performance of TMCs. However, it remains elusive that what controls the transition of lithiation mechanisms. Herein, we investigated the lithiation process of NbSe3 ribbons using in situ transmission electron microscopy (TEM) and observed a size dependent transition from intercalation to conversion reaction. The large NbSe3 ribbons can accommodate high concentration of Li+ through intercalation by relaxing its internal spacing, while lithiation of small NbSe3 ribbons proceeds readily to full conversion reaction. We find that the size dependent variation of lithiation mechanism is attributed to the Li+ diffusion in NbSe3 and the accommodation of newly formed phases, i.e., insufficient Li+ diffusion and limited space for accommodating the volume expansion induced by forming new phases in large size ribbons both impede the intercalation-to-conversion transition. These results demonstrate the inherent structural instability of NbSe3 as an intercalation cathode and fast lithiation rate as a promising conversion type anode.

  6. Solvothermal and ionothermal syntheses and structures of amine- and/or (poly-)chalcogenide coordinated metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Thiele, Guenther; Santner, Silke; Donsbach, Carsten; Assmann, Maik; Mueller, Marcus; Dehnen, Stefanie [Marburg Univ. (Germany). Fachbereich Chemie und Wissenschaftliches Zentrum fuer Materialwissenschaften

    2014-10-01

    A series of five compounds, namely [Ba(trien){sub 2}]{sub 3}[SbSe{sub 4}]{sub 2}.trien (1) (trien=diethylenetriamine), [(Se{sub 3})Cr(en){sub 2}(Se{sub 2})Cr(en){sub 2}(Se{sub 3})]{sub 2} (2) (en=ethylenediamine), [(pren){sub 3} Eu(Te{sub 3}){sub 2} Eu(pren){sub 3}] (3) (pren=1,3-diaminopropane), [(en){sub 4} Ba(pren)Ba(en){sub 4}](Te{sub 3}){sub 2} (4) and [enH]{sub 4}[Sn{sub 2} Se{sub 6}] (5), which illustrate the transition of classical polychalcogenides to metalates, are presented, where mixed amine/(poly-)chalcogenide interaction with metal centers are in the focus of interest. A conventional aminothermal synthesis is discussed in comparison with ionothermal approaches. The compounds are considered useful precursors to study in situ interconversion of selenido- and telluridometalates under ionothermal conditions.

  7. Size-Controlled Intercalation-to-Conversion Transition in Lithiation of Transition-Metal Chalcogenides-NbSe3.

    Science.gov (United States)

    Luo, Langli; Zhao, Benliang; Xiang, Bin; Wang, Chong-Min

    2016-01-26

    Transition-metal chalcogenides (TMCs) can be used either as intercalation cathodes or as conversion-type anodes for lithium ion batteries, for which two distinctively different lithiation reaction mechanisms govern the electrochemical performance of TMCs. However, the factors that control the transition of lithiation mechanisms remain elusive. In this work, we investigated the lithiation process of NbSe3 ribbons using in situ transmission electron microscopy and observed a size-dependent transition from intercalation to the conversion reaction. Large NbSe3 ribbons can accommodate high concentrations of Li(+) through intercalation by relaxing their internal spacing, while lithiation of small NbSe3 ribbons proceeds readily to full conversion. We found that the size-dependent variation of the lithiation mechanism is associated with both Li(+) diffusion in NbSe3 and the accommodation of newly formed phases. For large NbSe3 ribbons, the intercalation-to-conversion transition is impeded by both long-range Li(+) diffusion and large-scale accommodation of volume expansion induced by the formation of new phases. These results demonstrate the inherent structural instability of NbSe3 as an intercalation cathode and its high lithiation rate as a promising conversion-type anode.

  8. Mineral fibres and cancer.

    Science.gov (United States)

    McDonald, J C

    1984-04-01

    A synthesis is presented of the salient findings to date from laboratory and epidemiological research, on the health effects of asbestos and other natural and man-made mineral fibres. Experimental evidence suggests that all mineral fibres are capable of causing fibrosis and malignancy, with chrysotile at least as pathogenic as other fibres. However, penetration, retention and phagocytosis are affected by size and shape and reactivity and durability by physico-chemical properties. Thus it is not surprising that in man the results of exposure vary considerably with fibre type and industrial process. A considerable body of evidence suggests that chrysotile has seldom, if ever, caused peritoneal mesothelioma and that the great majority of pleural mesotheliomas are also attributable to crocidolite or amosite. Without more reliable information on intensity and duration of exposure by fibre type, the epidemiological evidence on this point cannot be wholly conclusive. There are stronger grounds from a limited number of cohort studies for believing that in relation to estimated exposure, the risk of lung cancer has been much higher in textile plants than in fibre production or in the manufacture of friction products, with asbestos-cement plants somewhere in between. The data on man-made fibre production remains equivocal. It is concluded that attempts to regulate asbestos without regard for fibre type, although perhaps adequate for lung cancer and fibrosis, may do little to reduce the risk of mesothelioma. The search for safe fibre substitutes for asbestos will remain difficult until the parameters of pathogenicity are better understood.

  9. Spectroscopic characterization of manganese minerals

    Science.gov (United States)

    Lakshmi Reddy, S.; Padma Suvarna, K.; Udayabhaska Reddy, G.; Endo, Tamio; Frost, R. L.

    2014-01-01

    Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals.

  10. Radioactivity of phosphate mineral products

    OpenAIRE

    Mitrović Branislava; Vitorović Gordana; Stojanović Mirjana; Vitorović Duško

    2011-01-01

    The phosphate industry is one of the biggest polluters of the environment with uranium. Different products are derived after processing phosphoric ore, such as mineral and phosphate fertilizers and phosphate mineral supplements (dicalcium-and monocalcium phosphate) for animal feeding. Phosphate mineral additives used in animal food may contain a high activity of uranium. Research in this study should provide an answer to the extent in which phosphate minera...

  11. Investigation of high tension chalcogenide glass micro-structure optical fibers%高强度硫系玻璃微结构光纤研究

    Institute of Scientific and Technical Information of China (English)

    何钰钜; 王训四; 聂秋华; 张培全; 徐会娟; 徐铁峰; 戴世勋; 张培晴

    2013-01-01

    Chalcogenide glass micro-structure optical fibers (CGMOFs) have wide potential applications in the field of infrared laser energy transmission and infrared optical fiber sensing for their unique optical properties. The problem is that there is no good method to prepare chalcogenide glass micro-structure optical fibers up to now. In this paper,we attempt to fabricate chalcogenide glass micro-structure optical fibers by using the press forming method. A glass extruder is designed to extrude Ge20 Sb15 Se65 chalcogenide glass into a multi-hole fiber preforms. Then,the extruder preform is drawn into fiber using an improved fiber drawing machine. The infrared transmitting property is measured by using infrared thermal imager and infrared spectrometer. The optical loss of extruded glass is calculated based on the infrared transmission spectra of glass disks with different thicknesses. We also measure fiber cross-section and its diameter by scanning electron microscope (SEM). The results show that the infrared transmission spectra of the extruded glass have not decreased obviously. The optical losses of the glasses before and after extruding at 10 μm are 0. 25 dB/cm and 0. 27 dB/cm. respectively. The strength of chalcogenide glass fiber protected by a thin layer of plastic polymer is 1.45 times of that of a standard silica fiber,promoting the development of chalcogenide glass micro-structure optical fibers.%针对硫系玻璃微结构光纤缺少有效制备方法的问题,本文选用可塑性较好的Ge20Sb15Se65硫系玻璃,利用自制的硫系玻璃挤压机制备了多孔硫系玻璃微结构光纤(CGMOF).利用红外热像仪以及傅里叶红外光谱仪测试了挤压前后玻璃的红外透过性能、根据不同厚度玻璃片的透过谱,计算了挤压后玻璃的光学损耗特性.利用扫描电子显微镜观察拉制光纤的横截面,测试了光纤的直径.分析结果表明,挤压后的硫系玻璃的红外透过率和损耗较挤压前没有显著

  12. Mineralization by nanobacteria

    Science.gov (United States)

    Kajander, E. Olavi; Bjorklund, Michael; Ciftcioglu, Neva

    1998-07-01

    Nanobacteria are the smallest cell-walled bacteria, only recently discovered in human and cow blood and in commercial cell culture serum. In this study, we identified with energy-dispersive x-ray microanalysis and chemical analysis that all growth phases of nanobacteria produce biogenic apatite on their cell envelope. Fourier transform IR spectroscopy revealed the mineral as carbonate apatite. Previous models for stone formation have lead to a hypothesis that an elevated pH due to urease and/or alkaline phosphatase activity are important lithogenic factors. Our results indicate that carbonate apatite can be formed without these factors at pH 7.4 at physiological phosphate and calcium concentrations. Due to their specific macromolecules, nanobacteria can produce apatite very efficiency in media mimicking tissue fluids and glomerular filtrate and rapidly mineralizing most of available calcium and phosphate. This can be also monitored by (superscript 85)Sr incorporation and provides a unique model for in vitro studies on calcification. Recently, bacteria have been implicated in the formation of carbonate (hydroxy)fluorapatite in marine sediments. Apatite grains are found so commonly in sedimentary rocks that apatite is omitted in naming the stone. To prove that apatite and other minerals are formed by bacteria would implicate that the bacteria could be observed and their actions followed in stones. We have started to approach this in two ways. Firstly, by the use of sensitive methods for detecting specific bacterial components, like antigens, muramic acid and nucleic acids, that allow for detecting the presence of bacteria and, secondly, by follow-up of volatile bacterial metabolites observed by continuous monitoring with ion mobility spectrometry, IMCELL, working like an artificial, educatable smelling nose. The latter method might allow for remote real time detection of bacterial metabolism, a signature of life, in rocks via fractures of drillholes with or without

  13. Memory type switching behavior of ternary Ge20Te80-x Sn x (0  ⩽  x  ⩽  4) chalcogenide compounds

    Science.gov (United States)

    Jeevan Fernandes, Brian; Sridharan, Kishore; Munga, Pumlian; Ramesh, K.; Udayashankar, N. K.

    2016-07-01

    Chalcogenide compounds have gained huge research interest recently owing to their capability to transform from an amorphous to a crystalline phase with varying electrical properties. Such materials can be applied in building a new class of memories, such as phase-change memory and programmable metallization cells. Here we report the memory type electrical switching behavior of a ternary chalcogenide compound synthesized by doping Tin (Sn) in a germanium-telluride (Ge20Te80) host matrix, which yielded a composition of Ge20Te80-x Sn x (0  ⩽  x  ⩽  4). Results indicate a remarkable decrease in the threshold switching voltage (V T) from 140 to 61 V when the Sn concentration was increased stepwise, which is attributed to the domination of the metallicity factor leading to reduced amorphous network connectivity and rigidity. Variation in the threshold switching voltage (V T) was noticed even when the sample thickness and temperature were altered, confirming that the memory switching process is of thermal origin. Investigations using x-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed the formation of a crystalline channel that acts as the conduction path between the two electrodes in the switched region. Structural and morphological studies indicated that Sn metal remained as a micro inclusion in the matrix and hardly contributed to the rigid amorphous network formation in Ge20Te80-x Sn x . Memory type electrical switching observed in these ternary chalcogenide compounds synthesized herein can be explored further for the fabrication of phase-change memory devices.

  14. Magnesium-induced copper-catalyzed synthesis of unsymmetrical diaryl chalcogenide compounds from aryl iodide via cleavage of the Se-Se or S-S bond.

    Science.gov (United States)

    Taniguchi, Nobukazu; Onami, Tetsuo

    2004-02-06

    The methodology for a copper-catalyzed preparation of diaryl chalcogenide compounds from aryl iodides and diphenyl dichalcogenide molecules is reported. Unsymmetrical diaryl sulfide or diaryl selenide can be synthesized from aryl iodide and PhYYPh (Y = S, Se) with a copper catalyst (CuI or Cu(2)O) and magnesium metal in one pot. This reaction can be carried out under neutral conditions according to an addition of magnesium metal as the reductive reagent. Furthermore, it is efficiently available for two monophenylchalcogenide groups generated from diphenyl dichalcogenide.

  15. Mid-infrared supercontinuum generation in chalcogenide step-index fibers pumped at 2.9 and 4.5µm

    OpenAIRE

    Kubat, Irnis; Agger, Christian; Møller, Uffe Visbech; SEDDON, Angela; Tang, Zhuoqi; Sujecki, Slawomir; Benson, Trevor M.; Furniss, David; Lamrini, Samir; Scholle, Karsten; Fuhrberg, Peter; Napier, Bruce; Farries, Mark; Ward, Jon; Moselund, Peter M.

    2014-01-01

    The Mid-InfraRed (MIR) spectral range (2-12µm) contains the spectral fingerprint of many organic molecules, which can be probed nondestructively for e.g. detection of skin cancer. For this SuperContinuum (SC) laser sources are good candidates since they can have broadband bandwidths together with high spectral densities. Here we consider a MIR SC laser sources based on chalcogenide step-index fibers with exceptionally high numerical aperture of ~1 pumped either with Er:ZBLAN and Pr:CHALC fibe...

  16. Pressure induced structural phase transition of PrX, PrY (X = S, Se, Te) chalcogenides and (Y = N, P, As) pnictides

    Science.gov (United States)

    Varshney, Dinesh; Shriya, Swarna; Dube, A.; Varshney, Meenu

    2012-06-01

    Pressure induced structural aspects of NaCl-type (B1) to CsCl-type (B2) structure in Praseodymium pnictides and chalcogenides are presented. An effective interionic interaction potential with long range Coulomb, van der Waals interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge is developed. Deduced results on volume discontinuity in pressure volume phase diagram identify the structural phase transition from B1 to B2 structure consistent with the known results.

  17. Minerals From the Marine Environment

    Science.gov (United States)

    Cruickshank, Michael J.

    The current interest in minerals centering on, among other things, potential shortages, long-term needs, and deep seabed nodules, accentuates the usefulness and timeliness of this little book authored by a former chairman of the British National Environmental Research Council.In less than 100 pages, the author puts into perspective the potential for producing minerals from offshore areas of the world. After introducing the reader to the ocean environment and the extraordinary variety of the nature of the seabed, the author describes in some detail the variety of minerals found there. This is done in seven separate chapters entitled ‘Bulk and Non-Metallic Minerals From the Seas’ ‘Metals From the Shallow Seas’ ‘Metals From the Deep Oceans’ ‘Minerals From Solution’ ‘Oil and Gas from the Shallow Seas’ ‘Oil and Gas From Deep Waters’ and ‘Coal Beneath the Sea.’ The remaining chapters give a brief regional review of marine minerals distribution for eight areas of significant socioeconomic structure, and a short recapitulation of special problems of mineral recovery in the marine environment including such matters as the effect of water motion on mineral processing and of international law on investments. Glossaries of geological periods and technical terms, a short list of references, and an index complete the work.

  18. Mineral Atlas of the World

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    In 1997 the mineral resources of Europe and neighbouring countries were presented as a printed map and a book of exhaustive information and references. This was the first published map inventory of mineral deposits from all parts of the formerly politically divided Europe (East and West), measured and evaluated according to identical geological and mining standards.

  19. A Mineral Processing Field Course

    Science.gov (United States)

    Carmody, Maurice

    2014-01-01

    This article describes a field course in Cornwall looking at mineral processing with the focus on the chemistry involved. The course was split into two parts. The first looked at tin mining based around Penzance. This involved visiting mines, hunting for mineral samples, carrying out a stream survey and visiting the Camborne School of Mines…

  20. 75 FR 80947 - Conflict Minerals

    Science.gov (United States)

    2010-12-23

    ... violence in the eastern Democratic Republic of the Congo, particularly sexual- and gender-based violence... conflict free,'' the facilities used to process the conflict minerals, the country of origin of the conflict minerals, and ``the efforts to determine the mine or location of origin with the greatest...

  1. Plant macro- and micronutrient minerals

    Science.gov (United States)

    All plants must obtain a number of inorganic mineral elements from their environment to ensure successful growth and development of both vegetative and reproductive tissues. A total of fourteen mineral nutrients are considered to be essential. Several other elements have been shown to have beneficia...

  2. Investigation of Kinetics of crystallization Processes of S15-Se85, S15-Se81-Cu4 Chalcogenide glasses

    Science.gov (United States)

    Samudrala, Kavitha; Babu Devarasetty, Suresh

    2016-09-01

    In the present work, S15-Se85, S15-Se81-Cu4 chalcogenide glasses are prepared by using conventional melt quenching technique. The as-prepared samples are studied by experimental techniques like X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC). XRD studies have confirmed that the as-prepared samples are amorphous in nature. It is clear from DSC studies that the as-prepared samples are glassy in nature. Kinetic analysis of the crystallization process of as-prepared glasses is carried using DSC curves. Activation energy for glass transition and Activation energy for crystallization are determined using Kissinger method. Activation energy for glass transition of S15-Se85 and S15-Se81-Cu4 glasses is found to be 84.5076 and 275.801 KJ/Mole respectively. Activation energy for crystallization of S15-Se85 glass is found to be 106.2622 KJ/Mole for 1st peak while Activation energy for crystallization of S15-Se81-Cu4 glasses is found to be 97.93 KJ/Mole for 1st peak and 84.20 KJ/Mole for 2nd peak. Kauzmann temperature (Tk) is determined from the heating rate dependent glass transition and crystallization temperatures. Tk value for S15-Se85 glass sample is 236.680K (1st peak) and for S15-Se81-Cu4 is 283.530K (1st peak) and 286.330K (2n peak). Avrami Index (n) is also determined for as-prepared glasses. Avrami Index (n) value for S15-Se85 glass sample is 1.8 (1st peak) and for S15-Se81-Cu4 is 2.9 (1st peak) and 1.4 (2nd peak). The crystalline phases by thermal treatment of as-prepared glasses are identified using XRD patterns.

  3. Thermoelectric properties of chalcogenide based Cu2+xZnSn1−xSe4

    Directory of Open Access Journals (Sweden)

    Ch. Raju

    2013-03-01

    Full Text Available Quaternary chalcogenide compounds Cu2+xZnSn1−xSe4 (0 ≤ x ≤ 0.15 were prepared by solid state synthesis. Rietveld powder X-ray diffraction (XRD refinements combined with Electron Probe Micro Analyses (EPMA, WDS-Wavelength Dispersive Spectroscopy and Raman spectra of all samples confirmed the stannite structure (Cu2FeSnS4-type as the main phase. In addition to the main phase, small amounts of secondary phases like ZnSe, CuSe and SnSe were observed. Transport properties of all samples were measured as a function of temperature in the range from 300 K to 720 K. The electrical resistivity of all samples decreases with an increase in Cu content except for Cu2.1ZnSn0.9Se4, most likely due to a higher content of the ZnSe. All samples showed positive Seebeck coefficients indicating that holes are the majority charge carriers. The thermal conductivity of doped samples was high compared to Cu2ZnSnSe4 and this may be due to the larger electronic contribution and the presence of the ZnSe phase in the doped samples. The maximum zT = 0.3 at 720 K occurs for Cu2.05ZnSn0.95Se4 for which a high-pressure torsion treatment resulted in an enhancement of zT by 30% at 625 K.

  4. Optical properties change in laser-induced Te/As{sub 2}Se{sub 3} chalcogenide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Mukta; Naik, Ramakanta [Utkal University, Department of Physics, Bhubaneswar (India)

    2016-10-15

    In the present work, we report the change in optical parameters due to the deposition and photo-induced diffusion of Te layer into the chalcogenide As{sub 2}Se{sub 3} film. The photo-diffusion creates a solid solution of As-Se-Te which has potential application in optical devices. The Te/As{sub 2}Se{sub 3} bilayer films prepared by thermal evaporation technique were studied by various experimental techniques. The photo-diffusion of Te into As{sub 2}Se{sub 3} matrix was done by 532-nm laser irradiation. The structure of the As{sub 2}Se{sub 3}, as-prepared and irradiated Te/As{sub 2}Se{sub 3} films was studied by X-ray diffraction which were amorphous in nature. The presence of all the elements was checked by energy-dispersive X-ray analysis, and the optical transmission spectra were recorded by Fourier transform infrared spectrometer. The optical band gap is reduced by the deposition and diffusion of Te into As{sub 2}Se{sub 3} film which is due to the increase in density of defect states in the gap region. The transmission is decreased, whereas the absorption efficiency is increased with the increase in disorderness. The X-ray photoelectron spectroscopy carried out on these films gives information about the bonding change due to the photo-diffusion process. Therefore, this is an important result which will open up new directions for the application of this material in semiconducting devices. (orig.)

  5. Methods of thermoelectric enhancement in silicon-germanium alloy type I clathrates and in nanostructured lead chalcogenides

    Science.gov (United States)

    Martin, Joshua

    The rapid increase in thermoelectric (TE) materials R&D is a consequence of the growing need to increase energy efficiency and independence through waste heat recovery. TE materials enable the direct solid-state conversion of heat into electricity, with little maintenance, noise, or cost. In addition, these compact devices can be incorporated into existing technologies to increase the overall operating efficiency. High efficiency TE materials would enable the practical solid-state conversion of thermal to electrical energy. Optimizing the interdependent physical parameters to achieve acceptable efficiencies requires materials exhibiting a unique combination of properties. This research reports two methods of thermoelectric enhancement: lattice strain effects in silicon-germanium alloy type I clathrates and the nanostructured enhancement of lead chalcogenides. The synthesis and chemical, structural, and transport properties characterization of Ba8Ga16SixGe30-x type I clathrates with similar Ga-to-group IV element ratios but with increasing Si substitution (4 materials were then further optimized by adjusting the Ga-to-group IV element ratios. Recent progress in a number of higher efficiency TE materials can be attributed to nanoscale enhancement. Many of these materials demonstrate increased Seebeck coefficient and decreased thermal conductivity due to the phenomenological properties of nanometer length scales. To satisfy the demands of bulk industrial applications requires additional synthesis techniques to incorporate nanostructure directly within a bulk matrix. This research investigates, for the first time, dense dimensional nanocomposites prepared by densifying nanocrystals synthesized employing a solution-phase reaction. Furthermore, the carrier concentration of the PbTe nanocomposites can be adjusted by directly doping the nanocrystals, necessary for power factor optimization. These materials were fully characterized using a low temperature TE transport

  6. Structure and Properties of Modified and Charge-Compensated Chalcogenide Glasses in the Na/Ba-Ga-Ge Selenide System

    Science.gov (United States)

    Mao, Alvin W.

    Chalcogenide glasses exhibit unique optical properties such as infrared transparency owing to the low-phonon energies, optical non-linearity, and photo-induced effects that have important consequences for a wide range of technological applications. However, to fully utilize these properties, it is necessary to better understand the atomic-scale structure and structure-property relationships in this important class of materials. Of particular interest in this regard are glasses in the stoichiometric system Na2Se/BaSe--Ga 2Se3--GeSe2 as they are isoelectronic with the well-studied, oxide glasses of the type M2O(M'O)--Al 2O3--SiO2 (M = alkali, M' = alkaline earth). This dissertation investigates the structure of stoichiometric Na 2Se/BaSe--Ga2Se3--GeSe2 and off-stoichiometric BaSe--Ga2Se3--GeSe 2+/-Se glasses using a combination of Fourier-transform Raman and solid state nuclear magnetic resonance (NMR) spectroscopies. The spectroscopic data is then compared to composition-dependent trends in physical properties such as density, optical band gap, glass transition temperature, and melt fragility to develop predictive structural models of the short- and intermediate-range order in the glass network. These models significantly improve our current understanding of the effects of modifier addition on the structure and properties of chalcogenide glasses, and thus enable a more efficient engineering of these highly functional materials for applications as solid electrolytes in batteries or as optical components in infrared photonics. In general, the underlying stoichiometric Ga2Se3--GeSe 2 network consists primarily of corner-sharing (Ga/Ge)Se4 tetrahedra, where the coordination numbers of Ga, Ge, and Se are 4, 4, and 2, respectively. Some edge-sharing exists, but this configuration is relatively unstable and its concentration tends to decrease with any deviation from the GeSe2 composition. Due to the tetrahedral coordination of Ga, the initial addition of Se-deficient Ga2Se

  7. 30 CFR 57.5070 - Miner training.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Miner training. 57.5070 Section 57.5070 Mineral... Agents, and Diesel Particulate Matter Diesel Particulate Matter-Underground Only § 57.5070 Miner training. (a) Mine operators must provide annual training to all miners at a mine covered by this part who...

  8. Mineral mining installation

    Energy Technology Data Exchange (ETDEWEB)

    Weirich, W.

    1984-01-24

    A longwall mineral mining installation has a conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. Each roof support unit has a roof shield having an advanceable shield extension. Each unit has a first hydraulic ram for extending its shield extension, and a second hydraulic ram for advancing the conveyor. The extension of each first ram is controlled in dependence upon the retraction of one of the second rams (either the second ram of the same unit or that of an adjacent unit). This control is effected by controlling the supply of pressurized hydraulic fluid to the first rams. In one embodiment this is carried out by a control valve which has a springloaded plunger which engages with a series of equispaced cams on the movable cylinder of the associated second ram. In another embodiment, the piston rods of the rams are provided with series of equispaced magnets. The cylinders of the rams are provided with sensors, which sense the magnets and generate control signals. A control box is provided to direct the control signals to control valves associated with the rams, so that the first rams are extended by the same distance as that through which the second rams are retracted.

  9. Mineral mining installation

    Energy Technology Data Exchange (ETDEWEB)

    Becker, K.; Rosenberg, H.; Weirich, W.

    1981-12-29

    A longwall mineral mining installation has a conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. Each roof support unit has a roof shield having an advanceable shield extension. Each unit has a first hydraulic ram for extending its shield extension, and a second hydraulic ram for advancing the conveyor. The extension of each first ram is controlled in dependence upon the retraction of one of the second rams (Either the second ram of the same unit or that of an adjacent unit). This control is effected by controlling the supply of pressurized hydraulic fluid to the first rams. In one embodiment this is carried out by a control valve which has a spring-loaded plunger which engages with a series of equispaced cams on the movable cylinder of the associated second ram. In another embodiment, the piston rods of the rams are provided with series of equispaced magnets. The cylinders of the rams are provided with sensors, which sense the magnets and generate control signals. A control box is provided to direct the control signals to control valves associated with the rams, so that the first rams are extended by the same distance as that through which the second rams are retracted.

  10. Economic drivers of mineral supply

    Science.gov (United States)

    Wagner, Lorie A.; Sullivan, Daniel E.; Sznopek, John L.

    2003-01-01

    The debate over the adequacy of future supplies of mineral resources continues in light of the growing use of mineral-based materials in the United States. According to the U.S. Geological Survey, the quantity of new materials utilized each year has dramatically increased from 161 million tons2 in 1900 to 3.2 billion tons in 2000. Of all the materials used during the 20th century in the United States, more than half were used in the last 25 years. With the Earth?s endowment of natural resources remaining constant, and increased demand for resources, economic theory states that as depletion approaches, prices rise. This study shows that many economic drivers (conditions that create an economic incentive for producers to act in a particular way) such as the impact of globalization, technological improvements, productivity increases, and efficient materials usage are at work simultaneously to impact minerals markets and supply. As a result of these economic drivers, the historical price trend of mineral prices3 in constant dollars has declined as demand has risen. When price is measured by the cost in human effort, the price trend also has been almost steadily downward. Although the United States economy continues its increasing mineral consumption trend, the supply of minerals has been able to keep pace. This study shows that in general supply has grown faster than demand, causing a declining trend in mineral prices.

  11. Structural features of spin-coated thin films of binary As{sub x}S{sub 100−x} chalcogenide glass system

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J. [Austin Peay State University, Clarksville, TN 37075 (United States); Slang, S. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Golovchak, R. [Austin Peay State University, Clarksville, TN 37075 (United States); Jain, H. [International Materials Institute for New Functionality in Glass, Lehigh University, Bethlehem, PA 18015 (United States); Vlcek, M. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Kovalskiy, A., E-mail: kovalskyya@apsu.edu [Austin Peay State University, Clarksville, TN 37075 (United States)

    2015-08-31

    Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As{sub x}S{sub 100−x} (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As{sub 2}O{sub 3} was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films.

  12. Mid-infrared supercontinuum generation to 12.5μm in large NA chalcogenide step-index fibres pumped at 4.5μm

    DEFF Research Database (Denmark)

    Kubat, Irnis; Agger, Christian; Møller, Uffe Visbech;

    2014-01-01

    We present numerical modeling of mid-infrared (MIR) supercontinuum generation (SCG) in dispersion-optimized chalcogenide (CHALC) step-index fibres (SIFs) with exceptionally high numerical aperture (NA) around one, pumped with mode-locked praseodymium-doped (Pr3+) chalcogenide fibre lasers. The 4.......5um laser is assumed to have a repetition rate of 4MHz with 50ps long pulses having a peak power of 4.7kW. A thorough fibre design optimisation was conducted using measured material dispersion (As-Se/Ge-As-Se) and measured fibre loss obtained in fabricated fibre of the same materials. The loss...... was below 2.5dB/m in the 3.3-9.4μ m region. Fibres with 8 and 10μm core diameters generated an SC out to 12.5 and 10.7μm in less than 2m of fibre when pumped with 0.75 and 1kW, respectively. Larger core fibres with 20μm core diameters for potential higher power handling generated an SC out to 10.6μm...

  13. Engel-Vosko GGA Approach Within DFT Investigations of the Optoelectronic Structure of the Metal Chalcogenide Semiconductor CsAgGa2Se4

    Science.gov (United States)

    Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya

    2016-01-01

    Metal chalcogenide semiconductors have a significant role in the development of materials for energy and nanotechnology applications. First principle calculations were applied on CsAgGa2Se4 to investigate its optoelectronic structure and bonding characteristics, using the full-potential linear augmented plane wave method within the framework of generalized gradient approximations (GGA) and Engel-Vosko GGA functionals (EV-GGA). The band structure from EV-GGA shows that the valence band maximum and conduction band minimum are situated at Γ with a band gap value of 2.15 eV. A mixture of orbitals from Ag 4 p 6/4 d 10, Se 3 d 10, Ga 4 p 1, Se 4 p 4 , and Ga 4 s 2 states have a primary role to lead to a semiconducting character of the present chalcogenide. The charge density iso-surface shows a strong covalent bonding between Ag-Se and Ga-Se atoms. The imaginary part of dielectric constant reveals that the threshold (first optical critical point) energy of dielectric function occurs 2.15 eV. It is obvious that with a direct large band gap and large absorption coefficient, CsAgGa2Se4 might be considered a potential material for photovoltaic applications.

  14. A New Design of As2Se3‎ Chalcogenide Glass Photonic Crystal Fiber with Ultra-Flattened Dispersion in Mid-Infrared Wavelength Range

    Directory of Open Access Journals (Sweden)

    Mahmood Seifouri

    2014-12-01

    Full Text Available In this paper, we report a new design of As2Se3‎ chalcogenide glass photonic crystal fiber (PCF with ultra-flattened dispersion at mid-infrared wavelength range. We have used the plane wave expansion method (PWE for designing the structure of As2Se3‎ glass PCF at different wavelength windows. In the proposed structure with hole to hole spacing and , the negative dispersion is -1025 ps/nm/km at the wavelength of 1.55µm, and also an ultra-flattened dispersion is achieved at the wavelength range of 3.5-18μm. Hence such PCFs have a high potential to be used as dispersion compensating fibers at 1.55µm wavelength in optical communication systems. The ultra-flattened dispersion at the wavelength range of 3.5-18μm can be employed to achieve high power super-continuum generation. The nonlinear coefficient of the proposed PCF is 1.5 W-1m-1 at the wavelength of 1.55µm. Chalcogenide glasses are known to have both high transparency and nonlinearity in a wide range of infrared wavelengths compared to silica glasses.

  15. Glycine Polymerization on Oxide Minerals

    Science.gov (United States)

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

    2016-07-01

    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  16. Multiple-State Storage Capability of Stacked Chalcogenide Films (Si16Sb33Te51/Si4Sb45Te51/Si11Sb39Te50) for Phase Change Memory

    Institute of Scientific and Technical Information of China (English)

    LAI Yun-Feng; FENG Jie; QIAO Bao-Wei; HUANG Xiao-Gang; CAI Yan-Fei; LIN Yin-Yin; TANG Ting-Ao; CAI Bing-Chu; CHEN Bomy

    2006-01-01

    @@ The multiple-state storage capability of phase change memory (PCM) is confirmed by using stacked chalcogenide films as the storage medium. The current-voltage characteristics and the resistance-current characteristics of the PCM clearly indicate that four states can be stored in this stacked film structure.

  17. Mineral mining machines

    Energy Technology Data Exchange (ETDEWEB)

    Mc Gaw, B.H.

    1984-01-01

    A machine for mining minerals is patented. It is a cutter loader with a drum actuating element of the worm type equipped with a multitude of cutting teeth reinforced with tungsten carbide. A feature of the patented machine is that all of the cutting teeth and holders on the drum have the identical design. This is achieved through selecting a slant angle for the cutting teeth which is the mean between the slant angle of the conventional radial teeth and the slant angle of the advance teeth. This, in turn, is provided thanks to the corresponding slant of the holders relative to the drum and (or) the slant of the cutting part of the teeth relative to their stems. Thus, the advance teeth projecting beyond the surface of the drum on the face side and providing upper and lateral clearances have the same angle of attack as the radial teeth, that is, from 20 to 35 degrees. A series of modifications of the cutting teeth is patented. One of the designs allows the cutting tooth to occupy a varying position relative to the drum, from the conventional vertical to an inverted, axially projecting position. In the last case the tooth in the extraction process provides the upper and lateral clearances for the drum on the face side. Among the different modifications of the cutting teeth, a design is proposed which provides for the presence of a stem which is shaped like a truncated cone. This particular stem is designed for use jointly with a wedge which unfastens the teeth and is placed in a holder. The latter is completed in a transverse slot thanks to which the rear end of the stem is compressed, which simplifies replacement of a tooth. Channels are provided in the patented machine for feeding water to the worm spiral, the holders and the cutting teeth themselves in order to deal with dust.

  18. Mineral Commodity Profiles -- Rubidium

    Science.gov (United States)

    Butterman, W.C.; Reese, R.G.

    2003-01-01

    Overview -- Rubidium is a soft, ductile, silvery-white metal that melts at 39.3 ?C. One of the alkali metals, it is positioned in group 1 (or IA) of the periodic table between potassium and cesium. Naturally occurring rubidium is slightly radioactive. Rubidium is an extremely reactive metal--it ignites spontaneously in the presence of air and decomposes water explosively, igniting the liberated hydrogen. Because of its reactivity, the metal and several of its compounds are hazardous materials, and must be stored and transported in isolation from possible reactants. Although rubidium is more abundant in the earth?s crust than copper, lead, or zinc, it forms no minerals of its own, and is, or has been, produced in small quantities as a byproduct of the processing of cesium and lithium ores taken from a few small deposits in Canada, Namibia, and Zambia. In the United States, the metal and its compounds are produced from imported raw materials by at least one company, the Cabot Corporation (Cabot, 2003). Rubidium is used interchangeably or together with cesium in many uses. Its principal application is in specialty glasses used in fiber optic telecommunication systems. Rubidium?s photoemissive properties have led to its use in night-vision devices, photoelectric cells, and photomultiplier tubes. It has several uses in medical science, such as in positron emission tomographic (PET) imaging, the treatment of epilepsy, and the ultracentrifugal separation of nucleic acids and viruses. A dozen or more other uses are known, which include use as a cocatalyst for several organic reactions and in frequency reference oscillators for telecommunications network synchronization. The market for rubidium is extremely small, amounting to 1 to 2 metric tons per year (t/yr) in the United States. World resources are vast compared with demand.

  19. Book review: Mineral resource estimation

    Science.gov (United States)

    Mihalasky, Mark J.

    2016-01-01

    Mineral Resource Estimation is about estimating mineral resources at the scale of an ore deposit and is not to be mistaken with mineral resource assessment, which is undertaken at a significantly broader scale, even if similar data and geospatial/geostatistical methods are used. The book describes geological, statistical, and geostatistical tools and methodologies used in resource estimation and modeling, and presents case studies for illustration. The target audience is the expert, which includes professional mining geologists and engineers, as well as graduate-level and advanced undergraduate students.

  20. BET measurements: Outgassing of minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    Outgassing minerals at elevated temperatures prior to BET measurements can lead to phase changes, especially in the case of amorphous and poorly crystalline materials. In order to evaluate the applicability of the BET method when low outgassing temperatures are required, selected aquifer minerals...... were outgassed at different temperatures and for different times. The studied minerals are 2-line ferrihydrite, goethite, lepidocrocite, quartz, calcite, ®-alumina, and kaolinite. The results demonstrate that measured specific surface areas of iron oxides are strongly dependent on outgassing conditions...... because the surface area increased by 170% with increasing temperature. In the poorly crystalline minerals, phase changes caused by heating were observed at temperatures lower than 100±C. Therefore low outgassing temperatures are preferable for minimizing phase changes. As demonstrated in this study...

  1. Nondigestible carbohydrates and mineral bioavailability.

    Science.gov (United States)

    Greger, J L

    1999-07-01

    Generally, fiber and compounds associated with fiber in cereal products (e.g., phytates) have been found to reduce the apparent absorption of minerals (such as calcium, magnesium, zinc and manganese) in humans, livestock and animal models. The effects of "soluble" forms of fiber (specifically pectins, gums, resistant starches, lactulose, oligofructose and inulin) on mineral absorption are more difficult to characterize. The addition of these soluble forms of fiber has been found in various studies to add viscosity to the gut contents, promote fermentation and the production of volatile fatty acids in the cecum, have a trophic effect on the ceca of animals and increase serum enteroglucagon concentrations. Thus it is not surprising that the addition of soluble forms of fiber to diets often has been found to improve absorption of minerals. This may reflect absorption of electrolytes from the large intestine. Future work should address the mechanisms by which ingestion of nondigestible carbohydrates improves mineral absorption in humans.

  2. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111673 Cao Ban(Zhejiang Institute of Geological & Mineral Resources,Hangzhou 310007,China);Ma Jun Determination of 16 Polycyclic Aromatic Hydrocarbons in Groundwater by High Performance Liquid Chromatography with Fluorescence-Ultraviolet Detector(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(5),2010,p.539-542,2 illus.,4 tables,15 refs.)Key words:liquid chromatography,polycyclic aromatic hydrocarbons,fluorescence analysis

  3. Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide diamond-like semiconductors

    Science.gov (United States)

    Berarma, K.; Charifi, Z.; Soyalp, F.; Baaziz, H.; Uğur, G.; Uğur, Ş.

    2016-12-01

    Using first-principles calculations based on density functional theory, the structural, electronic and thermodynamic properties of Li2CdGeS4 and Li2CdSnS4 compounds are investigated. We confirmed that both Li2CdGeS4 and Li2CdSnS4 are diamond-like semiconductors of the wurtz-stannite structure type based on that of diamond in terms of tetrahedra volume. All the tetrahedra are almost regular with major distortion from the ideal occurring in the LiS4 tetrahedron, with values for S-Li-S ranging from 105.69° to 112.84° in the Li2CdGeS4 compound. Furthermore, the Cd-S bond possesses a stronger covalent bonding strength than the Li/Ge-S bonds. In addition, the inter-distances in Li2CdSnS4 show a larger spread than the distances in the Li2CdGeS4 compound. The electronic structures have been calculated to understand the bonding mechanism in quaternary Li-containing chalcogenide diamond-like semiconductors. Our results show that Li2CdGeS4 and Li2CdSnS4 are semiconductors with a direct band gap of 2.79 and 2.42 eV and exhibit mixed ionic-covalent bonding. It is also noted that replacing Ge by Sn leads to a decrease in the band gap; this behavior is explained in terms of bond lengths and electronegativity differences between atoms. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy are calculated and show an optical anisotropy for Li2CdGeS4 and Li2CdSnS4. The static dielectric constant {\\varepsilon }1(0) and static refractive index n(0) decrease when Ge is replaced by Sn. The influence of pressures and temperatures on the thermodynamic properties like the specific heat at constant volume {C}v, and at constant pressure {C}p, the Debye temperature {{{\\Theta }}}{{D}}, the entropy S and the Grüneisen parameter γ have been predicted at enlarged pressure and temperature ranges. The principal aspect from the obtained results is the close similarity of both compounds.

  4. Study on mineral processing technology for abrasive minerals

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Woong; Yang, Jung Il; Hwang, Seon Kook; Choi, Yeon Ho; Cho, Ken Joon; Shin, Hee Young [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-01

    Buyeo Materials in Buyeogun, Choongnam province is a company producing feldspar concentrate, but does not yet utilize the garnet as abrasive material and other useful heavy minerals wasted out from the process of feldspar ore. The purpose of this study is to develop technology and process for the recovery of garnet concentrate. As results, the garnet is defined as ferro manganese garnet. The optimum process for recovery of garnet concentrate is to primarily concentrate heavy minerals from tailings of feldspar processing. And secondly the heavy minerals concentrated is dried and separated garnet concentrate from other heavy minerals. At this time, the garnet concentrate is yield by 0.176%wt from 0.31%wt of heavy minerals in head ore. The garnet concentrate contains 33.35% SiO{sub 2}, 12.20% Al{sub 2}O{sub 3}, 28.47% Fe{sub 2}O{sub 3}, 11.96% MnO. As for utilization of abrasive materials, a fundamental data was established on technology of grinding and classification. (author). 13 refs., 47 figs., 24 tabs.

  5. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  6. [Mineral water as a cure].

    Science.gov (United States)

    Nocco, Priska Binz

    2008-01-01

    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  7. Two new ternary lanthanide antimony chalcogenides: Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 4}Sb{sub 2}Se{sub 11.68} containing chalcogenide Q{sup 2-} and dichalcogenide (Q{sub 2}){sup 2-} anions

    Energy Technology Data Exchange (ETDEWEB)

    Babo, Jean-Marie [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Albrecht-Schmitt, Thomas E., E-mail: talbrec1@nd.edu [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2012-03-15

    Dark red and dark brown crystals of Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 8}Sb{sub 4}Se{sub 11.68}, respectively, were obtained from the reaction of the elements in Sb{sub 2}Q{sub 3} (Q=S, Se) fluxes. Both non-stoichiometric compounds are orthorhombic and crystallize in the same space group Pnnm, with two formula units per unit cell (a=12.446(2), b=5.341(1), c=12.058(2) for sulfide and a=13.126(2), b=5.623(1), c=12.499(2) for the selenide). Their crystal structures are dominated by lanthanide-chalcogenide polyhedra (CN=7 and 8), which share corners, edges, triangular- and square-faces to form a three-dimensional framework embedding antinomy cations. The latter are coordinated by three sulfide anions with 5(1+2+2) secondary contacts forming basically infinite chains running along [0 1 0]. The chalcogens in both compounds form chalcogenide Q{sup 2-} and dichalcogenide (Q{sub 2}){sup 2-} anionic units. The optical analysis made on those compounds shows that both are semiconductors with band gap of 1.71 and 1.22 eV for Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 4}Sb{sub 2}Se{sub 11.75,} respectively. - Graphical Abstract: The crystal structure of Yb{sub 4}Sb{sub 2}S{sub 11} viewed along the [0 1 0]. Highlights: Black-Right-Pointing-Pointer Lanthanide chalcogenides. Black-Right-Pointing-Pointer Semiconductors. Black-Right-Pointing-Pointer Tunnel structures. Black-Right-Pointing-Pointer Lone-pair effects.

  8. Spectroscopic investigation of the chemical and electronic properties of chalcogenide materials for thin-film optoelectronic devices

    Science.gov (United States)

    Horsley, Kimberly Anne

    Chalcogen-based materials are at the forefront of technologies for sustainable energy production. This progress has come only from decades of research, and further investigation is needed to continue improvement of these materials. For this dissertation, a number of chalcogenide systems were studied, which have applications in optoelectronic devices, such as LEDs and Photovoltaics. The systems studied include Cu(In,Ga)Se2 (CIGSe) and CuInSe 2 (CISe) thin-film absorbers, CdTe-based photovoltaic structures, and CdTe-ZnO nanocomposite materials. For each project, a sample set was prepared through collaboration with outside institutions, and a suite of spectroscopy techniques was employed to answer specific questions about the system. These techniques enabled the investigation of the chemical and electronic structure of the materials, both at the surface and towards the bulk. CdS/Cu(In,Ga)Se2 thin-films produced from the roll-to-roll, ambient pressure, Nanosolar industrial line were studied. While record-breaking efficiency cells are usually prepared in high-vacuum (HV) or ultra-high vacuum (UHV) environments, these samples demonstrate competitive mass-production efficiency without the high-cost deposition environment. We found relatively low levels of C contaminants, limited Na and Se oxidation, and a S-Se intermixing at the CdS/CIGSe interface. The surface band gap compared closely to previously investigated CIGSe thin-films deposited under vacuum, illustrating that roll-to-roll processing is a promising and less-expensive alternative for solar cell production. An alternative deposition process for CuInSe2 was also studied, in collaboration with the University of Luxembourg. CuInSe2 absorbers were prepared with varying Cu content and surface treatments to investigate the potential to produce an absorber with a Cu-rich bulk and Cu-poor surface. This is desired to combine the bulk characteristics of reduced defects and larger grains in Cu-rich films, while maintaining

  9. 21 CFR 573.680 - Mineral oil.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Mineral oil. 573.680 Section 573.680 Food and... Listing § 573.680 Mineral oil. Mineral oil may be safely used in animal feed, subject to the provisions of this section. (a) Mineral oil, for the purpose of this section, is that complying with the...

  10. Effect of mineral processing wastewater on flotation of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-ming; LIU Run-qing; SUN Wei; QIU Guan-zhou

    2009-01-01

    The effects of mineral processing wastewater on sulfide minerals were investigated by flotation, infrared spectrometry and electrochemistry test. The results show that lead-concentrate water can improve the flotation of galena, while the sulfur-concentrate water has negative effect on flotation of galena compared with distilled water. The flotation behavior of pyrite is contrary to that of galena in three kinds of water. Infrared spectra indicate that the residual collector in the lead-concentrate water is beneficial to the formation of lead xanthate on the surface of galena. Electrochemistry results indicate that electrochemistry reaction on galena surface has apparent change. The anode polarization is improved and cathode polarization is depressed.

  11. Proton induced luminescence of minerals

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H.; Millan, A.; Calderon, T. [Depto. Geologia y Geoquimica, Universidad Autonoma de Madrid, Ctra. Colmenar, km. 15, 28049, Madrid (Spain); Beneitez, P. [Departamento Quimica Fisica Aplicada, Universidad Autonoma de Madrid Cantoblanco, Madrid (Spain); Ruvalcaba S, J.L. [lFUNAM, Circuito de la lnvestigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2008-07-01

    This paper presents a summary of Ionoluminescence (IL) for several minerals commonly found in jewellery pieces and/or artefacts of historical interest. Samples including silicates and non-silicates (native elements, halide, oxide, carbonate and phosphate groups) have been excited with a 1.8 MeV proton beam, and IL spectra in the range of 200- 900 nm have been collected for each one using a fiber optic coupled spectrometer. Light emissions have been related to Cr{sup 3+}, Mn{sup 2+} and Pr{sup 3+} ions, as well as intrinsic defects in these minerals. Results show the potential of IL for impurity characterization with high detection limits, local symmetry studies, and the study of the origin of minerals. (Author)

  12. Clay minerals in pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Tateo, F. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Argille, Tito Scalo, PZ (Italy)

    2000-07-01

    Clay minerals are fundamental constituents of life, not only as possible actors in the development of life on the Earth (Cairns-Smith and Hartman, 1986), but mainly because they are essential constituents of soils, the interface between the solid planet and the continental biosphere. Many, many authors have devoted themselves to the study of clays and clay minerals since the publication of the early modern studies by Grim (1953, 1962) and Millot (1964). In those years two very important associations were established in Europe (Association Internationale pour l'Etude des Argiles, AIPEA) and in the USA (Clay Mineral Society, CMS). The importance of these societies is to put together people that work in very different fields (agronomy, geology, geochemistry, industry, etc.), but with a common language (clays), very useful in scientific work. Currently excellent texts are being published, but introductory notes are also available on the web (Schroeder, 1998).

  13. Supercontinuum generation in a step-index chalcogenide fiber with AsSe2 core and As2S5 cladding

    Science.gov (United States)

    Gao, Weiqing; Xu, Qiang; Li, Xue; Zhang, Wei; Hu, Jigang; Li, Yuan; Chen, Xiangdong; Yuan, Zijun; Liao, Meisong; Li, Xia; Bi, Wanjun; Cheng, Tonglei; Suzuki, Takenobu; Ohishi, Yasutake

    2016-12-01

    We demonstrate the supercontinuum (SC) generation in a chalcogenide step-index fiber with AsSe2 core and As2S5 cladding. The characteristics of fiber are analyzed using the full-vectorial mode solver technique. The fiber has two zero-dispersion wavelengths at 2898 and 5140 nm. The evolving of SC spectra with fiber length and pump wavelength is investigated experimentally. The maximum SC range covering one octave from 1550 to 3300 nm is obtained when the 20 cm long fiber is pumped by 2000 nm pulses in normal dispersion region. The fiber can push forward the nonlinear application based on the stimulated Raman effect, stimulated Brillouin effect, four-wave mixing, supercontinuum generation, and so on in the mid-infrared waveband. The SCs are simulated by the nonlinear Schrödinger equation. The simulated results agree well with the experiments.

  14. Ge1Sb2Te4 Based Chalcogenide Random Access Memory Array Fabricated by 0.18-μm CMOS Technology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ting; SONG Zhi-Tang; FENG Gao-Ming; LIU Bo; WU Liang-Cai; FENG Song-Lin; CHEN Bomy

    2007-01-01

    Ge1Sb2Te4-based chalcogenide random access memory array, with a tungsten heating electrode of 260nm in diameter, is fabricated by 0.18-μm CMOS technology. Electrical performance of the device, as well as physical and electrical properties of Ge1Sb2Te4 thin film, is characterized. SET and RESET programming currents are 1.6 and 4.1 mA, respectively, when pulse width is 100ns. Both the values are larger than those of the Ge2Sb2 Te5-based ones with the same structure and contact size. Endurance up to 106 cycles with a resistance ratio of about 100 has been achieved.

  15. A Facile Method for the Synthesis Fluorescent Zinc Chalcogenide (ZnO, ZnS and ZnSe) Nanoparticles in PS and PMMA Polymer Matrix.

    Science.gov (United States)

    Hariharan, P S; Subhashini, N; Vasanthalakshmi, J; Anthony, Savarimuthu Philip

    2016-03-01

    A simple method for the synthesis of fluorescent zinc chalcogenide (ZnO, ZnS and ZnSe) nanoparticles directly in the transparent PMMA and PS polymer matrices were reported. Highly dispersed small spherical ZnO nanoparticles (3-5 nm) was obtained by hydrothermal reaction of PMMA/PS-Zn(acac)2H2O in toluene. ZnS and ZnSe nanoparticles were prepared by heterogeneous stirring of PMMA/PS-Zn(acac)2H2O in toluene with aqueous solution of thiourea or NaHSe. Interestingly, ZnO and ZnS-PMMA thin film showed strong fluorescence quenching upon exposure to ammonia.

  16. Metal Ions Mediated Morphology and Phase Transformation of Chalcogenide Semiconductor: From CuClSe2 Microribbon to CuSe Nanosheet.

    Science.gov (United States)

    Liu, Yong-Qiang; Wu, Hao-Di; Zhao, Yu; Pan, Ge-Bo

    2015-05-01

    Foreign ions are of significant importance in controlling and modulating the morphology of semiconductor nanocrystals during the colloidal synthesis process. Herein, we demonstrate the potential of foreign metal ions to simultaneously control the morphology and crystal phase of chalcogenide semiconductors. The results indicate that the introduction of Al(3+) ions can induce the structural transformation from monoclinic CuClSe2 microribbons (MRs) to klockmannite CuSe nanosheets (NSs) and the growth of large-sized CuSe NSs. The as-prepared micrometer-sized CuSe NSs exhibit a high-conducting behavior, long-term durability, and environment stability. The novel properties enable CuSe NSs to open up a bright prospect for printable electrical interconnects and flexible electronic devices.

  17. First principles calculations of structural, electronic and thermal properties of lead chalcogenides PbS, PbSe and PbTe compounds

    Indian Academy of Sciences (India)

    N Boukhris; H Meradji; S Amara Korba; S Drablia; S Ghemid; F El Haj Hassan

    2014-08-01

    The structural, electronic and thermal properties of lead chalcogenides PbS, PbSe and BeTe using full-potential linear augmented plane wave (FP-LAPW) method are investigated. The exchange–correlation energy within the local density approximation (LDA) and the generalized gradient approximation (GGA) are described. The calculated structural parameters are in reasonable agreement with the available experimental and theoretical data. The electronic band structure shows that the fundamental energy gap is direct (L–L) for all the compounds. Thermal effects on some macroscopic properties of these compounds are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the lattice constant, bulk modulus, heat capacity, volume expansion coefficient and Debye temperature with temperature and pressure are obtained successfully. The effect of spin–orbit interaction is found to be negligible in determining the thermal properties and leads to a richer electronic structure.

  18. Neutron diffraction study of structural transformations in ternary systems of HgSe sub 1 sub - sub x S sub x mercury chalcogenides at high pressure

    CERN Document Server

    Voronin, V I; Berger, I F; Glazkov, V P; Kozlenko, D P; Savenko, B N; Tikhomirov, S V

    2001-01-01

    The structure of the ternary systems of the HgSe sub 1 sub - sub x S sub x mercury chalcogenides is studied at high pressures up to 35 kbar. It is established that by increase in the pressure in the HgSe sub 1 sub - sub x S sub x there takes place the transition from the sphalerite type cubic structure to the cinnabar type hexagonal structure, which is accompanied by the jump-like change in the elementary cell volume and interatomic distances. The parameters of the elementary cell and positional parameters of the Hg and Se/S for the hexagonal phase of high pressure are determined. The existence of the two-phase state in the area of the phase transformation is determined

  19. Geochemistry and Minerality of Wine

    Science.gov (United States)

    Oze, C.; Horton, T. W.; Beaman, M.

    2010-12-01

    Kaolinite (Al2Si2O5(OH)4) and gibbsite (Al(OH)3) are capable of forming in a variety of environments including anthropogenic solutions such as wine. Here, we evaluate the geochemistry of twelve white wines in order to assess the potential relationship between kaolinite/gibbsite saturation and minerality, a common wine descriptor used to express the rock and/or soil character in the aromas and flavors of wines. Aluminum and Si concentrations ranged from 228-1,281 µg L-1 and 6,583-19,746 µg L-1, respectively, where Si and Al are the only elements to demonstrate positive covariance with minerality scores. Sulfur levels varied from 25,013-167,383 µg L-1 and show the strongest negative covariance with minerality scores. However, like all of the elements studied (Al, Si, Na, Mg, S, K, Ca, and Fe), these trends were not significantly different than random at the 95% confidence level. In contrast, the relative degrees of gibbsite/kaolinite saturation display strong positive covariance with minerality scores and these trends are not random at the greater than 95% confidence level. Overall, our tasters were able to accurately assess the degree of gibbsite/kaolinite saturation amongst the twelve wines based on the objective of assessing minerality. Although the wines were undersaturated with respect to gibbsite/kaolinite, geochemical modeling reveals that increasing the wines’ pHs from ~3.3 to 4.1-4.6 (which is achievable on the palate where saliva has a pH of 7.4) results in gibbsite/kaolinite oversaturation. By considering that minerality is a function of gibbsite/kaolinite saturation and decreasing S, the origin of minerality’s taste and chemical origin in wine with known physical standards becomes increasingly crystalline.

  20. Study of Third-Order Optical Nonlinearities of Se-Sn (Bi,Te) Quaternary Chalcogenide Thin Films Using Ti: Sapphire Laser in Femtosecond Regime

    Science.gov (United States)

    Yadav, Preeti; Sharma, Ambika

    2016-09-01

    The objective of the present research work is to study the nonlinear optical properties of quaternary Se-Sn (Bi,Te) chalcogenide thin films. A Z-scan technique utilizing 800 nm femtosecond laser source has been used for the determination of the nonlinear refractive index (n 2), two-photon absorption coefficient (β 2) and third-order susceptibility (χ (3)). In the measurement of n 2, an aperture is placed in the far field before the detector (closed aperture), while for the measurement of β 2, entire transmitted light is collected by the detector without an aperture (open aperture). Self-focusing has been observed in closed aperture transmission spectra. The appearance of the peak after the valley in this spectrum reflects the positive nonlinear refractive index. The calculated value of n 2 of the studied thin films varies from 1.06 × 10-12 cm2/W to 0.88 × 10-12 cm2/W. The compound-dependent behavior of n 2 is explained in this paper. We have also compared the experimental values of n 2 with the theoretically determined values, other compounds of chalcogenide glass and pure silica. The n 2 of the investigated thin films is found to be 3200 times higher than pure silica. The results of the open aperture Z-scan revealed that the value of β 2 of the studied compound is in the order of 10-8 cm/W. The behavior of two-photon absorption is described by means of the optical band gap (E g) of the studied compound. The variation in the figure-of-merit from 0.32 to 1.4 with varying Sn content is also reported in this paper. The higher value of nonlinearity makes this material advantageous for optical fibers, waveguides and optical limiting devices.

  1. Study of Third-Order Optical Nonlinearities of Se-Sn (Bi,Te) Quaternary Chalcogenide Thin Films Using Ti: Sapphire Laser in Femtosecond Regime

    Science.gov (United States)

    Yadav, Preeti; Sharma, Ambika

    2017-01-01

    The objective of the present research work is to study the nonlinear optical properties of quaternary Se-Sn (Bi,Te) chalcogenide thin films. A Z-scan technique utilizing 800 nm femtosecond laser source has been used for the determination of the nonlinear refractive index ( n 2), two-photon absorption coefficient ( β 2) and third-order susceptibility ( χ (3)). In the measurement of n 2, an aperture is placed in the far field before the detector (closed aperture), while for the measurement of β 2, entire transmitted light is collected by the detector without an aperture (open aperture). Self-focusing has been observed in closed aperture transmission spectra. The appearance of the peak after the valley in this spectrum reflects the positive nonlinear refractive index. The calculated value of n 2 of the studied thin films varies from 1.06 × 10-12 cm2/W to 0.88 × 10-12 cm2/W. The compound-dependent behavior of n 2 is explained in this paper. We have also compared the experimental values of n 2 with the theoretically determined values, other compounds of chalcogenide glass and pure silica. The n 2 of the investigated thin films is found to be 3200 times higher than pure silica. The results of the open aperture Z-scan revealed that the value of β 2 of the studied compound is in the order of 10-8 cm/W. The behavior of two-photon absorption is described by means of the optical band gap ( E g) of the studied compound. The variation in the figure-of-merit from 0.32 to 1.4 with varying Sn content is also reported in this paper. The higher value of nonlinearity makes this material advantageous for optical fibers, waveguides and optical limiting devices.

  2. New layered-type quaternary chalcogenides, Tl2PbMQ4 (M = Zr, Hf; Q = S, Se): structure, electronic structure, and electrical transport properties.

    Science.gov (United States)

    Sankar, Cheriyedath Raj; Assoud, Abdeljalil; Kleinke, Holger

    2013-12-16

    We have synthesized and characterized new thallium chalcogenides of the general formula Tl2PbMQ4 (M = Zr, Hf; Q = S, Se) from the constituent elements via high-temperature reaction conditions. These sulfides and selenides crystallize in the monoclinic crystal system (space group C2/c). The unit cell parameters refined from single-crystal X-ray diffraction data for Tl2PbZrS4 are a = 15.455(4) Å, b = 8.214(2) Å, c = 6.751(2) Å, β = 109.093(3)°, and V = 809.9(4) Å(3), with Z = 4. No corresponding tellurides were obtained from similar reaction conditions. The isostructural quaternary chalcogenides form a layered structure, composed of alternating metal and chalcogen layers. The latter are packed along the a axis as in the face-centered cubic packing (ABC), while the metal layers alternate between Tl layers and mixed Pb/Zr layers. All metal atoms are located in differently distorted Q6 octahedra, with the TlQ6 polyhedra being the least regular ones. Density functional theory based electronic structure calculations with inclusion of relativistic spin-orbit interactions predict (indirect) energy band gaps of 0.66 and 0.33 eV for Tl2PbZrS4 and Tl2PbHfSe4, respectively. Optical spectroscopy revealed significantly larger (direct) band gaps of 1.2 and 1.6 eV. The semiconducting character is in agreement with the charge-balanced formula (Tl(+))2Pb(2+)M(4+)(Q(2-))4. The electrical transport properties also show the semiconducting nature of these materials. For Tl2PbHfSe4, the Seebeck coefficient increases from +190 μV K(-1) at room temperature to +420 μV K(-1) at 520 K.

  3. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20140786Deng Zhenping(Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004,China);Yang Wen-qiong Application of Stripping Voltammetry with a Solid Amalgam Electrode for Determination of Copper in a Tracer and Groundwater Tracing Experiment(Rock and Mineral Analy-

  4. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152386 Hao Yuanfang(Shenyang Institute of Geology and Mineral Resources,CGS,Shenyang 110032,China);Xu Yingkui Determination of Calcium Oxide in Nickel Ores with EDTA Titration(Geology and Resources,ISSN1671-1947,CN21-1458/P,23(6),2014,p.580-582,2tables,6 refs.)

  5. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131550 Bai Jinfeng(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China);Bo Wei Determination of 36Elements in Geochemical Samples by High Resolution Inductively Coupled Plasma-Mass Spectrometry(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,31(5),2012,p.814

  6. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>20050704 Cheng Lin (Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China); Feng Songlin Analysis of Colored Elements in Ancient Colored Glaze by SRXRF (Rock and Mineral Analysis, ISSN0254-5357, CN11 -2131/TD, 23 (2), 2004, p. 113-116, 120, 3 illus. , 3 tables, 6 refs. )

  7. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20142093Chen Daohua(Guangzhou Marine Geological Survey,Guangzhou 510075,China);Diao Shaobo The Latest Progress of Geological Marine Testing Technology in China(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,32(6),2013,p.850-859,105refs.)Key words:chemical analysis,China

  8. KeyPathwayMinerWeb

    DEFF Research Database (Denmark)

    List, Markus; Alcaraz, Nicolas; Dissing-Hansen, Martin;

    2016-01-01

    We present KeyPathwayMinerWeb, the first online platform for de novo pathway enrichment analysis directly in the browser. Given a biological interaction network (e.g. protein-protein interactions) and a series of molecular profiles derived from one or multiple OMICS studies (gene expression...

  9. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070252 Chen Meilan (Biological and Environmental College, Zhejiang Shuren University, Hangzhou 310015, China); Li Li Study on Adsorption of Phenol by Modified Organobentonite (Rock and Mineral Analysis, ISSN0254-5357, CN11-2131/TD, 24(4), 2005, p.259-261, 267, 6 illus., 1 table, 11 refs.) Key words: bentonite, benzene, adsorption

  10. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    20160255 Wang Na(Tianjin Center of Geological Survey,China Geological Survey,Tianjin 300170,China);Teng Xinhua Determination of Low-Content Iron Carbonate in Stream Sediments by Flame Atomic Absorption Spectrometry with Aluminum Chloride Extraction(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,34(2),2015,p.229

  11. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20150874Chen Haidong(Inner Mongolia Institute of Geological Survey and Mineral Exploration,Hohhot 010010,China);Li Jiao Zircon U-Pb Dating of the Hypersthene-Plagioclase Granulite in Liangcheng Area of Central Inner Mongolia and Its Geological Significance(Geology in China,ISSN1000-3657,CN11-1167/P,41(4),2014,p.1136-1142,

  12. Leptin and bone mineral density

    DEFF Research Database (Denmark)

    Morberg, Cathrine M; Tetens, Inge; Black, Eva;

    2003-01-01

    Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg...

  13. Proceedings of XXIV international mineral processing congress

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dianzuo; Sun Chuan Yao; Wang Fu Liang; Zhang Li Cheng; Han Long (eds.)

    2008-07-01

    Topics covered in volume 1 include applied mineralogy, comminution, classification, physical separation, flotation chemistry, sulphide flotation, non-sulphide flotation and reagent in mineral industry. Volume 2 covers processing of complex ores, processing of industrial minerals and coal, solid liquid separation, dispersion and aggregation, process simulation, expert systems and control of mineral processing, biohydrometallurgy, and mineral chemical processing. Volume 3 contains powder technology, mineral materials, treatment and recycling for solid wastes, waste water treatment, secondary resource recovery, soil remediation, concentrator engineering and process design, and application of mineral processing in related industry. It includes a CD-ROM of the proceedings.

  14. Experimental study of the structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se by means of NQR and EPR spectroscopy

    Science.gov (United States)

    Bolebrukh, Olga; Sinyavsky, Nikolay; Korneva, Irina; Dobosz, Bernadeta; Ostafin, Michal; Nogaj, Boleslaw; Krzyminiewski, Ryszard

    2013-12-01

    The structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se has been studied by means of both NQR (nuclear quadrupole resonance) and EPR (electron paramagnetic resonance) spectroscopy. It is investigated that in the glasses of both systems the value of the electric field gradient at the resonating nuclei grows with increasing concentration of the clusters As2Se3 and Sb2Se3, thereby increasing the NQR resonance frequencies. It appears that for the Ge-As-Se system the structural transition from a two-dimensional to three-dimensional structure occurs at average coordination number bar r = 2.45. The EPR spectral parameters of glasses depend on the composition, the average coordination number and the temperature, and these are discussed. The effect of "ageing" for CGS (chalcogenide glassy semiconductors) of As-Sb-Se system due to partial crystallization of the sample is observed from the EPR spectra.

  15. The pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 at high pressure: a mechanism for the zinc blende to cinnabar reconstructive phase transition

    CERN Document Server

    Kozlenko, D P; Ehm, L; Hull, S; Savenko, B N; Shchennikov, V V; Voronin, V I

    2003-01-01

    The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by x-ray and neutron powder diffraction at pressures up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. A phenomenological model of this reconstructive phase transition based on a displacement mechanism is proposed. Analysis of the geometrical relationship between the zinc blende and the cinnabar phases has shown that the possible order parameter for the zinc blende-cinnabar structural transformation is the spontaneous strain e sub 4. This assignment agrees with the previously observed high pressure behaviour of the elastic constants of some mercury chalcogenides.

  16. U.S. Geological Survey Mineral Resources Program—Mineral resource science supporting informed decisionmaking

    Science.gov (United States)

    Wilkins, Aleeza M.; Doebrich, Jeff L.

    2016-09-19

    The USGS Mineral Resources Program (MRP) delivers unbiased science and information to increase understanding of mineral resource potential, production, and consumption, and how mineral resources interact with the environment. The MRP is the Federal Government’s sole source for this mineral resource science and information. Program goals are to (1) increase understanding of mineral resource formation, (2) provide mineral resource inventories and assessments, (3) broaden knowledge of the effects of mineral resources on the environment and society, and (4) provide analysis on the availability and reliability of mineral supplies.

  17. Aggregate and Mineral Resources - INDUSTRIAL_MINERALS_POINTS_IN: Industrial Mineral Data in Indiana (Indiana Geological Survey, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — INDUSTRIAL_MINERALS_POINTS_IN is a shapefile that shows the distribution of stratigraphic data for various industrial minerals in Indiana. These data were derived...

  18. Minería de datos con Oracle Data Miner

    OpenAIRE

    Fernández Ruiz, Benjamín

    2016-01-01

    La intención del proyecto es mostrar las diferentes características que ofrece Oracle en el campo de la minería de datos, con la finalidad de saber si puede ser una plataforma apta para la investigación y la educación en la universidad. En la primera parte del proyecto se estudia la aplicación “Oracle Data Miner” y como, mediante un flujo de trabajo visual e intuitivo, pueden aplicarse las distintas técnicas de minería (clasificación, regresión, clustering y asociación). Para mostrar la ej...

  19. Structure and Optical Properties of Polycrystalline InxSb30 – xSe70 (0 ≤ x ≤ 25 Chalcogenide Alloys

    Directory of Open Access Journals (Sweden)

    Shaveta Sharma

    2016-06-01

    Full Text Available The spectroscopic studies of various physical properties of glassy and polycrystalline chalcogenide alloys are important due to their importance as active materials in various solid state devices. The composition dependence of these properties are explained on the basis of coordination number, but the splitting of this effect from the nature of additive is imperative for furthering the understanding of these systems. In the present work, the structural and spectroscopic investigations of melt quenched bulk In-Sb-Se chalcogenide alloys have been studied by XRD, RAMAN and optical spectroscopic techniques. The XRD study reveals the polycrystalline nature of the samples. The composition was analysed using the energy dispersive X-ray spectroscopy technique. The XRD study reveals the crystallization of Sb2Se3 and β-In2Se3 phases while the increase in the intensity for β-In2Se3 phase has been observed with the increase in indium content. The RAMAN spectra also reveal the formation of chalcogenide based Sb and In structural units. The diffused reflectance spectrum was used to calculate the optical absorption in 800-1500 nm spectral region and used to study the composition dependence of the optical gap in these samples. The results have been discussed in conjunction with the heterogeneous phases; density of defect states; electronegativity and average mean bond energy for these polycrystalline alloys.

  20. ARC Code TI: sequenceMiner

    Data.gov (United States)

    National Aeronautics and Space Administration — The sequenceMiner was developed to address the problem of detecting and describing anomalies in large sets of high-dimensional symbol sequences. sequenceMiner works...

  1. Mineral operations outside the United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Mineral facilities and operations outside the United States compiled by the National Minerals Information Center of the USGS. This representation combines source...

  2. Mineral Operations of Latin America and Canada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries...

  3. Miscellaneous Industrial Minerals Operations - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  4. Characterization of biological mineralization in vitro

    NARCIS (Netherlands)

    Huitema, L.F.A.

    2006-01-01

    Mineralization is an essential requirement for normal skeletal development, which is generally accomplished through the function of two cell types, osteoblasts and chondrocytes. Soft tissues do not mineralize under normal conditions, but under certain pathological conditions some tissues like articu

  5. APPLICATION OF MICROBIAL TECHNOLOGY TO MINERAL PROCESSING

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The application of microbial technology to mineral processing has been reviewed with respect to the bioleaching of metals from minerals, the influence of biotreatment on flotation, the biobene ficiation of nonmetallic minerals, and the biotreatment for mine waste reclamation.The application of microbial technology to mineral processing has shown the advantages of high efficiency, low energy and reagent consumption, low capital and operating costs, and low pollution of the environment.

  6. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  7. Bolter miners for longwall development

    Energy Technology Data Exchange (ETDEWEB)

    Leeming, J.; Flook, S. [Joy Mining Machinery Ltd., Nottingham (United Kingdom); Altounyan, P. [Rock Mechanics Technology Ltd., Derby (United Kingdom)

    2001-11-08

    Rapid entry drivage systems are now being applied in European mining conditions with major advantages, not only in terms of drivage rates, costs and longwall productivity, but also with improved safety. This is being achieved through the introduction of bolter miner systems in which the early installation of high strength rockbolts is fully integrated with the drivage system and all ancillary operations. These new systems are fully described with examples of applications in European conditions and procedures for design of rockbolt patterns. (orig.) [German] Schnelle Streckenvortriebssysteme, die jetzt unter typisch europaeischen Bergbaubedingungen eingefuehrt werden, bringen grosse Vorteile, nicht nur hinsichtlich einer Verbesserung der Vortriebsgeschwindigkeiten, Auffahrkosten und Strebleistungen, sondern auch aufgrund des erhoehten Sicherheitsniveaus. Der Erfolg dieses Vortriebsverfahrens kann auf die Einfuehrung des Bolter Miner Systems zurueckgefuehrt werden. (orig.)

  8. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122362 Cai Shuwei ( Nanjing Institute of Geology and Mineral Resources,Nanjing 210016,China );Zhu Jiaping Evaluating on Uncertainty of Determination of Manganese Contents in Groundwater by Inductively Coupled Plasma Atomic Emission Spectrometry ( Resources Survey & Environment,ISSN1671-4814,CN32-1640 / N,32 ( 4 ), 2011,p.307-310,2tables,8refs. ) Key words:inductively coupled plasma atomic emission spectroscopy,manganese

  9. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20101621 Chen Heping (Nanyang Geology Testing & Research Center of Henan Province, Nanyang 473000, China); Sha Yanmei Simultaneous Determination of Major and Minor Elements in Carbonates by Inductively Coupled Plasma-Atomic Emission Spectrometry with Multi-direction Viewing Mode (Rock and Mineral Analysis, ISSN0254-5357, CN11-2131/TD, 28(4), 2009, p.367-369, 5 tables, 10 refs.)

  10. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070970 Cheng Jian(Center of Analysis and Testing,Hunan Zhuye Torch Metals Co., Ltd.,Zhuzhou 412004,China)Direct Deter- mination of Lead in Refined Indium by Flume Atomic Absorption Spectrometry (Rock and Mineral Analysis,ISSN 0254- 5357,CN11-2131/TD,25(1),2006,p.91 -92,94,1 illus.,7 tables,5 refs.) Key words:lead,atomic absorption

  11. Mineral zircon : A novel thermoluminescence geochronometer

    NARCIS (Netherlands)

    Van Es, HJ; Vainshtein, DI; De Meijer, RJ; Den Hartog, HW; Donoghue, JF; Rozendaal, A

    2002-01-01

    Mineral zircon contains trace amounts (typically 10-1000 ppm) of the alpha-emitters uranium and thorium, which irradiate this mineral internally. This outstanding feature of zircon turns out to be extremely useful when this mineral is applied as a thermoluminescence (TL) dating medium, because the b

  12. 43 CFR 8.5 - Mineral rights.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Mineral rights. 8.5 Section 8.5 Public... INTERIOR AND OF THE ARMY RELATIVE TO RESERVOIR PROJECT LANDS § 8.5 Mineral rights. Mineral, oil and gas rights will not be acquired except where the development thereof would interfere with project...

  13. Mineral Status of Myocardial Sarcocystosis

    Directory of Open Access Journals (Sweden)

    GA Kojouri

    2011-06-01

    Full Text Available Background: The role of minerals on parasite persistency and the interaction between minerals and animal responses to the parasite infestation is not clear. For these reasons, the present re­search was aimed to compare copper, zinc and iron status in sheep with parasitic myocarditis and healthy ones in 2009.Methods: Blood and heart tissue samples were collected from 145 slaughtered sheep and histopa­thological findings were confirmed as myocardial sarcocystosis in 27 cases. Serum and tis­sue mineral level were determined by atomic absorption spectroscopy. Data were analyzed by Sig­mastat program, using One Way Analysis of Variance (ANOVA at the level of P<0.05.Results: Myocardial sarcocystosis significantly increase myocardial concentration of Cu, Zn and Fe (P<0.05.Conclusion: These findings may explain the role of copper, zinc and iron in parasite persistency and may discuss the pathogenesis of sarcocystosis, which relates to evocate mentioned micronutri­ent to cardiac muscle.

  14. Is Struvite a Prebiotic Mineral?

    Directory of Open Access Journals (Sweden)

    Matthew A. Pasek

    2013-04-01

    Full Text Available The prebiotic relevance of mineral struvite, MgNH4PO4·6H2O, was studied experimentally as a phosphorylating reagent and, theoretically, to understand the geochemical requirements for its formation. The effectiveness of phosphorylation by the phosphate mineral, monetite, CaHPO4, was also studied to compare to the efficiency of struvite. The experiments focused on the phosphorylation reactions of the minerals with organic compounds, such as nucleosides, glycerol and choline chloride, and heat at 75 °C for about 7–8 days and showed up to 28% phosphorylation of glycerol. In contrast, the compositional requirements for the precipitation of struvite are high ammonium and phosphate concentrations, as well as a little Ca2+ dissolved in the water. Combined, these requirements suggest that it is not likely that struvite was present in excess on the early Earth to carry out phosphorylation reactions. The present study focuses on the thermodynamic aspects of struvite formation, complementing the results given by Orgel and Handschuh (1973, which were based on the kinetic effects.

  15. Is Struvite a Prebiotic Mineral?

    Science.gov (United States)

    Gull, Maheen; Pasek, Matthew A.

    2013-01-01

    The prebiotic relevance of mineral struvite, MgNH4PO4·6H2O, was studied experimentally as a phosphorylating reagent and, theoretically, to understand the geochemical requirements for its formation. The effectiveness of phosphorylation by the phosphate mineral, monetite, CaHPO4, was also studied to compare to the efficiency of struvite. The experiments focused on the phosphorylation reactions of the minerals with organic compounds, such as nucleosides, glycerol and choline chloride, and heat at 75 °C for about 7–8 days and showed up to 28% phosphorylation of glycerol. In contrast, the compositional requirements for the precipitation of struvite are high ammonium and phosphate concentrations, as well as a little Ca2+ dissolved in the water. Combined, these requirements suggest that it is not likely that struvite was present in excess on the early Earth to carry out phosphorylation reactions. The present study focuses on the thermodynamic aspects of struvite formation, complementing the results given by Orgel and Handschuh (1973), which were based on the kinetic effects. PMID:25369744

  16. [Legal aspects of mineral waters].

    Science.gov (United States)

    Callipo, C

    1976-01-01

    The Author takes up the subject of the report in order to carry out a comprehensive legal recognition of the mineral water regulations in Italy and emphasizes that in this field the results of scientific conclusions, or rather of the various scientific branches (medical hydrology, microbiology, chemics, hydrogeology, medical clinics, pharmacology, etc.) supply a cognitive support to the legislator and the substantial contents to the legal standards. He therefore illustrates the two main outlines of the rules, i.e. the hygienic sanitary one and the mineral one: such lay-out is subsequently related to the implementation of the Regions on one hand and to the enforcement of CEE-rules on the other. This has led to the fact that the hygienic-sanitary legislation was confirmed to the State while the mineral one was transferred to the Regions. After having shown up contrasts and expressed the necessity of clearness and uniformity of rules and criteria, the Author connects these requirements mainly with the implementation of hygienic-sanitary surveillance and consequently with the evaluation of the banal bacterical contents under the point of view of merit--i.e. the rules should include the probative results of science--as well as from a point of view of coordinated allotments of competence by the various organisms.

  17. Characterization of Atomic Structure, Relaxation and Phase Transformation Mechanisms in Bulk and Thin Film Amorphous Chalcogenides and Gallium Antimonide

    Science.gov (United States)

    Edwards, Trenton Gerard

    This dissertation details the characterization of the atomic structure, relaxation processes and phase transformation mechanisms in a variety of chalcogenide (selenides and tellurides) and other non-oxide (Ga-Sb alloys) glasses which are highly relevant to optoelectronic and phase change memory applications. One of the principal goals of these studies is to develop a fundamental, atomistic understanding of the structure-property relationships in these materials. Variable temperature Raman spectroscopy is used to the study the structure and its temperature dependent relaxation in GexSe100-x glasses and supercooled liquids with x ≤ 33.33 %. It is shown that the compositional dependence of the relative fractions of the edge- and corner-shared GeSe4 tetrahedra is fully consistent with a structural model based on random connectivity between the tetrahedral and chain elements. Temperature-dependent structural changes involve a progressive conversion of edge-shared to corner shared GeSe4 tetrahedra with decreasing equilibration temperature. The time scale of this structural conversion agrees with both enthalpy and shear relaxation near the glass transition. The temperature dependent change in the edge- vs. corner- sharing tetrahedral speciation is shown to be related to the production of configurational entropy, indicating a connection between structural relaxation, configurational entropy, and viscous flow. A combination of Raman and 77Se nuclear magnetic resonance (NMR) spectroscopy is applied to study the structure of a series of Se-deficient GexSe100-x glasses, with 42 ≥ x ≥ 33.33. Considerable violation of chemical order in the nearest-neighbor coordination environments of the constituent atoms is observed in the stoichiometric GeSe2 glass. On the other hand, the presence of a random distribution of Ge-Ge bonds can be inferred in the Se-deficient glasses. Furthermore, the results of this study conclusively indicate that the structure of these glasses is

  18. Mineral resource of the month: vermiculite

    Science.gov (United States)

    Tanner, Arnold O.

    2014-01-01

    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  19. Sorption of pesticides to aquifer minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite......, goethite, lepidocrocite). Selected pesticides are: atrazine, isoproturon, mecoprop, 2,4-D, and bentazone. The results demonstrate that pesticides adsorb to pure mineral surfaces. However, the size of the adsorption depends on the type of pesticide and the type of mineral....

  20. Sodium bicarbonated mineral water decreases postprandial lipaemia in postmenopausal women compared to a low mineral water

    OpenAIRE

    S. Schoppen; Pérez Granados, Ana M.; Carbajal, A.; Sarriá, Beatriz; Sánchez-Muniz, F. J.; J. A. Gómez-Gerique; Vaquero, M. Pilar

    2005-01-01

    The role of bicarbonated mineral waters on lipid metabolism and lipoprotein concentrations in man has scarcely been investigated. The present study aimed to investigate whether drinking sodium bicarbonated mineral water affects postprandial cholesterol and triacylglycerol metabolism in postmenopausal women. In a three-way, randomised, crossover study, eighteen healthy postmenopausal women consumed two sodium bicarbonated mineral waters (bicarbonated mineral water 1 and bicarbonated mineral wa...

  1. Quantitative Prediction for Deep Mineral Exploration

    Institute of Scientific and Technical Information of China (English)

    Zhao Pengda; Cheng Qiuming; Xia Qinglin

    2008-01-01

    On reviewing the characteristics of deep mineral exploration, this article elaborates on the necessity of employing quantitative prediction to reduce uncertainty. This is caused by complexity of mineral deposit formational environments and mineralization systems as increase of exploration depth and incompleteness of geo-information from limited direct observation. The authors wish to share the idea of "seeking difference" principle in addition to the "similar analogy" principle in deep mineral exploration, especially the focus is on the new ores in depth either in an area with discovered shallow mineral deposits or in new areas where there are no sufficient mineral deposit models to be compared. An on-going research project, involving Sn and Cu mineral deposit quantitative prediction in the Gejiu (个旧) area of Yunnan (云南) Province, China, was briefly introduced to demonstrate how the "three-component" (geoanomaly-mineralization diversity-mineral deposit spectrum) theory and non-linear methods series in conjunction with advanced GIS technology, can be applied in multi-scale and multi-task deep mineral prospecting and quantitative mineral resource assessment.

  2. Electronic structure of layered quaternary chalcogenide materials for band-gap engineering: The example of Cs2MIIM3IVQ8

    Science.gov (United States)

    Besse, Rafael; Sabino, Fernando P.; Da Silva, Juarez L. F.

    2016-04-01

    Quaternary chalcogenide materials offer a wide variety of chemical and physical properties, and hence, those compounds have been widely studied for several technological applications. Recently, experimental studies have found that the chalcogenide Cs2MIIM3IVQ8 family (MII = Mg , Zn , Cd , Hg , MIV = Ge , Sn and Q = S , Se , Te ), which includes 24 compounds, yields a wide range of band gaps, namely, from 1.07 to 3.4 eV, and hence, they have attracted great interest. To obtain an improved atomistic understanding of the role of the cations and anions on the physical properties, we performed a first-principles investigation of the 24 Cs2MIIM3IVQ8 compounds employing density functional theory within semilocal and hybrid exchange-correlation energy functionals and the addition of van der Waals corrections to improve the description of the weakly interacting layers. Our lattice parameters are in good agreement with the available experimental data (i.e., 11 compounds), and the equilibrium volume increases linearly by increasing the atomic number of the chalcogen, which can be explained by the increased atomic radius of the chalcogen atoms from S to Te . We found that van der Waals corrections play a crucial role in the lattice parameter in the stacking direction of the Cs2MIIM3IVQ8 layers, while the binding energy per unit area has similar magnitude as obtained for different layered materials. We obtained that the band gaps follow a linear relation as a function of the unit cell volume, which can be explained by the atomic size of the chalcogen atom and the relative position of the Q p states within the band structure. The fundamental and optical band gaps differ by less than 0.1 eV. The band gaps obtained with the hybrid functional are in good agreement with the available experimental data. Furthermore, we found from the Bader analysis, that the Coulomb interations among the cations and anions play a crucial role on the energetic properties.

  3. Decorin modulates matrix mineralization in vitro

    Science.gov (United States)

    Mochida, Yoshiyuki; Duarte, Wagner R.; Tanzawa, Hideki; Paschalis, Eleftherios P.; Yamauchi, Mitsuo

    2003-01-01

    Decorin (DCN), a member of small leucine-rich proteoglycans, is known to modulate collagen fibrillogenesis. In order to investigate the potential roles of DCN in collagen matrix mineralization, several stable osteoblastic cell clones expressing higher (sense-DCN, S-DCN) and lower (antisense-DCN, As-DCN) levels of DCN were generated and the mineralized nodules formed by these clones were characterized. In comparison with control cells, the onset of mineralization by S-DCN clones was significantly delayed; whereas it was markedly accelerated and the number of mineralized nodules was significantly increased in As-DCN clones. The timing of mineralization was inversely correlated with the level of DCN synthesis. In these clones, the patterns of cell proliferation and differentiation appeared unaffected. These results suggest that DCN may act as an inhibitor of collagen matrix mineralization, thus modulating the timing of matrix mineralization.

  4. Mineralization of Carbon Dioxide: Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, V; Soong, Y; Carney, C; Rush, G; Nielsen, B; O' Connor, W

    2015-01-01

    CCS research has been focused on CO2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO2 mineralization. 2

  5. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110144 Hu Lan(Anhui Institute of Geological Experiment,Hefei 230001,China);Liu Yueyou Determination of Micro-amount of Bismuth in Polymetallic Ores by Hydride Generation-Atomic Fluorescence Spectrometry with Alkaline Mode(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(1),2010,p.87-88,2 tables,10 refs.)Key words:atomic fluorescence spectrometry,bismuthA method for the determination of micro-amount of bismuth in polymetallic ores by hydride gen

  6. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20150204 Abaydulla Alimjan(Department of Chemistry and Environmental Sciences,Kashgar Teachers College,Kashgar 844006,China);Cheng Chunying Non-Metallic Element Composition Analysis of Non-Ferrous Metal Ores from Oytagh Town,Xinjiang(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,33(1),2014,p.44-50,5illus.,4tables,28refs.)Key words:nonferrous metals ore,nonmetals,chemical analysis,thermogravimetric analysis Anions in non-ferrous ore materials

  7. Mineral Resource Information System for Field Lab in the Osage Mineral Reservation Estate

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, H.B.; Johnson, William I.

    1999-04-27

    The Osage Mineral Reservation Estate is located in Osage County, Oklahoma. Minerals on the Estate are owned by members of the Osage Tribe who are shareholders in the Estate. The Estate is administered by the Osage Agency, Branch of Minerals, operated by the U.S. Bureau of Indian Affairs (BIA). Oil, natural gas, casinghead gas, and other minerals (sand, gravel, limestone, and dolomite) are exploited by lessors. Operators may obtain from the Branch of Minerals and the Osage Mineral Estate Tribal Council leases to explore and exploit oil, gas, oil and gas, and other minerals on the Estate. Operators pay a royalty on all minerals exploited and sold from the Estate. A mineral Resource Information system was developed for this project to evaluate the remaining hydrocarbon resources located on the Estate. Databases on Microsoft Excel spreadsheets of operators, leases, and production were designed for use in conjunction with an evaluation spreadsheet for estimating the remaining hydrocarbons on the Estate.

  8. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110887 Chen Yong(College of Geo-Resources and Information,China University of Petroleum,Qingdao 266555,China);Ge Yunjin Experimental Study on the Modes of Hydrocarbon-Bearing Inclusion Trapped in Carbonate Rock Reservoirs(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(3),2010,p.217-220,1 illus.,16 refs.,with English abstract)Key words:petroleum products,organic inclusion,carbonates20110888 Cheng Zhizhong(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China);Gu Tiexin Preparation of Nine Iron Ore Reference Materials of GFe-1~GFe-9(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(3),2010,p.305-308,5 tables,13 refs.)Key words:iron ores,type specimens Nine standard reference iron ore samples of GFe-1~GFe-9 were developed.The concentrations of TFe of the samples ranged from 20.17% to 66.87%,which covered a wide iron concentration range from concentrated iron ore powder to poor iron ores and can meet the needs for iron ore exploration and ore-dressing.Powder XRF technique was used for homogeneity test and the analytical results indicated that all elements tested were in good homogeneity.

  9. Mineral fibre persistence and carcinogenicity.

    Science.gov (United States)

    McDonald, J C

    1998-10-01

    Epidemiological research during the past 40 years has demonstrated with increasing clarity that amphibole asbestos fibres--crocidolite, amosite and tremolite--are more carcinogenic than chrysotile. A smaller number of well-controlled studies using lung burden analyses, while adding to the specificity of this conclusion, have shown that amphibole fibres also differ from chrysotile in being far more durable and biopersistent in lung tissue. Analyses of mesothelioma and lung cancer in a large cohort of Canadian chrysotile miners and millers have recently shown that the low-level presence of fibrous tremolite in these mines, rather than the chrysotile, may well be responsible. The high risk of lung cancer, but not of mesothelioma, in the chrysotile textile industry remains anomalous and cannot be explained in this way. These various findings are directly relevant to the choice of the experimental methods which should be used for screening man-made fibres for industrial use. Although it is clear that biopersistence is a major determinant of cancer risk in animals, and perhaps also in man, other factors affecting the biological activity of mineral fibres may also be important.

  10. ac conductivity and dielectric properties of amorphous Se{sub 80}Te{sub 20-x}Ge{sub x} chalcogenide glass film compositions

    Energy Technology Data Exchange (ETDEWEB)

    Hegab, N.A. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)], E-mail: abir_net_2005@hotmail.com; Afifi, M.A.; Atyia, H.E.; Farid, A.S. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2009-05-27

    Thin films of the prepared Se{sub 80}Te{sub 20-x}Ge{sub x} (x = 5, 7 and 10 at.%) were prepared by thermal evaporation technique. X-ray diffraction patterns showed that the films were in amorphous state. The ac conductivity and dielectric properties of the investigated film compositions were studied in the frequency range 0.1-100 kHz and in temperature range (303-373 K). The experimental results indicated that the ac conductivity and the dielectric properties depended on the temperature and frequency. The ac conductivity is found to obey the {omega}{sup s} law, in accordance with the hopping model, s is found to be temperature dependent (s < 1) and its value goes down as the temperature is increased. The temperature dependence of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping (CBH) model. Values of dielectric constant {epsilon}{sub 1} and dielectric loss {epsilon}{sub 2} were found to decrease with frequency and increase with temperature. The maximum barrier height W{sub m}, calculated from dielectric measurements according to Guintini equation, agrees with that proposed by the theory of hopping over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized states was estimated for the studied film compositions. The variation of the studied properties with Ge content was also investigated.

  11. External temperature and pressure effects on thermodynamic properties and mechanical stability of yttrium chalcogenides YX (X=S, Se and Te)

    Energy Technology Data Exchange (ETDEWEB)

    Seddik, T. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Bouhemadou, A.; Guechi, N. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif, 19000 Setif (Algeria); Sayede, A. [Université Lille Nord de France, F-59000 Lille (France); Université-Artois, UCCS, F-62300 Lens (France); CNRS, UMR 8181, F-59650 Villeneuve d’Ascq (France); Varshney, D. [Materials Science Laboratory, School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001, Madhya Pradesh (India); Al-Douri, Y. [Institute of Nono Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Reshak, A.H. [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Bin-Omran, S. [Department of Physics and Astronomy, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia)

    2013-11-01

    The full potential linearized augmented plane wave method within the framework of density functional theory is employed to investigate the structural, thermodynamic and elastic properties of the yttrium chalcogenides (YX: X=S, Se, and Te) in their low-pressure phase (Fm3{sup ¯}m) and high-pressure phase (Pm3{sup ¯}m). The exchange-correlation potential is treated with the generalized gradient approximation of Perdew–Burke–Ernzerhof (GGA-PBE). Temperature dependence of the volume and both adiabatic and isothermal bulk moduli is predicted for a temperature range from 0to1200K for the both phases of the herein considered materials. Furthermore, we have analyzed the thermodynamic properties such as the heat capacities, C{sub V} and C{sub P}, thermal expansion, α, and Debye temperature, Θ{sub D,} under variable pressure and temperature. We have calculated the isothermal elastic constants C{sub ij}{sup T} of the YX monochalcogenides in both NaCl-B1 and CsCl-B2 phases at zero pressure and a temperature range 0−1200K. The results show that rare earth yttrium monochalcogenides are mechanically stable at high temperature. The elastic anisotropy of all studied materials in the two phases has been studied using three different methods.

  12. Effect of Film Thickness on the Optical Parameters and Electrical Conductivity of Te10Ge10Se77Sb3 Chalcogenide Glass

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Several thin films of Te10Ge10Se77Sb3 chalcogenide glass of different thicknesses (250 nm to 400 nm) were prepared by thermalevaporation under vacuum of 133×10-6 Pa (10-6torr). X- ray diffraction analysis showed the amorphicity of the preparedfilms which become partially crystalline by annealing. Transmittance and reflectance measurements in the spectral range of200 nm to 2500 nm have been carried out at normal incidence. The analysis of the absorption coefficient data showed theexistence of indirect transition for the photon energy E in the range 1~3 eV and direct transition for E>3 eV. From thedetermination of the optical constants (n, k), the dispersion of the refractive index has anomalous behaviour in the region ofthe fundamental absorption edge, and followed by the single- effective oscillator approach. The investigated optical parameterssuch as the optical energy gap Eopt, the high frequency dielectric constant εoo, the oscillator position λo, and the oscillatorstrength So, were significantly affected by the film thickness. The characteristic energy gap obtained from the conductivitymeasurements is nearly half the value of that obtained from the optical data as in the case of thickness 400 nm. The activationenergy is 0.65 eV and the indirect optical gap is 1.32 eV.

  13. Structure and second-order nonlinearity of GeS2-Ga2S3-X2S3 (X=P,As,Sb) chalcogenide glasses

    Institute of Scientific and Technical Information of China (English)

    GONG Yue-qiu; GUO Hai-tao; ZHAO Xiu-jian

    2006-01-01

    To find new chalcogenide glass possessing larger second-order non-linearity,glasses with compositions Ge-Ga-X-S (X=P,As,Sb) were prepared via melt quenching technique. The amorphous nature of all the compositions of the as-quenched glasses was confirmed by X-ray diffraction(XRD). The glassy thermal properties of the as-quenched glasses were established by differential thermal analyses(DTA). The glass structure was studied by RAMAN spectra and the second order nonlinearity was studied by the Maker Fringe method after the electron beam poling(EBP) and electric/temperature field poling(ETFP) respectively. Additions of various pnicogen atoms into the Ge-Ga-S glasses lead to the difference in the second order nonlinearity of the glass. It's found that glasses with different structures result in different SHG intensities,and even more,a large second order nonlinear susceptibility c(2) of about 9 pm/V was obtained for all the glasses and the reasons for such a large susceptibility were analyzed.

  14. New Intermetallic Ternary Phosphide Chalcogenide AP2-xXx (A = Zr, Hf; X = S, Se) Superconductors with PbFCl-Type Crystal Structure

    Science.gov (United States)

    Kitô, Hijiri; Yanagi, Yousuke; Ishida, Shigeyuki; Oka, Kunihiko; Gotoh, Yoshito; Fujihisa, Hiroshi; Yoshida, Yoshiyuki; Iyo, Akira; Eisaki, Hiroshi

    2014-07-01

    We have synthesized a series of intermetallic ternary phosphide chalcogenide superconductors, AP2-xXx (A = Zr, Hf; X = S, Se), using the high-pressure synthesis technique. These materials have a PbFCl-type crystal structure (space group P4/nmm) when x is greater than 0.3. The superconducting transition temperature Tc changes systematically with x, yielding dome-like phase diagrams. The maximum Tc is achieved at approximately x = 0.7, at which point the Tc is 6.3 K for ZrP2-xSex (x = 0.75), 5.5 K for HfP2-xSex (x = 0.7), 5.0 K for ZrP2-xSx (x = 0.675), and 4.6 K for Hfp2-xSx (x = 0.5). They are typical type-II superconductors and the upper and lower critical fields are estimated to be 2.92 T at 0 K and 0.021 T at 2 K for ZrP2-xSex (x = 0.75), respectively.

  15. Enhancement in CO2 Adsorption Capacity and Selectivity in the Chalcogenide Aerogel CuSb2S4 by Post-synthetic Modification with LiCl

    KAUST Repository

    Ahmed, Ejaz

    2015-09-11

    The new chalcogel CuSb2S4 was obtained by reacting Cu(OAc)2·H2O with KSbS2 in a water/formamide mixture at room temperature. In order to modify the gas adsorption capacity the synthesized CuSb2S4 aerogel was loaded with different amounts of LiCl. CO2 adsorption measurements on the CuSb2S4 aerogel before and after treatment with LiCl showed more than three times increased uptake of the LiCl-modified chalcogel. The selectivities of the gas pairs CO2/H2 and CO2/CH4 in the LiCl-treated chalcogel are 235 and 105 respectively and amongst the highest reported for chalcogenide-based aerogels. In comparison with other porous materials like zeolites, activated carbon and most of the Metal Organic Frameworks (MOFs) or Porous Organic Frameworks (POFs), our synthesized aerogels show good air and moisture stability. Although, the CO2 storage capacity of our aerogels is relatively low, however the selectivity of CO2 over H2 or CH4 in LiCl-loaded aerogels are higher than in zeolites, activated carbon as well as some MOFs like Cu-BTC and MOF-5 etc.

  16. Mineral physics and mineral chemistry at the Australian National University

    Science.gov (United States)

    Jackson, Ian

    Research at the Australian National University (ANU) in Canberra into the physics and chemistry of minerals is being actively carried out by a number of different research groups within the Research School of Earth Sciences (RSES), the Research School of Chemistry (RSC), and the Department of Geology. The research schools form part of the Institute of Advanced Studies, which is a national center for research and postgraduate training established by the Australian Government in 1946. The Institute of Advanced Studies seeks to ensure flexibility in its approach to research by maintaining an unusually high ratio (>1) of nontenured to tenured staff. Two types of nontenured appointment are available: postdoctoral fellowships of 1-2 yr duration and research fellowships tenable for 3-5 yr. The Department of Geology, as part of the Faculty of Science, is responsible for the provision of undergraduate education in geology, in addition to its role in research and postgraduate training.

  17. The nanosphere iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxyl mineral such as 'green rust', or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable meaghemite (gamma-Fe203) by mild heat treatment and then to nanophase hematite (aplha-Fe203) by extensive heat treatment. Their chemical reactivity offers a plausible mechanism for the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The mode of formation of these (nanophase) iron oxides on Mars is still unknown.

  18. Regulation of bone mineral loss during lactation

    Science.gov (United States)

    Brommage, R.; Deluca, H. F.

    1985-01-01

    The effects of varyng dietary calcium and phosphorous levels, vitamin D deficiency, oophorectomy, adrenalectomy, and simultaneous pregnancy on bone mineral loss during lactation in rats are studied. The experimental procedures and evaluations are described. The femur ash weight of lactating and nonlactating rats are calculated. The data reveals that a decrease in dietary calcium of 0.02 percent results in an increased loss of bone mineral, an increase in calcium to 1.4 percent does not lessen bone mineral loss, and bone mineral loss in vitamin D deficient rats is independent of calcium levels. It is observed that changes in dietary phosphorous level, oophorectomy, adrenalectomy, and simultaneous pragnancy do not reduce bone mineral loss during lactation. The analysis of various hormones to determine the mechanism that triggers bone mineral loss during lactation is presented.

  19. Mining and minerals policy: 1976 bicentennial edition

    Energy Technology Data Exchange (ETDEWEB)

    1976-07-01

    The report is organized into three basic parts. The first part, the Executive Summary, provides a brief description of the major topics and lists the issues and recommendations. The report then is divided into two sections. Section I, Summary, is comprised of three chapters: Increased Energy Security; Metals and Nonmetallic Minerals; and Trends and Events. Section II, Issues in Energy and Minerals Policy, is comprised of seven chapters: Federal Leasing; The Federal Role in Reducing the Fiscal Impacts of Energy Development; Availability of Federal Lands for Mineral Exploration and Development; Environmental Issues and the Mineral Industry; Developments in International Minerals Trade and Investment; Ocean Mining; and The Development of New Tools for Energy and Minerals Policy Analysis. (MCW)

  20. Calculation of topological connectivity index for minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Topological method was applied firstly to calculate the topological connectivity index of minerals (TCIM). The reciprocal of effective atomic refractivity of metal dement in minerals was chosen as its valence. The reasonability of TCIM as an activity criterion was tested through comparison of TCIM with two kinds of dectronegativity parameter, i.e. ionic percentage and energy criteria of Yang's electronegativity, solubility product, energy criterion according to the gen eralized perturbation theory and adsorption of flotation reagents on the surface of minerals. The results indicated that TCIM is an effective structural parameter of minerals to study the structure-activity relationship. In addition, different mineral is of different TCIM value, so TCIM brings about convenience in comparison of flotation activity for minerals.

  1. Defective skeletal mineralization in pediatric CKD.

    Science.gov (United States)

    Wesseling-Perry, Katherine

    2015-04-01

    Although traditional diagnosis and treatment of renal osteodystrophy focused on changes in bone turnover, current data demonstrate that abnormalities in skeletal mineralization are also prevalent in pediatric chronic kidney disease (CKD) and likely contribute to skeletal morbidities that continue to plague this population. It is now clear that alterations in osteocyte biology, manifested by changes in osteocytic protein expression, occur in early CKD before abnormalities in traditional measures of mineral metabolism are apparent and may contribute to defective skeletal mineralization. Current treatment paradigms advocate the use of 1,25(OH)2vitamin D for the control of secondary hyperparathyroidism; however, these agents fail to correct defective skeletal mineralization and may exacerbate already altered osteocyte biology. Further studies are critically needed to identify the initial trigger for abnormalities of skeletal mineralization as well as the potential effects that current therapeutic options may have on osteocyte biology and bone mineralization.

  2. Role of minerals in animal health disorders

    Directory of Open Access Journals (Sweden)

    Sinovec Zlatan J.

    2005-01-01

    Full Text Available All mineral matter, essential or non-essential, can have a significant influence on production results and the health of animals, if large quantities of them are present in a feed ration. A maximally tolerant content depends on the animal specie and category. Many factors, such as physiological status (growth, lactation, etc., nutritive status, content and ratio of nutritive matter in the ration, duration of exposure, and the biological level of utilization of elements, also affect the maximally tolerant content of mineral matter in feed. The content of certain mineral matter in plant feed significantly depends on the soil factor, as well as the content and level of utilization of mineral matter from the soil. Mn, Se and Mo can be present in plant feed in such quantities as to induce toxicosis. Industrial contaminants, Cd, Pb or F, can contaminate plants, in particular their leaves, in quantities which lead to the appearance of clinical signs of conventional toxicosis. Moreover, natural water can contain large quantities of S, F, Na, Mg, or Fe, and certain mineral matter can get into water through industrial waste. In addition to the above, it is possible to cause unwanted effects through the frequent, but primarily unprofessional use of mineral additives, since it is extremely important, besides meeting the mineral requirements of each individual element, to secure a ratio among the mineral matter themselves as well as with other nutritive matter. Mineral matter present in food are in mutual interference, and these relations can be synergistic or antagonistic. The sufficiency of a large number of mineral matter has a negative effect on the utilization of other matter (conditional and/or border deficiency, while certain elements cause the clinical appearance of toxic effects. The accidental intake of large quantities of certain mineral matter is revealed as clinical signs of acute toxicosis, which is very different from chronic effects caused by

  3. MINER: software for phylogenetic motif identification

    OpenAIRE

    La, David; Livesay, Dennis R.

    2005-01-01

    MINER is web-based software for phylogenetic motif (PM) identification. PMs are sequence regions (fragments) that conserve the overall familial phylogeny. PMs have been shown to correspond to a wide variety of catalytic regions, substrate-binding sites and protein interfaces, making them ideal functional site predictions. The MINER output provides an intuitive interface for interactive PM sequence analysis and structural visualization. The web implementation of MINER is freely available at . ...

  4. Polypeptide Inhibitors of Mineral Scaling and Corrosion

    Science.gov (United States)

    1989-06-01

    peptides are based on natural protein inhibitors of mineral formation and generally are enriched in aspartic acid and phosphoserine. Specifically, the...the protein inhibitors of mineral formation , we evaluated several methods of preparation of phosphopeptides. These included direct polymerization of 2...number of assays have been developed to measure the ability of the peptides to inhibit mineral formation . These include methods for assessing effects on

  5. Mineral distributions at the developing tendon enthesis.

    Directory of Open Access Journals (Sweden)

    Andrea G Schwartz

    Full Text Available Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM. A zone (∼20 µm exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked

  6. Mineral distributions at the developing tendon enthesis.

    Science.gov (United States)

    Schwartz, Andrea G; Pasteris, Jill D; Genin, Guy M; Daulton, Tyrone L; Thomopoulos, Stavros

    2012-01-01

    Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral

  7. Genetic Types of Diamond Mineralization

    Institute of Scientific and Technical Information of China (English)

    A.A.MARAKUSHEV; 桑隆康; 等

    1998-01-01

    The paper describes the proposed models of diamond formation both in meteorites and in kimberlite and lamproite bodies.metamorphic complexes and explosive-ring structures ("astroblemes"),The diamond distribution in meteorites(chondrites,iron meteorites and ureilites)is restricted to taente-kamasite phase.The diamond generation here is tied up with the first stage of evolution of the planets,This stage is characterized by high pressure of hydrogen. leading to the formation of the planet envelope,The second stage of planet evolution began with the progressive imopoverishment of their atmospheres in hydrogen due to its predominant emission into the space and to progressive development of oxidative conditions.The model appears to have proved the relict nature of diamond mineraolization in meteorites.Diamond and other high-pressure minerals(its"satellites") were crystallized without any exception in the early intratelluric stages of peridotite and eclogite-pyroxenite magma evolution just before the magma intrusion into the higher levels of the mantle and crust where diamond is not thermodynamically stable,The ultramafic intrusive bodies(bearing rich relict diamonds)in the dase of a platform paaear to be the substrata for the formation of kimberlite-lamproite magma chambers as a result of magmatic replacement.The model explains the polyfacial nature of diamondiferous eclotgites,pyroxenites and peridotites and discusses the process of inheritance of their diamond mineralization by kimberlites and lamproites.Dimond oproductivity of metamorthic complexes is originated by the inheritance of their diamonds from the above-mentioned primary diamondiferous rocks.Large diamondiferous explosive-ring structures were formed by high-energy endogenic explosion of fluid which came from the Earth's core.This high energy differs endogenic impactogenesis from explosive volcanism.It proceeds at very high temperature to create diaplectic galsses(monomineral pseudomorphs)-the product of

  8. Mineral elements in milk and dairy products

    Directory of Open Access Journals (Sweden)

    Šimun Zamberlin

    2012-06-01

    Full Text Available Mineral elements occur in milk and dairy products as inorganic ions and salts, as well as part of organic molecules, such as proteins, fats, carbohydrates and nucleic acids. The chemical form of mineral elements is important because it determines their absorption in the intestine and their biological utilization. The mineral composition of milk is not constant because it depends on lactation phase, nutritional status of the animal, and environmental and genetic factors. The objective of this research is to point out the research results of chemical form, content and nutritional importance of individual mineral elements that are present in various milks and dairy products.

  9. MINER: software for phylogenetic motif identification.

    Science.gov (United States)

    La, David; Livesay, Dennis R

    2005-07-01

    MINER is web-based software for phylogenetic motif (PM) identification. PMs are sequence regions (fragments) that conserve the overall familial phylogeny. PMs have been shown to correspond to a wide variety of catalytic regions, substrate-binding sites and protein interfaces, making them ideal functional site predictions. The MINER output provides an intuitive interface for interactive PM sequence analysis and structural visualization. The web implementation of MINER is freely available at http://www.pmap.csupomona.edu/MINER/. Source code is available to the academic community on request.

  10. Dietary Supplements and Sports Performance: Minerals

    Directory of Open Access Journals (Sweden)

    Williams Melvin H

    2005-06-01

    Full Text Available Abstract Minerals are essential for a wide variety of metabolic and physiologic processes in the human body. Some of the physiologic roles of minerals important to athletes are their involvement in: muscle contraction, normal hearth rhythm, nerve impulse conduction, oxygen transport, oxidative phosphorylation, enzyme activation, immune functions, antioxidant activity, bone health, and acid-base balance of the blood. The two major classes of minerals are the macrominerals and the trace elements. The scope of this article will focus on the ergogenic theory and the efficacy of such mineral supplementation.

  11. Multiphase Sequestration Geochemistry: Model for Mineral Carbonation

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Hu, Jian Z.; Hoyt, David W.; Felmy, Andrew R.; Rosso, Kevin M.; Wurstner, Signe K.

    2011-04-01

    Carbonation of formation minerals converts low viscosity supercritical CO2 injected into deep saline reservoirs for geologic sequestration into an immobile form. Until recently the scientific focus of mineralization reactions with reservoir rocks has been those that follow an aqueous-mediated dissolution/precipitation mechanism, driven by the sharp reduction in pH that occurs with CO2 partitioning into the aqueous phase. For sedimentary basin formations the kinetics of aqueous-mediated dissolution/precipitation reactions are sufficiently slow to make the role of mineralization trapping insignificant over a century period. For basaltic saline formations aqueous-phase mineralization progresses at a substantially higher rate, making the role of mineralization trapping significant, if not dominant, over a century period. The overlooked mineralization reactions for both sedimentary and basaltic saline formations, however, are those that occur in liquid or supercritical CO2 phase; where, dissolved water appears to play a catalyst role in the formation of carbonate minerals. A model is proposed in this paper that describes mineral carbonation over sequestration reservoir conditions ranging from dissolved CO2 in aqueous brine to dissolved water in supercritical CO2. The model theory is based on a review of recent experiments directed at understanding the role of water in mineral carbonation reactions of interest in geologic sequestration systems occurring under low water contents.

  12. TUCS/phosphate mineralization of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L. [Argonne National Lab., IL (United States)

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  13. Mineral Facilities of Latin America and Canada

    Science.gov (United States)

    Bernstein, Rachel; Eros, Mike; Quintana-Velazquez, Meliany

    2006-01-01

    This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. Records include attributes such as commodity, country, location, company name, facility type and capacity if applicable, and generalized coordinates. The data were compiled from multiple sources, including the 2003 and 2004 USGS Minerals Yearbooks (Latin America and Candada volume), data to be published in the 2005 Minerals Yearbook Latin America and Canada Volume, minerals statistics and information from the USGS minerals information Web site (minerals.usgs.gov/minerals), and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies,and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists.

  14. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091570 Ge Yunjin(College of Geo-Resource and Information,China University of Petroleum,Dongying 257061,China);Chen Yong Advance in Low Temperature Phase Transition and Raman Spectrum Technique in Composition Determination of Fluid Inclusions(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,27(3),2008,p.207-210,22 refs.)Key words:fluid inclusions,Raman spectraThe principle and development of low-temperature analytical techniques for fluid inclusions were expounded.The traditional low-temperature analytical technology mainly focused on the measurement of inorganic salt using congealed microthermometry,but now it is developed to semi-quantitative and quantitative analysis of fluid inclusions using in-situ cryogenic Raman spectrometry.

  15. Leptin and bone mineral density

    DEFF Research Database (Denmark)

    Morberg, Cathrine M.; Tetens, Inge; Black, Eva

    2003-01-01

    Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg....../m(2), age 47.5 +/- 5.1 yr). Whole-body dual-energy x-ray absorptiometry scan measured BMD, fat mass, and lean mass. Fasting serum leptin (nanograms per milliliter) was strongly associated with fat mass (kilograms) in both controls (r = 0.876; P ....001). An inverse relation between BMD adjusted for body weight and serum leptin emerged in both the control group (r = -0.186; P

  16. Geology, geochemistry, geophysics, mineral occurrences, and mineral resource assessment for the commonwealth of Puerto Rico

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geologic map with faults, along with additional scientific information needed for mineral resource assessment (geochemical analyses, mineral occurrences, geologic...

  17. Aggregate and Mineral Resources, This data set consists of mineral deposit areas (KMDAs) for locatable minerals., Published in 1993, Arizona State Land Department.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Aggregate and Mineral Resources dataset as of 1993. It is described as 'This data set consists of mineral deposit areas (KMDAs) for locatable minerals.'. Data...

  18. The nanophase iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism

  19. U.S. Geological Survey Minerals Yearbook—Metals and Minerals

    Science.gov (United States)

    ,

    2016-01-01

    This edition of the U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries during 2012 and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:• Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.• Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.• Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

  20. European mineral statistics 2009-13 : a product of the World Mineral Statistics database

    OpenAIRE

    Brown, T. J.; Hobbs, S.F.; Mills, A. J.; Idoine, N.E.; Wrighton, C.E.

    2015-01-01

    This volume is the latest edition of a series that began in 2002 following the replacement of ‘World Mineral Statistics’ with ‘World Mineral Production’. It contains mineral production, import and export data for more than 70 mineral commodities, for 36 European countries including all EU Member States and EU Candidate Countries, plus Norway and Switzerland. These data are presented in two sections: by individual country and by commodity; the latter is illustrated by graphics. It remains the ...

  1. European Mineral Statistics 2010-14: a product of the World Mineral statistics database

    OpenAIRE

    Brown, T. J.; Hobbs, S.F.; Idoine, N.E.; Mills, A. J.; Wrighton, C.E.; Raycraft, E.R.

    2016-01-01

    European Mineral Statistics provides statistical information about minerals and metals in Europe. It provides the essential background intelligence for any European minerals-related activities. Production, export and import tables are presented for all EU members and EU candidate countries, plus Norway and Switzerland, in two sections: •by individual country •by commodity, with bullets on salient features and graphics More than 70 different mineral commodities are included from ...

  2. Different supplementation of minerals in bats and the consequences on bone mineral density

    OpenAIRE

    2006-01-01

    We investigated the consequences of mineral supplementation of mealworms at a facility where mustached bats (Pteronotus parnellii rubiginosus) from Trinidad were kept for experimental purposes. For 11 months after capture from the wild, the animals were constantly housed indoors and fed a diet of mealworms without mineral supplementation. After several animals died with skulls soft at palpation, this diet was suspected to be mineral deficient. From then on, mealworms were placed on a mineral ...

  3. EXTRATERRESTRIAL MINERALS AND FUTURE FRONTIERS IN MINERAL EXPLORATION

    Directory of Open Access Journals (Sweden)

    WILMER GIRALDO

    2013-01-01

    Full Text Available Debido a las altas tasas de consumo de minerales y el alto crecimiento de la población humana, los recursos minerales en el planeta Tierra se encuentran en proceso de agotamiento, esta escasez crea la necesidad de encontrar nuevas alternativas para suplir las crecientes necesidades. Una alternativa adicional a la tradicional búsqueda de nuevos yacimientos en la tierra, es la búsqueda de yacimientos más allá de nuestro planeta, estos nuevos recursos se pueden buscar en la vecindad de nuestro planeta. La extracción en cuerpos de nuestro sistema solar como la Luna, Marte y el cinturón de asteroides puede proporcionar abundantes recursos energéticos como el helio 3 y minerales como el potasio, elementos de tierras raras, hierro y minerales del grupo del platino. Ahora, algunas compañías están planeando esta exploración y para los geólogos y profesionales de la minería en general, esto abre grandes posibilidades para la investigación científica, innovación tecnológica y desarrollo profesional en nuevos campos.

  4. Mineral Resource Team 2010 Activities Summary

    Science.gov (United States)

    2011-01-29

    of the Himalayas where the Indian subcontinent collided with Eurasia, the country’s unique geological foundation created thousands of mineral...on or below the paleo -ocean floor. Some VMS deposits are distinctive in that Cu ores formed by hydrothermal circulation and exhalation of minerals

  5. Minerals in fish: does the source matter?

    NARCIS (Netherlands)

    Antony Jesu Prabhu, P.

    2015-01-01

    Antony Jesu Prabhu, P. (2015). Minerals in fish: does the source matter? PhD thesis. Wageningen University, The Netherlands. Minerals are a group of micro-nutrients essential to fish. Meta-analysis of literature data was performed to identify the appropriate response criterion to de

  6. Mineral nutrition of cocoa : a review

    NARCIS (Netherlands)

    Vliet, van J.A.; Slingerland, M.A.; Giller, K.E.

    2015-01-01

    This literature review on mineral nutrition of cocoa was commissioned by the Scientific Committee of the Cocoa Fertiliser Initiative to address the following questions: What knowledge is currently available about mineral nutrition of cocoa? What are the current knowledge gaps? What are the key areas

  7. Technology sandwich panels with mineral wool insulation

    OpenAIRE

    Tyulenev M.; Burtzeva M.; Mednikova E.

    2016-01-01

    Sandwich panel — self–supporting structure consisting of metal cladding and thermal insulation core. As a heat–insulating core used mineral wool, foamed plastics. Production of sandwich panels with insulation mineral wool performed on modular lines for the production of aggregate or conveyer scheme. Sandwich panels are used as load–bearing elements of the facades, as well as a roof covering.

  8. CAS researchers find a new mineral

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Mineralogists from the CAS Guangzhou Institute of Geochemistry (GIG) recently discovered Xieite, a chromium-iron oxide in its natural state. It has been authorized as a new mineral by Commission on New Minerals Nomenclature and Classification under the International Mineralogical Association (CNMNC-IMA).

  9. Dehydration-induced luminescence in clay minerals

    Science.gov (United States)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  10. Utilization of mining and mineral wastes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Ho; Hong, Seung Woong; Choi, Young Yoon; Kim, Byung Gyu; Park, Je Shin [Korea Institute of Geology Mining and Materials, Taejon (Korea)

    1998-12-01

    Up to now, it is estimated that more than 50 million tons of mineral wastes have been generated mining industries and deposited on the land in Korea. Much of cultivated land and hilly areas have been occupied by this wastes, which cause pollution of the environment. Utilization of the mineral wastes is preferable to stabilization because full use would both eliminate the waste and broaden the mineral resource base. Therefore, the development of utilization techniques of mineral wastes is very important not only for improving the environment but also for resource conservation. In countries with high population and poor natural resources like Korea, the utilization of these wastes is essential to decrease the environmental problem and the secure the resources and the study on this field play a important part. Therefore, the objective of this study is to develop the utilization techniques of the mineral wastes. In first year's research, the contents and scope of this study are 1) Present condition and Field Survey on the mineral wastes with respect of their utilization, 2) Reviews of Current effects and research to utilize mineral wastes, 3) Characterization of mineral wastes and environmental test, 4) Evaluation and study on the utilization. (author). 67 refs., 25 tabs., 54 figs.

  11. Mineral Oil Aspiration Related Juvenile Idiopathic Arthritis

    OpenAIRE

    Nelson, Andrew D.; Fischer, Philip R.; Reed, Ann M.; Wylam, Mark E.

    2015-01-01

    We describe the development of rheumatoid factor-positive migratory polyarthritis in a 5-year-old male who had been administered bidaily oral mineral oil as a laxative since birth. Minor respiratory symptoms, radiographic and bronchoscopic findings were consistent with chronic lipoid pneumonia. We speculate that immune sensitization to mineral oil promoted the clinical syndrome of juvenile idiopathic arthritis.

  12. Acidosis inhibits mineralization in human osteoblasts.

    Science.gov (United States)

    Takeuchi, Shoko; Hirukawa, Koji; Togari, Akifumi

    2013-09-01

    Osteoblasts and osteoclasts maintain bone volume. Acidosis affects the function of these cells including mineral metabolism. We examined the effect of acidosis on the expression of transcription factors and mineralization in human osteoblasts in vitro. Human osteoblasts (SaM-1 cells) derived from the ulnar periosteum were cultured with α-MEM containing 50 μg/ml ascorbic acid and 5 mM β-glycerophosphate (calcifying medium). Acidosis was induced by incubating the SaM-1 cells in 10 % CO₂ (pH approximately 7.0). Mineralization, which was augmented by the calcifying medium, was completely inhibited by acidosis. Acidosis depressed c-Jun mRNA and increased osteoprotegerin (OPG) production in a time-dependent manner. Depressing c-Jun mRNA expression using siRNA increased OPG production and inhibited mineralization. In addition, depressing OPG mRNA expression with siRNA enhanced mineralization in a dose-dependent manner. Acidosis or the OPG protein strongly inhibited mineralization in osteoblasts from neonatal mice. The present study was the first to demonstrate that acidosis inhibited mineralization, depressed c-Jun mRNA expression, and induced OPG production in human osteoblasts. These results suggest that OPG is involved in mineralization via c-Jun in human osteoblasts.

  13. ASEAN Mineral Database and Information System (AMDIS)

    Science.gov (United States)

    Okubo, Y.; Ohno, T.; Bandibas, J. C.; Wakita, K.; Oki, Y.; Takahashi, Y.

    2014-12-01

    AMDIS has lunched officially since the Fourth ASEAN Ministerial Meeting on Minerals on 28 November 2013. In cooperation with Geological Survey of Japan, the web-based GIS was developed using Free and Open Source Software (FOSS) and the Open Geospatial Consortium (OGC) standards. The system is composed of the local databases and the centralized GIS. The local databases created and updated using the centralized GIS are accessible from the portal site. The system introduces distinct advantages over traditional GIS. Those are a global reach, a large number of users, better cross-platform capability, charge free for users, charge free for provider, easy to use, and unified updates. Raising transparency of mineral information to mining companies and to the public, AMDIS shows that mineral resources are abundant throughout the ASEAN region; however, there are many datum vacancies. We understand that such problems occur because of insufficient governance of mineral resources. Mineral governance we refer to is a concept that enforces and maximizes the capacity and systems of government institutions that manages minerals sector. The elements of mineral governance include a) strengthening of information infrastructure facility, b) technological and legal capacities of state-owned mining companies to fully-engage with mining sponsors, c) government-led management of mining projects by supporting the project implementation units, d) government capacity in mineral management such as the control and monitoring of mining operations, and e) facilitation of regional and local development plans and its implementation with the private sector.

  14. Mineral resources and geo-engineering

    Directory of Open Access Journals (Sweden)

    Fathi Habashi

    2015-12-01

    Full Text Available Metals used in everyday life are produced from ores occurring in the Earth’s crust. Geological processes are known to concentrate minerals to form ores of economic value. Mineral processing engineers concentrate these ores by mechanical and physico-chemical methods while the extractive metallurgist extracts the metals by chemical means.

  15. Earth mineral resource of the month: asbestos

    Science.gov (United States)

    Virta, Robert L.

    2010-01-01

    The article discusses the characteristics and feature of asbestos. According to the author, asbestos is a generic name for six needle-shaped minerals that possess high tensile strengths, flexibility, and resistance to chemical and thermal degradation. These minerals are actinolite, amosite, anthophyllite, chrysolite, crocilodite and tremolite. Asbestos is used for strengthening concrete pipe, plastic components, and gypsum plasters.

  16. Control of Vertebrate Skeletal Mineralization by Polyphosphates

    Science.gov (United States)

    Omelon, Sidney; Georgiou, John; Henneman, Zachary J.; Wise, Lisa M.; Sukhu, Balram; Hunt, Tanya; Wynnyckyj, Chrystia; Holmyard, Douglas; Bielecki, Ryszard; Grynpas, Marc D.

    2009-01-01

    Background Skeletons are formed in a wide variety of shapes, sizes, and compositions of organic and mineral components. Many invertebrate skeletons are constructed from carbonate or silicate minerals, whereas vertebrate skeletons are instead composed of a calcium phosphate mineral known as apatite. No one yet knows why the dynamic vertebrate skeleton, which is continually rebuilt, repaired, and resorbed during growth and normal remodeling, is composed of apatite. Nor is the control of bone and calcifying cartilage mineralization well understood, though it is thought to be associated with phosphate-cleaving proteins. Researchers have assumed that skeletal mineralization is also associated with non-crystalline, calcium- and phosphate-containing electron-dense granules that have been detected in vertebrate skeletal tissue prepared under non-aqueous conditions. Again, however, the role of these granules remains poorly understood. Here, we review bone and growth plate mineralization before showing that polymers of phosphate ions (polyphosphates: (PO3−)n) are co-located with mineralizing cartilage and resorbing bone. We propose that the electron-dense granules contain polyphosphates, and explain how these polyphosphates may play an important role in apatite biomineralization. Principal Findings/Methodology The enzymatic formation (condensation) and destruction (hydrolytic degradation) of polyphosphates offers a simple mechanism for enzymatic control of phosphate accumulation and the relative saturation of apatite. Under circumstances in which apatite mineral formation is undesirable, such as within cartilage tissue or during bone resorption, the production of polyphosphates reduces the free orthophosphate (PO43−) concentration while permitting the accumulation of a high total PO43− concentration. Sequestering calcium into amorphous calcium polyphosphate complexes can reduce the concentration of free calcium. The resulting reduction of both free PO43− and free

  17. Biohydrometallurgy for nonsulfidic minerals - A review

    Energy Technology Data Exchange (ETDEWEB)

    Jain, N.; Sharma, D.K. [Indian Institute of Technology of Delhi, New Delhi (India). Center for Energy Studies

    2004-05-01

    Bioleaching is a technology applicable to metal extraction from low-grade ores, ore beneficiation, coal beneficiation, metal detoxification, and recovery of metals from waste materials. The technology is environmentally sound and it may lower operational cost and energy requirement. Whereas leaching of sulfidic minerals using chemolithoautotrophic bacteria is the most studied and commercially exploitable aspect of mineral biotechnology today, there is a dearth of literature on the dissolution of nonsulfidic minerals. Biohydrometallurgy of nonsulfidic minerals involves the action of heterotrophic microorganisms. Heterotrophic bacteria and fungi have the potential for producing acidic metabolites that are able to solubilize oxide, silicate, carbonate and hydroxide minerals by reduction, acidolysis and complexation mechanisms. It is an important aspect of biohydrometallugy that requires development to meet future needs.

  18. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    Sanjay Upadhyay; Hem Chandra; Meenakashi Joshi; Deepika P Joshi

    2011-01-01

    The knowledge of elasticity of the minerals is useful for interpreting the structure and composition of the lower mantle and also in seismic studies. The purpose of the present study is to discuss a simple and straightforward method for evaluating thermoelastic properties of minerals at high temperatures. We have extended the Kumar’s formulation by taking into the account the concept of anharmonicity in minerals above the Debye temperature (D). In our present study, we have investigated the thermophysical properties of two minerals (pyrope-rich garnet and MgAl2O4) under high temperatures and calculated the second-order elastic constant () and bulk modulus (T) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (T) as temperature-independent and then by treating T as temperature-dependent parameter. The results obtained when T is temperature-dependent are in close agreement with experimental data.

  19. Raising environmental awareness among miners in Iran

    Directory of Open Access Journals (Sweden)

    Ezatollah Mozaffari

    2013-06-01

    Full Text Available Generation of waste is inevitable but controllable in minerals industry. The aim of this research is to find ways forraising environmental awareness among miners. Miners’ attitude towards environmental mining has been investigated. A survey has been done collecting mine managers’ point of view coupled with current trend on mine waste management in Iran. Their opinions on methods used for minerals extraction and waste productionare sought in order to investigate possible educational schemes for waste reduction and mine waste disposal. The type and quantity of waste produced by respondents have been identified to prioritise the wastes produced in minesites. Environmental legislations and policies for good practice minerals extraction are surveyed anddemonstrated. These are regarded as our clients’ preferences on managing mining waste. When combined with other existing policies and methods, they could become part of a learning program to boost awareness among miners.

  20. 冷却方式对硫系玻璃性能的影响%Influence of cooling methods on the properties of chalcogenide glass

    Institute of Scientific and Technical Information of China (English)

    常芳娥; 朱仲飞; 许军锋; 朱满; 坚增运

    2015-01-01

    T he effect of cooling methods on the microstructure ,thermal stability ,optical and mechanical proper‐ties of 99 7.5Ge23 Se67 Sb10‐0 2.5RbI glass were studied by DSC ,XRD ,SEM ,FT‐IR and Vickers hardness test in this study .The results indicated that ,for air cooled glass ,the infrared transmittance at wavelength of 8‐12 μm was above 70% ,which was higher than that of water cooled glass (64% ) .However ,due to the slow cooling rate of air cooled ,the solid solubility of hydrogen in selenium increases ,thus the absorption of impurities was also stronger than that of water cooled glass .For the thermal‐treatment samples ,the diffraction peaks of Sb2 Se3 and GeSe2 crystals can be found at 280 ℃/20 h for the glass cooled by air ,but at 300 ℃/20 h for the glass cooled by water .After thermal treat‐ment ,the fracture toughness of water cooled glass can reach to 0 4.14 MPa・m1/2 ,increased 26% compared with that without thermal treatment ,and it was higher than the maximum KIC (0 3.68 MPa・m1/2 ) of air cooled glass .Conse‐quently ,water cooled chalcogenide glass has a higher stability and a better fracture toughness ,thus it was more suitable for preparing micro‐crystallizing chalcogenide glass .%通过DSC、XRD、SEM、FT‐IR和显微硬度测试等分析手段,研究了冷却方式对99.75Ge23 Se67 Sb10‐02.5RbI玻璃组织、热稳定性以及光学和力学等性能的影响。结果表明,采用空冷制得的试样在8~12μm 波段红外透过率达70%以上,高于水冷试样(64%),但由于空冷冷速慢,氢在硒中的固溶度大,导致杂质吸收也大于水冷试样;空冷试样在280℃热处理20 h可从XRD检测发现明显Sb2 Se3和GeSe2的结晶峰,而水冷试样在300℃热处理20 h后才能检测到结晶峰;经过热处理,水冷试样的最大 K IC值可达到04.14 M Pa・m1/2,较未热处理值提高了26%,且高于空冷试样的最大 K IC (0.368 M Pa・ m1/2),因