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Sample records for la-doped mg2si sn

  1. Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

    KAUST Repository

    Zhang, Bo

    2017-05-22

    Thin-film Mg2Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed that the deposited films are polycrystalline Mg2Si. The Sn and Al doping concentrations were measured using Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray spectroscopy (EDS). The charge carrier concentration and the charge carrier type of the Mg2Si films were measured using a Hall bar structure. Hall measurements show that as the doping concentration increases, the carrier concentration of the Al-doped films increases, whereas the carrier concentration of the Sn-doped films decreases. Combined with the resistivity measurements, the mobility of the Al-doped Mg2Si films is found to decrease with increasing doping concentration, whereas the mobility of the Sn-doped Mg2Si films is found to increase.

  2. Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

    KAUST Repository

    Zhang, Bo; Zheng, Tao; Sun, Ce; Guo, Zaibing; Kim, Moon J.; Alshareef, Husam N.; Quevedo-Lopez, Manuel; Gnade, Bruce E.

    2017-01-01

    Thin-film Mg2Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed

  3. Relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn: Consistent parameterization and prediction of Seebeck coefficients

    Science.gov (United States)

    Shi, Guangsha; Kioupakis, Emmanouil

    2018-02-01

    We apply density functional and many-body perturbation theory calculations to consistently determine and parameterize the relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn, and predict the Seebeck coefficient as a function of doping and temperature. The quasiparticle band gaps, including spin-orbit coupling effects, are determined to be 0.728 eV, 0.555 eV, and 0.142 eV for Mg2Si, Mg2Ge, and Mg2Sn, respectively. The inclusion of the semicore electrons of Mg, Ge, and Sn in the valence is found to be important for the accurate determination of the band gaps of Mg2Ge and Mg2Sn. We also developed a Luttinger-Kohn Hamiltonian and determined a set of band parameters to model the near-edge relativistic quasiparticle band structure consistently for all three compounds that can be applied for thermoelectric device simulations. Our calculated values for the Seebeck coefficient of all three compounds are in good agreement with the available experimental data for a broad range of temperatures and carrier concentrations. Our results indicate that quasiparticle corrections are necessary for the accurate determination of Seebeck coefficients at high temperatures at which bipolar transport becomes important.

  4. THERMOELECTRIC PROPERTIES OF HOT-PRESSED p-TYPE Mg2Si0.3Sn0.7 SOLID SOLUTION

    Directory of Open Access Journals (Sweden)

    G. N. Isachenko

    2014-05-01

    Full Text Available It is shown that thermoelectric energy conversion which gives the possibility for utilizing a low potential heat is one of the ways for adoption of energy-saving technologies; and semiconductor materials with p-type and n-type conductivities having high thermoelectric figure of merit are necessary for operation of thermoelectric generators. The paper deals with possibility of usage of the p-Mg2Si0.3Sn0.7 solid solution (with a nanostructured modification as a couple for the well studied thermoelectric material based on n-Mg2Si-Mg2Sn. A technological scheme for fabrication of heavily doped Mg2Si0.3Sn0.7 solid solution of p-type by hot pressing from nanopowder is developed. The given technology has made it possible to reduce duration of a homogeneous material fabrication and has improved its physical and chemical properties. The samples were made by three ways: direct fusion for polycrystals fabrication; hot pressing from microparticles; nanostructuring, i.e. hot pressing from nanoparticles. By X-ray diffraction it is shown that sizes of structural elements in the fabricated samples are about 40 nm. The probe technique is used for measurement of electric conductivity and Seebeck coefficient. The stationary absolute method is used for measurement of thermal conductivity. Thermoelectric figure of merit is defined by measured values of kinetic coefficients in the temperatures range of 77 – 800 K. It was demonstrated, that electric conductivity, Seebeck coefficient and the power factor do not depend practically on a way of solid solution preparation. Thermal conductivity of samples pressed from nanoparticles has appeared to be higher, than of samples, obtained by direct fusion; i.e. in this case nanostructuring has not led to increase of thermoelectric figure of merit. The conclusion is drawn, that polycrystalline semiconductor Mg2Si0.3Sn0.7 can be used as a p-branch for a thermoelectric generator though nanostructuring has not led to the figure of

  5. High figure of merit and thermoelectric properties of Bi-doped Mg2Si0.4Sn0.6 solid solutions

    International Nuclear Information System (INIS)

    Liu, Wei; Zhang, Qiang; Yin, Kang; Chi, Hang; Zhou, Xiaoyuan; Tang, Xinfeng; Uher, Ctirad

    2013-01-01

    The study of Mg 2 Si 1−x Sn x -based thermoelectric materials has received widespread attention due to a potentially high thermoelectric performance, abundant raw materials, relatively low cost of modules, and non-toxic character of compounds. In this research, Mg 2.16 (Si 0.4 Sn 0.6 ) 1−y Bi y solid solutions with the nominal Bi content of 0≤y≤0.03 are prepared using a two-step solid state reaction followed by spark plasma sintering consolidation. Within this range of Bi concentrations, no evidence of second phase segregation was found. Bi is confirmed to occupy the Si/Sn sites in the crystal lattice and behaves as an efficient n-type dopant in Mg 2 Si 0.4 Sn 0.6 . Similar to the effect of Sb, Bi doping greatly increases the electron density and the power factor, and reduces the lattice thermal conductivity of Mg 2.16 Si 0.4 Sn 0.6 solid solutions. Overall, the thermoelectric figure of merit of Bi-doped Mg 2.16 Si 0.4 Sn 0.6 solid solutions is improved by about 10% in comparison to values obtained with Sb-doped materials of comparable dopant content. This improvement comes chiefly from a marginally higher Seebeck coefficient of Bi-doped solid solutions. The highest ZT∼1.4 is achieved for the y=0.03 composition at 800 K. - Graphical abstract: (a)The relationship between electrical conductivity and power factor for Sb/Bi-doped Mg 2.16 (Si 0.4 Sn 0.6 ) 1−y (Sb/Bi) y (0 2.16 (Si 0.4 Sn 0.6 ) 1−y Bi y (0≤y≤0.03) solid solutions. (c)Temperature dependent dimensionless figure of merit ZT of Mg 2.16 (Si 0.4 Sn 0.6 ) 1−y Bi y (0≤y≤0.03) solid solutions. - Highlights: • Bi doped Mg 2.16 Si 0.4 Sn 0.6 showed 15% enhancement in the power factor as compared to Sb doped samples. • Bi doping reduced κ ph of Mg 2.16 Si 0.4 Sn 0.6 due to stronger point defect scattering. • The highest ZT=1.4 at 800 K was achieved for Mg 2.16 (Si 0.4 Sn 0.6 ) 0.97 Bi 0.03

  6. Variation of equation of state parameters in the Mg2(Si 1-xSnx) alloys

    KAUST Repository

    Pulikkotil, Jiji Thomas Joseph

    2010-08-03

    Thermoelectric performance peaks up for intermediate Mg2(Si 1-x:Snx) alloys, but not for isomorphic and isoelectronic Mg2(Si1-xGex) alloys. A comparative study of the equation of state parameters is performed using density functional theory, Green\\'s function technique, and the coherent potential approximation. Anomalous variation of the bulk modulus is found in Mg2(Si1-xSn x) but not in the Mg2(Si1-xGex) analogs. Assuming a Debye model, linear variations of the unit cell volume and pressure derivative of the bulk modulus suggest that lattice effects are important for the thermoelectric response. From the electronic structure perspective, Mg2(Si1-xSnx) is distinguished by a strong renormalization of the anion-anion hybridization. © 2010 IOP Publishing Ltd.

  7. High-temperature thermoelectric properties of La-doped BaSnO3 ceramics

    International Nuclear Information System (INIS)

    Yasukawa, Masahiro; Kono, Toshio; Ueda, Kazushige; Yanagi, Hiroshi; Hosono, Hideo

    2010-01-01

    To elucidate the thermoelectric properties at high temperatures, perovskite-type La-doped BaSnO 3 ceramics were fabricated by a polymerized complex (PC) method and subsequent spark plasma sintering (SPS) technique. Fine powders of Ba 1-x La x SnO 3 (x = 0.00-0.07) were prepared by the PC method using citrate complexes, and SPS treatment converted the powders into dense ceramics with relative densities of 93-97%. The La content dependence of the lattice parameter suggested that the solubility of La for Ba sites was approximately x = 0.03. The temperature dependence of the electrical conductivity σ and Seebeck coefficient S showed that each La-doped ceramic was an n-type degenerate semiconductor in the measured temperature range of 373-1073 K. The La content dependence of the S values indicated that the electron carrier concentration increased successively up to x = 0.03, which was the solubility limit of the La atoms. The thermoelectric power factors S 2 σ increased drastically with La doping, and reached a maximum for x = 0.01 with values of 0.8 x 10 -4 W m -1 K -2 at 373 K to 2.8 x 10 -4 W m -1 K -2 at 1073 K.

  8. Photoluminescence of Mg_2Si films fabricated by magnetron sputtering

    International Nuclear Information System (INIS)

    Liao, Yang-Fang; Xie, Quan; Xiao, Qing-Quan; Chen, Qian; Fan, Meng-Hui; Xie, Jing; Huang, Jin; Zhang, Jin-Min; Ma, Rui; Wang, Shan-Lan; Wu, Hong-Xian; Fang, Di

    2017-01-01

    Highlights: • High quality Mg_2Si films were grown on Si (111) and glass substrates with magnetron sputtering, respectively. • The first observation of Photoluminescence (PL) of Mg_2Si films was reported. • The Mg_2Si PL emission wavelengths are almost independence on temperature in the range of 77–300 K. • The strongest PL emissions may be attributed to interstitial Mg donor level to valence band transitions. • The activation energy of Mg_2Si is determined from the quenching of major luminescence peaks. - Abstract: To understand the photoluminescence mechanisms and optimize the design of Mg_2Si-based light-emitting devices, Mg_2Si films were fabricated on silicon (111) and glass substrates by magnetron sputtering technique, and the influences of different substrates on the photoelectric properties of Mg_2Si films were investigated systematically. The crystal structure, cross-sectional morphology, composition ratios and temperature-dependent photoluminescence (PL) of the Mg_2Si films were examined using X-ray diffraction (XRD), Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and PL measurement system, respectively. XRD results indicate that the Mg_2Si film on Si (111) displays polycrystalline structure, whereas Mg_2Si film on glass substrate is of like-monocrystalline structure.SEM results show that Mg_2Si film on glass substrate is very compact with a typical dense columnar structure, and the film on Si substrate represents slight delamination phenomenon. EDS results suggest that the stoichiometry of Mg and Si is approximately 2:1. Photoluminescence (PL) of Mg_2Si films was observed for the first time. The PL emission wavelengths of Mg_2Si are almost independence on temperature in the range of 77–300 K. The PL intensity decreases gradually with increasing temperature. The PL intensity of Mg_2Si films on glass substrate is much larger than that of Mg_2Si film on Si (111) substrate. The activation energy of 18 meV is

  9. Conduction band edge effective mass of La-doped BaSnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    James Allen, S., E-mail: allen@itst.ucsb.edu; Law, Ka-Ming [Physics Department, University of California, Santa Barbara, California 93106-5100 (United States); Raghavan, Santosh; Schumann, Timo; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

    2016-06-20

    BaSnO{sub 3} has attracted attention as a promising material for applications requiring wide band gap, high electron mobility semiconductors, and moreover possesses the same perovskite crystal structure as many functional oxides. A key parameter for these applications and for the interpretation of its properties is the conduction band effective mass. We measure the plasma frequency of La-doped BaSnO{sub 3} thin films by glancing incidence, parallel-polarized resonant reflectivity. Using the known optical dielectric constant and measured electron density, the resonant frequency determines the band edge electron mass to be 0.19 ± 0.01. The results allow for testing band structure calculations and transport models.

  10. Luminescence characteristics of Mg2SiO4:Nd

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  11. Adsorption-controlled growth of La-doped BaSnO3 by molecular-beam epitaxy

    Directory of Open Access Journals (Sweden)

    Hanjong Paik

    2017-11-01

    Full Text Available Epitaxial La-doped BaSnO3 films were grown in an adsorption-controlled regime by molecular-beam epitaxy, where the excess volatile SnOx desorbs from the film surface. A film grown on a (001 DyScO3 substrate exhibited a mobility of 183 cm2 V−1 s−1 at room temperature and 400 cm2 V−1 s−1 at 10 K despite the high concentration (1.2 × 1011 cm−2 of threading dislocations present. In comparison to other reports, we observe a much lower concentration of (BaO2 Ruddlesden-Popper crystallographic shear faults. This suggests that in addition to threading dislocations, other defects—possibly (BaO2 crystallographic shear defects or point defects—significantly reduce the electron mobility.

  12. Microstructural Analysis of AM50/Mg2Si Cast Magnesium Composites

    Directory of Open Access Journals (Sweden)

    Malik M.A.

    2012-12-01

    Full Text Available AM50/Mg2Si composites containing 5.7 wt. % and 9.9 wt. %. of Mg2Si reinforcing phase were prepared successfully by casting method. The microstructure of the cast AM50/Mg2Si magnesium matrix composites was investigated by light microscopy and X-ray diffractometry (XRD. The microstructure of these composites was characterized by the presence of α-phase (a solid solution of aluminium in magnesium, Mg17Al12 (γ-phase, Al8Mn5 and Mg2Si. It was demonstrated that the Mg2Si phase was formed mainly as primary dendrites and eutectic.

  13. Refinement of Mg2Si reinforcement in a commercial Al–20%Mg2Si in-situ composite with bismuth, antimony and strontium

    International Nuclear Information System (INIS)

    Nordin, Nur Azmah; Farahany, Saeed; Ourdjini, Ali; Abu Bakar, Tuty Asma; Hamzah, Esah

    2013-01-01

    Refinement by addition elements of Al–Mg 2 Si alloys is known to result in a change of primary Mg 2 Si morphology. In this paper, the effects of Bi, Sb and Sr on the characteristic parameters of Al–20%Mg 2 Si in-situ composite have been investigated by computer aided cooling curve thermal analysis and microstructural inspection. Size, density and aspect ratio measurements showed that additions of 0.4 wt.% Bi, 0.8 wt.% Sb and 0.01 wt.% Sr refined the Mg 2 Si reinforcement. Exceeding these concentrations, however, resulted in coarsening of Mg 2 Si particles with no change in the morphology. The results also showed that addition elements caused a decrease in the nucleation and growth temperatures of Mg 2 Si particles. The refining effect of Bi, Sb and Sr is likely to be related to the effect of oxide bifilms suspended in the composite melt as favored nucleation substrates for Mg 2 Si particles. - Highlight: • 0.4 wt.%, 0.8 wt.% and 0.01 wt.% is the optimum content for Bi, Sb and Sr addition. • Exceeding optimum concentration resulted in the coarsening of reinforcements. • Nucleation and growth temperatures decrease with addition of Bi, Sb and Sr. • The refining effect of Bi, Sb and Sr is likely to be related to the oxide bifilms

  14. Variation of equation of state parameters in the Mg2(Si 1-xSnx) alloys

    KAUST Repository

    Pulikkotil, Jiji Thomas Joseph; Alshareef, Husam N.; Schwingenschlö gl, Udo

    2010-01-01

    Thermoelectric performance peaks up for intermediate Mg2(Si 1-x:Snx) alloys, but not for isomorphic and isoelectronic Mg2(Si1-xGex) alloys. A comparative study of the equation of state parameters is performed using density functional theory, Green

  15. Effect of Ni on eutectic structural evolution in hypereutectic Al-Mg2Si cast alloys

    International Nuclear Information System (INIS)

    Li Chong; Wu Yaping; Li Hui; Wu Yuying; Liu Xiangfa

    2010-01-01

    Research highlights: → By the injection of rod-like NiAl 3 phase in Al-Mg 2 Si alloys, Al-Mg 2 Si binary eutectic structure gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic. → The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. → The mechanism of structural evolution was analyzed in terms of the detailed microstructural observations. → The high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structural evolution. - Abstract: The aim of this work is to investigate the eutectic structural evolution of hypereutectic Al-20% Mg 2 Si with Ni addition under a gravity casting process. Three-dimensional morphologies of eutectic phases were observed in detail using field emission scanning electron microscopy, after Al matrix was removed by deep etching or extraction. The results show that Al-Mg 2 Si binary eutectic gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic with the increase of Ni content, and flake-like eutectic Mg 2 Si transforms into rods. The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. Further, the high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structure evolution, and the mechanism of structural evolution was discussed and analyzed in terms of the detailed microstructural observations.

  16. Polarized micro-Raman scattering characterization of Mg2Si nanolayers in (001) Si matrix

    International Nuclear Information System (INIS)

    Zlateva, G; Atanassov, A; Baleva, M; Nikolova, L; Abrashev, M V

    2007-01-01

    An orientational growth of the Mg 2 Si lattice relative to the Si lattice is considered assuming minimum mismatch of their lattice parameters. The Raman scattering cross-sections are calculated for the four possible orientations of the Mg 2 Si lattice positioned in this way. The integral intensity ratios for the F 2g mode of Mg 2 Si in different polarization configurations, obtained from the experimental spectra, are compared with the calculated ratios. It is found that the Mg 2 Si nanolayer's morphology is sensitive to the implantation energy, which determines both the peak Mg concentration in the initial implantation profile and its position in the sample depth. At a peak concentration of the order of the stoichiometric concentration, the layers are highly oriented. When the peak concentration is higher and the peak is placed closer to the surface, the layers are polycrystalline

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  18. Significant enhancement of thermoelectric properties and metallization of Al-doped Mg2Si under pressure

    International Nuclear Information System (INIS)

    Morozova, Natalia V.; Korobeinikov, Igor V.; Karkin, Alexander E.; Shchennikov, Vladimir V.; Ovsyannikov, Sergey V.; Takarabe, Ken-ichi; Mori, Yoshihisa; Nakamura, Shigeyuki

    2014-01-01

    We report results of investigations of electronic transport properties and lattice dynamics of Al-doped magnesium silicide (Mg 2 Si) thermoelectrics at ambient and high pressures to and beyond 15 GPa. High-quality samples of Mg 2 Si doped with 1 at. % of Al were prepared by spark plasma sintering technique. The samples were extensively examined at ambient pressure conditions by X-ray diffraction studies, Raman spectroscopy, electrical resistivity, magnetoresistance, Hall effect, thermoelectric power (Seebeck effect), and thermal conductivity. A Kondo-like feature in the electrical resistivity curves at low temperatures indicates a possible magnetism in the samples. The absolute values of the thermopower and electrical resistivity, and Raman spectra intensity of Mg 2 Si:Al dramatically diminished upon room-temperature compression. The calculated thermoelectric power factor of Mg 2 Si:Al raised with pressure to 2–3 GPa peaking in the maximum the values as high as about 8 × 10 −3 W/(K 2 m) and then gradually decreased with further compression. Raman spectroscopy studies indicated the crossovers near ∼5–7 and ∼11–12 GPa that are likely related to phase transitions. The data gathered suggest that Mg 2 Si:Al is metallized under moderate pressures between ∼5 and 12 GPa.

  19. Resonant Raman scattering in ion-beam-synthesized Mg2Si in a silicon matrix

    International Nuclear Information System (INIS)

    Baleva, M.; Zlateva, G.; Atanassov, A.; Abrashev, M.; Goranova, E.

    2005-01-01

    Resonant Raman scattering by ion beam synthesized in silicon matrix Mg 2 Si phase is studied. The samples are prepared with the implantation of 24 Mg + ions with dose 4x10 17 cm -2 and with two different energies 40 and 60 keV into (100)Si substrates. The far infrared spectra are used as criteria for the formation of the Mg 2 Si phase. The Raman spectra are excited with different lines of Ar + laser, with energies of the lines lying in the interval from 2.40 to 2.75 eV. The resonant scattering can be investigated using these laser lines, as far as according to the Mg 2 Si band structure, there are direct gaps with energies in the same region. The energy dependences of the scattered intensities in the case of the scattering by the allowed F 2g and the forbidden LO-type modes are experimentally obtained and theoretically interpreted. On the base of the investigation energies of the interband transitions in the Mg 2 Si are determined. It is found also that the resonant Raman scattering appears to be a powerful tool for characterization of a material with inclusions in it. In the particular case it is concluded that the Mg 2 Si phase is present in the form of a surface layer in the sample, prepared with implantation energy 40 keV and as low-dimensional precipitates, embedded in the silicon matrix, in the sample, prepared with the higher implantation energy

  20. Alternative route for the preparation of CoSb3 and Mg2Si derivatives

    International Nuclear Information System (INIS)

    Godlewska, E.; Mars, K.; Zawadzka, K.

    2012-01-01

    An alternative manufacturing route has been developed for cobalt triantimonide and magnesium disilicide derivatives. Elemental powders were mixed in stoichiometric proportions, cold pressed into cylindrical preforms and heated in oxygen-free environment to initiate the exothermic reaction. According to DTA/TG measurements and observations under high-temperature microscope, the onset of reaction occurred at a temperature not exceeding the melting point of the more volatile component, i.e. antimony in the case of CoSb 3 and magnesium in the case of Mg 2 Si. The reaction products were additionally heat treated to secure homogenization. Dense sinters were obtained by hot uniaxial pressing of the obtained powders in moderate temperature-and-pressure conditions. Several advantages were identified in the proposed technology: absence of liquid phases, relatively short time of the synthesis, possibility of in-situ or ex-situ doping and grain size control. - Graphical abstract: (1) Manufacturing flow sheet for CoSb 3 (milling included) and Mg 2 Si (no milling). (2) Micrographs of CoSb 3 product. (3) Micrographs of Mg 2 Si product. Highlights: ► The combustion synthesis followed by HP was used for the manufacturing of CoSb 3 or Mg 2 Si. ► The time of reaction is shorter compared with many other synthesis methods. ► The process is scalable and practically wasteless.

  1. THz characterization and demonstration of visible-transparent/terahertz-functional electromagnetic structures in ultra-conductive La-doped BaSnO3 Films.

    Science.gov (United States)

    Arezoomandan, Sara; Prakash, Abhinav; Chanana, Ashish; Yue, Jin; Mao, Jieying; Blair, Steve; Nahata, Ajay; Jalan, Bharat; Sensale-Rodriguez, Berardi

    2018-02-23

    We report on terahertz characterization of La-doped BaSnO 3 (BSO) thin-films. BSO is a transparent complex oxide material, which has attracted substantial interest due to its large electrical conductivity and wide bandgap. The complex refractive index of these films is extracted in the 0.3 to 1.5 THz frequency range, which shows a metal-like response across this broad frequency window. The large optical conductivity found in these films at terahertz wavelengths makes this material an interesting platform for developing electromagnetic structures having a strong response at terahertz wavelengths, i.e. terahertz-functional, while being transparent at visible and near-IR wavelengths. As an example of such application, we demonstrate a visible-transparent terahertz polarizer.

  2. Interface plasmon-phonons modes in ion-beam synthesized Mg2Si nanolayers

    International Nuclear Information System (INIS)

    Baleva, M.; Zlateva, G.

    2009-01-01

    Raman scattering of samples, representing n- and p-type Si matrix with unburied Mg 2 Si nanolayers, formed by ion-beam synthesis, are studied. Despite the features in the Raman spectra attributed to the polariton modes with frequencies between those of the TO and LO phonons, additional features outside this interval are detected. The frequencies of these features are very sensitive to the plasma frequency, being different in the n- and p-type Si matrix and to the annealing time. The latter implies the generation of interface plasmonphonons modes. The frequencies of the interface plasmon-phonon modes are calculated and compared with the experimental results. The order of the carrier concentration in Mg 2 Si, the data of which are not available in the literature, is evaluated. (authors)

  3. Contact resistance and stability study for Au, Ti, Hf and Ni contacts on thin-film Mg2Si

    KAUST Repository

    Zhang, Bo; Zheng, Tao; Wang, Qingxiao; Zhu, Yihan; Alshareef, Husam N.; Kim, Moon J.; Gnade, Bruce E.

    2016-01-01

    We present a detailed study of post-deposition annealing effects on contact resistance of Au, Ti, Hf and Ni electrodes on Mg2Si thin films. Thin-film Mg2Si and metal contacts were deposited using magnetron sputtering. Various post

  4. Technological Possibilities of Si:H Thin Film Deposition with Embedded Cubic Mg2Si Nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Galkin, N.G.; Galkin, K.N.; Chernev, I.M.; Fajgar, Radek; Stuchlíková, The-Ha; Remeš, Zdeněk; Stuchlík, Jiří

    2013-01-01

    Roč. 10, č. 12 (2013), s. 1712-1716 ISSN 1862-6351. [Asia-Pacific Conference on Green Technology with Silicides and Related Materials (APAC-SILICIDE 2013) /3./. Tsukuba, Ibaraki, 27.07.2013-29.07.2013] R&D Projects: GA ČR GA13-25747S Grant - others:MŠMT(CZ) LH12236; RFB(RU) 13-02-00046 Program:LH Institutional support: RVO:67985858 ; RVO:68378271 Keywords : Mg2Si * nanoparticles * technology Subject RIV: CA - Inorganic Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D)

  5. Polycrystalline Mg2Si thin films: A theoretical investigation of their electronic transport properties

    International Nuclear Information System (INIS)

    Balout, H.; Boulet, P.; Record, M.-C.

    2015-01-01

    The electronic structures and thermoelectric properties of a polycrystalline Mg 2 Si thin film have been investigated by first-principle density-functional theory (DFT) and Boltzmann transport theory calculations within the constant-relaxation time approximation. The polycrystalline thin film has been simulated by assembling three types of slabs each having the orientation (001), (110) or (111) with a thickness of about 18 Å. The effect of applying the relaxation procedure to the thin film induces disorder in the structure that has been ascertained by calculating radial distribution functions. For the calculations of the thermoelectric properties, the energy gap has been fixed at the experimental value of 0.74 eV. The thermoelectric properties, namely the Seebeck coefficient, the electrical conductivity and the power factor, have been determined at three temperatures of 350 K, 600 K and 900 K with respect to both the energy levels and the p-type and n-type doping levels. The best Seebeck coefficient is obtained at 350 K: the S yy component of the tensor amounts to about ±1000 μV K −1 , depending on the type of charge carriers. However, the electrical conductivity is much too small which results in low values of the figure of merit ZT. Structure–property relationship correlations based on directional radial distribution functions allow us to tentatively draw some explanations regarding the anisotropy of the electrical conductivity. Finally, the low ZT values obtained for the polycrystalline Mg 2 Si thin film are paralleled with those recently reported in the literature for bulk chalcogenide glasses. - Graphical abstract: Structure of the polycrystalline thin film of Mg 2 Si. - Author-Highlights: • Polycrystalline Mg 2 Si film has been modelled by DFT approach. • Thermoelectric properties have been evaluated by semi-classical Boltzmann theory. • The structure was found to be slightly disordered after relaxation. • The highest value of Seebeck

  6. The principal Hugoniot of Mg2SiO4 to 950 GPa

    Science.gov (United States)

    Townsend, J. P.; Root, S.; Shulenburger, L.; Lemke, R. W.; Kraus, R. G.; Jacobsen, S. B.; Spaulding, D.; Davies, E.; Stewart, S. T.

    2017-12-01

    We present new measurements and ab-initio calculations of the principal Hugoniot states of forsterite Mg2SiO4 in the liquid regime between 200-950 GPa.Forsterite samples were shock compressed along the principal Hugoniot using plate-impact shock compression experiments on the Sandia National Laboratories Z machine facility.In order to gain insight into the physical state of the liquid, we performed quantum molecular dynamics calculations of the Hugoniot and compare the results to experiment.We show that the principal Hugoniot is consistent with that of a single molecular fluid phase of Mg2SiO4, and compare our results to previous dynamic compression experiments and QMD calculations.Finally, we discuss how the results inform planetary accretion and impact models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  7. Enhancement of thermoelectric properties of Mg2Si compounds with Bi doping through carrier concentration tuning

    Science.gov (United States)

    Lee, Ji Eun; Cho, Sang-Hum; Oh, Min-Wook; Ryu, Byungi; Joo, Sung-Jae; Kim, Bong-Seo; Min, Bok-Ki; Lee, Hee-Woong; Park, Su-Dong

    2014-07-01

    The Bi-doped Mg2Si powder was fabricated with solid state reaction method and consolidated with hot pressing method and then its thermoelectric properties were investigated. The n-type transport properties were measured in all samples and temperature dependence of the electrical properties shows a behavior of degenerate semiconductors for Bi-doped samples. The electrical resistivity and the Seebeck coefficient were greatly reduced with Bi, which was mainly due to the increment of the carrier concentration. The samples have maximum carrier concentration of 8.2 × 1018 cm-3. The largest ZT value of 0.61 was achieve at 873 K for Mg2.04SiBi0.02. The Bi-doping was found to be an effective n-type dopant to adjust carrier concentration. [Figure not available: see fulltext.

  8. Thermodynamic properties of Mg2Si and Mg2Ge investigated by first principles method

    International Nuclear Information System (INIS)

    Wang, Hanfu; Jin, Hao; Chu, Weiguo; Guo, Yanjun

    2010-01-01

    The lattice dynamics and thermodynamic properties of Mg 2 Si and Mg 2 Ge are studied based on the first principles calculations. We obtain the phonon dispersion curves and phonon density of states spectra using the density functional perturbation theory with local density approximations. By employing the quasi-harmonic approximation, we calculate the temperature dependent Helmholtz free energy, bulk modulus, thermal expansion coefficient, specific heat, Debye temperature and overall Grueneisen coefficient. The results are in good agreement with available experimental data and previous theoretical studies. The thermal conductivities of both compounds are then estimated with the Slack's equation. By carefully choosing input parameters, especially the acoustic Debye temperature, we find that the calculated thermal conductivities agree fairly well with the experimental values above 80 K for both compounds. This demonstrates that the lattice thermal conductivity of simple cubic semiconductors may be estimated with satisfactory accuracy by combining the Slack's equation with the necessary thermodynamics parameters derived completely from the first principles calculations.

  9. Highly stable carbon coated Mg2Si intermetallic nanoparticles for lithium-ion battery anode

    Science.gov (United States)

    Tamirat, Andebet Gedamu; Hou, Mengyan; Liu, Yao; Bin, Duan; Sun, Yunhe; Fan, Long; Wang, Yonggang; Xia, Yongyao

    2018-04-01

    Silicon is an ideal candidate anode material for Li-ion batteries (LIBs). However, it suffers from rapid capacity fading due to large volume expansion upon lithium insertion. Herein, we design and fabricate highly stable carbon coated porous Mg2Si intermetallic anode material using facile mechano-thermal technique followed by carbon coating using thermal vapour deposition (TVD), toluene as carbon source. The electrode exhibits an excellent first reversible capacity of 726 mAh g-1 at a rate of 100 mA g-1. More importantly, the electrode demonstrates high rate capability (380 mAh g-1 at high rate of 2 A g-1) as well as high cycle stability, with capacity retentions of 65% over 500 cycles. These improvements are attributable to both Mg supporting medium and the uniform carbon coating, which can effectively increase the conductivity and electronic contact of the active material and protects large volume alterations during the electrochemical cycling process.

  10. Microstructure and mechanical properties of friction stir welded Al/Mg2Si metal matrix cast composite

    International Nuclear Information System (INIS)

    Nami, H.; Adgi, H.; Sharifitabar, M.; Shamabadi, H.

    2011-01-01

    In this research, friction stir weldability of 15 wt.% Mg 2 Si particulate aluminum matrix cast composite and effects of tool rotation speed and number of welding passes on microstructure and mechanical properties of the joints were investigated. Microstructural observations were carried out by employing optical and scanning electron microscopy of the cross sections perpendicular to the tool traverse direction. Mechanical properties including microhardness and tensile strength were evaluated in detail. The results showed fragmentation of Mg 2 Si particles and Mg 2 Si needles existing in eutectic structure in stir zone. Also, homogeneous distribution of Mg 2 Si particles was observed in the stir zone as a result of stirring with high plastic strains. Tension test results indicated that tensile strength of the joint had an optimum at 1120 rpm tool rotation speed and decreased with increasing of the number of welding passes. Hardness of the joint increased due to modification of solidification microstructure of the base composite. This research indicates that friction stir welding is a good candidate for joining of 15 wt.% Mg 2 Si aluminum matrix composite castings.

  11. Structure of Mg2SiO4 glass up to 140 GPa

    Science.gov (United States)

    Prescher, C.; Prakapenka, V.; Wang, Y.; Skinner, L. B.

    2014-12-01

    The physical properties of melts at temperature and pressure conditions of the Earth's mantle have a fundamental influence on the chemical and thermal evolution of the Earth. However, direct investigations of melt structures at these conditions are experimentally very difficult or even impossible with current capabilities. In order to still be able to obtain an estimate of the structural behavior of melts at high pressures and temperatures, amorphous materials have been widely used as analogue materials. In particular the investigation of sound wave velocities of amorphous SiO2 and MgSiO3 as analogues for silicate melts indicate structural changes at about ~30-40 GPa and ~130-140 GPa [1]. The transition pressures are lower for MgSiO3 than for SiO2 indicating that these transitions are affected by the degree of polymerization of the SiO2 network of the glasses. Nevertheless, these measurements only give a hint about the occurrence of structural transitions but lack information on the actual structural changes accompanied by the sound wave velocity discontinuities. The pressure of the second structural transition at ~130-140 GPa is of vital importance for geophysics. If it causes silicate melts to become denser than the surrounding solid material, it would result in negatively buoyant melts close to the core-mantle boundary, which could be a major factor affecting the chemical stratification of the Earth's mantle during an early magma ocean after the moon forming impact. In order to resolve the structural transition and estimate the effect of a different degree of polymerization further, we studied the structural behavior of Mg2SiO4 glass up to 140 GPa using X-ray total scattering and pair distribution function analysis. The measurements were performed at the GSECARS 13-IDD beamline at the APS employing the newly developed multichannel collimator (MCC) setup. The MCC effectively removes unwanted Compton scattering of the diamond anvils and enables easy extraction of

  12. Shock and Release Data on Forsterite (Mg2SiO4) Single Crystals

    Science.gov (United States)

    Root, S.; Townsend, J. P.; Shulenburger, L.; Davies, E.; Kraus, R. G.; Spaulding, D.; Stewart, S. T.; Jacobsen, S. B.; Mattsson, T. R.

    2016-12-01

    The Kepler mission has discovered numerous extra-solar rocky planets with sizes ranging from Earth-size to the super-Earths with masses 40 times larger than Earth. The solid solution series of (Mg, Fe)2SiO4 (olivine) is a major component in the mantle of Earth and likely these extra-solar rocky planets. However, understanding how the (Mg, Fe)2SiO4 system behaves at Earth like and super-Earth like pressures is still unknown. Using Sandia's Z machine facility, we shock compress single crystal forsterite, the Mg end-member of the olivine series. Solid aluminum flyers are accelerated up to 28 km/s to generate steady shock states up to 950 GPa. Release states from the Hugoniot are determined as well. In addition to experiments, we perform density functional theory (DFT) calculations to examine the potential phases along the Mg2SiO4 Hugoniot. We compare our results to other recent shock experiments on forsterite. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. Lattice stability and formation energies of intrinsic defects in Mg2Si and Mg2Ge via first principles simulations

    International Nuclear Information System (INIS)

    Jund, Philippe; Viennois, Romain; Tédenac, Jean-Claude; Colinet, Catherine; Hug, Gilles; Fèvre, Mathieu

    2013-01-01

    We report an ab initio study of the semiconducting Mg 2 X (with X = Si, Ge) compounds and in particular we analyze the formation energies of the different point defects with the aim of understanding the intrinsic doping mechanisms. We find that the formation energy of Mg 2 Ge is 50% larger than that of Mg 2 Si, in agreement with the experimental tendency. From a study of the stability and the electronic properties of the most stable defects, taking into account the growth conditions, we show that the main cause of the n doping in these materials comes from interstitial magnesium defects. Conversely, since other defects acting like acceptors such as Mg vacancies or multivacancies are more stable in Mg 2 Ge than in Mg 2 Si, this explains why Mg 2 Ge can be of n or p type, in contrast to Mg 2 Si. The finding that the most stable defects are different in Mg 2 Si and Mg 2 Ge and depend on the growth conditions is important and must be taken into account in the search for the optimal doping to improve the thermoelectric properties of these materials.

  14. Analysis of thermoluminescence kinetics of Mg2SiO4:Tb compounds employing an interactive model

    International Nuclear Information System (INIS)

    Marcazzo, J.; Prokic, M.; Santiago, M.; Molina, P.; Caselli, E.

    2009-01-01

    The kinetics involved in the thermoluminescence (TL) of Mg 2 SiO 4 :Tb compounds has been investigated by unfolding glow curves employing both the General Order model and a model that takes into account interactions among traps. The dependence of the glow curve shape on dose is only correctly described if interaction among traps is included in the analysis.

  15. Prediction study on mechanical and thermodynamic properties of orthorhombic Mg2SiO4 under high temperature

    International Nuclear Information System (INIS)

    Zhou, Jianting; Zhang, Hong; Chen, Yue; Shong, Jun; Chen, Zhuo; Yang, Juan; Zheng, Zhou; Wang, Feng

    2014-01-01

    In this work, based on density functional theory and quasi-harmonic Debye model, mechanical and thermodynamic properties of orthorhombic Mg 2 SiO 4 under high temperature are predicted. We found out that α-Mg 2 SiO 4 is mechanically stable under the condition from about 0 to 74 GPa. Results indicate that the main cause of mechanical instability is high pressure, and the effect caused by high temperature is small. C 11 , C 22 , C 33 , B and v p reduce with temperature just a little and increase with pressure obviously. Mg 2 SiO 4 has excellent resistance to strong compression; however the resistance to shear is unsatisfactory. The C v tends to the Petit and Dulong limit at high temperature under any pressure, and it is proportional to T 3 at extremely low temperature. Pressure has an opposite effect on C v than temperature. The suppressed effect on C v caused by pressure is not obvious under low and very high temperature. Mg 2 SiO 4 has three different thermal expansion coefficients (α) along a-, b- and c-axes, and α a <α c <α b . α increases rapidly at low temperature (about <300 K), and slows down at high temperature. High pressure would greatly suppress expansion caused by temperature. Nevertheless, increasing tendency of α b and α c is still obvious under high pressure, especially α b . All the properties are mainly due to Si–O covalent bonds and their directions

  16. Experimental studies on mechanical properties of T6 treated Al25Mg2Si2Cu4Fe alloy

    Science.gov (United States)

    Sondur, D. G.; Mallapur, D. G.; Udupa, K. Rajendra

    2018-04-01

    Effect of T6 treatment on the mechanical properties of Al25Mg2Si2Cu4Fe alloy was evaluated by conducting mechanical tests on test pieces using universal testing machine. Increase in the mechanical properties such as ultimate tensile strength, hardness and % elongation was observed. Microstructure characterization revealed the modification in the size and shapes of the precipitates formed during the homogenization process. This modification increases the anisotropy of the microstructure and the stresses in the as cast structure. The increase in the hardness of T6 treated alloy is due to the partial recrystallization, fragmentation and redistribution of primary Mg2Si phase, precipitation of fine θ, Q phases. The high volume fractions of uniformly dispersed hard β-particles greatly increase the flow stress and provide an appreciable impediment to plastic deformation. Thus increasing the hardness of the alloy.

  17. Synthesis, mechanical properties and corrosion behavior of powder metallurgy processed Fe/Mg2Si composites for biodegradable implant applications.

    Science.gov (United States)

    Sikora-Jasinska, M; Paternoster, C; Mostaed, E; Tolouei, R; Casati, R; Vedani, M; Mantovani, D

    2017-12-01

    Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg 2 Si particles were proposed. The initial powders were prepared by different combinations of mixing and milling processes, and finally consolidated by hot rolling. The influence of the microstructure on mechanical properties and corrosion behavior of Fe/Mg 2 Si was investigated. Scanning electron microscopy and X-ray diffraction were used for the assessment of the composite structure. Tensile and hardness tests were performed to characterize the mechanical properties. Potentiodynamic and static corrosion tests were carried out to investigate the corrosion behavior in a pseudo-physiological environment. Samples with smaller Mg 2 Si particles showed a more homogenous distribution of the reinforcement. Yield and ultimate tensile strength increased when compared to those of pure Fe (from 400MPa and 416MPa to 523MPa and 630MPa, respectively). Electrochemical measurements and immersion tests indicated that the addition of Mg 2 Si could increase the corrosion rate of Fe even twice (from 0.14 to 0.28mm·year -1 ). It was found that the preparation method of the initial composite powders played a major role in the corrosion process as well as in the corrosion mechanism of the final composite. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Contact resistance and stability study for Au, Ti, Hf and Ni contacts on thin-film Mg2Si

    KAUST Repository

    Zhang, Bo

    2016-12-28

    We present a detailed study of post-deposition annealing effects on contact resistance of Au, Ti, Hf and Ni electrodes on Mg2Si thin films. Thin-film Mg2Si and metal contacts were deposited using magnetron sputtering. Various post-annealing temperatures were studied to determine the thermal stability of each contact metal. The specific contact resistivity (SCR) was determined using the Cross Bridge Kelvin Resistor (CBKR) method. Ni contacts exhibits the best thermal stability, maintaining stability up to 400 °C, with a SCR of approximately 10−2 Ω-cm2 after annealing. The increased SCR after high temperature annealing is correlated with the formation of a Mg-Si-Ni mixture identified by cross-sectional scanning transmission electron microscopy (STEM) characterization, X-ray diffraction characterization (XRD) and other elemental analyses. The formation of this Mg-Si-Ni mixture is attributed to Ni diffusion and its reaction with the Mg2Si film.

  19. Microstructure and Mechanical Properties of Dissimilar Joints of Al-Mg2Si and 5052 Aluminum Alloy by Friction Stir Welding

    Science.gov (United States)

    Huang, B. W.; Qin, Q. D.; Zhang, D. H.; Wu, Y. J.; Su, X. D.

    2018-03-01

    Al-Mg2Si alloy and 5052 Al alloy were welded successfully by friction stir welding (FSW) in this study. The results show that the alloy consists of three distinct zones after FSW: the base material zone (BMZ), the transitional zone, and the weld nugget (WN). The morphologies of the primary Mg2Si phases are identified as coarse equiaxed crystals for Al-Mg2Si alloys in the BMZ. The WN is a mixture of rich Al-Mg2Si and rich 5052 alloy, and a banded structure is formed in the zone. Interestingly, in the WN, the equiaxed crystals changed to polygonal particles with substantially reduced sizes in the rich Al-Mg2Si zone. However, in addition to the white rich Mg phase appearing in the rich 5052 zone near the interface, the 5052 alloy does not show obvious changes. The hardness gradually increases from the BMZ of the 5052 to the welded joint to the Al-Mg2Si BMZ. In addition, the ultimate tensile strength (UTS) of the welded joint is higher than that of the base material of the Al-Mg2Si, whereas it is lower than that of the 5052 base alloy. The results of the elongation are similar to the UTS results. The fracture mechanism is also investigated.

  20. Effect of magnesium content on the microstructure and dry sliding wear behavior of centrifugally cast functionally graded A356-Mg2Si in situ composites

    Science.gov (United States)

    Ram, Subhash Chandra; Chattopadhyay, K.; Chakrabarty, I.

    2018-04-01

    Functionally graded A356 alloy (Al–7.2Si–0.3Mg) –Mg2Si in situ composites have been synthesized via centrifugal casting route. Mg2Si particles tend to migrate towards the core of the tubular product by centrifugal force. The in situ formed Mg2Si particles in composites are characterized by x-ray diffraction (XRD) analysis, Energy dispersive spectrometry (EDS), Optical, Scanning Electron and Transmission Electron Microscopy. Apart from primary blocky Mg2Si particles the matrix contains other phases viz. Al-Si eutectic, pseudo-binary Al-Mg2Si eutectic and Al-Fe-Si intermetallics. Density is found to decrease and %porosity is increased with increase in volume fraction of Mg2Si. Maximum hardness was observed at the inner core region due to maximum segregation of Mg2Si particles and gradually decreases towards the outer periphery region. The dry sliding wear was evaluated with varying parameters such as normal loads (N) and sliding distances (m). A substantial increase in wear resistance at the inner core region is observed. From the worn surface characterization, the wear mechanisms have been explained.

  1. Centrifugally cast Zn-27Al-xMg-ySi alloys and their in situ (Mg2Si + Si)/ZA27 composites

    International Nuclear Information System (INIS)

    Wang Qudong; Chen Yongjun; Chen Wenzhou; Wei Yinhong; Zhai Chunquan; Ding Wenjiang

    2005-01-01

    Effects of composition, mold temperature, rotating rate and modification on microstructure of centrifugally cast Zn-27Al-xMg-ySi alloys have been investigated. In situ composites of Zn-27Al-6.3Mg-3.7Si and Zn-27Al-9.8Mg-5.2Si alloys were fabricated by centrifugal casting using heated permanent mold. These composites consist of three layers: inner layer segregates lots of blocky primary Mg 2 Si and a litter blocky primary Si, middle layer contains without primary Mg 2 Si and primary Si, outer layer contains primary Mg 2 Si and primary Si. The position, quantity and distribution of primary Mg 2 Si and primary Si in the composites are determined jointly by alloy composition, solidification velocity under the effect of centrifugal force and their floating velocity inward. Na salt modifier can refine grain and primary Mg 2 Si and make primary Mg 2 Si distribute more evenly and make primary Si nodular. For centrifugally cast Zn-27Al-3.2Mg-1.8Si alloy, the microstructures of inner layer, middle layer and outer layer are almost similar, single layer materials without primary Mg 2 Si and primary Si are obtained, and their grain sizes increased with the mold temperature increasing

  2. On the way to enhance the optical absorption of a-Si in NIR by embedding Mg_2Si thin film

    International Nuclear Information System (INIS)

    Chernev, I. M.; Shevlyagin, A. V.; Galkin, K. N.; Stuchlik, J.; Remes, Z.; Fajgar, R.; Galkin, N. G.

    2016-01-01

    Mg_2Si thin film was embedded in amorphous silicon matrix by solid phase epitaxy. The structure and optical properties were investigated by electron energy loss, X-ray photoelectron, Raman, and photo thermal deflection spectroscopy measurements. It was found that in the photon energy range of 0.8–1.7 eV, the light absorption of the structure with magnesium silicide (Mg_2Si) film embedded in a-Si(i) matrix is 1.5 times higher than that for the same structure without Mg_2Si.

  3. Microstructure and mechanical properties of diffusion bonded Al/Mg2Si metal matrix in situ composite

    International Nuclear Information System (INIS)

    Nami, H.; Halvaee, A.; Adgi, H.; Hadian, A.

    2010-01-01

    In this research, Al/Mg 2 Si composite produced by gravity casting, was joined by diffusion welding technique at 6 MPa pressure with various welding temperatures and durations. This metal matrix composite (MMC) containing 15% Mg 2 Si particles was produced by in situ technique. Specific diffusion bonding process was introduced as a low vacuum technique. Microstructure and shear strength of the joined areas were determined. Scanning electron microscopy examination was carried out on the welded interfaces and shear tests were conducted to the samples interface to find out the effect of welding temperatures and durations on the weldability. It was found that high welding temperatures resulted in increase of shear strength. However, increase in welding duration did not make any detectable changes. The bonded interface could be developed as a wavy state depending on the amount of parent material deformation that was associated with bonding temperature. Results indicated that MMC can be joined by diffusion welding technique successfully with satisfactory shear strength.

  4. Effect of Bi modification treatment on microstructure, tensile properties, and fracture behavior of cast Al-Mg2Si metal matrix composite

    Directory of Open Access Journals (Sweden)

    Wu Xiaofeng

    2013-01-01

    Full Text Available Bi has a good modification effect on the hypoeutectic Al-Si alloy, and the morphology of eutectic Si changes from coarse acicular to fine fibrous. Based on the similarity between Mg2Si and Si phases in crystalline structure and crystallization process, the present study investigated the effects of different concentrations of Bi on the microstructure, tensile properties, and fracture behavior of cast Al-15wt.%Mg2Si in-situ metal matrix composite. The results show that the addition of the proper amount of Bi has a significant modification effect on both primary and eutectic Mg2Si in the Al-15wt.%Mg2Si composite. With an increase in Bi content from 0 to 1wt.%, the morphology of the primary Mg2Si is changed from irregular or dendritic to polyhedral shape; and its average particle size is significantly decreased from 70 to 6 μm. Moreover, the morphology of the eutectic Mg2Si phase is altered from flake-like to very short fibrous or dot-like. When the Bi addition exceeds 4.0wt.%, the primary Mg2Si becomes coarse again. However, the eutectic Mg2Si still exhibits the modified morphology. Tensile tests reveal that the Bi addition can improve the tensile strength and ductility of the material. Compared with those of the unmodified composite, the ultimate tensile strength and percentage elongation after fracture with 1.0wt.% Bi increase 51.2% and 100%, respectively. At the same time, the Bi addition changes the fracture behavior from brittle to ductile.

  5. The influence of Ni addition and hot-extrusion on the microstructure and tensile properties of Al–15%Mg2Si composite

    International Nuclear Information System (INIS)

    Emamy, M.; Khodadadi, M.; Honarbakhsh Raouf, A.; Nasiri, N.

    2013-01-01

    Highlights: ► Ni content on the microstructure and tensile properties of Al–Mg 2 Si composite. ► Ni changed the size of primary Mg 2 Si from 42 μm to 17 μm. ► Higher UTS and elongation values obtained by addition of 5 wt% Ni. ► Fracture behavior changed from brittle to ductile by Ni addition and extrusion. - Abstract: The effects of nickel addition and hot-extrusion on the microstructure and tensile properties of in situ Al–15%Mg 2 Si composite specimens have been investigated. Al–15%Mg 2 Si composite ingots were prepared by an in situ process and different amounts of nickel (0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 wt% Ni) were added to the remelted composite. Optical microscopy (OM) and scanning electron microscopy (SEM) indicated that Ni addition changes the morphology of both primary and eutectic Mg 2 Si phases and decreases the size of primary Mg 2 Si particles from 42 μm to 17 μm. Hot-extrusion was found to be powerful in breaking the eutectic network and changing the size and morphology of pseudo-eutectic Mg 2 Si phase. The results obtained from tensile testing revealed that both Ni addition and hot-extrusion process improve ultimate tensile strength (UTS) and elongation values. Fracture surface examinations revealed a transition from brittle fracture mode in as-cast composite to ductile fracture in hot-extruded composite after Ni addition. This can be attributed to the changes in size and morphology of primary and eutectic Mg 2 Si phases and also the formation of more and finer α-Al phase

  6. Heterogeneous nucleation of Mg2Si on Sr11Sb10 nucleus in Mg–x(3.5, 5 wt.%)Si–1Al alloys

    International Nuclear Information System (INIS)

    Wang, Hui-Yuan; Chen, Lei; Liu, Bo; Li, Xiao-Ran; Wang, Jin-Guo; Jiang, Qi-Chuan

    2012-01-01

    After combined additions of Sr and Sb, most primary Mg 2 Si crystals in Mg–3.5Si–1Al and Mg–5Si–1Al alloys transformed from equiaxed-dendritic shapes to octahedral morphologies; while eutectic phases also changed from Chinese script to short rod-shapes. The mechanisms of complex modification of Sr and Sb were attributed to the heterogeneous nucleation of primary Mg 2 Si on Sr 11 Sb 10 nucleus, together with change in growth manners caused by incorporation of Sb in Mg 2 Si crystals. -- Highlights: ► The Sr 11 Sb 10 is the heterogeneous nucleation of primary Mg 2 Si in Mg–3.5Si–1Al alloys. ► Some Sb atoms were incorporated by substituting Si which changed growth manners of primary Mg 2 Si. ► Primary Mg 2 Si transformed from equiaxed-dendritic to octahedral after modification. ► Eutectic phases changed from Chinese script to short rod-shapes after modification.

  7. Gamma radiation induced sensitization and photo-transfer in Mg2SiO4:Tb TLD phosphor

    International Nuclear Information System (INIS)

    Lakshmanan, A.R.; Vohra, K.G.

    1979-01-01

    Mg 2 SiO 4 :Tb TLD phosphor was found to show enhanced TL sensitivity to both gamma and UV radiations after high pre-gamma exposures (>100 R) and a post-annealing treatment at 300 0 C for 1 h. Maximum sensitization factors of 2.8 and 55 were obtained at the pre-expsoure levels of 5.2x10 1 C/kg and 1.3x10 3 C/kg for gamma and UV test radiations respectively. The near constancy of the intensity of the residual TL (RTL) peak at 500 0 C for the sensitized sample with increasing test-gamma exposures has ruled out the re-trapping model proposed earlier for the gamma radiation induced sensitization in this phosphor. The Tsub(max) for the sensitized phosphor was found to occur at a higher temperature compared to that for the virgin phosphor. The dependence of sensitization on RTL was explained qualitatively on the basis of competition between sensitization traps (having higher energy than the dosimetry traps) and RTL traps while capturing the charge carriers generated during the test-gamma exposure. The sensitization observed in this phosphor to UV test radiation was found to be a consequence of the photo-transfer of charge carriers from deep (RTL) traps to the shallow (dosimetry) traps. The reduction in RTL peak (500 0 C) intensity of the sensitized sample with increasing test-UV exposure has demonstrated the photo-transfer mechanism in this phosphor. The TL response of the virgin Mg 2 SiO 4 :Tb phosphor was found to be supralinear to both gamma and UV radiations. The TL response of the sensitized phosphor was found to be linear to gamma radiation and sublinear to UV radiation. (Auth.)

  8. Effect of reinforcement amount, mold temperature, superheat, and mold thickness on fluidity of in-situ Al-Mg2Si composites

    Directory of Open Access Journals (Sweden)

    Reza Vatankhah Barenji

    2018-01-01

    Full Text Available In the present study, the effects of mold temperature, superheat, mold thickness, and Mg2Si amount on the fluidity of the Al-Mg2Si as-cast in-situ composites were investigated using the mathematical models. Composites with different amounts of Mg2Si were fabricated, and the fluidity and microstructure of each were then analyzed. For this purpose, the experiments were designed using a central composite rotatable design, and the relationship between parameters and fluidity were developed using the response surface method. In addition, optical and scanning electron microscopes were used for microstructural observation. The ANOVA shows that the mathematical models can predict the fluidity accurately. The results show that by increasing the mold temperature from 25 °C to 200 °C, superheat from 50 °C to 250 °C, and thickness from 3 mm to 12 mm, the fluidity of the composites decreases, where the mold thickness is more effective than other factors. In addition, the higher amounts of Mg2Si in the range from 15wt.% to 25wt.% lead to the lower fluidity of the composites. For example, when the mold temperature, superheat, and thickness are respectively 100 °C, 150 °C, and 7 mm, the fluidity length is changed in the range of 11.9 cm to 15.3 cm. By increasing the amount of Mg2Si, the morphology of the primary Mg2Si becomes irregular and the size of primary Mg2Si is increased. Moreover, the change of solidification mode from skin to pasty mode is the most noticeable microstructural effect on the fluidity.

  9. Lattice-dynamical estimation of atomic thermal parameters for silicates: Forsterite α-Mg2SiO4

    International Nuclear Information System (INIS)

    Pilati, T.; Bianchi, R.; Gramaccioli, C.M.

    1990-01-01

    As an example of extending harmonic lattice-dynamical procedures to silicates, the atomic thermal parameters for forsterite Mg 2 SiO 4 , an important constituent of earth's crust, have been calculated on this basis. For this purpose, Iishi's rigid-ion model was used, with slight modifications. Although such potentials were derived exclusively from fitting IR and Raman-active frequencies, the reproduction of the phonon-dispersion curves is good, and the calculation of thermodynamic functions such as entropy provides values which are near to calorimetric estimates. The calculated atomic thermal parameters are in good agreement with the experimental values reported by most authors. The calculations at various temperatures show the effect of zero-point motion very clearly: its contribution to temperature factors is about half of the total at room temperature. Bond-length corrections for thermal libration can be applied using the general-case formula: these amount to 0.003 A for the Si-O bonds at room temperature. Although the thermal parameters in the SiO 4 group fit a rigid-body model, the correction obtained using the Schomaker-Trueblood procedure gives a significantly different result: this is essentially due to the weak librational character of the motion of silicate groups in the structure. (orig.)

  10. Effect of T6 treatment on the coefficient of friction of Al25Mg2Si2Cu4Fe alloy

    Science.gov (United States)

    Sondur, D. G.; Mallapur, D. G.; Udupa, K. Rajendra

    2018-04-01

    Effect of T6 treatment on the coefficient of friction of Al25Mg2Si2Cu4Fe alloy was evaluated by conducting wear test on pin on disc wear testing machine. Wear test parameters such as the load and the speed were varied by keeping one constant and varying the other respectively. It was observed that the coefficient of friction is high for as cast condition due to the brittle microstructure. After T6 heat treatment the precipitates formed such as the Chinese scripts and the Mg2Si blocks got modified that lead to improvement in the hardness and the wear resistance. This reduces the coefficient of friction.

  11. Wear behavioral study of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load

    Science.gov (United States)

    Harlapur, M. D.; Sondur, D. G.; Akkimardi, V. G.; Mallapur, D. G.

    2018-04-01

    In the current study, the wear behavior of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy has been investigated. Microstructure, SEM and EDS results confirm the presence of different intermetallic and their effects on wear properties of Al25Mg2Si2Cu4Ni alloy in as cast as well as aged condition. Alloying main elements like Si, Cu, Mg and Ni partly dissolve in the primary α-Al matrix and to some amount present in the form of intermetallic phases. SEM structure of as cast alloy shows blocks of Mg2Si which is at random distributed in the aluminium matrix. Precipitates of Al2Cu in the form of Chinese script are also observed. Also `Q' phase (Al-Si-Cu-Mg) be distributed uniformly into the aluminium matrix. Few coarsened platelets of Ni are seen. In case of 7 hr homogenized samples blocks of Mg2Si get rounded at the corners, Platelets of Ni get fragmented and distributed uniformly in the aluminium matrix. Results show improved volumetric wear resistance and reduced coefficient of friction after homogenizing heat treatment.

  12. Thermal Treatment, Sliding Wear and Saline Corrosion of Al In Situ Reinforced with Mg2Si and Ex Situ Reinforced with TiC Particles

    Science.gov (United States)

    Lekatou, A. G.; Poulia, A.; Mavros, H.; Karantzalis, A. E.

    2018-02-01

    The main objective of this work is to produce a composite consisting of (a) a cast heat-treatable Al-Mg-Si alloy with high contents of Mg for corrosion resistance and Si to offset the Mg-due poor castability (in situ hypoeutectic Mg2Si/Al composite) and (b) TiC particles at high enough volume fractions (≤ 15%), in order to achieve a satisfactory combination of wear and corrosion performance. TiCp/Al-7Mg-5Si (wt.%) composites were produced by flux-assisted casting followed by solution and aging heat treatment. Solution treatment led to a relatively uniform dispersion and shape rounding of Mg2Si precipitates and Si particles. TiC particle addition resulted in refinement of primary Al, modification of the Mg2Si Chinese script morphology and refinement/spheroidization of primary Mg2Si. Heat treatment combined with TiC addition notably improved the sliding wear resistance of Al-7Mg-5Si. A wear mechanism has been proposed. The TiC/Al interfaces remained intact of corrosion during potentiodynamic polarization of the heat-treated materials in 3.5 wt.% NaCl. Different main forms of localized corrosion in 3.5 wt.% NaCl were identified for each TiC content (0, 5, 15 vol.%), depending on specific degradation favoring microstructural features (topology/size/interface wetting) at each composition.

  13. The effect of Fe-rich intermetallics on the microstructure, hardness and tensile properties of Al–Mg2Si die-cast composite

    International Nuclear Information System (INIS)

    Emamy, M.; Emami, A.R.; Khorshidi, R.; Ghorbani, M.R.

    2013-01-01

    Highlights: ► Effect of Fe on the microstructure and mechanical properties of Al–Mg 2 Si composite. ► Fe changed the size of primary Mg 2 Si from 33 μm to 15 μm. ► Higher hardness, YS, UTS and Quality Index values obtained from Fe addition. ► Different morphologies of Fe-intermetallics were found with higher Fe contents. - Abstract: In present paper, an attempt was made to examine the effect of different concentrations of Fe (0.5, 1, 1.5, 2 and 3 wt.%) on the microstructure and tensile properties of an in situ Al–15wt.%Mg 2 Si metal matrix composite (MMC). The composite was made by casting process and characterized by optical microscope, scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy. The results depicted that the addition of 2 wt.% Fe to the MMC changes the morphology of primary Mg 2 Si from irregular to polyhedral shape and reduces its average particle size from 33 μm to 15 μm. The microstructural studies also showed that the addition of Fe leads to the formation of Fe-rich intermetallics with polyhedral, plate-like and star-like morphology. Hardness results demonstrated that Fe addition to Al–15%Mg 2 Si composite has a positive effect on the hardness improvement. Further investigations on tensile tests revealed optimum Fe (1 wt.%) level for improving tensile properties. In the point of fracture behavior of the composite, Fe-containing specimens showed a brittle mode of failure

  14. Mechanical Properties and Fabrication of Nanostructured Mg_2SiO_4-MgAl_2O_4 Composites by High-Frequency Induction Heated Combustion

    International Nuclear Information System (INIS)

    Shon, In-Jin; Kang, Hyun-Su; Hong, Kyung-Tae; Doh, Jung-Mann; Yoon, Jin-Kook

    2011-01-01

    Nanopowders of MgO, Al_2O_3 and SiO_2 were made by high energy ball milling. The rapid sintering of nanostructured MgAl_2O_4-Mg_2SiO_4 composites was investigated by a high-frequency induction heating sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. As nanomaterials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. Highly dense nanostructured MgAl_2O_4-Mg_2SiO_4 composites were produced with simultaneous application of 80 MPa pressure and induced output current of total power capacity (15 kW) within 2 min. The sintering behavior, gain size and mechanical properties of MgAl_2O_4-Mg_2SiO_4 composites were investigated.

  15. LOW-TEMPERATURE SINTERED (ZnMg2SiO4 MICROWAVE CERAMICS WITH TiO2 ADDITION AND CALCIUM BOROSILICATE GLASS

    Directory of Open Access Journals (Sweden)

    BO LI

    2011-03-01

    Full Text Available The low-temperature sintered (ZnMg2SiO–TiO2 microwave ceramic using CaO–B2O3–SiO2 (CBS as a sintering aid has been developed. Microwave properties of (Zn1-xMgx2SiO4 base materials via sol-gel method were highly dependent on the Mg-substituted content. Further, effects of CBS and TiO2 additives on the crystal phases, microstructures and microwave characteristics of (ZnMg2SiO4 (ZMS ceramics were investigated. The results indicated that CBS glass could lower the firing temperature of ZMS dielectrics effectively from 1170 to 950°C due to the liquid-phase effect, and significantly improve the sintering behavior and microwave properties of ZMS ceramics. Moreover, ZMS–TiO2 ceramics showed the biphasic structure and the abnormal grain growth was suppressed by the pinning effect of second phase TiO2. Proper amount of TiO2 could tune the large negative temperature coefficient of resonant frequency (tf of ZMS system to a near zero value. (Zn0.8Mg0.22SiO4 codoped with 10 wt.% TiO2 and 3 wt.% CBS sintered at 950°C exhibits the dense microstructure and excellent microwave properties: εr = 9.5, Q·f = 16 600 GHz and tf = −9.6 ppm/°C.

  16. Calibration of Mg2SiO4(Tb) thermoluminescent dosimeters for use in determining diagnostic X-ray doses to Adult Health Study participants

    International Nuclear Information System (INIS)

    Kato, Kazuo; Antoku, Shigetoshi; Sawada, Shozo; Russell, W.J.

    1989-11-01

    Characteristics of Mg 2 SiO 4 (Tb) thermoluminescent dosimeters (TLD) were ascertained preparatory to measuring dose from diagnostic X-ray examinations received by Adult Health Study participants. These detectors are small, relatively sensitive to low-dose X rays, and are appropriate for precise dosimetry. Extensive calibration is necessary for precisely determining doses according to their thermoluminescent intensities. Their sensitivities were investigated, by dose according to X-ray tube voltage, and by exposure direction, to obtain directional dependence. Dosimeter sensitivity lessened due to the fading effect and diminution of the planchet. However, these adverse effects can be avoided by storing the dosimeters at least 1.5 hours and by using fresh silver-plated planchets. Thus, the TLDs, for which sensitivities were determined in this study, will be useful in subsequent diagnostic X-ray dosimetry. (author)

  17. Enstatite, Mg2Si2O6: A neutron diffraction refinement of the crystal structure and a rigid-body analysis of the thermal vibration

    International Nuclear Information System (INIS)

    Ghose, S.; Schomaker, V.; McMullan, R.K.

    1986-01-01

    Synthetic enstatite, Mg 2 Si 2 O 6 , is orthorhombic, space group Pbca, with eight formula units per cell and lattice parameters a = 18.235(3), b = 8.818(1), c = 5.179(1) A at 23 0 C. A least-squares structure refinement based on 1790 neutron intensity data converged with an agreement factor R(F 2 ) = 0.032, yielding Mg-O and Si-O bond lengths with standard deviations of 0.0007 and 0.0008 A, respectively. The variations observed in the Si-O bond lengths within the silicate tetrahedra A and B are caused by the differences in primary coordination of the oxygen atoms and the proximity of the magnesium ions to the silicon atoms. The latter effect is most pronounced for the bridging bonds of tetrahedron. A. The smallest O-Si-O angle is the result of edge-sharing by the Mg(2) octahedron and the A tetrahedron. An analysis of rigid-body thermal vibrations of the two crystallographically independent [SiO 4 ] tetrahedra indicates considerable librational motion, leading to a thermal correction of apparent Si-O bond lengths as large as +0.002 A at room temperature. (orig.)

  18. Experimental analysis of volumetric wear behavioural and mechanical properties study of as cast and 1Hr homogenized Al-25Mg2Si2Cu4Ni alloy at constant load

    Science.gov (United States)

    Harlapur, M. D.; Mallapur, D. G.; Udupa, K. Rajendra

    2018-04-01

    In the current study, an experimental analysis of volumetric wear behaviour and mechanical properties of aluminium (Al-25Mg2Si2Cu4Ni) alloy in as cast and 1Hr homogenized with T6 heat treatment is carried out at constant load. Pin-on-disc apparatus was used to carry out sliding wear test. Mechanical properties such as tensile, hardness and compression test on as-cast and 1 hr homogenized samples are measured. Universal testing machine was used to conduct the tensile and compressive test at room temperature. Brinell hardness tester was used to conduct the hardness test. The scanning electron microscope was used to analyze the worn-out wear surfaces. Wear results and mechanical properties shows that 1Hr homogenized Al-25Mg2Si2Cu4Ni alloy samples with T6 treated had better volumetric wear resistance, hardness, tensile and compressive strength as compared to as cast samples.

  19. An orange emitting phosphor Lu2−xCaMg2Si2.9Ti0.1O12:xCe with pure garnet phase for warm white LEDs

    International Nuclear Information System (INIS)

    Chu, Yaoqing; Zhang, Qinghong; Xu, Jiayue; Li, Yaogang; Wang, Hongzhi

    2015-01-01

    A new silicate garnet phosphor, Lu 2−x CaMg 2 Si 2.9 Ti 0.1 O 12 :xCe was synthesized by a high temperature solid-state reaction under reductive atmosphere. X-ray diffraction (XRD) showed that the powder was pure garnet phase. The emission and excitation spectrum indicated that the Lu 2−x CaMg 2 Si 2.9 Ti 0.1 O 12 :xCe phosphors could absorb blue light in the spectral range of 400–550 nm efficiently and exhibit bright yellow–orange emission in the range of 520–750 nm. With the increase of Ce 3+ concentration, the emission band of Ce 3+ showed a red shift. Interestingly, the concentration quenching occurred when the Ce 3+ concentration exceeded 4 mol%. The temperature-dependent luminescent properties of the phosphors were discussed and the Lu 1.96 CaMg 2 Si 2.9 Ti 0.1 O 12 :0.04Ce phosphors showed good performances in color temperature (2430 K) and potential applications for warm white LEDs. - Graphical Abstract: This image shows that the phosphor of Lu 1.96 CaMg 2 Si 2.9 Ti 0.1 O 12 :0.04Ce can generate a uniform yellow tint under natural light illumination and emit orange–red light when excited by blue light. With a fixed 467 nm emission light, warm white light can be produced by this phosphor, which indicates that the phosphor is potentially applicable in warm white light emitting diodes based on GaN chips. - Highlights: • A new silicate garnet phosphor was synthesized by solid-state method. • Secondary phases can be avoided when a small amount of Si 4+ were replaced by Ti 4+ . • A broad emission band of Ce 3+ in the phosphors was described. • The phosphors are potentially applicable in warm white light emitting diodes

  20. Experimental wear behavioral studies of as-cast and 5 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load based on taguchi method

    Science.gov (United States)

    Harlapur, M. D.; Mallapur, D. G.; Udupa, K. Rajendra

    2018-04-01

    In the present study, an experimental study of the volumetric wear behaviour of Aluminium (Al-25Mg2Si2Cu4Ni) alloy in as cast and 5Hr homogenized with T6 heat treatment is carried out at constant load. The Pin on disc apparatus was used to carry out the sliding wear test. Taguchi method based on L-16 orthogonal array was employed to evaluate the data on the wear behavior. Signal-to-noise ratio among the objective of smaller the better and mean of means results were used. General regression model is obtained by correlation. Lastly confirmation test was completed to compose a comparison between the experimental results foreseen from the mention correlation. The mathematical model reveals the load has maximum contribution on the wear rate compared to speed. Scanning Electron Microscope was used to analyze the worn-out wear surfaces. Wear results show that 5Hr homogenized Al-25Mg2Si2Cu4Ni alloy samples with T6 treated had better volumetric wear resistance as compared to as cast samples.

  1. Synthesis and pressure effects on the La doped CaFe{sub 2}As{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Soo Hyun; Park, Tuson [Dept. of physics, Sungkyunkwan University, Suwon (Korea, Republic of); Shang, T.; Yuan, H. Q. [Dept. of physics, Zhejiang University, Hangzhou (China)

    2014-09-15

    We have synthesized La doped CaFe2As{sub 2} single crystals with Sn flux in an evacuated quartz ampule. Doping and pressure effects on the magnetic and superconducting properties of the under-doped Ca{sub 1-x}La{sub x}Fe{sub 2}As{sub 2} (x=0.08, 0.1) were studied by measuring electrical resistivity under quasi-hydrostatic pressure up to 21 kbar. Magnetic transition temperatures for all studied concentrations were sharply suppressed with slight amplitude of pressure, less than 3 kbar, while superconducting transition temperatures were robust against pressure. In this communication, we report temperature-pressure phase diagram for the La-doped CaFe{sub 2}As{sub 2} single crystals.

  2. The Influence of Aluminum on the Microstructure and Hardness of Mg-5Si-7Sn Alloy

    Directory of Open Access Journals (Sweden)

    Rzychoń T.

    2016-03-01

    Full Text Available Magnesium alloys due the low density and good mechanical properties are mainly used in the automotive and aerospace industry. In recent years, magnesium alloys are extensively developed for use in high temperatures (above 120°C. Among these alloys, magnesium alloys containing tin and silicon have large possibilities of application due to the formation of thermally stable intermetallic Mg2Sn and Mg2Si. In this paper the influence of aluminum and heat treatment on the on the microstructure and hardness of Mg-7Sn-5Si alloy is reported. It was found that the microstructure of Mg-7Sn-5Si alloy consist of α-Mg solid solution, Mg2Sn and Mg2Si compounds. Addition of 2 wt% of Al to Mg-7Sn-5Si alloy causes the formation of Al2Sn phase. Moreover, Al dissolves in the α-Mg solid solution. The solution heat-treatment of tested alloys at 500°C for 24 h causes the dissolve the Mg2Sn phase in the α-Mg matrix and spheroidization of Mg2Si compound. The Mg2Si primary crystals are stable at solution temperature. After ageing treatment the precipitation process of equilibrium Mg2Sn phase was found in both alloys. The addition of aluminum has a positive effect on the hardness of Mg-7Sn-5Si alloy. In case of Mg-5Si-7Sn-2Al alloy the highest hardness was obtained for sample aged for 148 h at 250°C (88 HV2, while in case of Al-free alloy the highest hardness is 70 HV for material aged for 148 h at 250°C.

  3. Energetic prediction on the stability of A2Mg12Si7, A2Mg4Si3, and AMgSi in the A2Si–Mg2Si system (A = Ca, Sr and Ba) and their calculated electronic structures

    International Nuclear Information System (INIS)

    Imai, Yoji; Mori, Yoshihisa; Nakamura, Shigeyuki; Takarabe, Ken-ichi

    2014-01-01

    Highlights: • Formation energies of A 2 Mg 4 Si 3 , A 2 Mg 12 Si 7 , and AMgSi (A = Ca,Sr,Ba) were calculated. • All AMgSi are quite stable compared to mixture of A 2 Si and Mg 2 Si. • Ba 2 Mg 4 Si 3 and Sr 2 Mg 4 Si 3 are predicted to be stable, but Ca 2 Mg 4 Si 3 is not. • Ca 2 Mg 12 Si 7 and Sr 2 Mg 12 Si 7 are energetically unstable. • Stability of Ba 2 Mg 12 Si 7 is a tender subject. -- Abstract: In order to evaluate the relative stability of A 2 Mg 4 Si 3 , A 2 Mg 12 Si 7 , and AMgSi (A = Ca, Sr, and Ba) in the A 2 Si–Mg 2 Si system, electronic energy changes in the formation of these compounds were calculated using a density-functional theory with the Perdew–Wang generalized gradient approximations. It was found that (1) AMgSi’s are quite stable compared to equi-molar mixture of A 2 Si and Mg 2 Si, (2) Ba 2 Mg 4 Si 3 and Sr 2 Mg 4 Si 3 are also stable, (3) Ca 2 Mg 4 Si 3 and Ca 2 Mg 12 Si 7 are less stable than the mixture of CaMgSi and Mg 2 Si, and (4) Stability of Ba 2 Mg 12 Si 7 is a tender subject and Sr 2 Mg 12 Si 7 is energetically unstable compared to the mixture of Sr 2 Mg 4 Si 3 (or, SrMgSi) and Mg 2 Si. The presence of Sr 2 Mg 12 Si 7 may be due to the vibrational and/or configurational entropy, which are not treated in the present study. From the calculated electronic densities of state, complex compounds of SrMgSi and Mg 2 Si have both p-type and n-type character, depending on the ratio of SrMgSi and Mg 2 Si in that compound

  4. Study of the magnetic disaccommodation in La doped YIG

    International Nuclear Information System (INIS)

    Torres, C.; Hernandez-Gomez, P.; Francisco, C. de; Munoz, J.M.; Alejos, O.; Gonzalez Arias, A.; Perdigao, J.M.; Ferreira, A.R.

    2005-01-01

    The relaxation of the initial magnetic permeability of La doped yttrium iron garnet (YIG) samples with nominal composition Y 3-x La x Fe 5 O 12 (0 2 atmosphere when the La content is at least of 0.3. These results have been interpreted in terms of the formation of a secondary perovskite phase when the La solubility limit is reached. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Radiation Induced Color Centers in a La Doped PWO Crystal

    CERN Document Server

    Deng, Qun

    1998-01-01

    This report presents result of a study on radiation induced color center densities in a La doped lead tungstate ( PWO) crystal. The creation and annihilation constants of radiation induced color centers were determined by using transmittance data measured for a PWO sample before and during Co-60 gamma ray irradiation at a dose rate of 15 rad/hr. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/hr. The result was found to be in a good agreement with experimental data, indicating that this model of color center kinetics can be used to predict behavior of PWO crystals under irradiation.

  6. La doping effect on TZM alloy oxidation behavior

    International Nuclear Information System (INIS)

    Yang, Fan; Wang, Kuai-She; Hu, Ping; He, Huan-Cheng; Kang, Xuan-Qi; Wang, Hua; Liu, Ren-Zhi; Volinsky, Alex A.

    2014-01-01

    Highlights: • The oxidation can be resisted by doping La into TZM alloy. • La doped TZM alloy has more compact organization. • It can rise the starting temperature of severe oxidation reaction by more than 50 °C. • Effectively slow down the oxidation rate. • Provide guidance for experiments of improving high-temperature oxidation resistance. - Abstract: Powder metallurgy methods were utilized to prepare lanthanum-doped (La-TZM) and traditional TZM alloy plates. High temperature oxidation experiments along with the differential thermal analysis were employed to study the oxidation behavior of the two kinds of TZM alloys. An extremely volatile oxide layer was generated on the surface of traditional TZM alloy plates when the oxidation started. Molybdenum oxide volatilization exposed the alloy matrix, which was gradually corroded by oxygen, losing its quality with serious surface degradation. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys has been enhanced, expanding its application range

  7. Effect of La doping on crystalline orientation, microstructure and dielectric properties of PZT thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wencai; Li, Qi; Wang, Xing [Dalian Univ. of Technology, Dalian (China). School of Mechanical Engineering; Yin, Zhifu [Jilin Univ., Changchun (China). Faculty of the School of Mechanical Science and Engineering; Zou, Helin [Dalian Univ. of Technology, Dalian (China). Key Lab. for Micro/Nano Systems and Technology

    2017-11-01

    Lanthanum (La)-modified lead zirconate titanate (PLZT) thin films with doping concentration from 0 to 5 at.-% have been fabricated by sol-gel methods to investigate the effects of La doping on crystalline orientation, microstructure and dielectric properties of the modified films. The characterization of PLZT thin films were performed by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and precision impedance analysis. XRD analysis showed that PLZT films with La doping concentration below 4 at.-% exhibited (100) preferred orientation. SEM results indicated that PLZT films presented dense and columnar microstructures when La doping concentration was less than 3 at.-%, while the others showed columnar microstructures only at the bottom of the cross section. The maximum dielectric constant (1502.59 at 100 Hz) was obtained in a 2 at.-% La-doped film, which increased by 53.9 % compared with undoped film. Without introducing a seed layer, (100) oriented PLZT thin films were prepared by using conventional heat treatment process and adjusting La doping concentration.

  8. Influence of La Doping on Magnetic and Optical Properties of Bismuth Ferrite Nanofibers

    Directory of Open Access Journals (Sweden)

    Ziang Zhang

    2012-01-01

    Full Text Available The influence of La doping on the crystal structure, ferromagnetic, and optical properties of BFO nanofibers was investigated. Bi1−xLaxFeO3 ultrafine nanofibers were synthesized by the electrospinning method. The surface morphology and crystal structure of the as-spun and sintered fibers were not affected by the doping. The impurity phases of the BFO crystals were weakened with the increment of La concentration. The magnetization field curves showed that the magnetization weakened under low La doping proportion, but strengthened with the increase of the doped proportion. The magnetization curves also showed continuous strong enhancement of ferromagnetic behavior. The results of UV-vis and photoabsorption testing revealed little influence of La doping on the optical property.

  9. Thermoluminescence kinetic parameters of different amount La-doped ZnB2O4

    International Nuclear Information System (INIS)

    Kucuk, Nil; Gozel, Aziz Halit; Yüksel, Mehmet; Dogan, Tamer; Topaksu, Mustafa

    2015-01-01

    The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB 2 O 4 phosphors (i.e. ZnB 2 O 4 :0.01La, ZnB 2 O 4 :0.02La, ZnB 2 O 4 :0.03La and ZnB 2 O 4 :0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB 2 O 4 :La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200 °C and a shoulder peak at around 315 °C with a constant heating rate of 5 °C/s. The kinetic parameters of ZnB 2 O 4 :La phosphors TL glow peaks (i.e. order of kinetics (b), activation energies (E a ) and frequency factors (s)) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of E a obtained with these methods for ZnB 2 O 4 :La phosphors are consistent with each other, but the s values differ considerably. - Highlights: • Calculation of TL kinetic parameters for La-doped ZnB 2 O 4 . • La-doped ZnB 2 O 4 was synthesized by nitric acid method. • Well defined main peak at about 200 °C

  10. Surface modification of sol–gel synthesized TiO{sub 2} nanoparticles induced by La-doping

    Energy Technology Data Exchange (ETDEWEB)

    Grujić-Brojčin, M., E-mail: myramyra@ipb.ac.rs [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Armaković, S. [Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg D. Obradovića 3, 21000 Novi Sad (Serbia); Tomić, N. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Abramović, B. [Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg D. Obradovića 3, 21000 Novi Sad (Serbia); Golubović, A.; Stojadinović, B. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Kremenović, A. [Faculty of Mining and Geology, Laboratory for Crystallography, University of Belgrade, Đušina 7, 11000 Belgrade (Serbia); Babić, B. [Institute of Nuclear Sciences “Vinča”, University of Belgrade, 11001 Belgrade (Serbia); Dohčević-Mitrović, Z.; Šćepanović, M. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)

    2014-02-15

    The influence of La-doping in the range of 0.5–6.0 mol% on structural and morphological properties of TiO{sub 2} nanopowders synthesized by sol–gel routine has been investigated by XRPD, AFM, EDS and BET measurements, as well as Raman spectroscopy. The XRPD and Raman measurements have revealed the anatase phase as dominant in all nanopowders, with crystallite size decreasing from ∼ 15 nm in pure TiO{sub 2} to ∼ 12 nm in La-doped samples. The BET data suggest that all samples are fully mesoporous, with mean pore diameters in the range of ∼ 6–8 nm. The specific surface area and the complexity of pore structure are greater in doped samples than in pure TiO{sub 2} sample. The spectroscopic ellipsometry has apparently shown that the band gap has been gradually increased with the increase of La content. The STM and STS techniques have been used successfully to evaluate the surface morphology and electronic properties of La-doped nanopowders. All investigated properties have been related to photocatalytic activity, tested in degradation of a metoprolol tartrate salt (0.05 mM), and induced by UV-radiation. All doped samples showed increased photocatalytic activity compared to pure TiO{sub 2}, among which the 0.65 mol% La-doped sample appeared to be the most efficient. - Highlights: • Effects of La-doping on structural, morphological and electronic properties of TiO{sub 2} nanopowders. • Surface morphology and electronic properties of La-doped nanopowders evaluated by STM/STS. • Spectroscopic ellipsometry shown gradual increase of bandgap with the increase of La content. • Photocatalytic activity of samples was tested in degradation of MET under UV light.

  11. SN Refsdal

    DEFF Research Database (Denmark)

    Kelly, P. L.; Brammer, G.; Selsing, J.

    2016-01-01

    (SNe), and we find strong evidence for a broad H-alpha P-Cygni profile in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show...... in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, SN Refsdal has a blue B-V color and a high luminosity for the assumed range of potential magnifications. If SN Refsdal can be modeled as a scaled version of SN...

  12. Radiation-induced color centers in La-doped PbWO sub 4 crystals

    CERN Document Server

    Deng, Q; Zhu, R Y

    1999-01-01

    This report presents the result of a study on radiation-induced color center densities in La-doped lead tungstate (PbWO sub 4) crystals. The creation and annihilation constants of radiation-induced color centers were determined by using transmittance data measured for a PbWO sub 4 sample before and during sup 6 sup 0 Co gamma-ray irradiation at a dose rate of 15 rad/h. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/h. The result was found to be in good agreement with experimental data, indicating that the behaviour of PbWO sub 4 crystals under irradiation can be predicted according to this model.

  13. Observation of long phase-coherence length in epitaxial La-doped CdO thin films

    Science.gov (United States)

    Yun, Yu; Ma, Yang; Tao, Songsheng; Xing, Wenyu; Chen, Yangyang; Su, Tang; Yuan, Wei; Wei, Jian; Lin, Xi; Niu, Qian; Xie, X. C.; Han, Wei

    2017-12-01

    The search for long electron phase-coherence length, which is the length that an electron can keep its quantum wavelike properties, has attracted considerable interest in the last several decades. Here, we report the long phase-coherence length of ˜3.7 μm in La-doped CdO thin films at 2 K. Systematical investigations of the La doping and the temperature dependences of the electron mobility and the electron phase-coherence length reveal contrasting scattering mechanisms for these two physical properties. Furthermore, these results show that the oxygen vacancies could be the dominant scatters in CdO thin films that break the electron phase coherence, which would shed light on further investigation of phase-coherence properties in oxide materials.

  14. THE STUDY OF HIGH DIELECTRIC CONSTANT MECHANISM OF La-DOPED Ba0.67Sr0.33TiO3 CERAMICS

    Science.gov (United States)

    Xu, Jing; He, Bo; Liu, Han Xing

    It is a common and effective method to enhance the dielectric properties of BST ceramics by adding rare-earth elements. In this paper, it is important to analyze the cause of the high dielectric constant behavior of La-doped BST ceramics. The results show that proper rare earth La dopant (0.2≤x≤0.7) may greatly increase the dielectric constant of BST ceramics, and also improve the temperature stability, evidently. According to the current-voltage (J-V) characteristics, the proper La-doped BST ceramics may reach the better semiconductivity, with the decrease and increase in La doping, the ceramics are insulators. By using the Schottky barrier model and electric microstructure model to find the surface or grain boundary potential barrier height, the width of the depletion layer and grain size do play an important role in impacting the dielectric constant.

  15. Structure and optical band gaps of (Ba,Sr)SnO{sub 3} films grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Timo; Raghavan, Santosh; Ahadi, Kaveh; Kim, Honggyu; Stemmer, Susanne, E-mail: stemmer@mrl.ucsb.edu [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

    2016-09-15

    Epitaxial growth of (Ba{sub x}Sr{sub 1−x})SnO{sub 3} films with 0 ≤ x ≤ 1 using molecular beam epitaxy is reported. It is shown that SrSnO{sub 3} films can be grown coherently strained on closely lattice and symmetry matched PrScO{sub 3} substrates. The evolution of the optical band gap as a function of composition is determined by spectroscopic ellipsometry. The direct band gap monotonously decreases with x from to 4.46 eV (x = 0) to 3.36 eV (x = 1). A large Burnstein-Moss shift is observed with La-doping of BaSnO{sub 3} films. The shift corresponds approximately to the increase in Fermi level and is consistent with the low conduction band mass.

  16. Conflicting results for the deformation properties of forsterite, Mg2SiO4

    International Nuclear Information System (INIS)

    Wal, R.J. van der; Vos, A.; Kirfel, A.

    1987-01-01

    Deformation properties of forsterite have been deduced simultaneously from X-ray diffraction data affected by extinction in Bonn-Pittsburgh (B), and in Groningen (G). For the G crystals, GI and GII, extinction is anisotropic and considerably larger than for crystal B. Measurements were made with Mo radiation for B, and with Mo and Ag radiation for GI and GII. As the Becker and Coppens extinction model is not exact, the deformation properties had to be filtered from the data with refinement models. The flexible B model [α's and populations for single exponential functions (SEF's) refined for l=0-4] and the more rigid G model (SEF's populations refined for l=0-3 and α for l=0; further α's and n's fixed at standard values) yield different results. Refinement of α makes the majority of the SEF's notably diffuse, presumably due to correlation with incorrect extinction corrections. The order of the deformation potentials at the Mg(1) and Mg(2) sites is reversed for B and G. Maxima on the Si-O bonds, which are polarized towards O, are smaller for G (0.20-0.25 e A -3 ) than for B (0.25-0.45 e A -3 ). Although each of the two sets of deformation properties looks acceptable by itself, the present comparison shows that neither of them may be sufficiently close to the truth. The diffraction data are available on request from the Electron Density Data Bank (Professor H. Burzlaff, Institut fuer Angewandte Physik, Bismarckstrasse 10, D-8520 Erlangen, Federal Republic of Germany). Details of the measurements are described in the paper. (orig.)

  17. Influence of Al grain boundaries segregations and La-doping on embrittlement of intermetallic NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, Anatoly I., E-mail: a_kovalev@sprg.ru; Wainstein, Dmitry L.; Rashkovskiy, Alexander Yu.

    2015-11-01

    Highlights: • We investigated Al grain boundaries segregations in ordered pure and La-doped NiAl. • Structural segregation of Al decreases critical strain for brittle cracks nucleation. • La alloying sharply improves plasticity of NiAl intermetallic. • Metallicity of interatomic bonds on grain boundaries increases at La alloying. • We have experimentally measured by EELFS that La atoms are located in Al sublattice. - Abstract: The microscopic nature of intergranular fracture of NiAl was experimentally investigated by the set of electron spectroscopy techniques. The paper demonstrates that embrittlement of NiAl intermetallic compound is caused by ordering of atomic structure that leads to formation of structural aluminum segregations at grain boundaries (GB). Such segregations contain high number of brittle covalent interatomic bonds. The alloying by La increases the ductility of material avoiding Al GB enrichment and disordering GB atomic structure. The influence of La alloying on NiAl mechanical properties was investigated. GB chemical composition, atomic and electronic structure transformations after La doping were investigated by AES, XPS and EELFS techniques. To qualify the interatomic bonds metallicity the Fermi level (E{sub F}) position and electrons density (n{sub eff}) in conduction band were determined in both undoped and doped NiAl. Basing on experimental results the physical model of GB brittleness formation was proposed.

  18. Photocatalytic degradation of commercial phoxim over La-doped TiO2 nanoparticles in aqueous suspension.

    Science.gov (United States)

    Dai, Ke; Peng, Tianyou; Chen, Hao; Liu, Juan; Zan, Lin

    2009-03-01

    Photocatalytic degradation of commercial phoxim emulsion in aqueous suspension was investigated by using La-doped mesoporous TiO2 nanoparticles (m-TiO2) as the photocatalyst under UV irradiation. Effects of La-doping level, calcination temperature, and additional amount of the photocatalyst on the photocatalytic degradation efficiency were investigated in detail. Experimental results indicate that 20 mg L(-1) phoxim in 0.5 g L(-1) La/m-TiO2 suspension (the initial pH 4.43) can be decomposed as prolonging the irradiation time. Almost 100% phoxim was decomposed after 4 h irradiation according to the spectrophotometric analyses, whereas the mineralization rate of phoxim just reached ca. 80% as checked by ion chromatography (IC) analyses. The elimination of the organic solvent in the phoxim emulsion as well as the formation and decomposition of some degradation intermediates were observed by high-performance liquid chromatography-mass spectroscopy (HPLC-MS). On the basis of the analysis results on the photocatalytic degradation intermediates, two possible photocatalytic degradation pathways are proposed under the present experimental conditions, which reveal that both the hydrolysis and adsorption of phoxim under UV light irradiation play important roles during the photocatalytic degradation of phoxim.

  19. Structural characteristics and UV-light enhanced gas sensitivity of La-doped ZnO nanoparticles

    International Nuclear Information System (INIS)

    Ge Chunqiao; Xie Changsheng; Hu Mulin; Gui Yanghai; Bai Zikui; Zeng Dawen

    2007-01-01

    La-doped ZnO nanoparticles were synthesized by sol-gel method starting from zinc acetate dihydrate, lanthanum sesquioxide, alcohol and nitric acid. The crystal structure and morphology of the nanoparticles were characterized by XRD, FESEM, respectively. The thermal decomposition behavior of the the ZnO-based xerogel was detected by TG-DSC. The results show that as-prepared nanoparticles with the hexagonal wurtzite contain the adsorbed water and some organic compounds below 300 o C, which is the key to the calcinations of the ZnO-based xerogel. Pure ZnO and La-doped ZnO thick film sensors were prepared and tested for specific sensitivity to alcohol and benzene with (and without) UV-light excitation. Among all, 10 at.%La-ZnO-based sensors are significantly sensitive to 100 ppm alcohol and 100 ppm benzene. There is an obvious enhancement of the gas-sensing performances with UV-light excitation. That is, the sensitivity to 100 ppm benzene rises twice. The observed sensitivity to alcohol and benzene could be explained with the surface adsorption theory and the conduction-band theory

  20. Crystal structure, dielectric, ferroelectric and energy storage properties of La-doped BaTiO3 semiconducting ceramics

    Directory of Open Access Journals (Sweden)

    Venkata Sreenivas Puli

    2015-09-01

    Full Text Available Polycrystalline La-doped BaTiO3 (Ba(1-xLax\tTiO3 [x=0,0.0005,0.001,0.003] ceramics (denoted as BTO,BLT1,BLT2,BLT3 were synthesized by conventional solid-state reaction method and characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and Raman spectroscopy. XRD and Raman spectra revealed single-phase tetragonal perovskite crystalline structure. Well-saturated polarization–electric field (P–E hysteresis loops were observed with the measurement frequency of 50 Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350 J/cm3 with energy efficiency (n∼9%, which is useful in energy storage capacitor applications. Dielectric studies revealed anomalies around 415–420 K and near the Curie temperature. The latter is attributed to the ferroelectric to paraelectric phase transition. Better dielectric performances were obtained for La-doped samples sintered at 1350°C for 4 h. Grain growth is inhibited with lanthanum (La incorporation into the BTO lattice. Room temperature semiconducting behavior with positive temperature coefficient of resistivity (PTCR behavior at TC is attributed to electron compensation mechanism.

  1. La Doping of CdS for Enhanced CdS/CdSe Quantum Dot Cosensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Xiaolei Qi

    2015-01-01

    Full Text Available CdS/CdSe system of quantum dot cosensitized solar cells (QDCSCs is one of the most attractive structures for high-efficiency due to its effect of level adjusting. However, the stepwise structure formed between levels of CdS and CdSe has a limitation for enhancing the efficiencies. Metal ions doping in quantum dots have emerged as a common way for changing the Fermi level, band gap, and conductance. Here we report an innovative concept for the rare earth materials La-doped of the CdS layer in the CdS/CdSe QDCSCs by means of the successive ionic layer adsorption and reaction (SILAR. Then we tested that La doped quantum dots can help more electrons accumulate in CdS film, which makes the Fermi level shift up and form a stepped structure. This method leads to enhanced absorption intensity, obviously increasing current density in CdS/CdSe QDCSCs. Our research is a new exploration for improving efficiencies of quantum dot sensitized solar cells.

  2. La-doped Al2O3 supported Au nanoparticles: highly active and selective catalysts for PROX under PEMFC operation conditions.

    Science.gov (United States)

    Lin, Qingquan; Qiao, Botao; Huang, Yanqiang; Li, Lin; Lin, Jian; Liu, Xiao Yan; Wang, Aiqin; Li, Wen-Cui; Zhang, Tao

    2014-03-14

    La-doped γ-Al2O3 supported Au catalysts show high activity and selectivity for the PROX reaction under PEMFC operation conditions. The superior performance is attributed to the formation of LaAlO3, which suppresses H2 oxidation and strengthens CO adsorption on Au sites, thereby improving competitive oxidation of CO at elevated temperature.

  3. Influence of Al grain boundaries segregations and La-doping on embrittlement of intermetallic NiAl

    Science.gov (United States)

    Kovalev, Anatoly I.; Wainstein, Dmitry L.; Rashkovskiy, Alexander Yu.

    2015-11-01

    The microscopic nature of intergranular fracture of NiAl was experimentally investigated by the set of electron spectroscopy techniques. The paper demonstrates that embrittlement of NiAl intermetallic compound is caused by ordering of atomic structure that leads to formation of structural aluminum segregations at grain boundaries (GB). Such segregations contain high number of brittle covalent interatomic bonds. The alloying by La increases the ductility of material avoiding Al GB enrichment and disordering GB atomic structure. The influence of La alloying on NiAl mechanical properties was investigated. GB chemical composition, atomic and electronic structure transformations after La doping were investigated by AES, XPS and EELFS techniques. To qualify the interatomic bonds metallicity the Fermi level (EF) position and electrons density (neff) in conduction band were determined in both undoped and doped NiAl. Basing on experimental results the physical model of GB brittleness formation was proposed.

  4. Application of La-Doped SrTiO3 in Advanced Metal-Supported Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sabrina Presto

    2018-03-01

    Full Text Available Composite materials frequently allow the drawbacks of single components to be overcome thanks to a synergistic combination of material- and structure-specific features, leading to enhanced and also new properties. This is the case of a metallic-ceramic composite, a nickel-chromium-aluminum (NiCrAl foam impregnated with La-doped Strontium Titanate (LST. This particular cermet has very interesting properties that can be used in different fields of application, namely: mechanical robustness provided by the metal foam; and chemical stability in harsh conditions of temperature and atmosphere by promotion of a thin protective layer of alumina (Al2O3; high electronic conductivity given by a percolating ceramic conducting phase, i.e., La-doped Strontium Titanate. In this paper, its application as a current collector in a metal-supported Solid Oxide Fuel Cells (SOFC was studied. Firstly, the electronic properties of different compositions, stoichiometric and under stoichiometric, of LST were analyzed to choose the best one in terms of conductivity and phase purity. Then, LST chemical stability was studied in the presence of Al2O3 at different temperatures, gas compositions and aging times. Finally, stability and conductivity of LST-impregnated NiCrAl foam composite materials were measured, and LST was found to be fully compatible with the NiCrAl foam, as no reactions were detected in oxidizing and reducing atmosphere after up to 300 h operation at 750 °C and 900 °C between the Al2O3 layer and LST. Results showed that the composite is suitable as a current collector in innovative designs of metal-supported SOFC, like the Evolve cell, in which the metallic part is supposed not only to provide the structural stability to the cell, but also to play the role of current collector due to the impregnation of ceramic material.

  5. Preparation of Pd-loaded La-doped TiO{sub 2} nanotubes and investigation of their photocatalytic activity under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Zong, Lanlan; Li, Qiuye, E-mail: qiuyeli@henu.edu.cn; Zhang, Jiwei; Wang, Xiaodong; Yang, Jianjun [Henan University, Key Laboratory for Special Functional Materials (China)

    2013-11-15

    Orthorhombic titanic acid nanotubes (TAN) have large BET surface area and small-diameter one-dimensional nanotubular morphology, so they can work as a good supporter and a precursor of TiO{sub 2}. However, in our former research, we found that calcination of TAN to anatase TiO{sub 2} would destroy the nanotubular structure and decrease the BET surface area sharply. In this work, we utilized the pillar effect of the foreign nanoparticles (La{sub 2}O{sub 3}) to keep the nanotubular morphology of TiO{sub 2}, and obtained the anatase TiO{sub 2} nanotubes with large BET surface area. For improving the photocatalytic activity, Pd nanoparticles were loaded as the electron traps on the surface of La-doped TiO{sub 2} by photo-deposition method. The photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, diffuse reflectance spectra, and N{sub 2} adsorption–desorption isotherms measurement. Their photocatalytic activities were evaluated by the removal of propylene under visible light irradiation (λ ≥ 420 nm). The results showed that the photocatalytic activity of Pd-loaded La-doped TiO{sub 2} nanotubes improved effectively compared with that of La-doped TiO{sub 2} and pure TiO{sub 2}.

  6. Dopant-site-dependent scattering by dislocations in epitaxial films of perovskite semiconductor BaSnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Useong; Park, Chulkwon; Kim, Rokyeon; Mun, Hyo Sik; Kim, Hoon Min; Kim, Namwook; Yu, Jaejun; Char, Kookrin, E-mail: kchar@phya.snu.ac.kr [Center for Strongly Correlated Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Ha, Taewoo; Kim, Jae Hoon [Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Hyung Joon; Kim, Tai Hoon; Kim, Kee Hoon [Center for Novel States of Complex Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2014-05-01

    We studied the conduction mechanism in Sb-doped BaSnO{sub 3} epitaxial films, and compared its behavior with that of the mechanism of its counterpart, La-doped BaSnO{sub 3}. We found that the electron mobility in BaSnO{sub 3} films was reduced by almost 7 times when the dopant was changed from La to Sb, despite little change in the effective mass of the carriers. This indicates that the scattering rate of conduction electrons in the BaSnO{sub 3} system is strongly affected by the site at which the dopants are located. More importantly, we found that electron scattering by threading dislocations also depends critically on the dopant site. We propose that the large enhancement of scattering by the threading dislocations in Sb-doped BaSnO{sub 3} films is caused by the combination effect of the change in the distribution of Sb impurities in the films, the formation of the Sb impurity clusters near the threading dislocations, and the conduction electron clustering near the Sb impurities.

  7. Dopant-site-dependent scattering by dislocations in epitaxial films of perovskite semiconductor BaSnO3

    Directory of Open Access Journals (Sweden)

    Useong Kim

    2014-05-01

    Full Text Available We studied the conduction mechanism in Sb-doped BaSnO3 epitaxial films, and compared its behavior with that of the mechanism of its counterpart, La-doped BaSnO3. We found that the electron mobility in BaSnO3 films was reduced by almost 7 times when the dopant was changed from La to Sb, despite little change in the effective mass of the carriers. This indicates that the scattering rate of conduction electrons in the BaSnO3 system is strongly affected by the site at which the dopants are located. More importantly, we found that electron scattering by threading dislocations also depends critically on the dopant site. We propose that the large enhancement of scattering by the threading dislocations in Sb-doped BaSnO3 films is caused by the combination effect of the change in the distribution of Sb impurities in the films, the formation of the Sb impurity clusters near the threading dislocations, and the conduction electron clustering near the Sb impurities.

  8. Influence of La doping on structural and dielectric properties of SrBi2Nb2O9 ceramics

    International Nuclear Information System (INIS)

    Verma, Maya; Sreenivas, K.; Gupta, Vinay

    2009-01-01

    Lanthanum doped SrBi 2 Nb 2 O 9 ceramics with the chemical formula SrBi 2-x La x Nb 2 O 9 (SBLN) (x=0-0.5) have been prepared through conventional solid state route. X-ray diffraction reveals the shrinkage of unit cell of strontium bismuth niobate with incorporation of La 3+ dopant, having no lone pair electrons. Shifting of Raman phonon modes indicates the reduced rattling space of NbO 6 octahedra with increase in La doping concentration. Further, the softening of lowest frequency phonon mode with increasing x in SBLN shows the transition from ferroelectric to paraelectric at room temperature. The dielectric properties for all the compositions are studied as a function of temperature (25 to 500 deg. C) over the frequency range of 10 kHz-1 MHz. With increase in lanthanum doping concentration the phase transition becomes diffused and transition temperature gets shifted toward lower temperature. A phase transition from normal ferroelectric to paraelectric has been observed via relaxor-type ferroelectrics with increase in x. The frequency dependence of transition temperature was studied in terms of Vogel-Fulcher relation for SBLN (x=0.4)

  9. Evaluation of La-Doped Mesoporous Bioactive Glass as Adsorbent and Photocatalyst for Removal of Methylene Blue from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Liying Li

    2015-01-01

    Full Text Available A series of La-doped mesoporous bioactive glass (BG-La materials with excellent biosafety and hypotoxicity have been prepared and tested as adsorbent. The study was aimed to evaluate the possibility of utilizing BG-La for the adsorptive removal of methylene blue (MB from aqueous solution and test the adsorption and desorption behavior of this new material. The process parameters affecting adsorption behaviors such as pH, contact time, and initial concentration and the photocatalytic degradation of MB were systematically investigated. The result showed that BG-La had excellent removal rate (R of MB, and BG-La showed better photocatalytic effect than undoped mesoporous bioactive glass (BG. Furthermore, the MB loaded BG-La was easily desorbed with acid solution due to its electronegativity and mesoporous structure. The result indicated that these materials can be employed as candidates for removal of dye pollutant owing to their high removal rate, excellent photocatalytic effect, desorption performance, and their reusability.

  10. Influence of La doping on structural and dielectric properties of SrBi2Nb2O9 ceramics

    Science.gov (United States)

    Verma, Maya; Sreenivas, K.; Gupta, Vinay

    2009-01-01

    Lanthanum doped SrBi2Nb2O9 ceramics with the chemical formula SrBi2-xLaxNb2O9 (SBLN) (x =0-0.5) have been prepared through conventional solid state route. X-ray diffraction reveals the shrinkage of unit cell of strontium bismuth niobate with incorporation of La3+ dopant, having no lone pair electrons. Shifting of Raman phonon modes indicates the reduced rattling space of NbO6 octahedra with increase in La doping concentration. Further, the softening of lowest frequency phonon mode with increasing x in SBLN shows the transition from ferroelectric to paraelectric at room temperature. The dielectric properties for all the compositions are studied as a function of temperature (25 to 500 °C) over the frequency range of 10 kHz-1 MHz. With increase in lanthanum doping concentration the phase transition becomes diffused and transition temperature gets shifted toward lower temperature. A phase transition from normal ferroelectric to paraelectric has been observed via relaxor-type ferroelectrics with increase in x. The frequency dependence of transition temperature was studied in terms of Vogel-Fulcher relation for SBLN (x =0.4).

  11. Effect of La doping on the ferroic order in Pb-based perovskite-type relaxor ferroelectrics

    Science.gov (United States)

    Maier, B. J.; Welsch, A.-M.; Mihailova, B.; Angel, R. J.; Zhao, J.; Paulmann, C.; Engel, J. M.; Marshall, W. G.; Gospodinov, M.; Petrova, D.; Bismayer, U.

    2011-04-01

    The structural alteration induced by the substitution of three-valent cations with an isotropic electronic outermost shell for Pb2+ in perovskite-type relaxors was investigated in the solid solutions Pb1-xLaxSc(1+x)/2Ta(1-x)/2O3, x =0.08 (PST-La) and Pb1-xLaxSc(1+x)/2Nb(1-x)/2O3, x =0.23 (PSN-La). In order to distinguish the “charge” effects from “strain” effects associated with the incorporation of La3+ in the structure, Sr-containing PbSc0.5Nb0.5O3 was characterized as well. The structure of the compounds was analyzed by in situ Raman spectroscopy, single-crystal x-ray diffraction, and powder neutron diffraction at different temperatures or pressures. It is shown that the embedding of La3+ strongly affects the ferroic structural species due to strain effects through a disturbance of the system of lone-pair electrons associated with Pb2+ and a decrease in the tolerance factor. La doping suppresses the dynamical coupling between off-centered Pb and B-site cations and enhances antiphase BO6 octahedral tilting which, depending on the level of doping, may lead to long-range order of antiphase BO6 tilts at ambient conditions and frustrated antiferroelectric order of Pb ions at low temperatures.

  12. Crystalline and Electronic Structures and Magnetic and Electrical Properties of La-Doped Ca2Fe2O5 Compounds

    Science.gov (United States)

    Phan, T. L.; Tho, P. T.; Tran, N.; Kim, D. H.; Lee, B. W.; Yang, D. S.; Thiet, D. V.; Cho, S. L.

    2018-01-01

    Brownmillerite Ca2Fe2O5 has been observed to exhibit many outstanding properties that are applicable to ecotechnology. However, very little work on doped Ca2Fe2O5 compounds has been carried out to widen their application scope. We present herein a detailed study of the crystalline/geometric and electronic structures and magnetic and electrical properties of Ca2- x La x Fe2O5 ( x = 0 to 1) prepared by conventional solid-state reaction. X-ray diffraction patterns indicated that the compounds with x = 0 to 0.05 exhibited brownmillerite-type single phase. La doping with higher content ( x ≥ 0.1) stimulated additive formation of Grenier- (LaCa2Fe3O8) and perovskite-type (LaFeO3) phases. Extended x-ray absorption fine structure spectroscopy at the Fe K-edge and electron spin resonance spectroscopy revealed presence of Fe3+ in the parent Ca2Fe2O5 ( x = 0) and both Fe3+ and Fe4+ in the doped compounds ( x ≥ 0.05). The Fe4+ content tended to increase with increasing x. This stimulates ferromagnetic exchange interactions between Fe3+ and Fe4+ ions and directly influences the magnetic properties of Ca2- x La x Fe2O5. Electrical resistivity ( ρ) measurements in the temperature range of T = 20 K to 400 K revealed that all the compounds exhibit insulator behavior; the ρ( T) data for x ≥ 0.1 could be described based on the adiabatic small polaron hopping model.

  13. Competing exchange bias and field-induced ferromagnetism in La-doped BaFe O3

    Science.gov (United States)

    Fita, I.; Wisniewski, A.; Puzniak, R.; Iwanowski, P.; Markovich, V.; Kolesnik, S.; Dabrowski, B.

    2017-04-01

    An exchange bias (EB) effect was observed in mixed valent L axB a1 -xFe O3 (x =0.125 , 0.25, 0.33) perovskites exhibiting the antiferromagnetic (AFM) helical order among F e4 + ions coexisting with the ferromagnetic (FM) cluster phase in the ground state. The L a3 + ions for B a2 + site substitution, associated with increase in number of the AFM coupled F e3 + - F e4 + pairs as well as some F e3 + - F e3 + pairs, leads to strengthening of the AFM phase and consequently to the alteration of the EB characteristics, which depend on level of the La doping x . At low doping x ≤0.25 , an abnormal dependence of the EB field, HEB, on the cooling field, Hcool, was found. The HEB increases rapidly with increasing cooling field at low Hcool, but it falls suddenly at cooling fields higher than 20 kOe, reducing by an order of magnitude at 90 kOe. The suppression of EB is caused by the field-induced increased volume of the FM phase, due to the transformation of the AFM helical spin structure into the FM one. Thus, low-doped L axB a1 -xFe O3 demonstrates a competition of two alternate cooling-field-induced effects, one of which leads to the EB anisotropy and another one to the enhanced ferromagnetism. In contrast, the x =0.33 sample, having a strong AFM constituent, shows no field-induced FM and no drop in the EB field. Accordingly, the HEB vs Hcool dependence was found to be well explained in the framework of a model describing phase-separated AFM-FM systems, namely, the model assuming isolated FM clusters of size ˜4 nm embedded in the AFM matrix.

  14. Growth and physical properties of highly oriented La-doped (K,Na)NbO3 ferroelectric thin films

    International Nuclear Information System (INIS)

    Vendrell, X.; Raymond, O.; Ochoa, D.A.; García, J.E.; Mestres, L.

    2015-01-01

    Lead-free (K,Na)NbO 3 (KNN) and La doped (K,Na)NbO 3 (KNN-La) thin films are grown on SrTiO 3 substrates using the chemical solution deposition method. The effect of adding different amounts of Na and K excess (0–20 mol%) is investigated. The results confirm the necessity of adding 20 mol% excess amounts of Na and K precursor solutions in order to avoid the formation of the secondary phase, K 4 Nb 6 O 17 , as confirmed by X-ray diffraction and Raman spectroscopy. Moreover, when adding a 20 mol% of alkaline metal excess, the thin films are highly textured with out-of-plane preferential orientation in the [100] direction of the [100] orientation of the substrate. Doping with lanthanum results in a decrease of the leakage current density at low electric field, and an increase in the dielectric permittivity across the whole temperature range (80–380 K). Although the (100)-oriented KNN and KNN-La films exhibited rounded hysteresis loops, at low temperatures the films show the typical ferroelectric hysteresis loops. - Highlights: • (K 0.5 Na 0.5 )NbO 3 and [(K 0.5 Na 0.5 ) 0.985 La 0.005 ]NbO 3 thin films have been prepared. • The obtained thin films show an excellent (100) preferred orientation. • Doping with lanthanum results in a decrease of the leakage current density. • The dielectric properties are enhanced when doping with lanthanum

  15. Study on mechanism of photocatalytic performance of La-doped TiO2/Ti photoelectrodes by theoretical and experimental methods

    International Nuclear Information System (INIS)

    Xin Yanjun; Liu Huiling

    2011-01-01

    TiO 2 photoelectrodes with various nanostructures have been successfully prepared by the anodization method. The morphology, microstructure and optical properties of as-prepared photoelectrodes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet/visible light diffuse reflectance spectra (UV/vis/DRS), surface photovoltage spectroscopy (SPS) and photocurrent. The electronic structure and optical properties of La doped/undoped TiO 2 photoelectrodes with different crystal structures were calculated by the density function theory. The photocatalytic and photoelectrocatalytic activities of as-prepared photoelectrodes were evaluated. The results showed that the anodization potentials played a crucial role in the surface morphology and microstructure. Both results of theoretical calculations and experimental tests demonstrated that La-doped photoelectrodes were more sensitive to light than undoped one. The difference of photoelectrodes performance was ascribed to the crystal configuration, impurity energy levels and long-range orientation moving of photogenerated carriers. - Graphical abstract: Photophysical chemistry processes in as-prepared TiO 2 photoelectrodes. Overall scheme of TiO 2 photoelectrodes: (A) movement of photoelectrons and holes without bias potentials; (B) movement of photoelectrons and holes at applied bias potentials; (a) and (b) were the transmission of photogenerated electrons and holes of local enlargement of (A) (black open circle): (a) photoelectrons movement in P-TiO 2 photoelectrodes and La-TiO 2 photoelectrodes, the red dot line denotes the top of valence band (VB) and the bottom of conduction band (CB) of pure photoelectrodes; (b) photoelectrons movement in P-160 and La-160 TiO 2 photoelectrodes (mixed crystal phase). The number refers to as follows: (1) transmission process of photoelectrons and holes; (2) recombination process of photoelectrons and holes. Arrows represent the moving direction of

  16. Band gap and mobility of epitaxial perovskite BaSn1 -xHfxO3 thin films

    Science.gov (United States)

    Shin, Juyeon; Lim, Jinyoung; Ha, Taewoo; Kim, Young Mo; Park, Chulkwon; Yu, Jaejun; Kim, Jae Hoon; Char, Kookrin

    2018-02-01

    A wide band-gap perovskite oxide BaSn O3 is attracting much attention due to its high electron mobility and oxygen stability. On the other hand, BaHf O3 was recently reported to be an effective high-k gate oxide. Here, we investigate the band gap and mobility of solid solutions of BaS n1 -xH fxO3 (x =0 -1 ) (BSHO) as a basis to build advanced perovskite oxide heterostructures. All the films were epitaxially grown on MgO substrates using pulsed laser deposition. Density functional theory calculations confirmed that Hf substitution does not create midgap states while increasing the band gap. From x-ray diffraction and optical transmittance measurements, the lattice constants and the band-gap values are significantly modified by Hf substitution. We also measured the transport properties of n -type La-doped BSHO films [(Ba ,La ) (Sn ,Hf ) O3 ] , investigating the feasibility of modulation doping in the BaSn O3/BSHO heterostructures. The Hall measurement data revealed that, as the Hf content increases, the activation rate of the La dopant decreases and the scattering rate of the electrons sharply increases. These properties of BSHO films may be useful for applications in various heterostructures based on the BaSn O3 system.

  17. Rapid Synthesis and Formation Mechanism of Core-Shell-Structured La-Doped SrTiO3 with a Nb-Doped Shell

    Directory of Open Access Journals (Sweden)

    Nam-Hee Park

    2015-07-01

    Full Text Available To provide a convenient and practical synthesis process for metal ion doping on the surface of nanoparticles in an assembled nanostructure, core-shell-structured La-doped SrTiO3 nanocubes with a Nb-doped surface layer were synthesized via a rapid synthesis combining a rapid sol-precipitation and hydrothermal process. The La-doped SrTiO3 nanocubes were formed at room temperature by a rapid dissolution of NaOH pellets during the rapid sol-precipitation process, and the Nb-doped surface (shell along with Nb-rich edges formed on the core nanocubes via the hydrothermal process. The formation mechanism of the core-shell-structured nanocubes and their shape evolution as a function of the Nb doping level were investigated. The synthesized core-shell-structured nanocubes could be arranged face-to-face on a SiO2/Si substrate by a slow evaporation process, and this nanostructured 10 μm thick thin film showed a smooth surface.

  18. Synthesis of La2O3 doped Zn2SnO4 hollow fibers by electrospinning method and application in detecting of acetone

    Science.gov (United States)

    Yang, H. M.; Ma, S. Y.; Yang, G. J.; Chen, Q.; Zeng, Q. Z.; Ge, Q.; Ma, L.; Tie, Y.

    2017-12-01

    Hollow porous pure and La2O3 doped Zn2SnO4 fibers were synthesized via single capillary electrospinning technology and used for obtaining of gas sensors. The as-prepared samples were characterized by microscopy, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy and UV-vis absorption spectra. The newly obtained gas sensors were investigated for acetone detection. Compared with pure Zn2SnO4 hollow fibers, the La2O3 doped Zn2SnO4 hollow fibers not only exhibited perfect sensing performance toward acetone with excellent selectivity, high response and fast response/recovery capability (7 s for adsorption and 9 s for desorption), but also the operating temperature was reduced from 240 °C to 200 °C. These results demonstrated that the special hollow porous La doped Zn2SnO4 fibers structures were used as the sensing material for fabricating high performance acetone sensors. The acetone sensing mechanism of La2O3 doped Zn2SnO4 hollow fibers was discussed too.

  19. Solid phase epitaxial growth of high mobility La:BaSnO_3 thin films co-doped with interstitial hydrogen

    International Nuclear Information System (INIS)

    Niedermeier, Christian A.; Rhode, Sneha; Fearn, Sarah; Moram, Michelle A.; Ide, Keisuke; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio

    2016-01-01

    This work presents the solid phase epitaxial growth of high mobility La:BaSnO_3 thin films on SrTiO_3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO_3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm"2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO_3 thin films, and a 9%–16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO_3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO_3 thin films were increased to 3 × 10"1"9" cm"−"3 and in La:BaSnO_3 thin films from 6 × 10"1"9" cm"−"3 to 1.5 × 10"2"0" cm"−"3, supporting a theoretical prediction that interstitial H serves as an excellent n-type dopant. An analysis of the free electron absorption by infrared spectroscopy yields a small (H,La):BaSnO_3 electron effective mass of 0.27 ± 0.05 m_0 and an optical mobility of 26 ± 7 cm"2/Vs. As compared to La:BaSnO_3 single crystals, the smaller electron mobility in epitaxial thin films grown on SrTiO_3 substrates is ascribed to threading dislocations as observed in high resolution transmission electron micrographs.

  20. Whisker and Hillock formation on Sn, Sn-Cu and Sn-Pb electrodeposits

    International Nuclear Information System (INIS)

    Boettinger, W.J.; Johnson, C.E.; Bendersky, L.A.; Moon, K.-W.; Williams, M.E.; Stafford, G.R.

    2005-01-01

    High purity bright Sn, Sn-Cu and Sn-Pb layers, 3, 7 and 16 μm thick were electrodeposited on phosphor bronze cantilever beams in a rotating disk apparatus. Beam deflection measurements within 15 min of plating proved that all electrodeposits had in-plane compressive stress. In several days, the surfaces of the Sn-Cu deposits, which have the highest compressive stress, develop 50 μm contorted hillocks and 200 μm whiskers, pure Sn deposits develop 20 μm compact conical hillocks, and Sn-Pb deposits, which have the lowest compressive stress, remain unchanged. The differences between the initial compressive stresses for each alloy and pure Sn is due to the rapid precipitation of Cu 6 Sn 5 or Pb particles, respectively, within supersaturated Sn grains produced by electrodeposition. Over longer time, analysis of beam deflection measurements indicates that the compressive stress is augmented by the formation of Cu 6 Sn 5 on the bronze/Sn interface, while creep of the electrodeposit tends to decrease the compressive stress. Uniform creep occurs for Sn-Pb because it has an equi-axed grain structure. Localized creep in the form of hillocks and whiskers occurs for Sn and Sn-Cu because both have columnar structures. Compact hillocks form for the Sn deposits because the columnar grain boundaries are mobile. Contorted hillocks and whiskers form for the Sn-Cu deposits because the columnar grain boundary motion is impeded

  1. Mobility Optimization in LaxBa1-xSnO3 Thin Films Deposited via High Pressure Oxygen Sputtering

    Science.gov (United States)

    Postiglione, William Michael

    BaSnO3 (BSO) is one of the most promising semiconducting oxides currently being explored for use in future electronic applications. BSO possesses a unique combination of high room temperature mobility (even at very high carrier concentrations, > 1019 cm-3), wide band gap, and high temperature stability, making it a potentially useful material for myriad applications. Significant challenges remain however in optimizing the properties and processing of epitaxial BSO, a critical step towards industrial applications. In this study we investigate the viability of using high pressure oxygen sputtering to produce high mobility La-doped BSO thin films. In the first part of our investigation we synthesized, using solid state reaction, phase-pure stoichiometric polycrystalline 2% La-doped BaSnO 3 for use as a target material in our sputtering system. We verified the experimental bulk lattice constant, 4.117 A, to be in good agreement with literature values. Next, we set out to optimize the growth conditions for DC sputtering of La doped BaSnO3. We found that mobility for all our films increased monotonically with deposition temperature, suggesting the optimum temperature for deposition is > 900 °C and implicating a likely improvement in transport properties with post-growth thermal anneal. We then preformed systematic studies aimed at probing the effects of varying thickness and deposition rate to optimize the structural and electronic transport properties in unbuffered BSO films. In this report we demonstrate the ability to grow 2% La BSO thin films with an effective dopant activation of essentially 100%. Our films showed fully relaxed (bulk), out-of-plane lattice parameter values when deposited on LaAlO3, MgO, and (LaAlO3)0.3(Sr2 TaAlO6)0.7 substrates, and slightly expanded out-of-plane lattice parameters for films deposited on SrTiO3, GdScO3, and PrScO3 substrates. The surface roughness's of our films were measured via AFM, and determined to be on the nm scale or better

  2. The normal state resistivity of CaTh- and La-doped Y(Nd-123 superconductors in the bipolaron model

    Directory of Open Access Journals (Sweden)

    S. Ghorbani

    2007-12-01

    Full Text Available Polycrystalline samples of Y1-2xCaxThxBa2Cu3O7-δ (with 0.00 ≤x ≤ 0.075 and NdBa2-xLaxCu3O7-δ (with 0.0≤x≤ 0.30 were prepared by the standard solid state method. The transport and superconducting properties have been studied by the resistivity measurements as a function of temperature and doping concentration. Data of resistivity as a function of temperature was analyzed in terms of the bipolaran model. The model well described resistivity data up to near the critical temperature. Obtained results suggested that the hole localization is the main reason for superconducting suppression in the charge neutral doped cuprates and the La doped Nd-123 in addition charge filling.

  3. SN 2009E

    DEFF Research Database (Denmark)

    Pastorello...[], A.; Pumo, M.L.; Navasardyan, H.

    2012-01-01

    . In this paper we investigate the properties of SN 2009E, which exploded in a relatively nearby spiral galaxy (NGC 4141) and that is probably the faintest 1987A-like supernova discovered so far. We also attempt to characterize this subgroup of core-collapse supernovae with the help of the literature and present...... observations which started about 2 months after the supernova explosion, highlight significant differences between SN 2009E and the prototypical SN 1987A. Modelling the data of SN 2009E allows us to constrain the explosion parameters and the properties of the progenitor star, and compare the inferred estimates...... 2009E ejected about 0.04 M⊙ of 56Ni, which is the smallest 56Ni mass in our sample of 1987A-like events. Modelling the observations with a radiation hydrodynamics code, we infer for SN 2009E a kinetic plus thermal energy of about 0.6 foe, an initial radius of ~7 × 1012 cm and an ejected mass of ~19 M...

  4. SN 2012fr

    DEFF Research Database (Denmark)

    Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.

    2018-01-01

    We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epo...

  5. Comparison of the electrochemical performance of mesoscopic Cu2Sb, SnSb and Sn/SnSb alloy powders

    International Nuclear Information System (INIS)

    Zhang Ge; Huang Kelong; Liu Suqin; Zhang Wei; Gong Benli

    2006-01-01

    Cu 2 Sb, SnSb and Sn/SnSb mesoscopic alloy powders were prepared by chemical reduction, respectively. The crystal structures and particle morphology of Cu 2 Sb, SnSb and Sn/SnSb were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performances of the Cu 2 Sb, SnSb and Sn/SnSb electrodes were investigated by galvanostatic charge and discharge cycling and electrochemical impedance spectroscopy (EIS). The results showed the first charge and discharge capacities of SnSb and Sn/SnSb were higher than Cu 2 Sb, but after 15 cycles, the charge capacity fading rates of Cu 2 Sb, Sn/SnSb and Sn/SnSb were 26.16%, 55.33% and 47.39%, respectively. Cu 2 Sb had a better cycle performance, and Sn/SnSb multiphase alloy was prior to pure SnSb due to the existence of excessive Sn in Sn/SnSb system

  6. Study of neutron-deficient Sn isotopes

    International Nuclear Information System (INIS)

    Auger, G.

    1982-05-01

    The formation of neutron deficient nuclei by heavy ion reactions is investigated. The experimental technique is presented, and the results obtained concerning Sn et In isotopes reported: first excited states of 106 Sn, high spin states in 107 Sn and 107 In; Yrast levels of 106 Sn, 107 Sn, 108 Sn; study of neutron deficient Sn and In isotopes formed by the desintegration of the compound nucleus 112 Xe. All these results are discussed [fr

  7. Structural/surface characterization and catalytic evaluation of rare-earth (Y, Sm and La) doped ceria composite oxides for CH{sub 3}SH catalytic decomposition

    Energy Technology Data Exchange (ETDEWEB)

    He, Dedong; Chen, Dingkai; Hao, Husheng; Yu, Jie; Liu, Jiangping; Lu, Jichang; Liu, Feng [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500 (China); Wan, Gengping [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500 (China); Research Center for Analysis and Measurement, Hainan University, Haikou, 570228 (China); He, Sufang [Research Center for Analysis and Measurement, Kunming University of Science and Technology, Kunming, 650093 (China); Luo, Yongming, E-mail: environcatalysis222@yahoo.com [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500 (China)

    2016-12-30

    Highlights: • Ce{sub 0.75}RE{sub 0.25}O{sub 2-δ} (RE = Y, Sm and La) were synthesized by citrate complexation method. • Ce{sub 0.75}Y{sub 0.25}O{sub 2-δ} exhibited the best stability for the decomposition of CH{sub 3}SH. • Cation radius played a key role in determining structure and surface characteristics. • Catalytic behavior depended on synergistic role of oxygen vacancies and basic sites. • Ce{sub 2}S{sub 3} accumulation on the surface was responsible for the deactivation of catalyst. - Abstract: A series of rare earth (Y, Sm and La) doped ceria composite oxides and pure CeO{sub 2} were synthesized and evaluated by conducting CH{sub 3}SH catalytic decomposition test. Several characterization studies, including XRD, BET, Raman, H{sub 2}-TPR, XPS, FT-IR, CO{sub 2}-TPD and CH{sub 3}SH-TPD, were undertaken to correlate structural and surface properties of the obtained ceria-based catalysts with their catalytic performance for CH{sub 3}SH decomposition. More oxygen vacancies and increased basic sites exhibited in the rare earth doped ceria catalysts. Y doped ceria sample (Ce{sub 0.75}Y{sub 0.25}O{sub 2-δ}), with a moderate increase in basic sites, contained more oxygen vacancies. More structural defects and active sites could be provided, and a relatively small amount of sulfur would accumulate, which resulted in better catalytic performance. The developed catalyst presented good catalytic behavior with stability very similar to that of typical zeolite-based catalysts reported previously. However, La doped ceria catalyst (Ce{sub 0.75}La{sub 0.25}O{sub 2-δ}) with the highest alkalinity was not the most active one. More sulfur species would be adsorbed and a large amount of cerium sulfide species (Ce{sub 2}S{sub 3}) would accumulate, which caused deactivation of the catalysts. The combined effect of increased oxygen vacancies and alkalinity led to the catalytic stability of Ce{sub 0.75}Sm{sub 0.25}O{sub 2-δ} sample was comparable to that of pure Ce

  8. SN 1987A. Theory

    International Nuclear Information System (INIS)

    Schaeffer, R.

    1987-03-01

    SN 1987A was unique in many aspects. The most striking, undoubtedly, is its low luminosity, nearly two orders of magnitude below the expectations based on supernovae currently observed in external galaxies. The rise time of the optical emission, usually a few days, was for SN 1987A, of the order of a few hours. Also its surface temperature is surprisingly low, 5000K. The neutrino burst has been detected. It was observed twice, with a time difference of 5 hours, the second burst occurring within 3 hours of the onset of the optical signal. In this talk, I will discuss how these strange events fit with the theoretical models of supernova explosions, how they differ in some cases, and try to evaluate the degree of certainty -or uncertainty- of our present knowledge on how these extremely powerful star explosions occur

  9. Atomic mapping of Ruddlesden-Popper faults in transparent conducting BaSnO3-based thin films.

    Science.gov (United States)

    Wang, W Y; Tang, Y L; Zhu, Y L; Suriyaprakash, J; Xu, Y B; Liu, Y; Gao, B; Cheong, S-W; Ma, X L

    2015-11-03

    Doped BaSnO3 has arisen many interests recently as one of the promising transparent conducting oxides for future applications. Understanding the microstructural characteristics are crucial for the exploration of relevant devices. In this paper, we investigated the microstructural features of 0.001% La doped BaSnO3 thin film using both conventional and aberration corrected transmission electron microscopes. Contrast analysis shows high densities of Ruddlesden-Popper faults in the film, which are on {100} planes with translational displacements of 1/2a  . Atomic EELS element mappings reveal that the Ruddlesden-Popper faults are Ba-O layer terminated, and two kinds of kink structures at the Ruddlesden-Popper faults with different element distributions are also demonstrated. Quantitative analysis on lattice distortions of the Ruddlesden-Popper faults illustrates that the local lattice spacing poses a huge increment of 36%, indicating that large strains exist around the Ruddlesden-Popper faults in the film.

  10. SN 2006oz

    DEFF Research Database (Denmark)

    Leloudas, Georgios; Chatzopoulos, E.; Dilday, B.

    2012-01-01

    to contribute to a better understanding of these objects by studying SN 2006oz, a newly-recognized member of this class. Methods. We present multi-color light curves of SN 2006oz from the SDSS-II SN Survey that cover its rise time, as well as an optical spectrum that shows that the explosion occurred at z ~ 0.......376. We fitted black-body functions to estimate the temperature and radius evolution of the photosphere and used the parametrized code SYNOW to model the spectrum. We constructed a bolometric light curve and compared it with explosion models. In addition, we conducted a deep search for the host galaxy...... to a recombination wave in a circumstellar medium (CSM) and discuss whether this is a common property of all similar explosions. The subsequent rise can be equally well described by input from a magnetar or by ejecta-CSM interaction, but the models are not well constrained owing to the lack of post...

  11. All-perovskite transparent high mobility field effect using epitaxial BaSnO3 and LaInO3

    Directory of Open Access Journals (Sweden)

    Useong Kim

    2015-03-01

    Full Text Available We demonstrate an all-perovskite transparent heterojunction field effect transistor made of two lattice-matched perovskite oxides: BaSnO3 and LaInO3. We have developed epitaxial LaInO3 as the gate oxide on top of BaSnO3, which were recently reported to possess high thermal stability and electron mobility when doped with La. We measured the dielectric properties of the epitaxial LaInO3 films, such as the band gap, dielectric constant, and the dielectric breakdown field. Using the LaInO3 as a gate dielectric and the La-doped BaSnO3 as a channel layer, we fabricated field effect device structure. The field effect mobility of such device was higher than 90 cm2 V−1 s−1, the on/off ratio was larger than 107, and the subthreshold swing was 0.65 V dec−1. We discuss the possible origins for such device performance and the future directions for further improvement.

  12. All-perovskite transparent high mobility field effect using epitaxial BaSnO{sub 3} and LaInO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Useong; Park, Chulkwon; Kim, Young Mo; Ju, Chanjong; Park, Jisung; Char, Kookrin, E-mail: kchar@phya.snu.ac.kr [Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Ha, Taewoo; Kim, Jae Hoon [Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Namwook; Yu, Jaejun [Center for Theoretical Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-03-01

    We demonstrate an all-perovskite transparent heterojunction field effect transistor made of two lattice-matched perovskite oxides: BaSnO{sub 3} and LaInO{sub 3}. We have developed epitaxial LaInO{sub 3} as the gate oxide on top of BaSnO{sub 3}, which were recently reported to possess high thermal stability and electron mobility when doped with La. We measured the dielectric properties of the epitaxial LaInO{sub 3} films, such as the band gap, dielectric constant, and the dielectric breakdown field. Using the LaInO{sub 3} as a gate dielectric and the La-doped BaSnO{sub 3} as a channel layer, we fabricated field effect device structure. The field effect mobility of such device was higher than 90 cm{sup 2} V{sup −1} s{sup −1}, the on/off ratio was larger than 10{sup 7}, and the subthreshold swing was 0.65 V dec{sup −1}. We discuss the possible origins for such device performance and the future directions for further improvement.

  13. pn junctions based on a single transparent perovskite semiconductor BaSnO3

    Science.gov (United States)

    Kim, Hoon Min; Kim, Useong; Park, Chulkwon; Kwon, Hyukwoo; Lee, Woongjae; Kim, Tai Hoon; Kim, Kee Hoon; Char, Kookrin; Mdpl, Department Of Physics; Astronomy Team; Censcmr, Department Of Physics; Astronomy Team

    2014-03-01

    Successful p doping of transparent oxide semiconductor will further increase its potential, especially in the area of optoelectronic applications. We will report our efforts to dope the BaSnO3 (BSO) with K by pulsed laser deposition. Although the K doped BSO exhibits rather high resistivity at room temperature, its conductivity increases dramatically at higher temperatures. Furthermore, the conductivity decreases when a small amount of oxygen was removed from the film, consistent with the behavior of p type doped oxides. We have fabricated pn junctions by using K doped BSO as a p type and La doped BSO as an n type material. I_V characteristics of these devices show the typical rectifying behavior of pn junctions. We will present the analysis of the junction properties from the temperature dependent measurement of their electrical properties, which shows that the I_V characteristics are consistent with the material parameters such as the carrier concentration, the mobility, and the bandgap. Our demonstration of pn junctions based on a single transparent perovskite semiconductor further enhances the potential of BSO system with high mobility and stability.

  14. Influence of La doping and synthesis method on the properties of CoFe{sub 2}O{sub 4} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, S.F. [Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Hemeda, O.M. [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); El-Dek, S.I., E-mail: didi5550000@gmail.com [Materials Science and Nanotechnology Department, Faculty of Post Graduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef (Egypt); Salem, B.I. [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt)

    2016-12-15

    Nanocrystals of La doped CoFe{sub 2}O{sub 4} were synthesized using three different techniques: flash autocombustion, citrate–nitrate and the standard ceramic technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the obtained nanocrystals. All samples were crystallized in a spinel structure with cubic symmetry. The decrease in the lattice constant was endorsed to the large difference in ionic radii of both La{sup +3} (1.216 Å) and Fe (0.65 Å) in 6-f coordination. The citrate method displayed superior M{sub s} values amongst all techniques. The coercivity was found to exhibit largest values for the citrate method and then the flash while smallest values are associated with ceramic technique. - Highlights: • CoLa{sub x}Fe{sub 2−x}O{sub 4} nanocrystals crystallized in spinel cubic structure using 3 techniques. • The decrease in the lattice constant is due to the difference in ionic radius of La{sup +3} and Fe{sup 3+}. • The citrate method exhibit largest values of M{sub s} amongst all techniques. • Coercivity exhibits largest values for citrate and then flash, smallest for ceramic technique.

  15. Effect of oxygen vacancy distribution on the thermoelectric properties of La-doped SrTiO3 epitaxial thin films

    KAUST Repository

    Sarath Kumar, S. R.; Abutaha, Anas I.; Hedhili, Mohamed N.; Alshareef, Husam N.

    2012-01-01

    A detailed study of the role of oxygen vacancies in determining the effective mass and high temperature (300–1000 K) thermoelectricproperties of La-doped epitaxial SrTiO3 thin films is presented. It is observed that at intermediate temperatures, a transition from degenerate to non-degenerate behavior is observed in the Seebeck coefficient, but not electrical conductivity, which is attributed to heterogeneous oxygen non-stoichiometry. Heikes formula is found to be invalid for the films with oxygen vacancies. By fitting the spectroscopic ellipsometry (SE) data, obtained in the range 300–2100 nm, using a Drude-Lorentz dispersion relation with two Lorentz oscillators, the electrical and optical properties of the films are extracted. Using the excellent agreement between the transport properties extracted from SE modeling and direct electrical measurements, we demonstrate that an increase in concentration of oxygen vacancies results in a simultaneous increase of both carrier concentration and electron effective mass, resulting in a higher power factor.

  16. Effect of oxygen vacancy distribution on the thermoelectric properties of La-doped SrTiO3 epitaxial thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2012-12-03

    A detailed study of the role of oxygen vacancies in determining the effective mass and high temperature (300–1000 K) thermoelectricproperties of La-doped epitaxial SrTiO3 thin films is presented. It is observed that at intermediate temperatures, a transition from degenerate to non-degenerate behavior is observed in the Seebeck coefficient, but not electrical conductivity, which is attributed to heterogeneous oxygen non-stoichiometry. Heikes formula is found to be invalid for the films with oxygen vacancies. By fitting the spectroscopic ellipsometry (SE) data, obtained in the range 300–2100 nm, using a Drude-Lorentz dispersion relation with two Lorentz oscillators, the electrical and optical properties of the films are extracted. Using the excellent agreement between the transport properties extracted from SE modeling and direct electrical measurements, we demonstrate that an increase in concentration of oxygen vacancies results in a simultaneous increase of both carrier concentration and electron effective mass, resulting in a higher power factor.

  17. Isomer shifts and chemical bonding in crystalline Sn(II) and Sn(IV) compounds

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1991-01-01

    First-principles self-consistent Local Density calculations of the electronic structure of clusters representing Sn(II) (SnO, SnF 2 , SnS, SnSe) and Sn(IV) (SnO 2 , SnF 4 ) crystalline compounds were performed. Values of the electron density at the Sn nucleus were obtained and related to measured values of the Moessbauer Isomer Shifts reported in the literature. The nuclear parameter of 119 Sn derived was ΔR/R=(1.58±0.14)x10 -4 . The chemical bonding in the solids was analysed and related to the electron densities obtained. (author)

  18. Electrochemical Performance of a Carbon Nanotube/La-Doped TiO2 Nanocomposite and its Use for Preparation of an Electrochemical Nicotinic Acid Sensor

    Directory of Open Access Journals (Sweden)

    Hanxing Liu

    2008-11-01

    Full Text Available A carbon nanotube/La-doped TiO2 (La-TiO2 nanocomposite (CLTN was prepared by a procedure similar to a complex/adsorption process. Scanning electron microscopy (SEM images show that the La-TiO2 distributes on the carbon nanotube walls. The CLTN was mixed with paraffin to form a CLTN paste for the CLTN paste electrode (CLTNPE. The electrochemical characteristics of CLTNPE were compared with that of conventional carbon electrodes such as the carbon paste electrode (CPE and glass carbon electrode (GC. The CLTNPE exhibits electrochemical activity and was used to investigate the electrochemistry of nicotinic acid (NA. The modified electrode has a strong electrocatalytic effect on the redox of NA. The cyclic voltammetry (CV redox potential of NA at the CLTNPE is 320 mV. The oxidation process of NA on the CLTNPE is pH dependent. A sensitive chronoamperometric response for NA was obtained covering a linear range from 1.0×10-6 mol·L-1 to 1.2×10-4 mol·L-1, with a detection limit of 2.7×10-7 mol·L-1. The NA sensor displays a remarkable sensitivity and stability. The mean recovery of NA in the human urine is 101.8%, with a mean variation coefficient (RSD of 2.6%.

  19. Effect of thickness and composition on the structure and ordering in La-doped intergranular films between Si{sub 3}N{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yun [Interfacial Molecular Science Laboratory, Department of Materials Science and Engineering, Rutgers University, 607 Taylor Rd., Piscataway, NJ 08855 (United States); Garofalini, Stephen H., E-mail: shg@rutgers.edu [Interfacial Molecular Science Laboratory, Department of Materials Science and Engineering, Rutgers University, 607 Taylor Rd., Piscataway, NJ 08855 (United States)

    2011-08-15

    Molecular dynamics simulations were used to determine the effect of the composition and thickness on the atomistic structure of La-Si-O-N intergranular films (IGFs) between prism and misaligned high-index silicon nitride crystals. Results showed that ordered La adsorption onto the prism-terminated surface is not affected by the orientation of the opposing crystal, although the extent of the ordering away from the interface is affected by IGF thickness. La adsorption at ordered sites 1 and 2 on the prism surface occurred for almost all of the compositions in both 1.8 and 0.6 nm thick IGFs and at sites farther from the prism interface in the thicker IGF, similar to adsorption in triple points. La adsorption on the prism surface occurred at sites precisely the same as seen in high-angle annular dark field scanning transmission electron microscopy studies. Saturation of available sites is affected by the thickness of the IGF, which governs the number of La ions (and N ions) in the IGF, with lower site filling in the thinner IGF. There are clear energy differences for La in the interior of the IGF vs. the interface based on composition and IGF thickness, with the thicker IGF showing greater variation in driving forces for segregation or La incorporation into the IGF. Fracture is affected by both composition and thickness and occurs in the glassy IGF and not in the ordered interfacial regions, consistent with experimentally observed intergranular fracture for La-doped silicon nitride. Segregation of La to the interface affects N distribution within the interior of the IGF, which affects strength.

  20. Al-, Y-, and La-doping effects favoring intrinsic and field induced ferroelectricity in HfO2: A first principles study

    Science.gov (United States)

    Materlik, Robin; Künneth, Christopher; Falkowski, Max; Mikolajick, Thomas; Kersch, Alfred

    2018-04-01

    III-valent dopants have shown to be most effective in stabilizing the ferroelectric, crystalline phase in atomic layer deposited, polycrystalline HfO2 thin films. On the other hand, such dopants are commonly used for tetragonal and cubic phase stabilization in ceramic HfO2. This difference in the impact has not been elucidated so far. The prospect is a suitable doping to produce ferroelectric HfO2 ceramics with a technological impact. In this paper, we investigate the impact of Al, Y, and La doping, which have experimentally proven to stabilize the ferroelectric Pca21 phase in HfO2, in a comprehensive first-principles study. Density functional theory calculations reveal the structure, formation energy, and total energy of various defects in HfO2. Most relevant are substitutional electronically compensated defects without oxygen vacancy, substitutional mixed compensated defects paired with a vacancy, and ionically compensated defect complexes containing two substitutional dopants paired with a vacancy. The ferroelectric phase is strongly favored with La and Y in the substitutional defect. The mixed compensated defect favors the ferroelectric phase as well, but the strongly favored cubic phase limits the concentration range for ferroelectricity. We conclude that a reduction of oxygen vacancies should significantly enhance this range in Y doped HfO2 thin films. With Al, the substitutional defect hardly favors the ferroelectric phase before the tetragonal phase becomes strongly favored with the increasing concentration. This could explain the observed field induced ferroelectricity in Al-doped HfO2. Further Al defects are investigated, but do not favor the f-phase such that the current explanation remains incomplete for Al doping. According to the simulation, doping alone shows clear trends, but is insufficient to replace the monoclinic phase as the ground state. To explain this fact, some other mechanism is needed.

  1. Influence of difference quantity La-doped TiO{sub 2} photoanodes on the performance of dye-sensitized solar cells: A strategy for choosing an appropriate doping quantity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zige; Li, Guoxiang; Cui, Zijian; Zhang, Kaiyue; Feng, Yaqing [School of Chemical Engineering and Technology, Tianjin University, Weijin Roard 92#, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Weijin Roard 92#, Tianjin 300072 (China); Meng, Shuxian, E-mail: msxmail@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Weijin Roard 92#, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Weijin Roard 92#, Tianjin 300072 (China)

    2016-05-15

    Facilitated by TiO{sub 2} particles adsorbing lanthanide ions in hydrosol, La-doped TiO{sub 2} was produced by a hydrothermal method. The structure, optical and photoluminescence properties of down-converting photoelectrode with the La{sup 3+} were characterized by X-ray (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray detector (EDX) and N{sub 2} adsorption-desorption isotherms measurement. The photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) fabricated with 0.05 g-La/TiO{sub 2} reached 7.02%, which gave an efficiency improved by 10.36% compared with that of cells fabricated from pure TiO{sub 2}. The improvement in efficiency was ascribed to more dyes adsorbed on the surface of TiO{sub 2}. - Graphical abstract: (a) J–V curves of La-doped photoelectrodes with different La(NO{sub 3}){sub 3}·6H{sub 2}O amounts; (b) the curves of efficiency changing with the amount of La(NO{sub 3}){sub 3}·6H{sub 2}O. The photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) fabricated with 0.05 g-La/TiO{sub 2} reached 7.02%, which gave an efficiency improved by 10.36% compared with that of cells fabricated from pure TiO{sub 2}.

  2. Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

    International Nuclear Information System (INIS)

    Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

    2014-01-01

    Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

  3. PROTEUS-SN User Manual

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, Emily R. [Argonne National Lab. (ANL), Argonne, IL (United States); Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, Changho [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-16

    PROTEUS-SN is a three-dimensional, highly scalable, high-fidelity neutron transport code developed at Argonne National Laboratory. The code is applicable to all spectrum reactor transport calculations, particularly those in which a high degree of fidelity is needed either to represent spatial detail or to resolve solution gradients. PROTEUS-SN solves the second order formulation of the transport equation using the continuous Galerkin finite element method in space, the discrete ordinates approximation in angle, and the multigroup approximation in energy. PROTEUS-SN’s parallel methodology permits the efficient decomposition of the problem by both space and angle, permitting large problems to run efficiently on hundreds of thousands of cores. PROTEUS-SN can also be used in serial or on smaller compute clusters (10’s to 100’s of cores) for smaller homogenized problems, although it is generally more computationally expensive than traditional homogenized methodology codes. PROTEUS-SN has been used to model partially homogenized systems, where regions of interest are represented explicitly and other regions are homogenized to reduce the problem size and required computational resources. PROTEUS-SN solves forward and adjoint eigenvalue problems and permits both neutron upscattering and downscattering. An adiabatic kinetics option has recently been included for performing simple time-dependent calculations in addition to standard steady state calculations. PROTEUS-SN handles void and reflective boundary conditions. Multigroup cross sections can be generated externally using the MC2-3 fast reactor multigroup cross section generation code or internally using the cross section application programming interface (API) which can treat the subgroup or resonance table libraries. PROTEUS-SN is written in Fortran 90 and also includes C preprocessor definitions. The code links against the PETSc, METIS, HDF5, and MPICH libraries. It optionally links against the MOAB library and

  4. Sn whiskers removed by energy photo flashing

    International Nuclear Information System (INIS)

    Jiang, N.; Yang, M.; Novak, J.; Igor, P.; Osterman, M.

    2012-01-01

    Highlights: ► Sn whiskers were sintered by intense light flashing (Photosintering). ► Photosintering can effectively eliminate Sn whiskers. ► Photosintering would not damage electronic devices. ► Photosintering is a very promising approach to improve Sn-based electronic surface termination. - Abstract: Sn whiskers have been known to be the major issue resulting in electronic circuit shorts. In this study, we present a novel energy photo flashing approach (photosintering) to shorten and eliminate Sn whiskers. It has been found that photosintering is very effective to modify and remove Sn whiskers; only a sub-millisecond duration photosintering can amazingly get rid of over 90 vol.% of Sn whiskers. Moreover, this photosintering approach has also been proved to cause no damages to electronic devices, suggesting it is a potentially promising way to improve Sn-based electronic surface termination.

  5. La5Zn2Sn

    Directory of Open Access Journals (Sweden)

    Igor Oshchapovsky

    2011-11-01

    Full Text Available A single crystal of pentalanthanum dizinc stannide, La5Zn2Sn, was obtained from the elements in a resistance furnace. It belongs to the Mo5SiB2 structure type, which is a ternary ordered variant of the Cr5B3 structure type. The space is filled by bicapped tetragonal antiprisms from lanthanum atoms around tin atoms sharing their vertices. Zinc atoms fill voids between these bicapped tetragonal antiprisms. All four atoms in the asymmetric unit reside on special positions with the following site symmetries: La1 (..m; La2 (4/m..; Zn (m.2m; Sn (422.

  6. Ordered CoSn-type ternary phases in Co3Sn3-xGex

    DEFF Research Database (Denmark)

    Allred, Jared M.; Jia, Shuang; Bremholm, Martin

    2012-01-01

    . By taking advantage of the chemical differences between the two crystallographically inequivalent Sn sites in the structure, we observe ordered ternary phases, nominally Co3SnGe2 and Co3Sn2Ge. The electron count and unit cell configuration remain unchanged from CoSn; these observations thus help to clarify...

  7. Fabrication of textured SnO2 transparent conductive films using self-assembled Sn nanospheres

    Science.gov (United States)

    Fukumoto, Michitaka; Nakao, Shoichiro; Hirose, Yasushi; Hasegawa, Tetsuya

    2018-06-01

    We present a novel method to fabricate textured surfaces on transparent conductive SnO2 films by processing substrates through a bottom-up technique with potential for industrially scalable production. The substrate processing consists of three steps: deposition of precursor Sn films on glass substrates, formation of a self-assembled Sn nanosphere layer with reductive annealing, and conversion of Sn to SnO2 by oxidative annealing. Ta-doped SnO2 films conformally deposited on the self-assembled nanospherical SnO2 templates exhibited attractive optical and electrical properties, namely, enhanced haze values and low sheet resistances, for applications as transparent electrodes in photovoltaics.

  8. Magnetic behaviour of cerium in Ce2 Sn5 and Ce3 Sn7, surstructures of Ce Sn3

    International Nuclear Information System (INIS)

    Stunault, A.

    1988-07-01

    The compound studied, Ce 2 Sn 5 and Ce 3 Sn 7 are both orthorhombic, surstructure of cubic Ce Sn 3 . Magnetic susceptibility measurements show in both compounds an antiferromagnetic order at low temperature and magnetization shows a high anisotropy. Magnetization densities are determined by polarized neutron diffraction. The cerium site which has two Ce atoms as nearest neighbourgs carries all the magnetism in both structures. For Ce 2 Sn 5 moments are directed as the high magnetization axis and structure is modulated. Ce 3 Sn 7 presents a simple antiferromagnetic order but moment are directed as low magnetization axis. Various transitions towards a ferromagnetic order are presented. Results are interpreted by measuring the difference between energy levels of crystalline field. A model of crystalline field and isotrope exchange agrees well with Ce 3 Sn 7 , but for Ce 2 Sn 7 it is necessary to reduce the magnetic moment which is typical of the Kondo effect [fr

  9. Electronic structure and isomer shifts of Sn halides

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1988-01-01

    The all-electron first-principles Discrete Variational method was employed to study the electronic structure of SnF 4 , SnCl 4 , SnBr 4 and SnI 4 . Values of the electronic density at the Sn nucleus were derived and related to 119 Sn Isomer Shifts to obtain the nuclear constant Δ 2 >. Differences in values of ρ(o) area discussed in terms of the chemical bonding between Sn and halogen atoms. (author) [pt

  10. Pseudomorphic GeSiSn, SiSn and Ge layers in strained heterostructures

    Science.gov (United States)

    Timofeev, V. A.; Nikiforov, A. I.; Tuktamyshev, A. R.; Mashanov, V. I.; Loshkarev, I. D.; Bloshkin, A. A.; Gutakovskii, A. K.

    2018-04-01

    The GeSiSn, SiSn layer growth mechanisms on Si(100) were investigated and the kinetic diagrams of the morphological GeSiSn, SiSn film states in the temperature range of 150 °C-450 °C at the tin content from 0% to 35% were built. The phase diagram of the superstructural change on the surface of Sn grown on Si(100) in the annealing temperature range of 0 °C-850 °C was established. The specular beam oscillations were first obtained during the SiSn film growth from 150 °C to 300 °C at the Sn content up to 35%. The transmission electron microscopy and x-ray diffractometry data confirm the crystal perfection and the pseudomorphic GeSiSn, SiSn film state, and also the presence of smooth heterointerfaces between GeSiSn or SiSn and Si. The photoluminescence for the multilayer periodic GeSiSn/Si structures in the range of 0.6-0.8 eV was detected. The blue shift with the excitation power increase is observed suggesting the presence of a type II heterostructure. The creation of tensile strained Ge films, which are pseudomorphic to the underlying GeSn layer, is confirmed by the results of the formation and analysis of the reciprocal space map in the x-ray diffractometry. The tensile strain in the Ge films reached the value in the range of 0.86%-1.5%. The GeSn buffer layer growth in the Sn content range from 8% to 12% was studied. The band structure of heterosystems based on pseudomorphic GeSiSn, SiSn and Ge layers was calculated and the valence and conduction band subband position dependences on the Sn content were built. Based on the calculation, the Sn content range in the GeSiSn, SiSn, and GeSn layers, which corresponds to the direct bandgap GeSiSn, SiSn, and Ge material, was obtained.

  11. Effects of interlayer Sn-Sn lone pair interaction on the band gap of bulk and nanosheet SnO

    Science.gov (United States)

    Umezawa, Naoto; Zhou, Wei

    2015-03-01

    Effects of interlayer lone-pair interactions on the electronic structure of SnO are firstly explored by the density-functional theory. Our comprehensive study reveals that the band gap of SnO opens as increase in the interlayer Sn-Sn distance. The effect is rationalized by the character of band edges which consists of bonding and anti-bonding states from interlayer lone pair interactions. The band edges for several nanosheets and strained double-layer SnO are estimated. We conclude that the double-layer SnO is a promising material for visible-light driven photocatalyst for hydrogen evolution. This work is supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) program.

  12. Controlling the antibacterial activity of CuSn thin films by varying the contents of Sn

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yujin; Park, Juyun; Kim, Dong-Woo; Kim, Hakjun; Kang, Yong-Cheol, E-mail: yckang@pknu.ac.kr

    2016-12-15

    Highlights: • We deposit CuSn thin films on a Si substrate with various Cu/Sn ratio. • Antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time increased. • XPS was utilized to assign the chemical environment of CuSn thin films before and after antibacterial test. - Abstract: We investigated antibacterial activity of CuSn thin films against Gram positive Staphylococcus aureus (S. aureus). CuSn thin films with different Cu to Sn ratios were deposited on Si(100) by radio frequency (RF) magnetron sputtering method using Cu and Sn metal anodes. The film thickness was fixed at 200 nm by varying the sputtering time and RF power on the metal targets. The antibacterial test was conducted in various conditions such as different contact times and Cu to Sn ratios in the CuSn films. The antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time between the film and bacteria suspension increased execpt in the case of CuSn-83. The oxidation states of Cu and Sn and the chemical composition of CuSn thin films before and after the antibacterial test were investigated by X-ray photoelectron spectroscopy (XPS). When the contact time was fixed, the Cu species was further oxidized as the RF power on Cu target increased. The intensity of Sn 3d decreased with increasing Cu ratio. When the sample was fixed, the peak intensity of Sn 3d decreased as the contact time increased due to the permeation of Sn into the cell.

  13. SN1987A's Twentieth Anniversary

    Science.gov (United States)

    2007-02-01

    Looking back at 20 Years of Observations of this Supernova with ESO telescopes The unique supernova SN 1987A has been a bonanza for astrophysicists. It provided several observational 'firsts,' like the detection of neutrinos from an exploding star, the observation of the progenitor star on archival photographic plates, the signatures of a non-spherical explosion, the direct observation of the radioactive elements produced during the blast, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material. ESO PR Photo 08a/07 ESO PR Photo 08a/07 SN1987A in the Large Magellanic Cloud Today, it is exactly twenty years since the explosion of Supernova 1987A in the Large Magellanic Cloud was first observed, at a distance of 163,000 light-years. It was the first naked-eye supernova to be seen for 383 years. Few events in modern astronomy have met with such an enthusiastic response by the scientists and now, after 20 years, it continues to be an extremely exciting object that is further studied by astronomers around the world, in particular using ESO's telescopes. When the first signs of Supernova 1987A, the first supernova of the year 1987, were noticed early on 24 February of that year, it was clear that this would be an unusual event. It was discovered by naked-eye and on a panoramic photographic plate taken with a 10-inch astrograph on Las Campanas in Chile by Oscar Duhalde and Ian Shelton, respectively. A few hours earlier, still on 23 February, two large underground detectors - in Japan and the USA - had registered the passage of high-energy neutrinos. Since SN 1987A exploded in the Large Magellanic Cloud (LMC), it was only accessible to telescopes in the Southern Hemisphere, more particularly in Australia, South Africa, and South America. In Chile, ESO's observatory at La Silla with its armada of telescopes with sizes between 0.5 and 3.6-m, played an important role. ESO PR Photo 08c/07 ESO PR Photo 08c/07 The

  14. STRESS a SN survey at ESO

    Science.gov (United States)

    Botticella, M. T.

    We performed the Southern inTermediate Redshift ESO Supernova Search (STRESS), a survey specifically designed to measure the rate of both SNe Ia and CC SNe, in order to obtain a direct comparison of the high redshift and local rates and to investigate the dependence of the rates on specific galaxy properties, most notably their colour. We found that the type Ia SN rate, at mean redshift z = 0.3, is 0.22+0.10+0.16-0.08-0.14 h270 SNu, while the CC SN rate, at z = 0.21, is 0.82+0.31+0.300.24-0.26 h270 SNu. The quoted errors are the statistical and systematic uncertainties. With respect to the local value, the CC SN rate at z = 0.2 is higher by a factor of ˜ 2, whereas the type Ia SN rate remains almost constant. We also measured the SN rates in the red and blue galaxies and found that the SN Ia rate seems to be constant in galaxies of different colour, whereas the CC SN rate seems to peak in blue galaxies, as in the local Universe. Finally we exploited the link between SFH and SN rates to predict the evolutionary behaviour of the SN rates and compare it with the path indicated by observations.

  15. Analyses of the Sn IX-Sn XII spectra in the EUV region

    International Nuclear Information System (INIS)

    Churilov, S S; Ryabtsev, A N

    2006-01-01

    The Sn IX-Sn XII spectra excited in a vacuum spark have been analysed in the 130-160 A wavelength region. The analysis was based on the energy parameter extrapolation in the isonuclear Sn VI-VIII and Sn XIII-XIV sequence. 266 spectral lines belonging to the 4d m -(4d m-1 4f+4p 5 4d m+1 ) (m=6-3) transition arrays were classified in the Sn IX-Sn XII spectra for the first time. All 18 level energies of the 4d 3 configuration and 39 level energies of the strongly interacting 4d 2 4f and 4p 5 4d 4 configurations were established in the Sn XII spectrum. The energy differences between the majority of the 4d m levels and about 40 levels of the 4d m-1 4f+4p 5 4d m+1 configurations were determined in each of the Sn IX, Sn X and Sn XI spectra (m=6-4). As a result, all intense lines were classified in the 130-140 A region relevant to the extreme ultraviolet (EUV) lithography. It was shown that the most of the intense lines in the 2% bandwidth at 135 A belong to the transitions in the Sn XI-Sn XIII spectra

  16. Piezoelectric properties and diffusion phase transition around PPT of La-doped (Na{sub 0.52}K{sub 0.44}Li{sub 0.04}) Nb{sub 0.8}Ta{sub 0.2}O{sub 3} lead-free piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wenlong, E-mail: yangwenlong1983@163.com; Wang, Li; Li, Haidong; Han, Junsheng; Xiu, Hanjiang; Zhou, Zhongxiang

    2016-10-01

    Lead-free ceramics (Na{sub 0.52}K{sub 0.44}Li{sub 0.04}){sub 1−3x}La{sub x}Nb{sub 0.8}Ta{sub 0.2}O{sub 3} (KNLNT-Lax, x=0.00, 0.25, 0.5, 0.75, 1.00, 1.25 mol%) as non-polluting materials were prepared by solid state reaction method. The structure, piezoelectric proprieties and temperature stability of KNLNT ceramic with different La doping concentrations were investigated. The results show a transition from orthorhombic-tetragonal mix phase to tetragonal single phase with the variation of La{sup 3+} concentrations. The SEM micrographs of surface and fractured surface show a dense microstructure with few micropores. The La-doped KNLTN ceramic will be an alternative candidate contributes to excellent piezoelectric properties, which are found in the 0.75 mol% La-doped KNLNT ceramics, with d{sub 33}=215pC/N, k{sub p}=42.8%and Q{sub m}=89. It has been remarkably improved that the temperature stability of KNLTN-Lax piezoelectric properties at room temperature, and the dielectric relaxation can be observed obviously. The mechanism of La doping was analyzed in terms of valence compensation and polymorphic phase transition (PPT) diffusion. The orthorhombic-tetragonal phase transition around room temperature and the relaxation transition were considered contributing to the excellent piezoelectric performance and improved temperature stability of La{sup 3+}-doped KNLTN.

  17. States in 118Sn from 117Sn(d,p) 118Sn at 12 MeV

    International Nuclear Information System (INIS)

    Frota-Pessoa, E.

    1983-01-01

    118 Sn energy levels up to = 5.2 MeV excitation energy are studied in the reaction 117 Sn (d,p) 118 Sn. Deuterons had a bombarding energy of 12 MeV. The protons were analized by a magnetic spectrograph. The detector was nuclear emulsion and the resolution in energy about 10 KeV. The distorted-wave analysis was used to determine l values and spectroscopic strengths. Centers of gravity and the sums of reduced spectroscopic factors are presented for the levels when it was possible to determine the S' value. 66 levels of excitation energy were found which did not appear in previous 117 Sn (d,p) reactions. 40 levels were not found previously in any reaction giving 118 Sn. The results are compared with the known ones. (Author) [pt

  18. Rod-like hierarchical Sn/SnOx@C nanostructures with enhanced lithium storage properties

    Science.gov (United States)

    Yang, Juan; Chen, Sanmei; Tang, Jingjing; Tian, Hangyu; Bai, Tao; Zhou, Xiangyang

    2018-03-01

    Rod-like hierarchical Sn/SnOx@C nanostructures have been designed and synthesized via calcining resorcinol-formaldehyde (RF) resin coated Sn-based metal-organic frameworks. The rod-like hierarchical Sn/SnOx@C nanostructures are made of a great number of carbon-wrapped primary Sn/SnOx nanospheres of 100-200 nm in diameter. The as-prepared hierarchical Sn/SnOx@C nanocomposite manifests a high initial reversible capacity of 1177 mAh g-1 and remains 1001 mAh g-1 after 240 cycles at a current density of 200 mA g-1. It delivers outstanding high-rate performance with a reversible capacity of 823 mAh g-1 even at a high current density of 1000 mA g-1. The enhanced electrochemical performances of the Sn/SnOx@C electrode are mainly attributed to the synergistic effect of the unique hierarchical micro/nanostructures and the protective carbon layer.

  19. Studying superconducting Nb3Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb3Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb3Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  20. Anomalous temperature behavior of Sn impurities

    International Nuclear Information System (INIS)

    Haskel, D.; Shechter, H.; Stern, E.A.; Newville, M.; Yacoby, Y.

    1993-01-01

    Sn impurities in Pb and Ag hosts have been investigated by Moessbauer effect and in Pb by x-ray-absorption fine-structure (XAFS) studies. The Sn atoms are dissolved up to at least 2 at. % in Pb and up to at least 8 at. % in Ag for the temperature ranges investigated. The concentration limit for Sn-Sn interactions is 1 at. % for Pb and 2 at. % for Ag as determined experimentally by lowering the Sn concentration until no appreciable change occurs in the Moessbauer effect. XAFS measurements verify that the Sn impurities in Pb are dissolved and predominantly at substitutional sites. For both hosts the temperature dependence of the spectral intensities of isolated Sn impurities below a temperature T 0 is as expected for vibrating about a lattice site. Above T 0 the Moessbauer spectral intensity exhibits a greatly increased rate of drop-off with temperature without appreciable broadening. This drop-off is too steep to be explained by ordinary anharmonic effects and can be explained by a liquidlike rapid hopping of the Sn, localized about a lattice site. Higher-entropy-density regions of radii somewhat more than an atomic spacing surround such impurities, and can act as nucleation sites for three-dimensional melting

  1. Studying superconducting Nb$_{3}$Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb$_{3}$Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb$_{3}$Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  2. Neutrino properties and supernova SN1987a

    International Nuclear Information System (INIS)

    Nussinov, S.

    1989-01-01

    The use of SN1987a to indicate how limits on neutrino properties can be deduced from the observed neutrino signals is shown. Bounds on possible deviations from relativity are briefly considered. The possible evidence for a half-millisecond pulsar in the SN remnant and on speculative attempts at finding the same periodicity in the neutrino signal are commented on. 37 refs

  3. Electrodeposition of nanostructured Sn-Zn coatings

    Science.gov (United States)

    Salhi, Y.; Cherrouf, S.; Cherkaoui, M.; Abdelouahdi, K.

    2016-03-01

    The electrodeposition of Sn-Zn coating at ambient temperature was investigated. The bath consists of metal salts SnCl2·2H2O and ZnSO4·7H2O and sodium citrate (NaC6H5Na3O7·2H2O) as complexing agent. To prevent precipitation, the pH is fixed at 5. Reducing tin and zinc through Sncit2- and ZnHcit- complex respectively is confirmed by the presence of two cathodic peaks on the voltammogram. The kinetic of tin (II) reduction process is limited by the SnCit2- dissociation. The SEM and TEM observations have showed that the coating consists of a uniform Sn-Zn layer composed of fine grains on which tin aggregates grow up. XRD revealed peaks corresponding to the hexagonal Zn phase and the tetragonal β-Sn phase.

  4. Laser spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient Sn isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The Sn isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  5. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Directory of Open Access Journals (Sweden)

    Meng Qin

    2017-06-01

    Full Text Available This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La, Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries.

  6. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Science.gov (United States)

    Qin, Meng; Li, Yueming; Lv, Xiao-Jun

    2017-01-01

    This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries. PMID:28632167

  7. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    Science.gov (United States)

    Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

    2016-03-01

    We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

  8. Sn-In-Ag phase equilibria and Sn-In-(Ag)/Ag interfacial reactions

    International Nuclear Information System (INIS)

    Chen Sinnwen; Lee Wanyu; Hsu Chiaming; Yang Chingfeng; Hsu Hsinyun; Wu Hsinjay

    2011-01-01

    Research highlights: → Thermodynamic models of Sn-In and Sn-In-Ag are developed using the CALPHAD approach. → Reaction layer in the Sn-In-(Ag)/Ag couples at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. → Reactions in the Sn-20 wt%In-2.8 wt%Ag/Ag couples are faster than those in the Sn-20 wt%In/Ag couples. - Abstract: Experimental verifications of the Sn-In and Sn-In-Ag phase equilibria have been conducted. The experimental measurements of phase equilibria and thermodynamic properties are used for thermodynamic modeling by the CALPHAD approach. The calculated results are in good agreement with experimental results. Interfacial reactions in the Sn-In-(Ag)/Ag couples have been examined. Both Ag 2 In and AgIn 2 phases are formed in the Sn-51.0 wt%In/Ag couples reacted at 100 and 150 deg. C, and only the Ag 2 In phase is formed when reacted at 25, 50 and 75 deg. C. Due to the different growth rates of different reaction phases, the reaction layer at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. In the Sn-20.0 wt%In/Ag couples, the ζ phase is formed at 250 deg. C and ζ/AgIn 2 phases are formed at 125 deg. C. Compared with the Sn-20 wt%In/Ag couples, faster interfacial reactions are observed in the Sn-20.0 wt%In-2.8 wt%Ag/Ag couples, and minor Ag addition to Sn-20 wt%In solder increases the growth rates of the reaction phases.

  9. Growth of highly textured SnS on mica using an SnSe buffer layer

    International Nuclear Information System (INIS)

    Wang, S.F.; Fong, W.K.; Wang, W.; Surya, C.

    2014-01-01

    We report the growth of SnS thin films on mica substrates by molecular beam epitaxy. Excellent 2D layered structure and strong (001) texture were observed with a record low rocking curve full width at half maximum of ∼ 0.101° for the SnS(004) diffraction. An interface model is used to investigate the nucleation of SnS on mica which indicates the co-existence of six pairs of lateral growth orientations and is in excellent agreement with the experimental Φ-scan measurements indicating 12 peaks separated by 30° from each other. To control the lateral growth of the SnS epilayers we investigate the utilization of a thin SnSe buffer layer deposited on the mica substrate prior to the growth of the SnS thin film. The excellent lattice match between SnSe and mica enhances the alignment of the nucleation of SnS and suppresses the minor lateral orientations along the mica[110] direction and its orthogonal axis. Detailed low-frequency noise measurement was performed to characterize the trap density in the films and our results clearly demonstrate substantial reduction in the density of the localized states in the SnS epilayer with the use of an SnSe buffer layer. - Highlights: • A record low rocking curve FWHM for deposited SnS on mica • Investigation of the nucleation of SnS on mica using the interface model • Investigation of nucleation mechanism by phi-scan measurement • Grain boundary formation from crystallites of various nucleation orientations • Suppression of nucleation orientations using an SnSe buffer layer

  10. Single-Particle States in $^{133}$Sn

    CERN Multimedia

    Huck, A

    2002-01-01

    % IS338 \\\\ \\\\ It is suggested to investigate the $\\beta^- $-decay of $^{133}$In and $^{134}$In in order to determine the single-particle states in $^{133}$Sn, which are so far unknown and needed for the shell-model description of the region close to $^{132}$Sn. Large hyper-pure Ge-detectors will be used for the $\\gamma$-ray spectroscopy. In the experiments with $^{134}$In, delayed neutrons in coincidence with $\\gamma$-rays from excited states in $^{133}$Sn provide the opportunity for a very selective detection of the states in question.

  11. Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, D.M. dos; Hahn, F.; Leger, J.M.; Kokoh, K.B. [Universite de Poitiers, Poitiers Cedex (France). Centre National de la Recherche Scientifique (CNRS). Equipe Electrocatalyse; Tremiliosi-Filho, G. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2008-07-01

    Ethanol oxidation has been studied on Pt-Sn and Pt-Sn-W electrodes prepared in an arc-melting furnace. Different electrochemical techniques like cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of these materials. The electro-oxidation process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. Experimental results indicated that Pt-Sn and Pt-Sn-W alloys are able to oxidize ethanol mainly to acetaldehyde and acetic acid. Adsorbed CO was also detected, demonstrating the viability of splitting the C-C bond in the ethanol molecule during the oxidation process. The adsorbed CO was further oxidized to CO{sub 2}.This reaction product was clearly detected by SNIFTIRS. Pt-Sn-W catalyst showed a better electrochemical performance than Pt-Sn that, in it turn, is better than Pt-alone. (author)

  12. Electrical and optical properties of SnEuTe and SnSrTe films

    Science.gov (United States)

    Ishida, Akihiro; Tsuchiya, Takuro; Yamada, Tomohiro; Cao, Daoshe; Takaoka, Sadao; Rahim, Mohamed; Felder, Ferdinand; Zogg, Hans

    2010-06-01

    The SnTe, Sn1-xEuxTe and Sn1-xSrxTe (x<0.06) films were prepared by hot wall epitaxy. The ternary alloy films prepared in cation rich condition had hole concentration around 1×1019 cm-3 with high mobility exceeding 2000 cm2/V s at room temperature. Optical transmission spectra were also measured in the temperature range from 100 to 400 K and compared with theoretical calculations. Optical transmission spectra of the SnTe were simulated successfully assuming bumped band edge structures. A band inversion model was proposed for the Sn1-xEuxTe and Sn1-xSrxTe systems, and the optical transmission spectra were also simulated successfully assuming the band inversion model.

  13. Lithium insertion mechanism in SnS2

    International Nuclear Information System (INIS)

    Lefebvre-Devos, I.; Olivier-Fourcade, J.; Jumas, J.C.; Lavela, P.

    2000-01-01

    We study lithium insertion in SnS 2 by means of 119 Sn Moessbauer spectroscopy, x-ray absorption spectroscopy at Sn L I,III , and S K edges, and theoretical electronic structures (calculated in the density-functional theory framework). An insertion mechanism is derived according to the Li amount. It shows the influence of the SnS 2 -layered structure on the Sn reduction, particularly the possibility of an intermediate oxidation state between Sn IV and Sn II , which is not observed during Li insertion in three-dimensional sulfides

  14. 195Pt and 119Sn Knight shifts of U3Pt3Sn4

    International Nuclear Information System (INIS)

    Kojima, K.; Takabatake, T.; Harada, A.; Hihara, T.

    1995-01-01

    The 195 Pt and 119 Sn Knight shifts in U 3 Pt 3 Sn 4 have been measured in the temperature range 4.2-298K. They exhibit Curie-Weiss like behaviors above about 50K and remain constant below about 10K. This suggests that the deviation of χ(T) from the modified Curie-Weiss law is an intrinsic property of U 3 Pt 3 Sn 4 . ((orig.))

  15. Theoretical study of electronic structures and spectroscopic properties of Ga 3Sn, GaSn 3, and their ions

    Science.gov (United States)

    Zhu, Xiaolei

    2007-01-01

    Ground and excited states of mixed gallium stannide tetramers (Ga 3Sn, Ga 3Sn +, Ga 3Sn -, GaSn 3, GaSn 3+, and GaSn 3-) are investigated employing the complete active space self-consistent-field (CASSCF), density function theory (DFT), and the coupled-cluster single and double substitution (including triple excitations) (CCSD(T)) methods. The ground states of Ga 3Sn, Ga 3Sn +, and Ga 3Sn - are found to be the 2A 1, 3B 1, and 1A 1 states in C2v symmetry with a planar quadrilateral geometry, respectively. The ground states of GaSn 3 and GaSn 3- is predicted to be the 2A 1 and 1A 1 states in C2v point group with a planar quadrilateral structure, respectively, while the ground state of GaSn 3+ is the 1A 1 state with ideal triangular pyramid C3v geometry. Equilibrium geometries, vibrational frequencies, binding energies, electron affinities, ionization energies, and other properties of Ga 3Sn and GaSn 3 are computed and discussed. The anion photoelectron spectra of Ga 3Sn - and GaSn 3- are also predicted. It is interesting to find that the amount of charge transfer between Ga and Sn 2 atoms in the 1A 1 state of GaSn 3+ greatly increases upon electron ionization from the 2A 1 state of GaSn 3, which may be caused by large geometry change. On the other hand, the results of the low-lying states of Ga 3Sn and GaSn 3 are compared with those of Ga 3Si and GaSi 3.

  16. Effect of Sn addition on the microstructure and superelasticity in Ti-Nb-Mo-Sn alloys.

    Science.gov (United States)

    Zhang, D C; Yang, S; Wei, M; Mao, Y F; Tan, C G; Lin, J G

    2012-09-01

    Ti-7.5Nb-4Mo-xSn (x=0-4at%) alloys were developed as the biomedical materials. The effect of the Sn content on the microstructure and superelasticity of the alloys was investigated. It is found that Sn is a strong stabilizer of the β phase, which is effective in suppressing the formation of α″ and ω phases in the alloys. Moreover, the Sn addition has a significant impact on the mechanical properties of the alloys. With the increase of Sn addition, the yield stress of the alloys increase, but their elastic modulus, the fracture strength and the ductility decrease, and the deformation mode of the alloys changes from (322) twining to α″ transformation and then to slip. The Ti-7.5Nb-4Mo-1Sn and Ti-7.5Nb-4Mo-3Sn alloys exhibit a good superelasticity with a high σ(SIM) due to the relatively high athermal ω phases containing or the solution hardening at room temperature. Under the maximum strain of 5%, Ti-7.5Nb-4Mo-3Sn (at%) alloy exhibits higher super elastic stability than that of Ti-7.5Nb-4Mo-1Sn alloy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Fluid sensitive nanoscale switching with quantum levitation controlled by $\\alpha$-Sn/$\\beta$-Sn phase transition

    OpenAIRE

    Boström, Mathias; Dou, Maofeng; Malyi, Oleksandr I.; Parashar, Prachi; Parsons, Drew F.; Brevik, Iver; Persson, Clas

    2018-01-01

    We analyze the Lifshitz pressure between silica and tin separated by a liquid mixture of bromobenzene and chlorobenzene. We show that the phase transition from semimetallic α−Sn to metallic β−Sn can switch Lifshitz forces from repulsive to attractive. This effect is caused by the difference in dielectric functions of α−Sn and β−Sn, giving both attractive and repulsive contributions to the total Lifshitz pressure in different frequency regions controlled by the composition of the intervening l...

  18. Oxidation of Pb-Sn and Pb-Sn-In alloys

    International Nuclear Information System (INIS)

    Sluzewski, D.A.; Chang, Y.A.; Marcotte, V.C.

    1990-01-01

    Air oxidized Pb-Sn and Pb-Sn-In single phase alloys have been studied with scanning Auger microscopy. Line scans across grain boundaries combined with argon ion sputter etching revealed grain boundary oxidation. In the Pb-Sn samples, tin is preferentially oxidized with the grain boundary regions having a much higher percentage of tin oxide than the bulk surface oxide. In the Pb-Sn-In alloys, both tin and indium are preferentially oxidized with the grain boundary regions being enriched with tin and indium oxides

  19. The crystallographic growth directions of Sn whiskers

    International Nuclear Information System (INIS)

    Stein, J.; Welzel, U.; Leineweber, A.; Huegel, W.; Mittemeijer, E.J.

    2015-01-01

    The growth directions of 55 Sn whiskers, i.e. the crystallographic orientation parallel to the whisker-growth axes, were determined using (i) a focused ion beam microscope for the determination of the physical growth angles of the whiskers with respect to a specimen (reference) coordinate system and (ii) an electron backscatter detector in a scanning electron microscope for the determination of the crystallographic orientation of the whiskers. The Sn whiskers were found to grow preferentially along low-index directions of the β-Sn crystal structure. The experimental findings of this study (and most of the results presented in the literature as well) were explained by applying, in a modified way, the Hartman–Perdok concept of periodic bond chains, i.e. chains of strong bonds running uninterruptedly through the structure, to the Sn whisker-growth phenomenon

  20. Discovery of 11 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Cacella, P.; Stone, G.; Fernandez, J. M.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.; Post, R. S.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from 14-cm telescopes in Hawaii, Texas, South Africa, and Chile, we discovered several new transient sources.

  1. Nb3Sn for Radio Frequency Cavities

    International Nuclear Information System (INIS)

    Godeke, A.

    2006-01-01

    In this article, the suitability of Nb3Sn to improve the performance of superconducting Radio-Frequency (RF) cavities is discussed. The use of Nb3Sn in RF cavities is recognized as an enabling technology to retain a very high cavity quality factor (Q0) at 4.2 K and to significantly improve the cavity accelerating efficiency per unit length (Eacc). This potential arises through the fundamental properties of Nb3Sn. The properties that are extensively characterized in the literature are, however, mainly related to improvements in current carrying capacity (Jc) in the vortex state. Much less is available for the Meissner state, which is of key importance to cavities. Relevant data, available for the Meissner state is summarized, and it is shown how this already validates the use of Nb3Sn. In addition, missing knowledge is highlighted and suggestions are given for further Meissner state specific research

  2. Beta-decay studies near 100Sn

    International Nuclear Information System (INIS)

    Rykaczewski, Krzysztof Piotr; Karny, M.; Batist, L.; Banu, A.; Becker, F.; Blazhev, A.; Burkard, K.; Bruchle, W.; Doring, J.; Faestermann, T.; Gorska, M.; Grawe, H.; Janas, Z.; Jungclaus, A.; Kavatsyuk, M.; Kavatsyuk, O.; Kirchner, R.; La Commara, M.; Mandal, S.; Mazzocchi, C.; Miernik, K.; Mukha, I.; Muralithar, S.; Plettner, C.; Plochocki, A.; Roeckl, E.; Romoli, M.; Schadel, M.; Schmidt, K.; Schwengner, R.; Zylicz, J.

    2005-01-01

    The β-decay of 102 Sn was studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). A decay scheme has been constructed based on the γ-γ coincidence data. The total experimental Gamow-Teller strength B GT exp of 102 Sn was deduced from the TAS data to be 4.2(9). A search for β-delayed γ-rays of 100 Sn decay remained unsuccessful. However, a Gamow-Teller hindrance factor h = 2.2(3), and a cross-section of about 3nb for the production of 100 Sn in fusion-evaporation reaction between 58 Ni beam and 50 Cr target have been estimated from the data on heavier tin isotopes. The estimated hindrance factor is similar to the values derived for lower shell nuclei

  3. Coulomb excitation of {sup 107}Sn

    Energy Technology Data Exchange (ETDEWEB)

    DiJulio, D.D.; Cederkall, J.; Fahlander, C. [Lund University, Physics Department, 118, Lund (Sweden); Ekstroem, A. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Hjorth-Jensen, M. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, East Lansing, MI (United States); Albers, M.; Blazhev, A.; Fransen, C.; Geibel, K.; Hess, H.; Reiter, P.; Seidlitz, M.; Taprogge, J.; Warr, N. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Bildstein, V.; Gernhaeuser, R.; Wimmer, K. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Darby, I.; Witte, H. de [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Diriken, J. [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Studiecentrum voor Kernenergie/Centre d' Etude de l' energie Nucleaire (SCK CEN), Mol (Belgium); Goergen, A.; Siem, S.; Tveten, G.M. [University of Oslo, Department of Physics, Oslo (Norway); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Lutter, R. [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Garching (Germany); Scheck, M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Walle, J.V. de [PH Department, Geneva 23 (Switzerland); Voulot, D.; Wenander, F. [AB Department, Geneva 23 (Switzerland)

    2012-07-15

    The radioactive isotope {sup 107}Sn was studied using Coulomb excitation at the REX-ISOLDE facility at CERN. This is the lightest odd-Sn nucleus examined using this technique. The reduced transition probability of the lowest-lying 3/2{sup +} state was measured and is compared to shell-model predictions based on several sets of single-neutron energies relative to {sup 100}Sn. Similar to the transition probabilities for the 2{sup +} states in the neutron-deficient even-even Sn nuclei, the measured value is underestimated by shell-model calculations. Part of the strength may be recovered by considering the ordering of the d{sub 5/2} and g{sub 7/2} single-neutron states. (orig.)

  4. Synthesis, characterization and photocatalytic performance of SnS nanofibers and SnSe nanofibers derived from the electrospinning-made SnO{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Li; Li, Dan; Dong, Xiangting; Ma, Qianli; Yu, Wensheng; Wang, Xinlu; Yu, Hui; Wang, Jinxian; Liu, Guixia, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2017-11-15

    SnO{sub 2} nanofibers were fabricated by calcination of the electrospun PVP/SnCl{sub 4} composite nanofibers. For the first time, SnS nanofibers and SnSe nanofibers were successfully synthesized by double crucible sulfurization and selenidation methods via inheriting the morphology of SnO{sub 2} nanofibers used as precursors, respectively. X-ray diffraction (XRD) analysis shows SnS nanofibers and SnSe nanofibers are respectively pure orthorhombic phase with space group of Pbnm and Cmcm. Scanning electron microscope (SEM) observation indicates that the diameters of SnS nanofibers and SnSe nanofibers are respectively 140.54±12.80 nm and 96.52±14.17 nm under the 95 % confidence level. The photocatalytic activities of samples were studied by using rhodamine B (Rh B) as degradation agent. When SnS or SnSe nanofibers are employed as the photocatalysts, the respective degradation rates of Rh B solution under the ultraviolet light irradiation after 200 min irradiation are 92.55 % and 92.86 %. The photocatalytic mechanism and formation process of SnS and SnSe nanofibers are also provided. More importantly, this preparation technique is of universal significance to prepare other metal chalcogenides nanofibers. (author)

  5. The system SnTe-InSe

    International Nuclear Information System (INIS)

    Gurshumov, A.P.; Alidzhanov, M.A.; Aliev, A.S.; Gadzhiev, T.G.; Mamedov, N.A.

    1986-01-01

    This paper discusses the nature of the interaction and physicochemical properties of the alloys of the system SnTe-InSe. The DTA was performed on an NTR-74 pyrometer, XPA on a Dron-2.0 diffractometer and MSA on an MIM-7 metallographic microscope. The microhardness of the samples was determined on a PMT-3 microhardness tester. The congruently melting compound SnInTeSe and solid solutions based on the starting components are formed in the system

  6. Advances in Nb3Sn Performance

    International Nuclear Information System (INIS)

    Godeke, Arno

    2008-01-01

    Nb 3 Sn wires with non-Cu critical current densities (J c ) that surpass 3 kAmm -2 at 12 T and 4.2 K are commercially available in piece lengths longer than 10 km. Accelerator-type magnets that utilize these conductors have achieved record magnetic fields. This article summarizes key developments in the last decade that have led to these significant improvements in the performance of Nb 3 Sn wires.

  7. In situ 119Sn Moessbauer spectroscopy used to study lithium insertion in c-Mg2Sn

    International Nuclear Information System (INIS)

    Aldon, L.; Ionica, C. M.; Lippens, P. E.; Larcher, D.; Tarascon, J.-M.; Olivier-Fourcade, J.; Jumas, J.-C.

    2006-01-01

    The electrochemical reactions of Li with c-Mg 2 Sn have been investigated by in situ Moessbauer spectroscopy of 119 Sn and X-ray diffraction. The lithiation transforms initially c-Mg 2 Sn part into Li x Mg 2 Sn alloy (x 2 MgSn ternary alloy. In situ Moessbauer spectroscopy provides valuable information on local environment of tin and swelling behavior and cracking of the particles during discharge and charge processes.

  8. Band Alignments, Valence Bands, and Core Levels in the Tin Sulfides SnS, SnS2, and Sn2S3: Experiment and Theory

    OpenAIRE

    Whittles, TJ; Burton, LA; Skelton, JM; Walsh, A; Veal, TD; Dhanak, VR

    2016-01-01

    Tin sulfide solar cells show relatively poor efficiencies despite attractive photovoltaic properties, and there is difficulty in identifying separate phases, which are also known to form during Cu2ZnSnS4 depositions. We present X-ray photoemission spectroscopy (XPS) and inverse photoemission spectroscopy measurements of single crystal SnS, SnS2, and Sn2S3, with electronic-structure calculations from density functional theory (DFT). Differences in the XPS spectra of the three phases, including...

  9. Preparation, deformation, and failure of functional Al-Sn and Al-Sn-Pb nanocrystalline alloys

    Science.gov (United States)

    Noskova, N. I.; Vil'Danova, N. F.; Filippov, Yu. I.; Churbaev, R. V.; Pereturina, I. A.; Korshunov, L. G.; Korznikov, A. V.

    2006-12-01

    Changes in the structure, hardness, mechanical properties, and friction coefficient of Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb (wt %) alloys subjected to severe plastic deformation by equal-channel angular pressing (with a force of 40 tonne) and by shear at a pressure of 5 GPa have been studied. The transition into the nanocrystalline state was shown to occur at different degrees of plastic deformation. The hardness exhibits nonmonotonic variations, namely, first it increases and subsequently decreases. The friction coefficient of the Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys quenched from the melt was found to be 0.33; the friction coefficients of these alloys in the submicrocrystalline state (after equal-channel angular pressing) equal 0.24, 0.32, and 0.35, respectively. The effect of disintegration into nano-sized powders was found to occur in the Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys after severe plastic deformation to ɛ = 6.4 and subsequent short-time holding.

  10. Electronic and magnetic properties of rare earth-Sn3 compounds for 119Sn Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sanchez, J.P.; Friedt, J.M.; Shenoy, G.K.; Percheron, A.; Achard, J.C.

    1975-01-01

    The electronic and magnetic properties of RESn 3 compounds (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Yb) have been investigated using the 23.8keV Moessbauer resonance of 119 Sn. The isomer shifts and quadrupole interactions are nearly the same in all compounds. The transferred magnetic fields and their orientation with respect to the principal electric field gradient axis at various Sn sites in the magnetically ordered state of RESn 3 (RE=Pr, Nd, Sm, Eu, Gd) have been utilized to get information about the magnetic structure. An evaluation of the transferred fields in PrSn 3 and NdSn 3 shows that the spin density at the Sn nucleus is nearly the same in both compounds [fr

  11. Liquidus Projection and Isothermal Section of the Sb-Se-Sn System

    Science.gov (United States)

    Chang, Jui-shen; Chen, Sinn-wen

    2017-12-01

    Sb-Se-Sn ternary alloys are promising chalcogenide materials. The liquidus projection and 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system are determined. Numerous Sb-Se-Sn alloys are prepared, and their primary solidification phases are examined. In addition to the three terminal phases, (Sb), (Se) and (Sn), there are Sb2Sn3, SbSn, SnSe, SnSe2, Sb2Se3, Sn2Sb9Se9, and SnSb2Se4 phases. In addition, there are two miscibility gaps along the Sb-Se and Se-Sn and sides. There are ten invariant reactions in the Sb-Se-Sn ternary system, and seven of them are experimentally determined in this study. The lowest reaction temperature of determined invariant reaction is L + SbSn = (Sn) + SnSe at 515.4 K ± 5 K (242.2 °C ± 5 °C). There are nine tie-triangles, which are Liquid + SbSn + SnSe, SbSn + SnSe + (Sb), SnSe + (Sb) + Sn2Sb9Se9, (Sb) + Sb2Se3 + Sn2Sb9Se9, SnSe + Sn2Sb9Se9 + SnSb2Se4, Sb2Se3 + Sn2Sb9Se9 + SnSb2Se4, SnSe + SnSe2 + SnSb2Se4, SnSe2 + SnSb2Se4 + Sb2Se3, and SnSe2 + Sb2Se3 + Liquid in the 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system.

  12. Noncollinear antiferromagnetic Mn3Sn films

    Science.gov (United States)

    Markou, A.; Taylor, J. M.; Kalache, A.; Werner, P.; Parkin, S. S. P.; Felser, C.

    2018-05-01

    Noncollinear hexagonal antiferromagnets with almost zero net magnetization were recently shown to demonstrate giant anomalous Hall effect. Here, we present the structural and magnetic properties of noncollinear antiferromagnetic Mn3Sn thin films heteroepitaxially grown on Y:ZrO2 (111) substrates with a Ru underlayer. The Mn3Sn films were crystallized in the hexagonal D 019 structure with c -axis preferred (0001) crystal orientation. The Mn3Sn films are discontinuous, forming large islands of approximately 400 nm in width, but are chemical homogeneous and characterized by near perfect heteroepitaxy. Furthermore, the thin films show weak ferromagnetism with an in-plane uncompensated magnetization of M =34 kA/m and coercivity of μ0Hc=4.0 mT at room temperature. Additionally, the exchange bias effect was studied in Mn3Sn /Py bilayers. Exchange bias fields up to μ0HEB=12.6 mT can be achieved at 5 K. These results show Mn3Sn films to be an attractive material for applications in antiferromagnetic spintronics.

  13. Zr-Sn-Nb alloys. Preliminary studies

    International Nuclear Information System (INIS)

    Danon, C.A.; Arias, D.E.

    1993-01-01

    Studies of the Zr-Sn-Nb diagram have been started, focussing on the Zr-rich corner, near the composition of Zirlo commercial alloy, Zr-1Sn-1Nb, and with Fe and O contents usual in nuclear grade materials. Three alloys were melted, namely Zr-4Sn-2.4Nb (A), Zr-1Sn-3Nb (B) and Zr-2.1Sn-1Nb (C). α/β transformation temperatures were measured through the variation of electrical resistivity(p) vs temperature (T). Values of 560 deg C, 670 deg C and 750 deg C were measured for the α→α+β reaction and 980 deg C, 910 deg C and 1000 deg C for the α+β→β reaction, for the A, B and C alloys, respectively in that order. Some samples were submitted to heat treatments (62 and 216 hours at 825 deg C, 120 hours at 875 deg C). Optical and scanning electronic microscopy of those samples confirmed our resistivity results. (Author)

  14. Fatigue and thermal fatigue of Pb-Sn solder joints

    International Nuclear Information System (INIS)

    Frear, D.; Grivas, D.; McCormack, M.; Tribula, D.; Morris, J.W. Jr.

    1987-01-01

    This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55 0 C and 125 0 C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb

  15. Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires

    Directory of Open Access Journals (Sweden)

    E. Karageorgou

    2014-11-01

    Full Text Available SnO2 and Sn:In2O3 nanowires were grown on Si(001, and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current–voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires were obtained by depositing copper and post-growth processing under H2S between 100 and 500 °C. These consist mainly of tetragonal rutile SnO2 and cubic bixbyite In2O3. We observe photoluminescence at 3.65 eV corresponding to band edge emission from SnO2 quantum dots in the Cu2SnS3/SnO2 nanowires due to electrostatic confinement. The Cu2SnS3/SnO2 nanowires assemblies had resistances of 100 Ω similar to CuInS2/In2O3 nanowires which exhibited photoluminescence at 3.0 eV.

  16. Phase diagram of SnTe-CdSe cross-section of SnTe+CdSe reversible SnSe+CdTe ternary reciprocal system

    International Nuclear Information System (INIS)

    Dubrovin, I.V.; Budennaya, L.D.; Mizetskaya, I.B.; Sharkina, Eh.V.

    1986-01-01

    Phase equilibrium diagram of SnTe-CdSe cross-section of Sn, Cd long Te, Se ternary reciprocal system is investigated using the methods of differential thermal, X-ray phase, and microstructural analyses. Maximum length of solid solutions on the base of SnTe corresponds to approximately 14 mol.% at 1050 K and approximately 3 mol.% of CdSe at 670 K. Region of solid solutions on the base of CdSe corresponds to less than 1 mol.% of SnTe at room temperature. SnTe-CdSe cross-section is not a quasibinar one. Equilibrium is shifted to the left in the SnTe+CdSe reversible SnSe+CdTe reciprocal system

  17. The Hubble Constant from SN Refsdal

    Science.gov (United States)

    Vega-Ferrero, J.; Diego, J. M.; Miranda, V.; Bernstein, G. M.

    2018-02-01

    Hubble Space Telescope observations from 2015 December 11 detected the expected fifth counter-image of supernova (SN) Refsdal at z = 1.49. In this Letter, we compare the time-delay predictions from numerous models with the measured value derived by Kelly et al. from very early data in the light curve of the SN Refsdal and find a best value for {H}0={64}-11+9 {km} {{{s}}}-1 {{Mpc}}-1 (68% CL), in excellent agreement with predictions from cosmic microwave background and recent weak lensing data + baryon acoustic oscillations + Big Bang nucleosynthesis (from the DES Collaboration). This is the first constraint on H 0 derived from time delays between multiple-lensed SN images, and the first with a galaxy cluster lens, subject to systematic effects different from other time-delay H 0 estimates. Additional time-delay measurements from new multiply imaged SNe will allow derivation of competitive constraints on H 0.

  18. SN REFSDAL: CLASSIFICATION AS A LUMINOUS AND BLUE SN 1987A-LIKE TYPE II SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, P. L.; Filippenko, A. V.; Graham, M. L. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Brammer, G.; Strolger, L.-G.; Riess, A. G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Selsing, J.; Hjorth, J.; Christensen, L. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Foley, R. J. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, IL 61801 (United States); Rodney, S. A. [Department of Physics and Astronomy, University of South Carolina, 712 Main St., Columbia, SC 29208 (United States); Treu, T. [University of California, Los Angeles, CA 90095 (United States); Steidel, C. C.; Strom, A.; Zitrin, A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Schmidt, K. B.; McCully, C. [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Bradač, M. [University of California, Davis, 1 Shields Avenue, Davis, CA 95616 (United States); Jha, S. W. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Graur, O., E-mail: pkelly@astro.berkeley.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States); and others

    2016-11-10

    We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in fall 2014. The HST light curve of SN Refsdal has a shape consistent with the distinctive, slowly rising light curves of SN 1987A-like SNe, and we find strong evidence for a broad H α P-Cygni profile and Na I D absorption in the HST grism spectrum at the redshift ( z = 1.49) of the spiral host galaxy. SNe IIn, largely powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and strong H α and Na I D absorption. From the grism spectrum, we measure an H α expansion velocity consistent with those of SN 1987A-like SNe at a similar phase. The luminosity, evolution, and Gaussian profile of the H α emission of the WFC3 and X-shooter spectra, separated by ∼2.5 months in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, photometry of SN Refsdal favors bluer B - V and V - R colors and one of the largest luminosities for the assumed range of potential magnifications. The evolution of the light curve at late times will provide additional evidence about the potential existence of any substantial circumstellar material. Using MOSFIRE and X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3 ± 0.1 dex and <8.4 dex, respectively) near the explosion site.

  19. Rational design of Sn/SnO{sub 2}/porous carbon nanocomposites as anode materials for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaojia [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Xifei, E-mail: xfli2011@hotmail.com [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Center for Advanced Energy Materials and Devices, Xi’an University of Technology, Xi’an 710048 (China); Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071 (China); Fan, Linlin; Yu, Zhuxin; Yan, Bo; Xiong, Dongbin; Song, Xiaosheng; Li, Shiyu [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Adair, Keegan R. [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Li, Dejun, E-mail: dejunli@mail.tjnu.edu.cn [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Sun, Xueliang, E-mail: xsun9@uwo.ca [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China)

    2017-08-01

    Highlights: • Sn/SnO{sub 2}/porous carbon nanocomposites are rationally designed via a facile strategy. • The porous carbon mitigates the volume change and poor conductivity of Sn/SnO{sub 2}. • The nanocomposites exhibit the enhanced sodium storage performance. - Abstract: Sodium-ion batteries (SIBs) have successfully attracted considerable attention for application in energy storage, and have been proposed as an alternative to lithium ion batteries (LIBs) due to the abundance of sodium resources and low price. Sn has been deemed as a promising anode material in SIBs which holds high theoretical specific capacity of 845 mAh g{sup −1}. In this work we design nanocomposite materials consisting of porous carbon (PC) with SnO{sub 2} and Sn (Sn/SnO{sub 2}/PC) via a facile reflux method. Served as an anode material for SIBs, the Sn/SnO{sub 2}/PC nanocomposite delivers the primary discharge and charge capacities of 1148.1 and 303.0 mAh g{sup −1}, respectively. Meanwhile, it can preserve the discharge capacity approximately of 265.4 mAh g{sup −1} after 50 cycles, which is much higher than those of SnO{sub 2}/PC (138.5 mAh g{sup −1}) and PC (92.2 mAh g{sup −1}). Furthermore, the Sn/SnO{sub 2}/PC nanocomposite possesses better cycling stability with 77.8% capacity retention compared to that of SnO{sub 2}/PC (61.88%) over 50 cycles. Obviously, the Sn/SnO{sub 2}/PC composite with excellent electrochemical performance shows the great possibility of application in SIBs.

  20. Physical properties of some Sn-based melts

    Directory of Open Access Journals (Sweden)

    Ilinykh N.

    2011-05-01

    Full Text Available The physical properties (viscosity, density, electroresistivity and magnetic susceptibility of pure tin, copper, silver, some binary (Sn - Ag, Sn - Cu, Sn - Bi, Sn - Zn and ternary (Sn-Ag-Cu, Sn-BiAg, Sn-Bi-Zn alloys with near eutectic compositions are investigated in wide temperature ranges. The irreversible decrease of viscosity in pure tin melt is discovered at 820 °С during heating. The similar anomaly with the following hysteresis of dynamic viscosity was fixed for binary and ternary alloys but at higher temperatures – 900 °С and 950 °С respectively. For all the systems it was shown that the alloys with eutectic compositions differ significantly in their electric and magnetic properties from hypo- and hypereutectic ones. Qualitative and quantitative metallographic analysis for Sn-3.8wt.%Ag-0.7wt.%Cu samples, heated low and above characteristic temperatures, showed the influence of melt overheating on crystallization kinetics.

  1. The 7SK snRNP associates with the little elongation complex to promote snRNA gene expression.

    Science.gov (United States)

    Egloff, Sylvain; Vitali, Patrice; Tellier, Michael; Raffel, Raoul; Murphy, Shona; Kiss, Tamás

    2017-04-03

    The 7SK small nuclear RNP (snRNP), composed of the 7SK small nuclear RNA (snRNA), MePCE, and Larp7, regulates the mRNA elongation capacity of RNA polymerase II (RNAPII) through controlling the nuclear activity of positive transcription elongation factor b (P-TEFb). Here, we demonstrate that the human 7SK snRNP also functions as a canonical transcription factor that, in collaboration with the little elongation complex (LEC) comprising ELL, Ice1, Ice2, and ZC3H8, promotes transcription of RNAPII-specific spliceosomal snRNA and small nucleolar RNA (snoRNA) genes. The 7SK snRNA specifically associates with a fraction of RNAPII hyperphosphorylated at Ser5 and Ser7, which is a hallmark of RNAPII engaged in snRNA synthesis. Chromatin immunoprecipitation (ChIP) and chromatin isolation by RNA purification (ChIRP) experiments revealed enrichments for all components of the 7SK snRNP on RNAPII-specific sn/snoRNA genes. Depletion of 7SK snRNA or Larp7 disrupts LEC integrity, inhibits RNAPII recruitment to RNAPII-specific sn/snoRNA genes, and reduces nascent snRNA and snoRNA synthesis. Thus, through controlling both mRNA elongation and sn/snoRNA synthesis, the 7SK snRNP is a key regulator of nuclear RNA production by RNAPII. © 2017 The Authors.

  2. Neutron rich nuclei around 132Sn

    International Nuclear Information System (INIS)

    Bhattacharya, Sarmishtha

    2016-01-01

    The neutron rich nuclei with few particles or holes in 132 Sn have various experimental and theoretical interest to understand the evolution of nuclear structure around the doubly magic shell closure Z=50 and N=82. Some of the exotic neutron rich nuclei in this mass region are situated near waiting points in the r-process path and are of special astrophysical interest. Neutron rich nuclei near 132 Sn have been studied using fission fragment spectroscopy. The lifetime of low lying isomeric states have been precisely measured and the beta decay from the ground and isomeric states have been characterized using gamma-ray spectroscopy

  3. Study of superconducting Nb3Sn coils

    International Nuclear Information System (INIS)

    Vivet, B.

    1963-01-01

    Composite superconducting Nb 3 Sn wires with a diameter of 0.5 mm and a length of about 100 m were made, and Hc-Ic diagrams were plotted up to fields of 80 kgauss for short lengths. Two solenoids producing fields of about 20 kgauss were studied. Nb 3 Sn solenoids, as opposed to those of Nb-Zr or Nb-Ti, appear to have a predictable behavior. Solenoids with less insulation produced stronger fields than heavily insulated solenoids. (author) [fr

  4. Aluminium stabilized Nb$-3$/Sn superconductors

    International Nuclear Information System (INIS)

    Thoener, M.; Krauth, H.; Rudolph, J.; Szulczyk, A.

    1988-01-01

    Composite superconductors made of reacted Nb 3 Sn stabilized with high purity Al were produced. Two methods were tested. The first involved soft soldering a Cu clad aluminum tape to the Nb 3 Sn conductor. In the second method the conductor, cable or monolith, was coextruded with the aluminum. Results obtained from using both methods indicated that mechanically reinforcing materials can be easily introduced into superconductors. Tests were conducted to determine magnetoresistance, electric contact resistance, yield strength, Young modulus, critical current, and other properties of the composites. Strengthening with Duratherm during coextrusion was also evaluated

  5. PbSnTe injection lasers

    International Nuclear Information System (INIS)

    Oron, M.

    1982-03-01

    Carrier confined homostructure PbSnTe lasers were developed and investigated. In this laser structure good electrical and optical confinement can be achieved by a suitable carrier concentration profile. The advantage of these lasers over PbSnTe heterostructure lasers is the perfect lattice matching between the various layers of the structure. The desired carrier concentration profile was achieved by the growth of several epitaxial layers by the LPE method on a suitable substrate. The performance of these lasers was compared with that of previous homostructure and double heterostructure lasers. (H.K.)

  6. Electronic structure and electric fields gradients of crystalline Sn(II) and Sn(IV) compounds

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1991-01-01

    The electronic structures of clusters representing crystalline compounds of Sn(II) and Sn(IV) were investigated, employing the first-principles Discrete Variational method and Local Density theory. Densities of states and related parameters were obtained and compared with experimental measurements and with results from band structure calculations. Effects of cluster size and of cluster truncated bonds are discussed. Electric field gradients at the Sn nucleus were calculated; results are analysed in terms of charge distribution and chemical bonding in the crystals. (author)

  7. Tin (Sn) for enhancing performance in silicon CMOS

    KAUST Repository

    Hussain, Aftab M.; Fahad, Hossain M.; Singh, Nirpendra; Sevilla, Galo T.; Schwingenschlö gl, Udo; Hussain, Muhammad Mustafa

    2013-01-01

    We study a group IV element: tin (Sn) by integrating it into silicon lattice, to enhance the performance of silicon CMOS. We have evaluated the electrical properties of the SiSn lattice by performing simulations using First-principle studies, followed by experimental device fabrication and characterization. We fabricated high-κ/metal gate based Metal-Oxide-Semiconductor capacitors (MOSCAPs) using SiSn as channel material to study the impact of Sn integration into silicon. © 2013 IEEE.

  8. Tin (Sn) for enhancing performance in silicon CMOS

    KAUST Repository

    Hussain, Aftab M.

    2013-10-01

    We study a group IV element: tin (Sn) by integrating it into silicon lattice, to enhance the performance of silicon CMOS. We have evaluated the electrical properties of the SiSn lattice by performing simulations using First-principle studies, followed by experimental device fabrication and characterization. We fabricated high-κ/metal gate based Metal-Oxide-Semiconductor capacitors (MOSCAPs) using SiSn as channel material to study the impact of Sn integration into silicon. © 2013 IEEE.

  9. Internal friction behavior of liquid Bi-Sn alloys

    International Nuclear Information System (INIS)

    Wu Aiqing; Guo Lijun; Liu Changsong; Jia Erguang; Zhu Zhengang

    2005-01-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480 - bar Cand another at about 830 - bar C. Only a single internal-friction peak at about 830 - bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids

  10. Internal friction behavior of liquid Bi-Sn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu Aiqing [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Guo Lijun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Liu Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Jia Erguang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)]. E-mail: zgzhu@issp.ac.cn

    2005-12-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480{sup -}bar Cand another at about 830{sup -}bar C. Only a single internal-friction peak at about 830{sup -}bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids.

  11. SiSn diodes: Theoretical analysis and experimental verification

    KAUST Repository

    Hussain, Aftab M.; Wehbe, Nimer; Hussain, Muhammad Mustafa

    2015-01-01

    We report a theoretical analysis and experimental verification of change in band gap of silicon lattice due to the incorporation of tin (Sn). We formed SiSn ultra-thin film on the top surface of a 4 in. silicon wafer using thermal diffusion of Sn

  12. Summary of George Mason University SN1987A workshop

    International Nuclear Information System (INIS)

    van den Bergh, S.

    1990-01-01

    The author summaries studies of SN 1987A. This discussion focuses on how theories of core collapse in supernovae have been confirmed by observations of neutrinos produced by SN1987A and observations of the exponential tail of the light curve of SN1987A give strong support to the prediction that this phase of supernova light curves is powered by 56 Co decay

  13. CONSTRUÇÕES BINOMINAIS DO TIPO SN1 DE SN2

    Directory of Open Access Journals (Sweden)

    Karen Sampaio Braga Alonso

    2017-04-01

    Full Text Available Este artigo tem por objetivo investigar a flutuação de sentido quantidade-qualidade licenciada pelo uso de construtos binominais do tipo SN1 de SN2, como xícara de chá, no Português do Brasil.A pesquisa é baseada na perspectiva teórica da Linguística Funcional Centrada no Uso (BYBEE, 2010; BARLOW E KEMMER, 2000; TOMASELLO, 2003, TRAUGOTT, 2008 e busca descrever as propriedades morfossintáticas, semântico-pragmáticas e cognitivas dos usos das construções que favorecem uma leitura ora qualitativa ora quantitativa, no que se refere à relação entre SN1 e SN2.

  14. Properties of second phase (BaSnO3, Sn) added-YBCO thick films

    International Nuclear Information System (INIS)

    Ban, E.; Matsuoka, Y.

    1997-01-01

    The improvement of the critical current density J c of YBCO thick films has been attempted by adding BaSnO 3 powder and ultrafine Sn particles, whose diameter is about 2 μm and 7 x 10 -2 μm, respectively. It was found that the addition of a small amount of these particles was effective for the enhancement of J c of thick films prepared by a liquid-phase processing method. The 1 wt.% BaSnO 3 films fired at T s =1040-1060 C and the 3 wt.% Sn films (T s =1030-1060 C) showed J c values (77 K, 0 T) of about 2.1-2.4 x 10 3 Acm -2 and 3.1-3.5 x 10 3 Acm -2 , respectively, as compared to 2.0 x 10 3 Acm -2 for the undoped films. (orig.)

  15. Study of rotational band in 111Sn

    International Nuclear Information System (INIS)

    Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Goswami, A.; Saha Sarkar, M.; Bhattacharya, S.; Mukherjee, A.; Mukherjee, G.; Basu, S.K.; Mukhopadhyay, S.

    2006-01-01

    The motivation of the present work is to study the negative-parity rotational band in 111 Sn. Study of the lifetimes of the states of the rotational band is expected to provide information on their structures as well as the band termination phenomenon

  16. Primordial black holes survive SN lensing constraints

    Science.gov (United States)

    García-Bellido, Juan; Clesse, Sébastien; Fleury, Pierre

    2018-06-01

    It has been claimed in [arxiv:1712.02240] that massive primordial black holes (PBH) cannot constitute all of the dark matter (DM), because their gravitational-lensing imprint on the Hubble diagram of type Ia supernovae (SN) would be incompatible with present observations. In this note, we critically review those constraints and find several caveats on the analysis. First of all, the constraints on the fraction α of PBH in matter seem to be driven by a very restrictive choice of priors on the cosmological parameters. In particular, the degeneracy between Ωm and α was ignored and thus, by fixing Ωm, transferred the constraining power of SN magnitudes to α. Furthermore, by considering more realistic physical sizes for the type-Ia supernovae, we find an effect on the SN lensing magnification distribution that leads to significantly looser constraints. Moreover, considering a wide mass spectrum of PBH, such as a lognormal distribution, further softens the constraints from SN lensing. Finally, we find that the fraction of PBH that could constitute DM today is bounded by fPBH < 1 . 09(1 . 38) , for JLA (Union 2.1) catalogs, and thus it is perfectly compatible with an all-PBH dark matter scenario in the LIGO band.

  17. Multiepoch Spectropolarimetry of SN 2011fe

    Energy Technology Data Exchange (ETDEWEB)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M. [University of Arizona, Steward Observatory, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Porter, Amber; Leising, Mark D. [118 Kinard Laboratory, Clemson University, Clemson, SC 29634 (United States)

    2017-01-20

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  18. Production and application of Sn-117m

    International Nuclear Information System (INIS)

    Vucina, J.; Nikolic, N.; Orlic, M.

    2005-01-01

    For targeted therapy in nuclear medicine, besides the usually used, like 32 P, 89 Sr, 131 I, 186,188 Re, new radioisotopes are intensively investigated. Particular interest is devoted to 117m Sn. It decays by isomeric transition with the emission of low energy conversion electrons and short range. Their potent lethality, due to high LET, particularly when the emitter is located inside the cell, on or near nucleus, is well known. The accompanying gamma rays (Eγ = 159 keV) are also suitable for detection. At present, the specific activity which can be achieved in nuclear reactors is is sufficient for the production of agents for bone palliation. The best results so far were achieved with 117m Sn(IV)-DTPA. It is expected that the use of this radioisotope will increase when a method of its production in the no-carrier form will be developed. In the paper the production of 117m Sn and 117m Sn radiopharmaceuticals is briefly reviewed. (author) [sr

  19. Multiepoch Spectropolarimetry of SN 2011fe

    International Nuclear Information System (INIS)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M.; Porter, Amber; Leising, Mark D.

    2017-01-01

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  20. Discovery of Ten ASAS-SN Supernovae

    Science.gov (United States)

    Nicholls, B.; Brimacombe, J.; Kiyota, S.; Stone, G.; Cruz, I.; Trappett, D.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the "Leavitt" telescope in Fort Davis, Texas, the "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  1. Discovery of 11 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Fernandez, J. M.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.

    2018-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the "Leavitt" telescope in Fort Davis, Texas, the "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  2. Polarographic determination of Sn (II) and total Sn in PYRO and MDP radiopharmaceutical kits

    International Nuclear Information System (INIS)

    Sebastian, Maria V.A.; Lugon, Marcelo Di M.V.; Silva, Jose L. da; Fukumori, Neuza T.O.; Pereira, Nilda P.S. de; Silva, Constancia P.G. da; Matsuda, Margareth M.N.

    2007-01-01

    A sensitive, alternative method to atom absorption spectrometry, fluorimetry or potentiometry for the evaluation of tin(II) ions (0.1- 10 mg) and total tin in radiopharmaceutical kits was investigated. Differential pulse polarography was chosen. The supporting electrolyte was H 2 SO 4 3 mol L -1 and HCl 3 mol L -1 solution. The potential was swept from -250 to -800 mV vs Ag/AgCl/saturated KCl, using a dropping mercury electrode with 1 s drop time, 50 mV s -1 scan rate, -50 mV pulse amplitude, 40 ms pulse time and 10 mV step amplitude. Pure nitrogen was used to deaerate the polarographic cell solution for 5 min, before and after each sample introduction. Oxidation of Sn(II) was made in the same sample vial by adding H 2 O 2 (hydrogen peroxide) 10 mol L -1 , at 37 deg C, in order to quantify the total Sn. The calibration curve for Sn(II) and Sn(IV) was obtained in the concentration range of 0-10 ppm from a 1000 ppm standard solution. The detection limit of Sn(II) is 0.5 ppm and for Sn(IV) is 0.6 ppm. Differential pulse polarography was performed in the pyrophosphate (PYRO) and methylenediphosphonic acid (MDP) radiopharmaceutical kits, containing 2 mg and 1 mg of SnCl 2 .2H 2 O per vial, respectively. The described method for determination of stannous ion (Sn(II)), is selective, reproducible and adequate to be used in the quality control of lyophilized reagents and it shall be performed for other cold kits produced at IPEN. (author)

  3. Study of Sn100-xMnx amorphous system by 119Sn Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Drago, V.

    1986-01-01

    Thin films of Sn 100-x Mn x amorphous alloys with large range of concentrations were procedure by vapor condensation technique on substrates at temperatures near to liquid helium. The magnetic and paramagnetic hyperfine spectra, and the ordering temperatures were measured by 119 Sn Moessbauer effect. The electrical resistivity was used for characterizing the amorphous state. All the measurements were done 'in situ'. A magnetic phase diagram is proposed. (M.C.K.) [pt

  4. Massive stars dying alone: Extremely remote environments of SN2009ip and SN2010jp

    Science.gov (United States)

    Smith, Nathan

    2014-10-01

    We propose an imaging study of the astonishingly remote environments of two recent supernovae (SNe): SN2009ip and SN2010jp. Both were unusual Type IIn explosions that crashed into dense circumstellar material (CSM) ejected by the star shortly before explosion. The favored progenitors of these SNe are very massive luminous blue variable (LBV) stars. In fact, SN2009ip presents an extraordinay case where the LBV-like progenitor was actually detected directly in archival HST data, and where we obtained spectra and photometry for numerous pre-SN eruptions. No other SN has this treasure trove of detailed information about the progenitor (not even SN1987A). SN2010jp represents a possible collapsar-powered event, since it showed evidence of a fast bipolar jet in spectra and a low 56Ni mass; this would be an analog of the black-hole forming explosions that cause gamma ray bursts, but where the relativistic jet is damped by a residual H envelope on the star. In both cases, the only viable models for these SNe involve extremely massive (initial masses of 40-100 Msun) progenitor stars. This seems at odds with their extremely remote environments in the far outskirts of their host galaxies, with no detected evidence for an underlying massive star population in ground-based data (nor in the single shallow WFPC2/F606W image of SN2009ip). Here we propose deep UV HST images to search for any mid/late O-type stars nearby, deep red images to detect any red supergiants, and an H-alpha image to search for any evidence of ongoing star formation in the vicinity. These observations will place important and demanding constraints on the initial masses and ages of these progenitors.

  5. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo; Anjum, Dalaver H.; Wang, Qingxiao; Abou-Hamad, Edy; Emsley, Lyndon; Dong, Hailin; Laveille, Paco; Li, Lidong; Samal, Akshaya Kumar; Basset, Jean-Marie

    2014-01-01

    Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as

  6. 70 °C synthesis of high-Sn content (25%) GeSn on insulator by Sn-induced crystallization of amorphous Ge

    Energy Technology Data Exchange (ETDEWEB)

    Toko, K., E-mail: toko@bk.tsukuba.ac.jp; Oya, N.; Suemasu, T. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Saitoh, N.; Yoshizawa, N. [Electron Microscope Facility, TIA, AIST, 16-1 Onogawa, Tsukuba 305-8569 (Japan)

    2015-02-23

    Polycrystalline GeSn thin films are fabricated on insulating substrates at low temperatures by using Sn-induced crystallization of amorphous Ge (a-Ge). The Sn layer stacked on the a-Ge layer (100-nm thickness each) had two roles: lowering the crystallization temperature of a-Ge and composing GeSn. Slow annealing at an extremely low temperature of 70 °C allowed for a large-grained (350 nm) GeSn layer with a lattice constant of 0.590 nm, corresponding to a Sn composition exceeding 25%. The present investigation paves the way for advanced electronic optical devices integrated on a flexible plastic substrate as well as on a Si platform.

  7. SN 2013fs and SN 2013fr: exploring the circumstellar-material diversity in Type II supernovae

    Science.gov (United States)

    Bullivant, Christopher; Smith, Nathan; Williams, G. Grant; Mauerhan, Jon C.; Andrews, Jennifer E.; Fong, Wen-Fai; Bilinski, Christopher; Kilpatrick, Charles D.; Milne, Peter A.; Fox, Ori D.; Cenko, S. Bradley; Filippenko, Alexei V.; Zheng, WeiKang; Kelly, Patrick L.; Clubb, Kelsey I.

    2018-05-01

    We present photometry and spectroscopy of SN 2013fs and SN 2013fr in the first ˜100 d post-explosion. Both objects showed transient, relatively narrow H α emission lines characteristic of SNe IIn, but later resembled normal SNe II-P or SNe II-L, indicative of fleeting interaction with circumstellar material (CSM). SN 2013fs was discovered within 8 h of explosion; one of the earliest SNe discovered thus far. Its light curve exhibits a plateau, with spectra revealing strong CSM interaction at early times. It is a less luminous version of the transitional SN IIn PTF11iqb, further demonstrating a continuum of CSM interaction intensity between SNe II-P and SNe IIn. It requires dense CSM within 6.5 × 1014 cm of the progenitor, from a phase of advanced pre-SN mass loss beginning shortly before explosion. Spectropolarimetry of SN 2013fs shows little continuum polarization (˜0.5 per cent, consistent with zero), but noticeable line polarization during the plateau phase. SN 2013fr morphed from an SN IIn at early times to an SN II-L. After the first epoch, its narrow lines probably arose from host-galaxy emission, but the bright, narrow H α emission at early times may be intrinsic to the SN. As for SN 2013fs, this would point to a short-lived phase of strong CSM interaction if proven to be intrinsic, suggesting a continuum between SNe IIn and SNe II-L. It is a low-velocity SN II-L like SN 2009kr, but more luminous. SN 2013fr also developed an infrared excess at later times, due to warm CSM dust that requires a more sustained phase of strong pre-SN mass loss.

  8. Diffusion couple studies of the Ni-Bi-Sn system

    Directory of Open Access Journals (Sweden)

    Vassilev G.

    2012-01-01

    Full Text Available Investigations of Ni-Bi-Sn system were performed in order to inquire the phase diagram and to assess some diffusion kinetic parameters. For this purpose diffusion couples consisting of solid nickel (preliminary electroplated with tin and liquid Bi-Sn phase were annealed at 370 °C. Three compositions (0.8, 0.6 and 0.4 mole fractions Sn of the Bi-Sn melts were chosen. Annealing times from 24 to 216 h were applied. The phase and chemical compositions of the contact zone were determined by means of electron scanning microscope. It was confirmed that the diffusion layers consist mainly of Ni3Sn4 but other intermetallic phases grow as well. For the first time metastable Ni-Sn phases as NiSn and NiSn8 (NiSn9 were observed in metallurgical alloys (i.e. not in electroplated samples. The existence of a ternary compound previously reported in the literature was confirmed. More than one ternary Ni-Bi-Sn compounds might possibly be admitted. A growth coefficient of (2.29 ± 0.02 x 10-15 m2 s-1 was obtained. It was found that the apparent activation energy for diffusion layers growth (18 ± 8 kJ mol-1 is inferior to that one assessed at growth from solid state Bi-Sn mixtures (88 ± 12 kJ mol-1.

  9. Local atomic structure inheritance in Ag50Sn50 melt

    International Nuclear Information System (INIS)

    Bai, Yanwen; Bian, Xiufang; Qin, Jingyu; Hu, Lina; Yang, Jianfei; Zhang, Kai; Zhao, Xiaolin; Yang, Chuncheng; Zhang, Shuo; Huang, Yuying

    2014-01-01

    Local structure inheritance signatures were observed during the alloying process of the Ag 50 Sn 50 melt, using high-temperature X-ray diffraction and ab initio molecular dynamics simulations. The coordination number N m around Ag atom is similar in the alloy and in pure Ag melts (N m  ∼ 10), while, during the alloying process, the local structure around Sn atoms rearranges. Sn-Sn covalent bonds were substituted by Ag-Sn chemical bonds, and the total coordination number around Sn increases by about 70% as compared with those in the pure Sn melt. Changes in the electronic structure of the alloy have been studied by Ag and Sn K-edge X-ray absorption spectroscopy, as well as by calculations of the partial density of states. We propose that a leading mechanism for local structure inheritance in Ag 50 Sn 50 is due to s-p dehybridization of Sn and to the interplay between Sn-s and Ag-d electrons

  10. Effects of annealing on evaporated SnS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sakrani, Samsudi; Ismail, Bakar [Universiti Teknologi Malaysia, Skudai, Johor Bahru (Malaysia). Dept. of Physics

    1994-12-31

    The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound.

  11. Effects of annealing on evaporated SnS thin films

    International Nuclear Information System (INIS)

    Samsudi Sakrani; Bakar Ismail

    1994-01-01

    The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound

  12. Polymer-SnO2 composite membranes

    DEFF Research Database (Denmark)

    Nørgaard, Casper Frydendal; Skou, Eivind Morten

    . This work utilizes the latter approach and makes use of particles of tin dioxide (SnO2). Polymer-SnO2 composite membranes were successfully prepared using an ion-exchange method. SnO2 was incorporated into membranes by ion-exchange in solutions of SnCl2 ∙ 2 H2O in methanol, followed by oxidation to SnO2...... in air. The content of SnO2 proved controllable by adjusting the concentration of the ion-exchange solution. The prepared nanocomposite membranes were characterized by powder XRD, 119Sn MAS NMR, electrochemical impedance spectroscopy, water uptake and tensile stress-strain measurements. For Nafion 117...

  13. The tin-rich copper lithium stannides: Li3Cu6Sn4 and Li2CuSn2

    International Nuclear Information System (INIS)

    Fuertauer, Siegfried; Flandorfer, Hans; Effenberger, Herta S.

    2015-01-01

    The Sn rich ternary intermetallic compounds Li 3 Cu 6 Sn 4 (CSD-427097) and Li 2 CuSn 2 (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li 3 Cu 6 Sn 4 crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe 6 Ge 6 (a = 5.095(2) Aa, c = 9.524(3) Aa; wR 2 = 0.059; 239 unique F 2 -values, 17 free variables). Li 3 Cu 6 Sn 4 is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li 2 CuSn 2 (space group I4 1 /amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR 2 = 0.033; 213 unique F 2 -values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

  14. Effect of Sn Composition in Ge1- x Sn x Layers Grown by Using Rapid Thermal Chemical Vapor Deposition

    Science.gov (United States)

    Kil, Yeon-Ho; Kang, Sukill; Jeong, Tae Soo; Shim, Kyu-Hwan; Kim, Dae-Jung; Choi, Yong-Dae; Kim, Mi Joung; Kim, Taek Sung

    2018-05-01

    The Ge1- x Sn x layers were grown by using rapid thermal chemical-vapor deposition (RTCVD) on boron-doped p-type Si (100) substrates with Sn compositions up to x = 0.83%. In order to obtain effect of the Sn composition on the structural and the optical characteristics, we utilized highresolution X-ray diffraction (HR-XRD), etch pit density (EPD), atomic force microscopy (AFM), Raman spectroscopy, and photocurrent (PC) spectra. The Sn compositions in the Ge1- x Sn x layers were found to be of x = 0.00%, 0.51%, 0.65%, and 0.83%. The root-mean-square (RMS) of the surface roughness of the Ge1- x Sn x layer increased from 2.02 nm to 3.40 nm as the Sn composition was increased from 0.51% to 0.83%, and EPD was on the order of 108 cm-2. The Raman spectra consist of only one strong peak near 300 cm-1, which is assigned to the Ge-Ge LO peaks and the Raman peaks shift to the wave number with increasing Sn composition. Photocurrent spectra show near energy band gap peaks and their peak energies decrease with increasing Sn composition due to band-gap bowing in the Ge1- x Sn x layer. An increase in the band gap bowing parameter was observed with increasing Sn composition.

  15. SnO and SnO·CoO nanocomposite as high capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Das, B., E-mail: bijoy822000@gmail.com; Reddy, M.V.; Chowdari, B.V.R, E-mail: phychowd@nus.edu.sg

    2016-02-15

    Highlights: • The preparation methods are simple, low cost and can be scaled up for large production. • SnO is cheap, non-toxic and eco-friendly. • SnO shows high reversible capacity (Theoretical reversible capacity: 875 mA h g{sup −1}). • We showed high reversible capacity and columbic efficiency for SnO and SnO based composites. • We addressed the capacity degradation by introducing secondary phase (CoO and CNT etc.) - Abstract: We prepared SnO nanoparticles (SnO–S) and SnO·CoO nanocomposites (SnO·CoO–B) as anodes for lithium ion batteries (LIBs) by chemical and ball-milling approaches, respectively. They are characterized by X-ray diffraction and TEM techniques. The Li- storage performance are evaluated by galvanostatic cycling and cyclic voltammetry. The SnO–S and SnO·CoO–B showed improved cycling performance due to their finite particle size (i.e. nano-size) and presence of secondary phase (CoO). Better cycling stability is noticed for SnO·CoO–B with the expense of their reversible capacity. Also, addition of carbon nanotubes (CNT) to SnO–S further improved the cycling performance of SnO–S. When cycled at 60 mA g{sup −1}, the first-cycle reversible capacities of 635, 590 and 460 (±10) mA h g{sup −1} are noticed for SnO–S, SnO@CNT and SnO·CoO–B, respectively. The capacity fading observed are 3.7 and 1.8 mA h g{sup −1} per cycle for SnO–S and SnO@CNT, respectively; whereas 1–1.2 mA h g{sup −1} per cycle for SnO·CoO–B. All the samples show high coulombic efficiency, 96–98% in the range of 5–50 cycles.

  16. In Situ High-Resolution Transmission Electron Microscopy (TEM) Observation of Sn Nanoparticles on SnO2 Nanotubes Under Lithiation.

    Science.gov (United States)

    Cheong, Jun Young; Chang, Joon Ha; Kim, Sung Joo; Kim, Chanhoon; Seo, Hyeon Kook; Shin, Jae Won; Yuk, Jong Min; Lee, Jeong Yong; Kim, Il-Doo

    2017-12-01

    We trace Sn nanoparticles (NPs) produced from SnO2 nanotubes (NTs) during lithiation initialized by high energy e-beam irradiation. The growth dynamics of Sn NPs is visualized in liquid electrolytes by graphene liquid cell transmission electron microscopy. The observation reveals that Sn NPs grow on the surface of SnO2 NTs via coalescence and the final shape of agglomerated NPs is governed by surface energy of the Sn NPs and the interfacial energy between Sn NPs and SnO2 NTs. Our result will likely benefit more rational material design of the ideal interface for facile ion insertion.

  17. Cryogenic in situ microcompression testing of Sn

    International Nuclear Information System (INIS)

    Lupinacci, A.; Kacher, J.; Eilenberg, A.; Shapiro, A.A.; Hosemann, P.; Minor, A.M.

    2014-01-01

    Characterizing plasticity mechanisms below the ductile-to-brittle transition temperature is traditionally difficult to accomplish in a systematic fashion. Here, we use a new experimental setup to perform in situ cryogenic mechanical testing of pure Sn micropillars at room temperature and at −142 °C. Subsequent electron microscopy characterization of the micropillars shows a clear difference in the deformation mechanisms at room temperature and at cryogenic temperatures. At room temperature, the Sn micropillars deformed through dislocation plasticity, while at −142 °C they exhibited both higher strength and deformation twinning. Two different orientations were tested, a symmetric (1 0 0) orientation and a non-symmetric (4 5 ¯ 1) orientation. The deformation mechanisms were found to be the same for both orientations

  18. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Ferracin, P.; Ghosh, A.; Hafalia, R.; Hannaford, R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2008-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb 3 Sn conductor. The goal of these magnets is to be a proof of principle that Nb 3 Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  19. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Fermilab; Brookhaven; LBL, Berkeley; Texas A-M

    2007-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  20. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2007-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb 3 Sn conductor. The goal of these magnets is to be a proof of principle that Nb 3 Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  1. The dipole response of {sup 132}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Schrock, Philipp; Aumann, Thomas; Johansen, Jacob; Schindler, Fabia [IKP, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholtzzentrum (Germany); Rossi, Dominic [Michigan State University (United States); Collaboration: R3B-Collaboration

    2015-07-01

    The Isovector Giant Dipole Resonance (IVGDR) is a well-known collective excitation in which all protons oscillate against all neutrons of a nucleus. In neutron-rich nuclei an additional low-lying dipole excitation occurs, often denoted as Pygmy Dipole Resonance (PDR). To study the PDR in exotic Sn-isotopes, an experiment has been successfully performed with the upgraded R{sup 3}B-LAND setup at GSI. The complete-kinematics measurement of all reaction participants allows for the reconstuction of the excitation energy and, hence, the extraction of the dipole strength. Presented are the main features of the experiment, the analysis concept and the current status of the analysis of the dipole response of the doubly-magic isotope {sup 132}Sn.

  2. Magnetic disaccommodation in Sn substituted magnetite

    International Nuclear Information System (INIS)

    Hernandez-Gomez, P.; Bendimya, K.; Francisco, C. de; Munoz, J.M.; Alejos, O.; Torres, C.

    2001-01-01

    The relaxation of the initial magnetic permeability has been measured in polycrystalline Sn-doped magnetite with nominal composition Sn x Fe 3-x O 4 with x ranging from x=0 to 0.6. In the temperature range between 80 and 500 K, the time decay of the initial permeability after sample demagnetization has been represented by means of isochronal disaccommodation curves, which show the presence of different relaxation processes at 250 K (IV' peak), 275 K (IV), 300 K (III), 400 K (II) and 440 K (I). This behavior is explained on the basis of the disaccommodation of vacancy-doped magnetite and another similar tetravalent substitution, as the previously analyzed Ti-doped magnetite

  3. A review and prospects for Nb3Sn superconductor development

    Science.gov (United States)

    Xu, Xingchen

    2017-09-01

    Nb3Sn superconductors have significant applications in constructing high-field (>10 T) magnets. This article briefly reviews development of Nb3Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (J c) is needed for future accelerator magnets. After a brief review of the development of Nb3Sn superconductors, the factors controlling J c are summarized and correlated with their microstructure and chemistry. The non-matrix J c of Nb3Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb3Sn phase in the non-matrix area, the upper critical field B c2, and the flux line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb3Sn fraction in subelements is ∼65%. Then, since B c2 is largely determined by the Nb3Sn stoichiometry, a thermodynamic/kinetic theory is presented to show what essentially determines the Sn content of Nb3Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb3Sn layers. Next, to improve flux pinning, previous efforts in this community to introduce additional pinning centers to Nb3Sn wires are reviewed, and an internal oxidation technique is described. Finally, prospects for further improvement of non-matrix J c of Nb3Sn conductors are discussed, and it is seen that the only opportunity for further significantly improving J c lies in improving flux pinning.

  4. Comparison of recent SnIa datasets

    International Nuclear Information System (INIS)

    Sanchez, J.C. Bueno; Perivolaropoulos, L.; Nesseris, S.

    2009-01-01

    We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization w(a) = w 0 +w 1 (1−a), according to their Figure of Merit (FoM), their consistency with the cosmological constant (ΛCDM), their consistency with standard rulers (Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)) and their mutual consistency. We find a significant improvement of the FoM (defined as the inverse area of the 95.4% parameter contour) with the number of SnIa of these datasets ((C) highest FoM, (U), (G), (D), (E), (S) lowest FoM). Standard rulers (CMB+BAO) have a better FoM by about a factor of 3, compared to the highest FoM SnIa dataset (C). We also find that the ranking sequence based on consistency with ΛCDM is identical with the corresponding ranking based on consistency with standard rulers ((S) most consistent, (D), (C), (E), (U), (G) least consistent). The ranking sequence of the datasets however changes when we consider the consistency with an expansion history corresponding to evolving dark energy (w 0 ,w 1 ) = (−1.4,2) crossing the phantom divide line w = −1 (it is practically reversed to (G), (U), (E), (S), (D), (C)). The SALT2 and MLCS2k2 fitters are also compared and some peculiar features of the SDSS-II dataset when standardized with the MLCS2k2 fitter are pointed out. Finally, we construct a statistic to estimate the internal consistency of a collection of SnIa datasets. We find that even though there is good consistency among most samples taken from the above datasets, this consistency decreases significantly when the Gold06 (G) dataset is included in the sample

  5. Discovery of 7 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Castro, N.; Clocchiatti, A.; Stone, G.; Nicholls, B.; Fernandez, J. M.; Cacella, P.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  6. Discovery of 9 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Castro, N.; Clocchiatti, A.; Cacella, P.; Wiethoff, W.; Krannich, G.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  7. Discovery of 8 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Kiyota, S.; Wiethoff, W.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  8. Discovery of Six ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.; Cornect, R.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  9. Discovery of 8 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Tomasella, Lina; Krannich, G.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.; Cacella, P.; Kiyota, S.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  10. Discovery of Eight ASAS-SN Supernovae

    Science.gov (United States)

    Stone, G.; Brimacombe, J.; Cacella, P.; Farfan, R. G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Trappett, D.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  11. Discovery of Four ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Kiyota, S.; Cruz, I.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  12. Discovery of Nine ASAS-SN Supernovae

    Science.gov (United States)

    Cacella, P.; Brimacombe, J.; Fernandez, J. M.; Kiyota, S.; Krannich, G.; Koff, R. A.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Aslan, L.; Bock, G.; Stone, G.

    2018-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  13. Discovery of Five ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  14. Thermoelectric properties of SnSe compound

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Xinhong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Wu, Liyuan; Han, Lihong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Liu, Gang [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Song, Yuxin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2015-09-15

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data.

  15. Thermoelectric properties of SnSe compound

    International Nuclear Information System (INIS)

    Guan, Xinhong; Lu, Pengfei; Wu, Liyuan; Han, Lihong; Liu, Gang; Song, Yuxin; Wang, Shumin

    2015-01-01

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data

  16. New nuclear structure data beyond 136Sn

    Directory of Open Access Journals (Sweden)

    Lozeva Radomira

    2018-01-01

    Full Text Available Exotic nuclei beyond the 132Sn double shell-closure are influenced by both the Sn superfluity and the evolving collectivity only few nucleons away. Toward even more neutron-rich nuclei, especially at intermediate mass number, the interplay between single-particle and collective particle-hole excitations competes. In some cases with the extreme addition of neutrons also other effects as the formation of neutron skin, stabilization as sub-shell gaps or orbital crossings may be expected. The knowledge of nuclear ingredients is especially interesting beyond 132Sn and little is known on how the excitation modes develop with the addition of both protons and neutrons and for example systematic prompt and decay studies can be such very sensitive probe. Recently, we have approached this region of nuclei in several experimental measurements following 238U projectile fission on 9Be and n-induced fission on 241Pu and 235U. Consistent data analysis allows to access various spins and excitation energies and provide new input to theory. Examples from these studies on several nuclei in the A~140 region were presented during the conference together with the possible interpretation of the new data. Here, we will illustrate one example on 136I using two complementary data sets.

  17. New nuclear structure data beyond 136Sn

    Science.gov (United States)

    Lozeva, Radomira

    2018-05-01

    Exotic nuclei beyond the 132Sn double shell-closure are influenced by both the Sn superfluity and the evolving collectivity only few nucleons away. Toward even more neutron-rich nuclei, especially at intermediate mass number, the interplay between single-particle and collective particle-hole excitations competes. In some cases with the extreme addition of neutrons also other effects as the formation of neutron skin, stabilization as sub-shell gaps or orbital crossings may be expected. The knowledge of nuclear ingredients is especially interesting beyond 132Sn and little is known on how the excitation modes develop with the addition of both protons and neutrons and for example systematic prompt and decay studies can be such very sensitive probe. Recently, we have approached this region of nuclei in several experimental measurements following 238U projectile fission on 9Be and n-induced fission on 241Pu and 235U. Consistent data analysis allows to access various spins and excitation energies and provide new input to theory. Examples from these studies on several nuclei in the A 140 region were presented during the conference together with the possible interpretation of the new data. Here, we will illustrate one example on 136I using two complementary data sets.

  18. VERY LATE PHOTOMETRY OF SN 2011fe

    International Nuclear Information System (INIS)

    Kerzendorf, W. E.; Taubenberger, S.; Seitenzahl, I. R.; Ruiter, A. J.

    2014-01-01

    The Type Ia supernova SN 2011fe is one of the closest supernovae of the past decades. Due to its proximity and low dust extinction, this object provides a very rare opportunity to study the extremely late time evolution (>900 days) of thermonuclear supernovae. In this Letter, we present our photometric data of SN 2011fe taken at an unprecedented late epoch of ≈930 days with GMOS-N mounted on the Gemini North telescope (g = 23.43 ± 0.28, r = 24.14 ± 0.14, i = 23.91 ± 0.18, and z = 23.90 ± 0.17) to study the energy production and retention in the ejecta of SN 2011fe. Together with previous measurements by other groups, our result suggests that the optical supernova light curve can still be explained by the full thermalization of the decay positrons of 56 Co. This is in spite of theoretical predicted effects (e.g., infrared catastrophe, positron escape, and dust) that advocate a substantial energy redistribution and/or loss via various processes that result in a more rapid dimming at these very late epochs

  19. A facile inexpensive route for SnS thin film solar cells with SnS{sub 2} buffer

    Energy Technology Data Exchange (ETDEWEB)

    Gedi, Sreedevi [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Minna Reddy, Vasudeva Reddy, E-mail: drmvasudr9@gmail.com [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Pejjai, Babu [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Jeon, Chan-Wook [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Park, Chinho, E-mail: chpark@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Ramakrishna Reddy, K.T., E-mail: ktrkreddy@gmail.com [Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India)

    2016-05-30

    Graphical abstract: PYS spectra of SnS/SnS{sub 2} interface and the related band diagram. - Highlights: • A low cost SnS solar cell is developed using chemical bath deposition. • We found E{sub I} & χ of SnS (5.3 eV & 4.0 eV) and SnS{sub 2} (6.9 eV & 4.1 eV) films from PYS. • Band offsets of 0.1 eV (E{sub c}) and 1.6 eV (E{sub v}) are estimated for SnS/SnS{sub 2} junction. • SnS based solar cell showed a conversion efficiency of 0.51%. - Abstract: Environment-friendly SnS based thin film solar cells with SnS{sub 2} as buffer layer were successfully fabricated from a facile inexpensive route, chemical bath deposition (CBD). Layer studies revealed that as-grown SnS and SnS{sub 2} films were polycrystalline; (1 1 1)/(0 0 1) peaks as the preferred orientation; 1.3 eV/2.8 eV as optical band gaps; and showed homogeneous microstructure with densely packed grains respectively. Ionization energy and electron affinity values were found by applying photoemission yield spectroscopy (PYS) to the CBD deposited SnS and SnS{sub 2} films for the first time. These values obtained as 5.3 eV and 4.0 eV for SnS films; 6.9 eV and 4.1 eV for SnS{sub 2} films. The band alignment of SnS/SnS{sub 2} junction showed TYPE-II heterostructure. The estimated conduction and valance band offsets were 0.1 eV and 1.6 eV respectively. The current density–voltage (J–V) measurements of the cell showed open circuit voltage (V{sub oc}) of 0.12 V, short circuit current density (J{sub sc}) of 10.87 mA cm{sup −2}, fill factor (FF) of 39% and conversion efficiency of 0.51%.

  20. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Science.gov (United States)

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

    2004-10-01

    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  1. Hierarchical Graphene-Encapsulated Hollow SnO2@SnS2 Nanostructures with Enhanced Lithium Storage Capability.

    Science.gov (United States)

    Xu, Wangwang; Xie, Zhiqiang; Cui, Xiaodan; Zhao, Kangning; Zhang, Lei; Dietrich, Grant; Dooley, Kerry M; Wang, Ying

    2015-10-14

    Complex hierarchical structures have received tremendous attention due to their superior properties over their constitute components. In this study, hierarchical graphene-encapsulated hollow SnO2@SnS2 nanostructures are successfully prepared by in situ sulfuration on the backbones of hollow SnO2 spheres via a simple hydrothermal method followed by a solvothermal surface modification. The as-prepared hierarchical SnO2@SnS2@rGO nanocomposite can be used as anode material in lithium ion batteries, exhibiting excellent cyclability with a capacity of 583 mAh/g after 100 electrochemical cycles at a specific current of 200 mA/g. This material shows a very low capacity fading of only 0.273% per cycle from the second to the 100th cycle, lower than the capacity degradation of bare SnO2 hollow spheres (0.830%) and single SnS2 nanosheets (0.393%). Even after being cycled at a range of specific currents varied from 100 mA/g to 2000 mA/g, hierarchical SnO2@SnS2@rGO nanocomposites maintain a reversible capacity of 664 mAh/g, which is much higher than single SnS2 nanosheets (374 mAh/g) and bare SnO2 hollow spheres (177 mAh/g). Such significantly improved electrochemical performance can be attributed to the unique hierarchical hollow structure, which not only effectively alleviates the stress resulting from the lithiation/delithiation process and maintaining structural stability during cycling but also reduces aggregation and facilitates ion transport. This work thus demonstrates the great potential of hierarchical SnO2@SnS2@rGO nanocomposites for applications as a high-performance anode material in next-generation lithium ion battery technology.

  2. Changes of electronic structure of SnTe due to high concentration of Sn vacancies

    International Nuclear Information System (INIS)

    Masek, J.; Nuzhnyj, D.N.

    1997-01-01

    Non-stoichiometric Sn 1-y Te is a strongly degenerated n-type semiconductor. This is important for understanding unusual features of magnetic behaviour of Sn 1-x Gd x Te where the relative positions of the Fermi energy and the atomic d-level of Gd govern the exchange coupling.The influence of the Sn vacancies on the band structure cannot be neglect if their concentration reaches a few atomic percent. We address this problem by using a tight-binding coherent potential approach and show that although the character of the bands remains unchanged, they are modified so that ε d can come out above the heavy-hole band. (author)

  3. 0(gs)+ -->2(1)+ transition strengths in 106Sn and 108Sn.

    Science.gov (United States)

    Ekström, A; Cederkäll, J; Fahlander, C; Hjorth-Jensen, M; Ames, F; Butler, P A; Davinson, T; Eberth, J; Fincke, F; Görgen, A; Górska, M; Habs, D; Hurst, A M; Huyse, M; Ivanov, O; Iwanicki, J; Kester, O; Köster, U; Marsh, B A; Mierzejewski, J; Reiter, P; Scheit, H; Schwalm, D; Siem, S; Sletten, G; Stefanescu, I; Tveten, G M; Van de Walle, J; Van Duppen, P; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Zielińska, M

    2008-07-04

    The reduced transition probabilities, B(E2; 0(gs)+ -->2(1)+), have been measured in the radioactive isotopes (108,106)Sn using subbarrier Coulomb excitation at the REX-ISOLDE facility at CERN. Deexcitation gamma rays were detected by the highly segmented MINIBALL Ge-detector array. The results, B(E2;0(gs)+ -->2(1)+)=0.222(19)e2b2 for 108Sn and B(E2; 0(gs)+-->2(1)+)=0.195(39)e2b2 for 106Sn were determined relative to a stable 58Ni target. The resulting B(E2) values are approximately 30% larger than shell-model predictions and deviate from the generalized seniority model. This experimental result may point towards a weakening of the N=Z=50 shell closure.

  4. XRF 100316D/SN 2010bh and the nature of gamma-ray burst supernovae

    NARCIS (Netherlands)

    Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Levan, A.J.; Tanvir, N.R.; Wiersema, K.; D'Avanzo, P.; Fruchter, A.S.; Garnavich, P.; Gomboc, A.; Gorosabel, J.; Kasen, D.; Kopač, D.; Margutti, R.; Mazzali, P.A.; Melandri, A.; Mundell, C.G.; Nugent, P.E.; Pian, E.; Smith, R.J.; Steele, I.; Wijers, R.A.M.J.; Woosley, S.E.

    2011-01-01

    We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN

  5. Superconductivity optimization and phase formation kinetics study of internal-Sn Nb3Sn superconducting wires

    International Nuclear Information System (INIS)

    Zhang, Chaowu

    2007-07-01

    Superconductors Nb 3 Sn wires are one of the most applicable cryogenic superconducting materials and the best choice for high-field magnets exceeding 10 T. One of the most significant utilization is the ITER project which is regarded as the hope of future energy source. The high-Cu composite designs with smaller number of sub-element and non-reactive diffusion barrier, and the RRP (Restacked Rod Process) internal-Sn technology are usually applied for the wire manufacturing. Such designed and processed wires were supplied by MSA/Alstom and WST/NIN in this research. The systematic investigation on internal-Sn superconducting wires includes the optimization of heat treatment (HT) conditions, phase formation and its relation with superconductivity, microstructure analysis, and the phase formation kinetics. Because of the anfractuosity of the configuration design and metallurgical processing, the MF wires are not sufficient for studying a sole factor effect on superconductivity. Therefore, four sets of mono-element (ME) wires with different Sn ratios and different third-element addition were designed and fabricated in order to explore the relationship between phase formation and superconducting performances, particularly the A15 layer growth kinetics. Different characterization technic have been used (magnetization measurements, neutron diffraction and SEM/TEM/EDX analysis). The A15 layer thicknesses of various ME samples were measured and carried out linear and non-linear fits by means of two model equations. The results have clearly demonstrated that the phase formation kinetics of Nb 3 Sn solid-state reaction is in accordance with an n power relation and the n value is increased with the increase of HT temperature and the Sn ratio in the wire composite. (author)

  6. Premaximum observations of the type Ia SN 1990N

    International Nuclear Information System (INIS)

    Leibundgut, B.; Kirshner, R.P.; Filippenko, A.V.; Shields, J.C.; Foltz, C.B.; Phillips, M.M.; Sonneborn, G.

    1991-01-01

    Spectroscopic and photometric observations of SN 1990N were obtained at ultraviolet and optical wavelengths, beginning 14 days before maximum light. The early observations reveal important differences from spectra of SN Ia's around maximum light. Photometry and spectroscopy obtained after maximum show that SN 1990N is a typical SN Ia and that most of the observed differences are due to the early epoch of the observations. The most significant characteristics are (1) the high velocities of Ca and Si up to 22,000 km/s; (2) the presence of Co and Fe 2 weeks before maximum; and (3) the more rapid increase in the UV flux compared to the optical. The most popular models for white dwarf deflagration that have provided the standard interpretation for SN Ia's at maximum light do not reproduce the high velocities of Ca II and Si II lines observed in SN 1990N. 37 refs

  7. Development of a 117mSn preparation method

    International Nuclear Information System (INIS)

    Moraes, Vanessa; Osso Junior, Joao Alberto

    2000-01-01

    117m Sn is a radioisotope with suitable characteristics to be used in nuclear medicine as radiotherapy, when labeled with DTPA. The aim of this work is the preparation of 117m Sn from irradiation of the natural tin with proton beam at the cyclotron CV-28 of IPEN-CNEN/SP via the nuclear reaction nat Sn (p, xn) 117 Sb to 117m Sn. Due to the formation of the Sb precursor it is necessary to perform a chemical separation for Sb-Sn. The separation method used was the ion exchange, due to its utilization facilities for radioactive material. Chemical, radiochemical and radionuclidic methods were also developed for the quality control of the final product, the 117m Sn. (author)

  8. Tunneling spectroscopy on superconducting Nb3Sn with artioficial barriers

    International Nuclear Information System (INIS)

    Schneider, U.

    1984-03-01

    Tunneling diodes on Nb 3 Sn were prepared by magnetron sputtering. The superconducting transition temperatures of the Nb 3 Sn films were in the range of 5 to 18 K. An energetically low-lying structure in the tunneling density of states has been localized by detailed studies of the second derivative of the current-voltage characteristics of the diodes. This structure was found near 5.5 meV for stoichiometric Nb 3 Sn (Tsub(c) approx.= 18 K) and at 6.7 meV for understoichiometric Nb 3 Sn (Tsub(c) approx.= 5 K). The minimum in the conductance at zero energy found in the normal state could be identified to be mainly due to inelastic phonon processes of barrier phonons and Nb 3 Sn phonons. Deformations were found in the tunneling density of states of stoichiometric Nb 3 Sn diodes which lead to contradiction when explained by proximity effects. (orig./GSCH)

  9. Surface alloying in Sn/Au(111) at elevated temperature

    Science.gov (United States)

    Sadhukhan, Pampa; Singh, Vipin Kumar; Rai, Abhishek; Bhattacharya, Kuntala; Barman, Sudipta Roy

    2018-04-01

    On the basis of x-ray photoelectron spectroscopy, we show that when Sn is deposited on Au(111) single crystal surface at a substrate temperature TS=373 K, surface alloying occurs with the formation of AuSn phase. The evolution of the surface structure and the surface morphology has been studied by low energy electron diffraction and scanning tunneling microscopy, respectively as a function of Sn coverage and substrate temperatures.

  10. Structural properties and hyperfine characterization of Sn-substituted goethites

    Energy Technology Data Exchange (ETDEWEB)

    Larralde, A.L. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Ramos, C.P. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Arcondo, B. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850 (C1063ACV), Bs. As. (Argentina); Tufo, A.E. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Saragovi, C. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Sileo, E.E., E-mail: sileo@qi.fcen.uba.ar [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Pure and tin-doped goethites were synthesized from Sn(II) solutions at ambient pressure and 70 Degree-Sign C. Black-Right-Pointing-Pointer The Rietveld refinement of PXRD data indicated that Sn partially substituted the Fe(III) ions. Black-Right-Pointing-Pointer The substitution provoked unit cell expansion, and a distortion of the coordination polyhedron. Black-Right-Pointing-Pointer {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV). Black-Right-Pointing-Pointer {sup 57}Fe Moessbauer spectroscopy showed a lower magnetic coupling as tin concentration increased. - Abstract: Tin-doped goethites obtained by a simple method at ambient pressure and 70 Degree-Sign C were characterized by inductively coupled plasma atomic emission spectrometry, scanning electron microscopy, Rietveld refinement of powder X-ray diffraction data, and {sup 57}Fe and {sup 119}Sn Moessbauer spectroscopy. The particles size and the length to width ratios decreased with tin-doping. Sn partially substituted the Fe(III) ions provoking unit cell expansion and increasing the crystallinity of the particles with enlarged domains that grow in the perpendicular and parallel directions to the anisotropic broadening (1 1 1) axis. Intermetallic E, E Prime and DC distances also change although the variations are not monotonous, indicating different variations in the coordination polyhedron. In general, the Sn-substituted samples present larger intermetallic distances than pure goethite, and the greatest change is shown in the E Prime distance which coincides with the c-parameter. {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV) in the samples. On the other hand, Fe(II) presence was not detected by {sup 57}Fe Moessbauer spectroscopy, suggesting the existence of vacancies in the Sn-doped samples. A lower magnetic coupling is also evidenced from the average magnetic hyperfine field values obtained as tin

  11. Fabrication of high crystalline SnS and SnS2 thin films, and their switching device characteristics

    Science.gov (United States)

    Choi, Hyeongsu; Lee, Jeongsu; Shin, Seokyoon; Lee, Juhyun; Lee, Seungjin; Park, Hyunwoo; Kwon, Sejin; Lee, Namgue; Bang, Minwook; Lee, Seung-Beck; Jeon, Hyeongtag

    2018-05-01

    Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS2) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS2 thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS2 thin film by annealing at 450 °C for 1 h in H2S atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS2 thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 105 and 104 cm‑1 in the visible region, respectively. In addition, SnS and SnS2 thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS2 directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS2 thin films exhibited on–off drain current ratios of 8.8 and 2.1 × 103 and mobilities of 0.21 and 0.014 cm2 V‑1 s‑1, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS2 thin films were 6.0 × 1016 and 8.7 × 1013 cm‑3, respectively, in this experiment.

  12. Phase Equilibria of Sn-Co-Cu Ternary System

    Science.gov (United States)

    Chen, Yu-Kai; Hsu, Chia-Ming; Chen, Sinn-Wen; Chen, Chih-Ming; Huang, Yu-Chih

    2012-10-01

    Sn-Co-Cu ternary alloys are promising lead-free solders, and isothermal sections of Sn-Co-Cu phase equilibria are fundamentally important for the alloys' development and applications. Sn-Co-Cu ternary alloys were prepared and equilibrated at 523 K, 1073 K, and 1273 K (250 °C, 800 °C, and 1000 °C), and the equilibrium phases were experimentally determined. In addition to the terminal solid solutions and binary intermetallic compounds, a new ternary compound, Sn3Co2Cu8, was found. The solubilities of Cu in the α-CoSn3 and CoSn2 phases at 523 K (250 °C) are 4.2 and 1.6 at. pct, respectively, while the Cu solubility in the α-Co3Sn2 phase is as high as 20.0 at. pct. The Cu solubility increases with temperature and is around 30.0 at. pct in the β-Co3Sn2 at 1073 K (800 °C). The Co solubility in the η-Cu6Sn5 phase is also significant and is 15.5 at. pct at 523 K (250 °C).

  13. The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

    Energy Technology Data Exchange (ETDEWEB)

    Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2008-02-15

    The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

  14. The 20th anniversary of SN1987A

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, A [KEK, High Energy Accelerator Research Organization, Oho 1-1, Tsukuba, Ibaragi, 305-0801 (Japan)], E-mail: atsuto.suzuki@kek.jp

    2008-07-15

    Observation of a neutrino burst from the supernova, SN1987A opened a new window of observational astronomy by neutrinos. And the history showed that the SN1987A neutrino burst observation was the vanguard of successive discoveries of neutrino properties by Super-Kamiokande, SNO, K2K, KamLAND and so on. On the occasion of the SN1987A 20th anniversary, the backstage story up to the discovery of the SN1987A neutrino bursts is summarized, tracing the Kamiokande log-note and including the IMB, LSD and Baksan data.

  15. Phase diagram of the ternary Zr-Ti-Sn system

    International Nuclear Information System (INIS)

    Arias, D.; Gonzalez Camus, M.

    1987-01-01

    It is well known that Ti stabilizes the high temperature cubic phase of Zr and that Sn stabilizes the low temperature hexagonal phase of Zr. The effect of Sn on the Zr-Ti diagram has been studied in the present paper. Using high purity metals, nine different alloys have been prepared, with 4-32 at % Ti, 0.7-2.2 at % Sn and Zr till 100%. Resistivity and optical and SEM metallography techniques have been employed. Effect of some impurities have been analyzed. The results are discussed and different isothermic sections of the ternary Zr-Ti-Sn diagram are presented. (Author) [es

  16. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    International Nuclear Information System (INIS)

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V.

    2009-01-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO 2 phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  17. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V., E-mail: dfsilva@ipen.b, E-mail: espinace@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO{sub 2} phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  18. Production of superconducting Nb3Sn wire using Nb or Nb(Ti) and Sn(Ga) solid solution powders

    International Nuclear Information System (INIS)

    Thieme, C.L.H.; Foner, S.

    1991-01-01

    This paper reports on superconducting Nb 3 Sn wire produced by the powder metallurgy method using Nb or Nb-2.9 at% Ti powder in combination with Sn-x at% Ga powders (x = 3, 4.2, 6.2 and 9.0). Ga additions to the Sn caused considerable solid solution hardening which improved its workability. It made the Nb-Sn(Ga) powder combinations convenient for swaging and extensive wire drawing. Anneals at 950 degrees C produced wires with an overall J c of 10 4 A/cm 2 at 21.9 T for wires with both Ti in the Nb and 6.2 at% Ga in the Sn. Comparison of this wire with the best Nb(Ti)-Cu-internal Sn(Ti) shows a higher J c per A15 areas, especially in fields of 22T and above

  19. Electrochemical properties of Ti-Ni-Sn materials predicted by {sup 119}Sn Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ladam, A., E-mail: alix.ladam@univ-montp2.fr; Aldon, L.; Lippens, P.-E.; Olivier-Fourcade, J.; Jumas, J.-C. [Université de Montpellier, Institut Charles Gerhardt, UMR 5253 CNRS (France); Cenac-Morthe, C. [CNES, Service DCT/TV/El (France)

    2016-12-15

    The electrochemical activity of TiNiSn, TiNi {sub 2}Sn and Ti {sub 6}Sn {sub 5} compounds considered as negative electrode materials for Li-ion batteries has been predicted from the isomer shift- Hume-Rothery electronic density correlation diagram. The ternary compounds were obtained from solid-state reactions and Ti {sub 6}Sn {sub 5} by ball milling. The {sup 119}Sn Mössbauer parameters were experimentally determined and used to evaluate the Hume-Rothery electronic density [e {sub av}]. The values of [e {sub av}] are in the region of Li-rich Li-Sn alloys for Ti {sub 6}Sn {sub 5} and outside this region for the ternary compounds, suggesting that the former compound is electrochemically active but not the two latter ones. Electrochemical tests were performed for these different materials confirming this prediction. The close values of [e {sub av}] for Ti {sub 6}Sn {sub 5} and Li-rich Li-Sn alloys indicate that the observed good capacity retention could be related to small changes in the global structures during cycling.

  20. Temperature varying photoconductivity of GeSn alloys grown by chemical vapor deposition with Sn concentrations from 4% to 11%

    Science.gov (United States)

    Hart, John; Adam, Thomas; Kim, Yihwan; Huang, Yi-Chiau; Reznicek, Alexander; Hazbun, Ramsey; Gupta, Jay; Kolodzey, James

    2016-03-01

    Pseudomorphic GeSn layers with Sn atomic percentages between 4.5% and 11.3% were grown by chemical vapor deposition using digermane and SnCl4 precursors on Ge virtual substrates grown on Si. The layers were characterized by x-ray diffraction rocking curves and reciprocal space maps. Photoconductive devices were fabricated, and the dark current was found to increase with Sn concentration. The responsivity of the photoconductors was measured at a wavelength of 1.55 μm using calibrated laser illumination at room temperature and a maximum value of 2.7 mA/W was measured for a 4.5% Sn device. Moreover, the responsivity for higher Sn concentration was found to increase with decreasing temperature. Spectral photoconductivity was measured using Fourier transform infrared spectroscopy. The photoconductive absorption edge continually increased in wavelength with increasing tin percentage, out to approximately 2.4 μm for an 11.3% Sn device. The direct band gap was extracted using Tauc plots and was fit to a bandgap model accounting for layer strain and Sn concentration. This direct bandgap was attributed to absorption from the heavy-hole band to the conduction band. Higher energy absorption was also observed, which was thought to be likely from absorption in the light-hole band. The band gaps for these alloys were plotted as a function of temperature. These experiments show the promise of GeSn alloys for CMOS compatible short wave infrared detectors.

  1. Microstructural investigation and SnO nanodefects in spray-pyrolyzed SnO2 thin films

    DEFF Research Database (Denmark)

    Thanachayanont, Chanchana; Yordsri, Visittapong; Boothroyd, Chris

    2011-01-01

    Spray pyrolysis is one of the most cost-effective methods to prepare SnO2 films due to its ability to deposit large uniform area, low fabrication cost, simplicity and low deposition temperature. Conventionally, scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) are routinely used...... diffraction (CBED). It was found that large grain-size vertically-aligned columnar SnO2 grains were formed after a few layers of small grain-size randomly oriented SnO2 grains. Moreover, CBED showed the presence of SnO nanodefects that had not been reported before and could not be detected by SEM or XRD....

  2. Fluid-sensitive nanoscale switching with quantum levitation controlled by α -Sn/β -Sn phase transition

    Science.gov (United States)

    Boström, Mathias; Dou, Maofeng; Malyi, Oleksandr I.; Parashar, Prachi; Parsons, Drew F.; Brevik, Iver; Persson, Clas

    2018-03-01

    We analyze the Lifshitz pressure between silica and tin separated by a liquid mixture of bromobenzene and chlorobenzene. We show that the phase transition from semimetallic α -Sn to metallic β -Sn can switch Lifshitz forces from repulsive to attractive. This effect is caused by the difference in dielectric functions of α -Sn and β -Sn , giving both attractive and repulsive contributions to the total Lifshitz pressure in different frequency regions controlled by the composition of the intervening liquid mixture. In this way, one may be able to produce phase-transition-controlled quantum levitation in a liquid medium.

  3. Interfacial Bonding Energy on the Interface between ZChSnSb/Sn Alloy Layer and Steel Body at Microscale

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2017-09-01

    Full Text Available To investigate the performance of bonding on the interface between ZChSnSb/Sn and steel body, the interfacial bonding energy on the interface of a ZChSnSb/Sn alloy layer and the steel body with or without Sn as an intermediate layer was calculated under the same loadcase using the molecular dynamics simulation software Materials Studio by ACCELRYS, and the interfacial bonding energy under different Babbitt thicknesses was compared. The results show that the bonding energy of the interface with Sn as an intermediate layer is 10% larger than that of the interface without a Sn layer. The interfacial bonding performances of Babbitt and the steel body with Sn as an intermediate layer are better than those of an interface without a Sn layer. When the thickness of the Babbitt layer of bushing is 17.143 Å, the interfacial bonding energy reaches the maximum, and the interfacial bonding performance is optimum. These findings illustrate the bonding mechanism of the interfacial structure from the molecular level so as to ensure the good bonding properties of the interface, which provides a reference for the improvement of the bush manufacturing process from the microscopic point of view.

  4. Interfacial Bonding Energy on the Interface between ZChSnSb/Sn Alloy Layer and Steel Body at Microscale.

    Science.gov (United States)

    Wang, Jianmei; Xia, Quanzhi; Ma, Yang; Meng, Fanning; Liang, Yinan; Li, Zhixiong

    2017-09-25

    To investigate the performance of bonding on the interface between ZChSnSb/Sn and steel body, the interfacial bonding energy on the interface of a ZChSnSb/Sn alloy layer and the steel body with or without Sn as an intermediate layer was calculated under the same loadcase using the molecular dynamics simulation software Materials Studio by ACCELRYS, and the interfacial bonding energy under different Babbitt thicknesses was compared. The results show that the bonding energy of the interface with Sn as an intermediate layer is 10% larger than that of the interface without a Sn layer. The interfacial bonding performances of Babbitt and the steel body with Sn as an intermediate layer are better than those of an interface without a Sn layer. When the thickness of the Babbitt layer of bushing is 17.143 Å, the interfacial bonding energy reaches the maximum, and the interfacial bonding performance is optimum. These findings illustrate the bonding mechanism of the interfacial structure from the molecular level so as to ensure the good bonding properties of the interface, which provides a reference for the improvement of the bush manufacturing process from the microscopic point of view.

  5. Phase Equilibria in the Sn-Rich Corner of the Ni-Sb-Sn System

    Czech Academy of Sciences Publication Activity Database

    Mishra, R.; Kroupa, Aleš; Zemanová, Adéla; Ipser, H.

    2013-01-01

    Roč. 42, č. 4 (2013), s. 646-653 ISSN 0361-5235 Institutional support: RVO:68081723 Keywords : lead-free solder * high-temperature solder * Ni-Sb-Sn system Subject RIV: BJ - Thermodynamics Impact factor: 1.675, year: 2013

  6. `Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31

    Directory of Open Access Journals (Sweden)

    Wilhelm Klein

    2015-07-01

    Full Text Available The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarah et al. (1981. Z. Metallkd, 72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3:0.62 (3. One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b.

  7. Phase formation in Mg-Sn-Si and Mg-Sn-Si-Ca alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, A.; Groebner, J. [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Schmid-Fetzer, R., E-mail: schmid-fetzer@tu-clausthal.de [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany)

    2011-02-17

    Research highlights: > The solidification paths of ternary and quaternary alloys are analyzed in detail, using the tool of thermodynamic calculations. > The precipitation sequence of phases and their amounts compare well with the microstructure of alloys. > The most efficient comparison to the experimental thermal analysis data is done by calculation of the enthalpy variation with temperature. > The viability of a procedure for the selection of multicomponent key samples is demonstrated for the development of the Mg-Ca-Si-Sn phase diagram. - Abstract: Experimental work is done and combined with the Calphad method to generate a consistent thermodynamic description of the Mg-Ca-Si-Sn quaternary system, validated for Mg-rich alloys. The viability of a procedure for the selection of multicomponent key samples is demonstrated for this multicomponent system. Dedicated thermal analysis with DTA/DSC on sealed samples is performed and the microstructure of slowly solidified alloys is analyzed using SEM/EDX. The thermodynamic description and phase diagram of the ternary Mg-Si-Sn system, developed in detail also in this work, deviates significantly from a previous literature proposal. The phase formation in ternary and quaternary alloys is analyzed using the tool of thermodynamic equilibrium and Scheil calculations for the solidification paths and compared with present experimental data. The significant ternary/quaternary solid solubilities of pertinent intermetallic phases are quantitatively introduced in the quaternary Mg-Ca-Si-Sn phase diagram and validated by experimental data.

  8. The converged Sn algorithm for nuclear criticality

    International Nuclear Information System (INIS)

    Ganapol, B. D.; Hadad, K.

    2009-01-01

    A new discrete ordinates algorithm to determine the multiplication factor of a 1D nuclear reactor, based on Bengt Carlson's S n method, is presented. The algorithm applies the Romberg and Wynn-epsilon accelerators to accelerate a 1D, one-group S n solution to its asymptotic limit. We demonstrate the feasibility of the Converged Sn (CSn) solution on several one-group criticality benchmark compilations. The new formulation is especially convenient since it enables highly accurate critical fluxes and eigenvalues using the most fundamental transport algorithm. (authors)

  9. Asymmetry of the SN 1987A envelope

    International Nuclear Information System (INIS)

    Chugaj, N.N.

    1991-01-01

    The origin of the peculiar structure in the profiles of the emission lines observed in the spectrum of SN 1987A, namely, (1) redshift of maxima, and (2) fine structure of hydrogen lines, is considered. Among the three proposed hypothesis for the redshift, at least two (electron scattering in the spherically-symmetric envelope, and geometrical effects in the fragmented envelope) have serious drawbacks. More favorable is the third hypothesis which invokes asymmetric distribution of 56 Ni and of the iron-peak elements

  10. Recent results on SN 1987A

    International Nuclear Information System (INIS)

    Woosley, S.E.; Pinto, P.A.; Weaver, T.A.

    1988-01-01

    Several critical issues recently raised by observations of SN 1987A are addressed. These include: the evolution of the pre-supernova star, why it was blue, what its composition and core structure were; the detailed isotopic composition of the ejecta; why and to what extent the supernova composition was mixed in velocity space; the interpretation of recently observed infrared lines, especially their profiles and the existence of red-shifted 'wings'; and what has become of the neutron star. 64 refs., 14 figs., 1 tab

  11. The NASA SN1987A program

    International Nuclear Information System (INIS)

    Teegarden, B.J.

    1988-01-01

    The existing and planned experiments for making gamma-ray observations of SN1987A are reviewed. The main emphasis is on the NASA program which consists primarily of balloon-borne instruments. Some 11--13 experiments are or will be available. Four have already flown from Alice Springs, Australia with null results. Campaigns are planned on nominal six month centers with more possible if gamma-rays are detected. In addition long duration flights from Australia to South America are planned for January 88 and 89

  12. Oxidation and reduction kinetics of eutectic SnPb, InSn, and AuSn: a knowledge base for fluxless solder bonding applications

    DEFF Research Database (Denmark)

    Kuhmann, Jochen Friedrich; Preuss, A.; Adolphi, B.

    1998-01-01

    : (1) SnPb; (2) InSn; (3) AuSn. The studies of the oxidation kinetics show that the growth of the native oxide, which covers the solder surfaces from the start of all soldering operations is self-limiting. The rate of oxidation on the molten, metallic solder surfaces is significantly reduced...... and reduction kinetics, are applied to flip-chip (FC) bonding experiments in vacuum with and without the injection of H2. Wetting in vacuum is excellent but the self-alignment during flip-chip soldering is restricted. The desired, perfectly self-aligned FC-bonds have been only achieved, using evaporated...

  13. Phase Equilibria of the Ternary Sn-Pb-Co System at 250°C and Interfacial Reactions of Co with Sn-Pb Alloys

    Science.gov (United States)

    Wang, Chao-hong; Kuo, Chun-yi; Yang, Nian-cih

    2015-11-01

    The isothermal section of the ternary Sn-Pb-Co system at 250°C was experimentally determined through a series of the equilibrated Sn-Pb-Co alloys of various compositions. The equilibrium phases were identified on the basis of compositional analysis. For the Sn-Co intermetallic compounds (IMCs), CoSn3, CoSn2, CoSn and Co3Sn2, the Pb solubility was very limited. There exist five tie-triangle regions. The Co-Pb system involves one monotectic reaction, so the phase separation of liquid alloys near the Co-Pb side occurred prior to solidification. The immiscibility field was also determined. Additionally, interfacial reactions between Co and Sn-Pb alloys were conducted. The reaction phase for the Sn-48 at.%Pb and Sn-58 at.%Pb at 250°C was CoSn3 and CoSn2, respectively. Both of them were simultaneously formed in the Sn-53 at.%Pb/Co. The formed IMCs were closely associated to the phase equilibria relationship of the liquid-CoSn3-CoSn2 tie-triangle. Furthermore, with increasing temperatures, the phase formed in equilibrium with Sn-37 wt.%Pb was found to transit from CoSn3 to CoSn2 at 275°C. We propose a simple method of examining the phase transition temperature in the interfacial reactions to determine the boundaries of the liquid-CoSn3-CoSn2 tie-triangles at different temperatures.

  14. Phase analysis of superconducting Nb-Sn materials by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sitek, J.; Tomasich, M.; Cirak, J.; Prejsa, M.; Kruzliak, J.

    1978-01-01

    Moessbauer spectroscopy is used for the optimalization of superconducting Nb-Sn samples preparation in the form of foils. Pure phases of Nb 3 Sn, Nb 6 Sn 5 , and NbSn 2 are determined. Two series of samples are studied at 750 and 900 0 C tinning temperature respectively, and at 750, 860, 900, and 960 0 C heating temperatures. In the samples the phases Nb 3 Sn, Nb 6 Sn 5 , NbSn 2 , and the solid solution Nb-Sn phase are observed. The results from the phase analysis lead to the assumption that the percentage amount of the phases is preferentially dependent on the tinning temperature. (author)

  15. Neutron emission spectra of excited 126–140Sn nuclei

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Rajasekaran, M.

    2004-01-01

    We investigate one-neutron and two-neutron emission from 132 Sn and its neighboring isotopes due to thermal excitation. The rotational states of 132 Sn at different temperatures are investigated. The effects of separation energy and thermal excitation energy on neutron emission probability are studied. (author)

  16. Distinction between SnO2 nanoparticles synthesized using co ...

    Indian Academy of Sciences (India)

    Administrator

    pared with that of a co-precipitation-modified SnO2 nanoparticles. Keywords. SnO2 nanoparticle ... Dye-sensitized solar cells (DSSCs), which convert light to electricity by means of ... nature, additives and aging time. Nanosized particles pre-.

  17. Moderation of the 119mSn isomer radioactive decay

    International Nuclear Information System (INIS)

    Godovikov, S.K.

    1999-01-01

    The evaluation of the constant of the braked 119m Sn nuclei decay in the Moessbauer source, being for a long time in contact with a resonance shield, is carried out. The high stability of these nuclei relative to decay is established. The 119m Sn subjected to prolonged impact of the standing electromagnetic wave field become resistant to radioactive decay [ru

  18. The ASAS-SN bright supernova catalogue - III. 2016

    DEFF Research Database (Denmark)

    Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

    2017-01-01

    This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d......This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d...

  19. THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

    International Nuclear Information System (INIS)

    Washabaugh, Pearce C.; Bregman, Joel N.

    2013-01-01

    In globular clusters, dynamical evolution produces luminous X-ray emitting binaries at a rate about 200 times greater than in the field. If globular clusters also produce SN Ia at a high rate, it would account for many of the SN Ia production in early-type galaxies and provide insight into their formation. Here we use archival Hubble Space Telescope (HST) images of nearby galaxies that have hosted an SN Ia to examine the rate at which globular clusters produce these events. The location of the SN Ia is registered on an HST image obtained before the event or after the supernova (SN) faded. Of the 36 nearby galaxies examined, 21 had sufficiently good data to search for globular cluster hosts. None of the 21 SNe have a definite globular cluster counterpart, although there are some ambiguous cases. This places an upper limit to the enhancement rate of SN Ia production in globular clusters of about 42 at the 95% confidence level, which is an order of magnitude lower than the enhancement rate for luminous X-ray binaries. Even if all of the ambiguous cases are considered as having a globular cluster counterpart, the upper bound for the enhancement rate is 82 at the 95% confidence level, still a factor of several below that needed to account for half of the SN Ia events. Barring unforeseen selection effects, we conclude that globular clusters are not responsible for producing a significant fraction of the SN Ia events in early-type galaxies.

  20. Advantage and Challenges of $Nb_3Sn$ Superconducting Undulators

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A. V. [Fermilab; Barzi, E. [Fermilab; Turrinoni, D. [Fermilab; Ivanyushenkov, Yu. [Argonne; Kesgin, I. [Argonne

    2018-04-01

    Utilization of Nb3Sn superconducting wires offers the possibility to increase undulators’ nominal operation field and temperature margin, but requires overcoming chal-lenges that are described in this paper. The achievable field levels for a Nb3Sn version of superconducting undulators being developed at APS-ANL and the conductor choice are also presented and discussed.

  1. Muon spin rotation measurements on LaNiSn

    International Nuclear Information System (INIS)

    Drew, A.J.; Lee, S.L.; Ogrin, F.Y.; Charalambous, D.; Bancroft, N.; Paul, D. McK.; Takabatake, T.; Baines, C.

    2006-01-01

    The first microscopic investigation of superconductivity in LaNiSn is reported using muon spin rotation. LaNiSn is found to be mainly a type I superconductor in an intermediate state with some evidence for type II behaviour at low temperatures, possibly due to a temperature dependent Ginzburg Landau parameter κ

  2. Reference Data for the Density, Viscosity, and Surface Tension of Liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn Eutectic Alloys

    Science.gov (United States)

    Dobosz, Alexandra; Gancarz, Tomasz

    2018-03-01

    The data for the physicochemical properties viscosity, density, and surface tension obtained by different experimental techniques have been analyzed for liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn eutectic alloys. All experimental data sets have been categorized and described by the year of publication, the technique used to obtain the data, the purity of the samples and their compositions, the quoted uncertainty, the number of data in the data set, the form of data, and the temperature range. The proposed standard deviations of liquid eutectic Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn alloys are 0.8%, 0.1%, 0.5%, 0.2%, and 0.1% for the density, 8.7%, 4.1%, 3.6%, 5.1%, and 4.0% for viscosity, and 1.0%, 0.5%, 0.3%, N/A, and 0.4% for surface tension, respectively, at a confidence level of 95%.

  3. Nonlocal Cooper pair splitting in a pSn-junction

    NARCIS (Netherlands)

    Veldhorst, M.; Brinkman, Alexander

    2010-01-01

    Perfect Cooper pair splitting is proposed, based on crossed Andreev reflection (CAR) in a p-type semiconductor-superconductor-n-type semiconductor (pSn) junction. The ideal splitting is caused by the energy filtering that is enforced by the band structure of the electrodes. The pSn junction is

  4. Josephson effects in Nb3Sn microbridges

    International Nuclear Information System (INIS)

    Lee, T.W.; Falco, C.M.

    1981-01-01

    Josephson effects in long narrow Nb/sub 3/Sn microbridges at temperatures up to 17 K were studied. These microbridges are formed by photolithographic techniques and subsequently subjected to controlled electrical discharges to modifY the intrinsic T/sub c/ of the bridge region. The bridges exhibit 10 GHz microwave steps in their I-V characteristics whose amplitudes are in agreement with the Resistively Shunted Junction (RSJ) model. I-V characteristics can be fit assuming an effective temperature approximately 15 K above the bath temperature. Structures in the I-V characteristics in the absence of microwaves were also investigated. It was demonstrated that phase-slip centers are induced at weak superconducting positions along the bridge when the S-N boundarY of an expanding hot spot reaches within a thermal healing distance. The critical current of the phase-slip center thus formed exhibits a temperature dependence (1-T/T/sub c/)/one-half/ insteady of the usual mean field result (1-T/T/sub c/)/sup 3/2/. 12 refs

  5. A Nb3Sn high field dipole

    International Nuclear Information System (INIS)

    McClusky, R.; Robins, K.E.; Sampson, W.B.

    1990-01-01

    A dipole magnet approximately 1 meter long with an 8 cm bore has been fabricated from cable made from Nb 3 Sn multifilamentary strands. The coil consists of four layers of conductor wound in pairs to eliminate internal joints. Each set of layers is separately constrained with Kevlar-epoxy bands and the complete assembly clamped in a split laminated iron yoke. The inner coil pairs were wound before heat treating while the outer coils were formed from pre-reacted cable using conventional insulation. A NbTi version of the magnet was fabricated using SSC version of the magnet was fabricated using SSC conductor to test the construction techniques. This magnet reached a maximum central field of 7.6 Tesla, at 4.4K which is very close to the limit estimated from conductor measurements. The Nb 3 Sn magnet, however, only reached a maximum field at 8.1T considerably short of the field expected from measurements on the inner cable. 7 refs., 5 figs

  6. Synthesis and lithium storage properties of Zn, Co and Mg doped SnO2 Nano materials

    CSIR Research Space (South Africa)

    Palaniyandy, Nithyadharseni

    2017-09-01

    Full Text Available In this paper, we show that magnesium and cobalt doped SnO2 (Mg-SnO2 and Co-SnO2) nanostructures have profound influence on the discharge capacity and coulombic efficiency of lithium ion batteries (LIBs) employing pure SnO2 and zinc doped SnO2 (Zn-Sn...

  7. Hydrodynamical models of supernova SN 1987 A in the LMC

    International Nuclear Information System (INIS)

    Grassberg, E.K.; Imshennik, V.S.; Nadezhin, D.K.; Utrobin, V.P.

    1987-01-01

    It is shown that the properties of SN 1987A in LMC can be described well by hydrodynamical models of explosions of compact massive stars. In accordance with these models, the mass of the expelled envelope the presupernova radius and the total energy of explosion are evaluated for SN 1987A to be ∼ 16M Sun , ∼ 30R Sun , and ∼ 3.10 51 erg, respectively. The progenitor of supernova remnant Cas A may be considered as the prototype to the SN 1987A in our own Galaxy. In other galaxies, this subtype of supernovae can be represented by SN 1948B in NGC6946. If energy of explosion transfers from collapsed core of the star to the envelope within timescale less than 1 hour, then delay Δt ∼ 3 hours between the neutrino pulse and the steep rise of optical luminosity of SN 1987A does not contradict with scenario of explosions of compact massive stars

  8. Dimensional stability of Ti--6Al--6V--2Sn

    International Nuclear Information System (INIS)

    Rack, H.J.

    1978-08-01

    The dimensional stability of Ti-6Al-6V-2Sn has been examined. It is shown that in the duplex annealed condition Ti-6Al-6V-2Sn is dimensionally stable at temperatures up to 448 0 K for 512 hrs. Solution treated Ti-6Al-6V-2Sn undergoes large dimensional changes during both initial aging between 673 and 973 0 K and subsequent exposure to low temperatures ( 0 K). These results indicate that if close dimensional tolerances must be maintained, duplex annealed Ti-6Al-6V-2Sn should be selected. Selection of treated and aged Ti-6Al-6V-2Sn should only be considered if accompanied by full scale environmental testing

  9. Alternating field losses in Nb3Sn multifilamentary superconductor

    International Nuclear Information System (INIS)

    Murphy, J.H.; Deis, D.W.; Shaw, B.J.; Walker, M.S.

    1975-01-01

    Transverse alternating field losses at 4.2K have been measured from 0.5 Hz to 10 kHz in a Nb 3 Sn multifilamentary superconductor in bias fields to 5 Tesla. The 0.020 inch diameter sample was prepared by heat treating a Cu, Nb-1 wt percent Zr, CuSn composite at 700 0 C for 20 hours to form Nb 3 Sn on the inside surface of the annular filaments. Metallurgical studies have been made to determine the Sn distribution and to estimate the thickness of the Nb 3 Sn layer. The I/sub c/-H curve and resistive and inductive transition curves are presented. The losses are analyzed with respect to the present loss theories using the conductor characteristics measured and excellent agreement between experiment and theory is achieved. 1 table, 6 figures

  10. Decay properties of nuclei in the neighbourhood of 100Sn

    International Nuclear Information System (INIS)

    Straub, Katrin

    2011-01-01

    This thesis concentrates on nuclear properties of very neutron deficient nuclei near the proton dripline in the neighbourhood of doubly-magic 100 Sn. In an experiment performed in March 2008 at the GSI in Darmstadt, the exotic nuclei were produced in a projectile fragmentation reaction using a 124 Xe primary beam with an energy of 100 AMeV impinging on a 4000 Beryllium target, separated and identified in the FRS and eventually stopped for decay spectroscopy in a complex implantation detector developed at the institute E12. The Germanium array RISING was employed for the measurement of prompt and delayed gamma radiation. Production cross sections and half lives were determined along the proton dripline. The isotopes 99 Sn, 97 In and 95 Cd were identified for the first time. additional nuclei studied in this thesis are 103 Sn, 96 Cd as well as the two tin isotopes 101 Sn and 102 Sn. (orig.)

  11. SiSn diodes: Theoretical analysis and experimental verification

    KAUST Repository

    Hussain, Aftab M.

    2015-08-24

    We report a theoretical analysis and experimental verification of change in band gap of silicon lattice due to the incorporation of tin (Sn). We formed SiSn ultra-thin film on the top surface of a 4 in. silicon wafer using thermal diffusion of Sn. We report a reduction of 0.1 V in the average built-in potential, and a reduction of 0.2 V in the average reverse bias breakdown voltage, as measured across the substrate. These reductions indicate that the band gap of the silicon lattice has been reduced due to the incorporation of Sn, as expected from the theoretical analysis. We report the experimentally calculated band gap of SiSn to be 1.11 ± 0.09 eV. This low-cost, CMOS compatible, and scalable process offers a unique opportunity to tune the band gap of silicon for specific applications.

  12. A Review of SnSe: Growth and Thermoelectric Properties

    Science.gov (United States)

    Nguyen, Van Quang; Kim, Jungdae; Cho, Sunglae

    2018-04-01

    SnSe is a 2D semiconductor with an indirect energy gap of 0.86 - 1 eV; it is widely used in solar cell, optoelectronics, and electronic device applications. Recently, SnSe has been considered as a robust candidate for energy conversion applications due to its high thermoelectric performance ( ZT = 2.6 in p-type and 2.2 in n-type), which is assigned mainly to its anhamornic bonding leading to an ultralow thermal conductivity. In this review, we first discuss the crystalline and electronic structures of SnSe and the source of its p-type characteristic. Then, some typical single crystal and polycrystal growth techniques, as well as an epitaxial thin film growth technique, are outlined. The reported thermoelectric properties of SnSe grown by using each technique are also reviewed. Finally, we will describe some remaining issues concerning the use of SnSe for thermoelectric applications.

  13. 99mTc bone scanning agents preparation and chemical analysis of Tc(Sn)pyrophosphate, Tc(Sn)MDP and Tc(Sn)HMDP

    International Nuclear Information System (INIS)

    Kroesbergen, J.

    1986-01-01

    This thesis describes a comparison of the preparation, composition and properties of three bone scanning agents: 99m Tc(Sn)pyrophosphate, 99m Tc(Sn)MDP and 99m Tc(Sn)HMDP. This study has been performed for two reasons: First to investigate the preparation and composition of the radiopharmaceuticals as a function of experimental conditions. Together with previously reported results for 99m Tc(Sn)EHDP, obtained in a similar way, this enables to use well-defined preparations of the bone scanning agents. Secondly to gain an insight in the mechanism in which the agents behave 'in vivo'. Because the 'in vivo' process is too complicated to study directly, it seemed more appropriate to perform 'in vitro' investigations as simplifications of the 'in vivo' situation. 304 refs.; 26 figs.; 31 tabs

  14. Gamma spectroscopy of multiple nucleon transfer reactions in Sn

    International Nuclear Information System (INIS)

    Grabowski, Z.W.; Mayer, R.H.; Fornal, B.; Nisius, D.T.; Bearden, I.G.; Daly, P.J.; Broda, R.; Carpenter, M.P.; Janssens, R.V.F.; Khoo, T.L.; Lauritsen, T.

    1992-01-01

    The decay of (πh 11/2 ) n yrast isomers was studied in a series of proton-rich N = 82 isotones culminating in determination of B(E2) values in 153 Lu and 154 Hf. In the N = 82 isotones however, it seems unlikely that the measurements could be extended beyond 154 Hf (n = 8). The opportunity to investigate the (h 11/2 ) n ) isomers across the whole h 11/2 subshell exists, at least in principle, in Sn isotopes where the counterpart νh 11/2 subshell is being filled with neutrons starting at 116 Sn. Before our measurements were initiated, the (νh 11/2 ) n 10 + isomers were known to exist in 116, 118, 120 Sn, where the νh 11/2 subshell begins to fill, and in 128,130 Sn at the other end. Important information, however, was missing about the 10 + isomers in 122,124,126 Sn where the long lifetimes are expected. The υ = 3 (h 11/2 ) isomers in odd tin isomers for A ≥ 119 were also not identified. A serious experimental difficulty in populating high spin states in heavier Sn isotopes is that they are not accessible by fusion-evaporation reactions. We decided to search for these missing tin isotopes among the products of heavy ion reactions on 122,124 Sn targets. Using this approach we were able to identify the isomeric decays and measure the lifetimes of the (νh 11/2 n ) υ = 2 isomeric states in 122,124 Sn. In odd tin isotopes we identified new I = 19/2 + yrast isomers in 119,121,123 Sn and measured their lifetimes. In addition (νh 11/2 ) n υ = 3, I = 27/2 - isomers in 119,121 Sn were observed for the first time

  15. Tracer diffusion studies of 26Mg, 30Si and 18O in single crystal forsterite (Mg2SiO4) and of 18O in single crystal SiO2

    International Nuclear Information System (INIS)

    Schachtner, R.

    1981-01-01

    Tracer diffusion coefficients of Mg, Si and O in monocrystalline forsterite were determined by Sims as a function of temperature and crystal orientation. Former results on oxygen diffusion in SiO 2 single crystals using nuclear activation methods were confirmed by Sims data. The influence of crystal defects and impurities is discussed. (TW)

  16. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    KAUST Repository

    Boualleg, Malika; Baudouin, David; Basset, Jean-Marie; Bayard, Franç ois; Candy, Jean Pierre; Jumas, Jean Claude; Veyre, Laurent; Thieuleux, Chloé

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained

  17. Carbon supported Pd-Sn and Pd-Ru-Sn nanocatalysts for ethanol electro-oxidation in alkaline medium

    CSIR Research Space (South Africa)

    Modibedi, RM

    2011-04-01

    Full Text Available Carbon supported Pd-Sn and Pd-Ru-Sn nanocatalysts were prepared by the chemical reduction method, using sodium borohydride and ethylene glycol mixture as the reducing agent. The catalytic activity towards ethanol electro-oxidation in alkaline medium...

  18. Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts

    DEFF Research Database (Denmark)

    Stevanović, S.; Tripković, D.; Tripkovic, Vladimir

    2014-01-01

    The role of Sn on the catalytic activity for CO and formic acid oxidation is studied by comparing the activities of differently treated PtSn/C and Pt/C catalysts. The catalysts are prepared by a microwave-assisted polyol synthesis method. As revealed by scanning tunneling and transmission electron...

  19. Crystal structure of R.E. NiSn and R.E. PdSn equiatomic compounds

    International Nuclear Information System (INIS)

    Dwight, A.E.

    1983-03-01

    Call constants and volume per formula weight are tabulated for RE NiSn (RE = La to Lu, Y) and RE PdSn (RE = Nd to Ho). The unit cell constants are also plotted versus ionic radius of the RE; trends are noted

  20. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    KAUST Repository

    Boualleg, Malika

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained spontaneously as the unique phase regardless of the number of tin equivalents introduced. © 2010 The Royal Society of Chemistry.

  1. First-principles study of ZnSnAs2-based dilute magnetic semiconductors

    Science.gov (United States)

    Kizaki, Hidetoshi; Morikawa, Yoshitada

    2018-02-01

    The electronic structure and magnetic properties of chalcopyrite Zn(Sn,TM)As2 and (Zn,TM)SnAs2 have been investigated by the Korringa-Kohn-Rostoker method combined with the coherent potential approximation within the local spin density approximation, where TM denotes a 3d transition metal element. We find that the half-metallic and high-spin ferromagnetic state can be obtained in Zn(Sn,V)As2, Zn(Sn,Cr)As2, Zn(Sn,Mn)As2, (Zn,V)SnAs2, and (Zn,Cr)SnAs2. The calculated result of Zn(Sn,Mn)As2 is in good agreement with the experimentally observed room-temperature ferromagnetism if we can control selective Mn doping at Sn sites. In addition, (Zn,V)SnAs2 and (Zn,Cr)SnAs2 are predicted to exhibit high-Curie-temperature ferromagnetism.

  2. Spliceosomal small nuclear RNAs of Tetrahymena thermophila and some possible snRNA-snRNA base-pairing interactions

    DEFF Research Database (Denmark)

    Orum, H; Nielsen, Henrik; Engberg, J

    1991-01-01

    We have identified and characterized the full set of spliceosomal small nuclear RNAs (snRNAs; U1, U2, U4, U5 and U6) from the ciliated protozoan Tetrahymena thermophila. With the exception of U4 snRNA, the sizes of the T. thermophila snRNAs are closely similar to their metazoan homologues. The T....... thermophila snRNAs all have unique 5' ends, which start with an adenine residue. In contrast, with the exception of U6, their 3' ends show some size heterogeneity. The primary sequences of the T. thermophila snRNAs contain the sequence motifs shown, or proposed, to be of functional importance in other...

  3. The interfacial free energy of solid Sn on the boundary interface with liquid Cd-Sn eutectic solution

    International Nuclear Information System (INIS)

    Saatci, B; Cimen, S; Pamuk, H; Guenduez, M

    2007-01-01

    Equilibrated grain boundary groove shapes for solid Sn in equilibrium with Cd-Sn liquid were directly observed after annealing a sample at the eutectic temperature for about 8 days. The thermal conductivities of the solid phase, K S , and the liquid phase, K L , for the groove shapes were measured. From the observed groove shapes, the Gibbs-Thomson coefficients were obtained with a numerical method, using the measured G, K S and K L values. The solid-liquid interfacial energy of solid Sn in equilibrium with Cd-Sn liquid was determined from the Gibbs-Thomson equation. The grain boundary energy for solid Sn was also calculated from the observed groove shapes

  4. DO22-(Cu,Ni)3Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

    International Nuclear Information System (INIS)

    Liu Lilin; Huang, Haiyou; Fu Ran; Liu Deming; Zhang Tongyi

    2009-01-01

    The present work conducts crystal characterization by High Resolution Transmission Electron Microscopy (HRTEM) on Cu/Sn-nanolayer/Ni sandwich structures associated with the use of Energy Dispersive X-ray (EDX) analysis. The results show that DO 22 -(Cu,Ni) 3 Sn intermetallic compound (IMC) ordered structure is formed in the sandwich structures at the as-electrodeposited state. The formed DO 22 -(Cu,Ni) 3 Sn IMC is a homogeneous layer with a thickness about 10 nm. The DO 22 -(Cu,Ni) 3 Sn IMC nanolayer is stable during annealing at 250 deg. C for 810 min. The formation and stabilization of the metastable DO 22 -(Cu,Ni) 3 Sn IMC nanolayer are attributed to the less strain energy induced by lattice mismatch between the DO 22 IMC and fcc Cu crystals in comparison with that between the equilibrium DO 3 IMC and fcc Cu crystals.

  5. Stable and metastable equilibria in PbSe + SnI2=SnSe + PbI2

    International Nuclear Information System (INIS)

    Odin, I.N.; Grin'ko, V.V.; Kozlovskij, V.F.; Demidova, E.D.

    2003-01-01

    T-x-y phase diagrams of the PbSe + SnI 2 =SnSe + PbI 2 mutual system (stable states) are plotted for the first time. It is shown that melt, solid solutions on the base of components of the mutual system and phase on the base of Sn 2 SeI 4 take part in phase equilibria. Transformations in the PbSe + SnI 2 =SnSe + PbI 2 mutual system leading to crystallization of metastable polytype modifications of lead iodides and metastable ternary compound forming in PbSe-PbI 2 system are investigated for the first time [ru

  6. Sn powder as reducing agents and SnO2 precursors for the synthesis of SnO2-reduced graphene oxide hybrid nanoparticles.

    Science.gov (United States)

    Chen, Mingxi; Zhang, Congcong; Li, Lingzhi; Liu, Yu; Li, Xichuan; Xu, Xiaoyang; Xia, Fengling; Wang, Wei; Gao, Jianping

    2013-12-26

    A facile approach to prepare SnO2/rGO (reduced graphene oxide) hybrid nanoparticles by a direct redox reaction between graphene oxide (GO) and tin powder was developed. Since no acid was used, it is an environmentally friendly green method. The SnO2/rGO hybrid nanoparticles were characterized by ultraviolet-visible spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The microstructure of the SnO2/rGO was observed with scanning electron microscopy and transmission electron microscopy. The tin powder efficiently reduced GO to rGO, and the Sn was transformed to SnO2 nanoparticles (∼45 nm) that were evenly distributed on the rGO sheets. The SnO2/rGO hybrid nanoparticles were then coated on an interdigital electrode to fabricate a humidity sensor, which have an especially good linear impedance response from 11% to 85% relative humidity.

  7. HPLC method for determination of SN-38 content and SN-38 entrapment efficiency in a novel liposome-based formulation, LE-SN38.

    Science.gov (United States)

    Xuan, Tong; Zhang, J Allen; Ahmad, Imran

    2006-05-03

    A simple HPLC method was developed for quantification of SN-38, 7-ethyl-10-hydroxycamptothecin, in a novel liposome-based formulation (LE-SN38). The chromatographic separation was achieved on an Agilent Zorbax SB-C18 (4.6 mmx250 mm, 5 microm) analytical column using a mobile phase consisting of a mixture of NaH2PO4 (pH 3.1, 25 mM) and acetonitrile (50:50, v/v). SN-38 was detected at UV wavelength of 265 nm and quantitatively determined using an external calibration method. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 0.05 and 0.25 microg/mL, respectively. The individual spike recovery of SN-38 ranged from 100 to 101%. The percent of relative standard deviation (%R.S.D.) of intra-day and inter-day analyses were less than 1.6%. The method validation results confirmed that the method is specific, linear, accurate, precise, robust and sensitive for its intended use. The current method was successfully applied to the determination of SN-38 content and drug entrapment efficiency in liposome-based formulation, LE-SN38 during early stage formulation development.

  8. Exploration work function and optical properties of monolayer SnSe allotropes

    Science.gov (United States)

    Cui, Zhen; Wang, Xia; Ding, Yingchun; Li, Meiqin

    2018-02-01

    The work function and optical properties are investigated with density functional theory for three monolayer SnSe allotropes. The calculated results indicate that the α-SnSe, δ-SnSe, ε-SnSe are semiconductor with the band gaps of 0.90, 1.25, and 1.50 eV, respectively. Meanwhile, the work function of δ-SnSe is lower than α-SnSe and ε-SnSe, which indicates that the δ-SnSe can be prepared of photoemission and field emission nanodevices. More importantly, the α-SnSe, δ-SnSe, ε-SnSe with the large static dielectric constants are 4.22, 5.48, and 3.61, which demonstrate that the three monolayer SnSe allotropes can be fabricated the capacitor. In addition, the static refractive index of δ-SnSe is larger than α-SnSe and ε-SnSe. The different optical properties with three monolayer SnSe allotropes reveal that the allotropes can regulate the properties of the materials. Moreover, our researched results show that the three monolayer SnSe allotropes are sufficient for fabrication of optoelectronic nanodevices.

  9. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo

    2014-12-01

    A new one pot, surfactant-free, synthetic route based on the surface organometallic chemistry (SOMC) concept has been developed for the synthesis of Sn surface-enriched Pt-Sn nanoparticles. Bu3SnH selectively reacts with [Pt]-H formed in situ at the surface of Pt nanoparticles, Pt NPs, obtained by reduction of K2PtCl4 by LiB(C2H5)3H. Chemical analysis, 1H MAS and 13C CP/MAS solid-state NMR as well as two-dimensional double-quantum (DQ) and triple-quantum (TQ) experiments show that organo-tin moieties Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as-synthesized Pt-Sn NPs, enabling the bimetallic NPs to be well dispersed in THF. Additionally, the Pt-Sn nanoparticles can be supported on MgAl2O4 during the synthesis of the nanoparticles. Some of the Pt-Sn/MgAl2O4 catalyst thus prepared exhibits high activity in PROX of CO and an extremely high selectivity and stability in propane dehydrogenation to propylene. The enhanced activity in propane dehydrogenation is associated with the high concentration of inactive Sn at the surface of Pt nanoparticles which ”isolates” the active Pt atoms. This conclusion is confirmed by XRD, NMR, TEM, and XPS analysis.

  10. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Hidayati

    2016-03-01

    Full Text Available Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC, choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220 crystalline face centred cubic (fcc Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 10-20. (doi:10.9767/bcrec.11.1.394.10-20 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-20

  11. Peculiarities of component interaction in {Gd, Er}-V-Sn Ternary systems at 870 K and crystal structure of RV6Sn6 stannides

    International Nuclear Information System (INIS)

    Romaka, L.; Stadnyk, Yu.; Romaka, V.V.; Demchenko, P.; Stadnyshyn, M.; Konyk, M.

    2011-01-01

    Highlights: → {Gd, Er}-V-Sn ternary systems at 870 K are characterized by formation of stannides with general compositions RV 6 Sn 6 . → Isostructural RV 6 Sn 6 compounds were also found with Y, Dy, Ho, Tm, and Lu. → The crystal structure of RV 6 Sn 6 compounds was determined by powder diffraction method. → Structural analysis showed that RV 6 Sn 6 compounds (R = Gd, Dy-Tm, Lu) are disordered; YV 6 Sn 6 is characterized by structure ordering. - Abstract: The phase equilibria in the Gd-V-Sn and Er-V-Sn ternary systems were studied at 870 K by means of X-ray and metallographic analyses in the whole concentration range. Both Gd-V-Sn and Er-V-Sn systems are characterized by formation of one ternary compound at investigated temperature, with stoichiometry RV 6 Sn 6 (SmMn 6 Sn 6 -type, space group P6/mmm, a = 0.55322(3) nm, c = 0.91949(7) nm for Gd, a = 0.55191(2) nm, c = 0.91869(8) nm for Er). Solubility of the third component in the binary compounds was not observed. Compounds with the SmMn 6 Sn 6 -type were also found with Dy, Ho, Tm, and Lu, while YV 6 Sn 6 compound crystallizes in HfFe 6 Ge 6 structure type. All investigated compounds are the first ternary stannides with rare earth elements and vanadium.

  12. Host Galaxy Spectra and Consequences for SN Typing from the SDSS SN Survey

    Energy Technology Data Exchange (ETDEWEB)

    Olmstead, Matthew D.; Brown, Peter J.; Sako, Masao; Bassett, Bruce; Bizyaev, Dmitry; Brinkmann, J.; Brownstein, Joel R.; Brewington, Howard; Campbell, Heather; D’Andrea, Chris B.; Dawson, Kyle S.; Ebelke, Garrett L.; Frieman, Joshua A.; Galbany, Lluís; Garnavich, Peter; Gupta, Ravi R.; Hlozek, Renee; Jha, Saurabh W.; Kunz, Martin; Lampeitl, Hubert; Malanushenko, Elena; Malanushenko, Viktor; Marriner, John; Miquel, Ramon; Montero-Dorta, Antonio D.; Nichol, Robert C.; Oravetz, Daniel J.; Pan, Kaike; Schneider, Donald P.; Simmons, Audrey E.; Smith, Mathew; Snedden, Stephanie A.

    2014-03-06

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey (BOSS), this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of supernova (SN) host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future nalysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. When using the SALT2 light curve fitter, we find a 21% increase in the number of fits that converge when using the spectroscopic redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased towards lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  13. SnSAG5 is an alternative surface antigen of Sarcocystis neurona strains that is mutually exclusive to SnSAG1.

    Science.gov (United States)

    Crowdus, Carolyn A; Marsh, Antoinette E; Saville, Willliam J; Lindsay, David S; Dubey, J P; Granstrom, David E; Howe, Daniel K

    2008-11-25

    Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). Previous work has identified a gene family of paralogous surface antigens in S. neurona called SnSAGs. These surface proteins are immunogenic in their host animals, and are therefore candidate molecules for development of diagnostics and vaccines. However, SnSAG diversity exists in strains of S. neurona, including the absence of the major surface antigen gene SnSAG1. Instead, sequence for an alternative SnSAG has been revealed in two of the SnSAG1-deficient strains. Herein, we present data characterizing this new surface protein, which we have designated SnSAG5. The results indicated that the protein encoded by the SnSAG5 sequence is indeed a surface-associated molecule that has characteristics consistent with the other SAGs identified in S. neurona and related parasites. Importantly, Western blot analyses of a collection of S. neurona strains demonstrated that 6 of 13 parasite isolates express SnSAG5 as a dominant surface protein instead of SnSAG1. Conversely, SnSAG5 was not detected in SnSAG1-positive strains. One strain, which was isolated from the brain of a sea otter, did not express either SnSAG1 or SnSAG5. Genetic analysis with SnSAG5-specific primers confirmed the presence of the SnSAG5 gene in Western blot-positive strains, while also suggesting the presence of a novel SnSAG sequence in the SnSAG1-deficient, SnSAG5-deficient otter isolate. The findings provide further indication of S. neurona strain diversity, which has implications for diagnostic testing and development of vaccines against EPM as well as the population biology of Sarcocystis cycling in the opossum definitive host.

  14. GeSn growth kinetics in reduced pressure chemical vapor deposition from Ge2H6 and SnCl4

    Science.gov (United States)

    Aubin, J.; Hartmann, J. M.

    2018-01-01

    We have investigated the low temperature epitaxy of high Sn content GeSn alloys in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition tool from Applied Materials. Gaseous digermane (Ge2H6) and liquid tin tetrachloride (SnCl4) were used as the Ge and Sn precursors, respectively. The impact of temperature (in the 300-350 °C range), Ge2H6 and SnCl4 mass-flows on the GeSn growth kinetics at 100 Torr has been thoroughly explored. Be it at 300 °C or 325 °C, a linear GeSn growth rate increase together with a sub-linear Sn concentration increase occurred as the SnCl4 mass-flow increased, irrespective of the Ge2H6 mass flow (fixed or varying). The Sn atoms seemed to catalyze H desorption from the surface, resulting in higher GeSn growth rates for high SnCl4 mass-flows (in the 4-21 nm min-1 range). The evolution of the Sn content x with the F (SnCl4) 2 ·/F (Ge2H6) mass-flow ratio was fitted by x2/(1 - x) = n ·F (SnCl4) 2 ·/F (Ge2H6), with n = 0.25 (325 °C) and 0.60 (300 °C). We have otherwise studied the impact of temperature, in the 300-350 °C range, on the GeSn growth kinetics. The GeSn growth rate exponentially increased with the temperature, from 15 up to 32 nm min-1. The associated activation energy was low, i.e. Ea = 10 kcal mol-1. Meanwhile, the Sn content decreased linearly as the growth temperature increased, from 15% at 300 °C down to 6% at 350 °C.

  15. $Nb_{3}Sn macrostructure, microstructure, and property comparisons for bronze and internal Sn process strands

    CERN Document Server

    Lee, P J; Larbalestier, D C

    2000-01-01

    The variation in irreversibility field, B*(T), with temperature has been measured for Nb/sub 3/Sn superconducting strands manufactured for ITER using vibrating sample and SQUID magnetometers. The high performance strands were developed for both high transport critical current density, J/sub c/, and low hysteresis loss. Despite a wide variety of designs and components, the strands could be split into two distinctive groups, based on the extrapolated irreversibility fields, which lie about 10% lower than the upper critical field. "Bronze-process" strands exhibited consistently higher B*(T) (28 T to 31 T) compared with "internal Sn" process (24 T to 26 T) conductors. The intrinsic critical current density of the superconductor, J/sub c (sc)/, and the specific pinning force of the grain boundaries, Q/sub gb/, were evaluated using the measured J/sub c/, and image analysis of the macro- and micro-structures. A bronze-processed Nb(-Ta)/sub 3 /Sn was found to have a higher J/sub c(sc)/ but lower Q/sub gb/ than Nb/sub...

  16. Convective instabilities in SN 1987A

    Science.gov (United States)

    Benz, Willy; Thielemann, Friedrich-Karl

    1990-01-01

    Following Bandiera (1984), it is shown that the relevant criterion to determine the stability of a blast wave, propagating through the layers of a massive star in a supernova explosion, is the Schwarzschild (or Ledoux) criterion rather than the Rayleigh-Taylor criterion. Both criteria coincide only in the incompressible limit. Results of a linear stability analysis are presented for a one-dimensional (spherical) explosion in a realistic model for the progenitor of SN 1987A. When applying the Schwarzschild criterion, unstable regions get extended considerably. Convection is found to develop behind the shock, with a characteristic growth rate corresponding to a time scale much smaller than the shock traversal time. This ensures that efficient mixing will take place. Since the entire ejected mass is found to be convectively unstable, Ni can be transported outward, even into the hydrogen envelope, while hydrogen can be mixed deep into the helium core.

  17. Origin of low thermal conductivity in SnSe

    Science.gov (United States)

    Xiao, Yu; Chang, Cheng; Pei, Yanling; Wu, Di; Peng, Kunling; Zhou, Xiaoyuan; Gong, Shengkai; He, Jiaqing; Zhang, Yongsheng; Zeng, Zhi; Zhao, Li-Dong

    2016-09-01

    We provide direct evidence to understand the origin of low thermal conductivity of SnSe using elastic measurements. Compared to state-of-the-art lead chalcogenides Pb Q (Q =Te , Se, S), SnSe exhibits low values of sound velocity (˜1420 m /s ) , Young's modulus (E ˜27.7 GPa ) , and shear modulus (G ˜9.6 GPa ) , which are ascribed to the extremely weak Sn-Se atomic interactions (or bonds between layers); meanwhile, the deduced average Grüneisen parameter γ of SnSe is as large as ˜3.13, originating from the strong anharmonicity of the bonding arrangement. The calculated phonon mean free path (l ˜ 0.84 nm) at 300 K is comparable to the lattice parameters of SnSe, indicating little room is left for further reduction of the thermal conductivity through introducing nanoscale microstructures and microscale grain boundaries. The low elastic properties indicate that the weak chemical bonding stiffness of SnSe generally causes phonon modes softening which eventually slows down phonon propagation. This work provides insightful data to understand the low lattice thermal conductivity of SnSe.

  18. Fluxless Sn-Ag bonding in vacuum using electroplated layers

    International Nuclear Information System (INIS)

    Kim, Jongsung; Lee, Chin C.

    2007-01-01

    A fluxless bonding process in vacuum environment using newly developed electroplated Sn-Ag multilayer structure at eutectic composition is presented. The new bonding process is entirely fluxless, or flux-free. It is performed in vacuum (100 mTorr), in which the oxygen content is reduced by a factor of 7600 comparing to air, to inhibit solder oxidation. In the design, Cr/Au dual layer is employed as the UBM as well as the plating seed layer. This UBM design, seldom used in the electronic industry, is explained in some details. To realize the fluxless possibility, a proper layer design of the solder structure is needed. In this connection, we wish to point out that it is hard to achieve fluxless bonding using Sn-rich alloys because these alloys have numerous Sn atoms on the surface that are easily oxidized. To prevent Sn oxidation, a thin Ag layer is plated immediately over Sn layer. XRD results confirm that this thin Ag layer does act as a barrier to prevent oxidation of the inner Sn layer. The resulting solder joints are void free as examined by a scanning acoustic microscope (SAM). SEM and EDX studies on the cross section of the joint indicate a homogeneous Sn-rich phase. The melting temperature is measured to be between 219 and 226 deg. C. This new fluxless bonding process is valuable in many applications where the use of flux is prohibited

  19. Synthesis and characterization of different morphological SnS nanomaterials

    International Nuclear Information System (INIS)

    Chaki, Sunil H; Chaudhary, Mahesh D; Deshpande, M P

    2014-01-01

    SnS in three nano forms possessing different morphologies such as particles, whiskers and ribbons were synthesised by chemical route. The morphology variation was brought about in the chemical route synthesis by varying a synthesis parameter such as temperature and influencing the synthesis by use of surfactant. The elemental composition determination by energy dispersive analysis of x-rays (EDAX) showed that all three synthesized SnS nanomaterials were tin deficient. The x-ray diffraction (XRD) study of the three SnS nanomaterials showed that all of them possess orthorhombic structure. The Raman spectra of the three SnS nanomaterials showed that all three samples possess three common distinguishable peaks. In them two peaks lying at 98 ± 1 cm −1 and 224 ± 4 cm −1 are the characteristic A g mode of SnS. The third peak lying at 302 ± 1 cm −1 is associated with secondary Sn 2 S 3 phase. The transmission electron microscopy (TEM) confirmed the respective morphologies. The optical analysis showed that they possess direct as well as indirect optical bandgap. The electrical transport properties study on the pellets prepared from the different nanomaterials of SnS showed them to be semiconducting and p-type in nature. The current–voltage (I–V) plots of the silver (Ag)/SnS nanomaterials pellets for dark and incandescent illumination showed that all configurations showed good ohmic behaviour except Ag/SnS nanoribbons pellet configuration under illumination. All the obtained results are discussed in detail. (paper)

  20. Characteristics and heat treatment of cold-sprayed Al-Sn binary alloy coatings

    International Nuclear Information System (INIS)

    Ning, Xian-Jin; Kim, Jin-Hong; Kim, Hyung-Jun; Lee, Changhee

    2009-01-01

    In this study, Al-Sn binary alloy coatings were prepared with Al-5 wt.% Sn (Al-5Sn) and Al-10 wt.% Sn (Al-10Sn) gas atomized powders by low pressure and high pressure cold spray process. The microstructure and microhardness of the coatings were characterized. To understand the coarsening of tin in the coating, the as-sprayed coatings were annealed at 150, 200, 250 and 300 o C for 1 h, respectively. The effect of annealing on microstructure and the bond strength of the coatings were investigated. The results show that Al-5Sn coating can be deposited by high pressure cold spray with nitrogen while Al-10Sn can only be deposited by low pressure cold spray with helium gas. Both Al-5Sn and Al-10Sn coatings present dense structures. The fraction of Sn in as-sprayed coatings is consistent with that in feed stock powders. The coarsening and/or migration of Sn phase in the coatings were observed when the annealing temperature exceeds 200 deg. C. Furthermore, the microhardness of the coatings decreased significantly at the annealing temperature of 250 deg. C. EDXA analysis shows that the heat treatment has no significant effect on fraction of Sn phase in Al-5Sn coatings. Bonding strength of as-sprayed Al-10Sn coating is slightly higher than that of Al-5Sn coating. Annealing at 200 o C can increase the bonding strength of Al-5Sn coatings.

  1. Spark plasma-sintered Sn-based intermetallic alloys and their Li-storage studies

    CSIR Research Space (South Africa)

    Nithyadharseni, P

    2016-06-01

    Full Text Available In the present study, SnSb, SnSb/Fe, SnSb/Co, and SnSb/Ni alloy powders processed by co-precipitation were subjected to spark plasma-sintering (SPS) at 400 °C for 5 min. The compacts were structurally and morphologically characterized by X...

  2. Directional Solidification and Liquidus Projection of the Sn-Co-Cu System

    Science.gov (United States)

    Chen, Sinn-Wen; Chang, Jui-Shen; Pan, Kevin; Hsu, Chia-Ming; Hsu, Che-Wei

    2013-04-01

    This study investigates the Sn-Co-Cu ternary system, which is of interest to the electronics industry. Ternary Sn-Co-Cu alloys were prepared, their as-solidified microstructures were examined, and their primary solidification phases were determined. The primary solidification phases observed were Cu, Co, Co3Sn2, CoSn, CoSn2, Cu6Sn5, Co3Sn2, γ, and β phases. Although there are ternary compounds reported in this ternary system, no ternary compound was found as the primary solidification phase. The directional solidification technique was applied when difficulties were encountered using the conventional quenching method to distinguish the primary solidification phases, such as Cu6Sn5, Cu3Sn, and γ phases. Of all the primary solidification phases, the Co3Sn2 and Co phases have the largest compositional regimes in which alloys display them as the primary solidification phases. There are four class II reactions and four class III reactions. The reactions with the highest and lowest reaction temperatures are both class III reactions, and are L + CoSn2 + Cu6Sn5 = CoSn3 at 621.5 K (348.3 °C) and L + Co3Sn2 + CoSn = Cu6Sn5 at 1157.8 K (884.6 °C), respectively.

  3. Highly Active, Carbon-supported, PdSn Nano-core, Partially ...

    African Journals Online (AJOL)

    Carbon-supported, Pt partially covered, PdSn alloy nanoparticles (Pt-PdSn/C) were synthesized via a metathetical reaction of PdSn alloy nanoparticles, and a platinum precursor. The electrochemical activity was evaluated by methanol oxidation. The Pt-PdSn/C catalysts were characterized by transmission electron ...

  4. Amorphous magnetism in Mnx Sn1-x alloys

    International Nuclear Information System (INIS)

    Drago, V.; Saitovitch, E.M.B.; Abd-Elmeguid, M.M.

    1988-01-01

    Systematic low temperature in situ 119 Sn Moessbauer effect (ME) studies in vapor quenched amorphous Mn x Sn 1-x (0.09≤ x ≤0,95) alloys between 150 and 4.2 K, are presented. Its is shown that the magnetic behavior of the system is correctly displayed by the transferred magnetic hyperfine (hf) interactions, at the 119 Sn site. A complete magnetic phase diagram is proposed, and the effect of an external magnetic field (up to about 3T) on the spin correlations in the spin-glass state is also discussed. (author) [pt

  5. Matter suppression of collective SN neutrino oscillations and stability analysis

    International Nuclear Information System (INIS)

    Saviano, N.; Chakraborty, S.; Mirizzi, A.

    2014-01-01

    We perform a detailed analysis of the supernova (SN) neutrino flavor evolution during the early time accretion phase (post-bounce time t pb ≤ 500 ms), characterizing the ν signal by recent SN hydrodynamics simulations. We find that collective oscillations induced the ν-ν interactions in the deepest SN regions are suppressed by trajectory-dependent 'multi-angle' effects associated with the dense ordinary matter. We confirm this result with a linearized stability analysis of the neutrino equations of motion in presence of realistic neutrino energy with angle distributions. (authors)

  6. Surface tension modelling of liquid Cd-Sn-Zn alloys

    Science.gov (United States)

    Fima, Przemyslaw; Novakovic, Rada

    2018-06-01

    The thermodynamic model in conjunction with Butler equation and the geometric models were used for the surface tension calculation of Cd-Sn-Zn liquid alloys. Good agreement was found between the experimental data for limiting binaries and model calculations performed with Butler model. In the case of ternary alloys, the surface tension variation with Cd content is better reproduced in the case of alloys lying on vertical sections defined by high Sn to Zn molar fraction ratio. The calculated surface tension is in relatively good agreement with the available experimental data. In addition, the surface segregation of liquid ternary Cd-Sn-Zn and constituent binaries has also been calculated.

  7. Synthesis of [119mSn]-mesoporphyrin IX dichloride

    International Nuclear Information System (INIS)

    Denissen, J.F.

    1990-01-01

    Tin mesoporphyrin IX dichloride (Sn-MPCl 2 ) is a heme oxygenase inhibitor of current clinical interest for the treatment of neonatal hyperbilirubinemia. The synthesis of [ 119m Sn]-MPCl 2 for drug metabolism and disposition studies is reported. [ 119m Sn]-MPCl 2 was prepared in 60% radiochemical yield by metalation of the porphyrin nucleus of mesoporphyrin IX dihydrochloride with tin(II)-119m acetate. The product had a specific activity of 43.4 mCi/mmol and a radiochemical purity of 99%, as determined by radio-HPLC analysis. (author)

  8. Decays of 116Sb isomers to levels in 116Sn

    International Nuclear Information System (INIS)

    Gacsi, Z.; Raman, S.

    1994-01-01

    The excited states of 116 Sn were studied by means of the decays of the 15.8-min, 3 + 116 Sb ground state, and the 60.3-min, 8 - 116 Sb isomer. Over 50 γ rays were observed; these were incorporated into a level scheme consisting of 32 excited states. Except for one new level proposed at 3.986 MeV, the current study fully supports an exhaustive study of levels in 116 Sn reported earlier. The previous study was an attempt to develop a nearly ''complete'' level scheme of 116 Sn up to an excitation energy of 4.3 MeV

  9. GaInSn usage in the research laboratory

    International Nuclear Information System (INIS)

    Morley, N. B.; Burris, J.; Cadwallader, L. C.; Nornberg, M. D.

    2008-01-01

    GaInSn, a eutectic alloy, has been successfully used in the Magneto-Thermofluid Research Laboratory at the University of California-Los Angeles and at the Princeton Plasma Physics Laboratory for the past six years. This paper describes the handling and safety of GaInSn based on the experience gained in these institutions, augmented by observations from other researchers in the liquid metal experimental community. GaInSn is an alloy with benign properties and shows considerable potential in liquid metal experimental research and cooling applications

  10. Effect of Nb on the Growth Behavior of Co3Sn2 Phase in Undercooled Co-Sn Melts

    Science.gov (United States)

    Kang, Jilong; Xu, Wanqiang; Wei, Xiuxun; Ferry, Michael; Li, Jinfu

    2016-12-01

    The growth behavior of the primary β-Co3Sn2 phase in (Co67Sn33)100- x Nb x ( x = 0, 0.5, 0.8, 1.0) hypereutectic alloys at different melt undercoolings was investigated systematically. The growth pattern of the β-Co3Sn2 phase at low undercooling changes with the Nb content from fractal seaweed ( x = 0, 0.5) into dendrite ( x = 0.8) and then returns to fractal seaweed ( x = 1.0) as a response to the changes in interface energy anisotropy and interface kinetic anisotropy. As undercooling increases, the dendritic growth of the β-Co3Sn2 phase in (Co67Sn33)99.2Nb0.8 alloy gives way to fractal seaweed growth at an undercooling of 32 K (-241 °C). At larger undercooling, the fractal seaweed growth is further replaced by compact seaweed growth, which occurred in the other three alloys investigated. The growth velocity of the β-Co3Sn2 phase slightly increases at low and intermediate undercooling but clearly decreases at larger undercooling due to the Nb addition. The growth velocity sharply increases as the growth pattern of the Co3Sn2 phase transits from fractal seaweed into compact seaweed.

  11. Improvements in the critical current densities of Nb3Sn by solid solution additions of Sn in Nb

    International Nuclear Information System (INIS)

    Luhman, T.; Suenaga, M.

    1975-01-01

    The effectiveness of solid solution additions of Sn to Nb in improving the superconducting properties of diffusion processed Nb 3 Sn conductors was examined. It was found that an increase in the superconducting critical current density, Jc, as function of layer thickness (d) may be obtained for thick Nb 3 Sn layers by solid solution additions of Sn in Nb. A large increase in J/sub c/ (d) is also achieved by increasing the Sn content in the bronze matrix material. In addition to uses of this material in magnet fabrications a potential application of these improved J/sub c/(d) values may lie in the use of Nb 3 Sn in power transmission lines. Here, a high superconducting critical current density is necessary throughout the material to carry the increased current during fault conditions. The magnetic field dependence of J/sub c/ is a function of alloy content but the alloying changes studied here do not increase the high field critical current capability of Nb 3 Sn. (auth)

  12. SN 2008iy: An Unusual Type IIn Supernova with an Enduring 400 Day Rise Time

    OpenAIRE

    Miller, A. A.; Silverman, J. M.; Butler, N. R.; Bloom, J. S.; Chornock, R.; Filippenko, A. V.; Ganeshalingam, M.; Klein, C. R.; Li, W.; Nugent, P. E.; Smith, N.; Steele, T. N.

    2009-01-01

    We present spectroscopic and photometric observations of the Type IIn supernova (SN) 2008iy. SN 2008iy showed an unprecedentedly long rise time of ~400 days, making it the first SN to take significantly longer than 100 days to reach peak optical luminosity. The peak absolute magnitude of SN 2008iy was M_r ~ -19.1 mag, and the total radiated energy over the first ~700 days was ~2 x 10^50 erg. Spectroscopically, SN 2008iy is very similar to the Type IIn SN 1988Z at late times, and, like SN 1988...

  13. Temperature varying photoconductivity of GeSn alloys grown by chemical vapor deposition with Sn concentrations from 4% to 11%

    Energy Technology Data Exchange (ETDEWEB)

    Hart, John; Hazbun, Ramsey; Gupta, Jay; Kolodzey, James [Department of Electrical Engineering, University of Delaware, 140 Evans Hall, Newark, Delaware 19716 (United States); Adam, Thomas [College of Nanoscale Science and Engineering, SUNY, Albany, New York 12203 (United States); Kim, Yihwan; Huang, Yi-Chiau [Applied Materials, Sunnyvale, California 94085 (United States); Reznicek, Alexander [IBM Research at Albany Nanotech, Albany, New York 12203 (United States)

    2016-03-07

    Pseudomorphic GeSn layers with Sn atomic percentages between 4.5% and 11.3% were grown by chemical vapor deposition using digermane and SnCl{sub 4} precursors on Ge virtual substrates grown on Si. The layers were characterized by x-ray diffraction rocking curves and reciprocal space maps. Photoconductive devices were fabricated, and the dark current was found to increase with Sn concentration. The responsivity of the photoconductors was measured at a wavelength of 1.55 μm using calibrated laser illumination at room temperature and a maximum value of 2.7 mA/W was measured for a 4.5% Sn device. Moreover, the responsivity for higher Sn concentration was found to increase with decreasing temperature. Spectral photoconductivity was measured using Fourier transform infrared spectroscopy. The photoconductive absorption edge continually increased in wavelength with increasing tin percentage, out to approximately 2.4 μm for an 11.3% Sn device. The direct band gap was extracted using Tauc plots and was fit to a bandgap model accounting for layer strain and Sn concentration. This direct bandgap was attributed to absorption from the heavy-hole band to the conduction band. Higher energy absorption was also observed, which was thought to be likely from absorption in the light-hole band. The band gaps for these alloys were plotted as a function of temperature. These experiments show the promise of GeSn alloys for CMOS compatible short wave infrared detectors.

  14. Temperature varying photoconductivity of GeSn alloys grown by chemical vapor deposition with Sn concentrations from 4% to 11%

    International Nuclear Information System (INIS)

    Hart, John; Hazbun, Ramsey; Gupta, Jay; Kolodzey, James; Adam, Thomas; Kim, Yihwan; Huang, Yi-Chiau; Reznicek, Alexander

    2016-01-01

    Pseudomorphic GeSn layers with Sn atomic percentages between 4.5% and 11.3% were grown by chemical vapor deposition using digermane and SnCl 4 precursors on Ge virtual substrates grown on Si. The layers were characterized by x-ray diffraction rocking curves and reciprocal space maps. Photoconductive devices were fabricated, and the dark current was found to increase with Sn concentration. The responsivity of the photoconductors was measured at a wavelength of 1.55 μm using calibrated laser illumination at room temperature and a maximum value of 2.7 mA/W was measured for a 4.5% Sn device. Moreover, the responsivity for higher Sn concentration was found to increase with decreasing temperature. Spectral photoconductivity was measured using Fourier transform infrared spectroscopy. The photoconductive absorption edge continually increased in wavelength with increasing tin percentage, out to approximately 2.4 μm for an 11.3% Sn device. The direct band gap was extracted using Tauc plots and was fit to a bandgap model accounting for layer strain and Sn concentration. This direct bandgap was attributed to absorption from the heavy-hole band to the conduction band. Higher energy absorption was also observed, which was thought to be likely from absorption in the light-hole band. The band gaps for these alloys were plotted as a function of temperature. These experiments show the promise of GeSn alloys for CMOS compatible short wave infrared detectors.

  15. Behavior of Sn atoms in GeSn thin films during thermal annealing: Ex-situ and in-situ observations

    Science.gov (United States)

    Takase, Ryohei; Ishimaru, Manabu; Uchida, Noriyuki; Maeda, Tatsuro; Sato, Kazuhisa; Lieten, Ruben R.; Locquet, Jean-Pierre

    2016-12-01

    Thermally induced crystallization processes for amorphous GeSn thin films with Sn concentrations beyond the solubility limit of the bulk crystal Ge-Sn binary system have been examined by X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, and (scanning) transmission electron microscopy. We paid special attention to the behavior of Sn before and after recrystallization. In the as-deposited specimens, Sn atoms were homogeneously distributed in an amorphous matrix. Prior to crystallization, an amorphous-to-amorphous phase transformation associated with the rearrangement of Sn atoms was observed during heat treatment; this transformation is reversible with respect to temperature. Remarkable recrystallization occurred at temperatures above 400 °C, and Sn atoms were ejected from the crystallized GeSn matrix. The segregation of Sn became more pronounced with increasing annealing temperature, and the ejected Sn existed as a liquid phase. It was found that the molten Sn remains as a supercooled liquid below the eutectic temperature of the Ge-Sn binary system during the cooling process, and finally, β-Sn precipitates were formed at ambient temperature.

  16. A highly stable (SnOx-Sn)@few layered graphene composite anode of sodium-ion batteries synthesized by oxygen plasma assisted milling

    Science.gov (United States)

    Cheng, Deliang; Liu, Jiangwen; Li, Xiang; Hu, Renzong; Zeng, Meiqing; Yang, Lichun; Zhu, Min

    2017-05-01

    The (SnOx-Sn)@few layered graphene ((SnOx-Sn)@FLG) composite has been synthesized by oxygen plasma-assisted milling. Owing to the synergistic effect of rapid plasma heating and ball mill grinding, SnOx (1 ≤ x ≤ 2) nanoparticles generated from the reaction of Sn with oxygen are tightly wrapped by FLG nanosheets which are simultaneously exfoliated from expanded graphite, forming secondary micro granules. Inside the granules, the small size of the SnOx nanoparticles enables the fast kinetics for Na+ transfer. The in-situ formed FLG and residual Sn nanoparticles improve the electrical conductivity of the composite, meanwhile alleviate the aggregation of SnOx nanoparticles and relieve the volume change during the cycling, which is beneficial for the cyclic stability for the Na+ storage. As an anode material for sodium-ion batteries, the (SnOx-Sn)@FLG composite exhibits a high reversible capacity of 448 mAh g-1 at a current density of 100 mA g-1 in the first cycle, with 82.6% capacity retention after 250 cycles. Even when the current density increases to 1000 mA g-1, this composite retains 316.5 mAh g-1 after 250 cycles. With superior Na+ storage stability, the (SnOx-Sn)@FLG composite can be a promising anode material for high performance sodium-ion batteries.

  17. Comparative study of SnS recrystallization in molten CdI{sub 2}, SnCl{sub 2}and KI

    Energy Technology Data Exchange (ETDEWEB)

    Timmo, Kristi; Kauk-Kuusik, Marit; Pilvet, Maris; Mikli, Valdek; Kaerber, Erki; Raadik, Taavi; Leinemann, Inga; Altosaar, Mare; Raudoja, Jaan [Department of Materials Science, Tallinn University of Technology, Tallinn (Estonia)

    2016-01-15

    In the present study, the recrystallization of polycrystalline SnS in different molten salts CdI{sub 2}, SnCl{sub 2} and KI as flux materials are presented. The recrystallization and growth of polycrystalline material in molten salts produces unique SnS monograin powders usable in monograin layer solar cells. XRD and Raman analysis revealed that single phase SnS powder can be obtained in KI at 740 C and in SnCl{sub 2} at 500 C. Long time heating of SnS in molten CdI{sub 2} was accompanied by chemical interaction between SnS and CdI{sub 2} that resulted in a mixture of CdS and Sn{sub 2}S{sub 3} crystals. SEM images showed that morphology of crystals can be controlled by the nature of the flux materials: needle-like Sn{sub 2}S{sub 3} together with round edged crystals of CdS in CdI{sub 2}, flat crystals of SnS with smooth surfaces in SnCl{sub 2} and well-formed SnS crystals with rounded edges in KI had been formed. The temperatures of phase transitions and/or the interactions of SnS and flux materials were determined by differential thermal analysis. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Pulsed laser deposition of Cu-Sn-S for thin film solar cells

    DEFF Research Database (Denmark)

    Ettlinger, Rebecca Bolt; Crovetto, Andrea; Bosco, Edoardo

    Thin films of copper tin sulfide were deposited from a target of the stoichiometry Cu:Sn:S ~1:2:3 using pulsed laser deposition (PLD). Annealing with S powder resulted in films close to the desired Cu2SnS3 stoichiometry although the films remained Sn rich. Xray diffraction showed that the final...... films contained both cubic-phase Cu2SnS3 and orthorhombic-phase SnS...

  19. Stabilization of a Nb3Sn persistent current switch

    International Nuclear Information System (INIS)

    Urata, M.; Maeda, H.; Nakayama, S.; Yoneda, E.; Oda, Y.; Kumano, T.; Aoki, N.; Tomisaki, T.; Kabashima, S.

    1993-01-01

    A 2000 A class Nb 3 Sn persistent current switch has been successfully fabricated in the Toshiba R and D Center. The Nb tube processed conductor with Cu-10 wt.% Ni matrix has been developed for the switch in the Showa Electric Wire and Cable Co. Ltd. The magnetic instability which was observed in the previous 35 Ω Nb 3 Sn persistent current switch was improved in the present switch. The problem of quench current degradation and flux jump on magnetization, emerged in the previous switch, were confirmed to be solved. In the fast ramp, however, the switch degrades from the calculated results assuming the self field ac loss. In the Nb 3 Sn reaction process, Sn in the bronze diffuses into the Nb tube, which decreases the switch resistance. It was observed by a computer aided micro analysis (CMA) that Ni in the CuNi matrix precipitated on the Nb tube, which slightly reduced the switch resistance. (orig.)

  20. Electronic structure of shandite Co3Sn2S2

    Science.gov (United States)

    Dedkov, Y. S.; Holder, M.; Molodtsov, S. L.; Rosner, H.

    2008-03-01

    The electronic structure of shandite Co3Sn2S2 was determined by photoelectron spectroscopy and compared with ab initio band structure calculations. Presented results give evidence that this compound has half-metallic ferromagnetic properties.

  1. TDPAC study of Cd-doped SnO

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, E. L., E-mail: munoz@fisica.unlp.edu.ar [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina); Carbonari, A. W. [Instituto de Pesquisas Energeticas y Nucleares-IPEN-CNEN/SP (Brazil); Errico, L. A. [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina); Bibiloni, A. G. [Universidad Nacional de La Plata, Departamento de Fisica, Facultad de Ciencias Exactas (Argentina); Petrilli, H. M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil); Renteria, M. [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina)

    2007-07-15

    The combination of hyperfine techniques and ab initio calculations has been shown to be a powerful tool to unravel structural and electronic characterizations of impurities in solids. A recent example has been the study of Cd-doped SnO, where ab initio calculations questioned previous TDPAC assignments of the electric-field gradient (EFG) in {sup 111}In-implanted Sn-O thin films. Here we present new TDPAC experiments at {sup 111}In-diffused polycrystalline SnO. A reversible temperature dependence of the EFG was observed in the range 295-900 K. The TDPAC results were compared with theoretical calculations performed with the full-potential linearized augmented plane wave (FP-LAPW) method, in the framework of the density functional theory. Through the comparison with the theoretical results, we infer that different electronic surroundings around Cd impurities can coexist in the SnO sample.

  2. TDPAC study of Cd-doped SnO

    International Nuclear Information System (INIS)

    Munoz, E. L.; Carbonari, A. W.; Errico, L. A.; Bibiloni, A. G.; Petrilli, H. M.; Renteria, M.

    2007-01-01

    The combination of hyperfine techniques and ab initio calculations has been shown to be a powerful tool to unravel structural and electronic characterizations of impurities in solids. A recent example has been the study of Cd-doped SnO, where ab initio calculations questioned previous TDPAC assignments of the electric-field gradient (EFG) in 111 In-implanted Sn-O thin films. Here we present new TDPAC experiments at 111 In-diffused polycrystalline SnO. A reversible temperature dependence of the EFG was observed in the range 295-900 K. The TDPAC results were compared with theoretical calculations performed with the full-potential linearized augmented plane wave (FP-LAPW) method, in the framework of the density functional theory. Through the comparison with the theoretical results, we infer that different electronic surroundings around Cd impurities can coexist in the SnO sample.

  3. Crystallographic disorder and magnetism in UPd2-xSn

    International Nuclear Information System (INIS)

    Suellow, S.; Mattheus, C.C.; Becker, B.; Snel, C.E.; Nieuwenhuys, G.J.; Mydosh, J.A.; Schenck, A.

    1997-01-01

    The intermetallic compound UPd 2 Sn has been shown in previous investigations to crystallize in an orthorhombic structure (space group Pnma). No indications for magnetic or superconducting transitions were found. However, if the Pd content is reduced, then, similar to UNi 2 Sn, a structural transition occurs. We prepared UPd 1.85 Sn and found it to crystallize as a Heusler compound in the MnCu 2 Al-structure (space group Fm anti 3m). Now the system undergoes a transition into a disordered magnetic state at T mag ≅ 28 K. Here, we present our measurements of the specific heat, susceptibility and muon relaxation of UPd 1.85 Sn, and discuss the nature of the magnetic state in relation to the crystallographic structure. (orig.)

  4. Growth and photovoltaic performance of SnS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Deepa, K.G., E-mail: deepachaithanya@gmail.com [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore (India); Nagaraju, J. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore (India)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Orthorhombic SnS quantum dots are synthesized by chemical method. Black-Right-Pointing-Pointer HOMO-LUMO level alignments confirmed the electron transport from SnS to TiO{sub 2}. Black-Right-Pointing-Pointer Cell characteristics are analyzed with different size quantum dots. Black-Right-Pointing-Pointer FF increased drastically from 15 to 51% on adding a buffer layer to the structure. Black-Right-Pointing-Pointer The SnS QDSSC showed highest V{sub oc} of 504 mV and 2.3 mA/cm{sup 2}. - Abstract: Tin sulphide (SnS) quantum dots of size ranging from 2.4 to 14.4 nm are prepared by chemical precipitation method in aqueous media. Growth of the SnS particles is monitored by controlling the deposition time. Both XRD and SAED patterns confirm that the particles possess orthorhombic structure. The uncapped SnS particles showed secondary phases like Sn{sub 2}S{sub 3} and SnS{sub 2} which is visible in the SAED pattern. From the electrochemical characterization, HOMO-LUMO levels of both TiO{sub 2} and SnS are determined and the band alignment is found to be favorable for electron transfer from SnS to TiO{sub 2}. Moreover, the HOMO-LUMO levels varied for different particle sizes. Solar cell is fabricated by sensitizing porous TiO{sub 2} thin film with SnS QDs. Cell structure is characterized with and without buffer layer between FTO and TiO{sub 2}. Without the buffer layer, cell showed an open circuit voltage (V{sub oc}) of 504 mV and short circuit current density (J{sub sc}) of 2.3 mA/cm{sup 2} under AM1.5 condition. The low fill factor of this structure (15%) is seen to be increased drastically to 51%, on the incorporation of the buffer layer. The cell characteristics are analyzed using two different size quantum dots.

  5. Structural and thermoelectric properties of the type-I Sn clathrates Cs8Sn46−n(n=0,2) from Density Functional Theory (DFT)

    KAUST Repository

    Egbele, Peter O.; Shoko, Elvis; Joubert, Daniel P.

    2018-01-01

    Sn clathrates are promising phonon glass, electron crystal materials (PGEC), in which the phonon free paths are short and the electron free paths are long. We analysed the relaxed structure of Sn clathrates using four different Density Funtional

  6. Mg{sub 2}Sn heterostructures on Si(111) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Dózsa, L., E-mail: dozsa@mfa.kfki.hu [Institute of Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, 1525 Budapest Pf, 49 (Hungary); Galkin, N.G. [Institute of Automation and Control Processes of FEB RAS, 5 Radio St., Vladivostok 690041 (Russian Federation); Far Eastern Federal University, 8 Sukhanova St., Vladivostok 690950 (Russian Federation); Pécz, B.; Osváth, Z.; Zolnai, Zs. [Institute of Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, 1525 Budapest Pf, 49 (Hungary); Németh, A. [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, 1525 Budapest, P.O.B. 49 (Hungary); Galkin, K.N.; Chernev, I.M. [Institute of Automation and Control Processes of FEB RAS, 5 Radio St., Vladivostok 690041 (Russian Federation); Dotsenko, S.A. [Institute of Automation and Control Processes of FEB RAS, 5 Radio St., Vladivostok 690041 (Russian Federation); Far Eastern Federal University, 8 Sukhanova St., Vladivostok 690950 (Russian Federation)

    2017-05-31

    Highlights: • Investigations show that the nanostructures have significant changes during the applied regular experimental investigations. • It is especially true for transmittance electron microscopy, where the investigated layers have to be thinned near to the nanostructure size. • The time order of the applied experimental investigation has a dominant effect on the experimetal results. - Abstract: Thin un-doped and Al doped polycrystalline Mg-stannide films consisting mainly of Mg{sub 2}Sn semiconductor phase have been grown by deposition of Sn-Mg multilayers on Si(111) p-type wafers at room temperature and annealing at 150 °C. Rutherford backscattering measurement spectroscopy (RBS) were used to determine the amount of Mg and Sn in the structures. Raman spectroscopy has shown the layers contain Mg{sub 2}Sn phase. Cross sectional transmission electron microscopy (XTEM) measurements have identified Mg{sub 2}Sn nanocrystallites in hexagonal and cubic phases without epitaxial orientation with respect to the Si(111) substrate. Significant oxygen concentration was found in the layer both by RBS and TEM. The electrical measurements have shown laterally homogeneous conductivity in the grown layer. The undoped Mg{sub 2}Sn layers show increasing resistivity with increasing temperature indicating the scattering process dominates the resistance of the layers, i.e. large concentration of point defects was generated in the layer during the growth process. The Al doped layer shows increase of the resistance at low temperature caused by freeze out of free carriers in the Al doped Mg{sub 2}Sn layer. The measurements indicate the necessity of protective layer grown over the Mg{sub 2}Sn layers, and a short time delay between sample preparation and cross sectionalTEM analysis, since the unprotected layer is degraded by the interaction with the ambient.

  7. Quality control for a group of pyrophosphate-Sn kits

    International Nuclear Information System (INIS)

    Isaac, M.; Gamboa, R.; Hernandez, I.; Leyva, R.; Turino, D.

    1994-01-01

    The quality control for a group of Pyrophosphate-Sn kits for labeling with 99 m Tc is carry out at the Isotope Center. A general discussion takes place about the instrumental techniques for the determination of the kit constituent such as ligands, Sn(II), water, etc, as well as the control table for the evaluation of the warranty time. (author). 5 refs, 4 figs

  8. Magnetic properties of Np2T2Sn compounds

    International Nuclear Information System (INIS)

    Sanchez, J.P.; Colineau, E.; Jeandey, C.; Oddou, J.L.; Rebizant, J.; Seret, A.; Spirlet, J.C.

    1994-01-01

    The magnetic properties of the Np 2 T 2 Sn series investigated by 237 Np Moessbauer spectroscopy are reported. Magnetic ordering is shown to occur for T = Ni, Pd, Pt, whereas the Np ions do not carry a local moment when T = Co, Ru, Rh. Comparison is made with the corresponding Np 2 T 2 In and U 2 T 2 Sn compounds. (authors). 5 refs., 3 figs

  9. Few-valence-particle excitations around doubly magic 132Sn

    International Nuclear Information System (INIS)

    Daly, P.J.; Zhang, C.T.; Bhattacharyya, P.

    1996-01-01

    Prompt γ-ray cascades in neutron-rich nuclei around doubly-magic 132 Sn have been studied using a 248 Cm fission source. Yrast states located in the N = 82 isotones 134 Te and 135 I are interpreted as valence proton and neutron particle-hole core excitations with the help of shell model calculations employing empirical nucleon-nucleon interactions from both 132 Sn and 208 Pb regions

  10. Interface between Sn-Sb-Cu solder and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sebo, P., E-mail: Pavel.Sebo@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Svec, P. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janickovic, D.; Illekova, E. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine)

    2011-07-15

    Highlights: {yields} New lead-free solder materials based on Sn-Sb-Cu were designed and prepared. {yields} Melting and solidification temperatures of the solders have been determined. {yields} Cu-substrate/solder interaction has been analyzed and quantified. {yields} Phases formed at the solder-substrate interface have been identified. {yields} Composition and soldering atmospheres were correlated with joint strength. - Abstract: Influence of antimony and copper in Sn-Sb-Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu-solder-Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere - air with the flux and deoxidising N{sub 2} + 10H{sub 2} gas - was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} phases arise. Cu{sub 3}Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu{sub 6}Sn{sub 5} phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

  11. Electrochemical fabrication of Sn nanowires on titania nanotube guide layers

    International Nuclear Information System (INIS)

    Djenizian, Thierry; Hanzu, Ilie; Premchand, Yesudas D; Vacandio, Florence; Knauth, Philippe

    2008-01-01

    We describe a novel approach for the fabrication of tailored nanowires using a two-step electrochemical process. It is demonstrated that self-organized TiO 2 nanotubes can be used to activate and guide the electrochemical growth of Sn crystallites, leading to the formation of vertical features with a high aspect ratio. We show that the dimensions and the density of Sn crystallites depend on the electrodeposition parameters

  12. Supernova mechanisms: Before and after SN1987a

    International Nuclear Information System (INIS)

    Kahana, S.H.

    1987-01-01

    The impact of SN1987a on theoretical studies of the specific mechanism generating Type II supernovae is examined. The explosion energy extracted from analysis of the light curve for SN 1987a is on the edge of distinguishing between a prompt explosion from a hydrodynamic shock and a delayed, neutrino-induced, explosion. The detection of neutrinos from 1987a is also reanalyzed. 30 refs., 2 tabs

  13. Modifications in SnS thin films by plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Avellaneda, D. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico)

    2012-02-01

    The present study shows the modifications of structural, optical and electrical characteristics that occur in tin sulfide (SnS) thin films treated in air and in nitrogen plasma at different pressure conditions. The films were obtained by the chemical bath deposition method, which results in SnS thin films with an orthorhombic crystalline structure, band gap (E{sub g}) of 1.1-1.2 eV, and electrical conductivities ({sigma}) in the order of 10{sup -6} {Omega}{sup -1}cm{sup -1}. The films treated with air plasma at pressures between 1 and 4 Torr, showed the presence of SnS{sub 2}, Sn{sub 2}S{sub 3}, and SnO{sub 2} phases, within the band gap values ranging from 0.9 to 1.5 eV. On the other hand, the films treated with nitrogen plasma presented the same phases, but showed a significant modification in the electrical conductivity, increasing from 10{sup -6} {Omega}{sup -1}cm{sup -1} (as-deposited) up to 10{sup -2}-10{sup -3} {Omega}{sup -1}cm{sup -1} (plasma treated). This result is a suitable range of conductivity for the improvement of the solar cells with SnS as an absorber material. Also, emission spectroscopy measurements were carried out in both air and nitrogen plasma treatments.

  14. Multifilamentary Cu-Nb3Sn superconductor wires

    International Nuclear Information System (INIS)

    Rodrigues, D.; Pinatti, D.G.

    1990-01-01

    This paper reports on one of the main technological problems concerning Nb 3 Sn superconducting wires production which is the optimization of heat treatments for the formation of the A-15 intermetallic compound. At the present work, Nb 3 Sn superconducting wire is produced by solid-liquid diffusion method which increases considerably the critical current values of the superconductor. Through this method, niobium, copper and Sn 7% wt Cu alloy are kept in the pure state. Thus, the method dispenses intermediate heat treatments of recrystallization during the manufacturing process of the wire. After the wire was ready, optimization work of heat treatments was accomplished aiming to obtain its best superconducting characteristics, Measurement of critical temperature, critical current versus magnetic field, normal and at room temperature resistivity were performed, as well as scanning electron microscopy for determination of Nb 3 Sn layers and transmission electron microscopy measurements of redetermining the grain sizes in Nb 3 Sn formed in each treatment. It was obtained critical current densities of 1.8 x 10 6 A/cm 2 in the Nb 3 Sn layer, at 10 Teslas and 4.2 K. The samples were analyzed by employing the superconducting collective flux pinning theories and a satisfactory agreement between the experimental and theoretical data was attained. The production process and the small size of the filaments used made a successful optimization of the wire possible

  15. Portuguese granites associated with Sn-W and Au mineralizations

    Directory of Open Access Journals (Sweden)

    Ana M.R. Neiva

    2002-01-01

    Full Text Available In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional crystallization. Greisenizations of two-mica S-type granites associated with tin-tungsten mineralizations are accompanied by an increase in SiO2, H2O+, Sn, W, Nb, Ta, Rb, Zn, and Pb and decrease in MgO, Na2O, V, Sc,Zr, and Sr. The granite associated with the Jales gold deposit is of S-type and strongly differentiated like the tin-bearing S-type granites, but it has a very low Sn content. During fractional crystallization, Si, Rb, Sn, Pb, Au, As, Sb, and S increase. During increasing degree of hydrothermal alteration of this granite at the gold-quartz vein walls, there are progressive increases in K2O, H2O+, Sn, Cs, Cu, Pb, Au, Sb, As, and S.

  16. Enthalpy of mixing of liquid Co–Sn alloys

    International Nuclear Information System (INIS)

    Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

    2014-01-01

    Highlights: • The enthalpies of mixing of liquid Co–Sn alloys between T = (673 and 1773) K. • The temperature dependence of the enthalpies of mixing was described. • Full report of measured values including polynomial coefficients. - Abstract: A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process

  17. 51Cr diffusion in Zr-Sn alloys

    International Nuclear Information System (INIS)

    Nicolai, L.I.; Migoni, R.L.; Hojvat de Tendler, Ruth

    1982-01-01

    The 51 Cr volume diffusion in Zr-Sn alloys is measured in polycrystals with big grains by the thin-film method. The Sn content in the alloys ranges from 0.39% at to 6.66 % at. In the beta-phase the analysed temperature range is 982 deg C-1240 deg C. The Sn dehances the 51 Cr diffusion in beta-Zr, the effect being small but well defined. Assuming the formation of Sn-Cr dimers, the linear dehancement coefficient b and the parameters for the variation of b with temperature were calculated. The parameters Q and D o were calculated for the more diluted alloys and, upon application of the Zener theory for D o , a negative contribution to the activation entropy is found. Three experiments at different temperatures were performed in the alpha-phase. 51 Cr diffuses very fast in alpha-Zr-Sn. No definite correlation is found between the 51 Cr diffusivity and the increasing Sn concentration, probably due to the anisotropy of the alfa-phase. (M.E.L.) [es

  18. 119Sn MAS NMR Study of Probe Molecules Interaction with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation

    DEFF Research Database (Denmark)

    Yakimov, Alexander V.; G. Kolyagin, Yury; Tolborg, Søren

    2016-01-01

    and weak Lewis acidity, respectively. The adsorption of acetonitrile and methanol resulted in observation of pentacoordinated tin species, due to the formation of 1:1 adsorption complexes over both Sn-sites. Water adsorption led first to formation of pentacoordinated tin species, which were further...... by the formation of pentacoordinated Sn species in the case of weak sites and hexacoordinated Sn over sites with strong Lewis acidity, pointing to the possibility of dissociative adsorption of secondary alcohols over strong Sn-sites....

  19. Electrochemical energy storage behavior of Sn/SnO2 double phase nanocomposite anodes produced on the multiwalled carbon nanotube buckypapers for lithium-ion batteries

    Science.gov (United States)

    Alaf, Mirac; Akbulut, Hatem

    2014-02-01

    Recent development of electrode materials for Li-ion batteries is driven mainly by hybrid nanocomposite structures consisting of Li storage compounds and CNTs. In this study, tin/tinoxide (Sn/SnO2) films and tin/tinoxide/multi walled carbon nanotube (Sn/SnO2/MWCNT) nanocomposites are produced by a two steps process; thermal evaporation and subsequent plasma oxidation as anode materials for Li-ion batteries. The physical, structural, and electrochemical behaviors of the nanocomposite electrodes containing MWCNTs are discussed. The ratio between metallic tin (Sn) and tinoxide (SnO2) is controlled with plasma oxidation time and effects of the ratio are investigated on the structural and electrochemical properties. The greatly enhanced electrochemical performance is mainly due to the morphological stability and reduced diffusion resistance, which are induced by MWCNT core and deposited Sn/SnO2 double phase shell. The outstanding long-term cycling stability is a result of the two layers Sn and SnO2 phases on MWCNTs. The nanoscale Sn/SnO2/MWCNT network provides good electrical conductivity, and the creation of open spaces that buffer a large volume change during the Li-alloying/de-alloying reaction.

  20. Sandwich-like C@SnO2/Sn/void@C hollow spheres as improved anode materials for lithium ion batteries

    Science.gov (United States)

    Wang, Huijun; Jiang, Xinya; Chai, Yaqin; Yang, Xia; Yuan, Ruo

    2018-03-01

    As lithium ion batteries (LIBs) anode, SnO2 suffers fast capacity fading due to its large volume expansion during discharge/charge process. To overcome the problem, sandwich-like C@SnO2/Sn/void@C hollow spheres (referred as C@SnO2/Sn/void@C HSs) are prepared by in-situ polymerization and carbonization, using hollow SnO2 as self-template and dopamine as carbon source. The C@SnO2/Sn/void@C HSs possesses the merits of hollow and core/void/shell structure, so that they can accommodate the volume change under discharge/charge process, shorten the transmission distance of Li ions, own more contact area for the electrolyte. Thanks to these advantages, C@SnO2/Sn/void@C HSs display excellent electrochemical performance as anode materials for LIBs, which deliver a high capacity of 786.7 mAh g-1 at the current density of 0.5 A g-1 after 60 cycles. The simple synthesis method for C@SnO2/Sn/void@C HSs with special structure will provide a promising method for preparing other anode materials for LIBs.

  1. VAMAS Nb3Sn test conductor

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    A bronze-process Nb 3 Sn conductor was measured as part of the second VAMAS (Versailles Project on Advanced Materials and Standards) international critical-current round robin. The conductor specifications are given in Table 15. The critical current was measured as a function of magnetic field and axial tensile strain. The measured data are presented in Table 16 and in Figs. 23 and 24. The I c and J c values are based on an electric field criterion (E c ) of 1 μV/cm. In the first VAMAS round robin tests, differences in the test specimens' axial strain, caused by variations in the thermal contraction of different test fixtures, was a major source of interlaboratory variation in the critical-current data. Consequently, electromechanical characterization of the test specimen is important for data interpretation and error analysis. In the second round robin, the test apparatus and procedure were more rigidly specified. This increased experimental control reduced the critical-current variation by a factor of 3.5. The results of our measurements will be published in the final VAMAS report

  2. Constraining cosmological parameter with SN Ia

    International Nuclear Information System (INIS)

    Putri, A N Indra; Wulandari, H R Tri

    2016-01-01

    A type I supemovae (SN Ia) is an exploding white dwarf, whose mass exceeds Chandrasekar limit (1.44 solar mass). If a white dwarf is in a binary system, it may accrete matter from the companion, resulting in an excess mass that cannot be balanced by the pressure of degenerated electrons in the core. SNe Ia are highly luminous objects, that they are visible from very high distances. After some corrections (stretch (s), colour (c), K-corrections, etc.), the variations in the light curves of SNe Ia can be suppressed to be no more than 10%. Their high luminosity and almost uniform intrinsic brightness at the peak light, i.e. M B ∼ -19, make SNe Ia ideal standard candle. Because of their visibility from large distances, SNe Ia can be employed as a cosmological measuring tool. It was analysis of SNe Ia data that indicated for the first time, that the universe is not only expanding, but also accelerating. This work analyzed a compilation of SNe Ia data to determine several cosmological parameters (H 0 , Ω m , Ω a , and w ). It can be concluded from the analysis, that our universe is a flat, dark energy dominated universe, and that the cosmological constant A is a suitable candidate for dark energy. (paper)

  3. Interpretation of neutrinos from SN1987a

    International Nuclear Information System (INIS)

    Lattimer, J.M.

    1987-01-01

    The neutrinos from SN1987a detected by Kamiokande II and IMB are analyzed. Bounds on the average (anti)neutrino energy and on the total emitted neutrino energy are derived. Comparison is made with the neutron star birth models of Burrows and Lattimer. Care is taken to include the individual detector characteristics, and various statistical analyses of the data and the detector background are performed. Some of the conclusions reached are: there is little statistical significance to the bunching in the observed timing of the neutrinos- the data are consistent with an exponential or power-law decay of the source luminosity. There is evidence that the rate of decrease of the decay decreases with time, as anticipated in their models. The long duration of the signal is also to be expected, due to the diffusion of the neutrinos from the newly formed neutron star. An upper bound on the neutrino rest mass, of order 6 eV, is derived, using a minimum of physically reasonable assumptions

  4. Magnetic susceptibility measurements on Bi - Sn alloys

    International Nuclear Information System (INIS)

    Mustaffa bin Haji Abdullah

    1985-01-01

    Magnetic susceptibility measurements on eight samples of tin-rich and three samples of bismuth-rich Bi-Sn alloys were made from 85K to 300K by Faraday's method. The susceptibilities of the eight tin-rich samples are positive and greater than the susceptibility of pure tin. The values are approximately constant at low temperatures but decreasing a little bit with increasing temperature. This result is interpreted as due to the predominant contribution of the Pauli spin paramagnetic susceptibility. A small decrease in susceptibility with temperature is interpreted as due to the effect of the second order term in the expression for spin paramagnetic susceptibility. The fluctuation of the susceptibility for alloys of different composition is interpreted as due to the effect of the density of states at the Fermi levels. The three samples of bismuth-rich alloys show a transition to diamagnetic property, where the diamagnetism is increased with temperature. This result is predominant and due to the diamagnetic contribution from the ions. The increase in susceptibility with temperature is interpreted as due to an increase in the effective radii of the ions due to thermal expansion. (author)

  5. Study of intruder band in 112Sn

    International Nuclear Information System (INIS)

    Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Bhattacharya, S.; Saha-Sarkar, M.; Goswami, A.; Mukhopadhyay, S.; Mukherjee, A.; Mukherjee, G.; Basu, S.K.

    2007-01-01

    Excited states of the positive-parity intruder band in 112 Sn, populated in the 100 Mo( 20 Ne,α4n) reaction at a beam energy of 136 MeV, have been studied. The band has been observed up to 11570.0 keV with spin (24 + ). Mean lifetimes have been measured for six states up to the 22 + , 10335.1 keV level and an upper limit of the lifetime has been estimated for the 11570.0 keV (24 + ) state. The B(E2) values, derived from the present lifetime results, correspond to a moderate quadrupole deformation of β 2 ∼0.18 for states with spin J π >=12 + , and the decrease in B(E2) for the 14 + ->12 + transition is consistent with a ν(h 11/2 ) 2 alignment at ω∼0.35 MeV, predicted by a cranked shell-model calculation. Total Routhian surface calculations predict a triaxial shape following the alignment

  6. Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

    Science.gov (United States)

    Jerkstrand, A.; Ergon, M.; Smartt, S. J.; Fransson, C.; Sollerman, J.; Taubenberger, S.; Bersten, M.; Spyromilio, J.

    2015-01-01

    We investigate line formation processes in Type IIb supernovae (SNe) from 100 to 500 days post-explosion using spectral synthesis calculations. The modelling identifies the nuclear burning layers and physical mechanisms that produce the major emission lines, and the diagnostic potential of these. We compare the model calculations with data on the three best observed Type IIb SNe to-date - SN 1993J, SN 2008ax, and SN 2011dh. Oxygen nucleosynthesis depends sensitively on the main-sequence mass of the star and modelling of the [O I] λλ6300, 6364 lines constrains the progenitors of these three SNe to the MZAMS = 12-16 M⊙ range (ejected oxygen masses 0.3-0.9 M⊙), with SN 2011dh towards the lower end and SN 1993J towards the upper end of the range. The high ejecta masses from MZAMS ≳ 17 M⊙ progenitors give rise to brighter nebular phase emission lines than observed. Nucleosynthesis analysis thus supports a scenario of low-to-moderate mass progenitors for Type IIb SNe, and by implication an origin in binary systems. We demonstrate how oxygen and magnesium recombination lines may be combined to diagnose the magnesium mass in the SN ejecta. For SN 2011dh, a magnesium mass of 0.02-0.14 M⊙ is derived, which gives a Mg/O production ratio consistent with the solar value. Nitrogen left in the He envelope from CNO burning gives strong [N II] λλ6548, 6583 emission lines that dominate over Hα emission in our models. The hydrogen envelopes of Type IIb SNe are too small and dilute to produce any noticeable Hα emission or absorption after ~150 days, and nebular phase emission seen around 6550 Å is in many cases likely caused by [N II] λλ6548, 6583. Finally, the influence of radiative transport on the emergent line profiles is investigated. Significant line blocking in the metal core remains for several hundred days, which affects the emergent spectrum. These radiative transfer effects lead to early-time blueshifts of the emission line peaks, which gradually

  7. Nano-grain SnO{sub 2} electrodes for high conversion efficiency SnO{sub 2}-DSSC

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung-Hoon; Shin, Yu-Ju [Department of Chemistry, the Catholic University of Korea, Bucheon, Gyeonggi-do 422-743 (Korea, Republic of); Park, Nam-Gyu [School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2011-01-15

    The nano-grain ZnO/SnO{sub 2} composite electrode was prepared by adding 5 w% of the 200-250 nm ZnO particles to the 5 nm SnO{sub 2} colloid in the presence of hydroxypropylcellulose (M.W.=80,000). The nano-grain SnO{sub 2} electrode was obtained by removing the ZnO particles from the composite electrode using acetic acid. The FE-SEM micrographs revealed that both electrodes consisted of interconnected nano-grains that were ca. 800 nm in size, and the large pores between the grains furnished the wide electrolyte diffusion channels within the electrodes. The photovoltaic properties of the nano-grain electrodes were investigated by measuring the I-V behaviors, the IPCE spectra and the ac-impedance spectra. The nano-grain electrodes exhibited remarkably improved conversion efficiencies of 3.96% for the composite and 2.98% for the SnO{sub 2} electrode compared to the value of 1.66% for the usual nano-particle SnO{sub 2} electrode. The improvement conversion efficiencies were mainly attributed to the formation of nano-grains, which facilitated the electron diffusion within the grains. The improved electrolyte diffusion as well as the light-scattering effects enhanced the photovoltaic performance of the SnO{sub 2} electrode. (author)

  8. Identify and Quantify the Mechanistic Sources of Sensor Performance Variation Between Individual Sensors SN1 and SN2

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baldwin, David L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cinson, Anthony D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Anthony M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Larche, Michael R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mathews, Royce [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mullen, Crystal A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pardini, Allan F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Posakony, Gerald J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Prowant, Matthew S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hartman, Trenton S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Edwards, Matthew K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-08-06

    This Technical Letter Report satisfies the M3AR-14PN2301022 milestone, and is focused on identifying and quantifying the mechanistic sources of sensor performance variation between individual 22-element, linear phased-array sensor prototypes, SN1 and SN2. This effort constitutes an iterative evolution that supports the longer term goal of producing and demonstrating a pre-manufacturing prototype ultrasonic probe that possesses the fundamental performance characteristics necessary to enable the development of a high-temperature sodium-cooled fast reactor inspection system. The scope of the work for this portion of the PNNL effort conducted in FY14 includes performing a comparative evaluation and assessment of the performance characteristics of the SN1 and SN2 22 element PA-UT probes manufactured at PNNL. Key transducer performance parameters, such as sound field dimensions, resolution capabilities, frequency response, and bandwidth are used as a metric for the comparative evaluation and assessment of the SN1 and SN2 engineering test units.

  9. Li2SnO3 derived secondary Li-Sn alloy electrode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, D.W.; Zhang, S.Q.; Jin, Y.; Yi, T.H.; Xie, S.; Chen, C.H.

    2006-01-01

    As a possible high-capacity Li-ion battery anode material, Li 2 SnO 3 was prepared via a solid-state reaction route and a sol-gel route, separately. Its electrochemical performance was tested in coin-type cells with metallic Li as the counter electrode. The results show that the sol-gel derived Li 2 SnO 3 has uniform nano-sized particles (200-300 nm) and can deliver a better reversible capacity (380 mAh/g after 50 cycles in the voltage window of 0-1 V) than that from the solid-state reaction route. The characterizations by means of galvanostatic cycling, cyclic voltammetry and ex situ X-ray diffraction indicate that the electrochemical process of the Li 2 SnO 3 lithiation proceeds with an initial structural reduction of the composite oxide into Sn-metal and Li 2 O followed by a reversible Li-Sn alloy formation in the Li 2 O matrix. Due to the buffer role of the Li 2 O matrix, the reversibility of the secondary Li-Sn alloy electrode is largely secured

  10. Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

    2009-05-27

    The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

  11. Phase Equilibria of the Sn-Ni-Si Ternary System and Interfacial Reactions in Sn-(Cu)/Ni-Si Couples

    Science.gov (United States)

    Fang, Gu; Chen, Chih-chi

    2015-07-01

    Interfacial reactions in Sn/Ni-4.5 wt.%Si and Sn-Cu/Ni-4.5 wt.%Si couples at 250°C, and Sn-Ni-Si ternary phase equilibria at 250°C were investigated in this study. Ni-Si alloys, which are nonmagnetic, can be regarded as a diffusion barrier layer material in flip chip packaging. Solder/Ni-4.5 wt.%Si interfacial reactions are crucial to the reliability of soldered joints. Phase equilibria information is essential for development of solder/Ni-Si materials. No ternary compound is present in the Sn-Ni-Si ternary system at 250°C. Extended solubility of Si in the phases Ni3Sn2 and Ni3Sn is 3.8 and 6.1 at.%, respectively. As more Si dissolves in these phases their lattice constants decrease. No noticeable ternary solubility is observed for the other intermetallics. Interfacial reactions in solder/Ni-4.5 wt.%Si are similar to those for solder/Ni. Si does not alter the reaction phases. No Si solubility in the reaction phases was detected, although rates of growth of the reaction phases were reduced. Because the alloy Ni-4.5 wt.%Si reacts more slowly with solders than pure Ni, the Ni-4.5 wt.%Si alloy could be a potential new diffusion barrier layer material for flip chip packaging.

  12. Improving cycle stability of SnS anode for sodium-ion batteries by limiting Sn agglomeration

    Science.gov (United States)

    Wang, Wenhui; Shi, Liang; Lan, Danni; Li, Quan

    2018-02-01

    Flower-like SnS nanostructures are obtained by a simple solvothermal method for anode applications in Na-ion batteries. We show experimental evidence of progressive Sn agglomeration and crystalline Na2S enrichment at the end of de-sodiation process of the SnS electrode, both of which contribute to the capacity decay of the electrode upon repeated cycles. By replacing the commonly adopted acetylene black conductive additive with multi-wall carbon nanotubes (MWCNT), the cycle stability of the SnS electrode is largely improved, which correlates well with the observed suppression of both Sn agglomeration and Na2S enrichment at the end of de-sodiation cycle. A full cell is assembled with the SnS/MWCNT anode and the P2-Na2/3Ni1/3Mn1/2Ti1/6O2 cathode. An initial energy density of 262 Wh/kg (normalized to the total mass of cathode and anode) is demonstrated for the full cell, which retains 71% of the first discharge capacity after 40 cycles.

  13. Cluster-derived Ir-Sn/SiO2 catalysts for the catalytic dehydrogenation of propane: A spectroscopic study

    KAUST Repository

    Gallo, Alessandro; Psaro, Rinaldo; Guidotti, Matteo; Dal Santo, Vladimiro; Pergola, Roberto Della; Masih, Dilshad; Izumi, Yasuo

    2013-01-01

    Ir-Sn bimetallic silica-based materials have been prepared via deposition of the molecular organometallic clusters (NEt4)2[Ir 4(CO)10(SnCl3)2] and NEt 4[Ir6(CO)15(SnCl3)] or via deposition of Sn organometallic precursor Sn(n-C4H9) 4 onto pre

  14. Conduction-type control of SnSx films prepared by the sol–gel method for different sulfur contents

    International Nuclear Information System (INIS)

    Huang, Chung-Cheng; Lin, Yow-Jon; Chuang, Cheng-Yu; Liu, Chia-Jyi; Yang, Yao-Wei

    2013-01-01

    Highlights: ► The effect of S content on the electrical property of the SnS x film was examined. ► For S-rich films, the probability of having formed Sn vacancies (V Sn ) should be high. ► Transformation from V Sn to V Sn 2- is accompanied by lattice relaxation. ► Transformation from Sn 2+ to Sn 4+ is an offset to lattice relaxation. ► A link between the conduction type and defects was established. -- Abstract: The effect of S content on the electrical property of the sol–gel SnS x films was examined. The observed conduction-type changes are related to the different ratios between the concentrations of Sn 4+ and Sn 2+ . The experimental identification confirms that n-type conversion is due to an increase in the atomic concentration ratio of Sn 4+ /(Sn 4+ + Sn 2+ ) in the S-rich film. The probability of having formed Sn vacancies (V Sn ) should be high under S-rich growth conditions. Transformation from V Sn to V Sn 2- is accompanied by lattice relaxation. Therefore, transformation from Sn 2+ to Sn 4+ is an offset to lattice relaxation under S-rich growth conditions, increasing the electron density and producing n-type conversion. A suitable sulfur concentration is an important issue for tuning conduction type of SnS x

  15. Graphene-SnO2 composites for highly efficient photocatalytic degradation of methylene blue under sunlight.

    Science.gov (United States)

    Seema, Humaira; Christian Kemp, K; Chandra, Vimlesh; Kim, Kwang S

    2012-09-07

    Graphene sheets decorated with SnO(2) nanoparticles (RGO-SnO(2)) were prepared via a redox reaction between graphene oxide (GO) and SnCl(2). Graphene oxide (GO) was reduced to graphene (RGO) and Sn(2+) was oxidized to SnO(2) during the redox reaction, leading to a homogeneous distribution of SnO(2) nanoparticles on RGO sheets. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show uniform distribution of the nanoparticles on the RGO surface and high-resolution transmission electron microscopy (HRTEM) shows an average particle size of 3-5 nm. The RGO-SnO(2) composite showed an enhanced photocatalytic degradation activity for the organic dye methylene blue under sunlight compared to bare SnO(2) nanoparticles. This result leads us to believe that the RGO-SnO(2) composite could be used in catalytic photodegradation of other organic dyes.

  16. Pressure dependence of magnetic ordering temperatures of rare earth-Sn/sub 3/ compounds

    Energy Technology Data Exchange (ETDEWEB)

    Foner, S [Massachusetts Inst. of Tech., Cambridge (USA). Francis Bitter National Magnet Lab.

    1979-12-01

    Measurements of the hydrostatic pressure dependence of the Neel temperatures, Tsub(N), are reported for PrSn/sub 3/, NdSn/sub 3/, GdSn/sub 3/ and CeIn/sub 3/. Tsub(N) is found to increase with applied pressure for PrSn/sub 3/ and NdSn/sub 3/, whereas Tsub(N) is pressure independent within experimental error for GdSn/sub 3/ and CeIn/sub 3/. Slightly Sn-deficient RESn/sub 3/ (RE = rare earth) compounds are found consistently to be weakly ferromagnetic. The physical properties of the RESn/sub 3/ compounds exhibit analogies with the corresponding properties of dilute superconducting (LaRE)Sn/sub 3/ alloys. The high pressure data for PrSn/sub 3/ and CeIn/sub 3/ are qualitatively consistent with a 'Kondo necklace' model for magnetically ordered RE compounds with unstable 4f shells.

  17. Pressure dependence of magnetic ordering temperatures of rare earth - Sn/sub 3/ compounds

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, L E [Virginia Univ., Charlottesville (USA). Dept. of Physics; Guertin, R P; Foner, S

    1979-12-01

    Measurements of the hydrostatic pressure dependence of the Neel temperatures, Tsub(N), are reported for PrSn/sub 3/, NdSn/sub 3/, GdSn/sub 3/ and CeIn/sub 3/. Tsub(N) is found to increase with applied pressure for PrSn/sub 3/ and NdSn/sub 3/, whereas Tsub(N) is pressure independent within experimental error for GdSn/sub 3/ and CeIn/sub 3/. Slightly Sn-deficient RESn/sub 3/ (RE=rare earth) compounds are found consistently to be weakly ferromagnetic. The physical properties of the RESn/sub 3/ compounds exhibit analogies with the corresponding properties of dilute superconducting (LaRE)Sn/sub 3/ alloys. The high pressure data for PrSn/sub 3/ and CeIn/sub 3/ are qualitatively consistent with a 'Kondo necklace' model for magnetically ordered RE compounds with unstable 4f shells.

  18. Enhanced hydrogen storage capacity of Ni/Sn-coated MWCNT nanocomposites

    Science.gov (United States)

    Varshoy, Shokufeh; Khoshnevisan, Bahram; Behpour, Mohsen

    2018-02-01

    The hydrogen storage capacity of Ni-Sn, Ni-Sn/multi-walled carbon nanotube (MWCNT) and Ni/Sn-coated MWCNT electrodes was investigated by using a chronopotentiometry method. The Sn layer was electrochemically deposited inside pores of nanoscale Ni foam. The MWCNTs were put on the Ni-Sn foam with nanoscale porosities using an electrophoretic deposition method and coated with Sn nanoparticles by an electroplating process. X-ray diffraction and energy dispersive spectroscopy results indicated that the Sn layer and MWCNTs are successfully deposited on the surface of Ni substrate. On the other hand, a field-emission scanning electron microscopy technique revealed the morphology of resulting Ni foam, Ni-Sn and Ni-Sn/MWCNT electrodes. In order to measure the hydrogen adsorption performed in a three electrode cell, the Ni-Sn, Ni-Sn/MWCNT and Ni/Sn-coated MWCNT electrodes were used as working electrodes whereas Pt and Ag/AgCl electrodes were employed as counter and reference electrodes, respectively. Our results on the discharge capacity in different electrodes represent that the Ni/Sn-coated MWCNT has a maximum discharge capacity of ˜30 000 mAh g-1 for 20 cycles compared to that of Ni-Sn/MWCNT electrodes for 15 cycles (˜9500 mAh g-1). By increasing the number of cycles in a constant current, the corresponding capacity increases, thereby reaching a constant amount for 20 cycles.

  19. Syntheses, structural variants and characterization of AInM′S4 (A=alkali metals, Tl; M′ = Ge, Sn) compounds; facile ion-exchange reactions of layered NaInSnS4 and KInSnS4 compounds

    International Nuclear Information System (INIS)

    Yohannan, Jinu P.; Vidyasagar, Kanamaluru

    2016-01-01

    Ten AInM′S 4 (A=alkali metals, Tl; M′= Ge, Sn) compounds with diverse structure types have been synthesized and characterized by single crystal and powder X-ray diffraction and a variety of spectroscopic methods. They are wide band gap semiconductors. KInGeS 4 (1-β), RbInGeS 4 (2), CsInGeS 4 (3-β), TlInGeS 4 (4-β), RbInSnS 4 (8-β) and CsInSnS 4 (9) compounds with three-dimensional BaGa 2 S 4 structure and CsInGeS 4 (3-α) and TlInGeS 4 (4-α) compounds with a layered TlInSiS 4 structure have tetrahedral [InM′S 4 ] − frameworks. On the other hand, LiInSnS 4 (5) with spinel structure and NaInSnS 4 (6), KInSnS 4 (7), RbInSnS 4 (8-α) and TlInSnS 4 (10) compounds with layered structure have octahedral [InM′S 4 ] − frameworks. NaInSnS 4 (6) and KInSnS 4 (7) compounds undergo facile topotactic ion-exchange, at room temperature, with various mono-, di- and tri-valent cations in aqueous medium to give rise to metastable layered phases. - Graphical abstract: NaInSnS 4 and KInSnS 4 compounds undergo, in aqueous medium at room temperature, facile topotactic ion-exchange with mono, di and trivalent cations. Display Omitted - Highlights: • Ten AInM′S 4 compounds with diverse structure types were synthesized. • They are wide band gap semiconductors. • NaInSnS 4 and KInSnS 4 compounds undergo facile topotactic ion-exchange at room temperature.

  20. Synthesis of Pt{sub 75}Sn{sub 25}/SnO{sub 2}/CNT nanoscaled electrode: Low onset potential of ethanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Tabet-Aoul, Amel [Institut National de la Recherche Scientifique (INRS)-Énergie, Matériaux et Télécommunications (EMT), 1650 Boulevard Lionel Boulet, Varennes, Québec, Canada J3X 1S2 (Canada); Mohamedi, Mohamed, E-mail: mohamedi@emt.inrs.ca [Institut National de la Recherche Scientifique (INRS)-Énergie, Matériaux et Télécommunications (EMT), 1650 Boulevard Lionel Boulet, Varennes, Québec, Canada J3X 1S2 (Canada)

    2013-03-15

    Highlights: ► A pulsed laser synthesis is used for the deposition of Pt, SnO{sub 2} and PtSn alloy thin films onto carbon nanotubes. ► These nanoscaled materials were characterized by FESEM, TEM, XRD and XPS. ► Enhanced electrocatalytic properties toward ethanol oxidation. -- Abstract: With the objective of lowering the potential oxidation of ethanol at PtSn nanocatalyst, we present the synthesis of free-standing catalyst layer comprising a current collector/carbon nanotubes (catalyst support)/SnO{sub 2}/Pt{sub 75}Sn{sub 25} (catalyst) nanostructured layers, each layer constructed upon the one below it. The CNTs are grown by chemical vapor deposition (CVD), whereas SnO{sub 2} and Pt{sub 75}Sn{sub 25} are synthesized by pulsed laser deposition and cross-beam laser deposition, respectively. FESEM revealed that Pt{sub 75}Sn{sub 25} nanoparticles assemble into cauliflower-like arrangement. TEM and HR-TEM showed that the Pt{sub 75}Sn{sub 25} layer thickness is of ca. 25 nm with a particle mean diameter of 4.3 nm. It was found that addition of SnO{sub 2} to Pt{sub 75}Sn{sub 25} promotes significantly the oxidation of ethanol at Pt{sub 75}Sn{sub 25} nanoparticles relative to a carbon nanotubes support. Indeed, the electrooxidation of ethanol at CNTs/SnO{sub 2}/Pt{sub 75}Sn{sub 25} electrode starts at about 100 mV negative with respect to that at CNT/Pt{sub 75}Sn{sub 25}. This decreased overpotential required to oxidize ethanol is very significant and has profound implications to developing high performing anodes for direct ethanol fuel cells technology.

  1. The Incredibly Long-Lived SN 2005ip

    Science.gov (United States)

    Fox, Ori

    2016-10-01

    Type IIn supernovae (SNe IIn) are defined by their relatively narrow spectral line features associated with a dense circumstellar medium (CSM) formed by the progenitor star. The nature of the progenitor and mass loss remains relatively unknown. Shock interaction with the dense CSM can often result in significant UV emission for several years post-explosion, thereby probing the CSM characteristics, progenitor mass loss history and, ultimately, the progenitor itself. The Type IIn SN 2005ip proves to be one of the most interesting and well-studied targets within this subclass. Compared to all other supernovae, SN 2005ip is the most luminous for its age. Now more than 11 years post-explosion, the SN has released >10^51 erg throughout its lifetime as the forward shock continues to collide with a dense CSM. Here we propose HST/STIS-MAMA UV observations of SN 2005ip to investigate the massive CSM. When accounting for the shock travel time, these observations will probe material lost from the progenitor more than 1000 years prior to the explosion. We already have a single HST/STIS spectrum of SN 2005ip from 2014, which was obtained while the shock was still within a higher mass regime. With just 5 orbits, a second spectrum will allow us to directly trace the evolution of the CSM and produce new constraints on the pre-SN mass-loss history. Coinciding with Cycle 24's UV Initiative, this program offers new insight regarding both the progenitor and explosion characteristics of the SN IIn subclass.

  2. Lattice positions of Sn in Cu2ZnSnS4 nanoparticles and thin films studied by synchrotron X-ray absorption near edge structure analysis

    Science.gov (United States)

    Zillner, E.; Paul, A.; Jutimoosik, J.; Chandarak, S.; Monnor, T.; Rujirawat, S.; Yimnirun, R.; Lin, X. Z.; Ennaoui, A.; Dittrich, Th.; Lux-Steiner, M.

    2013-06-01

    Lattice positions of Sn in kesterite Cu2ZnSnS4 and Cu2SnS3 nanoparticles and thin films were investigated by XANES (x-ray absorption near edge structure) analysis at the S K-edge. XANES spectra were analyzed by comparison with simulations taking into account anti-site defects and vacancies. Annealing of Cu2ZnSnS4 nanoparticle thin films led to a decrease of Sn at its native and defect sites. The results show that XANES analysis at the S K-edge is a sensitive tool for the investigation of defect sites, being critical in kesterite thin film solar cells.

  3. Studies of Nuclei Close to 132Sn Using Single-Neutron Transfer Reactions

    International Nuclear Information System (INIS)

    Jones, K.L.; Pain, S.D.; Kozub, R.L.; Adekola, Aderemi S.; Bardayan, Daniel W.; Blackmon, Jeff C.; Catford, Wilton N.; Chae, K.Y.; Chipps, K.; Cizewski, J.A.; Erikson, Luke; Gaddis, A.L.; Greife, U.; Grzywacz, R.K.; Harlin, Christopher W.; Hatarik, Robert; Howard, Joshua A.; James, J.; Kapler, R.; Krolas, W.; Liang, J. Felix; Ma, Zhanwen; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D.; O'Malley, Patrick; Patterson, N.P.; Paulauskas, Stanley; Shapira, Dan; Shriner, J.F. Jr.; Sikora, M.; Sissom, D.J.; Smith, Michael Scott; Swan, T.P.; Thomas, J.S.; Wilson, Gemma L.

    2009-01-01

    Neutron transfer reactions were performed in inverse kinematics using radioactive ion beams of 132Sn, 130Sn, and 134Te and deuterated polyethylene targets. Preliminary results are presented. The Q-value spectra for 133Sn, 131Sn and 135Te reveal a number of previously unobserved peaks. The angular distributions are compatible with the expected lf7/2 nature of the ground state of 133Sn, and 2p3/2 for the 3.4 MeV state in 131Sn.

  4. Thin films of preparation SnOx by evaporation and pulverization reactive in vapor phase

    International Nuclear Information System (INIS)

    Solis, J.; Estrada, W.; Soares, M.; Schreiner, W.

    1993-01-01

    In this work we obtained SnO x thin films by reactive evaporation. The structure and composition of the films were characterized by x-ray diffraction and Moessbauer spectroscopy. The samples as deposited present different kind of microstructures depending on the parameters deposition, such as substrate temperature and oxygen pressure. In general the samples present three pushes: Sn, SnO and SnO 2 . When the samples are subjected to heat treatment, the as deposited SnO x finally converts to SnO 2 . (authors) 10 refs., 4 figs

  5. Production of Sn/SnO2/MWCNT composites by plasma oxidation after thermal evaporation from pure Sn targets onto buckypapers.

    Science.gov (United States)

    Alaf, M; Gultekin, D; Akbulut, H

    2012-12-01

    In this study, tin/tinoxide/multi oxide/multi walled carbon nano tube (Sn/SnO2/MWCNT) composites were produced by thermal evaporation and then subsequent plasma oxidation. Buckypapers having controlled porosity were prepared by vacuum filtration from functionalized MWCNTs. Pure metallic tin was thermally evaporated on the buckypapers in argon atmosphere with different thicknesses. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypaper to form a nanocomposite. The tin/MWCNT composites were subjected to plasma oxidation process at oxygen/argon gas mixture. Three different plasma oxidation times (30, 45 and 60 minutes) were used to investigate oxidation and physical and microstructural properties. The effect of coating thickness and oxidation time was investigated to understand the effect of process parameters on the Sn and SnO2 phases after plasma oxidation. Quantitative phase analysis was performed in order to determine the relative phase amounts. The structural properties were studied by field-emission gun scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD).

  6. The recruitment of the U5 snRNP to nascent transcripts requires internal loop 1 of U5 snRNA.

    Science.gov (United States)

    Kim, Rebecca; Paschedag, Joshua; Novikova, Natalya; Bellini, Michel

    2012-12-01

    In this study, we take advantage of the high spatial resolution offered by the nucleus and lampbrush chromosomes of the amphibian oocyte to investigate the mechanisms that regulate the intranuclear trafficking of the U5 snRNP and its recruitment to nascent transcripts. We monitor the fate of newly assembled fluorescent U5 snRNP in Xenopus oocytes depleted of U4 and/or U6 snRNAs and demonstrate that the U4/U6.U5 tri-snRNP is not required for the association of U5 snRNP with Cajal bodies, splicing speckles, and nascent transcripts. In addition, using a mutational analysis, we show that a non-functional U5 snRNP can associate with nascent transcripts, and we further characterize internal loop structure 1 of U5 snRNA as a critical element for licensing U5 snRNP to target both nascent transcripts and splicing speckles. Collectively, our data support the model where the recruitment of snRNPs onto pre-mRNAs is independent of spliceosome assembly and suggest that U5 snRNP may promote the association of the U4/U6.U5 tri-snRNP with nascent transcripts.

  7. First Principles Investigation of the Mechanical, Thermodynamic and Electronic Properties of FeSn{sub 5} and CoSn{sub 5} Intermetallic Phases under Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenming; Liu, Jing; Wang, Hong [China Building Materials Academy, Beijing (China); Zhang, Zhenwei [Linyi Academy of Technology Cooperation and Application, Linyi (China); Zhang, Liang [NeoTrident Technology Ltd., Shanghai (China); Bu, Yuxiang [Shandong University, Jinan (China)

    2017-02-15

    For guidance for developing Fe/Co-Sn-based anode materials for lithium-ion batteries, the mechanical, thermodynamic and electronic properties of FeSn{sub 5} and CoSn{sub 5} intermetallic phases under pressures ranging from 0 to 30 GPa have been investigated systematically using first-principles total-energy calculations within the framework of the generalized gradient approximation. The pressure was found to have significant effects on the mechanical, thermodynamic and electronic properties of these compounds. In the selected pressure range, CoSn{sub 5} has a more negative formation enthalpy than FeSn{sub 5}. Based on the calculated elastic constants, the bulk modulus, shear modulus, and Young's modulus were determined via the Viogt-Reuss-Hill averaging scheme. The variations of specific heats at constant volume for FeSn{sub 5} and CoSn{sub 5} in a wide pressure (0 - 30 GPa) and temperature (0 - 1000 K) range are also predicted from phonon density of states calculation. The calculated results suggested that both FeSn{sub 5} and CoSn{sub 5} are mechanically stable at pressure from 0 to 30 GPa. FeSn{sub 5} is dynamically stable at pressure up to, 30 GPa, at least, however, CoSn{sub 5} is dynamically stable no higher than 15 GPa.

  8. Ethanol electrooxidation on novel carbon supported Pt/SnOx/C catalysts with varied Pt:Sn ratio

    International Nuclear Information System (INIS)

    Jiang, L.; Colmenares, L.; Jusys, Z.; Sun, G.Q.; Behm, R.J.

    2007-01-01

    Novel carbon supported Pt/SnO x /C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO ad stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO x /C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO x /C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO x /C catalysts, acetic acid and acetaldehyde represent dominant products, CO 2 formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol -1 ), but are lower than on Pt/C (32 kJ mol -1 ). The somewhat better performance of the Pt/SnO x /C catalysts compared to alloyed PtSn x /C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies

  9. Stress effects on multifilamentary Nb3Sn wire

    International Nuclear Information System (INIS)

    Bartlett, R.J.; Taylor, R.D.; Thompson, J.D.

    1979-01-01

    Critical current I/sub c/ measurements were obtained on highly stabilized mf Nb 3 Sn wires as a function of heat treatment, stress, temperature, and applied magnetic field. The ratio of the area of the copper to bronze core-niobium tube is about 8, and the filaments are concentrated in the inner 30% of the wire cross section. Values of I/sub c/ and T/sub c/ were determined for samples subjected to a wide range of heat treatments. Diffusion reaction times and temperatures in the ranges 16 to 128 hr and 700 to 750 0 C provided a number of mf Nb 3 Sn wires having similar I/sub c/ characteristics. To some extent the residual compressive loading on the Nb 3 Sn wires varied with the particular heat treatment. This loading arises primarily from the differential contraction of the remaining bronze and the Nb 3 Sn layer when cooled from the reaction temperature to the operating temperature. It was found that, by controlled bending or stretching of the wires, whereby some of the strain in the Nb 3 Sn is relieved, the I/sub c/ at 14 K is increased by as much as 30% and the critical temperature is increased by up to 1 K

  10. Structural and transport properties of Sn-Mg alloys

    International Nuclear Information System (INIS)

    Meydaneri, F.; Saatci, E.; Oezdemir, M.; Ari, M.; Durmus, S.

    2010-01-01

    The structural and temperature dependence transport of Sn-Mg alloys have been investigated for five different samples (Pure Sn, Sn-1.0 wt % Mg , Sn-2.0 wt % Mg , Sn-6.0 wt.% Mg and Pure Mg). Scanning Electron Microscopy (SEM), x-ray diffraction (XRD) and Energy Dispersive x-ray Analysis (EDX) measurements were carried out in order to clarify the structural properties of the samples. It has been found that, the samples have tetragonal crystal symmetry except the pure Mg which has hexagonal crystal symmetry. The cell parameters decrease slightly with addition of Mg element. The SEM micrographs of the samples show that, the samples have smooth surfaces with clear grain boundary. There is no crack, porosity or defects on the surfaces. The electrical resistivity of the samples increases almost linearly with the increasing temperature, which were measured by four-point probe technique. The thermal conductivity values are in between 0.60-1.00 W/Km, which are decrease slightly with temperature and increase with composition of Mg. The thermal conductivity values of the alloys are in between the values of the pure samples. Thermal conductivity results of the alloys have been compared with available other studies and a good agreement has been seen between the results. In addition, the temperature coefficients of electrical resistivity and thermal conductivity have been determined, which are independent with the compositions of alloying elements

  11. Field emission from patterned SnO2 nanostructures

    International Nuclear Information System (INIS)

    Zhang Yongsheng; Yu Ke; Li Guodong; Peng Deyan; Zhang Qiuxiang; Hu Hongmei; Xu Feng; Bai Wei; Ouyang Shixi; Zhu Ziqiang

    2006-01-01

    A simple and reliable method has been developed for synthesizing finely patterned tin dioxide (SnO 2 ) nanostructure arrays on silicon substrates. A patterned Au catalyst film was prepared on the silicon wafer by radio frequency (RF) magnetron sputtering and photolithographic patterning processes. The patterned SnO 2 nanostructures arrays, a unit area is of ∼500 μm x 200 μm, were synthesized via vapor phase transport method. The surface morphology and composition of the as-synthesized SnO 2 nanostructures were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanism of formation of SnO 2 nanostructures was also discussed. The measurement of field emission (FE) revealed that the as-synthesized SnO 2 nanorods, nanowires and nanoparticles arrays have a lower turn-on field of 2.6, 3.2 and 3.9 V/μm, respectively, at the current density of 0.1 μA/cm 2 . This approach must have a wide variety of applications such as fabrications of micro-optical components and micropatterned oxide thin films used in FE-based flat panel displays, sensor arrays and so on

  12. Laser Spectroscopy Studies in the Neutron-Rich Sn Region

    CERN Multimedia

    Obert, J

    2002-01-01

    We propose to use the powerful laser spectroscopy method to determine the magnetic moment $\\mu$ and the variation of the mean square charge radius ($\\delta\\,\\langle$r$_{c}^{2}\\,\\rangle$) for ground and long-lived isomeric states of the Sn isotopes from A=125 to the doubly-magic $^{132}$Sn isotope and beyond. For these neutron-rich Sn nuclei, numerous $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ curves have already been calculated and the predictions depend upon the effective interactions used. Therefore, a study of the effect of the shell closure N=82 on the $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ values in the Z=50 magic nuclei is of great interest, especially because $^{132}$Sn is located far from the stability valley. It will help to improve the parameters of the effective interactions and make them more suitable to predict the properties of exotic nuclei. \\\\ \\\\The neutron-rich Sn isotopes produced with an uranium carbide target, are ionized using either a hot plasma ion source or the resonant ionization laser ion ...

  13. Experimental study of the Ag-Sn-In phase diagram

    International Nuclear Information System (INIS)

    Vassilev, Gueorgui P.; Dobrev, Evgueni S.; Tedenac, Jean-Claude

    2005-01-01

    Combined metallographic, differential scanning calorimetry, X-ray and scanning electron microscopy studies have been performed using 27 ternary alloys. The microhardness of the α(Ag), ε(Ag 3 Sn) and ζ(Ag 4 Sn,Ag 3 In) phases has been measured. The ternary extension of the phase φ(Ag x In y Sn z , where x ∼ 0.36, y ∼ 0.61, z ∼ 0.03) has been revealed in some specimens, although the binary compound (AgIn 2 ) melts at 166 deg. C. This finding is attributed to the limited cooling rate. The solubility ranges of the solid solution and the intermetallic phases have been determined. The tin and the indium show approximately equal mutual solubility (around 2 at.%) in the ternary extensions of their Ag-Sn or Ag-In phases. The experimental data have been compared with a calculated isothermal section at 280 deg. C and with a vertical section at 2.5 at.% Ag. The thermal analyses have confirmed, in general, the temperatures of the invariant reactions in the Ag-Sn-In system as calculated by literature data

  14. Liver scintigraphy with sup(99m)Tc-Sn-colloid

    International Nuclear Information System (INIS)

    Suzuki, Masaaki

    1976-01-01

    Basic and clinical studies of sup(99m)Tc-Sn-colloid (Tc-Sn-C) were made on liver scintigraphy for comparison with 198 Au-colloid in blood clearance, liver accumulation, and spleen imaging strength. Tc-Sn-C was excellent in ease of sterilization, simplicity of preparation, reduction in the exposure dose for the examiner, labeling rate, and stability, and it was effective as a drug for liver scintigraphy. The blood clearance T1/2 can be an indicator for the blood flow rate in the liver, similarly to the Au-C method. Although a decrease in the liver radioactivity after liver accumulation was observed, it was not thought to affect liver scintigraphy. A clear shadow of the liver was obtained in all cases, and there seemed to be no differences between the commercially prepared Tc-Sn-C and the Tc-Sn-C which must be prepared each time. The spleen imaging strength was thought to be effective as a supplementary diagnosis for splenic diseases. No allergic symptoms appeared immediately after examination. (Chiba, N.)

  15. Nuclear structure near the doubly-magic 100Sn

    International Nuclear Information System (INIS)

    Grawe, H.; Hu, Z.; Roeckl, E.; Gorska, M.; Nyberg, J.; Gadea, A.; Angelis, G. de

    1998-09-01

    The single particle (hole) energies in 100 Sn, as extrapolated by a shell model analysis of the neighbouring nuclei, show a remarkable similarity to those in 36 Ni, one major shell lower. This is borne out in nearly identical I π =2 + excitation energies, implying E(2 + )≅3 MeV in 100 Sn, and a large neutron effective E2 charge ε≥1.6ε. In contrast a small proton polarisation charge δε≤0.3ε is found, pointing to a large isovector charge. Mean field predictions for single particle energies show substantial deviations from the experimental extrapolation. From the experimental two-proton hole spectrum in 98 Cd an improved empirical interaction is extracted for the π(p 1/2 ,g 9/2 ) model space yielding a good description of the N=50 isotones 95 Rh to 98 Cd. In 104 Sn, for the first time in this region, strong E3 transitions with B(E3)≥17 W.u. were identified, indicating E(3 - )≅3 MeV in 100 Sn. New experimental devices, as the Ge-cluster cube and total absorption spectrometers, applied in a pioneering experiment to the β + /EC decay of 97 Ag, have led to a consistent picture of the Gamow-Teller quenching around 100 Sn. The experimental results are discussed in the framework of various shell model approaches by using both empirical and realistic interactions. (orig.)

  16. Superhydrophilic SnO{sub 2} nanosheet-assembled film

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yoshitake, E-mail: masuda-y@aist.go.jp; Kato, Kazumi

    2013-10-01

    SnO{sub 2} films were fabricated on fluorine-doped tin oxide (FTO) substrates in aqueous solutions. The films of about 800 nm in thickness grew in the solutions containing SnF{sub 2} of 25 mM at 90 °C for 24 h. They consisted of nanosheets of about 5–10 nm in thickness and about 100–1600 nm in plane size. The films had gradient structure of nanosheets. Smaller nanosheets formed dense structures in a bottom area, while larger nanosheets formed porous structures in a surface area of the films. The SnO{sub 2} films showed higher transparency than bare FTO substrates in a visible light region of 470 to 850 nm. Decrease of reflectance increased transparency. The SnO{sub 2} films had superhydrophilic surfaces of static contact angle below 1°. Nanosheet-assembled structures contributed high hydrophilicity. The surfaces were further modified with light irradiation. High speed camera observation showed that spread speed of water was improved with the irradiation. Removal of surface adsorbed organic molecules and increase in the number of hydroxyl groups brought superhydrophilicity and high spread speed. - Highlights: ► SnO{sub 2} nanosheet films were prepared from aqueous solutions. ► The antireflective films showed superhydrophilicity. ► Crystal growth mechanism of the gradient structures is discussed.

  17. Hydrogen peroxide route to Sn-doped titania photocatalysts

    Directory of Open Access Journals (Sweden)

    Štengl Václav

    2012-10-01

    Full Text Available Abstract Background The work aims at improving photocatalytic activity of titania under Vis light irradiation using modification by Sn ions and an original, simple synthesis method. Tin-doped titania catalysts were prepared by thermal hydrolysis of aqueous solutions of titanium peroxo-complexes in the presence of SnCl4 or SnCl2 using an original, proprietary "one pot" synthesis not employing organic solvents, metallo-organic precursors, autoclave aging nor post-synthesis calcination. The products were characterized in details by powder diffraction, XPS, UV–vis, IR, and Raman spectroscopies, electron microscopy and surface area and porosity measurements Results The presence of tin in synthesis mixtures favors the formation of rutile and brookite at the expense of anatase, decreases the particle size of all formed titania polymorphs, and extends light absorption of titania to visible light region >400 nm by both red shift of the absorption edge and introduction of new chromophores. The photocatalytic activity of titania under UV irradiation and >400 nm light was tested by decomposition kinetics of Orange II dye in aqueous solution Conclusions Doping by Sn improves titania photoactivity under UV light and affords considerable photoactivity under >400 nm light due to increased specific surface area and a phase heterogeneity of the Sn-doped titania powders.

  18. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  19. The crystallisation of Cu2ZnSnS4 thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

    International Nuclear Information System (INIS)

    Schurr, R.; Hoelzing, A.; Jost, S.; Hock, R.; Voss, T.; Schulze, J.; Kirbs, A.; Ennaoui, A.; Lux-Steiner, M.; Weber, A.; Koetschau, I.; Schock, H.-W.

    2009-01-01

    The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu 2 ZnSnS 4 based thin film solar cells. A kesterite based solar cell (size 0.5 cm 2 ) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu-Zn-Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu 2 SnS 3 and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu 3 Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu 6 Sn 5 and Sn phases were detected. The formation mechanism of Cu 2 SnS 3 involves the binary sulphides Cu 2-x S and SnS 2 in the absence of the binary precursor phase Cu 6 Sn 5 . The presence of Cu 6 Sn 5 leads to a preferred formation of Cu 2 SnS 3 via the reaction educts Cu 2-x S and SnS 2 in the presence of a SnS 2 (Cu 4 SnS 6 ) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase

  20. Dominant effect of high anisotropy in β-Sn grain on electromigration-induced failure mechanism in Sn-3.0Ag-0.5Cu interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Huang, M.L., E-mail: huang@dlut.edu.cn; Zhao, J.F.; Zhang, Z.J.; Zhao, N.

    2016-09-05

    The effect of high diffusivity anisotropy in β-Sn grain on electromigration behavior of micro-bumps was clearly demonstrated using Sn-3.0Ag-0.5Cu solder interconnects with only two β-Sn grains. The orientation of β-Sn grain (θ is defined as the angle between the c-axis of β-Sn grain and the electron flow direction) is becoming the most crucial factor to dominate the different electromigration-induced failure modes: 1) the excessive dissolution of the cathode Cu, blocking at the grain boundary and massive precipitation of columnar Cu{sub 6}Sn{sub 5} intermetallic compounds (IMCs) in the small angle θ β-Sn grain occur when electrons flow from a small angle θ β-Sn grain to a large one; 2) void formation and propagation occur at the cathode IMC/solder interface and no Cu{sub 6}Sn{sub 5} IMCs precipitate within the large angle θ β-Sn grain when electrons flow in the opposite direction. The EM-induced failure mechanism of the two β-Sn grain solder interconnects is well explained in viewpoint of atomic diffusion flux in β-Sn. - Highlights: • High anisotropy in β-Sn dominates different electromigration-induced failure mode. • Excessive dissolution of cathode Cu occurs if electrons flow in forward direction. • Voids initiate and propagate at cathode if electrons flow in reverse direction. • Failure modes are well explained in viewpoint of atomic diffusion flux in β-Sn.

  1. Kinetics of plasma oxidation of germanium-tin (GeSn)

    Science.gov (United States)

    Wang, Wei; Lei, Dian; Dong, Yuan; Zhang, Zheng; Pan, Jisheng; Gong, Xiao; Tok, Eng-Soon; Yeo, Yee-Chia

    2017-12-01

    The kinetics of plasma oxidation of GeSn at low temperature is investigated. The oxidation process is described by a power-law model where the oxidation rate decreases rapidly from the initial oxidation rate with increasing time. The oxidation rate of GeSn is higher than that of pure Ge, which can be explained by the higher chemical reaction rate at the GeSn-oxide/GeSn interface. In addition, the Sn atoms at the interface region exchange positions with the underlying Ge atoms during oxidation, leading to a SnO2-rich oxide near the interface. The bandgap of GeSn oxide is extracted to be 5.1 ± 0.2 eV by XPS, and the valence band offset at the GeSn-oxide/GeSn heterojunction is found to be 3.7 ± 0.2 eV. Controlled annealing experiments demonstrate that the GeSn oxide is stable with respect to annealing temperatures up to 400 °C. However, after annealing at 450 °C, the GeO2 is converted to GeO, and desorbs from the GeSn-oxide/GeSn, leaving behind Sn oxide.

  2. Controlling Cu–Sn mixing so as to enable higher critical current densities in RRP® Nb3Sn wires

    Science.gov (United States)

    Sanabria, Charlie; Field, Michael; Lee, Peter J.; Miao, Hanping; Parrell, Jeff; Larbalestier, David C.

    2018-06-01

    Dipole magnets for the proposed Future Circular Collider (FCC) demand specifications significantly beyond the limits of all existing Nb3Sn wires, in particular a critical current density (J c) of more than 1500 A mm‑2 at 16 T and 4.2 K with an effective filament diameter (D eff) of less than 20 μm. The restacked-rod-process (RRP®) is the technology closest to meeting these demands, with a J c (16 T) of up to 1400 A mm‑2, residual resistivity ratio > 100, for a sub-element size D s of 58 μm (which in RRP® wires is essentially the same as D eff). An important present limitation of RRP® is that reducing the sub-element size degrades J c to as low as 900 A mm‑2 at 16 T for D s = 35 μm. To gain an understanding of the sources of this J c degradation, we have made a detailed study of the phase evolution during the Cu–Sn ‘mixing’ stages of the wire heat treatment that occur prior to Nb3Sn formation. Using extensive microstructural quantification, we have identified the critical role that the Sn–Nb–Cu ternary phase (Nausite) can play. The Nausite forms as a well-defined ring between the Sn source and the Cu/Nb filament pack, and acts as an osmotic membrane in the 300 °C–400 °C range—greatly inhibiting Sn diffusion into the Cu/Nb filament pack while supporting a strong Cu counter-diffusion from the filament pack into the Sn core. This converts the Sn core into a mixture of the low melting point (408 °C) η phase (Cu6Sn5) and the more desirable ε phase (Cu3Sn), which decomposes at 676 °C. After the mixing stages, when heated above 408 °C towards the Nb3Sn reaction, any residual η liquefies to form additional irregular Nausite on the inside of the membrane. All Nausite decomposes into NbSn2 on further heating, and ultimately transforms into coarse-grain (and often disconnected) Nb3Sn which has little contribution to current transport. Understanding this critical Nausite reaction pathway has allowed us to simplify the mixing heat treatment to

  3. Thermoelectric Materials

    Science.gov (United States)

    Gao, Peng; Berkun, Isil; Schmidt, Robert D.; Luzenski, Matthew F.; Lu, Xu; Bordon Sarac, Patricia; Case, Eldon D.; Hogan, Timothy P.

    2014-06-01

    Mg2(Si,Sn) compounds are promising candidate low-cost, lightweight, nontoxic thermoelectric materials made from abundant elements and are suited for power generation applications in the intermediate temperature range of 600 K to 800 K. Knowledge on the transport and mechanical properties of Mg2(Si,Sn) compounds is essential to the design of Mg2(Si,Sn)-based thermoelectric devices. In this work, such materials were synthesized using the molten-salt sealing method and were powder processed, followed by pulsed electric sintering densification. A set of Mg2.08Si0.4- x Sn0.6Sb x (0 ≤ x ≤ 0.072) compounds were investigated, and a peak ZT of 1.50 was obtained at 716 K in Mg2.08Si0.364Sn0.6Sb0.036. The high ZT is attributed to a high electrical conductivity in these samples, possibly caused by a magnesium deficiency in the final product. The mechanical response of the material to stresses is a function of the elastic moduli. The temperature-dependent Young's modulus, shear modulus, bulk modulus, Poisson's ratio, acoustic wave speeds, and acoustic Debye temperature of the undoped Mg2(Si,Sn) compounds were measured using resonant ultrasound spectroscopy from 295 K to 603 K. In addition, the hardness and fracture toughness were measured at room temperature.

  4. Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A

    International Nuclear Information System (INIS)

    McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Chornock, Ryan; Holtzman, Jon A.; Balam, David D.; Branch, David; Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong; Frieman, Joshua; Fynbo, Johan; Leloudas, Giorgos; Galbany, Lluis; Garnavich, Peter M.; Graham, Melissa L.; Hsiao, Eric Y.; Leonard, Douglas C.

    2014-01-01

    We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are observed in other SNe at late phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I more than a year past maximum light, along with narrow [Fe II] and [Ca II] emission. We use spectral features to constrain the temperature and density of the ejecta, and find high densities at late times, with n e ≳ 10 9 cm –3 . Such high densities should yield enhanced cooling of the ejecta, making these objects good candidates to observe the expected 'infrared catastrophe', a generic feature of SN Ia models. However, our HST photometry of SN 2008A does not match the predictions of an infrared catastrophe. Moreover, our HST observations rule out a 'complete deflagration' that fully disrupts the white dwarf for these peculiar SNe, showing no evidence for unburned material at late times. Deflagration explosion models that leave behind a bound remnant can match some of the observed properties of SNe Iax, but no published model is consistent with all of our observations of SNe 2005hk and 2008A.

  5. Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A

    Energy Technology Data Exchange (ETDEWEB)

    McCully, Curtis; Jha, Saurabh W. [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Foley, Ryan J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Chornock, Ryan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Holtzman, Jon A. [Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States); Balam, David D. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Branch, David [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Frieman, Joshua [Kavli Institute for Cosmological Physics and Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Fynbo, Johan; Leloudas, Giorgos [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Galbany, Lluis [Institut de Física d' Altes Energies, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Garnavich, Peter M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Graham, Melissa L. [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Leonard, Douglas C., E-mail: cmccully@physics.rutgers.edu [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); and others

    2014-05-10

    We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are observed in other SNe at late phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I more than a year past maximum light, along with narrow [Fe II] and [Ca II] emission. We use spectral features to constrain the temperature and density of the ejecta, and find high densities at late times, with n{sub e} ≳ 10{sup 9} cm{sup –3}. Such high densities should yield enhanced cooling of the ejecta, making these objects good candidates to observe the expected 'infrared catastrophe', a generic feature of SN Ia models. However, our HST photometry of SN 2008A does not match the predictions of an infrared catastrophe. Moreover, our HST observations rule out a 'complete deflagration' that fully disrupts the white dwarf for these peculiar SNe, showing no evidence for unburned material at late times. Deflagration explosion models that leave behind a bound remnant can match some of the observed properties of SNe Iax, but no published model is consistent with all of our observations of SNe 2005hk and 2008A.

  6. Influences of the quantity of Mg2Sn phase on the corrosion behavior of Mg-7Sn magnesium alloy

    International Nuclear Information System (INIS)

    Liu Xianbin; Shan Dayong; Song Yingwei; Chen Rongshi; Han Enhou

    2011-01-01

    The influence of the quantity of the Mg 2 Sn phase on the corrosion behavior of different solution temperature treated Mg-7Sn magnesium alloy has been investigated by electrochemical measurements, scanning electron microscope (SEM) observation, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. With the increase of solution temperature, the quantity of Mg 2 Sn phase decreased and the tin concentration of matrix increased. The dissolved tin in Mg matrix took part in the film formation and the constituent of film was magnesium oxide and stannic oxide. The corrosion mode and corrosion rate were associated with the quantity of Mg 2 Sn phases and tin concentration of the matrix. If most of tin was present as Mg 2 Sn, the corrosion mode was pitting corrosion and it accelerated the corrosion rate. If most of tin was dissolved in matrix, the corrosion mode was filiform corrosion and it decreased the corrosion rate. The experiment evidences demonstrated that the corrosion resistance can be improved by increasing the tin concentration of matrix and the lowest corrosion rate was observed for sample solution treated at 540 o C.

  7. CEF-scheme of a semimetal Ce3Sn7

    International Nuclear Information System (INIS)

    Okuda, Yusuke; Yamamoto, Takeshi; Honda, Daisuke; Shishido, Hiroaki; Galatanu, Andrei; Haga, Yoshinori; Matsuda, Tatsuma D.; Takeuchi, Tetsuya; Kindo, Koichi; Sugiyama, Kiyohiro; Settai, Rikio; O-bar nuki, Yoshichika

    2005-01-01

    We measured the magnetic susceptibility and magnetization of an antiferromagnet Ce 3 Sn 7 with the orthorhombic crystal structure. The experimental data are found to be well explained on the basis of the crystalline electric field (CEF) 4f-scheme under the assumption that two Ce atoms in the 2(a) site possess a magnetic moment of 0.36μ B /Ce and one Ce atom in the 4(i) site possesses no magnetic moment as in a valence fluctuating compound CeSn 3 , which was previously proposed by Bonnet et al. Furthermore, we carried out the de Haas-van Alphen experiment. The detected Fermi surfaces are many in number but are extremely small in volume, indicating that Ce 3 Sn 7 is a semimetal

  8. Adsorption pertechnetate ions on the substituted Sn-hydroxyapatite

    International Nuclear Information System (INIS)

    Hamarova, A.; Rosskopfova, O.; Pivarciova, L.

    2015-01-01

    Hydroxyapatite is suitable adsorbent for heavy metals and radionuclides due to its large surface area, high stability under redox conditions. SnCl 2 for its reducing properties is used in biomedical applications and industrial technologies, for its reducing properties. The adsorption of TcO 4 - to the HA samples, prepared by wet precipitation method, was studied by the d radio-indication method. Radionuclide 99m Tc was used as radioisotope indicator. The effect of contact time on the adsorption of 99m TcO 4 - ions on the Sn-HA was studied. Sn 2+ ions reduced Tc (VII) to Tc (IV) forming TcO 2 , TcO(OH) 2 or more precisely TcO 2 ·2H 2 O, which can be adsorbed on the surface of the HA, or to form complexes on the surface of the hydroxyapatite. (authors)

  9. Quasi-two-dimensional thermoelectricity in SnSe

    Science.gov (United States)

    Tayari, V.; Senkovskiy, B. V.; Rybkovskiy, D.; Ehlen, N.; Fedorov, A.; Chen, C.-Y.; Avila, J.; Asensio, M.; Perucchi, A.; di Pietro, P.; Yashina, L.; Fakih, I.; Hemsworth, N.; Petrescu, M.; Gervais, G.; Grüneis, A.; Szkopek, T.

    2018-01-01

    Stannous selenide is a layered semiconductor that is a polar analog of black phosphorus and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle-resolved photoemission spectroscopy, optical reflection spectroscopy, and magnetotransport measurements reveal a multiple-valley valence-band structure and a quasi-two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250 cm2/V s at T =1.3 K . SnSe is thus found to be a high-quality quasi-two-dimensional semiconductor ideal for thermoelectric applications.

  10. Phase diagram Fe-Sn-Sr. New experimental results

    International Nuclear Information System (INIS)

    Nieva, N; Jimenez, M.J; Gomez, A; Corvalan Moya, C; Arias, D

    2012-01-01

    Zr-based alloys are widely used in nuclear industry due to their specific characteristics. The information of the phase diagrams of the ternary system Fe-Zr-Sn is scarce. In this work we investigate, in a experimental way, the central and the Fe-Sn binary adjacent regions of the Fe-Sn-Zr Gibbs triangle at the temperature of 800 o C. For the experimental work, a set of seven ternary alloys was designed, produced and examined by different complementary techniques. There were performed two types of heat treatments: one of medium and another of long duration. We present a new proposal for the 800 o C isothermal section. The boundaries of the identified phases and the fields of one, two and three phases are indicated in the diagram

  11. Gas Sensing Properties of Ordered Mesoporous SnO2

    Directory of Open Access Journals (Sweden)

    Michael Tiemann

    2006-04-01

    Full Text Available We report on the synthesis and CO gas-sensing properties of mesoporoustin(IV oxides (SnO2. For the synthesis cetyltrimethylammonium bromide (CTABr wasused as a structure-directing agent; the resulting SnO2 powders were applied as films tocommercially available sensor substrates by drop coating. Nitrogen physisorption showsspecific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verifiedby TEM. The film conductance was measured in dependence on the CO concentration inhumid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivityat low CO concentrations and turn out to be largely insensitive towards changes in therelative humidity. We compare the materials with commercially available SnO2-basedsensors.

  12. Some kinetic properties of DySnSe2 combination

    International Nuclear Information System (INIS)

    Murguzov, M.I.; Mammadova, E.R.

    2008-01-01

    Recently, to the acquisition of multi-component alloys and combination in the presence of rare-earth metals (REM) interest has grown considerably. According to preliminary data, in the presence of rare-earth metals you can obtain perspective semiconductor materials which are of practical importance, and can be used in various fields of microelectronics in a complex system of chalcogenides. DySnSe 2 combination is also includes to this system. Physical peculiarities of these combinations have been studied in wide interval. DySnSe 2 combination crystallizes in ortho rhombic crystal system and is an indemnification n-type semiconductor material. The mechanism of electrical conductivity in DySnSe 2 semiconductor combination is complicated and cargo carrier scattering changes at low temperatures. That is why, the mixed type conductivity occurs

  13. Ultraviolet photodetectors made from SnO2 nanowires

    International Nuclear Information System (INIS)

    Wu, Jyh-Ming; Kuo, Cheng-Hsiang

    2009-01-01

    SnO 2 nanowires can be synthesized on alumina substrates and formed into an ultraviolet (UV) photodetector. The photoelectric current of the SnO 2 nanowires exhibited a rapid photo-response as a UV lamp was switched on and off. The ratio of UV-exposed current to dark current has been investigated. The SnO 2 nanowires were synthesized by a vapor-liquid-solid process at a temperature of 900 o C. It was found that the nanowires were around 70-100 nm in diameter and several hundred microns in length. High-resolution transmission electron microscopy (HRTEM) image indicated that the nanowires grew along the [200] axis as a single crystallinity. Cathodoluminescence (CL), thin-film X-ray diffractometry, and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized nanowires.

  14. Development of Nb3Sn AC superconducting wire. Pt. 2

    International Nuclear Information System (INIS)

    Kasahara, Hobun; Torii, Shinji; Akita, Shirabe; Ueda, Kiyotaka; Kubota, Yoji; Yasohama, Kazuhiko; Kobayashi, Hisayasu; Ogasawara, Takeshi.

    1993-01-01

    For the realization of superconducting power apparatus, it is important that the development of highly stable superconducting cables. Nb 3 Sn wire has higher critical temperature than NbTi wire. Therefore, it is possible to make highly stable superconducting wires. In this report, we examine a manufacturing process of Ac Nb 3 Sn wire. This manufacturing process has four times higher critical current density than conventional processes. We have made a 400 kVA class AC coil with React and Wind method. The loss density of this coil was 20MW/m 3 at just before the quench. In this case, the temperature of cable increased about 3.8 K. This means that the Nb 3 Sn coil has a very high stability. (author)

  15. Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys; Efeitos da adicao de Sn na evolucao microestrutural e em propriedades mecanicas de ligas Ti-Nb-Sn biomedicas fundidas por centrifugacao

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, E.S.N.; Contieri, R.J.; Caram, R., E-mail: ederlopes@fem.unicamp.b [Universidade Estadual de Campinas (DEMA/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais; Moraes, P.E.L. [FATEC Artur Azevedo, Mogi Mirim, SP (Brazil); Costa, A.M.S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materiais

    2010-07-01

    The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

  16. Old friends in a new light: 'SnSb' revisited

    International Nuclear Information System (INIS)

    Noren, Lasse; Withers, Ray L.; Schmid, Siegbert; Brink, Frank J.; Ting, Valeska

    2006-01-01

    The binary pnictide 'SnSb' has been re-investigated using a combination of X-ray, synchrotron and electron diffraction as well as electron microprobe analysis. Its structure was found to be incommensurately modulated with an underlying rhombohedral parent structure of space group symmetry R3-bar m (No. 166), unit cell parameters a h =b h =4.3251(4)A, c h =5.3376(6)A in the hexagonal setting. The incommensurate primary modulation wave vector q h =1.3109(9)c h * and the superspace group symmetry is R3-bar m (0, 0, ∼1.311) (No. 166.1). The refinement of the incommensurate structure indicates that the satellite reflections arise from displacive shifts of presumably essentially pure Sn and Sb layers along the hexagonal c-axis, with increasing distance between the Sn-layers and decreasing distance between the Sb layers

  17. Studies on Nb3Sn field coils for superconducting machine

    International Nuclear Information System (INIS)

    Fujino, H.; Nose, S.

    1981-01-01

    This paper describes experimental studies on several coils wound with multifilamentary (MF) Nb 3 Sn cables with reinforcing strip for superconducting rotating machine application. To use a Nb 3 Sn superconductor to field winding of a rotating machine, several coil performances of pre-reacted, bronze processed and stranded MF Nb 3 Sn cables were investigated, mainly in relation to stress effect. Bending strain up to 0.64% in strand and winding stress of 5 kg/mm 2 have resulted in nondegradation in coil performance. A pair of impregnated race-track coils designed for a 30 MVA synchronous condenser was energized successfully up to 80% of critical current without quench. 8 refs

  18. Assay Validation For Quantitation of Sn 2+ In Radiopharmaceutical Kits

    International Nuclear Information System (INIS)

    Muthalib, A; Ramli, Martalena; Herlina; Sarmini, Endang; Suharmadi; Besari, Canti

    1998-01-01

    An assay validation for quantitation of Sn2+ in radiopharmaceutical kits based on indirect iodometric titration is described. The method is based on the oxidation of sn2+ using a known excess of iodine and the excess unreacted iodine titrated with thiosulphate. Typical analytical parameters considered in this assay validation are precision, accuracy, selectivity or specificity, range, and linearity. The precision of the analytical method is quit good represented by coefficient of variance in range of 1.0% to 6.9 %, for 10 runs of analysis except one analysis shows the coefficient of 10.2 %. The method has an accuracy of 95.6 % - 99 % as percent recoveries at theoretical Sn2+ amounts of 463 μg to 2318μg

  19. Moessbauer and X-ray Diffraction Investigations of Sn-containing Binary and Ternary Electrodeposited Alloys from a Gluconate Bath

    International Nuclear Information System (INIS)

    Kuzmann, E.; Stichleutner, S.; Homonnay, Z.; Vertes, A.; Doyle, O.; Chisholm, C.U.; El-Sharif, M.

    2005-01-01

    Constant current technique was applied to electrodeposit tin-containing coatings such as tin-cobalt (Sn-Co), tin-iron (Sn-Fe) and a novel tin-cobalt-iron (Sn-Co-Fe) from a gluconate bath. The effect of plating parameters (current density, deposition time at an electrolyte temperature of 60 deg. C and pH=7.0) on phase composition, crystal structure and magnetic anisotropy of alloy deposits has been investigated mainly by 57Fe CEMS, 119Sn CEMS and transmission Moessbauer Spectroscopy as well as XRD. 57Fe and 119Sn CEM spectra and XRD reflect that the dominant phases of the deposits are orthorhombic Co3Sn2, tetragonal FeSn2 or amorphous Fe-Sn and amorphous Sn-Co-Fe in Sn-Co, Sn-Fe and Sn-Co-Fe coatings, respectively. Furthermore, the relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases decreases continuously with increasing current density in all Fe-containing deposits. At the same time, no essential change in the magnetic anisotropy can be found with the plating time. 119Sn spectra reveal the presence of small amount of β-Sn besides the main phases in Sn-Fe and in the Sn-Co coatings. Magnetically split 119Sn spectra reflecting transferred hyperfine field were observed in the case of Co-Sn-Fe coatings

  20. Moessbauer and X-ray Diffraction Investigations of Sn-containing Binary and Ternary Electrodeposited Alloys from a Gluconate Bath

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmann, E; Stichleutner, S; Homonnay, Z; Vertes, A [Department of Nulear Chemistry, Hungarian Academy of Sciences, Eoetvoes University, Budapest (Hungary); Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Eoetvoes University, Budapest (Hungary); Doyle, O; Chisholm, C U; El-Sharif, M [Glasgow Caledonian University, Glasgow, Scotland (United Kingdom)

    2005-04-26

    Constant current technique was applied to electrodeposit tin-containing coatings such as tin-cobalt (Sn-Co), tin-iron (Sn-Fe) and a novel tin-cobalt-iron (Sn-Co-Fe) from a gluconate bath. The effect of plating parameters (current density, deposition time at an electrolyte temperature of 60 deg. C and pH=7.0) on phase composition, crystal structure and magnetic anisotropy of alloy deposits has been investigated mainly by 57Fe CEMS, 119Sn CEMS and transmission Moessbauer Spectroscopy as well as XRD. 57Fe and 119Sn CEM spectra and XRD reflect that the dominant phases of the deposits are orthorhombic Co3Sn2, tetragonal FeSn2 or amorphous Fe-Sn and amorphous Sn-Co-Fe in Sn-Co, Sn-Fe and Sn-Co-Fe coatings, respectively. Furthermore, the relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases decreases continuously with increasing current density in all Fe-containing deposits. At the same time, no essential change in the magnetic anisotropy can be found with the plating time. 119Sn spectra reveal the presence of small amount of {beta}-Sn besides the main phases in Sn-Fe and in the Sn-Co coatings. Magnetically split 119Sn spectra reflecting transferred hyperfine field were observed in the case of Co-Sn-Fe coatings.

  1. Enhancement of field emission and photoluminescence properties of graphene-SnO2 composite nanostructures.

    Science.gov (United States)

    Ding, Jijun; Yan, Xingbin; Li, Jun; Shen, Baoshou; Yang, Juan; Chen, Jiangtao; Xue, Qunji

    2011-11-01

    In this study, the SnO(2) nanostructures and graphene-SnO(2) (G-SnO(2)) composite nanostructures were prepared on n-Si (100) substrates by electrophoretic deposition and magnetron sputtering techniques. The field emission of SnO(2) nanostructures is improved largely by depositing graphene buffer layer, and the field emission of G-SnO(2) composite nanostructures can also further be improved by decreasing sputtering time of Sn nanoparticles to 5 min. The photoluminescence (PL) spectra of the SnO(2) nanostructures revealed multipeaks, which are consistent with previous reports except for a new peak at 422 nm. Intensity of six emission peaks increased after depositing graphene buffer layer. Our results indicated that graphene can also be used as buffer layer acting as interface modification to simultaneity improve the field emission and PL properties of SnO(2) nanostructures effectively.

  2. Corrosion Behaviour of Sn-based Lead-Free Solders in Acidic Solution

    Science.gov (United States)

    Nordarina, J.; Mohd, H. Z.; Ahmad, A. M.; Muhammad, F. M. N.

    2018-03-01

    The corrosion properties of Sn-9(5Al-Zn), Sn-Cu and SAC305 were studied via potentiodynamic polarization method in an acidic solution of 1 M hydrochloric acid (HCl). Sn-9(5Al-Zn) produced different polarization profile compared with Sn-Cu and SAC305. The morphological analysis showed that small, deep grooves shaped of corrosion product formed on top of Sn-9(5Al-Zn) solder while two distinctive structures of closely packed and loosely packed corrosion product formed on top of Sn-Cu and SAC305 solder alloys. Phase analysis revealed the formations of various corrosion products such as SnO and SnO2 mainly dominant on surface of solder alloys after potentiodynamic polarization in 1 M hydrochloric acid (HCl).

  3. Effects of coating process on the characteristics of Ag-SnO2 contact materials

    International Nuclear Information System (INIS)

    Liu, X.M.; Wu, S.L.; Chu, Paul K.; Chung, C.Y.; Zheng, J.; Li, S.L.

    2006-01-01

    Good wettability between the SnO 2 and silver matrix can improve the electrical contact performance of Ag-SnO 2 materials. In this work, Ag was deposited onto the surface of Ti-doped SnO 2 particles using chemical plating to enhance the wettability. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the Ag-coated SnO 2 particles. Scanning electron microscopy (SEM), conductivity tests, differential thermal analysis (DTA), and thermogravimetric analysis (TGA) were performed on the Ag-SnO 2 materials. Our results reveal that the chemical plating process can enhance the wettability between the Ti-doped SnO 2 particles and Ag matrix, and the Ag-coated SnO 2 particles are uniformly distributed in the Ag matrix. Both the thermal and electrical conductivity of the Ag-SnO 2 materials are significantly improved

  4. Ultrasonic synthesis of In-doped SnS nanoparticles and their physical properties

    Science.gov (United States)

    Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

    2018-05-01

    Indium (In)-doped Tin (II) Sulfide (SnS) nanoparticles (NPs) were synthesized by an ultra-sonication method and their optical, electrical, dielectric and photocatalytic properties were investigated. XRD patterns of the obtained NPs indicated formation of orthorhombic polycrystalline SnS. Field emission scanning electron microscopy exhibited flower-like NPs with particle sizes below 100 nm for both SnS and In-doped SnS samples. Optical analysis showed a decrease in energy band gap of SnS NPs upon In doping. In addition, electrical results demonstrated p-type nature of the synthesized SnS NPs and enhanced electrical conductivity of the NPs due to increased tin vacancy. Dielectric experiments on SnS NPs suggested an electronic polarizations effect to be responsible for changing dielectric properties of the particles, in terms of frequency. Finally, photocatalytic experiments revealed that high degradation power can be obtained using In-doped SnS NPs.

  5. Negative heat capacities in central Xe+Sn reactions

    International Nuclear Information System (INIS)

    Le Neindre, N.; Bougault, R.; Gulminelli, F.

    2000-02-01

    In this study the fluctuation method is applied to the 32-50 A.MeV Xe + Sn central collisions detected with the INDRA multidetector. This method based on kinetic energy fluctuations allows the authors to provide information on the liquid gas phase transition in nuclear multifragmentation. In the case of Xe + Sn central reactions a divergence in the total heat capacity is observed. This divergence corresponds to large fluctuations on the detected fragment partitions. A negative heat capacity branch is measured and so tends to confirm the observation of a first order phase transition in heavy-ion collisions. (A.C.)

  6. Optical and electrochromic properties of Sn:WO3 cermets

    International Nuclear Information System (INIS)

    Ashrit, P.V.; Bader, G.; Girouard, F.E.; Truong, V.V.

    1989-01-01

    This paper discusses optical and electrochromic properties of Sn:WO 3 cermets deposited by alternate layer thermal deposition. These cermets exhibit electrical and optical behavior in the as deposited state. The inclusion of Sn in the WO 3 matrix enhances the Electrical conductivity of the system and renders them fairly transparent in the visible region. The electrochromic behavior of such systems is studied under both proton and Li + ion injection. The good conductivity and good transmission combined with good electrochromic characteristics of these systems indicate the possibility of utilizing this type of cermet for the dual role of transparent conductor (TC) and electrochromic (EC) layer

  7. Preparation of SnSe thin films by encapsulated selenization

    International Nuclear Information System (INIS)

    Sabar D. Hutagalung; Samsudi Sakrani; Yussof Wahab

    1994-01-01

    Tin selenide thin films were prepared by encapsulated selenization. A stacked layer of evaporated Sn and Se films were annealed in a carbon block at temperatures 100 - 500 degree Celsius for 3 hours. X-ray analysis and SEM (Scanning electron) micrograph results showed that SnSe was initially formed at 150 degree Celsius with crystal size 30.0 nm and reached optimum formation at 200 daximum of 57.4 % yield of 5-decene. Other factors such as reaction temperatures, types of solvent and wt% of rhenium loadings influence the activity of the catalytic system

  8. Nanocrystalline SnO2 by liquid pyrolysis

    Directory of Open Access Journals (Sweden)

    Morante, J. R.

    2000-08-01

    Full Text Available Liquid pyrolysis is presented as a new production method of SnO2 nanocrystalline powders suitable for gas sensor devices. The method is based on a pyrolytic reaction of high tensioned stressed drops of an organic solution of SnCl4•5(H2O. The main advantages of the method are its capability to produce SnO2 nanopowders with high stability, its accurate control over the grain size and other structural characteristics, its high level of repeatability and its low industrialization implementation cost. The characterization of samples of SnO2 nanoparticles obtained by liquid pyrolysis in the range between 200ºC and 900ºC processing temperature is carried out by X-ray diffraction, transmission electron microscopy, Raman and X-ray photoelectron spectroscopy. Results are analyzed and discussed so as to validate the advantages of the liquid pyrolysis method.La pirólisis líquida se presenta como un nuevo método para producir SnO2 nanocristalino en polvo ideal para sensores de gas. El método se basa en una reacción pirolítica de gotas altamente tensionadas procedentes de una solución orgánica de SnCl4•5(H2O. Las principales ventajas del método son la capacidad para producir nanopartículas de SnO2 con una gran estabilidad, el preciso control sobre el tamaño de grano y sobre otras características estructurales, el alto nivel de repetibilidad y el bajo coste en su implementación industrial.La caracterización de las muestras de las nanopartículas de SnO2 obtenidas por pirólisis líquida en un rango de temperatura de procesado que va de 200ºC a 900ºC se ha realizado mediante difracción de rayos X, microscopía electrónica de transmisión, espectroscopía Raman y espectroscopía fotoelectrónica de rayos X. Los resultados se han analizado y discutido. Éstos validan las ventajas del método de la pirólisis líquida.

  9. First SN Discoveries from the Dark Energy Survey

    Science.gov (United States)

    Abbott, T.; Abdalla, F.; Achitouv, I.; Ahn, E.; Aldering, G.; Allam, S.; Alonso, D.; Amara, A.; Annis, J.; Antonik, M.; Aragon-Salamanca, A.; Armstrong, R.; Ashall, C.; Asorey, J.; Bacon, D.; Balbinot, E.; Banerji, M.; Barbary, K.; Barkhouse, W.; Baruah, L.; Bauer, A.; Bechtol, K.; Becker, M.; Bender, R.; Benoist, C.; Benoit-Levy, A.; Bernardi, M.; Bernstein, G.; Bernstein, J. P.; Bernstein, R.; Bertin, E.; Beynon, E.; Bhattacharya, S.; Biesiadzinski, T.; Biswas, R.; Blake, C.; Bloom, J. S.; Bocquet, S.; Brandt, C.; Bridle, S.; Brooks, D.; Brown, P. J.; Brunner, R.; Buckley-Geer, E.; Burke, D.; Burkert, A.; Busha, M.; Campa, J.; Campbell, H.; Cane, R.; Capozzi, D.; Carlstrom, J.; Carnero Rosell, A.; Carollo, M.; Carrasco-Kind, M.; Carretero, J.; Carter, M.; Casas, R.; Castander, F. J.; Chen, Y.; Chiu, I.; Chue, C.; Clampitt, J.; Clerkin, L.; Cohn, J.; Colless, M.; Copeland, E.; Covarrubias, R. A.; Crittenden, R.; Crocce, M.; Cunha, C.; da Costa, L.; d'Andrea, C.; Das, S.; Das, R.; Davis, T. M.; Deb, S.; DePoy, D.; Derylo, G.; Desai, S.; de Simoni, F.; Devlin, M.; Diehl, H. T.; Dietrich, J.; Dodelson, S.; Doel, P.; Dolag, K.; Efstathiou, G.; Eifler, T.; Erickson, B.; Eriksen, M.; Estrada, J.; Etherington, J.; Evrard, A.; Farrens, S.; Fausti Neto, A.; Fernandez, E.; Ferreira, P. C.; Finley, D.; Fischer, J. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Furlanetto, C.; Garcia-Bellido, J.; Gaztanaga, E.; Gelman, M.; Gerdes, D.; Giannantonio, T.; Gilhool, S.; Gill, M.; Gladders, M.; Gladney, L.; Glazebrook, K.; Gray, M.; Gruen, D.; Gruendl, R.; Gupta, R.; Gutierrez, G.; Habib, S.; Hall, E.; Hansen, S.; Hao, J.; Heitmann, K.; Helsby, J.; Henderson, R.; Hennig, C.; High, W.; Hirsch, M.; Hoffmann, K.; Holhjem, K.; Honscheid, K.; Host, O.; Hoyle, B.; Hu, W.; Huff, E.; Huterer, D.; Jain, B.; James, D.; Jarvis, M.; Jarvis, M. J.; Jeltema, T.; Johnson, M.; Jouvel, S.; Kacprzak, T.; Karliner, I.; Katsaros, J.; Kent, S.; Kessler, R.; Kim, A.; Kim-Vy, T.; King, L.; Kirk, D.; Kochanek, C.; Kopp, M.; Koppenhoefer, J.; Kovacs, E.; Krause, E.; Kravtsov, A.; Kron, R.; Kuehn, K.; Kuemmel, M.; Kuhlmann, S.; Kunder, A.; Kuropatkin, N.; Kwan, J.; Lahav, O.; Leistedt, B.; Levi, M.; Lewis, P.; Liddle, A.; Lidman, C.; Lilly, S.; Lin, H.; Liu, J.; Lopez-Arenillas, C.; Lorenzon, W.; LoVerde, M.; Ma, Z.; Maartens, R.; Maccrann, N.; Macri, L.; Maia, M.; Makler, M.; Manera, M.; Maraston, C.; March, M.; Markovic, K.; Marriner, J.; Marshall, J.; Marshall, S.; Martini, P.; Marti Sanahuja, P.; Mayers, J.; McKay, T.; McMahon, R.; Melchior, P.; Merritt, K. W.; Merson, A.; Miller, C.; Miquel, R.; Mohr, J.; Moore, T.; Mortonson, M.; Mosher, J.; Mould, J.; Mukherjee, P.; Neilsen, E.; Ngeow, C.; Nichol, R.; Nidever, D.; Nord, B.; Nugent, P.; Ogando, R.; Old, L.; Olsen, J.; Ostrovski, F.; Paech, K.; Papadopoulos, A.; Papovich, C.; Patton, K.; Peacock, J.; Pellegrini, P. S. S.; Peoples, J.; Percival, W.; Perlmutter, S.; Petravick, D.; Plazas, A.; Ponce, R.; Poole, G.; Pope, A.; Refregier, A.; Reyes, R.; Ricker, P.; Roe, N.; Romer, K.; Roodman, A.; Rooney, P.; Ross, A.; Rowe, B.; Rozo, E.; Rykoff, E.; Sabiu, C.; Saglia, R.; Sako, M.; Sanchez, A.; Sanchez, C.; Sanchez, E.; Sanchez, J.; Santiago, B.; Saro, A.; Scarpine, V.; Schindler, R.; Schmidt, B. P.; Schmitt, R. L.; Schubnell, M.; Seitz, S.; Senger, R.; Sevilla, I.; Sharp, R.; Sheldon, E.; Sheth, R.; Smith, R. C.; Smith, M.; Snigula, J.; Soares-Santos, M.; Sobreira, F.; Song, J.; Soumagnac, M.; Spinka, H.; Stebbins, A.; Stoughton, C.; Suchyta, E.; Suhada, R.; Sullivan, M.; Sun, F.; Suntzeff, N.; Sutherland, W.; Swanson, M. E. C.; Sypniewski, A. J.; Szepietowski, R.; Talaga, R.; Tarle, G.; Tarrant, E.; Balan, S. Thaithara; Thaler, J.; Thomas, D.; Thomas, R. C.; Tucker, D.; Uddin, S. A.; Ural, S.; Vikram, V.; Voigt, L.; Walker, A. R.; Walker, T.; Wechsler, R.; Weinberg, D.; Weller, J.; Wester, W.; Wetzstein, M.; White, M.; Wilcox, H.; Wilman, D.; Yanny, B.; Young, J.; Zablocki, A.; Zenteno, A.; Zhang, Y.; Zuntz, J.

    2012-12-01

    The Dark Energy Survey (DES) report the discovery of the first set of supernovae (SN) from the project. Images were observed as part of the DES Science Verification phase using the newly-installed 570-Megapixel Dark Energy Camera on the CTIO Blanco 4-m telescope by observers J. Annis, E. Buckley-Geer, and H. Lin. SN observations are planned throughout the observing campaign on a regular cadence of 4-6 days in each of the ten 3-deg2 fields in the DES griz filters.

  10. The experimental and shell model approach to 100Sn

    International Nuclear Information System (INIS)

    Grawe, H.; Maier, K.H.; Fitzgerald, J.B.; Heese, J.; Spohr, K.; Schubart, R.; Gorska, M.; Rejmund, M.

    1995-01-01

    The present status of experimental approach to 100 Sn and its shell model structure is given. New developments in experimental techniques, such as low background isomer spectroscopy and charged particle detection in 4π are surveyed. Based on recent experimental data shell model calculations are used to predict the structure of the single- and two-nucleon neighbours of 100 Sn. The results are compared to the systematic of Coulomb energies and spin-orbit splitting and discussed with respect to future experiments. (author). 51 refs, 11 figs, 1 tab

  11. Portuguese granites associated with Sn-W and Au mineralizations

    OpenAIRE

    Ana M.R. Neiva

    2002-01-01

    In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional cr...

  12. Electric field gradient studies in SnSe

    Energy Technology Data Exchange (ETDEWEB)

    Pal, G. [IUC, DAE Facilities (India); Sebastian, K.C. [M.S. University, Physics Department (India); Chintalapudi, S.N. [IUC, DAE Facilities (India); Somayajulu, D.R.S. [M.S. University, Physics Department (India)

    1999-09-15

    The EFG in IV-VI compound semiconductor SnSe was studied using two hyperfine interaction techniques, namely, TDPAC and Moessbauer spectroscopy. The EFG in this material increases sharply up to 300 K and thereafter at higher temperatures it gets saturated. However, the conductivity increases steadily at all the temperatures. The conductivity curve has two slopes. The first portion is due to the population of shallow Cd acceptor levels. Thus, in SnSe also the variation of the EFG with temperature is complex, as in other medium-gap semiconductors.

  13. Electric field gradient studies in SnSe

    International Nuclear Information System (INIS)

    Pal, G.; Sebastian, K.C.; Chintalapudi, S.N.; Somayajulu, D.R.S.

    1999-01-01

    The EFG in IV-VI compound semiconductor SnSe was studied using two hyperfine interaction techniques, namely, TDPAC and Moessbauer spectroscopy. The EFG in this material increases sharply up to 300 K and thereafter at higher temperatures it gets saturated. However, the conductivity increases steadily at all the temperatures. The conductivity curve has two slopes. The first portion is due to the population of shallow Cd acceptor levels. Thus, in SnSe also the variation of the EFG with temperature is complex, as in other medium-gap semiconductors

  14. Tietoinen läsnäolo toimintaterapiassa : Opas toimintaterapeuteille

    OpenAIRE

    Ritola, Noora; Hätälä, Jenni

    2013-01-01

    Tietoinen läsnäolo ja sen harjoittaminen on ajankohtainen nykyajan kiireisessä ja tulostavoitteisessa elämän rytmissä. Stressillä on negatiivisia vaikutuksia terveyteen ja stressiperäisiä sairauksia esiintyy paljon. Osaamme yleensä pitää huolta kehomme terveydestä ja hyvinvoinnista, mutta meillä on usein hyvin vähän tietoa siitä, miten mieltä voi harjoittaa. Tietoisen läsnäolon harjoittaminen opettaa mielentaitoja, kuten itsetuntemusta ja stressinhallintaa. Sen avulla opimme kohdistamaan huom...

  15. Sn-Beta catalysed conversion of hemicellulosic sugars

    DEFF Research Database (Denmark)

    Holm, Martin; Pagán-Torres, Yomaira J.; Shunmugavel, Saravanamurugan

    2012-01-01

    are observed for the pentoses. This finding is in accordance to a reaction pathway that involves the retro aldol condensation of the sugars to form a triose and glycolaldehyde for the pentoses, and two trioses for hexoses. When reacting glycolaldehyde (formally a C2-sugar) in the presence of Sn-Beta, aldol...... condensation occurs, leading to the formation of methyl lactate, methyl vinylglycolate and methyl 2-hydroxy-4-methoxybutanoate. In contrast, when converting the sugars in water at low temperatures (100 °C), Sn-Beta catalyses the isomerisation of sugars (ketose–aldose epimers), rather than the formation...

  16. Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

    CERN Document Server

    Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

    2001-01-01

    Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

  17. Solid Liquid Interdiffusion Bonding of (Pb, Sn)Te Thermoelectric Modules with Cu Electrodes Using a Thin-Film Sn Interlayer

    Science.gov (United States)

    Chuang, T. H.; Lin, H. J.; Chuang, C. H.; Yeh, W. T.; Hwang, J. D.; Chu, H. S.

    2014-12-01

    A (Pb, Sn)Te thermoelectric element plated with a Ni barrier layer and a Ag reaction layer has been joined with a Cu electrode coated with Ag and Sn thin films using a solid-liquid interdiffusion bonding method. This method allows the interfacial reaction between Ag and Sn such that Ag3Sn intermetallic compounds form at low temperature and are stable at high temperature. In this study, the bonding strength was about 6.6 MPa, and the specimens fractured along the interface between the (Pb, Sn)Te thermoelectric element and the Ni barrier layer. Pre-electroplating a film of Sn with a thickness of about 1 μm on the thermoelectric element and pre-heating at 250°C for 3 min ensures the adhesion between the thermoelectric material and the Ni barrier layer. The bonding strength is thus increased to a maximal value of 12.2 MPa, and most of the fractures occur inside the thermoelectric material. During the bonding process, not only the Ag3Sn intermetallics but also Cu6Sn5 forms at the Ag3Sn/Cu interface, which transforms into Cu3Sn with increases in the bonding temperature or bonding time.

  18. P-type SnO thin films and SnO/ZnO heterostructures for all-oxide electronic and optoelectronic device applications

    Energy Technology Data Exchange (ETDEWEB)

    Saji, Kachirayil J. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Govt. Victoria College, University of Calicut, Palakkad 678 001 (India); Venkata Subbaiah, Y.P. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Yogi Vemana University, Kadapa, Andhra Pradesh 516003 (India); Tian, Kun [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

    2016-04-30

    Tin monoxide (SnO) is considered as one of the most important p-type oxides available to date. Thin films of SnO have been reported to possess both an indirect bandgap (~ 0.7 eV) and a direct bandgap (~ 2.8 eV) with quite high hole mobility (~ 7 cm{sup 2}/Vs) values. Moreover, the hole density in these films can be tuned from 10{sup 15}–10{sup 19} cm{sup −3} just by controlling the thin film deposition parameters. Because of the above attributes, SnO thin films offer great potential for fabricating modern electronic and optoelectronic devices. In this article, we are reviewing the most recent developments in this field and also presenting some of our own results on SnO thin films grown by pulsed laser deposition technique. We have also proposed a p–n heterostructure comprising of p-type SnO and n-type ZnO which can pave way for realizing next-generation, all-oxide transparent electronic devices. - Highlights: • We reviewed recent developments on p-type SnO thin film research. • Discussed the optical and electrical properties of SnO thin films • Bipolar conduction in SnO is discussed. • Optoelectronic properties of SnO–ZnO composite system are discussed. • Proposed SnO–ZnO heterojunction band structure.

  19. Adsorption and oxidation of acetaldehyde on carbon supported Pt, PtSn and PtSn-based trimetallic catalysts by in situ Fourier transform infrared spectroscopy

    Science.gov (United States)

    Beyhan, Seden; Léger, Jean-Michel; Kadırgan, Figen

    2013-11-01

    The adsorption and oxidation of acetaldehyde on carbon supported Pt, Pt90Sn10 and Pt80Sn10M10 (M = Ni, Co, Rh, Pd) catalysts have been investigated by using in situ Fourier transform infrared (FTIR) spectroscopy. The result revealed that Pt90Sn10/C catalyst is not very efficient for the conversion of acetaldehyde to CO2 due to the weak adsorption of acetaldehyde in the presence of Sn. However, the addition of a third metal to Pt--Sn facilitates the C-C bond cleavage of acetaldehyde. It seems that acetaldehyde is adsorbed dissociatively on the surface of Pt80Sn10Ni10/C, Pt80Sn10Co10/C, Pt80Sn10Rh10/C catalysts, producing CH3 and CHO adsorbate species, which can be further oxidized to CO2. However, the pathway forming CO2 for Pt80Sn10Pd10/C catalyst mainly originates from the oxidation of CH3CO species. Thus, the presence of third metal in the PtSn catalyst has a strong impact upon the acetaldehyde adsorption behaviour and its reaction products.

  20. Controlling the Sn-C bonds content in SnO2@CNTs composite to form in situ pulverized structure for enhanced electrochemical kinetics.

    Science.gov (United States)

    Cheng, Yayi; Huang, Jianfeng; Qi, Hui; Cao, Liyun; Luo, Xiaomin; Li, Jiayin; Xu, Zhanwei; Yang, Jun

    2017-12-07

    The Sn-C bonding content between the SnO 2 and CNTs interface was controlled by the hydrothermal method and subsequent heat treatment. Electrochemical analysis found that the SnO 2 @CNTs with high Sn-C bonding content exhibited much higher capacity contribution from alloying and conversion reaction compared with the low content of Sn-C bonding even after 200 cycles. The high Sn-C bonding content enabled the SnO 2 nanoparticles to stabilize on the CNTs surface, realizing an in situ pulverization process of SnO 2 . The in situ pulverized structure was beneficial to maintain the close electrochemical contact of the working electrode during the long-term cycling and provide ultrafast transfer paths for lithium ions and electrons, which promoted the alloying and conversion reaction kinetics greatly. Therefore, the SnO 2 @CNTs composite with high Sn-C bonding content displayed highly reversible alloying and conversion reaction. It is believed that the composite could be used as a reference for design chemically bonded metal oxide/carbon composite anode materials in lithium-ion batteries.

  1. Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

    OpenAIRE

    R. Nurzulaikha; H.N. Lim; I. Harrison; S.S. Lim; A. Pandikumar; N.M. Huang; S.P. Lim; G.S.H. Thien; N. Yusoff; I. Ibrahim

    2015-01-01

    A graphene-tin oxide (G-SnO2) nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). A homogeneous deposition of SnO2 nanoparticles with an average partic...

  2. α-Eleostearic acid-containing triglycerides for a continuous assay to determine lipase sn-1 and sn-3 regio-preference.

    Science.gov (United States)

    El Alaoui, Meddy; Soulère, Laurent; Noiriel, Alexandre; Queneau, Yves; Abousalham, Abdelkarim

    2017-08-01

    Lipases are essentially described as sn-1 and sn-3 regio-selective. Actually few methods are available to measure this lipase regio-selectivity, moreover they require chiral chromatography analysis or specific derivations which are discontinuous and time consuming. In this study we describe a new, convenient, sensitive and continuous spectrophotometric method to screen lipases regio-selectivity using synthetic triglycerides (TG) containing α-eleostearic acid (9Z, 11E, 13E-octadecatrienoic acid) either at the sn-1 position [1-α-eleostearoyl-2,3-octadecyl-sn-glycerol (sn-EOO)] or at the sn-3 position [1,2-octadecyl-3-α-eleostearoyl-sn-glycerol (sn-OOE)] and coated onto the wells of microtiter plates. A non-hydrolysable ether bond, with a non UV-absorbing alkyl chain, was introduced at the other sn positions to prevent acyl chain migration during TG synthesis or lipolysis. The synthesis of TG containing α-eleostearic acid was performed from S-glycidol in six steps to obtain sn-EOO and in five steps to sn-OOE. The α-eleostearic acid conjugated triene constitutes an intrinsic chromophore and, consequently, confers the strong UV absorption properties of this free fatty acid as well as of the TG harboring it. The lipase activity on coated sn-EOO or sn-OOE was measured by the increase in the absorbance at 272nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. Human and porcine pancreatic lipases, guinea pig pancreatic lipase related protein 2, Thermomyces lanuginosus lipase, Candida antarctica lipase A and Candida antarctica lipase B were all used to validate the assay. This continuous high-throughput screening method could determine directly without any processes after lipolysis the regio-selectivity of various lipases. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys

    International Nuclear Information System (INIS)

    Lopes, E.S.N.; Contieri, R.J.; Caram, R.; Costa, A.M.S.

    2010-01-01

    The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

  4. Superconductivity optimization and phase formation kinetics study of internal-Sn Nb{sub 3}Sn superconducting wires

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chaowu

    2007-07-15

    Superconductors Nb{sub 3}Sn wires are one of the most applicable cryogenic superconducting materials and the best choice for high-field magnets exceeding 10 T. One of the most significant utilization is the ITER project which is regarded as the hope of future energy source. The high-Cu composite designs with smaller number of sub-element and non-reactive diffusion barrier, and the RRP (Restacked Rod Process) internal-Sn technology are usually applied for the wire manufacturing. Such designed and processed wires were supplied by MSA/Alstom and WST/NIN in this research. The systematic investigation on internal-Sn superconducting wires includes the optimization of heat treatment (HT) conditions, phase formation and its relation with superconductivity, microstructure analysis, and the phase formation kinetics. Because of the anfractuosity of the configuration design and metallurgical processing, the MF wires are not sufficient for studying a sole factor effect on superconductivity. Therefore, four sets of mono-element (ME) wires with different Sn ratios and different third-element addition were designed and fabricated in order to explore the relationship between phase formation and superconducting performances, particularly the A15 layer growth kinetics. Different characterization technic have been used (magnetization measurements, neutron diffraction and SEM/TEM/EDX analysis). The A15 layer thicknesses of various ME samples were measured and carried out linear and non-linear fits by means of two model equations. The results have clearly demonstrated that the phase formation kinetics of Nb{sub 3}Sn solid-state reaction is in accordance with an n power relation and the n value is increased with the increase of HT temperature and the Sn ratio in the wire composite. (author)

  5. Transport and NMR characteristics of the skutterudite-related compound Ca3Rh4Sn13

    Science.gov (United States)

    Tseng, C. W.; Kuo, C. N.; Li, B. S.; Wang, L. M.; Gippius, A. A.; Kuo, Y. K.; Lue, C. S.

    2018-02-01

    We report the electronic properties of the Yb3Rh4Sn13-type single crystalline Ca3Rh4Sn13 by means of the electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as 119Sn nuclear magnetic resonance (NMR) measurements. The negative sign of the Hall coefficient and Seebeck coefficient at low temperatures suggests that the n-type carriers dominate the electrical transport in Ca3Rh4Sn13, in contrast to the observations in Sr3Rh4Sn13 which has a p-type conduction. Such a finding indicates a significant difference in the electronic features between these two stannides. Furthermore, we analyzed the temperature-dependent 119Sn NMR spin-lattice relaxation rate for Ca3Rh4Sn13, (Sr0.7Ca0.3)3Rh4Sn13, and Sr3Rh4Sn13 to examine the change of the electronic Fermi-level density of states (DOS) in (Sr1-xCax)3Rh4Sn13. It indicates that the Sn 5s partial Fermi-level DOS enhances with increasing the Ca content, being consistent with the trend of the superconducting temperature. Since the total Fermi-level DOS usually obeys the same trend of the partial Fermi-level DOS, the NMR analysis provides microscopic evidence for the correlation between the electronic DOS and superconductivity of the (Sr1-xCax)3Rh4Sn13 system.

  6. Electrochemical studies of CNT/Si–SnSb nanoparticles for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Nithyadharseni, P. [Department of Physics, Bannari Amman Institute of Technology, Sathyamangalam 638402 (India); Department of Physics, Advanced Batteries Lab, National University of Singapore, 117542 (Singapore); Reddy, M.V., E-mail: phymvvr@nus.edu.sg [Department of Physics, Advanced Batteries Lab, National University of Singapore, 117542 (Singapore); Nalini, B., E-mail: lalin99@rediffmail.com [Department of Physics, Avinashilingam University for Women, Coimbatore 641043 (India); Ravindran, T.R. [Centre for Research in Nanotechnology, Karunya University, Coimbatore 641114 (India); Pillai, B.C.; Kalpana, M. [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India); Chowdari, B.V.R. [Department of Physics, Advanced Batteries Lab, National University of Singapore, 117542 (Singapore)

    2015-10-15

    Highlights: • Si added SnSb and CNT exhibits very low particle size of below 30 nm • A strong PL quenching due to the addition of Si to SnSb. • Electrochemical studies show CNT added SnSb shows good capacity retention. - Abstract: Nano-structured SnSb, SnSb–CNT, Si–SnSb and Si–SnSb–CNT alloys were synthesized from metal chlorides of Sn, Sb and Si via reductive co-precipitation technique using NaBH{sub 4} as reducing agent. The as prepared compounds were characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), Raman, Fourier transform infra-red (FTIR) and photoluminescence (PL) spectroscopy. The electrochemical performances of the compounds were characterized by galvanostatic cycling (GC) and cyclic voltammetry (CV). The Si–SnSb–CNT compound shows a high reversible capacity of 1200 mAh g{sup −1}. However, the rapid capacity fading was observed during cycling. In contrast, SnSb–CNT compound showed a high reversible capacity of 568 mAh g{sup −1} at 30th cycles with good cycling stability. The improved reversible capacity and cyclic performance of the SnSb–CNT compound could be attributed to the nanosacle dimension of SnSb particles and the structural advantage of CNTs.

  7. Effect of indium and antimony doping in SnS single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chaki, Sunil H., E-mail: sunilchaki@yahoo.co.in; Chaudhary, Mahesh D.; Deshpande, M.P.

    2015-03-15

    Highlights: • Single crystals growth of pure SnS, indium doped SnS and antimony doped SnS by direct vapour transport (DVT) technique. • Doping of In and Sb occurred in SnS single crystals by cation replacement. • The replacement mechanism ascertained by EDAX, XRD and substantiated by Raman spectra analysis. • Dopants concentration affects the optical energy bandgap. • Doping influences electrical transport properties. - Abstract: Single crystals of pure SnS, indium (In) doped SnS and antimony (Sb) doped SnS were grown by direct vapour transport (DVT) technique. Two doping concentrations of 5% and 15% each were employed for both In and Sb dopants. Thus in total five samples were studied viz., pure SnS (S1), 5% In doped SnS (S2), 15% In doped SnS (S3), 5% Sb doped SnS (S4) and 15% Sb doped SnS (S5). The grown single crystal samples were characterized by evaluating their surface microstructure, stoichiometric composition, crystal structure, Raman spectroscopy, optical and electrical transport properties using appropriate techniques. The d.c. electrical resistivity and thermoelectric power variations with temperature showed semiconducting and p-type nature of the as-grown single crystal samples. The room temperature Hall Effect measurements further substantiated the semiconducting and p-type nature of the as-grown single crystal samples. The obtained results are deliberated in detail.

  8. Liquidus Projection and Thermodynamic Modeling of a Sn-Ag-Zn System

    Science.gov (United States)

    Chen, Sinn-wen; Chiu, Wan-ting; Gierlotka, Wojciech; Chang, Jui-shen; Wang, Chao-hong

    2017-12-01

    Sn-Ag-Zn alloys are promising Pb-free solders. In this study, the Sn-Ag-Zn liquidus projection was determined, and the Sn-Ag-Zn thermodynamic modeling was developed. Various Sn-Ag-Zn alloys were prepared. Their as-cast microstructures and primary solidification phases were examined. The invariant reaction temperatures of the ternary Sn-Ag-Zn system were determined. The liquidus projection of the Sn-Ag-Zn ternary system was constructed. It was found that the Sn-Ag-Zn ternary system has eight primary solidification phases: ɛ2-AgZn3, γ-Ag5Zn8, β-AgZn, ζ-Ag4Sn, (Ag), ɛ1-Ag3Sn, β-(Sn) and (Zn) phases. There are eight ternary invariant reactions, and the liquid + (Ag) = β-AgZn + ζ-Ag4Sn reaction is of the highest temperature at 935.5 K. Thermodynamic modeling of the ternary Sn-Ag-Zn system was also carried out in this study based on the thermodynamic models of the three constituent binary systems and the experimentally determined liquidus projection. The liquidus projection and the isothermal sections are calculated. The calculated and experimentally determined liquidus projections are in good agreement.

  9. Thermodynamic, electronic, and magnetic properties of intrinsic vacancy defects in antiperovskite Ca3SnO

    Science.gov (United States)

    Batool, Javaria; Alay-e-Abbas, Syed Muhammad; Amin, Nasir

    2018-04-01

    The density functional theory based total energy calculations are performed to examine the effect of charge neutral and fully charged intrinsic vacancy defects on the thermodynamic, electronic, and magnetic properties of Ca3SnO antiperovskite. The chemical stability of Ca3SnO is evaluated with respect to binary compounds CaO, CaSn, and Ca2Sn, and the limits of atomic chemical potentials of Ca, Sn, and O atoms for stable synthesis of Ca3SnO are determined within the generalized gradient approximation parametrization scheme. The electronic properties of the pristine and the non-stoichiometric forms of this compound have been explored and the influence of isolated intrinsic vacancy defects (Ca, Sn, and O) on the structural, bonding, and electronic properties of non-stoichiometric Ca3SnO are analyzed. We also predict the possibility of achieving stable ferromagnetism in non-stoichiometric Ca3SnO by means of charge neutral tin vacancies. From the calculated total energies and the valid ranges of atomic chemical potentials, the formation energetics of intrinsic vacancy defects in Ca3SnO are evaluated for various growth conditions. Our results indicate that the fully charged calcium vacancies are thermodynamically stable under the permissible Sn-rich condition of stable synthesis of Ca3SnO, while tin and oxygen vacancies are found to be stable under the extreme Ca-rich condition.

  10. Thermodynamic assessment of the Sn-Co lead-free solder system

    Science.gov (United States)

    Liu, Libin; Andersson, Cristina; Liu, Johan

    2004-09-01

    The Sn-Co-Cu eutectic alloy can be a less expensive alternative for the Sn-Ag-Cu alloy. In order to find the eutectic solder composition of the Sn-Co-Cu system, the Sn-Co binary system has been thoroughly assessed with the calculation of phase diagram (CALPHAD) method. The liquid phase, the FCC and HCP Co-rich solid solution, and the BCT Sn-rich solid solution have been described by the Redlich-Kister model. The Hillert-Jarl-Inden model has been used to describe the magnetic contributions to Gibbs energy in FCC and HCP. The CoSn2, CoSn, Co3Sn2_β, and Co3Sn2_α phases have been treated as stoichiometric phases. A series of thermodynamic parameters have been obtained. The calculated phase diagram and thermodynamic properties are in good agreement with the experimental data. The obtained thermodynamic data was used to extrapolate the ternary Sn-Co-Cu phase diagram. The composition of the Sn-rich eutectic point of the Sn-Co-Cu system was found to be 224°C, 0.4% Co, and 0.7% Cu.

  11. The complex structure of liquid Cu{sub 6}Sn{sub 5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qin Jingyu; Gu Tingkun; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Southern Campus, Jinan 250061 (China); Liu Hui [Shandong High Performance Computing Center, Shandong University, Southern Campus, Jinan 250061 (China)

    2009-04-15

    By applying ab initio molecular dynamics simulation to liquid Cu{sub 6}Sn{sub 5} alloy, the hetero-coordination tendency is discovered by Bathia-Thornton partial correlation functions and a chemical short-range parameter. However the local structural environment of Sn in l-Cu{sub 6}Sn{sub 5} alloy resembles that of liquid Sn by Voronoi analysis. A new feature, i.e. a subpeak in between the first and second peaks, is discovered by the present method which implies that topologically disordered {beta}-Sn-type structural units may exist in l-Cu{sub 6}Sn{sub 5} alloy. The local density states of electrons show that both Cu-Sn and Sn-Sn bonding exist in l-Cu{sub 6}Sn{sub 5} alloy. This work suggests that chemical short-range order between unlike atoms and self-coordination between Sn atoms coexists in l-Cu{sub 6}Sn{sub 5} alloy.

  12. Highly Reproducible Sn-Based Hybrid Perovskite Solar Cells with 9% Efficiency

    NARCIS (Netherlands)

    Shao, Shuyan; Liu, Jian; Portale, Giuseppe; Fang, Hong-Hua; Blake, Graeme R.; ten Brink, Gert H.; Koster, L. Jan Anton; Loi, Maria Antonietta

    2018-01-01

    The low power conversion efficiency (PCE) of tin-based hybrid perovskite solar cells (HPSCs) is mainly attributed to the high background carrier density due to a high density of intrinsic defects such as Sn vacancies and oxidized species (Sn4+) that characterize Sn-based HPSCs. Herein, this study

  13. Nanoscale Cross-Point Resistive Switching Memory Comprising p-Type SnO Bilayers

    KAUST Repository

    Hota, Mrinal Kanti; Hedhili, Mohamed N.; Wang, Qingxiao; Melnikov, Vasily; Mohammed, Omar F.; Alshareef, Husam N.

    2015-01-01

    Reproducible low-voltage bipolar resistive switching is reported in bilayer structures of p-type SnO films. Specifically, a bilayer homojunction comprising SnOx (oxygen-rich) and SnOy (oxygen-deficient) in nanoscale cross-point (300 × 300 nm2

  14. Alloy Design and Property Evaluation of Ti-Mo-Nb-Sn Alloy for ...

    African Journals Online (AJOL)

    Ti-Mo alloy containing Nb and Sn were arc melted and composition analyzed by EDX. The XRD analysis indicates that the crystal structure and mechanical properties are sensitive to Sn concentration. A combination of Sn and Nb elements in synergy hindered formation athermal w phase and significantly enhanced b phase ...

  15. Cubic Crystal-Structured SnTe for Superior Li- and Na-Ion Battery Anodes.

    Science.gov (United States)

    Park, Ah-Ram; Park, Cheol-Min

    2017-06-27

    A cubic crystal-structured Sn-based compound, SnTe, was easily synthesized using a solid-state synthetic process to produce a better rechargeable battery, and its possible application as a Sn-based high-capacity anode material for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) was investigated. The electrochemically driven phase change mechanisms of the SnTe electrodes during Li and Na insertion/extraction were thoroughly examined utilizing various ex situ analytical techniques. During Li insertion, SnTe was converted to Li 4.25 Sn and Li 2 Te; meanwhile, during Na insertion, SnTe experienced a sequential topotactic transition to Na x SnTe (x ≤ 1.5) and conversion to Na 3.75 Sn and Na 2 Te, which recombined into the original SnTe phase after full Li and Na extraction. The distinctive phase change mechanisms provided remarkable electrochemical Li- and Na-ion storage performances, such as large reversible capacities with high Coulombic efficiencies and stable cyclabilities with fast C-rate characteristics, by preparing amorphous-C-decorated nanostructured SnTe-based composites. Therefore, SnTe, with its interesting phase change mechanisms, will be a promising alternative for the oncoming generation of anode materials for LIBs and NIBs.

  16. Structures, energetics and magnetic properties of (NiSn) n clusters ...

    Indian Academy of Sciences (India)

    The preference for tetrahedron unit of Ni3 Sn is seen in the lowest-energy configuration of these clusters. The multi-centre bonding between Ni atoms play an important role in stabilizing the stoichiometric Ni–Sn clusters. Doping of Sn atoms enhances the binding energy and reduces the ionization potential of nickel clusters.

  17. Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

    2016-08-15

    The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

  18. A novel method for massive synthesis of SnO2 nanowires

    Indian Academy of Sciences (India)

    Compositions of three reaction systems for synthesizing SnO2 nanowires by thermite reaction. Constituents (g) ... ing voltage and at a magnification of 3000. .... nanowires to obtain the distribution shown in figure 7. SnO2 ... The Sn drop sprayed ...

  19. Hurst's Exponent Determination for Radial Distribution Functions of In, Sn and In-40 wt%Sn Melt

    International Nuclear Information System (INIS)

    Zhou Yong-Zhi; Li Mei; Geng Hao-Ran; Yang Zhong-Xi; Sun Chun-Jing

    2011-01-01

    Hurst's exponent of radial distribution functions (RDFs) within the short-range scope of In, Sn and In-40 wt % Sn melts are determined by the rescaled range analysis method. Hurst's exponents H are between 0.94 and 0.97, which display long-range dependence. Within short-range scope, the number of particles from a reference particle belongs to fractional Brownian motion. After RDF serials are randomly scrambled, Hurst's exponents all dramatically dropped, which proves long-range dependence. H irregularly varies as the temperature rises, but the change tendency is not consistent with the correlation radius r c . (general)

  20. XRD and 119Sn Moessbauer spectroscopy characterization of SnSe obtained from a simple chemical route

    International Nuclear Information System (INIS)

    Bernardes-Silva, Ana Claudia; Mesquita, A.F.; Moura de Neto, E.; Porto, A.O.; Ardisson, J.D.; Lima, G.M. de; Lameiras, F.S.

    2005-01-01

    Crystalline tin selenide semiconductor was synthesized by a chemical route. Selenium powder reacted with potassium boronhydride, giving a soluble selenium species potassium seleniumhydride. The reaction of potassium seleniumhydride with tin chloride produced crystalline tin selenide, which was characterized by X-ray diffraction, 119 Sn Moessbauer spectroscopy and scanning electronic microscopy. The material was thermally treated, in nitrogen flow, at 300 and 600 deg. C for 2 h and the particle size evolution was studied by X-ray diffraction. The X-ray diffraction and 119 Sn Moessbauer results showed that a mixture of tin oxides and orthorhombic tin selenide was obtained

  1. 3D Flower-Like Hierarchitectures Constructed by SnS/SnS2 Heterostructure Nanosheets for High-Performance Anode Material in Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Zhiguo Wu

    2015-01-01

    Full Text Available Sn chalcogenides, including SnS, Sn2S3, and SnS2, have been extensively studied as anode materials for lithium batteries. In order to obtain one kind of high capacity, long cycle life lithium batteries anode materials, three-dimensional (3D flower-like hierarchitectures constructed by SnS/SnS2 heterostructure nanosheets with thickness of ~20 nm have been synthesized via a simple one-pot solvothermal method. The obtained samples exhibit excellent electrochemical performance as anode for Li-ion batteries (LIBs, which deliver a first discharge capacity of 1277 mAhg−1 and remain a reversible capacity up to 500 mAhg−1 after 50 cycles at a current of 100 mAg−1.

  2. Isospin Character of the Pygmy Dipole Resonance in Sn-124

    NARCIS (Netherlands)

    Endres, J.; Litvinova, E.; Savran, D.; Butler, P. A.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R. -D.; Kruecken, R.; Lagoyannis, A.; Pietralla, N.; Ponomarev, V. Yu; Popescu, L.; Ring, P.; Scheck, M.; Sonnabend, K.; Stoica, V. I.; Wörtche, H. J.; Zilges, A.

    2010-01-01

    The pygmy dipole resonance has been studied in the proton-magic nucleus Sn-124 with the (alpha, alpha'gamma) coincidence method at E-alpha = 136 MeV. The comparison with results of photon-scattering experiments reveals a splitting into two components with different structure: one group of states

  3. Review of sn-2 palmitate oil implications for infant health.

    Science.gov (United States)

    Bar-Yoseph, Fabiana; Lifshitz, Yael; Cohen, Tzafra

    2013-09-01

    Human milk provides the optimal balanced nutrition for the growing infant in the first months after birth. The human mammary gland has evolved with unusual pathways, resulting in a specific positioning of fatty acids at the outer sn-1 and sn-3, and center sn-2 of the triacylglyceride, which is different from the triglycerides in other human tissues and plasma. The development of structured triglycerides enables mimicking the composition as well as structure of human milk fat in infant formulas. Studies conducted two decades ago, together with very recent studies, have provided increasing evidence that this unusual positioning of 16:0 in human milk triglycerides has a significant role for infant health in different directions, such as fat and calcium absorption, bone health, intestinal flora and infant comfort. This review aims to unravel the relevance of human milk triglyceride sn-2 16:0 for intestinal health and inflammatory pathways and for other post-absorption effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. SN 2010U: A LUMINOUS NOVA IN NGC 4214

    International Nuclear Information System (INIS)

    Humphreys, Roberta M.; Helton, L. Andrew; Prieto, Jose L.; Rosenfield, Philip; Williams, Benjamin; Murphy, Jeremiah; Dalcanton, Julianne; Gilbert, Karoline; Kochanek, Christopher S.; Stanek, K. Z.; Khan, Rubab; Szczygiel, Dorota; Mogren, Karen; Fesen, Robert A.; Milisavljevic, Dan

    2010-01-01

    The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

  5. THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED

    Energy Technology Data Exchange (ETDEWEB)

    Folatelli, Gastón; Bersten, Melina C.; Benvenuto, Omar G. [Instituto de Astrofísica de La Plata (Argentina); Kuncarayakti, Hanindyo [Millennium Institute of Astrophysics (MAS), Casilla 36-D, Santiago (Chile); Maeda, Keiichi; Nomoto, Ken’ichi, E-mail: gaston@fcaglp.unlp.edu.ar [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2015-10-01

    Hubble Space Telescope observations of the site of the supernova (SN) SN 2008ax obtained in 2011 and 2013 reveal that the possible progenitor object detected in pre-explosion images was in fact multiple. Four point sources are resolved in the new, higher-resolution images. We identify one of the sources with the fading SN. The other three objects are consistent with single supergiant stars. We conclude that their light contaminated the previously identified progenitor candidate. After subtraction of these stars, the progenitor appears to be significantly fainter and bluer than previously measured. Post-explosion photometry at the SN location indicates that the progenitor object has disappeared. If single, the progenitor is compatible with a supergiant star of B to mid-A spectral type, while a Wolf–Rayet (W-R) star would be too luminous in the ultraviolet to account for the observations. Moreover, our hydrodynamical modeling shows that the pre-explosion mass was 4–5 M{sub ⊙} and the radius was 30–50 R{sub ⊙}, which is incompatible with a W-R progenitor. We present a possible interacting binary progenitor computed with our evolutionary models that reproduces all the observational evidence. A companion star as luminous as an O9–B0 main-sequence star may have remained after the explosion.

  6. Neutrino spectrum from SN 1987A and from cosmic supernovae

    International Nuclear Information System (INIS)

    Yueksel, Hasan; Beacom, John F.

    2007-01-01

    The detection of neutrinos from SN 1987A by the Kamiokande-II and Irvine-Michigan-Brookhaven detectors provided the first glimpse of core collapse in a supernova, complementing the optical observations and confirming our basic understanding of the mechanism behind the explosion. One long-standing puzzle is that, when fitted with thermal spectra, the two independent detections do not seem to agree with either each other or typical theoretical expectations. We assess the compatibility of the two data sets in a model-independent way and show that they can be reconciled if one avoids any bias on the neutrino spectrum stemming from theoretical conjecture. We reconstruct the neutrino spectrum from SN 1987A directly from the data through nonparametric inferential statistical methods and present predictions for the diffuse supernova neutrino background based on SN 1987A data. We show that this prediction cannot be too small (especially in the 10-18 MeV range), since the majority of the detected events from SN 1987A were above 18 MeV (including 6 events above 35 MeV), suggesting an imminent detection in operational and planned detectors

  7. Experimental Study of the Sb-Sn-Zn Alloy System

    Czech Academy of Sciences Publication Activity Database

    Zobač, O.; Sopoušek, J.; Buršík, Jiří; Zemanová, Adéla; Roupcová, Pavla

    2014-01-01

    Roč. 45, č. 3 (2014), s. 1181-1188 ISSN 1073-5623 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Sb-Sn-Zn system * thermal analysis * CALPHAD method Subject RIV: BJ - Thermodynamics Impact factor: 1.730, year: 2014

  8. Properties of idealized designs of NB3SN composites

    International Nuclear Information System (INIS)

    Smathers, D.B.; Larbalestier, D.C.; Lee, P.J.; Marken, K.R.; McDonald, W.K.; O'Larey, P.M.

    1985-01-01

    A series of seven idealized bronze-Nb 3 Sn composites were manufactured by the MJR process with varying matrix to filament ratios and pure Nb and Nb 0.8 wt.% Ti cores. The central core of each composite was sealed by a diffusion barrier which results in each filament having an identical source of tin. Initial evaluations of the composites from critical current and transmission electron microscopy measurements are presented and their properties compared to standard MJR composites. The Nb 3 Sn current density does not appear to be a strong function of bronze to Nb ratio over the range 2.4 to 3.2:1. The standard MJR composites have higher critical current densities than the idealized composites. It is proposed that the major reason for the increased current density of the normal MJR conductors is the intrinsically higher quality of the filaments close to the central tin core. It is postulated that the high Sn content of the bronze surrounding these filaments leads to an intrinsically higher Nb 3 Sn filament current density

  9. Quality control for 12 batch of DTPA-Sn

    International Nuclear Information System (INIS)

    Isaac, M.; Gamboa, R.; Leyva, R.; Hernandez, I.; Turino, D.

    1994-01-01

    The quality control is carry out at 12 batch of DTPA-Sn for labeling with 99 m Tc. The instrumental methods of analysis and control charts were discussed in order to find a warranty time for the product. (author). 2 refs, 3 figs, 1 tab

  10. Electrodeposited Cu2ZnSnS4 thin films

    CSIR Research Space (South Africa)

    Valdes, M

    2014-05-01

    Full Text Available Cu(sub2)ZnSnS(sub4)(CZTS) thin films have been prepared using Electrochemical Atomic Layer Deposition (EC-ALD)and also by one-step conventional constant potential electrodeposition. Optimal deposition conditionswere investigated using cyclic...

  11. Thermochemistry of liquid Ni–Sb–Sn alloys

    Czech Academy of Sciences Publication Activity Database

    Mishra, R.; Kroupa, Aleš; Terzieff, P.; Ipser, H.

    2012-01-01

    Roč. 536, MAY (2012), s. 68-73 ISSN 0040-6031 R&D Projects: GA MŠk(CZ) OC08053 Institutional support: RVO:68081723 Keywords : Ni-Sb-Sn alloys * thermochemistry * vapor pressure measurements Subject RIV: BJ - Thermodynamics Impact factor: 1.989, year: 2012

  12. Nonlinear optical properties of Sn+ ion-implanted silica glass

    International Nuclear Information System (INIS)

    Takeda, Y.; Hioki, T.; Motohiro, T.; Noda, S.; Kurauchi, T.

    1994-01-01

    The absolute value of the third-order nonlinear optical susceptibility, vertical stroke χ (3) vertical stroke , of Sn + ion-implanted silica glass was found to be similar 10 -6 esu. This value is as large as those reported for semiconductor-doped glasses. Silica glass substrates were implanted with Sn + ions at an acceleration energy of 400 keV to a dose of 2x10 17 ions/cm 2 at room temperature. Metallic Sn microcrystallites of 4-20 nm in diameter were found to be embedded in the silica glass matrix. The average volume fraction of the Sn microcrystallites was evaluated to be 28%. vertical stroke χ (3) vertical stroke and the imaginary part of the dielectric function, Im ε, had peaks at the same wavelength of 500 nm owing to surface plasmon resonance. The peak width of vertical stroke χ (3) vertical stroke was nearly half of that of Im ε, which can be explained by an effective medium theory. ((orig.))

  13. Strain sensitivity of band gaps of Sn-containing semiconductors

    DEFF Research Database (Denmark)

    Li, Hong; Castelli, Ivano Eligio; Thygesen, Kristian Sommer

    2015-01-01

    Tuning of band gaps of semiconductors is a way to optimize materials for applications within photovoltaics or as photocatalysts. One way to achieve this is through applying strain to the materials. We investigate the effect of strain on a range of Sn-containing semiconductors using density...

  14. Coulomb excitation of $^{110}$Sn using REX-ISOLDE

    CERN Document Server

    Ekström, A; Hurst, A; Fahlander, C; Banu, A; Butler, P; Eberth, J; Górska, M; Habs, D; Huyse, M; Kester, O; Niedermayer, O; Nilsson, T; Pantea, M; Scheit, H; Schwalm, D; Sletten, G; Ushasi, D P; Van Duppen, P; Warr, N; Weisshaar, D

    2006-01-01

    In this paper, we report the preliminary result from the first Coulomb excitation experiment at REX-ISOLDE (Habs et al 1998 Nucl. Instrum. Methods B 139 128) using neutron-deficient Sn-beams. The motivation of the experiment is to deduce the reduced transition probability, B(E2 ; 2$^+\\rightarrow$ 0$^+$) , for the sequence of neutron deficient, unstable, even-even Sn-isotopes from using a radioactive beam opens up a new path to study the lifetime of the first excited 2$^+$ state in these isotopes. The de-excitation path following fusion-evaporation reactions will for the even-even Sn isotopes pass via an isomeric 6$^+$ state, located at higher energy, which thus hampers measurements of the lifetime of the first excited state using, e.g., recoil-distance methods. For this reason the reduced transition probability of the first excited 2$^+$ state has remained unknown in this chain of isotopes although the B(E2) value of the stable isotope $^{112}$Sn was measured approximately 30 years ago (see, e.g., Stelson et...

  15. Sn nanothreads in GaAs: experiment and simulation

    Science.gov (United States)

    Semenikhin, I.; Vyurkov, V.; Bugaev, A.; Khabibullin, R.; Ponomarev, D.; Yachmenev, A.; Maltsev, P.; Ryzhii, M.; Otsuji, T.; Ryzhii, V.

    2016-12-01

    The gated GaAs structures like the field-effect transistor with the array of the Sn nanothreads was fabricated via delta-doping of vicinal GaAs surface by Sn atoms with a subsequent regrowth. That results in the formation of the chains of Sn atoms at the terrace edges. Two device models were developed. The quantum model accounts for the quantization of the electron energy spectrum in the self-consistent two-dimensional electric potential, herewith the electron density distribution in nanothread arrays for different gate voltages is calculated. The classical model ignores the quantization and electrons are distributed in space according to 3D density of states and Fermi-Dirac statistics. It turned out that qualitatively both models demonstrate similar behavior, nevertheless, the classical one is in better quantitative agreement with experimental data. Plausibly, the quantization could be ignored because Sn atoms are randomly placed along the thread axis. The terahertz hot-electron bolometers (HEBs) could be based on the structure under consideration.

  16. NdRhSn: A ferromagnet with an antiferromagnetic precursor

    Czech Academy of Sciences Publication Activity Database

    Mihalik, M.; Prokleška, J.; Kamarád, Jiří; Prokeš, K.; Isnard, O.; McIntyre, G. J.; Dönni, A.; Yoshii, S.; Kitazawa, H.; Sechovský, V.; de Boer, F.R.

    2011-01-01

    Roč. 83, č. 10 (2011), "104403-1"-"104403-10" ISSN 1098-0121 R&D Projects: GA ČR GA202/09/1027 Institutional research plan: CEZ:AV0Z10100521 Keywords : NdRhSn * ferromagnet * antiferromagnetic precursor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

  17. Thermal x-rays from SN 1987A

    International Nuclear Information System (INIS)

    Nomoto, K.; Shigeyama, T.; Hayakawa, S.; Itoh, H.; Masai, K.

    1988-01-01

    The authors discuss how the x-ray spectrum of SN 1987A observed with the Ginga satellite may be explained by the ejecta-circumstellar matter collision model at photon energies below 15 keV. The harder x-rays may be ascribed to Compton degradation of the gamma-rays from 56 Co

  18. Physics, SN1987A, and the next nearby supernova

    International Nuclear Information System (INIS)

    Burrows, A.

    1989-01-01

    The scientific community has extracted quite a bit of information from SN1987A, some of it enduring. I will summarize what I believe we learned, what we did not learn, and what we can learn about supernovae, neutrinos, and particle physics when the next galactic supernova explodes onto the news

  19. Nb3Sn accelerator magnet development around the world

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Lamm

    2003-06-23

    During the past 30 years superconducting magnet systems have enabled accelerators to achieve energies and luminosities that would have been impractical if not impossible with resistive magnets. By far, NbTi has been the preferred conductor for this application because of its ductility and insensitivity of Jc to mechanical strain. This is despite the fact that Nb{sub 3}Sn has a more favorable Jc vs. B dependence and can operate at much higher temperatures. Unfortunately, NbTi conductor is reaching the limit of it usefulness for high field applications. Despite incremental increases in Jc and operation at superfluid temperatures, magnets are limited to approximately a 10 T field. Improvements in conductor performance combined with future requirements for accelerator magnets to have bore fields greater than 10 T or operate in areas of large beam-induced heat loads now make Nb{sub 3}Sn look attractive. Thus, laboratories in several countries are actively engaged in programs to develop Nb{sub 3}Sn accelerator magnets for future accelerator applications. A summary of this important research activity is presented along with a brief history of Nb{sub 3}Sn accelerator magnet development and a discussion of requirements for future accelerator magnets.

  20. The European Nb3Sn advanced strand development programme

    International Nuclear Information System (INIS)

    Vostner, A.; Salpietro, E.

    2005-01-01

    Strands relevant for fusion with high critical current densities and moderate hysteresis losses were developed and already produced on industrial scale. Based on these achievements EFDA-CSU Garching has launched a Nb 3 Sn strand development and procurement action inside Europe in order to assess the current status of the Nb 3 Sn strand production capability. All six addressed companies have replied positively to the strand R and D programme which includes the three major Nb 3 Sn production techniques namely the bronze, internal-tin and powder-in-tube (PIT) route. According to the strand requirements for the ITER TF conductor a critical current density of 800 A/mm 2 (at 12 T, 4.2 K and 10 μV/m) and overall strand hysteresis losses below 500 kJ/m 3 have been specified as the minimum guaranteed strand performance. The second major objective of this programme is to motivate the strand manufacturers to develop and design high performance Nb 3 Sn strands optimised for the ITER conductor. For this purpose, a target critical current density of 1100 A/mm 2 has been added to the specification. This paper describes the strategy behind the strand development programme, the actual status of the strand production as well as first preliminary results obtained from the strand suppliers

  1. Hydrogen peroxide route to Sn-doped titania photocatalysts

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Matys Grygar, Tomáš; Henych, Jiří; Kormunda, M.

    2012-01-01

    Roč. 6, č. 1 (2012), s. 113 ISSN 1752-153X Institutional support: RVO:61388980 Keywords : photocatalysis * Sn doping * TiO2 * Vis light * Wet synthesis Subject RIV: CA - Inorganic Chemistry Impact factor: 1.312, year: 2012

  2. THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED

    International Nuclear Information System (INIS)

    Folatelli, Gastón; Bersten, Melina C.; Benvenuto, Omar G.; Kuncarayakti, Hanindyo; Maeda, Keiichi; Nomoto, Ken’ichi

    2015-01-01

    Hubble Space Telescope observations of the site of the supernova (SN) SN 2008ax obtained in 2011 and 2013 reveal that the possible progenitor object detected in pre-explosion images was in fact multiple. Four point sources are resolved in the new, higher-resolution images. We identify one of the sources with the fading SN. The other three objects are consistent with single supergiant stars. We conclude that their light contaminated the previously identified progenitor candidate. After subtraction of these stars, the progenitor appears to be significantly fainter and bluer than previously measured. Post-explosion photometry at the SN location indicates that the progenitor object has disappeared. If single, the progenitor is compatible with a supergiant star of B to mid-A spectral type, while a Wolf–Rayet (W-R) star would be too luminous in the ultraviolet to account for the observations. Moreover, our hydrodynamical modeling shows that the pre-explosion mass was 4–5 M ⊙ and the radius was 30–50 R ⊙ , which is incompatible with a W-R progenitor. We present a possible interacting binary progenitor computed with our evolutionary models that reproduces all the observational evidence. A companion star as luminous as an O9–B0 main-sequence star may have remained after the explosion

  3. Superconducting Nb{sub 3}Sn intermetallics made by electrochemical reduction of Nb{sub 2}O{sub 5}-SnO{sub 2} oxides

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, B A; Fray, D J; Yan, X-Y; Chen, G

    2003-05-01

    The article is focused on low temperature superconducting Nb{sub 3}Sn material manufactured by novel electrodeoxidizing method developed in Cambridge whereby the range of alloys and intermetallics are produced cheaply making potential superconducting wires more cost effective. The process of direct electrochemical reduction of Nb{sub 2}O{sub 5}-SnO{sub 2} mixtures and in situ formation of the Nb{sub 3}Sn is discussed in details.

  4. [Hyp-Au-Sn9(Hyp)3-Au-Sn9(Hyp)3-Au-Hyp]-: the longest intermetalloid chain compound of tin.

    Science.gov (United States)

    Binder, Mareike; Schrenk, Claudio; Block, Theresa; Pöttgen, Rainer; Schnepf, Andreas

    2017-10-12

    The reaction of the metalloid tin cluster [Sn 10 (Hyp) 4 ] 2- with (Ph 3 P)Au-SHyp (Hyp = Si(SiMe 3 ) 3 ) gave an intermetalloid cluster [Au 3 Sn 18 (Hyp) 8 ] - 1, which is the longest intermetalloid chain compound of tin to date. 1 shows a structural resemblance to binary AuSn phases, which is expected for intermetalloid clusters.

  5. Cytoplasmic assembly of snRNP particles from stored proteins and newly transcribed snRNA's in L929 mouse fibroblasts

    International Nuclear Information System (INIS)

    Sauterer, R.A.; Feeney, R.J.; Zieve, G.W.

    1988-01-01

    Newly synthesized snRNAs appear transiently in the cytoplasm where they assemble into ribonucleoprotein particles, the snRNP particles, before returning permanently to the interphase nucleus. In this report, bona fide cytoplasmic fractions, prepared by cell enucleation, are used for a quantitative analysis of snRNP assembly in growing mouse fibroblasts. The half-lives and abundances of the snRNP precursors in the cytoplasm and the rates of snRNP assembly are calculated in L929 cells. With the exception of U6, the major snRNAs are stable RNA species; U1 is almost totally stable while U2 has a half-life of about two cell cycles. In contrast, the majority of newly synthesized U6 decays with a half-life of about 15 h. The relative abundances of the newly synthesized snRNA species U1, U2, U3, U4 and U6 in the cytoplasm are determined by Northern hybridization using cloned probes and are approximately 2% of their nuclear abundance. The half-lives of the two major snRNA precursors in the cytoplasm (U1 and U2) are approximately 20 min as determined by labeling to steady state. The relative abundance of the snRNP B protein in the cytoplasm is determined by Western blotting with the Sm class of autoantibodies and is approximately 25% of the nuclear abundance. Kinetic studies, using the Sm antiserum to immunoprecipitate the methionine-labeled snRNP proteins, suggest that the B protein has a half-life of 90 to 120 min in the cytoplasm. These data are discussed and suggest that there is a large pool of more stable snRNP proteins in the cytoplasm available for assembly with the less abundant but more rapidly turning-over snRNAs

  6. Superconductivity, carrier concentration, and the ionic model of Sn/sub 4/P/sub 3/ and Sn/sub 4/As/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Van Maaren, M H

    1969-06-01

    Superconductivity is reported for Sn/sub 4/P/sub 2.65/ at T/sub c/ 1.2/sup 0/K. Hall constant and reflectivity measurements indicate a mixed type of conduction for Sn/sub 4/P/sub 2.65/ and Sn/sub 3.80/ As/sub 3/. The ionic model of Geller and Hull is not applicable.

  7. Crystal Structure, Optical, and Electrical Properties of SnSe and SnS Semiconductor Thin Films Prepared by Vacuum Evaporation Techniques for Solar Cell Applications

    Science.gov (United States)

    Ariswan; Sutrisno, H.; Prasetyawati, R.

    2017-05-01

    Thin films of SnSe and SnS semiconductors had been prepared by vacuum evaporation techniques. All prepared samples were characterized on their structure, optical, and electrical properties in order to know their application in technology. The crystal structure of SnSe and SnS was determined by X-Ray Diffraction (XRD) instrument. The morphology and chemical composition were obtained by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive of X-Ray Analysis (EDAX). The optical property such as band gap was determined by DR-UV-Vis (Diffuse Reflectance-Ultra Violet-Visible) spectroscopy, while the electrical properties were determined by measuring the conductivity by four probes method. The characterization results indicated that both SnSe and SnS thin films were polycrystalline. SnSe crystallized in an orthorhombic crystal system with the lattice parameters of a = 11.47 Å, b = 4.152 Å and c = 4.439 Å, while SnS had an orthorhombic crystal system with lattice parameters of a = 4.317 Å, b = 11.647 Å and c = 3.981 Å. Band gaps (Eg) of SnSe and SnS were 1.63 eV and 1.35 eV, respectively. Chemical compositions of both thin films were non-stoichiometric. Molar ratio of Sn : S was close to ideal which was 1 : 0.96, while molar ratio of Sn : S was 1 : 0.84. The surface morphology described the arrangement of the grains on the surface of the thin film with sizes ranging from 0.2 to 0.5 microns. Color similarity on the surface of the SEM images proved a homogenous thin layer.

  8. Synthesis and fundamental properties of stable Ph(3)SnSiH(3) and Ph(3)SnGeH(3) hydrides: model compounds for the design of Si-Ge-Sn photonic alloys.

    Science.gov (United States)

    Tice, Jesse B; Chizmeshya, Andrew V G; Groy, Thomas L; Kouvetakis, John

    2009-07-06

    The compounds Ph(3)SnSiH(3) and Ph(3)SnGeH(3) (Ph = C(6)H(5)) have been synthesized as colorless solids containing Sn-MH(3) (M = Si, Ge) moieties that are stable in air despite the presence of multiple and highly reactive Si-H and Ge-H bonds. These molecules are of interest since they represent potential model compounds for the design of new classes of IR semiconductors in the Si-Ge-Sn system. Their unexpected stability and high solubility also makes them a safe, convenient, and potentially useful delivery source of -SiH(3) and -GeH(3) ligands in molecular synthesis. The structure and composition of both compounds has been determined by chemical analysis and a range of spectroscopic methods including multinuclear NMR. Single crystal X-ray structures were determined and indicated that both compounds condense in a Z = 2 triclinic (P1) space group with lattice parameters (a = 9.7754(4) A, b = 9.8008(4) A, c = 10.4093(5) A, alpha = 73.35(10)(o), beta = 65.39(10)(o), gamma = 73.18(10)(o)) for Ph(3)SnSiH(3) and (a = 9.7927(2) A, b = 9.8005(2) A, c = 10.4224(2) A, alpha = 74.01(3)(o), beta = 65.48(3)(o), gamma = 73.43(3)(o)) for Ph(3)SnGeH(3). First principles density functional theory simulations are used to corroborate the molecular structures of Ph(3)SnSiH(3) and Ph(3)SnGeH(3), gain valuable insight into the relative stability of the two compounds, and provide correlations between the Si-Sn and Ge-Sn bonds in the molecules and those in tetrahedral Si-Ge-Sn solids.

  9. A15 Nb-Sn tunnel junction fabrication and properties

    International Nuclear Information System (INIS)

    Rudman, D.A.; Hellman, F.; Hammond, R.H.; Beasley, M.R.

    1984-01-01

    We have investigated the deposition conditions necessary to produce optimized films of A15 Nb-Sn (19--26 at. % Sn) by electron-beam codeposition. Reliable high-quality superconducting tunnel junctions can be made on this material by using an oxidized-amorphous silicon overlayer as the tunneling barrier and lead as the counter-electrode. These junctions have been used both as a tool for materials diagnosis and as a probe of the superconducting properties (critical temperature and gap) of the films. Careful control of the substrate temperature during the growth of the films has proved critical to obtain homogeneous samples. When the substrate temperature is properly stabilized, stoichiometric Nb 3 Sn is found to be relatively insensitive to the deposition temperature and conditions. In contrast, the properties of the off-stoichiometry (Sn-poor) material depend strongly on the deposition temperature. For this Sn-poor material the ratio 2Δ/kT/sub c/ at a given composition increases with increasing deposition temperature. This change appears to be due to an increase in the gap at the surface of the material (as measured by tunneling) relative to the critical temperature of the bulk. All the tunnel junctions exhibit some persistent nonidealities in their current-voltage characteristics that are qualitatively insensitive to composition or deposition conditions. In particular, the junctions show excess conduction below the sum of the energy gaps (with onset at the counter-electrode gap) and a broadened current rise at the sum gap. The detailed origins of these problems are not yet understood

  10. Mössbauer and heat capacity studies of ErZnSn2

    Directory of Open Access Journals (Sweden)

    Łątka Kazimierz

    2017-06-01

    Full Text Available Heat capacity results obtained for the intermetallic compound ErZnSn2 were re-analysed to also consider, apart from the classical Debye model, the anharmonicity of the crystal lattice and the proper set of Einstein modes. The 119mSn Mössbauer technique was applied to derive the hyperfine interaction parameters characteristic of the two inequivalent crystallographic Sn sites in the compound studied. Quadrupole interaction constants, as measured by 119mSn Mössbauer spectroscopy, allowed for estimations of Vzz components of the electric field gradient tensor that exist at both Sn sites in the discussed compound.

  11. Defect interactions in Sn1−xGex random alloys

    KAUST Repository

    Chroneos, Alexander; Bracht, H.; Grimes, R. W.; Jiang, C.; Schwingenschlö gl, Udo

    2009-01-01

    Sn1−xGex alloys are candidates for buffer layers to match the lattices of III-V or II-VI compounds with Si or Ge for microelectronic or optoelectronic applications. In the present work electronic structure calculations are used to study relative energies of clusters formed between Sn atoms and lattice vacancies in Ge that relate to alloys of low Sn content. We also establish that the special quasirandom structure approach correctly describes the random alloy nature of Sn1−xGex with higher Sn content. In particular, the calculated deviations of the lattice parameters from Vegard’s Law are consistent with experimental results.

  12. Defect interactions in Sn1−xGex random alloys

    KAUST Repository

    Chroneos, Alexander

    2009-06-23

    Sn1−xGex alloys are candidates for buffer layers to match the lattices of III-V or II-VI compounds with Si or Ge for microelectronic or optoelectronic applications. In the present work electronic structure calculations are used to study relative energies of clusters formed between Sn atoms and lattice vacancies in Ge that relate to alloys of low Sn content. We also establish that the special quasirandom structure approach correctly describes the random alloy nature of Sn1−xGex with higher Sn content. In particular, the calculated deviations of the lattice parameters from Vegard’s Law are consistent with experimental results.

  13. Synthesis mechanism of heterovalent Sn2O3 nanosheets in oxidation annealing process

    International Nuclear Information System (INIS)

    Zhao Jun-Hua; Wu Guo-Qiang; Yang Xu-Feng; Tan Rui-Qin; Yang Ye; Xu Wei; Li Jia; Shen Wen-Feng; Song Wei-Jie

    2015-01-01

    Heterovalent Sn 2 O 3 nanosheets were fabricated via an oxidation annealing process and the formation mechanism was investigated. The temperature required to complete the phase transformation from Sn 3 O 4 to Sn 2 O 3 was considered. Two contrasting experiments showed that both oxygen and heating were not necessary conditions for the phase transition. Sn 2 O 3 was formed under an argon protective atmosphere by annealing and could also be obtained at room temperature by exposing Sn 3 O 4 in atmosphere or dispersing in ethanol. The synthesis mechanism was proposed and discussed. This fundamental research is important for the technological applications of intermediate tin oxide materials. (paper)

  14. Preparation of SnO2 Nanoparticles by Two Different Wet Chemistry Methods

    International Nuclear Information System (INIS)

    Ridha, N.J.; Akrajas Ali Umar; Muhammad Yahya; Muhammad Mat Salleh; Mohamad Hafizuddin Jumali

    2011-01-01

    The objective of this project is to prepare SnO 2 nanoparticles by two different wet chemistry methods namely sol gel and direct growth methods. The XRD results indicated that both samples are single phase SnO 2 . The FE-SEM micrographs displayed that SnO 2 nanoparticles prepared in first method exhibited a round shape with particle size around 15 nm while the second method produced SnO 2 nano rod with length and width of 570 nm and 55 nm respectively. Energy gap values for SnO 2 nanospheres and nano rods were 4.38 and 4.34 eV respectively. (author)

  15. The development of 126Sn separation procedure by means of TBP resin

    International Nuclear Information System (INIS)

    Andris, Boris; Bena, Jozef

    2016-01-01

    Separation possibilities of 126 Sn with a new extraction-chromatographic material TBP Resin were studied. Suitable conditions for tin separation were determined in hydrochloric acid medium. 126 Sn was concentrated on TBP resin from 6 mol L -1 HCl and was eluted with 0.1 mol L -1 HCl. A purification step to remove 137 Cs with AMP-PAN column was necessary to obtain sufficiently purified samples which were directly measured with gamma spectrometry for 126 Sn activity. Separation of 126 Sn from a raw sludge sample was done according to proposed procedure, 126 Sn was detected and its activity was determined. (author)

  16. Effect of solvent on the synthesis of SnO_2 nanoparticles

    International Nuclear Information System (INIS)

    Kumar, Virender; Singh, Karamjit; Singh, Kulwinder; Kumar, Akshay; Kumari, Sudesh; Thakur, Anup

    2016-01-01

    Tin oxide (SnO_2) nanoparticles have been synthesized by co-precipitation method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD) and Ultraviolet-Visible spectroscopy (UV-VIS). XRD analysis confirmed the formation of single phase of SnO_2 nanoparticles. It has been found that solvents played important role in controlling the crystallite size of SnO_2 nanoparticles. The XRD analysis showed well crystallized tetragonal SnO_2 nanoparticles. The crystallite size of SnO_2 nanoparticles varies with the solvent. Tauc plot showed that optical band gap was also tailored by controlling the solvent during synthesis.

  17. Design and assembly of ternary Pt/Re/SnO2 NPs by controlling the zeta potential of individual Pt, Re, and SnO2 NPs

    Science.gov (United States)

    Drzymała, Elżbieta; Gruzeł, Grzegorz; Pajor-Świerzy, Anna; Depciuch, Joanna; Socha, Robert; Kowal, Andrzej; Warszyński, Piotr; Parlinska-Wojtan, Magdalena

    2018-05-01

    In this study Pt, Re, and SnO2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO2 and Re/SnO2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO2 and Re/SnO2 NP, as well as ternary Pt/Re/SnO2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations. [Figure not available: see fulltext.

  18. Unusually large chemical potential shift in a degenerate semiconductor: Angle-resolved photoemission study of SnSe and Na-doped SnSe

    Science.gov (United States)

    Maeda, M.; Yamamoto, K.; Mizokawa, T.; Saini, N. L.; Arita, M.; Namatame, H.; Taniguchi, M.; Tan, G.; Zhao, L. D.; Kanatzidis, M. G.

    2018-03-01

    We have studied the electronic structure of SnSe and Na-doped SnSe by means of angle-resolved photoemission spectroscopy. The valence-band top reaches the Fermi level by the Na doping, indicating that Na-doped SnSe can be viewed as a degenerate semiconductor. However, in the Na-doped system, the chemical potential shift with temperature is unexpectedly large and is apparently inconsistent with the degenerate semiconductor picture. The large chemical potential shift and anomalous spectral shape are key ingredients for an understanding of the novel metallic state with the large thermoelectric performance in Na-doped SnSe.

  19. Studies of the labelling of human serum albumin with 99mTc using Sn(II) tartrate and Sn(II)Cl2 as reducing agents

    International Nuclear Information System (INIS)

    El-Kolaly, M.T.; El-Asrag, H.A.; El-Wetery, A.S.; El-Mohty, A.A.

    1990-01-01

    A comparative study has been carried out on the effect of Sn(II) tartrate and Sn(II)Cl 2 on the labelling efficiency and tissue distribution of 99m Tc-human serum albumin. The effect of reductant content, reaction time (incubation time), albumin content, pH, and ascorbic acid on the efficiency of labelling and the tissue distribution of the labelled albumin has been investigated. The percentage of labelling was determined by paper and thin layer radiochromatography. Ascorbic acid shows no effect on either labelling efficiency or tissue distribution of 99m Tc-HSA prepared by Sn(II) tartrate or Sn(II)Cl 2 . (author)

  20. SnO2Nanowire Arrays and Electrical Properties Synthesized by Fast Heating a Mixture of SnO2and CNTs Waste Soot

    Directory of Open Access Journals (Sweden)

    Zhou Zhi-Hua

    2009-01-01

    Full Text Available Abstract SnO2nanowire arrays were synthesized by fast heating a mixture of SnO2and the carbon nanotubes waste soot by high-frequency induction heating. The resultant SnO2nanowires possess diameters from 50 to 100 nm and lengths up to tens of mircrometers. The field-effect transistors based on single SnO2nanowire exhibit that as-synthesized nanowires have better transistor performance in terms of transconductance and on/off ratio. This work demonstrates a simple technique to the growth of nanomaterials for application in future nanoelectronic devices.