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.

NMR study of distinct phase transitional behaviors in (CnH2n+1NH3)2SnCl6

International Nuclear Information System (INIS)

Lee, K. W.; Lee, C. E.; Choi, J. Y.; Kim, J.

2005-01-01

Phase transitions in bis-(n-C n H 2n+1 NH 3 ) 2 SnCl 6 , where the hydrocarbon part is analogous to lipid membrane, were investigated by means of 200-MHz 1 H nuclear magnetic resonance. As a result, critical fluctuations and molecular dynamics associated with the phase transitions, an order-disorder and a conformational phase transition, were distinguished in a wide temperature range. The critical dynamics, observed in the long-chain compounds but not in the short-chain compounds by laboratory frame spin-lattice relaxation measurements, is discussed in view of the chain length dependence of molecular dynamics.

Influence of Sn doping in BaSnxTi1-xO3 ceramics on microstructural and dielectric properties

Science.gov (United States)

Ansari, Mohd. Azaj; Sreenivas, K.

2018-05-01

BaSnxTi1-x O3 solid solutions with varying Sn content (x = 0.00, 0.05, 0.15, 0.25) prepared by solid state reaction method have been studied for their structural and dielectric properties. X-ray diffraction and Raman spectroscopic analysis show composition induced modifications in the crystallographic structure, and with increasing Sn content the structure changes from tetragonal to cubic structure. The tetragonal distortion decreases with increasing Sn, and the structure becomes purely cubic for x =0.25. Changes in the structure are reflected in the temperature dependent dielectric properties. For increasing Sn content the peak dielectric constant is found to increase and the phase transition temperature (Tc) decreases to lower temperature. The purely cubic structure with x=0.25 shows a diffused phased transition.

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.)

Two transitional type Ia supernovae located in the Fornax cluster member NGC 1404: SN 2007on and SN 2011iv

Science.gov (United States)

Gall, C.; Stritzinger, M. D.; Ashall, C.; Baron, E.; Burns, C. R.; Hoeflich, P.; Hsiao, E. Y.; Mazzali, P. A.; Phillips, M. M.; Filippenko, A. V.; Anderson, J. P.; Benetti, S.; Brown, P. J.; Campillay, A.; Challis, P.; Contreras, C.; Elias de la Rosa, N.; Folatelli, G.; Foley, R. J.; Fraser, M.; Holmbo, S.; Marion, G. H.; Morrell, N.; Pan, Y.-C.; Pignata, G.; Suntzeff, N. B.; Taddia, F.; Robledo, S. Torres; Valenti, S.

2018-03-01

We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by Δm15 (B) decline-rate values of 1.96 mag and 1.77 mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by 0.60 mag and 0.35 mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by 14% and 9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B - V colour is 0.12 mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, 56Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity-width relation, while the central density is an important second-order parameter. Within this context, the differences in the B - V colour evolution along the Lira regime suggest that the progenitor of SN 2011iv had a higher central density than SN 2007on. The photometry tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A58

Transitions in creep mechanisms and creep anisotropy in Zr-1Nb-1Sn-0.2Fe sheet

International Nuclear Information System (INIS)

Murty, K.L.; Ravi, J.; Wiratmo

1995-01-01

The creep characteristics of a Zr-1Nb-1Sn-0.2Fe alloy sheet were investigated at temperatures from 773 to 923K and at stresses ranging from 9 to 150MPa along both the rolling and transverse directions. Transitions in creep mechansims are noted, with diffusional viscous creep at low stresses, viscous-glide-controlled microcreep in the intermediate stress regime and the climb of edge dislocations at high stresses. The creep anisotropy decreases with a decrease in the stress exponent and the creep rates differ by only 30% in the viscous creep regime, while an order-of-magnitude difference is noted at high stresses. The solute-strengthening effect of Nb addition is evident in the stress regime where appropriate data are available. These transitions in creep mechansims clearly reveal the dangers in blind extrapolation of short-term high stress data to low stresses and long times relevant to in-reactor conditions. The creep behavior of these materials is similar to that noted in Class I alloys, while the transitions in deformation mechanisms in Zircaloy-4 resemble those found in pure metals or Class II alloys with no viscous glide mechanism. ((orig.))

Phase diagram and structural evolution of tin/indium (Sn/In) nanosolder particles: from a non-equilibrium state to an equilibrium state.

Science.gov (United States)

Shu, Yang; Ando, Teiichi; Yin, Qiyue; Zhou, Guangwen; Gu, Zhiyong

2017-08-31

A binary system of tin/indium (Sn/In) in the form of nanoparticles was investigated for phase transitions and structural evolution at different temperatures and compositions. The Sn/In nanosolder particles in the composition range of 24-72 wt% In were synthesized by a surfactant-assisted chemical reduction method under ambient conditions. The morphology and microstructure of the as-synthesized nanoparticles were analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD). HRTEM and SAED identified InSn 4 and In, with some Sn being detected by XRD, but no In 3 Sn was observed. The differential scanning calorimetry (DSC) thermographs of the as-synthesized nanoparticles exhibited an endothermic peak at around 116 °C, which is indicative of the metastable eutectic melting of InSn 4 and In. When the nanosolders were subjected to heat treatment at 50-225 °C, the equilibrium phase In 3 Sn appeared while Sn disappeared. The equilibrium state was effectively attained at 225 °C. A Tammann plot of the DSC data of the as-synthesized nanoparticles indicated that the metastable eutectic composition is about 62% In, while that of the DSC data of the 225 °C heat-treated nanoparticles yielded a eutectic composition of 54% In, which confirmed the attainment of the equilibrium state at 225 °C. The phase boundaries estimated from the DSC data of heat-treated Sn/In nanosolder particles matched well with those in the established Sn-In equilibrium phase diagram. The phase transition behavior of Sn/In nanosolders leads to a new understanding of binary alloy particles at the nanoscale, and provides important information for their low temperature soldering processing and applications.

Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE

CERN Multimedia

Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S

2002-01-01

It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.

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.

Crystallization kinetics in Si-1 at%Sn during rapid solidification in undercooled melt

Science.gov (United States)

Kuribayashi, K.; Ozawa, S.; Nagayama, K.; Inatomi, Y.

2017-06-01

In order to elucidate the cause of the morphological transition of crystals growing in an undercooled melt of semiconducting materials, we carried out the containerless solidification of undoped Si and Si-1 at%Sn using a CO2 laser-equipped electromagnetic levitator (EML). The crystallization of these materials was successfully achieved under controlled undercooling. The relation between the shape of growing crystals and the degree of undercooling in Si-1 at%Sn was similar to that in undoped Si; that is, plate-like needle crystals were observed at low undercooling, whereas at medium and high undercooling the shape of growing crystals changed to massive dendrites. The grain-size of as-solidified samples of Si-1 at%Sn was remarkably small compared with that of undoped Si. The surface morphologies of samples solidified by dropping the melt onto a chill plate of mirror-polished silicon consisted of typical twin-related dendrites. On the other hand, samples that were dropped from the undercooled state consisted of twin-free dendrites. The nucleation rate of two-dimensional nuclei calculated on the basis of two mechanisms, which are the twin-plane re-entrant edge mechanism and the twin-free mechanism, suggested that the morphological transition to twin-free dendrites from twin-related dendrites occurs when the degree of undercooling becomes larger than the critical value. These results indicate that the cause of the morphological transition of Si growing in the undercooled melt is not the roughening transition of the crystal-melt interface but the transition of the nucleation kinetics to the twin-free mechanism from the twin-related mechanism.

{sup 119}Sn NMR investigations on superconducting Ca{sub 3}Ir{sub 4}Sn{sub 13}

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Rajib; Brueckner, Felix; Guenther, Marco; Klauss, Hans-Henning [IFP, TU Dresden (Germany); Petrovic, Cedomir; Wang, Kefeng [CMPMS, BNL, Upton, NY (United States); Luetkens, Hubertus; Biswas, Pabitra; Morenzoni, Elvezio; Amato, Alex [PSI, Villigen (Switzerland)

2014-07-01

Ca{sub 3}Ir{sub 4}Sn{sub 13} was found to exhibit superconducting transition with T{sub c} ∼ 7 K. It received considerable attention due to the possible coexistence of superconductivity and ferromagnetic spin fluctuation as well as the three-dimensional charge density wave (CDW) from the superlattice transition. While thermal, transport, and thermodynamic characterization of Ca{sub 3}Ir{sub 4}Sn{sub 13} single crystals suggest that it is a weakly correlated nodeless superconductor, recent μSR investigation reveals that the electron-phonon pairing interaction is in the strong-coupling limit. Here we present {sup 119}Sn NMR investigations on Ca{sub 3}Ir{sub 4}Sn{sub 13} polycrystalline samples and discuss the symmetry of the superconducting order parameter together with the normal state properties. Our preliminary results of spin-lattice relaxation rate (1/T{sub 1}) indicate that this is a BCS superconductor with weak-coupling limit.

SnTe field effect transistors and the anomalous electrical response of structural phase transition

International Nuclear Information System (INIS)

Li, Haitao; Zhu, Hao; Yuan, Hui; Li, Qiliang; You, Lin; Kopanski, Joseph J.; Richter, Curt A.; Zhao, Erhai

2014-01-01

SnTe is a conventional thermoelectric material and has been newly found to be a topological crystalline insulator. In this work, back-gate SnTe field-effect transistors have been fabricated and fully characterized. The devices exhibit n-type transistor behaviors with excellent current-voltage characteristics and large on/off ratio (>10 6 ). The device threshold voltage, conductance, mobility, and subthreshold swing have been studied and compared at different temperatures. It is found that the subthreshold swings as a function of temperature have an apparent response to the SnTe phase transition between cubic and rhombohedral structures at 110 K. The abnormal and rapid increase in subthreshold swing around the phase transition temperature may be due to the soft phonon/structure change which causes the large increase in SnTe dielectric constant. Such an interesting and remarkable electrical response to phase transition at different temperatures makes the small SnTe transistor attractive for various electronic devices.

Effect of the final-state interaction on the initial core-hole lifetime: the case of the 4s-hole lifetime of Sn metal

International Nuclear Information System (INIS)

Ohno, Masahide

2003-01-01

The first theoretical study of the effect of the final-state interaction on the initial core-hole lifetime is presented. The 4s-hole lifetime width of Sn metal is calculated by an ab-initio atomic many-body theory (Green's function method). When the final-state interaction in the 4p4d two-hole state, created by the 4s -1 -4p -1 4d -1 εf super Coster-Kronig (CK) transition of the initial 4s hole, is explicitly taken into account, the ab-initio atomic many-body calculation of the 4s-hole X-ray photoelectron spectroscopy (XPS) spectrum of Sn atom can provide excellent agreement with experiment in both the 4s-hole energy and the 4s-hole lifetime width. Otherwise, the many-body calculation underestimates considerably the 4s-hole lifetime width. The 4p4d two-hole state interacts strongly with the 4d triple-hole state by the 4p -1 4d -1 -4d -3 εf super CK transition. The interaction affects greatly the initial 4s-hole lifetime width

On possibility of superconductivity in SnSb: A first principle study

Energy Technology Data Exchange (ETDEWEB)

Dabhi, Shweta D. [Department of Physics, M. K. Bhavnagar University, Bhavnagar 364001 (India); Shrivastava, Deepika [Department of Physics, Barkatullah University, Bhopal 462026 (India); Jha, Prafulla K., E-mail: prafullaj@yahoo.com [Department of Physics, Faculty of Science, The M. S. University of Baroda, Vadodara 390002 (India); Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

2016-09-15

Highlights: • Superconducting property of SnSb is predicted by ab-initio calculations. • Electronic properties of SnSb in RS phase shows metallic behaviour similar to SnAs. • Phonon dispersion confirms the dynamical stability of SnSb in RS phase. • Superconducting transition temperature is 3.1 K, slightly lower than that of SnAs. • Calculated thermodynamic properties are also reported. - Abstract: The electronic, phonon structure and superconducting properties of tin antimonide (SnSb) in rock-salt (RS) structure are calculated using first-principles density functional theory. The electronic band structure and density of states show metallic behavior. The phonon frequencies are positive throughout the Brillouin zone in rock-salt structure indicating its stability in that phase. Superconductivity of SnSb in RS phase is discussed in detail by calculating phonon linewidths, Eliashberg spectral function, electron-phonon coupling constant and superconducting transition temperature. SnSb is found to have a slightly lower T{sub C} (3.1 K), as compared to SnAs.

Evidence for a second-order phase transition around 350 K in Ce3Rh4Sn13

Science.gov (United States)

Kuo, C. N.; Chen, W. T.; Tseng, C. W.; Hsu, C. J.; Huang, R. Y.; Chou, F. C.; Kuo, Y. K.; Lue, C. S.

2018-03-01

We report an observation of a phase transition in Ce3Rh4Sn13 with the transition temperature T*≃350 K by means of synchrotron x-ray powder diffraction, specific heat, electrical resistivity, Seebeck coefficient, thermal conductivity, as well as 119Sn nuclear magnetic resonance (NMR) measurements. The phase transition has been characterized by marked features near T* in all measured physical quantities. The lack of thermal hysteresis in the specific heat indicates a second-order phase transition in nature. From the NMR analysis, the change in the transferred hyperfine coupling constant for two tin sites has been resolved. The obtained result has been associated with the reduction in the averaged interatomic distance between Ce and Sn atoms, particularly for the Sn2 atoms. It indicates that the movement of the Sn2 atoms, which deforms the high-temperature structure, shortens the Ce-Sn2 bond length at low temperatures. We therefore provide a concise picture that the observed second-order phase transition at T* of Ce3Rh4Sn13 should be characterized by a structural modulation essentially due to lattice distortions arising from phonon instability.

Study of the β{sup -} decay of {sup 116m1}In: A new interpretation of low-lying 0{sup +} states in {sup 116}Sn

Energy Technology Data Exchange (ETDEWEB)

Pore, J.L.; Cross, D.S.; Andreoiu, C.; Ashley, R.; Chester, A.S.; Noakes, B.; Starosta, K.; Voss, P.J. [Simon Fraser University, Department of Chemistry, Burnaby BC (Canada); Ball, G.C.; Bender, P.C.; Garnsworthy, A.B.; Hackman, G.; Rajabali, M.M. [TRIUMF, Vancouver BC (Canada); Diaz Varela, A.; Demand, G.A.; Dunlop, R.; Garrett, P.E.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A.T.; Liblong, A.; Svensson, C.E. [University of Guelph, Department of Physics, Guelph ON (Canada); Kanungo, R. [Saint Mary' s University, Department of Astronomy and Physics, Halifax NS (Canada); Petrache, C.M. [Universite Paris-Saclay, CSNSM, CNRS-IN2P3, Orsay Cedex (France); Wang, Z.M. [Simon Fraser University, Department of Chemistry, Burnaby BC (Canada); TRIUMF, Vancouver BC (Canada); Wood, J.L. [Georgia Institute of Technology, School of Physics, Atlanta, GA (United States); Yates, S.W. [University of Kentucky, Departments of Chemistry and Physics and Astronomy, Lexington, KY (United States)

2017-02-15

The {sup 116}Sn nucleus contains a collective rotational band originating from proton π 2p-2h excitations across the proton Z = 50 shell gap. Even though this nucleus has been extensively investigated in the past, there was still missing information on the low-energy interband transitions connecting the intruder and normal structures. The low-lying structure of {sup 116}Sn was investigated through a high-statistics study of the β{sup -} decay of {sup 116m1}In with the 8π spectrometer and its ancillary detectors at TRIUMF. These measurements are critical in order to properly characterize the π 2p-2h rotational band. Weak γ-decay branches are observed utilizing γ-γ coincidence spectroscopy methods, leading to the first direct observation of the 85 keV 2{sub 2}{sup +} → 0{sub 3}{sup +} γ ray with a transition strength of B(E2) = 99.7(84) W.u. The analysis of these results strongly suggests that the 2027 keV 0{sub 3}{sup +} state should replace the previously assigned 1757 keV 0{sub 2}{sup +} state as the band-head of the π 2p-2h rotational band. (orig.)

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

The formation of α-phase SnS nanorods by PVP assisted polyol synthesis: Phase stability, micro structure, thermal stability and defects induced energy band transitions

Energy Technology Data Exchange (ETDEWEB)

Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com

2017-05-01

We report the formation of single phase of SnS nanostructure through PVP assisted polyol synthesis by varying the source concentration ratio (Sn:S) from 1:1M to 1:12M. The effect of PVP concentration and reaction medium towards the preparation of SnS nanostructure is systematically studied through confocal Raman spectrometer, X-ray diffraction, thermogravimetry analysis, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis–NIR absorption and fluorescence spectrophotometers. The surface morphology of SnS nanostructure changes from nanorods to spherical shape with increasing PVP concentration from 0.15M to 0.5M. Raman analysis corroborates that Raman active modes of different phases of Sn-S are highly active when Raman excitation energy is slightly greater than the energy band gap of the material. The presence of intrinsic defects and large number of grain boundaries resulted in an improved thermal stability of 20 °C during the phase transition of α-SnS. Band gap calculation from tauc plot showed the direct band gap of 1.5 eV which is attributed to the single phase of SnS, could directly meet the requirement of an absorber layer in thin film solar cells. Finally, we proposed an energy band diagram for as synthesized single phase SnS nanostructure based on the experimental results obtained from optical studies showing the energy transitions attributed to band edge transition and also due to the presence of intrinsic defects. - Highlights: • PVP stabilizes the orthorhombic (α) phase of SnS. • Optical band gap of P type SnS tuned by PVP for photovoltaic applications. • The formation of Sn rich SnS phase is investigated through XPS analysis. • Intrinsic defects enhance the thermal stability of α-SnS. • The feasibility of energy transition liable to point defects is discussed.

Crystal structure and phase transitions in perovskite-like C(NH2)3SnCl3

International Nuclear Information System (INIS)

Szafranski, Marek; Stahl, Kenny

2007-01-01

X-ray single-crystal diffraction, high-temperature powder diffraction and differential thermal analysis at ambient and high pressure have been employed to study the crystal structure and phase transitions of guanidinium trichlorostannate, C(NH 2 ) 3 SnCl 3 . At 295 K the crystal structure is orthorhombic, space group Pbca, Z=8, a=7.7506(2) A, b=12.0958(4) A and c=17.8049(6) A, solved from single-crystal data. It is perovskite-like with distorted corner-linked SnCl 6 octahedra and with ordered guanidinium cations in the distorted cuboctahedral voids. At 400 K the structure shows a first-order order-disorder phase transition. The space group is changed to Pnma with Z=4, a=12.1552(2) A, b=8.8590(2) A and c=8.0175(1) A, solved from powder diffraction data and showing disordering of the guanidinium cations. At 419 K, the structure shows yet another first-order order-disorder transformation with disordering of the SnCl 3 - part. The space group symmetry is maintained as Pnma, with a=12.1786(2) A, b=8.8642(2) A and c=8.0821(2) A. The thermodynamic parameters of these transitions and the p-T phase diagram have been determined and described. - Graphical abstract: The perovskite-like crystals of C(NH 2 ) 3 SnCl 3 undergo two successive first-order phase transitions at 400 and 419 K, both accompanied by an essential order-disorder contribution. The p-T phase diagram exhibits a singular point at 219 MPa and 443 K

Thermal properties and phase transition in the fluoride, (NH4)3SnF7

International Nuclear Information System (INIS)

Kartashev, A.V.; Gorev, M.V.; Bogdanov, E.V.; Flerov, I.N.; Laptash, N.M.

2016-01-01

Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH 4 ) 3 SnF 7 for a wide range of temperatures and pressures. Large entropy (δS 0 =22 J/mol K) and elastic deformation (δ(ΔV/V) 0 =0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS 0 =32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH 4 ) 3 TiF 7 , undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH 4 ) 3 SnF 7 , contrary to (NH 4 ) 3 TiF 7 , characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH 4 ) 3 SnF 7 was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH 4 ) 3 SnF 7 is associated with very large total entropy change of ΔS 0 =32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH 4 ) 3 TiF 7 undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH 4 ) 3 SnF 7 undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC p and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH 4 ) 3 SnF 7 . • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

Phase transition temperatures of Sn-Zn-Al system and their comparison with calculated phase diagrams

Czech Academy of Sciences Publication Activity Database

Smetana, B.; Zlá, S.; Kroupa, Aleš; Žaludová, M.; Drápala, J.; Burkovič, R.; Petlák, D.

2012-01-01

Roč. 110, č. 1 (2012), s. 369-378 ISSN 1388-6150 R&D Projects: GA MŠk(CZ) OC08053 Institutional support: RVO:68081723 Keywords : Sn-Zn-Al system * DTA * phase transition temperatures Subject RIV: BJ - Thermodynamics Impact factor: 1.982, year: 2012

The Transition of a Type IIL Supernova into a Supernova Remnant: Late-time Observations of SN 2013by

Energy Technology Data Exchange (ETDEWEB)

Black, C. S.; Fesen, R. A. [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Milisavljevic, D.; Patnaude, D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Margutti, R. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Parker, S. [Parkdale Observatory, 225 Warren Road, RDl Oxford, Canterbury 7495 (New Zealand)

2017-10-10

We present early-time Swift and Chandra X-ray data along with late-time optical and near-infrared observations of SN 2013by, a Type IIL supernova (SN) that occurred in the nearby spiral galaxy ESO 138−G10 ( D ∼ 14.8 Mpc). Optical and NIR photometry and spectroscopy follow the late-time evolution of the SN from days +89 to +457 post maximum brightness. The optical spectra and X-ray light curves are consistent with the picture of an SN having prolonged interaction with circumstellar material (CSM) that accelerates the transition from SN to supernova remnant (SNR). Specifically, we find SN 2013by’s H α profile exhibits significant broadening (∼10,000 km s{sup −1}) on day +457, the likely consequence of high-velocity, H-rich material being excited by a reverse shock. A relatively flat X-ray light curve is observed that cannot be modeled using Inverse Compton scattering processes alone, but requires an additional energy source most likely originating from the SN-CSM interaction. In addition, we see the first overtone of CO emission near 2.3 μ m on day +152, signaling the formation of molecules and dust in the SN ejecta and is the first time CO has been detected in a Type IIL SN. We compare SN 2013by with Type IIP SNe, whose spectra show the rarely observed SN-to-SNR transition in varying degrees and conclude that Type IIL SNe may enter the remnant phase at earlier epochs than their Type IIP counterparts.

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.

Genome-wide analysis of KAP1, the 7SK snRNP complex, and RNA polymerase II

Directory of Open Access Journals (Sweden)

Ryan P. McNamara

2016-03-01

Full Text Available The transition of RNA polymerase II (Pol II from transcription initiation into productive elongation in eukaryotic cells is regulated by the P-TEFb kinase, which phosphorylates the C-terminal domain of paused Pol II at promoter-proximal regions. Our recent study found that P-TEFb (in an inhibited state bound to the 7SK snRNP complex interacts with the KAP1/TRIM28 transcriptional regulator, and that KAP1 and the 7SK snRNP co-occupy most gene promoters containing paused Pol II. Here we provide a detailed experimental description and analysis of the ChIP-seq datasets that have been deposited into Gene Expression Omnibus (GEO: GS72622, so that independent groups can replicate and expand upon these findings. We propose these datasets would provide valuable information for researchers studying mechanisms of transcriptional regulation including Pol II pausing and pause release. Keywords: P-TEFb/7SK snRNP, KAP1, RNA polymerase II, ChIP-seq, Transcription elongation

Phase transitions and thermal expansion in Ni51- x Mn36 + x Sn13 alloys

Science.gov (United States)

Kaletina, Yu. V.; Gerasimov, E. G.; Kazantsev, V. A.; Kaletin, A. Yu.

2017-10-01

Thermal expansion and structural and magnetic phase transitions in alloys of the Ni-Mn-Sn system have been investigated. The spontaneous martensitic transformation in Ni51-xMn36 + xSn13 (0 ≤ x ≤ 3) alloys is found to be accompanied by high jumps in the temperature dependences of the linear thermal expansion. The relative change in the linear sizes of these alloys at the martensitic transformation is 1.5 × 10-3. There are no anomalies in the magnetic-ordering temperature range in the temperature dependences of the coefficient of linear thermal expansion. The differences in the behavior of linear thermal expansion at the martensitic transformation in Ni51-xMn36 + xSn13 (0 ≤ x ≤ 3) and Ni47Mn40Sn13( x = 4) alloys have been established.

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.

Lattice parameter values and phase transitions for the Cu2Cd1-zMnzSnSe4 and Cu2Cd1-zFezSnSe4 alloys

International Nuclear Information System (INIS)

Moreno, E.; Quintero, M.; Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P.; Delgado, G.E.; Contreras, J.E.; Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L.; Henao, J.A.; Macias, M.A.

2009-01-01

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu 2 Cd 0.8 Fe 0.2 SnSe 4 as well as for Cu 2 Cd 0.2 Fe 0.8 SnSe 4 the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter σ decreases as Cd is replaced by either Mn and/or Fe. For the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems, only two single solid phase fields, the tetragonal stannite α(I4-bar2m) and the wurtz-stannite δ (Pmn2 1 ) structures were found to occur in the diagram. In addition to the tetragonal stannite α phase extra X-ray diffraction lines due to MnSe and/or FeSe 2 were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

Ab initio CASSCF study of the electronic structure of the transition-metal alkylidene-like complexes Mo-M[prime]H[sub 2] (M[prime] = C, Si, Ge, and Sn)

Energy Technology Data Exchange (ETDEWEB)

Marquez, A.; Sanz, J.F. (Universidad de Sevilla (Spain))

1992-12-02

Experimental and theoretical research on the electronic and geometric structure of transition-metal-carbenes and -alkylidenes is an active area in chemistry nowadays due to their potential activity in catalysis and in organic and organometallic synthesis. A theoretical investigation of the electronic structure of the high-valent, transition-metal, alkylidene-like complexes MoM[prime]H[sub 2] (M[prime] = C, Si, Ge, and Sn) is reported. Based on ab initio calculations carried out at the complete active space multiconfiguration self-consistent field (CASSCF) level, the molecular structure of the ground state and some low-lying excited states have been determined. For M[prime] = C, Si, and Ge, the ground state has C[sub 2v] symmetry (state [sup 5]B[sub 1]) and corresponds to pairing each electron of the M[prime]H[sub 2] triplet [sup 3]B[sub 1] with an electron of Mo ([sup 7]S). In the case of MoSnH[sub 2], the lowest state is bent (C[sub s] symmetry, state [sup 7]A[prime]), the out-of-plane angle being 68[degrees], and dissociates into SnH[sub 2] ([sup 1]A[sub 1]) + Mo ([sup 7]S). Dissociation energies, potential energy profiles for the dissociation, harmonic force constants in terms of internal symmetry coordinates, and vibrational frequencies are reported. The comparison of these properties with those of their pentacarbonylated homologous (CO)[sub 5]M[double bond]M[prime]H[sub 2] shows that the carbene-like (Fischer) type of complexation is stronger than the alkylidene-like one (Schrock). 28 refs., 4 figs., 6 tabs.

The low-lying quartet electronic states of group 14 diatomic borides XB (X = C, Si, Ge, Sn, Pb)

Science.gov (United States)

Pontes, Marcelo A. P.; de Oliveira, Marcos H.; Fernandes, Gabriel F. S.; Da Motta Neto, Joaquim D.; Ferrão, Luiz F. A.; Machado, Francisco B. C.

2018-04-01

The present work focuses in the characterization of the low-lying quartet electronic and spin-orbit states of diatomic borides XB, in which X is an element of group 14 (C, Si, Ge, Sn, PB). The wavefunction was obtained at the CASSCF/MRCI level with a quintuple-ζ quality basis set. Scalar relativistic effects were also taken into account. A systematic and comparative analysis of the spectroscopic properties for the title molecular series was carried out, showing that the (1)4Π→X4Σ- transition band is expected to be measurable by emission spectroscopy to the GeB, SnB and PbB molecules, as already observed for the lighter CB and SiB species.

M1 transitions between superdeformed states in 195Tl

International Nuclear Information System (INIS)

Zheng Xing; Xingqu Chen; Xiaochun Wang

1996-01-01

Using a triaxial-particle-rotor model, the quadrupole and dipole transition energies, kinematic and dynamic moments of inertia, electromagnetic transition probabilities and the relative intensity of the E2 γ-transitions are calculated for superdeformed bands in 195 Tl. A strong perturbation effect of rotation on transition energies and M1 and E2 transitions of superdeformed states is investigated. The total M1 transitions, enhanced by internal conversion, are expected to compete strongly with the E2 γ-ray at low spins in the superdeformed 195 Tl nucleus. (author)

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...

Viscous behavior of (Sn61.9Pb38.1)100-xREx (x=0, 0.1, 0.3, 1 wt%) solder alloys

International Nuclear Information System (INIS)

Wu Yuqin; Bian Xiufang; Zhao Yan; Li Xuelian; Zhang Yanning; Tian Yongsheng; Lv Xiaoqian

2008-01-01

The viscous behavior of (Sn 61.9 Pb 38.1 ) 100-x RE x (x=0, 0.1, 0.3, 1 wt%) solder alloys has been investigated by a torsional oscillation viscometer. The structural transition temperature T ' increases with increasing addition of RE elements. Above T ' , the viscosities of melts increase with increasing addition of RE, and are fitted well with the Arrhenius equation. The time dependence of viscosity at the measured temperature below T ' follows the exponential relaxation function and reflects the process of the structural transition in the melt, which can be considered as the thermodynamic equilibrium process. The thermodynamic equilibrium relaxation time τ eq increases with both the equilibrium viscosity η eq and the discrepancy in viscosity (Δη), between the initial state and the equilibrium state. However, it decreases with the measured temperature T. The size of clusters in the melts increases with increasing of viscosity and is restricted by the thermodynamic equilibrium conditions

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

Phase change memory based on SnSe{sub 4} alloy

Energy Technology Data Exchange (ETDEWEB)

Karanja, J.M.; Karimi, P.M.; Njoroge, W.K. [Physics Department, Kenyatta University, P.O. Box 43844, Nairobi (Kenya); Wamwangi, D.M., E-mail: Daniel.Wamwangi@wits.ac.za [School of Physics, University of the Witwatersrand, Private Bag 3, 2050 (South Africa)

2013-01-01

A phase change alloy has been synthesized and characterized. The reversible phase transitions between amorphous and crystalline states of SnSe{sub 4} films have been studied using variable electrical pulses and X-ray diffraction. Temperature dependent sheet resistance measurements have shown two distinct resistivity states of more than two orders of magnitude. This high electrical contrast makes the alloy suitable for nonvolatile phase change memory applications. X-ray diffraction has attributed the large electrical contrast to an amorphous–crystalline phase transition. The nonvolatile memory cells have been fabricated using a simple sandwich structure (metal/chalcogenide thin film/metal). A threshold voltage of 3.71 V has been determined for this phase change random access memory cell. Memory switching was initiated using the voltage pulses of 3.71 V, 90 ns, 1.3 V and 26 μs, for the crystallization and amorphization process, respectively. - Highlights: ► Phase transition of SnSe{sub 4} alloys with high set resistivity of 1.43 Ωm ► High transition temperatures of 174 °C ► Transition due to amorphous–crystalline changes ► Threshold switching at a high threshold voltage of 3.71 V.

Phase transition and water incorporation into Eu2Sn2O7 pyrochlore at high pressure

Science.gov (United States)

Zhang, F. X.; Lang, M.; Ewing, R. C.

2016-04-01

Structural changes of europium stannate pyrochlore, Eu2Sn2O7, have been investigated at high pressures with in situ Raman spectroscopy, photoluminescence (PL), and synchrotron X-ray diffraction (XRD) techniques. The XRD measurements suggest that a pressure-induced phase transition starts at 34.4 GPa. The PL spectrum from Eu3+ cations also suggests a phase transition above 36 GPa. XRD analysis shows that the unit cell of the cubic phase deviates from the equation of state at pressures above 23.8 GPa. This is due to the incorporation of water from the pressure medium in the structure at high pressures, which is confirmed by optical spectroscopy measurements.

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.)

Investigation of low-lying dipole strength in {sup 124}Sn

Energy Technology Data Exchange (ETDEWEB)

Symochko, D.; Aumann, T.; Duchene, M.; Knoerzer, M.; Pietralla, N.; Scheit, H. [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); Bhike, M.; Kelley, J.; Tornow, W. [Department for Physics, Duke University (United States); Derya, V.; Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Isaak, J.; Loeher, B.; Savran, D. [ExtreMe Matter Institute EMMI and Research Division, Darmstadt (Germany); Tonchev, A. [Lawrence Livermore National Laboratory (United States); Werner, V. [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); WNSL, Yale University (United States)

2014-07-01

Dipole excitations in the semi-magic {sup 124}Sn nucleus were studied in (γ,γ') reactions using the γ{sup 3}-high-efficiency detector setup. The experiment was carried out with quasimonoenergetic photon beams provided by the HIγS facility at the TUNL in the energy range from 5.2 to 8.6 MeV at 15 different energies. Measurements allowed to identify near 80 new transitions to the ground state, obtain reduced transition probabilities and assign parity quantum numbers to the observed excited states. Besides, the γ-γ coincidence technique gave access to the γ-decay pattern of the Pygmy Dipole Resonance, e.g. it was possible to analyse the branching ratios to the first excited 2{sup +} state. Investigations were made as a part of the experimental campaign aimed to obtain a complete picture of dipole strength function evolution in Sn isotopes - from stable {sup 112}Sn to short-lived {sup 134}Sn.

Brillouin scattering, DSC, dielectric and X-ray diffraction studies of phase transitions in antiferroelectric PbHfO{sub 3}:Sn

Energy Technology Data Exchange (ETDEWEB)

Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Kim, Tae Hyun [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Gągor, Anna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Jankowska-Sumara, Irena [Institute of Physics, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków (Poland); Majchrowski, Andrzej [Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Kojima, Seiji [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

2015-02-15

Highlights: • Phase transition mechanisms were studied in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3.} • Acoustic phonons showed anomalies at 472 and 426 K due to phase transitions. • Brillouin data showed evidence for presence of polar clusters in paraelectric phase. • An order-disorder mechanism of the PE to AFE2 transition was proved. - Abstract: Specific heat, dielectric, powder X-ray diffraction and Brillouin scattering studies of phase transitions in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3} crystal were performed. The specific heat data revealed clear anomalies at T{sub 1} = 473.5 and T{sub 2} = 426.3 K on cooling, which could be attributed to onset of first order phase transitions from the paraelectric (PE) phase to an intermediate antiferroelectric phase (AFE2) and the AFE2 phase to another antiferroelectric phase (AFE1), respectively. The estimated entropy changes at T{sub 1} and T{sub 2} pointed to mainly an order-disorder and displacive character of these transitions, respectively. X-ray diffraction data showed a complex superstructure of the intermediate phase with a = 11.895(6) Å, b = 11.936(4) Å, c = 8.223(3) Å at 453 K. Brillouin studies revealed pronounced softening of longitudinal acoustic (LA) mode in the PE phase associated with its broadening. The broadening and softening exhibited maximum values at T{sub 1}. Additional acoustic anomalies, that is, abrupt frequency shifts for LA and transverse acoustic (TA) modes were also observed at T{sub 2}. Brillouin scattering data also showed presence of a broad central peak (CP) that exhibited highest intensity at T{sub 1}. The observed temperature dependences of acoustic modes and CP indicate order-disorder character of the FE to AFE2 phase transition and importance of polar precursor clusters in the PE phase. The obtained data also suggest that the intermediate antiferroelectric phases in Sn{sup 4+} doped PbHfO{sub 3} and PbZrO{sub 3} may have very similar structures

Conversion-electron spectroscopy and gamma-gamma angular correlation measurements in {sup 116}Sn

Energy Technology Data Exchange (ETDEWEB)

Cross, D.S.; Pore, J.L.; Andreoiu, C.; Chester, A.S.; Noakes, B.; Starosta, K.; Voss, P. [Simon Fraser University, Department of Chemistry, Burnaby, BC (Canada); Ball, G.C.; Bender, P.C.; Churchman, R.; Garnsworthy, A.B.; Hackman, G.; Miller, D.T. [TRIUMF, Vancouver, BC (Canada); Demand, G.A.; Diaz Varela, A.; Dunlop, R.; Garrett, P.E.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A.T.; Liblong, A.; Svensson, C.E.; Wilson, J.M. [University of Guelph, Department of Physics, Guelph, ON (Canada); Kanungo, R. [Saint Mary' s University, Department of Astronomy and Physics, Halifax, NS (Canada); Petrache, C.M. [CSNSM, CNRS-IN2P3, Universite Paris-Saclay, Orsay (France); Wang, Z.M. [Simon Fraser University, Department of Chemistry, Burnaby, BC (Canada); TRIUMF, Vancouver, BC (Canada); Wood, J.L. [Georgia Institute of Technology, School of Physics, Atlanta, GA (United States); Yates, S.W. [University of Kentucky, Departments of Chemistry and Physics and Astronomy, Lexington, KY (United States)

2017-11-15

The {sup 116}Sn nucleus was studied via the β{sup -} decay of {sup 116}In utilizing the 8π spectrometer and its auxiliary detectors at TRIUMF-ISAC. The resulting K-shell conversion coefficients, K/L ratios, and multipole mixing ratios are presented. The 2{sub 3}{sup +} → 2{sub 1}{sup +} 931 keV and 2{sub 2}{sup +} → 2{sub 1}{sup +} 819 keV transition mixing ratios were re-measured and found to be δ = +1.8{sub -0.5}{sup +0.7} and -1.83(8), respectively. Newly measured mixing ratios for transitions among the low-lying I{sup π} = 4{sup +} states in {sup 116}Sn, when combined with γ-ray intensity data, suggest that the 2529 keV 4{sub 2}{sup +} state possesses a neutron broken-pair admixture in addition to its dominant proton 2p-2h component. (orig.)

Pressure induced structural phase transition in SnS—An ab initio study

Indian Academy of Sciences (India)

Unknown

Abstract. The structural behaviour of SnS under pressure has been investigated by first principle density functional ... tural phase transition from orthorhombic type to monoclinic type structure around 17 GPa which is in good agreement with the ... is achieved by performing the electronic structure and total energy calculation ...

Thermal properties and phase transition in the fluoride, (NH{sub 4}){sub 3}SnF{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Kartashev, A.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Astafijev Krasnoyarsk State Pedagogical University, 660049 Krasnoyarsk (Russian Federation); Gorev, M.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Bogdanov, E.V. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk (Russian Federation); Flerov, I.N. [Kirensky Institute of Physics, Siberian Department of the Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Laptash, N.M. [Institute of Chemistry, Far Eastern Department of the Russian Academy of Sciences, 690022 Vladivostok (Russian Federation)

2016-05-15

Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH{sub 4}){sub 3}SnF{sub 7} for a wide range of temperatures and pressures. Large entropy (δS{sub 0}=22 J/mol K) and elastic deformation (δ(ΔV/V){sub 0}=0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS{sub 0}=32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH{sub 4}){sub 3}TiF{sub 7}, undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH{sub 4}){sub 3}SnF{sub 7}, contrary to (NH{sub 4}){sub 3}TiF{sub 7}, characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH{sub 4}){sub 3}SnF{sub 7} was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH{sub 4}){sub 3}SnF{sub 7} is associated with very large total entropy change of ΔS{sub 0}=32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH{sub 4}){sub 3}TiF{sub 7} undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH{sub 4}){sub 3}SnF{sub 7} undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC{sub p} and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH{sub 4}){sub 3}SnF{sub 7}. • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

Electronic Topological Transitions in CuNiMnAl and CuNiMnSn under pressure from first principles study

Science.gov (United States)

Rambabu, P.; Kanchana, V.

2018-06-01

A detailed study on quaternary ordered full Heusler alloys CuNiMnAl and CuNiMnSn at ambient and under different compressions is presented using first principles electronic structure calculations. Both the compounds are found to possess ferromagnetic nature at ambient with magnetic moment of Mn being 3.14 μB and 3.35 μB respectively in CuNiMnAl and CuNiMnSn. The total magnetic moment for both the compounds is found to decrease under compression. Fermi surface (FS) topology change is observed in both compounds under pressure at V/V0 = 0.90, further leading to Electronic Topological Transitions (ETTs) and is evidenced by the anomalies visualized in density of states and elastic constants under compression.

Nature of the magnetic ground state in the mixed valence compound CeRuSn: a single-crystal study

International Nuclear Information System (INIS)

Fikáček, J; Prokleška, J; Prchal, J; Custers, J; Sechovský, V

2013-01-01

We report on detailed low-temperature measurements of the magnetization, the specific heat and the electrical resistivity on high-quality CeRuSn single crystals. The compound orders antiferromagnetically at T N = 2.8 K with the Ce 3+ ions locked within the a–c plane of the monoclinic structure. Magnetization shows that below T N CeRuSn undergoes a metamagnetic transition when applying a magnetic field of 1.5 and 0.8 T along the a- and c-axis, respectively. This transition manifests in a tremendous negative jump of ∼25% in the magnetoresistance. The value of the saturated magnetization along the easy magnetization direction (c-axis) and the magnetic entropy above T N derived from specific heat data correspond to the scenario of only one third of the Ce ions in the compound being trivalent and carrying a stable Ce 3+ magnetic moment, whereas the other two thirds of the Ce ions are in a nonmagnetic tetravalent and/or mixed valence state. This is consistent with the low-temperature CeRuSn crystal structure i.e., a superstructure consisting of three unit cells of the CeCoAl type piled up along the c-axis, and in which the Ce 3+ ions are characterized by large distances from the Ru ligands while the Ce–Ru distances of the other Ce ions are much shorter causing a strong 4f-ligand hybridization and hence leading to tetravalent and/or mixed valence Ce ions. (paper)

Short-wavelength out-of-band EUV emission from Sn laser-produced plasma

Science.gov (United States)

Torretti, F.; Schupp, R.; Kurilovich, D.; Bayerle, A.; Scheers, J.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

2018-02-01

We present the results of spectroscopic measurements in the extreme ultraviolet regime (7-17 nm) of molten tin microdroplets illuminated by a high-intensity 3 J, 60 ns Nd:YAG laser pulse. The strong 13.5 nm emission from this laser-produced plasma (LPP) is of relevance for next-generation nanolithography machines. Here, we focus on the shorter wavelength features between 7 and 12 nm which have so far remained poorly investigated despite their diagnostic relevance. Using flexible atomic code calculations and local thermodynamic equilibrium arguments, we show that the line features in this region of the spectrum can be explained by transitions from high-lying configurations within the Sn{}8+-Sn{}15+ ions. The dominant transitions for all ions but Sn{}8+ are found to be electric-dipole transitions towards the n = 4 ground state from the core-excited configuration in which a 4p electron is promoted to the 5s subshell. Our results resolve some long-standing spectroscopic issues and provide reliable charge state identification for Sn LPP, which could be employed as a useful tool for diagnostic purposes.

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)

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.

First-principles analysis of ferroelectric transition in MnSnO3 and MnTiO3 perovskites

Science.gov (United States)

Kang, Sung Gu

2018-06-01

The ferroelectric instabilities of an artificially adopted Pnma structure in low tolerance perovskites have been explored (Kang et al., 2017) [4], where an unstable A-site environment was reported to be the major driving source for the low tolerance perovskites to exhibit ferroelectric instability. This study examined the ferroelectric transition of two magnetic perovskite materials, MnSnO3 and MnTiO3, in Pnma phase. Phase transitions to the Pnma phase at elevated pressures were observed. MnSnO3, which has a lower (larger) tolerance factor (B-site cation radius), showed a higher ferroelectric mode amplitude than MnTiO3. The distribution of the bond length of Mn-O and the mean quadratic elongation (QE) of octahedra (SnO6 or TiO6) were investigated for structural analysis. However, MnTiO3 showed a larger spontaneous polarization than MnSnO3 due to high Born effective charges of titanium. This study is useful because it provides a valuable pathway to the design of promising multiferroic materials.

High-field magnetization studies of U2T2Sn (T=Co, Ir, Pt) compounds

International Nuclear Information System (INIS)

Prokes, K.; Nakotte, H.; de Boer, F.R.

1995-01-01

High-field magnetization measurements at 4.2 K on U 2 T 2 Sn (T = Co, Ir and Pt) compounds have been performed on free and fixed powders up to 57 T. An antiferromagnetic ground state of U 2 Pt 2 Sn is corroborated by a metamagnetic transition at 22 T with very small hysteresis going up and down with field. U 2 Co 2 Sn and U 2 Ir 2 Sn show no metamagnetic transition up to 57 T which is in agreement with the non-magnetic ground state of these compounds. In all cases, the maximum applied field is not sufficient to achieve saturation. The short-pulse measurements presented here are compared with previous results obtained in quasi-static fields up to 35 T

Unusually large magnetic moments in the normal state and superconducting state of Sn nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hung, Chi-Hang; Lee, Chi-Hung; Hsu, Chien-Kang; Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Wu, Chun-Ming; Li, Wen-Hsien, E-mail: whli@phy.ncu.edu.tw [National Central University, Department of Physics and Center for Neutron Beam Applications (China)

2013-09-15

We report on the observations of spontaneous magnetic moments in the normal as well as in the superconducting states of a 9 nm Sn nanoparticle assembly, through X-ray diffraction, magnetization, ac magnetic susceptibility, and neutron diffraction measurements. The saturation magnetization reaches an unexpectedly large value of 1.04 emu/g at 5 K, with a temperature profile that can be described by Bloch's law with an exponent of b = 1.8. A magnetic moment of Left-Pointing-Angle-Bracket {mu}{sub Z} Right-Pointing-Angle-Bracket = 0.38 {mu}{sub B} develops after cooling from 260 to 4 K. Superconductivity develops below T{sub C} = 3.98 K, which is 7 % higher than the T{sub C} = 3.72 K of bulk Sn. Surprisingly, an addition magnetic moment of Left-Pointing-Angle-Bracket {mu}{sub Z} Right-Pointing-Angle-Bracket = 0.05 {mu}{sub B} develops upon entering the superconducting state.

Improved superconducting properties of La{sub 3}Co{sub 4}Sn{sub 13} with indium substitution

Energy Technology Data Exchange (ETDEWEB)

Neha, P.; Srivastava, P. [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Jha, R. [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); National Physical Laboratory, New Delhi 110012 (India); Shruti [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Awana, V.P.S. [National Physical Laboratory, New Delhi 110012 (India); Patnaik, S., E-mail: spatnaik@mail.jnu.ac.in [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)

2016-04-25

We report two fold increase in superconducting transition temperature of La{sub 3}Co{sub 4}Sn{sub 13} by substituting indium at the tin site. The transition temperature of this skutterudite related compound is observed to increase from 2.5 K to 5.1 K for 10% indium substituted sample. The band structure and density of states calculations also indicate such a possibility. The compounds exhibit type-II superconductivity and the values of lower critical field (H{sub c1}), upper critical field (H{sub c2}), Ginzburg–Landau coherence length (ξ), penetration depth (λ) and GL parameter (κ) are estimated to be 0.0028 T, 0.68 T, 21.6 nm, 33.2 nm and 1.53 respectively for La{sub 3}Co{sub 4}Sn{sub 11.7}In{sub 1.3}. Hydrostatic external pressure leads to decrease in transition temperature and the calculated pressure coefficient is −0.311 K/GPa. Flux pinning and vortex activation energies also improved with indium addition. Only positive frequencies are observed in phonon dispersion curve that relate to the absence of charge density wave or structural instability in the normal state. - Highlights: • Superconducting transition temperature of La{sub 3}Co{sub 4}Sn{sub 13} increases two fold by indium substitution. • Band structure and all basic superconducting parameters (e.g,. H{sub c1}, H{sub c2}, ξ,λ and κ are ascertained. • Dependence of superconducting properties under external pressure is studied.

Electronic and magnetic properties of SnS2 monolayer doped with 4d transition metals

Science.gov (United States)

Xiao, Wen-Zhi; Xiao, Gang; Rong, Qing-Yan; Chen, Qiao; Wang, Ling-Ling

2017-09-01

We investigate the electronic structures and magnetic properties of SnS2 monolayers substitutionally doped with 4-d transition-metal through systematic first principles calculations. The doped complexes exhibit interesting electronic and magnetic behaviors, depending on the interplay between crystal field splitting, Hund's rule, and 4d levels. The system doped with Y is nonmagnetic metal. Both the Zr- and Pd-doped systems remain nonmagnetic semiconductors. Doping results in half-metallic states for Nb-, Ru-, Rh-, Ag, and Cd doped cases, and magnetic semiconductors for systems with Mo and Tc dopants. In particular, the Nb- and Mo-doped systems display long-ranged ferromagnetic ordering with Curie temperature above room temperature, which are primarily attributable to the double-exchange mechanism, and the p-d/p-p hybridizations, respectively. Moreover, The Mo-doped system has excellent energetic stability and flexible mechanical stability, and also possesses remarkable dynamic and thermal (500 K) stability. Our studies demonstrate that Nb- and Mo-doped SnS2 monolayers are promising candidates for preparing 2D diluted magnetic semiconductors, and hence will be a helpful clue for experimentalists.

Towards 100Sn: Studies on neutron-deficient even isotopes of tin

International Nuclear Information System (INIS)

Rathke, G.E.

1987-02-01

Neutron-deficient 108,106,104 Sn isotopes were produced by heavy ion induced fusion reactions using high-intensity 59 Ni beams from the UNILAC of the GSI. Their decay properties were studied by techniques of gamma and conversion electron spectroscopy employing the mass separator on-line to the UNILAC. Earlier information on the 108 Sn → 108 In and 106 Sn → 106 In decays was complemented and improved in the course of this work. The new nucleus 104 Sn and its decay to excited states in 104 In was identified and studied for the first time. These investigations yield the following results: the mass of 104 Sn and of nuclei linked to it by alpha decay or proton radioactivity, 108 Te, 112 Xe and 109 I, 113 Cs, respectively were determined from the measured Q EC value of 104 Sn and the known mass value of 104 In. These are nuclei very close or beyond the proton drip line. In addition, information on the quenching of the fast Gamow-Teller beta decay of the even neutron-deficient tin isotopes was obtained. This complements investigations on the N = 50 isotones 94 Ru and 96 Pd, and allows a systematic comparison of these transition strengths for nuclei near the doubly magic 100 Sn. The spreading of the vertical strokeπg 9/2 -1 vg 7/2 , 1 + > configuration over several states, due to residual interactions, and the centroid energies of these magnetic dipole states were determined for the corresponding odd-odd indium isotopes. (orig./HSI)

State-of-the-art Sn2+-based ternary oxides as photocatalysts for water splitting: electronic structures and optoelectronic properties

KAUST Repository

Noureldine, Dalal

2016-09-19

Developing visible light responsive metal oxide photocatalysts is a challenge that must be conquered to achieve high efficiency for water splitting or hydrogen evolution reactions. Valence band engineering is possible by forming ternary oxides using the combination of a metal cation with an s2d10 electronic configuration and a transition metal oxide with a d0 configuration. Many (Sn2+, Bi3+, Pb2+)-based ternary metal oxide photocatalysts have been reported for hydrogen and/or oxygen evolution under visible irradiation. Sn2+-based materials have attracted particular attention because tin is inexpensive, abundant and more environmentally friendly than lead or bismuth. In this review, we provide a fruitful library for Sn2+-based photocatalysts that have been reported to evolve hydrogen using sacrificial reagents, including SnNb2O6, Sn2Nb2O7, SnTaxNb2−xO6, SnTa2O6, Sn2Ta2O7, SnWO4 (α and β phases), SnSb2O6·nH2O, and Sn2TiO4. The synthesis method used in the literature and the resultant morphology and crystal structure of each compound are discussed. The density functional theory (DFT) calculations of the electronic structure and density of states are provided, and the consequent optoelectronic properties such as band gap, nature of the bandgap, dielectric constant, and effective masses are summarized. This review will help highlight the main challenges for Sn2+-based materials.

State-of-the-art Sn2+-based ternary oxides as photocatalysts for water splitting: electronic structures and optoelectronic properties

KAUST Repository

Noureldine, Dalal; Takanabe, Kazuhiro

2016-01-01

Developing visible light responsive metal oxide photocatalysts is a challenge that must be conquered to achieve high efficiency for water splitting or hydrogen evolution reactions. Valence band engineering is possible by forming ternary oxides using the combination of a metal cation with an s2d10 electronic configuration and a transition metal oxide with a d0 configuration. Many (Sn2+, Bi3+, Pb2+)-based ternary metal oxide photocatalysts have been reported for hydrogen and/or oxygen evolution under visible irradiation. Sn2+-based materials have attracted particular attention because tin is inexpensive, abundant and more environmentally friendly than lead or bismuth. In this review, we provide a fruitful library for Sn2+-based photocatalysts that have been reported to evolve hydrogen using sacrificial reagents, including SnNb2O6, Sn2Nb2O7, SnTaxNb2−xO6, SnTa2O6, Sn2Ta2O7, SnWO4 (α and β phases), SnSb2O6·nH2O, and Sn2TiO4. The synthesis method used in the literature and the resultant morphology and crystal structure of each compound are discussed. The density functional theory (DFT) calculations of the electronic structure and density of states are provided, and the consequent optoelectronic properties such as band gap, nature of the bandgap, dielectric constant, and effective masses are summarized. This review will help highlight the main challenges for Sn2+-based materials.

Search of the chemical change of the sup(119m)Sn (Tsub(1/2) = 293 days) radioactive decay rate

International Nuclear Information System (INIS)

Makariunas, K.; Makariuniene, E.; Dragunas, A.

1983-01-01

The differences in decay rates of the nuclear isomer sup(119m)Sn (Tsub(1/2) = 293 days; the strongly converted M4 transition) have been measured for different chemical compounds. The experimental results show that the sup(119m)Sn nuclei in the telluride SnTe decay faster than in the metal β-Sn and in the dioxide SnO 2 [the relative change Δlambda/lambda the decay probability lambda is +(3.6+-1.4)x10 -4 ]. No measurable difference between the decay rates of sup(119m)Sn in β-Sn and SnO 2 has been observed [Δlambda/lambda = -(0.1+-1.2)x10 -4 ], irrespective of the great difference in electronic structure of the tin atoms. The results cannot be explained by considering the internal conversion of the valence electrons only. It is necessary to assume that the chemical changes of the decay rate are strongly influenced by the chemical changes of the probabilities of the internal conversion of electrons of the inner shells of the atom. This conclusion is confirmed by theoretical calculations. (Auth.)

Cr 3d surface and bulk states in Sn1-xCrxTe/Cr crystals

International Nuclear Information System (INIS)

Guziewicz, E.; Szamota-Sadowska, K.; Kowalski, B.J.; Grodzicka, E.; Story, T.; Orlowski, B.A.; Johnson, R.L.

1997-01-01

We report a new approach to investigate metal-semiconductor interface formation. Photoemission spectroscopy was applied in order to investigate the clean surface of a Sn 0.97 Cr 0.03 Te crystal and to observe its changes under sequential deposition of small amounts of Cr atoms. In order to analyse the Cr 3d contribution to the valence band, the Fano-type resonance tuned to the Cr 3p-3d transmission was used. The experiment was designed to follow the Sn 0.97 Cr 0.03 Te/Cr interface formation process. At the clean Sn 0.97 Cr 0.03 Te surface, the Cr 3d states contribution to the valence band was found to be positioned 0.8 eV below Fermi level. After the Cr deposition processes the contribution shifted to a higher binding energy and another contribution 5.8 eV below the Fermi level also observed. (author)

Phase Transitions in CsSnCl3 and CsPbBr3 An NMR and NQR Study

Science.gov (United States)

Sharma, Surendra; Weiden, Norbert; Weiss, Alarich

1991-04-01

The phase transitions in CsSnCl3 and CsPbBr3 have been studied by X-ray powder diffraction, by 81Br-NQR and by 'H-, 119Sn-, and 113Cs-NMR. At room temperature in air CsSnCl3 forms a hydrate which can be dehydrated to the monoclinic phase II of CsSnCl3. The high temperature phase I has the Perovskite structure, as the X-ray and NMR experiments show. The three phases of CsPbBr3, known from literature, have been corroborated. The results are discussed in the framework of the group ABX3, A = alkalimetal ion, B = IV main group ion, and X = Halogen ion

Magnetism in 3d transition metal doped SnO

KAUST Repository

Albar, Arwa

2016-09-12

Using first principles calculations, we investigate the structural and electronic properties of 3d transition metal doped SnO. We examine the stability of different doping sites using formation energy calculations. The magnetic behavior of the dopant atoms is found to be complex because of interplay between strong structural relaxation, spin-lattice coupling, and crystal field splitting. The interaction between dopant atoms is analyzed as a function of their separation, showing that clustering typically counteracts spin polarization. An exception is found for V doping, which thus turns out to be a promising candidate for realizing a magnetic p-type oxide.

Viscous behavior of (Sn{sub 61.9}Pb{sub 38.1}){sub 100-x}RE{sub x} (x=0, 0.1, 0.3, 1 wt%) solder alloys

Energy Technology Data Exchange (ETDEWEB)

Wu Yuqin [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China); Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China)], E-mail: xfbian@sdu.edu.cn; Zhao Yan; Li Xuelian; Zhang Yanning; Tian Yongsheng; Lv Xiaoqian [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China)

2008-05-19

The viscous behavior of (Sn{sub 61.9}Pb{sub 38.1}){sub 100-x}RE{sub x} (x=0, 0.1, 0.3, 1 wt%) solder alloys has been investigated by a torsional oscillation viscometer. The structural transition temperature T{sup '} increases with increasing addition of RE elements. Above T{sup '}, the viscosities of melts increase with increasing addition of RE, and are fitted well with the Arrhenius equation. The time dependence of viscosity at the measured temperature below T{sup '} follows the exponential relaxation function and reflects the process of the structural transition in the melt, which can be considered as the thermodynamic equilibrium process. The thermodynamic equilibrium relaxation time {tau}{sub eq} increases with both the equilibrium viscosity {eta}{sub eq} and the discrepancy in viscosity ({delta}{eta}), between the initial state and the equilibrium state. However, it decreases with the measured temperature T. The size of clusters in the melts increases with increasing of viscosity and is restricted by the thermodynamic equilibrium conditions.

Photosensitive thin-film In/p-Pb{sub x}Sn{sub 1-x}S Schottky barriers: Fabrication and properties

Energy Technology Data Exchange (ETDEWEB)

Gremenok, V. F., E-mail: gremenok@ifttp.bas-net.by [Scientific-Practical Center of the National Academy of Sciences of Belarus State Scientific and Production Association (Belarus); Rud' , V. Yu., E-mail: rudvas.spb@gmail.com [St. Petersburg State Polytechnic University (Russian Federation); Rud' , Yu. V. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Bashkirov, S. A.; Ivanov, V. A. [Scientific-Practical Center of the National Academy of Sciences of Belarus State Scientific and Production Association (Belarus)

2011-08-15

Thin Pb{sub x}Sn{sub 1-x}S films are obtained by the 'hot-wall' method at substrate temperatures of 210-330 Degree-Sign C. The microstructure, composition, morphology, and electrical characteristics of films are investigated. On the basis of the obtained films, photosensitive In/p-Pb{sub x}Sn{sub 1-x}S Schottky barriers are fabricated for the first time. The photosensivity spectra of these structures are investigated, and the character of interband transitions and the band-gap values are determined from them. The conclusion is drawn that Pb{sub x}Sn{sub 1-x}S thin polycrystalline films may be used in solar-energy converters.

Fragmentation of neutron hole states in /sup 111,115/Sn

International Nuclear Information System (INIS)

Vdovin, A.I.; Thao, N.D.; Solov'ev, V.G.; Stoyanov, C.

1983-01-01

The quasiparticle-phonon model of the nucleus with inclusion of the interaction of one-quasiparticle states with a large number of states of the quasiparticle + phonon and quasiparticle + two phonons type is used to calculate the fragmentation of the deep hole subshells 2p/sub 1/2/, 2p/sub 3/2/, 1f/sub 5/2/, and others in the isotopes /sup 111,115/Sn. Satisfactory agreement is obtained with the results of recent (d,t) experiments in the even isotopes of tin

Spectroscopy of the doubly magic nucleus 100Sn and its decay

International Nuclear Information System (INIS)

Hinke, Christoph B.

2010-01-01

-Teller transition strength in the decay of 100 Sn turned out to be a surprisingly high value of B GT =9.1 +4.8 -2.3 . In the daughter nucleus 100 In five gamma rays with transition energies of E γ =96 keV, 141 keV, 436 keV, 1297 keV and 2048 keV deexciting the populated 1 + -state after the beta decay of 100 Sn could be observed for the first time. Different scenarios for the level structure in 100 In are discussed but can unfortunately not be distinguished on the basis of the present data. For each scenario a ground state to ground state Q EC value of the decay was calculated. (orig.)

Martensitic transformation and phase stability of In-doped Ni-Mn-Sn shape memory alloys from first-principles calculations

International Nuclear Information System (INIS)

Xiao, H. B.; Yang, C. P.; Wang, R. L.; Luo, X.; Marchenkov, V. V.

2014-01-01

The effect of the alloying element Indium (In) on the martensitic transition, magnetic properties, and phase stabilities of Ni 8 Mn 6 Sn 2−x In x shape memory alloys has been investigated using the first-principles pseudopotential plane-wave method based on density functional theory. The energy difference between the austenitic and martensitic phases was found to increase with increasing In content, which implies an enhancement of the martensitic phase transition temperature (T M ). Moreover, the formation energy results indicate that In-doping increases the relative stability of Ni 8 Mn 6 Sn 2−x In x both in austenite and martensite. This results from a reduction in density of states near the Fermi level regions caused by Ni-3d–In-5p hybridization when Sn is replaced by In. The equilibrium equation of state results show that the alloys Ni 8 Mn 6 Sn 2−x In x exhibit an energetically degenerated effect for an In content of x = ∼1.5. This implies the coexistence of antiparallel and parallel configurations in the austenite.

Influence of the State of the Tungsten Tip on STM Topographic Images of SnSe Surfaces

Science.gov (United States)

Ly, Trinh Thi; Kim, Jungdae

2018-03-01

Tin selenide (SnSe) has recently attracted significant attention because of its excellent thermoelectric properties with a figure of merit (ZT) of 2.6. Previous scanning tunneling microscopy (STM) studies of SnSe surfaces showed that only Sn atoms are resolved in topographic images due to the dominant contribution of the Sn 5 p z states in tunneling. However, when the state of the tungsten (W) tip changes from a typical four-lobe d state such as d xy or {d_{{x^2} - {y^2}}} to a two-lobe {d_{{z^2}}} state, the atomic features observed on the SnSe surface in STM topography can be dramatically altered. In this report, we present the results of a systematic study on the influence of the W tip's states on the STM images of SnSe surfaces. Sn atoms are observed with much stronger corrugation amplitude and smaller apparent radius when the tip is in a {d_{{z^2}}} state. In addition, the atomic features of the Se atoms become visible because of the sharply focused shape of the W {d_{{z^2}}} state. We expect our results to provide important information for establishing a better understanding of the microscopic nature of SnSe surfaces.

Transitions between compound states of spherical nuclei

International Nuclear Information System (INIS)

Kadmenskii, S.G.; Markushev, V.P.; Furman, V.I.

1980-01-01

Wigner's statistical matrices are used to study the average reduced g widths and their dispersion for g transitions from a compound state c to another state f, with a lower excitation energy but of arbitrary complexity, for spherical nuclei. It is found that the Porter--Thomas distribution holds for the g widths for all cases of practical interest. In g transitions between compound states c and c' with E/sub g/< or =2 MeV, the most important transitions are M1 transitions involving the major many-quasiparticle components of state c and E1 transitions involving the minor components of state c. It is shown that the strength functions predicted by the various theories for M1 and E1 transitions between compound states with E/sub g/< or =2 MeV are similar. Preference is assigned to the M1-transition version because of experimental results on (n,ga) reactions with thermal and resonance neutrons

First principles study of structural, electronic and magnetic properties of SnGe n (0, ±1) ( n = 1–17) clusters

Science.gov (United States)

Djaadi, Soumaia; Eddine Aiadi, Kamal; Mahtout, Sofiane

2018-04-01

The structures, relative stability and magnetic properties of pure Ge n +1, neutral cationic and anionic SnGe n (n = 1–17) clusters have been investigated by using the first principles density functional theory implemented in SIESTA packages. We find that with the increasing of cluster size, the Ge n +1 and SnGe n (0, ±1) clusters tend to adopt compact structures. It has been also found that the Sn atom occupied a peripheral position for SnGe n clusters when n 12. The structural and electronic properties such as optimized geometries, fragmentation energy, binding energy per atom, HOMO–LUMO gaps and second-order differences in energy of the pure Ge n +1 and SnGe n clusters in their ground state are calculated and analyzed. All isomers of neutral SnGe n clusters are generally nonmagnetic except for n = 1 and 4, where the total spin magnetic moments is 2μ b. The total (DOS) and partial density of states of these clusters have been calculated to understand the origin of peculiar magnetic properties. The cluster size dependence of vertical ionization potentials, vertical electronic affinities, chemical hardness, adiabatic electron affinities and adiabatic ionization potentials have been calculated and discussed.

Lead-free soldering: Investigation of the Cu-Sn-Sb system along the Sn:Sb = 1:1 isopleth

Energy Technology Data Exchange (ETDEWEB)

Yuan, Y. [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Borzone, G., E-mail: borzone@chimica.unige.it [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Zanicchi, G.; Delsante, S. [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy)

2011-02-03

Research highlights: > In the electronics industry, the solder alloys commonly used for assembly belong to the Sn-Pb system. Fulfilment of the EU RoHS (reduction of hazardous substances) requires the development of new lead-free alloys for applications in electronics, with the same or possibly better characteristics than the traditional Sn-Pb alloys. > This research concerns the investigation of the constitutional properties of the Cu-Sn-Sb system which is considered as lead-free replacement for high-temperature applications. - Abstract: The Cu-Sn-Sb system has been experimentally investigated by a combination of optical microscopy, differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). DSC was used to identify a total number of five invariant ternary reactions and the Sn:Sb = 1:1 isopleth section up to 65 at.% Cu was constructed by combining the DSC data with the EPMA analyses of annealed alloys and literature information. The composition limits of the binary phases were detected.

E0 and E2 decay of low-lying 0+ states in the even-even nuclei 206Pb, 208Po, 112-120 Sn and 112114Cd

International Nuclear Information System (INIS)

Julin, Rauno.

1979-04-01

Several new methods of in-beam conversion-electron and γ-ray spectrometry, applicable in the determination of E0 and E2 decay properties of low-lying 0 + states in even-mass nuclei, have been developed. The main attention has been paid to direct lifetime-measurement and coincidence methods based on the use of the natural pulsing of a cyclotron beam. With the aid of these methods, the similarity of the absolute decay rates of the two-neutron-hole 0 + 2 states in the N = 124 nuclei 206 Pb and 208 Po has been shown. A systematic investigation of the de-excitation of the 0 + 2 and 0 + 3 states in 112 , 11 4 , 116 , 118 , 120 Sn has been carried out. Twelve E0 transitions connecting the 0 + states have been observed, including very strong low-energy E0 transitions between the excited 0 + states, and several absolute transition probabilities have been determined. Furthermore, the new techniques have been applied successfully in determining the absolute E0 and E2 transition rates from the 0 + 2 and 0 + 3 states in 112 Cd and 114 Cd. The use of isotope-shift data in the calculation of the monopole strengths in 206 Pb and 208 Po is discussed. The results on even Sn and Cd nuclei are discussed within the framework of the coexistence of different shapes and of configuration mixing. (author)

Magnetoresistance in CePtSn under high hydrostatic pressures

International Nuclear Information System (INIS)

Misek, M.; Prokleska, J.; Javorsky, P.; Sechovsky, V.

2009-01-01

We report the evolution of magnetic-history dependent antiferromagnetic phases in CePtSn. We concentrate on the magnetoresistance in magnetic fields up to 14 T applied along the crystallographic b-axis, measured on a CePtSn single crystal subjected to hydrostatic pressure (p ≤ 2.2 GPa) generated in a double-layered CuBe/NiCrAl piston cylinder cell. We observe a gradual increase of the critical field B c LF of the low field (LF) transition up to ∼1.2 GPa where only one transition is observed at ∼11.5 T. For pressures above 1.2 GPa we observe two transitions again and B c LF decreases with further increasing pressure to reach B c LF ∼7.5T at 2.5 GPa. The position of the high field (HF) transition remains almost unaffected by applied pressure. A scenario considering the spin-slip AF structure in CePtSn is briefly discussed.

Distribution of impurity states and charge transport in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Liu, Yuanfeng; Makongo, Julien P.A. [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Page, Alexander [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Sahoo, Pranati [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Stokes, Kevin [The Advanced Materials Research Institute, Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

2016-02-15

Energy filtering of charge carriers in a semiconducting matrix using atomically coherent nanostructures can lead to a significant improvement of the thermoelectric figure of merit of the resulting composite. In this work, several half-Heusler/full-Heusler (HH/FH) nanocomposites with general compositions Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (0≤x≤0.15 and y=0.005, 0.01 and 0.025) were synthesized in order to investigate the behavior of extrinsic carriers at the HH/FH interfaces. Electronic transport data showed that energy filtering of carriers at the HH/FH interfaces in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} samples strongly depends on the doping level (y value) as well as the energy levels occupied by impurity states in the samples. For example, it was found that carrier filtering at HH/FH interfaces is negligible in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (y=0.01 and 0.025) composites where donor states originating from Sb dopant dominate electronic conduction. However, we observed a drastic decrease in the effective carrier density upon introduction of HH/FH interfaces for the mechanically alloyed Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 0.995}Sb{sub 0.005} samples where donor states from unintentional Fe impurities contribute the largest fraction of conduction electrons. This work demonstrates the ability to synergistically integrate the concepts of doping and energy filtering through nanostructuring for the optimization of electronic transport in semiconductors. - Graphical abstract: Electronic transport in semiconducting half-Heusler (HH) matrices containing full-Heusler (FH) nanoinclusions strongly depends on the energy distribution of impurity states within the HH matrix with respect to the magnitude of the potential energy barrier at the HH/FH interfaces. - Highlights: • Coherent nanostructures enhanced thermoelectric behavior of half-Heusler alloys. • Nanostructures act as energy filter of

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.

Investigations of low- and high-spin states of sup 1 sup 3 sup 2 La

CERN Document Server

Kumar, V; Singh, R P; Muralithar, S; Bhowmik, R K

2003-01-01

The fusion evaporation reaction sup 1 sup 2 sup 2 Sn( sup 1 sup 4 N,4n) sup 1 sup 3 sup 2 La was used to populate the high-spin states of sup 1 sup 3 sup 2 La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2 sup - and the isomeric state 6 sup -. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the pi h sub 1 sub 1 sub / sub 2 x nu h sub 1 sub 1 sub / sub 2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies in the spin assignment of the band head. (orig.)

Numerical analysis of In_xGa_1_−_xN/SnS and Al_xGa_1_−_xN/SnS heterojunction solar cells

International Nuclear Information System (INIS)

Lin, Shuo; Li, Xirong; Pan, Huaqing; Chen, Huanting; Li, Xiuyan; Li, Yan; Zhou, Jinrong

2016-01-01

Highlights: • In_xGa_1_−_xN/SnS and Al_xGa_1_−_xN/SnS solar cells are studied by numerical analysis. • Performances of In_xGa_1_−_xN/SnS solar cells enhanced with decreasing In content. • The electron barrier leads to the degraded efficiency of Al_xGa_1_−_xN/SnS solar cells. • GaN/SnS solar cell exhibits the highest efficiency 26.34%. - Abstract: In this work the photovoltaic properties of In_xGa_1_−_xN/SnS and Al_xGa_1_−_xN/SnS heterojunction solar cells are studied by numerical analysis. The photovoltaic performances of In_xGa_1_−_xN/SnS solar cells are enhanced with the decreasing In content and the GaN/SnS solar cell exhibits the highest efficiency. The efficiencies of GaN/SnS solar cell improve with the increased SnS thickness and the reduced GaN thickness. For the Al_xGa_1_−_xN/SnS solar cells, there is electron barrier in the Al_xGa_1_−_xN/SnS interface. The electron barrier becomes larger with increasing Al content and lead to the degraded efficiency of Al_xGa_1_−_xN/SnS solar cells. The simulation contributes to designing and fabricating SnS solar cells.

Synthesis and superconductivity of In-doped SnTe nanostructures

Directory of Open Access Journals (Sweden)

Piranavan Kumaravadivel

2017-07-01

Full Text Available InxSn1−xTe is a time-reversal invariant candidate 3D topological superconductor derived from doping the topological crystalline insulator SnTe with indium. The ability to synthesize low-dimensional nanostructures of indium-doped SnTe is key for realizing the promise they hold in future spintronic and quantum information processing applications. But hitherto only bulk synthesized crystals and nanoplates have been used to study the superconducting properties. Here for the first time we synthesize InxSn1−xTe nanostructures including nanowires and nanoribbons, which show superconducting transitions. In some of the lower dimensional morphologies, we observe signs of more than one superconducting transition and the absence of complete superconductivity. We propose that material inhomogeneity, such as indium inhomogeneity and possible impurities from the metal catalyst, is amplified in the transport characteristics of the smaller nanostructures and is responsible for this mixed behavior. Our work represents the first demonstration of InxSn1−xTe nanowires with the onset of superconductivity, and points to the need for improving the material quality for future applications.

Fragmentation of neutron hole states in the sup(111,115)Sn

International Nuclear Information System (INIS)

Vdovin, A.I.; Nguen Din' Tkhao; Solov'ev, V.G.; Stoyanov, Ch.

1983-01-01

In the framework of the quasiparticle-phonon nuclear model, taking into account an interaction of one-quasiparticle states with large number states of the (quasiparticle + phonon) and (quasiparticle + two phonons) type, the fragmentation is calculated for deep hole subshells 2psub(1/2), 2psub(3/2), 1fsub(5/2) and others in the isotopes sup(111,115)Sn. A satisfactory agreement with the results of recent experiments on the (d, t) reactions on even tin isotopes is obtained

Strain-free Ge/GeSiSn Quantum Cascade Lasers Based on L-Valley Intersubband Transitions

National Research Council Canada - National Science Library

Soret, R. A; Sun, G; Cheng, H; Menendez, J; Khurgin, J

2007-01-01

The authors propose a Ge/Ge0.76Si0.19Sn0.05 quantum cascade laser using intersubband transitions at L valleys of the conduction band which has a clean offset of 150 meV situated below other energy valleys Gamma and X...

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.

The effect of increasing membrane curvature on the phase transition and mixing behavior of a dimyristoyl-sn-glycero-3-phosphatidylcholine/distearoyl-sn-glycero-3-phosphatidylcholine lipid mixture as studied by Fourier transform infrared spectroscopy and differential scanning calorimetry

DEFF Research Database (Denmark)

Brumm, T.; Jørgensen, Kent; Mouritsen, Ole G.

1996-01-01

The phase transition behavior of a lipid bilayer of dimyristoyl-sn-glycero-3-phosphalidylcholine/distearoyl-sn- glycero-3-phosphatidylcholine (DMPC-d54/DSPC) (1:1) on a solid support with varying curvatures was investigated with differential scanning calorimetry, infrared spectroscopy, and model...... of the liquidus point can be understood as a reduction of the lateral pressure in the bilayer with increasing curvature. The shift of the solidus line is interpreted as a result of the increased demixing of the two components in the two-phase region with increasing curvature due to lowering of the lateral...

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

Martensitic transition, inverse magnetocaloric effect and shape memory characteristics in Mn{sub 48−x}Cu{sub x}Ni{sub 42}Sn{sub 10} Heusler alloys

Energy Technology Data Exchange (ETDEWEB)

Liu, Changqin [Department of Physics, Shanghai University, Shanghai 200444 (China); Li, Zhe [Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Zhang, Yuanlei [Department of Physics, Shanghai University, Shanghai 200444 (China); Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Liu, Yang; Sun, Junkun; Huang, Yinsheng; Kang, Baojuan [Department of Physics, Shanghai University, Shanghai 200444 (China); Xu, Kun [Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Deng, Dongmei [Department of Physics, Shanghai University, Shanghai 200444 (China); Jing, Chao, E-mail: cjing@staff.shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China)

2017-03-01

In this paper, we have systematically prepared a serials of polycrystalline Mn{sub 48−x}Cu{sub x}Ni{sub 42}Sn{sub 10} alloys (x=0, 1, 3, 5, 6, 8, 10 and 12) and investigated the influence of the Cu doping on martensitic transition (MT) as well as magnetic properties. Experimental results indicate that the MT temperature and the martensite Curie temperature (T{sub c}{sup M}) shift to high temperature with increasing the substitution of Cu (from Mn rich alloy to Ni rich alloy), while the austenite Curie temperature (T{sub c}{sup A}) is almost unchanged. It was found that the structures undergo L2{sub 1} and 4O with the increasing of Cu concentration near room temperature. Therefore, the magnetostructural transition can be tuned by appropriate Cu doping in these alloys. Moreover, we mainly studied the multiple functional properties for inverse magnetocaloric effect and shape memory characteristics associated with the martensitic transition. A large positive isothermal entropy change of Mn{sub 48}Ni{sub 42}Sn{sub 10} was obtained, and the maximum transition entropy change achieves about 48 J/kg K as x=8. In addition, a considerable temperature-induced spontaneous strain with the value of 0.16% was obtained for Mn{sub 48}Ni{sub 42}Sn{sub 10} alloys.

Study of GeSn Alloy for Low Cost Monolithic Mid Infrared Quantum Well Sensor

Directory of Open Access Journals (Sweden)

Prakash PAREEK

2017-02-01

Full Text Available This paper focuses on theoretical study of Tin incorporated group IV alloys particularly GeSn and design of quantum well sensor for mid infrared sensing applications. Initially, the physics behind the selection of material for midinfrared sensor is explained. The importance of controlling strain in GeSn alloy is also explained. The physical background and motivation for incorporation of Tin(Sn in Germanium is briefly narrated. Eigen energy states for different Sn concentrations are obtained for strain compensated quantum well in G valley conduction band (GCB, heavy hole (HH band and light hole (LH band by solving coupled Schrödinger and Poisson equations simultaneously. Sn concentration dependent absorption spectra for HH- GCB transition reveals that significant absorption observed in mid infrared range (3-5 µm. So, Ge1-x Snx quantum well can be used for mid infrared sensing applications.

Ferromagnetic ordering and halfmetallic state in a shandite: Co3Sn2S2

Science.gov (United States)

Schnelle, Walter; Leithe-Jasper, Andreas; Rosner, Helge; Weihrich, Richard

2013-03-01

The rapid advance in spintronics challenges an improved understanding of the underlying microscopic properties. Here, we present a joint experimental and theoretical study of Co3Sn2S2 (shandite) and related compounds. From magnetic susceptibility, specific heat and magneto-transport measurements on a shandite single crystal sample we find a phase transition to a ferromagnetic metallic state at 177 K with a saturation moment of 0.92 μB/f.u. Full potential electronic structure calculations within the local spin density approximation result in a halfmetallic ferromagnetic groundstate with a moment of 1 μB/f.u. and a tiny gap in the minority spin channel. The calculated structure optimization and structure variations show that the size of the gap is rather sensitive to the lattice geometry. Possiblities to stabilize the halfmetallic ferromagnetic behavior by various substitutions have been studied theoretically and will be discussed.

Transition State Gauche Effects Control the Torquoselectivities of the Electrocyclizations of Chiral 1-Azatrienes.

Science.gov (United States)

Patel, Ashay; Vella, Joseph R; Ma, Zhi-Xiong; Hsung, R P; Houk, K N

2015-12-04

Hsung et al. have reported a series of torquoselective electrocyclizations of chiral 1-azahexa-1E,3Z,5E-trienes that yield functionalized dihydropyridines. To understand the origins of the torquoselectivities of these azaelectrocyclizations, we modeled these electrocyclic ring closures using the M06-2X density functional. A new stereochemical model that rationalizes the observed 1,2 stereoinduction emerges from these computations. This model is an improvement and generalization of the "inside-alkoxy" model used to rationalize stereoselectivities of the 1,3-dipolar cycloaddition of chiral allyl ethers and emphasizes a stabilizing hyperconjugative effect, which we have termed a transition state gauche effect. This stereoelectronic effect controls the conformational preferences at the electrocyclization transition states, and only in one of the allowed disrotatory electrocyclization transition states is the ideal stereoelectronic arrangement achieved without the introduction of a steric clash. Computational experiments confirm the role of this effect as a stereodeterminant since substrates with electropositive groups and electronegative groups have different conformational preferences at the transition state and undergo ring closure with divergent stereochemical outcomes. This predicted reversal of stereoselectivity for the ring closures of several silyl substituted azatrienes have been demonstrated experimentally.

Above-bandgap optical properties of biaxially strained GeSn alloys grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Richard D’Costa, Vijay, E-mail: elevrd@nus.edu.sg; Wang, Wei; Zhou, Qian; Yeo, Yee-Chia, E-mail: eleyeoyc@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Soon Tok, Eng [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

2014-01-13

The complex dielectric function of biaxially strained Ge{sub 1−x}Sn{sub x} (0 ≤ x ≤ 0.17) alloys grown on Ge (100) has been determined by spectroscopic ellipsometry from 1.2 to 4.7 eV. The effect of substitutional Sn incorporation and the epitaxial strain on the energy transitions E{sub 1}, E{sub 1} + Δ{sub 1}, E{sub 0}′, and E{sub 2} of GeSn alloys is investigated. Our results indicate that the strained GeSn alloys show Ge-like electronic bandstructure with all the transitions shifted downward due to the alloying of Sn. The strain dependence of E{sub 1} and E{sub 1} + Δ{sub 1} transitions is explained using the deformation potential theory, and values of −5.4 ± 0.4 eV and 3.8 ± 0.5 eV are obtained for the hydrostatic and shear deformation potentials, respectively.

Compositional dependence of the band-gap of Ge{sub 1−x−y}Si{sub x}Sn{sub y} alloys

Energy Technology Data Exchange (ETDEWEB)

Wendav, Torsten, E-mail: wendav@physik.hu-berlin.de [AG Theoretische Optik & Photonik, Humboldt Universität zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Fischer, Inga A.; Oehme, Michael; Schulze, Jörg [Institut für Halbleitertechnik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart (Germany); Montanari, Michele; Zoellner, Marvin Hartwig; Klesse, Wolfgang [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Capellini, Giovanni [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Dipartimento di Scienze, Università Roma Tre, Viale Marconi 446, 00146 Roma (Italy); Driesch, Nils von den; Buca, Dan [Peter Grünberg Institute 9 (PGI 9) and JARA-Fundamentals of Future Information Technologies, Forschungszentrum Jülich, 52428 Jülich (Germany); Busch, Kurt [AG Theoretische Optik & Photonik, Humboldt Universität zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Max-Born-Institut, Max-Born-Str. 2 A, 12489 Berlin (Germany)

2016-06-13

The group-IV semiconductor alloy Ge{sub 1−x−y}Si{sub x}Sn{sub y} has recently attracted great interest due to its prospective potential for use in optoelectronics, electronics, and photovoltaics. Here, we investigate molecular beam epitaxy grown Ge{sub 1−x−y}Si{sub x}Sn{sub y} alloys lattice-matched to Ge with large Si and Sn concentrations of up to 42% and 10%, respectively. The samples were characterized in detail by Rutherford backscattering/channeling spectroscopy for composition and crystal quality, x-ray diffraction for strain determination, and photoluminescence spectroscopy for the assessment of band-gap energies. Moreover, the experimentally extracted material parameters were used to determine the SiSn bowing and to make predictions about the optical transition energy.

Boson forbidden transitions and their manifestation in spherical nuclei

International Nuclear Information System (INIS)

Stoyanov, Ch.

2002-01-01

For the correct description of the 'boson forbidden' transitions it is necessary to go beyond the quasi-boson approximation and to take into account the fermion structure of the phonons. Once it done it is quantitative description of the transitions is possible within the simplest model based on the separable residual interactions. Calculations of the forbidden E1-transitions in 120 Sn, 144 Sm and 144 Nd are presented. Analysis of some low-energy M1-transitions is made using IBM-2. The discussed examples reveal the complex properties of the low-lying excited states

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.

α-Sn and β-Sn precipitates in annealed epitaxial Si_0.95Sn_0.05

DEFF Research Database (Denmark)

Fyhn, M.F.; Chevallier, J.; Larsen, A.N.

1999-01-01

-Sn and beta-Sn crystallites. The presence of alpha-Sn at temperatures far above the bulk alpha beta transition temperature is explained by interface and pressure effects; the latter is likely to be due to the difference in thermal expansion of the precipitates and the matrix.......-temperature molecular-beam epitaxy on Si (001) and relaxed Si1-xGex substrates. Two different phases of solid Sn were identified in the annealed layers: the semiconductor phase, alpha-Sn, and the metallic phase beta-Sn The precipitates were found to consist of either only beta-Sn or to contain crystallites of both...... solid Sn phases. The orientations, the sizes and the relative number densities of the alpha-Sn and beta-Sn crystallites were investigated. in situ heating and cooling experiments were performed in the transmission electron microscope to study the melting and solidification characteristics of the alpha...

Spectroelectrochemical Study of Carbon Monoxide and Ethanol Oxidation on Pt/C, PtSn(3:1/C and PtSn(1:1/C Catalysts

Directory of Open Access Journals (Sweden)

Rubén Rizo

2016-09-01

Full Text Available PtSn-based catalysts are one of the most active materials toward that contribute ethanol oxidation reaction (EOR. In order to gain a better understanding of the Sn influence on the carbon monoxide (principal catalyst poison and ethanol oxidation reactions in acidic media, a systematic spectroelectrochemical study was carried out. With this end, carbon-supported PtSnx (x = 0, 1/3 and 1 materials were synthesized and employed as anodic catalysts for both reactions. In situ Fourier transform infrared spectroscopy (FTIRS and differential electrochemical mass spectrometry (DEMS indicate that Sn diminishes the amount of bridge bonded CO (COB and greatly improves the CO tolerance of Pt-based catalysts. Regarding the effect of Sn loading on the EOR, it enhances the catalytic activity and decreases the onset potential. FTIRS and DEMS analysis indicate that the C-C bond scission occurs at low overpotentials and at the same potential values regardless of the Sn loading, although the amount of C-C bond breaking decreases with the rise of Sn in the catalytic material. Therefore, the elevated catalytic activity toward the EOR at PtSn-based electrodes is mainly associated with the improved CO tolerance and the incomplete oxidation of ethanol to form acetic acid and acetaldehyde species, causing the formation of a higher amount of both C2 products with the rise of Sn loading.

Synthesis of Nanocrystalline SnOx (x = 1–2 Thin Film Using a Chemical Bath Deposition Method with Improved Deposition Time, Temperature and pH

Directory of Open Access Journals (Sweden)

Zulkarnain Zainal

2011-09-01

Full Text Available Nanocrystalline SnOx (x = 1–2 thin films were prepared on glass substrates by a simple chemical bath deposition method. Triethanolamine was used as complexing agent to decrease time and temperature of deposition and shift the pH of the solution to the noncorrosive region. The films were characterized for composition, surface morphology, structure and optical properties. X-ray diffraction analysis confirms that SnOx thin films consist of a polycrystalline structure with an average grain size of 36 nm. Atomic force microscopy studies show a uniform grain distribution without pinholes. The elemental composition was evaluated by energy dispersive X-ray spectroscopy. The average O/Sn atomic percentage ratio is 1.72. Band gap energy and optical transition were determined from optical absorbance data. The film was found to exhibit direct and indirect transitions in the visible spectrum with band gap values of about 3.9 and 3.7 eV, respectively. The optical transmittance in the visible region is 82%. The SnOx nanocrystals exhibit an ultraviolet emission band centered at 392 nm in the vicinity of the band edge, which is attributed to the well-known exciton transition in SnOx. Photosensitivity was detected in the positive region under illumination with white light.

Aql X-1 transition towards the soft (banana) state accompanied by radio/NIR detection

Science.gov (United States)

Sivakoff, G. R.; Miller-Jones, J.; Fox, O.; Linares, M.; Altamirano, D.; Russell, D.

2009-11-01

The currently active neutron star transient and atoll source Aql X-1 (Linares et al., ATEL #2288) has begun the transition from the hard (extreme island) state to the soft (banana) state (Rodriguez et al. ATEL #2299). This transition likely began around 2009 Nov 15 (MJD = 55150). The latest RXTE PCA observation (2009 Nov 17, MJD=55152.17+/-0.02, 2-60 keV fractional rms variability amplitude of ~11% for 0.1-10 Hz) indicates that the source is in the intermediate (island) state.

ac loss and dc critical current densities of Nb3Sn tapes by the solid state diffusion process

International Nuclear Information System (INIS)

Suenaga, M.; Klamut, C.; Bussiere, J.F.

1976-01-01

The effects of metallurgical processing on 60 Hz ac losses and dc critical currents in Nb 3 Sn tapes fabricated by the solid state diffusion technique were investigated. An addition of Al to the Cu--Sn alloy for the matrix resulted in large reduction in the ac losses of Nb 3 Sn tapes, but the highest linear critical current densities were observed in Nb 3 Sn tapes produced with a Nb-1 wt percent Zr core in a Cu-13 wt percent Sn matrix. Values of the losses and the critical currents in these tapes can meet the present requirements for the ac superconducting power cables

Spectroscopy of the doubly magic nucleus {sup 100}Sn and its decay

Energy Technology Data Exchange (ETDEWEB)

Hinke, Christoph B.

2010-07-23

}{sub 0}}=3.29{+-}0.20 MeV. The resultant Gamow-Teller transition strength in the decay of {sup 100}Sn turned out to be a surprisingly high value of B{sub GT}=9.1{sup +4.8}{sub -2.3}. In the daughter nucleus {sup 100}In five gamma rays with transition energies of E{sub {gamma}}=96 keV, 141 keV, 436 keV, 1297 keV and 2048 keV deexciting the populated 1{sup +}-state after the beta decay of {sup 100}Sn could be observed for the first time. Different scenarios for the level structure in {sup 100}In are discussed but can unfortunately not be distinguished on the basis of the present data. For each scenario a ground state to ground state Q{sub EC} value of the decay was calculated. (orig.)

Pressure dependence of the Curie temperature in the Kondo lattice compound YbNiSn

Energy Technology Data Exchange (ETDEWEB)

Sparn, G; Thompson, J D [Los Alamos National Lab., NM (United States); Hamzic, A [Dept. of Physics, Zagreb (Yugoslavia)

1992-04-03

We have measured the magnetic susceptibility (2 K < T < 300 K) and the electrical resistivity under pressure (1.2 K < T < 300 K; p < 20 kbar) of the Kondo lattice compound YbNiSn, which may be considered as the ''hole'' analogue of the isostructural compound CeNiSn. In contrast with CeNiSn, YbNiSn does not show an energy gap at low temperatures but instead undergoes a magnetic phase transition at T{sub M} = 5.5 K. The magnetic state might be either a weakly ferromagnetic or a complex antiferromagnetic state. By applying pressure the room temperature resistance {rho}{sub RT} decreases, while T{sub M} increases. This behavior can be interpreted with respect to Doniach's Kondo necklace model as a decrease in the local exchange coupling constant J with increasing pressure, which reduces Kondo spin compensation and favors long-range magnetic order. These results show that the idea that YbNiSn is the hole counterpart to CeNiSn holds well for the properties such as dT{sub M}/dP and d{rho}{sub RT}/dP but that it fails in more detailed aspects, such as the origin of the energy gap formation. (orig.).

Lattice parameter values and phase transitions for the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloys

Energy Technology Data Exchange (ETDEWEB)

Moreno, E. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Quintero, M., E-mail: mquinter@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Delgado, G.E.; Contreras, J.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Henao, J.A.; Macias, M.A. [Grupo de Investigacion en Quimica Estructural (GIQUE), Facultad de Ciencias, Escuela de Quimica, Universidad Industrial de Santander, Apartado aereo 678, Bucaramanga (Colombia)

2009-11-03

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu{sub 2}Cd{sub 0.8}Fe{sub 0.2}SnSe{sub 4} as well as for Cu{sub 2}Cd{sub 0.2}Fe{sub 0.8}SnSe{sub 4} the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter sigma decreases as Cd is replaced by either Mn and/or Fe. For the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems, only two single solid phase fields, the tetragonal stannite alpha(I4-bar2m) and the wurtz-stannite delta (Pmn2{sub 1}) structures were found to occur in the diagram. In addition to the tetragonal stannite alpha phase extra X-ray diffraction lines due to MnSe and/or FeSe{sub 2} were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

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.

M1 transitions between low-lying states in the sdg-IBM-2

Science.gov (United States)

Casperson, Robert; Werner, Volker

2006-10-01

The interplay between collective and single-particle degrees of freedom for nuclei in the A=90 region have recently been under investigation. In Molybdenum and Ruthenium nuclei, collective symmetric and mixed-symmetric structures have been identified, while in Zirconium, underlying shell-structure plays an enhanced role. Collective symmetric structures appear when protons and neutrons are in phase, whereas mixed-symmetric structures occur when they are not. The one-phonon 2^+ mixed-symmetric state was identified from strong M1 transitions to the 2^+1 state. Similar transitions were observed between higher-spin states, and are predicted by the shell model. These phenomena will be investigated within the sdg Interacting Boson Model 2 in order to obtain a better understanding about the structure of the states involved, and results from first model calculations will be presented. Work supported by US DOE under grant number DE-FG02-91ER-40609.

Effect of excess Ni on martensitic transition, exchange bias and inverse magnetocaloric effect in Ni{sub 2+x}Mn{sub 1.4−x}Sn{sub 0.6} alloy

Energy Technology Data Exchange (ETDEWEB)

Ray, Mayukh K., E-mail: mayukh.ray@saha.ac.in; Bagani, K.; Banerjee, S., E-mail: sangam.banerjee@saha.ac.in

2014-07-05

Highlights: • Excess Ni causes an increase in the martensite transition temperature. • The system Ni{sub 2+x}Mn{sub 1.4−x}Sn{sub 0.6} exhibit multifunctional properties. • The RCP and EB increases continuously with excess Ni concentration in the system. • Antiferromagnetic interaction increases with excess Ni concentration. - Abstract: The martensitic transition, exchange bias (EB) and inverse magnetocaloric effect (IMCE) of bulk Ni{sub 2+x}Mn{sub 1.4−x}Sn{sub 0.6} (x = 0, 0.06, 0.12, 0.18) Heusler alloy is investigated in this paper. Substitution of Mn by Ni causes an increase in the martensite transition temperature (T{sub M}), decrease in Curie temperature of austenite phase (T{sub C}{sup A}) and also a decrease in the saturation magnetic moment (M{sub sat}). While the decrease in T{sub C}{sup A} and M{sub sat} is explained by the dilution of the magnetic subsystems and on the other hand the increase in T{sub M} is due to the increase of valence electron concentration per atom (e/a). All the alloys shows EB effect below a certain temperature (T{sup ∗}) and EB field (H{sub EB}) value is almost thrice in magnitude for x = 0.18 sample compared to x = 0 sample at 5 K. In these alloys, Ni/Mn atoms at regular site couples antiferromagnetically (AFM) with the excess Ni atoms at Mn or Sn sites and this AFM coupling plays the key role in the observation of EB. For the IMCE, the change in magnetic entropy (ΔS{sub M}) initially increased with excess Ni concentration upto x = 0.12 but then a drastic fall in ΔS{sub M} value is observed for the sample x = 0.18 but the relative cooling power (RCP) value is increased continuously with the excess Ni concentration.

Spin glass behaviour in the rare earth ternary stannide HoRh1.2Sn3.9

NARCIS (Netherlands)

Lázaro, F.J.; van de Pasch, A.W.M.; Flokstra, Jakob

1987-01-01

Dynamic susceptibility measurements on HoRh1.2Sn3.9 have been performed in the vicinity of its magnetic transition at TM = 1.7 K. χ'(T) exhibits a cusp-like peak, which is substantially depressed when an external field of a few mT is applied. Below TM a strong frequency dependence of the

Effect of superconducting transition on microcreep of high-TC ceramics

International Nuclear Information System (INIS)

Soldatov, V.P.; Natsik, V.D.; Chajkovskaya, N.M.

1991-01-01

Influence of N-S and S-N transition on microplastic deformation kinetics of YBa 2 Cu 3 O 7-δ ceramic samples by there deformation in liquid nitrogen under microscreep conditions is studied. Superconductivity disruption in the sample was achieved by critical value currents. It is shown, that N-S transition increases creep rate,whereas S-N transition slows it down. Microplastic deformation rate by sample state change may very by two-eight times. Influence of heat expansion on creep kinetics as probable associated effect is analyzed. Assumption is expressed, that stimulated transition effect on microplastic deformation of ceramic samples is related to change of their electron state in the area of Josephson contacts between grains

RCI Simulation for EUV spectra from Sn ions

International Nuclear Information System (INIS)

Kagawa, T; Tanuma, H; Ohashi, H; Nishihara, K

2007-01-01

Using the relativistic-configuration-interaction atomic structure code, RCI simulations for EUV spectra from Sn 10+ , Sn 11+ and Sn 12+ ions are carried out, where it is assumed that each ion is embedded in a LTE plasma with the electron temperature of 30 eV. To make clear assignment of the measured spectra, the value of the excitation energy limit, which is introduced to limit the number of excited states in the simulation, is changed to see the excitation-energy-limit dependence of the spectral shape. The simulated spectra are obtained as a superposition of line intensities due to all possible transitions between two states whose excitation energy from the ground state is lower than the excitation energy limit assumed. The RCI simulated spectra are compared to the spectra measured with the chargeexchange- collision experiment in which a rare gas such as Xe or He as a target is bombarded by a charge-selected tin ion. Applicability of the LTE model to a decay model in the charge exchange collision experiment is also discussed

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.

Calculated Fermi surface properties of LaSn3 and YSn3 under pressure

International Nuclear Information System (INIS)

Kanchana, V.

2012-01-01

The electronic structure, Fermi surface and elastic properties of the iso-structural and iso-electronic LaSn 3 and YSn 3 intermetallic compounds are studied under pressure within the frame work of density functional theory including spin-orbit coupling. The LaSn 3 Fermi surface consists of two sheets, of which the second is very complex. Under pressure a third sheet appears around compression V/V 0 =0.94, while a small topology changes in the second sheet is seen at compression V/V 0 =0.90. This may be in accordance with the anomalous behavior in the superconducting transition temperature observed in LaSn 3 , which has been suggested to reflect a Fermi surface topological transition, along with a non-monotonic pressure dependence of the density of states at the Fermi level. The similar behavior is not observed in YSn 3 for which the Fermi surface includes three sheets already at ambient conditions, and the topology remains unchanged under pressure. The reason for the difference in behavior between LaSn 3 and YSn 3 is the role of spin-orbit coupling and the hybridization of La-4f state with the Sn-p state in the vicinity of the Fermi level, which is well explained using the band structure calculation. The elastic constants and related mechanical properties are calculated at ambient as well as at elevated pressures. The elastic constants increase with pressure for both compounds and satisfy the conditions for mechanical stability under pressure. (author)

Superconductivity in SnO: a nonmagnetic analog to Fe-based superconductors?

Science.gov (United States)

Forthaus, M K; Sengupta, K; Heyer, O; Christensen, N E; Svane, A; Syassen, K; Khomskii, D I; Lorenz, T; Abd-Elmeguid, M M

2010-10-08

We discovered that under pressure SnO with α-PbO structure, the same structure as in many Fe-based superconductors, e.g., β-FeSe, undergoes a transition to a superconducting state for p≳6 GPa with a maximum Tc of 1.4 K at p=9.3 GPa. The pressure dependence of Tc reveals a domelike shape and superconductivity disappears for p≳16 GPa. It is further shown from band structure calculations that SnO under pressure exhibits a Fermi surface topology similar to that reported for some Fe-based superconductors and that the nesting between the hole and electron pockets correlates with the change of Tc as a function of pressure.

Superconductivity in SnO: A Nonmagnetic Analog to Fe-Based Superconductors?

DEFF Research Database (Denmark)

Forthaus, M. K.; Sengupta, K.; Heyer, O.

2010-01-01

We discovered that under pressure SnO with α-PbO structure, the same structure as in many Fe-based superconductors, e.g., β-FeSe, undergoes a transition to a superconducting state for p≳6  GPa with a maximum Tc of 1.4 K at p=9.3  GPa. The pressure dependence of Tc reveals a domelike shape...... and superconductivity disappears for p≳16  GPa. It is further shown from band structure calculations that SnO under pressure exhibits a Fermi surface topology similar to that reported for some Fe-based superconductors and that the nesting between the hole and electron pockets correlates with the change of Tc...

Bifurcations of transition states: Morse bifurcations

International Nuclear Information System (INIS)

MacKay, R S; Strub, D C

2014-01-01

A transition state for a Hamiltonian system is a closed, invariant, oriented, codimension-2 submanifold of an energy level that can be spanned by two compact codimension-1 surfaces of unidirectional flux whose union, called a dividing surface, locally separates the energy level into two components and has no local recrossings. For this to happen robustly to all smooth perturbations, the transition state must be normally hyperbolic. The dividing surface then has locally minimal geometric flux through it, giving an upper bound on the rate of transport in either direction. Transition states diffeomorphic to S 2m−3 are known to exist for energies just above any index-1 critical point of a Hamiltonian of m degrees of freedom, with dividing surfaces S 2m−2 . The question addressed here is what qualitative changes in the transition state, and consequently the dividing surface, may occur as the energy or other parameters are varied? We find that there is a class of systems for which the transition state becomes singular and then regains normal hyperbolicity with a change in diffeomorphism class. These are Morse bifurcations. Various examples are considered. Firstly, some simple examples in which transition states connect or disconnect, and the dividing surface may become a torus or other. Then, we show how sequences of Morse bifurcations producing various interesting forms of transition state and dividing surface are present in reacting systems, by considering a hypothetical class of bimolecular reactions in gas phase. (paper)

Gamma transitions between compound states in spherical nuclei

International Nuclear Information System (INIS)

Kadmenskij, S.G.; Markushev, V.P.; Furman, V.I.

1980-01-01

Average values of the reduced γ widths and their dispersions are investigated, basing on the Wigner statistical matrix method, for γ transitions from a compound state c into a less-energy excited state f of an arbitrary complexity in spherical nuclei. It is shown that in all the cases of practical interest the Porter-Thomas distribution is valid for the γ widths. It is found that in the γ transitions between compound states c and c' with Esub(γ) <= 2 MeV the dominating role is played by the M1 transitions due to the main multiquasiparticle states of c, and by the E1 transitions, due to small components of the state c. In framework of the existent theoretical schemes it is shown that the strength functions of the M1 and E1 transitions between the compound states with Esub(γ) <2 MeV are close. It is deduced thet the variant of the M1 transitions is preferable in view of the experimental results on the (n, γα) reactions induced by thermal and resonance neutrons

Evolution of ground-state wave function in CeCoIn5 upon Cd or Sn doping

Science.gov (United States)

Chen, K.; Strigari, F.; Sundermann, M.; Hu, Z.; Fisk, Z.; Bauer, E. D.; Rosa, P. F. S.; Sarrao, J. L.; Thompson, J. D.; Herrero-Martin, J.; Pellegrin, E.; Betto, D.; Kummer, K.; Tanaka, A.; Wirth, S.; Severing, A.

2018-01-01

We present linear polarization-dependent soft-x-ray absorption spectroscopy data at the Ce M4 ,5 edges of Cd- and Sn-doped CeCoIn5. The 4 f ground-state wave functions have been determined for their superconducting, antiferromagnetic, and paramagnetic ground states. The absence of changes in the wave functions in CeCo (In1-xCdx) 5 suggests that the 4 f -conduction-electron (c f ) hybridization is not affected by global Cd doping, thus supporting the interpretation of magnetic droplets nucleating long-range magnetic order. This is contrasted by changes in the wave function due to Sn substitution. Increasing Sn in CeCo (In1-ySny) 5 compresses the 4 f orbitals into the tetragonal plane of these materials, suggesting enhanced c f hybridization with the in-plane In(1) atoms and a homogeneous altering of the electronic structure. As these experiments show, the 4 f wave functions are a very sensitive probe of small changes in the hybridization of 4 f and conduction electrons, even conveying information about direction dependencies.

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

Electric-Field-Driven Dual Vacancies Evolution in Ultrathin Nanosheets Realizing Reversible Semiconductor to Half-Metal Transition.

Science.gov (United States)

Lyu, Mengjie; Liu, Youwen; Zhi, Yuduo; Xiao, Chong; Gu, Bingchuan; Hua, Xuemin; Fan, Shaojuan; Lin, Yue; Bai, Wei; Tong, Wei; Zou, Youming; Pan, Bicai; Ye, Bangjiao; Xie, Yi

2015-12-02

Fabricating a flexible room-temperature ferromagnetic resistive-switching random access memory (RRAM) device is of fundamental importance to integrate nonvolatile memory and spintronics both in theory and practice for modern information technology and has the potential to bring about revolutionary new foldable information-storage devices. Here, we show that a relatively low operating voltage (+1.4 V/-1.5 V, the corresponding electric field is around 20,000 V/cm) drives the dual vacancies evolution in ultrathin SnO2 nanosheets at room temperature, which causes the reversible transition between semiconductor and half-metal, accompanyied by an abrupt conductivity change up to 10(3) times, exhibiting room-temperature ferromagnetism in two resistance states. Positron annihilation spectroscopy and electron spin resonance results show that the Sn/O dual vacancies in the ultrathin SnO2 nanosheets evolve to isolated Sn vacancy under electric field, accounting for the switching behavior of SnO2 ultrathin nanosheets; on the other hand, the different defect types correspond to different conduction natures, realizing the transition between semiconductor and half-metal. Our result represents a crucial step to create new a information-storage device realizing the reversible transition between semiconductor and half-metal with flexibility and room-temperature ferromagnetism at low energy consumption. The as-obtained half-metal in the low-resistance state broadens the application of the device in spintronics and the semiconductor to half-metal transition on the basis of defects evolution and also opens up a new avenue for exploring random access memory mechanisms and finding new half-metals for spintronics.

High-field magnetostriction in CeNiSn{sub 1-x}Ge{sub x} (0<=x<=1) strongly correlated systems

Energy Technology Data Exchange (ETDEWEB)

Moral, A. del, E-mail: delmoral@unizar.e [Laboratorio de Magnetismo de Solidos, Departamento de Fisica de Materia Condensada and ICMA, Universidad de Zaragoza and CSIC, 50009 Zaragoza (Spain); Fuente, C. de la [Laboratorio de Magnetismo de Solidos, Departamento de Fisica de Materia Condensada and ICMA, Universidad de Zaragoza and CSIC, 50009 Zaragoza (Spain)

2010-05-15

Magnetization (down to 1.8 K and up to 9 T) and magnetostriction (down to 4.2 K and up to 30 T) measurements have been performed in the series of polycrystalline intermetallics CeNiSn{sub 1-x}Ge{sub x} (0<=x<=1), which show a crossover from Kondo-lattice to fluctuating valence behaviors with x increase. Magnetostriction observed can be denominated as 'colossal' for a paramagnet (up to 0.68% at 150 K and 30 T), with no sign of saturation. Field, H, induced metamagnetic transitions associated to a change in Ce valence are observed. Three kinds of analysis of magnetostriction have been performed to ascertain the magnetostriction origin. At relatively low field and low temperatures these systems follow well the standard theory of magnetostriction (STM), revealing single-ion crystal field and exchange origins, and a determination of the alpha-symmetry microscopic magnetoelastic parameters have been performed. The valence transition is well explained in terms of the interconfigurational model, which needs an extension up to power H{sup 4}. Application of the scaling (thermodynamics corresponding low states) allows the obtainment of the Grueneisen constant, which increases with x. Needed elastic constants measurements are also reported.

Study on introduction of SN transition type FCL into looped distribution system

International Nuclear Information System (INIS)

Kameda, Hideyuki; Uemura, Satoshi; Ichinose, Ataru

2012-01-01

A large amount of distributed generations such as PV will be introduced into the future Japanese distribution systems. Although distribution systems are presently operated under radial configuration and are terminated with loads, the connection of the distributed generations may cause some problems such as the occurrence of reverse power, the sensitivity decrease of the protection relays, and the voltage rise at the ends. It is assumed that a distribution system is looped in a large city to aim at the improvement of the service reliability under the situation mentioned above. However, a countermeasure against the increase of short-circuit current may be necessary in a looped system. We think that the installation of the SN transition type superconducting fault current limiter (FCL) is effective as a measure against the increase of short-circuit capacity, so we have proposed an effective arrangement of the FCLs into a radial distribution system and the method of setting the parameters. In this paper, a new introduction of FCLs is proposed, that is the way to clear a short-circuit fault within a looped system by the protection relay and the loop switch (LS). To achieve this purpose, the FCL needs to reduce the current through the LS below the rated current of the LS. And we propose the best arrangement to achieve the purpose, and the method of setting the parameters of a SN transition type FCL. Our proposal may bring the flexibility of composing any system configuration.

Controlled synthesis of the antiperovskite oxide superconductor Sr3‑x SnO

Science.gov (United States)

Hausmann, J. N.; Oudah, M.; Ikeda, A.; Yonezawa, S.; Maeno, Y.

2018-05-01

A large variety of perovskite oxide superconductors are known, including some of the most prominent high-temperature and unconventional superconductors. However, superconductivity among the oxidation state inverted material class, the antiperovskite oxides, was recently reported for the first time. In this superconductor, Sr3‑x SnO, the unconventional ionic state Sn4‑ is realized and possible unconventional superconductivity due to a band inversion has been discussed. Here, we discuss an improved facile synthesis method, making it possible to control the strontium deficiency in Sr3‑x SnO. Additionally, a synthesis method above the melting point of Sr3SnO is presented. We show temperature dependence of magnetization and electrical resistivity for superconducting strontium deficient Sr3‑x SnO (T c ∼ 5 K) and for Sr3SnO without a superconducting transition in alternating current susceptibility down to 0.15 K. Further, we reveal a significant effect of strontium raw material purity on the superconductivity and achieve substantially increased M/M Meissner (∼1) compared to the highest value reported so far. More detailed characterizations utilizing powder x-ray diffraction and energy-dispersive x-ray spectroscopy show that a minor cubic phase, previously suggested to be another Sr3‑x SnO phase with a slightly larger lattice parameter, is SrO. The improved characterization and controlled synthesis reported herein enable detailed investigations on the superconducting nature and its dependency on the strontium deficiency in Sr3‑x SnO.

Structure of ground status in magic nuclei and description of their electric transition probabilities

International Nuclear Information System (INIS)

Savane, Y.Sy.

1996-11-01

The structure of the low-lying states in the even-even semi-magic nuclei ( 106-114 50 Sn) and the reduced transition probabilities B(E2, 6 + 1 → 4 = 1 ) for E2-transition have been investigated in the frame of the quasiparticle-phonon nuclear model. The model wave function includes a quasiparticle + two phonons components. It is shown that the small values of the transitions are connected with the non collective structure of the states. The calculated values are in agreement with the observed property of decreasing of the transition with increasing of mass number. (author). 16 refs, 6 tabs

Scintillation and optical properties of Sn-doped Ga2O3 single crystals

Science.gov (United States)

Usui, Yuki; Nakauchi, Daisuke; Kawano, Naoki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

2018-06-01

Sn-doped Ga2O3 single crystals were synthesized by the Floating Zone (FZ) method. In photoluminescence (PL) under the excitation wavelength of 280 nm, we observed two types of luminescence: (1) defect luminescence due to recombination of the donor/acceptor pairs which appears at 430 nm and (2) the nsnp-ns2 transitions of Sn2+ which appear at 530 nm. The PL and scintillation decay time curves of the Sn-doped samples were approximated by a sum of exponential decay functions. The faster two components were ascribed to the defect luminescence, and the slowest component was owing to the nsnp-ns2 transitions. In the pulse height spectrum measurements under 241Am α-rays irradiation, all the Sn-doped Ga2O3 samples were confirmed to show a full energy absorption peak but the undoped one. Among the present samples, the 1% Sn-doped sample exhibited the highest scintillation light yield (1,500 ± 150 ph/5.5 MeV-α).

A cosmographic analysis of the transition to acceleration using SN-Ia and BAO

Energy Technology Data Exchange (ETDEWEB)

Muthukrishna, Daniel; Parkinson, David, E-mail: d.muthukrishna@uq.edu.au, E-mail: d.parkinson@uq.edu.au [School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072 (Australia)

2016-11-01

We explore the distance-redshift relation using a cosmographic methodology, and show how the cosmographic parameters can be used to determine the redshift of transition from deceleration to acceleration. Such a transition at a low redshift occupies only a small region of the available parameter space, and the prior assumption of an early period of deceleration can significantly change the posterior constraints. We use available type Ia Supernovae (SN-Ia) and Baryon Acoustic Oscillation (BAO) data sets to determine the cosmographic deceleration q {sub 0}, jerk j {sub 0}, snap s {sub 0} and lerk l {sub 0} parameters. The parameters are consistent with the ΛCDM model for a flat universe within 2-sigma. We derive constraints on the redshift of transition from deceleration to acceleration for the different expansions, and find z {sub acc} > 0.14 at 95% confidence in the most conservative case.

Calibration of Sn-119 isomer shift using ab initio wave function methods

NARCIS (Netherlands)

Kurian, Reshmi; Filatov, Michael

2009-01-01

The isomer shift for the 23.87 keV M1 resonant transition in the Sn-119 nucleus is calibrated with the help of ab initio calculations. The calibration constant alpha(Sn-119) obtained from Hartree-Fock (HF) calculations (alpha(HF)(Sn-119)=(0.081 +/- 0.002)a(0)(-3) mm/s) and from second-order

Second-order phase transition in PbO and SnO at high pressure: Implications for the litharge-massicot phase transformation

Science.gov (United States)

Adams, David M.; Christy, Andrew G.; Haines, Julian; Clark, Simon M.

1992-11-01

We have studied the structural behavior of PbO at high pressure by powder neturon diffraction in a McWhan cell, and by energy-dispersive powder x-ray diffraction and Raman spectroscopy in a diamond anvil cell. A phase (γ-PbO) occurs at room temperature between ~0.7 and ~2.5 GPa pressure, between the stability fields of litharge (phase is related to litharge by a reversible second-order transition. We infer that this is associated with the collapse of the eu acoustic mode. Unit-cell data at 1.6 GPa are Pm21n, a=4.027(3) Å, b=3.950(3) Å, c=4.767(4) Å, and Z=2. The pressure evolution of the spontaneous strain follows a simple Landau model. There are four distinct solid-state transformation paths between litharge and massicot that maintain the known topotactic relationship between the phases, maintain the translational symmetry common to both, and make use of continuous transitions between group-subgroup related structural intermediates. Both the γ phase and the modulated low-temperature phase of PbO are closely related to one step on one of these paths. Although there is evidence to suggest that the intermediate states do have a transient existence, several paths appear to be utilized. A transition to a γ-like phase also occurs in SnO, at 2.5 GPa, although there is no evidence of a massicotlike polymorph of this compound. The orthorhombic phase is stable to at least 7.5 GPa.

Theoretical expression of the internal conversion coefficient of a M1 transition between two atomic states

International Nuclear Information System (INIS)

Attallah, F.; Chemin, J.F.; Scheurer, J.N.; Karpeshin, F.; Harston, M.

1997-01-01

We have established a general relation for the expression of the internal conversion of an M 1 transition a 1s electronic state to an empty ns electronic bound state. Under the hypothesis that the density of the electron level ρ n satisfies the condition ρ n Γ >> 1 (where Γ is the total width of the excited atomic state) a calculation in the first order gives a relation for the internal conversion coefficient.This relation shows that the internal conversion coefficient takes a resonant character when the nuclear energy transition is smaller than the binding energy of the 1s electron. An application of this relation to an M 1 transition in the case of the ion 125 T e with a charge state Q = 45 and an 1s electron binding energy E B 45 = 35.581 KeV gives the value for the internal conversion coefficient R = 5.7

Term structure of 4d-electron configurations and calculated spectrum in Sn-isonuclear sequence

International Nuclear Information System (INIS)

Al-Rabban, Moza M.

2006-01-01

Theoretical calculations of term structure are carried out for the ground configurations 4d w , of atomic ions in the Sn isonuclear sequence. Atomic computations are performed to give a detailed account of the transitions in Sn +6 to Sn +13 ions. The spectrum is calculated for the most important excited configurations 4p 5 4d n+1 , 4d n-1 4f 1 , and 4d n-1 5p 1 with respect to the ground configuration 4d n , with n=8-1, respectively. The importance of 4p-4d, 4d-4f, and 4d-5p transitions is stressed, as well as the need for the configuration-interaction CI treatment of the Δn=0 transitions. In the region of importance for extreme ultraviolet (EUV) lithography around 13.4nm, the strongest lines were expected to be 4d n -4p 5 4d n+1 and 4d n -4d n-1 4f 1

In-situ investigation of the order-disorder transition in Cu2ZnSnSe4 by optical transmission spectroscopy

Directory of Open Access Journals (Sweden)

Christiane Stroth

2017-02-01

Full Text Available The existence of disorder is one possible reason for the limited performance of kesterite solar cells. Therefore further knowledge of the order-disorder phase transition, of factors which influence the degree of order and of methods to determine this material property is still required. In this study we investigated the order-disorder transition in the kesterite material Cu2ZnSnSe4 by in-situ optical transmission spectroscopy during heat treatments. We show in-situ results for the temperature dependence of the band gap and its tailing properties. The influence of cooling rates on the phase transition was analyzed as well as the ordering kinetics during annealing at a constant temperature. The critical temperature of the phase transition was determined and the existence of a control temperature range is shown, which allows for controlling the degree of order by the cooling rate within this range. Additionally we performed Raman analysis to link Raman spectra to the degree of order in Cu2ZnSnSe4. A correlation between the intensity ratio of A-modes as well as B-/ E- Raman modes and the degree of order was found.

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.

Comparative Analysis of Light-Harvesting Antennae and State Transition in chlorina and cpSRP Mutants1[OPEN

Science.gov (United States)

Wang, Peng

2016-01-01

State transitions in photosynthesis provide for the dynamic allocation of a mobile fraction of light-harvesting complex II (LHCII) to photosystem II (PSII) in state I and to photosystem I (PSI) in state II. In the state I-to-state II transition, LHCII is phosphorylated by STN7 and associates with PSI to favor absorption cross-section of PSI. Here, we used Arabidopsis (Arabidopsis thaliana) mutants with defects in chlorophyll (Chl) b biosynthesis or in the chloroplast signal recognition particle (cpSRP) machinery to study the flexible formation of PS-LHC supercomplexes. Intriguingly, we found that impaired Chl b biosynthesis in chlorina1-2 (ch1-2) led to preferentially stabilized LHCI rather than LHCII, while the contents of both LHCI and LHCII were equally depressed in the cpSRP43-deficient mutant (chaos). In view of recent findings on the modified state transitions in LHCI-deficient mutants (Benson et al., 2015), the ch1-2 and chaos mutants were used to assess the influence of varying LHCI/LHCII antenna size on state transitions. Under state II conditions, LHCII-PSI supercomplexes were not formed in both ch1-2 and chaos plants. LHCII phosphorylation was drastically reduced in ch1-2, and the inactivation of STN7 correlates with the lack of state transitions. In contrast, phosphorylated LHCII in chaos was observed to be exclusively associated with PSII complexes, indicating a lack of mobile LHCII in chaos. Thus, the comparative analysis of ch1-2 and chaos mutants provides new evidence for the flexible organization of LHCs and enhances our understanding of the reversible allocation of LHCII to the two photosystems. PMID:27663408

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.

The Material Properties of CsSnBr3 and CsBr:Sn-1% and Their Potential as Scintillator Detector Material

Science.gov (United States)

2010-03-01

Iodide or Cesium Iodide are the benchmarks for ease of use and quick identification of isotope species. This research aims to explore Cesium Bromide doped...oxidation states of 3+, 4+, 5+ and 6+ were used to identify the Pu pollution in the Rocky Flats area. The identification of the Pu4+ oxidation state...point was causing the normalization of the spectra to be much higher than what it should be. The XANES structures lineup showing the Sn in the CsSnBr3

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.

Topological crystalline insulator PbxSn1-xTe thin films on SrTiO3 (001 with tunable Fermi levels

Directory of Open Access Journals (Sweden)

Hua Guo

2014-05-01

Full Text Available In this letter, we report a systematic study of topological crystalline insulator PbxSn1-xTe (0 < x < 1 thin films grown by molecular beam epitaxy on SrTiO3(001. Two domains of PbxSn1-xTe thin films with intersecting angle of α ≈ 45° were confirmed by reflection high energy diffraction, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy (ARPES. ARPES study of PbxSn1-xTe thin films demonstrated that the Fermi level of PbTe could be tuned by altering the temperature of substrate whereas SnTe cannot. An M-shaped valance band structure was observed only in SnTe but PbTe is in a topological trivial state with a large gap. In addition, co-evaporation of SnTe and PbTe results in an equivalent variation of Pb concentration as well as the Fermi level of PbxSn1-xTe thin films.

Variational transition-state theory

International Nuclear Information System (INIS)

Truhlar, D.G.; Garrett, B.C.

1980-01-01

A general introduction to and some results from studies of a procedure called variational transition-state theory are presented. A fundamental assumption of this theory is that the net rate of forward reaction at equilibrium equals the equilibrium flux in the product direction through the transition state where the transition state is a surface in phase space dividing reactants from products. Classical generalized-transition-state-theory calculations for nine collinear systems are compared to classical trajectory calculations. This new technique should provide useful insight into the successes and failures of the conventional theory and useful quantitative estimates of possible errors on the predictions of conventional transition-state theory. This should also contribute to a more accurate theory now available for the practical calculations of chemical reaction rates and thermochemical and structural interpretations of rate processes

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

Comparison of fluctuating potentials and donor-acceptor pair transitions in a Cu-poor Cu{sub 2}ZnSnS{sub 4} based solar cell

Energy Technology Data Exchange (ETDEWEB)

Teixeira, J. P.; Sousa, R. A.; Sousa, M. G.; Cunha, A. F. da; Leitão, J. P., E-mail: joaquim.leitao@ua.pt [Departamento de Física and I3N, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Fernandes, P. A. [Departamento de Física and I3N, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); Salomé, P. M. P. [INL - International Iberian Nanotechnology Laboratory, Laboratory for Nanostructured Solar Cells (LaNaSC), Av. Mestre José Veiga, 4715-330 Braga (Portugal); González, J. C. [Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, Minas Gerais (Brazil)

2014-10-20

The structure of the electronic energy levels of a single phase Cu{sub 2}ZnSnS{sub 4} film, as confirmed by Raman Scattering and x-ray diffraction, is investigated through a dependence on the excitation power of the photoluminescence (PL). The behavior of the observed asymmetric band, with a peak energy at ∼1.22 eV, is compared with two theoretical models: (i) fluctuating potentials and (ii) donor-acceptor pair transitions. It is shown that the radiative recombination channels in the Cu-poor film are strongly influenced by tail states in the bandgap as a consequence of a heavy doping and compensation levels. The contribution of the PL for the evaluation of secondary phases is also highlighted.

Thermoelectric prospects of chemically deposited PbSe and SnSe thin films

Science.gov (United States)

Nair, P. K.; Martínez, Ana Karen; Rosa García Angelmo, Ana; Barrios Salgado, Enue; Nair, M. T. S.

2018-03-01

Thin films of PbSe of 400-600 nm in thickness, were obtained via chemical deposition from a solution containing lead nitrate, thiourea and selenosufate. SnSe thin films of 90-180 nm in thickness, were also obtained by chemical deposition from a solution containing selenosulfate. Optical and electrical properties of these thin films were significantly altered by heating them in selenium vapor at 300 °C. Thin film PbSe has a bandgap (Eg) of 1.17 eV (direct gap, forbidden transitions), which decreases to 0.77 eV when it has been heated. Its electrical conductivity (σ) is p-type: 0.18 Ω-1 cm-1 (as-prepared), and 6.4 Ω-1 cm-1 when heated. Thin film SnSe is of orthorhombic crystalline structure which remains stable when heated at 300 °C, but its Eg increases from 1.12 eV (indirect) in as-prepared film to 1.5 eV (direct, forbidden transitions) upon heating. Its electrical conductivity is p-type, which increases from 0.3 Ω-1 cm-1 (as-prepared) to 1 Ω-1 cm-1 when heated (without Se-vapor). When SnSe film is heated at 300 °C in the presence of Se-vapor, they transform to SnSe2, with Eg of 1.5 eV (direct, forbidden) with n-type electrical conductivity, 11 Ω-1 cm-1. The Seebeck coefficient for the PbSe films is: +0.55 mV K-1 (as prepared) and +0.275 mV K-1 (heated); for SnSe films it is: +0.3 mV K-1 (as prepared) and +0.20 mV K-1 (heated); and for SnSe2 film, - 0.35 mV K-1. A five-element PbSe-SnSe2-PbSe-SnSe2-PbSe thermoelectric device demonstrated 50 mV for a temperature difference ΔT = 20 °C (2.5 mV K-1). For SnSe-SnSe2-SnSe-SnSe2-SnSe device, the value is 15 mV for ΔT = 20 °C (0.75 mV K-1). Prospect of these thin films in thermoelectric devices of hybrid materials, in which the coatings may be applied on distinct substrate and geometries is attractive.

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.

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.

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

Defect study of Cu2ZnSn(SxSe1-x)4 thin film absorbers using photoluminescence and modulated surface photovoltage spectroscopy

Science.gov (United States)

Lin, Xianzhong; Ennaoui, Ahmed; Levcenko, Sergiu; Dittrich, Thomas; Kavalakkatt, Jaison; Kretzschmar, Steffen; Unold, Thomas; Lux-Steiner, Martha Ch.

2015-01-01

Defect states in Cu2ZnSn(SxSe1-x)4 thin films with x = 0.28, 0.36, and 1 were studied by combining photoluminescence (PL) and modulated surface photovoltage (SPV) spectroscopy. A single broad band emission in the PL spectra was observed and can be related to quasi-donor-acceptor pair transitions. The analysis of the temperature dependent quenching of the PL band (x = 0.28, 0.36, and 1) and SPV (x = 0.28) signals resulted in activation energies below 150 meV for PL and about 90 and 300 meV for SPV. Possible intrinsic point defects that might be associated with these observed activation energies are discussed.

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

0+ analogue state in 118Sb from 117Sn(p,nγ) reaction

International Nuclear Information System (INIS)

Pal, J.; Dey, C.C.; Bose, S.; Sinha, B.K.; Chatterjee, M.B.; Mahapatra, D.P.

1996-01-01

The analogue of the 0 + ground state in 118 Sn has been observed in the compound nucleus 118 Sb through 117 Sn(p,nγ) 117 Sb reaction. The neutron decays of this analogue resonance have been studied from the deexciting γ-rays of the residual nucleus 117 Sb. From off resonance excitation functions, spin assignments have been made to states in 117 Sb, on the basis of Hauser-Feshbach formalism. The resonance parameters of the isobaric analogue resonance have been determined, including the total, proton and neutron decay widths. (orig.)

Wavelength-tuned light emission via modifying the band edge symmetry: Doped SnO2 as an example

KAUST Repository

Zhou, Hang

2014-03-27

We report the observation of ultraviolet photoluminescence and electroluminescence in indium-doped SnO2 thin films with modified "forbidden" bandgap. With increasing indium concentration in SnO 2, dominant visible light emission evolves into the ultraviolet regime in photoluminescence. Hybrid functional first-principles calculations demonstrate that the complex of indium dopant and oxygen vacancy breaks "forbidden" band gap to form allowed transition states. Furthermore, undoped and 10% indium-doped SnO2 layers are synthesized on p-type GaN substrates to obtain SnO2-based heterojunction light-emitting diodes. A dominant visible emission band is observed in the undoped SnO 2-based heterojunction, whereas strong near-ultraviolet emission peak at 398 nm is observed in the indium-doped SnO2-based heterojunction. Our results demonstrate an unprecedented doping-based approach toward tailoring the symmetry of band edge states and recovering ultraviolet light emission in wide-bandgap oxides. © 2014 American Chemical Society.

New insights into the structure, chemistry, and properties of Cu.sub.4./sub.SnS.sub.4./sub.

Czech Academy of Sciences Publication Activity Database

Choudhury, A.; Mohapatra, S.; Asl, H.Y.; Lee, S.H.; Hor, Y.S.; Medvedeva, J.E.; McClane, D.L.; Hilmas, G.E.; McGuire, M.A.; May, A.H.; Wang, H.; Dash, S.; Welton, A.; Boolchand, P.; Devlin, K.P.; Aitken, J.; Herbst-Irmer, R.; Petříček, Václav

2017-01-01

Roč. 253, Sep (2017), s. 192-201 ISSN 0022-4596 Institutional support: RVO:68378271 Keywords : Cu 4 SnS 4 * phase transition * crystal structure * electronic properties * thermoelectrics * band structure * 119-Sn Mössbauer Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.299, year: 2016

Stability and magnetic properties of SnSe monolayer doped by transition metal atom (Mn, Fe, and Co): a first-principles study

Science.gov (United States)

Tang, Chao; Li, Qinwen; Zhang, Chunxiao; He, Chaoyu; Li, Jin; Ouyang, Tao; Li, Hongxing; Zhong, Jianxin

2018-06-01

Two dimensional (2D) tin selenium (SnSe) is an intriguing material with desired thermal and electric properties in nanoelectronics. In this paper, we carry on a density functional theory study on the stability and dilute magnetism of the 3d TM (Mn, Fe, and Co) doped 2D SnSe. Both the adsorption and substitution are in consideration here. We find that all the defects are electrically active and the cation substitutional doping (TM@Sn) is energetically favorable. The TM@Sn prefers to act as accepters and exhibits high-spin state with nonzero magnetic moment. The magnetic moment is mainly contributed by the spin-polarized charge density of the TM impurities. The magnetism is determined by the arrangement of the TM-3d orbitals, which is the result of the crystal field splitting and spin exchange splitting under specific symmetry. The magnetic and electronic properties of the TM@Sn are effectively modulated by external electric field (Eext) and charge doping. The Eext shifts the TM impurities relative to the SnSe host and then modifies the crystal field splitting. In particular, the magnetic moment is sensitive to the Eext in the Fe@Sn because the Eext induces distinct structure transformation. Based on the formation energy, doping electrons is a viable way to modulate the magnetic moment of TM@Sn. Doping electrons shift the 3d states towards low energy level, which induces the occupation of more 3d states and then the reduction of magnetism. These results render SnSe monolayer a promising 2D material for applications in future spintronics.

Magnetism tuned by the charge states of defects in bulk C-doped SnO2 materials.

Science.gov (United States)

Lu, Ying-Bo; Ling, Z C; Cong, Wei-Yan; Zhang, Peng

2015-10-21

To analyze the controversial conclusions on the magnetism of C-doped SnO2 (SnO2:C) bulk materials between theoretical calculations and experimental observations, we propose the critical role of the charge states of defects in the geometric structures and magnetism, and carry out a series of first principle calculations. By changing the charge states, we can influence Bader charge distributions and atomic orbital occupancies in bulk SnO2:C systems, which consequently conduct magnetism. In all charged SnO2:C supercells, C-2px/py/pz electron occupancies are significantly changed by the charge self-regulation, and thus they make the C-2p orbitals spin polarized, which contribute to the dominant magnetic moment of the system. When the concentration of C dopant in the SnO2 supercell increases, the charge redistribution assigns extra electrons averagely to each dopant, and thus effectively modulates the magnetism. These findings provide an experimentally viable way for controlling the magnetism in these systems.

SnSe2 Two Dimensional Anodes for Advanced Sodium Ion Batteries

KAUST Repository

Zhang, Fan

2017-05-30

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries (LIBs) for large-scale renewable energy storage units due to the abundance of sodium resource and its low cost. However, the development of anode materials for SIBs to date has been mainly limited to some traditional anodes for LIBs, such as carbonaceous materials. SnSe2 is a member of two dimensional layered transition metal dichalcogenide (TMD) family, which has been predicted to have high theoretical capacity as anode material for sodium ion batteries (756 mAh g-1), thanks to its layered crystal structure. Yet, there have been no studies on using SnSe2 as Na ion battery anode. In this thesis, we developed a simple synthesis method to prepare pure SnSe2 nanosheets, employing N2 saturated NaHSe solution as a new selenium source. The SnSe2 2D sheets achieve theoretical capacity during the first cycle, and a stable and reversible specific capacity of 515 mAh g-1 at 0.1 A g-1 after 100 cycles, with excellent rate performance. Among all of the reported transition metal selenides, our SnSe2 sample has the highest reversible capacity and the best rate performances. A combination of ex-situ high resolution transmission electron microscopy (HRTEM) and X-ray diffraction was used to study the mechanism of sodiation and desodiation process in this SnSe2, and to understand the reason for the excellent results that we have obtained. The analysis indicate that a combination of conversion and alloying reactions take place with SnSe2 anodes during battery operation, which helps to explain the high capacity of SnSe2 anodes for SIBs compared to other binary selenides. Density functional theory was used to elucidate the volume changes taking place in this important 2D material.

Annealing of RF-magnetron sputtered SnS{sub 2} precursors as a new route for single phase SnS thin films

Energy Technology Data Exchange (ETDEWEB)

Sousa, M.G., E-mail: martasousa@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Cunha, A.F. da, E-mail: antonio.cunha@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Fernandes, P.A., E-mail: pafernandes@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto (Portugal)

2014-04-01

then correlated with the annealing temperature. Scanning electron microscopy studies revealed that the SnS films exhibit small grain structure and the film surface is rough. Optical measurements were performed, from which the band gap energies were estimated. These studies show that the direct absorption transitions of SnS are at 1.68 eV and 1.41 eV for annealing in graphite box with and without elemental sulphur evaporation, respectively. For the indirect transition the values varied from 1.49 eV to 1.37 eV. The results of this work show that the third approach is better suited to produce single phase SnS films. However, a finer tunning of the duration of the high temperature plateau of the annealing profile is required in order to eliminate the β-Sn top layer.

First-principles prediction of shape memory behavior and ferrimagnetism in Mn2NiSn

International Nuclear Information System (INIS)

Paul, Souvik; Ghosh, Subhradip

2011-01-01

Using first-principles density functional theory, we show that, in Mn 2 NiSn, an energy lowering phase transition from the cubic to tetragonal phase occurs which indicates a martensitic phase transition. This structural phase transition is nearly volume-conserving, implying that this alloy can exhibit shape memory behavior. The magnetic ground state is a ferrimagnetic one with antiparallel Mn spin moments. The calculated moments with different electronic structure methods in the cubic phase compare well with each other but differ from the experimental values by more than 1 μ B . The reason behind this discrepancy is explored by considering antisite disorder in our calculations, which indicates that the site ordering in this alloy can be quite complex.

Mechanisms of regulation of SNF1/AMPK/SnRK1 protein kinases

Science.gov (United States)

Crozet, Pierre; Margalha, Leonor; Confraria, Ana; Rodrigues, Américo; Martinho, Cláudia; Adamo, Mattia; Elias, Carlos A.; Baena-González, Elena

2014-01-01

The SNF1 (sucrose non-fermenting 1)-related protein kinases 1 (SnRKs1) are the plant orthologs of the budding yeast SNF1 and mammalian AMPK (AMP-activated protein kinase). These evolutionarily conserved kinases are metabolic sensors that undergo activation in response to declining energy levels. Upon activation, SNF1/AMPK/SnRK1 kinases trigger a vast transcriptional and metabolic reprograming that restores energy homeostasis and promotes tolerance to adverse conditions, partly through an induction of catabolic processes and a general repression of anabolism. These kinases typically function as a heterotrimeric complex composed of two regulatory subunits, β and γ, and an α-catalytic subunit, which requires phosphorylation of a conserved activation loop residue for activity. Additionally, SNF1/AMPK/SnRK1 kinases are controlled by multiple mechanisms that have an impact on kinase activity, stability, and/or subcellular localization. Here we will review current knowledge on the regulation of SNF1/AMPK/SnRK1 by upstream components, post-translational modifications, various metabolites, hormones, and others, in an attempt to highlight both the commonalities of these essential eukaryotic kinases and the divergences that have evolved to cope with the particularities of each one of these systems. PMID:24904600

Vacancy-induced brittle to ductile transition of W-M co-doped Al3Ti (M=Si, Ge, Sn and Pb).

Science.gov (United States)

Zhu, Mingke; Wu, Ping; Li, Qiulin; Xu, Ben

2017-10-25

We investigated the effect of vacancy formation on brittle (D0 22 ) to ductile (L1 2 -like) transition in Al 3 Ti using DFT calculations. The well-known pseudogap on the density of states of Al 3 Ti migrates towards its Fermi level from far above, via a W - M co-doping strategy, where M is Si, Ge, Sn or Pb respectively. In particular, by a W - M co-doping the underline electronic structure of the pseudogap approaches an octahedral (L1 2 : t 2g , e g ) from the tetragonal (D0 22 : e g , b 2g , a 1g , b 1g ) crystal field. Our calculations demonstrated that (1) a W-doping is responsible for the close up of the energy gap between a 1g and b 1g so that they tend to merge into an e g symmetry, and (2) all M-doping lead to a narrower gap between e g and b 2g (moving towards a t 2g symmetry). Thus, a brittle to ductile transition in Al 3 Ti is possible by adopting this W - M co-doping strategy. We further recommend the use of W-Pb co-doped Al 3 Ti to replace the less anodic Al electrode in Al-battery, due to its improved ductility and high Al diffusivity. Finally this study opens a new field in physics to tailor mechanical properties by manipulating electron energy level(s) towards higher symmetry via vacancy optimization.

Characterisation of the antiferromagnetic transition of Cu2FeSnS4, the synthetic analogue of stannite

Science.gov (United States)

Caneschi, A.; Cipriani, C.; di Benedetto, F.; Sessoli, R.

2003-04-01

Magnetisation measurements between 260 and 1.9K were performed on the synthetic analogue of stannite, Cu_2FeSnS_4, tetragonal Ioverline{4}2m. Fe(II) ions, in the high spin S=2 configuration for tetrahedral coordination, are responsible for the high temperature paramagnetism. In agreement with Bernardini et al. (2000), an antiferromagnetic transition was observed, lowering temperature below 8K. Refined measurements evidenced a T_N=6.1K for the Néel temperature. In spite of a small difference, observed in the behaviour between the zero-field cooled and the field cooled curves, which suggests the possible presence of a spin-glass phase, the AC measurements did not provide evidence of dependence of the magnetic susceptibility on frequency, as expected in spin-glass systems. On the basis of the experimental data, in agreement with the existent literature (Fries et al., 1997), a collinear antiferromagnetic structure should be preferred. The Fe ions, in fact, are distributed in two sublattices obtained by magnetic differentiation of the symmetry equivalent (0,0,0) and (frac{1}{2}frac{1}{2}frac{1}{2}) Fe positions (wyckoff: 2a). The low value for the Nèel temperature, as compared e.g. to the room-temperature antiferromagnet chalcopyrite (CuFeS_2), very close in composition and structure to stannite, is to be related to the increased distance between the Fe ions (˜6.6Å). This weak interaction is not detected in natural samples, where diamagnetic Zn(II) replace paramagnetic Fe(II), thus increasing the mean Fe-Fe distance. Fries, T., Shapira, Y., Palacio, F., Moròn, M.C., McIntyre, G.J., Kershaw, R., Wold, A. and McNiff, E.J. Jr. (1997): Mangetic ordering of the antiferromagnet Cu_2MnSnS_4 from magnetisation and neutron-scattering measurements. Phys. Rev. B, 6(9), 5424-5431 Bernardini, G.P., Borrini, D., Caneschi, A. Di Benedetto, F., Gatteschi, D., Ristori, S. and Romanelli, M. (2000): EPR and SQUID magnetometry study of Cu_2FeSnS_4 (stannite) and Cu_2ZnSnS_4 (kesterite

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

Structural stability of ternary C22–Zr6X2Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and C22–Zr6Sn2T′ (T′=Fe, Co, Ni, Cu) compounds

International Nuclear Information System (INIS)

Colinet, Catherine; Crivello, Jean-Claude; Tedenac, Jean-Claude

2013-01-01

The crystal and electronic structures, and the thermodynamic properties of Zr 6 X 2 Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and Zr 6 Sn 2 T′ (T′=Fe, Co, Ni, Cu) ternary compounds in the Fe 2 P-type structure have been investigated by means of first principle calculations. The calculated structural parameters are in good agreement with the experimental data. The total electronic densities of states as well as the Bader charges of the atoms have been computed. Both electronic and size effects allow to explain the stability of the ternary Zr 6 X 2 Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and Zr 6 Sn 2 T′ (T′=Fe, Co, Ni, Cu) compounds. - Graphical abstract: Valence charge electronic localization function (ELF) calculated for Zr 6 Sb 2 Co compound. Display Omitted - Highlights: • Structural stability of Zr 6 X 2 T′ compounds (X: p element, T′: late transition metal) in the Fe 2 P-type structure. • First principles calculation of lattice parameters and enthalpies of formation. • Electronic densities of state in the series Zr 6 Sn 2 T′ (T′=Fe, Co, Ni, Cu). • Electronic densities of state in the series Zr 6 X 2 Co (X=Al, Ga, Sn, As, Sb, Bi, Te)

Theoretical and experimental study of α-Sn deposited on CdTe(001)

International Nuclear Information System (INIS)

Gomez, J.A.; Guenzburger, D.; Ellis, D.E.; Hu, M.Y.; Baggio-Saitovitc, E.M.; Passamani, E.C.; Alp, E.E.

2003-01-01

Gray tin films enriched by over 95% 119 Sn and grown by molecular beam epitaxy on CdTe(001) wafers are characterized by inelastic nuclear resonance spectroscopy and investigated theoretically by embedded-cluster density-functional theory methods. Experimental tin phonon densities of states are obtained via analysis of resonant scattering of the 23.88-keV nuclear transition, making use of a high-resolution spectrometer at the Advanced Photon Source. Conventional Moessbauer spectroscopy is used in the scattering mode to determine hyperfine parameters of the α-Sn phase and, after thermal treatment, the β phase. Electronic structure in the vicinity of Sn-Cd and Sn-Te interfaces is calculated in order to determine local charge transfer and changes in hyperfine parameters for 119 Sn atoms in the interface region. Although, due to sample thickness, both experiments reveal properties essentially of the bulk, the calculations allow investigation of surface and interface regions at an atomic level, thus providing complementary information. Effects of interlayer relaxation are explored.

Core-level photoelectron study of Si(1 1 1) sq root 7x sq root 3-(Pb, Sn) surface

CERN Document Server

Soda, K; Takada, T; Yoshimoto, O; Kato, M; Yagi, S; Morita, K; Kamada, M

2003-01-01

The Sn 4d and Pb 5d core-level photoelectron spectra have been studied in order to clarify their bonding properties and atomic arrangement on a Si(1 1 1) sq root 7x sq root 3-(Pb, Sn) surface, which is formed by the coadsorption of 0.4 ML Pb and 0.4 ML Sn and shows two kinds of bright spots in the scanning tunneling microscopic (STM) images: (A) those aligned zigzag on the T sub 1 site and (B) those on the T sub 1 and H sub 3 sites along the [1 1 -2] direction. The Pb 5d spectrum shows a single spin-orbit-split feature with weak tailing towards the high binding energy side, while the Sn 4d spectrum exhibits shoulder structures at the high binding energy side of the main peaks. This definitely indicates at least two different Sn-Si bonds or inequivalent Sn adsorbing sites and single bond or site for Pb. Thus the spots A at the T sub 1 site and those B at the T sub 1 and H sub 3 sites in the STM images are ascribed to Pb and Sn adatoms, respectively. The formation process of this surface will be also discussed ...

Variational Transition State Theory

Energy Technology Data Exchange (ETDEWEB)

Truhlar, Donald G. [Univ. of Minnesota, Minneapolis, MN (United States)

2016-09-29

This is the final report on a project involving the development and applications of variational transition state theory. This project involved the development of variational transition state theory for gas-phase reactions, including optimized multidimensional tunneling contributions and the application of this theory to gas-phase reactions with a special emphasis on developing reaction rate theory in directions that are important for applications to combustion. The development of variational transition state theory with optimized multidimensional tunneling as a useful computational tool for combustion kinetics involved eight objectives.

The effect of electron and hole doping on the thermoelectric properties of shandite-type Co3Sn2S2

Science.gov (United States)

Mangelis, Panagiotis; Vaqueiro, Paz; Jumas, Jean-Claude; da Silva, Ivan; Smith, Ronald I.; Powell, Anthony V.

2017-07-01

Electron and hole doping in Co3Sn2S2, through chemical substitution of cobalt by the neighbouring elements, nickel and iron, affects both the structure and thermoelectric properties. Electron doping to form Co3-xNixSn2S2 (0≤x≤3) results in an expansion of the kagome layer and materials become increasingly metallic as cobalt is substituted. Conversely, hole doping in Co3-xFexSn2S2 (0≤x≤0.6) leads to a transition from metallic to n-type semiconducting behaviour at x=0.5. Iron substitution induces a small increase in the separation between the kagome layers and improves the thermoelectric performance. Neutron diffraction data reveal that substitution occurs at the Co 9(d) site in a disordered fashion. Mössbauer spectroscopy reveals two iron environments with very different isomer shifts, which may be indicative of a mixed-valence state, while Sn exhibits an oxidation state close to zero in both series. Co2.6Fe0.4Sn2S2 exhibits a maximum figure-of-merit, ZT=0.2 at 523 K while Co2.4Fe0.6Sn2S2 reaches a power factor of 10.3 μW cm-1 K-2 close to room temperature.

Electrochemical oxidation of methanol on Pt/(RuxSn1-xO2 nanocatalyst

Directory of Open Access Journals (Sweden)

Krstajić Mila N.

2013-01-01

Full Text Available The Ru-doped SnO2 powder, (RuxSn1-xO2, with the Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass% loading. The (RuxSn1-xO2 support and Pt/(RuxSn1-xO2 catalyst were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM. (RuxSn1-xO2 was found to be two-phase material consisting of probably solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-xO2 indicated good conductivity of the sup-port and displayed usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-xO2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-xO2 starts at less positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of Pt/(RuxSn1-xO2 catalyst compared to PtRu/C, but also a greater loss in the current density over time. Potentiodynamic stability test of the catalysts revealed that deactivation of the Pt/(RuxSn1-xO2 and Pt/C was primarily caused by the poisoning of Pt surface by the methanol oxidation residues, which mostly occurred during the first potential cycle. In the case of PtRu/C the poisoning of the surface was minor and deactivation was caused by the PtRu surface area loss. [Projekat Ministarstva nauke Republike Srbije, br. ON-172054

A global view of the phase transitions of SnO2 in rechargeable batteries based on results of high throughput calculations

KAUST Repository

Cheng, Yingchun; Nie, Anmin; Gan, Liyong; Zhang, Qingyun; Schwingenschlö gl, Udo

2015-01-01

Lithium, sodium and magnesium have attracted wide attention as potential ions for rechargeable batteries. The Materials Project database of high throughput first principles calculations is used to investigate the phase transitions of SnO2 during ion

Effect of alloying Mo on mechanical strength and corrosion resistance of Zr-1% Sn-1% Nb-1% Fe alloy

International Nuclear Information System (INIS)

Sugondo

2011-01-01

It had been done research on Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy. The ingot was prepared by means of electrical electrode technique. The chemical analysis was identified by XRF, the metallography examination was perform by an optical microscope, the hardness test was done by Vickers microhardness, and the corrosion test was done in autoclave. The objective of this research were making Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy with Mo concentration; comparing effect of Mo concentration to metal characteristics of Zr-1%Sn-1%Nb-1%Fe which covered microstructure; composition homogeneity, mechanical strength; and corrosion resistance in steam, and determining the optimal Mo concentration in Zr-1%Sn-1%Nb-1%Fe-(x)% Mo alloy for nuclear fuel cladding which had corrosion resistance and high hardness. The results were as follow: The alloying Mo refined grains at concentration in between 0,1%-0,3% and the concentration more than that could coarsened grains. The hardness of the Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was controlled either by the flaw or the dislocation, the intersection of the harder alloying element, the solid solution of the alloying element and the second phase formation of ZrMo 2 . The corrosion rate of the Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was controlled by the second phase of ZrMo 2 . The 0.3% Mo concentration in Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was the best for second phase formation. The Mo concentration in between 0,3-0,5% in Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was good for the second phase formation and the solid solution. (author)

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.

Martensitic transformation and magnetic properties of manganese-rich Ni-Mn-In and Ni-Mn-Sn Heusler alloys

International Nuclear Information System (INIS)

Krenke, T.

2007-01-01

In the present work, the martensitic transition and the magnetic properties of Manganese rich Ni 50 Mn 50-x Sn x and Ni 50 Mn 50-y In y alloys with 5 at%≤x(y)≤25 at% were investigated. Calorimetry, X-ray and neutron diffraction, magnetization, and strain measurements were performed on polycrystalline samples. It was shown that alloys close to the stoichiometric composition Ni 50 Mn 25 Sn 25 and Ni 50 Mn 25 Sn 25 do not exhibit a structural transition on lowering of the temperature, whereas alloys with x≤15 at% Tin and y≤16 at% Indium transform martensitically. The structural transition temperatures increase linearly with decreasing Tin or Indium content. The crystal structures of the low temperature martensite are modulated as well as unmodulated. Alloys with compositions close to stoichiometry are dominated by ferromagnetic interactions, whereas those close to the binary composition Ni 50 Mn 50 order antiferromagnetically. Ferromagnetic order and structural instability coexist in a narrow composition range between 13 at%≤x≤15 at% and 15 at%≤x≤16 at% for Ni 50 Mn 50-x Sn x and Ni 50 Mn 50-y In y respectively. As a consequence, interesting magnetoelastic effects are observed. The Ni 50 Mn 34 In 16 alloy shows a magnetic field-induced structural transition, whereby application of an external magnetic field in the martensitic state stabilizes the high temperature L2 1 structure. Evidence for this was given by neutron diffraction experiments in external magnetic fields. Moreover, the structural transition temperatures of this alloy show large magnetic field dependencies. By use of calorimetry, M(T), and strain measurements, changes in M s up to -11 K/Tesla are observed. Such large values have, until now, not been observed in Heusler alloys. Since during transformation the volume changes reversibly, magnetic field-induced strains of about 0.12 % appear. Additionally, the alloys Ni 50 Mn 35 Sn 15 , Ni 50 Mn 37 Sn 13 , Ni 50 Mn 34 In 16 , Ni 51.5 Mn 33 In

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.

Critical thickness of transition from 2D to 3D growth and peculiarities of quantum dots formation in GexSi1-x/Sn/Si and Ge1-ySny/Si systems

Science.gov (United States)

Lozovoy, Kirill A.; Kokhanenko, Andrey P.; Voitsekhovskii, Alexander V.

2018-03-01

Nowadays using of tin as one of the deposited materials in GeSi/Sn/Si, GeSn/Si and GeSiSn/Si material systems is one of the most topical problems. These materials are very promising for various applications in nanoelectronics and optoelectronics due to possibility of band gap management and synthesis of direct band semiconductors within these systems. However, there is a lack of theoretical investigations devoted to the peculiarities of germanium on silicon growth in the presence of tin. In this paper a new theoretical approach for modeling growth processes of binary and ternary semiconductor compounds during the molecular beam epitaxy in these systems is presented. The established kinetic model based on the general nucleation theory takes into account the change in physical and mechanical parameters, diffusion coefficient and surface energies in the presence of tin. With the help of the developed model the experimentally observed significant decrease in the 2D-3D transition temperatures for GeSiSn/Si system compared to GeSi/Si system is theoretically explained for the first time in the literature. Besides that, the derived expressions allow one to explain the experimentally observed temperature dependencies of the critical thickness, as well as to predict the average size and surface density of quantum dots for different contents and temperatures in growth experiment, that confirms applicability of the model proposed. Moreover, the established model can be easily applied to other material systems in which the Stranski-Krastanow growth mode occurs.

Phase Equilibria in the Bi-In-Sn-Zn System. Thermal Analysis vs. Calculations

Directory of Open Access Journals (Sweden)

Dębski A.

2017-12-01

Full Text Available With the use of the differential thermal analysis (DTA, studies of the phase transitions were conducted for 90 of alloys from the quaternary Bi-In-Sn-Zn system and for the constant ratio of Bi:In and Bi:Sn. The studies were conducted for the alloys prepared from the purity metals (Bi, In, Sn, Zn = 99.999 mas. % by way of melting in a graphite crucible in a glove-box filled with Ar, in which the impurities level was less than 0.1 ppm. After melting and thorough mixing, the liquid alloys were poured out into a graphite test mold. The phase transition temperature data obtained from the DTA investigations were next confronted with those determined from the calculations based on the binary and ternary optimized thermodynamic parameters available in the literature. It was found that the experimental and the calculated phase transition temperatures were in good agreement.

Thermoelectric properties of chalcogenide based Cu2+xZnSn1−xSe4

Directory of Open Access Journals (Sweden)

Ch. Raju

2013-03-01

Full Text Available Quaternary chalcogenide compounds Cu2+xZnSn1−xSe4 (0 ≤ x ≤ 0.15 were prepared by solid state synthesis. Rietveld powder X-ray diffraction (XRD refinements combined with Electron Probe Micro Analyses (EPMA, WDS-Wavelength Dispersive Spectroscopy and Raman spectra of all samples confirmed the stannite structure (Cu2FeSnS4-type as the main phase. In addition to the main phase, small amounts of secondary phases like ZnSe, CuSe and SnSe were observed. Transport properties of all samples were measured as a function of temperature in the range from 300 K to 720 K. The electrical resistivity of all samples decreases with an increase in Cu content except for Cu2.1ZnSn0.9Se4, most likely due to a higher content of the ZnSe. All samples showed positive Seebeck coefficients indicating that holes are the majority charge carriers. The thermal conductivity of doped samples was high compared to Cu2ZnSnSe4 and this may be due to the larger electronic contribution and the presence of the ZnSe phase in the doped samples. The maximum zT = 0.3 at 720 K occurs for Cu2.05ZnSn0.95Se4 for which a high-pressure torsion treatment resulted in an enhancement of zT by 30% at 625 K.

Dependency in State Transitions of Wind Turbines

DEFF Research Database (Denmark)

Herp, Jürgen; Ramezani, Mohammad Hossein; S. Nadimi, Esmaeil

2017-01-01

© 2017 IEEE. Turbine states and predicting the transition into failure states ahead of time is important in operation and maintenance of wind turbines. This study presents a method to monitor state transitions of a wind turbine based on the online inference on residuals. In a Bayesian framework...... be abstracted from generated data. Two models are presented: 1) assuming independence and 2) assuming dependence between states. In order to select the right models, machine learning is utilized to update hyperparameters on the conditional probabilities. Comparing fixed to learned hyperparameters points out...... the impact machine learning concepts have on the predictive performance of the presented models. In conclusion, a study on model residuals is performed to highlight the contribution to wind turbine monitoring. The presented algorithm can consistently detect the state transition under various configurations...

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%.

Synthesis and electrochemical performance of Sn-doped Li3V2(PO4)3/C cathode material for lithium ion battery by microwave solid-state technique

International Nuclear Information System (INIS)

Liu, Haiping; Bi, Sifu; Wen, Guangwu; Teng, Xiangguo; Gao, Peng; Ni, Zujun; Zhu, Yongming; Zhang, Fang

2012-01-01

Highlights: ► Li 3 V 2−x Sn x (PO 4 ) 3 /C (0 ⩽ x ⩽ 0.10) cathode is first reported. ► Sn doping improves the initial discharge capacity and the cycle stability of Li 3 V 2 (PO 4 ) 3 /C. ► Sn doping improves the conductivity and reversibility of the Li 3 V 2 (PO 4 ) 3 /C. - Abstract: Li 3 V 2−x Sn x (PO 4 ) 3 /C cathode materials with uniform and fine particle sizes were successfully and fast synthesized by a microwave solid-state synthesis method. X-ray diffraction patterns demonstrated that the appropriate addition of Sn did not destroy the lattice structure of Li 3 V 2 (PO 4 ) 3 /C, but decreased the unit cell volume. X-ray photoelectron spectroscopy analysis demonstrated that the main chemical state of V in the Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C composite is +3 valence, while the chemical state of Sn in the Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C is +4 valence. Scanning electron microscope analysis illustrated that the addition of Sn slightly affected the morphology of samples. As the cathode materials for Li-ion batteries, Li 3 V 2−x Sn x (PO 4 ) 3 /C (x ⩽ 0.10) exhibited higher discharge capacity and better cycle stability than the pure one. At a discharge rate of 0.5 C in the potential range of 2.5–4.5 V at room temperature, the initial discharge capacity of Li 3 V 1.95 Sn 0.05 (PO 4 ) 3 /C was 136 mA h/g. The low charge-transfer resistances and large lithium ion diffusion coefficients confirmed that Sn-doped Li 3 V 2 (PO 4 ) 3 /C samples possessed better electronic conductivity and lithium ion mobility. These improved electrochemical performances can be attributed to the appropriate amount of Sn doping in Li 3 V 2 (PO 4 ) 3 /C system by enhancing structural stability and electrical conductivity. The present study also demonstrates that the microwave processing is a fast, simple and useful method for the fabrication of Li 3 V 2 (PO 4 ) 3 /C crystals.

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

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.

Spectroscopic ellipsometry study of Cu2ZnSnS4 bulk poly-crystals

Science.gov (United States)

Levcenko, S.; Hajdeu-Chicarosh, E.; Garcia-Llamas, E.; Caballero, R.; Serna, R.; Bodnar, I. V.; Victorov, I. A.; Guc, M.; Merino, J. M.; Pérez-Rodriguez, A.; Arushanov, E.; León, M.

2018-04-01

The linear optical properties of Cu2ZnSnS4 bulk poly-crystals have been investigated using spectroscopic ellipsometry in the range of 1.2-4.6 eV at room temperature. The characteristic features identified in the optical spectra are explained by using the Adachi analytical model for the interband transitions at the corresponding critical points in the Brillouin zone. The experimental data have been modeled over the entire spectral range taking into account the lowest E0 transition near the fundamental absorption edge and E1A and E1B higher energy interband transitions. In addition, the spectral dependences of the refractive index, extinction coefficient, absorption coefficient, and normal-incidence reflectivity values have been accurately determined and are provided since they are essential data for the design of Cu2ZnSnS4 based optoelectronic devices.

Spin dynamics of the Kondo insulator CeNiSn approaching the metallic phase

DEFF Research Database (Denmark)

Schröder, A.; Aeppli, G.; Mason, T.E.

1997-01-01

The spin dynamics of Kondo insulators has been studied by high-resolution magnetic neutron spectroscopy at a triple-axes spectrometer on CeNi1-xCuxSn single crystals using a vertical 9 T magnet. While upon doping (x = 0.13) the spin gap of the Kondo insulator CeNiSn collapses at the transition to...

Influence of Sn content on PtSn/C catalysts for electrooxidation of C{sub 1}-C{sub 3} alcohols: Synthesis, characterization, and electrocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Hong; Choi, Sung Mook; Nam, Sang Hoon; Seo, Min Ho; Kim, Won Bae [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea); Choi, Sun Hee [Pohang Accelerator Laboratory, San-31 Hyoja-dong, Pohang, Kyungbuk 790-984 (Korea)

2008-07-16

A series of carbon-supported bimetallic PtSn catalysts for the electrooxidation of C{sub 1}-C{sub 3} alcohols (i.e., methanol (C{sub 1}), ethanol (C{sub 2}), and 1-propanol (C{sub 3})) were prepared with different Pt:Sn atomic ratios using borohydride reduction method combined with freeze-drying procedure at room temperature. The catalysts were investigated by employing various physicochemical analyses: X-ray diffraction (XRD), transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) to investigate the structural modification, and X-ray photoelectron spectroscopy (XPS) and X-ray absorption-near-edge spectroscopy (XANES) to characterize the change in electronic features. The variation of Sn content by forming PtSn alloys causes significant structural and electronic modifications of Pt crystallites, resulting in increases of lattice parameter and decreases of the Pt 5d band vacancies with Sn content. Cyclic voltammetry (CV) measurements showed that the addition of Sn into the Pt catalyst promotes the electro-catalytic activities for the electrooxidations of C{sub 1}, C{sub 2}, and C{sub 3} alcohols, in which the maximum activities appeared at different Sn contents for the C{sub 1}-C{sub 3} alcohols. In particular, a shift in optimum Pt:Sn composition was observed in that the Sn content required to reach the maximum peak current density was increased with the increasing number of carbon atoms in the C{sub 1}-C{sub 3} alcohols. Both the geometric and electronic effects with variation of Sn content are in close relationship in the bimetallic PtSn catalysts, consequently affecting the electrocatalytic activities by showing volcano-type behaviors over the electrooxidation of the individual alcohol. (author)

Systematic and controllable negative, zero, and positive thermal expansion in cubic Zr(1-x)Sn(x)Mo2O8.

Science.gov (United States)

Tallentire, Sarah E; Child, Felicity; Fall, Ian; Vella-Zarb, Liana; Evans, Ivana Radosavljević; Tucker, Matthew G; Keen, David A; Wilson, Claire; Evans, John S O

2013-08-28

We describe the synthesis and characterization of a family of materials, Zr1-xSnxMo2O8 (0 thermal expansion coefficient can be systematically varied from negative to zero to positive values. These materials allow tunable expansion in a single phase as opposed to using a composite system. Linear thermal expansion coefficients, αl, ranging from -7.9(2) × 10(-6) to +5.9(2) × 10(-6) K(-1) (12-500 K) can be achieved across the series; contraction and expansion limits are of the same order of magnitude as the expansion of typical ceramics. We also report the various structures and thermal expansion of "cubic" SnMo2O8, and we use time- and temperature-dependent diffraction studies to describe a series of phase transitions between different ordered and disordered states of this material.

The cysteine rich necrotrophic effector SnTox1 produced by Stagonospora nodorum triggers susceptibility of wheat lines harboring Snn1.

Directory of Open Access Journals (Sweden)

Zhaohui Liu

2012-01-01

Full Text Available The wheat pathogen Stagonospora nodorum produces multiple necrotrophic effectors (also called host-selective toxins that promote disease by interacting with corresponding host sensitivity gene products. SnTox1 was the first necrotrophic effector identified in S. nodorum, and was shown to induce necrosis on wheat lines carrying Snn1. Here, we report the molecular cloning and validation of SnTox1 as well as the preliminary characterization of the mechanism underlying the SnTox1-Snn1 interaction which leads to susceptibility. SnTox1 was identified using bioinformatics tools and verified by heterologous expression in Pichia pastoris. SnTox1 encodes a 117 amino acid protein with the first 17 amino acids predicted as a signal peptide, and strikingly, the mature protein contains 16 cysteine residues, a common feature for some avirulence effectors. The transformation of SnTox1 into an avirulent S. nodorum isolate was sufficient to make the strain pathogenic. Additionally, the deletion of SnTox1 in virulent isolates rendered the SnTox1 mutated strains avirulent on the Snn1 differential wheat line. SnTox1 was present in 85% of a global collection of S. nodorum isolates. We identified a total of 11 protein isoforms and found evidence for strong diversifying selection operating on SnTox1. The SnTox1-Snn1 interaction results in an oxidative burst, DNA laddering, and pathogenesis related (PR gene expression, all hallmarks of a defense response. In the absence of light, the development of SnTox1-induced necrosis and disease symptoms were completely blocked. By comparing the infection processes of a GFP-tagged avirulent isolate and the same isolate transformed with SnTox1, we conclude that SnTox1 may play a critical role during fungal penetration. This research further demonstrates that necrotrophic fungal pathogens utilize small effector proteins to exploit plant resistance pathways for their colonization, which provides important insights into the molecular

NEMO-SN-1 the first 'real-time' seafloor observatory of ESONET

International Nuclear Information System (INIS)

Favali, Paolo; Beranzoli, Laura; D'Anna, Giuseppe; Gasparoni, Francesco; Gerber, Hans W.

2006-01-01

The fruitful collaboration between Italian Research Institutions, particularly Istituto Nazionale di Fisica Nucleare (INFN) and Istituto Nazionale di Geofisica e Vulcanologia (INGV) together with Marine Engineering Companies, led to the development of NEMO-SN-1, the first European cabled seafloor multiparameter observatory. This observatory, deployed at 2060 m w.d. about 12 miles off-shore the Eastern coasts of Sicily (Southern Italy), is in real-time acquisition since January 2005 and addressed to different set of measurements: geophysical and oceanographic. In particular the SN-1 seismological data are integrated in the INGV land-based national seismic network, and they arrive in real-time to the Operative Centre in Rome. In the European Commission (EC) European Seafloor Observatory NETwork (ESONET) project, in connection to the Global Monitoring for Environment and Security (GMES) action plan, the NEMO-SN-1 site has been proposed as an European key area, both for its intrinsic importance for geo-hazards and for the availability of infrastructure as a stepwise development in GMES program. Presently, NEMO-SN-1 is the only ESONET site operative. The paper gives a description of SN-1 observatory with examples of data

Moessbauer study of phase transitions under high hydrostatic pressures. 1

International Nuclear Information System (INIS)

Kapitanov, E.V.; Yakovlev, E.N.

1979-01-01

Experimental results of the hydrostatic pressure influence on Moessbauer spectrum parameters are obtained over the pressure range including the area of structural phase transition. A linear increase of the Moessbauer effect probability (recoilless fraction) is accompanied by a linear decrease of the electron density at tin nuclei within the pressure range foregoing the phase transition. The electric resistance and the recoilless fraction of the new phase of Mg 2 Sn are lower, but the electron density at tin nuclei is greater than the initial phase ones. Hydrostatic conditions allow to fix clearly the diphasic transition area and to determine the influence of the pressure on the Moessbauer line position and on the recoilless fraction of the high pressure phase. The phase transition heat Q = 415 cal mol -1 is calculated using recoilless fractions of the high and low pressure phases at 25 kbar. The present results are qualitatively and quantitatively different from the results, obtained at nonhydrostatic conditions. (author)

Solid-state diffusion-controlled growth of the phases in the Au-Sn system

Science.gov (United States)

Baheti, Varun A.; Kashyap, Sanjay; Kumar, Praveen; Chattopadhyay, Kamanio; Paul, Aloke

2018-01-01

The solid state diffusion-controlled growth of the phases is studied for the Au-Sn system in the range of room temperature to 200 °C using bulk and electroplated diffusion couples. The number of product phases in the interdiffusion zone decreases with the decrease in annealing temperature. These phases grow with significantly high rates even at the room temperature. The growth rate of the AuSn4 phase is observed to be higher in the case of electroplated diffusion couple because of the relatively small grains and hence high contribution of the grain boundary diffusion when compared to the bulk diffusion couple. The diffraction pattern analysis indicates the same equilibrium crystal structure of the phases in these two types of diffusion couples. The analysis in the AuSn4 phase relating the estimated tracer diffusion coefficients with grain size, crystal structure, the homologous temperature of experiments and the concept of the sublattice diffusion mechanism in the intermetallic compounds indicate that Au diffuses mainly via the grain boundaries, whereas Sn diffuses via both the grain boundaries and the lattice.

Spectroscopy of particle-phonon coupled states in $^{133}$Sb by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li

CERN Multimedia

We propose to investigate, with MINIBALL coupled to T-REX, the one-valence-proton $^{133}$Sb nucleus by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li. The excited $^{133}$Sb will be populated by transfer of a triton into $^{132}$Sn, followed by the emission of an $\\alpha$-particle (detected in T-REX) and 2 neutrons. The aim of the experiment is to locate states arising from the coupling of the valence proton of $^{133}$Sb to the collective low-lying phonon excitations of $^{132}$Sn (in particular the 3$^−$). According to calculations in the weak-coupling approach, these states lie in the 4$\\, - \\,$5 MeV excitation energy region and in the spin interval 1/2$\\, - \\,$ 19/2, i.e., in the region populated by the cluster transfer reaction. The results will be used to perform advanced tests of different types of nuclear interactions, usually employed in the description of particle-phonon coupled excitations. States arising from couplings of the proton with simpler core excitations, involving few nucleons...

Preparation and near-infrared absorption of nano-SnO{sub 2}/SiO{sub 2} assemblies with doping and without doping

Energy Technology Data Exchange (ETDEWEB)

Hai Shujie [Faculty of Material Science and Chemical Engineering, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China); Yan Chunjie, E-mail: chjyan2005@126.co [Engineering Research Center of Nano-Geomaterials, Ministry of Education, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China); Yu Hongjie; Xiao Guoqi; Wang Duo [Faculty of Material Science and Chemical Engineering, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China)

2009-11-20

The assemblies of nano-SnO{sub 2}/SiO{sub 2} and Sb- or Pd-doped nano-SnO{sub 2}/SiO{sub 2}, in which the nano-SnO{sub 2} particles are located in the pores of mesoporous SiO{sub 2} dry gels, were synthesized. Only for the Sb-doped nano-SnO{sub 2}/SiO{sub 2} assemblies, a broad near-infrared absorption step occurs in the optical absorption spectrum of the wavelength range from 300 to 1500 nm. The near-infrared absorption phenomenon is attributed to electronic transitions from the ground states to the excitation states of the impurity energy levels, which are formed by Sb doping in SnO{sub 2}. With increasing the weight ratio of SnO{sub 2}:SiO{sub 2} or the annealing temperature, the near-infrared absorption step slope side exhibits 'red shift', which is caused by the quantum confinement effect weakening due to the increased SnO{sub 2} crystalline diameter.

A hyperactive transcriptional state marks genome reactivation at the mitosis–G1 transition

Science.gov (United States)

Hsiung, Chris C.-S.; Bartman, Caroline R.; Huang, Peng; Ginart, Paul; Stonestrom, Aaron J.; Keller, Cheryl A.; Face, Carolyne; Jahn, Kristen S.; Evans, Perry; Sankaranarayanan, Laavanya; Giardine, Belinda; Hardison, Ross C.; Raj, Arjun; Blobel, Gerd A.

2016-01-01

During mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis–G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis–G1 transition, ∼50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer–promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry but do not spike. Of the chromatin-associated features examined, histone H3 Lys27 acetylation levels at individual loci in mitosis best predict the mitosis–G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis–G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis–G1 transition might predispose cells to diverge in gene expression states. PMID:27340175

Study of 16KhSN high strength steel in different structural states and under working conditions

International Nuclear Information System (INIS)

Skudnov, V.A.; Vorob'ev, I.A.; Kutyajkin, V.G.; Bugrov, Yu.V.

1985-01-01

A study was made on the effect of deformation degree (up to 60%) during reducing, drawing and heat treatment (annealing at 750 deg C), quenching from 930 deg C and tempering at 350 deg C) on strength, plasticity, hardening degree, notch sensitivity, density and elasticity characteristics of the steel. The effect of test temperature (from-196 up to 1000 deg C) on tensile strength and plasticity was studied as well. It was established that drawing and reducing of 16KhSN steel in annealed state with strain degrees of up to 60% results to increase of strength characteristics 1.7...2.3 times and decrease of plasticity characteristics by 15...23%, strain hardening coefficient - 2.2 times and the maximum strain energy - by 80 MJ/m 3 . Hardening heat treatment (quenching from 930 deg C+temperating at 350 deg C) affects on mechanical properties of 16KhSN steel in much the same way as cold working, but strength characteristics of heat-treated steel increase 2.6...3.6 times and the maximum strain energy grows by 640 MJ/m 3 . Systematic data on the effect of temperature (-196...1000 deg C) and tensile rate (4 mm/min...5m/s) on strength and plasticity of 16KhSN steel in annealed state were obtained

State diagrams of tokamaks and state transitions

International Nuclear Information System (INIS)

Minardi, E.

1992-01-01

In a simple one-fluid cylindrical model of transport and of dissipative effects, the family of the magnetic states of the Tokamak which correspond to a vanishing entropy production in the confinement region is characterized by a define relation or ''state equation'' involving the relevant parameters of the discharge. An investigation is made as to how the entropy production changes when the current density profile is rearranged by a perturbation which conserves the poloidal magnetic flux. It is shown that for a sufficiently short time interval, that is to say t 2 E τ s where τ E is the energy confinement time and τ s is the resistive time, neighbouring bifurcating equilibria exist which can be reached with a flux-conserving transition and with increase of the magnetic entropy. The family of these new states can also be characterized by a state equation involving the relevant discharge parameters. When the state equations of the two families are simultaneously satisfied by the same set of parameter values, a flux-conserving, entropy-increasing transition may take place between states of the two families. The modifications of the current density and of the temperature profiles involved in the transition and the conditions that the discharge parameters should satisfy in order that the transition could occur are investigated. (author)

A comparative study of the magnetization in transition metal ion doped CeO2, TiO2 and SnO2 nanoparticles

Science.gov (United States)

Apostolov, A. T.; Apostolova, I. N.; Wesselinowa, J. M.

2018-05-01

Using the microscopic s-d model taking into account anharmonic spin-phonon interactions we have studied the magnetic properties of Co and Cu ion doped CeO2 and TiO2 nanoparticles and compared them with those of SnO2. By Co-doping there is a maximum in the magnetization M(x) curve for all nanoparticles observed in the most transition metal doped ones. The s-d interaction plays an important role by the decrease of M at higher dopant concentration. We have discussed the magnetization in dependence of different model parameters. By small Cu-ion doping there are some differences. In CeO2M decreases with the Cu-concentration, whereas in TiO2 and SnO2M increases. For higher Cu dopant concentrations M(X) decreases in TiO2 nanoparticles. We obtain room temperature ferromagnetism also in Zn doped CeO2, TiO2 and SnO2 nanoparticles, i.e. in non-transition metal ion doped ones. The different behavior of M in Co and Cu doped nanoparticles is due to a combination effect of multivalent metal ions, oxygen vacancies, different radius of cation dopants, connection between lattice and magnetism, as well as competition between the s-d and d-d ferromagnetic or antiferromagnetic interactions.

The pure rotational spectra of the open-shell diatomic molecules PbI and SnI.

Science.gov (United States)

Evans, Corey J; Needham, Lisa-Maria E; Walker, Nicholas R; Köckert, Hansjochen; Zaleski, Daniel P; Stephens, Susanna L

2015-12-28

Pure rotational spectra of the ground electronic states of lead monoiodide and tin monoiodide have been measured using a chirped pulsed Fourier transform microwave spectrometer over the 7-18.5 GHz region for the first time. Each of PbI and SnI has a X (2)Π1/2 ground electronic state and may have a hyperfine structure that aids the determination of the electron electric dipole moment. For each species, pure rotational transitions of a number of different isotopologues and their excited vibrational states have been assigned and fitted. A multi-isotopologue Dunham-type analysis was carried out on both species producing values for Y01, Y02, Y11, and Y21, along with Λ-doubling constants, magnetic hyperfine constants and nuclear quadrupole coupling constants. The Born-Oppenheimer breakdown parameters for Pb have been evaluated and the parameter rationalized in terms of finite nuclear field effects. Analysis of the bond lengths and hyperfine interaction indicates that the bonding in both PbI and SnI is ionic in nature. Equilibrium bond lengths have been evaluated for both species.

Effect of point defects on the electronic density states of SnC nanosheets: First-principles calculations

Directory of Open Access Journals (Sweden)

Soleyman Majidi

Full Text Available In this work, we investigated the electronic and structural properties of various defects including single Sn and C vacancies, double vacancy of the Sn and C atoms, anti-sites, position exchange and the Stone–Wales (SW defects in SnC nanosheets by using density-functional theory (DFT. We found that various vacancy defects in the SnC monolayer can change the electronic and structural properties. Our results show that the SnC is an indirect band gap compound, with the band gap of 2.10 eV. The system turns into metal for both structure of the single Sn and C vacancies. However, for the double vacancy contained Sn and C atoms, the structure remains semiconductor with the direct band gap of 0.37 eV at the G point. We also found that for anti-site defects, the structure remains semiconductor and for the exchange defect, the structure becomes indirect semiconductor with the K-G point and the band gap of 0.74 eV. Finally, the structure of SW defect remains semiconductor with the direct band gap at K point with band gap of 0.54 eV. Keywords: SnC nanosheets, Density-functional theory, First-principles calculations, Electronic density of states, Band gap

Energies, wavelengths, and transition probabilities for Ge-like Kr, Mo, Sn, and Xe ions

International Nuclear Information System (INIS)

Nagy, O.; El Sayed, Fatma

2012-01-01

Energy levels, wavelengths, transition probabilities, and oscillator strengths have been calculated for Ge-like Kr, Mo, Sn, and Xe ions among the fine-structure levels of terms belonging to the ([Ar] 3d 10 )4s 2 4p 2 , ([Ar] 3d 10 )4s 4p 3 , ([Ar] 3d 10 )4s 2 4p 4d, and ([Ar] 3d 10 )4p 4 configurations. The fully relativistic multiconfiguration Dirac–Fock method, taking both correlations within the n=4 complex and the quantum electrodynamic effects into account, have been used in the calculations. The results are compared with the available experimental and other theoretical results.

Evidence of parity violation in 118Sn and 36Cl

International Nuclear Information System (INIS)

Benkoula, H.

1978-01-01

Parity violation in nuclear systems was studied by forward-backward asymmetry measurement methods in radiative capture of polarized neutrons in the reactions 117 Sn(n,γ) 118 Sn and 35 Cl(n,γ) 36 Cl. The experimental set ups used two INa detectors situated at left and right sides of the beam and parallel to polarisation direction, and an electronic system adapted to high-counting rate. The asymmetry measurement, A=(4.56+-0.6)x10 -4 in the 9.328 MeV Ml transition demonstrates the existence of parity violation effects. The 8.58 MeV (M1+E2) transition in 36 Cl was also studied and the asymmetry value is A=(1.11+-0.35)x10 -4 . Several beam and electronic tests have shown that there was no spurious asymmetry in the measurement due to the equipment [fr

Structural complexity and thermoelectric properties of quaternary and quinary tellurides (Ge{sub x}Sn{sub 1-x}){sub 0.8}(In{sub y}Sb{sub 1-y}){sub 0.13}Te with 0 ≤ x,y ≤ 1

Energy Technology Data Exchange (ETDEWEB)

Neudert, Lukas; Scheel, Manuel [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen (Germany); Schwarzmueller, Stefan; Welzmiller, Simon; Oeckler, Oliver [Institut fuer Mineralogie, Kristallographie und Materialwissenschaft, Fakultaet fuer Chemie und Mineralogie, Universitaet Leipzig (Germany)

2017-12-13

Starting from stoichiometric mixtures of the elements, quaternary and quinary solid solutions (Ge{sub x}Sn{sub 1-x}){sub 0.8}(In{sub y}Sb{sub 1-y}){sub 0.13}Te were obtained. Concerning the ratio Ge/Sn and Sb/In, respectively, lattice parameters of the metastable phases with rocksalt-type average structures approximately obey Vegard's law. Stable phases correspond to a disordered rocksalt type at high temperature and to trigonal layered structures with van der Waal gaps at lower temperature as shown by temperature-dependent powder X-ray diffraction combined with TEM, which reveals layer-like vacancy ordering, whose extent depends on composition and thermal treatment. In the long-periodically ordered model compounds 21R-Ge{sub 0.5}Sn{sub 0.5}InSbTe{sub 4} and 9P-GeSnInSbTe{sub 5} studied by resonant scattering data at K-absorption edges, Sb and Sn concentrate near the van der Waals gaps. Compared to Ge{sub 0.8}Sb{sub 0.13}Te and Sn{sub 0.8}Sb{sub 0.13}Te, the simultaneous presence of In and Sn combines increased electrical conductivity with low thermal conductivity and enhanced thermoelectric properties in certain temperature ranges. Phase transitions correlate with changes of the thermoelectric properties. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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)

Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds

Science.gov (United States)

Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

2018-02-01

The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.

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

Study of Bi-2212 phase doped Sn(Pb) by means of pat

International Nuclear Information System (INIS)

Ma Qingzhu; Huang Xiaoqian; Xiong Xiaotao

1997-01-01

Investigation on the effect of Sn/Pb-doped Bi-2212 superconductors has been carried out by the simultaneous measurements of the spectra of positron annihilation lifetime and positron Doppler broadening, together with X-ray diffraction. The results of samples with different doping level show the occupation of Sn atoms on Bi sites. At weak doping level, Sn doping results in a enhancement of cooperation between layers and increment of superconducting transition temperature. At the strong doping level, Sn atoms occupy the sites of Cu-O layers, and at the same time, the other nonsuperconducting phases appear, which results in a decline of the superconducting transition temperature

Structural stability of ternary C22–Zr{sub 6}X{sub 2}Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and C22–Zr{sub 6}Sn{sub 2}T′ (T′=Fe, Co, Ni, Cu) compounds

Energy Technology Data Exchange (ETDEWEB)

Colinet, Catherine, E-mail: ccolinet@simap.grenoble-inp.fr [Science et Ingénierie des Matériaux et Procédés, Grenoble INP, UJF, CNRS, 38402 Saint Martin d’Hères, Cedex (France); Crivello, Jean-Claude [ICMPE-CMTR, CNRS UMR-7182, 2-8 rue Henri Dunant, 94320 Thiais (France); Tedenac, Jean-Claude [Institut de Chimie Moléculaire et des Matériaux I.C.G., UMR-CNRS 5253, Université Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5 (France)

2013-09-15

The crystal and electronic structures, and the thermodynamic properties of Zr{sub 6}X{sub 2}Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and Zr{sub 6}Sn{sub 2}T′ (T′=Fe, Co, Ni, Cu) ternary compounds in the Fe{sub 2}P-type structure have been investigated by means of first principle calculations. The calculated structural parameters are in good agreement with the experimental data. The total electronic densities of states as well as the Bader charges of the atoms have been computed. Both electronic and size effects allow to explain the stability of the ternary Zr{sub 6}X{sub 2}Co (X=Al, Ga, Sn, As, Sb, Bi, Te) and Zr{sub 6}Sn{sub 2}T′ (T′=Fe, Co, Ni, Cu) compounds. - Graphical abstract: Valence charge electronic localization function (ELF) calculated for Zr{sub 6}Sb{sub 2}Co compound. Display Omitted - Highlights: • Structural stability of Zr{sub 6}X{sub 2}T′ compounds (X: p element, T′: late transition metal) in the Fe{sub 2}P-type structure. • First principles calculation of lattice parameters and enthalpies of formation. • Electronic densities of state in the series Zr{sub 6}Sn{sub 2}T′ (T′=Fe, Co, Ni, Cu). • Electronic densities of state in the series Zr{sub 6}X{sub 2}Co (X=Al, Ga, Sn, As, Sb, Bi, Te)

On the thermopower and thermomagnetic properties of Er{sub x}Sn{sub 1–x}Se solid solutions

Energy Technology Data Exchange (ETDEWEB)

Huseynov, J. I., E-mail: cih-58@mail.ru; Murguzov, M. I.; Ismayilov, Sh. S.; Mamedova, R. F. [Azerbaijan State Pedagogical University (Azerbaijan); Gojayev, E. M. [Azerbaijan Technical University (Azerbaijan)

2017-02-15

The Er{sub x}Sn{sub 1–x}Se system is characterized by a significant deviation of the temperature dependence of the differential thermopower from linearity at temperatures below room temperature and a change in the sign of the thermomagnetic coefficient. The deviation of the thermopower of Er{sub x}Sn{sub 1–x}Se samples in the nonequilibrium state from linearity is found to be caused mainly by the entrainment of charge carriers by phonons α{sub ph}. The statistical forces of electronic entrainment, A{sub ph}(ε), are estimated.

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.

Effect of Sn additive on the structure and crystallization kinetics in Ge–Se alloy

Energy Technology Data Exchange (ETDEWEB)

Abd-Elrahman, M.I., E-mail: mostafaia11@yahoo.com; Hafiz, M.M.; Abdelraheem, A.M.; Abu-Sehly, A.A.

2016-08-05

The structure of Ge{sub 20}Se{sub 80−x}Snx glassy alloys and crystallization phases are identified using the X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). The glass transition kinetics and the crystallization mechanism of the system are studied using Differential Scanning Calorimeter (DSC) under non-isothermal condition. The results reveal that glass transition temperature (Tg) increases with increasing Sn content which is attributed to the increase in the coordination number. The increase of the glass transition activation energy (Eg) with increasing Sn content is attributed to the decrease in the internal energy of the system as Sn increases. The compositional dependence of both glass forming ability and thermal stability are studied. From the experimental data, the thermal stability parameter (S) is found to be maximum for Ge{sub 20}Se{sub 78}Sn{sub 2} alloy, which indicates that this alloy is thermally more stable in the composition range under investigation. The effect of composition on the crystallization mechanism is discussed using different kinetic models. The crystallization activation energy (Ec) decreases with increasing Sn. This is attributed to the addition of Sn increases the tendency of crystallization. The calculated values of Avrami exponent (n) indicates the crystallization process occurs in one-and two dimensions for Sn is less than or equals 12 at%, respectively. - Highlights: • Glass and crystallization transitions in Ge{sub 20}Se{sub 80−x}Sn{sub x} candidate for devices. • The addition of Sn increases the tendency of Ge-Se alloy to crystallization. • The glass forming ability and thermal stability increase as Sn decreases. • The dimension of the crystals growth is one or two depending on the Sn content.

Investigation of the (p,p'), (p,d) and (p,t) reactions on some light Sn isotopes

International Nuclear Information System (INIS)

Blankert, P.J.

1979-01-01

The results are presented of the 112 Sn(p,p') 112 Sn reaction. Apart from the usual distorted-wave analysis the excitation of some states is described in the coupled-channels formalism. The results of the 112 Sn(p,d) 111 Sn and the 112 Sn(p,t) 110 Sn reactions are also reported. From the (p,d) reaction quasi-particle energies and occupation numbers are determined. Two-step DWBA calculations are performed for some states that are assumed to result from the coupling of a quasiparticle to the 2 + 1 or 3 - 1 state of the even core. In the gross structure above 3 MeV of excitation, pickup strength from deeply-bound hole states is observed. The (p,t) reaction provided spin and parity of a number of levels in 110 Sn. A two-step DWBA analysis of the excitation of the ground state and first excited 2 + state shows the importance of second-order processes. The combined results of the (p,t) reactions on 112 Sn, 114 Sn and 116 Sn are given with some emphasis on the systematic features. The derivation is given of some expressions for spectroscopic amplitudes necessary in the two-step DWBA calculations for the (p,t) reactions. For all reactions a comparison is made with other existing data and with the results of model calculations. (Auth.)

Trehalose-6-phosphate and SnRK1 kinases in plant development and signaling: the emerging picture

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Sonia eGazzarrini

2014-04-01

Full Text Available Carbohydrates, or sugars, regulate various aspects of plant growth through modulation of cell division and expansion. Besides playing essential roles as sources of energy for growth and as structural components of cells, carbohydrates also regulate the timing of expression of developmental programs. The disaccharide trehalose is used as an energy source, as a storage and transport molecule for glucose, and as a stress-responsive compound important for cellular protection during stress in all kingdoms. Trehalose, however, is found in very low amounts in most plants, pointing to a signaling over metabolic role for this non-reducing disaccharide. In the last decade, trehalose-6-phosphate (T6P, an intermediate in trehalose metabolism, has been shown to regulate embryonic and vegetative development, flowering time, meristem determinacy and cell fate specification in plants. T6P acts as a global regulator of metabolism and transcription promoting plant growth and triggering developmental phase transitions in response to sugar availability. Among the T6P targets are members of the Sucrose-non-fermenting1-Related Kinase1 (SnRK1 family, which are sensors of energy availability and inhibit plant growth and development during metabolic stress to maintain energy homeostasis. In this review, we will discuss the opposite roles of the sugar metabolite T6P and the SnRK1 kinases in the regulation of developmental phase transitions in response to carbohydrate levels. We will focus on how these two global regulators of metabolic processes integrate environmental cues and interact with hormonal signaling pathways to modulate plant development.

Martensitic transformation and magnetic properties of manganese-rich Ni-Mn-In and Ni-Mn-Sn Heusler alloys; Untersuchung der martensitischen Umwandlung und der magnetischen Eigenschaften Mangan-reicher Ni-Mn-In- und Ni-Mn-Sn-Heusler-Legierungen

Energy Technology Data Exchange (ETDEWEB)

Krenke, T.

2007-06-29

In the present work, the martensitic transition and the magnetic properties of Manganese rich Ni{sub 50}Mn{sub 50-x}Sn{sub x} and Ni{sub 50}Mn{sub 50-y}In{sub y} alloys with 5 at%{<=}x(y){<=}25 at% were investigated. Calorimetry, X-ray and neutron diffraction, magnetization, and strain measurements were performed on polycrystalline samples. It was shown that alloys close to the stoichiometric composition Ni{sub 50}Mn{sub 25}Sn{sub 25} and Ni{sub 50}Mn{sub 25}Sn{sub 25} do not exhibit a structural transition on lowering of the temperature, whereas alloys with x{<=}15 at% Tin and y{<=}16 at% Indium transform martensitically. The structural transition temperatures increase linearly with decreasing Tin or Indium content. The crystal structures of the low temperature martensite are modulated as well as unmodulated. Alloys with compositions close to stoichiometry are dominated by ferromagnetic interactions, whereas those close to the binary composition Ni{sub 50}Mn{sub 50} order antiferromagnetically. Ferromagnetic order and structural instability coexist in a narrow composition range between 13 at%{<=}x{<=}15 at% and 15 at%{<=}x{<=}16 at% for Ni{sub 50}Mn{sub 50-x}Sn{sub x} and Ni{sub 50}Mn{sub 50-y}In{sub y} respectively. As a consequence, interesting magnetoelastic effects are observed. The Ni{sub 50}Mn{sub 34}In{sub 16} alloy shows a magnetic field-induced structural transition, whereby application of an external magnetic field in the martensitic state stabilizes the high temperature L2{sub 1} structure. Evidence for this was given by neutron diffraction experiments in external magnetic fields. Moreover, the structural transition temperatures of this alloy show large magnetic field dependencies. By use of calorimetry, M(T), and strain measurements, changes in M{sub s} up to -11 K/Tesla are observed. Such large values have, until now, not been observed in Heusler alloys. Since during transformation the volume changes reversibly, magnetic field-induced strains of about

Preparation of highly dispersed Ru-Sn bimetallic supported catalysts from the single source precursors Cp(PPh32Ru-SnX3 (X = Cl or Br

Directory of Open Access Journals (Sweden)

Ana Cláudia Bernardes Silva

2003-06-01

Full Text Available In this work highly dispersed Ru-Sn bimetallic catalysts have been prepared from organobimetallic Cp(PPh32Ru-SnX3 (X = Cl or Br complexes. These single source precursors can be easily impregnated in high surface area supports, such as activated carbon and sol-gel SiO2, and upon controlled thermal treatment the ligands are released as volatile products resulting in the formation of the bimetallic system Ru-Sn. Catalytic reactions, such as hydrodechlorination of CCl4 and chlorobenzene and TPR (Temperature Programmed Reduction experiments carried out with these RuSn catalysts suggested a strong interaction between Ruthenium and Tin. Mössbauer measurements showed that these materials when exposed to air are immediately oxidized to form Sn (IV. It was shown that upon controlled reduction conditions with H2 it is possible to reduce selectively Sn to different oxidation states and different phases. The Sn oxidation state showed significant effect on the catalytic hydrogenation of 1,5-cyclooctadiene. The use of these single source precursors with a controlled decomposition/reduction procedure allows the preparation of unique catalysts with an intimate interaction between the components ruthenium and tin and the possibility of varying the Sn oxidation state around the Ru metal.

The complex becomes more complex: protein-protein interactions of SnRK1 with DUF581 family proteins provide a framework for cell- and stimulus type-specific SnRK1 signaling in plants

Directory of Open Access Journals (Sweden)

Madlen eNietzsche

2014-02-01

Full Text Available In plants, SNF1-related kinase (SnRK1 responds to the availability of carbohydrates as well as to environmental stresses by down-regulating ATP consuming biosynthetic processes, while stimulating energy-generating catabolic reactions through gene expression and post-transcriptional regulation. The functional SnRK1 complex is a heterotrimer where the catalytic alpha subunit associates with a regulatory beta subunit and an activating gamma subunit. Several different metabolites as well as the hormone abscisic acid (ABA have been shown to modulate SnRK1 activity in a cell- and stimulus-type specific manner. It has been proposed that tissue- or stimulus-specific expression of adapter proteins mediating SnRK1 regulation can at least partly explain the differences observed in SnRK1 signaling. By using yeast two-hybrid and in planta bi-molecular fluorescence complementation assays we were able to demonstrate that proteins containing the domain of unknown function (DUF 581 could interact with both isoforms of the SnRK1 alpha subunit (AKIN10/11 of Arabidopsis. A structure/function analysis suggests that the DUF581 is a generic SnRK1 interaction module and co-expression with DUF581 proteins in plant cells leads to reallocation of the kinase to specific regions within the nucleus. Yeast two-hybrid analyses suggest that SnRK1 and DUF581 proteins can share common interaction partners inside the nucleus. The analysis of available microarray data implies that expression of the 19 members of the DUF581 encoding gene family in Arabidopsis is differentially regulated by hormones and environmental cues, indicating specialized functions of individual family members. We hypothesize that DUF581 proteins could act as mediators conferring tissue- and stimulus-type specific differences in SnRK1 regulation.

A hyperactive transcriptional state marks genome reactivation at the mitosis-G1 transition.

Science.gov (United States)

Hsiung, Chris C-S; Bartman, Caroline R; Huang, Peng; Ginart, Paul; Stonestrom, Aaron J; Keller, Cheryl A; Face, Carolyne; Jahn, Kristen S; Evans, Perry; Sankaranarayanan, Laavanya; Giardine, Belinda; Hardison, Ross C; Raj, Arjun; Blobel, Gerd A

2016-06-15

During mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis-G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis-G1 transition, ∼50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer-promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry but do not spike. Of the chromatin-associated features examined, histone H3 Lys27 acetylation levels at individual loci in mitosis best predict the mitosis-G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis-G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis-G1 transition might predispose cells to diverge in gene expression states. © 2016 Hsiung et al.; Published by Cold Spring Harbor Laboratory Press.

Role of quasiparticle x phonon components in gamma-decay of hogh-lying states

International Nuclear Information System (INIS)

Ponomarev, V.Yu.; Solov'ev, V.G.; Vdovin, A.I.; Stoyanov, Ch.

1986-01-01

In the framework of quasiparticle-phonon model of a nucleus the probabilities of gamma-transitions (E1, M1, E2) from a high-lying resonance-similar structure to the excitation of neutron hole state (lg 9/2 ) -1 of 111 Sn nucleus to the main and low-excited one-quasiparticle states have been calculated. Wave function of a highly excited state comprised the components ''quasiparticle x phonon'' and ''quasiparticle x two phonons''. For E1-transitions 9/2 + → 11/2 1 - the main contribution to the transition is made by one-quasiparticle components of wave functions of the initial and final states. E2-transition 9/2 + → 7/2 g,s + takes place at the expense of impurities in ''quasiparticle x phonon'' states. For M1-transition from the states 9/2 + to the main one a strong destructive interference of contributions of one-quasiparticle and ''quasiparticle x phonon'' components is observed. Thus it is shown that components ''quasiparticle x phonon'' may play the major role in correct description of gamma-transitions from high-lying one-particle or low-lying hole states

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.

Ionic fragmentation following core-level photoionization of Sn(CH3)4 by soft X-rays

International Nuclear Information System (INIS)

Ueda, Kiyoshi; Shigemasa, Eiji; Sato, Yukinori; Yagishita, Akira; Hayaishi, Tatsuji

1990-01-01

Ionic fragmentation following the photoionization of Sn(CH 3 ) 4 (TMT) has been studied in the photon energy range of 60-600 eV using synchrotron radiation and time-of-flight mass spectrometry. Each of the Sn:4d, 4p, 3d and C:1s photoionization leads to a type of ionic fragmentation that is characteristic of each ionized core. The Sn:4d photoionization above 60 eV predominantly produces the doubly-charged TMT which dissociates into two singly-charged ions and some neutral fragments. The ions produced in this pathway are CH 3 + , C 2 H 3 + , C 2 H 5 + , SnCH m + and/or Sn + . The Sn:4p photoionization produces the triply-charged TMT and enhances the production of H + , CHsub(m' + ) (m' = 0-3) and Sn + significantly. The Sn:3d photoionization produces multiply-charged TMT whose charges are 3-5 and enhances the production of H + , CHsub(m' + ) (m' = 0-2) and Sn + significantly. The C:1s photoionization produces doubly-charged TMT via the KVV Auger transition and enhances the production of CH 3 + , C 2 H 3 + , SnCH m + and/or Sn + . (orig.)

Ultra Fast Timing Measurements at $^{78}$Ni and $^{132}$Sn

CERN Multimedia

2002-01-01

We propose to measure level lifetimes in the exotic nuclei of $^{81}$Ga and $^{80}$Ga in the vicinity of $^{78}$Ni and of $^{135}$Sb and $^{134}$Sb above $^{132}$Sn by the time-delayed technique. These are relatively simple nuclear systems with a few particles and/or holes outside of the doubly-magic core thus can be treated rather precisely within the shell model. The anticipated new structure information on these nuclei, and in particular the lifetime results will put constraints on the model parameters and will serve to verify their predictions. The selected nuclei are some of the most exotic ones just above $^{78}$Ni or $^{132}$Sn, where the transition rates can be studied at present. Of the strongest interest is the nucleus of $^{81}$Ga, which has only 3 valence protons outside of $^{78}$Ni with the lowest proton orbits being $p_{3/2}$ and $f_{5/2}$. The Ml transition between these states, although allowed by the selection rules, should be $\\textit{l}$-forbidden thus very slow. This should give rise to a...

Deep-hole and high-lying particle states in heavy nuclei

International Nuclear Information System (INIS)

Gales, S.

1985-01-01

Our present knowledge on single-particle strength functions from one nucleon transfer reactions is reviewed. Results on deeply-bound neutron hole states in the Sn and Pb region are discussed with emphasis on the investigation of a very large excitation energy range. The first measurements on the γ-decay of deeply-bound hole states in the Sn isotopes are reported. High energy neutron and proton stripping reactions are used to study the particle response function. These reactions are particularly well suited to the study of high-spin outer subshells. For the proton states, the behaviour of the 1h 11/2 and 1i 13/2 strength distributions, as a function of deformation in the Sm region, is discussed. Strong transitions to high-lying neutron states are observed in the 112, 116, 118, 120, 122, 124 Sn and 208 Pb nuclei. The empirical systematics for both proton and neutron particle strength distributions are compared to the predictions from the quasi particle-phonon and the single-particle vibration coupling nuclear models. (orig.)

SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana.

Science.gov (United States)

Soto-Burgos, Junmarie; Bassham, Diane C

2017-01-01

Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1 catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. These results demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis.

Study of intruder band in {sup 112}Sn

Energy Technology Data Exchange (ETDEWEB)

Ganguly, S. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Banerjee, P. [Saha Institute of Nuclear Physics, Kolkata 700064 (India)]. E-mail: polash.banerjee@saha.ac.in; Ray, I. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Kshetri, R. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Raut, R. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Bhattacharya, S. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Saha-Sarkar, M. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Goswami, A. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Mukhopadhyay, S. [UGC-DAE-CSR, Kolkata 700098 (India); Mukherjee, A. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Mukherjee, G. [Variable Energy Cyclotron Centre, Kolkata 700064 (India); Basu, S.K. [Variable Energy Cyclotron Centre, Kolkata 700064 (India)

2007-06-01

Excited states of the positive-parity intruder band in {sup 112}Sn, populated in the {sup 100}Mo({sup 20}Ne,{alpha}4n) reaction at a beam energy of 136 MeV, have been studied. The band has been observed up to 11570.0 keV with spin (24{sup +}). Mean lifetimes have been measured for six states up to the 22{sup +}, 10335.1 keV level and an upper limit of the lifetime has been estimated for the 11570.0 keV (24{sup +}) state. The B(E2) values, derived from the present lifetime results, correspond to a moderate quadrupole deformation of {beta}{sub 2}{approx}0.18 for states with spin J{sup {pi}}>=12{sup +}, and the decrease in B(E2) for the 14{sup +}->12{sup +} transition is consistent with a {nu}(h{sub 11/2}){sup 2} alignment at {omega}{approx}0.35 MeV, predicted by a cranked shell-model calculation. Total Routhian surface calculations predict a triaxial shape following the alignment.

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.

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

Effective charges in nuclei in the vicinity of $^{100}SN$

CERN Document Server

Ekström, Andreas

The shell structure of atomic nuclei far from the line of beta-stability and the properties of the nucleon-nucleon interaction in exotic isotopes are not well known. The development of radioactive ion beams (RIBs) puts certain unexplored regions of the nuclear chart within reach of detailed experimental investigations. The low-energy nuclear structure of the unstable isotopes 106,108,110Sn, 100,102,104Cd, and 106,108In have been studied using sub-barrier Coulomb excitation of postaccelerated RIBs. The experiments were carried out at the REX-ISOLDE facility at CERN. The deduced transition probabilities - B(E2) values - provide a detailed benchmark of modern models of the nucleon-nucleon interaction. The B(E2) values between the 0+ ground states and the first excited 2+ states in the Sn and Cd isotopes were compared with shell-model calculations. These are based on effective interactions derived from renormalized multi-meson and QCD-based nucleon-nucleon potentials. In order to reproduce the experimental result...

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.

Dopant spin states and magnetism of Sn{sub 1−x}Fe{sub x}O{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Punnoose, A., E-mail: apunnoos@boisestate.edu; Dodge, Kelsey; Reddy, K. M.; Franco, Nevil; Chess, Jordan; Eixenberger, Josh [Department of Physics, Boise State University, Boise, Idaho 83725-1570 (United States); Beltrán, J. J. [Department of Physics, Boise State University, Boise, Idaho 83725-1570 (United States); Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No 52-21, Medellín (Colombia); Barrero, C. A. [Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No 52-21, Medellín (Colombia)

2014-05-07

This work reports detailed investigations of a series of ∼2.6 nm sized, Sn{sub 1−x}Fe{sub x}O{sub 2} crystallites with x = 0–0.10 using Mossbauer spectroscopy, x-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR), and magnetometry to determine the oxidation state of Fe dopants and their role in the observed magnetic properties. The magnetic moment per Fe ion μ was the largest ∼6.48 × 10{sup −3} μ{sub B} for the sample with the lowest (0.001%) Fe doping, and it showed a rapid downward trend with increasing Fe doping. Majority of the Fe ions are in 3+ oxidation state occupying octahedral sites. Another significant fraction of Fe dopant ions is in 4+ oxidation state and a still smaller fraction might be existing as Fe{sup 2+} ions, both occupying distorted sites, presumably in the surface regions of the nanocrystals, near oxygen vacancies. These studies also suggest that the observed magnetism is not due to exchange coupling between Fe{sup 3+} spins. A more probable role for the multi-valent Fe ions may be to act as charge reservoirs, leading to charge transfer ferromagnetism.

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

Towards 100Sn with GASP + Si-ball + Recoil Mass Spectrometer: High-spin states of 105Sn and 103In

International Nuclear Information System (INIS)

De Angelis, G.; Farnea, E.; Gadea, A.; Sferrazza, M.; Ackermann, D.; Bazzacco, D.; Bednarczyk, P.; Bizzeti, P.G.; Bizzeti Sona, A.M.; Brandolini, F.; Burch, R.; Buscemi, A.; De Acuna, D.; De Poli, M.; Fahlander, C.; Li, Y.; Lipoglavsek, M.; Lunardi, S.; Makishima, A.; Menegazzo, R.; Mueller, L.; Napoli, D.; Ogawa, M.; Pavan, P.; Rossi-Alvarez, C.; Scarlassara, F.; Segato, G.F.; Seweryniak, D.; Soramel, F.; Spolaore, P.; Zanon, R.

1995-01-01

Very proton rich nuclei in the A∼100 region have been investigated using the GASP array coupled with the Recoil Mass Spectrometer (RMS) and the GASP Si-ball. High-spin states of 105 Sn and 103 In nuclei formed with the reaction 58 Ni+ 50 Cr at 210MeV have been investigated up to similar 10 and 7MeV of excitation energy respectively. We have confirmed the known excited states for both nuclei and extended to higher spin the level scheme. The experimental level schemes are compared with shell model calculations. ((orig.))

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

Usb1 controls U6 snRNP assembly through evolutionarily divergent cyclic phosphodiesterase activities.

Science.gov (United States)

Didychuk, Allison L; Montemayor, Eric J; Carrocci, Tucker J; DeLaitsch, Andrew T; Lucarelli, Stefani E; Westler, William M; Brow, David A; Hoskins, Aaron A; Butcher, Samuel E

2017-09-08

U6 small nuclear ribonucleoprotein (snRNP) biogenesis is essential for spliceosome assembly, but not well understood. Here, we report structures of the U6 RNA processing enzyme Usb1 from yeast and a substrate analog bound complex from humans. Unlike the human ortholog, we show that yeast Usb1 has cyclic phosphodiesterase activity that leaves a terminal 3' phosphate which prevents overprocessing. Usb1 processing of U6 RNA dramatically alters its affinity for cognate RNA-binding proteins. We reconstitute the post-transcriptional assembly of yeast U6 snRNP in vitro, which occurs through a complex series of handoffs involving 10 proteins (Lhp1, Prp24, Usb1 and Lsm2-8) and anti-cooperative interactions between Prp24 and Lhp1. We propose a model for U6 snRNP assembly that explains how evolutionarily divergent and seemingly antagonistic proteins cooperate to protect and chaperone the nascent snRNA during its journey to the spliceosome.The mechanism of U6 small nuclear ribonucleoprotein (snRNP) biogenesis is not well understood. Here the authors characterize the enzymatic activities and structures of yeast and human U6 RNA processing enzyme Usb1, reconstitute post-transcriptional assembly of yeast U6 snRNP in vitro, and propose a model for U6 snRNP assembly.

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...

Facet-controlled synthesis and facet-dependent photocatalytic properties of SnO{sub 2} micropolyhedrons

Energy Technology Data Exchange (ETDEWEB)

Zhou, Gengxia [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Wu, Xinglong, E-mail: hkxlwu@nju.edu.cn [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Liu, Lizhe; Zhu, Xiaobin [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Zhu, Xiaoshu [Center for Analysis and Testing, Nanjing Normal University, Nanjing 210093 (China); Hao, Yanling [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-09-15

Graphical abstract: - Highlights: • SnO{sub 2} micropolyhedrons with (1 0 1) and (1 0 0) facets at different ratios are fabricated. • The vapor–solid growth mechanism of micropolyhedrons is discussed. • SnO{sub 2} octahedrons with complete (1 0 1) facets show strong photocatalytic activity. • Enhanced photocatalytic activity stems from the facet-dependent surface states. - Abstract: The facet-dependent properties of SnO{sub 2} are of fundamental and practical importance. In this study, by adjusting the deposition temperature during chemical vapor deposition, octahedral SnO{sub 2} with the exposed (1 0 1) facet and two other kinds of SnO{sub 2} polyhedrons with (1 0 1) and (1 0 0) facets with different ratios are fabricated controllably based on the vapor–solid growth mechanism. A slight increase in the deposition temperature from 1030 to 1070 °C decreases the surface energy of the reduced (1 0 1) facet with Sn termination, leading to the formation of polyhedrons with different area ratios of (1 0 1) to (1 0 0) facets. By adopting the terephthalic acid fluorescent method, the SnO{sub 2} octahedrons are demonstrated to have the strongest photocatalytic activity due to the formation of surface states induced by 5s electrons of bivalent Sn on the (1 0 1) surface. The results reveal that the photocatalytic properties of SnO{sub 2} microcrystals can be enhanced by facet-controlled synthesis.

Structure and magnetic properties of Sm{sub 2}Rh{sub 3}Sn{sub 5}. An intergrowth of TiNiSi- and NdRh{sub 2}Sn{sub 4}-related slabs

Energy Technology Data Exchange (ETDEWEB)

Heying, Birgit; Koesters, Jutta; Hoffmann, Rolf-Dieter; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2017-07-01

The stannide Sm{sub 2}Rh{sub 3}Sn{sub 5} was obtained by arc-melting of the elements and subsequent annealing at 1070 K in a silica tube. Sm{sub 2}Rh{sub 3}Sn{sub 5} crystallizes with the orthorhombic Y{sub 2}Rh{sub 3}Sn{sub 5} type structure, space group Cmc2{sub 1}, Z=4: a=444.46(8), b=2636.2(4), c=718.3(1) pm, wR=0.0711, 1761 F{sup 2} values and 61 variables. The three crystallographically independent rhodium atoms show tricapped trigonal prismatic coordination by samarium and tin atoms. Sm{sub 2}Rh{sub 3}Sn{sub 5} can be considered as a simple 1:1 intergrowth structure of TiNiSi- and NdRh{sub 2}Sn{sub 4}-related slabs of compositions SmRhSn and SmRh{sub 2}Sn{sub 4}. Temperature dependent magnetic susceptibility data revealed van Vleck type behavior caused by the proximity of the exited {sup 6}H{sub 7/2} state to the {sup 6}H{sub 5/2} ground state of Sm{sup 3+}, and an antiferromagnetic ordering occurs at T{sub N}=3.5(5) K.

Phase transition temperature in the Zr-rich corner of Zr-Nb-Sn-Fe alloys

Science.gov (United States)

Canay, M.; Danón, C. A.; Arias, D.

2000-08-01

The influence of small composition changes on the phase transformation temperature of Zr-1Nb-1Sn-0.2(0.7)Fe alloys was studied in the present work, by electrical resistivity measurements and metallographic techniques. For the alloy with 0.2 at.% Fe we have determined Tα↔α+β=741°C and Tα+β↔β=973°C, and for the 0.7 at.% Fe the transformation temperatures were T α↔α+β=712°C and T α+β↔β=961°C. We have verified that the addition of Sn stabilized the β phase.

SDF1-CXCR4 Signaling Contributes to the Transition from Acute to Chronic Pain State.

Science.gov (United States)

Yang, Fei; Sun, Wei; Luo, Wen-Jun; Yang, Yan; Yang, Fan; Wang, Xiao-Liang; Chen, Jun

2017-05-01

Emerging evidence has demonstrated the involvement of stromal cell-derived factor 1 (SDF1, also known as CXCL12)-CXCR4 signaling in a variety of pain state. However, the underlying mechanisms of SDF1-CXCR4 signaling leading to the maintenance of chronic pain states are poorly understood. In the present study, we sought to explore the role of SDF1-CXCR4 signaling in the forming of neuroplasticity by applying a model of the transition from acute to chronic pain state, named as hyperalgesic priming. Utilizing intraplantar bee venom (BV) injection, we successfully established hyperalgesic priming state and found that peripheral treating with AMD3100, a CXCR4 antagonist, or knocking down CXCR4 by intraganglionar CXCR4 small interfering RNA (siRNA) injection could prevent BV-induced primary mechanical hyperalgesia and hyperalgesic priming. Moreover, we showed that single intraplantar active SDF1 protein injection is sufficient to induce acute mechanical hyperalgesia and hyperalgesic priming through CXC4. Intraplantar coinjection of ERK inhibitor, U0126, and PI3K inhibitor, LY294002, as well as two protein translation inhibitors, temsirolimus and cordycepin, prevented the development of SDF1-induced acute mechanical hyperalgesia and hyperalgesic priming. Finally, on the models of complete Freund's adjuvant (CFA)-induced chronic inflammatory pain and spared nerve injury (SNI)-induced chronic neuropathic pain, we observed that knock-down of CXCR4 could both prevent the development and reverse the maintenance of chronic pain state. In conclusion, our present data suggested that through regulating ERK and PI3K-AKT pathways-mediated protein translation SDF1-CXCR4 signaling mediates the transition from acute pain to chronic pain state and finally contributes to the development and maintenance of chronic pain.

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.)

Theoretical evidence of PtSn alloy efficiency for CO oxidation.

Science.gov (United States)

Dupont, Céline; Jugnet, Yvette; Loffreda, David

2006-07-19

The efficiency of PtSn alloy surfaces toward CO oxidation is demonstrated from first-principles theory. Oxidation kinetics based on atomistic density-functional theory calculations shows that the Pt3Sn surface alloy exhibits a promising catalytic activity for fuel cells. At room temperature, the corresponding rate outstrips the activity of Pt(111) by several orders of magnitude. According to the oxidation pathways, the activation barriers are actually lower on Pt3Sn(111) and Pt3Sn/Pt(111) surfaces than on Pt(111). A generalization of Hammer's model is proposed to elucidate the key role of tin on the lowering of the barriers. Among the energy contributions, a correlation is evidenced between the decrease of the barrier and the strengthening of the attractive interaction energy between CO and O moieties. The presence of tin modifies also the symmetry of the transition states which are composed of a CO adsorbate on a Pt near-top position and an atomic O adsorption on an asymmetric mixed PtSn bridge site. Along the reaction pathways, a CO2 chemisorbed surface intermediate is obtained on all the surfaces. These results are supported by a thorough vibrational analysis including the coupling with the surface phonons which reveals the existence of a stretching frequency between the metal substrate and the CO2 molecule.

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.

Effect of strain on the martensitic phase transition in superconducting Nb3Sn

International Nuclear Information System (INIS)

Hoard, R.W.; Scanlan, R.M.; Smith, G.S.; Farrell, C.L.

1980-01-01

The connection between the cubic-to-tetragonal martensitic phase transformation and the phenomenon of superconductivity in A15 compounds is being investigated. The degradation of the critical parameters, such as T/sub c/, H/sub c2/, and J/sub c/, with mechanical straining is of particular interest. Low-temperature x-ray diffraction experiments are performed on Nb 3 Sn ribbons (with the bronze layers etched off) mounted on copper and indium sample stages. The cryostat used is unique in that it has a vacuum mechanical insert which allows the superconductor to be placed under both compressive and tensile strains while at low temperatures. Preliminary results indicate that the martensitic phase transition temperature, T/sub m/, increases with compressive strains. Other effects of strain on tetragonal phase production are also discussed

Pressure effects on topological crystalline insulator SnTe and derived superconductor Sn{sub 0.5}In{sub 0.5}Te

Energy Technology Data Exchange (ETDEWEB)

Maurya, V. K.; Shruti,; Patnaik, S., E-mail: spatnaik@mail.jnu.ac.in [School of Physical Sciences, Jawaharlal Nehru University New Delhi (India); Jha, Rajveer; Awana, V. P. S. [National Physical Laboratory, New Delhi 110012 (India)

2016-05-23

We are reporting decrease in superconducting transition temperature accompanied by increased metallicity in indium doped SnTe superconductor. SnTe is a topological crystalline insulator and superconductivity is achieved by indium substitution in place of tin. With application of hydrostatic pressure we find negative dT{sub c}/dP of ~ -0.6K/GPa upto 2.5 GPa. The overall phenomenon is ascribed to unconventional superconductivity. Decrease in resistivity is also seen in single crystal SnTe with application of pressure but no evidence of superconductivity is observed.

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

International Nuclear Information System (INIS)

Huang, Y.J.; Shen, J.; Sun, J.F.; Yu, X.B.

2007-01-01

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti 41.5 Zr 2.5 Hf 5 Cu 42.5-x Ni 7.5 Si 1 Sn x (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy. The activation energies for glass transition and crystallization for Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy also possesses superior mechanical properties

Bottomonium spectroscopy and radiative transitions involving the chi(bJ)(1P, 2P) states at BABAR

NARCIS (Netherlands)

Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Schroeder, T.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Lankford, A. J.; Mandelkern, M.; Dey, B.; Gary, J. W.; Long, O.; Campagnari, C.; Sevilla, M. Franco; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Lockman, W. S.; Vazquez, W. Panduro; Schumm, B. A.; Seiden, A.; Chao, D. S.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Miyashita, T. S.; Ongmongkolkul, P.; Roehrken, M.; Andreassen, R.; Huard, Z.; Meadows, B. T.; Pushpawela, B. G.; Sokoloff, M. D.; Sun, L.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Bernard, D.; Verderi, M.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Piemontese, L.; Santoro, V.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Martellotti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Adametz, A.; Uwer, U.; Lacker, M.; Dauncey, P. D.; Mallik, U.; Cochran, J.; Prell, S.; Ahmed, H.; Gritsan, A. V.; Arnaud, N.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Cowan, G.; Bougher, J.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Schubert, K. R.; Barlow, R. J.; Lafferty, G. D.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Cowan, R.; Sciolla, G.; Cheaib, R.; Patel, P. M.; Robertson, S. H.; Neri, N.; Palombo, F.; Cremaldi, L.; Godang, R.; Sonnek, P.; Summers, D. J.; Simard, M.; Taras, P.; De Nardo, G.; Onorato, G.; Sciacca, C.; Martinelli, M.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Honscheid, K.; Kass, R.; Feltresi, E.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Biasini, M.; Manoni, E.; Pacetti, S.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Chrzaszcz, M.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Perez, A.; Rizzo, G.; Walsh, J. J.; Pegna, D. Lopes; Olsen, J.; Smith, A. J. S.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Gioi, L. Li; Pilloni, A.; Piredda, G.; Buenger, C.; Dittrich, S.; Gruenber, O.; Hess, M.; Leddig, T.; Voss, C.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Vasseur, G.; Anulli, F.; Aston, D.; Bard, D. J.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Fulsom, B. G.; Graham, M. T.; Hast, C.; Innes, W. R.; Kim, P.; Leith, D. W. G. S.; Lewis, P.; Lindemann, D.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Va'vra, J.; Wisniewski, W. J.; Wulsin, H. W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Spanier, S. M.; Ritchie, J. L.; Ruland, A. M.; Schwitters, R. F.; Wray, B. C.; Izen, J. M.; Lou, X. C.; Bianchi, F.; De Mori, F.; Filippi, A.; Gamba, D.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Villanueva-Perez, P.; Albert, J.; Banerjee, Sw.; Beaulieu, A.; Bernlochner, F. U.; Choi, H. H. F.; Kowalewski, R.; Lewczuk, M. J.; Lueck, T.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Band, H. R.; Dasu, S.; Pan, Y.; Prepost, R.

2014-01-01

We use (121±1) million Υ(3S) and (98±1) million Υ(2S) mesons recorded by the BABAR detector at the PEP-II e+e− collider at SLAC to perform a study of radiative transitions involving the χbJ(1P,2P) states in exclusive decays with μ+μ−γγ final states. We reconstruct twelve channels in four cascades

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.

STOREKEEPER RELATED1/G-Element Binding Protein (STKR1) Interacts with Protein Kinase SnRK11[OPEN

Science.gov (United States)

Nietzsche, Madlen; Guerra, Tiziana; Fernie, Alisdair R.

2018-01-01

Sucrose nonfermenting related kinase1 (SnRK1) is a conserved energy sensor kinase that regulates cellular adaptation to energy deficit in plants. Activation of SnRK1 leads to the down-regulation of ATP-consuming biosynthetic processes and the stimulation of energy-generating catabolic reactions by transcriptional reprogramming and posttranslational modifications. Although considerable progress has been made during the last years in understanding the SnRK1 signaling pathway, many of its components remain unidentified. Here, we show that the catalytic α-subunits KIN10 and KIN11 of the Arabidopsis (Arabidopsis thaliana) SnRK1 complex interact with the STOREKEEPER RELATED1/G-Element Binding Protein (STKR1) inside the plant cell nucleus. Overexpression of STKR1 in transgenic Arabidopsis plants led to reduced growth, a delay in flowering, and strongly attenuated senescence. Metabolite profiling revealed that the transgenic lines exhausted their carbohydrates during the dark period to a greater extent than the wild type and accumulated a range of amino acids. At the global transcriptome level, genes affected by STKR1 overexpression were broadly associated with systemic acquired resistance, and transgenic plants showed enhanced resistance toward a virulent strain of the biotrophic oomycete pathogen Hyaloperonospora arabidopsidis Noco2. We discuss a possible connection of STKR1 function, SnRK1 signaling, and plant immunity. PMID:29192025

Microstructure, Tensile Properties, and Corrosion Behavior of Die-Cast Mg-7Al-1Ca- xSn Alloys

Science.gov (United States)

Wang, Feng; Dong, Haikuo; Sun, Shijie; Wang, Zhi; Mao, Pingli; Liu, Zheng

2018-02-01

The microstructure, tensile properties, and corrosion behavior of die-cast Mg-7Al-1Ca- xSn ( x = 0, 0.5, 1.0, and 2.0 wt.%) alloys were studied using OM, SEM/EDS, tensile test, weight loss test, and electrochemical test. The experimental results showed that Sn addition effectively refined grains and intermetallic phases and increased the amount of intermetallic phases. Meanwhile, Sn addition to the alloys suppressed the formation of the (Mg,Al)2Ca phase and resulted in the formation of the ternary CaMgSn phase and the binary Mg2Sn phase. The Mg-7Al-1Ca-0.5Sn alloy exhibited best tensile properties at room temperature, while Mg-7Al-1Ca-1.0Sn alloy exhibited best tensile properties at elevated temperature. The corrosion resistance of studied alloys was improved by the Sn addition, and the Mg-7Al-1Ca-0.5Sn alloy presented the best corrosion resistance.

Study of 4f hybridization in CeNiX with X=SnδGe1-δ, 0≤δ≤1

International Nuclear Information System (INIS)

Fuente, C. de la; Moral, A. del; Adroja, D.T.; Fraile, A.; Arnaudas, J.I.

2010-01-01

We report inelastic neutron scattering and core-level X-ray photoemission spectroscopy experiments for studying the Kondo problem in the CeNiX, X=Sn δ Ge 1-δ 0≤δ≤1 series. The neutron results confirm that they behave like a Kondo lattice for δ≥0.85, showing broad maxima at around 30 meV, typical of a crystal field magnetic scattering. So, the Ge doping could produce the suppression of the cerium magnetism observed for δ≤0.25. To open a more deep sight on this point, we have analyzed the 3d core-level XPS spectra by using the well-known Gunnarsson-Schoenhammer model. From this analysis, we have obtained the 'on-site' Coulomb bare repulsion for f states, U, and hybridization parameter, Δ, related with the hopping from the f states to the conduction ones. These U values are very similar for all compounds, about 7 eV, but the hybridization parameter slightly changes from 0.2 to 0.16 eV on increasing the Sn concentration. In Sn-rich compounds, the 4f occupation is close to spin limit fluctuation, which allows us to obtain an estimation of the Kondo temperatures, ∼1200 K, and the static 0 K susceptibility, ∼1.1x10 -3 emu/mol. Finally, we have done 'ab-initio' calculations based on the LDA+U+SO which confirm the existence of a small electronic gap opening in the DOS of Ge-rich compounds for U values lower than 7 eV.

Description of strong M1 transitions between 4^+ states at N=52 within the sdg-IBM-2

Science.gov (United States)

Casperson, R. J.; Werner, V.; Heinze, S.

2009-10-01

The interplay between collective and single-particle degrees of freedom for nuclei near the N=50 shell closure have recently been under investigation. In Molybdenum and Ruthenium nuclei, collective symmetric and mixed-symmetric structures have been identified, while in Zirconium, underlying shell-structure plays an enhanced role. The one-phonon 2^+ mixed-symmetry state was identified from its strong M1 transition to the 2^+1 state. Similar transitions were observed between 4^+ states in ^94Mo and ^92Zr, and shell model calculations indicate that hexadecapole excitations play a role. These phenomena will be investigated within the sdg-Interacting Boson Model-2 in order to gain a better understanding about the structure of the states involved, and to which extent the hexadecapole degree of freedom is important at relatively low energies. First calculations within this model, using an F-spin conserving Hamiltonian to disentangle symmetric and mixed- symmetric structures, will be presented and compared to data.

Designed hybrid nanostructure with catalytic effect: beyond the theoretical capacity of SnO2 anode material for lithium ion batteries

OpenAIRE

Wang, Ye; Huang, Zhi Xiang; Shi, Yumeng; Wong, Jen It; Ding, Meng; Yang, Hui Ying

2015-01-01

Transition metal cobalt (Co) nanoparticle was designed as catalyst to promote the conversion reaction of Sn to SnO2 during the delithiation process which is deemed as an irreversible reaction. The designed nanocomposite, named as SnO2/Co3O4/reduced-graphene-oxide (rGO), was synthesized by a simple two-step method composed of hydrothermal (1st step) and solvothermal (2nd step) synthesis processes. Compared to the pristine SnO2/rGO and SnO2/Co3O4 electrodes, SnO2/Co3O4/rGO nanocomposites exhibi...

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

The pure rotational spectra of the open-shell diatomic molecules PbI and SnI

Energy Technology Data Exchange (ETDEWEB)

Evans, Corey J., E-mail: cje8@le.ac.uk, E-mail: nick.walker@newcastle.ac.uk; Needham, Lisa-Maria E. [Department of Chemistry, University of Leicester, Leicester LE1 7RH (United Kingdom); Walker, Nicholas R., E-mail: cje8@le.ac.uk, E-mail: nick.walker@newcastle.ac.uk; Köckert, Hansjochen; Zaleski, Daniel P.; Stephens, Susanna L. [School of Chemistry, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

2015-12-28

Pure rotational spectra of the ground electronic states of lead monoiodide and tin monoiodide have been measured using a chirped pulsed Fourier transform microwave spectrometer over the 7-18.5 GHz region for the first time. Each of PbI and SnI has a X {sup 2}Π{sub 1/2} ground electronic state and may have a hyperfine structure that aids the determination of the electron electric dipole moment. For each species, pure rotational transitions of a number of different isotopologues and their excited vibrational states have been assigned and fitted. A multi-isotopologue Dunham-type analysis was carried out on both species producing values for Y{sub 01}, Y{sub 02}, Y{sub 11}, and Y{sub 21}, along with Λ-doubling constants, magnetic hyperfine constants and nuclear quadrupole coupling constants. The Born-Oppenheimer breakdown parameters for Pb have been evaluated and the parameter rationalized in terms of finite nuclear field effects. Analysis of the bond lengths and hyperfine interaction indicates that the bonding in both PbI and SnI is ionic in nature. Equilibrium bond lengths have been evaluated for both species.

THE 2012 RISE OF THE REMARKABLE TYPE IIn SN 2009ip

International Nuclear Information System (INIS)

Prieto, José L.; Brimacombe, J.; Drake, A. J.; Howerton, S.

2013-01-01

Recent observations by Mauerhan et al. have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN explosion. We present ∼100 optical R- and I-band photometric measurements of SN 2009ip obtained between UT 2012 September 23.6 and October 9.6, using 0.3-0.4 m aperture telescopes from the Coral Towers Observatory in Cairns, Australia. The light curves show well-defined phases, including very rapid brightening early on (0.5 mag in 6 hr observed during the night of September 24), a transition to a much slower rise between September 25 and September 28, and a plateau/peak around October 7. These changes are coincident with the reported spectroscopic changes that most likely mark the start of a strong interaction between the fast SN ejecta and a dense circumstellar medium formed during the LBV eruptions observed in recent years. In the 16-day observing period, SN 2009ip brightened by 3.7 mag from I = 17.4 mag on September 23.6 (M I ≅ –14.2) to I = 13.7 mag (M I ≅ –17.9) on October 9.6, radiating ∼3 × 10 49 erg in the optical wavelength range. As of 2012 October 9.6, SN 2009ip is more luminous than most Type IIP SN and comparable to other Type IIn SN.

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

Influence of substrate material on the microstructure and optical properties of hot wall deposited SnS thin films

International Nuclear Information System (INIS)

Bashkirov, S.A.; Gremenok, V.F.; Ivanov, V.A.; Shevtsova, V.V.; Gladyshev, P.P.

2015-01-01

Tin monosulfide SnS raises an interest as a promising material for photovoltaics. The influence of the substrate material on the microstructure and optical properties of SnS thin films with [111] texture obtained by hot wall vacuum deposition on glass, molybdenum and indium tin oxide substrates is reported. The lattice parameters for layers grown on different substrates were determined by X-ray diffraction and their deviations from the data reported in the literature for single α-SnS crystals were discussed. The change in the degree of preferred orientation of the films depending on the substrate material is observed. The direct nature of the optical transitions with the optical band gap of 1.15 ± 0.01 eV is reported. - Highlights: • SnS thin films were hot wall deposited on glass, molybdenum and indium tin oxide. • Physical properties of the films were studied with respect to the substrate type. • The SnS lattice parameter deviations were observed and the explanation was given. • The direct optical transitions with the band gap of 1.15 ± 0.01 eV were observed

μSR and NMR study of the superconducting Heusler compound YPd2Sn

Science.gov (United States)

Saadaoui, H.; Shiroka, T.; Amato, A.; Baines, C.; Luetkens, H.; Pomjakushina, E.; Pomjakushin, V.; Mesot, J.; Pikulski, M.; Morenzoni, E.

2013-09-01

We report on muon-spin rotation and relaxation (μSR) and 119Sn nuclear magnetic resonance (NMR) measurements to study the microscopic superconducting and magnetic properties of the Heusler compound with the highest superconducting transition temperature, YPd2Sn (Tc=5.4 K). Measurements in the vortex state provide the temperature dependence of the effective magnetic penetration depth λ(T) and the field dependence of the superconducting gap Δ(0). The results are consistent with a very dirty s-wave BCS superconductor with a gap Δ(0)=0.85(3) meV, λ(0)=212(1) nm, and a Ginzburg-Landau coherence length ξGL(0)≅23 nm. In spite of its very dirty character, the effective density of condensed charge carriers is high compared to that in the normal state. The μSR data in a broad range of applied fields are well reproduced by taking into account a field-related reduction of the effective superconducting gap. Zero-field μSR measurements, sensitive to the possible presence of very small magnetic moments, do not show any indications of magnetism in this compound.

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.

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

Ionic Liquid-Assisted Synthesis of Nanoscale (MoS2)x(SnO2)1-x on Reduced Graphene Oxide for the Electrocatalytic Hydrogen Evolution Reaction.

Science.gov (United States)

Ravula, Sudhir; Zhang, Chi; Essner, Jeremy B; Robertson, J David; Lin, Jian; Baker, Gary A

2017-03-08

Layered transition metal dichalcogenides (TMDs) have attracted increased attention due to their enhanced hydrogen evolution reaction (HER) performance. More specifically, ternary TMD nanohybrids, such as MoS 2(1-x) Se 2x or bimetallic sulfides, have arisen as promising electrocatalysts compared to MoS 2 and MoSe 2 due to their electronic, morphologic, and size tunabilities. Herein, we report the successful synthesis of few-layered MoS 2 /rGO, SnS 2 /rGO, and (MoS 2 ) x (SnO 2 ) 1-x /rGO nanohybrids anchored on reduced graphene oxide (rGO) through a facile hydrothermal reaction in the presence of ionic liquids as stabilizing, delayering agents. Spectroscopic and microscopic techniques (electron microscopy, X-ray diffraction, Raman spectroscopy, neutron activation analysis, and UV-vis spectrophotometry) are used to validate the hierarchical properties, phase identity, and the smooth compositional tunability of the (MoS 2 ) x (SnO 2 ) 1-x /rGO nanohybrids. Linear sweep voltammetry measurements reveal that incorporation of Sn into the ternary nanohybrids (as a discrete SnO 2 phase) greatly reduces the overpotential by 90-130 mV relative to the MoS 2 electrocatalyst. Significantly, the (MoS 2 ) 0.6 (SnO 2 ) 0.4 /rGO nanohybrid displays superior catalytic performance over MoS 2 alone, exhibiting a low overpotential (η 10 ) of 263 ± 5 mV and a small Tafel slope of 50.8 mV dec -1 . The hybrid catalyst shows high stability for the HER in acidic solutions, with negligible activity loss after 1000 cycles. The hierarchical structures and large surface areas possessing exposed, active edge sites make few-layered (MoS 2 ) x (SnO 2 ) 1-x /rGO nanohybrids promising nonprecious metal electrocatalysts for the HER.

Gamma-line intensity difference method for sup 1 sup 1 sup 7 sup m Sn at high resolution

CERN Document Server

Remeikis, V; Mazeika, K

1998-01-01

The method for detection of small differences in the gamma-spectrum line intensity for the radionuclide in different environments has been developed for measurements at high resolution. The experiments were realized with the pure germanium planar detector. Solution of the methodical problems allowed to measure the relative difference DELTA IOTA subgamma/IOTA subgamma=(3.4+-1.5)*10 sup - sup 4 of the sup 1 sup 1 sup 7 sup m Sn 156.02 keV gamma-line intensity for the radionuclide in SnO sub 2 with respect to SnS from the difference in the gamma-spectra. The error of the result is caused mainly by the statistical accuracy. It is limited by the highest counting rate at sufficiently high energy resolution and relatively short half-life of sup 1 sup 1 sup 7 sup m Sn. (author)

Spin-State Transition in La1-xSrxCoO3 Single Crystals

Science.gov (United States)

Bhardwaj, S.; Prabhakaran, D.; Awasthi, A. M.

2011-07-01

We present a study of the thermal conductivity (κ), specific heat (Cp) and Raman spectra of La1-xSrxCoO3 (x = 0,0.1) single crystals. Both the specimens have low thermal conductivity and board Raman peaks, arising from strong scattering of phonons by lattice disorder, produced by (and doping-enhanced) spin-states admixture of the Co3+ ions. The thermal conductivity anomalously deviates from ˜1/T behaviour at high (room) temperatures, expected of an insulator. High-temperature specific heat reveals large decrease in the metal-insulator (M-I) transition temperature with Sr-doping.

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.

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.)

Ab initio study of native defects in SnO under strain

KAUST Repository

Bianchi Granato, Danilo

2014-04-01

Tin monoxide (SnO) has promising properties to be applied as a p-type semiconductor in transparent electronics. To this end, it is necessary to understand the behaviour of defects in order to control them. We use density functional theory to study native defects of SnO under tensile and compressive strain. We show that Sn vacancies are less stable under tension and more stable under compression, irrespectively of the charge state. In contrast, O vacancies behave differently for different charge states. It turns out that the most stable defect under compression is the +1 charged O vacancy in an Sn-rich environment and the charge neutral O interstitial in an O-rich environment. Therefore, compression can be used to transform SnO from a p-type into either an n-type or an undoped semiconductor. Copyright © EPLA, 2014.

Theory of optical transitions in conjugated polymers. I. Ideal systems.

Science.gov (United States)

Barford, William; Marcus, Max

2014-10-28

We describe a theory of linear optical transitions in conjugated polymers. The theory is based on three assumptions. The first is that the low-lying excited states of conjugated polymers are Frenkel excitons coupled to local normal modes, described by the Frenkel-Holstein model. Second, we assume that the relevant parameter regime is ℏω ≪ J, i.e., the adiabatic regime, and thus the Born-Oppenheimer factorization of the electronic and nuclear degrees of freedom is generally applicable. Finally, we assume that the Condon approximation is valid, i.e., the exciton-polaron wavefunction is essentially independent of the normal modes. Using these assumptions we derive an expression for an effective Huang-Rhys parameter for a chain (or chromophore) of N monomers, given by S(N) = S(1)/IPR, where S(1) is the Huang-Rhys parameter for an isolated monomer. IPR is the inverse participation ratio, defined by IPR = (∑(n)|Ψ(n)|(4))(-1), where Ψ(n) is the exciton center-of-mass wavefunction. Since the IPR is proportional to the spread of the exciton center-of-mass wavefunction, this is a key result, as it shows that S(N) decreases with chain length. As in molecules, in a polymer S(N) has two interpretations. First, ℏωS(N) is the relaxation energy of an excited state caused by its coupling to the normal modes. Second, S(N) appears in the definition of an effective Franck-Condon factor, F(0v)(N) = S(N)(v)exp ( - S(N))/v! for the vth vibronic manifold. We show that the 0 - 0 and 0 - 1 optical intensities are proportional to F00(N) and F01(N), respectively, and thus the ratio of the 0 - 1 to 0 - 0 absorption and emission intensities are proportional to S(N). These analytical results are checked by extensive DMRG calculations and found to be generally valid, particularly for emission. However, for large chain lengths higher-lying quasimomentum exciton states become degenerate with the lowest vibrational excitation of the lowest exciton state. When this happens there is

Influence of adding BaSnO3 nanoparticles on magnetic transport properties for CuTl-1223 phase

Directory of Open Access Journals (Sweden)

M.ME. Barakat

Full Text Available Co-precipitation method and solid-state reaction technique were used to synthesize BaSnO3 nanoparticles and (BaSnO3x/Cu0.5Tl0.5Ba2Ca2Cu3O10−δ samples, 0.00 ≤ x ≤ 1.50 wt%, respectively. All samples were characterized using X-ray powder diffraction (XRD and electrical resistivity measurements at different applied DC magnetic fields ranged from 0.29 to 4.40 kG. The relative volume fraction, superconducting transition temperature, Tc, and hole carriers concentration, P, were enhanced by increasing x up to 0.25 wt%, beyond which they were decreased for further increase in the addition of BaSnO3 nanoparticles. Both thermally activated flux creep (TAFC model and Ambegaokar and Halperin (AH theory were used to analyze the magnetoresistance data for (BaSnO3x/CuTl-1223 samples. An enhancement in the derived magnetic superconducting parameters, including the flux pinning energy, U, critical current density, Jc(0, and upper critical magnetic field, Bc2(0, as well as a decrement in the coherence length at 0 K, ξ(0, was achieved by adding BaSnO3 nanoparticles up to 0.25 wt%. A reverse trend was recorded for further addition of BaSnO3 nanoparticles. The electronic thermal conductivity, κe, was decreased by increasing applied magnetic fields below Tc. Keywords: CuTl-1223 phase, BaSnO3 nanoparticles, Flux pinning energy, Critical current density

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)

Cerium valence change in the solid solutions Ce(Rh1-xRux)Sn

International Nuclear Information System (INIS)

Niehaus, Oliver; Riecken, Jan F.; Winter, Florian; Poettgen, Rainer; Muenster Univ.; Abdala, Paula M.; Chevalier, Bernard

2013-01-01

The solid solutions Ce(Rh 1-x Ru x )Sn were investigated by means of susceptibility measurements, specific heat, electrical resistivity, X-ray absorption spectroscopy (XAS), and 119 Sn Moessbauer spectroscopy. Magnetic measurements as well as XAS data show a cerium valence change in dependence on the ruthenium content. Higher ruthenium content causes an increase from 3.22 to 3.45 at 300 K. Furthermore χ and χ -1 data indicate valence fluctuation for cerium as a function of temperature. For example, Ce(Rh 0.8 Ru 0.2 )Sn exhibits valence fluctuations between 3.42 and 3.32 in the temperature range of 10 to 300 K. This could be proven by using the interconfiguration fluctuation (ICF) model introduced by Sales and Wohlleben. Cerium valence change does not influence the tin atoms as proven by 119 Sn Moessbauer spectroscopy, but it influences the electrical properties. Ce(Rh 0.9 Ru 0.1 )Sn behaves like a typical valence fluctuating compound, and higher ruthenium content causes an increase of the metallic behavior. (orig.)

Electron Excitation Rate Coefficients for Transitions from the IS21S Ground State to the 1S2S1,3S and 1S2P1,3P0 Excited States of Helium

Science.gov (United States)

Aggarwal, K. M.; Kingston, A. E.; McDowell, M. R. C.

1984-03-01

The available experimental and theoretical electron impact excitation cross section data for the transitions from the 1s2 1S ground state to the 1s2s 1,3S and 1s2p 1,3P0 excited states of helium are assessed. Based on this assessed data, excitation rate coefficients are calculated over a wide electron temperature range below 3.0×106K. A comparison with other published results suggests that the rates used should be lower by a factor of 2 or more.

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.

Coulomb excitation of neutron-rich $^{134-136}$Sn isotopes

CERN Multimedia

We propose to study excited states in the isotopes $^{134,136}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to investigate the evolution of quadrupole collectivity beyond the magic shell closure at N = 82 by the determination of B(E2) values and electric quadrupole moments $\\mathcal{Q}_2$. Recent shell-model calculations using realistic interactions predict possible enhanced collectivity in neutron-rich regions. Evidence for this could be obtained by this experiment. Furthermore, the currently unknown excitation energies of the 2$^+_{1}$ and 4$^+_{1}$ states in $^{136}$Sn will be measured for the first time.

Electro-caloric effect in lead-free Sn doped BaTiO3 ceramics at room temperature and low applied fields

International Nuclear Information System (INIS)

Upadhyay, Sanjay Kumar; Reddy, V. Raghavendra; Bag, Pallab; Rawat, R.; Gupta, S. M.; Gupta, Ajay

2014-01-01

Structural, dielectric, ferroelectric (FE), 119 Sn Mössbauer, and specific heat measurements of polycrystalline BaTi 1–x Sn x O 3 (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and 119 Sn Mössbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ≥ 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

Structural, electronic, optical and thermoelectric investigations of antiperovskites A3SnO (A = Ca, Sr, Ba) using density functional theory

Science.gov (United States)

Hassan, M.; Shahid, A.; Mahmood, Q.

2018-02-01

Density functional theory study of the structural, electrical, optical and thermoelectric behaviors of very less investigated anti-perovskites A3SnO (A = Ca, Sr, Ba) is performed with FP-LAPW technique. The A3SnO exhibit narrow direct band gap, in contrast to the wide indirect band gap of the respective perovskites. Hence, indirect to direct band gap transformation can be realized by the structural transition from perovskite to anti-perovskite. The p-p hybridization between A and O states result in the covalent bonding. The transparency and maximum reflectivity to the certain energies, and the verification of the Penn's model indicate potential optical device applications. Thermoelectric behaviors computed within 200-800 K depict that Ca3SnO exhibits good thermoelectric performance than Ba3SnO and Sr3SnO, and all three operate at their best at 800 K suggesting high temperature thermoelectric device applications.

Nuclear spectroscopy study of the 117 Sn by the angular correlation technique

International Nuclear Information System (INIS)

Borges, Joao Baptista

1977-01-01

The directional correlation of gamma cascade (553-159) keV populated in 117 Sn through the β - decay of 117 In has been measured. An automatic gamma spectrometer utilizing Ge(Li) and NaI (Tl) detectors was used to measure the angular correlation. The results are analysed in terms of the multipole mixing ratio for the 159 keV transition in 117 Sn. The results are: A 22 = -0 064±0.005, A 44 = 0.005±0.007 with δ(E2/M1) 159keV = 0.036+0.021. The life time of the 159 keV state has also been determined by using the plastic scintillator detectors, and utilizing the delayed gamma-gamma coincidence method the resulting value of the life time is T 1/2 = 275±15 psec. Further measurements have been carried out to determine the nuclear g-factor of the 159 keV state utilizing the NaI(Tl) detectors and an external magnetic field of 25.5 k Gauss. The method of 'integral rotation with reverse field and constant angle' was utilized for the determination of the g-factor with the resulting value of g(159 keV) = +0.47±0.10. The experimental results are discussed in terms of single particle model and the pairing plus quadrupole model of Kisslinger and Sorensen. (author)

Formation of anomalous eutectic in Ni-Sn alloy by laser cladding

Science.gov (United States)

Wang, Zhitai; Lin, Xin; Cao, Yongqing; Liu, Fencheng; Huang, Weidong

2018-02-01

Ni-Sn anomalous eutectic is obtained by single track laser cladding with the scanning velocity from 1 mm/s to 10 mm/s using the Ni-32.5 wt.%Sn eutectic powders. The microstructure of the cladding layer and the grain orientations of anomalous eutectic were investigated. It is found that the microstructure is transformed from primary α-Ni dendrites and the interdendritic (α-Ni + Ni3Sn) eutectic at the bottom of the cladding layer to α-Ni and β-Ni3Sn anomalous eutectic at the top of the cladding layer, whether for single layer or multilayer laser cladding. The EBSD maps and pole figures indicate that the spatially structure of α-Ni phase is discontinuous and the Ni3Sn phase is continuous in anomalous eutectic. The transformation from epitaxial growth columnar at bottom of cladding layer to free nucleation equiaxed at the top occurs, i.e., the columnar to equiaxed transition (CET) at the top of cladding layer during laser cladding processing leads to the generation of anomalous eutectic.

A reduced-amide inhibitor of Pin1 binds in a conformation resembling a twisted-amide transition state.

Science.gov (United States)

Xu, Guoyan G; Zhang, Yan; Mercedes-Camacho, Ana Y; Etzkorn, Felicia A

2011-11-08

The mechanism of the cell cycle regulatory peptidyl prolyl isomerase (PPIase), Pin1, was investigated using reduced-amide inhibitors designed to mimic the twisted-amide transition state. Inhibitors, R-pSer-Ψ[CH(2)N]-Pro-2-(indol-3-yl)ethylamine, 1 [R = fluorenylmethoxycarbonyl (Fmoc)] and 2 (R = Ac), of Pin1 were synthesized and bioassayed. Inhibitor 1 had an IC(50) value of 6.3 μM, which is 4.5-fold better for Pin1 than our comparable ground-state analogue, a cis-amide alkene isostere-containing inhibitor. The change of Fmoc to Ac in 2 improved aqueous solubility for structural determination and resulted in an IC(50) value of 12 μM. The X-ray structure of the complex of 2 bound to Pin1 was determined to 1.76 Å resolution. The structure revealed that the reduced amide adopted a conformation similar to the proposed twisted-amide transition state of Pin1, with a trans-pyrrolidine conformation of the prolyl ring. A similar conformation of substrate would be destabilized relative to the planar amide conformation. Three additional reduced amides, with Thr replacing Ser and l- or d-pipecolate (Pip) replacing Pro, were slightly weaker inhibitors of Pin1.

Optimal trajectories of brain state transitions.

Science.gov (United States)

Gu, Shi; Betzel, Richard F; Mattar, Marcelo G; Cieslak, Matthew; Delio, Philip R; Grafton, Scott T; Pasqualetti, Fabio; Bassett, Danielle S

2017-03-01

The complexity of neural dynamics stems in part from the complexity of the underlying anatomy. Yet how white matter structure constrains how the brain transitions from one cognitive state to another remains unknown. Here we address this question by drawing on recent advances in network control theory to model the underlying mechanisms of brain state transitions as elicited by the collective control of region sets. We find that previously identified attention and executive control systems are poised to affect a broad array of state transitions that cannot easily be classified by traditional engineering-based notions of control. This theoretical versatility comes with a vulnerability to injury. In patients with mild traumatic brain injury, we observe a loss of specificity in putative control processes, suggesting greater susceptibility to neurophysiological noise. These results offer fundamental insights into the mechanisms driving brain state transitions in healthy cognition and their alteration following injury. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Specific heat of Nb3Sn and V2Zr compounds irradiated with high fluences fast neutrons

International Nuclear Information System (INIS)

Kar'kin, A.E.; Mirmel'shtejn, A.V.; Arkhipov, V.E.; Goshchitskij, B.N.

1987-01-01

Specific heat of Nb 3 Sn (structure A15) and V 2 Zr (C15) specimens irradiated with high fluences of bast neutrons has been measured. It is shown that in these compounds the temperature reduction of superconducting transition T c under neutron irradiation is accompanied with high decrease of N(E F ). Phonon spectrum of the irradiated V 2 Zr (amorphous phase) on the whole is harder, than at an initial state, for irradiated Nb 3 Sn state (disordered crystalline structure) phonon spectrum is differ weakly from initial one. General regularities of parameter change of electron and phonon subsystems for A15 compounds investigated here and earlier (V 3 Si, Mo 3 Si, Mo 3 Ge) have been analysed

Effect of thickness on optical properties of thermally evaporated SnS films

International Nuclear Information System (INIS)

Selim, M.S.; Gouda, M.E.; El-Shaarawy, M.G.; Salem, A.M.; Abd El-Ghany, W.A.

2013-01-01

The effect of film thickness on the structure and optical properties of thermally evaporated SnS film has been studied. SnS films with different thicknesses in the range 152–585 nm were deposited onto clean glass substrates at room temperature. X-ray diffraction study revealed that SnS films of thickness ≥ 283 nm are crystalline, whereas films of lower thickness exhibit poor crystalline with more amorphous background. The crystalline nature of the lower film thickness has been confirmed using transmission electron microscope and the corresponding electron diffraction pattern. The thicker film samples showed nearly stoichiometric chemical composition; however, thinner samples are deficient in S and rich in Sn. The optical property of the deposited films has been investigated in the wavelength range 350–2500 nm. The refractive index increases notably with increasing film thickness. The refractive index for the investigated film thicknesses are adequately described by the effective-single-oscillator model. The static refractive index and the static dielectric constant have been calculated. Analysis of the optical absorption coefficient revealed the presence of direct optical transition and the corresponding band gap values were found to decrease as the film thickness increases. - Highlights: ► X-ray diffraction was used to study the structure of SnS films. ► Transmission electron microscope confirms the crystalline state of SnS films. ► The refractive index increases notably with increasing the film thickness. ► The optical band gap of SnS films decreases with increasing film thickness

Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+x Mn50Sn11-x (x ⩽ 2) alloys.

Science.gov (United States)

Prasanna, A A; Ram, Shanker

2013-02-01

Ni 39+ x Mn 50 Sn 11- x ( x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ∼15 mm diameter and 8 mm width. A single martensite phase with a L 1 0 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% ( x = 2), whereas an austenite cubic L 2 1 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips ( x ≽ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite-austenite (or reverse) phase transition. A net residual enthalpy change Δ H M↔A = -0.12 J g -1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (-)26% at 10 T is observed together with a large entropy change of 11.8 mJ g -1 K -1 , nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The Δ H M↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.

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

Pulsed laser deposition of epitaxial Sr(RuxSn1-x)O3 thin film electrodes and KNbO3/Sr(RuxSn1-x)O3 bilayers

International Nuclear Information System (INIS)

Christen, H.M.; Boatner, L.A.; English, L.Q.; Geea, L.A.; Marrero, P.J.; Norton, D.P.

1995-01-01

Sr(Ru x Sn 1-x ) 3 is proposed as a new conducting oxide for use in epitaxial multilayer structures. The Sr(Ru o 48 Sn 0.52 )0 3 composition exhibits an excellent lattice match with (100)-oriented KTaO 3 , and films of this composition grown by pulsed laser deposition on KTaO 3 , SrTiO 3 , and LaAlO 3 substrates have been analyzed by X-ray diffraction, Rutherford backscattering/ion channeling, and resistivity measurements. Epitaxial KNbO 3 /Sr(Ru 0.48 Sn 0.52 )O 3 bilayers have been successfully grown

Determination of a new structure type in the Sc–Fe–Ge–Sn system

International Nuclear Information System (INIS)

Brgoch, Jakoah; Ran, Sheng; Thimmaiah, Srinivasa; Canfield, Paul C.; Miller, Gordon J.

2013-01-01

Highlights: ► A new structure type with the composition Sc 4 Fe 5 Ge 6.10(3) Sn 1.47(2) . ► Crystallizes in the space group Immm (No. 71, oI144). ► Sample obtained using a reactive Sn flux. ► Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc–Fe–Ge–Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc 4 Fe 5 Ge 6.10(3) Sn 1.47(2) and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) Å, b = 13.467(3) Å, and c = 30.003(6) Å. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc–Ge as well as Fe–Sn and Fe–Ge contacts can be assigned to this new structure type.

Optical characteristic and gap states distribution of amorphous SnO2:(Zn, In) film

International Nuclear Information System (INIS)

Zhang Zhi-Guo

2010-01-01

In this paper the fabrication technique of amorphous SnO 2 :(Zn, In) film is presented. The transmittance and gap-states distribution of the film are given. The experimental results of gap-states distribution are compared with the calculated results by using the facts of short range order and lattice vacancy defect of the gap states theory. The distribution of gap state has been proved to be discontinuous due to the short-range order of amorphous structure. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Electric response of Pb0.99[(Zr0.90Sn0.10)0.968Ti0.032]0.98Nb0.02O3 ceramics to the shock-wave-induced ferroelectric-to-antiferroelectric phase transition

International Nuclear Information System (INIS)

Jiang Dongdong; Zhang Na; Feng Yujun; Du Jinmei; Gu Yan

2012-01-01

Highlights: ► Shock wave induces the FE-to-AFE phase transition in PbNb(Zr,Sn,Ti)O 3 . ► Depoling current due to phase transition depends on shock pressure and load resistance. ► Shock pressure promotes the phase transition in short-circuit case. ► Increasing load resistance decreases the released charge. - Abstract: Shock-wave-enforced ferroelectric (FE)-to-antiferroelectric (AFE) phase transition releases a large electrical polarization, having application in pulse power technology. In the present work, the depoling currents under shock wave compression were investigated in Pb 0.99 [(Zr 0.90 Sn 0.10 ) 0.968 Ti 0.032 ] 0.98 Nb 0.02 O 3 (PZST) ceramics with composition close to the FE/AFE phase boundary. Shock wave was generated by gas-gun and propagated in a direction perpendicular to the remanent polarization. It was found that the shock pressure promoted the phase transition under the short-circuit condition. The shock pressure dependence of the released charge was associated with the evolution of FE-to-AFE phase transition. The onset of phase transition was about 0.40 GPa and complete transformation occurred at 1.23 GPa. However, the released charge decreased with increasing load resistance. The reason may be that the electric field suppresses the phase transition in uncompressed zone and/or shock induces conductivity in compressed zone. Results lay the foundation for application of PZST ceramics in shock-activated power supply.

Conversion of 1-alkyl-2-acetyl-sn-glycerols to platelet activating factor and related phospholipids by rabbit platelets

International Nuclear Information System (INIS)

Blank, M.L.; Lee, T.; Cress, E.A.; Malone, B.; Fitzgerald, V.; Snyder, F.

1984-01-01

The metabolic pathway for 1-alkyl-2-acetyl-sn-glycerols, a recently discovered biologically active neutral lipid class, was elucidated in experiments conducted with rabbit platelets. The total lipid extract obtained from platelets incubated with 1-[1-,2- 3 H]alkyl-2-acetyl-sn-glycerols or 1-alkyl-2-[ 3 H]acetyl-sn-glycerols contained at least six metabolic products. The six metabolites, identified on the basis of chemical and enzymatic reactions combined with thin-layer or high-performance liquid chromatographic analyses, corresponded to 1-alkyl-sn-glycerols, 1-alkyl-2-acetyl-sn-glycero-3-phosphates, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphocholines, and 1-alkyl-2-actyl-sn-glycero-3-phosphocholines (platelet activating factor). These results indicate that the metabolic pathway for alkylacetylglycerols involves reaction steps catalyzed by the following enzymatic activities: choline- and ethanolamine- phosphotransferases, acetyl-hydrolase, an acyltransferase, and a phosphotransferase. The step responsible for the biosynthesis of platelet activating factor would appear to be the most important reaction in this pathway and this product could explain the hypotensive activities previously described for alkylacetyl-(or propionyl)-glycerols. Of particular interest was the preference exhibited for the utilization of the 1-hexadecyl-2-acetyl-sn-glycerol species in the formation of platelet activating factor

Ethanol electrooxidation on novel carbon supported Pt/SnO{sub x}/C catalysts with varied Pt:Sn ratio

Energy Technology Data Exchange (ETDEWEB)

Jiang, L. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian (China); Colmenares, L.; Jusys, Z. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Sun, G.Q. [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian (China)], E-mail: gqsun@dicp.ac.cn; Behm, R.J. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany)], E-mail: juergen.behm@uni-ulm.de

2007-12-01

Novel carbon supported Pt/SnO{sub 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{sub ad} stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO{sub 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{sub x}/C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO{sub x}/C catalysts, acetic acid and acetaldehyde represent dominant products, CO{sub 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{sup -1}), but are lower than on Pt/C (32 kJ mol{sup -1}). The somewhat better performance of the Pt/SnO{sub x}/C catalysts compared to alloyed PtSn{sub 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.

In vitro and in vivo evaluation of SN-38 nanocrystals with different particle sizes

Directory of Open Access Journals (Sweden)

Chen M

2017-08-01

Full Text Available Min Chen,1,2 Wanqing Li,3 Xun Zhang,1 Ye Dong,1 Yabing Hua,1 Hui Zhang,1 Jing Gao,1 Liang Zhao,2 Ying Li,1 Aiping Zheng1 1State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 2School of Pharmacy, Jinzhou Medical University, Jinzhou, 3School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, People’s Republic of China Abstract: 7-Ethyl-10-hydroxycamptothecin (SN-38 is a potent broad-spectrum antitumor drug derived from irinotecan hydrochloride (CPT-11. Due to its poor solubility and instability of the active lactone ring, its clinical use is significantly limited. As one of the most promising formulations for poorly water-soluble drugs, nanocrystals have attracted increasing attention. In order to solve these problems and evaluate the antitumor effect of SN-38 in vitro and in vivo, two nanocrystals with markedly different particle sizes were prepared. Dynamic light scattering and transmission electron microscopy were used to investigate the two nanocrystals. The particle sizes of SN-38 nanocrystals A (SN-38/NCs-A and SN-38 nanocrystals B (SN-38/NCs-B were 229.5±1.99 and 799.2±14.44 nm, respectively. X-ray powder diffraction analysis showed that the crystalline state of SN-38 did not change in the size reduction process. An accelerated dissolution velocity of SN-38 was achieved by nanocrystals, and release rate of SN-38/NCs-A was significantly faster than that of SN-38/NCs-B. Cellular uptake, cellular cytotoxicity, pharmacokinetics, animal antitumor efficacy, and tissue distribution were subsequently examined. As a result, enhanced intracellular accumulation in HT1080 cells and cytotoxicity on different tumor cells were observed for SN-38/NCs-A compared to that for SN-38/NCs-B and solution. Besides, compared to the SN-38 solution, SN-38/NCs-A had a higher bioavailability after intravenous injection; while the bioavailability of SN-38/NCs-B was even lower than

GLAG theory for superconducting property variations with A15 composition in Nb3Sn wires.

Science.gov (United States)

Li, Yingxu; Gao, Yuanwen

2017-04-25

We present a model for the variation of the upper critical field H c2 with Sn content in A15-type Nb-Sn wires, within the Ginzburg-Landau-Abrikosov-Gor'kov (GLAG) theory frame. H c2 at the vicinity of the critical temperature T c is related quantitatively to the electrical resistivity ρ, specific heat capacity coefficient γ and T c . H c2 versus tin content is theoretically formulated within the GLAG theory, and generally reproduces the experiment results. As Sn content gradually approaches the stoichiometry, A15-type Nb-Sn undergoes a transition from the dirty limit to clean limit, split by the phase transformation boundary. The H-T phase boundary and pinning force show different behaviors in the cubic and tetragonal phase. We dipict the dependence of the composition gradient on the superconducting properties variation in the A15 layer, as well as the curved tail at vicinity of H c2 in the Kramer plot of the Nb 3 Sn wire. This helps understanding of the inhomogeneous-composition inducing discrepancy between the results by the state-of-art scaling laws and experiments.

Quantum phase transitions in matrix product states of one-dimensional spin-1 chains

International Nuclear Information System (INIS)

Zhu Jingmin

2014-01-01

We present a new model of quantum phase transitions in matrix product systems of one-dimensional spin-1 chains and study the phases coexistence phenomenon. We find that in the thermodynamic limit the proposed system has three different quantum phases and by adjusting the control parameters we are able to realize any phase, any two phases equal coexistence and the three phases equal coexistence. At every critical point the physical quantities including the entanglement are not discontinuous and the matrix product system has long-range correlation and N-spin maximal entanglement. We believe that our work is helpful for having a comprehensive understanding of quantum phase transitions in matrix product states of one-dimensional spin chains and of certain directive significance to the preparation and control of one-dimensional spin lattice models with stable coherence and N-spin maximal entanglement. (author)

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.

Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave dielectric ceramic

Science.gov (United States)

Hu, Mingzhe; Wei, Huanghe; Xiao, Lihua; Zhang, Kesheng; Hao, Yongde

2017-10-01

The crystal structure and dielectric properties of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the B-site order-disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramic can be compensated and the optimal microwave dielectric properties can reach 𝜀r = 25.66, Qf = 18,894 GHz and TCF = -6.3 ppm/∘C when sintered at 1170∘C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.

Neutron emission spectra and level density of hot rotating 132Sn

International Nuclear Information System (INIS)

Aggarwal, Mamta

2008-01-01

The neutron emission spectrum of the highly excited compound nuclear system 132 Sn is investigated at high spin. The doubly magic nucleus 132 Sn undergoes a shape transition at high angular momentum which affects the nuclear level density and neutron emission probability considerably. The interplay of temperature, shape, deformation and rotational degrees of freedom and their influence on neutron emission is emphasized. We predict an enhancement of nucleonic emission at those spins where the nucleus suffers a transition from a spherical to deformed shape. (author)

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

Energy Technology Data Exchange (ETDEWEB)

Huang, Y.J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shen, J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: junshen@hit.edu.cn; Sun, J.F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yu, X.B. [Lab of Energy Science and Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)]. E-mail: yuxuebin@hotmail.com

2007-01-16

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 42.5-x}Ni{sub 7.5}Si{sub 1}Sn {sub x} (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy. The activation energies for glass transition and crystallization for Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy also possesses superior mechanical properties.

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)

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%.

Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2 = 1 states of ammonia.

Science.gov (United States)

Yu, Shanshan; Pearson, John C; Drouin, Brian J; Sung, Keeyoon; Pirali, Olivier; Vervloet, Michel; Martin-Drumel, Marie-Aline; Endres, Christian P; Shiraishi, Tetsuro; Kobayashi, Kaori; Matsushima, Fusakazu

2010-11-07

Complete and reliable knowledge of the ammonia spectrum is needed to enable the analysis and interpretation of astrophysical and planetary observations. Ammonia has been observed in the interstellar medium up to J=18 and more highly excited transitions are expected to appear in hot exoplanets and brown dwarfs. As a result, there is considerable interest in observing and assigning the high J (rovibrational) spectrum. In this work, numerous spectroscopic techniques were employed to study its high J transitions in the ground and ν(2)=1 states. Measurements were carried out using a frequency multiplied submillimeter spectrometer at Jet Propulsion Laboratory (JPL), a tunable far-infrared spectrometer at University of Toyama, and a high-resolution Bruker IFS 125 Fourier transform spectrometer (FTS) at Synchrotron SOLEIL. Highly excited ammonia was created with a radiofrequency discharge and a dc discharge, which allowed assignments of transitions with J up to 35. One hundred and seventy seven ground state and ν(2)=1 inversion transitions were observed with microwave accuracy in the 0.3-4.7 THz region. Of these, 125 were observed for the first time, including 26 ΔK=3 transitions. Over 2000 far-infrared transitions were assigned to the ground state and ν(2)=1 inversion bands as well as the ν(2) fundamental band. Of these, 1912 were assigned using the FTS data for the first time, including 222 ΔK=3 transitions. The accuracy of these measurements has been estimated to be 0.0003-0.0006 cm(-1). A reduced root mean square error of 0.9 was obtained for a global fit of the ground and ν(2)=1 states, which includes the lines assigned in this work and all previously available microwave, terahertz, far-infrared, and mid-infrared data. The new measurements and predictions reported here will support the analyses of astronomical observations by high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA. The comprehensive experimental rovibrational energy levels

Heat-capacity measurement on (Zr1-ySny)Ox from 325 to 905 K

International Nuclear Information System (INIS)

Tsuji, Toshihide; Amaya, Masaki; Naito, Keiji

1993-01-01

Heat capacities of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 (y=0-0.07) having α''-ZrO ∼1/6 and α''-ZrO x type crystal structures, respectively, were measured from 325 to 905 K by using an adiabatic scanning calorimeter. Two kinds of heat capacity anomalies were observed for all samples. The anomaly at lower temperatures is attributed to a nonequilibrium phenomenon. Another anomaly at higher temperatures is assigned to an order-disorder rearrangement of oxygen atoms. The transition temperature, transition enthalpy and entropy changes due to the order-disorder transition decreased with increasing tin content, indicating that arrangement of oxygen atoms in the lower temperature phase may be partially disordered by substituting tin for zirconium. The entropy change due to the order-disorder transition for (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 solid solutions is compared with the theoretical value. The solubility limits of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 were determined from the variation of lattice constants, transition temperature, transition enthalpy and entropy changes against tin content. (orig.)

Study of 4f hybridization in CeNiX with X=Sn{sub d}eltaGe{sub 1-d}elta, 0<=delta<=1

Energy Technology Data Exchange (ETDEWEB)

Fuente, C. de la, E-mail: cesar@unizar.e [Depto. Fisica de la Materia Condensada, Laboratorio de Magnetismo, Universidad de Zaragoza and ICMA-CSIC (Spain); Moral, A. del [Depto. Fisica de la Materia Condensada, Laboratorio de Magnetismo, Universidad de Zaragoza and ICMA-CSIC (Spain); Adroja, D.T. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Fraile, A. [Depto. Fisica de la Materia Condensada, Laboratorio de Magnetismo, Universidad de Zaragoza and ICMA-CSIC (Spain); Arnaudas, J.I. [Instituto de Nanociencia de Aragon, Universidad de Zaragoza (Spain)

2010-05-15

We report inelastic neutron scattering and core-level X-ray photoemission spectroscopy experiments for studying the Kondo problem in the CeNiX, X=Sn{sub d}eltaGe{sub 1-d}elta 0<=delta<=1 series. The neutron results confirm that they behave like a Kondo lattice for delta>=0.85, showing broad maxima at around 30 meV, typical of a crystal field magnetic scattering. So, the Ge doping could produce the suppression of the cerium magnetism observed for delta<=0.25. To open a more deep sight on this point, we have analyzed the 3d core-level XPS spectra by using the well-known Gunnarsson-Schoenhammer model. From this analysis, we have obtained the 'on-site' Coulomb bare repulsion for f states, U, and hybridization parameter, DELTA, related with the hopping from the f states to the conduction ones. These U values are very similar for all compounds, about 7 eV, but the hybridization parameter slightly changes from 0.2 to 0.16 eV on increasing the Sn concentration. In Sn-rich compounds, the 4f occupation is close to spin limit fluctuation, which allows us to obtain an estimation of the Kondo temperatures, approx1200 K, and the static 0 K susceptibility, approx1.1x10{sup -3} emu/mol. Finally, we have done 'ab-initio' calculations based on the LDA+U+SO which confirm the existence of a small electronic gap opening in the DOS of Ge-rich compounds for U values lower than 7 eV.

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.

Solid state chemistry of new polysulphides in A/Sn/S (A = Na, K, Rb ...

Indian Academy of Sciences (India)

Administrator

Solid state chemistry of new polysulphides in A/Sn/S (A = Na, K,. Rb) systems. M SUSEELA DEVI and K VIDYASAGAR. Department of Chemistry, Indian Institute of Technology Madras,. Chennai 600 036, India. Ternary polychalcogenides containing chalocogen–chalcogen bonds are metastable compounds that have been ...

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

Role of oxygen defects on the magnetic properties of ultra-small Sn1-xFexO2 nanoparticles

Science.gov (United States)

Dodge, Kelsey; Chess, Jordan; Eixenberger, Josh; Alanko, Gordon; Hanna, Charles B.; Punnoose, Alex

2013-05-01

Although the role of oxygen defects in the magnetism of metal oxide semiconductors has been widely discussed, it is been difficult to directly measure the oxygen defect concentration of samples to verify this. This work demonstrates a direct correlation between the photocatalytic activity of Sn1-xFexO2 nanoparticles and their magnetic properties. For this, a series of ˜2.6 nm sized, well characterized, single-phase Sn1-xFexO2 crystallites with x = 0-0.20 were synthesized using tin acetate, urea, and appropriate amounts of iron acetate. X-ray photoelectron spectroscopy confirmed the concentration and 3+ oxidation state of the doped Fe ions. The maximum magnetic moment/Fe ion, μ, of 1.6 × 10-4 μB observed for the 0.1% Fe doped sample is smaller than the expected spin-only contribution from either high or low spin Fe3+ ions, and μ decreases with increasing Fe concentration. This behavior cannot be explained by the existing models of magnetic exchange. Photocatalytic studies of pure and Fe-doped SnO2 were used to understand the roles of doped Fe3+ ions and of the oxygen vacancies and defects. The photocatalytic rate constant k also showed an increase when SnO2 nanoparticles were doped with low concentrations of Fe3+, reaching a maximum at 0.1% Fe, followed by a rapid decrease of k for further increase in Fe%. Fe doping presumably increases the concentration of oxygen vacancies, and both Fe3+ ions and oxygen vacancies act as electron acceptors to reduce e--h+ recombination and promote transfer of electrons (and/or holes) to the nanoparticle surface, where they participate in redox reactions. This electron transfer from the Fe3+ ions to local defect density of states at the nanoparticle surface could develop a magnetic moment at the surface states and leads to spontaneous ferromagnetic ordering of the surface shell under favorable conditions. However, at higher doping levels, the same Fe3+ ions might act as recombination centers causing a decrease of both k and

Study of tin amalgam mirrors by "1"1"9Sn Mössbauer spectroscopy and other analytical methods

International Nuclear Information System (INIS)

Lerf, A.; Wagner, F. E.; Herrera, L. K.; Justo, A.; Mu noz-Páez, A.; Pérez-Rodríguez, J. L.

2016-01-01

From the beginning of the 16 "t"h until the end of the 19 "t"h century the most widely used mirrors consisted of a pane of glass backed with a reflecting layer of tin-mercury amalgam. They were made by sliding the glass pane over a tin foil covered with liquid mercury. After removal of the superfluous mercury, tin amalgam formed slowly at ambient temperature and yielded a reflecting layer adhering to the surface of the glass. Such mirrors often deteriorate in the course of time by oxidation of the tin in the amalgam to stannous or stannic oxide. "1"1"9Sn Mössbauer spectroscopy, scanning electron microscopy, micro-XRF and X-ray diffraction have been used to study this deterioration process. The studied specimens were a modern mirror made for the reconstruction of the Green Vault in Dresden in the early 2000s, two rather well preserved German mirrors from the 17 "t"h and 19 "t"h centuries and several strongly deteriorated specimens of Baroque mirrors from the south of Spain. The modern mirror consists mainly of a Sn_0_._9Hg_0_._1 amalgam with only 2 % of SnO_2. The older German mirrors showed more pronounced oxidation, containing 12 and 15 % of SnO_2, which did not noticeably impair their reflectivity. In the samples from the Spanish mirrors at best a few percent of metallic phase was left. The majority of the tin had oxidised to SnO_2, but between 8 and 20 % of the tin was present as SnO. X-ray diffraction yielded similar results and micro-XRF mapping using synchrotron radiation for excitation gave information on the distribution of Sn and Hg in the reflecting layer of the mirrors.

Platinum(0-1,3-divinyl-1,1,3,3-tetramethyldisiloxane Complex as a Pt Source for Pt/SnO2 Catalyst

Directory of Open Access Journals (Sweden)

Agnieszka Martyla

2014-01-01

Full Text Available This paper presents new preparation method of Pt/SnO2, an important catalytic system. Besides of its application as a heterogenic industrial catalyst, it is also used as a catalyst in electrochemical processes, especially in fuel cells. Platinum is commonly used as an anode catalyst in low temperature fuel cells, fuelled with alcohols of low molecular weight such as methanol. Platinum(0-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex was used as a precursor of metallic phase. The aim of the research was to obtain a highly active in electrochemical system Pt/SnO2 catalyst with low metal load. Considering small size of Pt crystallites, it should result in high activity of Pt/SnO2 system. The presented method of SnO2 synthesis allows for obtaining support consisting of nanoparticles. The effect of the thermal treatment on activity of Pt/SnO2 gel was demonstrated. The system properties were investigated using TEM, FTIR (ATR, and XRD techniques to describe its thermal structural evolution. The results showed two electrocatalytical activity peaks for drying at a temperature of 430 K and above 650 K.

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

Spectroscopic ellipsometry characterization of ZnO:Sn thin films with various Sn composition deposited by remote-plasma reactive sputtering

Science.gov (United States)

Janicek, Petr; Niang, Kham M.; Mistrik, Jan; Palka, Karel; Flewitt, Andrew J.

2017-11-01

ZnO:Sn thin films were deposited onto thermally oxidized silicon substrates using a remote plasma reactive sputtering. Their optical constants (refractive index n and extinction coefficient k) were determined from ellipsometric data recorded over a wide spectral range (0.05-6 eV). Parametrization of ZnO:Sn complex dielectric permittivity consists of a parameterized semiconductor oscillator function describing the short wavelength absorption edge, a Drude oscillator describing free carrier absorption in near-infrared part of spectra and a Lorentz oscillator describing the long wavelength absorption edge and intra-band absorption in the ultra-violet part of the spectra. Using a Mott-Davis model, the increase in local disorder with increasing Sn doping is quantified from the short wavelength absorption edge onset. Using the Wemple-DiDomenico single oscillator model for the transparent part of the optical constants spectra, an increase in the centroid distance of the valence and conduction bands with increasing Sn doping is shown and only slight increase in intensity of the inter-band optical transition due to Sn doping occurs. The Drude model applied in the near-infrared part of the spectra revealed the free carrier concentration and mobility of ZnO:Sn. Results show that the range of transparency of prepared ZnO:Sn layers is not dramatically affected by Sn doping whereas electrical conductivity could be controlled by Sn doping. Refractive index in the transparent part is comparable with amorphous Indium Gallium Zinc Oxide allowing utilization of prepared ZnO:Sn layers as an indium-free alternative.

High-resolution photoluminescence spectroscopy of Sn-doped ZnO single crystals

International Nuclear Information System (INIS)

Kumar, E. Senthil; Mohammadbeigi, F.; Boatner, L.A.; Watkins, S.P.

2016-01-01

Group IV donors in ZnO are poorly understood, despite evidence that they are effective n-type dopants. Here we present high-resolution photoluminescence (PL) spectroscopy studies of unintentionally doped and Sn-doped ZnO single crystals grown by the chemical vapor transport method. Doped samples showed greatly increased emission from the I 10 bound exciton transition that was recently proven to be related to the incorporation of Sn impurities based on radio-isotope studies. The PL linewidths are exceptionally sharp for these samples, enabling a clear identification of several donor species. Temperature-dependent PL measurements of the I 10 line emission energy and intensity dependence reveal a behavior that is similar to other shallow donors in ZnO. Ionized donor bound-exciton and two-electron satellite transitions of the I 10 transition are unambiguously identified and yield a donor binding energy of 71 meV. In contrast to recent reports of Ge-related donors in ZnO, the spectroscopic binding energy for the Sn-related donor bound exciton follows a linear relationship with donor binding energy (Haynes rule) similar to recently observed carbon related donors, and confirming the shallow nature of this defect center, which was recently attributed to a Sn Zn double donor compensated by an unknown single acceptor.

Highly sensitive electrochemical determination of 1-naphthol based on high-index facet SnO2 modified electrode

International Nuclear Information System (INIS)

Huang Xiaofeng; Zhao Guohua; Liu Meichuan; Li Fengting; Qiao Junlian; Zhao Sichen

2012-01-01

Highlights: ► It is the first time to employ high-index faceted SnO 2 in electrochemical analysis. ► High-index faceted SnO 2 has excellent electrochemical activity toward 1-naphthol. ► Highly sensitive determination of 1-naphthol is realized on high-index faceted SnO 2 . ► The detection limit of 1-naphthol is as low as 5 nM on high-index faceted SnO 2 . ► Electro-oxidation kinetics for 1-napthol on the novel electrode is discussed. - Abstract: SnO 2 nanooctahedron with {2 2 1} high-index facet (HIF) was synthesized by a simple hydrothermal method, and was firstly employed to sensitive electrochemical sensing of a typical organic pollutant, 1-naphthol (1-NAP). The constructed HIF SnO 2 modified glassy carbon electrode (HIF SnO 2 /GCE) possessed advantages of large effective electrode area, high electron transfer rate, and low charge transfer resistance. These improved electrochemical properties allowed the high electrocatalytic performance, high effective active sites and high adsorption capacity of 1-NAP on HIF SnO 2 /GCE. Cyclic voltammetry (CV) results showed that the electrochemical oxidation of 1-NAP obeyed a two-electron transfer process and the electrode reaction was under diffusion control on HIF SnO 2 /GCE. By adopting differential pulse voltammetry (DPV), electrochemical detection of 1-NAP was conducted on HIF SnO 2 /GCE with a limit of detection as low as 5 nM, which was relatively low compared to the literatures. The electrode also illustrated good stability in comparison with those reported value. Satisfactory results were obtained with average recoveries in the range of 99.7–103.6% in the real water sample detection. A promising device for the electrochemical detection of 1-NAP with high sensitivity has therefore been provided.

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.

Spectral intensities in coordination compounds of the transition metals: applications to systems type Cs2SnBr6: OsBr6

International Nuclear Information System (INIS)

Acevedo, R.; Munoz, G.; Meruane, T.

2001-01-01

The luminescence spectrum of the Cs 2 SnBr 6 : OsBr 6 system is examined utilizing a generalized vibronic formalisms. For illustrative purposes we have chosen the most characteristic excitations, which show up a rich and unexpected vibronic structures. These absorptions are tackled with emphasis on both the electronic and the vibrational factors which are responsible for both the overall and the relative vibronic intensities associated with generic transitions of the Γ m = Γ l + v k (k = 3, 4, 6) type. The advantages and disadvantages of the calculation models as well as a critical studies of the experimental data available are discussed. Relevant conclusions are drawn out in connection with the intensity spectral mechanism as well as the eventual influence on the calculated intensities due to the coupling among the internal and the external vibrations and some suggestions for improvement are put forward to advance the state of the art in the vibronic coupling theory. (Author)

Effects of the thermal and magnetic paths on first order martensite transition of disordered Ni45Mn44Sn9In2 Heusler alloy exhibiting a giant magnetocaloric effect and magnetoresistance near room temperature

Science.gov (United States)

Chabri, T.; Ghosh, A.; Nair, Sunil; Awasthi, A. M.; Venimadhav, A.; Nath, T. K.

2018-05-01

The existence of a first order martensite transition in off-stoichiometric Ni45Mn44Sn9In2 ferromagnetic shape memory Heusler alloy has been clearly observed by thermal, magnetic, and magneto-transport measurements. Field and thermal path dependence of the change in large magnetic entropy and negative magnetoresistance are observed, which originate due to the sharp change in magnetization driven by metamagnetic transition from the weakly magnetic martensite phase to the ferromagnetic austenite phase in the vicinity of the martensite transition. The noticeable shift in the martensite transition with the application of a magnetic field is the most significant feature of the present study. This shift is due to the interplay of the austenite and martensite phase fraction in the alloy. The different aspects of the first order martensite transition, e.g. broadening of the martensite transition and the field induced arrest of the austenite phase are mainly related to the dynamics of coexisting phases in the vicinity of the martensite transition. The alloy also shows a second order ferromagnetic  →  paramagnetic transition near the Curie temperature of the austenite phase. A noticeably large change in magnetic entropy (ΔS M   =  24 J kg‑1 K‑1 at 298 K) and magnetoresistance (=  ‑33% at 295 K) has been observed for the change in 5 and 8 T magnetic fields, respectively. The change in adiabatic temperature for the change in a magnetic field of 5 T is found to be  ‑3.8 K at 299 K. The low cost of the ingredients and the large change in magnetic entropy very near to the room temperature makes Ni45Mn44Sn9In2 alloy a promising magnetic refrigerant for real technological application.

Hyperfine magnetic fields at 57Fe and 119Sn nuclei in the Fe48Rh52 alloy under pressure

International Nuclear Information System (INIS)

Nikolaev, I.N.; Potapov, V.N.; Bezotosnyj, I.Yu.; Mar'in, V.P.

1978-01-01

The pressure dependences of the hyperfine magnetic fields, H, and isomer shifts epsilon at the 57 Fe and 119 Sn nuclei in the Fe 48 Rh 52 alloy with an admixture of approximately 1 at. % Sn are measured by the Moessbauer effect technique. Under pressure epsilon decreases this signifying an increase (for 57 Fe) or decrease (for 119 Sn) of the s-electron density at the nuclei. In the ferromagnetic (FM) state at 398 K, ΔH/HΔp=(-2.8+-0.2)x10 -3 kbar -1 for 57 Fe and ΔH/HΔp=(-4.8+-0.8)x10 -3 kbar -1 for 119 Sn. In the antiferromagnetic (AFM) state at 78 K, ΔH/HΔp approximately 0 for 57 Fe and ΔH/HΔp=(-6.2+-1.0)x10 -3 kbar -1 for 119 Sn. The results for 57 Fe in the FM state can be ascribed to the strong dependence of the alloy matrix magnetization on the pressure and in the AFM state to the absence of local polarization of s-similar collectivized electrons and to the independence of the magnetic moments of the Fe ions of pressure. The causes of the different effect of pressure on the magnetic moments of Fe ions in the FM and AFM states are discussed. The results for 119 Sn in the FM and AFM states of the alloy are in agreement with the model of hyperfine fields at impurity Sn atoms in the magnetic matrices proposed earlier. The radial dependence of the hyperfine field at the 119 Sn nuclei in the AFM state is estimated and it is found that H(r) is stronger than r -9

Study on introduction of SN transition type FCL into distribution systems

International Nuclear Information System (INIS)

Kameda, Hideyuki; Uemura, Satoshi; Ichinose, Ataru

2013-01-01

Highlights: •We describe the arrangement of SNFCL into a present and a future distribution system. •The FCLs near loop-switches can prevent a blackout against a fault within the loop. •The FCLs enable us to enhance the flexibility of the system configuration. -- Abstract: The suitable introduction method of SN transition type superconducting fault current limiter (SNFCL) into a typical 6.6-kVdistribution system in Japan is described. A present distribution system is operated in the radial configuration and aged equipment with the isolated neutral system. An introduction of the FCLs into this system could expect to become a countermeasure against a short-circuit when introducing distributed generations in a future looped distribution system, the entire system will go into a blackout without any countermeasures, when a fault occurs within the looped system. But the introduction of the FCLs is expected to localize a blackout and to enhance the flexibility of a system configuration. In order to achieve the above-mentioned purposes of the introduction of the FCLs, the setting method of the parameters which a user should set is proposed using the transient analysis model of the SNFCL which we have ever developed

SN 2015as: a low-luminosity Type IIb supernova without an early light-curve peak

Science.gov (United States)

Gangopadhyay, Anjasha; Misra, Kuntal; Pastorello, A.; Sahu, D. K.; Tomasella, L.; Tartaglia, L.; Singh, Mridweeka; Dastidar, Raya; Srivastav, S.; Ochner, P.; Brown, Peter J.; Anupama, G. C.; Benetti, S.; Cappellaro, E.; Kumar, Brajesh; Kumar, Brijesh; Pandey, S. B.

2018-05-01

We present results of the photometric (from 3 to 509 d post-explosion) and spectroscopic (up to 230 d post-explosion) monitoring campaign of the He-rich Type IIb supernova (SN) 2015as. The (B - V) colour evolution of SN 2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs to the SN IIb subgroup that does not show the early, short-duration photometric peak. The light curve of SN 2015as reaches the B-band maximum about 22 d after the explosion, at an absolute magnitude of -16.82 ± 0.18 mag. At ˜75 d after the explosion, its spectrum transitions from that of a SN II to a SN Ib. P Cygni features due to He I lines appear at around 30 d after explosion, indicating that the progenitor of SN 2015as was partially stripped. For SN 2015as, we estimate a 56Ni mass of ˜0.08 M⊙ and ejecta mass of 1.1-2.2 M⊙, which are similar to the values inferred for SN 2008ax. The quasi-bolometric analytical light-curve modelling suggests that the progenitor of SN 2015as has a modest mass (˜0.1 M⊙), a nearly compact (˜0.05 × 1013 cm) H envelope on top of a dense, compact (˜2 × 1011 cm) and a more massive (˜1.2 M⊙) He core. The analysis of the nebular phase spectra indicates that ˜0.44 M⊙ of O is ejected in the explosion. The intensity ratio of the [Ca II]/[O I] nebular lines favours either a main-sequence progenitor mass of ˜15 M⊙ or a Wolf-Rayet star of 20 M⊙.

M1 and E2 transitions in the ground-state configuration of atomic ...

Indian Academy of Sciences (India)

have calculated the forbidden transition (M1 and E2) parameters such as transition energies, log- arithmic weighted ... Keywords. Forbidden transitions; transition energies; logarithmic weighted oscillator strengths; .... optimizing the energy function based on the non-relativistic Hamiltonian of an atom,. HNR = N. ∑ j=1. (12∇ ...

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

Electrochemical corrosion of Pb-1 wt% Sn and Pb-2.5 wt% Sn alloys for lead-acid battery applications

Energy Technology Data Exchange (ETDEWEB)

Osorio, Wislei R.; Peixoto, Leandro C.; Garcia, Amauri [Department of Materials Engineering, State University of Campinas - UNICAMP, PO Box 612, 13083-970 Campinas, SP (Brazil)

2009-12-01

The aim of this study was to compare the electrochemical corrosion behavior of as-cast Pb-1 wt% Sn and Pb-2.5 wt% Sn alloy samples in a 0.5 M H{sub 2}SO{sub 4} solution at 25 C. A water-cooled unidirectional solidification system was used to obtain the as-cast samples. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the electrochemical corrosion response. It was found that a coarse cellular array has a better electrochemical corrosion resistance than fine cells. The pre-programming of microstructure cell size of Pb-Sn alloys can be used as an alternative way to produce as-cast components of lead-acid batteries with higher corrosion resistance associated with environmental and economical aspects. (author)

A Model of Mental State Transition Network

Science.gov (United States)

Xiang, Hua; Jiang, Peilin; Xiao, Shuang; Ren, Fuji; Kuroiwa, Shingo

Emotion is one of the most essential and basic attributes of human intelligence. Current AI (Artificial Intelligence) research is concentrating on physical components of emotion, rarely is it carried out from the view of psychology directly(1). Study on the model of artificial psychology is the first step in the development of human-computer interaction. As affective computing remains unpredictable, creating a reasonable mental model becomes the primary task for building a hybrid system. A pragmatic mental model is also the fundament of some key topics such as recognition and synthesis of emotions. In this paper a Mental State Transition Network Model(2) is proposed to detect human emotions. By a series of psychological experiments, we present a new way to predict coming human's emotions depending on the various current emotional states under various stimuli. Besides, people in different genders and characters are taken into consideration in our investigation. According to the psychological experiments data derived from 200 questionnaires, a Mental State Transition Network Model for describing the transitions in distribution among the emotions and relationships between internal mental situations and external are concluded. Further more the coefficients of the mental transition network model were achieved. Comparing seven relative evaluating experiments, an average precision rate of 0.843 is achieved using a set of samples for the proposed model.

The order-disorder transition in Cu2ZnSnS4: A theoretical and experimental study

International Nuclear Information System (INIS)

Quennet, Marcel; Ritscher, Anna; Lerch, Martin; Paulus, Beate

2017-01-01

In this work the Cu/Zn order-disorder transition in Cu 2 ZnSnS 4 kesterites on Wyckoff positions 2c and 2d was investigated by a structural and electronic analysis in theory and experiment. For experimental investigations stoichiometric samples with different Cu/Zn order, annealed in the temperature range of 473–623 K and afterwards quenched, were used. The optical gaps were determined using the Derivation of Absorption Spectrum Fitting (DASF) method. Furthermore, the order-disorder transition was examined by DFT calculations for a closer analysis of the origins of the reduced band gap, showing a good agreement with experimental data with respect to structural and electronic properties. Our studies show a slight increase of lattice parameter c in the kesterite lattice with increasing disorder. Additionally, a reduced band gap was observed with increasing disorder, which is an effect of newly occurring binding motifs in the disordered kesterite structure. - Highlights: • Experimental and theoretical investigation on the order-disorder transition in kesterites. • Slight enlargements of lattice constants due to disorder in experiment and theory. • Strong band gap fluctuations with decreasing order. • Electronic structure deviations due to changing binding motifs. • Disorder as possible main source of low open-circuit voltages.

Rapid Communication: v= 2 seniority changing transitions in yrast 3 ...

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics; Volume 89; Issue 5. Rapid Communication: Δ υ = 2 seniority changing transitions in yrast 3 − states and B ( E 3 ) systematics of Sn isotopes. BHOOMIKA MAHESHWARI SWATI GARG ASHOK KUMAR JAIN. Research Article Volume 89 Issue 5 November 2017 Article ID 75 ...

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

Quantum phase transitions between a class of symmetry protected topological states

Energy Technology Data Exchange (ETDEWEB)

Tsui, Lokman; Jiang, Hong-Chen; Lu, Yuan-Ming; Lee, Dung-Hai

2015-07-01

The subject of this paper is the phase transition between symmetry protected topological states (SPTs). We consider spatial dimension d and symmetry group G so that the cohomology group, Hd+1(G,U(1)), contains at least one Z2n or Z factor. We show that the phase transition between the trivial SPT and the root states that generate the Z2n or Z groups can be induced on the boundary of a (d+1)-dimensional View the MathML source-symmetric SPT by a View the MathML source symmetry breaking field. Moreover we show these boundary phase transitions can be “transplanted” to d dimensions and realized in lattice models as a function of a tuning parameter. The price one pays is for the critical value of the tuning parameter there is an extra non-local (duality-like) symmetry. In the case where the phase transition is continuous, our theory predicts the presence of unusual (sometimes fractionalized) excitations corresponding to delocalized boundary excitations of the non-trivial SPT on one side of the transition. This theory also predicts other phase transition scenarios including first order transition and transition via an intermediate symmetry breaking phase.

Constraints on reconstructed dark energy model from SN Ia and BAO/CMB observations

Energy Technology Data Exchange (ETDEWEB)

Mamon, Abdulla Al [Manipal University, Manipal Centre for Natural Sciences, Manipal (India); Visva-Bharati, Department of Physics, Santiniketan (India); Bamba, Kazuharu [Fukushima University, Division of Human Support System, Faculty of Symbiotic Systems Science, Fukushima (Japan); Das, Sudipta [Visva-Bharati, Department of Physics, Santiniketan (India)

2017-01-15

The motivation of the present work is to reconstruct a dark energy model through the dimensionless dark energy function X(z), which is the dark energy density in units of its present value. In this paper, we have shown that a scalar field φ having a phenomenologically chosen X(z) can give rise to a transition from a decelerated to an accelerated phase of expansion for the universe. We have examined the possibility of constraining various cosmological parameters (such as the deceleration parameter and the effective equation of state parameter) by comparing our theoretical model with the latest Type Ia Supernova (SN Ia), Baryon Acoustic Oscillations (BAO) and Cosmic Microwave Background (CMB) radiation observations. Using the joint analysis of the SN Ia+BAO/CMB dataset, we have also reconstructed the scalar potential from the parametrized X(z). The relevant potential is found, a polynomial in φ. From our analysis, it has been found that the present model favors the standard ΛCDM model within 1σ confidence level. (orig.)

CuSn(OH)6 submicrospheres: Room-temperature synthesis, growth mechanism, and weak antiferromagnetic behavior

International Nuclear Information System (INIS)

Zhong, Sheng-Liang; Xu, Rong; Wang, Lei; Li, Yuan; Zhang, Lin-Fei

2011-01-01

Highlights: ► CuSn(OH) 6 spheres have been synthesized via an aqueous solution method at room temperature. ► The diameters of the CuSn(OH) 6 spheres can be tuned by adjusting the molar ratio of SnO 3 2− to Cu 2+ . ► The as-obtained CuSn(OH) 6 spheres are antiferromagnetic and have a weak spin-Peierls transition at about 78 K -- Abstract: CuSn(OH) 6 submicrospheres with diameters of 400–900 nm have been successfully fabricated using a simple aqueous solution method at room temperature. Influencing factors such as the dosage of reactants and reaction time on the preparation were systematically investigated. The products were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and differential thermal analysis (DTA). Results reveal that the CuSn(OH) 6 spheres are built from numerous nanoparticles. It is found that the diameter of CuSn(OH) 6 spheres can be readily tuned by adjusting the molar ratio of SnO 3 2− to Cu 2+ . A possible growth mechanism for the CuSn(OH) 6 submicrospheres has been proposed. Amorphous CuSnO 3 submicrospheres were obtained after thermal treatment of the CuSn(OH) 6 submicrospheres at 300 °C for 4 h. Standard magnetization measurements demonstrate that the CuSn(OH) 6 submicrospheres are antiferromagnetic and have a weak spin-Peierls transition at about 78 K.

Determination of a new structure type in the Sc-Fe-Ge-Sn system

Energy Technology Data Exchange (ETDEWEB)

Brgoch, Jakoah [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ran, Sheng [Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Thimmaiah, Srinivasa [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Canfield, Paul C. [Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Miller, Gordon J., E-mail: gmiller@iastate.edu [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States)

2013-01-05

Highlights: Black-Right-Pointing-Pointer A new structure type with the composition Sc{sub 4}Fe{sub 5}Ge{sub 6.10(3)}Sn{sub 1.47(2)}. Black-Right-Pointing-Pointer Crystallizes in the space group Immm (No. 71, oI144). Black-Right-Pointing-Pointer Sample obtained using a reactive Sn flux. Black-Right-Pointing-Pointer Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc-Fe-Ge-Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc{sub 4}Fe{sub 5}Ge{sub 6.10(3)}Sn{sub 1.47(2)} and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) A, b = 13.467(3) A, and c = 30.003(6) A. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc-Ge as well as Fe-Sn and Fe-Ge contacts can be assigned to this new structure type.

Sn-Sb-Se based binary and ternary alloys for phase change memory applications

Energy Technology Data Exchange (ETDEWEB)

Chung, Kyung-Min

2008-10-28

In this work, the effect of replacing Ge by Sn and Te by Se was studied for a systematic understanding and prediction of new potential candidates for phase change random access memories applications. The temperature dependence of the electrical/structural properties and crystallization kinetics of the Sn-Se based binary and Sn-Sb-Se based ternary alloys were determined and compared with those of the GeTe and Ge-Sb-Te system. The temperature dependence of electrical and structural properties were investigated by van der Pauw measurements, X-ray diffraction, X-ray reflectometry. By varying the heating rate, the Kissinger analysis has been used to determine the combined activation barrier for crystallization. To screen the kinetics of crystallization, a static laser tester was employed. In case of binary alloys of the type Sn{sub x}Se{sub 1-x}, the most interesting candidate is SnSe{sub 2} since it crystallizes into a single crystalline phase and has high electrical contrast and reasonably high activation energy for crystallization. In addition, the SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloy system also might be sufficient for data retention due to their higher transition temperature and activation energy for crystallization in comparison to GeTe-Sb{sub 2}Te{sub 3} system. Furthermore, SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloys have a higher crystalline resistivity. The desired rapid crystallization speed can be obtained for Sn{sub 1}Sb{sub 2}Se{sub 5} and Sn{sub 2}Sb{sub 2}Se{sub 7} alloys. (orig.)

Role of Cu in engineering the optical properties of SnO2 nanostructures: Structural, morphological and spectroscopic studies

Science.gov (United States)

Kumar, Virender; Singh, Kulwinder; Jain, Megha; Manju; Kumar, Akshay; Sharma, Jeewan; Vij, Ankush; Thakur, Anup

2018-06-01

We have carried out a systematic study to investigate the effect of Cu doping on the optical properties of SnO2 nanostructures synthesized by chemical route. Synthesized nanostructures were characterized using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), High resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray spectroscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV-visible and Photoluminescence (PL) spectroscopy. The Rietveld refinement analysis of XRD patterns of Cu-doped SnO2 samples confirmed the formation of single phase tetragonal rutile structure, however some localized distortion was observed for 5 mol% Cu-doped SnO2. Crystallite size was found to decrease with increase in dopant concentration. FE-SEM images indicated change in morphology of samples with doping. HR-TEM images revealed that synthesized nanostructures were nearly spherical and average crystallite size was in the range 12-21 nm. Structural defects, crystallinity and size effects on doping were investigated by Raman spectroscopy and results were complemented by FTIR spectroscopy. Optical band gap of samples was estimated from reflectance spectra. We have shown that band gap of SnO2 can be engineered from 3.62 to 3.82 eV by Cu doping. PL emission intensity increased as the doping concentration increased, which can be attributed to the development of defect states in the forbidden transition region of band gap of SnO2 with doping. We have also proposed a band model owing to defect states in SnO2 to explain the observed PL in Cu doped SnO2 nanostructures.

Quaternary selenostannates Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} and AGaSnSe{sub 4} (A=K, Rb, and Cs) through rapid cooling of melts. Kinetics versus thermodynamics in the polymorphism of AGaSnSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Hwang, S -J; Iyer, R G; Kanatzidis, M G

2004-10-01

The quaternary alkali-metal gallium selenostannates, Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} and AGaSnSe{sub 4} (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3) A, b=7.594(2) A, c=13.842(3) A, {beta}=118.730(4) deg., V=1226.7(5) A{sup 3}. {alpha}-KGaSnSe{sub 4} crystallizes in the tetragonal space group I4/mcm with a=8.186(5) A and c=6.403(5) A, V=429.1(5) A{sup 3}. {beta}-KGaSnSe{sub 4} crystallizes in the space group P2{sub 1}/c with cell constants a=7.490(2) A, b=12.578(3) A, c=18.306(5) A, {beta}=98.653(5) deg., V=1705.0(8) A{sup 3}. The unit cell of isostructural RbGaSnSe{sub 4} is a=7.567(2) A, b=12.656(3) A, c=18.277(4) A, {beta}=95.924(4) deg., V=1741.1(7) A{sup 3}. CsGaSnSe{sub 4} crystallizes in the orthorhombic space group Pmcn with a=7.679(2) A, b=12.655(3) A, c=18.278(5) A, V=1776.1(8) A{sup 3}. The structure of Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} consists of a polar three-dimensional network of trimeric (Sn,Ga){sub 3}Se{sub 9} units with Na atoms located in tunnels. The AGaSnSe{sub 4} possess layered structures. The compounds show nearly the same Raman spectral features, except for Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6}. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50 eV in Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} to 1.97 eV in CsGaSnSe{sub 4}. Cooling of the melts of KGaSnSe{sub 4} and RbGaSnSe{sub 4} produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called {gamma}-form (BaGa{sub 2}S{sub 4}-type) of these compounds.

Al-doped SnO2 nanocrystals from hydrothermal systems

International Nuclear Information System (INIS)

Jin Haiying; Xu Yaohua; Pang Guangsheng; Dong Wenjun; Wan Qiang; Sun Yan; Feng Shouhua

2004-01-01

Nanoparticles of Al-doped SnO 2 have been hydrothermally synthesized. The influences of the hydrothermal reaction time, the molar ratio of Sn/Al as well as the pH value of the solution have been studied. During the hydrothermal synthesis, the particle's core is rich in Sn and the surface is rich in Al. The Al-rich surface prevents the particles from further growing up either in the hydrothermal condition or during the calcination at 600 deg. C for a short period of time. The optimal hydrothermal synthesis condition of the nanoparticles is pH 5, Sn/Al=4:1 and 12 h at 160 deg. C. The products have been studied by XRD, TEM and 27 Al solid-state NMR

Study of the thermoelectric properties of Pb{sub (1-x)} Sn{sub x} Te; Contribution a l'etude des proprietes thermoelectriques de solutions Pb{sub (1-x)}Sn{sub x} Te

Energy Technology Data Exchange (ETDEWEB)

Borde, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-04-15

The present work concerns the study of the electrical properties (thermoelectric power, electrical resistivity and Hall coefficient) of PbTe and SnTe crystals and of solid polycrystalline solutions of Pb{sub 1-x} Sn{sub x} Te (0.1 < x < 0.6) between 80 and 800 deg. K. From the temperature dependence of these properties and the effect of the addition, it has been possible to characterize the semiconductor nature of these solutions, and to approach their band structure; in particular the forbidden gap behaviour in these solutions has been analyzed and evidence for the existence of a double valence band has been obtained. (author) [French] Le present travail est relatif a l'etude des proprietes electriques, en particulier du pouvoir thermoelectrique de la resistivite electrique et du coefficient de Hall, de cristaux PbTe et SnTe, et de solutions solides polycristallines Pb{sub 1-x} Sn{sub x} Te (0,1 {<=} x {<=} 0,6) entre 80 et 800 deg. K. La variation de ces proprietes avec la temperature, ainsi que l'effet de l'addition de Sn sur celles-ci, ont permis de preciser le caractere semiconducteur de ces solutions, et contribue a la determination de leur structure de bandes, en particulier le comportement de la bande interdite dans ces solutions a ete analyse et l'existence d'une double bande de valence mise en evidence. (auteur)

Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+xMn50Sn11−x(x ⩽ 2) alloys

Science.gov (United States)

Prasanna, A A; Ram, Shanker

2013-01-01

Ni39+xMn50Sn11−x (x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ∼15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2), whereas an austenite cubic L21 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x ≽ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite–austenite (or reverse) phase transition. A net residual enthalpy change ΔHM↔A = −0.12 J g−1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (–)26% at 10 T is observed together with a large entropy change of 11.8 mJ g−1 K−1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHM↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features. PMID:27877562

Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+xMn50Sn11−x(x ≤ 2 alloys

Directory of Open Access Journals (Sweden)

A A Prasanna and Shanker Ram

2013-01-01

Full Text Available Ni39+xMn50Sn11−x (x = 0.5, 1.0, 1.5 and 2 alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ~15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2, whereas an austenite cubic L21 phase turns up at smaller x ≤ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x ≥ 1.5 with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite–austenite (or reverse phase transition. A net residual enthalpy change ΔHM↔A = −0.12 J g−1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (–26% at 10 T is observed together with a large entropy change of 11.8 mJ g−1 K−1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHM↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.

Moessbauer study of supertransferred hyperfine field of /sup 119/Sn (Sn/sup 4 +/) in Casub(1-x)Srsub(x)MnO/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Takano, M [Konan Univ., Kobe (Japan). Faculty of Science; Takeda, Y; Shimada, M; Matsuzawa, T; Shinjo, T

1975-09-01

Casub(1-x)Srsub(x)Mnsub(0.99)Snsub(0.01)O/sub 3/(0<=x<=1) with (nearly) cubic perovskite structures were prepared and the magnetic hyperfine fields of /sup 119/Sn (Sn/sup 4 +/) were measured by the Moessbauer effect. The hyperfine fields arise from unpaired s electron spin densities transferred from Mn/sup 4 +/ ions (supertransferred hyperfine interaction). The hyperfine field for a tin ion was found to depend linearly upon the numbers of Ca/sup 2 +/ and Sr/sup 2 +/ ions in the neighboring divalent cation sites, with proportional coefficients having opposite signs. To explain experimental results two kinds of spin transfer processes contributing to the hyperfine field oppositely to each other have been considered, and spin transfer via a divalent cation is emphasized particularly. The hyperfine field at 0 K for Sn/sup 4 +/ in CaMnO/sub 3/ is -75 kOe, while +20 kOe for Sn/sup 4 +/ in SrMnO/sub 3/.

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

Structure of Sn1−xGex random alloys as obtained from the coherent potential approximation

KAUST Repository

Pulikkotil, J. J.

2011-08-09

The structure of the Sn1−xGex random alloys is studied using density functional theory and the coherent potential approximation. We report on the deviation of the Sn1−xGex alloys from Vegard’s law, addressing their full compositional range. The findings are compared to the related Si1−xGex alloys and to experimental results. Interestingly, the deviation from Vegard’s law is quantitatively and qualitatively different between the Sn1−xGex and Si1−xGex alloys. An almost linear dependence of the bulk modulus as a function of composition is found for Si1−xGex, whereas for Sn1−xGex the dependence is strongly nonlinear.

Magnetic anisotropy in Pb_{1-x-y}Sn_{y}Mn_{x}Te studied by ferromagnetic resonance

NARCIS (Netherlands)

Eggenkamp, P.J.T.; Story, T.; Swüste, C.H.W.; Swagten, H.J.M.; Jonge, de W.J.M.

1993-01-01

Proceedings of the XXII International School of Semiconducting Compounds, Jaszowiec 1993 We will report on the anisotropy in (Pb)SnMnTe, studied by ferromagnetic resonance. We have found a cubic anisotropy with a = 73 × 10-4 cm-1 for Sn1-xMnxTe and a = 200 × 10-4 cm-1 for Pb0.28-xSn0.72MnxTe. We

1g(9/2), 1f(5/2), and 1f(7/2) neutron inner hole responses in Sn-115 and Sn-119 via the ((d)over-right-arrow,t) reaction at E-d=200 MeV

NARCIS (Netherlands)

Langevin-Joliot, H; Van de Wiele, J; Guillot, J; Gerlic, E; Rosier, LH; Willis, A; Djalali, C; Morlet, M; Tomasi-Gustafsson, E; Blasi, N; Micheletti, S; van der Werf, SY

Neutron inner hole responses in Sn-115 and Sn-119 nuclei have been studied via the ((d) over right arrow ,t) reaction at E-d=200 MeV using a polarized beam with both vector and tensor components. One-step pickup observables corresponding to the overlapping 1g(9/2), 1f(5/2), and 1f(7/2) responses

Metabolism of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine in the human neutrophil

International Nuclear Information System (INIS)

Triggiani, M.; D'Souza, D.M.; Chilton, F.H.

1991-01-01

The biosynthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-2-acetyl-GPC) together with that of 1-alkyl-2-acetyl-GPC (platelet-activating factor) has been demonstrated in a variety of inflammatory cells and tissues. It has been hypothesized that the relative proportion of these phospholipids produced upon cell activation may be influenced by their rates of catabolism. We studied the catabolism of 1-acyl-2-acetyl-GPC in resting and activated human neutrophils and compared it to that of 1-alkyl-2-acetyl-GPC. Neutrophils rapidly catabolize both 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC; however, the rate of catabolism of 1-acyl-2-acetyl-GPC is approximately 2-fold higher than that of 1-alkyl-2-acetyl-GPC. In addition, most of 1-acyl-2-acetyl-GPC is catabolized through a pathway different from that of 1-alkyl-2-acetyl-GPC. The main step in the catabolism of 1-acyl-2-acetyl-GPC is the removal of the long chain at the sn-1 position; the long chain residue is subsequently incorporated either into triglycerides or into phosphatidylcholine. The 1-lyso-2-acetyl-GPC formed in this reaction is then further degraded to glycerophosphocholine, choline, or phosphocholine. 1-Acyl-2-acetyl-GPC is also catabolized, to a lesser extent, through deacetylation at the sn-2 position and reacylation with a long chain fatty acid. Stimulation of neutrophils by A23187 results in a higher rate of catabolism of 1-acyl-2-acetyl-GPC by increasing both the removal of the long chain at the sn-1 position and the deacetylation-reacylation at the sn-2 position. In a broken cell preparation, the cytosolic fraction of the neutrophil was shown to contain an enzyme activity which cleaved the sn-1 position of 1-acyl-2-acetyl-GPC and 1-acyl-2-lyso-GPC but not of 1,2-diacyl-GPC