A multiple-field coupled resistive transition model for superconducting Nb3Sn

Directory of Open Access Journals (Sweden)

Lin Yang

2016-12-01

Full Text Available A study on the superconducting transition width as functions of the applied magnetic field and strain is performed in superconducting Nb3Sn. A quantitative, yet universal phenomenological resistivity model is proposed. The numerical simulation by the proposed model shows predicted resistive transition characteristics under variable magnetic fields and strain, which in good agreement with the experimental observations. Furthermore, a temperature-modulated magnetoresistance transition behavior in filamentary Nb3Sn conductors can also be well described by the given model. The multiple-field coupled resistive transition model is helpful for making objective determinations of the high-dimensional critical surface of Nb3Sn in the multi-parameter space, offering some preliminary information about the basic vortex-pinning mechanisms, and guiding the design of the quench protection system of Nb3Sn superconducting magnets.

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.

Comparison of mechanical concepts for $Nb_3Sn$ high field accelerator magnets

CERN Document Server

AUTHOR|(CDS)2084469; Peter, Schmolz

Several magnets using Nb$_{3}$Sn as conductor are currently developed at CERN; these magnets are either slated for future updates of the LHC or for research purposes relating to future accelerators. The mechanical structure is one of the challenging aspects of superconducting high-field magnets. The main purpose of the mechanical structure is to keep the coils in compression till the emergence of the highest electromagnetic forces that are developed in the ultimate field of the magnet. Any loss of pre-compression during the magnet’s excitation would cause too large deformation of the coil and possibly a quench in the conductor owing to relative movements of strands in contact associated with excessive local heat release. However, too high pre-compression would overstrain the conductor and thereby limit the performance of the magnet. This thesis focuses on the mechanical behaviour of three of these magnets. All of them are based on different mechanical designs, “bladder and key” and “collar-based”, ...

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-03-01

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

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.

Tunable SnO2 Nanoribbon by Electric Fields and Hydrogen Passivation

Directory of Open Access Journals (Sweden)

Xin-Lian Chen

2017-01-01

Full Text Available Under external transverse electronic fields and hydrogen passivation, the electronic structure and band gap of tin dioxide nanoribbons (SnO2NRs with both zigzag and armchair shaped edges are studied by using the first-principles projector augmented wave (PAW potential with the density function theory (DFT framework. The results showed that the electronic structures of zigzag and armchair edge SnO2NRs exhibit an indirect semiconducting nature and the band gaps demonstrate a remarkable reduction with the increase of external transverse electronic field intensity, which demonstrate a giant Stark effect. The value of the critical electric field for bare Z-SnO2NRs is smaller than A-SnO2NRs. In addition, the different hydrogen passivation nanoribbons (Z-SnO2NRs-2H and A-SnO2NRs-OH show different band gaps and a slightly weaker Stark effect. The band gap of A-SnO2NRs-OH obviously is enhanced while the Z-SnO2NRs-2H reduce. Interestingly, the Z-SnO2NRs-OH presented the convert of metal-semiconductor-metal under external transverse electronic fields. In the end, the electronic transport properties of the different edges SnO2NRs are studied. These findings provide useful ways in nanomaterial design and band engineering for spintronics.

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

Assembly and Test of HD2, a 36 mm bore high field Nb3Sn Dipole Magnet

International Nuclear Information System (INIS)

Ferracin, P.; Bingham, B.; Caspi, S.; Cheng, D.W.; Dietderich, D.R.; Felice, H.; Godeke, A.; Hafalia, A.R.; Hannaford, C.R.; Joseph, J.; Lietzke, A.F.; Lizarazo, J.; Sabbi, G.; Trillaud, F.; Wang, X.

2008-01-01

We report on the fabrication, assembly, and test of the Nb 3 Sn dipole magnet HD2. The magnet, aimed at demonstrating the application of Nb 3 Sn superconductor in high field accelerator-type dipoles, features a 36 mm clear bore surrounded by block-type coils with tilted ends. The coil design is optimized to minimize geometric harmonics in the aperture and the magnetic peak field on the conductor in the coil ends. The target bore field of 15 T at 4.3 K is consistent with critical current measurements of extracted strands. The coils are horizontally pre-stressed during assembly using an external aluminum shell pre-tensioned with water-pressurized bladders. Axial pre-loading of the coil ends is accomplished through two end plates and four aluminum tension rods. The strain in coil, shell, and rods is monitored with strain gauges during assembly, cool-down and magnet excitation, and compared with 3D finite element computations. Magnet's training performance, quench locations, and ramp-rate dependence are then analyzed and discussed.

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)

Field emission from patterned SnO2 nanostructures

International Nuclear Information System (INIS)

Zhang Yongsheng; Yu Ke; Li Guodong; Peng Deyan; Zhang Qiuxiang; Hu Hongmei; Xu Feng; Bai Wei; Ouyang Shixi; Zhu Ziqiang

2006-01-01

A simple and reliable method has been developed for synthesizing finely patterned tin dioxide (SnO 2 ) nanostructure arrays on silicon substrates. A patterned Au catalyst film was prepared on the silicon wafer by radio frequency (RF) magnetron sputtering and photolithographic patterning processes. The patterned SnO 2 nanostructures arrays, a unit area is of ∼500 μm x 200 μm, were synthesized via vapor phase transport method. The surface morphology and composition of the as-synthesized SnO 2 nanostructures were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanism of formation of SnO 2 nanostructures was also discussed. The measurement of field emission (FE) revealed that the as-synthesized SnO 2 nanorods, nanowires and nanoparticles arrays have a lower turn-on field of 2.6, 3.2 and 3.9 V/μm, respectively, at the current density of 0.1 μA/cm 2 . This approach must have a wide variety of applications such as fabrications of micro-optical components and micropatterned oxide thin films used in FE-based flat panel displays, sensor arrays and so on

Analysis of Uncertainties in Protection Heater Delay Time Measurements and Simulations in Nb$_{3}$Sn High-Field Accelerator Magnets

CERN Document Server

Salmi, Tiina; Marchevsky, Maxim; Bajas, Hugo; Felice, Helene; Stenvall, Antti

2015-01-01

The quench protection of superconducting high-field accelerator magnets is presently based on protection heaters, which are activated upon quench detection to accelerate the quench propagation within the winding. Estimations of the heater delay to initiate a normal zone in the coil are essential for the protection design. During the development of Nb3Sn magnets for the LHC luminosity upgrade, protection heater delays have been measured in several experiments, and a new computational tool CoHDA (Code for Heater Delay Analysis) has been developed for heater design. Several computational quench analyses suggest that the efficiency of the present heater technology is on the borderline of protecting the magnets. Quantifying the inevitable uncertainties related to the measured and simulated delays is therefore of pivotal importance. In this paper, we analyze the uncertainties in the heater delay measurements and simulations using data from five impregnated high-field Nb3Sn magnets with different heater geometries. ...

Analysis of Uncertainties in Protection Heater Delay Time Measurements and Simulations in Nb$_{3}$Sn High-Field Accelerator Magnets

CERN Document Server

Salmi, Tiina; Marchevsky, Maxim; Bajas, Hugo; Felice, Helene; Stenvall, Antti

2015-01-01

The quench protection of superconducting high-field accelerator magnets is presently based on protection heaters, which are activated upon quench detection to accelerate the quench propagation within the winding. Estimations of the heater delay to initiate a normal zone in the coil are essential for the protection design. During the development of Nb$_{3}$Sn magnets for the LHC luminosity upgrade, protection heater delays have been measured in several experiments, and a new computational tool CoHDA (Code for Heater Delay Analysis) has been developed for heater design. Several computational quench analyses suggest that the efficiency of the present heater technology is on the borderline of protecting the magnets. Quantifying the inevitable uncertainties related to the measured and simulated delays is therefore of pivotal importance. In this paper, we analyze the uncertainties in the heater delay measurements and simulations using data from five impregnated high-field Nb$_{3}$Sn magnets with different heater ge...

2D/3D quench simulation using ANSYS for epoxy impregnated Nb3Sn high field magnets

Energy Technology Data Exchange (ETDEWEB)

Ryuji Yamada et al.

2002-09-19

A quench program using ANSYS is developed for the high field collider magnet for three-dimensional analysis. Its computational procedure is explained. The quench program is applied to a one meter Nb{sub 3}Sn high field model magnet, which is epoxy impregnated. The quench simulation program is used to estimate the temperature and mechanical stress inside the coil as well as over the whole magnet. It is concluded that for the one meter magnet with the presented cross section and configuration, the thermal effects due to the quench is tolerable. But we need much more quench study and improvements in the design for longer magnets.

Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands

CERN Document Server

Bordini, B; Fehér, S; Rossi, L; Zlobin, A V

2008-01-01

Recent advancements in the critical current density (Jc) of Nb$_{3}$Sn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc Nb$_{3}$Sn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized Nb$_{3}$Sn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizin...

Study of high field Nb3Sn superconducting dipoles: electrical insulation based made of ceramic and magnetic design

International Nuclear Information System (INIS)

Rochepault, E.

2012-01-01

In the framework of LHC upgrades, significant efforts are provided to design accelerator magnets using the superconducting alloy Nb 3 Sn, which allows to reach higher magnetic fields (≥12 T). The aim of this thesis is to propose new computation and manufacturing methods for high field Nb 3 Sn dipoles. A ceramic insulation, previously designed at CEA Saclay, has been tested for the first time on cables, in an accelerator magnet environment. Critical current measures, under magnetic field and mechanical stress, have been carried out in particular. With this test campaign, the current ceramic insulation has been shown to be too weak mechanically and the critical current properties are degraded. Then a study has been conducted, with the objective to improve the mechanical strength of the insulation and better distribute the stress inside the cable. Methods of magnetic design have also been proposed, in order to optimize the coils shape, while fulfilling constraints of field homogeneity, operational margins, forces minimization... Consequently, several optimization codes have been set up. They are based on new methods using analytical formulas. A 2D code has first been written for block designs. Then two 3D codes have been realized for the optimization of dipole ends. The former consists in modeling the coil with elementary blocs and the latter is based on a modeling of the superconducting cables with ribbons. These optimization codes allowed to propose magnetic designs for high field accelerator magnets. (author) [fr

Progress with High-Field Superconducting Magnets for High-Energy Colliders

Science.gov (United States)

Apollinari, Giorgio; Prestemon, Soren; Zlobin, Alexander V.

2015-10-01

One of the possible next steps for high-energy physics research relies on a high-energy hadron or muon collider. The energy of a circular collider is limited by the strength of bending dipoles, and its maximum luminosity is determined by the strength of final focus quadrupoles. For this reason, the high-energy physics and accelerator communities have shown much interest in higher-field and higher-gradient superconducting accelerator magnets. The maximum field of NbTi magnets used in all present high-energy machines, including the LHC, is limited to ˜10 T at 1.9 K. Fields above 10 T became possible with the use of Nb3Sn superconductors. Nb3Sn accelerator magnets can provide operating fields up to ˜15 T and can significantly increase the coil temperature margin. Accelerator magnets with operating fields above 15 T require high-temperature superconductors. This review discusses the status and main results of Nb3Sn accelerator magnet research and development and work toward 20-T magnets.

High field superconductor development and understanding

Energy Technology Data Exchange (ETDEWEB)

Larbalestier, David C. [Florida State Univ., Tallahassee, FL (United States); Lee, Peter J. [Florida State Univ., Tallahassee, FL (United States); Tarantini, Chiara [Florida State Univ., Tallahassee, FL (United States)

2014-09-28

All present circular accelerators use superconducting magnets to bend and to focus the particle beams. The most powerful of these machines is the large hadron collider (LHC) at CERN. The main ring dipole magnets of the LHC are made from Nb-Ti but, as the machine is upgraded to higher luminosity, more powerful magnets made of Nb₃Sn will be required. Our work addresses how to make the Nb₃Sn conductors more effective and more suitable for use in the LHC. The most important property of the superconducting conductor used for an accelerator magnet is that it must have very high critical current density, the property that allows the generation of high magnetic fields in small spaces. Nb₃Sn is the original high field superconductor, the material which was discovered in 1960 to allow a high current density in the field of about 9 T. For the high luminosity upgrade of the LHC, much higher current densities in fields of about 12 Tesla will be required. The critical value of the current density is of order 2600 A/mm² in a field of 12 Tesla. But there are very important secondary factors that complicate the attainment of this critical current density. The first is that the effective filament diameter must be no larger than about 40 µm. The second factor is that 50% of the cross-section of the Nb₃Sn conductor that is pure copper must be protected from any poisoning by any Sn leakage through the diffusion barrier that protects the package of niobium and tin from which the Nb₃Sn is formed by a high temperature reaction. These three, somewhat conflicting requirements, mean that optimization of the conductor is complex. The work described in this contract report addresses these conflicting requirements. They show that very sophisticated characterizations can uncover the way to satisfy all 3 requirements and they also suggest that the ultimate optimization of Nb₃Sn is still not yet in sight

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

Characterization of amorphous multilayered ZnO-SnO2 heterostructure thin films and their field effect electronic properties

International Nuclear Information System (INIS)

Lee, Su-Jae; Hwang, Chi-Sun; Pi, Jae-Eun; Yang, Jong-Heon; Oh, Himchan; Cho, Sung Haeng; Cho, Kyoung-Ik; Chu, Hye Yong

2014-01-01

Multilayered ZnO-SnO 2 heterostructure thin films were produced using pulsed laser ablation of pie-shaped ZnO-SnO 2 oxides target, and their structural and field effect electronic transport properties were investigated as a function of the thickness of the ZnO and SnO 2 layers. The films have an amorphous multilayered heterostructure composed of the periodic stacking of the ZnO and SnO 2 layers. The field effect electronic properties of amorphous multilayered ZnO-SnO 2 heterostructure thin film transistors (TFTs) are highly dependent on the thickness of the ZnO and SnO 2 layers. The highest electron mobility of 37 cm 2 /V s, a low subthreshold swing of a 0.19 V/decade, a threshold voltage of 0.13 V, and a high drain current on-to-off ratio of ∼10 10 obtained for the amorphous multilayered ZnO(1.5 nm)-SnO 2 (1.5 nm) heterostructure TFTs. These results are presumed to be due to the unique electronic structure of an amorphous multilayered ZnO-SnO 2 heterostructure film consisting of ZnO, SnO 2 , and ZnO-SnO 2 interface layers

Enhancement of field emission and photoluminescence properties of graphene-SnO2 composite nanostructures.

Science.gov (United States)

Ding, Jijun; Yan, Xingbin; Li, Jun; Shen, Baoshou; Yang, Juan; Chen, Jiangtao; Xue, Qunji

2011-11-01

In this study, the SnO(2) nanostructures and graphene-SnO(2) (G-SnO(2)) composite nanostructures were prepared on n-Si (100) substrates by electrophoretic deposition and magnetron sputtering techniques. The field emission of SnO(2) nanostructures is improved largely by depositing graphene buffer layer, and the field emission of G-SnO(2) composite nanostructures can also further be improved by decreasing sputtering time of Sn nanoparticles to 5 min. The photoluminescence (PL) spectra of the SnO(2) nanostructures revealed multipeaks, which are consistent with previous reports except for a new peak at 422 nm. Intensity of six emission peaks increased after depositing graphene buffer layer. Our results indicated that graphene can also be used as buffer layer acting as interface modification to simultaneity improve the field emission and PL properties of SnO(2) nanostructures effectively.

Industrial powder metallurgy processing for production of high field Nb3Sn

International Nuclear Information System (INIS)

Hecker, A.; Gregory, E.; Wong, J.; Thieme, C.L.H.; Foner, S.

1988-01-01

Technology transfer is discussed for fabricating Nb 3 Sn(Ti) via powder metallurgy methods from laboratory scale production at MIT to industrial production at Supercon Inc. Industrial production techniques such as hydrostatic extrusion and drawing have produced superconducting wires with promising critical current densities in preliminary field measurements. Initial steps toward process modification and optimization to improve the commercial feasibility of the powder metallurgy process are evaluated. These modifications are aimed at reducing production time and increasing process flexibility

Mechanical properties of high-current multifilamentary Nb3Sn conductors

International Nuclear Information System (INIS)

Scanlan, R.M.; Hoard, R.W.; Cornish, D.N.; Zbasnik, J.P.

1980-01-01

Nb 3 Sn is a strain-sensitive superconductor which exhibits large changes in properties for strains of less than 1 percent. The critical current density at 12 T undergoes a reversible degradation of a factor of two for compressive strains of about 1 percent and undergoes an irreversible degradation for tensile strains on the Nb 3 Sn greater than 0.2 percent. Consequently, the successful application of Nb 3 Sn in large high-field magnets requires a complete understanding of the mechanical properties of the conductor. One conductor which is being used for many applications consists of filaments of Nb 3 Sn in a bronze matrix, and much progress has been made in understanding the mechanical behavior of this composite. The Nb 3 Sn filaments are placed in compression due to the differential thermal contraction between Nb 3 Sn and bronze which occurs when the composite is cooled from the Nb 3 Sn formation temperature (typically 700 0 C) to the 4.2 0 K operating temperature. The general behavior of the critical current when this conductor is subjected to a tensile stress is an increase to a maximum when the compressive strain on the Nb 3 Sn is relieved, followed by a decrease as the Nb 3 Sn filemants are placed in tension. The degree of precompression is controlled largely by the ratio of bronze to Nb 3 Sn in the conductor

Few-layer SnSe{sub 2} transistors with high on/off ratios

Energy Technology Data Exchange (ETDEWEB)

Pei, Tengfei; Bao, Lihong, E-mail: lhbao@iphy.ac.cn; Wang, Guocai; Ma, Ruisong; Yang, Haifang; Li, Junjie; Gu, Changzhi; Du, Shixuan; Gao, Hong-jun [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Pantelides, Sokrates [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Material Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381 (United States)

2016-02-01

We report few-layer SnSe{sub 2} field effect transistors (FETs) with high current on/off ratios. By trying different gate configurations, 300 nm SiO{sub 2} and 70 nm HfO{sub 2} as back gate only and 70 nm HfO{sub 2} as back gate combined with a top capping layer of polymer electrolyte, few-layer SnSe{sub 2} FET with a current on/off ratio of 10{sup 4} can be obtained. This provides a reliable solution for electrically modulating quasi-two-dimensional materials with high electron density (over 10{sup 13} cm{sup −2}) for field-effect transistor applications.

submitter Optimization of Nb$_{3}$Sn Rutherford Cables Geometry for the High Luminosity LHC

CERN Document Server

Fleiter, Jerome; Bonasia, Angelo; Bordini, Bernardo; Richter, David

2017-01-01

The quadrupole and dipole magnets for the LHC High Luminosity (HL-LHC) upgrade will be based on Nb$_{3}$Sn Rutherford cables that operate at 1.9 K and experience magnetic fields of up to about 12 T. An important step in the design of these magnets is the development of the high aspect ratio Nb$_{3}$Sn cables to achieve the nominal field with sufficient margin. The strong plastic deformation of unreacted $Nb_3Sn$ strands during the Rutherford cabling process may induce non negligible $I_c$ and RRR degradation. In this paper, the cabling degradation is investigated as a function of the cable geometry for both PIT and RRP conductors. Based on this analysis, new baseline geometries for both 11 T and QXF magnets of HL-LHC are proposed.

submitter Optimization of Nb$_{3}$Sn Rutherford Cables Geometry for the High Luminosity LHC

CERN Document Server

Fleiter, Jerome; Bonasia, Angelo; Bordini, Bernardo; Richter, David

2017-01-01

The quadrupole and dipole magnets for the LHC High Luminosity (HL-LHC) upgrade will be based on Nb3Sn Rutherford cables that operate at 1.9 K and experience magnetic fields of up to about 12 T. An important step in the design of these magnets is the development of the high aspect ratio Nb3Sn cables to achieve the nominal field with sufficient margin. The strong plastic deformation of unreacted $Nb_3Sn$ strands during the Rutherford cabling process may induce non negligible $I_c$ and RRR degradation. In this paper, the cabling degradation is investigated as a function of the cable geometry for both PIT and RRP conductors. Based on this analysis, new baseline geometries for both 11 T and QXF magnets of HL-LHC are proposed.

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/.

High-field Magnet Development toward the High Luminosity LHC

Energy Technology Data Exchange (ETDEWEB)

Apollinari, Giorgio [Fermilab

2014-07-01

The upcoming Luminosity upgrade of the LHC (HL-LHC) will rely on the use of Accelerator Quality Nb3Sn Magnets which have been the focus of an intense R&D effort in the last decade. This contribution will describe the R&D and results of Nb3Sn Accelerator Quality High Field Magnets development efforts, with emphasis on the activities considered for the HL-LHC upgrades.

Synthesis and room-temperature ferromagnetic properties of single-crystalline Co-doped SnO2 nanocrystals via a high magnetic field

International Nuclear Information System (INIS)

Xu Yongbin; Tang Yongjun; Li Chuanjun; Cao Guanghui; Ren Weili; Xu Hui; Ren Zhongming

2009-01-01

The magnetic field-assisted approach has been used in the synthesis of Co-doped SnO 2 diluted magnetic semiconductor nanocrystals. By annealing under the condition with or without magnetic field, 1D growth of the nanostructures can be induced, and the magnetic properties of the obtained nanocrystals are improved. Various techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), UV-visible spectrometry (UV-vis), Raman spectrometry and vibrating sample magnetometer (VSM) have been used to characterize the obtained products. The results show that the magnetic field holds important effects on the crystal growth of the Co-doped SnO 2 nanostructures, and improvement of magnetic properties. The intrinsic reasons are discussed.

Peak Fields of Nb$_{3}$Sn Superconducting Undulators and a Scaling Law

CERN Document Server

Kim, S H

2005-01-01

The peak fields on the beam axis and the maximum fields in the conductor of Nb$_{3}$Sn superconducting undulators (SCUs) were calculated for an undulator period length of 16 mm. Using a simple scaling law for SCUs [1], the peak fields, as well as the conductor maximum fields and the current densities, were calculated for a period range of 8 to 32 mm. The critical current densities of commercially available Nb$_{3}$Sn superconducting strands were used for the calculations. The achievable peak fields are limited mainly by the flux-jump instabilities at low fields. The possible or feasible peak field will also be compared with that achieved in prototype development of SCUs.

Development of manufacturing capability for the fabrication of the Nb3Sn superconductor for the High Field Test Facility. Final report

International Nuclear Information System (INIS)

Spencer, C.R.

Construction of High Field Test Facility (HFTF) at Lawrence Livermore Laboratory (LLNL) requires an extended surface Nb 3 Sn superconductor cable of carrying currents in excess of 7500 amperes in a 12 Tesla magnetic field. This conductor consists of a 5.4 mm x 11.0 mm superconducting core onto whose broad surfaces are soldered embossed oxygen free copper strips. Two different core designs have been developed and the feasibility of each design evaluated. Equipment necessary to produce the conductor were developed and techniques of production were explored

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.

Studies on Nb3Sn field coils for superconducting machine

International Nuclear Information System (INIS)

Fujino, H.; Nose, S.

1981-01-01

This paper describes experimental studies on several coils wound with multifilamentary (MF) Nb 3 Sn cables with reinforcing strip for superconducting rotating machine application. To use a Nb 3 Sn superconductor to field winding of a rotating machine, several coil performances of pre-reacted, bronze processed and stranded MF Nb 3 Sn cables were investigated, mainly in relation to stress effect. Bending strain up to 0.64% in strand and winding stress of 5 kg/mm 2 have resulted in nondegradation in coil performance. A pair of impregnated race-track coils designed for a 30 MVA synchronous condenser was energized successfully up to 80% of critical current without quench. 8 refs

Study of the hyperfine magnetic field at Ta181 site in the Heusler Co2 Sc Sn, Co2 Sc Ga and Co2 Hf Sn alloys

International Nuclear Information System (INIS)

Attili, R.N.

1992-01-01

The hyperfine magnetic fields acting on 181 Ta nuclei at the Sc and Hf sites have been measured in Heusler alloys Co 2 Sc Sn and Co 2 Sc Ga and Co 2 Hf Sn using the Time Differential Perturbed γ-γ Angular Correlation (TDPAC) technique. The measurements were carried out using an automatic spectrometer consisting of two Ba F 2 detectors and the conventional electronics. The magnitude of hyperfine magnetic field at 181 Ta was measured for all the alloys. The signs of the were determined in the cases of Co 2 Sc Sn and Co 2 Hf Sn alloys by performing the Perturbed Angular Correlation measurements with an external polarizing magnetic field of ≅ 5 k Gauss. The hyperfine magnetic fields obtained are -187,6± 3,3 and 90,0 ± 2,1 kOe measured at 77 K for Co 2 Sc Sn and Co 2 Sc Ga alloys respectively, and -342,4 ± 10,1 kOe measured at the room temperature for Co 2 Hf Sn alloy. These results are discussed and compared with the hyperfine magnetic field systematics in Co-based Heusler alloy. (author)

Evidence from EXAFS for Different Ta/Ti Site Occupancy in High Critical Current Density Nb3Sn Superconductor Wires.

Science.gov (United States)

Heald, Steve M; Tarantini, Chiara; Lee, Peter J; Brown, Michael D; Sung, ZuHawn; Ghosh, Arup K; Larbalestier, David C

2018-03-19

To meet critical current density, J c , targets for the Future Circular Collider (FCC), the planned replacement for the Large Hadron Collider (LHC), the high field performance of Nb 3 Sn must be improved, but champion J c values have remained static for the last 10 years. Making the A15 phase stoichiometric and enhancing the upper critical field H c2 by Ti or Ta dopants are the standard strategies for enhancing high field performance but detailed recent studies show that even the best modern wires have broad composition ranges. To assess whether further improvement might be possible, we employed Extended X-ray Absorption Fine Structure (EXAFS) to determine the lattice site location of dopants in modern high-performance Nb 3 Sn strands with J c values amongst the best so far achieved. Although Ti and Ta primarily occupy the Nb sites in the A15 structure, we also find significant Ta occupancy on the Sn site. These findings indicate that the best performing Ti-doped stand is strongly sub-stoichiometric in Sn and that antisite disorder likely explains its high average H c2 behavior. These new results suggest an important role for dopant and antisite disorder in minimizing superconducting property distributions and maximizing high field J c properties.

Strain dependence of the critical current and critical field in multifilamentary Nb3Sn composites

International Nuclear Information System (INIS)

Ekin, J.W.

1979-01-01

High-J/sub c/ multifilamentary Nb 3 Sn superconductors with widely varying amounts of prestrain and critical field values can be characterized fairly accurately by a single normalized critical field-strain relationship. Such a relationship permits first order prediction of critical-current degradation at arbitrary magnetic field magnitudes with knowledge of only two parameters for any conductor, the prestrain and the maximum critical field. Some of the conductor-fabrication factors affecting the parameters are considered

Tunable SnSe2 /WSe2 Heterostructure Tunneling Field Effect Transistor.

Science.gov (United States)

Yan, Xiao; Liu, Chunsen; Li, Chao; Bao, Wenzhong; Ding, Shijin; Zhang, David Wei; Zhou, Peng

2017-09-01

The burgeoning 2D semiconductors can maintain excellent device electrostatics with an ultranarrow channel length and can realize tunneling by electrostatic gating to avoid deprivation of band-edge sharpness resulting from chemical doping, which make them perfect candidates for tunneling field effect transistors. Here this study presents SnSe 2 /WSe 2 van der Waals heterostructures with SnSe 2 as the p-layer and WSe 2 as the n-layer. The energy band alignment changes from a staggered gap band offset (type-II) to a broken gap (type-III) when changing the negative back-gate voltage to positive, resulting in the device operating as a rectifier diode (rectification ratio ~10 4 ) or an n-type tunneling field effect transistor, respectively. A steep average subthreshold swing of 80 mV dec -1 for exceeding two decades of drain current with a minimum of 37 mV dec -1 at room temperature is observed, and an evident trend toward negative differential resistance is also accomplished for the tunneling field effect transistor due to the high gate efficiency of 0.36 for single gate devices. The I ON /I OFF ratio of the transfer characteristics is >10 6 , accompanying a high ON current >10 -5 A. This work presents original phenomena of multilayer 2D van der Waals heterostructures which can be applied to low-power consumption devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proof-of-principle demonstration of Nb3Sn superconducting radiofrequency cavities for high Q0 applications

Science.gov (United States)

Posen, S.; Liepe, M.; Hall, D. L.

2015-02-01

Many future particle accelerators require hundreds of superconducting radiofrequency (SRF) cavities operating with high duty factor. The large dynamic heat load of the cavities causes the cryogenic plant to make up a significant part of the overall cost of the facility. This contribution can be reduced by replacing standard niobium cavities with ones coated with a low-dissipation superconductor such as Nb3Sn. In this paper, we present results for single cell cavities coated with Nb3Sn at Cornell. Five coatings were carried out, showing that at 4.2 K, high Q0 out to medium fields was reproducible, resulting in an average quench field of 14 MV/m and an average 4.2 K Q0 at quench of 8 × 109. In each case, the peak surface magnetic field at quench was well above Hc1, showing that it is not a limiting field in these cavities. The coating with the best performance had a quench field of 17 MV/m, exceeding gradient requirements for state-of-the-art high duty factor SRF accelerators. It is also shown that—taking into account the thermodynamic efficiency of the cryogenic plant—the 4.2 K Q0 values obtained meet the AC power consumption requirements of state-of-the-art high duty factor accelerators, making this a proof-of-principle demonstration for Nb3Sn cavities in future applications.

Low-temperature field evaporation of Nb3Sn compound

International Nuclear Information System (INIS)

Ksenofontov, V.A.; Kul'ko, V.B.; Kutsenko, P.A.

1986-01-01

Investigation results on field evaporation of superconducting Nb 3 Sn compound wth A15 lattice are presented. Compound evaporation is shown to proceed in two stages. Evaporation field and ionic composition of evaporating material are determined. It is found out that in strong electric fields compound surface represents niobium skeleton, wich does not form regular image. Comparison of ion-microscopic and calculated images formed by low-temperature field evaporation indicates to possibility of sample surface reconstruction after preferable tin evaporation

Thermo-magnetic instabilities in Nb3Sn Superconducting Accelerator Magnets

International Nuclear Information System (INIS)

Bordini, Bernardo; Pisa U.

2006-01-01

The advance of High Energy Physics research using circulating accelerators strongly depends on increasing the magnetic bending field which accelerator magnets provide. To achieve high fields, the most powerful present-day accelerator magnets employ NbTi superconducting technology; however, with the start up of Large Hadron Collider (LHC) in 2007, NbTi magnets will have reached the maximum field allowed by the intrinsic properties of this superconductor. A further increase of the field strength necessarily requires a change in superconductor material; the best candidate is Nb 3 Sn. Several laboratories in the US and Europe are currently working on developing Nb 3 Sn accelerator magnets, and although these magnets have great potential, it is suspected that their performance may be fundamentally limited by conductor thermo-magnetic instabilities: an idea first proposed by the Fermilab High Field Magnet group early in 2003. This thesis presents a study of thermo-magnetic instability in high field Nb 3 Sn accelerator magnets. In this chapter the following topics are described: the role of superconducting magnets in High Energy Physics; the main characteristics of superconductors for accelerator magnets; typical measurements of current capability in superconducting strands; the properties of Nb 3 Sn; a description of the manufacturing process of Nb 3 Sn strands; superconducting cables; a typical layout of superconducting accelerator magnets; the current state of the art of Nb 3 Sn accelerator magnets; the High Field Magnet program at Fermilab; and the scope of the thesis

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

International Nuclear Information System (INIS)

Luhman, T.; Suenaga, M.

1975-01-01

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

Theoretical calculation of performance enhancement in lattice-matched SiGeSn/GeSn p-channel tunneling field-effect transistor with type-II staggered tunneling junction

Science.gov (United States)

Wang, Hongjuan; Han, Genquan; Wang, Yibo; Peng, Yue; Liu, Yan; Zhang, Chunfu; Zhang, Jincheng; Hu, Shengdong; Hao, Yue

2016-04-01

In this work, a lattice-matched SiGeSn/GeSn heterostructure p-channel tunneling field-effect transistor (hetero-PTFET) with a type-II staggered tunneling junction (TJ) is investigated theoretically. Lattice matching and type-II band alignment at the Γ-point is obtained at the SiGeSn/GeSn interface by tuning Sn and Si compositions. A steeper subthreshold swing (SS) and a higher on state current (I ON) are demonstrated in SiGeSn/GeSn hetero-PTFET than in GeSn homo-PTFET. Si0.31Ge0.49Sn0.20/Ge0.88Sn0.12 hetero-PTFET achieves a 2.3-fold higher I ON than Ge0.88Sn0.12 homo-PTFET at V DD of 0.3 V. Hetero-PTFET achieves a more abrupt hole profile and a higher carrier density near TJ than the homo-PTFET, which contributes to the significantly enhanced band-to-band tunneling (BTBT) rate and tunneling current in hetero-PTFET.

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

Science.gov (United States)

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

2017-12-01

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

Magnetic structure of RPdSn (R=Tb, Ho) single crystal compounds under strong magnetic field

International Nuclear Information System (INIS)

Andoh, Y.; Kurisu, M.; Nakamoto, G.; Tsutaoka, T.; Kawano, S.

2003-01-01

Rare earth compounds RTX, where R stands for rare earth elements, T for Ni, Pd or Rh, and X for Sn or Ge, crystallize to a rhombic ε-TiNiSi structure. Only rare earth elements R contribute to magnetic properties since T and X atoms are nonmagnetic. The competition between RKKY indirect interaction and large magnetic anisotropy generates many complicated magnetic phases. At a low temperature phase, complicated magnetisms such as meta-magnetism were observed in magnetization curves with many steps. In previous experiments dealing with RPdSn where R means Tb or Ho, some characteristics of magnetic properties of these compounds were deduced from magnetization measurements and neutron diffraction without external magnetic field. In this report, the change of magnetic scattering of neutron diffraction was studied under external magnetic fields in order to reveal the mechanism of the phase transformations of the compounds. The difference between TbPdSn and HoPdSn compounds was observed in magnetic field dependence of the wave vectors of the magnetic scattering. Two independent wave vectors in magnetic scattering existed in HoPdSn compound. (Y. Kazumata)

Influence of Ta and Ti Doping on the High Field Performance of (Nb, Ta, Ti)3Sn Multifilamentary Wires based on Osprey Bronze with High Tin Content

International Nuclear Information System (INIS)

Abaecherli, V; Uglietti, D; Lezza, P; Seeber, B; Fluekiger, R; Cantoni, M; Buffat, P-A

2006-01-01

Ta and Ti are the most widely used additions for technical Nb 3 Sn multifilamentary superconductors. These elements are known to influence grain growth, grain morphology and chemical composition in the A15 layer, hence the current carrying properties of the wires over a wide magnetic field range. So far only few studies tried to compare systematically Ta and Ti doped and undoped Nb 3 Sn wires in the frame of the same work, down to a nanometric scale. We present an investigation on several multifilamentary (Nb, Ta, Ti) 3 Sn bronze route wires, fabricated at a laboratory scale, with various amounts of additives. The wires consist of fine filaments embedded in a Cu-Sn or Cu-Sn-Ti Osprey bronze with > 15 wt.% Sn and an external Cu stabilization. Microstructural observations are compared with the results of J c and n values measured up to 21 T at 4.2 and 2.2 K, and for longitudinal strains up to 0.5%. Non-Cu J c values up to 300 Amm -2 and n values up to 50 at 17 T and 4.2 K show clearly that wires with Ti addition to the bronze have a better performance with respect to wires with Ti additions to the filaments

Highly Reproducible Sn-Based Hybrid Perovskite Solar Cells with 9% Efficiency

NARCIS (Netherlands)

Shao, Shuyan; Liu, Jian; Portale, Giuseppe; Fang, Hong-Hua; Blake, Graeme R.; ten Brink, Gert H.; Koster, L. Jan Anton; Loi, Maria Antonietta

2018-01-01

The low power conversion efficiency (PCE) of tin-based hybrid perovskite solar cells (HPSCs) is mainly attributed to the high background carrier density due to a high density of intrinsic defects such as Sn vacancies and oxidized species (Sn4+) that characterize Sn-based HPSCs. Herein, this study

Systematic study of hyperfine fields in Rh2 Y Z type Heusler alloys with 119 Sn impurity using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Ramos, S.M.M.

1985-01-01

The magnetic hyperfine fields in the Heusler alloys Rh 2 Mn .98 Ge Sn 02 , Rh 2 Mn Ge .98 Sn .02 , Rh 2 Mn Pb .98 Sn .02 and Rh 2 Mn Sn has been studied by 119 Sn Moessbauer spectroscopy at 293 K, 77 K, 4.2 K and 293 K with applied external magnetic field. The results show that when one compare the magnetic hyperfine fields systematic with the Heusler alloys X 2 Mn Z (X = Co, Ni, Cu, Pd, and Z = s p metal), this systematic is similar to the Co alloys, although can not explained by the currents models for the Heusler alloys. (author)

Measurement of Fast Voltage Transients in High-Performance Nb3Sn Magnets

Energy Technology Data Exchange (ETDEWEB)

Lietzke, A. F.; Sabbi., G. L.; Ferracin, P.; Caspi, S.; Zimmerman, S.; Joseph, J.; Doering, D.; Lizarazo, J.

2008-06-01

The Superconducting Magnet group at Lawrence Berkeley National Laboratory has been developing Nb{sub 3}Sn high-field accelerator magnet technology for the last fifteen years. In order to support the magnet R&D effort, we are developing a diagnostic system that can help identify the causes of performance limiting quenches by recording small flux-changes within the magnet prior to quench-onset. These analysis techniques were applied to the test results from recent Nb{sub 3}Sn magnets. This paper will examine various types of events and their distinguishing characteristics. The present measurement techniques are discussed along with the design of a new data acquisition system that will substantially improve the quality of the recorded signals.

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.

Proof-of-principle demonstration of Nb{sub 3}Sn superconducting radiofrequency cavities for high Q{sub 0} applications

Energy Technology Data Exchange (ETDEWEB)

Posen, S., E-mail: sep93@cornell.edu; Liepe, M.; Hall, D. L. [Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York 14853 (United States)

2015-02-23

Many future particle accelerators require hundreds of superconducting radiofrequency (SRF) cavities operating with high duty factor. The large dynamic heat load of the cavities causes the cryogenic plant to make up a significant part of the overall cost of the facility. This contribution can be reduced by replacing standard niobium cavities with ones coated with a low-dissipation superconductor such as Nb{sub 3}Sn. In this paper, we present results for single cell cavities coated with Nb{sub 3}Sn at Cornell. Five coatings were carried out, showing that at 4.2 K, high Q{sub 0} out to medium fields was reproducible, resulting in an average quench field of 14 MV/m and an average 4.2 K Q{sub 0} at quench of 8 × 10{sup 9}. In each case, the peak surface magnetic field at quench was well above H{sub c1}, showing that it is not a limiting field in these cavities. The coating with the best performance had a quench field of 17 MV/m, exceeding gradient requirements for state-of-the-art high duty factor SRF accelerators. It is also shown that—taking into account the thermodynamic efficiency of the cryogenic plant—the 4.2 K Q{sub 0} values obtained meet the AC power consumption requirements of state-of-the-art high duty factor accelerators, making this a proof-of-principle demonstration for Nb{sub 3}Sn cavities in future applications.

High field superconductor development and understanding project, Final Report

Energy Technology Data Exchange (ETDEWEB)

Larbalestier, David C.; Lee, Peter J.

2009-07-15

Over 25 years the Applied Superconductivity Center at the University of Wisconsin-Madison provided a vital technical resource to the High Energy Physics community covering development in superconducting strand for HEP accelerator magnet development. In particular the work of the group has been to develop the next generation of high field superconductors for high field application. Grad students Mike Naus, Chad Fischer, Arno Godeke and Matt Jewell improved our understanding of the microstructure and microchemistry of Nb3Sn and their impact on the physical and mechanical properties. The success of this work has led to the continued funding of this work at the ASC after it moved to the NHMFL and also to direct funding from BNL for some aspects of Nb3Sn cable evaluation.

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

Science.gov (United States)

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

2017-05-01

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

N-MOSFETs Formed on Solid Phase Epitaxially Grown GeSn Film with Passivation by Oxygen Plasma Featuring High Mobility.

Science.gov (United States)

Fang, Yung-Chin; Chen, Kuen-Yi; Hsieh, Ching-Heng; Su, Chang-Chia; Wu, Yung-Hsien

2015-12-09

Solid phase epitaxially grown GeSn was employed as the platform to assess the eligibility of direct O2 plasma treatment on GeSn surface for passivation of GeSn N-MOSFETs. It has been confirmed that O2 plasma treatment forms a GeSnO(x) film on the surface and the GeSnO(x) topped by in situ Al2O3 constitutes the gate stack of GeSn MOS devices. The capability of the surface passivation was evidenced by the low interface trap density (D(it)) of 1.62 × 10(11) cm(-2) eV(-1), which is primarily due to the formation of Ge-O and Sn-O bonds at the surface by high density/reactivity oxygen radicals that effectively suppress dangling bonds and decrease gap states. The good D(it) not only makes tiny frequency dispersion in the characterization of GeSn MOS capacitors, but results in GeSn N-MOSFETs with outstanding peak electron mobility as high as 518 cm(2)/(V s) which outperforms other devices reported in the literature due to reduced undesirable carrier scattering. In addition, the GeSn N-MOSFETs also exhibit promising characteristics in terms of acceptable subthreshold swing of 156 mV/dec and relatively large I(ON)/I(OFF) ratio more than 4 orders. Moreover, the robust reliability in terms small V(t) variation against high field stress attests the feasibility of using the O2 plasma-treated passivation to advanced GeSn technology.

Constraining Magnetic Field Amplification in SN Shocks Using Radio Observations of SNe 2011fe and 2014J

Science.gov (United States)

Kundu, E.; Lundqvist, P.; Pérez-Torres, M. A.; Herrero-Illana, R.; Alberdi, A.

2017-06-01

We modeled the radio non-detection of two Type Ia supernovae (SNe), SN 2011fe and SN 2014J, considering synchrotron emission from the interaction between SN ejecta and the circumstellar medium. For ejecta whose outer parts have a power-law density structure, we compare synchrotron emission with radio observations. Assuming that 20% of the bulk shock energy is being shared equally between electrons and magnetic fields, we found a very low-density medium around both the SNe. A less tenuous medium with particle density ˜1 cm-3, which could be expected around both SNe, can be estimated when the magnetic field amplification is less than that presumed for energy equipartition. This conclusion also holds if the progenitor of SN 2014J was a rigidly rotating white dwarf (WD) with a main-sequence (MS) or red giant companion. For a He star companion, or a MS for SN 2014J, with 10% and 1% of bulk kinetic energy in magnetic fields, we obtain mass-loss rates of 99% onto the WD, but is less restricted for the latter case. However, if the tenuous medium is due to a recurrent nova, it is difficult from our model to predict synchrotron luminosities. Although the formation channels of SNe 2011fe and 2014J are not clear, the null detection in radio wavelengths could point toward a low amplification efficiency for magnetic fields in SN shocks.

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

CERN Document Server

Lee, P J; Larbalestier, D C

2000-01-01

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

Ceramic insulation for superconducting Nb{sub 3}Sn cables; Isolation ceramique pour cables supraconducteurs en Nb{sub 3}Sn

Energy Technology Data Exchange (ETDEWEB)

Puigsegur, A

2005-01-15

Nb{sub 3}Sn is the best superconductor candidate for the realization of high field magnets (>11 Tesla), its implementation remains delicate because of the great brittleness of material after the heat treatment necessary to the formation of Nb{sub 3}Sn compounds. The conventional insulation for Nb{sub 3}Sn requires to perform, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We have proposed an innovating ceramic insulation deposited directly on the unreacted conducting cable. After the heat treatment of the niobium tin, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. After a rheological study, to characterize the impregnated suspension, we have shown that using this insulation in a coil manufacture process does not affect the electrical properties of the Nb{sub 3}Sn wires. A solenoid of small dimensions was tested with success in high external magnetic fields and has produced a magnetic field of 3.8 T under 740 A. (author)

Field Quality Measurements of LARP Nb$_{3}$Sn Magnet HQ02

CERN Document Server

DiMarco, J; Buehler, M; Chlachidze, G; Orris, D; Sylvester, C; Tartaglia, M; Velev, G; Yu, M; Zlobin, A; Ghosh, A; Schmalzle, J; Wanderer, P; Borgnolutti, F; Cheng, D; Dietderich, D; Felice, H; Godeke, A; Hafalia, R; Joseph, J; Lizarazo, J; Marchevsky, M; Prestemon, S O; Sabbi, G L; Salehi, A,; Wang, X; Ferracin, P; Todesco, E

2014-01-01

Large-aperture, high-field, Nb$_{3}$Sn quadrupoles are being developed by the US LHC accelerator research program (LARP) for the High luminosity upgrade of the Large Hadron Collider (HiLumi-LHC). The first 1 m long, 120 mm aperture prototype, HQ01, was assembled with various sets of coils and tested at LBNL and CERN. Based on these results, several design modifications have been introduced to improve the performance for HQ02, the latest model. From the field quality perspective, the most relevant improvements are a cored cable for reduction of eddy current effects, and more uniform coil components and fabrication processes. This paper reports on the magnetic measurements of HQ02 during recent testing at the Vertical Magnet Test Facility at Fermilab. Results of baseline measurements performed with a new multi-layer circuit board probe are compared with the earlier magnet. An analysis of probe and measurement system performance is also presented.

Migration of Sn and Pb from Solder Ribbon onto Ag Fingers in Field-Aged Silicon Photovoltaic Modules

Directory of Open Access Journals (Sweden)

Wonwook Oh

2015-01-01

Full Text Available We investigated the migration of Sn and Pb onto the Ag fingers of crystalline Si solar cells in photovoltaic modules aged in field for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells. This phenomenon is not observed in a standard acceleration test condition for PV modules. In contrast to the acceleration test conditions, field aging subjects the PV modules to solar irradiation and moisture condensation at the interface between the solar cells and the encapsulant. The solder ribbon releases Sn and Pb via repeated galvanic corrosion and the Sn and Pb precipitate on Ag fingers due to the light-induced plating under solar irradiation.

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.

The first critical field, Hc1perpendicularto, and the penetration depth in dirty superconducting S/N multilayers

International Nuclear Information System (INIS)

Golubov, A.A.; Krasnov, V.M.

1992-01-01

The proximity effect in dirty S/N multilayers is studied theoretically. The structure of the Abrikosov vortex and the first critical field, H c1 perpendicular to , in a perpendicular magnetic field is investigated. Our approach is based on solving Ginzburg-Landau and Usadel equations with boundary conditions applicable to real structures. It was shown that for highly conducting N-layers there exists a positive curvature on H c1 (T) dependences. (orig.)

Volcanic-plutonic connections and metal fertility of highly evolved magma systems: A case study from the Herberton Sn-W-Mo Mineral Field, Queensland, Australia

Science.gov (United States)

Cheng, Yanbo; Spandler, Carl; Chang, Zhaoshan; Clarke, Gavin

2018-03-01

Understanding the connection between the highly evolved intrusive and extrusive systems is essential to explore the evolution of high silicic magma systems, which plays an important role in discussions of planetary differentiation, the growth of continents, crustal evolution, and the formation of highly evolved magma associated Sn-W-Mo mineral systems. To discern differences between "fertile" and "non-fertile" igneous rocks associated with Sn-W-Mo mineralization and reveal the genetic links between coeval intrusive and extrusive rocks, we integrate whole rock geochemistry, geochronology and Hf isotope signatures of igneous zircons from contemporaneous plutonic and volcanic rocks from the world-class Herberton Mineral Field of Queensland, Australia. The 310-300 Ma intrusive rocks and associated intra-plutonic W-Mo mineralization formed from relatively oxidized magmas after moderate degrees of crystal fractionation. The geochemical and isotopic features of the coeval volcanic succession are best reconciled utilizing the widely-accepted volcanic-plutonic connection model, whereby the volcanic rocks represent fractionated derivatives of the intrusive rocks. Older intrusions emplaced at 335-315 Ma formed from relatively low fO2 magmas that fractionated extensively to produce highly evolved granites that host Sn mineralization. Coeval volcanic rocks of this suite are compositionally less evolved than the intrusive rocks, thereby requiring a different model to link these plutonic-volcanic sequences. In this case, we propose that the most fractionated magmas were not lost to volcanism, but instead were effectively retained at the plutonic level, which allowed further localized build-up of volatiles and lithophile metals in the plutonic environment. This disconnection to the volcanism and degassing may be a crucial step for forming granite-hosted Sn mineralization. The transition between these two igneous regimes in Herberton region over a ∼30 m.y. period is attributed to

Nitrogen-Doped Carbon-Encapsulated SnO2@Sn Nanoparticles Uniformly Grafted on Three-Dimensional Graphene-like Networks as Anode for High-Performance Lithium-Ion Batteries.

Science.gov (United States)

Li, Yunyong; Zhang, Haiyan; Chen, Yiming; Shi, Zhicong; Cao, Xiaoguo; Guo, Zaiping; Shen, Pei Kang

2016-01-13

A peculiar nanostructure consisting of nitrogen-doped, carbon-encapsulated (N-C) SnO2@Sn nanoparticles grafted on three-dimensional (3D) graphene-like networks (designated as N-C@SnO2@Sn/3D-GNs) has been fabricated via a low-cost and scalable method, namely an in situ hydrolysis of Sn salts and immobilization of SnO2 nanoparticles on the surface of 3D-GNs, followed by an in situ polymerization of dopamine on the surface of the SnO2/3D-GNs, and finally a carbonization. In the composites, three-layer core-shell N-C@SnO2@Sn nanoparticles were uniformly grafted onto the surfaces of 3D-GNs, which promotes highly efficient insertion/extraction of Li(+). In addition, the outermost N-C layer with graphene-like structure of the N-C@SnO2@Sn nanoparticles can effectively buffer the large volume changes, enhance electronic conductivity, and prevent SnO2/Sn aggregation and pulverization during discharge/charge. The middle SnO2 layer can be changed into active Sn and nano-Li2O during discharge, as described by SnO2 + Li(+) → Sn + Li2O, whereas the thus-formed nano-Li2O can provide a facile environment for the alloying process and facilitate good cycling behavior, so as to further improve the cycling performance of the composite. The inner Sn layer with large theoretical capacity can guarantee high lithium storage in the composite. The 3D-GNs, with high electrical conductivity (1.50 × 10(3) S m(-1)), large surface area (1143 m(2) g(-1)), and high mechanical flexibility, tightly pin the core-shell structure of the N-C@SnO2@Sn nanoparticles and thus lead to remarkably enhanced electrical conductivity and structural integrity of the overall electrode. Consequently, this novel hybrid anode exhibits highly stable capacity of up to 901 mAh g(-1), with ∼89.3% capacity retention after 200 cycles at 0.1 A g(-1) and superior high rate performance, as well as a long lifetime of 500 cycles with 84.0% retention at 1.0 A g(-1). Importantly, this unique hybrid design is expected to be

High-field, high-density tokamak power reactor

International Nuclear Information System (INIS)

Cohn, D.R.; Cook, D.L.; Hay, R.D.; Kaplan, D.; Kreischer, K.; Lidskii, L.M.; Stephany, W.; Williams, J.E.C.; Jassby, D.L.; Okabayashi, M.

1977-11-01

A conceptual design of a compact (R 0 = 6.0 m) high power density (average P/sub f/ = 7.7 MW/m 3 ) tokamak demonstration power reactor has been developed. High magnetic field (B/sub t/ = 7.4 T) and moderate elongation (b/a = 1.6) permit operation at the high density (n(0) approximately 5 x 10 14 cm -3 ) needed for ignition in a relatively small plasma, with a spatially-averaged toroidal beta of only 4%. A unique design for the Nb 3 Sn toroidal-field magnet system reduces the stress in the high-field trunk region, and allows modularization for simpler disassembly. The modest value of toroidal beta permits a simple, modularized plasma-shaping coil system, located inside the TF coil trunk. Heating of the dense central plasma is attained by the use of ripple-assisted injection of 120-keV D 0 beams. The ripple-coil system also affords dynamic control of the plasma temperature during the burn period. A FLIBE-lithium blanket is designed especially for high-power-density operation in a high-field environment, and gives an overall tritium breeding ratio of 1.05 in the slowly pumped lithium

Volume pinning force and upper critical field of irradiated Nb3Sn

International Nuclear Information System (INIS)

Maier, P.; Seibt, E.

1981-01-01

Irradiation by neutrons and ions in A15 superconductors (Nb 3 Sn, V 3 Ga) exerts a stronger influence on the pinning behavior than in nonordered alloys (NbTi). In this work it is shown for deuteron irradiated Nb 3 /Sn wires prepared by the bronze process that the dose curve of the volume pinning force P/sub V/ can be conveniently described by a sum of two terms, due to the grain boundary pinning and to the radiation pinning, respectively. After deduction of the contribution by the radiation-induced pinning centers, good agreement is obtained between the measured P/sub V/ values and those calculated using the upper critical field B/sub c/2 and the transition temperature T/sub c/ on the basis of the irradiation fluence. The use of a theoretical relationship between B/sub c/2 and T/sub c/ is supported by measured values. Application to multifilamentary superconductors with high current carrying capabilities simplifies the calculation of P/sub V/, since the radiation induced volume pinning force can be neglected

Thermal and mechanical effects of quenches on Nb3Sn high field hadron collider magnets

International Nuclear Information System (INIS)

Ryuji, Yamada

2001-01-01

Thermal and its resulting mechanical stress due to quenches inside short and long epoxy impregnated Nb 3 Sn high field magnets are studied with a quench simulation program, Kuench, and ANSYS program. For the protection of a long high field magnet, we have to use heaters to dump the stored energy uniformly inside the magnet, after detection of a spontaneous quench. The time delay of starting a forced quench with heaters, is estimated using ANSYS. Using this information, the thermal distribution in two-dimensional magnet cross section is studied. First a one meter model magnet with a dump resistor is used to estimate the effects and then a 10 meter long magnet is studied. The two-dimensional temperature distributions in the magnet cross sections are recorded every 5 ms, and visually displayed. With this visual animation displays we can understand intuitively the thermal and quench propagation in 2-dimensional field. The quenching cables get heated locally much more than the surrounding material and non-quenching conductor cables. With a one meter magnet with a dump resistor of 30 mOmega, typically only the quench starting cables and its neighbor cables get heated up to 100 K without significant effects from the heaters. With a10 meter magnet, heaters cause the quenches to most of the conductor blocks. The quench initiating cables get up to 250 to 300 K in 100 ms, but the surrounding and wedges are not heated up significantly. This causes the excessive stress in the quenching conductors and in their insulation material locally. The stress and strain in the conductor as well as in the insulation become excessive, and they are studied using the ANSYS stress analysis, using Von Mises criterion. It is concluded that for the one meter magnet with the presented cross section and configuration, the thermal effects due to the quench is tolerable. But we need much more quench study and improvements in the design for the extended ten meter long magnet [1

Dominant effect of high anisotropy in β-Sn grain on electromigration-induced failure mechanism in Sn-3.0Ag-0.5Cu interconnect

Energy Technology Data Exchange (ETDEWEB)

Huang, M.L., E-mail: huang@dlut.edu.cn; Zhao, J.F.; Zhang, Z.J.; Zhao, N.

2016-09-05

The effect of high diffusivity anisotropy in β-Sn grain on electromigration behavior of micro-bumps was clearly demonstrated using Sn-3.0Ag-0.5Cu solder interconnects with only two β-Sn grains. The orientation of β-Sn grain (θ is defined as the angle between the c-axis of β-Sn grain and the electron flow direction) is becoming the most crucial factor to dominate the different electromigration-induced failure modes: 1) the excessive dissolution of the cathode Cu, blocking at the grain boundary and massive precipitation of columnar Cu{sub 6}Sn{sub 5} intermetallic compounds (IMCs) in the small angle θ β-Sn grain occur when electrons flow from a small angle θ β-Sn grain to a large one; 2) void formation and propagation occur at the cathode IMC/solder interface and no Cu{sub 6}Sn{sub 5} IMCs precipitate within the large angle θ β-Sn grain when electrons flow in the opposite direction. The EM-induced failure mechanism of the two β-Sn grain solder interconnects is well explained in viewpoint of atomic diffusion flux in β-Sn. - Highlights: • High anisotropy in β-Sn dominates different electromigration-induced failure mode. • Excessive dissolution of cathode Cu occurs if electrons flow in forward direction. • Voids initiate and propagate at cathode if electrons flow in reverse direction. • Failure modes are well explained in viewpoint of atomic diffusion flux in β-Sn.

Ultrathin Layered SnSe Nanoplates for Low Voltage, High-Rate, and Long-Life Alkali-Ion Batteries.

Science.gov (United States)

Wang, Wei; Li, Peihao; Zheng, Henry; Liu, Qiao; Lv, Fan; Wu, Jiandong; Wang, Hao; Guo, Shaojun

2017-12-01

2D electrode materials with layered structures have shown huge potential in the fields of lithium- and sodium-ion batteries. However, their poor conductivity limits the rate performance and cycle stability of batteries. Herein a new colloid chemistry strategy is reported for making 2D ultrathin layered SnSe nanoplates (SnSe NPs) for achieving more efficient alkali-ion batteries. Due to the effect of weak Van der Waals forces, each semiconductive SnSe nanoplate stacks on top of each other, which can facilitate the ion transfer and accommodate volume expansion during the charge and discharge process. This unique structure as well as the narrow-bandgap semiconductor property of SnSe simultaneously meets the requirements of achieving fast ionic and electronic conductivities for alkali-ion batteries. They exhibit high capacity of 463.6 mAh g -1 at 0.05 A g -1 for Na-ion batteries and 787.9 mAh g -1 at 0.2 A g -1 for Li-ion batteries over 300 cycles, and also high stability for alkali-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Porous SnO2-CuO nanotubes for highly reversible lithium storage

Science.gov (United States)

Cheong, Jun Young; Kim, Chanhoon; Jung, Ji-Won; Yoon, Ki Ro; Kim, Il-Doo

2018-01-01

Facile synthesis of rationally designed structures is critical to realize a high performance electrode for lithium-ion batteries (LIBs). Among different candidates, tin(IV) oxide (SnO2) is one of the most actively researched electrode materials due to its high theoretical capacity (1493 mAh g-1), abundance, inexpensive costs, and environmental friendliness. However, severe capacity decay from the volume expansion and low conductivity of SnO2 have hampered its use as a feasible electrode for LIBs. Rationally designed SnO2-based nanostructures with conductive materials can be an ideal solution to resolve such limitations. In this work, we have successfully fabricated porous SnO2-CuO composite nanotubes (SnO2-CuO p-NTs) by electrospinning and subsequent calcination step. The porous nanotubular structure is expected to mitigate the volume expansion of SnO2, while the as-formed Cu from CuO upon lithiation allows faster electron transport by improving the low conductivity of SnO2. With a synergistic effect of both Sn and Cu-based oxides, SnO2-CuO p-NTs deliver stable cycling performance (91.3% of capacity retention, ∼538 mAh g-1) even after 350 cycles at a current density of 500 mA g-1, along with enhanced rate capabilities compared with SnO2.

Design Studies of Nb3Sn High-Gradient Quadrupole Models for LARP

International Nuclear Information System (INIS)

Andreev, Nikolai; Caspi, Shlomo; Dietderich, Daniel; Ferracin, Paolo; Ghosh, Arup; Kashikhin, Vadim; Lietzke, Al; Novitski, Igor; Zlobin, Alexander; McInturff, Alfred; Sabbi, GianLuca

2007-01-01

Insertion quadrupoles with large aperture and high gradient are required to achieve the luminosity upgrade goal of 10 35 cm -2 s -1 at the Large Hadron Collider (LHC). In 2004, the US Department of Energy established the LHC Accelerator Research Program (LARP) to develop a technology base for the upgrade. Nb 3 Sn conductor is required in order to operate at high field and with sufficient temperature margin. We report here on the conceptual design studies of a series of 1 m long 'High-gradient Quadrupoles' (HQ) that will explore the magnet performance limits in terms of peak fields, forces and stresses. The HQ design is expected to provide coil peak fields of more than 15 T, corresponding to gradients above 300 T/m in a 90 mm bore. Conductor requirements, magnetic, mechanical and quench protection issues for candidate HQ designs will be presented and discussed

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

Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors: Impact of sulfur passivation on gate stack quality

Energy Technology Data Exchange (ETDEWEB)

Lei, Dian; Wang, Wei; Gong, Xiao, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhang, Zheng; Pan, Jisheng [Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

2016-01-14

The effect of room temperature sulfur passivation of the surface of Ge{sub 0.83}Sn{sub 0.17} prior to high-k dielectric (HfO{sub 2}) deposition is investigated. X-ray photoelectron spectroscopy (XPS) was used to examine the chemical bonding at the interface of HfO{sub 2} and Ge{sub 0.83}Sn{sub 0.17}. Sulfur passivation is found to be effective in suppressing the formation of both Ge oxides and Sn oxides. A comparison of XPS results for sulfur-passivated and non-passivated Ge{sub 0.83}Sn{sub 0.17} samples shows that sulfur passivation of the GeSn surface could also suppress the surface segregation of Sn atoms. In addition, sulfur passivation reduces the interface trap density D{sub it} at the high-k dielectric/Ge{sub 0.83}Sn{sub 0.17} interface from the valence band edge to the midgap of Ge{sub 0.83}Sn{sub 0.17}, as compared with a non-passivated control. The impact of the improved D{sub it} is demonstrated in Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs). Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs with sulfur passivation show improved subthreshold swing S, intrinsic transconductance G{sub m,int}, and effective hole mobility μ{sub eff} as compared with the non-passivated control. At a high inversion carrier density N{sub inv} of 1 × 10{sup 13 }cm{sup −2}, sulfur passivation increases μ{sub eff} by 25% in Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs.

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

Improvement of stability of Nb₃ Sn superconductors by introducing high specific heat substances

Energy Technology Data Exchange (ETDEWEB)

Xu, X. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Li, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Zlobin, A. V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Peng, X. [Unlisted, US, OH

2018-01-24

High-J_c Nb₃Sn conductors have low stability against perturbations, which accounts for the slow training rates of high-field Nb₃Sn magnets. While it is known that adding substances with high specific heat (C) into Nb3Sn wires can increase their overall specific heat and thus improve their stability, there has not been a practical method that is compatible with the fabrication of long-length conductors. In this work, we put forward a scheme to introduce such substances to distributed-barrier Nb₃Sn wires, which adds minimum difficulty to the wire manufacturing process. Multifilamentary wires using a mixture of Cu and high-C Gd₂O₃ powders have been successfully fabricated along this line. Measurements showed that addition of Gd₂O₃ had no negative effects on residual resitivity ratio or non-Cu J_c, and that flux jumps were remarkably reduced, and minimum quench energy values at 4.2 K, 14 T were increased by a factor of three, indicating that stability was significantly improved. We also discussed the influences of the positioning of high-C substances and their thermal diffusivity on their effectiveness in reducing the superconductor temperature rise against perturbations. Based on these results, we proposed an optimized conductor architecture to maximize the effectiveness of this approach.

Flow patterns of GaInSn liquid on inclined stainless steel plate under a range of magnetic field

Energy Technology Data Exchange (ETDEWEB)

Yang, Juan-Cheng, E-mail: yangjc@xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi’an Jiaotong University, Xi’an, Shanxi 710049 (China); Qi, Tian-Yu [School of Engineering Sciences, University of Chinese Academy and Sciences, Beijing 100049 (China); Ni, Ming-Jiu, E-mail: mjni@ucas.ac.cn [School of Engineering Sciences, University of Chinese Academy and Sciences, Beijing 100049 (China); Wang, Zeng-Hui [School of Engineering Sciences, University of Chinese Academy and Sciences, Beijing 100049 (China)

2016-11-01

Highlights: • The liquid GaInSn metal flow loop was built to study some fusion related liquid metal MHD phenomenon. • The flow patterns of GaInSn free surface flow with the change of Re number and Ha number were got by lot of experiments. • Some detailed descriptions of these flow patterns were also made, and a solid conclusion which agreed with some previous studies was got. - Abstract: In the present paper, some preliminary experimental studies have been conducted to show the flow pattern of liquid metal flow using visualization method. For the convenience of experiments in lab, Ga{sup 67}In{sup 20.5}Sn{sup 12.5} in liquid state at room temperature is used. A test section made by stainless steel is inserted in a traverse magnetic field with strength (B{sub 0}) varies from 0 to 1.28 T. The inclined angle of stainless steel plate in test section is about 9°. Visualization results obtained by high-speed camera (Phantom M/LC 310) shown that GaInSn liquid flow on inclined stainless steel plate behaved unstable liquid column flow pattern in the low flow rate, while behaved large area spreading flow pattern with small waves on the free surface in the large flow rate. However, in the magnetic field, under the action of electromagnetic force, the flow patterns of GaInSn liquid have some significant changes on the spreading width and surface structure of free surface. Some detailed analyses on these changes have been also showed in the present paper. Plans for future work are also presented.

Ambipolar SnOx thin-film transistors achieved at high sputtering power

Science.gov (United States)

Li, Yunpeng; Yang, Jia; Qu, Yunxiu; Zhang, Jiawei; Zhou, Li; Yang, Zaixing; Lin, Zhaojun; Wang, Qingpu; Song, Aimin; Xin, Qian

2018-04-01

SnO is the only oxide semiconductor to date that has exhibited ambipolar behavior in thin-film transistors (TFTs). In this work, ambipolar behavior was observed in SnOx TFTs fabricated at a high sputtering power of 200 W and post-annealed at 150-250 °C in ambient air. X-ray-diffraction patterns showed polycrystallisation of SnO and Sn in the annealed SnOx films. Scanning-electron-microscopy images revealed that microgrooves appeared after the films were annealed. Clusters subsequently segregated along the microgrooves, and our experiments suggest that they were most likely Sn clusters. Atomic force microscopy images indicate an abrupt increase in film roughness due to the cluster segregations. An important implication of this work is that excess Sn in the film, which has generally been thought to be detrimental to the film quality, may promote the ambipolar conduction when it is segregated from the film to enhance the stoichiometric balance.

SnTe-TiC-C composites as high-performance anodes for Li-ion batteries

Science.gov (United States)

Son, Seung Yeon; Hur, Jaehyun; Kim, Kwang Ho; Son, Hyung Bin; Lee, Seung Geol; Kim, Il Tae

2017-10-01

Intermetallic SnTe composites dispersed in a conductive TiC/C hybrid matrix are synthesized by high-energy ball milling (HEBM). The electrochemical performances of the composites as potential anodes for Li-ion batteries are evaluated. The structural and morphological characteristics of the SnTe-TiC-C composites with various TiC contents are investigated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy, which reveal that SnTe and TiC are uniformly dispersed in a carbon matrix. The electrochemical performance is significantly improved by introducing TiC to the SnTe-C composite; higher TiC contents result in better performances. Among the prepared composites, the SnTe-TiC (30%)-C and SnTe-TiC (40%)-C electrodes exhibit the best electrochemical performance, showing the reversible capacities of, respectively, 652 mAh cm-3 and 588 mAh cm-3 after 400 cycles and high rate capabilities with the capacity retentions of 75.4% for SnTe-TiC (30%)-C and 82.2% for SnTe-TiC (40%)-C at 10 A g-1. Furthermore, the Li storage reaction mechanisms of Te or Sn in the SnTe-TiC-C electrodes are confirmed by ex situ XRD.

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

Background field coils for the High Field Test Facility

International Nuclear Information System (INIS)

Zbasnik, J.P.; Cornish, D.N.; Scanlan, R.M.; Jewell, A.M.; Leber, R.L.; Rosdahl, A.R.; Chaplin, M.R.

1980-01-01

The High Field Test Facility (HFTF), presently under construction at LLNL, is a set of superconducting coils that will be used to test 1-m-o.d. coils of prototype conductors for fusion magnets in fields up to 12 T. The facility consists of two concentric sets of coils; the outer set is a stack of Nb-Ti solenoids, and the inner set is a pair of solenoids made of cryogenically-stabilized, multifilamentary Nb 3 Sn superconductor, developed for use in mirror-fusion magnets. The HFTF system is designed to be parted along the midplane to allow high-field conductors, under development for Tokamak fusion machines, to be inserted and tested. The background field coils were wound pancake-fashion, with cold-welded joints at both the inner and outer diameters. Turn-to-turn insulation was fabricated at LLNL from epoxy-fiberglass strip. The coils were assembled and tested in our 2-m-diam cryostat to verify their operation

Synthesis and Characterization of Highly Sensitive Hydrogen (H2 Sensing Device Based on Ag Doped SnO2 Nanospheres

Directory of Open Access Journals (Sweden)

Zhaorui Lu

2018-03-01

Full Text Available In this paper, pure and Ag-doped SnO2 nanospheres were synthesized by hydrothermal method and characterized via X-ray powder diffraction (XRD, field emission scanning electron microscopy (FESEM, energy dispersive spectroscopy (EDS, and X-ray photoelectron spectra (XPS, respectively. The gas sensing performance of the pure, 1 at.%, 3 at.%, and 5 at.% Ag-doped SnO2 sensing devices toward hydrogen (H2 were systematically evaluated. The results indicated that compared with pure SnO2 nanospheres, Ag-doped SnO2 nanospheres could not only decrease the optimum working temperature but also significantly improve H2 sensing such as higher gas response and faster response-recovery. Among all the samples, the 3 at.% Ag-doped SnO2 showed the highest response 39 to 100 μL/L H2 at 300 °C. Moreover, its gas sensing mechanism was discussed, and the results will provide reference and theoretical guidance for the development of high-performance SnO2-based H2 sensing devices.

High-mobility BaSnO{sub 3} grown by oxide molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

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

2016-01-01

High-mobility perovskite BaSnO{sub 3} films are of significant interest as new wide bandgap semiconductors for power electronics, transparent conductors, and as high mobility channels for epitaxial integration with functional perovskites. Despite promising results for single crystals, high-mobility BaSnO{sub 3} films have been challenging to grow. Here, we demonstrate a modified oxide molecular beam epitaxy (MBE) approach, which supplies pre-oxidized SnO{sub x}. This technique addresses issues in the MBE of ternary stannates related to volatile SnO formation and enables growth of epitaxial, stoichiometric BaSnO{sub 3}. We demonstrate room temperature electron mobilities of 150 cm{sup 2} V{sup −1} s{sup −1} in films grown on PrScO{sub 3}. The results open up a wide range of opportunities for future electronic devices.

Quasi-two-dimensional thermoelectricity in SnSe

Science.gov (United States)

Tayari, V.; Senkovskiy, B. V.; Rybkovskiy, D.; Ehlen, N.; Fedorov, A.; Chen, C.-Y.; Avila, J.; Asensio, M.; Perucchi, A.; di Pietro, P.; Yashina, L.; Fakih, I.; Hemsworth, N.; Petrescu, M.; Gervais, G.; Grüneis, A.; Szkopek, T.

2018-01-01

Stannous selenide is a layered semiconductor that is a polar analog of black phosphorus and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle-resolved photoemission spectroscopy, optical reflection spectroscopy, and magnetotransport measurements reveal a multiple-valley valence-band structure and a quasi-two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250 cm2/V s at T =1.3 K . SnSe is thus found to be a high-quality quasi-two-dimensional semiconductor ideal for thermoelectric applications.

Development of (Nb,Ta3Sn multifilamentary superconductor wire for high current applications

Directory of Open Access Journals (Sweden)

Durval Rodrigues Jr.

2000-10-01

Full Text Available The optimization of the energy generated by a MagnetoHydroDynamic (MHD channel using a superconducting magnet demands the optimization of the magnetic field of the system and of the critical points on the magnet winding. This work must include the development of a high performance superconductor wire suitable for this system. Aiming to the construction of improved performance MHD channel, it was developed a low cost superconductor wire, with the required characteristics. The wire was made using a technology compatible with the assembling steps and heat treatment conditions of the MHD superconducting magnets fabrication. It was used the internal Sn method in Nb-7.5wt%Ta tube to fabricate a 271-filament wire with a diameter of 0.81 mm and a Cu/nonCu ratio of 2.3. The wire was heat treated at 200 °C to diffuse the Sn into the Cu shell, producing bronze, followed by the final reaction at temperatures ranging from 670 °C to 730 °C during 25 to 150 h, to produce (Nb,Ta3Sn. The superconducting wire characterization was made measuring the critical current Ic versus the applied magnetic field in the range of 5 to 20 T, the critical temperature Tc and the residual resistivity ratio (RRR. The wire transported critical currents above those available in commercial superconducting wires. These values of Ic are higher than the expected values for the optimization of the MHD channel.

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

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.

Schottky barrier tuning of the graphene/SnS2 van der Waals heterostructures through electric field

Science.gov (United States)

Zhang, Fang; Li, Wei; Ma, Yaqiang; Dai, Xianqi

2018-03-01

Combining the electronic structures of two-dimensional monolayers in ultrathin hybrid nanocomposites is expected to display new properties beyond their single components. The effects of external electric field (Eext) on the electronic structures of monolayer SnS2 with graphene hybrid heterobilayers are studied by using the first-principle calculations. It is demonstrated that the intrinsic electronic properties of SnS2 and graphene are quite well preserved due to the weak van der Waals (vdW) interactions. We find that the n-type Schottky contacts with the significantly small Schottky barrier are formed at the graphene/SnS2 interface. In the graphene/SnS2 heterostructure, the vertical Eext can control not only the Schottky barriers (n-type and p-type) but also contact types (Schottky contact or Ohmic contact) at the interface. The present study would open a new avenue for application of ultrathin graphene/SnS2 heterostructures in future nano- and optoelectronics.

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.

Ultra-high-field magnets for future hadron colliders

International Nuclear Information System (INIS)

McIntyre, P.M.; Shen, W.

1997-01-01

Several new concepts in magnetic design and coil fabrication are being incorporated into designs for ultra-high field collider magnets: a 16 Tesla block-coil dual dipole, also using Nb 3 Sn cable, featuring simple pancake coil construction and face-loaded prestress geometry; a 330 T/m block-coil quadrupole; and a ∼ 20 Tesla pipe-geometry dual dipole, using A15 or BSCCO tape. Field design and fabrication issues are discussed for each magnet

SnO2Nanowire Arrays and Electrical Properties Synthesized by Fast Heating a Mixture of SnO2and CNTs Waste Soot

Directory of Open Access Journals (Sweden)

Zhou Zhi-Hua

2009-01-01

Full Text Available Abstract SnO2nanowire arrays were synthesized by fast heating a mixture of SnO2and the carbon nanotubes waste soot by high-frequency induction heating. The resultant SnO2nanowires possess diameters from 50 to 100 nm and lengths up to tens of mircrometers. The field-effect transistors based on single SnO2nanowire exhibit that as-synthesized nanowires have better transistor performance in terms of transconductance and on/off ratio. This work demonstrates a simple technique to the growth of nanomaterials for application in future nanoelectronic devices.

Generation of high magnetic fields using superconducting magnets

International Nuclear Information System (INIS)

Kiyoshi, T.; Otsuka, A.; Kosuge, M.; Yuyama, M.; Nagai, H.; Matsumoto, F.

2006-01-01

High-field superconducting magnets have opened new frontiers for several kinds of applications, such as fusion reactors, particle accelerators, and nuclear magnetic resonance (NMR) spectrometers. The present record for the highest field in a fully superconducting state is 23.4 T. It was achieved with a combination of NbTi, Nb 3 Sn, and Bi-2212 conductors in 1999. Since high T c (critical temperature) superconductors (HTS) have sufficiently high critical current density even in excess of 30 T, they are promising for use as high-field superconducting magnets. However, several problems still remain to be resolved for practical applications, and the use of HTS coils will be limited to the inner part of a high-field magnet system in the near future. The required technologies to develop a high-field superconducting magnet with a field of up to 28 T have already been established. Such a magnet is certain to provide information to all leading research areas

Large linear magnetoresistance in topological crystalline insulator Pb_0_._6Sn_0_._4Te

International Nuclear Information System (INIS)

Roychowdhury, Subhajit; Ghara, Somnath; Guin, Satya N.; Sundaresan, A.; Biswas, Kanishka

2016-01-01

Classical magnetoresistance generally follows the quadratic dependence of the magnetic field at lower field and finally saturates when field is larger. Here, we report the large positive non-saturating linear magnetoresistance in topological crystalline insulator, Pb_0_._6Sn_0_._4Te, at different temperatures between 3 K and 300 K in magnetic field up to 9 T. Magnetoresistance value as high as ∼200% was achieved at 3 K at magnetic field of 9 T. Linear magnetoresistance observed in Pb_0_._6Sn_0_._4Te is mainly governed by the spatial fluctuation carrier mobility due to distortions in the current paths in inhomogeneous conductor. - Graphical abstract: Large non-saturating linear magnetoresistance has been evidenced in topological crystalline insulator, Pb_0_._6Sn_0_._4Te, at different temperatures between 3 K and 300 K in magnetic field up to 9 T. - Highlights: • Large non-saturating linear magnetoresistance was achieved in the topological crystalline insulator, Pb_0_._6Sn_0_._4Te. • Highest magnetoresistance value as high as ~200% was achieved at 3 K at magnetic field of 9 T. • Linear magnetoresistance in Pb_0_._6Sn_0_._4Te is mainly governed by the spatial fluctuation of the carrier mobility.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-02-23

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

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.

Studies on advanced superconductors for fusion device. Pt. 1. Present status of Nb3Sn conductors

International Nuclear Information System (INIS)

Tachikawa, Kyoji; Yamamoto, Junya

1996-03-01

Nb 3 Sn conductors have been developed with great expectation as an advanced high-field superconductor to be used in fusion devices of next generation. Furthermore, Nb 3 Sn conductors are being developed for NMR magnet and superconducting generator as well as for cryogen-free superconducting magnet. A variety of fabrication procedures, such as bronze process, internal tin process and Nb tube method, have been developed based on the diffusion reaction. Recently, Nb 3 Sn conductors with ultra-thin filaments have been fabricated for AC use. Both high-field and AC performances of Nb 3 Sn conductors have been significantly improved by alloying addition. The Ti-doped Nb 3 Sn conductor has generated 21.5T at 1.8K operation. This report summarizes manufacturing procedures, superconducting performances and applications of Nb 3 Sn conductors fabricated through different processes in different countries. More detailed subjects included in this report are high-field properties, AC properties, conductors for fusion with large current capacities, stress-strain effect and irradiation effect as well as standardization of critical current measurement method regarding to Nb 3 Sn conductors. Comprehensive grasp on the present status of Nb 3 Sn conductors provided by this report will act as a useful data base for the future planning of fusion devices. (author). 172 refs

3D Flower-Like Hierarchitectures Constructed by SnS/SnS2 Heterostructure Nanosheets for High-Performance Anode Material in Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Zhiguo Wu

2015-01-01

Full Text Available Sn chalcogenides, including SnS, Sn2S3, and SnS2, have been extensively studied as anode materials for lithium batteries. In order to obtain one kind of high capacity, long cycle life lithium batteries anode materials, three-dimensional (3D flower-like hierarchitectures constructed by SnS/SnS2 heterostructure nanosheets with thickness of ~20 nm have been synthesized via a simple one-pot solvothermal method. The obtained samples exhibit excellent electrochemical performance as anode for Li-ion batteries (LIBs, which deliver a first discharge capacity of 1277 mAhg−1 and remain a reversible capacity up to 500 mAhg−1 after 50 cycles at a current of 100 mAg−1.

Flower-like SnO2/graphene composite for high-capacity lithium storage

International Nuclear Information System (INIS)

Liu Hongdong; Huang Jiamu; Li Xinlu; Liu Jia; Zhang Yuxin; Du Kun

2012-01-01

Flower-like SnO 2 /graphene composite is synthesized by a simple hydrothermal method for high-capacity lithium storage. The as-prepared products are characterized by XRD, FTIR, FESEM, TGA and Nitrogen adsorption/desorption. The electrochemical performance of the flower-like SnO 2 /graphene composite is measured by cyclic voltammetry and galvanostatic charge/discharge cycling. The results show that the flower-like SnO 2 nanorod clusters are 800 nm in size and homogeneously adhere on graphene sheets. The flower-like SnO 2 /graphene composite displays superior Li-battery performance with large reversible capacity, excellent cyclic performance and good rate capability.

Conductive framework supported high rate performance of SnO2 hollow nanofibers for lithium battery anodes

International Nuclear Information System (INIS)

Pham-Cong, De; Kim, Ji Yoon; Park, Jung Soo; Kim, Jae Hyun; Kim, Jong-Pil; Jeong, Euh-Duck; Kim, Jinwoo; Jeong, Se-Young; Cho, Chae-Ryong

2015-01-01

We synthesized an electrospun SnO 2 hollow nanofibers (SnO 2 hNFs) coated with carbon and wrapped with graphene oxide layer by simple hydrothermal and electrostatic force method, respectively. Thin carbon layer as electrolyte blocking layer was formed on the SnO 2 hNFs by using glucose as a carbon source (SnO 2 @C hNFs). Also, layers of graphene oxide are wrapped on SnO 2 @C hNFs by the electrostatic interaction force (SnO 2 @C@G hNFs). At high C rate, the average capacity of the SnO 2 @C@G hNFs still kept high capacity comparing with the SnO 2 hNFs and SnO 2 @C hNFs and then increased above 250% at 3 C. It also exhibits a greatly enhanced synergic effect with an extremely high lithium storage capability up to 1,600 mA h g −1 and kept 900 mA h g −1 after 50 cycles benefiting from the advanced structural features

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...

Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

OpenAIRE

R. Nurzulaikha; H.N. Lim; I. Harrison; S.S. Lim; A. Pandikumar; N.M. Huang; S.P. Lim; G.S.H. Thien; N. Yusoff; I. Ibrahim

2015-01-01

A graphene-tin oxide (G-SnO2) nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). A homogeneous deposition of SnO2 nanoparticles with an average partic...

Electronic characteristics of p-type transparent SnO monolayer with high carrier mobility

International Nuclear Information System (INIS)

Du, Juan; Xia, Congxin; Liu, Yaming; Li, Xueping; Peng, Yuting; Wei, Shuyi

2017-01-01

Graphical abstract: SnO monolayer is a p-type transparent semiconducting oxide with high hole mobility (∼641 cm 2 V −1 s −1 ), which is much higher than that of MoS 2 monolayer, which indicate that it can be a promising candidate for high-performance nanoelectronic devices. Display Omitted - Highlights: • SnO monolayer is a p-type transparent semiconducting oxide. • The transparent properties can be still maintained under the strain 8%. • It has a high hole mobility (∼641 cm 2 V −1 s −1 ), which is higher than that of MoS 2 monolayer. - Abstract: More recently, two-dimensional (2D) SnO nanosheets are attaching great attention due to its excellent carrier mobility and transparent characteristics. Here, the stability, electronic structures and carrier mobility of SnO monolayer are investigated by using first-principles calculations. The calculations of the phonon dispersion spectra indicate that SnO monolayer is dynamically stable. Moreover, the band gap values are decreased from 3.93 eV to 2.75 eV when the tensile strain is applied from 0% to 12%. Interestingly, SnO monolayer is a p-type transparent semiconducting oxide with hole mobility of 641 cm 2 V −1 s −1 , which is much higher than that of MoS 2 monolayer. These findings make SnO monolayer becomes a promising 2D material for applications in nanoelectronic devices.

Influence of two-stage annealing treatment on critical current of bronze-processed multifilamentary Nb/sub 3/Sn superconducting materials

International Nuclear Information System (INIS)

Ochiai, S.; Osamura, K.; Ryoji, M.

1987-01-01

The influence of changes of volume fraction of Nb/sub 3/Sn, grain size and upper critical magnetic field due to two-stage annealing treatment (low temperature annealing to form fine grains + high temperature annealing to raise upper critical magnetic field) on overall critical current and critical current density were studied at magnetic field of 3-15 T. When annealing temperature was low (773-923 K) and the volume fraction of Nb/sub 3/Sn was low in first stage annealing, second stage annealing could raise the overall critical current over the range of the applied magnetic field due to increase in upper critical magnetic field H/sub c2/ and volume fraction of Nb/sub 3/Sn accompanying with reduction in Sn concentration in the bronze matrix, which played a role to reduce residual strain in Nb/sub 3/Sn, leading to high H/sub c2/ although the loss in pinning force arose from the coarsening of the grains. When the annealing temperature was high (973 K) and the Nb/sub 3/Sn was formed until the Sn was consumed in the first stage, second stage annealing could not raise the critical current due to increase in grain size and no effective increase in H/sub c2/. The critical current density at low magnetic fields below several Teslas was reduced by the second stage annealing due to increase in grain size but that at high fields was raised due to increase in high H/sub c2/. The reverse two-stage annealing treatment (high temperature annealing in the first stage+low temperature annealing in the second stage) reduced the H/sub c2/ slightly with increasing second stage annealing temperature and time. The critical current density at low magnetic fields was determined mainly by the grain size and that at high fields was determined by the combination of the upper critical field and grain size

Electric field gradient studies in SnSe

Energy Technology Data Exchange (ETDEWEB)

Pal, G. [IUC, DAE Facilities (India); Sebastian, K.C. [M.S. University, Physics Department (India); Chintalapudi, S.N. [IUC, DAE Facilities (India); Somayajulu, D.R.S. [M.S. University, Physics Department (India)

1999-09-15

The EFG in IV-VI compound semiconductor SnSe was studied using two hyperfine interaction techniques, namely, TDPAC and Moessbauer spectroscopy. The EFG in this material increases sharply up to 300 K and thereafter at higher temperatures it gets saturated. However, the conductivity increases steadily at all the temperatures. The conductivity curve has two slopes. The first portion is due to the population of shallow Cd acceptor levels. Thus, in SnSe also the variation of the EFG with temperature is complex, as in other medium-gap semiconductors.

Electric field gradient studies in SnSe

International Nuclear Information System (INIS)

Pal, G.; Sebastian, K.C.; Chintalapudi, S.N.; Somayajulu, D.R.S.

1999-01-01

The EFG in IV-VI compound semiconductor SnSe was studied using two hyperfine interaction techniques, namely, TDPAC and Moessbauer spectroscopy. The EFG in this material increases sharply up to 300 K and thereafter at higher temperatures it gets saturated. However, the conductivity increases steadily at all the temperatures. The conductivity curve has two slopes. The first portion is due to the population of shallow Cd acceptor levels. Thus, in SnSe also the variation of the EFG with temperature is complex, as in other medium-gap semiconductors

Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light.

Science.gov (United States)

Shown, Indrajit; Samireddi, Satyanarayana; Chang, Yu-Chung; Putikam, Raghunath; Chang, Po-Han; Sabbah, Amr; Fu, Fang-Yu; Chen, Wei-Fu; Wu, Chih-I; Yu, Tsyr-Yan; Chung, Po-Wen; Lin, M C; Chen, Li-Chyong; Chen, Kuei-Hsien

2018-01-12

Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS 2 (SnS 2 -C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO 2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS 2 lattice, resulting in different photophysical properties as compared with undoped SnS 2 . This SnS 2 -C photocatalyst significantly enhances the CO 2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS 2 -C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO 2 reduction under visible light, where the in situ carbon-doped SnS 2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.

Moderation of the 119mSn isomer radioactive decay

International Nuclear Information System (INIS)

Godovikov, S.K.

1999-01-01

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

Electronic characteristics of p-type transparent SnO monolayer with high carrier mobility

Energy Technology Data Exchange (ETDEWEB)

Du, Juan [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Xia, Congxin, E-mail: xiacongxin@htu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Liu, Yaming [Henan Institute of Science and Technology, Xinxiang 453003 (China); Li, Xueping [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Peng, Yuting [Department of Physics, University of Texas at Arlington, TX 76019 (United States); Wei, Shuyi [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China)

2017-04-15

Graphical abstract: SnO monolayer is a p-type transparent semiconducting oxide with high hole mobility (∼641 cm{sup 2} V{sup −1} s{sup −1}), which is much higher than that of MoS{sub 2} monolayer, which indicate that it can be a promising candidate for high-performance nanoelectronic devices. Display Omitted - Highlights: • SnO monolayer is a p-type transparent semiconducting oxide. • The transparent properties can be still maintained under the strain 8%. • It has a high hole mobility (∼641 cm{sup 2} V{sup −1} s{sup −1}), which is higher than that of MoS{sub 2} monolayer. - Abstract: More recently, two-dimensional (2D) SnO nanosheets are attaching great attention due to its excellent carrier mobility and transparent characteristics. Here, the stability, electronic structures and carrier mobility of SnO monolayer are investigated by using first-principles calculations. The calculations of the phonon dispersion spectra indicate that SnO monolayer is dynamically stable. Moreover, the band gap values are decreased from 3.93 eV to 2.75 eV when the tensile strain is applied from 0% to 12%. Interestingly, SnO monolayer is a p-type transparent semiconducting oxide with hole mobility of 641 cm{sup 2} V{sup −1} s{sup −1}, which is much higher than that of MoS{sub 2} monolayer. These findings make SnO monolayer becomes a promising 2D material for applications in nanoelectronic devices.

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.

Highly Sensitive and Selective Hydrogen Gas Sensor Using the Mesoporous SnO2 Modified Layers

Directory of Open Access Journals (Sweden)

Niuzi Xue

2017-10-01

Full Text Available It is important to improve the sensitivities and selectivities of metal oxide semiconductor (MOS gas sensors when they are used to monitor the state of hydrogen in aerospace industry and electronic field. In this paper, the ordered mesoporous SnO2 (m-SnO2 powders were prepared by sol-gel method, and the morphology and structure were characterized by X-ray diffraction analysis (XRD, transmission electron microscope (TEM and Brunauer–Emmett–Teller (BET. The gas sensors were fabricated using m-SnO2 as the modified layers on the surface of commercial SnO2 (c-SnO2 by screen printing technology, and tested for gas sensing towards ethanol, benzene and hydrogen with operating temperatures ranging from 200 °C to 400 °C. Higher sensitivity was achieved by using the modified m-SnO2 layers on the c-SnO2 gas sensor, and it was found that the S(c/m2 sensor exhibited the highest response (Ra/Rg = 22.2 to 1000 ppm hydrogen at 400 °C. In this paper, the mechanism of the sensitivity and selectivity improvement of the gas sensors is also discussed.

Porous carbon-free SnSb anodes for high-performance Na-ion batteries

Science.gov (United States)

Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

2018-05-01

A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

Highly sensitive SnO2 sensor via reactive laser-induced transfer

Science.gov (United States)

Palla Papavlu, Alexandra; Mattle, Thomas; Temmel, Sandra; Lehmann, Ulrike; Hintennach, Andreas; Grisel, Alain; Wokaun, Alexander; Lippert, Thomas

2016-04-01

Gas sensors based on tin oxide (SnO2) and palladium doped SnO2 (Pd:SnO2) active materials are fabricated by a laser printing method, i.e. reactive laser-induced forward transfer (rLIFT). Thin films from tin based metal-complex precursors are prepared by spin coating and then laser transferred with high resolution onto sensor structures. The devices fabricated by rLIFT exhibit low ppm sensitivity towards ethanol and methane as well as good stability with respect to air, moisture, and time. Promising results are obtained by applying rLIFT to transfer metal-complex precursors onto uncoated commercial gas sensors. We could show that rLIFT onto commercial sensors is possible if the sensor structures are reinforced prior to printing. The rLIFT fabricated sensors show up to 4 times higher sensitivities then the commercial sensors (with inkjet printed SnO2). In addition, the selectivity towards CH4 of the Pd:SnO2 sensors is significantly enhanced compared to the pure SnO2 sensors. Our results indicate that the reactive laser transfer technique applied here represents an important technical step for the realization of improved gas detection systems with wide-ranging applications in environmental and health monitoring control.

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

African Journals Online (AJOL)

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

Multi-yolk-shell SnO2/Co3Sn2@C Nanocubes with High Initial Coulombic Efficiency and Oxygen Reutilization for Lithium Storage.

Science.gov (United States)

Su, Liwei; Xu, Yawei; Xie, Jian; Wang, Lianbang; Wang, Yuanhao

2016-12-28

The challenging problems of SnO 2 anode material for lithium ion batteries are the poor electronic conductivity and the low oxygen reutilization due to the irreversibility of Li 2 O generated in the initial discharge leading to a theoretical initial Coulombic efficiency (ICE) of only 52.4%. Different from these strategies, this work proposes a novel strategy to level up the oxygen reutilization in SnO 2 by introducing Co 3 Sn 2 nanoalloys which can release Co atoms to reversibly react with Li 2 O instead. According to this protocol, multi-yolk-shell SnO 2 /Co 3 Sn 2 @C nanocubes are designed and successfully prepared using hollow CoSn(OH) 6 nanocubes as precursors followed a hydrothermal carbon coating and calcination treatment. The unique multi-yolk-shell nanostructure offers adequate breathing space for the volumetric deformation during long-term cycling. Moreover, the removal of Li 2 O allows a high electronic conductivity and resultant rate performance. As a result, the efficient reutilization of oxygen enables a high ICE of 71.7% and a reversible capacity of 1003 mA h g -1 after 200 cycles at 100 mA g -1 . Cyclic voltammetry, cycling performance at different voltage windows, and X-ray photoelectron spectroscopy confirm the proposed mechanism. This strategy employing oxygen-poor metals or alloys provides a novel approach to enhance the oxygen reutilization in SnO 2 for higher reversibility.

Structural and optical characterization of p-type highly Fe-doped SnO2 thin films and tunneling transport on SnO2:Fe/p-Si heterojunction

Science.gov (United States)

Ben Haj Othmen, Walid; Ben Hamed, Zied; Sieber, Brigitte; Addad, Ahmed; Elhouichet, Habib; Boukherroub, Rabah

2018-03-01

Nanocrystalline highly Fe-doped SnO2 thin films were prepared using a new simple sol-gel method with iron amounts of 5, 10, 15 and 20%. The obtained gel offers a long durability and high quality allowing to reach a sub-5 nm nanocrystalline size with a good crystallinity. The films were structurally characterized through X-ray diffraction (XRD) that confirms the formation of rutile SnO2. High Resolution Transmission Electron Microscopy (HRTEM) images reveals the good crystallinity of the nanoparticles. Raman spectroscopy shows that the SnO2 rutile structure is maintained even for high iron concentration. The variation of the PL intensity with Fe concentration reveals that iron influences the distribution of oxygen vacancies in tin oxide. The optical transmittance results indicate a redshift of the SnO2 band gap when iron concentration increases. The above optical results lead us to assume the presence of a compensation phenomenon between oxygen vacancies and introduced holes following Fe doping. From current-voltage measurements, an inversion of the conduction type from n to p is strongly predicted to follow the iron addition. Electrical characterizations of SnO2:Fe/p-Si and SnO2:Fe/n-Si heterojunctions seem to be in accordance with this deduction. The quantum tunneling mechanism is expected to be important at high Fe doping level, which was confirmed by current-voltage measurements at different temperatures. Both optical and electrical properties of the elaborated films present a particularity for the same iron concentration and adopt similar tendencies with Fe amount, which strongly correlate the experimental observations. In order to evaluate the applicability of the elaborated films, we proceed to the fabrication of the SnO2:Fe/SnO2 homojunction for which we note a good rectifying behavior.

P-type SnO thin films and SnO/ZnO heterostructures for all-oxide electronic and optoelectronic device applications

Energy Technology Data Exchange (ETDEWEB)

Saji, Kachirayil J. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Govt. Victoria College, University of Calicut, Palakkad 678 001 (India); Venkata Subbaiah, Y.P. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Yogi Vemana University, Kadapa, Andhra Pradesh 516003 (India); Tian, Kun [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

2016-04-30

Tin monoxide (SnO) is considered as one of the most important p-type oxides available to date. Thin films of SnO have been reported to possess both an indirect bandgap (~ 0.7 eV) and a direct bandgap (~ 2.8 eV) with quite high hole mobility (~ 7 cm{sup 2}/Vs) values. Moreover, the hole density in these films can be tuned from 10{sup 15}–10{sup 19} cm{sup −3} just by controlling the thin film deposition parameters. Because of the above attributes, SnO thin films offer great potential for fabricating modern electronic and optoelectronic devices. In this article, we are reviewing the most recent developments in this field and also presenting some of our own results on SnO thin films grown by pulsed laser deposition technique. We have also proposed a p–n heterostructure comprising of p-type SnO and n-type ZnO which can pave way for realizing next-generation, all-oxide transparent electronic devices. - Highlights: • We reviewed recent developments on p-type SnO thin film research. • Discussed the optical and electrical properties of SnO thin films • Bipolar conduction in SnO is discussed. • Optoelectronic properties of SnO–ZnO composite system are discussed. • Proposed SnO–ZnO heterojunction band structure.

Scalable preparation of porous micron-SnO2/C composites as high performance anode material for lithium ion battery

Science.gov (United States)

Wang, Ming-Shan; Lei, Ming; Wang, Zhi-Qiang; Zhao, Xing; Xu, Jun; Yang, Wei; Huang, Yun; Li, Xing

2016-03-01

Nano tin dioxide-carbon (SnO2/C) composites prepared by various carbon materials, such as carbon nanotubes, porous carbon, and graphene, have attracted extensive attention in wide fields. However, undesirable concerns of nanoparticles, including in higher surface area, low tap density, and self-agglomeration, greatly restricted their large-scale practical applications. In this study, novel porous micron-SnO2/C (p-SnO2/C) composites are scalable prepared by a simple hydrothermal approach using glucose as a carbon source and Pluronic F127 as a pore forming agent/soft template. The SnO2 nanoparticles were homogeneously dispersed in micron carbon spheres by assembly with F127/glucose. The continuous three-dimensional porous carbon networks have effectively provided strain relaxation for SnO2 volume expansion/shrinkage during lithium insertion/extraction. In addition, the carbon matrix could largely minimize the direct exposure of SnO2 to the electrolyte, thus ensure formation of stable solid electrolyte interface films. Moreover, the porous structure could also create efficient channels for the fast transport of lithium ions. As a consequence, the p-SnO2/C composites exhibit stable cycle performance, such as a high capacity retention of over 96% for 100 cycles at a current density of 200 mA g-1 and a long cycle life up to 800 times at a higher current density of 1000 mA g-1.

Synthesis of bulk nanocrystalline Pb-Sn-Te alloy under high pressure

International Nuclear Information System (INIS)

Zhu, P W; Chen, L X; Jia, X; Ma, H A; Ren, G Z; Guo, W L; Liu, H J; Zou, G T

2002-01-01

Pb-Sn-Te bulk nanocrystalline (NC) materials are prepared successfully by quenching melts under high pressure. The mean particle size is about 100 nm and the crystal structure is NaCl type. The mechanism of formation of the bulk NC alloy is explained: there is an increasing of the nucleation rate and a decrease in the growth rate of nuclei with increase of pressure during the solidification processes. The thermoelectric properties of Pb-Sn-Te bulk NC alloy are enhanced. This method is promising for producing thermoelectric materials with improved high-energy conversion efficiency

High field Nb3Sn Axicell insert coils for the Mirror Fusion Test Facility-B (MFTF-B) axicell configuration. Final report

International Nuclear Information System (INIS)

Baldi, R.W.; Tatro, R.E.; Scanlan, R.M.

1984-03-01

Two 12-tesla superconducting insert coils are being designed by General Dynamics Convair Division for the axicell regions of MFTF-B for Lawrence Livermore National Laboratory. A major challenge of this project is to ensure that combined fabrication and operational strains induced in the conductor are within stringent limitations of the relatively brittle Nb 3 Sn superconductor filaments. These coils are located in the axicell region of MFTF-B. They have a clear-bore diameter of 36.195cm (14.25 inches) and consist of 27 double pancakes (i.e., 54 pancakes per coil) would on an electrically insulated 304LN stainless steel/bobbin helium vessel. Each pancake has 57 turns separated by G-10CR insulation. The complete winding bundle has 4.6 million ampere-turns and uniform current density of 2007 A/cm 2 . In conjunction with the other magnets in the system, they produce a 12-tesla central field and a 12.52-tesla peak field. A multifilamentary Nb 3 Sn conductor was selected to meet these requirements. The conductor consists of a monolithic insert soldered into a copper stabilizer. Sufficient cross-sectional area and work-hardening of the copper stabilizer has been provided for the conductor to self-react the electromagnetic Lorentz force induced hoop stresses with normal operational tensile strains less than 0.07 percent

Nb3Sn accelerator magnet development around the world

Energy Technology Data Exchange (ETDEWEB)

Michael J. Lamm

2003-06-23

During the past 30 years superconducting magnet systems have enabled accelerators to achieve energies and luminosities that would have been impractical if not impossible with resistive magnets. By far, NbTi has been the preferred conductor for this application because of its ductility and insensitivity of Jc to mechanical strain. This is despite the fact that Nb{sub 3}Sn has a more favorable Jc vs. B dependence and can operate at much higher temperatures. Unfortunately, NbTi conductor is reaching the limit of it usefulness for high field applications. Despite incremental increases in Jc and operation at superfluid temperatures, magnets are limited to approximately a 10 T field. Improvements in conductor performance combined with future requirements for accelerator magnets to have bore fields greater than 10 T or operate in areas of large beam-induced heat loads now make Nb{sub 3}Sn look attractive. Thus, laboratories in several countries are actively engaged in programs to develop Nb{sub 3}Sn accelerator magnets for future accelerator applications. A summary of this important research activity is presented along with a brief history of Nb{sub 3}Sn accelerator magnet development and a discussion of requirements for future accelerator magnets.

PERSISTENT CURRENT EFFECT IN 15-16 T NB3SN ACCELERATOR DIPOLES AND ITS CORRECTION

Energy Technology Data Exchange (ETDEWEB)

Kashikhin, V. V. [Fermilab; Zlobin, A. V. [Fermilab

2016-11-08

Nb3Sn magnets with operating fields of 15-16 T are considered for the LHC Energy Doubler and a future Very High Energy pp Collider. Due to large coil volume, high critical current density and large superconducting (SC) filament size the persistent current effect is very large in Nb3Sn dipoles al low fields. This paper presents the results of analysis of the persistent current effect in the 15 T Nb3Sn dipole demonstrator being developed at FNAL, and describes different possibilities of its correction including passive SC wires, iron shims and coil geometry.

High blocking temperature in SnO{sub 2} based super-paramagnetic diluted magnetic semiconductor

Energy Technology Data Exchange (ETDEWEB)

Mounkachi, O., E-mail: o.mounkachi@mascir.com [Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat (Morocco); Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France); Salmani, E. [LMPHE, associé au CNRST (URAC 12), Faculté des Sciences, Université Mohammed V-Agdal, Rabat (Morocco); El Moussaoui, H. [Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat (Morocco); Masrour, R. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, Safi (Morocco); Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France); Hamedoun, M. [Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat (Morocco); Ez-Zahraouy, H. [LMPHE, associé au CNRST (URAC 12), Faculté des Sciences, Université Mohammed V-Agdal, Rabat (Morocco); Hlil, E.K. [Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France); Benyoussef, A. [Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat (Morocco); LMPHE, associé au CNRST (URAC 12), Faculté des Sciences, Université Mohammed V-Agdal, Rabat (Morocco)

2014-11-25

Highlights: • Simple doping, (Sn,Fe)O{sub 2} exhibits a soft ferromagnetism at low temperature. • High blocking temperature was observed for Cu doped (Sn,Fe)O{sub 2} nanocrystalline. • Experimental results are confirmed by ab initio calculations. - Abstract: (Fe,Cu)-doped SnO{sub 2} nanocrystals was synthesized using the co-precipitation method. Magnetic Properties Measurement System (MPMS) revealed that for simple doping, Fe-doped SnO{sub 2} soft ferromagnetism at low temperature appears, while the ferromagnetic phase is stable at temperature higher than room temperature for Cu co-doping element. The ferromagnetism is significantly enhanced by the Cu addition to Fe-doped SnO{sub 2}, according to the ZFC and FC magnetizations and the hysteresis loops. The evidences for the existence of superparamagnetism are characterized and high blocking temperature super-paramagnetism in (Fe,Cu)-doped SnO{sub 2} nanocrystals was observed. Based on first-principles calculations, we have investigated electronic structures and magnetic properties of Fe-doped SnO{sub 2} and (Fe,Cu)-doped SnO{sub 2} with and without defect with LDA and LDA-SIC approximations. The results suggest that the oxygen vacancies (V{sub O}) play a critical role in the activation of ferromagnetism in Fe doped SnO{sub 2}. For (Fe,Cu)-doped SnO{sub 2} the results exhibit that Cu strongly influences on the magnetic properties of these doped systems which are in good agreement with the experimental observations. Electronic structure show that the presence of Cu promote the ferromagnetic bound magnetic polaron interaction through the carriers introduce by d (Cu)

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

International Nuclear Information System (INIS)

Zhang, Chaowu

2007-07-01

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

Graphene-SnO2 composites for highly efficient photocatalytic degradation of methylene blue under sunlight.

Science.gov (United States)

Seema, Humaira; Christian Kemp, K; Chandra, Vimlesh; Kim, Kwang S

2012-09-07

Graphene sheets decorated with SnO(2) nanoparticles (RGO-SnO(2)) were prepared via a redox reaction between graphene oxide (GO) and SnCl(2). Graphene oxide (GO) was reduced to graphene (RGO) and Sn(2+) was oxidized to SnO(2) during the redox reaction, leading to a homogeneous distribution of SnO(2) nanoparticles on RGO sheets. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show uniform distribution of the nanoparticles on the RGO surface and high-resolution transmission electron microscopy (HRTEM) shows an average particle size of 3-5 nm. The RGO-SnO(2) composite showed an enhanced photocatalytic degradation activity for the organic dye methylene blue under sunlight compared to bare SnO(2) nanoparticles. This result leads us to believe that the RGO-SnO(2) composite could be used in catalytic photodegradation of other organic dyes.

A review and prospects for Nb3Sn superconductor development

Science.gov (United States)

Xu, Xingchen

2017-09-01

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

SnO2 nanoparticles anchored on vertically aligned graphene with a high rate, high capacity, and long life for lithium storage

International Nuclear Information System (INIS)

Li, Na; Sonsg, Huawei; Cui, Hao; Wang, Chengxin

2014-01-01

As a high-theoretical-capacity (782 mA hg-1), low-cost and low-toxicity material, SnO2 has attracted intense interest for use as an anode electrode for lithium-ion batteries (LIBs). Despite intensive study, the practical use of SnO2-based anodes is hindered by their poor capacity retention and low rate capacity resulting from their large specific-volume changes and kinetic limitations in ion/electron transfer during the lithium ion insertion/extraction process. Improving the performance of SnO2-based electrodes has become one of the most popular scientific and industrial efforts. Herein, we present a type of SnO2-graphene composite anode in which SnO2 nanoparticles are uniformly anchored on both sides of vertically aligned graphene nanosheets (SnO2-VAGN-SnO2). The VAGNs sandwiched by the nanoparticles can supply rapid ion and electron transport pathways for Li+ and e-. Such integrated electrodes exhibit high specific capacity and excellent cycling stability, even at high current densities. The cells can cycle more than 5,000 times and retain a reversible capacity of 210 mA h g-1 at 9 A g-1. A high current density of up to 20 A g-1 is achieved, and the power and energy density can reach 1576.75 W kg-1 and 110.14 Wh kg-1, respectively. These performances indicate that the composite could offer the advantages of both LIBs (high energy density) and supercapacitors (high power density)

Exploring the limits of a very large Nb3Sn conductor: the 80 kA conductor of the ITER toroidal field model coil

International Nuclear Information System (INIS)

Duchateau, J.L.; Ciazynski, D.; Guerber, O.; Park, S.H.; Zani, L.

2003-01-01

In Phase II experiment of the International Thermonuclear Experimental Reactor (ITER) Toroidal Field Model Coil (TFMC) the operation limits of its 80 kA Nb 3 Sn conductor were explored. To increase the magnetic field on the conductor, the TFMC was tested in presence of another large coil: the EURATOM-LCT coil. Under these conditions the maximum field reached on the conductor, was around 10 tesla. This exploration has been performed at constant current, by progressively increasing the coil temperature and monitoring the coil voltage drop in the current sharing regime. Such an operation was made possible thanks to the very high stability of the conductor. The aim of these tests was to compare the critical properties of the conductor with expectations and assess the ITER TF conductor design. These expectations are based on the documented critical field and temperature dependent properties of the 720 superconducting strands which compose the conductor. In addition the conductor properties are highly dependent on the strain, due to the compression appearing on Nb 3 Sn during the heat treatment of the pancakes and related to the differential thermal compression between Nb 3 Sn and the stainless steel jacket. No precise model exists to predict this strain, which is therefore the main information, which is expected from these tests. The method to deduce this strain from the different tests is presented, including a thermalhydraulic analysis to identify the temperature of the critical point and a careful estimation of the field map across the conductor. The measured strain has been estimated in the range -0.75% to -0.79 %. This information will be taken into account for ITER design and some adjustment of the ITER conductor design is under examination. (authors)

Hierarchical Pd-Sn alloy nanosheet dendrites: an economical and highly active catalyst for ethanol electrooxidation.

Science.gov (United States)

Ding, Liang-Xin; Wang, An-Liang; Ou, Yan-Nan; Li, Qi; Guo, Rui; Zhao, Wen-Xia; Tong, Ye-Xiang; Li, Gao-Ren

2013-01-01

Hierarchical alloy nanosheet dendrites (ANSDs) are highly favorable for superior catalytic performance and efficient utilization of catalyst because of the special characteristics of alloys, nanosheets, and dendritic nanostructures. In this paper, we demonstrate for the first time a facile and efficient electrodeposition approach for the controllable synthesis of Pd-Sn ANSDs with high surface area. These synthesized Pd-Sn ANSDs exhibit high electrocatalytic activity and superior long-term cycle stability toward ethanol oxidation in alkaline media. The enhanced electrocataytic activity of Pd-Sn ANSDs may be attributed to Pd-Sn alloys, nanosheet dendrite induced promotional effect, large number of active sites on dendrite surface, large surface area, and good electrical contact with the base electrode. Because of the simple implement and high flexibility, the proposed approach can be considered as a general and powerful strategy to synthesize the alloy electrocatalysts with high surface areas and open dendritic nanostructures.

Microstructural Evolution of Ni-Sn Transient Liquid Phase Sintering Bond during High-Temperature Aging

Science.gov (United States)

Feng, Hongliang; Huang, Jihua; Peng, Xianwen; Lv, Zhiwei; Wang, Yue; Yang, Jian; Chen, Shuhai; Zhao, Xingke

2018-05-01

For high-temperature-resistant packaging of new generation power chip, a chip packaging simulation structure of Ni/Ni-Sn/Ni was bonded by a transient liquid-phase sintering process. High-temperature aging experiments were carried out to investigate joint heat stability. The microstructural evolution and mechanism during aging, and mechanical properties after aging were analyzed. The results show that the 30Ni-70Sn bonding layer as-bonded at 340°C for 240 min is mainly composed of Ni3Sn4 and residual Ni particles. When aged at 350°C, because of the difficulty of nucleation for Ni3Sn and quite slow growth of Ni3Sn2, the bonding layer is stable and the strength of that doesn't change obviously with aging time. When aging temperature increased to 500°C, however, the residual Ni particles were gradually dissolved and the bonding layer formed a stable structure with dominated Ni3Sn2 after 36 h. Meanwhile, due to the volume shrinkage (4.43%) from Ni3Sn2 formation, a number of voids were formed. The shear strength shows an increase, resulting from Ni3Sn2 formation, but then it decreases slightly caused by voids. After aging at 500°C for 100 h, shear strength is still maintained at 29.6 MPa. In addition, the mechanism of void formation was analyzed and microstructural evolution model was also established.

R and D of Nb(3)Sn accelerator magnets at Fermilab

International Nuclear Information System (INIS)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E; Bordini, B.; Bossert, R.; Carcagno, R.; Chichili, D.R.; DiMarco, J.; Elementi, L.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Kephart, R.; Lamm, M.; Limon, P.J.; Novitski, I.; Orris, D.; Pischalnikov, Yu.; Schlabach, P.; Stanek, R.

2004-01-01

Fermilab is developing and investigating different high-field magnet designs for present and future accelerators. The magnet RandD program was focused on the 10-12 T accelerator magnets based on Nb 3 Sn superconductor and explored both basic magnet technologies for brittle superconductors--wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC are being performed. A series of 1-m long single-bore models of cos-theta Nb 3 Sn dipoles based on wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and wide reacted Nb 3 Sn cable, have also been fabricated and tested. Extensive theoretical studies of magnetic instabilities in Nb 3 Sn strands, cable and magnet were performed which led to successful 10 T dipole model. This paper presents the details of the Fermilab's high field accelerator magnet program, reports its status and major results, and formulates the program next steps

R and D of Nb(3)Sn accelerator magnets at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E; Bordini, B.; Bossert, R.; Carcagno, R.; Chichili, D.R.; DiMarco, J.; Elementi, L.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Kephart, R.; Lamm, M.; Limon, P.J.; Novitski, I.; Orris, D.; Pischalnikov, Yu.; Schlabach, P.; Stanek, R.; /Fermilab

2004-11-01

Fermilab is developing and investigating different high-field magnet designs for present and future accelerators. The magnet R&D program was focused on the 10-12 T accelerator magnets based on Nb{sub 3}Sn superconductor and explored both basic magnet technologies for brittle superconductors--wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC are being performed. A series of 1-m long single-bore models of cos-theta Nb{sub 3}Sn dipoles based on wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and wide reacted Nb{sub 3}Sn cable, have also been fabricated and tested. Extensive theoretical studies of magnetic instabilities in Nb{sub 3}Sn strands, cable and magnet were performed which led to successful 10 T dipole model. This paper presents the details of the Fermilab's high field accelerator magnet program, reports its status and major results, and formulates the program next steps.

Nanostructure Sn-Co-C composite lithium ion battery electrode with unique stability and high electrochemical performance

International Nuclear Information System (INIS)

Li Mengyuan; Liu Chunling; Shi Meirong; Dong Wensheng

2011-01-01

Nanostructure Sn-Co-C composites with different compositions are synthesized by a simple solution polymerization using inexpensive raw materials followed by pyrolysis in nitrogen atmosphere. The nanostructure Sn-Co-C composites are characterized using various analytic techniques. The results show that the electrochemical performances of the composites are strongly dependent on their structure and composition. Among these composites the Sn-Co-C-1 with a weight composition of Sn 0.31 Co 0.09 C 0.6 exhibits high reversible capacity and excellent cycleability when used as an anode for rechargeable lithium ion batteries. This composite is composed of SnCo 2 , SnCo, Sn and amorphous carbon, and the nanoparticles of SnCo 2 , SnCo and Sn are uniformly dispersed into the amorphous carbon matrix, the average diameter of these metal nanoparticles is 8.44 nm.

Flux pinning characteristics of Sn-doped YBCO film by the MOD process

International Nuclear Information System (INIS)

Choi, S.M.; Shin, G.M.; Yoo, S.I.

2013-01-01

Highlights: ► The pinning effects of undoped and Sn-doped YBCO films by MOD were characterized. ► Sn-containing nanoparticles were trapped in Sn-doped YBCO films by MOD. ► Sn-containing nanoparticles were identified as the YBa 2 SnO 5.5 (YBSO) phase by TEM. ► The YBSO nanoparticles are responsible for improved flux pinning effect. ► We report the orientation relationship between YBSO nanoparticles and YBCO matrix. -- Abstract: Compared with the undoped YBa 2 Cu 3 O 7−δ (YBCO) film, 10 mol% Sn-doped YBCO film exhibited significantly enhanced critical current densities (J c ) in magnetic fields up to 5 T at 65 and 77 K for H//c, indicating that the Sn-doped YBCO film possesses more effective flux pinning centers. Both samples were grown on the SrTiO 3 (STO) (1 0 0) single crystal substrates by the metal-organic deposition (MOD) process. Larger J c (77 K, 1 T) values of Sn-doped YBCO film are observed over a wide field-orientation angle (θ) except the field-orientations close to the ab-plane of YBCO (85° c values for 85° 2 SnO 5.5 (YBSO) phase by STEM (scanning transmission electron microscopy)-EDS (energy dispersive X-ray spectroscopy) analysis. Further analyses by HR-TEM (high resolution-transmission electron microscopy) revealed that YBSO nanoparticles completely surrounded by the YBCO matrix had random orientation with YBCO while those located at the interface of YBCO/STO substrate had epitaxial relationship with YBCO

Impact of thickness on the structural properties of high tin content GeSn layers

Science.gov (United States)

Aubin, J.; Hartmann, J. M.; Gassenq, A.; Milord, L.; Pauc, N.; Reboud, V.; Calvo, V.

2017-09-01

We have grown various thicknesses of GeSn layers in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition cluster tool using digermane (Ge2H6) and tin tetrachloride (SnCl4). The growth pressure (100 Torr) and the F(Ge2H6)/F(SnCl4) mass-flow ratio were kept constant, and incorporation of tin in the range of 10-15% was achieved with a reduction in temperature: 325 °C for 10% to 301 °C for 15% of Sn. The layers were grown on 2.5 μm thick Ge Strain Relaxed Buffers, themselves on Si(0 0 1) substrates. We used X-ray Diffraction, Atomic Force Microscopy, Raman spectroscopy and Scanning Electron Microscopy to measure the Sn concentration, the strain state, the surface roughness and thickness as a function of growth duration. A dramatic degradation of the film was seen when the Sn concentration and layer thickness were too high resulting in rough/milky surfaces and significant Sn segregation.

Superconductivity optimization and phase formation kinetics study of internal-Sn Nb{sub 3}Sn superconducting wires

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chaowu

2007-07-15

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

Low-field Instabilities in Nb$_{3}$Sn Multifilamentary Wires the Possible Role of Unreacted Nb

CERN Document Server

Devred, A; Celentano, G; Fabbricatore, P; Ferdeghini, C; Greco, M; Gambardella, U

2007-01-01

We report an experimental study aiming to demonstrate the not negligible role of unreacted Nb on the magnetic instabilities in superconducting Nb$_{3}$Sn multifilamentary wires, observable through partial flux jumps at magnetic field values below 0.5 T. The analysed wires were recently developed for use as dipoles required in future high-energy proton accelerators and are based on powder-in-tube technology. We studied both unreacted (only involving Nb filaments) and reacted wires, finding flux jump instabilities in both cases when performing magnetic measurements. The results can be interpreted on the basis of the critical state model and are coherent with the intrinsic stability criterion.

Development of an experimental 10 T Nb3Sn dipole magnet for the CERN LHC

NARCIS (Netherlands)

ten Kate, H.H.J.; den Ouden, A.; ter Avest, D.; Wessel, S.; Dubbeldam, R.; van Emden, W.; Daum, C.; Bona, M.; Perin, R.

1991-01-01

An experimental 1-m long twill aperture dipole magnet developed using a high-current Nb3Sn conductor in order to attain a magnetic field well beyond 10 T at 4.2 K is described. The emphasis in this Nb3Sn project is on the highest possible field within the known Large Hadron Collider (LHC)

Self-Assembled Cu-Sn-S Nanotubes with High (De)Lithiation Performance.

Science.gov (United States)

Lin, Jie; Lim, Jin-Myoung; Youn, Duck Hyun; Kawashima, Kenta; Kim, Jun-Hyuk; Liu, Yang; Guo, Hang; Henkelman, Graeme; Heller, Adam; Mullins, Charles Buddie

2017-10-24

Through a gelation-solvothermal method without heteroadditives, Cu-Sn-S composites self-assemble to form nanotubes, sub-nanotubes, and nanoparticles. The nanotubes with a Cu 3-4 SnS 4 core and Cu 2 SnS 3 shell can tolerate long cycles of expansion/contraction upon lithiation/delithiation, retaining a charge capacity of 774 mAh g -1 after 200 cycles with a high initial Coulombic efficiency of 82.5%. The importance of the Cu component for mitigation of the volume expansion and structural evolution upon lithiation is informed by density functional theory calculations. The self-generated template and calculated results can inspire the design of analogous Cu-M-S (M = metal) nanotubes for lithium batteries or other energy storage systems.

Coulomb excitation of doubly magic $^{132}$Sn with MINIBALL at HIE-ISOLDE

CERN Multimedia

We propose to study the vibrational first 2$^{+}$ and 3$^{-}$ states of the doubly magic nucleus $^{132}$ Sn via Coulomb excitation using the HIE-ISOLDE facility coupled with the highly efficient MINIBALL array. The intense $^{132}$Sn beam at ISOLDE, the high beam energy of HIE-ISOLDE, the high energy resolution and good efficiency of the MINIBALL provide a unique combination and favourable advantages to master this demanding measurement. Reliable B(E2;0$^{+}\\rightarrow$ 2$^{+}$) values for neutron deficient $^{106,108,110}$Sn were obtained with the MINIBALL at REX-ISOLDE. These measurements can be extended up to and beyond the shell closure at the neutron-rich side with $^{132}$Sn. The results on excited collective states in $^{132}$Sn will provide crucial information on 2p-2h cross shell configurations which are expected to be dominated by a strong proton contribution. Predictions are made within various large scale shell model calculations and new mean field calculations within the framework of different a...

Statistical analysis of the Nb3Sn strand production for the ITER toroidal field coils

NARCIS (Netherlands)

Vostner, A.; Jewell, M.C.; Pong, I.; Sullivan, N.; Devred, A.; Bessette, D.; Bevillard, G.; Mitchell, N.; Romano, G.; Zhou, Chao

2017-01-01

The ITER toroidal field (TF) strand procurement initiated the largest Nb3Sn superconducting strand production hitherto. The industrial-scale production started in Japan in 2008 and finished in summer 2015. Six ITER partners (so-called Domestic Agencies, or DAs) are in charge of the procurement and

Improved multifilamentary Nb3Sn conductors produced by the titanium-bronze process

International Nuclear Information System (INIS)

Tachikawa, K.; Itoh, K.; Kamata, K.; Moriai, H.; Tada, N.

1985-01-01

The effects of a titanium addition to the bronze matrix of superconducting Nb 3 Sn wires have been investigated. The titanium addition to the matrix remarkably increases the Nb 3 Sn growth rate and the high-field, critical current density of the wire. An overall critical-current density of 3.8 . 10 4 A/cm 2 at 15 T has been obtained for the multifilamentary Nb/Cu-7.5 at.% Sn-0.4 at.% Ti wire with 4.7 μm-diameter 31 x 331 cores. The anisotropy in the critical current with respect to the field direction becomes larger with increasing aspect ratio of the rectangular-shaped multifilamentary wires. A 9.5 mm wide and 1.8mm thick Nb/Cu-7.5Sn-0.4Ti conductor with 5 μm-diameter 349 x 361=125 989 cores has been successfully fabricated on an industrial scale. This conductor carries a superconducting current of over 1300 A at 16.5 T. The newly developed Ti-bronze Nb 3 Sn conductor makes it feasible to generate a field of proportional 15 T in a large diameter bore. (orig.)

Low-field anomalous magnetic phase in the kagome-lattice shandite Co3Sn2S2

OpenAIRE

Kassem, Mohamed A.; Tabata, Yoshikazu; Waki, Takeshi; Nakamura, Hiroyuki

2017-01-01

The magnetization process of single crystals of the metallic kagom\\'e ferromagnet Co3Sn2S2 was carefully measured via magnetization and AC susceptibility. Field-dependent anomalous transitions in the magnetization indicate a low-field unconventionally ordered phase stabilized just below TC. The magnetic phase diagrams in applied fields along different crystallographic directions were determined. The magnetic relaxation process studied in frequencies covering five orders of magnitude from 0.01...

High field Nb/sub 3/Sn Axicell insert coils for the Mirror Fusion Test Facility-B (MFTF-B) axicell configuration. Final report

Energy Technology Data Exchange (ETDEWEB)

Baldi, R.W.; Tatro, R.E.; Scanlan, R.M.; Agarwal, K.L.; Bailey, R.E.; Burgeson, J.E.; Kim, I.K.; Magnuson, G.D.; Mallett, B.D.; Pickering, J.L.

1984-03-01

Two 12-tesla superconducting insert coils are being designed by General Dynamics Convair Division for the axicell regions of MFTF-B for Lawrence Livermore National Laboratory. A major challenge of this project is to ensure that combined fabrication and operational strains induced in the conductor are within stringent limitations of the relatively brittle Nb/sub 3/Sn superconductor filaments. These coils are located in the axicell region of MFTF-B. They have a clear-bore diameter of 36.195cm (14.25 inches) and consist of 27 double pancakes (i.e., 54 pancakes per coil) would on an electrically insulated 304LN stainless steel/bobbin helium vessel. Each pancake has 57 turns separated by G-10CR insulation. The complete winding bundle has 4.6 million ampere-turns and uniform current density of 2007 A/cm/sup 2/. In conjunction with the other magnets in the system, they produce a 12-tesla central field and a 12.52-tesla peak field. A multifilamentary Nb/sub 3/Sn conductor was selected to meet these requirements. The conductor consists of a monolithic insert soldered into a copper stabilizer. Sufficient cross-sectional area and work-hardening of the copper stabilizer has been provided for the conductor to self-react the electromagnetic Lorentz force induced hoop stresses with normal operational tensile strains less than 0.07 percent.

Ultrasonic synthesis of In-doped SnS nanoparticles and their physical properties

Science.gov (United States)

Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

2018-05-01

Indium (In)-doped Tin (II) Sulfide (SnS) nanoparticles (NPs) were synthesized by an ultra-sonication method and their optical, electrical, dielectric and photocatalytic properties were investigated. XRD patterns of the obtained NPs indicated formation of orthorhombic polycrystalline SnS. Field emission scanning electron microscopy exhibited flower-like NPs with particle sizes below 100 nm for both SnS and In-doped SnS samples. Optical analysis showed a decrease in energy band gap of SnS NPs upon In doping. In addition, electrical results demonstrated p-type nature of the synthesized SnS NPs and enhanced electrical conductivity of the NPs due to increased tin vacancy. Dielectric experiments on SnS NPs suggested an electronic polarizations effect to be responsible for changing dielectric properties of the particles, in terms of frequency. Finally, photocatalytic experiments revealed that high degradation power can be obtained using In-doped SnS NPs.

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

International Nuclear Information System (INIS)

Masek, J.; Nuzhnyj, D.N.

1997-01-01

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

Modification of SnO2 Anodes by Atomic Layer Deposition for High Performance Lithium Ion Batteries

KAUST Repository

Yesibolati, Nulati

2013-05-01

Tin dioxide (SnO2) is considered one of the most promising anode materials for Lithium ion batteries (LIBs), due to its large theoretical capacity and natural abundance. However, its low electronic/ionic conductivities, large volume change during lithiation/delithiation and agglomeration prevent it from further commercial applications. In this thesis, we investigate modified SnO2 as a high energy density anode material for LIBs. Specifically two approaches are presented to improve battery performances. Firstly, SnO2 electrochemical performances were improved by surface modification using Atomic Layer Deposition (ALD). Ultrathin Al2O3 or HfO2 were coated on SnO2 electrodes. It was found that electrochemical performances had been enhanced after ALD deposition. In a second approach, we implemented a layer-by-layer (LBL) assembled graphene/carbon-coated hollow SnO2 spheres as anode material for LIBs. Our results indicated that the LBL assembled electrodes had high reversible lithium storage capacities even at high current densities. These superior electrochemical performances are attributed to the enhanced electronic conductivity and effective lithium diffusion, because of the interconnected graphene/carbon networks among nanoparticles of the hollow SnO2 spheres.

Highly active carbon supported ternary PdSnPtx (x=0.1-0.7) catalysts for ethanol electro-oxidation in alkaline and acid media.

Science.gov (United States)

Wang, Xiaoguang; Zhu, Fuchun; He, Yongwei; Wang, Mei; Zhang, Zhonghua; Ma, Zizai; Li, Ruixue

2016-04-15

A series of trimetallic PdSnPtx (x=0.1-0.7)/C catalysts with varied Pt content have been synthesized by co-reduction method using NaBH4 as a reducing agent. These catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and chronoamperometry (CA). The electrochemical results show that, after adding a minor amount of Pt dopant, the resultant PdSnPtx/C demonstrated more superior catalytic performance toward ethanol oxidation as compared with that of mono-/bi-metallic Pd/C or PdSn/C in alkaline solution and the PdSnPt0.2/C with optimal molar ratio reached the best. In acid solution, the PdSnPt0.2/C also depicted a superior catalytic activity relative to the commercial Pt/C catalyst. The possible enhanced synergistic effect between Pd, Sn/Sn(O) and Pt in an alloyed state should be responsible for the as-revealed superior ethanol electro-oxidation performance based upon the beneficial electronic effect and bi-functional mechanism. It implies the trimetallic PdSnPt0.2/C with a low Pt content has a promising prospect as anodic electrocatalyst in fields of alkali- and acid-type direct ethanol fuel cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Nano-grain SnO{sub 2} electrodes for high conversion efficiency SnO{sub 2}-DSSC

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung-Hoon; Shin, Yu-Ju [Department of Chemistry, the Catholic University of Korea, Bucheon, Gyeonggi-do 422-743 (Korea, Republic of); Park, Nam-Gyu [School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

2011-01-15

The nano-grain ZnO/SnO{sub 2} composite electrode was prepared by adding 5 w% of the 200-250 nm ZnO particles to the 5 nm SnO{sub 2} colloid in the presence of hydroxypropylcellulose (M.W.=80,000). The nano-grain SnO{sub 2} electrode was obtained by removing the ZnO particles from the composite electrode using acetic acid. The FE-SEM micrographs revealed that both electrodes consisted of interconnected nano-grains that were ca. 800 nm in size, and the large pores between the grains furnished the wide electrolyte diffusion channels within the electrodes. The photovoltaic properties of the nano-grain electrodes were investigated by measuring the I-V behaviors, the IPCE spectra and the ac-impedance spectra. The nano-grain electrodes exhibited remarkably improved conversion efficiencies of 3.96% for the composite and 2.98% for the SnO{sub 2} electrode compared to the value of 1.66% for the usual nano-particle SnO{sub 2} electrode. The improvement conversion efficiencies were mainly attributed to the formation of nano-grains, which facilitated the electron diffusion within the grains. The improved electrolyte diffusion as well as the light-scattering effects enhanced the photovoltaic performance of the SnO{sub 2} electrode. (author)

SnO2 nanocrystals anchored on N-doped graphene for high-performance lithium storage.

Science.gov (United States)

Zhou, Wei; Wang, Jinxian; Zhang, Feifei; Liu, Shumin; Wang, Jianwei; Yin, Dongming; Wang, Limin

2015-02-28

A SnO2-N-doped graphene (SnO2-NG) composite is synthesized by a rapid, facile, one-step microwave-assisted solvothermal method. The composite exhibits excellent lithium storage capability and high durability, and is a promising anode material for lithium ion batteries.

Dimensional Changes of Nb$_{3}$Sn Rutherford Cables During Heat Treatment

CERN Document Server

Rochepault, E; Ambrosio, G; Anerella, M; Ballarino, A; Bonasia, A; Bordini, B; Cheng, D; Dietderich, D R; Felice, H; Garcia Fajardo, L; Ghosh, A; Holik, E F; Izquierdo Bermudez, S; Perez, J C; Pong, I; Schmalzle, J; Yu, M

2016-01-01

In high field magnet applications, Nb$_{3}$Sn coils undergo a heat treatment step after winding. During this stage, coils radially expand and longitudinally contract due to the Nb$_{3}$Sn phase change. In order to prevent residual strain from altering superconducting performances, the tooling must provide the adequate space for these dimensional changes. The aim of this paper is to understand the behavior of cable dimensions during heat treatment and to provide estimates of the space to be accommodated in the tooling for coil expansion and contraction. This paper summarizes measurements of dimensional changes on strands, single Rutherford cables, cable stacks, and coils performed between 2013 and 2015. These samples and coils have been performed within a collaboration between CERN and the U.S. LHC Accelerator Research Program to develop Nb$_{3}$Sn quadrupole magnets for the HiLumi LHC. The results are also compared with other high field magnet projects.

Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

Science.gov (United States)

Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

2010-02-01

Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water

Production and testing of an s-band resonator with a Nb3Sn surface

International Nuclear Information System (INIS)

Peiniger, M.

1983-01-01

This report describes the preparation of a niobium s-band resonator with Nb3Sn surface using a special vapor phase deposition method. High-frequency superconductivity tests were performed on this resonator. Measurements of transition temperature, penetration depth, energy gap, and temperature dependence of surface conductivity of Nb3Sn, and resonator behaviour at high electrical field strengths are reported. (GSCH)

Dielectric and magnetic properties of (Zn, Co) co-doped SnO2 nanoparticles

International Nuclear Information System (INIS)

Rajwali, Khan; Fang Ming-Hu

2015-01-01

Polycrystalline samples of (Zn, Co) co-doped SnO 2 nanoparticles were prepared using a co-precipitation method. The influence of (Zn, Co) co-doping on electrical, dielectric, and magnetic properties was studied. All of the (Zn, Co) co-doped SnO 2 powder samples have the same tetragonal structure of SnO 2 . A decrease in the dielectric constant was observed with the increase of Co doping concentration. It was found that the dielectric constant and dielectric loss values decrease, while AC electrical conductivity increases with doping concentration and frequency. Magnetization measurements revealed that the Co doping SnO 2 samples exhibits room temperature ferromagnetism. Our results illustrate that (Zn, Co) co-doped SnO 2 nanoparticles have an excellent dielectric, magnetic properties, and high electrical conductivity than those reported previously, indicating that these (Zn, Co) co-doped SnO 2 materials can be used in the field of the ultrahigh dielectric material, high frequency device, and spintronics. (paper)

Highly efficient electrochemical degradation of perfluorooctanoic acid (PFOA) by F-doped Ti/SnO{sub 2} electrode

Energy Technology Data Exchange (ETDEWEB)

Yang, Bo, E-mail: boyang@szu.edu.cn [Department of Environmental Engineering, College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060 (China); School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China); Jiang, Chaojin [Department of Environmental Engineering, College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060 (China); Yu, Gang, E-mail: yg-den@tsinghua.edu.cn [School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China); Zhuo, Qiongfang [South China Institute of Environmental Sciences, The Ministry of Environment Protection, Guangzhou 510655 (China); Deng, Shubo [School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China); Wu, Jinhua [School of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Zhang, Hong [Department of Environmental Engineering, College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060 (China)

2015-12-15

Highlights: • A novel SnO{sub 2} electrode is prepared by F doping instead of the traditional Sb doping. • SnF{sub 4} as single-source precursor is used to fabricate the long-life Ti/SnO{sub 2}–F anode. • F-doped Ti/SnO{sub 2} anode possesses high OEP and decomposition ability for PFOA. • Further mechanistic detail of PFOA degradation on Ti/SnO{sub 2}–F electrode is proposed. - Abstract: The novel F-doped Ti/SnO{sub 2} electrode prepared by SnF{sub 4} as the single-source precursor was used for electrochemical degradation of aqueous perfluorooctanoic acid (PFOA). Higher oxidation reactivity and significantly longer service life were achieved for Ti/SnO{sub 2}–F electrode than Ti/SnO{sub 2}–X (X = Cl, Br, I, or Sb) electrode, which could decomposed over 99% of PFOA (50 mL of 100 mg L{sup −1}) within 30-min electrolysis. The property of Ti/SnO{sub 2}–F electrode and its electrooxidation mechanism were investigated by XRD, SEM–EDX, EIS, LSV, and interfacial resistance measurements. We propose that the similar ionic radii of F and O as well as strong electronegativity of F caused its electrochemical stability with high oxygen evolution potential (OEP) and smooth surface to generate weakly adsorbed ·OH. The preparation conditions of electrode were also optimized including F doping amount, calcination temperature, and dip coating times, which revealed the formation process of electrode. Additionally, the major mineralization product, F{sup −}, and low concentration of shorter chain perfluorocarboxylic acids (PFCAs) were detected in solution. So the reaction pathway of PFOA electrooxidation was proposed by intermediate analysis. These results demonstrate that Ti/SnO{sub 2}–F electrode is promising for highly efficient treatment of PFOA in wastewater.

A New Understanding of the Heat Treatment of Nb-Sn Superconducting Wires

Science.gov (United States)

Sanabria, Charlie

Enhancing the beam energy of particle accelerators like the Large Hadron Collider (LHC), at CERN, can increase our probability of finding new fundamental particles of matter beyond those predicted by the standard model. Such discoveries could improve our understanding of the birth of universe, the universe itself, and/or many other mysteries of matter--that have been unresolved for decades--such as dark matter and dark energy. This is obviously a very exciting field of research, and therefore a worldwide collaboration (of universities, laboratories, and the industry) is attempting to increase the beam energy in the LHC. One of the most challenging requirements for an energy increase is the production of a magnetic field homogeneous enough and strong enough to bend the high energy particle beam to keep it inside the accelerating ring. In the current LHC design, these beam bending magnets are made of Nb Ti superconductors, reaching peak fields of 8 T. However, in order to move to higher fields, future magnets will have to use different and more advanced superconducting materials. Among the most viable superconductor wire technologies for future particle accelerator magnets is Nb3Sn, a technology that has been used in high field magnets for many decades. However, Nb3Sn magnet fabrication has an important challenge: the fact the wire fabrication and the coil assembly itself must be done using ductile metallic components (Nb, Sn, and Cu) before the superconducting compound (Nb3 Sn) is activated inside the wires through a heat treatment. The studies presented in this thesis work have found that the heat treatment schedule used on the most advanced Nb3Sn wire technology (the Restacked Rod Process wires, RRPRTM) can still undergo significant improvements. These improvements have already led to an increase of the figure of merit of these wires (critical current density) by 28%.

Mechanical design of a high field common coil magnet

CERN Document Server

Caspi, S; Dietderich, D R; Gourlay, S A; Gupta, R; McInturff, A; Millos, G; Scanlan, R M

1999-01-01

A common coil design for high field 2-in-1 accelerator magnets has been previously presented as a "conductor-friendly" option for high field magnets applicable for a Very Large Hadron Collider. This paper presents the mechanical design for a 14 tesla 2-in-1 dipole based on the common coil design approach. The magnet will use a high current density Nb/sub 3/Sn conductor. The design addresses mechanical issues particular to the common coil geometry: horizontal support against coil edges, vertical preload on coil faces, end loading and support, and coil stresses and strains. The magnet is the second in a series of racetrack coil magnets that will provide experimental verification of the common coil design approach. (9 refs).

Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation

International Nuclear Information System (INIS)

Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook

2017-01-01

Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.

Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation

Energy Technology Data Exchange (ETDEWEB)

Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook, E-mail: cwjeon@ynu.ac.kr

2017-04-30

Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.

Hierarchical SnO2-Graphite Nanocomposite Anode for Lithium-Ion Batteries through High Energy Mechanical Activation

International Nuclear Information System (INIS)

Ng, Vincent Ming Hong; Wu, Shuying; Liu, Peijiang; Zhu, Beibei; Yu, Linghui; Wang, Chuanhu; Huang, Hui; Xu, Zhichuan J.; Yao, Zhengjun; Zhou, Jintang; Que, Wenxiu; Kong, Ling Bing

2017-01-01

Highlights: •A simple and scalable process to concomitant downsizing to nanoscale, carbon coating, inclusion of voids and conductive network of graphite. •Using tungsten carbide milling media and 80:1 ball to powder ratio, micron SnO 2 particles are comminuted to nanosized SnO 2 crystallites. •Hierarchical structure of carbon-coated SnO2 nanoclusters anchored on thin graphite sheets are prepared. •Impressive reversible capacity of 725 mAh g −1 is achieved by ball milling a mixture of SnO 2 with 20 wt. % graphite for 20 h. •Synthesis parameters such as graphite content and milling time are systematically examined. -- Abstract: Development of novel electrode materials with unique architectural designs is necessary to attain high power and energy density lithium-ion batteries (LIBs). SnO 2 , with high theoretical capacity of 1494 mAh g −1 , is a promising candidate anode material, which has been explored with various strategies, such as dimensional reduction, morphological modifications and composite formation. Unfortunately, most of the SnO 2 -based electrodes are prepared by using complex chemical synthesis methods, which are not feasible to scale up for practical applications. In addition, concomitant irrecoverable initial capacity loss and consequently poor initial Coulombic efficiency still persistently plagued these SnO 2 -based anodes. To overcome hitherto conceived irreversible formation of Li 2 O by conversion reaction, to fully harness its theoretical capacity, this work demonstrates that a hierarchical structured SnO 2 -C nanocomposite with 68.5% initial Coulombic efficiency and reversible capacity of 725 mAh g −1 can be derived from the mixtures of SnO 2 and graphite, by using low cost industrial compatible high energy ball milling activation.

Hierarchical three-dimensional porous SnS{sub 2}/carbon cloth anode for high-performance lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Chao, Junfeng, E-mail: chchjjff@163.com [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Zhang, Xiutai [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Xing, Shumin [College of Mathematics and Physics, Anyang Institute of Technology, Anyang 455000 (China); Fan, Qiufeng; Yang, Junping; Zhao, Luhua; Li, Xiang [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China)

2016-08-15

Graphical abstract: Hierarchical 3D porous SnS{sub 2}/carbon cloth, good electrochemical performance. - Highlights: • Hierarchical 3D porous SnS{sub 2}/carbon cloth has been firstly synthesized. • The SnS{sub 2}/carbon clothes were good candidates for excellent lithium ion batteries. • The SnS{sub 2}/carbon cloth exhibits improved capacity compared to pure SnS{sub 2}. - Abstract: Hierarchical three-dimension (3D) porous SnS{sub 2}/carbon clothes were synthesized via a facile polyol refluxing process. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmet–Teller (BET) and UV–vis diffuse reflectance spectrometer (UV–vis DRS). The 3D porous SnS{sub 2}/carbon clothes-based lithium ion batteries exhibited high reversible capacity and good rate capability as anode materials. The good electrochemical performance for lithium ion storage could be attributed to the special nanostructure, leading to high-rate transportation of electrolyte ion and electrons throughout the electrode matrix.

Metallic Sn-Based Anode Materials: Application in High-Performance Lithium-Ion and Sodium-Ion Batteries.

Science.gov (United States)

Ying, Hangjun; Han, Wei-Qiang

2017-11-01

With the fast-growing demand for green and safe energy sources, rechargeable ion batteries have gradually occupied the major current market of energy storage devices due to their advantages of high capacities, long cycling life, superior rate ability, and so on. Metallic Sn-based anodes are perceived as one of the most promising alternatives to the conventional graphite anode and have attracted great attention due to the high theoretical capacities of Sn in both lithium-ion batteries (LIBs) (994 mA h g -1 ) and sodium-ion batteries (847 mA h g -1 ). Though Sony has used Sn-Co-C nanocomposites as its commercial LIB anodes, to develop even better batteries using metallic Sn-based anodes there are still two main obstacles that must be overcome: poor cycling stability and low coulombic efficiency. In this review, the latest and most outstanding developments in metallic Sn-based anodes for LIBs and SIBs are summarized. And it covers the modification strategies including size control, alloying, and structure design to effectually improve the electrochemical properties. The superiorities and limitations are analyzed and discussed, aiming to provide an in-depth understanding of the theoretical works and practical developments of metallic Sn-based anode materials.

Flux pinning in bronze-processed Nb3Sn wires

International Nuclear Information System (INIS)

Suenaga, M.; Welch, D.O.

1980-01-01

The scaling law derived by Kramer for magnetic flux pinning in high magnetic fields was examined for its applicability to the magnetic field dependence of critical-current densities in the bronze processed monofilamentary Nb 3 Sn wires. From this it was concluded that: (1) its prediction for the form of the dependence of critical current on magnetic field and grain size [/J vector /sub c/ x H vector/ approx. h/sup 1/2/(1-h) 2 (1-a 0 √rho) -2 ] was found to be very good in most cases including wires with very small Nb 3 Sn grains (approx. 400 A). It was found very useful in comparison of J/sub c/ for different wires and in extrapolating to obtain H/sub c2/ for these wires. (2) However, it could not account consistently for the anisotropy in critical current of a tape which was measured with H applied perpendicular and parallel to the tape face. (3) The values of kappa 1 which were determined with the scaling law were too small by a factor of 2 to 3, and the trend in the variation with heat-treating time was opposite to that which is reasonably to be expected. That the behavior of kappa 1 is thus seriously in contradiction with the expected behavior for Nb 3 Sn suggests basic faults in the derivation of the scaling equation for critical currents at high magnetic fields

Gas Sensing Properties of ZnO-SnO2 Nanostructures.

Science.gov (United States)

Chen, Weigen; Li, Qianzhu; Xu, Lingna; Zeng, Wen

2015-02-01

One-dimensional (1D) semiconductor metal oxide nanostructures have attracted increasing attention in electrochemistry, optics, magnetic, and gas sensing fields for the good properties. N-type low dimensional semiconducting oxides such as SnO2 and ZnO have been known for the detection of inflammable or toxic gases. In this paper, we fabricated the ZnO-SnO2 and SnO2 nanoparticles by hydrothermal synthesis. Microstructure characterization was performed using X-ray diffraction (XRD) and surface morphologies for both the pristine and doped samples were observed using field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Then we made thin film gas sensor to study the gas sensing properties of ZnO-SnO2 and SnO2 gas sensor to H2 and CO. A systematic comparison study reveals an enhanced gas sensing performance for the sensor made of SnO2 and ZnO toward H2 and CO over that of the commonly applied undecorated SnO2 nanoparticles. The improved gas sensing properties are attributed to the size of grains and pronounced electron transfer between the compound nanostructures and the absorbed oxygen species as well as to the heterojunctions of the ZnO nanoparticles to the SnO2 nanoparticles, which provide additional reaction rooms. The results represent an advance of compound nanostructures in further enhancing the functionality of gas sensors, and this facile method could be applicable to many sensing materials, offering a new avenue and direction to detect gases of interest based on composite tin oxide nanoparticles.

Structural and elemental characterization of high efficiency Cu2ZnSnS4 solar cells

Science.gov (United States)

Wang, Kejia; Shin, Byungha; Reuter, Kathleen B.; Todorov, Teodor; Mitzi, David B.; Guha, Supratik

2011-01-01

We have carried out detailed microstructural studies of phase separation and grain boundary composition in Cu2ZnSnS4 based solar cells. The absorber layer was fabricated by thermal evaporation followed by post high temperature annealing on hot plate. We show that inter-reactions between the bottom molybdenum and the Cu2ZnSnS4, besides triggering the formation of interfacial MoSx, results in the out-diffusion of Cu from the Cu2ZnSnS4 layer. Phase separation of Cu2ZnSnS4 into ZnS and a Cu-Sn-S compound is observed at the molybdenum-Cu2ZnSnS4 interface, perhaps as a result of the compositional out-diffusion. Additionally, grain boundaries within the thermally evaporated absorber layer are found to be either Cu-rich or at the expected bulk composition. Such interfacial compound formation and grain boundary chemistry likely contributes to the lower than expected open circuit voltages observed for the Cu2ZnSnS4 devices.

Preparation of a porous Sn@C nanocomposite as a high-performance anode material for lithium-ion batteries

Science.gov (United States)

Zhang, Yanjun; Jiang, Li; Wang, Chunru

2015-07-01

A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries.A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries. Electronic supplementary information (ESI) available: Detailed experimental procedure and additional characterization, including a Raman spectrum, TGA curve, N2 adsorption-desorption isotherm, TEM images and SEM images. See DOI: 10.1039/c5nr03093e

Nanocrystalline CdSnO3 Based Room Temperature Methanol Sensor

Directory of Open Access Journals (Sweden)

Shanabhau BAGUL

2017-04-01

Full Text Available Synthesis of nanocrystalline CdSnO3 powder by ultrasonic atomizer assisted wet chemical method is reported in this paper. Synthesized CdSnO3 powder was characterized by X-Ray Diffraction (XRD, Field Emission Scanning Electron Microscopy (FESEM and Transmission Electron Microscopy (TEM to examine phase and microstructure. FESEM and TEM analysis reveals that the CdSnO3 powder prepared here is porous monodisperse nanocrystalline in nature, with average particle size of approximately 17 nm or smaller. The material is also characterized by UV-Visible and Photoluminescence (PL spectroscopy. Thick films of synthesized CdSnO3 powder fired at 850 0C are made by using screen printing method. The films surface is modified by using dipping method. CuCl2 (0.005 M dipped (for 2 min thick film shows high response (R= 477 to 100 ppm methanol at room temperature (35 0C. The sensor shows good selectivity and fast response recovery time to methanol. The excellent methanol sensing performance, particularly high response values is observed to be mainly due to porous CdSnO3 surface.

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

Fully transparent thin-film transistor devices based on SnO2 nanowires.

Science.gov (United States)

Dattoli, Eric N; Wan, Qing; Guo, Wei; Chen, Yanbin; Pan, Xiaoqing; Lu, Wei

2007-08-01

We report on studies of field-effect transistor (FET) and transparent thin-film transistor (TFT) devices based on lightly Ta-doped SnO2 nano-wires. The nanowire-based devices exhibit uniform characteristics with average field-effect mobilities exceeding 100 cm2/V x s. Prototype nano-wire-based TFT (NW-TFT) devices on glass substrates showed excellent optical transparency and transistor performance in terms of transconductance, bias voltage range, and on/off ratio. High on-currents and field-effect mobilities were obtained from the NW-TFT devices even at low nanowire coverage. The SnO2 nanowire-based TFT approach offers a number of desirable properties such as low growth cost, high electron mobility, and optical transparency and low operation voltage, and may lead to large-scale applications of transparent electronics on diverse substrates.

Finite Element Analysis of Transverse Compressive Loads on Superconducting Nb3Sn Wires Containing Voids

Science.gov (United States)

D'Hauthuille, Luc; Zhai, Yuhu; Princeton Plasma Physics Lab Collaboration; University of Geneva Collaboration

2015-11-01

High field superconductors play an important role in many large-scale physics experiments, particularly particle colliders and fusion devices such as the LHC and ITER. The two most common superconductors used are NbTi and Nb3Sn. Nb3Sn wires are favored because of their significantly higher Jc, allowing them to produce much higher magnetic fields. The main disadvantage is that the superconducting performance of Nb3Sn is highly strain-sensitive and it is very brittle. The strain-sensitivity is strongly influenced by two factors: plasticity and cracked filaments. Cracks are induced by large stress concentrators due to the presence of voids. We will attempt to understand the correlation between Nb3Sn's irreversible strain limit and the void-induced stress concentrations around the voids. We will develop accurate 2D and 3D finite element models containing detailed filaments and possible distributions of voids in a bronze-route Nb3Sn wire. We will apply a compressive transverse load for the various cases to simulate the stress response of a Nb3Sn wire from the Lorentz force. Doing this will further improve our understanding of the effect voids have on the wire's mechanical properties, and thus, the connection between the shape & distribution of voids and performance degradation.

The Effect of Increasing Sn Content on High-Temperature Mechanical Deformation of an Mg-3%Cu-1%Ca Alloy

Directory of Open Access Journals (Sweden)

Georgios S.E. Antipas

2013-11-01

Full Text Available Chill casting of magnesium alloy samples with secondary alloying elements of Cu, Ca and Sn at % w.t. concentrations in the range 1–5, 0.1–5 and 0.1–3 respectively, gave rise to appreciably enhanced resistance to high-temperature creep, while maintaining good heat conductivity. The latter was considered to be driven by Cu and Mg-Cu intermetallics while it was clear that Sn mediated the high-temperature performance, mainly via networks of Mg2Sn and MgCaSn precipitates along the Mg matrix grain boundaries. It was postulated that Sn formed intermetallics by preferential substitution of Ca atoms and, thus, did not degrade the heat conductivity by retaining Cu. The % w.t. stoichiometry with the optimum combination of heat conductivity and resistance to high-temperature creep was found to be Mg-3Cu-1Ca-0.1Sn.

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.

Recent Progress in Application of Internal Oxidation Technique in Nb3Sn Strands

Energy Technology Data Exchange (ETDEWEB)

Xu, Xingchen [Fermilab; Peng, Xuan [Hyper Tech Research Inc.; Sumption, Michael [Ohio State U.; Collings, E. W. [Ohio State U.

2016-10-13

The internal oxidation technique can generate ZrO2 nano particles in Nb3Sn strands, which markedly refine the Nb3Sn grain size and boost the high-field critical current density (Jc). This article summarizes recent efforts on implementing this technique in practical Nb3Sn wires and adding Ti as a dopant. It is demonstrated that this technique can be readily incorporated into the present Nb3Sn conductor manufacturing technology. Powder-in-tube (PIT) strands with fine subelements (~25 µm) based on this technique were successfully fabricated, and proper heat treatments for oxygen transfer were explored. Future work for producing strands ready for applications is proposed.

Ultrasmall SnO₂ nanocrystals: hot-bubbling synthesis, encapsulation in carbon layers and applications in high capacity Li-ion storage.

Science.gov (United States)

Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G

2014-04-15

Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA·h·g(-1) at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs.

Use of High Resolution DAQ System to Aid Diagnosis of HD2b, a High Performance Nb3Sn Dipole

International Nuclear Information System (INIS)

Lizarazo, J.; Doering, D.; Doolittle, L.; Galvin, J.; Caspi, S.; Dietderich, D.R.; Felice, H.; Ferracin, P.; Godeke, A.; Joseph, J.; Lietzke, A.F.; Ratti, A.; Sabbi, G.L.; Trillaud, F.; Wang, X.; Zimmerman, S.

2008-01-01

A novel voltage monitoring system to record voltage transients in superconducting magnets is being developed at LBNL. This system has 160 monitoring channels capable of measuring differential voltages of up to 1.5kV with 100kHz bandwidth and 500kS/s digitizing rate. This paper presents analysis results from data taken with a 16 channel prototype system. From that analysis we were able to diagnose a change in the current-temperature margin of the superconducting cable by analyzing Flux-Jump data collected after a magnet energy extraction failure during testing of a high field Nb 3 Sn dipole.

Use of High Resolution DAQ System to Aid Diagnosis of HD2b, a High Performance Nb3Sn Dipole

Energy Technology Data Exchange (ETDEWEB)

Lizarazo, J.; Doering, D.; Doolittle, L.; Galvin, J.; Caspi, S.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Godeke, A.; Joseph, J.; Lietzke, A. F.; Ratti, A.; Sabbi, G. L.; Trillaud, F.; Wang, X.; Zimmerman, S.

2008-08-17

A novel voltage monitoring system to record voltage transients in superconducting magnets is being developed at LBNL. This system has 160 monitoring channels capable of measuring differential voltages of up to 1.5kV with 100kHz bandwidth and 500kS/s digitizing rate. This paper presents analysis results from data taken with a 16 channel prototype system. From that analysis we were able to diagnose a change in the current-temperature margin of the superconducting cable by analyzing Flux-Jump data collected after a magnet energy extraction failure during testing of a high field Nb{sub 3}Sn dipole.

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.

Stress-strain effects in alumina-Cu reinforced Nb3Sn wires fabricated by the tube process

International Nuclear Information System (INIS)

Murase, Satoru; Nakayama, Shigeo; Masegi, Tamaki; Koyanagi, Kei; Nomura, Shunji; Shiga, Noriyuki; Kobayashi, Norio; Watanabe, Kazuo.

1997-01-01

In order to fabricate a large-bore, high-field magnet which achieves a low coil weight and volume, a high strength compound superconducting wire is required. For those demands we have developed the reinforced Nb 3 Sn wire using alumina dispersion strengthened copper (alumina-Cu) as a reinforcement material and the tube process of the Nb 3 Sn wire fabrication. The ductility study of the composites which consisted of the reinforcement, Nb tube, Cu, and Cu clad Sn brought a 1 km long alumina-Cu reinforced Nb 3 Sn wire successfully. Using fabricated wires measurements and evaluations of critical current density as parameters of magnetic field, tensile stress, tensile strain, and transverse compressive stress, and those of stress-strain curves at 4.2 K were performed. They showed superior performance such as high 0.3% proof stress (240 MPa at 0.3% strain) and high maximum tolerance stress (320 MPa) which were two times as large as those of conventional Cu matrix Nb 3 Sn wire. The strain sensitivity parameters were obtained for the reinforced Nb 3 Sn wire and the Cu matrix one using the scaling law. Residual stress of the component materials caused by cooling down to 4.2 K from heat-treatment temperature was calculated using equivalent Young's modulus, equivalent yield strength, thermal expansion coefficient and other mechanical parameters. Calculated stress-strain curves at 4.2 K for the reinforced Nb 3 Sn wire and the Cu matrix one based on calculation of residual stress, had good agreement with the experimental values. (author)

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.

Method for the manufacture of a superconductive Nb3Sn layer on a niobium surface for high frequency applications

International Nuclear Information System (INIS)

Martens, H.

1978-01-01

A manufacturing method for depositing an Nb 3 Sn layer on a niobium surface for high frequency applications comprising developing a tin vapor atmosphere which also contains a highly volatile tin compound in the gaseous state, and holding the portions of the surface which are to be provided with the Nb 3 Sn layer at a temperature of between 900 0 and 1500 0 C for a predetermined period of time to form the Nb 3 Sn layer permitting niobium surfaces of any shape to be provided with Nb 3 Sn layers of high uniformity and quality

Study of superconducting Nb3Sn coils

International Nuclear Information System (INIS)

Vivet, B.

1963-01-01

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

Investigation of superior electro-optical properties of SnO{sub 2}/SiO{sub 2} nanocomposite over its individual counterpart SnO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Naveen Kumar, P.; Sahaya Selva Mary, J.; Chandrakala, V.; Jothi Jeyarani, W.; Merline Shyla, J., E-mail: jmshyla@gmail.com

2017-06-01

A comparative investigation of SnO{sub 2}/SiO{sub 2} nanocomposite with SnO{sub 2} nanoparticles has been conducted in the present study with the intent of learning the probable enhancement of the properties of the nanocomposite over those of the bare nanoparticles which has not been widely reported before. SnO{sub 2} nanoparticles and SnO{sub 2}/SiO{sub 2} nanocomposite have been synthesized via the facile and versatile sol-gel method. The samples were characterized with X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), Brunauer Emmett Teller (BET) studies, Fourier Transform Infra-Red spectroscopy (FT-IR), UV–Visible (UV–Vis) spectroscopy and Field-dependent photo conductivity technique for the evaluation of their crystallite size, structure & morphology, surface, chemical, optical and electrical properties respectively. Scherrer’s equation was used to determine the crystallite size of the as-synthesized samples from the XRD data. The particle size of SnO{sub 2}/SiO{sub 2} nanocomposite as observed through HRSEM was found to be reduced when compared with the bare SnO{sub 2} nanoparticles suggesting a possible increase in the optical band gap of the former which has been further confirmed in the optical studies. The surface area of SnO{sub 2}/SiO{sub 2} nanocomposite revealed a remarkable enrichment by approximately 5 folds in comparison with that of SnO{sub 2} nanoparticles which suggests an enhancement in its corresponding optical and electrical properties. The SnO{sub 2}/SiO{sub 2} nanocomposite recorded appreciated values of field-dependent photo and dark currents with several folds of augmentation thereby qualifying as an efficient photoconducting material. Attributed with an improved surface area and increased photoconducting nature, the SnO{sub 2}/SiO{sub 2} nanocomposite could be presented as an excellent photoanode material for nanomaterials based Dye Sensitized Solar Cells (DSSCs). - Highlights: • SnO{sub 2}/SiO{sub 2

Advances in development of Nb3Sn superconducting radio-frequency cavities

Science.gov (United States)

Posen, Sam; Liepe, Matthias

2014-11-01

A 1.3 GHz Nb3Sn superconducting radio-frequency cavity prepared with a modified annealing step reached Bp k>50 mT , well above Bc 1=25 ±7 mT , without the strong Q -slope observed in previous Nb3Sn cavities. At 4.2 K, it has a Q0 of approximately 1 ×1 010 at >10 MV /m , far outperforming Nb at useable gradients. At 2 K, quench occurred at ˜55 mT , apparently due to a defect, so additional treatment may increase the maximum gradient. Material parameters of the coating were extracted from Q vs T data, including a Tc of 18.0 ±0.1 K , close to the maximum literature value. High power pulses were used to reach fields far higher than in CW measurements, and near Tc, quench fields close to the superheating field were observed. Based on a review of previous experience with Nb3Sn cavities, a speculative mechanism involving weak link grain boundaries is presented to explain how the modified annealing step could be the cause of the absence of strong Q -slope. Finally, an analysis of the progress to date provides hints that the path forward for Nb3Sn cavities should focus on minimizing defects.

Facile mechanochemical synthesis of nano SnO2/graphene composite from coarse metallic Sn and graphite oxide: an outstanding anode material for lithium-ion batteries.

Science.gov (United States)

Ye, Fei; Zhao, Bote; Ran, Ran; Shao, Zongping

2014-04-01

A facile method for the large-scale synthesis of SnO2 nanocrystal/graphene composites by using coarse metallic Sn particles and cheap graphite oxide (GO) as raw materials is demonstrated. This method uses simple ball milling to realize a mechanochemical reaction between Sn particles and GO. After the reaction, the initial coarse Sn particles with sizes of 3-30 μm are converted to SnO2 nanocrystals (approximately 4 nm) while GO is reduced to graphene. Composite with different grinding times (1 h 20 min, 2 h 20 min or 8 h 20 min, abbreviated to 1, 2 or 8 h below) and raw material ratios (Sn:GO, 1:2, 1:1, 2:1, w/w) are investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and transmission electron microscopy. The as-prepared SnO2 /graphene composite with a grinding time of 8 h and raw material ratio of 1:1 forms micrometer-sized architected chips composed of composite sheets, and demonstrates a high tap density of 1.53 g cm(-3). By using such composites as anode material for LIBs, a high specific capacity of 891 mA h g(-1) is achieved even after 50 cycles at 100 mA g(-1). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly reddened Type Ia supernova SN 2004ab: another case of anomalous extinction

Science.gov (United States)

Chakradhari, N. K.; Sahu, D. K.; Anupama, G. C.; Prabhu, T. P.

2018-02-01

We present optical photometric and spectroscopic data for supernova SN 2004ab, a highly reddened normal Type Ia supernova. The total reddening is estimated as E(B - V) = 1.70 ± 0.05 mag. The intrinsic decline-rate parameter Δm15(B)true is 1.27 ± 0.05, and the B-band absolute magnitude at maximum MB^{max} is -19.31 ± 0.25 mag. The host galaxy NGC 5054 is found to exhibit anomalous extinction with a very low value of RV = 1.41 ± 0.06 in the direction of SN 2004ab. The peak bolometric luminosity is derived as log L_bol^max = 43.10 ± 0.07 erg s-1. The photospheric velocity measured from the absorption minimum of the Si II λ6355 line shows a velocity gradient of \\dot{v} = 90 km s-1 d-1, indicating that SN 2004ab is a member of the high velocity gradient (HVG) subgroup. The ratio of the strengths of the Si II λ5972 and λ6355 absorption lines, R(Si II), is estimated as 0.37, while their pseudo-equivalent widths suggest that SN 2004ab belongs to the broad line (BL) type subgroup.

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.

Ultrasmall SnO2 Nanocrystals: Hot-bubbling Synthesis, Encapsulation in Carbon Layers and Applications in High Capacity Li-Ion Storage

Science.gov (United States)

Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R.; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G.; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G.

2014-04-01

Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA.h.g-1 at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs.

Sudden flux change studies in high field superconducting accelerator magnets

International Nuclear Information System (INIS)

Feher, S.; Bordini, B.; Carcagno, R.; Makulski, A.; Orris, D.F.; Pischalnikov, Y.M.; Sylvester, C.; Tartaglia, M.; Tompkins, J.C.; Zlobin, A.V.

2004-01-01

As part of the High Field Magnet Program at Fermilab many magnets have been tested which utilize multi strand Rutherford type cable made of state-of-the art Nb 3 Sn strands. During these magnet tests we observed sudden flux changes by monitoring coil voltages and the magnetic field close to the magnets. These flux changes might be linked to magnet instabilities. The voltage spike signals were correlated with quench antenna signals, a strong indication that these are magnet phenomena. With a new high resolution voltage spike detection system, we were able to observe the detailed structure of the spikes. Two fundamentally different signal shapes were distinguished, most likely generated by different mechanisms

Sn buffered by shape memory effect of NiTi alloys as high-performance anodes for lithium ion batteries

International Nuclear Information System (INIS)

Hu Renzong; Zhu Min; Wang Hui; Liu Jiangwen; Liuzhang Ouyang; Zou Jin

2012-01-01

By applying the shape memory effect of the NiTi alloys to buffer the Sn anodes, we demonstrate a simple approach to overcome a long-standing challenge of Sn anode in the applications of Li-ion batteries – the capacity decay. By supporting the Sn anodes with NiTi shape memory alloys, the large volume change of Sn anodes due to lithiation and delithiation can be effectively accommodated, based on the stress-induced martensitic transformation and superelastic recovery of the NiTi matrix respectively, which leads to a decrease in the internal stress and closing of cracks in Sn anodes. Accordingly, stable cycleability (630 mA h g −1 after 100 cycles at 0.7C) and excellent high-rate capabilities (478 mA h g −1 at 6.7C) were attained with the NiTi/Sn/NiTi film electrode. These shape memory alloys can also combine with other high-capacity metallic anodes, such as Si, Sb, Al, and improve their cycle performance.

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

Science.gov (United States)

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

2012-09-01

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

A facile hydrothermal strategy for synthesis of SnO2 nanorods-graphene nanocomposites for high performance photocatalysis.

Science.gov (United States)

Chen, Lu-Ya; Zhang, Wei-De; Xu, Bin; Yu, Yu-Xiang

2012-09-01

In this study, we report a facilely hydrothermal process for synthesizing SnO2 nanorods-graphene (SnO2 nanorods-GR) composite using graphite oxide and SnCl4 as raw materials. The SnO2 nanorods-GR composite was characterized by X-ray diffraction, electron microscopy, Xray photoelectron spectroscopy, and thermogravimetric analysis. Compared to commercial TiO2 nanoparticles P25 and neat SnO2 nanorods, the SnO2 nanorods-GR composite exhibits higher photocatalytic activity under UV light irradiation. The mechanism of its high photocatalytic activity is mainly ascribed to the synergy effect between SnO2 and graphene, in which graphene acts as an adsorbent and electron acceptor due to its large structure of pi-pi conjugation from sp2 hybrid carbon atoms. The results demonstrated in this study provide a promising way to enhance the photocatalytic activity by compounding semiconductive nanocrystals with graphene.

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

International Nuclear Information System (INIS)

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

1991-01-01

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

Extremely large magnetoresistance and Kohler's rule in PdSn4: A complete study of thermodynamic, transport, and band-structure properties

Science.gov (United States)

Jo, Na Hyun; Wu, Yun; Wang, Lin-Lin; Orth, Peter P.; Downing, Savannah S.; Manni, Soham; Mou, Dixiang; Johnson, Duane D.; Kaminski, Adam; Bud'ko, Sergey L.; Canfield, Paul C.

2017-10-01

The recently discovered material PtSn4 is known to exhibit extremely large magnetoresistance (XMR) that also manifests Dirac arc nodes on the surface. PdSn4 is isostructural to PtSn4 with the same electron count. We report on the physical properties of high-quality single crystals of PdSn4 including specific heat, temperature- and magnetic-field-dependent resistivity and magnetization, and electronic band-structure properties obtained from angle-resolved photoemission spectroscopy (ARPES). We observe that PdSn4 has physical properties that are qualitatively similar to those of PtSn4, but find also pronounced differences. Importantly, the Dirac arc node surface state of PtSn4 is gapped out for PdSn4. By comparing these similar compounds, we address the origin of the extremely large magnetoresistance in PdSn4 and PtSn4; based on detailed analysis of the magnetoresistivity ρ (H ,T ) , we conclude that neither the carrier compensation nor the Dirac arc node surface state are the primary reason for the extremely large magnetoresistance. On the other hand, we find that, surprisingly, Kohler's rule scaling of the magnetoresistance, which describes a self-similarity of the field-induced orbital electronic motion across different length scales and is derived for a simple electronic response of metals to an applied magnetic field is obeyed over the full range of temperatures and field strengths that we explore.

Synthesis, Characterization, and Photocatalytic Activity of Zn-Doped SnO2/Zn2SnO4 Coupled Nanocomposites

Directory of Open Access Journals (Sweden)

Tiekun Jia

2014-01-01

Full Text Available Zn-doped SnO2/Zn2SnO4 nanocomposites were prepared via a two-step hydrothermal synthesis method. The as-prepared samples were characterized by X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, UV-vis diffuse reflection spectroscopy, and adsorption-desorption isotherms. The results of FESEM and TEM showed that the as-prepared Zn-doped SnO2/Zn2SnO4 nanocomposites are composed of numerous nanoparticles with the size ranging from 20 nm to 50 nm. The specific surface area of the as-prepared Zn-doped SnO2/Zn2SnO4 nanocomposites is estimated to be 71.53 m2/g by the Brunauer-Emmett-Teller (BET method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB, and the resulting showed that Zn-doped SnO2/Zn2SnO4 nanocomposites exhibited excellent photocatalytic activity due to their higher specific surface area and surface charge carrier transfer.

Amorphous Ultrathin SnO2 Films by Atomic Layer Deposition on Graphene Network as Highly Stable Anodes for Lithium-Ion Batteries.

Science.gov (United States)

Xie, Ming; Sun, Xiang; George, Steven M; Zhou, Changgong; Lian, Jie; Zhou, Yun

2015-12-23

Amorphous SnO2 (a-SnO2) thin films were conformally coated onto the surface of reduced graphene oxide (G) using atomic layer deposition (ALD). The electrochemical characteristics of the a-SnO2/G nanocomposites were then determined using cyclic voltammetry and galvanostatic charge/discharge curves. Because the SnO2 ALD films were ultrathin and amorphous, the impact of the large volume expansion of SnO2 upon cycling was greatly reduced. With as few as five formation cycles best reported in the literature, a-SnO2/G nanocomposites reached stable capacities of 800 mAh g(-1) at 100 mA g(-1) and 450 mAh g(-1) at 1000 mA g(-1). The capacity from a-SnO2 is higher than the bulk theoretical values. The extra capacity is attributed to additional interfacial charge storage resulting from the high surface area of the a-SnO2/G nanocomposites. These results demonstrate that metal oxide ALD on high surface area conducting carbon substrates can be used to fabricate high power and high capacity electrode materials for lithium-ion batteries.

Structural and electrochemical properties of SnO nanoflowers as an anode material for lithium ion batteries

International Nuclear Information System (INIS)

Iqbal, M. Zubair; Wang, Fengping; Zhao, Hailei; Rafique, M. Yasir; Wang, Jie; Li, Quanshui

2012-01-01

Graphical abstract: -- Novel self-assembled highly hierarchical SnO nanoflowers with acute edge petals have been successfully synthesized by a template-free hydrothermal growth method using SnCl 2 ·2H 2 O and KOH as precursors. Field emission scanning electron microscopy results show that the flower-like SnO architectureis in the range 4–7 μm. Furthermore, Raman modes at A 1g = 212 and B 1g = 114 cm −1 further testify to the existence of nanotetragonal phase SnO. The electrochemical results suggest that synthesized SnO nanoflowers are a promising anode material for lithium ion batteries.

Ultrasmall SnO2 Nanocrystals: Hot-bubbling Synthesis, Encapsulation in Carbon Layers and Applications in High Capacity Li-Ion Storage

Science.gov (United States)

Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R.; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G.; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G.

2014-01-01

Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA·h·g−1 at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs. PMID:24732294

Fabrication and component testing results for a Nb3Sn dipole magnet

International Nuclear Information System (INIS)

Dell'Orco, D.; Scanlan, R.M.; Taylor, C.E.; Lietzke, A.; Caspi, S.; van Oort, J.M.; McInturff, A.D.

1994-10-01

At present, the maximum field achieved in accelerator R ampersand D dipoles is slightly over 10T, with NbTi conductor at 1.8 K. Although Nb 3 Sn has the potential to achieve much higher fields, none of the previous dipoles constructed from Nb 3 Sn have broken the 10T barrier. We report here on the construction of a dipole with high current density Nb 3 Sn with a predicted short sample limit of 13T. A wind and react technique, followed by epoxy impregnation of the fiberglass insulated coils, was used. The problems identified with the use of Nb 3 SD in earlier dipole magnets were investigated in a series of supplemental tests. This includes measurement of the degradation of J c with transverse strain, cabling degradation, joint resistance measurements, and epoxy strength tests. In addition, coff assembly techniques were developed to ensure that adequate prestress could be applied without damaging the reacted Nb 3 Sn cable. We report here the results of these tests and the construction status of this 50 mm bore dipole

Cable testing for Fermilab's high field magnets using small racetrack coils

International Nuclear Information System (INIS)

Feher, S.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bordini, B.; Bossert, R.; Carcagno, R.; Kashikhin, V.I.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Orris, D.; Pischalnikov, Y.; Sylvester, C.; Tartaglia, M.; Yamada, R.; Zlobin, A.V.

2004-01-01

As part of the High Field Magnet program at Fermilab simple magnets have been designed utilizing small racetrack coils based on a sound mechanical structure and bladder technique developed by LBNL. Two of these magnets have been built in order to test Nb 3 Sn cables used in cos-theta dipole models. The powder-in-tube strand based cable exhibited excellent performance. It reached its critical current limit within 14 quenches. Modified jelly roll strand based cable performance was limited by magnetic instabilities at low fields as previously tested dipole models which used similar cable

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.

PROTEUS-SN User Manual

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-16

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

Production of Sn/SnO2/MWCNT composites by plasma oxidation after thermal evaporation from pure Sn targets onto buckypapers.

Science.gov (United States)

Alaf, M; Gultekin, D; Akbulut, H

2012-12-01

In this study, tin/tinoxide/multi oxide/multi walled carbon nano tube (Sn/SnO2/MWCNT) composites were produced by thermal evaporation and then subsequent plasma oxidation. Buckypapers having controlled porosity were prepared by vacuum filtration from functionalized MWCNTs. Pure metallic tin was thermally evaporated on the buckypapers in argon atmosphere with different thicknesses. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypaper to form a nanocomposite. The tin/MWCNT composites were subjected to plasma oxidation process at oxygen/argon gas mixture. Three different plasma oxidation times (30, 45 and 60 minutes) were used to investigate oxidation and physical and microstructural properties. The effect of coating thickness and oxidation time was investigated to understand the effect of process parameters on the Sn and SnO2 phases after plasma oxidation. Quantitative phase analysis was performed in order to determine the relative phase amounts. The structural properties were studied by field-emission gun scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD).

Stress effects on multifilamentary Nb3Sn wire

International Nuclear Information System (INIS)

Bartlett, R.J.; Taylor, R.D.; Thompson, J.D.

1979-01-01

Critical current I/sub c/ measurements were obtained on highly stabilized mf Nb 3 Sn wires as a function of heat treatment, stress, temperature, and applied magnetic field. The ratio of the area of the copper to bronze core-niobium tube is about 8, and the filaments are concentrated in the inner 30% of the wire cross section. Values of I/sub c/ and T/sub c/ were determined for samples subjected to a wide range of heat treatments. Diffusion reaction times and temperatures in the ranges 16 to 128 hr and 700 to 750 0 C provided a number of mf Nb 3 Sn wires having similar I/sub c/ characteristics. To some extent the residual compressive loading on the Nb 3 Sn wires varied with the particular heat treatment. This loading arises primarily from the differential contraction of the remaining bronze and the Nb 3 Sn layer when cooled from the reaction temperature to the operating temperature. It was found that, by controlled bending or stretching of the wires, whereby some of the strain in the Nb 3 Sn is relieved, the I/sub c/ at 14 K is increased by as much as 30% and the critical temperature is increased by up to 1 K

Field Quality Study of a 1-m-Long Single-Aperture 11-T Nb$_3$Sn Dipole Model for LHC Upgrades

Energy Technology Data Exchange (ETDEWEB)

Chlachidze, G. [Fermilab; DiMarco, J. [Fermilab; Andreev, N. [Fermilab; Apollinari, G. [Fermilab; Auchmann, B. [CERN; Barzi, E. [Fermilab; Bossert, R. [Fermilab; Fiscarelli, L. [CERN; Karppinen, M. [CERN; Nobrega, F. [Fermilab; Novitski, I. [Fermilab; Rossi, L. [CERN; Smekens, D. [CERN; Turrioni, D. [Fermilab; Velev, G. V. [Fermilab; Zlobin, A. V. [Fermilab

2014-01-01

FNAL and CERN are carrying out a joint R&D program with the goal of building a 5.5-m-long twin-aperture 11-T Nb_3Sn dipole prototype that is suitable for installation in the LHC. An important part of the program is the development and test of a series of short single-aperture and twin-aperture dipole models with a nominal field of 11 T at the LHC operation current of 11.85 kA and 20% margin. This paper presents the results of magnetic measurements of a 1-m-long single-aperture Nb_3Sn dipole model fabricated and tested recently at FNAL, including geometrical field harmonics and effects of coil magnetization and iron yoke saturation.

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

Controllable synthesis of Au@SnO2 core-shell nanohybrids with enhanced photocatalytic activities

Science.gov (United States)

Zhang, Shaofeng; Hao, Jinggang; Ren, Feng; Wu, Wei; Xiao, Xiangheng

2017-05-01

Combination of semiconductors with plasmonic nanostructures is an effective route to promote the solar light harvesting as well as the efficiency of photocatalysis. In the present work, the Au@SnO2 hybrid nanostructures with Au nanorods as the cores and highly crystallized SnO2 nanoparticles as the shells were fabricated by a facile hydrothermal method. A critical factor, which influences the coating state of the SnO2 shells over Au NRs, was found to be the concentration of CTAB agent in the system and the corresponding mechanism was also proposed. The photocatalytic activities of the Au@SnO2 nanohybrids were examined by degradation of rhodamine B (RhB) dyes at room temperature. The Au@SnO2 nanohybrids exhibited much higher catalytic activities than that of the commercial SnO2 NPs, which could be attributed to the localized electric field enhancement effect of Au nanorods plasmon and charges transfer between the Au nanorods and SnO2.

Advances in development of Nb_{3}Sn superconducting radio-frequency cavities

Directory of Open Access Journals (Sweden)

Sam Posen

2014-11-01

Full Text Available A 1.3 GHz Nb_{3}Sn superconducting radio-frequency cavity prepared with a modified annealing step reached B_{pk}>50  mT, well above B_{c1}=25±7  mT, without the strong Q-slope observed in previous Nb_{3}Sn cavities. At 4.2 K, it has a Q_{0} of approximately 1×10^{10} at >10  MV/m, far outperforming Nb at useable gradients. At 2 K, quench occurred at ∼55  mT, apparently due to a defect, so additional treatment may increase the maximum gradient. Material parameters of the coating were extracted from Q vs T data, including a T_{c} of 18.0±0.1  K, close to the maximum literature value. High power pulses were used to reach fields far higher than in CW measurements, and near T_{c}, quench fields close to the superheating field were observed. Based on a review of previous experience with Nb_{3}Sn cavities, a speculative mechanism involving weak link grain boundaries is presented to explain how the modified annealing step could be the cause of the absence of strong Q-slope. Finally, an analysis of the progress to date provides hints that the path forward for Nb_{3}Sn cavities should focus on minimizing defects.

Intergrown SnO{sub 2}–TiO{sub 2}@graphene ternary composite as high-performance lithium-ion battery anodes

Energy Technology Data Exchange (ETDEWEB)

Jiao, Zheng; Gao, Renmei [Shanghai University, Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering (China); Tao, Haihua [Inspection Center of Industrial Products and Raw Materials of SHCIQ (China); Yuan, Shuai [Shanghai University, Research Center of Nanoscience and Nanotechnology (China); Xu, Laiqiang; Xia, Saisai; Zhang, Haijiao, E-mail: hjzhang128@shu.edu.cn [Shanghai University, Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering (China)

2016-10-15

In recent years, a lot of metal oxides with high theoretical capacity have widely investigated as the high-performance anode materials for lithium-ion batteries (LIBs). In this work, a simple, facile and effective one-pot hydrothermal strategy toward ternary SnO{sub 2}–TiO{sub 2}@graphene composite has been developed by using SnCl{sub 2} and TiOSO{sub 4} as the starting materials. The obtained composite demonstrates a unique structure and high surface areas, in which both SnO{sub 2} and TiO{sub 2} nanoparticles are well grown on the surface of graphene. More interestingly, the SnO{sub 2} and TiO{sub 2} nanoparticles are intergrowth together, totally different with the traditional ternary hybrids. When used as anode material for LIBs, the introduction of TiO{sub 2} plays a crucial role in maintaining the structural stability of the electrode during Li{sup +} insertion/extraction, which can effectively prevent the aggregation of SnO{sub 2} nanoparticles. The electrochemical tests indicate that as-prepared SnO{sub 2}–TiO{sub 2}@graphene composite exhibits a high capacity of 1276 mA h g{sup −1} after 200 cycles at the current density of 200 mA g{sup −1}. Furthermore, the composite also maintains the specific capacity of 611 mA h g{sup −1} at an ultrahigh current density of 2000 mA g{sup −1}, which is superior to those of the reported SnO{sub 2} and SnO{sub 2}/graphene hybrids. Accordingly, the remarkable electrochemical performance of ternary SnO{sub 2}–TiO{sub 2}@graphene composites is mainly attributed to their unique nanostructure, high surface areas, and the synergistic effect not only between graphene and metal oxides but also between the intergrown SnO{sub 2} and TiO{sub 2} nanoparticles.Graphical abstractIntergrown SnO{sub 2} and TiO{sub 2} nanoparticles have been successfully anchored onto the graphene nanosheets as high-performance lithium-ion battery anodes.

Mesoporous Zn2SnO4 as effective electron transport materials for high-performance perovskite solar cells

International Nuclear Information System (INIS)

Bao, Sha; Wu, Jihuai; He, Xin; Tu, Yongguang; Wang, Shibo; Huang, Miaoliang; Lan, Zhang

2017-01-01

Highlights: •Large grain and mesoporous Zn 2 SnO 4 are synthesized by a facile hydrothermal method. •Perovskite device with Zn 2 SnO 4 electron transport layer get efficiency of 17.21%. •While the device with TiO 2 electron transport layer obtain an efficiency of 14.83%. •Superior photovoltaic performance stems from the intrinsic characteristics of Zn 2 SnO 4 . -- Abstract: Electron transport layer with higher carrier mobility and suitable band gap structure plays a significant role in determining the photovoltaic performance of perovskite solar cells (PSCs). Here, we report a synthesis of high crystalline zinc stannate (Zn 2 SnO 4 ) by a facile hydrothermal method. The as-synthesized Zn 2 SnO 4 possesses particle size of 20 nm, large surface area, mesoporous hierarchical structure, and can be used as a promising electron-transport materials to replace the conventional mesoporous TiO 2 material. A perovskite solar cell with structure of FTO/blocking layer/Zn 2 SnO 4 /CH 3 NH 3 PbI 3 /Spiro-OMeOTAD/Au is fabricated, and the preparation condition is optimized. The champion device based on Zn 2 SnO 4 electron transport material achieves a power conversion efficiency of 17.21%, while the device based on TiO 2 electron transport material gets an efficiency of 14.83% under the same experimental conditions. The results render Zn 2 SnO 4 an effective candidate as electron transport material for high performance perovskite solar cells and other devices.

Upcoversion performance improvement of NaYF4:Yb, Er by Sn codoping: Enhanced emission intensity and reduced decay time

International Nuclear Information System (INIS)

Yu, Han; Cao, Wenbing; Huang, Qingming; Ma, En; Zhang, Xinqi; Yu, Jianchang

2013-01-01

In this manuscript we report a phenomenon that upconversion emission intensity of Er 3+ was enhanced while decay time constant was decreased obviously by Sn codoping with Yb/Er into hexagonal NaYF 4 synchronously. X-ray powder diffiraction, field emission scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin-resonance spectroscopy and upconversion emission spectra were employed to explore the relation of crystal structure and properties. From these characterizations we found that symmetry of the rare earth ion local crystal field could be tuned by different Sn codoping concentration. For the variable valence property of Sn the local crystal field asymmetry and emission intensity of NaYF 4 :Yb, Er arrived to the maximum when 3 mol% Sn was codoped, while decay time was reduced. The study of this changing tends of upconversion emission intensity and decay time constant may be helpful for design and fabrication of high performance upconversion materials. - Graphical abstract: Variable-valenced Sn is introduced with Yb/Er into NaFY 4 to tune structure and local crystal field. Upconversion emission intensity of Er 3+ was enhanced while decay time constant was decreased. Display Omitted - Highlights: • NaYF 4 : Yb, Er was codoped with different concentration Sn. • Upconversion emission intensity was enhanced while decay time constant was decreased. • Introduction of variable-valenced Sn is effective to tune structure and crystal field of NaFY 4

Controlling the Sn-C bonds content in SnO2@CNTs composite to form in situ pulverized structure for enhanced electrochemical kinetics.

Science.gov (United States)

Cheng, Yayi; Huang, Jianfeng; Qi, Hui; Cao, Liyun; Luo, Xiaomin; Li, Jiayin; Xu, Zhanwei; Yang, Jun

2017-12-07

The Sn-C bonding content between the SnO 2 and CNTs interface was controlled by the hydrothermal method and subsequent heat treatment. Electrochemical analysis found that the SnO 2 @CNTs with high Sn-C bonding content exhibited much higher capacity contribution from alloying and conversion reaction compared with the low content of Sn-C bonding even after 200 cycles. The high Sn-C bonding content enabled the SnO 2 nanoparticles to stabilize on the CNTs surface, realizing an in situ pulverization process of SnO 2 . The in situ pulverized structure was beneficial to maintain the close electrochemical contact of the working electrode during the long-term cycling and provide ultrafast transfer paths for lithium ions and electrons, which promoted the alloying and conversion reaction kinetics greatly. Therefore, the SnO 2 @CNTs composite with high Sn-C bonding content displayed highly reversible alloying and conversion reaction. It is believed that the composite could be used as a reference for design chemically bonded metal oxide/carbon composite anode materials in lithium-ion batteries.

High Field Magnet R and D in the USA

International Nuclear Information System (INIS)

Gourlay, S.A.

2003-01-01

Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb 3 Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed.

High Field Magnet R and D in the USA

International Nuclear Information System (INIS)

Gourlay, Stephen A.

2003-01-01

Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb 3 Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed

Preliminary proposal of a Nb3Sn quadrupole model for the low β insertions of the LHC

International Nuclear Information System (INIS)

Ambrosio, G.; Ametrano, F.; Bellomo, G.; Broggi, F.; Rossi, L.; Volpini, G.

1995-09-01

In recent years Nb 3 Sn based conductors have shown wide applicability for superconducting magnets in many research areas like high field solenoids for laboratory experiment, for NMR spectroscopy and high field magnets for fusion. Nb 3 Sn technology is progressing fast, increasing both technical reliability and availability. The Nb 3 Sn technology, which has a higher critical field than NbTi, seems attractive for IR (Insertion Region) quadrupoles of large colliders . In this paper it is proposed the construction of a superconducting quadrupole wound with Nb 3 Sn cable for a second generation IR inner triplet low β quadrupoles, for the Large Hadron Collider at CERN. The low β quadrupoles, control the beam focusing at collision points, therefore a gain in term of focus strength and/or coil aperture can increase significantly machine performance. Two are the main steps for the whole project: 1) design and construction of a 1 metre long quadrupole to demonstrate the actual feasibility, which is the subject of this proposal; 2) study for integration of the quadrupole in the machine and final design of 5 m long quadrupoles finalized to the LHC

Energy dissipation of composite multifilamentary superconductors for high-current ramp-field magnet applications

International Nuclear Information System (INIS)

Gung, C.Y.

1993-01-01

Energy dissipation, which is also called AC loss, of a composite multifilamentary superconducting wire is one of the most fundamental concerns in building a stable superconducting magnet. Characterization and reduction of AC losses are especially important in designing a superconducting magnet for generating transient magnetic fields. The goal of this thesis is to improve the understanding of AC-loss properties of superconducting wires developed for high-current ramp-field magnet applications. The major tasks include: (1) building an advanced AC-loss measurement system, (2) measuring AC losses of superconducting wires under simulated pulse magnet operations, (3) developing an analytical model for explaining the new AC-loss properties found in the experiment, and (4) developing a computational methodology for comparing AC losses of a superconducting wire with those of a cable for a superconducting pulse magnet. A new experimental system using an isothermal calorimetric method was designed and constructed to measure the absolute AC losses in a composite superconductor. This unique experimental setup is capable of measuring AC losses of a brittle Nb 3 Sn wire carrying high AC current in-phase with a large-amplitude pulse magnetic field. Improvements of the accuracy and the efficiency of this method are discussed. Three different types of composite wire have been measured: a Nb 3 Sn modified jelly-roll (MJR) internal-tin wire used in a prototype ohmic heating coil, a Nb 3 Sn internal-tin wire developed for a fusion reactor ohmic heating coil, and a NbTi wire developed for the magnets in a particle accelerator. The cross sectional constructions of these wires represent typical commercial wires manufactured for pulse magnet applications

Nanocrystalline SnO2 thin films: Structural, morphological, electrical transport and optical studies

International Nuclear Information System (INIS)

Sakhare, R.D.; Khuspe, G.D.; Navale, S.T.; Mulik, R.N.; Chougule, M.A.; Pawar, R.C.; Lee, C.S.; Sen, Shashwati; Patil, V.B.

2013-01-01

Highlights: ► Novel chemical route of synthesis of SnO 2 films. ► Physical properties SnO 2 are influenced by process temperature. ► The room temperature electrical conductivity of SnO 2 is of 10 −7 –10 −5 (Ω cm) −1 . ► SnO 2 exhibit high absorption coefficient (10 4 cm −1 ). -- Abstract: Sol–gel spin coating method has been successfully employed for preparation of nanocrystalline tin oxide (SnO 2 ) thin films. The effect of processing temperature on the structure, morphology, electrical conductivity, thermoelectric power and band gap was studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction pattern, atomic force microscopy, two probe technique and UV–visible spectroscopy. X-ray diffraction (XRD) analysis showed that SnO 2 films are crystallized in the tetragonal phase and present a random orientation. Field emission scanning electron microscopy (FESEM) analysis revealed that surface morphology of the tin oxide film consists nanocrystalline grains with uniform coverage of the substrate surface. Transmission electron microscopy (TEM) of SnO 2 film showed nanocrystals having diameter ranging from 5 to 10 nm. Selected area electron diffraction (SAED) pattern confirms tetragonal phase evolution of SnO 2 . Atomic force microscopy (AFM) analysis showed surface morphology of SnO 2 film is smooth. The dc electrical conductivity showed the semiconducting nature with room temperature electrical conductivity increased from 10 −7 to 10 −5 (Ω cm) −1 as processing temperature increased from 400 to 700 °C. Thermo power measurement confirms n-type conduction. The band gap energy of SnO 2 film decreased from 3.88 to 3.60 eV as processing temperature increased from 400 to 700 °C

Advantage and Challenges of $Nb_3Sn$ Superconducting Undulators

Energy Technology Data Exchange (ETDEWEB)

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

2018-04-01

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

Experimental investigation of the ternary system Ni–Pd–Sn with special focus on the B8-type phase

International Nuclear Information System (INIS)

Jandl, Isabella; Ipser, Herbert; Richter, Klaus W.

2015-01-01

The ternary alloy system Ni–Pd–Sn was investigated experimentally from 700 °C upwards, with special focus on the general NiAs-type compounds. The phase diagram and crystallographic parameters were studied by means of powder X-ray diffraction (XRD), differential thermal analysis (DTA), light optical microscopy (LOM) and scanning electron microscopy (SEM) in combination with energy dispersive X-ray spectroscopy (EDX). An isothermal section at 700 °C was constructed wherein a continuous phase field between the binary NiAs-type compounds γ (PdSn) and Ni 3 Sn 2 (high temperature modification) was detected. A series of samples throughout this phase field was used to investigate lattice parameter variations, occupation of the atomic sites and the melting behaviour. A partial ordering of the transition metals was observed. Moreover, three vertical sections at 30 at.%, 40 at.% and 50 at.% Sn were determined. Altogether, seven ternary invariant phase reactions were discovered: two ternary eutectic reactions, one ternary eutectoid reaction, three ternary transition reactions and one maximum. A complete reaction scheme for the investigated temperature range is given. Furthermore, a partial liquidus surface projection, except for the low-temperature Sn-rich region, was developed. - Highlights: • Detailed study of the ternary alloy system Ni–Pd–Sn. • 1 Isotherm, 3 vertical sections, a partial liquidus projection and a reaction scheme. • A continuous phase field, between γ and Ni 3 Sn 2 , was discovered. • Lattice parameters and structural features in this phase field were analysed. • A partial order of Ni and Pd in this phase field was observed

Gamma-ray observations of SN 1987A with an array of high-purity germanium detectors

International Nuclear Information System (INIS)

Sandie, W.G.; Nakano, G.H.; Chase, L.F. Jr.; Fishman, G.J.; Meegan, C.A.; Wilson, R.B.; Paciesas, W.

1988-01-01

A balloon borne gamma-ray spectrometer comprising an array of high-purity n-type germanium (HPGe) detectors having geometric area 119 cm 2 , resolution 2.5 keV at 1.0 MeV, surrounded by an active NaI (Tl) collimator and Compton suppressing anticoincidence shield nominally 10 cm thick, was flown from Alice Springs, Northern Territory, Australia, on May 29--30, 1987, 96 days after the observed neutrino pulse. The average column depth of residual atmosphere in the direction of SN 1987A at float altitude was 6.3 g cm-2 during the observation. SN 1987A was within the 22-deg full-width-half-maximum (FWHM) field of view for about 3300 s during May 29.9--30.3 UT. No excess gamma rays were observed at energies appropriate to the Ni(56)-Co(56) decay chain or from other lines in the energy region from 0.1 to 3.0 MeV. With 80% of the data analyzed, the 3-sigma upper limit obtained for the 1238-keV line from Co(56) at the instrument resolution (about 3 keV) is 1.3 x 10-3 photons cm-2 s-1

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Designing a New Ni-Mn-Sn Ferromagnetic Shape Memory Alloy with Excellent Performance by Cu Addition

Directory of Open Access Journals (Sweden)

Kun Zhang

2018-02-01

Full Text Available Both magnetic-field-induced reverse martensitic transformation (MFIRMT and a high working temperature are crucial for the application of Ni-Mn-Sn magnetic shape memory alloys. Here, by first-principles calculations, we demonstrate that the substitution of Cu for Sn is effective not only in enhancing the MFIRMT but also in increasing martensitic transformation, which is advantageous for its application. Large magnetization difference (ΔM in Ni-Mn-Sn alloy is achieved by Cu doping, which arises from the enhancement of magnetization of austenite due to the change of Mn-Mn interaction from anti-ferromagnetism to ferromagnetism. This directly leads to the enhancement of MFIRMT. Meanwhile, the martensitic transformation shifts to higher temperature, owing to the energy difference between the austenite L21 structure and the tetragonal martensite L10 structure increases by Cu doping. The results provide the theoretical data and the direction for developing a high temperature magnetic-field-induced shape memory alloy with large ΔM in the Ni-Mn-Sn Heusler alloy system.

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.

Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

Directory of Open Access Journals (Sweden)

R. Nurzulaikha

2015-09-01

Full Text Available A graphene-tin oxide (G-SnO2 nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM, high resolution transmission electron microscope (HRTEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS. A homogeneous deposition of SnO2 nanoparticles with an average particle size of 10 nm on the graphene was observed in the FESEM and HRTEM images. The G-SnO2 nanocomposite was used to fabricate a modified electrode for the electrochemical detection of dopamine (DA in the presence of ascorbic acid (AA. Differential pulse voltammetry (DPV showed a limit of detection (LoD of 1 μM (S/N = 3 in the presence of ascorbic acid (AA. Keywords: Graphene, Tin oxide, Nanocomposite, Electrochemical sensor, Biosensor, Dopamine

Synthesis And Electrochemical Characteristics Of Mechanically Alloyed Anode Materials SnS2 For Li/SnS2 Cells

Directory of Open Access Journals (Sweden)

Hong J.H.

2015-06-01

Full Text Available With the increasing demand for efficient and economic energy storage, tin disulfide (SnS2, as one of the most attractive anode candidates for the next generation high-energy rechargeable Li-ion battery, have been paid more and more attention because of its high theoretical energy density and cost effectiveness. In this study, a new, simple and effective process, mechanical alloying (MA, has been developed for preparing fine anode material tin disulfides, in which ammonium chloride (AC, referred to as process control agents (PCAs, were used to prevent excessive cold-welding and accelerate the synthesis rates to some extent. Meanwhile, in order to decrease the mean size of SnS2 powder particles and improve the contact areas between the active materials, wet milling process was also conducted with normal hexane (NH as a solvent PCA. The prepared powders were both characterized by X-ray diffraction, Field emission-scanning electron microscopeand particle size analyzer. Finally, electrochemical measurements for Li/SnS2 cells were takenat room temperature, using a two-electrode cell assembled in an argon-filled glove box and the electrolyte of 1M LiPF6 in a mixture of ethylene carbonate(EC/dimethylcarbonate (DMC/ethylene methyl carbonate (EMC (volume ratio of 1:1:1.

Extremely large magnetoresistance and Kohler's rule in PdSn4 : A complete study of thermodynamic, transport, and band-structure properties

International Nuclear Information System (INIS)

Jo, Na Hyun; Wu, Yun; Wang, Lin-Lin; Orth, Peter P.; Downing, Savannah S.

2017-01-01

The recently discovered material PtSn 4 is known to exhibit extremely large magnetoresistance (XMR) that also manifests Dirac arc nodes on the surface. PdSn 4 is isostructural to PtSn 4 with the same electron count. Here, we report on the physical properties of high-quality single crystals of PdSn 4 including specific heat, temperature- and magnetic-field-dependent resistivity and magnetization, and electronic band-structure properties obtained from angle-resolved photoemission spectroscopy (ARPES). We observe that PdSn 4 has physical properties that are qualitatively similar to those of PtSn 4 , but find also pronounced differences. Importantly, the Dirac arc node surface state of PtSn 4 is gapped out for PdSn 4 . By comparing these similar compounds, we address the origin of the extremely large magnetoresistance in PdSn 4 and PtSn 4 ; based on detailed analysis of the magnetoresistivity ρ (H , T) , we conclude that neither the carrier compensation nor the Dirac arc node surface state are the primary reason for the extremely large magnetoresistance. On the other hand, we also find that, surprisingly, Kohler's rule scaling of the magnetoresistance, which describes a self-similarity of the field-induced orbital electronic motion across different length scales and is derived for a simple electronic response of metals to an applied magnetic field is obeyed over the full range of temperatures and field strengths that we explore.

Upcoversion performance improvement of NaYF{sub 4}:Yb, Er by Sn codoping: Enhanced emission intensity and reduced decay time

Energy Technology Data Exchange (ETDEWEB)

Yu, Han, E-mail: fjfzyh@fzu.edu.cn [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China); Cao, Wenbing [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China); Huang, Qingming [Instrumentation Analysis and Research Center, Fuzhou University, Fuzhou, Fujian 350002 (China); Ma, En [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Zhang, Xinqi [Instrumentation Analysis and Research Center, Fuzhou University, Fuzhou, Fujian 350002 (China); Yu, Jianchang [College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108 (China)

2013-11-15

In this manuscript we report a phenomenon that upconversion emission intensity of Er{sup 3+} was enhanced while decay time constant was decreased obviously by Sn codoping with Yb/Er into hexagonal NaYF{sub 4} synchronously. X-ray powder diffiraction, field emission scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin-resonance spectroscopy and upconversion emission spectra were employed to explore the relation of crystal structure and properties. From these characterizations we found that symmetry of the rare earth ion local crystal field could be tuned by different Sn codoping concentration. For the variable valence property of Sn the local crystal field asymmetry and emission intensity of NaYF{sub 4}:Yb, Er arrived to the maximum when 3 mol% Sn was codoped, while decay time was reduced. The study of this changing tends of upconversion emission intensity and decay time constant may be helpful for design and fabrication of high performance upconversion materials. - Graphical abstract: Variable-valenced Sn is introduced with Yb/Er into NaFY{sub 4} to tune structure and local crystal field. Upconversion emission intensity of Er{sup 3+} was enhanced while decay time constant was decreased. Display Omitted - Highlights: • NaYF{sub 4}: Yb, Er was codoped with different concentration Sn. • Upconversion emission intensity was enhanced while decay time constant was decreased. • Introduction of variable-valenced Sn is effective to tune structure and crystal field of NaFY{sub 4}.

Homogenous BSCCO-2212 Round Wires for Very High Field Magnets

International Nuclear Information System (INIS)

Campbell, Scott; Holesinger, Terry; Huang, Ybing

2012-01-01

The performance demands on modern particle accelerators generate a relentless push towards higher field magnets. In turn, advanced high field magnet development places increased demands on superconducting materials. Nb3Sn conductors have been used to achieve 16 T in a prototype dipole magnet and are thought to have the capability for ∼18 T for accelerator magnets (primarily dipoles but also higher order multipole magnets). However there have been suggestions and proposals for such magnets higher than 20 T. The High Energy Physics Community (HEP) has identified important new physics opportunities that are enabled by extremely high field magnets: 20 to 50 T solenoids for muon cooling in a muon collider (impact: understanding of neutrinos and dark matter); and 20+ T dipoles and quadrupoles for high energy hadron colliders (impact: discovery reach far beyond present). This proposal addresses the latest SBIR solicitation that calls for grant applications that seek to develop new or improved superconducting wire technologies for magnets that operate at a minimum of 12 Tesla (T) field, with increases up to 15 to 20 T sought in the near future (three to five years). The long-term development of accelerator magnets with fields greater than 20 T will require superconducting wires having significantly better high-field properties than those possessed by current Nb 3 Sn or other A15 based wires. Given the existing materials science base for Bi-2212 wire processing, we believe that Bi 2 Sr 2 CaCu 2 O y (Bi-2212) round wires can be produced in km-long piece lengths with properties suitable to meet both the near term and long term needs of the HEP community. The key advance will be the translation of this materials science base into a robust, high-yield wire technology. While the processing and application of A15 materials have advanced to a much higher level than those of the copper oxide-based, high T c (HTS) counterparts, the HTS materials have the very significant advantage

New tests on the 40 kA Nb3Sn CEA conductor for ITER applications

International Nuclear Information System (INIS)

Duchateau, J.L.; Bessette, D.; Katheder, H.

1994-01-01

New tests have been performed on the 40 kA CEA Nb 3 Sn conductor in the Sultan III facility. The aim of these tests is to obtain key experimental data on the behaviour of Nb 3 Sn conductors for fusion applications under high field and large transport current. The 40 kA Nb 3 Sn CEA conductor has a shape and an internal arrangement of the superconducting wires which is very similar to the ITER conductors. The level of the ac losses experienced by these conductors under varying fields influences deeply their design. The basic experiment consists of producing field pulses on the conductor by means of a coil installed in the bore of the Sultan magnet and recording the integrated voltage obtained on pick-up coils placed on the conductor as a function of time. (author) 4 refs.; 5 figs.; 2 tabs

Production of Sn-117m in the BR2 high-flux reactor.

Science.gov (United States)

Ponsard, B; Srivastava, S C; Mausner, L F; Russ Knapp, F F; Garland, M A; Mirzadeh, S

2009-01-01

The BR2 reactor is a 100MW(th) high-flux 'materials testing reactor', which produces a wide range of radioisotopes for various applications in nuclear medicine and industry. Tin-117m ((117m)Sn), a promising radionuclide for therapeutic applications, and its production have been validated in the BR2 reactor. In contrast to therapeutic beta emitters, (117m)Sn decays via isomeric transition with the emission of monoenergetic conversion electrons which are effective for metastatic bone pain palliation and radiosynovectomy with lesser damage to the bone marrow and the healthy tissues. Furthermore, the emitted gamma photons are ideal for imaging and dosimetry.

Production of multifilamentary Nb3Sn composites incorporating a high tin bronze

International Nuclear Information System (INIS)

Petrovich, A.; Zeithlin, B.A.; Walker, M.S.

1977-01-01

The economics and processing methods have been examined for the fabrication of multifilamentary Nb 3 Sn using a high tin bronze reactive matrix. Four conductor configurations utilizing the high tin bronze were compared with a conventional Cu-13 wt % Sn bronze. The most promising of these designs is potentially 40% lower in cost per ampere meter than the conventional composite. Large hydrostatic extrusion facilities, which are required for the high tin processing, are not presently available in this country but can be made by conversion of conventional presses. They exist in Europe. Experiments were conducted to investigate the applicability of hydrostatic extrusion, and billet components were successfully prepared using the hydrostatic extrusion technique. We have concluded that the economics, availability of facilities and initial fabrication results are favorable for this type of conductor and that the next stage in this program of scale up to extrusion and drawing of 2'' to 3'' diameter composite billets should be undertaken

Quench Protection System Optimization for the High Luminosity LHC Nb $_3$Sn Quadrupoles

CERN Document Server

Ravaioli, E; Auchmann, B; Ferracin, P; Maciejewski, M; Rodriguez-Mateos, F; Sabbi, GL; Todesco, E; Verweij, A P

2017-01-01

The upgrade of the large hadron collider to achieve higher luminosity requires the installation of twenty-four 150 mm aperture, 12 T, $Nb_3Sn$ quadrupole magnets close to the two interaction regions at ATLAS and CMS. The protection of these high-field magnets after a quench is particularly challenging due to the high stored energy density, which calls for a fast, effective, and reliable protection system. Three design options for the quench protection system of the inner triplet circuit are analyzed, including quench heaters attached to the coil's outer and inner layer, Coupling-Loss Induced Quench (CLIQ), and combinations of those. The discharge of the magnet circuit and the electromagnetic and thermal transients occurring in the coils are simulated by means of the TALES and LEDET programs. The sensitivity to strand parameters and the effects of several failure cases on the coil's hot-spot temperature and peak voltages to ground are assessed. A protection system based only on quench heaters attached to the o...

Preliminary proposal of a Nb{sub 3}Sn quadrupole model for the low {beta} insertions of the LHC

Energy Technology Data Exchange (ETDEWEB)

Ambrosio, G; Ametrano, F; Bellomo, G; Broggi, F; Rossi, L; Volpini, G [Milan Univ. (Italy). Dip. di Fisica; [INFN, Sezione di Milano (Italy). Laboratorio Acceleratori e Superconduttivita` Applicata

1995-09-01

In recent years Nb{sub 3}Sn based conductors have shown wide applicability for superconducting magnets in many research areas like high field solenoids for laboratory experiment, for NMR spectroscopy and high field magnets for fusion. Nb{sub 3}Sn technology is progressing fast, increasing both technical reliability and availability. The Nb{sub 3}Sn technology, which has a higher critical field than NbTi, seems attractive for IR (Insertion Region) quadrupoles of large colliders . In this paper it is proposed the construction of a superconducting quadrupole wound with Nb{sub 3}Sn cable for a second generation IR inner triplet low {beta} quadrupoles, for the Large Hadron Collider at CERN. The low {beta} quadrupoles, control the beam focusing at collision points, therefore a gain in term of focus strength and/or coil aperture can increase significantly machine performance. Two are the main steps for the whole project: (1) design and construction of a 1 metre long quadrupole to demonstrate the actual feasibility, which is the subject of this proposal; (2) study for integration of the quadrupole in the machine and final design of 5 m long quadrupoles finalized to the LHC.

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

Science.gov (United States)

Aubin, J.; Hartmann, J. M.

2018-01-01

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

SnSe/carbon nanocomposite synthesized by high energy ball milling as an anode material for sodium-ion and lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, Zhian; Zhao, Xingxing; Li, Jie

2015-01-01

Graphical abstract: A homogeneous nanocomposite of SnSe and carbon black was synthesised by high energy ball milling and empolyed as an anode material for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). The nanocomposite anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Highlights: • A homogeneous nanocomposite of SnSe and carbon black was fabricated by high energy ball milling. • SnSe and carbon black are homogeneously mixed at the nanoscale level. • The SnSe/C anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Abstract: A homogeneous nanocomposite of SnSe and carbon black, denoted as SnSe/C nanocomposite, was fabricated by high energy ball milling and empolyed as a high performance anode material for both sodium-ion batteries and lithium-ion batteries. The X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy observations confirmed that SnSe in SnSe/C nanocomposite was homogeneously distributed within carbon black. The nanocomposite anode exhibited enhanced electrochemical performances including a high capacity, long cycling behavior and good rate performance in both sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). In SIBs, an initial capacitiy of 748.5 mAh g −1 was obtained and was maintained well on cycling (324.9 mAh g −1 at a high current density of 500 mA g −1 in the 200 th cycle) with 72.5% retention of second cycle capacity (447.7 mAh g −1 ). In LIBs, high initial capacities of approximately 1097.6 mAh g −1 was obtained, and this reduced to 633.1 mAh g −1 after 100 cycles at 500 mA g −1

Atomic disorder, phase transformation, and phase restoration in Co3Sn2

Science.gov (United States)

di, L. M.; Zhou, G. F.; Bakker, H.

1993-03-01

The behavior of the intermetallic compound Co3Sn2 upon ball milling was studied by x-ray diffraction, high-field-magnetization measurements, and subsequently by differential scanning calorimetry. It turns out that starting from the stoichiometric-ordered compound, mechanical attrition of Co3Sn2 generates atomic disorder in the early stage of milling. The nonequilibrium phase transformation from the low-temperature phase with orthorhombic structure to the high-temperature phase with a hexagonal structure was observed in the intermediate stage of milling. It was accompanied by the creation of increasing atomic disorder. After long milling periods, the phase transformation was completed and the atomic disordering became saturated. All the physical parameters measured in the present work remained constant during this period. The above outcome was confirmed by comparison with the high-temperature phase thermally induced by quenching. The good agreement of the results obtained by different techniques proves that the ball milling generates well-defined metastable states in Co3Sn2.

Ductile fracture mechanism of low-temperature In-48Sn alloy joint under high strain rate loading.

Science.gov (United States)

Kim, Jong-Woong; Jung, Seung-Boo

2012-04-01

The failure behaviors of In-48Sn solder ball joints under various strain rate loadings were investigated with both experimental and finite element modeling study. The bonding force of In-48Sn solder on an Ni plated Cu pad increased with increasing shear speed, mainly due to the high strain-rate sensitivity of the solder alloy. In contrast to the cases of Sn-based Pb-free solder joints, the transition of the fracture mode from a ductile mode to a brittle mode was not observed in this solder joint system due to the soft nature of the In-48Sn alloy. This result is discussed in terms of the relationship between the strain-rate of the solder alloy, the work-hardening effect and the resulting stress concentration at the interfacial regions.

Nb3Sn Quadrupoles Designs For The LHC Upgrades

International Nuclear Information System (INIS)

Felice, Helene

2008-01-01

In preparation for the LHC luminosity upgrades, high field and large aperture Nb 3 Sn quadrupoles are being studied. This development has to incorporate all the relevant features for an accelerator magnet like alignment and cooling channels. The LARP HQ model is a high field and large bore quadrupole that will meet these requirements. The 2-layer coils are surrounded by a structure based on key and bladder technology with supporting iron yoke and aluminum shell. This structure is aimed at pre-stress control, alignment and field quality. We present here the magnetic and mechanical design of HQ, along with recent progress on the development of the first 1-meter model.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Washabaugh, Pearce C.; Bregman, Joel N.

2013-01-01

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

Advances in Nb3Sn Performance

International Nuclear Information System (INIS)

Godeke, Arno

2008-01-01

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

Study of superconducting Nb{sub 3}Sn coils; Etude de bobinages supraconducteurs en Nb{sub 3}Sn

Energy Technology Data Exchange (ETDEWEB)

Vivet, B

1963-07-01

Composite superconducting Nb{sub 3}Sn wires with a diameter of 0.5 mm and a length of about 100 m were made, and Hc-Ic diagrams were plotted up to fields of 80 kgauss for short lengths. Two solenoids producing fields of about 20 kgauss were studied. Nb{sub 3}Sn solenoids, as opposed to those of Nb-Zr or Nb-Ti, appear to have a predictable behavior. Solenoids with less insulation produced stronger fields than heavily insulated solenoids. (author) [French] Une etude des fils composites supraconducteurs de Nb{sub 3}Sn a ete entreprise au C.E.N. Saclay, en collaboration avec la Societe S.O.D.E.R.X. Des fils de 0,5 mm de diametre et d'une centaine de metres de longueur ont ete produits de facon experimentale. Des diagrammes Hc-Ic ont pu etre traces, jusqu'en des champs de 80 kG, sur des echantillons de petite longueur. Deux solenoides ont ete etudies produisant les champs de l'ordre de 20 kg. Il semble que, contrairement aux alliages Nb-Zr ou Nb-Ti, les solenoides en Nb{sub 3}Sn aient un comportement previsible d'apres les tests sur des echantillons courts. On montrera d'autre part qu'un bobinage a faible isolement peut produire un champ notablement plus eleve qu'un bobinage isole. Une production plus extensive permettra, dans les semaines a venir, la fabrication de solenoides de plus grosse dimension et produisant des champs plus eleves. (auteur)

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)

Superconducting critical-current densities of commercial multifilamentary Nb3Sn(Ti) wires made by the bronze process

International Nuclear Information System (INIS)

Suenaga, M.; Tsuchiya, K.; Higuchi, N.; Tachikawa, K.

1985-01-01

Superconducting critical-current densities Jsub(c) in fields up to 24 T and at 4.2 and 1.8 K were measured for a number of commercial Nb 3 Sn wires which were alloyed with Ti. The best values of Jsub(c) at 20 T and at 4.2 and 1.8 K were 78 and 156 A mm -2 , respectively. In order to achieve these high current densities at H>20 T, it was shown that nonuniformity of the filaments had to be minimized. It was also shown that the grain size of Nb 3 Sn is not very important in determining Jsub(c) at these high magnetic fields, and that achieving high values of critical magnetic field Hsub(c2) is more important than small grain size. (author)

Enhanced thermoelectric property of oxygen deficient nickel doped SnO2 for high temperature application

Science.gov (United States)

Paulson, Anju; Sabeer, N. A. Muhammad; Pradyumnan, P. P.

2018-04-01

Motivated by the detailed investigation on the thermoelectric performance of oxide materials our work concentrated on the influence of acceptor dopants and defect density in the lattice plane for the enhancement of thermoelectric power. The series of Sn1‑x Nix O2 (0.01 ≤ x ≤ 0.05) compositions were prepared by solid state reaction mechanism and found that 3 atomic percentage Ni doped SnO2 can be considered as a good candidate due to its promising electrical and transport properties. Defect lattices were introduced in the sample and the deviation from oxygen stochiometry was ensured using photoluminescence measurement. High power factor was obtained for the 3 atomic percentage nickel doped SnO2 due to the effective number of charge carrier concentration and the depletion of oxygen rich layers. Defect centered and acceptor doped SnO2 lattice opens a new door for energy harvesting at higher temperatures.

Probing the ground state and zero-field cooled exchange bias by magnetoresistance measurement in Mn{sub 50}Ni{sub 41}Sn{sub 9} ribbon

Energy Technology Data Exchange (ETDEWEB)

Chen, Jiyun [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116 (China); Tu, Ruikang [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); School of Materials Science and Engineering, Soochow University, Suzhou 215000 (China); Fang, Xiaoting [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); Gu, Quanchao [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); School of Materials Science and Engineering, Soochow University, Suzhou 215000 (China); Zhou, Yanying [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); Cui, Rongjing [Department of Chemistry, Changshu Institute of Technology, Changshu 215500 (China); Han, Zhida, E-mail: han@cslg.edu.cn [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); Zhang, Lei; Fang, Yong [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); Qian, Bin, E-mail: njqb@cslg.edu.cn [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China); Zhang, Chengliang [School of Science, Jiangnan University, Wuxi 214122 (China); Jiang, Xuefan [Jiangsu Laboratory of Advanced Functional Materials, Department of Physics, Changshu Institute of Technology, Changshu 215500 (China)

2017-03-15

Recently, a new type of exchange bias (EB) after zero-field cooling has attracted considerable interest mainly in bulk magnetic competing systems. Here, we use a detailed magnetotransport investigation to probe the ground state and zero-field cooled EB (ZEB) in Mn{sub 50}Ni{sub 41}Sn{sub 9} ribbon. Both ZEB and field cooled EB were detected in magnetoresistance results consistent with magnetic measurement. A pure spin-glass ground state is proposed based on parabolic shape of low-field magnetoresistance combined with AC magnetization, memory effect. The appearance of ZEB is attributed to the field-induced nucleation and growth of ferromagnetic domains in the spin glass matrix forming unidirectional anisotropy at the interface. - Highlights: • Magnetoresistance was first used to probe the ground state and ZEB in Ni-Mn-based alloys. • A pure spin-glass ground state is proposed in Mn{sub 50}Ni{sub 41}Sn{sub 9} ribbon. • Field-induced nucleation and growth of ferromagnetic domains in SG results in ZEB.

There-dimensional porous carbon network encapsulated SnO2 quantum dots as anode materials for high-rate lithium ion batteries

International Nuclear Information System (INIS)

Yang, Juan; Xi, Lihua; Tang, Jingjing; Chen, Feng; Wu, Lili; Zhou, Xiangyang

2016-01-01

SnO 2 quantum dots have attracted enormous interest, since they have been shown to effectively minimize the volume change stress, improve the anode kinetic and shorten the lithium ion migration distance when used as anode materials for lithium ion battery. In this work, we report a facile strategy to fabricate nanostructure with homogenous SnO 2 quantum dots anchored on three-dimensional (3D) nitrogen and sulfur dual-doped porous carbon (NSGC@SnO 2 ). Characterization results show that the obtained SnO 2 quantum dots have an average critical size of 3–5 nm and uniformly encapsulated in the porous of NSGC matrix. The as-designed nanostructure can effectively avoid the aggregation of SnO 2 quantum dots as well as accommodate the mechanical stress induced by the volume change of SnO 2 quantum dots and thus maintain the structure integrity of the electrode. As a result, the obtained NSGC@SnO 2 composite exhibits a specific reversible capacity as high as 1118 mAh g −1 at a current of 200 mA g −1 after 100 cycles along with a high coulombic efficiency of 98% and excellent rate capability.

A novel route to graphite-like carbon supporting SnO{sub 2} with high electron transfer and photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Chen, Xianjie; Liu, Fenglin; Liu, Bing [Hubei Collaborative Innovation Center for Advanced Organochemical Materials, Hubei University, Wuhan 430062 (China); Ministry of Education Key Laboratory for the Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Tian, Lihong, E-mail: tian7978@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organochemical Materials, Hubei University, Wuhan 430062 (China); Ministry of Education Key Laboratory for the Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Hu, Wei; Xia, Qinghua [Hubei Collaborative Innovation Center for Advanced Organochemical Materials, Hubei University, Wuhan 430062 (China); Ministry of Education Key Laboratory for the Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China)

2015-04-28

Highlights: • Mesoporous nanocomposites that graphite-like carbon supporting SnO{sub 2} are prepared by solvothermal method combined with a post- calcination. • The polyvinylpyrrolidone not only promotes the nucleation and crystallization but also provides the carbon source in the process. • The graphite-like carbon hinders the recombination of photogenerated electron and holes efficiently. • The mesoporous carbon–SnO{sub 2} nanocomposite shows high photocatalytic activity on the degradation of Rhodamine B and glyphosate under simulated sunlight. - Abstract: Mesoporous graphite-like carbon supporting SnO{sub 2} (carbon–SnO{sub 2}) nanocomposites were prepared by a modified solvothermal method combined with a post-calcination at 500 °C under a nitrogen atmosphere. The polyvinylpyrrolidone not only promotes the nucleation and crystallization, but also provides the carbon source in the process. The results of scanning electron microscopy and transmission electron microscopy show a uniform distribution of SnO{sub 2} nanoparticles on the graphite- like carbon surface. Raman and X-ray photoelectron spectra indicate the presence of strong C–Sn interaction between SnO{sub 2} and graphite-like carbon. Photoelectrochemical measurements confirm that the effective separation of electron–hole pairs on the carbon–SnO{sub 2} nanocomposite leads to a high photocatalytic activity on the degradation of Rhodamine B and glyphosate under simulated sunlight irradiation. The nanocomposite materials show a potential application in dealing with the environmental and industrial contaminants under sunlight irradiation.

Studies on advanced superconductors for fusion device. Pt. 2. Metallic superconductors other than Nb{sub 3}Sn

Energy Technology Data Exchange (ETDEWEB)

Tachikawa, K.; Yamamoto, J.; Mito, T. [eds.

1997-03-01

A comprehensive report on the present status of the development of Nb{sub 3}Sn superconductors was published as the NIFS-MEMO-20 in March, 1996 (Part 1 of this report series). The second report of this study covers various progress so far achieved in the research and development on advanced metallic superconductors other than Nb{sub 3}Sn. Among different A15 crystal-type compounds, Nb{sub 3}Al has been fabricated into cables with large current-carrying capacity for fusion device referring its smaller sensitivity to mechanical strain than Nb{sub 3}Sn. Other high-field A15 superconductors, e.g. V{sub 3}Ga, Nb{sub 3}Ge and Nb{sub 3}(Al,Ge), have been also fabricated through different novel processes as promising alternatives to Nb{sub 3}Sn conductors. Meanwhile, B1 crystal-type NbN and C15 crystal-type V{sub 2}(Hf,Zr) high-field superconductors are characterized by their excellent tolerance to mechanical strain and neutron irradiation. Chevrel-type PbMo{sub 6}S{sub 8} compound has gained much interests due to its extremely high upper critical field. In addition, this report includes the recent progress in ultra-fine filamentary NbTi wires for AC use, and that in NbTi/Cu magnetic shields necessary in the application of high magnetic field. The data on the decay of radioactivity in a variety of metals relating to fusion superconducting magnet are also attached as appendices. We hope that this report might contribute substantially as a useful reference for the planning of fusion apparatus of next generation as well as that of other future superconducting devices. (author)

Noncollinear antiferromagnetic Mn3Sn films

Science.gov (United States)

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

2018-05-01

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

Thermal fluctuations in the classical superconductor Nb3Sn from high-resolution specific-heat measurements

International Nuclear Information System (INIS)

Lortz, Rolf; Wang Yuxing; Junod, Alain; Toyota, Naoki

2007-01-01

The range of thermal fluctuations in 'classical' bulk superconductors is extremely small and especially in low-fields hardly experimentally accessible. With a new type of calorimeter we were able to detect a tiny lambda anomaly in the specific-heat of the superconductor Nb 3 Sn within a narrow temperature range around the H c2 line. We show that the evolution of the anomaly as a function of magnetic field follows scaling laws expected in the presence of critical thermal fluctuations

Nb$_{3}$Sn quadrupole magnets for the LHC IR

CERN Document Server

Sabbi, G L; Chiesa, L; Coccoli, M; Dietderich, D R; Ferracin, P; Gourlay, S A; Hafalia, R R; Lietzke, A F; McInturff, A D; Scanlan, R M

2003-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 * 10/sup 34/ cm/sup -2/s/sup -1/ at the Large Hadron Collider (LHC). At present, Nb/sub 3/Sn is the only practical conductor which can meet these requirements. Since Nb/sub 3/Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented. (25 refs).

Nb3Sn Quadrupole Magnets for the LHC IR

International Nuclear Information System (INIS)

Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

2001-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10 34 cm -2 s -1 at the Large Hadron Collider (LHC). At present, Nb 3 Sn is the only practical conductor which can meet these requirements. Since Nb 3 Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

Exploration work function and optical properties of monolayer SnSe allotropes

Science.gov (United States)

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

2018-02-01

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

High-Resolution Tracking Asymmetric Lithium Insertion and Extraction and Local Structure Ordering in SnS2.

Science.gov (United States)

Gao, Peng; Wang, Liping; Zhang, Yu-Yang; Huang, Yuan; Liao, Lei; Sutter, Peter; Liu, Kaihui; Yu, Dapeng; Wang, En-Ge

2016-09-14

In the rechargeable lithium ion batteries, the rate capability and energy efficiency are largely governed by the lithium ion transport dynamics and phase transition pathways in electrodes. Real-time and atomic-scale tracking of fully reversible lithium insertion and extraction processes in electrodes, which would ultimately lead to mechanistic understanding of how the electrodes function and why they fail, is highly desirable but very challenging. Here, we track lithium insertion and extraction in the van der Waals interactions dominated SnS2 by in situ high-resolution TEM method. We find that the lithium insertion occurs via a fast two-phase reaction to form expanded and defective LiSnS2, while the lithium extraction initially involves heterogeneous nucleation of intermediate superstructure Li0.5SnS2 domains with a 1-4 nm size. Density functional theory calculations indicate that the Li0.5SnS2 is kinetically favored and structurally stable. The asymmetric reaction pathways may supply enlightening insights into the mechanistic understanding of the underlying electrochemistry in the layered electrode materials and also suggest possible alternatives to the accepted explanation of the origins of voltage hysteresis in the intercalation electrode materials.

Electrospinning direct preparation of SnO2/Fe2O3 heterojunction nanotubes as an efficient visible-light photocatalyst

International Nuclear Information System (INIS)

Zhu, Chengquan; Li, Yuren; Su, Qing; Lu, Bingan; Pan, Jiaqi; Zhang, Jiawang; Xie, Erqing; Lan, Wei

2013-01-01

Highlights: •SnO 2 /Fe 2 O 3 nano-heterojunction-tubes are prepared by a facile electrospinning technique. •The formation mechanism of heterojunction tubes is proposed for self-polymer-templates action. •SnO 2 /Fe 2 O 3 nano-heterojunction-tubes show high photocatalytic activity under visible light irradiation. •The reasons for the high photocatalytic activity are investigated in detail. -- Abstract: Herein SnO 2 /Fe 2 O 3 heterojunction nanotubes are prepared by a facile electrospinning technique. The heterojunction nanotubes with a diameter of about 200 nm uniformly distribute SnO 2 and Fe 2 O 3 nanocrystals and present the obvious interfaces between them, which form perfect SnO 2 /Fe 2 O 3 nano-heterojunctions. A possible mechanism based on self-polymer-templates is proposed to explain the formation of SnO 2 /Fe 2 O 3 heterojunction nanotubes. The heterojunction nanotubes show high photocatalytic activity for the degradation of RhB dye under visible light irradiation. The prepared SnO 2 /Fe 2 O 3 heterojunction nanotubes can also be applied to other fields such as sensor, lithium-ion batteries

Magnetic and Structural Design of a 15 T $Nb_3Sn$ Accelerator Depole Model

Energy Technology Data Exchange (ETDEWEB)

Kashikhin, V. V. [Fermilab; Andreev, N. [Fermilab; Barzi, E. [Fermilab; Novitski, I. [Fermilab; Zlobin, A. V. [Fermilab

2015-01-01

Hadron Colliders (HC) are the most powerful discovery tools in modern high energy physics. A 100 TeV scale HC with a nominal operation field of at least 15 T is being considered for the post-LHC era. The choice of a 15 T nominal field requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T $Nb_{3}Sn$ dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance. The experience gained during the 11-T dipole R&D campaign is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T $Nb_3Sn$ dipole and the steps towards the demonstration model.

Evidence for highly localized damage in internal tin and powder-in-tube Nb{sub 3}Sn strands rolled before reaction obtained from coupled magneto-optical imaging and confocal laser scanning microscopy

Energy Technology Data Exchange (ETDEWEB)

Polyanskii, A A; Lee, P J; Jewell, M C; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Barzi, E; Turrioni, D; Zlobin, A V [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2009-09-15

Nb{sub 3}Sn strands for high-current, high-field magnets must be cabled before reaction while the conductor is still composed of ductile components. Even though still in the ductile, deformable state, significant damage can occur in this step, which expresses itself by inhomogeneous A15 formation, Sn leakage or even worse effects during later reaction. In this study, we simulate cabling damage by rolling recent high performance powder-in-tube (PIT) and internal tin (IT) strands in controlled increments, applying standard Nb{sub 3}Sn reaction heat treatments, and then examining the local changes using magneto-optical imaging (MOI), scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). These combined characterizations allow any local damage to the filament architecture to be made clear. MOI directly reveals the local variation of superconductivity while CLSM is extremely sensitive in revealing Sn leakage beyond the diffusion barrier into the stabilizing Cu. These techniques reveal a markedly different response to deformation by the PIT and IT strands. The study demonstrates that these tools can provide a local, thorough, and detailed view of how strands degrade and thus complement more complex extracted strand studies.

Using permanent magnets to boost the dipole field for the High-Energy LHC

CERN Document Server

Zimmermann, Frank

2012-01-01

The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb- Ti, Nb$_{3}$Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability in principle.

Facile solvothermal synthesis of highly active and robust Pd1.87Cu0.11Sn electrocatalyst towards direct ethanol fuel cell applications

Science.gov (United States)

Jana, Rajkumar; Dhiman, Shikha; Peter, Sebastian C.

2016-08-01

Ordered intermetallic Pd1.87Cu0.11Sn ternary electrocatalyst has been synthesized by sodium borohydride reduction of precursor salts Pd(acac)2, CuCl2.2H2O and SnCl2 using one-pot solvothermal synthesis method at 220 °C with a reaction time of 24 h. To the best of our knowledge, here for the first time we report surfactant free synthesis of a novel ordered intermetallic ternary Pd1.87Cu0.11Sn nanoparticles. The ordered structure of the catalyst has been confirmed by powder x-ray diffraction, transmission electron microscopy (TEM). Composition and morphology of the nanoparticles have been confirmed through field emission scanning electron microscopy, energy-dispersive spectrometry and TEM. The electrocatalytic activity and stability of the ternary electrocatalyst towards ethanol oxidation in alkaline medium was investigated by cyclic voltammetry and chronoamperometry techniques. The catalyst is proved to be highly efficient and stable upto 500th cycle and even better than commercially available Pd/C (20 wt%) electrocatalysts. The specific and mass activity of the as synthesized ternary catalyst are found to be ∼4.76 and ∼2.9 times better than that of commercial Pd/C. The enhanced activity and stability of the ordered ternary Pd1.87Cu0.11Sn catalyst can make it as a promising candidate for the alkaline direct ethanol fuel cell application.

Hydrothermal synthesis and electrochemical properties of nano-sized Co-Sn alloy anodes for lithium ion batteries

International Nuclear Information System (INIS)

He Jianchao; Zhao Hailei; Wang Jing; Wang Jie; Chen Jingbo

2010-01-01

Research highlights: → Nano-sized Co-Sn alloys were synthesized by hydrothermal route. → Li 2 O and CoSn can buffer the large volume change associated with lithiation of Sn. → A two-step reaction mechanism of CoSn 2 alloy during cycling was confirmed. - Abstract: Nano-sized Co-Sn alloys with a certain amount of Sn oxides used as potential anode materials for lithium ion batteries were synthesized by hydrothermal route. The effects of hydrothermal conditions and post annealing on the phase compositions and the electrochemical properties of synthesized powders were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) with energy dispersive spectra (EDS) analysis and galvanostatic cycling tests. Prolonging the dwelling time at the same hydrothermal temperature can increase the content of Sn oxides, which will lead to a high initial irreversible capacity loss but a better cycling stability owing to the buffer effect of irreversible product Li 2 O. Heat-treatment can increase the crystallinity and cause the presence of a certain amount of inert CoSn component, which both have positive impact on the cycling stability of Co-Sn electrode. By comparison with the lithiation/delithiation processes of metal Sn, a two-step mechanism of CoSn 2 alloy during cycling was confirmed.

Critical current, electro-mechanical properties and specific heat of bronze Nb{sub 3}Sn conductors

Energy Technology Data Exchange (ETDEWEB)

Uglietti, D.; Seeber, B.; Abacherli, V.; Flukiger, R. [Geneva Univ., Groupe Applique de Physique (GAP) (Switzerland); Wang, X.Y.; Junod, A.; Flukiger, R. [Geneva Univ., Dept. Phys. Mat. Condensee (DPMC) (Switzerland)

2004-07-01

The fabrication process leading to a Nb{sub 3}Sn wire by using the bronze route with 15.4 wt per cent of Sn is described. The critical current density, J{sub c}, is studied as a function of the applied magnetic field, B, up to 25 T; the uniaxial strain, {epsilon}, was measured up to 17. In the second part our device for measuring I{sub c}({epsilon}) is presented. The device is based on the concept of the Walters spring (WASP), which allows to measure long length wires (voltage taps distance up to 50 cm), up to 1000 A and to obtain an absolute measurement of the strain value. It is thus possible to measure the voltage-current relation of technical superconducting wires and tapes down to 0.01 {mu}V/cm, an important requirement for the characterisation in view of applications like NMR high field magnets which require persistent mode operation with high current densities. Finally specific heat measurements on Nb{sub 3}Sn wires prepared at GAP have allowed to determine for the first time the overall distribution of T{sub c} in the filaments. The onset of T{sub c} was observed at 17.2 K, the T{sub c} distribution being centred at 15.9 K. This analysis confirms the reduction of T{sub c} due to the Ti addition and the presence of a distribution of Sn in Nb{sub 3}Sn bronze wires. (authors)

Tunneling Diode Based on WSe2 /SnS2 Heterostructure Incorporating High Detectivity and Responsivity.

Science.gov (United States)

Zhou, Xing; Hu, Xiaozong; Zhou, Shasha; Song, Hongyue; Zhang, Qi; Pi, Lejing; Li, Liang; Li, Huiqiao; Lü, Jingtao; Zhai, Tianyou

2018-02-01

van der Waals (vdW) heterostructures based on atomically thin 2D materials have led to a new era in next-generation optoelectronics due to their tailored energy band alignments and ultrathin morphological features, especially in photodetectors. However, these photodetectors often show an inevitable compromise between photodetectivity and photoresponsivity with one high and the other low. Herein, a highly sensitive WSe 2 /SnS 2 photodiode is constructed on BN thin film by exfoliating each material and manually stacking them. The WSe 2 /SnS 2 vdW heterostructure shows ultralow dark currents resulting from the depletion region at the junction and high direct tunneling current when illuminated, which is confirmed by the energy band structures and electrical characteristics fitted with direct tunneling. Thus, the distinctive WSe 2 /SnS 2 vdW heterostructure exhibits both ultrahigh photodetectivity of 1.29 × 10 13 Jones (I ph /I dark ratio of ≈10 6 ) and photoresponsivity of 244 A W -1 at a reverse bias under the illumination of 550 nm light (3.77 mW cm -2 ). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluorine-doped SnO2 nanoparticles anchored on reduced graphene oxide as a high-performance lithium ion battery anode

Science.gov (United States)

Cui, Dongming; Zheng, Zhong; Peng, Xue; Li, Teng; Sun, Tingting; Yuan, Liangjie

2017-09-01

The composite of fluorine-doped SnO2 anchored on reduced graphene oxide (F-SnO2/rGO) has been synthesized through a hydrothermal method. F-SnO2 particles with average size of 8 nm were uniformly anchored on the surfaces of rGO sheets and the resulting composite had a high loading of F-SnO2 (ca. 90%). Benefiting from the remarkably improved electrical conductivity and Li-ion diffusion in the electrode by F doping and rGO incorporation, the composite material exhibited high reversible capacity, excellent long-term cycling stability and superior rate capability. The electrode delivered a large reversible capacity of 1037 mAh g-1 after 150 cycles at 100 mA g-1 and high rate capacities of 860 and 770 mAh g-1 at 1 and 2 A g-1, respectively. Moreover, the electrode could maintain a high reversible capacities of 733 mAh g-1 even after 250 cycles at 500 mA g-1. The outstanding electrochemical performance of the as-synthesized composite make it a promising anode material for high-energy lithium ion batteries.

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

Two-dimensional n -InSe/p -GeSe(SnS) van der Waals heterojunctions: High carrier mobility and broadband performance

Science.gov (United States)

Xia, Cong-xin; Du, Juan; Huang, Xiao-wei; Xiao, Wen-bo; Xiong, Wen-qi; Wang, Tian-xing; Wei, Zhong-ming; Jia, Yu; Shi, Jun-jie; Li, Jing-bo

2018-03-01

Recently, constructing van der Waals (vdW) heterojunctions by stacking different two-dimensional (2D) materials has been considered to be effective strategy to obtain the desired properties. Here, through first-principles calculations, we find theoretically that the 2D n -InSe/p -GeSe(SnS) vdW heterojunctions are the direct-band-gap semiconductor with typical type-II band alignment, facilitating the effective separation of photogenerated electron and hole pairs. Moreover, they possess the high optical absorption strength (˜105 ), broad spectrum width, and excellent carrier mobility (˜103c m2V-1s-1 ). Interestingly, under the influences of the interlayer coupling and external electric field, the characteristics of type-II band alignment is robust, while the band-gap values and band offset are tunable. These results indicate that 2D n -InSe/p -GeSe(SnS) heterojunctions possess excellent optoelectronic and transport properties, and thus can become good candidates for next-generation optoelectronic nanodevices.

The influence of high gravity in PbSn eutectic alloy

Energy Technology Data Exchange (ETDEWEB)

Freitas, F.E.; Toledo, R.C.; Poli, A.K.S.; An, C.Y.; Bandeira, I.N., E-mail: filipe.estevao@gmail.com, E-mail: chen@las.inpe.br [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

2014-07-01

The study of materials processed in centrifuges improves the understanding of the acceleration influence in the convection behavior in materials processing. This work aims to study the influence of high gravity in PbSn eutectic alloy solidification using a small centrifuge designed and built in the Associate Laboratory of Sensors and Materials of the Brazilian Space Research Institute (LAS/INPE). The samples were analyzed by densitometry and scanning electron microscopy (SEM). (author)

Development and test of Nb(3)Sn cos-theta dipoles based on PIT strands

International Nuclear Information System (INIS)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chichili, D.R.; Elementi, L.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Yamada, R.

2004-01-01

Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb 3 Sn strands produced using different technologies. Two 1-m long models--mirror configuration and dipole magnet--were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb 3 Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing

Sandwich-like C@SnO2/Sn/void@C hollow spheres as improved anode materials for lithium ion batteries

Science.gov (United States)

Wang, Huijun; Jiang, Xinya; Chai, Yaqin; Yang, Xia; Yuan, Ruo

2018-03-01

As lithium ion batteries (LIBs) anode, SnO2 suffers fast capacity fading due to its large volume expansion during discharge/charge process. To overcome the problem, sandwich-like C@SnO2/Sn/void@C hollow spheres (referred as C@SnO2/Sn/void@C HSs) are prepared by in-situ polymerization and carbonization, using hollow SnO2 as self-template and dopamine as carbon source. The C@SnO2/Sn/void@C HSs possesses the merits of hollow and core/void/shell structure, so that they can accommodate the volume change under discharge/charge process, shorten the transmission distance of Li ions, own more contact area for the electrolyte. Thanks to these advantages, C@SnO2/Sn/void@C HSs display excellent electrochemical performance as anode materials for LIBs, which deliver a high capacity of 786.7 mAh g-1 at the current density of 0.5 A g-1 after 60 cycles. The simple synthesis method for C@SnO2/Sn/void@C HSs with special structure will provide a promising method for preparing other anode materials for LIBs.

High-energy γ-ray observations of SN 1987A

International Nuclear Information System (INIS)

Sood, R.K.; Thomas, J.A.; Waldron, L.; Manchanda, R.K.; Rochester, G.K.; Sumner, T.J.; Frye, G.; Jenkins, T.; Koga, R.; Ubertini, P.; Bazzano, A.; La Padula, C.; Staubert, R.; Kendziorra, E.

1988-01-01

SN 1987A has been observed with a combined high energy γ-ray (50-500 MeV) and hard X-ray (15-50 keV) payload during a balloon flight on 5 April 1988 from Alice Springs, Australia. The γ-ray observations, along with our earlier ones on 19 April 1987 are the only such observations of the supernova to date. The γ-ray detector characteristics are described. The preliminary results of the recent flight and their implications in terms of the known supernova parameters are discussed. 17 refs., 6 figs

Superconductivity of a Sn film controlled by an array of Co nanowires

Science.gov (United States)

Wei, Z.; Ye, Z.; Rathnayaka, K. D. D.; Lyuksyutov, I. F.; Wu, W.; Naugle, D. G.

2012-09-01

Superconducting properties of a hybrid structure composed of ferromagnetic Co nanowire arrays and a superconducting Sn film have been investigated. Ordered Co nanowires arrays with 60 nm, 150 nm and 200 nm diameter were electroplated into the pores of self organized Anodic Aluminum Oxide (AAO) membranes. Hysteretic dependence of the Sn film superconducting properties on applied magnetic field and critical current enhancement at moderate fields has been observed. This behavior strongly depends on the ratio of the Sn film thickness to the Co nanowire diameter.

Superconductivity of a Sn film controlled by an array of Co nanowires

International Nuclear Information System (INIS)

Wei, Z.; Ye, Z.; Rathnayaka, K.D.D.; Lyuksyutov, I.F.; Wu, W.; Naugle, D.G.

2012-01-01

Superconducting properties of a hybrid structure composed of ferromagnetic Co nanowire arrays and a superconducting Sn film have been investigated. Ordered Co nanowires arrays with 60 nm, 150 nm and 200 nm diameter were electroplated into the pores of self organized Anodic Aluminum Oxide (AAO) membranes. Hysteretic dependence of the Sn film superconducting properties on applied magnetic field and critical current enhancement at moderate fields has been observed. This behavior strongly depends on the ratio of the Sn film thickness to the Co nanowire diameter.

Cu-SnO2 nanostructures obtained via galvanic replacement control as high performance anodes for lithium-ion storage

Science.gov (United States)

Nguyen, Tuan Loi; Park, Duckshin; Hur, Jaehyun; Son, Hyung Bin; Park, Min Sang; Lee, Seung Geol; Kim, Ji Hyeon; Kim, Il Tae

2018-01-01

SnO2 has been considered as a promising anode material for lithium ion batteries (LIBs) because of its high theoretical capacity (782 mAh g-1). However, the reaction between lithium ions and Sn causes a large volume change, resulting in the pulverization of the anode, a loss of contact with the current collector, and a deterioration in electrochemical performance. Several strategies have been proposed to mitigate the drastic volume changes to extend the cyclic life of SnO2 materials. Herein, novel composites consisting of Cu and SnO2 were developed via the galvanic replacement reaction. The reaction was carried out at 180 °C for different durations and triethylene glycol was used as the medium solvent. The structure, morphology, and composition of the composites were analyzed by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The reaction time affected the particle size, which in turn affected the reaction kinetics. Furthermore, the novel nanostructures contained an inactive metal phase (Cu), which acted both as the buffer space against the volume change of Sn during the alloying reaction and as the electron conductor, resulting in a lower impedance of the composites. When evaluated as potential anodes for LIBs, the composite electrodes displayed extraordinary electrochemical performance with a high capacity and Coulombic efficiency, an excellent cycling stability, and a superior rate capability compared to a Sn electrode.

Enhanced hydrogen storage capacity of Ni/Sn-coated MWCNT nanocomposites

Science.gov (United States)

Varshoy, Shokufeh; Khoshnevisan, Bahram; Behpour, Mohsen

2018-02-01

The hydrogen storage capacity of Ni-Sn, Ni-Sn/multi-walled carbon nanotube (MWCNT) and Ni/Sn-coated MWCNT electrodes was investigated by using a chronopotentiometry method. The Sn layer was electrochemically deposited inside pores of nanoscale Ni foam. The MWCNTs were put on the Ni-Sn foam with nanoscale porosities using an electrophoretic deposition method and coated with Sn nanoparticles by an electroplating process. X-ray diffraction and energy dispersive spectroscopy results indicated that the Sn layer and MWCNTs are successfully deposited on the surface of Ni substrate. On the other hand, a field-emission scanning electron microscopy technique revealed the morphology of resulting Ni foam, Ni-Sn and Ni-Sn/MWCNT electrodes. In order to measure the hydrogen adsorption performed in a three electrode cell, the Ni-Sn, Ni-Sn/MWCNT and Ni/Sn-coated MWCNT electrodes were used as working electrodes whereas Pt and Ag/AgCl electrodes were employed as counter and reference electrodes, respectively. Our results on the discharge capacity in different electrodes represent that the Ni/Sn-coated MWCNT has a maximum discharge capacity of ˜30 000 mAh g-1 for 20 cycles compared to that of Ni-Sn/MWCNT electrodes for 15 cycles (˜9500 mAh g-1). By increasing the number of cycles in a constant current, the corresponding capacity increases, thereby reaching a constant amount for 20 cycles.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-08-01

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

Continuous, flexible, and high-strength superconducting Nb3Ge and Nb3Sn filaments

International Nuclear Information System (INIS)

Ahmad, I.; Heffernan, W.J.

1976-01-01

Fabrication of continuous, flexible, and high-strength (1600 MN/m 2 ) composite filaments of Nb 3 Ge (T/subc/ 18 0 K) and Nb 3 Sn is reported, involving chemical vapor deposition of these compounds on Nb-coated high-strength W--1% ThO 2 filaments

TDPAC study of Cd-doped SnO

Energy Technology Data Exchange (ETDEWEB)

Munoz, E. L., E-mail: munoz@fisica.unlp.edu.ar [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina); Carbonari, A. W. [Instituto de Pesquisas Energeticas y Nucleares-IPEN-CNEN/SP (Brazil); Errico, L. A. [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina); Bibiloni, A. G. [Universidad Nacional de La Plata, Departamento de Fisica, Facultad de Ciencias Exactas (Argentina); Petrilli, H. M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil); Renteria, M. [Universidad Nacional de La Plata, Departamento de Fisica-IFLP (CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas (Argentina)

2007-07-15

The combination of hyperfine techniques and ab initio calculations has been shown to be a powerful tool to unravel structural and electronic characterizations of impurities in solids. A recent example has been the study of Cd-doped SnO, where ab initio calculations questioned previous TDPAC assignments of the electric-field gradient (EFG) in {sup 111}In-implanted Sn-O thin films. Here we present new TDPAC experiments at {sup 111}In-diffused polycrystalline SnO. A reversible temperature dependence of the EFG was observed in the range 295-900 K. The TDPAC results were compared with theoretical calculations performed with the full-potential linearized augmented plane wave (FP-LAPW) method, in the framework of the density functional theory. Through the comparison with the theoretical results, we infer that different electronic surroundings around Cd impurities can coexist in the SnO sample.

TDPAC study of Cd-doped SnO

International Nuclear Information System (INIS)

Munoz, E. L.; Carbonari, A. W.; Errico, L. A.; Bibiloni, A. G.; Petrilli, H. M.; Renteria, M.

2007-01-01

The combination of hyperfine techniques and ab initio calculations has been shown to be a powerful tool to unravel structural and electronic characterizations of impurities in solids. A recent example has been the study of Cd-doped SnO, where ab initio calculations questioned previous TDPAC assignments of the electric-field gradient (EFG) in 111 In-implanted Sn-O thin films. Here we present new TDPAC experiments at 111 In-diffused polycrystalline SnO. A reversible temperature dependence of the EFG was observed in the range 295-900 K. The TDPAC results were compared with theoretical calculations performed with the full-potential linearized augmented plane wave (FP-LAPW) method, in the framework of the density functional theory. Through the comparison with the theoretical results, we infer that different electronic surroundings around Cd impurities can coexist in the SnO sample.

Mössbauer and heat capacity studies of ErZnSn2

Directory of Open Access Journals (Sweden)

Łątka Kazimierz

2017-06-01

Full Text Available Heat capacity results obtained for the intermetallic compound ErZnSn2 were re-analysed to also consider, apart from the classical Debye model, the anharmonicity of the crystal lattice and the proper set of Einstein modes. The 119mSn Mössbauer technique was applied to derive the hyperfine interaction parameters characteristic of the two inequivalent crystallographic Sn sites in the compound studied. Quadrupole interaction constants, as measured by 119mSn Mössbauer spectroscopy, allowed for estimations of Vzz components of the electric field gradient tensor that exist at both Sn sites in the discussed compound.

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.

HIGH RESOLUTION 36 GHz IMAGING OF THE SUPERNOVA REMNANT OF SN 1987A

International Nuclear Information System (INIS)

Potter, T. M.; Staveley-Smith, L.; Zanardo, G.; Ng, C.-Y.; Gaensler, B. M.; Ball, Lewis; Kesteven, M. J.; Manchester, R. N.; Tzioumis, A. K.

2009-01-01

The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend the frequency range of an ongoing monitoring and imaging program conducted between 1.4 and 20 GHz. Our 36.2 GHz images have a diffraction-limited angular resolution of 0.''3-0.''4, which covers the gap between high resolution, low dynamic range VLBI images of the remnant and low resolution, high dynamic range images at frequencies between 1 and 20 GHz. The radio morphology of the remnant at 36 GHz is an elliptical ring with enhanced emission on the eastern and western sides, similar to that seen previously at lower frequencies. Model fits to the data in the Fourier domain show that the emitting region is consistent with a thick inclined torus of mean radius 0.''85, and a 2008 October flux density of 27 ± 6 mJy at 36.2 GHz. The spectral index for the remnant at this epoch, determined between 1.4 GHz and 36.2 GHz, is α = -0.83. There is tentative evidence for an unresolved central source with flatter spectral index.

Highly Sensitive Nanostructured SnO2 Thin Films For Hydrogen Sensing

Science.gov (United States)

Patil, L. A.; Shinde, M. D.; Bari, A. R.; Deo, V. V.

2010-10-01

Nanostructured SnO2 thin films were prepared by ultrasonic spray pyrolysis technique. Aqueous solution (0.05 M) of SnCl4ṡ5H2O in double distilled water was chosen as the starting solution for the preparation of the films. The stock solution was delivered to nozzle with constant and uniform flow rate of 70 ml/h by Syringe pump SK5001. Sono-tek spray nozzle, driven by ultrasonic frequency of 120 kHz, converts the solution into fine spray. The aerosol produced by nozzle was sprayed on glass substrate heated at 150 °C. The sensing performance of the films was tested for various gases such as LPG, hydrogen, ethanol, carbon dioxide and ammonia. The sensor (30 min) showed high gas response (S = 3040 at 350 °C) on exposure of 1000 ppm of hydrogen and high selectivity against other gases. Its response time was short (2 s) and recovery was also fast (12 s). To understand reasons behind this uncommon gas sensing performance of the films, their structural, microstructural, and optical properties were studied using X-ray diffraction, electron microscopy (SEM and TEM) respectively. The results are interpreted

Dual Carbon-Confined SnO2 Hollow Nanospheres Enabling High Performance for the Reversible Storage of Alkali Metal Ions.

Science.gov (United States)

Wu, Qiong; Shao, Qi; Li, Qiang; Duan, Qian; Li, Yanhui; Wang, Heng-Guo

2018-04-25

To explore a universal electrode material for the high-performance electrochemical storage of Li + , Na + , and K + ions remains a big challenge. Herein, we propose a "trinity" strategy to coat the SnO 2 hollow nanospheres using the dual carbon layer from the polydopamine-derived nitrogen-doped carbon and graphene. Thereinto, hollow structures with sufficient void space could buffer the volume expansion, whereas dual carbon-confined strategy could not only elastically prevent the aggregation of nanoparticle and ensure the structural integrity but also immensely improve the conductivity and endow high rate properties. Benefiting from the effective strategy and specific structure, the dual carbon-confined SnO 2 hollow nanosphere (denoted as G@C@SnO 2 ) can serve as the universal host material for alkali metal ions and enable their rapid and reversible storage. As expected, the resulting G@C@SnO 2 as a universal anode material shows reversible alkali-metal-ion storage with high performance. We believe this that strategy could pave the way for constructing other metal-oxide-based dual carbon-confined high-performance materials for the future energy storage applications.

A comparative study of ternary Al-Sn-Cu immiscible alloys prepared by conventional casting and casting under high-intensity ultrasonic irradiation

Energy Technology Data Exchange (ETDEWEB)

Kotadia, H.R., E-mail: hiren.kotadia@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Das, A. [Materials Research Centre, College of Engineering, Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom); Doernberg, E.; Schmid-Fetzer, R. [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany)

2011-12-15

Highlights: Black-Right-Pointing-Pointer Systematic investigation on the solidification microstructure of ternary Al-Sn-Cu immiscible system aided by computational thermodynamics calculations. Black-Right-Pointing-Pointer Comparative study of conventional casting and casting under high-intensity ultrasonic irradiation. Black-Right-Pointing-Pointer Demonstrated the high effectiveness of ultrasound exposure during solidification. Black-Right-Pointing-Pointer Effect of cavitation on nucleation and the relative effects of cavitation and acoustic streaming on the dispersion of Sn-rich liquid phases have been explained from the experimental observation. Cavitation was found to promote fragmentation and dispersion of Sn-rich liquid leading to homogeneous dispersion of refined Sn phase. Microstructural modification was found to be contributed by cavitation and associated shockwave generation while bulk fluid flow under acoustic streaming was found to be less effective on the microstructure evolution. Black-Right-Pointing-Pointer Globular and highly refined {alpha}-Al formed near the radiator through enhanced heterogeneous nucleation in contrast to dendritic {alpha}-Al observed in conventional solidification. - Abstract: A comparative study on the microstructure of four ternary Al-Sn-Cu immiscible alloys, guided by the recent thermodynamic assessment of the system, was carried out with specific focus on the soft Sn particulate distribution in hard Al-rich matrix in the presence and absence of ultrasonic irradiation during solidification. The results clearly demonstrate high effectiveness of ultrasonication in promoting significantly refined and homogeneously dispersed microstructure, probably aided by enhanced nucleation and droplet fragmentation under cavitation. While conventional solidification produced highly segregated Sn phase at the centre and bottom of Sn-rich alloy ingots, ultrasonic treatment produced effective dispersion irrespective of the alloy constitution in

High Efficiency Dye-sensitized Solar Cells Constructed with Composites of TiO2 and the Hot-bubbling Synthesized Ultra-Small SnO2 Nanocrystals.

Science.gov (United States)

Mao, Xiaoli; Zhou, Ru; Zhang, Shouwei; Ding, Liping; Wan, Lei; Qin, Shengxian; Chen, Zhesheng; Xu, Jinzhang; Miao, Shiding

2016-01-13

An efficient photo-anode for the dye-sensitized solar cells (DSSCs) should have features of high loading of dye molecules, favorable band alignments and good efficiency in electron transport. Herein, the 3.4 nm-sized SnO2 nanocrystals (NCs) of high crystallinity, synthesized via the hot-bubbling method, were incorporated with the commercial TiO2 (P25) particles to fabricate the photo-anodes. The optimal percentage of the doped SnO2 NCs was found at ~7.5% (SnO2/TiO2, w/w), and the fabricated DSSC delivers a power conversion efficiency up to 6.7%, which is 1.52 times of the P25 based DSSCs. The ultra-small SnO2 NCs offer three benefits, (1) the incorporation of SnO2 NCs enlarges surface areas of the photo-anode films, and higher dye-loading amounts were achieved; (2) the high charge mobility provided by SnO2 was confirmed to accelerate the electron transport, and the photo-electron recombination was suppressed by the highly-crystallized NCs; (3) the conduction band minimum (CBM) of the SnO2 NCs was uplifted due to the quantum size effects, and this was found to alleviate the decrement in the open-circuit voltage. This work highlights great contributions of the SnO2 NCs to the improvement of the photovoltaic performances in the DSSCs.

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

Science.gov (United States)

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

2015-10-14

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

Zn{sub 2}SnO{sub 4}-SnO{sub 2} heterojunction nanocomposites for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Li Bihui; Luo Lijuan; Xiao Ting; Hu Xiaoyan [Institute of Nano-science and Technology, Central China Normal University, Wuhan, 430079 (China); Lu Lu; Wang, Jianbo [Department of Physics, Wuhan University, Wuhan 430072 (China); Tang Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central China Normal University, Wuhan, 430079 (China)

2011-02-03

Graphical abstract: Display Omitted Research highlights: > The ZTO-SnO{sub 2} based DSSC shows superior photovoltaic performance than single phase ZTO or Pm-ZTO-SnO{sub 2} (physical mixture of ZTO and SnO{sub 2} nanoparticles having the same ZTO/SnO{sub 2} composition) based DSSC. > The obvious improvement in the photovoltaic performance is mainly ascribed to the efficient injected electrons transfer between the two materials via heterojunctions and consequent suppress the recombination. - Abstract: Zn{sub 2}SnO{sub 4}-SnO{sub 2} heterojunction nanocomposites (ZTO-SnO{sub 2}) with high mass amount of ZTO were synthesized by a two-step technique. The route involves firstly the synthesis of monodispersed ZnSn(OH){sub 6} nanocubes with a 50-60 nm edge length as precursors by simple coprecipitation of Na{sub 2}SnO{sub 3}.3H{sub 2}O and ZnCl{sub 2} aqueous solution, assisted by ultrasonic treatment and then followed by calcination of the precursors at 800 deg. C under N{sub 2} atmosphere. The as-synthesized nanoparticles were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Heterojunction between ZTO and SnO{sub 2} nanoparticle was confirmed by the electron energy loss spectroscopy (EELS) elemental mapping and high-resolution TEM (HRTEM). The photovoltaic performance of the ZTO-SnO{sub 2} based DSSC was examined by measuring the J-V curves both in dark and under illumination. The results show that the ZTO-SnO{sub 2} based DSSC exhibits superior photovoltaic performance as compared to the single phase ZTO based DSSCs. Under illumination of AM 1.5 simulated sunlight (100 mW/cm{sup 2}), the open circuit voltage of the cell based on ZTO-SnO{sub 2} is 706 mV, the short-current density is 2.85 mA/cm{sup 2}, and the efficiency is 1.29% which is increased by 43% from 0.90% to 1.29% compared with pure ZTO. The formation of the heterojunctions between ZTO and SnO{sub 2} nanoparticles is believed to reduce

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.

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 of SnO{sub 2}-activated carbon fiber hybrid catalyst for the removal of methyl violet from water

Energy Technology Data Exchange (ETDEWEB)

Li, Jia, E-mail: mse_lij@ujn.edu.cn [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China); Ng, Dickon H.L. [Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong (China); Song, Peng; Kong, Chao; Song, Yi [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China)

2015-04-15

Graphical abstract: - Highlights: • A new biomass route for the synthesis of SnO{sub 2}/ACF hybrid catalyst was proposed. • The original fibrous structure of kapok fiber was retained in the SnO{sub 2}/ACF hybrid catalyst. • SnO{sub 2}/ACF hybrid catalyst exhibited high BET surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). • High microwave-induced catalytic activity for methyl violet degradation was obtained. - Abstract: SnO{sub 2}/activated carbon fiber (ACF) hybrid catalyst was synthesized from kapok precursor via a two-step process involving pore-fabricating and self-assembly of SnO{sub 2} nanoparticles. The morphology and phase structure of the obtained samples were characterized by X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy and N{sub 2} adsorption-desorption isotherm. These results demonstrated that the synthesized SnO{sub 2}/ACF retained the hollow-fiber structure of kapok fibers. SnO{sub 2} nanoparticles dispersed uniformly over the ACF support. The obtained hybrid catalyst showed porous structure with high surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). In addition, the catalytic activities of the obtained samples for methyl violet degradation under microwave irradiation were also evaluated. It was found that the SnO{sub 2}/ACF catalyst exhibited high catalytic activity for methyl violet degradation due to the synergistic effect of microwave and SnO{sub 2}/ACF catalyst.

Contribution to the design of superconducting Nb3Sn dipole windings for particle accelerator

International Nuclear Information System (INIS)

Felice, H.

2006-10-01

Improvement of particle accelerators relies on complex technologies such as the design and fabrication of superconducting magnets. A key parameter in magnet design is the mechanical pre-stress, applied at room temperature to insure compression of the coil during excitation. In dipole magnets, high field and high mechanical stresses in windings combined with the Nb 3 Sn stress sensitivity ask the question of the limit of the mechanical stress that the Nb 3 Sn can undergo without degradation. This limit estimated around 150 MPa is still discussed and has to be investigated. Whatever its value, preliminary studies show that conventional cosine theta design induces mechanical stresses (> 200 MPa) in large aperture (> 130 mm) and high field configurations, which underscore the need of alternative coil arrangements. The first part of this thesis gives an introduction to the issues and challenges encountered by the designers of superconducting ma nets. The second part is devoted to the study of large aperture (88, 130 and 160 mm) and high field (13 T) dipoles based on intersecting ellipses. After a theoretical study, a 2D magnetic design is detailed for each aperture and a mechanical study is developed for the 130 mm aperture dipole. In the last part, an experimental device dedicated to the study of the influence of the pre-stress on the training of sub-scale Nb 3 Sn dipole and to the investigation of the mechanical stress limit is presented. The design of this magnet is detailed and the result of the first test carried out with the structure is reported. (author)

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

Development and test of Nb(3)Sn cos-theta dipoles based on PIT strands

Energy Technology Data Exchange (ETDEWEB)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chichili, D.R.; Elementi, L.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Yamada, R.; /Fermilab

2004-11-01

Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb{sub 3}Sn strands produced using different technologies. Two 1-m long models--mirror configuration and dipole magnet--were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb{sub 3}Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing.

SnS2 nanosheets arrays sandwiched by N-doped carbon and TiO2 for high-performance Na-ion storage

Directory of Open Access Journals (Sweden)

Weina Ren

2018-01-01

Full Text Available In this paper, SnS2 nanosheets arrays sandwiched by porous N-doped carbon and TiO2 (TiO2@SnS2@N-C on flexible carbon cloth are prepared and tested as a free-standing anode for high-performance sodium ion batteries. The as-obtained TiO2@SnS2@N-C composite delivers a remarkable capacity performance (840 mA h g−1 at a current density of 200 mA g−1, excellent rate capability and long-cycling life stability (293 mA h g−1 at 1 A g−1 after 600 cycles. The excellent electrochemical performance can be attributed to the synergistic effect of each component of the unique hybrid structure, in which the SnS2 nanosheets with open framworks offer high capacity, while the porous N-doped carbon nanoplates arrays on flexible carbon cloth are able to improve the conductivity and the TiO2 passivation layer can keep the structure integrity of SnS2 nanosheets.

Quench performance of Nb3Sn cos-theta coils made of 108/127 RRP strands

International Nuclear Information System (INIS)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.

2007-01-01

A series of 1-m long Nb 3 Sn dipole models has been built at Fermilab in an attempt to refine the wind-and-react technology for Nb3Sn accelerator magnets. Three models made with Powder-in-Tube Nb 3 Sn strand reached their design field of 10 T demonstrating a good reproducibility of magnet quench performance and field quality. Recently a new dipole 'mirror' model based on Nb 3 Sn coil made of improved Restack Rod Process strand was constructed and tested reaching the maximum field above 11 T. This paper describes the parameters of the RRP strand and cable used as well as the design, fabrication and test results of this magnet

Thermal fluctuations in the classical superconductor Nb{sub 3}Sn from high-resolution specific-heat measurements

Energy Technology Data Exchange (ETDEWEB)

Lortz, Rolf [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland)], E-mail: Rolf.Lortz@physics.unige.ch; Wang Yuxing; Junod, Alain [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Toyota, Naoki [Physics Department, Graduate School of Science, Tohoku University, 980-8571 Sendai (Japan)

2007-09-01

The range of thermal fluctuations in 'classical' bulk superconductors is extremely small and especially in low-fields hardly experimentally accessible. With a new type of calorimeter we were able to detect a tiny lambda anomaly in the specific-heat of the superconductor Nb{sub 3}Sn within a narrow temperature range around the H{sub c2} line. We show that the evolution of the anomaly as a function of magnetic field follows scaling laws expected in the presence of critical thermal fluctuations.

A graphene–SnO_2–TiO_2 ternary nanocomposite electrode as a high stability lithium-ion anode material

International Nuclear Information System (INIS)

Liang, Jicai; Wang, Juan; Zhou, Meixin; Li, Yi; Wang, Xiaofeng; Yu, Kaifeng

2016-01-01

In this work, a solvothermal method combined with a hydrothermal two-step method is developed to synthesize graphene–SnO_2–TiO_2 ternary nanocomposite, in which the nanometer-sized TiO_2 and SnO_2 nanoparticles form in situ uniformly anchored on the surface of graphene sheets, as high stability and capacity lithium-ion anode materials. Compared to graphene–TiO_2, bulk TiO_2 and grapheme–SnO_2 composites, the as-prepared nanocomposite delivers a superior rate performance of 499.3 mAhg"−"1 at 0.2 C and an outstanding stability cycling capability (1073.4 mAhg"−"1 at 0.2 C after 50 cycles), due to the synergistic effects contributed from individual components, for example, high specific capacity of SnO_2, excellent conductivity of 3D graphene networks. - Graphical abstract: Graphene–SnO_2–TiO_2 nanocomposite is synthesized by a hydrothermal two-step method. The composite exhibits higher reversible capacity and better cycle/rate performance due to the unique structure. - Highlights: • We have synthesized a graphene–SnO_2–TiO_2 nanocomposite by a two-step method to improve the cycling performance. • Graphene–SnO_2–TiO_2 nanocomposite is synthesized by a hydrothermal two-step method. • The composite exhibits higher reversible capacity and better cycle/rate performance due to the unique structure.

Solid Liquid Interdiffusion Bonding of (Pb, Sn)Te Thermoelectric Modules with Cu Electrodes Using a Thin-Film Sn Interlayer

Science.gov (United States)

Chuang, T. H.; Lin, H. J.; Chuang, C. H.; Yeh, W. T.; Hwang, J. D.; Chu, H. S.

2014-12-01

A (Pb, Sn)Te thermoelectric element plated with a Ni barrier layer and a Ag reaction layer has been joined with a Cu electrode coated with Ag and Sn thin films using a solid-liquid interdiffusion bonding method. This method allows the interfacial reaction between Ag and Sn such that Ag3Sn intermetallic compounds form at low temperature and are stable at high temperature. In this study, the bonding strength was about 6.6 MPa, and the specimens fractured along the interface between the (Pb, Sn)Te thermoelectric element and the Ni barrier layer. Pre-electroplating a film of Sn with a thickness of about 1 μm on the thermoelectric element and pre-heating at 250°C for 3 min ensures the adhesion between the thermoelectric material and the Ni barrier layer. The bonding strength is thus increased to a maximal value of 12.2 MPa, and most of the fractures occur inside the thermoelectric material. During the bonding process, not only the Ag3Sn intermetallics but also Cu6Sn5 forms at the Ag3Sn/Cu interface, which transforms into Cu3Sn with increases in the bonding temperature or bonding time.

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

Science.gov (United States)

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

2008-07-04

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

Control of Ambipolar Transport in SnO Thin-Film Transistors by Back-Channel Surface Passivation for High Performance Complementary-like Inverters.

Science.gov (United States)

Luo, Hao; Liang, Lingyan; Cao, Hongtao; Dai, Mingzhi; Lu, Yicheng; Wang, Mei

2015-08-12

For ultrathin semiconductor channels, the surface and interface nature are vital and often dominate the bulk properties to govern the field-effect behaviors. High-performance thin-film transistors (TFTs) rely on the well-defined interface between the channel and gate dielectric, featuring negligible charge trap states and high-speed carrier transport with minimum carrier scattering characters. The passivation process on the back-channel surface of the bottom-gate TFTs is indispensable for suppressing the surface states and blocking the interactions between the semiconductor channel and the surrounding atmosphere. We report a dielectric layer for passivation of the back-channel surface of 20 nm thick tin monoxide (SnO) TFTs to achieve ambipolar operation and complementary metal oxide semiconductor (CMOS) like logic devices. This chemical passivation reduces the subgap states of the ultrathin channel, which offers an opportunity to facilitate the Fermi level shifting upward upon changing the polarity of the gate voltage. With the advent of n-type inversion along with the pristine p-type conduction, it is now possible to realize ambipolar operation using only one channel layer. The CMOS-like logic inverters based on ambipolar SnO TFTs were also demonstrated. Large inverter voltage gains (>100) in combination with wide noise margins are achieved due to high and balanced electron and hole mobilities. The passivation also improves the long-term stability of the devices. The ability to simultaneously achieve field-effect inversion, electrical stability, and logic function in those devices can open up possibilities for the conventional back-channel surface passivation in the CMOS-like electronics.

Synthesis and fundamental properties of stable Ph(3)SnSiH(3) and Ph(3)SnGeH(3) hydrides: model compounds for the design of Si-Ge-Sn photonic alloys.

Science.gov (United States)

Tice, Jesse B; Chizmeshya, Andrew V G; Groy, Thomas L; Kouvetakis, John

2009-07-06

The compounds Ph(3)SnSiH(3) and Ph(3)SnGeH(3) (Ph = C(6)H(5)) have been synthesized as colorless solids containing Sn-MH(3) (M = Si, Ge) moieties that are stable in air despite the presence of multiple and highly reactive Si-H and Ge-H bonds. These molecules are of interest since they represent potential model compounds for the design of new classes of IR semiconductors in the Si-Ge-Sn system. Their unexpected stability and high solubility also makes them a safe, convenient, and potentially useful delivery source of -SiH(3) and -GeH(3) ligands in molecular synthesis. The structure and composition of both compounds has been determined by chemical analysis and a range of spectroscopic methods including multinuclear NMR. Single crystal X-ray structures were determined and indicated that both compounds condense in a Z = 2 triclinic (P1) space group with lattice parameters (a = 9.7754(4) A, b = 9.8008(4) A, c = 10.4093(5) A, alpha = 73.35(10)(o), beta = 65.39(10)(o), gamma = 73.18(10)(o)) for Ph(3)SnSiH(3) and (a = 9.7927(2) A, b = 9.8005(2) A, c = 10.4224(2) A, alpha = 74.01(3)(o), beta = 65.48(3)(o), gamma = 73.43(3)(o)) for Ph(3)SnGeH(3). First principles density functional theory simulations are used to corroborate the molecular structures of Ph(3)SnSiH(3) and Ph(3)SnGeH(3), gain valuable insight into the relative stability of the two compounds, and provide correlations between the Si-Sn and Ge-Sn bonds in the molecules and those in tetrahedral Si-Ge-Sn solids.

Photoluminescence and electroluminescence from Ge/strained GeSn/Ge quantum wells

Energy Technology Data Exchange (ETDEWEB)

Lin, Chung-Yi; Chang, Chih-Chiang [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Huang, Chih-Hsiung; Huang, Shih-Hsien [Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liu, C. W., E-mail: chee@cc.ee.ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); National Nano Device Labs, Hsinchu 30077, Taiwan (China); Huang, Yi-Chiau; Chung, Hua; Chang, Chorng-Ping [Applied Materials Inc., Sunnyvale, California 94085 (United States)

2016-08-29

Ge/strained GeSn/Ge quantum wells are grown on a 300 mm Si substrate by chemical vapor deposition. The direct bandgap emission from strained GeSn is observed in the photoluminescence spectra and is enhanced by Al{sub 2}O{sub 3}/SiO{sub 2} passivation due to the field effect. The electroluminescence of the direct bandgap emission of strained GeSn is also observed from the Ni/Al{sub 2}O{sub 3}/GeSn metal-insulator-semiconductor tunneling diodes. Electroluminescence is a good indicator of GeSn material quality, since defects in GeSn layers degrade the electroluminescence intensity significantly. At the accumulation bias, the holes in the Ni gate electrode tunnel to the strained n-type GeSn layer through the ultrathin Al{sub 2}O{sub 3} and recombine radiatively with electrons. The emission wavelength of photoluminescence and electroluminescence can be tuned by the Sn content.

Highly sensitive formaldehyde resistive sensor based on a single Er-doped SnO_2 nanobelt

International Nuclear Information System (INIS)

Li, Shuanghui; Liu, Yingkai; Wu, Yuemei; Chen, Weiwu; Qin, Zhaojun; Gong, Nailiang; Yu, Dapeng

2016-01-01

SnO_2 nanobelts (SnO_2 NBs) and Er"3"+-doped SnO_2 nanobelts (Er–SnO_2 NBs) were synthesized by thermal evaporation. The obtained samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersion spectrometer (EDS), and X-ray photoelectron spectrometer (XPS). It is found that Er–SnO_2 NBs have a good morphology with smooth surface and their thickness are about 30 nm, widths between 200 nm and 600 nm, and lengths 30–80 mm. The nanobelts with good morphology were taken to develop sensors based on a single Er–SnO_2 NB/SnO_2 NB for studying sensitive properties. The results reveal that the response of a single Er–SnO_2 nanobelt device is 9 to the formaldehyde gas with a shorter response (recovery time) of 17 (25) s.

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.

Sensors based on mesoporous SnO{sub 2}-CuWO{sub 4} with high selective sensitivity to H{sub 2}S at low operating temperature

Energy Technology Data Exchange (ETDEWEB)

Stanoiu, Adelina; Simion, Cristian E. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Calderon-Moreno, Jose Maria; Osiceanu, Petre [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania); Florea, Mihaela [University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest (Romania); National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Teodorescu, Valentin S. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Somacescu, Simona, E-mail: somacescu.simona@gmail.com [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania)

2017-06-05

Highlights: • Mesoporous SnO{sub 2}-CuWO{sub 4} obtained by an inexpensive synthesis route. • Powders characterization performed by a variety of complementary techniques. • SnO{sub 2}-CuWO{sub 4} layers with high selective sensitivity to H{sub 2}S. • Low operating temperature and relative humidity influences. - Abstract: Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H{sub 2}S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO{sub 2}-CuWO{sub 4} with selective sensitivity to H{sub 2}S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N{sub 2} adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al{sub 2}O{sub 3} substrates. The sensor signals towards H{sub 2}S exposure at low operating temperature (100 °C) reaches values from 10{sup 5} (for SnWCu600) to 10{sup 6} (for SnWCu800) over the full range of concentrations (5–30 ppm). The recovery processes were induced by a short temperature trigger of 500 °C. The selective sensitivity was underlined with respect to the H{sub 2}S, relative to other potential pollutants and relative humidity (10–70% RH).

STRESS a SN survey at ESO

Science.gov (United States)

Botticella, M. T.

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

Anchoring ultrafine Pd nanoparticles and SnO2 nanoparticles on reduced graphene oxide for high-performance room temperature NO2 sensing.

Science.gov (United States)

Wang, Ziying; Zhang, Tong; Zhao, Chen; Han, Tianyi; Fei, Teng; Liu, Sen; Lu, Geyu

2018-03-15

In this paper, we demonstrate room-temperature NO 2 gas sensors using Pd nanoparticles (NPs) and SnO 2 NPs decorated reduced graphene oxide (Pd-SnO 2 -RGO) hybrids as sensing materials. It is found that ultrafine Pd NPs and SnO 2 NPs with particle sizes of 3-5 nm are attached to RGO nanosheets. Compared to SnO 2 -RGO hybrids, the sensor based on Pd-SnO 2 -RGO hybrids exhibited higher sensitivity at room temperature, where the response to 1 ppm NO 2 was 3.92 with the response time and recovery time being 13 s and 105 s. Moreover, such sensor exhibited excellent selectivity, and low detection limit (50 ppb). In addition to high transport capability of RGO as well as excellent NO 2 adsorption ability derived from ultrafine SnO 2 NPs and Pd NPs, the superior sensing performances of the hybrids were attributed to the synergetic effect of Pd NPs, SnO 2 NPs and RGO. Particularly, the excellent sensing performances were related to high conductivity and catalytic activity of Pd NPs. Finally, the sensing mechanism for NO 2 sensing and the reason for enhanced sensing performances by introduction of Pd NPs are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

Energy Technology Data Exchange (ETDEWEB)

Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

2016-08-15

The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

High energy emission of supernova sn 1987a. Cosmic rays acceleration in mixed shocks

International Nuclear Information System (INIS)

Lehoucq, Roland

1992-01-01

In its first part, this research thesis reports the study of the high energy emission of the sn 1987 supernova, based on a Monte Carlo simulation of the transfer of γ photons emitted during disintegration of radioactive elements (such as "5"6Ni, "5"6Co, "5"7Co and "4"4Ti) produced during the explosion. One of the studied problems is the late evolution (beyond 1200 days) of light curvature which is very different when it is powered by the radiation of a central object or by radioactivity. The second part reports the study of acceleration of cosmic rays in two-fluid shock waves in order to understand the different asymmetries noticed in hot spots of extragalactic radio-sources. This work comprises the resolution of structure equations of a shock made of a conventional fluid and a relativistic one, in presence or absence of a magnetic field [fr

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)

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Quench performance of Nb3Sn cos-theta coils made of 108/127 RRP strands

Energy Technology Data Exchange (ETDEWEB)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab

2007-07-01

A series of 1-m long Nb{sub 3}Sn dipole models has been built at Fermilab in an attempt to refine the wind-and-react technology for Nb3Sn accelerator magnets. Three models made with Powder-in-Tube Nb{sub 3}Sn strand reached their design field of 10 T demonstrating a good reproducibility of magnet quench performance and field quality. Recently a new dipole 'mirror' model based on Nb{sub 3}Sn coil made of improved Restack Rod Process strand was constructed and tested reaching the maximum field above 11 T. This paper describes the parameters of the RRP strand and cable used as well as the design, fabrication and test results of this magnet.

Polymer ferroelectric field-effect memory device with SnO channel layer exhibits record hole mobility

KAUST Repository

Caraveo-Frescas, Jesus Alfonso; Khan, M. A.; Alshareef, Husam N.

2014-01-01

Here we report for the first time a hybrid p-channel polymer ferroelectric field-effect transistor memory device with record mobility. The memory device, fabricated at 200C on both plastic polyimide and glass substrates, uses ferroelectric polymer P(VDF-TrFE) as the gate dielectric and transparent p-type oxide (SnO) as the active channel layer. A record mobility of 3.3 cm 2V-1s-1, large memory window (~16 V), low read voltages (~-1 V), and excellent retention characteristics up to 5000 sec have been achieved. The mobility achieved in our devices is over 10 times higher than previously reported polymer ferroelectric field-effect transistor memory with p-type channel. This demonstration opens the door for the development of non-volatile memory devices based on dual channel for emerging transparent and flexible electronic devices.

Polymer ferroelectric field-effect memory device with SnO channel layer exhibits record hole mobility

KAUST Repository

Caraveo-Frescas, Jesus Alfonso

2014-06-10

Here we report for the first time a hybrid p-channel polymer ferroelectric field-effect transistor memory device with record mobility. The memory device, fabricated at 200C on both plastic polyimide and glass substrates, uses ferroelectric polymer P(VDF-TrFE) as the gate dielectric and transparent p-type oxide (SnO) as the active channel layer. A record mobility of 3.3 cm 2V-1s-1, large memory window (~16 V), low read voltages (~-1 V), and excellent retention characteristics up to 5000 sec have been achieved. The mobility achieved in our devices is over 10 times higher than previously reported polymer ferroelectric field-effect transistor memory with p-type channel. This demonstration opens the door for the development of non-volatile memory devices based on dual channel for emerging transparent and flexible electronic devices.

Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion.

Science.gov (United States)

Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

2017-11-16

Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm³, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg₂Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy.

Centrifugal extraction of highly enriched tin isotopes and increase of specific activity of the radionuclide 119mSn on the gas centrifuge cascade

International Nuclear Information System (INIS)

Suvorov, I.A.; Tcheltsov, A.N.; Sosnin, L.Yu.; Sazikin, A.A.; Rudnev, A.I.

2002-01-01

This work contains the results of research on centrifugal enrichment of 118 Sn isotope followed by irradiation and, finally, a second centrifugal enrichment to produce high specific activity 119m Sn. Non-steady-state separation methods were used for the effective extraction of the radionuclide 119m Sn from the irradiated target. As a result of this work, radiation sources based on 119m Sn were obtained with a specific activity of 500 mCi/g. This is 100 times greater than the specific activity obtained after irradiation in the reactor alone. In addition, the sources had an previously unattainable radio-purity ratio of 113 Sn/ 119m Sn of approximately 10 -6

Influence of grain size and upper critical magnetic field on global pinning force of bronze-processed Nb/sub 3/Sn compound

International Nuclear Information System (INIS)

Ochiai, S.; Osamura, K.

1986-01-01

In order to know the dependency of global pinning force of Nb/sub 3/Sn compound on grain size and upper critical magnetic field, the global pinning force was measured at 3-15 T using bronze-processed multifilamentary composites. The grain size and upper critical magnetic field were varied by two types of annealing treatment: one is the isothermal annealing at 873, 973 and 1073 K up to 1730 ks and another is the two-stage annealing (low temperature annealing to form fine grains at 873 K for 1730 ks + high temperature annealing to raise upper critical magnetic field at 1073 K up to 18 ks). In the case of isothermal annealing treatment, both of grain size and upper critical magnetic field increased with increasing annealing temperature and time except for the annealing treatments at high temperature for prolonged times. In the case of two-stage annealing, both of them increased with second stage annealing time. The increase in grain size led to decrease in the pinning force but the increase in upper critical magnetic field to increase in it. From the analysis of the present data based on the Suenaga's speculation concerning with the density of pinning site and the Kramer's equation, it was suggested that the pinning force is, to a first approximation, proportional to the product of inverse grain size and (1-h)/sup 2/h/sup 1/2/ where h is the reduced magnetic field

Transparent p-type SnO nanowires with unprecedented hole mobility among oxide semiconductors

KAUST Repository

Caraveo-Frescas, J. A.

2013-11-25

p-type tin monoxide (SnO) nanowire field-effect transistors with stable enhancement mode behavior and record performance are demonstrated at 160 °C. The nanowire transistors exhibit the highest field-effect hole mobility (10.83 cm2 V−1 s−1) of any p-type oxide semiconductor processed at similar temperature. Compared to thin film transistors, the SnO nanowire transistors exhibit five times higher mobility and one order of magnitude lower subthreshold swing. The SnO nanowire transistors show three times lower threshold voltages (−1 V) than the best reported SnO thin film transistors and fifteen times smaller than p-type Cu 2O nanowire transistors. Gate dielectric and process temperature are critical to achieving such performance.

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.

3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam

Science.gov (United States)

Um, Ji Hyun; Choi, Myounggeun; Park, Hyeji; Cho, Yong-Hun; Dunand, David C.; Choe, Heeman; Sung, Yung-Eun

2016-01-01

A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume changes in high-capacity anode materials during cycling. Here we report the first demonstration of a SnO2-coated macroporous Cu foam anode by employing a facile and scalable combination of directional freeze-casting and sol-gel coating processes. The three-dimensional interconnected anode is composed of aligned microscale channels separated by SnO2-coated Cu walls and much finer micrometer pores, adding to surface area and providing space for volume expansion of SnO2 coating layer. With this anode, we achieve a high reversible capacity of 750 mAh g−1 at current rate of 0.5 C after 50 cycles and an excellent rate capability of 590 mAh g−1 at 2 C, which is close to the best performance of Sn-based nanoscale material so far. PMID:26725652

Superior cycle performance and high reversible capacity of SnO2/graphene composite as an anode material for lithium-ion batteries.

Science.gov (United States)

Liu, Lilai; An, Maozhong; Yang, Peixia; Zhang, Jinqiu

2015-03-12

SnO2/graphene composite with superior cycle performance and high reversible capacity was prepared by a one-step microwave-hydrothermal method using a microwave reaction system. The SnO2/graphene composite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscopy and high resolution transmission electron microscopy. The size of SnO2 grains deposited on graphene sheets is less than 3.5 nm. The SnO2/graphene composite exhibits high capacity and excellent electrochemical performance in lithium-ion batteries. The first discharge and charge capacities at a current density of 100 mA g(-1) are 2213 and 1402 mA h g(-1) with coulomb efficiencies of 63.35%. The discharge specific capacities remains 1359, 1228, 1090 and 1005 mA h g(-1) after 100 cycles at current densities of 100, 300, 500 and 700 mA g(-1), respectively. Even at a high current density of 1000 mA g(-1), the first discharge and charge capacities are 1502 and 876 mA h g(-1), and the discharge specific capacities remains 1057 and 677 mA h g(-1) after 420 and 1000 cycles, respectively. The SnO2/graphene composite demonstrates a stable cycle performance and high reversible capacity for lithium storage.

Multifilamentary Cu-Nb3Sn superconductor wires

International Nuclear Information System (INIS)

Rodrigues, D.; Pinatti, D.G.

1990-01-01

This paper reports on one of the main technological problems concerning Nb 3 Sn superconducting wires production which is the optimization of heat treatments for the formation of the A-15 intermetallic compound. At the present work, Nb 3 Sn superconducting wire is produced by solid-liquid diffusion method which increases considerably the critical current values of the superconductor. Through this method, niobium, copper and Sn 7% wt Cu alloy are kept in the pure state. Thus, the method dispenses intermediate heat treatments of recrystallization during the manufacturing process of the wire. After the wire was ready, optimization work of heat treatments was accomplished aiming to obtain its best superconducting characteristics, Measurement of critical temperature, critical current versus magnetic field, normal and at room temperature resistivity were performed, as well as scanning electron microscopy for determination of Nb 3 Sn layers and transmission electron microscopy measurements of redetermining the grain sizes in Nb 3 Sn formed in each treatment. It was obtained critical current densities of 1.8 x 10 6 A/cm 2 in the Nb 3 Sn layer, at 10 Teslas and 4.2 K. The samples were analyzed by employing the superconducting collective flux pinning theories and a satisfactory agreement between the experimental and theoretical data was attained. The production process and the small size of the filaments used made a successful optimization of the wire possible

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

Experimental study of the Cu-Al-Sn phase equilibria, close to the copper zone

Directory of Open Access Journals (Sweden)

Soares D.F.

2017-01-01

Full Text Available The ternary Cu-Al-Sn phase diagram is the base for several important types of alloys, with relevant industrial interest and applications. The knowledge of the melting/solidification alloys characteristics are determinant for their preparation and properties control. However, there is a lack of experimental information on the ternary phase diagram, at high temperature. In this work, several alloys, with high copper content and additions of Al, up to 10%, and Sn, up to 14% (in wt%, were studied by thermal analysis and by isothermal phase equilibria determination. The alloys liquidus and solidus lines and the binary α + β phase field, at 800°C, are presented for the studied range of compositions.

Tin (Sn) for enhancing performance in silicon CMOS

KAUST Repository

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

2013-01-01

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

Tin (Sn) for enhancing performance in silicon CMOS

KAUST Repository

Hussain, Aftab M.

2013-10-01

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

GeSn-on-insulator substrate formed by direct wafer bonding

Energy Technology Data Exchange (ETDEWEB)

Lei, Dian; Wang, Wei; Gong, Xiao, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org; Yeo, Yee-Chia, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Lee, Kwang Hong; Wang, Bing [Low Energy Electronic Systems (LEES), Singapore MIT Alliance for Research and Technology (SMART), 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602 (Singapore); Bao, Shuyu [Low Energy Electronic Systems (LEES), Singapore MIT Alliance for Research and Technology (SMART), 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Tan, Chuan Seng [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

2016-07-11

GeSn-on-insulator (GeSnOI) on Silicon (Si) substrate was realized using direct wafer bonding technique. This process involves the growth of Ge{sub 1-x}Sn{sub x} layer on a first Si (001) substrate (donor wafer) followed by the deposition of SiO{sub 2} on Ge{sub 1-x}Sn{sub x}, the bonding of the donor wafer to a second Si (001) substrate (handle wafer), and removal of the Si donor wafer. The GeSnOI material quality is investigated using high-resolution transmission electron microscopy, high-resolution X-ray diffraction (HRXRD), atomic-force microscopy, Raman spectroscopy, and spectroscopic ellipsometry. The Ge{sub 1-x}Sn{sub x} layer on GeSnOI substrate has a surface roughness of 1.90 nm, which is higher than that of the original Ge{sub 1-x}Sn{sub x} epilayer before transfer (surface roughness is 0.528 nm). The compressive strain of the Ge{sub 1-x}Sn{sub x} film in the GeSnOI is as low as 0.10% as confirmed using HRXRD and Raman spectroscopy.

Pt-Richcore/Sn-Richsubsurface/Ptskin Nanocubes As Highly Active and Stable Electrocatalysts for the Ethanol Oxidation Reaction.

Science.gov (United States)

Rizo, Rubén; Arán-Ais, Rosa M; Padgett, Elliot; Muller, David A; Lázaro, Ma Jesús; Solla-Gullón, José; Feliu, Juan M; Pastor, Elena; Abruña, Héctor D

2018-03-14

Direct ethanol fuel cells are one of the most promising electrochemical energy conversion devices for portable, mobile and stationary power applications. However, more efficient and stable and less expensive electrocatalysts are still required. Interestingly, the electrochemical performance of the electrocatalysts toward the ethanol oxidation reaction can be remarkably enhanced by exploiting the benefits of structural and compositional sensitivity and control. Here, we describe the synthesis, characterization, and electrochemical behavior of cubic Pt-Sn nanoparticles. The electrochemical activity of the cubic Pt-Sn nanoparticles was found to be about three times higher than that obtained with unshaped Pt-Sn nanoparticles and six times higher than that of Pt nanocubes. In addition, stability tests indicated the electrocatalyst preserves its morphology and remains well-dispersed on the carbon support after 5000 potential cycles, while a cubic (pure) Pt catalyst exhibited severe agglomeration of the nanoparticles after a similar stability testing protocol. A detailed analysis of the elemental distribution in the nanoparticles by STEM-EELS indicated that Sn dissolves from the outer part of the shell after potential cycling, forming a ∼0.5 nm Pt skin. This particular atomic composition profile having a Pt-rich core, a Sn-rich subsurface layer, and a Pt-skin surface structure is responsible for the high activity and stability.

Metal-Organic Frameworks Derived Okra-like SnO2 Encapsulated in Nitrogen-Doped Graphene for Lithium Ion Battery.

Science.gov (United States)

Zhou, Xiangyang; Chen, Sanmei; Yang, Juan; Bai, Tao; Ren, Yongpeng; Tian, Hangyu

2017-04-26

A facile process is developed to prepare SnO 2 -based composites through using metal-organic frameworks (MOFs) as precursors. The nitrogen-doped graphene wrapped okra-like SnO 2 composites (SnO 2 @N-RGO) are successfully synthesized for the first time by using Sn-based metal-organic frameworks (Sn-MOF) as precursors. When utilized as an anode material for lithium-ion batteries, the SnO 2 @N-RGO composites possess a remarkably superior reversible capacity of 1041 mA h g -1 at a constant current of 200 mA g -1 after 180 charge-discharge processes and excellent rate capability. The excellent performance can be primarily ascribed to the unique structure of 1D okra-like SnO 2 in SnO 2 @N-RGO which are actually composed of a great number of SnO 2 primary crystallites and numerous well-defined internal voids, can effectively alleviate the huge volume change of SnO 2 , and facilitate the transport and storage of lithium ions. Besides, the structural stability acquires further improvement when the okra-like SnO 2 are wrapped by N-doped graphene. Similarly, this synthetic strategy can be employed to synthesize other high-capacity metal-oxide-based composites starting from various metal-organic frameworks, exhibiting promising application in novel electrode material field of lithium-ion batteries.

Design and synthesis of porous nano-sized Sn@C/graphene electrode material with 3D carbon network for high-performance lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Lian, Peichao, E-mail: lianpeichao@126.com [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Wang, Jingyi [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Cai, Dandan; Liu, Guoxue [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Wang, Yingying [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Wang, Haihui, E-mail: hhwang@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

2014-08-01

Highlights: • Porous nano-sized Sn@C/graphene electrode material was designed and prepared. • The preparation method presented here can avoid the agglomeration of nanoparticles. • The prepared Sn@C/graphene electrode material exhibits outstanding cyclability. - Abstract: Tin is a promising high-capacity anode material for lithium-ion batteries, but it usually suffers from the problem of poor cycling stability due to the large volume change during the charge–discharge process. In this article, porous nano-sized Sn@C/graphene electrode material with three-dimensional carbon network was designed and prepared. Reducing the size of the Sn particles to nanoscale can mitigate the absolute strain induced by the large volume change during lithiation–delithiation process, and retard particle pulverization. The porous structure can provide a void space, which helps to accommodate the volume changes of the Sn nanoparticles during the lithium uptake-release process. The carbon shell can avoid the aggregation of the Sn nanoparticles on the same piece of graphene and detachment of the pulverized Sn particles during the charge–discharge process. The 3D carbon network consisted of graphene sheets and carbon shells can not only play a structural buffering role in minimizing the mechanical stress caused by the volume change of Sn, but also keep the overall electrode highly conductive during the lithium uptake-release process. As a result, the as-prepared Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries exhibited outstanding cyclability. The reversible specific capacity is almost constant from the tenth cycle to the fiftieth cycle, which is about 600 mA h g{sup −1}. The strategy presented in this work may be extended to improve the cycle performances of other high-capacity electrode materials with large volume variations during charge–discharge processes.

Hollow Amorphous MnSnO3 Nanohybrid with Nitrogen-Doped Graphene for High-Performance Lithium Storage

International Nuclear Information System (INIS)

Liu, Peng; Hao, Qingli; Xia, Xifeng; Lei, Wu; Xia, Hui; Chen, Ziyang; Wang, Xin

2016-01-01

Graphical abstract: A novel hybrid of hollow amorphous MnSnO 3 nanoparticles and nitrogen-doped reduced graphene oxide was fabricated. The unique structure and well-combination of both components account for the ultra long-term cyclic life with high reversible capacity of 610 mAh g −1 over 1000 cycles at 400 mA g −1 . - Highlights: • Novel hybrid of MnSnO 3 and nitrogen-doped reduced graphene oxide was fabricated. • The MnSnO 3 nanoparticles possess amorphous and hollow structure in the composite. • The excellent electrochemical performance benefits from unique nanostructure. • The reversible capacity of as-prepared hybrid is 610 mAh g −1 after 1000 cycles. • A long-term life with 97.3% capacity retention over 1000 cycles was obtained. - Abstract: Tin-based metal oxides usually suffer from severe capacity fading resulting from aggregation and considerable volume variation during the charge/discharge process in lithium ion batteries. In this work, a novel nanocomposite (MTO/N-RGO) of hollow amorphous MnSnO 3 (MTO) nanoparticles and nitrogen-doped reduced graphene oxide (N-RGO) has been designed and synthesized by a two-step method. Firstly, the nitrogen-doped graphene nanocomposite (MTO/N-RGO-P) with MnSn(OH) 6 crystal nanoparticles was synthesized by a facile solvothermal method. Subsequently, the MTO/N-RGO nanocomposite was obtained through the post heat treatment of MTO/N-RGO-P. The designed heterostructure and well-combination of the hollow amorphous MTO and N-RGO matrix can accelerate the ionic and electronic transport, and simultaneously accommodate the aggregation and volume variation of MTO nanoparticles during the lithiation–delithiation cycles. The as-prepared hybrid of MTO and N-RGO (MTO/N-RGO) exhibits a high reversible capacity of 707 mAh g −1 after 110 cycles at 200 mA g −1 , superior rate capability, and long-term cyclic life with high capacity of 610 mAh g −1 over 1000 cycles at 400 mA g −1 . Superior capacity retention of

Au–Sn bonding material for the assembly of power integrated circuit module

Energy Technology Data Exchange (ETDEWEB)

Zhu, Z.X.; Li, C.C. [Department of Materials Science & Engineering, National Taiwan University, Taipei, Taiwan (China); Liao, L.L.; Liu, C.K. [Electronic and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Kao, C.R., E-mail: crkao@ntu.edu.tw [Department of Materials Science & Engineering, National Taiwan University, Taipei, Taiwan (China)

2016-06-25

Insulated gate bipolar transistor (IGBT) chips are the key components in high-temperature power electronic modules, which have to efficiently convert electricity between direct and alternating current. In this study, the eutectic Au–Sn (20 wt.% Sn) is successfully used to assemble IGBT chips and direct-bond-copper substrates by using solid liquid interdiffusion (SLID) bonding. During subsequent isothermal aging at 150, 200, and 240 °C, the microstructure evolution and growth kinetics of intermetallic compounds are investigated. Excellent thermal stability and mechanical strength are observed. It is concluded that the eutectic Au–Sn solder is ideal to assemble high-temperature IGBT by using the SLID process. - Highlights: • Au–20Sn serves as a promising bonding material for IGBT operating at T < 519 °C. • The Au–20Sn reacted with Ni to form (Ni,Au){sub 3}Sn{sub 2}/(Au{sub 5}Sn + AuSn)/(Ni,Au){sub 3}Sn{sub 2}. • Once the AuSn was nearly exhausted, the whole joint could withstand higher temperatures. • A cost-effective way for long-term operations at high temperature.

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.

Reduced SnO2 Porous Nanowires with a High Density of Grain Boundaries as Catalysts for Efficient Electrochemical CO2 -into-HCOOH Conversion.

Science.gov (United States)

Kumar, Bijandra; Atla, Veerendra; Brian, J Patrick; Kumari, Sudesh; Nguyen, Tu Quang; Sunkara, Mahendra; Spurgeon, Joshua M

2017-03-20

Electrochemical conversion of CO 2 into energy-dense liquids, such as formic acid, is desirable as a hydrogen carrier and a chemical feedstock. SnO x is one of the few catalysts that reduce CO 2 into formic acid with high selectivity but at high overpotential and low current density. We show that an electrochemically reduced SnO 2 porous nanowire catalyst (Sn-pNWs) with a high density of grain boundaries (GBs) exhibits an energy conversion efficiency of CO 2 -into-HCOOH higher than analogous catalysts. HCOOH formation begins at lower overpotential (350 mV) and reaches a steady Faradaic efficiency of ca. 80 % at only -0.8 V vs. RHE. A comparison with commercial SnO 2 nanoparticles confirms that the improved CO 2 reduction performance of Sn-pNWs is due to the density of GBs within the porous structure, which introduce new catalytically active sites. Produced with a scalable plasma synthesis technology, the catalysts have potential for application in the CO 2 conversion industry. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Premaximum observations of the type Ia SN 1990N

International Nuclear Information System (INIS)

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

1991-01-01

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

Narrow-gap physical vapour deposition synthesis of ultrathin SnS1-xSex (0 ≤ x ≤ 1) two-dimensional alloys with unique polarized Raman spectra and high (opto)electronic properties.

Science.gov (United States)

Gao, Wei; Li, Yongtao; Guo, Jianhua; Ni, Muxun; Liao, Ming; Mo, Haojie; Li, Jingbo

2018-05-10

Here we report ultrathin SnS1-xSex alloyed nanosheets synthesized via a narrow-gap physical vapour deposition approach. The SnS1-xSex alloy presents a uniform quadrangle shape with a lateral size of 5-80 μm and a thickness of several nanometers. Clear orthorhombic symmetries and unique in-plane anisotropic properties of the 2D alloyed nanosheets were found with the help of X-ray diffraction, high resolution transmission electron microscopy and polarized Raman spectroscopy. Moreover, 2D alloyed field-effect transistors were fabricated, exhibiting a unipolar p-type semiconductor behavior. This study also provided a lesson that the thickness of the alloyed channels played the major role in the current on/off ratio, and the high ratio of 2.10 × 102 measured from a large ultrathin SnS1-xSex device was two orders of magnitude larger than that of previously reported SnS, SnSe nanosheet based transistors because of the capacitance shielding effect. Obviously enhanced Raman peaks were also found in the thinner nanosheets. Furthermore, the ultrathin SnS0.5Se0.5 based photodetector showed a highest responsivity of 1.69 A W-1 and a short response time of 40 ms under illumination of a 532 nm laser from 405 to 808 nm. Simultaneously, the corresponding highest external quantum efficiency of 392% and detectivity of 3.96 × 104 Jones were also achieved. Hopefully, the narrow-gap synthesis technique provides us with an improved strategy to obtain large ultrathin 2D nanosheets which may tend to grow into thicker ones for stronger interlayer van der Waals forces, and the enhanced physical and (opto)electrical performances in the obtained ultrathin SnS1-xSex alloyed nanosheets prove their great potential in the future applications for versatile devices.

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

International Nuclear Information System (INIS)

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

1990-01-01

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

Single-Crystal Growth of Cl-Doped n-Type SnS Using SnCl2 Self-Flux.

Science.gov (United States)

Iguchi, Yuki; Inoue, Kazutoshi; Sugiyama, Taiki; Yanagi, Hiroshi

2018-06-05

SnS is a promising photovoltaic semiconductor owing to its suitable band gap energy and high optical absorption coefficient for highly efficient thin film solar cells. The most significant carnage is demonstration of n-type SnS. In this study, Cl-doped n-type single crystals were grown using SnCl 2 self-flux method. The obtained crystal was lamellar, with length and width of a few millimeters and thickness ranging between 28 and 39 μm. X-ray diffraction measurements revealed the single crystals had an orthorhombic unit cell. Since the ionic radii of S 2- and Cl - are similar, Cl doping did not result in substantial change in lattice parameter. All the elements were homogeneously distributed on a cleaved surface; the Sn/(S + Cl) ratio was 1.00. The crystal was an n-type degenerate semiconductor with a carrier concentration of ∼3 × 10 17 cm -3 . Hall mobility at 300 K was 252 cm 2 V -1 s -1 and reached 363 cm 2 V -1 s -1 at 142 K.

Fabrication of novel SnO2 nanofibers bundle and their optical properties

International Nuclear Information System (INIS)

Butt, Faheem K.; Cao, Chuanbao; Khan, Waheed S.; Ali, Zulfiqar; Mahmood, Tariq; Ahmed, R.; Hussain, Sajad; Nabi, Ghulam

2012-01-01

Here we report on the synthesis of novel SnO 2 nanofibers bundle (NFB) by using ball milled Fe powders via chemical vapor deposition (CVD). The reaction was carried out in a horizontal tube furnace (HTF) at 1100 °C under Ar flow. The as prepared product was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction (SAED). The microscopy analysis reveals the existence of tubular structure that might be formed by the accumulation of nanofibers. The Raman spectrum reveals that the product is rutile SnO 2 with additional peaks ascribed to defects or oxygen vacancies. Room temperature Photoluminescence (PL) spectrum exhibits three emission bands at 369, 450 and 466.6 nm. Using optical absorbance data, a direct optical bandgap of 3.68 eV was calculated. -- Graphical abstract: Novel SnO 2 nanofibers bundle (NFB) fabricated via CVD method. Field emission scanning electron microscopy image of novel SnO 2 NFB and their room temperature PL emission. Highlights: ► Synthesis of novel SnO 2 nanofibers bundle at 1100 °C under partial flow of Ar gas. ► A VLS mechanism is proposed for the formation of SnO 2 nanofibers. ► The PL spectrum exhibits three emission bands at 369, 450 and 466.6 nm. ► A direct optical bandgap of 3.68 eV was calculated.

Phase diagram of the ternary Zr-Ti-Sn system

International Nuclear Information System (INIS)

Arias, D.; Gonzalez Camus, M.

1987-01-01

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

Structural properties and hyperfine characterization of Sn-substituted goethites

Energy Technology Data Exchange (ETDEWEB)

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

2012-04-16

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

Tin - an unlikely ally for silicon field effect transistors?

KAUST Repository

Hussain, Aftab M.

2014-01-13

We explore the effectiveness of tin (Sn), by alloying it with silicon, to use SiSn as a channel material to extend the performance of silicon based complementary metal oxide semiconductors. Our density functional theory based simulation shows that incorporation of tin reduces the band gap of Si(Sn). We fabricated our device with SiSn channel material using a low cost and scalable thermal diffusion process of tin into silicon. Our high-κ/metal gate based multi-gate-field-effect-transistors using SiSn as channel material show performance enhancement, which is in accordance with the theoretical analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic and transport behaviour in Pr3X(X=In,Sn,Ga,Ge,Ni,Co,Ru,Ir) systems

International Nuclear Information System (INIS)

Garde, C.S.; Ray, J.

1998-01-01

Magnetic and transport studies on Pr 3 X (X=In, Sn, Ga, Ge, Ni, Co, Ru, Ir) systems gave evidence for complex magnetic behaviour. All the systems, except X=Sn, exhibit ferromagnetic ordering. The X=Sn system exhibits antiferromagnetic ordering. For X=Ga and Sn, metamagnetic behaviour has been observed. Crystal field effects are found to play an important role in influencing magnetic behaviour. The strength of the crystal field term has also been estimated. (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

High quality NMP exfoliated graphene nanosheet-SnO2 composite anode material for lithium ion battery.

Science.gov (United States)

Ravikumar, Raman; Gopukumar, Sukumaran

2013-03-21

A graphene nanosheet-SnO(2) (GNS-SnO(2)) composite is prepared using N-methylpyrrolidone as a solvent to exfoliate graphene from graphite bar with the aid of CTAB by single phase co-precipitation method. The synthesized composites has been characterised physically by powder XRD which confirms the formation of the composite tetragonal SnO(2) crystal system with the low intense broad 002 plane for GNS. The sandwiched morphology of GNS-SnO(2) and the formation of nanosized particles (around 20 nm) have been confirmed by SEM and TEM images. The presence of sp(2) carbon in the GNS is clear by the highly intense G than D band in laser Raman spectroscopy analysis; furthermore, a single chemical shift has been observed at 132.14 ppm from solid-state (13)C NMR analysis. The synthesized composite has been electrochemically characterized using charge-discharge and EIS analysis. The capacity retentions at the end of the first 10 cycles is 57% (100 mA g(-1) rate), the second 10 cycles is 77.83% (200 mA g(-1)), and the final 10 cycles (300 mA g(-1)) is 81.5%. Moreover the impedance analysis clearly explains the low resistance pathway for Li(+) insertion after 30 cycles when compared with the initial cycle. This superior characteristic of GNS-SnO(2) composite suggests that it is a promising candidate for lithium ion battery anode.

S-N Curves of high resistance steels in the gigacyclic regime; Curvas S-N de aceros de alta resistencia dentro del regimen gigaciclico

Energy Technology Data Exchange (ETDEWEB)

Marinez G, I [Conservatoire National des Arts et Metiers-Institut des Technologies et des Materiaux Avances (CNAM-ITMA), Paris (France); Dominguez A, G [Instituto Tecnologico de Celaya, Guanajuato (Mexico); Bathias, C [Conservatoire National des Arts et Metiers-Institut des Technologies et des Materiaux Avances (CNAM-ITMA), Paris (France)

2004-04-15

In this paper, the fatigue behavior of high strength steel used for mechanical parts has been investigated in the gigacycle fatigue regime. An experimental study has been carried out with both: R = 0.1 (perlitic-ferritic steel) and R = -1 (perlitic-ferritic steel, bainitic steel, martensitic steels) loads, at a high frequency of 20 khz up to 1010 cycles, to determine the S-N curves when fatigue life is more than 107 cycles. Comparison of experimental results at frequencies of 20 khz and 30 Hz with R = -1, shows that the S-N curve has a good agreement between 105 and 107 cycles for the high strength steels, Furthermore, fracture surface observations are made by SEM; the transition of crack initiation site is described. The generalization of gigacycle fatigue behavior is analyzed. More often initiation of fatigue crack at 109 cycles is a bulk phenomenon with an important effect of stress concentration due to mineral inclusions or perlitic platelets. Thus, the Murakami model is efficient when we can measure the defects associated with fracture, but it can not take into account the microstructure effect related to platelets phenomenon. [Spanish] En este trabajo se investigo el comportamiento en fatiga gigaciclica de varios aceros de alta resistencia utilizados en la industria automotriz. El estudio experimental se llevo a cabo utilizando dos diferentes valores de carga: R = 0.1 (acero perlitoferritico) y R = -1 (acero perlito-ferritico, acero bainitico, aceros martensiticos), a una frecuencia de ensayo de 20 kHz y hasta 1010 ciclos, para determinar las curvas S-N arriba de 107 ciclos. La comparacion de resultados experimentales obtenidos utilizando frecuencias de ensayo de 20 kHz y 30 Hz con la relacion de carga R = - 1, muestran la continuidad de las curvas S-N entre 105 y 107 ciclos para estos aceros de alta resistencia. Por otro lado, observaciones de la superficie de fractura se efectuaron utilizando el microscopio electronico de barrido; se describe la transicion

The effect of doping on thermoelectric performance of p-type SnSe: Promising thermoelectric material

Energy Technology Data Exchange (ETDEWEB)

Singh, Niraj Kumar; Bathula, Sivaiah; Gahtori, Bhasker [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Tyagi, Kriti [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Acdemy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (NPL) Campus, New Delhi (India); Haranath, D. [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

2016-05-25

Tin selenide (SnSe) based thermoelectric materials are being explored for making inexpensive and efficient thermoelectric devices with improved thermoelectric efficiency. As both Sn and Se are earth abundant and relatively inexpensive and these alloys do not involve toxic materials, such as lead and expensive tellurium. Hence, in the present study, we have synthesized SnSe doped with 2 at% of aluminium (Al), lead (Pb), indium (In) and copper (Cu) individually, which is not reported in literature. Out of these, Cu doped SnSe resulted in enhancement of figure-of-merit (zT) of ∼0.7 ± 0.02 at 773 K, synthesized employing conventional fusion method followed by spark plasma sintering. This enhancement in zT is ∼16% over the existing state-of-the-art value for p-type SnSe alloy doped with expensive Ag. This enhancement in ZT is primarily due to the presence of Cu{sub 2}Se second phase associated with intrinsic nanostructure formation of SnSe. This enhancement has been corroborated with the microstructural characterization using field emission scanning electron microscopy and X-ray diffraction studies. Also, Cu doped SnSe exhibited a higher value of carrier concentration in comparison to other samples doped with Al, Pb and In. Further, the compatibility factor of Cu doped SnSe alloys exhibited value of 1.62 V{sup −1} at 773 K and it is suitable to segment with most of the novel TE materials for obtaining the higher thermoelectric efficiencies. - Highlights: • Tin selenide (SnSe) doped with non-toxic and inexpensive dopants. • Synthesized highly dense SnSe employing Spark plasma sintering. • Enhanced thermoelectric compatibility factor of SnSe. • Enhanced thermoelectric performance of SnSe doped with Copper.

Anisotropy of critical current density in the superconducting Nb/sub 3/Sn tape wires

Energy Technology Data Exchange (ETDEWEB)

Glowacki, B A [Technical Univ., Wroclaw (Poland). Inst. of Fundamental Electrotechnics and Electrotechnology

1985-04-01

In this letter the results are presented of an investigation of Isub(c parallel) and Isub(c perpendicular) in Nb/sub 3/Sn layers obtained in the process diffusion of tin atoms from liquid bronze solution Cu-80% Sn to the Nb-1.5% Zr substrate. Measurements of critical current density in Nb/sub 3/Sn layers were carried out in a perpendicular magnetic field of the induction value 4.25 T for different sample surface orientations in relation to the magnetic field strength vector defined by the value of angle. The critical current density was measured at a temperature of 4.2 K. Phase identification and investigation of the microstructure of superconducting Nb-Sn layers were performed on the Moessbauer spectrometer and scanning electron microscope, respectively. Classification measurements of grains in Nb-Sn layers were carried out with TV automatic image analyser. The texture and lattice parameter in Nb/sub 3/Sn layers were investigated by means of an X-ray diffractometer. The surface zone of Nb/sub 3/Sn layer was removed with the use of an argon ion gun. Results are presented and discussed.

SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU

International Nuclear Information System (INIS)

Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P.; Cenko, S. B.; Filippenko, A. V.; Silverman, J. M.; Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N.; Jha, S. W.; McCully, C.; Anderson, J. P.; De Jaeger, T.; Forster, F.; Benetti, S.; Bufano, F.

2013-01-01

We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II λ6355 line that can be cleanly decoupled from the lower velocity ''photospheric'' component. This Si II λ6355 HVF fades by phase –5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of ∼12,000 km s –1 until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v ≈ 12,000 km s –1 with narrow line width and long velocity plateau, as well as an HVF beginning at v ≈ 31,000 km s –1 two weeks before maximum. SN 2012fr resides on the border between the ''shallow silicon'' and ''core-normal'' subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the ''low velocity gradient'' group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

Superior cycle performance and high reversible capacity of SnO2/graphene composite as an anode material for lithium-ion batteries

OpenAIRE

Liu, Lilai; An, Maozhong; Yang, Peixia; Zhang, Jinqiu

2015-01-01

SnO2/graphene composite with superior cycle performance and high reversible capacity was prepared by a one-step microwave-hydrothermal method using a microwave reaction system. The SnO2/graphene composite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscopy and high resolution transmission electron microscopy. The size of ...

Fourier Transfrom Ion Cyclotron Resonance Mass Spectrometry at High Magnetic Field

Science.gov (United States)

Marshall, Alan G.

1998-03-01

At high magnetic field (9.4 tesla at NHMFL), Fourier transform ion cyclotron resonance mass spectrometry performance improves dramatically: mass resolving power, axialization efficiency, and scan speed (each proportional to B), maximum ion mass, dynamic range, ion trapping period, kinetic energy, and electron self-cooling rate for sympathetic cooling (each proportional to B^2), and ion coalescence tendency (proportional 1/B^2). These advantages may apply singly (e.g., unit mass resolution for proteins of >100,000 Da), or compound (e.g., 10-fold improvement in S/N ratio for 9.4 T vs. 6 T at the same resolving power). Examples range from direct determination of molecular formulas of diesel fuel components by accurate mass measurement (=B10.1 ppm) to protein structure and dynamics probed by H/D exchange. This work was supported by N.S.F. (CHE-93-22824; CHE-94-13008), N.I.H. (GM-31683), Florida State University, and the National High Magnetic Field Laboratory in Tallahassee, FL.

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.))

Semiconducting ZnSnN{sub 2} thin films for Si/ZnSnN{sub 2} p-n junctions

Energy Technology Data Exchange (ETDEWEB)

Qin, Ruifeng [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China); Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Cao, Hongtao; Liang, Lingyan, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn; Xie, Yufang; Zhuge, Fei; Zhang, Hongliang; Gao, Junhua; Javaid, Kashif [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Liu, Caichi; Sun, Weizhong, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China)

2016-04-04

ZnSnN{sub 2} is regarded as a promising photovoltaic absorber candidate due to earth-abundance, non-toxicity, and high absorption coefficient. However, it is still a great challenge to synthesize ZnSnN{sub 2} films with a low electron concentration, in order to promote the applications of ZnSnN{sub 2} as the core active layer in optoelectronic devices. In this work, polycrystalline and high resistance ZnSnN{sub 2} films were fabricated by magnetron sputtering technique, then semiconducting films were achieved after post-annealing, and finally Si/ZnSnN{sub 2} p-n junctions were constructed. The electron concentration and Hall mobility were enhanced from 2.77 × 10{sup 17} to 6.78 × 10{sup 17 }cm{sup −3} and from 0.37 to 2.07 cm{sup 2} V{sup −1} s{sup −1}, corresponding to the annealing temperature from 200 to 350 °C. After annealing at 300 °C, the p-n junction exhibited the optimum rectifying characteristics, with a forward-to-reverse ratio over 10{sup 3}. The achievement of this ZnSnN{sub 2}-based p-n junction makes an opening step forward to realize the practical application of the ZnSnN{sub 2} material. In addition, the nonideal behaviors of the p-n junctions under both positive and negative voltages are discussed, in hope of suggesting some ideas to further improve the rectifying characteristics.

Individual SnO2 nanowire transistors fabricated by the gold microwire mask method

International Nuclear Information System (INIS)

Sun Jia; Tang Qingxin; Lu Aixia; Jiang Xuejiao; Wan Qing

2009-01-01

A gold microwire mask method is developed for the fabrication of transistors based on single lightly Sb-doped SnO 2 nanowires. Damage of the nanowire's surface can be avoided without any thermal annealing and surface modification, which is very convenient for the fundamental electrical and photoelectric characterization of one-dimensional inorganic nanomaterials. Transport measurements of the individual SnO 2 nanowire devices demonstrate the high-performance n-type field effect transistor characteristics without significant hysteresis in the transfer curves. The current on/off ratio and the subthreshold swing of the nanowire transistors are found to be 10 6 and 240 mV/decade, respectively.

A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

International Nuclear Information System (INIS)

Chen, Z; Kametani, F; Larbalestier, D C; Chen, Y; Xie, Y; Selvamanickam, V

2009-01-01

We have made extensive low temperature and high field evaluations of a recent 2.1 μm thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm) 2 O 3 nanoprecipitates, which are self-aligned in planes tilted ∼7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J c values of ∼3.1 MA cm -2 at 77 K and ∼43 MA cm -2 at 4.2 K, and by a strongly enhanced irreversibility field H irr , which reaches that of Nb 3 Sn (∼28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J c values are ∼15% of the depairing current density J d , much the highest of any superconductor suitable for magnet construction.

A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

Energy Technology Data Exchange (ETDEWEB)

Chen, Z; Kametani, F; Larbalestier, D C [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Chen, Y; Xie, Y; Selvamanickam, V [SuperPower Incorporated, Schenectady, NY 12304 (United States)], E-mail: zhijun@asc.magnet.fsu.edu

2009-05-15

We have made extensive low temperature and high field evaluations of a recent 2.1 {mu}m thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm){sub 2}O{sub 3} nanoprecipitates, which are self-aligned in planes tilted {approx}7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J{sub c} values of {approx}3.1 MA cm{sup -2} at 77 K and {approx}43 MA cm{sup -2} at 4.2 K, and by a strongly enhanced irreversibility field H{sub irr}, which reaches that of Nb{sub 3}Sn ({approx}28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J{sub c} values are {approx}15% of the depairing current density J{sub d}, much the highest of any superconductor suitable for magnet construction.

Quantum oscillation evidence for a topological semimetal phase in ZrSnTe

Science.gov (United States)

Hu, Jin; Zhu, Yanglin; Gui, Xin; Graf, David; Tang, Zhijie; Xie, Weiwei; Mao, Zhiqiang

2018-04-01

The layered WHM-type (W =Zr /Hf /La , H =Si /Ge /Sn /Sb , M =S /Se /Te ) materials represent a large family of topological semimetals, which provides an excellent platform to study the evolution of topological semimetal state with the fine tuning of spin-orbit coupling and structural dimensionality for various combinations of W , H , and M elements. In this work, through high field de Haas-van Alphen (dHvA) quantum oscillation studies, we have found evidence for the predicted topological nontrivial bands in ZrSnTe. Furthermore, from the angular dependence of quantum oscillation frequency, we have revealed the three-dimensional Fermi surface topologies of this layered material owing to strong interlayer coupling.

ASYMMETRY IN THE OUTBURST OF SN 1987A DETECTED USING LIGHT ECHO SPECTROSCOPY

International Nuclear Information System (INIS)

Sinnott, B.; Welch, D. L.; Sutherland, P. G.; Rest, A.; Bergmann, M.

2013-01-01

We report direct evidence for asymmetry in the early phases of SN 1987A via optical spectroscopy of five fields of its light echo system. The light echoes allow the first few hundred days of the explosion to be reobserved, with different position angles providing different viewing angles to the supernova. Light echo spectroscopy therefore allows a direct spectroscopic comparison of light originating from different regions of the photosphere during the early phases of SN 1987A. Gemini multi-object spectroscopy of the light echo fields shows fine structure in the Hα line as a smooth function of position angle on the near-circular light echo rings. Hα profiles originating from the northern hemisphere of SN 1987A show an excess in redshifted emission and a blue knee, while southern hemisphere profiles show an excess of blueshifted Hα emission and a red knee. This fine structure is reminiscent of the 'Bochum event' originally observed for SN 1987A, but in an exaggerated form. Maximum deviation from symmetry in the Hα line is observed at position angles 16° and 186°, consistent with the major axis of the expanding elongated ejecta. The asymmetry signature observed in the Hα line smoothly diminishes as a function of viewing angle away from the poles of the elongated ejecta. We propose an asymmetric two-sided distribution of 56 Ni most dominant in the southern far quadrant of SN 1987A as the most probable explanation of the observed light echo spectra. This is evidence that the asymmetry of high-velocity 56 Ni in the first few hundred days after explosion is correlated to the geometry of the ejecta some 25 years later.

Field emission characteristics of SnO2/CNT composite prepared by microwave assisted wet impregnation

CSIR Research Space (South Africa)

Kesavan Pillai, Sreejarani

2012-01-01

Full Text Available SnO2/CNT composites were prepared by microwave assisted wet impregnation at 60 °C. The process was optimized by varying the microwave power and reaction time. Raman analysis showed the typical features of the rutile phase of as-synthesized SnO2...

Three NiAs-Ni 2In Type Structures in the Mn-Sn System

Science.gov (United States)

Elding-Pontén, Margareta; Stenberg, Lars; Larsson, Ann-Kristin; Lidin, Sven; Ståhl, Kenny

1997-03-01

TheB8-type structure field of the Mn-Sn system has been investigated. Two high temperature phases (HTP1 and HTP2) and one low temperature phase (Mn3Sn2) were found. They all crystallize with the NiAs structure type with part of the trigonal bipyramidal interstices filled by manganese atoms in an ordered manner. The ordering as well as the manganese content is different for the three phases, giving rise to three different orthorhombic superstructures. Mn3Sn2seems to have the lowest manganese content, since the corresponding basal unit cell is smaller than for HTP1-2. Structural models of the phases are based on selected area electron diffraction, X-ray powder diffraction, and preliminary single crystal X-ray measurements. The ideal cell parameters found are (a=7ahex,b=3ahex,c=chex), (a=5ahex,b=3ahex,c=chex), and (a=2ahex,b=3ahex,c=chex) for HTP1, HTP2, and Mn3Sn2, respectively. The crystal structure of Mn3Sn2has been refined by means of the Rietveld method from X-ray powder diffraction data. Mn3Sn2is orthorhombic,Pnma,a=7.5547(2),b=5.4994(2),c=8.5842(2) Å,Z=4. (Pbnmin the setting above.) The compound is isostructural with Ni3Sn2andγ‧-Co3Sn2(H. Fjellvåg and A. Kjekshus,Acta Chem. Scand.A40, 23-30 (1986)). FinalRp=8.97%,Rwp=11.44%, GOF=2.86, andRBragg=4.11% using 43 parameters and 5701 observations and 330 Bragg reflections.

Microminiature Hall probes based on n-InSb(Sn)/i-GaAs heterostructure for pulsed magnetic field applications up to 52 T

Energy Technology Data Exchange (ETDEWEB)

Mironov, O.A.; Myronov, M.; Durov, S.; Drachenko, O.; Leotin, J

2004-04-30

Microminiature Hall probes with sensitive area down to 33x115 {mu}m and based on n-InSb/i-GaAs optimized Sn-doped MBE-grown heterostructures are reported. The 'metallurgical' thicknesses of the n-InSb epilayers lie in the range d{sup m}=1.1-10.5 {mu}m giving room-temperature mobilities of (9-15)x10{sup 3} cm{sup 2}/Vs with carrier densities of (0.96-2.56)x10{sup 18} cm{sup -3}. Characterization of the devices was performed by magnetotransport measurements in quasi-static and pulsed magnetic fields. In the temperature range 1.1-300 K and in magnetic fields up to 12 T (static) and up to 52 T (pulsed, {tau}=120 mS), transport measurements yield remarkable linearity of the Hall voltage up to 52 T and sensitivity, as well as demonstrating the high-temperature stability of the Hall voltage, the offset voltage and the device resistivity. No significant effect of the high current up to 150 mA on either the sensitivity or the resistivity is observed.

Analysis of heat capacity and Mössbauer data for LuZnSn2 compound

Directory of Open Access Journals (Sweden)

Łątka Kazimierz

2015-03-01

Full Text Available New analysis of heat capacity data is presented for LuZnSn2 compound that takes into account anharmonic effects together with the existence of Einstein modes. 119mSn Mössbauer spectroscopy was used to monitor the hyperfine parameters at the two crystallographically inequivalent Sn sites in the studied compound. The problem of non-unique mathematical resonance spectrum description and the problem how to choose physically meaningful set of hyperfine parameters will be thoroughly discussed. Measured quadrupole interaction constants by 119mSn Mössbauer spectroscopy give estimations for Vzz component of electric field gradient tensor at both Sn sites in LuZnSn2.

Synchrotron radiation techniques for the characterization of Nb$_{3}$Sn superconductors

CERN Document Server

Scheuerlein, C; Buta, F

2009-01-01

The high flux of high energy x-rays that can be provided through state-of-the-art high energy synchrotron beam lines has enabled a variety of new experiments with the highly absorbing Nb$_{3}$Sn superconductors. We report different experiments with Nb$_{3}$Sn strands that have been conducted at the ID15 High Energy Scattering beam line of the European Synchrotron Radiation Facility (ESRF). Synchrotron x-ray diffraction has been used in order to monitor phase transformations during in-situ reaction heat treatments prior to Nb$_{3}$Sn formation, and to monitor Nb$_{3}$Sn growth. Fast synchrotron micro-tomography was applied to study void growth during the reaction heat treatment of Internal Tin strands. The elastic strain in the different phases of fully reacted Nb$_{3}$Sn composite conductors can be measured by high resolution x-ray diffraction during in-situ tensile tests.