Reduction of [Cp*Sb]4 with Subvalent Main-Group Metal Reductants: Syntheses and Structures of [(L1 Mg)4 (Sb4 )] and [(L2 Ga)2 (Sb4 )] Containing Edge-Missing Sb4 Units.

PubMed

Ganesamoorthy, Chelladurai; Krüger, Julia; Wölper, Christoph; Nizovtsev, Anton S; Schulz, Stephan

2017-02-16

[Cp*Sb] 4 (Cp*=C 5 Me 5 ) reacts with [L 1 Mg] 2 and L 2 Ga with formation of [(L 1 Mg) 4 (μ 4 ,η 1:2:2:2 -Sb 4 )] (L 1 =iPr 2 NC[N(2,6-iPr 2 C 6 H 3 )] 2 , 1) and [(L 2 Ga) 2 (μ,η 2:2 -Sb 4 )] (L 2 =HC[C(Me)N(2,6-iPr 2 C 6 H 3 )] 2 , 2). The cleavage of the Sb-Sb and Sb-C bonds in [Cp*Sb] 4 are the crucial steps in both reactions. The formation of 1 occurred by elimination of the Cp* anion and formation of Cp*MgL 1 , while 2 was formed by reductive elimination of Cp* 2 and oxidative addition of L 2 Ga to the Sb 4 unit. 1 and 2 were characterized by heteronuclear NMR spectroscopy and single-crystal X-ray diffraction, and their bonding situation was studied by quantum chemical calculations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-diffusion in 69Ga121Sb/71Ga123Sb isotope heterostructures

NASA Astrophysics Data System (ADS)

Bracht, H.; Nicols, S. P.; Haller, E. E.; Silveira, J. P.; Briones, F.

2001-05-01

Gallium and antimony self-diffusion experiments have been performed in undoped 69Ga121Sb/71Ga123Sb isotope heterostructures at temperatures between 571 and 708 °C under Sb- and Ga-rich ambients. Ga and Sb profiles measured with secondary ion mass spectrometry reveal that Ga diffuses faster than Sb by several orders of magnitude. This strongly suggests that the two self-atom species diffuse independently on their own sublattices. Experimental results lead us to conclude that Ga and Sb diffusion are mediated by Ga vacancies and Sb interstitials, respectively, and not by the formation of a triple defect proposed earlier by Weiler and Mehrer [Philos. Mag. A 49, 309 (1984)]. The extremely slow diffusion of Sb up to the melting temperature of GaSb is proposed to be a consequence of amphoteric transformations between native point defects which suppress the formation of those native defects which control Sb diffusion. Preliminary experiments exploring the effect of Zn indiffusion at 550 °C on Ga and Sb diffusion reveal an enhanced intermixing of the Ga isotope layers compared to undoped GaSb. However, under the same conditions the diffusion of Sb was not significantly affected.

Growth and characterization of an InSb infrared photoconductor on Si via an AlSb/GaSb buffer

NASA Astrophysics Data System (ADS)

Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt

2018-05-01

A 99.6% relaxed InSb layer is grown on a 6° offcut (1 0 0) Si substrate via an AlSb/GaSb buffer using molecular beam epitaxy (MBE). A 200 nm GaSb buffer is first grown on Si and the lattice mismatch between them is accommodated by an interfacial misfit (IMF) array consisting of uniformly distributed 90° misfit dislocations. Si delta doping is introduced during the growth of GaSb to reduce the density of threading dislocation. Subsequently, a 50 nm AlSb buffer is grown followed by a 0.8 μm InSb layer. The InSb layer exhibits a 300 K electron mobility of 22,300 cm2/Vs. An InSb photoconductor on Si is demonstrated with a photoconductive gain from 77 K to 200 K under a 700 °C maintained blackbody.

40 CFR 721.3025 - Fatty acids C12-18, C18 unsaturated, C12-18 alkyl esters (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acids C12-18, C18 unsaturated... Significant New Uses for Specific Chemical Substances § 721.3025 Fatty acids C12-18, C18 unsaturated, C12-18... chemical substance identified generically as fatty acids C12-18, C18 unsaturated, C12-18 alkyl esters (PMNs...

AsSb energetics in argentian sulfosalts

NASA Astrophysics Data System (ADS)

Ghosal, Subhabrata; Sack, Richard O.

1995-09-01

Experimental brackets on As-Sb partitioning between polybasite-pearceite {Pbp; (Cu, Ag) 16(Sb, As) 2S 11} and pyrargyrite-proustite {Ppr; (Cu, Ag) 3(Sb, As)S 3}, and between pyrargyrite-proustite, and miargyrite and smithite {αMi, βMi, Smt; Ag(Sb, As)S 2} (350-400°C; evacuated silica tubes) define standard state Gibbs energies of theAsSb exchange reactions {Ag 16As 2S 11+Ag 3SbS 3=Ag 16Sb 2S 11 + Ag 3AsS 3, Δ Gro Pbp-Ppr = 0.65 ± 0.60 kJ/gfw; Ag 3AsS 3, + AgSbS 2 = Ag 3SbS 3 + AgASS 2, Δ overlineGro Ppr-α Mi = 3.10 ± 0.50 kJ/gfw, Δ Gro PPr-Smt = 1.70 ± 0.50 kJ/gfw and the nonidealities associated with the AsSb substitutions in these minerals (measured by symmetric regular-solution parameters for formula units on a one AsSb site basis; WAsSbPbp = 4.00 ± 0.25 kJ/gfw; WAsSbPpr =6.00 ± 0 .60 kJ/gfw; WAsSbαMi = WAsSbSmt = 7.00 ± 0.50 kJ/gfw). The above constraints applied to the miscibility gap between Ag (Sb, As) S 2 solutions with α-miargyrite and smithite structures at 350°C determine the relative stabilities of these structures in the As and Sb endmembers to be: ( GSbo, α Mi - GSbo, Smt) ˜ -0.63 kJ/gfw; ( GAso, α Mi - GAsSmt) ˜ 0.77 kJ/gfw. Combining these constraints with the calorimetric data of Bryndzia and Kleppa (1988, 1989) and our melting point determinations we have constructed a phase diagram for the AgSbS 2AgAsS 2 subsystem. The salient features of this diagram are (1) eutectic behaviour ( T ˜ 396°C, XAs ˜ 0.50), (2) modest increase in the temperature of the α → β miargyrite transition with As substitution (˜380°C in Sb-subsystem; 386.6°C at XAsMi ˜ 0.36), (3) a 42.5°C depression of the trechmannite-smithite transition with preferential incorporation of Sb in smithite { smithite ( XAs ˜ 0.62) → α-miargyrite ( XAs ˜ 0.34) + trechmannite (X As ˜ 1.00) at ˜277.5°C}, and (4) widening of the miargyrite-trechmannite gap at lower temperatures. The latter feature is consistent with the inference that the most As

121Sb and 35Cl NQR in RCN · SbCl5 Complexes

NASA Astrophysics Data System (ADS)

Semin, G. K.; Kuznetsov, S. I.; Raevsky, A. M.; Bryukhova, E. V.

1994-05-01

35Cl and 121Sb NQR spectra of RCN · SbCl5 complexes with R = Et, n-Pr, i-Pr, n-Bu, n-C5H11 , Cl(CH2)2, C6H4CH2, Ph, Cl, Me, CCl3 were measured and /or refined at 77 K. Redistribution of the "transferred charge" in the SbCl5 fragment of the complexes under study was investigated. The existence of a specific region of dispersion of the electron-nuclear motions (DENM) in RCN · SbCl5 complexes was established.

[Study on the analytical methods of catechins in tea and green tea polyphenol samples by high performance liquid chromatography].

PubMed

Dai, J; Wang, H X; Chen, S W; Tang, J

2001-09-01

Hypersil BDS C18 and Zorbax SB C18, suitable to separate simultaneously seven kinds of catechins and caffeine, were screened out from seven brands of reversed-phase columns. Mobile phase was a solution of methanol-water-acetic acid (or trifluoro acetic acid). Seven kinds of catechins in tea samples from six places in China and three green tea polyphenol(GTP) samples from different producers were separated and determined in 30 min by isocratic and gradient elutions. The effects of mobile phase components and temperature of column on retention parameters of catechins and caffeine are reviewed. Chromatographic conditions and pretreatment methods of samples were optimized. Gallocatechin gallate(GCG) and (-)-catechin gallate(CG) were identified by electrospray ionization mass spectrometry(ESI-MS) and prepared by high performance liquid chromatography for quantitative analysis. The other catechins, (-)-epigallocatechin (EGC), (+)-catechin (D-C), (-)-epicatechin(EC), (-)-epigallocatechin gallate(EGCG), (-)-epicatechin gallate(ECG) were identified with standards.

Carrier Concentration Control of GaSb/GaInAsSb System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazzari, J.-L.; Anda, F. de; Nieto, J.

2007-02-22

The residual carrier concentration of GaSb and GaSb-lattice matched Ga1-xInxAsySb1-y alloys (x = 0.12-0.26; y = 0.9x) grown by liquid phase epitaxy (LPE) and molecular beam epitaxy (MBE) was studied as a function of growth temperature, V/III ratio and alloy composition. Typical carrier concentrations p {approx} 2-3x1016 cm-3 were obtained for undoped GaSb grown by MBE at 480 deg. C, by LPE from Ga-rich melt at low temperature (400 deg. C), and by LPE from Sb-rich melts at {approx}600 deg. C. The native acceptor defect responsible of the high p-type residual doping in GaSb is reduced when the indium concentrationmore » is increased, and disappears for indium rich alloys (x = 0.23, 0.26). Tellurium compensation was used for controlled n-type doping in the (0.05-30)x1017 cm-3 range. A maximum of free carrier concentration was 1.5x1018 cm-3 for LPE layers, 2x1018 cm-3 for MBE layers grown at 1.0 {mu}m/h, 3.5x1018 cm-3 for MBE layers grown at 0.2 {mu}m/h. SIMS measurements showed Te concentrations of more than 1020 at/cm3, suggesting the formation of ternary GaSb1-xTex solid solution.« less

Study on electrical properties of metal/GaSb junctions using metal-GaSb alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishi, Koichi, E-mail: nishi@mosfet.t.u-tokyo.ac.jp; Yokoyama, Masafumi; Kim, Sanghyeon

2014-01-21

We study the metal-GaSb alloy formation, the structural properties and the electrical characteristics of the metal-alloy/GaSb diodes by employing metal materials such as Ni, Pd, Co, Ti, Al, and Ta, in order to clarify metals suitable for GaSb p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) as metal-GaSb alloy source/drain (S/D). It is found that Ni, Pd, Co, and Ti can form alloy with GaSb by rapid thermal annealing at 250, 250, 350, and 450 °C, respectively. The Ni-GaSb and Pd-GaSb alloy formation temperature of 250 °C is lower than the conventional dopant activation annealing for ion implantation, which enable us to lower the processmore » temperature. The alloy layers show lower sheet resistance (R{sub Sheet}) than that of p{sup +}-GaSb layer formed by ion implantation and activation annealing. We also study the electrical characteristics of the metal-alloy/GaSb junctions. The alloy/n-GaSb contact has large Schottky barrier height (ϕ{sub B}) for electrons, ∼0.6 eV, and low ϕ{sub B} for holes, ∼0.2 eV, which enable us to realize high on/off ratio in pMOSFETs. We have found that the Ni-GaSb/GaSb Schottky junction shows the best electrical characteristics with ideal factor (n) of 1.1 and on-current/off-current ratio (I{sub on}/I{sub off}) of ∼10{sup 4} among the metal-GaSb alloy/GaSb junctions evaluated in the present study. These electrical properties are also superior to those of a p{sup +}-n diode fabricated by Be ion implantation with activation annealing at 350 °C. As a result, the Ni-GaSb alloy can be regarded as one of the best materials to realize metal S/D in GaSb pMOSFETs.« less

Enhanced superconductivity in SnSb under pressure: a first principles study

NASA Astrophysics Data System (ADS)

Sreenivasa Reddy, P. V.; Kanchana, V.

2017-10-01

First principles electronic structure calculations reveal both SnP and SnSb to be stable in the NaCl structure. In SnSb, a first order phase transition from NaCl to CsCl type structure is observed at around 13 GPa, which is also confirmed from enthalpy calculations and agrees well with experimental and other theoretical reports. Calculations of the phonon spectra, and hence the electron-phonon coupling λep and superconducting transition temperature T c, were performed at zero pressure for both the compounds, and at high pressure for SnSb. These calculations report Tc of 0.614 K and 3.083 K for SnP and SnSb respectively, in the NaCl structure—in good agreement with experiment—whilst at the transition pressure, in the CsCl structure, a drastically increased value of T c around 9.18 K (9.74 K at 20 GPa) is found for SnSb, together with a dramatic increase in the electronic density of states at this pressure. The lowest energy acoustic phonon branches in each structure also demonstrate some softening effects, which are well addressed in this work.

Antiferromagnetism in semiconducting SrMn 2 Sb 2 and BaMn 2 Sb 2 single crystals

DOE PAGES

Sangeetha, N. S.; Smetana, V.; Mudring, A. -V.; ...

2018-01-03

Here, crystals of SrMn 2Sb 2 and BaMn 2Sb 2 were grown using Sn flux and characterized by powder and single-crystal x-ray diffraction, respectively, and by single-crystal electrical resistivity ρ, heat capacity C p, and magnetic susceptibility χ measurements versus temperature T, and magnetization versus field M(H) isotherm measurements. SrMn 2Sb 2 adopts the trigonal CaAl 2Si 2-type structure, whereas BaMn 2Sb 2 crystallizes in the tetragonal ThCr 2Si 2-type structure. The ρ(T) data indicate semiconducting behaviors for both compounds with activation energies of ≳0.35 eV for SrMn 2Sb 2 and 0.16 eV for BaMn 2Sb 2. The χ(T) andmore » C p(T) data reveal antiferromagnetic (AFM) ordering at T N = 110 K for SrMn 2Sb 2 and 450 K for BaMn 2Sb 2. The anisotropic χ(T≤T N) data also show that the ordered moments in SrMn 2Sb 2 are aligned in the hexagonal ab plane, whereas the ordered moments in BaMn 2Sb 2 are aligned collinearly along the tetragonal c axis. The ab-plane M(H) data for SrMn 2Sb 2 exhibit a continuous metamagnetic transition at low fields 02Sb 2 exhibits no metamagnetic transitions up to 5.5 T. The χ(T) and C p(T) data for both SrMn 2Sb 2 and BaMn 2Sb 2 indicate strong dynamic short-range AFM correlations above their respective T N up to at least 900 K within a local-moment picture, corresponding to quasi-two-dimensional magnetic behavior. The present results and a survey of the literature for Mn pnictides with the CaAl 2Si 2 and ThCr 2Si 2 crystal structures show that the T N values for the CaAl 2Si 2-type compounds are much smaller than those for the ThCr 2Si 2-type materials.« less

The Effect of SbI3 Doping on the Structure and Electrical Properties of n-Type Bi1.8Sb0.2Te2.85Se0.15 Alloy Prepared by the Free Growth Method

NASA Astrophysics Data System (ADS)

Wang, Xiaoyu; Yu, Yuan; Zhu, Bin; Gao, Na; Huang, Zhongyue; Xiang, Bo; Zu, Fangqiu

2018-02-01

Thermoelectric technology is regarded as one of the most promising direct power generation techniques via thermoelectric materials. However, the batch production and scale-up application are hindered because of the high-cost and poor performance. In this work, we adopt the free growth method to synthesize a series of the bulk materials of SbI3-doped Bi1.8Sb0.2Te2.85Se0.15 alloys. The structural and component investigations as well as the electrical properties characterization are carried out. The results show that SbI3 promotes the formation of Te-rich regions in the matrix. In addition, the synergistically optimized electrical conductivity and Seebeck coefficient are attained by controlling the SbI3 doping concentration. Thus, the sample with 0.30 wt.% SbI3 displays a highly increased power factor of ˜ 13.57 μW cm-1 K-2, which is nearly 21 times higher than that of the undoped one. Moreover, the free growth method is reproducible, convenient and economical. Therefore, it has great potential as a promising technology for the batch synthesis.

Interfacial characterization and electrical properties of Ni–GaSb contacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Kun-Lin, E-mail: kllin@narlabs.org.tw; Chen, Szu-Hung, E-mail: shchen168@narlabs.org.tw

2014-10-06

The microstructural characterization of Ni–GaSb junctions in samples annealed at 300 °C, 350 °C, and 400 °C in a N{sub 2} atmosphere was elucidated using transmission electron microscopy in conjunction with energy-dispersive spectrometry, nanobeam electron diffraction, and grazing-incident X-ray diffraction. Only the NiSb(Ga) phase is formed at the interface of Ni/GaSb when the annealing temperature is below 350 °C. However, three phases—NiSb, Ni{sub 2}Ga{sub 3}, and NiSb(Ga)—are formed simultaneously at the interface between Ni/GaSb when the annealing temperature is increased to 400 °C, which causes a significant increase in the sheet resistance of the Ni–GaSb alloy. These results indicate that the annealing temperature of themore » Ni/GaSb structure should be maintained below 350 °C for the formation of low-resistance metal Ni/GaSb contacts in GaSb-based p-type metal-oxide-semiconductor field-effect transistors.« less

Fluctuations in [11C]SB207145 PET Binding Associated with Change in Threat-Related Amygdala Reactivity in Humans

PubMed Central

Fisher, Patrick MacDonald; Haahr, Mette Ewers; Jensen, Christian Gaden; Frokjaer, Vibe Gedsoe; Siebner, Hartwig Roman; Knudsen, Gitte Moos

2015-01-01

Serotonin critically affects the neural processing of emotionally salient stimuli, including indices of threat; however, how alterations in serotonin signaling contribute to changes in brain function is not well understood. Recently, we showed in a placebo-controlled study of 32 healthy males that brain serotonin 4 receptor (5-HT4) binding, assessed with [11C]SB207145 PET, was sensitive to a 3-week intervention with the selective serotonin reuptake inhibitor fluoxetine, supporting it as an in vivo model for fluctuations in central serotonin levels. Participants also underwent functional magnetic resonance imaging while performing a gender discrimination task of fearful, angry, and neutral faces. This offered a unique opportunity to evaluate whether individual fluctuations in central serotonin levels, indexed by change in [11C]SB207145 binding, predicted changes in threat-related reactivity (ie, fear and angry vs neutral faces) within a corticolimbic circuit including the amygdala and medial prefrontal and anterior cingulate cortex. We observed a significant association such that decreased brain-wide [11C]SB207145 binding (ie, increased brain serotonin levels) was associated with lower threat-related amygdala reactivity, whereas intervention group status did not predict change in corticolimbic reactivity. This suggests that in the healthy brain, interindividual responses to pharmacologically induced and spontaneously occurring fluctuations in [11C]SB207145 binding, a putative marker of brain serotonin levels, affect amygdala reactivity to threat. Our finding also supports that change in brain [11C]SB207145 binding may be a relevant marker for evaluating neurobiological mechanisms underlying sensitivity to threat and serotonin signaling. PMID:25560201

Hole-dominated transport in InSb nanowires grown on high-quality InSb films

NASA Astrophysics Data System (ADS)

Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U.

2016-12-01

We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between S b 2 S 3 and I n and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40-60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 1017 cm-3 and 1000 cm2 V-1 s-1, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

Dissimilatory Sb(V) reduction by microorganisms isolated from Sb-contaminated sediment

NASA Astrophysics Data System (ADS)

Dovick, M. A.; Kulp, T. R.

2013-12-01

Mining and smelting are major sources of trace metal contamination in freshwater systems. Arsenic (As) is a common contaminant derived from certain mining operations and is a known toxic metalloid and carcinogen. Antimony (Sb) is listed as a pollutant of priority interest by the EPA and is presumed to share similar geochemical and toxicological properties with arsenic. Both elements can occur in four different oxidation states (V, III, 0, and -III) under naturally occurring conditions. In aqueous solutions As(V) and Sb(V) predominate in oxygenated surface waters whereas As(III) and Sb(III) are stable in anoxic settings. Numerous studies have examined microbiological redox pathways that utilize As(V) as a terminal electron acceptor for anaerobic respiration, however there have been few studies on microbial mechanisms that may affect the biogeochemical cycling of Sb in the environment. Here we report bacterial reduction of Sb(V) to Sb(III) in anoxic enrichment cultures and bacterial isolates grown from sediment collected from an Sb contaminated pond at a mine tailings site in Idaho (total pond water Sb concentration = 235.2 +/- 136.3 ug/L). Anaerobic sediment microcosms (40 mL) were established in artificial freshwater mineral salt medium, amended with millimolar concentrations of Sb(V), acetate or lactate, and incubated at 27°C for several days. Antimony(V), lactate, and acetate concentrations were monitored during incubation by High Performance Liquid Chromatography (HPLC) and Ion Chromatography (IC). Live sediment microcosms reduced millimolar amendments of Sb(V) to Sb(III) coupled to the oxidation of acetate and lactate, while no activity occurred in killed controls. Enrichment cultures were established by serially diluting Sb(V)-reducing microcosms in mineral salt medium with Sb(V) and acetate, and a Sb(V)-reducing bacterial strain was isolated by plating on anaerobic agar plates amended with millimolar Sb(V) and acetate. Direct cell counting demonstrated that

Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Luo, Caiqin; Ho, Lok-Ping; Azad, Fahad; Anwand, Wolfgang; Butterling, Maik; Wagner, Andreas; Kuznetsov, Andrej; Zhu, Hai; Su, Shichen; Ling, Francis Chi-Chung

2018-04-01

Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold ˜8 × 1020 cm-3, the as-grown films grown with an appropriate oxygen pressure could be n˜4 × 1020 cm-3. The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the SbZn-2VZn shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. X-ray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples.

First-Principles Study of Structural, Electronic, Optical, and Thermal Properties of BeSiSb2 and MgSiSb2

NASA Astrophysics Data System (ADS)

Benlamari, S.; Boukhtouta, M.; Taïri, L.; Meradji, H.; Amirouche, L.; Ghemid, S.

2018-03-01

Structural, electronic, optical, and thermal properties of ternary II-IV-V2 (BeSiSb2 and MgSiSb2) chalcopyrite semiconductors have been calculated using the full-potential linearized augmented plane wave scheme␣in the generalized gradient approximation. The optimized equilibrium structural parameters ( a, c, and u) are in good agreement with theoretical results obtained using other methods. The band structure and density of states reveal that BeSiSb2 has an indirect (Γ-Z) bandgap of about 0.61 eV, whereas MgSiSb2 has a direct (Γ-Γ) bandgap of 0.80 eV. The dielectric function, refractive index, and extinction coefficient were calculated to investigate the optical properties, revealing that BeSiSb2 and MgSiSb2 present very weak birefringence. The temperature dependence of the volume, bulk modulus, Debye temperature, and heat capacities ( C v and C p) was predicted using the quasiharmonic Debye model at different pressures. Significant differences in properties are observed at high pressure and high temperature. We predict that, at 300 K and 0 GPa, the heat capacity at constant volume C v, heat capacity at constant pressure C P, Debye temperature θ D, and Grüneisen parameter γ will be about 94.91 J/mol K, 98.52 J/mol K, 301.30 K, and 2.11 for BeSiSb2 and about 96.08 J/mol K, 100.47 J/mol K, 261.38 K, and 2.20 for MgSiSb2, respectively.

Quantification of Kryptofix 2.2.2 in [18F]fluorine-labelled radiopharmaceuticals by rapid-resolution liquid chromatography.

PubMed

Lao, Yexing; Yang, Cuiping; Zou, Wei; Gan, Manquan; Chen, Ping; Su, Weiwei

2012-05-01

The cryptand Kryptofix 2.2.2 is used extensively as a phase-transfer reagent in the preparation of [18F]fluoride-labelled radiopharmaceuticals. However, it has considerable acute toxicity. The aim of this study was to develop and validate a method for rapid (within 1 min), specific and sensitive quantification of Kryptofix 2.2.2 at trace levels. Chromatographic separations were carried out by rapid-resolution liquid chromatography (Agilent ZORBAX SB-C18 rapid-resolution column, 2.1 × 30 mm, 3.5 μm). Tandem mass spectra were acquired using a triple quadrupole mass spectrometer equipped with an electrospray ionization interface. Quantitative mass spectrometric analysis was conducted in positive ion mode and multiple reaction monitoring mode for the m/z 377.3 → 114.1 transition for Kryptofix 2.2.2. The external standard method was used for quantification. The method met the precision and efficiency requirements for PET radiopharmaceuticals, providing satisfactory results for specificity, matrix effect, stability, linearity (0.5-100 ng/ml, r(2)=0.9975), precision (coefficient of variation < 5%), accuracy (relative error < ± 3%), sensitivity (lower limit of quantification=0.5 ng) and detection time (<1 min). Fluorodeoxyglucose (n=6) was analysed, and the Kryptofix 2.2.2 content was found to be well below the maximum permissible levels approved by the US Food and Drug Administration. The developed method has a short analysis time (<1 min) and high sensitivity (lower limit of quantification=0.5 ng/ml) and can be successfully applied to rapid quantification of Kryptofix 2.2.2 at trace levels in fluorodeoxyglucose. This method could also be applied to other [18F]fluorine-labelled radiopharmaceuticals that use Kryptofix 2.2.2 as a phase-transfer reagent.

Development of sputtered CuSbS2 thin films grown by sequential deposition of binary sulfides

NASA Astrophysics Data System (ADS)

Medina-Montes, M. I.; Vieyra-Brito, O.; Mathews, N. R.; Mathew, X.

2018-05-01

In this work, CuSbS2 thin films were developed by annealing binary precursors deposited sequentially by rf magnetron sputtering. The recrystallization process was optimized and the films were extensively characterized using a number of tools such as XRD, Raman, SEM, energy dispersive x-ray spectroscopy, atomic force microscopy, Hall, UV–vis spectroscopy, Ellipsometry, Seebeck, and photoresponse. The influence of annealing temperature on the structure, morphology, elemental composition, optical and electrical properties are reported. Annealing below 350 °C resulted in famatinite (Cu3SbS4) and chalcostibite (CuSbS2) ternaries as well as binary phases. Phase-pure chalcostibite was obtained in the range of 350 °C–375 °C. At 400 °C, although CuSbS2 was predominant, tetrahedrite phase (Cu12Sb4S13) appeared as an additional phase. The elemental composition of the films was slightly sulfur deficient, and the atomic percentages of Cu, Sb and S showed a dependence on annealing temperature. The material properties of the phase-pure CuSbS2 thin films are: optical band gap in the range of 1.5–1.62 eV, absorption coefficient close to 105 cm‑1, atomic ratios of Cu/Sb ∼1 and (Cu + Sb)/S ∼1.2, crystal size 18.3–24.5 nm and grain size 50–300 nm. The films were photo-sensitive, showed p-type semiconductor behavior. Electrical resistivity, carrier density and hole mobility were 94–459 Ω cm, 1.6–7.0 × 1015 cm‑3 and 8.4–9.5 cm2 V‑1 s respectively.

Microstructural evaluation of strained multilayer InAsSb/InSb infrared detectors by transmission electron microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chadda, S.; Datye, A.; Dawson, L.R.

InSb/InAsSb strained layer superlattices (SLS) were grown on (001) InSb substrates by molecular beam epitaxy at 425 [degree]C. The active device consisted of an InAs[sub 0.15]Sb[sub 0.85]/InSb superlattice region embedded within a [ital p]-[ital i]-[ital n] junction. The large lattice mismatch between the active device and the substrate required the growth of a buffer. InAs[sub 0.15]Sb[sub 0.85]/InSb SLS, where the average As content was gradually increased, was used as a buffer. The buffer structure was varied to probe its microstructural effect on the capping device. Three distinct approaches (A, B, and C) were used to grow the buffer. Approach Amore » was a four-step buffer where the average content of As in the superlattice was increased in four equal composition steps. This approach led to a crystal with an extensive network of threading dislocations and microcracks. Approach B was to change the average composition in five equal composition steps, thereby decreasing the misfit at the interfaces between composition steps. This led to a decrease in the threading dislocation density but microscopic cracks were still evident. The last approach (C) was to employ migration enhanced epitaxy (MEE) for the growth of the five-step buffer. Samples grown by employing MEE revealed no microcracks but they contained a high density of unusual wiggly'' dislocations at the buffer/device interface. Detailed microstructural analysis by transmission electron microscopy is presented.« less

Identification and quantification of 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones in Chinese eaglewood by HPLC with diode array detection and MS.

PubMed

Li, Jun; Chen, Dong; Jiang, Yong; Zhang, Qian; Zhang, Liang; Tu, Peng-Fei

2013-12-01

A sensitive and reliable HPLC coupled with diode array detection and MS method was developed and validated for the first time to simultaneously identify and quantify eight characteristic 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones (THPECs) in Chinese eaglewood. Chromatographic separation was performed on a Zorbax SB C18 column with a gradient of acetonitrile/0.1% formic acid/water as the mobile phase. The MS fragmentation behavior of THPECs was characterized as the successive neutral loss of two molecules of H2 O ([M+H-18-18](+) ) and then two molecules of CO ([M+H-18-18-28-28](+) ), which could be used to differentiate Chinese eaglewood from counterfeits. Validation of the developed analytical method showed good linearity, satisfactory precision, and good recovery. The established method was successfully applied to the simultaneous determination of eight THPECs in ten batches of Chinese eaglewood, which could be used as a tool for the quality control of Chinese eaglewood. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antiferromagnetism in semiconducting SrMn2Sb2 and BaMn2Sb2 single crystals

NASA Astrophysics Data System (ADS)

Sangeetha, N. S.; Smetana, V.; Mudring, A.-V.; Johnston, D. C.

2018-01-01

Crystals of SrMn2Sb2 and BaMn2Sb2 were grown using Sn flux and characterized by powder and single-crystal x-ray diffraction, respectively, and by single-crystal electrical resistivity ρ , heat capacity Cp, and magnetic susceptibility χ measurements versus temperature T , and magnetization versus field M (H ) isotherm measurements. SrMn2Sb2 adopts the trigonal CaAl2Si2 -type structure, whereas BaMn2Sb2 crystallizes in the tetragonal ThCr2Si2 -type structure. The ρ (T ) data indicate semiconducting behaviors for both compounds with activation energies of ≳0.35 eV for SrMn2Sb2 and 0.16 eV for BaMn2Sb2 . The χ (T ) and Cp(T ) data reveal antiferromagnetic (AFM) ordering at TN = 110 K for SrMn2Sb2 and 450 K for BaMn2Sb2 . The anisotropic χ (T ≤TN) data also show that the ordered moments in SrMn2Sb2 are aligned in the hexagonal a b plane, whereas the ordered moments in BaMn2Sb2 are aligned collinearly along the tetragonal c axis. The a b -plane M (H ) data for SrMn2Sb2 exhibit a continuous metamagnetic transition at low fields 0 Sb2 exhibits no metamagnetic transitions up to 5.5 T. The χ (T ) and C p(T ) data for both SrMn2Sb2 and BaMn2Sb2 indicate strong dynamic short-range AFM correlations above their respective TN up to at least 900 K within a local-moment picture, corresponding to quasi-two-dimensional magnetic behavior. The present results and a survey of the literature for Mn pnictides with the CaAl2Si2 and ThCr2Si2 crystal structures show that the TN values for the CaAl2Si2 -type compounds are much smaller than those for the ThCr2Si2 -type materials.

Strained GaSb/AlAsSb Quantum Wells for p-Channel Field-Effect Transistors

DTIC Science & Technology

2008-01-01

Available online 18 October 2008 PACS: 72.80.Ey 73.61.Ey 81.05.Ea 85.30.Tv Keywords: A3. Molecular beam epitaxy A3. Quantum wells B2. Semiconducting III–V...were grown by molecular beam epitaxy on GaAs substrates. The buffer layer and barrier layers consisted of relaxed AlAsxSb1x. The composition of the...composition in order to control the strain in the GaSb quantum well. The heterostructures studied here are grown by molecular beam epitaxy (MBE) on semi

Analysis and theoretical modeling of 18O enriched carbon dioxide spectrum by CRDS near 1.35 μm: (II) 16O13C18O, 16O13C17O, 12C18O2, 17O12C18O, 12C17O2, 13C18O2 and 17O13C18O

NASA Astrophysics Data System (ADS)

Karlovets, E. V.; Campargue, A.; Kassi, S.; Tashkun, S. A.; Perevalov, V. I.

2017-04-01

This contribution is the second part of the analysis of the room temperature absorption spectrum of 18O enriched carbon dioxide by very high sensitivity Cavity Ring Down spectroscopy between 6977 and 7918 cm-1 (1.43-1.26 μm). Overall, more than 8600 lines belonging to 166 bands of eleven carbon dioxide isotopologues were rovibrationnally assigned. In a first part (Kassi et al. J Quant Spectrosc Radiat Transfer 187 (2017) 414-425, http://dx.doi.org/10.1016/j.jqsrt.2016.09.002), the results relative to mono-substituted isotopologues, 16O12C18O, 16O12C17O, 12C16O2 and 13C16O2, were presented. This second contribution is devoted to the multiply-substituted isotopologues or clumped isotopologues of particular importance in geochemistry: 16O13C18O, 16O13C17O, 12C18O2, 17O12C18O, 12C17O2, 13C18O2 and 17O13C18O. On the basis of the predictions of effective Hamiltonian models, a total of 3195 transitions belonging to 73 bands were rovibrationnally assigned for these seven species. Among the 73 observed bands, 55 are newly reported. All the identified bands correspond to ΔP=10 and 11 series of transitions, where P= 2V1+V2+3V3 is the polyad number (Vi are vibrational quantum numbers). The accurate spectroscopic parameters of 70 bands have been determined from the standard band-by-band analysis. Global fits of the measured line intensities of the ΔP=10 series of transitions of 17O12C18O and 16O13C18O and of the ΔP=11 series of transitions of 12C18O2, 17O12C18O, 16O13C18O and 13C18O2 were performed to determine the corresponding sets of the effective dipole moment parameters.

Effects of Sb Content (x) on (Bi(1-x)Sb(x))2Te3 Thermoelectric Thin Film Deposited by Effusion Cell Evaporator.

PubMed

Yong, Ho; Na, Sekwon; Gang, Jun-Gu; Jeon, Seong-Jae; Hyun, Seungmin; Lee, Hoo-Jeong

2015-10-01

This paper investigates the effects of the Sb content (x) on (Bi(1-x)Sb(x))2Te3 thermoelectric films with x changing widely from 0 (Sb2Te3) to 1 (Bi2Te3). First, the XRD analysis discloses that with the Sb content (x) increasing, the phase changed gradually from Bi2Te3 to Sb2Te3 as Sb atoms replaced substitutionally Bi atoms. Further microstructure analysis reveals that an extensive grain growth occurred during post-annealing for the samples with high Sb contents. According to the measurement of electrical and thermoelectric properties, the polarity of the charge carrier and Seebeck coefficient switched n-type to p-type in the range of x = 0.45~0.63. For the n-type samples, the power factor is highest when x = 0.18 around 46.01 μW/K(2) whereas Sb2Te3, for the p-type samples, shows the highest value, 62.48 μW/K(2)cm.

Sb content dependent thermoelectric properties of the p-type ZnO:Sb films fabricated by oxidation method

NASA Astrophysics Data System (ADS)

Li, Guojian; Lin, Xiao; Liu, Shiying; Jia, Baohai; Wang, Qiang

2018-05-01

It is important to fabricate stable p-type ZnO:Sb thermoelectric (TE) films for the p-n homojunction TE devices that convert waste heat directly into electricity. In this study, the ZnO:Sb films with different Sb contents were prepared by oxidizing evaporated Zn-Sb films in oxygen. The film with a high Sb content (5.32%) is easy to form Zn4Sb3 and ZnSb compound in the wurtzite ZnO. The resistivity has a sharply reduction with the Sb content from 0.228 Ω·m of 3.95% Sb to 4.68 × 10-5 Ω·m of 5.32% Sb. The lowest resistivity is lower at least one order of magnitude than the results of others with the similar Sb content. The Seebeck coefficient indicates that the 5.32% Sb film remains stable p-type conduction. The carrier concentration is about 1020 cm-3 and is higher at least one order of magnitude than the other results. Raman analysis indicates that the peak of E2high related O sublattice vibrations indicates that the O sites are substituted by Sb3+ ions, which increases the carrier concentration. However, the mobility is relatively weak because the intrinsic host lattice defects activated as vibrating complexes. The power factor of the p-type ZnO:Sb of the 5.32% Sb film at 427 °C is 46.79 μW/m·K2.

Growth and characterization of AlInAsSb layers lattice-matched to GaSb

NASA Astrophysics Data System (ADS)

Tournet, J.; Rouillard, Y.; Tournié, E.

2017-11-01

We report on the growth by solid-source MBE of random-alloy AlxIn1-xAsySb1-y layers lattice-matched to (0 0 1)-GaSb substrates, with xAl ∈ [0.25; 0.75]. The samples quality and morphology were characterized by X-ray diffraction, Nomarski microscopy and atomic force microscopy. Layers grown at 400 °C demonstrated smooth surfaces and no sign of phase decomposition. Samples with xAl ≤ 0.60 demonstrated photoluminescence (PL) at 300 K whereas samples with higher Al content only demonstrated PL at low temperature. Samples grown at 430 °C, in contrast, exhibited PL at low temperature only, whatever their composition. Inferred bandgap energies corroborate the estimation of a non-null quaternary bowing parameter made by Donati, Kaspi and Malloy in Journal of Applied Physics 94 (2003) 5814. Upon annealing, the PL peak energies increased, getting even closer to the theoretical values. These results are in agreement with recently published results on digital AlInAsSb alloys. Our work, which reports the first evidence for PL emission from random-alloy AlInAsSb layers lattice-matched to GaSb, opens the way to their use in optoelectronic devices.

Metalorganic chemical vapor deposition growth of InAs/GaSb type II superlattices with controllable AsxSb1-x interfaces

PubMed Central

2012-01-01

InAs/GaSb type II superlattices were grown on (100) GaSb substrates by metalorganic chemical vapor deposition (MOCVD). A plane of mixed As and Sb atoms connecting the InAs and GaSb layers was introduced to compensate the tensile strain created by the InAs layer in the SL. Characterizations of the samples by atomic force microscopy and high-resolution X-ray diffraction demonstrate flat surface morphology and good crystalline quality. The lattice mismatch of approximately 0.18% between the SL and GaSb substrate is small compared to the MOCVD-grown supperlattice samples reported to date in the literature. Considerable optical absorption in 2- to 8-μm infrared region has been realized. PACS: 78.67.Pt; 81.15.Gh; 63.22.Np; 81.05.Ea PMID:22373387

Quantum dots grown in the InSb/GaSb system by liquid-phase epitaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkhomenko, Ya. A.; Dement’ev, P. A.; Moiseev, K. D., E-mail: mkd@iropt2.ioffe.rssi.ru

2016-07-15

The first results of the liquid-phase epitaxial growth of quantum dots in the InSb/GaSb system and atomic-force microscopy data on the structural characteristics of the quantum dots are reported. It is shown that the surface density, shape, and size of nanoislands depend on the deposition temperature and the chemical properties of the matrix surface. Arrays of InSb quantum dots on GaSb (001) substrates are produced in the temperature range T = 450–465°C. The average dimensions of the quantum dots correspond to a height of h = 3 nm and a base dimension of D = 30 nm; the surface densitymore » is 3 × 10{sup 9} cm{sup –2}.« less

Quench hardening of Sb0.2 Bi1.8Te3, Bi2Te2.8Se0.2 and Sn0.2 Bi1.8Te3 single crystals

NASA Astrophysics Data System (ADS)

Soni, P. H.

2018-02-01

The V2-VI3 intermetallics are narrow band gap semiconductors and well known for their thermoelectric properties. They therefore offer a convenient route to tune band gap for manipulating thermoelectric parameters. The V group element Sb can be fruitfully used to substitute Bi in various proportions thus forming a psuedobinary solid solution. The electronic in general and the thermoelectric properties in particular of this psuedobinary have been amply reported. However there are no reports found on mechanical properties. I have used Sb0.2 Bi1.8Te3, Bi2Te2.8Se0.2 and Sn0.2 Bi1.8Te3single crystals grown using Bridgman technique for the quenching treatment followed by hardness testing. Vickers hardness tests were conducted on the cleavage planes of the crystals quenched from various high temperatures and the quench hardenening coefficient values have been determined. The hardness tests were carried out at various applied loads also to explore load dependence of the measured hardness. The results are reported in the paper.

The reaction mechanism of SnSb and Sb thin film anodes for Na-ion batteries studied by X-ray diffraction, 119Sn and 121Sb Mössbauer spectroscopies

DOE PAGES

Baggetto, Loïc; Hah, Hien-Yoong; Jumas, Jean-Claude; ...

2014-06-01

The electrochemical reaction of Sb and SnSb anode materials with Na results in the formation of amorphous materials. To understand the resulting phases and electrochemical capacities we studied the reaction products local order using 119Sn and 121Sb Mössbauer spectroscopies in conjunction with measurements performed on model powder compounds of Na-Sn and Na-Sb to further clarify the reactions steps. For pure Sb the discharge (sodiation) starts with the formation of an amorphous phase composed of atomic environments similar to those found in NaSb, and proceeds further by the formation of environments similar to that present in Na 3Sb. The reversible reactionmore » takes place during a large portion of the charge process. At full charge the anode material still contains a substantial fraction of Na, which explains the lack of recrystallization into crystalline Sb. The reaction of SnSb yields Na 3Sb crystalline phase at full discharge at higher temperatures (65 and 95°C) while the room temperature reaction yields amorphous compounds. The electrochemically-driven, solid-state amorphization reaction occurring at room temperature is governed by the simultaneous formation of Na-coordinated Sn and Sb environments, as monitored by the decrease (increase) of the 119Sn ( 121Sb) Mössbauer isomer shifts. Overall, the monitoring of the hyperfine parameters enables to correlate the changes in Na content to the individual Sn and Sb local chemical environments.« less

The two-dimensional tunnel structures of K3Sb5O14 and K2Sb4O11

NASA Technical Reports Server (NTRS)

Hong, H. Y.-P.

1974-01-01

The structures of K3Sb5O14 and K2Sb4O11 have been solved by the single-crystal X-ray direct method and the heavy-atom method, respectively. The structure of K3Sb5O14 is orthorhombic, with space group Pbam and cell parameters a = 24.247 (4), b = 7.157 (2), c = 7.334 (2) A, Z = 4. The structure of K2Sb4O11 is monoclinic, with space group C2/m and cell parameters a = 19.473 (4), b = 7.542 (1), c = 7.198 (1) A, beta = 94.82 (2) deg, Z = 4. A full-matrix least-squares refinement gave R = 0.072 and R = 0.067, respectively. In both structures, oxygen atoms form an octahedron around each Sb atom and an irregular polyhedron around each K atom. By sharing corners and edges, the octahedra form a skeleton network having intersecting b-axis and c-axis tunnels. The K(+) ions, which have more than ten oxygen near neighbors, are located in these tunnels. Evidence for K(+)-ion transport within and between tunnels comes from ion exchange of the alkali ions in molten salts and anisotropic temperature factors that are anomalously large in the direction of the tunnels.

Chemical Substitution-Induced and Competitive Formation of 6H and 3C Perovskite Structures in Ba3-xSrxZnSb2O9: The Coexistence of Two Perovskites in 0.3 ≤ x ≤ 1.0.

PubMed

Li, Jing; Jiang, Pengfei; Gao, Wenliang; Cong, Rihong; Yang, Tao

2017-11-20

6H and 3C perovskites are important prototype structures in materials science. We systemically studied the structural evolution induced by the Sr 2+ -to-Ba 2+ substitution to the parent 6H perovskite Ba 3 ZnSb 2 O 9 . The 6H perovskite is only stable in the narrow range of x ≤ 0.2, which attributes to the impressibility of [Sb 2 O 9 ]. The preference of 90° Sb-O-Sb connection and the strong Sb 5+ -Sb 5+ electrostatic repulsion in [Sb 2 O 9 ] are competitive factors to stabilize or destabilize the 6H structure when chemical pressure was introduced by Sr 2+ incorporation. Therefore, in the following, a wide two-phase region containing 1:2 ordered 6H-Ba 2.8 Sr 0.2 ZnSb 2 O 9 and rock-salt ordered 3C-Ba 2 SrZnSb 2 O 9 was observed (0.3 ≤ x ≤ 1.0). In the final, the successive symmetry descending was established from cubic (Fm3̅m, 1.3 ≤ x ≤ 1.8) to tetragonal (I4/m, 2.0 ≤ x ≤ 2.4), and finally to monoclinic (I2/m, 2.6 ≤ x ≤ 3.0). Here we proved that the electronic configurations of B-site cations, with either empty, partially, or fully filled d-shell, would also affect the structure stabilization, through the orientation preference of the B-O covalent bonding. Our investigation gives a deeper understanding of the factors to the competitive formation of perovskite structures, facilitating the fine manipulation on their physical properties.

Antimony in recent, ombrotrophic peat from Switzerland and Scotland: Comparison with natural background values (5,320 to 8,020 14C yr BP) and implications for the global atmospheric Sb cycle

NASA Astrophysics Data System (ADS)

Shotyk, William; Krachler, Michael; Chen, Bin

2004-03-01

The lowest concentrations, atmospheric fluxes, and enrichments of Sb in a Swiss bog were found in peat samples dating from 8,020 to 5,320 14C yr BP when Sb inputs were proportional to those of Sc and effectively controlled by deposition of soil dust. For comparison with these ancient samples, modern peat samples from five rural areas of Switzerland and two remote areas of Scotland and Shetland are highly contaminated with Sb, with enrichments of the order of 30 to 80 times. "Lithogenic" Sb concentrations calculated using the Sc concentrations and background Sb/Sc ratio are dwarfed at all sites by "anthropogenic" Sb. The chronology and intensity of the Sb enrichments are in many ways similar to those of Pb which indicates that (1) Sb, like Pb, is well preserved in ombrotrophic peat and (2) the extent of human impacts on the geochemical cycle of Sb is comparable to that of Pb. The similar distribution of Sb and Pb can be explained in terms of their chemical and mineralogical associations, with most lead minerals being rich in Sb. Assuming that the "background" Sb flux (0.35 μg/m2/yr) from the Swiss bog is representative of preanthropogenic deposition rates worldwide, the global flux of natural Sb is estimated at 154 T/a. Using the natural Pb flux published by [1987] of 2600 T/a and the "background" Pb/Sb ratio (29) of the preanthropogenic peat samples, the global flux of natural Sb is estimated at 90 T/a. Either way, these values (90 to 154 T/a) are considerably lower than the current estimate of natural Sb to the global atmosphere (2400 T/a) published by [2001]. Assuming that the current estimate of anthropogenic Sb to the global atmosphere (1600 T/a) is correct [, 2001], the ratio of anthropogenic to natural Sb emissions is on the order of 10 to 18. Taken together, the data from modern and ancient peat samples suggests that the impact of human activities on the global geochemical cycle of Sb may have been underestimated by an order of magnitude. Like Pb, Sb has no

Ultraviolet and visible range plasmonics in the topological insulator Bi1.5Sb0.5Te1.8Se1.2

NASA Astrophysics Data System (ADS)

Ou, Jun-Yu; So, Jin-Kyu; Adamo, Giorgio; Sulaev, Azat; Wang, Lan; Zheludev, Nikolay I.

2014-10-01

The development of metamaterials, data processing circuits and sensors for the visible and ultraviolet parts of the spectrum is hampered by the lack of low-loss media supporting plasmonic excitations. This has driven the intense search for plasmonic materials beyond noble metals. Here we show that the semiconductor Bi1.5Sb0.5Te1.8Se1.2, also known as a topological insulator, is also a good plasmonic material in the blue-ultraviolet range, in addition to the already-investigated terahertz frequency range. Metamaterials fabricated from Bi1.5Sb0.5Te1.8Se1.2 show plasmonic resonances from 350 to 550 nm, while surface gratings exhibit cathodoluminescent peaks from 230 to 1,050 nm. The observed plasmonic response is attributed to the combination of bulk charge carriers from interband transitions and surface charge carriers of the topological insulator. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible range plasmonics can be directly integrated with electronics.

Preparation, spectroscopic characterization and antimicrobial activities of mixed metal (Sb and Bi) bridged derivatives with mixed sulfur donor ligands

NASA Astrophysics Data System (ADS)

Joshi, Sapana; Chauhan, H. P. S.; Carpenter, Nitin

2017-01-01

This article explores the syntheses of six mixed metal derivatives of antimony(III) and bismuth(III) by the reaction of ethane-1,2-dithiol and metal bis derivatives of dithiocarbamates and/or dithiophosphates ligands in 1:1:1 M stoichiometry. These derivatives have been characterized by physicochemical [elemental analysis (C, H, N, S, Sb and Bi), molecular weight and melting point determinations], spectral [UV-Visible, FTIR, NMR (1H, 13C and 31P)], powder X-ray diffraction studies. These derivatives have nano-ranged crystallite size (8.18-18.04 nm) with monoclinic crystal system. All the synthesized derivatives have two metal centers (Sb and Bi) which elevate the zone of inhibition against four bacterial and two fungal species as compared to single metal species (metal precursors) as well as standard drugs.

Self-assembling of impurity clusters in AlN:(Ga, BV, CV), (BV, CV = P, As; P, Sb; As, Sb)

NASA Astrophysics Data System (ADS)

Elyukhin, V. A.

2015-11-01

The self-assembling conditions of arrays of tetrahedral impurity clusters of two types in zinc blende AlN:(Ga, BV, CV), (BV, CV = P, As; P, Sb; As, Sb) are represented. Doping with one cation and two anion isoelectronic impurities transforms AlN into AlN-rich GaxAl1-xBVyCVzN1-y-z alloy of GaBV, GaCV, GaN, AlBV, AlCV and AlN. The cause of self-assembling is the preference of GaBV, GaCV and AlN bonding over that of GaN, AlBV, AlCV. The conditions are considered from 0 °C to 1000 °C in the dilute and ultra dilute limits for the cation and anion impurities, correspondingly. The temperature ranges between the cluster occurrence and self-assembling completion when the same anion impurities are in clusters are very small. 1P4Ga and 1As4Ga cluster occurrence temperatures are equal, correspondingly, to 797 °C and 736 °C at Ga content 2% and P and As contents 0.01%. 1P4Ga and 1Sb4Ga cluster occurrence temperatures are equal, correspondingly, to 976 °C and 736 °C at the same impurity contents. The cluster densities in AlN:(Ga, As, Sb) are close to those in AlN:(Ga, P, Sb). The results demonstrate that studied semiconductors are promising materials to produce arrays of identical ∼1 nm low band gap objects of two types embedded in the wide band gap matrix.

High-performance liquid chromatography-electrospray ionization mass spectrometry determination of sodium ferulate in human plasma.

PubMed

Yang, Cheng; Tian, Yuan; Zhang, Zunjian; Xu, Fengguo; Chen, Yun

2007-02-19

A selective and sensitive high-performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the determination of sodium ferulate in human plasma. The sample preparation was a liquid-liquid extraction and chromatographic separation was achieved with an Agilent ZORBAX SB-C(18) (3.5 microm, 100 mm x 3.0 mm) column, using a mobile phase of methanol-0.05% acetic acid 40:60 (v/v). Standard curves were linear (r(2)=0.9982) over the concentration range of 0.007-4.63 nM/ml and had acceptable accuracy and precision. The within- and between-batch precisions were within 12% relative standard deviation. The lower limit of quantification (LLOQ) was 0.007 nM/ml. The validated HPLC-ESI-MS method has been used successfully to study sodium ferulate pharmacokinetics, bioavailability and bioequivalence in 20 healthy volunteers.

[Simultaneous determination of aspartame and alitame in jellies and preserved fruits by HPLC].

PubMed

Jiang, Dingguo; Fang, Congrong; Yang, Dajin

2012-05-01

To establish a determination method for aspartame and alitame in jellies and preserved fruits. Aspartame and alitame in jellies were extracted with 80% methanol at 70 degrees C. Preserved fruits were homogenized with water and then were extracted with 50% methanol. A chromatographic column Zorbax SB-C18 was used; the mobile phase was methanol/water (40 + 60, volume ratio), and a diode array detector was used for the detection at wavelength 200 nm. The limits of quantification of aspartame and alitame were both 8 mg/kg for jellies and both 20 mg/kg for preserved fruits; the calibration curves were linear in the range of tested concentration. The correlation coefficients were better than 0.9996. The average recovery rates were in the range of 98.1% -101.2%, the relative standard deviations were 2.21% - 4.10%. The method is simple, practical, accurate, reliable and successful in the determination of aspartame and alitame in jellies and preserved fruits from various brands on markets.

Synthesis and Initial in Vivo Studies with [11C]SB-216763: The First Radiolabeled Brain Penetrative Inhibitor of GSK-3

PubMed Central

2015-01-01

Quantifying glycogen synthase kinase-3 (GSK-3) activity in vivo using positron emission tomography (PET) imaging is of interest because dysregulation of GSK-3 is implicated in numerous diseases and neurological disorders for which GSK-3 inhibitors are being considered as therapeutic strategies. Previous PET radiotracers for GSK-3 have been reported, but none of the published examples cross the blood–brain barrier. Therefore, we have an ongoing interest in developing a brain penetrating radiotracer for GSK-3. To this end, we were interested in synthesis and preclinical evaluation of [11C]SB-216763, a high-affinity inhibitor of GSK-3 (Ki = 9 nM; IC50 = 34 nM). Initial radiosyntheses of [11C]SB-216763 proved ineffective in our hands because of competing [3 + 3] sigmatropic shifts. Therefore, we have developed a novel one-pot two-step synthesis of [11C]SB-216763 from a 2,4-dimethoxybenzyl-protected maleimide precursor, which provided high specific activity [11C]SB-216763 in 1% noncorrected radiochemical yield (based upon [11C]CH3I) and 97–100% radiochemical purity (n = 7). Initial preclinical evaluation in rodent and nonhuman primate PET imaging studies revealed high initial brain uptake (peak rodent SUV = 2.5 @ 3 min postinjection; peak nonhuman primate SUV = 1.9 @ 5 min postinjection) followed by washout. Brain uptake was highest in thalamus, striatum, cortex, and cerebellum, areas known to be rich in GSK-3. These results make the arylindolemaleimide skeleton our lead scaffold for developing a PET radiotracer for quantification of GSK-3 density in vivo and ultimately translating it into clinical use. PMID:26005531

GaSbBi/GaSb quantum well laser diodes

NASA Astrophysics Data System (ADS)

Delorme, O.; Cerutti, L.; Luna, E.; Narcy, G.; Trampert, A.; Tournié, E.; Rodriguez, J.-B.

2017-05-01

We report on the structural and optical properties of GaSbBi single layers and GaSbBi/GaSb quantum well heterostructures grown by molecular beam epitaxy on GaSb substrates. Excellent crystal quality and room-temperature photoluminescence are achieved in both cases. We demonstrate laser operation from laser diodes with an active zone composed of three GaSb0.885Bi0.115/GaSb quantum wells. These devices exhibit continuous-wave lasing at 2.5 μm at 80 K, and lasing under pulsed operation at room-temperature near 2.7 μm.

The Influence of Growth Temperature on Sb Incorporation in InAsSb, and the Temperature-dependent Impact of Bi Surfactants

DTIC Science & Technology

2014-01-01

resolution X - ray diffraction (XRD) were collected for all samples, and reciprocal space maps (RSMs) were collected from selected samples. The complete data...exposure. The lines represent the model fit. 19 13 Figure 1. Triple axis x - ray diffraction from the bi-layered InAsSb structures grown on GaSb at...Applied Physics, Structural properties of bismuth‐bearing semiconductor alloys, 63 (1988) 107. 18 12 Figure Captions Figure 1. Triple axis x - ray

InGaAsSb/AlGaAsSb Heterojunction Phototransistors for Infrared Applications

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Abedin, M. N.; Sulima, Oleg V.; Ismail, Syed; Singh, Upendra N.

2006-01-01

High quality infrared (IR) quantum detectors are important for several applications, such as atmospheric remote sensing, chemical detection and absorption spectroscopy. Although several IR detectors are commercially available, with different materials and structures, they provide limited performance regarding the signal-to-noise ratio and the corresponding minimum detectable signal. InGaAsSb/AlGaAsSb heterojunction based phototransistors show strong potential for developing IR sensors with improved performance. In this paper, the performance of a novel npn InGaAsSb/AlGaAsSb heterojunction phototransistor is presented. This performance study is based on experimental characterization of the device dark current, noise and spectral response. Detectivity of 1.7x10(exp 9) cmHz(exp 1/2)/W at 2 microns was obtained at 100 C temperature and 2 V bias voltage. This corresponds to a responsivity of 94.7 A/W and an internal gain of 156 with about 37.7% quantum efficiency. Reducing the temperature to -30 C allows to increase the bias to 3V and enhance the detectivity to 8.7x10(exp 10) cmHz(exp 1/2)/W at the same wavelength, which corresponds to a responsivity of 386.5 A/W and an internal gain of 288.2 with about 83.3% quantum efficiency. The device impulse response and linearity, including the corresponding dynamic range, also are presented. Impulse response analysis indicated a settling time of about 1.1 s at 2V and 100 C, while linearity measurements indicated a constant responsivity in the radiation intensity range of 1.6x10(exp -7) W/sq cm and 31.6 mW/sq cm.

The orexin-1 receptor antagonist SB-334867 decreases anxiety-like behavior and c-Fos expression in the hypothalamus of rats exposed to cat odor.

PubMed

Vanderhaven, M W; Cornish, J L; Staples, L G

2015-02-01

Increasing evidence suggests that the orexin system is involved in modulating anxiety, and we have recently shown that cat odor-induced anxiety in rats is attenuated by the orexin receptor antagonist SB-334867. In the current experiment, c-Fos expression was used to map changes in neuronal activation following SB-334867 administration in the cat odor anxiety model. Male Wistar rats were exposed to cat odor with or without SB-334867 pre-treatment (10 mg/kg, i.p.). A naïve control group not exposed to cat odor was also used. Following cat odor exposure, brains were processed for c-Fos expression. Vehicle-treated rats showed an increase in anxiety-like behaviors (increased hiding and decreased approach toward the cat odor), and increased c-Fos expression in the posteroventral medial amygdala (MePV), paraventricular hypothalamus (PVN) and dorsal premammillary nucleus (PMd). In rats pretreated with SB-334867, approach scores increased and c-Fos expression decreased in the PVN and PMd. These results provide both behavioral and neuroanatomical evidence for the attenuation of cat odor-induced anxiety in rats via the orexin system. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Unusual centrosymmetric structure of [M(18-crown-6)](+) (M = Rb, Cs and NH4) complexes stabilized in an environment of hexachloridoantimonate(V) anions.

PubMed

Ponomarova, Vira V; Rusanova, Julia A; Rusanov, Eduard B; Domasevitch, Konstantin V

2015-10-01

In (1,4,7,10,13,16-hexaoxacyclooctadecane)rubidium hexachloridoantimonate(V), [Rb(C12H24O6)][SbCl6], (1), and its isomorphous caesium {(1,4,7,10,13,16-hexaoxacyclooctadecane)caesium hexachloridoantimonate(V), [Cs(C12H24O6)][SbCl6]}, (2), and ammonium {ammonium hexachloridoantimonate(V)-1,4,7,10,13,16-hexaoxacyclooctadecane (1/1), (NH4)[SbCl6]·C12H24O6}, (3), analogues, the hexachloridoantimonate(V) anions and 18-crown-6 molecules reside across -3 axes passing through the Sb atoms and the centroids of the 18-crown-6 groups, both of which coincide with centres of inversion. The Rb(+) [in (1)], Cs(+) [in (2)] and NH4(+) [in (3)] cations are situated inside the cavity of the 18-crown-6 ring; they are situated on -3 axes and are equally disordered about centres of inversion, deviating from the centroid of the 18-crown-6 molecule by 0.4808 (13), 0.9344 (7) and 0.515 (8) Å, respectively. Interaction of the ammonium cation and the 18-crown-6 group is supported by three equivalent hydrogen bonds [N...O = 2.928 (3) Å and N-H...O = 162°]. The centrosymmetric structure of [Cs(18-crown-6)](+), with the large Cs(+) cation approaching the centre of the ligand cavity, is unprecedented and accompanied by unusually short Cs-O bonds [2.939 (2) and 3.091 (2) Å]. For all three compounds, the [M(18-crown-6)](+) cations and [SbCl6](-) anions afford linear stacks along the c axis, with the cationic complexes embedded between pairs of inversion-related anions.

MOVPE prepared InAs/GaAs quantum dots covered by GaAsSb layer with long wavelength emission at 1.8 μm

NASA Astrophysics Data System (ADS)

Zíková, Markéta; Hospodková, Alice; Pangrác, Jiří; Oswald, Jiří; Krčil, Pavel; Hulicius, Eduard; Komninou, Philomela; Kioseoglou, Joseph

2015-03-01

Preparation and properties of InAs/GaAs quantum dots (QDs) prepared by the MOVPE technology covered by GaAsSb strain reducing layer (SRL) with extremely long emission wavelength at 1.8 μm will be presented. Increase of the emission wavelength was achieved by the introduction of GaAsSb SRL with Sb content of about 30% in the solid phase. The high Sb concentration in the SRL causes the preservation of QD size, which is about 15 nm wide at the base and 5 nm high. Increased QD size increases the photoluminescence (PL) wavelength. Furthermore, high content of antimony leads to a creation of type II heterostructure for which a redshift of the PL wavelength and decrease of the PL intensity are typical. Low PL intensity may complicate light emitting applications; however fast separation of carriers in the type II structure is an advantage for detector or solar cell application, especially with the long working wavelength. With respect to the perspective application of this structure, the photocurrent (PC) measurement was chosen as the complementary characterization method. A depression of PC for quantum well wavelength region (approximately 900-1200 nm) was observed for positive bias, while the PC from QDs (over 1200 nm) is not sensitive to the electric field orientation at all. An explanation of this unexpected phenomenon is suggested.

High-temperature luminescence in an n-GaSb/n-InGaAsSb/p-AlGaAsSb light-emitting heterostructure with a high potential barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petukhov, A. A., E-mail: andrey-rus29@rambler.ru; Zhurtanov, B. E.; Kalinina, K. V.

2013-09-15

The electroluminescent properties of an n-GaSb/n-InGaAsSb/p-AlGaAsSb heterostructure with a high potential barrier in the conduction band (large conduction-band offset) at the n-GaSb/n-InGaAsSb type-II heterointerface ({Delta}E{sub c} = 0.79 eV) are studied. Two bands with peaks at 0.28 and 0.64 eV at 300 K, associated with radiative recombination in n-InGaAsSb and n-GaSb, respectively, are observed in the electroluminescence (EL) spectrum. In the entire temperature range under study, T = 290-480 K, additional electron-hole pairs are formed in the n-InGaAsSb active region by impact ionization with hot electrons heated as a result of the conduction-band offset. These pairs contribute to radiative recombination,more » which leads to a nonlinear increase in the EL intensity and output optical power with increasing pump current. A superlinear increase in the emission power of the long-wavelength band is observed upon heating in the temperature range T = 290-345 K, and a linear increase is observed at T > 345 K. This work for the first time reports an increase in the emission power of a light-emitting diode structure with increasing temperature. It is shown that this rise is caused by a decrease in the threshold energy of the impact ionization due to narrowing of the band gap of the active region.« less

Highly efficient and mild electrochemical mineralization of long-chain perfluorocarboxylic acids (C9-C10) by Ti/SnO2-Sb-Ce, Ti/SnO2-Sb/Ce-PbO2, and Ti/BDD electrodes.

PubMed

Lin, Hui; Niu, Junfeng; Xu, Jiale; Huang, Haiou; Li, Duo; Yue, Zhihan; Feng, Chenghong

2013-11-19

The electrochemical mineralization of environmentally persistent long-chain perfluorinated carboxylic acids (PFCAs), i.e., perfluorononanoic acid (C8F17COOH, PFNA) and perfluorodecanoic acid (C9F19COOH, PFDA) was investigated in aqueous solutions (0.25 mmol L(-1)) over Ti/SnO2-Sb-Ce (SnO2), Ti/SnO2-Sb/Ce-PbO2 (PbO2), and Ti/BDD (BDD) anodes under galvanostatic control at room temperature. Based on PFCA decay rate, total organic carbon (TOC) reduction, defluorination ratio, safety, and energy consumption, the performance of PbO2 electrode was comparable with that of BDD electrode. After 180 min electrolysis, the PFNA removals on BDD and PbO2 electrodes were 98.7 ± 0.4% and 97.1 ± 1.0%, respectively, while the corresponding PFDA removals were 96.0 ± 1.4% and 92.2 ± 1.9%. SnO2 electrode yielded lower PFCA removals and led to notable secondary pollution by Sb ions. The primary mineralization product, F(-), as well as trace amounts of intermediate PFCAs with shortened chain lengths, were detected in aqueous solution after electrolysis. On the basis of these results, a degradation mechanism including three potential routes is proposed: via formation of short-chain PFCAs by stepwise removal of CF2; direct mineralization to CO2 and HF; conversion to volatile fluorinated organic compounds. The results presented here demonstrate that electrochemical technique exhibits high efficiency in mineralizing PFNA and PFDA under mild conditions, and is promising for the treatment of long-chain PFCAs in wastewater.

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

In-plane electrical transport in n-type selectively doped GaSb/AlGaSb multiquantum wells

NASA Astrophysics Data System (ADS)

Ghezzi, C.; Cioce, B.; Magnanini, R.; Parisini, A.

2001-11-01

Results are reported regarding in-plane electrical transport in n-type selectively doped GaSb/AlGaSb multiquantum wells. In the samples, which were grown by molecular beam epitaxy, only the central regions of the Al0.40Ga0.60Sb barriers were Te doped. Low-field, low-temperature Hall measurements in the dark demonstrated the presence in the GaSb wells of a degenerate electron gas with nonzero occupancy only for the lowest miniband. A positive persistent photoconductivity effect, related to the DX character of the Te impurity, was also observed. This behavior enabled the μ electron mobility to be measured at T=10 K as a function of the nS sheet carrier density. Since the experimental data were consistent with a dominant role of the interface roughness scattering in the limiting of μ, the height, Δ, and the lateral size, Λ, of the interface roughness were determined from the analysis of the μ=μ(nS) dependence. Acceptable values of Δ were obtained, consistent with results of structural investigations in single quantum well samples of GaSb/Al0.40Ga0.60Sb [E. Kh. Mukhamedzhanov, C. Bocchi, S. Franchi, A. Baraldi, R. Magnanini, and L. Nasi, J. Appl. Phys. 87, 4234 (2000)].

Crystal growth and physical properties of SrCu2As2, SrCu2Sb2, and BaCu2Sb2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anand, V.K.; Perera, P. Kanchana; Pandey, Abhishek

2012-06-25

We report the growth of single crystals of SrCu2As2, SrCu2Sb2, SrCu2(As0.84Sb0.16)2, and BaCu2Sb2 using the self-flux technique and their structural, magnetic, thermal, and transport properties that were investigated by powder x-ray diffraction (XRD), magnetic susceptibility χ, specific heat Cp, and electrical resistivity ρ measurements versus temperature T from 1.8 to 350 K. Rietveld refinements of XRD patterns for crushed crystals confirm that SrCu2As2 crystallizes in the ThCr2Si2-type body-centered tetragonal structure (space group I4/mmm) and SrCu2Sb2 crystallizes in the CaBe2Ge2-type primitive tetragonal structure (space group P4/nmm). However, as reported previously, BaCu2Sb2 is found to have a large unit cell consisting ofmore » three blocks. Here a ThCr2Si2-type block is sandwiched between two CaBe2Ge2-type blocks along the c axis with an overall symmetry of I4/mmm, as reported, but likely with a monoclinic distortion. The χ data of all these compounds are diamagnetic and reveal nearly T-independent anisotropic behavior. The χ of SrCu2As2 is found to be larger in the ab plane than along the c axis, as also previously reported for pure and doped BaFe2As2, whereas the χ values of SrCu2Sb2 and BaCu2Sb2 are larger along the c axis. This difference in anisotropy appears to arise from the differences between the crystal structures. The finite values of the Sommerfeld linear specific heat coefficients γ and the T dependences of ρ reveal metallic character of all four compounds. The electronic and magnetic properties indicate that these compounds are sp metals with Cu in the nonmagnetic 3d10 electronic configuration corresponding to the oxidation state Cu+1, as previously predicted theoretically for SrCu2As2 by Singh [ Phys. Rev. B 79 153102 (2009)]. We present a brief review of theoretical and experimental work on the doping character of transition metals for Fe in BaFe2As2. The As–As covalent interlayer bond distances in the collapsed-tetragonal (Ca

Temperature dependent lattice constant of InSb above room temperature

NASA Astrophysics Data System (ADS)

Breivik, Magnus; Nilsen, Tron Arne; Fimland, Bjørn-Ove

2013-10-01

Using temperature dependent X-ray diffraction on two InSb single crystalline substrates, the bulk lattice constant of InSb was determined between 32 and 325 °C. A polynomial function was fitted to the data: a(T)=6.4791+3.28×10-5×T+1.02×10-8×T2 Å (T in °C), which gives slightly higher values than previously published (which go up to 62 °C). From the fit, the thermal expansion of InSb was calculated to be α(T)=5.062×10-6+3.15×10-9×T K-1 (T in °C). We found that the thermal expansion coefficient is higher than previously published values above 100 °C (more than 10% higher at 325 °C).

[Simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials by solid phase extraction-high performance liquid chromatography].

PubMed

Zhang, Juzhou; Li, Jing; Shao, Dongliang; Yao, Bangben; Jiang, Junshu

2012-02-01

An effective high performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials. The food packaging samples were firstly extracted by methanol-ethyl acetate, and then purified by a C18 solid-phase extraction (SPE) column. The target compounds were separated on a ZORBAX SB-C18 column (250 mm x 4.6 mm, 5 microm) in gradient elution mode using methanol and water as mobile phases. The detection wavelength was at 310 nm. The linear plots of the nine ultraviolet stabilizers were obtained between 0.2 and 10 mg/L, with the correlation coefficients of above 0. 999 for the nine ultraviolet stabilizers. The limits of detection for this method were in the range from 0.05 to 0.1 mg/L. The recoveries spiked in commercial food plastic packaging materials were in the range of 70.2% - 89.0% with the relative standard deviations of 0.4% - 4.5%. The results indicated that the method is simple, accurate, and suitable for the simultaneous determination of the nine ultraviolet stabilizers in food plastic packaging materials.

The polarization of Sb overlayers on NiMnSb(100)

NASA Astrophysics Data System (ADS)

Komesu, Takashi; Borca, C. N.; Jeong, Hae-Kyung; Dowben, P. A.; Ristoiu, Delia; Nozières, J. P.; Stadler, Shane; Idzerda, Y. U.

2000-08-01

We have investigated the induced polarization of paramagnetic Sb overlayers on the Heusler alloy NiMnSb. From combined X-ray absorption spectroscopy (XAS) and spin-polarized inverse photoemission spectroscopy (SPIPES), we can assign some of the unoccupied states of the Heusler alloy NiMnSb. With increasing thickness of the Sb overlayer, there is a decline in the density of states near the Fermi energy, as expected for a semimetal overlayer on a metallic substrate. While the Sb is polarized by the ferromagnetic NiMnSb substrate, consistent with the expectations of mean field theory, the polarization at the center of the surface/overlayer Brillouin zone cannot be easily related to the induced magnetization.

The synergistic effect of non-stoichiometry and Sb-doping on air-stable α-CsPbI3 for efficient carbon-based perovskite solar cells.

PubMed

Xiang, Sisi; Li, Weiping; Wei, Ya; Liu, Jiaming; Liu, Huicong; Zhu, Liqun; Chen, Haining

2018-05-18

α-CsPbI3 with the most suitable band gap for all-inorganic perovskite solar cell (PSC) application faces an issue of phase instability at low temperature in an air atmosphere. Herein, through stoichiometric investigation, α-CsPbI3 is successfully obtained with excess CsI at 110 °C in an air atmosphere. By doping α-CsPbI3 with Sb, phase stability is further enhanced and the film morphology is also improved. Carbon-based perovskite solar cells (C-PSCs) based on CsPb0.96Sb0.04I3 achieve a promising power conversion efficiency (PCE) of 5.18%, a record value for α-CsPbI3-based PSCs without hole transport materials. Significantly, the CsPb0.96Sb0.04I3 C-PSCs retain 93% of the initial PCE after 37 days of storage in an air atmosphere. Therefore, the synergistic effect of non-stoichiometry and Sb-doping presents a promising strategy to design all-inorganic lead halide PSCs with high performance and stability.

Surface cleaning and pure nitridation of GaSb by in-situ plasma processing

NASA Astrophysics Data System (ADS)

Gotow, Takahiro; Fujikawa, Sachie; Fujishiro, Hiroki I.; Ogura, Mutsuo; Chang, Wen Hsin; Yasuda, Tetsuji; Maeda, Tatsuro

2017-10-01

A clean and flat GaSb surface without native oxides has been attained by H2 plasma cleaning and subsequent in-situ N2 plasma nitridation process at 300 oC. The mechanisms of thermal desorption behavior of native oxides on GaSb have been studied by thermal desorption spectroscopy (TDS) analysis. The suitable heat treatment process window for preparing a clean GaSb surface is given. Auger electron spectroscopy (AES) analysis indicates that native oxides were completely removed on the GaSb surface after H2 plasma exposure and the pure nitridation of the clean GaSb surface was obtained at a relatively low temperature of 300 °C. This pure nitridation of GaSb have a possibility to be used as a passivation layer for high quality GaSb MOS devices.

The structure directing effect of organic cations onto the crystal structures of layered thioantimonates(III): Solvothermal synthesis and crystal structures of five new compounds containing the 2∞[Sb 8S 13] 2- anion

NASA Astrophysics Data System (ADS)

Puls, Angela; Näther, Christian; Kiebach, Ragnar; Bensch, Wolfgang

2006-09-01

The five new thioantimonates(III) ( iprH) 2[Sb 8S 13] ( I), (1,2-dapH) 2[Sb 8S 13] ( II), (1,3-dapH 2)[Sb 8S 13] ( III), (dienH 2)[Sb 8S 13]ṡ1.5H 2O ( IV), and (C 6H 9N 2)[Sb 8S 13]ṡ2.5H 2O ( V) were synthesised under solvothermal conditions ( ipr = iso-propylamine; 1,2-dap = 1,2-diaminopropane; 1,3-dap = 1,3-diaminopropane; dien = diethylentriamine; C 6H 9N 2 = 3-(aminoethyl)-pyridine). The structures of compounds I and II are topological very similar and a central motif is a Sb 10S 10 ring. On both sides of this ring Sb 5S 5 rings are condensed. These rings are connected via Sb 4S 4 rings leading to the sequence Sb 10S 10-Sb 5S 5-Sb 4S 4-Sb 5S 5-Sb 10Sb 10 in the [010] direction. Further interconnection into the two-dimensional [Sb 8S 13] 2- anion produces a large central Sb 18S 18 ring with dimensions of 11ṡ11 Å in both compounds. The two atoms thick layers are linear and stacked along the a axis generating large channels running along [010]. The layered anion of compound III is constructed by interconnection of the SbS 3 and SbS 4 units yielding Sb 19S 19, Sb 14S 14, Sb 13S 13, and Sb 8S 8 rings. The linear layers are two atoms thick and are stacked perpendicular to [001] to form channels running along the same direction. The last two compounds IV and V show a similar network topology. The layered anion is constructed by SbS 3 trigonal pyramids and SbS 4 units. The layer contains a Sb 12S 12 rings as the main structural motif. The corrugated layers extending in the (100) plane are two atoms thick and are stacked in a manner that large tunnels run along [100]. The total potential solvent areas are large and range from 20.7% for III to 35% for II.

Superconductivity in BaPtSb with an Ordered Honeycomb Network

NASA Astrophysics Data System (ADS)

Kudo, Kazutaka; Saito, Yuki; Takeuchi, Takaaki; Ayukawa, Shin-ya; Kawamata, Takayuki; Nakamura, Shinichiro; Koike, Yoji; Nohara, Minoru

2018-06-01

Superconductivity in BaPtSb with the SrPtSb-type structure (space group P\\bar{6}m2, D3h1, No. 187) is reported. The structure consists of a PtSb ordered honeycomb network that stacks along the c-axis so that spatial inversion symmetry is broken globally. Electrical resistivity and specific-heat measurements revealed that the compound exhibited superconductivity at 1.64 K. The noncentrosymmetric structure and the strong spin-orbit coupling of Pt and Sb make BaPtSb an attractive compound for studying the exotic superconductivity predicted for a honeycomb network.

Effect of the C3a-receptor antagonist SB 290157 on anti-OVA polyclonal antibody-induced arthritis.

PubMed

Hutamekalin, Pilaiwanwadee; Takeda, Kohei; Tani, Mitsuhiro; Tsuga, Yuko; Ogawa, Naoki; Mizutani, Nobuaki; Yoshino, Shin

2010-01-01

It was investigated whether the C3a-receptor antagonist (C3aRA) SB 290157 was involved in the suppression of anti-OVA pAb-induced arthritis because it is well known that anaphylatoxin C3a plays a crucial role in the development of an effective inflammatory response during complement activation. Anti-OVA pAb-induced arthritis was induced in DBA/1J mice by administration of anti-OVA pAb 0.5 h prior to intra-articular (i.a.) injection of OVA (0 h). Two peaks of joint swelling were observed at 0.5 and 3 h. The role of C3aRA in arthritis was investigated by injection of SB 290157 at concentrations of 10 and 30 mg/kg at 0 and 2 h. The antagonist was able to reduce joint swelling only at 3 h, and about 50% inhibition of joint swelling was observed with the concentration of 30 mg/kg. The C3 level was significantly decreased at 3 h compared with naïve mice showing complement consumption. Furthermore, the C3 activation was observed and increased corresponding to the graded concentration of anti-OVA pAb. The results also revealed that the C3aRA was able to reduce the expression of IL-1beta in synovial tissue. Taken together, the results suggested that C3aRA may be effective in the inhibition of arthritis.

Chemical route for formation of intermetallic Zn 4Sb 3 phase

NASA Astrophysics Data System (ADS)

Denoix, A.; Solaiappan, A.; Ayral, R. M.; Rouessac, F.; Tedenac, J. C.

2010-05-01

Synthesis of intermetallic zinc antimonide phases via low temperature solution route was investigated. Trial experiments were carried out under inert atmosphere at 70 °C using metallic Zn, SbCl 3 and NaBH 4 as reactants and tetrahydrofuran (THF), dimethylsulfoxide (DMSO) as organic media. Powder X-ray analysis confirmed the nucleation and growth of ZnSb phases in presence of excess Zn. SEM analysis revealed the existence of core-shell structure comprising of Zn core and Sb shell. Such particles get transformed into Zn 4Sb 3 crystalline phases upon thermal treatment at 300 °C/6 h in a silica tube closed under high secondary vacuum.

Multilayer SnSb4-SbSe Thin Films for Phase Change Materials Possessing Ultrafast Phase Change Speed and Enhanced Stability.

PubMed

Liu, Ruirui; Zhou, Xiao; Zhai, Jiwei; Song, Jun; Wu, Pengzhi; Lai, Tianshu; Song, Sannian; Song, Zhitang

2017-08-16

A multilayer thin film, comprising two different phase change material (PCM) components alternatively deposited, provides an effective means to tune and leverage good properties of its components, promising a new route toward high-performance PCMs. The present study systematically investigated the SnSb 4 -SbSe multilayer thin film as a potential PCM, combining experiments and first-principles calculations, and demonstrated that these multilayer thin films exhibit good electrical resistivity, robust thermal stability, and superior phase change speed. In particular, the potential operating temperature for 10 years is shown to be 122.0 °C and the phase change speed reaches 5 ns in the device test. The good thermal stability of the multilayer thin film is shown to come from the formation of the Sb 2 Se 3 phase, whereas the fast phase change speed can be attributed to the formation of vacancies and a SbSe metastable phase. It is also demonstrated that the SbSe metastable phase contributes to further enhancing the electrical resistivity of the crystalline state and the thermal stability of the amorphous state, being vital to determining the properties of the multilayer SnSb 4 -SbSe thin film.

Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film

NASA Astrophysics Data System (ADS)

Li, Jia-Ning; Gong, Shui-Li; Sun, Mei; Shan, Fei-Hu; Wang, Xi-Chang; Jiang, Shuai

2013-11-01

A nano/amorphous-composite film was fabricated by laser cladding (LC) of the Co-Ti-B4C-Sb mixed powders on a TA15 alloy. Such film mainly consisted of Ti-Al, Co-Ti, Co-Sb intermetallics, TiC, TiB2, TiB, and the amorphous phases. Experimental results indicated that the crystal systems of TiB2 (hexagonal)/TiC (cubic) and Sb (rhombohedral) played important role on the formation of such film. Due to the mismatch of these crystals systems and mutual immiscibility of the metallic components, Sb was not incorporated in TiB2/TiC, but formed separate nuclei during the film growth. Thus, the growth of TiB2/TiC was stopped by the Sb nucleus in such LC molten pool, so as to form the nanoscale particles.

In-situ crystallization of GeTe\\GaSb phase change memory stacked films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velea, A., E-mail: alin.velea@psi.ch; National Institute of Materials Physics, RO-077125 Magurele, Ilfov; Borca, C. N.

2014-12-21

Single and double layer phase change memory structures based on GeTe and GaSb thin films were deposited by pulsed laser deposition (PLD). Their crystallization behavior was studied using in-situ synchrotron techniques. Electrical resistance vs. temperature investigations, using the four points probe method, showed transition temperatures of 138 °C and 198 °C for GeTe and GaSb single films, respectively. It was found that after GeTe crystallization in the stacked films, Ga atoms from the GaSb layer diffused in the vacancies of the GeTe crystalline structure. Therefore, the crystallization temperature of the Sb-rich GaSb layer is decreased by more than 30 °C. Furthermore, at 210 °C,more » the antimony excess from GaSb films crystallizes as a secondary phase. At higher annealing temperatures, the crystalline Sb phase increased on the expense of GaSb crystalline phase which was reduced. Extended X-ray absorption fine structure (EXAFS) measurements at the Ga and Ge K-edges revealed changes in their local atomic environments as a function of the annealing temperature. Simulations unveil a tetrahedral configuration in the amorphous state and octahedral configuration in the crystalline state for Ge atoms, while Ga is four-fold coordinated in both as-deposited and annealed samples.« less

The Co-Sb-Ga System: Isoplethal Section and Thermodynamic Modeling

NASA Astrophysics Data System (ADS)

Gierlotka, Wojciech; Chen, Sinn-wen; Chen, Wei-an; Chang, Jui-shen; Snyder, G. Jeffrey; Tang, Yinglu

2015-04-01

The Co-Sb-Ga ternary system is an important thermoelectric material system, and its phase equilibria are in need of further understanding. The CoSb3-GaSb isoplethal section is experimentally determined in this study. Phase equilibria of the ternary Co-Sb-Ga system are assessed, and the system's thermodynamic models are developed. In addition to the terminal phases and liquid phase, there are six binary intermediate phases and a ternary Co3Sb2Ga4 phase. The Ga solution in the CoSb3 compound is described by a dual-site occupation (GaVF) x Co4Sb12- x/2(GaSb) x/2 model. Phase diagrams are calculated using the developed thermodynamic models, and a reaction scheme is proposed based on the calculation results. The calculated results are in good agreement with the experimentally determined phase diagrams, including the CoSb3-GaSb isoplethal section, the liquidus projection, and an isothermal section at 923 K (650 °C). The dual-site occupation (GaVF) x Co4Sb12- x/2(GaSb) x/2 model gives good descriptions of both phase equilibria and thermoelectric properties of the CoSb3 phase with Ga doping.

Linear and nonlinear optical properties of Sb-doped GeSe2 thin films

NASA Astrophysics Data System (ADS)

Zhang, Zhen-Ying; Chen, Fen; Lu, Shun-Bin; Wang, Yong-Hui; Shen, Xiang; Dai, Shi-Xun; Nie, Qiu-Hua

2015-06-01

Sb-doped GeSe2 chalcogenide thin films are prepared by the magnetron co-sputtering method. The linear optical properties of as-deposited films are derived by analyzing transmission spectra. The refractive index rises and the optical band gap decreases from 2.08 eV to 1.41 eV with increasing the Sb content. X-ray photoelectron spectra further confirm the formation of a covalent Sb-Se bond. The third-order nonlinear optical properties of thin films are investigated under femtosecond laser excitation at 800 nm. The results show that the third-order nonlinear optical properties are enhanced with increasing the concentration of Sb. The nonlinear refraction indices of these thin films are measured to be on the order of 10-18 m2/W with a positive sign and the nonlinear absorption coefficients are obtained to be on the order of 10-10 m/W. These excellent properties indicate that Sb-doped Ge-Se films have a good prospect in the applications of nonlinear optical devices. Project supported by the National Key Basic Research Program of China (Grant No. 2012CB722703), the National Natural Science Foundation of China (Grant No. 61377061), the Young Leaders of Academic Climbing Project of the Education Department of Zhejiang Province, China (Grant No. pd2013092), the Program for Innovative Research Team of Ningbo City, China (Grant No. 2009B217), and the K. C. Wong Magna Fund in Ningbo University, China.

Thermal stability of active/inactive nanocomposite anodes based on Cu2Sb in lithium-ion batteries

NASA Astrophysics Data System (ADS)

Allcorn, Eric; Kim, Sang-Ok; Manthiram, Arumugam

2015-12-01

Various active/inactive nanocomposites of Cu2Sb-Al2O3@C, Cu2Sb-TiC, and Cu2Sb-TiC@C have been synthesized by high energy mechanical milling and investigated by differential scanning calorimetry (DSC) to determine the lithiated phase stability and heat generation arising from these electrodes. The milling process reduces the Li3Sb phase stability, relative to the un-milled samples, to below ∼200 °C. However, the incorporation of the reinforcing, inactive phases Al2O3, TiC, and carbon black offer a slight improvement. DSC curves also show that the low-temperature heat generation in the SEI-layer reaction range is not noticeably altered by either the milling process or the addition of the inactive phases. A strong exothermic peak is observed at ∼200 °C for the 0% state of charge electrodes of Cu2Sb-Al2O3@C and Cu2Sb-TiC@C that was caused by the incorporation of carbon black into the composite. This peak was not present in the electrodes of milled Cu2Sb or Cu2Sb-TiC, suggesting that efforts to extend the cycle life of alloy anodes should avoid carbon black due to its destabilizing effects on delithiated electrodes. Fourier Transform infrared spectroscopy analysis indicates that the reaction arising from the incorporation of carbon black is tied to a low-temperature breakdown of the lithium salt LiPF6.

Growth and characterization of chalcostibite CuSbSe2 thin films for photovoltaic application

NASA Astrophysics Data System (ADS)

Tiwari, Kunal J.; Vinod, Vijay; Subrahmanyam, A.; Malar, P.

2017-10-01

Bulk copper antimony selenide was synthesized using mechanical alloying from the elemental precursors. Phase formation in milled powders was studied using x-ray diffraction (XRD) and Raman spectroscopy studies. The synthesized bulk source after cold compaction was used as source material for thin film deposition by e-beam evaporation. Thin film deposition was carried out at various e-beam current values (Ib ∼30, 40 and 50 mA) and at a substrate temperature of 200 °C. Near stoichiometric CuSbSe2 thin films were obtained for Ib values closer to 50 mA and post annealing at a temperature of 380 °C for 1 h. Thin films deposited using above conditions were found to exhibit an absorption coefficient (α) values of >105 cm-1 and a band gap value ∼1.18 eV that is closer to the reported band gap for CuSbSe2 compound.

Electrical and optical characterization of n-InAsSb/n-GaSb heterojunctions

NASA Astrophysics Data System (ADS)

Lackner, D.; Martine, M.; Cherng, Y. T.; Steger, M.; Walukiewicz, W.; Thewalt, M. L. W.; Mooney, P. M.; Watkins, S. P.

2010-01-01

We report the electrical properties of n-InAsSb/n-GaSb heterojunctions as a function of the GaSb doping concentration. Because of the staggered type II band alignment, strong electron accumulation occurs on the InAsSb side. For low GaSb doping, depletion occurs on the GaSb side resulting in a Schottky-like junction as previously reported. As the GaSb doping increases, the built-in voltage as well as depletion width decreases as shown using self-consistent simulations. For GaSb doping levels above 5×1017 cm-3, the junction loses its rectifying properties due to tunneling. Under zero and reverse bias voltage, the photoresponse of these diodes is solely due to the photovoltaic effect in the GaSb depletion region. For forward bias voltages >400 mV, we also observed a photoconductive response from the InAsSb layer. The proposed physical mechanism is quite different from the one suggested in a recent paper.

The Role of Anionogenic Elements (As, Sb, Mo, Se, S, P, N, Cl, F, C) In The Formation of Technogenic Geochemical Anomalies

NASA Astrophysics Data System (ADS)

Abrosimova, Natalya; Bortnikova, Svetlana

2017-12-01

The study was conducted on the example of sulphide-containing mine tailings with a varying amount of sulphide and arsenide minerals, from three distinct tailings dumps situated in Russia: Karabash Mine Site, South Ural; Komsomolsk tailings impoundment, Kemerovo region; Khovu-Aksy mine site, Tuva Republic. The aim of the study was to compare the mobility of anionogenic elements (As, Sb, Mo, Se, S, P, N, Cl, F, C) and their role in migration, precipitation, and concentration of metals during the water-tailings interaction depending on the physicochemical parameters (pH, Eh) of the medium and the mineral composition of the waste material. Using slightly acidic leaching experiments the quantitative estimation of mobile forms of elements is given. Based on the compositions of the obtained water leaching solutions, aqueous speciation of chemical elements and saturation index of key minerals in the experimental solutions were calculated. The results of calculating forms of chemical elements made it possible to construct series of mobility of metals and metalloids in solutions with different physicochemical parameters. In the alkaline conditions, Sb>As>Cd>Cu>Zn>Fe>Pb, when the medium is acidified, the series changes, As>Cd>Cu>Zn>Pb>Sb>Fe in weakly alkaline conditions, Sb>Mn>As>Zn>Fe however, when the medium is acidified, the series changes to Cd>Mn>Pb>Cu>Zn>Sb>Ni>Fe>As under acidic conditions Cd>Cu>Zn>Pb>Mn>Fe>Se>Mo>Sb>As>Ni. The mineral composition of the tailings was investigated, which will allow to determine the sources of toxic elements and to understand the processes of secondary mineral formation in technogenic objects. Arsenopyrite and pyrite predominate in the heavy fraction of the Komsomolsk tailings impoundment, arsenopyrite grains are often corroded, Sb contained in Sb oxide and Sb sulfide. The pyrite and barite are determined in the solid matter of the Karabash Mine Site and chalcopyrite, sphalerite, tennantite Cu3AsS3, and tetrahedrite (Cu,Fe)12Sb4S13 are

Microbiological reduction of Sb(V) in anoxic freshwater sediments

USGS Publications Warehouse

Oremland, Ronald S.; Kulp, Thomas R.; Miller, Laurence G.; Braiotta, Franco; Webb, Samuel M.; Kocar, Benjamin D; Blum, Jodi S.

2014-01-01

Microbiological reduction of millimolar concentrations of Sb(V) to Sb(III) was observed in anoxic sediments from two freshwater settings: (1) a Sb- and As-contaminated mine site (Stibnite Mine) in central Idaho and 2) an uncontaminated suburban lake (Searsville Lake) in the San Francisco Bay Area. Rates of Sb(V) reduction in anoxic sediment microcosms and enrichment cultures were enhanced by amendment with lactate or acetate as electron donors but not by H2, and no reduction occurred in sterilized controls. Addition of 2-14C-acetate to Stibnite Mine microcosms resulted in the production of 14CO2 coupled to Sb(V) reduction, suggesting that this process proceeds by a dissimilatory respiratory pathway in those sediments. Antimony(V) reduction in Searsville Lake sediments was not coupled to acetate mineralization and may be associated with Sb-resistance. The microcosms and enrichment cultures also reduced sulfate, and the precipitation of insoluble Sb(III)-sulfide complexes was a major sink for reduced Sb. The reduction of Sb(V) by Stibnite Mine sediments was inhibited by As(V), suggesting that As(V) is a preferred electron acceptor for the indigenous community. These findings indicate a novel pathway for anaerobic microbiological respiration and suggest that communities capable of reducing high concentrations of Sb(V) commonly occur naturally in the environment.

Bi-induced band gap reduction in epitaxial InSbBi alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rajpalke, M. K.; Linhart, W. M.; Yu, K. M.

2014-11-24

The properties of molecular beam epitaxy-grown InSb 1-x Bi x alloys are investigated. Rutherford backscattering spectrometry shows that the Bi content increases from 0.6% for growth at 350 °C to 2.4% at 200 °C. X-ray diffraction indicates Bi-induced lattice dilation and suggests a zinc-blende InBi lattice parameter of 6.626 Å. Scanning electron microscopy reveals surface InSbBi nanostructures on the InSbBi films for the lowest growth temperatures, Bi droplets at intermediate temperatures, and smooth surfaces for the highest temperature. The room temperature optical absorption edge was found to change from 172 meV (7.2 μm) for InSb to ~88 meV (14.1 μm)more » for InSb 0.976Bi 0.024, a reduction of ~35 meV/%Bi.« less

Determination of lansoprazole in human plasma by rapid resolution liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study on Chinese volunteers.

PubMed

Wu, Guo-Lan; Zhou, Hui-Li; Shentu, Jian-Zhong; He, Qiao-Jun; Yang, Bo

2008-12-15

A simple, sensitive and rapid LC/MS/MS method was developed for the quantification of lansoprazole in human plasma. After a simple sample preparation procedure by one-step protein precipitation with acetonitrile, lansoprazole and the internal standard bicalutamide were chromatographed on a Zorbax SB-C(18) (3.0 mm x 150 mm, 3.5 microm, Agilent) column with the mobile phase consisted of methanol-water (70:30, v/v, containing 5 mM ammonium formate, pH was adjusted to 7.85 by 1% ammonia solution). Detection was performed on a triple quadrupole tandem mass spectrometry by multiple reaction monitoring (MRM) mode via negative eletrospray ionization source (ESI(-)). The lower limit of quantification was 5.5 ng/mL, and the assay exhibited a linear range of 5.5-2200.0 ng/mL. The validated method was successfully applied to investigate the bioequivalence between two kinds of preparation (test vs. reference product) in twenty-eight healthy male Chinese volunteers.

Simultaneous determination of flavonoids, isochlorogenic acids and triterpenoids in Ilex hainanensis Using high performance liquid chromatography coupled with diode array and evaporative light scattering detection.

PubMed

Peng, Bo; Qiao, Chun-Feng; Zhao, Jing; Huang, Wei-Hua; Hu, De-Jun; Liu, Hua-Gang; Li, Shao-Ping

2013-03-04

A high performance liquid chromatography coupled with diode array and evaporative light scattering detection (HPLC-DAD-ELSD) method for simultaneous determination of eight major bioactive compounds including two flavonoids (rutin and eriodictyol-7-O-β-D-glucopyranoside), two isochlorogenic acids (isochlorogenic acid A and isochlorogenic acid C) and four triterpenoids (ilexhainanoside D, ilexsaponin A1, ilexgenin A and ursolic acid) in Ilex hainanensis has been developed for the first time. The 283 nm wavelength was chosen for determination of two flavonoids and two isochlorogenic acids. ELSD was applied to determine four triterpenoids. The analysis was performed on an Agilent Zorbax SB-C18 column (250 × 4.6 mm i.d., 5 µm) with gradient elution of 0.2% formic acid in water and acetonitrile. The method was validated for linearity, limit of detection, limit of quantification, precision, repeatability and accuracy. The proposed method has been successfully applied for simultaneous quantification of the analytes in four samples of Ilex hainanensis, which is helpful for quality control of this plant.

Combination of COFRADIC and high temperature-extended column length conventional liquid chromatography: a very efficient way to tackle complex protein samples, such as serum.

PubMed

Sandra, Koen; Verleysen, Katleen; Labeur, Christine; Vanneste, Lies; D'Hondt, Filip; Thomas, Grégoire; Kas, Koen; Gevaert, Kris; Vandekerckhove, Joël; Sandra, Pat

2007-03-01

The previously reported COmbined FRActional DIagonal Chromatography (COFRA-DIC) methodology, in which a subset of peptides representative for their parent proteins are sorted, is particularly powerful for whole proteome analysis. This peptide-centric technology is built around diagonal chromatography, where peptide separations are crucial. This paper presents high efficiency peptide separations, in which four 250 x 2.1 mm, 5 microm Zorbax 300SB-C18 columns (total length 1 m) were coupled at operating temperatures of 60'C using a dedicated LC oven and conventional LC equipment. The high efficiency separations were combined with the COFRADIC procedure. This extremely powerful combination resulted, for the analysis of serum, in an increase in the uniquely identified peptide sequences by a factor of 2.6, compared to the COFRADIC procedure on a 25 cm column. This is a reflection of the increased peak capacity obtained on the 1 m column, which was calculated to be a factor 2.7 higher than on the 25 cm column. Besides more efficient sorting, less ion suppression was noticed.

Cinnamic acid 4-hydroxylase of sorghum [Sorghum biocolor (L.) Moench] gene SbC4H1 restricts lignin synthesis in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Cinnamic acid 4-hydroxylase (C4H) is the first hydroxylase enzyme of the phenylpropanoid pathway, and its content and activity affects the lignin synthesis. In this study, we isolated a C4H gene SbC4H1 from the suppression subtractive hybridization library of brown midrib (bmr) mutants of Sorghum b...

Low intrinsic c-axis thermal conductivity in PVD grown epitaxial Sb2Te3 films

NASA Astrophysics Data System (ADS)

Rieger, F.; Kaiser, K.; Bendt, G.; Roddatis, V.; Thiessen, P.; Schulz, S.; Jooss, C.

2018-05-01

Accurate determination and comprehensive understanding of the intrinsic c-axis thermal conductivity κc of thermoelectric layered Sb2Te3 is of high importance for the development of strategies to optimize the figure of merit in thin film devices via heterostructures and defect engineering. We present here high precision measurements of κc of epitaxial Sb2Te3 thin films on Al2O3 substrates grown by physical vapor deposition in the temperature range of 100 K to 300 K. The Kapitza resistances of the involved interfaces have been determined and subtracted from the film data, allowing access to the intrinsic thermal conductivity of single crystalline Sb2Te3. At room temperature, we obtain κc = 1.9 W/m K, being much smaller than the in-plane thermal conductivity of κa b = 5 W/m K and even lower than the thermal conductivity of nano crystalline films of κnc ≈ 2.0-2.6 W/m K published by Park et al. [Nanoscale Res. Lett. 9, 96 (2014)]. High crystallinity and very low defect concentration of the films were confirmed by x-ray diffraction and high resolution transmission electron microscopy. Our data reveal that the phonon mean free path lm f p(" separators="|T ) is not limited by defect scattering and is of intrinsic nature, i.e., due to phonon-phonon scattering similar to other soft van der Waals type bonded layered systems.

Magnetic and Electrical Transport Properties of Dirac Compound BaMnSb2*

NASA Astrophysics Data System (ADS)

Huang, Silu; Kim, Jisun; Shelton, William. A.; Plummer, Ward; Jin, Rongying

BaMnSb2 is a layered compound containing Sb square nets that is theoretically predicted to host Dirac fermions. We have carried out experimental investigations on electrical transport and magnetic properties of BaMnSb2 single crystals. Both in-plane (ρab) and c-axis (ρc) resistivities show metallic behavior with a small bump in ρc located near 40 K, while there is large anisotropy ρc / ρab ( 100 at 300 K) that increases with decreasing temperature to 1500 at 2 K. Interestingly, Shubnikov-de Hass (SdH) oscillations are observed for both ρab and ρc over a wide temperature and magnetic field range. Quantitative analysis indicates that large amplitude SdH oscillations result from nearly massless Dirac Fermions. Furthermore, our magnetic measurements indicate an A-type antiferromagnetic magnetic ordering below 286 K where ferromagnetic ordering is observed in the ab plane with antiferromagnetic coupling along the c direction. These results indicate that BaMnSb2 is a 2D magnetic Dirac material. This work is supported by NSF through Grant Number DMR-1504226.

Growth mechanisms of GaSb heteroepitaxial films on Si with an AlSb buffer layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vajargah, S. Hosseini; Botton, G. A.; Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1

2013-09-21

The initial growth stages of GaSb epilayers on Si substrates and the role of the AlSb buffer layer were studied by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Heteroepitaxy of GaSb and AlSb on Si both occur by Volmer-Weber (i.e., island mode) growth. However, the AlSb and GaSb islands have distinctly different characteristics as revealed through an atomic-resolution structural study using Z-contrast of HAADF-STEM imaging. While GaSb islands are sparse and three dimensional, AlSb islands are numerous and flattened. The introduction of 3D island-forming AlSb buffer layer facilitates the nucleation of GaSb islands. The AlSb islands-assisted nucleation of GaSbmore » islands results in the formation of drastically higher quality planar film at a significantly smaller thickness of films. The interface of the AlSb and GaSb epilayers with the Si substrate was further investigated with energy dispersive X-ray spectrometry to elucidate the key role of the AlSb buffer layer in the growth of GaSb epilayers on Si substrates.« less

Density functional simulations of Sb-rich GeSbTe phase change alloys.

PubMed

Gabardi, S; Caravati, S; Bernasconi, M; Parrinello, M

2012-09-26

We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge(1)Sb(1)Te(1) and Ge(2)Sb(4)Te(5). Comparison with previous results on the most studied Ge(2)Sb(2)Te(5) allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm(-1) are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge(2)Sb(2)Te(5). All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

Density functional simulations of Sb-rich GeSbTe phase change alloys

NASA Astrophysics Data System (ADS)

Gabardi, S.; Caravati, S.; Bernasconi, M.; Parrinello, M.

2012-09-01

We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge1Sb1Te1 and Ge2Sb4Te5. Comparison with previous results on the most studied Ge2Sb2Te5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm-1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge2Sb2Te5. All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

MOVPE of GaSb/InGaAsSb Multilayers and Fabrication of Dual Band Photodetectors

NASA Technical Reports Server (NTRS)

Xiao, Ye-Gao; Bhat, Ishwara; Refaat, Tamer F.; Abedin, M. Nurul; Shao, Qing-Hui

2005-01-01

Metalorganic vapor phase epitaxy (MOVPE) of GaSb/InGaAsSb multilayer thin films and fabrication of bias-selectable dual band photodetectors are reported. For the dual band photodetectors the short wavelength detector, or the upper p- GaSb/n-GaSb junction photodiode, is placed optically ahead of the long wavelength one, or the lower photodiode. The latter is based on latticed-matched In0.13Ga0.87As0.11Sb0.89 with bandgap near 0.6 eV. Specifically, high quality multilayer thin films are grown sequentially from top to bottom as p+-GaSb/p-GaSb/n-GaSb/n-InGaAsSb/p-InGaAsSb/p-GaSb on undoped p-type GaSb substrate, and as n-GaSb/p-GaSb/p-InGaAsSb/n-InGaAsSb/n-GaSb on Te-doped n-type GaSb substrate respectively. The multilayer thin films are characterized by optical microscope, atomic force microscope (AFM), electron microprobe analyses etc. The photodiode mesa steps are patterned by photolithography with wet chemical etching and the front metallization is carried out by e-beam evaporation with Pd/Ge/Au/Ti/Au to give ohmic contact on both n- and p-type Sb based layer surfaces. Dark I-V measurements show typical diode behavior for both the upper and lower photodiodes. The photoresponsivity measurements indicate that both the upper and lower photodiodes can sense the infrared illumination corresponding to their cutoff wavelengths respectively, comparable with the simulation results. More work is underway to bring the long wavelength band to the medium infrared wavelength region near 4 micrometers.

Effect of Se substitution on the phase change properties of Ge2Sb2Te5

NASA Astrophysics Data System (ADS)

Shekhawat, Roopali; Rangappa, Ramanna; Gopal, E. S. R.; Ramesh, K.

2018-05-01

Ge2Sb2Te5 popularly known as GST is being explored for non-volatile phase change random access memory(PCRAM) applications. Under high electric field, thin films of amorphous GST undergo a phase change from amorphous to crystalline with a high contrast in electrical resistivity (about 103). The phase change is between amorphous and metastable NaCl structure occurs at about 150°C and not to the stable hexagonal phase which occurs at a high temperature (> 250 °C). In GST, about 50 % of Te substituted by Se (Ge2Sb2Te2.5Se2.5) is found to increase the contrast in electrical resistivity by 7 orders of magnitude (about 4 orders of magnitude higher than GST). The phase transition in Se added GST also found to be between amorphous and the stable hexagonal structure. The threshold voltage at which the Ge2Sb2Te2.5Se2.5 switches to the high conducting state increases to 9V as compared to 2V in GST. Interestingly, the threshold current decrease to 1mA as compared to 1.8mA in GST indicating the Se substitution reduces the power needed for switching between the low and high conducting states. The reduction in power needed for phase change, high contrast in electrical resistivity with high thermal stability makes Ge2Sb2Te2.5Se2.5 as a better candidate for PCRAM.

AlInAsSb for GaSb-based multi-junction solar cells

NASA Astrophysics Data System (ADS)

Tournet, J.; Rouillard, Y.; Tournié, E.

2018-02-01

Bandgap engineering, by means of alloying or inserting nanostructures, is the bedrock of high efficiency photovoltaics. III-V quaternary alloys in particular enable bandgap tailoring of a multi-junction subcell while conserving a single lattice parameter. Among the possible candidates, AlInAsSb could in theory reach the widest range of bandgap energies while being lattice-matched to InP or GaSb. Although these material systems are still emerging photovoltaic segments, they do offer advantages for multi-junction design. GaSbbased structures in particular can make use of highly efficient GaSb/InAs tunnel junctions to connect the subcells. There has been only little information concerning GaSb-lattice matched AlInAsSb in the literature. The alloy's miscibility gap can be circumvented by the use of non-equilibrium techniques. Nevertheless, appropriate growth conditions remain to be found in order to produce a stable alloy. Furthermore, the abnormally low bandgap energies reported for the material need to be confirmed and interpreted with a multi-junction perspective. In this work, we propose a tandem structure made of an AlInAsSb top cell and a GaSb bottom cell. An epitaxy study of the AlInAsSb alloy lattice-matched to GaSb was first performed. The subcells were then grown and processed. The GaSb subcell yielded an efficiency of 5.9% under 1 sun and the tandem cell is under optimization. Preliminary results are presented in this document.

Investigation of regime switching from mode locking to Q-switching in a 2 µm InGaSb/AlGaAsSb quantum well laser.

PubMed

Li, Xiang; Wang, Hong; Qiao, Zhongliang; Guo, Xin; Wang, Wanjun; Ng, Geok Ing; Zhang, Yu; Xu, Yingqiang; Niu, Zhichuan; Tong, Cunzhu; Liu, Chongyang

2018-04-02

A two-section InGaSb/AlGaAsSb single quantum well (SQW) laser emitting at 2 μm is presented. By varying the absorber bias voltage with a fixed gain current at 130 mA, passive mode locking at ~18.40 GHz, Q-switched mode locking, and passive Q-switching are observed in this laser. In the Q-switched mode locking regimes, the Q-switched RF signal and mode locked RF signal coexist, and the Q-switched lasing and mode-locked lasing happen at different wavelengths. This is the first observation of these three pulsed working regimes in a GaSb-based diode laser. An analysis of the regime switching mechanism is given based on the interplay between the gain saturation and the saturable absorption.

High performance Sb2S3/carbon composite with tailored artificial interface as an anode material for sodium ion batteries

NASA Astrophysics Data System (ADS)

Choi, Jeong-Hee; Ha, Chung-Wan; Choi, Hae-Young; Shin, Heon-Cheol; Lee, Sang-Min

2017-11-01

The electrochemical comparison between Sb2S3 and its composite with carbon (Sb2S3/C) involved by sodium ion carrier are explained by enhanced kinetics, particularly with respect to improved interfacial conductivity by surface modulation by carbon. Sb2S3 and Sb2S3/C are synthesized by a high energy mechanical milling process. The successful synthesis of these materials is confirmed with X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM). As an anode material for sodium ion batteries, Sb2S3 exhibits an initial sodiation/desodiation capacity of 1,021/523 mAh g-1 whereas the Sb2S3/C composite exhibits a higher reversible capacity (642 mAh g-1). Furthermore, the cycle performance and rate capability of the Sb2S3/C composite are estimated to be much better than those of Sb and Sb2S3. Electrochemical impedance spectroscopy analysis shows that the Sb2S3/C composite exhibited charge transfer resistance and surface film resistance much lower than Sb2S3. X-ray photoelectron spectroscopy analyses of both electrodes demonstrate that NaF layer on Sb2S3/C composite electrode leads to the better electrochemical performances. In order to clarify the electrochemical reaction mechanism, ex-situ XRD based on differential capacity plots and ex-situ HR-TEM analyses of the Sb2S3/C composite electrode are carried out and its reaction mechanism was established.

40 CFR 721.3025 - Fatty acids C12-18, C18 unsaturated, C12-18 alkyl esters (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., C12-18 alkyl esters (generic). 721.3025 Section 721.3025 Protection of Environment ENVIRONMENTAL... communication program. A significant new use of these substances is any manner or method of manufacture, import, or processing associated with any use of these substances without providing risk notification as...

The 5-HT₂C receptor agonist, lorcaserin, and the 5-HT₆ receptor antagonist, SB-742457, promote satiety; a microstructural analysis of feeding behaviour.

PubMed

Higgs, Suzanne; Cooper, Alison J; Barnes, Nicholas M

2016-02-01

Whilst the FDA-approved anorectic, lorcaserin and various 5-hydroxytryptamine (5-HT)6 receptor antagonists reduce feeding, a direct assessment of their impact upon feeding behaviour is less clear. We therefore examined the action of lorcaserin and the clinical-stage developmental candidate 5-HT6 receptor antagonist, SB-742457, upon microstructural analysis of licking behaviour. Such analysis provides a rich source of information about the mechanisms controlling food intake. The objective of the present study was to gain insight into the influence upon feeding behaviour of the 5-HT2C receptor agonist, lorcaserin and the developmental 5-HT6 receptor antagonist, SB-742457. The impact of lorcaserin and SB-742457 upon licking behaviour of non-deprived rats for a glucose solution was assessed using microstructural analysis. Lorcaserin (0.1-3.0 mg/kg) displayed a dose-dependent ability to reduce glucose consumption via reduction in the number of bouts of licking. A similar action was evident with SB-742457, but only at the lowest dose tested (3.0 mg/kg). The behavioural actions of both lorcaserin and SB-742457 demonstrate they directly promote satiety.

Two-band superlinear electroluminescence in GaSb based nanoheterostructures with AlSb/InAs{sub 1−x} Sb{sub x}/AlSb deep quantum well

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikhailova, M. P.; Ivanov, E. V.; Danilov, L. V.

2014-06-14

We report on superlinear electroluminescent structures based on AlSb/InAs{sub 1−x}Sb{sub x}/AlSb deep quantum wells grown by MOVPE on n-GaSb:Te substrates. Dependence of the electroluminescence (EL) spectra and optical power on the drive current in nanoheterostructures with AlSb/InAs{sub 1−x}Sb{sub x}/AlSb quantum well at 77–300 K temperature range was studied. Intensive two-band superlinear EL in the 0.5–0.8 eV photon energy range was observed. Optical power enhancement with the increasing drive current at room temperature is caused by the contribution of the additional electron-hole pairs due to the impact ionization by the electrons heated at the high energy difference between AlSb and the first electronmore » level E{sub e1} in the InAsSb QW. Study of the EL temperature dependence at 90–300 K range enabled us to define the role of the first and second heavy hole levels in the radiative recombination process. It was shown that with the temperature decrease, the relation between the energies of the valence band offset and the second heavy hole energy level changes due to the temperature transformation of the energy band diagram. That is the reason why the EL spectrum revealed radiative transitions from the first electron level E{sub e1} to the first hole level E{sub h1} in the whole temperature range (90–300 K), while the emission band related with the transitions to the second hole level occurred only at T > 200 K. Comparative examination of the nanostructures with high band offsets and different interface types (AlAs-like and InSb-like) reveals more intense EL and optical power enhancement at room temperature in the case of AlAs-like interface that could be explained by the better quality of the heterointerface and more efficient hole localization.« less

Sequential and simultaneous adsorption of Sb(III) and Sb(V) on ferrihydrite: Implications for oxidation and competition.

PubMed

Qi, Pengfei; Pichler, Thomas

2016-02-01

Antimony (Sb) is a naturally occurring element of growing environmental concern whose toxicity, adsorption behavior and other chemical properties are similar to that of arsenic (As). However, less is known about Sb compared to As. Individual and simultaneous adsorption experiments with Sb(III) and Sb(V) were conducted in batch mode with focus on the Sb speciation of the remaining liquid phase during individual Sb(III) adsorption experiments. The simultaneous adsorption and oxidation of Sb(III) was confirmed by the appearance of Sb(V) in the solution at varying Fe/Sb ratios (500, 100 and 8) and varying pH values (3.8, 7 and 9). This newly formed Sb(V) was subsequently removed from solution at a Fe/Sb ratio of 500 or at a pH of 3.8. However, more or less only Sb(V) was observed in the liquid phase at the end of the experiments at lower Fe/Sb ratios and higher pH, indicating that competition took place between the newly formed Sb(V) and Sb(III), and that Sb(III) outcompeted Sb(V). This was independently confirmed by simultaneous adsorption experiments of Sb(III) and Sb(V) in binary systems. Under such conditions, the presence of Sb(V) had no influence on the adsorption of Sb(III) while Sb(V) adsorption was significantly inhibited by Sb(III) over a wide pH range (4-10). Thus, in the presence of ferrihydrite and under redox conditions, which allow the presence of both Sb species, Sb(V) should be the dominant species in aquatic environments, since Sb(III) is adsorbed preferentially and at the same time oxidized to Sb(V). Copyright © 2015 Elsevier Ltd. All rights reserved.

ZnS-Sb2S3@C Core-Double Shell Polyhedron Structure Derived from Metal-Organic Framework as Anodes for High Performance Sodium Ion Batteries.

PubMed

Dong, Shihua; Li, Caixia; Ge, Xiaoli; Li, Zhaoqiang; Miao, Xianguang; Yin, Longwei

2017-06-27

Taking advantage of zeolitic imidazolate framework (ZIF-8), ZnS-Sb 2 S 3 @C core-double shell polyhedron structure is synthesized through a sulfurization reaction between Zn 2+ dissociated from ZIF-8 and S 2- from thioacetamide (TAA), and subsequently a metal cation exchange process between Zn 2+ and Sb 3+ , in which carbon layer is introduced from polymeric resorcinol-formaldehyde to prevent the collapse of the polyhedron. The polyhedron composite with a ZnS inner-core and Sb 2 S 3 /C double-shell as anode for sodium ion batteries (SIBs) shows us a significantly improved electrochemical performance with stable cycle stability, high Coulombic efficiency and specific capacity. Peculiarly, introducing a carbon shell not only acts as an important protective layer to form a rigid construction and accommodate the volume changes, but also improves the electronic conductivity to optimize the stable cycle performance and the excellent rate property. The architecture composed of ZnS inner core and a complex Sb 2 S 3 /C shell not only facilitates the facile electrolyte infiltration to reduce the Na-ion diffusion length to improve the electrochemical reaction kinetics, but also prevents the structure pulverization caused by Na-ion insertion/extraction. This approach to prepare metal sulfides based on MOFs can be further extended to design other nanostructured systems for high performance energy storage devices.

Investigation of directionally solidified InGaSb ternary alloys from Ga and Sb faces of GaSb(111) under prolonged microgravity at the International Space Station

PubMed Central

Nirmal Kumar, Velu; Arivanandhan, Mukannan; Rajesh, Govindasamy; Koyama, Tadanobu; Momose, Yoshimi; Sakata, Kaoruho; Ozawa, Tetsuo; Okano, Yasunori; Inatomi, Yuko; Hayakawa, Yasuhiro

2016-01-01

InGaSb ternary alloys were grown from GaSb (111)A and B faces (Ga and Sb faces) under microgravity conditions on board the International Space Station by a vertical gradient freezing method. The dissolution process of the Ga and Sb faces of GaSb and orientation-dependent growth properties of InGaSb were analysed. The dissolution of GaSb(111)B was greater than that of (111)A, which was found from the remaining undissolved seed and feed crystals. The higher dissolution of the Sb face was explained based on the number of atoms at that face, and its bonding with the next atomic layer. The growth interface shape was almost flat in both cases. The indium composition in both InGaSb samples was uniform in the radial direction and it gradually decreased along the growth direction because of segregation. The growth rate of InGaSb from GaSb (111)B was found to be higher than that of GaSb (111)A because of the higher dissolution of GaSb (111)B. PMID:28725736

Investigation of directionally solidified InGaSb ternary alloys from Ga and Sb faces of GaSb(111) under prolonged microgravity at the International Space Station.

PubMed

Nirmal Kumar, Velu; Arivanandhan, Mukannan; Rajesh, Govindasamy; Koyama, Tadanobu; Momose, Yoshimi; Sakata, Kaoruho; Ozawa, Tetsuo; Okano, Yasunori; Inatomi, Yuko; Hayakawa, Yasuhiro

2016-01-01

InGaSb ternary alloys were grown from GaSb (111)A and B faces (Ga and Sb faces) under microgravity conditions on board the International Space Station by a vertical gradient freezing method. The dissolution process of the Ga and Sb faces of GaSb and orientation-dependent growth properties of InGaSb were analysed. The dissolution of GaSb(111)B was greater than that of (111)A, which was found from the remaining undissolved seed and feed crystals. The higher dissolution of the Sb face was explained based on the number of atoms at that face, and its bonding with the next atomic layer. The growth interface shape was almost flat in both cases. The indium composition in both InGaSb samples was uniform in the radial direction and it gradually decreased along the growth direction because of segregation. The growth rate of InGaSb from GaSb (111)B was found to be higher than that of GaSb (111)A because of the higher dissolution of GaSb (111)B.

Synthesis and Optimization of Thermoelectric Properties of Zn(x)Sb3

NASA Technical Reports Server (NTRS)

Doan-Nguyen, Vicky V.

2005-01-01

High-performance thermoelectric materials are studied to investigate their abilities to optimize electrical and minimize thermal conductivities. A stoichiometric range of p-type zinc antimonide compounds was synthesized to analyze the trends in their thermoelectric properties. Zn(x)Sb3 (x=3.80, 3.85, 3.90, 3.95, 4.00, 4.05, 4.10) was reacted at 750 C and annealed at 300 C for 24 hours at each temperature. Electronic transport properties such as Seebeck and Hall Effect were measured to analyze possible trends in the set of compositions. SEM, EDS, and XRD were used to quantify both ingots and hot-pressed samples to confirm that they were single-phase and of the expected stoichiometries. Recent SEM data indicated that Zn(3.90)Sb3 and Zn(4.00)Sb3 samples were actually Zn3Sb2. In hopes of further improving the figure-of-merit (ZT) of the binary system, V, Cr, Mn, Fe, Co, In, and Sn were used to dope (Zn(0.95)M(0.05))(3.95)Sb3.

Enhanced Hole Mobility and Density in GaSb Quantum Wells

DTIC Science & Technology

2013-01-01

Keywords: Molecular beam epitaxy Quantum wells Semiconducting III–V materials Field-effect transistors GaSb a b s t r a c t Modulation-doped quantum wells...QWs) of GaSb clad by AlAsSb were grown by molecular beam epitaxy on InP substrates. By virtue of quantum confinement and compressive strain of the...heterostructures studied here are grown by molecular beam epitaxy (MBE) on semi-insulating (001) InP substrates using a Riber Compact 21T MBE system. A cross

Peculiarities of thermoelectric half-Heusler phase formation in Gd-Ni-Sb and Lu-Ni-Sb ternary systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romaka, V.V., E-mail: romakav@lp.edu.ua; Romaka, L.; Horyn, A.

The phase equilibria in the Gd–Ni–Sb and Lu-Ni-Sb ternary systems were studied at 873 K by X-ray and metallographic analyses in the whole concentration range. The interaction of the elements in the Gd–Ni–Sb system results the formation of five ternary compounds at investigated temperature: Gd{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), Gd{sub 5}NiSb{sub 2} (Yb{sub 5}Sb{sub 3}-type), GdNiSb (MgAgAs-type), Gd{sub 3}Ni{sub 6}Sb{sub 5} (Y{sub 3}Ni{sub 6}Sb{sub 5}-type), and GdNi{sub 0.72}Sb{sub 2} (HfCuSi{sub 2}-type). At investigated temperature the Lu-Ni-Sb system is characterized by formation of the LuNiSb (MgAgAs-type), Lu{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), and Lu{sub 5}Ni{sub 0.56}Sb{sub 2.44} (Yb{sub 5}Sb{sub 3}-type)more » compounds. The disordering in the crystal structure of half-Heusler GdNiSb and LuNiSb was revealed by EPMA and studied by means of Rietveld refinement and DFT modeling. The performed electronic structure calculations are in good agreement with electrical transport property studies. - Graphical abstract: Crystal structure model and electron localization function of Lu{sub 5}Ni{sub 2}Sb. Display Omitted - Highlights: • Gd-Ni-Sb and Lu-Ni-Sb phase diagrams were constructed at 873 K. • GdNiSb and LuNiSb are characterized by disordered crystal structure. • Crystal structure optimization with DFT calculations confirmed crystal structure disorder in GdNiSb and LuNiSb.« less

Synthesis, Structure, Te Alloying, and Physical Properties of CuSbS 2

DOE PAGES

Hobbis, Dean; Wei, Kaya; Wang, Hsin; ...

2017-10-30

Materials with very low thermal conductivities continue to be of interest for a variety of applications. In this paper, we synthesized CuSbS 2 employing a mechanical alloying technique in order to investigate its physical properties. The trigonal pyramid arrangement of the S atoms around the Sb atoms allows for lone-pair electron formation that results in very low thermal conductivity. Finally, in addition to thermal properties, the structural, electrical, and optical properties, as well as compositional stability measurements, are also discussed. CuSbS 1.8Te 0.2 was similarly synthesized and characterized in order to compare its structural and transport properties with that ofmore » CuSbS 2, in addition to investigating the effect of Te alloying on these properties.« less

Synthesis, Structure, Te Alloying, and Physical Properties of CuSbS 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbis, Dean; Wei, Kaya; Wang, Hsin

Materials with very low thermal conductivities continue to be of interest for a variety of applications. In this paper, we synthesized CuSbS 2 employing a mechanical alloying technique in order to investigate its physical properties. The trigonal pyramid arrangement of the S atoms around the Sb atoms allows for lone-pair electron formation that results in very low thermal conductivity. Finally, in addition to thermal properties, the structural, electrical, and optical properties, as well as compositional stability measurements, are also discussed. CuSbS 1.8Te 0.2 was similarly synthesized and characterized in order to compare its structural and transport properties with that ofmore » CuSbS 2, in addition to investigating the effect of Te alloying on these properties.« less

Lower lattice thermal conductivity in SbAs than As or Sb monolayers: a first-principles study.

PubMed

Guo, San-Dong; Liu, Jiang-Tao

2017-12-06

Phonon transport in group-VA element (As, Sb and Bi) monolayer semiconductors has been widely investigated in theory, and, of them, monolayer Sb (antimonene) has recently been synthesized. In this work, phonon transport in monolayer SbAs is investigated with a combination of first-principles calculations and the linearized phonon Boltzmann equation. It is found that the lattice thermal conductivity of monolayer SbAs is lower than those of both monolayer As and Sb, and the corresponding sheet thermal conductance is 28.8 W K -1 at room temperature. To understand the lower lattice thermal conductivity in monolayer SbAs than those in monolayer As and Sb, the group velocities and phonon lifetimes of monolayer As, SbAs and Sb are calculated. The calculated results show that the group velocities of monolayer SbAs are between those of monolayer As and Sb, but that the phonon lifetimes of SbAs are smaller than those of both monolayer As and Sb. Hence, the low lattice thermal conductivity in monolayer SbAs is attributed to very small phonon lifetimes. Unexpectedly, the ZA branch has very little contribution to the total thermal conductivity, only 2.4%, which is obviously different from those of monolayer As and Sb with very large contributions. This can be explained by very small phonon lifetimes for the ZA branch of monolayer SbAs. The lower lattice thermal conductivity of monolayer SbAs compared to that of monolayer As or Sb can be understood by the alloying of As (Sb) with Sb (As), which should introduce phonon point defect scattering. We also consider the isotope and size effects on the lattice thermal conductivity. It is found that isotope scattering produces a neglectful effect, and the lattice thermal conductivity with a characteristic length smaller than 30 nm can reach a decrease of about 47%. These results may offer perspectives on tuning the lattice thermal conductivity by the mixture of multiple elements for applications of thermal management and

Modal gain characteristics of a 2 μm InGaSb/AlGaAsSb passively mode-locked quantum well laser

NASA Astrophysics Data System (ADS)

Li, Xiang; Wang, Hong; Qiao, Zhongliang; Guo, Xin; Ng, Geok Ing; Zhang, Yu; Niu, Zhichuan; Tong, Cunzhu; Liu, Chongyang

2017-12-01

Passive mode locking with a fundamental repetition rate at ˜18.46 GHz is demonstrated in a two-section InGaSb/AlGaAsSb quantum well laser emitting at 2 μm. Modal gain characteristics of the laser are investigated by performing the Hakki-Paoli method to gain better insight into the impact of the absorber bias voltage (Va) on the light output. The lasing action moves to longer wavelengths markedly with increasing negative Va. The light output contains more longitudinal modes in the mode locking regime if the gain bandwidth is larger at a certain Va. Our findings provide guidelines for output characteristics of the mode-locked laser.

STM/STS Study of the Sb (111) Surface

NASA Astrophysics Data System (ADS)

Chekmazov, S. V.; Bozhko, S. I.; Smirnov, A. A.; Ionov, A. M.; Kapustin, A. A.

An Sb crystal is a Peierls insulator. Formation of double layers in the Sb structure is due to the shift of atomic planes (111) next but one along the C3 axis. Atomic layers inside the double layer are connected by covalent bonds. The interaction between double layers is determined mainly by Van der Waals forces. The cleave of an Sb single crystal used to be via break of Van der Waals bonds. However, using scanning tunneling microscopy (STM) and spectroscopy (STS) we demonstrated that apart from islands equal in thickness to the double layer, steps of one atomic layer in height also exist on the cleaved Sb (111) surface. Formation of "unpaired" (111) planes on the surface leads to a local break of conditions of Peierls transition. STS experiment reveals higher local density of states (LDOS) measured for "unpaired" (111) planes in comparison with those for the double layer.

Comparison of W-VC-C composites against Co-60, Se-75 and Sb-125 for gamma radioisotope sources

NASA Astrophysics Data System (ADS)

Demir, Ertugrul; Tugrul, A. Beril; Buyuk, Bulent; Yilmaz, Ozan; Ovecoglu, Lutfi

2018-02-01

Tungsten based materials are considered to be the promising materials for nuclear applications due to the good properties. The tungsten composite materials have so many advantages in nuclear technological applications especially fusion reactor systems. In this paper, Tungsten-Vanadium carbide-Graphite (W-VC-C) which include 93% tungsten (W), 6% vanadium carbide (VC) and 1% graphite (C) also which has three different alloying time (6-12-24 hours) were produced by mechanical alloying method. Co-60, Se-75 and Sb-125 gamma radioisotopeswere used as a gamma sources in order to determine behavior of gamma attenuation properties of the composite materials. The experimental results were compared with each other to clarify effects of varying gamma energies on the tungsten based composite materials. The mass attenuation coefficients of the samples were obtained by using XCOM computer code and compared with experimental data. The gamma linear attenuation, the mass attenuation coefficients and half value thickness (HVL) of the samples were evaluated and compared with Co-60, Se-75 and Sb-125 for gamma radioisotopes. Results showed that gamma attenuation coefficients of the samples depend on gamma energies and mechanical alloying time has negatively effect on the gamma shielding properties for the all studied W-VC-C.

Centrosymmetry vs noncentrosymmetry in La2Ga0.33SbS5 and Ce4GaSbS9 based on the interesting size effects of lanthanides: Syntheses, crystal structures, and optical properties

NASA Astrophysics Data System (ADS)

Zhao, Hua-Jun

2016-05-01

Two new quaternary sulfides La2Ga0.33SbS5 and Ce4GaSbS9 have been prepared from stoichiometric elements at 1223 K in an evacuated silica tube. Interestingly, La2Ga0.33SbS5 crystallizes in the centrosymmetric structure, while Ce4GaSbS9 crystallizes in the noncentrosymmetric structure, which show obvious size effects of lanthanides on the crystal structures of these two compounds. Ce4GaSbS9 belongs to RE4GaSbS9 (RE=Pr, Nd, Sm, Gd-Ho) structure type with a=13.8834(9) Å, b=14.3004(11) Å, c=14.4102(13) Å, V=2861.0(4) Å3. The structure features infinite chains of [Ga2Sb2S1110-]∞ propagating along a direction separated by Ce3+ cations and S2- anions. La2Ga0.33SbS5 adopts the family of La4FeSb2S10-related structure with a=7.5193(6) Å, c=13.4126(17) Å, V=758.35(13) Å3. Its structure is built up from the alternate stacking of La/Sb/S and La/Ga/S 2D building blocks. The La/Sb/S slabs consist of teeter-totter chains of Sb1S4 seesaws, which are connected via sharing the apexes of μ4-S1. Moreover, La1 is positionally disordered with Sb1 and stabilized in a bicapped trigonal prismatic coordination sphere. Between these La/Sb/S slabs, La2S8 square antiprisms are connected via edge-sharing into 2D building blocks, creating tetrahedral sites partially occupied by the Ga1 atoms. UV/Vis diffuse reflectance spectroscopy study shows that the optical gap of La2Ga0.33SbS5 is about 1.76 eV.

Microstructure and interface analysis of emerging Ga(Sb,Bi) epilayers and Ga(Sb,Bi)/GaSb quantum wells for optoelectronic applications

NASA Astrophysics Data System (ADS)

Luna, E.; Delorme, O.; Cerutti, L.; Tournié, E.; Rodriguez, J.-B.; Trampert, A.

2018-04-01

Using transmission electron microscopy, we present an in-depth microstructural analysis of a series of Ga(Sb,Bi) epilayers and Ga(Sb,Bi)/GaSb quantum wells grown on GaSb(001) substrates by molecular beam epitaxy. Despite the dilute bismide compound Ga(Sb,Bi) is regarded as a highly-mismatched alloy, we find that the material is of remarkable structural perfection, even up to 11%-14% Bi, the maximum Bi concentration incorporated into GaSb so far. No extended defects, nanoclusters, or composition modulations are detectable in the pseudomorphic layers. In addition, the quantum wells exhibit regular and homogeneous morphologies including smooth and stable interfaces with a chemical width on the same order as in other high-quality III-V heterointerfaces. These results may give reasons for the recent successful realization of mid-infrared lasers with room temperature operation based on the very same quantum well structures.

Removal of antimony (Sb(V)) from Sb mine drainage: biological sulfate reduction and sulfide oxidation-precipitation.

PubMed

Wang, Huawei; Chen, Fulong; Mu, Shuyong; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Chang, Jo-Shu

2013-10-01

Antimony (Sb(V)) in Sb mine drainage has adverse effects on the receiving water environments. This study for the first time demonstrated the feasibility of using sulfate-reducing bacteria (SRB) to convert sulfate ions in SMD into sulfides that reduce Sb(V) to Sb(III) and to form complex with Sb(III) as precipitate. The principal compound in the precipitate was stibnite (Sb2S3) at pH 7 and pH 9. The Sb(V) removal mechanism is sulfate-reduction and sulfide oxidization-precipitation, different from the conventional SRB-precipitation processes for heavy metals. The Sb(V)/sulfate ratio is noted an essential parameter affecting the Sb removal efficiency from SMD. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Direct determination of purine bases in tea by reversed-phase high performance liquid chromatography].

PubMed

Ding, M; Yang, H; Xiao, S; Chen, P

1999-09-01

A reversed-phase high performance liquid chromatographic(RP-HPLC) method for the direct determination of three purine bases(theobromin, theophyllin and caffeine) in tea was developed. An ODS column with Zorbax SB-C18(4.6 mm i.d. x 250 mm, 5 microns) was employed. The aqueous solution of methanol containing 0.05% of acetic acid and 0.25% of N,N-dimethylformamide(DMF) was used as eluent with a flow rate of 0.8 mL/min. In this method, the aqueous extract of tea can be injected into HPLC directly, but in current HPLC methods for purine bases the coexisted tea polyphenols must be pre-separated. The three purine bases in tea were separated without any interference from the coexisted tea polyphenols. This method is simple (without any special sample pretreatment) and sensitive with detection limits (S/N = 3) of 0.7, 0.9 and 1.8 mg/L for theobromin, theophyllin and caffeine respectively. The linear range of the calibration curve of peak area for the three purine bases were from 6 mg/L to 1,000 mg/L with a correlation coefficient (r) of 0.998-0.999.

In-situ characterization of the optical and electronic properties in GeTe and GaSb thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velea, A.; Popescu, M.; Galca, A. C., E-mail: ac-galca@infim.ro

2015-10-07

GeTe and GaSb thin films obtained by pulsed laser deposition were investigated by spectroscopic ellipsometry at controlled temperatures. The GeTe films were fully amorphous, while the GaSb films were partially crystalized in the as-deposited state. The Tauc-Lorentz model was employed to fit the experimental data. From the temperature study of the optical constants, it was observed the crystallization in the 150–160 °C range of GeTe amorphous films and between 230 and 240 °C of GaSb amorphous phase. A second transition in the resonance energy and the broadening parameter of the Lorentz oscillator was observed due to the crystallization of Sb after 250 °C.more » The temperatures of 85 °C and 130 °C are noticed as the start of the relaxation of the amorphous GeTe phase and as-deposited GaSb. The peaks of the imaginary part of the dielectric function red shifted after the phase change, while the variation with temperature of the crystalline phase follows the Varshni law. The electron-phonon coupling constants are 2.88 and 1.64 for c-GeTe and c-GaSb, respectively. An optical contrast up to 60% was obtained for GeTe films and a maximum value of 7.5% is revealed in the case GaSb, which is altered by the partial crystallinity of the as-deposited films.« less

Method of making AlInSb by metal-organic chemical vapor deposition

DOEpatents

Biefeld, Robert M.; Allerman, Andrew A.; Baucom, Kevin C.

2000-01-01

A method for producing aluminum-indium-antimony materials by metal-organic chemical vapor deposition (MOCVD). This invention provides a method of producing Al.sub.X In.sub.1-x Sb crystalline materials by MOCVD wherein an Al source material, an In source material and an Sb source material are supplied as a gas to a heated substrate in a chamber, said Al source material, In source material, and Sb source material decomposing at least partially below 525.degree. C. to produce Al.sub.x In.sub.1-x Sb crystalline materials wherein x is greater than 0.002 and less than one.

Transport properties of Sb doped Si nanowires

NASA Astrophysics Data System (ADS)

Nukala, Prathyusha; Sapkota, Gopal; Gali, Pradeep; Usha, Philipose

2011-10-01

n-type Si nanowires were synthesized at ambient pressure using SiCl4 as Si source and Sb source as the dopant. Sb doping of 3-4 wt % was achieved through a post growth diffusion technique. The nanowires were found to have an amorphous oxide shell that developed post-growth; the thickness of the shell is estimated to be about 3-4 nm. The composition of the amorphous shell covering the crystalline Si core was determined by Raman spectroscopy, with evidence that the shell was an amorphous oxide layer. Optical characterization of the as-grown nanowires showed green emission, attributed to the presence of the oxide shell covering the Si nanowire core. Etching of the oxide shell was found to decrease the intensity of this green emission. A single undoped Si nanowire contacted in an FET type configuration was found to be p-type with channel mobility of 20 cm^2V-1S-1. Sb doped Si nanowires exhibited n-type behavior, compensating for the holes in the undoped nanowire. The doped nanowires had carrier mobility and concentration of 160 cm^2V-1S-1 and 9.6 x 10^18cm-3 respectively.

2.4 Micron Cutoff AlGaAsSb/InGaAsSb Phototransistors for Shortwave IR Applications

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Abedin, Nurul; Sulima, Oleg V.; Swaminathan, Krishna; Ismail, Syed; Singh, Upendra N.

2006-01-01

Shortwave infrared detectors are critical for several applications including remote sensing and optical communications. Several detectors are commercially available for this wavelength range, but they lack sufficient gain, which limits their detectivity. The characterization results of an AlGaAsSb/InGaAsSb phototransistor for shortwave IR application are reported. The phototransistor is grown using molecular beam epitaxy technique. Spectral response measurements showed a uniform responsivity between 1.2 and 2.4 micron region with a mean value of 1000 A/W. A maximum detectivity of 3.4 X 10(exp 11) cmHz1/2/W was obtained at 2 micron at -20 C and 1.3 V.

Effect of InSb/In0.9Al0.1Sb superlattice buffer layer on the structural and electronic properties of InSb films

NASA Astrophysics Data System (ADS)

Zhao, Xiaomeng; Zhang, Yang; Guan, Min; Cui, Lijie; Wang, Baoqiang; Zhu, Zhanping; Zeng, Yiping

2017-07-01

The effect of InSb/In0.9Al0.1Sb buffer layers on InSb thin films grown on GaAs (0 0 1) substrate by molecular beam epitaxy (MBE) is investigated. The crystal quality and the surface morphology of InSb are characterized by XRD and AFM. The carrier transport property is researched through variable temperature hall test. The sharp interface between InSb/In0.9Al0.1Sb is demonstrated important for the high quality InSb thin film. We try different superlattice buffer layers by changing ratios, 2-0.5, thickness, 300-450 nm, and periods, 20-50. According to the function of the dislocation density to the absolute temperature below 150 K with different periods of SL buffers, we can find that the number of periods of superlattice is a major factor to decrease the density of threading dislocations. With the 50 periods SL buffer layer, the electron mobility of InSb at the room temperature and liquid nitrogen cooling temperature is ∼63,000 and ∼4600 cm2/V s, respectively. We deduce that the interface in the SL structure works as a filter layer to prevent the dislocation propagating to the upper InSb thin films.

Electric measurement and magnetic control of spin transport in InSb-based lateral spin devices

NASA Astrophysics Data System (ADS)

Viglin, N. A.; Ustinov, V. V.; Demokritov, S. O.; Shorikov, A. O.; Bebenin, N. G.; Tsvelikhovskaya, V. M.; Pavlov, T. N.; Patrakov, E. I.

2017-12-01

Electric injection and detection of spin-polarized electrons in InSb semiconductors have been realized in nonlocal experimental geometry using an InSb-based "lateral spin valve." The valve of the InSb /MgO /C o0.9F e0.1 composition has semiconductor/insulator/ferromagnet nanoheterojunctions in which the thickness of the InSb layer considerably exceeded the spin diffusion length of conduction electrons. The spin direction in spin diffusion current has been manipulated by a magnetic field under the Hanle effect conditions. The spin polarization of the electron gas has been registered using ferromagnetic C o0.9F e0.1 probes by measuring electrical potentials arising in the probes in accordance with the Johnson-Silsbee concept of the spin-charge coupling. The developed theory is valid at any degree of degeneracy of electron gas in a semiconductor. The spin relaxation time and spin diffusion length of conduction electrons in InSb have been determined, and the electron-spin polarization in InSb has been evaluated for electrons injected from C o0.9F e0.1 through an MgO tunnel barrier.

Strain-Balanced InAs/InAs1-xSbx Type-II Superlattices Grown by Molecular Beam Epitaxy on GaSb Substrates

DTIC Science & Technology

2011-12-21

C. Four samples A, B, C, and D with 20 period SLs were grown under identical condi- tions with varying Sb/(Asþ Sb) beam equivalent pressure ( BEP ) flux...incorporation can be achieved. Thus, the InAs1xSbx layers in samples A, B, C, and D have Sb/(AsþSb) BEP ratios of 0.32, 0.347, 0.378, and 0.412

GaSbBi/GaSb quantum-well and wire laser diodes

NASA Astrophysics Data System (ADS)

Ridene, Said

2018-06-01

In this work, we present detailed theoretical studies of the optical gain spectra and the emission wavelength of GaSb1-xBix/GaSb and traditional GaAs1-xBix/GaAs dilute-bismide quantum wells and wires (QWs, QWRs) focusing on comparison between their performances. It is found that the optical gain and the emission wavelength of the GaSb-based QW and QWRs lasers would be considerably greater than that of the GaAs-based QW lasers and QWRs for the same QW-, QWR-width, Bi-content and carrier density. The theoretical results were found to be in good agreement with available experimental data, especially for the emission wavelength given by GaSb-based QW laser diodes.

Fully epitaxial C1b-type NiMnSb half-Heusler alloy films for current-perpendicular-to-plane giant magnetoresistance devices with a Ag spacer

PubMed Central

Wen, Zhenchao; Kubota, Takahide; Yamamoto, Tatsuya; Takanashi, Koki

2015-01-01

Remarkable magnetic and spin-dependent transport properties arise from well-designed spintronic materials and heterostructures. Half-metallic Heusler alloys with high spin polarization exhibit properties that are particularly advantageous for the development of high-performance spintronic devices. Here, we report fully (001)-epitaxial growth of a high-quality half-metallic NiMnSb half-Heusler alloy films, and their application to current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices with Ag spacer layers. Fully (001)-oriented NiMnSb epitaxial films with very flat surface and high magnetization were prepared on Cr/Ag-buffered MgO(001) single crystalline substrates by changing the substrate temperature. Epitaxial CPP-GMR devices using the NiMnSb films and a Ag spacer were fabricated, and room-temperature (RT) CPP-GMR ratios for the C1b-type half-Heusler alloy were determined for the first time. A CPP-GMR ratio of 8% (21%) at RT (4.2 K) was achieved in the fully epitaxial NiMnSb/Ag/NiMnSb structures. Furthermore, negative anisotropic magnetoresistance (AMR) ratio and small discrepancy of the AMR amplitudes between RT and 10 K were observed in a single epitaxial NiMnSb film, indicating robust bulk half metallicity against thermal fluctuation in the half-Heusler compound. The modest CPP-GMR ratios could be attributed to interface effects between NiMnSb and Ag. This work provides a pathway for engineering a new class of ordered alloy materials with particular emphasis on spintronics. PMID:26672482

Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

NASA Astrophysics Data System (ADS)

Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

2016-10-01

The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

Structural and Optical Characteristics of Metamorphic Bulk InAsSb

DTIC Science & Technology

2014-01-01

0.815 0.820 0.825 InAsSb 5 /a ⊥ ( Å ) 3√2/a|| (Å) 0.25 0.40 0.75 1.3 1.5 1.8 2.2 hkl = 335 GaSb Structural and Optical Characteristics of Metamorphic...Conduction- and Valence- Band Energies in Bulk InAs1−xSbx and Type II InAs1−xSbx/InAs Strained-Layer Superlattices”, J. of Electron. Mater., 42, 918...0188 3. DATES COVERED (From - To) - UU UU UU UU Approved for public release; distribution is unlimited. Structural and Optical Characteristics of

New Antimony Lanthanide Disulfide Dibromides LnSbS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gout, D.; Jobic, S.; Evain, M.

2001-05-01

CeSbS{sub 2}Br{sub 2} (I), Ce{sub 1/2}La{sub 1/2}SbS{sub 2}Br{sub 2} (II), and LaSbS{sub 2}Br{sub 2} (III) have been synthesized at 700 C from a mixture of LnBr{sub 3}, Ln{sub 2}S{sub 3}, Sb, and S and characterized by single-crystal X-ray diffraction. The three phases are isostructural (space group P2{sub 1}/c, Z=4) and crystallize in a novel, dense, bidimensional structure with cell parameters a=8.709(3) {angstrom}, b=9.187(2) {angstrom}, c=17.397(5) {angstrom} {beta}=104.26(3) for I, a=8.739(7) {angstrom}, b=9.219(7) {angstrom}, c=17.41(2) {angstrom}, =104.3(1) for II, and a=8.785(1) {angstrom}, b=9.236(2) {angstrom}, c=17.372(3) {angstrom}, {beta}=104.09(2) for III. In these compounds, [Ln S{sub 5}Br{sub 4}] and [Ln S{sub 3}Br{sub 6}]more » (Ln=Ce, La) distorted tricapped trigonal prisms define infinite {sub {infinity}}{sup 2}[LnS{sub 2}Br{sub 2}] layers counterbalanced and capped by antimony cations. In good accordance with the structural features, the charge balance in these materials is to be written Ln{sup III}Sb{sup III}S{sup -II}{sub 2}Br{sup -I}{sub 2}. These compounds exhibit a yellow hue with a measured absorption threshold of 2.42(1), 2.55(1), and 2.72(1) eV for I, II, and III, respectively. In the two cerium containing bromothioantimonates I and II, the origin of the color is assigned to a Ce-4f{yields}Ce-5d electronic transition, which shifts to higher energy from I to II due either to a matrix effect (increase of the mean Ln-S distances under the substitution of Ce for La) or to an atomic ordering between Ce and La cations on the Ln(1) and Ln(2) crystallographic sites. In contrast, the electronic transition at play in III involves a charge transfer from the bromine and sulfur ions to the antimony ions, the latter contributing substantially to the lowermost levels of the conduction band.« less

Fermi Level Unpinning of GaSb (100) using Plasma Enhanced Atomic Layer Deposition of Al2O3

DTIC Science & Technology

2010-01-01

of high-/GaSb semiconductor interface. GaSb has a highly reactive surface and on exposure to air it will form a native oxide layer composed of Ga2O3 ...and Sb2O3 2GaSb+3O2→ Ga2O3 +Sb2O3. The Sb2O3 can fur- ther react with the GaSb surface forming elemental Sb and Ga2O3 Sb2O3+2GaSb→ Ga2O3 +4Sb.5,6...rights_and_permissions mentioned before, Sb2O3 reacts with GaSb forming Ga2O3 and elemental Sb.6 The kinetics of this reaction is enhanced at higher temperatures200 °C.14

Superconductivity in strong spin orbital coupling compound Sb 2Se 3

DOE PAGES

Kong, P. P.; Sun, F.; Xing, L. Y.; ...

2014-10-20

Recently, A 2B 3 type strong spin orbital coupling compounds such as Bi 2Te 3, Bi 2Se 3 and Sb 2Te 3 were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb 2Se 3 on the other hand was found to be topological trivial, but theoretical studies indicated that the pressure might induce Sb 2Se 3 into a topological nontrivial state. We report on the discovery of superconductivity in Sb 2Se 3 single crystal induced via pressure. Our experiments indicated that Sb 2Se 3 became superconductive at high pressures above 10 GPa proceeded bymore » a pressure induced insulator to metal like transition at ~3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (T C) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. As a result, high pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of T C slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.« less

Experimental and theoretical investigation of topological and energetic characteristics of Sb complexes reversibly binding molecular oxygen.

PubMed

Fukin, Georgy K; Baranov, Evgenii V; Jelsch, Christian; Guillot, Benoît; Poddel'sky, Andrey I; Cherkasov, Vladimir K; Abakumov, Gleb A

2011-07-28

The experimental distribution of electron density in Ph(3)(4,5-OMe-3,6-Bu(t)-Cat)Sb·MeCN (1*) and Ph(3)(4,5-N(2)C(4)H(6)-3,6-Bu(t)-Cat)Sb·MeOH (2*) complexes was studied. According to atoms in molecules theory, the Sb-C(Ph), Sb-O(catecholate), and Sb···N(O) bonds are intermediate, whereas the O-C and C-C bonds are covalent, respectively. The energy of the Sb···N(MeCN) and Sb···O(MeOH) bonds are 7.0 and 11.3 kcal/mol according to the Espinosa equation. Density functional theory and Hartree-Fock calculations were carried out for a series of catecholate and amidophenolate complexes of antimony(V). It was shown that such calculations reliably reproduce geometrical and topological parameters and therefore can be used for a criterion search of dioxygen reversible binding by the catecholate and amidophenolate complexes of antimony(V). It was found that the "critical" value of the HOMO energy vary in the range from -5.197 to -5.061 eV for reversible binding of dioxygen complexes. This can serve as a thermodynamic criterion to predict the possibility of the dioxygen reversible binding by the catecholate and amidophenolate complexes of Sb(V). The HOMO energies correlate with the conversion of the catecholate and amidophenolate complexes in corresponding spiroendoperoxide derivatives as well. The contribution of the atom orbitals of the carbon atoms in the five-membered metallocycle to HOMO in complexes with different substitutes in the 4- and 5-positions of the catecholate ligand allows predicting the place of dioxygen addition. © 2011 American Chemical Society

[Application of fingerprint chromatogram in quality assessment of apple cider].

PubMed

Xu, Kangzhen; Song, Jirong; Ren, Yinghui; Ma, Haixia; Huang, Jie; Du, Xiaodan

2007-01-01

Fingerprints of 14 apple cider samples from different manufacturers were studied using high performance liquid chromatography (HPLC) with an electrochemical detector (ECD). The analysis was carried out on a Zorbax SB-C18 column at 30 degrees C with 2% (v/v) methanol aqueous solution-4% (v/v) acetic acid aqueous solution as mobile phase at a flow rate of 0.8 mL/min. The electrochemical detector was set at 0.7 V. By calculating the relative retention times of certain peaks with chlorogenic acid as the reference standard, 8 common peaks in the samples were analyzed. Relative retention times for the common peaks of various samples were calculated, and the similarities of all the samples were figured out through each peak area with the vectorial angle cosine method and correlative coefficient method. The results indicated that apple cider products of the same manufacturer have good similarity, with the similarities greater than 92.7%. According to this experiment, effectual microcosmic information for apple cider analysis was gained through HPLC and ECD. Moreover, this test method will help the analysis and the control of product quality, the development of new products and the establishment of trade standard.

Method of making an InAsSb/InAsSbP diode lasers

DOEpatents

Razeghi, Manijeh

1997-01-01

InAsSb/InAsSbP/InAs Double Heterostructures (DH) and Separate Confinement Heterostructure Multiple Quantum Well (SCH-MQW) structures are taught wherein the ability to tune to a specific wavelength within 3 .mu.m to 5 .mu.m is possible by varying the ratio of As:Sb in the active layer.

Low temperature Zn diffusion for GaSb solar cell structures fabrication

NASA Technical Reports Server (NTRS)

Sulima, Oleg V.; Faleev, Nikolai N.; Kazantsev, Andrej B.; Mintairov, Alexander M.; Namazov, Ali

1995-01-01

Low temperature Zn diffusion in GaSb, where the minimum temperature was 450 C, was studied. The pseudo-closed box (PCB) method was used for Zn diffusion into GaAs, AlGaAs, InP, InGaAs and InGaAsP. The PCB method avoids the inconvenience of sealed ampoules and proved to be simple and reproducible. The special design of the boat for Zn diffusion ensured the uniformality of Zn vapor pressure across the wafer surface, and thus the uniformity of the p-GaSb layer depth. The p-GaSb layers were studied using Raman scattering spectroscopy and the x-ray rocking curve method. As for the postdiffusion processing, an anodic oxidation was used for a precise thinning of the diffused GaSb layers. The results show the applicability of the PCB method for the large-scale production of the GaSb structures for solar cells.

Relation between the magnetization and the electrical properties of alloy GaSb-MnSb films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koplak, O. V.; Polyakov, A. A.; Davydov, A. B.

2015-06-15

The influence of the charge carrier concentration on the magnetic properties of GaSb-MnSb alloys is studied. The ferromagnetism of GaSb-MnSb films is caused by the presence of MnSb granules and manifests itself in both magnetometric measurements and the presence of an anisotropic magnetoresistance and the anomalous Hall effect. Electric conduction is executed by charge carriers (holes) in a GaSb matrix. The magnetization of clusters depends on stoichiometry and the concentration of Mn{sup 2+} and Mn{sup 3+} ions, which is specified by the film growth conditions. At high film growth temperatures, ferromagnetic clusters containing Mn{sup 2+} ions mainly form. At lowmore » growth temperatures, an antiferromagnetic phase containing Mn{sup 3+} ions forms.« less

Method of making an InAsSb/InAsSbP diode lasers

DOEpatents

Razeghi, M.

1997-08-19

InAsSb/InAsSbP/InAs Double Heterostructures (DH) and Separate Confinement Heterostructure Multiple Quantum Well (SCH-MQW) structures are taught wherein the ability to tune to a specific wavelength within 3 {micro}m to 5 {micro}m is possible by varying the ratio of As:Sb in the active layer. 9 figs.

Chemical investigation of saponins in different parts of Panax notoginseng by pressurized liquid extraction and liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Wan, Jian-Bo; Zhang, Qing-Wen; Hong, Si-Jia; Li, Peng; Li, Shao-Ping; Wang, Yi-Tao

2012-05-16

A pressurized liquid extraction (PLE) and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acetate as mobile phase. The mass spectrometer was operated in the negative ion mode using the electrospray ionization, and a collision induced dissociation (CID) experiment was also carried out to aid the identification of compounds. Forty one saponins were identified in different parts of P. notoginseng according to the fragmentation patterns and literature reports, among them, 21 saponins were confirmed by comparing the retention time and ESI-MS data with those of standard compounds. The results showed that the chemical characteristics were obviously diverse in different parts of P. notoginseng, which is helpful for pharmacological evaluation and quality control of P. notoginseng.

[Simultaneous determination of 4 diterpenoids in Rabdosia japonica var.glaucocalyx by HPLC-ESI-MS/MS and cluster analysis].

PubMed

Tian, Ting-Ting; Ma, Ying-Hua; Xie, Wei-Wei; Jin, Yi-Ran; Xu, Hui-Jun; Zhang, Lan-Tong; Du, Ying-Feng

2016-01-01

A quick HPLC-ESI-MS/MS method was established for simultaneous determination of four major diterpenoids in Rabdosia japonica var.glaucocalyx, including glaucocalyxin A, oridonin, hebeirubesensin and enmenol. Analysis was performed on an Agilent ZORBAX SB-C18(4.6 mm×250 mm, 5 μm ) column eluted in a gradient program with methanol and water. The flow rate was 0.8 mL•min⁻¹. Multiple reaction monitoring (MRM) scanning mode was performed in negative ion switching mode to apply for the quantitative determination. The calibration curves for the above four compounds were linear in corresponding injection amount. The average recoveries of the compounds ranged from 92.40% to 105.9%, with RSDs of 1.7%-6.5%. The method is simple, rapid, accurate with good repeatability, which can provide a reference for overcalling evaluation the quality of R. japonica var.glaucocalyx. The result of cluster analysis- showed that the quality of R. japonica glaucocalyx var. greatly varied between areas and parts. Copyright© by the Chinese Pharmaceutical Association.

Development and validation of an LC-MS method for determination of Karanjin in rat plasma: application to preclinical pharmacokinetics.

PubMed

Yi, Deliang; Wang, Zhihua; Yi, Longzhi

2015-04-01

A selective and sensitive liquid chromatography-mass spectrometry (MS) method was developed and validated for the determination of karanjin in rat plasma. The target analyte, together with the internal standard (warfarin), was extracted from rat plasma by liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a ZORBAX SB-C18 column using a mixture of acetonitrile and 0.1% aqueous formic acid as the mobile phase with linear gradient elution. MS detection was performed on a single quadrupole MS by selected ion monitoring mode via a positive electrospray ionization source. The assay exhibited a linear dynamic range of 2.50-3,000 ng/mL for karanjin. The intra- and inter-day precision was <10.8%, and the intra- and inter-day accuracy was <9.2%. The validated method has been applied to the preclinical pharmacokinetic studies of karanjin following oral administration of 5, 10 and 20 mg/kg karanjin to rats. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sb2O3/Ag/Sb2O3 Multilayer Transparent Conducting Films For Ultraviolet Organic Light-emitting Diode

NASA Astrophysics Data System (ADS)

Song, Chunyan; Zhang, Nan; Lin, Jie; Guo, Xiaoyang; Liu, Xingyuan

2017-01-01

A novel UV transparent conducting films based on Sb2O3/Ag/Sb2O3 (SAS) structure, which were prepared by an electron-beam thermal evaporation at room temperature. This SAS exhibits excellent electrical, optical and stable properties. Especially for UV region, the SAS has high transmittance of 80% at 306 nm and 92% at 335 nm, meanwhile achieving low sheet resistance ( ≤ 10 Ω sq-1). The UV OLED based on the SAS show competitive device performance. The UV OLED obtains the peak of UV electroluminescence at 376 nm and shows a very high maximum EQE of 4.1% with the maximum output power density of 5.18 mW cm-2. These results indicate that the potential of SAS applications in deep UV transparent electrodes and large-scale flexible transparent electronics.

Sb2O3/Ag/Sb2O3 Multilayer Transparent Conducting Films For Ultraviolet Organic Light-emitting Diode.

PubMed

Song, Chunyan; Zhang, Nan; Lin, Jie; Guo, Xiaoyang; Liu, Xingyuan

2017-01-25

A novel UV transparent conducting films based on Sb 2 O 3 /Ag/Sb 2 O 3 (SAS) structure, which were prepared by an electron-beam thermal evaporation at room temperature. This SAS exhibits excellent electrical, optical and stable properties. Especially for UV region, the SAS has high transmittance of 80% at 306 nm and 92% at 335 nm, meanwhile achieving low sheet resistance ( ≤ 10 Ω sq -1 ). The UV OLED based on the SAS show competitive device performance. The UV OLED obtains the peak of UV electroluminescence at 376 nm and shows a very high maximum EQE of 4.1% with the maximum output power density of 5.18 mW cm -2 . These results indicate that the potential of SAS applications in deep UV transparent electrodes and large-scale flexible transparent electronics.

W-Sb-Te phase-change material: A candidate for the trade-off between programming speed and data retention

NASA Astrophysics Data System (ADS)

Peng, Cheng; Wu, Liangcai; Rao, Feng; Song, Zhitang; Yang, Pingxiong; Song, Hongjia; Ren, Kun; Zhou, Xilin; Zhu, Min; Liu, Bo; Chu, Junhao

2012-09-01

W-Sb-Te phase-change material has been proposed to improve the performance of phase-change memory (PCM). Crystallization temperature, crystalline resistance, and 10-year data retention of Sb2Te increase markedly by W doping. The Wx(Sb2Te)1-x films crystallize quickly into a stable hexagonal phase with W uniformly distributing in the crystal lattice, which ensures faster SET speed and better operation stability for the application in practical device. PCM device based on W0.07(Sb2Te)0.93 shows ultrafast SET operation (6 ns) and good endurance (1.8 × 105 cycles). W-Sb-Te material is a promising candidate for the trade-off between programming speed and data retention.

Crystal growth and characterization of bulk Sb2Te3 topological insulator

NASA Astrophysics Data System (ADS)

Sultana, Rabia; Gurjar, Ganesh; Patnaik, S.; Awana, V. P. S.

2018-04-01

The Sb2Te3 crystals are grown using the conventional self flux method via solid state reaction route, by melting constituent elements (Sb and Te) at high temperature (850 °C), followed by slow cooling (2 °C/h). As grown Sb2Te3 crystals are analysed for various physical properties by x-ray diffraction (XRD), Raman Spectroscopy, Scanning Electron Microscopy (SEM) coupled with Energy Dispersive x-ray Spectroscopy (EDAX) and electrical measurements under magnetic field (6 Tesla) down to low temperature (2.5 K). The XRD pattern revealed the growth of synthesized Sb2Te3 sample along (00l) plane, whereas the SEM along with EDAX measurements displayed the layered structure with near stoichiometric composition, without foreign contamination. The Raman scattering studies displayed known ({{{{A}}}1{{g}}}1, {{{{E}}}{{g}}}2 and {{{{A}}}1{{g}}}2) vibrational modes for the studied Sb2Te3. The temperature dependent electrical resistivity measurements illustrated the metallic nature of the as grown Sb2Te3 single crystal. Further, the magneto—transport studies represented linear positive magneto-resistance (MR) reaching up to 80% at 2.5 K under an applied field of 6 Tesla. The weak anti localization (WAL) related low field (±2 Tesla) magneto-conductance at low temperatures (2.5 K and 20 K) has been analysed and discussed using the Hikami—Larkin—Nagaoka (HLN) model. Summarily, the short letter reports an easy and versatile method for crystal growth of bulk Sb2Te3 topological insulator (TI) and its brief physical property characterization.

Phase Change Characteristics of InxSb40-xTe60 Chalcogenide Alloy for Phase Change Random Access Memory

NASA Astrophysics Data System (ADS)

Yun, Jae-Jin; Lee, Won-Jong

2011-07-01

The InxSb40-xTe60 alloy was selected as a new alternative phase change material for Ge2Sb2Te5 (GST) for phase change random access memory (PRAM). The crystal structure of InxSb40-xTe60 was an α(Sb2Te3) rhombohedral (a=b=c, α=β=γ≠90°) single phase with identical lattice parameters in a wide composition range of In (0-28 at. %). The crystallization temperature and melting point of InxSb40-xTe60 were in the ranges of 149-219 °C and 608-614 °C, respectively, and similar to those of GST. The electric properties of InxSb40-xTe60 with a wide composition range of In contents showed the typical PRAM properties such as current-voltage (I-V), resistance-voltage (R-V), and switching behavior. The reset current of InxSb40-xTe60 decreased with increasing In content and the low power consumption and good retention can be realized by controlling In content. The ratio of the cell resistance and sheet resistance of amorphous InxSb40-xTe60 to those crystalline InxSb40-xTe60 were almost the same as or larger than those of GST. The cycling endurance test of InxSb40-xTe60 with a wide range of In contents showed the comparable results to GST. InxSb40-xTe60 was concluded to be a very promising phase change material for PRAM.

[Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}: A designer all-metal aromatic sandwich

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Wen-Juan; You, Xue-Rui; Guo, Jin-Chang

We report on the computational design of an all-metal aromatic sandwich, [Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}. The triple-layered, square-prismatic sandwich complex is the global minimum of the system from Coalescence Kick and Minima Hopping structural searches. Following a standard, qualitative chemical bonding analysis via canonical molecular orbitals, the sandwich complex can be formally described as [Sb{sub 4}]{sup +}[Au{sub 4}]{sup 4−}[Sb{sub 4}]{sup +}, showing ionic bonding characters with electron transfers in between the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers. For an in-depth understanding of the system, one needs to go beyond the above picture. Significant Sb → Au donation and Sb ←more » Au back-donation occur, redistributing electrons from the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers to the interlayer Sb–Au–Sb edges, which effectively lead to four Sb–Au–Sb three-center two-electron bonds. The complex is a system with 30 valence electrons, excluding the Sb 5s and Au 5d lone-pairs. The two [Sb{sub 4}]{sup +} ligands constitute an unusual three-fold (π and σ) aromatic system with all 22 electrons being delocalized. An energy gap of ∼1.6 eV is predicted for this all-metal sandwich. The complex is a rare example for rational design of cluster compounds and invites forth-coming synthetic efforts.« less

The section TiInSe/sub 2/-TiSbSe/sub 2/ of the system Ti-In-Sb-Se

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guseinov, G.D.; Chapanova, L.M.; Mal'sagov, A.U.

1985-09-01

The ternary compounds A /SUP I/ B /SUP III/ C/sub 2/ /SUP VI/ (A /SUP I/ is univalent Ti; B /SUP III/ is Ga or In; and C /SUP VI/ is S, Se or Te) form a class of semiconductors with a large number of different gap widths. The compounds crystallize in the chalcopyrite structure. Solid solutions based on these compounds, which permit varying smoothly the gap width and other physical parameters over wide limits, are of great interest. The authors synthesized the compounds TiInSe/sub 2/ and TiSbSe/sub 2/ from the starting materials Ti-000, In-000, Sb-000 and Se-OSCh-17-4 by directmore » fusion of the components, taken in a stoichiometric ratio, in quartz ampules evacuated to 1.3 X 10/sup -3/ Pa and sealed.« less

Ab Initio Molecular Dynamics Studies of Pb m Sb n ( m + n ≤ 9) Alloy Clusters

NASA Astrophysics Data System (ADS)

Song, Bingyi; Xu, Baoqiang; Yang, Bin; Jiang, Wenlong; Chen, Xiumin; Xu, Na; Liu, Dachun; Dai, Yongnian

2017-10-01

Structure, stability, and dynamics of Pb m Sb n ( m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of Pb m Sb n clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 ( n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).

Optical parameters of diode lasers based on an InAsSb/InAsSbP heterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Astakhova, A. P.; Bez'yazychnaya, T. V.; Burov, L. I.

2008-02-15

The rates of radiative recombination (including transitions induced by enhanced luminescence) and nonradiative recombination, internal quantum yield of luminescence, and the matrix element for band-to-band optical transitions were determined for the first time for InAsSb/InAsSbP diode lasers oscillating at wavelengths of 3.1-3.2 {mu}m. It is established that the contribution of nonradiative recombination to the lasing threshold can be as large as 97%. The internal quantum yield of luminescence for the InAs{sub 0.97}Sb{sub 0.03} compound is no higher than 3%. Most likely, the nonradiative channel is formed with involvement of Auger recombination with the constant C = 4.2 Multiplication-Sign 10{sup -38}more » m{sup 6}s{sup -1} (T = 77 K). The studied samples of lasers feature relatively low optical losses {rho} = 900 m{sup -1} and internal quantum efficiency of emission at the level of 0.6. The spontaneous lifetime of nonequilibrium charge carriers as determined from the radiative-recombination rate is equal to 6 Multiplication-Sign 10{sup -8} s, which is consistent with known published data.« less

Optical parameters of diode lasers based on an InAsSb/InAsSbP heterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Astakhova, A. P.; Bez'yazychnaya, T. V.; Burov, L. I.

2008-02-15

The rates of radiative recombination (including transitions induced by enhanced luminescence) and nonradiative recombination, internal quantum yield of luminescence, and the matrix element for band-to-band optical transitions were determined for the first time for InAsSb/InAsSbP diode lasers oscillating at wavelengths of 3.1-3.2 {mu}m. It is established that the contribution of nonradiative recombination to the lasing threshold can be as large as 97%. The internal quantum yield of luminescence for the InAs{sub 0.97}Sb{sub 0.03} compound is no higher than 3%. Most likely, the nonradiative channel is formed with involvement of Auger recombination with the constant C = 4.2 x 10{sup -38}more » m{sup 6}s{sup -1} (T = 77 K). The studied samples of lasers feature relatively low optical losses {rho} = 900 m{sup -1} and internal quantum efficiency of emission at the level of 0.6. The spontaneous lifetime of nonequilibrium charge carriers as determined from the radiative-recombination rate is equal to 6 x 10{sup -8} s, which is consistent with known published data.« less

Surface phase stability and surfactant behavior of InAsSb alloy surfaces.

NASA Astrophysics Data System (ADS)

Anderson, Evan M.; Lundquist, Adam M.; Pearson, Chris; Millunchick, Joanna M.

InAsSb has the narrowest bandgap of any of the conventional III-V semiconductors: low enough for long wavelength infrared applications. Such devices are sensitive to point defects, which can be detrimental to performance. To control these defects, all aspects of synthesis must be considered, especially the atomic bonding at the surface. We use an ab initio statistical mechanics approach that combines density functional theory with a cluster expansion formalism to determine the stable surface reconstructions of Sb (As) on InAs (InSb) substrates. The surface phase diagram of Sb on InAs is dominated by Sb-dimer termination α2(2x4) and β2(2x4) and c(4x4). Smaller regions of mixed Sb-As dimers appear for high Sb chemical potentials and intermediate As chemical potential. We propose that InAsSb films could be grown on (2x4), which maintain bulk-like stoichiometry, to eliminate the formation of typically observed n-type defects. Scanning tunneling microscopy and reflection high energy electron diffraction confirm the calculated phase diagram. Based on these calculations, we propose a new mechanism for the surfactant behavior of Sb in these materials. We gratefully acknowledge Chakrapani Varanasi and the support of the Department of Defense, Army Research Office via the Grant Number W911NF-12-1-0338.

Modeling the thermal conductivities of the zinc antimonides ZnSb and Zn4Sb3

NASA Astrophysics Data System (ADS)

Bjerg, Lasse; Iversen, Bo B.; Madsen, Georg K. H.

2014-01-01

ZnSb and Zn4Sb3 are interesting as thermoelectric materials because of their low cost and low thermal conductivity. We introduce a model of the lattice thermal conductivity which is independent of fitting parameters and takes the full phonon dispersions into account. The model is found to give thermal conductivities with the correct relative magnitudes and in reasonable quantitative agreement with experiment for a number of semiconductor structures. The thermal conductivities of the zinc antimonides are reviewed and the relatively large effect of nanostructuring on the zinc antimonides is rationalized in terms of the mean free paths of the heat carrying phonons. The very low thermal conductivity of Zn4Sb3 is found to be intrinsic to the structure. However, the low-lying optical modes are observed in both Zn-Sb structures and involve both Zn and Sb vibrations, thereby strongly questioning dumbbell rattling. A mechanism for the very low thermal conductivity observed in Zn4Sb3 is identified. The large Grüneisen parameter of this compound is traced to the Sb atoms which coordinate only Zn atoms.

Limiting scattering processes in high-mobility InSb quantum wells grown on GaSb buffer systems

NASA Astrophysics Data System (ADS)

Lehner, Ch. A.; Tschirky, T.; Ihn, T.; Dietsche, W.; Keller, J.; Fält, S.; Wegscheider, W.

2018-05-01

We present molecular beam epitaxial grown single- and double-side δ -doped InAlSb/InSb quantum wells with varying distances down to 50 nm to the surface on GaSb metamorphic buffers. We analyze the surface morphology as well as the impact of the crystalline quality on the electron transport. Comparing growth on GaSb and GaAs substrates indicates that the structural integrity of our InSb quantum wells is solely determined by the growth conditions at the GaSb/InAlSb transition and the InAlSb barrier growth. The two-dimensional electron gas samples show high mobilities of up to 349 000 cm2/Vs at cryogenic temperatures and 58 000 cm2/Vs at room temperature. With the calculated Dingle ratio and a transport lifetime model, ionized impurities predominantly remote from the quantum well are identified as the dominant source of scattering events. The analysis of the well-pronounced Shubnikov-de Haas oscillations reveals a high spin-orbit coupling with an effective g -factor of -38.4 in our samples. Along with the smooth surfaces and long mean free paths demonstrated, our InSb quantum wells are increasingly competitive for nanoscale implementations of Majorana mode devices.

SB265610 is an allosteric, inverse agonist at the human CXCR2 receptor

PubMed Central

Bradley, ME; Bond, ME; Manini, J; Brown, Z; Charlton, SJ

2009-01-01

Background and purpose: In several previous studies, the C-X-C chemokine receptor (CXCR)2 antagonist 1-(2-bromo-phenyl)-3-(7-cyano-3H-benzotriazol-4-yl)-urea (SB265610) has been described as binding competitively with the endogenous agonist. This is in contrast to many other chemokine receptor antagonists, where the mechanism of antagonism has been described as allosteric. Experimental approach: To determine whether it displays a unique mechanism among the chemokine receptor antagonists, the mode of action of SB265610 was investigated at the CXCR2 receptor using radioligand and [35S]-GTPγS binding approaches in addition to chemotaxis of human neutrophils. Key results: In equilibrium saturation binding studies, SB265610 depressed the maximal binding of [125I]-interleukin-8 ([125I]-IL-8) without affecting the Kd. In contrast, IL-8 was unable to prevent binding of [3H]-SB265610. Kinetic binding experiments demonstrated that this was not an artefact of irreversible or slowly reversible binding. In functional experiments, SB265610 caused a rightward shift of the concentration-response curves to IL-8 and growth-related oncogene α, but also a reduction in maximal response elicited by each agonist. Fitting these data to an operational allosteric ternary complex model suggested that, once bound, SB265610 completely blocks receptor activation. SB265610 also inhibited basal [35S]-GTPγS binding in this preparation. Conclusions and implications: Taken together, these data suggest that SB265610 behaves as an allosteric inverse agonist at the CXCR2 receptor, binding at a region distinct from the agonist binding site to prevent receptor activation, possibly by interfering with G protein coupling. PMID:19422399

Thermoelectric Performance and Defect Chemistry in n-Type Zintl KGaSb 4

DOE PAGES

Ortiz, Brenden R.; Gorai, Prashun; Stevanovic, Vladan; ...

2017-05-08

The rise of high-throughput calculations has accelerated the discovery of promising classes of thermoelectric materials. In prior work, we identified the n-type Zintl pnictides as one such material class. To date, however, a lack of detailed defect calculations and chemical intuition has led the community to investigate p-type Zintls almost exclusively. Here, we investigate the synthesis, thermoelectric properties, and defect structure of the complex Zintl KGaSb 4. We find that KGaSb 4 is successfully doped n-type with Ba and has the potential for p-type doping with Zn. Our calculations reveal the fundamental defect structure in KGaSb 4 that enables n-typemore » and p-type doping. We find that Ba doped KGaSb4 exhibits high electronic mobility (~50 cm 2V -1s -1) and near minimum lattice thermal conductivity (<0.5 Wm -1K -1) at 400 °C. Samples doped with 1.5% Ba achieve zT > 0.9 at 400 °C, promising for a previously unstudied material. Here, we also briefly investigate the series of alloys between KGaSb 4 and KAlSb 4, finding that a full solid solution exists. Altogether our work reinforces motivation for the exploration of n-type Zintl materials, especially in tandem with high-throughput defect calculations to inform selection of effective dopants and systems amenable to n-type transport.« less

Thermoelectric Performance and Defect Chemistry in n-Type Zintl KGaSb 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz, Brenden R.; Gorai, Prashun; Stevanovic, Vladan

The rise of high-throughput calculations has accelerated the discovery of promising classes of thermoelectric materials. In prior work, we identified the n-type Zintl pnictides as one such material class. To date, however, a lack of detailed defect calculations and chemical intuition has led the community to investigate p-type Zintls almost exclusively. Here, we investigate the synthesis, thermoelectric properties, and defect structure of the complex Zintl KGaSb 4. We find that KGaSb 4 is successfully doped n-type with Ba and has the potential for p-type doping with Zn. Our calculations reveal the fundamental defect structure in KGaSb 4 that enables n-typemore » and p-type doping. We find that Ba doped KGaSb4 exhibits high electronic mobility (~50 cm 2V -1s -1) and near minimum lattice thermal conductivity (<0.5 Wm -1K -1) at 400 °C. Samples doped with 1.5% Ba achieve zT > 0.9 at 400 °C, promising for a previously unstudied material. Here, we also briefly investigate the series of alloys between KGaSb 4 and KAlSb 4, finding that a full solid solution exists. Altogether our work reinforces motivation for the exploration of n-type Zintl materials, especially in tandem with high-throughput defect calculations to inform selection of effective dopants and systems amenable to n-type transport.« less

Element-specific study of the temperature dependent magnetization of Co-Mn-Sb thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmalhorst, J.; Ebke, D.; Meinert, M.

Magnetron sputtered thin Co-Mn-Sb films were investigated with respect to their element-specific magnetic properties. Stoichiometric Co{sub 1}Mn{sub 1}Sb{sub 1} crystallized in the C1{sub b} structure has been predicted to be half-metallic and is therefore of interest for spintronics applications. It should show a characteristic antiferromagnetic coupling of the Mn and Co magnetic moments and a transition temperature T{sub C} of about 480K. Although the observed transition temperature of our 20nm thick Co{sub 32.4}Mn{sub 33.7}Sb{sub 33.8}, Co{sub 37.7}Mn{sub 34.1}Sb{sub 28.2} and Co{sub 43.2}Mn{sub 32.6}Sb{sub 24.2} films is in quite good agreement with the expected value, we found a ferromagnetic coupling ofmore » the Mn and Co magnetic moments which indicates that the films do not crystallize in the C1{sub b} structure and are probably not fully spin-polarized. The ratio of the Co and Mn moments does not change up to the transition temperature and the temperature dependence of the magnetic moments can be well described by the mean field theory.« less

Study of conformational changes and protein aggregation of bovine serum albumin in presence of Sb(III) and Sb(V).

PubMed

Verdugo, Marcelo; Ruiz Encinar, Jorge; Costa-Fernández, José Manuel; Menendez-Miranda, Mario; Bouzas-Ramos, Diego; Bravo, Manuel; Quiroz, Waldo

2017-01-01

Antimony is a metalloid that affects biological functions in humans due to a mechanism still not understood. There is no doubt that the toxicity and physicochemical properties of Sb are strongly related with its chemical state. In this paper, the interaction between Sb(III) and Sb(V) with bovine serum albumin (BSA) was investigated in vitro by fluorescence spectroscopy, and circular dichroism (CD) under simulated physiological conditions. Moreover, the coupling of the separation technique, asymmetric flow field-flow fractionation, with elemental mass spectrometry to understand the interaction of Sb(V) and Sb(III) with the BSA was also used. Our results showed a different behaviour of Sb(III) vs. Sb(V) regarding their effects on the interaction with the BSA. The effects in terms of protein aggregates and conformational changes were higher in the presence of Sb(III) compared to Sb(V) which may explain the differences in toxicity between both Sb species in vivo. Obtained results demonstrated the protective effect of GSH that modifies the degree of interaction between the Sb species with BSA. Interestingly, in our experiments it was possible to detect an interaction between BSA and Sb species, which may be related with the presence of labile complex between the Sb and a protein for the first time.

Robust ferroelectricity in two-dimensional SbN and BiP.

PubMed

Liu, Chang; Wan, Wenhui; Ma, Jie; Guo, Wei; Yao, Yugui

2018-05-03

Based on first-principles calculations, we discover two new two-dimensional (2D) ferroelectric materials SbN and BiP. Both of them are stable in a phosphorene-like structure and maintain their ferroelectricity above room temperature. Till date, SbN has the largest in-plane spontaneous polarization of about 7.81 × 10-10 C m-1 ever found in 2D ferroelectric materials, and it can retain its ferroelectricity until melting at about 1700 K. The spontaneous polarizations and switching barriers can easily be tuned by strains. Additionally, the ferroelectricity can still be maintained in their multilayers. These advantages make SbN and BiP promising candidate materials for future integrated ferroelectric devices.

Sb2O3/Ag/Sb2O3 Multilayer Transparent Conducting Films For Ultraviolet Organic Light-emitting Diode

PubMed Central

Song, Chunyan; Zhang, Nan; Lin, Jie; Guo, Xiaoyang; Liu, Xingyuan

2017-01-01

A novel UV transparent conducting films based on Sb2O3/Ag/Sb2O3 (SAS) structure, which were prepared by an electron-beam thermal evaporation at room temperature. This SAS exhibits excellent electrical, optical and stable properties. Especially for UV region, the SAS has high transmittance of 80% at 306 nm and 92% at 335 nm, meanwhile achieving low sheet resistance ( ≤ 10 Ω sq−1). The UV OLED based on the SAS show competitive device performance. The UV OLED obtains the peak of UV electroluminescence at 376 nm and shows a very high maximum EQE of 4.1% with the maximum output power density of 5.18 mW cm−2. These results indicate that the potential of SAS applications in deep UV transparent electrodes and large-scale flexible transparent electronics. PMID:28120888

Isolating GaSb membranes grown metamorphically on GaAs substrates using highly selective substrate removal etch processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavrova, Olga; Balakrishnan, Ganesh

2017-02-24

The etch rates of NH 4OH:H 2O 2 and C 6H 8O 7:H 2O 2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH 4OH:H 2O 2 solution has a greater etch rate differential for the GaSb/GaAs material system than C 6H 8O 7:H 2O 2 solution. The selectivity of NH 4OH:H 2O 2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11471 ± 1691 whereas that of C 6H 8O 7:H 2O 2 has been measured upmore » to 143 ± 2. The etch contrast has been verified by isolating 2 μm thick GaSb epi-layers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high-resolution X-Ray diffraction (HR-XRD) and atomic force microscopy (AFM).« less

Optimizing the Carrier Density and Thermoelectric Properties of Sb2Te3 Films by Using the Growth Temperature

NASA Astrophysics Data System (ADS)

Thiet, Duong Van; Quang, Nguyen Van; Hai, Nguyen Thi Minh; Huong, Nguyen Thi; Cho, Sunglae; Tuan, Duong Anh; Dung, Dang Duc; Tam, Tran Van

2018-04-01

In this work, we report on the structural and thermoelectric properties of Sb2Te3 films deposited on GaSb(111) substrates by using molecular beam epitaxy. The effects of the growth temperature on the microstructure and thermoelectric properties of the films were investigated. The results show that Sb2Te3 films grow on GaSb(111) along (00l) axis normal to the substrate and have a hexagonal structure with a layer-by-layer growth mode in growth temperature range from 200 to 250 °C while at 175 and 300 °C, the films show an island growth mode. Te and Sb2Te3 phases coexist at a growth temperature of 175 °C. The films exhibit a metallic behavior for growth temperatures below 250 °C and a semiconductor behavior at 300 °C. By changing growth temperature, we were able to vary the carrier density from 9.96×1018 to 4.55×1019 cm -3. At room temperature, the Seebeck coefficients are 110, 146, and 138 μV/K for growth temperatures of 175, 200 and 250 °C, respectively, and a large value of the power factor 61.67 μW/cm-K2 is achieved for the film grown at 250 °C.

Effects of annealing and additions on dynamic mechanical properties of SnSb quenched alloy

NASA Astrophysics Data System (ADS)

El-Bediwi, A. B.

2004-08-01

The elastic modulus, internal friction and stiffness values of quenched SnSb bearing alloy have been evaluated using the dynamic resonance technique. Annealing for 2 and 4 h at 120, 140 and 160degreesC caused variations in the elastic modulus. internal friction and stiffness values. This is due to structural changes in the SnSb matrix during isothermal annealing such as coarsening in the phases (Sn, Sb or intermetallic compounds), recrystallization and stress relief. In addition, adding a small amount (1 wt.%) of Cu or Ag improved the bearing mechanical properties of the SnSb bearing alloy. The SnSbCu1 alloy has the best bearing mechanical properties with thermo-mechanical stability for long time at high temperature.

Hydrazine solution processed Sb2S3, Sb2Se3 and Sb2(S1−xSex)3 film: molecular precursor identification, film fabrication and band gap tuning

PubMed Central

Yang, Bo; Xue, Ding-Jiang; Leng, Meiying; Zhong, Jie; Wang, Liang; Song, Huaibing; Zhou, Ying; Tang, Jiang

2015-01-01

Sb2(S1−xSex)3 (0 ≤ x ≤ 1) compounds have been proposed as promising light-absorbing materials for photovoltaic device applications. However, no systematic study on the synthesis and characterization of polycrystalline Sb2(S1−xSex)3 thin films has been reported. Here, using a hydrazine based solution process, single-phase Sb2(S1−xSex)3 films were successfully obtained. Through Raman spectroscopy, we have investigated the dissolution mechanism of Sb in hydrazine: 1) the reaction between Sb and S/Se yields [Sb4S7]2-/[Sb4Se7]2- ions within their respective solutions; 2) in the Sb-S-Se precursor solutions, Sb, S, and Se were mixed on a molecular level, facilitating the formation of highly uniform polycrystalline Sb2(S1−xSex)3 thin films at a relatively low temperature. UV-vis-NIR transmission spectroscopy revealed that the band gap of Sb2(S1−xSex)3 alloy films had a quadratical relationship with the Se concentration x and it followed the equation , where the bowing parameter was 0.118 eV. Our study provides a valuable guidance for the adjustment and optimization of the band gap in hydrazine solution processed Sb2(S1−xSex)3 alloy films for the future fabrication of improved photovoltaic devices. PMID:26042519

The Added Diagnostic Value of 18F-Fluorodihydroxyphenylalanine PET/CT in the Preoperative Work-Up of Small Bowel Neuroendocrine Tumors.

PubMed

Addeo, Pietro; Poncet, Gilles; Goichot, Bernard; Leclerc, Loic; Brigand, Cécile; Mutter, Didier; Romain, Benoit; Namer, Izzie-Jacques; Bachellier, Philippe; Imperiale, Alessio

2018-04-01

The precise localization of the primary tumor and/or the identification of multiple primary tumors improves the preoperative work-up in patients with small bowel (SB) neuroendocrine tumor (NET). The present study assesses the diagnostic value of 18 F-fluorodihydroxyphenylalanine ( 18 F-FDOPA) positron emission tomography/computed tomography (PET/CT) during the preoperative wok-up of SB NETs. Between January 2010 and June 2017, all consecutive patients with SB NETs undergoing preoperative 18 F-FDOPA PET/CT and successive resection were analyzed. Preoperative work-up included computed tomography (CT), somatostatin receptor scintigraphy (SRS), and 18 F-FDOPA PET/CT. Sensitivity and accuracy ratio for primary and multiple tumor detection were compared with data from surgery and pathology. There were 17 consecutive patients with SB NETs undergoing surgery. Nine patients (53%) had multiple tumors, 15 (88%) metastatic lymph nodes, 3 (18%) peritoneal carcinomatosis, and 9 patients (53%) liver metastases. A total of 70 SB NETs were found by pathology. Surgery identified the primary in 17/17 (100%) patients and recognized seven of 9 patients (78%) with multiple synchronous SB. Preoperatively, 18 F-FDOPA PET/CT displayed a statistically significant higher sensitivity for primary tumor localization (100 vs. 23.5 vs. 29.5%) and multiple tumor detection (78 vs. 22 vs. 11%) over SRS and CT. Compared with pathology, 18 F-FDOPA PET/CT displayed the highest accuracy ratio for number of tumor detected over CT and SRS (2.0 ± 2.2 vs. 0.4 ± 0.7 vs. 0.6 ± 1.5, p = 0.0003). 18 F-FDOPA PET/CT significantly increased the sensitivity and accuracy for primary and multiple SB NET identification. 18 F-FDOPA PET/CT should be included systematically in the preoperative work-up of SB NET.

Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao Jing; Liang Jingjing; Pan Yingli

Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en){sub 2}(dien)({eta}{sup 2}-SbSe{sub 4})] (Ln=Ce(1a), Nd(1b)), [Ln(en){sub 2}(dien)(SbSe{sub 4})] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)({mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4})]{sub {infinity}} (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)({eta}{sup 2}-SbSe{sub 4})] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe{sub 4}]{sup 3-} acts as a monodentate ligand mono-SbSe{sub 4}, a bidentate chelating ligand {eta}{sup 2}-SbSe{sub 4} or a tridentate bridging ligand {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} to the lanthanide(III) center depending on themore » Ln{sup 3+} ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E{sub g} between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: > Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. > The [SbSe{sub 4}]{sup 3-} anion acts as a mono-SbSe{sub 4}, a {eta}{sup 2}-SbSe{sub 4} or a {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} ligand to the Ln{sup 3+} ions. > The soft base ligand [SbSe{sub 4}]{sup 3-} can be controlled to coordinate to the Ln{sup 3+} ions with en+dien and en+trien as co-ligands.« less

Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

NASA Astrophysics Data System (ADS)

Yokoyama, Masafumi; Asakura, Yuji; Yokoyama, Haruki; Takenaka, Mitsuru; Takagi, Shinichi

2014-06-01

We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al2O3/GaSb MOS interface properties. The Al2O3/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (Dit) of ˜4.5 × 1013 cm-2 eV-1. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al2O3/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

Passivation of InSb surface for manufacturing infrared devices

NASA Astrophysics Data System (ADS)

Simchi, H.; Sareminia, Gh.; Shafiekhani, A.; Valizadeh, Gh.

2008-01-01

We studied the reduction of active surface states at the InSb/insulator interface by the reduction of hysteresis in C- V plots and by the performance of InSb diodes operated in photovoltaic mode. The InSb wafers were cleaned with CP4A etchant (HNO 3:CH 3COOH:HF:H 2O at 2:1:1:10). Then layers of 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 were deposited on the cleaned surfaced by plasma enhanced chemical vapor deposition (PECVD). After measuring the surface morphology by atomic force microscopy (AFM) the atomic percentage of each element in each compound (e.g. Si and O 2 in SiO 2 layer) was studied by energy-dispersive X-ray spectroscopy (EDX). By using photoemission spectroscopy (XPS), we showed that the SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers include Sb and/or SbO x and the Sb In antisite during deposition occurred and for this reason their etch rates differ from pure SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers. Then the gold metal was deposited on the samples and capacitance voltage measurement was made on the MIS samples. The results showed hysteresis free curves if the surface has been cleaned correctly. Finally by depositing the 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 on diode structure of InSb, the performance of diode in this case was compared with the anodic oxidation method. The results showed the performance of device is better than for the anodic oxidation method.

Characterization and identification of multiple constituents in Yinhuang granules by high-performance liquid chromatography with diode-array and time-of-flight mass spectrometry detection.

PubMed

Liu, E-Hu; Liu, Qun; Chu, Chu; Li, Ping

2011-10-01

A fast high-performance liquid chromatography (HPLC) method with diode-array detection (DAD) and time-of-flight mass spectrometry (TOF/MS) has been developed for the analysis of multi-constituent in Yinhuang granules, a well-known combined herbal remedy prepared from the extract mixtures of Flos Lonicerae and Radix Scutellariae. The fast HPLC analysis was performed on an Agilent ZorBax SB-C(18) column (4.6×50 mm, 1.8 μm) and 0.2% aqueous formic acid and acetonitrile was the optimum mobile phase for gradient elution in 17 min, which is five times faster than the performance of conventional columns packed with 5.0 μm particles. With various fragmentor voltages in TOF/MS, accurate mass measurements (<5 ppm error) for molecular ions and characteristic fragment ions represented reliable identification criteria for different constituents. A total of 28 compounds, including nine phenolic acids, three iridoid glycosides and nine saponins from Flos Lonicerae and seven flavonoids from Radix Scutellariae, were identified or tentatively characterized in the extract of Yinhuang granules. The established fast HPLC-DAD-TOF/MS method turns out to be useful and efficient for quality control of this commonly used Chinese herbal preparation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of bath temperature on structure, morphology and thermoelectric properties of CoSb{sub 3} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Suchitra, E-mail: suchitrayadav87@gmail.com; Pandya, Dinesh K.; Chaudhary, Sujeet

2016-05-23

CoSb{sub 3} thin films are deposited on conducting glass substrates (FTO) by electrodeposition at different bath temperatures (60°C, 70°C and 80°C) and the resulting influence of the bath temperature on the structure, morphology and electrical properties of films is investigated. X-ray diffraction confirms the formation of CoSb{sub 3} phase in the films. Scanning electron microscopy reveals that different morphologies ranging from branched nano-flakes to nano-needles evolve as bath temperature increases. It is concluded that a growth temperature of 80°C is suitable for producing CoSb{sub 3} films with such properties that show potential feasibility for thermoelectric applications.

High-temperature ferromagnetism in new n-type Fe-doped ferromagnetic semiconductor (In,Fe)Sb

NASA Astrophysics Data System (ADS)

Thanh Tu, Nguyen; Hai, Pham Nam; Anh, Le Duc; Tanaka, Masaaki

2018-06-01

Over the past two decades, intensive studies on various ferromagnetic semiconductor (FMS) materials have failed to realize reliable FMSs that have a high Curie temperature (T C > 300 K), good compatibility with semiconductor electronics, and characteristics superior to those of their nonmagnetic host semiconductors. Here, we demonstrate a new n-type Fe-doped narrow-gap III–V FMS, (In1‑ x ,Fe x )Sb. Its T C is unexpectedly high, reaching ∼335 K at a modest Fe concentration (x) of 16%. The anomalous Hall effect and magnetic circular dichroism (MCD) spectroscopy indicate that the high-temperature ferromagnetism in (In,Fe)Sb thin films is intrinsic and originates from the zinc-blende (In,Fe)Sb alloy semiconductor.

Metabolism of 18-methoxycoronaridine, an ibogaine analog, to 18-hydroxycoronaridine by genetically variable CYP2C19.

PubMed

Zhang, Wenjiang; Ramamoorthy, Yamini; Tyndale, Rachel F; Glick, Stanley D; Maisonneuve, Isabelle M; Kuehne, Martin E; Sellers, Edward M

2002-06-01

18-Methoxycoronaridine, a newly developed ibogaine analog, has been reported to decrease the self-administration of morphine, cocaine, ethanol, and nicotine. It has also been reported to attenuate naltrexone-precipitated signs of morphine withdrawal. In this study, three metabolites of 18-methoxycoronaridine (18-MC) were separated and identified by high-performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry (HPLC-ESI-MS-MS); the major metabolite was 18-hydroxycoronaridine (18-HC). The other two metabolites were elucidated as hydroxylated metabolites on the basis of their MS-MS spectra. Catalytic studies of 18-MC O-demethylase activity in human liver microsomes indicate that one high affinity enzyme is involved in this reaction (K(m) from 2.81 to 7.9 microM; V(max) from 0.045 to 0.29 nmol/mg/min). In cDNA-expressing microsomes, only CYP2C19 displayed significant 18-MC O-demethylase activity (K(m) 1.34 microM; V(max) 0.21 nmol/mg/min). S-Mephenytoin, a selective CYP2C19 inhibitor, inhibited 18-MC O-demethylation by 65% at a concentration of 2 times its K(I), and antibodies against rat 2C (human CYP2C8, 2C9, 2C19) inhibited 18-HC formation by 70%. Studies with other cytochrome P450 (P450)-selective chemical inhibitors and antibodies failed to demonstrate an appreciable role for other P450s in this reaction. In addition, in microsomes from five different human livers, 18-MC O-demethylation correlated with S-mephenytoin 4'hydroxylase activity but not with other P450 probe reactions. These data indicate that 18-HC formation is the predominant pathway of 18-MC metabolism in vitro in human liver microsomes and that this metabolic pathway is primarily catalyzed by the polymorphic CYP2C19. The apparent selectivity of this pathway for CYP2C19 suggests 18-MC as a potentially useful probe of CYP2C19 activity in vitro and in vivo.

GPU-powered model analysis with PySB/cupSODA.

PubMed

Harris, Leonard A; Nobile, Marco S; Pino, James C; Lubbock, Alexander L R; Besozzi, Daniela; Mauri, Giancarlo; Cazzaniga, Paolo; Lopez, Carlos F

2017-11-01

A major barrier to the practical utilization of large, complex models of biochemical systems is the lack of open-source computational tools to evaluate model behaviors over high-dimensional parameter spaces. This is due to the high computational expense of performing thousands to millions of model simulations required for statistical analysis. To address this need, we have implemented a user-friendly interface between cupSODA, a GPU-powered kinetic simulator, and PySB, a Python-based modeling and simulation framework. For three example models of varying size, we show that for large numbers of simulations PySB/cupSODA achieves order-of-magnitude speedups relative to a CPU-based ordinary differential equation integrator. The PySB/cupSODA interface has been integrated into the PySB modeling framework (version 1.4.0), which can be installed from the Python Package Index (PyPI) using a Python package manager such as pip. cupSODA source code and precompiled binaries (Linux, Mac OS/X, Windows) are available at github.com/aresio/cupSODA (requires an Nvidia GPU; developer.nvidia.com/cuda-gpus). Additional information about PySB is available at pysb.org. paolo.cazzaniga@unibg.it or c.lopez@vanderbilt.edu. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

Enthalpy of mixing of liquid systems for lead free soldering: Ni-Sb-Sn system.

PubMed

Elmahfoudi, A; Fürtauer, S; Sabbar, A; Flandorfer, H

2012-04-20

The partial and integral enthalpies of mixing of liquid ternary Ni-Sb-Sn alloys were determined along five sections x Sb / x Sn  = 3:1, x Sb / x Sn  = 1:1, x Sb / x Sn  = 1:3, x Ni / x Sn  = 1:4, and x Ni / x Sb  = 1:4 at 1000 °C in a large compositional range using drop calorimetry techniques. The mixing enthalpy of Ni-Sb alloys was determined at the same temperature and described by a Redlich-Kister polynomial. The other binary data were carefully evaluated from literature values. Our measured ternary data were fitted on the basis of an extended Redlich-Kister-Muggianu model for substitutional solutions. Additionally, a comparison of these results to the extrapolation model of Toop is given. The entire ternary system shows exothermic values of Δ mix H ranging from approx. -1300 J/mol, the minimum in the Sb-Sn binary system down to approx. -24,500 J/mol towards Ni-Sb. No significant ternary interaction could be deduced from our data.

Type-II InAs/GaSb (InAsSb) superlattices for interband cascade midwavelength detectors

NASA Astrophysics Data System (ADS)

Hackiewicz, Klaudia; Martyniuk, Piotr

2018-02-01

Type-II superlattice (T2SL) interband cascade infrared detectors (IB CIDs) proved to be a promising candidate for short response time devices operating in room and higher temperatures. The current status of the higher operating temperature (HOT) T2SLs InAs/GaSb and InAs/InAsSb IB CID is presented. We compare both materials with HgCdTe alloy, which is widely described in literature. The detectivity of midwave infrared (MWIR) T2SLs InAs/GaSb and InAs/InAsSb based IB CID has been demonstrated up to 380 K.

The OsO(3)F(+) and mu-F(OsO(3)F)(2)(+) cations: their syntheses and study by Raman and (19)F NMR spectroscopy and electron structure calculations and X-ray crystal structures of [OsO(3)F][PnF(6)] (Pn = As, Sb), [OsO(3)F][HF](2)[AsF(6)], [OsO(3)F][HF][SbF(6)], and [OsO(3)F][Sb(3)F(16)].

PubMed

Gerken, Michael; Dixon, David A; Schrobilgen, Gary J

2002-01-28

The fluoride ion donor properties of OsO(3)F(2) have been investigated. The salts [OsO(3)F][AsF(6)], [OsO(3)F][HF](2)[AsF(6)], mu-F(OsO(3)F)(2)[AsF(6)], [OsO(3)F][HF](2)[SbF(6)], and [OsO(3)F][HF][SbF(6)] have been prepared by reaction of OsO(3)F(2) with AsF(5) and SbF(5) in HF solvent and have been characterized in the solid state by Raman spectroscopy. The single-crystal X-ray diffraction studies of [OsO(3)F][AsF(6)] (P2(1)/n, a = 7.0001(11) A, c = 8.8629(13) A, beta = 92.270(7) degrees, Z = 4, and R(1) = 0.0401 at -126 degrees C), [OsO(3)F][SbF(6)] (P2(1)/c, a = 5.4772(14) A, b = 10.115(3) A, c = 12.234(3) A, beta = 99.321(5) degrees, Z = 4, and R(1) = 0.0325 at -173 degrees C), [OsO(3)F][HF](2)[AsF(6)] (P2(1)/n, a = 5.1491(9) A, b = 8.129(2) A, c = 19.636(7) A, beta = 95.099(7) degrees, Z = 4, and R(1) = 0.0348 at -117 degrees C), and [OsO(3)F][HF][SbF(6)] (Pc, a = 5.244(4) A, b = 9.646(6) A, c = 15.269(10) A, beta = 97.154(13) degrees, Z = 4, and R(1) = 0.0558 at -133 degrees C) have shown that the OsO(3)F(+) cations exhibit strong contacts to the anions and HF solvent molecules giving rise to cyclic, dimeric structures in which the osmium atoms have coordination numbers of 6. The reaction of OsO(3)F(2) with neat SbF(5) yielded [OsO(3)F][Sb(3)F(16)], which has been characterized by (19)F NMR spectroscopy in SbF(5) and SO(2)ClF solvents and by Raman spectroscopy and single-crystal X-ray diffraction in the solid state (P4(1)m, a = 10.076(6) A, c = 7.585(8) A, Z = 2, and R(1) = 0.0858 at -113 degrees C). The weak fluoride ion basicity of the Sb(3)F(16)(-) anion resulted in an OsO(3)F(+) cation (C(3)(v) point symmetry) that is well isolated from the anion and in which the osmium is four-coordinate. The geometrical parameters and vibrational frequencies of OsO(3)F(+), ReO(3)F, mu-F(OsO(3)F)(2)(+), (FO(3)Os--FPnF(5))(2), and (FO(3)Os--(HF)(2)--FPnF(5))(2) (Pn = As, Sb) have been calculated using density functional theory methods.

Low temperature grown GaNAsSb: A promising material for photoconductive switch application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, K. H.; Yoon, S. F.; Wicaksono, S.

2013-09-09

We report a photoconductive switch using low temperature grown GaNAsSb as the active material. The GaNAsSb layer was grown at 200 °C by molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and a valved antimony cracker source. The low temperature growth of the GaNAsSb layer increased the dark resistivity of the switch and shortened the carrier lifetime. The switch exhibited a dark resistivity of 10{sup 7} Ω cm, a photo-absorption of up to 2.1 μm, and a carrier lifetime of ∼1.3 ps. These results strongly support the suitability of low temperature grown GaNAsSb in the photoconductivemore » switch application.« less

Solvothermal synthesis of a new 3-D mixed-metal sulfide framework, (H1.33tren)[In2.67Sb1.33S8]·tren

NASA Astrophysics Data System (ADS)

Lampkin, John D.; Powell, Anthony V.; Chippindale, Ann M.

2016-11-01

A new indium(III) antimony(V) sulfide, (H1.33tren)[In2.67Sb1.33S8]·tren, has been prepared solvothermally at 433 K. The compound crystallises in the tetragonal space group I-42d (lattice parameters, a=12.6248(5) and c=19.4387(18) Å at 150 K) and contains adamantane-like T2 supertetrahedral units comprised of corner-sharing InS45- and SbS43- tetrahedra. The adamantane-like units are then linked through sulfur vertices to generate an open, 3-D framework structure containing large pores in which neutral, protonated tren (tris(2-aminoethylene)amine) molecules reside. The presence of the organic components was confirmed by solid-state 13C NMR (10 kHz), combustion and thermogravimetric analysis. The band gap, obtained from UV-vis diffuse reflectance measurements, is 2.7(2) eV. Stirring with either water or alkali-metal salt solution leads to removal of the neutral tren molecules and an 9% reduction in unit-cell volume on formation of (H1.33tren)[In2.67Sb1.33S8]·(H2O)4.

Lattice Dynamical, Elastic and Thermodynamical Properties of III-V Semiconductor AlSb, GaSb and Their Mixed Semiconductor Ga_{1-x}AlxSb

NASA Astrophysics Data System (ADS)

Kushwaha, A. K.

2017-07-01

A proposed eleven-parameter three-body shell model is used to study the lattice dynamical properties such as phonon dispersion relations along high symmetry directions, phonon density of states, variation of specific heat and Debye characteristic temperature with absolute temperature, elastic constants and related properties for III-V semiconductor AlSb, GaSb and their mixed semiconductor Ga_{1-x}AlxSb having zinc-blende structure. We found an overall good agreement with the available experimental and theoretical results available in the literature.

Bi flux-dependent MBE growth of GaSbBi alloys

DOE PAGES

Rajpalke, M. K.; Linhart, W. M.; Yu, K. M.; ...

2015-03-05

The incorporation of Bi in GaSb 1-xBi x alloys grown by molecular beam epitaxy is investigated as a function of Bi flux at fixed growth temperature (275 °C) and growth rate (1 μm h⁻¹). The Bi content is found to vary proportionally with Bi flux with Bi contents, as measured by Rutherford backscattering, in the range 0 < x ≤ 4.5%. The GaSbBi samples grown at the lowest Bi fluxes have smooth surfaces free of metallic droplets. The higher Bi flux samples have surface Bi droplets. The room temperature band gap of the GaSbBi epitaxial layers determined from optical absorptionmore » decreases linearly with increasing Bi content with a reduction of ~32 meV/%Bi.« less

The effects of the selective 5-HT(2C) receptor antagonist SB 242084 on learned helplessness in male Fischer 344 rats.

PubMed

Strong, Paul V; Greenwood, Benjamin N; Fleshner, Monika

2009-05-01

Rats exposed to an uncontrollable stressor demonstrate a constellation of behaviors such as exaggerated freezing and deficits in shuttle box escape learning. These behaviors in rats have been called learned helplessness and have been argued to model human stress-related mood disorders. Learned helplessness is thought to be caused by hyperactivation of serotonin (5-HT) neurons in the dorsal raphe nucleus (DRN) and a subsequent exaggerated release of 5-HT in DRN projection sites. Blocking 5-HT(2C) receptors in the face of an increase in serotonin can alleviate anxiety behaviors in some animal models. However, specific 5-HT receptor subtypes involved in learned helplessness remain unknown. The current experiments tested the hypothesis that 5-HT(2C) receptor activation is necessary and sufficient for the expression of learned helplessness. The selective 5-HT(2C) receptor antagonist SB 242084 (1.0 mg/kg) administered i.p. to adult male Fischer 344 rats prior to shuttle box behavioral testing, but not before stress, blocked stress-induced deficits in escape learning but had no effect on the exaggerated shock-elicited freezing. The selective 5-HT(2C) receptor agonist CP-809101 was sufficient to produce learned helplessness-like behaviors in the absence of prior stress and these effects were blocked by pretreatment with SB 242084. Results implicate the 5-HT(2C) receptor subtype in mediating the shuttle box escape deficits produced by exposure to uncontrollable stress and suggest that different postsynaptic 5-HT receptor subtypes underlie the different learned helplessness behaviors.

Undercooling and solidification behavior in the InSb-Sb system. M.S. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Graves, J. A.

1985-01-01

Use of the droplet emulsion technique has been successful in studying the undercooling and crystallization behavior of Sb, InSb, and an InSb-Sb eutectic alloy. Both droplet size and imposed cooling rate were influential in controlling the extent of liquid undercooling. The droplet surface coating was of significant importance in determining the resultant solidification product structure through its effect on nucleation kinetics. The maximum undercooling for pure Sb was extended from 0.08 to 0.23 T sub m. While simple crushing techniques provided a dramatic increase in droplet undercooling over the bulk material, emulsification treatments both enhanced this undercooling and allowed successful formation of a metastable simple cubic Sb phase. This phase was stable to temperatures approaching the melting point. The simple cubic phase was detected in droplet samples processed using DTA, air and water quenching, and drop tube processing under a helium gas atmosphere. A deviation in the InSb parent ingot composition limited interpretation of the line compound results, however, emulsification techniques extended the undercooling of this material to 0.17 T sub L and provided a stable, protective surface coating for the droplets. Emulsification of the eutectic alloy was effective at producing various levels of undercooling from 0.1 to 0.2 T sub E. Microstructural examination revealed a normal-type eutectic structure in the undercooled droplets indicating that solidification occurred within the coupled zone and that this zone is somewhat symmetric about the eutectic composition.

Sb 121 , 123 nuclear quadrupole resonance as a microscopic probe in the Te-doped correlated semimetal FeSb 2 : Emergence of electronic Griffith phase, magnetism, and metallic behavior

DOE PAGES

Gippius, A. A.; Zhurenko, S. V.; Hu, R.; ...

2018-02-12

121,123Sb nuclear quadrupole resonance (NQR) was applied to Fe(Sb 1-xTe x) 2 in the low doping regime (x = 0 , 0.01, and 0.05) as a microscopic zero field probe to study the evolution of 3d magnetism and the emergence of metallic behavior. Whereas the NQR spectra itself reflects the degree of local disorder via the width of the individual NQR lines, the spin lattice relaxation rate (SLRR) 1/T 1 (T) probes the fluctuations at the Sb site. The fluctuations originate either from conduction electrons or from magnetic moments. In contrast to the semimetal FeSb 2 with a clear signaturemore » of the charge and spin gap formation in 1/T 1(T)T[~exp/(Δk BT)] , the 1% Te-doped system exhibits almost metallic conductivity and the SLRR nicely confirms that the gap is almost filled. A weak divergence of the SLRR coefficient 1/T 1(T)T ~ T -n ~ T -0.2 points towards the presence of electronic correlations towards low temperatures. This is supported by the electronic specific heat coefficient γ = (C el/T) showing a power-law divergence γ (T) ~ T -m ~ (1/T 1T) 1/2 ~ T -n/2 ~ C el/T which is expected in the renormalized Landau Fermi liquid theory for correlated electrons. In contrast to that the 5% Te-doped sample exhibits a much larger divergence in the SLRR coefficient showing 1/T 1(T)T ~ T -0.72 . According to the specific heat divergence a power law with n = 2 m = 0.56 is expected for the SLRR. This dissimilarity originates from admixed critical magnetic fluctuations in the vicinity of antiferromagnetic long range order with 1/T 1(T)T ~ T -3/4 behavior. Furthermore Te-doped FeSb 2 as a disordered paramagnetic metal might be a platform for the electronic Griffith phase scenario. NQR evidences a substantial asymmetric broadening of the 121,123Sb NQR spectrum for the 5% sample. Lastly, this has a predominant electronic origin in agreement with the electronic Griffith phase and stems probably from an enhanced Sb-Te bond polarization and electronic density shift towards the Te

Sb 121 , 123 nuclear quadrupole resonance as a microscopic probe in the Te-doped correlated semimetal FeSb 2 : Emergence of electronic Griffith phase, magnetism, and metallic behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gippius, A. A.; Zhurenko, S. V.; Hu, R.

121,123Sb nuclear quadrupole resonance (NQR) was applied to Fe(Sb 1-xTe x) 2 in the low doping regime (x = 0 , 0.01, and 0.05) as a microscopic zero field probe to study the evolution of 3d magnetism and the emergence of metallic behavior. Whereas the NQR spectra itself reflects the degree of local disorder via the width of the individual NQR lines, the spin lattice relaxation rate (SLRR) 1/T 1 (T) probes the fluctuations at the Sb site. The fluctuations originate either from conduction electrons or from magnetic moments. In contrast to the semimetal FeSb 2 with a clear signaturemore » of the charge and spin gap formation in 1/T 1(T)T[~exp/(Δk BT)] , the 1% Te-doped system exhibits almost metallic conductivity and the SLRR nicely confirms that the gap is almost filled. A weak divergence of the SLRR coefficient 1/T 1(T)T ~ T -n ~ T -0.2 points towards the presence of electronic correlations towards low temperatures. This is supported by the electronic specific heat coefficient γ = (C el/T) showing a power-law divergence γ (T) ~ T -m ~ (1/T 1T) 1/2 ~ T -n/2 ~ C el/T which is expected in the renormalized Landau Fermi liquid theory for correlated electrons. In contrast to that the 5% Te-doped sample exhibits a much larger divergence in the SLRR coefficient showing 1/T 1(T)T ~ T -0.72 . According to the specific heat divergence a power law with n = 2 m = 0.56 is expected for the SLRR. This dissimilarity originates from admixed critical magnetic fluctuations in the vicinity of antiferromagnetic long range order with 1/T 1(T)T ~ T -3/4 behavior. Furthermore Te-doped FeSb 2 as a disordered paramagnetic metal might be a platform for the electronic Griffith phase scenario. NQR evidences a substantial asymmetric broadening of the 121,123Sb NQR spectrum for the 5% sample. Lastly, this has a predominant electronic origin in agreement with the electronic Griffith phase and stems probably from an enhanced Sb-Te bond polarization and electronic density shift towards the Te

Canted antiferromagnetism in phase-pure CuMnSb

NASA Astrophysics Data System (ADS)

Regnat, A.; Bauer, A.; Senyshyn, A.; Meven, M.; Hradil, K.; Jorba, P.; Nemkovski, K.; Pedersen, B.; Georgii, R.; Gottlieb-Schönmeyer, S.; Pfleiderer, C.

2018-05-01

We report the low-temperature properties of phase-pure single crystals of the half-Heusler compound CuMnSb grown by means of optical float zoning. The magnetization, specific heat, electrical resistivity, and Hall effect of our single crystals exhibit an antiferromagnetic transition at TN=55 K and a second anomaly at a temperature T*≈34 K. Powder and single-crystal neutron diffraction establish an ordered magnetic moment of (3.9 ±0.1 ) μB/f .u . , consistent with the effective moment inferred from the Curie-Weiss dependence of the susceptibility. Below TN, the Mn sublattice displays commensurate type-II antiferromagnetic order with propagation vectors and magnetic moments along <111 > (magnetic space group R [I ]3 c ). Surprisingly, below T*, the moments tilt away from <111 > by a finite angle δ ≈11∘ , forming a canted antiferromagnetic structure without uniform magnetization consistent with magnetic space group C [B ]c . Our results establish that type-II antiferromagnetism is not the zero-temperature magnetic ground state of CuMnSb as may be expected of the face-centered cubic Mn sublattice.

GaSb/AlGaSb VCSEL structures and microcavities in the 1.5 μm wavelength range

NASA Astrophysics Data System (ADS)

Koeth, J.; Dietrich, R.; Reithmaier, J. P.; Forchel, A.

Vertical cavity surface emitting laser structures for 1.5 μm wavelength applications were realized by growing AlSb/AlGaSb Bragg mirrors on GaAs substrates with solid source molecular beam epitaxy. Due to the high refractive index contrast between GaSb and AlSb high quality resonators can be made by only 15 layer pairs for each Bragg mirror. Laser operation could be demonstrated by optical pumping with threshold excitation densities of about 500 W/cm2. In laterally deeply etched microcavities with diameters of 5 μm a clear discretization of the optical modes was observed. The lateral confinement effects are compared with results of AlAs/GaAs microcavities designed for 0.9 μm emission wavelength. Due to the longer wavelength a stronger confinement effect can be achieved in AlSb/AlGaSb microcavities for the same lateral dimensions.

Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yokoyama, Masafumi, E-mail: yokoyama@mosfet.t.u-tokyo.ac.jp; Takenaka, Mitsuru; Takagi, Shinichi

We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The Al{sub 2}O{sub 3}/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (D{sub it}) of ∼4.5 × 10{sup 13 }cm{sup −2} eV{sup −1}. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situmore » ALD process to avoid the high-temperature-induced degradations.« less

The glass transition, crystallization and melting in Au-Pb-Sb alloys

NASA Technical Reports Server (NTRS)

Lee, M. C.; Allen, J. L.; Fecht, H. J.; Perepezko, J. H.; Ohsaka, K.

1988-01-01

The glass transition, crystallization and melting of Au(55)Pb(22.5)Sb(22.5) alloys have been studied by differential scanning calorimetry DSC. Crystallization on heating above the glass transition temperature Tg (45 C) begins at 64 C. Further crystallization events are observed at 172 C and 205 C. These events were found to correspond to the formation of the intermetallic compounds AuSb2, Au2Pb, and possibly AuPb2, respectively. Isothermal DSC scans of the glassy alloy above Tg were used to monitor the kinetics of crystallization. The solidification behavior and heat capacity in the glass-forming composition range were determined with droplet samples. An undercooling level of 0.3T(L) below the liquidus temperature T(L) was achieved, resulting in crystallization of different stable and metastable phases. The heat capacity C(P) of the undercooled liquid was measured over an undercooling range of 145 C.

Improvement of antimony sulfide photo absorber performance by interface modification in Sb2S3-ZnO hybrid nanostructures

NASA Astrophysics Data System (ADS)

Ali, Asad; Hasanain, Syed Khurshid; Ali, Tahir; Sultan, Muhammad

2017-03-01

Metal-oxide chalcogenide nanostructures as part of hybrid systems are very important for photovoltaic and optoelectronic applications. It is however known that the various interfaces within the hybrid structures play a crucial role in limiting the efficiency of these devices. Here we report on the improvement of Sb2S3 structure through modification of interface between Zn-oxide nanostructures and chalcogenides. ZnO nanorods were grown on fluorine doped tin oxide (FTO) substrate by chemical bath deposition (CBD) method. X-ray diffraction (XRD) and SEM analysis confirmed the single phase wurtzite structure and c-axis orientation of the ZnO nanorod arrays. Antimony tri-sulfide (Sb2S3) was deposited on ZnO nanords by CBD and subsequently annealed at 300 °C in argon environment for 30 min. XRD and the XPS analysis of ZnO-Sb2S3 system showed the dominant presence of Sb2O3 rather than Sb2S3. Since oxidation of Sb2S3 is understood to proceed mainly from the ZnO-Sb2S3 interface, a ZnS interlayer was introduced between ZnO nanorods and Sb2S3 by chemical route. The subsequent structural and optical properties of the ZnO-ZnS-Sb2S3 system are analyzed in detail. The introduction of sulfide interlayer prevents the oxidation of Sb2S3 which is evident from reduced oxide phase in Sb2S3. Significant improvement in the structural and optical properties of Sb2S3 are reported as compared to the parent ZnO-Sb2S3 system. This gain in the optical properties of hybrid ZnO-ZnS-Sb2S3 nanostructures is explained as being related to successful prevention of Sb2O3 formation at the Sb-ZnO interface and stabilization of the desired Sb2S3.

In-plane optical anisotropy of InAs/GaSb superlattices with alternate interfaces

PubMed Central

2013-01-01

The in-plane optical anisotropy (IPOA) in InAs/GaSb superlattices has been studied by reflectance difference spectroscopy (RDS) at different temperatures ranging from 80 to 300 K. We introduce alternate GaAs- and InSb-like interfaces (IFs), which cause the symmetry reduced from D2d to C2v. IPOA has been observed in the (001) plane along [110] and [11¯0] axes. RDS measurement results show strong anisotropy resonance near critical point (CP) energies of InAs and GaSb. The energy positions show red shift and RDS intensity decreases with the increasing temperature. For the superlattice sample with the thicker InSb-like IFs, energy positions show red shift, and the spectra exhibit stronger IPOA. The excitonic effect is clearly observed by RDS at low temperatures. It demonstrates that biaxial strain results in the shift of the CP energies and IPOA is enhanced by the further localization of the carriers in InSb-like IFs. PMID:23799946

FAST TRACK COMMUNICATION: Emission wavelength extension of mid-infrared InAsSb/InP nanostructures using InGaAsSb sandwich layers

NASA Astrophysics Data System (ADS)

Lei, W.; Tan, H. H.; Jagadish, C.

2010-08-01

This paper presents a study on the emission wavelength extension of InAsSb nanostructures using InGaAsSb sandwich layers. Due to the reduced lattice mismatch between InAsSb nanostructure layer and buffer/capping layer, the introduction of InGaAsSb sandwich layers leads to larger island size, reduced compressive strain and lower confinement barrier for InAsSb nanostructures, thus resulting in a longer emission wavelength. For InGaAsSb sandwich layers with nominal Sb concentration higher than 10%, type II band alignment is observed for the InAsSb/InGaAsSb heterostructure, which also contributes to the extension of emission wavelength. The InGaAsSb sandwich layers provide an effective approach to extend the emission wavelength of InAsSb nanostructures well beyond 2 µm, which is very useful for device applications in the mid-infrared region.

Structure and magnetic properties of L n MnSbO ( L n = La and Ce)

DOE PAGES

Zhang, Qiang; Kumar, C. M. N.; Tian, Wei; ...

2016-03-11

Here, a neutron powder diffraction (NPD) study of LnMnSbO (Ln = La or Ce) reveals differences between the magnetic ground state of the two compounds due to the strong Ce-Mn coupling compared to La-Mn. The two compounds adopt the P4/nmm space group down to 2 K, and whereas magnetization measurements do not show obvious anomaly at high temperatures, NPD reveals a C-type antiferromagnetic (AFM) order below T N = 255K for LaMnSbO and 240 K for CeMnSbO. While the magnetic structure of LaMnSbO is preserved to base temperature, a sharp transition at T SR = 4.5K is observed in CeMnSbOmore » due to a spin-reorientation (SR) transition of the Mn 2+ magnetic moments from pointing along the c axis to the ab plane. The SR transition in CeMnSbO is accompanied by a simultaneous long-range AFM ordering of the Ce moments, which indicates that the Mn SR transition is driven by the Ce-Mn coupling. The ordered moments are found to be somewhat smaller than those expected for Mn 2+ (S = 5/2) in insulators, but large enough to suggest that these compounds belong to the class of local-moment antiferromagnets. The lower T N found in these two compounds compared to the As-based counterparts (T N = 317 for LaMnAsO, T N = 347K for CeMnAsO) indicates that the Mn-Pn (Pn=As or Sb) hybridization that mediates the superexchange Mn-Pn-Mn coupling is weaker for the Sb-based compounds.« less

Controlling compositional homogeneity and crystalline orientation in Bi 0.8 Sb 0.2 thermoelectric thin films [Control of composition and crystallinity in Bi 0.8Sb 0.2 thermoelectric thin films].

DOE PAGES

Rochford, C.; Medlin, D. L.; Erickson, K. J.; ...

2015-12-01

Controlling alloy composition, crystalline quality, and crystal orientation is necessary to achieve high thermoelectric performance in Bi 1-xSb x thin films. These microstructural attributes are demonstrated in this letter via co-sputter deposition of Bi and Sb metals on Si/SiO 2 substrates followed by ex-situ post anneals ranging from 200 – 300 °C in forming gas with rapid cooling to achieve orientation along the trigonal axis. We show with cross-sectional transmission electron microscopy and energy-dispersive X-ray spectrometry that 50 – 95% of the Sb segregates at the surface upon exposure to air during transfer. This then forms a nanocrystalline Sb 2Omore » 3 layer upon annealing, leaving the bulk of the film primarily Bi metal which is a poor thermoelectric material. We demonstrate a SiN capping technique to eliminate Sb segregation and preserve a uniform composition throughout the thickness of the film. Given that the Bi 1-xSb x solid solution melting point depends on the Sb content, the SiN cap allows one to carefully approach but not exceed the melting point during annealing. This leads to the strong orientation along the trigonal axis and high crystalline quality desired for thermoelectric applications.« less

Installation Restoration Program Stage 2-1 Remedial Investigation. Beale Air Force Base, Marysville, California. Volume 2. Appendix A

DTIC Science & Technology

1991-03-29

S) A-927 BAFB-0427 22159-4 13-C-2SB (S) A-929 BAFB- 0428 22159-5 13-C-2SB (S) A-930 BAFB-0256 21872-11 13-C-2SB (S) A-931 BAFB-0429 22159-6 13-C-2SB (S...16 18-C-19SS (S) A-1305 BAFB-0021 21621-17 18-C-20SS (S) A- 1307 BAFB-0022 21621-18 18-C-20SS (S) A-1309 BAFB-0024 21621-20 18-C-21SS (S) A-1311 BAFB...ASA#9) 21.0 N/A MERCURY (SW7471) (Resampled for this analysis. See BAFB-0427 and BAFB- 0428 ) TFH-DIESEL (TFH-DIESEL) ə.3 1.3 mg/kg. (non-detect) TFH

Evaluation in Monkey of Two Candidate PET Radioligands, [11C]RX-1 and [18F]RX-2, for Imaging Brain 5-HT4 Receptors

PubMed Central

LOHITH, TALAKAD G.; XU, RONG; TSUJIKAWA, TETSUYA; MORSE, CHERYL L.; ANDERSON, KACEY B.; GLADDING, ROBERT L.; ZOGHBI, SAMI S.; FUJITA, MASAHIRO; INNIS, ROBERT B.; PIKE, VICTOR W.

2014-01-01

The serotonin subtype-4 (5-HT4) receptor, which is known to be involved physiologically in learning and memory, and pathologically in Alzheimer’s disease, anxiety and other neuropsychiatric disorders – has few radioligands readily available for imaging in vivo. We have previously reported two novel 5-HT4 receptor radioligands, namely [methoxy-11C](1-butylpiperidin-4-yl)methyl 4-amino-3-methoxybenzoate; [11C]RX-1) and the [18F]3-fluoromethoxy analog ([18F]RX-2), and in this study we evaluated them by PET in rhesus monkey. Brain scans were performed at baseline, receptor preblock or displacement conditions using SB 207710, a 5-HT4 receptor antagonist, on the same day for [11C]RX-1 and on different days for [18F]RX-2. Specific-to-nondisplaceable ratio (BPND) was measured with the simplified reference tissue model from all baseline scans. To determine specific binding, total distribution volume (VT) was also measured in some monkeys by radiometabolite-corrected arterial input function after ex vivo inhibition of esterases from baseline and blocked scans. Both radioligands showed moderate to high peak brain uptake of radioactivity (2–6 SUV). Regional BPND values were in the rank order of known 5-HT4 receptor distribution with a trend for higher BPND values from [18F]RX-2. One-tissue compartmental model provided good fits with well identified VT values for both radioligands. In the highest 5-HT4 receptor density region, striatum, 50–60% of total binding was specific. The VT in receptor-poor cerebellum reached stable values by about 60 min for both radioligands indicating little influence of radiometabolites on brain signal. In conclusion, both [11C]RX-1 and [18F]RX-2 showed positive attributes for PET imaging of brain 5-HT4 receptors, validating the radioligand design strategy. PMID:25088028

Treatment of air pollution control residues with iron rich waste sulfuric acid: does it work for antimony (Sb)?

PubMed

Okkenhaug, Gudny; Breedveld, Gijs D; Kirkeng, Terje; Lægreid, Marit; Mæhlum, Trond; Mulder, Jan

2013-03-15

Antimony (Sb) in air pollution control (APC) residues from municipal solid waste incineration has gained increased focus due to strict Sb leaching limits set by the EU landfill directive. Here we study the chemical speciation and solubility of Sb at the APC treatment facility NOAH Langøya (Norway), where iron (Fe)-rich sulfuric acid (∼3.6M, 2.3% Fe(II)), a waste product from the industrial extraction of ilmenite, is used for neutralization. Antimony in water extracts of untreated APC residues occurred exclusively as pentavalent antimonate, even at low pH and Eh values. The Sb solubility increased substantially at pH<10, possibly due to the dissolution of ettringite (at alkaline pH) or calcium (Ca)-antimonate. Treated APC residues, stored anoxically in the laboratory, simulating the conditions at the NOAH Langøya landfill, gave rise to decreasing concentrations of Sb in porewater, occurring exclusively as Sb(V). Concentrations of Sb decreased from 87-918μgL(-1) (day 3) to 18-69μgL(-1) (day 600). We hypothesize that an initial sorption of Sb to Fe(II)-Fe(III) hydroxides (green rust) and eventually precipitation of Ca- and Fe-antimonates (tripuhyite; FeSbO4) occurred. We conclude that Fe-rich, sulfuric acid waste is efficient to immobilize Sb in APC residues from waste incineration. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral characterisation of aperiodic normal-incidence Sb/B4C multilayer mirrors for the λ < 124 Å range

NASA Astrophysics Data System (ADS)

Vishnyakov, E. A.; Kopylets, I. A.; Kondratenko, V. V.; Kolesnikov, A. O.; Pirozhkov, A. S.; Ragozin, E. N.; Shatokhin, A. N.

2018-03-01

Three broadband aperiodic Sb/B4C multilayer mirrors were synthesised for the purposes of soft X-ray optics and spectroscopy in the wavelength range beyond the L-edge of Si (λ < 124 Å), and their reflection spectra were measured. The multilayer structures were optimised for maximum uniform reflectivity in the ranges 100–120 Å, 95–105 Å and 90–100 Å. The reflection spectra were recorded using a laboratory laser-plasma radiation source and an electronic detector with a 2D spatial resolution (a CCD matrix with 13 × 13 μm sized pixels). The experimental spectra are compared with theoretical calculations. The effect of lower antimony and B4C layer densities on the reflection spectra is discussed.

Approaches to characterise chromatographic column performance based on global parameters accounting for peak broadening and skewness.

PubMed

Baeza-Baeza, J J; Pous-Torres, S; Torres-Lapasió, J R; García-Alvarez-Coque, M C

2010-04-02

Peak broadening and skewness are fundamental parameters in chromatography, since they affect the resolution capability of a chromatographic column. A common practice to characterise chromatographic columns is to estimate the efficiency and asymmetry factor for the peaks of one or more solutes eluted at selected experimental conditions. This has the drawback that the extra-column contributions to the peak variance and skewness make the peak shape parameters depend on the retention time. We propose and discuss here the use of several approaches that allow the estimation of global parameters (non-dependent on the retention time) to describe the column performance. The global parameters arise from different linear relationships that can be established between the peak variance, standard deviation, or half-widths with the retention time. Some of them describe exclusively the column contribution to the peak broadening, whereas others consider the extra-column effects also. The estimation of peak skewness was also possible for the approaches based on the half-widths. The proposed approaches were applied to the characterisation of different columns (Spherisorb, Zorbax SB, Zorbax Eclipse, Kromasil, Chromolith, X-Terra and Inertsil), using the chromatographic data obtained for several diuretics and basic drugs (beta-blockers). Copyright (c) 2010 Elsevier B.V. All rights reserved.

A green method using a micellar system for determination of andrographolide and dehydroandrographolide in human plasma.

PubMed

Zhao, Qi; Ding, Jie; Jin, Haiyan; Ding, Lan; Ren, Nanqi

2013-04-01

A method based on cloud point extraction (CPE) coupled with high-performance liquid chromatography separation and ultraviolet (UV) detection was developed to determine andrographolide and dehydroandrographolide in human plasma. The nonionic surfactant Triton X-114 was chosen as the extraction medium. Variable parameters affecting the CPE efficiency were evaluated and optimized, such as concentrations of Triton X-114 and NaCl, pH, equilibration temperature and equilibration time. A Zorbax SB C18 column (250 × 4.6 mm i.d., 5 µm) was used for separation of the two analytes at 30°C. The UV detection was performed at 254 nm. Under the optimum conditions, the limits of detection of andrographolide and dehydroandrographolide are 0.032 and 0.019 µg/mL, respectively. The intra-day and inter-day precisions expressed as relative standard deviation ranged from 3.2 to 7.3% and from 2.9 and 8.6%. The recoveries of andrographolide and dehydroandrographolide were in the range of 76.8-98.6% at three fortified concentrations of 0.1, 0.5 and 1.0 µg/mL. This method was efficient, environmentally friendly, rapid and inexpensive for the extraction and determination of andrographolide and dehydroandrographolide in human plasma.

[Simultaneous determination of four compounds in Sanjing Shuanghuanglian Oral Liquid by high performance liquid chromatography-diode array detection-electrochemical detection].

PubMed

Liu, Lin; Suo, Zhirong; Zheng, Jianbin

2006-05-01

Chlorogenic acid, caffeic acid, baicalin and luteolin in Sanjing Shuanghuanglian Oral Liquid were simultaneously detected and identified using a high performance liquid chromatography coupled with diode array detection and electrochemical detection (HPLC-DAD-ECD). The separation was performed on a Zorbax SB-C18 column (150 mm x 4.6 mm i. d., 5.0 microm). The mobile phase consisted of (A) methanol and (B) methanol-water-acetic acid (50: 50: 1, v/v/v) using a linear gradient elution of 2%A-3%A at 0-3 min, 3%A-25%A at 3-15 min, 25%A-80%A at 15-20 min. The flow rate was 0.8 mL/min. The DAD detection was used at 275 nm. The ECD detection was done at 0.7 V. The column thermostat set at 30 degrees C. The limits of detection of the 4 compounds were 1 mg/L for chlorogenic acid, 0.2 mg/L for caffeic acid, 9 mg/L for baicalin, 7 mg/L for luteolin. The average recoveries were between 96.6%-99.6% with relative standard deviations (RSDs) of 2.5%-4.1%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four compounds in Shuanghuanglian Oral Liquid.

Chemical bonding in TiSb(2) and VSb(2): a quantum chemical and experimental study.

PubMed

Armbrüster, Marc; Schnelle, Walter; Schwarz, Ulrich; Grin, Yuri

2007-08-06

The chemical bonding in the isostructural intermetallic compounds TiSb2 and VSb2, crystallizing in the CuAl2 type, was investigated by means of quantum chemical calculations, particularly the electron localization function (ELF), as well as by Raman spectroscopy, Hall effect and conductivity measurements on oriented single crystals, and high-pressure X-ray powder diffraction. The homogeneity ranges of the compounds were determined by powder X-ray diffraction, WDXS, and DSC measurements. TiSb2 exhibits no significant homogeneity range, while VSb2 shows a small homogeneity range of approximately 0.3 at. %. According to the ELF calculations, the Sb atoms form dumbbells via a two-center two-electron bond, while the T atoms (T = Ti, V) build up chains along the crystallographic c-axis. Both building units are connected by covalent T-Sb-T three-center bonds, thus forming a three-dimensional network. The strength of the bonds involving Sb was determined by fitting a force constant model to the vibrational mode frequencies observed by polarized Raman measurements on oriented single crystals. The resulting bond order of the Sb2 dumbbells is 1, while the strength of the three-center bonds resembles a bond order of 1.5. The weak pressure dependence of the c/a ratio confirms the slightly different bonding picture in TiSb2 compared to that in CuAl2. Electrical transport measurements show the presence of free charge carriers, as well as a metal-like temperature dependence of the electrical resistivity.

Centrosymmetry vs noncentrosymmetry in La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} based on the interesting size effects of lanthanides: Syntheses, crystal structures, and optical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Hua-Jun, E-mail: cszzl772002@yeah.net; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002

Two new quaternary sulfides La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} have been prepared from stoichiometric elements at 1223 K in an evacuated silica tube. Interestingly, La{sub 2}Ga{sub 0.33}SbS{sub 5} crystallizes in the centrosymmetric structure, while Ce{sub 4}GaSbS{sub 9} crystallizes in the noncentrosymmetric structure, which show obvious size effects of lanthanides on the crystal structures of these two compounds. Ce{sub 4}GaSbS{sub 9} belongs to RE{sub 4}GaSbS{sub 9} (RE=Pr, Nd, Sm, Gd–Ho) structure type with a=13.8834(9) Å, b=14.3004(11) Å, c=14.4102(13) Å, V=2861.0(4) Å{sup 3}. The structure features infinite chains of [Ga{sub 2}Sb{sub 2}S{sub 11}{sup 10–}]{sub ∞} propagating along a directionmore » separated by Ce{sup 3+} cations and S{sup 2−} anions. La{sub 2}Ga{sub 0.33}SbS{sub 5} adopts the family of La{sub 4}FeSb{sub 2}S{sub 10}-related structure with a=7.5193(6) Å, c=13.4126(17) Å, V=758.35(13) Å{sup 3}. Its structure is built up from the alternate stacking of La/Sb/S and La/Ga/S 2D building blocks. The La/Sb/S slabs consist of teeter-totter chains of Sb1S{sub 4} seesaws, which are connected via sharing the apexes of μ{sub 4}-S1. Moreover, La1 is positionally disordered with Sb1 and stabilized in a bicapped trigonal prismatic coordination sphere. Between these La/Sb/S slabs, La2S{sub 8} square antiprisms are connected via edge-sharing into 2D building blocks, creating tetrahedral sites partially occupied by the Ga1 atoms. UV/Vis diffuse reflectance spectroscopy study shows that the optical gap of La{sub 2}Ga{sub 0.33}SbS{sub 5} is about 1.76 eV. - Graphical abstract: Two new quaternary sulfides La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} have been prepared by solid-state reactions. Ce{sub 4}GaSbS{sub 9} crystallizes in RE{sub 4}GaSbS{sub 9} (RE=Pr, Nd, Sm, Gd–Ho) structure type, while La{sub 2}Ga{sub 0.33}SbS{sub 5} belongs to the family of La{sub 4}FeSb{sub 2}S{sub 10}-related structure and

Experimental Partitioning of As and SB Among Metal, Troilite, Schreibersite, Barringerite, and Metallic Liquid

NASA Astrophysics Data System (ADS)

Jones, J. H.; Casanova, I.

1993-07-01

We have performed a series of experiments to evaluate the behaviors of As and Sb in metallic systems. Because of the reputed chalcophile nature of these elements, we wrongly anticipated that they would follow S and that, compared to the Fe-X systems [1], (solid metal/liquid metal) partition coefficients would be considerably lower in S-bearing systems. Experimental and Analytical: Experiments were performed in sealed silica tubes as in [2]. Starting materials were high-purity metals, natural pyrite, and natural stibnite. Charges were doped either with As or Sb. Experiments were held at either 950 degrees C for six days or 1250 degrees C for three days. Typical experimental assemblages consisted either of taenite and coexisting Fe-Ni-S-X liquid (1250 degrees and 950 degrees C) or an assemblage of troilite, schreibersite, and Fe-Ni-S-P-X liquid (950 degrees C). The schreibersite-bearing, As-doped charge also contained barringerite (Fe,Ni)2P. Charges were mounted in epoxy, polished, and analyzed using a Cameca SX-50 electron microprobe and standard techniques. Results: Phases appeared homogeneous. Our results, along with partition coefficients inferred for the S-free system, are given in Table 1. Table 1 appears here in the hard copy. Discussion: Our results indicate that As behaves as a siderophile element at low temperatures, very analogous to Au. While the siderophility of Sb increases with decreasing temperature, it remains incompatible in solid metal. In this regard Sb is unique. Both As and Sb are very incompatible in troilite. Arsenic is weakly incompatible in schreibersite and strongly compatible in barringerite. Nickel shows no preference for either phosphide. Nickel partition coefficients for metal and schreibersite are similar to those measured previously [3]. On a lnD vs. ln(1-2 alpha X(S)) diagram [4], the data for Sb and As subparallel each other, indicating similar dependencies on S, despite their very different partition coefficients. Arsenic behaves

Structural and optical studies of nitrogen incorporation into GaSb-based GaInSb quantum wells

NASA Astrophysics Data System (ADS)

Nair, Hari P.; Crook, Adam M.; Yu, Kin M.; Bank, Seth R.

2012-01-01

We investigate the incorporation of nitrogen into (Ga,In)Sb grown on GaSb and report room temperature photoluminescence from GaInSb(N) quantum wells. X-ray diffraction and channeling nuclear reaction analysis, together with Rutherford backscattering, were employed to identify the optimal molecular beam epitaxial growth conditions that minimized the incorporation of non-substitutional nitrogen into GaNSb. Consistent with this hypothesis, GaInSb(N) quantum wells grown under the conditions that minimized non-substitutional nitrogen exhibited room temperature photoluminescence, indicative of significantly improved radiative efficiency. Further development of this material system could enable type-I laser diodes emitting throughout the (3-5 μm) wavelength range.

The hunt for LaFeSbO: Synthesis of La{sub 2}SbO{sub 2} and a case of mistaken identity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, Sean, E-mail: muirs@onid.orst.edu; Vielma, Jason, E-mail: vielmaj@onid.orst.edu; Schneider, Guenter, E-mail: guenter.schneider@oregonstate.edu

The phase La{sub 2}SbO{sub 2} has been identified and characterized in the course of our efforts to realize LaFeSbO, a composition of great interest to the superconductor community. The compound La{sub 2}SbO{sub 2} is a tetragonal layered oxypnictide containing La{sub 2}O{sub 2} layers similar to LaMPnO compositions (where M=transition metal, Pn=pnictide) separated by pnictide anion layers. In order to better understand why LaFeSbO has remained elusive, density functional theory calculations have been used to determine the ground state heats of formation for LaFeSbO, La{sub 2}SbO{sub 2}, and other competing phases within the La-Fe-Sb-O system, as well as the phonon spectrummore » for LaFeSbO. These efforts suggest that LaFeSbO is a potentially metastable composition. - Graphical abstract: The layered oxypnictide compounds La{sub 2}SbO{sub 2} and La{sub 1.9}Sr{sub 0.1}SbO{sub 2} have been synthesized and investigated. Both crystallize in a ThCr{sub 2}Si{sub 2} type configuration and are semiconducting. Stability of the unreported compound LaFeSbO has been investigated using density functional theory. A case of mistaken identity in the literature regarding the composition LaNiBiO is addressed. Highlights: Black-Right-Pointing-Pointer The composition La{sub 2}SbO{sub 2} has been identified. Black-Right-Pointing-Pointer La{sub 2}SbO{sub 2} belongs to an unusual group of materials containing Pn{sup 2-} anions. Black-Right-Pointing-Pointer La{sub 2}SbO{sub 2} and La{sub 1.9}Sr{sub 0.1}SbO{sub 2} are both found to be semiconducting. Black-Right-Pointing-Pointer DFT has been used to calculate heats of formation within the La-Fe-Sb-O system. Black-Right-Pointing-Pointer The phonon spectrum for LaFeSbO reveals no unstable lattice mode.« less

Technologies for thermal management of mid-IR Sb-based surface emitting lasers

NASA Astrophysics Data System (ADS)

Perez, J.-P.; Laurain, A.; Cerutti, L.; Sagnes, I.; Garnache, A.

2010-04-01

In this paper, for the first time to our knowledge, we report and demonstrate the technological steps dedicated to thermal management of antimonide-based surface emitting laser devices grown by molecular beam epitaxy. Key points of the technological process are firstly the bonding of the structure on the SiC host substrate and secondly the GaSb substrate removal to leave the Sb-based membrane. The structure design (etch stop layer, metallic mirror, etc), bonding process (metallic bonding via solid-liquid interdiffusion) and GaSb substrate removal process (selective wet-chemical etchants, etc) are presented. Optical characterizations together with external-cavity VCSEL laser emission at 2.3 µm at room temperature in continuous wave are presented.

Internally consistent database for sulfides and sulfosalts in the system Ag 2S-Cu 2S-ZnS-Sb 2S 3-As 2S 3

NASA Astrophysics Data System (ADS)

Sack, Richard O.

2000-11-01

An updated thermodynamic database for Ag 2S-Cu 2S-ZnS-Sb 2S 3-As 2S 3 sulfides and sulfosalts applicable to temperatures above 119°C is developed to calculate phase relations for polybasite-pearceite- and fahlore-bearing assemblages. It is based on pre-existing and new constraints on activity-composition, Ag-Cu and As-Sb partitioning, and other relations, and on experiments (200-300°C, evacuated silica tubes) conducted to define the stability of the polybasite-pearceite [(Ag 1- x,Cu x) 16(Sb 1- y,As y) 2S 11] + ZnS sphalerite assemblage with respect to assemblages containing (Ag,Cu) 2S sulfides coexisting with (Cu, Ag) 10Zn 2(Sb,As) 4S 13 fahlore sulfosalts. It was found that the thermodynamics of mixing of bcc- and hcp-(Ag,Cu) 2S solutions, which are fast-ion conductors, may be described by using site multiplicities of metals α Ag,Cu > 2 and temperature-dependent regular solution parameters. We obtained estimates for the Gibbs energies of formation for Ag 16Sb 2S 11 and Cu 16Sb 2S 11 polybasite endmembers from the simple sulfides (Ag 2S, Cu 2S, and Sb 2S 3) of -30.79 and -4.07 kJ/gfw at 200°C, and -32.04 and -0.59 kJ/gfw at 400°C, respectively, that are about one half kJ/gfw more positive and about 6 kJ/gfw more negative than those estimated by Harlov and Sack (1995b). The corresponding estimates for formation energies of Ag 10Zn 2Sb 4S 13 and Cu 10Zn 2Sb 4S 13 fahlores (-20.29 and -105.29 kJ/gfw at 200°C and -23.72 and -105.76 kJ/gfw at 400°C) are comparable to, and roughly 110 kJ/gfw more positive than, the corresponding estimates of Ebel and Sack (1994). We also determined that the Gibbs energies of the As-Sb exchange reactions: 1/4Ag 10Zn2Sb4S13+1/2Ag 16As2S11=1/2Ag 16Sb2S11+1/4Ag 10Zn2As4S13Sb-fahlorepearceitepolybasiteAs-fahlore and Ag3SbS3+1/2Ag 16As2S11=1/2Ag 16Sb2S11+Ag3AsS3pyrargyritepearceitepolybasiteproustite are, respectively, 8.75 and 0.40 kJ/gfw in the range 150-350°C, and these predictions are consistent with As-Sb partitioning relations

Investigation of spin-dependent transports and microstructure in NiMnSb-based magnetoresistive devices

NASA Astrophysics Data System (ADS)

Qu, Guanxiong; Cheng, P.-H.; Du, Ye; Sakuraba, Yuya; Kasai, Shinya; Hono, Kazuhiro

2017-11-01

We have fabricated fully epitaxial current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices using C1b-half Heusler compound NiMnSb, the first candidate of the half-metallic material, as the electrode with a Ag spacer. The device shows magnetoresistance ratios of 25% at 4.2 K and 9.6% at 290 K, which are one of the highest values for the CPP-GMR with half-Heusler compounds. However, these values are much lower compared to those reported for CPP-GMR devices with L21-full Heusler compounds. Careful analysis of the microstructure using scanning transmission electron microscopy and energy dispersive spectroscopy through the upper NiMnSb/Ag interface indicates the heterogeneous formation of Ag-rich solid solution or the island growth of Ag on top of NiMnSb, which clarified a difficulty in evaluating an intrinsic spin-polarization in NiMnSb from CPP-GMR devices. Thus, to evaluate a spin-polarization of a NiMnSb thin film, we fabricated non-local spin valve (NLSV) devices using NiMnSb with Cu channel wires, which is free from the diffusion of Cu to NiMnSb because of no annealing proccess after deposition of Cu. Finally, intrinsic spin polarization of the NiMnSb single layer was extrapolated to be around 50% from NLSV, suggesting a difficulty in obtaining half-metallic nature in the NiMnSb epitaxial thin film.

Electronic structure modeling of InAs/GaSb superlattices with hybrid density functional theory

NASA Astrophysics Data System (ADS)

Garwood, T.; Modine, N. A.; Krishna, S.

2017-03-01

The application of first-principles calculations holds promise for greatly improving our understanding of semiconductor superlattices. Developing a procedure to accurately predict band gaps using hybrid density functional theory lays the groundwork for future studies investigating more nuanced properties of these structures. Our approach allows a priori prediction of the properties of SLS structures using only the band gaps of the constituent materials. Furthermore, it should enable direct investigation of the effects of interface structure, e.g., intermixing or ordering at the interface, on SLS properties. In this paper, we present band gap data for various InAs/GaSb type-II superlattice structures calculated using the generalized Kohn-Sham formulation of density functional theory. A PBE0-type hybrid functional was used, and the portion of the exact exchange was tuned to fit the band gaps of the binary compounds InAs and GaSb with the best agreement to bulk experimental values obtained with 18% of the exact exchange. The heterostructures considered in this study are 6 monolayer (ML) InAs/6 ML GaSb, 8 ML InAs/8 ML GaSb and 10 ML InAs/10 ML GaSb with deviations from the experimental band gaps ranging from 3% to 11%.

Electronic structure modeling of InAs/GaSb superlattices with hybrid density functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garwood, Tristan; Modine, Normand A.; Krishna, S.

2016-12-18

The application of first-principles calculations holds promise for greatly improving our understanding of semiconductor superlattices. By developing a procedure to accurately predict band gaps using hybrid density functional theory, it lays the groundwork for future studies investigating more nuanced properties of these structures. Our approach allows a priori prediction of the properties of SLS structures using only the band gaps of the constituent materials. Furthermore, it should enable direct investigation of the effects of interface structure, e.g., intermixing or ordering at the interface, on SLS properties. In this paper, we present band gap data for various InAs/GaSb type-II superlattice structuresmore » calculated using the generalized Kohn-Sham formulation of density functional theory. A PBE0-type hybrid functional was used, and the portion of the exact exchange was tuned to fit the band gaps of the binary compounds InAs and GaSb with the best agreement to bulk experimental values obtained with 18% of the exact exchange. The heterostructures considered in this study are 6 monolayer (ML) InAs/6 ML GaSb, 8 ML InAs/8 ML GaSb and 10 ML InAs/10 ML GaSb with deviations from the experimental band gaps ranging from 3% to 11%.« less

Antiferromagnetism in EuCu 2As 2 and EuCu 1.82Sb 2 single crystals

DOE PAGES

Anand, V. K.; Johnston, D. C.

2015-05-07

Single crystals of EuCu 2As 2 and EuCu 2Sb 2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat C p(T), and electrical resistivity ρ(T) measurements. EuCu 2As 2 crystallizes in the body-centered tetragonal ThCr 2Si 2-type structure (space group I4/mmm), whereas EuCu 2Sb 2 crystallizes in the related primitive tetragonal CaBe 2Ge 2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for themore » EuCu 2Sb 2 crystals showed the presence of vacancies on the Cu sites, yielding the actual composition EuCu 1.82Sb 2. The ρ(T) and C p(T) data reveal metallic character for both EuCu 2As 2 and EuCu 1.82Sb 2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),C p(T), and ρ(T) data for both EuCu 2As 2 (T N = 17.5 K) and EuCu 1.82Sb 2 (T N = 5.1 K). In EuCu 1.82Sb 2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu +2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu 2As 2, also containing Eu +2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar.« less

Study on anisotropy of n-type Mg3Sb2-based thermoelectric materials

NASA Astrophysics Data System (ADS)

Song, Shaowei; Mao, Jun; Shuai, Jing; Zhu, Hangtian; Ren, Zhensong; Saparamadu, Udara; Tang, Zhongjia; Wang, Bo; Ren, Zhifeng

2018-02-01

The recent discovery of a high thermoelectric figure of merit (ZT) in an n-type Mg3Sb2-based Zintl phase triggered an intense research effort to pursue even higher ZT. Based on our previous report on Mg3.1Nb0.1Sb1.5Bi0.49Te0.01, we report here that partial texturing in the (001) plane is achieved by double hot pressing, which is further confirmed by the rocking curves of the (002) plane. The textured samples of Mg3.1Nb0.1Sb1.5Bi0.49Te0.01 show a much better average performance in the (00l) plane. Hall mobility is significantly improved to ˜105 cm2 V-1 s-1 at room temperature in the (00l) plane due to texturing, resulting in higher electrical conductivity, a higher power factor of ˜18 μW cm-1 K-2 at room temperature, and also higher average ZT. This work shows that texturing is good for higher thermoelectric performance, suggesting that single crystals of n-type Mg3Sb2-based Zintl compounds are worth pursuing.

Simultaneous ultra-long data retention and low power based on Ge10Sb90/SiO2 multilayer thin films

NASA Astrophysics Data System (ADS)

You, Haipeng; Hu, Yifeng; Zhu, Xiaoqin; Zou, Hua; Song, Sannian; Song, Zhitang

2018-02-01

In this article, Ge10Sb90/SiO2 multilayer thin films were prepared to improve thermal stability and data retention for phase change memory. Compared with Ge10Sb90 monolayer thin film, Ge10Sb90 (1 nm)/SiO2 (9 nm) multilayer thin film had higher crystallization temperature and resistance contrast between amorphous and crystalline states. Annealed Ge10Sb90 (1 nm)/SiO2 (9 nm) had uniform grain with the size of 15.71 nm. After annealing, the root-mean-square surface roughness for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film increased slightly from 0.45 to 0.53 nm. The amorphization time for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film (2.29 ns) is shorter than Ge2Sb2Te5 (3.56 ns). The threshold voltage of a cell based on Ge10Sb90 (1 nm)/SiO2 (9 nm) (3.57 V) was smaller than GST (4.18 V). The results indicated that Ge10Sb90/SiO2 was a promising phase change thin film with high thermal ability and low power consumption for phase change memory application.

A randomized phase l pharmacokinetic study comparing SB4 and etanercept reference product (Enbrel®) in healthy subjects

PubMed Central

Shin, Donghoon; Kim, Youngdoe; Kang, Jungwon; Gauliard, Anke; Fuhr, Rainard

2016-01-01

Aims SB4 has been developed as a biosimilar of etanercept. The primary objective of the present study was to demonstrate the pharmacokinetic (PK) equivalence between SB4 and European Union ‐sourced etanercept (EU‐ETN), SB4 and United States‐sourced etanercept (US‐ETN), and EU‐ETN and US‐ETN. The safety and immunogenicity were also compared between the treatments. Methods This was a single‐blind, three‐part, crossover study in 138 healthy male subjects. In each part, 46 subjects were randomized at a 1:1 ratio to receive a single 50 mg subcutaneous dose of the treatments (part A: SB4 or EU‐ETN; part B: SB4 or US‐ETN; and part C: EU‐ETN or US‐ETN) in period 1, followed by the crossover treatment in period 2 according to their assigned sequences. PK equivalence between the treatments was determined using the standard equivalence margin of 80–125%. Results The geometric least squares means ratios of AUCinf, AUClast and Cmax were 99.04%, 98.62% and 103.71% (part A: SB4 vs. EU‐ETN); 101.09%, 100.96% and 104.36% (part B: SB4 vs. US‐ETN); and 100.51%, 101.27% and 103.29% (part C: EU‐ETN vs. US‐ETN), respectively, and the corresponding 90% confidence intervals were completely contained within the limits of 80–125 %. The incidence of treatment‐emergent adverse events was comparable, and the incidence of the antidrug antibodies was lower in SB4 compared with the reference products. Conclusions The present study demonstrated PK equivalence between SB4 and EU‐ETN, SB4 and US‐ETN, and EU‐ETN and US‐ETN in healthy male subjects. SB4 was well tolerated, with a lower immunogenicity profile and similar safety profile compared with those of the reference products. PMID:26972584

The gas-phase on-line formation of antimony oxide trihalides, SbOX 3 where X=F and Cl and their identifications by infrared spectroscopy

NASA Astrophysics Data System (ADS)

Allaf, Abdul W.; Ajji, Z.

2000-09-01

Antimony oxide trihalides, SbOX 3 molecules, where X=F or Cl have been produced, by means of an on-line process, using antimony trichloride, SbOCl 3 as starting material passed over heated silver oxide at 230°C. The antimony oxide trichloride SbOCl 3 formed is then reacted with sodium fluoride, NaF at 550°C to produce antimony oxide trifluoride, SbOF 3. The products have been characterized by the IR spectra of their vapors. Low resolution gas-phase Fourier transform infrared spectra show strong bands centered at 1272 and 1217 cm -1, assigned to ν 1(a 1), the OSb stretching fundamental of SbOF 3 and SbOCl 3, respectively. Both observed bands show typical PQR-type structure with a strong Q-head.

Structural and luminescent Properties of Bulk InAsSb

DTIC Science & Technology

2011-12-21

have used compositionally graded metamorphic buffer layers to accommodate the misfit strain between InAsxSb1-x alloys and GaSb and InSb substrates in...wavelength range. The authors have used compositionally graded metamorphic buffer layers to accommodate the misfit strain between InAsxSb1x alloys...long wave IR range. We used compositionally graded GaInSb, AlGaInSb, and InAsxSb1x metamorphic buffer layers to accommodate the misfit strain between

Sb-induced strain fluctuations in a strained layer superlattice of InAs/InAsSb

NASA Astrophysics Data System (ADS)

Kim, Honggyu; Meng, Yifei; Klem, John F.; Hawkins, Samuel D.; Kim, Jin K.; Zuo, Jian-Min

2018-04-01

We show that Sb substitution for As in a MBE grown InAs/InAsSb strained layer superlattice (SLS) is accompanied by significant strain fluctuations. The SLS was observed using scanning transmission electron microscopy along the [100] zone axis where the cation and anion atomic columns are separately resolved. Strain analysis based on atomic column positions reveals asymmetrical transitions in the strain profile across the SLS interfaces. The averaged strain profile is quantitatively fitted to the segregation model, which yields a distribution of Sb in agreement with the scanning tunneling microscopy result. The subtraction of the calculated strain reveals an increase in strain fluctuations with the Sb concentration, as well as isolated regions with large strain deviations extending spatially over ˜1 nm, which suggest the presence of point defects.

High current density Esaki tunnel diodes based on GaSb-InAsSb heterostructure nanowires.

PubMed

Ganjipour, Bahram; Dey, Anil W; Borg, B Mattias; Ek, Martin; Pistol, Mats-Erik; Dick, Kimberly A; Wernersson, Lars-Erik; Thelander, Claes

2011-10-12

We present electrical characterization of broken gap GaSb-InAsSb nanowire heterojunctions. Esaki diode characteristics with maximum reverse current of 1750 kA/cm(2) at 0.50 V, maximum peak current of 67 kA/cm(2) at 0.11 V, and peak-to-valley ratio (PVR) of 2.1 are obtained at room temperature. The reverse current density is comparable to that of state-of-the-art tunnel diodes based on heavily doped p-n junctions. However, the GaSb-InAsSb diodes investigated in this work do not rely on heavy doping, which permits studies of transport mechanisms in simple transistor structures processed with high-κ gate dielectrics and top-gates. Such processing results in devices with improved PVR (3.5) and stability of the electrical properties.

Simultaneous determination of febuxostat and its three active metabolites in human plasma by liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study in Chinese healthy volunteers.

PubMed

Wu, Yingli; Mao, Zhengsheng; Liu, Youping; Wang, Xin; Di, Xin

2015-10-10

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of febuxostat and its three active metabolites in human plasma was developed using a ZORBAX SB-C18 column (50 mm × 4.6 mm, 5 μm) and an optimized gradient mobile phase consisting of acetonitrile, water and formic acid. Plasma samples were spiked with the internal standard losartan and then pre-treated using one-step protein precipitation with methanol. Mass spectrometric detection was performed by selective reaction monitoring mode via electrospray ionization source operating in positive ionization mode. The method exhibited good linearity over the concentration range of 10-20,000 ng/mL for febuxostat, 1.0-270 ng/mL for 67M-1 and 67M-2, and 0.8-250 ng/mL for 67 M-4, respectively. The intra- and inter-day precisions were less than 14.7% and the accuracy ranged from -4.3% to 5.1%. The method was successfully applied to a clinical pharmacokinetic study of febuxostat in humans after oral administration of a single dose of febuxostat at 40, 80 and 120 mg. Copyright © 2015 Elsevier B.V. All rights reserved.

Description of Adsorption in Liquid Chromatography under Nonideal Conditions.

PubMed

Ortner, Franziska; Ruppli, Chantal; Mazzotti, Marco

2018-05-15

A thermodynamically consistent description of binary adsorption in reversed-phase chromatography is presented, accounting for thermodynamic nonidealities in the liquid and adsorbed phases. The investigated system involves the adsorbent Zorbax 300SB-C18, as well as phenetole and 4- tert-butylphenol as solutes and methanol and water as inert components forming the eluent. The description is based on adsorption isotherms, which are a function of the liquid-phase activities, to account for nonidealities in the liquid phase. Liquid-phase activities are calculated with a UNIQUAC model established in this work, based on experimental phase equilibrium data. The binary interaction in the adsorbed phase is described by the adsorbed solution theory, assuming an ideal (ideal adsorbed solution theory) or real (real adsorbed solution theory) adsorbed phase. Implementation of the established adsorption model in a chromatographic code achieves a quantitative description of experimental elution profiles, with feed compositions exploiting the entire miscible region, and involving a broad range of different eluent compositions (methanol/water). The quantitative agreement of the model and experimental data serves as a confirmation of the underlying physical (thermodynamic) concepts and of their applicability to a broad range of operating conditions.

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

PubMed

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

2006-05-03

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

Development of LC-MS determination method and back-propagation ANN pharmacokinetic model of corynoxeine in rat.

PubMed

Ma, Jianshe; Cai, Jinzhang; Lin, Guanyang; Chen, Huilin; Wang, Xianqin; Wang, Xianchuan; Hu, Lufeng

2014-05-15

Corynoxeine(CX), isolated from the extract of Uncaria rhynchophylla, is a useful and prospective compound in the prevention and treatment for vascular diseases. A simple and selective liquid chromatography mass spectrometry (LC-MS) method was developed to determine the concentration of CX in rat plasma. The chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm × 150 mm, 5 μm) column with acetonitrile-0.1% formic acid in water as mobile phase. Selective ion monitoring (SIM) mode was used for quantification using target ions m/z 383 for CX and m/z 237 for the carbamazepine (IS). After the LC-MS method was validated, it was applied to a back-propagation artificial neural network (BP-ANN) pharmacokinetic model study of CX in rats. The results showed that after intravenous administration of CX, it was mainly distributed in blood and eliminated quickly, t1/2 was less than 1h. The predicted concentrations generated by BP-ANN model had a high correlation coefficient (R>0.99) with experimental values. The developed BP-ANN pharmacokinetic model can be used to predict the concentration of CX in rats. Copyright © 2014 Elsevier B.V. All rights reserved.

Facile synthesis of hybrid nanorods with the Sb2Se3/AgSbSe2 heterojunction structure for high performance photodetectors.

PubMed

Chen, Shuo; Qiao, Xvsheng; Wang, Fengxia; Luo, Qun; Zhang, Xianghua; Wan, Xia; Xu, Yang; Fan, Xianping

2016-01-28

An effective colloidal process involving the hot-injection method is developed to synthesize uniform single-crystalline Sb2Se3 nanorods in high yields. The photoconductive characteristics of the as-synthesized Sb2Se3 nanorods are investigated by developing a film-based photodetector and this device displays a remarkable response to visible light with an "ON/OFF" ratio as high as 50 (with an incident light density of 12.05 mW cm(-2)), short response/recovery times and long-term durability. To overcome the challenge of the intrinsic low electrical conductivity of Sb2Se3, hybrid nanorods with the Sb2Se3/AgSbSe2 heterojunction structure having a type-II band alignment are firstly prepared. The electric current of the photodetector based on the Sb2Se3/AgSbSe2 hybrid nanorod film has been significantly increased both in the dark and under light illumination. The responsivity of the photodetector based on the Sb2Se3/AgSbSe2 hybrid nanorod film is about 4.2 times as much as that of the photodetector based on the Sb2Se3 nanorod film. This improvement can be considered as an important step to promote Sb2Se3 based semiconductors for applications in high performance photodetectors.

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2012 CFR

2012-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2013 CFR

2013-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2014 CFR

2014-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

Enhanced Sb 2Se 3 solar cell performance through theory-guided defect control: Enhanced Sb 2Se 3 solar cell performance

DOE PAGES

Liu, Xinsheng; Xiao, Xun; Yang, Ye; ...

2017-05-30

Defects present in the absorber layer largely dictate photovoltaic device performance. Recently, a binary photovoltaic material, Sb 2Se 3, has drawn much attention due to its low-cost and nontoxic constituents and rapid performance promotion. So far, however, the intrinsic defects of Sb 2Se 3 remain elusive. Here in this work, through a combined theoretical and experimental investigation, we revealed that shallow acceptors, SeSb antisites, are the dominant defects in Sb 2Se 3 produced in an Se-rich environment, where deep donors, SbSe and VSe, dominate in Sb 2Se 3 produced in an Se-poor environment. We further constructed a superstrate CdS/Sb 2Semore » 3 thin-film solar cell achieving 5.76% efficiency through in situ Se compensation during Sb 2Se 3 evaporation and through careful optimization of absorber layer thickness. In conclusion, the understanding of intrinsic defects in Sb 2Se 3 film and the demonstrated success of in situ Se compensation strategy pave the way for further efficiency improvement of this very promising photovoltaic technology.« less

18 CFR 3c.2 - Nonpublic information.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Nonpublic information. 3c.2 Section 3c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION...)) of the Federal Power Act, and section 8(b) (15 U.S.C. 717g) of the Natural Gas Act prohibit any...

On the electronic properties of GaSb irradiated with reactor neutrons and its charge neutrality level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boiko, V. M.; Brudnii, V. N., E-mail: brudnyi@mail.tsu.ru; Ermakov, V. S.

2015-06-15

The electronic properties and the limiting position of the Fermi level in p-GaSb crystals irradiated with full-spectrum reactor neutrons at up to a fluence of 8.6 × 10{sup 18} cm{sup −2} are studied. It is shown that the irradiation of GaSb with reactor neutrons results in an increase in the concentration of free holes to p{sub lim} = (5−6) × 10{sup 18} cm{sup −3} and in pinning of the Fermi level at the limiting position F{sub lim} close to E{sub V} + 0.02 eV at 300 K. The effect of the annealing of radiation defects in the temperature range 100–550°Cmore » is explored.« less

40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids are...

40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids are...

Fine genetic mapping of spot blotch resistance gene Sb3 in wheat (Triticum aestivum).

PubMed

Lu, Ping; Liang, Yong; Li, Delin; Wang, Zhengzhong; Li, Wenbin; Wang, Guoxin; Wang, Yong; Zhou, Shenghui; Wu, Qiuhong; Xie, Jingzhong; Zhang, Deyun; Chen, Yongxing; Li, Miaomiao; Zhang, Yan; Sun, Qixin; Han, Chenggui; Liu, Zhiyong

2016-03-01

Spot blotch disease resistance gene Sb3 was mapped to a 0.15 centimorgan (cM) genetic interval spanning a 602 kb physical genomic region on chromosome 3BS. Wheat spot blotch disease, caused by B. sorokiniana, is a devastating disease that can cause severe yield losses. Although inoculum levels can be reduced by planting disease-free seed, treatment of plants with fungicides and crop rotation, genetic resistance is likely to be a robust, economical and environmentally friendly tool in the control of spot blotch. The winter wheat line 621-7-1 confers immune resistance against B. sorokiniana. Genetic analysis indicates that the spot blotch resistance of 621-7-1 is controlled by a single dominant gene, provisionally designated Sb3. Bulked segregant analysis (BSA) and simple sequence repeat (SSR) mapping showed that Sb3 is located on chromosome arm 3BS linked with markers Xbarc133 and Xbarc147. Seven and twelve new polymorphic markers were developed from the Chinese Spring 3BS shotgun survey sequence contigs and 3BS reference sequences, respectively. Finally, Sb3 was mapped in a 0.15 cM genetic interval spanning a 602 kb physical genomic region of Chinese Spring chromosome 3BS. The genetic and physical maps of Sb3 provide a framework for map-based cloning and marker-assisted selection (MAS) of the spot blotch resistance.

[Replication of Streptomyces plasmids: the DNA nucleotide sequence of plasmid pSB 24.2].

PubMed

Bolotin, A P; Sorokin, A V; Aleksandrov, N N; Danilenko, V N; Kozlov, Iu I

1985-11-01

The nucleotide sequence of DNA in plasmid pSB 24.2, a natural deletion derivative of plasmid pSB 24.1 isolated from S. cyanogenus was studied. The plasmid amounted by its size to 3706 nucleotide pairs. The G-C composition was equal to 73 per cent. The analysis of the DNA structure in plasmid pSB 24.2 revealed the protein-encoding sequence of DNA, the continuity of which was significant for replication of the plasmid containing more than 1300 nucleotide pairs. The analysis also revealed two A-T-rich areas of DNA, the G-C composition of which was less than 55 per cent and a DNA area with a branched pin structure. The results may be of value in investigation of plasmid replication in actinomycetes and experimental cloning of DNA with this plasmid as a vector.

Surface passivation of (100) GaSb using self-assembled monolayers of long-chain octadecanethiol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papis-Polakowska, E., E-mail: papis@ite.waw.pl; Kaniewski, J.; Jurenczyk, J.

2016-05-15

The passivation of (100) GaSb surface was investigated by means of the long-chain octadecanethiol (ODT) self-assembled monolayer (SAM). The properties of ODT SAM on (100) GaSb were characterized by the atomic force microscopy using Kelvin probe force microscopy mode and X-ray photoelectron spectroscopy. The chemical treatment of 10 mM ODT-C{sub 2}H{sub 5}OH has been applied to the passivation of a type-II superlattice InAs/GaSb photodetector. The electrical measurements indicate that the current density was reduced by one order of magnitude as compared to an unpassivated photodetector.

Unconstrained Heterogeneous Colloidal Quantum Dots Embedded in GaAs/GaSb Nanovoids

DTIC Science & Technology

2014-04-17

ex-situ techniques when it comes to both CQD integration as well as regrowth, since the surface is free of contaminants and native oxides . 3.0...monitor the growth surface. The growth was started on a GaSb substrate through a thermal oxide desorption process at 540 C and then a GaSb smoothing...reduces the danger of contamination and/or oxidation of the produced CQDs, and also provides for the removal of any gas byproducts from the

Effects of Processing and Storage on Pediococcus pentosaceus SB83 in Vaginal Formulations: Lyophilized Powder and Tablets

PubMed Central

Borges, Sandra; Costa, Paulo; Silva, Joana; Teixeira, Paula

2013-01-01

Vaginal probiotics have an important role in preventing the colonization of the vagina by pathogens. This study aimed to investigate different formulations with Pediococcus pentosaceus SB83 (lyophilized powder and tablets with and without retarding polymer) in order to verify its stability and antilisterial activity after manufacture and during storage. The bacteriocinogenic activity of P. pentosaceus SB83 against Listeria monocytogenes was evaluated in simulated vaginal fluid. Suspension of Pediococcus pentosaceus SB83 reduced the pathogen only after 2 h and the lyophilized bacteria after 24 h of contact, and, in the tablets, P. pentosaceus SB83 lost the antimicrobial activity. The pH of simulated vaginal fluid decreased for all the tested conditions. As lyophilized powder demonstrated better results concerning antimicrobial activity, this formulation was selected to evaluate the antilisterial activity during the 12 months of storage. During storage at room temperature, lyophilized bacteria totally inhibited the pathogen only until one month of storage. At 4°C, P. pentosaceus SB83 showed antimicrobial activity during all the time of storage investigated. Therefore, the better formulation of P. pentosaceus SB83 is the lyophilized powder stored at 4°C, which may be administered intravaginally as a washing solution. PMID:23844367

Sb-induced strain fluctuations in a strained layer superlattice of InAs/InAsSb

DOE PAGES

Kim, Honggyu; Meng, Yifei; Klem, John F.; ...

2018-04-28

Here, we show that Sb substitution for As in a MBE grown InAs/InAsSb strained layer superlattice (SLS) is accompanied by significant strain fluctuations. The SLS was observed using scanning transmission electron microscopy along the [100] zone axis where the cation and anion atomic columns are separately resolved. Strain analysis based on atomic column positions reveals asymmetrical transitions in the strain profile across the SLS interfaces. The averaged strain profile is quantitatively fitted to the segregation model, which yields a distribution of Sb in agreement with our scanning tunneling microscopy result. The subtraction of the calculated strain reveals an increase inmore » strain fluctuations with the Sb concentration, as well as isolated regions with large strain deviations extending spatially over ~1 nm, which suggest the presence of point defects.« less

Sb-induced strain fluctuations in a strained layer superlattice of InAs/InAsSb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Honggyu; Meng, Yifei; Klem, John F.

Here, we show that Sb substitution for As in a MBE grown InAs/InAsSb strained layer superlattice (SLS) is accompanied by significant strain fluctuations. The SLS was observed using scanning transmission electron microscopy along the [100] zone axis where the cation and anion atomic columns are separately resolved. Strain analysis based on atomic column positions reveals asymmetrical transitions in the strain profile across the SLS interfaces. The averaged strain profile is quantitatively fitted to the segregation model, which yields a distribution of Sb in agreement with our scanning tunneling microscopy result. The subtraction of the calculated strain reveals an increase inmore » strain fluctuations with the Sb concentration, as well as isolated regions with large strain deviations extending spatially over ~1 nm, which suggest the presence of point defects.« less

Effect of an in situ Hydrogen Plasma Pre-treatment on the Reduction of GaSb Native oxides Prior to Atomic Layer Deposition

DTIC Science & Technology

2013-04-12

absence of Sb-oxides, a reduction in elemental Sb, and an increase in the Ga2O3 content at the interface. The use of an in situ hydrogen...elemental Sb, and an increase in the Ga2O3 content at the interface. The use of an in situ hydrogen plasma pre-treatment eliminates the need for wet...the +1 state (Ga2O) and the +3 state ( Ga2O3 ), with peak positions found at 530.5 eV (Sb2O4), 20.1 eV (Ga2O), and 20.7 eV ( Ga2O3 ) [11,18]. The AFM image

Transport properties of Sb-doped Si nanowires

NASA Astrophysics Data System (ADS)

Nukala, Prathyusha; Sapkota, Gopal; Gali, Pradeep; Philipose, U.

2012-08-01

We present a safe and cost-effective approach for synthesis of n-type Sb-doped Si nanowires. The nanowires were synthesized at ambient pressure using SiCl4 as Si source and pure Sb as the dopant source. Structural and compositional characterization using electron microscopy and X-ray spectroscopy show crystalline nanowires with lengths of 30-40 μm and diameters of 40-100 nm. A 3-4 nm thick amorphous oxide shell covers the surface of the nanowire, post-growth. The composition of this shell was confirmed by Raman spectroscopy. Growth of Si nanowires, followed by low temperature annealing in Sb vapor, was shown to be an effective technique for synthesizing Sb-doped Si nanowires. The doping concentration of Sb was found to be dependent on temperature, with Sb re-evaporating from the Si nanowire at higher doping temperatures. Field effect transistors (FETs) were fabricated to investigate the electrical transport properties of these nanowires. The as-grown Si nanowires were found to be p-type with a channel mobility of 40 cm2 V-1 s-1. After doping with Sb, these nanowires exhibited n-type behavior. The channel mobility and carrier concentration of the Sb-doped Si nanowires were estimated to be 288 cm2 V-1 s-1 and 5.3×1018 cm-3 respectively.

Extension of the carotenoid test to superficially porous C18 bonded phases, aromatic ligand types and new classical C18 bonded phases.

PubMed

Lesellier, E

2012-11-30

The recent introduction of new stationary phases for liquid chromatography based on superficially porous particles, called core-shell or fused-core, dramatically improved the separation performances through very high efficiency, due mainly to reduced eddy diffusion. However, few studies have evaluated the retention and selectivity of C18 phases based on such particles, despite some retention order change reported in literature between some of these phases. The carotenoid test has been developed a few years ago in the goal to compare the chromatographic properties of C18 bonded phases. Based on the analysis of carotenoid pigments by using Supercritical Fluid Chromatography (SFC), it allows, with a single analysis, to measure three main properties of reversed phase chromatography stationary phases: hydrophobicity, polar surface activity and shape selectivity. Previous studies showed the effect of the endcapping treatment, the bonding density, the pore size, and the type of bonding (monomeric vs. polymeric) on these studied properties, and described the classification map used for a direct column comparison. It was applied to ten ODS superficially porous stationary phases, showing varied chromatographic behaviors amongst these phases. As expected, due to the lower specific surface area, these superficially porous phases are less hydrophobic than the fully porous one. In regards of the polar surface activity (residual silanols) and to the shape selectivity, some of these superficially porous phases display close chromatographic properties (Poroshell 120, Halo C18, Ascentis Express, Accucore C18, Nucleoshell C18 on one side and Aeris Wide pore, Aeris peptide and Kinetex XDB on the other side), whereas others, Kinetex C18 and Halo peptide ES C18 display more specific ones. Besides, they can be compared to classical fully porous phases, in the goal to improve method transfer from fully to superficially porous particles. By the way, the paper also report the extension of

Oral administration of the 5-HT6 receptor antagonists SB-357134 and SB-399885 improves memory formation in an autoshaping learning task.

PubMed

Perez-García, Georgina; Meneses, Alfredo

2005-07-01

In this work we aimed to re-examine the 5-HT6 receptor role, by testing the selective antagonists SB-357134 (1-30 mg/kg p.o.) and SB-399885 (1-30 mg/kg p.o.) during memory consolidation of conditioned responses (CR%), in an autoshaping Pavlovian/instrumental learning task. Bioavailability, half-life and minimum effective dose to induce inappetence for SB-357134 were 65%, 3.4 h, and 30 mg/kg p.o., and for SB-399885 were 52%, 2.2 h, and 50 mg/kg p.o., respectively. Oral acute and chronic administration of either SB-357134 or SB-399885 improved memory consolidation compared to control groups. Acute administration of SB-357134, at 1, 3, 10 and 30 mg/kg, produced a CR% inverted-U curve, eliciting the latter dose a 7-fold increase relative to saline group. Acute injection of SB-399885 produced significant CR% increments, being 1 mg/kg the most effective dose. Repeated administration (7 days) of either SB-357134 (10 mg/kg) or SB-399885 (1 mg/kg) elicited the most significant CR% increments. Moreover, modeling the potential therapeutic benefits of 5-HT6 receptor blockade, acute or repeated administration of SB-399885, at 10 mg/kg reversed memory deficits produced by scopolamine or dizocilpine, and SB-357134 (3 and 10 mg/kg) prevented amnesia and even improved performance. These data support the notion that endogenously 5-HT acting, via 5-HT6 receptor, improves memory consolidation.

Superelectrophilic tetrakis(carbonyl)palladium(II)- and -platinum(II) undecafluorodiantimonate(V), [Pd(CO)4][Sb(2)F(11)]2 and [Pt(CO)4][Sb(2)F(11)]2: syntheses, physical and spectroscopic properties, their crystal, molecular, and extended structures, and density functional calculations: an experimental, computational, and comparative study .

PubMed

Willner, H; Bodenbinder, M; Bröchler, R; Hwang, G; Rettig, S J; Trotter, J; von Ahsen, B; Westphal, U; Jonas, V; Thiel, W; Aubke, F

2001-01-31

The salts [M(CO)(4)][Sb(2)F(11)](2), M = Pd, Pt, are prepared by reductive carbonylation of Pd[Pd(SO(3)F)(6)], Pt(SO(3)F)(4) or PtF(6) in liquid SbF(5), or HF-SbF(5). The resulting moisture-sensitive, colorless solids are thermally stable up to 140 degrees C (M = Pd) or 200 degrees C (M = Pt). Their thermal decompositions are studied by differential scanning calorimetry (DSC). Single crystals of both salts are suitable for an X-ray diffraction study at 180 K. Both isostructural salts crystallize in the monoclinic space group P2(1)/c (No. 14). The unit cell volume of [Pt(CO)(4)][Sb(2)F(11)](2) is smaller than that of [Pd(CO)(4)][Sb(2)F(11)](2) by about 0.4%. The cations [M(CO)(4)](2+), M = Pd, Pt, are square planar with only very slight angular and out-of-plane deviations from D(4)(h)() symmetry. The interatomic distances and bond angles for both cations are essentially identical. The [Sb(2)F(11)](-) anions in [M(CO)(4)][Sb(2)F(11)](2,) M = Pd, Pt, are not symmetry-related, and both pairs differ in their Sb-F-Sb bridge angles and their dihedral angles. There are in each salt four to five secondary interionic C- -F contacts per CO group. Of these, two contacts per CO group are significantly shorter than the sum of the van der Waals radii by 0.58 - 0.37 A. In addition, structural, and spectroscopic details of recently synthesized [Rh(CO)(4)][Al(2)Cl(7)] are reported. The cations [Rh(CO)(4)](+) and [M(CO)(4)](2+), M = Pd, Pt, are characterized by IR and Raman spectroscopy. Of the 16 vibrational modes (13 observable, 3 inactive) 10 (Pd, Pt) or 9 (Rh), respectively, are found experimentally. The vibrational assignments are supported by DFT calculations, which provide in addition to band positions also intensities of IR bands and Raman signals as well as internal force constants for the cations. (13)C NMR measurements complete the characterization of the square planar metal carbonyl cations. The extensive characterization of [M(CO)(4)][Sb(2)F(11)](2), M = Pd, Pt, reported

Electronic structures of [001]- and [111]-oriented InSb and GaSb free-standing nanowires

NASA Astrophysics Data System (ADS)

Liao, Gaohua; Luo, Ning; Yang, Zhihu; Chen, Keqiu; Xu, H. Q.

2015-09-01

We report on a theoretical study of the electronic structures of InSb and GaSb nanowires oriented along the [001] and [111] crystallographic directions. The nanowires are described by atomistic, tight-binding models, including spin-orbit interaction. The band structures and the wave functions of the nanowires are calculated by means of a Lanczos iteration algorithm. For the [001]-oriented InSb and GaSb nanowires, the systems with both square and rectangular cross sections are considered. Here, it is found that all the energy bands are doubly degenerate. Although the lowest conduction bands in these nanowires show good parabolic dispersions, the top valence bands show rich and complex structures. In particular, the topmost valence bands of the nanowires with a square cross section show a double maximum structure. In the nanowires with a rectangular cross section, this double maximum structure is suppressed, and the top valence bands gradually develop into parabolic bands as the aspect ratio of the cross section is increased. For the [111]-oriented InSb and GaSb nanowires, the systems with hexagonal cross sections are considered. It is found that all the bands at the Γ-point are again doubly degenerate. However, some of them will split into non-degenerate bands when the wave vector moves away from the Γ-point. Although the lowest conduction bands again show good parabolic dispersions, the topmost valence bands do not show the double maximum structure. Instead, they show a single maximum structure with its maximum at a wave vector slightly away from the Γ-point. The wave functions of the band states near the band gaps of the [001]- and [111]-oriented InSb and GaSb nanowires are also calculated and are presented in terms of probability distributions in the cross sections. It is found that although the probability distributions of the band states in the [001]-oriented nanowires with a rectangular cross section could be qualitatively described by one-band effective

Comparison of 4'-[methyl-(11)C]thiothymidine ((11)C-4DST) and 3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) PET/CT in human brain glioma imaging.

PubMed

Toyota, Yasunori; Miyake, Keisuke; Kawai, Nobuyuki; Hatakeyama, Tetsuhiro; Yamamoto, Yuka; Toyohara, Jun; Nishiyama, Yoshihiro; Tamiya, Takashi

2015-01-01

3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) has been used to evaluate tumor malignancy and cell proliferation in human brain gliomas. However, (18)F-FLT has several limitations in clinical use. Recently, (11)C-labeled thymidine analogue, 4'-[methyl-(11)C]thiothymidine ((11)C-4DST), became available as an in vivo cell proliferation positron emission tomography (PET) tracer. The present study was conducted to evaluate the usefulness of (11)C-4DST PET in the diagnosis of human brain gliomas by comparing with the images of (18)F-FLT PET. Twenty patients with primary and recurrent brain gliomas underwent (18)F-FLT and (11)C-4DST PET scans. The uptake values in the tumors were evaluated using the maximum standardized uptake value (SUVmax), the tumor-to-normal tissue uptake (T/N) ratio, and the tumor-to-blood uptake (T/B) ratio. These values were compared among different glioma grades. Correlation between the Ki-67 labeling index and the uptake values of (11)C-4DST and (18)F-FLT in the tumor was evaluated using linear regression analysis. The relationship between the individual (18)F-FLT and (11)C-4DST uptake values in the tumors was also examined. (11)C-4DST uptake was significantly higher than that of (18)F-FLT in the normal brain. The uptake values of (11)C-4DST in the tumor were similar to those of (18)F-FLT resulting in better visualization with (18)F-FLT. No significant differences in the uptake values of (18)F-FLT and (11)C-4DST were noted among different glioma grades. Linear regression analysis showed a significant correlation between the Ki-67 labeling index and the T/N ratio of (11)C-4DST (r = 0.50, P < 0.05) and (18)F-FLT (r = 0.50, P < 0.05). Significant correlations were also found between the Ki-67 labeling index and the T/B ratio of (11)C-4DST (r = 0.52, P < 0.05) and (18)F-FLT (r = 0.55, P < 0.05). A highly significant correlation was observed between the individual T/N ratio of (11)C-4DST and (18)F-FLT in the tumor (r�

Life Testing of Yb14MnSb11 for High Performance Thermoelectric Couples

NASA Technical Reports Server (NTRS)

Paik, Jong-Ah; Brandon, Erik; Caillat, Thierry; Ewell, Richard; Fleurial, Jean-Pierre

2011-01-01

The goal of this study is to verify the long term stability of Yb14MnSb11 for high performance thermoelectric (TE) couples. Three main requirements need to be satisfied to ensure the long term stability of thermoelectric couples: 1) stable thermoelectric properties, 2) stable bonding interfaces, and 3) adequate sublimation suppression. The efficiency of the couple is primarily based on the thermoelectric properties of the materials selected for the couple. Therefore, these TE properties should exhibit minimal degradation during the operating period of the thermoelectric couples. The stability of the bonding is quantified by low contact resistances of the couple interfaces. In order to ensure high efficiency, the contact resistances of the bonding interfaces should be negligible. Sublimation suppression is important because the majority of thermoelectric materials used for power generation have peak figures of merit at temperatures where sublimation rates are high. Controlling sublimation is also essential to preserve the efficiency of the couple. During the course of this research, three different life tests were performed with Yb14MnSb11 coupons. TE properties of Yb14MnSb11 exhibited no degradation after 6 months of aging at 1273K, and the electrical contact resistance between a thin metallization layer and the Yb14MnSb11 remained negligible after 1500hr aging at 1273K. A sublimation suppression layer for Yb14MnSb11 was developed and demonstrated for more than 18 months with coupon testing at 1273K. These life test data indicate that thermoelectric elements based on Yb14MnSb11 are a promising technology for use in future high performance thermoelectric power generating couples.

40 CFR 721.10175 - 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18 and C18-unsatd...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 1-Propanaminium, N-(3-aminopropyl)-2... 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18 and C18-unsatd. acyl... chemical substance identified as 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12...

40 CFR 721.642 - Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... substances amines, N-(C14-18 and C16-18 unsaturated alkyl)] dipropylenetri-, (PMN P-94-1244... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amines, N-(C14-18 and C16-16... Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and...

Behavior of GaSb (100) and InSb (100) surfaces in the presence of H2O2 in acidic and basic cleaning solutions

NASA Astrophysics Data System (ADS)

Seo, Dongwan; Na, Jihoon; Lee, Seunghyo; Lim, Sangwoo

2017-03-01

Gallium antimonide (GaSb) and indium antimonide (InSb) have attracted strong attention as new channel materials for transistors due to their excellent electrical properties and lattice matches with various group III-V compound semiconductors. In this study, the surface behavior of GaSb (100) and InSb (100) was investigated and compared in hydrochloric acid/hydrogen peroxide mixture (HPM) and ammonium hydroxide/hydrogen peroxide mixture (APM) solutions. In the acidic HPM solution, surface oxidation was greater and the etching rates of the GaSb and InSb surfaces increased when the solution is concentrated, which indicates that H2O2 plays a key role in the surface oxidation of GaSb and InSb in acidic HPM solution. However, the GaSb and InSb surfaces were hardly oxidized in basic APM solution in the presence of H2O2 because gallium and indium are in the thermodynamically stable forms of H2GaO3- and InO2-, respectively. When the APM solution was diluted, however, the Ga on the GaSb surface was oxidized by H2O, increasing the etching rate. However, the effect of dilution of the APM solution on the oxidation of the InSb surface was minimal; thus, the InSb surface was less oxidized than the GaSb surface and the change in the etching rate of InSb with dilution of the APM solution was not significant. Additionally, the oxidation behavior of gallium and indium was more sensitive to the composition of the HPM and APM solutions than that of antimony. Therefore, the surface properties and etching characteristics of GaSb and InSb in HPM and APM solutions are mainly dependent on the behavior of the group III elements rather than the group V elements.

Structural, electronic, and thermal properties of indium-filled InxIr4Sb12 skutterudites

NASA Astrophysics Data System (ADS)

Wallace, M. K.; Li, Jun; Subramanian, M. A.

2018-06-01

The "phonon-glass/electron-crystal" approach has been implemented through incorporation of "rattlers" into skutterudite void sites to increase phonon scattering and thus increase the thermoelectric efficiency. Indium filled IrSb3 skutterudites are reported for the first time. Polycrystalline samples of InxIr4Sb12 (0 ≤ x ≤ 0.2) were prepared by solid-state reaction under a gas mixture of 5% H2 and 95% Ar. The solubility limit of InxIr4Sb12 was found to be close to 0.18. Synchrotron X-ray diffraction refinements reveal all InxIr4Sb12 phases crystallized in body-centered cubic structure (space group : Im 3 bar) with ∼8% antimony site vacancy and with indium partially occupying the 16f site. Unlike known rattler filled skutterudites, under synthetic conditions employed, indium filling in IrSb3 significantly increases the electrical resistivity and decreases the Seebeck coefficient (n-type) while reducing the thermal conductivity by ∼30%. The resultant power factor offsets the decrease in total thermal conductivity giving rise to a substantial decrease in ZT. Principal thermoelectric properties of InxM4Sb12 (M = Co, Rh, Ir) phases are compared. As iridium is a 5d transition metal, zero field cooled (ZFC) magnetization were performed to unravel the effect of spin-orbit interaction on the electronic properties. These results serve to advance the understanding of filled skutterudites, and provide additional insight on the less explored smaller "rattlers" and their influence on key thermoelectric properties.

Effect of in situ annealing on the structural and electrical properties and infrared photodetection of III-Sb on GaAs using interfacial misfit array

NASA Astrophysics Data System (ADS)

Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt

2018-01-01

This work presents the effects of in situ thermal annealing under antimony overpressure on the structural, electrical, and optical properties of III-Sb (GaSb and InSb) grown on (100) GaAs using an interfacial misfit array to accommodate the lattice mismatch. Both the sample growth and the in situ thermal annealing were carried out in the in the molecular beam epitaxy system, and the temperature of the as-grown sample was increased to exceed its growth temperature during the annealing. X-ray diffraction demonstrates nearly fully relaxed as-grown and annealed III-Sb layers. The optimal annealing temperatures and durations are for 590 °C, 5 min for GaSb and 420 °C, 15 min for InSb, respectively. In situ annealing decreased the surface roughness of the III-Sb layers. X-ray reciprocal space mapping and transmission electron microscopy observation showed stable interfacial misfit arrays, and no interfacial diffusion occurred in the annealed III-Sb layers. A Hall measurement of unintentionally doped III-Sb layers showed greater carrier mobility and a lower carrier concentration in the annealed samples at both 77 and 300 K. In situ annealing improved the photoresponsivity of GaSb and InSb photoconductors grown on GaAs in the near- and mid-infrared ranges, respectively.

Low-Temperature Atomic Layer Deposition of CuSbS2 for Thin-Film Photovoltaics.

PubMed

Riha, Shannon C; Koegel, Alexandra A; Emery, Jonathan D; Pellin, Michael J; Martinson, Alex B F

2017-02-08

Copper antimony sulfide (CuSbS 2 ) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (∼1.5 eV), large absorption coefficient (>10 4 cm -1 ), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbS 2 thin films via atomic layer deposition has been developed. After a short (15 min) postprocess anneal at 225 °C, the ALD-grown CuSbS 2 films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >10 4 cm -1 , as well as a hole concentration of 10 15 cm -3 . Finally, the ALD-grown CuSbS 2 films were paired with ALD-grown TiO 2 to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbS 2 PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbS 2 /CdS heterojunction PV devices. While far from optimized, this work demonstrates the potential for ALD-grown CuSbS 2 thin films in environmentally benign photovoltaics.

Low-temperature atomic layer deposition of CuSbS 2 for thin-film photovoltaics

DOE PAGES

Riha, Shannon C.; Koegel, Alexandra A.; Emery, Jonathan D.; ...

2017-01-24

Copper antimony sulfide (CuSbS 2) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (~1.5 eV), large absorption coefficient (>10 4 cm –1), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbS 2 thin films via atomic layer deposition has been developed. After a short (15 min) post process anneal at 225 °C, the ALD-grown CuSbS 2 films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >10 4 cm –1, as wellmore » as a hole concentration of 10 15 cm –3. Finally, the ALD-grown CuSbS 2 films were paired with ALD-grown TiO 2 to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbS 2 PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbS 2/CdS heterojunction PV devices. As a result, while far from optimized, this work demonstrates the potential for ALD-grown CuSbS 2 thin films in environmentally benign photovoltaics.« less

Stibiconite (Sb3O6OH), senarmontite (Sb2O3) and valentinite (Sb2O3): Dissolution rates at pH 2-11 and isoelectric points

NASA Astrophysics Data System (ADS)

Biver, M.; Shotyk, W.

2013-05-01

Batch reactor experiments were carried out in order to derive rate laws for the proton promoted dissolution of the main natural antimony oxide phases, namely stibiconite (idealized composition SbSb2O6OH), senarmontite (cubic Sb2O3) and (metastable) valentinite (orthorhombic Sb2O3) over the range 2 ⩽ pH ⩽ 11, under standard conditions and ionic strength I = 0.01 mol l-1. The rates of antimony release by stibiconite were r = (2.2 ± 0.2) × 10-9 a(H+)0.11±0.01 mol m-2 s-1 for 2.00 ⩽ pH ⩽ 4.74 and r = (4.3 ± 0.2) × 10-10 a(H+)-0.030±0.003 mol m-2 s-1 for 4.74 ⩽ pH ⩽ 10.54. The rates of dissolution of senarmontite were r = (5.3 ± 2.2) × 10-7 a(H+)0.54±0.05 mol m-2 s-1 for 2.00 ⩽ pH ⩽ 6.93 and r = (1.4 ± 0.3) × 10-14 a(H+)-0.53±0.07 mol m-2 s-1 for 6.93 ⩽ pH ⩽ 10.83. The rates of dissolution of valentinite were r = (6.3 ± 0.2) × 10-8 a(H+)0.052±0.003 mol m-2 s-1 for 1.97 ⩽ pH ⩽ 6.85. Above pH = 6.85, valentinite was found to dissolve at a constant rate of r = (2.79 ± 0.05) × 10-8 mol m-2 s-1. Activation energies were determined at selected pH values in the acidic and basic domain, over the temperature range 25-50 °C. The values for stibiconite are -10.6 ± 1.9 kJ mol-1 (pH = 2.00) and 53 ± 14 kJ mol-1 (pH = 8.7). For senarmontite, we found 46.6 ± 4.7 kJ mol-1 (pH = 3.0) and 68.1 ± 6.1 kJ mol-1 (pH = 9.9) and for valentinite 41.9 ± 1.1 kJ mol-1 (pH = 3.0) and 39.0 ± 4.6 kJ mol-1 (pH = 9.9). These activation energies are interpreted in the text. The solubility of stibiconite at 25 °C in the pH domain from 2 to 10 was determined; solubilities decrease from 452.0 μg l-1 (as Sb) at pH = 2.00 to 153.2 μg l-1 at pH = 7.55 and increase again in the basic region, up to 176.6 μg l-1 at pH = 9.92. A graphical synopsis of all the kinetic results, including those of stibnite (Sb2S3) from earlier work, is presented. This allows an easy comparison between the dissolution rates of stibnite and the minerals examined in the present work

PathCase-SB architecture and database design

PubMed Central

2011-01-01

Background Integration of metabolic pathways resources and regulatory metabolic network models, and deploying new tools on the integrated platform can help perform more effective and more efficient systems biology research on understanding the regulation in metabolic networks. Therefore, the tasks of (a) integrating under a single database environment regulatory metabolic networks and existing models, and (b) building tools to help with modeling and analysis are desirable and intellectually challenging computational tasks. Description PathCase Systems Biology (PathCase-SB) is built and released. The PathCase-SB database provides data and API for multiple user interfaces and software tools. The current PathCase-SB system provides a database-enabled framework and web-based computational tools towards facilitating the development of kinetic models for biological systems. PathCase-SB aims to integrate data of selected biological data sources on the web (currently, BioModels database and KEGG), and to provide more powerful and/or new capabilities via the new web-based integrative framework. This paper describes architecture and database design issues encountered in PathCase-SB's design and implementation, and presents the current design of PathCase-SB's architecture and database. Conclusions PathCase-SB architecture and database provide a highly extensible and scalable environment with easy and fast (real-time) access to the data in the database. PathCase-SB itself is already being used by researchers across the world. PMID:22070889

GaSb solar cells grown on GaAs via interfacial misfit arrays for use in the III-Sb multi-junction cell

NASA Astrophysics Data System (ADS)

Nelson, George T.; Juang, Bor-Chau; Slocum, Michael A.; Bittner, Zachary S.; Laghumavarapu, Ramesh B.; Huffaker, Diana L.; Hubbard, Seth M.

2017-12-01

Growth of GaSb with low threading dislocation density directly on GaAs may be possible with the strategic strain relaxation of interfacial misfit arrays. This creates an opportunity for a multi-junction solar cell with access to a wide range of well-developed direct bandgap materials. Multi-junction cells with a single layer of GaSb/GaAs interfacial misfit arrays could achieve higher efficiency than state-of-the-art inverted metamorphic multi-junction cells while forgoing the need for costly compositionally graded buffer layers. To develop this technology, GaSb single junction cells were grown via molecular beam epitaxy on both GaSb and GaAs substrates to compare homoepitaxial and heteroepitaxial GaSb device results. The GaSb-on-GaSb cell had an AM1.5g efficiency of 5.5% and a 44-sun AM1.5d efficiency of 8.9%. The GaSb-on-GaAs cell was 1.0% efficient under AM1.5g and 4.5% at 44 suns. The lower performance of the heteroepitaxial cell was due to low minority carrier Shockley-Read-Hall lifetimes and bulk shunting caused by defects related to the mismatched growth. A physics-based device simulator was used to create an inverted triple-junction GaInP/GaAs/GaSb model. The model predicted that, with current GaSb-on-GaAs material quality, the not-current-matched, proof-of-concept cell would provide 0.5% absolute efficiency gain over a tandem GaInP/GaAs cell at 1 sun and 2.5% gain at 44 suns, indicating that the effectiveness of the GaSb junction was a function of concentration.

Native point defects in GaSb

NASA Astrophysics Data System (ADS)

Kujala, J.; Segercrantz, N.; Tuomisto, F.; Slotte, J.

2014-10-01

We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude. We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.

17 CFR 240.15c1-8 - Sales at the market.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Sales at the market. 240.15c1-8 Section 240.15c1-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Securities Exchange Act of 1934 Rules Relating to Over-The-Counter Markets § 240.15c1-8 Sales at the market...

Building Planner Commitment : Are California's SB 375 and Oregon's SB 1059 Models for Climate-Change Mitigation?

DOT National Transportation Integrated Search

2017-11-01

California's Sustainable Communities and Climate Protection Act (SB 375) and the Oregon Sustainable Transportation Initiative (SB 1059) have made them the first states in the nation to try and reduce greenhouse gas (GHG) emissions using the transport...

Sb-Te alloy nanostructures produced on a graphite surface by a simple annealing process

NASA Astrophysics Data System (ADS)

Kuwahara, Masashi; Uratsuji, Hideaki; Abe, Maho; Sone, Hayato; Hosaka, Sumio; Sakai, Joe; Uehara, Yoichi; Endo, Rie; Tsuruoka, Tohru

2015-08-01

We have produced Sb-Te alloy nanostructures from a thin Sb2Te3 layer deposited on a highly oriented pyrolytic graphite substrate using a simple rf-magnetron sputtering and annealing technique. The size, shape, and chemical composition of the structures were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectrometry (EDX), respectively. The shape of the nanostructures was found to depend on the annealing temperature; nanoparticles appear on the substrate by annealing at 200 °C, while nanoneedles are formed at higher temperatures. Chemical composition analysis has revealed that all the structures were in the composition of Sb:Te = 1:3, Te rich compared to the target composition Sb2Te3, probably due to the higher movability of Te atoms on the substrate compared with Sb. We also tried to observe the production process of nanostructures in situ using SEM. Unfortunately, this was not possible because of evaporation in vacuum, suggesting that the formation of nanostructures is highly sensitive to the ambient pressure.

Photoconductivity in the chalcohalide semiconductor, SbSeI: a new candidate for hard radiation detection.

PubMed

Wibowo, Arief C; Malliakas, Christos D; Liu, Zhifu; Peters, John A; Sebastian, Maria; Chung, Duck Young; Wessels, Bruce W; Kanatzidis, Mercouri G

2013-06-17

We investigated an antimony chalcohalide compound, SbSeI, as a potential semiconductor material for X-ray and γ-ray detection. SbSeI has a wide band gap of 1.70 eV with a density of 5.80 g/cm(3), and it crystallizes in the orthorhombic Pnma space group with a one-dimensional chain structure comprised of infinite zigzag chains of dimers [Sb2Se4I8]n running along the crystallographic b axis. In this study, we investigate conditions for vertical Bridgman crystal growth using combinations of the peak temperature and temperature gradients as well as translation rate set in a three-zone furnace. SbSeI samples grown at 495 °C peak temperature and 19 °C/cm temperature gradient with 2.5 mm/h translation rate produced a single phase of columnar needlelike crystals aligned along the translational direction of the growth. The ingot sample exhibited an n-type semiconductor with resistivity of ∼10(8) Ω·cm. Photoconductivity measurements on these specimens allowed us to determine mobility-lifetime (μτ) products for electron and hole carriers that were found to be of similar order of magnitude (∼10(-4) cm(2)/V). Further, the SbSeI ingot with well-aligned, one-dimensional columnar needlelike crystals shows an appreciable response of Ag Kα X-ray.

Electronic structures of [001]- and [111]-oriented InSb and GaSb free-standing nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liao, Gaohua; Department of Applied Physics and Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha 410082; Luo, Ning

We report on a theoretical study of the electronic structures of InSb and GaSb nanowires oriented along the [001] and [111] crystallographic directions. The nanowires are described by atomistic, tight-binding models, including spin-orbit interaction. The band structures and the wave functions of the nanowires are calculated by means of a Lanczos iteration algorithm. For the [001]-oriented InSb and GaSb nanowires, the systems with both square and rectangular cross sections are considered. Here, it is found that all the energy bands are doubly degenerate. Although the lowest conduction bands in these nanowires show good parabolic dispersions, the top valence bands showmore » rich and complex structures. In particular, the topmost valence bands of the nanowires with a square cross section show a double maximum structure. In the nanowires with a rectangular cross section, this double maximum structure is suppressed, and the top valence bands gradually develop into parabolic bands as the aspect ratio of the cross section is increased. For the [111]-oriented InSb and GaSb nanowires, the systems with hexagonal cross sections are considered. It is found that all the bands at the Γ-point are again doubly degenerate. However, some of them will split into non-degenerate bands when the wave vector moves away from the Γ-point. Although the lowest conduction bands again show good parabolic dispersions, the topmost valence bands do not show the double maximum structure. Instead, they show a single maximum structure with its maximum at a wave vector slightly away from the Γ-point. The wave functions of the band states near the band gaps of the [001]- and [111]-oriented InSb and GaSb nanowires are also calculated and are presented in terms of probability distributions in the cross sections. It is found that although the probability distributions of the band states in the [001]-oriented nanowires with a rectangular cross section could be qualitatively described by one

Composition dependence of band alignments in GaxIn1-xAsySb1-y heterojunctions lattice matched to GaSb and InAs

NASA Astrophysics Data System (ADS)

Shim, Kyurhee

2013-11-01

A theoretical model utilizing a universal tight binding method and a correlated function expansion technique is presented to calculate the valence band maximum (VBM) and the conduction band minimum (CBM) of the binary (GaAs, InAS, GaSb, and InSb) and quaternary alloy GaxIn1-xAsySb1-y systems. By organizing the relative positions of the VBM and CBM between semiconductors, the band alignments and band types in the heterojunctions are determined. A straddling (type-I) band alignment in InAs/GaAs, InSb/GaAs, and GaSb/InSb, staggered (type-II) band alignment in GaSb/GaAs, and broken (type-III) band alignment in InSb/InAs and InAs/GaSb are found respectively. In addition, the compositional variations of VBM, CBM, valence band offset, conduction band offset, and band type for the alloy GaxIn1-xAsySb1-y lattice matched on GaSb and InAs are obtained as increasing the composition x. A pronounced upward bowing for the VBM and a very slight upward bowing (almost linear) for CBM are found, respectively. By controlling the compositions (x, y), band type transitions occur. The GaxIn1-xAsySb1-y heterojunctions lattice matched to GaSb changes their band types from type-III at x ˜0→ to type-II at x = 0.07, and → to type-I at x = 0.38. In contrast, the GaxIn1-xAsySb1-y heterojunctions lattice matched to InAs changes their band types from type-II x ˜0→ to type-III at x = 0.32. Reasonable agreement is obtained between our theoretical results and existing experimental data.

Surface Phase Stability and Surfactant Behavior on InAsSb

NASA Astrophysics Data System (ADS)

Anderson, Evan M.

InAsSb and related III-As/III-Sb heterostructures are of technological interest for applications in long wavelength infrared optoelectronic devices. However, there remain challenges to growing high quality material for these devices due to the complex interaction between As and Sb. While this interaction has been the subject of intense study, little work has focused on how As and Sb behave at the material surface with even fewer investigations into the atomic scale details of the InAsSb surface. This is a major gap in current knowledge because these materials are typically grown via vapor deposition methods, one atomic layer at a time. Thus, all processes impacting the growth of the crystal and its resultant properties occur at the surface. Despite this, the atomic scale details of the surface phases and processes impacting the Sb-As interaction have not previously been reported. This dissertation investigates the surface As-Sb interaction at an atomistic scale and its modification through different surface chemistry to be used as a guide for future experiments to improve the quality InAsSb of heterostructures by manipulating the surface phase during growth. In order to accomplish this, first principles calculations and experiments are used to investigate this system from three complimentary vantage points. First, the influence of Sb on the InAs surface and the stable surface phases of this system are investigated. Next, a similar approach is used on the opposite compositional extreme of the InAsSb system: As on the surface of InSb. Finally, the interaction of As and Sb is modified by the use of Bi as a surfactant during growth of InAsSb films. The interaction between As and Sb is found to be driven through the formation of surface phases and Bi is found to alter this interaction. Phase diagrams of both Sb on InAs and As on InSb show that As and Sb are driven to intermix through the formation of alloyed surface phases. Additionally, these phases range from having

Effect of Sb in thick InGaAsSbN layers grown by liquid phase epitaxy

NASA Astrophysics Data System (ADS)

Donchev, V.; Milanova, M.; Asenova, I.; Shtinkov, N.; Alonso-Álvarez, D.; Mellor, A.; Karmakov, Y.; Georgiev, S.; Ekins-Daukes, N.

2018-02-01

Dilute nitride InGaAsSbN layers grown by low-temperature liquid phase epitaxy are studied in comparison with quaternary InGaAsN layers grown at the same growth conditions to understand the effect of Sb in the alloy. The lattice mismatch to the GaAs substrate is found to be slightly larger for the InGaAsSbN layers, which is explained by the large atomic radius of Sb. A reduction of the band gap energy with respect to InGaAsN is demonstrated by means of photoluminescence (PL), surface photovoltage (SPV) spectroscopy and tight-binding calculations. The band-gap energies determined from PL and ellipsometry measurements are in good agreement, while the SPV spectroscopy and the tight-binding calculations provide lower values. Possible reasons for these discrepancies are discussed. The PL spectra reveal localized electronic states in the band gap near the conduction band edge, which is confirmed by SPV spectroscopy. The analysis of the power dependence of the integrated PL has allowed determining the dominant radiative recombination mechanisms in the layers. The values of the refraction index in a wide spectral region are found to be higher for the Sb containing layers.

Nearly massless Dirac fermions hosted by Sb square net in BaMnSb2

PubMed Central

Liu, Jinyu; Hu, Jin; Cao, Huibo; Zhu, Yanglin; Chuang, Alyssa; Graf, D.; Adams, D. J.; Radmanesh, S. M. A.; Spinu, L.; Chiorescu, I.; Mao, Zhiqiang

2016-01-01

Layered compounds AMnBi2 (A = Ca, Sr, Ba, or rare earth element) have been established as Dirac materials. Dirac electrons generated by the two-dimensional (2D) Bi square net in these materials are normally massive due to the presence of a spin-orbital coupling (SOC) induced gap at Dirac nodes. Here we report that the Sb square net in an isostructural compound BaMnSb2 can host nearly massless Dirac fermions. We observed strong Shubnikov-de Haas (SdH) oscillations in this material. From the analyses of the SdH oscillations, we find key signatures of Dirac fermions, including light effective mass (~0.052m0; m0, mass of free electron), high quantum mobility (1280 cm2V−1S−1) and a π Berry phase accumulated along cyclotron orbit. Compared with AMnBi2, BaMnSb2 also exhibits much more significant quasi two-dimensional (2D) electronic structure, with the out-of-plane transport showing nonmetallic conduction below 120 K and the ratio of the out-of-plane and in-plane resistivity reaching ~670. Additionally, BaMnSb2 also exhibits a G-type antiferromagnetic order below 283 K. The combination of nearly massless Dirac fermions on quasi-2D planes with a magnetic order makes BaMnSb2 an intriguing platform for seeking novel exotic phenomena of massless Dirac electrons. PMID:27466151

Modelling of the Sb and N distribution in type II GaAsSb/GaAsN superlattices for solar cell applications

NASA Astrophysics Data System (ADS)

Reyes, D. F.; Braza, V.; Gonzalo, A.; Utrilla, A. D.; Ulloa, J. M.; Ben, T.; González, D.

2018-06-01

GaAsSbN dilute nitrides are potential candidates for integration in high-performance multi-junction solar cells due to the bandgap tunability in the 1.0-1.15 eV range and the possibility to match the lattice constant to the GaAs substrates. Recently, the use of GaAsSb/GaAsN superlattices (SLs) has been shown as an effective way to enhance photovoltaic efficiency as compared to the quaternary counterparts. Here we apply a combination of HR-XRD and cross-sectional (S)TEM techniques together with theoretical calculations to analyse the compositional distribution in GaAsSb/GaAsN SLs with different periodicity. The measurements of compositional profiles indicate that Sb is strongly segregated into the GaAsN layers while N remains confined where it is deposited. We demonstrate that the Sb profiles run as a shark-fin waveform that can be precisely described with a one-dimensional model where segregation of the supplied Sb is promoted by a three-layer fluid exchange mechanism. Moreover, the role played by the periodicity in the effectiveness of the Sb incorporation adds a new level of complexity. The modelling of Sb segregation in the GaAsSb/GaAsN SLs system could be used to carry out more precise pseudopotential calculations on the band structure in order to understand and predict their electrical and optical behaviour.

Room temperature operation of mid-infrared InAs0.81Sb0.19 based photovoltaic detectors with an In0.2Al0.8Sb barrier layer grown on GaAs substrates.

PubMed

Geum, Dae-Myeong; Kim, SangHyeon; Kang, SooSeok; Kim, Hosung; Park, Hwanyeol; Rho, Il Pyo; Ahn, Seung Yeop; Song, Jindong; Choi, Won Jun; Yoon, Euijoon

2018-03-05

In this paper, InAs 0.81 Sb 0.19 -based hetero-junction photovoltaic detector (HJPD) with an In 0.2 Al 0.8 Sb barrier layer was grown on GaAs substrates. By using technology computer aided design (TCAD), a design of a barrier layer that can achieve nearly zero valance band offsets was accomplished. A high quality InAs 0.81 Sb 0.19 epitaxial layer was obtained with relatively low threading dislocation density (TDD), calculated from a high-resolution X-ray diffraction (XRD) measurement. This layer showed a Hall mobility of 15,000 cm 2 /V⋅s, which is the highest mobility among InAsSb layers with an Sb composition of around 20% grown on GaAs substrates. Temperature dependence of dark current, photocurrent response and responsivity were measured and analyzed for fabricated HJPD. HJPD showed the clear photocurrent response having a long cutoff wavelength of 5.35 μm at room temperature. It was observed that the dark current of HJPDs is dominated by the diffusion limited current at temperatures ranging from 200K to room temperature from the dark current analysis. Peak responsivity of HJPDs exhibited the 1.18 A/W and 15 mA/W for 83K and a room temperature under zero bias condition even without anti-reflection coating (ARC). From these results, we believe that HJPDs could be an appropriate PD device for future compact and low power dissipation mid-infrared on-chip sensors and imaging devices.

Improved mechanical properties of thermoelectric (Bi 0.2Sb 0.8) 2Te 3 by nanostructuring

DOE PAGES

Lavrentev, M. G.; Osvenskii, V. B.; Parkhomenko, Yu. N.; ...

2016-06-01

Temperature-dependent strength of Bi-Sb-Te under uniaxial compression is investigated. Bi-Sb-Te samples were produced by three methods: vertical zone-melting, hot extrusion, and spark plasma sintering (SPS). For zone-melted and extruded samples, the brittle-ductile transition occurs over a temperature range of 200-350 °C. In nanostructured samples produced via SPS, the transition is observed in a narrower temperature range of 170-200 °C. At room temperature, the strength of the nanostructured samples is higher than that of zone-melted and extruded samples, but above 300 °C, all samples decrease to roughly the same strength.

Improved mechanical properties of thermoelectric (Bi 0.2Sb 0.8) 2Te 3 by nanostructuring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavrentev, M. G.; Osvenskii, V. B.; Parkhomenko, Yu. N.

Temperature-dependent strength of Bi-Sb-Te under uniaxial compression is investigated. Bi-Sb-Te samples were produced by three methods: vertical zone-melting, hot extrusion, and spark plasma sintering (SPS). For zone-melted and extruded samples, the brittle-ductile transition occurs over a temperature range of 200-350 °C. In nanostructured samples produced via SPS, the transition is observed in a narrower temperature range of 170-200 °C. At room temperature, the strength of the nanostructured samples is higher than that of zone-melted and extruded samples, but above 300 °C, all samples decrease to roughly the same strength.

Native point defects in GaSb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kujala, J.; Segercrantz, N.; Tuomisto, F.

2014-10-14

We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude.more » We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.« less

Capsule endoscopy with PillCamSB2 versus PillCamSB3: has the improvement in technology resulted in a step forward?

PubMed

Xavier, Sofia; Monteiro, Sara; Magalhães, Joana; Rosa, Bruno; Moreira, Maria João; Cotter, José

2018-03-01

To compare the findings and completion rate of PillCam® SB2 and SB3. This was a retrospective single-center study that included 357 consecutive small bowel capsule endoscopies (SBCE), 173 SB2 and 184 SB3. The data collected included age, gender, capsule type (PillCam® SB2 or SB3), quality of bowel preparation, completion of the examination, gastric and small bowel transit time, small bowel findings, findings in segments other than the small bowel and the detection of specific anatomical markers, such as the Z line and papilla. The mean age of the patients was 48 years and 66.9% were female. The two main indications were suspicion/staging of inflammatory bowel disease (IBD) and obscure gastrointestinal bleeding (OGIB) (43.7% and 40.3%, respectively). Endoscopic findings were reported in 76.2% of examinations and 53.5% were relevant findings. No significant differences were found between SB2 and SB3 with regard to completion rate (93.6% vs 96.2%, p = 0.27), overall endoscopic findings (73.4% vs 78.8%, p = 0.23), relevant findings (54.3% vs 52.7%, p = 0.76), first tertile findings (43.9% vs 48.9%, p = 0.35), extra-SB findings (23.7% vs 17.3%, p = 0.14), Z line and papilla detection rate (35.9% vs 35.7%, p = 0.97 and 27.1% vs 32.6%, p = 0.32, respectively). With regard to the patient subgroups with suspicion/staging of IBD, significant differences were found in relation to the detection of villous edema and the 3rd tertile findings, thus favoring SB3 (26.3% vs 43.8%, p = 0.02 and 47.4% vs 66.3%, p = 0.02, respectively). Mucosal atrophy was significantly more frequently diagnosed with the PillCam® SB3 in patients with anemia/OGIB (0% vs 8%, p = 0.03). Overall, PillCam® SB3 did not improve the diagnostic yield compared to SB2, although it improved the detection of villous atrophy and segmental edema.

Limits on superconductivity-related magnetization in Sr 2RuO 4 and PrOs 4Sb 12 from scanning SQUID microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moler, Kathryn

2010-08-26

We present scanning SQUID microscopy data on the superconductors Sr{sub 2}RuO{sub 4} (T{sub c} = 1.5 K) and PrOs{sub 4}Sb{sub 12} (T{sub c} = 1.8 K). In both of these materials, superconductivity-related time-reversal symmetry-breaking fields have been observed by muon spin rotation; our aim was to visualize the structure of these fields. However in neither Sr{sub 2}RuO{sub 4} nor PrOs{sub 4}Sb{sub 12} do we observe spontaneous superconductivity-related magnetization. In Sr{sub 2}RuO{sub 4}, many experimental results have been interpreted on the basis of a p{sub x} {+-} ip{sub y} superconducting order parameter. This order parameter is expected to give spontaneous magneticmore » induction at sample edges and order parameter domain walls. Supposing large domains, our data restrict domain wall and edge fields to no more than {approx}0.1% and {approx}0.2% of the expected magnitude, respectively. Alternatively, if the magnetization is of the expected order, the typical domain size is limited to {approx}30 nm for random domains, or {approx} 500 nm for periodic domains.« less

Pressure induced structural transitions in CuSbS 2 and CuSbSe 2 thermoelectric compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Jason; Kumar, Ravhi S.; Sneed, Daniel

Here, we investigate the structural behavior of CuSbS 2 and CuSbSe 2 thermoelectric materials under high pressure conditions up to 80 GPa using angle dispersive X-ray diffraction in a diamond anvil cell (DAC). We also perform high pressure Raman spectroscopy measurements up to 16 GPa. We observed a pressure-induced structural transformation from the ambient orthorhombic structure with space group Pnma to a triclinic type structure with space group P1 beginning around 8 GPa in both samples and completing at 13 GPa and 10 GPa in CuSbS 2 and CuSbSe 2, respectively. High pressure Raman experiments complement the transitions observed bymore » high pressure X-ray diffraction (HPXRD). Finally, the transitions were found to be reversible on releasing the pressure to ambient in the DAC. The bulk modulus and compressibility of these materials are further discussed.« less

Pressure induced structural transitions in CuSbS 2 and CuSbSe 2 thermoelectric compounds

DOE PAGES

Baker, Jason; Kumar, Ravhi S.; Sneed, Daniel; ...

2015-04-27

Here, we investigate the structural behavior of CuSbS 2 and CuSbSe 2 thermoelectric materials under high pressure conditions up to 80 GPa using angle dispersive X-ray diffraction in a diamond anvil cell (DAC). We also perform high pressure Raman spectroscopy measurements up to 16 GPa. We observed a pressure-induced structural transformation from the ambient orthorhombic structure with space group Pnma to a triclinic type structure with space group P1 beginning around 8 GPa in both samples and completing at 13 GPa and 10 GPa in CuSbS 2 and CuSbSe 2, respectively. High pressure Raman experiments complement the transitions observed bymore » high pressure X-ray diffraction (HPXRD). Finally, the transitions were found to be reversible on releasing the pressure to ambient in the DAC. The bulk modulus and compressibility of these materials are further discussed.« less

Photophysical Property and Photocatalytic Activity of New Gd2InSbO7 and Gd2FeSbO7 Compounds under Visible Light Irradiation

PubMed Central

Luan, Jingfei; Xu, Yong

2013-01-01

Gd2InSbO7 and Gd2FeSbO7 were synthesized first, and their structural and photocatalytic properties were studied. The lattice parameters and the band gaps for Gd2InSbO7 and Gd2FeSbO7 were 10.449546 Å, 10.276026 Å, 2.897 eV and 2.151 eV. The photocatalytic degradation of rhodamine B was performed with Gd2InSbO7 and Gd2FeSbO7 under visible light irradiation. Gd2InSbO7 and Gd2FeSbO7 had higher catalytic activity compared with Bi2InTaO7. Gd2FeSbO7 exhibited higher catalytic activity than Gd2InSbO7. The photocatalytic degradation of rhodamine B followed with the first-order reaction kinetics, and the first-order rate constant k was 0.01606, 0.02220 or 0.00329 min−1 with Gd2InSbO7, Gd2FeSbO7 or Bi2InTaO7 as photocatalyst. Complete removal of rhodamine B was observed after visible light irradiation for 225 min or 260 min with Gd2FeSbO7 or Gd2InSbO7 as photocatalyst. The evolution of CO2 was realized, and it indicated continuous mineralization of rhodamine B during the photocatalytic process. The possible photocatalytic degradation pathway of rhodamine B was proposed. PMID:23296275

Carbon-doped Ge2Sb2Te5 phase change material: A candidate for high-density phase change memory application

NASA Astrophysics Data System (ADS)

Zhou, Xilin; Wu, Liangcai; Song, Zhitang; Rao, Feng; Zhu, Min; Peng, Cheng; Yao, Dongning; Song, Sannian; Liu, Bo; Feng, Songlin

2012-10-01

Carbon-doped Ge2Sb2Te5 material is proposed for high-density phase-change memories. The carbon doping effects on electrical and structural properties of Ge2Sb2Te5 are studied by in situ resistance and x-ray diffraction measurements as well as optical spectroscopy. C atoms are found to significantly enhance the thermal stability of amorphous Ge2Sb2Te5 by increasing the degree of disorder of the amorphous phase. The reversible electrical switching capability of the phase-change memory cells is improved in terms of power consumption with carbon addition. The endurance of ˜2.1 × 104 cycles suggests that C-doped Ge2Sb2Te5 film will be a potential phase-change material for high-density storage application.

Electrical characteristics and thermal stability of HfO{sub 2} metal-oxide-semiconductor capacitors fabricated on clean reconstructed GaSb surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyata, Noriyuki, E-mail: nori.miyata@aist.go.jp; Mori, Takahiro; Yasuda, Tetsuji

2014-06-09

HfO{sub 2}/GaSb interfaces fabricated by high-vacuum HfO{sub 2} deposition on clean reconstructed GaSb surfaces were examined to explore a thermally stable GaSb metal-oxide-semiconductor structure with low interface-state density (D{sub it}). Interface Sb-O bonds were electrically and thermally unstable, and post-metallization annealing at temperatures higher than 200 °C was required to stabilize the HfO{sub 2}/GaSb interfaces. However, the annealing led to large D{sub it} in the upper-half band gap. We propose that the decomposition products that are associated with elemental Sb atoms act as interface states, since a clear correlation between the D{sub it} and the Sb coverage on the initial GaSbmore » surfaces was observed.« less

Impact of N on the atomic-scale Sb distribution in quaternary GaAsSbN-capped InAs quantum dots

PubMed Central

2012-01-01

The use of GaAsSbN capping layers on InAs/GaAs quantum dots (QDs) has recently been proposed for micro- and optoelectronic applications for their ability to independently tailor electron and hole confinement potentials. However, there is a lack of knowledge about the structural and compositional changes associated with the process of simultaneous Sb and N incorporation. In the present work, we have characterized using transmission electron microscopy techniques the effects of adding N in the GaAsSb/InAs/GaAs QD system. Firstly, strain maps of the regions away from the InAs QDs had revealed a huge reduction of the strain fields with the N incorporation but a higher inhomogeneity, which points to a composition modulation enhancement with the presence of Sb-rich and Sb-poor regions in the range of a few nanometers. On the other hand, the average strain in the QDs and surroundings is also similar in both cases. It could be explained by the accumulation of Sb above the QDs, compensating the tensile strain induced by the N incorporation together with an In-Ga intermixing inhibition. Indeed, compositional maps of column resolution from aberration-corrected Z-contrast images confirmed that the addition of N enhances the preferential deposition of Sb above the InAs QD, giving rise to an undulation of the growth front. As an outcome, the strong redshift in the photoluminescence spectrum of the GaAsSbN sample cannot be attributed only to the N-related reduction of the conduction band offset but also to an enhancement of the effect of Sb on the QD band structure. PMID:23181950

Synthesis and structural characterization of bulk Sb2Te3 single crystal

NASA Astrophysics Data System (ADS)

Sultana, Rabia; Gahtori, Bhasker; Meena, R. S.; Awana, V. P. S.

2018-05-01

We report the growth and characterization of bulk Sb2Te3 single crystal synthesized by the self flux method via solid state reaction route from high temperature melt (850˚C) and slow cooling (2˚C/hour) of constituent elements. The single crystal X-ray diffraction pattern showed the 00l alignment and the high crystalline nature of the resultant sample. The rietveld fitted room temperature powder XRD revealed the phase purity and rhombohedral structure of the synthesized crystal. The formation and analysis of unit cell structure further verified the rhombohedral structure composed of three quintuple layers stacked one over the other. The SEM image showed the layered directional growth of the synthesized crystal carried out using the ZEISS-EVOMA-10 scanning electron microscope The electrical resistivity measurement was carried out using the conventional four-probe method on a quantum design Physical Property Measurement System (PPMS). The temperature dependent electrical resistivity plot for studied Sb2Te3 single crystal depicts metallic behaviour in the absence of any applied magnetic field. The synthesis as well as the structural characterization of as grown Sb2Te3 single crystal is reported and discussed in the present letter.

A facile chemical conversion synthesis of Sb2S3 nanotubes and the visible light-driven photocatalytic activities

PubMed Central

2012-01-01

We report a simple chemical conversion and cation exchange technique to realize the synthesis of Sb2S3 nanotubes at a low temperature of 90°C. The successful chemical conversion from ZnS nanotubes to Sb2S3 ones benefits from the large difference in solubility between ZnS and Sb2S3. The as-grown Sb2S3 nanotubes have been transformed from a weak crystallization to a polycrystalline structure via successive annealing. In addition to the detailed structural, morphological, and optical investigation of the yielded Sb2S3 nanotubes before and after annealing, we have shown high photocatalytic activities of Sb2S3 nanotubes for methyl orange degradation under visible light irradiation. This approach offers an effective control of the composition and structure of Sb2S3 nanomaterials, facilitates the production at a relatively low reaction temperature without the need of organics, templates, or crystal seeds, and can be extended to the synthesis of hollow structures with various compositions and shapes for unique properties. PMID:22448960

Zn3Sb4O6F6: Hydrothermal synthesis, crystal structure and nonlinear optical properties

NASA Astrophysics Data System (ADS)

Ali, Sk Imran; Zhang, Weiguo; Halasyamani, P. Shiv; Johnsson, Mats

2017-12-01

Zn3Sb4O6F6 has been synthesized hydrothermally at 230 °C. The crystal structure was determined from single crystal X-ray diffraction data. It crystallizes in the cubic non-centrosymmetric space group I-43m with the unit cell parameter a = 8.1291(4) Å and is isostructural with M3Sb4O6F6 (M = Co, Ni). The new compound is the first oxofluoride containing Zn2+ and a p-element cation with a stereochemically active lone pair. The crystal structure is made up by [ZnO2F4] octahedra forming a network via corner sharing at F-atoms and [SbO3] trigonal pyramids that form [Sb4O6] cages that connect via the O-atoms to the Zn-atoms. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation on Zn3Sb4O6F6 indicate an SHG intensity of approximately 40 × α-SiO2.

Competitive adsorption of As(III), As(V), Sb(III) and Sb(V) onto ferrihydrite in multi-component systems: Implications for mobility and distribution.

PubMed

Qi, Pengfei; Pichler, Thomas

2017-05-15

The simultaneous adsorption behavior and competitive interactions between As(III), As(V), Sb(III) and Sb(V) by ferrihydrite were evaluated in multi-component (binary, ternary, quaternary) systems. In binary systems, Sb(III) had a stronger inhibitory influence on As(III) adsorption than Sb(V) did, and As(V) had a stronger inhibitory effect on Sb(V) adsorption than As(III) did. In ternary systems, NO 3 - , PO 4 3- and SO 4 2- did not compete with the adsorption of As(III) and Sb(III). NO 3 - and SO 4 2- also had no distinct effect on the adsorption of As(V) and Sb(V), while PO 4 3- competed with As(V) and Sb(V) for surface sites. In quaternary systems, the simultaneous adsorption behavior of the four redox species was pH dependent. Sb(III) always showed the strongest adsorption affinity regardless of pH. At pH 3.5 As(III) showed the lowest affinity could be due to the presence and negative effect of Sb(III) and As(V). The Freundlich model provided a good fit for the simultaneous adsorption data under quaternary conditions. The study of competitive/simultaneous adsorption of the four possible redox species onto ferrihydrite contributed to a better understanding of their distribution, mobility and fate in the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Photoluminescence and structural properties of unintentional single and double InGaSb/GaSb quantum wells grown by MOVPE

NASA Astrophysics Data System (ADS)

Ahia, Chinedu Christian; Tile, Ngcali; Botha, Johannes R.; Olivier, E. J.

2018-04-01

The structural and photoluminescence (PL) characterization of InGaSb quantum well (QW) structures grown on GaSb substrate (100) using atmospheric pressure Metalorganic Vapor Phase Epitaxy (MOVPE) is presented. Both structures (single and double-InGaSb QWs) were inadvertently formed during an attempt to grow capped InSb/GaSb quantum dots (QDs). In this work, 10 K PL peak energies at 735 meV and 740 meV are suggested to be emissions from the single and double QWs, respectively. These lines exhibit red shifts, accompanied by a reduction in their full-widths at half-maximum (FWHM) as the excitation power decreases. The presence of a GaSb spacer in the double QW was found to increase the strength of the PL emission, which consequently gives rise to a reduced blue-shift and broadening of the PL emission line observed for the double QW with an increase in laser power, while the low thermal activation energy for the quenching of the PL from the double QW is attributed to the existence of threading dislocations, as seen in the bright field TEM image for this sample.

GaSb and Ga1-xInxSb Thermophotovoltaic Cells using Diffused Junction Technology in Bulk Substrates

NASA Astrophysics Data System (ADS)

Dutta, P. S.; Borrego, J. M.; Ehsani, H.; Rajagopalan, G.; Bhat, I. B.; Gutmann, R. J.; Nichols, G.; Baldasaro, P. F.

2003-01-01

This paper presents results of experimental and theoretical research on antimonide- based thermophotovoltaic (TPV) materials and cells. The topics discussed include: growth of large diameter ternary GaInSb bulk crystals, substrate preparation, diffused junction processes, cell fabrication and characterization, and, cell modeling. Ternary GaInSb boules up to 2 inches in diameter have been grown using the vertical Bridgman technique with a novel self solute feeding technique. A single step diffusion process followed by precise etching of the diffused layer has been developed to obtain a diffusion profile appropriate for high efficiency, p-n junction GaSb and GaInSb thermophotovoltaic cells. The optimum junction depth to obtain the highest quantum efficiency and open circuit voltage has been identified based on diffusion lengths (or minority carrier lifetimes), carrier mobility and experimental diffused impurity profiles. Theoretical assessment of the performance of ternary (GaInSb) and binary (GaSb) cells fabricated by Zn diffusion in bulk substrates has been performed using PC-1D one-dimensional computer simulations. Several factors affecting the cell performances such as the effects of emitter doping profile, emitter thickness and recombination mechanisms (Auger, radiative and Shockley-Read-Hall), the advantages of surface passivation and the impact of dark current due to the metallic grid will be discussed. The conditions needed for diffused junction cells on ternary and binary substrates to achieve similar performance to the epitaxially grown lattice- matched quaternary cells are identified.

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

The Quorum-Sensing Regulon of Vibriofischeri: Novel Components of the Autoinducer/LuxR Regulatory Circuit

DTIC Science & Technology

1999-06-01

cpdP, from the marine symbiotic bacterium Vibrio fische ri 160 Table of abbreviations 30C6-HSL AI-1 AI-2 C8-HSL CHAPS CNP EDTA FMN GFP HPLC ...using a Zorbax C18 1.0 mm by 150 mm reverse-phase column on a Hewlett-Packard 1090 HPLC /1040 diode array detector at the Harvard Microchemistry...separated by reversed-phase HPLC , and sequenced (Table 2; 10-PK12, 10-PK39, and 10-PK51). From two of the three peptide sequences (Materials and

Optimization of metamorphic buffers for MBE growth of high quality AlInSb/InSb quantum structures: Suppression of hillock formation

NASA Astrophysics Data System (ADS)

Shi, Y.; Gosselink, D.; Gharavi, K.; Baugh, J.; Wasilewski, Z. R.

2017-11-01

The optimization of metamorphic buffers for InSb/AlInSb QWs grown on GaAs (0 0 1) substrates is presented. With increasing surface offcut angle towards [ 1 1 bar 0 ] direction, the interaction of spiral growth around threading dislocations (TDs) with the offcut-induced atomic steps leads to a gradual change in the morphology of the AlSb buffer from one dominated by hillocks to that exhibiting near-parallel steps, and finally to a surface with increasing number of localized depressions. With the growth conditions used, the smoothest AlSb surface morphology was obtained for the offcut angles range of 0.8-1.3°. On substrates with 0° offcut, subsequent 3 repeats of Al0.24In0.76 Sb/Al0.12In0.88 Sb interlayers reduces the TD density of AlSb buffer by a factor of 10, while 70 times reduction in the surface density of TD-related hillocks is observed. The remaining hillocks have rectangular footprint and small facet angles with respect to GaAs (0 0 1) surface: 0.4° towards [ 1 1 bar 0 ] direction and 0.7° towards [1 1 0] direction. Their triangular-shaped sidewalls with regularly spaced atomic steps show occasional extra step insertion sites, characteristic of TD outcrops. Many of the observed sidewalls are dislocation free and offer atomically smooth areas of up to 1 μm2, already suitable for high-quality InSb growth and subsequent top-down fabrication of InSb nanowires. It is proposed that the sidewalls of the remaining hillocks offer local vicinal surfaces with atomic step density optimal for suppression of TD-induced spiral growth, thus providing the important information on the exact substrate offcut needed to achieve large hillock-free and atomically smooth areas on AlInSb metamorphic buffers.

Atmospheric Sb in the Arctic during the past 16,000 years: Responses to climate change and human impacts

NASA Astrophysics Data System (ADS)

Krachler, Michael; Zheng, Jiancheng; Fisher, David; Shotyk, William

2008-03-01

Applying strict clean room procedures and sector field inductively coupled plasma mass spectrometry (ICP-MS) methods, concentrations of Sb and Sc were determined in 57 sections of a 170.6-m-long ice core drilled on Devon Island, Arctic Canada, in 1999, providing a record of atmospheric Sb extending back 15,800 years. Natural background concentrations of Sb and Sc established during the period between 1300 years BP and 10,590 years BP averaged 0.08 ± 0.03 pg/g (N = 18) and 0.44 ± 0.20 pg/g (N = 17), respectively. Scandium, a conservative reference element, was used as a surrogate for mineral dust inputs. The Sb/Sc ratio of 0.13 ± 0.07 in these ancient ice samples is comparable to the corresponding ratio of 0.09 ± 0.03 in peat samples from Switzerland from circa 6000 to 9000 years BP, indicating that this natural background ratio might have a much broader validity. The natural background flux of Sb (0.7 ± 0.5 ng/m2/a) in the Arctic was approximately 500 times lower than that established in central Europe using peat cores. For comparison with background values, modern Sb fluxes calculated using 45 samples from a 5-m snow pit dug on Devon Island in 2004, reflecting 10 years of snow accumulation, yielded an average deposition rate of 340 ± 270 ng/m2/a (range: 20-1240 ng/m2/a) with pronounced accumulation of Sb during winter periods when air masses reaching the Arctic predominantly come from Eurasia. These data reveal that approximately 99.8% of the Sb deposited in the Arctic today originates from anthropogenic activities. Modern Sb enrichment factors averaged 25 (range: 8-121). The ice core provides evidence of Sb contamination dating from Phoenician/Greek, Roman, and medieval lead mining and smelting in Europe. Moreover, the ice core data indicate that anthropogenic sources of Sb have continuously dominated the atmospheric inputs to the Arctic for at least 700 years.

Features of high-temperature electroluminescence in an LED n-GaSb/n-InGaAsSb/p-AlGaAsSb heterostructure with high potential barriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danilov, L. V., E-mail: danleon84@mail.ru; Petukhov, A. A.; Mikhailova, M. P.

2016-06-15

The electroluminescent properties of a light-emitting diode n-GaSb/n-InGaAsSb/p-AlGaAsSb heterostructure with high potential barriers are studied in the temperature range of 290–470 K. An atypical temperature increase in the power of the long-wavelength luminescence band with an energy of 0.3 eV is experimentally observed. As the temperature increases to 470 K, the optical radiation power increases by a factor of 1.5–2. To explain the extraordinary temperature dependence of the radiation power, the recombination and carrier transport processes are theoretically analyzed in the heterostructure under study.

Potential for high thermoelectric performance in n-type Zintl compounds: A case study of Ba doped KAlSb 4

DOE PAGES

Ortiz, Brenden R.; Gorai, Prashun; Krishna, Lakshmi; ...

2017-01-11

High-throughput calculations (first-principles density functional theory and semi-empirical transport models) have the potential to guide the discovery of new thermoelectric materials. Herein we have computationally assessed the potential for thermoelectric performance of 145 complex Zintl pnictides. Of the 145 Zintl compounds assessed, 17% show promising n-type transport properties, compared with only 6% showing promising p-type transport. We predict that n-type Zintl compounds should exhibit high mobility μ n while maintaining the low thermal conductivity κ L typical of Zintl phases. Thus, not only do candidate n-type Zintls outnumber their p-type counterparts, but they may also exhibit improved thermoelectric performance. Frommore » the computational search, we have selected n-type KAlSb 4 as a promising thermoelectric material. Synthesis and characterization of polycrystalline KAlSb 4 reveals non-degenerate n-type transport. With Ba substitution, the carrier concentration is tuned between 10 18 and 10 19 e – cm –3 with a maximum Ba solubility of 0.7% on the K site. High temperature transport measurements confirm a high μ n (50 cm 2 V –1 s –1) coupled with a near minimum κ L (0.5 W m –1 K –1) at 370 °C. Together, these properties yield a zT of 0.7 at 370 °C for the composition K 0.99Ba 0.01AlSb 4. As a result, based on the theoretical predictions and subsequent experimental validation, we find significant motivation for the exploration of n-type thermoelectric performance in other Zintl pnictides.« less

Potential for high thermoelectric performance in n-type Zintl compounds: A case study of Ba doped KAlSb 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz, Brenden R.; Gorai, Prashun; Krishna, Lakshmi

High-throughput calculations (first-principles density functional theory and semi-empirical transport models) have the potential to guide the discovery of new thermoelectric materials. Herein we have computationally assessed the potential for thermoelectric performance of 145 complex Zintl pnictides. Of the 145 Zintl compounds assessed, 17% show promising n-type transport properties, compared with only 6% showing promising p-type transport. We predict that n-type Zintl compounds should exhibit high mobility μ n while maintaining the low thermal conductivity κ L typical of Zintl phases. Thus, not only do candidate n-type Zintls outnumber their p-type counterparts, but they may also exhibit improved thermoelectric performance. Frommore » the computational search, we have selected n-type KAlSb 4 as a promising thermoelectric material. Synthesis and characterization of polycrystalline KAlSb 4 reveals non-degenerate n-type transport. With Ba substitution, the carrier concentration is tuned between 10 18 and 10 19 e – cm –3 with a maximum Ba solubility of 0.7% on the K site. High temperature transport measurements confirm a high μ n (50 cm 2 V –1 s –1) coupled with a near minimum κ L (0.5 W m –1 K –1) at 370 °C. Together, these properties yield a zT of 0.7 at 370 °C for the composition K 0.99Ba 0.01AlSb 4. As a result, based on the theoretical predictions and subsequent experimental validation, we find significant motivation for the exploration of n-type thermoelectric performance in other Zintl pnictides.« less

Theoretical and experimental investigations of the properties of Ge2Sb2Te5 and indium-doped Ge2Sb2Te5 phase change material

NASA Astrophysics Data System (ADS)

Singh, Gurinder; Kaura, Aman; Mukul, Monika; Singh, Janpreet; Tripathi, S. K.

2014-06-01

We have carried out comprehensive computational and experimental study on the face-centered cubic Ge2Sb2Te5 (GST) and indium (In)-doped GST phase change materials. Structural calculations, total density of states and crystal orbital Hamilton population have been calculated using first-principle calculation. 5 at.% doping of In weakens the Ge-Te, Sb-Te and Te-Te bond lengths. In element substitutes Sb to form In-Te-like structure in the GST system. In-Te has a weaker bond strength compared with the Sb-Te bond. However, both GST and doped alloy remain in rock salt structure. It is more favorable to replace Sb with In than with any other atomic position. X-ray diffraction (XRD) analysis has been carried out on thin film of In-doped GST phase change materials. XRD graph reveals that In-doped phase change materials have rock salt structure with the formation of In2Te3 crystallites in the material. Temperature dependence of impedance spectra has been calculated for thin films of GST and doped material. Thickness of the as-deposited films is calculated from Swanepoel method. Absorption coefficient (α) has been calculated for amorphous and crystalline thin films of the alloys. The optical gap (indirect band gap) energy of the amorphous and crystalline thin films has also been calculated by the equation α hν = β (hν - E_{{g }} )2 . Optical contrast (C) of pure and doped phase change materials have also been calculated. Sufficient optical contrast has been found for pure and doped phase change materials.

Synthesis and characterization of Fe-Ti-Sb intermetallic compounds: Discovery of a new Slater-Pauling phase

NASA Astrophysics Data System (ADS)

Naghibolashrafi, N.; Keshavarz, S.; Hegde, Vinay I.; Gupta, A.; Butler, W. H.; Romero, J.; Munira, K.; LeClair, P.; Mazumdar, D.; Ma, J.; Ghosh, A. W.; Wolverton, C.

2016-03-01

Compounds of Fe, Ti, and Sb were prepared using arc melting and vacuum annealing. Fe2TiSb , expected to be a full Heusler compound crystallizing in the L 21 structure, was shown by XRD and SEM analyses to be composed of weakly magnetic grains of nominal composition Fe1.5TiSb with iron-rich precipitates in the grain boundaries. FeTiSb, a composition consistent with the formation of a half-Heusler compound, also decomposed into Fe1.5TiSb grains with Ti-Sb rich precipitates and was weakly magnetic. The dominant Fe1.5TiSb phase appears to crystallize in a defective L 21 -like structure with iron vacancies. Based on this finding, a first-principles DFT-based binary cluster expansion of Fe and vacancies on the Fe sublattice of the L 21 structure was performed. Using the cluster expansion, we computationally scanned >103 configurations and predict a novel, stable, nonmagnetic semiconductor phase to be the zero-temperature ground state. This new structure is an ordered arrangement of Fe and vacancies, belonging to the space group R 3 m , with composition Fe1.5TiSb , i.e., between the full- and half-Heusler compositions. This phase can be visualized as alternate layers of L 21 phase Fe2TiSb and C 1b phase FeTiSb, with layering along the [111] direction of the original cubic phases. Our experimental results on annealed samples support this predicted ground-state composition, but further work is required to confirm that the R 3 m structure is the ground state.

Nickel antimony oxide (NiSb2O6): A fascinating nanostructured material for gas sensing application

NASA Astrophysics Data System (ADS)

Singh, Archana; Singh, Ajendra; Singh, Satyendra; Tandon, Poonam

2016-02-01

Fabrication of nanocrystalline NiSb2O6 thin films via sol-gel spin coating method towards the development of liquefied petroleum gas (LPG) sensor operable at room temperature (25 °C) is being reported. Nanostructural, surface morphological and optical properties of trirutile-type NiSb2O6 have been investigated in order to explore the parameters of interest. The crystallite size has been found to be 19 nm. A detailed sensing performance (sensitivity, sensor response, response and recovery times, reproducibility and long term stability) of NiSb2O6 nanostructures grown on alumina substrate has been investigated.

Phase change properties of Ge2Sb2Te5 compared to Ge4Sb1Te5 with respect to data storage applications

NASA Astrophysics Data System (ADS)

Friedrich, I.; Weidenhof, V.; Njoroge, W.; Franz, P.; Wuttig, M.

2000-03-01

To be able to adjust material properties to the demands of rewritable optical storage applications (high data density and transfer rates) we have investigated and compared the phase change characteristics of thin sputtered Ge2Sb2Te5- and Ge4Sb1Te5-films. Both crystallize into a rocksalt structure at 157C, and 150C, respectively. The material with the higher content of Ge shows a significantly higher activation energy (EA=3.7eV in comparison to EA=2.24eV), as confirmed by temperature dependent electrical measurements. This results in a larger incubation time for laser modification on the ns-scale. Ge2Sb2Te5 shows a second transition into a rather complex hexagonal structure at 310C (EA=3.64eV). The optical properties of both phases are slightly different. Laser modified areas are always in the first phase as confirmed by TEM and SAD. Hence there is a risk of a coexistence of two phases which would lead to an increase of the noise level in storage applications. This can be avoided by using a crystalline matrix with rocksalt structure. By capping the single phase change films with a thin dielectric layer the transition temperatures and activation energies are increasing for both materials, which might be attributed to changes of the tension state at the interface. footnotes the note goes between the ; number. set of curly braces; then put the associated URL in the set. The command may go anywhere in the abstract. the text in the first curly braces will show the printed version.

Thermoelectric and mechanical properties of spark plasma sintered Cu3SbSe3 and Cu3SbSe4: Promising thermoelectric materials

NASA Astrophysics Data System (ADS)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

2014-12-01

We report the synthesis of thermoelectric compounds, Cu3SbSe3 and Cu3SbSe4, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu3SbSe4 exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu3SbSe3, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu3SbSe4 was found to be ˜1.2 as compared to 0.2 V-1 for Cu3SbSe3 at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Simulation and optimization performance of GaAs/GaAs0.5Sb0.5/GaSb mechanically stacked tandem solar cells

NASA Astrophysics Data System (ADS)

Tayubi, Y. R.; Suhandi, A.; Samsudin, A.; Arifin, P.; Supriyatman

2018-05-01

Different approaches have been made in order to reach higher solar cells efficiencies. Concepts for multilayer solar cells have been developed. This can be realised if multiple individual single junction solar cells with different suitably chosen band gaps are connected in series in multi-junction solar cells. In our work, we have simulated and optimized solar cells based on the system mechanically stacked using computer simulation and predict their maximum performance. The structures of solar cells are based on the single junction GaAs, GaAs0.5Sb0.5 and GaSb cells. We have simulated each cell individually and extracted their optimal parameters (layer thickness, carrier concentration, the recombination velocity, etc), also, we calculated the efficiency of each cells optimized by separation of the solar spectrum in bands where the cell is sensible for the absorption. The optimal values of conversion efficiency have obtained for the three individual solar cells and the GaAs/GaAs0.5Sb0.5/GaSb tandem solar cells, that are: η = 19,76% for GaAs solar cell, η = 8,42% for GaAs0,5Sb0,5 solar cell, η = 4, 84% for GaSb solar cell and η = 33,02% for GaAs/GaAs0.5Sb0.5/GaSb tandem solar cell.

On-line determination of Sb(III) and total Sb using baker's yeast immobilized on polyurethane foam and hydride generation inductively coupled plasma optical emission spectrometry

NASA Astrophysics Data System (ADS)

Menegário, Amauri A.; Silva, Ariovaldo José; Pozzi, Eloísa; Durrant, Steven F.; Abreu, Cassio H.

2006-09-01

The yeast Saccharomyces cerevisiae was immobilized in cubes of polyurethane foam and the ability of this immobilized material to separate Sb(III) and Sb(V) was investigated. A method based on sequential determination of total Sb (after on-line reduction of Sb(V) to Sb(III) with thiourea) and Sb(III) (after on-line solid-liquid phase extraction) by hydride generation inductively coupled plasma optical emission spectrometry is proposed. A flow system assembled with solenoid valves was used to manage all stages of the process. The effects of pH, sample loading and elution flow rates on solid-liquid phase extraction of Sb(III) were evaluated. Also, the parameters related to on-line pre-reduction (reaction coil and flow rates) were optimized. Detection limits of 0.8 and 0.15 μg L - 1 were obtained for total Sb and Sb(III), respectively. The proposed method was applied to the analysis of river water and effluent samples. The results obtained for the determination of total Sb were in agreement with expected values, including the river water Standard Reference Material 1640 certified by the National Institute of Standards and Technology (NIST). Recoveries of Sb(III) and Sb(V) in spiked samples were between 81 ± 19 and 111 ±15% when 120 s of sample loading were used.

As(V) and Sb(V) co-adsorption onto ferrihydrite: synergistic effect of Sb(V) on As(V) under competitive conditions.

PubMed

Wu, Debo; Sun, Sheng-Peng; He, Minghe; Wu, Zhangxiong; Xiao, Jie; Chen, Xiao Dong; Wu, Winston Duo

2018-05-01

Competitive adsorption of As(V) and Sb(V) at environmentally relevant concentrations onto ferrihydrite was investigated. Batch experiments and XPS analyses confirmed that in a binary system, the presence of Sb(V) exhibited a slight synergistic effect on As(V) adsorption. XPS analyses showed that As(V) and Sb(V) adsorption led to obvious diminishment of Fe-O-Fe and Fe-O-H bonds respectively. At pH of 9, a more significant decrease of Fe-O-Fe was observed in the binary system than that in a single system, indicating that As(V) displayed an even stronger interaction with lattice oxygen atoms under competitive conditions. Basically, ionic strength demonstrated a negligible or positive influence on As(V) and Sb(V) adsorption in binary system. Study of adsorption sequence also indicated that the presence of Sb(V) showed a promotion effect on As(V) adsorption at neutral pHs. Considering that co-contamination of As and Sb in waters has been of great concern throughout the world, our findings contributed to a better understanding of their distribution, mobility, and fate in environment.

Morphology, structure, optical, and electrical properties of AgSbO3

NASA Astrophysics Data System (ADS)

Yi, Z. G.; Liu, Y.; Withers, R. L.

2010-07-01

The morphology of defect pyrochlore-type, AgSbO3 microparticle/nanoparticles obtained via solid state reaction evolve from irregular to Fullerene-like polyhedra before finally decomposing into metal-organic framework-5 like particles with increase in sintering temperature. The defect pyrochlore-type AgSbO3 particles are slightly Ag deficient while the valence of the antimony ion is shown to be +5 giving rise to a probable stoichiometry of Ag1-xSbVO3-x/2, with x˜0.01-0.04. A highly structured diffuse intensity distribution observed via electron diffraction is interpreted in terms of correlated displacements of one-dimensional (1D) silver ion chains along ⟨110⟩ directions. A redshifting in the absorption edges in UV-visible absorption spectra is observed for samples prepared at sintering temperatures higher than 1000 °C and attributed to the surface plasma resonance effect associated with small amounts of excess metallic Ag on the Ag1-xSbVO3-x/2 particles. An electrical properties investigation of the silver antimonate samples via dielectric, conductivity, and electric modulus spectroscopy shows a prominent dielectric relaxation associated with grain boundaries. The silver ion conductivity is associated with correlated displacements of 1D silver ion chains along ⟨110⟩ directions.

The effects of electron and proton radiation on GaSb infrared solar cells

NASA Technical Reports Server (NTRS)

Gruenbaum, P. E.; Avery, J. E.; Fraas, L. M.

1991-01-01

Gallium antimonide (GaSb) infrared solar cells were exposed to 1 MeV electrons and protons up to fluences of 1 times 10(exp 15) cm (-2) and 1 times 10(exp 12) cm (-2) respectively. In between exposures, current voltage and spectral response curves were taken. The GaSb cells were found to degrade slightly less than typical GaAs cells under electron irradiation, and calculations from spectral response curves showed that the damage coefficient for the minority carrier diffusion length was 3.5 times 10(exp 8). The cells degraded faster than GaAs cells under proton irradiation. However, researchers expect the top cell and coverglass to protect the GaSb cell from most damaging protons. Some annealing of proton damage was observed at low temperatures (80 to 160 C).

Effect of antimony segregation on the electronic properties of InAs/InAsSb superlattices

NASA Astrophysics Data System (ADS)

Haugan, H. J.; Szmulowicz, F.; Hudgins, J. J.; Cordonnier, L. E.; Brown, G. J.

2017-08-01

There has been great progress in recent years in advancing the state-of-the-art of Ga-free InAs/InAsSb superlattice (SL) materials for infrared detector applications, spurred by the observation of long minority carrier lifetimes in this material system. However, compositional and dimensional changes through antimony (Sb) segregation alter the detector properties from those originally designed. For this reason, in this work, the authors explore epitaxial conditions that can mitigate this segregation in order to produce high-quality SL materials for optimum detector performance. A nominal SL structure of 7.7 nm InAs/3.5 nm InAs0.7 Sb0.3 tailored for an approximately six-micron response at 5 K was used to optimize the epitaxial parameters. Since the growth of mixed AsSb alloys is complicated by the potential reaction of As with Sb surfaces, the authors vary the substrate temperature (Ts) in order to control the As surface reaction on a Sb surface. Experimental results indicate that the SL sample grown at the lowest investigated Ts produces the highest Sb-mole fraction x of 0.3 in InAs1-x Sbx layers, which then decreases by 21 % as the Ts increases from 395 to 440 °C. This reduction causes an approximately 30 meV blueshift in the position of the excitonic photoluminescence (PL) peak. This finding differs from the results obtained from the Ga-containing InAs/GaSb SL equivalents, where the PL peak position remains constant at about 220 meV, regardless of Ts. The Ga-free SLs generally generate a broader PL linewidth than the corresponding Ga-containing SLs due to the higher spatial Sb distribution at the hetero-interfaces engendered by Sb segregation. In order for this newly proposed Ga-free SL materials to be viable for detector applications, the material problem associated with Sb segregation needs to be adequately controlled and further mitigated.

Sb-Te Phase-change Materials under Nanoscale Confinement

NASA Astrophysics Data System (ADS)

Ihalawela, Chandrasiri A.

Size, speed and efficiency are the major challenges of next generation nonvolatile memory (NVM), and phase-change memory (PCM) has captured a great attention due to its promising features. The key for PCM is rapid and reversible switching between amorphous and crystalline phases with optical or electrical excitation. The structural transition is associated with significant contrast in material properties which can be utilized in optical (CD, DVD, BD) and electronic (PCRAM) memory applications. Importantly, both the functionality and the success of PCM technology significantly depend on the core material and its properties. So investigating PC materials is crucial for the development of PCM technology to realized enhanced solutions. In regards to PC materials, Sb-Te binary plays a significant role as a basis to the well-known Ge-Sb-Te system. Unlike the conventional deposition methods (sputtering, evaporation), electrochemical deposition method is used due to its multiple advantages, such as conformality, via filling capability, etc. First, the controllable synthesis of Sb-Te thin films was studied for a wide range of compositions using this novel deposition method. Secondly, the solid electrolytic nature of stoichiometric Sb2Te3 was studied with respect to precious metals. With the understanding of 2D thin film synthesis, Sb-Te 1D nanowires (18 - 220 nm) were synthesized using templated electrodeposition, where nanoporous anodic aluminum oxide (AAO) was used as a template for the growth of nanowires. In order to gain the controllability over the deposition in high aspect ratio structures, growth mechanisms of both the thin films and nanowires were investigated. Systematic understanding gained thorough previous studies helped to formulate the ultimate goal of this dissertation. In this dissertation, the main objective is to understand the size effect of PC materials on their phase transition properties. The reduction of effective memory cell size in conjunction with

Preparation and Some Properties of N-Type IrxCo1-xSB3 Solid Solutions

NASA Technical Reports Server (NTRS)

Caillat, Thierry

1995-01-01

A number of studies have been recently devoted to the preparation and characterization of binary skutterudite materials to investigate their potential as advanced thermoelectric materials. These studies show that the potential of these binary skutterudite compounds is limited because of their relatively large thermal conductivity. In order to achieve high thermoelectric figure of merits for these materials, efforts should focus on thermal conductivity reduction. Recent results obtained on n-type CoSb3 and IrSb3 compounds have shown that n-type skutterudite materials might have a better potential for thermoelectric applications than p-type materials. The thermoelectric properties of p-type IrxCo1-xSb3 solid solutions have been recently investigated and it was shown that a substantial reduction in thermal conductivity was achieved. We prepared and measured some properties of n-type IrxCo1-xSb3 solid solutions. The samples are characterized by large Seebeck coefficient values and significantly lower thermal conductivity values than those measured on the binary compounds CoSb3 and IrSb3. A maximum ZT value of about 0.4 was obtained at a temperature of about 300(deg)C. Improvements in the figure of merit are possible in this system by optimization of the doping level.

Physics of bandgap formation in Cu-Sb-Se based novel thermoelectrics: the role of Sb valency and Cu d levels.

PubMed

Do, Dat; Ozolins, Vidvuds; Mahanti, S D; Lee, Mal-Soon; Zhang, Yongsheng; Wolverton, C

2012-10-17

In this paper we discuss the results of ab initio electronic structure calculations for Cu(3)SbSe(4) (Se4) and Cu(3)SbSe(3) (Se3), two narrow bandgap semiconductors of thermoelectric interest. We find that Sb is trivalent in both the compounds, in contrast to a simple nominal valence (ionic) picture which suggests that Sb should be 5 + in Se4. The gap formation in Se4 is quite subtle, with hybridization between Sb 5s and the neighboring Se 4s, 4p orbitals, position of Cu d states, and non-local exchange interaction, each playing significant roles. Thermopower calculations show that Se4 is a better p-type system. Our theoretical results for Se4 agree very well with recent experimental results obtained by Skoug et al (2011 Sci. Adv. Mater. 3 602).

Annealing studies of heteroepitaxial InSbN on GaAs grown by molecular beam epitaxy for long-wavelength infrared detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patra, Nimai C.; Bharatan, Sudhakar; Li Jia

2012-10-15

We report the effect of annealing on the structural, vibrational, electrical, and optical properties of heteropepitaxially grown InSbN epilayers on GaAs substrate by molecular beam epitaxy for long-wavelength infrared detector applications. As-grown epilayers exhibited high N incorporation in the both substitutional and interstitial sites, with N induced defects as evidenced from high resolution x-ray diffraction, secondary ion mass spectroscopy, and room temperature (RT) micro-Raman studies. The as-grown optical band gap was observed at 0.132 eV ({approx}9.4 {mu}m) and the epilayer exhibited high background carrier concentration at {approx}10{sup 18} cm{sup -3} range with corresponding mobility of {approx}10{sup 3} cm{sup 2}/Vs. Exmore » situ and in situ annealing at 430 Degree-Sign C though led to the loss of N but improved InSb quality due to effective annihilation of N related defects and other lattice defects attested to enhanced InSb LO phonon modes in the corresponding Raman spectra. Further, annealing resulted in the optical absorption edge red shifting to 0.12 eV ({approx}10.3 {mu}m) and the layers were characterized by reduced background carrier concentration in the {approx}10{sup 16} cm{sup -3} range with enhanced mobility in {approx}10{sup 4} cm{sup 2}/Vs range.« less

Strong far-infrared intersubband absorption under normal incidence in heavily n-type doped nonalloy GaSb-AlSb superlattices

NASA Technical Reports Server (NTRS)

Samoska, L. A.; Brar, Berinder; Kroemer, H.

1993-01-01

We report on long-wavelength intersubband absorption under normal incidence in heavily doped binary-binary GaSb-AlSb superlattices. Due to a small energy difference between the ellipsoidal L valleys in GaSb and the low-density-of-states Gamma minimum, electrons spill over from the first Gamma subband into the higher-energy L subband in GaSb wells, where they are allowed to make an intersubband transition under normally incident radiation. A peak fractional absorption per quantum well of 6.8 x 10 exp 3 (absorption coefficient alpha of about 8500/cm) is observed at about 15 microns wavelength for a sheet concentration of 1.6 x 10 exp 12 sq cm/well.

GaSb and GaSb/AlSb Superlattice Buffer Layers for High-Quality Photodiodes Grown on Commercial GaAs and Si Substrates

NASA Astrophysics Data System (ADS)

Gutiérrez, M.; Lloret, F.; Jurczak, P.; Wu, J.; Liu, H. Y.; Araújo, D.

2018-05-01

The objective of this work is the integration of InGaAs/GaSb/GaAs heterostructures, with high indium content, on GaAs and Si commercial wafers. The design of an interfacial misfit dislocation array, either on GaAs or Si substrates, allowed growth of strain-free devices. The growth of purposely designed superlattices with their active region free of extended defects on both GaAs and Si substrates is demonstrated. Transmission electron microscopy technique is used for the structural characterization and plastic relaxation study. In the first case, on GaAs substrates, the presence of dopants was demonstrated to reduce several times the threading dislocation density through a strain-hardening mechanism avoiding dislocation interactions, while in the second case, on Si substrates, similar reduction of dislocation interactions is obtained using an AlSb/GaSb superlattice. The latter is shown to redistribute spatially the interfacial misfit dislocation array to reduce dislocation interactions.

TEM study of the (SbS){sub 1+δ}(NbS{sub 2}){sub n}, (n=1, 2, 3; δ~1.14, 1.20) misfit layer phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez-Herrero, A., E-mail: adriangh@pdi.ucm.es; Landa-Cánovas, A.R.; Otero-Díaz, L.C.

In the Sb–Nb–S system four new misfit layer phases have been found and carefully investigated via Transmission Electron Microscopy (TEM). Their structures are of composite modulated structure type with stoichiometries that can be formulated as (SbS){sub 1+δ}(NbS{sub 2}){sub n}; for n=1, δ~1.14 and 1.19; for n=2, δ~1.18 and for n=3, δ~1.19. Selected Area Electron Diffraction (SAED) patterns show an almost commensurate fit between the pseudo-tetragonal (SbS) and the pseudo-orthohexagonal (NbS{sub 2}){sub n} subcells along the misfit direction a, with 3(SbS)≈5(NbS{sub 2}), being b the same for both sub-lattices and c the stacking direction. For n=1, a commensurate phase with 4a{submore » SbS}=7a{sub NbS2} has also been observed. In addition to the characteristic misfit and associated modulation of the two sub-structures, a second modulation is also present which appears to be primarily associated with the (SbS) sub-structure of both the n=1 and n=2 phases. High Resolution Transmission Electron Microscopy (HRTEM) images show ordered stacking sequences between the (SbS) and (NbS{sub 2}){sub n} lamellae for each of the four phases, however, disordered intergrowths were also occasionally found. Most of the crystals showed different kinds of twinning defects on quite a fine scale. Many crystals showed curled up edges. In some cases the lamellar crystals were entirely folded giving rise to similar diffraction patterns as found for cylindrical crystals. - Graphical abstract: Idealized structure models of the first three members of the homologous series (SbS){sub 1+δ}(NbS{sub 2}){sub n}. - Highlights: • Transmission Electron Microscopy study of misfit layer sulfides (SbS){sub 1+δ}(NbS{sub 2}){sub n}. • The structures consist of a (SbS) layer interleaved between n (NbS{sub 2}) layers. • Two different members n=1, one n=2 and one n=3 have been studied. • Twinning, intergrowths and different modulations in the (SbS) substructure.« less

Characteristics of Ge-Sb-Te films prepared by cyclic pulsed plasma-enhanced chemical vapor deposition.

PubMed

Suk, Kyung-Suk; Jung, Ha-Na; Woo, Hee-Gweon; Park, Don-Hee; Kim, Do-Heyoung

2010-05-01

Ge-Sb-Te (GST) thin films were deposited on TiN, SiO2, and Si substrates by cyclic-pulsed plasma-enhanced chemical vapor deposition (PECVD) using Ge{N(CH3)(C2H5)}, Sb(C3H7)3, Te(C3H7)3 as precursors in a vertical flow reactor. Plasma activated H2 was used as the reducing agent. The growth behavior was strongly dependent on the type of substrate. GST grew as a continuous film on TiN regardless of the substrate temperature. However, GST formed only small crystalline aggregates on Si and SiO2 substrates, not a continuous film, at substrate temperatures > or = 200 degrees C. The effects of the deposition temperature on the surface morphology, roughness, resistivity, crystallinity, and composition of the GST films were examined.

Molecular beam epitaxial growth and characterization of InSb1 - xNx on GaAs for long wavelength infrared applications

NASA Astrophysics Data System (ADS)

Patra, Nimai C.; Bharatan, Sudhakar; Li, Jia; Tilton, Michael; Iyer, Shanthi

2012-04-01

Recent research progress and findings in InSbN have attracted great attention due to its use in long wavelength infrared applications. A large bandgap reduction in InSb resulting from high N incorporation with minimal crystal defects is challenging due to relatively small atomic size of N. Hence optimization of growth conditions plays an important role in the growth of high-quality InSbN epilayers for device purposes. In this paper, we report on the correlation of structural, vibrational, electrical, and optical properties of molecular beam epitaxially grown InSbN epilayers grown on GaAs substrates, as a function of varying growth temperatures. Two dimensional growths of InSb and InSbN were confirmed from dynamic reflection high energy electron diffraction patterns and growth parameters were optimized. High crystalline quality of the epilayers is attested to by a low full width at half maximum of 200 arcsec from high resolution x-ray diffraction (HRXRD) scans and by the high intensity and well-resolved InSb longitudinal optical (LO) and 2nd order InSb LO mode observed from micro-Raman spectroscopy. The N incorporation in these InSbN epilayers is estimated to be 1.4% based on HRXRD simulation. X-ray photoelectron spectroscopy (XPS) studies reveal that most of the N present in the layers are in the form of In-N bonding. Variation of the lattice disorder with growth temperature is correlated with the types of N bonding present, the carrier concentration and mobility, observed in the corresponding XPS spectra and Hall measurements, respectively. XPS analysis, HRXRD scans, and Raman spectral analysis indicate that lower growth temperature favors In-N bonding which dictates N incorporation in the substitutional sites and lattice disorder, whereas, high growth temperature promotes the formation of In-N-Sb bonding. The best room temperature and 77 K electrical transport parameters and maximum redshift in the absorption edge have been achieved in the InSbN epilayer grown in

75 FR 69870 - Delegation of Authority Under 18 U.S.C. 249

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

... Authority Under 18 U.S.C. 249 AGENCY: Department of Justice. ACTION: Final rule. SUMMARY: This rule amends 28 CFR part 0 to delegate the Attorney General's certification authority under 18 U.S.C. 249..., the Shepard-Byrd Act created a new federal hate crime statute to be codified at 18 U.S.C. 249. The...

Heterointerface study of InAs/GaSb nanoridge heterostructures grown by metal organic chemical vapor deposition on V-grooved Si (0 0 1) substrates

NASA Astrophysics Data System (ADS)

Lai, Billy; Li, Qiang; Lau, Kei May

2018-02-01

InAs/GaSb nanoridge heterostructures were grown on V-grooved (0 0 1) Si by metal organic chemical vapor deposition. Combining the aspect ratio trapping process and a low temperature GaAs buffer, we demonstrated high quality GaSb nanoridge templates for InAs/GaSb heterostructure growth. Two different interfaces, a transitional GaAsSb and an InSb-like interface, were investigated when growing these heterostructures. A 500 °C growth temperature in conjunction with a GaAsSb interface was determined to produce the optimal interface, properly compensating for the tensile strain accumulated when growing InAs on GaSb. Without the need for a complicated switching sequence, this GaAsSb-like interface utilized at the optimized temperature is the initial step towards InAs/GaSb type II superlattice and other device structures integrated onto Si.

Thermodynamical properties of La-Ni-T (T = Mg, Bi and Sb) hydrogen storage systems

NASA Astrophysics Data System (ADS)

Giza, K.; Iwasieczko, W.; Pavlyuk, V. V.; Bala, H.; Drulis, H.

The hydrogen absorption properties of LaNi 4.8T 0.2 (T = Mg, Bi and Sb) alloys are reported. The effects of the substitution of Ni in the LaNi 5 compound with Mg, Bi and Sb are investigated. The ability of alloys to absorb hydrogen is characterized by the pressure-composition (p- c) isotherms. The p- c isotherms allow the determining thermodynamic parameters enthalpy (Δ H des) and entropy (Δ S des) of the dehydrogenation processes. The calculated Δ H des and Δ S des data helps to explain the decrease of hydrogen equilibrium pressure in alloys doped with Al, Mg and Bi and its increase in the Sb-doped LaNi 5 compound. Generally, partial substitution of Ni in LaNi 5 compound with Mg, Bi and Sb cause insignificant changes of hydrogen storage capacity compared to the hydrogen content in the initial LaNi 5H 6 hydride phase. However, it is worth to stress that, in the case of LaNi 4.8Bi 0.2, a small increase of H/f.u. up to 6.8 is observed. The obtained results in these investigations indicate that the LaNi 4.8T 0.2 (T = Al, Mg and Bi) alloys can be very attractive materials dedicated for negative electrodes in Ni/MH batteries.

Critical thickness of MBE-grown Ga 1-xIn xSb ( x<0.2) on GaSb

NASA Astrophysics Data System (ADS)

Nilsen, T. A.; Breivik, M.; Selvig, E.; Fimland, B. O.

2009-03-01

Several Ga 1-xIn xSb layers, capped with 1 μm of GaSb, were grown on GaSb(0 0 1) substrates by molecular beam epitaxy in a Varian Gen II Modular system using either the conventional sample growth position with substrate rotation, or a tilted sample position with no substrate rotation. The GaInSb layers were examined by X-ray diffraction (XRD) using both symmetrical and asymmetrical reflections. The "tilted sample method" gave a variation of ±25% in thickness of the Ga 1-xIn xSb layers, while the indium (In) content varied by ±10% around the nominal value. The disappearance of thickness fringes in 004 XRD scans was used to determine the onset of relaxation, as determining the in-plane lattice constant for tilted samples was found to be difficult. Determining residual strain in samples grown by the tilted method was likewise found to be very difficult. The critical thickness for several In mole fractions between 5% and 19% was determined and was found to be from 2.2 to 2.7 times higher than predicted by Matthews and Blakeslee (1974) [J. Crystal Growth 27 (1974) 118] but lower than that predicted by People and Bean (1985) [Appl. Phys. Lett. 47 (1985) 322].

Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water.

PubMed

Zou, Jian-Ping; Liu, Hui-Long; Luo, Jinming; Xing, Qiu-Ju; Du, Hong-Mei; Jiang, Xun-Heng; Luo, Xu-Biao; Luo, Sheng-Lian; Suib, Steven L

2016-07-20

Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment.

Electrical properties of n-type GaSb substrates and p-type GaSb buffer layers for InAs/InGaSb superlattice infrared detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchel, W. C., E-mail: William.Mitchel.1@us.af.mil; Haugan, H. J.; Mou, Shin

2015-09-15

Lightly doped n-type GaSb substrates with p-type GaSb buffer layers are the preferred templates for growth of InAs/InGaSb superlattices used in infrared detector applications because of relatively high infrared transmission and a close lattice match to the superlattices. We report here temperature dependent resistivity and Hall effect measurements of bare substrates and substrate-p-type buffer layer structures grown by molecular beam epitaxy. Multicarrier analysis of the resistivity and Hall coefficient data demonstrate that high temperature transport in the substrates is due to conduction in both the high mobility zone center Γ band and the low mobility off-center L band. High overallmore » mobility values indicate the absence of close compensation and that improved infrared and transport properties were achieved by a reduction in intrinsic acceptor concentration. Standard transport measurements of the undoped buffer layers show p-type conduction up to 300 K indicating electrical isolation of the buffer layer from the lightly n-type GaSb substrate. However, the highest temperature data indicate the early stages of the expected p to n type conversion which leads to apparent anomalously high carrier concentrations and lower than expected mobilities. Data at 77 K indicate very high quality buffer layers.« less

Magnetic and transport properties of Ce 6MnSb 15

NASA Astrophysics Data System (ADS)

Godart, Claude; Rogl, Peter; Alleno, Eric; Gonçalves, António P.; Rouleau, Olivier

2006-05-01

In our effort to look for new Ce/Yb-based compounds with large unit cell, we studied Ce 6MnSb 15. Rietveld refinements of X-ray powder diffraction confirm that the material crystallizes in orthorhombic structure La 6MnSb 15-type, Imm2 space group, with 2 Ce sites (8e and 4d) and lattice parameters a=15.1643 Å, b=19.3875 Å and c=4.2794 Å, which closely agree with those already published. Magnetic susceptibility results show a paramagnetic behavior and no magnetic order down to 2 K in contrast to antiferromagnetic order previously reported at 7 K. Resistivity shows a metallic behavior and the Seebeck coefficient is very low, typically -2 μV/K.

Measurement of InAsSb bandgap energy and InAs/InAsSb band edge positions using spectroscopic ellipsometry and photoluminescence spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webster, P. T.; Riordan, N. A.; Liu, S.

2015-12-28

The structural and optical properties of lattice-matched InAs{sub 0.911}Sb{sub 0.089} bulk layers and strain-balanced InAs/InAs{sub 1−x}Sb{sub x} (x ∼ 0.1–0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure ismore » used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and −380 and −367 meV for the valence band.« less

Improvement of the GaSb/Al2O3 interface using a thin InAs surface layer

NASA Astrophysics Data System (ADS)

Greene, Andrew; Madisetti, Shailesh; Nagaiah, Padmaja; Yakimov, Michael; Tokranov, Vadim; Moore, Richard; Oktyabrsky, Serge

2012-12-01

The highly reactive GaSb surface was passivated with a thin InAs layer to limit interface trap state density (Dit) at the III-V/high-k oxide interface. This InAs surface was subjected to various cleaning processes to effectively reduce native oxides before atomic layer deposition (ALD). Ammonium sulfide pre-cleaning and trimethylaluminum/water ALD were used in conjunction to provide a clean interface and annealing in forming gas (FG) at 350 °C resulted in an optimized fabrication for n-GaSb/InAs/high-k gate stacks. Interface trap density, Dit ≈ 2-3 × 1012 cm-2eV-1 resided near the n-GaSb conductance band which was extracted and compared with three different methods. Conductance-voltage-frequency plots showed efficient Fermi level movement and a sub-threshold slope of 200 mV/dec. A composite high-k oxide process was also developed using ALD of Al2O3 and HfO2 resulting in a Dit ≈ 6-7 × 1012 cm-2eV-1. Subjecting these samples to a higher (450 °C) processing temperature results in increased oxidation and a thermally unstable interface. p-GaSb displayed very fast minority carrier generation/recombination likely due to a high density of bulk traps in GaSb.

Mixed C18 and C1 modification on an optical fiber for chromatographic sensing.

PubMed

Zhou, Leiji; Wang, Kemin; Zuo, Xinbing; Choi, Martin M F; Chen, Yunqing; Huang, Shasheng

2003-09-01

An optical fiber-chromatographic sensor, aiming at simultaneous and selective response to multiple components following a chromatographic separation, is described. We report an improved approach for immobilization of octadecyl (C(18)) and methyl (C(1)) moieties as stationary phase on an optical fiber suitable as a sensing phase for organic solutes. By this approach, the stability and lifetime of the sensing layer as well as the detectability and retention behavior of the chromatographic sensor could be improved. Infrared spectroscopy was employed to confirm the presence of C(18) and C(1) moieties on the modified surface of the optical fiber. The chromatographic sensor was applied, with good sensitivity and chemical selectivity, to the simultaneous separation and detection of bromobenzene and toluene, using water as the mobile phase.

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

NASA Astrophysics Data System (ADS)

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.

Conduction- and Valence-Band Energies in Bulk InAs(1-x)Sb(x) and Type II InAs(1-x) Sb(x)/InAs Strained-Layer Superlattices

DTIC Science & Technology

2013-03-08

tions in the studied SLS structures . The fit of the dependence of the valence- band energy of unstrained InAs1!xSbx on the composition x with a... band . STRUCTURES Bulk InAsSb epilayers on metamorphic buffers and InAsSb/InAs strained-layer superlattices (SLS) were grown on GaSb substrates by solid...meV in InAs and Ev = 0 meV in InSb. For InAsSb with 22.5% Sb grown on GaSb , an unstrained valence- band energy of Ev = !457 meV was obtained. For the

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2014 CFR

2014-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2012 CFR

2012-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2013 CFR

2013-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

Sb-rich Si-Sb-Te phase change material for multilevel data storage: The degree of disorder in the crystalline state

NASA Astrophysics Data System (ADS)

Zhou, Xilin; Wu, Liangcai; Song, Zhitang; Rao, Feng; Cheng, Yan; Peng, Cheng; Yao, Dongning; Song, Sannian; Liu, Bo; Feng, Songlin; Chen, Bomy

2011-07-01

The phase change memory with monolayer chalcogenide film (Si18Sb52Te30) is investigated for the feasibility of multilevel data storage. During the annealing of the film, a relatively stable intermediate resistance can be obtained at an appropriate heating rate. The transmission electron microscopy in situ analysis reveals a conversion of crystallization mechanism from nucleation to crystal growth, which leads a continuous reduction in the degree of disorder. It is indicated from the electrical properties of the devices that the fall edge of the voltage pulse is the critical factor that determines a reliable triple-level resistance state of the phase change memory cell.

Simultaneous quantification of paracetamol, acetylsalicylic acid and papaverine with a validated HPLC method.

PubMed

Kalmár, Eva; Gyuricza, Anett; Kunos-Tóth, Erika; Szakonyi, Gerda; Dombi, György

2014-01-01

Combined drug products have the advantages of better patient compliance and possible synergic effects. The simultaneous application of several active ingredients at a time is therefore frequently chosen. However, the quantitative analysis of such medicines can be challenging. The aim of this study is to provide a validated method for the investigation of a multidose packed oral powder that contained acetylsalicylic acid, paracetamol and papaverine-HCl. Reversed-phase high-pressure liquid chromatography was used. The Agilent Zorbax SB-C18 column was found to be the most suitable of the three different stationary phases tested for the separation of the components of this sample. The key parameters in the method development (apart from the nature of the column) were the pH of the aqueous phase (set to 3.4) and the ratio of the organic (acetonitrile) and the aqueous (25 mM phosphate buffer) phases, which was varied from 7:93 (v/v) to 25:75 (v/v) in a linear gradient, preceded by an initial hold. The method was validated: linearity, precision (repeatability and intermediate precision), accuracy, specificity and robustness were all tested, and the results met the ICH guidelines. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Characterization and identification of iridoid glucosides, flavonoids and anthraquinones in Hedyotis diffusa by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

PubMed

Liu, E-Hu; Zhou, Ting; Li, Guo-Bin; Li, Jing; Huang, Xiu-Ning; Pan, Feng; Gao, Ning

2012-01-01

The multiple bioactive constituents in Hedyotis diffusa Willd. (H. diffusa) were extracted and characterized by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS(n)). The optimized separation condition was obtained using an Agilent ZorBax SB-C18 column (4.6×150 mm, 5 μm) and gradient elution with water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid), under which baseline separation for the majority of compounds was achieved. Among the compounds detected, 14 iridoid glucosides, 10 flavonoids, 7 anthraquinones, 1 coumarin and 1 triterpene were unambiguously identified or tentatively characterized based on their retention times and mass spectra in comparison with the data from standards or references. The fragmentation behavior for different types of constituents was also investigated, which could contribute to the elucidation of these constituents in H. diffusa. The present study reveals that even more iridoid glycosides were found in H. diffusa than hitherto assumed. The occurrence of two iridoid glucosides and five flavonoids in particular has not yet been described. This paper marks the first report on the structural characterization of chemical compounds in H. diffusa by a developed HPLC-ESI-MS(n) method. Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of 25 active constituents in the total flavonoids extract from Herba Desmodii Styracifolii by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Guo, Panpan; Yan, Wenying; Han, Qingjie; Wang, Chunying; Zhang, Zijian

2015-04-01

A sensitive and selective high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous determination of 25 active constituents, including 21 flavonoids and four phenolic acids in the total flavonoids extract from Herba Desmodii Styracifolii for the first time. Among the 25 compounds, seven compounds including caffeic acid, acacetin, genistein, genistin, diosmetin, diosmin and hesperidin were identified and quantified for the first time in Herba Desmodii Styracifolii. Chromatographic separation was accomplished on a ZORBAX SB-C18 (250 mm×4.6 mm, 5.0 μm) column using gradient elution of methanol and 0.1‰ acetic acid v/v at a flow rate of 1.0 mL/min. The identification and quantification of the analytes were achieved using negative electrospray ionization mass spectrometry in multiple-reaction monitoring mode. The method was fully validated in terms of limits of detection and quantification, linearity, precision and accuracy. The results indicated that the developed method is simple, rapid, specific and reliable. Furthermore, the developed method was successfully applied to quantify the 25 active components in six batches of total flavonoids extract from Herba Desmodii Styracifolii. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A validated high-performance liquid chromatography method with diode array detection for simultaneous determination of nine flavonoids in Senecio cannabifolius Less.

PubMed

Niu, Tian-Zeng; Zhang, Yu-Wei; Bao, Yong-Li; Wu, Yin; Yu, Chun-Lei; Sun, Lu-Guo; Yi, Jing-Wen; Huang, Yan-Xin; Li, Yu-Xin

2013-03-25

A reversed phase high performance liquid chromatography method coupled with a diode array detector (HPLC-DAD) was developed for the first time for the simultaneous determination of 9 flavonoids in Senecio cannabifolius, a traditional Chinese medicinal herb. Agilent Zorbax SB-C18 column was used at room temperature and the mobile phase was a mixture of acetonitrile and 0.5% formic acid (v/v) in water in the gradient elution mode at a flow-rate of 1.0mlmin(-1), detected at 360nm. Validation of this method was performed to verify the linearity, precision, limits of detection and quantification, intra- and inter-day variabilities, reproducibility and recovery. The calibration curves showed good linearities (R(2)>0.9995) within the test ranges. The relative standard deviation (RSD) of the method was less than 3.0% for intra- and inter-day assays. The samples were stable for at least 96h, and the average recoveries were between 90.6% and 102.5%. High sensitivity was demonstrated with detection limits of 0.028-0.085μg/ml for flavonoids. The newly established HPLC method represents a powerful technique for the quality assurance of S. cannabifolius. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous quantification of major flavonoids in "Bawanghua", the edible flower of Hylocereus undatus using pressurised liquid extraction and high performance liquid chromatography.

PubMed

Yi, Yan; Zhang, Qing-Wen; Li, Song-Lin; Wang, Ying; Ye, Wen-Cai; Zhao, Jing; Wang, Yi-Tao

2012-11-15

A pressurised liquid extraction (PLE) and high performance liquid chromatography (HPLC) method was developed for simultaneous quantification of six major flavonoids in edible flower of Hylocereus undatus. In order to achieve the baseline separation of two pairs of isomers, the HPLC conditions were optimised with different kind of reversed phase columns and mobile phase gradient programs. In addition, the solvent concentration, extraction temperature, extraction time and flush cycle for PLE were also optimised. Zorbax SB-C8 (100×2.1 mm, 1.8 μm) column was chosen with acetonitrile and water containing 0.1% trifluoroacetic acid as mobile phase, the six analytes were eluted with baseline separation. The calibration curves showed good linearity (r(2)>0.9994) with LODs and LOQs less than 0.90 and 3.60 ng respectively. The RSDs for intra- and inter-day repeatability was not more than 1.09% and 1.79% respectively. The overall recovery of the assay was 96.9-105.2%. The sample was stable for at least 12 h. The newly established method was successfully applied to quantify six flavonoids in different parts of "Bawanghua", and the commercial samples from different locations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simultaneous determination of naringenin and hesperetin in rats after oral administration of Da-Cheng-Qi decoction by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Liu, Ying; Xu, Fengguo; Zhang, Zunjian; Song, Rui; Tian, Yuan

2008-07-01

To quantify naringenin and hesperetin in rat plasma after oral administration of Da-Cheng-Qi decoction, a famous purgative traditional Chinese medicine, a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated. The HPLC separation was carried out on a Zorbax SB-C(18) column using 0.1% formic acid-methanol as mobile phase and estazolam as internal standard after the sample of rat plasma had been cleaned up with one-step protein precipitation using methanol. Atmospheric pressure chemical ionization in the positive ion mode and selected reaction monitoring method was developed to determine the active components. This method was validated in terms of recovery, linearity, accuracy and precision (intra- and inter-batch variation). The recoveries of naringenin and hesperetin were 72.8-76.6 and 75.7-77.2%, respectively. Linearity in rat plasma was observed over the range of 0.5-250 ng/mL (r2 > 0.99) for both naringenin and hesperetin. The accuracy and precision were well within the acceptable range and the relative standard deviation of the measured rat plasma samples was less than 15% (n = 5). The validated method was successfully applied for the evaluation of the pharmacokinetics of naringenin and hesperetin administered to six rats.

Development and validation of a sensitive LC-MS-MS method for the simultaneous determination of multicomponent contents in artificial Calculus Bovis.

PubMed

Peng, Can; Tian, Jixin; Lv, Mengying; Huang, Yin; Tian, Yuan; Zhang, Zunjian

2014-02-01

Artificial Calculus Bovis is a major substitute in clinical treatment for Niuhuang, a widely used, efficacious but rare traditional Chinese medicine. However, its chemical structures and the physicochemical properties of its components are complicated, which causes difficulty in establishing a set of effective and comprehensive methods for its identification and quality control. In this study, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry method was successfully developed and validated for the simultaneous determination of bilirubin, taurine and major bile acids (including six unconjugated bile acids, two glycine-conjugated bile acids and three taurine-conjugated bile acids) in artificial Calculus Bovis using a Zorbax SB-C18 column with a gradient elution of methanol and 10 mmol/L ammonium acetate in aqueous solution (adjusted to pH 3.0 with formic acid). The mass spectra were obtained in the negative ion mode using dehydrocholic acid as the internal standard. The content of each analyte in artificial Calculus Bovis was determined by monitoring specific ion pairs in the selected reaction monitoring mode. All analytes demonstrated perfect linearity (r(2) > 0.994) in a wide dynamic range, and 10 batches of samples from different sources were further analyzed. This study provided a comprehensive method for the quality control of artificial Calculus Bovis.

Quantification of lipoic acid in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Chen, Jun; Jiang, Wenming; Cai, Jia; Tao, Weixing; Gao, Xiaoling; Jiang, Xinguo

2005-09-25

A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of lipoic acid (LA) in human plasma. LA and the internal standard, naproxen, were extracted from a 500 microl plasma sample by one-step deproteination using acetonitrile. Chromatographic separation was performed on a Zorbax SB-C(18) Column (100 mmx3.0mm i.d. with 3.5 microm particle size) with the mobile phase consisting of acetonitrile and 0.1% acetic acid (pH 4, adjusted with ammonia solution) (65:35, v/v), and the flow rate was set at 0.3 ml/min. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was linear over the concentration range of 5-10,000 ng/ml for LA. The intra- and inter-day precisions were less than 7% and accuracy ranged from -7.87 to 9.74% at the LA concentrations tested. The present method provides a relatively simple and sensitive assay with short turn-around time. The method has been successfully applied to a clinical pharmacokinetic study of LA in 10 healthy subjects.

Speciation Analysis of Trace Mercury in Sea Cucumber Species of Apostichopus japonicus Using High-Performance Liquid Chromatography Conjunction With Inductively Coupled Plasma Mass Spectrometry.

PubMed

Liu, Hao; Luo, Jiaoyang; Ding, Tong; Gu, Shanyong; Yang, Shihai; Yang, Meihua

2018-03-25

In this paper, a simple and cost-effective method using high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry with a rapid ultrasound-assisted extraction was used for analysis speciation of trace mercury in sea cucumber species of Apostichopus japonicus. The effective separation of inorganic mercury, methylmercury, and ethylmercury was achieved within 10 min using Agilent ZORBAX SB-C 18 analytical and guard columns with an isocratic mobile phase consisting of 8% methanol and 92% H 2 O containing 0.12% L-cysteine (m/v) and 0.01 mol/L ammonium acetate. Mercury species were extracted from A. japonicus samples using a solution containing 2-mercaptoethanol, L-cysteine, and hydrochloric acid and sonicating for 0.5 h. The limits of detection of inorganic mercury, methylmercury, and ethylmercury were 0.12, 0.08, and 0.20 μg/L, and the minimum detectable concentrations (measured at 0.500 g sample volume in 10.00 mL) were 2.4, 1.6, and 4.0 μg/kg, respectively. Analysis of a scallop certified reference material (GBW 10024) revealed accordance between the experimental and certified values. This study provides a reference for the evaluation of mercury speciation in sea cucumber and other seafood.

Synchrotron x-ray study of a low roughness and high efficiency K 2 CsSb photocathode during film growth

DOE PAGES

Xie, Junqi; Demarteau, Marcel; Wagner, Robert; ...

2017-04-24

Reduction of roughness to the nm level is critical of achieving the ultimate performance from photocathodes used in high gradient fields. The thrust of this paper is to explore the evolution of roughness during sequential growth, and to show that deposition of multilayer structures consisting of very thin reacted layers results in an nm level smooth photocathode. Synchrotron x-ray methods were applied to study the multi-step growth process of a high efficiency K 2CsSb photocathode. We observed a transition point of the Sb film grown on Si at the film thickness of similar to 40 angstrom with the substrate temperaturemore » at 100 degrees C and the growth rate at 0.1 Å s -1. The final K 2CsSb photocathode exhibits a thickness of around five times that of the total deposited Sb film regardless of how the Sb film was grown. The film surface roughening process occurs first at the step when K diffuses into the crystalline Sb. Furthermore, the photocathode we obtained from the multi-step growth exhibits roughness in an order of magnitude lower than the normal sequential process. X-ray diffraction measurements show that the material goes through two structural changes of the crystalline phase during formation, from crystalline Sb to K 3Sb and finally to K 2CsSb.« less

Synchrotron x-ray study of a low roughness and high efficiency K 2 CsSb photocathode during film growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Junqi; Demarteau, Marcel; Wagner, Robert

Reduction of roughness to the nm level is critical of achieving the ultimate performance from photocathodes used in high gradient fields. The thrust of this paper is to explore the evolution of roughness during sequential growth, and to show that deposition of multilayer structures consisting of very thin reacted layers results in an nm level smooth photocathode. Synchrotron x-ray methods were applied to study the multi-step growth process of a high efficiency K 2CsSb photocathode. We observed a transition point of the Sb film grown on Si at the film thickness of similar to 40 angstrom with the substrate temperaturemore » at 100 degrees C and the growth rate at 0.1 Å s -1. The final K 2CsSb photocathode exhibits a thickness of around five times that of the total deposited Sb film regardless of how the Sb film was grown. The film surface roughening process occurs first at the step when K diffuses into the crystalline Sb. Furthermore, the photocathode we obtained from the multi-step growth exhibits roughness in an order of magnitude lower than the normal sequential process. X-ray diffraction measurements show that the material goes through two structural changes of the crystalline phase during formation, from crystalline Sb to K 3Sb and finally to K 2CsSb.« less

Development of an ion-pair HPLC method for investigation of energy charge changes in cerebral ischemia of mice and hypoxia of Neuro-2a cell line.

PubMed

Chen, Yunyun; Xing, Dongming; Wang, Wei; Ding, Yi; Du, Lijun

2007-06-01

The determination of adenine nucleotides and energy charge (EC) has great importance in the characterization of cerebral ischemic injury and post-ischemic recovery. An IP-HPLC method was developed for the quantification of AMP, ADP, ATP and EC in cerebral ischemia and hypoxia of the Neuro-2a cell line. The chromatographic conditions were: a Zorbax SB-C18 reversed-phase column; mobile phase 100 mM KH(2)PO(4), 1 mM tetrabutylammonium hydroxide, and 2.5% acetonitrile, brought to pH 7.0 with potassium hydroxide (4 M), filtered through a 0.45 microm Millipore filter and degassed prior to use. The flow-rate was 1.0 mL/min. The injection volume was 20 microL. Detection was performed at a wavelength of 254 nm under a constant temperature (27 +/- 1 degrees C). The method was validated by means of linearity, using calibration curves constructed with five concentration levels of each compound. The limit of detection was also determined. The system precision was calculated as the coefficient of variation for five injections for each compound tested. Cerebral tissue was homogenized (4 degrees C) in 1 mL of an ice-cold 6% trichloroacetic acid that contained ATPase inhibitor and obtained good recovery (>90%). The results show that the described method for the determination of adenine nucleotides by HPLC has good linearity, limit of detection, precision and specificity, and is simple and rapid to perform. Copyright 2007 John Wiley & Sons, Ltd.

High-Temperature Characteristics of an InAsSb/AlAsSb n+Bn Detector

NASA Astrophysics Data System (ADS)

Ting, David Z.; Soibel, Alexander; Höglund, Linda; Hill, Cory J.; Keo, Sam A.; Fisher, Anita; Gunapala, Sarath D.

2016-09-01

The high-temperature characteristics of a mid-wavelength infrared (MWIR) detector based on the Maimon-Wicks InAsSb/AlAsSb nBn architecture was analyzed. The dark current characteristics are examined in reference to recent minority carrier lifetime results. The difference between the responsivity and absorption quantum efficiency (QE) at shorter wavelengths is clarified in terms of preferential absorption of higher-energy photons in the top contact layer, which cannot provide reverse-bias photo-response due to the AlAsSb electron blocking layer and strong recombination. Although the QE does not degrade when the operating temperature increases to 325 K, the turn-on bias becomes larger at higher temperatures. This behavior was originally attributed to the change in the valence band alignment between the absorber and top contact layers caused by the shift in Fermi level with temperature. In this work, we demonstrated the inadequacy of the original description, and offer a more likely explanation based on temperature-dependent band-bending effects.

SbSI Nanosensors: from Gel to Single Nanowire Devices

NASA Astrophysics Data System (ADS)

Mistewicz, Krystian; Nowak, Marian; Paszkiewicz, Regina; Guiseppi-Elie, Anthony

2017-02-01

The gas-sensing properties of antimony sulfoiodide (SbSI) nanosensors have been tested for humidity and carbon dioxide in nitrogen. The presented low-power SbSI nanosensors have operated at relatively low temperature and have not required heating system for recovery. Functionality of sonochemically prepared SbSI nanosensors made of xerogel as well as single nanowires has been compared. In the latter case, small amount of SbSI nanowires has been aligned in electric field and bonded ultrasonically to Au microelectrodes. The current and photocurrent responses of SbSI nanosensors have been investigated as function of relative humidity. Mechanism of light-induced desorption of H2O from SbSI nanowires' surface has been discussed. SbSI nanosensors have been tested for concentrations from 51 to 106 ppm of CO2 in N2, exhibiting a low detection limit of 40(31) ppm. The current response sensitivity has shown a tendency to decrease with increasing CO2 concentration. The experimental results have been explained taking into account proton-transfer process and Grotthuss' chain reaction, as well as electronic theory of adsorption and catalysis on semiconductors.

Increased brain injury and vascular leakage after pretreatment with p38-inhibitor SB203580 in transient ischemia.

PubMed

Lennmyr, F; Ericsson, A; Gerwins, P; Ahlström, H; Terént, A

2003-11-01

Focal cerebral ischemia activates intracellular signaling pathways including the mitogen-activated protein kinase p38, which may be involved in the process of ischemic brain injury. In this study, the effect of pretreatment with the p38-inhibitor SB203580 on infarct size and blood-brain barrier (BBB) breakdown was investigated with magnetic resonance imaging (MRI). Rats were given SB203580 (n = 6) or vehicle (n = 6) in the right lateral ventricle prior to transient (90 min) middle cerebral artery occlusion (MCAO) on the left side. The rats were examined with serial MRI during MCAO, at reperfusion and after 1 and 4 days. The mean infarct size on T2-weighted images after 1 day was significantly higher in the SB203580-treated group than in controls (300 +/- 95 mm3 vs 126 +/- 75 mm3; P < 0.01). Vascular gadolinium leakage, indicating BBB breakdown, was significantly larger in the SB203580-treated group than in controls after 1 day (median leakage score 18.5; range 15-21 vs 6.5; 4-17; P < 0.05) and 4 days (11; 6-15 vs 3.5; 1-9; P < 0.05), although no significant difference was seen initially. Pretreatment with SB203580 may aggravate ischemic brain injury and cerebral vascular leakage in the present model of transient ischemia.

First principles simulation of amorphous InSb

NASA Astrophysics Data System (ADS)

Los, Jan H.; Kühne, Thomas D.; Gabardi, Silvia; Bernasconi, Marco

2013-05-01

Ab initio molecular dynamics simulations based on density functional theory have been performed to generate a model of amorphous InSb by quenching from the melt. The resulting network is mostly tetrahedral with a minor fraction (10%) of atoms in a fivefold coordination. The structural properties are in good agreement with available x-ray diffraction and extended x-ray-absorption fine structure data and confirm the proposed presence of a sizable fraction of homopolar In-In and Sb-Sb bonds whose concentration in our model amounts to about 20% of the total number of bonds.

The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM

NASA Astrophysics Data System (ADS)

Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

2008-06-01

This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

Enhancement of thermoelectric figure of merit in β-Zn{sub 4}Sb{sub 3} by indium doping control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Pai-Chun, E-mail: pcwei68@gmail.com, E-mail: cheny2@phys.sinica.edu.tw; Hsu, Chia-Hao; Chang, Chung-Chieh

2015-09-21

We demonstrate the control of phase composition in Bridgman-grown β-Zn{sub 4}Sb{sub 3} crystals by indium doping, an effective way to overcome the difficulty of growing very pure β-Zn{sub 4}Sb{sub 3} thermoelectric material. The crystal structures are characterized by Rietveld refinement with synchrotron X-ray diffraction data. The results show an anisotropic lattice expansion in In-doped β-Zn{sub 4}Sb{sub 3} wherein the zinc atoms are partially substituted by indium ones at 36f site of R-3c symmetry. Through the elimination of ZnSb phase, all the three individual thermoelectric properties are simultaneously improved, i.e., increasing electrical conductivity and Seebeck coefficient while reducing thermal conductivity. Undermore » an optimal In concentration (x = 0.05), pure phase β-Zn{sub 4}Sb{sub 3} crystal can be obtained, which possesses a high figure of merit (ZT) of 1.4 at 700 K.« less

Structural transition of (InSb)n clusters at n = 6-10

NASA Astrophysics Data System (ADS)

Lu, Qi Liang; Luo, Qi Quan; Huang, Shou Guo; Li, Yi De

2016-10-01

An optimization strategy combining global semi-empirical quantum mechanical search with all-electron density functional theory was adopted to determine the lowest energy structure of (InSb)n clusters with n = 6-10. A new structural growth pattern of the clusters was observed. The lowest energy structures of (InSb)6 and (InSb)8 were different from that of previously reported results. Competition existed between core-shell and cage-like structures of (InSb)8. The structural transition of (InSb)n clusters occurred at size n = 8-9. For (InSb)9 and (InSb)10 clusters, core-shell structure were more energetically favorable than the cage. The corresponding electronic properties were investigated.

Mononuclear bromide complexes of Sb(V): crystal structures and thermal behaviour

NASA Astrophysics Data System (ADS)

Adonin, Sergey A.; Bondarenko, Mikhail A.; Samsonenko, Denis G.; Semitut, Evgeniy Yu; Sokolov, Maxim N.; Fedin, Vladimir P.

2018-05-01

Reactions of Sb2O3 dissolved in HBr/Br2 and bromides of pyridinium-derived cations result in mononuclear complexes of Sb(V) - (cation)[SbBr6] (cation = 2-chloropyridinium (1), 2-bromopyridinium (2)). Thermal behaviour of 1 and 2, as well as similar previously reported complexes Et4N [SbBr6] (3) and (N-EtPy)[SbBr6] (4), was studied and discussed.

Physicochemical and biological characterization of SB2, a biosimilar of Remicade® (infliximab)

PubMed Central

Hong, Juyong; Lee, Yuhwa; Lee, Changsoo; Eo, Suhyeon; Kim, Soyeon; Park, Seungkyu; Seo, Donghyuck; Lee, Youngji; Yeon, Soojeong; Bou-Assaf, George; Sosic, Zoran; Zhang, Wei

2017-01-01

ABSTRACT A biosimilar is a biological medicinal product that contains a version of the active substance of an already authorized original biological medicinal product. Biosimilarity to the reference product (RP) in terms of quality characteristics, such as physicochemical and biological properties, safety, and efficacy, based on a comprehensive comparability exercise needs to be established. SB2 (Flixabi® and Renflexis®) is a biosimilar to Remicade® (infliximab). The development of SB2 was performed in accordance with relevant guidelines of the International Conference on Harmonisation, the European Medicines Agency, and the United States Food and Drug Administration. To determine whether critical quality attributes meet quality standards, an extensive characterization test was performed with more than 80 lots of EU- and US-sourced RP. The physicochemical characterization study results revealed that SB2 was similar to the RP. Although a few differences in physicochemical attributes were observed, the evidence from the related literature, structure-activity relationship studies, and comparative biological assays showed that these differences were unlikely to be clinically meaningful. The biological characterization results showed that SB2 was similar to the RP in terms of tumor necrosis factor–α (TNF-α) binding and TNF-α neutralization activities as a main mode of action. SB2 was also similar in Fc-related biological activities including antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, neonatal Fc receptor binding, C1q binding, and Fc gamma receptor binding activities. These analytical findings support that SB2 is similar to the RP and also provide confidence of biosimilarity in terms of clinical safety and efficacy. PMID:28005456

Role of the interlayer coupling for the thermoelectric properties of CuSbS2 and CuSbSe2

NASA Astrophysics Data System (ADS)

Alsaleh, Najebah; Singh, Nirpendra; Schwingenschlogl, Udo

The electronic and transport properties of bulk and monolayer CuSbS2 and CuSbSe2 are determined using density functional theory and semi-classical Boltzmann transport theory, in order to investigate the role of the interlayer coupling for the thermoelectric properties. The calculated band gaps of the bulk compounds are in agreement with experiments and significantly higher than those of the monolayers, which thus show lower Seebeck coefficients. Since also the electrical conductivity is lower, the monolayers are characterised by lower power factors. Therefore, the interlayer coupling is found to be essential for the excellent thermoelectric response of CuSbS2 and CuSbSe2 even though it is of weak van der Waals type. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST).

Argon-ion-induced formation of nanoporous GaSb layer: Microstructure, infrared luminescence, and vibrational properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datta, D. P.; Som, T., E-mail: tsom@iopb.res.in; Kanjilal, A.

2014-07-21

Room temperature implantation of 60 keV Ar{sup +}-ions in GaSb to the fluences of 7 × 10{sup 16} to 3 × 10{sup 18} ions cm{sup −2} is carried out at two incidence angles, viz 0° and 60°, leading to formation of a nanoporous layer. As the ion fluence increases, patches grow on the porous layer under normal ion implantation, whereas the porous layer gradually becomes embedded under a rough top surface for oblique incidence of ions. Grazing incidence x-ray diffraction and cross-sectional transmission electron microscopy studies reveal the existence of nanocrystallites embedded in the ion-beam amorphized GaSb matrix up to the highest fluence used inmore » our experiment. Oxidation of the nanoporous layers becomes obvious from x-ray photoelectron spectroscopy and Raman mapping. The correlation of ion-beam induced structural modification with photoluminescence signals in the infrared region has further been studied, showing defect induced emission of additional peaks near the band edge of GaSb.« less

DWPF simulant CPC studies for SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.; Zamecnik, J. R.

2013-06-25

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain themore » Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of

Contactless electroreflectance study of the Fermi level pinning on GaSb surface in n-type and p-type GaSb Van Hoof structures

NASA Astrophysics Data System (ADS)

Kudrawiec, R.; Nair, H. P.; Latkowska, M.; Misiewicz, J.; Bank, S. R.; Walukiewicz, W.

2012-12-01

Contactless electroreflectance (CER) has been applied to study the Fermi-level position on GaSb surface in n-type and p-type GaSb Van Hoof structures. CER resonances, followed by strong Franz-Keldysh oscillation of various periods, were clearly observed for two series of structures. This period was much wider (i.e., the built-in electric field was much larger) for n-type structures, indicating that the GaSb surface Fermi level pinning position is closer to the valence-band than the conduction-band. From analysis of the built-in electric fields in undoped GaSb layers, it was concluded that on GaSb surface the Fermi-level is located ˜0.2 eV above the valence band.

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2011 CFR

2011-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2010 CFR

2010-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2014 CFR

2014-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2013 CFR

2013-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2012 CFR

2012-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

Manufacturable Tri-Stack AlSb/InAs HEMT Low-Noise Amplifiers Using Wafer-Level-Packaging Technology for Light-Weight and Ultralow-Power Applications

DTIC Science & Technology

2009-05-01

shown in Fig. 1 was grown by molecular - beam epitaxy (MBE) on 3-inch semi-insulating GaAs substrates. AlGaSb was used as a buffer. AlSb was used as... beam epitaxy for low-power applications,” J. Vac. Sci. Technol. B. 24, pp. 2581-2585, 2006. [12] Y. C. Chou, L. J. Lee, J. M. Yang, M. D. Lange, P...passivation AlGaSb buffer Figure 1: Cross section of an AlSb/InAs HEMT device on a 3-inch GaAs substrate. The interface region between the

Designing new lithium-excess cathode materials from percolation theory: nanohighways in Li(x)Ni(2-4x/3)Sb(x/3)O2.

PubMed

Twu, Nancy; Li, Xin; Urban, Alexander; Balasubramanian, Mahalingam; Lee, Jinhyuk; Liu, Lei; Ceder, Gerbrand

2015-01-14

Increasing lithium content is shown to be a successful strategy for designing new cathode materials. In layered Li(x)Ni(2-4x/3)Sb(x/3)O2 (x = 1.00-1.15), lithium excess improves both discharge capacity and capacity retention at 1C. Structural studies reveal a complex nanostructure pattern of Li-Sb and Ni-Sb ordering where the interface between these domains forms the correct local configuration for good lithium mobility. The <1 nm Li-Sb stripe domains and their interfaces thereby effectively act as nanohighways for lithium diffusion.

The Enzyme Activity and Substrate Specificity of Two Major Cinnamyl Alcohol Dehydrogenases in Sorghum (Sorghum bicolor), SbCAD2 and SbCAD4.

PubMed

Jun, Se-Young; Walker, Alexander M; Kim, Hoon; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

2017-08-01

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in monolignol biosynthesis, reducing sinapaldehyde, coniferaldehyde, and p -coumaraldehyde to their corresponding alcohols in an NADPH-dependent manner. Because of its terminal location in monolignol biosynthesis, the variation in substrate specificity and activity of CAD can result in significant changes in overall composition and amount of lignin. Our in-depth characterization of two major CAD isoforms, SbCAD2 (Brown midrib 6 [bmr6]) and SbCAD4, in lignifying tissues of sorghum ( Sorghum bicolor ), a strategic plant for generating renewable chemicals and fuels, indicates their similarity in both structure and activity to Arabidopsis ( Arabidopsis thaliana ) CAD5 and Populus tremuloides sinapyl alcohol dehydrogenase, respectively. This first crystal structure of a monocot CAD combined with enzyme kinetic data and a catalytic model supported by site-directed mutagenesis allows full comparison with dicot CADs and elucidates the potential signature sequence for their substrate specificity and activity. The L119W/G301F-SbCAD4 double mutant displayed its substrate preference in the order coniferaldehyde > p -coumaraldehyde > sinapaldehyde, with higher catalytic efficiency than that of both wild-type SbCAD4 and SbCAD2. As SbCAD4 is the only major CAD isoform in bmr6 mutants, replacing SbCAD4 with L119W/G301F-SbCAD4 in bmr6 plants could produce a phenotype that is more amenable to biomass processing. © 2017 American Society of Plant Biologists. All Rights Reserved.

Study for material analogs of FeSb2: Material design for thermoelectric materials

NASA Astrophysics Data System (ADS)

Kang, Chang-Jong; Kotliar, Gabriel

2018-03-01

Using the ab initio evolutionary algorithm (implemented in uspex) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ˜30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb2. Upon doping, the figure of merit becomes larger for FeSbAs than for FeSb2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb2 as a member of a family of compounds (FeSb2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. We also investigate solubility (As or P for Sb in FeSb2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb2.

Study for material analogs of FeSb 2 : Material design for thermoelectric materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Chang-Jong; Kotliar, Gabriel

Using the ab initio evolutionary algorithm (implemented in uspex) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb 2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ~ 30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb 2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb 2. Upon doping, the figure ofmore » merit becomes larger for FeSbAs than for FeSb 2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb 2 as a member of a family of compounds (FeSb 2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. Here, we also investigate solubility (As or P for Sb in FeSb 2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb 2.« less

Study for material analogs of FeSb 2 : Material design for thermoelectric materials

DOE PAGES

Kang, Chang-Jong; Kotliar, Gabriel

2018-03-16

Using the ab initio evolutionary algorithm (implemented in uspex) and electronic structure calculations we investigate the properties of a new thermoelectric material FeSbAs, which is a material analog of the enigmatic thermoelectric FeSb 2. We utilize the density functional theory and the Gutzwiller method to check the energetics. We find that FeSbAs can be made thermodynamically stable above ~ 30 GPa. We investigate the electronic structure and thermoelectric properties of FeSbAs based on the density functional theory and compare with those of FeSb 2. Above 50 K, FeSbAs has higher Seebeck coefficients than FeSb 2. Upon doping, the figure ofmore » merit becomes larger for FeSbAs than for FeSb 2. Another material analog FeSbP, was also investigated, and found thermodynamically unstable even at very high pressure. Regarding FeSb 2 as a member of a family of compounds (FeSb 2, FeSbAs, and FeSbP) we elucidate what are the chemical handles that control the gaps in this series. Here, we also investigate solubility (As or P for Sb in FeSb 2) we found As to be more soluble. Finally, we study a two-band model for thermoelectric properties and find that the temperature dependent chemical potential and the presence of the ionized impurities are important to explain the extremum in the Seebeck coefficient exhibited in experiments for FeSb 2.« less

Unusual Phase Diagram of CeOs 4Sb 12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, P. -C.; Goddard, P. A.; Maple, M. B.

2017-03-01

Filled skutterudite compounds, with the formula MT 4X 12, where M is an alkali metal, alkaline-earth, lanthanide, or actinide, T is Fe, Ru, or Os, and X is P, As, or Sb, display a wide variety of interesting phenomena caused by strong electron correlations [1]. Among these, the three compounds CeOs 4Sb 12, PrOs 4Sb 12, and NdOs 4Sb 12, formed by employing Periodic Table neighbors for M, span the range from an antiferromagnetic (AFM) semimetal (M = Ce) via a 1.85 K unconventional (quadrupolar-fluctuation mediated) superconductor (M = Pr) to a 1 K ferromagnet (FM; M = Nd). Inmore » the course of an extended study of these compounds, we uncovered an unusual phase diagram for CeOs 4Sb 12.« less

Sb lattice diffusion in Si1-xGex/Si(001) heterostructures: Chemical and stress effects

NASA Astrophysics Data System (ADS)

Portavoce, A.; Gas, P.; Berbezier, I.; Ronda, A.; Christensen, J. S.; Kuznetsov, A. Yu.; Svensson, B. G.

2004-04-01

The Sb diffusion coefficient in Si1-xGex/Si1-yGey(001) heterostructures grown by molecular beam epitaxy (MBE) was measured for temperatures ranging from 700 to 850 °C, Ge composition from 0 to 20 % and biaxial pressure from -0.8 (tension) to 1.4 GPa (compression). A quantitative separation of composition and biaxial stress effects is made. We show that the Sb lattice diffusion coefficient: (i) increases with Ge concentration in relaxed layers or at constant biaxial pressure and (ii) increases with compressive biaxial stress and decreases with tensile biaxial stress at constant Ge composition. The enhancement of Sb lattice diffusion in Si1-xGex layers in epitaxy on Si(001) is thus due to the cooperative effect of Ge composition and induced compressive biaxial stress. However, the first effect (composition) is predominant. The activation volume of Sb diffusion in Si1-xGex layers is deduced from the variation of the Sb diffusion coefficients with biaxial pressure. This volume is negative. The sign of the activation volume, its absolute value and its variation with temperature confirm the prediction of the thermodynamic model proposed by Aziz, namely, that under a biaxial stress the activation volume is reduced to the relaxation volume.

The Structural, Photocatalytic Property Characterization and Enhanced Photocatalytic Activities of Novel Photocatalysts Bi2GaSbO7 and Bi2InSbO7 during Visible Light Irradiation

PubMed Central

Luan, Jingfei; Shen, Yue; Li, Yanyan; Paz, Yaron

2016-01-01

In order to develop original and efficient visible light response photocatalysts for degrading organic pollutants in wastewater, new photocatalysts Bi2GaSbO7 and Bi2InSbO7 were firstly synthesized by a solid-state reaction method and their chemical, physical and structural properties were characterized. Bi2GaSbO7 and Bi2InSbO7 were crystallized with a pyrochlore-type structure and the lattice parameter of Bi2GaSbO7 or Bi2InSbO7 was 10.356497 Å or 10.666031 Å. The band gap of Bi2GaSbO7 or Bi2InSbO7 was estimated to be 2.59 eV or 2.54 eV. Compared with nitrogen doped TiO2, Bi2GaSbO7 and Bi2InSbO7, both showed excellent photocatalytic activities for degrading methylene blue during visible light irradiation due to their narrower band gaps and higher crystallization perfection. Bi2GaSbO7 showed higher catalytic activity compared with Bi2InSbO7. The photocatalytic degradation of methylene blue followed by the first-order reaction kinetics and the first-order rate constant was 0.01470 min−1, 0.00967 min−1 or 0.00259 min−1 with Bi2GaSbO7, Bi2InSbO7 or nitrogen doped TiO2 as a catalyst. The evolution of CO2 and the removal of total organic carbon were successfully measured and these results indicated continuous mineralization of methylene blue during the photocatalytic process. The possible degradation scheme and pathway of methylene blue was also analyzed. Bi2GaSbO7 and Bi2InSbO7 photocatalysts both had great potential to purify textile industry wastewater. PMID:28773922

Fermi-surface topologies and low-temperature phases of the filled skutterudite compounds CeOs 4 Sb 12 and NdOs 4 Sb 12

DOE PAGES

Ho, Pei Chun; Singleton, John; Goddard, Paul A.; ...

2016-11-28

We use MHz conductivity, torque magnetometer, and magnetization measurements to report on single crystals of CeOs 4 Sb 12 and NdOs 4 Sb 12 using temperatures down to 0.5 K and magnetic fields of up to 60 tesla. The field-orientation dependence of the de Haas-van Alphen and Shubnikov-de Haas oscillations is deduced by rotating the samples about the [ 010 ] and [ 0more » $$\\bar{1}$$ 1 1 ] directions. Our results indicate that NdOs 4 Sb 12 has a similar Fermi surface topology to that of the unusual superconductor PrOs 4 Sb 12 , but with significantly smaller effective masses, supporting the importance of local phonon modes in contributing to the low-temperature heat capacity of NdOs 4 Sb 12 . By contrast, CeOs 4 Sb 12 undergoes a field-induced transition from an unusual semimetal into a high-field, high-temperature state characterized by a single, almost spherical Fermi-surface section. Furthermore, the behavior of the phase boundary and comparisons with models of the band structure lead us to propose that the field-induced phase transition in CeOs 4 Sb 12 is similar in origin to the well-known α - γ transition in Ce and its alloys.« less

Stability, electronic structures and thermoelectric properties of binary Zn–Sb materials

DOE PAGES

He, Xin; Fu, Yuhao; Singh, David J.; ...

2016-11-03

We report first principles studies of the binary Zn–Sb phases in relation to thermoelectric properties and chemical stability. We identify the unknown structure of the Zn 3Sb 2 phase using particle swarm optimization, finding a tetragonal structure different from the hexagonal Mg 3Sb 2 and the hexagonal or cubic Ca 3Sb 2 phases. All the phases are found to be semiconducting with bandgaps in the range of 0.06–0.77 eV. This semiconducting behavior is understood in Zintl terms as a balance between the Zn:Sb and Sb 3-:½(Sb 2) 4- ratios in the stable crystal structures. With the exception of Zn 3Sbmore » 2, which has a small gap, all the compounds have electronic properties favorable for thermoelectric performance.« less

Effect of arsenic on the optical properties of GaSb-based type II quantum wells with quaternary GaInAsSb layers

NASA Astrophysics Data System (ADS)

Janiak, F.; Motyka, M.; Sek, G.; Dyksik, M.; Ryczko, K.; Misiewicz, J.; Weih, R.; Höfling, S.; Kamp, M.; Patriarche, G.

2013-12-01

Optical properties of molecular beam epitaxially grown type II "W" shaped GaSb/AlSb/InAs/GaIn(As)Sb/InAs/AlSb/GaSb quantum wells (QWs) designed for the active region of interband cascade lasers have been investigated. Temperature dependence of Fourier-transformed photoluminescence and photoreflectance was employed to probe the effects of addition of arsenic into the original ternary valence band well of GaInSb. It is revealed that adding arsenic provides an additional degree of freedom in terms of band alignment and strain tailoring and allows enhancing the oscillator strength of the active type II transition. On the other hand, however, arsenic incorporation apparently also affects the structural and optical material quality via generating carrier trapping states at the interfaces, which can deteriorate the radiative efficiency. These have been evidenced in several spectroscopic features and are also confirmed by cross-sectional transmission electron microscopy images. While arsenic incorporation into type II QWs is a powerful heterostructure engineering tool for optoelectronic devices, a compromise has to be found between ideal band structure properties and high quality morphological properties.

Thermoelectric properties of AMg 2X 2, AZn 2Sb 2 (A = Ca, Sr, Ba; X = Sb, Bi), and Ba 2ZnX 2 (X = Sb, Bi) Zintl compounds