顺式二(乙二胺)二硝基合钴(Ⅲ)酒石酸锑盐晶体结构和分子的绝对构型

顺式二(乙二胺)二硝基合钴(Ⅲ)酒石酸锑盐，Δ-cis-［Co(en)₂(NO₂)₂］₂-d-［Sb₂(C₄H₂O_{6)2］·2H2O，是由酒石酸锑钾对外消旋混合物cis-［Co(en)2(NO2)2］Cl进行拆分的产物。标题化合物(Sb2Co2C16N12O22H40)的晶体结构由衍射方法确定。晶体学参数为：正交晶系，空间群P212121,a=10.033(5), b=13.203(2),c=25.928(7)(),V=3434(2)^{3,Z=4,Mr=1114.06, Dc=2.156Mgm-3,μ=21.07 mm-1,F(000)=2208, R=0.072,RW=0.084。结构表明，分子由2个Co(Ⅲ)配离子和一个酒石酸锑阴离子及两个水分子组成，阴离子为一双核螯合离子。Sb原子一对孤对电子与其周围四个配位氧原子形成变形三角双锥结构。通过Co和Sb原子对CuKα射线的反常散射效应确定了分子的绝对构型。二个Co(Ⅲ)离子均为Δ构型，酒石酸锑阴离子为R构型。结构分析表明，标题化合物中三点接触离子对在手性识别中起重要作用。}}     

Adsorption of ammonia on vanadium-antimony mixed oxides

We analyzed the adsorption of ammonia (NH₃) on the VSbO₄(1 1 0) catalyst surface using density functional theory (DFT) calculations. We followed the evolution of the chemical bonds between different atoms of the resulting NH₃/VSbO₄ system and the changes in the electronic structure of the catalyst. NH₃ preferential adsorption geometries were analyzed through the crystal orbital overlap population (COOP) concept and the density of states (DOS) curves. The VSbO₄(1 1 0) surface exhibits Lewis and Brønsted acid sites on which the ammonia molecule can interact. On the Lewis acid site, NH₃ adsorption resulted in the interaction between the N and a surface V-isolated cation. On Brønsted acid site, N interacted with a surface H coming from the chemical dissociation of water. The COOP analysis indicate that NH₃ interaction on the VSbO₄(1 1 0) surface is weak. In addition, the DOS curves show more developed electronic interactions for NH₃ adsorption on Lewis acid site than over Brønsted acid site.     

氢化物发生-原子荧光光谱法同时测定纺织品中的砷和锑

湿法消化样品,断续流动-无色散氢化物发生-原子荧光光谱法同时测定纺织品中的砷,研究了酸度、KBH4浓度、仪器主要条件参数对实验结果的影响,以及硫脲 抗坏血酸混合液对干扰元素的消除作用。在经过优化的实验条件下,本方法砷和锑的精密度分别为1.69%和2.75%,检出限分别为0.5605μg·L-1和0.4670μg·L-1,方法的加标回收率在94.71%—96.85%之间,该方法能简单快速、准确的测定纺织品中砷和锑的残留量。     

单根Sb掺杂ZnO微米线非平衡电桥式气敏传感器的制作与性能

通过使用化学气相沉积法,成功制备出超长、大尺寸的Sb掺杂ZnO微米线.基于非平衡电桥原理,利用单根Sb掺杂ZnO微米线作为非平衡电桥的一个桥臂,制作出了可以在室温环境下工作的气敏传感器原型器件.结果表明:室温下测得该传感器对20,50,100和200 ppm(1 ppm=10^-6)不同浓度的丙酮及乙醇气体的响应-恢复曲线均呈现为矩形形状,在空气及被测气体中均有稳定的电流值,并随着探测气体浓度的增大,器件的响应值也在逐渐增加.此外,还发现器件对丙酮气体具有更好的选择性,当丙酮气体浓度为200 ppm时,该传感器的响应时间为0.2 s,恢复时间为0.3 s,响应度高达243%.通过与普通电导式气敏传感器对比发现,采用这种非平衡电桥结构传感器可以明显地提高响应度,使响应和恢复时间更快.此外,还研究了器件的气体探测机理.     

Evaluation of Thermoelectric Properties of Ag0.366Sb0.558Te

Ternary AgSbTe₂ materials are frequently reported to show a promising thermoelectric performance, due to the intrinsically low lattice thermal conductivity and complex valence band structure. However, stoichiometric AgSbTe₂ is found to be thermodynamically unstable and would partially decompose into Ag₂Te and Sb₂Te₃ during thermal cycling. Instead, Ag_0.366Sb_0.558Te is the composition for stabilizing the single-phase according to the Ag₂Te-Sb₂Te₃ phase diagram, while the thermoelectric transport properties have rarely been reported and are the focus of this work. Sn/Sb substitution is found to effectively increase not only the carrier concentration from ≈5 × 10¹⁹ cm⁻³ to ≈4 × 10²¹ cm⁻³, but also the density-of-states effective mass, leading to an enhanced Seebeck coefficient along with a decreased carrier mobility. Single parabolic band (SPB) model with acoustic phonon scattering enables a good understanding on the charge transport. The increased carrier concentration effectively suppresses the bipolar effect at high temperatures. As a result, a peak zT of ≈1.3 and an average of ≈0.9 are achieved.     

Proximity-Effect-Induced Superconductivity in Nb/Sb2Te3-Nanoribbon/Nb Junctions

Nanohybrid superconducting junctions using antimony telluride (Sb₂Te₃) topological insulator nanoribbons and Nb superconducting electrodes are fabricated using electron beam lithography and magnetron sputtering. The effects of bias current, temperature, and magnetic field on the transport properties of the junctions in a four-terminal measurement configuration are investigated. Two features are observed. First, the formation of a Josephson weak-link junction. The junction is formed by proximity-induced areas in the nanoribbon right underneath the inner Nb electrodes which are connected by the few tens of nanometers short Sb₂Te₃ bridge. At 0.5 K a critical current of 0.15 µA is observed. The decrease of the supercurrent with temperature is explained in the framework of a diffusive junction. Furthermore, the Josephson supercurrent is found to decrease monotonously with the magnetic field indicating that the structure is in the small-junction limit. As a second feature, a transition is also observed in the differential resistance at larger bias currents and larger magnetic fields, which is attributed to the suppression of the proximity-induced superconductive state in the nanoribbon area underneath the Nb electrodes.     

溅射气压对Ge2Sb2Te5薄膜光学常数的影响

实验研究了氩气气压对溅射制备的Ge2 Sb2 Te5 薄膜的光学常数随波长变化的影响 ,结果表明 :随薄膜制备时氩气气压的增加 ,Ge2 Sb2 Te5 薄膜的折射率n先增大后减小 ,而消光系数k先减小后增大。二者都随波长的变化而变化 ,且在长波长范围变化较大 ,短波长范围变化较小 ,解释了溅射气压对Ge2 Sb2 Te5 薄膜的光学常数影响的机理     

具有不同扩散势垒的p型(Bi1-0.85Sb0.85)和PbTe二元梯度热电材料的研制

在分析了热电材料的发展背景和研究理论的基础上,采用热压法制备出单体和双层具有不同扩散势垒的（Ｂｉ１－０．８５Ｓｂ０．８５）２Ｔｅ３与ＰｂＴｅ体系二元梯度热电材料,金属,Ｆｅ、Ｎｉ和Ｍｇ被用作层间扩散势垒材料,测定了它们的热电性能,分析了它们的物质组成和各层内和层间的成分分布,确定出较好的扩散势垒材料为金属铁和钴。     

Behaviour of the Different Oxydation States of As,Sb, Se and Sn Using Dithiocarbamates for Their Separation from Environmental,Food and Drug Samp1es

The mentioned elements are known to occur in the environment in different oxydation states with different biological activities.

Speciation of the oxydation state by selective enrichment can lead to relevant information for the toxicologist.

-allows to discriminate between the oxidation states of the mentioned elements

-converts the elements to the optimum oxydation state for enrichment from the sample

-brings the elements in an ideal form for their determination by x-ray fluorescence analysis using coprecipitation with the dibenzyl-ammoniumsalt of dibenzyldithiocarbamic acid.

An outline of the method, instrumentation used and applications to organic, biological and environmental samples is given.