Reduced Shell Model Calculations of ^111Sb and ^112Sb

The low-lying states of the mid-heavy odd-even ^111Sb and odd-odd ^112Sb isotopes are calculated for the first time within the shell model framework. The shell model calculations have been carried out within the reduced model space including the single particle orbits ld5/2,097/2, ld3/2, 2Sl/2. We obtain the energy spectra for the ^111Sb and ^112Sb isotopes in the reduced model space by using CD-Bonn two-body effective nucleon-nucleon interaction. The energy spectra are compared to the experimental results to give some discussion about the low-lying states of ^111Sb and ^112Sb.     

On the role of Sb excess in Fe–Sb oxides based catalysts

Fe–Sb oxide catalysts with different amounts of Ti were prepared by coprecipitation technique. The stability of the systems is described in terms of the phases formed as a function of the calcination temperature, the Ti content and the use in the reactor.     

ICP-AES测定钛白粉中的Sb和P

(NH4) 2 SO4- H2 SO4快速消解钛白粉 ,ICP- AES法测定钛白粉中的 Sb和 P,该方法快速、简便、准确 ,方法的精密度为 1.0 3%— 4 .4 5 % ,加标回收率为 95 .0 %— 10 1.6 % ,在钛白粉日常检验中具有重要的实际意义     

超声波辅助提取-HG-ICP-AES法测定中草药雷公藤中可溶态Sb(Ⅲ)和Sb(Ⅴ)

本文建立了用超声波辅助提取,氢化物发生-电感耦合等离子体原子发射光谱法测定中草药雷公藤中可溶态Sb(Ⅲ)和Sb(Ⅴ)的分析方法。研究了超声波辅助提取的影响因素、锑形态分离的最佳pH值、仪器工作条件对锑氢化物发生的影响及五价锑的还原条件,探讨了共存离子对锑测定的干扰及消除方法。Sb(Ⅲ)和Sb(Ⅴ)的检出限分别为0.3和2.4 μg·L-1, 相对标准偏差分别为3.9%和4.5%,样品加标回收率为93%～105%。     

掺Sb纳米ZnO的光致发光的研究

用柠檬酸盐法合成了不同掺杂浓度的纳米ZnO,粒径约为15nm。探讨了Sb掺杂对ZnO光致发光峰的影响。随着掺杂量的提高,样品的发射峰从428nm移至444nm。未掺杂ZnO的发光主要是源于电子从锌填隙形成的缺陷能级到价带顶的跃迁;随着掺杂量的提高,体系的氧空位增加,从而使得电子从氧空位所形成的缺陷能级到价带顶的跃迁占据主导,光致发射峰向长波方向移动。     

Electrical resistivity of liquid Sb–Zn alloys

Using the DC four-probe method, temperature dependence of the electrical resistivity (ρ???T) of Sb_{100? x} Zn _x (x?=?25,?40,?50,?57,?61,?80 at%) alloys was investigated in the temperature range of 500–860°C. The results showed that resistivity of each liquid alloy decreased non-linearly with temperature increasing above their liquidus (T _L) until reaching critical temperature, at which the resistivity–temperature coefficients dρ/dT–T converts from negative into positive. The phenomena of liquid phase transformation might relate with the dissociation of covalent bonds, chemical orders and associations in Sb–Zn melts.     

氢化物发生-原子荧光光谱法直接测定土壤水溶态Sb(Ⅲ)和Sb(Ⅴ)

在HCl介质中,Sb(Ⅲ)和Sb(Ⅴ)在氢化物发生过程中的化学反应效率不同,通过测定经还原剂还原后和还原前Sb的荧光强度,求解联立方程计算出Sb(Ⅲ)和Sb(Ⅴ)的含量,据此建立了氢化物发生-原子荧光光谱法直接测定土壤水溶态Sb(Ⅲ)和Sb(Ⅴ)方法,操作简便,实用性强。考察了HCl浓度和KBH₄浓度对Sb(Ⅲ)和Sb(Ⅴ)测定灵敏度的影响以及共存元素的干扰情况,并比较了两种还原剂对Sb(Ⅴ)的还原效果。方法检出限为Sb(Ⅲ)1.11 ng·g-1 ,Sb(Ⅴ)1.57 ng·g-1。加标回收试验表明方法准确、可靠。     

含Sb的Bi系超导体的研究

Bi-Sr-Ca-Cu-O系中掺入适量的Sb,其高温相(110K相)含量明显多于不掺Sb样品。Sb具有加速高温相形成的作用。对于各义组分为Bi_2-xSb_xSr₂Ca_2.5Cu_3.7O_y的样品,x=0.1最有利于高温相的形成。用液氮中淬火后低温回火的方法,发现在865℃烧结时样品中首先形成的是低温相(80K相),然后再逐渐转变为高温相。T_c值随烧结时间的延 关键词：     

Electrical resistivity of liquid Bi–Sb alloys

The electrical resistivities of liquid Bi–Sb alloys have been measured by DC four-probe method within Bi-rich composition through a wide temperature range. The distinct anomaly of a hump shape was observed on resistivity–temperature (ρndash;T) curves for liquid Bi–Sb alloys on heating at the relatively high temperatures. These anomalies have revealed the temperature-induced liquid–liquid phase transition in Bi–Sb melts. The DSC results for BiSb20wt% alloy further prove the existence of liquid–liquid transition. Measuring the ρ–T curves first on heating and then on cooling we have found that on cooling the ρ–T curve remained linear. It means that the postulated liquid–liquid transition may be irreversible.     

Effect of 0h11/2 Level on Shell Model Calculations of ^105Sb and ^107Sb

The full and reduced shell model calculations have been carried out for the light odd-even ^105Sb and ^107Sb isotopes. The model space has been chosen as 1d5/2, 0g7/2, 1d3/2, 2s1/2, and 0h11/2 for the full calculations and excluded 0h11/2 for the reduced calculations. The reduced shell model calculations of ^105Sb and ^107Sb isotopes are presented for the first time. We obtain the energy spectra for the ^105Sb and ^107Sb isotopes in the full and reduced model space by using CD-Bonn two-body effective nucleon-nucleon interaction. The resulting energy spectra are compared to the experimental results to understand the effect of the 0h11/2 level on the shell model calculations. We draw conclusions about the right model space in the shell model calculations for the isotopes around the N =Z= 50 region of the periodic table.     

立方K2CsSb、K3Sb和Cs3Sb阴极材料的电子结构和光学性质

针对K2CsSb光电阴极生长过程中可能存在的K3Sb、K2CsSb和Cs3Sb三种化合物,采用基于密度泛函理论的第一性原理计算方法,分别建立这三种锑化物阴极材料的立方结构体模型和(111)表面模型,获得了其电子结构与光学性质.对于体模型,计算得到了能带结构、态密度和光学性质,而对于表面模型,计算得到了功函数、光学性质和表面能.结果表明,三种锑化物阴极在中微子与闪烁体作用辐射能量范围(2.4~3.2eV)内,K2CsSb体材料的吸收系数和反射率与Cs3Sb、K3Sb体材料相近,而K2CsSb(111)表面的吸收系数和反射率低于其他两种阴极的(111)表面.此外,K3Sb的禁带宽度最小、功函数最大且表面能最大,Cs3Sb的表面能最小,其功函数与K2CsSb相近但禁带宽度比K2CsSb小,而K2CsSb禁带宽度最大,功函数和表面能都较小,因此K2CsSb阴极在蓝紫光波段适合作为一种稳定高效的光电发射材料.     

Multiple-State Storage Capability of Stacked Chalcogenide Films （Si16Sb33Te51/Si4Sb45Te51/Si11Sb39Te50） for Phase Change Memory

The multiple-state storage capability of phase change memory （PCM） is confirmed by using stacked chalcogenide films as the storage medium. The current-voltage characteristics and the resistance-current characteristics of the PCM clearly indicate that four states can be stored in this stacked film structure. Qualitative analysis indicates that the multiple-state storage capability of this stacked film structure is due to successive crystallizations in different Si-Sb-Te layers triggered by different amplitude currents.     

Temperature-resolved synchrotron X-ray diffraction of nanocrystalline titania in solvent: the effect of Cr–Sb and V–Sb doping

Nanocrystalline titania pigments were produced by high temperature-forced hydrolysis in a coordinating high-boiling solvent (and water for reference). The effect of synthesis conditions and co-doping with Cr–Sb and V–Sb on particle size and anatase-to-rutile transformation (A → R) was studied by temperature-resolved synchrotron X-ray diffraction. The experiments were performed directly on low concentration (3.5 vol.%) as-synthesized suspensions of titania nanoparticles (up to 230 °C) and on the corresponding dried powders (up to 950 °C). Crystallite size of as-synthesized nano-anatase is around 20 nm (glycol) or 70 nm (water); it exhibits a slow growth rate up to the onset temperature of the A → R. Phase composition and crystallite size are drastically influenced by both synthesis conditions and doping. Synthesis in water resulted in the simultaneous occurrence of anatase and brookite; transformation into rutile begins early but with a slower rate with respect to glycol-based samples. Doping affected the A → R, whose onset temperature in undoped titania (700 °C) was lowered to 650 °C (V–Sb) or prevented up to 950 °C (Cr–Sb). Both (V–Sb) and (Cr–Sb) dopings reduced the volume thermal expansion rate of anatase.     

Thermoelectric properties of mechanically alloyed Bi–Sb alloys

Homogeneous polycrystalline Bi_100-xSb_x (x=12, 15, 22) alloys were synthesized by mechanical alloying. The transport coefficients (electrical resistivity, thermal conductivity, and thermopower) were measured, in the 77–300 K temperature range, on samples consolidated either by sintering or extrusion. The thermoelectric figure of merit was deduced from the three coefficients. The temperature dependences are discussed as a function of the alloys’ microstructures taking into account the qualitative effect of potential barriers. Extrusion leads to better performing thermoelectric materials than does sintering. The highest figure of merit is reached for temperatures around 150 K, a temperature at which no reliable thermoelectric material of long service life is available until now. Received: 11 November 1998 / Accepted: 5 January 1999 / Published online: 24 March 1999     

Impurities in type-II-staggered InAs/AℓSb superlattices

The physics of impurities in Type-II staggered superlattices is reviewed, with emphasis on changes of doping character, such as shallow to deep and deep to false-valence transitions, that can result from altering layer thicknesses. It is shown how some impurities can change their doping characters from "deep acceptors" (semi-insulating) to shallow donors (n-type) as functions of layer thicknesses in superlattices such as InAs/AℓSb. A particularly important case is an Aℓ_Sb antisite defect in an AℓSb layer of an InAs/AℓSb superlattice. This defect is a deep trap or "deep acceptor" in AℓSb, and a remote donor in some superlattices, depending on the layer thicknesses. It can, by itself, control the electron gas density in a superlattice structure, and so can play an important role in the development of high-speed field-effect transistors.     

“Antisite” incorporation of Sb dopant in GaN

Radioactive ¹¹⁹Sb was implanted in an undoped GaN single crystal and Mössbauer spectra were taken of the 23.8 keV gamma rays of ¹¹⁹Sn emitted in its decay. A comparison with Mössbauer spectra of ¹¹⁹Sb implantated in other III-V compounds leads to the conclusion that Sb in GaN lands in the Ga site in contrast to all common III-V compounds, where Sb occupies the anion site. Calculations of electronegativity differences for Sb incorporation in either Ga or N site support our interpretation of the experimental data.     

掺Sb对PbWO_4晶体发光性能的改善

首次报道了ＰｂＷＯ４：Ｓｂ的光谱特性,包括透射谱和Ｘｅ灯光源激发的发射谱与激发谱．掺Ｓｂ具有增强绿光带、抑制红光带并大幅度提高光产额的效果．通过与空气退火ＰＷＯ发光的比较,对绿光带的起因、Ｓｂ掺杂的作用也进行了简要的讨论．     

ZnO：Sb薄膜的光致发光及拉曼特性研究

利用射频磁控溅射法（MS．RF）在玻璃基片上制备了不同掺杂浓度的ZnO：Sb薄膜．借助X射线衍射仪（XRD）、透射光谱、光致发光谱（PL）和拉曼散射光谱（Raman）等手段研究了Sb掺杂浓度对ZnO薄膜的微结构、光致发光和拉曼特性的影响．结果表明：所有样品均呈现ZnO六角纤锌矿结构且具有高度C轴择优取向;在Sb掺杂ZnO薄膜的拉曼光谱中观察到位于532cm^-1的振动模式,结合XRD分析认为此峰归因于Sb替代Zn位且与0成键的局域振动模式（LVMSb--O）;光致发光谱测试发现,仅在ZnO：Sb薄膜中观察到位于3．11eV附近的紫光发射峰,结合拉曼光谱分析认为此峰与XbZn-O复合体缺陷相关．