改性竹炭对水溶液中Cu(Ⅱ)、Cd(Ⅱ)的吸附性能

采用不同方法对竹炭进行改性,寻求吸附效果最好的改性产品,并研究其对溶液中Cu2+、Cd2+的吸附性能,考察了吸附时间、溶液pH值、吸附温度和溶液初始浓度对吸附效果的影响,同时与未改性竹炭的吸附性能进行了对比。实验结果表明:相同条件下,氧化改性竹炭对Cu2+、Cd2+的吸附效果明显优于其他方法改性竹炭和未经改性的竹炭。吸附温度为15℃、25℃、45℃时,氧化竹炭对Cu2+的最大吸附量分别为6.653mg/g、6.702mg/g和7.897mg/g,而氧化竹炭对Cd2+的最大吸附量分别为1.700mg/g、1.826mg/g和2.282mg/g。氧化改性竹炭对Cu2+、Cd2+的吸附均符合Freundlich方程和Langmuir方程。实验证明,氧化竹炭是一种应用前景广泛的重金属离子吸附剂。     

Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.     

Compositional analysis and optical properties of Ag-doped ITO films

ITO and Ag-ITO composite films were deposited on glass substrates by DC magnetron sputtering. Scanning electron microscope images indicated that Ag existed in the form of nanoparticles. X-ray photoelectron spectroscopic analysis illustrated that both Ag doping and heat treatment had obvious influence on the composition and element chemical state of the films. Ag doping dramatically decreased the transmittance of the film. But after being annealed, Ag-ITO films exhibited the high average transmittance of 80-90% in visible wavelength range. By using the spectroscopic ellipsometry optimization, the optical constants were extracted from the transmittance spectra. The results suggested the potential use of Ag-ITO films for antireflection coating system.     

ZnO:Cd薄膜光学性能的研究

本文以载玻片、石英为基底,采用控制掺杂方法,制备了ZnO:Cd薄膜,通过热处理方法获得了优良性能的ZnO:Cd薄膜。研究分析了镉浓度为2%-10%时ZnO薄膜的透射光谱。结果表明,有较强的紫外发射峰,但没有深能级发射,未出现其它的发射峰,说明ZnO:Cd薄膜在紫外线区的发射占主导地位,表明带间跃迁占主导地位。     

Hanle Effect Measurements of Spin Lifetime in Zn0.4Cd0.6Se Epilayers Grown on InP

We use the Hanle effect to study spin relaxation in Zn_xCd_1–xSe epilayers grown on lattice-matched InP substrates. We study three samples with a fixed composition (x = 0.4) and with varying levels of n-doping, as well as an undoped sample with x = 0.5. Our measurements show that the spin relaxation time changes non-monotonically as a function of carrier density, with a maximum transverse spin lifetime of ~10.5 ns at low temperatures for a sample doped near the metal–insulator transition.     

高铜锌精矿处理的研究与实践

某厂一系统采用传统的湿法炼锌工艺。高铜锌精矿的处理量加大后，上清[Cu^2 ]达600mg／L左右，严重影响一段净化质量和一段净化后液的压滤速度，采用预除铜工艺。即可消除[Cu^2 ]过高的影响。     

A complete quantitative model of the isothermal vapor phase epitaxy of (Hg,Cd)Te

A quantitative model of isothermal vapor phase epitaxy is proposed. It can be applied to both closed and open tube systems. This model enables the prediction of compositional profiles of the layers grown by isothermal vapor phase epitaxy with dependence on the growth parameters and thermodynamical data of the (Hg,Cd)Te system. The dependence of compositional profiles of the ISOVPE layers on temperature and time of deposition, source to substrate spacing, mercury and inert gas pressures are discussed for both solid and liquid sources. Modification of the compositional profiles by the postgrowth annealing has also been studied. The proper choice of growth and annealing parameters makes the optimization of the profiles possible. The calculated profiles are compared with the experimental data and a satisfactory quantitative fit is found in most cases. The possible reasons for remaining discrepancies are discussed.     

超热中子活化分析的进一步研究

本文建议用一个一般化有利因子F=G~(1/2)R~(1/2)/R,来真实地反映超热中子活化导致的探测极限或计数统计的实际改善。经典的Brune定义和近来提出的Bem定义,可以分别看作本定义在G=R和G=1时的特例。为了得到最佳有利因子,推荐在不同孔道(甚至不同的堆)上分别进行全堆谱中子活化(TNA)和超热中子活化(ENA)。本文还全面评价了镉和氮化硼屏蔽体的利弊。此外,测定了38个反应,H_4孔道中ENA对于15～2孔道中TNA的有利因子。最后,对33个干扰反应,给出了在这两种照射条件下的干扰因子,并讨论了ENA的干扰放大。     

Growth conditions of the cubic phase cBN in boron nitride films

The nucleation and the subsequent coalescence period of the cubic phase cBN in sputter deposited BN-films is characterized by a shrinking of the film thickness. This is due to the transition of hBN into the denser cBN-phase which occurs inside a highly textured hBN base layer. The corresponding variation of the film thickness with the deposition time is described by a quantitative model. Full BN-stoichiometry in the hBN base layer is shown to be a mandatory condition for the nucleation process and the following growth of the cubic BN-phase. An increase of the substrate temperature fosters the incorporation of nitrogen into the growing film and, thus, the achievement of the stoichiometry condition.     

垂直布里奇曼法生长的Cd_（0.8）Mn_（0.2）Te单晶体中Te沉淀相分析

Cd1-xMnxTe（CdMnTe,CMT）是制备光学隔离器、太阳能电池、x射线和γ射线探测器的优选材料。本实验采用垂直布里奇曼（VB）法成功地生长出Cd0.8Mn0.2Te单晶体。用JEM-3010型高分辨透射电子显微镜（HRTEM）观察了CMT晶体中的纳米级Te沉淀。选区电子衍射得到了Te沉淀与CMT基体两相的合成电子衍射图。计算出单斜Te沉淀的晶胞参数为：a=0.31nm,b=0.79nm,c=0.47nm,β=92.71°。确定了Te沉淀和CMT基体的取向关系为（0 31）Te//（202）CMT,[100]Te//[111]CMT。最后,对Te沉淀（缺陷）的形成原因进行了分析。