CO2加氢低压合成甲醇催化剂CuO／ZnO／ZrO2的光电子能谱研究

本文应用XPS和XAES(X光激发俄歇电子能谱)考察了CO_2加氢低压合成甲醇用CuO/ZnO/ZrO_2催化剂在反应条件下的表面状态。结果表明,在还原及反应状态下,催化剂表面没有稳定的Cu~(2+)、Cu~+离子存在,仅有Cu~0能被检测到;ZnO部分被还原,产生低价锌Zn~[(2-δ)](0<δ<2)物类。结合活性测试结果,认为高活性、高选择性的CO_2加氢合成甲醇催化剂要以Cu、Zn共同存在为前提,即Cu~0与部分还原的ZnO共同组成甲醇合成的活性中心。     

含硫、氮Schiff碱配合物—二水二分之一二甲基亚砜醋酸四邻香草醛缩胺基硫脲合镉（Ⅱ）的合成及晶体结构

Ｘ射线单晶衍射结果表明，三核镉配合物Ｃｄ３［ＣＨ３Ｏ（Ｏ）Ｃ６Ｈ３ＣＨ＝ＮＮＨＣ（Ｓ）ＮＨ２］４·［ＣＨ３ＣＯＯ］２·１／２［ＣＨ３Ｓ（Ｏ）ＣＨ３］·２Ｈ２Ｏ为单斜晶系，空间群为Ｃ２／ｃ，ａ＝３．４２１４（４），ｂ＝１．１５８１（２），ｃ＝１．７９３２（５）ｎｍ，β＝１１９．７６（１）°，Ｖ＝６．１６８ｎｍ３，Ｍｒ＝１４２７．４３，Ｚ＝４，Ｄｃ＝１．５４ｇ／ｃｍ３，μ＝１２．４８ｃｍ（－１），Ｆ（０００）＝２８６０，最后偏离因子Ｒ＝０．０６６．     

Numerical multilinear algebra and its applications

Numerical multilinear algebra (or called tensor computation), in which instead of matrices and vectors the higher-order tensors are considered in numerical viewpoint, is a new branch of computational mathematics. Although it is an extension of numerical linear algebra, it has many essential differences from numerical linear algebra and more difficulties than it. In this paper, we present a survey on the state of the art knowledge on this topic, which is incomplete, and indicate some new trends for further research. Our survey also contains a detailed bibliography as its important part. We hope that this new area will be receiving more attention of more scholars.      

Fragment-Based Ab Initio Molecular Dynamics Simulation for Combustion

We develop a fragment-based ab initio molecular dynamics (FB-AIMD) method for efficient dynamics simulation of the combustion process. In this method, the intermolecular interactions are treated by a fragment-based many-body expansion in which three- or higher body interactions are neglected, while two-body interactions are computed if the distance between the two fragments is smaller than a cutoff value. The accuracy of the method was verified by comparing FB-AIMD calculated energies and atomic forces of several different systems with those obtained by standard full system quantum calculations. The computational cost of the FB-AIMD method scales linearly with the size of the system, and the calculation is easily parallelizable. The method is applied to methane combustion as a benchmark. Detailed reaction network of methane reaction is analyzed, and important reaction species are tracked in real time. The current result of methane simulation is in excellent agreement with known experimental findings and with prior theoretical studies.     

一类质量—黏弹性弹簧系统的简谐受迫振动

研究一类质量－弹簧系统的简谐受迫振动。弹簧为黏弹性材料，其特性由分数导数型本构关系描述。求出了系统的稳态响应，并讨论了材料黏性系数对幅频特性的影响。     

三维复合介质波动方程多尺度辛几何算法

本文针对三维复合介质波动方程,提出了一类多尺度辛几何算法.其主要内容有:1.快速振荡系数三维波动方程的多尺度渐近分析与收敛性估计;2.均匀化波动方程的辛几何算法;3.多尺度辛几何算法与数值实验结果.     

Second-order nonlinear least squares estimation

The ordinary least squares estimation is based on minimization of the squared distance of the response variable to its conditional mean given the predictor variable. We extend this method by including in the criterion function the distance of the squared response variable to its second conditional moment. It is shown that this “second-order” least squares estimator is asymptotically more efficient than the ordinary least squares estimator if the third moment of the random error is nonzero, and both estimators have the same asymptotic covariance matrix if the error distribution is symmetric. Simulation studies show that the variance reduction of the new estimator can be as high as 50% for sample sizes lower than 100. As a by-product, the joint asymptotic covariance matrix of the ordinary least squares estimators for the regression parameter and for the random error variance is also derived, which is only available in the literature for very special cases, e.g. that random error has a normal distribution. The results apply to both linear and nonlinear regression models, where the random error distributions are not necessarily known.     

EAST托卡马克杂质输运蒙特卡洛模拟

介绍DIVIMP程序的基本思想和采用的物理模型,研究EAST托卡马克欧姆放电条件下碳杂质的产生与输运.模拟结果与实验测量具有较好的一致性,说明将该程序应用于EAST装置中杂质输运模拟的合理性.并利用DIVIMP程序预测EAST在8MW加热功率条件下钨杂质的输运特性.     

十六烷基三甲基溴化铵/聚乙二醇辛基苯基醚微乳液凝胶固定化脂肪酶催化水解消旋布洛芬辛酯

初步考察了水溶液中影响十六烷基三甲基溴化铵（CTAB）/聚乙二醇辛基苯基醚（TX-100）微乳液凝胶（MBG）固定化脂肪酶催化水解消旋布洛芬辛酯的主要因素。 结果表明,CTAB/TX-100 MBG固定化脂肪酶在水溶液中能顺利催化水解S-构型布洛芬辛酯生成S-构型布洛芬。 随TX-100在EM（正丁醇与TX-100的混合物）中含量的增加,反应转化率（X）逐渐增大,而产物中S-构型布洛芬的对映体过量值（eei）有少许的降低;随凝胶含水量的增加,X及eei均呈钟罩形变化,二者最大值时对应的凝胶水含量为27.3%,且磷酸缓冲溶液对二者的影响要比溶解明胶的水大;X在反应初期（16 h内）增加明显,随反应时间的继续延长增加缓慢,24 h后趋于平衡,而eei随反应时间的延长呈逐渐降低的趋势;随固定化脂肪酶重复使用次数的增多,X在前3次中降幅不大,后几次中降幅逐渐增大,eei则呈逐渐稍微降低的趋势,重复使用10次后,二者分别降低了36.55%和0.52%。     

弹性反冲探测分析技术在材料氦行为研究中的应用

弹性反冲探测分析技术（ERDA）对轻元素的测定具有灵敏度高、包含深度信息的优势,因此在材料氦行为研究中发挥着重要作用。镍基哈氏N合金被认为是未来熔盐堆的结构材料,氦脆是其服役性能下降的主要因素之一。利用掠入射模式的ERDA,解析了哈氏N合金样品中的氦原子浓度及其分布,但仅局限于0~175 nm深度范围内。结果表明:在800℃的退火条件下,距离样品辐照表面~33 nm深度区域内,出现了氦原子逃逸现象。更高温度的退火（1 050℃）可加剧氦原子的逃逸,但样品中仍有氦原子滞留。另外,采用透射式的ERDA,极大地扩大了对氦原子分析的深度范围,得到了纯镍薄膜在0~950 nm深度区域内的氦原子浓度分布。这表明将块体材料制备成薄膜样品,利用透射模式的ERDA,将可以得到氦原子在更大范围内的扩散、逃逸行为。Since the elastic recoil detection analysis (ERDA) technique has the advantages of high sensitivity and deep information in analyzing the light elements, it plays an important role in the study of helium behavior in materials. Helium embrittlement is one of the main reasons for the degradation of the Hastelloy N alloy, which has been considered as the promising candidate structural material for the further molten salt reactor. In this work, the profile of helium concentrationin sample of Hastelloy N alloy was analyzed by ERDA experiments applying grazing-incidence geometry. However, the result was limited within the depth range of 0~175 nm, and it shown that helium atoms escaped in the range from the irradiated surface of the sample to the depth of ~33 nm when annealing the sample at 800℃ The annealing at higher temperature (1 050℃) increased the escape of helium atoms, but a small fraction of helium atoms still trapped in the sample. In addition, the profile of helium concentration was obtained in the helium-irradiated pure nickel film in the depth range of 0~950 nm, using the ERDA experiments in transmission geometry. This indicates that the diffusion behavior of helium atoms in bulk samples can be completely obtained using the ERDA experiments in tranmission geometry if the bulk material can be prepared into a thin film sample.