含CL-20的改性双基推进剂的热行为及非等温反应动力学

用DSC和TG方法研究了含六硝基六氮杂异伍兹烷(CL-20)的改性双基推进剂在常压(0.1 MPa)和高压(4和7 MPa)下的热行为和高压下的热分解反应动力学. 结果表明, 该推进剂常压下DSC曲线有3个放热峰, 相应TG曲线有3个失重过程; 而高压下DSC曲线只有一个放热峰, 高压下放热峰的峰温随加热速率增大而升高. 高压下该推进剂放热分解反应机理和反应动力学参数受测试环境压强影响较弱, 反应机理是随机成核和随后生长, 放热分解反应的动力学方程可以表示为, 4 MPa时, dα/dt=1014.5(1-α)[-ln(1-α)]1/3e-17981.7/T; 7 MPa时, dα/dt=1014.7(1-α)·[-ln(1-α)]1/3e-18138.1/T.     

Quantification of testosterone and epitestosterone in biological samples by capillary electrophoresis with immunoaffinity extraction

Testosterone is one of the most common doping drugs abused by athletes. Therefore, it is necessary to develop a sensitive and simple method to monitor testosterone and its epimer epitestosterone. An off-line immunoaffinity extraction followed by capillary electrophoresis for simultaneous determination of testosterone and epitestosterone has been described in this paper. Anti-epitestosterone monoclonal antibody which is specific to both testosterone and epitestosterone had been prepared and immobilized on a Sepharose 4B stationary phase. The immunoaffinity column was used for sample cleanup, extraction and preconcentration. After elution and reconstitution, testosterone and epitestosterone in the sample were separated and quantified by micellar electrokinetic chromatography(MEKC) using the borate buffer (200 mM borate, pH 8.7) containing 40 mM sodium cholate as a chiral selector. The immunoaffinity column was evaluated in different parameters such as the retention mechanism, selectivity, binding capacity, elution protocol, and reusability. The separation of these two compounds by MEKC was also optimized. Limit of detection for testosterone and epitestosterone were 5 and 23 ng mL⁻¹, respectively. It was satisfactory to apply this method to analyze testosterone and epitestosterone in spiked urine sample with the recoveries from 78% to 109%.     

社会群体中观点的信任、演化与共识

针对连续观点动力学模型中缺乏对个体信任及其观点的不同权重的考虑,本文通过扩展HegselmannKrause模型,引入个体间的信任度和观点间的相似度,将有限信任假设扩展为有限影响假设,建立带权重的观点更新模型,以研究社会群体中少数的偏执个体和权威个体对观点形成、演化以及共识构建过程的影响.仿真结果表明,这两类个体的初始观点尽量接近观点分布区间中点0.5或者增加偏执个体的影响阈值和权威个体的可信任程度可以使群体形成更少和更大的观点簇.随着偏执个体的影响阈值增加,最大簇的观点位置集中于0.5附近;而增加权威个体的可信任程度,最大簇的观点不断接近权威个体的最终观点.模型结果能够在一定程度上反映和解释现实社会中偏执个体和权威个体现象.     

纳米Ag/CNTs复合材料的制备、表征及对环三亚甲基三硝胺热分解的影响

采用银镜法和水热法制备了两种纳米Ag/CNTs(碳纳米管)复合材料, 利用傅里叶变换红外(FTIR)光谱、粉末X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜及能量散射光谱仪(SEM-EDS)对复合物的物相、组成、形貌和结构进行分析表征, 并运用差示扫描量热法(DSC)研究了纳米Ag/CNTs 复合材料对环三亚甲基三硝胺(RDX)热分解特性的影响. 结果表明: 纳米Ag 以10-80 nm的不规则球形“粘附”于纳米CNTs 表面,分散较均匀, 水热法制得的复合物表面纳米Ag较大、且负载的Ag粒子较多; 纳米Ag/CNTs 复合材料的加入改变了RDX的热分解过程, 使原有占主导的液相分解变为二次的气相反应加剧, RDX主分解峰形发生了明显的改变; 纳米Ag/CNTs 复合材料对RDX热分解的催化主要表现为分解温度的降低.     

Density Functional Theory Studies on the Adsorption of NH2NO2 on Al13 Cluster

Density functional theory method with full geometry optimization was used to study the adsorption of nitroamine (NH₂NO₂) on Al₁₃ cluster. Both dissociative and nondissociative adsorption structures were predicted with different NH₂NO₂ molecule orientations on Al₁₃ cluster surfaces. In dissociative chemisorption, the main decomposition products of NH₂NO₂ are O atom(s) and NH₂NO or NH₂N species. The O atoms being ruptured from the N?CO bond form strong Al?CO bonds with the neighboring Al around the adsorbed sites. In addition, the species obtained as a result of O atom elimination remains bonded to the surface. The largest adsorption energy is ?737.66?kJ/mol when the NH₂NO₂ molecule decomposes into two O atoms and a NH₂N fragment. For nondissociative adsorption, the seriously deformed nitroamine forms various N?CO?CAl bonding configurations with Al. The significant charge transfer occurs for all adsorption configurations. The most charge transfer is 2.068 e from the Al cluster surface to the fragments of the decomposed NH₂NO₂. The change of the electronic structures is obvious due to the adsorption or dissociation of NH₂NO₂ molecule. Nitroamine readily oxidizes the aluminum surface of the Al₁₃ cluster.     

类钙钛矿化合物Ca（Mn2Cu1）Mn4O12的磁性与磁电阻效应

利用固相反应法制备了名义成分为Ca(Mn2Cu1)Mn4O12的类钙钛矿锰氧化物.x射线衍射表明，为了获得较为致密的样品和减小杂相含量，可以采用高温烧结再在1073K长时间空气中退火的制备方法.样品在低温下同时存在铁磁相和反铁磁相，由于反铁磁相的存在导致样品在4.5K时的磁化强度显著降低，并在8T的高磁场下仍未达到饱和.样品呈半导体导电性质，在85K和6T磁场下磁电阻比的最大值可达-46%. 关键词： ［AC3］(B4)O12类钙钛矿锰氧化物 庞磁电阻效应 铁磁性 反铁磁性     

Synthesis, Crystal Structure and Luminescent Property of a Novel 1-D Cadmium(Ⅱ) Complex: [Cd2(C8H3NO6)2(H2O)4]n·2nH2O

A novel one-dimensional chain-like coordination polymer constructed from 3-nitrobenzene-1,2-dicarboxylic acid, [Cd2(C8H3NO6)2(H2O)4]n·2nH2O, has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to monoclinic, space group P21/c with a = 6.1252(8), b = 20.706(3), c = 8.8067(11) (A), β = 95.608(2)°, V= 1111.6(2)(A)3, Mr =751.12, Dc = 2.244 g/cm3, F(000) = 736, μ = 2.011 mm-1, Z = 2, the final R = 0.0262 and wR = 0.0692for 2338 observed reflections with I ＞ 2σ(I). The structure of the title compound presents a 1-D chain-like structure constructed by dimer units, [Cd2(CsH3NO6)2(H2O)4]n, through two carboxylate oxygen atoms. The fluorescence of the tifle compound has been also discussed in this paper.     

纳米复合氧化物CuO·SnO2的制备与结构表征

0引言由于纳米材料在热学、电学、磁学、光学等方面具有的独特性能,使其在新功能材料、催化、光电能转换等许多领域引起了人们浓厚的研究兴趣[1]。近年来,纳米催化剂对固体推进剂的燃烧性能影响研究已成为热点[2～9]。但是由于固体推进剂燃烧的特殊性,要求不仅提高燃速,而且降低压力指数,因此并非所有的纳米催化剂都是有效的。大量实践已证明[10],多种催化剂的复合使用,将可获得远远优于单一催化剂的效果。研究已发现[11],纳米复合氧化物是由多种元素复合而成,使其在结构和性能上得到互补和叠加,加上纳米粒子所具有的各种效应,从而产生独特…     

In situ Alkylation of 4,4'-Bipyridine in Hydrothermal Synthesis of an Iodoplumbate Inorganic-organic Hybrid with Fluorescence

A novel 1-D iodoplumbate hybrid,2(Pb3I9)3-·3(C14H18N2)2+ 1,has been hydrothermally synthesized and characterized by IR spectra,TGA and single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group P21/c,with a=12.057(2),b=14.024(3),c=24.742(5) ,β=90.48(3)°,V=4183.6(14)3,Z=4,R=0.0477 and wR=0.0800.The title compound consists of 1-D chains(Pb3I9)n3n-parallel to the [100] direction and stacks of alkylated 4,4'-bipyridium cations running along the [011] direction.Each anionic chain is surrounded by six arrays of alkylated 4,4'-bipyridium cations through extensive C-H…I atypical hydrogen-bonding interactions to afford an interesting 3-D supramolecular network.Significant fluorescent property of the compound was observed at room temperature.