2,2,2-三硝基乙基-N-硝基甲胺的热安全性

为评价2,2,2-三硝基乙基-N-硝基甲胺(TNMA)的热安全性, 得到计算TNMA热安全性参数用的基本数据, 用经验式估算了TNMA的比热容(C_p)和热导率(λ). 用键能贡献于生成热Q_f的加和法, 估算了TNMA的标准生成焓Δ_cH_m^θ(TNMA, s, 298.15 K). 用热力学公式计算了TNMA的标准燃烧焓ΔU_m^θ(TNMA, s, 298.15 K)和标准燃烧能Δ_cH_m^θ(TNMA, s, 298.15 K). 用Kamlet-Jacobs 公式估算了爆速、爆压和爆热. 用经验式估算了分解热(Q_d). 通过差示扫描量热(DSC)曲线和高灵敏度布鲁顿玻璃薄膜压力计测得的逸出气体标准体积(V_H)-时间(t)曲线, 得到了TNMA放热分解反应的动力学参数. 用上述基本数据得到了评价TNMA的热安全性参数: 自加速分解温度(T_SADT), 热爆炸临界温度(T_be0和T_bp0), 绝热至爆时间(t_TIad), 撞击感度50%落高(H₅₀), 热点起爆临界温度(T_cr), 被300 K环境包围的半厚和半径为1 m的无限大平板、无限长圆柱和球形TNMA的热感度概率密度函数S(T), 相应于S(T)-T关系曲线最大值的峰温(T_S(T)max), 安全度(SD), 临界热爆炸环境温度(T_acr)和热爆炸概率(P_TE). 结果表明: (1) TNMA有较好的热安全性和对热抵抗能力, 与环三亚甲基三硝胺(RDX)相比, TNMA易从热分解过渡到热爆炸; (2) 不同形状大药量TNMA 热安全性降低的次序为: 球>无限长圆柱>无限大平板; (3)TNMA有高的燃烧能、高的爆轰化学能(爆热)和接近环四亚甲基四硝胺(HMX)的爆炸性能, 其对冲击敏感, 冲击感度与季戊四醇四硝酸酯(PETN)和特屈尔接近, 可用作混合炸药主组分.     

酒石酸铅锆的制备、表征及其燃烧催化作用

以酒石酸、硝酸氧锆和硝酸铅为原料,合成出了双金属盐酒石酸铅锆,采用有机元素分析、X射线荧光光谱和FTIR对其进行了表征。在程序升温条件下,利用TG/DTG、DSC、固相原位反应池/FTIR联用技术,研究了酒石酸铅锆的热行为和热分解机理,描述了酒石酸铅锆的热分解过程,分析得出其最终分解产物为ZrO2、PbO和C。利用螺压工艺制备了含酒石酸铅锆的推进剂样品,研究了酒石酸铅锆对双基系推进剂燃烧性能的影响,分析了其燃烧催化作用。结果表明,酒石酸铅锆对双基系推进剂的燃烧具有良好的催化作用,是一种高效的燃烧催化剂;酒石酸铅锆热分解的最终产物PbO是催化燃烧的主要活性物质,推进剂燃烧过程中形成了氧化铅-铅循环催化体系,而锆和碳则起辅助催化的作用。     

超级铝热剂Al/CuO前驱体的制备、表征、热分解机理及非等温分解反应动力学

以硝酸铜、无水乙醇、1,2-环氧丙烷和纳米铝粉为原料, 在超声振荡条件下, 采用溶胶-凝胶法制备了纳米复合含能材料——超级铝热剂Al/CuO的前驱体. 利用热重-差示扫描量热-傅里叶变换红外-质谱(TG- DSC-FTIR-MS)联用技术, 研究了纳米Al/CuO溶胶-凝胶前驱体的热行为和分解过程及机理. 利用不同升温速率下的TG-DTG分析, 研究了纳米超级铝热剂Al/CuO的溶胶-凝胶前驱体的热分解反应机理, 采用了6种动力学分析方法进行动力学参数计算, 得到前驱体分解反应的表观活化能、反应级数、频率因子等动力学参数, 纳米Al/CuO前驱体分解反应的动力学方程为: dα/dt=10^14.0×4α^3/4exp(-2.0×10⁴/T).     

超级铝热剂的制备、表征及其燃烧催化作用

用纳米铝粉和纳米氧化铅、纳米氧化铜和纳米三氧化二铋为原料,采用超声分散复合的方法,制备了纳米超级铝热剂Al/PbO、Al/CuO和Al/Bi₂O₃。采用X射线粉末衍射(XRD)、扫描电镜及能谱分析(SEM-EDS)和红外光谱(IR)对原料和产物的物相、组成、形貌和结构进行分析表征;运用差示扫描量热仪(DSC)评估三种超级铝热剂与双基推进剂主要组分的相容性;研究了3种超级铝热剂对双基推进剂燃烧性能的影响。结果表明,Al/PbO、Al/CuO和Al/Bi₂O₃与推进剂主要组分硝化棉(NC)、硝化棉/硝化甘油(NC/NG)混合物和吉纳(DINA)的相容性均良好,而与黑索今(RDX)和1,3-二甲基-1,3-二苯基脲(C₂)相对较为敏感;含三种纳米超级铝热剂的双基推进剂表现出优异的燃烧性能。     

Thermal behavior of 1,2,3-triazole nitrate

The thermal decomposition behaviors of 1,2,3-triazole nitrate were studied using a Calvet Microcalorimeter at four different heating rates. Its apparent activation energy and pre-exponential factor of exothermic decomposition reaction are 133.77 kJ mol⁻¹ and 10^14.58 s⁻¹, respectively. The critical temperature of thermal explosion is 374.97 K. The entropy of activation (ΔS ^≠), the enthalpy of activation (ΔH ^≠), and the free energy of activation (ΔG ^≠) of the decomposition reaction are 23.88 J mol⁻¹ K⁻¹, 130.62 kJ mol⁻¹, and 121.55 kJ mol⁻¹, respectively. The self-accelerating decomposition temperature (T _SADT) is 368.65 K. The specific heat capacity was determined by a Micro-DSC method and a theoretical calculation method. Specific heat capacity equation is C_\textp ( \textJ mol ^{- 1} \text K ^{- 1} ) = - 42.6218 + 0.6807T C_{\text{p}} \left( {{\text{J mol}}^{ - 1} {\text{ K}}^{ - 1} } \right) = - 42.6218 + 0.6807T (283.1 K < T < 353.2 K). The adiabatic time-to-explosion is calculated to be a certain value between 98.82 and 100.00 s. The critical temperature of hot-spot initiation is 637.14 K, and the characteristic drop height of impact sensitivity (H ₅₀) is 9.16 cm.     

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.     

Almost periodic solutions of second-order neutral delay-differential equations with piecewise constant arguments

In this paper, we present an existence theorem of almost periodic solutions of second-order neutral delay-differential equations with piecewise constant arguments of the form (x(t)+x(t−1))″=qx([t])+f(t), where [·] denotes the greatest integer function, q is a nonzero constant, and f(t) is almost periodic.     

类钙钛矿化合物Ca(Mn2 Cu1)Mn4 O12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(Mn2 Cu1 )Mn4 O1 2 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 10 73K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 - 4 6 % .     

Hydrothermal Synthesis, Crystal Structure and Luminescent Properties of an Organically Templated 2-D Uranyl Sulfate

An organically templated 2-D uranyl sulfate, {（C2H8N）[（UO2）Cl（SO4）（H2O）] }n 1, has been hydrothermally synthesized. The crystal and molecular structures have been determined by X-ray crystallography method and spectral techniques. 1 belongs to monoclinic, space group P21/c with a = 8.3545（17）, b = 10.550（2）, c = 12.370（3）A, β = 102.64（3）°, V = 1063.9（4）A3, Mr = 464.64, De= 2.901 g/cm^3, F（000） = 836,μ = 15.710 mm^-1, Z= 4, the final R = 0.0286 and wR = 0.0685 for 10164 observed reflections with Ⅰ 〉 2σ（Ⅰ）. 1 presents a two-dimensional layer-like structure constructed from infinite anionic [（UO2）Cl（H2O）（SO4）]^- layers with [C2H8N]^＋ cations balancing the charge and a number of intermoleeular hydrogen bonds （C-H…O and O-H…Cl） existing in the solid state. The fluorescence properties of 1 have also been discussed.