金属—橡胶硫化粘接复合体剥离破坏行为的研究

本文分析了对橡胶分子链特性、部分交联弹性聚合物材料的粘弹行为及金属──橡胶硫化粘接体剥离过程中聚合物分子链的应力分布状况和剥离破坏模型，认为粘着一滑动（Stick—slip）模型剥离破坏并非是橡胶类材料的固有特征，而是由于金属──橡胶硫化粘接过程中的分子取向交联和部分交联弹性材料多个凯尔文（Kelvin）模型粘弹行为的综合结果．同时指出单从剥离试验的结果难以表征金属——橡胶硫化粘接复合作的粘接效果．     

基于Pro/E双分型面模具的3D总装配设计

详细介绍了利用Pro／E软件在双分型面模具设计应用中的一般流程，并结合具体实例说明了模具设计及3D总装配设计的具体步骤。采用这种方法，不但可进行造型设计和快速精确地生成模具的型腔和型芯，还可实现模具的3D总装配设计，有利于缩短模具的设计周期；并可利用Pro／E提供的开模仿真功能，及时发现模具设计中的错误，有效避免了工人的反复劳动。     

超微细改性Al(OH)3填充LDPE/EVA的研究

Al(OH）3是LDPE／EVA主要的阻燃，消烟填充剂。研究了不同粒度，表面处理及填充量的Al(OH）3对LDPE／EVA的氧指数（OI），烟密度等级（SDR）和物理机械性能的影响。     

Thermal analysis of montmorillonites modified with quaternary phosphonium and ammonium surfactants

The thermal stability of seven organically modified montmorillonites (‘organoclays’) has been investigated using differential thermal analysis, differential scanning calorimetry, and thermogravimetry in conjunction with X-ray diffractometry. Six organoclays were synthesised by replacing the interlayer inorganic cations, initially present, with quaternary phosphonium and ammonium surfactant cations. The samples modified with tetrabutylphosphonium (TBP), and butyltriphenylphosphonium (BTPP) ions have an appreciably higher thermal stability than the octadecyltrimethylammonium (ODTMA)-modified clays. Thus, in the case of TBP- and BTPP-modified montmorillonites, the onset temperature of decomposition is close to 300 °C. Samples modified with hexadecyltributylphosphonium (HDTBP) ions have a lower onset temperature of decomposition of 225 °C. In comparison, the onset temperature for ODTMA-montmorillonites (obtained at different concentrations of ODTMA-bromide) ranges from 158 to 222 °C, being highest where the concentration of intercalated surfactant is lowest. The onset temperature for a commercial alkylsilane-treated quaternary ammonium-modified organoclay (S-BEN N-400FP) is 207 °C. The basal spacing of the TBP- and BTPP-modified clays is 1.7–1.8 nm, indicating a monolayer arrangement of quaternary phosphonium ions in the interlayer space, while the value of 2.5 nm for HDTBP-montmorillonite indicates a more open structure. The ODTMA-modified samples have basal spacings ranging from 1.9 to 2.1 nm, indicative of a bilayer to pseudo-trilayer arrangement. The exceptionally high basal spacing of 3.4 nm for the S-BEN N-400FP organoclay might be due to interlayer penetration of organosilane hydrolysis products during synthesis. The thermal properties of organoclays are apparently related to the nature of the surfactants and their arrangement in the interlayer space of montmorillonite.     

Ion-dipole interactions between adsorbed CO and support cations in Pt/K-LTL

The adsorption of carbon monoxide on a non-acidic Pt/K-LTL catalyst has been studied by diffuse reflectance and transmission IR spectroscopy. The CO spectrum is strongly dependent on the experimental conditions. Adsorption on the small Pt clusters in the presence of water gives linear-CO bands between 2060 and 1990 cm^–1 and a bridging-CO band around 1800 cm^–1. In the absence of water, the linear bands are red shifted to about 1940 and 1720 cm^–1, respectively. The frequency shift is attributed to an ion-dipole interaction between adsorbed CO and support cations. The ion-dipole interaction is screened by the adsorbed water leading to a smaller red shift in the CO stretching frequency.     

NETEM阅读部分的真实性分析

从真实性的角度出发,利用Bachman的任务特征框架分析了NETEM阅读理解部分对考生交际语言能力的测试.分析表明,NETEM在输入材料方面有较高的真实性,任务涉及的语言能力的真实性也有很大的提高.但从输入与回答之间的关系看,个别题目未能体现交际语言能力的特点,仍有待改进.     

C5/C9共聚石油树脂的加氢工艺研究

为了得到优质的加氢石油树脂,采用固定床加氢反应装置对C5/C9共聚石油树脂进行了加氢研究。原料为色相（Fe-Co比色法）11#、软化点122℃的C5/C9共聚石油树脂,采用镍基催化剂,反应温度：230-260℃,反应压力：2.0-4.0 MPa,空速：0.5 h-1,氢油体积比：600∶1,制备出色相1#,软化点98℃的水白色加氢石油树脂,考察了加氢过程中各种工艺条件的影响。     

发电系统短期可靠性评估的等效机组法

本文提出了等效机组的概念,有效地解决了发电系统短期可靠性评估中的“状态爆炸”难题该方法不仅提高了短期可靠性评估的速度和精度,而且极大地压缩了计算存贮量,使发电系统短期可靠性评估更趋于实用化.通过对示例发电系统进行短期可靠性评估,其结果证明了该方法的正确性和有效性.     

Fluorescence of poly(di-n-alkylsilane)s in room-temperature solution

A comprehensive study of the electronic absorption and emission spectra and the fluorescence quantum yield and lifetime of seven poly(di-n-alkylsilane)s and of three isotopically labelled poly(di-n-hexylsilane)s in hydrocarbon solution at room temperature is reported. Also reported are fluorescence polarization and carbon tetrachloride quenching of fluorescence of poly(di-n-hexylsilane). The observed fluorescence spectra, quantum yield, and polarization depend on the selected excitation energy in a very characteristic fashion, whereas the fluorescence lifetime does not; however, it depends on the selected emission energy. These characteristic dependencies are qualitatively accounted for by the previously proposed segment distribution model if one assumes that the photophysical behavior at higher excitation energies is strongly affected by the presence of a low-lying weakly allowed state in short-segment chromophores and the behavior at lower excitation energies is dictated by the selective excitation of emitting long-segment chromophores.     

An EXAFS study of the Mo/TiO2 hydrodesulphurization catalysis

In-situ EXAFS studies of sulphided Mo/TiO₂ catalysts have shown that at low Mo loadings (2–4 wt%), an active species with a short Mo-S distance of 2.25 Å is formed, while on Mo/TiO₂ with high Mo loadings as well as on Mo/-Al₂O₃, bulk MoS₂ (Mo-S, 2.42 Å) is formed. The species with the short Mo-S distance has Mo in an oxidation state close to 6 + and is likely to result from the sulphidation of the tetrahedral molybdate species present in the oxidic precursor at low Mo loadings. The calcination temperature of the oxidic precursor appears crucial, a high calcination temperature of 973 K favouring the formation of MoS₃ on sulphidation, and a low calcination temperature of 623 K favouring MoS₂.Contribution No. 790 from the Solid State and Structural Chemistry Unit.