Optimal control of molecular motion: design, implementation, and inversion

This paper reviews recent theoretical and experimental developments aimed at controlling molecular motion using tailored laser fields. Emphasis is given to seeking optimal designs for the laser controls and optimal implementation of the controls in the laboratory. Optimization on both counts provides a rigorous, flexible, and physically attractive means for obtaining the best possible control over molecular motion under any specified conditions. The theoretical design and laboratory implementation of control are best effected by a closed-loop process that draws on observations of the evolving molecular sample to steer it toward the desired target. Going beyond control, similar closed-loop laboratory learning concepts may lead to automated molecular monitors for inversion to systematically identify details of molecular Hamiltonians.     

硫化胶制样技术对红外光谱分析的影响

样品粒径对硫化胶网络主链α－亚甲基浓度影响较大，但对侧甲基浓度影响甚微。样品粒径减小会导致样品严重氧化，因此压片法红外光谱分析要严格控制样品粒径。样品浓度对分析结果也有较大影响。在样品粒径小于２μｍ、样品与溴化钾质量比为（１～５）：１０００时，可获得较为理想的红外光谱图。     

Catalytic cracking of 1-butene to propene and ethene on MCM-22 zeolite

Catalytic cracking of butene to propene and ethene was investigated over HMCM-22 zeolite. The performance of HMCM-22 zeolite was markedly influenced by time-on-stream (TOS) and reaction conditions. A rapid deactivation during the first 1 h reaction, followed by a quasi-plateau in activity, was observed in the process along with significant changes in product distributions, which can be attributed to the fast coking process occurring in the large supercages of MCM-22.

Properly selected reaction conditions can suppress the secondary reactions and enhance the production of propene and ethene. According to the product distribution under different butene conversion, we propose a simple reaction pathway for forming the propene, ethene and by-products from butene cracking.

HMCM-22 exhibited similar product distribution with the mostly used high silica ZSM-5 zeolite under the same conversion levels. High selectivities of propene and ethene were obtained, indicating that the 10-member ring of MCM-22 zeolite played the dominant role after 1 h of TOS. However, MCM-22 exhibited lower activity and stability than that on high silica ZSM-5 zeolite with longer time-on-stream.     

林可霉素生产废水处理站的改造

对某林可霉素生产废水处理站进行了改造.为提高废水的可生化性,增设了水解调节池,好氧生化工艺改为AB法;对于废水中难于生物降解的有机物,采用Fenton氧化法处理,药剂投加量以出水水质达标为目标.处理站改造的工程投资为96.0万元,改造后的运行成本为3.36元/m3.     

Consolidation of Nano-Sized TiN Powders by Spark Plasma Sintering

Nano-sized TiN powders with an average particle size of 19 nm were synthesized via a new method, reduction–nitridation reaction in liquid ammonia. A consolidation procedure using spark plasma sintering (SPS) was used, and a dense TiN ceramic (>98% of theoretical) with mean grain size of 100–150 nm was obtained at 1380°C. The influence of sintering temperature on grain growth and microstructural evolution was also discussed.     

Carbon-encapsulated Fe nanoparticles from detonation-induced pyrolysis of ferrocene

Carbon-encapsulated Fe nanoparticles with size between 5 and 20 nm were synthesized via a picric acid-detonation-induced pyrolysis of ferrocene, which is characterized by a self-heating and extremely fast process. The nanoparticles exhibit well-constructed core-shell structures, with bcc-Fe cores and graphitic shells. The graphitic shells can protect effectively the cores against the attack of HNO₃ solution. The formation of the core-shell nanoparticles can be selectively controlled by adjusting the composition of the picric acid-ferrocene mixture, which determines C/Fe atomic ratio of the reaction system. The core-shell nanoparticles are preferably formed at low C/Fe atomic ratios, while tubular structures are formed at high C/Fe ratio. The possible pathway for the carbon-encapsulated Fe nanoparticles formation is discussed briefly.     

Synthesis of polystyrene end-capped with pyrene via reversible addition-fragmentation chain transfer polymerization

A novel benzodithioate compound with a pyrene structure in the R group, pyrenylmethyl benzodithioate (PMB) was synthesized. Using PMB as the chain transfer agent (CTA), the RAFT polymerizations of styrene with AIBN as an initiator were carried out in different reaction conditions. The results indicated that PMB was an effective CTA for the RAFT polymerizations of styrene with the “living”/controlled characteristics. The structures of the obtained polymers were characterized by ¹H NMR. The results showed that majority of the polymer chains contained the pyrene moiety in the chain end. The enhanced fluorescence property in CHCl₃ solution was observed. The chain-extension experiments of the obtained polystyrene (PS) with the monomers of styrene and methyl acrylate were successfully carried out.     

雷达吸波材料的研究现状及发展前景

首先阐述了吸波材料的研究意义,然后综合讨论了吸波材料的工作原理、类型以及研究现状, 最后介绍了吸波材料在军事方面的应用及未来的发展趋势。     

合成二氧化硅对硅橡胶性能的影响

介绍了合成二氧化硅及硅橡胶的结构性质，探究了二氧化硅的结构性质对硅橡胶补强性能的影响，指出了二氧化硅颗粒的大小、形态、聚结状态、表面性质和与高分子硅氧烷之间的相互作用是影响二氧化硅对硅橡胶补强性能的最主要的因素，并用实验对硅橡胶的硬度、拉伸强度、300％定伸应力、扯断伸长率、撕裂强度、压缩永久变形等物理性能进行测定，结果表明：BET比表面积180～200m^2／g，孔隙度（吸油量）为3.0～3.2mL／g，平均粒径为8～10岬的沉淀法白炭黑对硅橡胶具有很好的补强效果。