两个四阶微分算子积的自伴性

本文研究由微分算式D^4-DpD q生成的两个四阶微分算子Li(i=1，2)的积L2L1的自伴性，并在常型和奇型情形下，分别获得了两个四阶微分算子积自伴的充要条件．同时证明了若L1和L2自伴，则L=L2L1自伴的充要条件是L1=L2．     

多时段EOQ存贮问题一种策略的改进优化方法

本文对多时段费用变动型存贮问题的一种策略提出了改进优化方法.理论分 析和实证比较表明:改进方法较原方法不但费用更低,而且算法简便直观,适用性强.     

图的联结数与分数κ-消去图

设G是一个图,若对于图G的任一条边e,G-e都存在一个分数k-因子,则称G是一个分数k-消去图.若k=2,则称分数k-消去图为分数2-消去图.本文证明了当bind（G）≥2,并且δ（G）≥3时,G是分数2-消去图.     

油气吸附分离过程的研究

本文以油气回收的吸附剂筛选为出发点。研究了93号汽油在不同系列吸附剂上的吸附、脱附性能,以及活性炭微孔结构对吸附性能的影响,并与美国类似吸附剂作了比较。结果表明：所用吸附剂的吸附容量自欺欺人优于一般市售活性炭,可望应用于国内炼油厂,加油站和油田的油气吸附回收利用。     

基于长周期光纤光栅折射率敏感特性的混凝土结构钢筋锈蚀监测

研究了长周期光纤光栅(LPFG)谐振透射光谱对外界环境折射率变化的敏感特性,在此基础上提出了将混凝土内部钢筋周围环境折射率与LPFG光谱特性相结合的理论,设计了一种基于折射率测量的LPFG钢筋锈蚀监测传感器.采用LPFG透射光谱枪测技术,获取钢筋锈蚀过程中混凝土内部不同折射率环境所对应的LPFG透射光谱曲线族,进而得到...     

一类带p-Laplace算子的高阶Rayleigh型泛函微分方程周期解存在性问题

利用Mawhin拓展定理研究了一类带p-Laplace算子的非线性项前系数可变号的高阶Rayleigh型泛函微分方程(φ_p(y^（m）（t）))+f（y’（t））+β（t）g（y（t-τ（t）））=e（t）周期解存在性问题,与已有工作不同的是此中允许非线性项前的系数可变号,引进有别于以往工作的一点估计的方法获得周期解先验界,故估计先验界的方法和所获得的结果是新的.     

SYNTHESIS,CHARACTERIZATION AND QUENCHING BEHAVIOR OF A CATIONIC POLY(p-PHENYLENEVINYLENE) RELATED COPOLYMER

A cationic poly(p-phenylene vinylene) related copolymer without bulky phenylene substitutents attached to the conjugated backbone was prepared through Wittig reaction.The molecular structure and optical properties were highly investigated through ~1H-NMR,UV and PL spectroscopy.The quenching behavior was also investigated,and the results demonstrate that incomplete quenching exists,which is consistent with the cationic poly(p-phenylene vinylene) related copolymer containing bulky phenylene substitutents,p...     

Synthesis and antiviral activity of 4H-[1,2,5]oxadiazolo-[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides

A series of 4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides was designed,synthesized and evaluated against vesicular stomatitis virus(VSV)in Wish cell.The antiviral activities of all compounds were stronger than those of acyclovir,while their toxicities were similar to those of acyclovir.     

An ion-imprinted polymer supported by attapulgite with a chitosan incorporated sol-gel process for selective separation of Ce(Ⅲ)

The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the synthesis of a new attapulgitesupported polymer for selective separation of Ce(Ⅲ) from aqueous solution.The imprinting mechanism of prepared ion-imprinted polymer were discussed with the Characteristics of FT-IR and SEM.Results from the experiments of adsorption capacity and selectivity suggested that ion-imprinted polymer offered a fast kinetics for the adsorption of Ce(Ⅲ) under the optimum conditions. Its m...     

超声波作用下NaBH~4-PEG400-THF体系对酯的还原

本文报道了利用超声波照射可以促进NaBH~4-PEG400-THF体系对酯的还原。与用NaBH~4-PEG400体系还原酯的方法相比具有反应速度快,反应条件温和以及产物产率较高的优点,但分子内的硝基和双键不被还原,选择性较好。