甘油—乙醇混合液超声性质研究

测量了不同浓度的甘油、乙醇混合液的声速和密度,计算了超额绝热压缩系数.结果表明,在整个浓度范围内,甘油和乙醇之间存在着强烈的分子相互作用.     

随机参数Duffing系统中的随机混沌及其延迟反馈控制

研究了谐和激励下含有界随机参数Duffing系统(简称随机Duffing系统)中的随机混沌及其延迟反馈控制问题.借助Gegenbauer多项式逼近理论，将随机Duffing系统转化为与其等效的确定性非线性系统.这样，随机Duffing系统在谐和激励下的混沌响应及其控制问题就可借等效的确定性非线性系统来研究.分析阐明了随机混沌的主要特点，并采用Wolf算法计算等效确定性非线性系统的最大Lyapunov指数，以判别随机Duffing系统的动力学行为.数值计算表明，恰当选取不同的反馈强度和延迟时间，可分别达到抑制或诱发系统混沌的目的，说明延迟反馈技术对随机混沌控制也是十分有效的. 关键词： 随机Duffing系统 延迟反馈控制 随机混沌 Gegenbauer多项式     

Expression and Characterization of HGV E2 cDNA in Pichia pastoris

A 559 base pair fragment of cDNA locating at the putative E2 region of GBV-C/HGV was in-serted into Pichia pastoris expression vector pPICgK in the reading frame of α-factor secreting signal pep-tide. The recombinant expression plasmid pPIC9K-E2 was introduced into P. pastoris GSll5 with electro-poration and recombined with the host genome by homological recombination. The His+Mut+ recombinantyeasts were selected and cultivated in the BMMY medium. After 3 days induction with 0. 5% methanol,the target protein(E2) accumulated up to 30% of total proteins in the supernatant. The expressed E2 pro-tein was proved possessing antigenicity and high specificity with Western blot and ELISA probed with serafrom the immunized rabbits and the patients infected by GBV-C/HGV.     

南京市城市绿地规模与经济发展水平关系分析

城市绿地是城市生态环境的重要组成因子之一．发展城市绿地，不仅可为城市居民创造良好的生存环境，而且通过改善城市人居环境，促进旅游业和服务业的发展，以及创造更好的外商投资环境，将间接地对城市经济的发展产生显著的促进作用．以南京市为研究对象，采用回归分析方法，分析南京市城市绿地规模与城市经济发展水平之间的定量关系，结果表明二者之间有显著相关性．此外，还建立了南京市城市经济增长与各驱动因子之间的多元线性回归模型，并据此模型对南京市2003～2010年城市经济增长对人均公共绿地面积的需求做了初步预测，发现2010年的预测值与南京市编制的城市绿地规划所规定的该年人均公共绿地面积较为接近，表明本研究的方法和成果具有较好的可靠性．     

The Lagrangian Globalization Method for Nonsmooth Constrained Equations

The difficulty suffered in optimization-based algorithms for the solution of nonlinear equations lies in that the traditional methods for solving the optimization problem have been mainly concerned with finding a stationary point or a local minimizer of the underlying optimization problem, which is not necessarily a solution of the equations. One method to overcome this difficulty is the Lagrangian globalization (LG for simplicity) method. This paper extends the LG method to nonsmooth equations with bound constraints. The absolute system of equations is introduced. A so-called Projected Generalized-Gradient Direction (PGGD) is constructed and proved to be a descent direction of the reformulated nonsmooth optimization problem. This projected approach keeps the feasibility of the iterates. The convergence of the new algorithm is established by specializing the PGGD. Numerical tests are given. This author's work was done when she was visiting The Hong Kong Polytechnic University. His work is also supported by the Research Grant Council of Hong Kong.     

1．5GHz锯材超导腔的研制

介绍铌材超导腔的研制进展，重点讨论了国产铌腔的材料改性，以及相应的超导腔性能的改进．叙述了１．５ＧＨｚ铌腔的腔形设计，分析了铌材的射频性能和机械性能，制定了铌腔制作与后处理的特定工艺．最后给出了１．５ＧＨｚ铌材超导腔的低温实验结果．     

The study of the partitioning mechanism of methyl orange in an aqueous two-phase system

An aqueous two-phase system of dodecyl triethylammonium bromide (C₁₂NE, cationic surfactant) and sodium dodecyl sulfate (SDS, anionic surfactant) mixture is proposed for the extraction of some dyes and porphyrin compounds. Transparent two phase-systems are formed when the surfactant concentrations and C₁₂NE/SDS ratios are in certain regions. In this study, the aqueous two phase-systems were prepared by mixing 0.1 mol l⁻¹ C₁₂NE and SDS with a molar ratio of 1.7:1.0. The results showed that negatively charged chlorophyll (sodium copper chlorophyllin) and positively charged dye (methyl violet) were efficiently extracted into the upper phase. The negatively charged methyl orange (pH>7) was moved into the upper phase mostly while amphoteric methyl orange (pH<3) was distributed in the two phases uniformly. Except for hydrophobic force, charge interaction between solute and surfactant also play an important role in the extraction process.