空间结构热-动力学耦合系统稳定性的有限元分析

针对在轨航天器柔性附件的热-动力学耦合系统,提出了一种稳定性分析有限元方法。该系统的状态方程既包括考虑辐射换热且耦合了结构变形的非线性瞬态热传导方程,也包括与瞬态温度场相联系的结构动力学方程。由于结构变形对于受热条件的耦合影响以及辐射换热的存在,该系统具有高度非线性。借助于非线性振动理论,给出了系统热诱发振动的稳定性准则。针对不同的结构,可以计算出不同的运动稳定边界,该边界将参数空间分成了稳定区域和不稳定区域。对哈勃太空望远镜太阳帆板进行了稳定性分析,该方法所得数值解与文献结果一致。对更为复杂的卫星天线,用该方法给出其发生热颤振的参数条件,探讨了结构参数、加热条件对其热-动力学耦合系统稳定性的影响。     

Inhibitory Kinetics of p-Substituted Benzaldehydes on Polyphenol Oxidase from the Fifth Instar of Pieris Rapae L.

Polyphenol oxidase (PPO) is the enzyme responsible for enzymatic browning during the growth of insects. It is also involved in defense reactions and is related with immunities in insects. PPO, a metalloenzyme oxidase, catalyzes the oxidation of ο-diphenol to ο-quinone. The present paper de- scribes the effects of benzaldehyde and its p-substituted derivatives on the activity of PPO from the fifth instar of Pieris rapae L. PPO from the fifth instar of Pieris rapae L. was purified using ammonium sulfate fractionation and chromatography on Sephadex G-100. The enzyme kinetics was characterized using L-3,4-dihydroxyphenylalanine (L-DOPA) as substrate. The results show that benzaldehyde, p- hydroxybenzaldehyde, p-chlorobenzaldehyde, and p-cyanobenzaldehyde can inhibit the PPO activity for the oxidation of L-DOPA. The inhibitor concentration leading to 50% activity lost, IC50, was esti- mated to be 5.90, 5.62, 2.83, and 2.91 mmol/L for the four tested inhibitors, respectively. Kinetic analy- ses show that the inhibitory effects of these compounds are reversible. Benzaldehyde, p- hydroxybenzaldehyde, and p-chlorobenzaldehyde are noncompetitive inhibitors while p-cyano- benzaldehyde is a mixed-type inhibitor. The inhibition constants were determined for all four inhibitors. p-chlorobenzaldehyde and p-cyanobenzaldehyde were more potent inhibitors than the other com- pounds. These results provide a basis for developing PPO inhibition-based pesticides.     

Memory Efficient String Matching Algorithm for Network Intrusion Management System

As the core algorithm and the most time consuming part of almost every modern network intrusion management system (NIMS), string matching is essential for the inspection of network flows at the line speed. This paper presents a memory and time efficient string matching algorithm specifically designed for NIMS on commodity processors. Modifications of the Aho-Corasick (AC) algorithm based on the distribution characteristics of NIMS patterns drastically reduce the memory usage without sacrificing speed in software implementations. In tests on the Snort pattern set and traces that represent typical NIMS workloads, the Snort performance was enhanced 1.48%-20% compared to other well-known alternatives with an automaton size reduction of 4.86-6.11 compared to the standard AC implementation. The results show that special characteristics of the NIMS can be used into a very effective method to optimize the algorithm design.     

HCV全基因组培养细胞的比较蛋白组学研究

利用比较蛋白质组技术研究了转染丙型肝炎病毒(Hepatitis C virus, HCV)全基因组的人肝癌细胞系Huh7细胞模型中蛋白质表达谱的变化, 建立了Huh7-HCV的双向凝胶电泳蛋白质表达图谱和数据库. 通过双向凝胶电泳分离和图像分析, 对表达差异2倍以上蛋白质点进行了胶内酶解和MALDI-TOF MS鉴定. 得到包括与细胞骨架蛋白、细胞周期、凋亡和信号转导等相关的14个蛋白质, 并且用Western blot验证了热休克蛋白70的蛋白质组研究结果. 利用HCV全基因组培养系统, 采用蛋白质组学技术, 为研究HCV病毒和宿主细胞相互作用提供了新的实验数据, 为深入研究HCV病毒复制和分子致病机理奠定了基础.     

论当代量子引力的空间时间观念

首先讨论当代诸种量子引力,如超弦/M理论、圈量子引力等,继而研究空间时间量子涨落对量子引力理论的经验检验,最后讨论了有关量子引力时空的物理实在问题.     

四元数矩阵M-P逆变换的Jacobi行列式

应用奇异四元数矩阵的奇异值分解,给出了奇异四元数矩阵的外微分式,并由此得出了M-P广义逆变换的Jacobi行列式.本文所得到的结果在求奇异四元数矩阵正态分布及Wishart分布的密度函数表达式中发挥重要作用.     

Synthesis and Crystal Structure of 5-（p-Toly1）-4- [2-（2,4-dichlorophenoxy）acetamido]-l,2,4- triazole-3-thione Ethyl Acetate Solvate

A novel compound 5-（p-tolyl）-4-[2-（2,4-dichlorophenoxy）acetamido]-1,2,4-tria zole- 3-thione 2a has been synthesized by the reaction of 5-（p-tolyl）-4-amino-1,2,4-triazole-3-thione 1 with 2-（2,4-dich/orophenoxy）acetyl ch/oride. Interestingly, the title compound 2 was obtained when 2a crystallizes from a mixed solution of petroleum ether and ethyl acetate, and it has been characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 9.780（5）, b = 10.876（6）, c = 11.615（6） /A, a = 104.822（7）, β= 94.105（6）, ）, = 94.305（6）°, V= 1185.7（11）/A3, Z = 2,μ = 0.397 mm^-1, Mr= 497.39, Dx= 1.393 g/cm^3, F（000） = 516, S = 1.097, the final R = 0.0730 and wR = 0.2133 for 4111 unique reflections （Rint = 0.0525） with 3212 observed ones. The dihedral angles made by the triazole ring with the methyl- and chloro-substituted benzene rings are 43.5（7） and 50.2（9）°, respectively. Some intra- and intermolecular hydrogen bonds together with C-H…π interactions existing in the lattice stabilize the crystal structure.     

铁路道砟形态特征的统计分析与几何重构

道砟颗粒几何形态特征对其力学特性影响显著。为了量化研究铁路道砟形态特征,以真实的铁路一级碎石道砟颗粒为例,采用3D激光扫描获取道砟颗粒点云数据,引入道砟整体形态特征指标(长轴、中轴、短轴、球度指数),提出道砟局部形态特征指标(曲率指数),统计并建立上述整体和局部形态特征指标的概率密度分布函数。在此基础上,基于本征正交分解(POD)及径向基(RBF)神经网络提出了基于颗粒形态指标概率密度分布的道砟样本的重生成算法,重构道砟颗粒样本库。采用上述重生成算法分别重构了600及4 000个颗粒道砟,结果表明:重构道砟样本形态特征指标的统计分布结果均与真实扫描试样结果接近,证明该方法能够快速实现基于颗粒形态指标概率密度分布的任意数量道砟样本的建立。     

关于线性多目标规划一种新方法的注记

指出了文"求解线性多目标规划的一种新方法"中有关线性多目标规划弱有效解的判别准则与算法的一些缺陷和错误,并提出了补充和修改意见.     

基于萘普生-芳基金属配合物的抗癌及抗炎性能

以萘普生(NPX)为前体,分别与芳基钌(Ru)、锇(Os)及铱(Ir)二聚体反应制备了3个单核配合物[Ru(η⁶-p-cymene)(NPX-bpy) Cl]Cl (1),[Os (η⁶-p-cymene)(NPX-bpy) Cl]Cl (2)和[Ir(η⁵-Cp^*)·(NPX-bpy) Cl]Cl(3)。利用元素分析、电喷雾质谱和核磁共振波谱对3个配合物的组成和结构进行了表征,并研究了其细胞毒性。结果表明,3个配合物对几种肿瘤细胞株均无毒性(IC₅₀>100μmol/L),仅配合物1对NB-4细胞有中等程度的毒性(IC₅₀=45. 2μmol/L),且毒性大于配合物2和3,这可能与配合物1在细胞核内具有更高的富集量有关。此外,3个配合物均可有效抑制COX-2的表达,保留了萘普生的抗炎性质,实现了金属配合物抗癌及抗炎的多功能化应用。