碱催化合成N-羟甲基丙烯酰胺的动力学

N-羟甲基丙烯酰胺(N-MAM)具有可聚合的双键和可缩合的羟基,能进一步与其它烯烃化合物反应生成共聚物及交联产物,是一种有重要经济价值的水溶性功能高分子单体。     

Delay induced stability switches in a viral dynamical model

In this paper, a delay-differential mathematical model that described HIV infection of CD4⁺ T cells is analyzed. The effect of time delay on stability of the equilibria of the infection model has been studied. And the sufficient criteria for stability switch of the infected equilibrium and the local and global asymptotic stability of the uninfected equilibrium are given. By using the geometric stability switch criterion in the delay-differential system with delay-dependent parameters, we present that stable equilibria become unstable as the time delay increases. Numerical simulations are carried out to explain the mathematical conclusions.

     

纳米抗菌剂的研究进展

纳米抗菌剂是一种新型高效的抗菌药物,现已逐步应用于纺织、建筑、医疗等各个行业中。传统抗菌方法存在着安全性差、灭菌时间长、操作不方便等缺点,纳米抗菌剂具有使用安全、方便,稳定性好,抗菌谱广和抗菌效力强等优点。综述了纳米抗菌剂的发展概况,展望了纳米抗菌剂发展的主要趋势。     

由4-羟基苯甲醛合成香兰素的CNDO/2研究

用CNDO/2法研究了从4-羟基苯甲醛合成香兰素的化学反应，并作了理论解析。结果表明，合成路线是可行的，总收率为85％。     

微生物食物链培养系统的极限性态

本文考虑多种微生扬在一个培养室中混合培养,这些微生物之间是作为食物链而相依相存的,本文假定营养液的浓度及微生物对资源的消耗率等因素都是时间的有界函数,得到了微生物种群生存和绝灭的条件。     

Selective and rapid ion-chromatographic determinations of alkaline earth metals and applications to the analysis of baryte

Summary An ion-chromatographic procedure is described for the determination of Mg, Ca and Sr in the presence of an excess of Ba in baryte samples after a soda-potash digestion. The procedure is performed by coupling a strong acid exchanger (based on silica gel) and a post-column derivatisation using PAR-Zn-EDTA reagent and photometric detection at 495 nm. Further optimizations resulted in a mobile phase consisting of a citrate-oxalate-ethylendiamine solution. Details of the optimization procedures and the results of some baryte analyses are presented. The concentrations of Mg, Ca and Sr ranged between 0.01 and 2%. These results were verified using two reference methods (AAS and complexometric titration).

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Selektive und schnelle ionen-chromatographische Bestimmungen von Erdalkalimetallen mit Anwendungen in der Barytanalyse

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Dedicated to Prof. Dr. G. Tölg on the occasion of his 60th birthday     

Mechanism and Dynamics of the Addition of Lithium Hydride to Acetylene

Reaction ergodography for the addition of lithium hydride to acetylene indicates that the lithium hydride, in both monomeric and dimeric forms, reacts with the acetylene via two similar and competitive pathways. Hence, we have obtained the pseudo-first-order rate constant of this reaction.     

Ionen-Chromatographie yon Gallium, Indium und Thallium mit Anwendungen in der Erzanalyse

Summary An optimal separation system is presented for the rarer elements Ga(III), In(III), Tl(III) and the main intergrowth elements such as Fe(III), Cu(II), Pb(II), Zn(II) etc., using the cation-exchange column Nucleosil SA and 0.1 mol/l tartrate –0.12% NaCl, pH 2.25, as mobile phase, by means of which complete separations of these metal ions can be obtained within 15 min. Under these chromatographic conditions, the detection sensitivities of these metal ions were compared by post column derivatisation using the reagents PAR, PAR-Zn-EDTA and 5-Br-PADAP [2(5-Bromo-pyridylazo)-5-diethylaminophenol]. The optimum detection system was 1 mmol/l PAR-0.5 mmol/l Zn-EDTA – 2 mol/l NH₃, pH 11, with a 6 m reaction coil heated to 60°C and measured at 495 nm.In addition, a technique of pre-column washing was also developed to eliminate matrix effects of sample solutions, and, if necessary, to concentrate ultra trace amounts of metal ions. A procedure is presented for the simultaneous determination of the rarer elements Ga(III) and In(III) in complex ores. Tested by analyses of synthetic and natural samples with contents of 0.004% to 0.1%, this new method shows high selectivity, good precision, simplicity and practicability.     

The Impact of Media on the Control of Infectious Diseases

We develop a three dimensional compartmental model to investigate the impact of media coverage to the spread and control of infectious diseases (such as SARS) in a given region/area. Stability analysis of the model shows that the disease-free equilibrium is globally-asymptotically stable if a certain threshold quantity, the basic reproduction number (), is less than unity. On the other hand, if , it is shown that a unique endemic equilibrium appears and a Hopf bifurcation can occur which causes oscillatory phenomena. The model may have up to three positive equilibria. Numerical simulations suggest that when and the media impact is stronger enough, the model exhibits multiple positive equilibria which poses challenge to the prediction and control of the outbreaks of infectious diseases. Research supported by the NNSF of China (10471066). Research supported by NSERC, MITACS and CFI/OIT of Canada.     

基于管家式-集约化通信运维平台的设计与实现

随着国网信息化工程建设的推进,越来越多信息系统需要上线转运行,在国网信息化水平踏上新台阶的同时,对于信息运维水平、标准化程度、规范性提出了更高的要求。因此,基于业务与运行保障为中心,研究采用跨平台的J2EE技术结合B/S模式开发环境下的自动化运维平台,设计“管家式-集约化”运维平台整体的技术架构和功能模块,集成了优秀的开源运维工具,给出了部分典型流程并分析其应用成效,最后顺利通过机理评估,该平台实现既有成功整合目前现有分散的专业运维管理子系统的“管家”功能,又改变过去以设备为对象的监控,打破过去各设备系统独立管理的模式,起到“集约”监控作用,形成统一的运维智能监控一体化平台,力图为电企信息运维服务提供高效支撑平台。