锰(Ⅱ)-高碘酸钾-灿烂绿体系测定水中痕量锰

在 HAc- Na Ac环境中 ,锰 ( )对于高碘酸钾氧化灿烂绿的反应具有很强的催化作用。据此 ,建立了催化动力学光度法测定痕量锰 ( )的新方法。该方法的检出限为 2 .2 2× 10 -11g/ m L ,测定线性范围为0 .1— 12 ng/ m L。直接用于环境水样中锰的测定 ,获得满意的结果     

von Neumann代数中套子代数上的Lie同构

本文给出因子von Neumann代数中的幂等算子在广义Lie积下的一个刻画; 得到因子von Neumann代数中套子代数的幂等算子在Lie积下的一个特征．作为应用, 研究了因子von Neumann代数中套子代数上的Lie同构,并证明因子von Neumann 代数中套子代数之间的Lie同构,要么是同构与广义迹之和,要么是负反同构与广义迹之和．     

Measurement of small-signal and large-signal responses of packaged laser modules at high temperature

In this paper, the pulsed injection method is extended to measure the chip temperature of various packaged laser modules, such as the DFB laser modules, the FP laser modules, and the EML laser modules. An optimal injection condition is obtained by investigating the dependence of the lasing wavelength on the width and period of the injection pulse in a relatively wide temperature range. The small-signal frequency responses and large-signal performances of packaged laser modules at different chip temperature are measured. The adiabatic small-signal modulation characteristics of packaged LD are first extracted. In the large-signal measurement, the effects of chip temperature, bias current and driving signal on the performances of the laser modules are discussed. It has been found that the large-signal performances of the EML modules depend on the different red-shift speeds of the DFB and EAM sections as chip temperature varying, and the optimal characteristics may be achieved at higher temperature.     

垂直低温两相流管底液氮汽泡上升速度的实验研究

本文对垂直低温两相流管底部液氮汽泡的上升速度运用高速摄像机进行了可视化实验研究,对所采集的实时图像进行处理.在Cole和Mendelson汽泡上升速度经验公式的基础上,通过对液氮汽泡的上升速度的分析,提出了圆管管路底部液氮汽泡的上升速度的拟合公式,分析研究其变化规律,为进一步探求圆管内液氮弹状汽泡的生成机理提供依据.     

A rule-based risk decision-making approach and its application in China's customs inspection decision

This paper addresses a kind of risk decision-making problem existing widely in public administration and business management, which is characterized by (1) occurrence probabilities of states of nature can be estimated by analysing historical observations, but historical observations of different objects are unhomogeneous, (2) the relation between observations and occurrence probabilities of states of nature are affected by some qualitative and quantitative indicators, (3) it is a real-time decision-making problem, that is, there are many decisions for different objects to be made in a limited time, (4) considering decision's execution, impact of resource constrains is an important issue in decision-making process. In this paper, we develop a rule-based approach to address the problem. In the proposed approach, a two-step clustering method is employed to classify objects into categories, and observations in each category can be approximately viewed as homogeneous. For objects in each category, occurrence probabilities of states of nature are estimated by logistic regression, and the decision rule is obtained through solving an optimization model, which is to minimize the total decision risks while satisfying resource constrains. Effect and efficacy of our approach are illustrated through its application to China's customs inspection decision.     

Novel photoswitching dithienylethenes with ferrocene units

Two novel dithienylethenes with ferrocene units were synthesized by Wittig reaction. The structure of 2a has been established by X‐ray diffraction studies. They could reversibly interconvert between two thermally stable forms, an open and a closed one, using light of different wavelengths as triggers. Copyright © 2006 John Wiley & Sons, Ltd.     

Bioisosterism between Sulfonyl Group and Phosphoryl Group-The Synthesis of New ALS Inhibitors N-(Arylamino Hydroxyl Phosphoryl)-N'-(4,6-Dimethoxypyrimidine-2-yl)ureas

Sulfonylureaherbicidesisanewclassofherbicidesdiscoveredinthemid-l97O's',whosemodeofactionhasbeenestablishedastheinhibitionofacetolactatesynthase(ALS,alsoreferredasacetohydroxyacidsynthase)'-Muchattentionhasbeenfocussedonthiskindofcompound,sincetheyhaveunprecedenteduserates,ahighdegreeofselectivity,andexcellentenvironmentalsafety'.NumerousmodificationsofthestrUctureofthisclassofherbicideshavebeenreported'.Wehavetakenattentiontothesimi1alltybetweenthesulfonylgroup(-SO2-)andphosphoryIgroup[-P…     

A Novel Method to Synthesize Polyorganozircosilazane

A new kind of polyorganozircosilazane as Si/Zr/C/N-based ceramic precursor was synthesized from the condensation reaction of hexamethyleyclotrisilazane lithium salts(D3^NLi）and zirconium tetrachloride(ZrCl4).In the presence of N,N,N’,N’-tetramethyl ethylene diamine(TMEDA),polyorganozircosilazane was obtained in high yield.     

氯离子柱撑水滑石共沉淀法合成反应动力学

根据氯离子型层状复合氢氧化物(LDH-Cl)制备过程中溶液浓度变化的监测结果和不同反应进程时产物的EDS、IR、XRD、TEM、TG-DTA表征结果,研究了合成LDH-Cl的共沉淀反应动力学特征及机理.实验结果表明, LDH-Cl的生成符合多核层表面反应动力学模型;反应过程中LDH的晶胞参数c从2.421 nm变为2.399 nm,通道高度h由0.3321 nm减小为0.3228 nm,粒子直径Da由6.40 nm增大为15.16 nm, Dc由7.43 nm增大到10.93 nm,纵横比由0.86增大为1.39; IR和TG-DTA特征变化表明了层板对阴离子作用的强度和层板的结构稳定性随反应进程而提高.