有机磷化合物的NMR研究Ⅵ.1,3,2-氧氮磷杂环戊烷的13C谱

测定了19个2-硫代-2-(二乙基氨基)-3-取代苯甲(磺)酰基-1,3,2-氧氮磷杂环戊烷的¹³C NMR参数.在苯甲酰类化合物中,邻位有非氢取代基时,非环的²J(PNC)随温度而变化(0~6.1Hz),这是因羧基与苯环空间位置(构象)随温度变化所致.     

渐变折射率波导传播特性微扰计算的代数递推公式

应用量子力学的超位力定理（HVT）和赫尔曼－费恩曼（Hellmann-Feynman）定理（HFT），导出了用微扰法计算渐变折射率平面波导传播常数各级近似值的代数递推公式，并给出了由传播常数近似值计算模场近似表达式的代数式。计算了几个典型实例，此法的特点是便于直接计算任意级近似的传播常数及模场分布，且可推广到二维波导的计算。     

STABILITY IN DIFFERENTIAL EQUATIONS WITH CONTINUOUS AND PIECEWISE CONSTANT ARGUMENTS

ＳＴＡＢＩＬＩＴＹＩＮＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＣＯＮＴＩＮＵＯＵＳＡＮＤＰＩＥＣＥＷＩＳＥＣＯＮＳＴＡＮＴＡＲＧＵＭＥＮＴＳＭｉｎｇ－ＰｏＣｈｅｎＳＴＡＢＩＬＩＴＹＩＮＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＣＯＮ...     

A local spin evaluation into the active site models of [2Fe2S] ferrodoxin [Fe_2S_2(SR)_4]~(2-) (R=-H, -CH_3)

To test the feasibility of local spin theory of Davidson and Clark for ferrodoxin clusters, the models [Fe2S2(SR)4]2- (R=-H, -CH3) are chosen for evaluation. This purpose is realized by calculating the local spin expectation values , , and mA and discussing the connection between these expected values and the Heisenberg spin model (HSM) and the Noodleman broken-symmetry approach. In practical calculation, the spin-unrestricted Hartree-Fock (UHF) and spin-polarized density functional theory (DFT) are used and the calculational qualities of these two methods are also discussed. In addition, the theoretical magnetic coupling constants JAB of these models are calculated by various computational schemes for comparison with both theoretical and experimental results previously reported.     

新型径向柱塞变量泵恒功率控制机构的方案比较与分析

本文详细比较了国内外出现的四种恒功率控制方案 ,给出了系统原理图 ,作了特性比较说明 ,并就工程实用性角度出发设计了一套位移 力矩反馈式恒功率控制机构。给出了其调节特性曲线 ,并就它的设计参数及思路给了概略介绍     

反应动力学参数的热动力学法探讨

基于简单级数反应的积分和微分热动力学方程，运用热动力学特征对比参量法的数学模型，通过乙酸乙酯皂化等不同级数反应的热谱曲线确定特征时间参量tm，再由此计算出特征对比热量R，既可计算反应的速率常数等．这些反应的热动力学研究验证了方法的正确性。     

The characterization of binary constant weight codes meeting the bound of Fu and Shen

Fu and Shen gave an upper bound on binary constant weight codes. In this paper, we present a new proof for the bound of Fu and Shen and characterize binary constant weight codes meeting this bound. It is shown that binary constant weight codes meet the bound of Fu and Shen if and only if they are generated from certain symmetric designs and quasi-symmetric designs in combinatorial design theory. In particular, it turns out that the existence of binary codes with even length meeting the Grey–Rankin bound is equivalent to the existence of certain binary constant weight codes meeting the bound of Fu and Shen. Furthermore, some examples are listed to illustrate these results. Finally, we obtain a new upper bound on binary constant weight codes which improves on the bound of Fu and Shen in certain case. This research is supported in part by the DSTA research grant R-394-000-025-422 and the National Natural Science Foundation of China under the Grant 60402031, and the NSFC-GDSF joint fund under the Grant U0675001     

带常数项的最优加权组合预测

We propose a model based on the optimal weighted combinational forecasting with constant terms,give formulae of the weights and the average errors as well as a rela- tion of the model and the corresponding model without constant terms,and compare these models.Finally an example was given,which showed that the fitting precision has been enhanced.     

空心介质球对静磁场的屏蔽

文章通过对空心介质球的静磁场屏蔽进行理论推导，并分析静磁场屏蔽的因素．