运用严格耦合波理论计算平面电介质光栅的衍射效率

本文阐述了严格耦合波理论的基本思想。针对横电波的情况，详细分析了运用严格耦合波理论实现光栅衍射效率计算的方法，并且进一步给出了编制计算衍射效率程序的步骤。通过一个具体计算实例表明：各衍射级分布的光能量之和等于入射光的能量，满足能量守恒定律，从而证实了计算结果的正确性。     

On the Snider equation

We study the physical content of the Snider quantum transport equation and the origin of a puzzling feature of this equation, which implies contradictory values for the one-particle density operator. We discuss in detail why the two values are in fact not very different provided that the studied particles have sufficiently large wave packets and only a small interaction probability, a condition which puts a limit on the validity of the Snider equation. In order to improve its range of application, we propose a reinterpretation of the equation as a mixed equation relating the real one-particle distribution function (on the left-hand side of the equation) to the free distribution (on the right-hand side), which we have introduced in a recent contribution. In its original form, the Snider equation is valid only when used to generate Boltzmann-type equations where collisions are treated as point processes in space and time (no range, no duration); in this approximation, virial corrections are not included, so that the real and free distributions coincide. If the equation is used beyond this approximation to generate nonlocal and density corrections, we conclude that the results are not necessarily correct.     

Recursive solution of linear-quadratic Nash games for weakly interconnected systems

A recursive method is developed for the solution of coupled algebraic Riccati equations and corresponding linear Nash strategies of weakly interconnected systems. It is shown that the given algorithm converges to the exact solution with the rate of convergence ofO(²), where is a small coupling parameter. In addition, only low-order systems are involved in algebrdic computations; the amount of computations required does not grow per iteration and no analyticity assumption is imposed on the system coefficients.This work was supported by Rutgers University Research Council under Grant No. 2-02188.     

Directed polymers in Hartree-Fock approximation

A replica trick is used to map the problem of directed polymers into a quantum mechanics problem ofn-body bound states. This bound-state problem is then treated using a self-consistent method of Hartree-Fock. Ford=2, the exact result of the DP exponents is reproduced; and for complex DP, the ground-state energyE _n n² is found, confirming previous numerical results.     

外电场下光聚合反应动力学的表征方法

外电场下光聚合反应动力学的表征方法李从武，潘昂上海材料研究所，上海２０００８２）关键词光聚合反应、液晶、外电场、动力学、表征近年来，液晶单体在外场（电场、磁场和剪切力）下在位光聚合反应的研究工作受到了很大的关注［’，ＺＩ．众所周知，热致型侧链高分子液...     

电感耦合等离子体原子发射光谱分析中不同电离电位元素基体效应的比较研究

选择不同电离电位的基体元素K、Na、La、Y和Mg,比较研究了它们对分析元素谱线强度的影响,其影响程度与谱线激发电位及基体元素电离电位有定量的相关关系。碱金属基体(K、Na)和非碱金属基体(La、Y和Mg)对分析元素检出限、背景强度及其相对标准偏差的影响显著不同,后者的记忆效应也大于前者。La的电离电位与Na相差不大。但其基体效应与Y相似,表明墓体效应与基体元素的化学性质有关。     

氢化物发生电感耦合等离子体原子发射光谱同时测定纯铜中氢化物和非氢化物形成元素

用新型氢化物发生喇叭口Ⅱ型同心雾化器替代Meinhard同心雾化器，溶液雾化为气溶胶和氢化物发生反应生成氢化物气体就可以在雾化系统中同时进行，选用L-巯基丙氨酸(L-cysteine)和硫脲(thiourea)作为基体铜的掩蔽剂，无需分离基体铜，实现了电感耦合等离子体原子发射光谱(ICP-AES)同时测定纯铜样品中氢化物和非氢化物形成元素的目的。研究了酸度、NaBH4的浓度、载气流速及清洗时间对氢化物形成元素的影响，考察了铜基体对氢化物形成元素的化学干扰情况。用本方法测定了纯铜标准样品(NIST SRM400)，结果令人满意。在1000mg/L纯铜样品溶液中，其氢化物形成元素As、Bi、Sb、Sn、Se和Te的检出限分别为0．08、0．15、0．10、0．17、0．21和0．23μg／L。     

8-羟基喹啉-5-磺酸纤维微柱分离富集电感耦合等离子体原子发射光谱法同时测定多种痕量元素

本文合成了8-羟基喹啉-5-磺酸纤维滤纸片,以此做为微柱填充物同时富集了10种痕量元素,并分离了样品中的高盐组分.本方法可使痕量组分的分离与富集同步进行,因而特别适用于原子光谱测定前样品的预处理.     

Accuracy and long-term reproducibility of lead isotopic measurements by multiple-collector inductively coupled plasma mass spectrometry using an external method for correction of mass discrimination

The precision of isotopic measurements of Pb by thermal ionization mass spectrometry (TIMS) is limited by the fact that this element does not possess an invariant isotope ratio that can be used for the correction of mass fractionation by internal normalization. Multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) can overcome this limitation, because with plasma ionization, elements with overlapping mass ranges are thought to display identical mass discrimination. With respect to Pb, this can be exploited by the addition of Tl to the sample solutions; the mass discrimination factor obtained for Tl can then be used for the correction of the measured Pb isotope ratios. In this article we present the results of a detailed study that investigates the accuracy and precision of such an external correction technique for mass discrimination based upon the results of multiple analyses of a mixed standard solution of NIST SRM-981 Pb and SRM-997 Tl. Our data indicate that normalization of the Pb isotope ratios to the certified isotopic composition of SRM-997 Tl produces Pb isotopic results that are significantly lower than recently published reference values by TIMS. This systematic offset can be eliminated by renormalization of the Pb data to a different Tl isotopic composition to obtain an empirically determined mass discrimination factor for Pb that generates accurate results. It is furthermore shown that a linear law is least suited for the correction of mass discrimination, whereas a power or exponential law function provide significantly more accurate and precise results. In detail, it appears that a power law may provide the most appropriate correction procedure, because the corrected Pb isotope ratios display less residual correlations with mass discrimination compared to the exponentially corrected data. Using an exponential or power law correction our results, obtained over a period of over seven months, display a precision (2σ) of better than 60 parts per million (ppm) for ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/²⁰⁶Pb and of better than 350 ppm for ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb. This represents a significant improvement compared to conventional TIMS techniques and demonstrates the potential of MC-ICPMS for routine, high-precision measurements of Pb isotopic compositions.     

氨基羧酸纤维分离富集-电感耦合等离子体原子发射光谱法测定多种痕量稀土元素

本文制备了氨基羧酸纤维滤纸片作为柱填充物，成功地分离和富集了地化样品中的多种稀土元素。富集后的稀土元素采用电感耦合等离子体原子发射光谱法测定，回收率为90％～109％。本文还对基体干扰及其消除进行了研究。