Classical Limit of Expectation Values in a Wave Packet Involving Few Stationary States

Expectation values of physical quantities in a wave packet involving few stationary states in an infinite square well are calculated. Explicit results show that the expectation values in the classical limit go over to the corresponding classical quantity in the form of the arithmetic mean (in mathematical term, the Fejér's average) of the partial Fourier series converging to the classical quantity. The number of the stationary states is that of the partial Fourer series in the Fejér's average. The quantum uncertainty is then demonstrated to have a classical counterpart.     

均匀分层介质中标准矢量波函数的构成

研究了在均匀分层介质中构成标准矢量波函数的必要条件。研究结果表明在均匀分层介质中构成标准矢量波函数一般需遵循Morse-Feshbach判据外，领示矢量只能选取与折射率变化方向一致的那根坐标轴单位矢量。但在某些特定的条件下，对领示矢量的选取条件可以放宽为只需遵循Morse-Feshbach判据即可。     

软x射线近贴显微技术

软x射线近贴显微技术不但可使活的生物样品成象,分辨率高于光学显微镜,而且人为的样品准备程序在该技术中都可避免。本文描述了用高功率激光打靶产生的等离子体作为软x射线源而进行的近贴显微研究,并得到了分辨率好于1μm的结果。     

火焰原子吸收法测定人体胆结石中的铜、锌、钙、镁

本文介绍了火焰原子吸收法测定人体胆结石中铜、锌、钙、镁元素含量的测试条件及介质的影响，测试结果表明该方法具有较好的准确度和精密度，适合于医学临床应用。     

资源有限网络计划的PRWI启发式优化方法

本文在综合考虑了有资源约束的网络计划结构特征、资源强度、时间约束等方面因素的基础上，提出了一种新的资源优化的启发式优化方法—ＰＲＷＩ方法，并通过分析证明了该方法处理问题的效果较现有的其它方法好。     

Third order nonoscillatory central scheme for hyperbolic conservation laws

Summary. A third-order accurate Godunov-type scheme for the approximate solution of hyperbolic systems of conservation laws is presented. Its two main ingredients include: 1. A non-oscillatory piecewise-quadratic reconstruction of pointvalues from their given cell averages; and 2. A central differencing based on staggered evolution of the reconstructed cell averages. This results in a third-order central scheme, an extension along the lines of the second-order central scheme of Nessyahu and Tadmor \cite{NT}. The scalar scheme is non-oscillatory (and hence – convergent), in the sense that it does not increase the number of initial extrema (– as does the exact entropy solution operator). Extension to systems is carried out by componentwise application of the scalar framework. In particular, we have the advantage that, unlike upwind schemes, no (approximate) Riemann solvers, field-by-field characteristic decompositions, etc., are required. Numerical experiments confirm the high-resolution content of the proposed scheme. Thus, a considerable amount of simplicity and robustness is gained while retaining the expected third-order resolution. Received April 10, 1996 / Revised version received January 20, 1997     

多电子束契伦柯夫自由电子激光振荡器

我们对多电子束契伦柯夫自由电子激光进行了首次实验研究。280A,500kV的电子束被引入一多介质矩形谐振腔,在频率为33.4GHz处产生了1.7MW的契伦柯夫相干受激辐射。互作用效率为1.2％。     

Unique edge structure and stability of fabricated dimer islands on Si(001)

The edge structure and stability of monolayer-high islands fabricated on Si(001) surfaces by scanning tunneling microscopy have been analyzed theoretically. In contrast to the edges of similar islands grown by depositing Si, the properties of edges of fabricated islands are determined by the length of the trench of dimers that are removed to create the island. We demonstrate the possibility of controlling the edge structure, and thus the stability, through a selective process of atom removal.     

G(F4′)条件与加强形式的停止定理

首次提出了Ｇ（Ｆ４′）条件，给出了Ｇ（Ｆ４′）条件的两个等价关系，得到了加强形式的停止定理和强鞅的一个等价关系．