基于CT算法的束团横向相空间测量

精确测量束团的发射度和横向相空间, 在高亮度电子束的产生和应用中具有重要意义. 传统测量方法在测量发射度时需要对束团在相空间内分布进行初始假设, 且只能给出相椭圆的twiss参数;基于CT(computerized tomography)算法的束团横向相空间测量方法无需先验假设, 能给出粒子在相空间内的真实分布, 测量结果更为精确. 介绍了基于CT算法的束团横向相空间测量的原理和初步实验结果, 并与四极透镜扫描法测量的结果进行了比较.     

再论生产函数的统计学问题——与余斌、程立茹先生商榷

生产函数有着相应的经济理论背景,是以科学的数据为样本,反复拟合、检验、修正后得到的,揭示产出量与生产要素资本和劳动之间内在的必然的统计相关关系,是科学的结论。本文就此与余斌、程立茹先生进行探讨和商榷。     

Soliton and Periodic Travelling Wave Solutions for Quadratic Nonlinear Media

Many sets of the soliton and periodic travelling wave solutions for the quadratic χ^（2） nonlinear system are obtained by the Backlund transformation and the trial method. The property of the propagation for some travelling waves is investigated.     

Chemoselective Catalytic Hydrogenation of α,β-Unsaturated Ketones and α,β-Unsaturated Carboxylic Esters

ＣｈｅｍｏｓｅｌｅｃｔｉｖｅＣａｔａｌｙｔｉｃＨｙｄｒｏｇｅｎａｔｉｏｎｏｆα，β┐ＵｎｓａｔｕｒａｔｅｄＫｅｔｏｎｅｓａｎｄα，β┐ＵｎｓａｔｕｒａｔｅｄＣａｒｂｏｘｙｌｉｃＥｓｔｅｒｓＺＨＡＮＧＪｉｎｇ－ｗｅｎ＊，ＺＨＡＯＪｉａｎ－ｚｈａｎｇ，Ｚ...     

对称双吡咯甲烷的合成与分子内氢键的研究

５－甲基吡咯－２－羧酸酯在磺酰氢，溴或四乙酸铅作用下，生成相应的在５－甲基上含取代基的产物，后者不经分离不便可自缩合得标题化合物，核磁共振氢谱研究和分子构象木匠，当３，３位的取代基为甲酸（酯）基或乙酸（酯）基时，可形成３，３位酯基与另一吡咯环上的氮氢之间的分子内氢键，而３，３位是其它取代基，如乙酰基，丙酸（酯）基，丁酸（酯）基时不能形成类似的分子内氢键。     

激光二极管泵浦的高重复频率Nd：YAG激光器

报道两个１．５Ｗ连续激光二极管端面泵浦的声光调ＱＮｄ：ＹＡＧ激光器，输出激光脉冲的最高重复频率为３０ｋＨｚ重复频率１ｋＨｚ时，最窄脉宽为１２ｎｓ，最高峰值功率为１２．１ｋＷ。     

THE ELECTRON-BEAM IRRADIATION ON THE HIGH TEMPERATURE SUPERCONDUCTING THIN FILMS: A NUMERICAL SIMULATION OF THE LOW TEMPERATURE SCANNING ELECTRON MICROSCOPY

Low-temperature scanning electron microscopy (LTSEM) is a promising measuring technique for probing the spatial distribution of the superconducting properties of the high-temperature superconducting (HTS) thin films. A theoretical analysis of the electron-beam irradiation on the HTS thin films in the LTSEM has been carried out. An inhomogeneously distributed grain array model has been applied in the analysis, and some numerical sim-ulations have been carried out on the electron-beam induced voltage (EIV) signals in the LTSEM experiments. The comparisons of our numerical results with the LTSEM experi-mental data indicate that it is quite reasonable to use a two-dimensional Josephson junction array for stimulating the inhomogeneous HTS thin film sample. Our numerical results also show that the EIV signals are influenced by the electron-beam power used in the LTSEM, and a reduction of the electron-beam power is suggested in order to eliminate the errors in estimating the local values of critical temperature T_c and critical current I_c by the sample temperature and the bias current at which the first EIV signal occurs.     

Renormalization group calculation of the critical temperature dependence on longitudinal magnetic field for a disordered superconductor model

We describe a calculation ofT _c (P, H) in a model of a disordered superconductor which is based on the de Gennes-Skal-Shklovskii (dGSS) picture of the large cluster in a percolation system. The calculation is done by carrying out successive decimations on the Landau-Ginzburg Hamiltonian describing the links in the model. We calculateT _c (P, H) in the presence of longitudinal magnetic field by evaluating the renormalized Landau-Ginzburg coupling when the renormalized Landau-Ginzburg length equals the percolation link length in the dGSS picture and obtain the approximate analytic form ofT _c (P, H).Work supported by China Natural Science Foundation     

非相干光源用于“核-环比”法测量表面粗糙度

本文将文献[1-5]的用激光测量表面粗糙度的“核-环比”法推广到采用其他非相干光源,给出测量原理的定量公式及测量装置的结构框图。