双组元姿控发动机反流特性的DSMC模拟

为准确获得双组元姿控发动机的羽流及其反流特性,采用直接模拟蒙特卡罗(DSMC)方法结合可变软球(VSS)模型数值模拟以N2O4/MMH为推进剂的真空羽流。喷口参数由喷管流动的DSMC法计算得到。与文献比较表明本文计算程序可信。模拟结果表明,分子质量越小的气体越容易进入反流区;本文的计算条件下,在偏离X轴正向116°~140°范围内,组分数密度和质量流率以及温度均出现了最大值。     

Reaction Mechanism Investigation Using Vibrational Mode Analysis for the Multichannel Reaction of CH_3O+CO

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｍｅｔｈｏｘｙｒａｄｉｃａｌ (ＣＨ3Ｏ)ｉｓａｎｉｍｐｏｒｔａｎｔｉｎｔｅｒ ｍｅｄｉａｔｅｉｎｔｈｅｐｈｏｔｏｃｈｅｍｉｃａｌｏｘｉｄａｔｉｏｎｏｆｈｙｄｒｏｃａｒｂｏｎｓｉｎｔｈｅａｔｍｏｓｐｈｅｒｅ ,1 3ａｎｄｐｌａｙｓａｓｉｇｎｉｆｉｃａｎｔｒｏｌｅｉｎｔｒａｎｓ ｆｏｒｍｉｎｇｎｉｔｒｉｃｏｘｉｄｅｔｏｎｉｔｒｏｇｅｎｄｉｏｘｉｄｅ .4 Ｓｉｍｉｌａｒｌｙ ,ｔｈｅｒｅａｃｔｉｏｎｍｅｃｈａｎｉｓｍｓｏｆｈｙｄｒｏｘｙｌａｎｄｃａｒｂｏｎｍｏｎｏｘｉｄｅ5,6ａｎｄｏ…     

基于零点的函数K图和dj图的转换

介绍了函数的最大项展开式和CRM展开式及其图形表示，提出函数K图和dj图的零点的概念，并以此为基础讨论了基于零点的函数K图和dj图之间的转换方法。     

广义非简谐振子的多尺度微扰理论

应用多尺度微扰理论到广义非简谐振子, 得到了一阶经典和量子微扰解. 特别是 我们的量子解在极限条件下能方便地转变为经典解, 并且坐标和动量算符的对易 关系的简化十分自然. 与Taylor级数解相比较, 无论是在经典还是在量子解 中频率移动都出现在各阶振动表达式中, 所以多尺度微扰解是弱耦合非简谐振动的较好解法.     

HL-2A װ��MW ������������ϵͳ��˿��Դ�����������

The main circuit topology, control hardware and control sequence of the cathode filament power supply for the HL-2A neutral beam heating system was introduced. Feedback control simulation of main circuit of filament power supply is carried out through MATLAB simulation software. It is found that the ripple factor is about 1%when the current is about 1000A, and the ripple coefficient increases to 3% when the current drops to 200A. Without the AC filter reactor in series L₁ and parallel harmonic filter LC in the low level control cabinet, the output current ripple coefficient becomes larger obviously. It shows that L₁ and LC not only absorb harmonic current, but also filter the chopper waveform after AC voltage regulation to make the output waveform smoother.     

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.     

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。     

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.