无控火箭落点控制初探

介绍了被动段火箭质心运动方程，对火箭弹道被动段、尤其是被动结束段的解法作了详细介绍，并给出了相关的精度分析。最后提出了无控火箭的简易控制设想，为有关研究提供参考。     

Excitation of Complicated Shapes in Three Dimensions

We experimentally verified a recently proposed technique for the excitation of a complicated three-dimensional profile (CARVE,completelyarbitraryregionalvolumeexcitation). CARVE is based on a generalized DANTE RF pulse sequence and a synchronous string of gradient steps. Provided there is no limitation in the number of pulses, CARVE can generate an excitation profile of any shape with any resolution. However, hardware limitations and sample properties restrict the number of RF pulses and gradient steps and, thus, limit attainable resolution of the excitation profile. We theoretically and experimentally showed that spatial resolution can be increased by distributing a long sequence among several CARVE experiments and summing up their signals. This is particularly important for three-dimensional excitation profiles where ann-fold increase in resolution requires ann³-fold increase of the number of events in the sequence. The potential use of three-dimensional CARVE might be in spectroscopic imaging where the excitation profile can be tailored to match the shape of a selected organ or body part.     

Analysis of nonlinear beam-wave interaction of gyro-peniotron at harmonics

An analysis of the nonlinear beam-wave interaction of the gyro-peniotron at high harmonic is presented in this paper. It bases on a ballistic large-signal theory of the gyropeniotron assuming a given RF field distribution in the resonator. The proposed method is applicable to arbitrary harmonic numbers and to arbitrary TE modes. Analytical results of its operational characteristics are given using computer simulations. E. g. an efficiency of 45% for the third harmonic has been calculated. The results show that the gyro-peniotron could be potentially a high efficiency, high power millimeter-wave device at a low magnetic field.     

飞行器惯导数据在海上靶场测控中的应用

某型飞行器在海上靶场试验中的突出特点是舰载发射、低空、快速(约6马赫)。由于低仰角起始段雷达捕获困难,需要准确的引导数据作为捕获保障。在飞行器试验中,惯导数据插入遥测数据中进行实时传送,利用遥测数据中惯性导航数据实时处理,其结果可以用来解决海上靶场飞行器外弹道轨迹显示,并将其作为引导数据,引导雷达在初始段对目标进行快速捕获。     

用图像研究非线性迭代模型

用蛛网图、迭代函数图、周期分叉图以及分布直方图等几何图像研究了L og istic模型的迭代轨道,研究了非线性迭代轨道进入混沌状态的条件.     

内点算法和动力系统

本文以动力系统的理论统一处理各种解线性规划的内点算法.在一般情况下讨论了此类系统的构成和基本的附加条件.对轨线的几何特征,尤其是它们在靠近边界处的动态作了进一步研究.     

Landau levels line widths in potential scattering in the presence of a strong magnetic field

Summary The FBA scattering cross-section in the presence of a strong magnetic field diverges at the Landau thresholds. Such divergences are eliminated by the introduction of a modified density of states, accounting for the finite Landau states lifetime of the electrons in a magnetized plasma.     

Numerical simulations of gas-particle flows with combustion

This work is devoted to the numerical modelling of a reactive gas-particle flow that arises in internal ballistic. The model, proposed by Gough [2], takes into account complex physical phenomena such as mass transfer, drag force or intra granular stress. A non-conservative finite volume approach adapted from [11] is applied in order to simulate the model. After an academic validation test case of the scheme, the combustion propagation ignited by a cylindrical perforated primer is then simulated and compared with experiments.     

The curvature integral and the complexity of linear complementarity problems

In this paper, we propose a predictor—corrector-type algorithm for solving the linear complementarity problem (LCP), and prove that the actual number of iterations needed by the algorithm is bounded from above and from below by a curvature integral along the central trajectory of the problem. This curvature integral is not greater than, and possibly smaller than, the best upper bound obtained in the literature to date.Corresponding author.This author's research was partially supported by Research Grant No. RP920068, National University of Singapore, Singapore.     

ODE versus SQP methods for constrained optimization

In this paper, we review some methods which are designed to solve equality constrained minimization problems by following the trajectory defined by a system of ordinary differential equations. The numerical performance of a number of these methods is compared with that of some popular sequential quadratic programming algorithms. On a set of eighteen difficult test problems, we observe that several of the ODE methods are more successful than any of the SQP techniques. We suggest that these experimental results indicate the need for research both to analyze and develop new ODE techniques and also to strengthen the currently available SQP algorithms.This work was supported by a SERC Research Studentship for the first author. Both authors are indebted to Dr. J. J. McKeown and Dr. K. D. Patel of SCICON Ltd., the collaborating establishment, for their advice and encouragement.