船舶参数激励横摇运动研究综述

为避免参数激励导致船舶出现不稳定横摇,提出有效抑制参数横摇的方法.分析参数激励引起的大幅横摇运动的动力特性,从船舶非线性耦合运动、横浪运动、纵浪上参数激励运动和波浪上参数与波浪联合激励运动方面,对目前研究现状及取得的主要成果进行综述,对船舶参数激励横摇运动及其倾覆机理的研究前景进行展望.     

地下结构地震动力响应中地震波的分析研究

地下结构地震动力响应分析首先需要对地震波进行合理的分析,其主要包括地震波的选择、波的频谱分析、滤波和基线校正4个方面,这是正确进行地下结构地震动力分析的非常关键的环节.以课题研究中地震局提供的地震波为例,从多个方面分别对地震波进行分析和研究,从而获得满足地下结构地震动力分析要求的地震波.     

一类交叉单稳型时滞格微分方程行波解的存在性

通过构造两个拟单调的上下控制方程并利用Schauder不动点定理, 给出并证明了一类交叉单稳型时滞格微分方程行波解的存在性. 结果表明, 即使对这类交叉单稳型的格微分方程, 行波解对所有时滞持久存在.     

基于Hough变换的低可观测海面运动目标检测

针对一般信号检测方法无法检测低可观海面运动目标的问题,提出了运用Hough变换方法对海杂波背景下运动目标进行检测的方法。首先,用无记忆非线性变换法模拟海杂波,在此基础上模拟海面微弱运动目标的雷达回波;然后通过Hough变换对模拟所得的雷达回波数据进行处理;并根据处理结果进行了检测目标。另外用蒙特卡罗方法对Hough变换目标检测进行仿真,讨论了检测概率与雷达回波信噪比(SNR)及其它一些参量的关系。仿真结果证明了用Hough变换方法进行目标检测的可行性。     

Electromagnetic ion-cyclotron instability driven by combined loss-cone and temperature anisotropy distribution of suprathermal ions

Electromagnetic ion cyclotron (EMIC) waves, particularly their generation and excitation mechanisms, have been a subject of wide interest because of their potential importance in ion acceleration and heating. In this work, the parameter-dependence of EMIC instabilities is investigated with a combined loss-cone and temperature anisotropy distribution for suprathermal ions. The calculation of the linear growth rate of EMIC waves with an arbitrary propagation angle is presented. The results show that the growth rates of EMIC waves propagating quasi-perpendicular to the ambient magnetic field increase as the loss-cone parameter α increases, whereas the growth rates of EMIC waves propagating quasi-parallel to the ambient magnetic field increase as the temperature anisotropy parameter A _T increases. This indicates that the free energies associated with the loss-cone and temperature anisotropic distributions are primarily responsible for the excitation of the quasi-perpendicular and parallel propagating EMIC waves, respectively, and provides us with a more comprehensive understanding of excitation and generation mechanisms for EMIC waves in space plasmas.     

Scaling of the pieces of the Aristotle's lantern in five species of Strongylocentrotus (Echinodermata: Echinoidea)

The lengths of the demipyramids and rotules and the weights of the demipyramids, rotules, epiphyses, compasses, and teeth of the Aristotle's lantern from Strongylocentrotus droebachiensis, S. franciscanus, S. intermedius, S. nudus and S. purpuratus over a size range of 46–76 mm horizontal diameter were measured. The rates of increase in size of the lantern pieces of S. franciscanus when scaled with increase in body size are greater than those of the other species. The growth of S. franciscanus to a much larger body size and its continued increase in relative gonadal production at a size at which it ceases in S. intermedius and S. purpuratus may result from a greater feeding capacity related to the size of the lantern pieces.     

某些生长系统的数学模型及其单元自动机动态模拟

本文用单元自动机模拟［１－４］了海贝壳的图案形成，给出了其数学模型，并得到了其动态图形结果     

浙江省渔船海上交通事故隐患因子的调查研究

采用问卷调查，管理部门调查，渔船实地调查相结合的调查方法，运用安全系统工程学理论，阐述了浙江省渔船海上交通事故现状及特点，分析研究了事故存在的隐患因子，并提出控制事故隐患的对策措施。     

现代干涉度量术在会聚冲击波观测中的应用

在阐述现代干涉度量术的原理及其会聚冲击波的特点、会聚圆柱形冲击波的数字模拟方程式基础上，利用现代干涉技术设计了一种用于观测圆柱形冲击波的干涉仪，观测了会聚圆柱形冲击波不稳定性的全过程，得到了清晰的干涉图像，并对该测试系统获得的实验干涉图、圆柱形冲击波的畸变以及此测量过程所产生的马赫盘作了分析讨论．给出了关于会聚冲击波的三相点、随机的马赫数等结论．     

Premonitory phenomenon of EI Niño event reflected in the observations ofLOD and sea level

Data sets of the changes of the length of day, the sea surface temperature in the eastern Pacific and of the sea level in Hong Long from tide gauge observations are used to analyze and reveal the reflections in the observations of the length of day and the sea level changes concerned with the premonitory phenomenon of next EI Niño event. The results from this study indicate that a new EI Niño event has been brewing with the ending of the strong La Niño event that started in early summer of 1998. The estimated formation period of the new EI Niño event will begin before the end of 2000, and the peak period may be reached at around the end of 2001.