Analytically derived wind-wave directional spectrum part 1. Derivation of the spectrum

In contrast with the usual method to obtain the wind-wave directional spectrum by multiplying the frequency spectrum with an empirical directional function, the authors attempt to derive analytically the directional spectrum by adopting proper spectral form and using effective parameters, namely, the zero order momentm ₀ of the wind-wave frequency spectrumS(), its peak frequency ₀ and the so-called peakness factorP=₀ S(₀)/m ₀, where is angular frequency. The directional spectrum is given in a form of frequency spectrum for each direction. The spectral directionality depends on, in addition to frequency, the wind-wave growth status, for the peakness factorP as introduced by the authors previously is a measure of the wave development stage. The salient features of the directional spectrum, comparison with existing formulas and the verification of the spectrum by observational data are to be given in the Part 2 of the paper.Project supported by the National Natural Science Foundation of China.     

基于分块分形编码的多姿态、表情人脸图像检索

利用图像分形编码中定义域块和最小均方误差一一对应的特点，提出了1种基于分形编码的多姿态、表情的人脸图像检索方法。该方法将待检索图像分割为相同大小的值域块，然后将每一值域块按给定的定义域块进行分形编码，得到最小均方误差，计算该最小均方误差与图像库中最小均方误差的欧氏距离。将待检索图像所有值域块的欧氏距离求平均，此平均欧氏距离较小的几幅图像即为检索出的图像。实验证明该方法能够准确地检索出图像库中存储的同一人的不同姿态、表情的图像。     

混凝土的渗透性与耐久性

渗透性是混凝土耐久性中最重要的内容。论述了混凝土耐久性的影响因素、研究方法 ,以及混凝土渗透机理和渗透性与耐久性的关系。     

中太平洋海山群漂移史及其来源

中太平洋海山群的海山呈簇状排列且近EW向展布于太平洋海山密集区，其四周分布着一系列NW走向的线性列岛及规模巨大的水下海山链。它位于明显属于海山链构造的夏威夷群岛和马绍尔群岛之间，处于莱恩群岛的北西向延伸方向上，与热点作用的板内火山作用关系密切。结合前人对中太平洋海山群形成和漂移的认识，从板块运动和几何学角度出发，采用Backtracking和Hot-spotting海山追踪方法对该区海山进行了追踪，发现该区海山的热点源主要位于现今法属玻利尼西亚群岛区（法属玻利尼西亚热点群），这与前人从古地磁和钻探资料出发得到的结果相接近。研究表明，中太平洋海山群是多热点成因的板内火山作用和板块构造运动的共同产物，它在130～90Ma期间起源于法属玻利尼西亚热点群，曾随着太平洋板块发生过向南和向北的运动，既有水平方向的漂移又有垂直方向上的升降，在漂移和升降过程中还受到了当时大规模多期的热点活动和断裂活动的改造作用，经过一个漫长的过程后才到达今天的位置，最后形成了现今呈簇状分布的海山群。     

青岛市水环境污染及其防治对策

通过分析近几年青岛市地表，地下水水质监测资料，总结水环境污染地区分布规律，摸清水环境污染形成原因，对当前防污治污工作提出了对策建议。     

扇贝提取物对实验性高脂血症大鼠血脂及脂质过氧化的影响

硒与心血管的结构、功能及其疾病的发生关系密切。世界卫生组织和国际原子能协会已把硒列为与冠心病发病有关的５种元素之一而加以研究。近年来 ,人们逐渐认识到脂质过氧化机理在动脉粥样硬化发生发展中的作用 ,体内血脂代谢异常及氧化损伤是动脉粥样硬化发生发展的重要原因。硒作为自由基清除剂在一定程度上 ,有调节血脂代谢及抗氧化的作用。饮食摄入一定量的硒和体内维持一定水平的硒 ,对防止高脂血症具有积极意义。扇贝提取物是以扇贝为原料提取制备的富含微量元素硒及多种微量元素、维生素和蛋白质等生理活性物质的富硒提取物。本研究利…     

Theoretical wind wave frequency spectra in deep water——Ⅰ. Form of spectrum

In this part ot the paper theoretical wind-wave spectra nave been derived oy (I) expressing the spectrum in series composed of exponential terms; (2) assuming that the spectrum satisfies a high order linear ordinary differential equation; (3) introducing proper parameters in the spectrum; and (4) making use of some known charateristics of wind-wave spectrum, for instance, the law governing the equilibrium range. The spectrum obtained contains the zero order moment of the spectrum m0, the peak frequency ω0 and the ratio R =ω/ω0 (ω being the mean zero-crossing frequency) as parameters. The shape of the nondimensional spectrum S(ω) = ω0S(ω)/m0(ω=ω/ω0) changes with R and theoretically reduces to a Dirac delta function δ(ω-1) when R = 1. A spectrum of simplified form is given for practical uses, in which R is replaced by a peakness factor P=S(1).     

伶仃洋L＿2和L＿（16）孔第四纪有孔虫群与孢粉化石带特征及其地质意义

本文所依据的分析样品是取自珠江最大的一个河口湾伶仃洋中部的水下钻孔岩芯，其底部到达花岗岩基底。通过对第四纪有孔虫群与孢粉化石带特征的分析，阐明在相同的钻孔岩芯中，有孔虫分布变化所反映的古沉积环境特征与孢粉分析的古气候特征较为吻合，并与相应的沉积相对应，结合￣（１４）Ｃ和￣（２３０）Ｔｈ／￣（２３２）Ｔｈ比值法测年数据，从而较好地重塑本区晚更新世中期以来的地质历史。     

空间扰动引力的谱分析

基于重力场的频谱理论，给出了扰动引力在全球平均意义下的功率谱表达式，揭示了扰动引力的传播特性。通过数值试验，给出了扰动引力随高度变化规律，并分析了不同高度上，扰动引力恢复重力场的最高阶数及相应分辨率。从理论上分析了航空重力测量探测重力场中高频信息的能力，对制定飞行方案有一定参考价值。     

Analytic Solution of Interaction Between Surface Waves and Floating Elastic Plates with Elastic End-Restraints

Based on the dynamic theories of water waves and Mindlin plates,the analytic solution of interaction between surface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique.Firstly,without regard for elastic edge restraint,the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results.Therefore,it can be shown that the present method is valid.Secondly,three end-restraint cases(i.e.,the left-end elastic restraints,the both-end elastic restraints,and the right-end elastic restraints)are proposed to reduce the vibration of floating plates,in which the spring is used to connect the sea bottom and the floating plate's left(or right)edge.The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed.Moreover,the effective method to reduce the vibration of floating elastic plates can be obtained through comparison.