共查询到20条相似文献，搜索用时 156 毫秒
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分析海浪方向谱的扩展本征矢方法：I.方法的导出 总被引：5，自引：0，他引：5
基于交叉谱矩阵可以按本征值划分为信号和含有噪音部分的思想，提出了一种自直接测量数据估计海浪方向谱的方法。该方法称为扩展本征矢方法（ＥＥＶ），应用于单点测量系统，仪器阵列以及由地者构成的复合阵列。现有的某些估计方法（如最大似然方法及其扩展形式等）仅是此方法的某种特例。 相似文献
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《海洋学报(英文版)》1995,(3)
ＥＤＩＴＯＲＩＡＬＣＯＭＭＩＴＴＥＥ￥／／ＡｄｖｉｓｅｒｓＣｈｅｎ￣ｎ（ＣｈｅｎＫ￣ｃｈｅｎｒｅＭ￥）ＴａＤＳｈｉｐｏｎ（Ｎ＃ｇ）ｆｂｉＡｎｂｏｎｓ（ｔ￥＃）ｗａｎｇ￣ｏ（ｗａｎｇＴｅ－ｃｉａＥ￥Ｂ）ＬｉｎＢｉｄｄｅｎ（ＬｉｎＰｉｎｇ－ｎａｍ＃＊Ｗ）... 相似文献
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多年用海底压力式验潮仪的研制（英国Ｐｒｏｕｄｍａｎ海洋研究所，ＰＯＬ，Ｂｉｄｓｏｎ观测站Ｒ．ＳＰｅｎｃｅｒ，Ｐ．Ｒ．Ｆｏｄｅｎ，Ｃ．ＭｃＧａｒｒｙ，Ｊ．Ｍ．Ｖａｓｓｉｅ）１引言ＰＯＬ技术研究方案的一部分是ＭＹＲＴＩＥ（重现多年潮位的设备ＭｕｌｔｉＹｅ... 相似文献
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ＪＢ－１型交流磁场退磁仪的研制ＤＥＶＥＬＯＰＭＥＮＴＯＦＪＢ┐１ＴＹＰＥＤＥＭＡＧＮＥＴＩＺＥＲＯＦＡＣＭＡＧＮＥＴＩＣＦＩＥＬＤ交流磁场退磁仪是当前第四纪地质、环境地质及其它地质矿产领域中古地磁及岩石磁学研究的主要测试设备之一，它主要是用来对地质标... 相似文献
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约翰斯顿岛附近海域铁锰结壳矿物学和地球化学研究 总被引：11，自引：4，他引：11
铁锰结壳存在两种不同的产状，一种是铁锰氧化和的围绕“核心”生长形成的球状结壳，另一种是铁锰氧化物在基底岩石上生长形成的被状结壳。本文对Ｒ／Ｖ，Ｋａｉｍｉｋａｉ－Ｏ－Ｋａｎａｌｏａ船１９９３年１１月在约翰期顿岛附近海域取得铁锰结壳进行了矿物学和地球化学分析。该区铁锰结壳主要组成矿物为δ－ＭｎＯ２，Ｍｎ／Ｆｅ比值为２．０２，富Ｃｏ（０．８８１％），盆Ｃｕ（０．１％），稀土总量（∑ＲＥＥ）１９１８．２７ 相似文献
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刘树臣 《海洋地质与第四纪地质》1994,(3)
我国环境地质状况及值得重视的若干问题ＳＩＴＵＡＴＩＯＮＳＯＦＣＨＩＮＡ＇ＳＥＮＶＩＲＯＮＭＥＮＴＡＬＧＥＯＬＯＧＹＡＮＤＳＯＭＥＰＲＯＢＬＥＭＳＴＨＡＴＭＥＲＩＴＡＴＴＥＮＴＩＯＮＳ我国人口众多，地质条件复杂，各种环境地质和灾害地质问题极为突出和严重... 相似文献
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文章得到相建海、董金海以及邓景耀、李德尚、罗秉 征、唐启升、周名江研究员书面或口头上的帮助，在 此诚表谢意。 中国科学院海洋研究所调查研究报告第２９３５号。ＴＨＥ ＡＰＰＬＩＣＡＴＩＯＮＳ ＯＦ ＳＹＳＴＥＭ ＡＮＡＬＹＳＩＳ ＭＥＴＨＯＤＳ ＩＮ ＦＩＳＨＥＲＹＲＥＳＯＵＲＣＥＳ ＳＴＵＤＹ ＡＮＤ ＥＣＯＬＯＧＩＣＡＬ ＥＮＶＩＲＯＭＥＮＴＡＬ ＥＮＧＩ－ＮＥＥＲＩＮＧ 系统理论与系统分析应用于渔业资源、生态环境工程始于６０年代，现已成为定量研究渔业资源、生态环境工程必不可少的工具之一，并已为大家普遍接受。… 相似文献
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《海洋地质与第四纪地质》1994,(2)
攀登海洋地质科学高峰──记李四光地质科学野外地质工作奖获得者王光宇教授的科学事迹ＡＭＡＮＤＥＶＯＴＥＤＨＩＭＳＥＬＦＴＯＭＡＲＩＮＥＧＥＯＬＯＧＩＣＡＬＳＸＩＥＮＣＥ地矿部广州海洋地质调查局王光宇教授，１９９３年１０月喜获第三届李四光地质科学野外地质... 相似文献
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研究了青岛市南、市北、四方三区交警在服用排铅奶粉（ＬｅａｄＥｘｃｒｅｔｉｎｇＭｉｌｋＰｏｗ－ｄｅｒ，ＬＥＭＰ）前后，体内粪铅含量变化情况。实验结果表明，服用ＬＥＭＰ后，粪铅含量先呈上升趋势，达到最高值后，又呈下降趋势。在整个实验过程中，粪铅含量四方区最高，而市南区最低。服用ＬＥＭＰ前，三区交警粪铅平均含量为０．６８７ｍｇ／ｋｇ，服用７ｄ后达到峰值（１．９６ｍｇ／ｋｇ，Ｐ＜０．０１），第１５ｄ降到１．６１（ｍｇ／ｋｇ）（Ｐ＜０．０５），表明ＬＥＭＰ能排除体内铅起到预防铅中毒的作用 相似文献
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管长龙 《中国海洋大学学报(自然科学版)》1996,(1)
将Pawka为改进最大似然方法（MLM）而提出的迭代方案应用于扩展本征关方法（EEV），作为EEV的一种迭代形式（IEEV）。用模拟数据检验了IEEV的合理性，并与EEV作了比较。计算结果表明，IEEV的估计性状较EEV有改善。最后将IEEV及EEV用于分析仪器阵列的外海观测数据。 相似文献
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Okey Nwogu 《Applied Ocean Research》1989,11(4):176-182
A procedure for estimating directional wave spectra from an array of wave probes based on the Maximum Entropy Method (MEM) is developed in the present paper. The MEM approach yields an angular spreading function at each frequency band consistent with the input cross-spectral density matrix. The method is evaluated using numerical simulations of directional sea states. The MEM is also used to analyze data obtained from the three-dimensional wave basin of the Hydraulics Laboratory, National Research Council of Canada. Finally, the MEM is compared with the Maximum Likelihood Method (MLM) and is shown to be a powerful tool for directional wave analysis. 相似文献
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海浪方向谱的现场观测与分析 总被引：3，自引：0，他引：3
方向谱是海浪的基本性质之一。本文在国内首次采用测波仪阵列法在渤海采油平台上成功地观测到海浪方向谱，给出了当地随波浪成长而变化的方向谱表达式。观测前采用数模和模型试验方法，对阵列的布置型式、测波仪间距和平台等对观测结果的影响，以及现有各种方向谱分析方法的精度等进行了对比分析，为提高观测精度，保证方向谱分析的质量提供了依据。 相似文献
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In the nearshore,the wave field contains reflected and incident waves in which there iscorrelation between their phases due to the effect of reflection by some obstacles.Based on the extendedeigenvector method(EEV)derived by Guan et al.,a modified method(MEEV)is proposed as a generaland practical approach to estimating directional spectra for the co-existent field of incident and reflectedwaves and a formula is given for direct calculation of the reflection coefficient.The results of numericalsimulations show that MEEV is superior to EEV in resolution power,and the computed reflectioncoefficient agrees well with the real value within a certain range of incident angle. 相似文献
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The observation and estimation of directional spectra of sea waves is one of the essential subjects of study of oceanic dynamics. On the basis of the irregular linear wave theory, estimation methods for i/UV, PUV and VV directional wave spectra are derived. By using ij and PUV data measured in-situ, directional wave spectra are estimated, meanwhile the virtues and defects of various spectra are comparied. This method provide a basis for the observations of sea waves. 相似文献
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This is a Part II of a paper of nonlinearities of wind waves in the deep open ocean. As shown in Part I, bound waves in deep sea are detectable by extracting secondorder Doppler spectra from the Doppler spectra of HF (high-frequency) radio waves scattered from the sea surface. There is a remarkable agreement between the calculated and measured Doppler spectra, considering the noise levels in measured Doppler spectra and the uncertainties in directional properties. The theoretical expression for bound waves is thus verified. Furthermore, the upper limit in calculating the Doppler spectra for the second-order approximation is presented from field observations, although we cannot conclude that it is equivalent to the limitation of the second-order bound wave theory. It is shown that analysis of radio wave scattering by the sea surface is one useful means of understanding the nonlinear properties of ocean waves. 相似文献
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The detailed reconstruction of the directional spectrum of wind waves from measurements of the wave field is an essential requirement for several applications, including the numerical modeling of wave evolution. Three reconstruction techniques that provide estimates of the directional distribution function D(f,θ), given the one-dimensional frequency spectrum, are compared using data from a coastal locality at the southern Brazilian coast. The techniques are the maximum entropy method (MEM), the Fourier Expansion Method using a cos2 type function (FEMcos) and the Fourier Expansion Method using a sech type function (FEMsech). The main patterns of the wave climate at the study site are qualitatively assessed. Three main sea states, including swell, transition between local sea and swell, and directionally bimodal wind sea, are identified. Time series from three events associated with the main sea states provide test cases for inter comparison of the three reconstruction techniques. Maximum entropy estimates of D(f,θ) provide results that are more consistent than those obtained from the two FEM techniques in all cases considered. 相似文献
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In traditional spectral analysis the use of windows is required because the assumption is made that the data outside the sample are zero. A data window is simply equal to unity inside, and zero outside the sample. This is equivalent to the truncation of the autocovariance function beyond some lag after which zeros are added. In Fast Fourier Transform spectral estimation a spectral window with smaller or greater negative side lobes is used. Any use of windows results in a smearing or spectral leakage that limits the spectral resolution. Maximum entropy spectral estimation (MEM) is equivalent to an extrapolation of the autocovariance function being consistent with some model assumptions. The result of the extrapolation is an increased spectral resolution in the frequency domain. In applications of MEM no kind of windows are used. MEM is applied to describe wind wave scalar spectra. The technique can also be used in the plane to estimate directional spectra. Our results show that MEM is a powerful tool for estimation of scalar spectra and simulation of the sea surface. There are also theoretical reasons for assuming that MEM are superior to traditional methods when only short samples are available. Our preliminary results verify this assumption. We propose a data acquisition system based on MEM, and also show that the response of linear systems can be calculated and simulated by MEM. 相似文献
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Liu Shuxue Yu Yuxiu
Assistant Researcher State Key Laboratory of Coastal Offshore Engineering Dalian University of Technology 《中国海洋工程》1995,(1)
The directional spectrum is one of the basic characteristics of sea waves. The observations of directional spectrum of sea waves were successfully conducted at platform Bohai 8 during 1991 and 1992 using a wave gage array for the first time in China. Based on the field data, the directional spectrum which depends on the wave growth is given in this paper. Before observations, the effects of the type of gage array, the distance between the gages and the platform itself on the measured results and the precision of some methods for estimating the directional spectrum were investigated and compared with the methods of numerical simulations and model tests of multi-direcitonal irregular waves. This ensures the quality of the observations and estimations of the directional spectrum. 相似文献