Comparing the Benguela and Humboldt marine upwelling ecosystems with indicators derived from inter-calibrated models   总被引：10，自引：0，他引：10  

Moloney  Coleen L.; Jarre  Astrid; Arancibia  Hugo; Bozec  Yves-Marie; Neira  Sergio; Roux  Jean-Paul; Shannon  Lynne J. 《ICES Journal of Marine Science》2005,62(3):493-502

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Combining indicator trends to assess ongoing changes in exploited fish communities: diagnostic of communities off the coasts of France   总被引：1，自引：1，他引：1  

Rochet  Marie-Joelle; Trenkel  Verena; Bellail  Robert; Coppin  Franck; Le Pape  Olivier; Mahe  Jean-Claude; Morin  Jocelyne; Poulard  Jean-Charles; Schlaich  Ivan; Souplet  Arnauld; Verin  Yves; Bertrand  Jacques 《ICES Journal of Marine Science》2005,62(8):1647-1664

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海坛海峡二维潮流场数值模拟   总被引：2，自引：0，他引：2  

汤军健  温生辉  陈楚汉 《台湾海峡》2006,25(4):533-540

海坛海峡为南北狭长型海峡，海峡内潮波属于前进波．本文建立了平面二维浅水波数学方程，利用欧拉-拉格朗日差分方法得到数值解，模型采用随时间变化的动边界技术，成功地模拟了海坛海峡的前进波特征，并根据实测数据进行了验证．同时计算了同潮时线和等振幅线，不同时刻的潮流场和潮流平均流速分布．计算结果表明，北部湾口M2分潮高潮时间比南部湾口早约5～6min，等振幅线范围约为2．12～2．15m．海峡内流速分布呈南北强、中间弱的特点，最大流速1m／s左右．  相似文献   

A new approach for the solution of the two-dimensional guillotine-cutting problem in ship production     

A. Cemil Dikili 《Ocean Engineering》2004,31(8-9):1193-1203

A new approach has been developed for the arrangement of rectangular pieces in plates for the guillotine-cutting problem as encountered in ship production and similar manufacturing processes. The algorithm is quite novel in the sense that instead of making preliminary specifications and ignoring all the alternative arrangements, as is the case for most of the current models, it selectively considers feasible arrangements by eliminating the majority of the probable arrangements that render the problem insolvable. Intermediate steps of the algorithm produce results which cannot be obtained through integer programming. Losses are distributed to the minimum number of plates. The number of arrangement plans is also minimized. Overall the solution of the problem has been drastically simplified to allow even hand calculations instead of long computer runs.  相似文献   

Monotone Regression and Correction for Order Relation Deviations in Indicator Kriging     

韩燕  杨毅恒 《中国地质大学学报(英文版)》2008,19(1):93-96

The indicator kriging (IK) is one of the most efficient nonparametric methods in geo-statistics. The order relation problem in the conditional cumulative distribution values obtained by IK is the most severe drawback of it. The correction of order relation deviations is an essential and important part of IK approach. A monotone regression was proposed as a new correction method which could minimize the deviation from original quintiles value, although, ensuring all order relations.  相似文献   

论氢化物的形成及其在分析测试领域的应用          下载免费PDF全文

郑大中  王惠萍  郑若锋 《江苏地质》2008,32(1):5-11

论述了氢化物形成的普遍性、氢化物的物理化学性质、元素周期系各类元素的氢化物类型。认为一些金属离子、非金属离子在酸性介质中与硼氢化钾（钠）作用及金属锌等强还原剂作用生成氢化物。综述了氢化物的形成在分析测试领域的应用：试样分解、分离富集、容量分析、光度分析、原子光谱分析、质谱分析。  相似文献   

The Bayesian detection of discontinuities in a polynomial regression and its application to the cycle-slip problem   总被引：4，自引：1，他引：3  

Maria Clara de Lacy  Mirko Reguzzoni  Fernando Sansò  Giovanna Venuti 《Journal of Geodesy》2008,82(9):527-542

This paper deals with the problem of detecting and correcting cycle-slips in Global Navigation Satellite System (GNSS) phase data by exploiting the Bayesian theory. The method is here applied to undifferenced observations, because repairing cycle-slips already at this stage could be a useful pre-processing tool, especially for a network of permanent GNSS stations. If a dual frequency receiver is available, the cycle-slips can be easily detected by combining two phase observations or phase and range observations from a single satellite to a single receiver. These combinations, expressed in a distance unit form, are completely free from the geometry and depend only on the ionospheric effect, on the electronic biases and on the initial integer ambiguities; since these terms are expected to be smooth in time, at least in a short period, a cycle-slip in one or both the two carriers can be modelled as a discontinuity in a polynomial regression. The proposed method consists in applying the Bayesian theory to compute the marginal posterior distribution of the discontinuity epoch and to detect it as a maximum a posteriori (MAP) in a very accurate way. Concerning the cycle-slip correction, a couple of simultaneous integer slips in the two carriers is chosen by maximazing the conditional posterior distribution of the discontinuity amplitude given the detected epoch. Numerical experiments on simulated and real data show that the discontinuities with an amplitude 2 or 3 times larger than the noise standard deviation are successfully identified. This means that the Bayesian approach is able to detect and correct cycle-slips using undifferenced GNSS observations even if the slip occurs by one cycle. A comparison with the scientific software BERNESE 5.0 confirms the good performance of the proposed method, especially when data sampled at high frequency (e.g. every 1 s or every 5 s) are available.  相似文献   

利用参考重力场模型基于能量法确定GRACE加速度计校准参数   总被引：1，自引：0，他引：1  

徐新禹  李建成  王正涛  邹贤才 《武汉大学学报(信息科学版)》2008,33(1):72-75

利用多个参考重力场模型分别对GRACE一个月的实测加速度计观测数据进行检校.数值计算结果的比较分析表明了利用参考重力场模型确定加速度计校准参数是有效的.  相似文献   

Strain localization due to structural in-homogeneities in the Central European Basin System     

Mauro Cacace  Ulf Bayer  Anna Maria Marotta 《International Journal of Earth Sciences》2008,97(5):899-913

The large-scale crustal deformations observed in the Central European Basin System (CEBS) are the result of the interplay between several controlling factors, among which lateral rheological heterogeneities play a key role. We present a finite-element integral thin sheet model of stress and strain distribution within the CEBS. Unlike many previous models, this study is based on thermo-mechanical data to quantify the impact of lateral contrasts on the tectonic deformation. Elasto-plastic material behaviour is used for both the mantle and the crust, and the effects of the sedimentary fill are also investigated. The consistency of model results is ensured through comparisons with observed data. The results resemble the present-day dynamics and kinematics when: (1) a weak granite-like lower crust below the Elbe Fault System is modelled in contrast to a stronger lower crust in the area extending north of the Elbe Line throughout the Baltic region; and (2) a transition domain in the upper mantle is considered between the shallow mantle of the Variscan domain and the deep mantle beneath the East European Craton (EEC), extending from the Elbe Line in the south till the Tornquist Zone. The strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the CEBS.  相似文献   

A spectrophotometric measurement of soil cation exchange capacity based on cobaltihexamine chloride absorbance     

Delphine Aran  Armand Maul  Jean-Franois Masfaraud 《Comptes Rendus Geoscience》2008,340(12):865-871

Among numerous methods for cation exchange capacity (CEC) determination for soils and sediments, the cobaltihexamine chloride method is frequently used due to its ability to measure CEC at soil pH. After exchange with Co(NH₃)₆³⁺ ions, CEC is estimated via the measurement of the Co remaining in solution. The modified method proposed allows a more rapid determination of CEC based on the measurement of the absorbance at 472 nm of the cobaltihexamine chloride solution before and after exchange. This method has been applied to various soil's horizons from four sites, selected to cover a wide range of CEC and pH values. The model obtained allows one to calculate CEC from absorbance at 472 nm with 95% confidence intervals. As CEC is of relevant meaning in agronomical and environmental purposes, and more recently in ecotoxicological studies, this modified method can be proposed as a rapid test for CEC evaluation.  相似文献