利用TGO软件的点校正功能实现物探测量GPS控制网待定点的解算     

阮孝福  舒川  张梦 《北京测绘》2009,(4):75-77,45

基于泌阳凹陷高精度三维地震采集测量GPS控制测量项目，作者论述了在TGO软件中利用点校正功能求解控制网中待定点坐标方法。通过与约束平差结果的比较，证明了此方法的可行性。  相似文献   

RTK技术在南阳市全国土地二次调查中的应用     

张凯  马书英 《北京测绘》2009,(3):45-47

实时动态（Real Time Kinematic）测量技术，简称RTK技术已风靡全球，它具有全球、全天候工作、定位精度高等优点，在当今测绘界已经得到广泛应用。RTK技术在南阳市全国土地二次调查中起到了关键的作用，大大提高了工程进度，降低了成本。  相似文献   

Temporal distributions of anthropogenic Al,Zn and Pb in Hong Kong Porites coral during the last two centuries     

《Marine pollution bulletin》2012,64(5-12):508-515

A 182-year long record of trace metal concentrations of aluminum, zinc and lead was reconstructed from a massive Porites coral skeleton from southeastern Hong Kong to evaluate the impacts of anthropogenic activity on the marine environment. Zn/Ca and Pb/Ca ratios fluctuate synchronously from the early 19th century to the present, indicating that the marine environment has been anthropogenically influenced since industrialization. Additionally, land reclamation, mining, and ship building activities are recorded by elevated Al/Ca ratios from 1900 to 1950. The coral record indicates that high levels of Zn, Pb and Al occur coincidentally with local wars, and may have contributed to partial colony mortality. Pb/Ca does not correlate well with hemispheric proxy records after 1950, indicating that coastal corals may be recording local rather than hemispheric contamination. Pb/Ca levels in Hong Kong, Guangdong and Hainan corals imply a continuous supply of Pb-based contamination to southern China not reflected in hemispheric signals.  相似文献   

An analysis of the employment durations of UK seafaring officers 1999     

《Marine Policy》2001,25(4):293-301

This paper presents the results of an analysis of the duration of voyages undertaken by National Union of Marine Aviation Shipping Transport (NUMAST) deck and engineer officers during 1998–99. It provides a snapshot of the employment profile of the officers, and compares voyage patterns across Organisation Type, Company Nationality, Flag of Registry, and Ship Type.Analysis of the various cross-tabulations of employment duration appears to show that the key driver is ship type, which it is argued, is a proxy for different markets, which have different employment requirements for its seafarers. Further work is needed to determine the factors which help to explain the observed variations in voyage durations.The paper is completed with an analysis of the age profiles of NUMAST officers by Flag of Registry. It is shown that significant variations in age profiles exist, with those working under Open registers being slightly older than those in the UK or UK related registers.  相似文献   

Fisheries property rights and recreational/commercial conflict: implications of policy developments in Australia and New Zealand     

《Marine Policy》2001,25(1):49-59

Commercial fisheries management in Australia and New Zealand is increasingly based on better definition of the rights and responsibilities of resource users. At the same time recreational fishers are claiming a greater share of resources largely based on perceptions of superior economic returns to the community from their activities. The basis of the conflict between traditional, recreational and commercial resource users is moving from physical competition for fish to economic and legal arguments over social priorities. Advantages and disadvantages of increased use of property rights in resource allocation are investigated. It is argued that the recreational sector needs better definition of its claim for priority access to resources.  相似文献   

Distribution and sources of heavy metals in the sediment of Xiangshan Bay   总被引：2，自引：0，他引：2  

SUN Weiping  YU Jianjun  XU Xiaoqun  ZHANG Weiyan  LIU Ruijuan  PAN Jianming 《海洋学报(英文版)》2014,33(4):101-107

Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry(ICP–MS) in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sediments of the bay have been generally influenced by anthropogenic inputs since the founding of the People's Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrichment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of wastewater into the Bay should be restricted.  相似文献   

基于随机集合的非传统型有效波极值模型   总被引：1，自引：0，他引：1  

ZHANG Yi  LAM Jasmine Siu Lee 《海洋学报(英文版)》2014,33(7):125-130

The analysis and design of offshore structures necessitates the consideration of wave loads. Realistic modeling of wave loads is particularly important to ensure reliable performance of these structures. Among the available methods for the modeling of the extreme significant wave height on a statistical basis, the peak over threshold method has attracted most attention. This method employs Poisson process to character- ize time-varying properties in the parameters of an extreme value distribution. In this paper, the peak over threshold method is reviewed and extended to account for subjectivity in the modeling. The freedom in selecting the threshold and the time span to separate extremes from the original time series data is incorpo- rated as imprecision in the model. This leads to an extension from random variables to random sets in the probabilistic model for the extreme significant wave height. The extended model is also applied to different periods of the sampled data to evaluate the significance of the climatic conditions on the uncertainties of the parameters.  相似文献   

Numerical analysis and centrifuge modeling of shallow foundations   总被引：1，自引：0，他引：1  

罗强  栾茂田  杨蕴明  王忠涛  赵守正 《中国海洋工程》2014,28(2):163-180

The influence of non-coaxial constitutive model on predictions of dense sand behavior is investigated in this paper. The non-coaxial model with strain softening plasticity is applied into finite-element program ABAQUS, which is first used to predict the stress-strain behavior and the non-coaxial characteristic between the orientations of the principal stress and principal plastic strain rate in simple shear tests. The model is also used to predict load settlement responses and bearing capacity factors of shallow foundations. A series of centrifuge tests for shallow foundations on saturated dense sand are performed under drained conditions and the test results are compared with the corresponding numerical results. Various footing dimensions, depths of embedment, and footing shapes are considered in these tests. In view of the load settlement relationships, the stiffness of the load-displacement curves is significantly affected by the non-coaxial model compared with those predicted by the coaxial model, and a lower value of non-coaxial modulus gives a softer response. Considering the soil behavior at failure, the coaxial model predictions of bearing capacity factors are more advanced than those of centrifuge test results and the non-coaxial model results;besides, the non-coaxial model gives better predictions. The non-coaxial model predictions are closer to those of the centrifuge results when a proper non-coaxial plastic modulus is chosen.  相似文献   

浅基础地基荷载-变形特性的分析研究     

罗强  贾虎  栾茂田 《海洋工程》2014,32(4):72-81

在土体主应力方向的旋转过程中,主应力方向与塑性主应变增量方向之间存在着非共轴现象,非共轴现象对应力-应变关系具有显著的影响。通过有限元二次开发,将角点结构非共轴理论应用到有限元程序ABAQUS中;对密砂单剪试验进行数值模拟,研究了非共轴现象及其对应力-应变关系的影响;采用离心模型试验方法,对圆形浅基础作用下饱和密砂地基荷载-变形特性进行试验研究;对离心模型试验进行数值模拟,将试验结果与数值计算结果进行对比,对非共轴模型的计算结果的合理性进行验证。研究结果表明:非共轴现象对浅基础地基荷载-变形特性具有显著的影响;当选取合理的非共轴塑性模量时,非共轴模型的计算结果与离心模型试验结果比较接近。  相似文献   

Land of Strangers by Ash Amin. Polity Press,Cambridge, 2012, pp. v + 200 (ISBN 978‐0‐7456‐5217‐7) (hbk) (ISBN 978‐0‐7456‐5218‐4) (pbk).     

Laavanya Kathiravelu 《Singapore journal of tropical geography》2014,35(2):279-280

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