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61.
本文介绍了国家标准《潜水员水下用电安全技术规范》的研究、编制过程,以及编者对该标准性质、适用范围、总体结构、电气安全数值取舍等的基本认识,并就该标准制定实施后的经济、社会效益进行了初步预测。 相似文献
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Bulk particulate organic carbon in the East China Sea: Tidal influence and bottom transport 总被引:4,自引:0,他引:4
Five oceanographic surveys were carried out in the East China Sea (ECS) and Yellow Sea from 1999 to 2003. In all, seven different sections were surveyed, but one section (the PN section) was observed on every cruise. Two time-series stations were also surveyed, one located at the Changjiang River mouth, the other over the continental shelf in the PN section.We identified biogeochemical characteristics for waters close to the Changjiang Estuary and in the Kuroshio waters (KW), respectively. Resuspension is a strong feature near bottom over the ECS continental shelf, with suspended matter values 13 times higher than that for the surface. A model of particulate organic carbon (POC) dynamics based on a rectangle equation reveals that POC concentration close to the Changjiang Estuary varies with a semidiurnal period of ∼13 h, coinciding with the tidal period. The upper limit for POC residence times in the seasons we covered over the shelf are estimated to be on the order of weeks and generally increase seaward from near the Changjiang Estuary to the KW. Short POC residence times suggest that POC in the ECS is rapidly exported from euphotic waters.A nepheloid layer, observed as elevated suspended matter in near the bottom of the water column, is important in particle transfer over the shelf, especially in winter when the residual current flows mainly eastward. Cross-shelf transport of POC via the nepheloid layer is estimated to be 0.22 × 1012 g yr−1. Comparison with other work indicates that POC transport is ∼2% of the Changjiang POC input. 相似文献
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本文在对位于黄海南部陆架上的朝连岛站30年水温资料进行分析时发现,该站的表层水温有周期大于20个月的低频振动,其中以准两年周期和6年周期最显著。陆架水温的这种低频振动是对东亚季风异常的响应。这种低频振动在冬季与渤海冰情的变化同步;在夏季与黄海底层冷水团的强弱相关。同时,这种低频振动在对马暖流上也有一定的反映。 相似文献
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We study the problem of determination of the sound field of a point harmonic source in the coastal zone and the influence of a cylindrical body floating above the source on the sound field formed in the marine medium. A numerical-analytic method is proposed for the determination of the velocity potential. According to this method, the unknown coefficients in the general solution of the problem are determined from the corresponding infinite system of linear algebraic equations by the method of reduction. We present results of numerical calculations for a special case of a waveguide whose parameters are typical of the coastal part of the sea and perform the comparative analysis of the data obtained as a result of variation of the indicated parameters. 相似文献
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In the food clods of the mass species of macrobenthos of the Gryaznaya Inlet, nonstructured matter plays a great role. We identify this matter as derivates from plant tissues, which are the products of their external metabolism and degradation, with associated microorganisms. This way, the near-shore community considered is supported by a detrital trophic web. This feature distinguishes it from the similar community of the near-Atlantic waters that is based on a pasture web, at least as far as the bivalve mass species are concerned. The groups of the near-shore species of Gryaznaya Inlet separated by a cluster analysis are identified as consortia, combined by the biogeochemical conditions (edifice factor), which can hardly be analyzed at present. 相似文献
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The basic properties of the dynamic model of a turbulent jet formed by a deep-water sewage discharge into the stratified environment of coastal regions are considered. The model developed was used to estimate the parameters of a floating-up jet of deep wastewater discharge from Sand Island into the basin of Mamala Bay (Hawaii) depending on the season and discharge operation mode. The estimates of the float-up depths of the jet and the initial dilution of the jet were estimated on the basis of model calculations using experimental data on the vertical profiles of the water temperature and salinity under the actual conditions of stratification in the study region. It is shown that the further propagation of the wastewater jet depends on tidal events and internal waves generated by tides. The appearance of turbulent jets at the sea surface was recorded. The model estimates of the parameters of the wastewater discharge were compared with the results of experimental measurements. Good agreement was found, which indicates that the physical mechanisms of the propagation of turbulent jets in a stratified medium are adequately described by the model. 相似文献
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为了评价海洋水色卫星遥感器特性参数的优劣,确定仪器的计量特性及其使用价值,准确的理解和科学的定义仪器的特性参数是非常重要的。作者曾有幸参加了海洋水色卫星的立项论证工作,本文就作者的一些工作体会,对海洋水色卫星遥感器的特性参数作初步探讨。 相似文献