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121.
122.
Based on the ray theory and Longuet-Higgins’s linear model of sea waves, the joint distribution of wave envelope and apparent wave number vector is established. From the joint distribution, we define a new concept, namely the outer wave number spectrum, to describe the outer characteristics of ocean waves. The analytical form of the outer wave number spectrum, the probability distributions of the apparent wave number vector and its components are then derived. The outer wave number spectrum is compared with the inner wave number spectrum for the average status of wind-wave development corresponding to a peakness factor P = 3. Discussions on the similarity and difference between the outer wave number spectrum and inner one are also presented in the paper.  相似文献   
123.
A simple and effective method of heating divers in extreme cold water has been developed. The local heating concept utilizes a uniformly distributed granular mixture of magnesium and iron particles packed in small sachets. Upon activation by sea water, the two metal mixture behaves as a multitude of short-circuited electrolytic cells, producing thermal energy rather than electrical energy. The 45 mm-square sachets may be placed where heating is required on the diver's body, thus giving rise to the term “local heating”, obviously, the heating system requires no pumping device, or distribution network. Heating rate and duration of output of the sachets are controlled by particle size, and mixture ratio of the constituent Mg and Fe particles.This paper described the development, testing and performance of the heating sachets. Results of live tests in different dive situations are also presented and discussed.  相似文献   
124.
Physical properties, sound velocity and density of 95 core samples from ten locations along a transect (parallel to 15°N latitude) across the Bay of Bengal were measured. Results indicate that sound velocities range from 1,482 to 1,679 m/s (av: 1,583 m/s) and densities from 1,338 to 1,757 kg/m3 (av: 1,527 kg/m3). It has been observed that dark colored clays and sandy clays show higher values of sound velocity and density than the average values. A comparative study of the same with that of the sediment cores collected from the Norwegian basin, Mediterranean Sea, and Hatteras, Nares Abyssal plains, western North Atlantic Ocean was done.  相似文献   
125.
Short period internal waves over the Huanghe (Yellow River) delta front   总被引:4,自引:0,他引:4  
Internal waves with periods of about 5 minutes and trough to crest heights of up to 6.2 m were observed acoustically over the actively accreting delta front of the Huanghe (Yellow River) in the western portion of the Gulf of Bohai, Peoples Republic of China. The radian frequency of the internal waves was close to the locally-observed Brunt-Vaisala frequency. Through the relatively short (one hour) duration of an internal wave train, the amplitude was observed to decrease progressively with time. These internal waves may cause resuspension of delta-front sediments.  相似文献   
126.
藤壶属(Genus Balanus)是甲壳类蔓足亚纲(Subclass Cirripedia)藤壶科(Family Balanidae)中最大的一属,它在有害海洋附着生物中是主要组成成分。许多种附着于船底、水下设施或建筑物上,致使船舰燃料消耗增加,航速减低,降低浮标浮力,缩小管道通路,侵占某些水产养殖对象的有效附着面,污损养殖架筏和绳索,加快水下金属的腐蚀等,对海防、海运交通、工业和渔业常造成一定危害,同人类的关系颇为密切。随着我国科学事业的发展,特别是附着生物防除工作的进展,对于种类的确切鉴定和生物学及生态学资料需要日益增多,只有在搞清种类的基础上,根据不同种的生物学和生态特征,采取相应的措施,才能有效地进行防除工作。 中国近海的藤壶属,国内外仅有一些零星记载,缺乏全面而系统的报告。我们早在五十年代,就注意到我国沿海常见的一些主要附着生物,特别是当时作为“布纹藤壶” Balanus Amphitrite communis Darwin(=B.reticulatus Utinomi)和“克氏藤壶”Balanus Amphitrite krügeri Nilsson-Cantell(=B.uliginosus Utinomi)描记的两个类型,无论在栖息环境、繁殖习性或幼虫形态上都有显著差异,因而怀疑它们不是一个种内的亚种,而应属于不同的种。为了解决上述和类似的问题,给生态和防除研究工作提供更为准确的基本资料,我们对藤壶亚目的种类进行了系统的研究,本文是研究报告的第一部分。根据的是中国科学院海洋研究所历年采集收藏的标本,共鉴定31种和亚种,分隶于7个亚属,其中有6新种,有9种在我国是首次记录(种名录见190页)。新种的模式标本均保存于中国科学院海洋研究所。  相似文献   
127.
Dissolved and particulate manganese in seawater samples derived from the English Channel has been analyzed using graphite furnace atomic absorption (GFAAS), and inductively coupled plasma atomic emission (ICP—AES) spectroscopies. Because of the high contents of carbonate minerals found in the suspended matter samples, the English Channel constitutes an ideal field area for the study of the Mn2+/Ca2+/CaCO3 system. Owing to the chemical speciation of particulate manganese and the combined use of the X-ray diffraction and electron spin resonance spectroscopy we have shown the importance of the carbonate phase in the stabilization of manganese (II). This has been confirmed by p-pH measurements in the field. All these studies have also indicated that: (1) manganese is associated with calcite in the form of a solid solution, MnxCa1−xCO3; and (2) significant increases in the concentrations of particulate manganese, especially in offshore waters, occur in summer. This seasonal phenomenon has been attributed to the proliferation of coccolithophorids, which are known to be covered with calcified skeletons at high specific surface areas. To appraise the implication of the coccolithophorid-blooms phenomenon on the Mn2+/Ca2+/CaCO3 system, we have used the manganese distribution coefficient, Di, between the liquid phase and CaCO3 particles. Overall we have shown that: (1) Di in summer (i.e. when coccoliths considered as very fine-grained calcite are abundant) is much higher than that obtained in winter; and (2) in the vicinity of the French coast, Di does not vary significantly even in summer. This is because of the high content of chalk-derived particles found in the near-shore waters.  相似文献   
128.
三峡工程对长江口区无脊椎动物资源影响的预测   总被引:1,自引:0,他引:1  
长江大量径流给其河口及邻近海域带来丰富的营养物质,维持了长江河口生态系统的巨大生产力,并使之成为多种重要经济鱼虾类的索饵和产卵场。长江口生态环境的变化,对我国最大、最重要的浙江舟山渔场和江苏吕四渔场的渔业资源有举足轻重的影响。三峡工程的兴建将使长江入海径流量及其季节分配有很大改变,也不可避免地影响到河口和近海的海洋环境、经济动物的组成及资源状况。为研究长江口无脊椎动物资源结构及其分布特征,以及预测三峡工程对自然生态环境的影响,于1985年9月至1986年8月进行了无脊椎动物资源底拖网试捕调查。本文系统整理调查所得资料,结合历史资料进行分析研究。  相似文献   
129.
Despite the fact that BaP is a carcinogen, mammalian immunosuppressant, and ubiquitous aquatic pollutant, knowledge regarding the effects of BaP on the immune system of fish is still lacking. To begin to fill this gap, studies were conducted in medaka to examine the effects and mechanisms by which BaP exposure might alter host immunocompetence. Fish, exposed by IP injection of BaP (2-600 microg/g BW), were examined after 48 h for effects upon immune function and CYP1A expression/activity. Benzo[a]pyrene, at a concentration below that which increased levels of CYPIA expression/activity (2 microg BaP/g BW) suppressed lymphocyte proliferation. Concentrations of BaP at 20 and 200 microg/g BW. suppressed antibody-forming cell (AFC) numbers, superoxide production, and host resistance against bacteria. In contrast, exposure to the low affinity aryl hydrocarbon receptor (AhR) agonist, benzo[e]pyrene (BeP), neither induced CYP1A expression nor altered immune function. Given the lack of immunosuppressive effects produced by BeP, and the fact that exposure to the AhR antagonist (and CYP1A inhibitor) alpha-naphthoflavone (ANF) ameliorated the suppressive effects of BaP upon AFC numbers, the AhR pathway (including CYP1A-mediated production of reactive BaP metabolites) appears important in mediating BaP-induced immunotoxicity in fish, as in mammals. In the past, the medaka has proven a successful model for assessing carcinogenic agents. These studies have demonstrated its utility for also determining the immunosuppressive effects of an important aquatic contaminant.  相似文献   
130.
Izvestiya, Atmospheric and Oceanic Physics - This paper summarizes the results of long-term (2004–2016) comprehensive experimental studies of microphysical parameters and the mass...  相似文献   
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