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1.
本文报道了以鲍鱼的上足分化幼虫和围口壳幼虫作试验对象，用土霉素、氯霉素、盐酸环丙沙星等抗菌药物作防治幼鲍病害的试验，结果表明：０．５～５ｇ／ｍ３浓度的氯霉素浸浴４８ｈ，１～１０ｇ／ｍ３浓度的土霉素浸浴４８ｈ，０．２５～０．５ｇ／ｍ３浓度的盐酸环丙沙星浸浴２４ｈ都能有效地抑制或杀死细菌；而幼鲍及饵料硅藻的生长和发育均不受其影响；但这些药物对原生动物、线虫和桡足类均无杀伤作用。 相似文献
2.
本文报道了以鲍鱼的上足分化幼虫和围口壳幼虫作试验对象，用土霉素、氯霉素、盐酸环丙沙星等抗菌药物作防治幼鲍病害的试验，结果表明：０．５￣５ｇ／ｍ＾３浓度的氯霉素浸浴４８ｈ，１￣１０ｇ／ｍ＾３浓度的土霉素浸浴４８ｈ，０．２５￣０．５ｇ／ｍ＾３浓度的盐酸环丙沙星浸浴２４ｈ都能有效地抑制或杀死细菌；而幼鲍及饵料硅藻的生长和发育均不受其影响；但这些物对原生动物、线虫和桡足类均无杀伤作用。 相似文献
3.
海水淡化方法很多,有蒸馏法、过滤法、冷却法等［５］。蒸馏法是用加热海水产生蒸汽再使之冷凝成水。过滤法是利用电渗析、反渗透技术进行海水淡化。该方法淡化海水耗能较大,理论能耗（最小值）为１．４ｋｗ·ｈ／ｔ,实际能耗大于１０ｋＷ·ｈ／ｔ。尽管随着反渗透膜性能的提高和海水淡化工艺的进步,使从海水中获取１ｍ３的淡水能耗下降到５．９ｋＷ·ｈ电,但是生产淡水的成本仍然高达１．６～２．２美元／ｔ［３］。因投资大和生产成本太高,这种技术尚难以大规模推广应用。我国中小型压汽蒸馏技术已进入成熟期,日产２０～５０ｍ３的… 相似文献
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介绍我校海洋环境学院物理海洋实验室刚建成的二号平台的主要性能。其主要性能：转速范围０．２～２５ｒ／ｍｉｎ；转速不均匀度小于０．３％，能在超低速（０．２～１ｒ／ｍｉｎ）下正常工作，转台平面度小于０．１ｍｍ／ｍ，集流环能够传输各种信号。专家会检验确认：该转台能满足地球流体动力学，海洋和大气环流等模拟实验研究工作的要求。 相似文献
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南麂列岛海域微小型底栖藻类生态研究 总被引：6，自引：0，他引：6
本文首次报道南麂列岛海域沉积物中的微型（２～２０μｍ）、小型（２０～２００μｍ）藻类组成、数量分布及其与环境因子的关系。经初步鉴定，沉积物中共有微小型藻类２４属７１种，其中小型的底栖圆筛藻属Ｃｏｓｃｉｎｏｄｉｓｃｕｓｓｐｐ．为２１种，广布于整个海区，春季平均细胞密度为（１０．４±３．６）×１０３个／ｃｍ２，占总密度的６５．４％；微型藻以中肋骨条藻Ｓｋｅｌｅｔｏｎｅｍａｃｏｓｔａｔｕｍ占优势，秋季平均细胞密度为（４２６２．８±１１９２８．２）×１０３个／ｃｍ２，占总细胞密度的９８．９％，主要分布在沿岸区。对０～１２ｃｍ柱状样品中细胞密度分层分析结果表明，０～２ｃｍ层的细胞密度大于２～５ｃｍ层大于５～１２ｃｍ层。沿岸区（１，２，５，６，７，８，９站）的种类和细胞密度高于岙口（３站）、远岸（１０站）及水道区（４站）。根据微小型底栖藻类组成特点，可划分为三个生态类群：广布性类群、暖水性类群和温带性类群。微小型底栖藻类密度与营养盐浓度的季节变化密切相关，秋季高于春季。 相似文献
6.
厦门黄厝文昌鱼保护区监测与研究 总被引：6，自引：2，他引：6
本文报道了１９９４年７月至１９９５年７月厦门黄厝文昌鱼自然保护区的监测结果。表明该区文昌鱼的数量较大，（平均密度１４２尾／ｍ＾２，平均生物量８．１０ｇ／ｍ＾２），体长组成以１１－４０ｍｍ为多，其性成熟主要在４月上、中旬，生殖期集中在４月下旬至５月上旬；文昌鱼栖息地义南类型以粗中砂为主，有机质含量较低，平均０．１４（ｍ／ｍ）；区内底栖生物５８种，种类以多毛类，软体动物和甲壳动物为主，数量则以棘皮动物 相似文献
7.
根据Ｋｕｌｌｅｎｂｅｒｇ的半理论半经验公式，利用渤海中部８号平台的观测资料，选择强风期的２月和弱风期的７月分别代表冬季和夏季，推算了渤海中部海域冬、夏两季的铅直扩散系数。计算结果表明：Ｋｚ值在强风期的２月最大可达５．５ｃｍ２／ｓ；在弱风期的７月跃层中可达０．０２～０．０４ｃｍ２／ｓ。 相似文献
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首次对浙北潮下带（０～－５ｍ）水域生物学调查表明：共鉴定底栖生物２２２种，隶属１０３科１７０属；该区生物数量较高（生物量为８０．８８ｇ／ｍ２，栖息密度为６５５个／ｍ２），以软体动物为主要类群；群落结构可划分为五个类型。底栖生物的分布与水域盐度、温度、底质性质、海湾屏蔽度有密切的关系。 相似文献
10.
本文对在南海中部布设的两个层次（１１９１ｍ和３６９６ｍ）沉积物捕集器的沉降粒子进行了颗粒沉降通量和氨基酸组成的研究。南海的物质通量呈现季节性变化，深层样变动范围在６９．６～１４１．７ｍｇ／（ｍ２·ｄ）；但火山灰侵入后，其物质通量（按每月平均）高出１～２个数量级，氨基酸和氨基糖含量亦由原来的１０×１０－３和０．９×１０－３减少为０．０９×１０－３和０．０２×１０－３。氨基酸组分中以天门冬氨酸占优势，其次为甘氨酸与谷氨酸。在火山灰影响下，其丰度顺序为：谷氨酸＞天门冬氨酸＞甘氨酸。 相似文献
11.
《Coastal Engineering》2002,46(2):139-157
At plunging breakers, air bubbles are entrained at the impingement of the water jet, formed at the top of the wave, with the water free surface in front. During the present study, air bubble entrainment at a pseudo-plunging breaker was investigated at near full-scale and further experimental work studied the bubble detrainment process. Experimental observations included the generation and propagation of waves downstream of the plunge point. Experimental results highlighted a number of unsteady air–water flow patterns and emphasise high levels of aeration: i.e., depth-averaged void fraction of more than 10% next to jet impact in shallow waters. Unsteady bubble injection experiments showed a strong vortical motion induced by the rising bubbles. Altogether, the results suggest that a dominant time scale is the bubble rise time d1/ur, which cannot be scaled properly with an undistorted Froude model. The study contributes to a better understanding of unsteady bubble entrainment at a pseudo-plunging breaker and the associated vortical circulation. 相似文献
12.
There has been much interest in detecting the presence of methane gas in the ocean. Although methane exists predominantly as methane hydrate (a buoyant compound) in the deep ocean, recent computer simulations and anecdotal evidence have reported that these hydrates will decompose to produce methane bubbles in shallower waters. This paper describes how the quality factor Q of oscillating bubbles can be used to distinguish methane bubbles (Q=24) from the air bubbles (Q=34) which are ubiquitous near the ocean surface. Values of Q are reported for bubbles in water at atmospheric pressure containing air, carbon dioxide, argon, helium, methane and butane. Possible acoustic techniques for detecting and sizing methane bubbles in the ocean are discussed briefly. 相似文献
13.
N. Vedachalam S. Ramesh P. Udaya Prasanth G. A. Ramadass 《Marine Georesources & Geotechnology》2018,36(8):966-973
Natural gas hydrates is considered as a strategic unconventional clean hydrocarbon resource in the energy sector. Understanding the behavior of the rising methane gas bubbles during production leaks from the deep marine gas hydrate reservoirs well head is essential for environmental impact studies and to design environmental monitoring systems. Numerical model for quantitatively characterizing the vertical dissolution pattern of the wellhead released methane gas bubbles is analyzed for three potential gas hydrate locations in India. Simulation results indicate that the methane bubbles with diameter of 10?mm can transport methane gas till 650, 800, and 750?m from the seabed in the Krishna–Godavari(KG), Mahanadi and Andaman basins respectively. Results brought out that potential well head damage during methane hydrate production at 1050?m water depth could release up to 28?m3 of methane gas, in which 50% of the molar mass shall get dissolved within 40?m of water column from the seafloor. 相似文献
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Water motion is a very important environment surrounding marine organisms. It is, however, difficult to measure currents with a propeller type of current meters in seagrass or seaweed beds in shallow waters. Therefore, we elaborate the measuring method of time-averaged intensity of water motion with plaster balls invented by Muus (1968) to set them at several depths at short vertical intervals in shallow waters. Theoretical examination is also made on the relation between speed of steady flow and dissolution rate of plaster balls by experiments in a circuit tank. These experiments revealed that the temporal rate of decrease in the 1/2 power of wet weight of plaster balls excluding a rod supporting the plaster ball was proportional to the speed of steady flow in the tank. On the basis of this relation, we propose the method for estimating the time-averaged intensity of water motion by converting the loss of wet weight of plaster ball to the speed of steady flow bringing equivalent loss. Since this method is simple and convenient, it can be applied to obtaining environmental indices of water motion not only in seagrass or seaweed forests, but also in fishing grounds culturingporphyra, yellow tail (Seriola quinqueradiata) or oysters. 相似文献
16.
为准确探讨破碎波作用下气体如何卷入以及气泡的形成与输运特性, 文章结合粒子图像测速技术(particle image velocimetry, PIV)、高速相机和气泡测量系统, 以及基于Navier-Stokes方程的三维数值模型对气泡形成及其运动过程进行研究。研究结果表明: 文章建立的数值模型能合理地捕捉到破碎波作用下气体的卷入及其输运过程; 波浪的破碎会形成较大的气腔, 其破裂过程又将产生大量的气体微团; 气泡会增加水体的紊动, 造成水体与空气交界面附近形成大量的漩涡以及水体的飞溅; 气泡的破裂会消耗大量的水体能量, 同时发现较大的紊动动能与气泡的生成有关, 且气泡数随平均紊动动能的增加呈线性增长关系。 相似文献
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Accurate propeller shaft speed controllers can be designed by using nonlinear control theory and feedback from the axial water velocity in the propeller disc. In this paper, an output feedback controller is derived, reconstructing the axial flow velocity from vehicle speed measurements, using a three-state model of propeller shaft speed, forward (surge) speed of the vehicle, and the axial flow velocity. Lyapunov stability theory is used to prove that a nonlinear observer combined with an output feedback integral controller provide exponential stability. The output feedback controller compensates for variations in thrust due to time variations in advance speed. This is a major problem when applying conventional vehicle-propeller control systems. The proposed controller is simulated for an underwater vehicle equipped with a single propeller. The simulations demonstrate that the axial water velocity can be estimated with good accuracy. In addition, the output feedback integral controller shows superior performance and robustness compared to a conventional shaft speed controller 相似文献
19.
风力对内陆浅水水域磷水平的影响 总被引：1，自引：0，他引：1
本文通过对平度市大泽山水库(面积约0.5平方公里,平均水深约1.5米)的实地观测,研究了风力对内陆浅水水域磷水平的影响。结果表明,影响程度取决于风速、风力作用时间、水深以及风力作用前磷水平的高低等因素。就大泽山水库而言,风速大于2.5米/秒的风力可引起各种形态磷的明显增加。不过对磷酸盐磷来说,如果浓度本来就较高,风力作用下当有大量沉积物颗粒泛起时,会对PO_4~≡产生吸附,因而可能导致水中游离磷酸盐磷含量下降。鉴于此,作者建议对内陆浅水水域进行磷水平调查时应考虑风力的作用。 相似文献