黄河入海泥沙对渤海和黄海沉积作用的影响

渤海平均水深18m，最大水深70m，是一个较浅的海湾。黄海平均水深38m，其中部为水深大于50m的盆地。它们的共同特征是陆地环绕。沿岸河流输沙特征对沉积作用过程有重大影响，特别是黄河入海泥沙的影响尤为显著。 关于黄河人海泥沙对渤海和黄海沉积作用的影响，前人已从不同角度进行过讨论。黄河是世界上著名的多沙性河流。由于黄河尾闾长期以来不断发生变迁，纵横摆动于华北平原之上，交替注入渤海和黄海，因此，在讨论黄河入海泥沙在中国近海沉积中的作用时，必须把渤海和黄海作为一个整体，甚至南涉东海。本文试图在以往工作的基础上，概括讨论黄河入海泥沙对渤海和黄海海底沉积作用的影响。     

对虾一种无包涵体杆状病毒病原的PCR检测

为建立对虾无包涵体杆状病毒的快速诊断技术,应用PCR技术分别对暴发性流行病发生前、流行中和发病后的对虾样品进行了检测.根据已克隆的对虾杆状病毒部分基因组序列而设计的引物能特异性地扩增出靶DNA片段,最低可以检测1pg的病素DNA.由典型发病症状对虾的胃、腮、肝胰腺、中肠、游泳足、肌内和心脏等器官和组织中成功地检测到病毒.不同组织和器官经扩增得到的信号强弱不同:病虾的胃扩增得到的信号最强,中肠、肌肉、心脏和游泳足次之,腮和肝胰腺信号最弱,说明病毒在不同组织和器官中数量及感染程度不同.在对虾发病前及发病后,用二次PCR还能检测表面不发病呈隐性感染状态的对虾携带的病毒;而对野生健康虾的检测结果为阴性.研究表明,PCR是检测对虾暴发性流行病快速、灵敏而准确的方法,对病毒病的早期诊断、防治和高健康对虾品种的选育具有指导意义.     

Measurement of 224Ra, 226Ra and 228Ra in seawater using Mn-fiber adsorption-γ spectrum method

I~IOXThe half-lives of natural radioactive nuclides "'Ra, 226Ra and 228Ra are 3. 66 d, 5. 76 a,1600 a respectively, hence, the marine process with various time scales can be researched by taking these nuclides as tracers. Because these nuclides can be determined by measuring them or theirdaughters' a,g, y-rays, they have been applied extensively in oceanography research. Huang(1996), Huang et al. (1996 a,b) and Chen (1996) have given reviews on it.Since the contents of "'Ra, 226Ra and 228…     

A dipole mode at thermocline layer in the tropical Indian Ocean

Temperature data at different layers of the past 45 years were studied and we found adiploe mode in the thermocline layer (DMT): anomalously cold sea temperature off the coast of Sumatra and warm sea temperature in the western Indian Ocean. First, we analyzed the temperature and the temperature anomaly (TA) along the equatorial Indian Ocean in different layers. This shows that stronger cold and warm TA signals appeared at subsurface than at the surface in the tropical Indian O-cean. This result shows that there may be a strong dipole mode pattern in the subsurface tropical Indian Ocean. Secondly we used Empirical Orthogonal Functions (EOF) to analyze the TA at thermocline layer. The first EOF pattern was a dipole mode pattern. Finally we analyzed the correlations between DMT and surface tropical dipole mode (SDM), DMT and Nino 3 SSTA, etc. and these correlations are strong.     

Cyclone formation and development in the Antarctic Prydz Bay

Using meteorological data of field observation in 1990 - 2000, especially polar orbit high-resolution NOAA satellite cloud maps received from the Antarctic expedition vessel since 1997, the formation and development of the Prydz Bay cyclone are studied in this paper. Some new viewpoints are suggested such as: when surround-polar cyclone enters the Prydz Bay, it can also intensify and develop in summer; cyclone can also develop in the easterlies in this bay. These view points revise old uncom-plete view point that the Prydz Bay is a burial ground of cyclone, and also further consummate formation-development theory of surround-cyclone in the Antarctic westerlies and cyclone in the Antarctic easterlies. In this paper, the mechanism of ice-air-sea interaction in the Prydz Bay is studied, and the physical process of cyclone formation-development is explained. By use of wholly dynamic transportation method, an energy exchange case of a cyclone, which explosively developed after entering the Prydz Bay, is calcu     

Measurement of nuclides of uranium and thorium series of disequilibrium using γ-spectroscopy

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Variation in Water Masses on Shelf of Northern Bering Sea in September 2016-2018

Abstract

Based on hydrological data obtained during the 7th to 9th Chinese National Arctic Research Expeditions in the summers of 2016–2018, the main water structure on the shelf of the northern Bering Sea and the volume and heat fluxes of the Bering Strait throughflow were analyzed. Distinct variability was identified in the three Pacific water masses feeding the strait - Anadyr Water (AW), Bering Shelf Water (BSW) and Alaskan coastal water (ACW). Overall, the temperature and salinity of the entire section increased each year, with 2018 showing significant anomalies, i.e., a temperature anomaly of up to 1?°C and a maximum salinity anomaly of 2. From 2016 to 2018, the extent of the ACW gradually narrowed in the eastern part of this section, while the AW expanded eastward each year. The net volume transport through each of the three sections increased poleward from 1.65?Sv to 2.76?Sv, with the AW increasing from 0?Sv to 1.03?Sv, the BSW varying between 0.52–1.65?Sv, and the ACW gradually decreasing from 1.04?Sv to disappearing completely. The net heat fluxes were also poleward, varying between 25.77 TW and 61.50 TW, and showing a significant increase. Significant variations in magnitude and extent were observed in each water mass of the Bering Strait throughflow, which could produce widespread effects in the Arctic Ocean and the global ocean beyond.     

A semi-analytical solution for random wave-induced soil response and seabed liquefaction in marine sediments

In this study, unlike most previous investigations for wave-induced soil response, a simple semi-analytical model for the random wave-induced soil response is established for an unsaturated seabed of finite thickness. Two different wave spectra, the B-M and JONSWAP spectra, are considered in the new model. The influence of random wave loading on the soil response is investigated by comparing with the corresponding representative regular wave results through a parametric study, which includes the effect of the degree of saturation, soil permeability, wave height, wave period and seabed thickness. The maximum liquefaction depth under the random waves is also examined. The difference on the soil response under the two random wave types, B-M and JONSWAP frequency spectra, is also discussed in the present work.     

A note on the effects of a thin visco-elastic mud layer on small amplitude water-wave propagation

In this note we investigated the effects of a thin visco-elastic mud layer on wave propagation. Within the framework of linear water-wave theory, analytical solutions are obtained for damping rate, dispersion relation between wave frequency and wave number, and velocity components in the water column and mud layer. The wave attenuation rate reaches a maximum value when the mud layer thickness is about the same as the mud boundary layer thickness. Heavier mud has a weaker effect on the wave damping. However, the wave attenuation rate does not always decrease as the elastic shear modulus increases. In the range of small values for elastic shear modulus, the wave attenuation can be amplified quite significantly. The current solutions are compared with experimental data with different wave conditions and mud properties. In general, good agreements are observed.     

锯缘青蟹NAGase的催化机理的判断

以p-硝基苯酚-β-D-氨基葡萄糖苷（pNP-NAG）为底物，研究产物类似物：p-羧基苯酚和苯酚对青蟹N-乙酰-β-D-氨基葡萄糖苷酶（NAGase，Ec3．2．1．52）活力的影响．结果表明：p-羧基苯酚和苯酚对该酶有抑制的作用，IC50分别为20．0和100．0mmol／dm^3．p-羧基苯酚和苯酚对酶的抑制均表现为竞争性类型，其抑制常数K1分别为5．03和25．67mmol／dm^3．结合产物N-乙酰-β-D-氨基葡萄糖（NAG）抑制作用表现为反竞争性类型，判断NAGase水解pNP-NAG反应为有序双双反应（Ordered Bi Bi）．