Computation of Viscous Uniform and Shear Flow over A Circular Cylinder by A Finite Element Method

The incompressible viscous uniform and shear flow past a circular cylinder is studied. The two-dimensional Navier-Stokes equations are solved by a finite element method. The governing equations are discretized by a weighted residual method in space. The stable three-step scheme is applied to the momentum equations in the time integration. The numerical model is firstly applied to the computation of the lid-driven cavity flow for its validation. The computed results agree well with the measured data and other numerical results. Then, it is used to simulate the viscous uniform and shear flow over a circular cylinder for Reynolds numbers from lO0 to lO00. The transient time interval before the vortex shedding occurs is shortened considerably by introduction of artificial perturbation. The computed Strouhal number, drag and lift coefficients agree well with the experimental data. The computation shows that the finite element model can be successfully applied to the viscous flow problem.     

热带印度洋偶极子发生和演变机制的数值研究

对中国科学院大气物理研究所(IAP)大气科学和地球流体力学数值模拟国家重点实验室(LASG)发展的第三代海洋模式(L30T63 OGCM)进行了改进。分析了该模式1959年1月—1998年12月的40a积分结果，以此研究热带印度洋偶极子发生、发展和消亡的物理机制。对数值模拟结果的分析表明，赤道印度洋表面异常东风引起的异常环流结构是偶极子发生、发展的主要动力学原因，其表面异常东风转换为异常西风所引起的异常环流结构调整是偶极子消亡的主要动力学原因；海气界面热通量异常的交换对热带印度洋海表温度距平偶极子模态的形成和演变起着重要的作用；垂直输送作用是热带印度洋次表层海温偶极子模态发生和演变的主要物理机制。     

Numerical simulation of solitary wave scattering by a circular cylinder array

The interaction of a solitary wave with an array of surface-piercing vertical circular cylinders is investigated numerically. The wave motion is modeled by a set of generalized Boussinesq equations. The governing equations are discretized using a finite element method. The numerical model is validated against the experimental data of solitary wave reflection from a vertical wall and solitary wave scattering by a vertical circular cylinder respectively. The predicted wave surface elevation and the wave forces on the cylinder agree well with the experimental data. The numerical model is then employed to study solitary wave scattering by arrays of two circular cylinders and four circular cylinders respectively. The effect of wave direction on the wave forces and the wave runup on the cylinders is quantified.     

中华齿米虾胰蛋白酶基因的研究

以中华齿米虾(Neocaridina denticulata sinensis)基因组DNA为模板,根据胰蛋白酶基因保守序列设计简并引物,利用PCR技术获得一个基因。序列分析表明此基因与已报道的凡纳滨对虾(Litopenaeus vannamei)胰蛋白酶基因有较高的相似度,序列中包含一个内含子和两个不完整的外显子,编码182个氨基酸残基。该氨基酸序列与凡纳滨对虾胰蛋白酶氨基酸序列的相似度为83.5%;含有胰蛋白酶所特有的His、Asp和Ser组成的活性三联体、决定胰蛋白酶底物专一性的Asp、底物结合部位的G1y残基。综合分析认定该基因为胰蛋白酶基因片断。将其氨基酸序列与报道的其他动物胰蛋白酶氨基酸序列进行了系统进化分析。系统进化分析的结果与现有以表型特征为依据的虾分类结果是一致的。     

杆状病毒感染越冬亲虾(Penaeus chenesis)的研究——越冬亲虾感染及其垂直传播的可能性

在中国对虾越冬亲虾中检出杆状病毒。经对病虾鳃、前中肠、卵巢组织进行电镜观察，在这些组织中发现大量有囊膜的杆状病毒。病毒粒子大小约为３６７ｎｍ×１２８ｎｍ，核衣壳为３２４ｎｍ×９２ｎｍ。病毒在细胞内不形成包涵体，在核内或在细胞质的发生基质中装配。从病毒的形态特征、感染组织以及典型的发病症状和病理变化，初步认为亲虾感染的病毒与近年广泛报道的造成养殖对虾大规模流行病的主要原因——中国对虾杆状病毒为同一种。卵巢组织也是病毒的主要靶器官之一，亲虾卵巢组织的被感染暗示着该病毒有可能通过生殖细胞而垂直传播     

大民屯凹陷地层水水文地质特征与油气聚集关系

对大民屯凹陷前第三系潜山、下第三系沙河街组地层水化学场研究发现，本区油田水总矿化度及二价阳离子浓度偏低，地层水总矿化度具有明显的垂向分带性，水体主要为陆相成因并受地表水渗入的影响较大，变质程度高，油田水的演化与盐类的溶解有关。该区地层水的流动受断裂和沉积砂体的控制，在水头压力、浮力动力场控制下其流动样式和分布规律反映了凹陷内油气的运聚规律，可为本区自生自储、新生古储式油气藏的判别提供有利证据。     

A Preliminary Study of Quantitative Distribution of Benthic Animals in the East China Sea Continental Shelf and Its Adiacent Waters

In October and November of 1977 and September and October of 1978,a quantitative survey of benthic animals was conducted in the East China Sea Continental Shelf and its adjacent waters(26°00'-34°00'N,124°00'-129°00'E,water depth 39-1550m),where 307 stations were dredged and 1200 samples collected.     

Selenium distribution in the Rhône delta and the Gulf of Lions

Total dissolved selenium and selenium species have been measured in the Rhône river delta and the Gulf of Lions within the framework of the EROS-2000 project. The Rhône river concentration of total selenium averages 2.30 nM with important variations related to river discharge. During estuar-ine mixing, the concentrations of total dissolved selenium, selenite and selenate (calculated as the difference between total dissolved and selenite) decrease linearly with increasing salinity, without significant interconversion between selenium species. In the open Mediterranean waters of the Gulf of Lions the total dissolved selenium increases from 0.5 nM in the surface waters to 0.9 nM in the deep waters. Organic selenium has been observed in Mediterranean deep water, an observation which is different from those from the Atlantic and the Pacific Oceans. The distributions of total inorganic selenium (Σ5e), selenite and selenate are strongly related to phosphate and silicate concentrations as observed previously for the major oceans.     

健康型牛蛙饲料养殖牛蛙的试验

本研究采用5种中草药添加剂配方的膨化饲料进行了为期36d的牛蛙养殖对比试验.结果表明，饲料中添加有中草药制剂的日摄食量明显大于对照组，日增重显著比对照组的高.而且大大加快了生长速度，缩短养殖周期，同时减少了染病机率，牛蛙体色鲜艳、光泽度极佳.     

四氯化碳对杜氏盐藻的毒性实验

按等浓度对数间距0．2设置毒物四氯化碳(CCl4)浓度对杜氏盐藻进行了毒性实验，根据细胞的生长以及β-胡萝卜素含量的变化，观察CCl4,对盐藻的毒性效应。结果表明，CCl4浓度小于0．13％时对盐藻生长及β-胡萝卜素累积几乎没有影响。盐藻对CCl4的最大耐受浓度为0．20％。CCl4浓度达到0．32％时，5天之后造成细胞全部死亡和β-胡萝卜素累积消失。