北仑港区宁波组晚大理冰期气候特征     

陈俊义 《海洋学研究》1991,(1)

以往认为宁波组沉积时期的古气候为寒冷干燥或冷凉干燥。本文依据北仑B_(12)孔的孢粉资料,阐明在这一冷期中曾有一次相对较暖的气候波动,据此又可分冷凉—温和—温凉三个阶段,湿度以略湿为主。此外,还讨论了本区在晚大理冰期温度、湿度的变化特点。  相似文献   

富含半胱氨酸肠蛋白的研究进展     

陈燕  孙晨 《海洋科学》2020,44(6):148-151

富含半胱氨酸肠蛋白是一种含双锌指结构的小分子蛋白，其在锌离子转运、个体发育、免疫防御以及肿瘤发生等多种生理过程中发挥重要作用。作者主要对富含半胱氨酸肠蛋白的结构特点及其在发育和免疫方面的研究进展进行系统概述，并指出其相关作用机制尚待深入研究。  相似文献   

高纯河豚毒素对蛙坐骨神经动作电位的影响     

赵立强  许晨  叶本兰  张业  洪专 《台湾海峡》2007,26(3):410-414

用电生理学方法观察了4种不同浓度的高纯河豚毒素(tetrodotoxin,TTX)对蛙离体坐骨神经动作电位的影响.实验结果表明:1μmol/dm3TTX在给药后7 min能显著抑制动作电位的上相幅度(P<0.05),但在给药后10 min才显著抑制动作电位的下相幅度(P<0.01);20μmol/dm3TTX在给药后3 min内能完全抑制动作电位的形成.1μmol/dm3TTX在给药后1~5min对动作电位传导速度的影响没有统计学意义,5μmol/dm3TTX在5min时可显著抑制传导速度(P<0.05),而10μmol/dm3TTX在2min时便显著抑制传导速度(P<0.05).实验结果提示高纯河豚毒素对蛙离体坐骨神经动作电位的影响存在剂量效应关系.  相似文献   

Numerical and simplified methods for the calculation of the total horizontal wave force on a perforated caisson with a top cover     

Xuefeng Chen  Yucheng Li  Bin Teng 《Coastal Engineering》2007

The VOF method and the k–ε model, combined with the equation of state of air at constant temperature, have been used to calculate the total horizontal wave force caused by monochromatic waves acting on a perforated caisson with a top cover. From comparison of various parameters, such as the total horizontal force, the pressure difference on the front wall, the pressure on the back wall and the pressure on the top cover, between the numerical results and test data, it can be seen that the numerical results agree well with the test data. It is concluded that the method described in this paper can be utilized to calculate wave forces acting on perforated caissons with a top cover in the case of nonovertopping, nonbreaking waves. A simplified method to calculate the total horizontal force has been developed, based on test data, using a least-squares method. A comparison between the numerical results and the values calculated from the simplified equations shows good agreement. Therefore the simplified equations can be used in engineering applications to evaluate the total horizontal force on a perforated caisson with a top cover.  相似文献   

海水分光反射率与叶绿素浓度的相关分析     

傅克忖  曾宪模 《海洋科学进展》1995,(1)

通过对东京湾两年度不同季节海水分光反射率与叶绿素浓度进行统计分析，结果表明，叶绿素浓度Ｃ与两谱段分光反射率之比Ｒｗ（λｊ）／Ｒｗ（λｊ）具有幂函关系Ｃ＝Ａ［Ｒｗ（λｊ）／Ｒｗ（λｊ）Ｂ。两者的对数显示出较好的线性关系，即ｌｏｇＣ＝ｌｏｇＡ＋Ｂｌｏｇ［Ｒｗ（λｊ）／Ｒｗ（λｊ）］。负相关系数达０．９９。相关方程之一为Ｃ＝３．３２９［Ｒｗ（５２０）／Ｒｗ（５５０）］－１．３８４（１９８７年６月初）．在梅雨季节之后，相关方程为Ｃ＝１２．６８［Ｒｗ（５２０）／Ｒｗ（５５０）］－２．０１０（１９８８年８月）。这表明了海湾或混浊的沿岸水质，在叶绿素浓度算法中，统计参数Ａ和Ｂ的确立，要基于不同季节不同水质的现场观测资料。  相似文献   

海带雌性原生质体的分离与培养     

秦松  王希华  童顺  曾呈奎 《海洋与湖沼》1995,26(S1):126-129

于1993年1月 - 1993年4月，为了制备遗传性纯一的基因工程受体，用酶法从海带雌配子体单性生殖系分离雌性单倍体原生质体。从皱纹盘鲍消化腺及消化器官提取出鲍酶，在25°C下、1％（W／V）的鲍酶与2％（W／V）的纤维素酶（Onozuka R－10）合用能有效解离单细胞和原生质体。海带雌性原生质体经2d培养再生了细胞壁。  相似文献   

南海輓近海平面变化与构造升降初步研究     

刘以宣  詹文欢  陈欣树  陈俊仁  陈特固  许时耕 《热带海洋学报》1993,(3)

揭示南海輓近海平面变动和古岸线诸多遗迹,探讨晚更新世以来海平面变化一般规律,初步分析南海周缘中全新世和现代地壳构造升降速率,得出本区海平面上升率适中参考值为0.10—2.0mm/a,初步估算未来50年内海平面变化趋势在1.26—4.0mm/a之间;而构造升降受块断差异运动控制,一般规律是南海北部沿岸自东向西递减,由福建南部1.15mm/a至海南岛南部0.54mm/a。近代地壳形变资料亦证实这种变化规律。  相似文献   

湄洲湾表层沉积物中重金属的地球化学特征   总被引：6，自引：2，他引：6  

许爱玉  陈松 《台湾海峡》1993,12(1):16-20

根据1984年湄洲湾表层沉积物中重金属的分析资料,讨论了它们的地球化学特征和主要来源。沉积物中重金属的含量(Fe、Mn、Cu、Ni 的质量分数均值分别为3.21%、730×10~(-6)、19.4×10~(-6)、44×10~(-6)分布比较均匀,Pb、Zn 和Co 含量(质量分数均值分别为47.0×10~(-6)、25.8×10~(-6)和243×10~(-6))偏高,微量金属含量不受Fe-Mn 氧化物和有机物控制,本地区的金属来源受陆源输入的影响明显。  相似文献   

Impact Buckling and Post-Buckling of Elasto-Viscoplastic Cylindrical Shell Under Torsion     

Wang Deyu Chen Tieyun Associate Professor 《中国海洋工程》1997,(1)

The dynamic torsional buckling and post-buckling of elasto-plastic circular cylindrical shell isstudied.By the usage of the Bodner-Partom constitutive relation,the present visco-plastic problem is treat-ed as an orthotropic elastic problem.Based on the nonlinear large deflection shell therory,the governingdynamic buckling equation is solved by the Runge-Kutta method,and the critical buckling stress is deter-mined by the B-R criterion.The present paper is mainly focused on the imperfection sensitivity,the strainrate sensitivity,and the dynamic post-buckling characters for the shell loaded dynamically with a constantshear strain rate.Numerical results show that the critical shear stress and imperfection sensitivity will in-crease with the increase of strain rate.It is found that the elastic buckling stress is more sensitive toimperfection than the visco-plastic buckling.The present research also reveals some dynamic post-bucklingcharacters for the cylindrical shell,and it is shown that the shell will vibra  相似文献   

Research on Characteristics of Density Current Under the Action of Waves     

Li Dashan  Shen Ying  Ren Rushu Chen Yao Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Associate Professor  Hohai University  Nanjing Master  Hohai University  Nanjing 《中国海洋工程》1997,(1)

In this paper,the characteristics of density current under the action of waves are describedwith the help of flume experiment and theoretical analysis.The study shows that turbid water under the ac-tion of the waves can present three types of motion,i.e.significant stratification,fragile stratification andstrong mixing.The motion of turbid water presents significant stratification when(H/D)/△ρ/ρ~(1/2)≤4.5,generally this state is known as density current.The formulas of motionvelocity,thickness,and discharge of density current moving on horizontal bottom are derived by use of ba-sic equations such as momemtum equation,equation of energy conservation and continuity equation offluid.The time-average velocity and the thickness of density current under the action of waves have a rela-tionship with such parameters as relative density(△ρ/ρ),wave height(H),and water depth(D).Whenthese parameters are determined,the time-average thickness and motion velocity of density current are al-so determined.The relat  相似文献