海藻中类胡萝卜素抗超氧自由基活性研究   总被引：2，自引：0，他引：2  

严小军  范晓  娄清香  刘晓妹 《海洋科学集刊》2001,(43):115-119

在植物组织内，类胡萝卜素除具有集光功能外，还具有其他的重要生物学功能，类胡萝卜素作为光保护剂可抵抗光、氧和光敏色素的有害作用，也可作为化学反应物抵抗细胞所产生的化学物质引起的氧化损伤，保护光合系统免受光动力敏化作用的破坏。类胡萝卜素光保护作用的主要机制如下:(1)类胡萝卜素对三重线态敏化剂的淬灭；(2)类胡萝卜素对1O2的淬灭；(3)类胡萝卜素对自由基反应的抑制，它的这种生物学活性在医学领域也具有重要的应用价值。胡萝卜素在生物系统中的保护作用包括失活由电激活的单线态氧(1O2)，失活反应性的化学物质如过氧化物自由基和烷氧基，这些自由基产生于细胞内，并可能会引起有害的氧化作用。类胡萝卜素的保护功能与直接的抗氧化活性或与对细胞内抗氧化水平的调节有关(Krinsky，1990)。对于类胡萝卜素清除脂类过氧化物自由基的能力和作用机理已经进行了详细的研究(Burton et al.，1984; Burton, 1989; Terao，1989; Palozza et al.，1992b; Tsuchihashi et al.，1995)，但对于类胡萝卜素清除超氧阴离子自由基的能力尚未见有详细研究报道。本文以邻苯三酚自氧化体系作为超氧自由基的发生体系，对海藻中分离纯化制备的类胡萝卜素清除该种自由基的能力进行了初步的探讨。  相似文献   

Estimation of Axial Pile Bearing Capacity According to Shear Strength Parameters of Soil     

Yu Xiaodong  Yan Shuwang Sun Wanhe Postgraduate Student  Tianjin University  Tianjin Professor  Tianjin University  Tianjin Senior Engineer  Tianjin Port Engineering Institute  Tianjin 《中国海洋工程》1997,(2)

At pesent,it is very popular to estimate pile bearing capacity by use of empirical formula andphysical indexes of soil provided in the design codes for civil construction in China.This paper attempts toapply mechanical indexes of soil and semi-empirical formulas,which are based on soil mechanical theoriesand were summarized and presented by Meyerhof in 1976,to calculate the axial pile bearing capacity.Lo-ading test results of 24 single piles in Tianjin area have been collected and compared with the proposed cal-ulation approach.  相似文献   

Model Test of Sand Restraining Force on Pipeline     

Zhang Jianguo Yan Chi Yan Shuwang Lecturer  Dept. of Hydraulic Eng.  Tianjin University  Tianjin Associate Professor  Dept. of Hydraulic Eng.  Tianjin University  Tianjin Professor  Dept. of Hydraulic Eng.  Tianjin University  Tianjin 《中国海洋工程》1996,(1)

This paper describes the model tests for determining the axial friction and the lateral resistance of sand to pipeline by using fine sand and prototype pipeline, and the calculation method based on limit analysis theory is verified. The effect of cyclic loading is considered in the test.  相似文献   

Holocene cheniers in the Yangtze Delta, China   总被引：1，自引：0，他引：1  

Qinshang Yan  Shiyuan Xu  Xusheng Shao 《Marine Geology》1989,90(4):337-343

Nineteen cheniers formed in the middle and late Holocene have been distinguished and studied.

In fair weather the wave action along the Yangtze Delta is weak, with a wave height of 0.5–1.0 m and average wave energy of 0.127 erg/s. However, in late summer and early autumn the coastal area is usually swept by typhoons, which sometimes are extremely violent. The development of cheniers is mainly controlled by these strong typhoons. As a result, a number of the sedimentary characteristics of the cheniers are related to the typhoon-generated high-energy environment.

Moreover, the study shows that the top elevation of a fully developed chenier indicates the spring high water level during a violent typhoon (11–12 on the Beaufort scale).  相似文献   

魁蚶线粒体16S rRNA和COI基因片段序列测定及其应用前景   总被引：10，自引：0，他引：10  

孔晓瑜  姜艳艳  相建海  喻子牛  刘亚军 《海洋科学》2001,25(12):46-48

魁蚶（Ｓｃａｐｈａｒｃａｂｒｏｕｇｈｔｏｎｉｉ）是蚶科贝类的一种大型经济种类，主要分布于我国、日本和朝鲜半岛及俄罗斯东南部沿海。在我国，主要分布于辽宁、河北和山东沿海，生活在３～５０ｍ（多为２０～３０ｍ）水深的软泥或泥沙质海底，是我国北方沿海重要的经济贝类之一。但但有有关关其其自自然然群群体体的的遗遗传传变变异异及及群群体体间间遗遗传传分分化化等等方方面面的的研研究究不不多多 ;;同同时时，，作作者者和和日日本本研研究究者者发发现现，，中中国国、、韩韩国国和和日日本本魁魁蚶蚶群群体体在在形形态态和…  相似文献   

珠江口东南近海海区污损生物研究   总被引：4，自引：2，他引：4  

严涛  严文侠  董钰  梁冠和  严岩  王华接 《海洋学报》2003,25(6):117-125

为研究珠江口东南近海海区污损生物状况,于1986年5月至1987年6月,在香港东南约114和160km,水深为95和113m处布设了两个生物浮标站,并对距香港约172km,水深为115m处的Marex水文气象浮标上的污损生物群落进行调查.此次调查共采集和鉴定出污损生物78种,其中在浸海只有3个月的试板上,主要有柄蔓足类、水螅和藻类,优势种是细板条茗荷、茗荷和直杯螅.至于浸海时间达6～12个月的浮标(包括沉标)及锚链系统,其上还有相当数量的多种双壳类软体动物、无柄蔓足类和苔藓动物等硬性污损生物附着.在种类垂直分布方面,污损生物群落组成随深度发生明显变化.  相似文献   

An Experimental Study of Several Special Issues Regarding the Ice Force on Conical Structures     

SHI  Qing-zeng 《中国海洋工程》2002,16(4):561-568

The effect of the cone spacing of a conieal structure on the ice force is studied by model experiments. The ice force reduction coefficient presented in this paper expresses the relationship between the ice force and the arrangement of cones. The experiments prove that the mode of the ice failure before the boundary of upward-downward bending cone (UDBC) is crushing. A conclusion can also be drawn from the experiments that the ice force on the boundary of UDBC is by far less than that on a vertical pile with the same diameter. Moreover, the ice force frequencies on upright and inve-rted cones are obtained under the field condition of the platform JZ20-2, respectively. The results show that the alterna-tion of the ice force on UDBC can hardly induce resonance of platform JZ20-2.  相似文献   

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

Yingjie Wang  Na Liu  Lina Lin  Yan He  Bin Kong  Zhanhai Zhang 《Marine Geodesy》2020,43(3):285-301

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.  相似文献   

Ice-Induced Fatigue Analysis by Spectral Approach for Offshore Jacket Platforms with Ice-Breaking Cones     

岳前进刘圆  张日向屈衍 王瑞学 《中国海洋工程》2007,21(1):1-10

The spectral methods and ice-induced fatigue analysis are discussed based on Miner's linear cumulative fatigue hypothesis and S-N curve data.According to the long-term data of full-scale tests on the platforms in the Bohai Sea,the ice force spectrum of conical structures and the fatigue environmental model are established.Moreover,the finite element model of JZ20-2MSW platform,an example of ice-induced fatigue analysis,is built with ANSYS software.The mode analysis and dynamic analysis in frequency domain under all kinds of ice fatigue work conditions are carried on,and the fatigue life of the structure is estimated in detail.The methods in this paper can be helpful in ice-induced fatigue analysis of ice-resistant platforms.  相似文献   

Model Test Study of Dynamic Ice Force on Compliant Conical Structures     

黄焱  史庆增宋安 《中国海洋工程》2007,21(1):11-22

To study ice-induced vibration of a compliant conical structure,a series of model tests were performed from 2004 to 2005.In the tests,the ice sheet before the compliant conical structure was found to fail in two-time breaking.From 2005 to 2006,this type of ice failure was studied through more groups of tests.The tests show that two-time breaking is the typical failure of ice before steep conical structures,and is controlled by other factors at the same time,such as ice speed and the angle of the cone.  相似文献