流褶层及韧变带研究     

李三忠  杨振升 《国土资源》1994,(Z1)

流褶层与韧变带是地壳拉伸变形，顺层固态流变作用下的产物。流褶层是以原始层理为变形面或再经递进变形的褶皱变形岩层或岩石共生组合层位。韧变带具明显的层控性，受岩石成分和应变程度控制，不同环境和不同成分岩石的韧变带具有相异的组合型式和变形机制，井具有一定的递变规律。流褶层和韧变带可分属不同层位，但流褶层可实现向韧变带的转化。  相似文献   

第一代恒星的观测和研究进展     

陆烨  赵刚  梁艳春 《天文学进展》2001,19(4):470-476

第一代恒星（星族Ⅲ恒星）标志着宇宙从暗物质时代到现在已知的宇宙的转折点。目前对第一代恒星（星族Ⅲ恒星）的观测结果表明，在银河系中还没有发现零金属丰度的恒星，金属丰度[Fe/H]≤-2.5的恒星极少。由于近几年的BPS巡天，银河系中已知的极端贫金属丰度的恒星数目大大增多。目前，可探测到的极端贫金属星的金属丰度[Fe/H]最低约为－4．1。金属丰度在－4到－3之间的恒星大约有100多颗，这些恒星的运动学特性非常类似于其它晕星。然而还没有发现第一代恒星，或金属丰度[Fe/H]≤-5的恒星。关于第一代恒星的形成过程、初始质量函数以及存在于银河系的什么地方，都还没有任何直接的证据。但第一代恒星确实存在。第一代恒星这个谜一般的实体，向观测和理论天文学家提出了巨大挑战。为探测和预言银河系中的第一代恒星，天文学家提出了许多观测方案和理论模型。对有关第一代恒星在观测和理论研究上的进展进行了综述。  相似文献   

马面卵巢在不同贮藏温度下磷脂成分的变化     

杨文鸽  钱云霞  洪鹏志 《广东海洋大学学报》2001,21(1):35-38

在20℃、4℃、-10℃、-20℃四种温度下贮藏马面卵巢，对其中磷脂含量的变化进行了测定，并利用薄层层析分析测定了不同温度下贮存3d后马面卵巢中磷脂各组分的相对百分比。结果表明马面卵巢中磷脂的损失率随贮藏温度的上升而增加；在不同温度下贮藏3d，磷脂各组分的相对百分比都发生了变化；随贮藏温度的升高磷脂酰胆碱的降解速度大大加快，所占的百分比快速下降，而溶血磷脂酰胆碱的比例有不同程度的增加。相对而言，-20℃下贮藏数天，磷脂的含量及组分的变化较小。  相似文献   

EFFECT OF LIGHT INTENSITY ON THE TOTAL LIPID AND FATTY ACID COMPOSITION OF SIX STRAINS OF MARINE DIATOMS     

梁英麦康森  孙世春于道展 《中国海洋湖沼学报》2001,19(3):249-254

The effect of light intensity ( 1500 Ix and 5000 Ix) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211 ), Phaeodactylum tricornutum (Bl14, Bl18 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated.The total lipids of B13, Bl14, and B211 grown at 5000 Ix were lower than those grown at 1500 Ix. No evident changes were observed in Bl18, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:l(n- 7) and 20:5(n-3) . Cylindrothecafusiformis had high percentage of 20:4n - 6 (9.2 - 10.9% ) . The total polyunsaturated fatty acid /rl all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.  相似文献   

广东省拖网网囊调查     

杨吝  张旭丰  孙典荣  谭永光 《广东海洋大学学报》2001,21(4):22-26

为实施中华人民共和国国家标准《南海区拖网网囊最小网目尺寸》,对广东省范围内拖网网囊现状进行摸底调查,结果表明,广东省沿海拖网渔船现用网囊网目尺寸(内径)在16.7～35.2 mm范围内,总体平均为27 mm,均未能达到1989年国家技术监督局发布的中华人民共和国国家标准--《南海区拖网网囊最小网目尺寸》--内径39 mm.  相似文献   

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China——Ⅳ：Study on cross-bay transect from estuary to ocean   总被引：1，自引：0，他引：1  

Yang Dongfang  Chen Yu  Gao Zhenhui  Zhang Jing  Wang Fan 《中国海洋湖沼学报》2005,23(1):72-90

The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m³/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05–0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55 (mgC/m²·d)/(m³/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m²·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs. 1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth. This study was funded by NSFC (No. 40036010), and the Director's Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.  相似文献   

康古尔塔格缝合带的变形机制     

王洋  陈练武 《地球科学与环境学报》1996,(4)

北天山东段康古尔塔格带是晚古生代塔里木板块和准噶尔板块碰撞的结果。它是一条复杂的、强烈的高应变带．并具有独特的变形机制、应变序列以及构造变形。本文运用构造－地层研究方法对该碰撞带的构造特征加以分析和研究。  相似文献   

Energy flow in Branchiura sowerbyi (Oligochaeta: tubificidae) in a shallow macrophyte-dominated lake, Biandantang Lake     

Yan Yunjun  Liang Yanling 《中国海洋湖沼学报》2004,22(4):403-407

The energy flow ofBranchiura sowerbyi was studied for the first time in China in a shallow macrophytic lake, Biandantang Lake, Hubei Province. The energy flow was calculated from the measurement of flesh production (12.5241kJ/m²a), egestion (517.7302kJ/m²a), metabolism (38.3273 kJ/m²a), and excretion (4.3798kJ/m²a). The net growth efficiency of the species is about 22.7%, which accords well with the generally reported value for oligochaetes. In addition, the relationship between starvation respiration (R, mgO₂/ind·d), wet weight (Ww, mg) and temperature (T, °C) were also measured, with the regression function beingR=0.008Ww^0.736 e^0.050T. Project supported by NSFC (30270278, 3960019), the foundation of the government of Hubei Province (No. 2000J109), and the foundation of Ecological Station, CAS in the Institute of Hydrobiology.  相似文献   

基于Chandra的活动星系核观测     

李丹丹  王竞  陈阳  何香涛 《天文学进展》2005,23(3):239-247

活动星系核（AGN）是宇宙中最奇特的天体之一。它是真正意义上的全波天体，其中X射线波段的发射功率占到全波段功率的50％左右。AGN的X射线辐射研究涉及天体物理中的最基本问题，例如能量产生、辐射机制和宇宙论等，而Chandra X射线卫星的高分辨率图像和光谱对这一研究有着重要作用。以Chandra卫星的部分观测结果为例，简要介绍了几类不同类型AGN的X射线辐射研究进展：（1）宽吸收线类星体APM08279＋5255（z=3．91）的X射线谱分析，以及高红移类星体的观测概况；（2）Seyfert星系NGC 4151延展X射线发射问题的解决，及NGC 1068X射线辐射与光学波段的高激发态发射线（[OⅢ]λ5007）有很强相关性的发现；（3）6个BLLac天体样本的X射线环境分析；（4）射电星系X射线喷流的观测等。  相似文献   

ENERGY FLOW OF BELIAMYA AERUGINOSA IN A SHALLOW ALGAL LAKE, HOUHU LAKE （WUHAN, CHINA）     

Yan Yun-jun  Liang Yan-ling  Wang Hong-zhu 《中国海洋湖沼学报》2001,19(3):243-248

The energy budget ofBellamya earuginosa in a shallow algal lake, Houhu Lake (Wuhan, China) was investigated by the measurement of flesh production (32.8 kJ/(m²·a)), egestion (337.7 kJ/(m²·a)), metabolism (246.7 kJ/(m²·a)), and estimation of excretion (21.4kJ/(m²·a)). The net growth efficiency of the species is about 10.9%, which accords with the generally reported value for gastropods. In addition, the relationships between starvation respiration (R, mgO₂/(Ind·d)), body weight (Wd, mg in dry wt) and temperature (T, °C) were also determined. The regression equationR=0.044Wd ^0.537 e ^0.061T was obtained by the least square method, The measured SDA of the species is 26.51% of its gross metabolism. Project No. 3960019 and 39430101 supported by NSFC and also a granted for the East Lake Ecological Experimental Station, CAS, Wuhan.  相似文献