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121.
本文对1987~1988年在山东省部分海岛底栖生物调查时发现的异毛虫科5个种进行了详细的描述并配有插图,其中一种为新亚种,另有3个种在我国为首次记录。  相似文献   
122.
2001-2002年天目湖(沙河水库)浮游植物的生态学研究   总被引:7,自引:0,他引:7  
2001年6月~2002年5月,对天目湖进行的浮游植物周年调查表明,天目湖共有浮游植物7门75属,其中年平均丰度为5026.20×104个/L,以蓝藻为主,占总丰度的54.45%;而年平均生物量为(15.364±9.103)mg/L,其中硅藻居首位,为6.634 mg/L,占浮游植物年平均生物量的43.18%;其周年变化是丰度和生物量最高值均出现在5月,丰度在5月和9月出现2个峰值,而生物量则在5、7、10月出现3个峰值。浮游植物丰度从大坝处1#点到河流入湖口的9#、10#点变化不明显但略有增加,而生物量则呈明显增加。通过对水温、透明度、营养盐与浮游植物丰度和生物量的线性回归分析发现,浮游植物丰度、生物量与水温、TP存在显著的正相关,而与N/P比、透明度存在显著性负相关,与TN相关性不是很明显。  相似文献   
123.
生物胺对锯缘青蟹大颚器发育的调节作用   总被引:1,自引:0,他引:1       下载免费PDF全文
雌性锯缘青蟹(Scylla serrata)于实验的第1天、第5天、第10天,分别注射100μL剂量为1μg/g体质量的5-HT,OA和DA,第15天解剖。结果表明,5-HT对锯缘青蟹大颚器发育具有显的促进作用,OA和DA的作用不明显。经免疫细胞化学检测,大颚器内存在5-HT免疫阳性细胞,免疫阳性细胞多数为卵圆形,少数具有很长的胞突,该结果首次为5-HT参与大颚器的生理活动提供了形态学证据。  相似文献   
124.
热带气旋是夏季影响渤海的灾害性天气系统之一。其影响路径主要有三类,各类路径在影响时前期中高纬500hPa高空环流形势及夏季西太平洋副热带高压特征指数有显著差异。  相似文献   
125.
重锤式拖网取样器是对现行常规拖网的技术改进。通过理论模型设计与机械加工试验,研制出了一套重锤机械结构。该机构在拖网取样时利用钢缆拉力蓄积能量拉动内部拉杆,并通过销轴机构释放能量加速冲击芯块,撞击壳体产生巨大的瞬时冲击力,拽动拖网破碎岩石,然后使用复位弹簧使机构复位,重新工作。可以使常规拖网取样器和牵引钢缆更加安全,并大大提高拖网作业的成功率与效率。  相似文献   
126.
对氯甲烷的海洋生物地球化学循环的研究进展进行述评。介绍了氯甲烷在海洋环境中的来源、分布、去除、海-气通量、大气氯甲烷的源、汇估算及海水中氯甲烷的分析方法等方面,并提出在国内海域进行氯甲烷研究的几点设想。  相似文献   
127.
介绍了国外在布莱克海隆(包括ODP164航次994、995、997站位)进行天然气水合物勘查过程中应用稳定同位素的研究实例;通过对这3个站位样品的甲烷、CO2、DIC(dissolved inorganic carbon)、有机碳以及自生碳酸盐的δ^13C分析,指出浅部(0-30m)甲烷和DIC的δ^13C值随深度迅速降低又迅速升高的变化可以作为天然气水合物存在的地球化学指标。994站位孔隙水δ^18O值深度从0.30‰下降到-0.37‰;氢同位素δD随深度略有下降(从11‰到-12‰),这与水合物形成时氢氧重同位素相对富集于固相有关,表明天然气水合物的存在。997站位δ^37Cl从海底沉积物表层以下30m处为接近海水的最大值0,至钻孔底746.85m处降为-3.68‰,可能也与天然气水合物的形成有关。  相似文献   
128.
A novel method for prediction of the load carrying capacity of a corroded reinforced concrete beam (CRCB) is presented in the paper. Nine reinforced concrete beams, which had been working in an aggressive environment for more than 10 years, were tested in the laboratory. Comprehensive tests, including flexural test, strength test for corroded concrete and rusty rebar, and pullout test for bond strength between concrete and rebar, were condueted. The flexural test results of CRCBs reveal that the distribution of surface cracks on the beams shows a fractal behavior. The relationship between the fractal dimensions and mechanical properties of CRCBs is then studied. A prediction model based on artificial neural network (ANN) is established by the use of the fractal dimension as the corrosion index, together with the basic intbrmation of the beam. The validity of the prediction model is demonstrated through the experimental data, and satisfactory resuits are achieved.  相似文献   
129.
In 2001 and 2002, Australia acquired an integrated geophysical data set over the deep-water continental margin of East Antarctica from west of Enderby Land to offshore from Prydz Bay. The data include approximately 7700 km of high-quality, deep-seismic data with coincident gravity, magnetic and bathymetry data, and 37 non-reversed refraction stations using expendable sonobuoys. Integration of these data with similar quality data recorded by Japan in 1999 allows a new regional interpretation of this sector of the Antarctic margin. This part of the Antarctic continental margin formed during the breakup of the eastern margin of India and East Antarctica, which culminated with the onset of seafloor spreading in the Valanginian. The geology of the Antarctic margin and the adjacent oceanic crust can be divided into distinct east and west sectors by an interpreted crustal boundary at approximately 58° E. Across this boundary, the continent–ocean boundary (COB), defined as the inboard edge of unequivocal oceanic crust, steps outboard from west to east by about 100 km. Structure in the sector west of 58° E is largely controlled by the mixed rift-transform setting. The edge of the onshore Archaean–Proterozoic Napier Complex is downfaulted oceanwards near the shelf edge by at least 6 km and these rocks are interpreted to underlie a rift basin beneath the continental slope. The thickness of rift and pre-rift rocks cannot be accurately determined with the available data, but they appear to be relatively thin. The margin is overlain by a blanket of post-rift sedimentary rocks that are up to 6 km thick beneath the lower continental slope. The COB in this sector is interpreted from the seismic reflection data and potential field modelling to coincide with the base of a basement depression at 8.0–8.5 s two-way time, approximately 170 km oceanwards of the shelf-edge bounding fault system. Oceanic crust in this sector is highly variable in character, from rugged with a relief of more than 1 km over distances of 10–20 km, to rugose with low-amplitude relief set on a long-wavelength undulating basement. The crustal velocity profile appears unusual, with velocities of 7.6–7.95 km s−1 being recorded at several stations at a depth that gives a thickness of crust of only 4 km. If these velocities are from mantle, then the thin crust may be due to the presence of fracture zones. Alternatively, the velocities may be coming from a lower crust that has been heavily altered by the intrusion of mantle rocks. The sector east of 58° E has formed in a normal rifted margin setting, with complexities in the east from the underlying structure of the N–S trending Palaeozoic Lambert Graben. The Napier Complex is downfaulted to depths of 8–10 km beneath the upper continental slope, and the margin rift basin is more than 300 km wide. As in the western sector, the rift-stage rocks are probably relatively thin. This part of the margin is blanketed by post-rift sediments that are up to about 8 km thick. The interpreted COB in the eastern sector is the most prominent boundary in deep water, and typically coincides with a prominent oceanwards step-up in the basement level of up to 1 km. As in the west, the interpretation of this boundary is supported by potential field modelling. The oceanic crust adjacent to the COB in this sector has a highly distinctive character, commonly with (1) a smooth upper surface underlain by short, seaward-dipping flows; (2) a transparent upper crustal layer; (3) a lower crust dominated by dipping high-amplitude reflections that probably reflect intruded or altered shears; (4) a strong reflection Moho, confirmed by seismic refraction modelling; and (5) prominent landward-dipping upper mantle reflections on several adjacent lines. A similar style of oceanic crust is also found in contemporaneous ocean basins that developed between Greater India and Australia–Antarctica west of Bruce Rise on the Antarctic margin, and along the Cuvier margin of northwest Australia.  相似文献   
130.
传统的海湾(泻湖)纳潮量计算方法不能精确地反映潮间带被部分围垦后纳潮量的实际情况,本考虑围堤的影响,将纳潮量分解为堤基以下的“梯形”区和堤基以上的“矩形”区两部分之和,在理论上更加严密。根据改进后方法算出的胶州湾近期纳潮量比传统方法算出的纳潮量大15%左右。可见,半个多世纪以来胶州湾的纳潮量只减少了约15%.而不是传统方法得出的约25%。  相似文献   
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