旧金山湾卤虫在同安盐田实验池中种群动态的初步分析

美国旧金山湾卤虫于1989年引入同安盐田实验池养殖,1989年10月至1990年3月池内人工养殖卤虫的结果表明,秋、冬两季实验池的水温变化不是影响卤虫种群数量变动的主要原因,卤水盐度的变化对卤虫幼体群体数量有较大的影响,饵料是影响卤虫种群变动的主要因子,使用花生渣饼磨浆后投喂卤虫比使用干鸡粪更有利于卤虫种群的增长。实验证实旧金山湾卤虫能在同安盐田安全越冬.     

Ocean bottom friction study from numerical modelling of sea surface height and SEASAT-ALT data

Tidal dissipation at the ocean floor has long been regarded as an adquated explanation to the behaviour of lunar orbit and Earth's rotation, although the actual mechanism involved is yet a fascinating research subject to date. The most common way to evaluate the dissipation is to find the rate of work done per unit surface by the current on the sea floor (Munk and Mac Donald 1960, Lambeck 1975). The success of this approach rely on the knowledge of the frictional coefficient which links the frictional force at the ocean floor, either quadratically or linearly, with the current velocity. Not only is the frictional coefficient important in this context, a variety of storm surge and tidal modelling problems also require a similar dissipation meachanism (Heaps 1969, Grace 1930, Stock 1976 etc.). The University of Manitoba, Center for Precambrian Studies Publication No. 089     

Studies on Stochastic Parametric Roll of Ship with Stochastic Averaging Method

The paper studies the parametric stochastic roll motion in the random waves. The differential equation of the ship parametric roll under random wave is established with considering the nonlinear damping and ship speed. Random sea surface is treated as a narrow-band stochastic process, and the stochastic parametric excitation is studied based on the effective wave theory. The nonlinear restored arm function obtained from the numerical simulation is expressed as the approximate analytic function. By using the stochastic averaging method, the differential equation of motion is transformed into Ito's stochastic differential equation. The steady-state probability density function of roll motion is obtained, and the results are validated with the numerical simulation and model test.     

DSM-1数字旋转磁力仪技术改进的一种方法

本文介绍的DSM-1数字旋转磁力仪技术改进的方法,是经不断试验、反复修改而成的。实际应用表明:技术改进后的DSM-1数字旋转磁力仪控制系统,其性能及使用功能比原系统有较大的提高,开发的软、硬件适用于所有兼容微机。对进口的DSM系列数字旋转磁力仪控制系统进行技术改进,均可参照此方法进行。     

南沙海区沉积物剩余磁化强度与古气候旋回

根据南沙海区NS87-11柱样沉积物Mr(剩余磁化强度)的变化曲线与δ~(18)O(氧同位素)变化曲线平行对比,发现Mr的波峰、波谷与δ~(18)O揭示的古气候变化的波峰、波谷相对应。表明南沙海区沉积物的Mr记录了暖→冷→暖古气候旋回变化的特征,反映了全球性气候变化的波动周期。微体古生物分析结果可以证实这一特征。这预示海洋沉积物的Mr不仅可作为探索古气候变化的重要标志,而且可能成为第四纪磁性地层对比、划分的依据。     

冲绳海槽沉积物干酪根特征

本文采用元素分析、镜下观察、红外光谱、扫描电镜和热解分析等技术,分析了冲绳海槽柱状样中腐植酸、富里酸和干酪根的化学、物理特征,并探讨了它们之间的成因关系和干酪根类型。沉积物的产烃能力甚差,每吨沉积物仅能生成0.49～1.18kg烃类物质。     

Long-term variations of temperature and salinity of the Bohai Sea and their influence on its ecosystem

Long-term variations of the sea surface salinity (SSS), air temperature (AT) and sea surface temperature (SST) of the Bohai Sea during 1960–1997 were analyzed. They all showed positive trends. The trends of the annual mean SSS, AT and SST of the Bohai Sea were, respectively, 0.074 y⁻¹, 0.024°C y⁻¹ and 0.011°C y⁻¹. The increases of AT and SST were consistent with, the recent warming in northern China, in the Huanghai Sea (Yellow Sea) and in the East China Sea. The rise of SSS can be attributed to the rapid reduction of the total river discharge into the Bohai Sea, as well as to the increase inflow of high salinity water from the Huanghai Sea. It may also be attributed to increasing human use of river water and increases in evaporation from the sea surface. These changes in the marine environment seemed to have important influence on the Bohai Sea ecosystem.     

Characteristic analysis of wind field and sea wave field over the NW Pacific Ocean

The NW Pacific Ocean is not onIy the only transportation way between America andAsia, but also the source influencing on inIand climate and marine variability of adjacentseas in China. Based on ship observation data during l950 - l995 in the NW Pacific,with data from several hundreds to 30 thousand in every 5"x5" grid network, throughanalyzing the monthly mean directions of prevailing wind, wave and swelI, wind speed,pressure, wave height and frequencies of gaIe of 6 and 8 sca1e, high sea…     

一类非线性系统次优控制的灵敏度法

本文研究一类非线性定常系统的次优控制问题。通过在系统中引入 1个灵敏度参数并将系统变量关于灵敏度参数展开 Maclaurin级数 ,使求解最优控制的非线性两点边值问题化为一族线性两点边值问题。利用截取最优控制级数的有限项求得系统的次优控制律。仿真实例表明 ,该方法对非线性系统次优控制律的设计是有效的     

渤海鱼类群落结构特征的研究

根据１９８２－１９８５年和１９９２年８月－１９９３年６月间渤海渔业增殖生态学调查所得的１０９０网次定量资料，运用数理统计的方法，分析鱼类群落结构多样性综合指标的变化特征。结果表明，在１９８２－１９８５年间渤海鱼类鱼种数为１１９种，其中暖温种居首位，占５７．９８％；暖水种次之，占２８．５７％；冷温种种数最少，占１３．４５％。群落结构的季节变化规律呈现单周期型，１０月份鱼种数最多，达８３种；２月份仅为