珠江口东南近海海区污损生物研究

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.     

Fatigue Behavior of Plain Concrete Under Biaxial Compression: Experiments and Theoretical Model

The effects of different lateral confinement stress on the fatigue behavior of and cumulative damage to plain concrete are investigated experimentally. Eighty 100 mm x 100 mm x 100 mm specimens of ordinary strength concrete are tested under constant- or variable-amplitude fatigue loading and lateral confinement pressure in two orthogonal directions. A fatigue equation is developed by modifying the classical Aas-Jakobsen S-N equation for taking into account the effect of the confined stress on fatigue strength of plain concrete. The results of variable-amplitude fatigue tests indicate that the linear damage theory proposed by Palmgren and Miner is unreasonable in the biaxial stress state. A nonlinear cumulative damage model that could model the effects of the magnitude and sequence of variable-amplitude fatigue loading and lateral confinement pressure is proposed on the basis of the evolution laws of the residual strains in the longitudinal direction during fatigue tests. The residual fatigue life predic     

麻痹性贝毒毒素研究Ⅰ.塔玛亚历山大藻的麻痹性贝毒毒素对运动神经末梢和全细胞钠离子通道的抑制作用研究

麻痹性贝毒(Paralytic Shellfish Poisoning，PSP)毒素由石房蛤毒素(saxitoxin，STX)及其衍生物组成，目前己发现20余种，在赤潮研究、分子生物学和神经生物学基础研究、医药、军事防化等方面都有应用潜力[其结构、类型和应用见本集刊王云峰等(2003)“麻痹性贝毒毒素的应用研究进展”一文]。由于PSP毒素的稀有来源和国际社会对STX交易的禁止，限制了国内PSP毒素应用及研究的全面深入展开，因此本文作者对PSP毒素进行了制备，并采用不同方法对制备的PSP毒素进行了研究。 PSP毒素能够选择性地可逆抑制可兴奋膜的电压依赖钠离子通道的开放，从而阻止神经冲动的发生和传导，使神经、肌肉丧失兴奋性(Frace et al.，1986；Penzotti et al.，1998)。本文利用神经束膜下记录和全细胞膜片钳技术，报道了从塔玛亚历山大藻(Alexandrium tamarense)中提取的PSP粗毒素对小鼠运动神经末梢膜电流和NG108-15细胞钠离子通道的作用研究结果，并与STX标准毒素的作用结果进行了比较。 NG108-15细胞是由小鼠神经母细胞瘤和大鼠胶质细胞瘤融合的杂交细胞，经分化剂分化后，显示诸+L1196如兴奋性、合成和释放乙酰胆碱、与培养肌细胞形成突触联系等多种神经细胞的基本特性(Hamprcht，1977)和Na+、K+、Ca2+等多种离子通道，已作为神经细胞模型被广泛应用于分析药物对离子通道作用的研究(Enomoto et al.，1992； Docherty et al.，1992；Shi et al.，1993；Hu et al.，1997a；Hu et al.，1997b)；发育出具有Na+内流支持的锋电位(Hamprecht,1977)，该电位是分析作用于膜钠离子通道药物的好材料。     

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

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.     

锯缘青蟹NAGase的催化机理的判断

以p-硝基苯酚-β-D-氨基葡萄糖苷（pNP-NAG）为底物，研究产物类似物：p-羧基苯酚和苯酚对青蟹N-乙酰-β-D-氨基葡萄糖苷酶（NAGase，Ec3．2．1．52）活力的影响．结果表明：p-羧基苯酚和苯酚对该酶有抑制的作用，IC50分别为20．0和100．0mmol／dm^3．p-羧基苯酚和苯酚对酶的抑制均表现为竞争性类型，其抑制常数K1分别为5．03和25．67mmol／dm^3．结合产物N-乙酰-β-D-氨基葡萄糖（NAG）抑制作用表现为反竞争性类型，判断NAGase水解pNP-NAG反应为有序双双反应（Ordered Bi Bi）．     

Mach Effect of Oblique Nonlinear Irregular Waves Interacting with Vertical Walls

Based on Hong‘s theory, previous random models, and a generalized expression suitable for FIT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simulation demonstrate that the wave energy changes with the incidence angle and the distance from the wall. Particularly, the Mach effect and the combined wave spectrum characteristics are analyzed in detail, which are significant in both theory and practice.     

Probabilistic Models for the Probability of Wave Breaking and Whitecap Coverage Based on Kinematic Breaking Criterion

More and more researches show that neither the critical downward acceleration nor the critical slope of water waves is a universal constant. On the contrary, they vary with particular wave conditions. This fact moders the models either for the probability of wave breaking B or for the whitecap coverage W based on these criteria difficult to apply. In this paper and the one which follows we seek to develop models for the prediction of both B and W based on the kinematical criterion. First, several joint probabihstic distribution functions (PDFs) of wave characteristics are derived, based on which the breaking properties B and W are estimated. The estimation is made on the assumption that a wave breaks ff the horizontal velocity of water particles at its crest exceeds the local wave celerity, and whitecapping occurs in regions of fluid where water particles travel faster than the waves. The consequent B and W depend on wave spectral moments of orders 0 to 4.Then the JONSWAP spectrum is used to represent the fetch-limited sea waves in deep water, so as to relate the probahility of wave breaking and the whitecap coverage with wind parameters. To this end, the time-averaging technique proposed by Glazman (1986) is applied to the estimation of the spectral moments involved, and furthermore, the theoretical models are compared with available observations collected from published literature. From the comparison, the averaging time scale is determined. The final models show that the probability of wave breaking as well as the whitecap coverage depends on the dimensionless fetch. The agreement between these models and the database is reasonable.     

Analysis of Dynamic Characteristics of Submarine Free Spanning Pipelines by Complex Damping Method

Considering the effect of the internal flowing fluid and the external marine environmental condition, the differential equation for the vortex-induced vibration (V1V) of the free spanning pipeline is derived and is discretized by the Hermit interpolation function. The free vibration equation with the damping term is solved by the complex damping method for the natural frequency, and then the effect of fluid damping on the natural frequency of the free spanning pipeline is analyzed.The results show that fluid damping has a significant influence on the damped natural frequency of the free spanning pipeline in the lock-in state, while it has little influence when the pipeline is out of the lock-in state. In the meantime,the change of the free span length has the same effect on the damped natural frequency and the undamped natural frequency.     

Optimization Mathematical Model of Pile Forces for Offshore Piled Breasting Dolphins

An optimization mathematical model of the pile forces for piled breasting dolphins in the open sea under various loading conditions is presented. The optimum layout with the well distributed pile forces and the least number of piles is achieved by the multiplier penalty function method. Several engineering cases have been calculated and compared with the result of the conventional design method. It is shown that the number of piles can be reduced at least by 10%—20% and the piles‘ bearing state is improved greatly.     

A Numerical Model of Coastal Processes of Sand Beaches Based on Long-Term Wave Series

A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is presented. Results of the application indicate that the model is sensitive to the order of the input wave data, and that the effects of long-term wave series and the effects of the mean annual wave conditions on the model are different. Instead of a single wave condition, the wave series will make the calibration and the verification of the model more practical and the results of the model more reasonable.