黄河口附近海域化学需氧量和石油烃分布及其关键控制环境因子分析

于2009年12月、2010年5月、2011年9月、2013年5月和2014年10月,在黄河口附近海域进行了5个航次调查,研究了该海域的化学需氧量(COD)和石油烃的分布情况以及季节变化。结果表明,COD整体呈冬季低、春季高的趋势,而石油烃无明显季节变化趋势。平面分布上,春季和秋季COD高值主要分布在靠近黄河口海域。春季和冬季石油烃高值主要位于调查海域的东北部区域。相关分析结果表明盐度、温度、pH、悬浮物、溶解氧及磷酸盐是影响COD的主要环境因素,而石油烃主要受盐度、温度、pH、无机氮、磷酸盐的影响。进一步多元回归分析结果表明,p H、盐度和溶解氧是影响COD的关键因子,温度是影响石油烃的关键因子。     

Numerical simulation of solitary wave scattering by a circular cylinder array

The interaction of a solitary wave with an array of surface-piercing vertical circular cylinders is investigated numerically. The wave motion is modeled by a set of generalized Boussinesq equations. The governing equations are discretized using a finite element method. The numerical model is validated against the experimental data of solitary wave reflection from a vertical wall and solitary wave scattering by a vertical circular cylinder respectively. The predicted wave surface elevation and the wave forces on the cylinder agree well with the experimental data. The numerical model is then employed to study solitary wave scattering by arrays of two circular cylinders and four circular cylinders respectively. The effect of wave direction on the wave forces and the wave runup on the cylinders is quantified.     

人工饲料饲养的对虾肠道菌群和水体细菌区系的研究

对人工饲料饲养的凡纳滨对虾Litopenaeus vannamei成虾肠道菌群组成及其水体细菌区系组成进行了研究.分离纯化后的革兰氏阴性菌鉴定到种的水平.对虾肠道菌群主要由弧菌Vibrio spp.、希瓦氏菌属Shewnella spp.、嗜氢菌属Hydrogenophaga spp.、伯克霍尔德氏菌Burkholderia spp.、气单胞菌Aeromonas spp.、食酸菌Acidovorax spp.和芽孢杆菌Bacillus spp.组成.水体细菌区系主要包括弧菌Vibrio spp.、希瓦氏菌属Shewnella spp.、艾肯菌Empedobacter spp.、无色杆菌Achromobacter spp.和芽孢杆菌Bacillus spp..肠道菌群和水体细菌区系的优势菌是副溶血弧菌Vibrio parahaemolyticus和芽孢杆菌Bacillus spp..利用Shannon-Wiener指数进行多样性分析,发现虾肠道多样性指数（H）和均匀度（J）高于水体细菌区系,而丰度（D）较低.     

Artificial upwelling induced by ocean currents —Theory and experiment

A submerged apparatus, which consists of a buoy, several horizontal contraction and expansion tubes (Venturi-type tubes) and a long pipe, is expected to be used to pump the subsurface sea-water (200–300 meter depth) containing abundant nutrients to surface layer (50–100 m) by the dynamic of ocean currents. i.e. an artificial upwelling without energy cost. A preliminary experiment and analysis are undertaken and shows that the capacity of pumping the nutrient-rich sea-water is worth to build a pilot prototype model.     

水下智能潜器的神经网络运动控制

本文介绍一种基于神经网络的水下智能潜器的运动控制方法，该方法通过在线学习，融控制与滤波为一体。计算机仿真与水池实验验证表明，该方法的控制与滤波性能良好，对环境的学习与适应能力强。该方法事实上可用于一般动力系统的控制。     

Resistant performance of perforation of multi-layered targets using an estimation procedure with marine application

Recently, multi-layered targets have become commonplace in both military and civilian applications, such as marine hulls, armored vehicle bodies, outside structures of bulletproof cars, and aerospace vessels. This paper studies the resistant performance of perforation in multi-layered targets. An estimation procedure is established based on the concepts of the conservation of momentum, impulse-momentum law, and conservation of energy. Experimental results of the test of Almohandes et al. are adopted to check the residual velocity of multi-layered targets. The results of the verification are good in terms of agreement for impact velocities ranging from 700 to 800 m/s, when the ratio of the projectile length to the projectile diameter (i.e. L/D) is 4.2, and the average residual velocity error of single, double- or triple-layered targets range approximately from 4.42 to 8.40%. The ballistic performance is best for the double target when the ratio of the first layer thickness to the total thickness (i.e. t₁/(t₁+t₂)) is about 0.75, and the worse performance occurs when the ratio t₁/(t₁+t₂) is 0.5. An air gap slightly influences the resistant performance of perforation in multi-layered targets. These results may serve as a useful reference for designers.     

A preliminary analysis of arcuate structures-relationship of the island arc and deep-sea trench to the dip angle of Benioff zone

The origin of arcuate islands and deep-sea trenches has been studied for a long time and various interpretations have been proposed. In this paper, some analytical models are put forward from a geometrical viewpoint and then the theoretical dip angles of the underthrusting slabs of circum-Pacific island arcs are computed and compared with those of the Benioff zone. As a result, it is found that the dip angle of the underthrusting slab is one of the main factors determining the curvature of the arcuate structure. The authors consider that this result may contribute to the plate theory.     

低硼氢氧化镁的制备及热分解动力学参数

本文以水合氯化镁、工业氨水为原料制备出了低硼含量的纯度 >99%的氢氧化镁和氧化镁。利用差热 -热重 (DTA- TG)、X-射线衍射 (XRD)、透射电子显微镜 (TEM)等手段 ,对氢氧化镁的热稳定性、相结构、表观状态以及脱水动力学参数进行了分析。结果为 :氢氧化镁以束状纤维和片状粉末共存 ,在 6 2 3K基本完成脱水反应生成氧化镁 ,其脱水反应的表观活化能 E为135 .4 k J· mol-1,指前因子 A为 5 .15× 10 10 ,反应级数 n为 1.10     

I(L)值完全诱导空间

作者引入 I(L)值完全下半连续映射 ,研究其性质。利用 I(L)值完全下半连续映射定义I(L)值完全诱导空间 ,给出 I(L)值完全诱导空间的拓扑基的表达形式 ,证得两个 I(L)值完全诱导空间的映射是连续映射的充分必要条件 ,并建立了乘积空间的 I(L)值完全诱导空间与 I(L)值完全诱导空间的乘积空间的联系     

国外渔具选择性研究进展

为了保护和可持续利用渔业资源 ,渔具选择性的研究在国际上倍受重视。该文以比较作业法中渔具选择性曲线的推导 ,特别是利用扩张 SEL ECT模型推导渔具选择性曲线为例 ,介绍国外渔具选择性研究的最新进展 ,以期作为我国开展这方面研究工作的参考