Drag Coefficient,Dynamic Roughness and Reference Wind Speed

Surface waves are the roughness element of the ocean surface. The parameterization of the drag coefficient of the ocean surface is simplified by referencing to wind speed at an elevation proportional to the characteristic wavelength. The dynamic roughness is analytically related to the drag coefficient. Under the assumption of fetch limited wave growth condition, various empirical functions of the dynamic roughness can be converted to equivalent expressions for comparison. For datasets covering a wide range of the dimensionless frequency (inverse wave age), it is important to account for the variable rate of wave development at different wave ages. As a result, the dependence of the Charnock parameter on wave age is nonmonotonic. Finally, the analysis presented here suggests that the significant wave steepness is a sensitive property of the ocean surface and a single variable normalization of the dynamic roughness using a wavelength or wave height parameter actually produces more robust functions than bi-variable normalizations using wave height and wave slope.     

全数字十二相稳压稳流微机控制系统

提出用于十二相可控整流器的８０９８单片机控制系统的电路原理和软件策略。包括自适应控制算法和触发相序计算在内的多种操作全部用软件实现．与通常的方法相比，此系统的成本更低，动态性能和静态性能更好。     

高效铝合金牺牲阳极的研究

在铝中添加合金元素Zn,Mg,In,Ga,Ca,利用正交设计方法,研制出一种高效的铝合金牺牲阳极,它在海水中的电流效率达95.6％,电位为-1.09V(SCE)。并研究了合金元素In,Ga,Ca对铝合金电化学性能的影响及阳极活化机理。     

吉尼系数的计算及正态分布的吉尼系数

本文给出了吉尼系数的一般计算公式 ,推导出正态分布的吉尼系数渐进无偏估计 ,并以实例对比了传统的吉尼系数的算法——万分法与本文中提出的估计方法。     

温度、体重和摄食水平对花尾胡椒鲷幼鱼粪便比能值及吸收率的影响

鱼类没有消化的食物通过粪便而排出体外.没有消化的食物、黏液、消化道脱落细胞、代谢酶以及细菌等就组成了鱼类的粪便.排粪后所保留的食物能可以通过吸收率来估算,其计算式为:A=C-FC/C×100%,式中A(吸收率)以百分数表示;C(摄食量)等于摄入的食物质量乘以食物比能值;F(粪便排出量)等于排出的粪便质量乘以粪便比能值.吸收率在营养学上又称为消化率.粪便比能值的测定在计算吸收率时是非常必要的,但在以往对鱼类吸收率的研究[1～6]中,由于粪便收集的困难及粪便的样品量通常很少,均没有对不同条件下鱼类所排出粪便的比能值进行单独的测定.     

Experimental study of reflection coefficient and wave forces acting on perforated caisson

The reflection coefficient and the total horizontal forces of regular waves acting on theperforated caisson are experimentally investigated. The empirical relationship between reflection coefficient and the ratio of the total horizontal forces acting on the perforated caisson to those on solid vertical walls with the relative chamber width, relative water depth and porosity of perforated wall, etc. are given. Moreover, the results of the ratio of the total horizontal forces are also compared with formulas given by Chinese Harbour Design Criteria and Takahashi, which may be useful for the practical engineering application.     

红色无硫细菌处理高浓度鱼品废水的研究

本文从城市生活污水的沉降污泥中分离出三株红色无硫细菌,经鉴定R1为胶质红假单胞菌(Rhodopscudomonas gelatinosa),R2为沼泽红假单胞菌(R palustris)、RS-1为红螺属(Rhodosprillum)的一种。R1与R2均为兼性需氧和兼性光能利用菌,RS-1为专性厌氧光合菌。作者提出了它们的主要生理、生化特性和最适生长条件,最后确定R1、R2是较有利用前途的优势种类。作者利用上述分离的菌株对高浓度的鱼品废水进行了净化处理试验,得出R1对CODcr的去除率约为65％,R2的去除率为74％以上。二者混合使用可提高至87％。作者还发现废水中的非光合性杂生菌有助于提高光合细菌的净化力。     

Simulation of wave power devices

Classical frequency and time domain models of a single degree of freedom wave power device are presented. In the time domain, a convolution integral is conventionally used to represent the fluid dynamic radiation force, characterised by added mass and damping in the frequency domain. This integral is replaced by an approximate ordinary differential equation (ODE) model which is faster and more convenient in simulations. A time domain model of the fluid dynamics of an oscillating water column (OWC) device is derived to illustrate the technique. Digital simulations of the OWC are used to compare the accuracy of the classical and ODE models. The simulation of the ODE model runs about six times as fast as the classical model based on convolution, yet characterises the fluid dynamics accurately.     

使用简易测试平台检测马哈克扭力仪的性能

本文描述简易测试平台的原理与制作，对马哈克MAIHAK MDS－820型扭力仪检测模拟负载的准确性进行探讨。     

考虑底摩擦的波浪折射计算

本文用考虑底摩擦的折射模式计算了浅水中波高和波向分布。作为一个例子,根据不同的摩擦系数和不同的边界条件计算了一种简单海底地形的折射系数、衰减系数和折射角,所得结果与不考虑底摩擦的折射模式结果进行比较,发展它们之间存在一些差异,表明在浅水中底摩擦对波高有一定影响。