2×110kW推轮的设计及应用

为适应长江、汉江干支运输,本文设计了2×110KW推（拖）轮,介绍了该轮的主要数据及技术性能,并从船体艉部线型、浮心位置、螺旋桨及振动和噪声等方面作了改进,经使用其技术性能,从纵方式、建造质量等均达到了同类船型的先进水平。     

The viability of pure vegetable oil as an alternative fuel for large ships

Heavy fuels are likely to remain the dominant fuel source for two-stroke, low-speed diesel engines for large ship propulsion for the next decade or more. There is however, potential for increased use of pure vegetable oils (PVO) as an alternative and, by emitting lower levels of several pollutants, this can help the attainment of Annex VI of the MARPOL 73/78 convention aimed at large ships using fuels with less than 4.5% sulphur or 1.5% sulphur in SO_X emission control areas The use of alternative fuels can also influence the attainment of the Kyoto protocol that requires greenhouse gas emissions to be reduced by 5% by 2010 compared to 1990. This paper analyses the physical and chemical properties of various pure vegetable oils as an alternative to heavy fuel oil for large ship propulsion.     

职业中专"1+2"模式办学的探讨

职业中专走灵活多样的办学模式,是职业教育发展的需要,是企业对具有“双证书”技术人才的需要,是社会发展的需要。     

安装边刚度对分动器振动特性的影响

提出一种考虑安装边支撑刚度对结构振动特性影响的分析方法,应用有限元模态分析方法计算分析了某分动器的振动模态。8种不同支撑刚度计算结果对比表明,随着安装边支撑刚度的增大,自然振动频率会随之增大,且对低阶的影响尤为明显;当安装边支撑刚度增加到一定值时,其变化所引起的自然振动频率变化不再明显,自振频率趋近于刚性支撑时结果。     

Al_2O_3/TiO_2的制备及光催化降解吡啶

以钛酸四丁酯为原料,Al2O3为载体,用溶胶-凝胶法制备负载型TiO2,在UV-TiO2体系中对吡啶(PD)进行光催化降解,并研究了将TiO2负载在不同铝源所制备的Al2O3后光催化剂的差异,结果表明:负载型TiO2光催化剂加入量为10mg/40mL,吡啶的光催化降解反应符合一级动力学方程;吡啶中氮转化成氨氮.将TiO2负载在Al2O3上后利用率提高了6倍左右.     

含氟废水处理技术

本文分析了近十年来国内外对含氟废水处理方面的技术研究进展，分别从处理方法、处理工艺和处理药剂等方面进行了较全面的介绍。     

V2控制BUCK变换器建模及控制器优化

根据V^2控制原理，用状态空间平均和线性化方法分别建立BUCK变换器和其控制环的数学模型，求出整个系统的传递函数，并根据优化控制理论对控制环补偿电路的参数进行优化．仿真结果表明，经优化设计的BUCK变换器比根据经验值设计的变换器的响应速度提高约50％，带宽增加约4倍．     

广州地铁2号线车辆电传动控制系统及其应用

介绍了广州地铁2号线车辆电传动控制系统的组成部件、基本原理，并描述了其矢量控制的方式和在车辆中的实际应用方案。     

Zn~(2+)对神经肌接头传递的作用

研究了Zn~(2+)对大鼠离体膈神经膈肌标本和小鸡颈二腹肌标本的作用。实验结果表明,Zn~(2+)对间接刺激神经诱发大鼠膈肌的收缩,诱发小鸡颈二腹肌的收缩均产生浓度依赖性抑制作用。Zn~(2+)不影响膈神经的兴奋和传导,对直接刺激诱发膈肌收缩的抑制作用弱于对间接刺激神经诱发膈肌收缩的抑制。Zn~(2+)不影响小鸡颈二腹肌对Ach的敏感性。说明Zn~(2+)主要作用于突触前膜阻滞神经肌接头的传递。Ca~(2+)、L—半胱氨酸可拮抗Zn~(2+)的阻滞作用。     

Numerical prediction of the dilution process and its biological impacts in CO2 ocean sequestration

 In order to investigate the biological impacts of the ocean sequestration of CO₂ (carbon dioxide), the dilution processes of CO₂ were investigated near injection points in the deep ocean. From a combined fluid-dynamics, chemical, and biological approach, a two-phase computational fluid dynamics (CFD) method with mass transfer was developed to predict droplet plume flow, the dissolution of CO₂ from droplets into seawater, and the advection–diffusion of dissolved CO₂ (DCO₂) in the deep ocean. Changes in pH due to the concentration of DCO₂ were also calculated. In addition, the isomortality concept of Auerbach et al. was incorporated to predict the lethal damage to marine organisms caused by DCO₂. The simulation results suggested that the biological impacts of CO₂ sequestration were insignificant in terms of mortality in both small-scale field experiments and the real-life cases we propose. Received: October 3, 2001 / Accepted: December 14, 2001