水下航行体应用鱼类仿生推进技术的试验研究

水下仿生推进技术将是水下航行体推进技术的革命，这种推进方式是仿生学和水下航行体推进结合的产物，突破了传统的螺旋桨推进理论。初步研究了水下航行体仿生推进技术，以及波状摆动推进中C形起动模式使用不同形状尾鳍的流场结构及动力性能。一般可以将尾鳍形状划分为对称与不对称两大类，选择矩形和三角形作为这两类尾鳍的代表，对其进行了流动显示以及力矩和力测量。研究发现，两种尾鳍模型具有截然不同的流场结构：矩形会在翼尖处产生一个主涡环，而三角形会在尖角上下出现两个涡环。不同的尾迹流场结构有着不同的动力学效果。据此对比分析了不同形状的尾鳍在波状摆动推进中各自的优缺点，在此基础上进一步分析了尾鳍形状在实际工程中的应用。     

Wave impact on a horizontal elastic plate

The objective is to find slamming-induced local stresses in the steel or aluminum wetdeck of a multihull vessel. This is studied theoretically by representing the wetdeck as a beam model and accounting for dynamic hydroelastic effects. Two numerical methods are used, one being a simplified asymptotic solution. Satisfactory agreement between the two methods is reported. Experimental drop tests of horizontal elastic plates of steel and aluminum are also reported, and the results from the experiments agree well with the numerical computations. This study reveals, both numerically and experimentally, that slamming-induced local stresses are strongly influenced by dynamic hydroelastic effects. The maximum bending stresses are insensitive to where waves hit, the curvature of the waves, and maximum pressures. Measured maximum pressures are very sensitive to external conditions, and cannot be used as a measure of maximum local bending stresses. A simple procedure for local design stresses due to wetdeck slamming is outlined.     

气缸套支承肩产生裂纹的原因分析及防止措施

针对某型柴油机气缸套支承肩产生裂纹的现象,根据支承肩受力设计原理进行分析,提出相应的防止措施。     

Risk and investment decisions in non-liner shipping

The investment decisions of non-liner shipping firms based on their behaviour towards risk, stochastic demand for capacity, inelastic supply and foregone profits are discussed. These aspects are formalized in a simple stochastic model, which, together with definitions of two broad categories of risk behaviour, is then used to examine and contrast the investment decisions of the two different strategic groups. The analysis shows that the capacity expansions/investments sought by the risk averter and the risk lover will differ under 'normal' circumstances with the risk averter having significantly less capacity than the risk lover. The risk lover will have higher capacity in a volatile market than in a stable market situation. During periods of high capital costs, the investment decisions of the two risk groups tend to be indistinguishable.     

如何编制公路交通施工计划

施工计划是项目开始的首要任务,从如何编制计划进行分析,结合计划的落实与检查,保证工程最终目标的实现.     

高速磁悬浮列车测速定位系统过接缝问题研究

高速磁浮列车长定子轨道的接缝会使测速定位系统相对位置传感器的检测信号产生畸变,并导致牵引设备过流或过压保护甚至烧毁.为消除轨道接缝的影响,测速定位系统使用了两路相对位置传感器.本文依据自适应滤波器原理,设计了一种自适应预测滤波器,根据相对位置传感器输出的历史值对当前输出值进行预测,通过比较预测值与实际观测值判断检测信号是否产生畸变,并以此为基础对两路传感器的信号进行选择与切换.经过仿真验证,这种方法在传感器存在安装误差和干扰的情况下也可以很好的消除因信号畸变带来的不良影响.     

An analysis of decision-making processes in multicultural maritime scenarios

With three research studies recently carried out the pros and cons of multicultural, multilingual crews have given a 'second' food for thought:

• The Seafarers' International Research Centre (SIRC): 'Transnational Seafarer Communities' and the research, 'Finding a balance: companies, seafarers and family life', linked to this [1]. The latter presented in Maritime Policy & Management, no. 1, January-March 2003.
• The Swedish National Maritime Museum (SNMM): Isolde av Singapore [2]. This research and sociological documentation will be reviewed in a later issue of Maritime Policy & Management.
• Horck, J., 'A culturally mixed student body; the WMU experience in fostering future decision makers' [3].

There is a growing conviction among seafarers and persons working in the land-based sector of the maritime industry (including ex-seafarers) that staff onboard and on shore should be prepared to work with crews and groups whose members come from different countries and cultures and speak different languages. The problem, though, is which culture will have to surrender and which will dominate? Will a third culture become the norm for common survival? Perhaps to understand oneself and be knowledgeable about others is a better way to avoid eventual conflicts.

There are nearly no research findings on how a programme should comprise the aims of facilitating comprehension and appreciation of influences, from differences in cultural backgrounds, on group performance and decisions.

This paper reports on the research carried out on students in the Shipping Management and the Maritime Education and Training courses at World Maritime University (WMU). How do post-graduate students holding unlimited certificates of competency, as well as holders of university degrees with experience in the maritime industry and maritime administration, come to a consensus decision?

The findings in this research are discussed in balance with the results from both the SIRC and the SNMM research which is interesting because the results, in some significant issues, are not the same.

A phenomenographic approach has been used to find out that a multicultural group is not free from working problems. Can cultural differences, perhaps, be developed from an assumed hindrance into a catalyst for stimulating national appreciation and cooperation? Perhaps the opposite is true; it might be a bottleneck for improvements in safety as formulated in the STCW95 and the ISM Code.