多几何缩比的水下爆炸试验换算律

受试验场地条件限制,试验设计不得不采用多个几何缩比时,水下爆炸相似律将不再适用.本文从能量角度给出以水下爆炸动响应试验为目标的模型缩比设计换算律,能在一次试验过程中同时获取一次冲击波和气泡二次压力波冲击环境的测值.     

Optimal container ship size: a global cost minimization approach

ABSTRACT

Currently, the best container ship size in a service is determined mainly by the liner operator, considering only the economies of scale of ships. Its external diseconomies to the ports and shippers are usually not considered in the decision-making process, which may reduce the overall efficiency and lead to global nonoptimality. This study incorporates the cost to the shipping companies at the main lines, ports, and feeder services, as well as the external costs to shippers and ports in a hub-and-spoke network, and determines the best ship size and the number of weekly services to minimize the overall costs. The external cost to the shippers in the feeder ports is assumed to be proportional to the feeder cost, and a sensitivity analysis is provided. The maximum container ship size is estimated according to different levels of freight demand. A numerical analysis shows that the optimal size should be smaller than the current biggest container ships in service.     

Revisiting Jiang’s dynamic continuum model for urban cities

Jiang et al. (Jiang, Y.Q., Wong, S.C., Ho, H.W., Zhang, P., Liu, R.X., Sumalee, A., 2011. A dynamic traffic assignment model for a continuum transportation system. Transportation Research Part B 45 (2), 343–363) proposed a predictive continuum dynamic user-optimaDUO-l to investigate the dynamic characteristics of traffic flow and the corresponding route-choice behavior of travelers. Their modeled region is a dense urban city that is arbitrary in shape and has a single central business district (CBD). However, we argue that the model is not well posed due to an inconsistency in the route-choice strategy under certain conditions. To overcome this inconsistency, we revisit the PDUO-C problem, and construct an improved path-choice strategy. The improved model consists of a conservation law to govern the density, in which the flow direction is determined by the improved path-choice strategy, and a Hamilton–Jacobi equation to compute the total travel cost. The simultaneous satisfaction of both equations can be treated as a fixed-point problem. A self-adaptive method of successive averages (MSA) is proposed to solve this fixed-point problem. This method can automatically determine the optimal MSA step size using the least squares approach. Numerical examples are used to demonstrate the effectiveness of the model and the solution algorithm.     

海事部门管理沉船打捞问题研究

文中结合沉船打捞海事管理工作实践与经验,系统分析了海事沉船管理存在的问题,并提出相应的对策和建议,以促进海事沉船科学监管。     

体育道德法律化问题初探

体育的发展要求有效地监督和规制机制,体育道德和体育法律是两种不同类型的调整方法,二者相互区别又相互联系,这使得体育道德的法律化成为可能.体育道德的法律化有一定的现实意义,并有着深厚的法理基础,对其实施不能任意妄为,必须掌握“度”,科学合理的实现有效转换.     

滚动式安全隐患排查机制在海事监管中的运用

滚动式安全隐患排查机制是指运用系统、科学的方法,周期性地对辖区存在的安全隐患进行排查、评估、排序,制定整改措施,消除安全隐患,此机制是海事长效监管机制的重要组成部分。经过近年来运行、实践和探索,明确了海事监管中存在的突出问题和薄弱环节,逐步实现了从被动处理问题到主动引导航运安全健康发展、从过多依靠专项治理向长效管理转变。     

基于任务型的航海英语口语测试体系

任务型测试是语言测试的发展方向。本文分析了任务型口语测试的理论和核心问题,结合航海英语口语的特点,提出建立基于任务型的航海英语口语测试体系,以提高航海英语口语测试的信度和效度,促进航海英语口语教学向培养语言交际能力的方向发展。     

未来国际海事公约的发展趋势与影响

国际海事公约呈现出新的发展趋势,这些新的发展趋势必将对世界海事活动产生直接的影响。文中首先介绍了目前国际海事公约的发展情况,分析了未来国际海事公约的发展趋势及其对世界各国的影响,最后提出了我国应对未来国际海事公约的几点建议。     

积分形式的交通流动量方程及其应用

根据交通流系统所具有的物理量对时间的全导数的积分公式，即系统内物理量对时间的全导数等于控制域内该物理量对时间的偏导数与单位时间经过控制线的该物理量的通量之和，结合质点系动量定理，建立了积分形式的交通流动量方程，即系统内的交通流动量对时间的导数等于作用在系统上的外力的矢量和，计算了控制域内动量随时间的变化率，以此判断其交通状况。     

非市场经济主体与反补贴制度关系研究——以美国反补贴法为视角

非市场经济主体不是一个法律命题,而是源自关贸总协定期间各缔约方的实践.反补贴制度是否适用于非市场经济主体?世贸组织成员之间有不同的标准.美国的反补贴法虽然对此没有明确规定,但是,1984年联邦第二巡回上诉法院在"钾碱案"中的裁决确立了美国反补贴法不适用于非市场经济主体的司法先例.国人曾普遍认为中国的市场经济主体地位被承认之前,世贸组织成员不会对中国采取反补贴措施.最近发生在中美之间的"铜版纸案"和"反倾销与反补贴案"引发了对非市场经济主体实施反补贴制裁是否违反多边贸易协议规定的争议.事实上,补贴与反补贴协议的适用对象并不区分市场经济主体与非市场经济主体.美国的做法没有违反多边贸易协议的规定,而是打破了不向非市场经济主体适用反补贴法的国内司法先例.