上海跨国迁移与流动人口的实证研究——以在沪日本人和赴日返沪人员为例

经济全球化推动了人们生产和生活方式、社会关系、文化模式的发展变迁,也使跨国迁移成为越来越频繁的“常态”。本文通过大量的数据和调查资料,以在沪日本和赴日返沪人员为例,对其历史沿革、人口结构、入出境事由、迁移类型和迁移方式、社会支持网络等问题进行了实证研究,并对二者的异同点进行了初步探讨。     

1+X证书制度背景下汽车专业“三教改革”的实施路径

职业院校是高素质技术技能型人才培养的重要基地,随着社会经济的发展,社会对人才的需求也发生了很大变化,要求既能懂技术又能懂生产,学生毕业就能直接上岗。因此,对职业院校的人才培养模式也带来了新的挑战,为了培养出更加符合现代社会发展需要的汽车专业人才,需要依托"1+X"证书制度,积极探索适合职业院校发展的人才培养模式,认真实施"三教改革",培养出高质量的复合型汽车专业人才。     

对国家应对油污染事故若干措施的建议

文章针对我国当前船舶油污立法的状况和船舶油污事故的现状,对国家应采取的相应措施提出建议,以避免船舶油污事故造成的日益严重的影响。     

轮胎式集装箱门式起重机节能技术应用与发展

介绍当前国内外轮胎式集装箱门式起重机(RTG)的节能技术方案,分析RTG"油改电"应用的主要技术特点,指出RTG节能技术的发展方向。     

大跨度岩溶隧道施工工法比选

随着我国高速公路的发展,在岩溶地区修建隧道工程日益增多,选择合理施工工法是隧道施工安全稳定的重要一环。根据大跨度岩溶隧道中溶腔的发育程度、发育位置以及溶腔内充填物性质的不同,隧道需采用不同施工工法。以乐昌至广州高速公路段某大跨度岩溶隧道为例,采用有限元软件对其进行了三台阶法、单侧壁导坑法和双侧壁导坑法等3种施工工法的比选。最后得出结论：双侧壁导坑法在岩溶隧道施工中能有效的控制围岩塑性区的发展和洞周位移,并且能够有效改善围岩的受力状态,适当提高衬砌的应力水平,是较为合理的施工工法。可为岩溶地区高速公路隧道设计施工提供一定的参考。     

Multi-objective optimization study on dimensions of medium-sized cruise ship in concept phase北大核心CSCD

［Objective］Aiming at the problem of too many influencing factors and too little reference data for determining the dimensions of medium-sized cruise ships in the concept phase, a simplified multi-objective optimization method based on the fitting of dimensions and performance is proposed. ［Method］First, the dimension relations of medium-sized cruise ships are analyzed and the influence of the latest SOLAS requirements used to determine the optimization range. Second, the influence of cruise ship dimensions on space, resistance, stability and seakeeping are analyzed. Next, based on the principles of genetic algorithms, a multiobjective optimization algorithm with high robustness and high engineering adaptability is determined to establish a multi-objective optimization model for the concept design of medium-sized cruise ships. Finally, the Pareto solution obtained by multi-objective optimization is analyzed to provide initial references for determining the dimensions of the target cruise ship. ［Results］Implemented via a genetic algorithm, the optimization program proposed herein is applied in the concept design of a medium-sized cruise ship in order to optimize the initial dimensions, thereby achieving the expected outcome of providing reasonable initial dimensions for cruise ship design. ［Conclusion ］ The proposed simplified multi-objective optimization model can provide feasible initial dimensions for medium-sized cruise ships in the concept phase. As the Pareto solution obtained by multi-objective optimization has different focuses such as resistance and stability, the most suitable solution needs to be selected according to the design object. © 2023 Chinese Journal of Ship Research. All rights reserved.