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61.
62.
为了给沿海地区在役混凝土桥梁的耐久性研究提供更加可靠的理论依据,针对影响沿海地区混凝土桥梁耐久性的主要因素——氯离子侵蚀引起钢筋的锈蚀,从氯离子扩散的角度出发,综合各国氯离子扩散的相关数学模型,提出考虑荷载影响因子和氯离子结合能力这2种因素的混凝土氯离子扩散修正模型,并借助于各国相关的试验数据对氯离子扩散修正模型进行了验证和分析。研究结果表明:与传统的仅考虑单一影响因素的氯离子扩散模型相比,所提出的氯离子扩散修正模型更加合理,可以更准确地预测沿海地区在役混凝土桥梁的剩余使用寿命。 相似文献
63.
耙绞联合施工工艺是一项新兴的疏浚技术,耙吸式挖泥船和绞吸式挖泥船施工能力的合理匹配,在保证施工连续性、发挥耙绞联合施工的最大效率中起到了至关重要的作用。以黄骅港内航道耙绞联合施工为对象,进行耙绞联合施工能力匹配计算分析,并在实际工程中取得了良好的效益。 相似文献
64.
半实物仿真试验是验证导弹制导系统性能的重要手段。为了验证模型导弹雷达导引头的抗干扰性能,设计了基于RT-LAB仿真环境的半实物仿真系统。介绍了RT-LAB仿真系统架构,阐述了系统构成和仿真模型构建过程,给出了导引头抗干扰半实物仿真方法和评估指标。研究表明,基于RT-LAB的半实物仿真系统构建方便快捷、建模难度小,可显著提高仿真系统的稳定性和可靠性。 相似文献
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66.
Over the last few decades, many developing countries have experienced car fleet growth, which has contributed to congestion, increased travel times, and deteriorated public transport reliability and punctuality. However, alternatives to urban mobility can be found by creating policies to stimulate sustainable transportation modes with equal opportunities for all citizens. In this paper, measures of social effective speeds are presented to improve sustainable urban mobility policies in developing countries. Data from the 2018 Origin-Destination Survey of the Metropolitan Region of Recife (Brazil) were used to estimate social effective speeds. The results showed that motorized modes had lower effective speed than non-motorized modes. In addition, total external costs were $2 billion USD per year. The social effective speed will be valuable if inserted in sustainable urban mobility policies in developing countries. 相似文献
67.
建筑结构识图和钢筋算量是高职土建类专业学生的核心技能之一。通过聚焦"专业岗位职务能力",对课程重新定位,结合工作岗位任务进行教学内容选取并实施综合考核方式,使学生的知识技能更加贴合专业岗位需求,并实现学生学习热情的长效性,让学生更加适应市场需求,取得了较好的教学效果。 相似文献
68.
Significant effects of traffic congestion include the cost associated with extra travel time, fuel consumption, and gas emissions. This paper develops a mathematical function to quantify the monetary impact of transition designs between signal timing plans on users and the environment. This function offers an approach to reduce problems such as excessive travel time, pollution emissions and fuel consumption. The proposed social cost function is evaluated for various transition plans to assess the impact of the number of steps required to adjust signal timing. The relationships between delay, fuel consumption and gas emissions and the number of steps needed to achieve the transition are also analysed. 相似文献
69.
This paper examines the time-use patterns of adults in dual-earner households with and without children as a function of several individual and household socio-demographics and employment characteristics. A disaggregate activity purpose classification including both in-home and out-of-home activity pursuits is used because of the travel demand relevance of out-of-home pursuits, as well as to examine both mobility-related and general time-use related social exclusion and time poverty issues. The study uses the Nested Multiple Discrete Continuous Extreme Value (MDCNEV) model, which recognizes that time-decisions entail the choice of participating in one or more activity purposes along with the amount of time to invest in each chosen activity purpose, and allows generic correlation structures to account for common unobserved factors that might impact the choice of multiple alternatives. The 2010 American Time Use Survey (ATUS) data is used for the empirical analysis. A major finding of the study is that the presence of a child in dual-earner households not only leads to a reduction in in-home non-work activity participation (excluding child care activities) but also a substantially larger decrease in out-of-home non-work activity participation (excluding child care and shopping activities), suggesting a higher level of mobility-related social exclusion relative to overall time-use social exclusion. To summarize, the results in the paper underscore the importance of considering household structure in activity-based travel demand models, as well as re-designing work policies in the United States to facilitate a reduction in work-family conflict in dual-earner families. 相似文献
70.
马克思对"人的价值"之类命题的批判 总被引:1,自引:0,他引:1
卢炜 《上海交通大学学报(哲学社会科学版)》2004,12(6):57-60,68
马克思认为:“人的价值”之类的命题在本质上是资本主义经济的思想反映。因而,它决非是关于人的本性、尊严和幸福的永恒观念,而仅仅是资产阶级的特殊要求、愿望和幻想的反映。它同共产主义的世界观是根本对立的。在共产主义社会中,新的命题“每一个人的自由发展”将取代陈腐的命题“人的价值”。 相似文献