岸线变化对天津近岸海域污染物输移扩散影响研究

应用MIKE21数学模型对天津近岸海域潮流场进行数值模拟,同时考虑天津近岸海域5个典型河口污染物输入的影响,计算了大小潮作用下COD输移扩散范嗣,并研究了岸线变化对COD输移扩散范围的影响.结果表明,岸线的变化对北塘口及天津港附近COD的输移扩散有较大影响.岸线变化后,大小潮高低潮时刻对应的0.001 mg/L浓度等值...     

南通船舶海工及配套业推动新兴产业发展战略研究

在促进长三角区域合作的视野下,通过分析研究世界船舶海工及配套业发展特点及南通船舶海工及配套业发展现状,提出南通发展船舶海工配套业推动新兴产业发展的战略思考.     

自动调温阀拆除对柴油机危害的分析

文章叙述了柴油机冷却水自动调温阀的工作原理和调温特性,分析了调温阀拆除后冷却水温的变化及对柴油机性能的影响,并就维修中燃烧室组件的大量更换是否与调温阀的拆除有关进行了探讨。     

基于纸纤维改性的隧道工程透水砂浆性能研究北大核心CSCD

为提出一种适用于隧道初期支护基面找平并且具有一定透水性能的砂浆,将纸纤维加入砂浆试块中对其性能进行改性。通过分析纸纤维的降解原理,并将不同掺量的纸纤维加入砂浆试块中,对其体积密度、吸水率、抗压强度等基本性能指标及微观结构进行测试和分析。由试验结果可知:在碱性环境中,纸纤维具有可降解的性能特点;纸纤维可以使普通砂浆试块的吸水率提升2~3倍,同时也会造成砂浆试块的体积密度和抗压强度降低;对砂浆试块吸水率和抗压强度进行线性拟合后发现其吸水率和抗压强度呈现负相关关系。研究结果表明,通过纸纤维对砂浆进行透水性能的提升是可行的,但是纸纤维掺量对砂浆其他性能的影响还有待进一步研究。     

Insights on disruptions as opportunities for transport policy change

Policy change is characterised as being slow and incremental over long time periods. In discussing a radical shift to a low carbon economy, many researchers identify a need for a more significant and rapid change to transport policy and travel patterns. However, it is not clear what is meant by rapid policy change and what conditions might be needed to support its delivery.Our contention in this paper is that notions of habit and stability dominate thinking about transport trends and the policy responses to them. We limit variability in our data collection and seek to design policies and transport systems that broadly support the continuation of existing practices. This framing of the policy context limits the scale of change deemed plausible and the scope of activities and actions that could be used to effect it.This paper identifies evidence from two sources to support the contention that more radical policy change is possible. First, there is a substantial and on-going churn in household travel behaviour which, harnessed properly over the medium term, could provide the raw material for steering behaviour change. Secondly, there is a growing evidence base analysing significant events at local, regional and national level which highlight how travellers can adapt to major change to network conditions, service availability and social norms. Taken together, we contend that the population is far more adaptable to major change than the policy process currently assumes.Disruptions and the responses to them provide a window on the range of adaptations that are possible (and, given that we can actually observe people carrying them out, could be more widely acceptable) given the current configuration of the transport system. In other words, if we conceptualise the system as one in which disruptions are commonplace, then different policy choices become tractable. Policy change itself can also be seen as a positive disruption, which could open up a raft of new opportunities to align policy implementation with the capacity for change. However, when set against the current framing of stability and habit, disruption can also be a major political embarrassment. We conclude that rather than being inherently problematic, disruption are in fact an opportunity through which to construct a different approach to transport policy that might enable rather than frustrate significant, low carbon change.     

和谐管理理论在施工企业二次经营中的应用

为提高施工企业二次经营水平，对二次经营的概念和范围的界定进行详细阐述，并就和谐管理理论引入到二次经营工作中。在二次经营阶段通过确定项目和谐主题，建立谐则机制和和则机制并进行有效结合，使项目参建人员通过学习相关知识，提高认识，积极开展施工方案优化，有效控制项目成本，优质的完成所承建的工程任务，取得业主和监理单位的认同，为二次经营创造条件。并就开展二次经营组织机构的建立，相关制度、管理办法、管理措施的制定进行阐述。     

单线隧道24 m仰拱栈桥施工技术研究

为了加快单线隧道施工进度,并确定24 m自行式液压栈桥施工流程和工艺,通过对24 m栈桥仰拱施工一次性浇筑、一次性浇筑24 m并加防裂网片、分区段12 m同步施工,3种施工方案进行分析,发现一次性浇筑及增加防裂筋施工工艺会出现仰拱断面开裂,分区段12 m同步浇筑既保证仰拱断面无裂纹,也加快了施工进度。文中同时提出多工作面施工理念,合理加快施工进度;通过微创微改在配套的矮边墙模板上焊接定位卡、堵头板采用钢木混合安装,反坡排水;安装移动水箱和预留水沟槽等工艺。     

西北沙漠戈壁地区混凝土浇筑特殊养护措施费用分析

地处风沙、干旱地区的建设工程,自然环境条件恶劣,混凝土结构物经过浇筑后,需采取特殊养护措施,才能保证工程质量,从而造成费用增加.此文以处于沙漠戈壁地区的LX铁路部分区段为例,就铁路轨道支撑层、道床板和桥梁墩台采用特殊养护措施所需的材料和人工消耗及费用单价进行分析与计算,并与常规养护措施进行比较.说明采取特殊养护措施后相应费用的不足.应研究解决费用增加的方案。     

货车用新型工程塑料心盘衬垫的研究

铁路机车车辆上下心盘的磨耗，是机车车辆一惯性质量问题。解决此问题的有效方法是在上下心盘间配置新型工程塑料制成的车辆心盘衬垫。文章从原因分析入手，解决了理论计算与实际使用中受力的差异，弄清了车辆心盘衬垫在运行状态下受纵向、横向、扭力及动载加速度等因素影响时与材质物性间的关系，从而确立了合理选材、配方设计、结构设计的科学方案。     

Phase change analysis of an underwater glider propelled by the ocean＇s thermal energy

The phase change characteristic of the power source of an underwater glider propelled by the ocean＇s thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process, but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees, the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change, and the slope of the temperature time history curve remains the same. However, the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size, boundary conditions, and the power source＇s cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38ram needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems.