电气化铁道牵引变压器寿命评估

讨论牵引变压器的温升与寿命损失及其相关内容，分析影响变压器寿命的因素，归纳分析变压器运行状况和使用寿命的方法，并通过分析计算估计出给定变压器的实际寿命。     

Mortality through ontogeny of soft-bottom marine invertebrates with planktonic larvae

The present survey covers one spawning season of marine benthic invertebrates in a large geographical area, the inner Danish waters, and includes a wide range of habitats with steep salinity and nutrient load gradients. The loss ratios of soft-bottom marine invertebrates from one development stage to the next is calculated based on average abundances of pelagic larvae, benthic post-larvae and adults of Bivalvia, Gastropoda, Polychaeta and Echinodermata, with planktonic development. This gives a rough estimate of the larval and post-larval mortality. Loss ratios between post-larvae stage and adult stage (post-larval mortality) varies from 3:1 to 7:1 (71.2–84.9%) and loss ratios between larvae and post-larvae (larval mortality) and between larvae and adult, ranging from 7:1 to 42:1 (85.2–97.6%) and from 45:1 to 210:1 (97.8–99.5%), respectively. The results show a remarkable unity in loss ratios (mortality) between the mollusc taxa (Bivalvia and Gastropoda) at the phylum/class level. This similarity in loss ratios among the mollusc taxa exhibiting the same developmental pathways suggests that the mortality is governed by the same biotic and abiotic factors. Larval mortality is estimated to range from 0.10 d^− 1 to 0.32 d^− 1 for Bivalvia and ranging from 0.09 d^− 1 to 0.23 d^− 1 for Polychaeta. The species loss ratios combined with specific knowledge of the reproduction cycles give estimated loss ratios (mortality) between the post-larvae and the adult stage of 25:1 and 14:1 for the bivalves Abra spp. and Mysella bidentata. For the polychaete Pygospio elegans the loss ratio (larval mortality) between the larvae and the post-larval stage is 154:1 and between the post-larvae and the adult stage 41:1. For Pholoe inornata the loss ratio between post-larvae and adults is 7:1. The present results confirm that the larval stage, metamorphosis and settlement are the critical phase in terms of mortality in the life cycle for Bivalvia. Assuming steady state based on actual measurements of pelagic larval densities an estimated input to the water column of pelagic bivalve larvae is ranging from 10,930 to 17,157 larvae m^− 2 d^− 1 and for Polychaeta between 2544 and 3994 larvae m^− 2 d^− 1. These estimates seem to correspond to the reproductive capacity of the observed adult densities using life-table values from the literature.The potential settlement of post-larvae is 43 post-larvae m^− 2 d^− 1 for Bivalvia and 56 post-larvae m^− 2 d^− 1 for Polychaeta. The adult turnover time for Bivalvia is estimated to be 1.5 years and 2.1 years for Polychaeta. This exemplifies that species with short generation times may dominate in very dynamic transitional zones with a high frequency of catastrophic events like the frequent incidents of hypoxia in the inner Danish waters.     

影响施工机械经济寿命计算因素的探讨

施工机械经济寿命的计算，是施工机械更新决策中确定其最佳更新期的一个重要方法．本文针对影响施工机械经济寿命计算准确性的有关因素，分析其产生的原因，提出了利用率修正系数、币值变动修正系数和无形磨损引起的相对经济寿命的三种修正方法，并运用实例进行了计算、分析。     

The lurch towards formalisation: Lessons from the implementation of BRT in Johannesburg,South Africa

The City of Johannesburg, South Africa, implemented the first phase of its Bus Rapid Transit (BRT) system named Rea Vaya between 2009 and 2011. The system design and organisational arrangements drew heavily on precedents from South America, especially insofar as BRT is used as an instrument for securing the transformation and formalisation of a fragmented and problematic informal public transport industry. Despite the inevitable transition problems, the formalisation scheme appears to be generally successful – an outcome that surprised many analysts as it follows a long history of mistrust, resistance, and unsuccessful interventions between government and the minibus taxi industry. The paper offers an analysis of the reasons for the successful transformation of participating taxi operators, by using a life-cycle analogy. We argue that the minibus-taxi industry in South Africa has reached a state of stasis and maturity, with limited opportunities for further growth in its present form. BRT, as it is implemented locally, offers opportunities for re-invention – for moving onto new a potential growth trajectory – by overcoming the binding constraints of informality and by opening up new markets to operators. The life-cycle analysis also offers some insights into critical success factors that, if not met in the long run, could jeopardise the longevity and scalability of the formalisation project. The paper concludes with insights regarding the planning and management of BRT systems to maximise their potential for leveraging the formalisation of informal operators, both in South Africa and in other developing countries.     

辽宁高速公路预防性养护维修工程应用效果总结

对高速公路采用预防性养护能够长期保持路面良好的服务水平,具有显著的社会效益;应用费用寿命周期分析法对预防性、改正性养护方案进行对比分析,结果表明预防性养护可以节省大量的维修资金。     

提高制动主缸寿命的设计改进

文章从设计角度阐述了提高制动主缸寿命的方法。改进方法主要有缸体阳极氧化处理、补偿孔反冲工艺、活塞结构设计、活塞倒角改圆设计、皮碗圆角设计5个方面,通过对缸体、活塞、皮碗的结构和工艺加工方法等细节方面的改进,提高了整个制动主缸的耐久性,并通过试验数据证明了改进的效果。改进后的主缸耐久性得到了全面提高,使制动主缸的寿命延长,同时提高了整车的使用性能。     

运输模式选择的计量分析与实证研究

选择何种内陆运输模式对区域经济发展和集约型社会的构建具有重要意义。文章出于循环经济与绿色交通的战略构想，从环境、经济、运输时间、便捷性、土地节约化利用、安全等方面对内河航运和公路运输进行综合比较分析，构建内陆运输模式选择的指标体系。引入模糊综合评价法对2种内陆运输模式进行综合评价，为内陆地区综合运输体系的构建提供参考。以江苏省南北向交通为例进行了实证分析，并对内河航运的发展提出相关建议。     

铁道标准全寿命信息管理系统

铁道标准及技术文件管理平台由铁道标准全寿命信息管理系统、铁道标准及技术文件信息查询系统、技术文件信息管理系统构成。介绍铁道标准全寿命信息管理系统的管理范围、数据构成、工作流程、管理与服务功能等内容。     

有轨电车运营模式与运输能力研究

在我国多个城市有轨电车的建设与运营过程中,系统运输能力及其提高措施难以确定。结合国内外已运营线路的经验与新线设计中的模拟分析,对有轨电车运营模式、运输能力以及服务标准进行研究,探讨运输能力影响因素与关键技术标准,提出在半专用路权、路口开放的线路条件下,有轨电车的运营模式应灵活设置,路口控制周期控制在150 s以内,最小发车间隔在高峰时段建议3～6 min,舒适度标准建议采用5～6人/㎡的站席标准;提出优化有轨电车运输能力的措施,如行车计划与信号优先系统匹配、提高有轨电车在封闭区间的运行速度等。     

铁路运输房建设备大修维修周期的探 讨简

随着高速铁路建设的发展,许多新材料、新设备应用于铁路运输房屋建筑,而房建设备大修维修周期还是沿用《铁路房屋建筑物大修维修规则》,已满足不了当前新设备的维修要求。故此文在阐述房建设备大修维修周期现状及存在不足的基础上,对修订或制定新的铁路运输房建设备大修维修周期的必要性进行探讨。通过分析与探讨,对编制完成的《铁路运输房建设备大修维修规程》送审稿中有关大修维修周期的内容进行介绍。