客运专线42号无砟轨道无缝道岔设计方法研究

基于纵横垂向空间耦合模型,对42号无砟轨道无缝道岔钢轨的纵向受力及变形、道岔钢轨的横向变形、无缝道岔允许轨温变化幅度以及限位器的铺设与养护方法等进行深入研究。结果表明:该设计方法对客运专线42号无砟轨道无缝道岔实际铺设情况考虑得较为详尽,能够较为准确的计算道岔尖轨跟端处钢轨横向变形,可对限位器结构的铺设与养护维修提供指导意见,适用于客运专线42号无砟轨道无缝道岔的设计与检算。该设计方法可为客运专线42号无砟轨道无缝道岔的设计与养护维修提供参考。     

芪丹通脉片对急性缺血再灌注大鼠心肌信号转导系统PI3K/Akt和Erk1/2的影响

目的观察中药芪丹通脉片对缺血再灌注大鼠心肌梗死面积、细胞凋亡和细胞信号转导系统中磷脂酰肌醇-3激酶(PI3K)、丝(苏)氨酸激酶(Akt)和细胞外信号调节激酶(Erk1/2)的影响。方法雄性SD大鼠随机分为假手术组、缺血再灌注组(模型组)和芪丹通脉片预处理组。生理盐水或芪丹通脉片灌胃7 d后,大鼠麻醉开胸,结扎冠状动脉前降支40 min,再灌注4 h。伊文氏兰和TTC染色测定心肌梗死范围,计算梗死面积(IS)与缺血区面积(AAR)的比值(%,IS/AAR);TUNEL方法定性和定量检测心肌细胞凋亡指数;Westernblot测定信号蛋白的表达。结果芪丹通脉片组的心肌梗死范围明显小于模型组[(28.8±8.4)%vs.(49.1±10.3)%,P<0.01];其心肌细胞凋亡指数亦显著低于模型组[(11.6±2.3)%vs.(20.3±4.5)%,P<0.01];而其Akt和Erk1/2的磷酸化表达水平增加,与模型组比较分别增加了2.5倍和1.9倍(P<0.01,P<0.05)。结论芪丹通脉片能够抑制缺血再灌注所致的心肌细胞损伤,并影响生存信号通路PI3K/Akt和Erk1/2的活化水平。     

韩国现代F4A42-2型自动变速器电控系统分析

以韩国现代F4A42-2型自动变速器为例,运用专业知识并查阅资料,对该类型自动变速器的组成、功能及诊断进行分析,为现代自动变速器的维修提供便利。     

汽车新型电气系统发展概述

分析车载用电设备增多带来的问题,介绍了42V汽车电气系统和CAN总线网络传输技术的发展和应用情况。     

Does uncertainty make cost-benefit analyses pointless?

Cost-benefit analysis (CBA) is widely used in public decision making on infrastructure investments. However, the demand forecasts, cost estimates, benefit valuations and effect assessments that are conducted as part of CBAs are all subject to various degrees of uncertainty. The question is to what extent CBAs, given such uncertainties, are still useful as a way to prioritize between infrastructure investments, or put differently, how robust the policy conclusions of CBA are with respect to uncertainties. Using simulations based on real data on national infrastructure plans in Sweden and Norway, we study how investment selection and total realized benefits change when decisions are based on CBA assessments subject to several different types of uncertainty. Our results indicate that realized benefits and investment selection are surprisingly insensitive to all studied types of uncertainty, even for high levels of uncertainty. The two types of uncertainty that affect results the most are uncertainties about investment cost and transport demand. Provided that decisions are based on CBA outcomes, reducing uncertainty is still worthwhile, however, because of the huge sums at stake. Even moderate reductions of uncertainties about unit values, investment costs, future demand and project effects may increase the realized benefits infrastructure investment plans by tens or hundreds of million euros. We conclude that, despite the many types of uncertainties, CBA is able to fairly consistently separate the wheat from the chaff and hence contribute to substantially improved infrastructure decisions.     

新一代汽车电气系统——36/42V阀控式铅酸蓄电池

介绍新一代汽车电气系统对电池发展的影响,新型汽车电池的选择程序及36/42V电系的引入;阐述了该电系对电池制造商和汽车制造商所提出的要求。     

Modeling yard crane operators as reinforcement learning agents

Due to the importance of drayage operations, operators at marine container terminals are increasingly looking to reduce the time a truck spends at the terminal to complete a transaction. This study introduces an agent-based approach to model yard cranes for the analysis of truck turn time. The objective of the model is to solve the yard crane scheduling problem (i.e. determining the sequence of drayage trucks to serve to minimize their waiting time). It is accomplished by modeling the yard crane operators as agents that employ reinforcement learning; specifically, q-learning. The proposed agent-based, q-learning model is developed using Netlogo. Experimental results show that the q-learning model is very effective in assisting the yard crane operator to select the next best move. Thus, the proposed q-learning model could potentially be integrated into existing yard management systems to automate the truck selection process and thereby improve yard operations.     

42号CNTT板式道岔铺设施工技术

42号CNTT板式道岔由转辙器、连接段和辙叉三部分组成,线形为复合曲线,具有容许通过速度高、高安全性等特点。以京沪高速铁路徐州东站42号CNTT板式道岔铺设施工为依托,介绍了道岔铺设的工艺流程、钢轨焊接及精调方法,为今后同类工程施工提供了良好的借鉴。     

General statistics of diesel engines’ idle time: Shunting locomotives in industrial sidings in Poland 2009…2013

Shunting locomotive/switcher (AmE)/utilization profiles are analyzed in this paper, in particular on the basis of idle time data collected in nineteen Polish industrial sidings and yards. 40 years old, diesel-electric locomotives are observed during 1000 h. Idle times related to work cycles are analyzed statistically. The percentage of the shunting locomotive daily operating time that the engine is operating at idle amounts to 70% (from 55% to 90%), and average daily idle fuels consumption amounts to 150 l a day (from 90 to 240 l a day).Many European and Asian countries still operate a significant number of similar (ChME3, e.g. S200) old, diesel-electric locomotives (almost 8000 locomotives have been produced), for moving trains over long distances and as shunting locomotives.Observed frequent short idle time periods suggest necessity of widening future scope of idling times’ analysis. Adaptation of Polish rolling stock will be possible using prior general public education about dangerous carcinogens in diesel exhaust smoke and fuel waste related to diesel engines’ idling. Simple simultaneous depiction of diesel engine power time series together with idle time could be used for educational visualization of idling among a wider audience. In the future classical aggregated idle time statistics should be supplemented by models that are more related to the variability of shunting locomotives diesel generator’s power time series, e.g. distribution of frequent short individual idle time cases.     

Estimating demand variables of maritime container transport: An aggregate procedure for the Mediterranean area

Demand variables of maritime container transport (throughput, transhipment and origin–destination flows) may be estimated with freight demand models. As their parameters generally vary both in time and space, models may not be transferable to geographical areas and time periods differing from that for which they are calibrated.