Scheme of Railway 5G Integrated Innovation Test Platform

An inevitable trend has already taken shape for the application of the 5th Generation Mobile Communication Technology(5G)in the railway sector.The application scenarios and business types of the railway sector are complex and diverse,so it is indispensable to test and verify the railway 5G before actual deployment.The design and creation of the railway 5G integrated innovation test platform provides engineering design,test and verification conditions for the networking,coverage and business development of 5G public networks and 5G-R in railway scenarios.This paper introduces the design of the overall architecture for the integrated railway 5G innovation test platform according to the railway network requirements,application scenarios and intelligent development trend;respectively elaborates on the design of the 5G-R core network,bearer network and wireless access along loop tracks,in combination with the characteristics of railway scenarios and the requirements of railway dispatching,operation and safety;raises further solutions on the network deployment and coverage schemes of 5G public networks so as to meet the application requirements of 5G public networks.The study results show that the integrated railway 5G innovation test platform scheme contains co-existence of 5G public and private networks,combines the indoor and outdoor scenarios,as well as takes into account of the dynamic and static tests so as to meet the environmental requirements for the integrated railway 5G test and application of all network functions,for which it can provide comprehensive technical support for railway 5G technology research and development,standard formulation,testing,etc.

Carrying Railway 5G Service Application by Multi-technology Convergence

The application scenarios of railway radio communication are complex,while the existing narrowband communication such as GSM-R and radio train dispatching system fails to meet the requirements of service application development.The carrying capacity of railway 5G-R has been greatly improved,mainly for wide-area train-ground communication services such as dispatching communication,train control and train operation safety monitoring.However,for large passenger stations,freight yards,maintenance bases and other places with densely populated railway operators,it is unable to carry overall railway service applications limited by the spectrum bandwidth of 5G private networks,so it is necessary to consider various radio technologies for supplementation.This paper also elaborates the railway service application scenarios,analyzes the characteristics of radio communication technologies such as 5G mmWave and the 6th-generation wireless LAN technology(Wi-Fi6),and discusses the schemes of multi-technology convergence carrying railway 5G service applications.

Tackling Key Technological Problems and Advancing 5G Technology Application in Railway

The paper summarizes the development of mobile communication of domestic and foreign railways,and proposes the priorities for tackling key technological problems of railway 5G private network according to the technical routes of railway next-generation mobile communication determined by China State Railway Group Co.,Ltd.From the aspects of work objectives,principles,technical routes and innovative working methods,the paper elaborates the ideas of railway 5G scientific and technological research,puts forward the contents and plans of scientific and technological research on railway 5G private network,systematically organizes the achievements in the scientific and technological research stage of railway 5G private network,and sets forth the key contents of next-step scientific and technological research.

V对H13型压铸模具钢相变特性的影响

本研究采用热膨胀仪测定了不同钒(V)含量的H13型压铸模具钢的连续冷却转变(Continuous cooling transformation,CCT)曲线及等温转变(Time temperature transformation,TTT)曲线,并结合扫描电镜、显微硬度仪、X射线衍射仪分别探究了V元素含量对H13型压铸模具钢相变点(加热过程中珠光体转变为奥氏体的温度A c1,加热过程中渗碳体和碳化物完全溶入奥氏体的温度A ccm和奥氏体化后冷却过程中奥氏体向马氏体转变开始温度M s)、连续冷却转变规律、等温转变规律以及硬度的影响。结果表明:随着V元素含量的增加,试样的M s点升高,CCT和TTT曲线中的珠光体及贝氏体相区出现左移,CCT曲线中珠光体和贝氏体相区的临界冷却速度加快,试样的淬火态硬度降低。这主要是因为随着V含量的升高,试样中形成了更多稳定的V系碳化物,从而降低了奥氏体化过程中溶入基体的碳含量,进而降低了过冷奥氏体的稳定性,最终促进珠光体及贝氏体相变的发生,即CCT和TTT曲线中珠光体及贝氏体相区左移。

4Cr5Mo2V钢曲轴热锻模具失效分析

采用光学显微镜(OM)、扫描电镜(SEM)和能谱仪(EDS)对失效曲轴热锻模具的心部、裂纹处及基体的夹杂物、强韧性和显微组织进行表征与分析,从而阐明模具开裂的原因。结果表明:该模具由4Cr5Mo2V钢制成,模具开裂主要是由组织不均匀和热疲劳引起的,心部组织在淬火时未完全淬透,导致心部存在贝氏体组织,从而产生较大的内应力,而热疲劳进一步加速裂纹拓展,最终导致模具过早失效。