环铁试验基地作为铁路行业重要的试验场所,有必要为铁路基于数字底座的数字化赋能转型探索道路,深化数字技术、数据资源与铁路行业的交汇融合,推动智能铁路不断发展突破,驱动铁路高质量发展.对环铁试验基地及数字化建设现状进行分析,总结其存在的不足,结合信息化发展潮流,引入数字环铁概念,从基础层面、能力层面和目标层面进行定位,分析得出数字环铁试验基地的8项核心能力.将感知层、网络层、平台层和应用层集于一身,形成数字环铁一体化服务平台,可支撑全要素、全业务、全场景的数据汇聚,为数字环铁提供基础平台服务和全域数据服务,进一步发挥环铁试验基地在行业科技创新支撑中的重要作用,引领轨道交通发展战略方向,提升铁路运输服务质量、保障运输安全、增强经营管理效率,为我国铁路引领世界铁路科技进步提供支撑,巩固和提升我国高铁在世界的领跑地位.

The paper introduces details of construction of the China comprehensive urban rail transit test track, and analyzes the unique advantages and features of the urban rail test track. The comprehensive test for urban rail transit plays a role of test basis for urban rail equipment certification bodies in China. Test track can provide the complete tests including standstill test, all inspection for line test, and test items as specified in the inspection and testing rules for urban rail vehicle after assembly. The test track also provides the conditions of 5 000 km adjustment test and reliability test, and complete the joint testing and inspection of communication and signaling systems and other technical systems.

物联网理论和技术为转变铁路经济增长方式提供了支撑。从网络经济和网络化物理系统入手,构建包含传感网络、运输网络、信息网络三个基本网络层次的铁路物联网,提出以集散中心和信息中心为网络节点、面向广大用户的物联网运作模式、组建铁路物联网运输联盟方式的实施策略。

Building the digitalized experiment information platform in State Railway Test Center was the foundation of the experiment platform,which could take systematic test,and comprehensive test.The platform could provide information to others and boost productivity.It was analyzed the objectives,the general structure,the main function,and the key technology of the platform.

(112̄0) GaN/InGaN multiple quantum wells (MQWs) were grown on (11̄02) sapphire by metal-organic vapor phase epitaxy. The excitation-intensity-dependent photoluminescence (PL) spectrum of these samples was measured, and no peak shift was observed. This phenomenon was attributed to the absence of piezoelectric field (PEF) along the growth orientation of the (112̄0) face MQWs. Our experimental results showed that PEF was the main reason causing peak blueshift in excitation-intensity-dependent PL spectrum of (0001) InGaN/GaN MQWs. It was expected that fabricating (112̄0) face nitride device should be a method to avoid PEF and get low-threshold, high-quantum-efficiency and stable-emission-wavelength light-emission devices.

Low-temperature-deposited GaN buffer layers with different thicknesses, as-grown or annealed, and GaN epilayers on the buffer layers have been grown by metallorganic vapor phase epitaxy (MOVPE). The crystallographic, morphologic and optical properties of the GaN buffer layers as well as the influence of these properties on the GaN epilayers have been studied. A model is proposed to interpret the most suitable thickness of GaN buffer layer for GaN epilayer on sapphire grown by MOVPE.

Silicon doped GaN films on sapphire have been grown by metallorganic vapor phase epitaxy. It is found that the electron concentration of the films saturates at high dosage of silane dopant. The electrical, optical, crystalline and morphological properties of the films have been studied.

The growth rate GaN buffer layer on sapphire grown by metallorganic vapor phase epitaxy (MOVPE) over the temperature between 500°C to 600°C is studied. The growth rate as measured using laser reflectance is found to be dependent on growth temperature, the molar flow rate of the sources (in this case, trimethylgallium or ammonia) and the input mode of sources into the two-channel reactor. A model on the growth process of GaN buffer layer by MOVPE is proposed to interpret the experimental evidence.

The physical properties of low-temperature-deposited GaN buffer layers with different thicknesses grown by metalorganic vapor-phase epitaxy have been studied. A tentative model for the optimum thickness of buffer layer has been proposed. Heavily Si-doped GaN layers have been grown using silane as the dopant. The electron concentration of Si-doped GaN reached 1.7×1020cm−3 with mobility 30cm2/Vs at room temperature.

The growth rate of GaN buffer layers on sapphire grown by metalorganic vapor-phase epitaxy (MOVPE) in an atmospheric pressure, two-channel reactor was studied. The growth rate, as measured using laser reflectance, was found to be dependent on growth temperature, molar flow rate of the sources (in this case, trimethylgallium and ammonia) and the input configuration of sources into the reactor. A model of the GaN buffer layer growth process by MOVPE is proposed to interpret the experimental evidence.

Sapphire (��-Al2O3) is the substrate widely used in the growth of GaN. The dependence of its etching rate on polishing solution composition and temperature were investigated. The removal of mechanically damaged layer in sapphire was studied by double crystal X-ray diffraction. It is found that the removal rate of sapphire in H2SO4:H3PO4=3:1 mixture is controlled by surface chemical kinetics.

MOCVD-grown Ga xIn 1-xP (x=0.476-0.505) epilayers were characterized by double-crystal X-ray diffraction (DCXD), Hall measurement and Photo-luminescence. It is found that Ga composition decreases a little with increasing V/III ratio at 650��C due to the competition between the formation of GaP and InP. The electron mobility of Ga 0.5In 0.5 P reaches 3300cm 2/(V��s) at 77K. The carrier concentration decreases with increasing growth temperature and V/III ratio. It suggests that Phosphorus (P) vacancies act as donors. At 17 K, the difference between PL peak energy and calculated band-gap energy of GaInP is between 84-113 meV. This is probably related to impurities and ordered structure in GaInP.

GaN is an important semiconductor material operating in the blue light range. GaN epitaxial layer was successfully achieved by MOCVD with TMGa and NH 3 as sources on (0112) ��-Al 2O 3 substrate. The morphorlogical, crystalline, electrical and optical characterizations of the GaN film were investigated. The minimum FWHM of (2110) peak of double crystal X-ray diffraction rocking curve is 16'. Near ultraviolet and visible light are observed by cathode luminescence.

GaSb layers are grown on GaSb substrates; the effects of input partial pressure of trimethylantimony and the V/III ratio are studied. A model of the MOVPE phase diagram for the growth of GaSb and GaAsxSb1-x is developed which assumes thermodynamic equilibrium to be established at the solid-vapor interface.