Research on digital twin technology and its application in intelligent operation and maintenance of highspeed railway infrastructure

Purpose–This paper analyzes the application of digital twin technology in the field of intelligent operation and maintenance of high-speed railway infrastructure from the perspective of top-level design.Design/methodology/approach–This paper provides a comprehensive overview of the definition,connotations,characteristics and key technologies of digital twin technology.It also conducts a thorough analysis of the current state of digital twin applications,with a particular focus on the overall requirements for intelligent operation and maintenance of high-speed railway infrastructure.Using the Jinan Yellow River Bridge on the Beijing–Shanghai high-speed railway as a case study,the paper details the construction process of the twin system from the perspectives of system architecture,theoretical definition,model construction and platform design.Findings–Digital twin technology can play an important role in the whole life cycle management,fault prediction and condition monitoring in the field of high-speed rail operation and maintenance.Digital twin technology is of great significance to improve the intelligent level of high-speed railway operation and management.Originality/value–This paper systematically summarizes the main components of digital twin railway.The general framework of the digital twin bridge is given,and its application in the field of intelligent operation and maintenance is prospected.

Development of High-Speed On-Of Valves and Their Applications

With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components is critical in the digital hydraulic technology.High-speed on-of valves(HSVs)which convert a train of input pulses into the fast and accurate switching between the on and of states belong to widely used basic digital hydraulic elements.In some ways,the characteristics of the HSVs determine the performance of the digital hydraulic systems.This paper discusses the development of HSVs and their applications.First,the HSVs with innovative structures which is classifed into direct drive valves and pilot operated valves are discussed,with the emphasis on their performance.Then,an overview of HSVs with intelligent materials is presented with considering of the switching frequency and fow capacity.Finally,the applications of the HSVs are reviewed,including digital hydraulic components with the integration of the HSVs and digital hydraulic systems controlled by the HSVs.

Digital Transformation:Reshaping China’s Development Landscape

The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap the benefits of digitalization.For China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual circulations.Crowded out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized sectors.New capital,industries and technology clusters emerge as new drivers of manufacturing and service sector development.With its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.

A survey of high-speed high-resolution current steering DACs

Digital to analog converters(DAC)play an important role as a bridge connecting the analog world and the digital world.With the rapid development of wireless communication,wideband digital radar,and other emerging technologies,better performing high-speed high-resolution DACs are required.In those applications,signal bandwidth and high-frequency linearity often limited by data converters are the bottleneck of the system.This article reviews the state-of-the-art technologies of high-speed and high-resolution DACs reported in recent years.Comparisons are made between different architectures,circuit implementations and calibration techniques along with the figure of merit(FoM)results.

Mirror-assisted multi-view high-speed digital image correlation for dual-surface dynamic deformation measurement

Based on the recently proposed mirror-assisted multi-view digital image correlation(MV-DIC),we establish a cost-effective and easy-to-implement mirror-assisted multi-view high-speed digital image correlation(MVHS-DIC)method and explore its applications for dual-surface full-field dynamic deformation measurement.In contrast to the general requirement of four expensive high-speed cameras for dual-surface dynamic deformation field measurement,the established mirror-assisted MVHS-DIC halves the cost by involving only two synchronized high-speed cameras and two planar mirrors.The two synchronized high-speed cameras can dynamically measure the front and rear surfaces of a sheet sample simultaneously through the reflection of the two mirrors.The results on the two surfaces are then transformed into the same coordinate system,leading to the required dual-surface 3D dynamical deformation fields.The effectiveness and accuracy of the established system are validated through modal tests of a cantilever aluminum sheet.The vibration measurement of a drum and dual-surface transient deformation measurement of a smartphone in the drop-collision process further prove its practicability.Benefiting from the attractive advantages of multi-view dynamic deformation measurement in a cost-efficient way,the established mirror-assisted MVHS-DIC is expected to encourage more comprehensive dynamic mechanical behavior characterization of regular-sized materials and structures in vibration and impact engineering fields.

Algorithm implementation of high-speed laser g yro signal demodulation filter

Based on the characteristics of field-programmable gate array(FPGA) such as multi-task,high-speed,parallelity,etc,a filtering algorithm is presented to filter the output signal of laser gyr o with high-speed and high accuracy.The filter is composed of basic logic cell s,multipliers an d memory inside FPGA.By using an multiplication decomposition method and design ing reliable time-sequence,the filter is realized,which is easy to be transpl anted and of low cost.Furthermore,all the signal demodulation algorithms of t he laser gyr oscope can be integrated in only one FPGA,which reduces the cost and complexity of the system.

数字赋能“有效论”:数字化转型对重污染企业绿色创新的双向效应

当前,以大数据、云计算等为代表的数字技术快速发展,为企业绿色创新提供了新动能。然而,数字赋能的“有效性”问题一直在学术界存在争议。基于2010—2020年中国沪深A股重污染企业数据,实证检验了数字化转型对企业绿色创新的影响及作用机制。研究发现,数字化转型与绿色创新之间存在显著的倒“U”型关系,且样本企业广泛分布于倒“U”型曲线最高点的左侧;管控投入在数字化转型与企业绿色创新的关系中发挥部分中介作用。同时,政府补助能够显著强化数字化转型与企业绿色创新之间的倒“U”型关系。异质性分析表明,上述倒“U”型关系主要存在于国有企业和媒体报道较多的企业中。这说明,“技术驱动”有助于重污染企业绿色创新“增量提质”,但过度数字化会诱使企业陷入“技术鸿沟”,不利于数字化与绿色创新的协同推进。因此,重污染企业应找准数字技术赋能生态环境保护的契合点与着力点,政府可以利用补贴政策进一步激励企业数字赋能绿色创新。

基于数字孪生技术的桩机姿态与工况监测系统

针对振动式打桩机操作人员视野受阻、桩体姿态监测困难、无法实时监控桩机运行工况等问题,提出一种基于数字孪生技术的桩机姿态与工况监测系统。建立反映当前状态的桩体姿态偏摆预警模型,通过分析预警模型实现对桩体偏摆预警并做出调整提示。同时监测系统还包括桩机工况监测模块、桩体姿态监测模块与虚拟模型驱动模块,实现对桩机运行数据的实时采集与传输,并建立三维动态界面,解决了传统沉桩视野受阻难题,提高了桩机的沉桩精度与工作效率。

Design and Realization of a Monolithic GaAs 3Bit Phase Digitizing DAC

Design,realization,and test of a monolithic GaAs 3bit phase digitizing DAC for 3bit digital radio-frequency memory are detailedly described.The 0.5μm fully ion-implanted GaAs MESFET is used to fabricate the circuit in Nanjing Electronic Devices Institute’s (NEDI’s) 75mm standard process line.The high-speed DAC is designed with on-wafer 50Ω I/O impedance matching.Test results show that its work bandwidth is more than 1.5GHz,and phase accuracy is better than 4%.Its code conversion rate can be higher than 12Gbps.

安全驾驶能力养成的数字化技术应用研究

数字化技术的发展应用正深刻影响着驾培驾考行业的发展模式,也为实现培训与考试的有效对接、推进驾驶训练过程监管提供了数据支撑,对于创新安全驾驶能力培养模式具有重要意义。本文立足当下数字化转型背景,研究分析安全驾驶能力培养在培训、考试、驾车环节存在的突出问题,结合数字化技术的发展特点和应用效果,分别从驾驶行为数字化分析、考试过程数字化评判、培训过程数字化监管提出前瞻性思考,探究安全驾驶能力养成的数字化创新发展新路径。

数字基础设施促进山东新旧动能转换的机制研究

本文旨在研究数字基础设施对山东省新旧动能转换的影响,通过相关理论分析和实证检验发现:(1)数字基础设施促进了山东省新旧动能转换;(2)机制分析检验显示,技术创新与人力资本结构高级化是数字基础设施建设促进山东新旧动能转换的重要路径。这为数字基础设施建设促进山东新旧动能转换的发展提供了理论参考和以下政策启示:加大对数字基础设施建设的投入,积极落实“宽带中国”试点城市政策;增强技术创新能力,促进数字基础设施建设的发展;加大教育投入,提升地方人力资本水平。

数字阀控制拨叉式蝶阀开闭执行器设计

液压数字阀控制拨叉式蝶阀开闭执行器主要研究了产品原理、设计了产品结构,并进行了数学模型分析,总结了产品特点和产品应用。独特的数字阀技术应用,为行业的研究提供了一种全新的技术方案。

基于无感FOC的一体式无刷电机控制驱动器的电路系统

针对无感方波控制时,存在控制精度低,电流采样误差大,低速启动性能较差等问题。设计了一种基于无感FOC的一体式无刷电机控制驱动器的电路系统。系统以TI公司的大电流栅极驱动器DRV8301为预驱核心,设计了数模耦合电路及高端电流采样电路,实现了控制器和驱动器的高度集成,减少了电流采样误差。经实验测试表明,所设计的电路系统能够实现FOC正弦波的稳定输出,持续输出功率可达上千瓦,实时电流监测误差不超过1%,具有体积小、高爆发、高精度控制、响应速度快等优点,可广泛用于工业自动化控制等领域。

Measuring the kinetic parameters of saltating sand grains using a high-speed digital camera

A high-speed digital camera is used to record the saltation of three sand samples(diameter range:300–500,200–300 and100–125μm).This is followed by an overlapping particle tracking algorithm to reconstruct the saltating trajectory and the differential scheme to abstract the kinetic parameters of saltating grains.The velocity results confirm the propagating feature of saltation in maintaining near-face aeolian sand transport.Moreover,the acceleration of saltating sand grains was obtained directly from the reconstructed trajectory,and the results reveal that the climbing stage of the saltating trajectory represents an critical process of energy transfer while the sand grains travel through air.

High-speed playback of spatiotemporal division multiplexing holographic 3D video stored in a solid-state drive using a digital micromirror device

We propose a high-speed playback method for the spatiotemporal division multiplexing electroholographic three-dimensional(3D)video stored in a solid-state drive(SSD)using a digital micromirror device.The spatiotemporal division multiplexing electroholography prevents deterioration in the reconstructed 3D video from a 3D object comprising many object points.In the proposed method,the stored data is remarkably reduced using the packing technique,and the computer-generated holograms are played back at high speed.Consequently,we successfully reconstructed a clear 3D video of a 3D object comprising approximately 1,100,000 points at 60 frames per second by reducing the reading time of the stored data from an SSD.

Design of large memory TFT LCD driver based on Verilog language

This paper presents a design scheme of SDRAM controller based on FPGA. The paper analyze the basic operation principle of SDRAM, and introduce the state machine and the arbitration mechanism. Simulation verification in QuartuslI development environment using Verilog language show that the system achieve high-speed data caching and transmission. The design method of each module and the realization process in the overall design is introduced in detail. The experimental results show that： the controller design is flexible, stable and reliable operation, low cost. can be used as IP core for the cache system in different SOC_

数据要素新动能对制造业高质量发展的影响研究

研究数据要素新动能对制造业高质量发展的影响效应及作用机理,对于突破传统动力弱化所导致的发展约束,推进经济社会高质量发展具有重要现实意义。基于制造业高质量发展的“驱动力—压力—状态—影响—响应”(DPSIR)评价指标体系,对2008—2019年中国31个省份的制造业高质量发展指数进行熵值处理,运用面板Tobit模型,检验数据要素新动能对制造业高质量发展的影响效应。结果显示:中国制造业高质量发展指数呈现“稳步提升”的发展趋势,子系统差异显著;制造业高质量发展指数呈现“东部地区>西部地区>中部地区”的分布格局,东部地区领先优势较为明显,地区差异呈现“先升后降”的演变趋势。数据要素对中国制造业高质量发展具有显著的促进作用,但区域异质性特征明显,西部地区数据要素新动能对制造业高质量发展具有显著的促进作用,而东部地区和中部地区的影响不显著。全国视角下的财政投入、城镇化发展、外商投资、电力消耗对制造业高质量发展具有正向作用,而工业化水平、技术市场规模、地区开放和科技改进的作用相反。分地区视角下,城镇化水平和电力消耗对东部、中部及西部地区的制造业高质量发展均有正向作用,工业化水平则对三大地区的制造业高质量发展均存在抑制效应,技术市场规模、企业信息化、外商投资、地区开放和科技改进对三大地区的影响皆不相同。最后,从数据要素的权属界定、要素流动、高效利用和安全保护等方面,围绕深化数据要素新动能对制造业高质量发展的促进效应提出相关政策建议。

数字劳动秩序的构建、消解与调节——一项基于传统巡游出租车司机的考察

平台经济蓬勃发展并将彻底颠覆诸多传统行业的规则,传统行业中的常规劳动者群体正处在新旧秩序交替之间的特殊过渡期。通过聚集中国长三角地区超大、特大城市的传统巡游出租车司机群体,以这一群体的媒介化生活为实践田野,借助建构型扎根理论方法阐释这种处于两种经济形态过渡地带的数字劳动秩序何以构建。研究表明,平台通过任务分派、规则指导和绩效评估形成了劳动秩序建构的主导性力量;而司机群体借由选择性接单、技术盗用、平台脱媒和自我脱离,与劳动秩序中的不平等权力关系形成对峙;技术想象与规则认同是司机在平台劳动场景之下存有的积极动因,身份妥协和规则迎合则是他们在平台劳动场景之下维持工作信念的支撑力所在。

高性价比的LED驱动及按键扫描电路与算法设计——以8段数码管显示驱动控制电路为例

针对LED数码管控制和多按键扫描方法的不足,提出一种高性价比且易于实现的新算法,以8段数码管显示驱动控制电路为例完善设计与算法。该算法扫描周期为20ms,在每只数码管动态显示的2.5ms内,同时进行8个按键扫描。电路通过74HC164芯片进行扩展,还可以驱动16只或24只数码管以及扫描相应数量的按键输入,算法简单,硬件成本低廉,可在车站、机场、银行、医院等公共场所推广使用。

整合与适应:巡游出租车司机的数字平台驯化实践

伴随着网络预约出行平台和传统巡游出租车的融合,数字平台成为一种外来技术开始进入巡游出租车司机的日常劳动过程。本研究基于驯化理论框架,对67位巡游出租车司机进行了观察和半结构化访谈,并对巡游出租车司机的3个社交群聊进行了参与式观察,探究了处于平台经济形态与传统工作状态交界处的司机群体对数字平台的驯化过程。研究发现,巡游出租车司机借助技术想象与意义建构勾连接入动机,调整工作时间与空间以完成技术的物质嵌入,通过知识共享与情感共鸣实现身份共同体的重塑。巡游出租车司机对数字平台的驯化实践呈现出技术融入生活过程中的整合与适应特征,是对经典劳动过程理论中二元对立框架的回应与延展。