A Practical Approach of Developing Mathematical Model for All Speed Governors

The paper introduced a special approach for diesel’s all-speed-governor modeling, which, in some cases, could solve the knotty problem frequently met in computer simulation of diesel propulsion system or diesel generating set. Suppose that it is hard to get a control-oriented governor mathematical model when the general approaches, the analytical approach or the experimental approach, are applied, and that an open-loop step response of the diesel engine and its system is available by means of computer simulation, the critical three parameters of a governor mathematical model, the proportional gain K_p, integral time constant K_i, and derivative time constant K_d, can be determined by use of PID tuning method which are widely applied in industrial process control. This paper discussed the train of thought of the approach, precondition, procedure, several modifications of the classical PID model, and some points for attention. A couple of case studies were given to demonstrate the effectiveness of this approach.

MODELING AND IMPLEMENTATION OF SPEED GOVERNOR FOR THE HYBRID ELECTRIC VEHICLE ENGINE

A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.

The clinical application of Governor moxibustion in China

Governor moxibustion is a type of external treatment in traditional Chinese medicine that remains being little understood This article briefly describes the current status, limitations, and future development of the clinical application of Governor moxibustion, to facilitate its use in treatment and health care

Buffer Occupancy of Double-Buffer Traffic Shaper in Real-Time Multimedia Applications across Slow-Speed Links

In this paper, a double-buffer traffic shaper was investigated to adjust video frame rate inflow into the TCP sender-buffer of a multimedia application source across a slow-speed link. In order to guarantee QoS across a slow-speed link (i.e. 1 MBPS), the double-buffer traffic shaper was developed. In this paper, the buffer size dynamics of double-buffer was investigated. The arrival and departure of frames were modeled as a stochastic process. The transition matrix for the process was generated and the stationary probability computed. A simulation program was written in Matlab 7.0 to monitor the buffer fullness of the second buffer when a 3600 seconds H.263 encoder trace data was used as test data. In the second buffer, it was discovered that over 90% of the play-time, the buffer occupancy was upper bounded at 300 frames per second and utilization maintained below 30%.

The Application of China's High Speed Railway Earthquake Early Warning System in Jakarta-Bandung HSR

Earthquake has a significant impact on operation safety of the high speed railway,and for Jakarta-Bandung High Speed Railway(HSR)in Indonesia where it is earthquake-prone,it is necessary to establish an earthquake early warning system to strengthen its earthquake resistance.Based on the principle and technical characteristics of China's high speed railway earthquake early warning system and combining the actual situations of Jakarta-Bandung HSR in Indonesia,this paper describes how to implement China's high speed railway earthquake early warning system in Jakarta-Bandung HSR.It focuses on optimizations in environmental adaptation design and seismic network interface design,earthquake attenuation model parameter adjustment and terminal software interface adjustment,so as to make the system better suit the local situations,and meet operation requirements and guarantee safe operation of Jakarta-Bandung HSR.

Design and application of a multi - function combined hydraulic oil cylinder

Hydraulic equipment in engineering, in different working stages, different speed, load, variable load and variable speed is one of the most frequently encountered problems, to solve this problem is usually used to continuously adjustable pressure, adjustable flow control to achieve. In this paper, the structure design of a combination of oil tanks, combined with oil circuit examples in the case of no need to adjust the pressure, adjust the flow rate, to achieve the high speed, light load of the typical operating requirements and hydraulic servo feedback.

Application and development of friction stir welding technology in high speed EMU manufacturing

The application status of friction stir welding technology is introduced,and the application research of advanced FSW technology in the manufacture of high-speed electric multiple unit aluminum alloy body is analyzed,including the application of traditional friction stir welding technology to a combination of a lap joint and butt joint,and butt joint of large thick plate by both sides process,also introduces bobbin-tool friction stir welding to a butt joint and three-dimensional space curved friction stir welding to T-joint. At the same time the future development trend of new FSW technology derived from traditional FSW technology in rail vehicle manufacturing industry is put forward. As the fast developing of critical technology used on railway vehicles,quick applying advanced welding technology will affect products quality,manufacturing cost and production cycle time directly,and it certainly will be one of the approaches to develop markets by all the railway vehicles manufacturing enterprises.

Study on the technologies development trend of high speed EMUs

High speed railway technologies are rapidly development in the world.The total distance of the high speed railway is more than 40,000 kilometers in China,and many types of high speed Electrical Multi-Units(EMUs)are operated.The top operation velocity of the train reaches 350 km/h.New science and technologies are developing rapidly.New generation technologies such as the information technology,intelligent manufacturing,new material and processing,innovating design philosophy have revolutionary influence on the high speed train.It promotes the high speed train performance such as intelligence,reliable operation and environment-friendly.Based on many years investigation of the trend of the technology development and requirement of general public,the trend of technology development in five aspects are presented in this paper.The five aspects include economic applicability,high speed and high efficiency,green and low carbon,intelligent safety,comfortable and high quality.

零速信号在机车电气控制中的应用

随着机车电气控制技术的不断发展,零速信号在机车电气控制中扮演着重要的角色,零速信号是指机车制动或牵引系统中用来检测车辆是否处于零速状态的信号,它能够帮助系统实时监测车辆的运行状态,从而实现精确的控制和调节,文章探讨了零速信号在机车电气控制中的应用,希望能够为机车电气的控制发展提供借鉴。

变速抽水蓄能机组功率优先控制模式的运行稳定域分析

变速机组相较于传统定速机组在运行和调节中具有快速、高效、灵活和可靠等优点。然而变速抽水蓄能电站刚刚起步,其在有功功率调节过程中的运行稳定性需要进一步研究。本文中基于MATLAB和Simulink作为主要工具研究变速抽水蓄能电站在有功功率调节中的动态稳定性。首先,建立了一个变速抽水蓄能电站的水-机-电耦合的数学模型。然后,建立13阶状态矩阵用于理论研究系统的动态稳定性,并进行时域模拟进一步验证和分析,验证了理论矩阵和数学模型的有效性和合理性。结果表明,变速抽水蓄能机组在并网条件下的有功功率调节的过程中,可能面临失去稳定性的风险,这是定速机组不会出现的新问题。因此,在变速抽水蓄能电站的设计和运行过程中,需要重点关注系统特性参数与控制参数的匹配问题。研究结果可为提高变速抽水蓄能电站调节稳定性提供技术参考。

高速受电弓安装形式对列车气动性能的影响

受电弓作为高速列车上不可或缺的部件,其结构特性直接影响高速列车整车气动性能。采用数值仿真方法,基于三维稳态SST k-ω模型,分析高速受电弓不同安装形式对高速列车气动性能的影响以及各节车辆气动阻力的变化规律,并进一步研究其横风环境适应性。研究结果表明:当高速列车在明线运行时,高速受电弓不同安装形式对整车气动性能影响较小,但受电弓所在车辆的气动阻力变化较大;与闭口-升前弓工况相比,受电弓开口-升前弓时整车气动阻力减小2.10%,其中第6节车气动阻力减小6.06%;在横风条件下,受电弓开口-升前弓时整车横风稳定性能较优,与开口-升后弓工况相比,整车横向力与倾覆力矩分别降低2.52%和3.48%,其中第6节车横向力和倾覆力矩分别减少11.13%与18.50%。因此,在明线有无横风条件下,受电弓安装形式为开口-升前弓的气动性能均最优,且升前弓能改善受电弓后区域的流场结构,从而达到改善整车气动性能的目的。

高速磁浮轨道功能件适用范围分析

研究目的:为探明高速磁浮轨道功能件拟合曲线线路时所产生轨道形位偏差的规律,指导高速磁浮轨道功能件的设计、选型,提升磁浮线路的拟合效果,满足高速磁浮线路高平顺性的要求,建立功能件拟合曲线线路的几何模型,探究不同曲线半径工况下功能件的功能面的位置、偏转值的理论偏差变化规律,提出功能件的适用范围。研究结论:(1)功能件在曲线段的拟合效果与功能件的长度、定子排列方式、导向面曲率半径、曲线线路参数有关;功能件长度越短、曲线半径越大拟合效果越好,定子径向(折曲)排列曲线拟合效果优于定子直线排列,带有曲率半径导向面对改善小半径平面曲线的拟合效果明显;(2)2.064 m、3.096 m、6.192 m长的定子直线(折曲)排列的功能件能够拟合的竖曲线半径应分别大于1900 m(950 m)、2800 m(950 m)、5700 m(1950 m),直线型、R=790 m和R=1550 m导向面的功能件,在平面曲线半径分别为∞、790 m、1550 m的线路上拟合效果最优;(3)本研究成果可为功能件的设计/选型、施工误差控制、优化功能件拟合磁浮线路的效果等提供参考。

针对高速车辆线性稳定性的等效锥度运用限值确定方法

为制定合理的轮轨匹配等效锥度运用范围,避免高速车辆出现蛇行失稳现象,提出一种基于模态分析的轮轨匹配等效锥度合理运用限值确定方法。首先,基于车辆系统动力学理论,建立包含21个自由度的高速车辆系统横向动力学模型;其次,采用模态分析计算车辆系统模态参数(模态频率、阻尼比和振型),并提出基于最小模态距离的蛇行频率连续跟踪算法;然后,利用车辆系统模态最小阻尼比判断模态振型,对轮轨匹配等效锥度和速度进行协同变参计算,确定等效锥度运用限值;最后,从模态视角研究车体蛇行失稳的发生机制。结果表明:在广域轮轨匹配关系下,转向架蛇行失稳和车体蛇行失稳区域均具有清晰的边界,且二者不邻接;对于车体蛇行失稳而言,频率耦合不是唯一决定因素,频率耦合速度也是决定因素之一,当频率耦合发生在较高速度下时易发生车体蛇行失稳。采用该方法,确定所构建的高速车辆模型在350 km·h^(-1)车速下的等效锥度运用限值为0.07~0.41。

高拉速连铸中间包耐材防护优化与应用

高拉速浇钢会造成中间包较严重的冲刷侵蚀,为进一步实现连铸高效率生产,满足高拉速长寿命中间包要求,通过优化中间包冲击区和迎钢面修砌方式、Al_(2)O_(3)-MgO护板材质、永久层预埋冲击板、稳流器安装方式等防护技术,提高在高拉速工况下中间包的使用寿命和安全系数。在小方坯连铸机4.5 m/min的高拉速工况下,中间包使用寿命由20 h提高到45 h,使连铸机具备长寿命高拉速的生产能力,实现了连铸直供棒材轧制生产的工艺条件,满足连铸浇注周期与轧制品种、设备维护相匹配的工艺要求。

高速逆流色谱法分离脂肪酸的应用

脂肪酸在动植物油脂及风味食品中广泛存在,部分不饱和脂肪酸因具有良好的降血脂、抗氧化活性而备受关注。由于脂肪酸大多以甘油三酯的形式存在于天然食品中,需经过精制分离后才能利用,而传统分离手段纯化得到的脂肪酸纯度低,难以满足高纯度脂肪酸的消费需求。高速逆流色谱法是一种无固态支撑的液-液色谱技术,具有无不可逆吸附、单次进样量大等优势,近年来已被广泛用于天然产物的分离纯化。文章结合近年来国内外相关研究工作,比较了高速逆流色谱法与传统分离技术的优缺点,对高速逆流色谱分离脂肪酸的溶剂体系、洗脱模式、常用检测器及其实际应用进行综述,并对其应用前景进行展望,旨在为高速逆流色谱在脂肪酸分离纯化的应用提供参考。

赖氏通元针法诊治耳鸣经验

耳鸣是临床难治疾病,且发病率高。赖氏通元针法认为,耳鸣不外虚实两端,虚者与神元关系密切,实者与外感六淫、痰湿血瘀以及气滞阳郁等病理因素相关。通元针法以神元为本、以任督二脉为总纲、以调节阴阳为大法、注重局部与整体相结合,并且强调补泻运用,具有扶正祛邪、固本培元的临床疗效。临床应用上通过“通督养神”法发挥心脑养神,温助阳气的作用;“引气归元”法起培元固本,调畅气机的功效;配合随证而治,使邪去正安。气血生化有源并正常上荣于耳窍,从而有效缓解患者的耳鸣症状。该文总结并分析了赖新生教授运用通元针法诊治耳鸣的经验,为临床应用提供新的针灸治疗方案。

科技管理视角下5G技术创新与应用

5G技术的出现以及快速发展,不仅有效改变我们的生活方式,还对各行各业转型发展产生巨大影响。作为一种新兴技术,5G技术虽然在国家科技发展战略中占据重要位置,但是依旧处于探索阶段,在各行各业中的实际应用中还存在一定的薄弱环节。物流行业与人们日常生活及社会发展等都具有密切联系,为实现物流行业的转型升级,应注重5G技术的创新应用。该文以科技管理视角下5G技术创新与应用为研究对象,从物流行业入手,在分析物流行业发展现状的基础上,探讨5G技术在物流行业的应用优势。最后,提出科技管理视角下物流行业对5G技术创新与应用策略,期望可以为相关工作的优化提供理论参考和更多思路。

基于Uni-app框架的高中物理实验App设计——以加速度传感器为例

基于Uni-app框架自主开发了高中物理实验App软件,详细阐述了基于手机传感器的App开发流程,并基于此实现了电梯加速度测量实验,讨论了气垫导轨测量重力加速度的实验过程,实验结果与理论值相符.与Phyphox软件进行对比发现:二者采集的实验数据吻合度较高.该自主软件的开发流程和实验过程描述,将为基于智能手机实验的App开发提供技术参考.

应用于高速图像传感器的高线性度Latch ADC

针对高速应用设备对CMOS图像传感器高速、高线性度的要求,本文在传统SS ADC(Single Slope ADC,单斜模数转换器)的基础上,实现了一款应用于图像传感器的Latch ADC,工作频率达到了600 MHz。Latch ADC可以多列像素共用一个Gray Code计数器,并通过Latch结构快速锁定和存储数据,实现了SS ADC中Counter和SRAM的功能。本文采用110 nm工艺,实现了一种高速12位Latch ADC。经过仿真验证,本文的Latch ADC具有高线性度,每次转换的周期为7.094μs,平均功率为180.3μW,转换功耗为1.279 nJ.

铁路综合交通枢纽工程信息化及BIM应用现状与展望

我国铁路“十四五”发展规划对于全面推进铁路高质量发展提出了明确要求,特别是在现代铁路综合交通枢纽工程建设方面设定了一系列新的目标和任务。BIM技术作为铁路工程信息化的主要发展方向,能够有力推动铁路综合交通枢纽工程建设,实现高质量发展。归纳铁路综合交通枢纽在建设过程中的关键BIM应用需求,详细阐述当前我国高速铁路综合交通枢纽在智能设计、智能施工、智能管理、智能运维4个方面开展的BIM应用,验证信息化及BIM技术能够有力推动铁路综合交通枢纽工程在全生命周期实现精细化、协同化、智能化发展,并对我国高速铁路综合交通枢纽工程信息化及BIM技术的发展前景进行展望。