ALTERABLE INTERVAL OPTICALELECTRONIC AUTOCOLLIMATION METHOD FOR STRAIGHTNESS MEASUREMENT OF PRECISION GUIDE

Optical-electronic autocollimation method is commonly used to measure straightness of precision guides in engineering application. However, the traditional fixed interval optical-electronic autocollimation method is not suitable for measuring straightness of an air-bearing guide with a long air-bearing bush or a precision straight guide with a long slide-carriage, because the air-bearing bush and the slidecarriage are actually taken as a big bridgeboard bigger than the length of the bridgeboard with the reflector, which is about 1/4-1/2 of total length of the measured guide. If straightness is measured according to the traditional method, only a few points are sampled so that the guide straightness can not be evaluated fully or accurately. In order to solve the problem, an alterable measuring interval method is proposed for straightness measurement based on analyzing the mutual relations and effects among the tilting angle of the reflector, the length of the bridgeboard, the measuring interval and the straightness of the guide. A straightness calculation model is also developed using the method, and the errors stemming from the method proposed are introduced in brief. A precision air-bearing guide with a long air-bearing bush is measured and evaluated using the method proposed, and the actual measurement and evaluation results prove that the method is correct in theory and practical in operation. The method proposed gives an effective and flexible solution to the straightness measurement of the precision guide with long slide-carriage or air-bearing bush in application. It is an extension of the traditional optical-electronic autocollimation method for straightness measurement.

Characterization of relativistic electrons generated by a cone guiding laser pulse

We demonstrated the interaction of a gold cone target with a femto second（fs） laser pulse above the relativistic intensity of 1.37×10 18 μm 2 W/cm 2.Relativistic electrons with energy above 2 MeV were observed.A 25%-40% increase of the electron temperature is achieved compared to the case when a plane gold target is used.The electron temperature increase results from the guiding of the laser beam at the tip and the intense quasistatic magnetic field in the cone geometry.The behavior of the relativistic electrons is verified in our 2D-PIC simulations.

4-12 Electron Beam Guiding by Grooved SiO2 Parallel Plates without Energy Loss

Since the unexpected guiding effect of low energy ions by PET nanocapillaries was reported in the last decade[1], the self-organized charge-up on insulating surface is employed to realize a self-adaptive manipulation of charged particle beams[2–4]. Considerable work (see Ref. [5] and references therein) has been done to investigate slow highly charged ions (SHCIs) interacting with inner surface of various insulating capillaries[5].

4-20 Electrons Guiding through a Plate Capillary

The guiding effect of 3 keV Ne7+ ions passing through an insulating PET nanocapillaries was found in 2002by N. Stolterfoht et al[1]. Since then considerable work[2] has been done to investigate slow highly charged ions(HCIs) interacting with inner surfaces of various insulating capillaries. It has been shown that the guiding effect isprevalent in the transmission of slow HCIs.Similar guiding phenomena were also observed for electrons transmitted through capillaries (see, e.g., Ref. [3-5]).However, the experiments showed that transmission efficiency of electrons was significantly lower than that of HCIs.Moreover, it revealed that portion of the transmitted electrons suffered significant energy-loss.

Three-dimensional simulation of long-wavelength free-electron lasers with helical wiggler and ion-channel guiding

A three-dimensional simulation of a steady-state amplifier model of a long-wavelength free-electron laser （FEL） with realizable helical wiggler and ion-channel guiding is presented. The set of coupled nonlinear differential equations for electron orbits and fields of TE 11 mode in a cylindrical waveguide are solved numerically by the Runge–Kutta algorithm with averages calculated by the Gaussian quadrature technique. Self-fields and space-charge effects are neglected, and the electron beam is assumed to be cold and slippage is ignored. The parameters correspond to the Compton regime. Evolution of the radiation power and growth rate along the wiggler is studied. Ion-channel density is chosen to obtain optimum efficiency. Simulations are preformed for the FEL operating in the neighborhood of 35 GHz and 16.5 GHz for the electron beam energies of 250 keV and 400 keV, respectively. The result of the saturated efficiency was found to be in good agreement with the simple estimation based on the phase-trapping model.

Intense laser beam guiding in self-induced electron cavitation channel in underdense plasmas

In underdense plasmas, the transverse ponderomotive force of an intense laser beam with Ganssian transverse profile expels electrons radially, and it can lead to an electron cavitstion. An improved cavitation model with charge conservation constraint is applied to the determination of the width of the electron cavity. The envelope equation for spot size derived by using source-dependent expansion method is extended to including the electron cavity. The condition for self-guiding is given and illuminated by an effective potential for the laser spot size. The effects of the laser power, plasma density and energy dissipation on the self-guiding condition are discussed.

Characterization of relativistic electrons generated by a cone guiding laser pulse

We demonstrated the interaction of a gold cone target with a femto second(fs) laser pulse above the relativistic intensity of 1.37×10 18 μm 2 W/cm 2.Relativistic electrons with energy above 2 MeV were observed.A 25%-40% increase of the electron temperature is achieved compared to the case when a plane gold target is used.The electron temperature increase results from the guiding of the laser beam at the tip and the intense quasistatic magnetic field in the cone geometry.The behavior of the relativistic electrons is verified in our 2D-PIC simulations.

基于KANO-QFD模型的电子产品导购APP设计研究

为了能够更好地使电子产品导购APP有针对性地满足用户需求,提升用户满意度,文章提出了基于KANO-QFD模型的电子产品导购APP设计研究。首先,对KANO模型与QFD模型进行概述,并对电子产品导购APP现状进行分析;其次,提出基于KANO-QFD的电子产品导购APP设计思路,即对用户进行调研,并将调研结果代入KANO模型,得出电子产品导购APP的需求属性和每个属性的重要程度数值,同时通过QFD模型进一步获取设计要求权重,对设计要求的优先级进行排序;最后,将设计要求优先级转化为设计策略。通过文章的研究,以期能够为相关设计提供一定参考。

农机农艺融合的高效割胶技术优化设计与应用

割胶是橡胶树收获胶乳的重要途径,便携式机械化割胶是实现产业升级和节本增效的途径之一。为进一步提高机械割胶效果,根据采胶生理特殊性、割胶工况复杂多变性、橡胶树收获物胶乳黏弹特性、橡胶树生长差异性、割胶形式多样性等农机农艺融合问题对割胶机械的设计需求,优化设计便携式电动割胶装备的切割刀片、电子调速器、导向器等零部件。优化结果表明:采用刃高≥10 mm的刀片割胶,可以轻松切断旧胶线;电子调速器在电机转速为3 201~8 459 r/min区间调速时,灵敏度高,单次割胶轨迹连续平稳;导向器形状从“L”型优化为“T”型,减少旧胶线对割胶机械的干预。优化后的技术,提高便携式割胶机械对割胶农艺的适应性,降低操作技术难度和单株割胶时间,胶工更容易快速掌握。

经济型电子导向胶轮系统应用研究探讨

目前城市轨道交通行业高速发展,大运量城市轨道交通市场已趋于成熟,随着国家审批政策的转变,中低运量已成为城市轨道交通未来的发展方向。在低运量城市轨道交通领域,电子导向胶轮系统作为一种采用虚拟轨道运行的新型交通制式,具备运量大、准时正点、RAMS水平高、节能环保、维护成本低以及部署灵活等优点。文章以既有产品为基础,结合审批政策对低运量系统的要求,对市场需求、运营模式、线路规划、系统配置等顶层技术指标以及全寿命周期成本等进行分析研究,并提出一套全面而经济的电子导向胶轮系统方案,旨在为城市交通行业提供一套切实可行的经济型电子导向胶轮系统解决方案。

电子导向胶轮系统特点及发展分析

电子导向胶轮系统是近年来我国轨道交通体系中出现的新成员,为我国轨道交通建设提供了新思路、新模式。首先,分析电子导向胶轮系统与传统轨道交通在导向模式上的区别,介绍光学导向和磁导航2种导向模式的技术原理;其次,进一步分析该系统在运能、速度、选线、路面结构、建设成本、建设周期方面的特点;随后,结合现阶段电子导向胶轮系统在株洲、宜宾、上海、盐城的应用案例,总结其功能定位,指出应重点在大城市地铁线路已连接但覆盖面积不足的区域以及有建设需求的中小城市中积极推广该系统;最后,结合现阶段的建设运营经验,针对该系统未来的发展提出6点建议,以期为后续的建设工作提供参考。

电子导向胶轮电车的车体侧翻安全研究

为研究电子导向胶轮电车的安全性,通过分析电车运营条件和标准,确定电车需要满足侧翻安全性评估,完善了安全性研究。对某电子导向胶轮电车进行了有限元仿真计算,结果显示:该车体侧翻过程中结构未侵入生存空间,车体上部结构强度满足标准要求。

电子导向胶轮系统面临的问题及建议

电子导向胶轮系统作为一种低运量轨道交通系统,虽然目前发展形势尚不明朗,但中国城市轨道交通协会发布的团体标准《城市轨道交通分类》(T/CAMET 0001—2020)已将其纳入其中,国内部分轨道交通车辆制造企业已研发电子导向胶轮电车并在部分城市实现应用。结合电子导向胶轮系统应用情况,对电子导向胶轮系统发展过程中面临的问题进行分析,阐述电子导向胶轮系统在审批、标准、车辆许可、驾驶人资格等方面面临的问题,并提出助力电子导向胶轮系统快速发展的部分建议:简化电子导向胶轮系统等低运量轨道交通项目审批程序,参照电子导向胶轮系统相关团体标准进行电子导向胶轮系统建设和运营,将电子导向胶轮电车界定为城市轨道交通车辆,地方公安交通管理部门负责对电子导向胶轮电车车辆及驾驶人进行备案。

Output-feedback based partial integrated missile guidance and control law design

An output-feedback based partial integrated guidance and control (IGC) law for missile interceptor is proposed with the smooth finite time convergence property. Firstly, a novel outputfeedback based smooth sliding mode control is proposed for a class of nonlinear systems in the presence of immeasurable state and disturbance. The finite time convergence property of this control scheme is proved based on the Lyapunov stability and homogeneous principle. Then, the proposed control method is applied to the design of partial IGC law. A kind of scaling methods is also developed to reach the rapid convergence of the system. An important dominance of this control scheme is the smooth characteristic, which may result in chattering free convergence. The simulation results indicate the high precision and smooth elevator deflection of the proposed output feedback base partial IGC law. © 2016 Beijing Institute of Aerospace Information.

Influence of a Magnetic Guide Field on Self-Injection in Wakefield Acceleration

The influence of an external static field applied in the direction of propagation of a high intensity driving laser pulse on the electron trapping in laser wakefield acceleration is explored. It is shown that, in the case of self-injection, the electric charge accelerated can be enhanced in some physical situations.

Simulation of coherent spontaneous emission in a FEL with a groove guide

Based on a femtosecond linear accelerator, here we present a study of the use of a groove guide as the FEL interaction structure for high power FEL experiment. The transmission and attenuation characteristics of the dominant mode in the groove guide are discussed. And the coherent spontaneous emission in the FEL is simulated by Gover theory.

导学式电子实验报告的探索设计与实践

实验教学是培养化学专业学生实践能力、创新能力和解决问题能力的重要途径,针对西南大学化学化工学院实验教学中基础实验报告存在的问题,以有机制备实验——乙酸乙酯的制备为例,进行了化学实验报告相关的教学改革,以导学式的预习、实验记录和电子实验报告为指引,从课前、课中和课后三方面引导学生完成实验教学目标,提高了学生的创新技能和学习兴趣,把学生从大量的抄写实验报告时间中解脱出来,调动了学生学习的主动性和积极性,达到了预期的实验教学效果.

电子胃镜下斑马导丝转换技术用于空肠营养管置入术的安全性及有效性研究

目的探讨标准型胃镜下斑马导丝转换技术用于空肠营养管置入术的安全性及有效性。方法选取承德市中心医院2017年1月-2021年12月胃镜下放置螺旋型鼻肠管的患者80例,随机分为实验组与对照组,各40例。实验组使用标准型胃镜将斑马导丝置入十二指肠远端后,保持导丝位置相对固定,退出内镜,应用一次性导尿管将斑马导丝置换至鼻腔的方法代替经鼻胃镜下置入导丝技术;对照组使用标准型胃镜下钳夹推送置入螺旋型鼻肠管技术。结果实验组较对照组操作时间短,两组患者比较,差异有统计学意义(P<0.05);实验组鼻咽部不适及腹痛腹胀发生率明显低于对照组,两组患者比较,差异有统计学意义(P<0.05);两组患者一次性置管成功率、误吸及导丝移位发生率比较,差异均无统计学意义(P>0.05)。结论采用斑马导丝转换技术将斑马导丝置换至鼻腔的方法与传统内镜钳夹法相比,具有操作简单和并发症少等优势,且安全有效,可为广大基层医院提供技术支持,从而为消化内镜营养管置入术提供新思路。

低运量城市轨道交通系统发展思考

中国低运量城市轨道交通系统发展处于起步阶段,技术和产业成熟度不足,已运营线路客流效果普遍不理想,建设成本亦较高。结合国内外城市轨道交通系统发展现状,梳理低运量城市轨道交通系统的功能定位和分类。通过分析中国已运营和在建的低运量城市轨道交通线路的技术经济指标和客流效果,总结了系统制式选择的基本原则,包括运能轻量化、车辆轻型化、线下基础设施和系统设备轻量化、资产轻量化等方面。提出应综合论证低运量城市轨道交通系统在城市或城市组团和片区中的功能定位,并结合城市轨道交通系统网络建设和资源共享条件合理确定系统制式。最后,从系统发展的关键问题和建议两方面进行阐述,指出应结合国家相关政策要求和不断实践,推动低运量城市轨道交通系统的技术和产业逐步走向成熟。

多孔富缺陷半导体应用于光催化降解废水有机污染物

多孔半导体材料具有大的比表面积、反应物与产物的择优选择性、光子与电子的传输微通道,极利于促进光催化反应进程,提升催化效率,在废水有机物的吸附与光催化方面有着重要应用。多孔半导体独特的结构在废水有机物处理过程中可发挥出光化学、动力学及电子学上的优势:大孔结构可作为光扩散与传输路径增加光子的吸收率;介孔孔道对物质具备特定的选择性,对复杂反应体系显得尤为重要;微孔能为电荷传导与迁移提供微观通路。结构缺陷以往被认为是光催化反应中的不利因素,会成为电子-空穴对的复合中心,缩短光生载流子的寿命,降低反应效率。近来研究者提出了新观点:结构缺陷能为光催化过程提供更多的反应场所和活性位点,表面缺陷的储氧作用可促进光催化氧化反应进程,晶格缺陷可作为光生电子迁移的微观通道。将缺陷位引入多孔构架设计成多孔缺陷结构,缺陷位的引入可显著增强多孔结构的光电及催化性能,在废水有机物光催化反应中突显出储氧作用、载流子分离与传输效应及优良的的催化性能。半导体多孔结构协同缺陷活性位极大地促进了光催化反应进程,提升了废水有机物光催化氧化分解效率,缺陷活性位与多孔结构相结合将是光催化剂设计的一个新方向。本文概述了多孔半导体材料在光催化反应中的结构优势、多孔半导体微纳结构的“导向合成”与缺陷位设计、多孔缺陷半导体在光降解废水有机物过程中的光电效应及作用机制,并提出结构缺陷作为光生载流子复合中心的负面效应是应用研究中需要克服的问题,分析及展望了多孔缺陷结构光催化剂的应用前景,为制备高效降解废水有机物的高活性光催化材料提供设计思路。