基于多目标属性决策和信息熵值法的港口集装箱装卸设备选型评价

装卸设备选型对专业集装箱码头的发展具有重大意义,本文从这一现实问题入手,基于集装箱装卸设备选型的多属性特征以及港口物流工业的一体化趋势,提出了基于信息熵值法的多目标属性决策模型(Multi-attribute decision-making Model Based on Information Entropy Method, MADM-IEM)。以装卸设备为研究对象,构建全面的装卸设备选型评价指标体系;针对指标属性不相容性和不确定性、相关指标难以量化呈现的特点,运用多属性决策和信息熵值法的数据效用值相结合的方法,客观、合理地计算属性指标的权重系数,并进行归一化处理;在此基础上结合ELECTRE法和TOPSIS法,对装卸设备进行综合排序,由此确定设备选型结果。注意到,两种方法求解结果具有一致性,验证了该模型的可行性和有效性。最后对港口装卸设备选型评价进行灵敏度分析,深入讨论评价指标的权重变动对结果的影响。研究结果充分表明提出的MADM-IEM模型能为中小型内河港口码头的基础建设规划提供科学合理的决策依据。     

基于MEMS技术的多媒体空中鼠标

本文采用MEMS加速度传感技术,触控技术以及无线射频的多功能鼠标的电路设计方案,首先系统通过三轴陀螺仪和三轴加速度计的数据进行实时采集,将采集到的数据传送给STM32微控制器,用于计算鼠标的位移、角度、角速度等参数,并利用无线模块将数据发送到接收端,再通过USB协议发送到电脑端。针对现有空中无线鼠标通信距离、电池供电等问题的限制,本文采用通信距离更长的2.4GHZ无线电波,可循环充电利用的锂电池替代传统电池供电,并且利用USB设备通信,在接收端将大容量存储设备与鼠标设备整合复用,可实现二者之间的任意切换,提高了该鼠标系统适应实际应用环境的能力。     

基于综合监控的设备状态修方案研究

随着工业控制领域的不断发展,综合监控系统已经日趋成熟并于工业现场运行较长时间。而基于综合监控系统获取的大量历史数据的分析和实时数据的使用并没有开展深入的探讨。本方案提出了一种基于综合监控系统的状态修方案,把综合监控系统的历史数据经过一定的清洗,建模导入到大数据平台,通过相应的算法分析,从而改善维修决策模型并建立设备评价体系;把实时数据实时的传递到设备状态页面,减轻了传统巡检工作,保证了设备检查效果;把设备报警数据通过分类,分项,直接派生检修工单,实现了设备维修的自动化。     

基于EPICS的慢速设备异步控制应用研究

针对直线感应加速器控制系统大多数前端设备为带通讯接口的慢速设备的实际情况,采用异步通讯模块Asyn和基于字节的模块StreamDevice相结合的方法实现该类设备在实验物理与工业控制系统（EPICS）架构下的分布式控制。系统中使用的国产或自行研制的设备的命令格式不是SCPI格式,而控制系统常需要在一个I/O命令中写入多个参数（PV）,而StreamDevice协议中,多个PV设置无法在一个协议函数中实现。采用EPICS实时数据库的Calcout记录作为多参数输入容器,将多个PV组成一个结构化数组,从而实现多个PV变量的同时设置。同样,针对多参数同时读取的情形,使用waveform记录在一次读入操作中能获取多个PV变量的值。     

大学物理实验教学应突出原理性

大学物理实验是理工科大学教学当中最基本、最重要的教学环节,为了巩固基本理论知识,促进理论教学,培养理论联系实际的能力而开设的。在大学物理实验教学中,不是简单的技能培训。因而实验教学要将实验原理和实验操作并重,实验设计应以原理透明化,突出加强。在真正懂得原理的前提下才能达到锻炼操作能力和理解理论知识的目的,并为创新型人才培养真正起到奠定基础的作用。     

Magnetic properties of bulk polycrystalline Pr1-x Ndx（x=0,0.8）FeB permanent magnets

For spin reorientation （SRT）, the applications of sintering NdFeB permanent magnets are limited at low temperature. The sintering PrFeB permanent magnet （PM） presents no SRT and shows excellent magnetic properties at low temperature. The magnetic properties of bulk polycrystalline sintering Prl-xNdxFeB （x = 0 and 0.8 correspond to P42H and N50M respectively） are studied in this paper. The results show that magnetic properties and stability of N50M are better than those of 42H at room temperature. With the decrease of temperature, the parameters ofBr, Hcb, and Hci of P42H present a nearly linear increasing trend; Br and Hcb of N50M first increase and then decline, Hci presents an increasing trend. At 77 K, Br, Hci, and Jr of P42H are increased by 18.7%, 308%, and 17.1% respectively over than those at 300 K; at 120 K, Br, Hci, and Jr of N50M are increased by about 16.19%, 245%, and 12.6% respectively over than those at 300 K. The magnetic properties of P42H are better than those of N50M at low temperature. The sintering PrFeB is the preferred PM in various low-temperature devices.     

Strong and broadband terahertz absorber using Si02-based metamaterial structure

We design and experimentally demonstrate a broadband metamaterial absorber in the terahertz （THz） band based on a periodic array of aluminum （A1） squares with two different sizes. A thin silicon dioxide （SiO2） film rather than a conventional polyimide （PI） layer is used as a dielectric spacer to separate A1 squares from the platinum （Pt） ground plane in our design, which significantly improves the design precision and the feasibility of the device fabrication. The combination of different sizes of AI squares gives rise to an absorption bandwidth of over 210 GHz with an absorption of over 90%. Our results also show that our device is almost polarization-insensitive. It works very well for all azimuthal angles with an absorption of beyond 80%.     

New terahertz dispersive device for single-shot spectral measurements of terahertz pulse

A new terahertz dispersive device designed for single-shot spectral measurements of broadband terahertz pulses is proposed. With two-dimensional quasi-randomly distributed element design, the device exhibits approximately the dispersive property of single-order diffraction in far field. Its far-field diffraction pattern is experimentally verified employing a continuous terahertz source centered at 2.52 THz and a pyroelectric focal-plane-array camera, which is in good agreement with the numerical result. The device provides a new approach for direct single-shot spectral measurements of broadband terahertz waves.     

Beam dynamics studies of the photo-injector in low-charge operation mode for the ERL test facility at IHEP

The energy recovery linac test facility （ERL-TF）, which is a compact ERL-FEL （free electron laser） two-purpose machine, was proposed at the Institute of High Energy Physics, Beijing. As one important component of the ERL-TF, the photo-injector that started with a photocathode direct-current gun has been designed. In this paper, optimization of the injector beam dynamics in low-charge operation mode is performed with iterative scans using Impact-T. In addition, the dependencies between the optimized beam quality and the initial offset at cathode and element parameters are, investigated. The tolerance of alignment and rotation errors is also analyzed.     

High-Power Nd：GdVO4 Innoslab Continuous-Wave Laser under Direct 880 nm Pumping

A high-power cw end-pumped laser device is demonstrated with a slab crystal of Nd：GdVO4 operating at 1063nm. Diode laser stacks at 880nm are used to pump Nd：GdVO4 into emitting level 4^F3/2. The 149 W output power is presented when the absorbed pump power is 390 W and the optical-to-optieal conversion efficiency is 38.2%. When the output power is 120 W, the M^2 factors are 2.3 in both directions. Additionally, mode overlap inside the resonator is analyzed to explain the beam quality deterioration.