电磁屏蔽效能的测量

电磁屏蔽涂料的广泛应用要求有一种能快速有效确定屏蔽效能的测量方法.在介绍法兰同轴测试装置的基础上.提出了一种按远场同轴传输线测量平面材料的方法,用来测量屏蔽涂料的屏蔽效能.具体分析了测试系统的主要设备及其技术参数,同时给出了样本测试结果.结果表明,该测量方法能有效测试屏蔽涂料及类似平面屏蔽材料的屏蔽效能.     

一种高屏蔽效能嵌入式计算机设计

针对嵌入式计算机存在的空间辐射超标,电磁泄漏问题,设计实现一种具有高屏蔽效能的计算机。计算机机壳的设计,以电磁屏蔽的材料屏蔽效能、缝隙处理方法为基础,采用了工程化的方法,保证设计的计算机可靠、合理。通过验证,铝合金材料的机壳屏蔽效能较高,同时,依据试验结果改进了计算机孔洞、缝隙的设计。试验在GJB标准下进行EMC空间辐射试验（RE102）项目,检验计算机对电磁波的屏蔽能力。最终计算机通过了RE102试验,其在空间辐射水平上不超过环境噪声3dB,表明计算机机壳具有较高的屏蔽效能。     

孔缝对电力设备机箱电磁屏蔽效能的影响

电力设备电磁屏蔽效能的好坏直接影响着电力系统的电磁兼容性能,而其机箱上的孔缝造成的电磁泄露是一个不容忽视的问题,如何对它们产生的影响进行科学评价是很有必要的。文章分析了孔缝的形状、大小和数量对电力设备电磁屏蔽效能的影响,并提出了具体的金属屏蔽机箱的设计建议。     

电磁屏蔽在电子设备结构设计中的应用

随着信息化的高速发展,电子设备数量与日俱增,使用的密集程度越来越大,电磁干扰也越来越突出。为确保这些设备在工作时不会受到外界电磁场的干扰,同时不对该环境中其他设备造成不允许的电磁干扰,必须对电子设备进行电磁屏蔽。阐述了电子设备屏蔽设计要求、屏蔽效能的影响因素、电子设备应采取的屏蔽措施,并通过屏蔽设计改进实例说明电磁屏蔽技术在电子设备结构设计中的重要作用。     

矿用产品金属外壳的电磁屏蔽效能分析

对采用单层不锈钢外壳的矿用产品的电磁屏蔽效能进行了分析与计算,得出产品金属外壳的电磁屏蔽效能与采用的金属材质、厚度以及因加工工艺形成的隙缝、开孔有关,为提高矿用产品的电磁屏蔽性能提供了工程经验。     

电磁屏蔽室的设计与施工

分析了电磁屏蔽室建设标准和屏蔽效能,重点讨论了电磁屏蔽室的技术方案,明确了施工程序,并提出了其质量保证措施,可为电磁屏蔽室设计或施工提供参考,有一定的指导和借鉴意义.     

电磁屏蔽技术的分析研究

在现实生活中由于干扰普遍存在,人们为避免干扰而想尽了各种屏蔽方法,但效果并不理想。电磁屏蔽是解决电磁兼容问题的重要手段之一,大部分电磁兼容问题都可以通过电磁屏蔽来解决。用电磁屏蔽的方法来解决电磁干扰问题的最大好处是不会影响电路的正常工作,因此不需对电路做任何修改。本文在分析各种干扰源性质的基础上,分别对电场屏蔽和磁场屏蔽进行了详细的介绍,以实现最佳的抗干扰效果。     

电磁屏蔽技术的分析研究

在现实生活中由于干扰普遍存在,人们为避免干扰而想尽了各种屏蔽方法,但效果并不理想.电磁屏蔽是解决电磁兼容问题的重要手段之一,大部分电磁兼容问题都可以通过电磁屏蔽来解决.用电磁屏蔽的方法来解决电磁干扰问题的最大好处是不会影响电路的正常工作,因此不需对电路做任何修改.本文在分析各种干扰源性质的基础上,分别对电场屏蔽和磁场屏蔽进行了详细的介绍,以实现最佳的抗干扰效果.     

夹网屏蔽玻璃屏蔽效能仿真计算简化模型研究

为了减少夹网屏蔽玻璃在电磁场数值计算中剖分的网格数量,基于时域有限差分周期结构谱算法(Spectral Finite-Difference Time-Domain,SFDTD)仿真了单层夹网屏蔽玻璃的屏蔽效能,基于Schelkunoff屏蔽理论提取出金属网的等效电导率,应用CST电磁仿真软件建立了一种屏蔽玻璃仿真简化模型,解决了细微结构屏蔽材料难以仿真计算的难题。仿真结果表明,等效电导率方法具有很高的计算精度,为计算具有细微结构屏蔽材料的机箱、方舱等结构的屏蔽效能提供了有效途径。     

一种高性能FPGA辐射发射抑制方法研究

随着半导体技术的不断发展,集成电路的电路速度、集成密度和I/O端口数量已大大增加,FPGA的小型化、高密度集成会引发电磁兼容性的问题,电磁屏蔽是抑制电磁辐射最有效的方法,选择高效的电磁屏蔽材料可以取得良好的屏蔽效果。而目前电磁屏蔽材料在FPGA上的应用较少,因此选取了一款具有代表性的高性能FPGA作为研究对象,通过近场扫描测试来研究不同状态下FPGA的电磁辐射发射问题;针对芯片的特点,选取了复合金属屏蔽罩和吸波导电海绵作为电磁屏蔽材料,对FPGA的辐射发射进行抑制。进一步的实验结果表明,由金属材料复合而成的屏蔽罩具有更好的屏蔽效能,达到了10 dBm,相比之下,吸波导电海绵的压缩性和结构稳定性更有助于FPGA在多场景下应用。     

Full-Surround Image Display Technologies

This paper presents two methods for developing full-surround displays: rear-projection-based Garnet Vision and specialized spherical screen named Ensphered Vision. The Garnet Vision is a closed polyhedron screen. A viewer stands inside the polyhedron so that image covers full solid angle around the viewer. Optimum configuration of polyhedron is determined by two criteria: pixel efficiency and space efficiency. The criteria maximizes space utility of the display. Through examination of these criteria, rhombic dodecahedron is chosen. A dodecahedron screen with twelve projectors is built, in which a viewer can stand. Ensphered Vision is an image display system for full-surround spherical screen. Sphere is an ideal shape of a screen that covers human visual field. Distance between eyes and screen should be constant while a viewer rotates the head. We use single projector and a convex mirror in order to display seamless image. The optical system employs two mirrors: a plain mirror and a spherical convex mirror. The spherical convex mirror scatters the light from the projector in the spherical screen. The flat mirror provides the viewer to the sweet-spot where he/she can see the image from the center of the sphere. This optical configuration enables seamless wide-angle image in a very limited space.     

Monte Carlo calculation of CRT screen efficiency

Abstract— The influence of phosphor grain size on overall CRT screen efficiency has been studied by Monte Carlo calculation of the energy absorption and the photon propagation in the phosphor screen. To calculate the energy absorption, the phosphor layer is modeled as a randomly packed layer of spheres with defined size distribution and screen weight. The absorbed energy in the phosphor grains is obtained from cross sections of the physical processes involved. The optical efficiency is calculated taking into account the scattering and absorption probability of the photons within the phosphor screen. The optimal screen efficiency which can be obtained for CRT screens with constant phosphor powder efficacy and aluminum reflectivity increases with increasing median grain size of the phosphor powder. Depending on the actual anode voltage applied, the CRT screen efficiency increases for a 32‐kV anode voltage by 15%, going from 3‐ to 8‐μm median grain size of the phosphor powder. Larger grains at this anode voltage do not further increase the efficiency. Grain‐size distribution has no noticeable influence on screen efficiency.     

基于FPGA控制的LED点阵屏产品标识和测试

根据led点阵显示屏的特点，本文提出了一种产品标识和测试方法，它简化了产品的测试手段，方便快捷，提高了工作效率。     

基于Linux液晶显示触摸屏控制的新设计与实现

在分析电阻触摸屏和ADC的工作原理的基础上,采用微处理器LM3S4749自带模块ADC和GPIO代替触摸屏专用控制器ADS7846.设计出LM3S3749与液晶显示触摸屏接口电路的硬件连接,并给出必要的序流程图和函数代码.提出触摸屏触点坐标的获得方法与液晶屏显示同步的算法,以提高设计触摸屏与液晶的效率,满足控制精度.     

晶体硅太阳电池用电极设计的研究

随着诸如新型用气体完成而不是化学药品的制绒方法等新技术的改进和适用于更细的细栅宽度的导电浆料的替代,多晶电池的效率变得越来越高。多晶电池的常规工艺顺序有酸化学试剂制备的绒面,磷扩散,边缘绝缘,减反射膜的沉积,背面银/铝浆、铝浆的印刷及正面银浆的印刷。本文通过几组实验数据来讨论不同的丝网设计与浆料特性的匹配数据,从而得出最优的印刷质量和电池效率。     

Where to put the creases? Interactions between hand length,task, screen size,and folding method on the suitability of hand-held foldable display devices

Limited information is available regarding ergonomic foldable display device forms. This two-stage study involving young South Koreans (divided into three hand-length groups) was conducted to determine ergonomic forms for hand-held foldable display devices considering folding/unfolding comfort and preference. Stage I obtained the suitability of three screen sizes for five tasks. Stage II evaluated 14 different bi- and tri-folding methods considering screen size, folding direction, and folding time. The effects of hand length were all non-significant. Screen size preferences were task-dependent; small screens were preferred for making calls, and medium screens for web searching and gaming. Folding methods affected folding/unfolding comfort and preference; outward screen and Z-shape screen folding were the most preferred bi- and tri-fold concepts, respectively. Screen protection and access appeared to be competing factors in the user preference determination process. Foldable screen size and folding method should be determined by considering tasks, folding/unfolding comfort, and user preferences.

Practitioner summary: A 13.5?cm screen was preferred for making calls, whereas a 17.5?cm screen was best for web searching and gaming. An outward bi-fold screen concept with a 17.5?cm screen and Z-shape tri-fold screen concept with a 22.9?cm screen were preferred. Overall, the Z-shape concept was most preferred.

Abbreviations: SD: standard deviation; ANOVA: analysis of variance; H: Height; W: Width; T: Thickness     

High luminance YAG single crystal phosphor screen

Epitaxial phosphors of Ce,Tb:YAG containing Lu³⁺ and Ga³⁺ on YAG (yttrium aluminum garnet) single crystal faceplates have properties which are suitable for projection CRTs. The external efficiency of the single-crystal YAG screen is relatively low. Truncated cone geometry can increase the external efficiency by a factor of 5.2, if such a shape can be formed in the phosphor layer. An anisotropy etching process of YAG has been developed for the fabrication of a YAG luminescent screen with truncated square mesas. A large fraction of the cathodoluminescent can be directed through the untextured front surface of the crystal. An improvement in phosphor efficiency by a factor of 2.3 has been achieved.     

基于西门子PLC和变频器的桥式起重机控制系统

针对目前桥式起重机存在的可靠性差、操作复杂、故障率高、电能浪费大、效率低等缺点,结合某冶金企业桥式起重系统改造实例,设计一套以PLC为控制中心、应用触摸屏及变频器的起重自动控制系统.     

丝网印刷技术在平板式汽车氧传感器制作中的应用

平板式汽车氧传感器在节能环保中担任着重要的角色。将丝网EBSU技术应用到平板式汽车氧传感器的制作中已经得到认可。本文将结合本课题组的研究对制作平板式汽车氧传感器时丝网印刷的各种参数做简单介绍。     

Two-mode target selection: Considering target layouts in small touch screen devices

A variety of studies have been conducted to improve methods of selecting a tiny virtual target on small touch screen interfaces of handheld devices such as mobile phones and PDAs. These studies, however, focused on a specific selection method, and did not consider various layouts resulting from different target sizes and densities on the screen. This study proposes a Two-Mode Target Selection (TMTS) method that automatically detects the target layout and changes to an appropriate mode using the concept of an activation area. The usability of TMTS was compared experimentally to those of other methods. TMTS changed to the appropriate mode successfully for a given target layout and showed the shortest task completion time and the fewest touch inputs. TMTS was also rated by the users as the easiest to use and the most preferred. TMTS could significantly increase the ease, accuracy, and efficiency of target selection, and thus enhance user satisfaction when the users select targets on small touch screen devices.

Relevance to Industry

The results of this study can be used to develop fast and accurate target selection methods in handheld devices with touch screen interfaces especially when the users use their thumb to activate the desired target.