空间高能电子探测器准直仪的设计研究

空间电子探测器的准直仪的目的是限制仪器的探测张角和几何因子,而电子与准直仪材料的散射效应严重,准直仪的设计优劣将直接影响仪器的测量精度。本文以我国的风云四号卫星的高能电子探测器为例,在基础准直仪的结构基础上进行了改进设计,分析了在准直仪内的加齿结构、齿形、齿厚、齿深、齿数等参数对准直仪反散射能力的影响。分析发现齿形对反散射能力的影响最大,齿深对反散射能力影响较小。提出了最优准直仪结构,有效改善了准直仪内电子散射问题,总结了空间电子探测器的准直仪设计的经验和原则,为以后准直仪的优化提供参考。     

电子测压器动态校准系统的研究

电子测压器是新型火炮膛压测试仪器,本文介绍了该仪器动态校准系统的原理、影响其精度的因素,并讨论了处理数据的方法.     

电子测压器动态校准系统的研究

电子测压器是新型火炮膛压测试仪器,本文介绍了该仪器动态校准系统的原理、影响其精度的因素,并讨论了处理数据的方法.     

浅谈实验室仪器的期间核查

以“准确、公正、科学”为宗旨的实验室 ,为保证其检验结果的准确性、精确性和可靠性 ,增强市场竞争力 ,维护顾客和社会的权益 ,除检测方法科学、人员素质和环境条件满足要求外 ,仪器的有效性、可靠性是至关重要的决定性因素。实验室不仅应配备精度达到技术规范或标准要求的仪器 ,而且必须持续保证仪器处于完好状态 ,才能给出可信的数据 ,保证检验结果的有效性和可靠性。但是由于仪器自身的机械、光学和电子等特性决定了仪器的易损坏、不稳定、易漂移性等现象的出现 ,这就无法保证仪器提供的检验数据持续准确、可靠 ,因此对仪器的期间核查就…     

TCM5电子罗盘在三维流速计中的应用

随着电子技术的进步,基于磁通门测量原理的小型三维电子罗盘广泛的应用于海洋仪器、水下机器人、小型飞行器等仪器和设备的导航和定向系统中,和陀螺仪相比,具有体积小、功耗低、零漂小的特点。通过在三维海流计中应用PNI公司的TCM5型电子罗盘实现流速的三维矢量测量。通过实验验证和分析,证明该电子罗盘的具有较高测量精度,抗硬磁场干扰能力强的特性。     

配料电子皮带称传动系统的改造

本文主要阐述了目前电子皮带秤自动配料系统在多煤种配煤中存在影响配料精度的有关问题，通过对本厂备煤车间电子配料秤使用现状的分析，提出了影响配煤精度、配煤成本等有关问题，着重对电子皮带秤传动系统的改造进行了详尽的阐述，并为提高焦炭等产品质量作出了贡献，为公司节约了生产成本，降低了精煤损耗，稳定了工艺系统。     

高频真空熔融气相色谱分析仪

本文对高频真空熔融气相色谱分析仪的测试原理、方法、结构、特点等方面进行了 介绍和分析。并用该仪器测定了钢中氧，结果表明，该仪器的精度是比较高的。     

数字式电子水平角度仪

由重庆华川机械厂研制的数字式电子水平角度仪能在一台仪器上同时进行水平和角度测量，并可通过电子显示器直观读数，可以方便、快捷地测出一个平面与水平之间0至90度的夹角，其水平测量精度高于传统的气泡式水平器5～10倍。     

光电跟踪测量仪器的系统误差的修正方法

对于现代光电跟踪测量仪器来说，为获得较高的实际使用精度，必须对仪器的系统误差进行检测并加以修正。本文是根据从事精度检测工作的实际经验，着重讨论在外场对静态系统误差进行检测和修正的方法，并且指出了采用系统误差修正的方法对于仪器设计和仪器使用的指导意义。     

具有自动保护功能的交流开关型稳定电子流发射器

本文简介了“交流开关型稳定电子流发射器”，在超高真空电离计中可普遍应用，其对各种规格的真空规管的热阴极都有相当强的适应能力。 本仪器是一种新型的电子稳发射电路，与以往仪器相比，供电效率可成倍提高，且大大缩小了仪器的体积、重量和功耗，提高了热稳定性。并附有优良的阴极保护系统和逻辑信号输出电路，以利于与电算机相配。发射电流具有宽阔的动态范围，从１０μＡ到１００ｍＡ之间可任意调节。长期运行中稳定度优于０．１％。 仪器只要稍作改动，就可扩展应用到质谱计、表面仪器等工作于真空环境下的电子源设备中。     

Novel ferroelectric materials for phased array antennas

Various composites of barium strontium titanium oxide (BSTO) combined with other nonelectrically active oxide ceramics have been formulated for application in phased array antennas. In general, the composites have adjustable electronic properties which can be tailored for use in phased array antennas and other phase shifting devices. The dielectric constant and the loss tangents have been reduced to enhance the overall impedance matching and thereby lowering the insertion loss of the device. In addition, the overall tunability, the change in the dielectric constant with applied voltage, is maintained at a sufficiently high level. In order to address a broad frequency range in the microwave region, the composites have been fabricated in bulk ceramic, thick film, and thin film form. This article discusses the processing, material characterization, and electronic properties of the composites in MHz and GHz frequencies     

Breakthrough advances in low loss, tunable dielectric materials

 Low loss, tunable dielectric materials are important for phased array antenna and other device applications. Various composites of barium strontium titanium oxide (BSTO) combined with other nonelectrically active oxide ceramics have been formulated for such uses. The dielectric constant and the loss tangents of these composites have been reduced to enhance the overall impedance matching and thereby lowering the overall insertion loss of the device. The material has been fabricated in bulk ceramic, thick film, and thin film form to address a broad range of frequency applications. The material fabrication methods and the electronic properties of these composites will be discussed in this article. Received: 21 July 1998 / Reviewed and accepted: 22 October 1998     

A Multifunctional Electronic Skin Empowered with Damage Mapping and Autonomic Acceleration of Self-Healing in Designated Locations

Integrating self-healing capabilities into soft electronic devices and sensors is important for increasing their reliability, longevity, and sustainability. Although some advances in self-healing soft electronics have been made, many challenges have been hindering their integration in digital electronics and their use in real-world conditions. Herein, an electronic skin (e-skin) with high sensing performance toward temperature, pressure, and pH levels—both at ambient and/or in underwater conditions is reported. The e-skin is empowered with a novel self-repair capability that consists of an intrinsic mechanism for efficient self-healing of small-scale damages as well as an extrinsic mechanism for damage mapping and on-demand self-healing of big-scale damages in designated locations. The overall design is based on a multilayered structure that integrates a neuron-like nanostructured network for self-monitoring and damage detection and an array of electrical heaters for selective self-repair. This system has significantly enhanced self-healing capabilities; for example, it can decrease the healing time of microscratches from 24 h to 30 s. The electronic platform lays down the foundation for the development of a new subcategory of self-healing devices in which electronic circuit design is used for self-monitoring, healing, and restoring proper device function.     

Evidence of electronic growth in titanium- and cobalt-silicide islands

A possibility of growing highly mismatched and yet two-dimensional heteroepitaxial deposits, is both fascinating in terms of basic science and technologically important. So far, stabilization of flat morphology by a reduction of the overall electron energy in a quantum well (hence termed “electronic growth”), has been observed exclusively in heteroepitaxy of simple metals, lead, and silver. This work shows, that a broader class of functional materials can be grown “electronically,” such as titanium- and cobalt-silicide nano-islands on Si(111), despite their more complex electronic structure.     

Electronic Metal–Support Interaction of Single-Atom Catalysts and Applications in Electrocatalysis

The electronic metal–support interaction (EMSI), which acts as a bridge between theoretical electronic study and the design of heterogenous catalysts, has attracted much attention. Utilizing the interaction between the metal and the support is one of the most essential strategies to enhance electrocatalytic efficiency due to structural and synergetic promotion. To date, as the ideal model for realizing EMSI, many types of single-atom catalysts (SACs) have been developed. The understanding of the electronic interaction on SACs has also been pushed to a higher level. However, systematic theories and operando experiments are seldom reported, and will be necessary to put forward and be carried out, respectively. Herein, the types, characterization, mechanism, and electrocatalytic applications of EMSI are comprehensively summarized and discussed. In addition to the basic information above, the challenges, opportunities, and future development of the EMSI on SACs are also proposed to present an overall view and reference to the later research.     

Engineering Transport in Manganites by Tuning Local Nonstoichiometry in Grain Boundaries

Interface‐dominated materials such as nanocrystalline thin films have emerged as an enthralling class of materials able to engineer functional properties of transition metal oxides widely used in energy and information technologies. In particular, it has been proven that strain‐induced defects in grain boundaries of manganites deeply impact their functional properties by boosting their oxygen mass transport while abating their electronic and magnetic order. In this work, the origin of these dramatic changes is correlated for the first time with strong modifications of the anionic and cationic composition in the vicinity of strained grain boundary regions. We are also able to alter the grain boundary composition by tuning the overall cationic content in the films, which represents a new and powerful tool, beyond the classical space charge layer effect, for engineering electronic and mass transport properties of metal oxide thin films useful for a collection of relevant solid‐state devices.     

First principles results of structural and electronic properties of ZnS clusters

We present results of the study of Zn _n S _n (1 ≤?n?≤ 9) clusters, using the density functional formalism and projector augmented wave method within the generalized gradient approximation. Along with the structural and electronic properties, nature of bonding and overall stability of clusters has been studied.     

桥梁电子化人工巡检养护管理系统

将危险性分析与量化管理理念应用于桥梁电子化人工巡检养护管理系统的总体设计中,为大型桥梁量身定制巡检养护规划,规范桥梁巡检养护流程,编制巡检养护手册,用于指导巡检养护工作的实施;针对桥梁结构的具体特点,建立专门结构的损伤库,编制电子化人工巡检养护软件,实现巡检养护管理工作的电子化。     

The accuracy evaluation of NIST-7

We have performed evaluations of the major systematic errors in NIST-7 with an overall uncertainty of less than a part in 10¹⁴. The complete evaluation process has been separated into two parts. With a computer-controlled, digital servo system and some new measurement techniques, we now perform core evaluations (second-order Zeeman and Doppler shifts, cavity pulling and phase shift, line overlap and some electronic shifts) with an overall uncertainty of less than one part in 10¹⁴ in just a few days of measurements. The complete evaluation of all small and subtle effects in both the physics and electronics requires a few hundred days of data. But, these small effects are not variable at the 10^-14 level and their infrequent evaluation does not detract from the operational accuracy of the standard     

Integration of a three-stage expander into a CO2 refrigeration system

The inclusion of an expander with work recovery provides two advantages for transcritical CO₂ refrigeration cycles: the COP is improved and the exhaust pressure of the main compressor is lowered. Several designs of expanders have been proposed for this application and some prototypes have been tested already. In our laboratory a three-stage expander has been developed, which replaces the throttle valve of the normal refrigeration cycle and expands into the two-phase region. For optimum integration into the overall system it is proposed to install a vapour-liquid separator between the second and third stage of expansion. The vapour is guided back to the third expander stage whereas the liquid is supplied to the cooling stations via thermostatic or electronic expansion valves.