Design of a Compact Monopole Antenna for UWB Applications

In this paper, a low cost, highly efficient and low profile monopole antenna for ultra-wideband (UWB) applications is presented. A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency. To design the proposed structure, three steps are utilized to achieve an UWB response. The bandwidth of the proposed antenna is improved with changing meander lines parameters, miniaturization of the ground width and optimization of the feeding line. The measured and simulated frequency band ranges from 3.2 to 12 GHz, while the radiation patterns are measured at 4, 5.3, 6 and 8 GHz frequency bands. The overall volume of the proposed antenna is 26 × 25 × 1.6 mm3 ; whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025, correspondingly. The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98% for the entire wideband. Design modelling of proposed antenna is performed in ANSYS HFSS 13 software. A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.     

光纤光栅传感技术及其在石油工业中的应用

阐述了光纤光栅温度和应变传感的响应机理．对光纤光栅多参量区分测量技术和光纤光栅传感网络复用与解调技术进行了综合评述．结合光纤光栅传感技术的本质突出优势和石油工业特点,讨论了其在油气生产中温度和压力测量、测井技术、地震波检测、长距离石油管道监测等方面的应用．     

Development of a Multiband near-to-far Infrared Radiance COmparator (MIRCO)

In recent years, there has been a growing demand to calibrate industrial blackbodies both at short wavelengths for lower temperatures and at long wavelengths for higher temperatures. User requests cover a very wide temperature range, from  −20°C to 1,500°C in the infrared bands used by thermal cameras or as defined by specific applications (especially the 1–3 μm, 3–5 μm, and 8–12 μm bands). Therefore, LNE (Laboratoire National de Métrologie et d’Essais) has developed a radiance comparator with a mirror-based optical system, an associated set of interference filter wheels, a modular holder for several infrared detectors, and a lock-in amplifier. This setup is designed to be very versatile in terms of wavelength and temperature. Targeted performances have a thermal resolution better than 0.05°C, and a known and controlled size-of-source effect (SSE). A silicon detector and a visible-to-near infrared integrating sphere were used to assess the stray light inside the housing, and supplementary baffles and stops were used to reduce it to an acceptable level. The investigation included measurement of the SSE for this comparator layout. Then, the performance in the 3–5 μm and 8–12 μm bands, using, respectively, indium antimonide (InSb) and mercury cadmium telluride (MCT) detectors, was evaluated using a water heat-pipe blackbody. This paper describes the modeling and the technical solutions implemented to optimize the optical system. Preliminary results are presented for the short-term stability, the thermal resolution between  −20°C and 960°C, and also the SSE up to 60 mm in these bands.     

地质聚合物的研究与应用发展前景

地质聚合物是一种新型高性能胶凝材料.由于其特殊的缩聚三维网络结构,使其在众多方面具有高分子材料、水泥和陶瓷等材料的特征.综述了国内外地质聚合物的制备研究及聚合反应机理,概述了地质聚合物具备的性能特点及其在土木工程、快速修补和有毒废料及放射性废料处理等领域广阔的应用发展前景,分析了目前国内地质聚合物推广应用中存在的问题,并结合自身的研究提出了几点建议.     

Development of a Tunable LED-Based Colorimetric Source

A novel, spectrally tunable light-source utilizing light emitting diodes (LEDs) for radiometric, photometric, and colorimetric applications is described. The tunable source can simulate standard sources and can be used as a transfer source to propagate photometric and colorimetric scales from calibrated reference instruments to test artifacts with minimal increase in uncertainty. In this prototype source, 40 LEDs with 10 different spectral distributions were mounted onto an integrating sphere. A voltage-to-current control circuit was designed and implemented, enabling independent control of the current sent to each set of four LEDs. The LEDs have been characterized for stability and dependence on drive current. The prototype source demonstrates the feasibility of development of a spectrally tunable LED source using LEDs with up to 40 different spectral distributions. Simulations demonstrate that such a source would be able to approximate standard light-source distributions over the visible spectral range—from 380 nm to 780 nm—with deviations on the order of 2 %. The tunable LED source can also simulate spectral distributions of special sources such as discharge lamps and display monitors. With this tunable source, a test instrument can be rapidly calibrated against a variety of different source distributions tailored to the anticipated uses of the artifact. Target uncertainties for the calibration of test artifacts are less than 2 % in luminance and 0.002 in chromaticity for any source distribution.     

原子层沉积技术及应用发展概况

首先回顾了原子层沉积(ALD)发展历史,介绍了ALD的基本工艺和ALD薄膜具有的优良特性,并与传统的薄膜制备工艺进行了对比研究.重点阐述了ALD在微电子技术、微电子机械系统以及光学工程中的几个应用研究现状.分析了ALD目前存在的问题,并对ALD未来的发展进行了展望.     

Laser Sensing of a Subsurface Oceanic Layer. II. Polarization Characteristics of Signals

In Part I of this paper we calculated depth profiles and polarization characteristics of airborne lidar return signals by the Monte Carlo method. Here we calculate the polarization characteristics of lidar return signals for different types of water. We demonstrate the feasibility of polarization lidar application to the detection of underwater inhomogeneities of different origins. It is shown that simultaneous analysis of depth profiles of the lidar return signal power and signal depolarization ratio substantially increases the information content of airborne lidar sensing of seawater. We compare calculated results with the data of airborne lidar measurements for lambda = 0.53 mum.     

冷喷涂技术的发展与工业应用

冷喷涂技术是近二十年内产生并得到蓬勃发展的一种材料改性新技术.冷喷涂由于全过程温度低于喷涂颗粒的熔点,因而可以大大减小或消除传统热喷涂工艺中遇到的如高温氧化、熔化、残余热应力等问题.本文介绍了国内外冷喷涂技术的产生、研究发展以及在改进航空发动机压气机内部流动等方面的应用研究状况,展示了冷喷涂技术的巨大发展潜力与广阔工业应用前景.     

基于Matlab平台的组合结构动态分析工具箱的开发与应用

组合结构动态分析是结构动力学的一个重要分支。本文开发了一个基于Matlab平台的面向对象的组合结构动态分析工具箱，概括了工具箱所采用算法的理论背景，介绍了工具箱的构成和流程，给出了工具箱开发过程中一些关键问题的解决方案，并以一个两层二维框架结构的组合结构动态特性分析为例来验证工具箱的可靠性。组合结构分析结果与有限元理论计算结果符合良好，这说明所开发的工具箱是可靠的。     

In2O3纳米孔材料的制备及其甲醛气敏性能研究

以In(NO3)3·4.5H2O为主要原料,采用溶剂热法成功地制备出In2O3纳米孔材料.采用X射线粉末衍射、透射电子显微镜等对样品的物相和形貌进行了表征和分析,并系统研究了其气敏性能.结果表明,成功合成的六方相In2O3纳米孔材料,其孔径小于17nm,孔道形状复杂且相互连通,以该材料制成的气敏元件对甲醛有很好的气敏性能,对50×10-6甲醛的灵敏度高达23.6.     

新的微晶白云母资源的开发及其粉体材料的应用

按白云母结晶大小及主要用途重新划分了白云母矿床的工业类型 ,并概述了不同类型矿床的产出特征 ,分析研究了具有显微结晶的块云母、绢云母、伊利石等矿物粉体材料的主要性能 ,及其在多种工业领域应用取得的部分成果 ,证实了具有功能性的微晶白云母粉体材料的应用前景十分广阔     

产品开发过程的并行机理及应用研究

对产品开发过程的并行机进行了讨论,系统地阐述了并行工程的４种特征,并进行了定性和定量分析,为实施并行工程提供了理论依据。在此基础上,设计并开发了并行设计系统。     

论地对空雷达干扰系统在局部战争中的作用及其发展

文章介绍了从地对空干扰机的发展概况,从单一干扰轰炸瞄准雷达,发展成地对空干扰系统和系列,可以干扰空载作战飞机雷达、导弹制导雷达、精密制导雷达、预警机雷达、星载探测雷达等,分析了这些雷达的干扰原理、干扰方法和干扰机的布局。文章对新体制雷达的干扰压制系数进行了分析,导出各类新体制雷达的干扰压制系数表达式,并提供了计算机仿真和实际试验的结果。文章分析了90年代以来两次现代化局部战争,地对空干扰系统若能发挥作用,将使被入侵国家的损失率下降,使入侵者的损失率升高。地对空干扰系统具有攻防兼备的立体干扰系列功能,需要经费较低,很适合于第三世界国家的需求,具有广泛的发展前景。     

Prediction of the Service Life of Rolling Bodies According to the Development of a Subsurface Crack

Within the framework of the fracture mechanics of solid bodies under the conditions of rolling-contact fatigue, we study the paths of propagation of a subsurface crack and determine the residual service life of the rolling surfaces (in terms of their crack resistance) under the conditions of dry friction. The stress intensity factors and growth paths of an initially rectilinear crack are analyzed depending on its orientation, location, and length and on the friction coefficient f (f = 0.2–0.4) for the rolling bodies in contact under the assumption that the crack propagates according to the mode-I mechanism. We establish the ranges of the indicated parameters in which the crack is completely open (its lips are not in contact). Some features of propagation of horizontal cracks and formation of spalling in the rolling bodies are discovered. It is shown that it is difficult for a horizontal crack to appear on the surface according to the (mode-I) mechanism of normal tension. The residual service life of the subsurface layers of rolling bodies made of 75KhGST rail and 9KhF roll steels and weakened by subsurface cracks is evaluated.     

Modeling and Optimization of a Microscale Capacitive Humidity Sensor for HVAC Applications

This paper presents a comprehensive numerical study of the performance of a capacitive humidity sensor for heating, ventilation, and air conditioning (HVAC) applications. The proposed sensor comprises a sensing layer sandwiched between an array of top and bottom electrodes. A combination of both parallel plate and interdigitated electrode arrangements is considered to achieve their distinctive advantages. Polyimide is used as the humidity sensing material due to good sensing characteristics and aluminum is used as the electrode material because of the ease of fabrication. A layer of polyimide covers the top electrodes to provide protection from atmospheric contamination thus improving durability. The influence of relative humidity on the dielectric constant of the sensing layer is determined theoretically using the models of Looyenga and Shibata The model is validated by comparing model predictions with experimentally measured data for a previously reported capacitive humidity sensor. The model is then used to simulate and predict the performance of the proposed humidity sensor. The effects of design configuration, sensing layer thickness, electrode polarity, electrode width and thickness, and electrode gap are studied. The influence of operating conditions including relative humidity, temperature and voltage is investigated. Based on the simulation results, the optimum design configuration is identified.     

The Development and Applications of Collagen-Based Biomedical Materials and Its Relevant Theory

正In this paper,the structure and properties of collagen,the rationale of collagen modification,the isoelectric point theory of collagen and its aggregation,and the multi-level collagen aggregates and its level division methods,etc,are clarified systematically.Meanwhile,the development progress of colla-     

氧化锆材料的特性及在结构陶瓷中的应用和发展

综述了氧化锆材料的某些应用特性、在结构陶瓷中的应用发展和目前氧化锆材料制备的技术问题.