微波除冰方法研究

为解决我国北方寒冷地区冬季道路积冰不易清除的问题,提出了应用微波加热清除道路积冰的设想.通过实验证实了冰不易吸收微波,而路面材料能够吸收大量微波.因此,微波能够透过冰层加热路面,使贴近路面的冰层融化,消除冰层与路面之间的结合力,然后就可以很容易地利用除冰机械对其清除,这样,就消除了纯机械除冰的弊病.     

Modeling power and intermodulation behavior of microwave transistors with unified small‐signal/large‐signal neural network models

This article presents a detailed procedure to learn a nonlinear model and its derivatives to as many orders as desired with multilayer perceptron (MLP) neural networks. A modular neural network modeling a nonlinear function and its derivatives is introduced. The method has been used for the extraction of the large‐signal model of a power MESFET device, modeling the nonlinear relationship of drain‐source current I_ds as well as gate and drain charge Q_g and Q_d with respect to intrinsic voltages V_gs and V_ds over the whole operational bias region. The neural models have been implemented into a user‐defined nonlinear model of a commercial microwave simulator to predict output power performance as well as intermodulation distortion. The accuracy of the device model is verified by harmonic load‐pull measurements. This neural network approach has demonstrated to predict nonlinear behavior with enough accuracy even if based only on first‐order derivative information. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 276–284, 2003.     

A comparison of 18 winter seasons of in situ and passive microwave-derived snow water equivalent estimates in Western Canada

The Meteorological Service of Canada (MSC) has developed an operational snow water equivalent (SWE) retrieval algorithm suite for western Canada that can be applied to both Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) data. Separate algorithms derive SWE for open environments, deciduous, coniferous, and sparse forest cover. A final SWE value represents the area-weighted average based on the proportional land cover within each pixel. The combined SSM/I and SMMR time series of dual polarized, multichannel, spaceborne passive microwave brightness temperatures extends back to 1978, providing a lengthy time series for algorithm assessment. In this study, 5-day average (pentad) passive microwave-derived SWE imagery for 18 winter seasons (December, January, February 1978/79 through 1995/96) was compared to SWE estimates taken from a distributed network of surface measurements throughout western Canada.Results indicated both vegetative and snowpack controls on the performance of MSC algorithms. In regions of open and low-density forest cover, the in situ and passive microwave SWE data exhibited both strong agreement and similar levels of interannual variability. In locations where winter season SWE typically exceeded 75 mm, and/or dense vegetative cover was present, dataset agreement weakened appreciably, with little interannual variability in the passive microwave SWE retrievals. These results have important implications for extending the SWE monitoring capability of the MSC algorithm suite to northern regions such as the Mackenzie River basin.     

土壤样品的微波消解及其痕量铀的分析

对3个土壤样和2个放射性河床沉积物的国家标准物质进行了微波消解，又采用TOPO萃取和液体荧光法分析了样品中的铀含量，并将分析结果与国家标准方法GB11220．2-89的分析结果进行了比较。结果表明，微波消解法与国家标准方法一样，均不能实现土壤的全部消解，但与国家标准方法相比较，微波消解速度快，所需试剂量少，且易于实现定量控制，铀回收率高，分析精度高。对不溶物进行X射线能谱分析发现，其主要组成为铝、钛及过渡金属的氟化物或氧化物。同位素质谱分析表明，国家标准物质GBW08304中的^234U，^235U均比天然丰度低，另一个国家标准物质GBW08304a中铀的同位素分布与天然组成基本一致。     

多云多雨地区遥感初探

多云多雨地区是指以年平均降水量不小于800mm、气候湿润、降水丰沛、年晴天日数少于50天、常年云雨覆盖的包括陆地与海洋的广大湿润地区。这也包括人口增长迅速、城市化进程显、经济最为活跃的地区。由于天气条件的影响使光学遥感在这些地区的应用受到了很大限制，而具有全天候工作能力的雷达遥感数据具有广阔的应用前景。本简要阐述了多云多雨地区遥感的特点和意义，分析了遥感技术尤其是微波遥感技术在这一地区各领域的应用前景，指出了相关基础设施建设的紧迫性以及服务机制转变的重要性，并提出了将多云多雨地区遥感与区域科学系统研究相联系的观点。     

微波数据通讯的关键设备

应用NOKIA PCM复接器，将江西铜业公司所属矿山的局域网数据通过微波传输，本文介绍了微波数据通讯系统关键设备配置以及与企业管理网互连的解决方法。     

微波固化环氧树脂(E44/DDM)的热性能及膨胀性能

利用微波辐照固化环氧E44／二苯甲烷二胺(DDM)体系，考察了固化温度、固化时间以及微波功率之间的关系，分析了固化过程。利用FT-IR、DSC、热膨胀仪分别表征了体系的固化度、玻璃化转变温度(Tg)、热分解温度以及热膨胀系数(α)。结果表明，与热固化过程相比，微波能显著提高E44／DDM的固化速度，缩短凝胶化时间。且微波固化物具有较高的热分解温度和较低的线膨胀系数α。     

纳米硬质合金烧结技术进展

介绍了用于纳米硬质合金烧结的压力烧结、场辅助烧结、微波烧结、二步烧结等新技术，在评价各种烧结方法的基础上，以实验依据充分论证了普通真空烧结在纳米硬质合金制备中的可行性。     

含CeO2助催化剂的钴酞菁分子筛的微波合成及催化H2O2分解的研究

采用微波辐射在KX分子筛内原位合成了以CeO2为助剂的钴酞菁，将微波加热合成与传统加热合成进行了比较，用IR、XRD对合成产物进行了表征。考察了产物对过H2O2分解的催化活性。