几何位相非线性变化的实验研究

本文报道了Pancharatnam位相非线性变化的实验研究，实验结果与理论预言符合得很好。Pancharatnam位相的这种非线性可能在光开关中得到应用。     

Fe-B合金激光熔凝形成非晶态机理探讨

本文对激光表面熔区的显微组织进行了热力学和动力分析，提出一个简化的熔池中温度分布的物理模型，分析了非晶态形成过程。用ＣＷＣＯ２激光扫描Ｆｅ—Ｂ合金表面，得到１３０μｍ～２００μｍ厚度的非晶层，并对激光低速扫描时熔区再结晶点阵常数变化的有关数据进行了对比，对激光非晶态形成的条件及有关工艺参数进行了分析和讨论。     

Optimum filter banks for signal decomposition and its applicationin adaptive echo cancellation

The application of multirate filter banks in echo cancellation is investigated. The multiresolution algorithm is used to decompose the received sampling sequence into a number of components, and then, an adaptive algorithm is applied to cancel the echo in the received signal. In this paper, the performance of this method is discussed, from which optimal conditions for echo cancellation are established for the design of wavelet packet multiresolution decomposition. An efficient algorithm for designing such a set of optimal discrete filter banks is developed. The cases of optimal in-band and adjacent-band adaptive filtering are examined. Experimental results showed that the use of optimally designed multiresolution filter banks coupled with in-band or adjacent-band adaptive filtering is much more effective than the employment of commonly used wavelet filter banks. Furthermore, the use of the adjacent-band adaptive filtering algorithm has superior performance compared with that of the in-band filtering     

某石化企业电厂布袋除尘器的改造

分析了某石化企业自备电厂4号炉布袋除尘器运行过程中出现的问题,提出了相应的解决方法。经过改造后,设备运行良好。     

FGTO — A fine structured GTO-thyristor with improved switching characteristics

Contents A fine structured GTO thyristor, abbreviated FGTO, has been developed to improve the switching characteristics. The new device has a cathode finger width of only 20 m and can be turned off without a negative gate bias at an anode current level of more than 200 A/cm². The turn-off time can be shortened down tot _off 500 ns by increasing the negative gate current. A snubber circuit is not necessary to turn off the FGTO's. The maximum rate of rise of anode voltage du/dl reaches more than 10 kV/s. Analytical models are developed to describe the turn-off transients of the FGTO's. Good agreement between the theoretical and experimental results could be achieved.

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FGTO — Ein feinstrukturierter GTO-Thyristor mit verbessertem Schaltverhalten

Übersicht Zur Verbesserung des Schaltverhaltens ist ein feinstrukturierter GTO-Thyristor, abgekürzt FGTO, entwickelt worden. Dieses neue Bauelement hat eine Kathoden-streifenbreite von nur 20 m und kann ohne negative Gatevorspannung bei einer Anodenstromdichte von mehr als 200 A/cm² abgeschaltet werden. Die Abschaltzeit läßt sich durch Erhöhung des negativen Gatestroms bis zut _off 500 ns verkürzen. Beim Abschalten von FGTOs ist keine RC-Beschaltung erforderlich. Der maximale du/dl-Wert erreicht mehr als 10 kV/s. Zur Beschreibung des Abschalt-verhaltens von FGTOs werden analytische Modelle entwickelt, die eine gute Übereinstimmung mit den Meßergebnissen liefern.

     

分布式冷热电联产技术在新建三级医院中的应用

医院是重要的公共服务性场所,也是能源消耗的大户。有关资料表明,医院建筑能耗是一般建筑的1.6-2.2倍,其中电力消耗占了各项能源消耗总量中相当大的比例。作为上海郊区新建的三级医院,我院在设计之初就确定建设分布式冷热电联产系统,自2012年12月投入使用以来,此系统在降低能耗上优势明显,但也发现仍存在可以不断改进的地方。现就我院分布式冷热电联产技术的应用现状,就其概念、原理、特点、存在问题和解决措施作一介绍。     

Off-Grid DOA Estimation Via Real-Valued Sparse Bayesian Method in Compressed Sensing

A novel real-valued sparse Bayesian method for the off-grid direction-of-arrival (DOA) estimation is proposed in compressed sensing (CS). The off-grid model is reformulated by the second-order Taylor expansion to reduce modeling error caused by mismatch. To apply the Bayesian perspective in CS conveniently, complex data are addressed to yield a real-valued problem by utilizing a unitary transformation. By assuming that sources among snapshots are independent and share the same sparse prior, joint sparsity is exploited for DOA estimation. Specifically, a full posterior density function can be provided in the Bayesian framework. The convergence rate and convergence stability of the proposed method can be guaranteed in the iterative procedure. Simulation results show superior performance of the proposed method as compared with existing methods.     

海洋雨团的全极化SAR回波信号仿真研究

在海洋的合成孔径雷达图像中,降雨（雨团）通常能引起依赖于雷达频率和极化的形状不规则的亮暗斑状图案,影响着合成孔径雷达图像的正确解译。基于C.Melsheimer的双极化仿真方法,首次对海洋雨团C、X波段全极化合成孔径雷达归一化雷达后向散射截面积进行仿真。仿真结果补充了双极化仿真的不足,更加全面地揭示了海洋雨团合成孔径雷达回波在不同波段不同极化下的特点,有助于合成孔径雷达图像的正确解译和降雨定量化研究。     

基于Metasys系统车间空调机组自动化

为了实现我厂空调系统节能降耗、方便管理、达到工艺要求、提高经济效益等目标,我们选用Johnson Controls(美国江森自控)之Metasys系统对厂区车间的空调进行自控设计。     

基于PTS方法降低OFDM系统的峰均功率比

OFDM最主要缺点之一就是时域的大峰均功率比。为了降低大峰均比,PTS是最常用的方法之一,但传统的PTS方法是对频域数据进行IFFT运算后选择最优传输序列,一般需要多个IFFT,OFDM系统复杂度高。为了解决多IFFT这一问题,本文提出了一种新方法,即在频域里判决最优序列,而大大减少IFFT块的数目。