通信领域2G、3G、4G技术专利申请状况分析

【】移动通信技术的发展日新月异,随之相应的专利申请量也日益增多,本文对移动通信领域2G、3G、4G技术在中国的专利申请状况进行了分析,给出了2G、3G、4G技术在中国的专利申请量分布,介绍了申请人排名,分析了通信领域主要申请人在中国的历年申请状况。     

二维Fisher准则函数在区域生长算法中的应用

本文针对传统区域生长算法中“种子”和“相似性准则”不能自适应获得的缺点,将二维Fisher准则函数算法[1]应用到区域生长算法中,根据图像特征,利用二维阈值,自动确定“种子”和“相似性准则”。实验表明,该算法不仅利用了二维Fisher准则函数算法的优点,而且也使区域生长算法具有自适应性,对荧光磁粉图像具有较好的分割效果。     

基于J2EE的实验报告管理系统的设计与实现

随着网络技术的不断发展以及在教学管理工作中的应用,在高校建立实验报告管理系统就显的十分必要。讨论了基于J2EE平台的实验报告管理系统的设计和实现。此系统设计采用B/W/L/E的结构及模式-视图-控制器的设计模式。系统界面友好、性能优良、通用性和安全性都很好。系统的运用将减轻教学管理工作的负担,提高教学管理工作效率。     

High Purity and Large-scale Preparation of β-Ga2O3 Nanowires and Nanosheets by CVD and Their Raman and Photoluminescence Characteristics

Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre coated（111） silicon substrates with chemical vapor deposition（CVD） technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope（SEM）, X-ray diffraction（XRD）, selected area electron diffraction （SAED） and transmission electron microscope（TEM）. Raman spectrum reveals the typical vibration modes of Ga2O3 The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence（PL） emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGaO excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor liquid-solid（VLS） and vapor-solid（VS） mechanisms.     

网络播放及其管理技术

介绍了网络播放技术的相关内容,包括流媒体（Streaming Media）技术、流媒体传输流程、流媒体解决方案、流媒体系统;分析了P2P技术的特点,并以典型的P2P文件交换软件为例,介绍P2P模式的几种主要形式,CDN技术及其网络的设计的两种思路。另外介绍了保护多媒体内容免受未经授权的播放和复制的数字版权管理（DRM）的工作原理及实现方式。     

Physical study of the dissipated power area in high electron mobility transistors for thermal modelling

The hot area in power transistors due to the power dissipation is determined from a 2D-hydrodynamic model. The power is calculated everywhere in the device from the knowledge of the physical quantities (current density, electric field). The hot area is determined accurately to be coupled to a thermal modelling giving the temperature everywhere in the device [J. Park, M.-W Shin, C.-C. Lee, Thermal modeling and measurement of GaN-based HFET devices, IEEE Electron Device Lett. 24(7) (2003) 424-426 [1]; J.-C Jacquet, R. Aubry, H. Gérard, E. Delos, N. Rolland, Y. Cordier, A. Bussutil, M. Rousseau, S.L. Delage, Analytical transport model of AlGaN/GaN HEMT based on electrical and thermal measurement, 12th GAAS Symposium, Amsterdam, 2004, pp. 235-238 [2].]. The method is applied to HEMTs (high electron mobility transistors) based on GaAs or GaN. It is shown that the hot area depends on the bias conditions and on the transistor gate recess topology.     

基于FETI的2维阵列电磁特性分析

应用有限元分裂互连方法(FETI)对2维阵列的电磁散射特性进行分析,将原求解区域划分成若干个不重叠的子区域,并根据其特性划分成9种类型。在相邻区域公共面上采用电场连续性条件,保证电场分量的连续性。对每个子域进行独立的有限元分析,通过公共面上的电流进行区域信息交换,确保相邻面上的区域耦合能够准确地被表示。此算法在保持有限元法计算精度的同时,大大减少了计算时间和内存消耗,拓展了有限元方法在周期结构上的应用。     

超临界CO_2萃取香料精油的研究

本文对熏衣草、百里香、野百里香和迷迭香４种香料单独或两种香料混合超临界ＣＯ２萃取和分级分离香料精油的工艺可行性，以及采用ＧＣ，ＧＣ－ＭＣ对萃取物的主要成分分析进行了初步研究。从两种香料混合物中革取所获产率等于从每种香料所获产率之平均值，混合萃取明显提高精油和树脂两种产品的分离效率，两种香料混合物的萃取物所含的主要成分与两种香料单独萃取的成分相同，但浓度有明显差别。     

Improvement of the cell performance in the ZnS/Cu(In,Ga)Se2 solar cells by the sputter deposition of a bilayer ZnO : Al film

ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se₂ (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd.     

A new wave approach for signal and noise modelling of microwave/mm-wave FET based on Green's function concept

Based on the active coupled line concept, a novel approach for calculating the noise performance of microwave/mm-wave field-effect transistors (FETs) is proposed. The voltage and current Green's functions are introduced to determine the correlation matrix of the FET. Some results using this approach have been presented for a microwave MESFET.