(LaxBi1-x)2Ti2O7薄膜X射线光电子能谱研究

采用化学溶液沉积(CSD)工艺在Si(100)衬底上制备了Bi2Ti2O7(BTO(和(LaxBi1-x)2Ti2O7(BLT(铁电薄膜，薄膜的X射线衍射(XRD)结果显示其具有较好的结晶性，运用X射线光电能谱仪(XPS)对薄膜的结构进行了研究，分析结果表明，薄膜中氧空位的出现影响了其相的稳定性，通过掺La可以改善其性能。     

Odd-Periodic and Periodic Complementary binary sequences

Two or more sequences are called an Odd-Periodic Complementary binary sequences Set (OPCS) if the sum of their respective odd-periodic autocorrelation function is a delta function. In this paper, the definition of OPCS is given and the construction method of OPCS is discussed. The relation of the OPCS with the Periodic Complementary binary sequences Set (PCS) is pointed out, and some new PCSs are obtained based on such relation.     

红外激光薄膜表面缺陷研究

薄膜缺陷是影响红外激光薄膜元件抗激光损伤的重要因素之一,长期以来一直是人们关注和研究的问题。本文介绍了红外激光薄膜缺陷的种类、特点及成因,在此基础上,分析了不同厂家镀膜材料与不同镀膜速率对薄膜表面缺陷密度的影响,并且得出了镀制激光薄膜所需的合适材料与速率,最后利用有限元方法对典型的节瘤与陷穴缺陷受激光作用进行了模拟分析,结果表明:节瘤缺陷种子深度小且直径大的缺陷产生的温升与应力较大,陷穴缺陷随直径增大,其产生的温升与应力也较大。     

Characteristics of Schottky Barrier Junction Based on Hexagonal Microtube ZnO

Hexagonal microtube ZnO was firstly grown on single crystal p-Si (111) substrates by hydrothermal method, and fabricated Ag/n-ZnO and Au/n-ZnO Schottky junction. Schottky effective barrier heights were calculated by I-V measurement. It is confirmed that the presence of a large amount of surface states related possibly to lattice imperfections existed near the surface leads to the pinning of the surface Fermi level at 0.35 eV below the conduction-band edge. Then the fabricated Schottky barrier junctions are evaluated for their use as UV photodetectors.     

用于MEMS器件的键合工艺研究进展

随着MEMS器件的广泛研究和快速进步,非硅基材料被广泛用于MEMS器件中.键合技术成为MEMS器件制作、组装和封装的关键性技术之一,它不仅可以降低工艺的复杂性,而且使许多新技术和新应用在MEMS器件中得以实现.目前主要的键合技术包括直接键合、阳极键合、粘结剂键合和共晶键合.     

采用PECVD方法制作SiO2绝缘层的AlGaN/GaN MOS-HFET器件

为了进一步减小栅漏电,提高击穿电压,将MOS结构的优点引入ALGaN／GaN HEMT器件中,研制并分析了新型的基于AlGaN／GaN的MOS—HFET结构。采用等离子增强气相化学沉积（PECVD）的方法生长了50nm的SiO2作为栅绝缘层,新型的AlGaN／GaN MOS—HFET器件栅长1μm,栅宽80μm,测得最大饱和输出电流为784mA／mm,最大跨导为44．25ms／mm,最高栅偏压＋6V。     

基于蒙特卡洛滤波平滑的语音增强算法

本文在分析统计信号贝叶斯模型和语音信号的时变自回归(TVAR)模型的基础上,利用蒙特卡洛滤波及平滑方法,对语音信号的TVAR模型参数进行了估计,提出了一种有效的针对非平稳加性噪声影响下的语音增强算法.该算法可以很好的跟踪非平稳信号,同时引入对反射系数的判断,保证了跟踪的稳定性.实验表明,本文方法能很好的抑制背景噪声,提高信噪比,改善语音信号的听觉质量.     

基于移动代理的安全研究

移动代理计算模式较传统的分布式计算模式有明显的优势,而伴随它有诸多安全问题出现,这使得它没有得到十分广泛的应用。本文针对代理自身的安全问题,分析了代理可能受到的攻击,并提出了一个安全方案。     

基于电子现金的新型支付协议

本文提出了一种基于电子现金的新型支付协议,该协议通过第三方实时核算客户拥有的电子现金,但不进行实时转账。协议模型较好地克服了现有在线支付的交易瓶颈问题以及离线支付中电子现金容易被重用、伪造或篡改的问题,在交易过程中有效地保证了安全性,并且实现了电子现金的原子性、匿名性、可分割性和可验证性。     

A dual-mode analog baseband with digital-assisted DC-offset calibration for WCDMA/GSM receivers

A dual-mode analog baseband with digital-assisted DC-offset calibration(DCOC) for WCDMA/GSM receiver is presented.A digital-assisted DCOC is proposed to solve the DC-offset problem by removing the DC-offset component only.This method has no bandwidth sacrifice.After calibration the measured output residual offset voltage is within 5 mV at most gain settings and the IIP2 is more than 60 dBm.The baseband is designed to be reconfigurable at bandwidths of 200 kHz and 2.1 MHz.Total baseband gain can be programmed from 6 to 54 dB.The chip is manufactured with 0.13μm CMOS technology and consumes 10 mA from a 1.5 V supply in the GSM mode including an on-chip buffer while the core area occupies 1.2 mm~2.