Performance of Indoor Infrared Wireless CDMA Systems with Angle Diversity

Indoor infrared communication systems is one of the possible ways of offering data rates in excess of 100 Mbit/s without the need for wiring. Multiple users can share an infrared channel by code division-multiple access (CDMA) techniques. However, the CDMA system performance is limited by both background noise and co-channel interference. In this paper we study the use of angle diversity for mitigating the effects of the noise and interference. The system considered uses on-off shift keying modulation with multibeam transmitters and imaging receivers. The overall system performance for different diversity combining techniques is evaluated and compared to a system without diversity. Numerical results for a 2-user CDMA system indicate that signal to noise and interference ratio (SNIR) improvement (over systems with no diversity) of 5 dB is obtained for at least 50% of an ensemble of 10000 sample evaluations. The generalized selection combining (GSC)--a new diversity technique yet to be implemented for infrared systems--offers the best performance even with its reduced complexity.     

16信道0.35μmCMOS/VCSEL光发射模块

研究了垂直腔面发射激光器 (VCSEL)及其列阵器件的光谱特性、调制特性、高频特性及与微电子电路的兼容性 ,将 1× 16的VCSEL与CMOS专用集成电路进行多芯片组装 (MCM ) ,混合集成为 16信道VCSEL光发射功能模块 .测试过程中 ,功能模块的光电特性及其均匀性良好 ,测量的 - 3dB频带宽度大于 2GHz.     

高温酸化助排剂HC2-1的研究

为了满足高温油藏和深井酸化作业残酸返排的需要，通过表面活性剂的筛选和复配研究，得到了高温酸化助排剂HC2—1。其性能评价结果表明，HC2—1具有使用浓度低、表面活性高的特点，在20％的HCI溶液中，当其浓度为50mg／L时，表面张力为20．7mN／m；具有良好的耐温性能，在180℃下恒温48h，HC2—1仍保持较高的表面活性；具有良好的耐盐能力，加有HC2—1的20％HCl溶液和CaCO3反应至HCl完全消耗，整个反应过程体系无新相生成且表面张力基本不变；可增大酸液体系的润湿角，进一步降低毛细管阻力，使酸液返排率由46％提高到97％，在促进酸液返排的同时与原油不发生乳化反应。     

Hf-doped and NH/sub 3/-nitrided high-K gate dielectric thin film with least drain current degradation and flatband voltage shift

A novel technique to form high-K dielectric of HfSiON by doping base oxide with Hf and nitridation with NH/sub 3/, sequentially, is proposed. The HfSiON gate dielectric demonstrates excellent device performances such as only 10% degradation of saturation drain current and almost 45 times of magnitude reduction in gate leakage compared with conventional SiO/sub 2/ gate at the approximately same equivalent oxide thickness. Additionally, negligible flatband voltage shift is achieved with this technique. Time-dependent dielectric breakdown tests indicate that the lifetime of HfSiON is longer than 10 years at V/sub dd/=2 V.     

变频器的组成与常见故障及维修对策

本文介绍了变频器组成结构及相应故障与维修对策。     

PLC的大型牵伸卷绕机的应用研究

本文介绍了大型牵伸卷绕机的计算机控制系统，以西门子MMV型变频器为驱动装置，西门子PLC300为控制核心，根据西门子USS协议和MPI协议，实现PLC与变频器、TP27触摸显示屏的通信，取得了较高的控制精度和稳定性，充分满足生产过程的需要，具有广阔的应用前景。     

新产品研发是建陶企业可持续发展的核心

新世纪我国建陶企业在整个国民经济的带动下将进一步发展，入世后经济全球化的市场竞争格局，建陶企业只有走新产口研发之路，严格企业管理，才会在日趋激烈的市场竞争中得以生存和可持续发展。     

Speed superiority of scaled double-gate CMOS

Unloaded ring-oscillator simulations, performed with a generic process/physics-based compact model for double-gate (DG) MOSFETs and supplemented with model-predicted on-state currents and gate capacitances for varying supply voltages (V_DD), are used to show and explain the speed superiority of extremely scaled DG CMOS over the single-gate (e.g., bulk-Si) counterpart. The DG superiority for unloaded circuits is most substantive for low V_DD < ~1 V     

转炉溅渣护炉改质剂的开发研究

影响转炉溅渣护炉效果的关键因素是终渣成分的控制,采用改质剂对转炉终渣成分进行调整,降低渣中FeO含量和炉渣温度,提高MgO含量和炉渣熔点及粘度,有利于改善炉渣与炉衬的粘结效果,并提高溅渣层的耐蚀性能,缩短溅渣起孕时间,在一定程度上抑制炉渣中铁的氧化物与炉衬中石墨的反应.     

水泥生产中预加水成球微机控制系统

叙述水泥生产中以ＳＴＤ８０９８微机系统为核心组成的生料预加水成球控制系统的构成、工作原理及软件结构。该系统目前已在云阳钢铁厂水泥分厂投入使用，效果良好，成球合格率在９０％以上。