Texture and Magnetic Properties of Rolled Fe-6.5 wt.%Si Thin Sheets

Thin (0.20 mm) Fe-6.5 wt.%Si sheets have been successfully fabricated by the continuous rolling method. The designed rolling process parameters, including the initial hot-band grain size, grain size after intermediate annealing, cold rolling reduction, and cold rolling temperature, were selected to control the texture development. Dominant recrystallization η fiber [rolling direction (RD)// $ \left\langle {001} \right\rangle $ ] was achieved after high-temperature annealing. The produced Fe-6.5 wt.%Si thin sheets are promising alternatives for use in power electronics because of their magnetic properties from 400 Hz to 40 kHz.     

Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)₆Sn₅ intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)₆Sn₅ IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.     

Optical implementation of a polarization-independent bidirectional 3 × 3 optical switch

Based on the important role of optical switching in all-optical communications, a novel 3 × 3 optical switch is proposed using Phase Spatial Light Modulators (PSLM), Polarizing Beam-Splitters (PBS), mirrors, and Quarter-Wave Plates (QWP). This new configuration of optical switch has the advantages of being compact in structure, efficient in performance, and insensitive to polarization of the signal beam. Moreover, the functions of the 3 × 3 optical switch have been implemented bidirectionally in free-space. According to the routing-state table of the polarization-independent 3 × 3 optical switch, its operational processes are analyzed, and the results show that the experimental module of the 3 × 3 optical switch can connect an arbitrary output port to any input port beams. Simultaneously, the module is scalable to large array sizes and has the capability of reconfiguration. Therefore, it should be helpful in the design of a large-scale switching matrix.

原位生成(Al2O3)p/(Al-4wt.%Mg)复合材料的TEM观察

本文用TEM研究了原位反应方法制备的Al2O3增强铝基复合材料，发现在Al-4wt.%Mg基复合材料中的尖晶石型反应产物MgAl2O4以“界面AgAl2O4”，“弥散MgAl2O4”和“晶内MgAl2O4”三种形态存在，原位生成的Al2O3以“晶内MgAl2O4”为衬底形核长大，并在界面富集形成“界面MgAl2O4”。     

Electrical Conductivity and Dielectric Properties of Se85Te15−x Sb x (x = 0 at.%, 2 at.%, 4 at.%, and 6 at.%) Thin Films

The alternating-current (ac) conductivity and dielectric properties of Se₈₅Te_15?x Sb _x (x = 0 at.%, 2 at.%, 4 at.%, and 6 at.%) films are reported in this work. Thin films were deposited by thermal evaporation under base pressure of 10^?5 Torr. The films were well characterized by x-ray diffraction, differential scanning calorimetry, and energy-dispersive x-ray spectroscopy. The ac conductivity and dielectric properties have been investigated for the studied films in the temperature range from 297 K to 333 K and over the frequency range from 10² Hz to 10⁵ Hz. The experimental results indicate that the ac conductivity $ \sigma_{\rm{ac}} (\omega ) $ and the dielectric constant depend on temperature, frequency, and Sb content. The frequency dependence of $ \sigma_{\rm{ac}} (\omega ) $ was found to be linear with a slope lying very close to unity and is independent of temperature. This behavior can be explained in terms of correlated barrier hopping between centers forming intimate valence-alternation pairs. The density of localized states N(E _F) at the Fermi level is estimated. The activation energy $ \Updelta E(\omega ) $ was found to decrease with increasing frequency. The dielectric constant ε ₁ and dielectric loss ε ₂ were found to decrease with increasing frequency and increased with increasing temperature over the ranges studied. The maximum barrier height W _m for the studied films was calculated from an analysis of the dielectric loss ε ₂ according to the Guintini equation. The values agree with that proposed by the theory of hopping of charge carriers over a potential barrier as suggested by Elliott for chalcogenide glasses. The variation of the studied properties with Sb content was also investigated.     

A 3 V 110 μW 3.1 ppm/°C curvature-compensated CMOS bandgap reference

This paper presents design of a high-precision curvature-compensated bandgap reference (BGR) circuit implemented in a 0.35 μm CMOS technology. The circuit delivers an output voltage of 1.09 V and achieves the lowest reported temperature coefficient of ~3.1 ppm/°C over a wide temperature range of [?20°C/+100°C] after trimming, a power supply rejection ratio of ?80 dB at 1 kHz and an output noise level of 1.43 μV $ \sqrt {\text{Hz}} $ at 1 kHz. The BGR circuit consumes a very low current of 37 μA at 3 V and works for a power supply down to 1.5 V. The BGR circuit has a die size of 980 μm × 830 μm.     

时效处理快速凝固Mg-5 wt.％Sn合金微观结构的电子显微分析

用显微维氏硬度仪、X射线衍射仪（ XRD）、扫描电子显微镜（ SEM）和透射电子显微镜（ TEM）研究分析了快速凝固Mg?5 wt?％Sn合金条带的时效硬化规律。实验结果表明,快速凝固Mg?5 wt?％Sn合金在593 K温度下时效3 h后达到峰值硬度。时效后峰值硬度下的快速凝固Mg?5 wt?％Sn合金中有β?Mg2 Sn相颗粒析出,大多数的析出相β?Mg2 Sn颗粒分布在晶界,少部分析出相β?Mg2 Sn颗粒分布在晶粒内部。在593 K温度下时效3 h后的合金中观察到析出相β?Mg2Sn 颗粒与基体α?Mg 的一种新取向关系：（202261）β／／（0110）α,（7236）β／／（0001）α,[512]β／／[2110]α。     

Effect of the Second Sintering Temperature on the Microstructure and Electrical Properties of PbNb2O6-0.5 wt.%ZrO2 Obtained via a Two-Step Sintering Process

Lead metaniobate PbNb₂O₆ ceramics with addition of 0.5 wt.% ZrO₂ (PNZr) were processed via the conventional solid-state reaction method and a two-step sintering process. A lower second sintering temperature efficiently prevents volatilization of Pb²⁺. X-ray diffraction patterns indicate that the samples are of orthorhombic ferroelectric phase. Scanning electron microscopy shows that abnormal grain growth was restrained. The dielectric anomalies around 300°C caused by oxygen vacancies are effectively reduced.     

基于 GSVD 的分布式 MIMO 雷达测向算法

针对分布式多输入多输出（multi-input multi-output, MIMO）雷达测向中存在的数据信息提取不充分、运算量偏大等问题，开展了基于广义奇异值分解（generalized singular value decomposition, GSVD）的测向算法研究，以提高低信噪比条件下的角度估计性能。首先，建立了分布式阵列MIMO雷达回波信号的统一化表征模型；其次，将分布式MIMO雷达系统接收阵列数据的多线程GSVD问题转换为一个联合优化问题，运用交替最小二乘（alternating least squares, ALS）技术实现阵列信号流行矩阵的拟合，并引入子空间类算法实现目标角度联合估计；最后，对优化问题增加l1范数约束，避免了每次迭代中进行的奇异值分解运算，降低了算法运算量。仿真实验从角度联合估计、均方误差、运算时间等方面验证了所提算法的有效性。     

优化Windows 3.x

不要光等着Windows 95给你带来更佳的性能。在等待的同时也应该最大限度地利用Windows 3.x。下面有一些忠告和技巧可以帮助你为你的老朋友注入一些新的生气。 清理硬盘 删除.BAK和.TMP之类的文件、运行CHKDSK或SCANDISK、去除你的硬盘碎片你会注意到有明显的性能改进。 清理字体 打开你的字处理器,并且数一数可用字体的清单。删除不必要的字体。 得到某些帮助 一个最著名但却不为人所真正了解的Windows附属应用程序程序就是Windows Help引擎。它甚至也有自己的图标,即一个黄颜色的大问号。当然只要在任何附属应用程序程序或应用程序程序中打开它,你就可以得到帮助。但是你也许希望浏览几个帮助文件而不去打开每一个存取它们的应用程序。如果真想如此的话,     

Windows 3.x界面设计

目前,Windows已成为PC机的标准图形用户界面,它使程序员跳出了DOS下菜单、鼠标等烦琐的界面设计工作,驰骋于Windows的丰富资源当中。但是,标准的Windows 3.x窗口仅仅是一个呆板的白色平面,使人觉得总是有些单调。 Borland公司意识到了这一点,从而通过它的“Borland风格”式的改进极为成功地赋予Windows应用程序一个崭     

3.大规模逻辑集成电路

所谓数字逻辑使用的大规模集成电路,就是在电子计算机本体,即在信息处理装置中所使用的逻辑电路大规模集成化。一般说来,其逻辑结构将因信息处理装置的性能与结构,或设计者的个性而异,从而呈现出多种多样的形式逻辑电路构成的信息处理系统,通过这些逻辑电路的有机结合而构成一个整体,进行数据处理的是控制电路部分,它象神经系统那样地分布在整个装置中。使用数据传输通路来进行连结。因此,在提高集成度实现大规模集成电路时,在那个部分进行逻辑分割便是重要的课题。如果逻辑划分不合理,大规模集成电路的品种数或输入输出端数便会增多,在成本方面或电子计算机的维护方面都很不利。一般来说,必须充分考虑成本和性能两方面,选择最佳的逻辑分割。     

Design of 3 mm Band Hopping Frequency Synthesizer

With the combination of the technique of PLL, DDS and multiplier, a 3 mm band hopping frequency synthesizer with high frequency stability and low phase noise has been presented, which is characterized by nice performances. The design includes an X-band hopping frequency source, which is the LO for millimeter-wave harmonic mixing. Once the interim frequency being locked by the phase-locked loop, the corresponding 3 mm hopping frequency would be locked. Measurement result shows that the output frequency is 93.24～93.748 GHz, the bandwidth is 508 MHz, the stepping frequency is 4 MHz, and the phase noise is about -82dBc/Hz at 10 kHz offset.     

OPTOELECTRONICS LETTERS Vol.3. 2007 Total Contents

NIU Nan-hui, WANG Huai-bing, LIU Jian-ping, LIU Nai-xin,XING Yan-hui, HAN Jun, DENG Jun, and SHEN Guang-di 0001 Effects of growth interruption on the properties of InGaN/ GaN MQWs grown by MOCVD 0004 Design of tunneling injection quantum dot lasers JIA Guo-zhi, YAO Jiang-hong, SHU Yong-chun, and WANG Zhan-guo 0007 Design and fabrication of ultrasmall arrayed waveguide grating multiplexers based on Si nanowire waveguides DAI Dao-xin, LIU Liu, ZHEN Sheng, and HE …     

Current-Mode Universal Biquadratic Filter with Five Inputs and Two Outputs Using Two Multi-Output CCIIs

A current-mode universal biquadratic filter with five input terminals and two output terminals is presented. The proposed circuit uses two multi-output second generation current conveyors, two grounded capacitors and three resistors. The new circuit offers the following advantages: use of the minimum number of active components, orthogonal controllability of resonance angular frequency and quality factor, use of grounded capacitors and the versatility to synthesize any type of active filter transfer functions.     

Influence of 0.03?wt.% Carbon Black Addition on the Performance of Sn-3.5Ag Lead-Free Solder

In an effort to improve the performance of lead-free solder, Sn-3.5?wt.%Ag (Sn-3.5Ag) solder alloy with 0.03?wt.% carbon black was prepared under high pressure (5.5?GPa) and high temperature (1200°C). We have investigated the microstructure, melting behavior, and mechanical properties of the alloy using x-ray diffraction, differential scanning calorimetry (DSC), Vickers hardness testing, tensile testing, and scanning electron microscopy (SEM). The melting point was found to be unchanged, while the hardness and the tensile strength increased with the addition of carbon black. SEM images showed that the average thickness of the intermetallic compound (IMC) layer decreased with the addition of carbon black, indicating improvement in solder joint reliability.