Au丝键合改为Cu丝键合技术

现阶段Au丝作为内引线一直占着键合的主导地位,由于Cu丝具有优良的电性能和价格优势,随着键合技术的发展,以Cu丝代替Au丝作为键合用内引线已经成为必然,封装行业许多厂家正热衷于将原有的Au丝键合设备进行改造,但还存在这样那样的问题。以Au丝键合改为Cu丝键合的技术研究为出发点,首先介绍了键合技术的发展,然后通过工艺调整和设备改造,使得Cu丝作为内引线能够代替Au丝在该设备上使用,同时达到了节约生产成本,节约资金的目的。对改造过程中的气体流量、压力、功率、焊接时间等参数问题进行了详细地阐述,同时对芯片、键合劈刀等也做了相应调整,使得改造后的检测结果完全满足产品要求。大力推进以Cu丝替代Au丝键合技术,可节约生产成本,提高键合强度,增强导电率、导热率等,具有重要的经济技术效益,必将迎来封装业的又一次大变革。     

一种用于接收机的低功耗自动增益控制环路

This paper proposes a new structure to lower the power consumption of a variable gain amplifier (VGA) and keep the linearity of the VGA unchanged. The structure is used in a high rate amplitude-shift keying (ASK) based IF-stage. It includes an automatic gain control (AGC) loop and ASK demodulator. The AGC mainly consists of six-stage VGAs. The IF-stage is realized in 0.18 μ m CMOS technology. The measurement results show that the power consumption of the whole system is very low. The system consumes 730 μ A while operating at 1.8 V. The minimum ASK signal the system could detect is 0.7 mV (peak to peak amplitude).     

半无限大生物组织中光子分布规律的研究

光子在生物组织中的传播和分布问题, 是影响光动力疗法治疗结果的重要因素之一。本文给出了蒙特卡罗方法模拟半无限大均匀生物组织中光子分布的计算方法和模拟结果, 分析了半无限大生物组织中光子分布规律。结果表明, 生物组织的光学性质强烈影响光在组织中的分布情况。具有低散射系数, 低吸收系数和高各项异性因子的生物组织, 有利于光子深入均匀地分布其中。力图为光动力疗法的临床应用提供了有效的诊断和治疗依据。     

智能终端安全漏洞现状浅析

在智能终端迅速发展和普及的同时,与之相关的安全漏洞也开始逐渐成为威胁终端安全的一大因素。文章主要围绕智能终端安全漏洞的现状展开分析,介绍了智能终端安全漏洞的分类和形成机理,并且给出了应对漏洞的防范措施。     

基于Radon-STFT的DSSS系统线性调频干扰对消

提出一种基于Radon-STFT的DSSS系统线性调频干扰对消算法,仿真实验表明,该方法可以在较大的动态范围内有效地抑制线性调频干扰。与基于STFT的抑制算法相比,其参数估计精度大大提高;与基于WHT的抑制算法相比,该方法在多分量条件下效果更为突出,其运算量也显著降低。     

Thermoelectric Properties of Multifilled Skutterudites with La as the Main Filler

Bulk multifilled n- and p-type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT = 0.76 for p-type La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ and ZT = 1.0 for n-type La_0.3Ca_0.1Al_0.1Ga_0.1In_0.2Co_3.75Fe_0.25Sb₁₂ skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ sample. The thermal stability of the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C.     

500kW/380V国产钻机专用变频器的研制与应用

本文主要介绍国产钻机专用变频器的研制与应用。首先简要分析国外变频器在钻机应用中存在的缺点,并与国产变频器做了比较,论述了变频钻机的优点:随后解析原钻机控制系统中存在的问题,我们针对这种状况在大庆市石油管理局井下钻井公司的配合下对该油田钻机进行了变频改造;随后论述了该系统的技术改造方案。现场运行情况表明,该变频系统性能好,可靠性高,操作方便,其各项指标均达到了改造的预期效果。我们相信变频器在油田钻机上的成功应用将会有广阔的市场前景和发展潜力。     

几种主流视频编码方式的性能比较和分析

随着多媒体通信技术的不断发展,不同的组织提出了许多不同特点的编码方法。文中回顾并分析了当前一些主流的编码机制,通过峰值信噪比(PSNR)和最小察觉差(JND)对主流视频编码技术的质量性能进行了比较。通过比较发现,使用客观的PSNR标准时,H．264/AVC的各方面性能要好于现在使用的视频压缩标准,但选择主观的JND标准可能会略微影响不同编码的性能。     

A sub-1 V high-precision CMOS bandgap voltage reference

A third-order, sub-1 V bandgap voltage reference design for low-power supply, high-precision applications is presented. This design uses a current-mode compensation technique and temperature-dependent resistor ratio to obtain high-order curvature compensation. The circuit was designed and fabricated by SMIC 0.18 μm CMOS technology. It produces an output reference of 713.6 mV. The temperature coefficient is 3.235 ppm/℃ in the temperature range of -40 to 120 ℃, with a line regulation of 0.199 mV/V when the supply voltage varies from 0.95 to 3 V. The average current consumption of the whole circuit is 49 μA at the supply voltage of 1 V.