A low‐complexity single‐carrier frequency‐division multiple access transmitter

A framework for a computationally efficient single‐carrier frequency‐division multiple access (SC‐FDMA) transmitter is proposed in this paper. Compared with a wide system bandwidth, the uplink allocation for each user is supposed to be relatively small because of multiple user access, which makes each user's signal vector to be sparse. When the localized subcarrier allocation is used for SC‐FDMA, the inverse fast fourier transform can take advantage of the sparse user input vector to reduce its complexity. The analytical and simulation results show that the proposed framework can provide a significant complexity reduction compared with the conventional SC‐FDMA transmitter. Copyright © 2011 John Wiley & Sons, Ltd.     

Real‐Time Measurement of the Size Distribution of Diesel Exhaust Particles using a Portable 4‐stage Electrical Low Pressure Impactor

For this study, a 4 stage electrical low pressure impactor was designed to measure the real‐time size distribution of diesel particulate matter (DPM). For the performance evaluation, sodium chloride (NaCl) particles and dioctyl sebacate (DOS) particles were used. After evaluating the collection efficiency of each stage of the impactor, the size distributions of test particles were estimated using electrical current data and their inversion algorithm, and this was found to agree with the results obtained by a scanning mobility particle sizer (SMPS). For measurement of DPM, a common‐rail direct injection (CRDI) diesel engine, for engine speeds of 1,200 rpm and 1,500 rpm at 2.7 kgf·m, was used. Therefore, it was found that the size distribution of the DPM could be easily obtained, with the currents measured by the impactor and the data inversion algorithm, in less than 5 seconds. Furthermore, the effective density of the DPM could be obtained using the calculated results and the SMPS data.     

早期干预对极低出生体重早产儿智能发育的影响研究

目的 探讨早期干预对极低出生体重早产儿智能发育的影响,为极低出生体重早产儿的早期干预提供依据。方法 239 例极低出生体重早产儿为早产随访组,采用鲍秀兰早期教育资料制定的干预计划,进行系统干预,并与326 例失访的早产儿童以及与随访组相似的326 例正常儿童进行对照分析。采用Gesell 儿童发育量表等标准化工具进行发育评估。结果 早产随访组Gesell 儿童发育量表5 项均分、总发育商（developmental quotient,DQ）总分与早产失访组相比差异均有统计学差异（均P＜0.05）。结论 早期干预能显著促进极低出生体重早产儿的智能发育,提高患儿的生活质量。     

一款高性能时钟驱动器电路的设计

时钟器件芯片可以实现通信网定时同步、时钟产生、时钟恢复和抖动滤除、频率合成和转换、时钟分发和驱动等功能。在系统设计中,选用好的时钟驱动芯片,可以省去系统时钟树设计,既节省空间,又提高系统性能。介绍一款高性能时钟驱动器的集成电路设计方法,主要性能要求有:低传播延时、低输出偏斜、低输出抖动、抗电磁干扰能力、抗ESD能力,一一详述了达到各项要求的设计。     

接触面陷阱密度对a-InSnZnO薄膜晶体管器件电气性能的影响研究

We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering powers.The device with the smallest N_t of 5.68×10¹¹ cm^-2 and low resistivity of 1.21×10^-3Ω·cm exhibited a turn-on voltage(V_ON) of-3.60 V,a sub-threshold swing（S.S） of 0.16 V/dec and an on-off ratio(I_ON/I_OFF) of⁸ x 108.With increasing N_t,the V_ON,S.S and I_ON/I_OFF were suppressed to-9.40 V,0.24 V/dec and 2.59×10⁸,respectively.The V_TH shift under negative gate bias stress has also been estimated to investigate the electrical stability of the devices.The result showed that the reduction in N_t contributes to an improvement in the electrical properties and stability.     

High-speed low-power voltage-programmed driving scheme for AMOLED displays

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits.     

飞机交流电源测频电路低通滤波器的设计与仿真

针对型号研制过程中出现的交流电源频率测量出现跳变的问题,进行了故障定位和原因分析,并提出了解决方案。设计了适用于飞机交流电源系统频率测量电路的低通滤波器,对其特性进行了计算分析,并基于SIMULINK建立了滤波器的模型,进行了仿真验证,结果表明设计的滤波器是有效的。     

水情自动测报系统遥测站低功耗设计研究

针对水情自动测报系统运行环境和特点,分析了影响遥测站功耗的主要因素,详细阐述了器件选型、电源控制、远程通信、软件编程等关键环节进行低功耗设计的策略与实现方法。据此设计的数据采集器在现场得到广泛运用,验证了本方法的有效性和实用性。