FTU技术在公路建设供电电网中的应用分析

在对公路建设用电供电电网负荷变化情况调查的基础上,基于柔性输电理论,分析在供电电网中适时采用FTU技术,提高供电质量和供电可靠性的必要性及可行性,提出解决公路建设用电的具体实施方案,为公路建设供电改造提出决策依据.     

一种火灾检测的新方法

传统的离子式、吸气式、光电式等烟雾检测器在大空间中检测烟雾时,会受到发射信号与接收信号之间的距离、平面角度、精确对准等限制,无法对整个空间的烟雾状况进行描述。新的方法通过监测区域的摄像机拍摄的视频图像序列,进行小波变换,分析图像帧在时域和空域的频率特性,来确定被监测区域是否有火灾烟雾的发生。实验证明该方法不受空间高度、热障、易爆、有毒等环境的限制,并且有灵敏度高、抗干扰力强、适用范围广等特点。     

电压闪变的小波多分辨率分析

从实时监测电压波动和闪变信号的角度出发,研究了基于小波多分辨率分解的电压闪变分析方法;利用小波变换的多分辨率分析方法,对电压闪变信号进行了检波与分解,并提取出电压波动信号的频率和幅值。从而得到反映电压闪变的参数。     

基于Web2.0环境下的图书馆2.0刍议

文章简要阐述了Web2.0的概念,在此基础上重点论述了图书馆2.0的内涵、原则以及Web2.0技术的应用实践,最后对图书馆2.0提出了两点思考.     

大负荷运动状态下男运动员部分生理、心理指标测试分析

采用台阶实验法，测试大负荷运动状态下男运动员的心率、肺活量、闪烁频率、平衡能力等生理、心理指标。结果表明：40cm高、每min上下40次台阶实验中，被试心率均可达180bs／min以上，该实验可作为研究大负荷运动状态下测试生理、心理机能的方法；在大负荷运动状态下，运动后即刻心理机能提高；运动后即刻与休息5min后的心理指标比较显示，心理机能可能存在延迟下降的现象。     

Neural adaptations with sport-specific resistance training in highly skilled athletes

The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to record interpolated twitches. The pattern of neural drive was measured by analysing isometric torque–time curves and electromyographic (EMG) characteristics during the performance of rapid isometric contractions at maximal effort. The volume and intensity of training were varied at 4-weekly intervals to systematically emphasize the development of strength, power and motor performance in 14 highly skilled track and field athletes (e.g. discus, hammer, javelin, shot put and weight). Knee extension strength increased significantly by 15% during steady

maximal isometric contractions and by 24% during rapid isometric contractions at maximal effort after the 16-week training programme (P < 0.05). Increases in EMG amplitude and rate of EMG activation indicated that improvements to the pattern of neural drive occurred with sport-specific resistance training (P < 0.05). The maximality and pattern of neural drive did not change in the control group.     

Design of CMOS Mixer with Complementary Transconductance

<正>A current bleeding CMOS mixer with complementary transconductance stage is presented in this paper.The conversion gain of the mixer is increased and the flick noise of the mixer is reduced by inserting the PMOS to form current bleeding circuit in Gilbert mixer.The circuit is designed through SMIC 0.18um CMOS process,the LO frequency is 1.571GHz,RF frequency is 1.575GHz,simulation results show the conversion gain of the mixer is 18.5 dB,SSB NF is about 9.59dB,and third-order input intercept point(IIP3) is-4.6dBm.The mixer consumes 7.8 mA at 1.8 V power supply and the size of the whole layout is 0.73mm×0.68 mm.     

One-branch zero-IF wireless receiver topology with multiphase local oscillator

This paper proposes a one-branch zero-IF receiver topology, which samples the I and Q signals of the modulated RF carrier with one signal path by means of a multiphase local oscillator. The suggested one-branch re- ceiver works without matching problem, and it is also capable of cancelling out the flicker noise and DC-offset when the local oscillator is configured to the four-phase mode. The one-branch receiver saves much area and power com- pared with the traditional two-branch ones. All of the advantages above make the one-branch receiver topology a promising architectural candidate for low-power and low-cost RF CMOS receiver designs. Keywords： RF CMOS; zero-IF; flicker noise; image rejection; low-power; IQ matching     

用数字技术消除电视中的闪烁现象

现代电视中存在比较严重的行间闪烁和大面积闪烁现象。本文论述了利用数字技术将模拟信号变成数字信号,再利用数字信号的存贮功能以及不同的存取速度来消除电视中闪烁现象的方法。针对大面积闪烁,采用提高场频方法,针对行间闪烁,将隔行扫描成逐行扫描,从而消除了电视中的闪烁现象。