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1.
Wedding……     
兄弟结婚了,朋友结婚了,朋友的朋友结婚了;男的结婚了,女的结婚了,不男不女的也结婚了;有感情的结婚了,没感情的结婚了,认识不认识的结婚已经无所谓了……  相似文献   

2.
    
江湖最近挺乱. 金融海啸了,经济危机了;奥巴马当选了,杨致远下课了;三聚氰胺走了又来了,"林书记"来了又走了;百度乱卖广告被央视曝光了,首富黄光裕涉嫌违法被拘查了;国家开始上万亿的花钱了,央行敢于一百零八个基点的降息了!  相似文献   

3.
本文提出了一种无需检测电感电流及其过零点的简单数字控制方案,实现了临界连续模式功率因数校正器的控制。取得了功率开关管的ZVZCS,消除了整流二极管和快恢复二极管的反向恢复带来的损耗,提高了变换器的效率和可靠性;另外,数字控制器克服了模拟IC控制器的开关频率限制问题,消除了输入电流的低频畸变,提高了功率因数;同时,也降低了输入电感的值,降低了成本的同时提高了功率密度。为实现中小功率数字控制功率因数校正器的产品化提供了一个良好的解决方案。  相似文献   

4.
王红萍 《电子测试》2012,(10):66-69,81
针对采用芯片nRF905的LED屏无线通信,分别给出了上位机和下位机的系统框图,分析了系统的功耗,比较了无线模块和串口通信的通信速率,验证了系统的可行性,设计了串口通信协议,为保证数据质量,设计了数据通信协议,针对串口数据的nRF905分包转发,设计了无线芯片通信协议,例举了状态机的5种状态,介绍了状态间的转换条件,巧妙地编程设计了通信数据的定时器检查,论述了基于状态机的嵌入式单片机软件编程。  相似文献   

5.
在当今的社会中,人们已经离不开电子通信了,其作为了一个新兴产业,并得到了良好的应用,对各行各业起到了促进作用,同时,传统的产业收到了冲击。我国的电子通信发展较快,达到了先进的水平,不过,由于发展时间较短,存在很多不足之处,拉低了整体水平。特别是干扰问题,严重影响了电子通信的发展。本文对电子通信进行了概述,探讨了干扰要素,并且,提出了相关的应对策略。  相似文献   

6.
铝电解电容器技术的新进展   总被引:3,自引:3,他引:0  
详细讨论了电子技术的发展对铝电解电容器的性能要求,提出了其技术对策,分析了存在的技术瓶颈,找出了它的技术出路,探讨了它的技术难点,给出了当前我国铝电解电容器行业的技术现状,指出了未来发展方向。  相似文献   

7.
ATM原理概论     
介绍了ATM技术的框架,详细描述了ATM的协议栈;介绍了ATM的信元结构,描述了信元边界判定算法,指出了特殊信元的结构;叙述了常用的ATM适配层协议AAL1-AAL5;简单介绍了ATM的维护功能;最后指出了影响ATM性能的重要参数。  相似文献   

8.
介绍了大功率固态调制器电路常用的拓扑结构,讨论了开关直接串联与加法器叠加两种拓扑结构的特点.设计了基于绝缘栅双极性晶体管的加法器结构的大功率固态脉冲调制器,探讨了该类型大功率调制器的关键技术,介绍了调制器系统参数,并与国内外大功率调制器进行了对比.重点阐述了调制器实验,给出了实验结果,并对实验结果进行了分析.最后探讨了加法器结构的大功率固态脉冲调制器的优势及应用潜力.  相似文献   

9.
阐述了紫外通信的优劣性,分析了紫外通信综合实验平台信号源设计的必要性,设计了紫外通信实验平台的系统结构方案,分析了各部分功能,给出了信号源设计的要求,选用了信号产生芯片MAX038与ICL8038,探讨了两者工作原理,对比了两者的优劣性,根据系统信号源参数要求设计了MAX038外围器件工作参数,最后使用OrCAD Pspice完成了电路的仿真,并通过2个结果分析验证了电路的可行性,这对系统的构建具有十分重要的指导意义。  相似文献   

10.
一种采用电容共用技术的DC-DC开关电源软启动电路   总被引:1,自引:0,他引:1       下载免费PDF全文
开关电源DC-DC转换器已经在各种电子设备中取得了广泛的应用。软启动电路保证了DC-DC转换器的正常启动,防止了器件的损坏。从理论上分析了软启动电路原理,设计了一种新型的开关电源软启动电路,该电路引入了电容共用方法,通过与频率补偿电容共用节省了软启动电容,降低了应用成本。并给出了具体电路实现,Spectre仿真结果验证了这种电路的可行性。  相似文献   

11.
基于56F803型DSP的大功率超声波电源的研究   总被引:3,自引:0,他引:3  
针对大功率超声波电源高精度、高功率输出的特点,对超声波电源控制策略进行了改进.提出一种基于56F803型DSP的频率跟踪与功率调节相结合的周期分段移相控制策略,研究了基于此控制方法的超声波电源.  相似文献   

12.
The drift mobility of charge carriers in glassy semiconductors of the Se-As system doped with Ag, Au, and Tl is investigated. A considerable increase in the electron drift mobility is established in samples doped with Ag. These results are explained within a model of charged defects. Fiz. Tekh. Poluprovodn. 32, 803–805 (July 1998)  相似文献   

13.
The development of a 750-GHz Schottky varactor diode frequency tripler having a measured output power and efficiency of more than 120 μW and 0.8% at a frequency of 803 GHz is described. The output powers and efficiencies are the highest reported for this frequency. The 750-GHz tripler mount is analyzed and optimized using a scaled model of the mount. Measurements of the embedding impedance seen by the device, using the model, are compared with theoretical values  相似文献   

14.
高精度定位与精细化导航的实现,至少需要具备两个条件:高精度定位网络、终端定位芯片或板卡。在高精度定位网络准备之际,终端板卡的能力成了重要关注点。基于此,文章依托中移智行的高精度定位精品网络,选择了三款主流板卡进行测试,对板卡接入中国移动高精度定位网后的功效与性能进行验证。测试表明,在中国移动高精度定位网络的良好支撑下,K700(三系统单频)、K706(三系统六频)、K803(四系统十三频)均能很好地支撑交通参与者获得良好的高精度定位服务。  相似文献   

15.
Gold nanoclusters (GNCs) attract increasing attention due to their potential applications in sensing, catalysis, optoelectronics, and biomedicine. Herein, the formation of highly fluorescent glutathione (GSH)‐capped GNCs is achieved through the delicate control of the reduction kinetics and thermodynamic selection of the Au(I)–SG complexes. Furthermore, the GNCs‐based nanoprobes are developed by the covalent coupling folic acid (FA) and PEG (polyethylene glycol) on the surface of GNCs directly, followed by trapping photosensitizer (chlorin e6, Ce6) within PEG networks and attaching to the GNCs surface. The fabricated nanoprobes (Ce6@GNCs‐PEG2K‐FA) possess a uniform particle size (hydrodynamic diameter ≈6.1 ± 1.2 nm), without affecting the yield of singlet oxygen of the trapped Ce6. In vitro studies show the enhanced cellular uptake and satisfactory photodynamic therapy (PDT) effectiveness toward MGC‐803 cells when compared with free Ce6. The biodistribution and excretion pathway studies of the nanoprobes in MGC‐803 tumor‐bearing nude mice reveal their superior penetration and retention behavior in tumors, while the preserved features of renal clearance and stealthy to reticulo‐endothelial system are mainly attributed to the small hydrodynamic diameters and the FA‐capped PEGylated ligands. The enhanced PDT efficacy and the nontoxicity to mice provide an exciting new nano‐platform with promising clinical translational potential.  相似文献   

16.
We report an automatic frequency control (AFC) for an optically pumped far infrared (FIR) ring laser applicable for high resolution THz sideband spectroscopy by mixing a fraction of the laser power and a harmonic of a phase-locked synthesizer on a planar Schottky diode. We achieve a relative frequency accuracy of about 0.5 kHz rms at 803 GHz ( 15 NH 3 ) and about 1 kHz rms at 1626.6 GHz (CH 2 F 2 ) over hours of lock time. The absolute frequency accuracy is estimated to be about 5 kHz at 1626.6 GHz.  相似文献   

17.
采用单辊快淬法制备了Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5非晶合金,在不同温度下对两种合金进行了热处理。利用差热分析仪(DTA)、X射线衍射仪(XRD)和振动样品磁强计(VSM)等仪器对两种合金的热性能、微观结构和磁性能进行了测试分析。结果表明在Fe78Co2.5Zr7Nb2B10Cu0.5合金的晶化过程中存在预结晶效应,而在Fe81Zr7Nb2B10合金的晶化过程中没有。Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5合金经803 K退火后,分别有α-Fe和α-Fe(Co)相从非晶基体中析出。随退火温度的升高,两种合金的比饱和磁化强度(Ms)变化趋势相似,但矫顽力(Hc)变化趋势明显不同。  相似文献   

18.
5V单电源供电的低噪声宽带放大器   总被引:1,自引:0,他引:1  
徐玲 《电子设计工程》2011,19(7):159-161,164
以单片机MSP430F449为控制核心,设计了一个5 V单电源供电的低噪声宽带放大器。采用单位增益稳定低噪声运放OPA820作为前级放大,高速运放THS3091作为末级放大,其中利用DC-DC变换器TPS61087将5 V电压转化为18 V从而为末级放大电路供电。此外,系统还采用12位高速A/D转换器ADS803实现了测量并数字显示放大器输出电压峰峰值的功能,测量误差小于5%。本系统最高电压增益达到43 dB,上限及下限截止频率达到15 MHz和20 Hz,在50Ω负载上,最大不失真输出电压峰峰值为4.2 V。系统的输出噪声小于200 mV。  相似文献   

19.
Interactions of germanium self-interstitials with interstitial oxygen atoms in Ge crystals have been studied by combining experimental and theoretical methods. Self-interstitials were created in oxygen-rich Ge crystals by irradiation with MeV electrons at 80 K, and I–O-related complexes were studied by means of infrared absorption spectroscopy, while the density functional theory was used to model structures, local vibrational modes and electronic properties of IO and I2O centers. It is argued that two absorption lines at 674 and 602 cm−1, which develop upon annealing of irradiated Ge:O crystals in the temperature range 180–220 K, are related to IO complexes, while another set of bands at 713 and 803 cm−1 is related to I2O. Those assignments are supported by the comparison with the calculated local vibrational modes of the defects.  相似文献   

20.
Though urgently needed, high-efficiency near-infrared (NIR) organic light-emitting diode (OLED) is still rare due to the energy-gap law. Formation of intermolecular charge-transfer aggregates (CTA) with nonadiabatic coupling suppression can decelerate non-radiative decay rates for high-efficiency NIR-OLEDs. However, the aggregation effect of CTA is still not fully understood, which limits the rational design of CTA. Herein, two CTA molecules with a same π-framework but different terminal substituents are developed to unveil the aggregation effect. In highly ordered crystalline states, the terminal substituents substantially affect the molecular packing motifs and intermolecular charge-transfer states, thus leading to distinct photophysical properties. In comparison, in amorphous states, these two CTA demonstrate similar photophysical behaviors and properties due to their similar molecular packing and intermolecular interactions as evidenced by molecular dynamics simulations. Importantly, the formations of amorphous CTA trigger multifunction improvements such as aggregation-induced NIR emission, aggregation-induced thermally activated delayed fluorescence, self-doping and self-host features. The non-doped OLEDs demonstrate NIR emissions centered at 788 and 803 nm, and high maximum external quantum efficiencies of 2.6% and 1.5% with small efficiency roll-off, respectively. This study provides deeper insight into the aggregation effect of CTA and lays a foundation for the development of high-efficiency NIR non-doped OLEDs.  相似文献   

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