Lifetime distribution of spontaneous emission from line antennas in two-dimensional quasi-periodic photonic crystals

We investigate the lifetime distribution functions of spontaneous emission from line antennas embedded in finite-size two-dimensional 12-fold quasi-periodic photonic crystals. Our calculations indicate that two-dimensional quasi-periodic crystals lead to the coexistence of both accelerated and inhibited decay processes. The decay behaviors of line antennas are drastically changed as the locations of the antennas are varied from the center to the edge in quasi-periodic photonic crystals and the location of transition frequency is varied.

Compact universal logic gates realized using quantization of current in nanodevices

This paper proposes novel universal logic gates using the current quantization characteristics of nanodevices. In nanodevices like the electron waveguide (EW) and single-electron (SE) turnstile, the channel current is a staircase quantized function of its control voltage. We use this unique characteristic to compactly realize Boolean functions. First we present the concept of the periodic-threshold threshold logic gate (PTTG), and we build a compact PTTG using EW and SE turnstiles. We show that an arbitrary three-input Boolean function can be realized with a single PTTG, and an arbitrary four-input Boolean function can be realized by using two PTTGs. We then use one PTTG to build a universal programmable two-input logic gate which can be used to realize all two-input Boolean functions. We also build a programmable three-input logic gate by using one PTTG. Compared with linear threshold logic gates, with the PTTG one can build digital circuits more compactly. The proposed PTTGs are promising for future smart nanoscale digital system use.

Spontaneous emission lifetime distribution of infinite line antennas in two-dimensional photonic crystals with finite size

The authors calculate the lifetime distribution functions of spontaneous emission from infinite line antennas embedded in two-dimensional disordered photonic crystals with finite size. The calculations indicate the coexistence of both accelerated and inhibited decay processes in disordered photonic crystals with finite size. The decay behavior of the spontaneous emission from infinite line antennas changes significantly by varying factors such as the line antennas' positions in the disordered photonic crystal, the shape of the crystal, the filling fraction, and the dielectric constant. Moreover, the authors analyze the effect of the degree of disorder on spontaneous emission. (c) 2007 American Institute of Physics.

基于Linux的USB驱动程序实现

由于Linux良好的开放性和USB总线极佳的通用性 ,USB设备在Linux操作系统中得到了广泛的应用。文中首先介绍Linux驱动程序的架构 ,然后介绍USB设备 ,重点说明USB驱动程序的实现

FET ACTIVE SLOTLINE NOTCH ANTENNAS FOR QUASI-OPTICAL POWER COMBINING

A new active antenna structure with applications in quasi-optical power combining is described. The active antenna combines a slotline FET oscillator with a notch antenna. The new structure was successfully used to create both E-plane and H-plane linear arrays as well as a 2-D array. Preliminary results of radiation patterns and the power combining efficiencies of the arrays are discussed.

Universal Biot number determining stress duration and susceptibility of ceramic cylinders to quenching

A universal Biot number, which not only describes the susceptibility of ceramic cylinders to quenching but also determines the duration that ceramic cylinders are subjected to thermal stress during thermal shock, is theoretically obtained. The analysis proves that thermal shock failure of ceramic cylinders with a Biot number greater than the critical value is a rapid process, which only occurs in the initial heat conduction regime. The results provide a guide to the selection of ceramic materials for thermostructural engineering, with particular reference to thermal shock.

基于USB接口和CPLD技术的CAMAC机箱控制器

介绍了基于U SB接口技术和CPLD技术的智能型的CAM AC机箱控制器的设计,该控制器设计简单,开发周期短,运行高效可靠,支持短周期。

基于以太网和USB技术的CAMAC机箱控制器

介绍了基于以太网技术和USB接口技术的智能型的CAMAC机箱控制器的设计,该控制器支持网络接口和USB接口,能够方便快捷的构成高速数据获取系统,运行高效可靠,且支持CAMAC短周期。

A Simple, Universal Colorimetric Assay for Endonuclease/Methyltransferase Activity and Inhibition Based on an Enzyme-Responsive Nanoparticle System

An enzyme responsive nanoparticle system that uses a DNA-gold nanoparticle (AuNP) assembly as the substrate has been developed for the simple, sensitive, and universal monitoring of restriction endonucleases in real time. This new assay takes advantage of the palindromic recognition sequence of the restriction nucleases and the unique optical properties of AuNPs and is simpler than the procedure previously described by by Xu et al. (Angew. Chem. Int. Ed. Engl. 2007, 46, 3468-3470). Because it involves only one type of ssDNA modified AuNPs, this assay can be directed toward most of the endonucleases by simply changing the recognition sequence found within the linker DNA. In addition, the endonuclease activity could be quantitatively analyzed by the value of the reciprocal of hydrolysis half time (t(1/2)(-1). Furthermore, our new design could also be applied to the assay of methyltransferase activity since the methylation of DNA inhibits its cleavage by the corresponding restriction endonuclease, and thus, this new methodology can be easily adapted to high-throughput screening of methyltransferase inhibitors.

USB插头式微型电化学分析仪的研制及应用

研制了一种基于通用串行总线(USB)接口的微型电化学分析仪(μECS)。仪器采用了20位数模转换器和24位模数转换器,输出电位分辨率达到10μV;输出电位范围为-5～+5V;电流测量范围为1nA～5mA。软件支持循环伏安法等各种常用电化学方法。对仪器主要参数进行了测试,其电流灵敏度小于50pA;输入阻抗大于1011Ω;电位误差小于1mV;电流测量误差小于1%。利用μECS进行了金电极上自组装单分子层(SAM)电化学特性的研究。

USB接口技术在便携式医疗仪器中的应用

USB是一种新型的计算机接口规范,它由于具有传输速度快、可靠性高、易于连接等优点而被广泛应用于目前的PC外围设备中。文章介绍了Philips公司的PDIUSBD12芯片和Atmel公司的ATmega128芯片在便携式心电监测仪上的应用,并给出了相应固件程序的编写方法。