A detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription polymerase chain reaction

A rapid, sensitive and highly specific detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription-polymerase chain reaction (RT-PCR) has been developed. Two pairs of PCR primers were synthesized according to the cloned cDNA sequences of the GCHV-861 strain. For each primer combination, only one specific major product was obtained when amplification was performed by using the genomic dsRNA of GCHV-861 strain. The lengths of their expected products were 320 and 223 bp, respectively. No products were obtained when nucleic acids other than GCHV-861 genomic RNA were used as RT-PCR templates. To assess the sensitivity of the method, dilutions of purified GCHV-861 dsRNA total genome (0.01 pg up to 1000 pg) were amplified and quantities of as little as 0.1 pg of purified dsRNA were detectable when the amplification product was analyzed by 1.5% agarose gel electrophoresis. This technique could detect GCHV-861 not only in infected cell culture fluids, but also in infected grass carp Ctenopharyngodon idellus and rare minnow Gobiocypris rarus with or without hemorrhagic symptoms. The results show that the RT-PCR amplification method is useful for the direct detection of GCHV.

Fabrication and Characterization of High Power InGaN Blue-Violet Lasers with an Array Structure

InGaN/GaN multi-quantum-well-structure laser diodes with an array structure are successfully fabricated on sapphire substrates. The laser diode consists of four emitter stripes which share common electrodes on one laser chip. An 800-mu m-long cavity is formed by cleaving the substrate along the < 1 (1) over bar 00 >. orientation using laser scriber. The threshold current and voltage of the laser array diode are 2A and 10.5 V, respectively. A light output peak power of 12W under pulsed current injection at room temperature is achieved. We simulate the electric properties of GaN based laser diode in a co-planar structure and the results show that minimizing the difference of distances between the different ridges and the n-electrode and increasing the electrical conductivity of the n-type GaN are two effective ways to improve the uniformity of carrier distribution in emitter stripes. Two pairs of emitters on a chip are arranged to be located near the two n-electrode pads on the left and right sides, and the four stripe emitters can laser together. The laser diode shows two sharp peaks of light output at 408 and 409 nm above the threshold current. The full widths at half maximum for the parallel and perpendicular far field patterns are 8 degrees and 32 degrees, respectively.

White light emission from fiber pigtailed laser module

We fabricated a phosphor-conversion white light using an InGaN laser diode that emits 445 nm and phosphor that emit in the yellow. The InGaN laser diode was coupled to an optical fiber firstly and the phosphor was excited by the laser light output from the fiber. At 350 mA injection current the luminous flux and the luminous efficacy was 73 lm and 42.7 lm/W, respectively. The luminance was estimated to be 50 cd/mm(2). The relationship of the luminous flux and the luminous efficacy of the white light with injection current were measured and discussed.

Photoluminescence characteristics of GaAsSbN/GaAs epilayers lattice-matched to GaAs substrates

The photoluminescence (PL) characteristics of GaAsSbN/GaAs epilayers grown by molecular beam epitaxy (MBE) are carefully investigated. The results show that antimony (Sb) incorporation into GaNAs material has less influence on the N-induced localization states. For the same N concentration, GaAsSbN material can reach an emission wavelength near 1.3 mum more easily than GaInNAs material. The rapid thermal annealing (RTA) experiment shows that the annealing induced rearrangement of atoms and related blueshift in GaAsSbN epilayers are smaller than those in GaNAs and GaInNAs epilayers. The GaAsSbN material can keep a longer emission wavelength near 1.3 mum-emission even after the annealing treatment. Raman spectroscopy analysis gives further insight into the structure stability of GaAsSbN material after annealing. (C) 2004 Elsevier Ltd. All rights reserved.

Thermal entanglement in two qutrits system

The thermal entanglement in a two-qutrit system with two spins coupled by exchange interaction is investigated in terms of the measure of entanglement called "negativity". It is found that the thermal entanglement is present and evolvements symmetrically between both ferromagnetic and antiferromagnetic exchange couplings with the temperature. Moreover the critical temperature at which the negativity vanishes increases with the exchange coupling constant J. From the temperature and magnetic field dependences we demonstrate that the temperature and the magnetic field can affect the feature of the thermal entanglement significantly.

Influences of initial nitridation process on the optical and structural characterization of GaN layer grown on sapphire (0001) by metalorganic chemical vapor deposition

In this paper. we investigate the influences of the initial nitridation of sapphire substrates on the optical and structural characterizations in GaN films. Two GaN samples with and without 3 min nitridation process were investigated by photoluminescence (PL) spectroscopy in the temperature range of 12-300 K and double-crystal X-ray diffraction (XRD). In the 12 K PL spectra of the GaN sample without nitridation, four dominant peaks at 3.476, 3.409 3.362 and 3.308 eV were observed, which were assigned to donor bound exciton, excitons bound to stacking faults and extended structural defects. In the sample with nitridation, three peaks at 3.453, 3.365. and 3.308 eV were observed at 12 K, no peak related to stacking faults. XRD results at different reflections showed that there are more stacking faults in the samples without nitridation.

Self-assembled InAs/GaAs quantum dots and quantum dot laser

Systematic study of molecular beam epitaxy-grown self-assembled In(Ga)As/GaAs, In-AlAs/AlGaAs/GaAs, and InAs/InAlAs/InP quantum dots (QDs) is demonstrated. By adjusting growth conditions, surprising alignment, preferential elongation, and pronounced sequential coalescence of dots under the specific condition are realized. Room-temperature (RT) continuous-wave (CW) lasing at the wavelength of 960 nm with output power of 1 W is achieved from vertical coupled InAs/GaAs QDs ensemble. The RT threshold current density is 218 A/cm(2). An RT CW output power of 0.53 W ensures at least 3 000 h lasing (only drops 0.83 db). This is one of the best results ever reported.

基于LSM框架的审计系统的设计与实现

LSM是Linux系统的通用访问控制框架,在安胜安全操作系统V4.0中,我们在这一访问控制框架的基础上做了适当的扩展并设计实现了安全审计系统.该安全审计系统与安胜安全操作系统V2.0的审计系统相比,性能得到了很大的提高.另外,隐蔽通道会绕过系统的安全策略来进行非法的数据流传输,我们在审计系统中进行了实时检测和报警.

基于手势和草图的概念设计协同交互的研究

基于手势和草图的交互模式提供了一种自然和谐的方式来支持概念设计协同操作,促进协同工作系统的发展与应用.基于以用户为中心的设计,比较了不同方式的概念设计过程,提出了基于手势和草图的协同设计方法,进一步讨论了以草图为设计过程中的信息载体,分析了草图信息模型;基于手势操作,提出了协同上下文感知的概念和协同设计上下文描述模型;最后分析并给出面向同步编辑的草图交互设计和双向约束求解方法.所提出的协同设计方法自然简便,提高了设计效率,改善了人机交互方式.

MST在手写汉字切分中的应用

手写汉字切分是根据输入笔迹的空间位置关系进行汉字部件的合并切分,形成完整的汉字笔划以便进行识别处理.综合利用了汉字部件的结构位置关系和笔划的空间位置关系,根据笔划的最小生成树(minimalspanningtree,简称MST)对联机连续手写输入汉字进行切分,取得了较好的切分结果.切分的准确率超过91.6%.

炼油企业CIMS研究与实践

结合“九五”期间CIMS实施的经历 ,从炼油企业所面临的新问题出发提出了实施CIMS的必要性 ,以炼油企业增值链为基础描述了炼油企业CIMS的一般结构和实施原则 ,最后提出一个实例 ,简要介绍了CL -CIMS的功能结构。