Observation of two multiwave mixing processes via dual optical pumping channels

Based on double optical pumping channels,we experimentally study the competition between two coexistent six-wave mixing(SWM) processes falling into two electromagnetically induced transparency windows by scanning the frequency of the probe field in two similar five-level atomic systems of 85Rb.By blocking one optical pumping channel unrelated to the four-wave mixing(FWM) process,one SWM process,together with the FWM process,generated by a conjugated small-angle static grating could be observed in the spectrum.Moreover,the other SWM process obtained by blocking the first SWM channel is also observed together with the FWM process in a lower N-type four-level subsystem.These experimental results agree well with theoretical predictions.     

Effect of speckle pattern on laser Doppler velocimeters

The effect of speckle pattern on laser Doppler velocimeters is studied theoretically and experimentally. We have found that dynamic speckle patterns can cause error in velocity measurement. Increasing sampling time and using proper signal processing circuits can eliminate this bad effect caused by speckle pattern.The accuracy of velocity measurement is better than 2.1％ in a wide velocity range(4.66-468.86 mm/s)when speckle effects are taken into account.     

GRIN透镜干涉仪光学系统模型和分析

较完整地提出GRIN透镜干涉仪的数学模型,分析了光学系统处于六种不同模态下的特点,讨论了有关结构因素,特别是GRIN透镜长度对干涉仪工作性能的影响,有关分析和相关结论可作为GRIN透镜干涉仪系统设计和测量计算的依据。     

实现冷原子或冷分子囚禁的可控制光学四阱

提出了一种利用单光束照明二元π相位板与透镜组合系统实现冷原子或冷分子囚禁的可控制光学四阱新方案.计算了四阱的光强分布，讨论了从光学四阱到双阱或到单阱的演化过程，并导出了四阱和双阱几何参数、光强分布、强度梯度及其曲率与光学透镜系统参数间的解析关系.研究表明，通过相对移动二元π相位板可实现光学四阱到双阱或到单阱的连续双向演化，获得了四阱或双阱间距与相位板移动距离的关系.该方案在超冷原子物理、冷分子物理、原子光学、分子光学和量子光学，甚至量子计算及信息处理等领域中有着广阔的应用前景. 关键词： 二元π相位板 可控制光学四阱 原子分子囚禁 原子光学     

适用于深亚微米NMOSFET ESD效应的非本地传输模型

分析了深亚微米NMOSFET在ESD应力下的非本地传输特性，分析说明了速度过冲效应可以增大漏端电流，改变器件特性. NMOSFET能量弛豫时间与器件中该点的电场、载流子速度和载流子能量密切相关，从而不能再近似为一个常数.利用蒙特卡罗仿真方法得到电子能量弛豫时间和电子高场迁移率与电子能量的关系表达式，并使用上述模型进行了ESD器件仿真，与实验结果的对比显示，使用该能量弛豫时间模型和高场迁移率模型可以得到准确的器件I-V曲线. 关键词： 静电放电 速度过冲 能量弛豫时间     

Localized excitations with and without propagating properties in （2＋1）-dimensions obtained by a mapping approach

By means of an extended mapping approach, a new type of variable-separation excitation is derived with two arbitrary functions in a (2 1)-dimensional modified dispersive water-wave system. Based on the derived variable-separation excitation, abundant nonpropagating and propagating solitons such as dromions, rings, peakons and compactons are revealed by selecting appropriate functions in this paper.     

Electrochemical Polymerization of Azure Blue II and Its Electrocatalytic Activity toward NADH Oxidation

IntroductionOver 30 0dehydrogenasesareknowntobedependentonthenicotiamideadeninedinucleotidecoenzymeinitsreduced (NADH )andoxidized (NAD+)forms ,andamonitoringofenzymaticallygeneratedNADHisthebasisforthedevelopmentofbiosensorsfortheselecteddehydro genase .Hence ,thedetectionofthiscoenzymeisimpor tantinbothpracticalanalysisandbiochemicalsynthesis .ThereportedoverpotentialforoxidationofNADHatpH7 0isabout 1 1Vatcarbonand 1 3Vatplatinumelec trodes .1,2 Itisgenerallyacceptedthatthedirecto…     

Continuum Structures at the Second Dissociation Limit of Hydrogen Molecules

We describe near-threshold high-resolution spectra and continuum resonance dynamical behaviour of all three stable hydrogen isotopic variants, and finally obtain improved values for the dissociation energies of hydrogen molecule and its ion. The second dissociation limit is determined by analysing the onset of the vibrational continuum.