一种新颖的表面空心微光阱阵列

提出了采用四台阶相位光栅与微透镜阵列组合产生一种新颖的表面空心微光阱阵列的方案，研究了表面空心微光阱阵列的光强分布，计算了相应的光学囚禁势，并讨论了该微光阱阵列在原子分子光学中的潜在应用.研究表明当用1W的YAG激光照射时，在1cm²面积上可产生近10⁴个空心光阱，每个光阱具有较小的囚禁体积和较大的有效光强及其强度梯度，对⁸⁵Rb原子的光学囚禁势可达190μK.如此深的光阱足以囚禁冷原子或冷分子，并可用于实现全光型原子或分子玻色-爱因斯坦凝聚，甚至制备新颖的光学晶格等. 关键词： 空心光阱 冷原子或冷分子 光学晶格     

Structural, magnetic properties and photoemission study of Ni-doped ZnO

Nickel-doped ZnO (Zn_1−xNi_xO) have been produced using rf magnetron sputtering. X-ray diffraction measurements revealed that nickel atoms were successfully incorporated into ZnO host matrix without forming any detectable secondary phase. Ni 2p core-level photoemission spectroscopy confirmed this result and suggested Ni has a chemical valence of 2+. According to the magnetization measurements, no ferromagnetic but paramagnetic behavior was found for Zn_0.86Ni_0.14O. We studied the electronic structure of Zn_0.86Ni_0.14O by valence-band photoemission spectroscopy. The spectra demonstrate a structure at ∼2 eV below the Fermi energy E_F, which is of Ni 3d origin. No emission was found at E_F, suggesting the insulating nature of the film.     

Rapidity dependence of charged antihadron to hadron ratios in Au+Au collisions at sqrt[s(NN)]=200 GeV

We present ratios of the numbers of charged antihadrons to hadrons (pions, kaons, and protons) in Au+Au collisions at sqrt[s(NN)]=200 GeV as a function of rapidity in the range y=0-3. While the ratios at midrapidity are approaching unity, the K(-)/K(+) and p;/p ratios decrease significantly at forward rapidities. An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from mu(B) approximately 130 MeV at y=3 to mu(B) approximately 25 MeV at y=0.     

Experimental long-distance decoy-state quantum key distribution based on polarization encoding

We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102 km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75 km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2, and 0.6 for the light sources in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation.     

Low temperature dependence of elastic moduli and internal friction for the glassy alloy Zr55Cu30Al10Ni5

Longitudinal and transverse wave velocities, eight kinds of elastic parameters, and dilational and shear internal frictions of Zr₅₅Cu₃₀Al₁₀Ni₅ glassy alloy were simultaneously measured as a function of temperature in the range from 77 to 373 K, using an ultrasonic pulse method. The inflections at around 150 K for wave velocities, anisotropy factor and Poisson's ratio, and the 150 K peak of shear friction seem to correspond to one topological change (pseudo‐transition) associated with an interatomic readjustment or vacancy rearrangements. The behaviors from 77 to 125 K and 125 to 373 K are due to thermal relaxation of squeezed free volumes and entropy elasticity associated with vibrational motions of clusters, respectively, accompanied by an increase in atomic distance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ag偏离化学计量比Ag1-xPb18SbTe20材料的热电传输性能

采用熔融-淬火-放电等离子体烧结制备了Ag偏离化学计量比Ag1-xPb18SbTe20(x=0,0.25,0.50,0.75)样品,研究了Ag含量对样品热电传输性能的影响.结果表明,随Ag含量降低,样品中出现少量第二相Sb2Te3,样品载流子浓度增加到5×1018cm-3后不再增加.样品载流子迁移率随Ag含量降低先降低后增加,随着温度增加,载流子散射机理由电离杂质散射转变为声学波散射.随Ag含量降低,样品电导率增加而Seebeck系数降低,热导率增加.     

介质阻挡放电中的能量转换过程研究

研究了介质阻挡放电过程中的电流强度、电场强度以及电荷分布的演变规律，并对能量转换性质进行了分析.研究结果表明，在一个放电脉冲过程中，外加驱动电源所作的功、电场能量的增量均与起始时刻的壁电荷密度有关，而气体中放电电流所作的功即沉积于气体中的能量与起始时刻的壁电荷密度、放电电流的具体波形无关. 关键词： 介质阻挡放电 壁电荷 动力学过程 能量转换     

基于Si掺杂Sb2Te3薄膜的相变存储器研究

采用磁控三靶(Si，Sb及Te)共溅射法制备了Si掺杂Sb₂Te₃薄膜，作为对比，制备了Ge₂Sb₂Te₅和Sb₂Te₃薄膜，并且采用微加工工艺制备了单元尺寸为10μm×10μm的存储器件原型来研究器件性能.研究表明，Si掺杂提高了Sb₂Te₃薄膜的晶化温度以及薄膜的晶态和非晶态电阻率，使得其非晶态与晶态电阻率之比达到10⁶，提高了器件的电阻开/关比；同Ge₂Sb₂Te₅薄膜相比，16at% Si掺杂Sb₂Te₃薄膜具有较低的熔点和更高的晶态电阻率，这有利于降低器件的RESET电流.研究还表明，采用16at% Si掺杂Sb₂Te₃薄膜作为存储介质的存储器器件原型具有记忆开关特性，可以在脉高3V、脉宽500ns的电脉冲下实现SET操作，在脉高4V、脉宽20ns的电脉冲下实现RESET操作，并能实现反复写/擦，而采用Ge₂Sb₂Te₅薄膜的相同结构的器件不能实现RESET操作. 关键词： 相变存储器 硫系化合物 2Te₃薄膜')" href="#">Si掺杂Sb₂Te₃薄膜 SET/RESET转变     

可吸入颗粒物在驻波声场中运动的可视化研究

采用可视化实验的方法,拍摄可吸入颗粒在驻波声场中的运动轨迹.根据拍摄结果,分别采用标尺测量、颗粒重力沉降特性和声波夹带特性计算颗粒粒径.实验表明,可吸入颗粒在声团聚室中受到声波夹带、重力作用和粘性力的影响.计算结果说明,利用声波夹带特性可以准确计算颗粒粒径,颗粒的漂移现象是由漂移力引起.