Cooper对质心定向运动速度的空间分布规律及“邻近效应”

在零场下 ,由超导电流密度的两种表达形式 ,导出了超导载流子质心定向运动速度的空间分布规律 ,并由毕萨定律定性地解释了“邻近效应”     

固体核磁共振技术在锡硅分子筛表征中的应用

生物质等绿色资源的高效转化利用是催化科学的重要发展方向.锡硅分子筛因具有优良的催化性能而得到相关研究者的普遍关注.准确构建催化剂活性中心结构/酸性与催化反应性能之间的构效关系是新型高效催化剂设计与研发的基础.固体核磁共振（NMR）是研究分子筛活性中心局域结构、酸特性与催化反应机理的重要手段.本文简述了近年来固体NMR技术在锡硅分子筛研究领域的一系列主要进展,并进行了展望.     

泵浦光激发下金刚石纳米柱内部光场的研究

金刚石纳米柱是实现色心单光子源增强的有效结构,而纳米柱结构尺寸决定泵浦光对色心的激发强度.本文为提高其激发效率,采用时域有限差分法(Finite Difference Time Domain, FDTD)研究金刚石纳米柱的光学性质.通过仿真分析了纳米柱直径和高度对内部电场强度的影响.结果表明,在泵浦光波长为532 nm时,纳米柱内部中轴线上场强受尺寸变化影响较大,当直径不变、改变高度时,场强最大值随高度周期性变化,周期约为150 nm;当高度不变、改变直径时,场强最大值也随直径周期性变化,周期约为150 nm.通过研究不同波长的泵浦光对金刚石纳米柱内部中轴线上电场分布的影响发现,不同波长的泵浦光对纳米柱内部中轴线上最强场强对应的纳米柱尺寸有较大影响,但对于纳米柱最大场强随纳米柱尺寸变化的趋势几乎没有影响.本文通过研究上述内容,较为全面地掌握了纳米柱尺寸及泵浦光对纳米柱内部电场强度的影响规律,找到了纳米柱内部中轴线上最强场强位置,确定了激发色心的效率最高值所在位置,为金刚石纳米柱单光子源的制备提供理论指导.     

Improvement on the manipulation of a single nitrogen-vacancy spin and microwave photon at single-quantum level

It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV) spin at the single-quantum level with a microwave(MW) cavity. As an alternative, a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is proposed. According to the general mechanical parametric amplification of this in-between phonon mode, the direct spin–phonon and photon–phonon couplings are both exponentially enhanced, which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher efficiency. In view of this triple system with enhanced couplings and the additional sideband adjustable designs, this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin coherently. It is also hoped to evoke wider applications in the areas of quantum state transfer and preparation,ultrasensitive detection and quantum nondestructive measurement, etc.     

On the two methods of kinetic theory of ECRM

The kinetic theory based on the expansion of local field in the guiding center coordinate system, presented by paper[1]–[3], has successfully developed into a theoretical system. The mathematical background and physical explanation of setting up the guiding center coordinate system is expounded in the paper. By using the methods of the guiding center and waveguide coordinate systems respectively, the same dispersion equations for interaction of an axially symmetrical single momentum electron beam with TE_mn field in the circular waveguide are rigorously derived. A number of mistakes in paper[4] are indicated as well.     

The defocusing mechanism of isochronous resonances

We present a numerical study concerning the defocusing mechanism of isochronous resonance island chains in the presence of two permanent robust tori. The process is initialized and concluded through bifurcations of fixed points located on the robust tori. Our approach is based on a Hamiltonian system derived from the resonant normal form. Choosing a convenient parameter in this system, we are able to depict a comprehensive analysis of the dynamics of the problem.     

提高多光源汇聚光斑中心定位精度的形态学滤波方法

在激光指令传输中,为形成较大的光覆盖区域并增大光源的作用距离,将多个特性相同的激光器矩阵排列,构成组合光源。针对点阵多激光管光源在开放环境下成像光斑具有多个光能中心的特点,采用形态学滤波中的开启、闭合运算,去除背景噪声斑点,平滑光斑内部的小光斑叠加和干涉造成的不规则条、孔,使得能以简化的分割和定位算法,快速获得接近实际的完整光斑边界,光斑中心定位精度的均方差不大于1.2%。该方法能快速、高精度定位这种叠加光斑的中心,为远距离激光对准和测控提供了可靠的精度和时效保证。     

虚拟数据中心的功率有效嵌入算法(英文)

针对虚拟化技术中,数据中心能源消耗问题,本文研究功率有效的虚拟数据中心嵌入算法.该算法由功率感知嵌入算法、准入策略算法和碎片整理算法三部分组成.在树形网络拓扑结构中,提出功率感知的嵌入算法,得到虚拟数据中心的最低功耗嵌入方式;在动态虚拟网络业务环境中,一般嵌入算法会造成功率波动,通过业务接入策略减少功率波动;随着业务动态地进入和离开,物理网络中出现计算资源碎片,提出碎片整理算法,通过虚拟机迁移的方法,提高服务器的利用率.仿真和评估证明:随着时间的推移,算法能减少功率开支并有效降低功率波动.     

Limit Cycles Bifurcating from a k-dimensional Isochronous Center Contained in ?n with k ? n

The goal of this paper is double. First, we illustrate a method for studying the bifurcation of limit cycles from the continuum periodic orbits of a k-dimensional isochronous center contained in ℝ ⁿ with n ⩾ k, when we perturb it in a class of differential systems. The method is based in the averaging theory. Second, we consider a particular polynomial differential system in the plane having a center and a non-rational first integral. Then we study the bifurcation of limit cycles from the periodic orbits of this center when we perturb it in the class of all polynomial differential systems of a given degree. As far as we know this is one of the first examples that this study can be made for a polynomial differential system having a center and a non-rational first integral. The first and third authors are partially supported by a MCYT/FEDER grant MTM2005-06098-C01, and by a CIRIT grant number 2005SGR-00550. The second author is partially supported by a FAPESP–BRAZIL grant 10246-2. The first two authors are also supported by the joint project CAPES–MECD grant HBP2003-0017.     

有重弹性体形变与质量分布规律的简明推导

依据胡克定律与串联弹性体的劲度系数计算公式,直观简便地导出了弹性体在重力场中的形变规律、质量分布规律及其质心位置.