压缩态光场平衡零拍探测的位相锁定

平衡零拍探测是测量量子光场的重要方法之一. 通过对相位灵敏光学参量放大器注入的信号进行位相调制, 然后利用平衡零拍探测系统测量光学参量放大器输出的压缩光. 将相位灵敏光学参量分别运转在参量放大和参量缩小, 通过观察噪声谱中的调制信号就可确定测量的量子光场是正交振幅或位相分量. 通过解调位相调制信号可获得误差信号, 实现锁定平衡零拍探测系统本底光与待测光场相对位相为零(对应于待测光场振幅噪声分量). 关键词： 平衡零拍探测 位相锁定     

钯催化Stille交叉偶联反应研究新进展

综述了钯催化Stille交叉偶联反应的最新研究进展, 主要包括三个方面: (1)有机锡化合物与有机亲电试剂如卤代芳香烃、卤代烷烃、酰氯等的反应; (2)Stille反应的机理; (3) Stille反应在有机合成中的应用.     

基于药效团模型从中草药数据库中搜索gpIIb/IIIa受体抑制剂

选择20 个3,4-二氢-1(1H)-异喹啉酮类gpIIb/IIIa受体抑制剂作为训练集, 利用Catalyst软件包建立了gpIIb/IIIa受体抑制剂三维药效团模型. 探讨了药效团作用模式. 并通过建立的可靠性最佳的药效团模型(线性回归系数r=0.7715), 从中草药数据库中虚拟筛选了gpIIb/IIIa受体抑制剂, 通过实验活性测定得到了8个抑制ADP活化全血血小板聚集的IC50从40到100 μmol·L-1的化合物, 进一步证明了所建药效团模型的有效性.     

Classical mechanics on noncommutative space with Lie-algebraic structure

We investigate the kinetics of a nonrelativistic particle interacting with a constant external force on a Lie-algebraic noncommutative space. The structure constants of a Lie algebra, also called noncommutative parameters, are constrained in general due to some algebraic properties, such as the antisymmetry and Jacobi identity. Through solving the constraint equations the structure constants satisfy, we obtain two new sorts of algebraic structures, each of which corresponds to one type of noncommutative spaces. Based on such types of noncommutative spaces as the starting point, we analyze the classical motion of the particle interacting with a constant external force by means of the Hamiltonian formalism on a Poisson manifold. Our results not only include that of a recent work as our special cases, but also provide new trajectories of motion governed mainly by marvelous extra forces. The extra forces with the unimaginable -, and -dependence besides with the usual t-, x-, and -dependence, originating from a variety of noncommutativity between different spatial coordinates and between spatial coordinates and momenta as well, deform greatly the particle’s ordinary trajectories we are quite familiar with on the Euclidean (commutative) space.     

玉米秸秆生物油-柴油乳化油的燃烧特性

试验用生物油是玉米秸秆快速热解液化的产物,主要成分为含氧有机混合物和水,不宜直接作为燃料使用,但与柴油乳化后可实现其在发动机中应用.在一台未作改动的直喷式柴油机上研究了玉米秸秆生物油质量分数分别为10%(B10)和20%(B20)的生物油-柴油乳化油的燃烧特性.结果表明:与0号柴油相比,乳化油的滞燃期延长,预混燃烧放热...     

生物柴油-生物油乳化油的燃烧排放特性

在一台未作改动的直喷式柴油机上研究了生物油质量分数分别为10%和20%的生物柴油生物油乳化油的燃烧与排放特性。结果表明:与生物柴油相比,燃用乳化油时燃烧始点推迟,预混燃烧放热峰值升高,扩散燃烧放热峰值、最高燃烧压力和燃烧温度降低,燃烧持续期缩短,且随着生物油含量增加以上趋势更明显。燃用含10%生物油的乳化油时燃油经济性较生物柴油略低,与0号柴油相当,而燃用含20%生物油的乳化油时燃油经济性则低于生物柴油和0号柴油。乳化油的NO_x排放明显低于生物柴油,而碳烟排放高于生物柴油,但低于0号柴油。     

基于范阿伦卫星观测的槽区嘶声波冷等离子体色散关系的适用性评估

等离子体层嘶声波对电子的散射损失是地球内外辐射带之间的槽区(1.8≤L≤3)形成的主要机制.冷等离子体色散关系被广泛地运用于量化嘶声波对高能电子的散射效应研究中,而在真实的磁层环境中,热等离子体的存在会修正嘶声波的色散特性.基于范阿伦双星的观测数据,对比了利用磁场观测数据得到的槽区嘶声波观测幅值和反演幅值,并研究了空间位置与地磁活动水平对嘶声波冷等离子体色散关系适用性的影响.结果表明,冷等离子体近似整体上高估了嘶声波的幅值,观测幅值与反演幅值的差异有着很强的日夜不对称性,而没有明显的地磁活动强度依赖性.此外发现,波动磁场的反演强度在低频(高频)处显著低于(高于)观测强度,意味着冷等离子体近似整体上高估(低估)了嘶声波对槽区较低(较高)能量电子的散射强度.研究证明,槽区嘶声波冷等离子体色散关系的适用范围有很强的空间区域与频率局限性,这对深入理解槽区电子的动态演化过程有非常重要的意义.     

Measurement of intensity difference squeezing via non-degenerate four-wave mixing process in an atomic vapor

We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light （no extra noise） for the probe beam is used.     

Controlling Factors of the Electric Field at the Triple Junction

The metal-dielectric-vacuum junction is defned as the triple junction owned enhanced electric field, thus this special region is regarded as the location where primary electrons emission is favored. For electron emission, triple junction could affect both the flashover breakdown of insulators and the electron emission property of ferroelectrie cathodes. In this study, we theoretically investigate the electric field enhancement in the triple-junction region. It is found that the key parameter to determine the field enhancement is the taper angle of the electrode and the relative permittivity of the dielectric. In addition, we first deduce the accurate expression of the electric field in this special region. The controlling parameters for determining the field enhancement are discussed in detail. We also discover the way to reduce the electric field of this region through simulation. The current analysis would be useful for both the electron emission enhancement and the issue of flashover breakdown.