压缩真空态与两原子相互作用过程中场的压缩性质

本文研究了两个二能级原子通过双光子跃迁与压缩真空态相互作用过程中辐射场的压缩和振幅平方压缩效应,讨论了两个二能级原子与光场的耦合常数的相对大小对它们的影响。     

Squeezing Properties of the Generalized Multimode Squeezed States

By means of the invariance of Weyl ordering under similar transformations we derive the explicit form of the generalized multimode squeezed states.Moreover,the completeness relation and the squeezing properties of the generalized multimode squeezed states are discussed.     

虚光子过程对光场压缩效应的影响

本文利用非相对论量子电动力学理论,研究了双光子Jaynes-Cummings模型中非旋波项对光场压缩效应的影响,证明了光场压缩效应因虚光场效应而增强,并分析了压缩程度与光场的频率、强度及光场-原子耦合常数的关系。 关键词：     

双模压缩数态及参量放大器中的压缩对称性

得到了参量放大器哈密顿量与广义双模压缩算符共同本征的双模压缩数态。提出了压缩荷与压缩对称性的概念来解释哈密顿量在由广义压缩算符生成的一维么正群变换下的不变性。     

一种船舶雷达导航回波数据压缩算法的设计

为了解决船舶雷达导航系统存储空间小、原始回波数据量多和文件大等矛盾,根据船舶雷达数据的特点,设计了位图压缩—半字节压缩—双哈夫曼压缩的混合压缩算法;该算法以半字节压缩算法为核心,融合了位图压缩算法和哈夫曼压缩算法,单纯的半字节压缩算法理论上压缩比可达到50%,将位图压缩和哈夫曼压缩与其融合后,总压缩比可达76%以上;实验证明,新算法可以为船舶导航系统节省了大量的存储资源,并提高了数据传输的速率。     

三能级原子系统中原子偶极压缩和光场压缩间的关联

通过考察三能级原子与单模和双模场相互作用系统中原子偶极压缩和光场压缩随时间的演化规律, 研究了原子偶极压缩与光场压缩之间的关系, 讨论了原子偶极压缩与光场压缩之间相互转换的特征, 并给出了初始处于偶极压缩状态的原子辐射压缩光的条件。     

压缩粒子数态中振幅k次幂的压缩效应

研究了在压缩粒子数态（ＳＮＳ）中振幅ｋ次幂的压缩效应（ＡＫＰＳ），导出有关压缩效应的普遍性公式，并用数值计算的方法，得到了前四次幂ｋ＝１，２，３和４的有关压缩特性，结果表明：这种压缩特性在光学通信领域有着一定的应用前景。 关键词：     

迭加态与压缩效应增强

本文运用量子力学态迭加原理,讨论由真空态和压缩态的迭加态获取更深压缩光场的可能性。结果表明,对弱场强浅压缩光场压缩加强效应非常显著;并且在迭加态中还呈现出反聚束的非经典效应。 关键词：     

压缩相干态通过参量图像放大系统的光学像

取压缩相干态作为参量图像放大系统的输入像，研究了输出光学像的性质.结果表明：参量 图像放大系统能够控制输出光学像的压缩度和压缩方向，即压缩度的增加与减小和压缩方向 的改变决定于参量图像放大系统的参数选择. 关键词： 参量图像放大系统 压缩相干态 压缩度 压缩方向角     

基于Matlab分析负荷对多联机IPLV的影响

多联机有其特殊的优点,但是不同部分负荷的组合对IPLV的影响仍需进一步研究。文中建立IPLV与部分负荷的相关公式,运用MATLAB软件分析不同卸载级负荷与IPLV的关系,从而确定不同部分负荷的最优组合。     

Point defects on graphene on metals

Understanding the coupling of graphene with its local environment is critical to be able to integrate it in tomorrow's electronic devices. Here we show how the presence of a metallic substrate affects the properties of an atomically tailored graphene layer. We have deliberately introduced single carbon vacancies on a graphene monolayer grown on a Pt(111) surface and investigated its impact in the electronic, structural, and magnetic properties of the graphene layer. Our low temperature scanning tunneling microscopy studies, complemented by density functional theory, show the existence of a broad electronic resonance above the Fermi energy associated with the vacancies. Vacancy sites become reactive leading to an increase of the coupling between the graphene layer and the metal substrate at these points; this gives rise to a rapid decay of the localized state and the quenching of the magnetic moment associated with carbon vacancies in freestanding graphene layers.     

Remarks on KdV-type flows on star-shaped curves

We study the relation between the centro-affine geometry of star-shaped planar curves and the projective geometry of parametrized maps into RP¹. We show that projectivization induces a map between differential invariants and a bi-Poisson map between Hamiltonian structures. We also show that a Hamiltonian evolution equation for closed star-shaped planar curves, discovered by Pinkall, has the Schwarzian KdV equation as its projectivization. (For both flows, the curvature evolves by the KdV equation.) Using algebro-geometric methods and the relation of group-based moving frames to AKNS-type representations, we construct examples of closed solutions of Pinkall’s flow associated with periodic finite-gap KdV potentials.     

五边形石墨烯负载Pt单原子稳定性能的应变调控

基于密度泛函理论的第一性原理计算方法,研究了Pt原子在五边形石墨烯(PG)上的吸附与动力学行为.研究结果表明,单个Pt原子在PG上虽然具有较大的吸附能及较高的扩散势垒,却不能够在衬底形成均匀分散的单原子.这是因为,随Pt原子数增加,Pt_n(n=1, 2, 3)在PG上的平均结合能也逐渐增加,更倾向于形成团簇,该发现有效否定了之前的报道称Pt能在PG上形成稳定的单原子催化剂这一结论(Phys. Chem. Chem. Phys. 21, 12201 (2019)).基于此,我们考虑对PG施加双轴应变,随着拉伸应力增加,Pt金属原子间的平均结合能逐渐降低,当拉伸应变施加至12%左右时,单个Pt在衬底上的结合能与Pt₂在衬底上的平均结合能相等,从而实现PG上均匀分散的Pt单原子催化剂.该结果对五边形石墨烯基材料应变调控实现单原子催化剂提供理论借鉴.     

基于F-P腔标准具的色散补偿器件的研究

介绍了标准具的结构,分析了基于标准具补偿色散的原理,讨论了该方案在光纤通信系统中的应用前景。     

Strangeness production on the nucleon and on nuclei

The coupled-channel Giessen Model is used to investigate meson production on the nucleon simultaneously in reactions with hadrons and the photon. The essential aspects of the model are discussed. Results for strangeness producing KΛ reactions on the proton and eta photoproduction on the proton and the neutron, respectively, are presented. A resonance model is used to explore the production of hypernuclei in proton and photon induced reactions.     

A note on recurrent random walks on graphs

We consider random walks on polynomially growing graphs for which the resistances are also polynomially growing. In this setting we can show the same relation that was found earlier but that needed more complex conditions. The diffusion speed is determined by the geometric and resistance properties of the graph.     

基于多处理器的视频跟踪系统研究

传统视频跟踪系统的目标检测环节常采用手动指定或使用单处理器运算来确定跟踪目标,这种方法耗费人力且检测速度慢。针对此问题提出了一种改进的图像分割方法,该方法采用多处理器系统构架,并行处理分割区域,增加了检测目标的速度,并且在后续目标跟踪环节中,各处理器根据任务划分,协同处理跟踪任务。实验结果表明基于多处理器系统构架的视频跟踪系统能够实现快速自动检测与跟踪目标,系统加速比为2．066,处理器效率为51．65％。