关于完备Riemann流形的本性谱

本文证明一类具非负截曲率完备Riemann流形的Laplace算子的本性谱为(0,+∞)。     

关于有界域的逆紧映照

本文对近20年来多复变函数的一个发展迅速的数学热门分支－逆紧映照作了一个回顾和整理。这是作者继续从事此方向研究的先声，也希望本文能为有志于此的研究者提供一些便利。本文从经典的结果开始，通过对逆紧映照在边界上的开拓及分支点的分布的讨论，详细地阐述了这些年来关于逆紧映照何时成为双全纯映照的若干结果。最后，对近年来关于逆紧映照另外的一些工作进行了简单的介绍。     

UNIQUENESS PROBLEM WITH TRUNCATED MULTIPLICITIES OF MEROMORPHIC MAPPINGS FOR MOVING TARGETS

In this article,two uniqueness theorems of meromorphic mappings on moving targets with truncated multiplicities are proved.     

Electro-Magnetic Control of Vortex Shedding Behind a Circular Cylinder

Both open- and closed-loop control algorithms have been developed for suppressing of vortex shedding behind a circular cylinder in an electrically low-conducting fluid. For the open-loop control, the localized Lorentz forces are generated parallel to the cylinder surface, which have the accelerated effect to the fluid. Furthermore, two closed-loop control methods have been derived from the equations of motion capable of determining at all times the intensity of the Lorentz force to control the vortex shedding of a cylinder.     

燃烧管内悬浮铝粉燃烧爆炸过程的研究

 铝粉的燃烧与加速机理一直是相关部门研究的热点。为了深入研究其在受限空间内的燃烧与传播特性,基于双流体模型、湍流k-ε模型以及铝粉燃烧等模型,选用SIMPLE格式,对大型卧式燃烧管内铝粉颗粒与空气的两相悬浮流湍流燃烧加速转爆炸现象进行了数值研究,得到了铝粉火焰在管内的燃烧传播过程中管内各相关参数的详细变化情况,并与相关的实验结果吻合。     

PMMA纳米球的制备及其银膜包覆技术

采用无皂乳液聚合法制备了单分散、直径为170 nm左右的聚甲基丙烯酸甲酯(PMMA)纳米球, 然后利用3-甲基丙烯酰氧基丙基三甲氧基硅烷(MATS)和3-巯丙基三甲氧基硅烷(MPTMS)对PMMA纳米球进行表面改性, 在其表面包覆一层均匀的巯基, 通过巯基与银离子之间的相互作用, 使银在PMMA纳米球表面成核长大, 从而合成PMMA/Ag纳米球壳粒子. 通过扫描电子显微镜、投射电子显微镜和紫外-可见吸收光谱测试技术对产物性能进行了表征, 研究结果表明, 制备的PMMA/Ag纳米球壳粒子的分散性好、包覆均匀.     

Discrete Boltzmann Method with Maxwell-Type Boundary Condition for Slip Flow

The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model(DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation.It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model.Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model.To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified.     

Teleportation of an arbitrary mixture of diagonal states of multiqudit

This paper proposes a scheme to teleport an arbitrary mixture of diagonal states of multiqutrit via classical correlation and classical communication. To teleport an arbitrary mixture of diagonal states of N qutrits, N classically correlated pairs of two qutrits are used as channel. The sender （Alice） makes Fourier transform and conditional gate （i.e., XOR（3） gate） on her qutrits and does measurement in appropriate computation bases. Then she sends N ctrits to the receiver （Bob）. Based on the received information, Bob performs the corresponding unitary transformation on his qutrits and obtains the teleported state. Teleportation of an arbitrary mixture of diagonal states of multiqudit is also discussed.     

翼型绕流电磁控制的实验和数值研究

分布在弱电介质溶液中的电磁力(Lorentz力)，可以有效地控制边界层的流动.利用以转动水槽为主的实验系统和基于双时间步Roe格式的数值方法，对翼型绕流的电磁控制进行了实验和数值研究.结果表明，对于一定攻角的翼型，电磁力可以控制其绕流形态.当电磁力方向与流动方向相同时，可以抑制分离，消除涡街，其效果与减小攻角类似.当电磁力的方向与流动方向相反时，可在流场中形成大涡组成的涡街，增强流体的混合能力，其效果与增大攻角类似.     

Scheme for implementing quantum secret sharing via cavity QED

An experimentally feasible scheme for implementing quantum secret sharing via cavity quantum electrodynamics （QED） is proposed. The scheme requires the large detuning of the cavity field from the atomic transition, the cavity is only virtually excited, thus the requirement on the quality factor of the cavity is greatly loosened.