外加磁场微波等离子体喷流对平面电磁波衰减的实验研究

采用空间透射波测量方法,实验研究透波密闭石英玻璃容器内等离子体喷流对垂直和水平极化电磁波的衰减,在有和无外加磁场条件下分析实验参数对等离子吸波效应的影响,分析等离子体的吸波机理.实验结果表明在非磁和本实验条件下,平面电磁波在等离子体中的衰减机理为碰撞吸收;在有磁和本实验条件下,平面电磁波在磁等离子体中的衰减机理同样为碰撞吸收,但是外加磁场的存在有限地改善了等离子体的吸波效应.为了使磁等离子体最有效地吸收电磁波,应该提高磁场感应强度,把高频混杂频率提高到测试微波频率范围内,或降低微波测试频率至本实验中的高混 关键词： 等离子体相互作用 电磁波 电磁波在等离子体中的传输     

A comment on “Optimizing an objective function under a bivariate probability model”

This note provides simpler, shorter and more general formulas of the product moments considered by Brusset and Temme [Brusset, X., Temme, N.M., 2007. Optimizing an objective function under a bivariate probability model. European Journal of Operational Research 179, 444–458].     

Convex and star-shaped sets associated with multivariate stable distributions, I: Moments and densities

It is known that each symmetric stable distribution in is related to a norm on that makes embeddable in L_p([0,1]). In the case of a multivariate Cauchy distribution the unit ball in this norm is the polar set to a convex set in called a zonoid. This work interprets symmetric stable laws using convex or star-shaped sets and exploits recent advances in convex geometry in order to come up with new probabilistic results for multivariate symmetric stable distributions. In particular, it provides expressions for moments of the Euclidean norm of a stable vector, mixed moments and various integrals of the density function. It is shown how to use geometric inequalities in order to bound important parameters of stable laws. Furthermore, covariation, regression and orthogonality concepts for stable laws acquire geometric interpretations.     

A unified theory for turbulent wake flows described by eddy viscosity

In this paper, we consider the conservation laws for the far downstream wake equations described by eddy viscosity. A basis of conserved vectors is constructed. The well-known conserved quantities for the turbulent classical wake and the turbulent wake of a self-propelled body are obtained by integrating the corresponding conservation law across the wake and imposing the boundary conditions. For the wake of a self-propelled body the additional condition that the drag on the body is zero and is required to obtain the conserved quantity. A third conservation law, which possibly belongs to another type of wake, is discovered. The Lie point symmetry associated with the conserved vector is used to obtain the invariant solution and a typical velocity profile for this wake is provided. This wake appears to have common properties with the other two well-known wakes. We then analyse the invariant solutions to all three wake problems and prove that a simple mathematical relationship exists between them thus unifying the theory for turbulent wake flows.     

脉搏波系统的力学模型及反演兼对若干中医学问题的讨论

对脉搏波进行客观化定量研究,是我们面临的跨中医与西医、跨医学与数理学科的新挑战,是中国传统医学现代化发展的重点研究课题之一.本文遵循中医整体观点的传统思路,把脉搏波系统理解为生命能量以波的形式在血液中传播的整个系统,从连续介质力学的波动理论出发,为脉搏波系统建立一个等价的力学模型,并把力学反演方法推广发展到脉搏波.指出脉搏波是压力波P（X,t）,质点速度波v（X,t）、比容波V（X,t）和内能波E（X,t）这些不同形式波动的总成.脉搏现象包含着血液的流动和在血液中以远快于血液流速之波速传播的携带能量的脉搏波.前者是人眼易见的实体血液的“物质流”,而后者是人眼不易见、以波的形式传播的“能量流”,可分别理解为中医的“血”和“气”.脉搏波的传播特性由反映生命体整体系统的本构方程决定,就其重要性和地位而言,系统本构方程与中医的体质相当,应探索其内在联系.初步讨论了脉搏波系统本构关系非线性效应和黏性效应对脉搏波特性的影响.      

柔性可穿戴电子传感器研究进展

随着智能终端的普及,可穿戴电子设备呈现出巨大的市场前景.传感器作为核心部件之一,将影响可穿戴设备的功能设计与未来发展.柔性可穿戴电子传感器具有轻薄便携、电学性能优异和集成度高等特点,使其成为最受关注的电学传感器之一.综述了近年来柔性可穿戴电子传感器的研究进展,包括压阻、电容、压电、力致发光和摩擦电等信号转换机理,金属、无机半导体、有机和碳材料等柔性可穿戴电子的常用材料,柔性电子传感器的印刷制造及其在体温和脉搏检测、表情识别和运动监测等方面的最新应用,最后提出了柔性可穿戴电子传感器面临的挑战与未来发展方向.     

Cs(6 ~2D_(5/2))与H_2反应生成的CsH分子的转动和振动态分布

利用激光泵浦-探测技术,在样品池条件下,研究了Cs(6D5/2)态与H2反应生成的CsH分子基电子态的转动和振动的量子态分布。在Cs-H2混合蒸气中,脉冲激光双光子激发Cs(6D5/2)态,另一台调频脉冲激光器扫描CsHX1Σ+(v″,J″)→A1Σ+(v′,J′=J″±1)吸收线,发现CsH分子只有v″=0和1上的振动带上有布居而不布居在v″1的振动带上。v″=0和1上的转动带分布呈现单峰结构,其峰值位于J″=6～8处,转动带分布轮廓与池温下的统计分布接近。转动Boltzmann温度分别为(458±20)K(对v″=1)和(447±18)K(对v″=0),得到的CsH分子的转动温度稍低于池温。从转动态分布得到v″=1与v″=0上布居数之比约为0.897,从而计算出CsH基电子态上的平均转动能ER和平均振动能EV,有效能减去平均振转能得到平均平动能ET。CsH分子3种能量的相对比值fT∶fV∶