Vanishing Viscosity Limit of the Compressible Navier–Stokes Equations for Solutions to a Riemann Problem

We study the vanishing viscosity limit of the compressible Navier–Stokes equations to the Riemann solution of the Euler equations that consists of the superposition of a shock wave and a rarefaction wave. In particular, it is shown that there exists a family of smooth solutions to the compressible Navier–Stokes equations that converges to the Riemann solution away from the initial and shock layers at a rate in terms of the viscosity and the heat conductivity coefficients. This gives the first mathematical justification of this limit for the Navier–Stokes equations to the Riemann solution that contains these two typical nonlinear hyperbolic waves.     

具预警功能的三部件并联可修复系统的可靠性分析

研究了具有预警功能的三部件并联且有两个热备器的可修复系统,系统可转化为一个Banch空间上的抽象Cauchy问题.首先利用半群理论证明了该系统强解的存在唯一性,其次运用了代数方法证明了0是系统算子的简单本征值,最后对系统和不含预警功能的系统的可用度进行了比较分析.     

具有剩余寿命且排队空间有限的M/G/1排队模型非负解的存在唯一性

研究了以剩余寿命作为增补变量,排队空间有限的M/G/1排队模型,利用泛函分析中线性算子半群的积分半群理论讨论了该模型的瞬态解的存在唯一性问题。     

Optical multi-image encryption based on frequency shift

We present a novel multi-image encryption and decryption algorithm based on Fourier transform and fractional Fourier transforms. Lower frequency parts of the original images are selected, frequency shifted and encrypted by using double phase encoding in fractional Fourier domains. Multiple images are encrypted together into a single one. A simple optical setup is given to implement the proposed algorithm. This scheme has features of enhancement in decryption accuracy and high optical efficiency. Numerical results have been given to verify the validity and efficiency of the proposed scheme.     

Facile synthesis of SERS active Ag nanoparticles in the presence of tri-n-octylphosphine sulfide

A facile and novel way was reported here for the synthesis of hydrophobic Ag nanoparticles (NPs), using AgNO₃, tri-n-octylphosphine (TOP) and sulfur (S) powder in process. TOP was used as solvent, reducing agent and stabilizer. S could chelate with excessive TOP to form trioctylphosphine sulfide (TOPS), which served as second capping agent. The hydrophobic Ag NPs could be transformed into hydrophilic state through ligand exchange. Furthermore, surface-enhanced Raman scattering (SERS) spectra of 4-aminothiophenol (4-ATP) were obtained on the hydrophobic and hydrophilic Ag NPs modified substrates, indicating that the as-synthesized Ag NPs had great potential for high sensitive optical detection applications.     

具有预警功能的可修复系统

研究了一个具有预警功能的可修复系统．通过选取空间和定义系统算子，将模型方程转化成为了抽象Cauchy问题．然后利用算子半群理论证明了系统解的存在唯一性与指数稳定性．另外，当风险系数趋于无穷时，这种系统逼近于一种具有弱解的模型系统，利用这个性质可得出相应结论并给出了数值仿真例子．     

基于辩论的多agent商务谈判辩论产生和决策过程研究

由于在自动谈判中加入辩论成分能够允许Agent在谈判过程中通过辩论的形式交换和交流额外的信息,进而影响对方的信念、偏好、意向或目标,使谈判向着有利于达成协议方向发展,并提高谈判效率,降低交易成本,因此已经成为多Agent商务谈判领域的热点发展方向.本文针对如何产生辩论这一重要问题进行研究,提出了"候选辩论集的产生策略"和"基于冲突分析的辩论目标产生模型",分析了基于辩论的多Agent商务谈判决策过程,并通过原型系统进行了验证.本文的研究成果将促使多Agent商务谈判系统向着更为实用方向发展.     

LO-phonon effect on the exciton binding energy in polar rectangular quantum wires

Longitudinal optical phonon effect on Wannier excitons in polar rectangular quantum wires is studied by a variational approach. The binding energy is calculated and the numerical results for several II-VI and III-V compound semiconductor rectangular quantum wires are given. The results show that the phonon effect reduces the binding energy and cannot be neglected. The phonon contribution to the binding energy is sensitive to the size of the rectangular quantum wire section, and increases with decreasing section area. The results for the GaAs rectangular quantum wires coincide with the experimental results. The calculated binding energy and the phonon effect in II-VI QWWs are both stronger than those in III-V compound systems, and the results for ZnSe QWW are qualitatively in agreement with the experiments.     

大气气溶胶中溴、碘总量及其形态的提取和测定

比较了超声纯水提取不同时间和多种密封提取条件下大气气溶胶样品滤膜中溴、碘形态稳定性和提取率。结果表明:密封提取方法的提取率高于超声提取方法,但有可能破坏了某种未知的有机碘形态;在长时间纯水超声条件下,醋酸纤维(CF)空白滤膜加标回收中I-形态不稳定。因此,纯水超声提取5 min为最佳提取条件。对比醋酸纤维(CF)和玻璃纤维(GF)空白滤膜加标回收实验发现,各种提取条件下GF材质对样品中溴、碘形态稳定性的干扰比CF材质小。在优化大气气溶胶溴、碘形态提取方法的基础上,建立了HPLC-ICP-MS测定大气气溶胶中BrO3-、Br-、IO3-和I-的方法,并对合肥地区气溶胶样品中溴、碘总量及形态进行测定。合肥地区气溶胶中溴和碘总量浓度分别为883和231 pmol/m3。其中,Br-占总溴的69%,BrO3-未检出;70%的碘为未知形态,包括可溶性有机碘和不可溶性碘。     

罗丹明类光学传感器在金属离子细胞成像中的应用

由于优良的光学性能和较宽的pH值适用范围,罗丹明类物质已经被广泛选作重金属与过渡金属离子细胞成像光学传感器的光学母体.对近年来罗丹明类光学传感器在重金属与过渡金属离子细胞成像中的应用进行了详细综述,包括设计思路、作用机理、应用范围等都进行了详细的比较分析.另外,提出了罗丹明类重金属和过渡金属细胞成像光学传感器目前存在的问题和今后的发展趋势.