DECAY RATES OF PLANAR VISCOUS RAREFACTION WAVE FOR MULTI-DIMENSIONAL SCALAR CONSERVATION LAW WITH DEGENERATE VISCOSITY ON HALF SPACE

We investigate the decay rates of the planar viscous rarefaction wave of the initial-boundary value problem to scalar conservation law with degenerate viscosity in several dimensions on the half-line space, where the corresponding one-dimensional problem admits the rarefaction wave as an asymptotic state. The analysis is based on the standard L2-energy method and L1-estimate.     

Rotational analysis and line intensities of the HCO ~2A′-~2A′3_1~1 band at 296 K

This paper computes the rotational energy levels of the HCO  2A′- 2A′ transition, especially, the higher values of the rotational quantum numbers NKaKc and Ka, with the rotational constants which are obtained via B3LYP method with 6-311G basis set, and the results show that the calculated frequencies using the computed vibration-rotation energy levels are in reasonable agreement with the data from the experiment. Meanwhile, the line intensities of HCO are first reported, the results are of significance for the studying HCO.     

CH4或CH4+Ar介质阻挡放电中的离子能量和类金刚石膜制备

实验上，利用纯CH₄及CH₄+Ar在几百帕量级气压下的介质阻挡放电 制备类金刚石膜，研究了气压p与放电间隙d乘积(pd值)以及Ar的体积百分比R_Ar 对膜硬度的影响.理论上，从离子与气体分子的双体碰撞出发，利用较高折合电场强度E/n( 电场强度与粒子数密度之比)下离子及中性粒子速度分布的双温模型、离子在其他气体中运 动时遵守的朗之万方程及离子在混合气体中运动时遵守的布兰克法则，对CH⁺4和Ar⁺离子能量进行了分析.结果表明：1)CH₄介质阻挡 放电中，pd值由1.862×10³Pa mm降低至2.66×10²Pa mm时，CH+₄能量由5.4eV增加到163eV，类金刚石膜硬度由2.1GPa提高到17.6GPa ; 2) 保持总气压p=100Pa,放电间距d=5mm不变，在CH₄中加入Ar气，当R_Ar 由20％增加至83%时，CH⁺₄的能量由69eV增加到92eV,而Ar＋能量由93eV降低至72eV.虽然CH⁺₄能量增加有助于提高 沉积膜硬度，但当R_Ar大于67%，高强度Ar⁺轰击会导致膜表面石墨 化，膜硬度降低.为了验证离子能量理论模型的正确性，实验测量了H₂介质阻挡 放电中离子能量，测量结果与理论计算之间最大相对误差为16%. 关键词： 离子能量 介质阻挡放电 类金刚石膜     

Negative Dispersion of Lattice Waves in a Two—Dimensional Yukawa System

Collective motion modes existing in a two-dimensional Yukawa system are investigated by molecular dynamics simulation.The dispersion relations of transverse and longitudinal lattice waves obtained for hexagonal lattice are in agreement with the theoretical results.The negative dispersion of the parallel longitudinal wave is demonstrated by the simulation,and is explained by a physical model.     

Modified H-R mixed variational principle for magnetoelectroelastic bodies and state-vector equation

Based upon the Hellinger-Reissner (H-R) mixed variational principle for three-dimensional elastic bodies, the modified H-R mixed variational theorem for magnetoelectroelastic bodies was established. The state-vector equation of magnetoelectroelastic plates was derived from the proposed theorem by performing the variational operations. To lay a theoretical basis of the semi-analytical solution applied with the magnetoelectroelastic plates, the state-vector equation for the discrete element in plane was proposed through the use of the proposed principle. Finally, it is pointed out that the modified H-R mixed variational principle for pure elastic, single piezoelectric or single piezomagnetic bodies are the special cases of the present variational theorem.     

基于苯腙类衍生物的阴离子光学传感器的研究

本文设计合成了一种简单的比色阴离子受体1,5,5'-亚甲基双水杨醛-2,4-二硝基苯腙。利用UV-vis光谱和荧光光谱研究了受体1与阴离子AcO-,H2PO4-,F-,Cl-,Br-和I-的相互作用。当加入AcO-,F-和H2PO4-时,受体分子的吸收光谱发生明显的红移,与此同时溶液颜色由浅黄色变为红色,而加入其他阴离子则无变化。最后通过1HNMR滴定进一步研究了1与阴离子AcO-的相互作用的本质。     

从量子点的角度审视碳点的研究进展

碳点不仅具有类似于传统量子点的强发光和小尺寸特性,还表现出传统量子点无法比拟的水相分散性和生物相容性等优势.作为量子点领域的一个新兴分支,碳点的结构、合成化学和光电性质与传统量子点显著不同,也为量子点的发展提供了新的机遇和挑战.随着碳点领域的迅速发展和不断深化,越来越有必要在一些基本概念上与传统量子点比较,并从传统量子点的角度澄清碳点的独特特征和关键挑战.本综述主要聚焦于基本结构、合成化学、光学性质和应用研究等四个方面,从传统量子点基础概念的角度来重新审视碳点领域的研究进展和挑战.     

Effect of the number of defect particles on the structure and dispersion relation of a two-dimensional dust lattice system

The effect of the number of defect particles on the structure and dispersion relations of a two-dimensional (2D) dust lattice is studied by molecular dynamics (MD) simulation. The dust lattice structures are characterized by particle distribution, nearest neighbor configuration and pair correlation function. The current autocorrelation function, the dispersion relation and sound speed are used to represent the wave properties. The wave propagation of the dust lattice closely relates to the lattice structure. It shows that the number of defect particles can affect the dust lattice local structure and then affect the dispersion relations of waves propagating in it. The presence of defect particles has a greater effect on the transverse waves than on the longitudinal waves of the dust lattice. The appropriate number of defect particles can weaken the anisotropy property of the lattice.     

A Tentative Nonlinear Model for Explanation of a Perceptual Alternation Phenomenon

We present a simple three-neuron Hopfield neural network as a tentative model to illustrate the perspective alternation of Necker cube. This neural network has a chaotic attractor with two "leaves", each leaf can be regarded as a dynamic process corresponding a feature of the Necker cube. This tentative model suggests another manifestation of the role of chaos in information processing.     

静电纺丝纳米ZrO_2:Ti纤维的制备与发光性质的研究

通过静电纺丝和高温煅烧相结合的方法制备了一维钛掺杂氧化锆的纳米纤维。复合纤维在1 000℃煅烧后,由于模板剂、聚乙烯吡咯烷酮(PVP)在高温下的分解,纤维直径大大减小,扫描电镜观察最终得到直径100 nm左右的单斜相纤维。利用稳态光谱和时间分辨光谱技术室温下研究了纤维的光致发光性质。结果表明发射主峰在467 nm的宽带,在350 nm处有一个小肩峰。两种不同的发光行为可以通过ZrO2∶Ti纳米纤维中存在的两种情况的氧空穴作为电子俘获中心来解释。一种由电荷补偿产生的氧空位,俘获电子,产生467 nm处Ti参与的发光现象。另外一种ZrO2表面缺陷导致的氧空穴,对应于350 nm的发光现象,没有发现长余辉现象。测得的激发态寿命短于体材料而长于普通的纳米晶,可能是由于一维纳米结构的独特性质导致的。