Partial electrical potential distribution around nanospheres in metallic nanostructured films

In light of the nanostructured surface model, where half-spherical nanoparticles grow out symmetrically from a plane metallic film, the mathematical model for the partial electrical potential around nanospheres is developed when a uniform external electric field is applied. On the basis of these models, the three-dimensional spatial distribution of the partial electrical potential is obtained and given in the form of a curved surface using a numerical computation method. Our results show that the electrical potential distribution around the nanospheres exhibits an obvious geometrical symmetry. These results could serve as a reference for investigating many abnormal phenomena such as abnormal infrared effects, which are found when CO molecules are adsorbed on the surface of nanostructured transition metals.     

金属纳米结构表面吸附的CO分子在外电场中的相互作用

建立金属纳米颗粒在外电场中的排列结构模型，用经典理论分析纳米结构金属表面上吸附的CO分子在外电场中的相互作用能，包括有效偶极子间的相互作用和与局域电场的相互作用，并讨论和计算了纳米颗粒表面附近的局域电场. 用Monte-Carlo方法进行数值计算和模拟，具体给出纳米颗粒表面CO分子的分布和相互作用能，表明金属表面纳米结构使CO产生凝聚，并使分子相互作用能增加，为解释异常红外吸收效应提供依据. 关键词： 纳米结构金属 吸附分子 相互作用 局域电场     

Electric potential distribution near nanocone arrays on metal substrates

Based on the nanostructured surface model,where conical nanoparticle arrays grow out symmetrically from a plane metal substrate,a theoretical model of the local electric potential near nanocones is built when a uniform external electric field is applied.In terms of this model,the electric potential distribution near the nanocone arrays is obtained and given by a curved surface using a numerical computation method.The computational results show that the electric potential distribution near the nanocone arrays exhibit an obvious geometrical symmetry.These results could serve as a basis for explaining many abnormal phenomena,such as the abnormal infrared effects(AIREs) which are found on nanostructured metal surfaces,as well as a reference for investigating the applications of nanomaterials,such as nanoelectrodes and nanosensors.     

用时域有限差分法分析一氧化碳分子吸附在铂表面的CO-Pt振动光谱

根据CO分子吸附在Pt表面相互作用的类Rose势中的不同吸附能参量E0、振动参量α0和平衡间距γe,利用时域有限差分方法数值求解CO-Pt吸附体系的Schr(o)dinger方程,得到CO-Pt体系波函数的数值解.通过离散Fourier变换得到本征振动能量,并拟合成非谐性光谱项表达式.结果表明E0对CO-Pt体系的振动频率影响不大,而α0变小或γe变大时体系振动频率降低,导致谱线红移;同时表明CO-Pt体系的本征振动仍接近谐振动.     

修正振幅调制的光电混合圆谐联合变换相关器作旋转不变的目标检测

提出一种修正振幅调制的光电混合圆谐联合变换相关器作旋转不变的目标检测的实验系统。参考图像（即圆谐展开分量的实部和虚部）、圆盘状的局部偏置函数以及目标图像同时显示于输入面。此方法对联合功率谱作了修正,先将联合功率谱减去纯输入景物（含局部偏置函数）的功率谱和参考图像（含局部偏置函数）的功率谱,再加上局部偏置函数的功率谱,然后将所得修正的联合功率谱乘以振幅调制滤波函数。这种方法能产生比普通的圆谐联合变换     

Phase space reconstruction of chaotic dynamical system based on wavelet decomposition

In view of the disadvantages of the traditional phase space reconstruction method,this paper presents the method of phase space reconstruction based on the wavelet decomposition and indicates that the wavelet decomposition of chaotic dynamical system is essentially a projection of chaotic attractor on the axes of space opened by the wavelet filter vectors,which corresponds to the time-delayed embedding method of phase space reconstruction proposed by Packard and Takens.The experimental results show that,the structure of dynamical trajectory of chaotic system on the wavelet space is much similar to the original system,and the nonlinear invariants such as correlation dimension,Lyapunov exponent and Kolmogorov entropy are still reserved.It demonstrates that wavelet decomposition is effective for characterizing chaotic dynamical system.     

Local electric field and configuration of CO molecules adsorbed on a nanostructured surface with nanocones

Based on the nanostructured surface model that the(platinum,Pt) nanocones grow out symmetrically from a plane substrate,the local electric field near the conical nanoparticle surface is computed and discussed.On the basis of these results,the adsorbed CO molecules are modelled as dipoles,and three kinds of interactions,i.e.interactions between dipoles and local electric field,between dipoles and dipoles,as well as between dipoles and nanostructured substrate,are taken into account.The spatial configuration of CO molecules adsorbed on the nanocone surface is then given by Monte-Carlo simulation.Our results show that the CO molecules adsorbed on the nanocone surface cause local agglomeration under the action of an external electric field,and this agglomeration becomes more compact with decreasing conical angle,which results in a stronger interaction among molecules.These results serve as a basis for explaining abnormal phenomena such as the abnormal infrared effect(AIRE),which was found when CO molecules were adsorbed on the nanostructured transition-metal surface.     

Light-extraction efficiency and forward voltage in GaN-based light-emitting diodes with different patterns of V-shaped pits

We present a new method of making a textured V-pit surface for improving the light extraction efficiency in GaN- based light-emitting diodes and compare it with the usual low-temperature method for p-GaN V-pits. Three types of GaNbased light-emitting diodes （LEDs） with surface V-pits in different densities and regions were grown by metal-organic chemical vapor deposition. We achieved the highest output power and lowest forward voltage values with the p-InGaN V-pit LED. The V-pits enhanced the light output power values by 1.45 times the values of the conventional LED owing to an enhancement of the light scattering probability and an effective reduction of Mg-acceptor activation energy. Moreover, this new technique effectively solved the higher forward voltage problem of the usual V-pit LED.     

纳米结构Pt膜上CO吸附的异常红外效应机理研究

CO吸附在经方波电势处理后的纳米结构Pt金属膜电极上可观察到异常红外效应（AIREs）.在实验基础上用粒子间的相互作用和电子-空穴衰减机理分析、模拟了AIREs，表明Pt金属表面的纳米岛状结构增强了CO分子间及CO分子与纳米结构表面的相互作用，电子-空穴衰减引起的能量转移和粒子间相互作用的增强可以导致异常红外吸收谱线变化特征的出现. 关键词： 异常红外效应 粒子相互作用 电子-空穴衰减     

Local field distribution and configuration of CO molecules adsorbed on the nanostructure platinum surface

This paper shows that the local electric field distribution near the nanostructure metallic surface is obtained by solving the Laplace equation, and furthermore, the configuration of CO molecules adsorbed on a Pt nanoparticle surface is obtained by using Monte Carlo simulation. It is found that the uneven local electric field distribution induced by the nanostructure surface can influence the configuration of carbon monoxide (CO) molecules by a force, which drags the adsorbates to the poles of the nanoparticles. This result, together with our results obtained before, may explain the experimental results that the nanostructure metallic surface can lead to abnormal phenomena such as anti-absorption infrared effects.