约束系统量子化中Dirac方法与Faddeev-Jackiw方法的等价性

对约束系统量子化中Dirac方法和 Faddeev-Jackiw方法进行了讨论，并对它们的运动方程、正则量子化的等价性进行证明.找出了两种方法中约束的对应关系. 关键词： Faddeev-Jackiw方法 Dirac方法 约束系统 正则量子化     

AN EFFECTIVE APPROACH FOR TWO-DIMENSIONAL POLARONS IN AN ASYMMETRIC QUANTUM DOT

Within the framework of Feynman-Haken path integral theory, we calculate the ground-state energy of two-dimensional polarons in asymmetric quantum dots for arbitrary electron-phonon coupling constants. From a general three-dimensional Hamiltonian, some interesting problems, such as polarons in quasi-one-dimensional quantum wires and quasi-zero-dimensional asymmetric or symmetric quantum dots can be easily discussed only by taking different limit in the whole coupling regime. After the numerical calculation, we find that the relative polaronic correction increases monotonically with the decrease of effective dot size, and it becomes more pronounced with increasing dimension and asymmetry. Moreover, despite the insensitivity of relative polaronic enhancement to the variation of coupling constant at weak coupling, the correction is related to the coupling constant as the latter becomes larger.     

卡尔曼滤波紫外光度法同时测定酱油、食醋中的山梨酸和苯甲酸

在酸性条件下，采用乙酸乙酯萃取、Na2HPO4溶液反萃取分离酱汪、食醋中的山梨酸、苯甲酸，卡尔曼滤波法计算结果，并与比值导数波谱法进行比较。结果表明，卡尔曼滤波法较地数波谱法有较高准确度和精密度，并能监测干扰物质存在与否。用于实际样品分析有更高的可靠性。     

Modeling synchronization and suppression of spontaneous otoacoustic emissions using Van der Pol oscillators: effects of aspirin administration

Many of the aspects of the interaction of spontaneous otoacoustic emissions with external tones (suppression and synchronization) can be qualitatively simulated by the behavior of a single driven Van der Pol oscillator. Analytical and numerical investigations of a model of spontaneous otoacoustic emissions based on such an oscillator (with appropriate parametric changes in the nonlinear and negative damping components) lead to predictions of the nature of the changes in suppression and synchronization (frequency-locking) tuning curves when the levels of spontaneous otoacoustic emissions are modified. Observations of the suppression and synchronization of spontaneous otoacoustic emissions by external tones of different frequencies and levels were obtained while the levels of spontaneous emissions were altered by aspirin administration. Modeling an emission as a single Van der Pol oscillator qualitatively accounts for: (1) the reduction of the level of an external tone required to suppress the emission by a decibel amount equivalent to the level reduction induced by aspirin administration; (2) the broadening of the frequency-locking tuning curve of an emission whose level is reduced; and (3) the pulling of the emission frequency by an external tone. It does not account for: (1) the observed asymmetry in the slopes of the external-tone suppression curves (more gradual for frequencies of the suppressor tone higher, rather than lower, than that of the emission); and (2) the frequency pushing of the emission by an external tone.     

A functional modulus of continuity for Brownian motion

In this paper, we prove a sharpening of large deviation for increments of Brownian motion in (p,r)-capacity and Hölder norm case. As an application, we obtain a functional modulus of continuity for (p,r)-capacity in the stronger topology.     

Tunable negative refraction by electro-optical control in two-dimensional photonic crystal

This paper describes a simple hydrothermal procedure for high-yield synthesis of single-crystalline ZnO hexagonal nanoplates in a surfactant-free system at 70 °C. The structures and morphologies of the synthesized ZnO nanoplates are derived from characterisation by X-ray diffraction, and scanning and transmission electron microscopy. Their optical properties are recorded by Raman and photoluminescence spectroscopy. These ZnO hexagonal nanoplates exhibit the enhanced photocatalytic activity of phenol photodecomposition, suggesting that they could be served as an active system for the treatment of the waste water, in addition to their common applications. PACS 81.10.Dn; 61.10.Nz; 68.37.Hk; 78.55.Hx     

Formation of long range ordered arrangement of quantum dots with the help of lateral centripetal flow

A simple “chimney” method was used to eliminate the voids in an arrangement of quantum dots sized 2 nm on a solid substrate, which resulted in a large well ordered superlattice of area in the order more than 1 μm². Based on the principle of speeding up the interparticle interaction of nanoparticles to overcome the particle-substrate one, a lateral centripetal force originated from a glass tube acting as a chimney in a simple evaporation device is imposed. This method allows the packing process to be controlled in a mechanical force field, that is, with the same nanogold dispersion different patterns on a substrate—from separate dots to an ordered compact monolayer or even a multilayer structure—could be easily obtained.     

Dynamic behavior of discrete-time multiagent systems with general communication structures

In this paper, we discuss the dynamic behavior of networks of dynamic agents with general communication topologies. We first analyze the basic case: systems with communication topologies that have spanning trees, i.e., the systems that solve consensus problems. We establish an algebraic condition to characterize each agent's contributions to the final state. And we also study the influence of time-delays on each agent's contributions. Then, we investigate the general case: systems with weakly connected topologies. By using matrix theory, we prove that the states of internal agents will converge to a convex combination of boundary agents in the absence or presence of communication time-delays, and we also show that the coefficients of the convex combination are independent of time-delays even if the delays are time-varying. These results have broad applications in other areas, e.g., study of swarm behavior, formation control of vehicles, etc.     

平面研磨中影响工件起动力矩的因素

本文针对平面研磨过程中工件运动的随机性，从理论上求出了在机床起动瞬间磨具作用于工件上的合力矩；探讨了影响这个力矩的主要因素，偏心距和工件几何尺寸的作用规律；为选择研磨参数提供一理论依据。