溶剂对香豆素343染料光谱性质和最低激发态偶极矩的影响

通过对香豆素343(C343)在不同溶剂中的稳态吸收光谱、稳态荧光光谱和时间分辨荧光光谱的分析,研究了溶剂对C343的光谱性质的影响,并获得了光谱特性与溶剂极性之间的依赖关系. 吸收光谱峰值的红移随着溶剂极性的增加而发生较小的变化. 然而,荧光光谱的峰值对溶剂的极性却很敏感,并随着溶剂极性参数f(ε,n)的增加呈线性增长. 这是由于C343激发态电荷分布的变化导致了它在极性溶剂中第一激发单重态能级的变化. 用溶剂效应测量法和量子化学计算方法确定了C343最低激发态的偶极矩,这两方法所得的结果一致. C343在不同溶剂中的时间分辨荧光光谱研究表明荧光寿命随着溶剂极性的增加而增加,即从甲苯溶液的3.09 ns线性地增加到水溶液中4.45 ns;荧光寿命延长的根源可归因于C343与氢键给体溶剂之间的分子间氢键相互作用.     

Study on the Range of Particles Size Measured by Backscattering Method in Visual‐infrared Incident Spectrum

For the measurement of particles size with backscattering method, the suitable range of particles size measurement have been presented by independent algorithm in Visual‐infrared incident spectrum. We defined the range according to the retrieved results based on the analysis and comparison to many kinds of R‐R distribution function. The simulation computation results showed that the particles size measurement range is from 0.05 μm to 18 μm with incident spectrum from 0.4 μm to 2 μm and different refractive index. The results retrieved were satisfied even if 1 % noise was added into the backscattering intensity.     

DFT study on electronic structure and optical properties of N-doped,S-doped,and N/S co-doped SrTiO3

The electronic structures and optical properties of N-doped, S-doped and N/S co-doped SrTiO₃ have been investigated on the basis of density functional theory (DFT) calculations. Through band structure calculation, the top of the valence band is made up of the O 2p states for the pure SrTiO₃. When N and S atoms were introduced into SrTiO₃ lattice at O site, the electronic structure analysis shows that the doping of N and S atoms could substantially lower the band gap of SrTiO₃ by the presence of an impurity state of N 2p on the upper edge of the valence band and S 2p states hybrid with O 2p states, respectively. When the N/S co-doped, the energy gap has further narrowing compared with only N or S doped SrTiO₃. The calculations of optical properties also indicate a high photo response for visible light for N/S co-doped SrTiO₃. Besides, we find a new impurity state which separates from the O 2p states could improve the photocatalytic efficiency and we also propose a model for light electron-hole transportation which can explain the experiment results well. All these conclusions are in agreement with the recent experimental results.     

Affine-periodic solutions by averaging methods

This paper concerns the existence of affine-periodic solutions for perturbed affine-periodic systems.This kind of affine-periodic solutions has the form of x(t+T)≡Qx(t) with some nonsingular matrix Q,which may be quasi-periodic when Q is an orthogonal matrix. It can be even unbounded but x(t)/|x(t)| is quasi-periodic,like a helical line. for example x(t)=e~(at)(cos ωt, sin ωt), when Q is not an orthogonal matrix. The averaging method of higher order for finding affine-periodic solutions is given by topological degree.     

Second-order Asymptotics on Distributions of Maxima of Bivariate Elliptical Arrays

Let {(ξni, ηni), 1 ≤ i ≤ n, n ≥ 1} be a triangular array of independent bivariate elliptical random vectors with the same distribution function as(S_1, ρ_n S_1 +(1-ρ_n~2S_2)~(1/2)), ρn∈(0, 1), where(S1, S2) is a bivariate spherical random vector. For the distribution function of radius (S_1~2+ S_2~2)~(1/2) belonging to the max-domain of attraction of the Weibull distribution, the limiting distribution of maximum of this triangular array is known as the convergence rate of ρn to 1 is given. In this paper,under the refinement of the rate of convergence of ρn to 1 and the second-order regular variation of the distributional tail of radius, precise second-order distributional expansions of the normalized maxima of bivariate elliptical triangular arrays are established.     

汞原子6sns 3S1,6snd 3D1 Rydberg系列的寿命

利用多通道量子数亏损理论计算了汞原子6sns^3S1(n=11～25),6snd^3D1(n=12～24)两个Rydberg系列的能级和寿命,给出了这两个系列寿命所遵循的公式,6sns^3S。系列为r=0．814v^2.835(ns),6snd^3D1系列为r=0．302v^2.926ns),其中v为有效量子数。     

Spatiotemporal propagation characteristics based on the exact solutions of the generalized nonlinear Schrödinger equation by intensity moments

Based on the exact solutions of the (3 + 1)-dimensional ((3 + 1)D) generalized nonlinear Schrödinger equation (GNLSE), we analyze the spatiotemporal propagation characteristics by intensity moments when a laser propagates in an inhomogeneous nonlinear medium. The different order intensity moment can describe the characteristics of a laser, and in the paper, the beam width (BW), the pulse width (PW), the skewness and the kurtosis parameter are calculated. The spatiotemporal propagation stability of the exact solutions is analyzed in detail by the second-order intensity moment. We find that when the diffraction and dispersion coefficients are the identical distributed functions, the BW and PW of the exact solutions are constants or vary periodically during nonlinear propagation. So, the spatiotemporal propagation of the exact solutions is stable. When the diffraction and dispersion coefficients are other coefficients, the BW and PW of the exact solutions vary irregularly due to the effect of a chirp. Thus the spatiotemporal propagation of the exact solutions is unstable. The results are helpful to the extendable investigation of nonlinear propagation and control of a laser pulse.     

Solitons in PT–symmetric optical lattices with spatially periodic modulation of nonlinearity

We study the existence and stability of solitons forming in PT–symmetric optical lattices with spatially periodic modulation of the local strength of the nonlinear media. We found that the spatial modulation of the nonlinearity significantly affects the stability of solitons in PT–symmetric optical lattices. With the decrease of the strength of nonlinear refractive index modulation, the soliton's stability domain increases, whereas with the increase of the period of nonlinear refractive index modulation, the corresponding soliton's stability range narrows. In addition, we also investigate the influence of variation of the amplitude of the linear PT–symmetric lattice potential on soliton dynamics, in the presence of spatially periodic modulation of nonlinearity.     

Three-dimensional Monte Carlo simulation of bulk fin field effect transistor

In this paper,we investigate the performance of the bulk fin field effect transistor(FinFET) through a threedimensional(3D) full band Monte Carlo simulator with quantum correction.Several scattering mechanisms,such as the acoustic and optical phonon scattering,the ionized impurity scattering,the impact ionization scattering and the surface roughness scattering are considered in our simulator.The effects of the substrate bias and the surface roughness scattering near the Si/SiO2 interface on the performance of bulk FinFET are mainly discussed in our work.Our results show that the on-current of bulk FinFET is sensitive to the surface roughness and that we can reduce the substrate leakage current by modulating the substrate bias voltage.