Radially polarized hyperbolic-cosine-Gaussian beam

Vector beams have attracted much interest recently. In this paper, focusing properties of the radially polarized hyperbolic-cosine-Gaussian beam are investigated. Simulation results show that the focal depth increases with increasing cosine parameter in the cosine term of the beam, while focal spot decreases simultaneously, namely, superresolution occurs. Focal depth increase velocity is quicker for larger cosine parameter, while the transverse focal spot shrinks more quickly for smaller cosine parameter. In addition, for two-portion concentric piecewise radially polarized hyperbolic-cosine-Gaussian beam with π phase shift in center circle portion, focal pattern evolves considerably with increasing cosine parameter, and the evolution principle differs for different radius of the center circle portion. Focal splitting and novel focal spots may appear. This kind of vector beam can be used in optical storage, optical manipulation, and lithography.     

Tunable gradient force of hyperbolic-cosine–Gaussian beam with vortices

Gradient force plays an important role in optical tweezers technique. In this paper, the tunable gradient force in focal plane of the hyperbolic-cosine–Gaussian (ChG) beam is investigated numerically. The ChG beam contains one spiral vortex and one non-spiral vortex. Simulation results show that the gradient force distribution can be altered considerably by decentered parameters of ChG beam, topological number of the spiral vortex, and vortex parameter of the non-spiral vortex. Many novel gradient force patterns can occur, which means corresponding optical traps may come into being, including ring optical trap, multiple-point trap pattern, line optical trap, rectangle trap pattern, and rhombus trap pattern. In addition, force pattern evolution principle may also differ significantly.     

亚纯系数的高阶线性微分方程的解的增长性

本文研究亚纯系数的高阶线性微分方程,当方程系数满足一定条件时,得到方程的每一非零亚纯解具有无穷级且超级为n.此外,还研究了非齐次线性微分方程的亚纯解.     

HYPER ORDER OF SOLUTIONS TO SOME LINEAR DIFFERENTIAL EQUATIONS IN THE UNIT DISC

In this paper, we investigate the growth of solutions to some linear diferential equations with analytic coefcients in the unit disc. When the coefcients of these equations have some special properties near a point on the boundary of the unit disc, the order and the hyper order of the solutions to these equations are estimated accurately. Especially, our conditions on the coefcients are more general and the results on the hyper order of the solutions are new to some extent.     

Construction and application of an electrochemical sensor based on graphene-MXene nanocomposites for baicalin detectionEI北大核心CSCD

Redox graphene-MXene(rGO-MXene) nanocomposites were prepared by ion polymerization and used to construct a highly sensitive electrochemical sensor for baicalin(BA) detection. The synergistic effect of rGO and MXene increased the specific surface area and electron transport capacity of the electrode, and significantly enhanced the electrochemical response of BA. The cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of BA on the sensor. Under the optimal conditions, the peak current exhibited a good linear relationship with BA concentration in the range of 0. 05-10 μmol / L, and the limit of detection was as low as 28 nmol / L. The method was applied to analyze traditional Chinese medicine preparations containing baicalin, such as Qingkailing Capsule and Sanhuang Tablets with good accuracy and spiked recovery. The results were highly consistent with those of high performance liquid chromatography, providing a technical means for the rapid and sensitive detection of traditional Chinese medicine preparations. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Iron carbonyl thioboronyls: effect of substitution of sulfur for oxygen in the viability of binuclear complexes toward dissociation reactions

The recent discovery of boronyl complexes of the type (R₃P)₂Pt(BO)X (R = cyclohexyl; X = halogen) makes of interest the chemistry of complexes of the related thioboronyl (BS) ligand. In this connection, the binuclear iron carbonyl complex Fe₂(BS)₂(CO)₈ is predicted by density functional theory to have a symmetrical unbridged structure similar to the valence isoelectronic Mn₂(CO)₁₀. Higher-energy unsymmetrical (OC)₅Fe → Fe(BS)₂(CO)₃ structures are also found as well as a doubly bridged Fe₂(BS)₂(CO)₆(µ-CO)₂ structure. The complex Fe₂(BS)₂(CO)₈ is predicted to be viable toward symmetrical dissociation into Fe(BS)(CO)₄ fragments. However, the unsymmetrical dissociation of Fe₂(BS)₂(CO)₈ into Fe(CO)₅ + Fe(BS)₂(CO)₃ is predicted to be exothermic by ~9 kcal mol^?1. The low-energy structures of the mononuclear Fe(BS)₂(CO)₃ include structures in which the two BS ligands have coupled to form a B₂S₂ ligand through B–B bond formation.     

Study on the algorithm of computational ghost imaging based on discrete fourier transform measurement matrix

We have developed a model and realized an algorithm for the calculation of the coefficient of coherent (direct) transmission of light through a layer of liquid crystal (LC) droplets in a polymer matrix. The model is based on the Hulst anomalous diffraction approximation for describing the scattering by an individual particle and the Foldy-Twersky approximation for a coherent field. It allows one to investigate polymer dispersed LC (PDLC) materials with homogeneous and inhomogeneous interphase surface anchoring on the droplet surface. In order to calculate the configuration of the field of the local director in the droplet, the relaxation method of solving the problem of minimization of the free energy volume density has been used. We have verified the model by comparison with experiment under the inverse regime of the ionic modification of the LC-polymer interphase boundary. The model makes it possible to solve problems of optimization of the optical response of PDLC films in relation to their thickness and optical characteristics of the polymer matrix, sizes, polydispersity, concentration, and anisometry parameters of droplets. Based on this model, we have proposed a technique for estimating the size of LC droplets from the data on the dependence of the transmission coefficient on the applied voltage.     

New macrocyclic compound as chiral shift reagent for carboxylic acids

[structure: see text] We have prepared a novel chiral macrocyclic compound 3 from a C2-symmetric aminonaphthol in a high yield. Enantiomeric acids have large nonequivalent chemical shifts (up to 0.80 ppm) in the presence of 3 in 1H NMR (500 MHz) spectra. Quantitative analyses of a series of mandelic acids with different enantiomeric purities show that host 3 is an excellent chemical shift reagent for chiral carboxylic acids.     

Effect of pressure on the selectivity for the esterification of ethylene glycol with propionic acid in supercritical CO2

The esterification of ethylene glycol with propionic acid was investigated in supercritical CO2 at 50.0 degrees C. The effect of pressure on equilibrium conversion and selectivity of ethylene glycol monopropionate (monoester) and ethylene glycol dipropinonate (diester) was studied systematically. It was shown that the equilibrium conversion and selectivity was nearly independent of pressure as pressure was lower than 9 MPa. At higher pressure, however, the yield and selectivity of the diester increased considerably, while those of the monoester decreased with increasing pressure. The main reason was that reactants and products distributed between the vapor phase and liquid phase at higher pressures. The solvent power of CO2 for the diester is stronger than that for the monoester. More diester molecules in the liquid phase were extracted into the vapor at higher pressures, which shifted equilibrium of the consecutive reversible reactions.     

求解隐式差分方程的并行算法

本文研究了求解隐式差分方程的并行算法,其基本想法是把差分方程组化为若干个子方程组来求解,文中给出了直接法和迭代法,证明了迭代法的收敛性。为了说明分段隐式迭代方法的有效性,文中针对扩散方程的具体例子给出了数值试验计算结果。