热力联合作用弹性薄圆板的弯曲与屈曲

 导出了热力联合作用下弹性薄圆板的弯曲动力响应控制方程,讨论了其弯曲变形特点及影响失效的因素。分析表明在短时热能沉积作用下,热屈曲是弹性薄板失效的主要方式之一;反鼓包或反冲塞是热屈曲的后继行为;增加外载和热能沉积功率水平都将加速热屈曲的发生;材料的温度相关性与热能沉积的时空分布对薄板的力学行为都有重要影响,同为产生和影响热剪切失效(反冲塞)的重要因素。     

A compact numerical algorithm for solving the time‐dependent mild slope equation

The mild slope equation has been widely used to describe combined wave refraction and diffraction. In this study, a new numerical algorithm is developed to solve the time‐dependent mild slope equation in a second‐order hyperbolic form. The numerical algorithm is based on a compact and explicit finite difference method that is second‐order accurate in both time and space. The algorithm has the similar structure to the leap‐frog method but is constructed on three time levels for the second‐order time derivative term. The numerical model has the capability of simulating transient wave motion by correctly predicting the speed of wave energy propagation, which is important for the real‐time forecast of the arrival time of storm waves generated in the far field. The model is validated against analytical solution for wave shoaling and experimental data for combined wave refraction and diffraction over a submerged elliptic shoal on a slope (Coastal Eng. 1982; 6 :255). Lastly, the realistic scale Homma's island (Geophys. Mag. 1950; 21 :199) is studied with the use of various wave periods of T = 720s, T = 120 s, and T = 24 s. These wave periods correspond to long, intermediate, and short waves for the given topography, respectively. Comparisons are made between numerical results and existing analytical solutions in terms of the wave amplification around the island, which serves as the indicator for the potential wave runup. Excellent agreements are obtained. The model runs on a PC (Pentium IV 1.8GHz) and the computer capacity allows the computation of a mesh system up to 3000 × 3000, which is equivalent to about 150 × 150 waves or a large area of 540km × 540km for a wave train with the period of T = 60 s. Copyright 2004 John Wiley & Sons, Ltd.     

基于内反射效应的可变光学衰减器

提出一种基于内反射原理的可变光学衰减器，这种利用一加长的棱镜和涂于棱镜上下两底面的SiO2薄膜的简单结构，使随入射角变化的反射光实现弱偏振相关和大动态范围的衰减。     

低剂量三氯化钐对实验性非胰岛素依赖型糖尿病大鼠胰岛的影响

观察了经腹腔注射低剂量三氯化钐（０．０５ｍｇ／ｋｇ）对链脲佐菌素引志的非胰岛素依赖型糖尿病（ＮＤＩＤＤＭ）大鼠胰岛形态和功能的影响。结果表明，三氯化钐治疗组糖耐量改善、血清胰岛水平长高、血清胰镐血糖素水平降低、平均单个胰岛面积和胰岛β细胞数量明显增多，肝细胞内糖原含量增多。提示低剂量三氯化钐对实验性ＮＩＤＤＭ大鼠有一定的治疗作用。     

Magnesium(II) Complexes with High Emission: The Distinct Charge‐Transfer Process from Transition Metal

Generally, the first‐row transition‐metal complexes are notorious in luminescence materials because of their metal‐ligand charge transfer in emission process. Herein, we rationally used magnesium instead the first‐row transition metal to coordinate with 2‐(anthracen‐9‐yl)‐1H‐imidazo[4,5‐f][1,10]phenanthroline (AIP) in the construction of luminescent complexes. Further investigation revealed AIP could work as detector for quantitative determination of Mg²⁺ cation. Comparing to other divalent cations, this fluorescence sensor exhibited high selectivity for the quantitative determination of Mg²⁺ with the low limit of detection (5 × 10^–7 m ). Through X‐ray single crystal diffraction, the crystal structures of [Mg(AIP₂)(NO₃)₂ · (H₂O)₄] ( 1 ), [Mn(AIP)(NO₃) · EtOH] ( 2 ), and [Co₂(AIP)₂Cl₄ · (MeOH)₂] ( 3 ) were observed in various arrangements. The theory calculations based on crystal structures indicated the Mg^II complex undergoes distinct charge‐transfer process from other transition‐metals based compounds, in which charge‐transfer excited‐state lifetimes were deactivated rapidly through metal‐to‐ligand charge‐transfer (MLCT) process. This study provided insight into construction of luminescence compounds by using d⁰ metals in main groups instead of transition metals.     

Accurate prediction of vertical electronic transitions of Ni(II) coordination compounds via time dependent density functional theory

Time dependent density functional theory calculations are completed for five Ni(II) complexes formed by polydentate peptides to predict the electronic absorption spectrum. The ligands examined were glycyl‐glycyl‐glycine (GGG), glycyl‐glycyl‐glycyl‐glycine (GGGG), glycyl‐glycyl‐histidine (GGH), glycyl‐glycyl‐cysteine (GGC), and triethylenetetramine (trien). Fifteen functionals and two basis sets were tested. On the basis of the mean absolute percent deviation (MAPD), the ranking among the functionals is: HSE06 ∼ MPW1PW91 ∼ PBE0 > ω‐B97x‐D ∼ B3P86 ∼ B3LYP ∼ CAM‐B3LYP > PBE ∼ BLYP ∼ BP86 > TPSS > TPSSh > BHandHLYP > M06 ≫ M06‐2X. Concerning the basis sets, the triple‐ζ def2‐TZVP performs better than the double‐ζ LANL2DZ. With the functional HSE06 and basis set def2‐TZVP the MAPD with respect to the experimental λ_max is 1.65% with a standard deviation of 1.26%. The absorption electronic spectra were interpreted in terms of vertical excitations between occupied and virtual MOs based on Ni‐d atomic orbitals. The electronic structure of the Ni(II) species is also discussed.     

Role of doping and sheet size in tailoring optoelectronic properties of germanene: A TDDFT study

Germanene is a novel 2D material with promising optoelectronic properties, tuning of which is to be explored. This work demonstrates that doping and increasing the sheet size can alter optical and electronic properties of germanene via perturbation of the band structure. This feature has also been observed in other nanostructures, notably, silicon nanostructures, and may be attributed to quantum confinement effects. Our main findings on H‐terminated germanene are, (i) band gap can be reduced by 30%, (ii) exciton binding energy can be reduced by 60%, and (iii) absorption spectra can be tuned from UV to visible range. We employ time‐dependent density functional theory to investigate the role of dopants, boron (B), phosphorus (P), carbon (C), silicon (Si), and zirconium (Zr). Width of the germanene sheet is varied from 0.78 nm to 2.78 nm. Frequency and energy calculations are carried out to analyze the infrared (IR) and ultra‐violet (UV)‐visible (VIS) spectra.     

A Note on Symmetries and Generalized W∞ Algebra of the Modified KP Equation

Some remarks on the paper Symmetries and generalized W algebra of the modified KP equation (S. Y. Lou and G. J. Ni, Lett. Math. Phys. 34 (1995), 327–331) are given. It is pointed out that if we consider the inverse operator of a differential operator to be a linear operator, the vector fields nv(f) defined in the above Letter are not certain to be symmetries of the modified KP equation under consideration.     

Exact quantum solutions of general driven time‐dependent quantum quadratic system

We studied the general time‐dependent linear and quadratic system via dynamical symmetries. In an algebraic framework, we obtained exact solutions of the evolution operators, propagators, and wave functions of the general time‐dependent linear and quadratic system. To illustrate our calculations, we discuss a few special cases, including a particle driven by a monochromatic electric field, and cases of oscillatory, linear, or monotonic with respect to the time of the quadratic system. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Quantum dynamics of inelastic scattering with a moving grid

The time‐dependent discrete variable representation (TDDVR) of a wave function with grid points defined by the Hermite part of the Gauss–Hermite (G‐H) basis set introduces quantum corrections to classical mechanics. The grid points in this method follow classical trajectory and the approach converges to the exact quantum formulation with sufficient trajectories (TDDVR points) but just with a single grid point; only classical mechanics performs the dynamics. This newly formulated approach (developed for handling time‐dependent molecular quantum dynamics) has been explored to calculate vibrational transitions in the inelastic scattering processes. Traditional quantum mechanical results exhibit an excellent agreement with TDDVR profiles during the entire propagation when enough grid points are included in the quantum‐classical dynamics. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005