反应扩散系统中波传播的锁频现象

在空间延展系统中,当增强外部光强时,作者观察到波传播的N：N-1（N≥2）锁频现象.此现象是在光敏BZ反应实验中观察到的.通过构建一个映射函数,发现在波周期和外部光强的关系中存在魔鬼阶梯,并且此阶梯与实验数据相吻合.     

Investigation of hydrogen bonding in neat dimethyl sulfoxide and binary mixture (dimethyl sulfoxide + water) by concentration-dependent Raman study and ab initio calculation

In this study,our vibrational spectroscopic analysis is made on hydrogen-bonding between dimethyl sulfoxide and water comprises both experimental Raman spectra and ab initio calculations on structures of various dimethyl sulfoxide/water clusters with increasing water content.The Raman peak position of the v(S=O) stretching mode of dimethyl sulfoxide serves as a probe for monitoring the degree of hydrogen-bonding between dimethyl sulfoxide and water.In addition,the two vibrational modes,namely,the CH 3 symmetric stretching mode and the CH 3 asymmetric stretching mode have been analysed under different concentrations.We relate the computational results to the experimental vibrational wavenumber trends that are observed in our concentration-dependent Raman study.The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the nature of the hydrogen bonding and the structures of the hydrogen-bonded complexes studied.     

Phase mismatching analysis of third-harmonic generation in BBO crystal

<正>Phase mismatching for third-harmonic generation(THG) in barium metaborate(BBO) crystal is investigated in detail.Upon using BBO crystal in the TypeⅠ(oo→e) scheme,in the two independent planes (principal section of the crystal and the plane normal to principal section),when the input second-harmonic beam deviates from the expected direction,phase mismatching occurs and the angle deviation produces different effects on the conversion efficiency.We numerically simulate these two cases of phase mismatching and identify the relation between the conversion efficiency and the deviation angle in the air.The computational results indicate that the phase matching tolerance in the principal section is 0.2°(in the air),while the phase matching tolerance in the plane normal to principal section is 4.5°(in the air).After conducting a lab experiment,the results agree perfectly with the computational results,indicating that the deviation angle in the principal section has a greater effect on the conversion efficiency.     

Diffraction grating single-shot correlation system for measurement of picosecond laser pulses

We study and experimentally demonstrate a sensitive single-shot correlation system in which only a diffraction grating is used to produce a transverse time delay (TTD) in the reference pulse.The mechanism of the TTD introduced by the grating and the formation of the relative time delay (RTD) in the noncollinear correlation system are analyzed in detail.By using our system,we successfully measured the temporal duration of picosecond laser pulses,and a time resolution of ～0.047 ps is obtained at 1047 nm.The impact of the grating dispersion and the second harmonic beam walk-off effect on the measurement are considered.     

二维二氧化硅改性聚环氧乙烷基固态聚合物电解质用于增强锂离子电池性能

通过改性由酸蚀二维蛭石制备的二维二氧化硅,得到带正电荷的二维介孔二氧化硅(PSN⁺)纳米片,并将PSN⁺用作聚环氧乙烷(PEO)基固体聚合物电解质(SPEs)的填料。由于PSN⁺具有丰富的正电荷,PSN⁺与锂盐解离的阴离子能够有效结合,从而促进锂离子的运输,获得较好的锂离子转移数。在50 ℃时,基于PSN⁺的SPEs表现出较高的离子电导率(7.5×10^-5 S·cm^-1),锂离子迁移数为0.30,稳定电压窗为4.41 V。因此,组装后的LiFePO₄锂电池在50 ℃、0.2C下具有优异的初始放电比容量(155.7 mAh·g^-1),在循环100次后容量保持率为97.1%。     

Stochastic Simulation of Turing Patterns

We investigate the effects of intrinsic noise on Turing pattern formation near the onset of bifurcation from the homogeneous state to Turing pattern in the reaction-diffusion Brusselator. By performing stochastic simulations of the master equation and using Gillespie＇s algorithm, we check the spatiotemporal behaviour influenced by internal noises. We demonstrate that the patterns of occurrence frequency for the reaction and diffusion pro- cesses are also spatially ordered and temporally stable. Turing patterns are found to be robust against intrinsic fluctuations. Sfochastic simulations also reveal that under the influence of intrinsic noises, the onset of Turing instability is advanced in comparison to that predicted deterministically.     

一维等离子体光子晶体的带隙研究

采用时域有限差分方法(FDTD),结合等离子体计算中的分段线性电流密度卷积技术(PLJERC)对一维等离子体光子晶体(1D-PPC)进行了数值模拟,给出了微分高斯脉冲在一维等离子体光子晶体中的传播过程。计算得到的带隙结构与K-P模型方法的结果一致。计算并分析了等离子体频率、介质介电常数、等离子体-介质层的厚度比以及周期厚度对一维等离子体光子晶体带隙结构的影响。     

离子型稀土矿浸出液除杂与沉淀过程固液强化分离研究

离子型稀土矿浸出液除杂和产品沉淀过程中,高效固液分离对全工艺连续化生产和产品质量提升具有重要作用,也是整个离子型稀土生产流程自动化、智能化的关键步骤。研究表明：在浸出液除杂、沉淀工序添加0.25 g·m^-3 JH2002絮凝剂,利用其电性中和作用和吸附架桥作用,可使Al(OH)₃胶体、碳酸稀土颗粒迅速团聚形成絮凝体,进而加速沉降过程;浸出液循环除杂过程的沉降速率为31.43 mm·min^-1,除杂上清液循环沉淀碳酸稀土产品过程的沉降速率为24.67 mm·min^-1。碳酸稀土产品经煅烧后,所得混合稀土氧化物产品的稀土总量为93.8%,主要杂质Al₂O₃,Fe₂O₃,SiO₂含量均很低,优于GB/T 20169-2015《离子型稀土矿混合稀土氧化物》标准值。此外,经过循环絮凝沉降的沉淀母液用于离子型稀土矿浸取,基本不会对浸出结果产生影响。     

一种新型含硒有机锗化合物的合成及其抗癌活性

合成了一种新型的含硒有机锗化合物 ,其结构经元素分析 ,IR和1HNMR表征。生物活性结果表明当化合物浓度为 10 -4mol·L -1时 ,对人体肝癌细胞的生长抑制率达 81.4 %。