高精度格式非线性权的统计谱特性分析

分析激波捕捉格式/混合格式中常用的非线性权和激波识别器在谱空间中的性质.设计一套分析非线性权和激波识别器在傅里叶空间性质的统计谱特性分析方法;利用该方法对不同的非线性权和激波识别器在傅里叶空间的性质进行详细分析,给出不同非线性权和激波识别器的统计特性,并比较优劣.分析方法和结论有助于深入理解非线性格式/混合格式在数值计算中的表现,并为设计高分辨率非线性格式提供理论支撑.     

Generation of nanosecond 2.65μm pulses and pulse narrowing in fiber-bulk Ho3+:YAG laser pumped gain-switched Cr^2+:Cd Se laser

The generation of mid-infrared pulsed lasers was achieved in a Ho3+:YAG laser pumped gain-switched Cr^2+:Cd Se laser system with the shortest pulse duration of 4.15 ns.With a pump pulse duration of 50 ns and pump power of 2.7 W,the gain-switched Cr^2+:Cd Se laser achieved over 10 times pulse narrowing,obtaining the maximum peak power of 5.7 k W.The optical-to-optical conversion efficiency was 3.7%,which could be further improved with better crystal surface polishing quality.The laser central wavelength was measured to be 2.65μm with a bandwidth(FWHM)of 50 nm.In addition,the parameter optimization for suppressing the pulse tail was discussed,while the long cavity and high output transmissivity contributed to obtaining the single-peak pulses.     

[Ni(phen)2(3,5-DMBA)](m-MBA)2(H2O)2配合物的合成、晶体结构及电化学分析

The title complex of nickel (II) with 3,5-dimethylbenzoic acid, m-methylbenzoic acid and 1,10- phenanthroline was synthesized and characterized. Crystal data for this complex: triclinic, space group P1, a=1.198 5(2) nm, b=1.315 3(2) nm, c=1.531 8(3) nm, α=92.602(3)°, β=103.292(3)°, γ=114.849(3)°, V=2.104 7(6) nm³, D_c=1.361 g·cm^-3, Z=2, F(000)=902, final GooF=1.071, R₁=0.067 2, wR₂=0.155 5. The crystal structure shows that the nickel ion is coordinated with four nitrogen atoms of two 1,10-phenanthroline molecules and two oxygen atoms of one 3,5-dimethyl benzoic acid molecule, forming a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex was also investigated. CCDC: 286966.