Compressible Limit of the Nonlinear Schrdinger Equation with Different-Degree Small Parameter Nonlinearities

The authors study the compressible limit of the nonlinear Schrdinger equation with different-degree small parameter nonlinearities in small time for initial data with Sobolev regularity before the formation of singularities in the limit system.On the one hand,the existence and uniqueness of the classical solution are proved for the dispersive perturbation of the quasi-linear symmetric system corresponding to the initial value problem of the above nonlinear Schrdinger equation.On the other hand,in the limi...     

YBa2Fe3O8+w的湿化学法制备以及电磁性质研究

本文成功采用湿化学法制备了高品质的YBa2Fe3O8+w(YBFO)材料,并利用XRD、M～T、R～T和SEM 等测试与分析手段研究了其结构、电导性质和磁性质.结果表明,YBFO在结构上具有与高温超导体YBa2Cu3O7(YBCO)高度的相似性,在电磁学行为上呈现出反铁磁(AFM)的半导体特征.YBFO与YBCO的相似...     

等离子体法制备钴基费-托合成催化剂及性能表征

钴基费-托合成催化剂以介质阻挡放电等离子体(DBD法)替代传统热焙烧过程来制备,从而可在低温分解前驱体以获得高分散催化剂.结果表明,DBD法分解前驱体效果与传统焙烧法相同,但更节能和快捷.尽管两种方法所得催化剂的比表面积相近,但DBD法制得催化剂的孔体积和孔径更大,Co分散度更高,且Co与载体间的相互作用更强,因而更难...     

Synthesis of amphiphilic tri-block copolymerpoly(vinylpyrrolidone)-b-poly(methyl methacrylate)-b-poly(vinylpyrrolidone) for the modification of polyethersulfone membrane

Well-defined amphiphilic tri-block copolymer PVP-b-PMMA-b-PVP was prepared for the first time via successive reversible addition fragmentation chain transfer(RAFT) polymerization using carboxyl-terminated trithiocarbonate as the RAFT agent.The structure of the copolymer was characterized using FTIR,GPC and ~1H NMR.The block copolymer could be directly blended with polyethersulfone(PES) as a macromolecule additive using N-methyl-2-pyrrolidone(NMP) as the solvent to prepare membranes. The water contact angles for the modified membranes decreased obviously,and therefore,the protein adsorption amount on the membrane surface decreased.     

Secondary metabolites from fungus Alternaria sp. CIB 108

A new compound,3-butyryl-6-[rel-(1S,2S)-1,2-dihydroxypropyl]-4-hydroxy-2H-pyran-2-one(1),was isolated from the solid fermented rice culture of Alternaria sp.CIB 108,along with three known ones,deoxyradicinin(2),3-epiradicinol(3),and 3- epideoxyradicinol(4).Their structures were elucidated on the basis of spectroscopic data.The single crystal X-ray diffraction was applied to further clarify the structure of 1.Furthermore,compounds 1-4 possessed no cytotoxicity against several cell lines(HeLa, HepG2,and Ros) and showed no antibacterial activity at 40μmol/L.     

A new phenylethanoid glycoside from Isodon sculponeatus

A new phenylethanoid glycoside,seulponisidc(1) was isolated from the aerial parts of Isodon sculponeatus(Vaniot) Kudo, along with six known compounds martynoside(2),verbascoside(3),(+)-hydroxypinoresinol-8-O- β-D-glucoside(4),cedrusin(5), 7-megastigmene-3S,5R,6R,7E,9S-tetrol(6) and 4-oxo- β-ionol- β-D-glucopyranoside(7).Their chemical structures were elucidated from physieochemical data and by acidic hydrolysis.     

Crosstalk reduction in multi-view autostereoscopic three-dimensional display based on lenticular sheet

A method to reduce crosstalk in multi-view autostereoscopic three-dimensional (3D) displays based on the lenticular sheet is proposed. Correcting the luminance values of each parallax image displayed on the display screen is employed. We analyze the causes of crosstalk. We deduce the formulas of crosstalk reduction according to the relationship between crosstalk coefficients of each parallax image observed through the lenticular sheet, luminance values of each parallax image displayed on the display screen,...     

High temperature property studies of the 6H-SiC MOS capacitor

N-type and p-type 6H-SiC metal oxide semiconductor (MOS) capacitor samples are fabricated with a typical method,and the high frequency capacitor voltage (C-V) curves of these samples are measured at temperatures ranging from 293 to 533 K.There exists huge difference between the n-type and p-type samples.Flat-band voltage shift of the n-type sample becomes larger with temperature rising,but that of the p-type sample have very little change.This may be caused by the residual Al in the p-type oxide.Both types ...     

环形激光二极管抽运棒状激光器中瞬态温度和热应力分析

直接从激光二极管发光强度的角分布出发,采用光线追迹方法获得激光棒内的热沉积分布,在此基础上采用热传导模型和热力模型,比较了不同抽运功率、不同棒半径下达到稳态温度分布的时间,并且对稳态和瞬态热应力进行了详细模拟计算。结果表明,采用环形激光二极管阵列侧面抽运的棒状激光器中的热效应问题十分严重,不同的抽运结构参量下,温度分布不同;达到稳态所需时间随棒半径增大而增加,而不受抽运功率的影响;抽运功率越大,棒内温差增大,热应力也越大;热破坏主要集中于激光棒中心区域和表面区域。     

SrAl2O4:Tb3+,Ce3+发光材料的合成与发光特性

以高温固相法合成SrAl2O4:Tb^3 ,Ce^3 发光材料,蓄光后在暗室中观察发出明亮的绿光。利用X射线粉晶衍射仪对其进行了物相测定,扫描电镜对其进行了晶相与显微结构分析,分析结果表明,合成物为α-SrAl2O4属于单斜晶系。利用荧光分光光度计进行了光谱分析,测定了所合成样品的激发光谱和发射光谱,研究了Tb^3 含量与合成荧光粉发光强度的关系,在SrAl2O4:Tb^3 体系中加入Ce^3 ,发现Ce^3 可将能量传递给Tb^3 ,对Tb^3 起到了敏化作用。