Boundedness for Commutators of Multilinear Fractional Integral Operators

本文利用SHArP极大函数的估计,证明了一类由多线性分数次积分算子和bMO(r--n)函数生成的交换子的l--P(r--n)有界性.By some estimates for the sharp maximal functions,the L--p(R--n)-boundedness for a class of commutators for multilinear fractional integral operators with BMO(R--n) functions are obtained.SupportedbytheNSFC(No.G10571122

Effect of growth temperature on composition control for YBCO precursor films fabricated by vapor codeposition

The promising physical properties of multi-element functional nanofilms are essentially dependent on each particular nanostructure,which could be greatly altered by the change of stoichiometry[1].The vapor deposition techniques are good at controlling the composition of deposited atoms,and theref..

Influence of post-annealing ambient on the superconducting properties and microstructure of YBa_2Cu_3O_7-δ films

Post-annealing processes are crucial for the ex-situ growth of YBa2Cu3O7-δ(YBCO)superconducting film[1].Through annealing,the deposited atoms reorganize themselves,the amorphous precursor films transform into single crystals with orthogonal lattice structure[2,3].Without suitable annealing,the pr..

Effect of humidity on microstructure and properties of YBCO film prepared by TFA-MOD method

Epitaxial YBCO superconducting films were deposited on the single crystal LaAlO3 (001) substrate by metal organic deposition method. All YBCO films were fired at 820 degrees C in humidity range of 2.6%-19.7% atmosphere. Microstructure of YBCO thin films was analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Superconducting properties of YBCO films were measured by four-probe method. XRD results showed that the second phase (such as BaF2)and a-axis-oriented grains existed in the films prepared at 2.6% humidity condition; a-axis-oriented grains increased in the film prepared at higher than 4.2% humidity condition; almost pure c-axias-oriented grains existed in the films fired at 4.2% humidity condition. Morphologies of the YBCO films showed that all films had a smooth and crack-free surface. YBCO film prepared at 4.2% humidity condition showed J(c) value of 3.3 MA/cm(2) at 77 K in self-field

Effect of humidity on microstructure and properties of YBCO films prepared by Electron Beam Coevaporation

YBCO superconducting films were prepared by Electron Beam Coevaporation method. All the YBCO films were annealed at 760&deg;C in humidity range of 2.3%&ndash;9.5%. Microstructure of the YBCO thin films was analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Superconducting properties of the YBCO films were measured by electromagnetic induction method. XRD results showed that c-axis-oriented grains existed in the YBCO films. Morphologies of the YBCO films showed that all the films had a smooth and crack-free surface. YBCO films prepared at 7.3% humidity condition showed J c value of 4.6 MA cm&minus;2 at 77 K in self-field.</div

三重疗法治疗雄激素性脱发疗效分析

目的:通过三重疗法治疗雄激素性脱发,并进行疗效分析。方法:66例雄激素性脱发病人随机分为试验组与针刺组,每组各33例。试验组采取针刺、梅花针联合实按灸疗法,针刺组采取针刺疗法。记录两组患者的疗效及伴随症状评分情况。结果:试验组的总有效率为81. 82%,针刺组的总有效率为57. 58%。两组的疗效比较差异具有统计学意义(P <0. 05)。治疗后,试验组的伴随症状评分均低于针刺组,差异均具有统计学意义(P <0. 05)。结论:电针、梅花针联合实按灸疗法治疗雄激素性脱发疗效显著,临床上具有推广及应用价值。中国中医科学院“十三五”重点领域研究专项第一批(No.ZZ10-011-1-2

An Inquiry into the Fate of Private Universities in the 1950’s Reform of Higher Education

文章简述了 20 世纪 50 年代中国私立大学的改造和合并,以及院系调整中私立大学的撤销过程,对私立大学在中国大陆发展中断的原因进行了分析探讨。The paper mainly discusses the private universities in the restructuring of Chinese universities in 1950s, and also analyzes the fate of private universities

YBa 2Cu 3O 7-delta superconducting films prepared by low pressure post-annealing

YBa2Cu3O7-deltaprecursor films are deposited on 2" LaAlO3wafer by the co-evaporation technique using Y, BaF2and Cu as evaporation sources. After deposition, the films are annealed at low-pressure atmosphere with the composition of oxygen and water vapour. Compared with the normal pressure annealing, it is shown that low pressure can greatly improve the superconducting properties of 2" YBCO films with thickness larger than 500 nm, as the microcrack on films surface becomes unobservable the microwave surface resistance is greatly reduced. Furthermore, it is also revealed that the optimal processing window for making high quality superconducting YBCO films through ex-situ process is relatively small, therefore the ambient in annealing furnace is crucial important and should be precisely controlled

中国科学院力学研究所高温气体动力学国家重点实验室;

YBa2Cu3O7-x(简称YBCO)高温超导薄膜具有极低的微波表面电阻,在诸如微波通讯等领域,应用前景重要而广阔。本文采用我们自主研制的多元电子束物理气相沉积系统生长YBCO薄膜。首先,在直径2英寸的La Al O3(简称LAO)单晶衬底上成功制备了厚度约500nm的YBCO薄膜。然后,在低压气氛中退火,并考察了退火过程中,环境气氛压力对YBCO薄膜结构和超导性能的影响。X射线衍射(XRD)、扫描电镜(SEM)和超导性能测试结果表明,低压气氛下制备的YBCO薄膜具有良好的织构和平整致密的

Study of YBCO films prepared by E-beam evaporation

采用电子束沉积制备YBCO超导薄膜,研究了760℃-840℃的不同退火温度下高温热处理对YBCO薄膜双轴织构,表面形貌及超导性能的影响.超导临界电流密度测试,X射线衍射(XRD)和扫描电镜(SEM)的结果表明,退火温度在在800℃时,YBCO薄膜具有良好的织构和平整致密的表面形貌,在77K自场下的临界电流密度J可达4.2×106/cm