Sonochemical synthesis and optical properties of amorphous ZnO nanowires

Large-scale amorphous wire-like ZnO nanostructures were prepared by ultrasonic spray pyrolysis Zn(CO)₅ without involvement of any template or patterned catalyst. The as-obtained amorphous ZnO nanowires were characterized using scanning/transmission electron microscopy, X-ray diffraction/photoelectron spectroscopy, energy-dispersed X-ray spectrometry, selected area electronic diffraction, and high-resolution transmission electron microscopy. The results reveal the as-made noncrystalline samples are about 30–60 nm in diameter and several tens of microns in length and the growth mechanism is tentatively proposed as the self-assembly soft template mechanism. The photoluminescence spectra in all of the as-studied specimens exhibit one wide visible emission peak in about 508 nm. The corresponding PL intensity greatly increased with an annealing temperature, which has an application for a high efficiency vacuum fluorescent displays and a low-voltage phosphor.     

Positron-impact ionisation of atomic hydrogen in the presence of a bichromatic laser field

The positron impact-ionisation of atomic hydrogen in the presence of a linearly polarised bichromatic field is investigated in the first Born approximation.The field is composed of a fundamental frequency and its second harmonic.The state of positron in the field is described by the Volkov wavefunction,and the continuum state of the ejected electron is described by the Coulomb-Volkov wavefunction.The dressed ground state of target is a first order time-dependent perturbative wavefunction.The triple differential cross sections and their dependencies on laser field parameters are discussed and compared with the results modified by a monochromatic field.Numerical results show that the coherent phase control is significant and the laser-assisted ionisation cross sections caused by positron and electron are different.     

Urinary Metabolites of Isoliquiritigenin in Wistar Rats using UHPLC–TOF–MS-based Xenometabolomics

Isoliquiritigenin, a chalcone found in licorice root and many other plants, has shown potential antioxidant, estrogenic and antitumor activities. The present study was to investigate urinary metabolism of isoliquiritigenin in Wistar rats by ultra-high pressure liquid chromatography coupled to electrospray ionization TOF–MS (UHPLC–TOF–MS)-based xenometabolomics. Urine samples were collected before and after oral administration of isoliquiritigenin, and analyzed by UHPLC–TOF–MS. After deconvolution, the resulting data matrices were subjected to multivariate data analysis. Projection to latent structures discriminant analysis was performed to screen the metabolites. Fifteen urinary metabolites of isoliquiritigenin were screened out and 13 of them were further identified by Agilent MassHunter Software. The results of this work show that UHPLC–TOF–MS-based xenometabolomics was able to comprehensively identify the metabolites of phytochemicals and may represent a valuable tool for monitoring the food consumption.

     

KBBF与B_2O_3的FT－IR研究

本文用ＦＴ－ＩＲ研究了不同组成的ＫＢＢＦ与Ｂ＿２Ｏ＿３的红外谱图，得出了Ｂ＿２Ｏ＿３含量对有关谱线强度比的定量曲线．这对ＫＢＢＦ晶体的制备具有一定的参考价值．     

Boiti－Leon－Manna－Pempinelli方程的Painleve性质Backlund变换、共形不变性和新的2＋1维Sinh－Gordon方程

首先利用１＋１维ＫｄＶ方程的奇性流形方程的共形不变性，重新给出了１＋１维的ｓｉｎｈ－Ｇｏｒｄｏｎ万程。利用相同的思想万法，证明了ＢＬＭＰ万程的Ｐａｉｎｌｅｖé性质，给出ＢＬＭＰ方程的Ｂａｃｋｌｕｎｄ变换的同时，利用ＢＬＭＰ方程的Ｓｃｈｗａｒｔｚ形式的共形不变性，得到了一个新的２＋１维可积ｓｈＧ方程。     

具有广义协变的包含重力场贡献的重力场方程

利用半度规λ^(α)_μ表象的数学工具定义一个对广义坐标具有协变形式的重力场矢势函数ω^(α)_μ≡-cλ^(α)_μ，给出一个具有广义协变的包含重力场贡献的重力场方程R_μν-g_μνR/2+Λg_μν=8πG(T^(Ⅰ)_μν+T^(Ⅱ)_μν) 关键词： 重力场方程 协变形式 能量-动量张量 量子化     

窄线宽、高光束质量的外腔双反馈激光二极管阵列

设计了一种离轴双反馈外腔能够有效地改善激光二极管阵列的线宽和光束质量。闪耀光栅和高反镜之间形成了一个共振腔。通过调整光栅和高反镜之间的倾角可以选定一个空间模在共振腔中放大。将一个半波片插入外腔中的光栅反馈支路,来控制反馈光的数量,激光从光栅反馈支路输出。运用这项技术,在工作电流16 A,可以把激光二极管阵列的输出线宽压缩到0.15 nm,光束束宽积减小到283 mm·mrad。由于光栅的锁定作用,中心波长几乎不随温度的变化而改变。在工作电流17 A时,输出激光的功率为2.44 W,斜率效率为0.5 W/A。     

Facile Synthesis of Five-membered Phosphoroheterocycles Bearing N-P-N and S-P-N Moieties

In past decades, Lawesson reagent (LR) has aroused extensive interests of chemists. Various papers on LRs structure, physical and chemical properties appeared in literature1~5, application of its unique reactivity in the synthesis of bio-active compounds also attracted much attention6,7. In particular, some potential bio-active phosphorus heterocycles could be novelly prepared by reacting LR with proper functional compound8. Peterson reported that the reaction of LR with 3-oxo-propaneni…     

超新星(续)

超新星爆炸是发生在宇宙空间中极为壮观、丰富多彩和引人入胜的重要现象,涉及许多有趣的、尚待探索的物理学研究领域和天体物理学及宇宙学若干相关分支的重要应用.本文试图描述超新星现象研究在各方面的重要意义,提供基本观测事实和理论框架信息以及介绍我们正在从事的部分相关研究工作.