Structure elucidation of four prenylindole derivatives from Streptomyces sp. isolated from Ailuropoda melanoleuca feces

Four new prenylindole derivatives, (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indole (1), (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indolin‐2‐one (2), and an unseparated mixture of (Z)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3a) and (E)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3b) with a ratio of 3 : 2, were isolated from the culture broth of a streptomycete isolated from Ailuropoda melanoleuca feces. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques. The absolute configuration of 1 was determined by Mosher's method. Copyright © 2013 John Wiley & Sons, Ltd.     

非齐次线性差分方程的Cm解[英文]

设c0,c1,…,cn均为实的常数，F（x)是个从R到R的C^m映射。本文讨论了非齐次线性差分方程∑i=1ncif(x i)=F(x)的C^m(m≥0）的存在性和唯一性。     

伴随着分子内电荷分离的分子内转动模型的时间分辨荧光光谱研究

本文采用时间分辨荧光光谱方法,考查了两种7-胺基香豆类素衍生物分子在不同溶剂中的荧光辐射弛豫过程,研究了环境因素对伴随着分子内电荷转移的分子内转动激发态(TICT)弛豫过程的影响。结果说明TICT态是非刚性香豆素分子激发态无辐射弛豫路径之一,这一过程受到环境介质的极性、粘度和温度的影响。并指出了在考虑粘度影响时,须对DSE理论进行修正,同时提出了TICT态存在位垒的观点。     

Synthesis of NiFe2O4 Powders Well Defined in Size and Morphologies

The uniform NeFe2O4 powders with different particle size and morphologies (octahedral, cubic and spherical) have been prepared from different precursors via hydrothermal process. The nanocrystallines derived from precursor B in the weak alkali solution (pH≥10) are superparamagnetic.     

New smooth C-functions for symmetric cone complementarity problems

In this paper, with the help of the Jordan-algebraic technique we introduce two new complementarity functions (C-functions) for symmetric cone complementary problems, and show that they are continuously differentiable and strongly semismooth everywhere. The work was partly supported by the National Natural Science Foundation of China (10671010, 70471002).     

MULTIPLE LAYER BEHAVIOR OF BOUNDARY VALUE PROBLEM FOR SINGULARLY PERTURBED n-TH ORDER NONLINEAR DIFFERENTIAL EQUATION

In this paper,we study the singular perturbation of boundary value problem for a class of n-th order nonlinear differential equation,the solution is shown to exhibit multiple layer behavior.According to different layers and by introducing extended variable,we obtain the uniformly effective asymptotic expansion with different boundary layer correction term.     

A Novel Feeding Scheme for Bandwidth Enhancement of Suspended Planar Antenna

A suspended planar antenna with a novel feeding structure is proposed for bandwidth enhancement. This feeding structure can provide extra degrees of freedom to tune the antenna for compensating for the large inductance induced by the long feeding probe. An impedance bandwidth of 56% for VSWR<2 is obtained. Simulated and measured results are compared and good agreements are observed.     

具有不可缩小Beltrami系数的拟共形映射

本文讨论了不可缩小Beltrami系数与无限小不可缩小Beltrami系数的局部 性与整体性的关系;并通过烟囱形区域上仿射拉伸的实例,指出构造一类极值的具有 非常数模的不可缩小Beltrami系数与无限小不可缩小Beltrami系数的方法.     

An Unexpected and Green Synthetic Protocol for Ethyl 1‐Aroyl/Aroylmethyl‐5‐methyl‐3‐methylthiopyrazole‐4‐carboxylates: High Regioselectivity in Alkylation and Acylation Reactions between N‐1 and N‐2 of a Pyrazole Ring

Two series, totaling twelve, of new compounds, ethyl 1‐aroyl/(aroylmethyl)‐5‐methyl‐3‐methylthiopyrazole‐4‐carboxylates ( 5 / 6 ), have been synthesized via highly regioselectively acylation and alkylation reactions of ethyl 3‐methyl‐5‐methylthio‐1 H‐pyrazole‐4‐carboxylate ( 2a ) with aroyl chloride ( 3 ) and eco‐friendly reagents alpha‐tosyloxysubstituted acetophenones ( 4 ), respectively, and a green protocol has been developed. The acylation reactions were carried out under ultrasound irradiation, and the alkylation reactions were under microwave irradiation and ultrasound irradiation, respectively. Conventional reaction conditions, as well as the use of alpha‐bromosubstituted acetophenone ( 4 ′) have also been applied in the synthesis of some randomly selected compounds in both series and have generated identical compounds correspondingly. Unexpected structures of compounds were unambiguously determined by X‐ray crystallographic analysis.