The Structural Determination of the Ozonides and Their Reaction with Stabilizel Phosphorus Ylides

The ozonides reacted with stabilized phosphorus ylides to give the α,β-unsaturated carbonylcompounds in high yield. The Z/E ratio is dependent on the substituent of the ozonide. Their possiblemechanism was described.     

拟圆周与交比

设(z_1,z_2,z_3,z_4)=((z_1-z_3)(z_2-z_4))/((z_1-z_4)(z_2-z_3))表示扩充复平面■~2上互不相同有序四点z_1,z_2,z_3,z_4的交比,利用交比刻画了圆周与拟圆周的几何性质,得到(1)■~2上的Jordan曲线Γ是圆周(或直线)当且仅当Γ上任意互不相同的有序四点z_1,z_2,z_3,z_4,满足|(z_1,z_4,z_2,z_3)| |(z_1,z_2,z_4,z_3)|=1; (2)■~2上的Jordan曲线Γ是拟圆周当且仅当存在常数c≥1,对Γ上任意互不相同的有序四点z_1,z_2,z_3,z_4,满足|(z_1,z_4,z_2,z_3)| |(z_1,z_2,z_4,z_3)|≤c．     

关于非线性规划问题的组合同伦内点法

文[1]在条件(C1)、(C2)和(C3)之下，利用组合同伦内点法讨论了非凸非线性规划问题K—K—T点的存在性，本文对条件(C2)和(C3)进行了改进和处理。     

Electrochemical Reduction of Oxygen on Multi-walled Carbon Nanotubes Electrode in Alkaline Solution

The multi-walled carbon nanotubes (MWNTs) electrode was constructed using polytetrafluoroethylene as binder, and the electrochemical reductive behavior of oxygen in alkaline solution was first examined on this electrode. Compared with other carbon materials, MWNTs show higher electrocatalytic activity, and the reversibility of O2 reduction reaction is greatly improved. The experiments reveal that the electrochemical reduction of O2 to HO2 is controlled by adsorption. The preliminary results illustrate the potential application of MWNTs in fuel cells.     

VIBRATION SIGNAL ANALYSIS AND FEATURE EXTRACTION BASED ON REASSIGNED WAVELET SCALOGRAM

The wavelet scalogram has been widely used for vibration signal analysis, but it has low frequency concentration at small scales and low time concentration at large scales owing to the limitation of Heisenberg-Gabor inequality. In addition, misleading interference terms would appear in the scalogram at some conditions. All of these would influence scalogram analysis seriously. In this paper, a reassignment method is used, which can improve the concentration of the scalogram and weaken the interference terms to a certain extent; thus, the readability of the scalogram can be improved. The experimental data for three kinds of faults in rotating machinery: rotor-to-stator rub, oil whirl, coupling misalignment and the actual measurement data from a Pumped Storage Power Generator Unit are analyzed by the scalogram and the reassigned scalogram, and the results by FFT analysis are also given. A comparison among three kinds of analysis results is carried out, and the comparison results indicate that the scalogram can not only reveal the time-frequency features of vibration signal but also highlight the components of low energy. Therefore, it is suitable to extract features of faults at an early stage.     

变系数波动方程所决定的控制系统的最小能量控制和快速控制问题

本文研究变系数波动方程所决定的控制系统的最小能量控制和快速控制问题 .在所讨论的系统精确可控的前提下 ,得到了系统的最小能量控制和快速控制的解析表达式     

关于拟圆性质的评注

设D是扩充复平面R-2中的单连通Jordan真子域,D*=R-2\D-是D的外部.本文肯定并证明 了K.Hag在1999年提出的如下两个悬而未决的问题:(1)D是Cigar域当且仅当D是OLC域; (2)D是Turning域当且仅当D*是Cigar域.     

拟圆的三个充要条件

设D是R2中的Jordan域,D*=R2＼D是D的外部,本文证明了拟圆的下面三个充要条件:(1)D是拟圆当且仅当D和D*都是弱拟凸域;(2)D是拟圆当且仅当D和D*都是弱Cigar域;(3)D是拟圆当且仅当D是弱一致域.     

平面波经小圆环衍射轴上光强特性分析

从标量衍射理论出发,采用瑞利-索末菲衍射边界条件,通过求解第一类瑞利-索末菲衍射积分得到平面波经圆环衍射后轴上的波函数,进而分析轴上的光强特性以及光强极值数量、位置和大小与衍射圆环内外孔径的关系.比较用传统的光强定义和精确定义得到的光强公式的偏差,以及偏差与内外半径的关系.并将圆环衍射向内半径为零和外半径为无穷大两个方向进行推广,即对圆孔和圆形障碍物两种情况下的衍射情况进行讨论.     

Dehydroaromatization of Methane with a Small Amount of Ethane for Higher Yield of Benzene

The dehydroaromatization of methane was investigated with addition of a few ethane. A high benzene yield was achieved at a higher space velocity. The addition of CO2 could improve the stability.