Static response analysis of structures with interval parameters using the second-order Taylor series expansion and the DCA for QB

In this paper, based on the second-order Taylor series expansion and the difference of convex functions algorithm for quadratic problems with box constraints(the DCA for QB), a new method is proposed to solve the static response problem of structures with fairly large uncertainties in interval parameters. Although current methods are effective for solving the static response problem of structures with interval parameters with small uncertainties, these methods may fail to estimate the region of the static response of uncertain structures if the uncertainties in the parameters are fairly large. To resolve this problem, first, the general expression of the static response of structures in terms of structural parameters is derived based on the second-order Taylor series expansion. Then the problem of determining the bounds of the static response of uncertain structures is transformed into a series of quadratic problems with box constraints. These quadratic problems with box constraints can be solved using the DCA approach effectively. The numerical examples are given to illustrate the accuracy and the efficiency of the proposed method when comparing with other existing methods.     

五羰基铁光催化烯丙基苯类化合物的异构化反应的研究

本文研究了以五羰基铁为催化剂,使不同取代基的烯丙基苯类化合物进行光异构化反应。苯环上不同极性的取代基对烯丙基苯类化合物异构化速度的影响也不同。烯丙基苯类化合物的异构化反应是一级反应。由活化能E_a及不同极性取代基对反应的影响,对它们可能的机理模型作了进一步讨论。     

Reaction of oxazirconacycloheptenes with aldehydes mediated by CuCl: one-pot synthesis of tetrahydrofuran derivatives from four different components involving two molecules of the same or different aldehydes, an ethylene and an alkyne

Reaction of zirconacyclopentenes with 2 equiv. of the same aldehydes in the presence of 1 equiv. of CuCl from −78 °C to room temperature afforded tetrahydrofuran derivatives in good isolated yields upon hydrolysis with aqueous 3 N HCl. Oxazirconacycloheptenes, generated in situ from zirconacyclopentenes with one aldehyde was found to be the reactive intermediate. When treated with a second aldehyde and CuCl, an oxazirconacycloheptene gave a tetrahydrofuran derivative comprised of four different components involving an alkyne, an ethylene and two different aldehydes, thus providing the first one-pot synthesis of important tetrahydrofuran derivatives from four components. When bulky aldehydes were used, hydrolysis of the above reaction mixtures afforded 2-hexen-1,6-diols, which could be quantitatively transformed to their corresponding tetrahydrofuran derivatives when treated with stronger aqueous acid (12 N HCl).     

Zeolite nanocrystals inside mesoporous TUD-1: a high-performance catalytic composite

A hierarchically structured composite material with interconnecting meso- and micropores has been developed with the aim to optimize zeolite performance. A general synthetic method has been developed that, in a controlled manner, allows for various types of nanosized zeolite to be incorporated into a three-dimensional mesoporous matrix. Nanosized zeolite Beta was used to exemplify this new approach, resulting in a system in which zeolite Beta shows a higher cracking activity per gram of zeolite than pure nanosized zeolite Beta for the model feed n-hexane. Additionally, FTIR studies of CO and NH3 adsorption revealed that the nature of the acid sites in the nanozeolite has been partially modified due to the interactions with the mesoporous matrix, TUD-1.     

CuBr-catalyzed efficient alkynylation of sp3 C-H bonds adjacent to a nitrogen atom

A simple and effective catalytic method to construct propargylamine was developed by using copper bromide and tert-BuOOH via a combination of sp3 C-H bond and sp C-H bond activations followed by C-C bond formation.     

单耗分析案例

单耗分析案例宋之平,李洪涛（华北电力大学研究生部北京１０００８５）关键词能量系统,节能降耗,经济学１概述“单耗分析”以单耗为主要指标,以科学而直观的方式展示燃料单耗和成本的构成、分布和变化的图景以及影响因素,以便对改善设计、优化运行、促进管理科学化、...     

激光显微光谱法测定ITO导电膜中的Sn

本文利用激光显微光谱,涂片法制备样品,采用“Ｓ－Ｍ”法对ＩＴＯ导电膜中Ｓｎ进行定量分析,结果比较满意。     

Laser-induced breakdown spectroscopy based detection of lunar soil simulants for moon exploration

A scientific goal of the moon exploration project is to perform elemental analysis on the moon surface.The assuming of using laser-induced breakdown spectroscopy (LIBS) for this goal has been put forward.The laser plasma used by LIBS is sensitive to the surrounding atmosphere and the moon has very low ambient gas pressure on the surface, so the study of the LIBS capabilities at the low pressure was carried out.     

Dirichlet空间上的超循环复合算子

设Bn是复平面C中的单位圆盘(n=1)或复空间Cn中的单位球.众所周知,在Hardy空间上存在丰富的符号在Aut(Bn)中的超循环复合算子.然而,在复平面中单位圆盘上的Dirichlet空间中,任何复合算子都不能是超循环的.本文则证明,当n＞1时,Bn上的Dirichlet空间中确有超循环复合算子.