Zhou F.,Quzhou University
The Scientific World Journal | Year: 2014
We study the local convergence properties of inexact Newton-Gauss method for singular systems of equations. Unified estimates of radius of convergence balls for one kind of singular systems of equations with constant rank derivatives are obtained. Application to the Smale point estimate theory is provided and some important known results are extended and/or improved. © 2014 Fangqin Zhou.
Zhang Y.,Quzhou University
Engineering Transactions | Year: 2015
Electromigration (EM) in solder joints under high current density has become a critical reliability issue for the future high density microelectronic packaging. A practical method of atomic density integral (ADI) for predicting solder bump electromigration reliability is proposed in this paper. The driving forces in electromigration include electron wind force, stress gradient, temperature gradient as well as atomic density gradient. The electromigration simulation is performed on flip chip ball grid array (FCBGA) package based on ADI method, and the simulation results for void generation and time to failure (TTF) have a reasonably good correlation with the testing results. Orthogonal experimental design has been used to evaluate the effect of design parameters on TTF of electromigration. Based on this study, some practical recommendations are made to optimize the package design and improve the solder bump electromigration reliability. © 2015, Polish Academy of Sciences. All rights reserved.
Hu L.,Quzhou University
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao | Year: 2016
The integration of computer network and foreign language teaching is quite different from computer-assisted instruction in essence: Computer-assisted instruction focuses on assistant function, namely, assisting teachers to improve the teaching effect; while the integration of computer and teaching becomes an organic component of the whole teaching system. The paper carries out a discussion from following aspects based on investigations and surveys on a large number of literatures: Through the sound function of "individuation" feature emphasized by Web2.0 computer network environment in terms of the teaching mode: (such as Blog, Wiki, etc.), the communication between teachers and students as well as among students is promoted to a higher level so as to realize the innovation and share of knowledge. The application of computer network environment interaction technology based on Web2.0 into English language teaching mode can construct a kind of new interactive teaching mode between teachers and students.
Lyu C.,Quzhou University
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2014
Reasonable choice of rock strength criteria is crucial for stress and displacement prediction and support design in tunnel engineering. Based on Mogi-Coulomb strength criterion and elastic-perfectly plastic model, analytical solutions of stress and displacement for surrounding rocks around a circular tunnel were derived The intermediate principal stress coefficient was used to present the intermediate principal stress effect. The results in this study were compared with the current solutions in the literatures and the influence of intermediate principal stress and shear strength parameters of surrounding rocks was discussed. The results showed extensive applicability and the Mohr-Coulomb strength criterion and Matsuoka-Nakai criterion are two special cases; when the intermediate principal stress coefficient b was equals to 0.5, the results indicated that the intermediate principal stress effect and its range for rock strength; the influence of cohesion and internal friction angle on the plastic radius and tunnel wall displacement was significant; Care should be taken to the effects of intermediate principal stress and shear strength parameter variations of surrounding rocks on tunnel design and construction.
Yu Z.,Zhejiang University of Technology |
Lv Y.,Zhejiang University of Technology |
Lv Y.,Quzhou University |
Yu C.,Zhejiang University of Technology
Organic Process Research and Development | Year: 2012
An expeditious and multikilogram-scale process for the Balz-Schiemann synthesis of o-difluorobenzene from ofluoroaniline via two separate continuous flow reactors in 90.0% yield has been set up. The main steps involved the generation of stable diazonium fluoborate intermediate in situ via continuous diazotization reactor at 20 °C, and the choice of odifluorobenzene as cosolvent to achieve the continuous flow fluorodediazoniation system. Reaction time of both steps could be brought down to within 10 s and 2 min, respectively, by increasing the reaction temperature and thereby taking advantage of improved mass and heat American Chemical Society. © 2012 American Chemical Society.