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He Z.,Harbin Institute of Technology | Wang G.-X.,Harbin Institute of Technology | Meng F.-W.,Northeast University at Qinhuangdao Campus
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2015

A new design method for nonlinear H∞ control was proposed. Though sum of squares (SOS) method can be used to solve analytically unsolvable nonlinear problems, but it still cannot be used directly to solve the Hamilton-Jacobi-Issacs (HJI) inequality or the nonlinear bounded-real inequality. The restrictions of the SOS method were discussed in detail. An iterative design procedure for nonlinear H∞ control problems was presented. There are two steps in each round of iteration. The first step is to design the nonlinear state feedback with adjustable gain matrix by using the SOS method. The second step is to solve an optimal problem in computation of the L2-gain by using a graphical-analytical method. A nonlinear H∞ control design for large attitude maneuvers of statellites was presented as an application example of the proposed method. ©, 2014, Editorial Department of Electric Machines and Control. All right reserved. Source

Yan T.,Yanshan University | Yu E.,Yanshan University | Zhao Y.,Northeast University at Qinhuangdao Campus
Materials and Design | Year: 2013

The hot deformation behavior of 55SiMnMo bainite steel was studied through isothermal hot compression tests conducted using a Gleeble 3500 at 950-1100°C, with strain rates of 0.01s-1 to 10s-1. A constitutive equation was established using the experimental results to describe the stress-strain relationship based on the dislocation density variation, considering the influence of the dynamic softening mechanism. When dynamic recovery is the only softening mechanism, a constitutive equation for flow stress was obtained from the variation of the dislocation density during hot deformation based on work hardening and dynamic recovery. When dynamic recrystallization occurs, the relationship between the dislocation density and the volume fraction of dynamic recrystallization was used to predict the flow stress after the peak. The reliability of the model was verified through a comparison between the predicted flow stress curves from the model and the experimental data. © 2013 Elsevier Ltd. Source

Wang G.,Northeast University at Qinhuangdao Campus
Applied Mechanics and Materials | Year: 2014

New urbanization is an important feature of China's development. The development of urbanization has a far-reaching effect on the building materials industries. The development of the building materials industries is closely interrelated with all of the national economy, and it is obviously affected by macro economy and investment in the fixed assets. In the national economy, building materials industries is an important basic one, and plays an important role in the course of the industrialization and urbanization of our country. Urbanization needs to speed up the upgrade of the building materials industries transition, and come true the new Chinese-style industry. In the building materials industries, there are still many problems, such as Low-level competition, high pressure in eliminating the backward, and so on. The building materials industries provide an important material foundation to fixed assets investment of the urbanization. © (2014) Trans Tech Publications, Switzerland. Source

Zhang M.,China University of Mining and Technology | Li G.,Northeast University at Qinhuangdao Campus | Mu H.L.,Dalian University of Technology | Ning Y.D.,Dalian University of Technology
Energy | Year: 2011

This paper aims at analyzing energy and exergy efficiencies in the Chinese transportation sector. Historical data is used to investigate the development of efficiencies from 1980 to 2009. Firstly, we calculate energy consumption values in PJ (petajoule) for nine transportation modes of five transportation sub-sectors. Then, the weighted energy and exergy efficiencies for each transportation mode, calculated by multiplying weighting factors with efficiency values of that mode, are summed up to calculate the weighted mean overall efficiencies for a particular year. We find that: (1) In 2009, the energy consumed in transportation sector was 12179.80 PJ, whereas that was 589.25 PJ in 1980. (2) Highways transport was the biggest energy consumer, which consumed 82.0% of total transport energy consumption in 2009. (3) Up to 2009, the oil consumed by transportation accounted for 75.1% of that in the whole country, which is more than the net oil import. (4) The average overall energy and exergy efficiencies are found to be 21.22% and 19.95%, respectively. (5) A comparison with other countries showed that energy and exergy efficiencies of the Chinese transportation sector are slightly lower than those of Jordan, Malaysian, Saudi Arabian and Norwegian, and higher than that incurred in Turkish. © 2010 Elsevier Ltd. Source

Yuan H.,Northeast University at Qinhuangdao Campus | Wang D.,Shenyang University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

The paper present a new approach of calculating the shortest paths, the approach was named as SPM (the shortest paths' matrix). Compared to the past approaches, SPM introduced distances into a matrix and could show activity distances directly in elements of the matrix and improved efficiency. The definition, operating rules of SPM and others related to SPM were described in this paper. At the end, the approach was applied to practical processes, the shortest paths were found out quickly. The approach provided a new resolution to the calculation of the shortest paths. © 2010 Springer-Verlag. Source

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