Beijing Electronic Science and Technology Vocational College

Beijing, China

Beijing Electronic Science and Technology Vocational College

Beijing, China
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Li H.-F.,Beijing Electronic Science and Technology Vocational College | Chang N.,Chinese People's Armed Police forces Academy | Chen X.-M.,Chinese People's Public Security University
Journal of China Universities of Posts and Telecommunications | Year: 2010

This paper studies the methods of image digital watermarking based on wavelet transform. Firstly, the characteristics of image digital watermarking as well as its processing procedure are introduced. On this basis, the discrete wavelet transform (DWT) is selected to achieve the embedding and distilling of image digital watermarking. Simulation test proves that this algorithm can embed or distill digital watermark effectively. Meanwhile it also proves that this watermark has better abilities of hiding and anti-interference. This method results in significant amount of computational savings as well. © 2010 The Journal of China Universities of Posts and Telecommunications.


Wu J.,Tsinghua University | Zhang C.,Tsinghua University | Mei X.,Tsinghua University | Li Y.,Tsinghua University | And 2 more authors.
Carbohydrate Polymers | Year: 2014

Enzymatic depolymerization of heparin by heparinases is promising for production of low molecular weight heparins (LMWHs) as anticoagulants, due to its mild reaction conditions and high selectivity. Here, different heparinase combinations were used to depolymerize heparin. Heparinase I and heparinase II can depolymerize heparin more efficiently than heparinase III, respectively, but heparinase III was the best able to protect the anticoagulant activities of LMWHs. Heparinase III and heparinase I/II combinations were able to efficiently depolymerize heparin to LMWHs with higher anticoagulant activity than the LMWHs produced by the respective heparinase I and heparinase II. HepIII and HepI is the best combination for maintaining high anti-IIa activity (75.7 ± 4.21 IU/mg) at the same Mw value. Furthermore, considering both the changes in molecular weight and anticoagulant activity, the action patterns of heparinase I and heparinase II were found not to follow the exolytic and processive depolymerizing mechanism from the reducing end of heparin. © 2013 Elsevier Ltd. All rights reserved.


PubMed | Tsinghua University, Beijing Electronic Science and Technology Vocational College and China Pharmaceutical University
Type: | Journal: Carbohydrate polymers | Year: 2016

Dermatan sulfate (DS) is one of the hardest impurities to remove from heparin products due to their high structural similarity. The development of a sensitive and feasible method for quantitative detection of DS in heparin is essential to ensure the clinical safety of heparin pharmaceuticals. In the current study, based on the substrate specificity of chondroitin B lyase, ultraviolet spectrophotometric and strong anion-exchange high-performance liquid chromatographic methods were established for detection of DS in heparin. The former method facilitated analysis in heparin with DS concentrations greater than 0.1mgmL(-1) at 232nm, with good linearity, precision and recovery. The latter method allowed sensitive and accurate detection of DS at concentrations lower than 0.1mgmL(-1), exhibiting good linearity, precision and recovery. The linear range of DS detection using the latter method was between 0.01 and 0.5mgmL(-1).


Qiu K.,Beijing Electronic Science and Technology Vocational College | Long Z.H.,Beijing Institute of Technology
Advanced Materials Research | Year: 2014

The performance of high strength steels is sensitive to the surface quality of machined surfaces. The effect of cutting condition on the variation of surface roughness in turning of 30CrMnSiA steel has been investigated through a serial of dry and oil-lubricant cutting tests. The characters of an amplitude characteristics set, Ra, Ry and tp, which are associated with the general shape of the machined surface profiles, are investigated in this study. It is concluded that, in the aspect of Ra and Ry values, dry cutting condition provides a similar surface roughness as in wet cutting condition under the experimental conditions of the present research; the bearing capacity of both kinds of machined surfaces, characterized by the bearing length rate tp, could be different according to the cutting parameters combinations. © (2014) Trans Tech Publications, Switzerland.


Qiu K.,Beijing Electronic Science and Technology Vocational College | Long Z.,Beijing Institute of Technology
Advanced Materials Research | Year: 2013

In order to improve the surface quality of ultra high strength low alloy steel work-pieces produced by high-speed face milling process, 23-1 factorial design experiment was con-ducted and the residual stress profiles within the surface and subsurface layer of work-pieces were measured. Corresponding empirical models for the residual stress profile were presented and the effects of cutting parameters (cutting velocity, feed per tooth, depth of cut) on characteristics of the residual stress profile were studied. Results show that: with the range of cutting parameters tested, the compressive residual stress profile would be induced below the work-pieces' surfaces machined by high speed face milling process. Feed per tooth has the critical influence on the characteristics of the compressive stress profile, and the mechanism of residual stress generation will be different when feed per tooth changes in high speed machining process. To obtain higher compressive stress and deeper compressive stress profile depth, larger feed rate and depth of cut are required. © (2013) Trans Tech Publications, Switzerland.


Qiu K.,Beijing Electronic Science and Technology Vocational College | Long Z.,Beijing Institute of Technology
Advanced Materials Research | Year: 2013

To investigate the nonlinear phenomena of cutting forces when machining difficult-to-machining materials in the high-speed cutting process, system experiments by factorial design and Latin hypercube sampling design were conducted. The cutting force nonlinear characteristics were analyzed in time domain and frequency domain through wave-let analysis and power spectrum analysis. Experiments indicated that in the high-speed milling process, the characteristic curves of primary cutting forces could not strictly maintain their linearity with the variation of cutting parameters, the effect of one cutting parameter on primary cutting forces is sensitive to the combination of cutting parameters, and a lower frequency periodic signal appears when the cutting speed is above 471 m/min (spindle speed is 3000 r/min). © (2013) Trans Tech Publications, Switzerland.


Zhou H.-J.,Beijing Electronic Science and Technology Vocational College | Wang M.-X.,Shaanxi University of Science and Technology | Zou W.,Siemens AG
Chung-kuo Tsao Chih/China Pulp and Paper | Year: 2015

In the PCS 7 system, which is the DCS platform of Siemens, a special control block MPC is offered for the small MIMO object, this block can realize the multi-variable model predictive control strategy. This paper introduced a solution to use MPC on air-cushioned headbox. The result of application proved that the integrated MPC block could control the air-cushioned headbox very well, even more the investment was very low compare with the stable control result. ©, 2015, China Technical Association of Paper Industry. All right reserved.


Pan L.,Beijing Electronic Science and Technology Vocational College | Guo J.,North China Institute of Science and Technology
Advances in Intelligent and Soft Computing | Year: 2012

Education of ideal faith is an essential part of ideological and political education for college students. It appears new characters and problems under the new historical conditions. Taking 528 college freshmen as an example to investigate and analyze ideal faith of contemporary college students in the new period. The result shows that in general the ideal faith of college students is good, but there are some problems with distinctive characteristics of times which should not be ignored. Ideal belief education for college students should be closely related to the reality of their lifestyle and thoughts. Pedagogue should follow the law of formation governing ideal belief, should be integrated into the process of college students' self-development, and should tend to deal with their problems as well. Realization of the social ideal, long-term ideal and lofty ideal should be integrated into the college students' individual ideal, short-term ideal and general ideal. © 2012 Springer-Verlag GmbH.


Yang P.,North China Electrical Power University | Hui D.X.,North China Electrical Power University | Kai Z.,North China Electrical Power University | Tian L.S.,Beijing Electronic Science and Technology Vocational College
Advanced Materials Research | Year: 2014

A path planning algorithm based on B-spline interpolation techniques was constructed for automatic welding system.The system used a B-spline curve to reconstruct the weld, it was achieved by reversing the control points of B-spline curve through the prescribed date points. The weld posture model was then obtained from the osculating plane and normal plane of B-spline curve. By taking a series coordinate transformation to the weld posture model, the torch posture model based on control terminal was provided.Experiments show that the new algorithm can readily be used for various three-dimensional welding tasks. © (2014) Trans Tech Publications, Switzerland.


Yang H.,Beijing Electronic Science and Technology Vocational College | Xuan L.,Zhejiang Institute of Communications
Journal of Networks | Year: 2014

Along with the widespread application of the electronic commerce in the modern business, the logistic distribution has become increasingly important. More and more enterprises recognize that the logistic distribution plays an important role in the process of production and sales. A good routing for logistic distribution can cut down transport cost and improve efficiency. In order to cut down transport cost and improve efficiency, a routing optimization based on taboo search for logistic distribution is proposed in this paper. Taboo search is a metaheuristic search method to perform local search used for logistic optimization. The taboo search is employed to accelerate convergence and the aspiration criterion is combined with the heuristics algorithm to solve routing optimization. Simulation experimental results demonstrate that the optimal routing in the logistic distribution can be quickly obtained by the taboo search algorithm. © 2014 ACADEMY PUBLISHER.

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