Beijing Technology and Business University

english.btbu.edu.cn/
Beijing, China

Beijing Technology and Business University , BTBU, is a public comprehensive university in Beijing, China. It was founded based on the amalgamation of Beijing Light Industry School , Beijing Business School and the Administration School for Ministry of Machinery Industry. Wikipedia.


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Gao Y.,Peking University | Gao Y.,Beijing Technology and Business University | Wang L.,Peking University
IEEE Transactions on Automatic Control | Year: 2011

This technical note studies consensus problems of multiple agents with continuous-time second-order dynamics, where each agent can obtain its positions and velocities relative to its neighbors only at sampling instants. It is assumed that the sampling period of each agent is independent of the others' and the interaction topology among agents is time-varying, where the associated direct graphs may not have spanning trees. If the union graph of all direct graphs has a spanning tree, then there exist controller gains and sampling periods such that consensus is reached. Moreover, two approaches are presented to design such controller gains and sampling periods. Simulations are performed to validate the theoretical results. © 2011 IEEE.


Feng F.,Beijing Technology and Business University | Qian L.,Beijing Technology and Business University
Polymer Composites | Year: 2014

A series of flame-retardant rigid polyurethane foams (RPUFs) containing dimethyl methylphosphonate (DMMP) and expandable graphite (EG) were prepared by box-foaming. The RPUFs were characterized by thermogravimetric analysis (TGA), the limiting oxygen index (LOI), cone calorimeter, and scanning electron microscope (SEM). The decomposition process of DMMP was investigated by Pyrolysis-Gas Chromatography/Mass Spectroscopy (Py-GC/MS). Accordingly, their flame retardant behaviors and mechanism were also discussed. The results show that the DMMP/EG system can linearly enhance the LOI value from 19.2% of the pure RPUF to 33.0% of RPUFs containing 16 wt% flame retardant. In addition, the DMMP/EG system also remarkably increases yields of the residual char and drastically decreases the peak value of heat release rate (PHRR), heat release rate (HRR), total heat release (THR), total smoke release (TSR), and the yields of CO (COY). In the flame retardant RPUFs, when the matrix is ignited, the flame retardant DMMP should be decomposed to gaseous PO2 fragments, which can inhibit free radical chain reaction of flammable alkyl free radical from the decomposed matrix; whereas the flame retardant EG can rapidly expand and form loose and worm-like expanding graphite char layer accordingly, which can hinder the heat transmission to the inner matrix and reduce decomposing velocity of matrix. After the combination of the two flame retardant effects, the DMMP/EG flame retardant system provides the matrix with better flame retardant effects than one of them does. Namely, it shows excellent gas-condensed bi-phase synergistic effect. POLYM. COMPOS., 35:301-309, 2014. © 2013 Society of Plastics Engineers.


He P.-S.,Beijing Technology and Business University
European Physical Journal D | Year: 2013

In this paper, we prove analytically that the plane-wave Bose-Einstein condensates with spin-orbit coupling are stable in two dimensions at zero temperature. The SOC induced extra breaking of the O(2) symmetry of the ground state makes the goldstone modes more divergent in the infrared limit. But the depletions are still finite, which means the condensates are stable. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Li Y.,Beijing Technology and Business University
Advances in Applied Mathematics and Mechanics | Year: 2014

In this paper, we revisit a priori error analysis of nonconforming finite element methods for the Poisson problem. Based on some techniques developed in the context of the a posteriori error analysis, under two reasonable assumptions on the nonconforming finite element spaces, we prove that, up to some oscillation terms, the consistency error can be bounded by the approximation error. We check these two assumptions for the most used lower order nonconforming finite element methods. Compared with the classical error analysis of the nonconforming finite element method, the a priori analysis herein only needs the H1 regularity of the exact solution. © 2014 Global Science Press.


Zhang L.,Nankai University | Yu H.,Nankai University | Wang P.,Beijing Technology and Business University
Bioresource Technology | Year: 2013

With the aim to develop an ecologically viable catalytic pathway for furfural production without the use of inorganic acids, H3PW12O40, Amberlyst-5 and NKC-9 (macroporous styrene-based sulfonic acid resin) were used as catalysts for producing furfural from xylose, xylan and lignocellulosic biomass in [BMIM]Cl under microwave irradiation at atmospheric pressure. A surprisingly high furfural yield of 93.7% from xylan was obtained by H3PW12O40 at 160°C in 10min. The degradation of furfural affected by single addition of [BMIM]Cl and solid acids was also investigated. The IL could be easily recycled and reused with stable solvent capacity for multiple runs (5×) after the product furfural was extracted with ethyl acetate. © 2013 Elsevier Ltd.


Sun J.,Beijing Technology and Business University | Cui D.,Beijing Technology and Business University
Journal of the American Ceramic Society | Year: 2014

Dy3+-activated Na3YSi2O7 phosphors have been prepared via a solid-state reaction technique and may be used as a component of white light-emitting diodes. X-ray diffraction analysis demonstrates the single-phase formation and the substitution of activator ions for Na3YSi2O7:Dy3+ materials. The emission of Dy3+ in different Y3+ lattice sites exhibits blue (4F9/2→6H15/2) and yellow (4F9/2→6H13/2) lights, which function together to generate white light. The optimum doping concentration is 3 mol% and energy transfer between Dy3+ ions has been validated to be a resonant type via an electric dipole-dipole mechanism. The temperature-dependent luminescent properties from 25°C to 400°C are studied, and the blue emission increases as a function of the temperature. This interesting phenomenon is proposed to be the result of the model in the configurational coordination diagram. The present investigation reveals the potential application for Na3YSi2O7:Dy 3+ system in solid-state lighting. © 2013 The American Ceramic Society.


Wang M.,Beijing Technology and Business University | Wang Q.,Henan Institute of Science and Technology | Zhang B.,East Carolina University
Gene | Year: 2013

MicroRNAs (miRNAs) are an important gene regulator, controlling almost all biological and metabolic processes, in both plants and animals. In this study, we investigated the effect of drought and salinity stress on the expression of miRNAs and their targets in cotton (Gossypium hirsutum L.). Our results show that the expression change of miRNAs and their targets were dose-dependent and tissue-dependent under salinity and drought conditions. The expression of miRNAs in leaf was down-regulated under higher salinity stress while shows variable patterns in other conditions. The highest fold-changes of miRNAs were miR398 in roots with 28.9 fold down-regulation under 0.25% NaCl treatment and miR395 in leaves with 7.6 fold down-regulation under 1% PEG treatment. The highest up-regulation of miRNA targets was AST in roots with 4.7 fold-change under 2.5% PEG and the gene with highest down-regulation was CUC1 in leaves with 25.6 fold-change under 0.25% NaCl treatment. Among seven miRNA-target pairs we studied, five pairs, miR156-SPL2, miR162-DCL1, miR159-TCP3, miR395-APS1 and miR396-GRF1, show significant regulation relationship in roots and leaves under salinity stress concentration. © 2013 Elsevier B.V.


Li Y.,Beijing Technology and Business University
Advances in Applied Mathematics and Mechanics | Year: 2011

In this paper, we analyze the Wilson element method of the eigenvalue problem in arbitrary dimensions by combining a new technique recently developed in [10] and the a posteriori error result. We prove that the discrete eigenvalues are smaller than the exact ones. © 2011 Global Science Press.


Mo L.,Beijing Technology and Business University | Jia Y.,Beihang University
IET Control Theory and Applications | Year: 2011

This study is devoted to the consensus problems for high-order multi-agent systems with external disturbances. A dynamic neighbour-based protocol is adopted for the agents with the consideration of communication time delay and external disturbances. Sufficient conditions are derived to make all agents reach consensus with H∞ performance. Finally, simulation results are provided for demonstrating the effectiveness of the results presented. © 2011 The Institution of Engineering and Technology.


Gao J.,Beijing Technology and Business University
Applied Mechanics and Materials | Year: 2013

Location based service is one of the main application of mobile internet. The combination of traditional community business and mobile internet is the location-based business mode of online to offline. This article tries to analyze the mode from four aspects: the strategic positioning, open platform, marketing mode and profit mode. Location-based mobile application, such as, Mobile phone map, wechat, automated check-in, etc., may add customers to the community stores, but also challenge their service. © (2013) Trans Tech Publications, Switzerland.

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