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Modeling and performance evaluation of the sleep mode in the IEEE 802.16e wireless networks with self-similar traffic

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The Journal of China Universities of Posts and Telecommunications 2009年第4期16卷 34-41页

作者： HUO zhan-qiang JIN Shun-fu TIAN Nai-shuo WANG Yan College of Information Science and Engineering Yanshan University Qinhuangdao 066004 China College of Science Yanshan University Qinhuangdao 066004 China School of Computer Science and Engineering Hebei University of Technology Tianjin 300401 China

IEEE 802.16e is currently the latest broadband wireless access standard designed to support mobility. In mobile networks, how to control energy consumption is one of the most important issues for battery-powered mobile stations. The standard proposes an energy saving mechanism named ＇sleep mode＇ for conserving the power of mobile stations. According to the operation principle of the sleep mode for downlink traffic in the type I power saving class, considering the self-similar nature of massive multimedia data in wireless networks, a discrete-time batch arrival Geom^x/G/1 queuing model with a close-down time and multiple vacations is built. The batch size is supposed to be Pareto distributed. By employing an embedded Markov chain method, the average queue length and the average sojourn time of the system model are derived. Correspondingly, the performance measures are obtained of the energy saving rate and the average packet delay time for the sleep mode in the IEEE 802.16e. The numerical results demonstrate the dependency relationships between the system performance measures and the system parameters with different offered loads and different self-similar degrees. Furthermore, a cost model is developed to determine the optimum length of the close-down time for minimizing the total system cost.

关键词： IEEE 802.16e sleep mode close-down self-similar energy saving rate

Effect of Coke Reaction Index on Reduction and Permeability of Ore Layer in Blast Furnace Lumpy Zone Under Non-Isothermal Condition

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Journal of Iron and Steel Research International 2013年第4期20卷 6-10页

作者： ZHAO Hong-bo bai Yong-qiang CHENG Shu-sen State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing China Metallurgical Industry Planning and Research Institute

Reasonable control on CRI（coke reaction index）is one of the key factors for BF（blast furnace）low-carbon ***,there are contrary *** is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in *** methods are adopted to realize effective catalysis（increasing CRI）and passivation（decreasing CRI）of *** tests of coke in BF lumpy zone under gradual temperature rising have been *** of CRI on gas composition,ore reduction,burden column permeability and heat reserve zone′s temperature under non-isothermal condition are *** combined with iron making calculations,a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.

关键词： blast furnace low carbon smelting resistance loss coke reaction index

Noncommutative Differential Calculus and Its Application on Discrete Spaces

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Communications in Theoretical Physics 2008年第1期49卷 37-44页

作者： LIU Zhen bai Yong-qiang WU Ke GUO Han-Ying Center of Mathematical Sciences Zhejiang University Hangzhou 310027 China Department of Mathematics Zhejiang University of Technology Hangzhou 310023China Institute of Mathematics Henan University Kaifeng 475001 China Department of Mathematics Capital Normal University Beijing 100037 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080China

We present the noncommutative differential calculus on the function space of the infinite set and construct a homotopy operator to prove the analogue of the Poincare lemma for the difference complex. Then the horizontal and vertical complexes are introduced with the total differential map and vertical exterior derivative. As the application of the differential calculus, we derive the schemes with the conservation of symplecticity and energy for Hamiltonian system and a two-dimensional integral models with infinite sequence of conserved currents. Then an Euler-Lagrange cohomology with symplectic structure-preserving is given in the discrete classical mechanics.

关键词： noncommutative differential calculus Poincare lemma horizontal and vertical complexes Euler-Lagrange cohomology

Staged reaction kinetics and characteristics of iron oxide direct reduction by carbon

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International Journal of Minerals,Metallurgy and Materials 2015年第10期22卷 1025-1032页

作者： Ru-fei Wei Da-qiang Cang Ling-ling zhang Yuan-yuan bai School of Metallurgical and Ecological Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Civil and Environmental Engineering University of Science and Technology Beijing Key Laboratory of Electromagnetic Processing of Materials of the Ministry of Education Northeastern University

Staged reduction kinetics and characteristics of iron oxide direct reduction by carbon were studied in this work. The characteristics were investigated by simultaneous thermogravimetric analysis, X-ray diffraction（XRD）, and quadrupole mass spectrometry. The kinetics parameters of the reduction stages were obtained by isoconversional（model-free） methods. Three stages in the reduction are Fe2O3→Fe3O4, Fe3O4→Fe O, and Fe O→Fe, which start at 912 K, 1255 K, and 1397 K, respectively. The CO content in the evolved gas is lower than the CO2content in the Fe2O3→Fe3O4stage but is substantially greater than the CO2 contents in the Fe3O4→Fe O and Fe O→Fe stages, where gasification starts at approximately 1205 K. The activation energy（E） of the three stages are 126–309 k J/mol, 628 k J/mol, and 648 k J/mol, respectively. The restrictive step of the total reduction is Fe O→Fe. If the rate of the total reduction is to be improved, the rate of the Fe O→Fe reduction should be improved first. The activation energy of the first stage is much lower than those of the latter two stages because of carbon gasification. Carbon gasification and FexOy reduction by CO, which are the restrictive step in the last two stages, require further study.

关键词： iron oxides direct reduction reduction kinetics re

In-situ stabilisation followed by ex-situ composting for treatment and disposal of heavy metals polluted sediments

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Journal of Environmental Sciences 2009年第7期21卷 877-883页

作者： YU Guangwei LEI Hengyi bai Tao LI Zhong YU qiang SONG Xianqiang School of Environmental Science and Engineering Sun Yat-sen University Guangzhou 510275 China Department of Environmental Science and Engineering South China Agriculture University Guangzhou 510642 China

An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows：（1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.

关键词： contaminated sediments treatment and disposal heavy metal in-situ stabilisation resource utilisation

Linear Arboricity of Regular Digraphs

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Acta Mathematica Sinica,English Series 2017年第4期33卷 501-508页

作者： Wei Hua HE Hao LI Yan Dong bai qiang SUN Department of Applied Mathematics Guangdong University of TechnologyGuangzhou 510006P.R.China Laboratoire de Recherche en Informatique UMR 8623C.N.R.S.-Universitg de Paris-sud91405-Orsay cedexFrance

A linear directed forest is a directed graph in which every component is a directed *** linear arboricity la(D) of a digraph D is the minimum number of linear directed forests in D whose union covers all arcs of D. For every d-regular digraph D, Nakayama and P′eroche conjecture that la(D) = d + 1. In this paper, we consider the linear arboricity for complete symmetric digraphs,regular digraphs with high directed girth and random regular digraphs and we improve some wellknown results. Moreover, we propose a more precise conjecture about the linear arboricity for regular digraphs.

关键词： Linear arboricity digraph Lovász Local Lemma random regular digraphs

A High-Efficiency Inversion Method for the Material Parameters of an Alberich-Type Sound Absorption Coating Based on a Deep Learning Model

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Computer Modeling in Engineering & Sciences 2022年第6期131卷 1693-1716页

作者： Yiping Sun Jiadui Chen qiang bai Xuefeng Zhao Meng Tao School of Mechanical Engineering Guizhou UniversityGuiyang550025China Aviation Academy Guizhou Open UniversityGuiyang550023China

Research on the acoustic performance of an anechoic coating composed of cavities in a viscoelastic material has recently become an area of great *** forward research methods are unable to manipulate sound waves accurately and effectively,are difficult to analyse,have time-consuming solution processes,and have large optimization search *** address these issues,this paper proposes a deep learning-based inverse research method to efficiently invert the material parameters of Alberich-type sound absorption coatings and rapidly predict their acoustic ***,an autoencoder(AE)model is pretrained to reconstruct the viscoelastic material parameters of an Alberich-type sound absorption coating,the material parameters are extracted into the latent feature space by the encoder,and the decoder model is *** internal relationship between the reflection coefficient and latent feature space is trained to establish a multilayer perceptron(MLP).Then,the reflection coefficients in the test set are input to the trained MLP and decoder models to automatically invert the material *** accuracy of the inversion result is 95.08%.Finally,a predictive model is trained to rapidly predict the acoustic performance of the inverted material *** speed of a single test target is 80 times faster than that of the finite element method(FEM).Furthermore,sound absorber material parameters with the best sound absorption performance and a three-band sound absorber are inverted,and their actual sound absorption performance is predicted by the proposed *** proposed deep learning-based inversion research method provides a solution for low-frequency,wide-band,strong attenuation,and precisely controlled sound *** achieves an efficient inversion of material parameters and the rapid forecasting of acoustic *** training model can be used for a sound absorbing coating composed of irregular cavities in a viscoelastic material and p

关键词： Anechoic coating deep learning inversion research rapid forecasting

Insight into the catalytic activity of MXenes for hydrogen evolution reaction

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Science Bulletin 2018年第21期63卷 1397-1403页

作者： Xiaowan bai Chongyi Ling Li Shi Yixin Ouyang qiang Li Jinlan Wang School of Physics Southeast University

MXenes have exhibited great potential as cost-effective electrocatalysts for hydrogen evolution reaction(HER). However, insight into the origin of activity is still missing. Herein, on the basis of a systematical investigation of the HER performance of 20 MXenes(M_2NO_2 and M_2CO_2, M = Sc, Ti, V, Cr, Zr, Nb, Mo,Hf, Ta and W), a Fermi-abundance model is proposed to understand variation of the activity in different MXenes. It is found that the occupied p electronic states of surface O atoms play a decisive role in the HER activity of MXenes. More importantly, Ti_2NO_2 and Nb_2NO_2 are found to be promising HER electrocatalysts with the free energy for hydrogen adsorption close to zero. This work not only provides possible catalysts for HER, the developed Fermi-abundance model but also is applicable to other two-dimensional materials and may serve as a simple descriptor of the intrinsic HER activity.

关键词： Two-dimensional materials MXenes Hydrogen evolution reaction Fermi-abundance model Density functional theory

Control of Beam Halo-Chaos for an Intense Charged-Particle Beam Propagating Through Double Periodic Focusing Field by Soliton

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Communications in Theoretical Physics 2008年第10期50卷 913-918页

作者： bai Long zhanG Rong WENG Jia-qiang FANG Jin-Qing College of Science China University of Mining and Technology Xuzhou 221008 China College of Physics and Electronic Technology Guangxi Normal University Guilin 541004 China China Institute of Atomic Energy Beijing 102413 China

We study an intense beam propagating through the double periodic focusing channel by the particle-coremodel,and obtain the beam envelope *** to the Poincare-Lyapunov theorem,we analyze the stabilityof beam envelope equation and find the beam *** soliton control method for controlling the beam halo-chaos isput forward based on mechanism of halo formation and strategy of controlling beam halo-chaos,and we also prove thevalidity of the control method,and furthermore,the feasible experimental project is *** perform multiparticlesimulation to control the halo by using the soliton *** is shown that our control method is *** alsofind the radial ion density changes when the ion beam is in the channel,not only the halo-chaos and its regeneration canbe eliminated by using the nonlinear control method,but also the density uniformity can be found at beam's centre aslong as an appropriate control method is chosen.

关键词： double periodic focusing channel beam envelope equation soliton controller radial ion density