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On the Mathematical Nature of Wireless Broadcast Trees

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Tsinghua Science and Technology 2018年第3期23卷 223-232页

作者： Fulu Li Junwei Cao chunfeng wang Kui Wu Research Instituteof Information Technology Tsinghua University Beijing100084 China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094 China. Department of Computer Science University of Victoria BC VBW3P6 Canada.

Trees are arguably one of the most important data structures widely used in information theory and computing science. Different numbers of intermediate nodes in wireless broadcast trees may exert great impacts on the energy consumption of individual nodes, which are typically equipped with a limited power supply in a wireless sensor network; this limitation may eventually determine how long the given wireless sensor network can last. Thus, obtaining a deep understanding of the mathematical nature of wireless broadcast trees is of great importance. In this paper, we give new proof of Cayley＇s well-known theorem for counting labeled trees. A distinct feature of this proof is that we purely use combinatorial structures instead of constructing a bijection between two kinds of labeled trees, which is in contrast to all existing proofs. Another contribution of this work is the presentation of a new theorem on trees based on the number of intermediate nodes in the tree. To the best of our knowledge,this work is the first to present a tree enumeration theorem based on the number of intermediate nodes in the tree.

关键词： energy efficiency tree theorem broadcast trees wireless transmissions

Modelling the spreading rate of controlled communicable epidemics through an entropy-based thermodynamic model

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Science China(Physics,Mechanics & Astronomy) 2013年第11期56卷 2143-2150页

作者： wang WenBin WU ZiNiu wang chunfeng HU RuiFeng Department of Engineering Mechanics Tsinghua University School of Electro-Mechanical Engineering Xidian University

A model based on a thermodynamic approach is proposed for predicting the dynamics of communicable epidemics assumed to be governed by controlling eforts of multiple scales so that an entropy is associated with the *** the epidemic details are factored into a single and time-dependent coefcient,the functional form of this coefcient is found through four constraints,including notably the existence of an inflexion point and a *** model is solved to give a log-normal distribution for the spread rate,for which a Shannon entropy can be *** only parameter,that characterizes the width of the distribution function,is uniquely determined through maximizing the rate of entropy *** entropy-based thermodynamic(EBT)model predicts the number of hospitalized cases with a reasonable accuracy for SARS in the year *** EBT model can be of use for potential epidemics such as avian influenza and H7N9 in China.

关键词： epidemics entropy inflexion point

Cetyltrimethylammonium Bromide（CTAB）-Ionic Liquid Composite Modified Electrode for Sensitive Cyclic Voltammetric Determination of Bisphenol A

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Chemical Research in Chinese Universities 2016年第6期32卷 992-995页

作者： LIU Lihong wang chunfeng ZHUO Kelei Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of EducationSchool of Chemistry and Chemical Engineering Henan Normal University Xinxiang 453007 P. R. China

A sensitive electrochemical sensor for determining bisphenol A（BPA） was designed. The sensor was aglassy carbon electrode modified with the surfactant cetyltrimethylammonium bromide and the ionic liquid1-decyl-3-methylimidazolium tetrafluoroborate. The ability of the new sensor to measure BPA was investigated incyclic voltanmletry experiments. Under optimized conditions, the sensor gave a linear response range for BPA of2.19×10^-7 -3.28× 10^-5 mol/L and a detection limit of 7.31×10^8 mol/L（S/N=3） BPA could be determined with a lowerdetection limit, a wider linear range, and more sensitivity using the sensor than using other electrochemical sensors orhigh performance liquid chromatography with UV detection. The new sensor was used to determine BPA in tap waterwith recoveries of 97.5%--98.7% and a relative standard deviation 〈2.9%. The results show that the sensor can beused to determine trace BPA concentrations in tap water.

关键词： Bisphenol A Ionic liquid Surfactant Electrochemical sensor

Assessment of leaching behavior and human bioaccessibility of rare earth elements in typical hospital waste incineration ash in China

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Frontiers of Environmental Science & Engineering 2017年第6期11卷 35-45页

作者： chunfeng wang Guanfei Chen Yanchen Zhu Dan Yao Wanfeng wang Lianjun wang Henan Key Laboratory for Environmental Pollution Control and Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control Ministry of Education School of Environment Henan Normal University Xinxiang 453007 China Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse School of Environmental and Biological Engineering Nanjing University of Science and Technology Nanjing 210094 China

Leaching behavior and gastrointestinal bioaccessibility of rare earth elements （REEs） from hospital waste incineration （HWI） fly and bottom ash samples collected from Beijing and Nanjing Cities were assessed. In the same ash sample, the leaching concentrations of individual REEs determined by the Toxicity Characteristic Leaching Procedure （TCLP） were higher than those detected by the European standard protocol （EN-type test）, thereby suggesting that the low pH value of leaching solution was an important factor influencing the leacha（bility-of REE. The REE bioaccessibility results, which were evaluated using the physiologically based extraction test （PBET）, indicated that REEs were highly absorbed during fgastric phase by dissolution; and subsequently precipitated and/or re-adsorbed in small intestinal phase. The relative amounts of the total REEs extracted by the TCLP method, EN-type test and PBET test were compared. In addition to the pH value of extraction solutions, the chelating role of REEs witllt organic ligands used in the PBET method was also an important parameter affecting REE adsorption in human body. Additionally, this study showed that REEs were extracted by these methods as concomitants of heavy metals and anions （NO3^-, F^-, SO4^2- , and Cl^-） from HWI ash, which probably caused the remarkably complex toxicity on human body by the exposure pathway.

关键词： Assessment Rare earth elements Leaching behavior Bioaccessibility Hospital waste

Assessing human bioaccessibility of trace contaminants in size-fractionated red mud, derived precipitates and geopolymeric blocks

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Frontiers of Environmental Science & Engineering 2017年第6期11卷 109-118页

作者： chunfeng wang Yanchen Zhu Dan Yao Guanfei Chen Lianjun wang Henan Key Laboratory for Environmental Pollution Control and Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control Ministry of Education School of Environment Henan Normal University Xinxiang 453007 China Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse School of Environmental and Biological Engineering Nanjing University of Science and Technology Nanjing 210094 China

The objective of this study was to provide insight into hwnan exposure to trace contaminants bearing red mud, derived precipitates and geopolymeric blocks due to inhalation contact and/or hand-to-mouth ingestion. The in vitro bioaccessibility behavior of trace contaminants was investigated with the PBET （Physiologically based extraction test）, ALF （artificial lysosomal fluid） and MGS （modified Gamble＇ solution） methods. The results showed that total contents of trace contaminants and operation parameters, such as pH and chelating properties of simulated gastrointestinal phases （PBET）, played a joint role in controlling the bioaccessibility efficacy for size-fractionated red mud particles. As for airborne particles （〈 38 μm size fractions）, trace contaminants concentrations extracted by MGS was significantly higher than those by ALF. Additionally, higher bioaccessibility （PBET） values ofCu, Pb, Zn, As, V and U were obtained from red mud derived precipitates compared with those of red mud itself. Even though short-term and long-term leaching values of trace contaminants were relatively lower in the prepared geopolymeric blocks, the health risk could be significantly higher due to the more pronounced bioaccessibility characteristics.

关键词： Bioaccessibility Trace contaminants Red mud Precipitates Geopolymeric blocks

Design and realization of threshold secret sharing scheme with random weights

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Journal of Systems Engineering and Electronics 2009年第5期20卷 1091-1095页

作者： Ye Zhenjun Fang Zhenming wang chunfeng Meng Fanzhen Dept. of Mathematics and Physics North China Electric Power Univ. Beijing 102206 P. R. China School of Management Tianjin Univ. Tianjin 300072 P. R. China School of Science Tianjin Univ. Tianjin 300072 P. R. China

A new threshold secret sharing scheme is constructed by introducing the concept of share vector, in which the number of shareholders can be adjusted by randomly changing the weights of them. This kind of scheme overcomes the limitation of the static weighted secret sharing schemes that cannot change the weights in the process of carrying out and the deficiency of low efficiency of the ordinary dynamic weighted sharing schemes for its resending process. Thus, this scheme is more suitable to the case that the number of shareholders needs to be changed randomly during the scheme is carrying out.

关键词： random weight secret sharing share vector.

Bayesian network learning algorithm based on unconstrained optimization and ant colony optimization

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Journal of Systems Engineering and Electronics 2012年第5期23卷 784-790页

作者： chunfeng wang Sanyang Liu Mingmin Zhu Department of Mathematical Sciences Xidian University Xi'an 710071 E R. China Department of Mathematics Henan Normal University Xinxiang 453007 E R. China

Structure learning of Bayesian networks is a wellresearched but computationally hard *** learning Bayesian networks,this paper proposes an improved algorithm based on unconstrained optimization and ant colony optimization（U-ACO-B） to solve the drawbacks of the ant colony optimization（ACO-B）.In this algorithm,firstly,an unconstrained optimization problem is solved to obtain an undirected skeleton,and then the ACO algorithm is used to orientate the edges,thus returning the final *** the experimental part of the paper,we compare the performance of the proposed algorithm with ACO-B *** experimental results show that our method is effective and greatly enhance convergence speed than ACO-B algorithm.

关键词： Bayesian network structure learning ant colony optimization unconstrained optimization

Enhanced remediation of Cr(Ⅵ)-contaminated groundwater by coupling electrokinetics with ZVI/Fe_(3)O_(4)/AC-based permeable reactive barrier

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Journal of Environmental Sciences 2022年第2期34卷 280-290页

作者： Ruolin Cao Shiqing Liu Xinyu Yang chunfeng wang Yanbin wang Wanfeng wang Yunqing Pi Henan Key Laboratory for Environmental Pollution Control and Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control(Ministry of Education) School of EnvironmentHenan Normal UniversityXinxiang 453007China

Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron *** a solution,a synergistic system with PRB and electrokinetics(PRB-EK)was established and applied for the efficient removal of Cr(Ⅵ)-contaminated *** the filling material of PRB,ZVI/Fe_(3)O_(4)/activated carbon(ZVI/Fe_(3)O_(4)/AC)composites were synthesized by ball milling and thermal treatment.A series of continuous flow column experiments and batch tests was conducted to evaluate the removal efficiency of Cr(Ⅵ).Results showed that the removal efficiency of Cr(Ⅵ)remained above 93%even when the bed volume(BV)reached 2000 under the operational parameters(iron/AC mass ratio,2:1;current,5 m A).The mechanism of Cr(Ⅵ)removal by the PRB-EK system was revealed through field emission scanning electron microscopy images,X-ray diffraction,X-ray photoelectron spectroscopy,Fe^(2+) concentration,and redox potential(E h)*** key in Cr(Ⅵ)reduction was the Fe^(2+)/Fe^(3+) cycle driven by the surface microelectrolysis of the *** application of an externally supplied weak direct current maintained the redox process by enhancing the electron transfer capability of the system,thereby prolonging the column ***(Ⅵ)chemical speciation was determined through sequential extraction,verifying the stability and safety of the *** findings provide a scientific basis for PRB design and the in-situ remediation of Cr(Ⅵ)-contaminated groundwater.

关键词： ZVI/Fe_(3)O_(4)/AC Electrokinetics Micro-electrolysis Cr(Ⅵ)-continuous ground water Zero-valent iron

Co-modulated interface binding energy and electric field distribution of layer-structured PVDF–LDPE dielectric composites with BaTiO3: experiment and multiscale simulations

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Frontiers of Materials Science 2023年第3期17卷 155-167页

作者： Ruitian Bo chunfeng wang Yongliang wang Peigang He Zhidong Han School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150040China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Engineering Dielectrics and Its Application(Ministry of Education) Harbin University of Science and TechnologyHarbin 150080China

The layer-structured composites were built by the dielectric and insulating layers composed of polyvinylidene fluoride(PVDF)and low-density polyethylene(LDPE)composites containing barium titanate(BT)to modulate the dielectric and energy storage properties of the *** simulations on the interface models for molecular dynamics and the geometric models for finite element analysis were performed together with the experimental characterization of the morphology,dielectric,and energy storage properties of the *** results revealed that polyethylene as an insulating layer played a successful role in modulating dielectric permittivity and breakdown strength while BT particles exerted positive effects in improving the miscibility between the composed layers and redistributing the electric *** strong interface binding energy and the similar dielectric permittivity between the PVDF layer and the BT20/LDPE layer made for the layer-structured composites with a characteristic breakdown strength(Eb)of 188.9 kV·mm^(−1),a discharge energy density(Ud)of 1.42 J·cm^(−3),and a dielectric loss factor(tanδ)of 0.017,which were increased by 94%,141%,and decreased by 54%in comparison with those of the BT20/PVDF composite,respectively.

关键词： dielectric composite layer structure low-density polyethylene polyvinylidene fluoride molecular dynamics simulation finite element analysis

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