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A case study of gas drainage to low permeability coal seam

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International Journal of Mining Science and Technology 2017年第4期27卷 687-692页

作者： Zhang Li Zhang Hui guo hao China Coal Strategies Research Center & China Center for Occupational Safety and Health Beijing 100713 China Institute of Public Safety Research/Department of Engineering Physics Tsinghua University Beijing 100084 China College of Resource and Safety Engineering China University of Mining & Technology Beijing 100083 China

Gas drainage at low gas permeability coal seam is a main barrier affecting safety and efficient production in coal mines. Therefore, the research and application of drainage technology at low permeability coal seam is a key factor for gas control of coal mine. In order to improve the drainage effect, this paper establishes a three-dimensional solid-gas-liquid coupling numerical model, and the gas drainage amounts of different schemes are examined inside the overburden material around the goaf. The Yangquan mine area is selected for the case study, and the gas movement regularity and emission characteristics are analyzed in detail, as well as the stress and fissure variation regularity. Also examinations are the released gas movement, enrichment range and movement regularity during coal extraction. Moreover, the gas drainage technology and drainage parameters for the current coal seam are studied. After measuring the gas drainage flow in-situ, it is concluded that the technology can achieve notable drainage results, with gas drainage rate increase by 30%–40% in a low permeability coal seam.

关键词： Gas drainage Low permeability Ground drilling holes Coupling model Abutment stress

Examining Inequality in the Public Health Workforce Distribution in the Centers for Disease Control and Prevention(CDCs) System in China, 2008–2017

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Biomedical and Environmental Sciences 2020年第5期33卷 374-383页

作者： LI Yuan Qiu CHEN hao guo hao Yan Office of Policy Research Chinese Center for Disease Control and PreventionBeijing 102206China National Immunization Program Chinese Center for Disease Control and PreventionBeijing 100050China The National Center for Chronic and Noncommunicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijing 100050China

Objective Allocation of human resources to address inequalities in the public health system has increasingly attracted societal and political *** the Centers for Disease Control and Prevention(CDCs)system of China as an example,we evaluated inequality in the public health workforce distribution across different regions in China between 2008 and 2017,with the aim of providing information for policymakers to support resource allocation and address growing health *** We used three standard public health workforce inequality indices-Gini coefficient,Theil L,and Theil T-and spatial autocorrelation analysis to explore spatial clusters of the workforce in different provinces,visualized with geographical *** The aggregate workforce-to-population ratio decreased from 1.47 to 1.42 per 10,000 population from 2008 to 2017,and was consistently lower than the National Health Commission’s(NHC)recommended critical shortage threshold of *** workforce distribution inequality indices varied by regional socioeconomic and health system *** clustering of CDCs workforce distribution was evident,with H–H and L–L clusters in western China and the Guangdong-Fujian region,*** Our study addressed key issues for government and policymakers in allocation of public health human *** is an urgent need for careful identification of analytic questions that will help carry out public health functions in the new era,alongside policy implications for an equitable distribution of the public health workforce focusing on the western region and low–low cluster areas.

关键词： Inequality Public health workforce CDCs Gini coefficient Geographical distribution

Phase composition, morphology and element contents of micro-arc oxidation ceramic coatings on Ti–6Al–4V alloy under different calcination conditions

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Rare Metals 2016年第11期35卷 836-840页

作者： guo-Dong hao Xue-long hao Zu-Fang Zhu Department of Chemistry Mudanjiang Normal University National Center of Analysis and Testing for Nonferrous Metals and Electronic Materials General Research Institute for Nonferrous Metals

Compound ceramic coatings with the main crystalline of Al_2TiO_5（in the as-prepared coating without treatment） were prepared in situ on the surface Ti-6Al-4V alloy by means of pulsed bipolar micro-arc oxidation in Na AlO_2 solution. For the purpose of studying the antioxidation properties of the samples, the coated samples treated in argon and the as-coated samples were calcined in air at 1000 °C. And the related characteristics were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and X-ray fluorescence（XRF） spectroscopy, respectively. The results show that, when it was calcined in air for 1 h, Al_2TiO_5in the as-prepared coating decomposed and transformed into α-Al_2O_3 and rutile TiO_***, after almost 4 h in argon, Al_2TiO_5in the asprepared coating decomposed and the final coating surface contents are completely α-Al_2O_3, and those of the middle interface are mainly Al_2O_3 and Ti_2O_3. The morphologies of the coatings after calcination in argon and air are ***-temperature oxidation occurred violently in the alloy substrate without coatings. Furthermore, the weight gain curves of the as-prepared samples and the coated samples treated in argon both show a parabolic shape.

关键词： Micro-arc oxidation Ti-6AI-4V Argon High-temperature oxidation

Gelcasting of 316L stainless steel

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Journal of University of Science and Technology Beijing 2007年第6期14卷 507-511页

作者： Yan Li Zhimeng guo Junjie hao Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

A novel near-net process, gelcasting, was successfully used to prepare larger size 316L stainless steel parts with complex shape. In this study, the effects of process parameters on the viscosity of the slurry and the dry green strength were investigated. The results show that gas atomization （GA） powder is more suitable for gelcasting compared with water atomization （WA） powder. The maximum solid loading is 55vo1% for ball-milled slurry with GA powders. And the optimum amounts of monomers （acrylamide （AM）＋methylenebisacrylamide （MBAM）; the mass ratio, 30：1） and initiator in the AM system are 1.8% （based on the weight of metal powder） and 0.8%-1.4% （based on the weight of monomers）, respectively, at which, the maximum green strength obtained is 33.7 MPa. The mechanical properties of the sintered specimen are as follows： ultimate tensile strength, 493 MPa; yield strength, 162 MPa; and HRB, 72.

关键词： gelcasting 316L stainless steel complex-shape slurry green strength

Subspace decomposition-based correlation matrix multiplication

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Journal of Systems Engineering and Electronics 2008年第2期19卷 241-245页

作者： Cheng hao guo Wei Yu Jingdong National Key Lab of Communication Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

The correlation matrix, which is widely used in eigenvalue decomposition （EVD） or singular value decomposition （SVD）, usually can be denoted by R = E[yiy＇i]. A novel method for constructing the correlation matrix R is proposed. The proposed algorithm can improve the resolving power of the signal eigenvalues and overcomes the shortcomings of the traditional subspace methods, which cannot be applied to low SNR. Then the proposed method is applied to the direct sequence spread spectrum （DSSS） signal＇s signature sequence estimation. The performance of the proposed algorithm is analyzed, and some illustrative simulation results are presented.

关键词： subspace theory correlation matrix eigenvalue decomposition direct sequence spread spectrum signal

Receiver Power Allocation and Transmitter Power Control Analysis for Multiple-Receiver Wireless Power Transfer Systems

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Journal of Electronic Science and Technology 2019年第4期17卷 291-299页

作者： Zhi-hao guo Shi-Er Dong the School of Civil Engineering and Geomatics Southwest Petroleum University

As different power has its own receivers,this paper analyzes and designs a multiple-receiver wireless power transfer(WPT)system *** equivalent circuit model of the system is established to analyze the key parameters including transmitter power,receiver power,transmission efficiency,and each receiver power allocation.A control circuit is proposed to achieve the maximum transmission efficiency and transmitter power control and arbitrary receiver power allocation ratios for different *** the proposed control circuit,receivers with different loads can allocate appropriate power according to its power demand,the transmitter power and system efficiency do not vary with the change of the number of ***,this control circuit is validated using a 130-kHz WPT system with three receivers whose power received is 3:10:12,and the overall system efficiency can reach as high as 55.5%.

关键词： Multiple-receiver receiver power allocation transmitter power control wireless power transfer(WPT).

Improving benzene catalytic oxidation on Ag/Co_(3)O_(4) by regulating the chemical states of Co and Ag

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Journal of Environmental Sciences 2024年第9期143卷 201-212页

作者： hao guo Tao guo Mengqi Zhao Yaxin Zhang Wenfeng Shangguan Yinnian Liao State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources Xinjiang UniversityXinjiang 830017China Xinjiang Key Laboratory of Coal Clean Conversion&Chemical Engineering Process Xinjiang UniversityXinjiang 830017China School of Chemical Engineering and Technology Xinjiang UniversityXinjiang 830017China Research Center for Combustion and Environmental Technology Shanghai Jiao Tong UniversityShanghai 200240China School of Applied Chemistry and Materials Zhuhai College of Science and TechnologyGuangdong 519041China

Silver(9 wt.%)was loaded on Co_(3)O_(4)-nanofiber using reduction and impregnation methods,*** to the stronger electronegativity of silver,the ratios of surface Co^(3+)/Co^(2+) on Ag/Co_(3)O_(4) were higher than on Co_(3)O_(4),which further led to more adsorbed oxygen species as a result of the charge ***,the introducing of silver also obviously improved the reducibility of Co_(3)O_(4).Hence the Ag/Co_(3)O_(4) showed better catalytic performance than Co_(3)O_(4) in benzene *** with the Ag/Co_(3)O_(4) synthesized via impregnation method,the one prepared using reduction method(named as Ag Co-R)exhibited higher contents of surface Co^(3+) and adsorbed oxygen species,stronger reducibility,as well as more active surface lattice oxygen ***,Ag Co-R showed lowest T_(90) value of 183℃,admirable catalytic stability,largest normalized reaction rate of1.36×10^(-4)mol/(h·m^(2))(150℃),and lowest apparent activation energy(E_(a))of 63.2 kJ/*** analyzing of in-situ DRIFTS indicated benzene molecules were successively oxidized to phenol,o-benzoquinone,small molecular intermediates,and finally to CO_(2) and water on the surface of Ag *** last,potential reaction pathways including five detailed steps were proposed.

关键词： Reduction method Co_(3)O_(4)-supported Ag catalyst,VOCs Benzene oxidation Reaction mechanism

Link Prediction in Brain Networks Based on a Hierarchical Random Graph Model

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Tsinghua Science and Technology 2015年第3期20卷 306-315页

作者： Yanli Yang hao guo Tian Tian Haifang Li School of Computer Science and Technology Taiyuan University of Technology

Link prediction attempts to estimate the likelihood of the existence of links between nodes based on available brain network information, such as node attributes and observed links. In response to the problem of the poor efficiency of general link prediction methods applied to brain networks, this paper proposes a hierarchical random graph model based on maximum likelihood estimation. This algorithm uses brain network data to create a hierarchical random graph model. Then, it samples the space of all possible dendrograms using a Markov-chain Monte Carlo algorithm. Finally, it calculates the average connection probability. It also employs an evaluation index. Comparing link prediction in a brain network with link prediction in three different networks （Treponemapallidum metabolic network, terrorist networks, and grassland species food webs） using the hierarchical random graph model, experimental results show that the algorithm applied to the brain network has the highest prediction accuracy in terms of AUC scores. With the increase of network scale, AUC scores of the brain network reach 0.8 before gradually leveling off. In addition, the results show AUC scores of various algorithms computed in networks of eight different scales in 28 normal people. They show that the HRG algorithm is far better than random prediction and the ACT global index, and slightly inferior to local indexes CN and LP. Although the HRG algorithm does not produce the best results, its forecast effect is obvious, and shows good time complexity.

关键词： brain network link prediction hierarchical random graph maximum likelihood estimation method

Corrosion Inhibition of Imidazoline Derivates with Benzene Rings on Mild Steel in CO_2-Saturated Brine Solution

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Chemical Research in Chinese Universities 2012年第4期28卷 691-695页

作者： CHEN guo-hao Zhao Jing-mao College of Materials Science and Engineering Beijing University of Chemical TechnologyBeijing 100029P.R.China

Corrosion inhibition of three imidazoline derivates with different numbers of benzene rings,namely 2-phenyl-1-ethylamino imidazoline（CI-1）,2-phenyl-1-ethylamino-1-methylbenzyl quaternary imidazoline（CI-12） and 2-phenyl-1-benzoyl ethylamino imidazoline（CI-13）,on mild steel in CO2-saturated brine solution was evaluated by mass-loss method and potentiodynamic polarization *** results show that the three imidazoline derivates can inhibit CO2 corrosion effectively with CI-12 ranking the *** mainly restrain the anodic dissolution and act as anodic-type *** adsorptions of these derivates on the mild steel surface follow the Langmuir adsorption isothermal equation and belong to chemical adsorption.

关键词： Corrosion inhibitor CO2 corrosion Langmuir adsorption Imidazoline derivate