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Discrete element method study of solid descending and residence properties in COREX shaft furnace with center gas supply device

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Journal of Iron and Steel Research International 2019年第7期26卷 669-678页

作者： Heng Zhou Qin-fu Hou Ming-yin Kou Shun Yao Sheng-li Wu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Department of Chemical Engineering Monash University Clayton VIC 3800 Australia

Solid descending and residence properties in COREX shaft furnace with a center gas supply device (CGSD) were studied using the discrete element method. Solid flow pattern, residence time distribution, and local solid residence time (SRT) were analyzed. Moreover, the effects of the rotation speed of screws, the radius, and height of CGSD were investigated. The results show that the solid flow is dominantly a plug flow in the shaft furnace with the CGSD. In the upper region of the shaft furnace for gas-solid reduction, uniform distribution of local SRT is observed, which is preferable to match the even gas distribution expected due to the CGSD and slots. For different rotation speeds of the screws, the distribution of solid flow patterns is similar. The averaged residence time, dispersed plug volume fraction, and dead volume fraction decrease with increasing the rotation speed of the screws. The radius of the CGSD affects the solid residence in the shaft furnace. Local SRT above the CGSD increases with the increase in the radius of CGSD, possibly leading to the formation of more agglomerates. Hence, the radius of CGSD should be chosen carefully. The height of CGSD has a minor effect on solid residence in the shaft furnace.

关键词： COREX shaft furnace Solid residence time Discrete element method Center gas supply device Solid descending

The Effect of Money-Back Guarantee and Customer Value on Dual-Channel supply Chain

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Journal of Systems Science and Systems Engineering 2019年第5期28卷 636-654页

作者： Limin Wang Qiankun Song Zhenjiang Zhao School of Economics and Management Chongqing Jiaotong University Chongqing 400074 China Department of Mathematics Chongqing Jiaotong University Chongqing 400074 China Department of Mathematics Huzhou University Huzhou 313000 China

This paper investigates the effect of money-back guarantee (MBG) and customer value on dualchannel supply *** could produce and sell old generation product by direct channel to compete with new generation product by retail *** retailer and manufacturer could choose whether implementing the MBG strategy or *** paper discusses whether manufacturer should open the direct channel,how to make MBG strategy to realize maximum profits,and how customer value influences the supply *** give the boundary conditions of four situations about the decisions of retailer and manufacturer GG situation,GN situation,NG situation and NN *** find that MBG strategy by retailer brings higher retail unit price,MBG strategy by manufacturer brings higher direct unit price and influences the wholesale price by the net salvage value of new generation *** paper shows that if the demand was positive,opening the direct channel always benefits the ***,customer value affects demands of two channels and the threshold value of parameter is given in this paper.

关键词： Money-back guarantee customer value dual-channel supply chain product choice

A review on chemical oxygen supply technology within confined spaces: Challenges, strategies, and opportunities toward chemical oxygen generators(COGs)

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International Journal of Minerals,Metallurgy and Materials 2019年第8期26卷 925-937页

作者： Jian-guo Liu Long-zhe Jin Na Gao Sheng-nan Ou Shu Wang Wei-xiang Wang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines of the Ministry of Education University of Science and Technology BeijingBeijing 100083China Mine Emergency Technology Research Center University of Science and Technology BeijingBeijing 100083China

Chemical oxygen generators(COGs)have been used worldwide in confined spaces as an emergency oxygen supply technology,mainly because they are independent and have a long shelf ***,a number of challenges related to COGs remain unsolved,and a literature review of the current state of the technology is ***,the present article summarizes the basic information and applications of COGs,including their oxygen production mechanism,components,forming technology,and ignition *** current challenges encountered in applying COGs are discussed,along with the strategies adopted thus far to solve these problems,as found in the published *** literature survey reveals that,although much effort has been devoted to controlling the oxygen production rate and the heat output of COGs,the mechanism of producing toxic gases remains unclear and a reliable and safe ignition system has not been fully ***,future opportunities in the development of COGs are briefly listed.

关键词： chemical oxygen generators oxygen supply technology thermal decomposition catalytic metal fuel combustion

Will Germany move into a situation with unsecured power supply?

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Frontiers in Energy 2019年第3期13卷 551-570页

作者： Harald SCHWARZ Energy Distribution and High Voltage Engineering Faculty 3Brandenburg University of TechnologyCottbus-Senftenberg 03013Germany

Together with a huge number of other countries, Germany signed the Paris Agreements in 2015 to prevent global temperature increase above 2℃. Within this agreement, all countries defined their own national contributions to CO2 reduction. Since that, it was visible that CO2 emissions in Germany decreased, but not so fast than proposed in this German nationally determined contribution to the Paris Agreement. Due to increasing traffic, CO2 emissions from this mobility sector increased and CO2 emission from German power generation is nearly constant for the past 20 years, even a renewable generation capacity of 112 GW was built up in 2017, which is much higher than the peak load of 84 GW in Germany. That is why the German National Government has implemented a commission (often called "The German Coal Commission") to propose a time line: how Germany can move out of coal-fired power stations. This "Coal Commission" started its work in the late spring of 2018 and handed over its final report with 336 pages to the government on January 26th, 2019. Within this report the following proposals were made:①Until 2022: Due to a former decision of the German Government, the actual remaining nuclear power generation capacity of about 10 GW has to be switched off in 2022. Besides, the "Coal Commission" proposed to switch off additionally in total 12.5 GW of both, hard coal and lignite-fired power plants, so that Germany should reduce its conventional generation capacity by 22.5 GW in 2022.②Until 2030: Another 13 GW of German hard coal or lignite-fired power plants should be switched off.③Until 2038:The final 17 GW of German hard coal or lignitefired power plants should be switched off until 2038 latest. Unfortunately the "Coal Commission" has not investigated the relevant technical parameter to ensure a secured electric power supply, based on German's own national resources. Because German Energy Revolution mainly is based on wind energy and photovoltaic, this paper will describe the

关键词： CO2 reduction mobility sector renewable generation coal commission secured power generation capacity reliable power supply power-to-gas power-to-heat

Wholesale Pricing and Evolutionarily Stable Strategy in Duopoly supply Chains with Social Responsibility

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Journal of Systems Science and Systems Engineering 2019年第1期28卷 110-125页

作者： Caichun Chai Tiaojun Xiao Institute of Game Behavior and Operations Management School of Management Science and Engineering Nanjing University of Finance and Economics Nanjing 210023 China School of Management and Engineering Nanjing University Nanjing 210093 China

This paper analyzes manufacturers’ wholesale price decisions and the evolutionarily stable strategies of the retailers’ marketing behavior in duopoly supply chains, where each chain consists of one manufacturer and many retailers. Each retailer chooses one of two marketing strategies: social responsibility or non-social responsibility (i.e., a firm only cares about the benefits of its shareholders). We identify the conditions under which a strategy profile is evolutionarily stable. Furthermore, we investigate the manufacturers’ wholesale prices and find the following:(i) the retailer’s social responsibility decreases the unit wholesale price;(ii) when the degree of the retailer’s social responsibility is medium, the social responsibility of the retailer in a supply chain increases the profit of the retailer’s own manufacturer and decreases the profit of the rival’s manufacturer;otherwise, it decreases the profits of the two manufacturers;and (iii) when each retailer exhibits its social responsibility moderately, a triple-win situation can be achieved.

关键词： Evolutionarily stable strategy replicator dynamics social responsibility supply chain management

Efficiency optimized fuel supply strategy of aircraft engine based on air-fuel ratio control

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Chinese Journal of Aeronautics 2019年第2期32卷 489-498页

作者： Yixuan WANG Yan SHI Maolin CAI Weiqing XU Qihui YU School of Automation Science and Electrical Engineering Beihang University School of Mechanical Engineering Inner Mongolia University of Science & Technology

Accurate fuel injection control of aircraft engine can optimize the energy efficiency of UAV power system while meeting the propeller speed requirement. Traditional injection control method such as open-loop calibration causes instability of fuel supply which brings the risk of power loss of UAV. Considering that the closed-loop control of AFR can ensure a stable fuel feeding, this paper proposes an AFR control based fuel supply strategy in order to improve the efficiency of fuel-powered UAV while obtaining the required engine speed. According to the optimum fuel injection results, we implement fuzzy-PID method to control the set AFR in different situations. Through simulation and experiment studies, the results indicate that, to begin with, the calibrated mathematical model of the aircraft engine is effective. Next, this fuel supply strategy based on AFR control can normally realize the engine speed regulation, and the applied control algorithm can eliminate the overshoot of AFR throughout all the working progress. What is more,the fuel supply strategy can averagely shorten the response time of the engine speed by about two seconds. In addition, compared with the open-loop calibration, in this work the power efficiency is improved by 9% to 33%. Last but not the least, the endurance can be improved by 30 min with a normal engine speed. This paper can be a reference for the optimization of UAV aircraft engine.

关键词： AFR control Aircraft engines Efficiency optimization Fuel supply strategy Simulation and experiments

Design and control of the accelerator grid power supply-conversion system applied to CFETR N-NBI prototype

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Plasma Science and Technology 2020年第8期22卷 175-183页

作者： Dongyu WANG Ming ZHANG Shaoxiang MA Shu YANG Kexun YU Yuan PAN State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074People's Republic of China School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhan 430074People's Republic of China

The acceleration grid power supply(AGPS)rated 200 kV/25 A is a key component devoted to supply the acceleration grids of the China fusion engineering test reactor negative-ion-based neutral beam injector(N-NBI)prototype *** paper focused on the design and control of the AGPS conversion system(AGPS-CS),with emphasis on the requirement of the wide range output voltage and rise time.A voltage regulation switch at the front of step-down transformer is applied to optimize the grid current and DC-link ***,a new feedforward control strategy with piecewise PI compensator is proposed to improve the characteristics of *** simulation results of the proposed AGPS-CS are presented,proving the performance of the power supply to achieve the desired requirements.

关键词： CFETR NBI accelerator grid power supply feedforward control high voltage power supply

MPC-Based Change Management of supply Chain Under Disruption Risks:The Case of Battery Industry

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IEEE/CAA Journal of Automatica Sinica 2023年第9期10卷 1896-1898页

作者： Yi Yang Chen Peng School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China IEEE

Dear Editor,The health management of battery supply chain(SC)is vital to battery-related *** letter focuses on the study of health management of battery SC under ***,a discrete-time model of battery SC is developed based on the actual industrial ***,a model predictive control-based change management(MPCCM)strategy is proposed to ensure stable manufacturing of ***,the effects of disruption are also considered in terms of the actual ***,the validity of the proposed strategy is verified by a case study in Dongsheng Electronics Co.,Ltd.

关键词： battery Battery supply

Optimum combination of water drainage, water supply and eco-environment protection in coal-accumulated basin of North China

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Science China Earth Sciences 2000年第2期43卷 122-131页

作者：武强董东林石占华武雄孙卫东叶责钧李树文刘金韬 1. Department of Geology China University of Mining and Technology 100083 Beijing China 2. Nanjing Mining Company Shanghai Meishan Group Company 210045 Nanjing China 3. Economic College of Shijiazhuang 050031 Shijiazhuang China 4. Chinese Bureau of Coal Geology 072700 Zhuozhou China

The conflict among water drainage, water supply and eco-environment protection is getting more and more serious due to the irrational drainage and exploitation of ground water resources in coal-accumulated basins of North China. Efficient solutions to the conflict are to maintain long-term dynamic balance between input and output of the ground water basins, and to try to improve resourcification of the mine water. All solutions must guarantee the eco-environment quality. This paper presents a new idea of optimum combination of water drainage, water supply and eco-environment protection so as to solve the problem of unstable mine water supply, which is caused by the changeable water drainage for the whole combination system. Both the management of hydraulic techniques and constraints in economy, society, ecology, environment, industrial structural adjustments and sustainable developments have been taken into account. Since the traditional and separate management of different departments of water drainage, water supply and eco-environment protection is broken up, these departments work together to avoid repeated geological survey and specific evaluation calculations so that large amount of national investment can be saved and precise calculation for the whole system can be obtained. In the light of the conflict of water drainage, water supply and eco-environment protection in a typical sector in Jiaozuo coal mine, a case study puts forward an optimum combination scheme, in which a maximum economic benefit objective is constrained by multiple factors. The scheme provides a very important scientific base for finding a sustainable development strategy.

关键词： combination system of water drainage water supply and eco-environment protection optimal combination resourcification of mine water.