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Particuology 2015年第2期13卷 53-59页

作者： Miao Miao Xin Feng Gangling Wang Shaomei Cao Wen Shi Liyi Shi Nano Science and Technology Research Center Shanghai University

Calcium sulfate hemihydrate （CSH） whiskers were synthesized by phase transition in CaCl2 solution under atmospheric pressure. Analytical-grade calcium sulfate dihydrate （AR CSD） was used as the raw material for the synthesis of CSH whiskers, according to orthogonal experiments. The effects of reaction tem- perature, AR CSD content, H2SO4 content, and reaction time were investigated, and the crystallization conditions were optimized. The as-prepared CSH whiskers displayed a regular morphology and a highly uniform size, with an aspect ratio of 105, A simulation system was also established by blending various sulfates with AR CSD, to evaluate the effects of impurities in flue gas desulfurization （FGD） gypsum. The main aim was to prepare CSH whiskers directly from FGD gypsum, without any purification, using the optimized conditions. This is a facile potential alternative process for large-scale production of CSH whiskers using abundant FGD gypsum as source materials.

关键词： FGD gypsum Calcium sulfate Whisker Direct transformation simulation analysis

Evaluation of conflict-resolution policies on controller taskload

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Chinese Journal of Aeronautics 2021年第5期34卷 315-330页

作者： Adan Ernesto VELA William SINGHOSE Karen FEIGH John-Paul CLARKE Eric FERON Department of Industrial Engineering and Management System University of Central FloridaOrlandoFL 32816USA George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA Daniel Guggenheim School of Aerospace Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

In an effort to maintain safety while satisfying growing air traffic demand,air navigation service providers are considering the inclusion of advisory systems to identify potential conflicts and propose resolution commands for the air traffic controller to verify and issue to *** understand the potential workload implications of introducing advisory conflict-detection and resolution tools,this paper examines a metric of controller taskload:how many resolution commands an air traffic controller issues under the guidance of an advisory *** a simulation study,the research presented here evaluates how the underlying protocol of a conflict-resolution tool affects the controller taskload(system demands)associated with the conflict-resolution process,and implicitly the controller workload(physical and psychological demands).Ultimately,evidence indicates that there is significant flexibility in the design of conflict-resolution algorithms supporting an advisory system.

关键词： Air traffic control Air traffic management Conflict detection and resolution Decision-support tools simulation analysis

Design and analysis of a truss deployable antenna mechanism based on a 3UU-3URU unit

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Chinese Journal of Aeronautics 2019年第12期32卷 2743-2754页

作者： Yundou XU Jinwei GUO Luyao GUO Wenlan LIU Jiantao YAO Yongsheng ZHAO Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China

Space deployable structures with large calibers, high accuracy, and large folding ratios are indispensable equipment in the aerospace field. Given that the single-DOF 3 RR-3 RRR deployable unit cannot be fully folded, this study proposes a 3 UU-3 URU deployable unit with two kinds of DOF: folding movement and orientation adjustment. First, based on the G-K formula, the DOF of the 3 UU-3 URU unit is analyzed. Then, the 3 UU-3 URU unit is used to construct a deployable truss antenna with a curved surface, and the DOF of the whole deployable antenna containing multiple 3 UU-3 URU units is calculated. The structural design of a deployable antenna with two loops is carried out with specific parameters and geometric relations. Next, a DOF simulation of a basic combination unit composed of three 3 UU-3 URU units is performed. Finally, a prototype of the basic combination unit is manufactured, and the DOF of the mechanism is experimentally verified.

关键词： Basic combination unit Degree of freedom(DOF) Deployable truss antenna simulation analysis Structural design

Methods for determining unimpeded aircraft taxiing time and evaluating airport taxiing performance

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Chinese Journal of Aeronautics 2017年第2期30卷 523-537页

作者： Yu Zhang Qing Wang Civil and Environmental Engineering University of South Florida College of Air Traffic Management Civil Aviation University of China College of Transportation Engineer Tongji University

The objective of this study is to improve the methods of determining unimpeded（nominal） taxiing time,which is the reference time used for estimating taxiing delay,a widely accepted performance indicator of airport surface *** reviewing existing methods used widely by different air navigation service providers（ANSP）,new methods relying on computer software and statistical tools,and econometrics regression models are *** models are highly recommended because they require less detailed data and can serve the needs of general performance analysis of airport surface *** proposed econometrics model outperforms existing ones by introducing more explanatory variables,especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration,ground delay program,and weather *** length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out *** proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.

关键词： Aircraft taxiing Airport performance Econometric regression modeling Queue length simulation analysis Taxiway system

Flow-field analysis of a continuous gas-solid separation fluidized bed equipped with a moving scraper

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Particuology 2021年第4期19卷 45-55页

作者： Bo Lv Xiaowei Deng Chaojun Fang Xiangnan Zhu College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuo 454000China Henan Key Laboratory for Green and Efficient Mining&Comprehensive Utilization of Mineral Resources Henan Polytechnic UniversityJiaozuo 454000China School of Chemical&Environmental Engineering Shandong University of Science&TechnologyQingdao 266590China

Continuous gas-solid separation fluidized beds are one of the most widely used practical operation units for the dry separation of coal in China,particularly in Northwest China,and they can effectively promote the efficient and clean utilization of raw *** a continuous gas-solid separation fluidized bed,the bed flow field is the concrete manifestation of the fluidization ***,the complexity of the flow field increases under the action of a moving *** this study,a combination of computational fluid dynamics(CFD)simulations and experimental measurements was used to study the changes in the flow field of a fluidized *** results showed that when the scraper moved,the local flow field(mainly characterized by the movement of medium particles)near the scraper was affected not only by the common airflow or bubbles,but also by the lateral driving force of the *** the scraper speed was v_(l)<6.0 cm/s,it reduced the frequency of the formation of large bubbles and alleviated the random fluctuation of the nearby particle collision stress signals,which improved the fluidization stability of the ***,the movement of the scraper affected the global flow *** flow field shifted to the right near the scraper,with the direction of the scraper movement,while the flow field exhibited a leftward trend on the surface of the bed,accompanied by some vortices,in the middle and lower parts of the ***,the critical height of the area,directly affected by the scraper,increased from 52 to 54 mm with an increase in its operating speed from v_(l)=2.96 cm/s to v_(l)=4.44 cm/s,*** provides a theoretical basis for further understanding the hydrodynamic characteristics of fluidized beds.

关键词： simulation analysis Moving scraper Flow-field Particle collision pressure Hydrodynamic characteristics

Na-doping-induced modification of the Cu_(2)ZnSn(S,Se)_(4)/CdS heterojunction towards efficient solar cells

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Journal of Energy Chemistry 2021年第6期30卷 618-626,I0015页

作者： Yali Sun Hongling Guo Pengfei Qiu Shengli Zhang Siyu Wang Li Wu Jianping Ao Yi Zhang Institute of Photoelectronic Thin Film Devices and Technology and Tianjin Key Laboratory of Thin Film Devices and Technology Nankai UniversityTianjin 300350China College of Physics Science and Technology Hebei UniversityBaoding 071002HebeiChina The MOE Key Laboratory of Weak-Light Nonlinear Photonics School of PhysicsNankai UniversityTianjin 300071China

It is very important to understand why a small amount of alkali metal doping in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells can improve the conversion *** this work,Na-doped CZTSSe is prepared by a simple solution method,and then the effects on the surface properties of the absorber layer,the buffer layer growth,and the modifications of the solar cell performance induced by the Na doping are *** surface of the absorber layer is more Cu-depletion and less roughness due to the Na *** addition,the contact angle of the surface increases because of Na *** a consequence,the thickness of the CdS buffer layer is significantly reduced and the optical losses in the CdS buffer layer are *** difference of quasi-Fermi levels(EFn-EFp) increases with a small amount of Na doping in the CZTSSe solar cell,so that open circuit voltage(VOC) increased *** work offers new insights into the effects of Na doping on CZTSSe via a solution-based approach and provides a deeper understanding of the origin of the efficiency improvement of Na-doped CZTSSe thin film solar cells.

关键词： Cu_(2)ZnSn(S,Se)_(4)solar cells Na doping Heterojunction Contact angles simulation analysis

Assessment and analysis of Carrying Capacity of 350 km/h EMUs Operating on Beijing-Shanghai Highspeed Railway

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Chinese Railways 2022年第2期 39-49页

作者： QU Siyuan SHI Junquan XU Ruihua Transport Department China Railway Shanghai Group Co Ltd. Collaborative Innovation Center on High-speed Rail Safety of Ministry of Education Nanjing Institute of Railway Technology College of Transportation Engineering Tongji University

This paper makes an analysis of the impact on the structure of the corridortype train working diagram by increasing the 350 km/h train pairs of Beijing-Shanghai High-speed Railway(HSR).According to the requirements of operation speed diversity,the multi-station receiving characteristics of cross-line trains and different train stopping schemes,this paper proposes a scheme of adding 350 km/h train pairs via computer analysis of carrying capability *** scheme is divided into three stages:(1)Initial stage:It is planned to increase trains running at 350 km/h,with 15~26 pairs of trains put into operation;(2)Rapid increase stage:27~142 pairs of 350 km/h trains are put into operation;(3)Full replacement stage:143~195 pairs of 350 km/h trains are put into operation,during which the number of cross-line trains under operation is controlled,the number of cross-line trains in each section is determined,the operation and connection scheme of cross-line trains is adjusted and the train stopping scheme is *** results of this study were used for the adjustment of the train working diagram in the third quarter of June 25,2021 to increase the number of 350 km/h train pairs from 19 to 30 on Beijing-Shanghai HSR.350 km/h trains are evenly arranged during 7:00—19:00 on the train working diagram and 300 km/h trains are arranged by making full use of every time and space,to improve the travelling speed on Beijing-Shanghai HSR as a whole.

关键词： Beijing-Shanghai HSR 350 km/h EMU train operation scheme train operation diagram carrying capacity assessment simulation analysis

The predicted effects of climate change on local species distributions around Beijing,China

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Journal of Forestry Research 2020年第5期31卷 1539-1550页

作者： Lichun Mo Jiakai Liu Hui Zhang Yi Xie School of Economies and Management Beijing Forestry UniversityBeijingPeople’s Republic of China School of Nature Conservation Beijing Forestry UniversityBeijingPeople’s Republic of China

To assist conservationists and policymakers in managing and protecting forests in Beijing from the effects of climate change,this study predicts changes for 2012–2112 in habitable areas of three tree species—Betula platyphylla,Quercus palustris,Platycladus orientalis,plus other mixed broadleaf species—in Beijing using a classification and regression tree niche model under the International Panel on Climate Change’s A2 and B2 emissions scenarios(SRES).The results show that climate change will increase annual average temperatures in the Beijing area by 2.0–4.7℃,and annual precipitation by 4.7–8.5 mm,depending on the emissions scenario *** changes result in shifts in the range of each of the *** suitable areas for distributions of *** and *** will decrease in the *** model points to significant shifts in the distributions of these species,withdrawing from their current ranges and pushing southward towards central *** of the ranges decline during the initial 2012–2040 period before shifting southward and ending up larger overall at the end of the 88-year *** mixed broadleaf forests expand their ranges *** *** forests,on the other hand,expand their range *** results indicate that climate change and its effects will accelerate significantly in Beijing over the next 88 *** stress is likely to be a major limiting factor on the distribution of forests and the most important factor affecting migration of species into and out of existing nature *** is a potential for the extinction of some ***,long-term vegetation monitoring and warning systems will be needed to protect local species from habitat loss and genetic swamping of native species by hybrids.

关键词： Climate change Classification and regression tree Plant distribution Scenario A2 and B2 simulation analysis

An in-depth review of theory of the TOPSIS method:An experimental analysis

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Journal of Management Analytics 2020年第2期7卷 281-300页

作者： Yakup Celikbilek Fatih Tuysuz Department of Management Information Systems Istanbul Gelisim UniversityIstanbulTurkey Department of Industrial Engineering Istanbul University-CerrahpaşaIstanbulTurkey

Decision-making is an important part of daily and business life for both individuals and *** the multi-criteria decision-making methods provide decision makers the necessary tools,they have differences in terms of the assumptions and fundamental ***,selecting the right decision-making method is at least as important as making the ***(Technique for Order Performance by Similarity to Ideal Solution)method,which is one of the most widely used multi-criteria decision-making methods,has gained attention of researchers and thus various improved versions of the method have been *** study considers the conventional TOPSIS method and experimentally displays the underlying reasons of the lacks of the conventional TOPSIS method by using a simulation *** experimental analysis based on simulation with an application is used to reveal theoretical fundamentals of the TOPSIS method to better understand it and contribute to its improvement.

关键词： TOPSIS Multiple criteria analysis simulation analysis Euclidean distance n-dimensionality

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

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International Journal of Agricultural and Biological Engineering 2021年第1期14卷 172-177页

作者： Xiaoqiang Du Tengfei Shen Lijun Zhao Guofeng Zhang Anguo Hu Shenggao Fang Yongqing Cao Xiaohua Yao School of Mechanical Engineering&Automation Zhejiang Sci-Tech UniversityHangzhou 310018China Zhejiang Province Key Laboratory of Transplanting Equipment and Technology Hangzhou 310018China College of Intelligent and Manufacturing Engineering Chongqing University of Arts and SciencesChongqing 402160China Yongkang Valid Technology Co. Ltd.Yongkang 321300ZhejiangChina Dongfanghong Forest Farm Jinhua 321000ZhejiangChina Research Institute of Subtropical Forestry Chinese Academy of ForestryHangzhou 311400China

Oil-tea camellia tree is an important oil plant in China that has long flexible *** most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow *** order to improve the harvesting efficiency and avoid damaging the flower bud,a hand-held fruit harvesting machine with a variable spacing comb brush was *** harvesting machine can generate three kinds of actuation to detach fruit when it *** main actuation results from the brushing of multiple comb *** other two kinds of actuation result from the beating of comb fingers on the fruits and the *** finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting ***,when the finger spacing is smaller than the diameter of the oil-tea fruit,the fruit is brushed off,but the flower bud and leaf pass through the finger *** the finger spacing is bigger than the fruit diameter,the fruit stuck between the fingers is loosened to ensure the continuous operation of the *** was used as the material of the brush finger to avoid damage,which can also reduce the overall *** dynamic simulation of the harvesting machine was carried out with ADAMS,and the acceleration of the front end of the comb finger and the variation of the finger spacing were *** prototype of the harvesting machine was built and tested in the *** experiment results showed that when the speed of the comb finger drive shaft was 480 r/min,the average harvesting percentage of oil-tea fruit was 80%,and the flower bud was seldom detached,which met the working requirements of oil-tea fruit harvesting.

关键词： oil-tea camellia fruit harvesting machine variable spacing comb brush simulation analysis