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Journal of Thermal Science 2020年第4期29卷 972-981页

作者： wang zhipeng CHENG Shuhao ZHUO Yuqun Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Beijing Engineering Research Center for Ecological Restoration and Carbon Fixation of Saline–alkaline and Desert Land Tsinghua UniversityBeijing 100084China China Institute of Atomic Energy Beijing 102413China

The flow and heat transfer characteristics of Maxwell fluid in a pipe under pulsating pressure gradient were studied. The governing equations were made dimensionless. The Rubin boundary condition was adopted. The flow field was solved theoretically and the temperature field was obtained using finite volume method. A general model suitable for various fluctuating characteristics and physical parameters was established. The Deborah number(De) was used to characterize the fluidity of the fluid. The influence of De on flow and temperature fields was evaluated. The Nusselt number and start-up process of Maxwell fluid were studied. Results showed that the influence of De on flow field was greater than that on temperature field. The effect of De on Nusselt number was irregular and related to the oscillation parameters. The over-shooting amplitude and oscillation time of axis center velocity in start-up flow grow larger with De.

关键词： Maxwell fluid pulsating flow Hagen-Poiseuille law Deborah number start-up flow

An Improved Ionospheric Spatial Threat Model for SBAS

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Chinese Journal of Electronics 2017年第5期26卷 1105-1110页

作者： ZHANG Qidong LI Rui wang zhipeng School of Electronic and Information Engineering Beihang University

A conservative Grid ionospheric vertical delay error(GIVE) estimation would lead to conservative Protection levels(PLs) estimation and affects Satellitebased augmentation systems(SBAS) service *** reduce the margin in GIVE estimation,an improved spatial threat model is presented.A new parameter of Minimum separation distance(MSD) is *** new model is described with the MSD,Relative centroid metric(RCM) and fit radius as *** delay measurements during storms are used to construct the new spatial threat *** results show that,with the new model,there is at least 9.5% reduction in User ionospheric vertical delay errors(UIVEs),while the user ionospheric delay estimation errors can be bounded at the same *** on severe ionosphere disturbed days,at least 5% improvement of PLs(95%) could be achieved for more than20% Conterminous united states(CONUS) area,leading to higher system service performance.

关键词： Spatial threat model Grid ionospheric vertical delay error(GIVE) Minimum separation distance

A method for automatic detection and characterization of plasma bubbles using GPS and BDS data

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Chinese Journal of Aeronautics 2021年第5期34卷 195-204页

作者： Qiang LI Yanbo ZHU zhipeng wang Kun FANG National Key Laboratory of CNS/ATM School of Electronics and Information EngineeringBeihang UniversityBeijing 100191China Aviation Data Communication Corporation Beijing100191China

Detecting and characterizing Total Electron Content(TEC)depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble(EPB)when applying the Ground-Based Augmentation System(GBAS)at low *** paper develops a robust method to automatically identify TEC depletion and derive its *** rolling barrel algorithm is used to automatically identify the TEC depletion candidate and its ***,the depletion candidates are screened by several improved techniques to distinguish actual depletions from other phenomena such as Traveling Ionospheric Disturbance(TID)or abnormal ***,based on the depletion signals from three triangular receivers,the method derives EPB parameters such as velocity,width and *** time lag and front velocity are calculated based on crosscorrelation using TEC depletions and the geometrical distribution of three triangular *** width and gradient of slope are then determined by using TEC depletion from a single *** comparison,both the station-pair method and proposed method depend on the assumption that the EPB morphology is frozen during the short time when the plasma bubble moves between the ***,our method relaxes the restriction that the baseline length should be shorter than the width of slope required by the *** relaxation is favorable for studying small-scale slope of depletions using stations of a longer *** addition,the accuracy of the width and gradient is free of impact from hardware biases and small-scale disturbance,as it is based only on the relative TEC *** method is demonstrated by processing Global Positioning System(GPS)and Bei Dou Navigation Satellite System(BDS)data on 15 August,2018,in a solar minimum cycle.

关键词： Depletion drift Ground-Based Augmentation System(GBAS) Ionosphere gradient Plasma bubble TEC depletion

Correlation-weighted least squares residual algorithm for RAIM

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Chinese Journal of Aeronautics 2020年第5期33卷 1505-1516页

作者： Dan SONG Chuang SHI zhipeng wang Cheng wang Guifei JING School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Frontier Institute of Science and Technology Innovation Beihang UniversityBeijing 100191China

The Least Squares Residual(LSR)algorithm,one of the classical Receiver Autonomous Integrity Monitoring(RAIM)algorithms for Global Navigation Satellite System(GNSS),presents a high Missed Detection Risk(MDR)for a large-slope faulty satellite and a high False Alarm Risk(FAR)for a small-slope faulty *** the theoretical analysis of the high MDR and FAR cause,the optimal slope is determined,and thereby the optimal test statistic for fault detection is conceived,which can minimize the FAR with the MDR not exceeding its allowable *** construct a test statistic approximate to the optimal one,the CorrelationWeighted LSR(CW-LSR)algorithm is *** CW-LSR test statistic remains the sum of pseudorange residual squares,but the square for the most potentially faulty satellite,judged by correlation analysis between the pseudorange residual and observation error,is weighted with an optimal-slope-based *** does not obey the same distribution but has the same noncentral parameter with the optimal test *** superior performance of the CW-LSR algorithm is verified via simulation,both reducing the FAR for a small-slope faulty satellite with the MDR not exceeding its allowable value and reducing the MDR for a large-slope faulty satellite at the expense of FAR addition.

关键词： Correlation analysis Fault detection Least squares residual(LSR)algorithm Receiver autonomous integrity monitoring(RAIM) Slope

UAV image target localization method based on outlier filter and frame buffer

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Chinese Journal of Aeronautics 2024年第7期37卷 375-390页

作者： Yang wang Hongguang LI Xinjun LI zhipeng wang Baochang ZHANG Institute of Unmanned System Beihang UniversityBeijing 100191China School of Electronics and Information Engineering Beihang UniversityBeijing 100191China Institute of Artificial Intelligence Beihang UniversityBeijing 100191China

With rapid development of UAV technology,research on UAV image analysis has gained *** the existing techniques of UAV target localization often rely on additional equipment,a method of UAV target localization based on depth estimation has been ***,the unique perspective of UAVs poses challenges such as the significant field of view variations and the presence of dynamic objects in the *** a result,the existing methods of depth estimation and scale recovery cannot be directly applied to UAV ***,there is a scarcity of depth estimation datasets tailored for UAV perspectives,which makes supervised algorithms *** address these issues,an outlier filter is introduced to enhance the applicability of depth estimation networks to target localization.A frame buffer method is proposed to achieve more accurate scale recovery,so as to handle complex scene textures in UAV *** proposed method demonstrates a 14.29%improvement over the *** with the average recovery results from UAV perspectives,the difference is only 0.88%,approaching the performance of scale recovery using ground truth ***,to overcome the limited availability of traditional UAV depth datasets,a method for generating depth labels from video sequences is *** to state-of-the-art methods,the proposed approach achieves higher accuracy in depth estimation and stands for the first attempt at target localization using image *** algorithm and dataset are available at https://***/uav-tan/uav-object-localization.

关键词： Object localization Deep learning Depth estimate Scale recovery Unmanned Aerial Vehicle(UAV)

A flight experimental platform for synchrophasing control based on a small propeller UAV

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Science China(Technological Sciences) 2018年第12期61卷 1915-1924页

作者： CAO YunFei HUANG XiangHua SHENG Long wang zhipeng College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China JiangSu Province Key Laboratory of Aerospace Power System Nanjing 210016 China

Turboprop engine has the advantages of high efficiency and high thrust, but it has not been widely used in the civil field because of the noise excited by the low speed propellers. Propeller synchrophasing control is an active noise control method without increasing the weight of the airframe, which can attenuate the noise level in the cabin by controlling the relative phase among multiple propellers. It is generally accepted that altitude and airspeed have a great influence on the noise reduction effect of propeller synchrophasing, but there is no theoretical research about how these two factors affect the noise level. Therefore, flight experiment is considered to be a credible way. However, flight experiments of propeller synchrophasing control in turboprop aircraft have been accomplished in few countries due to enormous cost and inconvenience. An experimental platform of synchrophasing control based on a two-propeller small unmanned air vehicle(UAV) is proposed which can carry out the flight experiment research in a low-cost way. The phase angle sensor, the FOC-based scheme of motor driving, the all-slave synchrophasing control and the coordination between speed and phase difference control are presented in the UAV platform to meet its synchrophasing control precision requirement, experimental results prove that all of them can significantly enhance the performance of synchrophasing control. Noise characteristics of propellers are studied in the flight experiments, the noise predicted by the noise model is highly consistent with the actual measured noise, which verifies that the noise characteristics of small UAV accord with propeller signature theory. Based on the noise model, propeller synchrophasing has a steady effect to minimizing noise in the UAV platform. These show that the UAV platform is a feasible solution for propeller synchrophasing research.

关键词： propeller synchrophasing noise reduction small UAV flight experimental platform low cost

Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed Decomposition and Sequential Chemical Extraction

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Journal of Environmental Sciences 2016年第5期28卷 169-176页

作者： Zhenwu Zhu Yuqun Zhuo Yaming Fan zhipeng wang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University

A considerable amount of Hg is retained in flue gas desulfurization（FGD） gypsum from Wet Flue Gas Desulfurization（WFGD） systems. For this reason, it is important to determine the species of Hg in FGD gypsum not only to understand the mechanism of Hg removal by WFGD systems but also to determine the final fate of Hg when FGD gypsum is disposed. In this study, Temperature Programmed Decomposition（TPD） and Sequential Chemical Extraction（SCE） were applied to FGD gypsum to identify the Hg species in it. The FGD gypsum samples were collected from seven coal-fired power plants in China, with Hg concentrations ranging from 0.19 to 3.27 μg/g. A series of pure Hg compounds were used as reference materials in TPD experiments and the results revealed that the decomposition temperatures of different Hg compounds increase in the order of Hg_2Cl_2〈 HgCl_2〈 black HgS 〈 Hg_2SO_4〈 red HgS 〈 HgO 〈 HgSO_4. The Hg compounds existing in FGD gypsums identified by TPD included HgCl_2, Hg_2Cl_2, Hg_2SO_4, black HgS and red HgS, of which mercury sulfides were the primary compounds. The results of SCE indicated that Hg was mainly distributed in the strongly complexed phase. The low Hg content in FGD gypsum increases the ambiguity of assigning extraction fractions to certain Hg species by SCE. The fact that the primary compounds in FGD gypsum are HgS phases leads the leaching of Hg in the natural environment to be quite low, but a considerable amount of Hg may be released during the industrial heating process.

关键词： Mercury speciation FGD gypsum Thermal desorption Sequential Chemical Extraction

教师发展的行动意蕴与内涵——基于阿伦特行动理论的视角

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教师教育学报 2025年第1期12卷 38-46页

作者：王志鹏刘旭东西北师范大学教育科学学院甘肃兰州730070

教师发展强调教师作为具体而丰富的人的整体性发展,旨在促使教师教育重新聚焦教师生命本身。阿伦特的行动理论是立足于人的生命本身来理解行动的,并从自成目的、相互砥砺、主动探究三个维度阐明了行动的核心内涵,凸显了行动之于人的生... 详细信息

教师发展强调教师作为具体而丰富的人的整体性发展,旨在促使教师教育重新聚焦教师生命本身。阿伦特的行动理论是立足于人的生命本身来理解行动的,并从自成目的、相互砥砺、主动探究三个维度阐明了行动的核心内涵,凸显了行动之于人的生命成长的独特价值,为从生命本身出发来把握教师发展的行动意蕴提供了重要启示。彰显行动意蕴的教师发展是合乎教师精神本能的自成目的性的活动,也是与环境的改变相契合的相互砥砺的过程,还是构成日常教育生活不可或缺的主动探究活动。以往受工具理性教育思维、程序化教育模式以及现代性教育理论的制约,教师发展往往被视为日常教育生活之外的附加性活动,其行动意蕴被遮蔽。在当前教师教育追求高质量发展的时代背景下,需要重新发掘行动的意义,以推动教师发展回归日常教育生活。为此,要关注日常教育生活中的教师改变,展现教师发展的真实样态;加强日常教育生活中的人际交往和沟通,拓展教师发展的时空边界;聚焦日常教育生活中的问题解决,促进教师在教育研究中获得发展。

关键词：教师发展教师专业发展汉娜·阿伦特行动理论教师教育教师改变

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Simulation and analysis of soil homogenization drills based on discrete element method and response surface methodology

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Particuology 2024年第5期88卷 128-148页

作者： zhipeng wang Tong Zhu Youzhao wang Song Yang Feng Ma Xu Li Institute of Process Equipment and Environmental Engineering School of Mechanical Engineering and AutomationNortheastern UniversityShenyang110819China Liaoning Coning Testing Co. Ltd.Shenyang110170 China

Currently,rotary drilling is one of the main pieces of equipment used for in-situ remediation of contaminated ***,this equipment has problems such as uneven mixing and low utilization efficiency,which affect the efficiency of in-situ soil *** improve the efficiency of in-situ soil remediation,this paper takes contaminated black soil as the research object,and the structural design of the new three-stage soil remediation auger is carried out based on *** mixing process of soil and heavy metal passivator under different motion and structural parameters was investigated by the discrete element method(DEM)and response surface *** experimental design was based on rotational speed,homogenizing mixing time,crushing section pitch,and homogenizing section pitch as factors,and soil fragmentation ratio,the coefficient of dispersion,and torque as optimization *** kinematic and structural parameters of the three-stage auger drill bit were then optimized using the one-factor method,the orthogonal test,and the response surface methodology,*** test method uses a one-way test to determine the central level value of the orthogonal test and a comprehensive balance method to determine the best combination of parameters for the orthogonal test,which is then used as the central value of the response surface test for parameter *** optimal combinations of kinematic and structural parameters of the three-stage auger drill bit are determined and validated using response surface *** optimum combination of parameters was found to be a speed of 129 rpm,a homogenizing mixing time of 24 s,a pitch of 165 mm in the crushing section,and a pitch of 132 mm in the homogenizing *** error between the optimal value of the predicted model using the response surface method and the actual simulated value under the optimal parameters is 4.2%,4.9%,and 5.3%,*** optimized factor parameters provide a refe

关键词： Black soil Mixing homogeneity Orthogonal method Response surface methodology Discrete element method Soil remediation

Self-propelled Leidenfrost droplets on femtosecond-laser-induced surface with periodic hydrophobicity gradient

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International Journal of Extreme Manufacturing 2024年第2期6卷 502-509页

作者： Bohong Li Lan Jiang Xiaowei Li zhipeng wang Peng Yi Laser Micro/Nano Fabrication Laboratory School of Mechanical EngineeringBeijing Institute of TechnologyBeijingPeople’s Republic of China Beijing Institute of Technology Chongqing Innovation Center ChongqingPeople’s Republic of China Yangtze Delta Region Academy of Beijing Institute of Technology JiaxingPeople’s Republic of China

The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so *** Leidenfrost effect can be utilized to significantly reduce motion ***,the use of 3D structures limits the widespread application of self-propulsion based on Leidenfrost droplets in microelectromechanical *** manipulate Leidenfrost droplets,it is necessary to create 2D or quasi-2D *** this study,femtosecond laser is applied to fabricate a surface with periodic hydrophobicity gradient(SPHG),enabling directional self-propulsion of Leidenfrost *** field analysis within the Leidenfrost droplets reveals that the vapor layer between the droplets and the hot surface can be modulated by the SPHG,resulting in directional propulsion of the inner *** viscous force between the gas and liquid then drives the droplet to move.

关键词： self-propelled Leidenfrost droplets periodic hydrophobicity gradient femtosecond laser fabrication