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Preparation and characterization of a specialized lunar regolith simulant for use in lunar low gravity simulation

International Journal of Mining Science and Technology 2022年第1期32卷 1-15页

作者： Ruilin Li Guoqing Zhou Kang Yan Jun Chen Daqing chen Shangyue Cai Pin-Qiang Mo State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 221116China School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan 430072China

Lunar in-situ resource utilization(ISRU)has been put on the agenda by many countries.Due to the special material nature and low gravity environment,the lunar regolith demonstrates significantly different behavior from terrestrial geomaterials.However,the systematic understanding of its geotechnical behavior is now seriously restricted by the scarcity of lunar regolith and the difficulty in simulating lunar gravity.A new lunar regolith simulant,termed as China University of Mining and Technology Number One(CUMT-1),has been developed to recover properties of the lunar regolith and simulate the lunar gravity by adopting the recently advanced geotechnical magnetic-similitude-gravity model testing(GMMT)method.The CUMT-1 simulant was prepared by reproducing the in-situ formation and fragmentation of the lunar matrix,which plays a key role in the irregular particle morphology.The mineralogical compositions,particle morphology and gradation,specific gravity,bulk density,void ratio,shear strength,and compressibility were determined.After quantifying the magnetization and magnetic-similitude-gravity characteristics,an application of the cone penetration resistance under low gravity was further given.The obtained results are compared to the values known for lunar regolith samples and other simulants,which demonstrates promising characteristics for use in geotechnical engineering-based and scientificbased applications,especially considering the influence of lunar gravity.

关键词： Lunar regolith CUMT-1 simulant Low gravity GMMT method ISRU

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Dynamic Individual Selection and Crossover Boosted Forensic-based Investigation Algorithm for Global Optimization and Feature Selection

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Journal of Bionic Engineering 2023年第5期20卷 2416-2442页

作者： Hanyu Hu Weifeng Shan Jun Chen Lili Xing Ali Asghar Heidari Huiling chen Xinxin He Maofa Wang School of Emergency Management Institute of Disaster PreventionSanhe065201China Earthquake Administration of Anhui Province Hefei230031China Department of Computer Science and Artificial Intelligence Wenzhou UniversityWenzhou325035China Guangxi Key Laboratory of Trusted Software Guilin University of Electronic TechnologyGuilin541004China

The advent of Big Data has rendered Machine Learning tasks more intricate as they frequently involve higher-dimensional data.Feature Selection(FS)methods can abate the complexity of the data and enhance the accuracy,generalizability,and interpretability of models.Meta-heuristic algorithms are often utilized for FS tasks due to their low requirements and efficient performance.This paper introduces an augmented Forensic-Based Investigation algorithm(DCFBI)that incorporates a Dynamic Individual Selection(DIS)and crisscross(CC)mechanism to improve the pursuit phase of the FBI.Moreover,a binary version of DCFBI(BDCFBI)is applied to FS.Experiments conducted on IEEE CEC 2017 with other metaheuristics demonstrate that DCFBI surpasses them in search capability.The influence of different mechanisms on the original FBI is analyzed on benchmark functions,while its scalability is verified by comparing it with the original FBI on benchmarks with varied dimensions.BDCFBI is then applied to 18 real datasets from the UCI machine learning database and the Wieslaw dataset to select near-optimal features,which are then compared with six renowned binary metaheuristics.The results show that BDCFBI can be more competitive than similar methods and acquire a subset of features with superior classification accuracy.

关键词： Feature selection Forensic-based investigation algorithm Crisscross mechanism Global optimization Metaheuristic algorithms Bionic algorithm

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A new era of flood control strategies from the perspective of managing the 2020 Yangtze River flood

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Science China Earth Sciences 2021年第1期64卷 1-9页

作者： jun XIA Jin chen State Key Laboratory of Water Resources and Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China Wuhan University Yangtze River Academy of SciencesChangjiang Water Resources Commission of the Ministry of Water ResourcesWuhan 430015China

Flood control of the Yangtze River is an important part of China’s national water security.In July 2020,due to continuous heavy rainfall,the water levels along the middle-lower reaches of the Yangtze River and major lakes constantly exceeded the warning levels,in which Taihu Lake exceeded its highest safety water level and some stations of Poyang Lake reached their highest water levels in its history.In August 2020,another huge flood occurred in the Minjiang River and the Jialing River in the upper Yangtze River,and some areas of Chongqing Municipality and other cities along the rivers were inundated,resulting in great pressure on flood control and high disaster losses.The 2020 Yangtze River flood has received extensive media coverage and raised concerns on the roles of the Three Gorges Dam and other large reservoirs in flood control.Here we analyze the changes in the pattern of the Yangtze River flood control by comparing the strategies to tackle the three heavy floods occurring in 1954,1998,and 2020.We propose that the overall strategy of the Yangtze River flood control in the new era should adhere to the principle of"Integration of storage and drainage over the entire Yangtze River Basin,with draining floods downstream as the first priority"by using both engineering and non-engineering measures.On the basis of embankments,the engineering measures should use the Three Gorges Dam and other large reservoirs as the major regulatory means,promote the construction of key flood detention areas,keep the floodways clear,and maintain the ecosystem services of wetlands and shoals.In terms of non-engineering measures,we should strengthen adaptive flood risk management under climate change,standardize the use of lands in flood detention areas,give space to floods,and promote the implementation of flood risk maps and flood insurance policies.The ultimate goal of this new flood control system is to enhance the adaptability to frequent floods and increase the resilience to extreme flood disasters.

关键词： The 2020 Yangtze River flood Yangtze River Flood Control System Three Gorges Dam Protection of wetlands and shoals Non-engineering measures

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Superfluid λ transition in charged AdS black holes

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 29-36页

作者： Ning-chen Bai Lei Li jun Tao Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu 610065China School of Physics and Electronic Engineering Sichuan University of Science and EngineeringYibin 643000China

We observe a superfluid λ transition in the P-V criticality of charged Ad S black holes,within a holographic extended thermodynamics that considers the variation of Newton’s constant G.We calculate the critical exponents and find that they coincide with those of a superfluid transition in liquid4He and the Bose-Einstein condensation of hard-sphere Bose gas.Moreover,the independence of entropy and thermodynamic volume in the holographic framework allows us to construct a well-defined Ruppeiner metric.The associated scalar curvature suggests that the black holes show similar microscopic interactions with the hard-sphere Bose gas,where the superfluid(condensed)phase is dominated by repulsive interactions,while the normal(gas)phase is dominated by attractive interactions.These findings might provide us with new insights into the quantum aspect of charged Ad S black holes.

关键词： black hole thermodynamics holography superfluid phase transition Ruppeiner geometry

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Action Recognition with Temporal Scale-Invariant Deep Learning Framework

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China Communications 2017年第2期14卷 163-172页

作者： Huafeng chen Jun Chen Ruimin Hu chen chen Zhongyuan Wang State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 China National Engineering Research Center for Multimedia Software Computer School of Wuhan University Wuhan 430072 China Center for Research in Computer Vision University of Central Florida Orlando FL 32816 USA

Recognizing actions according to video features is an important problem in a wide scope of applications. In this paper, we propose a temporal scale.invariant deep learning framework for action recognition, which is robust to the change of action speed. Specifically, a video is firstly split into several sub.action clips and a keyframe is selected from each sub.action clip. The spatial and motion features of the keyframe are extracted separately by two Convolutional Neural Networks(CNN) and combined in the convolutional fusion layer for learning the relationship between the features. Then, Long Short Term Memory(LSTM) networks are applied to the fused features to formulate long.term temporal clues. Finally, the action prediction scores of the LSTM network are combined by linear weighted summation. Extensive experiments are conducted on two popular and challenging benchmarks, namely, the UCF.101 and the HMDB51 Human Actions. On both benchmarks, our framework achieves superior results over the state.***.the.art methods by 93.7% on UCF.101 and 69.5% on HMDB51, respectively.

关键词： action recognition CNN LSTM

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Anion-derived solid electrolyte interphase realized in usualconcentration electrolyte for Li metal batteries

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Nano Research 2023年第11期16卷 12647-12654页

作者： Zhimeng Hao Geng Li Yong Lu Yichao Cai Gaojing Yang Jun Chen Frontiers Science Center for New Organic Matter Haihe Laboratory of Sustainable Chemical TransformationsKey Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)College of ChemistryNankai UniversityTianjin 300071China National Supercomputer Center in Tianjin Tianjin 300457China

Constructing anion-derived solid electrolyte interphase(SEI)by recruiting anions into the solvation sheath of Li+is extremely conducive to restrain the dendrite growth of Li metal anode.However,the presence of anions in the solvation sheath of Li+is severely hindered by the solvents with strong coordinating ability in conventional electrolyte.Herein,we boost the content of anions in the primary solvation sheath of Li+by employing a solvent with low donor number,2-methyltetrahydrofuran,inducing an anion-derived SEI.As a result,the Li||Cu cells show a high average Coulombic efficiency(>99%)over 500 cycles and the Li||LiFePO4 cells under a low negative/positive capacity ratio of 2:1 exhibit an impressive capacity retention of 90%after 100 cycles.This work provides insights on constructing stable anion-derived SEI and offers guidance in designing electrolytes for stable Li metal batteries.

关键词： anion-derived solid electrolyte interphase donor number solvating power electrolyte lithium metal batteries

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Sparsity-based efficient simulation of cluster targets electromagnetic scattering

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Journal of Systems Engineering and Electronics 2023年第2期34卷 299-306页

作者： TIAN Yuguang LIU Yixin chen Xuan chen Penghui WANG jun chen junwen Communication University of China Beijing 100024China School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Science and Technology on Electromagnetic Scattering Laboratory Beijing 100854China

An efficient and real-time simulation method is proposed for the dynamic electromagnetic characteristics of cluster targets to meet the requirements of engineering practical applications.First,the coordinate transformation method is used to establish a geometric model of the observation scene,which is described by the azimuth angles and elevation angles of the radar in the target reference frame and the attitude angles of the target in the radar reference frame.Then,an approach for dynamic electromagnetic scattering simulation is proposed.Finally,a fast-computing method based on sparsity in the time domain,space domain,and frequency domain is proposed.The method analyzes the sparsity-based dynamic scattering characteristic of the typical cluster targets.The error between the sparsity-based method and the benchmark is small,proving the effectiveness of the proposed method.

关键词： geometric model of the observation scene dynamic electromagnetic scattering simulation sparsity-based method

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A survey of safety separation management and collision avoidance approaches of civil UAS operating in integration national airspace system

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Chinese Journal of Aeronautics 2020年第11期33卷 2851-2863页

作者： Xiangmin GUAN Renli LYU Hongxia SHI Jun Chen Department of General Aviation Civil Aviation Management Institute of ChinaBeijing 100102China General Aviation Institute of Zhejiang JianDe Hangzhou 311600China School of Engineering and Materials Science Queen Mary University of LondonLondon E14NSUnited Kingdom

Recent years have witnessed a booming of the industry of civil Unmanned Aircraft System(UAS).As an emerging industry,the UAS industry has been attracting great attention from governments of all countries and the aviation industry.UAS are highly digitalized,informationized,and intelligent;therefore,their integration into the national airspace system has become an important trend in the development of civil aviation.However,the complexity of UAS operation poses great challenges to the traditional aviation regulatory system and technical means.How to prevent collisions between UASs and between UAS and manned aircraft to achieve safe and efficient operation in the integrated operating airspace has become a common challenge for industry and academia around the world.In recent years,the international community has carried out a great amount of work and experiments in the air traffic management of UAS and some of the key technologies.This paper attempts to make a review of the UAS separation management and key technologies in collision avoidance in the integrated airspace,mainly focusing on the current situation of UAS Traffic Management(UTM),safety separation standards,detection system,collision risk prediction,collision avoidance,safety risk assessment,etc.,as well as an analysis of the bottlenecks that the current researches encountered and their development trends,so as to provide some insights and references for further research in this regard.Finally,this paper makes a further summary of some of the research highlights and challenges.

关键词： Air transportation Collision avoidance Safety Separation control Unmanned aircraft system

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High prevalence of cerebral venous sinus thrombosis in seven Chinese patients with cystathionine β-synthase deficiency

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Chinese Medical Journal 2020年第18期133卷 2247-2249页

作者： Yan-Bin Wen Jun Chen Li-jun Xiao Jie Feng Wen-Ping Gu Department of Neurology Xiangya HospitalCentral South UniversityChangshaHunan 410008China Hunan Clinical Research Center for Cerebrovascular Disease ChangshaHunan 410008China Department of Neurology The First Hospital of ChangshaChangshaHunan 410008China

Homocystinuria due to cystathionin-β-synthase(CBS)deficiency is a rare genetic disease that most often diagnosed in childhood and can cause damage to the multiple systems.[1,2]The inherited mode of CBS gene deficiency is usually autosomal recessive inheritance.More than 160 mutations have been identified in CBS genes so far(http://cbs.***.cuni.cz/index.php),one of the most common mutations is c.833T>C point mutation,and then followed by c.572C>T,c.919G>A,and c.1006C>T point mutations.In 2018,Li et al[2]found eight brand new mutation sites in patients with CBS deficiency in China,pointing out that the CBS mutant site spectrum of Chinese people is significantly different from that of other races.In this paper,we further conducted a retrospective analysis of seven homocystinuric patients of CBS deficiency admitted to our institute.

关键词： patients admitted prevalence

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Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

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Journal of Iron and Steel Research(International) 2024年第4期31卷 828-837页

作者： Gu-Jun Chen Sheng-ping He College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Single argon bubble dynamics in liquid steel under Ruhrstahl-Heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure drop.Additional simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,respectively.The simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be reached.The primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic pressure.When the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,respectively.The bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

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