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Three-dimensional(3D)parametric measurements of individual gravels in the Gobi region using point cloud technique

Journal of Arid Land 2024年第4期16卷 500-517页

作者： JING xiangyu huang Weiyi KAN Jiangming College of Engineering Beijing Forestry UniversityBeijing 100083China Key Laboratory of State Forestry Administration on Forestry Equipment and Automation Beijing 100083China

Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed dunes.Its presence significantly influences the movement of sand and dust.However,the complex origins and diverse materials constituting the Gobi result in notable differences in saltation processes across various Gobi surfaces.It is challenging to describe these processes according to a uniform morphology.Therefore,it becomes imperative to articulate surface characteristics through parameters such as the three-dimensional(3D)size and shape of gravel.Collecting morphology information for Gobi gravels is essential for studying its genesis and sand saltation.To enhance the efficiency and information yield of gravel parameter measurements,this study conducted field experiments in the Gobi region across Dunhuang City,Guazhou County,and Yumen City(administrated by Jiuquan City),Gansu Province,China in March 2023.A research framework and methodology for measuring 3D parameters of gravel using point cloud were developed,alongside improved calculation formulas for 3D parameters including gravel grain size,volume,flatness,roundness,sphericity,and equivalent grain size.Leveraging multi-view geometry technology for 3D reconstruction allowed for establishing an optimal data acquisition scheme characterized by high point cloud reconstruction efficiency and clear quality.Additionally,the proposed methodology incorporated point cloud clustering,segmentation,and filtering techniques to isolate individual gravel point clouds.Advanced point cloud algorithms,including the Oriented Bounding Box(OBB),point cloud slicing method,and point cloud triangulation,were then deployed to calculate the 3D parameters of individual gravels.These systematic processes allow precise and detailed characterization of individual gravels.For gravel grain size and volume,the correlation coefficients between point cloud and manual measurements all exceeded 0.9000,confirming the feasibility of the proposed methodology for measuring 3D parameters of individual gr

关键词： Gobi gravels three-dimensional(3D)parameters point cloud 3D reconstruction Random Sample Consensus(RANSAC)algorithm Density-Based Spatial Clustering of Applications with Noise(DBSCAN)

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Porous nanofibrous dressing enables mesenchymal stem cell spheroid formation and delivery to promote diabetic wound healing

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Chinese Journal of Chemical Engineering 2024年第4期68卷 156-164页

作者： Kexin Zhang Wenmin Zhang Heng An Zhe huang Yanzhen Wen xiangyu Jiao Yongqiang Wen College of Chemical Engineering and Technology Taiyuan University of Science and TechnologyTaiyuan 030024China Beijing Key Laboratory for Bioengineering and Sensing Technology Daxing Research InstituteSchool of Chemistry&Biological EngineeringUniversity of Science&Technology BeijingBeijing 100083China

Delayed and nonhealing of diabetic wounds imposes substantial economic burdens and physical pain on patients.Mesenchymal stem cells(MSCs)promote diabetic wound healing.Particularly when MSCs aggregate into multicellular spheroids,their therapeutic effect is enhanced.However,traditional culture platforms are inadequate for the efficient preparation and delivery of MSC spheroids,resulting in inefficiencies and inconveniences in MSC spheroid therapy.In this study,a three-dimensional porous nanofibrous dressing(NFD)is prepared using a combination of electrospinning and homogeneous freeze-drying.Using thermal crosslinking,the NFD not only achieves satisfactory elasticity but also maintains notable cytocompatibility.Through the design of its structure and chemical composition,the NFD allows MSCs to spontaneously form MSC spheroids with controllable sizes,serving as MSC spheroid delivery systems for diabetic wound sites.Most importantly,MSC spheroids cultured on the NFD exhibit improved secretion of vascular endothelial growth factor,basic fibroblast growth factor,and hepatocyte growth factor,thereby accelerating diabetic wound healing.The NFD provides a competitive strategy for MSC spheroid formation and delivery to promote diabetic wound healing.

关键词： Electrospinning Homogenization Biomedical engineering Nanomaterials Stem cell spheroids Diabetic wound healing

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Integrated visual navigation based on angles-onlymeasurements for asteroid final landing phase

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Astrodynamics 2023年第1期7卷 69-82页

作者： Ronghai Hu xiangyu huang Chao Xu Beijing Institute of Control Engineering Beijing 100190China National Laboratory of Space Intelligent Control Beijing 100190China

Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the pose of the lander during the final landing phase.The system used the lander's global pose information provided by an orbiter,which was deployed in space in advance,and its relative motion information in adjacent images to jointly estimate its optimal state.First,the landmarks on the asteroid surface and markers on the lander were identified from the images acquired by the orbiter.Subsequently,an angles-only measurement model concerning the landmarks and markers was constructed to estimate the orbiter's position and lander's pose.Subsequently,a method based on the epipolar constraint was proposed to estimate the lander's inter-frame motion.Then,the absolute pose and relative motion of the lander were fused using an extended Kalman filter.Additionally,the observability criterion and covariance of the state error were provided.Finally,synthetic image sequences were generated to validate the proposed navigation system,and numerical results demonstrated its advance in terms of robustness and accuracy.

关键词： asteroid final landing phase visual navigation angles-only measurements inter-frame motion estimation state fusion

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Utilization of 3D printing technology in hepatopancreatobiliary surgery

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第2期25卷 123-134页

作者： Wujiang SHI Jiangang WANG Jianjun GAO Xinlei ZOU Qingfu DONG Ziyue huang Jialin SHENG Canghai GUAN Yi XU Yunfu CUI xiangyu ZHONG Department of Hepatopancreatobiliary Surgery the Second Affiliated Hospital of Harbin Medical UniversityHarbin150086China Department of General Surgery Tangdu HospitalAir Force Medical UniversityXi’an710032China Key Laboratory of Basic Pharmacology of Ministry of Education Zunyi Medical UniversityZunyi563006China Key Laboratory of Functional and Clinical Translational Medicine Fujian Province UniversityXiamen Medical CollegeXiamen361000China Department of Pathology Li Ka Shing Faculty of MedicineThe University of Hong KongHong KongChina Jiangsu Province Engineering Research Center of Tumor Targeted Nano Diagnostic and Therapeutic Materials Yancheng Teachers UniversityYancheng224007China Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province Hangzhou310053China Key Laboratory of Gastrointestinal Cancer(Fujian Medical University) Ministry of EducationSchool of Basic Medical SciencesFujian Medical UniversityFuzhou350122China Key Laboratory of Myocardial Ischemia Harbin Medical UniversityMinistry of EducationHarbin150086China

The technology of three-dimensional(3D)printing emerged in the late 1970s and has since undergone considerable development to find numerous applications in mechanical engineering,industrial design,and biomedicine.In biomedical science,several studies have initially found that 3D printing technology can play an important role in the treatment of diseases in hepatopancreatobiliary surgery.For example,3D printing technology has been applied to create detailed anatomical models of disease organs for preoperative personalized surgical strategies,surgical simulation,intraoperative navigation,medical training,and patient education.Moreover,cancer models have been created using 3D printing technology for the research and selection of chemotherapy drugs.With the aim to clarify the development and application of 3D printing technology in hepatopancreatobiliary surgery,we introduce seven common types of 3D printing technology and review the status of research and application of 3D printing technology in the field of hepatopancreatobiliary surgery.

关键词： 3D printing Hepatopancreatobiliary surgery Organ model Cancer model

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Deep electrical structures of Qinzhou-Fangcheng Junction Zone in Guangxi and seismogenic environment of the 1936 Lingshan M6^(3/4)earthquake

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Science China Earth Sciences 2024年第2期67卷 584-603页

作者： Bin ZHOU Chunheng YAN Yan ZHAN xiangyu SUN Sha LI Xiang WEN Yajun MO Yongdong YUAN Yuan YUAN Meili huang Earthquake Agency of Guangxi Zhuang Autonomous Region Nanning530022China State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing100029China Guangxi Geophysical Survey Institute Liuzhou545005China

The tectonic position of the southwest section of the Qinzhou Bay-Hangzhou Bay Tectonic Junction Zone(QHTJZ)can be determined by examining the Qinzhou-Fangcheng Junction Zone(QFJZ)in Guangxi.This zone is significant because it was the location of the largest earthquake ever recorded in the inland region of South China,specifically the 1936 Lingshan M6^(3/4)earthquake in Guangxi.Therefore,this region serves as an optimal location for researching the origins of intraplate earthquakes in South China.This study presents a display of a broadband magnetotelluric(MT)prospecting profile that traverses the Guangxi QFJZ and the Lingshan earthquake zone,extending from the northwest(NW)to the southeast(SE).A resistivity structure model was generated using three-dimensional(3D)inversion technology along the profile.The main faults in QFJZ were analyzed in terms of their deep extension forms and tectonic attributes.This analysis was performed by integrating the results obtained from geology,gravity,wave velocity ratio,Global Position System(GPS),and geothermal flow.The results showed that(1)the Dongzhong-Xiaodong fault(DXf),the eastern Fangcheng-Lingshan fault(FLf2),and the eastern Hepu-Beiliu fault(HBf2)were all trans-crustal deep faults,and crust-mantle ductile shear zones developed in the deep part.Two electrical boundary zones,DXf and HBf2,were identified.DXf inclined towards the northwest,while HBf2 inclined towards the southeast.The FangchengLingshan fault(FLf)exhibits a tectonic style resembling a“flower”shape in the upper crust.In the deeper section,it is characterized by an electrical boundary zone that gradually slopes towards the southeast direction.(2)The Hunan-Guangxi Passive Continental Margin(HGPCM)on the NW side of DXf had a stratified resistivity structure and relatively stable Bouguer gravity anomalies,which conformed to the quasi-craton tectonic attribute of the local failure at the southeastern margin of the Yangtze Block(YB).The southeastern side of this block is marked by the presence of the QFJZ and Yunk

关键词： South China Block Qinzhou-Fangcheng Junction Zone Magnetotelluric 1936 Lingshan M6^(3/4)earthquake Deep seismogenic environment

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Thermal and mechanical characterization of under-2-μm-thick AlCrNbSiTi high-entropy thin film

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Energy Storage and Saving 2024年第1期3卷 52-59页

作者： Yibo Wang Xiaona huang Yan Liu xiangyu Zhang Bing Yang Yanan Yue School of Power and Mechanical Engineering Wuhan UniversityWuhan430072China

High-entropy alloys(HEAs)exhibit extraordinary physical properties such as superior strength-to-weight ratios and enhanced corrosion and oxidation resistance,making them potentially useful in energy storage and gener-ation industries.However,thermal and mechanical properties of HEAs with various compositions vary signifi-cantly.Furthermore,these properties have rarely been investigated simultaneously owing to material or instru-mentation limitations.Herein,we synthesize an HEA(AlCrNbSiTi)coating with a thickness of less than 2μm.We customize a frequency-domain photothermal testing system to characterize the thermal and mechanical proper-ties of the proposed coating with high accuracy.Owing to the large mixing enthalpy of the Al-Ti,Nb-Si,and Ti-Si pairs in the coating,its hardness and elastic modulus are 15.2 and 254.7 GPa,respectively,which are higher than those of previously reported HEAs.The thermal conductivity of the AlCrNbSiTi coating is characterized to be 2.90 W·m^(−1)·K^(−1),within the expected range and well explained by the free-electron consistency diversity and phonon scattering from the amorphous structure.Additionally,the coating exhibits adequate wear performance,with a wear rate of 5.4×10^(−8) mm^(3)·N^(−1)·m^(−1).This relatively low thermal conductivity,combined with extraordi-nary mechanical properties,makes the proposed material an excellent candidate as a protective coating material for nuclear reactor components which require high strength,irradiation resistance,and thermal protection.

关键词： High-entropy alloys Thin coating Thermal conductivity Mechanical properties Noncontact photothermal technique

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Adaptive entry guidance for the Tianwen-1 mission

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Astrodynamics 2022年第1期6卷 17-26页

作者： Minwen Guo xiangyu huang Maodeng Li Jinchang Hu Chao Xu Beijing Institute of Control Engineering Beijing 100094China National Key Laboratory of Science and Technology on Space Intelligent Control Beijing 100094China

To meet the requirements of the Tianwen-1 mission,adaptive entry guidance for entry vehicles,with low lift-to-drag ratios,limited control authority,and large initial state bias,was presented.Typically,the entry guidance law is divided into four distinct phases:trim angle-of-attack phase,range control phase,heading alignment phase,and trim-wing deployment phase.In the range control phase,the predictor–corrector guidance algorithm is improved by planning an on-board trajectory based on the Mars Science Laboratory(MSL)entry guidance algorithm.The nominal trajectory was designed and described using a combination of the downrange value and other states,such as drag acceleration and altitude rate.For a large initial state bias,the nominal downrange value was modified onboard by weighing the landing accuracy,control authority,and parachute deployment altitude.The biggest advantage of this approach is that it allows the successful correction of altitude errors and the avoidance of control saturation.An overview of the optimal trajectory design process,including a discussion of the design of the initial flight path angle,relevant event trigger,and transition conditions between the four phases,was also presented.Finally,telemetry data analysis and post-flight assessment results were used to illustrate the adaptive guidance law,create good conditions for subsequent parachute reduction and power reduction processes,and gauge the success of the mission.

关键词： Tianwen-1 mission adaptive entry guidance on-board trajectory planning telemetry data analysis post-flight assessment

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End-to-end Mars entry,descent,and landing modeling and simulations for Tianwen-1 guidance,navigation,and control system

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Astrodynamics 2022年第1期6卷 53-67页

作者： Chao Xu xiangyu huang Minwen Guo Maodeng Li Jinchang Hu Xiaolei Wang Beijing Institute of Control Engineering Beijing 100094China National Key Laboratory of Science and Technology on Space Intelligent Control Beijing 100094China

On May 15,2021,the Tianwen-1 lander successfully touched down on the surface of Mars.To ensure the success of the landing mission,an end-to-end Mars entry,descent,and landing(EDL)simulator is developed to assess the guidance,navigation,and control(GNC)system performance,and determine the critical operation and lander parameters.The high-fidelity models of the Mars atmosphere,parachute,and lander system that are incorporated into the simulator are described.Using the developed simulator,simulations of the Tianwen-1 lander EDL are performed.The results indicate that the simulator is valid,and the GNC system of the Tianwen-1 lander exhibits excellent performance.

关键词： Mars entry,descent,and landing(EDL) modeling and simulation Tianwen-1 lander guidance,navigation,and control(GNC)

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Time domain characteristic analysis of non-coupled PCNN

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Optoelectronics Letters 2024年

作者： DENG xiangyu YU Haiyue huang Xikai College of Physics and Electronic Engineering Northwest Normal University

Pulse-coupled neural network (PCNN) is a multi-parameter artificial neural network， and the characteristics of PCNN can be fully explored by analyzing different simplified networks. In this paper， the firing characteristics of non-coupled PCNN with coupled linking term are studied， the mathematical expressions of firing time and interval are summarized， and further analyze the influence of linking weight matrix and linking weight coefficient on network characteristics， and give the constraints of parameters. Finally， extensive verification experiments were carried out for the phenomenon of image edge detection that occurs in the experiments， which provides theoretical support for further research and application of PCNN model.

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GeoChip-based microbial functions in biogeochemical cycles and their responses to environmental factors in Tengchong hot springs

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Journal of Earth Science 2024年

作者： Muhammad Inayat Ullah Khan Liuqin huang Geng Wu Jian Yang xiangyu Guan Hongchen Jiang School of Environmental Studies China University of Geosciences School of Ocean Sciences China University of Geosciences Beijing State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Microorganisms actively participate in biogeochemical cycling processes and play a crucial role in maintaining the dynamic balance of hot spring ecosystems. However， the distribution of microbial functional genes and their influencing factors in hot springs remain largely unclear. Therefore， this study investigated the microbial functional genes and their potential for controlling biogeochemical cycles (C， N， S， and P) in the hot Springs of Tengchong， China， using the Geochip method， a functional gene microarray technology. The examined hot springs have very different microbial functional genes. A total of 22736 gene probe signals were identified， belonging to 567 functional genes and associated with 15 ecological functions， mainly involving stress response， carbon cycle， nitrogen cycle， sulfur cycle， phosphorus cycle and energy processes. The amyA， narG， dsrA and ppx genes were most abundant in carbon， nitrogen， sulfur and phosphorus cycles， respectively， and were significantly correlated with pH， temperature and SO42-. The diversity and abundance of detected gene probes were negatively correlated with temperature. The α-diversity (i.e.， Shannon index) was high at low temperature and low pH. Molecular functional interactions revealed by the gene connectivity levels were negatively correlated with temperature， pH and SO42-. These results suggested that the abundance， diversity and interactions of microbial functional genes were significantly influenced by geochemical parameters?. In addition， some genera possessed functional genes related to carbon， nitrogen， sulfur， and phosphorus cycles and can synergistically control the biogeochemical cycles of carbon， nitrogen， sulfur and phosphorus. These findings provide new insights into the functional potentials of microorganisms to participate in biogeochemical cycles and their responses to environmental factors in hot springs.

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