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Chinese Physics Letters 2020年第8期37卷 167-171页

作者： yongyong you Tianran Jiang Tianshu Lai Affiliations State Key Laboratory of Optoelectronic Materials and Technology Department of PhysicsSun Yat-Sen UniversityGuangzhou 510275China

We develop a tightly focused pump-probe absorption technique to study diffusion dynamics of photoexcited *** has many advantages including the simple setup and operations,higher detection sensitivity,an analytic descriptive model and fast data *** dynamics are measured twice,separately using two different-sized probe spots,instead of many time-delayed diffusion profiles of a carrier pocket measured using spatially probe-spot *** analytic model is derived to describe diffusion *** dynamics in GaAs are measured to demonstrate the feasibility of this *** diffusion coefficient is obtained and agrees well with the reported experimental and theoretical results.

关键词： technique. Diffusion excited

Study and application of the influence of inclination angle on the cross-fusion mechanism of high gas thick coal seam

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International Journal of Mining Science and Technology 2025年第1期35卷 69-85页

作者： Pengxiang Zhao Zechen Chang Shugang Li Risheng Zhuo yongyong Jia Qiudong Shao Wen Lei College of Safety Science and Engineering Xi'an University of Science and TechnologyXi’an 710054China Western Mining Gas Intelligent Extraction Engineering Research Centre Xi’an 710054China Xinjiang Coal and Coalbed Methane Engineering Technology Research Centre Urumqi 830091China Xinjiang Key Laboratory of Coal Mine Disaster Intelligent Prevention and Emergency Response Xinjiang Institute of EngineeringUrumqi 830023China Xinjiang Uygur Autonomous Region Coal Science Research Institute Urumqi 830091China Xinjiang Changji Heze Tengda Mining Co. Ltd.Changji 831100China

In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden *** results demonstrated that the boundary of the gas transport zone was located in the region of fracture *** boundary of the gas storage area was located in the abrupt penetration ***,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture *** mathematical representation model of the dip effect in gas transport and storage areas was *** criteria upon which the regional location of the gas transport area and gas storage area can be based were put *** cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as *** research results could provide guidance for realising directional and accurate gas extraction.

关键词： Coal seam dip angle Cross fusion High gas thick coal seam Overburden fracture Gas transport and storage areas

基于改进Unet的地震勘探工区建筑物分割方法研究

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现代电子技术 2025年第3期48卷 135-140页

作者：王雅如王昀江勇勇中石化石油物探技术研究院有限公司江苏南京211103

在地震勘探工区内自动分割建筑物目标对野外物理点布设和避障等工作具有重要意义。针对已有建筑物分割算法存在目标边界分割不完整和小目标分割不准确的问题,提出基于改进Unet的地震勘探工区建筑物分割方法。该方法在原始Unet网络结构... 详细信息

在地震勘探工区内自动分割建筑物目标对野外物理点布设和避障等工作具有重要意义。针对已有建筑物分割算法存在目标边界分割不完整和小目标分割不准确的问题,提出基于改进Unet的地震勘探工区建筑物分割方法。该方法在原始Unet网络结构基础上,首先增加特征批标准化网络层,避免网络训练过程中的梯度消失问题;然后增加多尺度卷积特征融合技术,增强网络特征表达能力;最后使用Diceloss损失函数优化网络参数。实验结果表明,相比于原始Unet,分割IoU提高了约7%,目标边界分割更加完整准确,对小目标也有较好的分割效果,同时对背景环境变化具有更强的适应性。

关键词：地震勘探工区建筑物分割 Unet 多尺度卷积特征融合批标准化 Diceloss

观测不确定性影响下黄河水源涵养区径流情势变化特征

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地理学报 2025年第1期80卷 28-40页

作者：张永勇韩冰曹灿翟晓燕中国科学院地理科学与资源研究所中国科学院陆地水循环及地表过程重点实验室北京100101 中国科学院大学北京100049 中国水利水电科学研究院水利部防洪抗旱减灾工程技术研究中心北京100038

径流观测不确定性是水文学研究领域尚未解决的关键问题之一。当前研究多集中于观测不确定性的来源及其影响解析等,但关于观测不确定性对径流情势特征指标变化趋势的影响研究较少。本文利用1971—2020年黄河水源涵养区5个水文站(黄河源... 详细信息

径流观测不确定性是水文学研究领域尚未解决的关键问题之一。当前研究多集中于观测不确定性的来源及其影响解析等,但关于观测不确定性对径流情势特征指标变化趋势的影响研究较少。本文利用1971—2020年黄河水源涵养区5个水文站(黄河源区黄河沿、唐乃亥和兰州站,渭河咸阳站和伊洛河黑石关站)日径流观测序列,结合正态分布误差模型和趋势检验,检测了观测不确定性影响下五大径流情势特征(量级、事件发生频率、变率、历时和出现时间)16个指标的变化趋势,并采用不确定性宽度、指标斜率显著性变化的个数占比、变异系数和偏离程度量化了观测不确定性的影响。结果表明:①所有站点径流情势呈现低流量显著增加,高流量、平均流量、变率和历时显著减少的特征;黑石关站平均流量和高流量量级、变率和历时显著减少,频率显著增加;咸阳站低流量量级和出现时间显著增加,高流量量级、频率和变率显著减少;黄河源区低流量量级和高流量出现时间显著增加,低流量频率、高流量量级和变率显著减少。②观测不确定性对28.75%的径流情势特征指标的变化趋势影响明显,其中11.25%的指标变化趋势由显著变为不显著和17.5%的指标由不显著变为显著;对其他指标的变化趋势没有影响,其中变化趋势仍保持显著的指标占比为18.75%,变化趋势仍不显著的指标占比为52.50%。③观测不确定性对频率指标的变化趋势影响最大,影响次之为历时指标、变率指标和出现时间指标,而对量级指标的影响最小。

关键词：观测不确定性径流情势正态分布误差模型趋势检测黄河水源涵养区

Zero extension for Poisson's equation

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Science China Mathematics 2020年第4期63卷 721-732页

作者： yongyong Cai Shulin Zhou Beijing Computational Science Research Center Beijing 100193China LMAM and School of Mathematical Sciences Peking UniversityBeijing 100871China

In this paper,we present a necessary and sufficient condition to guarantee that the extended function of the solution for Poisson's equation in a smaller domain by zero extension is still the solution of the corresponding extension problem in a larger *** prove the results under the frameworks of classical solutions,strong solutions and weak ***,we give some observations for the nonlinear pLaplace equation.

关键词： Poisson's equation zero extension a necessary and sufficient condition

Batch process monitoring based on WGNPE–GSVDD related and independent variables

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Chinese Journal of Chemical Engineering 2018年第12期26卷 2549-2561页

作者： yongyong Hui Xiaoqiang Zhao College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou 730050China Key Laboratory of Gansu Advanced Control for Industrial Processes Lanzhou University of TechnologyLanzhou 730050China National Experimental Teaching Center of Electrical and Control Engineering Lanzhou University of TechnologyLanzhou 730050China

In many batch processes, there are related or independence relationships among process variables. The traditional monitoring method usually carries out a single statistical model according to the related or independent method, and in the feature extraction there is not fully taken into account the characterization of fault information, it will make the process monitoring ineffective, so a fault monitoring method based on WGNPE(weighted global neighborhood preserving embedding)–GSVDD(greedy support vector data description) related and independent variables is proposed. First, mutual information method is used to separate the related variables and independent variables. Secondly, WGNPE method is used to extract the local and global structures of the related variables in batch process and highlight the fault information, GSVDD method is used to extract the process information of the independent variables quickly and effectively. Finally, the statistical monitoring model is established to achieve process monitoring based on WGNPE and GSVDD. The effectiveness of the proposed method was verified by the penicillin fermentation process.

关键词： Batch process Monitoring Related and independent variables Global-local Support vector data description

Flash flood type identification and simulation based on flash flood behavior indices in China

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Science China Earth Sciences 2021年第7期64卷 1140-1154页

作者： Xiaoyan ZHAI Liang GUO yongyong ZHANG State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Research Center on Flood and Drought Disaster ReductionChina Institute of Water Resources and Hydropower ResearchBeijing 100038China Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Flash floods present significant heterogeneity over both space and time due to diverse topographic,geomorphologic,and hydro-meteorological conditions of *** identification and simulation of typical flash flood types are of great significance for the mitigation of flash flood disasters at the national *** flood peak indices and dynamic indices were adopted to characterize the behavioral variability of flash *** typical flash flood types and corresponding behavior indices were identified and simulated using statistical analysis(i.e.,principal component analysis,dynamic K-means clustering,and analysis of similarity)and hydrological modelling(i.e.,HEC and XAJ models).There were 177 flash flood events at the hourly scale being selected for case study from eight catchments with various climatic and geographic *** showed that all the flash flood events were clustered into three types(named Types 1,2,and 3).Type 1 was characterized by low peak flow intensity,early flood peak occurrence time,and thin flood process with short *** 2 was characterized by low peak flow intensity,late flood peak occurrence time,and flat flood process with long *** 3 was characterized by high peak flow intensity and late flood peak occurrence *** flood types showed high consistency with their influencing factors(e.g.,catchment forest ratio and drainage area,occurrence time and magnitude of maximum storm intensity,and concentration of a storm event).The simulation performances were basically the same for HEC and XAJ *** for flash flood event simulations,the average relative error varied from 23.25%to 27.98%,from 11.95%to 18.19%,and from 8.30%to18.25%for Types 1,2 and 3,*** average Nash-Sutcliffe efficiency coefficient varied from 0.39 to 0.54,from 0.76 to 0.85,and from 0.86 to 0.91,*** for the six flash flood behavior indices simulations,the average relative rootmean-square error(RMSEr)varie

关键词： Flood similarity Flood behavior Statistical analysis HEC and XAJ models Humid and semi-humid catchments

Marine aquaculture mapping using GF-1 WFV satellite images and full resolution cascade convolutional neural network

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International Journal of Digital Earth 2022年第1期15卷 2047-2060页

作者： yongyong Fu Shucheng you Shujuan Zhang Kun Cao Jianhua Zhang Ping Wang Xu Bi Feng Gao Fangzhou Li College of Resources and Environment Shanxi University of Finance and EconomicsTaiyuanPeople’s Republic of China Land Satellite Remote Sensing Application Center BeijingPeople’s Republic of China Agricultural Ecology and Resource Protection Shandong Agricultural Ecology and Resource Protection StationJinanPeople’s Republic of China Center of Resource and Ecology Environment Research Chinese Academy of Fishery SciencesBeijingPeople’s Republic of China College of Environmental and Resource Sciences Zhejiang UniversityHangzhouPeople’s Republic of China Zhejiang Ecological Civilization Academy AnjiPeople’s Republic of China Development Research Center for Surveying and Mapping Ministry of Natural ResourcesBeijingPeople’s Republic of China

Growing demand for seafood and reduced fishery harvests have raised intensive farming of marine aquaculture in coastal regions,which may cause severe coastal water problems without adequate environmental *** mapping of mariculture areas is essential for the protection of coastal ***,due to the limited spatial coverage and complex structures,it is still challenging for traditional methods to accurately extract mariculture areas from medium spatial resolution(MSR)*** solve this problem,we propose to use the full resolution cascade convolutional neural network(FRCNet),which maintains effective features over the whole training process,to identify mariculture areas from MSR ***,the FRCNet uses a sequential full resolution neural network as the first-level subnetwork,and gradually aggregates higher-level subnetworks in a cascade ***,we perform a repeated fusion strategy so that features can receive information from different subnetworks simultaneously,leading to rich and representative *** a result,FRCNet can effectively recognize different kinds of mariculture areas from MSR *** show that FRCNet obtained better performance than other classical and recently proposed *** developed methods can provide valuable datasets for large-scale and intelligent modeling of the marine aquaculture management and coastal zone planning.

关键词： Mariculture areas GaoFen-1 wide-field-of-view images fully convolutional neural networks deep learning

Thermal-induced snap-through buckling of simply-supported functionally graded beams

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Applied Mathematics and Mechanics(English Edition) 2020年第12期41卷 1821-1832页

作者： yongyong XI QiangLYU Nenghui ZHANG Junzheng WU School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsShanghai UniversityShanghai 200072China

The instability of functionally graded material(FGM)structures is one of the major threats to their service safety in engineering *** paper aims to clarify a long-standing controversy on the thermal instability type of simply-supported FGM ***,based on the Euler-Bernoulli beam theory and von K′arm′an geometric nonlinearity,a nonlinear governing equation of simply-supported FGM beams under uniform thermal loads by Zhang’s two-variable method is ***,an approximate analytic solution to the nonlinear integro-differential boundary value problem under a thermal-induced inhomogeneous force boundary condition is obtained by using a semiinverse method when the coordinate axis is relocated to the bending axis(physical neutral plane),and then the analytical predictions are verified by the differential quadrature method(DQM).Finally,based on the free energy theorem,it is revealed that the symmetry breaking caused by the material inhomogeneity can make the simply-supported FGM beam under uniform thermal loads occur snap-through postbuckling only in odd modes;furthermore,the nonlinear critical load of thermal buckling varies non-monotonically with the functional gradient index due to the stretching-bending coupling *** results are expected to provide new ideas and references for the design and regulation of FGM structures.

关键词： functionally graded beam simply-supported boundary buckling thermal load snap-though free energy theorem

Nanolubricant additives: A review

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Friction 2021年第5期9卷 891-917页

作者： Jun ZHAO Yiyao HUANG yongyong HE Yijun SHI College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Division of Machine Elements LuleåUniversity of TechnologyLuleå97187Sweden

Using nanoadditives in lubricants is one of the most effective ways to control friction and wear,which is of great significance for energy conservation,emission reduction,and environmental *** the scientific and technological development,great advances have been made in nanolubricant additives in the scientific research and industrial *** review summarizes the categories of nanolubricant additives and illustrates the tribological properties of these *** on the component elements of nanomaterials,nanolubricant additives can be divided into three types:nanometal-based,nanocarbon-based,and nanocomposite-based *** dispersion stabilities of additives in lubricants are also discussed in the review *** affecting factors and effective dispersion methods have been investigated in ***,the review summarizes the lubrication mechanisms of nanolubricant additives including tribofilm formation,micro-bearing effect,self-repair performance,and synergistic *** addition,the challenges and prospects of nanolubricant additives are proposed,which guides the design and synthesis of novel additives with significant lubrication and antiwear properties in the future.

关键词： nanolubricant additive dispersion stability tribological properties lubrication mechanism