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Multi-year monitoring of paddy rice planting area in Northeast China using MODIS time series data

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第10期14卷 934-946页

作者： jing-jing SHI jing-feng HUANG feng ZHANG Institute of Agricultural Remote Sensing and Information Application Zhejiang University Key Laboratory of Agricultural Remote Sensing and Information System of Zhejiang Province Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health Zhejiang University

e The objective of this study was to investigate the tempo-spatial distribution of paddy rice in Northeast China using moderate resolution imaging spectroradiometer （MODIS） data. We developed an algorithm for detection and estimation of the transplanting and flooding periods of paddy rice with a combination of enhanced vegetation index （EVI） and land surface water index with a central wavelength at 2130 nm （LSW12130）. In two intensive sites in Northeast China, fine resolution satellite imagery was used to validate the performance of the algorithm at pixel and 3x3 pixel window levels, respectively. The commission and omission errors in both of the intensive sites were approximately less than 20%. Based on the algorithm, annual distribution of paddy rice in Northeast China from 2001 to 2009 was mapped and analyzed. The results demonstrated that the MODIS-derived area was highly correlated with published agricultural statistical data with a coefficient of determination （R^2） value of 0.847. It also revealed a sharp decline in 2003, especially in the Sanjiang Plain located in the northeast of Heilongjiang Province, due to the oversupply and price decline of rice in 2002. These results suggest that the approaches are available for accurate and reliable monitoring of rice cultivated areas and variation on a large scale.

关键词： Paddy rice Moderate resolution imaging spectroradiometer(MODIS) Northeast China Enhanced vegetation index Land surface water index

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煤体注水渗流模型构建及微观主控影响规律

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工程科学学报 2025年第2期47卷 271-281页

作者：王恩茂王刚解树亮魏宏钊冯净梁瀚丹山东科技大学安全与环境工程学院山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地

煤层注水技术是目前矿井除尘的主要技术手段之一，起到润湿煤体、源头减尘的作用.但随着开采深度的增加，煤体孔隙率相对较低，极大影响煤层注水的润湿效果.因此，为了提高煤层注水的效果，结合煤体固有属性、孔隙尺度等影响因素，首先... 详细信息

煤层注水技术是目前矿井除尘的主要技术手段之一，起到润湿煤体、源头减尘的作用.但随着开采深度的增加，煤体孔隙率相对较低，极大影响煤层注水的润湿效果.因此，为了提高煤层注水的效果，结合煤体固有属性、孔隙尺度等影响因素，首先，引入连通孔隙率，建立了包含孔喉、等效孔径、有效孔隙率、毛细管束、迂曲度、流动路径在内的渗流模型；其次，采用高精度射线显微镜（μ-CT）对内蒙古煤矿、同富新煤矿、梅花井煤矿、大黄山煤矿以及磁窖沟煤矿5个煤矿的不同变质程度煤进行扫描，三维重建可视化煤体微观有效孔隙结构，运用分形理论，提取煤体有效连通孔隙结构参数进行计算；再次，通过实验对5个煤矿不同变质程度的煤进行渗透率实测；最后，引入“敏感度”来表征每种影响因素对渗流量的影响程度，运用Morris筛选法，将数值分析法与渗流模型相耦合，定量筛选了煤体坚固性系数、迂曲度分形维数、有效孔隙率、体积分形维数、孔喉半径等主控因素，并分析了各主控因素对注水能力的影响规律.本研究建立了一个综合煤体坚固性系数、迂曲度分形维数、有效孔隙率、体积分形维数和孔喉半径的渗流模型.分析表明，影响注水能力的主控因素依次为煤体坚固性系数、迂曲度分形维数、有效孔隙率、体积分形维数和孔喉半径.注水能力与煤体坚固性系数呈正弦函数关系，随着有效孔隙率的增加，迂曲度分形维数和体积分形维数的减小，注水能力增强.研究结果可为进一步完善煤层注水渗流理论、增强煤层注水润湿效果，防治矿井粉尘灾害提供理论依据.

关键词：煤层注水有效连通孔隙渗流模型主控因素计算机断层扫描

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Influence of HfO2 alloying effect on microstructure and thermal conductivity of HoTaO4 ceramics

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Journal of Advanced Ceramics 2019年第4期8卷 537-544页

作者： Lin CHEN jing feng Faculty of Material Science and Engineering Kunming University of Science and Technology

HfO2 alloying effect has been applied to optimize thermal insulation performance of HoTaO4 ceramics.X-ray diffraction,Raman spectroscopy,and X-ray photoelectron spectroscopy are employed to decide the crystal *** electronic microscopy is utilized to detect the influence of HfO2 alloying effect on *** paper indicates that the same numbers of Ta5+and Ho3+ions of HoTaO4 are substituted by Hf4+cations,and it is defined as alloying *** crystal structural transition is introduced by HfO2 alloying effect,and circular pores are produced in ***2 alloying effect is efficient in decreasing thermal conductivity of HoTaO4 and it is contributed to the differences of ionic radius and atomic weight between Hf4+ions and host cations(Ta5+and Ho3+).The least experimental thermal conductivity is 0.8 W·K–1·m–1 at 900℃,which is detected in 6 and 9 mol%-HfO2 HoTaO4 *** results imply that HfO2–HoTaO4 ceramics are promising thermal barrier coatings(TBCs)due to their extraordinary thermal insulation performance.

关键词： thermal barrier coating(TBC) thermal conductivity rare earth tantalates microstructure alloying effect optical property

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Soil Moisture Monitoring Based on Land Surface Temperature-Vegetation Index Space Derived from MODIS Data

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Pedosphere 2014年第4期24卷 450-460页

作者： ZHANG feng ZHANG Li-Wen SHI jing-jing HUANG jing-feng Institute of Agricultural Remote Sensing and Information Technology Zhejiang University

Soil moisture has been considered as one of the main indicators that are widely used in the fields of hydrology, climate, ecology and others. The land surface temperature-vegetation index （LST-VI） space has comprehensive information of the sensor from the visible to thermal infrared band and can well reflect the regional soil moisture conditions. In this study, 9 pairs of moderate-resolution imaging spectroradiometer （MODIS） products （MOD09A1 and MODllA2）, covering 5 provinces in Southwest China, were chosen to construct the LST-VI space, and then the spatial distribution of soil moisture in 5 provinces of Southwest China was monitored by the temperature vegetation dryness index （TVDI）. Three LST-VI spaces were constructed by normalized difference vegetation index （NDVI）, enhanced vegetation index （EVI）, and modified soil-adjusted vegetation index （MSAVI）, respectively. The correlations between the soil moisture data from 98 sites and the 3 TVDIs calculated by LST-NDVI, LST-EVI and LST-MSAVI, respectively, were analyzed. The results showed that TVDI was a useful parameter for soil surface moisture conditions. The TVDI calculated from the LST-EVI space （TVDIE） revealed a better correlation with soil moisture than those calculated from the LST-NDVI and LST-MSAVI spaces. From the different stages of the TVDIE space, it is concluded that TVDIE can effectively show the temporal and spatial differences of soil moisture, and is an effective approach to monitor soil moisture condition.

关键词： enhanced vegetation index modified soil-adjusted vegetation index normalized difference vegetation index temperature vegetation dryness indices

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COMPREHENSIVE EVALUATION OF FAULT-TOLERANT PROPERTIES OF REDUNDANT ROBOTS

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Chinese Journal of Mechanical Engineering 2008年第4期21卷 22-26页

作者： ZHAO jing feng Dengdian College of Mechanical Engineening and Applied Electronics Technology Beijing University of Technology Beijing 100124 China

When a redundant robot performs a fault-tolerant operation for locked joint failures, its fault tolerant properties should include dexterity and sudden change of joint velocity at the moment of locking failed joints and the dexterity during the post-failure. Firstly three fault-tolerant indexes, reduced condition number, sudden change of relative joint velocity and centrality are proposed, which can comprehensively evaluate the kinematical performance of a redundant robot during its entire fault-tolerant operations. Then, the influence of the initial postures of robot＇s end-effector on these fault-tolerant indexes is analyzed with a planar robot and a spatial robot. Simulation results show that for a given task the joint trajectory with the best comprehensive effect of fault tolerance can be determined by optimizing the initial posture of a robot.

关键词： Redundant robot Fault-tolerant properties Comprehensive evaluation

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Refined empirical line method to calibrate IKONOS imagery

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第4期7卷 641-646页

作者： XU Jun-feng HUANG jing-feng Institute of Agricultural Remote Sensing and lnformation Technology Zhejiang University Hangzhou 310029. China

To extract quantitative biophysical parameters such as leaf biomass and leaf chlorophyll concentration from the remotely sensed imagery, the effect of atmospheric attenuation must be removed. The refined empirical line （REL） method was used to calibrate the IKONOS multispectral imagery. The IKONOS digital numbers （DN） were converted to the at-satellite reflectance, then the linear relation between at-satellite reflectance and surface spectral reflectance （ρA） was derived from six bright targets of known reflectance in the image, and modelled estimates of the image reflectance at ρA=0. Validation targets were used to test the feasibility of REL method. The mean relative errors between ρA retrieved from IKONOS image using REL method and ground-measured ρA were 11%, 13%, 3% and 5% in the IKONOS blue, green, red and near-infrared （NIR） respectively. When dark targets are unavailable or measurement of dark target is inconvenient, the REL method was most crucial for retrieving surface spectral reflectance. The REL offers a simple approach for quantitative retrieval of biophysical parameters from IKONOS imagery.

关键词： Calibration Refined empirical line (REL) method IKONOS

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Tribological properties of cobalt-based alloy coating with different cobalt contents by electro-spark deposition

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Rare Metals 2013年第1期32卷 40-46页

作者： Qi-feng jing Ye-Fa Tan Engineering Institute of Engineering Corps PLA University of Science & Technology Unit 78649 of PLA

The cobalt-based alloy coating with different Co contents was deposited on 45 steel by electro-spark deposition with the self-made electrode. The coating has a compact and uniform microstructure with low porosity and no visible microcracks. When Co content increases grad- ually, oxygen content of coating samples 1-5 decreases first and then increases in the range of 2.52 wt%-3.05 wt%; sample 3 has the lowest oxygen content of 2.52 %. Mi- crohardness of the coating is improved remarkably com- pared with the substrate （HV 230.18）. With Co content increasing, microhardness of the coating samples 1-5 first rises slightly and then declines rapidly in the range of HV 580.61-1052.33. Sample 3 gets the maximum of HV 1052.33, which is about 4.6 times that of the substrate. The coating presents excellent wear resistance, which first increases and then decreases when Co content increases. Sample 3 shows the best wear resistance of about 6.4 times that of the substrate. Main wear mechanism of the coating is abrasive wear and fatigue wear, along with oxidation wear under high speed or heavy load conditions.

关键词： Electro-spark deposition Cobalt Content Microstructure Wear resistance Wear mechanism

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Estimation in Linear Regression with Laplace Measurement Error Using Tweedie-Type Formula

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Journal of Systems Science & Complexity 2019年第4期32卷 1211-1230页

作者： SHI Jianhong feng jing SONG Weixing School of Mathematics and Computer Science Shanxi Normal UniversityLinfen 041000China Department of Statistics Kansas State UniversityManhattan 66503KS

Based on a Tweedie-type formula developed under the Laplace distribution,this paper proposes a new bias-corrected estimator of the regression parameters in a simple linear model when the measurement error follows a Laplace *** sample properties,including the consistency and the asymptotic normality,are *** finite sample performance of the proposed estimators are evaluated via simulation studies,as well as comparison studies with some existing estimation procedures.

关键词： Asymptotic normality consistency kernel estimator Laplace measurement error simple linear ME model

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An overview of thermoelectric films:Fabrication techniques,classification,and regulation methods

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Chinese Physics B 2018年第4期27卷 12-26页

作者： jing-jing feng Wei Zhu Yuan Deng School of Materials Science and Engineering Beihang University Beijing 100191 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100083 China

Thermoelectric materials have aroused widespread concern due to their unique ability to directly convert heat to electricity without any moving parts or noxious *** advantages of two-dimensional structures of thermoelectric films,the potential applications of thermoelectric materials are diversified,particularly in ***-controlled nanostructures in thermoelectric films are effective to optimize the electrical and thermal transport,which can significantly improve the performance of thermoelectric *** this paper,various physical and chemical approaches to fabricate thermoelectric films,including inorganic,organic,and inorganic–organic composites,are summarized,where more attentions are paid on the inorganic thermoelectric films for their excellent thermoelectric ***,strategies for enhancing the performance of thermoelectric films are also discussed.

关键词： thermoelectric films fabrication techniques classification regulation methods

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Comparative Studies of Two Major Sets of Tibetan Medical Paintings: A Historical Perspective

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Chinese Journal of Integrative Medicine 2019年第11期25卷 803-811页

作者： ZHEN Yan CAI jing-feng China Institute for History of Medicine and Medical Literature China Academy of Chinese Medical Sciences

Tibetan medicine, one of the time-honored medical systems in the world, has increasingly been receiving attention the world over. Tibetan medical paintings (TMP, tib. Smart thang) has become one of the focal points in the studies of this medical system. To date, there are many atlases and publications on TMP, which are principally based on the two major sets of TMP series existing today in the world, the Lhasa set and the Buryat set. It has been found that the Buryat set is based on the Lhasa set, which was brought in late 19th to the first half of the 20th century from Tibet to Buryatia, Russia. A careful investigation on the basic structure of the two sets reveals that there are many differences between the two sets of paintings, including the total number of the paintings invoIved, of which some are missing in one set, the details of the captions of some of the paintings, the existenee of the 80th painting and its supervisor, and the overall order of the entire set, etc. The details of the differences are elaborated and discussed, and the prospective of developing the research to arrive at a standard and perfect TMP set in the future is also analyzed and anticipated.

关键词： Tibetan medical painting Sman thang Lhasa set Buryat set Tibetan painting art Sde srid Sangs rgyas rgya mtsho

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