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Spatial-temporal population dynamics of the critically endangered Blue-crowned Laughingthrush Pterorhinus courtoisi:a 22-year longitudinal study

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Science China(Life Sciences) 2024年第8期67卷 1769-1771页

作者： Tao Liu Jutao He Chang Xiao Jie Liu Jie Sun Minling Li Yuanhua Hong Weiwei Zhang Fuwen Wei Jiangxi Provincial Key Laboratory of Conservation Biology Jiangxi Agricultural UniversityNanchang 330045China Forestry Bureau of Wuyuan Shangrao 333299China

Dear Editor,Population size is a crucial indicator in evaluating the conservation status of a *** the patterns of population fluctuation and the distribution range of endangered species is important for biodiversity c... 详细信息

关键词： Population crown dynamics

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Design of crown pillar thickness using finite element method and multivariate regression analysis

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International Journal of Mining Science and Technology 2017年第6期27卷 955-964页

作者： Kumar Hemant Deb Debasis Chakravarty D. Department of Mining Engineering Indian Institute of Technology (Indian School of Mines) Dhanbad 826004 India Department of Mining Engineering Indian Institute of Technology Kharagpur 721302 India

Minerals are now being extracted from deep mines due to drying up of resource in shallow ground. The need for suitable supports and ground control mechanisms for safe mining necessitates proper pillar design with filling technology. In addition, high horizontal stress may cause collapse of hanging wall and footwall rocks, hence designing of suitable crown pillars is absolutely necessary for imposing overall safety of the stopes. This paper provides a methodology for the evaluation of the required thickness of crown pillars for safe operation at depth ranging from 600 m to 1000 m. Analyses are conducted with the results of 108 non-linear numerical models considering Drucker-Prager material model in plane strain condition. Material properties of ore body rock and thickness of crown pillars are varied and safety factors of pillars estimated. Then, a generalized statistical relationship between the safety factors of crown pillars with the various input parameters is developed. The developed multivariate regression model is utilized for generating design/stability charts of pillars for different geo-mining *** design charts can be used for the design of crown pillar thickness with the depth of the working,taking into account the changes of the rock mass conditions in underground metal mine.

关键词： Cut and fill mining crown pillar FEM Regression model Design chart

Nonlinear mixed-effects height to crown base and crown length dynamic models using the branch mortality technique for a Korean larch( Larix olgensis ) plantations in northeast China

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Journal of Forestry Research 2019年第6期30卷 2095-2109页

作者： Weiwei Jia Dongsheng Chen Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education School of ForestryNortheast Forestry UniversityHarbin 150040HeilongjiangPeople’s Republic of China Research Institute of Forestry Chinese Academy of ForestryKey Laboratory of Tree Breeding and CultivationState Forestry AdministrationBeijing 100091People’s Republic of China

Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast ***,its timber quality and growth ability are largely infl uenced by crown size,structure and *** majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been ***,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch *** nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic *** data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast *** results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently *** growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and *** HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with *** CL was positively correlated with BAS and CCF,but negatively correlated with DBH *** fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL ***,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was ***,from the point of view of application,we should take care to avoid setting up over-complex *** HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.

关键词： Larix olgensis plantation Height to crown base crown length Branch mortality technique Nonlinear mixed-eff ects models

Effect of viscosity on motion of splashing crown in high speed drop impact

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Applied Mathematics and Mechanics(English Edition) 2017年第12期38卷 1709-1720页

作者： Shihao YANG Yi AN Qingquan LIU Institute of Mechanics Chinese Academy of Sciences School of Aerospace Engineering Beijing Institute of Technology

A splashing crown is commonly observed when a high-speed drop impacts a liquid film. The influence of the liquid viscosity on the crown＇s evolution is not yet clear. We review several existing theories of this problem, and carry out a series of numerical simulations. We find that a three-segment model can describe the crown＇s motion. In the very early stage when the crown is barely visible, the influence of viscosity is small. Later, a shallow water approach used in most existing models is applicable as long as the initial conditions are formulated properly. They depend on viscous dissipation in the intermediate period. Preliminary estimation based on a dissipation function is proposed to characterize the influence of viscosity in this problem.

关键词： drop impact crown viscosity coupled level-set volume of fluid (CLSVOF) method

Study and application of crown feedback control in hot strip rolling

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Journal of University of Science and Technology Beijing 2007年第2期14卷 190-194页

作者： Xiaodong Wang Anrui He Quan Yang Zhi Xie Hongtao Yang National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China Anshan Iron and Steel Corporation Anshan 114002 China

crown feedback control is one part of the automatic shape control （ASC） system. On the basis of large simulation researches conducted, a linear crown feedback control model was put forward and applied in actual strip rolling. According to its successful op- eration in the ASP 1700 hot strip mill of Angang Group for one year and also from the statistical results of several crown measurements, it can be definitely said that this control model is highly effective and shows stable performance. The control effectiveness of different gauges of strips with the feedback control is found to increase by 10%-30% compared with that without feedback control.

关键词： hot rolled strip crown feedback control automatic shape control profiler

RhizoVision crown:An Integrated Hardware and Software Platform for Root crown Phenotyping

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Plant Phenomics 2020年第1期2卷 25-39页

作者： Anand Seethepalli Haichao Guo Xiuwei Liu Marcus Griffiths Hussien Almtarfi Zenglu Li Shuyu Liu Alina Zare Felix B.Fritschi Elison B.Blancaflor Xue-Feng Ma Larry M.York Noble Research Institute LLC2510 Sam Noble ParkwayArdmoreOK 73401USA Division of Plant Sciences University of MissouriColumbiaMO 65201USA Crop and Soil Sciences University of GeorgiaAthensGA 30602USA Texas A&M AgriLife Research Texas A&M University SystemAmarilloTX 79106USA Department of Electrical and Computer Engineering University of FloridaGainesvilleFL 32601USA

Root crown phenotyping measures the top portion of crop root systems and can be used for marker-assisted breeding,genetic mapping,and understanding how roots influence soil resource *** imaging protocols and image analysis programs exist,but they are not optimized for high-throughput,repeatable,and robust root crown *** RhizoVision crown platform integrates an imaging unit,image capture software,and image analysis software that are optimized for reliable extraction of measurements from large numbers of root *** hardware platform utilizes a backlight and a monochrome machine vision camera to capture root crown *** RhizoVision Imager and RhizoVision Analyzer are free,open-source software that streamline image capture and image analysis with intuitive graphical user *** RhizoVision Analyzer was physically validated using copper wire,and features were extensively validated using 10,464 groundtruth simulated images of dicot and monocot root *** platform was then used to phenotype soybean and wheat root crowns.A total of 2,799 soybean(Glycine max)root crowns of 187 lines and 1,753 wheat(Triticum aestivum)root crowns of 186 lines were *** component analysis indicated similar correlations among features in both *** maximum heritability was 0.74 in soybean and 0.22 in wheat,indicating that differences in species and populations need to be *** integrated RhizoVision crown platform facilitates high-throughput phenotyping of crop root crowns and sets a standard by which open plant phenotyping platforms can be benchmarked.

关键词： crown utilize intuitive

Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

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Science China Chemistry 2009年第11期52卷 1858-1864页

作者： XU Chao SHEN XingHai CHEN QingDe GAO HongCheng Department of Applied Chemistry College of Chemistry and Molecular EngineeringBeijing National Laboratory for Molecular Sciences(BNLMS)Peking UniversityBeijing 100871China

The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids(ILs) as solvents has been *** distribution ratio of Sr2+ can reach as high as 103 under certain conditions,much larger than that in DCH18C6/n-octanol *** extraction capacity depends greatly on the structure of ionic *** Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na+ and K+ in the aqueous *** is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

关键词： strontium ions ionic liquid extraction crown ether

Multi-environment QTL mapping of crown root traits in a maize RIL population

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The Crop Journal 2020年第4期8卷 645-654页

作者： Pengcheng Li Yingying Fana Shuangyi Yina Yunyun Wanga Houmiao Wang Yang Xu Zefeng Yang Chenwu Xu Jiangsu Key Laboratory of Crop Genetics and Physiology/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding Agricultural College of Yangzhou UniversityYangzhou 225009JiangsuChina Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhou 225009JiangsuChina Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China Yangzhou UniversityYangzhou 225009JiangsuChina

crown root traits,including crown root angle(CRA),diameter(CRD),and number(CRN),are major determining factors of root system architecture,which influences crop *** maize,the genetic mechanisms determining crown root traits in the field are largely ***,CRD,and CRN were evaluated in a recombinant inbred line population in three field *** phenotypic variation was observed for crown root traits,and all measured traits showed significant genotype–environment ***(SEA)and multi-environment(MEA)quantitative trait locus(QTL)analyses were conducted for CRA,CRD,and *** 46 QTL detected by SEA,most explained less than 10%of the phenotypic variation,indicating that a large number of minor-effect QTL contributed to the genetic component of these *** detected 25 QTL associated with CRA,CRD,and CRN,and 2 and 1 QTL were identified with significant QTL-by-environment interaction effects for CRA and CRD,respectively.A total of 26.1%(12/46)of the QTL identified by SEA were also detected by MEA,with many being detected in more than one *** findings contribute to our understanding of the phenotypic and genotypic patterns of crown root traits in different *** identified environment-specific QTL and stable QTL may be used to improve root traits in maize breeding.

关键词： crown traits maize

Simulation Analysis on Quasistatic Characteristics of Multistage Face Gears with Double crown Surfac

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Computer Modeling in Engineering & Sciences 2019年第2期118卷 447-470页

作者： Xingbin Chen Qingchun Hu Zhongyang Xu Yao Ding Qianli Mai Chune Zhu School of Mechanical and Automotive engineering South China University of TechnologyGuangzhou510641China eBizprise Technology(TJ)Limited Tianjin300040China Institute for Biomedical and Pharmaceutical Sciences Guangdong University of TechnologyGuangzhou510006China.

The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical ***,it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number ***,the interference problems between two stages and big stress concentration are *** crown surface configuration technology and structure design were introduced to optimize the meshing *** improve the double crown design feasibility and meshing stability,it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various influence factors on the contact condition and quasi-static characteristics of multistage face gears *** relevant scatter plots are fitted by comparing the contact results with different crown quantities and friction coefficients to intuitively obtain the variation regularity of maximum deformation,maximum strain,maximum stress and maximum strain *** natural frequency and mode coefficient are also determined by modal analysis under these two *** the above mentioned studies verified the contact conjugate properties of double crown surface configuration were *** results can provide a foundation for structure optimization and transmission reliability of multistage face gears.

关键词： Multistage face gears quasi-static contact characteristics modal characteristics double crown surface simulation analysis.