目的探究后装治疗中使用环型施源器导致放射源驻留位置产生的偏差值。方法收集2016年2月至2020年10月中国香港大学深圳医院放疗科瓦里安Gamma Med Plus后装治疗系统中应用钛制环型施源器创建验证计划资料,通过放射自显影胶片得到放射源...目的探究后装治疗中使用环型施源器导致放射源驻留位置产生的偏差值。方法收集2016年2月至2020年10月中国香港大学深圳医院放疗科瓦里安Gamma Med Plus后装治疗系统中应用钛制环型施源器创建验证计划资料,通过放射自显影胶片得到放射源实际驻留位置,将其与计划驻留位置比较后得到两者的偏差数据。结果使用环型施源器时,放射源实际驻留位置与计划驻留位置存在一定的偏差值,其中30°环型施源器平均偏差为-1.42 mm,45°环型施源器平均偏差为-1.82 mm,60°环型施源器平均偏差为-1.85 mm。结论为适应精准放疗的发展趋势,有必要对后装环型施源器放射源位置偏差值进行验证,并应用相应的修正值修正偏差。展开更多
为进一步明确中国绥芬河三块鱼属(Tribolodon)鱼类的分类地位及其起源,本研究依据表型和洄游产卵时间,将珠星三块鱼(Tribolodon hakonensis)、三块鱼(T.brandtii)及二者疑似杂交种与日本珠星三块鱼共53尾样本的COI基因序列进行了分析和...为进一步明确中国绥芬河三块鱼属(Tribolodon)鱼类的分类地位及其起源,本研究依据表型和洄游产卵时间,将珠星三块鱼(Tribolodon hakonensis)、三块鱼(T.brandtii)及二者疑似杂交种与日本珠星三块鱼共53尾样本的COI基因序列进行了分析和比较。COI有效序列长度为637 bp,共检测到8种单倍型,其中三块鱼独享4种、珠星三块鱼独享3种、日本珠星三块鱼独享1种;疑似杂交种虽与三块鱼共享2种单倍型,却有80%的个体的单倍型与珠星三块鱼主效单倍型一致。系统进化分析显示,珠星三块鱼与珠星三块鱼南方型(sourthern forms of T.hakonensis)聚为一支,日本珠星三块鱼与珠星三块鱼北方型(northern forms of T.hakonensis)聚为一支,三块鱼(T.brandtii)单独聚为一支,由此可以确定日本海大彼得湾经俄罗斯滨海区溯河到中国河区产卵的三块鱼实为珠星三块鱼南方型和三块鱼。遗传距离结果显示,珠星三块鱼南方型和北方型的遗传距离为0.023,符合COI类群间的划分依据(>0.02),支持将它们划分为两个有效种或亚种更妥当。依据COI分析结果,推测珠星三块鱼南方型和三块鱼存在杂交的可能性,提出了三块鱼野生种质资源保护和合理利用的相关建议。展开更多
针对农田中高分辨率空间模式蒸散量(ET)缺少有效量化的问题,提出一种基于无人机(UAV)估算农田蒸散量的方法。构建了M100型多旋翼无人机搭载FLIR VueProR热像仪和Micasense RedEdge多光谱成像仪的采集数据平台;将无人机数据匹配卫星遥感...针对农田中高分辨率空间模式蒸散量(ET)缺少有效量化的问题,提出一种基于无人机(UAV)估算农田蒸散量的方法。构建了M100型多旋翼无人机搭载FLIR VueProR热像仪和Micasense RedEdge多光谱成像仪的采集数据平台;将无人机数据匹配卫星遥感蒸散模型,比较典型单层模型METRIC(Mapping evapotranspiration at high resolution with internalized calibration)模型和典型双层模型RSEB(Remote sensing energy balance)模型在农田中的适用程度;针对RSEB模型的土壤热通量计算方式不适用于农田环境的问题,对模型进行基于多光谱数据的改进;针对模型中温度参数易产生较大误差的问题,基于无人机热像仪数据与实际温度间的关系,对获取的热像仪数据进行校正;将模型计算值与涡度相关系统(OPEC)测量值进行对比。结果表明,结合无人机多光谱数据的RSEB模型经过温度校正可得到结果较为准确的通量数据,显热通量均方根误差为20.013 W/m^2,平均绝对误差为15.835 W/m^2,潜热通量均方根误差为40.202 W/m^2,平均绝对误差为26.017 W/m^2,进而得到分米级分辨率的农田蒸散量空间分布图。本文估算方法可以有效获取高分辨率空间模式的田间蒸散量,为精准农业灌溉提供技术支持。展开更多
Accurate data acquisition and analysis to obtain crop canopy information are critical steps to understand plant growth dynamics and to assess the potential impacts of biotic or abiotic stresses on plant development.A ...Accurate data acquisition and analysis to obtain crop canopy information are critical steps to understand plant growth dynamics and to assess the potential impacts of biotic or abiotic stresses on plant development.A versatile and easy to use monitoring system will allow researchers and growers to improve the follow-up management strategies within farms once potential problems have been detected.This study reviewed existing remote sensing platforms and relevant information applied to crops and specifically grapevines to equip a simple Unmanned Aerial Vehicle(UAV)using a visible high definition RGB camera.The objective of the proposed Unmanned Aerial System(UAS)was to implement a Digital Surface Model(DSM)in order to obtain accurate information about the affected or missing grapevines that can be attributed to potential biotic or abiotic stress effects.The analysis process started with a three-dimensional(3D)reconstruction from the RGB images collected from grapevines using the UAS and the Structure from Motion(SfM)technique to obtain the DSM applied on a per-plant basis.Then,the DSM was expressed as greyscale images according to the halftone technique to finally extract the information of affected and missing grapevines using computer vision algorithms based on canopy cover measurement and classification.To validate the automated method proposed,each grapevine row was visually inspected within the study area.The inspection was then compared to the digital assessment using the proposed UAS in order to validate calculations of affected and missing grapevines for the whole studied vineyard.Results showed that the percentage of affected and missing grapevines was 9.5%and 7.3%,respectively from the area studied.Therefore,for this specific study,the abiotic stress that affected the experimental vineyard(frost)impacted a total of 16.8%of plants.This study provided a new method for automatically surveying affected or missing grapevines in the field and an evaluation tool for plant growth conditions,which can be implemented for other uses such as canopy management,irrigation scheduling and other precision agricultural applications.展开更多
文摘为进一步明确中国绥芬河三块鱼属(Tribolodon)鱼类的分类地位及其起源,本研究依据表型和洄游产卵时间,将珠星三块鱼(Tribolodon hakonensis)、三块鱼(T.brandtii)及二者疑似杂交种与日本珠星三块鱼共53尾样本的COI基因序列进行了分析和比较。COI有效序列长度为637 bp,共检测到8种单倍型,其中三块鱼独享4种、珠星三块鱼独享3种、日本珠星三块鱼独享1种;疑似杂交种虽与三块鱼共享2种单倍型,却有80%的个体的单倍型与珠星三块鱼主效单倍型一致。系统进化分析显示,珠星三块鱼与珠星三块鱼南方型(sourthern forms of T.hakonensis)聚为一支,日本珠星三块鱼与珠星三块鱼北方型(northern forms of T.hakonensis)聚为一支,三块鱼(T.brandtii)单独聚为一支,由此可以确定日本海大彼得湾经俄罗斯滨海区溯河到中国河区产卵的三块鱼实为珠星三块鱼南方型和三块鱼。遗传距离结果显示,珠星三块鱼南方型和北方型的遗传距离为0.023,符合COI类群间的划分依据(>0.02),支持将它们划分为两个有效种或亚种更妥当。依据COI分析结果,推测珠星三块鱼南方型和三块鱼存在杂交的可能性,提出了三块鱼野生种质资源保护和合理利用的相关建议。
文摘针对农田中高分辨率空间模式蒸散量(ET)缺少有效量化的问题,提出一种基于无人机(UAV)估算农田蒸散量的方法。构建了M100型多旋翼无人机搭载FLIR VueProR热像仪和Micasense RedEdge多光谱成像仪的采集数据平台;将无人机数据匹配卫星遥感蒸散模型,比较典型单层模型METRIC(Mapping evapotranspiration at high resolution with internalized calibration)模型和典型双层模型RSEB(Remote sensing energy balance)模型在农田中的适用程度;针对RSEB模型的土壤热通量计算方式不适用于农田环境的问题,对模型进行基于多光谱数据的改进;针对模型中温度参数易产生较大误差的问题,基于无人机热像仪数据与实际温度间的关系,对获取的热像仪数据进行校正;将模型计算值与涡度相关系统(OPEC)测量值进行对比。结果表明,结合无人机多光谱数据的RSEB模型经过温度校正可得到结果较为准确的通量数据,显热通量均方根误差为20.013 W/m^2,平均绝对误差为15.835 W/m^2,潜热通量均方根误差为40.202 W/m^2,平均绝对误差为26.017 W/m^2,进而得到分米级分辨率的农田蒸散量空间分布图。本文估算方法可以有效获取高分辨率空间模式的田间蒸散量,为精准农业灌溉提供技术支持。
基金the National Natural Science Foundation of China(No.41401391)the Fundamental Research Funds for the Central Universities of China(No.2014YB071)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,and the Exclusive Talent Funds of Northwest A&F University of China(No.2013BSJJ017).
文摘Accurate data acquisition and analysis to obtain crop canopy information are critical steps to understand plant growth dynamics and to assess the potential impacts of biotic or abiotic stresses on plant development.A versatile and easy to use monitoring system will allow researchers and growers to improve the follow-up management strategies within farms once potential problems have been detected.This study reviewed existing remote sensing platforms and relevant information applied to crops and specifically grapevines to equip a simple Unmanned Aerial Vehicle(UAV)using a visible high definition RGB camera.The objective of the proposed Unmanned Aerial System(UAS)was to implement a Digital Surface Model(DSM)in order to obtain accurate information about the affected or missing grapevines that can be attributed to potential biotic or abiotic stress effects.The analysis process started with a three-dimensional(3D)reconstruction from the RGB images collected from grapevines using the UAS and the Structure from Motion(SfM)technique to obtain the DSM applied on a per-plant basis.Then,the DSM was expressed as greyscale images according to the halftone technique to finally extract the information of affected and missing grapevines using computer vision algorithms based on canopy cover measurement and classification.To validate the automated method proposed,each grapevine row was visually inspected within the study area.The inspection was then compared to the digital assessment using the proposed UAS in order to validate calculations of affected and missing grapevines for the whole studied vineyard.Results showed that the percentage of affected and missing grapevines was 9.5%and 7.3%,respectively from the area studied.Therefore,for this specific study,the abiotic stress that affected the experimental vineyard(frost)impacted a total of 16.8%of plants.This study provided a new method for automatically surveying affected or missing grapevines in the field and an evaluation tool for plant growth conditions,which can be implemented for other uses such as canopy management,irrigation scheduling and other precision agricultural applications.
