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冬小麦条锈病单叶光谱特性及严重度反演 被引量:39
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作者 黄木易 黄文江 +4 位作者 刘良云 黄义德 王纪华 赵春江 万安民 《农业工程学报》 EI CAS CSCD 北大核心 2004年第1期176-180,共5页
对冬小麦条锈病胁迫不同严重度(0、1%、10%、20%、30%、45%、60%和80%)的单叶进行光谱测定,其光谱特征明显,随严重度增加,单叶光谱反射率在可见光550~740nm处增加,差异显著;而近红外平台750~1340nm反射率也呈上升趋势,差异不显著;中红... 对冬小麦条锈病胁迫不同严重度(0、1%、10%、20%、30%、45%、60%和80%)的单叶进行光谱测定,其光谱特征明显,随严重度增加,单叶光谱反射率在可见光550~740nm处增加,差异显著;而近红外平台750~1340nm反射率也呈上升趋势,差异不显著;中红外1350~1600nm反射率上升,差异显著。反射率与严重度相关系数在376~1600nm范围内基本成正相关,达到极显著相关的敏感波段区域为446~725nm与1380~1600nm。入选了493、666nm和1430nm与严重度的相关系数最高的单个波段,利用相关性最好的666nm和相关性最弱的758nm波段组合设计了光谱角度指数SAI(SpectralAngleIndex),与严重度建立的模型相关系数较高。并利用连续统去除法对540~740nm特征反射峰进行归一化定量分析,吸收深度(Depth)与吸收面积(Area)与严重度呈极显著相关,设计的吸收面积指数AAI(AbsorptionAreaIndex)与严重度相关系数最好,可较好地反演单叶严重度。结果表明,条锈病单叶光谱特性明显,利用其光谱反射率可以很好的估算单叶严重度,建立的模型具有很高的反演精度。结果对深入研究冬小麦条锈病害遥感监测机理提供了理论依据。 展开更多
关键词 积分球 冬小麦条锈病 单叶光谱特性 光谱角度指数 吸收面积指数 严重度反演
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不同施氮水平辣椒单叶光谱特征及SPAD值与叶绿素含量的相关性 被引量:12
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作者 唐恒朋 钱晓刚 +4 位作者 李莉婕 岳延滨 黎瑞君 聂克艳 赵泽英 《西南农业学报》 CSCD 北大核心 2016年第10期2324-2329,共6页
为及时、准确无损地估测辣椒叶绿素含量,获取辣椒长势,通过田间试验,分析2个辣椒品种不同氮肥水平下辣椒单叶反射光谱、SPAD值与叶绿素含量的相关性。结果表明:果实膨大期和盛果期叶绿素含量的特征波段长辣6号为680和2026 nm,火焰山为36... 为及时、准确无损地估测辣椒叶绿素含量,获取辣椒长势,通过田间试验,分析2个辣椒品种不同氮肥水平下辣椒单叶反射光谱、SPAD值与叶绿素含量的相关性。结果表明:果实膨大期和盛果期叶绿素含量的特征波段长辣6号为680和2026 nm,火焰山为360和1349 nm,特征波段下光谱反射率与叶绿素含量之间的相关系数|r|分别为0.961、0.994、0.891和0.678(P<0.01)。不同品种辣椒叶片SPAD值与叶绿素含量(叶绿素a、叶绿素b、叶绿素总量)间存在正相关关系,相关性强弱均表现为长辣6号>火焰山。SPAD值与叶绿素a、叶绿素b和叶绿素总量之间的相关系数长辣6号为0.66、0.69和0.68(P<0.01),火焰山为0.39、0.36和0.41(P<0.05)。 展开更多
关键词 辣椒 氮素 SPAD 叶绿素 单叶光谱
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棉花蚜虫单叶高光谱特征识别研究 被引量:4
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作者 卢小燕 《新疆农垦科技》 2010年第6期32-35,共4页
本文在棉花蚜虫危害主要生育时期测试不同严重度的蚜虫危害单叶光谱,分析并比较了不同时期、不同严重度棉蚜危害单叶光谱反射率特征,确定了其敏感波段,并建立了相应的估测模型。结果表明:棉花蚜虫单叶光谱特征明显,不同时期蚜虫单叶光... 本文在棉花蚜虫危害主要生育时期测试不同严重度的蚜虫危害单叶光谱,分析并比较了不同时期、不同严重度棉蚜危害单叶光谱反射率特征,确定了其敏感波段,并建立了相应的估测模型。结果表明:棉花蚜虫单叶光谱特征明显,不同时期蚜虫单叶光谱反射率在可见光区均表现出先升后降的特征,近红外波段则表现出相同的趋势。434~727 nm可作为棉叶蚜虫的敏感波段,648 nm可作为棉叶蚜虫的最佳波段。基于敏感波段建立的棉蚜叶片遥感估测模型均达到显著相关水平,其中波段组合1 589-648/1 589+648建立的估算模型估算精度最高,均方根误差最小,RMSE为1.198,可作为棉叶蚜虫严重度的最佳识别模型。该研究为遥感监测棉花蚜虫光谱提供了理论依据及参考。 展开更多
关键词 棉花 蚜虫 单叶光谱
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Preparation of a halogen-free P/N/Si flame retardant monomer with reactive siloxy groups and its application in cotton fabrics 被引量:2
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作者 Peihua Zhao Kuankuan Xiong +1 位作者 Wentao Wang Yaqing Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第9期1322-1328,共7页
A novel halogen-free phosphorus–nitrogen–silicon flame retardant monomer with reactive siloxy groups,N-(diphenylphosphino)-1,1-diphenyl-N-(3-(triethoxysilyl)propyl) phosphinamine(DPTA) has been synthesized and was a... A novel halogen-free phosphorus–nitrogen–silicon flame retardant monomer with reactive siloxy groups,N-(diphenylphosphino)-1,1-diphenyl-N-(3-(triethoxysilyl)propyl) phosphinamine(DPTA) has been synthesized and was applied to the fire-resistant finishing of cotton fabrics. The molecular structure of DPTA has been well characterized by elemental analysis, FTIR,1H NMR, and ^(31)P NMR spectroscopies. The chemically-grafted cotton fabrics, which were treated with 25 wt% DPTA, were obtained and confirmed by attenuated total reflectance Fourier infrared spectroscopy(ATR-FTIR). The flame retardancy and thermal property of the treated samples were investigated by limited oxygen index(LOI), vertical flammability test(VFT), thermogravimetric analysis(TGA) and microscale combustion calorimeter(MCC). It is noted that in vertical flammability test, the treated samples extinguished immediately upon removing the ignition source, whereas the untreated one was completely burned out. Furthermore, TGA and MCC tests revealed that the treated samples produced a high char formation and a low heated release during combustion. The surface morphology of the untreated and treated samples and the char residues after LOI tests were observed by scanning electron microscopy(SEM). Therefore, all the results showed that the treated cotton fabrics with 25 wt% DPTA apparently improved the fireresistant and thermal performances. 展开更多
关键词 P/N/Si flame retardant Synthesis Cotton fabrics Flame retardancy
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Study on the ultraviolet-visible spectral feature of tobacco leaves by pattern recognition
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作者 RUAN Chun-sheng XU Chang-liang +5 位作者 ZHANG Ge FAN Jing LI Yu-zhong WANG Xiao-xia FANG Li CHEN Sui-yun 《Journal of Life Sciences》 2009年第9期34-42,53,共10页
In order to differentiate regions, varieties, and parts of tobacco leaves, two pattern recognition methods through pattern classification modeling were developed based on the comprehensive information of ultraviolet-v... In order to differentiate regions, varieties, and parts of tobacco leaves, two pattern recognition methods through pattern classification modeling were developed based on the comprehensive information of ultraviolet-visible spectroscopy (UV-VIS) by employing one-way analysis of variance (ANOVA1) and wave range random combination (WRRC) technology from MATLAB. This proposed classification method has never been reported previously and the instrument and operation for this method is much more convenient and efficient than previous reported classification methods. The result of this paper demonstrated that the spectral features extracted by ANOVAI and WRRC methods could be used to differentiate tobacco leaves with different patterns. The ANOVAI method had a training recognition rate range of 75.00-87.50%,4 and a validation recognition rate range of 57.14-100%. The WRRC method had a training recognition rate range of 75.00-94.12% and a validation recognition rate range of 66.67-100%. The ANOVAI method is more convenient and efficient in model developing, while the WRRC method utilizes fewer model variables and is more robust. 展开更多
关键词 Nicotiana tabacum ultraviolet-visible spectroscopy (UV-VIS) pattern recognition spectral feature DIFFERENTIATION
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