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利用光谱技术分析北京地区农业土壤重金属光谱特征 总被引：9，自引：0，他引：9
采用ASD光谱仪测量111个北京地区农业土壤样本光谱曲线基础上,利用光谱分析的方法探索北京地区农业土壤中8种土壤重金属(Cr、Ni、Cu、Zn、As、Cd、Pb、Hg)含量与可见-近红外光谱反射率的相关关系,分析土壤重金属的光谱特征,为基于遥感光谱监测土壤重金属含量提供基础。主成分分析和光谱变量与土壤重金属相关分析的研究结果表明,一阶微分光谱最适于获取土壤中的重金属元素信息,并且土壤重金属含量与反射光谱之间存在显著相关关系,最高相关系数达到а=0.01水平显著相关,中心波长在415~570 nm以及大于950 nm的光谱部分是土壤重金属特征光谱的主要分布范围。 相似文献
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S.G. Gordon M.W. Miller R.M. Roland A.B. Saunders S.E. Achen L.T. Drourr D.A. Nelson 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2009,23(5):995-1002
Background: Transcatheter atrial septal defect (ASD) closure in the dog was first reported in 2005.
Objectives: Describe the technique and both short- and mid-term outcome of transcatheter ASD closure with the Amplatzer® atrial septal occluder (ASO).
Animals: Thirteen client-owned dogs with ASD.
Methods: Records of the initial 13 dogs in which transcatheter ASD closure was attempted at Texas A&M University were reviewed.
Results: All dogs had hemodynamically relevant septum secundum ASD. Two dogs had concurrent congenital abnormalities. ASOs were deployed in 13 dogs and released in 12. Eleven were released by a right jugular approach and 1 by a transatrial approach through a right lateral thoracotomy. Transthoracic echocardiographic estimates of ASD size were 14.0 ± 5.4 mm (mean ± 1 standard deviation) with a range of 7–22 mm. Accidental right atrial release occurred in 1 dog and embolization after release occurred in 2 dogs. Transcatheter ASD closure was successful in 10 dogs. Transthoracic color Doppler echocardiography the day after ASD closure indicated complete occlusion in 5 dogs, trivial to mild residual shunting in 4 dogs, and moderate residual shunting in 1 dog. Follow-up echocardiograms (mean of 12.4 ± 7.4 months postprocedure) were available for 9 dogs. There was no residual ASD shunting in 6 dogs. In 3 of the 5 dogs with postoperative residual shunting it was judged to be decreased and hemodynamically unimportant relative to the dogs' postoperative evaluations. The mean length of event-free survival in the 10 dogs that underwent successful transcatheter ASD closure was 22.2 ± 10.2 months. 相似文献
Objectives: Describe the technique and both short- and mid-term outcome of transcatheter ASD closure with the Amplatzer
Animals: Thirteen client-owned dogs with ASD.
Methods: Records of the initial 13 dogs in which transcatheter ASD closure was attempted at Texas A&M University were reviewed.
Results: All dogs had hemodynamically relevant septum secundum ASD. Two dogs had concurrent congenital abnormalities. ASOs were deployed in 13 dogs and released in 12. Eleven were released by a right jugular approach and 1 by a transatrial approach through a right lateral thoracotomy. Transthoracic echocardiographic estimates of ASD size were 14.0 ± 5.4 mm (mean ± 1 standard deviation) with a range of 7–22 mm. Accidental right atrial release occurred in 1 dog and embolization after release occurred in 2 dogs. Transcatheter ASD closure was successful in 10 dogs. Transthoracic color Doppler echocardiography the day after ASD closure indicated complete occlusion in 5 dogs, trivial to mild residual shunting in 4 dogs, and moderate residual shunting in 1 dog. Follow-up echocardiograms (mean of 12.4 ± 7.4 months postprocedure) were available for 9 dogs. There was no residual ASD shunting in 6 dogs. In 3 of the 5 dogs with postoperative residual shunting it was judged to be decreased and hemodynamically unimportant relative to the dogs' postoperative evaluations. The mean length of event-free survival in the 10 dogs that underwent successful transcatheter ASD closure was 22.2 ± 10.2 months. 相似文献
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以云南省香格里拉市为研究区,对ASD光谱仪实测的4种针叶树种光谱数据采用包络线去除法、光谱一阶微分法和光谱二阶微分法3种波段选择方法得到Hyperion高光谱影像数据的分类特征波段,采用最大似然法、支持向量机2种分类方法对所选的特征波段开展树种识别分类,对原始影像采用光谱角填图分类方法作对比实验。结果表明,基于ASD数据的光谱一阶波段选择方案的支持向量机分类方法精度最高,总体分类精度为81.95%,Kappa系数为0.725 1。采用ASD实测光谱数据能有效指导Hyperion进行树种分类,基于数据尺度和换算方式,一阶微分更适合特征波段选择;与传统的数理统计分类方法和光谱特征分类方法相比,基于机器学习的方法如支持向量机等在高光谱遥感分类中具有更大的应用潜力。 相似文献
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土壤厌氧消毒(anaerobic soil disinfestation,ASD)技术作为一种环境友好的非化学土壤消毒技术能有效防治真菌、细菌、线虫和杂草等引起的土传病害。该技术已在多个国家广泛应用并被证实可显著增加作物产量。ASD技术基本流程为向土壤中添加适量有机碳源、补充足够水分和用塑料薄膜覆膜密闭2～15周。ASD技术对土传病害防控的作用机理为有机碳源分解产生的挥发性有机物对土传病原菌有抑制作用,土壤理化指标的改变(如pH降低、有机质增加等)能提升土壤质量,从而提高作物抗逆能力,土壤厌氧条件促进土壤微生物群落结构及多样性的改变,通过生物竞争和结构重建改善土壤微生态环境,降低土传病害发生风险。ASD技术对土传病害的防治效果也因有机碳源类别、土壤理化性质及覆盖薄膜的不同而存在差异。因此,优化ASD技术试验条件、深入探索ASD技术作用机理、挖掘更多有灭菌活性的挥发性物质或有益生防菌是未来ASD技术的研究重点。同时,ASD技术与其他土壤消毒技术结合使用,有助于提高其防治效果,扩大应用范围。 相似文献
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土壤厌氧消毒对青枯病的控制及土壤细菌群落结构的影响 总被引：1，自引：0，他引：1
近年来,土壤厌氧消毒(Anaerobic soil disinfestation,ASD)作为一种非化学、环境友好型土壤消毒方法,在缓解连作障碍和防治土传病害方面具有显著效果,但其作用机理尚不完全清楚。本研究设置6个处理,即对照、添加米糠(DRB)、麦麸(DWB)、茶麸(DTB)、秸秆(DRS)和不添加物料(D)5种土壤厌氧消毒处理,分析不同处理对青枯病防控效果、土壤理化性质及土壤细菌群落结构组成及多样性的影响。结果表明,与CK相比,添加4种物料厌氧消毒处理对青枯病的防效均达100%,单纯厌氧处理防效为83.3%,且除了DRB外各厌氧处理均能大幅度促进番茄生长。各ASD能显著提高土壤温度、p H和电导率,降低Eh和土壤青枯菌数量。田间试验表明,与CK相比,ASD的番茄青枯病发病率降低29.4%~42.7%,产量增加2.5倍~4.7倍。利用16S r DNA对土壤测序表明,ASD降低了土壤细菌α多样性指数,不同处理间土壤细菌物种种类、丰富度及多样性均存在显著差异。添加不同有机物料的ASD厚壁菌门(Firmicutes)相对丰度大幅度提高,成为优势群落;该门中的厌氧型细菌梭菌科(Clostridiaceae)、瘤胃菌科(Ruminococcaceae)和耐受性细菌芽孢杆菌科(Bacillaceae)等相对丰度也大幅度提高。本研究表明,土壤厌氧消毒处理显著改变了土壤细菌群落结构组成及多样性,厌氧和耐受型细菌丰度大幅度增加,这可能是ASD防控土传病害青枯病的作用机理之一。 相似文献
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利用从土壤中分离筛选出的1株高效拮抗辣椒疫病的真菌ASD菌株,采用含毒介质菌碟法进行抑菌试验,优化不同培养基配方(包括碳源、氮源、无机盐离子)及发酵条件(包括发酵时间、温度、pH、转数、装液量),并利用单因子试验结果进行正交试验,以得到最佳抑菌效果的优组合。单因子试验结果表明,最佳营养成分为葡萄糖、甘氨酸、0.1 g/L KCl及MgSO4.7H2O、0.05 g/L FeSO4,最佳培养条件为pH 6、25℃、220 r/min、30 mL/100mL;正交试验结果表明,pH影响最大、氮源影响最小,根据K值得出发酵最优组合为葡萄糖、甘氨酸、0.03 g/L FeSO4、pH 6、于30℃180 r/min摇床培养5 d。 相似文献
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基于成像光谱仪的冬小麦苗期冠层叶绿素密度监测 总被引：9，自引：1，他引：9
利用自主研发的MSI200型成像光谱仪对冬小麦苗期叶绿素密度进行遥感监测, 并与ASD Fieldspc FR2500型非成像地物光谱仪测定数据相比。结果表明, 两种仪器所得R720、FD660、FD550、TCARI、GNDVI、PPR(550, 450)、NRI等光谱特征参量均与叶绿素密度显著相关, 拟合度较高, 说明MSI200型成像光谱仪测定的作物光谱数据是可靠的。对筛选出的模型进行检验, ASD Fieldspc FR2500模型的预测精度达86.61%~92.79%, MSI200达91.26%~95.54%, 其中PPR对叶绿素密度预测精度最高, RMSE分别为0.8391和0.0979。与传统非成像地物光谱仪相比, 成像光谱仪能够提取纯冠层光谱信息, 所得模型精度高、误差小, 筛选的植被指数和特征波段对于航天、航空遥感器的定标有重要意义。 相似文献
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为探究地面高光谱遥感监测不同光谱尺度对水稻重金属胁迫区分度,以不同污染水平地面ASD高光谱数据为基础,通过光谱敏感特征优选确定450～900 nm为水稻重金属胁迫敏感波段,利用DB5小波变换产生的多尺度小波特征系数模拟不同光谱分辨率,结合小波参数的信息熵特征和分形维数特征,对水稻重金属胁迫特征光谱尺度进行识别,通过构建胁迫相关的叶绿素光谱指数 MCARI/OSAVI、NDSI_R、Depth验证所识别的特征尺度的可靠性和精准性。结果表明：①小波分解各尺度细节系数计算出的信息熵在分解的5～7尺度附近不同胁迫水平有明显的特征转折点;②随着分解尺度的增加,不同胁迫水平的分维数差异值变小,第5尺度是水稻受不同重金属胁迫8层尺度分解和重构下光谱曲线尺度的最明显的转折点,在尺度5下,光谱曲线的峰谷细节得到更好的反映; ③研究水稻重金属污染光谱特征尺度既保留光谱信息的主要特征,又最大程度的减少了光谱数据量,不仅提高了水稻重金属污染监测的效率而且为环境监测提供了新的手段。 相似文献