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傅里叶变换近红外光谱法测定大麦中蛋白质、淀粉和赖氨酸含量 总被引:13,自引:0,他引:13
采用傅里叶变换近红外光谱法测定大麦中蛋白质、淀粉、赖氨酸的含量,并用光谱影响值法(leverage)对异常值进行判断和处理。蛋白质、淀粉和赖氨酸含量近红外光谱分析模型的测定系数R。分别为0.985、0.973和0.978;检验集的化学值与模型预测值的相关系数r分别为0.9853、0.9644和0.9172,分析模型的预测相对标准偏差RSD分别为4.0%、2.4%和5.4%,该结果可替代经典分析方法,满足农产品快速分析的需要。 相似文献
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测量了含微量甲醇(体积分数为0.04%~0.24%)的系列乙醇水溶液的近红外光谱,利用近红外光谱分析建立了预测甲醇含量的定量分析模型。比较了用外部检验法(Test Set-Validation)和交叉检验法(Cross-Validaton)建立的数学模型,研究了使用外部检验法时,校正集和检验集样品数的改变对模型预测结果的影响。结果发现,当校正集样品数为15检验集样品数为6(总样品数为21)时,使用外部检验法建立的数学模型预测结果较好,其校正集的均方根误差和检验集的预测均方根误差(分别为RMSEE和RMSEP)均较小(分别为0.0115和0.0105),而且很接近。结果表明,近红外光谱方法简单,准确而且实用。 相似文献
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以普通玉米籽粒为试验材料,应用偏最小二乘回归法建立了基于近红外光谱数据的测定玉米籽粒中淀粉含量的校正模型。校正模型的校正误差(RMSEC)、交叉检验误差(RMSECV)和预测误差(RMSEP)分别#30.31%、0.42%和0.29%,校正数据集和独立的检验数据集的预测值与实际测定值之间的相关系数分别达到0.9255和0.9310,表明所建立的校正模型具有较高的预测精度和较好的推广性,为玉米籽粒中淀粉含量的快速、无损测定提供了新的途径: 相似文献
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离散小波变换-遗传算法-交互检验法用于近红外光谱数据的高倍压缩与变量筛选 总被引:11,自引:0,他引:11
用遗传算法(GA)与交互检验(CV)相结合建立了一种用于对近红外光谱(NIR)数据及其离散小波变换(DWT)系数进行变量筛选的方法,并应用于烟草样品中总挥发碱和总氮的同时测定。结果表明:NIR数据经DWT压缩为原始大小的3.3%时基本没有光谱信息的丢失;有效的变量筛选可以极大地减少模型中的变量个数,降低模型的复杂程度,改善预测的准确度。 相似文献
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应用正交试验设计法,以测定胺类燃料中水分为实例进行近红外光谱(NIR)建模参数的优化选择。以样本集划分方法、校正集比例、光谱预处理方法和波段选择等作为因素进行正交设计,分别建立校正模型,以验证集的标准预测偏差(SEP)为正交试验结果。通过正交试验结果分析,确定最佳建模参数,并且围绕最大影响因素进行优化调整,使预测模型的稳健性和测量结果的准确性得到提高。 相似文献
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建立使用近红外光谱法(NIR)快速测定溶剂型木器涂料稀释剂中甲苯、乙苯、对二甲苯、间二甲苯和邻二甲苯等苯系物含量方法。收集涂料稀释剂样品,使用气相色谱法(GC)测定苯系物含量,并采集其近红外光谱信息,采用偏最小二乘法(PLS)建立NIR光谱与苯系物含量的线性关系模型。苯系物校正均方差(RMSEC)在(0.47~1.40)%之间、相关系数(R2)在0.956~0.988之间;预测均方差(RMSEP)在(0.73~2.32)%之间、相关系数(R2)在0.951~0.986之间。NIR模型预测效果良好,定量方法快速、简单、准确,可在检测涂料的有毒有害物质中推广应用。 相似文献
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建立了使用近红外光谱法(NIR)快速测定溶剂型木器涂料中甲苯、乙苯和二甲苯的方法。收集涂料样品,使用气相色谱法(GC)测定苯系物含量。采用聚乙烯密实袋封装聚氨酯类、硝基类或醇酸类涂料,应用积分球透漫射采样方式采集清漆和漫射采样方式采集色漆的近红外光谱。采用偏最小二乘法,分别建立清漆和色漆的近红外光谱与苯系物线性关系模型。校正集均方差在0.43%~1.32%之间、相关系数R在0.9046~0.9766之间。验证集均方差在0.591%~1.73%之间。对未知样品预测,清漆样品预测值相对偏差<15%;色漆样品预测值相对偏差<20%。两个定量模型预测效果良好。该2个NIR定量方法适用于对溶剂型木器涂料中甲苯、乙苯和二甲苯含量进行快速测定。 相似文献
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采用近红外(NIR)光谱技术和最小二乘支持向量机(LSSVM)参数优化方法,建立定标预测模型测定鱼粉灰分的含量,采用去趋势校正和标准正交校正(DC-SNV)相结合的方式进行光谱预处理,基于网格搜索法建立LSSVM的参数优化模型,提高NIR光谱定量分析的预测精度。结果表明,LSSVM参数网格搜索方法能够有效地应用于鱼粉NIR光谱模型优化,获得的鱼粉灰分的光谱预测值与化学测定值能较准确的匹配,有利于NIR光谱技术快速检测在养殖饲料产品中的应用。 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
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用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
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Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu0 as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than CuI in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT). 相似文献
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George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine. 相似文献