用人工神经网络-近红外光谱法测定冬虫夏草中的甘露醇

提出了用近红外漫反射光谱技术快速分析发酵冬虫夏草菌粉中甘露醇含量的新方法。采用比色法测定样品中的甘露醇，其含量范围为8．082％-14．548％。在7501．7-6097．8cm^-1与5453．7-4246．5cm^-1波段，分别采用PCR、PLSR和BP神经网络方法建立了样品近红外光谱的一阶微分光谱与其甘露醇含量之间的相关模型。BP神经网络模型的内部交叉验证误差均方根为0．475，预测误差均方根为0．608，均优于PCR和PLSR的处理结果。这表明，BP神经网络法对非线性检测对象具有较好的建模效果，可用于中药近红外光谱分析的非线性校正。     

不同方法预处理的玉米秸秆结构与酶解分析

在利用秸秆进行工业转化时,因为秸秆结构复杂,导致转化效率低,所以需对秸秆进行预处理,破坏秸秆复杂结构,提高转化效率。采用扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)和X射线衍射技术分析不同预处理方式对玉米秸秆微观结构的影响,并利用纤维素酶对不同预处理秸秆进行酶解,评价预处理效果。扫描电镜结果表明,不同预处理方式对秸秆表面形态和秸秆整体结构造成不同程度的破坏,其中NaOH预处理后的秸秆表面结构坍塌明显,表明木质纤维素结构被有效打破。利用傅里叶变换红外光谱对不同预处理方式的秸秆进行分析,其中1600和1510cm~(-1)为木质素的特征峰,NaOH预处理后的秸秆在此处的特征峰基本消失,表明NaOH预处理对秸秆木质素的去除效率比较明显。1744~1734 cm~(-1)为C=O伸缩振动特征峰,此峰的强度与木质素和半纤维素的含量有关,采用不同方法预处理后,此峰的吸收强度不同程度地减少,表明各种预处理方法不同程度地去除了秸秆的木质素和半纤维素。X-射线衍射分析表明,不同预处理后秸秆的结晶度均发生不同程度的改变,其中H_2SO_4预处理后秸秆的结晶度提高最大,达到43.4%。其中NaOH预处理秸秆后,用纤维素酶酶解60h,使其酶解产糖量达到33.32g/L。本研究分析了不同秸秆预处理方法的效果,为利用玉米秸秆生产生物化工产品提供了理论依据。     

CCD近红外光谱快速测定喷气燃料的冰点

从化学计量学角度研究了近红外光谱技术测定航空燃料冰点的原理．使用偏最小二乘法分别建立了短波近红外和长波近红外的航空燃料冰点快速测定模型．将近红外法冰点测定结果和标准方法（ＧＢ ２４３０—８１）测定结果进行了比较，两种结果吻合得很好（标准偏差为１．４７℃。），近红外光谱法具有分析精度高（标准偏差为０．５３℃），快速（单个样品分析时间为 ｌｍｉｎ）和操作方便的优点．实际分析结果表明，石油化工科学研究院研制的ＣＣＤ短波近红外光谱仪分析性能达到进口傅立叶近红外光谱仪水平。     

中药材三七中皂苷类成分的近红外光谱快速无损分析新方法

提出了用近红外漫反射光谱快速无损测定三七中皂苷类成分的新方法采用 HPLC分析了中药材三七固皂昔R_1,人参皂苷Hg_1,Rb_1和Rd的含量,用吸附树脂 比色法测定了三七总皂苷（PNS）的含量,共获得R_1,Bg_1,Rb_1,Rd,PNS的含 量范围分别为1,58-5．08,21,68-46.13,11.46-40.41粉．在3500-1100cm~(-1) 扫描样品,以交叉验证误差均方根（RMsECV）为指标,通过筛选,近红外波段和光 谱预处理方法．采用偏最小二乘算法建立了近红外光谱与5个组分PHLC分析值之间 的校正模型,预测了8个未知样本．R_1,Rg_1,Rb_1,Rd及PNS校正模型的RMSECV 分别为0．40,1.47,1.94,0RMSEP分别为0．53,3．15,2．14,0．70,9．03． 该方法快速无损,结果可靠,为中药材复杂体系中化学组分的测定提供了新的绿色 分析手段．     

应用近红外光谱和偏最小二乘回归法预测玉米中淀粉含量

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：     

近红外光谱法快速测定聚乙烯醇的醇解度

应用傅里叶变换近红外漫反射光谱技术,通过对光谱预处理方法的选择和模型优化,建立了准确度较好的聚乙烯醇醇解度近红外定量分析模型,并验证了其可行性。通过验证试验表明,其预测值接近于化学法测定值,适合聚乙烯醇醇解度快速测定。     

应用遗传算法和PLS的近红外光谱预测玉米中淀粉含量的研究

以普通玉米籽粒为试验材料,在应用遗传算法结合偏最小二乘回归法对近红外光谱数据进行特征波长选择的基础上,应用偏最小二乘回归法建立了特征波长测定玉米籽粒中淀粉含量的校正模型．试验结果表明,基于11个特征波长所建立的校正模型,其校正误差（RMSEC）、交叉检验误差（RMSECV）和预测误差（RMSEP）分别为0.30％、0.35％和0.27％,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0.9279和0.9390,与全光谱数据所建立的预测模型相比,在预测精度上均有所改善,表明应用遗传算法和PLS进行光谱特征选择,能获得更简单和更好的模型,为玉米籽粒中淀粉含量的近红外测定和红外光谱数据的处理提供了新的方法与途径．     

近红外光谱法同时测定多种雌、孕激素

研究并建立了用近红外吸收光谱同时测定多种雌、孕激素含量的快速方法,以四氢呋喃为溶剂,测定了雌二醇、雌三醇、雌酚酮,安宫黄体酮混合溶液的近红外光谱,利用雌,孕激素类物质在6000－11000cm^-1之间的近红外吸收,用偏最小二乘法解析重叠光谱,求得各组分的含曦,结果表明近外光谱法可以有效地同时检测雌二醇,雌三醇、雌酚酮和安宫黄体酮;并讨论了多种因素对测量精度的影响。     

基于近红外光谱和OPLS-DA的不同牌号卷烟分类识别方法研究

为了对卷烟牌号进行准确分类鉴别,提出了一种基于近红外光谱(NIRS)分析技术结合有监督的模式识别快速鉴别卷烟牌号的新方法。利用标准正态变量变换(SNV)、多元散射校正(MSC)、一阶导数(FD)、二阶导数(SD)和Savitzky-Golay平滑(SG)及其相结合的光谱预处理方法对烟丝光谱进行预处理,通过近红外光谱结合主成分分析(PCA)、偏最小二乘判别分析(PLS-DA)和正交偏最小二乘判别分析(OPLS-DA) 3种模式识别方法对不同牌号烟丝进行分类识别研究,并采用分类识别正确率作为评价指标。实验结果表明：(1)烟丝近红外光谱主成分得分图交叉重叠,区分不明显,PCA无法识别出5种牌号的成品烟丝;(2)烟丝光谱经MSC+FD预处理后的PLS-DA模型可得到较好的识别效果,校正集和测试集的分类识别正确率分别为100%和98.3%;(3)烟丝光谱经MSC+SD预处理后的OPLS-DA模型的模式识别效果最好,模型对自变量拟合指数(R2X）,因变量的拟合指数(R2Y)和模型预测指数(Q2)分别为0.485、0.907 和0.748,近红外光谱校正集和测试集的分类识别正确率均为100%。说明近红外光谱技术结合有监督模式识别方法OPLS-DA建立的烟丝牌号分类模型具有高效快速、准确无损的优点,为卷烟烟丝分类提供了一种新的快速鉴别方法。     

胆酸含量的近红外分析数学模型

本文应用近红外技术研究了快速测定胆酸含量的方法.通过测定胆酸在10000~4000cm-1范围内的近红外透射光谱,基于偏最小二乘(PLS)算法,建立了胆酸含量的数学模型.以校正均方差(RMSEC)和相关系数(R)为指标,确定了用于建模的最优近红外波段和光谱预处理方法,并基于此模型预测了9个样品.结果显示,建模效果良好,...     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

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.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

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.     

正丁胺对激光染料荧光谱影响的研究

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

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 Cu^I 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).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(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.