Structure and Two-dimensional Correlation Infrared Spectroscopy Study of a New One-dimensional Chain Compound: (4,4’-Hbpy)_3[NaMo_8O_(26)](4,4’- bpy)_2(H_2O)_4 (bpy = Bipydine)

A novel compound, （4,4＇-Hbpy）3[NaMo8O26]（4,4＇-bpy）2（H2O）4 1 （bpy=bipydine）, was synthesized by the hydrothermal method. Single-crystal X-ray diffraction shows that compound 1 belongs to the monoclinic system, space group C2/m with a=19.1921（5）, b=18.6931（6）, c=9.3821（3） A° β=104.8020（11）°, V=3254.22（17）A°^3 C50H51Mo8N10NaO30, Mr=2062.52, Z=2, F（000）=2016, μ=1.591 mm^-1 and Dc=2.105 g/cm^3. The final R=0.0283 and wR=0.0912 for 3118 observed reflections （I〉20（I））. Compound 1 contains the β-[Mo8O26]^4-anion, sodium ion, 4,4＇-bpy and lattice crystalline water molecules. The β-[MosO26] units link the sodium ion to form a chain structure. The infinitechains of [Na（Mo8O26）]^3- blocks are surrounded by protonized 4,4＇-bpy cations, 4,4＇-bpy and lattice crystalline water molecules. The 2D-IR correlation spectroscopy study indicates that the stretching vibrations of Mo=O occur more preferentially due to the thermal effect. The TGA analysis shows that compound 1 has high thermal stability.

Study on the Hydrogen Bond Interaction Between Soy Protein Isolate and Glycerol Using Two-Dimensional Correlation Fourier-Transform Infrared Spectroscopy

A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.

Application of Grey-correlated Spectral Region Selection in Analysis of Near-infrared Spectra

The optimal selection method of spectral region based on the grey correlation analysis was applied in the analysis of near-infrared（NIR） spectra. In order to compute ＂characteristic＂ spectral region, 160 samples of tobacco were surveyed by NIR. Next, the whole spectral region was randomly divided into six regions, and the values of association coefficients and correlation orders of different regions were computed for total sugar, reducing sugar and nicotine. Moreover, two regions that owned the largest value of association coefficient were regarded as ＂characteristic＂ spectral region of a model. Finally, the quantitative analysis models of different components were established via the partial least squares method, and the common selection methods of spectral region were compared. The simulation results indicate that the models to choose the spectral region based on grey correlation analysis are more effective than the common selection methods of spectral region, the optimized time of algorithm is shorter, the prediction precision of the models is higher and generalization ability for quantitative analysis results is stronger. This research can provide the support for the quantitative analysis models of NIR spectra and new idea for commercial analysis software of NIR. So, it has a high application value in the analysis of NIR spectra.

Generalized two-dimensional correlation near-infrared spectroscopy and principal component analysis of the structures of methanol and ethanol

Liquid state methanol and ethanol under different temperatures have been investigated by FT-NIR(Fourier transform nearinfrared) spectroscopy,generalized two-dimensional(2D) correlation spectroscopy,and PCA(principal component analysis) . First,the FT-NIR spectra were measured over a temperature range of 30-64(or 30-71) °C,and then the 2D correlation spectra were computed.Combining near-infrared spectroscopy,generalized 2D correlation spectroscopy,and references,we analyzed the molecular structures(especially the hydrogen bond) of methanol and ethanol,and performed the NIR band assignments. The PCA method was employed to verify the results of the 2D analysis.This study will be helpful to the understanding of these reagents.

Depth profiling of SBS/PET layered materials using step-scan phase modulation Fourier transform infrared photoacoustic spectroscopy and two-dimensional correlation analysis

This paper demonstrates the application of step-scan phase modulation Fourier transform infrared photoacoustic spectroscopy(FTIR-PAS) in non-destructively depth profiling of styrene-butadiene-styrene block copolymer/polyethylene terephthalate(SBS/PET) layered materials.The surface thicknesses of three layered samples were determined to be 1.2,4.3 and 9.4μm by using phase difference analysis,overcoming the spatial detection limits of FTIR.Combined with generalized two-dimensional(G2D) FTIR correlation analysis,the spatial origins of peaks in the SBS/PET spectrum are identified with those having overlapping peaks between different layers are resolved.

Solvent effects on infrared spectra of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine： Part 1. Single solvent systems

Infrared spectroscopy studies of 2 methyl 4,5 dimethoxy 3 oxo 2H pyridizine (MDOP) in 12 pure organic solvents were undertaken to investigate the solvent solute interactions. The frequencies of the carbonyl (C=O) of MDOP were correlated with solvent properties such as solvent acceptor number (AN) and the linear solvation energy relationships (LSER). These frequencies showed a good correlation with the solvent acceptor number (AN) and the LSER.

USING TWO-DIMENSIONAL TIME RESOLVED LIGHT SCATTERING TO STUDY THE CURE REACTION INDUCED PHASE SEPARATION PROCESS OF EPOXY-AMINE-POLYETHERSULFONE BLEND WITH SECONDARY PHASE SEPARATION

The generalized two-dimensional correlation analysis based on time-resolved light scattering patterns （2D TRLS） has been employed to study the phase separation process of an epoxy-amine-polyethersulfone blend in which the secondary phase separation takes place. The results of the 2D TRLS provided more detailed information that was not readily observed in the 1D TRLS patterns. （i） During the first process of phase separation, the sequential order of coarsening in size of the domains among the larger and smaller ones has been reversed between the diffusion regime and the hydrodynamic regime. （ii） The change of the larger domains in size, due to the hydrodynamic flow in the late stage of the first phase separation process, keeps on taking place earlier than that of the new domains appeared in the secondary phase separation process. （iii） During the secondary phase separation process the size growth of the smaller domains takes place earlier than that of the larger ones, probably due to the assumption that the coarsening mode could decrease the interface tension more quickly.

Two-dimensional correlation analysis of continuous online in situ ATR-FTIR on the adsorption of butyl xanthate at the surface of α-PbO

The adsorption behavior of butyl xanthate on the surface of lead oxide was investigated using continuous online in situ attenuated total reflectance Fourier transform infrared（ATR-FTIR） spectroscopy technique and two dimensional（2D） correlation analysis.The adsorbed layer studied was prepared by coating α-PbO particles onto the surfaces of the ZnSe crystal.The appearance of spectral peaks at 1203 cm^-1,1033 cm^-1 and their red shift indicated the formation and aggregation of xanthate at the surface of α-PbO.According to 1R intensity changes after rinsing with deionized water and a NaOH solution,the adsorption was proved to be a chemisorption type.The competition between xanthate and OH^- for the surfaces leads to desorption of xanthate at higher pH.The technique of 2D correlation ATR-FTIR spectroscopy was used to evaluate the changing order of spectral intensities in the adsorption process,and the results indicated that xanthate micelles were formed at the surfaces.The adsorption kinetics of butyl xanthate was found to be a pseudo-second-order reaction model and the adsorption capacity of butyl xanthate at α-PbO was as high as 281 mg g^-1 after 150 min.

Analysis and discrimination of ten different sponges by multi-step infrared spectroscopy

In this study,a convenient method using multi-step infrared spectroscopy,including Fourier transform infrared spectroscopy（FT-IR）,second derivative infrared spectroscopy（SD-IR） and two-dimensional correlation infrared spectroscopy（2DCOS-IR）,was employed to analyze and discriminate ten marine sponges from two classes collected from the Xisha Islands in the South China Sea.Each sponge had an exclusive macroscopic fingerprint.From the IR spectra,it was noted that the main ingredient of calcareous sponges was calcium carbonate,but that of demosponges was proteins.For sponges from the same genus or having highly similar chemical profile（IR spectral profile）,SD-IR and 2DCOS-IR were applied to successfully reveal the tiny differences.It was demonstrated that the multi-step infrared spectroscopy was a feasible and objective approach for marine sponge identification.

基于二维相关红外光谱对pH值影响大豆分离蛋白二级结构含量的快速分析

为满足不同种类食品对大豆分离蛋白(soybean protein isolate,SPI)不同功能性的需求,本研究利用红外光谱快速采集70组不同pH值处理后SPI的数据,探讨pH值变化对SPI结构含量的影响。使用均值中心化、多元散射校正、标准正态变量变换和归一化算法对红外光谱数据进行预处理,基于二维相关红外光谱提取特征波段,再利用偏最小二乘(partial least square,PLS)法和算术优化算法-随机森林(arithmetic optimization algorithm-random forests,AOA-RF)建立不同pH值条件下SPI结构及含量的预测模型。结果表明,经均值中心化和多元散射校正结合处理后,α-螺旋、β-折叠、β-转角和无规卷曲模型的相对标准偏差分别为1.29%、1.60%、1.37%、7.28%,两者结合对光谱数据的预处理效果最佳。预测α-螺旋和β-折叠含量最优模型为AOA-RF(特征波段),校正集决定系数为0.9350和0.9266,预测集决定系数为0.8568和0.8701;预测β-转角和无规卷曲含量最优模型为PLS(特征波段),校正集决定系数为0.9154和0.8817,预测集决定系数为0.8913和0.7843。本研究结果可为工业生产过程中产品质量快速检测和工艺条件控制提供理论支撑。

沥青老化前后宏-微观性能相关性

为探索沥青老化过程中微观结构变化对其宏观力学性能的内在影响机制,结合动态剪切流变仪测定的流变学参数与红外光谱仪及荧光显微镜获取的化学官能团和微观结构数据,揭示了基质沥青与SBS改性沥青在不同老化阶段的宏-微观性能关联。研究发现,SBS改性沥青的微观空间网络结构赋予其卓越的黏弹特性。识别了SBS改性剂特有的红外光谱特征峰,为快速识别和评估SBS改性沥青提供了一种方法。通过灰色关联度分析,发现官能团指数与复数剪切模量的关联度排序为:亚砜基官能团指数>芳香环官能团指数>羰基官能团指数,与沥青表面能的关联度顺序为:芳香环官能团指数>羰基官能团指数>亚砜基官能团指数。研究进一步证实,沥青老化过程中官能团的氧化和微观形貌的重构是影响其复数剪切模量变化的关键因素,为沥青材料的老化行为提供了新的理论解释。

红外特征提取与关联分析的设备故障预警方法

水电站电气设备的安全稳定运行至关重要。为了实现设备故障的自动预警,通过红外特征提取并进行灰色关联分析,提出建立主成分分析(PCA)和基于密度的聚类算法(DBSCAN)的设备故障预警模型。首先,通过数据预处理补全缺失数据,剔除异常数据后进行主成分分析降维并提取新的主成分特征。其次,将新的主成分采用DBSCAN算法构建特征样本集,建立灰色关联模型,计算灰色关联系数,然后,通过灰色关联系数的变化程度突变点进行故障预警。实验结果表明,所提方法能有效提取红外特征,并在设备异常状态下实现设备故障预警,故障预警准确率达到97.88%。

基于主成分和CSQS评价全国不同区域全株玉米青贮质量

本试验旨在利用主成分和全株玉米青贮质量分级评分(CSQS)方法,探究全国不同区域规模化牧场窖贮的全株玉米(Zea mays)青贮品质,为评价和制作全株玉米青贮饲料提供理论依据。结果表明:1)不同地区的全株玉米青贮饲料营养成分和发酵质量差异显著(P<0.05)。2)全株玉米青贮质量分级评分(CSQS)通过粗蛋白质含量、淀粉含量、粗脂肪含量、30 h中性洗涤纤维消化率4个营养指标,以及氨态氮含量、乳酸含量2个发酵指标将17个不同省份青贮饲料分为5个等级。不同地区全株玉米青贮品质由高到低依次是黄淮海地区(CSQS=64.42)(山东、河北、河南、安徽);东北地区(CSQS=59.72)(黑龙江、吉林、辽宁及内蒙古);西北地区(CSQS=58.99)(陕西、山西、青海、甘肃、新疆及宁夏);西南地区(CSQS=52.87)(云南和贵州);华南地区(CSQS=48.41)(广西)。其中黄淮海地区制作青贮饲料质量品质较好。3)根据主成分分析前3个主成分累积贡献率83.201%,这3个主成分分别反映了全株玉米青贮的中性洗涤纤维消化率、粗纤维和有机酸方面的综合品质。

二维相关红外光谱和高光谱成像技术检测黄精干燥过程中多糖的变化

[目的]研究黄精“一蒸一制”炮制工艺中干燥过程多糖的变化。[方法]采用常压隔水蒸对黄精切片进行蒸制,然后在60℃条件下进行热泵干燥,利用近红外光谱(NIR)、高光谱成像(HSI)和中远红外光谱技术对黄精干燥过程中的特征光谱进行解析,并结合二维相关红外光谱(2D-IR)分析方法研究黄精干燥过程中的多糖变化。[结果]蒸汽加热11 h后黄精多糖含量为3.39%,干燥11 h后多糖含量为6.67%,整体来看,黄精在干燥过程中多糖含量呈逐渐增多的趋势。通过二维相关分析可知,多糖的特征官能团在不断发生变化,在1 016 cm^(-1)处,其官能团变化顺序均为—CH2的C—H伸展→O—H基团在水中拉伸和变形→N—H基团的伸缩振动→O—H拉伸和C—O拉伸组合→C—H拉伸和C—C拉伸组合→吡喃糖苷;HSI技术结合化学计量学,利用PLSR建立多糖的光谱预测模型,模型的R2p为0.903。[结论]红外光谱、HSI技术结合2D-IR技术能很好地监测黄精在干燥过程中的多糖变化规律。

基于近红外光谱-光纤液滴分析法检测蓝莓综合品质

基于近红外光谱融合液滴分析技术进行蓝莓的二维相关分析,以实现蓝莓综合贮藏品质的检测。本研究采集8个贮藏时间‘绿宝石’蓝莓的近红外光谱图和液滴指纹图,综合分析硬度、花青素、VC、固酸比等15个理化指标,发现各指标之间有着密切的相关性,因此对15个理化指标进行隶属函数联合主成分分析计算蓝莓的综合得分,以此划分综合贮藏品质的等级。对光谱数据进行Savitzky-Golay(SG)卷积平滑、标准正态变换、多元散射矫正和迭代自适应加权惩罚最小二乘预处理,经对比分析,SG卷积平滑预处理后所建立的模型预测精度最高,预测结果为82.67%。对液滴数据取平均进行数据降维后进行移动平均平滑、SG卷积平滑、高斯滤波和中值滤波预处理,经过对比分析,经SG卷积平滑预处理后所建立的模型预测精度最高,预测结果为86.67%。以蓝莓的综合得分作为外扰,对光谱数据和液滴数据分别进行二维相关分析,分别优选出879、1019、1220、1636 nm波长和789、1653、2386、2703 ms自相关峰所对应的位置作为特征变量,以光谱和液滴特征数据融合后作为输入建立支持向量机(support vector machine,SVM)和随机森林模型,模型预测准确率分别为100.00%和98.33%,均高于以单个特征作为输入的预测准确率,且SVM模型预测效果更优,之后用‘蓝宝石’‘莱克西’和‘蓝丰’等9个蓝莓品种进行验证,采用相同的方法进行一系列数据处理建立SVM模型,结果表明模型对于不同品种蓝莓均表现出良好的预测效果。综上,利用可见-近红外光谱融合液滴分析技术可以实现蓝莓综合贮藏品质的预测,为蓝莓的品质检测提供新的方法。

广义二维相关光谱学进展

介绍了一种重要的广义二维相关光谱方法,对其基本原理、获取谱图的方法、数学计算过程、谱图的性质及其解释规则等作了详细的介绍,并介绍了其在化学、物理、生物、医药等领域中的应用。

多元散射校正对近红外光谱分析定标模型的影响

采用近红外漫反射光谱分析技术,用傅里叶变换型光谱仪对50个烟叶样品采集吸收光谱,采用常用的多元散射校正(MSC)对光谱预处理,通过主成分分析、相关谱等方法比较分析了预处理对光谱分析的影响,用偏最小二乘(PLS)回归法建立近红外光谱与总糖含量的定标模型,用 Leave One Out的交叉检验(Cross Validation)检验定标模型,结果 PLS 因子数由 MSC校正前的 5 降为校正后的 3,RM SECV值仅由0.884 1%降为0.85%。实验证明:对光谱进行MSC预处理能有效减少模型的最佳因子数,简化数学模型,使模型更稳定,更便于传递,但并不能显著减小最优定标模型的预测标准差,即不能显著提高模型的预测能力。

蒙药草乌花及其提取物化学成分的红外光谱法整体结构解析

采用傅立叶变换红外光谱法并借助于二阶导数谱以及二维相关红外光谱(2D-FTIR)研究了蒙药草乌花原药材及不同溶剂提取物(依次采用乙醚,乙醇和水提取)所含化学成分的红外谱图整体变化规律。结果显示:在草乌花原药材中具有明显的多糖类化合物的红外特征吸收峰,证明该药材中含有大量多糖类成分。草乌花药材乙醚和醇提物的红外光谱较相似,有较强的羰基吸收峰(1734和1713 cm-1)和饱和烷基的特征吸收峰(2960,2920和2851 cm-1),说明二者含有大量的脂肪酸(酯)等低极性成分。在分辨率较高的二阶导数谱中,两者的差异更为明显,水提物中含有脂肪酸(酯)类化合物,红外光谱法可以提供大量的结构信息。这种将药材整体谱图与不同溶剂提取物谱图及不同提取工艺之间的谱图相对照分析的研究方法,可观测药材化学成分的整体变化规律,有助于药材的整体质量控制、有效部位的定性宏观追踪及不同提取工艺的鉴别。

土壤温度检测及其与含水率关系研究

为实现在小面积范围内对土壤水分的遥感监测,采用IRI1011红外热像仪测量土壤温度,并试图通过土壤温度来预测土壤含水率。分别测量不同深度0~5 cm、0~10 cm、0~15 cm、0~20 cm的土壤温度和土壤含水率,分析土壤含水率和温度之间的关系。结果表明,深度为0~20 cm的土壤平均含水率与温度之间的线性相关系数R2为0.658。通过一天中不同时间段即上午、中午、下午的测量结果可知,在外界环境条件变化不大的情况下,中午时段0~5 cm土壤平均含水率和温度之间线性相关系数R2为0.794。

红外光谱结合二维相关分析研究堆肥过程腐殖酸演化规律

堆肥材料中腐殖酸的组成和结构直接影响堆肥产品品质和腐熟度。为研究堆肥腐殖酸的组成和形成过程,进行了生活垃圾堆肥并提取了不同堆肥阶段样品中的胡敏酸和富里酸,采用红外光谱和二维相关分析,探讨了堆肥过程胡敏酸、富里酸的组成、结构及随时间演化规律。红外光谱结果显示,堆肥胡敏酸组成复杂,在2 917~2 924,2 844~2 852,2 549,1 662,1 566,1 454,1 398,1 351,990~1 063,839,711cm-1均出现了吸收峰;相对于胡敏酸,堆肥富里酸结构简单,仅在1 725,1 637,990cm-1出现了吸收峰。上述吸收峰的出现表明堆肥胡敏酸和富里酸均含有木质素来源的苯环和糖类结构,但胡敏酸还含有丰富的脂族和蛋白类结构,这些在富里酸中含量较低;堆肥过程糖类、脂类、蛋白类及木质素结构均发生了降解,但是在胡敏酸和富里酸中它们的降解优先顺序不同。二维相关光谱分析结果表明,胡敏酸中降解先后顺序为脂肪类—蛋白类—多糖类和木质素,而富里酸中为蛋白质—多糖和脂肪类,降解过程均生成了羧酸、酮类和酯类结构,其中羧酸类物质一部分在堆肥中形成了碳酸盐。研究结果表明,红外光谱结合二维相关分析不仅可以获得堆肥腐殖酸官能团组成,还可以揭示堆肥过程这些官能团降解顺序,确定堆肥腐殖酸合成机制和动力学过程。