The Study of Using Near-infrared Diffuse Reflectance Spectroscopy Rapid Identify Wheat Drought Resistance-Ⅱ

[Objective] The aim was to build an evaluation method rapidly identifying wheat drought tolerance with near infrared diffuse reflectance spectroscopy. [Method] In the research, 36 wheat varieties in 2007-2009 were chosen and drought-tolerance degrees of wheat were graded and identified according to Winter-wheat Drought Tol- erance Evaluation Technical Standards （GB/T 21127-2007）, and harvest wheat grains underwent spectrum collection, with a full-spectrum analyzer, to establish a database. [Result] Based on qualitative analysis and full-spectrum correlation research, the coef- ficient of determination （RSQ） and cross-validation coefficient of determination （1-VR） were concluded at 0.697 5 and 0.600 2, showing near-infrared diffuse reflectance spectroscopy is of significant differences among wheat varieties and of significant or extremely significant correlation with drought-tolerance indices. [Conclusion] The re- search indicates that to evaluate drought-tolerance of wheat with near-infrared diffuse reflectance spectroscopy is a rapid and feasible way, which is simple, convenient without damages on grains, and of practical values for construction wheat drought-tol- erance evaluation index system and identification of breeding materials.

Supercritical water syntheses of transition metal-doped CeO_2 nano-catalysts for selective catalytic reduction of NO by CO:An in situ diffuse reflectance Fourier transform infrared spectroscopy study

In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.

Rapid, Non-Destructive, Textile Classification Using SIMCA on Diffuse Near-Infrared Reflectance Spectra

Soft independent modeling of class analogy (SIMCA) was successful in classifying a large library of 758 commercially available, non-blended samples of acetate, cotton, polyester, rayon, silk and wool 89% - 98% of the time at the 95% confidence level (p = 0.05 significance level). In the present study, cotton and silk had a 62% and 24% chance, respectively, of being classified with their own group and also with rayon. SIMCA correctly identified a counterfeit “silk” sample as polyester. When coupled with diffuse NIR reflectance spectroscopy and a large sample library, SIMCA shows considerable promise as a quick, non-destructive, multivariate method for fiber identification. A major advantage is simplicity. No sample pretreatment of any kind was required, and no adjust-ments were made for fiber origin, manufacturing process residues, topical finishes, weave pattern, or dye content. Increasing the sample library should make the models more robust and improve identification rates over those reported in this paper.

Determination of Active Components in a Natural Herb with Near Infrared Spectroscopy Based on Artificial Neural Networks

The non-linear relationships between the contents of ginsenoside Rg 1, Rb 1, Rd and Panax notoginseng saponins(PNS) in Panax notoginseng root herb and the near infrared(NIR) diffuse reflectance spectra of the herb were established by means of artificial neural networks(ANNs). Four three-layered perception feed-forward networks were trained with an error back-propagation algorithm. The significant principal components of the NIR spectral data matrix were utilized as the input of the networks. The networks architecture and parameters were selected so as to offer less prediction errors. Relative prediction errors for Rg 1, Rb 1, Rd and PNS obtained with the optimum ANN models were 8.99%, 6.54%, 8.29%, and 5.17%, respectively, which were superior to those obtained with PLSR methods. It is verified that ANN is a suitable approach to model this complex non-linearity. The developed method is fast, non-destructive and accurate and it provides a new efficient approach for determining the active components in the complex system of natural herbs.

Titanium dioxide as an adsorbent to enhance the detection ability of near-infrared diffuse reflectance spectroscopy

A method for quantitative determination of fish sperm deoxyribonucleic acid(fsDNA)was developed by using titanium dioxide(TiO2)as an adsorbent and near-infrared diffuse reflectance spectroscopy(NIRDRS).The selective enrichment of fsDNA was proved by comparing the adsorption efficiency of bovine serum albumin,tyrosine and tryptophan,and the low adsorption background of TiO2 was illustrated by comparing the spectra of four commonly-used inorganic adsorbents(alkaline aluminium oxide,neutral aluminium oxide,nano-hydroxyapatite and silica).The spectral feature of fsDNA can be clearly observed in the spectrum of the sample.Partial least squares(PLS)model was built for quantitative determination of fsDNA using 28 solutions,and 13 solutions with interferences were used for validation of the model.The results showed that the correlation coefficient(R)between the predicted and the reference concentration is 0.9727 and the recoveries of the validation samples are in the range of 98.2%-100.7%.

Determination of triglycerides in human serum by near-infrared diffuse reflectance spectroscopy using silver mirror as a substrate

Near infrared diffuse reflectance spectroscopy(NIRDRS) has gained wide attention due to its convenience for rapid quantitative analysis of complex samples. A method for rapid analysis of triglycerides in human serum using NIRDRS with silver mirror as the substrate is developed. Due to the even and high reflectance of the silver mirror, the spectral response is enhanced and the background interference is reduced.Furthermore, both linear and nonlinear modeling strategies were investigated adopting the partial least squares(PLS) and least squares support vector regression(LS-SVR), continuous wavelet transform(CWT)was used for spectral preprocessing, and variable selection was tried using Monte Carlo uninformative variable elimination(MC-UVE), randomization test(RT) and competitive adaptive reweighted sampling(CARS) for optimization the models. The results show that the determination coefficient(R) between the predicted and reference concentration is 0.9624 and the root mean squared error of prediction(RMSEP) is 0.21. The maximum deviation of the prediction results is as low as 0.473 mmol/L. The proposed method may provide an alternative method for routine analysis of serum triglycerides in clinical applications.

近红外漫反射光谱联合IL-17A在2型糖尿病患者牙周炎中的早期预测价值

目的 探究近红外漫反射光谱联合白介素17A(IL-17A)对2型糖尿病(T2DM)患者并发牙周炎的预测价值。方法 将2020年1月-2021年1月在我院就诊的T2DM患者分为牙周炎组与非牙周炎组。采用近红外漫反射光谱检测患者的牙龈血流动力学相关指标,分析患者血流动力学指标与IL-17A的相关性。结果 相比于非牙周炎组,牙周炎组患者的牙龈组织相对血流量(rGBF)降低,IL-17A、牙菌斑指数(PLI)、牙龈指数(GI)及龈沟出血指数(SBI)升高;rGBF与IL-17A呈负相关(r=-0.200),PLI与IL-17A呈正相关(r=0.201),均P <0.05。IL-17A联合红外漫反射光谱各项指标对T2DM患者牙周炎发生的预测效能明显优于各项指标单独预测的效能(P <0.05)。结论 红外漫反射光谱能够无创检测牙龈组织的相对血流量,其与IL-17A联合预测有望成为T2DM患者牙周炎早期预测和疗效、预后评价的方法之一。

Determination of optimal source-detector separation in measuring chromophores in layered tissue with diffuse reflectance

Based on analysis of the relation between mean penetration depth and source-detector separation in a threelayer model with the method of Monte-Carlo simulation, an optimal source-detector separation is derived from the mean penetration depth referring to monitoring the change of chromophores concentration of the sandwiched layer. In order to verify the separation, we perform Monte-Carlo simulations with varied absorption coefficient of the sandwiched layer. All these diffuse reflectances are used to construct a calibration model with the method of partial least square （PLS）. High correlation coefficients and low root mean square error of prediction （RMSEP） at the optimal separation have confirmed correctness of the selection. This technique is expected to show light on noninvasive diagnosis of near-infrared spectroscopy.

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 8.0 82 %～ 14 .5 4 8%。在 75 0 1.7～ 6 0 97.8cm- 1 与 5 4 5 3.7～ 4 2 4 6 .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 .4 75 ,预测误差均方根为 0 .6 0 8,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 。

基于可见-近红外漫反射光谱技术的葡萄贮藏期间可溶性固形物定量预测

利用可见-近红外漫反射光谱技术,建立不同品种葡萄贮藏期间可溶性固形物含量定量预测的通用模型。以10℃贮藏的玫瑰香葡萄、马奶葡萄、红提葡萄的混合光谱为定标材料,探讨不同化学计量学建模方法、不同光谱预处理方法、间隔点、平滑数以及不同特征波长区间选择对建模效果的影响及模型的品种适用性。结果显示,采用改进偏最小二乘法,16点平滑,间隔点数16点,结合二阶导数、去散射的处理方法,在波长范围408～1 092.8 nm内建立的模型效果最优,其交互验证误差和交互验证判定系数R2CV分别为0.308 7、0.980 2。由3种葡萄混合组成的预测集对模型进行评价,预测标准差0.354、预测判定系数Rp2为0.980 8、验证相对分析误差为6.22、预测残差平方和为7.993。模型对单一品种预测Rp2均达到0.94以上。因此,葡萄果实可溶性固形物含量的近红外预测模型具有可行性,可同时适用于多种葡萄品种。

基于CWT和GRNN的可见-近红外漫反射光谱检测樱桃糖度的研究

联合使用连续小波变换(continuous wavelet transform,CWT)和广义回归神经网络(generalized regression neural networks,GRNN)建立用于测定樱桃中糖含量的CWT-GRNN预测校正模型。利用CWT提取樱桃样本数据中反映含糖量的关键光谱特征,在CWT域中选择3个具有代表性的尺度,并在每个尺度下根据樱桃样本的可见-近红外光谱的特征将其划分为4个特征区间,从而构造12个特征输入到GRNN,GRNN的光滑因子取为0.0001。CWT-GRNN模型对20个预测样本集中的樱桃含糖量的预测相对误差在2%以内。结果表明,可见-近红外光谱技术可以快速、准确和无损地测定樱桃中的含糖量,本研究提出的方法可以用于果蔬产业的品质管理与控制。

原位漫反射红外光谱研究NO和NH_3在CuO/γ-Al_2O_3催化剂上的吸附行为

利用原位漫反射红外光谱法在线研究NH3和NO在CuO/γ-Al2O3催化剂表面吸附和氧化的反应过程。NH3不仅能被吸附在L酸位,也能被吸附在B酸位。NH3氧化脱氢形成NH2物种是反应的中间步骤。NO和NO2以多种形态吸附在催化剂表面。O2存在条件下有利于吸附的NO物种被氧化成高价的NO2。暂态实验中,吸附NH3饱和的催化剂载体通入NO和O2后,共价吸附的NH3首先消失,而NH+4没有参加反应。吸附NO饱和的催化剂载体通入NH3和O2后,吸附态NO特征峰基本没有变化。选择性催化还原反应发生在吸附态NH3和气态NO之间,吸附态的NO及其氧化生成的亚硝基和硝基物种不参与SCR反应。

钛硅分子筛TS-1上液相氨氧化制环己酮肟机理的原位红外研究

采用原位漫反射红外光谱法,对TS-1上环己酮和氨水、过氧化氢液相氧化反应体系进行了研究。结果表明,环己酮和氨水各自吸附,它们的混合物吸附均发生在表面—Si—OH,且二者相互作用生成亚胺中间物;过氧化氢与TS-1作用形成Ti的过氧化物—Ti—OOH,它与亚胺反应可形成肟。亚胺机理可以很好地解释一些高沸点有机物形成的原因。

TiO_2-SnO_2基钨催化剂的表面性质和NH_3吸附特性及脱硝机理

采用共沉淀法制备了TiO2-SnO2固溶体载体,浸渍WO3得到系列x%WO3/Ti O2-Sn O2脱硝催化剂,采用比表面积测定（BET）、X射线衍射（XRD）、高分辨率透射电子显微镜（HRTEM）、程序升温还原（H2-TPR）、原位漫反射傅里叶红外光谱（in situ DRIFTS）等表征研究脱硝催化剂的微观结构、表面性质和NH3吸附特性,并推测该催化剂表面的SCR脱硝反应机理.结果表明：负载WO3之后,随着负载量的增加,催化剂的比表面积有所减小;WO3以无定形态存在于催化剂表面;催化剂还原特性和表面Brnsted酸量显著增强;催化剂的脱硝效率增加,其中12%WO3/TiO2-SnO2催化剂在280~380℃的温度窗口具有90%的NOx转换效率.原位漫反射红外研究结果表明,对于x%WO3/TiO2-SnO2系列的催化剂来说,Brnsted酸中心是催化过程中的活性酸位,该催化剂脱硝反应遵循E-R反应机理.

Cu-SSZ-13柴油机SCR催化剂水热老化试验

为了完善柴油机铜基分子筛选择性催化还原(SCR)催化剂的失活机理,使用流动反应试验系统对一步合成法Cu-SSZ-13催化剂样品进行水热老化处理以及标准SCR、NH_3氧化、NH_3程序升温脱附(NH_3-TPD)等评价测试,并基于X射线衍射(XRD)、原位漫反射傅里叶变换红外光谱(DRIFTS)以及H_2程序升温还原(H_2-TPR)技术对样品进行微观表征分析.结果表明:850,℃水热老化会造成催化剂分子筛骨架结构垮塌,NH_3吸附活性位数目急剧下降,催化剂大幅度失活;而750,℃水热老化会造成催化剂布朗斯特(Br?nsted)酸性位减少,并发生孤立的Cu^(2+)位置迁移以及铜氧化物(CuO_x)生成等现象,使得催化剂SCR活性在一定程度上降低.

单质硫ν_(S-S)伸缩振动的漫反射红外光谱研究

采用傅里叶变换漫反射红外光谱法,在500~400cm^(-1)范围内研究了单质硫S-S键伸缩振动红外吸收模式(νS-S)的一维漫反射红外光谱、二阶导数漫反射红外光谱、四阶导数漫反射红外光谱和去卷积漫反射红外光谱,并针对单质硫νS-S,进一步开展了相关二维漫反射红外光谱研究。结果表明:单质硫νS-S的红外吸收频率主要包括464,466,468,474cm^(-1),而其红外吸收强度的变化顺序为464cm^(-1)>474cm^(-1)>468cm^(-1)>466cm^(-1)。

Cu-ZSM-5/堇青石整体式催化剂上NO的吸附态及分解反应机理

用傅里叶变换漫反射红外光谱法研究了原位合成的不同硅铝比的Cu ZSM 5 /堇青石整体式催化剂上一氧化氮的吸附态 ,以及温度和一氧化氮浓度对吸附态的影响 .结果表明 ,铜在整体式催化剂中主要以二价铜离子的形式存在 ,未发现一氧化氮在一价铜离子上的特征吸收峰 ;由二价铜的一氧化氮吸附物种衍生的Cu2 +(O) (NO)是与活性密切相关的物种 .

新型贵金属修饰的Ag/Al_2O-3催化剂选择性催化还原NO_x的催化性能及反应机理

在富氧条件下研究了几种贵金属修饰的Ag/Al2 O3 催化剂选择性催化还原 (SCR)NOx 的活性和反应机理 .催化活性实验结果表明 ,在模拟柴油机尾气的实验条件下 ,5 %Ag 0 0 1%Pd/Al2 O3 在 30 0～ 5 0 0℃范围内显示出很高的NOx 转化率 ,而Pt和Au的添加均使Ag/Al2 O3 的NOx 转化率明显降低 .原位漫反射傅里叶变换红外光谱结果显示 ,添加少量的Pd在反应过程中有利于丙烯部分氧化形成烯醇式 (C=CH-O-)活性中间物种 ,该物种对NO2 和NO-3 的反应活性很高 ,能够生成关键中间体异氰酸酯 (-NCO) ,从而加速NOx 催化还原反应 .

中红外漫反射光谱法测定CL-20晶型含量

采用中红外漫反射光谱技术结合化学计量学偏最小二乘法(PLS)建立了ε-CL-20产品中α-CL-20、γ-CL-20、ε-CL-20的定量校正模型,并对模型进行了交互验证和外部验证。结果表明:三种模型具有较高的准确度和精密度,交互验证决定系数(R2)分别为0.9973、0.9714、0.9848,交互验证标准偏差(RMSECV)分别为0.222%、0.650%、0.670%;外部验证预测标准偏差(RMSEP)分别为0.422%、0.813%、1.02%,配对t检验结果表明预测值与真值之间无显著性差异。基于上述模型的晶型定量分析方法适用于ε-CL-20的产品质量检验以及火炸药工艺过程、长贮过程中ε-CL-20的晶型稳定性研究。

Cu/HZSM-5催化剂低温SCR脱硝实验研究

采用浸渍法制备了不同Cu负载量的系列Cu/HZSM-5脱硝催化剂,通过XRD、H2-TPR、NH3-TPD、in situ DRIFTS等多种表征手段对催化剂进行了表征,并对其低温NH3-SCR脱硝性能进行测试。结果表明,Cu/HZSM-5催化剂在中低温均展现出较好脱硝效率,Cu负载量为20%的Cu/HZSM-5中低温脱硝效果最佳,288℃达到最大为96.89%,200～400℃温度范围脱硝效率均在80%以上。Cu物种高度分散在载体表面,未改变HZSM-5晶体结构。Cu/HZSM-520%催化剂具备丰富酸性位、优异的氧化还原性能,在NH3-SCR反应过程中只存在E-R机理,L酸性位在低温脱硝反应中发挥重要作用。