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.

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.

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.

Monitoring real time polymorphic transformation of sulfanilamide by diffuse reflectance visible spectroscopy

This study investigated the development of a novel approach to surface characterization of drug poly- morphism and the extension of the capabilities of this method to perform ＇real time＇ in situ measure- ments. This was achieved using diffuse reflectance visible （DRV） spectroscopy and dye deposition, using the pH sensitive dye, thymol blue （TB）. Two polymorphs, SFN-β and SFN-γ, of the drug substance sulfanilamide （SFN） were examined. The interaction of adsorbed dye with polymorphs showed different behavior, and thus reported different DRV spectra. Consideration of the acid/base properties of the morphological forms of the drug molecule provided a rationalization of the mechanism of differential coloration by indicator dyes. The kinetics of the polymorphic transformation of SFN polymorphs was monitored using treatment with TB dye and DRV spectroscopy. The thermally-induced transformation fitted a first-order solid-state kinetic model （R2=0.992）, giving a rate constant of 2.43 × 10^- 2 s 1.

氢氧化钠分子结构原位漫反射一维及二维漫反射中红外光谱研究

通过原位一维漫反射中红外(MIR)光谱开展了氢氧化钠分子结构研究。实验发现,氢氧化钠分子结构主要红外吸收模式包括OH基团伸缩振动模式(νOH-NaOH-_(一维))和OH基团面内摇摆振动模式(ρOH-NaOH-_(一维))。进一步开展了氢氧化钠分子结构的原位二维漫反射MIR光谱研究。采用原位漫反射一维及二维漫反射MIR光谱开展氢氧化钠结构研究,对氯碱工业具有重要意义。

手持式马铃薯干物质含量无损检测装置设计与试验

面向马铃薯品质抽检的需求,研发了手持式马铃薯干物质无损检测装置。装置硬件部分包括光谱采集模块、电路控制模块、控制与显示模块、外壳模块,装置设计为枪形,尺寸为180 mm×85 mm×210 mm。利用装置采集可见近红外漫反射光谱,比较Savitzky-Golay卷积平滑(SM)、一阶导数(first-order derivative,FD)、多元散射校正(multiple scattering correction,MSC)和标准正态变量变换(standard normal variate transformation,SNV)的预处理方式,SM结果较优。采用竞争性自适应重加权采样(competitive adapative reweighted sampling,CARS)筛选27个特征波长,建立马铃薯干物质含量的支持向量回归(support vector regression,SVR)预测模型,结果显示,验证集决定系数和均方根误差分别为0.802和0.98%。基于QT开发工具编写装置软件,包括黑白校正与测量模块、电量显示模块、光谱数据显示模块、保存数据模块、光谱数据刷新模块、检测结果显示模块。开展装置验证,预测均方根误差为1.01%,单次测量平均耗时为0.62 s。结果表明,手持式马铃薯干物质无损检测装置可快速、准确检测干物质含量,具有在马铃薯生产源头与加工现场应用的潜力。

原位漫反射中红外光谱在氢氧化钠杂质分析的应用

对原位漫反射中红外光谱开展了氢氧化钠杂质研究。实验发现:氢氧化钠杂质主要包括:少量碳酸钠和水。碳酸钠分子主要的红外吸收模式包括:C=O基团伸缩振动模式(νC=O-Na_(2)CO_(3))和CO_(3)基团面内弯曲振动模式(βCO_(3)-Na_(2)CO_(3))的合频峰(νC=O-Na_(2)CO_(3)+βCO_(3)-Na_(2)CO_(3));C=O基团伸缩振动模式(νC=O-Na_(2)CO_(3));CO_(3)基团不对称伸缩振动模式(νasCO_(3)-Na_(2)CO_(3));CO_(3)基团对称伸缩振动模式(νsCO_(3)-Na_(2)CO_(3));CO_(3)基团面外弯曲振动模式(rCO_(3)-Na_(2)CO_(3))及CO_(3)基团面内弯曲振动模式(βCO_(3)-Na_(2)CO_(3));水分子主要的红外吸收模式包括:OH基团伸缩振动模式(νOH-H_(2)O)。原位漫反射中红外光谱在氢氧化钠杂质分析领域,具有重要的应用研究价值。

聚光太阳能驱动二氧化碳甲烷化实验研究

针对聚光光热驱动CO_(2)甲烷化反应过程中聚光的作用机制尚不清晰的问题,以具有优异反应活性及光热转换特性的Ni/Al_(2)O_(3)催化剂为研究对象,开展了聚光光热驱动和热驱动下的CO_(2)甲烷化实验及机理研究。通过表观活化能测试、温度梯度实验及时间分辨的原位漫反射红外光谱实验,探究了聚光在反应过程中的作用机制,揭示了光热驱动CO_(2)甲烷化的反应机理。结果表明,与纯热驱动过程相比,光热驱动在相同温度下表现出更佳的催化性能。光热驱动下w(Ni)为15%的Ni/Al_(2)O_(3)催化剂在350℃下可达到86.8%的CO_(2)转化率,达到峰值转化率所需的温度比纯热驱动过程降低了25℃。此外,光热较热驱动过程的表观活化能降低了25%,且光致温度梯度进一步促进了CO_(2)的转化。时间分辨的原位漫反射红外光谱实验结果表明,聚光改善了CO_(2)在催化剂表面的吸附,促进了关键中间体的转变,增强了CO*生成CH4的反应路径,从微观动力学上促进了CO_(2)的转化。该研究为认识聚光太阳能驱动CO_(2)甲烷化过程中聚光的作用机制提供了新的思路。

土壤有机质可见-近红外反射光谱特性研究

为优化土壤有机质含量预测模型运算速度,以50份土壤有机质为例,利用Pearson相关系数分析法对土壤有机质的特征波段进行提炼筛选。结果表明,土壤样品的反射光谱与土壤有机质含量在555~662 nm波段范围内呈较强负相关,显著特征波段为601 nm;经过不同预处理后的土壤反射光谱与土壤有机质含量呈较强的相关性,显著特征波段增加,主要体现在601、1221、1410、1665、1880、2110、2200 nm波段附近。对不同土壤含水率的反射光谱与土壤有机质含量之间的Pearson相关曲线进行分析发现,显著特征波段主要体现在601、1450、1930、2200 nm波段附近,随着土壤含水率的增加,土壤有机质的特征波段601 nm的相关性逐渐减弱,土壤水分的特征波段1450、1930、2200 nm的相关性逐渐加强;土壤含水率超过10%,土壤反射光谱与土壤有机质含量呈正相关。研究获取的土壤有机质特征波段和土壤水分影响波段,为土壤有机质快速检测模型的建立提供理论支撑。

丙酮盐酸混合液提取土壤腐殖质组分的光谱学特征

采用丙酮盐酸混合液提取土壤胡敏酸(HA)和胡敏素(HU)组分,利用元素分析、紫外-可见漫反射光谱和红外光谱进行结构表征。元素分析表明,HA中C、H、N和S含量均高于HU,O含量低于HU。原子比分析表明HA的缩合度相对较高,分子结构相对复杂,HU的缩合度相对较低,分子结构相对简单。紫外-可见漫反射光谱分析表明,由于腐殖质(HS)的组成复杂,多种官能团互相干扰,HA和HU紫外-可见漫反射光谱无明显特征峰,吸光度值随着波长的增加呈下降趋势,且HA包含的吸光有机成分较多,化学组成较复杂。HA和HU紫外特征参数SUV254和E4/E6比较分析表明,与HU相比,HA芳香性较大,腐殖化程度较高。红外光谱分析表明,HA和HU具有相似的红外光谱,各研究对象特征吸收峰的吸收强度不同,其中开垦黑土20~40 cm和未开垦灰土18~37 cm土层HA的振动幅度较大,说明其包含的酚类化合物、含羟基化合物、脂肪族化合物和羧酸,以及含羰基的醛、酮、醚等化合物的含量较多。开垦黑土10~20 cm土层和未开垦灰土18~37 cm土层HU在各特征吸收峰振动幅度较大,说明其包含的酚类化合物、羧酸、脂肪烃和糖类化合物含量较多。红外光谱各吸收峰强度比较分析表明,开垦后黑土HA和HU酚类化合物、羟基官能团和脂肪族化合物等含量增加,而开垦后灰土HA和HU酚类化合物、羧酸和脂肪族化合物含量下降,表明开垦对黑土土壤有机质影响相对较小,并且在一定程度上增加了土壤有机质含量,而促进了灰土土壤有机质的分解。综上所述,丙酮盐酸混合液提取法为HS生物化学和生理活性的研究提供了新的技术手段,为合理利用土壤资源提供理论依据。

阿司匹林含量测定方法研究进展

阿司匹林为临床常用药品,因其确切的疗效和较小的药物不良反应而为大众所熟知,根据近年来阿司匹林含量测定方法研究成果,介绍滴定法、紫外-可见分光光度法、高效液相色谱法、近红外漫反射法等在测定阿司匹林含量方面的研究进展,为进一步开发阿司匹林新的检测方法提供参考依据。

Effects of Activation Atmospheres on Structure and Activity of Mo-based Catalyst for Synthesis of Higher Alcohols

Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.

Improving visible-light-driven photocatalytic NO oxidation over BiOBr nanoplates through tunable oxygen vacancies

In this work,a series of BiOBr nanoplates with oxygen vacancies(OVs)were synthesized by a solvothermal method using a water/ethylene glycol solution.The number of OVs and facets of BiOBr were tuned by changing the water/ethylene glycol ratio.Although the role of OVs in photocatalysis has been investigated,the underlying mechanisms of charge transfer and reactant activation remain unknown.To unravel the effect of OVs on the reactant activation and photocatalytic NO oxidation process,in situ diffuse reflectance infrared Fourier transform spectroscopy,so‐called DRIFTS,and theoretical calculations were performed and their results combined.The photocatalytic efficiency of the as‐prepared BiOBr was significantly increased by increasing the amount of OVs.The oxygen vacancies had several effects on the photocatalysts,including the introduction of intermediate energy levels that enhanced light absorption,promoted electron transfer,acted as active sites for catalytic reaction and the activation of oxygen molecules,and facilitated the conversion of the intermediate products to the final product,thus increasing the overall visible light photocatalysis efficiency.The present work provides new insights into the understanding of the role of OVs in photocatalysts and the mechanism of photocatalytic NO oxidation.

Visible light-enhanced photothermal CO2 hydrogenation over Pt/Al2O3 catalyst

Light illumination has been widely used to promote activity and selectivity of traditional thermal catalysts. Nevertheless, the role of light irradiation during catalytic reactions is not well understood. In this work, Pt/Al2 O3 prepared by wet impregnation was used for photothermal CO2 hydrogenation, and it showed a photothermal effect. Hence, operando diffuse reflectance infrared Fourier-transform spectroscopy and density functional theory calculations were conducted on Pt/Al2 O3 to gain insights into the reaction mechanism. The results indicated that CO desorption from Pt sites including step sites(Ptstep) or/and terrace site(Ptterrace) is an important step during CO2 hydrogenation to free the active Pt sites. Notably, visible light illumination and temperature affected the CO desorption in different ways. The calculated adsorption energy of CO on Ptstep and Ptterrace sites was-1.24 and-1.43 e V, respectively. Hence, CO is more strongly bound to the Ptstep sites. During heating in the dark, CO preferentially desorbs from the Ptterrace site. However, the additional light irradiation facilitates transfer of CO from the Ptstep to Ptterrace sites and its subsequent desorption from the Ptterrace sites, thus promoting the CO2 hydrogenation.

Facile synthesis of Bi_(12)O_(17)Br_2 and Bi_4O_5Br_2 nanosheets:In situ DRIFTS investigation of photocatalytic NO oxidation conversion pathway

Bi12O17Br2and Bi4O5Br2visible‐light driven photocatalysts,were respectively fabricated by hydrothermal and room‐temperature deposition methods with the use of BiBr3and NaOH as precursors.Both Bi12O17Br2and Bi4O5Br2were composed of irregular nanosheets.The Bi4O5Br2nanosheets exhibited high and stable visible‐light photocatalytic efficiency for ppb‐level NO removal.The performance of Bi4O5Br2was markedly higher than that of the Bi12O17Br2nanosheets.The hydroxyl radical(?OH)was determined to be the main reactive oxygen species for the photo‐degradation processes of both Bi12O17Br2and Bi4O5Br2.However,in situ diffuse reflectance infrared Fourier transform spectroscopy analysis revealed that Bi12O17Br2and Bi4O5Br2featured different conversion pathways for visible light driven photocatalytic NO oxidation.The excellent photocatalytic activity of Bi4O5Br2resulted from a high surface area and large pore volumes,which facilitated the transport of reactants and intermediate products,and provided more active sites for photochemical reaction.Furthermore,the Bi4O5Br2nanosheets produced more?OH and presented stronger valence band holeoxidation.In addition,the oxygen atoms of NO could insert into oxygen‐vacancies of Bi4O5Br2,whichprovided more active sites for the reaction.This work gives insight into the photocatalytic pollutant‐degradation mechanism of bismuth oxyhalide.

Adsorption of NO and NH_3 over CuO/γ-Al_2O_3 catalyst

The selective catalytic reduction reaction belongs to the gas-solid multiphase reaction, and the adsorption of NH3 and NO on CuO/γ-Al2O3 catalysts plays an important role in the reaction. Performance of the CuO/γ-Al2O3 catalysts was explored in a fixed bed adsorption system. The catalysts maintain nearly 100% NO conversion efficiency at 350℃. Comprehensive tests were carried out to study the adsorption behavior of NH3 and NO over the catalysts. The desorption experiments prove that NH3 and NO are adsorbed on CuO/γ-Al2O3 catalysts. The adsorption behaviors of NH3 and NO were also studied with the in-situ diffusion reflectance infrared Fourier transform spectroscopy methods. The results show that NH3 could be strongly adsorbed on the catalysts, resulting in coordinated NH3 and NH4＋. NO adsorption leads to the formation of bridging bidentate nitrate, chelating bidentate nitrate, and chelating nitro. The interaction of NH3 and NO molecules with the Cu2＋ present on the CAl2O3 （100） surface was investigated by using a periodic density functional theory. The results show that the adsorption of all the molecules on the Cu2＋ site is energetically favorable, whereas NO bound is stronger than that of NH3 with the adsorption site, and key information about the structural and energetic properties was also addressed.

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.

Surface Modification of (001) Facets Dominated TiO2 with Ozone for Adsorption and Photocatalytic Degradation of Gaseous Toluene

This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated（001） facets for toluene degradation.The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modification, toluene adsorption and degradation mechanism were established by a combination of various characterization methods, in situ diffuse reflectance infrared fourier transform spectroscopy, and density functional theory calculation.The surface modification with ozone can significantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5 c-Ti sites on（001）facets act as the adsorption sites for ozone. The formed Ti–O bonds reacted with H2O to generate a large amount of isolated Ti5 c-OH which act as the adsorption sites for toluene,and thus significantly increase the adsorption capacity for toluene. The outstanding photocatalytic performance of ozone-modified TiO2 is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH·radicals under irradiation. Furthermore, the O2 generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation.