期刊文献+
共找到552篇文章
< 1 2 28 >
每页显示 20 50 100
Equidistant combination wavelength screening and step-by-step phase-out method for the near-infrared spectroscopic analysis of serum urea nitrogen 被引量:2
1
作者 Yihui Yang Fenfen Lei +3 位作者 Jing Zhang Lijun Yao Jiemei Chen Tao Pan 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2019年第6期85-96,共12页
We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve param... We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model. 展开更多
关键词 Serum urea nitrogen near infrared spectroscopic analysis Norris derivative filter equidistant combination wavelength screening wavelength step-by-step phase-out
原文传递
Visible and Near-Infrared Spectroscopic Discriminant Analysis Applied to Identification of Soy Sauce Adulteration 被引量:1
2
作者 Chunli Fu Jiemei Chen +1 位作者 Lifang Fang Tao Pan 《American Journal of Analytical Chemistry》 2022年第2期51-62,共12页
The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spe... The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spectroscopy combined with standard normal variate-partial least squares-discriminant analysis (SNV-PLS-DA) was used to establish the discriminant analysis models for adulterated and brewed soy sauces. Chubang soy sauce was selected as an identification brand (negative, 70). The adulteration samples (positive, 72) were prepared by mixing Chubang soy sauce and blended soy sauce with different adulteration rates. Among them, the “blended soy sauce” sample was concocted of salt water (NaCl), monosodium glutamate (C<sub>5</sub>H<sub>10</sub>NNaO<sub>5</sub>) and caramel color (C<sub>6</sub>H<sub>8</sub>O<sub>3</sub>). The rigorous calibration-prediction-validation sample design was adopted. For the case of 1 mm, five waveband models (visible, short-NIR, long-NIR, whole NIR and whole scanning regions) were established respectively;in the case of 10 mm, three waveband models (visible, short-NIR and visible-short-NIR regions) for unsaturated absorption were also established respectively. In independent validation, the models of all wavebands in the cases of 1 mm and 10 mm have achieved good discrimination effects. For the case of 1 mm, the visible model achieved the optimal validation effect, the validation recognition-accuracy rate (RAR<sub>V</sub>) was 99.6%;while in the case of 10 mm, both the visible and visible-short-NIR models achieved the optimal validation effect (RAR<sub>V</sub> = 100%). The detection method does not require reagents and is fast and simple, which is easy to promote the application. The results can provide valuable reference for designing small dedicated spectrometers with different measurement modals and different spectral regions. 展开更多
关键词 Visible and near-infrared spectroscopy Soy Sauce Adulteration Identification Partial Least Squares-Discriminant analysis Standard Normal Variate
在线阅读 下载PDF
Near-Infrared Spectroscopy Combined with Absorbance Upper Optimization Partial Least Squares Applied to Rapid Analysis of Polysaccharide for Proprietary Chinese Medicine Oral Solution 被引量:2
3
作者 Jiexiong Su Xinkai Gao +5 位作者 Lirong Tan Xianzhao Liu Yueqing Ye Yifang Chen Kaisheng Ma Tao Pan 《American Journal of Analytical Chemistry》 2016年第3期275-281,共7页
Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance up... Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L<sup>-</sup><sup>1</sup> and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods. 展开更多
关键词 near-infrared spectroscopic analysis Proprietary Chinese Medicine Oral Solution POLYSACCHARIDE Absorbance Upper Optimization Partial Least Squares
在线阅读 下载PDF
Near-Infrared Spectroscopy Combined with Partial Least Squares Discriminant Analysis Applied to Identification of Liquor Brands 被引量:6
4
作者 Bin Yang Lijun Yao Tao Pan 《Engineering(科研)》 2017年第2期181-189,共9页
The identification of liquor brands is very important for food safety. Most of the fake liquors are usually made into the products with the same flavor and alcohol content as regular brand, so the identification for t... The identification of liquor brands is very important for food safety. Most of the fake liquors are usually made into the products with the same flavor and alcohol content as regular brand, so the identification for the liquor brands with the same flavor and the same alcohol content is essential. However, it is also difficult because the components of such liquor samples are very similar. Near-infrared (NIR) spectroscopy combined with partial least squares discriminant analysis (PLS-DA) was applied to identification of liquor brands with the same flavor and alcohol content. A total of 160 samples of Luzhou Laojiao liquor and 200 samples of non-Luzhou Laojiao liquor with the same flavor and alcohol content were used for identification. Samples of each type were randomly divided into the modeling and validation sets. The modeling samples were further divided into calibration and prediction sets using the Kennard-Stone algorithm to achieve uniformity and representativeness. In the modeling and validation processes based on PLS-DA method, the recognition rates of samples achieved 99.1% and 98.7%, respectively. The results show high prediction performance for the identification of liquor brands, and were obviously better than those obtained from the principal component linear discriminant analysis method. NIR spectroscopy combined with the PLS-DA method provides a quick and effective means of the discriminant analysis of liquor brands, and is also a promising tool for large-scale inspection of liquor food safety. 展开更多
关键词 IDENTIFICATION of LIQUOR Brands near-infrared spectroscopy Partial Least SQUARES DISCRIMINANT analysis Principal Component Linear DISCRIMINANT analysis
暂未订购
Application of near-infrared spectroscopy for the rapid analysis of Lonicerae Japonicae Flos solution extracted by water 被引量:2
5
作者 Xue Xiao Jinfang Ma +5 位作者 Fahuan Ge Xiangdong Zhang Huihua Yang Qionghin Liang Yiming Wang Guoan Luo 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2014年第4期42-50,共9页
A rapid quantitative analytical method for three components of Lonicerae Japornicae Flos solution(Lonicera Japonica Thumb.)extracted by water was developed using near-infrared(NIR)spectroscopy and the partial least-sq... A rapid quantitative analytical method for three components of Lonicerae Japornicae Flos solution(Lonicera Japonica Thumb.)extracted by water was developed using near-infrared(NIR)spectroscopy and the partial least-squares(PLS)method.The NIR spectra of 81 samples collected from a production line were obtained.The concentrations of secologanic acid,chlorogenicacid and galuteolin were detemmined by using high-performance liquid chromatography-diodearray detection as the reference method.Several pretreatment methods for the NIR spectra wereusedi during PLS calibration.The most appropriate latent variable number of the PLS factor wasselected based on the standard error of cross-validation(SECV).The performance of the finalPLS models was evaluated according to SECV,standard error of predliction(SEP)and deter-mination coeficient(R^(2)).The compounds secologanic acid,chlorogenic acid and galuteolin hadSEP values of 0.030,0.061 and 1.668μg/mL,respectively and R^(2) values over 0.85.This workshows that NIR spectroscopy is a rapid and convenient method for the analysis of LoniceraeJaponicae Flos solution extracted by water.The proposed method can help in the application ofprocs analytical technology in the pha maceutical industry,particularly in tra ditional Chinesemedicine injections. 展开更多
关键词 Lonicerae Japonicae Flos Qingkailing injection near-infrared partial least-squares rapid analysis
原文传递
Discriminant Analysis of Liquor Brands Based on Moving-Window Waveband Screening Using Near-Infrared Spectroscopy 被引量:6
6
作者 Jie Zhong Jiemei Chen +1 位作者 Lijun Yao Tao Pan 《American Journal of Analytical Chemistry》 2018年第3期124-133,共10页
Partial least squares discriminant analysis (PLS-DA) with integrated moving-window (MW) waveband screening was applied to the discriminant analysis of liquor brands with near-infrared (NIR) spectroscopy. Luzhou Laojia... Partial least squares discriminant analysis (PLS-DA) with integrated moving-window (MW) waveband screening was applied to the discriminant analysis of liquor brands with near-infrared (NIR) spectroscopy. Luzhou Laojiao, a popular liquor with strong fragrant flavor, was used as the identified liquor brand (160 samples, negative, 52 vol alcoholicity). Liquors of 10 other brands with strong fragrant flavor were used as the interferential brands (200 samples, positive, 52 vol alcoholicity). The Kennard-Stone algorithm was used for the division of modeling samples to achieve uniformity and representativeness. Based on the MW-PLS-DA, a simplified optimal model set with 157 wavebands was further proposed. This set contained five types of wavebands corresponding to the NIR absorption bands of water, ethanol, and other micronutrients (i.e., acids, aldehydes, phenols, and aromatic compounds) in liquor for practical choice. Using five selected simple models with 4775 - 4239, 7804 - 6569, 6264 - 5844, 9435 - 7896, and 12066 - 10373 cm-1, the validation recognition rates were obtained as 99.3% or higher. Results show good prediction performance and low model complexity, and also provided a valuable reference for designing small dedicated instruments. The proposed method is a promising tool for large-scale inspection of liquor food safety. 展开更多
关键词 LIQUOR Brands near-infrared spectroscopy PARTIAL Least SQUARES DISCRIMINANT analysis Moving-Window Waveband SCREENING Simplified Optimal Model Set
暂未订购
Visible and Near-Infrared Spectroscopy with Multi-Parameters Optimization of Savitzky-Golay Smoothing Applied to Rapid Analysis of Soil Cr Content of Pearl River Delta 被引量:3
7
作者 Xiaowen Shi Lijun Yao Tao Pan 《Journal of Geoscience and Environment Protection》 2021年第3期75-83,共9页
Using visible and near-infrared (Vis-NIR) spectroscopy combined with partial least squares (PLS) regression, the rapid reagent-free analysis model for chromium (Cr) content in tideland reclamation soil in the Pearl Ri... Using visible and near-infrared (Vis-NIR) spectroscopy combined with partial least squares (PLS) regression, the rapid reagent-free analysis model for chromium (Cr) content in tideland reclamation soil in the Pearl River Delta, China was established. Based on Savitzky-Golay (SG) smoothing and PLS regression, a multi-parameters optimization platform (SG-PLS) covering 264 modes was constructed to select the appropriately spectral preprocessing mode. The optimal SG-PLS model was determined according to the prediction effect. The selected optimal parameters <em>d, p, m</em> and LV were 2, 6, 23 and 8, respectively. Using the validation samples that were not involved in modeling, the root mean square error (SEP<sub>V</sub>), relative root mean square error (R-SEP<sub>V</sub>) and correlation coefficients (R<sub>P, V</sub>) of prediction were 11.66 mg<span style="white-space:nowrap;">&middot;</span>kg<sup>-1</sup>, 10.7% and 0.722, respectively. The results indicated that the feasibility of using Vis-NIR spectroscopy combined with SG-PLS method to analyze soil Cr content. The constructed multi-parameters optimization platform with SG-PLS is expected to be applied to a wider field of analysis. The rapid detection method has important application values to large-scale agricultural production. 展开更多
关键词 Soil Heavy Metal CHROMIUM Visible and near-infrared spectroscopy Rapid Reagent-Free analysis Savitzky-Golay Smoothing
在线阅读 下载PDF
Reliability of online near-infrared spectroscopy analysis of the ex-traction process of Huatan Qushi decoction for phlegm-dampness constitution
8
作者 Zhao Shipeng Zheng Yanfei +7 位作者 Li Pin Liang Xue Bao Lei Chen Yu Yu Ruoxi Sun Ranran Li Lingru Wang Qi 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2017年第6期804-809,共6页
OBJECTIVE: To establish a quantitative model for the online analysis of hesperidin content in the extraction process of Huatan Qushi decoction for individuals with phlegm-dampness constitution by using near-infrared(N... OBJECTIVE: To establish a quantitative model for the online analysis of hesperidin content in the extraction process of Huatan Qushi decoction for individuals with phlegm-dampness constitution by using near-infrared(NIR) spectroscopy and partial least squares(PLS) methods.METHODS: The reference content of hesperidin, an effective ingredient of Huatan Qushi decoction,was determined using high-performance liquid chromatography(HPLC). The modeling band was selected using synergy interval PLS(Si PLS) algorithms, and a PLS model demonstrating the relationship between NIR predictive values and HPLC reference values was established. The optimal modeling route was selected through global optimization of process trace parameters.RESULTS: The root mean square error of cross-validation was 9.8410. The coefficients of determination of the calibration set and prediction set were0.9860(R2 cal) and 0.9458(R_(cal)~2), respectively. The residual predictive deviation was 3.0115. The parameters demonstrated high predictive capability and reliability. The band was selected via the Si PLS method. There were seven latent variables.CONCLUSION: This study provides a favorable comprehensive evaluation method for variable selection and quality control of the Traditional Chinese Medicine extraction process. 展开更多
关键词 spectroscopy near-infrared LEAST-SQUARES analysis HESPERIDIN PHLEGM DAMPNESS Huatan Qushi DECOCTION
原文传递
DISCRIMINATIVE ANALYSIS OF FUNCTIONAL NEAR-INFRARED SPECTROSCOPY SIGNALS FOR DEVELOPMENT OF NEUROIMAGING BIOMARKERS OF ELDERLY DEPRESSION
9
作者 YE ZHU TIANZI JIANG +1 位作者 YUAN ZHOU LISHA ZHAO 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2010年第1期69-74,共6页
Functional near-infrared spectroscopy(fNIRS)is a neuroimaging technology which is suitable for psychiatric patients.Several fNIRS studies have found abnormal brain activations during cognitive tasks in elderly depress... Functional near-infrared spectroscopy(fNIRS)is a neuroimaging technology which is suitable for psychiatric patients.Several fNIRS studies have found abnormal brain activations during cognitive tasks in elderly depression.In this paper,we proposed a discriminative model of multivariate pattern classification based on fNIRS signals to distinguish elderly depressed patients from healthy controls.This model used the brain activation patterns during a verbal fluency task as features of classification.Then Pseudo-Fisher Linear Discriminant Analysis was performed on the feature space to generate discriminative model.Using leave-one-out(LOO)cross-validation,our results showed a correct classification rate of 88%.The discriminative model showed its ability to identify people with elderly depression and suggested that fNIRS may be an efficient clinical tool for diagnosis of depression.This study may provide the first step for the development of neuroimaging biomarkers based on fNIRS in psychiatric disorders. 展开更多
关键词 Functional near-infrared spectroscopy(fNIRS) Fisher linear discriminant analysis(FLDA) DEPRESSION
原文传递
Near-Infrared Spectroscopy Coupled with Kernel Partial Least Squares-Discriminant Analysis for Rapid Screening Water Containing Malathion
10
作者 Congying Gu Bingren Xiang +1 位作者 Yilong Su Jianping Xu 《American Journal of Analytical Chemistry》 2013年第3期111-116,共6页
Near-infrared spectroscopy coupled with kernel partial least squares-discriminant analysis was used to rapidly screen water containing malathion. In the wavenumber of 4348 cm-1 to 9091 cm-1, the overall correct classi... Near-infrared spectroscopy coupled with kernel partial least squares-discriminant analysis was used to rapidly screen water containing malathion. In the wavenumber of 4348 cm-1 to 9091 cm-1, the overall correct classification rate of kernel partial least squares-discriminant analysis was 100% for training set, and 100% for test set, with the lowest concentration detected malathion residues in water being 1 μg·ml-1. Kernel partial least squares-discriminant analysis was able to have a good performance in classifying data in nonlinear systems. It was inferred that Near-infrared spectroscopy coupled with the kernel partial least squares-discriminant analysis had a potential in rapid screening other pesticide residues in water. 展开更多
关键词 Kernel Partial Least Squares-Discriminant analysis near-infrared spectroscopy MALATHION WATER
暂未订购
Rapid detection of colored and colorless macroand micro-plastics in complex environment via near-infrared spectroscopy and machine learning 被引量:3
11
作者 Hui-Huang Zou Pin-Jing He +4 位作者 Wei Peng Dong-Ying Lan Hao-Yang Xian Fan Lü Hua Zhang 《Journal of Environmental Sciences》 2025年第1期512-522,共11页
To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.Howeve... To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds. 展开更多
关键词 Colorless microplastics near-infrared hyperspectral imaging Plastic identification Partial least squares discriminant analysis Machine learning
原文传递
Development and prospect of near-infrared spectroscopy-assisted schizophrenia diagnosis based on bibliometrics
12
作者 Yan Zhang Hao-Yu Xing Juan Yan 《World Journal of Psychiatry》 SCIE 2025年第1期7-11,共5页
In this editorial,we comment on the recent article by Fei et al exploring the field of near-infrared spectroscopy(NIRS)research in schizophrenia from a bibliometrics perspective.In recent years,NIRS has shown unique a... In this editorial,we comment on the recent article by Fei et al exploring the field of near-infrared spectroscopy(NIRS)research in schizophrenia from a bibliometrics perspective.In recent years,NIRS has shown unique advantages in the auxiliary diagnosis of schizophrenia,and the introduction of bibliometrics has provided a macro perspective for research in this field.Despite the opportunities brought about by these technological developments,remaining challenges require multidi-sciplinary approach to devise a reliable and accurate diagnosis system for schizo-phrenia.Nonetheless,NIRS-assisted technology is expected to contribute to the division of methods for early intervention and treatment of schizophrenia. 展开更多
关键词 BIBLIOMETRICS SCHIZOPHRENIA near-infrared spectroscopy Diagnostic technique Data analysis
暂未订购
Performance Evaluation of a Domestic Brain Tissue Oxygen Saturation Monitor Based on Near-Infrared Spectroscopy
13
作者 Xu Mingdi Huang Silu Chen Yi 《Science International Innovative Medicine》 2025年第4期38-49,共12页
Background:The brain,which constitutes merely 2%of total body weight,receives approximately 15%of cardiac output and consumes about 20%of the body's oxygen,rendering it highly susceptible to hypoxia.Short-term oxy... Background:The brain,which constitutes merely 2%of total body weight,receives approximately 15%of cardiac output and consumes about 20%of the body's oxygen,rendering it highly susceptible to hypoxia.Short-term oxygen deprivation can lead to irreversible damage.Near-infrared spectroscopy(NIRS),operating within the 650–1100 nm wavelength range,enables non-invasive,continuous monitoring of cerebral tissue oxygen saturation(rSO_(2)).It has been extensively utilised in intensive care units,neurosurgery,cardiovascular surgery,and perioperative anaesthesia management.Recent advancements in domestically produced devices have progressed rapidly;however,variations in wavelength,sensor design,and algorithms across different brands mean that measurement values are not interchangeable.The accuracy and sensitivity of these devices necessitate comprehensive validation.Objective:This study aimed to evaluate the measurement performance of the domestically produced cerebral tissue oxygen saturation monitor(MOC200),determine its consistency and clinical applicability compared to the imported device(INVOS5100C),and investigate physiological factors influencing baseline rSO_(2)values.Method:A total of 222 healthy subjects aged 15 to 90 years were enrolled from January to March 2025.rSO_(2)was measured using both the MOC200 and INVOS5100C devices.Device performance was assessed via correlation analysis,linear regression,Bland-Altman agreement analysis,and difference testing.Results:Measurement values from MOC200 and INVOS5100C demonstrated high consistency,with a correlation coefficient of 0.786.Bland-Altman analysis indicated greater agreement for left hemisphere measurements,while right hemisphere and mean values exhibited relatively lower consistency.Age,gender,and haemoglobin levels are the primary factors influencing baseline rSO_(2)values,with haemoglobin showing a positive correlation,whereas increasing age and female gender are associated with lower rSO_(2)levels.Conclusion:The domestically developed MOC200 cerebral tissue oxygen saturation monitor reliably reflects cerebral oxygenation in healthy individuals,exhibiting accuracy and stability comparable to the imported device and demonstrating good measurement consistency.Age,sex,and haemoglobin are key physiological factors influencing baseline rSO_(2)in this population. 展开更多
关键词 Cerebral oxygen saturation near-infrared spectroscopy Domestic device Correlation analysis Consistency analysis
暂未订购
Spectroscopic Analysis of Structural Transformation in Biodiesel Oxidation 被引量:4
14
作者 Wu Jiang Chen Boshui +1 位作者 Fang Jianhua Wang Jiu 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第3期28-32,共5页
The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositio... The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed. 展开更多
关键词 BIODIESEL OXIDATION structural transformation spectroscopic analysis
在线阅读 下载PDF
UV/visible spectroscopic analysis of CO^(3+) and CO^(2+) during the dissolution of cobalt from mixed Co-Cu oxidized ores 被引量:1
15
作者 J. Ndalamo A.F. Mulaba-Bafubiandi B.B. Mamba 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第3期260-269,共10页
The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores ... The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores with diluted H2SO4 and SO2 as a reducing agent resulted in a substantial improvement in the solution based recovery of cobalt. UV/visible spectroscopic analysis of the leached solu-tions indicated that the increased cobalt content in the solution was a result of flushing the acidified cobalt leaching solution with SO2. Fur-thermore, UV/visible spectroscopy confirmed that as SO2 was flushed into the acidified leaching solution, Co3+ bearing minerals were re-duced to the readily soluble Co2+ bearing minerals, and this resulted in the increase of total cobalt in the collected solution. The mechanism of the reduction of Co3+ to Co2+ bearing minerals when SO2 is flushed during the leaching of mixed Co-Cu oxidized ores, including the stability trends of Co3+, Co2+, and Cu2+ complexes, as shown by their UV/visible spectra, are also discussed. 展开更多
关键词 cobalt metallurgy DISSOLUTION LEACHING reaction kinetics spectroscopic analysis
在线阅读 下载PDF
Moving-window bis-correlation coefficients method for visible and near-infrared spectral discriminant analysis with applications 被引量:1
16
作者 Lijun Yao Weiqun Xu +1 位作者 Tao Pan Jiemei Chen 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2018年第2期65-77,共13页
The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The we... The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The well-performed moving window principal component analysis linear discriminant analysis(MWPCA-LDA)was also conducted for comparison.A total of 306 transgenic(positive)and 150 nont ransgenic(negative)leave samples of sugarcane were collected and divided to calibration,prediction,and validation.The diffuse reflection spectra were corected using Savitzky-Golay(SG)smoothing with first-order derivative(d=1),third-degree polynomial(p=3)and 25 smpothing points(m=25).The selected waveband was 736-1054nm with MW-BiCC,and the positive and negative validation recognition rates(V_REC^(+),VREC^(-))were 100%,98.0%,which achieved the same effect as MWPCA-LDA.Another example,the 93 B-thalassemia(positive)and 148 nonthalassemia(negative)of human hemolytic samples were colloctod.The transmission spectra were corrected using SG smoothing withd=1,p=3 and m=53.Using M W-BiCC,many best wavebands were selected(e.g.,1116-1146,17941848 and 22842342nm).The V_REC^(+)and V_REC^(-)were both 100%,which achieved the same effect as MW-PCA-LDA.Importantly,the BICC only required ca lculating correlation cofficients between the spectrum of prediction sample and the average spectra of two types of calibration samples.Thus,BiCC was very simple in algorithm,and expected to obtain more applications.The results first confirmed the feasibility of distinguishing B-thalassemia and normal control samples by NIR spectroscopy,and provided a promising simple tool for large population thalassemia screening. 展开更多
关键词 Visible and near infrared spectroscopic discriminant analysis transgenic sugarcane leaves B-thalassemia moving-window bis-correlation cofficients moving-window principal component analysis linear discriminant analysis.
原文传递
Global Optimization of Norris Derivative Filtering with Application for Near-Infrared Analysis of Serum Urea Nitrogen 被引量:2
17
作者 Yihui Yang Tao Pan Jing Zhang 《American Journal of Analytical Chemistry》 2019年第5期143-152,共10页
Near-infrared (NIR) spectroscopy combined with chemometrics methods was applied to the rapid and reagent-free analysis of serum urea nitrogen (SUN). The mul-partitions modeling was performed to achieve parameter stabi... Near-infrared (NIR) spectroscopy combined with chemometrics methods was applied to the rapid and reagent-free analysis of serum urea nitrogen (SUN). The mul-partitions modeling was performed to achieve parameter stability. A large-scale parameter cyclic and global optimization platform for Norris derivative filter (NDF) of three parameters (the derivative order: d, the number of smoothing points: s and the number of differential gaps: g) was developed with PLS regression. Meantime, the parameters’ adaptive analysis of NDF algorithm was also given, and achieved a significantly better modeling effect than one without spectral pre-processing. After eliminating the interference wavebands of saturated absorption, the modeling performance was further improved. In validation, the root mean square error (SEP), correlation coefficient (RP) for prediction and the ratio of performance to deviation (RPD) were 1.66 mmol?L-1, 0.966 and 4.7, respectively. The results showed that the high-precision analysis of SUN was feasibility based on NIR spectroscopy and Norris-PLS. The global optimization method of NDF is also expected to be applied to other analysis objects. 展开更多
关键词 near-infrared Spectral analysis SERUM UREA Nitrogen Norris DERIVATIVE Filter Norris-Partial Least SQUARES Global Optimization
暂未订购
Application of Grey-correlated Spectral Region Selection in Analysis of Near-infrared Spectra
18
作者 ZHANG Yong XIE Yun-fei ZHAO Bing 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2011年第6期924-928,共5页
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 o... 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. 展开更多
关键词 near-infrared spectroscopy Grey correlation analysis Correlation degree Partial least square
在线阅读 下载PDF
Vibrational Spectroscopic Analysis of Borates in Mother Liquid of Brine after Potassium Separated
19
作者 YU Xiaoping GUO Yafei +1 位作者 WANG Qin DENG Tianlong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期391-392,共2页
It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization
关键词 RATE Vibrational spectroscopic analysis of Borates in Mother Liquid of Brine after Potassium Separated
在线阅读 下载PDF
Spectroscopic Analysis of Spherical Graphite from Xinjiang Altai
20
作者 CHENG Siyu CHUAN Xiuyun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第S1期159-160,共2页
1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high cap... 1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high capacitor material,with a high cost performance(Chuan et al,2012).Spherical 展开更多
关键词 spectroscopic analysis of Spherical Graphite from Xinjiang Altai
在线阅读 下载PDF
上一页 1 2 28 下一页 到第
使用帮助 返回顶部