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Vis-NIR spectroscopy Combined with Wavelengths Selection by PSO Optimization Algorithm for Simultaneous Determination of Four Quality Parameters and Classification of Soy Sauce
摘要： The performance of Vis-NIR techniques combined with variable select by a simple modified particle swarm optimization (PSO) algorithm for the determination of four quality parameters in soy sauce was evaluated. Compared with full-spectral support vector machine regression (Full-SVMR) and SVMR based on competitive adaptive reweighted sampling (CARS-SVM) method, the application of PSO wavelength selection provided a notably improved SVM regression model. The root-mean-square error of amino acid nitrogen, salt, total acid content, and color ratio obtained by PSO-SVMR are 0.0075 g/100 ml, 0.2176 g/100 ml, 0.0077 g/100 ml, and 0.0506 in predicted sets, respectively. The correlation coefficients of predicted sets obtained by PSO-SVMR reached 0.9997, 0.9462, 0.9996, and 0.9998, respectively. Meanwhile, a classification study constructed with principal component analysis and SVM classification model based on the feature wavelengths selected by PSO shows that Vis-NIR spectra can be used to classify soy sauce according to their brands and quality. The result showed that the Vis-NIR spectroscopy technique based on PSO wavelength selection has high potential to predict the quality parameters in a nondestructive way. This analytical tool may also contribute to the detection of fraud and mislabeling in the soy sauce market and certainly contribute to improvement in quality and reliability of the soy sauce market.
关键词： Quality parameters,Wavelength selection,Modified particle swarm optimization algorithm,Visible and near-infrared spectroscopy,Soy sauce
更新于2025-09-09 09:28:46
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Dielectric, electrical and impedance study of single perovskite Pb(Ni1/3Mn1/3W1/3)O3
摘要： A multiferroic material Pb(Ni1/3Mn1/3W1/3)O3 with ferroelectric and ferromagnetic properties at room temperature is designed for multifunctional applications. A orthorhombic perovskite crystal structure has been assigned for the present perovskite according to the X-ray diffraction patterns. At 1 kHz, dielectric constant (er) increases from 1655 at 298 K to its ?rst maximum 3514 at 457 K referred as magnetic transition. The high values of er in the low frequency range show better dispersion, and with the increase in frequency, a gradual decrease in the er values was observed. The contribution of grain and/or electrode/interface effects in the resistive/capacitive properties was ascertained by the Nyquist plots. An equivalent circuit has been suggested consisting of resistive and capacitive components (R, C, Q) estimates the bulk (grain) and grain boundary resistance and capacitance. The activation energy was found to be greater than 0.2 eV, supporting the conduction mechanism due to hopping of charge carriers.
关键词： Solid-state reaction,Multiferroic material,Dielectric response,Electrochemical impedance spectroscopy,Ceramics
更新于2025-09-09 09:28:46
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Understanding perceived color through gradual spectroscopic variations in electrochromism
摘要： A bias-dependent in situ Raman scattering and UV–Vis absorption spectroscopic change has been correlated with the corresponding color change of an electrochromic device in an attempt to explain how to understand the relationship between actual perceived color and its absorption/transmittance spectra. For this, the bias across an electrochromic device was increased gradually, rather than abruptly turning ON and OFF, to see subtle variations in Raman and absorption spectra due to bias. Raman scattering establishes that viologen changes its oxidation state reversibly between two redox species (EV2? to EV??) as a result of bias-induced dynamic redox process. A gradual variation in Raman and absorption spectra, which shows maximum absorption corresponding to the yellow light, accompanies similar variation in color change of the device as visible by naked eye. These spectroscopic results are correlated with the perceived blue color, in the re?ected light, by the eye to understand the actual reason behind this. Maximum absorption of yellow light by the device resulting in blue appearance has been explained using the concept of additive and subtractive primary colors.
关键词： Viologen,Raman spectroscopy,UV–Vis,Electrochromism
更新于2025-09-09 09:28:46
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Nanolayer Research || Nanolayer Analysis by Photoelectron Spectroscopy
摘要： Photoelectron spectroscopy (PES), or photoemission spectroscopy, is one of the most important and useful techniques for investigating electronic and chemical states in solids, especially in nanolayers because of its high-energy resolution and surface sensitivity [1–5]. The physics behind PES is an application of the photoelectric effect. Through photoelectric ionization by irradiating samples with X-rays, vacuum ultraviolet (VUV) or ultraviolet (UV) light, the energies of the emitted photoelectrons are characteristic of their original electronic and chemical states. Therefore PES is one of the most sensitive and accurate techniques for measuring the energies and shapes of electronic states and molecular orbitals. X-ray photoelectron spectroscopy (XPS) was developed by Kai Siegbahn in 1957 and is used to study the energy levels of atomic core electrons, mainly in solids. Siegbahn referred to the technique as electron spectroscopy for chemical analysis (ESCA), since chemical structure can be determined by analyzing the core levels with small chemical shifts depending on the chemical environment of the atom. Siegbahn was awarded the Nobel Prize in Physics in 1981.
关键词： PES,Kai Siegbahn,ESCA,XPS,Photoelectron spectroscopy,photoelectric effect,electronic states,nanolayers,chemical states
更新于2025-09-09 09:28:46
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In situ Study of EDC/NHS Immobilization on Gold Surface Based on Attenuated Total Reflection Surface-Enhanced Infrared Absorption Spectroscopy (ATR-SEIRAS)
摘要： In this study, the time-dependent reaction between 11-mercaptoundecanoic acid (11-MUA) and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) is precisely characterized using surface enhanced infrared absorption spectroscopy (SEIRAS). According to the high correlation between the spectral results of SEIRAS and the electrochemical behavior, it strongly demonstrates that the EDC/NHS reaction would be obviously interfered by phosphate ions in the neutral pH condition (pH = 7.0).
关键词： EDC/NHS,Attenuated Total Reflection (ATR),Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS)
更新于2025-09-09 09:28:46
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Detection of minced lamb and beef fraud using NIR spectroscopy
摘要： In this study, the feasibility of NIR spectroscopy to detect different types of meat fraud in both minced lamb and beef was investigated. For this, a multivariate chemometric approach was used to identify the most useful pre-processing techniques to discriminate between pure lamb and beef and adulterated samples. The results obtained in this study suggest that it is possible to use NIRS to distinguish pure from adulterated minced meat with acceptable precision and accuracy. Rates of classification between 78.95 and 100% were achieved for the validation sets. Higher % CC samples were obtained for samples mixed with pork, meat of Lidia breed cattle and foal meat than for samples adulterated with chicken, where the lowest rates of classification were achieved in both lamb and beef. Additionally, identification of adulteration of meat of Lidia breed cattle in minced beef at 2% was achieved. Furthermore, best classification results were obtained for minced beef mixed with foal meat with a 100% of samples correctly classified indicating that inclusion of foal meat in minced beef at 1% and higher can be detected by using NIRS. Regarding pre-processing techniques, in general, the most powerful ones to classify both groups of samples (pure and mixed) were those orientated to reduce the scatter, MSC and SNV, and, those to correct peak overlaps, 1st and 2nd Der.
关键词： adulteration detection,NIR spectroscopy,minced lamb,chemometrics,meat fraud,minced beef
更新于2025-09-09 09:28:46
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Composition-dependent xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications
摘要： This work reports the composition dependent microstructure, dielectric, ferroelectric and energy storage properties, and the phase transitions sequence of lead free xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 [xBZT-(1-x)BCT] ceramics, with x = 0.4, 0.5 and 0.6, prepared by solid state reaction method. The XRD and Raman scattering results confirm the coexistence of rhombohedral and tetragonal phases at room temperature (RT). The temperature dependence of Raman scattering spectra, dielectric permittivity and polarization points a first phase transition from ferroelectric rhombohedral phase to ferroelectric tetragonal phase at a temperature (TR-T) of 40 0C and a second phase transition from ferroelectric tetragonal phase - paraelectric pseudocubic phase at a temperature (TT-C) of 110 0C. The dielectric analysis suggests that the phase transition at TT-C is of diffusive type and the BZT-BCT ceramics are a relaxor type ferroelectric materials. The composition induced variation in the temperature dependence of dielectric losses was correlated with full width half maxima (FWHM) of A1, E(LO) Raman mode. The saturation polarization (Ps) ≈ 8.3 μC/cm2 and coercive fields ≈ 2.9 kV/cm were found to be optimum at composition x = 0.6 and is attributed to grain size effect. It is also shown that BZT-BCT ceramics exhibit a fatigue free response up to 105 cycles. The effect of a.c. electric field amplitude and temperature on energy storage density and storage efficiency is also discussed. The presence of high TT-C (110 0C), a high dielectric constant (εr ≈ 12285) with low dielectric loss (0.03), good polarization (Ps) ≈ 8.3 μC/cm2) and large recoverable energy density (W = 121 mJ/cm3) with an energy storage efficiency (η) of 70 % at an electric field of 25 kV/cm in 0.6BZT-0.4BCT ceramics make them suitable candidates for energy storage capacitor applications.
关键词： spontaneous polarization,Raman spectroscopy,dielectric constant,lead free ceramics,Energy storage capacitors,fatigue
更新于2025-09-09 09:28:46
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Investigation on the dynamic characteristics of LIBS for heavy metal Mn in liquid matrix
摘要： Laser-induced breakdown spectroscopy in composition analysis of materials has many advantages over other analytical methods.Based on our Laser Induced Breakdown Spectroscopy (LIBS) survey system of heavy metals in the mixed solution and the optimum experimental parameters, we measured the integrated intensities of partial spectral lines of Mn when the ICCD gate delay time and the sample ?ow rate were ranged from 500ns to 2500ns, 35ml/min to 55ml/min respectively. With increasing the time delay, the electron temperature of the plasma decreases gradually, the electron density decreases ?rstly,then the change amplitude tends to be ?at.As the ?ow rate continue increasing,the electron temperature of plasma increases ?rstly, then the change tends to be ?at, the electron density increase gradually.The element particle density ratio of Mn at ?rst ionization state to ground state and Mn at ?rst ionization state are also obtained respectively. Finally, by comparing the experimental value of spectral line intensity ratio of Mn with the calculated value, the nonexistent conditions of local thermal equilibrium and self-absorption of laser plasma are veri?ed.It provides the suppuration for forward quantitative analysis of the trace heavy metal elements in liquid matrix.
关键词： Liquid matrix,Laser induced breakdown spectroscopy,Elements particle density ratio,Electron temperature,Electron density
更新于2025-09-09 09:28:46
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Rapid subtyping of pathogenic and nonpathogenic Vibrio parahaemolyticus by fourier transform infrared spectroscopy with chemometric analysis
摘要： Vibrio parahaemolyticus which naturally inhabits marine and estuarine environment represents pathogenic strains (virulence genes tdh or trh positive) and non-pathogenic strains (virulence genes negative). In this study, a rapid method for subtyping pathogenic and non-pathogenic V. parahaemolyticus was established using fourier transform infrared (FTIR) spectroscopy with chemometric analysis. This method targeted three strains of genotypes of V. parahaemolyticus including tdh positive, trh positive and virulence gene-negative (nonpathogenic) V. parahaemolyticus. The FTIR absorption spectra between 1800 and 900 cm?1 highlighted the most distinctive variations and were the most useful for characterizing the three bacteria. The successful differentiation and identification of the three bacteria could be accomplished in less than 1 h by FTIR using principal component analysis (PCA), or another cluster model of hierarchical cluster analysis (HCA). The method was verified by analyzing spiked V. parahaemolyticus fish samples. Furthermore, all of ten clinical isolates of V. parahaemolyticus were identified as tdh-positive, none of the clinical isolates were trh-positive, and all of ten environmental isolates were identified as non-pathogenic by the subtyping method, which were confirmed by PCR assays. All data demonstrated that the newly established subtyping method by FTIR is practical, time-saving, labor-saving, specific and cost-effective, especially suitable for the basic laboratories of CDC and port quarantine departments to perform suiveillance and epidemiological traceability of pathogenic V. parahaemolyticus.
关键词： Pathogenicity,Principal component analysis,Fourier transform infrared spectroscopy,Hierarchical cluster analysis,Vibrio parahaemolyticus,Subtype
更新于2025-09-09 09:28:46
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Chemometric methods for classification of clonal varieties of green coffee using Raman spectroscopy and direct sample analysis
摘要： This work presents the development of methods for the classification of clonal varieties of coffee using chemometrics coupled to Raman spectroscopy and direct sample analysis. Spectra were collected directly from each bean in triplicate, and the homogeneity of the sample’s surface was studied. The spectral range between 1200 and 1800 cm?1 is related to organic groups that are relevant for the discrimination of coffee. The main peaks were observed at about 1600 cm?1, 1630 cm?1, 1120 cm?1, and 1200 cm?1. All collected spectra were baseline-aligned, then the preprocessing mean centering (MC) or multiplicative scatter correction (MSC) were used. Linear discriminant analysis (LDA), mixture discriminant analysis (MDA), quadratic discriminant analysis (QDA), regularized discriminant analysis (RDA), partial least squares-discriminant analysis with Bayesian inference (PLS–DA), and soft independent modeling of class analogies (SIMCA) methods were applied and compared. MSC provides more accurate results when compared to MC, which may be attributed to the direct analysis of solid samples that requires correction for radiation scattering. Using MSC, the LDA correctly classified 98.7% of the samples, while MDA, RDA, QDA, PLS–DA, and SIMCA corrected classified 100% of the samples. On the other hand, using MC, correct classification of the samples was 62.7% for LDA, 70.7% for MDA, 62.7% for RDA, 62.7% for QDA, 61.3% for PLS–DA, and 97.3% for SIMCA.
关键词： Raman Spectroscopy,Coffee Classification,Pattern Recognition
更新于2025-09-09 09:28:46