OPTICAL MATERIALS
·
2015
·
IF 1.981
Fangchao Liu,Qun Han,Tiegen Liu,Yunzhi Yao,Yaofei Chen,Yang Du
Sm 3+ -doped oxy-fluoride (OFSm) powders are prepared by the melt quenching technique and characterized using FE-SEM, optical absorption and emission techniques. Spectroscopic properties of Sm 3+ -doped oxy-fluoride powders with different Sm 3+ concentration and sintering temperature are presented and discussed by using the absorption, emission measurements. The Judd–Ofelt intensity (J–O) parameters ( Ω λ , where λ = 2, 4 and 6), measured from the experimental oscillator strengths of the absorption spectra , are used to evaluate the radiative parameters of the fluorescence transitions. Intense orange emission can be obtained when excited with 325 nm wavelength by increasing the sintering temperature to 1400 °C. Ratio of fluorescence intensities arising from the two closing lying 4 F 3/2 and 4 G 5/2 levels is studied, concentration quenching has been noticed beyond 2 mol% of Sm 3+ ions concentration . The excellent spectroscopic properties along with the outstanding thermal stability suggest that the OFSm03 powders may become an attractive laser material to exhibit efficient visible lasing emission in the orange spectral region.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Situ Mu,Dongxu Sun,Yuxiang Liu,Juan Li,Hongwei Zhang,Jie Wang
Dissolved organic matter (DOM) with complex functional groups affects the trace of binding and transformation of hexavalent chromium (Cr(VI)) in the environment. However, the mechanisms and quantitative indicators are still ambiguous. In this study, the perspectives of spectroscopy with synchronous and excitation-emission matrix (EEM) fluorescence, and ultraviolet-visible (UV–vis) were employed to probe the interaction of DOM and Cr(VI). The spectroscopic parameters with Dslope 240–280 (the slope of the log-transformed absorbance in the range of 240–280 nm), DSlope 325–375 (the slope of the log-transformed absorbance in the range of 325–375 nm), S R (the ratio of the slope of the log-transformed absorption coefficient with 275–295 nm to 350–400 nm), SFI (specific fluorescence intensities), AvgFI/AvgUVA (the ratio of average fluorescence to average UV), and SS (Stokes shift) of UV–vis and fluorescence were extracted to characterize the DOM properties. The UV–vis results showed carboxylic-like and total phenolic/carboxylic-like groups were contributed to the complexation of Cr, which resulted in forming macromolecular aggregates, however, the degree of participation of different functional groups was uneven and the binding sequence depended on the types of fractions especially the ratio of protein. Meanwhile, the EEM results proved interaction between DOM and Cr also affected the hydrophobicity and quantum yield of solutions. In addition, according to the change orders of substances and functional groups by Two-dimensional correlation spectroscopy (2DCOS) analysis, aromatic amino acids substances were much more sensitive binding onto Cr than fulvic-like fractions and humic-like fractions, and the mechanisms for Cr(VI) retention were developed. Statistical analysis results showed that S R and SFI were significantly correlated with the concentration of Cr(VI), and multiple linear regression models were developed to predict concentrations of Cr(VI). Moreover, it was found the goodness of fit of SFI was better than that of S R at low Cr concentrations, but opposite at high concentrations.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2022
·
IF 4.831
Xiao-Qi Jia,Yi Li,Liping Zhang,Yuqing Wu
The taste of different flavor liquor is multifarious, but the same brand liquor with different quality is truth. The essence of supramolecular ethanol–water clusters and their intrinsic structural differences in three kinds of Fenjiu are studied by two-dimensional correlation spectra (2D-COS) of fluorescence and Raman. The 2D-COS of fluorescence reveals the prominent emission peaks of three Fenjiu are apparently different. The central fluorescence peak of Fenjiu (a) is located at 330 nm, corresponding to the cluster of (H 2 O) m (EtOH) n . In Fenjiu (b), the emission peak appears near 310 nm, while those of Fenjiu (c) appear mainly near 310 and 373 nm, corresponding to the clusters of (H 2 O)(EtOH) n and (H 2 O) m (EtOH), respectively. Based on 2D-COS of Raman, the peak of Fenjiu (b) at 3440 cm −1 changes initially, indicating its disorder degree is getting higher with continuous dilution with water. However, along with the dilution of Fenjiu (a) and Fenjiu (c), the peak located near 3200 cm −1 changes in priority, indicating that the degree of association between ethanol and water is high, and the clusters formed there are stable. Therefore, this work provides the combined methods to distinguish different supramolecular sets in Fenjiu , applying liquor differentiation in the future.
研究领域:
食品科学
·
光谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOSYSTEMS ENGINEERING
·
2018
·
IF 2.132
Xueming He,Xiaping Fu,Xiuqin Rao
Model robustness has always been the research focus for near infrared spectroscopy technique. In this study, we compared the model performance of four different kinds of spectra (transmittance, reflectance, absorption ( μ a ) and reduced scattering ( μ′ s )) for the prediction of fat and protein of milk. The protein content of milk in prediction set was totally out of range of fat calibration set. The same happens in the case of the fat content of milk in prediction set and protein calibration set. The aim of this present study was to investigate the effect of the difference of protein content on the robustness of four fat calibration models, and of the difference of fat content on the robustness of four protein calibration models. The single integrating sphere system was first calibrated by using 90 liquid phantoms. The detection accuracy of the calibrated system was externally validated by another 80 phantoms. It turned out that the system can measure the absorption and reduced scattering coefficients with relatively high precision in the range of 780–1073 nm, which gave mean relative errors less than 12% and 5% for μ a and μ′ s respectively. Partial least squares regression (PLSR) and stepwise multiple linear regression (SMLR) models were established, and the results showed that calibration model based on reduced scattering spectra could predict fat with the highest robustness for both regression methods, while the absorption spectra could predict protein content with the highest robustness by using SMLR. The separation of absorption and reduced scattering has great potential in improving the robustness of calibration models.
研究领域:
食品科学
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光谱学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RAMAN SPECTROSCOPY
·
2023
·
IF 2.5
Ping-Shi Wang,Hao Ma,Xiao-Han Xi,Xiaxia Yue,Si-Qi Pan,Maofeng Cao,Guo-Kun Liu,Xiang Wang,Bin Ren
Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) have been widely applied for characterizing biological samples. Nowadays, it is routine to use plastic products for biological sample preparation and analysis during spectral acquisition. However, plastic containers produce undesirable signals severely interfering with the spectra of biological samples, which is neglectable and misleading. Herein, we unveiled the physical and chemical interference of plastic products in the process of Raman spectroscopy characterization. Firstly, we revisited a representative case of interference from polystyrene plastics on normal Raman and SERS spectra of cysteine and demonstrated its physical interference due to misfocusing. Furthermore, we testified SERS spectra of aqueous solution stored in several plastic materials commonly used in biological experiments. The spectra indicate strong spectral interference from the leaching chemicals. To address these problems, we proposed a series of strategies to avoid interference from plastic products in the Raman and SERS characterization of biological samples.
研究领域:
生物化学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Peptide Research and Therapeutics
·
2019
·Vol. 26
·期 4
·1991-1999
·
IF 1.219
Cao Mengjie,Lu Kui,Liu Guangbin,Zhao Dongxin,Qi Jianzhao
Affecting the repair function of RAD51 can effectively reverse tumor resistance to chemotherapy and radiotherapy. There is interaction between RAD51 181−200 and BRCA1 846−871 . Using the computer to simulate single mutation of lysine at 862 position of BRCA1 846−871 , six BRCA1 846−871 mutants with significant interaction with RAD51 181−200 were screened out. These mutant peptides were obtained by 9-fluorenylmethyloxycarbonyl (Fmoc) solid-phase peptide synthesis (SPPS) method. All peptides were purified and characterized by liquid chromatography and ESI-MS. In this study, the interaction between RAD51 181−200 and BRCA1 846−871 or mutant peptides was investigated using circular dichroism spectroscopy (CD) and fluorescence spectroscopy. The CD results shown that the secondary structure change of RAD51 181−200 induced by BRCA1 846−871 , BRCA1 846−871 K862F ( F ), BRCA1 846−871 K862G ( G ), BRCA1 846−871 K862E ( E ) and BRCA1 846−871 K862N ( N ) was obvious, which the α-helix content of RAD51 181−200 decreased from 58.3–36.1%, 58.3–36.2%, 58.3–36.4%, 58.3–36.5% and 58.3–36.0%, respectively. While, the addition of BRCA1 846−871 K862P ( P ) and BRCA1 846−871 K862Y ( Y ) hardly changed the α-helix content of RAD51 181−200 . From the fluorescence results, the binding constants of F and Y are 1.00 × 10 5 M −1 and 1.16 × 10 5 M −1 respectively, which were both larger than that of BRCA1 846−871 (9.01 × 10 2 M −1 ). The binding constant of RAD51 181−200 with E (7.45 × 10 3 M −1 ) is slightly higher than that of BRCA1 846−871 . The binding constants of RAD51 181−200 with P (1.24 × 10 3 M −1 ) and N (1.26 × 10 3 M −1 ) are similar to that of BRCA1 846−871 . However, the K b value of G (1.51 × 10 2 M −1 ) is less than that of BRCA1 846−871 . Comparing all spectral data, F is the most significant one interacting with RAD51 181−200 . These findings could provide direction for peptide processing and application.
研究领域:
生物化学
·
分子生物学
·
肿瘤学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Weimin Dong,Yingjie Sun,Qian Yao,Lintao Liu,Qingbo Wang,Hang Wen,Jing Li,Xinguang Xu,Jiyang Wang,Robert I. Boughton
Single crystal Pr(BO 2 ) 3 with centimeter size was grown successfully by a flux method using 3Li 2 CO 3 -2H 3 BO 3 as a flux. The absorption spectrum , emission spectrum , and luminescence lifetime of the Pr(BO 2 ) 3 crystal were measured. The crystal has a relatively large absorption cross section and full widths at half maximum (FWHM), which is advantageous for energy absorption from a pumping source. The spectrum parameters were calculated based on Judd–Ofelt (J-O) theory, and the effective J-O parameters were determined to be: Ω 2 = 37.47 × 10 20 cm 2 , Ω 4 = 6.80 × 10 20 cm 2 , and Ω 6 = 1.05 × 10 20 cm 2 . Furthermore, the emission cross section for the 3 P 0 → 3 F 2 transition at 650 nm was calculated to be 13.6 × 10 −19 cm 2 . The fluorescence lifetime of the 3 P 0 level was obtained to be 4.5 ns. The Raman spectrum of the crystal was also analyzed in detail. Physical properties such as thermal and chemical stability, hardness, and cleavage properties were explored. The refractive index and electronic structure were calculated by the first-principles method.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
·
2023
·
IF 2.8
Chaosheng Yuan,Jian Wang,Qingqing Yang,Ying Xu,Shiquan Feng,Xiang Zhu,Haining Li
This work is devoted to the pressure-induced structural transformations of amoxicillin by Raman and infrared spectroscopy at pressures up to 10 GPa. The Raman and infrared results indicate that amoxicillin underwent two phase transitions upon compression, specifically phase α → β and β → γ phase transitions at 2.71 GPa and 7.45 GPa. The significant changes of hydrogen bonding are indicated by the softened Raman modes, suggesting that the α → β phase transition may be a molecular layering reorganization process. The retrieved Raman and FT-IR spectra demonstrate that pressure-induced phase transitions are reversible upon decompression from 10 GPa to ambient pressure.
研究领域:
药物化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2016
·
IF 4.82
Pengcheng Hu,Rui Zhang,Xianghai Meng,Haiyan Liu,Chunming Xu,Zhichang Liu
Several amide–AlCl3-based ionic liquid (IL) analogues were synthesized through a one-step method using three different structure amides as donor molecules. The effects of the steric and inductive effects of the methyl group substituted on the N atom on the asymmetric splitting of AlCl3 and the coordination site of the amide were investigated by 27Al NMR, Raman, in situ IR, and UV–vis spectra for these IL analogues. Bidentate coordination through both the O and N atoms was dominant in the N-methylacetamide–AlCl3- and N,N-dimethylacetamide–AlCl3-based IL analogues because of the inductive effect of the methyl group. By contrast, the acetamide–AlCl3-based IL analogue presented mainly in the form of monodentate coordination via the O atom. Compared with monodentate coordination, bidentate coordination was favorable to the asymmetric splitting of AlCl3 with the same amide–AlCl3 molar ratio. Under the influence of the steric and inductive effects of the methyl group, the ionic species percentages in these IL analogues ranked in the following order: N-methylacetamide > N,N-dimethylacetamide > acetamide.
研究领域:
化学
·
材料科学
·
光谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Agronomy-Basel
·
2025
·Vol. 15
·期 8
·1779
·
IF 3.4
Meichen Liu,Shengwei Zhang,Jing Gao,Bo Wang,Kedi Fang,Lu Liu,Shengwei Lv,Qian Zhang
The salinization of agricultural soils is a serious threat to farming and ecological balance in arid and semi-arid regions. Accurate estimation of soil water-soluble ions (calcium, carbonate, magnesium, and sulfate) is necessary for correct monitoring of soil salinization and sustainable land management. Hyperspectral ground-based data are valuable in soil salinization monitoring, but the acquisition cost is high, and the coverage is small. Therefore, this study proposes a two-stage deep learning framework with multispectral remote-sensing images. First, the wavelet transform is used to enhance the Transformer and extract fine-grained spectral features to reconstruct the ground-based hyperspectral data. A comparison of ground-based hyperspectral data shows that the reconstructed spectra match the measured data in the 450–998 nm range, with R2up to 0.98 and MSE = 0.31. This high similarity compensates for the low spectral resolution and weak feature expression of multispectral remote-sensing data. Subsequently, this enhanced spectral information was integrated and fed into a novel multiscale self-attentive Transformer model (MSATransformer) to invert four water-soluble ions. Compared with BPANN, MLP, and the standard Transformer model, our model remains robust across different spectra, achieving an R2of up to 0.95 and reducing the average relative error by more than 30%. Among them, for the strongly responsive ions magnesium and sulfate, R2reaches 0.92 and 0.95 (with RMSE of 0.13 and 0.29 g/kg, respectively). For the weakly responsive ions calcium and carbonate, R2stays above 0.80 (RMSE is below 0.40 g/kg). The MSATransformer framework provides a low-cost and high-accuracy solution to monitor soil salinization at large scales and supports precision farmland management.
研究领域:
遥感
·
土壤科学
·
农业监测
·
深度学习
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Lingyu Han,Fang Ma,Ping He,Qun Zhou,Zhanping Li,Suqin Sun
The characterization of structure of organic salts in complex mixtures has been a difficult problem in analytical chemistry. In the analysis of Scutellariae Radix (SR), the pharmacopoeia of many countries stipulates that the quality control component is baicalin (≥9% by high performance liquid chromatography (HPLC)). The component with highest response in SR was also baicalin detected by liquid chromatography-mass spectrometry (LC-MS). However, in the attenuated total reflection Fourier transform infrared spectroscopy, the carbonyl peak of glucuronic acid of baicalin did not appear in SR. The results of element analysis, time of flight secondary ion mass spectrometry, matrix assisted laser desorption ionization mass spectrometry and solid-state nuclear magnetic resonance all supported the existence of baicalin magnesium salt. Based on this, this study proposes an analysis strategy guided by infrared spectroscopy and combined with multi-spectroscopy techniques to analyze the structure of organic salt components in medicinal plant. It is meaningful for the research of mechanisms, development of new drugs, and quality control.
研究领域:
药学
·
分析化学
·
植物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2023
·
IF 3.8
Chaosheng Yuan,Jian Wang,Ying Xu,Yongfu Liang,Shiquan Feng,Xiang Zhu,Haining Li
This work is devoted to the effect of pressure on the structure of lamivudine by using Raman and infrared spectroscopy in diamond anvil cells. The results showed a transition from tetragonal crystal Form Ⅱ to an unknown Form Ⅲ' at approximately 1.26 GPa, followed by a transition from Form Ⅲ' to Form Ⅳ' at pressure of 7.23 GPa. The phase transitions were marked by unique profiles and pressure-dependent characteristic modes. Pressure-induced changes in structural symmetry led to conformational transition in lamivudine. Furthermore, there was a considerable conformational variation between A and D in lamivudine molecule to maintain structural balance. Spectroscopic measurements indicated that these pressure-induced changes were reversible below approximately 0.1 GPa.
研究领域:
药物化学
·
物理化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）