30 June 2020, Volume 32 Issue 2
    

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  • In situ Raman Evidence of Intermediates Adsorption Engineering by High-Index Facets Control during Hydrogen Evolution Reaction
    The Journal of Light Scattering. 2020, 32(2): 95-101. https://doi.org/10.13883/j.issn1004-5929.202002001
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    Electrocatalytic reduction of water is a promising route to produce hydrogen under mild conditions. High-index facet control is one of the most promising ways to achieve excellent hydrogen evolution reaction (HER)catalytic activity. However, the mechanism of the high-index facet enhancement remains unclear. Here, we combine in situ Raman spectroscopy and theoretical calculation to elucidate the mechanism of HER catalytic performance enhanced by high-index facets on Ti@TiO2 nanosheets. During HER process, water molecules tend to adsorb to the high-index facet surface and then reduce to hydrogen. Our work lays the foundation for future exploration the mechanism of electrocatalysis on transition-metal-based electrocatalysts by in situ Raman spectroscopy in energy and environment-related issues.
  • Preparation of Three-Dimensional (3D) SiO2-Ag Porous Structure and SERS Detection of Volatile Organic Compounds (VOCs)
    The Journal of Light Scattering. 2020, 32(2): 102-107. https://doi.org/10.13883/j.issn1004-5929.202002002
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    Three-dimensional (3D) SiO2-Ag porous composite structure substrate was prepared by depositing Ag nanoparticles into 3D SiO2 xerogel via photochemical reduction method. The material has a large specific surface area, high porosity and a high concentration of silanol (Si-OH) on the surface, which endows the material excellent physical and chemical adsorption, resulting in efficient adsorption and capture of VOCs. The SERS enhancement of the Ag nanoparticles allows the substrate to detect target gas molecules with high sensitivity. The substrate has excellent SERS signal uniformity, take toluene gas detection as an example, the relative standard deviation values (RSD) of the main vibrational peaks of 785 cm-1, 1002 cm-1 and 1210 cm-1 at 20 spots are 1.59 %, 1.40 % and 2.08 %, respectively. The long-term stability test showed that the substrate still retained 77.68 % SERS activity after 40 days. The substrate can detect toluene gas as low as 187 ppm. In addition, the SiO2-Ag substrate successfully achieved highly sensitive detection of two and three mixed gases.
  • Antipsychotic drug poisoning monitoring of clozapine in urine by using coffee ring effect based surface-enhanced Raman spectroscopy
    The Journal of Light Scattering. 2020, 32(2): 108-120. https://doi.org/10.13883/j.issn1004-5929.202002003
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    Antipsychotics are the drugs most often involved in drug poisoning cases, and therefore, therapeutic drug monitoring (TDM) for is necessary safe and effective medication administration of these drugs. In this study, a coffee ring effect-based surface-enhanced Raman spectroscopy (CRE-SERS) method was developed and successfully used to monitor antipsychotic poisoning by using urine samples for the first time. The established method exhibited excellent SERS performance since more hot spots were obtained in the “coffee ring”. Using the optimized CRE-SERS method, the sensitivity was improved one order more than that of the conventional method with reasonable reproducibility. The antipsychotic drug clozapine (CLO) spiked into urine samples at 0.5–50 µg·mL-1 was quantitatively detected, at concentrations above the thresholds for toxicity. The CRE-SERS method allowed CLO and its metabolites to be ultimately distinguished from real poisoning urine samples. The coffee-ring effect would provide more opportunities for practical applications of the SERS-based method. The frequent occurrence of drug poisoning may have created a new area for the application of the CRE-SERS method. It is anticipated that the developed method will also have great potential for other drug poisoning monitoring.
  • Theoretical Study of Adsorption and SERS Spectra of Sulfanilamide on Silver Surfaces
    The Journal of Light Scattering. 2020, 32(2): 121-124. https://doi.org/10.13883/j.issn1004-5929.202002004
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    Raman spectroscopy, as an important spectroscopic tool, can be used for structural characterization of molecules as well as qualitative and quantitative analysis due to high detection sensitivity. Sulfonamides (para-amino-benzenesulfonamide) (PABS) are widely used as a large class of antibiotics. It was noted that there were significant differences between normal Raman spectrum and the SERS spectrum of sulfanilamide in alkaline solutions. Our density functional theory (DFT) calculations provide complete vibrational assignments. The further theoretical results show that for adsorbed sulfonamides(PABS) surface catalytic coupling reaction occurs. The product azo compound is responsible for the observed SERS spectra of adsorbed on silver surfaces.
  • Transparent flexible tape coated AuNPs/ITO substrate for pesticide SERS spectral analysis
    The Journal of Light Scattering. 2020, 32(2): 125-131. https://doi.org/10.13883/j.issn1004-5929.202002005
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    The effective extraction of target analytes from complex surface is of great significance for the extension of surface enhanced Raman scattering (SERS) spectroscopy to practical applications. In this paper, a composite of the gold nanoparticles array (AuNPs) deposited on the surface of indium tin oxide conductive glass (ITO) with good SERS activity is used as a SERS substrate by using a transparent and adhesive tape. A rapid detection method for SERS measurement with pesticide residues was established. Flexible tape was used for direct extraction of the anlytes from actual fruit and vegetable surfaces and then coated onto the gold nanoparticle array (AuNPs/ITO) used as a SERS substrate for SERS spectroscopic analysis. Through a simple “paste, peel and re-paste” process, the analytes can be effectivly collected for SERS measurements, and pesticide residues from fruits and vegetables, such as thiram, can be analyzed rapidly by SERS spectroscopic measurements. This research can provide useful information for the establishment of a relevant detection technique.
  • Detection of Methanol in Oil by Surface-enhanced Raman Spectroscopy
    The Journal of Light Scattering. 2020, 32(2): 132-135. https://doi.org/10.13883/j.issn1004-5929.202002006
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    In this work, the methanol molecule spectrum and the methanol-Ag1 surface-enhanced Raman spectrum were simulated. And a SERS substrate of silver NPs on copper surface was prepared by substitution reaction to detect the concentration of methanol dissolved in transformer oil. Based on this SERS substrate, we effectively detected the Raman signal of methanol in 1 mL/L methanol-oil solution, and the wavenumber of this Raman signal is at 1032 cm-1. Our study provides reference for further study on in situ detection and quantitative analysis of methanol in transformer oil.
  • Raman Spectroscopic Detection of Furfural in Oil Based on Different Extractants
    The Journal of Light Scattering. 2020, 32(2): 136-141. https://doi.org/10.13883/j.issn1004-5929.202002007
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    The reliable operation of power transmission and transformation equipment affects the safety and stability of the power grid. The aging diagnosis of oil-paper insulation equipment is one of the key technologies for on-line monitoring and diagnosis of power transmission and transformation equipment. As an important feature for evaluating the aging state of oil-paper insulation equipment, furfural needs to be accurately detected. Raman spectroscopy based on Raman effect can quickly and accurately detect the dissolved aging characteristics in oil. It is therefore important to increase the sensitivity of the Raman detection of dissolved furfural in oil. In this paper, deionized water was used as extractant to extract and Raman spectroscopy of furfural in oil. Under the same experimental conditions, methanol was used as extractant to find the characteristic Raman peak of the furfural molecule of 1371 cm-1. The Raman spectra were compared on a certain concentration gradient, and the minimum test sample concentrations were 1.38 mg/L and 2.75 mg/L, respectively, and the repeatability test was performed. The comparison results show that the Raman spectroscopy of furfural molecules in oil based on deionized water as extractant has lower detection limit and repeatability than methanol as extractant, which is a rapid and non-destructive test for furfural content in oil. Made a contribution.
  • Aging Stage Discrimination of Oil-Paper Insulation Equipment Based on Raman Spectrum and Improved KNN Algorithms
    The Journal of Light Scattering. 2020, 32(2): 142-147. https://doi.org/10.13883/j.issn1004-5929.202002008
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    Power transformer is an indispensable core component of power system. During the aging process of oil-paper insulation equipment, insulation oil or paper decomposes under the action of electricity or heat to produce various characteristic substances reflecting the aging state of insulation, such as furfural, acetone, methanol, CO, CO2, and dissolves in oil, which contains a lot of aging information of oil-paper insulation. In order to diagnose the aging stage of oil-paper insulation effectively, a large number of aging oil samples were obtained by accelerated thermal aging test. According to the aging days, the samples were divided into 12 categories, and 230 Raman spectra were obtained by Raman spectroscopy. The KNN algorithm is used to predict the class of test samples by Pearson correlation coefficient. Then the Euclidean distance is introduced into the model, and the KNN algorithm is improved. The prediction accuracy reaches 87.92%, and the class prediction bias is reduced.
  • Study on Quantitative Analysis Method of Methanol Raman Spectra in Oil By Extraction Technology
    The Journal of Light Scattering. 2020, 32(2): 148-153. https://doi.org/10.13883/j.issn1004-5929.202002009
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    Accurately detecting the concentration of methanol dissolved in transformer oil is of great importance for diagnosing the aging degradation of insulating paper. In this paper, acetonitrile were selected as extractants, and mixed with transformer oil samples containing different concentrations of methanol to complete the sample pretreatment work. The concentration of methanol in transformer oil samples was determined by Raman spectroscopy. The quantitative analysis method based on the principal component analysis of peak intensity of Raman spectra and the quantitative analysis method based on principal component analysis of peak area of Raman spectra were compared. The results show that the accuracy of fitting and error calculation using Raman spectral peak area as quantitative analysis parameter is higher, especially in the low concentration case concerned, it is helpful for us to detect trace methanol dissolved in transformer oil.
  • Glucose concentration detection based on Raman spectroscopy and improved Extreme Learning Machine
    The Journal of Light Scattering. 2020, 32(2): 159-165. https://doi.org/10.13883/j.issn1004-5929.202002011
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    Raman spectroscopy is widely used in the quantitative analysis of components because of its advantages of fast, simple and nondestructive. Currently, quantitative analysis methods of Raman spectroscopy include Partial Least Squares, Artificial Neural Network, Support Vector Machine, etc. In order to seek new methods, in this paper, the Raman spectroscopy data of 41 groups glucose samples were studied. The Extreme Learning Machine was used for quantitative regression. The optimization algorithms such as Genetic Algorithm, Particle Swarm Optimization Algorithm and Artificial Bee Colony Algorithm were used to improve it. After comparison and analysis，a new type of model was proposed, which called Self Adaption Differential Evolution Artificial Bee Colony Algorithm applied to the Extreme Learning Machine. The model adjusted the mutation rate and crossover rate of differential evolution，which can reduce the influence of the Extreme Learning Machine on local optimization and the differential evolution on parameter dependence. Comparing with the traditional Extreme Learning Machine and other optimization algorithm models, the optimized model evaluation index had a significant boost. Experiment showed that Extreme Learning Machine based on Self Adaption Differential Evolution Artificial Bee Colony Algorithm improved the prediction accuracy and model robustness.
  • Remote Raman Detection Based on Gated-Single-Photon Camera
    The Journal of Light Scattering. 2020, 32(2): 166-170. https://doi.org/10.13883/j.issn1004-5929.202002012
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    In order to develop the remote Raman technology, we independently developed the gated-single-photon camera, and construct the Raman demonstration system by the gated-single-photon camera and low energy, high repeat frequency, sub-nanosecond plused laser. And we detect the Raman signal of chlorobenzene and potassium nitrate which is 0.5 meter away from the focal lens, and the signal is high ratio of signal to noise and easy to distinguish the material by the Raman fringerprint. In this article, we initially demonstrate the advantage and potential of gated-single-photon camera in remote Raman detection. The technique proposed in the article has strong application extensibility, and will be important in security-check and mineral survey, etc.
  • Fabrication and SERS Properties Studies of ZnO/Au Composite film
    The Journal of Light Scattering. 2020, 32(2): 171-178. https://doi.org/10.13883/j.issn1004-5929.202002013
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    In order to study the influence of gold nanoparticles with different concentrations in ZnO/Au composite film on Surface-Enhanced Raman Scattering (SERS), Au nanoparticles were deposited on ZnO film as an active substrate to form ZnO/Au composite film by photoreduction reaction, so on to realize the fabrication of SERS substrate. The properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and EDS elemental analysis, we find that the prepared ZnO films are uniformly densely coated on the glass substrates and the gold nanoparticles are successfully deposited on the ZnO surface. The thickness of the ZnO film was measured by a Step Profiler to be 50 nm. Low concentration Rhodamine B (10-9 M) is used as the probe molecule and we change the concentration of Au nanoparticles for SERS test. The results show that ZnO/Au composite film has good Raman enhancement effect, and we find that the distinct characteristic peaks of Rhodamine B are at positions 620 cm-1, 1282 cm-1, 1355 cm-1, 1502 cm-1, and 1646 cm-1. Comparing the SERS enhanced effect of gold nanoparticles with different concentrations in ZnO/Au composite film on detecting rhodamine B, it is found that the Raman activity enhancement effect is the best at the 3 g·L-1 concentration.
  • Simulation Analysis of Surface-enhanced Raman Scattering Chip Based on the Plasma Waveguide
    The Journal of Light Scattering. 2020, 32(2): 179-183. https://doi.org/10.13883/j.issn1004-5929.202002014
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    In this paper, a surface-enhanced Raman scattering optical fluid chip based on long-range plasma waveguide is designed. The dielectric waveguide is used to excite plasma waveguide. The coupling signal transmit through the plasma waveguide and dielectric waveguide. It may reduce the transmission loss and increase transmission distance. The excitation light of 632.8 nm is used. The gold (Au) is as a plasma waveguide core layer and PTFE is as dielectric optical waveguide core layer. The simulation results show that the dielectric optical waveguide width of 4 μm, thickness of 0.2 μm, plasma waveguide width of 4.5 μm, thickness of 13 nm, the spacing D between two waveguide of 3.1 μm, coupling effect is best. The field intensity is about 1.8024 x 108 and the transmission distance is about 0.3 mm which is twice of used alone the plasma waveguide transmission distance. This study provides a theoretical basis for long - range detection of surface-enhanced Raman microfluidic chip.
  • Fast Intelligent Identification and Exploration of Meat On Site
    The Journal of Light Scattering. 2020, 32(2): 184-188. https://doi.org/10.13883/j.issn1004-5929.202002015
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    "hanging a sheep's head and selling a dog's meat" often happens in real life. How to identify meat quickly and intelligently on site is a challenge. This research chooses a portable Raman spectrometer and a self-assembled film consisting of uniform gold nanoparticles as the signal amplification substrate. Using surface-enhanced Raman spectroscopy (SERS) technology, based on its high sensitivity, rapid, fingerprint identification and other features and advantages, combining with the intelligent algorithm of principal component analysis (PCA) and support vector machine (SVM). Achieving quickly and accurately identify of chicken, cattle, sheep and pig meat. This method provides an idea and a method for fast field testing of food safety.
  • First-principles Study of Phonon Spectra and Thermodynamic Properties of ZnX3(OH)6Cl2 (X=Co,Ni)
    The Journal of Light Scattering. 2020, 32(2): 189-194. https://doi.org/10.13883/j.issn1004-5929.202002016
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    In this paper, the method of density functional theory (DFT) and density functional perturbation theory (DFPT) based on the first principles are used to calculate the crystal structures, phonon spectra and density of modes for ZnCo3(OH)6Cl2 and ZnNi3(OH)6Cl2. Both of them have hexagonal crystal structures. Also, the symmetries and frequencies and thermodynamic properties are analyzed and compared. No imaginary frequencies are presented in the phonon spectra obtained from the theoretical calculation, which indicated that the crystal structures are stable; the results of density of modes showed the contribution of different kinds of atoms. The symmetries and frequencies of Raman active vibration modes are determined, and we also compared them with quantum spin liquid ZnCu3(OH)6Cl2, the results showed that the main positions of Raman peak are close. Finally, the thermodynamic properties calculated and analyzed agree with the laws of physics.
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