April 23rd 2024
To improve the robustness and accuracy of logistic regression identification method, a new Raman spectroscopy identification method was proposed that combines a distributionally robust optimization technique and fused lasso technique with logistic regression. Then, Raman spectroscopy was used to analyze two types of dairy products that were collected for anti-jamming identification testing to verify the effectiveness of the new method.
December 1st 2023
Raman measurements of chromite minerals demonstrated that chromium content could be accurately determined, supporting a possible application of portable Raman devices on Earth or in space for mineral analysis of asteroids and planets.
Investigating a Laser-Induced Titanium Plasma Under an Applied Static Electric Field
We investigate the effect of an applied electric field on the laser-induced titanium plasma for laser induced breakdown spectroscopy (LIBS) for the purpose of assessing electron density with respect to laser energy.
Raman Spectroscopy Analysis of Minerals Based on Feature Visualization
November 1st 2020The advantages of machine-learning methods have been widely explored in Raman spectroscopy analysis. In this study, a lightweight network model for mineral analysis based on Raman spectral feature visualization is proposed. The model, called the fire module convolutional neural network (FMCNN), was based on a convolutional neural network, and a fire-module was introduced to increase the width of the network, while also ensuring fewer trainable parameters in the network and reducing the model’s computational complexity. The visualization process is based on a deconvolution network, which maps the features of the middle layer back to the feature space. While fully exploring the features of the Raman spectral data, it also transparently displays the neural network feature extraction results. Experiments show that the classification accuracy of the model reaches 0.988. This method can accurately classify Raman spectra of minerals with less reliance on human participation. Combined with the analysis of the results of feature visualization, our method has high reliability and good application prospects in mineral classification.
Fungal infections and mycotoxin contamination in food products pose a major threat to the world population. Mycotoxins contaminate approximately 25% of the world’s food products and cause severe health problems through the utilization of affected food products. The major mycotoxins in different foods are aflatoxins, ochratoxins, fumonisins, zearalenone, trichothecenes, and deoxynivalenol. Today, various conventional and nondestructive techniques are available for the detection of mycotoxins across multiple food products. Conventional methods are time-consuming, require chemical reagents, and include many laborious steps. Therefore, nondestructive techniques like near-infrared (NIR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, hyperspectral imaging, and the electronic nose are a priority for online detection of fungal and mycotoxin problems in different food products. In this article, we discuss recent improvements and utilization of different nondestructive techniques for the early detection of fungal and mycotoxin infections in various food products.
Application of WDXRF and FT-IR for Human Tooth Analysis
December 1st 2019In this study, WDXRF and FT-IR are used to analyze a tooth sample of a renal patient, and to compare the results to healthy patients. The quantities of multiple elements are reported using the XRF technique, and FT-IR spectroscopy is used to extract relevant information about the molecular contents of the sample with the important absorption bands identified.
Adsorbate-Induced Morphological Changes of PVD-Deposited Nano Island Film SERS Substrates
October 1st 2019The morphology and gap spacing of nano-island film SERS substrates are key factors defining the properties of analyte‒substrate interactions. These results of the study described here have implications for understanding signal variation in SERS and in designing future SERS assays.
Vibrational Spectroscopy of Individual Aerosol Droplets by Optical Tweezers
April 1st 2019Raman spectroscopy, using optical tweezers, is capable of measuring the size, refractive index, and chemical composition of single aerosol droplets, at picoliter volumes. This information improves our understanding of molecular-level chemical processes within droplets.
SEC–ICP-OES Hyphenation: Speciation and Quantification of Polydimethylsiloxanes at Trace Levels
January 1st 2019Polydimethylsiloxane (PDMS) compounds are ubiquitous; thus it is challenging to develop analytical methods that ensure their absence. A newly developed method combining sizeexclusion chromatography with inductively coupled plasma–optical emission spectroscopy makes it possible to quantify ultratrace levels of PDMS in volatile and nonvolatile organic solvents. A complete range of molecular weights can also be distinguished with this approach.