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    3043 results match your criteria Applied spectroscopy[Journal]

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    Spatially Resolved Spectral Powder Analysis: Experiments and Modeling.
    Appl Spectrosc 2018 Jan 1:3702817749839. Epub 2018 Jan 1.
    1 130347 Research Center Pharmaceutical Engineering GmbH, Graz , Austria.
    Understanding the behavior of light in granular media is necessary for determining the sample size, shape, and weight when probing using fiber optic setups. This is required for a correct estimate of the active pharmaceutical ingredient content in a pharmaceutical blend via near-infrared spectroscopy. Several strategies to describe the behavior of light in granular and turbid media exist. Read More

    Method for Identifying Maize Haploid Seeds by Applying Diffuse Transmission Near-Infrared Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817742790. Epub 2017 Jan 1.
    1 Laboratory of High Speed Circuits and Neural Networks of the Institute of Semiconductor, Chinese Academy of Sciences, Beijing, China.
    The identification for haploid seeds is an important process in maize haploid breeding. Thanks to the diffuse transmission (DT) technology of near-infrared (NIR) spectroscopy, maize haploid seeds can be selected automatically using NIR spectrum features. However, the NIR spectra of maize seeds contain a large number of redundant features and noise that will degrade the identification performance. Read More

    Accurate Measurement of the Optical Constants n and k for a Series of 57 Inorganic and Organic Liquids for Optical Modeling and Detection.
    Appl Spectrosc 2017 Jan 1:3702817742848. Epub 2017 Jan 1.
    Pacific Northwest National Laboratory, Richland, WA, USA.
    For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties that include chemical structure, optical band strength, volatility, and viscosity. By obtaining the optical constants, one can model most optical phenomena in media and at interfaces including reflection, refraction, and dispersion. Read More

    Identification of Uranium Minerals in Natural U-Bearing Rocks via Infrared Reflectance Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817743265. Epub 2017 Jan 1.
    1 6865 Pacific Northwest National Laboratory , Richland, WA, USA.
    The identification of minerals, including uranium-bearing species, is often a labor-intensive process using X-ray diffraction (XRD), fluorescence, or other solid-phase or wet chemical techniques. While handheld XRD and fluorescence instruments can aid in field applications, handheld infrared (IR) reflectance spectrometers can now also be used in industrial or field environments, with rapid, nondestructive identification possible via analysis of the solid's reflectance spectrum providing information not found in other techniques. In this paper, we report the use of laboratory methods that measure the IR hemispherical reflectance of solids using an integrating sphere and have applied it to the identification of mineral mixtures (i. Read More

    Enhancement of Laser-Induced Breakdown Spectroscopic Signals in a Liquid Jet with Glow Discharge.
    Appl Spectrosc 2017 Jan 1:3702817738029. Epub 2017 Jan 1.
    12399 School of Physics, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams , Chinese Ministry of Education, Dalian University of Technology, Dalian, China.
    In this work, emission signals of laser-induced breakdown (LIBS) plasma of a flowing liquid jet in the absence and presence of an air-supported glow discharge have been investigated. In combination with a needle-to-needle glow discharge, a Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 5 ns) with power density ∼1010 W/cm2 was used to generate a plasma from a liquid jet. Emission lines of Mg, Ca, Al, Li, Na, and K all showed significant enhancements in the presence of the glow discharge. Read More

    Comparison of an InSb Detector and Upconversion Detector for Infrared Polarization Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817746635. Epub 2017 Jan 1.
    5193 Lund University , Lund, Sweden.
    This paper compares the signal-to-noise ratio obtained using an InSb photodiode for infrared (IR) polarization spectroscopy to that obtained using an upconversion detector, and shows a factor 64 improvement by the change. Upconversion detection is based on using sum frequency generation to move the IR optical signal to near-visible wavelengths to improve the sensitivity. Read More

    Thermal Boundary Layer Effects on Line-of-Sight Tunable Diode Laser Absorption Spectroscopy (TDLAS) Gas Concentration Measurements.
    Appl Spectrosc 2018 Jan 1:3702817752112. Epub 2018 Jan 1.
    39428 Physikalisch-Technische Bundesanstalt, Braunschweig, Germany.
    The effects of thermal boundary layers on tunable diode laser absorption spectroscopy (TDLAS) measurement results must be quantified when using the line-of-sight (LOS) TDLAS under conditions with spatial temperature gradient. In this paper, a new methodology based on spectral simulation is presented quantifying the LOS TDLAS measurement deviation under conditions with thermal boundary layers. The effects of different temperature gradients and thermal boundary layer thickness on spectral collisional widths and gas concentration measurements are quantified. Read More

    An Application for the Quantitative Analysis of Pharmaceutical Tablets Using a Rapid Switching System Between a Near-Infrared Spectrometer and a Portable Near-Infrared Imaging System Equipped with Fiber Optics.
    Appl Spectrosc 2018 Jan 1:3702817752697. Epub 2018 Jan 1.
    2 School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan.
    We present a rapid switching system between a newly developed near-infrared (NIR) spectrometer and its imaging system to select the spot size of a diffuse reflectance (DR) probe. In a previous study, we developed a portable NIR imaging system, known as D-NIRs, which has significant advantages over other systems. Its high speed, high spectral resolution, and portability are particularly useful in the process of monitoring pharmaceutical tablets. Read More

    Raman, Infrared, and Laser-Induced Breakdown Spectroscopy Identification of Particles in Raw Materials.
    Appl Spectrosc 2017 Jan 1:3702817742791. Epub 2017 Jan 1.
    rap.ID Inc., Monmouth Junction, NJ, USA.
    Raw materials need to be of a certain quality with respect to physical and chemical composition. They also need to have no contaminants, including particles, because these could indicate raw material impurities or contaminate the product. Particle identification allows determination of process conditions that caused them and whether the quality of the final product is acceptable. Read More

    Study of Surface Wettability Change of Unconsolidated Sand Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Thermogravimetric Analysis.
    Appl Spectrosc 2018 Jan 1:3702817750640. Epub 2018 Jan 1.
    2 42592 Instituto Mexicano del Petróleo, Colonia San Bartolo Atepehuacán, México.
    The effects exerted by the adsorption of vapors of a non-polar compound (deuterated benzene) and a polar compound (water) on the surface of Ottawa sand and a sample of reservoir sand (Channel), which was previously impregnated with silicon oil or two kinds of surfactants, (2-hydroxyethyl) trimethylammonium oleate (HETAO) and (2-hydroxyethyl)trimethylammonium azelate (HETAA), were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and thermogravimetric analysis (TGA). The surface chemistry of the sandstone rocks was elucidated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Terminal surface groups such as hydroxyls can strongly adsorb molecules that interact with these surface groups (surfactants), resulting in a wettability change. Read More

    Characterizing the Intrinsic Fluorescence Properties of Historical Painting Materials: The Case Study of a Sixteenth-Century Mesoamerican Manuscript.
    Appl Spectrosc 2017 Jan 1:3702817747276. Epub 2017 Jan 1.
    1 Centre de Recherche sur la Conservation (CRC), Muséum National d'Histoire Naturelle, Sorbonne-Universités CNRS, Paris, France.
    Ultraviolet visible (UV-Vis) fluorescence spectroscopy is widely used to study polychrome objects and can help to identify the nature of certain materials when they present specific fluorescent properties. However, given the complexity of the stratified and heterogeneous materials under study, the characterization of an intrinsic fluorescence related to a given constituent (a pigment or a binder composing a paint layer for example) is not straightforward, and the recorded raw data need to be corrected for a number of effects that can influence the detected spectral distribution. The application of standard correction procedures to experimental fluorescence data gathered on the polychromatic surface of the Codex Borbonicus, a 16th-century Aztec manuscript, is described. Read More

    Characterization of Barium Borate Frameworks Using Raman Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817748952. Epub 2017 Jan 1.
    8672 Department of Chemistry, Winston-Salem State University , Winston-Salem, NC, USA.
    Systematic micro-Raman scattering investigations have been carried out on Sm+2 doped 2(BaO)-n(B2O3) matrices for n = 4, 5, 8, and 2(BaO)-(Na2O)-9(B2O3) using the 364 nm excitation of an Ar+ laser. The Raman results have been compared with the known structures of barium tetraborate, barium pentaborate, barium octaborate, and barium sodium nonaborate. An excellent correlation has been found between the BO4/BO3 composition ratios for each product and intensity ratios of the designated BO4 and BO3 Raman peaks. Read More

    Compressive Detection of Highly Overlapped Spectra Using Walsh-Hadamard-Based Filter Functions.
    Appl Spectrosc 2017 Jan 1:3702817738023. Epub 2017 Jan 1.
    306571 Department of Chemistry and Biochemistry, California State Polytechnic University Pomona, Pomona, CA, USA.
    In the chemometric context in which spectral loadings of the analytes are already known, spectral filter functions may be constructed which allow the scores of mixtures of analytes to be determined in on-the-fly fashion directly, by applying a compressive detection strategy. Rather than collecting the entire spectrum over the relevant region for the mixture, a filter function may be applied within the spectrometer itself so that only the scores are recorded. Consequently, compressive detection shrinks data sets tremendously. Read More

    Mid-Infrared Standoff Spectroscopy Using a Supercontinuum Laser with Compact Fabry-Pérot Filter Spectrometers.
    Appl Spectrosc 2018 Jan 1:3702817746696. Epub 2018 Jan 1.
    RECENDT - Research Center for Non Destructive Testing, Linz, Austria.
    Mid-infrared (MIR) supercontinuum (SC) lasers are an attractive new option in the field of IR spectroscopy, especially for standoff detection. Supercontinuum radiation unites high brightness, high spatial coherence, and broadband spectral coverage, thereby surpassing thermal IR sources and challenging quantum cascade lasers. The employed SC source operates in the spectral region of 1. Read More

    System Validation Experiments for Obtaining Tracer Laser-Induced Fluorescence Data at Elevated Pressure and Temperature.
    Appl Spectrosc 2017 Jan 1:3702817746409. Epub 2017 Jan 1.
    4 242752 Department of Mechanical Engineering, University of Connecticut , Storrs, CT, USA.
    This paper presents a set of system validation experiments that can be used to qualify either static or flow experimental systems for gathering tracer photophysical data or conducting laser diagnostics at high pressure and temperature in order to establish design and operation limits and reduce uncertainty in data interpretation. Tests demonstrated here quantify the effect of tracer absorption at the test cell walls, stratification, photolysis, pyrolysis, adequacy of mixing and seeding, and reabsorption of laser light using acetone as the tracer and 282 nm excitation. Results show that acetone exhibits a 10% decrease in fluorescence signal over 36 000 shots at 127. Read More

    An Innovative Approach to Exploit the Reflection Spectroscopy of Liquid Characteristics.
    Appl Spectrosc 2017 Jan 1:3702817744543. Epub 2017 Jan 1.
    Remote Sensing Laboratory, School of Geosciences, Faculty of Exact Sciences, Tel-Aviv University, Tel Aviv, Israel.
    Reflection spectroscopy, in the visible-near-infrared-shortwave infrared region (Vis-NIR-SWIR, 350-2500 nm), is a useful technology to extract chemical and physical properties of materials, but might be useless in identifying the spectral features of transparent or dark opaque liquids. Low reflectance values of a liquid reduce the ability to identify characteristic absorption features at specific wavelengths in the reflectance spectrum. In this study, we present a rapid and easy-to-use method to increase the measured reflectance spectrum and expose characteristic absorption features of a liquid. Read More

    Preprocessing Tools Applied to Improve the Assessment of Aldrin Effects on Prostate Cancer Cells Using Raman Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817746947. Epub 2017 Jan 1.
    1 152690 Chemometrics Group, Department of Analytical Chemistry, Universitat de Barcelona , Barcelona, Spain.
    The study of pollutant effects on living organisms provides information about the possible biological and environmental response to a contaminant. Progression of prostate cancer may be related to exposure to pesticides or other chemical substances. In this work, the effect of the pesticide aldrin on human prostate cancer cells (DU145) is studied using Raman spectroscopy and chemometric techniques. Read More

    Chemometric Methods for Estimating the Strain Hardening Modulus in Polyethylene Resins.
    Appl Spectrosc 2018 Jan 1:3702817745327. Epub 2018 Jan 1.
    2 Department of Chemistry, Oklahoma State University, Stillwater, OK, USA.
    The feasibility of using multiway or N-way partial least square (NPLS) methods to estimate physical properties of 1-butene and 1-hexene polyethylene (PE) copolymers directly from multidimensional data obtained from size exclusion chromatography coupled to a Fourier transform infrared detector (SEC FT-IR) was explored. Digital sample sets of horizontal slices (slabs) of two-dimensional data simulating the molecular weight distribution and the corresponding orthogonal FT-IR spectra were correlated to a particular Y-block response using NPLS. The NPLS results were compared to those obtained through separate estimations using various algorithms and exploratory response surface methods. Read More

    Spatially Resolved Temperature Measurements Above a Burning Wood Pellet Using Diode Laser-Based Two-Line Atomic Fluorescence.
    Appl Spectrosc 2017 Jan 1:3702817746996. Epub 2017 Jan 1.
    225299 Division of Combustion Physics, Lund University, Lund, Sweden.
    Diode laser-based two-line atomic fluorescence (TLAF) thermometry applied to flames of combusting wood pellets is demonstrated. The temperature above burning wood pellets placed in the hot product gas of gallium seeded laminar flames is measured. The calibration-free technique provides spatially resolved temperatures in one dimension with sufficient temporal resolution to resolve all combustion stages of a pellet, even in highly sooting flames. Read More

    CR-39 (PADC) Reflection and Transmission of Light in the Ultraviolet-Near-Infrared (UV-NIR) Range.
    Appl Spectrosc 2017 Jan 1:3702817745071. Epub 2017 Jan 1.
    1 14811 Department of Physics & Astronomy, State University of New York at Geneseo, Geneseo, NY, USA.
    The spectral reflection (specular and diffuse) and transmission of Columbia Resin 39 (CR-39) were measured for incoherent light with wavelengths in the range of 200-2500 nm. These results will be of use for the optical characterization of CR-39, as well as in investigations of the chemical modifications of the polymer caused by ultraviolet (UV) exposure. A Varian Cary 5000 was used to perform spectroscopy on several different thicknesses of CR-39. Read More

    Forensic Drug Identification, Confirmation and Quantification Using Fully Integrated Gas Chromatography with Fourier Transform Infrared Detection and Mass Spectrometric Detection (GC-FT-IR-MS).
    Appl Spectrosc 2018 Jan 1:3702817746964. Epub 2018 Jan 1.
    U.S. Food and Drug Administration, Forensic Chemistry Center, Cincinnati, OH, USA.
    This manuscript is a continuation of a recent study that described the use of fully integrated gas chromatography with direct deposition Fourier transform infrared detection and mass spectrometric detection (GC-FT-IR-MS) to identify and confirm the presence of sibutramine and AB-FUBINACA. The purpose of the current study was to employ the GC-FT-IR portion of the same instrument to quantify these compounds, thereby demonstrating the ability to identify, confirm, and quantify drug substances using a single GC-FT-IR-MS unit. The performance of the instrument was evaluated by comparing quantitative analytical figures of merit to those measured using an established, widely employed method for quantifying drug substances, high performance liquid chromatography with ultraviolet detection (HPLC-UV). Read More

    The Temperature-Dependent Si1-xGe x Raman Shift.
    Appl Spectrosc 2018 Jan 1:3702817744218. Epub 2018 Jan 1.
    4 School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore.
    We formulated the composition and temperature dependence of the Si and Si1-xGe x Raman shift from the perspectives of bond order-length-strength correlation and local bond average approach. It is verified that the Raman shift Δω varies in the form of Δω ∝ zE1/2/ d, with inclusion of bond length d and energy E changing with temperature and composition. Numerical reproduction of the thermally induced Si1-xGe x phonon softening indicates that bond thermal expansion and energy loss dictate the frequency redshift, which resulted in quantitative information on the bond energy and the reference frequencies from which the Raman shifts proceed. Read More

    Characterization of Heat Diffusion Properties of Rubberized Two-Layer Systems Using Open Photoacoustic Cell Spectroscopy.
    Appl Spectrosc 2017 Jan 1:3702817727729. Epub 2017 Jan 1.
    1 42487 Departamento de Física, Universidade Estadual de Maringá, Maringá, PR, Brazil.
    We applied the open photoacoustic cell method operating at high frequency as an efficient and highly precise tool for the measurement of thermal properties of rubberized two-layer systems. The heat-coupling between the two layers is treated using the analogy between thermal and electrical resistances widely used in heat transfer problems. The thermal resistance between the two layers is considered effective and the problem is decoupled for each layer. Read More

    All Fiber-Coupled OH Planar Laser-Induced-Fluorescence (OH-PLIF)-Based Two-Dimensional Thermometry.
    Appl Spectrosc 2017 Jan 1:3702817744519. Epub 2017 Jan 1.
    3 33319 Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson AFB, OH, USA.
    Two-color, planar laser-induced fluorescence (PLIF)-based two-dimensional (2D) thermometry techniques for reacting flows, which are typically developed in the laboratory conditions, face a stiff challenge in their practical implementation in harsh environments such as combustion rigs. In addition to limited optical access, the critical experimental conditions (i.e. Read More

    The Effect of Chain Length on Mid-Infrared and Near-Infrared Spectra of Aliphatic 1-Alcohols.
    Appl Spectrosc 2017 Jan 1:3702817732253. Epub 2017 Jan 1.
    49572 Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
    Effect of the chain length on mid-infrared (MIR) and near-infrared (NIR) spectra of aliphatic 1-alcohols from methanol to 1-decanol was examined in detail. Of particular interest were the spectra-structure correlations in the NIR region and the correlation between MIR and NIR spectra of 1-alcohols. An application of two-dimensional correlation analysis (2D-COS) and chemometric methods provided comprehensive information on spectral changes in the data set. Read More

    Binary Complementary Filters for Compressive Raman Spectroscopy.
    Appl Spectrosc 2018 Jan 7;72(1):69-78. Epub 2017 Nov 7.
    1 8522 Department of Chemistry, Purdue University, West Lafayette, IN, USA.
    The previously described optimized binary compressive detection (OB-CD) strategy enables fast hyperspectral Raman (and fluorescence) spectroscopic analysis of systems containing two or more chemical components. However, each OB-CD filter collects only a fraction of the scattered photons and the remainder of the photons are lost. Here, we present a refinement of OB-CD, the OB-CD2 strategy, in which all of the collected Raman photons are detected using a pair of complementary binary optical filters that direct photons of different colors to two photon counting detectors. Read More

    Nanoscale Ex-Situ Thermal Impulse Sensors for Structural Fire Forensics.
    Appl Spectrosc 2017 Jan 1:3702817734292. Epub 2017 Jan 1.
    Applied Sciences Laboratory, Institute for Shock Physics, Washington State University, Spokane, WA, USA.
    We develop nanoscale ex situ thermal impulse (i.e., the temperature and duration of a heating event) sensors for structural fire forensics using a mixture of two lanthanide-doped oxide precursors (precursor Eu:ZrO2 and precursor Dy:Y2O3) that undergo irreversible phase changes when heated. Read More

    Quantitative Detection of Ethanol/Acetone in Complex Solutions Using Raman Spectroscopy Based on Headspace Gas Analysis.
    Appl Spectrosc 2017 Jan 1:3702817738010. Epub 2017 Jan 1.
    1 Institute of Photonics & Bio-medicine, Graduate School of Science, East China University of Science and Technology, Shanghai, China.
    This paper demonstrated the quantitative detection of ethanol and acetone mixtures in complex solutions with Raman spectroscopy based on headspace gas analysis. By analyzing the volatile components in the headspace, their concentrations in liquid solutions were determined. We constructed our own Raman spectroscopy system to detect the headspace gas quantitatively over a solution in a sealed vial. Read More

    Laser-Induced Breakdown Spectroscopy Analysis of Lead Aerosol in Nitrogen and Air Atmosphere.
    Appl Spectrosc 2017 Jan 1:3702817742314. Epub 2017 Jan 1.
    CNR-ICMATE, Institute of Condensed Matter Chemistry and Technologies for Energy, Milan, Italy.
    In this work, laser-induced breakdown spectroscopy (LIBS) is applied for quantitative measurements of Pb in aerosols. In order to investigate the carrier gas role and, in particular, the effect of O2 addition to the gas itself, measurements are carried out in nitrogen and air atmosphere. Aerosol particles are produced by nebulizing Pb(CH3COO)2 * 3H2O aqueous solutions of known concentration and the atomic line of 405. Read More

    A Newly Designed Infrared Reflection Absorption Spectroscopy System for In Situ Characterization from Ultrahigh Vacuum to Ambient Pressure.
    Appl Spectrosc 2018 Jan 15;72(1):122-128. Epub 2017 Nov 15.
    1 Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry; Key Laboratory of Functional Materials and Devices for Special Environments, 74610 Chinese Academy of Sciences, Urumqi , China.
    We present a novel ultrahigh vacuum (UHV) compatible polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) system that is designed for in situ surface spectroscopic characterization on a transferable single crystalline sample. The innovative design of manipulator rod and high-pressure cell (HPC) ensures free movement of the sample between the preparation chamber and the HPC, and perfect separation of them during high pressure experiments. The pressure in the HPC can be varied from UHV (10-9 mbar) to ambient pressure (1000 mbar) while keeping the preparation chamber under UHV conditions. Read More

    Fluorescence Excitation Spectroscopy for Phytoplankton Species Classification Using an All-Pairs Method: Characterization of a System with Unexpectedly Low Rank.
    Appl Spectrosc 2017 Jan 1:3702817741278. Epub 2017 Jan 1.
    1 Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA.
    An all-pairs method is used to analyze phytoplankton fluorescence excitation spectra. An initial set of nine phytoplankton species is analyzed in pairwise fashion to select two optical filter sets, and then the two filter sets are used to explore variations among a total of 31 species in a single-cell fluorescence imaging photometer. Results are presented in terms of pair analyses; we report that 411 of the 465 possible pairings of the larger group of 31 species can be distinguished using the initial nine-species-based selection of optical filters. Read More

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