ATR Method Research Articles

Antibacterial and antiviral activities of transparent PVA coating films prepared by using solutions containing eluted ions from rare earth iodates

AbstractAfter powders of three rare earth iodates (Ce(IO3)4, Ce(IO3)3, δ-La(IO3)3) were dispersed in water, the constituent ions were eluted. After filtration, polyvinyl alcohol was dissolved in the filtrated solution. Then the solution was flow-coated to form coating films on glass substrates. The obtained coating films exhibited high transmittance in the visible wavelength range. IO3− was confirmed from the IR spectra measured using the ATR method. Fine precipitates were observed in the coating. The amount was greater on the surface than inside. The coating films prepared from Ce(IO3)3 and δ-La(IO3)3 possessed high antibacterial and antiviral activities against Escherichia coli, Staphylococcus aureus, bacteriophage Qβ, and bacteriophage Φ6 in the dark. Moreover, they inactivated viruses adsorbed from the gas phase.

ATR-far-ultraviolet spectroscopy: a challenge to new σ chemistry.

This review reports the recent progress on ATR-far ultraviolet (FUV) spectroscopy in the condensed phase. ATR-FUV spectroscopy for liquids and solids enables one to explore various topics in physical chemistry, analytical chemistry, nanoscience and technology, materials science, electrochemistry, and organic chemistry. In this review, we put particular emphasis on the three major topics: (1) studies on electronic transitions and structures of various molecules, which one cannot investigate via ordinary UV spectroscopy. The combined use of ATR-FUV spectroscopy and quantum chemical calculations allows for the investigation of various electronic transitions, including σ, n-Rydberg transitions. ATR-FUV spectroscopy may open a new avenue for σ-chemistry. (2) ATR-FUV spectroscopy enables one to measure the first electronic transition of water at approximately 160 nm without peak saturation. Using this band, one can study the electronic structure of water, aqueous solutions, and adsorbed water. (3) ATR-FUV spectroscopy has its own advantages of the ATR method as a surface analysis method. ATR-FUV spectroscopy is a powerful technique for exploring a variety of top surface phenomena (∼50 nm) in adsorbed water, polymers, graphene, organic materials, ionic liquids, and so on. This review briefly describes the principles, characteristics, and instrumentation of ATR-FUV spectroscopy. Next, a detailed description about quantum chemical calculation methods for FUV and UV regions is given. The recent application of ATR-FUV-UV spectroscopy studies on electronic transitions from σ orbitals in various saturated molecules is introduced first, followed by a discussion on the applications of ATR-FUV spectroscopy to studies on water, aqueous solutions, and adsorbed water. Applications of ATR-FUV spectroscopy in the analysis of other materials such as polymers, ionic liquids, inorganic semiconductors, graphene, and carbon nanocomposites are elucidated. In addition, ATR-FUV-UV-vis spectroscopy focusing on electrochemical interfaces is outlined. Finally, FUV-UV-surface plasmon resonance studies are discussed.

Fabrication of tricarboxylate-neodymium metal organic frameworks and its nanocomposite with graphene oxide by hydrothermal synthesis for a symmetric supercapacitor electrode material

Efficient energy storage and delivery of electrical energy is necessary for the use of advanced electrode materials in super-capacitors, rendering their development pivotal. We employed simple and economical hydrothermal technique to synthesize Nd-metal organic frameworks (MOFs) and Nd-MOFs/GO composite and evaluated their suitability as electrode materials through comprehensive investigation. Characterizations of the synthesized materials were done by various techniques, including XRD, FTIR (using ATR method) and SEM. Based on the results obtained, it was found that the Nd-MOFs/GO composite-based electrode had a specific capacitance of 633.5 Fg−1 when tested at a current density of 0.3 Ag−1, which is significantly higher than that of Nd-MOFs electrode (11.3 Fg−1). Additionally, electrochemical impedance spectroscopy (EIS) analysis demonstrated the lowest equivalent series resistance (ESR) of 0.8 Ω for the Nd-MOFs/GO electrode. The Nd-MOFs/GO composite electrode exhibited a cyclic stability of 88.76 % after 4000 cycles and coulombic efficiency of 95.1%, when subjected to a current density of 3 Ag−1. Moreover XRD showed that the synthesized hybrid exhibited an improved crystallinity of the hexagonal phase. The FTIR analysis using ATR method confirmed the presence of organic ligands and functional groups in the synthesized materials. The results of our study indicate that the Nd-MOFs/GO hybrid nanocomposite-based electrode material holds potential as a highly efficient candidate for super-capacitor applications. The reported method of synthesizing MOFs provides an effective approach to fabricate new electrode materials with excellent electrochemical characteristics.

Improving Pre-Training and Fine-Tuning for Few-Shot SAR Automatic Target Recognition

SAR-ATR (synthetic aperture radar-automatic target recognition) is a hot topic in remote sensing. This work suggests a few-shot target recognition approach (FTL) based on the concept of transfer learning to accomplish accurate target recognition of SAR images in a few-shot scenario since the classic SAR ATR method has significant data reliance. At the same time, the strategy introduces a model distillation method to improve the model’s performance further. This method is composed of three parts. First, the data engine, which uses the style conversion model and optical image data to generate image data similar to SAR style and realize cross-domain conversion, can effectively solve the problem of insufficient training data of the SAR image classification model. Second is model training, which uses SAR image data sets to pre-train the model. Here, we introduce the deep Brownian distance covariance (Deep BDC) pooling layer to optimize the image feature representation so that the model can learn the image representation by measuring the difference between the joint feature function of the embedded feature and the edge product. Third, model fine-tuning, which freezes the model structure, except the classifier, and fine-tunes it by using a small amount of novel data. The knowledge distillation approach is also introduced simultaneously to train the model repeatedly, sharpen the knowledge, and enhance model performance. According to experimental results on the MSTAR benchmark dataset, the proposed method is demonstrably better than the SOTA method in the few-shot SAR ATR issue. The recognition accuracy is about 80% in the case of 10-way 10-shot.

Post-irradiation degradation of radio-oxidized natural rubber latex films induced by 60Co gamma rays

The present work involves the post-irradiation aging of radio-oxidized natural rubber latex (NRL) films irradiated by 60Co gamma rays. The NRL films underwent the two consecutive processes: irradiation oxidation in air with a dose of 0.1 kGy h−1 (pre-irradiation phase) and radiolysis in argon with a dose of 10 kGy h−1 (post-irradiation phase). The changes of oxygen-containing groups in radio-oxidized NRL films were subsequently analyzed by FTIR (ATR method), XPS, and Raman spectroscopy. Analysis of the EPR spectra of free radicals and macroscope properties (including mechanical and thermodynamic properties) were also carried out. Pre-irradiation of NRL films in air resulted in the rapid formation of various carbonyl and unsaturated carbonyl products related to aliphatic esters, ketones, and carboxylic acids. These were followed by the decomposition of the oxygen-containing functional groups in the post-irradiation phase. In particular, the formation of an enol tautomer of a β-diketone functionality was observed. The increase and decrease of free radicals by EPR analysis were closely related to the crosslinking and degradation of the NRL network structures induced by irradiation. Further analysis indicated that the variations in macroscopic properties of NRL films were attributed to the secondary reactions of free radicals. Mechanistic routes for these irradiation aging processes are proposed and discussed.

SAR ATR Method With Limited Training Data via an Embedded Feature Augmenter and Dynamic Hierarchical-Feature Refiner

SAR ATR Method With Limited Training Data via an Embedded Feature Augmenter and Dynamic Hierarchical-Feature Refiner

A Novel Infrared Spectroscopy Method for Analysis of Stone Dust for Establishing Final Composition of Urolithiasis

BackgroundThe introduction of the holmium laser for lithotripsy and minimally invasive techniques in endoscopy increased the popularity of stone dusting techniques. Retrieving stone pieces for an analysis increases the economic burden of surgery and operative time. Novel methods are needed for the analysis of convenient urolithiasis composition. ObjectiveThis study aims to assess the efficacy of the stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection (FTIR ATR) method for accurate stone composition determination from the dust specimens compared with simultaneously retrieved standard stone fragments. Design, setting, and participantsFrom July 2021 to March 2022, a total of 75 patients who received endoscopic treatment for urolithiasis were included in this study. Outcome measurements and statistical analysisThe accuracy of the FTIR ATR method was assessed via estimates of sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). The results were compared between samples of stone dust and the final stone composition. Results and limitationsTotal or partial biochemical composition agreement was observed in 92.7% of cases and total agreement in 82.4% of cases when stone dust was compared with stone fragments. The highest accuracy rates were obtained for uric acid stones: sensitivity 100%, specificity 98.3%, PPV 90.9%, and NPV 100%. Identification of other types of stones was also of high accuracy, reaching up to 83.3% sensitivity and 100% specificity. ConclusionsThe application of FTIR ATR spectroscopy for a stone dust analysis allows obtaining easy and cost-effective final composition of urolithiasis without a stone fragment analysis. This technique was shown to be feasible, and there is substantial potential for clinical practice. Patient summaryThis study investigates a novel method that determines accurate stone composition without acquiring the pieces of stone during surgery. The results have shown that stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection provides accurate stone composition.

Comparison of two different infrared spectral analysis based evaluation of impact induced shock events of the Chelyabinsk meteorite

Shock metamorphic processes in minerals were observed in the recently fallen Chelyabinsk meteorite and compared with two infrared laboratory methods: DRIFT and ATR based spectral analysis types, attached to a Fourier Transformational Infrared Spectrometer (FTIR). Both of ATR and DRIFT methods have advantages and disadvantages for shock stage identification. However, while the ATR method has wide literature background, the DRIFT method was not used in shock metamorphic research yet, hence this study links ATR spectra with DRIFT spectra to obtain reference for such IR methods in the analysis of shock metamorphism. The results show that shock-based spectral changes could be better followed by the decreasing number of peaks with DRIFT than with ATR data; while the situation is opposite for FWHM values, which better characterizes the shock consequences from ATR data. The DRIFT analyses made from bulk meteorite material. Hence more mineral phases were identified than by separate measurements of ATR. The ATR spectra includes rather major vibration, But with DRIFT the minor bands could be also measured. Hence the other shock indicator, the disappearance of minor bands with increasing shock stage could be better followed by DRIFT. The important shock metamorphic indicator, the FWHM could be identified rather from ATR spectra, as the DRIFT spectra includes small sized peaks, and the FWHM values are near to the spectral resolution of DRIFT spectra. Both of ATR and DRIFT methods show shift of IR bands to higher wavenumber with increasing shock stage. Moreover, the DRIFT method shows the split of some minor bands in case of feldspar and pyroxene due to dimerization of silicate structure.With increasing shock stage one band disappeared and a new one appeared in case of feldspar DRIFT data, while feldspar did not emerge using ATR observations. In case of olivine the major bands shifted by +2… +5 cm−1 using DRIFT and ATR spectra also. In case of pyroxene one band disappeared and new forbidden bands emerged. These results provide starting points to develop shock estimation using DRIFT method too, what is a much more available at various laboratories. However, it is worth mentioning that DRIFT method usually identifies more mineral phases than ATR because of the difference in spatial resolution.

CO2 quantification in silicate glasses using µ-ATR FTIR spectroscopy

Abstract A new method for measurements of high-CO2 concentrations in silicate glasses was established using micro–attenuated total reflectance (µ-ATR) Fourier transform infrared (FTIR) spectroscopy in the mid-IR (MIR) region. We studied two glass/melt compositions, namely leucitite and granite, to cover samples in which CO2 is dissolved as carbonate ions (CO32−) or as CO2 molecules (CO3mol). In the leucitite glasses a carbonate absorption doublet with maxima at 1510 and 1430 cm–1 has shown to clearly separate from aluminosilicate lattice vibrations at lower wavenumbers. Due to the lower sensitivity of the µ-ATR method, we were able to measure high-CO2 contents (cCO2 >0.5 wt%) in experimental silicate glasses that would only be measurable with great difficulties using established transmission MIR measurements due to detector linearity limit effects even with very thin sample wafers. The peak heights of the 1430 cm–1 ATR band (A1430), normalized to the integral of the T-O lattice vibrations (T = Si, Al, Fe) at about 930 cm–1 (Int930) show a linear trend with CO2 contents in the range 0.2–4.3 wt%, yielding a linear correlation with cCO2 (wt%) = 0.4394 ± 0.006·A1430·10000/Int930. The normalization of the CO2 related band to a lattice vibration accounts for variations in the quality of contact between ATR crystal and sample, which has a direct effect on signal intensity. In granitic glasses, where CO2 is dissolved as CO3mol only, the asymmetric stretching vibration at 2350 cm–1 overlaps with the signal of atmospheric, gaseous CO2. As the ATR signal of dissolved CO2 is very weak, the atmospheric signal may dominate the spectrum. Since the absorbance spectrum is calculated by division of the single-channel sample spectrum by a single-channel reference spectrum measured in air, keeping the laboratory and spectrometer atmosphere as constant as possible during spectral acquisition can resolve the problem. Nonetheless, a procedure to subtract the signal of remaining atmospheric CO2 may still be required for the spectral evaluation. We studied a series of 5 granitic glasses with CO3mol contents of 0.08 to 0.27 wt% and found an excellent linear relation between CO2 concentration and lattice vibration normalized ATR intensity of the 2350 cm–1 band: cCO2 (wt%) = 0.2632 ± 0.0016·A2350·10000/Int990. Although the CO3mol concentrations in our granitic glass series can still be analyzed without major difficulties by conventional transmission IR spectroscopy, our data demonstrate the potential of the ATR method for samples with higher CO2 contents or for samples where a high spatial resolution is required (melt inclusions, vesicular or partially crystallized glasses). The lower limits of the ATR method are approximately 0.2 wt% CO2 dissolved as carbonate groups or 0.1 wt% CO2 (or slightly less) dissolved in molecular form.

AC conductivity and modulus studies on (1-x)β-PbF2:xCeO2 composite solid electrolytes

Cubic Lead fluoride [β-PbF2] composite solid electrolyte systems are prepared by dispersing nano CeO2 (< 100nm) in different mol% (5, 10, 15, 20, 25) through the mechanical milling method. XRD and FTIR (ATR method) studies confirm that these are formed in two-phase systems. Scanning Electron Microscope (SEM) images of dispersed systems showed a change in surface morphology with respect to the host. Complex impedance spectroscopy is employed in the frequency range 0.5 to 10 MHz by varying temperatures from 30 to 350°C to study the electric and dielectric properties. Analysis of impedance and modulus spectra revealed the non-Debye nature of these composites. Conductivity measurements on these composites suggest that the frequency exponent (n) in Jonscher’s power law is found to be temperature dependent. The overlapping large polaron tunneling (OLPT) model could be suggested as a suitable hopping mechanism. The variation of the ‘β’ value obtained from the Kohlrausch-Williams-Watts (KWW) function shows a similar variation of ‘n’ in the Jonscher’s power law with temperature.

Effect of Elastic Modulus Gradient on Osteoclastic Metabolic Behavior on Bioabsorbable Substrates Prepared by Welding PLA and PCL

This study aimed to evaluate the effect of the elastic modulus gradient on the osteoclastic metabolic behavior on the functional gradient substrates prepared by welding PLA and PCL. First, the elastic modulus distribution of the substrates with the elastic modulus gradient in the depth-direction were directly evaluated and verified by the tensile and indentation tests. Then, the osteoclasts were cultured on the PLA-side surface of the PCL/PLA functional gradient substrates. The osteoclastic metabolic behavior was evaluated by the ATR method using a FT-IR. As a result, it was confirmed that the elastic modulus of the PCL/PLA functional gradient substrates decreased from the PLA side to the PCL side. This indicates that the functional gradient substrates have the elastic modulus gradient successfully. The FT-IR measurement revealed that the osteoclastic dissolution rate of the substrates increased with the increase of the culture period until 4 weeks, and then decreased at the 5th week. This indicates that the elastic modulus gradient in the depth direction could control the osteoclastic metabolic behavior.

SAR ATR method based on canonical correlations analysis of features extracted by 2D random projection

SAR ATR method based on canonical correlations analysis of features extracted by 2D random projection

Analysis of Asphalt Aging Behavior Evaluation Method Based on Infrared Spectrum

In order to analysis under microscopic scale fast evaluating asphalt asphalt aging mechanism and aging degree, Fourier transform infrared spectroscopy were used respectively to solvent method and ATR method to transmission spectra analysis of matrix asphalt, secondly by ATR method of matrix asphalt tested functional characteristics before and after the RTFOT aging, qualitative and quantitative analysis of the functional groups. The results show that there is no difference between the infrared spectra of the solvent method and the ATR method. Some carbon and sulfur elements in asphalt are oxidized to form carbonyl C=O and sulfoxide S=O functional groups during the aging process, and the oxidation of sulfur element is the main one. The sulfoxide index (SI) and carbonyl index (CI) are well correlated with the penetration degree of asphalt, the correlation coefficient reaches 0.83 and 0.84, respectively. The aging of asphalt increases the sulfoxide index (SI) and carbonyl index (CI), and the asphalt becomes hard and the penetration degree decreases. Infrared spectroscopy can effectively evaluate the aging behavior and degree of asphalt, which provides a new method for rapid detection of aging asphalt.

Application of multi-step approach for comprehensive identification of microplastic particles in diverse sediment samples.

The tremendous increase of plastic production, its intensive usage in packaging, as transport material, and the insufficient management of plastic garbage have led to a rise in microplastic particles as an anthropogenic contaminant in our environment. To develop appropriate management and remediation strategies for this global pollution problem, reliable and consistent analytical procedures for measuring plastics in the complex matrices need to be designed. The applicability of an easy, robust and fast multi-step approach was tested on three sediment samples from riverine, beach and backwater areas of varying origin, grain size and organic matter content, and is reported here. The optimized method included grain size fractionation, density separation and μ-FTIR analyses. Identification was based on two complementary methods of μ -FTIR measurements, the Image mode for small microplastics (<1 mm) and the ATR method for bigger (1-5 mm) particles. The analyses revealed the identification of several polymers in various grain sizes at different pollution levels. Major findings are the dominance of PET particles and the highest frequency of microplastic particles in the midsize fraction of 100-500 μm. Generally, the method was able to reliably detect microplastic particles in several grain size fractions and down to very low contamination levels of approximately. ten particles per 50 g of sediments with different organic matter content and various grain size characteristics. Moreover, the presented multi-step approach represents a fast, easy and less cost-effective method as an alternative to more expensive and time-consuming methods.

Application of spectroscopic and separation techniques to the examination of the chemical composition stability of lipsticks exposed to various factors and storage conditions

In this study, the stability of the chemical composition of lipsticks after exposure to various factors (substrate, time, individual variability, the impact of smoking, the effect of consuming beverages) and storage conditions (laboratory, insolation, without access to light) was examined. The following three analytical methods were used in the study: Attenuated Total Reflection technique (ATR), Gas Chromatography coupled to Mass Spectrometry (GC–MS) and Micellar Electrokinetic Capillary Chromatography (MEKC). Seven red lipsticks characterized by different chemical composition were analyzed. The analysis of variance (ANOVA) was used to estimate the impact of a given factor.It was noticed the lack of influence of individual variability, cigarette smoking and consumed beverages on the stability of the chemical composition of lipsticks. On the other hand, the changes in the chemical composition in lipstick traces depending on the time and storage conditions can be observed – especially when using the GC–MS method. In most cases, the results also indicated the possibility of identifying the lipstick left as a trace, using the ATR and MEKC method even after exposure to various factors and storage conditions. However, the main problem in the case of the ATR analysis is the occurrence of interference originating from the surface on which the trace of lipstick was applied. Ultimately, the conducted research provided evidence for the effectiveness of the MEKC method to the application in forensic science investigation.

A Computational Theory Study of Surface Plasmon Resonance (SPR) Porcine Gelatine Detected Sensor based-on Fe3O4 Nanoparticle—CNT with ATR Method in Kretschmann Configuration

Accurate biomolecular detection can be performed through the Surface Plasmon Resonance (SPR) phenomenon. This study was conducted to simulate the effect of the addition of Fe3O4 nanoparticle and Carbon Nanotube (CNT) in the Kretschmann and Otto configurations using porcine detection sensors. This study employs the equation of reflectance for the investigations of SPR properties (i.e. SPR angle and reflectance value) using Matlab software version 7.12.0. This research was used ATR method with Kretschmann configuration, He-Ne laser on wavelength 632.8 nm, semi-circle prism type BK7 and metal layer of gold nanoparticles. The results of this research can be used in the detection of porcine gelatine by Kretschmann configurations. The best thickness of the gold layer and Fe3O4 layer are 50 nm and 0.05 nm. Moreover, the thickness of SWCNT used is 15 nm. The applied SWCNT is more effective than MWCNT on porcine detection. The SWCNT material also proved to be better used in SPR systems.

Synthesis,Crystal Growth Spectral and Optical Studies on Amino Acid Based New Novel NLO Single Crystal: L-Isoleucinium Phthalate (LIP)

Good quality colourless transparent nonlinear optical single crystals of L-Isoluecinium phthalate (LIP) was grown successfully by slow evaporation solution growth method from aqua solution at room temperature. Single crystals of LIP of dimensions 15mm x 8mm x 5mm were harvested after 50 days. The lattice parameter of grown crystal was studied by single crystal X- ray diffraction analysis and it was confirmed that the grown crystals belong to monoclinic crystal system with noncentrosymmetric space group of C2. Fourier transform infrared spectroscopic (FT-IR) studies was carried out using Jasco FT/IR 6300 Fourier transform infrared spectrometer by ATR method in the range of 400 – 4000 cm-1and it has been used to confirm the vibrational frequencies of various functional groups present in the crystal. Laser induced damage threshold study was carried using Q-Switced Nd: YAG laser and the laser power with the threshold value of 0.323 GW/cm2 also calculated. The UV-Vis-NIR spectroscopic study confirms that the crystal has good optical transparency and the cut off wavelength was found to be 300 nm. The band gap of the grown crystal was determined from the Tauc plot. The nonlinear optical property was confirmed by Kurtz Perry powder technique and it was compared with the standard pure potassium dihydrogen phosphate (KDP) crystals. In addition, a photoluminescence analysis was carried out for LIP crystal

Infrared Spectrometry Options With ATR Method for Oxidation Evaluation of Oils

Abstract Theme Article deals with the use of infrared spectrometry (ATR method) to analyze oxidation, because oxidation plays a role in the self-ignition of oils. As samples were used - sunflower oil, linseed oil. Aim experiment to verify that the infrared spectrometry modified by the ATR method is suitable for the evaluation of the oxidation of liquid substances. Verification of the suitability of the method was performed by comparing the data obtained during the measurement of this experiment with the data verified in other publications. Subsequently, the influence of temperature and time on the oxidation assumed was investigated.

KINETIC REGULARITIES OF POLYCARBONATE ETCHING IN OXYGEN AND AIR PLASMA

Kinetics of etching of cast polycarbonate in the positive column of a DC glow discharge in a flow of oxygen and air were studied at the current range of 20-110 mA and pressure range of 50-300 Pa at different degrees of reactor loading with polymer. The mass loss rates, activation energies of etching process and surface energies were determined. The composition of surface functional groups was obtained by FTIR ATR method and surface morphology was characterized by AFM.

Study of Computational Theory of Surface Plasmon Resonance (SPR) for Porcine Gelatin Detected Sensor Based Nanomaterial Fe3O4–CNT in Otto’s Configuration

Accurate biomolecular detection can be performed through the Surface Plasmon Resonance (SPR) phenomenon. This study was conducted to determine the effect of the addition of Fe3O4 and Carbon Nanotube (CNT) nanomaterials in the Otto configurations and their use as porcine detection sensors. The research was conducted theoretically by finding the equation of reflectance and computationally using Matlab software version 7.12.0 to know SPR angle and reflectance value. This research uses ATR method with Otto configuration. The modeling was finished using HeNe laser light on 632.8 nm wavelength, semi-circle prism type BK7, metal layer of gold nanoparticles. The results of the research can be used in the detection of porcine gelatin by Otto configurations. The best air gap thickness is 30 nm. The best thickness of the gold layer and Fe3O4 layer are 50 nm and 0.05 nm. The applied of MWCNT nanoparticles is not effective in the detection of biomolecules based SPR. While the thickness of SWCNT used is 1 nm. The SWCNT material also proved to be better used in SPR systems. The addition of porcine gelatin layer in the system shows a graphic change in the form of increasing reflectance value and SPR angular shift.