Applied Spectroscopy最新文献

{"title":"Nondispersive Ultraviolet Visible Gas Analyzer for Monitoring Molybdenum Chloride and Oxychloride Precursors During Vapor Deposition Processes.","authors":"James E Maslar, Berc Kalanyan","doi":"10.1177/00037028241268260","DOIUrl":"10.1177/00037028241268260","url":null,"abstract":"<p><p>Nondispersive ultraviolet visible gas analyzer designs were evaluated for monitoring molybdenum-containing chloride and oxychloride precursor delivery during microelectronics vapor deposition processes. The performances of three analyzer designs, which differed only in the bandpass filter employed for wavelength selection, were compared for measuring the partial pressure of molybdenum pentachloride, molybdenum oxytetrachloride (MoOCl₄), and molybdenum dioxydichloride (MoO₂Cl₂). The analyzer's optical response with a 369 nm center wavelength filter for molybdenum pentachloride was determined by measuring the molybdenum pentachloride absorbance as a function of vapor molar density. The calibrated analyzer was transferred to a process line on a deposition chamber and used to measure the molybdenum pentachloride partial pressure during delivery in a flowing carrier gas. The molybdenum pentachloride minimum detectable density was determined to be 1 × 10^-4 mol m^-3 (0.35 Pa for a cell temperature of 145 °C), for data collected at 1 kHz and referenced to a 0.2 s duration background. The analyzer optical response for molybdenum pentachloride with the two other filters and the response for MoOCl₄ and MoO₂Cl₂ with all three filters were simulated with a simple model. These data were used to evaluate the sensitivity and selectivity of analyzers incorporating the different filters to some likely combinations of analytes and interferents.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"289-297"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperspectral Imaging Database of Human Facial Skin.","authors":"Andreia E Gomes, Sérgio M C Nascimento, João M M Linhares","doi":"10.1177/00037028241279323","DOIUrl":"10.1177/00037028241279323","url":null,"abstract":"<p><p>The perceived color of human skin is the result of the interaction of environmental lighting with the skin. Only by resorting to human skin spectral reflectance, it is possible to obtain physical outcomes of this interaction. The purpose of this work was to provide a cured and validated database of hyperspectral images of human faces, useful for several applications, such as psychophysics-based research, object recognition, and material modeling. The hyperspectral imaging data from 29 human faces with different skin tones and sexes, under constant lighting and controlled movements, were described and characterized. Each hyperspectral image, which comprised spectral reflectance of the whole face from 400 to 720 nm in 10 nm steps at each pixel, was analyzed between and within nine facial positions located at different areas of the face. Simultaneously, spectral measurements at the same nine facial positions using conventional local point and/or contact devices were used to ascertain the data. It was found that the spectral reflectance profile changed between skin tones, subjects, and facial locations. Important local variations of the spectral reflectance profile showed that extra care is needed when considering average values from conventional devices at the same area of measurement.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"328-344"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11823275/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding Advanced Attenuated Total Reflection Correction: The Low Absorbance Assumption.","authors":"Thomas G Mayerhöfer, Jürgen Popp","doi":"10.1177/00037028241268024","DOIUrl":"10.1177/00037028241268024","url":null,"abstract":"<p><p>We present an attenuated total reflection (ATR) correction scheme capable of rectifying ATR spectra while considering the polarization state for arbitrary angles of incidence, provided that this angle exceeds the critical angle for the entire ATR spectrum. Due to its reliance on the weak absorption approximation, it cannot achieve perfect correction of the ATR spectra. However, comprehending its functionality may offer valuable insights into the concept behind the weak absorption approximation. Depending on the specific polarization state of an instrument accessory combination, this correction scheme may outperform the proprietary advanced ATR correction authored by ThermoFisher while being as user-friendly, but in contrast to the latter completely transparent with regard to its functionality.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"298-305"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser-Induced Breakdown Spectroscopy as an Accurate Forensic Tool for Bone Classification and Individual Reassignment.","authors":"Jafet Cárdenas-Escudero, David Galán-Madruga, Jorge O Cáceres","doi":"10.1177/00037028241277897","DOIUrl":"10.1177/00037028241277897","url":null,"abstract":"<p><p>This article provides a detailed discussion of the evidence available to date on the application of laser-induced breakdown spectroscopy (LIBS) and supervised classification methods for the individual reassignment of commingled bone remains. Specialized bone chemistry studies have demonstrated the suitability of bone elemental composition as a distinct individual identifier. Given the widely documented ability of the LIBS technique to provide elemental emission spectra that are considered elemental fingerprints of the samples analyzed, the analytical potential of this technique has been assessed for the investigation of the contexts of commingled bone remains for their individual reassignment. The LIBS bone analysis consists of the direct ablation of micrometric portions of bone samples, either on their surface or within their internal structure. To produce reliable, accurate, and robust bone classifications, however, the available evidence suggests that LIBS spectral information must be processed by appropriate methods. When comparing the performance of seven different supervised classification methods using spectrochemical LIBS data for individual reassociation, those employing artificial intelligence-based algorithms produce analytically conclusive results, concretely individual reassociations with 100% accuracy, sensitivity, and robustness. Compared to LIBS, other techniques used for the purpose of interest exhibit limited performance in terms of robustness, sensitivity, and accuracy, as well as variations in these results depending on the type of bones used in the classification. The available literature supports the suitability of the LIBS technique for reliable individual reassociation of bone remains in a fast, simple, and cost-effective manner without the need for complicated sample processing.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"241-259"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142364202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid-Scan Fourier Transform Infrared Difference Spectroscopy with Two-Dimensional Correlation Analysis to Show the Build-Up of Light-Adapted States in Bacterial Photosynthetic Reaction Centers.","authors":"Alberto Mezzetti, Marco Malferrari, Giovanni Venturoli, Francesco Francia, Winfried Leibl, Isao Noda","doi":"10.1177/00037028241304806","DOIUrl":"https://doi.org/10.1177/00037028241304806","url":null,"abstract":"<p><p>Time-resolved, rapid-scan Fourier transform infrared (FT-IR) difference spectra have been recorded upon illumination on photosynthetic reaction centers (RCs) from <i>Rhodobacter sphaeroides</i> under fixed hydration conditions (relative humidity = 76%). Two different illumination schemes were adopted. Whereas the use of a laser flash (duration: 7 ns) made it possible to follow the kinetics of recombination of the light-induced state P⁺Q_A^- to the neutral state PQ_A, the use of a 20.5 s continuous light from a lamp made it possible to follow both the build-up of a steady-state P⁺Q_A^- population and its decay to PQ_A. Comparison between P⁺Q_A^-/PQ_A FT-IR difference spectra obtained under (or 650 ms after) continuous illumination and obtained after one laser flash show small but meaningful differences, reflecting structural changes in the light-adapted state produced by the 20.5 s period of illumination. These differences are strikingly similar to those observed when comparing FT-IR difference spectra reflecting charge separation in photosystem II in light-adapted states and non-light-adapted states (c.f. Sipka et al., \"Light-Adapted Charge-Separated State of Photosystem II: Structural and Functional Dynamics of the Closed Reaction Center\". Plant Cell. 2021. 33(4): 1286-1302). Two-dimensional correlation spectroscopy analysis revealed that in all the observed series of time-resolved FT-IR difference spectra (under illumination, after illumination, and after a laser flash), marker bands at 1749, 1716, and 1668 cm^-1 all evolve synchronously, demonstrating that electron transfer reactions and protein backbone response (at least the one reflected by the 1668 cm^-1 band) are strongly correlated. Conversely, for spectra under and after continuous illumination, many asynchronicities are observed for (still unassigned) bands throughout the whole 1740-1200 cm^-1 region, reflecting a more complicated molecular scenario in the RC upon build-up of the light-adapted state and during its relaxation to the resting neutral state.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241304806"},"PeriodicalIF":2.2,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Local Adaptive Fusion Regression (LAFR) for Local Linear Multivariate Calibration: Application to Large Datasets.","authors":"Robert Spiers, John H Kalivas","doi":"10.1177/00037028241308538","DOIUrl":"https://doi.org/10.1177/00037028241308538","url":null,"abstract":"<p><p>Impeding linear calibration models from accurately predicting target sample analyte amounts are the target sample-wise deviations in measurement profiles (e.g., spectra) relative to calibration samples. Target sample measurement shifts are due to uncontrollable factors, compositely termed matrix effects, such as temperature, instrument drift, and sample composition divergences relative to analyte and other species amounts altering inter and intramolecular interactions. One approach to circumvent the matrix effect matching problem is to use local modeling where a library with thousands of samples and respective reference analyte values is mined for unique calibration sets matched to each target sample, including analyte amounts between calibration and target samples. Current local modeling methods suffer because it is wrongly assumed similar measurements between calibration and target samples translate to a complete locally matched calibration set. Measurements can be similar, but the underlying matrix effects (and analyte amount) can be drastically different. The presented procedure named local adaptive fusion regression (LAFR) solves this matrix effect matching problem with crucial local modeling paradigm shifts. Expertise with LAFR is unnecessary because input hyperparameters are self-optimized. The capabilities of LAFR to form highly dense localized linear calibration sets matched to target samples spectrally and analyte amounts are verified using a well-studied nonlinear benchmark near-infrared (NIR) meat dataset, a NIR sugarcane dataset covering four major process steps with multiple subgroups within, and a NIR soil database of 98 910 samples spanning the contiguous USA. While LAFR is tested on NIR datasets, it is applicable to other measurement systems affected by matrix effects in a broad sense.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241308538"},"PeriodicalIF":2.2,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143021984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Confocal Raman Microscopy for Measuring In Situ Temperature-Dependent Structural Changes in Poly(Ethylene Oxide) Thin Films.","authors":"Miharu Koh, Jay P Kitt, Andrew D Pendergast, Joel M Harris, Shelley D Minteer, Carol Korzeniewski","doi":"10.1177/00037028241310904","DOIUrl":"10.1177/00037028241310904","url":null,"abstract":"<p><p>Crystallization from the melt is a critical process governing the properties of semi-crystalline polymeric materials. While structural analyses of melting and crystallization transitions in bulk polymers have been widely reported, in contrast, those in thin polymer films on solid supports have been underexplored. Herein, in situ Raman microscopy and self-modeling curve resolution (SMCR) analysis are applied to investigate the temperature-dependent structural changes in poly(ethylene oxide) (PEO) films during melting and crystallization phase transitions. By resolving complex overlapping sets of spectra, SMCR analysis reveals that the thermal transitions of 50 µm thick PEO films comprise two structural phases: an ordered crystalline phase and a disordered amorphous phase. The ordered structure of the crystalline PEO film entirely disappears as the polymer is heated; conversely, the disordered structure of the amorphous PEO film reverts to the ordered structure as the polymer is cooled. Broadening of the Raman bands was observed in PEO films above the melting temperature (67 °C), while sharpening of bands was observed below the crystallization temperature (45 °C). The temperatures at which these spectral changes occurred were in good agreement with differential scanning calorimetry (DSC) measurements, especially during the melting transition. The results illustrate that in situ Raman microscopy coupled with SMCR analysis is a powerful approach for unraveling complex structural changes in thin polymer films during melting and crystallization processes. Furthermore, we show that confocal Raman microscopy opens opportunities to apply the methodology to interrogate the structural features of PEO or other surface-supported polymer films as thin as 2 µm, a thickness regime beyond the reach of conventional thermal analysis techniques.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241310904"},"PeriodicalIF":2.2,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142998925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual-Gas Sensor Employing Wavelength-Stabilized Tunable Diode Laser Absorption Spectroscopy and H-Infinity Filtering Algorithm.","authors":"Dingli Xu, Qiannan Cai, Gang Zhang, Qiang Ge, Linguang Xu","doi":"10.1177/00037028241310463","DOIUrl":"https://doi.org/10.1177/00037028241310463","url":null,"abstract":"<p><p>A compact dual-gas sensor based on the two near-infrared distributed feedback diode lasers and a multipass cell has been established for the simultaneous measurement of methane (CH₄) and acetylene (C₂H₂). The time division multiplexing calibration-free direct absorption spectroscopy is used to eliminate the cross interference in the application of multicomponent gas sensors. A wavelength stabilization technique based on the proportion integration differentiation feedback control is developed to suppress laser wavelength drift and an H-infinity (H_∞) filter algorithm to reduce the system noise. The results show that the detection sensitivity of CH₄ and C₂H₂ reaches 39.9 parts per billion (ppb) and 47.3 ppb in the optimal integration time of 556 s and 312 s, respectively. In addition, the 31 consecutive hours measured results of CH₄ in outdoor ambient air show that the proposed detection technology is very suitable for high-precision in-situ measurement of trace gases.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241310463"},"PeriodicalIF":2.2,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142943365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near Real-Time Measurement of Airborne Carbon Nanotubes with Metals Using Raman-Spark Emission Spectroscopy.","authors":"Lina Zheng, Jialin Li, Jing Huang, Wenting Feng, Yuhan Zhan, Dou Liu","doi":"10.1177/00037028241307258","DOIUrl":"https://doi.org/10.1177/00037028241307258","url":null,"abstract":"<p><p>We present a near real-time measurement method that combines Raman and spark emission spectroscopy to quantitatively analyze the molecular structure of airborne single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), as well as detect toxic metals within CNTs. A corona-based aerosol microconcentrator was used for airborne CNTs sampling to enhance the measurement accuracy and sensitivity. The intensity of the characteristic Raman bands of CNTs and atomic emission lines of metals exhibited a linear relationship with the analyte mass, yielding high coefficient <i>R</i>² values. By carefully selecting appropriate signal peaks for calibration, we achieved a limit of detection (LOD) in terms of air concentration as low as 0.09 μg/m³ for SWCNT and 0.81 μg/m³ for MWCNT with a sampling time of 10 min. Additionally, our method exhibited excellent performance in measuring metals, with a mass LOD of 0.8-0.9 ng for Co and Ni and a mass LOD of 35.09 ng for Fe. The method performed well for the measurement of CNT and relevant metal composition with advantages of near real-time monitoring, low LOD, and portable use, making it a valuable tool for various applications in nanomaterial analysis.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241307258"},"PeriodicalIF":2.2,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142943366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Focusing Effects on Laser-Induced Plasma Parameters: Applications to a Graphite Target Under Martian Atmospheric Conditions.","authors":"Kouider Benbaier, Ahmed Abdelmalek, Zeyneb Bedrane, Noureddine Melikechi","doi":"10.1177/00037028241307675","DOIUrl":"https://doi.org/10.1177/00037028241307675","url":null,"abstract":"<p><p>Under various atmospheric conditions, laser-induced breakdown spectroscopy (LIBS) is a powerful technique for elemental analysis, including in Earth- and Mars-like environments. However, understanding the plasma behavior and its dependence on ambient pressure and laser parameters remains a challenge. In this study, a numerical model based on a three-temperature Eulerian radiation framework under non-local thermodynamic equilibrium conditions is employed to investigate the interaction of a nanosecond laser pulse with a graphite target under helium (He) and carbon dioxide (CO₂ atmospheres. The aim is to provide insights into the effects of focusing conditions and ambient pressure (3 to 9 mbar and 1000 mbar) on plasma parameters relevant to both Earth- and Mars-like settings. Our results show that increased ambient pressure significantly enhances electron and ion densities, while the focusing conditions influence the temperature and fluid velocity of plasma species, as well as the spatial distribution and intensity of the plasma, ultimately affecting its diagnostic potential. These findings are critical for optimizing LIBS applications in planetary exploration and contribute to improving quantitative analyses under varying atmospheric compositions.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028241307675"},"PeriodicalIF":2.2,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142920652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}