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The Influence of Ceramic Far-Infrared Ray (cFIR) Irradiation on Water Hydrogen Bonding and its Related Chemo-physical Properties
摘要： The property of water is highly related to the earth's environment and climate change. The fundamental dynamical process of water is include formation and breaking of hydrogen bonds. This dynamic process, so far, is still poorly understood. We investigated weakening of the hydrogen bonds of water after ceramic Far-Infrared Ray (cFIR) irradiation and the resulting effects on physical and chemical properties of water. In this study, the Fourier transform infrared spectroscopy (FT-IR) was used to explore hydrogen bonding change of cFIR-irradiated water; in addition, capillary viscometers, Gas Chromatographs (GC), Differential Scanning Calorimetry (DSC), contact angles, Franz cells, High-Performance Liquid Chromatography (HPLC), and capillary electrophoresis analysis were used to evaluate its physical characteristics, such as viscosity, volatility, temperatures of water crystallization, surface tension, diffusion, hydrogen peroxide dissociation, solubility of solid particles, and changes in pH of acetic acid. The cFIR treated water decreased in viscosity and surface tension (contact angles), but increased in the solubility of solid particles, hydrogen peroxide dissociation, temperatures of water crystallization, and acidity of acetic acid. The weakening of water hydrogen bonds caused by cFIR irradiation is correspondent with our previous medical-biological studies on cFIR.
关键词： Hydrogen bonds,Fourier transform infrared spectroscopy (FT-IR),Contact angle,Ceramic far infrared ray (cFIR),Irradiation water,Solubility,Volatility
更新于2025-09-23 15:23:52
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Chemical Analysis of the Interface between Hybrid Organic-Inorganic Perovskite and Atomic Layer Deposited Al2O3
摘要： Ultrathin metal oxides prepared by atomic layer deposition (ALD) have gained utmost attention as moisture and thermal stress barrier layers in perovskite solar cells (PSCs). We have recently shown that 10 cycles of ALD Al2O3 deposited directly on top of the CH3NH3PbI3-xClx perovskite material, are effective in delivering a superior PSC performance with 18% efficiency (compared to 15% of the Al2O3-free cell) with a long-term humidity-stability of more than 60 days. Motivated by these results, the present contribution focuses on the chemical modification which the CH3NH3PbI3-xClx perovskite undergoes upon growth of ALD Al2O3. Specifically, we combine in situ Infrared (IR) spectroscopy studies during film growth, together with X-ray Photoelectron Spectroscopy (XPS) analysis of the ALD Al2O3/perovskite interface. The IR-active signature of the NH3+ stretching mode of the perovskite undergoes minimal changes upon exposure to ALD cycles, suggesting no diffusion of ALD precursor and co-reactant (Al(CH3)3 and H2O) into the bulk of the perovskite. However, by analyzing the difference between the IR spectra associated with the Al2O3 coated perovskite and the pristine perovskite, respectively, changes occurring at the surface of perovskite are monitored. The abstraction of either NH3 or CH3NH2 from the perovskite surface is observed as deduced by the development of negative N-H bands associated to its stretching and bending modes. The IR investigations are corroborated by XPS study, confirming the abstraction of CH3NH2 from the perovskite surface, whereas no oxidation of its inorganic framework is observed within the ALD window process investigated in this work. In parallel, the growth of ALD Al2O3 on perovskite is witnessed by the appearance of characteristic IR-active Al-O-Al phonon and (OH)-Al=O stretching modes. Based on the IR and XPS investigations, a plausible growth mechanism of ALD Al2O3 on top of perovskite is presented.
关键词： infrared spectroscopy,x-ray photoelectron spectroscopy,atomic layer deposition,Al2O3,perovskite
更新于2025-09-23 15:23:52
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Evaluating the Surface Chemistry of Black Phosphorus during Ambient Degradation
摘要： Black Phosphorus (BP) is emerging as a promising candidate for electronic, optical and energy storage applications, however its poor ambient stability remains a critical challenge. Evaluation of few-layer liquid exfoliated BP during ambient exposure using x-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) allows its surface chemistry to be investigated. Oxidation of liquid exfoliated few-layer BP initially occurs through non-bridging oxide species, which convert to bridging oxide species after ambient exposure. We demonstrate the instability of these bridging oxide species, which undergo hydrolysis to form volatile phosphorus oxides and evaporate from the BP surface. FTIR spectroscopy, scanning transmission electron microscopy and atomic force microscopy were used to confirm the formation of liquid oxides through a continuous oxidation cycle that results in the decomposition of BP. Furthermore, we show that the instability of few-layer BP originates from the formation of bridging oxide species.
关键词： Fourier transform infrared spectroscopy,Black phosphorus,phosphorene,x-ray photoelectron spectroscopy,2D materials,degradation,ambient stability,oxidation
更新于2025-09-23 15:23:52
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Detection of Knot Defects on Coniferous Wood Surface Using Near Infrared Spectroscopy and Chemometrics
摘要： Lumber pieces usually contain defects such as knots, which strongly affect the strength and stiffness. To develop a model for rapid, accurate grading of lumbers based on knots, Douglas fir, spruce-pine-fir (SPF), Chinese hemlock, and Dragon spruce were used. The experiments explored the effects of modelling methods and spectral preprocess methods for knot detection, and investigated the feasibility of using a model built within one species to discriminate the samples from other species, using a novel variable selection method-random frog to select effective wavelengths. The results showed that least squares-support vector machines coupled with first derivative preprocessed spectra achieved best performance for both single and mixed models. Models built within Dragon spruce could be used to classify knot samples from SPF and Chinese hemlock but not Douglas fir, and vice versa. Eight effective wavelengths (1314 nm, 1358 nm, 1409 nm, 1340 nm, 1260 nm, 1586 nm, 1288 nm, and 1402 nm) were selected by RF to build effective wavelengths based models. The sensitivity, specificity, and accuracy in the validation set were 98.49%, 93.42%, and 96.30%, respectively. Good results could be obtained when using data at just eight wavelengths, as an alternative to evaluating the whole spectrum.
关键词： Coniferous wood,Knot detection,Near infrared spectroscopy (NIRS),Random frog algorithm,Least squares-support vector machines (LS-SVM)
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Compact Dual-Mode Bandpass Filter Using Square Loop Resonator with Both Capacitance and Inductance Stubs Loaded
摘要： The discriminant analysis model of different medicinal liquor was established based on Fourier transformed infrared spectroscopy (FT-IR) combined with support vector machine (SVM) and principal component analyses (PCA) with the validation accuracy of 99% and training accuracy of 100%. The model was also tested by the external samples with the prediction accuracy of 97%. The accuracy data of the experimental showed that Fourier transform infrared spectroscopy (FT-IR) can be applied well for the classification of medicinal liquor.
关键词： Medicinal liquor,Qualitative,Fourier Transformed Infrared Spectroscopy (FT-IR),Species
更新于2025-09-23 15:23:52
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Use of near infrared spectroscopy and chemometrics to evaluate the shelf-life of cloudy sonicated apple juice
摘要： Fresh products, such as cloudy apple juice, could be preserved from early spoilage through the application of non-thermal processes such as sonication. However, shelf-life analyses based on microbiological and sensory evaluations are expensive and time consuming. Few studies have applied near infrared spectroscopy to evaluate the quality and decay of apple juices. Here, a feasibility trial was conducted to study the spectral behaviour at 1300–2500 nm combined with chemometric approaches. The shelf-life was monitored during two experiments, a challenge test with juices inoculated with spoilage yeasts (inoculated non-sonicated (INS)) and then submitted to sonication treatments (inoculated sonicated (IS)), and a storage test to evaluate the spoilage on non-inoculated juices (non-inoculated non-sonicated (NINS)) and sonicated non-inoculated juices (non-inoculated sonicated (NIS)). These experiments were investigated at six different refrigeration times 7, 14, 21, 28 and 60 days. Two functions were modelled to describe the behaviours of the first principal component according to the storage time. In agreement with a previous chemical and sensory evaluation, this approach allowed us to highlight shelf-life end points of 7 and 14 days for non-sonicated and sonicated samples, respectively. Three different models were evaluated for classification purposes: (1) sonicated versus non-treated samples, (2) end-point shelf-life evaluation at seven days for the NINS and INS juices and (3) end-point shelf-life discrimination at 14 days for IS and NIS samples. A partial least square-discriminant analysis enabled a group classification with accuracy values ranging from 0.63 to 1.00. The application of a variable importance in projection index to interpret the wavelengths of the spectral features suggests a contribution of organic acids and lipids to the prediction of decay. A canonical discriminant analysis provided a clearer separation of samples according to the storage time, especially in relation to the two time thresholds of 7 and 14 days.
关键词： Apple juice,spoilage,near infrared spectroscopy,shelf-life,sonication
更新于2025-09-23 15:23:52
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A variable importance criterion for variable selection in near-infrared spectral analysis
摘要： Variable selection is a universal problem in building multivariate calibration models, such as quantitative structure-activity relationship (QSAR) and quantitative relationships between quantity or property and spectral data. Significant improvement in the prediction ability of the models can be achieved by reducing the bias induced by the uninformative variables. A new criterion, named as C, is proposed in this study to evaluate the importance of the variables in a model. The value of C is defined as the average contribution of a variable to the model, which is calculated by the statistics of the models built with different combinations of the variables. In the calculation, a large number of partial least squares (PLS) models are built using a subset of variables selected by randomly re-sampling. Then, a vector of the prediction errors, in terms of root mean squared error of cross validation (RMSECV), and a matrix composed of 1 and 0 indicating the selected and unselected variables can be obtained. If multiple linear regression (MLR) is employed to model the relationship between the RMSECVs and the matrix, the coefficients of the MLR model can be used as a criterion to evaluate the contribution of a variable to the RMSECV. To enhance the efficiency of the method, a multi-step shrinkage strategy was used. Comparison with Monte Carlo-uninformative variables elimination (MC-UVE), randomization test (RT) and competitive adaptive reweighted sampling (CARS) was conducted using three NIR benchmark datasets. The results show that the proposed criterion is effective for selecting the informative variables from the spectra to improve the prediction ability of models.
关键词： multivariate calibration,multi-step strategy,variable selection,near-infrared spectroscopy
更新于2025-09-23 15:23:52
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Simultaneous Determination of Clarithromycin, Tinidazole and Omeprazole in Helicure Tablets Using Reflectance Near-Infrared Spectroscopy with the Aid of Chemometry
摘要： A near infrared spectroscopic method for the simultaneous determination of the active principles clarithromycin, tinidazole and omeprazole in a pharmaceutical preparation was developed. The three active principles are quantified using partial least-squares regression methods. The proposed method is applicable over a wide analyte concentration range (80–120%) of labeled content, so it requires careful selection of the calibration set and to ensure thorough homogenization of the product. The method was validated in accordance with the ICH standard validation guidelines for NIR spectroscopy by determining its selectivity, linearity, accuracy, precision and stability. Based on the results, it is an effective alternative to the existing choice (HPLC) for the same purpose.
关键词： Partial least squares,Clarithromycin,Helicure,Near Infrared Spectroscopy,Preprocessing,Genetic algorithm,Multivariate calibration
更新于2025-09-23 15:23:52
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Infrared Spectroscopy of Triatomics for Space Observation || Clathrate Nano-Cages
摘要： Determining the presence and evolution of molecular species and their physicochemical environment in astrophysical media makes high-resolution infrared spectroscopy a powerful investigative tool that would provide a great deal of information on how these molecules behave in their environments. In this chapter, we describe the theoretical models developed to analyze the absorption spectra of a triatomic molecule trapped in a clathrate nano-cage at very low temperatures. The Lakhlifi–Dahoo extended inclusion model allows the determination of the trapping site (cage structure type), position and movements of the molecule in its site. Frequency shifts due to the solid environment can be interpreted using an atom–atom potential model to describe the interaction between the clathrate matrix and the trapped molecule. Moreover, this inclusion model makes it possible to determine the IR spectra and the couplings with the atoms or molecules forming the nano-cage.
关键词： clathrate,nano-cage,inclusion model,infrared spectroscopy,astrophysical media,triatomic molecule
更新于2025-09-23 15:23:52
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Photolysis of PCl <sub/>3</sub> /POCl <sub/>3</sub> with Oxygen Dopant Using 193?nm ArF Excimer at Low Temperatures: Oxygen Insertion through ‘Phosphadioxirane’ Pathway
摘要： Photolysis was performed on PCl3 and POCl3 in the presence of oxygen dopant in Ar matrix at low temperatures using 193 nm ArF excimer laser. The photo irradiation initially facilitated the formation of ozone in situ in the low temperature matrix. For PCl3 + O2 photolysis with 193 nm ArF excimer, initially POCl3 was produced and subsequent oxygen atom insertion on POCl3 generated PO2Cl3. Furthermore, secondary reaction channel opens up in PCl3 + O2 photolysis to form a variety of photoproducts such as POCl, PIIIO2Cl, PVO2Cl and PO3Cl. The insertion of oxygen atom on POCl through phosphadioxirane intermediate generated PIIIO2Cl and the direct oxygen atom addition resulted in PVO2Cl. A successive oxygen insertion on PVO2Cl triggered the PO3Cl generation. The identification of all the photoproducts was confirmed through 18O2 isotopic experiments and quantum chemical computations performed using density functional theory (DFT). Computations carried out at B3LYP level of theory with 6–311 + + G(d,p) basis set were used to correlate the structure of photo products obtained experimentally. Interestingly, photo irradiation of POCl3 with oxygen dopant in Ar matrix @193 nm ArF excimer resulted in the generation of PO2Cl3, PO3Cl3 and PO4Cl3 photo products by a sequential insertion of oxygen atoms through phosphadioxirane intermediate. A compelling evidence for the passage of the reaction through phosphadioxirane intermediate is established through 18O2 isotopic substitution experiments.
关键词： DFT computations,matrix isolation,infrared spectroscopy,photolysis,phosphadioxirane intermediate
更新于2025-09-23 15:23:52