Статті в журналах: "Materials Spectra"

1

Ilehag, Rebecca, Andreas Schenk, Yilin Huang, and Stefan Hinz. "KLUM: An Urban VNIR and SWIR Spectral Library Consisting of Building Materials." Remote Sensing 11, no. 18 (September 15, 2019): 2149. http://dx.doi.org/10.3390/rs11182149.

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Knowledge about the existing materials in urban areas has, in recent times, increased in importance. With the use of imaging spectroscopy and hyperspectral remote sensing techniques, it is possible to measure and collect the spectra of urban materials. Most spectral libraries consist of either spectra acquired indoors in a controlled lab environment or of spectra from afar using airborne systems accompanied with in situ measurements. Furthermore, most publicly available spectral libraries have, so far, not focused on facade materials but on roofing materials, roads, and pavements. In this study, we present an urban spectral library consisting of collected in situ material spectra with imaging spectroscopy techniques in the visible and near-infrared (VNIR) and short-wave infrared (SWIR) spectral range, with particular focus on facade materials and material variation. The spectral library consists of building materials, such as facade and roofing materials, in addition to surrounding ground material, but with a focus on facades. This novelty is beneficial to the community as there is a shift to oblique-viewed Unmanned Aerial Vehicle (UAV)-based remote sensing and thus, there is a need for new types of spectral libraries. The post-processing consists partly of an intra-set solar irradiance correction and recalculation of reference spectra caused by signal clipping. Furthermore, the clustering of the acquired spectra was performed and evaluated using spectral measures, including Spectral Angle and a modified Spectral Gradient Angle. To confirm and compare the material classes, we used samples from publicly available spectral libraries. The final material classification scheme is based on a hierarchy with subclasses, which enables a spectral library with a larger material variation and offers the possibility to perform a more refined material analysis. The analysis reveals that the color and the surface structure, texture or coating of a material plays a significantly larger role than what has been presented so far. The samples and their corresponding detailed metadata can be found in the Karlsruhe Library of Urban Materials (KLUM) archive.

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2

Latvels, Janis, Raitis Grzibovskis, Aivars Vembris, and Dagnija Blumberga. "Improvement of Solar PV Efficiency. Potential Materials for Organic Photovoltaic Cells." Scientific Journal of Riga Technical University. Environmental and Climate Technologies 12, no. 1 (December 1, 2013): 28–33. http://dx.doi.org/10.2478/rtuect-2013-0013.

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Abstract Organic photovoltaic (OPV) cells are considered as a viable alternative to those energy sources currently in use. In this work three derivatives of original N,N’- dimetilaminobenziliden-1,3-indandione (DMABI) material are presented as potential materials for OPV. The photoconductivity threshold energy was evaluated from the perspective of spectral dependence of photoconductivity quantum efficiency, and the optical energy gap was defined to determine the optical absorption spectra. The absorption spectra of derivatives are blue shifted compared to original DMABI. Use of these derivatives in multilayer solar cells with original DMABI makes it possible to broaden the spectral response range of OPV.

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3

Myers, Daryl R., Keith Emery, and C. Gueymard. "Revising and Validating Spectral Irradiance Reference Standards for Photovoltaic Performance Evaluation." Journal of Solar Energy Engineering 126, no. 1 (February 1, 2004): 567–74. http://dx.doi.org/10.1115/1.1638784.

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In 1982, the American Society for Testing and Materials (ASTM) adopted consensus standards for direct-normal and hemispherical (“global”) tilted solar terrestrial spectra (ASTM E891/E892/G159). These standard spectra were intended to evaluate photovoltaic (PV) device performance and other solar-related applications. The International Standards Organization (ISO) and International Electrotechnical Commission (IEC) adopted these spectra as spectral standards ISO 9845-1 and IEC 60904-3. Additional information and more accurately representative spectra are needed by today’s PV community. Modern terrestrial spectral radiation models, knowledge of atmospheric physics, and measured radiometric quantities are applied to develop new reference spectra under consideration by ASTM.

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4

Kuzmina, D. A., E. Yu Mendosa, E. E. Maiorov, N. S. Narusak, A. I. Sakerina, and L. I. Shalamay. "Experimental studies of optical properties of hard tissues of anterior teeth and modern synthetic filling materials." Stomatology for All / International Dental review, no. 2020 4 (93) (December 2020): 58–62. http://dx.doi.org/10.35556/idr-2020-4(93)58-62.

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The article data on the study of reflection spectra of hard tooth tissues and dental restoration materials are presented. The method of investigation of dental hard tissues and dental restoration materials — the method of diffuse reflection electron spectroscopy is defined. The relevance of the work, since a high level of restoration aesthetics in therapeutic dentistry is important is shown. Reflection spectra of the studied samples on an automated spectrofluorometer “SDL-2” were performed. Spectral dependences of the reflection coefficient of enamel and dentin sections, as well as intact teeth of patients of different ages, were obtained. The spectral dependences of the reflection coefficient of various dental restoration materials were analyzed.

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5

Kuzmina, D. A., E. Yu Mendosa, E. E. Maiorov, N. S. Narusak, A. I. Sakerina, and L. I. Shalamay. "Experimental studies of optical properties of hard tissues of anterior teeth and modern synthetic filling materials." Stomatology for All / International Dental review, no. 2020 4 (93) (December 2020): 58–62. http://dx.doi.org/10.35556/idr-2020-4(93)58-62.

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The article data on the study of reflection spectra of hard tooth tissues and dental restoration materials are presented. The method of investigation of dental hard tissues and dental restoration materials — the method of diffuse reflection electron spectroscopy is defined. The relevance of the work, since a high level of restoration aesthetics in therapeutic dentistry is important is shown. Reflection spectra of the studied samples on an automated spectrofluorometer “SDL-2” were performed. Spectral dependences of the reflection coefficient of enamel and dentin sections, as well as intact teeth of patients of different ages, were obtained. The spectral dependences of the reflection coefficient of various dental restoration materials were analyzed.

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6

Schmitt, J. M., and G. Kumar. "Spectral Distortions in Near-Infrared Spectroscopy of Turbid Materials." Applied Spectroscopy 50, no. 8 (August 1996): 1066–73. http://dx.doi.org/10.1366/0003702963905295.

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A liquid suspension consisting of a mixture of H2O, D2O, and polystyrene latex microspheres was used to study the effects of multiple scattering on the near-infrared (800–1600 nm) spectrum of a pure absorber (H2O) in a turbid medium. This simple experimental model enabled us to isolate and explain the spectral distortions introduced by variations in the optical pathlength of scattered photons. We observe the following: (1) Reflectance spectra measured with the detector positioned close to and far from the point of illumination have distinctly different sensitivities to background scattering variations. Within a certain range of detector positions, the use of spectral derivatives to correct for multiplicative scattering effects is most effective. (2) The wavelength dependence of the scattering background of the log(1/ R) spectrum depends not only on particle size but also on the separation between the source and detector probes. And (3) the ratio of the magnitudes of the spectral peaks caused by absorption within the background medium and absorption within the scattering particles decreases as multiple scattering increases. We explain these observations in the context of photon-diffusion theory and point out their significance with respect to the design of diffuse-reflectance spectrometers. Photon diffusion theory proves to be valuable for interpretation of diffuse spectra, but it fails to account for spectral distortions introduced by low-order backscattering at close source–detector separations.

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7

Avdic, Senada, Roumiana Chakarova, and Imre Pazsit. "Analysis of the experimental positron lifetime spectra by neural networks." Nuclear Technology and Radiation Protection 18, no. 1 (2003): 16–21. http://dx.doi.org/10.2298/ntrp0301016a.

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This paper deals with the analysis of experimental positron lifetime spectra in polymer materials by using various algorithms of neural networks. A method based on the use of artificial neural networks for unfolding the mean lifetime and intensity of the spectral components of simulated positron lifetime spectra was previously suggested and tested on simulated data [Pzzsitetal, Applied Surface Science, 149 (1998), 97]. In this work, the applicability of the method to the analysis of experimental positron spectra has been verified in the case of spectra from polymer materials with three components. It has been demonstrated that the backpropagation neural network can determine the spectral parameters with a high accuracy and perform the decomposi-tion of lifetimes which differ by 10% or more. The backpropagation network has not been suitable for the identification of both the parameters and the number of spectral components. Therefore, a separate artificial neural network module has been designed to solve the classification problem. Module types based on self-organizing map and learning vector quantization algorithms have been tested. The learning vector quantization algorithm was found to have better performance and reliability. A complete artificial neural network analysis tool of positron lifetime spectra has been constructed to include a spectra classification module and parameter evaluation modules for spectra with a different number of components. In this way, both flexibility and high resolution can be achieved.

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8

Shi, Chenjun, Ji Zhu, Mingqian Xu, Xu Wu, and Yan Peng. "An Approach of Spectra Standardization and Qualitative Identification for Biomedical Materials Based on Terahertz Spectroscopy." Scientific Programming 2020 (October 21, 2020): 1–8. http://dx.doi.org/10.1155/2020/8841565.

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Terahertz time-domain spectroscopy (THz-TDS) systems are widely used to obtain fingerprint spectra of many different biomedical substances, and thus the identification of different biological materials, medicines, or dangerous chemicals can be realized. However, the spectral data for the same substance obtained from different THz-TDS systems may have distinct differences because of differences in system errors and data processing methods, which leads to misclassification and errors in identification. To realize the exact and fast identification of substances, spectral standardization is the key issue. In this paper, we present detailed disposal methods and execution processes for the spectral standardization and substance identification, including feature extracting, database searching, and fingerprint spectrum matching of unknown substances. Here, we take twelve biomedical compounds including different biological materials, medicines, or dangerous chemicals as examples. These compounds were analyzed by two different THz-TDS systems, one of which is a commercial product and the other is our verification platform. The original spectra from two systems showed obvious differences in their curve shapes and amplitudes. After wavelet transform, cubic spline interpolation, and support vector machine (SVM) classification with an appropriate kernel function, the spectra from two systems can be standardized, and the recognition rate of qualitative identification can be up to 99.17%.

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9

Гирсова, М. А., Т. В. Антропова, Г. Ф. Головина, И. Н. Анфимова та Л. Н. Куриленко. "Влияние химического состава пористой матрицы и атмосферы спекания на люминесцентные свойства висмутсодержащих композиционных материалов". Оптика и спектроскопия 131, № 1 (2023): 84. http://dx.doi.org/10.21883/os.2023.01.54542.4040-22.

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The spectral-optical and luminescence properties of bismuth-containing composite materials based on matrices of high-silica porous glasses are investigated. Luminescence spectra, luminescence excitation spectra, infrared transmission spectra (8000–4000 cm-1) depending on the composition of different types of matrices and sintering atmosphere (nitrogen, argon) of bismuth-containing composite materials were examined. It was found that the samples of bismuth-containing composite materials are characterized by UV (λem = 350 nm), blue-green (λem = 410–550 nm) and orange-red (λem = 600–725 nm) luminescence due to the presence of various bismuth active centers. The analysis of the spectra obtained by near-infrared spectroscopy demonstrates the formation of Bi2+ dimers of bismuth and bismuth active centers associated with silicon.

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10

Yamamoto, T., H. Matsuoka, and K. Hisano. "Raman spectra of some ferroelectric materials." Ferroelectrics 96, no. 1 (August 1989): 245–49. http://dx.doi.org/10.1080/00150198908216780.

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11

Strazzulla, G., P. Massimino, F. Spinella, L. Calcagno, and A. M. Foti. "IR spectra of irradiated organic materials." Infrared Physics 28, no. 3 (May 1988): 183–88. http://dx.doi.org/10.1016/0020-0891(88)90008-5.

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12

Anubham, S. K., R. Junjuri, A. K. Myakalwar, and M. K. Gundawar. "An Approach to Reduce the Sample Consumption for LIBS based Identification of Explosive Materials." Defence Science Journal 67, no. 3 (April 25, 2017): 254. http://dx.doi.org/10.14429/dsj.67.10690.

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<p>An experimental design based on spectral construction, which has potential to minimise the sample consumption, the number of laser shots and time required to collect the data from laser induced breakdown spectroscopy for identification of the explosive materials is reported in the study. This approach is an ideal solution in the field of hazardous material detection, where the availability of the sample can be a serious limiting factor. The experimental data recorded on a set of five high energy materials has been considered to test the performance of the proposed methodology. Multiple spectra are constructed by assuming a normal distribution at each wavelength of the spectrum, where random numbers are generated using the mean and standard deviations obtained from arbitrarily chosen five experimental spectra from each class. The newly generated spectra are called as synthetic spectra. The correct classification obtained from – K - nearest neighbour combined with principal component analysis and partial least square – discriminant analysis demonstrated very promising results. The correct classification rates differed by only<br />4 per cent - 7 per cent as compared to conventional approach where experimental spectra alone are considered for the analysis. Further, when RDX is excluded, the obtained results are almost identical with conventional approach.</p>

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13

Peng, Qixian, Shaolou Hu, and Jingyou Tang. "Spectral analytical system for measuring time-resolved spectra of materials under shock." Review of Scientific Instruments 74, no. 8 (August 2003): 3709–11. http://dx.doi.org/10.1063/1.1588748.

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14

Wallace, S., S. G. Lambrakos, and L. Massa. "Density function theory (DFT) calculated infrared absorption spectra for nitrosamines." Water Science and Technology 80, no. 10 (November 15, 2019): 1967–74. http://dx.doi.org/10.2166/wst.2020.018.

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Abstract Absorption spectra within the infrared (IR) range of frequencies for nitrosamines in water are calculated using density function theory (DFT). Calculated in this study, are the IR spectra of C2H6N2O, C4H10N2O, C6H14N2O, C4H8N2O, C3H8N2O, and C8H18N2O. DFT calculated absorption spectra corresponding to vibration excited states of these molecules in continuous water background can be correlated with additional information obtained from laboratory measurements. The DFT software Gaussian was used for the calculations of excited states presented here. This case study provides proof of concept, viz., that such DFT calculated spectra can be used for their practical detection in environmental samples. Thus, DFT calculated spectra may be used to construct templates, for spectral-feature comparison, and thus detection of spectral-signature features associated with target materials.

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15

Zhou, Qian, Zhiyong Zou, and Lin Han. "Deep Learning-Based Spectrum Reconstruction Method for Raman Spectroscopy." Coatings 12, no. 8 (August 22, 2022): 1229. http://dx.doi.org/10.3390/coatings12081229.

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Raman spectroscopy, measured by a Raman spectrometer, is usually disturbed by the instrument response function and noise, which leads to certain measurement error and further affects the accuracy of substance identification. In this paper, we propose a spectral reconstruction method which combines the existing maximum a posteriori (MAP) method and deep learning (DL) to recover the degraded Raman spectrum. The proposed method first employs the MAP method to reconstruct the measured Raman spectra, so as to obtain preliminary estimated Raman spectra. Then, a convolutional neural network (CNN) is trained by using the preliminary estimated Raman spectra and the real Raman spectra to learn the mapping from the preliminary estimated Raman spectra to the real Raman spectra, so as to achieve a better spectral reconstruction effect than merely using the MAP method or a CNN. To prove the effectiveness of the proposed spectral reconstruction method, we employed the proposed method and some traditional spectral reconstruction methods to reconstruct the simulated and measured Raman spectra, respectively. The experimental results show that compared with traditional methods, the estimated Raman spectra reconstructed by the proposed method are closer to the real Raman spectra.

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16

Zhong, W. X., C. H. Fang, S. T. Lin, S. K. Liu, C. X. Yu, J. Liang, H. T. He, et al. "Identification of neutron sources and background levels in the polyethylene room of the China Jinping Underground Laboratory." Journal of Instrumentation 16, no. 12 (December 1, 2021): P12003. http://dx.doi.org/10.1088/1748-0221/16/12/p12003.

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Abstract The neutron backgrounds induced by supplementary experimental materials can result in contaminations in rare event search experiments. To address this, we present the neutron background levels arising from ambient materials in the polyethylene room of the China Jinping Underground Laboratory; particularly, we compare simulated spectra with measured neutron spectra unfolded using a genetic algorithm. The genetic algorithm optimizes the continuity of the energy spectra and obtains a reasonable spectral result. A good agreement between the unfolded and simulated spectra is achieved. Moreover, estimated neutron background levels of representative ambient materials such as polyethylene, aluminum, and lead are obtained using an exposure time of 511.27 days via a 28 liter 0.5%-gadolinium-doped liquid scintillator detector. The identification of rare neutron sources can aid in background reduction in next-generation large-scale rare event experiments.

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17

Le Bris, A., N. Chehata, X. Briottet, and N. Paparoditis. "SPECTRAL BAND SELECTION FOR URBAN MATERIAL CLASSIFICATION USING HYPERSPECTRAL LIBRARIES." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences III-7 (June 7, 2016): 33–40. http://dx.doi.org/10.5194/isprsannals-iii-7-33-2016.

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In urban areas, information concerning very high resolution land cover and especially material maps are necessary for several city modelling or monitoring applications. That is to say, knowledge concerning the roofing materials or the different kinds of ground areas is required. Airborne remote sensing techniques appear to be convenient for providing such information at a large scale. However, results obtained using most traditional processing methods based on usual red-green-blue-near infrared multispectral images remain limited for such applications. A possible way to improve classification results is to enhance the imagery spectral resolution using superspectral or hyperspectral sensors. In this study, it is intended to design a superspectral sensor dedicated to urban materials classification and this work particularly focused on the selection of the optimal spectral band subsets for such sensor. First, reflectance spectral signatures of urban materials were collected from 7 spectral libraires. Then, spectral optimization was performed using this data set. The band selection workflow included two steps, optimising first the number of spectral bands using an incremental method and then examining several possible optimised band subsets using a stochastic algorithm. The same wrapper relevance criterion relying on a confidence measure of Random Forests classifier was used at both steps. To cope with the limited number of available spectra for several classes, additional synthetic spectra were generated from the collection of reference spectra: intra-class variability was simulated by multiplying reference spectra by a random coefficient. At the end, selected band subsets were evaluated considering the classification quality reached using a rbf svm classifier. It was confirmed that a limited band subset was sufficient to classify common urban materials. The important contribution of bands from the Short Wave Infra-Red (SWIR) spectral domain (1000–2400 nm) to material classification was also shown.

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18

Le Bris, A., N. Chehata, X. Briottet, and N. Paparoditis. "SPECTRAL BAND SELECTION FOR URBAN MATERIAL CLASSIFICATION USING HYPERSPECTRAL LIBRARIES." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences III-7 (June 7, 2016): 33–40. http://dx.doi.org/10.5194/isprs-annals-iii-7-33-2016.

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In urban areas, information concerning very high resolution land cover and especially material maps are necessary for several city modelling or monitoring applications. That is to say, knowledge concerning the roofing materials or the different kinds of ground areas is required. Airborne remote sensing techniques appear to be convenient for providing such information at a large scale. However, results obtained using most traditional processing methods based on usual red-green-blue-near infrared multispectral images remain limited for such applications. A possible way to improve classification results is to enhance the imagery spectral resolution using superspectral or hyperspectral sensors. In this study, it is intended to design a superspectral sensor dedicated to urban materials classification and this work particularly focused on the selection of the optimal spectral band subsets for such sensor. First, reflectance spectral signatures of urban materials were collected from 7 spectral libraires. Then, spectral optimization was performed using this data set. The band selection workflow included two steps, optimising first the number of spectral bands using an incremental method and then examining several possible optimised band subsets using a stochastic algorithm. The same wrapper relevance criterion relying on a confidence measure of Random Forests classifier was used at both steps. To cope with the limited number of available spectra for several classes, additional synthetic spectra were generated from the collection of reference spectra: intra-class variability was simulated by multiplying reference spectra by a random coefficient. At the end, selected band subsets were evaluated considering the classification quality reached using a rbf svm classifier. It was confirmed that a limited band subset was sufficient to classify common urban materials. The important contribution of bands from the Short Wave Infra-Red (SWIR) spectral domain (1000–2400 nm) to material classification was also shown.

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19

Hofstraat, J. W., and M. J. Latuhihin. "Correction of Fluorescence Spectra." Applied Spectroscopy 48, no. 4 (April 1994): 436–47. http://dx.doi.org/10.1366/000370294775269027.

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Several methods that can be applied to remove wavelength-dependent instrumental effects from fluorescence emission and excitation spectra have been investigated. Removal of such artifacts is necessary for the comparison of spectra that have been obtained on different instruments. Without correction, spectral line positions and relative intensities will be instrument-determined to a great extent. Furthermore, the application of adequate correction procedures provides excitation spectra which can be directly compared to absorption spectra; comparison of corrected excitation spectra and absorption spectra can be used to interpret the efficiency and pathways of radiative processes. Finally, corrected reflection spectra can be obtained, which can be directly transformed into absorption spectra and are useful for remote sensing applications. The methods that have been studied for the correction of emission spectra are the application of a standard lamp with calibrated spectral output and the use of fluorescence standards. The standards are a series of luminescent phosphors in polymer films and a solution of quinine sulfate dihydrate in perchloric acid, all provided with certified spectral emission values. For correction of excitation spectra, a quantum counter was applied. Several quantum counters were investigated. The best results were obtained for application of a mixture of the dyes basic blue and HITC, which provided good correction for the wavelength range 250 to 820 nm. No good quantum counters have been reported thus far for this (large) wavelength range. Correction for wavelength dependence of the excitation optics was realized by measurement of the excitation light intensity at the sample position and at the reference position with a Si photodiode. Correction factors for the excitation spectra were checked with a number of reference materials. Attention has also been paid to polarization-dependent effects that may occur in fluorescence spectra. The application of correction procedures was demonstrated for phytoplankton fluorescence spectra.

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20

Gąsiorowski, Marek, Piotr Szymak, Aleksy Patryn, and Krzysztof Naus. "Monitoring Time-Non-Stable Surfaces Using Mobile NIR DLP Spectroscopy." Electronics 11, no. 13 (June 22, 2022): 1945. http://dx.doi.org/10.3390/electronics11131945.

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In recent years, Near Infrared (NIR) spectroscopy has increased in popularity and usage for different purposes, including the detection of particular substances, evaluation of food quality, etc. Usually, mobile handheld NIR spectroscopy devices are used on the surfaces of different materials, very often organic ones. The features of these materials change as they age, leading to changes in their spectra. The ageing process often occurs only slowly, i.e., corresponding reflection spectra can be analyzed each hour or at an even longer interval. This paper undertakes the problem of analyzing surfaces of non-stable, rapidly changing materials such as waxes or adhesive materials. To obtain their characteristic spectra, NIR spectroscopy using a Digital Light Projection (DLP) spectrometer was used. Based on earlier experiences and the current state of the art, Artificial Neural Networks (ANNs) were used to process spectral sequences to proceed with an enormous value of spectra gathered during measurements.

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21

Wooden, Diane H. "Cometary Silicates: Interstellar and Nebular Materials." Highlights of Astronomy 13 (2005): 495–97. http://dx.doi.org/10.1017/s1539299600016403.

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AbstractEvidence for interstellar material in comets is deduced from IR spectra, in situ measurements of Comet Halley, and chondritic porous interplanetary dust particles (CP IDPs). IR spectra of comets reveal the spectrally active minerals: amorphous carbon, amorphous silicates, and (in some comets) crystalline silicates. Evidence suggests amorphous silicates are of interstellar origin while crystalline silicates are of nebular origin.10 μm spectra of comets and sub-micron amorphous silicate spherules in CP IDPs have shapes similar to absorption spectra through lines-of-sight in the ISM. Thermal emission models of cometary IR spectra require Fe-bearing amorphous silicates. Fe-bearing amorphous silicates may be Fe-bearing crystalline silicates formed in AGB outflows that are amorphized through He+ ion bombardment in supernova shocks in the ISM.Crystalline silicates in comets, as revealed by IR spectra, and their apparent absence in the ISM, argues for their nebular origin. The high temperatures (>1000 K) at which crystals form or are annealed occur in the inner nebula or in nebular shocks in the 5 – 10 AU region. Oxygen isotope studies of CP IDPs show only 1% by mass of the silicate crystals are of AGB origin. Together this suggests crystalline silicates in comets are probably primitive grains from the early solar nebula.

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22

Xie, Yingfang, Jinglin You, Liming Lu, Min Wang, and Jian Wang. "Raman Spectroscopic Study of Coal Samples during Heating." Applied Sciences 9, no. 21 (November 4, 2019): 4699. http://dx.doi.org/10.3390/app9214699.

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Raman spectroscopy can be used to record the characteristic spectra of carbonaceous materials. The D and G bands are the most popular and most important spectral characteristics when discussing carbonaceous materials. In this paper, a Raman spectroscopic study of different coals was first carried out using a 355 nm wavelength laser beam as an excitation source. The spectral parameters of the resultant spectra were evaluated and analyzed. Raman spectral characteristics of different kinds of coals were explored. The high temperature-dependent Raman spectra of the coals were further collected in a temperature range from 298 to 1473 K in order to investigate the transformations of the internal structure of the coals during the pyrolysis process. An abnormal blue shift of the G band occurred at moderate temperature (600–900 K), and the intensity of the G band became weaker at high temperatures, indicating pyrolysis and graphitization of the sample at moderate and high temperature, respectively.

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23

Proschenko, Dmitriy, Sergey Golik, Alexey Chekhlenok, Irina Postnova, Yuri Shchipunov, and Yuri N. Kulchin. "Nonlinear Optical Properties of Biosilicate Nanocomposite Materials." Advanced Materials Research 677 (March 2013): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amr.677.3.

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The transmission of the femtosecond laser pulses by new biosilicate nanocomposite materials has been experimentally investigated. The strong nonlinear optical properties of these nanocomposite structures have been revealed in spectral characteristics of transmitted ultrashort pulses. The shape of transmitted spectrums through new nanocomposite biomaterials demonstrates major changes indicating the broadening with formation a strong anti Stokes component in the output spectrum with generation of supercontinuum spectra. The carried out studies have showed that the optical nonlinearity of new nanocomposite materials can be regulated by trace amounts of Au or CdS nanoparticles.

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Amarie, Sergiu, Paul Zaslansky, Yusuke Kajihara, Erika Griesshaber, Wolfgang W. Schmahl, and Fritz Keilmann. "Nano-FTIR chemical mapping of minerals in biological materials." Beilstein Journal of Nanotechnology 3 (April 5, 2012): 312–23. http://dx.doi.org/10.3762/bjnano.3.35.

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Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies.

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25

Yamanoi, Yuta, and Satoru Nakashima. "In situ High-Temperature Visible Microspectroscopy for Volcanic Materials." Applied Spectroscopy 59, no. 11 (November 2005): 1415–19. http://dx.doi.org/10.1366/000370205774783205.

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In situ high-temperature visible microspectroscopy has been developed in order to study color change kinetics of volcanic materials. Olivine thin sections put on a synthetic alumina plate are heated on a heating stage at 600–800 °C under a visible microspectroscope. Changes in visible absorption spectra are monitored every 60 s for 5 hours. The obtained high-temperature visible spectra showed a gradual increase with time in absorbance in the shorter wavelength region (400–600 nm). The 430 nm absorbance (ligand field transition of Fe3+) increased more with time at higher temperatures. Assuming diffusional transport in plane sheets, apparent diffusion coefficients were determined at temperatures of 600–800 °C. The activation energy for this diffusion in olivine is 208 ± 17 kJ/mol. This activation energy value is similar to those for the metal vacancy diffusion in olivine. This newly developed in situ high-temperature visible microspectroscopy can provide kinetic measurements of visible spectral change of materials at high temperatures such as volcanic materials.

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26

Reeves, James B. "Spectral Effects of Water in the 10,000 to 8000 cm−1 (1000 to 1250 nm) near Infrared Spectral Region. And, Can They Explain Previously Seen Effects of Water in the Spectral Region from 14,000 to 11,500 cm−1 (714 to 870 nm)?" Journal of Near Infrared Spectroscopy 3, no. 3 (June 1995): 143–53. http://dx.doi.org/10.1255/jnirs.65.

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The spectral region from 10,000 to 8000 cm−1 (1000 to 1250 nm) is often used for high moisture samples and fibre optic systems. The first objective of this work was to determine the effects of water on the spectra of various types of materials in this spectral region. The second objective was to determine the origin/nature of spectral effects/artifacts seen in the spectral region from 14,000 to 11,500 cm−1 (714 to 870 nm) when water was added to gums and proteins (increases in peak intensities and shifts in position due to the presence of water). Spectra were obtained by diffuse reflectance and transmission using a Fourier transform spectrometer. The results showed that the effects seen in the mid-infrared and near infrared from 8000 to 4000 cm−1 (1250 to 2500 nm) were also common in this part of the near infrared (i.e. peak shifts, loss of spectral features etc). Thus, the spectra of crystalline glucose and sucrose, while distinctively different as crystalline solids, were very similar when in solution and changes in the spectra of materials, such as acetone, pyridine and ethanol, were very similar in nature to those previously found in the near infrared from 8000 to 4000 cm−1 (1250 to 2500 nm). Finally, detailed examination of spectra in the region from 10,000 to 8000 or 6000 cm−1 (1000 to 1250 or 1667 nm) did not show any spectral effects similar to those seen in gums and proteins in the 14,000 to 11,500 cm−1 (714 to 870 nm) region. Thus, the nature of these effects is still unknown.

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27

Tatsumi, Kazuyoshi, Yu Yamamoto, and Shunsuke Muto. "Site-by-Site Electronic Structure Analysis of Al-Containing Complex Compounds Using Channeling EELS and First Principles Calculations." Materials Science Forum 561-565 (October 2007): 2091–94. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2091.

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Al K ELNES of oxide ceramics, which show reverse spinel and garnet structures containing two types of Al sites, are investigated site-selectively using TEM-EELS under electron channeling conditions. We applied a self-modeling curve resolution (SMCR) technique to separate a set of experimental spectra into individual spectra of individual atomic sites. The refined spectra after SMCR were in consistent with the theoretical spectra obtained by the first principles electronic structure calculations. The spectral difference of the six-coordinated aluminum between the two materials was discussed in terms of the cationic coordination.

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28

Rodriguez, Mark A., Mark H. Van Benthem, Donald F. Susan, James J. M. Griego, Pin Yang, Curtis D. Mowry, and David G. Enos. "Materials assurance through orthogonal materials measurements: X-ray fluorescence aspects." Powder Diffraction 32, no. 2 (June 2017): 124–32. http://dx.doi.org/10.1017/s0885715617000446.

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X-ray fluorescence (XRF) has been employed as one of several orthogonal means of screening materials to prevent counterfeit and adulterated products from entering the product stream. We document the use of principal component analysis (PCA) of XRF data on compositionally similar and dissimilar stainless steels for the purpose of testing the feasibility of employing XRF spectra to parse and bin these alloys as the same or significantly different alloy materials. The results indicate that XRF spectra can separate and assign alloys via PCA, but that important corrections for detector drift and scaling must be performed in order to achieve valid results.

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29

Lapshinov, B. A., and N. I. Timchenko. "Determination of the profile of the temperature field of material heated by continuous laser radiation." Physics and Chemistry of Materials Treatment, no. 3 (2020): 51–10. http://dx.doi.org/10.30791/0015-3214-2020-3-5-10.

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Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.

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30

Han, Tao, Hongxia Liu, Shulong Wang, Shupeng Chen, Kun Yang, and Zhandong Li. "Synthesis and Spectral Characteristics Investigation of the 2D-2D vdWs Heterostructure Materials." International Journal of Molecular Sciences 22, no. 3 (January 27, 2021): 1246. http://dx.doi.org/10.3390/ijms22031246.

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Due to the attractive optical and electrical properties, van der Waals (vdWs) heterostructures constructed from the different two-dimensional materials have received widespread attention. Here, MoS2/h-BN, MoS2/graphene, WS2/h-BN, and WS2/graphene vdWs heterostructures are successfully prepared by the CVD and wet transfer methods. The distribution, Raman and photoluminescence (PL) spectra of the above prepared heterostructure samples can be respectively observed and tested by optical microscopy and Raman spectrometry, which can be used to study their growth mechanisms and optical properties. Meanwhile, the uniformity and composition distribution of heterostructure films can also be analyzed by the Raman and PL spectra. The internal mechanism of Raman and PL spectral changes can be explained by comparing and analyzing the PL and Raman spectra of the junction and non-junction regions between 2D-2D vdWs heterostructure materials, and the effect of laser power on the optical properties of heterostructure materials can also be analyzed. These heterostructure materials exhibit novel and unique optical characteristics at the stacking or junction, which can provide a reliable experimental basis for the preparation of suitable TMDs heterostructure materials with excellent performance.

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31

Basavaraja, Thippeswamy, Somashekara Bhadrachar, and Kittappa M. Mahadevan. "Transition Metal Complexes of Pyridyl Ligand as Light Emitting Materials in OLEDs." Asian Journal of Chemistry 32, no. 1 (November 18, 2019): 161–66. http://dx.doi.org/10.14233/ajchem.2020.22371.

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Transition metal complexes, viz., tetrapyridylbis(isothiocyanato)nickel(II) (1), dipyridylbis (isothiocyanato)copper(II) (2) and dipyridylbis-(isothiocyanato)zinc(II) (3) were synthesized by conventional methods. All the synthesized metal complexes were characterized by spectral and elemental analysis. Diffused reflectance (DR) spectra of the complexes 1-3 recorded in the range 200-1100 nm exhibit major peaks at 450 nm and 750 nm (% diffused reflectance 50 and 55, respectively) for complex 1, 500 nm (20 % diffused reflectance) for complex 2 and 400 nm (50 % diffused reflectance) for complex 3. The excitation and emission peaks obtained from photoluminescence spectra indicated the emission of white, green and white lights by the complexes 1, 2 and 3, respectively. From diffused reflectance spectra, the measured band gap energies were found to be 3.95 eV for complex 1, 2.77 eV for complex 2 and 4.3 eV for complex 3. Commission Internationale de l'Eclairage (CIE) coordinates of (0.31533, 0.33082), (0.22605, 0.35099) and (0.28633, 0.31012) were calculated for the complexes 1, 2 and 3, respectively. The phosphors 1-3 were readily soluble in various common organic solvents and they could become promising light emitting materials in organic light emitting diodes (OLEDs).

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32

Ivakha, Nadiia, Oleksandra Berezhnytska, Elena Trunova, and Oleksandr Rohovtsov. "SYNTHESIS AND RESEARCH OF LANTHANIDE-CONTAINING HYBRID MATERIALS BASED ON POLYHEDRAL OLIGOMERIC SILSESQUIOXANES." Ukrainian Chemistry Journal 86, no. 6 (July 20, 2020): 74–86. http://dx.doi.org/10.33609/2708-129x.86.6.2020.74-86.

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New hybrid materials were synthesized based on meteacroacetophenate neodymium (III) and erbium (III) and polyhedral oligomeric sissesquioxane POSS formula C24H72Cl8N8O12Si8. A warehouse has been put in place for a new synthesis. In the IR spectra of the synthesized hybrid materials in the range of 400–650 cm–1 there are oscillation bands that correspond to the valence oscillations of the bonds (Ln-O) and (Ln-N) and the deformation oscillations of the chelate ring. The decrease in intensity compared to the spectra of Ln(mphpd)3 complexes is due to the appearance of valence oscillations of the Ln-N bond and steric difficulties that arise when the complex coordinates to the sizable siloxane molecule. An additional intense broad band appears in the IR spectra, which is characterized by fluctuations in the valence of the Si-O-Si siloxane bond with a maximum of 1050 cm-1. The presence of a wide absorption band in the range of 1500–1700 cm-1, characterized by valence oscillations of ν (CO) and ν (CC), confirms the bidentate-cyclic coordination of β-diketonates. Thus, the shape and position of the bands in the IR spectra indicate the formation of a hybrid structure of the composition POSS- [Ln (mphpd)3]4. The shape, position, displacement and splitting of the spectral bands in the electronic spectra and diffuse reflectance spectra indicate the passage of the processes of complexation and the formation of complexes of non-cubic symmetry with coordination number 8. Thus, the presence of insignificant displacements of the absorption bands indicates the invariance of the coordination environment and the geometry of the coordination polyhedron for metal complexes and hydride systems based on them. The shift of the bands of supersensitive transitions in comparison with the spectra of metal complexes indicates both additional coordination of nitrogen atoms of the silsesquioxane molecule and some deformation of the coordination polyhedron, which is due to steric difficulties. According to the set of data from thermal and spectroscopic studies, the structure of the obtained hybrid material can be represented as follows. The results of EDX analysis, the method of dynamic light scattering and microphotographs are consistent and indicate the nanodispersity of the obtained systems.

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33

Morgan, David J. "Comments on the XPS Analysis of Carbon Materials." C 7, no. 3 (July 6, 2021): 51. http://dx.doi.org/10.3390/c7030051.

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The surface chemistry of carbon materials is predominantly explored using x-ray photoelectron spectroscopy (XPS). However, many published papers have critical failures in the published analysis, stemming from an ill-informed approach to analyzing the spectroscopic data. Herein, a discussion on lineshapes and changes in the spectral envelope of predominantly graphitic materials are explored, together with the use of the D-parameter, to ascertain graphitic content, using this information to highlight a simple and logical approach to strengthen confidence in the functionalization derived from the carbon core-level spectra.

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34

Мамелин, Ю. В., Г. Ф. Копытов та В. Ю. Бузько. "Дискриминация хвойных и лиственных листьев деревьев и кустарников от декоративно-искусственных материалов методом оптической спектроскопии диффузного отражения света". Журнал технической физики 128, № 2 (2020): 290. http://dx.doi.org/10.21883/os.2020.02.48981.288-19.

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The article was the first time investigation the spectra of diffuse light reflection from coniferous and deciduous green leaves of trees and shrubs that growing in the Krasnodar region territory. The obtained spectral data were compared with the spectra of diffuse light reflection from green synthetic decorative and artificial leaves and various camouflage materials. The use of vegetation indices of "greenness" to discriminate coniferous and deciduous leaves of trees and shrubs from decorative and artificial materials by optical diffuse reflectance spectroscopy was proposed.

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35

RYCHETSKY, I., and J. PETZELT. "Dielectric Spectra of Grainy High-Permittivity Materials." Ferroelectrics 303, no. 1 (January 2004): 137–40. http://dx.doi.org/10.1080/00150190490453072.

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36

Vilaithong, T., S. Wanwilairat, M. Rhodes, W. Hoffmann, and T. Messarius. "High Resolution Emission Spectra of TL Materials." Radiation Protection Dosimetry 100, no. 1 (July 1, 2002): 211–15. http://dx.doi.org/10.1093/oxfordjournals.rpd.a005849.

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37

Grimes, Craig A., and Dale M. Grimes. "Permeability and permittivity spectra of granular materials." Physical Review B 43, no. 13 (May 1, 1991): 10780–88. http://dx.doi.org/10.1103/physrevb.43.10780.

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38

Kasagi, Teruhiro, Takanori Tsutaoka, and Kenichi Hatakeyama. "Complex permeability spectra of permendur composite materials." Journal of Physics: Conference Series 200, no. 8 (January 1, 2010): 082012. http://dx.doi.org/10.1088/1742-6596/200/8/082012.

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39

Lomovskoi, V. A., N. Yu Lomovskaya, A. G. Barteneva, and N. A. Abaturova. "Internal friction spectra of cryptoheterogeneous polymer materials." Doklady Physical Chemistry 415, no. 1 (July 2007): 195–98. http://dx.doi.org/10.1134/s0012501607070081.

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40

Galiyarova, Nina M., Stanislav V. Gorin, and Lidiya I. Dontsova. "Fractality and dielectric spectra of ferroic materials." Materials Research Innovations 3, no. 1 (June 1999): 30–41. http://dx.doi.org/10.1007/s100190050122.

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41

Rodil, S. E. "Infrared spectra of amorphous carbon based materials." Diamond and Related Materials 14, no. 8 (August 2005): 1262–69. http://dx.doi.org/10.1016/j.diamond.2005.01.044.

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42

Kurmaev, E. Z., S. N. Shamin, K. M. Kolobova, and S. V. Shulepov. "X-ray emission spectra of carbon materials." Carbon 24, no. 3 (1986): 249–53. http://dx.doi.org/10.1016/0008-6223(86)90224-1.

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43

Koirala, Bikram, Mahdi Khodadadzadeh, Cecilia Contreras, Zohreh Zahiri, Richard Gloaguen, and Paul Scheunders. "A Supervised Method for Nonlinear Hyperspectral Unmixing." Remote Sensing 11, no. 20 (October 22, 2019): 2458. http://dx.doi.org/10.3390/rs11202458.

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Due to the complex interaction of light with the Earth’s surface, reflectance spectra can be described as highly nonlinear mixtures of the reflectances of the material constituents occurring in a given resolution cell of hyperspectral data. Our aim is to estimate the fractional abundance maps of the materials from the nonlinear hyperspectral data. The main disadvantage of using nonlinear mixing models is that the model parameters are not properly interpretable in terms of fractional abundances. Moreover, not all spectra of a hyperspectral dataset necessarily follow the same particular mixing model. In this work, we present a supervised method for nonlinear spectral unmixing. The method learns a mapping from a true hyperspectral dataset to corresponding linear spectra, composed of the same fractional abundances. A simple linear unmixing then reveals the fractional abundances. To learn this mapping, ground truth information is required, in the form of actual spectra and corresponding fractional abundances, along with spectra of the pure materials, obtained from a spectral library or available in the dataset. Three methods are presented for learning nonlinear mapping, based on Gaussian processes, kernel ridge regression, and feedforward neural networks. Experimental results conducted on an artificial dataset, a data set obtained by ray tracing, and a drill core hyperspectral dataset shows that this novel methodology is very promising.

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44

Reeves, James B. "Near- versus Mid-Infrared Spectroscopy: Relationships between Spectral Changes Induced by Water and Relative Information Content of the Two Spectral Regions in Regard to High-Moisture Samples." Applied Spectroscopy 49, no. 3 (March 1995): 295–303. http://dx.doi.org/10.1366/0003702953963544.

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The objectives of this work were to examine similarities and differences in the near-infrared and mid-infrared spectral regions when one is working with high-moisture materials and to study spectral changes in these regions as a method to identify the relationship of spectral information in the near-IR to fundamental absorptions in the mid-IR. Near- and mid-infrared spectra were taken with a Digilab FTS-65 Fourier transform spectrometer. Liquids were examined by transmission and solids by reflectance. Results with solutions showed that less spectral distortion arises when one is subtracting water from mid- rather than from near-infrared spectra. It was also easier to produce high-quality spectra in the mid-infrared by using attenuated total reflectance than by using transmission in the near-infrared. While mid-infrared spectra showed changes (induced by water, pH, physical state, and ionic strength) similar to those found in the near-infrared, there appeared to be more information available in the mid-infrared, even in the presence of water.

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45

Reeves, James B. "Influence of pH, Ionic Strength, and Physical State on the Near-Infrared Spectra of Model Compounds." Journal of AOAC INTERNATIONAL 77, no. 4 (July 1, 1994): 814–20. http://dx.doi.org/10.1093/jaoac/77.4.814.

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Abstract The accuracy of near-infrared spectroscopy (NIRS) when applied to high-moisture samples (i.e., silages) does not match that with dried materials. Previous work showed that the presence of water could cause shifts in the spectra of organic compounds, the degree of which depended on the material and the water concentration. For some solids, such as sugars, large spectral changes occur on dissolution. The objective of this study was to determine the effect of pH, ionic strength, and physical state on the NIR spectra of model compounds. The results show that pH has large effects on the spectra of amines and acids but little if any on the spectra of ketones, alcohols, and sugars. The spectra of peptides and proteins also were pH dependent, but that of cellulose was not. Ionic strength differences (deionized water vs saturated NaCI solution as the diluting media) had only minor or no effect on the spectra of the materials studied. The effect of physical state was far more complicated; the spectra of freeze-dried glucose and glycine were different from that of the crystalline forms, but the spectrum of serine was not. The spectra of molten compounds often appeared like those of solutions. These results, in agreement with earlier work, may explain the poorer performance of NIRS with wet materials compared with dry samples. They also have serious implications for the analysis of dried samples, if pH, ionic strength, or drying method varies among samples.

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46

Gallhofer, Daniela, and Bernd Lottermoser. "The Influence of Spectral Interferences on Critical Element Determination with Portable X-Ray Fluorescence (pXRF)." Minerals 8, no. 8 (July 27, 2018): 320. http://dx.doi.org/10.3390/min8080320.

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Field portable X-ray fluorescence (pXRF) spectrometers are routinely used in mineral resources studies. To date, mineral resources studies have largely focussed on the application of pXRF to the exploration for deposits of base and precious metals. By contrast, studies using pXRF for the quantification of critical elements in geological materials are scarce since these elements are difficult to determine with energy-dispersive pXRF technology. This study explores the capability of pXRF spectrometers to detect and quantify critical elements (Ba, P, Nb, V, Co, REE, W, Bi, Hf, and Ta) in certified reference materials (CRMs). While precision of many critical elements is acceptable (<20% RSD), accuracy can be poor (>50% difference) when using pre-installed factory calibration software. Spectra collected during the pXRF measurements show that poor accuracy and false positives tend to be associated with spectral interferences. Distinct combinations of spectral interferences (line overlaps, Compton scattered peaks, and Si escape peaks) were observed in the different matrix types. Our results show that critical elements may be determined in common geological materials when pronounced peaks occur in the spectra and that matrix-match of standards and samples is essential. Hence, XRF spectra should be routinely reviewed to identify erroneous quantification due to spectral interferences.

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47

Fedorenko, Dmitriy S., and Konstantin E. Legkov. "Modeling of the High-Orbital Satellite Reflection Spectrum." T-Comm 14, no. 11 (2020): 14–20. http://dx.doi.org/10.36724/2072-8735-2020-14-11-14-20.

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A version of the model for the formation of the reflection spectrum of a high-orbit satellite based on mixing laboratory reflection spectra of materials and coatings is presented, which allows reproducing the spectral distribution of the optical radiation stream reflected from the satellite in the visible range for further processing for the purpose of qualitative and quantitative interpretation of the reflection spectra.

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48

Ilehag, R., J. Leitloff, M. Weinmann, and A. Schenk. "URBAN MATERIAL CLASSIFICATION USING SPECTRAL AND TEXTURAL FEATURES RETRIEVED FROM AUTOENCODERS." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-1-2020 (August 3, 2020): 25–32. http://dx.doi.org/10.5194/isprs-annals-v-1-2020-25-2020.

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Abstract. Classification of urban materials using remote sensing data, in particular hyperspectral data, is common practice. Spectral libraries can be utilized to train a classifier since they provide spectral features about selected urban materials. However, urban materials can have similar spectral characteristic features due to high inter-class correlation which can lead to misclassification. Spectral libraries rarely provide imagery of their samples, which disables the possibility of classifying urban materials with additional textural information. Thus, this paper conducts material classification comparing the benefits of using close-range acquired spectral and textural features. The spectral features consist of either the original spectra, a PCA-based encoding or the compressed spectral representation of the original spectra retrieved using a deep autoencoder. The textural features are generated using a deep denoising convolutional autoencoder. The spectral and textural features are gathered from the recently published spectral library KLUM. Three classifiers are used, the two well-established Random Forest and Support Vector Machine classifiers in addition to a Histogram-based Gradient Boosting Classification Tree. The achieved overall accuracy was within the range of 70–80% with a standard deviation between 2–10% across all classification approaches. This indicates that the amount of samples still is insufficient for some of the material classes for this classification task. Nonetheless, the classification results indicate that the spectral features are more important for assigning material labels than the textural features.

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49

Mutlu, Ömer Faruk, Arzu Binici, Aytuğ Okumuş, Gamze Elmas, Bünyemin Çoşut, Zeynel Kılıç, and Tuncer Hökelek. "Phosphorus–nitrogen compounds. Part 54. syntheses of chiral amino-4-fluorobenzyl-spiro(N/O)cyclotriphosphazenes: structural and stereogenic properties." New Journal of Chemistry 45, no. 27 (2021): 12178–92. http://dx.doi.org/10.1039/d1nj00934f.

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Syntheses, spectral and crystallographic characterizations and stereogenic properties by ³¹P NMR spectra recorded with the addition of CSA, CD spectra and chiral HPLC of amino-4-fluorobenzylspiro(N/O)cyclotriphosphazenes were examined.

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50

Bingol, Kerem, Roberto K. Salinas, and Rafael Brüschweiler. "Higher-Rank Correlation NMR Spectra with Spectral Moment Filtering." Journal of Physical Chemistry Letters 1, no. 7 (March 11, 2010): 1086–89. http://dx.doi.org/10.1021/jz100264g.

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