Journal of Spectroscopy https://www.hindawi.com The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Inhibition Effect of Phosphorus Flame Retardants on the Fire Disasters Induced by Spontaneous Combustion of Coal Tue, 31 Jan 2017 09:13:53 +0000 http://www.hindawi.com/journals/jspec/2017/7635468/ Coal spontaneous combustion (CSC) generally induces fire disasters in underground mines, thus causing serious casualties, environmental pollution, and property loss around the world. By using six P-containing additives to process three typical coal samples, this study investigated the variations of the self-ignition characteristics of the coal samples before and after treatment. The analysis was performed by combining thermogravimetric analysis/differential scanning calorimetry (TG/DSC) Fourier transform infrared spectrometer (FTIR) and low temperature oxidation. Experimental results showed that P-containing inhibitors could effectively restrain the heat emitted in the combustion of coal samples and therefore the ignition temperature of the coal samples was delayed at varying degrees. The combustion rate of the coal samples was reduced as well. At the temperatures ranging from 50°C to 150°C, the activation energy of the coal samples after the treatment was found to increase, which indicated that the coal samples were more difficult to be oxidized. After being treated with phosphorus flame retardants (PFRs), the content of several active groups represented by the C-O structure in the three coal samples was proved to be obviously changed. This suggested that PFRs could significantly inhibit the content of CO generated by the low temperature oxidation of coal, and the flame-retardant efficiency grew with the increasing temperature. At 200°C, the maximal inhibition efficiency reached approximately 85%. Yibo Tang Copyright © 2017 Yibo Tang. All rights reserved. A Low-Field Temperature Dependent EPR Signal in Terraced MgO:Mn2+ Nanoparticles: An Enhanced Zeeman Splitting in the Wide-Bandgap Oxide Thu, 19 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jspec/2017/8276520/ Mn2+ ion doping is used as an electron paramagnetic resonance (EPR) probe to investigate the influence of low-coordination structural defects such as step edges at the surface of terraced (001) MgO nanoparticles on the electronic properties. Beside the well-known hyperfine sextet of Mn2+ ions in the cubic crystal field of MgO, an additional EPR feature with a striking nonmonotonous temperature dependent shift of the -factor is observed in terraced nanoparticles in the temperature range from 4 K to room temperature. By linking the difference in the temperature dependence of the Mn2+ sextet intensity in cubic and terraced nanoparticles with the possible s-d exchange shift and enhanced Zeeman splitting we conclude that the novel EPR feature originates from the loosely trapped charge-compensating carriers at the abundant structural defects at the surface of terraced nanoparticles due to their exchange interaction with neighboring Mn2+ ions. Peter V. Pikhitsa, Sukbyung Chae, Seungha Shin, and Mansoo Choi Copyright © 2017 Peter V. Pikhitsa et al. All rights reserved. Experimental Study on the Atomization and Chemiluminescence Characteristics of Ethanol Flame Thu, 19 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jspec/2017/2106376/ The breakup regime in ethanol diffusion flame under different conditions was studied by the high speed camera system combined with the UV camera system. Spray angle and Weber number (We) were used to represent the change of breakup regime. With the increases of spray angle and We, the breakup mode changes from the Rayleigh-type breakup regime to the superpulsating regime. The reaction area and intensity of ethanol flames under different breakup regimes could be discussed by the distribution. From Rayleigh-type breakup regime to superpulsating breakup regime, the distribution increased and the oxidation-reduction reaction area expanded. At the condition of superpulsating breakup mode, the intensity of was significantly higher than that of other modes. The flame luminous length can be obtained by the emission, and distribution reflects the structure of flame. When the breakup regime changes from the fiber-type breakup regime to the superpulsating regime, the flame luminous length increases suddenly. Qing Zhang, Xudong Song, Qinghua Guo, Yan Gong, Chonghe Hu, and Guangsuo Yu Copyright © 2017 Qing Zhang et al. All rights reserved. A Derivative Spectrometric Method for Hydroquinone Determination in the Presence of Kojic Acid, Glycolic Acid, and Ascorbic Acid Wed, 18 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jspec/2017/6929520/ A new, simple, and sensitive spectrometric method was developed for hydroquinone (HQ) determination in the presence of other depigmenting agents (kojic acid (KA), glycolic acid (GA), and ascorbic acid (AA)), commonly introduced in skin lightening products. The method is based on the oxidation of the depigmenting agents by potassium dichromate in sulfuric acid medium and subsequent measurement of the amplitude of the first-order derivative absorption spectrum at 268 nm. By applying the zero-crossing method, at this wavelength, the oxidation products of KA, AA, and GA do not interfere in the indirect determination of HQ. Beer’s law was obeyed in the range of 0.22–22 μg·mL−1 HQ, with a detection limit of 0.07 μg·mL−1. The developed method was applied with good results for the first time to the rapid determination of HQ in binary, ternary, and quaternary mixtures, thus proving that it could represent an effective tool for various skin lightening products analyses. Zenovia Moldovan, Dana Elena Popa, Iulia Gabriela David, Mihaela Buleandra, and Irinel Adriana Badea Copyright © 2017 Zenovia Moldovan et al. All rights reserved. Photophysical Properties of Fluorescent Probe Thioflavin T in Crowded Milieu Thu, 12 Jan 2017 07:46:28 +0000 http://www.hindawi.com/journals/jspec/2017/2365746/ Thioflavin T (ThT) is a widely used fluorescent probe of amyloid fibrils, which accompanies many serious neurodegenerative and other diseases. Until recently, examinations of processes of amyloid fibril formation in vitro were conducted in solutions whose properties were significantly different from those found inside the densely packed cells. Such crowded cellular milieu is typically simulated in vitro using concentrated solutions of inert polymers, which do not usually interact with proteins. However, these crowding agents can have a direct effect on the ThT molecule, and this effect must be taken into account. We examined the influence of PEG-400, PEG-12000, and Dextran-70 on the photophysical properties of ThT. It was shown that these crowding agents caused the red shift of the absorption, fluorescence excitation, and fluorescence spectra of ThT. Under these conditions, the increases of the molar extinction coefficient, fluorescence quantum yield, and excitation lifetime of ThT are also observed. However, these changes are significantly less pronounced than those observed for ThT bound to fibrils. It is concluded that, despite some effects of crowding agents on intrinsic fluorescent properties of ThT, this dye can be used as a probe of structure and formation of amyloid fibrils in crowded milieu in vitro. Natalia P. Rodina, Maksim I. Sulatsky, Anna I. Sulatskaya, Irina M. Kuznetsova, Vladimir N. Uversky, and Konstantin K. Turoverov Copyright © 2017 Natalia P. Rodina et al. All rights reserved. Science Applied for the Investigation of Imperial Gate from Eighteenth Century Wooden Church of Nicula Monastery Wed, 11 Jan 2017 12:12:46 +0000 http://www.hindawi.com/journals/jspec/2017/6167856/ Part of an indestructible component of any orthodox church, the Imperial Gates represent an important symbol in our cultural heritage. But in many cases the Imperial Gates from the wooden churches were damaged. In order to preserve and restore them, the scientific investigations of the Imperial Gate belonging to Nicula Monastery wooden church were performed by employing nondestructive and destructive methods. The wood essence was established, with its “health” status being investigated by FTIR (Fourier Transform Infrared) spectroscopy and DSC (Differential Scanning Calorimetry) thermal analysis. The painting materials employed by popular artists were determined by FTIR and XRF (X-ray fluorescence) spectroscopy as gypsum, calcite (rear background), lead white (Archangel Clothes), lead-minium (Archangel Clothes, leaf), iron oxide (Imperial Gate frame), malachite (green), Prussian blue (blue), orpiment (yellow), aliphatic, ester, and protein (probably egg yolk degradation products). Using similar colors as in the original artwork (resulting from the scientific investigation of the pigments) a 3D reconstruction has been performed. The restored Imperial Gates are placed in the old Nicula wooden church, being included into a tourist and religious circuit. I. Bratu, Monk Siluan, C. Măruţoiu, I. Kacso, S. Garabagiu, V. C. Măruţoiu, C. Tănăselia, D. Popescu, D. L. Postolache, and D. Pop Copyright © 2017 I. Bratu et al. All rights reserved. Rapid Detection of Pesticide Residues in Chinese Herbal Medicines by Fourier Transform Infrared Spectroscopy Coupled with Partial Least Squares Regression Tue, 27 Dec 2016 12:33:07 +0000 http://www.hindawi.com/journals/jspec/2016/9492030/ This paper reports a simple, rapid, and effective method for simultaneous detection of cartap (Ca), thiocyclam (Th), and tebufenozide (Te) in Chinese herbal medicines including Radix Angelicae Dahuricae and Liquorices using Fourier transform infrared spectroscopy (FT-IR) coupled with partial least squares regression (PLSR). The proposed method can handle the intrinsic interferences of herbal samples; satisfactory average recoveries attained from near-infrared (NIR) and mid-infrared (MIR) PLSR models were and % for Ca, and % for Th, and and % for Te, respectively. Furthermore, some statistical parameters and figures of merit are fully investigated to evaluate the performance of the two models. It was found that both models could give accurate results and only the performance of MIR-PLSR was slightly better than that of NIR-PLSR in the cases suffering from herbal matrix interferences. In conclusion, FT-IR spectroscopy in combination with PLSR has been demonstrated for its application in rapid screening and quantitative analysis of multipesticide residues in Chinese herbal medicines without physical or chemical separation pretreatment step and any spectral processing, which also implies other potential applications such as food and drug safety, herbal plants quality, and environmental evaluation, due to its advantages of nontoxic and nondestructive analysis. Tianming Yang, Rong Zhou, Du Jiang, Haiyan Fu, Rui Su, Yangxi Liu, and Hanbo Su Copyright © 2016 Tianming Yang et al. All rights reserved. Application of Optical Spectrophotometry for Analysis of Radiation Spectrum Emitted by Electric Arc in the Air Mon, 26 Dec 2016 11:32:31 +0000 http://www.hindawi.com/journals/jspec/2016/1814754/ This paper presents the results of measurement and analysis of optical radiation emitted by a free burning electric arc. The aim was to determine the application possibilities of optical spectrophotometry for detection of electric arcs. The research works considered electric arc generated with a constant voltage supply between two copper electrodes in the air, carried out under laboratory conditions. A high resolution optical spectrophotometer was used for registration of optical radiation. The analyses involved determination of two dimensionless descriptors obtained for the gathered spectra. Moreover, for each of the registered intensity distributions, the energy values were calculated for three frequency ranges. Based on the measured signals, the possibility of application of spectrophotometry for the optical radiation analysis was confirmed. The analysis indicated that the most energy of optical radiation is detected for the range of 200–780 nm, while above 780 nm almost no optical energy is emitted. Spectrophotometric studies performed in the UV-NIR range are of interest since one can obtain information about the structural defects (at lower wavebands) or impurities and/or point defects (at low energies bands). It was also stated that the obtained descriptors may be applied for diagnosis and identification of electric arc purposes. Michał Kozioł, Daria Wotzka, Tomasz Boczar, and Paweł Frącz Copyright © 2016 Michał Kozioł et al. All rights reserved. Corrigendum to “Background Radiance Estimation for Gas Plume Quantification for Airborne Hyperspectral Thermal Imaging” Mon, 19 Dec 2016 14:55:31 +0000 http://www.hindawi.com/journals/jspec/2016/4616050/ Ramzi Idoughi, Thomas H. G. Vidal, Pierre-Yves Foucher, Marc-André Gagnon, and Xavier Briottet Copyright © 2016 Ramzi Idoughi et al. All rights reserved. XPS and GDOES Characterization of Porous Coating Enriched with Copper and Calcium Obtained on Tantalum via Plasma Electrolytic Oxidation Mon, 19 Dec 2016 12:31:57 +0000 http://www.hindawi.com/journals/jspec/2016/7093071/ XPS and GDOES characterizations of porous coatings on tantalum after Plasma Electrolytic Oxidation (PEO) at 450 V for 3 minutes in electrolyte containing concentrated (85%) phosphoric acid with calcium nitrate and copper (II) nitrate are described. Based on the obtained data, it may be concluded that the PEO coating consists of tantalum (Ta5+), calcium (Ca2+), copper (Cu2+  and Cu+), and phosphates (). It has to be pointed out that copper and calcium are distributed throughout the volume. The authors also propose a new model of PEO, based on the derivative of GDOES signals with sputtering time. Krzysztof Rokosz, Tadeusz Hryniewicz, Patrick Chapon, Steinar Raaen, and Hugo Ricardo Zschommler Sandim Copyright © 2016 Krzysztof Rokosz et al. All rights reserved. Light Manipulation by Single Cells: The Case of Diatoms Wed, 14 Dec 2016 11:44:06 +0000 http://www.hindawi.com/journals/jspec/2016/2490128/ Diatoms are ubiquitous monocellular microalgae, responsible for about 20–25% of the global oxygen produced by photosynthesis. Living in environments where sunlight is not so easily accessible, evolution shaped diatoms in order to exploit light with high efficiency. In particular, diatoms are provided with an external, micro- and nanopatterned silica shell, the frustule, surprisingly similar to artificial photonic crystals and able to manipulate light in many different ways. The present paper reviews the most relevant studies on optical and photonic properties of diatoms that have been performed throughout the last years making use of SEM characterizations, transmittance measurements at different wavelengths, holographic microscopy, Raman spectroscopy and imaging, photoluminescence spectroscopy, and the predictive support of different numerical simulation algorithms. Edoardo De Tommasi Copyright © 2016 Edoardo De Tommasi. All rights reserved. Enamel Based Composite Layers Deposited on Titanium Substrate with Antifungal Activity Mon, 12 Dec 2016 09:02:02 +0000 http://www.hindawi.com/journals/jspec/2016/4361051/ The goal of this paper was to investigate the antifungal activity of Enamel layers deposited on titanium substrate (Ti-Enamel) and Enamel layers deposited on titanium substrate previously coated with a vinyl polydimethylsiloxane layer (Ti-PDMS-Enamel). The physicochemical properties were also investigated. The Candida albicans biofilm development on the obtained layers was examined after 24 h, 48 h, and 72 h by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) after ethidium bromide staining. A significant inhibition of the fungal adherence and biofilm development was observed on Ti-Enamel layers. The antifungal results demonstrated that the use of new Ti-Enamel composite layers could represent a promising perspective for the prevention of fungal biofilms associated implant infections. S. L. Iconaru, A. M. Prodan, C. S. Turculet, M. Beuran, R. V. Ghita, A. Costescu, A. Groza, M. C. Chifiriuc, P. Chapon, S. Gaiaschi, R. Hristu, G. A. Stanciu, R. Trusca, M. Ganciu, S. M. Raita, N. Vineticu, and C. S. Ciobanu Copyright © 2016 S. L. Iconaru et al. All rights reserved. Bromide-Assisted Anisotropic Growth of Gold Nanoparticles as Substrates for Surface-Enhanced Raman Scattering Wed, 07 Dec 2016 13:07:44 +0000 http://www.hindawi.com/journals/jspec/2016/3164247/ We report herein a one-step synthesis of gold nanoparticles (Au NPs) of various shapes such as triangles, hexagons, and semispheres, using 5-hydroxyindoleacetic acid (5-HIAA) as the reducing agent in the presence of potassium bromide (KBr). Anisotropic Au NPs have received ever-increasing attention in various areas of research due to their unique physical and chemical properties. Numerous synthetic methods involving either top-down or bottom-up approaches have been developed to synthesize Au NPs with deliberately varied shapes, sizes, and configurations; however, the production of templateless, seedless, and surfactant-free singular-shaped anisotropic Au NPs remains a significant challenge. The concentrations of hydrogen tetrachloroaurate (HAuCl4), 5-HIAA, and KBr, as well as the reaction temperature, were found to influence the resulting product morphology. A detailed characterization of the resulting Au NPs was performed using ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy. The as-prepared Au NPs exhibited excellent surface-enhanced Raman scattering (SERS) properties, which make them very attractive for the development of SERS-based chemical and biological sensors. Melissa A. Kerr and Fei Yan Copyright © 2016 Melissa A. Kerr and Fei Yan. All rights reserved. Study of Molecular and Ionic Vapor Composition over CeI3 by Knudsen Effusion Mass Spectrometry Mon, 05 Dec 2016 14:17:37 +0000 http://www.hindawi.com/journals/jspec/2016/2368131/ The molecular and ionic composition of vapor over cerium triiodide was studied by Knudsen effusion mass spectrometry. In the saturated vapor over CeI3 the monomer, dimer, and trimer molecules and the negative ions I−, , and were identified in the temperature range of 753–994 K. The partial pressures of CeI3, Ce2I6, and Ce3I9 were determined and the enthalpies of sublimation, (298.15 K) in kJ·mol−1, in the form of monomers (), dimers (), and trimers () were obtained by the second and third laws of thermodynamics. The enthalpy of formation, (298.15 K) in kJ·mol−1, of the CeI3 (), Ce2I6 (), and Ce3I9 () molecules and the () and () ions were calculated. The electron work function, =  eV, for the CeI3 crystal was evaluated. A. M. Dunaev, V. B. Motalov, L. S. Kudin, M. F. Butman, and K. W. Krämer Copyright © 2016 A. M. Dunaev et al. All rights reserved. XRD Investigation of Some Thermal Degraded Starch Based Materials Mon, 05 Dec 2016 14:14:27 +0000 http://www.hindawi.com/journals/jspec/2016/9605312/ The thermal degradation of some starch based materials was investigated using XRD method. The samples were obtained by thermal extrusion of mixtures of different proportions of starch, glycerol, and water. Such materials are suitable for the manufacturing of low pollutant packaging. Thermal degradation is one of the simplest ways to destroy such materials and this process is followed by structural modification of the local ordering of samples, water evaporation, crystallization, oxidation, or destruction of the chemical bonds. These modifications need to be studied in order to reduce to the minimum production of pollutant residues by burning process. XRD measurements show modification of the local ordering of the starch molecules depending on the temperature and initial composition of the samples. The molecular ordering perturbation is more pronounced in samples with low content of starch. Mihai Todica, Elena Mihaela Nagy, Carmen Niculaescu, Oana Stan, Nicolae Cioica, and Cornel Viorel Pop Copyright © 2016 Mihai Todica et al. All rights reserved. Quantitative Classification of Quartz by Laser Induced Breakdown Spectroscopy in Conjunction with Discriminant Function Analysis Sun, 04 Dec 2016 12:47:32 +0000 http://www.hindawi.com/journals/jspec/2016/1835027/ A responsive laser induced breakdown spectroscopic system was developed and improved for utilizing it as a sensor for the classification of quartz samples on the basis of trace elements present in the acquired samples. Laser induced breakdown spectroscopy (LIBS) in conjunction with discriminant function analysis (DFA) was applied for the classification of five different types of quartz samples. The quartz plasmas were produced at ambient pressure using Nd:YAG laser at fundamental harmonic mode (1064 nm). We optimized the detection system by finding the suitable delay time of the laser excitation. This is the first study, where the developed technique (LIBS+DFA) was successfully employed to probe and confirm the elemental composition of quartz samples. A. Ali, M. Z. Khan, I. Rehan, K. Rehan, and R. Muhammad Copyright © 2016 A. Ali et al. All rights reserved. Raman Spectroscopy in Colorectal Cancer Diagnostics: Comparison of PCA-LDA and PLS-DA Models Mon, 28 Nov 2016 12:38:18 +0000 http://www.hindawi.com/journals/jspec/2016/1603609/ Raman spectra of human colorectal tissue samples were employed to diagnose colorectal cancer. High-quality Raman spectra were acquired from normal and cancerous colorectal tissues from 81 patients. Subtle Raman variations, such as for peaks at 1134 cm−1 (protein, C-C/C-N stretching) and 1297 cm−1 (lipid, C-H2 twisting), were observed between normal and cancerous colorectal tissues. The average peak intensity at 1134 and 1297 cm−1 was increased from approximately 235 and 72 in the normal group, respectively, to 315 and 273 in the cancer group. The variations of Raman spectra reflected the changes of cell molecules during canceration. The multivariate statistical methods of principal component analysis-linear discriminant analysis (PCA-LDA) and partial least-squares-discriminant analysis (PLS-DA), together with leave-one-patient-out cross-validation, were employed to build the discrimination model. PCA-LDA was used to evaluate the capability of this approach for classifying colorectal cancer, resulting in a diagnostic accuracy of 79.2%. Further PLS-DA modeling yielded a diagnostic accuracy of 84.3% for colorectal cancer detection. Thus, the PLS-DA model is preferable between the two to discriminate cancerous from normal tissues. Our results demonstrate that Raman spectroscopy can be used with an optimized multivariate data analysis model as a sensitive diagnostic alternative to identify pathological changes in the colon at the molecular level. Wenjing Liu, Zhaotian Sun, Jinyu Chen, and Chuanbo Jing Copyright © 2016 Wenjing Liu et al. All rights reserved. Investigation by Raman Spectroscopy of the Decomposition Process of HKUST-1 upon Exposure to Air Mon, 28 Nov 2016 08:08:51 +0000 http://www.hindawi.com/journals/jspec/2016/8074297/ We report an experimental investigation by Raman spectroscopy of the decomposition process of Metal-Organic Framework (MOF) HKUST-1 upon exposure to air moisture ( K, 70% relative humidity). The data collected here are compared with the indications obtained from a model of the process of decomposition of this material proposed in literature. In agreement with that model, the reported Raman measurements indicate that for exposure times longer than 20 days relevant irreversible processes take place, which are related to the occurrence of the hydrolysis of Cu-O bonds. These processes induce small but detectable variations of the peak positions and intensities of the main Raman bands of the material, which can be related to Cu-Cu, Cu-O, and O-C-O stretching modes. The critical analyses of these changes have permitted us to obtain a more detailed description of the process of decomposition taking place in HKUST-1 upon interaction with moisture. Furthermore, the reported Raman data give further strong support to the recently proposed model of decomposition of HKUST-1, contributing significantly to the development of a complete picture of the properties of this considerable deleterious effect. Michela Todaro, Antonino Alessi, Luisa Sciortino, Simonpietro Agnello, Marco Cannas, Franco Mario Gelardi, and Gianpiero Buscarino Copyright © 2016 Michela Todaro et al. All rights reserved. Ultraviolet Spectroscopy Used to Fingerprint Five Wild-Grown Edible Mushrooms (Boletaceae) Collected from Yunnan, China Wed, 16 Nov 2016 07:53:34 +0000 http://www.hindawi.com/journals/jspec/2016/7813405/ Nowadays, wild-grown edible mushrooms which are natural, nutritious, and healthy get more and more popular by large consumers. In this paper, UV spectra of different Boletaceae mushrooms with the aid of partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were shown to be a practical and rapid method for discrimination purpose. The specimens of Boletus edulis, Boletus ferrugineus, Boletus tomentipes, Leccinum rugosiceps, and Xerocomus sp. were described based on the UV spectra. From the results, all the specimens were characterized by strong absorption at the wavelengths of 274 and 284 nm and showed the shoulder at 296 nm. However, changes could be seen in the peak heights at the same wavelength for different samples. After analyzing by chemometrics, visual discrimination among samples was presented and the relationships among them were also obtained. This study showed that UV spectroscopy combined with chemometrics methods could be used successfully as a simple and effective approach for characterization of these five wild-grown edible mushrooms at species and genus levels. Meanwhile, this rapid and simple methodology could also provide reference for the discrimination of edible mushrooms. Yan Li, Ji Zhang, Tao Li, Tianwei Yang, Yuanzhong Wang, and Honggao Liu Copyright © 2016 Yan Li et al. All rights reserved. Solid-State 13C NMR Spectroscopy Applied to the Study of Carbon Blacks and Carbon Deposits Obtained by Plasma Pyrolysis of Natural Gas Wed, 16 Nov 2016 06:18:33 +0000 http://www.hindawi.com/journals/jspec/2016/1543273/ Solid-state 13C nuclear magnetic resonance (NMR) spectroscopy was used in this work to analyze the physical and chemical properties of plasma blacks and carbon deposits produced by thermal cracking of natural gas using different types of plasma reactors. In a typical configuration with a double-chamber reactor, N2 or Ar was injected as plasma working gas in the first chamber and natural gas was injected in the second chamber, inside the arc column. The solid residue was collected at different points throughout the plasma apparatus and analyzed by 13C solid-state NMR spectroscopy, using either cross polarization (CP) or direct polarization (DP), combined with magic angle spinning (MAS). The 13C CP/MAS NMR spectra of a number of plasma blacks produced in the N2 plasma reactor showed two resonance bands, broadly identified as associated with aromatic and aliphatic groups, with indication of the presence of oxygen- and nitrogen-containing groups in the aliphatic region of the spectrum. In contrast to DP experiments, only a small fraction of 13C nuclei in the plasma blacks are effectively cross-polarized from nearby 1H nuclei and are thus observed in spectra recorded with CP. 13C NMR spectra are thus useful to distinguish between different types of carbon species in plasma blacks and allow a selective study of groups spatially close to hydrogen in the material. Jair C. C. Freitas, Daniel F. Cipriano, Carlos G. Zucolotto, Alfredo G. Cunha, and Francisco G. Emmerich Copyright © 2016 Jair C. C. Freitas et al. All rights reserved. Quantitative Estimating Salt Content of Saline Soil Using Laboratory Hyperspectral Data Treated by Fractional Derivative Thu, 10 Nov 2016 13:13:21 +0000 http://www.hindawi.com/journals/jspec/2016/1081674/ Most present researches on estimation of soil salinity by hyperspectral data have focused on the spectral reflectance or their integer derivatives but ignored the fractional derivative information of hyperspectral data. Motivated by this situation, the selected study area is the Ebinur Lake basin located in the southwest border in the Xinjiang Uygur Autonomous Region, China, with severe salinization. The field work was conducted from 15 to 25 October, 2014, and a total of 180 soil samples were collected from 45 sampling sites; after measuring the soil salt content and spectral reflectance in the laboratory, the range from 0 to 2 was divided into 11 orders (interval 0.2) and then the hyperspectral data were treated by 4 kinds of mathematical transformations and 11 orders of fractional derivatives. Combined with the soil salt content, partial least square regression method was applied for model calibrations and predictions and some indexes were used to evaluate the performance of models. The results showed that the retrieval model built up by 250 bands based on 1.2-order derivative of 1/ had excellent capacity of estimating soil salt content in the study area ( g/kg,  g/kg, , , and RPD = 2.080). This study provides an application reference for quantitative estimations of other land surface parameters and some other applications on hyperspectral technology. Dong Zhang, Tashpolat Tiyip, Jianli Ding, Fei Zhang, Ilyas Nurmemet, Ardak Kelimu, and Jingzhe Wang Copyright © 2016 Dong Zhang et al. All rights reserved. Speciation in Solutions of Lithium Salts in Dimethyl Sulfoxide, Propylene Carbonate, and Dimethyl Carbonate from Raman Data: A Minireview Sun, 06 Nov 2016 09:59:05 +0000 http://www.hindawi.com/journals/jspec/2016/6978560/ Our recent Raman studies of cation and anion solvation and ion pairing in solutions of lithium salts in dimethyl sulfoxide, propylene carbonate, and dimethyl carbonate are briefly overviewed. Special attention is paid to differences in our and existing data and concepts. As follows from our results, cation solvation numbers in solutions are low (~2) and disagree with previous measurements. This discrepancy is shown to arise from correct accounting for dimerization, hydrogen bonding, and conformation equilibria in the solvents disregarded in early studies. Another disputable question touches upon the absence of free ions in solutions of lithium salts in carbonate solvents and the statement that the charge transfer in carbonate solutions is caused by SSIPs. Direct proofs of the nature of charge carriers in the solvents studied have been obtained by means of analyses of vibrational dynamics. It has been found that collision times for free anions are short and evidence weak interactions between anions and solvent molecules. In SSIPs, collision times are an order of magnitude longer thus signifying strong interactions between anions and cations. In CIPs, collision times become shorter than in SSIPs reflecting the transformation of the structure of concentrated solutions to that of molten salts. M. I. Gorobets, M. B. Ataev, M. M. Gafurov, and S. A. Kirillov Copyright © 2016 M. I. Gorobets et al. All rights reserved. Rapid Detection of Tetracycline Residues in Duck Meat Using Surface Enhanced Raman Spectroscopy Wed, 02 Nov 2016 11:04:55 +0000 http://www.hindawi.com/journals/jspec/2016/1845237/ A rapid detection method based on surface enhanced Raman spectroscopy (SERS) was proposed in this paper in order to realize the detection of tetracycline residues in duck meat. Firstly, surface enhanced Raman spectra characteristics of tetracycline aqueous solution, duck meat extract, and duck meat extract containing tetracycline were analyzed. Secondly, the effect of the addition amount of duck meat extract containing tetracycline on SERS intensity and the effect of the adsorption time on SERS intensity were discussed, respectively. Thirdly, SERS intensity ratio at 1272 and 1558 cm−1 () was used to establish the SERS calibration curve. A good linearity relationship between the tetracycline concentration in duck meat extract and was obtained, and the linear regression equation and the correlation coefficient () were and 0.950, respectively. The average recovery of tetracycline in duck meat extract was 101~108% with relative standard deviation (RSD) of 2.4~4.6%. The experimental results showed that the method proposed in this paper was a good detection scheme for the rapid detection of tetracycline residues in duck meat. Jinhui Zhao, Ping Liu, Haichao Yuan, Yijie Peng, Qian Hong, and Muhua Liu Copyright © 2016 Jinhui Zhao et al. All rights reserved. Optical Properties of DMA-π-DCV Derivatives: A Theoretical Inspection under the DFT Microscope Tue, 01 Nov 2016 07:02:57 +0000 http://www.hindawi.com/journals/jspec/2016/3520698/ The optical properties of a series of donor-acceptor N,N-dimethylaniline-π-dicyanovinylene (DMA-π-DCV) chromophores have been investigated under the density functional theory framework. Focus has been made on the low-lying charge-transfer (CT) electronic transitions for which experimental data is available. The effect of the π-conjugated bridge length and type was analysed between the families of oligoene and oligoyne derivatives of increasing size. Theoretical calculations demonstrate that the ethylene bridge is a better π-communicator and allows for more delocalized frontier molecular orbitals compared to the acetylene spacer. The diagnostic test allowed rationalization of the orbital spatial overlap in the main CT excitations. The performance of different density functional rungs was assessed in the prediction of the lowest-lying CT electronic transition. Surprisingly, most modern long-range corrected functionals demonstrated to provide among the largest errors, whereas hybrid functionals showed the best performance. Solvatochromism was confirmed in both oligoene and oligoyne compounds. A donor-acceptor-donor triad based on tetrathiafulvalene was utilised as a test system for the prediction of its two CT bands of different nature, energy, and intensity. The hybrid PBE0 (or a similar hybrid analogue) consolidates as the best choice for the prediction of CT excitations in the DMA-π-DCV push-pull family. Joaquín Calbo Copyright © 2016 Joaquín Calbo. All rights reserved. Spectral Quantitative Analysis Model with Combining Wavelength Selection and Topology Structure Optimization Wed, 19 Oct 2016 12:46:49 +0000 http://www.hindawi.com/journals/jspec/2016/5616503/ Spectroscopy is an efficient and widely used quantitative analysis method. In this paper, a spectral quantitative analysis model with combining wavelength selection and topology structure optimization is proposed. For the proposed method, backpropagation neural network is adopted for building the component prediction model, and the simultaneousness optimization of the wavelength selection and the topology structure of neural network is realized by nonlinear adaptive evolutionary programming (NAEP). The hybrid chromosome in binary scheme of NAEP has three parts. The first part represents the topology structure of neural network, the second part represents the selection of wavelengths in the spectral data, and the third part represents the parameters of mutation of NAEP. Two real flue gas datasets are used in the experiments. In order to present the effectiveness of the methods, the partial least squares with full spectrum, the partial least squares combined with genetic algorithm, the uninformative variable elimination method, the backpropagation neural network with full spectrum, the backpropagation neural network combined with genetic algorithm, and the proposed method are performed for building the component prediction model. Experimental results verify that the proposed method has the ability to predict more accurately and robustly as a practical spectral analysis tool. Qian Wang, Boyan Cai, Yajie Yu, and Hui Cao Copyright © 2016 Qian Wang et al. All rights reserved. Detection of Melamine in Soybean Meal Using Near-Infrared Microscopy Imaging with Pure Component Spectra as the Evaluation Criteria Tue, 18 Oct 2016 08:15:12 +0000 http://www.hindawi.com/journals/jspec/2016/5868170/ Soybean meal was adulterated with melamine with the purpose of boosting the protein content for unlawful interests. In recent years, the near-infrared (NIR) spectroscopy technique has been widely used for guaranteeing food and feed security for its fast, nondestructive, and pollution-free characteristics. However, there are problems with using near-infrared (NIR) spectroscopy for detecting samples with low contaminant concentration because of instrument noise and sampling issues. In addition, methods based on NIR are indirect and depend on calibration models. NIR microscopy imaging offers the opportunity to investigate the chemical species present in food and feed at the microscale level (the minimum spot size is a few micrometers), thus avoiding the problem of the spectral features of contaminants being diluted by scanning. The aim of this work was to investigate the feasibility of using NIR microscopy imaging to identify melamine particles in soybean meal using only the pure component spectrum. The results presented indicate that using the classical least squares (CLS) algorithm with the nonnegative least squares (NNLS) algorithm, without needing first to develop a calibration model, could identify soybean meal that is both uncontaminated and contaminated with melamine particles at as low a level as 50 mg kg−1. Zengling Yang, Lujia Han, Chengte Wang, Jing Li, Juan A. Fernández Pierna, Pierre Dardenne, and Vincent Baeten Copyright © 2016 Zengling Yang et al. All rights reserved. Photoreflectance and Raman Study of Surface Electric States on AlGaAs/GaAs Heterostructures Sun, 16 Oct 2016 07:52:31 +0000 http://www.hindawi.com/journals/jspec/2016/4601249/ Photoreflectance (PR) and Raman are two very useful spectroscopy techniques that usually are used to know the surface electronic states in GaAs-based semiconductor devices. However, although they are exceptional tools there are few reports where both techniques were used in these kinds of devices. In this work, the surface electronic states on AlGaAs/GaAs heterostructures were studied in order to identify the effect of factors like laser penetration depth, cap layer thickness, and surface passivation over PR and Raman spectra. PR measurements were performed alternately with two lasers (532 nm and 375 nm wavelength) as the modulation sources in order to identify internal and surface features. The surface electric field calculated by PR analysis decreased whereas the GaAs cap layer thickness increased, in good agreement with a similar behavior observed in Raman measurements ( ratio). When the heterostructures were treated by Si-flux, these techniques showed contrary behaviors. PR analysis revealed a diminution in the surface electric field due to a passivation process whereas the ratio did not present the same behavior because it was dominated by the depletion layers width (cap layer thickness) and the laser penetration depth. Luis Zamora-Peredo, Leandro García-González, Julián Hernández-Torres, Irving E. Cortes-Mestizo, Víctor H. Méndez-García, and Máximo López-López Copyright © 2016 Luis Zamora-Peredo et al. All rights reserved. Construction of Spectral Discoloration Model for Red Lead Pigment by Aging Test and Simulating Degradation Experiment Thu, 01 Sep 2016 16:05:05 +0000 http://www.hindawi.com/journals/jspec/2016/3517496/ The construction of spectral discoloration model, based on aging test and simulating degradation experiment, was proposed to detect the aging degree of red lead pigment in ancient murals and to reproduce the spectral data supporting digital restoration of the ancient murals. The degradation process of red lead pigment under the aging test conditions was revealed by X-ray diffraction, scanning electron microscopy, and spectrophotometer. The simulating degradation experiment was carried out by proportionally mixing red lead and lead dioxide with referring to the results of aging test. The experimental result indicated that the pure red lead was gradually turned into black lead dioxide, and the amount of tiny particles of the aging sample increased faced with aging process. Both the chroma and lightness of red lead pigment decreased with discoloration, and its hue essentially remains unchanged. In addition, the spectral reflectance curves of the aging samples almost started rising at about 550 nm with the inflection moving slightly from about 570 nm to 550 nm. The spectral reflectance of samples in long- and in short-wavelength regions was fitted well with the logarithmic and linear function. The spectral discoloration model was established, and the real aging red lead pigment in Dunhuang murals was measured and verified the effectiveness of the model. Jinxing Liang, Xiaoxia Wan, Chan Li, Junfeng Li, Qiang Liu, and Qian Cao Copyright © 2016 Jinxing Liang et al. All rights reserved. Fourier Transform Infrared Spectroscopy of “Bisphenol A” Tue, 23 Aug 2016 14:24:18 +0000 http://www.hindawi.com/journals/jspec/2016/2073613/ FTIR (400–4000 cm−1) spectra of “Bisphenol A” are presented. Absorption peaks (400–4000 cm−1) are assigned on the basis of Density Functional Theory (DFT) with configuration as B3LYP 6-311G++ (3df 3pd). Calculated absorption peaks are in reasonable reconciliation with experimental absorption peaks after scaling with scale factor of 0.9679 except C-H and O-H stretching vibrations. Ramzan Ullah, Ishaq Ahmad, and Yuxiang Zheng Copyright © 2016 Ramzan Ullah et al. All rights reserved. Spectroscopic Investigations of the Oxidative Polymerization of Hydroquinone in the Presence of Hexavalent Chromium Mon, 22 Aug 2016 14:11:36 +0000 http://www.hindawi.com/journals/jspec/2016/7958351/ Polyphenol polymerization receives much scientific attentions because it is an important reaction of humification processes. Through an oxidative polymerization reaction (OPR), hydroquinone (H2Q), a naturally occurring compound, has been found to be a vital precursor of humic substances in soils. Chromate (Cr(VI)), a strong oxidant, is widely distributed in the environment due to the inappropriate disposal of Cr-containing wastes. The OPR of H2Q in the presence of Cr(VI) may occur naturally. In the study, it was found that 400 mg L−1 H2Q could be polymerized at pH 3.0 with 105 mg L−1 Cr(VI). The results of FT-IR revealed the presence of both hydroquinone and benzoquinone nuclei in the polymer. The spectra of X-ray absorption near edge structure (XANES) demonstrated a decrease in Cr(VI) content during the OPR of H2Q. Based on the results of linear combination fitting (LCF) for the spectra of XANES, the proportions of Cr species in the precipitates mainly consisted of Cr(OH)3, and Cr-carboxylate contents increased gradually from 15.3 to 25.5% over the reaction time. After acidizing the supernatants at pH 1.0 for 1 d, Cr(III)-HA dominated Cr(III) species. This suggested that humic-like substances were formed during OPR of H2Q, possibly through the formation of Cr(III)-organic complex. Ching-Yun Cheng, Ya-Ting Chan, Yu-Min Tzou, Kai-Yue Chen, and Yu-Ting Liu Copyright © 2016 Ching-Yun Cheng et al. All rights reserved.