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This study utilized density functional theory (DFT) in quantum chemistry to investigate the gas-phase parasitic reaction mechanism between diethylzinc (DEZn) and tert-butanol (t-BuOH) during the metal-organic chemical vapor deposition (MOCVD) growth process of ZnO thin films. By calculating the Gibbs free energy changes along various reaction pathways at different temperatures, a comprehensive thermodynamic evaluation of key intermediates (HOZnOBut, H(ZnO)2 But, HZnOH), as well as the formation of dimers (Zn2 O2 H4, Zn2 O4 H4, Zn4 O4 H4), and trimers (Zn3 O6 H6) was performed. The main objective was to identify potential pathways and products that could lead to the formation of nanoparticles, which might impede ZnO thin film growth. Research has shown that under high-temperature deposition conditions (673.15 K

In order to explore the stability of cluster NiPS3 and the mechanism of isomerization transformation, in this paper, density functional theory was used to optimize the initial configuration of cluster NiPS3 and calculate the isomerization under the quantum chemistry calculation level of B3LYP/def2-tzvp. Ten optimal configurations and seven isomerization transformation types were obtained. Based on the thermodynamics and kinetics of chemical reactions, the following conclusions are drawn: the isomerization transformation of cluster NiPS3 depends on the bonding and bonded breaking between non-metal and non-metal. The greater the difference between the stability of reactants and products, the more thorough the reaction. Except reaction 2(2)→1(4), other isomerization reactions are more spontaneous at low temperature. The isomerization reaction tends to proceed in the forward direction, that is to say, the higher energy configuration is easier to convert to the lower energy configuration. Configurational 1(2), configurational 2(2) and configurational 1(4) are the final products of cluster NiPS3 isomerization, and could be given priority in the research, development and production of related materials. [ABSTRACT FROM AUTHOR]

In this work, the s-binanyl-pyrene is selected as the research object. Then the structure of s-binanyl-pyrene in the gas phase, as well as the dihedral angle of binaphthalene, energy gap, electronic circular dichroism（ECD） spectra and other properties were investigated by using the density functional theory method. On this basis, we systematically investigated the solvent effects and substituent effects of s-binanyl-pyrene. Our results indicated that, for s-binanyl-pyrene in benzene, carbon tetrachloride, chloroform, cyclohexane and water, the obtained structures and ECD spectra are very similar. However, among the substituting groups of methyl, chlorine, phenyl, hydroxy and methoxy on s-binanyl-pyrene, structure and ECD spectra properties will be adjusted by the phenyl group. [ABSTRACT FROM AUTHOR]

Dyes in water have been widely discovered, and dye pollution is one of the important factors for the water pollution, due to the wide application of dyes in food, printing, textile and other industries. Therefore, pretreatment of dyes in water has become extremely important. The adsorption properties of pure and functionalized graphene can be applied to the detection and removal of dyes in water. In this study, the adsorption mechanism of pure graphene and functionalized graphene on methylene blue (MB) was investigated by density functional theory method. The results showed that pure graphene and functionalized graphene have a certain degree of adsorption of MB, among which the adsorption of functionalized graphenes on MB is stronger than that of pure graphene on MB. There is the strongest adsorption of graphene functionalized with epoxy, carboxyl and hydroxyl three groups. The results are hopeful to provide meaningful theoretical guidance for graphene materials in the adsorption application of organic dyes. [ABSTRACT FROM AUTHOR]

Three isotropic heteropoly acid ionic liquid models were constructed, and their microstructures, binding energies and carrier effective masses were analyzed and discussed in the framework of density functional theory. The results show that the number of substituted coordination atoms of heteropoly acid has a great influence on the properties of the compound. In molybdenum-substituted phosphotungstic acid, when the number of molybdenum-substituted phosphotungstic acid is low, the effective mass of the hybrid carrier is low and the conductivity is strong. With high molybdenum substitution number, the carrier’s relative mass is larger, so the transmission resistance increases, and its conductivity is better than that of the complexes with low molybdenum substitution number. This paper predicts and verifies the properties of the synthesized materials, and provides theoretical basis and guidance for the synthesis and analysis of this kind of materials in the future. [ABSTRACT FROM AUTHOR]

Mechanism degradation of ethylene terephthalate momer was investigated by density functional theory B3P86/6-31++G (d, p) method, the possible reaction paths of pyrolysis/hydrolysis/alcoholysis and catalytic degradation were designed, the geometric structures of various intermediates, transition states, and products involved in the reaction were optimized, and their frequencies were calculated to gain the thermodynamic and kinetic parameters. The calculation results show that: When water or methanol is used as a catalyst in the ethylene terephthalate process of thermal degradation, the use water or methanol O-H provides H to the main chain of the ethylene terephthalate ester bond on the carbonyl O atom is form terephthalic acid, and ethyl C off H atoms and (water) hydroxyl (-OH) or (methanol) methoxy group (-OCH3) are combined to form new water or methanol, thereby reducing the reaction energy barriers during the pyrolysis of ethylene terephthalate (251.4 kJ/mol→181.1 kJ/mol (methanol) and 187.5 kJ/mol (water)). When water or methanol is reactant in the thermal degradation process of ethylene terephthalate, H in water or methanol O-H is supplied to the carbonyl O atom of the main chain of ethylene terephthalate to form ethylene glycol. Hydroxy group (-OH) in water or methoxy group (-OCH3) in methanol binds to the carbonyl C atom of the carbonyl group of ethylene terephthalate backbone to form terephthalic acid or mono-methyl terephthalate, it further reduces the reaction energy barriers (156.4 kJ/mol (methanol) and 170.1 kJ/mol (water)) during the pyrolysis of ethylene terephthalate. In the reaction process, either water/methanol as catalysis or water/methanol as reactants can reduce the reaction energy barrier of the main element step to a certain extent, so that the reaction is easy to proceed. [ABSTRACT FROM AUTHOR]

The normal Raman spectrum and surface enhanced Raman spectrum (SERS) in silver nanomaterial of pseudo ephedrine were studied in this article. Geometry structure and theoretical Raman spectrum of pseudo ephedrine were studied by density functional theory method using B3LYP/6-311G++(d, p), and the vibrational modes were assigned comprehensively by software of Gauss view. The silver cluster nanomaterial substrate was fabricated by self-assembling and achieved good enhancement effect in SERS of pseudo ephedrine. The results showed that the theoretically calculated spectrum of pseudo ephedrine was consistent with the experimental spectrum. Theoretical calculation provided significant basis for assigning the vibrational peaks. The molecule was absorbed on the silver surface, and the benzene ring was perpendicular to the surface. The study provides a strong theoretical basis for the spectroscopy research of pseudo ephedrine, also supplies important reference for the spectroscopy research of amphetamine drugs. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2) is a thermally induced phase change material, the high phase change temperature restricts its potential application. Elemental doping can cause the changes in the properties of VO2 such as band structure, state density, bond length and cell volume, resulting in the change of phase transition behavior. Using Materials Studio software, based on first principles and molecular orbital theory, the crystal structure evolution and phase transformation mechanism of Gd and F doped VO2 were studied, it was found that no matter F doping in the middle O position of VO2 (M) or O position on both sides, the doping will cause O—O bond to contract, V—V bond to growth, β Angle to increase, system Helmholm self-energy to increase, band gap to be relative reduction, F on both sides of the doping effect is the best. With the decrease of V4+—V4+ unipolar bonding, the phase transition temperature reaches the lowest at 1at% F doping. When Gd is doped in V position in VO2 (M) at 0-1.8at%, O—O bond and V—V bond shrink, β Angle decreases, Helmholm self-energy increases, band gap decreases, and Gd 4f state coincides with tⅡ orbital, so that the phase transition energy barrier becomes lower and the phase transition temperature decreases significantly. The phase transition mechanism of gadolinium and fluorine doped VO2 is more consistent with Peierls-Mott synergistic phase transition. [ABSTRACT FROM AUTHOR]

Adopting ligand occupation strategy and the principle of molecular self-assembly, a mononuclear cobalt (III) complex [CoIII(DIEN)(N3)3] (1, DIEN = diethylenetriamine) was synthesized by solution method using diethylenetriamine as the organic ligand and Co3+ as the central metal ion at room temperature. Single crystal of complex 1 was obtained. The structural characterization and electronic structure analysis were carried out through X-ray single crystal diffraction, elemental analysis, and quantum chemical calculations. Single crystal X-ray diffraction analysis reveals that complex 1 is triclinic, space group of P1 with a =0. 825 3(2) nm, b =0. 892 0(3) nm, c = 0. 898 7(3) nm, α = 106. 497(4)°, β = 90. 281(4)°, γ = 113. 861(4)°, V = 0. 574 7(3) nm³. The central ion Co(III) has an elongated octahedral configuration. Each complex is composed of Co3+ cation, three azide anions and one diethylenetriamine ligand. A disordered azide anion has a site occupancy of 50%, and 1D chain-like supermolecular was formed by N-H...N hydrogen bond and π...π packing interations. In addition, based on crystal structure of complex 1 determined by X-ray crystallographic analysis, the full geometry optimized and frequency calculations have been performed by density functional theory. The single-point energy, atomic charges and frontier molecular orbital were analyzed. The theoretical calculation results indicate that the complex configuration is stable and consistent with the experimental results. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quinoxaline compounds are widely used in the fields of medicine and chemical industry, especially in the development of anticancer drugs, due to their significant biological activity. 6-fluoro-4-hydroxy-3-oxo-3,4-dihydroquinoline-1 (2H)-carboxylic acid tert-butyl ester was synthesized through a four-step reaction method in this paper, and its single crystal was obtained by solution crystallization method. Crystallographic analysis indicates that the compound belongs to monoclinic crystal system with space group C2/c, the unit cell dimensions are a =1.286 63(10) nm, b =2.252 49(17) nm, c =1.015 64(7) nm, Z =8, ρc =1. 359 g·cm-3, R =0. 053 8, Rw =0. 140 6. The optimal structure was calculated using density functional theory (DFT) in B3LYP/6-311 + G (2d, p) mode. The results are basically consistent with those obtained by X-ray single crystal diffraction. The antitumor activity study shows that the compound has good antitumor effect. In addition, the electrostatic potential and frontier molecular orbitals of the molecules were calculated by DFT to further understand their physical and chemical properties. [ABSTRACT FROM AUTHOR]

The crystal structure and elastic properties of chromium tetraboride (CrB4) were investigated by pseudopotential plane-wave methods within the Perdew-Burke-Ernzerhof (PBE) form of generalized gradient approximation (GGA). The calculated equilibrium structural parameters of Pnnm-CrB4 are in good agreement with the available experimental data and other theoretical results. Moreover, the elastic constants Cij, bulk modulus B, shear modulus G and elastic modulus E under high pressure were calculated, and the toughness and brittleness of Pnnm-CrB4 under high pressure were analyzed with the Poisson ratio σ and B / G. To study the elastic anisotropy of Pnnm-CrB4 in detail, the anisotropic factors A1, A2, A3 for shear and Ba, Bb, Bc for the directional bulk modulus were also calculated. The Vickers hardness HV of Pnnm-CrB4 was estimated at the same time. Finally, the total and partial density of states of Pnnm-CrB4 under high pressure were studied so as to have a better understanding of the mechanical and elastic properties of Pnnm-CrB4. [ABSTRACT FROM AUTHOR]

Kinetics simulation model for the degradation of sulfachlorpyridazine (SCP) in Fe(III)/sulfite (Fe(III)-S(IV)) system was established, and the reaction mechanism of different radicals in this system was also investigated. The reactive species were identified by electron spin resonance experiments, anaerobic experiment, quenching experiments and PMSO experiment, and their contributions were also analyzed. It was showed that the main reactive species at pH=4 in the system were SO4•-, SO5•- and •OH, and the contribution of each radicals were 76.3%, 22.3% and 1.40%, respectively. The results were consistent with the kinetics simulation. Subsequently, the main reaction sites of SCP were calculated by density functional theory, and the intermediate products of SCP degradation by SO4•- or SO5•- were analyzed by LC-MS. The degradation pathways and mechanisms of different radicals in S(IV) system were improved and verified. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This is an article in the field of mineral processing engineering. Fatty acid collectors are widely used in the flotation of oxidized ores, and the molecular structure is an important factor affecting the flotation performance. To reveal the effect of the structural change of fatty acid collector on its reaction activity from the microscopic point of view, the relationship between electronic structure and properties of fatty acid collectors was studied by the density functional theory. The research results show that the oxygen atom in oleic acid molecule and oleate ion has strong reaction activity, which is the bonding atom of oleic acid interaction with oxidized minerals. The two oxygen atoms of oleate ion have similar chemical activity, and the density of states at Fermi level is higher than that of oleic acid molecule, which makes the activity of oleate ion much stronger than that of oleic acid molecule. The length of the carbon chain and the unsaturation of the alkyl have almost no effect on the density of states of the oxygen atoms in fatty acids, their effect on the properties of fatty acids is not through the action of carboxyl groups. The interaction energy between fatty acids and common metal cations is consistent with the decrease of their solubility product constants, and there is a good corresponding relationship between them. The research has certain theoretical significance and reference value for understanding the relationship between the structure and performance of fatty acid collectors and developing new fatty acid collectors.

The inorganic scales have negative effects on the development of oilfields and result in the decrease of economics. This paper analyzed the components and location of the inorganic scales in C oilfields by combining indoor experiments and simulations. A new neutral supramolecular detergent by γ-polyglutamic acid and other agents was prepared. The self-assembly process of the supramolecular system was analyzed and clarified by Materials Studio 2020. Meanwhile, the descaling effect and system applicability of the supramolecular detergent and traditional acidic detergent were compared and evaluated. Molecular simulation by density functional theory(DFT) and indoor experiments were applied to analyze the scale removal mechanisms of the supramolecular system. The results showed that the calcium/magnesium carbonate and ferrous carbonate scales were the main inorganic scales of the typical wells in oilfields at the bottom holes. The removal rates of supramolecular detergent for calcium carbonate scale, calcium sulfate scale and simulated scale were 74.2%, 45.1%, and 65.8%, respectively, which were obviously higher than those of the traditional detergents. The flooding experiments showed that the core injection pressure could be increased 12% after using supramolecular detergent. The optimum temperature of the supramolecular detergent was 40-90 ℃ and the optimum reaction time was 12 hours. The dynamic simulation analysis showed that although steric hindrance affected the adsorption of ions by supramolecular systems, supramolecular systems were more likely to chelate scale samples due to larger intermolecular interactions. The scale removal mechanisms could be summarized as a synergy of supramolecular coordination, supramolecular aggregation and permeation. Therefore, the new supramolecular detergent had a good prospect for application.

In order to explore the formation pathways of 5-(α-D-glucopyranosyl-(1-6)-α-D-glucopyranosyloxymenthyl)-2-furancarboxaldehyde (5-GGMF), a pigment formed during the process of sugar smoking, the thermal decomposition reaction site of sucrose, the dehydration reaction modes between glucose and 5-hydroxymethylfurfural (5-HMF) and between two molecules of glucose, and the formation pathways of 5-HMF and 5-GGMF were analyzed by quantum chemical calculation. The results showed that the initial position of thermal decomposition of sucrose was the cleavage of fructosyl-oxygen bond. van der Waals force played a leading role in the complexes formed by the interaction between glucose and 5-HMF and between two molecules of glucose, and the intermolecular dehydration reaction was promoted by strong hydrogen bonding. The formation of 5-HMF from the glucose moiety formed after the pyrolysis of sucrose needed more activation energy than from the fructose moiety formed with a lower reaction rate, indicating that the fructose moiety was more prone to form 5-HMF. Among the two formation pathways of 5-HMF from the fructose moiety, pathway 5 was more prone to occur than pathway 4, because pathway 5 showed obvious advantages in energy and reaction kinetics. In the formation pathways of 5-GGMF from sucrose, the energy barrier of the transglycosylation pathway was overall lower, which was more favorable than the disaccharide dehydration and trisaccharide dehydration pathways. Among them, pathway C2, including three steps: the pyrolysis of sucrose to produce fructose and glucose, the reaction of glucose with 5-HMF to form 5-glucosyloxymethylfurfural (5-GMF), and the reaction of 5-GMF with a molecule of free glucose to produce 5-GGMF, was most conducive to the generation of 5-GGMF from both an energy barrier and kinetic perspective. The results of this study can provide a theoretical basis and reference for controlling and intervening in the color of sugar smoked products in the future.

Purposes In order to obtain additional microstructural information on the ConMoS(n＝1-5) cluster and establish a theoretical foundation for subsequent investigations of its electronic properties and catalytic performance, the atomic interaction relationships and frontier orbital compositions of the cluster are investigated. Methods To accomplish this, density functional theory with the B3LYP functional and def2-TZVP basis set is adopted to optimize the cluster configuration and perform theoretical analysis under various spin multiplicities with the Gaussian09 software package. Findings The results demonstrate the existence of 21 stable configurations. AIM theory, electron localization function, and deformation density are analyzed to obtain information on the degree of internal interaction and electron density transfer trends of the cluster. The findings indicate that covalent bonding interactions between Co, Mo, and S atoms are strong in the internal atom interactions of the cluster, with S atoms exhibiting high localization and low probability of electron escape from the domain. In contrast, Co and Mo atoms exhibit strong delocalization and are likely to exchange electrons with the outside electrons. Through Hirshfeld analysis of atomic contribution rates, it can be observed that metal atoms are the primary contributors to the HOMO and LUMO orbitals, with Mo and Co atoms dominating the frontier orbitals. Overall, covalent bonding is the primary atomic interaction within the cluster, but the strength of these interactions varies. Mo and Co atoms should be the focus in chemical reactions of the cluster.

In this study, 12 phenolic acids were theoretically calculated using the M06-2X functional. To explain their antioxidant and solvation effects, bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) were calculated for each phenolic acid in the gas phase and solvents. The results showed that the BDE of gentianic acid (C5) in the gas phase was the lowest. In terms of BDE, caffeic acid (C6) had the strongest antioxidant effect in benzene, gentianic acid (C5) in acetone, and 3,4-dihydroxybenzyl alcohol (C2) in ethanol and water. In terms of IP, resveratrol had the best antioxidant activity in 4 solvents and in the gas phase. The antioxidant mechanism of phenolic acids was mainly related to hydrogen atom transfer (HAT). It was found that the ability of dehydrogenated anions and cations of phenolic acids to generate dehydrogenated free radicals was consistent with the influence of solvent polarity on IP, BDE, PDE, PA and ETE. In general, the antioxidant capacity of phenolic acids was the strongest in the weakly polar solvent acetone, followed by the strongly polar solvents water and ethanol, and phenolic acids had the weakest antioxidant capacity in non-polar solvents.

Sulfamethoxazole（SMX） is a broad-spectrum sulfonamide antibiotic. In this study, the B3LYP method of density functional theory（DFT） was used to optimize the initial configuration at the level of the B3LYP/6-311 + + G（d, p） basis set, and the most stable molecular structure was obtained. The bond length, bond angle and dihedral angle patameter values of SMX were given, and the molecule exhibited a non-planar structure. The frequency calculation was conducted at the same basis set level, and the infrared and Raman spectra of SMX were corrected and plotted using a frequency correction factor of 0.9630. The spectral bands were found to be mainly distributed in the frequency bands of 3600-2800 cm-1 and 1700-300 cm-1, and there are good agreement between the theoretically calculated and experimentally measured values, indicating that the DFT calculation method is desirable and credible. The GaussView 6.0 software package and the calculated potential energy distribution were used to assign each vibration mode within the frequency range. In addition, the electrostatic potential and frontline molecular orbitals of the SMX molecule were calculated and analyzed using the Multiwfn and VMD programs to predict the reactive sites of the molecule. These results provide basic data for detecting the vibration spectrum of SMX and are technical reference for its structural identification. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of the reaction between thioether and 2-methyl-1,5-hexadiene was investigated in detail by using density functional theory. The calculation results show that the reaction process mainly includes three parts: the generation of the three-membered metallacycle active species, the insertion of 2-methyl-1,5-hexadiene, and the subsequent CH activation of another molecule of thioether. In the process of 2-methyl - 1,5 - hexadiene insertion, it is suitable for more favorable a 6-5-re - face insertion due to the lower energy barrier, and it is relatively easy to complete the closed-loop reaction followed by the in- sertion of the carbon-carbon double bond. The whole reaction process is controlled by C-H activation step ow- ing to the highest energy barrier. [ABSTRACT FROM AUTHOR]

The photocatalyst NaTaO3, owing to its notable chemical and thermal stability as well as environmental friendliness, emerges as a versatile candidate capable of meeting diverse demands across various fields. Through ion doping, it is feasible to modulate the electronic structure and performance of NaTaO3. In this study, employing density functional theory (DFT), electronic structure and optical properties of perovskite-type Na0. 75 B0. 25 TaO3 (where B = Cr, Mn, Fe, Cu, Zn) were systematically investigated, elucidating the impact of different transition metal dopants on the band structure and electron density of states in NaTaO3. The investigation reveals that Cr, Mn, Fe, and Zn doping induces metallic properties, while Na0.75 Cu0.25 TaO3 exhibits semiconductor characteristics, accompanied by a narrowed bandgap of 1. 35 eV. The introduction of Cu introduces new energy levels (Cu 3d and Cu 4s) within the bandgap, positioned at its center, resulting in an upward shift of the valence band. Furthermore, the absorption spectra in the Cu-doped system exhibit a redshift, extending the light absorption wavelength up to 800 nm. Subsequently, the photocatalytic antibacterial performance of NaTaO3 and Na0.75 Cu0.25 TaO3 was explored, demonstrating a bactericidal efficiency of 99. 99% against Staphylococcus aureus (S. aureus) following Cu ion modulation. Finally, an analysis of potential antibacterial mechanisms was undertaken. [ABSTRACT FROM AUTHOR]

The crystal structures, electronic structures, atomic populations, charge density distributions and birefringence of Li2 MoO4, Na2 MoO4, K2 MoO4 and Rb2 MoO4 were compared by first principles. The results show that the bandgaps of the four crystals are direct band gaps, the differences of the bandgap between them are not large, and they are all around 4. 3 eV. As the radius of alkali metal atoms increases, the contribution of their electronic orbitals to the energy bands moves closer to the high-energy side. The distribution of the bonding boule number and electron density suggests that covalent bonds are formed between Mo and O, and the alkali metal atoms form ionic bonds with O. Rb2 MoO4 has the highest birefringence of 0. 022 5 among the four crystals at 1 064 nm. The refractive indices of the four crystals show that the radius is positively correlated with the birefringence. The study in this paper provides some references for the application of molybdate in nonlinear optical crystals. [ABSTRACT FROM AUTHOR]

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In order to study the corrosion effect of vitamin corrosion inhibitor in reinforced concrete systems, the effects of thiamine (VitB1), nicotinic acid (VitB3), pyridoxine (VitB6) and ascorbic acid (VitC) on steel reinforcement in simulated pore solutions of concrete containing chlorine was investigated using dynamic potential polarization and electrochemical impedance spectroscopy tests. The mechanism of vitamin corrosion inhibition on steel reinforcement was also discussed based on density general function theory with quantum chemical calculations. The results show that VitB6 has the best corrosion inhibition effect in simulated pore solution of concrete containing 0.05 mol/L NaCl because of the strongest bonding stability between its highest occupied molecular orbital and the 3d orbital of iron. All four vitamins have a specific concentration value to achieve the best corrosion inhibition effect IE. At this time, VitB1 and VitB3 are anodic corrosion inhibitors and VitB6 and VitC are mixed corrosion inhibitors. With the increase of vitamin concentration, the IE tends to fluctuate inversely, which is due to the inhibition of cathodic reaction caused by the adsorption of polar groups on steel surface, further aggravating the imbalance between cathode and anode. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heterobifunctional reactive dyes are widely used to dye cotton and protein fabrics owing to their characteristic such as excellent dyeing fastness high lightfastness and wide range of colors. The primary cause of color fading and coloring during the washing of cotton fabrics is the hydrolysis of covalent bonds between dyes and cellulose. However at present people are only familiar with the mechanism of hydrolysis of covalent bonds formed between individual active groups and cellulose such as the common halogenated homotriazine group and vinyl sulfone group. Specifically the ether bond formed by halotriazine active group and cellulose and the ether bond formed by vinyl sulfone group and cellulose will be hydrolyzed under alkaline conditions. Halogenated triazine reactive group will be hydrolyzed into hydroxytriazine and vinyl sulfone reactive group will be hydrolyzed into β-hydroxyethyl sulfone while the reaction mechanism that results in the breaking of covalent bonds between different reactive groups and cellulose molecules remains unclear. Based on the principle of quantum mechanics quantum chemical calculations can accurately simulate the movement and interaction of electrons as well as the formation and fracture of chemical bonds. These make predicting the properties of molecules and reactions without relying on experimental data possible. Thus quantum chemical calculations are widely used to describe molecular structures reaction mechanisms and energy changes. The wave function theory and density-functional theory DFT are two important parts of quantum chemical calculations. The frontier molecular orbital FMO and conceptual density functional theory CDFT are two representative theories to predict and rationalize molecular reactivity qualitatively and quantitatively. Some chemical reaction descriptors obtained from CDFT like Fukui function chemical hardness or softness electrophilicity or nucleophilicity are a new type of structural index specially used to describe the chemical reactivity of substances. This article combined wave function theory and CDFT to investigate chemical characteristics of the hydrolysis pathway of the covalent bond between heterobifunctional reactive dye and cellulose under alkaline conditions with the heterobifunctional reactive dye named Reactive Yellow 210 RY210 being used as an example. In order to reduce the complexity of the model the chromophores in RY210 molecule that are not related to the reaction were replaced by hydrogen atoms. At the same time according to previous studies cellobiose was substituted for cellulose molecules. The research process was divided into three steps. Firstly the possible pathways and products of RY210 and cellulose polymer were conjectured based on the hydrolysis mechanism of the covalent bond between a single reactive group dye and cellulose. The ether bond formed by the active group of triazine group and cellulose will be hydrolyzed into hydroxytriazine and the ether bond formed by the active group of vinyl sulfone and cellulose will be β-eliminated to generate vinyl sulfone which will be further hydrolyzed into β-hydroxyethyl sulfone. Based on this known mechanism it is hypothesized that there are seven possible hydrolysis pathways which involve hydrolysis of one reactive group alone followed by the other reactive group as well as hydrolysis of both reactive groups at the same time. Secondly the study constructed a dye-cellulose polymer model. To do this the study investigated the sites on the cellobiose molecule where OH - is easy to react with using electrostatic potential ESP frontier molecular orbital theory FMO and two chemical reaction descriptors CFF and CDD based on DFT. The model was constructed by taking into account their three spatial arrangements of the cellobiose and dye molecules in orthogonal anticlinal parallel and perpendicular directions. Then these structures were optimized by MD simulations and the most stable polymer structure was identified. Further the study calculated the Gibbs free energies of different hydrolysis pathways based on the theory of M06-2X∕6-311G d . Additionally the local nucleophilic reactivity of dye-cellulose compounds at the bonding sites of triazine and vinyl sulfone groups with OH- was compared to further verify the previous conclusions. The findings demonstrate that the cellobiose-dye polymer was readily hydrolyzed at the bonding with vinyl sulfone but could be hydrolyzed at the bonding with triazine difficultly. The covalent bonding of vinyl sulfone with OH - displayed higher nucleophilic activity. Initially the ether bond was hydrolyzed to form vinyl sulfone with a reaction energy barrier of 17. 1 kcal∕mol. Following this vinyl sulfone was hydrolyzed to produce β-hydroxyethyl sulfone with a reaction energy barrier of 27. 8 kcal∕mol. The nucleophilic reactivity at the homotriazine group was the lowest and the homotriazine group was hydrolyzed into hydroxytriazine with a significant amount of energy at 48. 6 kcal∕mol. This study is helpful to further understand the mechanism of hydrolysis of heterobifunctional reactive dyes from cellulose under alkaline conditions. At the same time the study also provides some ideas for slowing down the fading of heterobifunctional dyes from fabrics and washing crossovers as well as designing efficient and environmentally friendly reactive dyes. [ABSTRACT FROM AUTHOR]

This paper uses density functional theory to calculate the electronic properties, magnetism and CO2 adsorption performance of the manganese based metal organic framework (Mn - MOF) material{[Mn2(ina)4(H2O)2]・2EtOH}n The results show that this Mn - MOF is an antiferromagnetic coupling material. The high CO2 binding affinity of this Mn - MOF is mainly attributed to the higher charge transfer from the CO2 (the oxygen lone - pair electron used as the Lewis base) to the open metal site (Lewis acid). The high selective CO2 adsorption capacity of CO2/N2 flue gas mixture reported in the experiment is also verified, and the theoretical results are in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

In order to investigate the microscopic mechanism and the relationship between adsorbent materials in the process of CO2 capture by adsorption, the adsorption processes and differences between typical adsorbents in- cluding coal-based functional groups, Fe, restricted ionic liquids, Na2CO3 and SrTiO3 with CO2 were compared based on the density flooding theory approach. According to different calculation strategies, the parameters of ad- sorption energy, structural optimization parameters, adsorption configuration and atomic distribution are analyzed and compared. The results show that the adsorption energy is usually highest when the CO2 molecule is parallel to the adsorption surface in chemisorption; the adsorption energy is positively correlated with the number of oxygen atoms in the same type of functional group of a material; and the elongation activation of the C-O bond during adsorption produces an important intermediate product CO2. It is proposed that the search for CO2 adsorption materials can be further explored in terms of functional groups containing more oxygen atoms and reactive metal surfaces. Finally, further research on the adsorption mechanism of CO2 based on density functional theory has been expected in this paper. [ABSTRACT FROM AUTHOR]

The Pu or Am content in U-Pu and U-Am mixed oxides is crucial for the efficient recycling of nuclear reactor fuel. The effects of different Pu or Am contents in uranium-based mixed oxides on their structures, mechanical properties and energies can help to understand and predict the behavior of fuel in boost reactors and the chemical or mechanical interactions with the cladding. Therefore, in this work, the DFT + U method based on density functional theory is used to explore the relationships between the structure and energy of UO2, PuO2 and AmO2 with U, and then study the effect of different Pu or Am contents in the UO2 structure on its structure, mechanical properties and energy. The results show that the incorporation of Pu or Am into the UO2 structure reduces the lattice parameters, and both are between UO2 and PuO2 or AmO2. From the energy point of view, the different contents of Pu or Am into UO2 structure makes the variation trend of the formation energy of the system significantly different with the amount of doping. The formation energy of the U-Pu mixed oxide system is the lowest when the UO2 structure is doped with 25% Pu, while the U-Am mixed oxide system has the lowest formation energy when the UO2 structure is doped with 75% Am. In addition, we also discussed and analyzed the variation and difference of elastic parameters with different Pu or Am contents incorporated into the UO2 structure. [ABSTRACT FROM AUTHOR]

2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is one of the most significant one in dioxin families that harms humans and environment. It is an urgent problem to design an efficient and sensitive adsorbent in order to detect and remove the effects of 2,3,7,8-TCDD on humans and the environment In this study, the first-principles method based on density Functional theory (DFT) was used to explore the adsorption meschanism of 2,3,7,8 - TCDD on intrinsic phosphorene; and the effect of doping Ti, Fe, Ca, Al metal atoms into intrinsic phosphorene on the 2,3,7,8-TCDD adsorption was investigated in detail. The results demonstrated that the initial configuration of 2,3,7,8-TCDD affects the adsorption, and the adsorption is greater when lying flat on the intrinsic phosphorene surface. Moreover, the doping of metal atoms also has a great influence on the adsorption of 2,3,7,8-TCDD on the phosphorene surface. The metal atoms doping increases the adsorption between intrinsic phosphorene and 2,3,7,8-TCDD. Ca doped phosphorene > Fe doped phosphorene > Ti doped phosphorene > Al doped phosphorene. The conclusion brings new thinking for the treatment of 2,3,7,8 - TCDD and is expected to provide useful theoretical guidance for the detection and removal of dioxins. [ABSTRACT FROM AUTHOR]

In this paper, a new GaSe/ZnS van der Waals heterostructure (vdWH) is devised and subjected to systematic analysis through first principles calculations in terms of its geometric, electronic and transport properties. The stability of GaSe/ZnS vdWH is verified through binding energy, phonon spectrum, and ab initio molecular dynamics (AIMD) simulation. Additionally, detailed calculations of plane average electron density difference and average electrostatic potential in the features of GaSe/ZnS vdWH interface are provided. The results show that GaSe/ ZnS vdWH comprises a heterostructure with a direct band gap of 2.19 eV and high carrier mobility. Among them, the electron mobility along the x direction reaches 1 394.63 cm²V-1⋅s-1, while the electron mobility along the y direction reaches 1 913.18 cm² ⋅V-1 ⋅s-1, demonstrating excellent performance and potential applications in electronic nano devices. [ABSTRACT FROM AUTHOR]

This article employed a first-principles calculation method based on density functional theory to optimize the geometric structure of the ternary layered nitride M2 AlN (M = Ti, Zr). The structural, mechanical, electronic and optical properties of the ternary layered nitride M2 AlN (M = Ti, Zr) under high pressure were investigated. The study of structural and mechanical properties reveal that Ti2 AlN exhibits superior compressibility compared to Zr2 AlN. The elastic constants further validate its mechanical stability under high pressure. Ductility and elastic anisotropy enhance under increasing pressure, with Zr2 AlN demonstrating heightened sensitivity to these pressure conditions. Research on electronic properties reveals that both ternary layered nitrides exhibit metallic behavior, and their covalent character strengthen with increasing pressure. Investigations into the optical properties reveal that the polycrystalline nature and static dielectric functions ε1 (0), along with the static refractive index n(0) of Ti2 AlN and Zr2 AlN along various axes, demonstrate relatively low anisotropy in their optical characteristics. Both ternary nitrides exhibit pronounced capabilities for light absorption and reflectivity. Theoretical inquiries in this study clarified the relevant characteristics of the ternary layered nitrides Ti2 AlN and Zr2 AlN under the elevated pressure, establishing a robust theoretical framework for subsequent experimental investigations. [ABSTRACT FROM AUTHOR]

Photodetectors are widely used in various fields, such as industrial manufacturing and military defense. Researchers have recently sought a photodetector that combines high polarization sensitivity and a robust optical response. As an anisotropic semiconductor material, SnS holds potential for photodetection across the visible light spectrum. This study employs first-principles density functional theory (DFT) along with the non-equilibrium Green's function (NEGF) method to theoretically investigate the optoelectronic properties of the SnS monolayer in two device orientations: Armchair and Zigzag. It is found that the maximum photocurrent values between the two orientations are small at zero bias voltage, and stable photocurrent can be obtained by adding bias voltage. We examine the maximum photocurrent variation under linearly polarized light irradiation within a small bias voltage range (0.1 to 1.0 V), found for the maximum photoresponse of monolayer SnS to be large and stable at photon energy of 2.4 and 3.2 eV, and analyze the underlying mechanism of photoresponse, employing energy band and density of state diagrams. Additionally, we have calculated the extinction ratio of the SnS monolayer, confirming its strong polarization sensitivity. Finally, by subjecting the device to biaxial strain, we significantly speculate to enhance its asymmetry, leading to a substantial increase in photocurrent at zero bias. A compressive strain of - 6% notably increases the photocurrent. These findings offer valuable theoretical insights for the design of SnS monolayers as photodetectors. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using first principles density functional theory calculations, the crystal structure, electronic properties, and superconductivity characteristics of the ternary hydride Y-Si-H system under high pressure were investigated. The study revealed the existence of thermodynamically stable phases, including YSiH7, YSiH9, YSi2H12, and YSiH18, and thermodynamically metastable phases, namely YSi2H13, YSi2H14, and Y2SiH17. Electronic properties calculations showed that YSiH7 is insulator and YSi2H13 is semiconductor, while the remaining hydrides exhibit metallic properties. Superconducting transition temperatures (Tc) were estimated using the McMillan equation, with YSi2H12 hosting the highest Tc of 43.5 K at 100 GPa. The dynamic stable pressure of YSi2H14 can be reduced to 40 GPa, and its Tc is 23.8 K which is twice the highest Tc among binary Y-Si compounds, indicating that introducing H atom into Y-Si system can effectively increase the superconducting transition temperature. Y2SiH17 exhibits a Tc of 35.8 K at 100 GPa. Spectral function and electron-phonon coupling calculations suggested that in YSi2H14 and Y2SiH17, in addition to the H-induced superconductivity from mid-frequency vibrations, low-frequency vibrations of Y also play a significant role for superconductivity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To elucidate the microscopic mechanisms underlying the impact of hydrated cations on the surface hydration of slime mineral particles (specifically, kaolinite and quartz, the primary minerals in slime), this study focused on constructing two common hydrated cations in slime water: [Na(H2O)5]+ and [Ca(H2O)8]2+. Using density functional theory, the adsorption of these two hydrated cations on the surfaces of kaolinite (001), (\begin{document}$ 00\overline 1 $\end{document}) and α-quartz (001), as well as their competitive adsorption with water molecules were simulated. The simulation results revealed that the adsorption energy of hydrated cations on all three surfaces was over 50% lower than that of water molecules. The adsorption stability on mineral surfaces was as follows: α-quartz (001) surface > kaolinite (001) surface > kaolinite (\begin{document}$ 00\overline 1 $\end{document}) surface. The adsorption energy of the competitively stable configuration was 34%–57% lower than that of a single hydrated cation on kaolinite and quartz. Additionally, the [Ca(H2O)8]2+ configuration exhibited a greater stability than the [Na(H2O)5]+ configuration under both adsorption conditions. When the hydrated cations adsorbed onto three surfaces, strong hydrogen bonds formed with surface, surpassing the strength of hydrogen bonds between water molecules and kaolinite/quartz surfaces. The hierarchy of hydrogen bonds between two hydrated cations on mineral surfaces was as follows: kaolinite (001) surface > α-quartz (001) surface > kaolinite (\begin{document}$ 00\overline 1 $\end{document}) surface. Under a competitive adsorption, the hydrogen bond between [Na(H2O)5]+ and mineral surface strengthened, while the bond between [Ca(H2O)8]2+ and mineral surface weakened. Although hydrogen bonding did not entirely correlate with changes in adsorption energy, electrostatic interactions in the adsorption configuration were identified. The electrostatic interaction in the single adsorption configuration of hydrated cations proved stronger than that in water molecular adsorption. Under a competitive adsorption, the electrostatic interactions between hydrated cations and mineral surfaces intensified, with [Ca(H2O)8]2+ demonstrating stronger interaction than [Na(H2O)5]+. Given the robust adsorption of hydrated cations on the surfaces of kaolinite and quartz, the dehydration of slime particles becomes more challenging. This could increase hydration repulsion between particles, resulting in a more stable dispersion of particles in slime water.

为了促进国内橄榄油市场的健康发展，对掺伪同样存在天然类胡萝卜素的低温压榨菜籽油的特级初榨橄榄油进行了定量鉴别研究。采用共聚焦拉曼光谱技术对不同掺伪浓度油样进行测试，基于密度泛函理论对油样的拉曼光谱峰的归属进行了理论分析，并对拉曼光谱数据进行主成分分析（PCA），然后利用支持向量机（SVM）构建PCA-SVM模型。另外，对PCA-SVM模型的检出限进行了研究。结果表明：特级初榨橄榄油与低温压榨菜籽油的拉曼光谱存在一定差异，最明显的光谱差异主要集中在谱峰1 008、1 161、1 528 cm-1和谱段2 800～3 000 cm-1内，与密度泛函理论对不同油样拉曼光谱峰的分析一致；不考虑类胡萝卜素特征信号建立的PCA-SVM模型决定系数大于0.989，均方根误差小于2.990%，检出限为2%（低温压榨菜籽油体积分数）;在特级初榨橄榄油掺伪定量分析中，考虑类胡萝卜素的特征信号有助于提高模型预测精度，但仅限于掺伪低价植物油中无类胡萝卜素存在的情况;PCA-SVM模型在不考虑类胡萝卜素特征信号的情况下依然具有良好的定量预测效果。综上，所建立的PCA-SVM模型可以用于掺伪2%以上低温压榨菜籽油的特级初榨橄榄油的定量鉴别。To promote the healthy development of the domestic olive oil market, a study was conducted on quantitatively identifying extra virgin olive oil adulterated with low-temperature pressed rapeseed oil containing natural carotenoids. The confocal Raman spectroscopy technology was used to test oil samples with different adulteration amounts. Theoretical analysis was conducted on attributing Raman spectral peaks of different oil samples based on density functional theory. Principal component analysis (PCA) was performed on the Raman spectral data, and then the support vector machine (SVM) was used to construct a PCA-SVM model. In addition, the detection limit of the PCA-SVM model was studied. The results showed that there was difference in the Raman spectra of extra virgin olive oil and low-temperature pressed rapeseed oil, and the most apparent spectral differences mainly concentrated in the spectral peaks 1 008, 1 161, 1 528 cm-1 and spectral bands 2 800-3 000 cm-1, which was consistent with the analysis of Raman spectral peaks of different oil samples using density functional theory. The PCA-SVM model established without considering the characteristic signals of carotenoids had a coefficient of determination greater than 0.989, and the root mean square error was lower than 2.990%, and the detection limit was 2% (volume fraction of low-temperature pressed rapeseed oil). In the quantitative analysis of extra virgin olive oil adulteration, considering the characteristic signals of carotenoids could help to improve the prediction accuracy of the model, but it was only limited to the absence of carotenoids in adulterated low-price vegetable oils. The PCA-SVM model still had good quantitative prediction performance even when the characteristic signals of carotenoids were not considered. In summary, the established PCA-SVM model can be used to quantitatively identify extra virgin olive oil adulterated with over 2% low-temperature pressed rapeseed oil.

Metal organic frameworks (MOFs) are emerging porous materials connected through organic ligands, which have broad application prospects in gas storage, drug transportation, catalysis, and chemical sensing. This article provides an overview of the prediction and design of Fe based MOFs based on the combination of density functional theory (T)FT) and machine learning (ML). Tt provided a detailed description of the main synthetic methods for Fe-based MOFs materials and pointed out the crystal structure and coordination environment characteristics of these materials. The synthesis methods of Fe-MOFs based composites were summarized by combining nano powders. The applications of Fe MOFs and their composite materials in electrocatalytic nitrogen fixation, adsorption, conductivity, catalysis, and other properties were summarized, and the shortcomings in the current development of Fe MOFs and their composite materials were shown. Finally, a summary and outlook on Fe based MOFs and their composite materials were presented. [ABSTRACT FROM AUTHOR]

In order to study the electronic structure and magnetic properties of the non-rare earth based MnGa binary alloys under isostatic pressure, the crystal structure, formation, spin electronic structure as well as magnetic property of the tetragonal MnGa alloy under isostatic pressure of 500 MPa were systematically studied based on density functional theory calculation method. The results show that the tetragonal MnGa alloy can be formed easier, however the compressibility is anisotropic under the isostatic pressure of 500 MPa. The distances between heterogeneous species are smaller than that between the homogeneous species. The band structures are anisotropic and metallic. The Mn d states form higher net magnetic moment than that of the Ga d states in the MnGa alloy, and the Mn d states contribute to systematic remanent magnetism. The tetragonal MnGa alloy presents weak ferrimagnetism, its net magnetic moment decreases under 500 MPa. [ABSTRACT FROM AUTHOR]