Using simple functionals of the electron density to appreciate and quantify molecular structure and chemical reactivity properties is a recent endeavor in density functional theory (DFT) toward the ...development of a new chemical reactivity theory. According to the first Hohenberg–Kohn theorem in DFT, the electron density alone should be able to determine any property in the ground state. Exchange and correlation energies are such properties, so are molecular structure and chemical reactivity, and hence they all should accurately be determined by electron density functionals. Quantities such as Shannon entropy, Fisher information, Ghosh–Berkowitz–Parr entropy, information gain, Onicescu information energy, etc., from the information‐theoretic approach are simple electron density functionals, whose analytical forms are exactly known. In this article, we demonstrate their usefulness and validity to quantify regioselectivity, stereoselectivity, and other structure and reactivity properties. We will outline the current understanding of its theoretical framework at first, and then highlight recent applications to chemical problems including isomeric and conformational stability, electrophilicity and nucleophilicity, strong covalent and weak noncovalent interactions, acidity and basicity, aromaticity and antiaromaticity, and numerous other properties. The effort of employing electron density functionals to quantify chemical concepts should open up a new door for us to ultimately develop a chemical reactivity theory using the DFT language.
This article is characterized under:
Structure and Mechanism > Reaction Mechanisms and Catalysis
Electronic Structure Theory > Density Functional Theory
Structure and Mechanism > Molecular Structures
Molecular and Statistical Mechanics > Molecular Interactions
Quantities from the information‐theoretic approach in density functional theory can quantitatively determine regioselectivity, stereoselectivity, electrophilicity, nucleophilicity, acidity, basicity, aromaticity, antiaromaticity, and many other properties related to electronic structure and chemical reactivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, OILJ, SBCE, SBMB, UPUK
Playing music in a concert represents a multilevel interaction between musicians and the audience, where interbrain synchronization might play an essential role. Here, we simultaneously recorded ...electroencephalographs (EEGs) from the brains of eight people during a concert: a quartet of professional guitarists and four participants in the audience. Using phase synchronization analyses between EEG signals within and between brains, we constructed hyperbrain networks, comprising synchronized brain activity across the eight brains, and analyzed them using a graph‐theoretical approach. We found that strengths within and between brains in the delta band were higher in the quartet than in the public. Within‐brain strengths were higher and between‐brain strengths were lower in the music than in the applause condition, both particularly in the quartet group. These changes in coupling strength were accompanied by corresponding changes in the hyperbrain network topology, which were also frequency‐specific. Moreover, the network topology and the dynamical structure of guitar sounds showed specific guitar–brain, guitar–guitar, and brain–brain directional associations, indicating multilevel dynamics with upward and downward causation. Finally, the hyperbrain networks exhibit modular structures that were more stable during music performance than during applause. Our findings illustrate complex hyperbrain network interactions in a quartet and its audience during a concert.
Playing music in a concert represents a multilevel interaction between musicians and the audience, where interbrain synchronization might play an essential role. Here, we simultaneously recorded EEGs from the brains of eight people during a concert: a quartet of professional guitarists and four participants in the audience. Using phase synchronization analyses between EEG signals within and between brains, we constructed hyperbrain networks, comprising synchronized brain activity across the eight brains, and analyzed them using a graph‐theoretical approach.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Corrosion inhibition of mild steel sample in hydrochloric acid solution was examined via weight loss and electrochemical measurements, Scanning Electron Microscopy (SEM) and X-ray Photoelectron ...Spectroscopy (XPS) techniques. The use of Lavandula mairei Humbert extract (LM) as an eco-friendly inhibitor of mild steel (MS) corrosion in 1 M HCl solution has significantly decreased MS corrosion rate. The corrosion inhibition efficiency increased with the increase of LM concentration up to 92% obtained at 303 K for a 0.4 g/ L concentration. The adsorption of LM inhibitor on the mild steel surface followed the Langmuir adsorption isotherm. Anodic Tafel slope digression and continuous CR lessening with the LM extract concentration increase, has validated the limited dissolution of mild steel. Theoretical approaches based on chemical quantum calculations and molecular dynamics simulation clearly explains the mode of adsorption of the majority molecule on the metal surface.
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•Lavandulamairei ethanol extract (LM) was used as a green corrosion inhibitor for mild steel.•SEM, EDX and XPS were applied on the steel surface to investigate the protective layer composition.•Theoretical study confirmed the adsorption of extract molecules on the steel surface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
When playing music in an ensemble, musicians need to precisely coordinate their actions with one another. As shown in our previous studies on guitar duets, interbrain synchronization plays an ...essential role during such interactions. In this study, we simultaneously recorded electroencephalograms from four guitarists during quartet playing, to explore the extent and the functional significance of synchronized cortical activity across four brains. We found that hyperbrain networks based on intra‐ and interbrain connectivity across four brains dwell on higher frequencies for intrabrain communication and on lower frequencies for interbrain connections. The hyperbrain networks show small‐world topology, with a tendency to become more random at lower frequencies and more regular at higher frequencies, such that local efficiency increases and global efficiency decreases with higher frequencies. We identified two different types of information flow within the hyperbrain networks—intra‐ versus intermodular—which are based on hyperbrain modules that include nodes from two, three, or even four brains. Furthermore, we found that hyperbrain networks are unstable and change their structure over time, often as a function of musical context. Our findings demonstrate complex hyperbrain network interactions in a guitar quartet and point to mechanisms that support temporally coordinated joint action.
When playing music in an ensemble, musicians need to precisely coordinate their actions with one another, and inter‐brain synchronization plays an essential role during such interactions. In this study, we simultaneously recorded electroencephalographs from the brains of four guitarists during quartet playing, demonstrating complex hyper‐brain network interactions and pointing to mechanisms that support temporally coordinated joint action.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
In this work the aim is three-fold: 1) to call attention for shielding effects in the energy transfer rates between lanthanide ions. 2) to use a new model for treating the Judd-Ofelt ΩK intensity ...parameters in centrosymmetric systems by using a thermal root mean squared displacement around each ligating atom (ion) in the analysis of the intensity parameters. This might have an important role in ion-ion energy transfer processes, particularly when the lanthanide ions occupy a center of inversion. 3) To call attention to the fact that the quadrupole-quadrupole mechanism is dominant for ion-ion distances as far as 20 Å, provided shielding effects are taken into account. An illustrating comparison with respect to the weak quadrupole mechanism of 4f‐4f transition rates is made.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
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In the present research, a new 1,3,4-thiadiazole derivative, namely the 2-amino-5-(2-methoxyphenyl)-1,3,4-thiadiazole (5-AMT) was synthesized and investigated as corrosion inhibitor ...for mild steel (M-steel) in molar hydrochloric acid medium. The experimental studies such as weight loss, potentiodynamic polarization (PDP), Linear polarization resistance (LPR) technique and electrochemical impedance spectroscopy (EIS) were performed in order to evaluate the corrosion protection performance of the tested compound. Based on the experimental outcomes, a protection degree of approximately 98 % was achieved exploiting 5 × 10−4 M of 5-AMT after 1 h of immersion at temperature 303 K. Additionally, PDP study highlighted that the investigated 1,3,4-thiadiazole is of mixed-kind inhibitor. Thermodynamic data from adsorption isotherms and activation energies were determined and discussed. It was shown that the adsorption of 5-AMT molecules fits Langmuir isotherm model. Furthermore, in order to characterize the M-steel surface and to comprehend the adsorption mechanism of 5-AMT, XPS analyses were accomplished. Computational studies by DFT and MD simulation were also conducted to correlate the protection properties and quantum chemical parameters of the investigated inhibitor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
•This paper provides a high-speed three-dimensional (3-D) shape measurement technique for dynamic scenes using geometry-constraint-based number-theoretical phase unwrapping.•Due to the reduction of ...fringe order candidates and the unambiguous phase range, the reliability of phase unwrapping can be significantly improved compared with the traditional number-theoretical TPU approach even when high-frequency fringe patterns are used.•The performance of our method in terms of noise resistance is discussed in detail. And the selection strategy of the optimal bi-frequency scheme is proposed to improve the stability of the absolute phase recovery under the condition of noise.
In this paper, we propose a high-speed three-dimensional (3-D) shape measurement technique for dynamic scenes using geometry-constraint-based number-theoretical phase unwrapping. As a classical algorithm for temporal phase unwrapping (TPU), the number-theoretical approach is suitable for the binary defocusing fringe projection system since it can retrieve an absolute phase without using low-frequency fringe patterns. However, the conventional number-theoretical TPU approach cannot provide sufficient stability to unwrap a high-frequency phase since it requires the two fringe frequencies to be coprime within the global range of the projector coordinate. In contrast, using low-frequency fringe patterns tends to make phase unwrapping more reliable, but at the expense of the measurement precision. By introducing depth constraint into the traditional number-theoretical TPU, we only need to eliminate the phase ambiguity of each pixel within a small period range defined by the depth range, which means that our method just requires the two fringe frequencies to be coprime within the local period range instead of the conventional global range. Due to the reduction of fringe order candidates and the unambiguous phase range, the reliability of phase unwrapping can be significantly improved compared with the traditional number-theoretical TPU approach even when high-frequency fringe patterns are used. The proposed method has been successfully implemented on a high-frame-rate fringe projection system, achieving high-precision, robust, and absolute 3-D shape measurement at 3333 frames per second.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
In the field of sociology, researchers require a theoretical approach when conducting scientific research due to its significant importance in laying the foundation for understanding the studied ...phenomenon. Many students and researchers inquire about the most suitable approach that contributes to providing the research with a conceptual model and intellectual and ideological frameworks. These frameworks support the researcher in the process of analysis and interpretation of the research topic, aiming to achieve logical sequence and methodological coherence throughout each stage of the research. Consequently, this article aims to explore the theoretical approach and its application in scientific research in the social sciences, relying on the following elements:
1) Concepts and meanings; 2) The relationship between theory and scientific research; 3) Why we need a theoretical approach in scientific research?; 4) Employing the theoretical approach in scientific research; 5) How to formulate the theoretical approach in the theoretical aspect.
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