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Theoretical material investigation based on density functional theory (DFT) has been a breakthrough in the last century. Nevertheless, the optical properties calculated by DFT ...generally show poor agreement with experimental results particularly when the absorption-coefficient (α) spectra in logarithmic scale are compared. In this study, we have established an alternative DFT approach (PHS method) that calculates highly accurate α spectra, which show remarkable agreement with experimental spectra even in logarithmic scale. In the developed method, the optical function estimated from generalized gradient approximation (GGA) using very high-density k mesh is blue-shifted by incorporating the energy-scale correction by a hybrid functional and the amplitude correction by sum rule. Our simple approach enables high-precision prediction of the experimental α spectra of all solar-cell materials (GaAs, InP, CdTe, CuInSe2 and Cu2ZnGeSe4) investigated here. The developed method satisfies the requirements of high accuracy and low computational cost simultaneously and is superior to conventional GGA, hybrid functional and GW methods.
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•CoM/TNTs showed high ACE degradation efficiency after PMS activation.•Efficient PMS activation was due to the synergic effect of Co(OH)2 and TNTs.•TNTs with abundant surface –OH ...facilitated formation of CoOH+.•PES analysis well explained the higher feasibility of Co(OH)+ on PMS activation.•ACE atoms with high Fukui index are active sites for electrophilic attack.
Pharmaceuticals and personal care products (PPCPs) are of great concern due to their increasing health effects, so advanced treatment technologies for PPCPs removal are urgently needed. In this study, titanate nanotubes decorated Co(OH)2 hollow microsphere (CoM/TNTs) composites were synthesized by a two-step solvothermal method, and used to activate peroxymonosulfate (PMS) through heterogenous catalysis for acetaminophen (ACE) degradation in water. The optimum material (CoM/TNTs0.5) activated PMS system exhibited high ACE removal efficiency and quick kinetic, as 93.0% ACE was degraded even within 10 min. The two components in CoM/TNTs showed a synergetic effect on PMS activation for radicals production: Co(OH)+ from CoM was the primary active species to active PMS, while TNTs could offer abundant –OH groups for Co(OH)+ formation. Density functional theory (DFT) calculation further interpreted the mechanism of Co(OH)+ for PMS activation by means of reaction potential energy surface (PES) analysis. Both the scavenger quenching tests and electron paramagnetic resonance analysis revealed that the sulfate radical (SO4-·) played a dominant role in ACE degradation. Moreover, DFT calculation also suggested that the ACE atoms with high Fukui index (f-) represented the active sites for electrophilic attack by SO4-·. The toxicity analysis based on quantitative structure-activity relationship (QSAR) verified the reduced toxicity of transformation products. Furthermore, CoM/TNTs also had good reusability and stability over five cycles. This work provides deep insights into the reaction mechanisms of radical production and organics attack in cobalt-based PMS activation system.
Shape effects of nanocrystal catalysts in different reactions have attracted remarkable attention. In the present work, three types of α-Fe
O
oxides with different micromorphologies were rationally ...synthesized via a facile solvothermal method and adopted in deep oxidation of ethane. The physicochemical properties of prepared materials were characterized by XRD, N
sorption, FE-SEM, HR-TEM, FTIR, in situ DRIFTS, XPS, Mössbauer spectroscopy, in situ Raman, electron energy loss spectroscopy, and H
-TPR. Moreover, the formation energy of oxygen vacancy and surface electronic structure on various crystal faces of α-Fe
O
were explored by DFT calculations. It is shown that nanosphere-like α-Fe
O
exhibits much higher ethane destruction activity and reaction stability than nanocube-like α-Fe
O
and nanorod-like α-Fe
O
due to larger amounts of oxygen vacancies and lattice defects, which greatly enhance the concentration of reactive oxygen species, oxygen transfer speed, and material redox property. In addition to this, DFT results reveal that nanosphere-like α-Fe
O
has the lowest formation energy of oxygen vacancy on the (110) facet ( E
(110) = 1.97 eV) and the strongest adsorption energy for ethane (-0.26 eV) and O
(-1.58 eV), which can accelerate the ethane oxidation process. This study has deepened the understanding of the face-dependent activities of α-Fe
O
in alkane destruction.
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•We proposed a series of transition metal borides (MBenes) monolayer as NRR catalysts.•MBenes exhibit metallic features and electrene characteristics for NRR activity.•Work function ...of the MBenes can be adopted as a descriptor for the NRR activity.
Low-energy consumption and highly selective nitrogen reduction reaction (NRR) catalysts play an important role in solving the limitations of the traditional ammonia production. By means of first-principle calculations, we proposed a series of two-dimensional (2D) transition metal borides (MB) (M = Sc, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W) monolayer as NRR catalysts. These 2D MBenes exhibit high stability, metallic electronic band structures and the electrene characteristics which contribute to the NRR catalytic activity. Large amounts of active sites accelerate the NRR reaction, and the high selectivity towards NRR inhibits the HER process. We screened out four MBenes: TiB, YB, ZrB and MoB, with favorable limiting overpotentials of 0.64, 0.68, 0.65 and 0.68 V, respectively, which are promising for N2 fixation applications. This work not only enriches the MBene family, but also provides a feasible strategy for the design of NRR catalysts.
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•Double azomethine functional Schiff bases protect mild steel in 1 mol L−1 HCl medium.•Inhibition efficiency obtained from EIS corroborates with the weight loss results.•Effect of ...molecular flexibility on its inhibition efficiency is described.•FESEM, AFM and contact angle measurements affirmed the adsorption of inhibitors on metal surface.•DFT, DFTB and MD simulation studies are in agreement with the experimental findings.
Two hitherto unexplored double condensed Schiff bases, namely, 4-(4-((Pyridin-2-yl)methyleneamino)phenoxy)-N-((pyridin-2-yl)methylene)benzenamine (PMB) and 4-(4-(4-((Pyridin-2-yl)methyleneamino)phenoxy)phenoxy)-N-((pyridin-2-yl)methylene)benzenamine (PPMB) were synthesized and their corrosion inhibitive performances on mild steel have been investigated in 1 mol L−1 HCl medium by gravimetric and electrochemical measurements. Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy affirmed the formation of protective films on mild steel surfaces. Contact angle measurement revealed the hydrophobic nature of surface modified by the inhibitor molecules applied in the corrosive solution. The influence of molecular configuration in corrosion inhibition behaviour of inhibitors has been explored by DFT, DFTB calculation and MD simulation.
•Structural acceleration of the shadow calculation was realized using a multithreaded framework.•The multithreaded shadow calculation framework can significantly shorten the calculation time.•The ...proposed shadow calculation method can achieve the same calculation accuracy.•The acceleration effect of multithreaded computing relates to the number of calculated surfaces.•For city-scale building shadow simulation, the calculation time is only 5.4% of the original time.
Solar radiation significantly affects the thermal processes of buildings; thus, various building energy modeling programs have established corresponding shadow calculation modules. However, the large number of projection surfaces in a building requires extensive calculations, making it difficult to rapidly analyze the building shadow while ensuring hourly calculations. This study proposes an accelerated calculation framework for building shadows based on multithreaded parallel computing for an accurate building energy consumption analysis. Based on the basic principle of shadow projection calculation, the embedded, integrated development of a shadow calculation module is proposed, and a full-performance simulation platform kernel based on a multithreaded structure is constructed. Results show that the multithreaded shadow calculation framework can significantly shorten the calculation time. Based on case studies, a typical complex single building’s shadow calculation speed can be increased by nearly 2.4 times, whereas for city-scale building shadow simulations, it is only 5.4% of the original duration.
Electromagnetic field inverse calculation plays a crucial role in solving the problem arising from the design and non-destructive testing of electromagnetic devices in engineering. In this study, an ...optimisation algorithm for electric field inverse calculation is proposed, which enables non-destructive detection of voltage on overhead transmission lines, enhances the robustness of the algorithm and improves the accuracy of calculation. Firstly, 2D and 3D calculation models of electric field are established. A multimedium calculation model with the operating environment of transmission lines considered is proposed. Based on the multimedium calculation method, the calculation environment is categorised into soil, vegetation, geology, and other media, and the correctness of the optimisation method is verified by the finite-element method-based model. Secondly, in order to eliminate the measurement noise and electric field distortion to the electric field measurement data, a modified model based on Kalman filter is constructed. Both multimedium calculation method and Kalman filter are applied to the inverse calculation of electric field as an optimisation electric field inverse solving algorithm. Finally, the inverse optimisation method is applied to 220 kV transmission lines and practical 500 kV ultra-high voltage transmission lines, respectively, to improve the accuracy and robustness of calculation.
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•2-Methyl-5-methylene-3-(2-methylbut-2-ene)-dicyclo (3, 3, 0)-octane core.•2-Methyl-4-methylene-2-(2-methylpent-2-ene)-dicyclo (3, 2, 0)-heptane scaffold.•Absolute configurations were ...determined NMR data, ECD, OR and 13C NMR calculations.
Three sesquiterpenoids pseudapenes A–C (1–3) were isolated from the marine-derived fungus Pseudallescheria apiosperma F52-1. Pseudapene A (1) has an unprecedented 2-methyl-5-methylene-3-(2-methylbut-2-ene)-dicyclo(3, 3, 0)-octane carbon skeleton and pseudapenes B (2) and C (3) possess an unique 2-methyl-4-methylene-2-(2-methylpent-2-ene)-dicyclo(3, 2, 0)-heptane chemical scaffold. Their structures were determined by use of MS and NMR spectroscopic data, and ECD, optical rotation and 13C NMR calculations.
Abinitis a material- and nanostructure-oriented package that implements density-functional theory (DFT) and many-body perturbation theory (MBPT) to find, from first principles, numerous properties ...including total energy, electronic structure, vibrational and thermodynamic properties, different dielectric and non-linear optical properties, and related spectra. In the special issue to celebrate the 40th anniversary of CPC, published in 2009, a detailed account of Abinitwas included Gonze et al. (2009), and has been amply cited. The present article comes as a follow-up to this 2009 publication. It includes an analysis of the impact that Abinithas had, through for example the bibliometric indicators of the 2009 publication. Links with several other computational materials science projects are described. This article also covers the new capabilities of Abinitthat have been implemented during the last three years, complementing a recent update of the 2009 article published in 2016. Physical and technical developments inside the abinitapplication are covered, as well as developments provided with the Abinitpackage, such as the multibinitand a-tdepprojects, and related Abinitorganization developments such as AbiPy. The new developments are described with relevant references, input variables, tests, and tutorials.
Program Title:Abinit
Program Files doi:http://dx.doi.org/10.17632/csvdrr4d68.1
Licensing provisions: GPLv3
Programming language: Fortran2003, Python
Journal reference of previous version: X .Gonze et al, Comput. Phys. Commun. 205 (2016) 106–131
Does the new version supersede the previous version?: Yes. The present 8.10.3 version is now the up-to-date stable version of abinit, and supercedes the 7.10.5 version.
Reasons for the new version: New developments
Summary of revisions:•Many new capabilities of the main abinitapplication, related to density-functional theory, density-functional perturbation theory, GW, the Bethe-Salpeter equation, dynamical mean-field theory, etc.•New applications in the package: multibinit(second-principles calculations)and tdep(temperature-dependent properties)
Nature of problem: Computing accurately material and nanostructure properties: electronic structure, bond lengths, bond angles, primitive cell, cohesive energy, dielectric properties, vibrational properties, elastic properties, optical properties, magnetic properties, non-linear couplings, electronic and vibrational lifetimes, etc. For large-scale systems, second-principles calculations, building upon the first-principles results, are also possible.
Solution method: Software application based on density-functional theory and many-body perturbation theory, pseudopotentials, with plane waves or wavelets as basis functions. Different real-time algorithms are implemented for second-principles calculations.
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