查看更多>>摘要：The effect of high-pressure on the crystal structure of urea hydrogen peroxide has been investigated to 30 GPa. Through in-situ Raman scattering and ADXRD measurements, a first-order phase transition is concluded at 2.5GPa, and the new phase is indexed to a triclinic phase using Rietveld refinement method. Further increase in pressure up to 30 GPa does not show any structural phase transition. From the Raman analysis, the irreversible phase transition should be correlated with the twist structure of urea in the adduct of urea and hydrogen peroxide as a result of the cooperation and competition of inter-molecular hydrogen bonds.
查看更多>>摘要：Water transport through a single-walled carbon nanotube (SWCNT) with a small nanogap under a vertical electric field is studied by molecular dynamics simulations. Water transfer rate, water adsorption, water mobility and water orientation in the SWCNT with a nanogap decrease faster than that in the SWCNT without a nanogap with increasing the vertical electric field. The vertical electric field affects water properties by affecting the formation of a water bridge in the nanogap region. Our results are beneficial to design the energy-saving devices.
Dang, Cam-Tu PhanDuong, Long VanTuyn, Phan ToaiPham, Hung Tan...
8页
查看更多>>摘要：Geometries of doubly transition metal doped silicon clusters M(2)Sin, M-2 = Mo-2, Nb-2, Ta-2, W-2, NbMo, TaW were determined by DFT computations. Geometries of M(2)Sin in the range from 11 to 18 Si atoms change from a tubular shape to a cage and then a fused cage. The M2Si18 sizes present us with a novel structural motif, the fused cage, for silicon clusters. Such fused cages arise from a fusion of both MSi10 and MSi12 prisms followed by addition of two Si atoms. Formation and filling of electron shells contribute to the high thermodynamic stability of M2Si18 fused clusters.
查看更多>>摘要：We report a study of universality class change from Mean-Field to 3D-Heisenberg in magnetocaloric compounds SmNi3_xFex. Three conventional techniques are used to identify the universal classes: the Modified Arrott plot, Kouvel-Fisher plot, and critical isotherm technique. The calculated critical exponents were confirmed and the isotherm M(H) curves in paramagnetic state and ferromagnetic state fall in two separated universal branches. The exponents found are similar to those determined from the renormalization group approach for a heuristic mean-field (d = 3, n = 3) and 3D-Heisenberg (d = 3, n = 3) model for SmNi3 and SmNi2.2Fe0.8, respectively.
Cooman, TravonTrejos, TatianaRomero, Aldo H.Arroyo, Luis E....
10页
查看更多>>摘要：Portable Raman instruments provide quick, nondestructive analysis of organic and inorganic compounds, making it widely applicable in various disciplines. However, the instrument's accuracy when analyzing pure, or multiple component mixtures is still an aspect that needs improvement. This study explored machine learning algorithms to classify single compounds, binary, ternary, and quaternary mixtures by the compound name, and the com-pound's class, using seized drugs and common diluents as a model. The accuracies were >= 93% for most pure, binary mixtures, and quaternary mixtures algorithms. Therefore, incorporating machine learning algorithms in portable instruments, can improve the detection of unknown substances with high accuracies.
查看更多>>摘要：Due to the high activity, MoS2 is promising in replacing Pt-based electrocatalysts in hydrogen evolution reaction (HER) applications. However, the poor conductivity and fewer activity sites of 2H-MoS2 impede its practical application. The overall performance of 1 T'-MoS2 still has gaps to those Pt-based electrocatalysts. Thus, in this work, methods of doping and introducing defects were attempted to further improve the HER performance of 1 T'-MoS2. Through first-principle methods, the mechanism of HER on 1 T'-MoS2 with dopants or defects was analyzed. We found that Ni doping can further optimize the HER performance of 1 T'-MoS2.
查看更多>>摘要：Two ultraviolet photons (250-282 nm) excited atomic bromine, Br(4p(5) 2P(J); J = 1/2, 3/2), to the terms built from the 4p(4)5p electronic configuration. Through visible and infrared (VIS-IR) transitions and/or collisions with ambient gases, the terms transfer to the (2,4)DJ and( 2,4)PJ states in the 4p44d and 4p45s electronic configurations. The vacuum ultraviolet (VUV) emission (125-163 nm) from the 4p(4)4d and 4p(4)5s states to the 4p(5 2)P(J) state was detected. Twenty in 25 allowed two-photon transitions were observed; however, no VUV or VIS-IR emission from the other five transitions was detected. The findings differ from those by the previous reports on the two-photon resonance-enhanced ionization.
查看更多>>摘要：Three different adsorption states of iron on SC were proposed to compare their catalytic reduction capabilities for NO. Through reaction path analysis, it was found that the decomposition of N2O is barrierless. Moreover, through the thermodynamic and kinetic analysis to compare the reaction activation energy and the reaction rate constant, we concluded that the catalytic reduction effect of NO when iron atom adsorbed on SC (especially in the monovacancy SC) in a bonded form is better than that when iron atom adsorbed on SC in a non-bonded form.
查看更多>>摘要：Macromolecular catholyte materials store multiple positive charges in all-organic redox flow cells. Presently, little is known about the electronic structure and chemical stability of these macromolecules in different states of charge. Here we demonstrate that in propeller-like catholyte trimers (tripods), chemical stability increases when they become fully charged.
查看更多>>摘要：High-quality epitaxial LaNiO3 films have been grown on (001)-oriented SrTiO3 substrate with Sr3Al2O6 buffer layer by pulsed laser deposition. Different from traditional LaNiO3 metallic behavior, LaNiO3/Sr(3)Al2O(6) films exhibit semi-conductor behavior. In-plane lattice parameters of the LaNiO3 films are changed by in-plane strain from Sr(3)Al2O(6). The valence state of Ni in the film is related to in-plane strain. Ni3+ is the dominant factor for LaNiO(3 )films to maintain metallic behavior. Meanwhile, with the thickness of LaNiO3 increasing, the resistivity of LaNiO3/Sr3Al2O6 films can be adjusted. Conductive mechanism of LaNiO3 and all LaNiO3/Sr(3)Al(2)O(6 )films can be attributed to different Ni3+/Ni2+ ratios.
NSTL
Elsevier