1,348 research outputs found

    N′-(4-Fluoro­benzyl­idene)acetohydrazide

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    The title compound, C9H9FN2O, was prepared by the reaction of 4-fluoro­benzophenone and acethydrazide. In the mol­ecule, all non-H atoms are essentially coplanar [r.m.s. deviation = 0.065 (2) Å]. In the crystal, mol­ecules are linked into centrosymmetric dimers by pairs of inter­molecular N—H⋯O hydrogen bonds

    N′-[1-(4-Chloro­phen­yl)ethyl­idene]acetohydrazide

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    In the title compound, C10H11ClN2O, the dihedral angle between the acetohydrazide group and the aromatic ring is 33.76 (9)°. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops

    Crossing at a Red Light: Behavior of Cyclists at Urban Intersections

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    To investigate the relationship between cyclist violation and waiting duration, the red-light running behavior of nonmotorized vehicles is examined at signalized intersections. Violation waiting duration is collected by video cameras and it is assigned as censored and uncensored data to distinguish between normal crossing and red-light running. A proportional hazard-based duration model is introduced, and variables revealing personal characteristics and traffic conditions are used to describe the effects of internal and external factors. Empirical results show that the red-light running behavior of cyclist is time dependent. Cyclist’s violating behavior represents positive duration dependence, that the longer the waiting time elapsed, the more likely cyclists would end the wait soon. About 32% of cyclists are at high risk of violation and low waiting time to cross the intersections. About 15% of all the cyclists are generally nonrisk takers who can obey the traffic rules after waiting for 95 seconds. The human factors and external environment play an important role in cyclists’ violation behavior. Minimizing the effects of unfavorable condition in traffic planning and designing may be an effective measure to enhance traffic safety

    Interlayer Interactions in Anisotropic Atomically-thin Rhenium Diselenide

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    Recently, two-dimensional (2D) materials with strong in-plane anisotropic properties such as black phosphorus have demonstrated great potential for developing new devices that can take advantage of its reduced lattice symmetry with potential applications in electronics, optoelectronics and thermoelectrics. However, the selection of 2D material with strong in-plane anisotropy has so far been very limited and only sporadic studies have been devoted to transition metal dichalcogenides (TMDC) materials with reduced lattice symmetry, which is yet to convey the full picture of their optical and phonon properties, and the anisotropy in their interlayer interactions. Here, we study the anisotropic interlayer interactions in an important TMDC 2D material with reduced in-plane symmetry - atomically thin rhenium diselenide (ReSe2) - by investigating its ultralow frequency interlayer phonon vibration modes, the layer dependent optical bandgap, and the anisotropic photoluminescence (PL) spectra for the first time. The ultralow frequency interlayer Raman spectra combined with the first study of polarization-resolved high frequency Raman spectra in mono- and bi-layer ReSe2 allows deterministic identification of its layer number and crystal orientation. PL measurements show anisotropic optical emission intensity with bandgap increasing from 1.26 eV in the bulk to 1.32 eV in monolayer, consistent with the theoretical results based on first-principle calculations. The study of the layer-number dependence of the Raman modes and the PL spectra reveals the relatively weak van der Waals interaction and 2D quantum confinement in atomically-thin ReSe2.Comment: 17 pages, 5 figures, supplementary informatio

    3-(4-Methoxy­phen­yl)-1-(2-nitrophen­yl)prop-2-en-1-one

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    The title compound, C16H13NO4, was prepared from 2-nitrylhypnone [systematic name: 1-(2-nitrophenyl)ethanone] and 4-methoxy­benzophenone by a Claisen–Schmidt condensation. The dihedral angle formed by the two benzene rings is 80.73 (2). The crystal packing is stabilized by inter­molecular C—H⋯O hydrogen bonds
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