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21.
Fourier transform surface enhanced Raman spectrometer is used to characterize Ω-mercaptoalkanols (HO(CH2)nSH, n=2, 6) chemisorption on silver surface from their aqueous solution of different pH values. 相似文献
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Effect of acoustic resonance on the dynamic lift forces acting on two tandem cylinders in cross-flow
Direct measurements of the dynamic lift force acting on two tandem cylinders in cross-flow are performed in the presence and absence of acoustic resonance. The dynamic lift force is measured because it represents the integrated effect of the unsteady wake and therefore it is directly related to the dipole sound source generated by vortex shedding from the cylinder. Three spacing ratios inside the proximity interference region, L/D=1.75, 2.5 and 3 are considered. During the tests, the first transverse acoustic mode of the duct housing the cylinders is self-excited. In the absence of acoustic resonance, the measured dynamic lift coefficients agree with those reported in the literature. When the acoustic resonance is initiated, a drastic increase in the dynamic lift coefficient is observed, especially for the downstream cylinder. This can be associated with abrupt changes in the phase between the lift forces and the acoustic pressure. The dynamic lift forces on both cylinders are also decomposed into in-phase and out-of-phase components, with respect to the resonant sound pressure. The lift force components for the downstream cylinder are found to be dominant. Moreover, the out-of-phase component of the lift force on the downstream cylinder is found to become negative over two different ranges of flow velocity and to virtually vanish between these two ranges. Acoustic resonance of the first mode is therefore excited over two ranges of flow velocity separated by a non-resonant range near the velocity of frequency coincidence. It is therefore concluded that the occurrence of acoustic resonance is controlled by the out-of-phase lift component of the downstream cylinder, whereas the effect of the in-phase lift component is confined to causing small changes in the acoustic resonance frequency. 相似文献
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Measurements of the maximum transmittance of an in-plane switching liquid crystal display showed that it increases as rubbing angle is increased from 10 to 20°. This dependence was analysed in terms of the local variation of electric field intensity between electrodes, which in turn makes liquid crystal at various positions between the electrodes rotate to different angles. The local variation of electric field becomes prominent, especially in the case that the distance between the electrodes is much larger than the cell gap or electrode width. 相似文献
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The work function is an important material property with several applications in photonics and optoelectronics. We aimed to characterize the work function of clusters resulting from gold nanocrystals capped with oleylamine surfactant and drop-casted onto gold substrate. We used scanning Kelvin probe microscopy to investigate the work function, and complemented our study mainly with X-ray diffraction and X-ray photoelectron spectroscopy. The oleylamine works as an electron blocking layer through which the electrical conduction takes place by tunneling effect. The surface potential appears to depend on the size of the clusters, which can be ascribed to their difference in effective work function with the substrate. The charge state of gold clusters is discussed in comparison with theory, and their capacitance is calculated from a semi-analytical equation. The results suggest that at the nanoscale the work function is not an intrinsic property of a material but rather depends on the size and morphology of the clusters, including also effects of the surrounding materials. 相似文献
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In this paper,by use of the Schauder fixed-point theorem,the existence of solution of (k,n-k) Conjugate boundary value problems in Banach spaces is investigated. 相似文献
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Krzysztof Pomorski José M. Blanco Pavel V. Kostryukov Artur Dobrowolski Bo?ena Nerlo-Pomorska Micha? Warda Zhi-Gang Xiao Yong-Jing Chen Li-Le Liu Jun-Long Tian Xin-Yue Diao Qiang-Hua Wu 《中国物理C(英文版)》2021,45(5):054109-054109-11
Fission properties of the actinide nuclei are deduced from theoretical analysis. We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes. The results are compared with experimental data where available. The calculations were performed in the macroscopic-microscopic approximation with the Lublin-Strasbourg Drop (LSD) for the macroscopic part, and the microscopic energy corrections were evaluated in the Yukawa-folded potential. The Fourier nuclear shape parametrization is used to describe the nuclear shape, including the non-axial degree of freedom. The fission fragment mass yields of the nuclei considered are evaluated within a 3D collective model using the Born-Oppenheimer approximation. 相似文献