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An explicit expression of the Wigner operator is derived, such that the Wigner function of a quantum state is equal to the expectation value of this operator with respect to the same state. This Wigner operator leads to a representation-independent procedure for establishing the correspondence between the inhomogeneous symplectic group applicable to linear canonical transformations in classical mechanics and the Weyl-metaplectic group governing the symmetry of unitary transformations in quantum mechanics. 相似文献
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The nonlinear propagation problem of optical beams in media with an intensity dependent indices of refraction is solved in the case of a fundamental gaussian beam. This solution is made possible by assuming everywhere along the propagation path a quadratic index profile. The quadratic constant is obtained self-consistently from the second term in a Taylor expansion of the local gaussian intensity. The solution constitutes an extension of the well known ABCD formalism to nonlinear propagation. 相似文献
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This research proposes a newly developed stray light filter in order to eliminate stray light, which otherwise might severely reduce the performance of the con-focal microscopy presented in this research. First, an optical design for con-focal microscopy with a digital micro-mirror device (DMD) is illustrated; second, a newly developed stray light filter is presented, which functions to eliminate possible stray light and ghost images without any sacrifice of luminance. It indicates that not only can the optical system be much simplified but also that its resolution could be one step higher, because the system employs neither a pinhole nor a CCD camera lens. Experimental results are shown in the paper, demonstrating an increase in contrast of up to 60%. 相似文献
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Effects of substituent and solvent on the structure and spectral properties of maleimide derivatives
Chin-Kuen Tai Yih-Jiun Lin Pao-Ling Yeh Yi-Ren Tzeng Yu-Ma Chou Bo-Cheng Wang 《Journal of Molecular Structure》2008,860(1-3):58-63
The maximum absorption wavelength , emission wavelength (λem) and the related oscillator strength (f) of the maleimides in the ground and first excited states were calculated by using the DFT, CIS and the time-dependent density functional theory (TD-DFT) methods, where the molecular structures were optimized by DFT/B3LYP/6-31G* calculation. Solvent effects on the maleimides were examined using the PCM simulation at DFT/B3LYP level with the 6-31G* basis set. For N-substituted maleimide, the substituent gives only a slight influence on the maleimide chromophore, while planar conformation of PhMLH leads to the improvement in π-delocalization from substituent to maleimide unit. For 3,4-substituted maleimide, the steric repulsion between substituent and maleimide chromophore influences the extent of π-delocalization and the molecular conformation. The calculated and λem of maleimides are in good agreement with the experimental data. In the gas phase, both absorption and emission peaks are red-shift as compared to the non-substituted maleimide. Under solvent environment, the more planar conformation of PhMLH shows a blue-shift in the calculated and λem as compared with other N-substituted maleimides. For 3,4-substituted maleimides, the effect of substitution produces the most significant spectral red-shift as compared to other maleimides. 相似文献
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Reflection of an obliquely incident solitary wave onto a vertical wall is studied analytically and experimentally. We use the Kadomtsev-Petviashivili (KP) equation to analyze the evolution and its asymptotic state. Laboratory experiments are performed using the laser induced fluorescent (LIF) technique, and detailed features and amplifications at the wall are measured. Due to the lack of physical interpretation of the theory, the numerical results were previously thought not in good agreement with the theory. With proper treatment, we demonstrate that the KP theory provides an excellent model to predict the present laboratory results as well as the previous numerical results. The KP theory also indicates that the present laboratory apparatus is too short to achieve the asymptotic state. The laboratory and numerical results suggest that the maximum of the predicted four-fold amplification would be difficult to be realized in the real-fluid environment. The reality of this amplification remains obscure. 相似文献
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Chen C. Y. Kao C. L. Yeh H. C. Li H. T. Wu M. D. Cheng M. J. Li W. J. 《Chemistry of Natural Compounds》2022,58(3):385-386
Chemistry of Natural Compounds - A new ketone, vicamazone (4-(2-butoxyethoxy)-4-methylpentan-2-one) (1), was isolated from the leaves of Victoria amazonica (Nymphaeaceae). The structure of the new... 相似文献
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