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41.
A new method is introduced to generate a elliptical hollow beam inside a cavity. Using a matrix eigenvalue method, the laser resonator with optical diffraction elements is theoretically analyzed and simulated. A elliptical hollow beam of good quality is realized experimentally. The interaction between linearly polarized elliptical hollow beam and a two-level atom is investigated theoretically. Although the linearly polarized elliptical hollow beam does not carry angular momentum, it can produce very high torque. The atoms initially at rest and located at off-beam- axis positions will rotate under the drive of the torque of the beam. The atomic motion trajectory in the field of elliptical hollow beam has been demonstrated. The study shows that the elliptical hollow beam might be a useful tool in the study of vortex property of Bose-Einstein condensate or ultra cold atom media. 相似文献
42.
给出了线和n-2的n阶(0,1)-矩阵的最大积和式的积分表达式,并证明了该积分表达式与[1]得到的组合表达式等价。 相似文献
43.
According to an induced-matter approach, Liu and Wesson obtained the rest mass of a typical particle from the reduction of a 5D Klein–Gordon equation to a 4D one. Introducing an extra-dimension momentum operator identified with the rest mass eigenvalue operator, we consider a way to generalize the 4D Dirac equation to 5D. An analogous normal Dirac equation is gained when the generalization reduces to 4D. We find the rest mass of a particle in curved space varies with spacetime coordinates and check this for the case of exact solitonic and cosmological solution of the 5D vacuum gravitational field equations. 相似文献
44.
45.
A nonlinear, compressible, non-isothermal gravity wave model that involves photochemistry is used to study the effects of gravity wave on atmospheric chemical species distributions in this paper. The changes in the distributions of oxygen compound and hydrogen compound density induced by gravity wave propagation are simulated. The results indicate that when a gravity wave propagates through a mesopause region, even if it does not break, it can influence the background distributions of chemical species. The effect of gravity wave on chemical species at night is larger than in daytime. 相似文献
46.
47.
Hongbo Zhang Rui Wang Kaixin Chen Han Yang Daming Zhang Maobin Yi Guoquan Wang Zhenchang Ma 《Optics & Laser Technology》2002,34(4):283-286
A new method, based on zero point of longitudinal electric field, was used to determine the spatial resolution of external electro-optic (EO) probing equipment. Considering the diffraction of Gauss beam, the result of external EO probing was simulated which was in accordance with the experiment. A spatial resolution <1 μm was demonstrated initially in our equipment using 650 nm laser diode as probe beam and semi-insulating GaP as probe tip. 相似文献
48.
Abstract. We propose a general approach to deal with nonlinear, nonconvex variational problems based on a reformulation of the problem
resulting in an optimization problem with linear cost functional and convex constraints. As a first step we explicitly explore
these ideas to some one-dimensional variational problems and obtain specific conclusions of an analytical and numerical nature. 相似文献
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50.
Ana Luísa Daniel‐da‐Silva João Carlos Moura Bordado José Miguel Martín‐Martínez 《Journal of Polymer Science.Polymer Physics》2007,45(22):3034-3045
The degree of phase separation in several moisture‐cured poly(urethane urea)s (PUUs) was studied by FTIR spectroscopy, wide angle X‐ray diffraction (WAXD), and temperature‐modulated differential scanning calorimetry (TMDSC). This latter technique was shown to be particularly useful in analysing the degree of phase separation in PUU polymers. Both phase mixing and phase segregation coexisted in the PUUs and the degree of phase separation increased as the urea hard segment (HS) content in the PUU increased. The maximum solubility of urea HSs into the polyol soft segments (SSs) was achieved for 50 wt % urea HS content in diol‐based PUUs, whereas for triol‐based PUUs the highest solubility between HS and SS was reached for lower urea HS amount. Finally, the higher the urea HS content the higher the extent of phase separation in the PUU. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3034–3045, 2007 相似文献