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101.
GENERATION OF NONLINEAR INTERNAL WAVES ON CONTINENTAL SHELF 总被引:4,自引:4,他引:0
Xu Zhao ting Yao Feng chao Wang Mei Physical Oceanography Laboratory Institute of Physical Oceanography Ocean University of Qingdao China Key Laboratory of Marine Science Numerical Modeling State Oceanic Administration Qingdao 《水动力学研究与进展(B辑)》2001,(3)
1 . INTRODUCTIONInternaltidalinteractionwithbottomfeaturesappearstobethedominantmechanismforgenera tionofthecoherentoceanicinternalwavesthatareobservablewithSAR ,closertoshore ,riverineorglacialintrusionandcontinentalbreakprovidesec ondarygeneratingmecha… 相似文献
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Young-Hwan You Won-Gi Jeon Jong-Ho Paik Dae-Ki Hong Hyoung-Kyu Song 《Broadcasting, IEEE Transactions on》2003,49(4):354-361
In this paper, an OFDM-CDMA system employing various diversity schemes is considered for a possible candidate of broadband wireless access networks and broadcasting applications. With an emphasis on a preamble design for multi-channel separation, we address a channel estimation based on the time-domain windowing and its imperfectness in OFDM-based multiple-antenna transmission systems. By properly designing each preamble for multiple antennas to be orthogonal in the time domain, the channel estimation can be applied to the HIPERLAN/2 and IEEE 802.11a standards in the case of more than two transmit antennas. Also, the effect of diversity techniques on the performance of OFDM-CDMA based broadband wireless access networks is investigated and the maximum achievable diversity gain for a two-path Rayleigh fading environment is evaluated. Simulation results show that the OFDM-CDMA system applying a space-time-frequency diversity with a full-rate full diversity code can give the diversity of D=4 and D=8 for both multi-user cases of maximum user and half user capacities, respectively. 相似文献
105.
M.H. Song B. Park S. Nishimura T. Toyooka I.J. Chung Y. Takanishi K. Ishikawa H. Takezoe 《Advanced functional materials》2006,16(14):1793-1798
A liquid crystal (LC) photonic device with an anisotropic optical heterojunction structure has been fabricated. The device has a phase‐retarding nematic LC (NLC) layer sandwiched between two polymer cholesteric LC films with right‐handed helices of different pitches. Electrotunable non‐reciprocal light transmittance and unidirectional circularly polarized (CP) lasing emission have been successfully demonstrated for this device structure. Two left CP (LCP) lasing emission peaks are observed at the edges of the overlapping region between the two photonic bands in the structure and are shifted upon the application of a voltage. In contrast, a non‐reciprocal right CP (RCP) lasing emission peak emerges at one of the band edges and diminishes upon the application of a voltage. These phenomena are interpreted based on the selective reflection of RCP light and the reorientation of the NLC molecules by the application of a voltage. 相似文献
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A very general model formulation is presented in the frequency domain for the pulse-echo ultrasonic response of an arbitrary scatterer in a fluid. The transducer is modeled as a piston source and the scatterer can be located anywhere in the transducer wavefield. The model is computationally efficient and is shown to agree well with initial experiments. 相似文献
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The entity-relationship (ER) model and its accompanying ER diagrams are widely used for database design and systems analysis. Many books and articles just provide a definition of each modeling component and give examples of the pre-built ER diagrams. As a result, beginners in data modeling have a great deal of difficulty learning how to approach a given problem, what questions to ask in order to build a model, what rules to use while constructing an ER diagram, and why one diagram is better than another. The authors present step-by-step guidelines, a set of decision rules proven to be useful in building ER diagrams, and a case study problem with a preferred answer as well as a set of incorrect diagrams for the problem. These guidelines and decision rules have been successfully used in their beginning database management system course 相似文献
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