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991.
《Applied Mathematical Modelling》2014,38(7-8):2037-2050
The elevator system driven by a permanent magnet synchronous motor (PMSM) is studied in this paper. The mathematical model of the elevator system includes the electrical and mechanical equations, and the dimensionless forms are derived for the purpose of practicable upward and downward movement. In this paper, the trapezoidal, cycloidal, five-degree (5-D) and seven-degree (7-D) polynomial and industry trajectories are designed and compared numerically in various motion and the absolute input energies. From numerical simulations, it is found that the trapezoidal trajectory consumes the minimum energy; the 7-D polynomial trajectory consumes the maximum one. The less end-point constraints are required, the less energy is consumed. Finally, the proposed sliding mode controller (SMC) is employed to demonstrate the robustness and well tracking control performance numerically. 相似文献
992.
Patricia A. Evans 《Journal of Discrete Algorithms》2011,9(4):335-343
This paper presents the first polynomial time algorithm for finding common RNA substructures that include pseudoknots and similar structures. While a more general problem is known to be NP-hard, this algorithm exploits special features of RNA structures to match RNA bonds correctly in polynomial time. Although the theoretical upper bound on the algorithm?s time and space usage is high, the data-driven nature of its computation enables it to avoid computing unnecessary cases, dramatically reducing the actual running time. The algorithm works well in practice, and has been tested on sample RNA structures that include pseudoknots and pseudoknot-like tertiary structures. 相似文献
993.
The generation process of silver chloride was studied using dynamic speckle methods including speckle size measurement and speckle contrast measurement. The quantity and size changes of the sedimentation particles in the illuminating region were investigated and analyzed. 相似文献
994.
995.
The use of a fiber Bragg grating (FBG) sensor array for the measurement of dynamic combined stress of ship thruster inner-skin is presented. The triaxial stress is detected using improved three-element rectangular rosette consisting of FBG sensors. Phase lag effect among triaxial stress sensor is considered and eliminated by employing multi-channel demodulation and improving the layout of sensor rosette array and connection layout. The tests are carried on to measure the distributed combined-stress change of ship thruster duct when ship thruster work at different rotate speed and pitch of angle. The test result are analyzed which show that measured stress are acceptable and in accord with predicted result. 相似文献
996.
A dark soliton pulse beam that has potential applications in the probing and transport of atoms or molecules as an optical tweezers is demonstrated. The trapped pulse beam is formed in the gap between a BP signal at 1500.00 nm and Stokes signal at 1500.09 nm, which has peak powers of −12 dBm. The generated beam is seen to be stable with no fluctuations over a test period of 10 min, which is important to ensure that the transported atom/molecule is not lost in the link media, therefore, the dynamic optical tweezers are now plausible. The theoretical background of the trapped atom/molecule is also analyzed and described in details. The atomic/molecular network via a wavelength router is also described. 相似文献
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998.
Cascade lipase-catalyzed lactonization has been applied to dynamic hemithioacetal formation, leading to efficient five- and six-membered lactone synthesis as well as chiral discrimination. Solvent-dependent regioselectivity was observed for the selective formation of 1,3-oxathiolan-5-one and γ-butyrolactone derivatives. 相似文献
999.
Yueyue Liu Xiangqian Wang Hongkang Xie Hongmei Feng Xiaolei Li Huiliang Wu Zengtai Zhu Yi Huang Wenshu Liu Genliang Han Jianbo Wang Qingfang Liu 《Physics letters. A》2019,383(34):125986
The effect of bilayer repeats (N) on the static and dynamic magnetic properties of Co/Ni multilayers was investigated. The effective perpendicular magnetic anisotropy constant of multilayers drops from erg/cm3 to erg/cm3 with N increasing from 5 to 11. For Co/Ni multilayers with , sharp magnetization switching was observed. In contrast, Co/Ni multilayers with have a long tail in the hysteresis loop. Ferromagnetic resonance measurements show that intrinsic Gilbert damping changes from 0.021 to 0.016 with increase in N and is inversely proportional to N. This study provides a deep understanding and effective control of magnetic properties of Co/Ni multilayers for spintronics devices. 相似文献
1000.