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71.
Nonlinear Dynamics - The self-excitation of spring–mass system subjected to dry friction has been studied for decades because of its interesting and complex nonlinear dynamics behaviors. In... 相似文献
72.
Dr. Yaru Gong Chao Qin Yuteng Zhang Prof. Chunyi Sun Prof. Qinhe Pan Xinlong Wang Zhongmin Su 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22218-22222
Systematic design and self-assembly of metal–organic polyhedra with predictable configurations has been a long-standing challenge in crystal engineering. Herein a concave polyoxovanadate cluster, [V6O6(OCH3)9(SO4)4]5−, which can be generated in situ under specific reaction conditions, is reported. Based on this cluster, a potential trivalent molecular building block, [V6O6(OCH3)9(SO4)(CO2)3]2−, can be obtained by the bridging-ligand-substitution strategy and it possesses appropriate angle information for the design of molecular cubes. Utilizing the face-directed assembly of the trivalent molecular building block and a diverse set of tetratopic carboxylate linkers, a series of metal–organic cubes ( VMOC-1 – VMOC-5 ) with the same topology but different functionalities and dimensions were designed and constructed. An inclusion study using VMOC-3 shows that they are potential molecular receptors for selective capture of size-matching polycyclic aromatic hydrocarbon guest molecules. 相似文献
73.
74.
I. P. Studenyak M. Kranjcec L. M. Suslikov D. Sh. Kovacs V. V. Pan’ko 《Optics and Spectroscopy》2002,92(4):532-535
The absorption edge in Cu6P(S1?x Sex)5Br crystals has been studied for strong absorption in the temperature range of 77–330 K. The parameters of the Urbach absorption edge and exciton-phonon interactions in Cu6P(S1-x Sex)5Br crystals are determined and their effect on the composition disorder is studied. 相似文献
75.
In this article we first study an equivariant cyclic cohomology for weak H-module agebras over a weak Hopf algebra H with a bijective antipode. Then we define an equivariant K-theory for weak quantum Yetter–Drinfeld algebras over H and establish a generalized Connes' pairing between the equivariant cyclic cohomology and the equivariant K-theory. As an application we consider our theory for groupoids. 相似文献
76.
Ping Ding Xinhua Pan Zhizhen Ye Haiping He Honghai Zhang Wei Chen Chongyu Zhu Jingyun Huang 《Applied Physics A: Materials Science & Processing》2013,112(4):1051-1055
High-quality ZnO thin films were grown on a-plane sapphire substrates by plasma-assisted molecular beam epitaxy. X-ray diffraction and transmission electron microscopy reveal that the ZnO films have high structural quality and an atomically sharp ZnO/Al2O3 interface. The full width at half maximum values of the 0002 and $30\bar{3}2$ ZnO ω-rocking curves are 467.8 and 813.5 arc sec for a 600 nm thick ZnO film. A screw dislocation density of 4.35×108 cm?2 and an edge dislocation density of 3.38×109 cm?2 are estimated by X-ray diffraction. The surface of the ZnO epilayers contains hexagonal pits, which can be observed in the Zn-polar ZnO. The films have a resistivity of 0.119 Ω?cm, an electron concentration of 6.85×1017 cm?3, and a mobility of 76.5 cm2?V?1?s?1 at room temperature. Low temperature photoluminescence measurements show good optical properties comparable to ZnO single crystals. 相似文献
77.
Fangyuan Meng Hongyan Yu Xuliang Zhou Yajie Li Mengqi Wang Wenyu Yang Weixi Chen Yejin Zhang Jiaoqing Pan 《中国光学快报(英文版)》2021,(4):67-70
Gas sensing for measurement of gas components, concentrations, and other parameters plays an important role in many fields. In this Letter, a micro-ring resonator laser used for gas sensing is experimentally demonstrated. The multi-quantumwells micro-ring laser based on whispering-gallery modes with an annular resonator and an output waveguide was fabricated. A single-mode laser with a wavelength of 1746.4 nm was fabricated for the first time, to the best of our knowledge,experimentally. The output power of 1.65 m W under 40 m A injection current was obtained with a side-mode suppression ratio over 33 d B. 相似文献
78.
This paper presents a new parameter and state estimation algorithm for single-input single-output systems based on canonical state space models from the given input–output data. Difficulties of identification for state space models lie in that there exist unknown noise terms in the formation vector and unknown state variables. By means of the hierarchical identification principle, those noise terms in the information vector are replaced with the estimated residuals and a new least squares algorithm is proposed for parameter estimation and the system states are computed by using the estimated parameters. Finally, an example is provided. 相似文献
79.
Ping-qi Pan 《计算数学(英文版)》1999,17(3):233-242
1.IntroductionThedualsimplexalgorithm[1,91andtheprimal-dualsimplealgorithm[6]arewellknownandefficientsimplexvariants.However,bothofthemneedaninitialdualfeasiblebasistogetstarted,andthereforecannotbedirectlyappliedtosolvingproblemsthatdonothavesuchane... 相似文献
80.
Hong Shi Qianwei Zhang Wenbing Xu Meinan Liu Jiashuang Pan Jie Yuan Kaijie Yang 《Entropy (Basel, Switzerland)》2022,24(8)
Polar cruise ships are exposed to extreme external conditions during voyages, resulting in cockpit windscreens that are prone to fogging and frosting, seriously affecting the driver’s vision and even threatening navigation safety. However, the current research mainly focuses on cabin comfort, ignoring the coupling of defogging and comfort. Accordingly, this paper combines cockpit-windshield-defogging design and cockpit comfort considerations, and proposes 108 orthogonal-ventilation design parameters based on the four basic ventilation methods. The effects of different air supply parameters on comfort and anti-fog characteristics are investigated by using fluid dynamics simulation methods. The entropy weight–TOPSIS algorithm is employed to find the optimal ventilation parameters. The results show that the “Down-supply up-return type vertical jet” air supply method corresponding to an air supply velocity of 1 m/s, an air supply temperature of 297 K, and an air supply relative humidity of 30% has the smallest Euclidean distance from the positive ideal solution, and the largest Euclidean distance from the negative ideal solution; thus, it obtains a higher and the highest priority. This air supply method provides the best thermal comfort for the drivers, as well as the best anti-fogging and defogging effect. The results can be useful to provide suggestions for the future design of the air-conditioning systems in polar cruise ships. 相似文献