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1.
Banach空间上的框架与Riesz基 总被引:5,自引:0,他引:5
本文讨论Banach空间上框架、无冗框架与Riesz基之间的关系及它们的稳定性. 相似文献
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电磁继电器触点参数的测试 总被引:1,自引:0,他引:1
本文介绍了电磁继电器触点电参数的测试方法,包括接触电阻、绝缘电阻参数测试。 相似文献
4.
ATM技术是ITU-T推荐的B-ISDN交换技术,而帧中继在提供广域网业务方面很成功。因此,在ATM发展的初期不可避免地会与帧中继技术并存。本文阐述了ATM与帧中继网络互加和业务互连的相关技术及其存在的问题。 相似文献
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Hong Oh Kim Rae Young Kim Jae Kun Lim Zuowei Shen 《Journal of Approximation Theory》2007,147(2):196-204
We start with a characterization of a pair of frames to be orthogonal in a shift-invariant space and then give a simple construction of a pair of orthogonal shift-invariant frames. This is applied to obtain a construction of a pair of Gabor orthogonal frames as an example. This is also developed further to obtain constructions of a pair of orthogonal wavelet frames. 相似文献
7.
《Digital Communications & Networks》2023,9(1):90-100
In Energy Harvesting Wireless Sensor Networks (EHWSN), the communication protocol will directly affect the final performance of the network, so it is necessary to study the communication protocol based on EHWSN. In this paper, for the low-cost fixed clustering problem, a fixed clustering protocol RRCEH is based on random relaying. Our proposed RRCEH abandons the inefficient inter-cluster communication method of the traditional fixed clustering protocol. To coordinate the data upload of the cluster head, RRCEH allocates different random relay vectors to each ring area of the network, and combines all the random relay vectors into a random relay matrix of RRCEH. In each communication round, the cluster head node randomly selects its relay target node to send data according to the probability distribution in the random relay vector in the area. For two different cluster head configuration scenarios, by optimizing the random relay matrix, RRCEH can effectively reduce the network's configuration requirements for cluster head energy harvesting capability, thus reducing the deployment cost of EHWSN. 相似文献
8.
Density functional theory calculations were carried out for the title reactions. Ethylene oxide and methylamine were adopted as reactants. Amine clusters (dimer, trimer, tetramer, and pentamer) were considered, because the combination of one oxide and one amine molecule gave a large activation energy. An amine tetramer was found to react favorably with the oxide via various zwitterionic intermediates. A back-side S(N)2 nucleophilic attack of one amine and the subsequent proton relay up to the front side provide a stabilized reaction field. The amine-alcohol mixed reactant may react readily with the oxide, because the alcoholic O-H group is in contact with the oxide oxygen with the strong hydrogen-bond stabilization. 相似文献
9.
Zhang‐Jun Guan Wei‐Jiong Zhang Xi‐Lang Zhou 《International Journal of Communication Systems》2012,25(11):1505-1512
The performance of multi‐antenna relay communication systems is investigated in this letter. The source broadcasts the signal to all the relays and the destination. Decode‐and‐forward scheme is adopted at the relays, and the destination employs maximum ratio combining (MRC) technique to maximize the received signal‐to‐noise ratio. Closed‐form expressions of outage probability are derived in the MRC case and minimum routes MRC case. An adaptive grouping algorithm of relay antennas is also presented under the constraint of total antenna number. Simulation results show that the analytical curves agree with the simulated ones very well, and the performance of the proposed grouping algorithm is very close to the upper bound mentioned in other papers. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
Dr. Qianjia Yuan Prof. Matthew S. Sigman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10823-10827
In this report, a palladium-catalyzed redox-relay Heck process to access optically active alkenylated α,β-unsaturated lactams is described. Under mild reaction conditions, electron-deficient alkenyl triflates and electron-rich alkenyl iodonium salts undergo enantioselective and site-selective coupling with enelactams to deliver the products in high yields and excellent enantioselectivities. Furthermore, the products allow facile access to natural products such as (+)-calvine and (+)-2-epicalvine in addition to the bioactive molecule aza-goniothalamin. 相似文献