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We propose and study a mutualism model with feedback controls. By applying a new differential inequality, we show that the conditions which ensure the permanence of the system are the same as that of the model without feedback controls, which means that the feedback control variables have no influence on the persistent property of the system. Our results not only improve but also complement some existing ones. 相似文献
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Qin Meng Guo-Ming Wang Jing Xue Bai-Feng Yang Huan He Guo-Yu Yang 《Journal of Cluster Science》2014,25(5):1319-1329
Two strontium borates Sr2[B6O9(OH)4] (1) and Sr2B5O9(OH)·H2O (2), with acentric structures have been synthesized under hydro/solvothermal conditions. Compound 1 is reported for the first time in the strontium borates system, and it crystallizes in the monoclinic space group P21 with unit cell parameters a = 6.8445(5) Å, b = 8.7033(6) Å, c = 8.4632(6) Å, β = 100.581(6)°, V = 495.58(6) Å3 and Z = 2. Its structure consists of unusual borate layers of 3, 11-membered rings, which are interconnected via Sr–O ionic bonds and hydrogen bonds to generate a 3D supramolecular network. Compound 2 is a known strontium borate, crystallizing in the monoclinic space group C 2 with a = 10.161 (13) Å, b = 7.965(4) Å, c = 6.393(11) Å, β = 128.0(2)°, V = 407.7(14) Å3 and Z = 2. Second-harmonic generation measurements on the powder samples reveal that 1 and 2 exhibits good SHG efficiency about 1.5 and 2 times that of KDP (KH2PO4) powder respectively. 相似文献
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It has been shown by Lei, in his recent paper, that there exists a large set of Kirkman triple systems of order uv (LKTS(uv)) if there exist an LKTS(v), a TKTS(v) and an LR(u), where a TKTS(v) is a transitive Kirkman triple system of order v, and an LR(u) is a new kind of design introduced by Lei. In this paper, we improve this product construction by removing the condition “there exists a TKTS(v)”. Our main idea is to use transitive resolvable idempotent symmetric quasigroups instead of TKTS. As an application, we can combine the known results on LKTS and LR-designs to obtain the existence of an LKTS(3nm(2·13n1+1)(2·13nt+1)) for n1, m{1,5,11,17,25,35,43,67,91,123}{22r+125s+1 : r0,s0}, t0 and ni1 (i=1,…,t). 相似文献
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V型原子与光场拉曼相互作用传送未知原子态 总被引:10,自引:0,他引:10
未知量子态从一个地方到另一个地方的隐形传送在量子信息领域中有非常重要的作用,提出了一种利用简并V型三能级原子与振幅很大的单模相干态腔场的拉曼相互作用来传送未知原子态的方案。 相似文献
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利用Raman型的Jaynes-Cummings模型传送光场的福克叠加态 总被引:9,自引:0,他引:9
提出了一种利用Λ型三能级原子与光场Raman相互作用来传送光场的福克叠加态的方案. 相似文献
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The concepts of k-systems, k-networks and k-covers were defined by A. Arhangel’skii in 1964, P. O’Meara in 1971 and R. McCoy, I. Ntantu in 1985, respectively. In this
paper the relationships among k-systems, k-networks and k-covers are further discussed and are established by mk-systems. As applications, some new characterizations of quotients or closed images of locally compact metric spaces are given
by means of mk-systems. 相似文献
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讨论Banach空间中算子级数的无条件收敛.分别在自反和含无条件基的条件下推广了Vcctor和Cary关于Hilbert空间的两个相应结果.即[1]的定理2和命题6.并且肯定回答了他们留下的问题. 相似文献