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61.
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A stochastic model is developed describing a service system subject to inhomogeneous Poisson interruptions with age dependent interruption periods. By studying the probabilistic flow of the underlying multivariate Markov process, the Laplace transform of the effective service time is explicitly obtained. For general renewal interruptions, only the expected effective service time is derived. As an application, an optimal checkpoint policy is examined for database management. It is shown that an optimal policy maximizing the ergodic availability of the database is to implement a checkpoint as soon as the cumulative uptime of the database reaches a prespecified constantk
*. A computational procedure is then developed for findingk
* and numerical results are exhibited.This work was supported in part by the National Science Foundation under Grant No. ECS-8600992 and by the IBM Program of Support for Education in the Management of Information Systems. 相似文献
63.
M. Tsutsumi 《偏微分方程通讯》2013,38(6-7):885-907
We consider the initial–boundary value problem for the nonlinear Schr‐dinger equations in an exterior domain. Global existence theorem of smooth solutions is established by using a–priori decay estimates of solutions which are obtained by the pseudoconformal indentity 相似文献
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66.
Takashi Ishizu Hiroyuki Tsutsumi Hideji Yamamoto Kazunobu Harano 《Magnetic resonance in chemistry : MRC》2009,47(4):283-287
The structure of inclusion complexes of γ‐cyclodextrin (γ‐CD), (–)‐gallocatechin gallate (GCg), and (–)‐epigallocatechin gallate (EGCg) in D2O was investigated using several NMR techniques. GCg formed a 1:1 inclusion complex with γ‐CD in which the A and C rings of GCg were inserted deep at the head of the A ring into the γ‐CD cavity from the wide secondary hydroxyl group side. In the 1:1 inclusion complex with GCg and γ‐CD, the GCg moiety maintained a conformation in which the B and B′ rings of GCg took both pseudoequatorial positions with respect to the C ring. The structure of the inclusion complex of GCg and γ‐CD obtained from NMR experiments supported well that determined from PM6 semiempirical SCF MO calculations. However, 1H NMR experiments suggested that EGCg did not form any inclusion complex with γ‐CD in D2O. The marked difference between GCg and EGCg in inclusion behavior toward γ‐CD may be explained in terms of the stabilization energy calculated with the PM6 method. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Ayumi Ishii Shinobu Kishi Hideki Ohtsu Toshifumi Iimori Takakazu Nakabayashi Nobuhiro Ohta Naoto Tamai Milan Melnik Miki Hasegawa Yuzo Shigesato 《Chemphyschem》2007,8(9):1345-1351
The electronic and structural behaviour of a Pr(III) complex with 4,7-diphenyl-1,10-phenanthroline, [Pr(bathophen)(2)(NO(3))(3)], is investigated with respect to the effect of configuration changes on the Pr(III) centre. [Pr(bathophen)(2)(NO(3))(3)] luminesces from the excited states of the ligand and the metal ion. The fluorescence, ff-emission ((1)D(2)-->(3)H(4)), and phosphorescence bands appear at 394, 608.2 and 482 nm, respectively, in the solid state. In acetonitrile, the complex also shows multiple emissions. From the time-resolved emission and the lifetime measurements, the excitation energy-transfer in [Pr(bathophen)(2)(NO(3))(3)] is clarified, that is, the upper excited triplet level of the ligand acts as an energy donor, while the (1)D(2) levels of Pr(III) is the acceptor. Additionally, the emission phenomena of the complex can be modified by molecular distortion, particularly by rotation of the phenyl groups in the ligand. 相似文献
69.
Kun‐Heng Chiang Shi‐Han Lu Wan‐Ping Yen Naoto Uramaru Wei‐Siou Tseng Te‐Wei Chang Fung Fuh Wong 《Heteroatom Chemistry》2016,27(4):235-242
A convenient synthetic method for N‐arylformamide derivatives was successfully developed by reacting α‐iodo‐N‐arylacetamides with formamide. This method was applicable to α‐iodo‐N‐arylacetamide substrates bearing electron‐donating or electron‐withdrawing groups, N‐(benzo[d][1,3]dioxol‐5‐yl)‐2‐iodoacetamide, 2‐iodo‐N‐(pyridin‐2‐yl)acetamide, and 2‐iodo‐N‐(naphthalen‐4‐yl)acetamide to give the corresponding N‐arylformamides in moderate to excellent yields (65–94%). A plausible mechanism was proposed to account for the new transformation. 相似文献
70.
Takahiro Matsumoto Seikou Nakamura Naoto Kojima Tomohiro Hasei Masayuki Yamashita Tetsushi Watanabe Hisashi Matsuda 《Tetrahedron letters》2017,58(36):3574-3578
From the methanolic extract of the aerial parts of Isodon japonicus, two new ent-kaurane diterpenes, isodonterpenes I and II, were isolated together with 10 known diterpenes. Their chemical structures were elucidated on the basis of chemical and physicochemical evidence. The absolute configuration of isodonterpene I was elucidated by Cu-Kα X-ray crystallographic analysis. Antimutagenic activities of the major diterpenes were evaluated by the Ames test. This study represents the first evaluation of the antimutagenic activities of ent-kaurane diterpenes. 相似文献