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A RhIII‐catalyzed C–H activation/cyclative capture approach, involving a nucleophilic addition of C(sp3)–Rh species to polarized double bonds is reported. This constitutes the first intermolecular catalytic method to directly access 1‐aminoindolines with a broad substituent scope under mild conditions.  相似文献   
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Organosilicon compounds have been extensively utilized both in industry and academia. Studies on the syntheses of diverse organosilanes is highly appealing. Through‐space metal/hydrogen shifts allow functionalization of C?H bonds at a remote site, which are otherwise difficult to achieve. However, until now, an aryl to alkyl 1,5‐palladium migration process seems to have not been presented. Reported herein is the remote olefination, arylation, and borylation of a methyl group on silicon to access diverse vinyl‐, benzyl‐, and borylsilanes, constituting a unique C(sp3)?H transformation based on a 1,5‐palladium migration process.  相似文献   
3.
In this paper, we give an alternative proof to the global existence result, which is originally owing to the pioneering work of Klainerman and Christodoulou, for the Cauchy problem of quasilinear wave equations with null condition in three space dimensions. The proof can display the following three features simultaneously: the Lorentz boost operator is not employed in the generalized energy estimates; the generalized energy of the solution will be always small, which was first observed by Alinhac; and the initial data are not assumed to have a compact support. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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在聚龙一号脉冲功率装置上首次完成了对带正弦扰动铝套筒Z箍缩的X射线背光照相实验。实验采用千焦耳激光器(1053 nm, 1 kJ, 1 ns)驱动固体靶材产生X射线, 然后利用基于球面晶体的单色背光照相技术以及直接点投影背光照相技术, 成功观测到约7.5 MA电流驱动条件下, Z箍缩铝套筒的外边界不稳定性发展情况。该实验验证了在聚龙一号装置上联合千焦耳激光器开展X射线背光照相实验的能力, 为后续精密Z箍缩物理研究奠定了基础。  相似文献   
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Diffusion on random systems above and at their percolation threshold in three dimensions is carried out by a molecular trajectory method and a simple lattice random walk method, respectively. The classical regimes of diffusion on percolation near the threshold are observed in our simulations by both methods. Our Monte Carlo simulations by the simple lattice random walk method give the conductivity exponent μ/ν=2.32±0.02 for diffusion on the incipient infinite clusters and μ/ν=2.21±0.03 for diffusion on a percolating lattice above the threshold. However, while diffusion is performed by the molecular trajectory algorithm either on the incipient infinite clusters or on a percolating lattice above the threshold, the result is found to be μ/ν=2.26±0.02. In addition, it takes less time step for diffusion based on the molecular trajectory algorithm to reach the asymptotic limit comparing with the simple lattice random walk.  相似文献   
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In this paper, we investigate the problem of synchronization for the time varying delayed complex dynamical networks via impulsive control method, several sufficient synchronization conditions are given, and we consider the impulsive control matrices are time varying delayed matrices. Furthermore, we found impulsive control does not always play an active role in synchronization although impulsive control strategy is cheaper and simpler than other control strategy. Finally, numerical simulations are also given to demonstrate the effectiveness of the proposed schemes.  相似文献   
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The problem of globally exponential stability of stochastic neutral-type delayed neural networks with impulsive perturbations and Markovian switching is studied in this paper. By using the Lyapunov?CKrasovskii method and the stochastic analysis approach, a sufficient condition to ensure globally exponential stability for the stochastic neutral-type delayed neural networks with impulsive perturbations and Markovian switching is derived. Finally, a numerical example is given to illustrate the effectiveness of the result proposed in this paper.  相似文献   
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Sijun Fan  Chunlei Yu  Dongbing He  Kefeng Li  Lili Hu 《Journal of Non》2011,357(11-13):2324-2327
Silver-doped Li, Na and K aluminophosphate glasses and the corresponding basic glasses were prepared by traditional melting–quenching method. The influence of alkali metal oxides on the dosimetric properties was investigated under conditions of the same dosage and fixed silver concentration. The energy dependence, sensitivity and build-up time are related to alkali metal oxides. The atomic number, ionic radius and field strength of alkali ions have important effect on these dosimetric properties. Li aluminophosphate glass possesses the lowest fluorescence response and energy dependence; Na aluminophosphate glass owns the shortest build-up time; K aluminophosphate glass has the strongest fluorescence response, longest build-up time and highest energy dependence.  相似文献   
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