74,397 research outputs found

    Understanding of the Retarded Oxidation Effects in Silicon Nanostructures

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    In-depth understanding of the retarded oxidation phenomenon observed during the oxidation of silicon nanostructures is proposed. The wet thermal oxidation of various silicon nanostructures such as nanobeams, concave/convex nanorings and nanowires exhibits an extremely different and complex behavior. Such effects have been investigated by the modeling of the mechanical stress generated during the oxidation process explaining the retarded regime. The model describes the oxidation kinetics of silicon nanowires down to a few nanometers while predicting reasonable and physical stress levels at the Si/SiO2_{2} interface by correctly taking into account the relaxation effects in silicon oxide through plastic flow

    Macroscopical Entangled Coherent State Generator in V configuration atom system

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    In this paper, we propose a scheme to produce pure and macroscopical entangled coherent state. When a three-level ''V'' configuration atom interacts with a doubly reasonant cavity, under the strong classical driven condition, entangled coherent state can be generated from vacuum fields. An analytical solution for this system under the presence of cavity losses is also given

    Relaxing the Irrevocability Requirement for Online Graph Algorithms

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    Online graph problems are considered in models where the irrevocability requirement is relaxed. Motivated by practical examples where, for example, there is a cost associated with building a facility and no extra cost associated with doing it later, we consider the Late Accept model, where a request can be accepted at a later point, but any acceptance is irrevocable. Similarly, we also consider a Late Reject model, where an accepted request can later be rejected, but any rejection is irrevocable (this is sometimes called preemption). Finally, we consider the Late Accept/Reject model, where late accepts and rejects are both allowed, but any late reject is irrevocable. For Independent Set, the Late Accept/Reject model is necessary to obtain a constant competitive ratio, but for Vertex Cover the Late Accept model is sufficient and for Minimum Spanning Forest the Late Reject model is sufficient. The Matching problem has a competitive ratio of 2, but in the Late Accept/Reject model, its competitive ratio is 3/2

    Simultaneously continuous retraction and Bishop-Phelps-Bollob\'as type theorem

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    We study the existence of a retraction from the dual space XX^* of a (real or complex) Banach space XX onto its unit ball BXB_{X^*} which is uniformly continuous in norm topology and continuous in weak-* topology. Such a retraction is called a uniformly simultaneously continuous retraction. It is shown that if XX has a normalized unconditional Schauder basis with unconditional basis constant 1 and XX^* is uniformly monotone, then a uniformly simultaneously continuous retraction from XX^* onto BXB_{X^*} exists. It is also shown that if {Xi}\{X_i\} is a family of separable Banach spaces whose duals are uniformly convex with moduli of convexity δi(ε)\delta_i(\varepsilon) such that infiδi(ε)>0\inf_i \delta_i(\varepsilon)>0 and X=[Xi]c0X= \left[\bigoplus X_i\right]_{c_0} or X=[Xi]pX=\left[\bigoplus X_i\right]_{\ell_p} for 1p<1\le p<\infty, then a uniformly simultaneously continuous retraction exists from XX^* onto BXB_{X^*}. The relation between the existence of a uniformly simultaneously continuous retraction and the Bishsop-Phelps-Bollob\'as property for operators is investigated and it is proved that the existence of a uniformly simultaneously continuous retraction from XX^* onto its unit ball implies that a pair (X,C0(K))(X, C_0(K)) has the Bishop-Phelps-Bollob\'as property for every locally compact Hausdorff spaces KK. As a corollary, we prove that (C0(S),C0(K))(C_0(S), C_0(K)) has the Bishop-Phelps-Bollob\'as property if C0(S)C_0(S) and C0(K)C_0(K) are the spaces of all real-valued continuous functions vanishing at infinity on locally compact metric space SS and locally compact Hausdorff space KK respectively.Comment: 15 page
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