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111.
Roberto Boada María ángeles Laguna‐Marco Jesús Chaboy 《Journal of synchrotron radiation》2009,16(1):38-42
An X‐ray magnetic circular dichroism (XMCD) study performed at the Ho L2,3‐edges in Ho6Fe23 as a function of temperature is presented. It is demonstrated that the anomalous temperature dependence of the Ho L2‐edge XMCD signal is due to the magnetic contribution of Fe atoms. By contrast, the Ho L3‐edge XMCD directly reflects the temperature dependence of the Ho magnetic moment. By combining the XMCD at both Ho L2‐ and L3‐edges, the possibility of determining the temperature dependence of the Fe magnetic moment is demonstrated. Then, both μHo(T) and μFe(T) have been determined by tuning only the absorption L‐edges of Ho. This result opens new possibilities of applying XMCD at these absorption edges to obtain quantitative element‐specific magnetic information that is not directly obtained by other experimental tools. 相似文献
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113.
Swimming microorganisms create flows that influence their mutual interactions and modify the rheology of their suspensions. While extensively studied theoretically, these flows have not been measured in detail around any freely-swimming microorganism. We report such measurements for the microphytes Volvox carteri and Chlamydomonas reinhardtii. The minute (~0.3%) density excess of V. carteri over water leads to a strongly dominant Stokeslet contribution, with the widely-assumed stresslet flow only a correction to the subleading source dipole term. This implies that suspensions of V. carteri have features similar to suspensions of sedimenting particles. The flow in the region around C. reinhardtii where significant hydrodynamic interaction is likely to occur differs qualitatively from a puller stresslet, and can be described by a simple three-Stokeslet model. 相似文献
114.
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116.
Marco Romito 《Probability Theory and Related Fields》2014,158(3-4):895-924
We consider the dyadic model with viscosity and additive Gaussian noise as a simplified version of the stochastic Navier–Stokes equations, with the purpose of studying uniqueness and emergence of singularities. We prove pathwise uniqueness and absence of blow-up in the intermediate intensity of the non-linearity, morally corresponding to the 3D case, and blow-up for stronger intensity. Moreover, blow-up happens with probability one for regular initial data. 相似文献
117.
Large part of combinatorial optimization research has been devoted to the study of exact methods leading to a number of very
diversified solution approaches. Some of those older frameworks can now be revisited in a metaheuristic perspective, as they
are quite general frameworks for dealing with optimization problems. In this work, we propose to investigate the possibility
of reinterpreting decompositions, with special emphasis on the related Benders and Lagrangean relaxation techniques. We show
how these techniques, whose heuristic effectiveness is already testified by a wide literature, can be framed as a “master
process that guides and modifies the operations of subordinate heuristics”, i.e., as metaheuristics. Obvious advantages arise
from these approaches, first of all the runtime evolution of both upper and lower bounds to the optimal solution cost, thus
yielding both a high-quality heuristic solution and a runtime quality certificate of that same solution. 相似文献
118.
Under a suitable condition on n and p, the quasilinear equation at critical growth −Δpu=λ|u|p−2u+|u|p∗−2u is shown to admit a nontrivial weak solution for any λ?λ1. Nonstandard linking structures, for the associated functional, are recognized. 相似文献
119.
We propose a realistic circuit QED experiment to test the extraction of past-future vacuum entanglement to a pair of superconducting qubits. The qubit P interacts with the quantum field along an open transmission line for an interval T_{on} and then, after a time-lapse T_{off}, the qubit F starts interacting for a time T_{on} in a symmetric fashion. After that, past-future quantum correlations will have transferred to the qubits, even if the qubits do not coexist at the same time. We show that this experiment can be realized with current technology and discuss its utility as a possible implementation of a quantum memory. 相似文献
120.
We show that symmetric block designs \({\mathcal {D}}=({\mathcal {P}},{\mathcal {B}})\) can be embedded in a suitable commutative group \({\mathfrak {G}}_{\mathcal {D}}\) in such a way that the sum of the elements in each block is zero, whereas the only Steiner triple systems with this property are the point-line designs of \({\mathrm {PG}}(d,2)\) and \({\mathrm {AG}}(d,3)\). In both cases, the blocks can be characterized as the only k-subsets of \(\mathcal {P}\) whose elements sum to zero. It follows that the group of automorphisms of any such design \(\mathcal {D}\) is the group of automorphisms of \({\mathfrak {G}}_\mathcal {D}\) that leave \(\mathcal {P}\) invariant. In some special cases, the group \({\mathfrak {G}}_\mathcal {D}\) can be determined uniquely by the parameters of \(\mathcal {D}\). For instance, if \(\mathcal {D}\) is a 2-\((v,k,\lambda )\) symmetric design of prime order p not dividing k, then \({\mathfrak {G}}_\mathcal {D}\) is (essentially) isomorphic to \(({\mathbb {Z}}/p{\mathbb {Z}})^{\frac{v-1}{2}}\), and the embedding of the design in the group can be described explicitly. Moreover, in this case, the blocks of \(\mathcal {B}\) can be characterized also as the v intersections of \(\mathcal {P}\) with v suitable hyperplanes of \(({\mathbb {Z}}/p{\mathbb {Z}})^{\frac{v-1}{2}}\). 相似文献