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排序方式: 共有170条查询结果,搜索用时 187 毫秒
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Y.M. Jia S.W. Or K.H. Lam H.L.W. Chan Y.X. Tang X.Y. Zhao H.S. Luo 《Applied Physics A: Materials Science & Processing》2007,86(4):525-528
We report on the magnetoelectric (ME) effect in three-phase magnet-metal-cap-piezoceramic composites of a thickness-polarized
Pb(Zr,Ti)O3 disk bonded between two truncated conical brass caps and two thickness-magnetized NdFeB magnets along the thickness direction.
The effect originated from the product of the magnetic attractive–repellent effect in the magnets and the amplified piezoelectric
effect in the cap-disk assembly. The composites exhibited a ME voltage coefficient αV of ∼2.6 mV/Oe in the non-resonance frequency range of 0.1–10 kHz with good voltage-field linearity in the field range of
10-3–10 Oe, besides an enhanced αV of 167.4 mV/Oe at a resonance frequency of 14.4 kHz. Compared to conventional two-phase and three-phase magnetostrictive
material-contained ME composites, these composites possessed two distinct benefits of higher property-tailorable flexibility
and requiring no external dc bias magnetic field to enable an obvious αV.
PACS 77.84.-S; 75.80.+q; 77.84.Dy; 77.65.-j; 85.80.Jm 相似文献
164.
J. J. Nuño-Ballesteros B. Oréfice-Okamoto J. N. Tomazella 《Israel Journal of Mathematics》2013,197(1):475-495
Let (X, 0) be a complex analytic isolated determinantal singularity. We will define the vanishing Euler characteristic of (X, 0) and the Milnor number of a holomorphic function germ with an isolated singularity on X, f: (X, 0) → ?. 相似文献
165.
An analytical expression for the von Neumann entropy of the Laughlin wave function is obtained for any possible bipartition between the particles described by this wave function, for a filling fraction nu=1. Also, for a filling fraction nu=1/m, where m is an odd integer, an upper bound on this entropy is exhibited. These results yield a bound on the smallest possible size of the matrices for an exact representation of the Laughlin ansatz in terms of a matrix-product state. An analytical matrix-product state representation of this state is proposed in terms of representations of the Clifford algebra. For nu=1, this representation is shown to be asymptotically optimal in the limit of a large number of particles. 相似文献
166.
Plotnik Y Peleg O Dreisow F Heinrich M Nolte S Szameit A Segev M 《Physical review letters》2011,107(18):183901
We present the experimental observation of bound states in the continuum. Our experiments are carried out in an optical waveguide array structure, where the bound state (guided mode) is decoupled from the continuum by virtue of symmetry only. We demonstrate that breaking the symmetry of the system couples this special bound state to continuum states, leading to radiative losses. These experiments demonstrate ideas initially proposed by von Neumann and Wigner in 1929 and offer new possibilities for integrated optical elements and analogous realizations with cold atoms and optical trapping of particles. 相似文献
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Steiner A Szekely P Szekely O Dvir T Asor R Yuval-Naeh N Keren N Kesselman E Danino D Resh R Ginsburg A Guralnik V Feldblum E Tamburu C Peres M Raviv U 《Langmuir : the ACS journal of surfaces and colloids》2012,28(5):2604-2613
Like-charged solid interfaces repel and separate from one another as much as possible. Charged interfaces composed of self-assembled charged-molecules such as lipids or proteins are ubiquitous. The present study shows that although charged lipid-membranes are sufficiently rigid, in order to swell as much as possible, they deviate markedly from the behavior of typical like-charged solids when diluted below a critical concentration (ca. 15 wt %). Unexpectedly, they swell into lamellar structures with spacing that is up to four times shorter than the layers should assume (if filling the entire available space). This process is reversible with respect to changing the lipid concentration. Additionally, the research shows that, although the repulsion between charged interfaces increases with temperature, like-charged membranes, remarkably, condense with increasing temperature. This effect is also shown to be reversible. Our findings hold for a wide range of conditions including varying membrane charge density, bending rigidity, salt concentration, and conditions of typical living systems. We attribute the limited swelling and condensation of the net repulsive interfaces to their self-assembled character. Unlike solids, membranes can rearrange to gain an effective entropic attraction, which increases with temperature and compensates for the work required for condensing the bilayers. Our findings provide new insight into the thermodynamics and self-organization of like-charged interfaces composed of self-assembled molecules such as charged biomaterials and supramolecular assemblies that are widely found in synthetic and natural constructs. 相似文献
170.
Site-selective spectroscopy is a tool that can be used to uncover the presence of multiple sites available to optically active ions in host lattices. In this Article, we present techniques that can be applied to appraise the different sites that may occur in systems where charge compensation is required or in systems where such compensation is not present. We then consider some garnet crystals doped with chromium ions. For the Cr-doped garnets (YAG, GGG, GSGG, and CYMGG), we present luminescence and lifetime data over a wide temperature range, and infer not only the presence of different centers, but also the interaction among them as a function of temperature. 相似文献