6,311 research outputs found

    Bending and springback prediction method based on multi-scale finite element analyses for high bendability and low springback sheet generation

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    In this study, a sheet bendability and springback property evaluation technology through bending test simulations is newly developed using our multi-scale finite element analysis code, which is based on the crystallographic homogenization method

    Topological Floquet-Thouless energy pump

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    We explore adiabatic pumping in the presence of periodic drive, finding a new phase in which the topologically quantized pumped quantity is energy rather than charge. The topological invariant is given by the winding number of the micromotion with respect to time within each cycle, momentum, and adiabatic tuning parameter. We show numerically that this pump is highly robust against both disorder and interactions, breaking down at large values of either in a manner identical to the Thouless charge pump. Finally, we suggest experimental protocols for measuring this phenomenon.Comment: 4 pages, 4 figures. Minor replacements and references adde

    Regularizing effect and local existence for non-cutoff Boltzmann equation

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    The Boltzmann equation without Grad's angular cutoff assumption is believed to have regularizing effect on the solution because of the non-integrable angular singularity of the cross-section. However, even though so far this has been justified satisfactorily for the spatially homogeneous Boltzmann equation, it is still basically unsolved for the spatially inhomogeneous Boltzmann equation. In this paper, by sharpening the coercivity and upper bound estimates for the collision operator, establishing the hypo-ellipticity of the Boltzmann operator based on a generalized version of the uncertainty principle, and analyzing the commutators between the collision operator and some weighted pseudo differential operators, we prove the regularizing effect in all (time, space and velocity) variables on solutions when some mild regularity is imposed on these solutions. For completeness, we also show that when the initial data has this mild regularity and Maxwellian type decay in velocity variable, there exists a unique local solution with the same regularity, so that this solution enjoys the CC^\infty regularity for positive time

    Well-posedness of the Viscous Boussinesq System in Besov Spaces of Negative Order Near Index s=1s=-1

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    This paper is concerned with well-posedness of the Boussinesq system. We prove that the nn (n2n\ge2) dimensional Boussinesq system is well-psoed for small initial data (u0,θ0)(\vec{u}_0,\theta_0) (u0=0\nabla\cdot\vec{u}_0=0) either in (B,11B,1,1)×Bp,r1({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times{B}^{-1}_{p,r} or in B,1,1×Bp,1,ϵ{B^{-1,1}_{\infty,\infty}}\times{B}^{-1,\epsilon}_{p,\infty} if r[1,]r\in[1,\infty], ϵ>0\epsilon>0 and p(n2,)p\in(\frac{n}{2},\infty), where Bp,qs,ϵB^{s,\epsilon}_{p,q} (sRs\in\mathbb{R}, 1p,q1\leq p,q\leq\infty, ϵ>0\epsilon>0) is the logarithmically modified Besov space to the standard Besov space Bp,qsB^{s}_{p,q}. We also prove that this system is well-posed for small initial data in (B,11B,1,1)×(Bn2,11Bn2,1,1)({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times({B}^{-1}_{\frac{n}{2},1}\cap{B^{-1,1}_{\frac{n}{2},\infty}}).Comment: 18 page

    Ecstasy: 3,4-Methylenedioxymethamphetamine (MDMA)

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    This is the published version. Copyright 1998 International Union of CrystallographyThe crystal structure of 3,4-methylenedioxymethamphetamine {systematic name: N-methyl-l-[3,4-(methylenedioxy) phenyl]-2-aminopropane } hydrochloride, C 11H 15 - NO2.HC1, also known as 'ecstasy' or MDMA, has been determined by X-ray diffraction

    Analysis of the Demagnetization Process of Nd-Fe-B Sintered Magnets at Elevated Temperatures by Magnetic Domain Observation Using a Kerr Microscope

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    Magnetization reversal and its propagation in sintered Nd–Fe–B magnets were clearly observed at elevated temperatures up to 150 °C using a Kerr microscope, image processing, and photo editing. Simultaneous magnetization reversal in several grains along the easy axis direction occurred at elevated temperature, and the extent of simultaneous magnetization reversal increased with temperature. This indicates that reduction in the coercivity of Nd–Fe–B sintered magnets at elevated temperatures is attributable to decrease in anisotropy and insufficient pinning of domain walls at grain boundaries

    Optical Hall Effect in the Integer Quantum Hall Regime

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    Optical Hall conductivity σxy(ω)\sigma_{xy}(\omega) is measured from the Faraday rotation for a GaAs/AlGaAs heterojunction quantum Hall system in the terahertz frequency regime. The Faraday rotation angle (\sim fine structure constant \sim mrad) is found to significantly deviate from the Drude-like behavior to exhibit a plateau-like structure around the Landau-level filling ν=2\nu=2. The result, which fits with the behavior expected from the carrier localization effect in the ac regime, indicates that the plateau structure, although not quantized, still exists in the terahertz regime.Comment: 4 pages, 4 figure
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