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61.
62.
C. Bartsch J. Gemmer 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,80(4):451-458
We consider models of quasi-1-d, planar atomic wires consisting of several, laterally coupled rows of atoms, with mutually
non-interacting electrons. This electronic wire system is coupled to phonons, corresponding, e.g., to some substrate. We aim
at computing diffusion coefficients in dependence on the wire widths and the lateral coupling. To this end we firstly construct
a numerically manageable linear collision term for the dynamics of the electronic occupation numbers by following a certain
projection operator approach. By means of this collision term we set up a linear Boltzmann equation. A formula for extracting
diffusion coefficients from such Boltzmann equations is given. We find in the regime of a few atomic rows and intermediate
lateral coupling a significant and non-trivial dependence of the diffusion coefficient on both, the width and the lateral
coupling. These results, in principle, suggest the possible applicability of such atomic wires as electronic devices, such
as, e.g., switches. 相似文献
63.
64.
大视角两步彩虹全息术 总被引:4,自引:1,他引:3
本文巧妙地运用了全息图的光路可逆性,采用两面反射镜与小面积全息图相结合,制得了视场角接近180°的大视角彩虹全息图.整个过程分两步完成,无需任何特殊的光学元件.文中给出了实验结果,并进行了讨论. 相似文献
65.
66.
Abulencia A Adelman J Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arguin JF Arisawa T Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Belloni A Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Blair RE Blocker C Blumenfeld B Bocci A 《Physical review letters》2007,98(11):112001
We present the first observation of exclusive e(+)e(-) production in hadron-hadron collisions, using pp[over] collision data at (square root) s = 1.96 TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb(-1). We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E(T) > 5 GeV and pseudorapidity |eta| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9+/-0.3 events. These events are consistent in cross section and properties with the QED process pp[over] --> p + e(+)e(-) + p[over] through two-photon exchange. The measured cross section is 1.6(-0.3)(+0.5)(stat) +/- 0.3(syst) pb. This agrees with the theoretical prediction of 1.71+/-0.01 pb. 相似文献
67.
通过高速撞击实验,探讨了采用小尺寸防护板的可行性。实验中采用的Whipple结构由尺寸变化的1 mm厚防护板(前板)和尺寸固定的3 mm厚舱壁板(后板)组成,防护板与舱壁板间隔10 cm。防护板为边长分别为8、12、16和20 cm的方形2A12铝合金板,舱壁板为边长为20 cm的方形5A06铝合金板。实验过程中均采用直径为4 mm的铝合金球形弹丸,撞击速度为1.45~1.71 km/s。实验结果表明:Whipple防护结构在舱壁板被击穿的概率大于0.8的条件下和击穿概率为0的条件下的极限速度以及舱壁板临界击穿条件下的速度都与防护板尺寸无关;并且,防护板前后表面击穿孔的直径及击穿孔侧壁的倾斜角也与防护板尺寸无关;但是,在速度相同的条件下随着板尺寸的增大,防护板板面的最大挠度增大,而且,防护板挠曲面的凸凹方向也由单一的凹向变成凸凹方向交替出现;随着速度的增加和板尺寸的增大,防护板最大挠度的增量减小。 相似文献
68.
Thomas Bartsch Tomáš Dohnal Michael Plum Wolfgang Reichel 《NoDEA : Nonlinear Differential Equations and Applications》2016,23(5):52
We consider the nonlinear curl-curl problem \({\nabla\times\nabla\times U + V(x) U= \Gamma(x)|U|^{p-1}U}\) in \({\mathbb{R}^3}\) related to the Kerr nonlinear Maxwell equations for fully localized monochromatic fields. We search for solutions as minimizers (ground states) of the corresponding energy functional defined on subspaces (defocusing case) or natural constraints (focusing case) of \({H({\rm curl};\mathbb{R}^3)}\). Under a cylindrical symmetry assumption corresponding to a photonic fiber geometry on the functions V and \({\Gamma}\) the variational problem can be posed in a symmetric subspace of \({H({\rm curl};\mathbb{R}^3)}\). For a defocusing case \({{\rm sup} \Gamma < 0}\) with large negative values of \({\Gamma}\) at infinity we obtain ground states by the direct minimization method. For the focusing case \({{\rm inf} \Gamma > 0}\) the concentration compactness principle produces ground states under the assumption that zero lies outside the spectrum of the linear operator \({\nabla \times \nabla \times +V(x)}\). Examples of cylindrically symmetric functions V are provided for which this holds. 相似文献
69.
D. I. Glazier M. Seimetz J. R. M. Annand H. Arenhövel M. Ases Antelo C. Ayerbe P. Bartsch D. Baumann J. Bermuth R. Böhm D. Bosnar M. Ding M. O. Distler D. Elsner J. Friedrich S. Hedicke P. Jennewein G. Jover Ma nas F. H. Klein F. Klein M. Kohl K. W. Krygier K. Livingston I. J. D. MacGregor M. Makek H. Merkel P. Merle D. Middleton U. Müller R. Neuhausen L. Nungesser M. Ostrick R. Pérez Benito J. Pochodzalla Th. Pospischil M. Potokar A. Reiter G. Rosner J. Sanner H. Schmieden A. Süle Th. Walcher D. P. Watts M. Weis 《The European Physical Journal A - Hadrons and Nuclei》2005,24(1):101-109
The electric form factor of the neutron, GE,n, has been measured at the Mainz Microtron by recoil polarimetry in the quasielastic D(¯e, e¯n)p reaction. Three data points have been extracted at squared four-momentum transfers Q
2 = 0.3, 0.6 and 0.8 (GeV/c)2. Corrections for nuclear binding effects have been applied.This revised version was published online in March 2005. In the previous version, the email address of one author was inadvertently assigned to multiple authors. 相似文献
70.
It is shown by experimental examples how the postexposure relaxation of a photochemically induced grating used to study the diffusion of a molecular probe by the holographic relaxation method depends on the molecular mechanism of the grating formation, medium inhomogeneity, and relative shift of grating parts, as well as the grating strength. The adequate consideration of the factors influencing the observed behavior of the grating provides for the possibility not only to correctly retrieve information about the diffusion, but also to extend the range of studied phenomena. 相似文献