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Physics in Perspective - The American physicist John Wheeler once told his colleague Richard Feynman that, in case of war, “it’s better to forget physics and tell the admirals and... 相似文献
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Borghesi M Bulanov S Campbell DH Clarke RJ Esirkepov TZh Galimberti M Gizzi LA MacKinnon AJ Naumova NM Pegoraro F Ruhl H Schiavi A Willi O 《Physical review letters》2002,88(13):135002
A novel physical phenomenon has been observed following the interaction of an intense (10(19) W/cm(2)) laser pulse with an underdense plasma. Long-lived, macroscopic bubblelike structures have been detected through the deflection that the associated electric charge separation causes in a proton probe beam. These structures are interpreted as the remnants of a cloud of relativistic solitons generated in the plasma by the ultraintense laser pulse. This interpretation is supported by an analytical study of the soliton cloud evolution, by particle-in-cell simulations, and by a reconstruction of the proton-beam deflection. 相似文献
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The pentaamminecobalt(III) complex with the 3-cyano-2,4-pentanedionate anion coordinated through the nitrile nitrogen has been characterized by X-ray crystallography. The crystals of [(NH3)5CoNCacac](Cl)(ClO4)·2H2O are triclinic, space group P
, a = 10.245(2) Å, b = 14.071(4) Å, c = 6.971(2) Å, = 90.03(3)°, β = 109.86(2)°, γ = 108.91(2)°, V= 887.1 Å3, Z = 2, Dc = 1.64 g cm−3, F(000) = 456, Mo-K radiation, λ = 0.71069 Å, μ(Mo-K) = 12.7 cm−1. The structure was determined by the heavy-atom method, and refined by block-diagonal least-squares calculations, R = 0.0537, Rw = 0.0607, for 2499 observed reflections. Principal dimensions are: Co---N(NH3) trans to NCacac− 1.940(5), other Co---N(NH3) 1.967(2), Co---N(NCacac−) 1.911(5) Å. The pendant acac moiety is best described in terms of a delocalized bond network with, for example, C---C distances in the range 1.44–1.52(1) Å. Several reactions involving this free acac group are also described including the preparation and characterization of the dimeric species pentaamminecobalt(III) - μ - (3 - cyano - 2,4 - pentanedionato) - bis(propylenediamine) cobalt(III) perchlorate. 相似文献
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