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首页> 外文期刊>Physical review >One-dimensional nanostructure-guided chain reactions: Harmonic and anharmonic interactions
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One-dimensional nanostructure-guided chain reactions: Harmonic and anharmonic interactions

机译：一维纳米结构指导的链反应：谐波和非谐相互作用

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摘要

We have performed a parametric study of self-propagating chain reactions along a one-dimensional bead-spring array. The coupling between beads is modeled using harmonic and anharmonic Fermi-Pasta-Ulam (FPU)-β and φ~4 potentials. The parameters that define the system are the activation energy (E_a) of the reactive group and the fraction (α) of the reaction enthalpy that is converted to the kinetic energies of the reacted products. The mean conversion for a 100-bead lattice was investigated as a function of these handles. Assemblies of pristine chains with reactive groups having E_a<25 kcal/mol are shown to be inherently unstable. At loads of 3-4 energetic molecules/bead (E_a=35 kcal/mol, α=0.7), the FPU and harmonic lattices behaved similarly with reaction velocities ranging between 8 and 8.5 km/sec. The φ~4 lattice exhibited lower conversions along with the formation of a reaction initiation zone where the velocity was at least half of the bulk value at the aforementioned loads. Fourier analyses of the kinetic energy traces of the φ~4 lattice revealed that only high-frequency excitations led to viable wave propagation, which explains the prominence of the start-up zone at lower loadings of the energetic molecules. High velocity reaction waves are only observed in perfect crystal arrays. The presence of defects in the chain, i.e., beads with weaker force constants, hampers the progress of the wave.
机译：我们已经对一维珠状弹簧阵列自蔓延链反应进行了参数研究。磁珠之间的耦合是使用谐波和非谐费米-帕斯塔-乌拉姆（FPU）-β和φ〜4势来建模的。定义系统的参数是反应性基团的活化能（E_a）和转化为反应产物动能的反应焓的分数（α）。根据这些手柄的功能，研究了100珠晶格的平均转化率。具有具有E_a ＜25kcal / mol的反应性基团的原始链的组装被证明是固有地不稳定的。在3-4个高能分子/珠子的载荷下（E_a = 35 kcal / mol，α= 0.7），FPU和谐波晶格表现出相似的反应速度，反应速度介于8和8.5 km / sec之间。 φ〜4晶格随着反应引发区的形成而表现出较低的转化率，在该反应引发区中，速度至少是上述载荷下体积值的一半。对φ〜4晶格的动能迹线的傅里叶分析表明，只有高频激发才导致可行的波传播，这解释了在高能分子较低负荷下启动区的突出性。仅在完美的晶体阵列中观察到高速反应波。链中缺陷的存在，即力常数较弱的珠子，阻碍了波的前进。

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  • 来源
    《Physical review》 |2009年第17期|174301.1-174301.10|共10页
  • 作者

    Nitish Nair; Michael S. Strano;

  • 作者单位

    Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;

    Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;

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  • 正文语种 eng
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  • 关键词

    anharmonic lattice modes;

    机译：非调和晶格模;

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