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液相氧化羰基化合成碳酸二乙酯的新型催化体系CuCl/1,10-菲罗啉/N-甲咪唑 总被引:1,自引:0,他引:1
Diethyl carbonate (DEC) is one of the important green chemicals widely used for organic synthesis because of its various functional groups. DEC is a better octane blending fuel, and has more oxygen in the molecule than methyl tert-butyl ether (MTBE), 40.6% versus 18.2%, which reduces emissions from gasoline and diesel engine. For these reasons many studies on the production of DEC have been extensively carried out. 相似文献
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讨论一类基本的半线性抛物型方程,其在物理上对应具有内部热源的热传导问题,提出了一些爆破的充分条件,讨论了有限爆破点与径向对称情况下的爆破点,并证明爆破速率之上界与下界. 相似文献
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We propose a scheme to generate isolated attosecond pulses
in the water-window spectral region. Based on the numerical solutions of
the single active electron model, we investigate high-order harmonic
generation in helium atoms driven by a multi-cycle two-colour
optical field synthesized by an intense 2000 nm, 20 fs pulse and its
frequency-doubled pulse. When the latter is slightly detuned and
properly phase shifted with respect to the fundamental laser pulse,
an ultra-broad extreme ultraviolet supercontinuum with a spectral
width of 130~eV can be generated in the 270--400~eV spectral regions.
A supercontinuum from 280--340~eV in the water window can be
selected to yield an isolated 67 attosecond pulse without employing
any phase compensation. This water window coherent x-ray pulse with
less than 100 attosecond duration is a potential tool for studying
the ultrafast electronic dynamics of biological samples in water. 相似文献
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