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We derive a master equation for a mirror interacting with the vacuum field via radiation pressure. The dynamical Casimir effect leads to decoherence of a superposition state in a time scale that depends on the degree of "macroscopicity" of the state components, and which may be much shorter than the relaxation time scale. Coherent states are selected by the interaction as pointer states. 相似文献
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Asymmetric hydrosilylation of aryl ketones catalyzed by copper hydride complexed by nonracemic biphenyl bis-phosphine ligands 总被引:1,自引:0,他引:1
Lipshutz BH Noson K Chrisman W Lower A 《Journal of the American Chemical Society》2003,125(29):8779-8789
When complexed by selected ligands in either the BIPHEP or the SEGPHOS series, CuH is an extremely reactive catalyst capable of effecting asymmetric hydrosilylations of aromatic ketones at temperatures between -50 and -78 degrees C. Inexpensive silanes serve as stoichiometric sources of hydride. Substrate-to-ligand ratios exceeding 100000:1 have been documented. The level of induction is usually in the >90% ee category. The nature of the reagent has been investigated using spectroscopic and chemical means, although its composition remains unclear. 相似文献
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Wells JM Chrisman PA McLuckey SA 《Journal of the American Society for Mass Spectrometry》2002,13(6):614-622
Novel instrumentation has been developed which allows for the sequential injection and subsequent reaction of oppositely-charged ions generated via electrospray ionization (ESI) in a quadrupole ion trap mass spectrometer. The instrument uses a DC turning quadrupole to sequentially direct the two ion polarities into the ion trap from ESI sources which are situated 90 degrees from the axial (z) dimension of the trap, and 180 degrees from one another. This arrangement significantly expands the range of ionic reactants amenable to study over previously-used instrumentation. For example, ion/ion reactions of multiply-charged positive ions with multiply-charged negative ions can be studied. Also, reactions of multiply-charged ions with singly-charged ions of opposite polarity that could not be generated by previously used ionization methods, or that could not be efficiently injected through the ion trap ring electrode, can be studied with the new instrument. This capability allows, for example, the charge state manipulation of negatively-charged precursor and product ions derived from proteins and oligonucleotides via proton transfer reactions with singly-charged cations generated by ESI. 相似文献
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<正> 7 解的唯一性 如果不考虑非平衡态和不可逆性,则等能密度理论中的基本命题与经典弹性理论中的在形式上完全相同。无论整个系统的动能是大还是小,图6中(sumform)_o上的面力T_i和在(sumform)_c和在的位移u_i将始终在空间坐标系x_i和时刻i下给出。与一般力学中相同,必须知道有关位移u_i及其时间导数的初始条件。它们的影响则可通过(38)和(39)向等能面转化,从而得到 相似文献
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