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In many generic combustion models, one finds that a combustionwave will develop with a specific wave speed. However, thereare possible initial temperature profiles which do not evolveinto such waves, but rather die out to the ambient temperature.There can exist, in some models, a clear distinction betweenthose initial conditions that do evolve into combustion wavesand those that do not; this is sometimes referred to as thewatershed initial condition. When fuel consumption is consideredto be negligible, analytical methods can be used to obtain theexact watershed. In this paper, we consider the problem of determiningpseudo-watersheds and ascertaining the relationship betweenthese pseudo-watersheds and the exact watersheds. In the processa novel weight-function approach for infinite spatial domainsis developed. 相似文献
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利用激光蒸发团簇源产生Wn团簇束,团簇束通过一个充有N2气体分 子的低压反应池,利用飞行时间质谱探测反应产物,在类单次碰撞条件下研究了W+10 -W+50和N2分子的反应性,在室温条件下测量了N2分子与W+n团簇反应的 反应几率。团簇尺寸在10~26原子的团簇与N2分子的反应几率与团簇尺寸有很强的相关性 ,对n=16,22,23的团簇具有比较高的反应性。W+n与N2分子的反应性与Wn与N 2分子的反应性显示出相似的规律性。 相似文献
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针对现有Web使用记录挖掘方法发现的知识和规则存在不精确或不完全的问题,提出了一种改进的基于粗糙近似的Web事务聚类算法.该算法首先对原有算法得到的每个类,用关系矩阵找出在这个类中不满足传递性的对象,然后在该对象的集合(类)上用关系矩阵找出在这个类中不满足传递性的对象,再对每个类进行分割,使其满足关系R的传递性,克服了现有算法不满足关系的传递性和在某些情况下得到的结果不准确的缺点. 相似文献
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An energy-dispersive electron probe X-ray microanalysis (ED-EPMA) technique using an energy-dispersive X-ray detector with
an ultra-thin window, designated as low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N and O, as well as higher-Z elements that can be analysed by conventional ED-EPMA. The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual particles has
improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally
important atmospheric particles, e.g. sulphates, nitrates, ammonium and carbonaceous particles, contain low-Z elements. To demonstrate its practical applicability, the application of the low-Z particle EPMA for the characterization of Asian Dust, urban and subway aerosol particles is shown herein. In addition, it
is demonstrated that the Monte Carlo calculation can also be applied in a quantitative single-particle analysis using transmission
electron microscopy (TEM) coupled with energy-dispersive X-ray spectrometry (EDX), showing that the technique is useful and
reliable for the characterization of submicron aerosol particles. 相似文献
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Two novel metabolites, containing four bromotyrosine units, have been isolated from the sponge . 相似文献
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利用激光蒸发团簇源产生Wn 团簇束 ,团簇束通过一个充有N2 气体分子的低压反应池 ,利用飞行时间质谱探测反应产物 ,在类单次碰撞条件下研究了W 10 -W 50 和N2 分子的反应性 ,在室温条件下测量了N2 分子与W n 团簇反应的反应几率。团簇尺寸在 10~ 2 6原子的团簇与N2 分子的反应几率与团簇尺寸有很强的相关性 ,对n =16,2 2 ,2 3的团簇具有比较高的反应性。W n 与N2 分子的反应性与Wn 与N2 分子的反应性显示出相似的规律性。 相似文献
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An improved two-dimensional gel electrophoresis procedure has been developed utilizing isolated nuclear matrix proteins. The proteins of the cellular nuclear matrix are tissue specific. They are an example of a protein set whose two-dimensional electrophoretic patterns afford much information of clinical significance. However, current two-dimensional gel techniques were not completely satisfactory for the small amounts of protein present in tissue samples. There was a need for a two-dimensional gel procedure which was capable of increased sensitivity and resolution and at the same time was reliable and reproducible. This has been accomplished by implementing several modifications to the current two-dimensional gel procedures. In addition, changes were introduced in the silver staining process of the gels to increase the signal to background ratio. The overall procedure affects a dramatic increase in the resolution and clarity of the proteins visualized on two-dimensional gels and is no more laborious than current techniques. 相似文献
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