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The homogeneity of the sample load across the radial cross section of analytical scale columns was determined when operating under overload conditions. The study was performed using active flow technology columns operating in parallel segmentation mode. The outlet segmentation ratio was varied to enable different volume fractions of mobile phase, and thus sample, to elute from the peripheral and central flow regions of the column. The amount of solute exiting the peripheral and radial central exit ports was determined as a function of the flow segmentation ratio. The experimental data using an analytical scale column with dimensions, 100?×?4.6?mm, indicated that the sample load distribution was essentially uniform as a function of the column radial cross section. 相似文献
2.
周颖 《数学的实践与认识》2014,(16)
以超负荷运作服务系统为研究对象,考虑顾客止步或中途放弃带来的损失,及顾客等待和被服务所带来的收益,以最大化期望收益为目标,研究如何在顾客到达时做出等待延迟通告决策.构建了基于顾客行为的服务运作系统等待延迟通告决策模型,分析各种情况下的最优解.并通过对各参数的敏感性分析得到一系列有意义的决策和管理建议. 相似文献
3.
This paper proposes a new approach for the time-dependent analysis of stochastic and non-stationary queueing systems. The analysis of a series of stationary queueing models leads to a new approximation of time-dependent performance measures. 相似文献
4.
Multiclass batch arrival retrial queues analyzed as branching processes with immigration 总被引:1,自引:0,他引:1
S. A. Grishechkin 《Queueing Systems》1992,11(4):395-418
TheM/G/1 batch arrival retrial queue is studied by means of branching processes with immigration. We shall investigate this queue when traffic intensity is less than one, tends to one or is greater than one. 相似文献
5.
We consider an open Jackson type queueing network N with input epochs sequence I={T
n
(0),n0}, T
0
(0)=0, assume another input
={
n
(0)} and denote
k
=|
k
(0)–T
k
(0)|, 0=0,
n
=max1kn
k
, n1. Let {T
n
} and {
n
} be the output points in network N and in modified network,
with input
, accordingly. We study the long-run stability of the network output, establishing two-sided bounds for output perturbation via input perturbation. In particular, we obtain conditions that imply max
kn
|T
k
–
k
|=o(n
1/r
) with probability 1 as n for some r>0. This result is also extended to continuous time. We consider successively separate station (service node), tandem and feedforward networks. Then we extend stability analysis to general (feedback) networks and show that in our setting these networks can be reduced to feedforward ones. Similar stability results are also obtained in terms of the number of departures. Application to a tandem network with the overloaded stations is considered. 相似文献
6.
Summary Complex extracts of the plants Azulan and Hemorigen were separated by zonal micropreparative thin-layer chromatography in sandwich chambers of the ES and DS type which permitted zonal application of large volumes of sample, without auxiliary equipment. Application from the edge of the layer, in the frontal chromatography mode, markedly improved the separation efficiency and capacity owing to displacement effects which narrow the initially broad zones. Further improvement of separation efficiency and purity of fractions, revealed by densitometry, was observed using stepwise gradient elution. This was confirmed by extraction of some of the separated fractions from the layer and rechromatography; the composition of these fractions were generally simpler than for the corresponding isocratic chromatograms. 相似文献
7.
赵一强 《应用数学学报(英文版)》2000,16(3):274-282
1. IntroductionThe motivation of writing this paper was from calculating the blocking probability foran overloaded finite system. Our numerical experiments suggested that this probability canbe approximated efficiently by rotating the transition matrix by 180". Some preliminaryresults were obtained and can be found in [11 and [2]. Rotating the transition matrix definesa new Markov chain, which is often called the dual process in the literature, for example,[3--7]. For a finite Markov chain, … 相似文献
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