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1.
Artūras Dubickas 《Proceedings Mathematical Sciences》2005,115(4):391-397
Suppose that α > 1 is an algebraic number and ξ > 0 is a real number. We prove that the sequence of fractional partsξα
n
, n = 1, 2, 3, …, has infinitely many limit points except when α is a PV-number and ξ ∈ ℚ(α). For ξ = 1 and α being a rational
non-integer number, this result was proved by Vijayaraghavan. 相似文献
2.
We consider an M/G/1 queue with symmetric service discipline. The class of symmetric service disciplines contains, in particular, the preemptive
last-come-first-served discipline and the processor-sharing discipline. It has been conjectured in Kella et al. [1] that the
marginal distribution of the queue length at any time is identical for all symmetric disciplines if the queue starts empty.
In this paper we show that this conjecture is true if service requirements have an Erlang distribution. We also show by a
counterexample, involving the hyperexponential distribution, that the conjecture is generally not true.
AMS Subject Classifications Primary—60K25; Secondary—90B22 相似文献
3.
4.
Wanpracha Art Chaovalitwongse Oleg A. Prokopyev Panos M. Pardalos 《Annals of Operations Research》2006,148(1):227-250
Epilepsy is among the most common brain disorders. Approximately 25–30% of epilepsy patients remain unresponsive to anti-epileptic
drug treatment, which is the standard therapy for epilepsy. In this study, we apply optimization-based data mining techniques
to classify the brain's normal and epilepsy activity using intracranial electroencephalogram (EEG), which is a tool for evaluating
the physiological state of the brain. A statistical cross validation and support vector machines were implemented to classify
the brain's normal and abnormal activities. The results of this study indicate that it may be possible to design and develop
efficient seizure warning algorithms for diagnostic and therapeutic purposes.
Research was partially supported by the Rutgers Research Council grant-202018, the NSF grants DBI-980821, CCF-0546574, IIS-0611998,
and NIH grant R01-NS-39687-01A1. 相似文献
5.
The use of phase transfer catalysis, PTC, for nucleophillic substitution reactions is well documented.1,2 Included among these reactions is the preparation of both alkyl3 and aryl4 thiocyanates. However, PTC reactions at an acyl carbon are much less common. Brándstróm5 has reported the preparation of acyl azides and Weber6 has used PTC to prepare benzoyl cyanide. Recently Illi7 has used PTC to acylate sterically crowded phenols. 相似文献
6.
7.
Phase transfer catalvsis, PTC, has become a common preparative method in organic chemistry. Numerous aliphatic substitution reactions have been performed yielding cvanides,1 azides,2 thiocyanates,3 ethers,4 and many other types of substitution products.1 相似文献
8.
9.
Carlos A. Martinez Eric Keller Renzo Meijer Gerard Metselaar Gerlof Kruithof Curtis Moore Pei-Pei Kung 《Tetrahedron: Asymmetry》2010,21(19):2408-2412
An efficient four-step biotransformation-mediated synthesis of (1S)-1-(2,6-dichloro-3-fluorophenyl)ethanol in enantiomerically pure form is described. This compound is a key intermediate required for the preparation of PF-2341066, a potent inhibitor of c-Met/ALK that is currently in clinical development. The described synthesis was used to manufacture 6 kg of the title compound and can also be employed to produce the corresponding (1R)-enantiomer. 相似文献
10.
Surface-charge-governed ion transport in nanofluidic channels 总被引:1,自引:0,他引:1
A study of ion transport in aqueous-filled silica channels as thin as 70 nm reveals a remarkable degree of conduction at low salt concentrations that departs strongly from bulk behavior: In the dilute limit, the electrical conductances of channels saturate at a value that is independent of both the salt concentration and the channel height. Our data are well described by an electrokinetic model parametrized only by the surface-charge density. Using chemical surface modifications, we further demonstrate that at low salt concentrations, ion transport in nanochannels is governed by the surface charge. 相似文献