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211.
Coleman Marc D. Smith Thomas O. M. Robinson Rod A. Stoffels Benno Wildanger Dominik 《Accreditation and quality assurance》2019,24(2):127-136
Accreditation and Quality Assurance - We report an examination of the capability of the existing measurement infrastructure in the industrial emissions sector for successfully enforcing emission... 相似文献
212.
Smith Thomas O. M. Robinson Rod A. Coleman Marc D. 《Accreditation and quality assurance》2019,24(6):443-449
Accreditation and Quality Assurance - A model has been created to investigate the uncertainty of a gas analyser operating according to the European Standard EN 14181, which ensures that the... 相似文献
213.
M. Abdel-Bary S. Abdel-Samad K-Th. Brinkmann H. Clement J. Dietrich E. Doroshkevich S. Dshemuchadse K. Ehrhardt A. Erhardt W. Eyrich D. Filges A. Filippi H. Freiesleben M. Fritsch W. Gast J. Georgi A. Gillitzer J. Gottwald D. Hesselbarth H. J?ger B. Jakob R. J?kel L. Karsch K. Kilian H. Koch M. Krapp J. Kre? E. Kuhlmann A. Lehmann S. Marcello S. Marwinski S. Mauro W. Meyer P. Michel K. M?ller H. P. Morsch H. M?rtel L. Naumann N. Paul L. Pinna C. Pizzolotto Ch. Plettner S. Reimann M. Richter J. Ritman E. Roderburg A. Schamlott P. Sch?nmeier W. Schroeder M. Schulte-Wissermann T. Sefzick F. Stinzig M. Steinke G. Y. Sun A. Teufel W. Ullrich G. J. Wagner M. Wagner R. Wenzel A. Wilms P. Wintz S. Wirth P. Wüstner P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2010,46(3):435-436
214.
We investigate the extent to which a c.e. degree can be split into two smaller c.e. degrees which are computationally weak. In contrast to a result of Bickford and Mills that can be split into two superlow c.e. degrees, we construct a SJT-hard c.e. degree which is not the join of two superlow c.e. degrees. We also prove that every high c.e. degree is the join of two array computable c.e. degrees, and that not every high2 c.e. degree can be split in this way. Finally we extend a result of Downey, Jockusch and Stob by showing that no totally ω-c.a. wtt-degree can be cupped to the complete wtt-degree. 相似文献
215.
The turbulent energy dissipation rate time-scale and length-scale has been routinely used for the prediction of noise from
turbulent flows, particularly jet streams. However, this is not the only possible choice. In general, scales evolving in a
turbulent medium are threefold. First, those associated with the mean flow; second, those attributed to the turbulence and
the mean flow interactions; and third, scales related to the turbulence-turbulence interactions. In this paper, special attention
will be paid to further study of the underlying physics of aerodynamic noise by examining various time-scales. To do so, three
time scales, namely, dissipation, production, and strain rate time scales, are defined and used in the source modelling to
emphasis the effect of the turbulence structures at different jet regions on the jet noise production mechanism. The required
mean value and turbulence parameters are obtained using a modified k − ∈ turbulence model, and Lighthill’s Acoustic Analogy is used for the prediction of the emanated noise.
The text was submitted by the authors in English. 相似文献
216.
The synthesis of 11H-pyrido[2,1-b]quinazolin-11-one (IV) and derivatives, by the condensation of o-chlorobenzoic acid and 2-aminopyridine in DMF is reported. 相似文献
217.
C. Wade Downey Hadleigh M. Glist Anna Takashima Samuel R. Bottum Grant J. Dixon 《Tetrahedron letters》2018,59(32):3080-3083
Aryl alkyl ketones, acetate esters, and acetamides undergo facile one-pot enol silane formation, Mukaiyama aldol addition, and dehydrosilyloxylation in the presence of an amine base and excess trimethylsilyl trifluoromethanesulfonate. The chalcone and cinnamate products are generally recovered in high yield. The relative stoichiometry of the trimethylsilyl trifluoromethanesulfonate and amine base reagents determines whether the reaction yields the β-silyloxy carbonyl product or the α,β-unsaturated carbonyl. 相似文献
218.
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220.
Rod Cross 《Experimental Mechanics》2014,54(9):1523-1536
Measurements are presented on the oblique impact of a hollow rubber ball incident on a polished granite surface, and the results are compared with those for a solid rubber superball. The hollow ball had a much higher coefficient of sliding friction than the superball, resulting in significant differences in all bounce parameters, at all angles of incidence. The hollow ball gripped the surface at all observed angles of incidence, resulting in one or two reversals in the direction of the friction force during the impact. The friction force was measured directly, as was the rotation speed of the ball during the impact. The results show that the tangential coefficient of restitution of a ball depends on both the coefficient of sliding friction and the ratio of the tangential to the normal vibration frequency of the ball. 相似文献