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The authors prove that in the space of nonsingular transformations of a Lebesgue probability space the type III1 ergodic transformations form a denseG
set with respect to the coarse topology. They also prove that for any locally compact second countable abelian groupH, and any ergodic type III transformationT, it is generic in the space ofH-valued cocycles for the integer action given byT that the skew product ofT with the cocycle is orbit equivalent toT. Similar results are given for ergodic measure-preserving transformations as well.Research supported in part by: Nat. Sci. and Eng. Res. Council #A7163 and # U0080 F.C.A.C. Quebec, NSF Grants # MCS-8102399 and # DMS-8418431. 相似文献
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Beryllium can be precipitated from homogeneous solution as a dense and easily filterable precipitate by the hydrolysis of urea, in the presence of sulphate. The method has been applied to the gravimetric determination of beryllium as oxide. The nature of the precipitate thus obtained has been examined by thermogravimetric, infrared, photomicrographic and X-ray methods. 相似文献
26.
Y. Shi L. Sun J. E. S. Venart R. C. Prasad 《Journal of Thermal Analysis and Calorimetry》2006,86(3):585-590
The transient hot-wire technique is widely used for absolute measurements
of the thermal conductivity and thermal diffusivity of fluids. It is well
established that fluid radiation effects significantly influence these measurements,
especially those for the thermal diffusivity. Corrections for radiation effects
are based on the models developed and deviations of the measured data from
the ideal line source model. In this paper, the effect of fluid radiation
on the measurements of the thermal conductivity of n-pentane
is presented. For comparison, the influence of thermal radiation effect on
measurement of transparent fluids, such as argon is also shown. The difference
between the influence of natural convection and thermal radiation is also
demonstrated. 相似文献
27.
Selenocystine ([Sec]2) and aryl-substituted selenocysteine (Sec) derivatives are synthesized, starting from commercially available amino acid l-serine. These compounds are characterized by a number of analytical techniques such as NMR (1H, 13C and 77Se) and TOF mass spectroscopy. This study reveals that the introduction of amino/imino substituents capable of interacting with selenium may stabilize the Sec derivatives. This study further suggests that the oxidation-elimination reactions in Sec derivatives could be used for the generation of biologically active selenols having internally stabilizing substituents. 相似文献
28.
A. B. Deshpande S. M. Kale S. L. Kapur 《Journal of polymer science. Part A, Polymer chemistry》1973,11(6):1307-1315
Polymerization of methyl methacrylate has been studied with the chromium acetylacetonate–triisobutyl aluminum catalyst system in benzene medium at 40°C. These studies have been carried out at an Al/Cr ratio of 12 to compare the behavior with the previously studied chromium acetyl acetonate–triethyl aluminum catalyst system. The enhanced yield and gelling of polymer suggests a free-radical mechanism of polymerization. Further, the kinetics of polymerization and the heterotactic structure of polymer as determined by NMR examination have led to confirmation of the freeradical mechanism of polymerization of methyl methacrylate by an excess of triisobutylaluminum in the presence of catalyst complex. 相似文献
29.
Katritzky AR Tymoshenko DO Monteux D Vvedensky V Nikonov G Cooper CB Deshpande M 《The Journal of organic chemistry》2000,65(23):8059-8062
The novel three-carbon synthon 1-(1H-1,2, 3-benzotriazol-1-yl)-3-chloroacetone for the synthesis of benzothiazoles, pyrido[1,2-a]indoles, and styryl-substituted indolizines and imidazo[1,2-a]pyridines is reported. The proposed routes are a general and efficient approach for heterocyclizations followed by benzannelations or attachment of arylethenyl pharmacophores. 相似文献
30.
M. Durga Prasad 《Theoretical chemistry accounts》1994,88(5):383-388
Summary Finite order expressions are derived for expectation values and transition matrix elements within the framework of the coupled cluster method. 相似文献