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排序方式: 共有3887条查询结果,搜索用时 15 毫秒
981.
Pedro Maximiano Patrícia V. Mendonça Madson R. E. Santos João R. C. Costa Tamaz Guliashvili Arménio C. Serra Jorge F. J. Coelho 《Journal of polymer science. Part A, Polymer chemistry》2017,55(3):371-381
A new solvent mixture, based on ethanol/reline (EM: eutectic mixture), was investigated for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) near room temperature, for the first time, affording complete catalyst recovery and reuse. The kinetic results revealed that the polymerizations were controlled, with polymers having narrow molecular weight distributions (? < 1.2). The “living” character of the resultant PMA was confirmed by the synthesis of a well‐defined PMA‐b‐PBA block copolymer. Remarkably, it was demonstrated that the Cu(0)/CuBr2/Me6TREN (Me6TREN: tris[2‐(dimethylamino)ethyl]amine) could be recovered from the final reaction mixture and reused for new successful SARA ATRP of MA, suggesting that the reported system could be very attractive from both the economic and environmental perspectives. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 371–381 相似文献
982.
983.
The formulation of a thermodynamic framework for mixtures based on absolute, excess or net adsorption is discussed and the qualitative dependence with pressure and fugacity is used to highlight a practical issue that arises when extending the formulations to mixtures and to the Ideal Adsorbed Solution Theory (IAST). Two important conclusions are derived: the correct fundamental thermodynamic variable is the absolute adsorbed amount; there is only one possible definition of the ideal adsorbed solution and whichever starting point is used the same final IAST equations are obtained, contrary to what has been reported in the literature. 相似文献
984.
Stefano Fanelli 《Journal of Graph Theory》1980,4(4):371-375
Let d1 d2 dp denote the nonincreasing sequence d1, …, d1, d2, …, d2, …, dp, …, dp, where the term di appears ki times (i = 1, 2, …, p). In this work the author proves that the maximal 2-sequences: 7361515, 7561517, 7761519 are planar graphical, in contrast to a conjecture by Schmeichel and Hakimi. 相似文献
985.
Evolution of the deposition rate during pulsed laser deposition of hydroxyapatite coatings and its relation with target morphology 总被引:1,自引:0,他引:1
J.M. Fernández-Pradas L. Clèries P. Serra G. Sardin J.L. Morenza 《Applied Physics A: Materials Science & Processing》2001,72(5):613-618
The evolution of the deposition rate during pulsed laser deposition of hydroxyapatite coatings with a KrF excimer laser was
studied. This evolution was related to the changes produced on the target morphology during laser irradiation. Laser fluences
in the 1.0–5.2 J/cm2 range, typical for the deposition of hydroxyapatite coatings, were investigated. Deposition rates were measured through a
quartz-crystal microbalance, and the target surface was observed by scanning electron microscopy. At the lowest fluences,
the deposition rate decreases as the number of pulses increases. At the same time, a cone structure is developed on the target
surface. At the highest fluences, the deposition rate increases with the number of pulses. In this case, the target surface
becomes rough but cones are not formed. In all cases, an enlargement of the effective irradiated area results. This enlargement
produces the effect of fluence dilution and also an increase of the emitting area. These opposite effects could account for
the different evolutions found for the deposition rate. At low fluences the effect of fluence dilution would predominate over
the increase of the emitting area, and at high fluences the second effect would predominate over the first.
Received: 28 September 2000 / Accepted: 4 October 2000 / Published online: 10 January 2001 相似文献
986.
We prove global comparison results for the p-Laplacian on a p-parabolic manifold. These involve both real-valued and vector-valued maps with finite p-energy. Further L
q
comparison principles in the non-parabolic setting are also discussed. 相似文献
987.
Bruno Franchi Raul Serapioni Francesco Serra Cassano 《Journal of Geometric Analysis》2011,21(4):1044-1084
We study the notion of intrinsic Lipschitz graphs within Heisenberg groups, focusing our attention on their Hausdorff dimension
and on the almost everywhere existence of (geometrically defined) tangent subgroups. In particular, a Rademacher type theorem
enables us to prove that previous definitions of rectifiable sets in Heisenberg groups are natural ones. 相似文献
988.
989.
990.