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In this paper we identify certain classes of non-stretch mappings that enjoy a sharp estimate of the Beurling–Ahlfors operator. We first make use of a property of subharmonic functions to prove that the Bañuelos–Wang conjecture and the Iwaniec conjecture are true for a class of mappings that satisfy a quasilinear conjugate Beltrami equation. By utilizing the principal solutions of Beltrami equations, we further explicitly construct some classes of non-stretch mappings for which the Bañuelos–Wang conjecture and the Iwaniec conjecture are true. 相似文献
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We give an explicit formula of the quasihyperbolic distance from a point to a line in the once punctured plane and prove the geodesic is orthogonal to the line. By this result, we give an affirmative answer to the open problem in the case of twice and thrice punctured planes raised by Klén and generalize their estimates. We also construct an example to show that the cosine inequality does not hold in twice or thrice punctured planes. 相似文献
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The main result of this paper is the sharp generalized Schwarz-Pick inequality for euclidean harmonic quasiconformal mappings with convex ranges, which generalizes a result given by Mateljevi?. As its applications, we obtain the property of quasi-isometry with respect to the Poincaré distance and an analogue of the Koebe theorem for this class of mappings. 相似文献
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Motivated by the result of Chen-Liu-Ru [1],we investigate the value distribution properties for the generalized Gauss maps of weakly complete harmonic surfaces immersed in Rn with ramification,which can be seen as a generalization of the results in the case of the minimal surfaces.In addition,we give an estimate of the Gauss curvature for the K-quasiconfomal harmonic surfaces whose generalized Gauss map is ramified over a set of hyperplanes. 相似文献
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Dr. Junjiang Jin Xingdi Zhang Prof. Yongsheng Li Dr. Hua Li Wei Wu Yunlong Cui Qian Chen Dr. Liang Li Dr. Jinlou Gu Dr. Wenru Zhao Prof. Jianlin Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(51):16549-16555
Uniform mesoporous zeolite ZSM‐5 crystals have been successfully fabricated through a simple hydrothermal synthetic method by utilizing ammonium‐modified chitosan and tetrapropylammonium hydroxide (TPAOH) as the meso‐ and microscale template, respectively. It was revealed that mesopores with diameters of 5–20 nm coexisted with microporous network within mesoporous ZSM‐5 crystals. Ammonium‐modified chitosan was demonstrated to serve as a mesoporogen, self‐assembling with the zeolite precursor through strong static interactions. As expected, the prepared mesoporous ZSM‐5 exhibited greatly enhanced catalytic activities compared with conventional ZSM‐5 and Al‐MCM‐41 in reactions involving bulky molecules, such as the Claisen–Schmidt condensation of 2‐hydroxyacetophenone with benzaldehyde and the esterification reaction of dodecanoic acid and 2‐ethylhexanol. 相似文献
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聚二甲基甲基氢化硅氧烷(简称含氢硅油)是一类反应性有机硅聚合物。这类聚合物中含有的si—H键十分活泼,其化学性质在有机硅工业中十分有用,如合成不同类型的硅油、有机硅树脂、硅橡胶、改性有机硅表面活性剂等。 相似文献
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Fu Yuwei Luo Santu Li Xingdi Chen Chi Wang Chuang Zhang Zaiqin Liu Dingxin 《Plasma Chemistry and Plasma Processing》2022,42(6):1265-1278
Plasma Chemistry and Plasma Processing - C5F10O-insulated environmental-friendly power equipment has great potential to be used in the near future to reduce greenhouse effect. During maintenance,... 相似文献
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含柔性间隔基的扩链脲增韧环氧树脂性能研究——环氧树脂/扩链脲/双氰双胺体系性能研究 总被引:1,自引:0,他引:1
合成了含不同分子量柔性间隔基的扩链脲(Ui),并对其与双氰双胺共同固化环氧树脂体系的反应活性、抗冲击性能、动态力学性能、形态结构及贮存性能进行了考察。结果表明:含分子量为400的聚乙二醇柔性链的扩链脲/双氰双胺/环氧树脂固化体系的抗冲击强度较单纯双氰双胺/环氧树脂固化体系提高了7倍左右,其冲击试样断面电镜照片呈韧性断裂的特征。扩链脲的反应活性基本不受分子中聚乙二醇链段分子量的影响。环氧树脂/扩链脲/双氰双胺体系在50℃下贮存期可达1~2天。 相似文献
10.
In this paper we obtain a necessary and sufficient condition for the harmonicity of the inverse of a harmonic diffeomorphism. As an application, we give explicit representations of reversible logharmonic diffeomorphisms. As another application, we connect the harmonicity of the inverse of a hyperbolic harmonic quasiconformal diffeomorphism with the Schoen conjecture. 相似文献