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81.
Archiv der Mathematik - In this paper, we establish a sharp integral inequality for n-dimensional closed spacelike submanifolds with constant scalar curvature immersed with parallel normalized mean... 相似文献
82.
Colloid Journal - This article is devoted to the Monte Carlo simulation of the colloidal crystallization kinetics of cadmium selenide (CdSe) nanoparticles (NPs), i.e., the growth of nanoparticles... 相似文献
83.
We study isometric embeddings of a Euclidean space or a Heisenberg group into a higher dimensional Heisenberg group, where both the source and target space are equipped with an arbitrary left-invariant homogeneous distance that is not necessarily sub-Riemannian. We show that if all infinite geodesics in the target are straight lines, then such an embedding must be a homogeneous homomorphism. We discuss a necessary and certain sufficient conditions for the target space to have this ‘geodesic linearity property’, and we provide various examples. 相似文献
84.
Iridium-Catalyzed Enantioselective Hydrogenation of Oxocarbenium Ions: A Case of Ionic Hydrogenation
Tilong Yang Yongjie Sun Heng Wang Prof. Dr. Zhenyang Lin Dr. Jialin Wen Prof. Dr. Xumu Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6164-6170
Ionic hydrogenation has not been extensively explored, but is advantageous for challenging substrates such as unsaturated intermediates. Reported here is an iridium-catalyzed hydrogenation of oxocarbenium ions to afford chiral isochromans with high enantioselectivities. A variety of functionalities are compatible with this catalytic system. In the presence of a catalytic amount of the Brønsted acid HCl, an α-chloroether is generated in situ and subsequentially reduced. Kinetic studies suggest first-order kinetics in the substrate and half-order kinetics in the catalyst. A positive nonlinear effect, together with the half kinetic order, revealed a dimerization of the catalyst. Possible reaction pathways based on the monomeric iridium catalyst were proposed and DFT computational studies revealed an ionic hydrogenation pathway. Chloride abstraction and the cleavage of dihydrogen occur in the same step. 相似文献
85.
86.
Electrophysical, hydro-gas-dynamic, and thermal characteristics of a discharge arising between liquid electrodes are considered. Spatial visualization of flow patterns in the gas discharge region is performed by using the schlieren technique. 相似文献
87.
Nonlinear Dynamics - In this paper, various nonlinear dynamics of a one-degree-of-freedom shallow arch model are investigated. The arch is subject to an imposed displacement of its support that is... 相似文献
88.
JingWei Wen XiaoCong Qiu XiangYu Kong XinYu Chen Fan Yang GuiLu Long 《中国科学:物理学 力学 天文学(英文版)》2020,(3):112-115
Quantum computing is an emerging and promising research field in modern quantum physics and is committed to accelerating traditional calculation processes using the principle of quantum mechanics[1,2].Several computation models have been proposed,including the circuit model[3],topologic quantum computation[4],adiabatic quantum computing[5],and duality quantum computing[6-8].Universal quantum computation generally includes a system initialization,evolutionary control,and a final-state readout[9],where the preparation of the initial state is a key step in the entire process. 相似文献
89.
El-Shehry M. F. El-Hag F. A. A. Ewies E. F. 《Russian Journal of Organic Chemistry》2020,56(1):129-136
Russian Journal of Organic Chemistry - 6-[2-(Furan-2-yl)ethyl]-3-sulfanylidene-3,4-dihydro-1,2,4-triazin-5(2H)-one (1) reacted with chloroacetone to give S-acetonyl derivative which cyclized in... 相似文献
90.