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The main purpose of this paper is to establish the mapping relation between metric spaces and sn-metric spaces. 相似文献
13.
Bin Li Shun Liu Minhua Wu Qiao Lin Wanhong Deng Shaohua Jiang Lu Chen 《Tetrahedron letters》2018,59(38):3467-3472
A highly selective double reductive aminations of aldehydes with anilines to give tertiary amines, in the presence of [RuCl2(p-cymene)]2 catalyst and PhSiH3, was performed under neat conditions. Piperidine derivatives were successfully synthesized by a double reductive amination followed by cyclisation from glutaric dialdehyde with anilines. 相似文献
14.
In this paper we estimate the size of the ρn’s in the famous L. Zalcman’s Lemma. With it, we obtain a uniqueness theorem for entire functions and their first derivatives,
which improves and generalizes the related results of Rubel and Yang and of Li and Yi. Some examples are provided to show
the sharpness of our result. As an application, we prove that R. Brück’s conjecture is true for a class of functions.
Received: 30 October 2008, Revised: 5 February 2009 相似文献
15.
Nanocrystal samples (particle size about 90 nm) of Eu3+-doped rutile titanium dioxide (TiO2) nanocrystals (rutile Eu3+/TiO2 nanocrystals) were synthesized by the sol–gel method with hydrothermal treatment. The pressure effect on photoluminescence (PL) and Raman spectra of the rutile Eu3+/TiO2 nanocrystals was investigated with a diamond anvil cell under hydrostatic pressure condition. Raman spectra of the samples at high pressures indicated that the critical pressure for the transition from the rutile phase to a new baddeleyite-type phase was between 10 and 14.2 GPa. The position of Raman bands shifted to high wavenumbers and the PL intensity of 5D 0→7F 2 transition of Eu3+ decreased down to zero with the increase of pressure before the phase transition occurred. After releasing the pressure, the rutile phase was not recovered and a α-PbO2-type phase was observed at ambient pressure. 相似文献
16.
Let S be an ordered semigroup.In this paper,we characterize ordered semigroups in which the radical of every ideal(right ideal,bi-ideal) is an ordered subsemigroup(resp.,ideal,right ideal,left ideal,bi-ideal,interior ideal) by using some binary relations on S. 相似文献
17.
曹文胜 《数学物理学报(A辑)》2010,30(2):531-541
两四元数相似当且仅当它们有相同的实部和模,两四元数合相似当且仅当它们有相同的模.应用四维Clifford代数的矩阵表示,得到了四维Clifford代数中两元素相似或合相似的充分必要条件. 相似文献
18.
We numerically investigate the complete chaotic synchronization mechanism of polarization mode of VCSEL with anisotropic optical feedback. Firstly, the synchronization quality of the x-linear polarization (LP) mode and the y-LP mode are both periodically changed with the angle θ between the polarizer and the light axes. Secondly, in a enough large scale region of the feedback coefficient and the injection current, where each LP mode can obtained good synchronization quality when the angle θ exists in the former half period region and the injection current is fixed at a certain value, which is over the threshold current. Under this condition, their synchronization quality is independent of the polarization states. By contrast, in the latter half period region of the angle θ where each LP mode can be obtained very instable and inferior synchronized quality. At last, the robustness of the synchronization scheme is sensitive to the internal and external parameter mismatch between the transmitter-VCSEL and the receiver-VCSEL. 相似文献
19.
In this paper, two necessary and sufficient conditions, and a sufficient condition of A()-acceptability for (n, m) rationa approximation to function exp(z) are given, where a (0, x/2). A necesary and sufficient condition of A-acceptability for (n, m) rational approximation to exp(z) of order p is obtained, where nmp. 相似文献
20.
Xiang-Yun Xie 《Semigroup Forum》2001,63(2):180-190
In this paper, some characterizations that an ordered semigroup S is a band of weakly r-archimedean ordered subsemigroups of S are given by some relations on S . We prove that an ordered semigroup S is a band of weakly r -archimedean ordered subsemigroups if and only if S is regular band of weakly r -archimedean ordered subsemigroups. Finally, we obtain that a negative ordered semigroup S is a band of weakly r-archimedean ordered subsemigroups of S if and only if S is a band of r-archimedean ordered subsemigroups of S . As an application the corresponding results on semigroups without order can be obtained by moderate modifications.
August 27, 1999 相似文献