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91.
Molecular Diversity - In this study, an efficient and convenient domino Michael addition/intramolecular cyclization protocol is presented for the synthesis of biologically relevant... 相似文献
92.
Jhansi Rani Sunkara Sathish Mohan Botsa 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2020,94(2):392-400
Russian Journal of Physical Chemistry A - Recently the researchers have shown great interest on photocatalysis, especially in dyes degradation by nanocomposites under visible light. In this work,... 相似文献
93.
Nieto Alexandre R. Zotos Euaggelos E. Seoane Jesús M. Sanjuán Miguel A. F. 《Nonlinear dynamics》2020,99(4):3029-3039
Nonlinear Dynamics - We show that the presence of KAM islands in nonhyperbolic chaotic scattering has deep implications on the unpredictability of open Hamiltonian systems. When the energy of the... 相似文献
94.
95.
Neha Rani Kumar Abhijeet R. Agrawal Dr. Sanjio S. Zade 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14064-14071
Azulene is a non-alternant non-benzenoid aromatic system, and in turn, it possesses unusual photophysical properties. Azulene-based conjugated systems have received increasing interest in recent years as optoelectronic materials. Despite the routes available for the preparation of substituted azulene derivatives, there remain few methods that allow regioselective substitution on the seven-membered ring of azulenes due to the subtle reactivity difference among the various positions. This report explores the reactivity of substituted tropolones as the azulene precursors and also provides a new method to create 5-substituted azulenes. The reaction of cyanoacetate enolate with unsubstituted 2-methoxytropone affords azulene through the attack of the nucleophile on the C-2 center (normal pathway). We have observed that 3-substituted 2-methoxytropones undergo steric-guided nucleophilic addition at the C-7 center (abnormal pathway) to afford 5-substituted azulene derivatives. Based on this observation and DFT calculation, a new synthetic strategy is devised for the regioselective synthesis of 5-substituted multifunctional azulenes, which cannot be accessed by any other method. 相似文献
96.
Sangepu Bhavanarushi Zhi-Bin Luo Gandu Bharath JettiVatsala Rani Imran Khan Yin Xu Bin Liu Jimin Xie 《Journal of heterocyclic chemistry》2020,57(2):751-760
This paper investigates the seismic and collapse performance of shape memory alloy (SMA) braced steel frame structures considering the effects of various brace design parameters and ultimate state of SMAs. An SMA braced steel frame building is designed to have comparable strength and stiffness with a steel-moment resisting frame selected as case study building. Then, the stiffness and ultimate deformation capacity of the SMA braces in the initially designed reference SMA braced frame are systematically varied. First, the static pushover analysis and incremental dynamic analysis (IDA) are employed to illustrate the significance of SMA brace failure consideration in seismic performance assessment of steel frames with SMA elements. Then, the influence of SMA brace initial stiffness and ultimate deformation capacity on the seismic and collapse performance of SMA braced frames are studied through pushover analyses, nonlinear response history analyses, and IDA. The results show that the SMA brace initial stiffness does not affect the interstory drift and floor absolute acceleration response at design and maximum considered earthquake (MCE) level seismic hazard or collapse capacity of the frame. However, it has considerable influence on post-event functionality of the frame. It is also found that the SMA brace ultimate deformation capacity should be at least 80% of maximum inter-story drift demand at MCE level for satisfactory seismic performance, while larger values provide higher collapse capacity for the SMA braced frame. 相似文献
97.
Kathing C. Singh N. G. World Star Rani J. Nongrum R. Nongkhlaw R. 《Russian Journal of Organic Chemistry》2020,56(9):1628-1634
Russian Journal of Organic Chemistry - An efficient synthetic method for the highly selective synthesis of pharmacologically active 1,2-disubstituted benzimidazole derivatives... 相似文献
98.
We prove that there exists a finite universal Korovkin set with respect to positive spectral contraction operators for a Segal
algebra on a locally compact abelian groupG if and only ifĜ is finite dimensional separable metrizable space. 相似文献
99.
Let T : J → J be an expanding rational map of the Riemann sphere acting on its Julia set J andf : J →R denote a Hölder continuous function satisfyingf(x)?log | T′(x vb for allx in J. Then for any pointz 0 in J define the set Dz 0(f) of “well-approximable” points to be the set of points in J which lie in the Euclidean ball $B(\gamma ,{\text{ exp(}} - \sum {_{i - 0}^{\mathfrak{n} - 1} } f(T^\ell x)))$ for infinitely many pairs (y, n) satisfying T n (y)=z0. We prove that the Hausdorff dimension of Dz 0(f) is the unique positive numbers(f) satisfying the equation P(T,?s(f).f)=0, where P is the pressure on the Julia set. This result is then shown to have consequences for the limsups of ergodic averages of Hölder continuous functions. We also obtain local counting results which are analogous to the orbital counting results in the theory of Kleinian groups. 相似文献
100.
dc conductivity as a function of temperature has been measured for as-evaporated and annealed films of amorphous Si, grown by the vacuum evaporation technique. The experimental data suggest that conduction in the higher temperature range (~175–300 K) is by the thermally activated holes in the localized states near the valence band edge while conduction in the lower temperature range (~77–175 K) is found to be thermally assisted tunnelling in the localized states near the Fermi level. The activation energy for both the processes is found to increase with an increase in the annealing temperature. The average hopping distance, calculated for conduction near the Fermi level, is also found to increase with an increase in the annealing temperature. 相似文献