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61.
62.
Experimental results on convective heat transfer from a single cube on a flat surface are presented for different attack angles
to the incident flow and Reynolds numbers. The character of vortex formation and the effect of flow structure on heat transfer
at detached flow around a cube were studied by visualization. Local heat transfer and heat transfer averaged over the separate
faces and the whole lateral surface of the cube were studied. Contribution of separate cube faces to total heat transfer depending
on the attack angle was estimated. Data obtained were compared with those published in literature. The reasons for observed
differences caused by the effect of many factors: boundary layer thickness, turbulence level of the incident flow, channel
constraint, etc., are analysed. 相似文献
63.
M. E. Gushchin S. V. Korobkov A. V. Kostrov D. A. Odzerikho S. E. Priver A. V. Strikovskii 《JETP Letters》2010,92(2):85-90
It has been shown experimentally that the diamagnetic effect appearing when electrons of a magnetized plasma in the antenna
near field are accelerated under electron cyclotron resonance conditions can be used to generate low-frequency waves. The
amplitude modulation of a signal supplied to the antenna is accompanied by the modulation of the diamagnetic effect and leads
to the emission of waves at the modulation frequency to the surrounding plasma. In this process, the extended plasma region
containing accelerated electrons serves as a parametric bodiless antenna. The results of the model laboratory experiments
make it possible to propose a method for the parametric generation of low-frequency whistler waves in the Earth’s ionosphere
by a powerful amplitude-modulated signal supplied to the satellite-borne antenna. 相似文献
64.
65.
In type III seesaw utilized to explain the observed solar and atmospheric neutrino oscillations the Standard Model (SM) particle spectrum is extended by introducing three SU(2)L triplet fermion fields. This can have important implications for the SM Higgs boson mass (MH) bounds based on vacuum stability and perturbativity arguments. We compute the appropriate renormalization group equations for type III seesaw, and then proceed to identify regions of the parameter space such that the SM Higgs boson mass window is enlarged to 125 GeV?MH?174 GeV, with the type III seesaw scale close to TeV. We also display regions of the parameter space for which the vacuum stability and perturbativity bounds merge together for large neutrino Yukawa couplings. Comparison with type I seesaw is also presented. 相似文献
66.
We consider random conformally invariant paths in the complex plane (SLEs). Using the Coulomb gas method in conformal field theory, we rederive the mixed multifractal exponents associated with both the harmonic measure and winding (rotation or monodromy) near such critical curves, previously obtained by quantum gravity methods. The results also extend to the general cases of harmonic measure moments and winding of multiple paths in a star configuration. 相似文献
67.
Gang Yan Bereket L. Zekarias Dr. Xiaoyu Li Victor A. Jaffett Ilia A. Guzei Prof. Dr. Jennifer E. Golden 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(11):2486-2492
A highly efficient 2-chloroquinazolin-4(3H)-one rearrangement was developed that predictably generates either twisted-cyclic or ring-fused guanidines in a single operation, depending on the presence of a primary versus secondary amine in the accompanying diamine reagent. Exclusive formation of twisted-cyclic guanidines results from pairing 2-chloroquinazolinones with secondary diamines. Use of primary amine-containing diamines permits a domino quinazolinone rearrangement/intramolecular cyclization, gated through (E)-twisted-cyclic guanidines, to afford ring-fused N-acylguanidines. This scalable, structurally tolerant transformation generated 55 guanidines and delivered twisted-cyclic guanidines with robust plasma stability and an abbreviated total synthesis of an antitumor ring-fused guanidine (4 steps, 55 % yield). 相似文献
68.
Hanfi Mohamed Y. Yarmoshenko Ilia V. Seleznev Andrian A. Zhukovsky Michael V. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(3):831-839
Journal of Radioanalytical and Nuclear Chemistry - A castable polyurethane (PUR) with soft segment made by polytetrahydrofuran polyol (or polytretramethylene ether glycol?=?PTMEG)... 相似文献
69.
Chase A. Salazar Joseph J. Gair Kaylin N. Flesch Ilia A. Guzei Jared C. Lewis Shannon S. Stahl 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):10965-10969
Mono-N-protected amino acids (MPAAs) are increasingly common ligands in Pd-catalyzed C−H functionalization reactions. Previous studies have shown how these ligands accelerate catalytic turnover by facilitating the C−H activation step. Here, it is shown that MPAA ligands exhibit a second property commonly associated with ligand-accelerated catalysis: the ability to support catalytic turnover at substoichiometric ligand-to-metal ratios. This catalytic role of the MPAA ligand is characterized in stoichiometric C−H activation and catalytic C−H functionalization reactions. Palladacycle formation with substrates bearing carboxylate and pyridine directing groups exhibit a 50–100-fold increase in rate when only 0.05 equivalents of MPAA are present relative to PdII. These and other mechanistic data indicate that facile exchange between MPAAs and anionic ligands coordinated to PdII enables a single MPAA to support C−H activation at multiple PdII centers. 相似文献
70.
Korobkov S. V. Gushchin M. E. Strikovskiy A. V. Loskutov K. N. Evtushenko A. A. 《Technical Physics》2019,64(1):27-33
Technical Physics - A method for creating a pressure gradient by pulsed injection of air into a large vacuum chamber for laboratory simulation of plasma phenomena in a vertically nonuniform... 相似文献