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排序方式: 共有5975条查询结果,搜索用时 15 毫秒
1.
Physics of Atomic Nuclei - A model of dynamics with separate temperature feedback formed by average temperatures of the fuel and the coolant is constructed for the IBR-2M pulsed reactor of periodic... 相似文献
2.
Central European Journal of Operations Research - Many approaches have been designed to solve a stock portfolio selection problem. The aim of this paper is to provide a complex supporting tool for... 相似文献
3.
Ya-Shan Huang Yuan Xue Prof. Alvaro Muñoz-Castro Prof. Dr. Ivan A. Popov Prof. Dr. Zhong-Ming Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(62):e202202192
During the past two decades, single-atom-centered medium-sized germanium clusters [M@Gen] (M=transition metals, n>12) have been extensively explored, both from theoretical perspectives and experimental gas-phase syntheses. However, the actual structural arrangements of the Ge13 and Ge14 endohedral cages are still ambiguous and have long remained an unresolved problem for experimental implementation. In this work, we successfully synthesize 13-/14-vertex Ge clusters [Nb@Ge13]3− ( 1 ) and [Nb@Ge14]3− ( 2 ), which are structurally characterized and exhibit unprecedented topologies, neither classical deltahedra nor 3-connected polyhedral structures. Theoretical analysis indicates that the major stabilization of the Ge backbones arises due to the substantial interaction of Ge 4p-AOs with the endohedral Nb 4d-AOs through three/four-center two-electron bonds with an enhanced electron density accumulated over the shortest Nb−Ge13 contact in 1 . Low occupancies of the direct two-center two-electron (2c–2e) Nb−Ge and Ge−Ge σ bonds point to a considerable degree of electron delocalization over the Ge cages revealing their electron deficiency. 相似文献
4.
Technical Physics - The initial composition and chemical state of nanopowder primary particles obtained by grinding natural diamond and detonation synthesis have been studied by X-ray photoelectron... 相似文献
5.
Boyko K. M. Nikolaeva A. Yu. Bakunova A. K. Stekhanova T. N. Rakitina T. V. Popov V. O. Bezsudnova E. Yu. 《Crystallography Reports》2021,66(5):802-807
Crystallography Reports - Pyridoxal 5′-phosphate (PLP)-dependent transaminases catalyze the stereospecific amino-group transfer from an amino acid or amine to ketone or keto acid.... 相似文献
6.
Georgios Velkos Denis S. Krylov Kyle Kirkpatrick Lukas Spree Vasilii Dubrovin Bernd Büchner Stanislav M. Avdoshenko Valeriy Bezmelnitsyn Sean Davis Paul Faust James Duchamp Harry C. Dorn Alexey A. Popov 《Angewandte Chemie (International ed. in English)》2019,58(18):5891-5896
The azafullerene Tb2@C79N is found to be a single‐molecule magnet with a high 100‐s blocking temperature of magnetization of 24 K and large coercivity. Tb magnetic moments with an easy‐axis single‐ion magnetic anisotropy are strongly coupled by the unpaired spin of the single‐electron Tb?Tb bond. Relaxation of magnetization in Tb2@C79N below 15 K proceeds via quantum tunneling of magnetization with the characteristic time τQTM=16 462±1230 s. At higher temperature, relaxation follows the Orbach mechanism with a barrier of 757±4 K, corresponding to the excited states, in which one of the Tb spins is flipped. 相似文献
7.
Marianna V. Rodrigues Fbio S. Zanuzzo Joo Fernando A. Koch Carlos Alberto F. de Oliveira Petr Sima Vaclav Vetvicka 《Molecules (Basel, Switzerland)》2020,25(22)
Administration of β-glucans through various routes, including immersion, dietary inclusion, or injection, have been found to stimulate various facets of immune responses, such as resistance to infections and resistance to environmental stress. β-Glucans used as an immunomodulatory food supplement have been found beneficial in eliciting immunity in commercial aquaculture. Despite extensive research involving more than 3000 published studies, knowledge of the receptors involved in recognition of β-glucans, their downstream signaling, and overall mechanisms of action is still lacking. The aim of this review is to summarize and discuss what is currently known about of the use of β-glucans in fish. 相似文献
8.
Russian Physics Journal - Using the method of spectrally selective photorecording in a nanosecond temporal resolution, the distribution of neutral atoms and single- and double-charged gallium ions... 相似文献
9.
Olga Bakhanovich Dr. Petr Beier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(4):773-782
Organic α-fluorinated azidoalkanes appeared in the literature for the first time half a century ago. However, for a long time they remained undeveloped and were regarded as chemical curiosities. Recent advances in the preparation of α-fluorinated azidoalkanes as well as studies on their stability and reactivity opened up their broader synthetic potential for the preparation of valuable fluorinated and non-fluorinated compounds. 相似文献
10.
. N. Morozov I. N. Shcherbakov S. I. Levchenkov L. D. Popov 《Russian Journal of General Chemistry》2020,90(2):257-267
A potentially tridentate coordinating chelating ligand system, 1-phenyl-3-methylpyrazol-5-one ferrocenoylhydrazone, has been synthesized. Structure of the obtained ligand and its equilibrium forms in the solution has been elucidated from the data of elemental analysis, IR, electronic absorption and NMR (1H, 13C, and 15N NMR including 1H–1H COSY, 1H–1H NOESY, 1H–13C HSQC, 1H–13C HMBC, and 1H–15N HMBC 2D correlation techniques) spectroscopy as well as quantum chemistry methods. The reactions of 1-phenyl-3-methylpyrazol-5-one ferrocenoylhydrazone with selected transition metal ions have afforded metal chelates, their composition, the mode of coordination, and type of tautomeric form of the coordinated ligand being dependent on the metal nature. 相似文献