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排序方式: 共有326条查询结果,搜索用时 15 毫秒
1.
Journal of Mathematical Chemistry - The Sombor index was introduced in 2020, and was soon followed by a remarkably large number of studies, both chemical and mathematical. In this review we collect... 相似文献
2.
In this work we study the homotopy theory of coherent group actions from a global point of view, where we allow both the group and the space acted upon to vary. Using the model of Segal group actions and the model categorical Grothendieck construction we construct a model category encompassing all Segal group actions simultaneously. We then prove a global rectification result in this setting. We proceed to develop a general truncation theory for the model-categorical Grothendieck construction and apply it to the case of Segal group actions. We give a simple characterization of n-truncated Segal group actions and show that every Segal group action admits a convergent Postnikov tower built out of its n-truncations. 相似文献
3.
The Kakutani–Bebutov Theorem (1968) states that any compact metric real flow whose fixed point set is homeomorphic to a subset of embeds into the Bebutov flow, the -shift on . An interesting fact is that this universal space is a function space. However, it is not compact, nor locally compact. We construct an explicit countable product of compact subspaces of the Bebutov flow which is a universal space for all compact metric real flows, with no restriction; namely, into which any compact metric real flow embeds. The result is compared to previously known universal spaces. 相似文献
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5.
A new concept of an X-ray brachytherapy setup based on the use of fluorescence from a secondary target placed at the tip of an implantable needle is proposed. Spatial dose-rate distributions for four combinations of secondary target materials and shapes are calculated by the Monte-Carlo method. 相似文献
6.
The Soreq Applied Research Accelerator Facility (SARAF): Overview,research programs and future plans
Israel Mardor Ofer Aviv Marilena Avrigeanu Dan Berkovits Adi Dahan Timo Dickel Ilan Eliyahu Moshe Gai Inbal Gavish-Segev Shlomi Halfon Michael Hass Tsviki Hirsh Boaz Kaiser Daniel Kijel Arik Kreisel Yonatan Mishnayot Ish Mukul Ben Ohayon Michael Paul Amichay Perry Hitesh Rahangdale Jacob Rodnizki Guy Ron Revital Sasson-Zukran Asher Shor Ido Silverman Moshe Tessler Sergey Vaintraub Leo Weissman 《The European Physical Journal A - Hadrons and Nuclei》2018,54(5):91
7.
Yonatan Hamo Michal Lahav Milko E. van der Boom 《Angewandte Chemie (International ed. in English)》2020,59(7):2612-2617
We demonstrate controlled charge trapping and release, accompanied by multiple color changes in a metallo‐organic bilayer. The dual functionality of the metallo‐organic materials provides fundamental insight into the metal‐mediated electron transport pathways. The electrochemical processes are visualized by distinct, four color‐to‐color transitions: red, transparent, orange, and brown. The bilayer is composed of two elements: 1) a nanoscale gate consisting of a layer of well‐defined polypyridyl ruthenium complexes bound to a flexible transparent electrode, and 2) a charge storage layer consisting of isostructural iron complexes attached to the surface of the gate. This gate mediates or blocks electron transport in response to an applied voltage. The charge storage and release depend on the oxidation state of the layer of ruthenium complexes (=gate). Combining electrochemistry with optical data revealed mechanistic information: the brown coloration of the bilayer directly relates to the formation of intermediate ruthenium species, providing evidence for catalytic positive charge release mediated through the gate. 相似文献
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9.
S. Markovi? S. Radenkovi? Z. Markovi? I. Gutman 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(13):2368-2372
The diradical character of zethrenes was investigated using a symmetry-broken UB3LYP/6-311G(d,p) method. The number of hexagons in the investigated molecules ranges from 6 to 12. It was found that all zethrenes are singlet
diradicals, whose diradical character increases with the increasing size of the molecules. A singlet diradical structure provides
a possibility for an electron pair to occupy different parts of space, and allows for achieving aromatic stabilization. It
can be predicted, on the basis of the singlet-triplet values, that even higher zethrenes will be singlet, but not triplet
molecules. 相似文献
10.
E. A. Sozontov V. V. Safronov G. Gutman 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(2):199-202
An experiment confirming the possibility of extracting a narrow energy band from a wide spectrum produced by a compact electron
linear accelerator with a thin transmission anode is described. A flat crystal of pyrolytic graphite was used as a monochromator. 相似文献