Search results for "effect"
showing 10 items of 9072 documents
Studies in organic mass spectrometry. Part 23. Role of the aroyl group on the competitive fragmentation reactions of the molecular ion of aroylanilid…
1999
The 70 eV and mass-analysed ion kinetic energy (MIKE) spectra of some thiophenecarboxanilides and benzoylanilides (1–10) have been compared in order to investigate the role of the aroyl (or heteroaroyl) moiety on the abundance of the competitive fragmentation reactions occurring in their molecular ions (amide–bond cleavage and phenol radical ion formation). It has been shown that the electron ionisation induced decompositions with high (70 eV) and low (MIKE) internal energy excess are qualitatively similar, but remarkable quantitative differences have been observed that can be accounted for in terms of the different effectiveness in the transmission of electronic effects of substituents in …
Classical and reverse substituent effects in meta- and para-substituted nitrobenzene derivatives
2017
Electron-accepting properties of the nitro group were studied in a series of meta- and para-X-substituted nitrobenzene derivatives (X = NMe2, NH2, OH, OMe, CH3, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, COCl, NO2, NO). For this purpose Hammett-like approaches were applied based on quantum chemistry modeling; the B3LYP/6-311++ G(d,p) method was used. The substituent effect (SE) was characterized by the mutually interrelated descriptors: the charge of the substituent active region, cSAR(X), and substituent effect stabilization energy, SESE, as well as substituent constants, σ. Classical SE is realized by dependences of the structural parameters of the nitro group (ONO angle and NO bond lengt…
Substituent effects on the mechanism changeover in a multipathway reaction: A model for the behavior of biological systems?
2009
By studying the rearrangement in dioxane/water of a series of (Z)-arylhydrazones of 5-amino-3- benzoyl-1,2,4-oxadiazole (1a-k) into the relevant (2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas (2a-k) in a wide range of pS + (an operational scale of proton concentration in the mixed solvent used; dioxane/water, 1:1, v:v), the occurrence of three different reaction pathways (specific-acid- catalyzed, uncatalyzed, and general-base-catalyzed) for the relevant SNi process has been recently enlightened. The significantly different substituent effects on the three pathways cause some crossovers in the log kA,R versus pS + plots. Both the pS + value at which the crossover occurs and the width of the u…
Effects of Repeated Sprint Training in Hypoxia on Physical Performance Among Athletes : A Systematic Review
2021
Repeated sprint training in hypoxia (RSH) represents an innovative method in the process of development and improvement of physical performance among athletes. However, there is less scientific data on this topic. The purpose of this systematic review was to investigate the effect of RSH method on motor abilities and performance among athletes, obtain new information, and expand the already known conclusions. The data search was performed of 4 electronic databases for the years 2000-2021 May as follows: Google Scholar, PubMed, Web of Science, and ResearchGate. This search with English language restriction was made by using the following terms, individually/combination: "repeated sprint abil…
Odd triplet superconductivity induced by a moving condensate
2020
It has been commonly accepted that a magnetic field suppresses superconductivity by inducing the ordered motion of Cooper pairs. We demonstrate that a magnetic field can instead provide a generation of superconducting correlations by inducing the motion of a superconducting condensate. This effect arises in superconductor/ferromagnet heterostructures in the presence of Rashba spin-orbital coupling. We predict the odd-frequency spin-triplet superconducting correlations called the Berezinskii order to be switched on at large distances from the superconductor/ferromagnet interface by the application of a magnetic field. This is shown to result in the unusual behavior of Josephson effect and lo…
Quantum fluctuations in superconducting nanostructures
2014
Modern nanofabrication technology enableTfabrication of very narrow quasi-1-dimensional superconducting nanowires demonstrating finite resistivity within the range of experimentally obtainable temperatures. The observations were reported in ∼10 nm nanowires of certain superconducting materials. The effect has been associated with quantum phase slip process - the particular manifestation of quantum fluctuations of the order p arameter. In titanium, the phenomenon can be observed already at dimensions ∼35 nm where the fabrication is well reproducible and the dimensions of samples can be characterized with high accuracy. We have performed systematic study of the size dependence of transport pr…
Virtualization of work in global supply chains
2016
ABSTRACT. Background: The paper is devoted to the notion and benefits of implementing virtual work in global supply chains. Virtual work must be understood as an intentional activity of a human being, aimed at rendering services (tangible and intangible), by means of ITC tools, performed in a distance from the traditional place of work, in a mobile manner. The empirical research were conducted on the basis of 4 case studies of global leaders of supply chains, which in accordance with M. Fisher's classification, represent two types. The case studies confirmed the positive influence of virtual work both in effective and flexible supply chains. Favourable market and technological conditions an…
Virtualization of work in global supply chains
2016
Background: The paper is devoted to the notion and benefits of implementing virtual work in global supply chains. Virtual work must be understood as an intentional activity of a human being, aimed at rendering services (tangible and intangible), by means of ITC tools, performed in a distance from the traditional place of work, in a mobile manner. The empirical research were conducted on the basis of 4 case studies of global leaders of supply chains, which in accordance with M. Fisher's classification, represent two types. The case studies confirmed the positive influence of virtual work both in effective and flexible supply chains. Favourable market and technological conditions and incr…
Coupling the Higgs mode and ferromagnetic resonance in spin-split superconductors with Rashba spin-orbit coupling
2022
We show that the Higgs mode of superconductors can couple with spin dynamics in the presence of a static spin-splitting field and Rashba spin-orbit coupling. The Higgs-spin coupling dramatically modifies the spin susceptibility near the superconducting critical temperature and consequently enhances the spin pumping effect in a ferromagnetic insulator/superconductor bilayer system. We show that this effect can be detected by measuring the magnon transmission rate and the magnon-induced voltage generated by the inverse spin Hall effect.
Topological polarization, dual invariants, and surface flat band in crystalline insulators
2020
We describe a three-dimensional crystalline topological insulator (TI) phase of matter that exhibits spontaneous polarization. This polarization results from the presence of (approximately) flat bands on the surface of such TIs. These flat bands are a consequence of the bulk-boundary correspondence of polarized topological media, and contrary to related nodal line semimetal phases also containing surface flat bands, they span the entire surface Brillouin zone. We also present an example Hamiltonian exhibiting a Lifshitz transition from the nodal line phase to the TI phase with polarization. Utilizing elasticity tetrads, we show a complete classification of 3D crystalline TI phases and invar…