Search results for " matter"

Spin caloric transport from density-functional theory

2019

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for information technology, known by the synonym spin caloritronics. Within the framework of ab initio theory, new tools are being developed to provide an additional understanding of these phenomena in realistic materials, accounting for the complexity of the electronic structure without adjustable parameters. Here, we review this progress, summarising the principles of the density-functional-based approaches in the field and presenting a number of application highlights. Our discussion includes th…

Postępowanie cywilne w sprawach gospodarczych – powrót do przeszłości czy nowa jakość?

2021

Celem artykułu jest omówienie wybranych instytucji postępowania odrębnego w sprawach gospodarczych. Nowe przepisy po części recypują regulacje obowiązujące do 1 maja 2012 r. Przepisy te w znacznym stopniu stanowią także nowe rozwiązania. Głównym celem unormowania postępowania odrębnego w sprawach gospodarczych jest przyspieszenie tych postępowań

X-ray emission from the old CTTS MP Muscae

2007

We study the properties of X-ray emitting plasma of MP Mus, an old classical T Tauri star. XMM-Newton/RGS spectra allow us to measure the plasma electron density, which probes whether X-ray emission is produced in the accretion process. X-ray emission from MP Mus originates from high density cool plasma but a hot flaring component is also present, suggesting that both coronal magnetic activity and accretion contribute to the observed X-ray emission. From the soft part of the X-ray emission from MP Mus, mostly produced by plasma heated in the accretion shock, we derive the accretion parameters and the characteristics of the shock-heated plasma.

X-ray emission from an adolescent classical T Tauri star

2007

Photoluminescence and Electron Spin Resonance of Silicon Dioxide Crystal with Rutile Structure (Stishovite)

2018

This work was supported by ERANET MYND. Also, financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/2 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. The authors express our gratitude to R.I. Mashkovtsev for help in ESR signal interpretation. The authors are appreciative to T.I. Dyuzheva, L.M. Lityagina, N.A. Bendeliani for stishovite single crystals and to K. Hubner and H.-J. Fitting for stishovite powder of Barringer Meteor Crater.

The effect of defect location on coating fragmentation patterns under biaxial tension

2005

Fragmentation of a coating possessing orthogonal preferential crack propagation directions is modeled for equibiaxial tensile loading. Two plausible cracking scenarios are compared, caused by flaws randomly distributed over the area of the coating or along the coating fragment edges. The two fragmentation scenarios considered are shown to yield qualitatively different fragment patterns.

Classroom discussions: Possibilities and limitations for democratic classroom practices

2017

Are students offered possibilities to experience democratic practice in classrooms? Using an analysis of empirical data from classroom discussions in lower secondary school, this article identifies and explores two different types of classroom discussions which give students different positions: a conversation in which students are positioned as ‘poll respondents’, and a more deliberative conversation which positions students as learning debaters. The two forms of classroom discussions are discussed due to the way they give different meaning to democracy, and due to whether the student positions in the classrooms imply contribution to the subject matter and what is considered valuable knowl…

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…

Copper-hydride nanoclusters with enhanced stability by N-heterocyclic carbenes

2021

AbstractCopper-hydrides have been intensively studied for a long time due to their utilization in a variety of technologically important chemical transformations. Nevertheless, poor stability of the species severely hinders its isolation, storage and operation, which is worse for nano-sized ones. We report here an unprecedented strategy to access to ultrastable copper-hydride nanoclusters (NCs), namely, using bidentate N-heterocyclic carbenes as stabilizing ligands in addition to thiolates. In this work, a simple synthetic protocol was developed to synthesize the first large copper-hydride nanoclusters (NCs) stabilized by N-heterocyclic carbenes (NHCs). The NC, with the formula of Cu31(RS)2…

Ray optics behavior of flux avalanche propagation in superconducting films

2015

Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a $0.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ thick metal layer, the refractive index was close to $n=1.4$. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal …