Search results for "Symbol"
showing 10 items of 7541 documents
Towards an efficient meshfree solver
2016
In this paper we focus on the enhancement in accuracy approximating a function and its derivatives via smoothed particle hydrodynamics. We discuss about improvements in the solution by reformulating the original method by means of the Taylor series expansion and by projecting with the kernel function and its derivatives. The accuracy of a function and its derivatives, up to a fixed order, can be simultaneously improved by assuming them as unknowns of a linear system. The improved formulation has been assessed with gridded and scattered data points distribution and the convergence has been analyzed referring to a case study in a 2D domain.
Constraining the pass-band of future space-based coronagraphs for observations of solar eruptions in the FeXIV 530.3 nm “green line”
2017
This research has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 647214) and from the UK Science and Technology Facilities Council. Observations of the solar corona in the FeXIV 530.3 nm “green line” have been very important in the past, and are planned for future coronagraphs on-board forthcoming space missions such as PROBA-3 and Aditya. For these instruments, a very important parameter to be optimized is the spectral width of the band-pass filter to be centred over the “green line”. Focusing on solar eruptions, motions occurring along the line of sight will Doppler shift the line prof…
Motyw "wieśnej rycerki", czyli światowe sprawy pani wrony w twórczości Mikołaja Reja
2020
The subject of the article is the symbolism of the crow considered against the background of the old encyclopedic tradition. The comparison of erudite content in the field of natural history with fragments of Mikołaj Rej’s works brings interesting insights. It turns out that the crow occupies a prominent place in the allegorical zoo of Reja. Allegoric interpretations related to the theme of this bird in Nagłowiczanin’s works do not go beyond the traditionally accepted interpretations. Unpleasant croaking, raven exterior, or even the crow’s thieving habits did not deprive her of universal friendliness. Already in Aesop’s fairy tales you can admire the extraordinary cunning and thrift of this…
Polymorphism and versatile solvate formation of thiophanate-methyl
2009
The polymorphism of a fungicide, thiophanate-methyl (TM), was investigated with conventional solvent screening methods. Two polymorphs, the thermodynamically most stable form I and the less stable form II, were found. TM was also found to crystallize as a plethora of different solvates which produced mostly form II upon desolvation. The structures of form I and form II and the fourteen discovered solvates were solved by single crystal X-ray diffraction. The most stable forms were further characterized by powder diffraction, thermoanalytical (TG/DTA, DSC and thermomicroscopy) and spectroscopic (IR, Raman, ¹³C CP/MAS NMR) methods. peerReviewed
3,5-Dimethoxyphenyl 4-methylbenzenesulfonate
2017
Molecules of the title compound, C15H16O5S, are composed of a 3,5-dimethoxyphenyl moiety substituted with a toluene-4-sulfonate group. The dihedral angle between two aromatic rings is 57.23 (4)°. In the crystal, molecules are connected by weak C—H...O hydrogen bonds and S...O van der Waals interactions.
Crystal structure of 1-(2-fluorobenzoyl)-2,7-dimethoxynaphthalene
2014
The asymmetric unit of the compound contains two independent conformers. Each conformer is stacked along the a axis to form columns through van der Waals interactions only.
Bis(4,6-di-tert-butyl-2-{N-[4-(diethylamino)phenyl]carboximidoyl}phenolato)cobalt(II)
2017
In the title complex, [Co(C25H35N2O)2], the cobalt(II) atom has a distorted tetrahedral geometry provided by pairs of O and N atoms. The dihedral angles between the benzene rings of the same ligand are 52.39 (9) and 34.96 (9)°. The molecular structure is stabilized by weak intramolecular C—H...O hydrogen bonds. The crystal packing is stabilized mainly by van der Waals forces. The structure contains a solvent-accessible void of 276 Å3which was treated using the SQUEEZE routine fromPLATON[Spek (2015).Acta Cryst.C71, 9–18]. The methyl C atoms of thetert-butyl groups are rotationally disordered, with site occupancies of 0.802 (3) and 0.548 (9) for the major components and 0.198 (3) and 0.452 (9…
Stabilisation of Exotic Tribromide (Br3−) Anions via Supramolecular Interaction with A Tosylated Macrocyclic Pyridinophane. A Serendipitous Case.
2020
Tetraaza-macrocyclic pyridinophane L-Ts, decorated with a p-toluenesulfonyl (tosyl
Crystal structure and absolute configuration of (3aR,3′aR,7aS,7′aS)-2,2,2′,2′-tetramethyl-3a,6,7,7a,3′a,6′,7′,7′a-octahydro-4,4′-bi[1,3-benzodioxolyl…
2017
The absolute configuration,i.e.(3aR,3′aR,7aS,7′aS), of the title compound, C18H26O4, synthesizedviaa palladium-catalyzed homocoupling reaction, was determined on the basis of the synthetic pathway and was confirmed by X-ray diffraction. The homocoupled molecule is formed by two chemically identical moieties built up from two five- and six-membered fused rings. The supramolecular assembly is controlled mainly by C—H...O interactions that lead to the formation of hydrogen-bonded chains of molecules along the [001] direction, while weak dipolar interactions and van der Waals forces hold the chains together in the crystal structure.
1,1′-(Diphosphene-1,2-diyl)bis(2,2,6,6-tetramethylpiperidine)
2017
The title compound, C18H36N2P2, crystallizes in the triclinic space groupP-1 with two independent molecules in the asymmetric unit. Both molecules adopt atransconfiguration of the tetramethylpiperidine units along the P=P axis. The crystal packing is stabilized only by van der Waals interactions.