Search results for "Crystal"
showing 10 items of 22886 documents
Inter-crystal scatter in positron emission tomography: Identification techniques and effects on reconstructed images for AX-PET demonstrator
2012
La PET es una técnica de imagen en medicina nuclear que permite la visualización in-vivo y en 3D de procesos funcionales en seres vivos. Un escáner PET mide los rayos gamma producidos al aniquilarse un positrón, el cual es emitido por un radioisótopo inyectado al paciente. La eficiencia del sistema es una característica crucial de los escáneres PET de alta resolución dedicados a la imagen del cerebro o de animales pequeños con el fin de obtener una imagen más fiel o de reducir la actividad del radiotrazador, y por consiguiente, la dosis inyectada al paciente. El objetivo de este trabajo de investigación es mejorar la eficiencia y calidad de imagen de un prototipo de escáner PET axial (AX-PE…
CCDC 1972055: Experimental Crystal Structure Determination
2020
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 1972054: Experimental Crystal Structure Determination
2020
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
New high-pressure phase and equation of state of Ce2Zr2O8
2012
In this paper we report a new high-pressure rhombohedral phase of Ce2Zr2O8 observed from high-pressure angle-dispersive x-ray diffraction and Raman spectroscopy studies up to nearly 12 GPa. The ambient-pressure cubic phase of Ce2Zr2O8 transforms to a rhombohedral structure beyond 5 GPa with a feeble distortion in the lattice. Pressure evolution of unit-cell volume showed a change in compressibility above 5 GPa. The unit-cell parameters of the high-pressure rhombohedral phase at 12.1 GPa are ah = 14.6791(3) {\AA}, ch = 17.9421(5) {\AA}, V = 3348.1(1) {\AA}3. The structure relation between the parent cubic (P2_13) and rhombohedral (P3_2) phases were obtained by group-subgroup relations. All t…
Multifacial Recognition in Binary and Ternary Cocrystals from 5-Halouracil and Aminoazine Derivatives
2018
A systematic analysis using single crystal X-ray diffraction was performed to explore the role exerted by potential intercomponent proton-transfer reactions in the supramolecular structures of A–B cocrystals formed by 5-haloderivatives of uracil (A), coupled with 2-aminoadenine simulants (aminoazines, B). Twelve new heterodimers were synthesized in different stoichiometries and cocrystallized by solvent cogrinding followed by solution crystallization. In the binary cocrystals, uracil or 1-methyluracil with halide modification at the 5 position (F, Cl, Br, I) was coupled with amino-aromatic N-heterocycles (melamine, 2,4,6-triaminopyrimidine, 2,6-diaminopyridine) as a multivalent site for pyr…
Intramolecular Hydrogen Bond, Hirshfeld Analysis, AIM; DFT Studies of Pyran-2,4-dione Derivatives
2021
Intra and intermolecular interactions found in the developed crystals of the synthesized py-ron-2,4-dione derivatives play crucial rules in the molecular conformations and crystal stabili-ties, respectively. In this regard, Hirshfeld calculations were used to quantitatively analyze the different intermolecular interactions in the crystal structures of some functionalized py-ran-2,4-dione derivatives. The X-ray structure of pyran-2,4-dione derivative namely (3E,3′E)-3,3′-((ethane-1,2-diylbis(azanediyl))bis(phenylmethanylylidene))bis(6-phenyl-2H-pyran-2,4(3H)-dione) was determined. It crystallized in the monoclinic crystal system and C2/c space group with unit cell parameters: a = 14.0869(4) …
CCDC 1576743: Experimental Crystal Structure Determination
2019
Related Article: Arkalekha Mandal, Kari Rissanen, Prasenjit Mal|2019|CrystEngComm|21|4401|doi:10.1039/C9CE00561G
CCDC 1893191: Experimental Crystal Structure Determination
2019
Related Article: Esa Kukkonen, Henri Malinen, Matti Haukka, Jari Konu|2019|Cryst.Growth Des.|19|2434|doi:10.1021/acs.cgd.9b00119
2-(3,5-Dimethyl-1H-pyrazol-1-yl)-2-hydroxyimino-N0-[1-(pyridin-2-yl)ethylethylidene]
2012
In the title compound, C14H16N6O2, the dihedral angles formed by the mean plane of the acetohydrazide group [maximum deviation 0.0629 (12) A˚ ] with the pyrazole and pyridine rings are 81.62 (6) and 38.38 (4) respectively. In the crystal, molecules are connected by N—HO and O—HN hydrogen bonds into supramolecular chains extending parallel to the c-axis direction. peerReviewed
(E)-1-(Pyridin-4-yl)propan-1-one oxime
2016
The asymmetric unit of the title compound, C8H10N2O, contains two crystallographically independent molecules of slightly different conformation, which are linkedviaan intermolecular O—H...N hydrogen bond. The dihedral angle between the pyridine ring and the oxime plane of moleculeA[2.09 (19)°] is smaller than in moleculeB[16.50 (18)°].