Search results for "atomic structure"
showing 9 items of 9 documents
Ab initio calculations of pure and Co+2-doped MgF2 crystals
2020
This research was partly supported by the Kazakhstan Science Project № AP05134367«Synthesis of nanocrystals in track templates of SiO2/Si for sensory, nano- and optoelectronic applications», as well as by Latvian Research Council project lzp-2018/1-0214. Calculations were performed on Super Cluster (LASC) in the Institute of Solid State Physics (ISSP) of the University of Latvia. Authors are indebted to S. Piskunov for stimulating discussions.
Evidence of noncentrosymmetry of human tooth hydroxyapatite crystals
2014
Herein, we investigate human single hydroxyapatite crystals (enamel and dentine) by convergent-beam electron diffraction (CBED) and automated electron-diffraction tomography (ADT). The CBED pattern shows the absence of the mirror plane perpendicular to the c axis leading to the P63 space group instead of the P63 /m space group considered for larger-scale crystals, this is confirmed by ADT. This experimental evidence is of prime importance for understanding the morphogenesis and the architectural organization of calcified tissues.
Exploring the atomic structure of 1.8 nm monolayer-protected gold clusters with aberration-corrected STEM
2017
Abstract Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au 144 (SCH 2 CH 2 Ph) 60 provided by two different research groups. The MP Au clusters were “weighed” by the atom counting method, based on their integrated intensities in the high …
New Developments in the Production and Research of Actinide Elements
2022
Atoms 10(2), 61 (2022). doi:10.3390/atoms10020061
Phase Stability of Lanthanum Orthovanadate at High Pressure
2016
The journal of physical chemistry / C 120(25), 13749 - 13762(2016). doi:10.1021/acs.jpcc.6b04782
Density functional/molecular dynamics simulations of phase-change materials
2013
Local Structure Studies of Ti for SrTi16O3 and SrTi18O3 by Advanced X-ray Absorption Spectroscopy Data Analysis
2015
Strontium titanate is a model quantum paraelectric in which in the region of dominating quantum statistics the ferroelectric instability is inhibited due to nearly complete compensation of the harmonic contribution into ferroelectric soft mode frequency by the zero-point motion contribution. The enhancement of atomic masses by the substitution of 18O for 16O decreases the zero-point atomic motion and low-T ferroelectricity in SrTi18O3 is realized. In this study we report on the local structure of Ti in SrTi16O3 and SrTi18O3 by Ti K-edge extended x-ray absorption fine structure measurements in temperature range 6 – 300 K.
ODS tērauda izejmateriālu lokālās struktūras analīze izmantojot Ti un Y K-malas rentgenabsorbcijas spektroskopiju
2017
Šajā darbā tika izmantota rentgenstaru absorbcijas spektru analīze oksīdu stiprinātam tēraudam (ODS), kas ir perspektīvs materiāls dažādās jomās, piemēram, saules elektrostacijās, reaktīvos dzinējos, ķīmiskos reaktoros un kodolreaktoros, jo materiālam piemīt tādas īpašības kā laba siltumvadītspēja un zema termiskās izplešanās apvienojumā ar augstu temperatūras izturību, korozijas un radiācijas pretestību. Darbā tiek iegūta informācija par ar dažādām metodēm izgatavotu ODS tēraudu lokālās atomārās struktūras izmaiņu ap itrija (Y) un titāna (Ti) atomiem, analizējot Y un Ti absorbcijas K-malu.
ODS tērauda izejmateriālu lokālās struktūras analīze, izmantojot rentgenabsorbcijas spektroskopiju
2015
Oksīdu stiprināts tērauds (ODS) ir perspektīvs kodolsintēzes reaktoru materiāls, kuram ir lieliska siltumvadītspēja un zema termiskās izplešanās, apvienojumā ar augstu temperatūras izturību, korozijas un radiācijas pretestību. Tamdēļ šo materiālu var izmantot arī daudzos citos pielietojumos, piemēram, saules elektrostacijās, reaktīvos dzinējos, ķīmiskos reaktoros, kā arī ūdeņraža ražošanā. Šajā darbā ar rentgenabsorbcijas spektroskopijas metodi tika analizētas ferīta un austentisko ODS tēraudu lokālās atomārās struktūras izmaiņas ap dzelzs (Fe) un hroma (Cr) atomiem dažādos tēraudu izgatavošanas posmos, analizējot Fe un Cr absorbcijas K-malas spektrus.