RE(Y, Er, Gd, La, Nd, Sm, Dy)-doped SrBPO5 colorful phosphors: Definition of structural unit cell parameters and optical properties

Optik ◽  
2017 ◽  
Vol 139 ◽  
pp. 265-271 ◽  
Author(s):  
G. Çelik Gül ◽  
F. Kurtuluş
2019 ◽  
Vol 1 (1) ◽  
pp. 147-153 ◽  
Author(s):  
Christophe Tenailleau ◽  
Sigalit Aharon ◽  
Bat-El Cohen ◽  
Lioz Etgar

In this work, we performed a detailed study of the phase transformations and structural unit cell parameters of CsPbBr3 nanoparticles (NPs) and thin films.


2021 ◽  
pp. 5-31
Author(s):  
A.V. Kasatkin ◽  
S.Yu. Stepanov ◽  
M.V. Tsyganko ◽  
R. Skoda ◽  
F. Nestola ◽  
...  

This is a fnal paper in a series of publications devoted to the mineralogy of the Vorontsovskoe gold deposit in the Northern Urals. The article reports on oxygen compounds (oxyhalides, oxides, hydroxides, carbonates, sulfates, tungstates, phosphates, arsenates and silicates) of the Vorontsovskoe deposit, their chemical composition and, for selected minerals, unit-cell parameters and optical properties. Armenite, claudetite, ramsdellite, hingganite-(Nd) and chapmanite are found for the frst time in Russian Federation. As a conclusion for the entire series of publications, the general features of mineralogy of the Vorontsovskoe deposit are discussed, thanks to which it is considered as a unique mineral locality not only in Urals but in general in Russia.


Author(s):  
G. Borley ◽  
M. T. Frost

SummaryNine ferrohastingsites from the Younger Granites of Northern Nigeria and five from the nepheline-bearing rocks in the Marangudzi complex of Southern Rhodesia have been analysed chemically and their optical properties and unit-cell parameters determined.All the minerals have compositions that can be expressed by the formula NaCa2(Fe″Mg)4Fe‴Al2Si6O22(OH)2, but the Nigerian minerals differ from those of Marangudzi in their lower alumina contents, generally greater degree of iron enrichment, lower potassium, and more variable fluorine contents. These differences are considered to reflect the differences in composition of their respective parent rocks. The compositional similarities between some hastingsites and barkevikite are commented upon and the pleochroism of barkevikite is briefly discussed.Refractive indices of the analysed hastingsites have been plotted on the optical curves of Tröger. It is suggested that such curves are of limited use and that variations in unit-cell parameters might be a more useful method of determining the iron contents of hastingsites.The variation in cell parameters with variation in chemical composition of the analysed minerals is also discussed.


1987 ◽  
Vol 51 (363) ◽  
pp. 709-714 ◽  
Author(s):  
Kanenori Suwa ◽  
Masaki Enami ◽  
Tatsuro Horiuchi

AbstractChlorine-rich potassium hastingsite occurs in a calcareous pegmatite, a replacement zone and an amphibolite lens within hornblende gneiss on West Ongul Island, Lützow-Holm Bay, East Antarctica. The amphibolite lens and hornblende gneiss were metamorphosed to the kyanite-sillimanite grade of the granulite facies during Proterozoic metamorphism. Chemical analysis (3.27 wt.% Cl), unit cell parameters and optical properties of the Cl-rich potassium hastingsite are given. Cl-rich (> 3 wt.%) calcic amphiboles reported from various rock types are mostly more than 0.9 in (Na+ K) content, more than 0.4 in K/(Na + K) ratio, more than 0.75 in Fe2+/(Fe2++ Mg + Mn) ratio and more than 1.9 in AlIVcontent (total iron as FeO and O = 23). The unit cell volume of Cl-rich hastingsite is distinctly larger than that of Cl-poor hastingsite.


Author(s):  
I.N. Yadhikov ◽  
S.K. Maksimov

Convergent beam electron diffraction (CBED) is widely used as a microanalysis tool. By the relative position of HOLZ-lines (Higher Order Laue Zone) in CBED-patterns one can determine the unit cell parameters with a high accuracy up to 0.1%. For this purpose, maps of HOLZ-lines are simulated with the help of a computer so that the best matching of maps with experimental CBED-pattern should be reached. In maps, HOLZ-lines are approximated, as a rule, by straight lines. The actual HOLZ-lines, however, are different from the straights. If we decrease accelerating voltage, the difference is increased and, thus, the accuracy of the unit cell parameters determination by the method becomes lower.To improve the accuracy of measurements it is necessary to give up the HOLZ-lines substitution by the straights. According to the kinematical theory a HOLZ-line is merely a fragment of ellipse arc described by the parametric equationwith arc corresponding to change of β parameter from -90° to +90°, wherevector, h - the distance between Laue zones, g - the value of the reciprocal lattice vector, g‖ - the value of the reciprocal lattice vector projection on zero Laue zone.


Author(s):  
Gunnel Karlsson ◽  
Jan-Olov Bovin ◽  
Michael Bosma

RuBisCO (D-ribulose-l,5-biphosphate carboxylase/oxygenase) is the most aboundant enzyme in the plant cell and it catalyses the key carboxylation reaction of photosynthetic carbon fixation, but also the competing oxygenase reaction of photorespiation. In vitro crystallized RuBisCO has been studied earlier but this investigation concerns in vivo existance of RuBisCO crystals in anthers and leaves ofsugarbeets. For the identification of in vivo protein crystals it is important to be able to determinethe unit cell of cytochemically identified crystals in the same image. In order to obtain the best combination of optimal contrast and resolution we have studied different staining and electron accelerating voltages. It is known that embedding and sectioning can cause deformation and obscure the unit cell parameters.


2021 ◽  
Vol 62 (5) ◽  
Author(s):  
П.C. Серебренникова ◽  
В.Ю. Комаров ◽  
А.С. Сухих ◽  
С.А. Громилов

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