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Ekstrakcijas-pirolītiskās metodes izmantošana nanokristāliska Gd2O3 pulveru un plāno kārtiņu iegūšanai
2019
Ekstrakcijas-pirolītiskās metodes izmantošana nanokristāliska gadolīnija oksīda pulveru un plāno kārtiņu iegūšanai. Burve R., darba vadītāji vadošā pētniece, Dr. chem. Serga V. un asoc. prof., Dr. chem. Švirksts J. Bakalaura darbs, 59 lappuses, 24 attēli, 6 tabulas, 59 literatūras avoti, 18 pielikumi. Latviešu valodā. Darbā apkopota informācija par gadolīnija (III) oksīda īpašībām, izmantošanas iespējām un iegūšanas metodēm. Darba ietvaros ar ekstrakcijas-pirolītisko metodi (EPM) iegūti gadolīnija (III) oksīda nanokristāliskie pulveri un plānās kārtiņās uz dažāda veida stikla substrātiem. Tika izpētītas iegūtā prekursora termiskās īpašības, izmantojot termogravimetrijas un diferenciālās ske…
Zvaigžņotā Debess: 2011, Pavasaris (211)
2011
Contents: “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: A.Alksnis. XIV General Assembly of the International Astronomical Union (abridged) ; H.Strods. Jaunlaicene’s Watchmaker (abridged) ; I.Daube. At the Radioastrophysical Observatory of the Latvian Academy of Sciences (abridged). 50 YEARS SINCE GAGARIN’S SPACE FLIGHT: R.Misa. Dream about Cosmos ; A.Zalcmane. Konstantin Tsiolkovsky Astronautics Museum in Kaluga; E.Bērziņa. Outer Space in Pauls Stradins Museum of History of Medicine. NEWS: A.Alksnis. Different Faces of Whirpool Galaxy ; A.Alksnis. The Kleopatra’s Trio and other Minor Planets Groups. SPACE RESEARCH and EXPLORATION: V.Kalniņš. NASA Preparing Solar Probe Plus to Plunge into Sun's Atmos…
Pēdējais Pinguicula alpina L. paraugs no Staburaga
1961
LU Muzeja Botānikas un mikoloģiju kolekciju herbārijā glabājas vairāki alpu kreimules herbāriji, kas ievākti gan Igaunijā, gan Latvijā. Auga vienīgā dabiskā augtene Latvijā bija Staburags, kas tika apludināts līdz ar HES būvniecību. Vēlākos gados tā bija atrodama arī Raunas Staburagā. Alpu kreimules paraugi LU Muzejā glabājas Herbarium Latvicum (RIG II), Herbarium Balticum (RIG I), Herbarium Lakshewitzi (RIG III) un Jāņa Ilstera herbārijā. Herbarium Latvicum glabājas pēdējais uz Staburaga Botāniķes Gaidas Ābeles (dz. 1931. gadā) ievāktais paraugs.
New data on the evolution of Mikrotia (Muridae, Rodentia) in the Late Miocene of Gargano (Apulia, Italy).
2014
Litorāles mikrobiotopu ietekme uz Pierīgas brūnūdens ezeru makrozoobentosa sabiedrībām
2019
Maģistra darba “Litorāles mikrobiotopu ietekme uz Pierīgas brūnūdens ezeru makrozoobentosa sabiedrībām” izstrāde un materiālu ievākšana notika (no 17.07.17. līdz 25.05.18.) četros Garkalnes novada ezeros – Līņezerā, Piekūnītī, Maku ezerā un Lielajā Jūgezerā. Analizējot iegūtos rezultātus var secināt, ka zoobentosa organismi visvairāk piesaistīti mikrobiotopiem ar ūdensaugiem un dūņainu grunti. Pārējos mikrobiotopos zoobentosa indivīdu un sugu skaits ir ievērojami mazāks apstiprinot izvirzīto hipotēzi. Ezeru paraugos tika konstatēti 14 dažādi makrozoobentosa taksoni. Visbiežāk pārstāvētās kārtas - vaboles un blaktis. Visi pētāmie ezeri pieskaitāmi brūnūdens ezeru tipam, augu sugu, grunts vei…
Synthesis, X-ray Structure, Conformational Analysis, and DFT Studies of a Giant s-Triazine bis-Schiff Base
2021
The current work involves the synthesis of 2,2′-(6-(piperidin-1-yl)-1,3,5-triazine-2,4-diyl)bis(hydrazin-2-yl-1-ylidene))bis(methanylylidene))diphenol 4, characterization, and the DFT studies of the reported compound. The crystal unit cell parameters of 4 are a = 8.1139(2) Å, b = 11.2637(2) Å, c = 45.7836(8) Å. The unit cell volume is 4184.28(15) Å3 and Z = 4. It crystallized in the orthorhombic crystal system and Pbca space group. The O…H, N…H, C…H, H…H and C…C intermolecular contacts which affect the crystal stability were quantitatively analyzed using Hirshfeld calculations. Their percentages were calculated to be 9.8, 15.8, 23.7, 46.4, and 1.6% from the whole contacts occurred in the cr…
Synthesis and X-ray Crystal Structure of New Substituted 3-4′-Bipyrazole Derivatives. Hirshfeld Analysis, DFT and NBO Studies
2021
A new compounds named 3-4′-bipyrazoles 2 and 3 were synthesized in high chemical yield from a reaction of pyran-2,4-diketone 1 with aryl hydrazines under thermal conditions in MeOH. Compound 2 was unambiguously confirmed by single-crystal X-ray analysis. It crystalizes in a triclinic crystal system and space group P-1. Its crystal structure was found to be in good agreement with the spectral characterizations. With the aid of Hirshfeld calculations, the H…H (54.8–55.3%) and H…C (28.3–29.2%) intermolecular contacts are the most dominant, while the O…H (5.8–6.5%), N…H (3.8–4.6%) and C…C (3.0–4.9%) are less dominant. The compound has a polar nature with a net dipole moment of 6.388 Debye. The …
Strong chromatic index of products of graphs
2007
Graphs and Algorithms
Geometric inequivalence of metric and Palatini formulations of General Relativity
2020
Projective invariance is a symmetry of the Palatini version of General Relativity which is not present in the metric formulation. The fact that the Riemann tensor changes nontrivially under projective transformations implies that, unlike in the usual metric approach, in the Palatini formulation this tensor is subject to a gauge freedom, which allows some ambiguities even in its scalar contractions. In this sense, we show that for the Schwarzschild solution there exists a projective gauge in which the (affine) Kretschmann scalar, K≡R R , can be set to vanish everywhere. This puts forward that the divergence of curvature scalars may, in some cases, be avoided by a gauge transformation of the …
The gene encoding the transcriptional repressor BERF-1 maps to a region of conserved synteny on mouse chromosome 16 and human chromosome 3 and a rela…
1999
We have recently identified and characterized a Kruppel-like zinc finger protein (BERF-1), that functions as a repressor of β enolase gene transcription. By interspecific backcross analysis the gene encoding BERF-1 was localized 4.7 cM proximal to the <i>Mtv6</i> locus on mouse chromosome 16, and an isolated pseudogene was localized to mouse chromosome 8, about 5.3 cM distal to the D8Mit4 marker. Nucleotide sequence identity and chomosome location indicate that the gene encoding BERF-1 is the mouse homologue (<i>Zfp148</i>) of ZNF148 localized to human chromosome 3q21, a common translocation site in acute myeloid leukemia patients.