Search results for "GST"

Thermoactivated spectroscopy of heterovalent impurity traps in CdWO4

1995

Abstract Recombination luminescence emission spectra, TSL and trap spectra estimated by fractional glow technique (FGT), in nominally pure and Li-, Bi- and Ho-doped CdWO4, crystals are reported. According to the investigations by FGT heterovalent impurities Li, Bi and Ho causes localized electronic states which act as traps for charge carriers. It is shown that TSL results in emission of known blue-green luminescence band by emptying of the Li+-related traps in CdWO4-Li and yellow luminescence band by emptying of the Bi3+-related traps in CdWO4-Bi. It is proposed that blue-green and yellow luminescence occur by recombination correspondingly of free holes and free electrons at different intr…

Telestratora modulis profesionālajam sportam

2016

“Telestrātora modulis profesionālajam sportam” izstrādāts “SIA Playgineering Systems” uzņēmuma vajadzībām, tas lietotnes gala versijā ļaus lietotājam izveidot un atskaņot specifiska veida prezentācijas profesionālajam sportam . Lai izveidotu video “prezentāciju” lietotājam būs iespējams atvērt populārāko formātu video failu, un pauzes laikā ar piedāvātajiem rīkiem veidot informatīvu zīmējumu, kā arī pēc prezentācijas izveides saglabāt projektu, lai to varētu atskaņot un prezentēt vēlāk. Lietotne tika veidota programmēšanas valodā Python, projekti tika saglabāti ar JSON datu struktūras palīdzību, video kontrolēšana un atskaņošana tika realizēta ar Gstreamer palīdzību, kā arī dizains veidots …

An electrochemical quartz crystal microbalance study of lithium insertion into thin films of tungsten trioxide II. Experimental results and compariso…

1995

Abstract Lithium insertion into amorphous thin films of tungsten trioxide (a-WO 3 ) prepared by thermal vacuum evaporation of WO 3 powder has been studied experimentally by chronoamperometry, cyclic voltammetry and ac impedance spectroscopy associated with electrochemical quartz crystal microbalance (EQCM). During cathodic polarization of the electrode and at short times two antagonistic processes occur. One is a non faradaic process and is associated with the expulsion of anions from the electrode surface under the effect of the electric field built in the electrolyte when a potential difference is imposed between the electrodes. The other one is the faradaic insertion of non-solvated lith…

An electrochemical quartz crystal microbalance study of lithium insertion into thin films of tungsten trioxide I. Modeling of the ionic insertion mec…

1995

A theoretical description of the mechanism of lithium insertion into amorphous thin films of tungsten trioxide (a-WO3) prepared by thermal vacuum evaporation of WO3 powder is presented. The model developed is based on the experimental results obtained by chronoamperometry and ac impedance spectroscopy associated with electrochemical quartz crystal microbalance (EQCM). The electrode mass change and the current flowing through the electrochemical cell during cathodic polarization are simulta neously recorded. As expected, it can be observed that the insertion process is associated with a gain of mass of the inserted electrode at long times (t > 1 s). On the other hand at short times (t < 1 s)…

STOP 5: Veselava end moraine, north-western Vidzeme Upland

2014

Hepatic and branchial xenobiotic biomarker responses in Solea spp. from several NW Mediterranean fishing grounds

2015

9 pages, 4 figures, 4 tables

Validation of a very simple model for computing global solar radiation in the European, African, Asian and North American areas

1990

Abstract In a previous paper Coppolino has proposed a very simple model for predicting the monthly mean daily global solar radiation G (MJm −2 day −1 ) at any Italian location using as input only the sunshine duration s (hours) and the noon altitude of the sun on the 15th of the month h n (degrees). The correlation suggested is G = 7.8 s 0.5 (sin h n ) 1.15 . Herein the validity of this model is verified by extending its application to dat from 24 stations displaced at various latitudes, altitudes above sea level and geographical situations in the European, African, Asian and North American areas. Furthermore the validity of this model to fit the data of the tested stations is compared with…

WOx phase growth on SiO2/Si by decomposition of tungsten hexacarbonyl:Influence of potassium on supported tungsten oxide phases

2009

International audience; Synchrotron based photoemission spectroscopy was used to study the adsorption of tungsten hexacarbonyl on SiO2 surfaces modified by potassium. Results were compared with the ones obtained when no potassium was present. Experiments using W4f and Si2p intensities variations show that, at 140 K, the tungsten hexacarbonyl growth proceeds via a simultaneous multilayer mode for the two kinds of surfaces but with differences in compositions of growing layers. Indeed, it is evidenced that, even at cryogenic temperatures, the presence of potassium induces decomposition of a significant part of tungsten hexacarbonyl molecules through a strong interaction between tungsten and p…

Divdimensionālās šķidruma hromatogrāfijas augstas izšķirtspējas masspektrometrijas metodes izstrāde mikotoksīnu noteikšanai Puer tējās

2019

Maģistra darba ietvaros tika izstrādāta inovatīva divdimensionālās šķidruma hromatogrāfijas metode tandēmā ar augstas izšķirtspējas nolidojuma laika masspektrometriju (2D-LC-TOF-HRMS) 70 “jauno” un reglamentēto mikotoksīnu noteikšanai Puer tēju matricā. Šis uzdevums tika izvirzīts ar mērķi palielināt nosakāmo mikotoksīnu skaitu, uzlabot metodes selektivitāti un novērst traucējošo matricas komponentu efektu, pielietojot savienojumu atdalīšanu ar 2D-LC sistēmas palīdzību. Metode tika validēta saskaņā ar Eiropas Savienības analīzes metodes vadlīnijām. Izstrādātā online-heart-cutting-2D-HPLC-HRMS metode tika pielietota 20 Latvijā komerciāli pieejamajiem Puer tēju paraugiem, veicot analizēto mik…

Metodes izstrāde per- un polifluoralkil savienojumu noteikšanai pārtikas produktos, izmantojot augstas izšķirtspējas masspektrometriju

2022

Metodes izstrāde per- un polifluoralkil savienojumu noteikšanai pārtikas produktos, izmantojot augstas izšķirtspējas masspektrometriju. Jevņeviča K., zinātniskā vadītāja Mg.chem. Pasečnaja E. Bakalaura darbs, 41 lappuse, 5 attēli, 9 tabulas, 53 literatūras avoti. Latviešu valodā. Bakalaura darba ietvaros ir apkopota informācija par per- un polifluoralkil savienojumiem, to īpašībām, iedarbību uz cilvēkiem un apkārtējo vidi, toksicitāti, izplatību pārtikas produktos, kā arī ir apskatītas šo savienojumu noteikšanas metodes. Eksperimentālajā daļā ir izstrādāta un validēta analītiskā metode per- un polifluoralkil savienojumu noteikšanai pārtikas produktos, izmantojot augstas izšķirtspējas masspe…