Search results for "Emt"
showing 10 items of 413 documents
Photocycle of point defects in highly- and weakly-germanium doped silica revealed by transient absorption measurements with femtosecond tunable pump.
2022
AbstractWe report pump-probe transient absorption measurements addressing the photocycle of the Germanium lone pair center (GLPC) point defect with an unprecedented time resolution. The GLPC is a model point defect with a simple and well-understood electronic structure, highly relevant for several applications. Therefore, a full explanation of its photocycle is fundamental to understand the relaxation mechanisms of such molecular-like systems in solid state. The experiment, carried out exciting the sample resonantly with the ultraviolet (UV) GLPC absorption band peaked at 5.1 eV, gave us the possibility to follow the defect excitation-relaxation dynamics from the femto-picosecond to the nan…
Naratīvi un slepenu organizāciju reprezentācija Stenlija Kubrika spēlfilmā "Acis Plaši Aizvērtas"
2017
Bakalaura darba ietvaros tiek analizēta Stenlija Kubrika pilnmetrāžas spēlfilma “Acis Plaši Aizvērtas” (Eyes Wide Shut), kurā, līdztekus sižetam par seksuālu tematu vai tā aizsegā, ir atainota kādas slepenas organizācijas darbība. Darba teorētiskajā daļā ir apkopotas kinomākslas un komunikācijas pētnieku atziņas par kinematogrāfu kā komunikācijas platformu, atsevišķi aplūkojot tieši kino naratīvu un vizuālo komunikāciju, kā arī aplūkota un raksturota slepenu organizāciju darbība pasaulē, šodien un vēsturiski. Darba metodoloģiskajā daļā ir aplūkotas iespējamās analīzes metodes un pamatota naratīva un semiotiskās analīzes izvēle. Darba empīriskajā daļā ir identificēti un analizēti filmā atrod…
Temperature measurement in gas mixtures by femtosecond Raman-induced polarization spectroscopy
2003
European Conference on Nonlinear Optical Spectroscopy (ECONOS) MAR 30-APR 01, 2003 BESANCON, FRANCE; The potential of femtosecond Raman-induced polarization spectroscopy (RIPS) for the simultaneous determination of temperature and concentrations was investigated. These measurements were related to the rotational time response of the molecular gas mixture, which was measured as a function of the pump-probe time delay. The change of the polarizability anisotropy with respect to the vibrational levels was taken into account. The results of temperature measurements in pure CO2 showed good agreement with the values obtained by a thermocouple. The RIPS technique was also applied to a CO2-N2 gas m…
Photodynamics studies of ligand-protected gold nanoclusters by using ultrafast transient infrared spectroscopy
2015
Highly monodisperse samples of three ligand-protected gold nanoclusters Au102(pMBA)44, Au144(SC2H4Ph)60, and a cluster tentatively identified as Au130(pMBA)50, were characterized by UV/vis and infrared spectroscopy, and their photodynamics was studied by transient absorption spectroscopy. The dynamics study for each cluster was performed by electronically exciting the cluster with a pump pulse in the visible or near infrared region and by monitoring the transient absorption of vibrational modes of the ligands with a mid-IR probe pulse. The photodynamics studies were used to determine the molecular or metallic behavior of the cluster, and also to gain important size dependent information abo…
Karsējkomandas dejotāju uztura izvērtējums treniņu un uzstāšanās periodā
2018
Dejošana ir sporta veids, kur svarīgi ir sekot līdzi nepieciešamo uzturvielu uzņemšanai un uzņemtajai un patērētajai enerģijai, lai nepieļautu gan uzturvielu, gan enerģijas deficītu. Nepietiekams uzturs var ietekmēt dejotāju veselību un pazemināt rezultātus fiziskā slodzē gan treniņu, gan priekšnesuma laikā. Pētījuma mērķis ir izvērtēt karsējkomandas dejotāju uztura sastāva un ēšanas paradumu atbilstību sporta veida treniņu un uzstāšanās periodam. Pētījumā gaitā tika veikti dalībnieku antropometrisko parametru mērījumi, noteikts diennakts enerģijas patēriņš, izvērtēts ikdienas režīms un uztura paradumi un analizētas 7 dienu uztura dienasgrāmatas. Kā pētījuma metodes tika izmantotas aptaujas…
TP53 mutations and S-phase fraction but not DNA-ploidy are independent prognostic indicators in laryngeal squamous cell carcinoma
2005
To prospectively evaluate the prognostic significance of TP53, H-, K-, and N-Ras mutations, DNA-ploidy and S-phase fraction (SPF) in patients affected by locally advanced laryngeal squamous cell carcinoma (LSCC). Eight-one patients (median follow-up was 71 months) who underwent resective surgery for primary operable locally advanced LSCC were analyzed. Tumor DNA was screened for mutational analysis by PCR/SSCP and sequencing. DNA-ploidy and SPF were performed by flow cytometric analyses. Thirty-six patients (44%) had, at least, a mutation in the TP53 gene. Of them, 22% (8/36) had double mutations and 3% (1/36) had triple mutations. In total, 46 TP53 mutations were observed. The majority (41…
Impulsive excitation of high vibrational states in I2–Xe complex on the electronic ground state
2010
Abstract High vibrational states, up to ν = 22, are excited and investigated on the ground electronic state of a 1:1 I 2 –Xe complex isolated in solid Kr using femtosecond CARS technique and spontaneous resonant Raman measurements. The results show that this system is a promising candidate for investigations of coherent control of bimolecular reactions by using vibrational wavepackets on the ground electronic state.
Molecule-like photodynamics of Au102(pMBA)44 nanocluster.
2015
Photophysical properties of a water-soluble cluster Au102(pMBA)44 (pMBA = para-mercaptobenzoic acid) are studied by ultrafast time-resolved mid-IR spectroscopy and density functional theory calculations in order to distinguish between molecular and metallic behavior. In the mid-IR transient absorption studies, visible or near-infrared light is used to electronically excite the sample, and the subsequent relaxation is monitored by studying the transient absorption of a vibrational mode in the ligands. Based on these studies, a complete picture of energy relaxation dynamics is obtained: (1) 0.5-1.5 ps electronic relaxation, (2) 6.8 ps vibrational cooling, (3) intersystem crossing from the low…
Characterization of a novel three-dimensional outgrowth model of human bronchial mucosa
2011
Recently it has been hypothesized that a reactivation of the epithelial-mesenchymal trophic unit (EMTU) of the respiratory mucosa, caused by extensive epithelial damage, may be responsible for the pathogenesis of asthma. However, most research on this subject so far has been limited by the unavailability of in vitro models correctly mimicking the three-dimensional architecture of the properly differentiated human bronchial mucosa. For this reason, we have developed a novel 3D outgrowth model, obtained from bronchial biopsies and composed of both human bronchial epithelial cells (goblet and columnar cells) and fibroblasts with their basement membrane. Here we present the preliminary data obt…
Impact of Gamma Radiation on Dynamic R
2019
GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (RON_dyn) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (RDSON) char…