Search results for "Acs"
showing 10 items of 259 documents
Statics and dynamics of weakly coupled antiferromagnetic spin-1/2 ladders in a magnetic field
2011
We investigate weakly coupled spin-1/2 ladders in a magnetic field. The work is motivated by recent experiments on the compound (C5H12N)2CuBr4 (BPCB). We use a combination of numerical and analytical methods, in particular the density matrix renormalization group (DMRG) technique, to explore the phase diagram and the excitation spectra of such a system. We give detailed results on the temperature dependence of the magnetization and the specific heat, and the magnetic field dependence of the nuclear magnetic resonance (NMR) relaxation rate of single ladders. For coupled ladders, treating the weak interladder coupling within a mean-field or quantum Monte Carlo approach, we compute the transit…
An empirical model for free surface energy of strained solids at different temperature regimes.
2006
Abstract We have developed an empirical formulation, based on the elastic theory, to calculate the variation of the surface free energy when a crystal is strained in the elastic regime. The model permits to obtain the variation of the surface energy at different strains and temperatures when are known the thermal dependence on the bulk and surface elastic constants. Molecular dynamics (MD) simulations were performed using the three low index surfaces of Al, to validate the accuracy of the model. The comparison between the empirical model and the MD simulations shows a good agreement for temperatures ranging between 0 and 900 K, and for deformation between −2% and 2%.
Ridge-enhanced optical transmission through a continuous metal film
2004
Optical transmission through a continuous (without holes) metal film with a periodic structure of metal or dielectric ridges on one or both interfaces was numerically studied. The dependencies of the transmission on the ridge width and height as well as the ridge arrangements on the opposite interfaces were investigated in weak- and strong-coupling regimes. The transmission enhancement was shown to depend on the relative position of the ridge gratings on the opposite interfaces of a film, confirming the role of resonant tunneling processes involving states of the surface polariton Bloch modes.
On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium [Beta] spectroscopy
2000
The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed T2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated.
Asaru osmolaritāte dažādu profesiju pārstāvjiem
2019
Bakalaura darbs ir uzrakstīts latviešu valodā datorsalikumā uz 34 lapaspusēm. Tas satur 19 attēlus, 4 tabulas, 33 atsauces uz literatūras avotiem. Darba mērķis bija novērtēt vides faktoru ietekmi uz asaru osmolaritāti, salīdzināt ar ārā strādājošo dalībnieku rezultātiem ar iekšā strādājošo dalībnieku rezultātiem. Pētījums tika veikts 2. posmos, 1. posms anketēšanas daļa kurā piedalījās 200 cilvēku, 2. posms kurā notika osmolaritātes mērījumi, piedalījās 105 cilvēki. Rezultāti pieradīja, kad gaisa relatīvais mitrums atstāj ietekmi uz asaru osmolaritāti un nav būtisku izmaiņu starp dalībnieku grupām.
Conductes de risc associades en jugadors patològics i professionals de pòquer i escacs
2016
espanolEl juego esta cada dia mas presente en la sociedad con prevalencias muy importantes, sobre todo, en jovenes y adolescentes. Como consecuencia, este estudio tiene como objetivo estudiar la relacion entre el juego patologico, el juego a nivel aficionado el juego profesional (ajedrez y poquer) en el control de impulsos y en el consumo de alcohol. Para ello, se ha utilizado una muestra compuesta por jugadores aficionados y profesionales de ajedrez y poquer, un grupo de jugadores patologicos y un grupo control. Los instrumentos han medido conducta de riesgo de ingesta de alcohol, control de impulsos y los criterios diagnosticos de juego patologico. Los principales resultados han mostrado …
Influence of geographical extent on typology- and model-based assessments of taxonomic completeness of river macroinvertebrates
2009
Summary 1. River InVertebrate Prediction and Classification System (RIVPACS)-type predictive models are increasingly used to assess the biological condition of freshwaters, but management schemes may also be based on a priori groupings of similar water bodies (typologies) to control for natural variation in biota. The two approaches may lead to disagreements of the biological status of a site, depending on, for example, the spatial scale at which assessments are conducted. 2. We used data from 96 reference and 134 potentially impacted sites from Western and Central Finland to compare RIVPACS-type models and a simple size-based typology of rivers for the assessment of taxonomic completeness …
Chiral Low-Energy Constants: Status and Prospects
2007
7 pages.-- PACS nrs.: 11.15.Pg, 12.38.-t, 12.39.Fe.-- ISI Article Identifier: 000252187200017.-- ArXiv pre-print available at: http://arxiv.org/abs/0710.4405
Vadošās acs stabilitāte un binokulārā konkurence
2017
Bakalaura darbs ir uzrakstīts latviešu valodā , tā apjoms 27 lapas. Darbs satur 27 attēlus, 3 tabulas un 28 atsauces uz literatūras avotiem. Pētījuma mērķis ir noskaidrot motorās vadošās acs un sensorās vadošās acs ietekmi uz dominances ilgumu binokulārās konkurences laikā. Noskaidrot, kā binokulārās konkurences attēlu maiņu ietekmē vadošā acs un tās stabilitāte. Novertēt vadošās acs un vadošās sensorās acs sakritību un to ietekmi uz dominances ilgumu binokulārās konkurences laikā, kā attēlu maiņu ietekmi binokulārās konkurences laikā.
LU FMOF optometrijas un redzes zinātnes nodaļas un Latvijas optometristu un optiķu asociācijas konferenču referātu tēzes
2012
Krājumā apkopotas Latvijas Universitātes 70. zinātniskās konferences (DABAS ZINĀTNES, FIZIKA, Redzes uztveres sekcija (2012. gada 10. februāris) un LU Optometrijas un redzes zinātnes nodaļas un LOOA kopīgās klīniski praktiskās konferences (2012. gada 12. februāris)) tēzes.