191 research outputs found
Heat capacity and phonon mean free path of wurtzite GaN
We report on lattice specific heat of bulk hexagonal GaN measured by the heat
flow method in the temperature range 20-300 K and by the adiabatic method in
the range 5-70 K. We fit the experimental data using two temperatures model.
The best fit with the accuracy of 3 % was obtained for the temperature
independent Debye's temperature {\rm K} and Einstein's
temperature {\rm K}. We relate these temperatures to the
function of density of states. Using our results for heat conduction
coefficient, we established in temperature range 10-100 K the explicit
dependence of the phonon mean free path on temperature . Above 100 K, there is the evidence of contribution of the Umklapp
processes which limit phonon free path at high temepratures. For phonons with
energy {\rm K} the mean free path is of the order 100
{\rm nm}Comment: 5 pages, 4 figure
The Lake Baikal neutrino experiment: selected results
We review the present status of the lake Baikal Neutrino Experiment and
present selected physical results gained with the consequetive stages of the
stepwise increasing detector: from NT-36 to NT-96. Results cover atmospheric
muons, neutrino events, very high energy neutrinos, search for neutrino events
from WIMP annihilation, search for magnetic monopoles and environmental
studies. We also describe an air Cherenkov array developed for the study of
angular resolution of NT-200.Comment: 25 pages, 12 figures. To appear in the Procrrdings of International
Conference on Non-Accelerator New Physics, June 28 - July 3, 1999, Dubna,
Russi
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