63 research outputs found
Thermal Conductivity of Isotopically Enriched 28Si Revisited
The thermal conductivity of isotopically enriched 28Si (enrichment better
than 99.9%) was redetermined independently in three laboratories by high
precision experiments on a total of 4 samples of different shape and degree of
isotope enrichment in the range from 5 to 300 K with particular emphasis on the
range near room temperature. The results obtained in the different laboratories
are in good agreement with each other. They indicate that at room temperature
the thermal conductivity of isotopically enriched 28Si exceeds the thermal
conductivity of Si with a natural, unmodified isotope mixture by 102 %.
This finding is in disagreement with an earlier report by Ruf et al. At
26 K the thermal conductivity of 28Si reaches a maximum. The maximum
value depends on sample shape and the degree of isotope enrichment and exceeds
the thermal conductivity of natural Si by a factor of 8 for a 99.982%
28Si enriched sample. The thermal conductivity of Si with natural isotope
composition is consistently found to be 3% lower than the values
recommended in the literature
Globus-M2 spherical tokamak and its mission in developing of compact fusion neutron source
Measurement of \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-) and \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)
The products of the electron width of the J/\psi meson and the branching
fraction of its decays to the lepton pairs were measured using data from the
KEDR experiment at the VEPP-4M electron-positron collider. The results are
\Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV,
\Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV.
Their combinations
\Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100)
keV,
\Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve
theaccuracy of the leptonic and full widths and test leptonic universality.
Assuming e\mu universality and using the world average value of the lepton
branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV
and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.Comment: 7 pages, 6 figure
Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector
We report results of a search for narrow resonances in e+ e- annihilation at
center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR
detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width
of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained
(at 90 % C.L.)
Measurement of main parameters of the \psi(2S) resonance
A high-precision determination of the main parameters of the \psi(2S)
resonance has been performed with the KEDR detector at the VEPP-4M e^{+}e^{-}
collider in three scans of the \psi(2S) -- \psi(3770) energy range. Fitting the
energy dependence of the multihadron cross section in the vicinity of the
\psi(2S) we obtained the mass value
M = 3686.114 +- 0.007 +- 0.011 ^{+0.002}_{-0.012} MeV and the product of the
electron partial width by the branching fraction into hadrons \Gamma_{ee}*B_{h}
= 2.233 +- 0.015 +- 0.037 +- 0.020 keV.
The third error quoted is an estimate of the model dependence of the result
due to assumptions on the interference effects in the cross section of the
single-photon e^{+}e^{-} annihilation to hadrons explicitly considered in this
work.
Implicitly, the same assumptions were employed to obtain the charmonium
leptonic width and the absolute branching fractions in many experiments.
Using the result presented and the world average values of the electron and
hadron branching fractions, one obtains the electron partial width and the
total width of the \psi(2S):
\Gamma_{ee} =2.282 +- 0.015 +- 0.038 +- 0.021 keV,
\Gamma = 296 +- 2 +- 8 +- 3 keV.
These results are consistent with and more than two times more precise than
any of the previous experiments
Passive Q-switching and mode-locking for the generation of nanosecond to femtosecond pulses
Zinc(II) Complex with 1,2-Bis(2-Pyridyl-1,2,4-Triazol-3-yl)ethane and Dianions of 1-Hydroxyethane-1,1-Diphosphonic Acid
ACETAZOLAMIDE IN PEDIATRIC NEUROLOGY: HISTORY AND PERSPECTIVE OF CILNICAL USE
Resume the up tob date pharmacological and clinical findings have revealed new opportunities for the use of known for a long time pharmaceutical agents in various fields of practical medicine. For more than 50 years acetozolamide, systemic carbonic anhydrase inhibitor, has been used in neurology to correct liquorodynamic disorders. High clinical efficacy and good tolerb ability in longbterm use has made acetazolamide an essential agent in pediatric neurology, along with this the true therapeutic application of acetazolamide is much wider than it was traditionally thought. This review analyzes the experience of administration of the drug in different branches of pediatric neurology, including those where acetazolamide has been traditionally used along with novel applications to administration of the drug in children.Key words: acetozolamide, carboanhydrase, children, sleep apnea syndrome, glaucoma, hydrocephaly, episodic ataxia type II, migraine, intracranial idiopathic benign hemiplegic hypertension
Spacer-Armed Copper(II) Complex Based on Bis(2-pyidyl-1,2,4-triazol-3-yl)butane and 1-Aminoethane-1,1-Diphosphonic Acid
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