30 research outputs found
On the Analysis of Chemical Composition of Moon's Surface by Direct Methods
Proportional counter for X ray emission detection and chemical analysis of lunar surface element
Experimental data as evidence against the hypothesis on the earth's dust cloud
Cosmos and Explorer satellite data used to reject hypothesis of terrestrial meteoroid and dust cloud
Channeling Effect and Improvement of the Efficiency of Charged Particle Registration with Crystal Scintillators
The importance is emphasized of taking into account the channeling along the
low index crystallographic axes and planes of a part of low-energy (1-10 keV)
recoil ions in measurements of their parameters with crystal scintillators of
the type of NaI(Tl) etc. Because the nucleus stopping power in channels is low
as compared with electronic stopping power, the light yield of the scintillator
must be, accordingly, higher in the given case than that for ions having higher
energy (tens keV and more), which lose most part of their energy via nuclear
collisions outside channels. Hence, in particular, it follows that the DAMA/NaI
observations in Gran Sasso of the annual modulation of the signal frequency in
a narrow range of scintillations with an amplitude of 2-6 keV electron
equivalent may be due to incidence onto the Earth of exceedingly massive
particles (of the type of Planckian objects) from elongated Earth-crossing
heliocentric orbits at a velocity of 30-50 km/s. In NaI(Tl), these particles
create the iodine recoil ions with just the energy of 2-6 keV.Comment: 10 page
Methacrylate compositions modified by oligosilsesquioxanes with methacryl and cyclotriphosphazene substituents
Triethoxysilylphosphazenes have been synthesized via hydrosilylation of cyclotriphosphazenes with various contents of 4-allyl-2-methoxyphenoxy groups by triethoxysilane at an equimolar phosphazene - silane ratio. Hydrolytic copolycondensation of the latter compounds with γ-methacryloxypropyltrimethoxy - silane resulted in oligosiloxanes involving functional methacrylic and phosphazene fragment
Absence of molecular mobility on nano-second time scales in amorphous ice phases
High-resolution neutron backscattering techniques are exploited to study the
elastic and quasi-elastic response of the high-density amorphous (HDA), the
low-density amorphous (LDA) and the crystalline ice Ic upon temperature
changes. Within the temperature ranges of their structural stability (HDA at T
> 80 K, LDA at T > 135 K, ice Ic at T < 200 K) the Debye-Waller factors and
mean-square displacements characterise all states as harmonic solids. During
the transformations HDA->LDA (T ~ 100 K), LDA->Ic (T ~ 150K) and the supposed
glass transition with Tg ~ 135 K no relaxation processes can be detected on a
time scale t < 4 ns. It can be concluded from coherent scattering measurements
(D_2O) that LDA starts to recrystallise into ice Ic at T ~ 135 K, i.e. at the
supposed Tg. In the framework of the Debye model of harmonic solids HDA reveals
the highest Debye temperature among the studied ice phases, which is in full
agreement with the lowest Debye level in the generalised density of states
derived from time-of-flight neutron scattering experiments. The elastic results
at low T indicate the presence of an excess of modes in HDA, which do not obey
the Bose statistics
Neutron Scattering Study of the Localized Mode in the beta-Pyrochlore Superconductors AOs2O6
Inelastic neutron scattering and neutron powder diffraction experiments were
carried out to investigate a localized mode, proposed from various bulk
measurements, in the beta-pyrochlore AOs2O6 (A=K, Rb, Cs). The localized mode
was identified in all the three compounds as well as another beta-pyrochlore
CsW2O6. The anharmonicity of the mode is weak in RbOs2O6 and CsOs2O6 but
substantial in KOs2O6.Comment: 12 pages, 6 figures; typos and graph correcte
Possible implications of the channeling effect in NaI(Tl) crystals
The channeling effect of low energy ions along the crystallographic axes and
planes of NaI(Tl) crystals is discussed in the framework of corollary
investigations on WIMP Dark Matter candidates. In fact, the modeling of this
existing effect implies a more complex evaluation of the luminosity yield for
low energy recoiling Na and I ions. In the present paper related
phenomenological arguments are developed and possible implications are
discussed at some extent.Comment: 16 pages, 10 figures, preprint ROM2F/2007/15, submitted for
publicatio
Methacrylate compositions modified by oligosilsesquioxanes with methacryl and cyclotriphosphazene substituents
Triethoxysilylphosphazenes have been synthesized via hydrosilylation of cyclotriphosphazenes with various contents of 4-allyl-2-methoxyphenoxy groups by triethoxysilane at an equimolar phosphazene - silane ratio. Hydrolytic copolycondensation of the latter compounds with γ-methacryloxypropyltrimethoxy - silane resulted in oligosiloxanes involving functional methacrylic and phosphazene fragment