Autor: Hirade, T. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Ortho-Positronium Annihilation in Room Temperature Ionic Liquids
Autorzy:: Hirade, T.
Powiązania:: https://bibliotekanauki.pl/articles/1030029.pdf
Data publikacji:: 2017-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
Opis:: Very new phenomena have been found in room temperature ionic liquids, e.g. oscillation of positronium (Ps) bubble. It is almost impossible to see this kind of phenomenon in usual molecular liquids. The Ps bubble oscillations in N,N,N-trimethyl-N-propylammonium bis(trifluoro-methanesulfonyl)imide (TMPA-TFSI), N-methyl-N-propylpiperidinium bis(trifluoromethane-sulfonyl) imide (PP13-TFSI) and 1-ethyl-3-methylimidazolium thiocyanate (EMIM-SCN) were successfully observed. Even though the Ps bubble size is smaller for EMIM-SCN, the oscillation frequency of the Ps bubble at 10°C above the melting temperatures was quite similar for the other room temperature ionic liquids. Hence, the Ps bubble oscillation is, probably, caused by the repulsive force initiated by the ionic structures in room temperature ionic liquids that can remain at 10-15°C above the melting temperatures.
Źródło:: Acta Physica Polonica A; 2017, 132, 5; 1470-1472
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Positronium Formation at Low Temperatures in Polymers and Other Molecular Solids
Autorzy:: Hirade, T.
Powiązania:: https://bibliotekanauki.pl/articles/2042181.pdf
Data publikacji:: 2005-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 36.10.Dr
78.70.Bj
36.20.Kr
Opis:: Positronium (Ps) formation by weakly localized long-lived electrons (trapped electrons or anions) and positrons at low temperatures successfully explained the Ps formation enhancement at low temperatures observed in polymers and molecular solids. This Ps formation process is different from Ore process and spur process. The phenomena expected by this Ps formation mechanism, such as an effect due to visible light exposure, a density dependence of weakly localized electrons and the delayed Ps formation were successfully observed as the experimental evidence of this Ps formation process. Some possibilities for application of this new Ps formation were also given. One is a new idea for estimation of spin polarity of positrons. Another is the possibility of application to study the local molecular motion by observing the decay of Ps formation intensity.
Źródło:: Acta Physica Polonica A; 2005, 107, 4; 615-622
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Positron Annihilation Methods by Use of LSO Scintillators
Autorzy:: Hirade, T.
Oka, T.
Powiązania:: https://bibliotekanauki.pl/articles/1339992.pdf
Data publikacji:: 2014-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
Opis:: $Lu_2SiO_5$:Ce (LSO) scintillator is one of the scintillators used for positron emission tomography because of its high efficiency of gamma-ray detection. We tried to use LSO for positron annihilation lifetime and age-momentum correlation measurements because the high efficiency is needed to reduce the positron irradiation effect during measurements. The high efficiency with reasonable time resolution was successfully obtained by use of the dynode signals from photomultiplier tubes.
Źródło:: Acta Physica Polonica A; 2014, 125, 3; 825-828
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: The Effect of Visible Light Irradiation on Positronium Formation in Polyethylene at Low Temperature
Autorzy:: Ito, Y.
Hirade, T.
Hamada, E.
Suzuki, T.
Powiązania:: https://bibliotekanauki.pl/articles/2007996.pdf
Data publikacji:: 1999-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
Opis:: The effect of visible light exposing on the ortho-positronium formation in polyethylene was studied. Lifetime spectra of positrons in polyethylene were measured in the temperature range between 50 K and 370 K. It was observed that the visible light quenches the enhancement of ortho-positronium intensity (I$\text{}_{3}$) at lower temperature than ca. 250 K - the glass transition temperature of polyethylene. On the other hand, the lifetime of ortho-positronium component (τ$\text{}_{3}$) was not affected by the presence of the visible light.
Źródło:: Acta Physica Polonica A; 1999, 95, 4; 533-538
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Role of Trapped and Solvated Electrons in Ps Formation
Autorzy:: Stepanov, S. V.
Byakov, V. M.
He, C.
Hirade, T.
Mikhin, K. V.
Powiązania:: https://bibliotekanauki.pl/articles/2042190.pdf
Data publikacji:: 2005-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.80.Fe
36.10.Dr
78.70.Bj
82.35.Lr
Opis:: Role of trapped and solvated electrons in Ps formation is discussed. Combination of thermalized positron with such electrons is possible from the viewpoint of the energy balance and may results in Ps formation. This process proceeds during all e$\text{}^{+}$ lifetime in matter. Fitting of raw experimental e$\text{}^{+}$ - e$\text{}^{-}$ annihilation spectra has to be based on an adequate physical input, which often leads to necessity of nonexponential deconvolution of the spectra. We have interpreted the Ps formation data in polyethylene, ethylene-methylmethacrylate and polymethylmethacrylate in dark and in light vs. time of the measurement and temperature. Parameters characterized accumulation of trapped electrons and their recombination with counter ions and positrons are obtained.
Źródło:: Acta Physica Polonica A; 2005, 107, 4; 642-650
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 6.

Tytuł:: Comments on the Effect ofγ-Irradiation on Positronium Formation in Polymers at Low Temperatures
Autorzy:: Shantarovich, V. P.
Hirade, T.
Kevdina, I. B.
Gustov, V. W.
Oleinik, E. F.
Powiązania:: https://bibliotekanauki.pl/articles/2025760.pdf
Data publikacji:: 2001
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
Opis:: Quantitative description of the effect of γ-irradiation of PE and PMMA on positronium formation on the trapped electrons at low temperatures is suggested. The consideration shows that, at least in these substances, the number of the trapping centers is probably enough to localize all ortho-positronium, and therefore the intensity of the long-lived positronium component is dependent mostly on the probability of Ps formation but not on the number of the trapping centers.
Źródło:: Acta Physica Polonica A; 2001, 99, 3-4; 497-501
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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