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Underwater experiments for an ideal explosive, TNT, and two nonideal explosives, CETR emulsion and DXD-04, were performed, and numerically simulated. For TNT, calculations done by using program-burn models based on the rate-independent Chapman-Jouguet theory were in a good agreement with experimental results, which validated the wide use of program-burn models for ideal explosives. For CETR emulsion and DXD-04, experimental observations could be reproduced with high precision only when reaction rates were employed. These results demonstrated that detonation in nonideal explosives can be modeled only by using properly calibrated reaction rates.

A development has been made for the charged-particle-induced nonresonant reaction-rate equations. The forms of reaction-rate equations for nonresonant and resonant reactions have been united in a frame of Lorentzian-Function Approximation (LFA) mathematically. In the frame of LFA, the nonresonant reaction taken place within the Gamow window can be considered, in form, as a "resonance" reaction with a full width at half maximum (FWHM, Γ^nr) equal to the 1/e width (Δ) in a well-known Gaussian-Function Approximation (GFA).

On the basis of the proposed algorithm for calculation of the hadron reaction rates, the space-time structure of the relativistic nucleus–nucleus collisions is studied. The reaction zones and the reaction frequencies for various types of reactions are calculated for Alternating Gradient Synchrotron (AGS) and Super Proton Synchrotron (SPS) energies within the microscopic transport model. The relation of the reaction zones to the kinetic and chemical freeze-out processes is discussed. It is shown that the space-time freeze-out layer is most extended in time in the central region, while, especially for higher collision energies, the layer becomes very narrow at the sides. The parametrization of freeze-out hypersurface in the form of specific hyperbola of constant proper time was confirmed. The specific characteristic time moments of the fireball evolution are introduced. It is found that the time of the division of a reaction zone into two separate parts does not depend on the collision energy. Calculations of the hadronic reaction frequency show that the evolution of nucleus–nucleus collision can be divided into two hadronic stages.

The reaction ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O was investigated through the direct $\alpha$-transfer reaction (⁷Li,t) at 28 and 34 MeV incident energies. We determined the reduced $\alpha$-widths of the sub-threshold 2${}^{+}$ and 1${}^{-}$ states of ${}^{16}$O from the DWBA analysis of the transfer reaction ${}^{12}$C(⁷Li,t)${}^{16}$O performed at two incident energies. The obtained result for the 2${}^{+}$ and 1${}^{-}$ sub-threshold resonances as introduced in the $R$-matrix fitting of radiative capture and elastic-scattering data to determine the E2 and E1 $S$-factor from 0.01MeV to 4.2MeV in the center-of-mass energy. After determining the astrophysic factor of ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O S(E) with Pierre Descouvement code, I determined numerically the new reaction rate of this reaction at a different stellar temperature (0.06 Gk-2 GK). The ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O reaction rate at T${}_9=0.2$ is [7.21${}_{-2.25}^{+2.15}$] × 10${}^{-15}$ cm³ s${}^{-1}$ mol${}^{-1}$. Some comparisons and discussions about our new ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O reaction rate are presented. The agreements of the reaction rate below T${}_9=2$ between our results and with those proposed by NACRE indicate that our results are reliable, and they could be included in the astrophysical reaction rate network.

In this study, microscopic nucleon–nucleon Double Folding (DF) and phenomenological potentials have been used to investigate $\alpha {+}^{40}$Ca reaction observables at sub-barrier energies. In the calculations, semi-classical Wentzel–Kramers–Brillouin (WKB) approach has been used in order to obtain the cross-sections and reaction rates of $\alpha {+}^{40}$Ca. Besides WKB approximation, we have also utilized Talys code in order to get the comparative results and find out the method differences. To estimate the reaction rates, energy-dependent cross-sections and astrophysical S-factors of $\alpha$+${}^{40}$Ca have been used. Herewith, differences between models and potentials have been demonstrated using the reaction rate estimates.

The reaction ${}^{13}$C${(\alpha ,n)}^{16}$O is an important astrophysical process producing neutrons for $s$-process nucleosynthesis of nuclei heavier than iron in low-mass AGB stars. The reaction rate of ${}^{13}$C${(\alpha ,n)}^{16}$O at relevant energies is dominated by a ${1/2}^{+}$ state in ${}^{17}$O near the $\alpha$-threshold. The adopted value for the excitation energy of the state is −3keV below the threshold at 6359keV. However, recent investigations have indicated that the state is, instead of a sub-threshold state, an above threshold resonance state. The observation is also corroborated by neutron scattering studies from ${}^{16}$O. The location of the state and its implication on the low energy behavior of the astrophysical $S$-factor are of definite interest. The aim of this work is to ascertain the energy location of ${1/2}^{+}$ state in the excitation spectrum of ${}^{17}$O and to estimate its neutron and $\alpha$-partial widths. Subsequently, we look into the effect of the resultant set of parameters of the state on the $S$-factor and reaction rate at important astrophysical energies. A multilevel, multichannel $R$-matrix analysis has been performed for the existing ${}^{16}$O$(n,n)$, ${}^{13}$C$(\alpha ,n)$, ${}^{13}$C$(\alpha ,\alpha )$ and ${}^{16}$O$(n,\alpha )$ data. The excitation energy of the $1/2+$ state in ${}^{17}$O is found to be at 6371.9keV, about 12.9keV above the threshold. The resulting $S$-factor around the Gamow energy of 190keV $(T_9\sim 0.1)$ is $(1.91\pm 0.27)\times 10^6$$\mathrm{\text{MeV}}\cdot \mathrm{\text{b}}$. Relatively, higher $S$-factor value yields a larger reaction rate for ${}^{13}$C($\alpha ,n$)${}^{16}$O at the required temperature window. Consequently, larger number of neutrons relevant to $S$-process nucleosynthesis will be produced from ${}^{13}$C${(\alpha ,n)}^{16}$O reaction.

The original version of the activation method is presented and yield of the astrophysical relevant reaction ${}^{12}C{(p,\gamma )}^{13}N$ has been measured at the energy region 190–650keV using this method. The rate of this reaction was calculated within the temperature region $0.01\le T_9\le 1.0$ through the yield values. The possibility of improving the method for measuring very small yields or cross sections was demonstrated.

The stability of an organic compound depends on its nature and the environment in which it is placed. It depends on the presence or absence of reagents (acid, base, oxidizing agent, reducing agent, light, etc.) and catalysts. The stability may not be the same in the solid, liquid or gaseous state. In a homogenous solution, the stability might be affected by the polarity of the solvent and its concentration. For instance a polar solvent favors ionization. In a non-polar solvent ionization is difficult. In the gas phase ionization never occurs. In the gas phase and in solution stability depends on pressure and the presence of impurities. We are interested here in the thermal stability of pure compounds in the gas phase or in non-polar solvents under one atmosphere…