A statistical mechanics framework for multi-particle production in high energy reactions

We deduce the particle distributions in particle collisions with multihadron-production in the framework of mechanical statistics. They are derived as functions of x, P_T^2 and the rest mass of different species for a fixed total number of all produced particles, inelasticity and total transverse energy. For P_T larger than the mass of each particle we get the behaviour \frac{dn_i}{dP_T} \sim \sqrt{P_T} e^{-\frac{P_T}{T_H}} Values of _\pi, _K, and _{\bar{p}} in agreement with experiment are found by taking T_H=180MeV (the Hagedorn temperature).Comment: 9 pages, RevTe

Inversionless light amplification and optical switching controlled by state-dependent alignment of molecules

We propose a method to achieve amplification without population inversion by anisotropic molecules whose orientation by an external electric field is state-dependent. It is based on decoupling of the lower-state molecules from the resonant light while the excited ones remain emitting. The suitable class of molecules is discussed, the equation for the gain factor is derived, and the magnitude of the inversionless amplification is estimated for the typical experimental conditions. Such switching of the sample from absorbing to amplifying via transparent state is shown to be possible both with the aid of dc and ac control electric fields.Comment: AMS-LaTeX v1.2, 4 pages with 4 figure

Auf dem Weg zu flugbrandresistenten Gerstensorten für den Ökolandbau

This paper represents a part of the continuing breeding program for resistance to true loose smut in barley in Bulgaria. It is also a continuation of the paper presented on the 8th European Symposium on organic farming in Kassel 2005. Research on seed-borne diseases started in Bulgaria on barley in the 1960´s at the Institute for barley Re-search in Karnobat. Breeding research especially for a later use in organic farming in Bulgaria started 1998 with the present international project managed by Dr. Todorova. 56 dihaploid lines were derived from F1-hybrids of two barley crosses between resis-tant and susceptible Bulgarian and foreign cultivars bearing the resistant genes Run12 and Run13. The DH progenies were tested in 5 generations for loose smut resistance on the field and in the lab with the embryotest. 10 resistant DH-progenies with gene Run12 and 16 resistant DH-progenies with Run13 were selected. In the last years agronomically characterisation of the future cultivars is going on. 7 dihaploid lines with appropriate agronomic traits are selected for future cultivar developing with true loose smut resistance for organic farming

On the problem of a thin rigid inclusion embedded in a Maxwell material

We consider a plane viscoelastic body, composed of Maxwell material, with a crack and a thin rigid inclusion. The statement of the problem includes boundary conditions in the form of inequalities, together with an integral condition describing the equilibrium conditions of the inclusion. An equivalent variational statement is provided and used to prove the uniqueness of the problem’s solution. The analysis is carried out in respect of perfect and non-perfect bonding of the rigid inclusion. Additional smoothness properties of the solutions, namely the existence of the time derivative, are also established

Thermal decomposition of a honeycomb-network sheet - A Molecular Dynamics simulation study

The thermal degradation of a graphene-like two-dimensional triangular membrane with bonds undergoing temperature-induced scission is studied by means of Molecular Dynamics simulation using Langevin thermostat. We demonstrate that the probability distribution of breaking bonds is highly peaked at the rim of the membrane sheet at lower temperature whereas at higher temperature bonds break at random anywhere in the hexagonal flake. The mean breakage time $\tau$ is found to decrease with the total number of network nodes $N$ by a power law $\tau \propto N^{-0.5}$ and reveals an Arrhenian dependence on temperature $T$. Scission times are themselves exponentially distributed. The fragmentation kinetics of the average number of clusters can be described by first-order chemical reactions between network nodes $n_i$ of different coordination. The distribution of fragments sizes evolves with time elapsed from a $\delta$-function through a bimodal one into a single-peaked again at late times. Our simulation results are complemented by a set of $1^{st}$-order kinetic differential equations for $n_i$ which can be solved exactly and compared to data derived from the computer experiment, providing deeper insight into the thermolysis mechanism.Comment: 21pages, 9 figures, LaTeX, revised versio