Relativistic Nucleus-Nucleus Collisions: Zone of Reactions and Space-Time Structure of a Fireball

A zone of reactions is determined and then exploited as a tool in studying the space-time structure of an interacting system formed in a collision of relativistic nuclei. The time dependence of the reaction rates integrated over spatial coordinates is also considered. Evaluations are made with the help of the microscopic transport model UrQMD. The relation of the boundaries of different zones of reactions and the hypersurfaces of sharp chemical and kinetic freeze-outs is discussed.Comment: 6 pages, 5 figure

One-photon scattering by an atomic chain in a two-mode resonator: cyclic conditions

In this work, a chain of N identical two-level atoms coupled with a quantized electromagnetic field, initially prepared via a single-photon Fock state, is investigated. The N-particle state amplitude of the system is calculated for several space configurations of the atoms in the Weisskopf-Wigner approximation. It was shown that the space configuration of an atomic chain, the total number of atoms, and even the available volume for the field modes define the behavior of the system state amplitude with time. Applying the condition of ‘cyclic bonds’, presented in this work, to the elaborated theory allows to describe the system time evolution, practically, for any space configuration

Collision Thermalization of Nucleons in Relativistic Heavy-Ion Collisions

We consider a possible mechanism of thermalization of nucleons in relativistic heavy-ion collisions. Our model belongs, to a certain degree, to the transport ones; we investigate the evolution of the system created in nucleus-nucleus collision, but we parametrize this development by the number of collisions of every particle during evolution rather than by the time variable. We based on the assumption that the nucleon momentum transfer after several nucleon-nucleon (-hadron) elastic and inelastic collisions becomes a random quantity driven by a proper distribution. This randomization results in a smearing of the nucleon momenta about their initial values and, as a consequence, in their partial isotropization and thermalization. The trial evaluation is made in the framework of a toy model. We show that the proposed scheme can be used for extraction of the physical information from experimental data on nucleon rapidity distribution.Comment: 13 pages, 8 figure

Full and Partial Thermalization of Nucleons in Relativistic Nucleus-Nucleus Collisions

We propose a mechanism of thermalization of nucleons in relativistic nucleus-nucleus collisions. Our model belongs, to a certain degree, to the transport ones; we consider the evolution of the system, but we parametrize this development by the number of collisions of every particle in the system rather than by the time variable. We based on the assumption that the nucleon momentum transfer after several nucleon-nucleon (-hadron) collisions becomes a random quantity driven by a proper distribution.Comment: 5 pages, 2 figures, Talk given at the Conference on Strong and Electroweak Matter (SEWM08), August 26-29, 2008, Amsterdam, the Netherland

The effect of desynchronizing effects of transmeridian flights on the chronoresistance of athletes

Objective: to study the effect of transmeridian air movements in contrasting geosocial conditions of competition on the direction and duration of stabilization of the chrono-resistance of athletes during periods of desynchronosis. Materials and methods: the study involved 103 highly skilled athletes – men of various specialties (age 22.6 ± 4.2 years). On the model of air movements across 7 time zones, the frequency, structure, and focus of reducing or increasing medical circulation reflecting the body's resistance during chronoadaptation were analyzed. Results: before the flight, athletes' visits to the doctor were rare exceptions. After air travel, pathological manifestations in health status were detected in more than 40% of migrants. Over 50% of the medical treatment accounted for well-compensated foci of chronic infection, relapses of erased diseases and injuries. The maximum frequency of medical treatment was observed at the 2-3rd week after the flight, at the 5th week - sporadic, but higher than in the "home" conditions. Conclusions: for the relative stabilization of the body's resistance in athletes in contrasting geo-modern regions, more than a month of acclimatization is required. The minimal decrease in the chrono-resistance direction is manifested at 2-3 weeks after the flight in the stage of transition of «acute» desynchronosis to hidden

Speed Dependences of Mechanical Properties in 316L Steel Samples, Manufactured by 3D-Laser Printing

Влияние скорости деформации на механические свойства пористых образцов из стали 316L, полученных лазерной 3D-печатью, было исследовано при комнатной температуре с помощью испытаний на растяжение и фрактографию. Обнаружено аномальное увеличение относительного удлинения и предела прочности при увеличении скорости растяжения. В зоне разрушения наблюдали двойники деформации.The effect of strain rate on mechanical properties of 3D laser printed porous 316L steel samples was investigated by tensile test and scanning electron microscope fractography. The anomalous increase of elongation and ultimate stress with the tensile deformation rate was found. Deformation twins were observed in the destruction zone.Работа выполнена в рамках государственного задания (тема «Диагностика», № АААА–А18–118020690196–3).The work was carried out within the framework of the state task (the topic “Diagnostics”, № AAAAA–A18–118020690196–3)

Просторово-часова структура релятивістських ядро-ядерних зіткнень

With making use of the proposed algorithm for determination of the reaction zone the space-time structure of relativistic nucleus-nucleus collisions is investigated. The reaction zones and reaction frequencies for different type of reactions are calculated for AGS and SPS energies within the microscopic transport model UrQMD. The reaction zone boundary hyper surfaces, which can be associated with freeze out process, are found. On the basis of performed calculations the characteristic points of the time dependence of fireball evolution are obtained.При помощи предложенного алгоритма для определения зоны реакций исследовано пространственно-временную структуру релятивистских ядро-ядерных столкновений. Используя микроскопическую транспортную модель UrQMD, построены зоны адронных реакций и частоты реакций разного типа для условий экспериментов AGS и SPS. Получено гиперповерхности, которые могут быть асоциированы с процесом фризаута. На основе проведенных расчетов выявлены характерные точки во временной эволюции фаербола.За допомогою запропонованого алгоритму для визначення зони реакцій досліджено просторово-часову структуру релятивістських ядро-ядерних зіткнень. Використовуючи мікроскопічну транспортну модель UrQMD, побудовано зони адронних реакцій та частоти реакцій різного типу для умов експериментів AGS і SPS. Отримано гіперповерхні, які можуть бути асоційовані з процесом фрізауту. На основі проведених розрахунків виявлено характерні точки у часовій еволюції фаєрбол