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Radiation hazard on board of a relativistic rocket can be of internal and external origin. Because of its highest specific energy density, antimatter is considered to be the preferred rocket fuel for accelerating a multi-ton rocket up to relativistic speed. High-energy products of matter-antimatter annihilation (gamma-photons and meson radiation) can produce a severe radiation hazard for crew and electronics. Another factor that can stand against our pursuit to the stars is intense nucleons radiation produced by the oncoming relativistic headwind of interstellar gas and cosmic rays with their intensity increasing with rocket velocity. When a rocket accelerates to a relativistic speed, the rarefied interstellar gas of neutral and ionized atoms and molecules transforms into the oncoming flux of high-energy nucleons irradiating the rocket body and creating the severe radiation hazard. The oncoming flux of relativistic dust granules imposes a threat of mechanical damage to the rocket body., Comment: 27 pages, 10 figures

Two technological problems must be solved before daring to interstellar flight: fuel and propulsion. The highest energy-density fuel is antimatter in its solid or liquid state and this fuel is likely to be our primary choice for multi-ton relativistic rockets. High-energy ion thruster powered by annihilation reactor promises superior performance in comparison with direct propulsion by annihilation products. However the power generator on board can significantly increase the rocket dry mass thus limiting the achievable speed. Two physical factors that stand against our dream of the stars are thermodynamics and radiation hazard. Heat-disposing radiator also increases the rocket dry mass. Interstellar gas turns into oncoming flux of hard ionizing radiation at a relativistic speed of the rocket while the oncoming relativistic interstellar dust grains can cause mechanical damage. Economy and psychology will play a decisive role in voting for or against the manned interstellar flights, Comment: 19 pages, 5 figures, acce[ted for publication in Acta Astronautica July 2018 article reference AA6993

We observed and studied strong reduction of optical reflection from the surface of InP wafers after high-temperature annealing. The effect is observed over a wide range of the incident wavelengths, and in the transparency band of the material it is accompanied by increasing transmission. The spectral position of a minimum (almost zero) of the reflection coefficient can be tuned, by varying the temperature and the time of annealing, in the spectral range between 0.5 and 6 eV. The effect is explained by the formation of a uniform oxide layer, whose parameters (thicknesses and average index) are estimated by detailed modeling., Comment: 20 pages, 11 figures, submitted to Journal of Applied physics

Implementation of a semiconductor as a scintillator with a lattice-matched surface photo-diode for radiation detection requires efficient luminescence collection. Low and heavily doped bulk n-InP has been studied to optimize luminescence transmission via photon recycling., Comment: 2 pages, 2 figures, Frontiers in Optics, JTuA33, Rochester, NY, September 24-28, 2010

Interaction is the mode of being of material things amid other material things and the driving force of change and wholeness. Through mutual influence, changes of interacting things become interdependent and their properties interrelated, which leads to formation of ensembles - material wholes of correlated things, where the mode of being of a particular component depends on the modes of being of all other components and vice versa. Every ensemble attains its wholeness and becomes a physical body through togetherness of interrelated components coexisting as a collective being with mutually restrained internal motion. Properties of ensembles on all structural levels of matter composition emerge through the collective being of components., Comment: 37 pages, 1 figure, changed content, added references

A method for displaying volumetric images, which exploits our binocular vision and does not require eyewear, is discussed. The display can be rendered as a matrix of pivoting micromirrors irradiated by a light beam; each micromirror focuses its pixel beams to the same point of displayed volumetric image. 3D perception of image can be achieved by scanning the point of beams intersection over a virtual surface of displayed image in space., Comment: 12 pages, 5 figures

From the point of view of radiation safety, interstellar space is not an empty void. Interstellar gas and cosmic rays, which consist of hydrogen and helium nucleons, present a severe radiation hazard to crew and electronics aboard a relativistic interstellar ship. Of the two, the oncoming relativistic flow of interstellar gas produces the most intence radiation. A protection shield will be needed to block relativistic interstellar gas that can also absorb most of the cosmic rays which, as a result of relativistic aberration, form into a beamed flow propagating toward the front of the ship., Comment: 16 pages, 4 figures, minor grammar corrections, references added, submitted to Acta Astronautica