28 research outputs found

    Notes on Hidden Mirror World

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    A few remarks on Dark Matter (DM) models are presented. An example is Mirror Matter which is the oldest but still viable DM candidate, perhaps not in the purest form. It can serve as a test-bench for other analogous DM models, since the properties of macroscopic objects are quite firmly fixed for Mirror Matter. A pedagogical derivation of virial theorem is given and it is pointed out that concepts of virial velocity or virial temperature are misleading for some cases. It is shown that the limits on self-interaction cross-sections derived from observations of colliding clusters of galaxies are not real limits for individual particles if they form macroscopic bodies. The effect of the heating of interstellar medium by Mirror Matter compact stars is very weak but may be observable. The effect of neutron star heating by accretion of M-baryons may be negligible. Problems of MACHOs as Mirror Matter stars are touched upon.Comment: Latex, revtex, 24 pages, 1 figure, references updated and adde

    ΠŸΠΎΡ€ΠΈΡΡ‚Ρ‹ΠΉ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ‚ для Π³Π΅Ρ‚Π΅Ρ€ΠΎΠ³Π΅Π½Π½ΠΎΠ³ΠΎ ΠΊΠ°Ρ‚Π°Π»ΠΈΠ·Π°

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    A effect of the duration of mechanochemical activation process on morphology and particle size distribution of composite powder Cu-13 mass% Al has been investigated by quantitative stereological analysis. It has been found that intensive mechanical failure of particles and increased powder dispersion is directly related to the formation of brittle Cu9Al4 intermetal-lide. Hydraulic characteristics of porous elements for catalytic membranes obtained by hydration hardening of composite powder Cu-13 mass% Al in the form of an 80-100 ΞΌm thick layer on porous titanium discs have been investigated. It was established that the average pore size and permeability coefficient nonmonotonically depend on the particle size of the powder.ΠœΠ΅Ρ‚ΠΎΠ΄ΠΎΠΌ количСствСнного стСрСологичСского Π°Π½Π°Π»ΠΈΠ·Π° исслСдовано влияниС Π΄Π»ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΡΡ‚ΠΈ процСсса мСханичСского активирования Π½Π° ΠΌΠΎΡ€Ρ„ΠΎΠ»ΠΎΠ³ΠΈΡŽ ΠΈ Π΄ΠΈΡΠΏΠ΅Ρ€ΡΠ½ΠΎΡΡ‚ΡŒ частиц ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ‚Π½ΠΎΠ³ΠΎ ΠΏΠΎΡ€ΠΎΡˆΠΊΠ° состава Cu-13 мас.% Al. УстановлСно, Ρ‡Ρ‚ΠΎ интСнсивноС мСханичСскоС Ρ€Π°Π·Ρ€ΡƒΡˆΠ΅Π½ΠΈΠ΅ частиц ΠΈ ΡƒΠ²Π΅Π»ΠΈΡ‡Π΅Π½ΠΈΠ΅ диспСрсности ΠΏΠΎΡ€ΠΎΡˆΠΊΠ° нСпосрСдствСнно связано с Ρ„ΠΎΡ€ΠΌΠΈΡ€ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Ρ…Ρ€ΡƒΠΏΠΊΠΎΠ³ΠΎ ΠΈΠ½Ρ‚Π΅Ρ€ΠΌΠ΅Ρ‚Π°Π»Π»ΠΈΠ΄Π° Cu9Al4. Π˜ΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ‹ гидравличСскиС характСристики пористых элСмСнтов для каталитичСских ΠΌΠ΅ΠΌΠ±Ρ€Π°Π½, ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Π½Ρ‹Ρ… ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΎΠΌ Π³ΠΈΠ΄Ρ€Π°Ρ‚Π°Ρ†ΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ твСрдСния ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ‚Π½ΠΎΠ³ΠΎ ΠΏΠΎΡ€ΠΎΡˆΠΊΠ° Cu-13 мас.% Al Π² Π²ΠΈΠ΄Π΅ слоя Ρ‚ΠΎΠ»Ρ‰ΠΈΠ½ΠΎΠΉ 80-100 ΠΌΠΊΠΌ Π½Π° пористых Ρ‚ΠΈΡ‚Π°Π½ΠΎΠ²Ρ‹Ρ… дисках. УстановлСно, Ρ‡Ρ‚ΠΎ срСдний Ρ€Π°Π·ΠΌΠ΅Ρ€ ΠΏΠΎΡ€ ΠΈ коэффициСнт проницаСмости Π½Π΅ΠΌΠΎΠ½ΠΎΡ‚ΠΎΠ½Π½ΠΎ зависят ΠΎΡ‚ Ρ€Π°Π·ΠΌΠ΅Ρ€Π° частиц ΠΏΠΎΡ€ΠΎΡˆΠΊΠ°

    NOx conversion in La0.85Sr0.15Co0.03Mn0.97O3+d-Ce0.9Gd0.1O1.95 porous cell stacks infiltrated with Pt

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    Porous cell stacks with composite electrodes of La0.85Sr0.15Co0.03Mn0.97O3+d and Ce0.9Gd0.1O1.95 were characterized for the electrochemical reduction of NO in net oxidizing atmosphere in absence or presence of propene in the feed gas. No NOx was converted when the porous cell stacks were at OCV or when polarized. However, when the cells were infiltrated with Pt, an effect of this was observed. It was shown that Pt had a very positive effect on the NOx removal properties of the porous cell stacks, and that NOx could be removed both at OCV or when the porous cells stacks was polarized, both in the absence or presence of propene under net oxidizing conditions. The porous cell stacks was also investigated using electrochemical impedance spectroscopy. It was shown that the impedance data could be de-convoluted into four arcs. Each arc could be fitted with a constant phase elements in series with a resistor. The arcs could be attributed to physical processes
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