No abstract available

No abstract available

No abstract available

No abstract available

[en] The directed motion of a Brownian particle in a flashing potential with various transition probabilities and waiting times in one of two states is studied. An expression for the average cycle period is proposed and the steady current J of the particle is calculated via Langevin simulation. The results show that the optimal cycle period τ_m, which takes the maximum of J, is shifted to a small value when the transition probability λ from the potential on to the potential off decreases, the maximal current appears in the case of the average waiting time in the potential on being longer than in the potential off, and the direction of current depends on the ratio of the average times waiting in two states.

[en] A sublimation process governs the innermost region of the dusty torus of active galactic nuclei. However, the observed inner radius of the torus is systematically smaller than the expected radius by a factor of ∼1/3. We show that the anisotropy of the emission from accretion disks resolves this conflict naturally and quantitatively. An accretion disk emits lesser radiation in the direction closer to its equatorial plane (i.e., to the torus). We find that the anisotropy makes the torus inner region closer to the central black hole and concave. Moreover, the innermost edge of the torus may connect with the outermost edge of the disk continuously. Considering the anisotropic emission of each clump in the torus, we calculate the near-infrared flux variation in response to a UV flash. For an observer at the polar angle θ_obs = 25⁰, the centroid of the time delay is found to be 37% of the delay expected in the case of isotropic illumination, which explains the observed systematic deviation.

[en] Transport of a particle in a flashing ratchet coupled to a non-Ohmic environment with spectrum ∝ω^μ-1 (0<μ<2) is considered. If the temperature is much less than the barrier height of the ratchet potential and the waiting time of the particle in the potential on is long enough, the current J is evaluated approximately by the step periodic number per cycle. The results show that the maximum of peak for J is a non-monotonous function of μ, the optimal μ appears in the region of superdiffusion. The current in the anomalous ratchet is much larger than in the normal one

[en] The lower end of the solid-vapour transition curve is seldom indicated in thermodynamics textbooks, and sometimes erroneously. We show, on general model independent grounds, that the sublimation curve reaches the origin in the (T,p) plane, with a quasi-universal behaviour. (author)

[en] Purpose: To inject pellets at high speed without melting or sublimating not-injected pellets even at a long pellet injection interval. Constitution: In the conventional multi-shot pellet injection device, the pellet injection interval is set depending on the plasma retention time. However, as the pellet injection interval is increased, not-injected pellets are melted or sublimated due to the introduced heat of acceleration gases supplied from an acceleration gas introduction pipe to give an effect on the dimensional shape of the pellets. In view of the above, a plurality of pellet forming and injection portions each comprising a carrier, an injection pipe and a holder are disposed independently of each other and pellets are formed and injected independently to thereby prevent the thermal effects of the acceleration gases. (Kamimura, M.)

[en] Flashing has been analyzed for a water column with an initial hydrostatic head of 0.55 bar in a vertical riser with flow cross-section of 950 x 120 mm² under low mass flux, low subcooling and low heat flux conditions. In this paper flashing is defined as self-evaporation due to all kind of pressure-drops, and geysering is defined as a kind of repeated vaporization, which is propagated by the pressure-drop due to a decreasing hydrostatic head. The instability phenomenon in the test facility provides information for extending the up to now one-dimensional geysering models. Due to the two-dimensional flow structure in the vertical test section one observes geysering with flow circulation. The two-dimensional geysering therefore shows smaller pressure movements and faster pressure recovery as in the case of one-dimensional geysering. In the two-dimensional case both the geysering frequency and the geysering strength enhance with increased energy input for the geysering. Furthermore the geysering frequency increases with reduced initial hydrostatic head. (author)