80 research outputs found
Monte Carlo and molecular dynamics studies for the colour rewritable films
The structure of the developers plays an important role in the colouring/decolouring
process for the colour rewritable films. We study the chain-like
polymers structure of the developer through both the Monte Carlo and
molecular dynamics simulations. In these simulations we focus our attention
on the thermal (temperature) effects as well as the effective interaction
between developers (chain-like polymers), and with these how the lamellar
structure can be constructed when the system is quenched from high
temperature (low density) to low temperature (high density). We found the
transition of the states from a disordered state to an aggregated state at
a temperature (282 K). We obtained the lamellar structure in a preferable
condition of the potential parameter, while in either smaller or larger interactions,
it is rather difficult for the developer chains to form lamellar structures.Структура проявників відіграє важливу роль в процесі забарвлення/знебарвлення для кольорових записуючих плівок. Ми вивчаємо ланцюжковоподібну полімерну структуру проявника методом Монте Карло і молекулярної динаміки. В цих моделюваннях ми зосереджуємо увагу як на термічних (температурних) ефектах так і на ефективній взаємодії між проявниками (ланцюжково подібними полімерами)
і на тому як шарувата структура може бути сконструйована, коли система є різко охолоджена від високої температури (низької густини) до низької температури (високої густини). Ми знайшли перехід станів з невпорядкованого стану до агрегатного стану при температурі (282 К). Ми отримали шарувату структуру при певній умові потенціального параметра, тоді як при слабких і сильних взаємодіях шарувата структура проявника формується важко
Power exhaust concepts and divertor designs for Japanese and European DEMO fusion reactors
Concepts of the power exhaust and divertor design have been developed, with a high priority in the pre-conceptual design phase of the Japan-Europe broader approach DEMO design activity (BA DDA). Common critical issues are the large power exhaust and its fraction in the main plasma and divertor by the radiative cooling (P radtot/P heat 0.8). Different exhaust concepts in the main plasma and divertor have been developed for Japanese (JA) and European (EU) DEMOs. JA proposed a conventional closed divertor geometry to challenge large P sep/R p handling of 30-35 MW m-1 in order to maintain the radiation fraction in the main plasma at the ITER-level (f radmain = P radmain/P heat ∼ 0.4) and higher plasma performance. EU challenged both increasing f radmain to ∼0.65 and handling the ITER-level P sep/R p in the open divertor geometry. Power exhaust simulations have been performed by SONIC (JA) and SOLPS5.1 (EU) with corresponding P sep = 250-300 MW and 150-200 MW, respectively. Both results showed that large divertor radiation fraction (P raddiv/P sep 0.8) was required to reduce both peak q target (10 MW m-2) and T e,idiv. In addition, the JA divertor performance with EU-reference P sep of 150 MW showed benefit of the closed geometry to reduce the peak q target and T e,idiv near the separatrix, and to produce the partial detachment. Integrated designs of the water cooled divertor target, cassette and coolant pipe routing have been developed in both EU and JA, based on the tungsten (W) monoblock concept with Cu-alloy pipe. For year-long operation, DEMO-specific risks such as radiation embrittlement of Cu-interlayers and Cu-alloy cooling pipe were recognized, and both foresee higher water temperature (130 °C-200 °C) compared to that for ITER. At the same time, several improved technologies of high heat flux components have been developed in EU, and different heat sink design, i.e. Cu-alloy cooling pipes for targets and RAFM steel ones for the baffle, dome and cassette, was proposed in JA. The two approaches provide important case-studies of the DEMO divertor, and will significantly contribute to both DEMO designs
A tentative Replica Study of the Glass Transition
We propose a method to study quantitatively the glass transition in a system
of interacting particles. In spite of the absence of any quenched disorder, we
introduce a replicated version of the hypernetted chain equations. The solution
of these equations, for hard or soft spheres, signals a transition to the glass
phase. However the predicted value of the energy and specific heat in the glass
phase are wrong, calling for an improvement of this method.Comment: 9 pages, four postcript figures attache
Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture II: Intermediate Scattering Function and Dynamic Susceptibility
We have performed a molecular dynamics computer simulation of a supercooled
binary Lennard-Jones system in order to compare the dynamical behavior of this
system with the predictions of the idealized version of mode-coupling theory
(MCT). By scaling the time by the temperature dependent -relaxation
time , we find that in the -relaxation regime and
, the coherent and incoherent intermediate scattering functions, for
different temperatures each follows a -dependent master curve as a function
of scaled time. We show that during the early part of the -relaxation,
which is equivalent to the late part of the -relaxation, these master
curves are well approximated by the master curve predicted by MCT for the
-relaxation. This part is also fitted well by a power-law, the so-called
von Schweidler law. We show that the effective exponent of this power-law
depends on the wave vector if is varied over a large range. The early
part of the -relaxation regime does not show the critical decay
predicted by MCT. The -dependence of the nonergodicity parameter for
and are in qualitative agreement with MCT. On the time
scale of the late -relaxation the correlation functions show a
Kohlrausch-Williams-Watt behavior (KWW). The KWW exponent is
significantly different from the effective von Schweidler exponent . At low
temperatures the -relaxation time shows a power-law behavior
with a critical temperature that is the same as the one found previously for
the diffusion constant [Phys. Rev. Lett. {\bf 73}, 1376 (1994)]. The critical
exponent of this power-law and the von Schweidler exponent fulfill the
connection proposed by MCT between these two quantities. We also show that theComment: 28 Pages of REVTEX, Figures available from W. Ko
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