The Concept of Two Mobilities in Homoepitaxial Growth

A general kinetic concept is introduced which can be used to control growth modes in homoepitaxy. Its basic idea is that during growth of a layer, the characteristics length scale associated with nucleation is deliberately varied. The power of this concept lies in the fact that it can be realized experimentally in a variety of ways and is not restricted to special systems. It helps to understand various effects reported in the literature and may serve as a guideline for future methods of growth manipulation

Conventional and manipulated growth of Cu-Cu(111)

Molecular beam epitaxy of Cu on Cu(111) was studied using thermal energy He scattering, in the temperature range between 100 and 450 K. Three-dimensional growth was observed in the whole temperature range. To determine the onset of various diffusion processes, submonolayer films formed by deposition at low temperature were annealed. Annealing proceeds in two steps. The first step is interpreted as a change in island shape, the second as Ostwald-ripening. A comparison with homoepitaxy on Pt(111) and Ag(111) is made. Growth manipulation was carried out by artificially increasing the island number density via intervention in the nucleation stage of each layer. The procedures applied were temperature reduction during nucleation as well as pulsed ion bombardment. These techniques enabled the convenient growth of good quality films consisting of a large number of monolayers. Finally, the use of oxygen as a surfactant modifying the growth mode was investigated. Under some growth conditions, pre-exposure of the surface to oxygen was found to induce weak He-intensity oscillations during deposition. The quality of the films grown in this way was, however, low

Developing animated 3D scene to render the underwater environment

Three-dimensional modeling today became widespread in various fields: from a simple computer game to the simulation of complex processes. This article includes the description of the process of creation 3D-model the AUV and water area by using the game engine such as Blender and Unity 3D

Manipulation of growth modes in heteroepitaxy: Ni-Cu(111)

Growth manipulation methods, which have been successfully used to improve the growth of homoepitaxialfilms, are applied to molecular beam epitaxy of the heteroepitaxial system Ni/Cu(111). The procedures applied are temperature reduction during nucleation and pulsed ion bombardment during deposition. While the first does not lead to smoother films, the ion beam assisted growth is successful in reducing the film roughness

A comparison of reinforcement learning algorithms in fairness-oriented OFDMA schedulers

Due to large-scale control problems in 5G access networks, the complexity of radioresource management is expected to increase significantly. Reinforcement learning is seen as apromising solution that can enable intelligent decision-making and reduce the complexity of differentoptimization problems for radio resource management. The packet scheduler is an importantentity of radio resource management that allocates users’ data packets in the frequency domainaccording to the implemented scheduling rule. In this context, by making use of reinforcementlearning, we could actually determine, in each state, the most suitable scheduling rule to be employedthat could improve the quality of service provisioning. In this paper, we propose a reinforcementlearning-based framework to solve scheduling problems with the main focus on meeting the userfairness requirements. This framework makes use of feed forward neural networks to map momentarystates to proper parameterization decisions for the proportional fair scheduler. The simulation resultsshow that our reinforcement learning framework outperforms the conventional adaptive schedulersoriented on fairness objective. Discussions are also raised to determine the best reinforcement learningalgorithm to be implemented in the proposed framework based on various scheduler settings

Top-layer superstructures of the reconstructed Pt(100) surface

The structures of the two reconstructed phases of the Pt(100) surface have been studied by high-resolution helium diffraction. In contrast to earlier investigations, we show that for both phases the superstructure in the approximate 〈011〉 direction is not fivefold but much larger. The mean distance between atom rows in the top layer, however, is very close to that of a fivefold superstructure. This supports the description of the surface layer in a model which assumes static oscillations about a flat and equidistant atom arrangement. The results are discussed in comparison with low-energy electron diffraction, scanning-tunneling-microscopy, and x-ray-diffraction results