Solution of nonlinear boundary value problems—X: The false transient method

The solution of a nonlinear boundary value problem may be found by solving a pertinent transient equation until the solution ceases to change significantly (the false transient method). The method is used to get a solution of a strongly nonlinear diffusion problem as well as towards solution of equations arising in the boundary layer theory. If multiple solutions occur the false transient method is not capable of calculating all profiles. For the boundary layer problems it is difficult to construct a reliable false transient equation if it is not based on a physically “sound” transient model.     

Collapse-revival Phenomenon in the Jaynes-Cummings Model Interacting with the Multiphoton Holstein-Primakoff SU(2) Coherent State

Abstract

We have analysed the behaviour of the atomic population inversion of the two-level atom interacting with a single-mode field initially prepared in the multiphoton Holstein-Primakoff SU(2) coherent state. It is shown that the behaviour of the atomic inversion depends on the parameters characterizing the initial state of the field. In particular, the atomic inversion can exhibit periodical oscillations as well as the collapse-revival phenomenon.     

Diffractive-optics-based sensor as a tool for detection of biocompatibility of titanium and titanium-doped hydrocarbon samples

Adsorption of the elongated human plasma fibrinogen (HPF) and globular human serum albumin molecules on a titanium-based surface is monitored by analyzing permittivity and optical roughness of protein-modified surfaces by using a diffractive optical element (DOE)-based sensor and variable angle spectro-ellipsometry (VASE). Both DOE and VASE confirmed that fibrinogen forms a thicker and more packed surface adlayer compared to a more porous and weakly adsorbed albumin adlayer. A linear relation of the permittivity (ε(')) and dielectric loss (ε(')) was found for some of the dry titanium-doped hydrocarbon (TDHC) surfaces with excellent HPF adsorption ability. We discuss some aspects of TDHC's aging and its possible effects on fibrinogen adsorption.     

50-nm local anodic oxidation technology of semiconductor heterostructures

A novel approach to local anodic oxidation technique, which leads to approximately equal 50 nm wide line patterns, is described. The technique is utilized to prepare quantum point contact on a low-mobility semiconductor heterostructure. Transport measurements show quantized conductance in zero magnetic field at 4.2 K thanks to very short one-dimensional constriction. The technique is also used for the definition of low-to-room temperature sub-micrometer Hall probes to show its applicability for the room temperature applications. The magnetic-field resolution and the sensitivity of the probes are evaluated in dependence of the probe dimensions, bias current, and temperature. The 200-nm probe shows magnetic-field resolution of 47 microT/(Hz)(1/2) at 140 Hz and at 4.2 K, when it is driven by 5 microA bias current. The novel approach is promising for the development of the future nano-devices operated both at low and room temperatures. To our knowledge, local anodic oxidation technique applied directly to shallow semiconductor heterostructure has been successfully used for the room temperature application for the first time.     

Micro-contacted self-assembled tungsten oxide nanorods for hydrogen gas sensing

Electron beam lithography was used to fabricate platinum μ-contacts over tungsten oxide nanorods formed on a mica substrate. This made possible the measurement of sensorial response of these self-assembled tungsten oxide nanorods to hydrogen gas for the first time. The nanorods were prepared by thermal evaporation from an oxide source. Consequently, two types of conductometric sensors were assembled: a) percolating network of nanorods and b) set of individually contacted WO₃ nanorods. The preparation procedures are described in detail and the comparison of response of both types of assemblies is given. The first sensorial measurements revealed a good response of the b) type of sensor and the minimum repeatedly detected concentration of H₂ was 50 ppm.     

A note on Computing simple bifurcation points

A direct method computing simple bifurcation points or isola formation centres is suggested. It is based on an improved implementation of the method published in Computing 35, 277–294 (1985) by G. Pönisch.     

Industrial deployment of multi-agent technologies: review and selected case studies

This paper reports on industrial deployment of multi-agent systems and agent technology. It provides an overview of several application domains and an in-depth presentation of four specific case studies. The presented applications and deployment domains have been analyzed. The analysis indicates that despite strong industrial involvement in this field, the full potential of the agent technology has not been fully utilized yet and that not all of the developed agent concepts and agent techniques have been completely exploited in industrial practice. In the paper, the key obstacles for wider deployments are listed and potential future challenges are discussed.