Properties of WN x /GaAs Schottky contacts prepared by ion implantation of nitrogen

The formation of WN _x /GaAs Schottky contacts using selective ion implantation of nitrogen into the sputtered tungsten film has been demonstrated. The contacts were characterized by Auger electron spectroscopy and current-voltage measurements. The composition of WN _x films and the thermal stability of WN _x /GaAs contacts were investigated. Good thermal stability of WN _x /GaAs contacts compared with a W/GaAs contact was observed after capless rapid thermal annealing at 450, 800 and 950°C for 10 s.     

Diagnostic performance of edited 2HG MR spectroscopy of central glioma in the clinical environment

Magnetic Resonance Materials in Physics, Biology and Medicine - Oncometabolite D-2-hydroxyglutarate (2HG) is pooled in isocitrate dehydrogenase (IDH)-mutant glioma cells. Detecting 2HG by MR...     

Czech project in history of mathematics

The paper describes the Czech project in the history of mathematics which was initiated at the Faculty of Mathematics and Physics of Charles University in Prague at the end of the eighties of the 20th century. Its main aim is to map the development of mathematical research in the Czech lands in the second half of the nineteenth and the first half of the twentieth century. The main result of this project is the production of monographs. These chart out the life and work of some prominent Czech personalities-mathematicians who have had substantial influence on the development of Czech mathematics. The aim of the project, the structure of the monographs and the general method are discussed in the paper.     

Influence of Yag Concentration and Pressing Time on Wear of Si3N4 Based Ceramics

Strength of Materials - Abrasive wear resistance of Si3N4 strongly depends on its microstructure, in particular, grain morphology. In this work, the effects of β-content, β-Si3N4 grain...     

What Business Owners Expect From a Crisis Manager? A Competency Model: Survey Results From Czech Businesses

This competency model of a crisis manager has been developed based on cooperation with managers and experts in the field of crisis management. The brainwriting method was used to generate an overview of the competencies expected of a crisis manager. Using a mind map three basic groups of competencies were developed. The participants used Saaty's method to determine the significance of individual competencies. The different attributes of individual competencies according to the level of their development were established. Finally all individual competencies were assigned a target value which indicates the expected level of competence for the position of a crisis manager. The model of competencies is a practical tool for the establishment of crisis management system in a company.     

TLM modeling of a probe‐coupled cylindrical cavity based on compact wire model in the cylindrical mesh

This article describes an implementation of a compact wire model into the three‐dimensional transmission‐line matrix (TLM) cylindrical mesh for the purpose of an efficient analysis of probe‐coupled cylindrical microwave cavity devices. Because of a cylindrical grid structure and empirical nature of the compact model, this implementation has to take into account a change of wire model parameters with a variable cross section of the TLM nodes through which a wire conductor passes. The model accuracy has been experimentally verified and compared with the corresponding results reached by the TLM method based on a rectangular grid in order to consider its advantages. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

Material and Energy Interactions between Milling Bodies,Milled Particles,and Milling Environment

Changes in particle size, surface state, and composition brought about by planetary and vibration milling of silicon and quartz in various permittivity liquids were investigated. Using a variety of spectroscopic techniques (IRS, XPS, and Mössbauer spectroscopy) the changes in quality of the superficial layers of milled particles have been determined. During energy-intensive milling, the material being milled intensively interacts with the media and milling environment. The nature of the interaction and quality of the surface shell covering the milled particles depend on the reactivity and hardness of the interacting solids and of the milling environment. During planetary milling of silicon with tungsten carbide media, the superficial layers are formed by silicon suboxides and silicon oxide. The thickness of the superficial layer and the share of SiO₂ increase with increasing permittivity of liquids. Milling with steel media results in a more complicated composition of the superficial layer. According to Mössbauer spectra, the iron is present in two main forms: as a magnetically ordered form identical with basic material of balls and in a paramagnetic form as a product of a mechanically stimulated surface reaction between Si and Fe. The presence of the superficial layers on the milled particles of silicon and quartz markedly influences the values of the specific surface area. This influence should be taken into consideration when calculating the specific contamination of the milled powder.     

Martensitic zirconium alloys: Influence of chemical composition on creep characteristics

Results of an extensive investigation of creep in martensitic zirconium alloys are summarized with the aim to show the influence of chemical composition on the main creep characteristics — the steady state creep rate and the time and strain to fracture. The activation energy of creep and the parameter of stress sensitivity of steady state creep rate are determined and possible creep mechanisms as well as creep strengthening mechanisms are discussed. The time to fracture $\text{t}{}_{\mathrm{f}}$, is related to the steady state creep rate ge_s through the Monkman-Grant relation as modified by Dobe? and Milic?ka. The creep fracture shows features different from those of “classical” intergranular cavitation creep fracture. Most probably the creep fracture is controlled by the same deformation mechanism as the creep.