Freeze-etching of dispersions without contamination of the fracture faces.

The physical processes occuring while the fracture face of a dispersion is being freeze-etched are described and the resulting opportunities for elimination of contamination phenomena are discussed. An anticontamination device which can be used in combination with a drop freeze-fracture apparatus is described. The main advantages of the device, high effectiveness and great simplicity, are demonstrated by several practical examples.     

New method for thermo-optical modeling in liquid crystals

To investigate the thermo-optical effect in liquid crystal(s) (LC)s the statistical methods of experiment planning are applied. The experiment was conducted in accordance with the technique of orthogonal central compositional planning. In the course of the experiment, physical parameters (scanning velocity, laser beam intensity, LC temperature) have been varied on five levels. The obtained mathematical model describes the dependence of light-scattering texture dimensions in the LC layer onphysical parameters of information by thermo-optical registration. Such a model allows us to determine the suitable function model to obtain the preset dimensions of the light-scattering texture in a LC layer.     

Noninvasive Quantification of Cutaneous Oedema in Patch Test Reactions by Fiber Optic Near-Infrared Fourier Transform Raman Spectroscopy

The major aim of the present study was to quantitatively differentiate various degrees of positive patch test reactions by estimating relative water content noninvasively using fiber optic near-infrared Fourier transform (NIR-FT) Raman spectroscopy. The specific intent was to examine its technical applicability and reproducibility in reading patch tests at 48 and 72 hr. Instrumental measurements at 63 patch test sites were compared visually in 19 patients with suspected allergic contact dermatitis. Raman spectra were measured in vivo in skin reacting to patches on the back using a fiber optic technique. Negative (–), doubtful (?+) and positive patch test reactions (+; ++/+++) could be separated by means of measured differences in absolute values of the 3250 cm^–1 peak (ratio I₃₂₅₀/I₂₉₄₀): at 48 hr the mean increases were 0.31(–), 0.40(?+); 0.45(+); 0.69(++/+++) and at 72 hr they were 0.31(–); 0.34(?+); 0.42(+); 0.60(++/+++). At 48 hr significant differences (p<0.05) were shown between all reactions, but not between negative and doubtful reactions at 72 hr. These findings indicate that cutaneous oedema in patch test reactions can be noninvasively quantified based on positive patch test reactions by NIR-FT Raman spectroscopy, with continuous data grading of reaction intensity suitable for clinical studies at 48 and 72 hr. We also demonstrated good technical reproducibility of patch test reactions evaluation by NIR-FT Raman spectroscopy at 48 and 72 hr, showing that this method can be used to monitor the dynamics of these reactions and display the results spectroscopically.     

Circuit Level Concurrent Error Detection in FSMs

Finite state machines (FSMs) are contained in many building blocks of digital electronic circuits. Such electronic circuits are prone to transient errors, caused e.g. by cosmic radiation, and to permanent errors. In this article, the authors give an overview of known error detection methods for FSMs. One method (dependent state encoding for dynamic error detection) is described in detail, as well as the problems arising when the method is applied to a practical example. Additionally, the authors propose a modification of the method above. For several benchmark circuits, this modification shows better results, compared to the state-of-the-art implementation.