Cultural and linguistic problems in the use of authentic textbooks when teaching mathematics in a foreign language

This paper is a part of a longitudinal study focusing on qualitative aspects of learning in a foreign language in the development of cognitive processes in mathematics. The aim of the paper is to present a more complex analysis of textbook-based obstacles to communication. These obstacles originate in the process of vocabulary and grammar acquisition within a particular multicultural and sociocultural context. The study was carried out using mathematics textbooks from English-speaking countries which are used when teaching mathematics in English to Czech students.     

Development of renewed mercury multi-purpose (multi-mode, versatile) microelectrodes, a part of PC-controlled measuring systems (including the PC-ETP)

Information is given about the development of renewed miniaturized mercury multi-purpose (multi-mode) electrodes as an inseparable part of the development of modern polarography and voltammetry; casette-type, pen-type and PC-controlled systems, incl. the polarographic/voltammetric set. According to the experimental behavior and ranges of their radii the regimes of renewed stationary mercury electrodes are divided into three categories – mini-, semimicro- and microelectrodes (mE, sμE and μE). Their spontaneously growing, stepwisely growing, stationary and contracting (compression) modes are schematically outlined. Information on basic functional properties of the discussed renewed mercury semimicro- or microelectrodes using meniscus and microdrop-electrodes, by means of the d. c., anodic stripping and adsorptive stripping voltammetry is given.     

Improved dual photometric-contactless conductometric detector for capillary electrophoresis

A new design of a dual, UV photometric - contactless conductometric detector is described. The separation capillary with an optical window created is pressed onto two semitubular electrodes, 3 mm wide and 2 mm apart. The electrodes form the detection cell of the contactless conductometric detector. An optical fiber, placed in the gap between the conductometric electrodes, brings radiation from the source. The radiation that passes through the separation capillary is recorded by a large-area photodiode. The optical fiber and the photodiode operate the photometric cell which is between the conductometric electrodes. The detector thus permits simultaneous photometric and conductometric detection in the same place of the capillary, while exchanging of the separation capillary is easy and without effect on the detector geometry and performance.     

On the synthesis of chlorine pentafluoride

The reaction between chlorine trifluoride and elemental fluorine was studied in order to find the optimal reaction conditions for the synthesis of chlorine pantafluoride. It has been found that nickel difluoride is a very effective catalyst for the mentioned reaction. The obtained results are expressed as space-time-yield of chlorine pentafluoride.     

The magnitude and reproducibility of the electroosmotic flow in silica capillary tubes

The influence of a number of factors, such as the nature of the buffer, the presence of additives therein, the manufacturing conditions, and the pretreatment of the capillary, on the magnitude and repeatability of the electroosmotic flow (EOF) in silica capillary tubes has been investigated. It was established that the nature of the buffer plays the most significant role in respect of the stability and magnitude of EOF, whereas the conditions used for manufacture and pretreatment of the tubing are less important. The EOF obtained using buffers consisting of tris(hydroxymethyl)aminomethane and ethylenediamine was more repeatable than that obtained using pure phosphate buffers. Buffer additives such as sodium dodecylsulfate, 1-butanol, sodium salts of 1-pentanesulfonic acid and 1-heptanesulfonic acid, altered the magnitude of the EOF only, not its repeatability.     

On the plane gravitational condensor with the positive gravitational constant

The equations of motion for the plane shell consisting of an ideal fluid and creating the de Sitter solution on one side and the static plane symmetric solution of Einstein equations with positive cosmological constant on the other side are derived. Solution of the equation of motion for the case of “plane gravitational condensor” is found and the necessary agreement with the solution of the problem in the caseA = 0 is demonstrated.