The concepts of $k$-systems, $k$-networks and $k$-covers were defined by A. Arhangel’skiǐ in 1964, P. O’Meara in 1971 and R. McCoy, I. Ntantu in 1985, respectively. In this paper the relationships among $k$-systems, $k$-networks and $k$-covers are further discussed and are established by $mk$-systems. As applications, some new characterizations of quotients or closed images of locally compact metric spaces are given by means of $mk$-systems.
Picea glehnii Masters can grow in strongly acidic volcanic ash soil (pH 3.6) in northern Japan. We compared needle longevity, photosynthetic rate, and concentrations of elements in needles, in mature trees of P. glehnii growing in volcanic ash soil and in brown forest soil (pH 5.4). P. glehnii growing in volcanic ash soil showed suppressed photosynthetic rate and growth by the deficiency in nitrogen compared with its growth in brown forest soil. However, the younger needles of P. glehnii growing in volcanic ash soil maintained a high photosynthetic rate, as a result of large amounts of remobilized nitrogen from senesced needles. Needles of P. glehnii growing in volcanic ash soil did not show deficiencies in Ca, Mg, or K. Moreover, Al was at low levels in the needles, suggesting that P. glehnii was able to avoid Al toxicity by Al exclusion. P. glehnii thus exhibits great ability to adapt to an acidic environment. and M. Kayama, F. Satoh, T. Koike.
A new optical apparatus for in situ monitoring of optical constants of growing (etched) thin films - substrate systems over the large surface area of the sample (ranging from 1 to 2 cm2) was designed, constructed and tested in our group. Namely, the two following devices have been designed: Firstly, InSitu-AreaSampler together with control software has been developed for analysis of an areal homogeneity of thin-film growth during its deposition (or etching). The method is based on the measurement of reflectivity of the sample at selected wavelengths of an incident light. Areal detection is assured (performed) by imaging of the surface of thin film by a CCD chip where each pixel acts as small detector in an independent way. Secondly, the InSitu-SpotSampler was developed for measurement the reflectivity of growing (etched) thin film at one spot on the sample surface but in quasi-continual range of wavelengths (UV-VIS). The results achieved show the usability of this instrument for the in situ measurements of optical constants (index of refraction n, exctinction coefficient k, thickness d) over the whole sample area (cca 1.5 × 1.5 cm2) in a quasi-real time mode. Having this feed-back it is possible to control the deposition process in a more effective way.