H. Manuszkiewicz

The triple point of nitrogen

We present accurate measurements of the triple point of nitrogen. The quality of this triple point is once more confirmed, and its temperature value is found to be T90 = 63.152 6 K (expanded uncertainty U = 0.30 mK, reproducibility better than 0.1 mK). This is the first direct determination of this point on ITS-90 since the introduction of the scale. This point is useful as a non-uniqueness checkpoint.

A new type of a small cell for the realization of the triple point of mercury

Miniature glass and stainless-steel cells have been made at the Institute of Low Temperature and Structure Research for the realization of the triple point of mercury (T90 = 234.3156 K) to be used for the calibration of capsule-type standard platinum resistance thermometers. This paper gives details on the construction of these cells and some measurement results obtained at the triple point of mercury.

Hysteresis effect in the α-β transition of solid oxygen

Abstract Results of the heat capacity measurements of solid oxygen in the region of the α-β transition are presented. Using the methods of the highest (i.e. better than 1 mK) accuracy of temperature determination, we have found a presence of the latent heat (90 J mol−1) and the hysteresis effect in the transition. Moreover, we discovered that the sharp peak of the heat capacity in the α-β transition has a temperature width of about 50 mK, being composed of two maxima separated by the value of about 20 mK.

Data-acquisition programming under MS-Excel®

Very few people seem to be aware that the well-known spreadsheet program MS-Excel® is also capable of communicating with instruments, and that one can write ones own data-acquisition program without having to take care additionally of importing/exporting data to and from Excel. An outline will be given, with examples taken from a working program, of how to take advantage of this somewhat unexpected aspect of the spreadsheet program.