Tatsuo Arai

Estimation of personal exposure to ambient nicotine in daily environment

SummaryTo evaluate the actual exposure level of nonsmokers to environmental tobacco smoke (ETS) in their daily life, the exposure level of ambient nicotine was measured with a nicotine personal monitor carried by a nonsmoker. Average exposure levels of nicotine, even in such smoky places as cars, coffee shops and pubs, were less than 45 μg/m3. As a result of all-day monitoring, the highest amount of nicotine inhaled in a day was estimated, in this study, to be up to 310 μg, equivalent to actively smoking 0.31 ordinary cigarettes.

Chemical reaction between hydrogen atoms and electrons on the surface of superfluid 4He

Abstract Two-dimensional mixture of atomic hydrogen and electrons on the surface of superfluid 4 He was realized below 0.5 K. Vibrating capacitor electrometer was employed to show that after the electron capture reaction, H+e − →H − , the product, H − , might penetrate into the bulk liquid.

An ultra low temperature cryostat built with highly conductive copper

Abstract Features of a cryostat under construction in Tokyo and intended for fast operation at ultra low temperatures will be described. Highly conductive copper is used for both of the following reasons. 1. To achieve the ultimately low temperature and 2. To reduce the entropy loss while precooling of the copper nuclear demagnetization stage by a PrNi5 nuclear demagnetization refrigerator, which achieves continuous cooling by means of two stages which are demagnetized alternately.