The absolute determination of the 2e/h done by B. N. Taylor et al based on the AC Josephson effect in terms of the emf standard of the National Bureau of Standards is introduced. The voltage intervals between sharp current steps which take place when a Josephson junction is irradiated by microwave power of appropriate frequency is so definitely related to the microwave frequency that the effect might offer a powerfull base of the atomic standard of the emf in the future. This circumstance is explained in conjunction with the present status of the electrical units and attempts on the atomic standards of electrical units.
General description are given on the recent trends of storage, transportation and coldness utilization of liquefied natural gas. Three different types of storage tanks……namely above ground tank, insulated below ground tank and frozen earth tank…are constructed. There are two alternative construction systems of cargotanks of LNG ocean tanker. One is self-supporting type and other is membrane type. We can find many reports on the research and reviews on the coldness utilization of LNG, and no apparent commercial instances of it.
A hydrogen bubble chamber with 200 liters of liquid, 78cm in diameter is under construction at Institute of Nuclear Study, University of Tokyo. A simple Linde refrigeration cycle is provided, as such a system meets the design considerations of this chamber. In order to establish the required capacity of the refrigerator, the static and dynamic heat loads were analyzed. Designing for a cycling rate of two expansions per second gives an estimated total heat load of 920 watt, including safety factors. A refrigerator with a capacity of 1, 000 watt at 26°K, therefore, was designed for this chamber, and brief descriptions of this refrigerator are given. For the precise control of the temperature of the chamber liquid, an elaborate temperature control loop configuration was considered, and the hydrogen temperature circuit schematic is shown.
One of the important factors which stabilize the copper claded superconducting wire is boiling heat transfer from superconducting wire to liquid helium. To improve the cooling effect of stabilized superconducting wire, the cooling effect of the channel (6.3mm wide, 12.83mm long) digged on the surface of copper was investigated. The channel oriented horizontally in liquid helium was effective in nucleate boiling heat transfer but it had little effect on maximum nucleate boiling heat flux qmax, minimum film boiling heat flux qmin and film boiling heat transf