In the near future, expanding demand on electric power of the metropolis will force us to introduce very high density energy transport systems of considerable distance because appropriate site for GW class power plant is now quite limited and only found in a furtherest corner of the main land. This article discusses some engineering problems on refrigeration of expected superconducting or cryoresistive cables. With the present status of fidelity of cryogenic machineries in mind, we did not try to get the optimum values for main parameters of cooling pipes in haste, for instance, diameter, mass flow rate, distance between refrigerating plants and so on. The stresses are put on the points that technical restrictions from first stage cooling-down and safeguard design against faults of coupled system of cryogen and electric power are the main factors to determine the size of the cooling pipe. The main issue is to select out the best combination of conductor, cryogen and phase of the cryogen. Usage on two phase flow is limited to the pipes of less than 1-km length. Comparison between supercritical and sub-cooled flow is a delicate one because cooling abilities of both is approximately the same, but sub-cooled flow is the choice in respect of local thermal stability. Several rough sketches for the long range refrigerating systems are put forth in the article. In view of thermal stability, there exists a dilemma, that is, if we adopt two phase flow, systems are locally more stable but put in hazard in its full length operation. A design to reconciliate this dilemma is presented.
Superconducting apparatus which are used or to be used in High Energy Physics are reviewed. Large superconducting dc magnets in the world are tabulated with their main parameters. Special features on each magnet are discussed. Superconducting quadrupole magnets and bending magnets which are intended to use in real high energy beam lines are also discussed. A brief description on the problems in applications of ac superconductivity such as accelerator magnets is given. In the final section, a prospect of use of such superconducting apparatus in High Energy Physics of Japan is also given.
This paper describes levitation characteristics of high speed magnetically suspended trains. In the case of magnetic repulsion type with tracked coils, transverse force caused by the displacement of transverse direction of coil center increases with increasing its displacement. On the other hand, however, lifting force decreases in proportion to that displacement. In order to study the stability of this method, lifting and transverse forces for various current configurations are calculated by the approximation of infinitely long line current. For the levitation with magnets placed on both sides of train as conventional wheels, it is shown that lifting and transverse forces are influenced by polarities as transverse displacement of these magnets and the null flux method proposed by Powell and Danby has a good stability against transverse displacement.
In the previous paper, lifting and transverse forces were calculated in the case of vehicle coils and tracked coils placed in parallel horizontally. In order to keep the train its equilibrium position against transverse displacement, Powell and Danby proposed the use of vertical stabilizing coils. In this paper, their proposal and its modificatios are treated and then slanting configuration is offered to get transverse stability. The horizontal components of slanting ground coils act as lifting loops and the vertical components as stabilizing loops. The slanting, therefore, is the configuration which is able to obtain lift and stability at the same time. It is shown that good stability is obtained at some cases of slanting configurations by the approximation of infinitely long line current.
Mechanical properties, microstructures, saturation flux density, and electrical resistance were investigated of 17wt%Cr-11wt%Ni-2wt%Mo and 18wt%Cr-15wt%Ni-2wt%Mo stainless steels deformed at 4.2°K. Elastic limit, tensile strength, and elongation were 47.5kg/mm2, 135kg/mm2, and about 30% for the annealed 17wr%Cr-11wt%Ni-2wt%Mo, and 55kg/mm2, 125kg/mm2, and about 38% for the annealed 18wt%Cr-15%Ni-2wt%Mo, respectively. With increasing the percent of pre-strain at 295°K, the elongation and the elastic limit increased and the hardening coefficient and the saturation flux density decreased for 17wt%Cr-11wt%Ni-2wt%Mo. A slight martensite induced magnetically was observed in the 17wt%Cr-11wt%Ni-2wt%Mo exposed previously under a magnetic field of 80kOe for 6min 4.2°K. A discontinuous increase in the electrical resistance was observed during deformation at 4.2°K for each steel. The microstructures of the above mentioned steels discussed.