Sumitomo Heavy Industries (Japan)

Abstract In recent years, the electrification of automobiles and the studies to electrify also aircraft have accelerated as a measure against global warming, necessitating improvements in motor efficiency and power density to reduce CO 2 emissions. The possibility to increase the motor’s rotation speed is, a key factor in enhancing power density. However, high-speed rotation means that higher operative frequency are used thus increasing eddy currents and iron loss. To mitigate these effects, thin ribbons, powders, and thin magnetically soft wires are effective stator materials. Yet, the magnetic properties of these materials deteriorate when bent to form motor components, making it essential to consider the impact of bending stress on magnetic properties during the motor design stage. This study investigates the effect of bending stress on the magnetic properties of thin wire magnetic materials (electrical steel) using the coaxial H coil method. The magnetic properties and iron loss curves for various bending radii R were determined using this method. The findings of this study will influence the design of motors using thin wire magnetic materials.

Abstract The high current density of HTS material allows electromagnet to induce sufficiently strong magnetic field without relying on any iron core. This permits the design of air-cored cyclotron, where the absence of iron core brings the properties of light-weight and high field reproducibility, making it an ideal medical cyclotron to be installed inside hospitals. However, the cyclotron coil system need to induce highly accurate field while satisfying the engineering restriction from the HTS coil. Compact size, small fringe field and minimum fabrication cost are also desirable at the same time. A HTS coil system of air-cored cyclotron is designed with the above restrictions taken into consideration. Multiple beam type accelerations that are required for medical RI production are simulated, in order to verify the usefulness of this design. In this work, the coil system design, the magnetic field and the HTS coil properties are presented. The feasibility of actual fabrication and in-hospital installation is discussed.

This paper is a review for the 18<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> conference of International Workshops on Junction Technology (IWJT), held in Shanghai on 8<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> and 9<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup>, March 2018. It is the 8 time for IWJT to be held in Shanghai. Figure 1 shows the conference venue.

Abstract Pulse tube (PT) cryocoolers are extensively utilized in various applications, including dilution refrigerators for quantum computers and physical property measurement systems that require minimal mechanical vibration-induced noise. In the field of physical and chemical applications, there is a growing need for enhanced first stage cooling capacity. To address this demand, Sumitomo Heavy Industries (SHI) has developed RP-182C2S as an upgrade to our existing 1.5 W 4 K PT cryocooler, RP-182B2S. This upgrade offers a substantial improvement in first stage cooling capacity, increasing its specification from 36 W at 48 K to 42 W at 45 K, while maintaining the specific second cooling capacity and interface on the cylinder side. From a vibration standpoint, increasing the cooling capacity can potentially have negative effects on vibration characteristics. This is primarily due to factors such as the larger cylinder size and changes in operating pressure conditions. Another factor to consider is the alteration in the gas intake and exhaust direction of the cold head piping, transitioning from a horizontal design (used in 1.0 W 4 K PT cryocoolers) to a vertical design (implemented in 1.5 W 4 K PT cryocoolers). These modifications may also impact the vibration characteristics. Moreover, while vibration measurements of cryocoolers are typically conducted in room temperature environments, it is essential to perform such measurements in cryogenic environments to achieve more accurate and realistic results. In this study, we developed a test bench enables vibration measurements in a second stage condition at 4.2 K. We used this setup to conduct vibration measurement on RP-182C2S as well as RP-182B2S and RP-082B2S which served as the comparative cryocoolers. The evaluation results indicate that RP-182C2S demonstrates nearly identical vibration characteristics to RP-182B2S in terms of displacement and acceleration. Additionally, it was suggested that adjusting the direction of the piping can help mitigate vibration levels in a specific direction.