Optimized Design of 8-Figure Null-Flux Coils in EDS Maglev.
The 8-figure null-flux ground coils in EDS (Electro-Dynamic Suspension) including the PLG (combined Propulsion, Levitation and Guidance) system, which can both suspend and propel maglev vehicles simultaneously, have mainly longitudinal and vertical dimensions such as coil pitch and heights of upper and lower coils. In this paper we investigate these dimensions not only to balance the basic performance for levitation, guidance and propulsion, but also to reduce magnetic disturbance of superconducting magnet. By using an optimization program, we induced the relationship between the basic performance and these dimensions. Furthermore, by implementing a modal analysis, we predicted the vibration of superconducting magnet in different pitches, and thereby proposed these dimensions to decrease the vibration.
Study on vibration phenomena of superconducting magnets for MAGLEV
Heat loads occur in the superconducting magnets for Maglev applications due to vibration during train operation. To control this heat load, it is necessary to understand the vibration phenomena in the superconducting magnet. In this study, vibration evaluation and control for superconducting magnets were addressed from both experimental and analytical approaches, and verification tests were conducted with a prototype model. This paper describes verification results for the prototype model and the results for an actual superconducting magnet which was constructed based on the prototype model.
VLA stereoscopy of solar active regions. 2: Altitude, relative motion, and center-to-limb darkening of 20 centimeter emission
A newly developed method of stereoscopic correlation is applied to solar radio maps at a wavelength of 20 cm. On the basis of stereoscopic correlations between radio maps obtained on 6 different days we establish the presence of 66 radio source components associated with 22 active regions. We find the following statistical results for active region source structures at 20 cm: 1. The observed lifetime is consistent with an exponential distribution having an e-folding time scale of greater than 18 days. 2. The average altitude of 20 cm sources is 25 +/- 15 Mm; 90% of the sources are found in heights less than 40 Mm. 3. The average diameter of discrete source structures is 48 +/- 15 Mm, implying a vertical/horizontal aspect ratio of q(sub A) approx. = 0.5. 4. No significant source motion has been found with respect to the standard differential rotation rate of Omega = 13.45 deg - ((3 deg (sin(exp 2)B)). 5. We find a statistical limb darkening, which can be described by the relation (T(sub B)(alpha))/T(sub B)(0)) = 0.4 + ((0.6(cos(exp 2) alpha)) for sources with T(sub B) greater than 0.5 MK. 6. The degree of source polarization is 15% +/- 10% and is independent of source location. 7. Bright sources (greater than or approximately equal to 0.5 MK), or equivalently, long-lived sources (greater than or approximately equal to 5 days) show a systematic variation of their altitude as function of the center-limb distance.