A New bit cofinement method using film thickness modulation (FTM) has been studied on the Bloch-line (BL) memory to make the BL pair propagation cmmon to both sides of the stripe domain wall. Since it is necessary to make the modulation pattern edge smooth for low drive-field propagation, we used tapered resist patterns for the ion milling mask and carried out the milling to fabricate 100 nm thickness modulation in an O₂ atmosphere (10^-6 Torr). BL pair propagation was tested with applying the trianglar bias pulsed field with 100 ns rise time and 1000 ns fall time. It was found that the drive field margins did not depend on the propagation direction, because the bit confinement force acts symmetrically on both sides of the domain wall. Furthermore, it was confirmed that the temperature dependece of the drive field margin was larger than that in the conventonal magnetic pattern method.

抄録全体を表示

We have developed a novel railway signal control system using the Internet technology, the system named “Network Signal Control System”. In this paper, we introduce various sensor technologies applied for the signal system. In particular, we have evaluated the system according to the RAMS (Reliability, Availability, Maintainability and Safety) method, and then high reliable data-transmission techniques realized by the popular Internet technology are examined. We also achieve technique to detect missing data by using the “out-of-time flag”, the flag adapted in the data flow. Originally, sensor technologies have significant roles for signal control systems. Several sensing systems are developed and introduced to the signal control system. Moreover, we introduce a novel observation system that is based on the database technology. Server and client system is employed to realize the database, to which every control device transmits its status.
This system has been on service on February 2007. We expect that many sensor technologies will be much useful to improve it.

抄録全体を表示

The Build-up Process is very important in the production of a multilayer printed wiring board (PWB) in electric communication devices. Nowadays, laser and photolithography processes are the main methods used for forming via holes in the polyimide in the Build-up Process. In this study, as a preliminary experiment for via hole formation, etching rates in polyimides were investigated using a plasma etching process with a roll coater instead of previously utilized processes. This was carried out with a reactive ion etching (RIE) discharge, created by applying a low frequency power of 400 kHz to the main roller as a cathode, using O₂ and CF₄ gases. A high dynamic etching rate of 5 μm ·m/min was the target value. The dynamic etching rate increased with the power applied, and the maximum values obtained were 3 and 2 μm ·m/min for polyimide films (25 μm) of Kapton 100H and Upilex S, respectively. To realize a higher density of plasma, a high frequency power of 13.56 MHz was applied to the anode, from which the etching gasses were fed, in addition to the RIE discharge. The etching rate was found to further increase as a result. Moreover, adding N₂ gas to the etching gases increased the etching rate. These results taken together have created the possibility to surmount the target value.

抄録全体を表示