This paper describes the results of nano-order accuracy contouring control by quadrant glitch compensation for a feed drive system with eight grooved linear ball guide. Three kinds of compensation methods are applied and compared in this study. Those are; 1) repetitive control technique, 2) disturbance observer, and 3) combination of the both. As the results of experiment, the first method decreases the height of quadrant glitch to 0.5 nm by 5 times repetitive compensations. The second method also decrease the height of quadrant glitches to 2 nm, and the third method also can decrease the height to 0.5 nm with repetitive compensation at first time. It is confirmed that the nano-order contouring accuracy can be achieved by combination of the eight grooved linear ball guide and quadrant glitch compensations.

It has been reported that porous aerostatic bearings behave as if they were operating at a clearance larger than the measured bearing clearance, leading to pressure decrease within the gap and to flow rate increase. This implies that it is difficult to predict the bearing performance theoretically at a design stage, because bearing clearances effective for the design are not known. For one porous metal and three porous carbon bearings, theoretical air film pressures calculated by using the finite element method are compared to experimental ones and it is shown that applying an additional gap is a simple way to compensate the difference in the pressure between theory and practice. Taking into consideration the fact that the porous surface texture resembles Plateau texture, it is reasonable to apply the additional gap of the same magnitude to the parameters derived from the areal material ratio curve, in particular, for porous carbon bearings.

We present a production process and electrical gain properties of the gas electron multiplier (GEM) fabricated by using a technique of low temperature co-fired ceramics (LTCC). The LTCC-GEM is one of the gaseous ionization detectors working as a proportional counter or like a Geiger-Müller tubes. The LTCC-GEM was made of Au-pasted LTCC insulator sheet of 100 μm-thickness, and many through-holes with a diameter of 100 μm and a pitch of 200 μm were formed on the sheet. The holes were drilled with a mechanical punch process, which can significantly reduce the load to our environment comparing to the chemical etching processes. The LTCC was employed to prevent the breakdown or short-circuit between two electrodes of the GEM by abnormal discharges. The electrical gain was obtained as a function of the applied voltage between GEM electrodes with 5.9 keV X-rays and the highest gain we achieved was about 20000 at 750 V. Although more than 1000 discharges were observed during the experiment, the LTCC-GEM was not broken down as we expected.