Development of Cassegrain type 0.9-m collimator

Abstract

Collimator is essential to evaluate and assemble the other telescopes. Its diameter should be larger than that of the target telescope for the correct use. We are currently developing the Cassegrain type collimator of which diameter is 0.9 m. The primary mirror is light-weighted so that its weight is only 70 kg. Due to its structure, the primary mirror can be supported only at the backside of the mirror. This mirror is tested with the combination of null Hartmann test and interferometer. The secondary mirror is tested with a Hindle method. This method requires 600 mm high quality spherical mirror. The distance between the primary and secondary mirror is maintained by the Carbon composite material. The assembly of two mirrors is carried out by the computer aided alignment method. The whole structure is designed to maintain the performance of the collimator under +/-5 degrees of temperature variation.

CO preferential oxidation on cordierite monoliths coated with Co/CeO2 catalysts

“…It is known that the XP spectrum of the Co 2þ compound exhibits a pronounced satellite peak on the highenergy binding energy side of main peak. This satellite is not present in the diamagnetic Co 3þ compound [7,11]. Fig.…”

“…Due to their redox properties, supported cobalt oxides have been traditionally studied for CO oxidation applications [7]. Cobalt suported on zirconia, ceria, and the mixed oxide CeO 2 e ZrO 2 resulted efficient catalysts for the CO preferential oxidation [8,9].…”

Preferential oxidation of CO in H2 over Co3O4-CeO2 catalysts

“…In the XRD patterns, only reflections of Co 3 The Co 3 O 4 -CeO 2 catalyst with low cobalt content (5 wt.%~20 wt.%) had been reported to be highly active in the CO oxidation reaction when involving no hydrogen [11]. It was concluded that carbon monoxide oxidation only required a small amount of cobalt oxide (around 15%); the excess cobalt formed bulk cobalt oxide which contributed little to the activity.…”

“…At present, Co catalysts have seldom been studied in the PROX reaction, and the Co 3 O 4 -CeO 2 catalyst has not been investigated for the preferential oxidation of carbon monoxide in gases highly rich in hydrogen, while this catalyst exhibits high activity in the CO oxidation reaction as the feeding gas of which doesn't contain H 2 [11,12]. In this work, a series of Co 3 O 4 -CeO 2 catalysts prepared by co-precipitation has been examined for CO oxidation in H 2 -rich gases.…”

Analysis and experimental investigation for collimator reflective mirror surface deformation adjustment

“…Collimator design is essential to satisfy the requirements of high-precision, large-aperture telescopes. The collimator diameter should be larger than that of the target for alignment without affecting the measurement results (Yang et al 2005). Mirrors with larger apertures will increase the surface deformation and stress, resulting in image quality degradation.…”