Papers by Keyword: Secondary

Abstract: Fast-steering Secondary Mirror (FSM) will be installed to the Giant Magellan Telescope (GMT) as a first generation secondary mirror. The FSM implements a tip-tilt mechanism which compensates image degradations caused by wind turbulence and structure jitter. A prototype segment of the FSM has been developed, which comprised of a dummy mirror, a mirror cell, axial and lateral supports, vacuum devices, etc. Several test-bed frames have been developed to hang the segment and to test tip-tilt functionalities. They have been designed, manufactured, assembled, and verified successfully step by step. Tip-tilt measurements were performed mainly by displacement measuring sensors which detect eddy currents precisely. The results proved that the prototype segment worked successfully, by complying the requirements of the FSM for the tip-tilt actuations.

Abstract: The presence of corrosion inhibitors in the composition of building materials is an innovative feature that significantly contributes to the prolongation of the life cycle of reinforced concrete and the rehabilitation procedure itself. Limited control and the high cost of modifying additives result in failure of prescribed dosage and thus limited function. The article describes the methodology for determining the presence of corrosion inhibitors based on amines through a colored reaction of amines with ninhydrin agent.

Abstract: Long primary double sided linear motor drive technology is applied in electromagnetic aircraft launch application. Due to the structure of the secondary board, there is a great room for the improvement of electromagnetic thrust for the long primary double sided linear motor. This paper studies mainly the secondary structures of the long primary double sided linear motor. The results of this paper lead to a better performance of the motor by the transformation of the structural design of the secondary board.

Abstract: A method for formation of enhanced ohmic contacts on SiC for operation under adverse conditions has been studied. Ni, NiSi2 and Si ohmic contacts were prepared and tested at 300°C on air for hundreds of hours. NiSi2 and Si showed high thermal stability. Moreover, also the so called secondary contacts showed preserved good electrical and structural properties in the thermal test. The secondary ohmic contacts are formed from original ohmic contacts after they are etched off and replaced with new ones. Secondary ohmic contacts originate in a certain surface modification of the SiC substrate created during high temperature annealing of the original contact. All applied contact materials enable formation of quality secondary contacts which is especially noteworthy at NiSi2 and Si. The results bring new SiC device design perspectives with the application of secondary ohmic contacts. For example, the contact is designed so that the primary contact makes as good ohmic behavior as possible with the secondary contact providing further important contact properties as high corrosion resistance, wire-bonding simplicity etc.