ABSTRACT
A plasma jet produced in a small coaxial plasma gun operated at voltages up to 2 kV and working in pure carbon dioxide (CO2) at a few Torr is used to remove Martian soil simulant from a surface. A capacitor with 0.5 mF is charged up from a high voltage source and supplies the power to the coaxial electrodes. The muzzle of the coaxial plasma gun is placed at a few millimeters near the dusty surface and the jet is fired parallel with the surface. Removal of dust is imaged in real time with a high speed camera. Mars regolith simulant JSC-Mars-1A with particle sizes up to 5 mm is used on different types of surfaces made of aluminium, cotton fabric, polyethylene, cardboard, and phenolic.
ABSTRACT
A pulsed electron beam accelerated at 12 kV with a duration of 40 µs per pulse is obtained from a Penning discharge with a hollow anode and two cathodes. The electrons are extracted through a hole in one of the cathodes and focused by a pair of coils. The electron beam has a diameter of a few mm in the cross section, while the beam current reaches peak values of 400 mA, depending on the magnetic field inside the focussing coils. This relatively inexpensive and compact device is suitable for the irradiation of small material samples placed in high vacuum.
ABSTRACT
Several substituted 2- and 4-hydroxyacetophenones are linked to Wang resin via a modified Mitsunobu protocol. These resin-bound acetophenones are condensed with aromatic aldehydes, and the resulting chalcones 5 are used for the synthesis of 2-dialkylamino- (9a-d) and 2-alkylamino-4,6-diarylpyridines (11a-f), and 2-alkyl-4,6-diaryl- (14a) and 2,4,6-triarylpyrimidines (14b,c) in a manner suitable for combinatorial applications.
