Abstract: A cryotrap for an air pollution analyzer having a core with an axial opening for receiving a cooling gas expander, a length of tubing carried on the core defining a gas flow path around the gas expander, and an electric heater on the core, with the tubing disposed between the heater and expander. The core has a helical groove around the exterior thereof, with the length of tubing positioned in the groove, and the heater positioned around the core over the tubing. A Stirling linear drive cooler charged with helium and having a gas compressor connected to one end of the gas expander with the other end of the expander positioned in the axial opening of the core.

Abstract: A system for remote measurement of wind velocity in the atmosphere, operating from ground level. An array of acoustic transducer elements which provide for transmitting a beam of acoustic energy along a path and receiving such transmitted energy as scattered by wind in the path. The system includes signal transmitting means for driving the arrays, and signal receiving means, with a switching system for connecting the elements of the array to the transmitting means and to the receiving means, for operation as a monostatic system. Phase control for the transmitted signals comprising phase shifters and switches for selectively connecting driving signals to the elements of the array for driving selected elements at different phases to produce first, second and third beams in sequence at three different predetermined angles from a single antenna.