Abstract: This invention relates to a pulsed power amplifier 100 for amplifying radio frequency signals. The pulsed power amplifier comprises control means 124, 126, 102 for generating control signals to control the amplifier output power so as to provide an output power pulse having rising and falling transitional phases, and means 112, 114, 117, 118, 122, 132, 134, 137, 138, 142 for generating a subsidiary pulse signal to be applied to the control means in order to adjust a transitional phase of the output power pulse. The generation of the subsidiary pulse may depend on a measured parameter of a previous output power pulse, such as the time taken for a preceding output power pulse to reach a predetermined output power level. Alternatively, the generation of the subsidiary pulse may depend on a parameter of the present output power pulse. In both cases the generating means can control the magnitude of the subsidiary pulse in response to the parameter.

Abstract: Herbicidally active substituted phenyl carbamates I ##STR1## in which R.sup.1 represents a C.sub.1 -C.sub.6 alkyl group, a C.sub.3 -C.sub.6 cycloalkyl group or an aryl group, which aryl group may be substituted by a halogen atom and/or a C.sub.1 -C.sub.6 alkyl group and/or a trifluoromethyl group, and R.sup.2 represents a C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl or C.sub.2 -C.sub.6 alkynyl group that may be substituted by a terminal halogen atom, are prepared by reacting N-hydroxyphenyl carbamates II ##STR2## with either isocyanates R.sup.1 --N.dbd.C.dbd.O or amino chlorides R.sup.1 --NH--COCl in an aqueous medium thus avoiding the use of organic solvents. The end product I may be extracted from the aqueous slurry into a water-immiscible solvent.The N-hydroxyphenyl carbamates II can be prepared by reacting 3-aminophenol with chloroformates in an aqueous medium, and the resulting product may be reacted in situ, without isolation, with isocyanates, in the same reaction vessel.

Abstract: A tobacco or similar packing of the folding bag type, i.e. comprising a strip of sheet material which is folded about a transverse folding line offset from the middle of the strip so as to present a front panel having a free top edge and a bottom edge constituted by said folding line, and a rear panel extending upwardly from said bottom edge to beyond the top edge of the front panel, the side edges of the adjacent panels being joined so as to define a flat bag portion, the rear side of which is extended into a flap portion beyond the top of the bag portion, said flap portion being folded or adapted to be folded down along the front side of the bag together with the uppermost part of the bag portion, about a second transverse folding line underneath the top edge of the front panel, and being fastened or adapted to be fastened in a releasable manner to the exterior surface of said bag portion by means of adhering fastening means.