*
(e) Valves constructed with ceramic envelope:
( Valves designed for operation in ambient temperatores exceeding 100°C; (g) Amplifier Klýštrons;
(A) Travelling wave tubes,
29. Thyratron and modulator gas-discharge tubes, as follows:
(a) Those mated for continuous operation with peak current and peas voltage exceeding 100 amperes and 9.000 volis at a pulse repetitive frequency of 200 or more pulses per second;
(8) Hydrogen thyratrons of any rating.
(Note: The following is the definition of "thyrstroo":
Thyrotron!
Any hot cathode gas-filled tube containing 3 or mun electrodes in which anode current flow is initi by a control electrode).
30. Electronic components designed for and/or capable of reliable performans in relation to their electrical and mechanical characteristics and maintaining their design service lifetime while operating;
(a) Over the whole range of ambient temperatures extending from below
minus 45°C to above plus 100°C; or
(6) At ambient temperatures of 200°C or higher,
31. Materials designed and manufactured for use as absorbers of electro- magnetic waves having frequencies greater than 2 x 100 cycles per second, and less than 3 X 1012 cycles per second.
32. Tantalum electrolytic capacitors not elsewhere specified, as follows:
(a) All types designed to operate at temperatures exceeding 85°C; (b) Sintered electrolytic capaciton;
(c) Electrolytic capacitors constructed with foila,
13. Electronic computers (except business-type machines, accounting machine
and statistical calculating machines).
34. Equipmcat specially designed to produce clectronic assemblies;
(a) By depositing or printing on insulating panels (including plates and wafers) or otherwise forming in sing component parts other than basi: wiring, or
(6) By automatically inserting and/or soldering components on insulating panels (including plates and wafers), to which "wiring is applied by printing or other means.
35. All electronic control equipment.
36. Magnetometers of the following types:
(0) Fluxgate;
(6) Electron beam sensing;
(c) Paramagnetic;
(d) Nucleomicz
and specialized parts therefor.
37. Magnetic recorders and/or reproducers, other than those designed for moist or music, and specialized recording media and parts and components therefor.
38. Centrifugal testing apparatus or equipment possessing any of the following
characteristics:
(a) Driven by a motor or motors having a total rated horsepower greater
than 400 h.p.;
(5) Capable of carrying a payload of 250 lbs. or more;
(c) Capable of exerting a centrifugal acceleration of 8 or more “g” on a
payload of 200 lbs or more.
3. Ion microscopes having a resolving power better than 10 Angstrom units. #. Oscilloscopes (cathods ray) and specialized parts therefor.
4. Photographic equipment, as follows:
(a) High-speed cinema recording cameras comploying:
(1) Film widths 35 mm. or narrower and recording at rates exceeding 3,000 frames per secood in the case of equipment using as the lighting source a steady light flow and 10,000 frames per second in the case of equipment using as the lighting source flash equip- ment connected to the unwinding system;
(2) Film widths greater than 35 mm. and recording at rates exceeding
64 frames per second.
(6) Other high speed cameras capable of recording at rates in skocss of
250,000 frames per second:
(c) Photographic micro-flash equipment capable of giving a flash of 1/100,000 second or shorter" duration," at a minimum recurrence frequency of 200 flashes per second.
22 Quartz crystals (worked or unworked) and plates, radio grade only.
43. Measuring and counting equipment, as follows:
(2) Time interval measuring equipment with self-contained reference fre-
quency, having one or both of the following characteristics :
(1) Capable of measuring time intervals of 1/10 second or less with
an error not exceeding 1 micro-second plus 0.001 per cent of the interval measured;
(2) Incorporating counting circuits capable of counting at rates in
excess of 1 megacycle per second.
(b) Counting equipment capable of counting at rates in excess of 1
megacycle per second.
GROUP H.
METALS AND MINERAL MANUFACTURES.
I. Ball and roller bearings and parts therefor.
1. Magactic metals of all types and of whatever form, eg. powder, strip, sheet, casting, and blocks, if possessing one or more of the following characteristică:
(0) Grain oriented sheet or strip of a thickness of 0,2 mm, (0.008 inches)
or less
(M) Initial permeability 50,000 ar over;
(2) Remanence 98 per cent or over of maximum flux for materials having
magnetic permeability;
(d) A composition capable of an energy product greater than 6 times
106 gausses/persteds, or containing more than 25 per cent cobalt:
(e) Core loss of 1 watt per kg. (0.45 watts per pound) or lesa au B=13,000 gausscs and at 50 cycles per second (1.36 watts per kg. or 0.62 watts per pound at B≈15,000 gaustes and at 50 cycles per second) or less for grain oriented sheet and strip of a thickness of 0.31 mm, (0.012 inches) or less.
1. Permanent magnets of all types.
* Alloy steels containing 50 per cent or more iron and
e) (1) 10 per cent or more molybdenum (but 5 per cent or more molybdenum in any alloys containing more than 14 per cent chromium); or