1587.
1568.
30
(c) Photographic micro-flash equipment capable of giving a Aash of 1/200,000 second or shorter duration, at a minimum recurrence frequency of 200 flashes per second;
(d) Photographic systems spocially designed for use in space
vchicles:
(e) Streak cameras having writing speeds of 8 millimetres) microsecond and above capable of recording events which are not initiated by the camera mechanismo.
Quartz crystals and assemblies thereof in any stage of fabrica- tion (ie. worked, semi-finished or mounted), as follows--
(a) For use as filters-
(i) specially designed crystals; or
(ii) assemblies of crystals;
(b) For use as oscillators-
(i) designed for operation over a Lemperature range wider than 70°C;
(ii) designed for a frequency stability of plus or minus 0.003% or better over the rated temperature range:
(ii) mounted in glasa holders;
(v) mounted in metal holders sealed with thermocom- pression welding: or
(v) capable, when mounted, of being passed through a circular hole with a diameter of 0.42 inches (10.7 milli- metres).
Materials composed of crystals having spinel, hexagonal pr garnet crystal structures. thin film devices; assemblies of the foregoing; and devices containing them, not elsewhere specifled, as follow-
(4) Monocrystals of ferrites and garnets, synthetic only;
(+) Single aperture forms possessing any of the following
characteristics-
(0) Switching speed of 0.5 microsecond or less at the minimum field strength required for switching at 40°C;
(i) A maximum dimension less than 45 mils (1.14 millimetres);
(c) Multi-aperture forms with fewer than 10 apertures pos-
sessing any of the following characteristics
(1) Switching speed of 1 microsecond or less at the minimum field strength required for switching at 40°C.;
(ii) A maximum dimension less than 100 mila (2.54 millimetres);
(4) Multi-aperture forms having 10 or more apertures; (e) This film memory storage or switching devices;
(f) Electrical filters in which the coupling clement makes use
of the electromechanical properties of ferrites;
(g) Materials suitable for application in clectromagnetic devices
making use of the gyro-magnetic resonance phenomenon.
1993.
1595.
31
Measuring, calibrating, counting, and time interval measuring equipment, whether or not incorporating frequency standards, having one or more of the following characlecistics-
(a) (0) Consisting of, or containing. frequency measuring equipment or frequency standards designed for other than ground laboratory use with an accuracy better than I part in 107:
(Ü) Consisting of, or containing, ground laboratory frequency standards or frequency measuring equipment incorporating frequency standards with a stability over 24 hours of 1 part in 10% or better;
(b) Designed for use at frequencies in excess of 1,000 mega-
cycles per second;
(c) Designed to provide a multiplicity of alternative output frequencies controlled by a lesser number of piezo-electric crystals or by an internal or extemal frequency standard except equipment in which the output frequency is selected only by manual operation either on the equipment or on a remote control unit and
() those forming multiples of frequency; or
EL
common control
(f) those in which the output frequency is a multiple of a common frequency which is not less than 1/1,000th part of the oscillator frequency and is in steps of 1 kilocycle per second or greater;
(d) Counting equipment capable of resolving al normal impul levels successive input signals with less than 0.1 microsecond Lime difference;
(e) Timo interval measuring equipment containing counting
equipment as specified in sub-item (d).
Gravity meters (gravimeters) and specialized parts therefor designed or modified for airborne or marine use.
GROUP H.
METAL, MINERALS AND THEIR MANUFACTURES.
In this Group--
Raw materials covers all materials from which the metal can be usefully extracted, fe orea, concentrates, matte, regulus, residues and dross (ashes); and
Unless provision to the contrary is made in particular items of the definition. the words metal and alloys cover all crude and semi-fabricated forms as follows-
Crude forms:
Anodes, balls, bars (including notched bars and wire bars), billets, blocks, blooms, brickets, cakes, cathodes, crystals, cubes, dice, grains, granules, ingots, humps, pellets, pigs, powder, rondelles, shot, slabs, slugs, sponge, sticks