 563  505. The transmission paths use the well-established principle of a common amplifier for both directions of transmission, the amplifier and the directional filters necessary for separating the two directional bands being connected in a figure-of-eight configuration with the amplifier in the common cross-over path. 506. Thus, the extent of operation of the hexosemono-phosphate oxidative pathway in a tissue might depend upon the presence in that tissue of a mechanism for oxidation of TPNH. This is borne out by the experiments of Hers demonstrating that glucose utilization by rat liver slices via the hexosemonophos-phate oxidative pathway can be increased by addition of substrates (glucosone and glucuronolactone) that oxidize TPNH, thereby making TPN available. Fatty acid synthesis can also be considered a mechanism for regenerating TPN from TPNH. 507. As we have seen, it is the exception rather than the rule for a human machine operator to feed input data or instructions directly into the machine. The rule is to have the input encoded on one of the automatic media and then read into the machine automatically and rapidly. The preparation of the automatic input medium (tape or cards) may be accomplished by an operator, or by means of another automatically fed machine; in the latter case the input to this machine has to be prepared, manually or automatically and so on. 508. Since the added contact is in parallel with the distributor points, the buzzer can have no effect when the distributor points are closed, even though it operates continuously. When the distributor points are open, however, the buzzer provides the electronic system with a series of firing signals in addition to the one provided by the distributor points. One of them is certain to fire the mixture on each compression, and quick starting is assured. 509. Such so-called midcourse manoeuvres are applied by means of a small rocket motor mounted in the spacecraft. The magnitude and direction of the correcting impulse are computed on the ground from radio measurements and, prior to the manoeuvre, the appropriate commands are sent by radio to the probe. In addition to presenting the theoretical foundations this paper gives representative figures for the errors both in determining the orbit and in applying the correction. Reference is also made to tracking sites and the mechanization in the spacecraft. 510. Commercially available tubes reach only to the vicinity of 4 mm. (75 KMC). Megavolt electronics and other new schemes are being investigated as millimeter wave generators. However, none of these has as yet produced a practical coherent CW oscillator. It was, therefore, necessary to look to harmonic generation for the microwave signal required for the development and testing of components in the 2 mm wavelength region. 563 |
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