ABSTRACTS OF TECHNICAL ARTICLES 509 



time i)attein of the formaiit structure oocuiriug in ordinary speech. Tliere 

 is no a prion method of deteiinining how many l)uil(hn<>; l)locl<s are recjuired 

 to i)ro(hice inteUif^ihle stanihircHzed speech. This can only l)e determined 

 from experiments involving Ustening tests. Such tests are described. 



HOLDAWAY, Y. L.l 



Bulb Puncture in Gas Tubes, Electronics, 26, pp. 208, 210, 212, Nov., 

 1953. 



Hopkins, I. L.^ 



Ferry Reduction and the Activation Energy for Viscous Flow, J. 

 Appl. Phys., 24, pp. 1300-1304, Oct., 1953. 



The relationship proposed by Ferry and his co-workers for the effects of 

 frequenc}- and temperature on the dj-namic properties of certain jjolj-mers 

 is shown to lead to a method for calculating the activation energy of viscous 

 flow from relaxation, creep, and dynamic test data, the results agreeing with 

 those obtained in steach'-state flow. The Ferry reduction explains, and is 

 sui)ported by, observed increases in d}'namic modulus and viscosity with 

 increasing temperature. 



Jones, T. A.,i and W. A. Phelps.i 



A Level Compensator for Telephotograph Systems, A.I.E.E. Trans. 

 Commun. and Electronics, 9, pp. 537-541, Nov., 1953. 



Karnaugh, M.^ 



Map Method for Synthesis of Combinational Logic Circuits, A.I.E.E. 



Trans., Commun. and Electronics, 9, pp. 593-598, disc. pp. 598-599, 

 Nov., 1953. 



KoMPFNER, R.,1 and N. T. Williams.^ 

 Backward-Wave Tubes, I.R.E., Proc, 41, pp. 1602-1611, Nov., 1953. 



It has been surmised for some time that a ti-aveling-wave tube in which 

 backward-traveling field components can be excited — such as for in- 

 stance the "^lillman" tube — may oscillate in a Ijackward mode, the RF 

 power emerging at the gun-end of the tube and its frefjuency depending 

 only on the beam voltage. Experiments with the "Millman" tube show this 

 to be so and oscillations ha\-e been observed in the first and second back- 

 ward spatial-harmonic modes. The latter is excited between 600 and 900 

 volts, the tube oscillating between .5.9 and 6.4 mm. The foimer more power- 



' Bell Telephone Laboratories, Inc. 



