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1181. Problems of gas kinetics in systems with adsorbing walls
Classified abstracts 1180-1322 C l a s s i f i e d a b s t r a c t s - - on t h i s page 1180-1189
Editor's note
The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
14:20 Gas flow in vacuum systems with local temperature variations for the molecular flow range. See abstract number 1238. 14 1180. Kinetic-theory deviations from Blanc's law of ion mobilities. (USA) Ion mobilities in gas mixtures are investigated by rigorous kinetic theory. It is shown that the Einstein relation between mobility and diffusion coefficient is exact in higher approximation and an explicit expression for the deviations from Blanc's law for ions in a binary gas mixture is obtained in second Chapman-Enskog approximation. Numerical calculations show that deviations from Blanc's law are usually small but that systems with large deviations are possible. S I Sandier and E A Mason, J Chem Phys, 48 (7), 1st April 1968, 2873-2875.
spectrometer analysis of the desorbed gases. The energy of activation, of the chemisorption was 0.4 eV and the adsorption temperature 3.4 eV. During the bombardment, CO, CO~ and O + are desorbed with an average energy of about 7 eV for O +. M I Datsiev and Yu I Belyakov, Zh Tekh Fiz, 38 (4), April 1968, 742-750 (in Russian). 16 1185. Method of determining the metal vapour condensation coefficient. (USSR) A new method for measuring the accommodation coefficient is described. The investigated metal is located in a sealed quartz ampoule inside evacuated bellows. After beating the system to a suitable temperature the ampoule is broken and vapours pass through an orifice in the temperature shields on the collector. The accommodation coefficient is determined by weighing. Using this method, the accommodation coefficient of Pb on Ni was found to be 1.0 in the temperature range of 200 to +400°C and 0.6 at +460°C. The accuracy of the method is within 10 per cent. V V Kantsel et al, Zh Tekh Fiz, 38 (4), April 1968, 751-756 (in Russian).
16. GASES AND SOLIDS
18. GASEOUS ELECTRONICS
I. General v a c u u m s c i e n c e and e n g i n e e r i n g 14. KINETIC THEORY OF GASES
16 : 37 Definition of surface: properties of metallic surfaces prepared under ultrahigh vacuum. See abstract number 1314. 16:47 1181. Problems of gas kinetics in systems with adsorbing walls. (Great Britain) A mathematical model is proposed for the description of molecular motions in a high vacuum system with adsorbing walls. The fundamental quantities, ie sorbing and outgassing characteristics, geometrical co-ordination between surface elements, and the position of a point internal to the system with respect to the surfaces, are all represented by matrices and vectors. The molecular trajectories are expressed in terms of operations on such matrices and vectors. In particular two expressions are derived, the first giving the rate of sorption of molecules on the surface, the second giving the density to be expected at a given location for a given gas load. C Pisani, Vacuum, 18 (6), June 1968, 327-334 16 : 18 1182. Field emission patterns from single crystal tungsten in the case of hydrogen adsorption. (USSR) Field emission from a single crystal tungsten tip was investigated in an electron microscope with the residual atmosphere analyzed by an omegatron. Measurements were performed at 5 × 10-9 torr on a mixture containing hydrogen, carbon monoxide and carbon dioxide. It was found that the adsorbed hydrogen has a strong influence on the emission patterns. A P Komar et al, Dokl Akad Nauk SSSR, 179 (3), 21st March 1968, 568-570 (in Russian). 16 1183. Measurement of the enthalpy of formation of barium hydride. (USSR) The quantity of heat released during formation of BaHa by direct reaction between Ba and Ha at 25°C was measured as 44.85 kcal/mol and the enthalpy determined to be --45.44 kcal/mol. A F Vorobev et al, Dokl Akad Nauk SSSR, 179 (5), llth April 1968, 1129-1132 (in Russian). 16 1184. Investigation of oxygen chemisurption on graphite using the slow electron desorption method. (USSR) Kinetics of desorption of chemisorbed oxygen on graphite, under bombardment by slow electrons, were investigated with mass
18 : 16 Field emission patterns from single crystal tungsten in the case of hydrogen adsorption. See abstract number 1182. 18 1186. Ignition of discharge gaps by a plasma jet. (USSR) The formation of a plasma in a high vacuum discharge initiated by the inlet of fast gas pulses was observed at different voltages of both polarities and different initiating plasma densities. E A Azizov and V S Komel'kov, Zh Tekh Fiz, 38 (4), April 1968, 628-636 (in Russian). 18 1187. Influence of anode orientation on the characteristics of a low pressure discharge in transversal magnetic field. (USSR) The influence of the angle between the anode axis and magnetic field vector on the discharge parameters was investigated for an inverse magnetron with a voltage of 1 to 6 kV and magnetic field of 250 to 2000 Oe in argon at a pressure of 5 × 10-5 to 5 × 10-4 tort. The discharge properties are described by one parameter stated in the article. At one determined angle not equal to zero the anode electron layer is doubled and the discharge current and the electron energies reach their maximal values with minimal electron current to the cathodes. N A Kervalishvili, Zh Tekh Fiz, 38 (4), April 1968, 637-645 (in
Russian). 18 1188. On the influence of strata on the electron energy distribution in a mercury-krypton mixture. (USSR) Correlation was found between the electron energy distribution character and strata oscillations of a discharge plasma in mixture of Hg at 10-8 tort and Kr at 10 3 to 4 torr. Deviations from the Maxwell distribution were also observed. E P Ostapehenko et al, Zh Tekh Fiz, 38 (4), April 1968, 661-662
(in Russian). 18:33 1189. Investigation of electron cooling of thermionic converter cathodes. (USSR) Electron cooling of the cathode of a thermionic converter with caesium vapour was investigated in the temperature range 1400 to 1800°C and the value of 18 to 10 grad.cm~/A was obtained. F V Kondrat'ev et al, Zh Tekh Fiz, 38 (4), April 1968, 704-708 (in
Russian). 529
Editor's note
The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
14:20 Gas flow in vacuum systems with local temperature variations for the molecular flow range. See abstract number 1238. 14 1180. Kinetic-theory deviations from Blanc's law of ion mobilities. (USA) Ion mobilities in gas mixtures are investigated by rigorous kinetic theory. It is shown that the Einstein relation between mobility and diffusion coefficient is exact in higher approximation and an explicit expression for the deviations from Blanc's law for ions in a binary gas mixture is obtained in second Chapman-Enskog approximation. Numerical calculations show that deviations from Blanc's law are usually small but that systems with large deviations are possible. S I Sandier and E A Mason, J Chem Phys, 48 (7), 1st April 1968, 2873-2875.
spectrometer analysis of the desorbed gases. The energy of activation, of the chemisorption was 0.4 eV and the adsorption temperature 3.4 eV. During the bombardment, CO, CO~ and O + are desorbed with an average energy of about 7 eV for O +. M I Datsiev and Yu I Belyakov, Zh Tekh Fiz, 38 (4), April 1968, 742-750 (in Russian). 16 1185. Method of determining the metal vapour condensation coefficient. (USSR) A new method for measuring the accommodation coefficient is described. The investigated metal is located in a sealed quartz ampoule inside evacuated bellows. After beating the system to a suitable temperature the ampoule is broken and vapours pass through an orifice in the temperature shields on the collector. The accommodation coefficient is determined by weighing. Using this method, the accommodation coefficient of Pb on Ni was found to be 1.0 in the temperature range of 200 to +400°C and 0.6 at +460°C. The accuracy of the method is within 10 per cent. V V Kantsel et al, Zh Tekh Fiz, 38 (4), April 1968, 751-756 (in Russian).
16. GASES AND SOLIDS
18. GASEOUS ELECTRONICS
I. General v a c u u m s c i e n c e and e n g i n e e r i n g 14. KINETIC THEORY OF GASES
16 : 37 Definition of surface: properties of metallic surfaces prepared under ultrahigh vacuum. See abstract number 1314. 16:47 1181. Problems of gas kinetics in systems with adsorbing walls. (Great Britain) A mathematical model is proposed for the description of molecular motions in a high vacuum system with adsorbing walls. The fundamental quantities, ie sorbing and outgassing characteristics, geometrical co-ordination between surface elements, and the position of a point internal to the system with respect to the surfaces, are all represented by matrices and vectors. The molecular trajectories are expressed in terms of operations on such matrices and vectors. In particular two expressions are derived, the first giving the rate of sorption of molecules on the surface, the second giving the density to be expected at a given location for a given gas load. C Pisani, Vacuum, 18 (6), June 1968, 327-334 16 : 18 1182. Field emission patterns from single crystal tungsten in the case of hydrogen adsorption. (USSR) Field emission from a single crystal tungsten tip was investigated in an electron microscope with the residual atmosphere analyzed by an omegatron. Measurements were performed at 5 × 10-9 torr on a mixture containing hydrogen, carbon monoxide and carbon dioxide. It was found that the adsorbed hydrogen has a strong influence on the emission patterns. A P Komar et al, Dokl Akad Nauk SSSR, 179 (3), 21st March 1968, 568-570 (in Russian). 16 1183. Measurement of the enthalpy of formation of barium hydride. (USSR) The quantity of heat released during formation of BaHa by direct reaction between Ba and Ha at 25°C was measured as 44.85 kcal/mol and the enthalpy determined to be --45.44 kcal/mol. A F Vorobev et al, Dokl Akad Nauk SSSR, 179 (5), llth April 1968, 1129-1132 (in Russian). 16 1184. Investigation of oxygen chemisurption on graphite using the slow electron desorption method. (USSR) Kinetics of desorption of chemisorbed oxygen on graphite, under bombardment by slow electrons, were investigated with mass
18 : 16 Field emission patterns from single crystal tungsten in the case of hydrogen adsorption. See abstract number 1182. 18 1186. Ignition of discharge gaps by a plasma jet. (USSR) The formation of a plasma in a high vacuum discharge initiated by the inlet of fast gas pulses was observed at different voltages of both polarities and different initiating plasma densities. E A Azizov and V S Komel'kov, Zh Tekh Fiz, 38 (4), April 1968, 628-636 (in Russian). 18 1187. Influence of anode orientation on the characteristics of a low pressure discharge in transversal magnetic field. (USSR) The influence of the angle between the anode axis and magnetic field vector on the discharge parameters was investigated for an inverse magnetron with a voltage of 1 to 6 kV and magnetic field of 250 to 2000 Oe in argon at a pressure of 5 × 10-5 to 5 × 10-4 tort. The discharge properties are described by one parameter stated in the article. At one determined angle not equal to zero the anode electron layer is doubled and the discharge current and the electron energies reach their maximal values with minimal electron current to the cathodes. N A Kervalishvili, Zh Tekh Fiz, 38 (4), April 1968, 637-645 (in
Russian). 18 1188. On the influence of strata on the electron energy distribution in a mercury-krypton mixture. (USSR) Correlation was found between the electron energy distribution character and strata oscillations of a discharge plasma in mixture of Hg at 10-8 tort and Kr at 10 3 to 4 torr. Deviations from the Maxwell distribution were also observed. E P Ostapehenko et al, Zh Tekh Fiz, 38 (4), April 1968, 661-662
(in Russian). 18:33 1189. Investigation of electron cooling of thermionic converter cathodes. (USSR) Electron cooling of the cathode of a thermionic converter with caesium vapour was investigated in the temperature range 1400 to 1800°C and the value of 18 to 10 grad.cm~/A was obtained. F V Kondrat'ev et al, Zh Tekh Fiz, 38 (4), April 1968, 704-708 (in
Russian). 529