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The interaction of oxygen with clean lead telluride surfaces
Classified
abstracts
18764973
Classified abstracts 18764889 on this page
Editor’s Note The label immediately following fhe title of each item denotes country or origin of publicafion, and that af the end of each abstract indicates country of origin of work (where known).
I. General vacuum
science
and engineering
15. Fluid dynamics
15 1876. Approxhnate calculation of expansion of w from nozzles into high VBCUUIII.(USA) The exact calculation of the density of a steady state gas flow by means of the Boltzmann function generally leads to great mathematical difficulties in the case of an expanding gas passing from the viscous flow region into the molecular flow region. An approximate solution is found by replacing the actually continuous transition from viscous to molecular flow with a suitably defined discontinuity surface. H G Niiller, J Vat Sci Technol, 3 (4), 1966,202-207. 15 1877. Quick measurements of dynamic pressures in gas streams. (France) A short response time transducer consists of a Mylar membrane on which are disposed, on either side, thin film strips of Bi in a bridge form, separating two cavities communicating to the exterior pressure connections with hypodermic needles. The sensitivity can be varied by changing the Mylar thickness. P Vafentin et al, Rev Hautes Temp Refractaires, 2 (4), 1965, 293 (in French). 15 1878. A Mont+Carlo computer programme for analysis of molecular gas Bow. (Great Britain) Molecular gas flows cannot be studied analytically within vacuum systems in which a pumping orifice or surface forms an appreciable fraction of the total internal surface area of the system. Such systems may be studied successfully by the Monte Carlo method in which an average picture of the molecular flow is by mathematical simulation of the course of a large. number of individual molecular histories within a mathematical representation of the vacuum system. J N Chubb, UKAEA CLM Report R-54,1965, 12pages. 16. Gases and solids 16 1879. Gas absorption in horixontal co-current bubble flow. (Canada) Co-current flow pipeline reactors would have several advantages for gas liquid reacting systems. The present study was made for the purpose of obtaining the first data on liquid phase controlled adsorption of gases on horizontal co-current two phase flow. D S Scott and W Hayduk, Can J Chem Eng, 44,1%6,130-136. 16 1880. Oxygen chemisorption on doped nickel oxide and related conductivity changes. (Great Britain) The chemisorption of 0, on NiO doped with Li, and Cr,O, has been studied in the temperature range 250-350°C. The uptake and the dc conductivity changes occurring during the adsorption were measured simultaneously and recorded continuously. Pressure changes were followed in a constant volume apparatus by a self-balancing Pirani gauge and the conductivity changes were determined using a novel electrode assembly. P G Dickens and T K Halstead, Trans Faraday Sot, 62, 1966, 1620-1631. 16 1881. Increasing adsorption rates by means of pulsations. Part 4. (Roumania) The adsorption of CO* in wetted-wall cohmms was studied and the results obtained were compared with earlier results obtained in this series, in order to present some conclusions concerning the mechanism
of rate increase of the adsorption by pulsation of the gas phase. R Z Tudose, Bul Inst Politeh Iasi, II, 1965,143-150 (in Roumanian). 16 1882. Calculation of diffusion coetlicients of bii gas mixtures. (India) Investigates the relative applicability of the semi-empirical methods for calculating the values of binary diffusion coefficients for a large number of binary gas mixtures at high temperatures. M P Sakssena and S C Saxena, Indian J Pure Appl Phys, 4 (3), 1966, 109. 16 1883. Physisorption of Xe and Kr on &ss and molybdenum films. (USA) Physisorption of room temperature Xe and Kr at low pressures (1&*-10’4 torr) on Pyrex, and on molybdenum films at 77” and 87°K has been investigated. The initial sticking nrobabilities are close to unity and theabsorbate shows high surfa-ce mobility. The steady-state data, which can be shown to differ little from equilibrium data fit the Polyani potential theory and the Dubinin-Radushkevich isotherm. N Endow and R A Pastemak, J Vat Sci Technol, 3, 1966, 196-201. 16 1884. A new method for prediction of binary gas-phase diiTusion coetBcients. (USA) An easily applied method for predicting binary gas-phase diffusivities is based on the use of special diffusion volume coupled with extensive experiment and nonlinear least-square analysis of the data. E N Fuiler et al, Znd Eng Chem, 58,1966,18-27. 16 1885. Apparatus for gas separation by diffusion. (Germany) The tube-formed membranes of a gas separation diffusion apparatus are arranged like tubes of a heat exchanger for their protection and to keep them under uniform tension. Y Dnrlau et al, German Patent 1,213,384 (C1.B Old), 31 March 1966, French Appl3 May 1957, 7 pages. 16 1886. A study of stepwise adsorption. (USA) Isotherms are reported for adsorption of CZH6Cl, CHC&, CFC&, and C,H, on a uniform graphite surface. At low reduced temperatures (P,, is less than 5 torr) all except benzene have a vertical phase change in the submonolayer region of the isotherm and a sharp second layer step both due to lateral interactions. B W Davis and C Pierce, J Phys Chem, 70, 1966, 1051. 16 1887. The adsorption of wwious gases on clean and oxidixcd germanium surfaces. (Netherlands) Some adsorption experiments were carried out on germanium surfaces. The Ge crystal was crushed in vacuum and heated in high vacuum. Significant differences were found in the adsorption of HCl, H,S and NH, on clean Ge surfaces. A H Boon&a and J Van Ruler, Surface Sci, 4, 1966, 141-149. 16 1888. The interaction of oxygen with clean lead telbuide surfaces. (f-A) The kinetics of oxygen adsorption on lead tellmide surfaces, produced by crushing in vacua have been investigated in the temnerature range 195-303°K: M Green and M J Lee, J Phys Chem Solidr, 27,1966, 797-804. 16 1889. A simple apparatus for adsorption studies. (India) A simple apparatus is described for conducting adsorption studies at different vapour pressures. The apparatus consists of an adsorption 551
abstracts
18764973
Classified abstracts 18764889 on this page
Editor’s Note The label immediately following fhe title of each item denotes country or origin of publicafion, and that af the end of each abstract indicates country of origin of work (where known).
I. General vacuum
science
and engineering
15. Fluid dynamics
15 1876. Approxhnate calculation of expansion of w from nozzles into high VBCUUIII.(USA) The exact calculation of the density of a steady state gas flow by means of the Boltzmann function generally leads to great mathematical difficulties in the case of an expanding gas passing from the viscous flow region into the molecular flow region. An approximate solution is found by replacing the actually continuous transition from viscous to molecular flow with a suitably defined discontinuity surface. H G Niiller, J Vat Sci Technol, 3 (4), 1966,202-207. 15 1877. Quick measurements of dynamic pressures in gas streams. (France) A short response time transducer consists of a Mylar membrane on which are disposed, on either side, thin film strips of Bi in a bridge form, separating two cavities communicating to the exterior pressure connections with hypodermic needles. The sensitivity can be varied by changing the Mylar thickness. P Vafentin et al, Rev Hautes Temp Refractaires, 2 (4), 1965, 293 (in French). 15 1878. A Mont+Carlo computer programme for analysis of molecular gas Bow. (Great Britain) Molecular gas flows cannot be studied analytically within vacuum systems in which a pumping orifice or surface forms an appreciable fraction of the total internal surface area of the system. Such systems may be studied successfully by the Monte Carlo method in which an average picture of the molecular flow is by mathematical simulation of the course of a large. number of individual molecular histories within a mathematical representation of the vacuum system. J N Chubb, UKAEA CLM Report R-54,1965, 12pages. 16. Gases and solids 16 1879. Gas absorption in horixontal co-current bubble flow. (Canada) Co-current flow pipeline reactors would have several advantages for gas liquid reacting systems. The present study was made for the purpose of obtaining the first data on liquid phase controlled adsorption of gases on horizontal co-current two phase flow. D S Scott and W Hayduk, Can J Chem Eng, 44,1%6,130-136. 16 1880. Oxygen chemisorption on doped nickel oxide and related conductivity changes. (Great Britain) The chemisorption of 0, on NiO doped with Li, and Cr,O, has been studied in the temperature range 250-350°C. The uptake and the dc conductivity changes occurring during the adsorption were measured simultaneously and recorded continuously. Pressure changes were followed in a constant volume apparatus by a self-balancing Pirani gauge and the conductivity changes were determined using a novel electrode assembly. P G Dickens and T K Halstead, Trans Faraday Sot, 62, 1966, 1620-1631. 16 1881. Increasing adsorption rates by means of pulsations. Part 4. (Roumania) The adsorption of CO* in wetted-wall cohmms was studied and the results obtained were compared with earlier results obtained in this series, in order to present some conclusions concerning the mechanism
of rate increase of the adsorption by pulsation of the gas phase. R Z Tudose, Bul Inst Politeh Iasi, II, 1965,143-150 (in Roumanian). 16 1882. Calculation of diffusion coetlicients of bii gas mixtures. (India) Investigates the relative applicability of the semi-empirical methods for calculating the values of binary diffusion coefficients for a large number of binary gas mixtures at high temperatures. M P Sakssena and S C Saxena, Indian J Pure Appl Phys, 4 (3), 1966, 109. 16 1883. Physisorption of Xe and Kr on &ss and molybdenum films. (USA) Physisorption of room temperature Xe and Kr at low pressures (1&*-10’4 torr) on Pyrex, and on molybdenum films at 77” and 87°K has been investigated. The initial sticking nrobabilities are close to unity and theabsorbate shows high surfa-ce mobility. The steady-state data, which can be shown to differ little from equilibrium data fit the Polyani potential theory and the Dubinin-Radushkevich isotherm. N Endow and R A Pastemak, J Vat Sci Technol, 3, 1966, 196-201. 16 1884. A new method for prediction of binary gas-phase diiTusion coetBcients. (USA) An easily applied method for predicting binary gas-phase diffusivities is based on the use of special diffusion volume coupled with extensive experiment and nonlinear least-square analysis of the data. E N Fuiler et al, Znd Eng Chem, 58,1966,18-27. 16 1885. Apparatus for gas separation by diffusion. (Germany) The tube-formed membranes of a gas separation diffusion apparatus are arranged like tubes of a heat exchanger for their protection and to keep them under uniform tension. Y Dnrlau et al, German Patent 1,213,384 (C1.B Old), 31 March 1966, French Appl3 May 1957, 7 pages. 16 1886. A study of stepwise adsorption. (USA) Isotherms are reported for adsorption of CZH6Cl, CHC&, CFC&, and C,H, on a uniform graphite surface. At low reduced temperatures (P,, is less than 5 torr) all except benzene have a vertical phase change in the submonolayer region of the isotherm and a sharp second layer step both due to lateral interactions. B W Davis and C Pierce, J Phys Chem, 70, 1966, 1051. 16 1887. The adsorption of wwious gases on clean and oxidixcd germanium surfaces. (Netherlands) Some adsorption experiments were carried out on germanium surfaces. The Ge crystal was crushed in vacuum and heated in high vacuum. Significant differences were found in the adsorption of HCl, H,S and NH, on clean Ge surfaces. A H Boon&a and J Van Ruler, Surface Sci, 4, 1966, 141-149. 16 1888. The interaction of oxygen with clean lead telbuide surfaces. (f-A) The kinetics of oxygen adsorption on lead tellmide surfaces, produced by crushing in vacua have been investigated in the temnerature range 195-303°K: M Green and M J Lee, J Phys Chem Solidr, 27,1966, 797-804. 16 1889. A simple apparatus for adsorption studies. (India) A simple apparatus is described for conducting adsorption studies at different vapour pressures. The apparatus consists of an adsorption 551