Showing papers on "Buffer gas published in 1975"

Process for preparing finely-divided refractory powders

Abstract: Helical flow of hot plasma gas, e.g., hydrogen gas, produced by a gas vortex stabilized plasma arc is cancelled by introducing attenuating gas, e.g., hydrogen gas, into the hot plasma gas in a manner such that the attenuating gas assumes a vortical direction opposite to the helical flow of the hot plasma gas. The resulting gas stream is well-collimated. The well-collimated plasma gas stream is used in the preparation of finely-divided refractory metal and metalloid carbides, borides, nitrides, silicides and sulfides. Reactants for the preparation of the aforementioned refractory powders are introduced into the collimated plasma gas stream. The reaction is conducted in the gas phase within a reactor and solid, finely-divided refractory powder removed from the reactor.

Collision processes of drifting O+ and N+ ions

Abstract: Rate constants for charge transfer and interchange reactions of O+ and N+ ions with N2, O2, NO and CO have been measured in the injected ion drift tube, using helium as buffer gas. The range of mean impact energies is 0.04-2 eV. Agreement with previously reported data is, on the whole, good. Energy distributions of ions emerging from the drift tube have been measured using planar retarding grids, and the mean energies E are found to be in agreement with the expression E=1/2m+ nu d2+1/2mg nu d2+3/2kT for ion mass m+, buffer gas mass mg, and drift velocity nu d.

Inert atmosphere chamber

Abstract: An inert gas chamber for use in continuously curing oxygen sensitive coating compositions by the application of radiation, employs a jet of inert gas to displace the air boundary layer on the coated substrate as the coated substrate moves into the chamber. The coated substrate is also blanketed with inert gas and subjected to the radiation. The use of inert gas to cool the window of the electron beam accelerator may be used in the chamber, thus avoiding ozone-based pollution.

Pressure and Temperature Coefficients of the More Commonly Used Buffer Gases in Rubidium Vapor Frequency Standards

Abstract: The temperature and pressure coefficients of three buffer gases, N2, Ar, Kr, commonly used in passive Rb57 frequency standards have been accurately determined. Techniques for filling cells reproducibly, are described. From the results obtained, calculations are made on the expected characteristics of gas mixtures. Graphs are given which can be used to select the proper buffer gas mixture and pressure to obtain specially required frequency shift and temperature coefficient in a given cell.

A copper laser using CuI vapor

Abstract: A simple CuI double-pulsed laser was built. The dependence of power output on the delay between the two excitation pulses, temperature, and the type of buffer gas has been investigated. The laser pulse duration was measured.

Theory for time resolved emission spectra

Abstract: Explicit equations for the calculation of time resolved emission spectra from molecules undergoing collisional vibrational relaxation are presented. The equations describe the changes of the emission spectrum with time, after a delta pulse excitation. Alternatively, they can be used to obtain the steady state (frequency resolved) emission spectrum as a function of the pressure of added buffer gas. Some model cases are discussed in the light of available experimental data. Non-monotonic dependences of the emission intensity on time and pressure are exhibited which are related in appearance to those expected from quantum mechanical interference effects.

Product ion diffusion in flowing afterglows

Abstract: An analysis of the variation of product ion signals in flowing afterglow experiments is presented. It is shown that under certain conditions the relative variation of a single product ion yields not only the total reaction rate coefficient but also the ambipolar diffusion coefficient of the product ion in the buffer gas. Theory is compared with experiment for a number of ion-molecule and Penning reactions.

Dynamic effective diffusivsty when applied to the pressure increase during reaction for multicomponent gaseous systems within a porous solid

Abstract: α-Hematite powder of 8.1 μm in average diameter was packed in a quartz tube and was reduced by feeding pure hydrogen toward the upper surface of the packed bed at 900°C and the pressure increase within the bed was measured. Midway through the reduction, hydrogen-inert gas mixtures were fed instead of pure hydrogen and the variation of the pressure increase ΔP within the bed with increasing mole fraction of inert gas in feed gas, xI, 0, was investigated. Nitrogen, argon, and helium were used as the inert gas and it was found that the relationship between ΔP and xI, a varied with each inert gas. To interpret those phenomena, the concept of the multicomponent dynamic effective diffusivity is proposed. It will make the nonisobaric analysis of solid-multicomponent gas reactions possible.

Storage tank system for gas fuelled engines - has two stage cryogenic and buffer tank system

Abstract: A storage tank system for heat engines, partic. motor vehicle engines consists of a two-stage tank contg. a main tank filled with liquid gas e.g., H2 at cryogenic levels and a secondary buffer tank contg. gas at normal temp. but under pressure. Transfer of vaporising liquid gas from the cryogenic tank to the buffer tank is by automatic valves or a pump sytem. Metallic hydrides may also be used to produce a buffer gas pressure.

Electron-potassium spin-exchange cross section

Abstract: A spin-exchange optical-pumping experiment to measure the electron-potassium spin-exchange cross section in a He buffer gas is reported. Electrons are polarized by spin-exchange collisions with optically pumped K atoms. The value of the spin exchange cross section at thermal energy is measured to be (6.8+or-1)*10-14 cm2. The electron-spin resonance linewidths are measured over the temperature range 85-120 degrees C. They fit the theoretical temperature dependence Delta nu (T) varies as P(K)T-32/, indicating that the width of the free electron resonance is caused mainly by spin-exchange collisions.

Electric incandescent tungsten-bromine lamps prodn - by doping inert gas filling with bromoform and phosphine, sealing and heating

Abstract: Electric lamps with a W filament and an inert gas filling contg. Br2 and H2 and also P in a sealed envelope of refractory transparent material are producing by introducing inert gas doped with CHBr3 vapour and gaseous PH3 into the envelope, sealing this and decomposing the CHBr3 and PH3 into Br2, H2 and P by raising to the temp. occurring when the lamp is started. The inert gas pref. is doped with CHBr3 vapour at a partial pressure of 1-5, esp. 1.5-4 torr, while the PH3 partial pressure is 2-50, esp. 5-20 torr. The inert gas is pref. doped by passing through a thermostated reservoir contg. CHBr3 at 0-20 degrees C. The production of lamps of theW-Br2 type is simplified.

Process and apparatus for producing an inert gas

Abstract: Process for the production of an inert gas wherein liquid or gaseous hydrocarbons are burnt within a combustion chamber with air, possible with the admixture of a gaseous atomizing agent, especially steam, gas inert gas or air, whereby a first shock-like cooling is performed, which is followed by a second cooling step and a scrubbing with water or an aqueous solution of a temperature in the vicinity of the freezing point, and the gas treatment is finished with an adsorption drying. The invention relates also to an apparatus for carrying out such process.

Submillimeter wave and far infrared molecular lasers and polyatomic buffer gases therefor

Abstract: The optically pumped submillimeter wave lasers employing molecular gases having dipole moments are improved by employing as a polyatomic buffer gas a molecular gas or vapor of a hydrocarbon having a significantly large vibrational heat capacity in relation to its molecular weight. An example is C 6 H 14 added to such lasers as the methyl fluoride laser at 496 micrometers. Other examples of saturated hydrocarbon buffers are also given; and in each case the vapor molecule is complex enough to absorb many vibrational quanta from the active molecules, yet is small enough to move rapidly to the tube walls.

Gamma irradiation induced isotope exchange in nitrogen sensitized by helium, neon and argon

Abstract: Irradiated inert gases may transfer absorbed energy to nitrogen, resulting in the production of excited nitrogen molecules, ions and N atoms. These processes may promote nitriding of fast reactor components if the cover gas contains nitrogen impurity. This paper describes an investigation of energy transfer to nitrogen from helium, neon and argon. The efficiency of N atom formation was determined by 60Co gamma irradiation of rare gases containing 14N14N and 15N15N, with measurement of the product 14N15N by mass spectrometry. The results are correlated with the energy levels of the states produced on irradiation of the rare gases. Helium ions and metastable atoms are very efficient at producing N atoms by energy transfer to nitrogen. The helium ions have sufficient energy to produce N+, N+3 and excited N+2 ions, resulting in increased N atom formation. Neon ions and metastables give N+2 ions but not the higher ionic states. In the argon system, only Ar+ gives efficient production of N atoms. N atoms are not produced in low concentrations of nitrogen in argon. Sodium vapour caused no enhancement of N atom formation in argon, and it is concluded that N atoms would not be produced in a fast reactor cover gas if argon is used, but will be formed in a helium cover gas.

High pressure scandium halide discharge lamp - has transparent aluminium oxide tube with phosphors, starting and buffer gases

Abstract: The high pressure metal vapour discharge lamp contains a transparent aluminium oxide tubular burner containing a buffer gas, respective phosphors, and a starting rare gas. The gas mixture contains 1.80 x 10-7 to 9.27 x 10-6 g. mol. of a scandium halide, such as scandium iodide, scandium bromide or scandium chloride per each cubic cm. of the tubular burner inner space, to which is added at least 3.1 times quantity of metallic scandium, calculated as atomic ratio of free scandium to that bound in the halide. The metallic scandium forms the phosphor. Various other scandium halide and metallic scandium ratios may be used. Preferably the lamp containts an additional quantity of a halide of an alkali metal, of a metal from the titanium group a metal of the niobium group and/or the rare earths.