Intensity dependence of hydrogen Lyman alpha and Balmer alpha lines upon cathode material of an abnormal glow discharge

The results of the hydrogen L _a_{\alpha} 121.567 nm and H _a_{\alpha} 656.280 nm line intensity dependence upon cathode material of an abnormal glow discharge are reported. Under similar experimental conditions systematic variation of the L _a_{\alpha} and H _a_{\alpha} line intensity with the atomic number Z of cathode material (graphite, Ti, Fe, Cu, Zn, Pd, Ag, Pt, Au and Pb) is detected. Shapes of line intensity Z-dependences suggest that, apart from electron impacts, line excitation is related also to the back-scattering of fast hydrogen atoms from cathode and sputtering yield of cathode material. The excitation of H₂ molecular bands is not sensitive to these cathode processes.     

Comparative analysis of the two‐constant generalizations of hooke's law for isotropic elastic materials at finite strains

For ten models of the isothermal behavior of materials, the solutions of boundaryvalue problems are studied for five types of the experimentally reproducible uniform stress–strain state with unchanged directions of the principal axes. It is found that, for three models, the governing equations are similar to the relations of Hooke's law and valid within the same range of the ratio between the shear and bulk moduli. In these models, the specific strain energy can be represented as a sum of the energies due to changes in volume and shape. The ranges where the other three known models exhibit incorrect behavior are determined.     

Experimental study of aerodynamic characteristics of a reentry vehicle on a setup with free oscillations at supersonic velocities

A setup with free oscillations containing a transverse sting for holding the test model and possible test regimes are described. The method of testing and data processing is presented. Aerodynamic characteristics of the pitching moment of the model in a wide range of Mach numbers are obtained. Comparisons of quasi-steady data with numerical predictions and of damping derivatives with those obtained previously in tests of the model mounted on the base sting and with calculated results are performed. The model is found to be statically and dynamically stable except for regimes with М = 1.75 and 2.25, where nondecaying oscillations are excited.     

Letter: A simple ion source set-up for desorption/ionization on silicon with ion mobility spectrometry and ion mobility spectrometry-mass spectrometry

Using a simple ion source set-up, laser desorption/ionization on silicon (DIOS) was demonstrated with the use of a custom-made drift tube ion mobility spectrometer (IMS), mounted on a commercial triple quadrupole mass spectrometer, and with an IMS equipped with a Faraday plate detector. DIOS was tested by mobility measurement of tetrapropylammonium iodide, tetrabutylammonium iodide and tetrapentylammonium iodide, whilst 2,6-di-tert- butylpyridine was used as a standard. The reduced mobilities measured for the test halides are in concordance with previously obtained ion mobility spectrometry-mass spectrometry data.     

Alkyltributylphosphonium chloride ionic liquids: synthesis, physicochemical properties and crystal structure

A series of alkyltributylphosphonium chloride ionic liquids, prepared from tributylphosphine and the respective 1-chloroalkane, C(n)H(2n+1)Cl (where n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 or 14), is reported. This work is a continuation of an extended series of tetraalkylphosphonium ionic liquids, where the focus is on the variability of n and its impact on the physical properties, such as melting points/glass transitions, thermal stability, density and viscosity. Experimental density and viscosity data were interpreted using QPSR and group contribution methods and the crystal structure of propyl(tributyl)phosphonium chloride is detailed.