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Sigma-bonded alkyl compounds of niobium and tantalum - trimethyldichloroniobium and trimethyldichlorotantalum.
Synthesis and formula determination of sigma bonded trimethyldichloroniobium and trimethyldichlorotantalum
Dynamics of T equal 2 sigma-pi system. I.
Dynamic calculation for 2 sigma pi resonant system /meson-baryon/ in P 3/2 state, using Balaz type N/D method
Partial wave theory of H sub 2 - Calculation of sigma sub g super plus states.
Partial wave theory of two electron diatomic hydrogen molecules and calculation in zeroth order for sigma g states
Sigma phase formation and its effect on stress-rupture properties of IN-100
Sigma phase formation and its effect on stress rupture properties of nickel base alloy IN-100
An analysis of the effect of integral and sigma pulse frequency modulation on white noise.
Integral and sigma pulse frequency modulation effects on white noise, analyzing autocorrelation and spectral density functions of PFM system output
Further observations on the formation of sigma phase in a nickel-base superalloy /IN-100/
Formation of sigma phase in nickel base superalloy
Alloy chemistry of sigma /beta-U/-related phases. II
Extension characteristics of delta and sigma related phases in Mo-Ni ternary systems and evaluation of unit cell dimension variations on alloying
The atmosphere of the hydrogen-deficient star sigma Orionis E
Sigma Orionis E hydrogen-deficient atmosphere, using grid of constant-flux model atmospheres to determine abundances of five elements
Mid-latitude rocket observations of the altitude profile of the O2 /a /1 Delta g//-/X /3 Sigma g plus// transition
Nike-Apache rocket carrying radiometer for detection of O2 /a /1 Delta g//-/X /3 Sigma g plus// transition
Deactivation of N2A 3 Sigma u plus molecules in the aurora
Analysis of N2A 3 Sigma u positive molecule deactivation in auroras using atmospheric model based on mass spectrometer measurements
Excitation of the metastable E(3 Sigma g plus) state of N2 by electron impact
The contribution of the N2(E(3 Sigma g plus)) state to the total metastable excitation function of N2 assessed on the basis of time-of-flight studies of metastable nitrogen molecules. The cross section for electron impact excitation state was determined in the domain of the resonance form threshold (11.87 eV) to an energy of about 13 eV. The maximum value of the cross section was found to be (7.0 + or - 4.0) x 10 to the -18th power sq cm at an energy of 12.2 eV. The measurement was made absolute by using the previously determined yield of the metastable detector, the lifetime of the E state, and by eliminating the energy spread in the electron beam from the raw data. The half-width (FWHM) of the resonance-like excitation function near threshold was found to be about 0.4 eV. No substantial evidence was obtained from the present data for the presence of the nonresonant part of the excitation function for the state studied.
Spectrocopic measurements of water vapor plasmas at high resolution: The optical transition probabilities for OH (A 2 Sigma - X 2 Pi)
Emission and absorption spectra of water vapor plasmas generated in a wall-stabilized arc at atmospheric pressure and 4 current, and at 0.03 atm and 15 to 50 A, were measured at high spatial and spectral resolution. The gas temperature was determined from the shape of Doppler-broadened rotational lines of OH. The observed nonequilibrium population distributions over the energy levels of atoms are interpreted in terms of a theoretical state model for diffusion-controlled arc plasmas. Excellent correlation is achieved between measured and predicted occupation of hydrogen energy levels. It is shown that the population distribution over the nonpredissociating rotational-vibrational levels of the A 2 Sigma state of OH is close to an equilibrium distribution at the gas temperature, although the total density of this state is much higher than its equilibrium density. The reduced intensities of the rotational lines originating in these levels yielded Boltzmann plots that were strictly linear.
Vibrational population of the A super 3 sigma sub u/+/ and B super 3 pi sub g states of N2 in normal auroras.
Use of new electron impact excitation cross sections for the six lowest triplet states (A, B, W, C, E, D) of N2, and solution of the coupled equations of statistical equilibrium to obtain the vibrational population of each electronic state. The results show that cascade from high levels of the A super 3 sigma sub u(+) state and from the W super 3 delta sub u state is significant in populating the lower vibrational levels of the B state and hence the character of its ?apparent' excitation cross sections. For the B state excited under auroral conditions, the fraction of the total population due to cascade processes exceeds 25% for all levels lower than 7 and is greater than 80% for B(v' = 0). For the A state under similar conditions, cascade from the B state contributes 50% or more of the total vibrational population for levels lower than 7, and 80% or more for levels below 4. For levels of the A state greater than 7, the A yields B transitions depopulate the levels rapidly and indicate that the Vegard-Kaplan emissions from these higher levels will be weak or totally absent in normal auroras.
Oscillator strengths for the X/1 Sigma+/ - A/1 Pi/ system of CH+.
Oscillator strengths for the X/1 Sigma+/ - A/1 Pi/ system of CH+ computed to an estimated accuracy of 10 percent from ab initio wave functions are presented. These oscillator strength values are given for the two strongest interstellar lines of 4232 and 3957 A.
Eutectic superalloys strengthened by sigma, Ni3CB lamellae and gamma prime, Ni3Al precipitates
By means of a screening and solidification optimization study of certain alloys located on the gamma-sigma liquidus surface within the Ni-Cb-Cr-Al system, alloys with high temperature properties superior to those of all known superalloys were defined. One alloy, Ni - 19.7w/o Cb - 6.0w/o Cr - 2.5w/o Al, directionally solidified at 3 cm/hr met or exceeded each program goal. A second alloy, Ni-21.75 w/o Cb-2.55 w/o Al, although deficient in its inherent oxidation resistance, met the other program goals and combined a remarkable insensitivity of composite microstructure to solidification parameters with excellent low temperature toughness. This investigation demonstrated that useful properties for gas turbine airfoil application have been achieved by reinforcing a strong and tough gamma solid solution matrix containing precipitated gamma prime by a lamellar intermetallic compound Ni3 Cb having greater strength at elevated temperature.
Automated system for measurement, collection and processing of hydrometeorological data aboard scientific research vessels of the GUGMS (SIGMA-s)
A report is made on the automated system known as SIGMA-s for the measurement, collection, and processing of hydrometeorological data aboard scientific research vessels of the Hydrometeorological Service. The various components of the system and the interfacing between them are described, as well as the projects that the system is equipped to handle.