Investigation of Gas Degradation in CO2 ? N2 Pulse Discharges I. Long Term Behaviour of Pulsed Laser Discharges in CO2 — N2 Gas Mixtures

The correlation between the plasma resistance and the laser output parameters has been investigated in pulsed CO₂ — N₂ discharges. The strong increase of the discharge resistance during gas degradation can be explained on the basis of strong attaching gas components. In degraded mixtures a supression of discharge instabilities together with the restoration of the laser pulse energy is possible by increasing the reduced electric field E/N temporarily.     

Two nonisomorphicK-automorphisms with isomorphic squares

By taking two different skew products of an initial transformation and a two point space, two measure preserving transformations with the same square are constructed. By direct arguments on the doubly infinite partition names of points in these processes, they are shown to beK-automorphisms and non-isomorphic. This work is a part of the author’s Ph.D. dissertation written at Stanford University under D. S. Ornstein.     

Molecular structure of F2POPF2: an electron diffraction study

The most important geometric parameters and associated uncertainties (2σ) determined for F₂POPF₂ are the distances (r_g) P-O = 1.631 ± 0.010 Å, P-F = 1.568 ± 0.004 Å, and angles POP = 135.2 ± 1.8°, OPF = 97.6 ± 1.2°, and FPF = 99.2 ± 2.4°. Amplitudes of vibration were also found. The large POP angle and relatively short P-O bond length are consistent with a significant degree of pπ-dπ bonding. Our structure interpretation differs from an earlier one reported by Arnold and Rankin in the relative P-O and P-F bond lengths and in the conclusion that the molecule exists in a distribution of not very rigid, probably staggered, conformers instead of one fairly rigid structure.     

The (3He,n) reaction on 16O and 18O

The (³He, n) reaction on ¹⁶O and ¹⁸O has been used to study low-spin states in ¹⁸Ne and ²⁰Ne up to E_x ≈ 8 and 20 MeV, respectively. The measured neutron angular distributions have been analysed using DWBA. By a comparison with shell-model calculations in the (s, d) shell it is found that most of the two-proton transfer strength can be explained within that shell. Important contributions, however, from the (f, p) shell in low-lying negative parity states are also present.     

Properties of unbound high-spin states in27Al

Selectively excited high-spin states in²⁷Al have been located by the reaction¹²C(¹⁶O,p)²⁷Al. The excitation functions of these states have been measured at incident energiesE _cm=18.7 to 30.1 MeV at intervals of 150 keV. They exhibit maxima of presumably non-statistical origin. At four different energies the subsequent decay of the²⁷Al states has been studied by detecting the final heavy recoils with the Munich recoil spectrometer in coincidence with the proton emitted in the first stage of the reaction. Using this new method branching ratios of theγ-, α-, andn-decay have been measured. Based on angular correlation arguments spins up to 27/2? have been determined within the experimental accuracy of 1–2?. The observations suggest a superdeformed shape of²⁷Al at least in some of the states.     

Quark-antiquark recombination in the fragmentation region

Meson production at low transverse momentum in the fragmentation region (x>0.5) in pp collisions is considered in the context of the parton model. It is shown that the quark decay process is unimportant compared to the quark-antiquark recombination process. The calculated results of the model agree very well with the experimental data on the longitudinal momentum distributions of π^± and K^± in both the shapes and the normalizations.     

Computer readable analytical chemical data - comments on a critical need

Do academics, journal editors and research funding agencies place too little emphasis on the compilation of high quality data collections? Stephen Heller and Rudolph Potenzone think so, and contrast this situation with that found in industry, where large databanks abound.     

Two nonisomorphicK-automorphisms all of whose powers beyond one are isomorphic

As in the earlier example of two nonisomorphicK-automorphisms with isomorphic square by building an appropriate skew product of aK-automorphism that is not Bernoulli with an algebraic fiber, we get all powers beyond one of the two nonisomorphic transformations to be isomorphic. Furthermore, all the isomorphism maps are finite codings of the constructed partition names.