The application of XPS to the determination of the kinetics of the co oxidation reaction over the Ir(111) surface

The coverages of adsorbed oxygen and CO on an Ir(111) surface have been determined using X-ray photoelectron spectroscopy (XPS) during the steady-state catalytic production of CO₂. Correlating the coverages of the reacting adsorbates with the rate of CO₂ production allows the kinetics of the CO oxidation reaction to be determined. The reaction is found to obey a Langmuir-Hinshelwood rate expression of the form , where R_CO2 is the rate of CO₂ production, k⁰ is the pre-exponential factor of the reaction rate coefficient, [CO] and [O] are the surface coverages of CO and oxygen, respectively, and E_a is the activation energy for the oxidation reaction. The activation energy for this catalytic oxidation reaction is found to be approximately 9 $\text{kcal}\text{mole}$.     

Slow magnetic fields of the brain preceding movement and speech

Summary Magnetic fields of the brain were recorded preceding selfinitiated finger, foot, toe movements, stimulus-triggered finger and toe movements, and speech. Slow magnetic-field shifts were found with morphology similar to coincident electrical potentials, but with very different distributions. Inferences from the data about localization of cerebral generators were discussed. These studies were supported by grants from the B.C. Research Council and N.S.E.R.C. of Canada.     

On the energy-momentum tensor in gauge field theories

The energy-momentum tensor in spontaneously broken non-Abelian gauge field theories is studied. The motivation is to show that recent results on the finiteness and gauge independence of S-matrix elements in gauge theories extends to observable amplitudes for transitions in a gravitational field. Path integral methods and dimensional regularization are used throughout. Green's functions Γ_μν^(j)(q; p₁,…,p_j) involving the energy-momentum tensor and j particle fields are proved finite to all orders in perturbation theory to zero and first order in q, and finite to one loop order for general q. Amputated Green's functions of the energy momentum tensor are proved to be gauge independent on mass shell.     

The nature of the oxide barrier in inelastic electron tunneling spectroscopy

We have investigated the insulating barrier of A1-oxidized A1Pb tunnel junctions. This study was effected by measuring the inelastic electron tunneling (IET) spectra of various junctions in which the insulator was formed by oxidizing the aluminum either in an O₂ H₂O or D₂O plasma discharge at various temperatures between room temperature and 250°C. We found that those insulators formed at all temperatures in 0₂ and those formed at high temperatures (?150°C) in H₂O and D₂O are aluminum oxide with no evidence for any appreciable bulk hydroxide. The surfaces of these insulators do have adsorbed hydroxyl groups present, however. The insulators made at lower temperatures (<100°C) are also primarily aluminum oxide, but there is evidence for some bulk hydroxide. These “oxides” have a high concentration of surface hydroxy1 groups with indications of two types of surface hydroxyls.     

Spherical symmetry and magnetic monopoles

I give a general, gauge-invariant, definition of spherical symmetry in a gauge theory. I show that if the fields are required to be non-singular at the origin, such symmetry can occur only for certain values of the magnetic charge. One consequence is the existence of stable monopoles which are not spherically symmetric.     

S-Shaped Response Functions: Implications for Decision Models

This paper discusses the implications for analysis and parameter estimation of optimization using S-shaped (convex-concave) response functions.     

Pions in large N quantum chromodynamics

An effective field theory of quarks, gluons, and pions, with the number N of colors treated as large, is proposed as a basis for calculations of hadronic phenomena at moderate energies. The qualitative consequences of the large N limit are similar though not identical to those in pure quantum chromodynamics, but because constituent quark masses appear in the effective Lagrangian, the 't Hooft coupling in the effective theory need not be strong at moderate energies. To leading order in 1/N the effective theory is renormalizable, with only a finite number of terms in the Lagrangian.