On the maximum of the k-dependent susceptibility for fixed k and T > Tc

We study the maximum occuring in ${}_{\mathrm{x}}\text{(}\text{k}\text{, T)}$ for fixed k at a temperature T_max > T_c. We examine the predictions of both Ornstein-Zernike and ?-expansions for the position of this maximum. These are compared with the exact results fot the two-dimensional Ising model.     

Observation of shallow residual donors in high purity epitaxial GaAs by means of photoluminescence spectroscopy

We report the first observation of three different residual donors in undoped high purity vapor phase epitaxial GaAs using the high resolution photoluminescence spectroscopy technique at temperatures ～ 2 K. The binding energies of these shallow donors were determined from the excited state transitions of excitons bound to neutral donors and they are found to be in very good agreement with corresponding values obtained from high-resolution far infrared Fourier transform spectroscopy, using the modulated photoconductivity technique.     

The sl2 Loop Algebra Symmetry of the Six-Vertex Model at Roots of Unity

We demonstrate that the six vertex model (XXZ spin chain) with =(q+q^-1)/2 and q^2N=1 has an invariance under the loop algebra of sl₂ which produces a special set of degenerate eigenvalues. For =0 we compute the multiplicity of the degeneracies using Jordan–Wigner techniques.     

General relationships between the mobility of a chain fluid and various computed scalar metrics

We performed molecular dynamics simulations of chain systems to investigate general relationships between the system mobility and computed scalar quantities. Three quantities were found that had a simple one-to-one relationship with mobility: packing fraction, potential energy density, and the value of the static structure factor at the first peak. The chain center-of-mass mobility as a function of these three quantities could be described equally well by either a Vogel-Fulcher type or a power law equation.     

Determination of azarole plus its reduction product by HPLC

An analytical methodology for the assay of azarole plus its reduced product in plasma was developed. The method consists of oxidation of the sample with potassium ferrocyanide, extraction, and subsequent analysis by high performance liquid chromatography. Assays of prepared plasma samples demonstrated an overall precision of +/- 6.2%; accuracy ranged from -9.1% low to 5.1% high, based on mean values at several concentrations. Analysis of variance for the effects of concentration, time, and the interactive term concentration X time were all insignificant.     

Relatively Hyperimmune Relations on Structures

Let be a computable structure and let R be an additional relation on its domain. We establish a necessary and sufficient condition for the existence of an isomorphic copy of such that the image of R is h-simple (h-immune) relative to .     

The Perturbation ϕ2, 1 of the M(p,p + 1) Models of Conformal Field Theory and Related Polynomial-Character Identities

Using q-trinomial coefficients of Andrews and Baxter along with the technique of telescopic expansions, we propose and prove a complete set of polynomial identities of Rogers-Ramanujan type for M(p, p + 1) models of conformal field theory perturbed by the operator _{2, 1}. The bosonic form of our polynomials is closely related to corner transfer matrix sums which arise in the computation of the order parameter in the regime 1⁺ of A _p–1 dilute models. In the limit where the degree of the polynomials tends to infinity our identities provide new companion fermionic representations for all Virasoro characters of unitary minimal series.     

Convergence of the cluster-variation method for a system on a triangular lattice

The paper studies the convergence of the cluster-variation method to the rigorous result as the cluster size increases. The calculation is done on the phase boundary at T = 0 between the A₂B-type ordered phase and the disordered phase on a two-dimensional triangular lattice with nearest-neighbor interaction. It is shown that the phase boundary at (T = 0) is obtained by maximizing the entropy under the constraint that only a limited number of atomic configurations are allowed. Formulations are developed for clusters of n = 3, 5, 7, 9,11, and 13 points. When thermodynamic quantities which are calculated using these clusters are plotted against 1/n, they approach the known rigorous (n = ∞) results more or less linearly but with a pseudo-period of δn = 6. An exception is the square of the long-range order, which bends down as 1/n tends to zero.