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Microwave Properties of Hyaluronate Solutions Using a Resonant Microwave Cavity as a Probe (open access)

Microwave Properties of Hyaluronate Solutions Using a Resonant Microwave Cavity as a Probe

Physiological functions of a biomacromolecule seem to be closely related to its molecular conformations. The knowledge of any conformational changes due to changes in its environment may lead to a proper understanding of its functions. Hyaluronic acid, a biomacromolecule with unusually high molecular weight and some important biological functions is the subject of the present work. A temperature-dependent transition in hyaluronate solution of 120 mg/ml concentration was observed at physiological temperature. It is shown that this temperature-dependent behavior can be related to the orientational polarizability term in the Debye theory of polar molecules in liquids.
Date: May 1980
Creator: Jani, Shirish K.
System: The UNT Digital Library
Phase Transition Studies in Polar and Nonpolar Liquids at Microwave Frequencies (open access)

Phase Transition Studies in Polar and Nonpolar Liquids at Microwave Frequencies

A resonant microwave cavity technique was employed to study the dielectric behavior of some polar and non-polar liquids near the phase transition temperatures at microwave frequencies of 7.2, 9.2 and 10.1 GHz. The Slater perturbation equations for a resonant microwave cavity are briefly discussed to show that the above technique can be used to determine both the real and imaginary parts of dielectric response. Abrupt changes in dielectric response were observed near the phase transition temperatures for the polar liquids studied in this investigation. The dielectric relaxation phenomenon in liquids has been treated as a chemical rate process and the abrupt change in the dielectric response of the liquids near phase transition temperatures is shown to be related to the dramatic changes in the free energy of activation of the molecules. Some values of the free energy of activation were deduced for the various compounds from data obtained in this investigation.
Date: August 1980
Creator: Dahiya, Jai N. (Jai Narain)
System: The UNT Digital Library
The Size Effect on the Galvanomagnetic Properties of a Semiconductor (open access)

The Size Effect on the Galvanomagnetic Properties of a Semiconductor

A theory is developed to explain the dependence of carrier transport in a thin semiconducting film on film thickness, magnetic field strength, and the dominant bulk scattering mechanism. This theory is based on the solution of the linearized Boltzmann equation in relaxation time form. The semiconductor is assumed to be bounded and nondegenerate with spherical energy surfaces and a scalar effective mass, It is also assumed to be flat banded with totally diffuse scattering at the surface. Classical Boltzmann statistics are used for equilibrium. The dependence of the relaxation time on the carrier energy is approximated by a power law equation. The principle improvement over similar theories is the treatment of the dependence of the relaxation time on carrier energy. The power law approximation for this dependence is valid for randomizing and elastic scattering mechanisms.
Date: August 1980
Creator: Smith, V. Devon (Vernon Devon)
System: The UNT Digital Library