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Full-Text Articles in Physics

On Electromagnetic And Quantum Invisibility, Pattabhiraju Chowdary Mundru Jul 2014

On Electromagnetic And Quantum Invisibility, Pattabhiraju Chowdary Mundru

Doctoral Dissertations

The principle objective of this dissertation is to investigate the fundamental properties of electromagnetic wave interactions with artificially fabricated materials i.e., metamaterials for application in advanced stealth technology called electromagnetic cloaking. The main goal is to theoretically design a metamaterial shell around an object that completely eliminates the dipolar and higher order multipolar scattering, thus making the object invisible.

In this context, we developed a quasi-effective medium theory that determines the optical properties of multi-layered-composites beyond the quasi-static limit. The proposed theory exactly reproduces the far-field scattering/extinction cross sections through an iterative process in which mode-dependent quasi-effective impedances ...


Pressure Cell For Magnetostrictive Measurements, Jerome E. Ostenson, Douglas K. Finnemore, David C. Jiles Feb 1989

Pressure Cell For Magnetostrictive Measurements, Jerome E. Ostenson, Douglas K. Finnemore, David C. Jiles

Ames Laboratory Publications

A pressure cell has been designed to study the magnetostrictive properties of a material as a function of both pressure and magnetic field. For changes in length on the order of 2000 ppm, it is necessary to have a substantial compliance in the pressure cell to retain a constant stress over the length of travel.


Binding Energies Of The Light Hyperfragments , James Thomas Jones Jr. Jan 1956

Binding Energies Of The Light Hyperfragments , James Thomas Jones Jr.

Retrospective Theses and Dissertations

No abstract provided.


Magnetic Properties Of Gd-La And Gd-Y Alloys , Wilbur Collins Thoburn Jan 1956

Magnetic Properties Of Gd-La And Gd-Y Alloys , Wilbur Collins Thoburn

Retrospective Theses and Dissertations

No abstract provided.


Ferromagnetic-Antiferromagnetic Phase Transitions , Thomas James Hendrickson Jan 1956

Ferromagnetic-Antiferromagnetic Phase Transitions , Thomas James Hendrickson

Retrospective Theses and Dissertations

No abstract provided.


Electrical Properties Of Magnesium Silicide And Magnesium Germanide , Charles R. Whitsett Jan 1955

Electrical Properties Of Magnesium Silicide And Magnesium Germanide , Charles R. Whitsett

Retrospective Theses and Dissertations

No abstract provided.


Intensities In The Hollow Cathode Discharge , John Philip Heller Jan 1953

Intensities In The Hollow Cathode Discharge , John Philip Heller

Retrospective Theses and Dissertations

The experimental part of this research involved measurements of the brightness of a hollow cathode discharge in the light of various wavelengths of the first spark spectrum of aluminum. The hollow cathode tube was constructed in accord with modern specifications for a light source for high resolution spectroscopy. The line brightnesses were measured under various conditions of operation of the discharge tube. The external parameters which were varied were discharge current, cathode temperature, carrier gas pressure and cathode diameter;The motivation for the experiment was two-fold. Firstly it was desired to obtain empirical information on the optimum conditions for the ...


Transmission Of 0-50 Kilovolt Electrons By Thin Films With Applications To Beta-Ray Spectroscopy , Raymond O. Lane Jan 1953

Transmission Of 0-50 Kilovolt Electrons By Thin Films With Applications To Beta-Ray Spectroscopy , Raymond O. Lane

Retrospective Theses and Dissertations

No abstract provided.


Electrical Properties Of Crystalline Boron , William Corr Shaw Jan 1953

Electrical Properties Of Crystalline Boron , William Corr Shaw

Retrospective Theses and Dissertations

The boron crystals used in this study were prepared by reducing boron tribromide with hydrogen upon contact with a hot (1500°C) tantalum filament. The largest single crystals weighed less than ten micrograms and were a few hundred microns in length. The high purity of the specimens was verified spectrographically and their crystalline nature was verified by means of Laue photographs;Micromanipulative techniques for mounting very small crystals with several electrical contacts were developed. Microscopic single crystals of boron were mounted with as many as five spring loaded tungsten probes. Measurements were made of voltage current characteristics, resistivity, Hall and ...


A Proportional Counter Spectrometer Study Of The Beta-Decay Of Radioactive S35, Pm147, Ni63, And C14 , Jack Pitts Mize Jan 1953

A Proportional Counter Spectrometer Study Of The Beta-Decay Of Radioactive S35, Pm147, Ni63, And C14 , Jack Pitts Mize

Retrospective Theses and Dissertations

No abstract provided.


Role Of Triple Collisions In Excitation Of Molecular Vibrations , Richard Alden Walker Jan 1952

Role Of Triple Collisions In Excitation Of Molecular Vibrations , Richard Alden Walker

Retrospective Theses and Dissertations

No abstract provided.


The Resistivity Of Lanthanum, Cerium, Praseodymium And Neodymium At Low Temperatures , Nancy Rennie James Jan 1952

The Resistivity Of Lanthanum, Cerium, Praseodymium And Neodymium At Low Temperatures , Nancy Rennie James

Retrospective Theses and Dissertations

No abstract provided.


The Determination Of The Thermionic Work Function Of Nickel By A New Method , Robert Mcneil Bowie Jan 1933

The Determination Of The Thermionic Work Function Of Nickel By A New Method , Robert Mcneil Bowie

Retrospective Theses and Dissertations

I. The work function of nickel was determined thermionically and found to be 5.03 +/- .05 volts. The constant A was found to be 1.38 x 103 amps/cm2deg 2;II. A new method was developed for determining the thermionic work function of metals. It differs from the conventional method in the following respects: (1) The metal is in the form of a rough sphere. (2) It is heated by electron bombardment from an auxiliary filament. (3) Measurements are made as the metal cools. (4) The emission current charges a condenser which is discharged through a galvanometer at pre-determined ...


A Magneto-Optic Method Of Determining The Vitamin Content Of Various Substances , Gerrit Martin Wissink Jan 1933

A Magneto-Optic Method Of Determining The Vitamin Content Of Various Substances , Gerrit Martin Wissink

Retrospective Theses and Dissertations

In this investigation the magneto-optic apparatus was used. This apparatus was modified to some extent from the original apparatus used by Allison. The modifications included a mercury vapor arc and a monochromator to furnish a steady source of monochromatic light, as well as a photoelectric cell circuit and amplifier to read the minima. Only half of the bilateral trolley system used by Allison was employed;The apparatus gave evidence of a distinct minimum which seemed characteristic of vitamin A. This minimum was located at 32.90 on the light path scale. Pure carotene did not give this minimum. Pure carotene ...