4,594 research outputs found
A Simple Pendulum Determination of the Gravitational Constant
We determined the Newtonian Constant of Gravitation G by interferometrically
measuring the change in spacing between two free-hanging pendulum masses caused
by the gravitational field from large tungsten source masses. We find a value
for G of (6.672 34 +/- 0.000 14) x 10^-11 m^3 kg^-1 s^-2. This value is in good
agreement with the 1986 Committee on Data for Science and Technology (CODATA)
value of (6.672 59 +/- 0.000 85) x 10^-11 m^3 kg^-1 s^-2 [Rev. Mod. Phys. 59,
1121 (1987)] but differs from some more recent determinations as well as the
latest CODATA recommendation of (6.674 28 +/- 0.000 67) x 10^-11 m^3 kg^-1 s^-2
[Rev. Mod. Phys. 80, 633 (2008)].Comment: 10 pages, 2 figure
Stage properties, costumes, scenery and music of the English miracle plays
Thesis (M.A.)--University of Illinois, 1906.Typescript.Includes bibliographical references (leaves 28-30)
Welding high-strength aluminum alloys
Handbook has been published which integrates results of 19 research programs involving welding of high-strength aluminum alloys. Book introduces metallurgy and properties of aluminum alloys by discussing commercial alloys and heat treatments. Several current welding processes are reviewed such as gas tungsten-arc welding and gas metal-arc welding
Studies of the auroral substorm. III CONCEPT of the magnetospheric substorm and its relation to electron precipitation and micropulsations
Concept of auroral magnetospheric substorm and relation to electron precipitation and micropulsation
A Preliminary Study of Solar Powered Aircraft and Associated Power Trains
The feasibility of regeneratively powered solar high altitude powered platform (HAPP) remotely piloted vehicles was assessed. Those technologies which must be pursued to make long duration solar HAPPs feasible are recommended. A methodology which involved characterization and parametric analysis of roughly two dozen variables to determine vehicles capable of fulfilling the primary mission are defined. One of these vehicles was then conceptually designed. Variations of each major design parameter were investigated along with state-of-the-art changes in power train component capabilities. The midlatitude mission studied would be attainable by a solar HAPP if fuel cell, electrolyzer and photovoltaic technologies are pursued. Vehicles will be very large and have very lightweight structures in order to attain the combinations of altitude and duration required by the primary mission
Studies of the auroral substorm. I - Characteristics of modulated energetic electron precipitation occurring during auroral substorms
Characteristics of modulated energetic electron precipitation occurring during auroral substorm
Validity of the Gor'kov expansion near the upper critical field in type II superconductors
We have examined the validity of the Gor'kov expansion in the strength of the
order parameter of type II superconductors near the upper critical field.
Although the degeneracy of the electron levels in a magnetic field gives non-
perturbative terms in the solution to the Bogoliubov-de Gennes equations we
find, contrary to recent claims, that these non-perturbative terms cancel in
the expression for the thermodynamic potential, and that the traditional
Gor'kov theory is correct sufficiently close to Hc2 at finite temperature. We
have derived conditions for the validity of the Gor'kov theory which
essentially state, that the change in the quasiparticle energies as compared to
the normal state energies cannot be too large compared to the temperature.Comment: 5 pages, 3 figures. One reference adde
Electric field effect on superconductivity at complex oxide interfaces
We examine the enhancement of the interfacial superconductivity between
LaAlO and SrTiO by an effective electric field. Through the
breaking of inversion symmetry at the interface, we show that a term coupling
the superfluid density and an electric field can augment the superconductivity
transition temperature. Microscopically, we show that an electric field can
also produce changes in the carrier density by relating the measured
capacitance to the density of states. Through the electron-phonon induced
interaction in bulk SrTiO, we estimate the transition temperature.Comment: 7 Pages, Submitted to Physical Revie
Thermodynamic properties of Bi2Sr2CaCu2O8 calculated from the electronic dispersion
The electronic dispersion for Bi2Sr2CaCu2O(8+d) has been determined from
angle-resolved photoelectron spectroscopy (ARPES). From this dispersion we
calculate the entropy and superfluid density. Even with no adjustable
parameters we obtain an exceptional match with experimental data across the
entire phase diagram, thus indirectly confirming both the ARPES and
thermodynamic data. The van Hove singularity is crossed in the overdoped region
giving a distinctive linear-in-T temperature dependence in the superfluid
density there.Comment: 5 pages, 4 figures, submitted to Physical Review Letter
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