Automatic tuning of a superconducting cavity using optical feedback.
Automatic tuning of superconducting cavity resonant frequency using optical feedback, discussing phase error processing and frequency deviation
Baker, G. L.↗
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Microbalance accurately measures extremely small masses
Oscillating fiber microbalance has a vibrating quartz fiber as balance arm to hold the mass to be weighed. Increasing fiber weight decreases its resonant frequency. Scaler and timer measure magnitude of the shift. This instrument withstands considerable physical abuse and has calibration stability at normal room temperatures.
Patashnick, H.↗
The density of eigenvalues in thin circular conical shells
Resonant frequencies in thin circular conical shells
Hart, F. D.↗
Inhomogeneous plasma oscillations in streaming plasmas
Inhomogeneous plasma oscillations in counterstreaming plasmas analyzed for electric fields and resonant frequencies from Vlasov equation
Baker, J. C.↗
Temperature-dependent magnon-energy theory of FeF2 and MnF2
Magnon energy theory for temperature dependence of ferrous and magnesium fluorides antiferromagnetic- resonance frequency, sublattice magnetization and magnetic specific heat
Nagai, O.↗
Nuclear quadrupole resonance study of the inductive effect in chemical bonding in chloroalkenes
Inductive effect in C-Cl chemical bonds in chloroalkenes, using nuclear quadrupole resonance frequencies shifts
Koltenbah, D. E.↗
An analysis of Alouette I plasma resonance observations
Alouette 1 plasma resonance observations, analyzing electron density measurements in sheath region and cyclotron harmonic resonant frequencies
Benson, R. F.↗
Equivalent spring-mass system for normal modes
Mass matrix and resonant frequencies for generating equivalent spring-mass models for normal modes of structural subsystem
Bamford, R. M.↗
The use of electroacoustic resonances to determine electron density profiles
Unknown electron density profiles determined from electroacoustic resonance frequencies by WKB approximation
Baird, A. W., III↗
Vibrating element electrometer with output signal magnified over input signal by a function of the mechanical Q of the vibrating element Patent
Vibrating element electrometer producing high conversion gain by input current control of elements resonant frequency displacement amplitude
Coon, G. W.↗
Apparatus for detecting the amount of material in a resonant cavity container Patent
Quantitative liquid measurements in container by resonant frequencies
Miller, J. C.↗
Instrumentation for liquid hydrogen density measurements using an open-ended microwave cavity
Resonant frequency measurement systems used in conjunction with open-ended microwave cavity to continuously monitor density of liquid hydrogen in flow system
Smetana, J.↗
New detection method for rolling element and bearing defects
Instrument for detecting defects in rolling elements of bearings is described. Detection depends on rate at which rolling elements impact defect and establishes envelope amplitude of ball resonant frequency. Block diagram of instrument is provided and results obtained in conducting tests are reported.
Burchill, R. F.↗
Cavity perturbation techniques for measurement of the microwave conductivity and dielectric constant of a bulk semiconductor material.
Cavity perturbation techniques offer a very sensitive and highly versatile means for studying the complex microwave conductivity of a bulk material. A knowledge of the cavity coupling factor in the absence of perturbation, together with the change in the reflected power and the cavity resonance frequency shift, are adequate for the determination of the material properties. This eliminates the need to determine the Q-factor change with perturbation which may lead to appreciable error, especially in the presence of mismatch loss. The measurement accuracy can also be improved by a proper choice of the cavity coupling factor prior to the perturbation.
Eldumiati, I. I.↗
Laser with a transmitting window.
The effect of transmission of radiation through one mirror of a laser is investigated. For a laser oscillator the result is to change the effective resonance frequency and Q of the cavity. Using the same model for the cavity, a signal is injected into the active medium through the transmitting window, and its effect on the system studied. When the external signal is strong enough and sufficiently close to the natural frequency of the laser oscillator, the laser locks its frequency to the input signal. The equations describing the system are solved over the range of input frequencies where the laser is locked, and the resulting gain found. In the high-intensity limit the medium saturates, and the gain tends to that of a lossy cavity. As the input intensity vanishes, the gain approaches infinity and the system tends to a laser oscillator.
Spencer, M. B.↗
Quartz microbalance studies of an adsorbed helium film.
The resonant frequency of a quartz crystal oscillating in the thickness-shear mode changes by virtue of the mass loading due to any type of film laid down on its surfaces. For a helium film only the normal fraction remains rigidly coupled to the substrate motion. Adsorption isotherms of He-4 measured with this technique show clear departures from conventional nonsuperfluid behavior. We attribute this effect to the onset and presence of superfluidity in the film.
Chester, M.↗
Monitor for physical property changes in solid propellants
Specially designed sensor is attached to or imbedded in propellant. When sensor is driven into vibration, it moves with a phase lag directly proportional to internal friction or loss coefficent. Resonance frequency of the system is related to Young's modulus. Modulus or internal friction can be monitored over long period of time.
Black, R. E., Jr.↗
Use of a torsional pendulum as a high-pressure gage and determination of viscosity of helium gas at high pressures
Three torsional crystal parameters were examined for suitability in sensing pressure in gases up to 131 million newtons per square meter. The best parameters were found to be the change in crystal decrement at resonance and the change in crystal electrical resistance at resonance. The change in crystal resonant frequency did not appear to be a reliable pressure measuring parameter. Pure argon and pure helium gases were studied for use as working fluids. Helium functioned better over a wider pressure range. Calibration of the gage also provided a measure of the viscosity-density product of the gas as a function of pressure. These data, together with known extrapolated density data, permitted the determination of the viscosity of helium to 131 million N/square meter.
Maisel, J. E.↗