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  • Instrumentation and Photography  (8)
  • Life and Medical Sciences
  • Mexico
  • Sarcoplasmic reticulum
  • 2000-2004  (8)
Collection
Keywords
Years
Year
  • 1
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    Unknown
    Pulsed-Source Interferometry in Acoustic Imaging (2003)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A combination of pulsed-source interferometry and acoustic diffraction has been proposed for use in imaging subsurface microscopic defects and other features in such diverse objects as integrated-circuit chips, specimens of materials, and mechanical parts. A specimen to be inspected by this technique would be mounted with its bottom side in contact with an acoustic transducer driven by a continuous-wave acoustic signal at a suitable frequency, which could be as low as a megahertz or as high as a few hundred gigahertz. The top side of the specimen would be coupled to an object that would have a flat (when not vibrating) top surface and that would serve as the acoustical analog of an optical medium (in effect, an acoustical "optic").
    Keywords: Instrumentation and Photography
    Type: NPO-20478 , NASA Tech Briefs, March 2003; 19
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Silicon base plate with low parasitic electrical interference for sensors (2002)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: A microgyroscope has a baseplate made of the same material as the rest of the microgyroscope. The baseplate is a silicon baseplate having a heavily p-doped epilayer covered by a thick dielectric film and metal electrodes. The metal electrodes are isolated from the ground plane by the dielectric. This provides very low parasitic capacitive coupling between the electrodes. The thick dielectric reduces the capacitance between the electrodes and the ground plane.
    Keywords: Instrumentation and Photography
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    NASA TECHNICAL REPORTS
  • 3
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    High Resolution and Large Dynamic Range Resonant Pressure Sensor Based on Q-Factor Measurement (2000)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A pressure sensor has a high degree of accuracy over a wide range of pressures. Using a pressure sensor relying upon resonant oscillations to determine pressure, a driving circuit drives such a pressure sensor at resonance and tracks resonant frequency and amplitude shifts with changes in pressure. Pressure changes affect the Q-factor of the resonating portion of the pressure sensor. Such Q-factor changes are detected by the driving/sensing circuit which in turn tracks the changes in resonant frequency to maintain the pressure sensor at resonance. Changes in the Q-factor are reflected in changes of amplitude of the resonating pressure sensor. In response, upon sensing the changes in the amplitude, the driving circuit changes the force or strength of the electrostatic driving signal to maintain the resonator at constant amplitude. The amplitude of the driving signals become a direct measure of the changes in pressure as the operating characteristics of the resonator give rise to a linear response curve for the amplitude of the driving signal. Pressure change resolution is on the order of 10(exp -6) torr over a range spanning from 7,600 torr to 10(exp -6) torr. No temperature compensation for the pressure sensor of the present invention is foreseen. Power requirements for the pressure sensor are generally minimal due to the low-loss mechanical design of the resonating pressure sensor and the simple control electronics.
    Keywords: Instrumentation and Photography
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  • 4
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    Dual beam optical interferometer (2003)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: A dual beam interferometer device is disclosed that enables moving an optics module in a direction, which changes the path lengths of two beams of light. The two beams reflect off a surface of an object and generate different speckle patterns detected by an element, such as a camera. The camera detects a characteristic of the surface.
    Keywords: Instrumentation and Photography
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    NASA TECHNICAL REPORTS
  • 5
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    Unknown
    Inertial sensor and method of use (2003)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: The inertial sensor of the present invention utilizes a proof mass suspended from spring structures forming a nearly degenerate resonant structure into which a perturbation is introduced, causing a split in frequency of the two modes so that the mode shape become uniquely defined, and to the first order, remains orthogonal. The resonator is provided with a mass or inertia tensor with off-diagonal elements. These off-diagonal elements are large enough to change the mode shape of the two nearly degenerate modes from the original coordinate frame. The spring tensor is then provided with a compensating off-diagonal element, such that the mode shape is again defined in the original coordinate frame. The compensating off-diagonal element in the spring tensor is provided by a biasing voltage that softens certain elements in the spring tensor. Acceleration disturbs the compensation and the mode shape again changes from the original coordinate frame. By measuring the change in the mode shape, the acceleration is measured.
    Keywords: Instrumentation and Photography
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  • 6
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    Unknown
    Microgyroscope with integrated vibratory element (2002)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: A microgyroscope having a suspended vertical post uses the Coriolis force to detect the rotation rate. The microgyroscope consists of a single vertical post which is the rotation rate sensing element. The vertical post is formed from the same silicon wafers as the rest of the microgyroscope. A first portion of the vertical post and the clover-leaf structure are made from a first silicon wafer. A second portion of the vertical post and the baseplate are made from a second silicon wafer. The two portions are then bonded together to from the clover-leaf gyroscope with an integrated post structure.
    Keywords: Instrumentation and Photography
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  • 7
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    Unknown
    Microgyroscope with closed loop output (2002)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.
    Keywords: Instrumentation and Photography
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  • 8
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    Unknown
    Non-inertial calibration of vibratory gyroscopes (2003)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: The electrostatic elements already present in a vibratory gyroscope are used to simulate the Coriolis forces. An artificial electrostatic rotation signal is added to the closed-loop force rebalance system. Because the Coriolis force is at the same frequency as the artificial electrostatic force, the simulated force may be introduced into the system to perform an inertial test on MEMS vibratory gyroscopes without the use of a rotation table.
    Keywords: Instrumentation and Photography
    Format: application/pdf
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