Study of a laser gyroscope using the Allan variation method

Author(s):  
A.S. Bolotnov ◽  
◽  
I.I. Fomin ◽  
2013 ◽  
Vol 24 ◽  
pp. 1360039 ◽  
Author(s):  
YU-SHAN YEH ◽  
SHENG-JUI CHEN ◽  
CHIN-FEN TUAN ◽  
YI-CHING LIN ◽  
SHEAU-SHI PAN

Specifying and reducing the uncertainty is very important to all kinds of measurements. In order to have a better understanding of the noise mechanism responsible for lowering the quality of mass/force measurements, the Allan variation method is applied to investigate the noise performance of a commercial ultra-microbalance installed on different noise reduction platforms. It turns out that the marble table provides a better noise isolation environment for mass measurements than an optical table. The optimal integration time is found to be 100 sec ~ 200 sec, with a lowest deviation of 0.07 μg. A different data treatment simulating the ABA load/unload cycle is also applied with or without a delay time for signal integration. The consistency between Allan deviation and the ABA simulation plots points out that the optimal integration time is applicable either in single or cyclic mass measurements.


Author(s):  
W.J. de Ruijter ◽  
M.R. McCartney ◽  
David J. Smith ◽  
J.K. Weiss

Further advances in resolution enhancement of transmission electron microscopes can be expected from digital processing of image data recorded with slow-scan CCD cameras. Image recording with these new cameras is essential because of their high sensitivity, extreme linearity and negligible geometric distortion. Furthermore, digital image acquisition allows for on-line processing which yields virtually immediate reconstruction results. At present, the most promising techniques for exit-surface wave reconstruction are electron holography and the recently proposed focal variation method. The latter method is based on image processing applied to a series of images recorded at equally spaced defocus.Exit-surface wave reconstruction using the focal variation method as proposed by Van Dyck and Op de Beeck proceeds in two stages. First, the complex image wave is retrieved by data extraction from a parabola situated in three-dimensional Fourier space. Then the objective lens spherical aberration, astigmatism and defocus are corrected by simply dividing the image wave by the wave aberration function calculated with the appropriate objective lens aberration coefficients which yields the exit-surface wave.


1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1251-C8-1252
Author(s):  
W. Brauneck ◽  
O. Jagodzinski ◽  
D. Wagner

The methods by which neutron diffraction and inelastic scattering may be used to study the structure and dynamics of solutions are reviewed, with particular reference to solutions of amphiphile and biological molecules in water. Neutron methods have particular power because the scattering lengths for protons and deuterons are of opposite sign, and hence there exists the possibility of obtaining variable contrast between the scattering of the aqueous medium and the molecules in it. In addition, the contrast variation method is also applicable to inelastic scattering studies whereby the dynamics of one component of the solution can be preferentially studied due to large and variable differences in the scattering cross sections. Both applications of contrast variation are illustrated with examples of amphiphile-water lamellar mesophases, diffraction from collagen, viruses, and polymer solutions. Inelastic scattering observations and the dynamics of water between the lamellar sheets allow microscopic measurements of the water diffusion along and perpendicular to the layers. The information obtained is complementary to that from nuclear magnetic resonance and electron spin resonance studies of diffusion.


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