A TUBULAR CAPACITOR OF STABLE VALUE

1964 ◽  
Vol 42 (8) ◽  
pp. 1508-1521 ◽  
Author(s):  
M. Kanno
Keyword(s):  
Temperature Coefficient ◽  
High Precision ◽  
International Comparisons ◽  
Free Fall ◽  
Precision Measurements ◽  
Mechanical Assembly ◽  
Voltage Coefficient ◽  
Fused Quartz ◽  
Recent Developments ◽  
Very High

Very high precision measurements of capacitance have been achieved by recent developments of transformer bridge techniques. Reference capacitors for use with these bridges must be very stable with time and temperature, as well as having other superior characteristics, all of which are very difficult to achieve with the usual mechanical assembly of conductors.This new capacitor uses fused quartz or pyrex glass tubing simply as a support for deposited metallic electrodes, and results in capacitance values of 1 pF which are stable to within one part per million (p.p.m.) for at least six months. They have a temperature coefficient of less than 3 p.p.m./°C, a voltage coefficient of less than 1 p.p.m. for applied voltages from 10 volts to 100 volts, and stability of 1 p.p.m. after free-fall drops from 10-cm heights.It is anticipated that a capacitor of this style will prove to be very useful as a transportable standard of capacitance, and could be used in international comparisons of capacitance values.

Cold atom interferometry for inertial sensing in the field

2020 ◽  
Vol 9 (5) ◽  
pp. 221-225
Author(s):  
Ravi Kumar ◽  
Ana Rakonjac
Keyword(s):  
High Precision ◽  
Cold Atoms ◽  
Cold Atom ◽  
Atom Interferometry ◽  
Precision Measurements ◽  
Inertial Sensing ◽  
Fundamental Physics ◽  
Recent Developments ◽  
Resource Exploration ◽  
Atom Interferometers

AbstractAtom interferometry is one of the most promising technologies for high precision measurements. It has the potential to revolutionise many different sectors, such as navigation and positioning, resource exploration, geophysical studies, and fundamental physics. After decades of research in the field of cold atoms, the technology has reached a stage where commercialisation of cold atom interferometers has become possible. This article describes recent developments, challenges, and prospects for quantum sensors for inertial sensing based on cold atom interferometry techniques.

A Compound Recoil-Compensated Chamber Design for Free-Fall Absolute Gravimeters

2020 ◽  
Author(s):  
Yi Wen ◽  
Kang Wu ◽  
Meiying Guo ◽  
Lijun Wang
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Test Mass ◽  
Precision Measurements ◽  
Gravity Measurement ◽  
Absolute Gravity ◽  
Systematic Bias ◽  
Chamber Design ◽  
Measurement Results ◽  
Gravity Measurements

Abstract The ballistic free-fall absolute gravimeters are most commonly-used instruments for high-precision absolute gravity measurements in many fields, such as scientific research, resource survey, geophysics and so on. The instrumental recoil vibrations generated by the release of the test mass can cause troublesome systematic bias, because these vibrations are highly reproducible from drop to drop with coherent phase. A compound counterbalanced design of chamber using both belt-driven mechanism and cam-driven structure is proposed in this paper. This structure is designed to achieve excellent recoil compensation as well as long freefall length for high precision measurements. Simulation results show that the recoil vibration amplitude of the compound recoil-compensated structure during the drop is about 1/4 of that with only belt-driven counterbalanced structure. This confirms the feasibility and superiority of the new design. And it is believed that the absolute gravimeter based on this newly proposed chamber design is expected to obtain more precise gravity measurement results in the future.

Synchronised Low-Frequency Augmentation of GPS (SYLFA)

1998 ◽  
Vol 51 (3) ◽  
pp. 294-303
Author(s):  
William F. Roland
Keyword(s):  
Data Compression ◽  
High Precision ◽  
New Technologies ◽  
Low Cost ◽  
Low Frequency ◽  
Wide Area ◽  
Signal Modulation ◽  
Modulation Techniques ◽  
Recent Developments ◽  
Very High

As new technologies contribute to the expanded functionality of Loran-C, and as concerns for limitations in GPS and its augmentations are raised, specific aspects of Loran-C have been developed and applied to ameliorate those limitations. Specifically, GPS availability is a concern, particularly in over-land applications. This paper discusses recent developments using very high-precision synchronisation of Loran-C transmissions, new data compression and Loran-C signal modulation techniques to augment GPS accuracy, availability and integrity over a very wide area at very low cost.

State special primary acceleration measurement standard for gravimetry GET 190-2019

2020 ◽  
pp. 3-8
Author(s):  
L.F. Vitushkin ◽  
F.F. Karpeshin ◽  
E.P. Krivtsov ◽  
P.P. Krolitsky ◽  
V.V. Nalivaev ◽  
...  
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Measurement Range ◽  
Measurement Standard ◽  
Acceleration Measurement ◽  
Measurement Systems ◽  
Free Fall Acceleration ◽  
Investigation Methods ◽  
Measurement Results ◽  
Upper Level

The State special primary acceleration measurement standard for gravimetry (GET 190-2019), its composition, principle of operation and basic metrological characteristics are presented. This standard is on the upper level of reference for free-fall acceleration measurements. Its accuracy and reliability were improved as a result of optimisation of the adjustment procedures for measurement systems and its integration within the upgraded systems, units and modern hardware components. A special attention was given to adjusting the corrections applied to measurement results with respect to procedural, physical and technical limitations. The used investigation methods made it possibled to confirm the measurement range of GET 190-2019 and to determine the contributions of main sources of errors and the total value of these errors. The measurement characteristics and GET 90-2019 were confirmed by the results obtained from measurements of the absolute value of the free fall acceleration at the gravimetrical site “Lomonosov-1” and by their collation with the data of different dates obtained from measurements by high-precision foreign and domestic gravimeters. Topicality of such measurements ensues from the requirements to handle the applied problems that need data on parameters of the Earth gravitational field, to be adequately faced. Geophysics and navigation are the main fields of application for high-precision measurements in this field.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals Equipartition principle for Wigner matrices

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhigang Bao ◽  
László Erdős ◽  
Kevin Schnelli
Keyword(s):  
High Precision ◽  
Quantum Systems ◽  
Wigner Matrices ◽  
Very High

Abstract We prove that the energy of any eigenvector of a sum of several independent large Wigner matrices is equally distributed among these matrices with very high precision. This shows a particularly strong microcanonical form of the equipartition principle for quantum systems whose components are modelled by Wigner matrices.

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