A NEW SCHEME TO REALIZE THE MEASUREMENT STANDARD OF MICROFORCE

2005 ◽  
Vol 04 (04) ◽  
pp. 689-694
Author(s):  
HSIEN-CHI YEH ◽  
SWEE HOCK YEO ◽  
SHEAU-SHI PAN ◽  
JUN LUO

To increase the accuracy of mechanical characterizations of microstructures and nanomaterials on the molecular- and nano-scale, the measurement standard of microforce ranging from 10-6 N to 10-9 N must be realized for calibrating the testing and measuring instruments. In this paper, a new scheme based on the equal-arm torsion balance is proposed. This precision torsion balance detects accurately the gravitational force between two mass standards, and links the small force measurement to the International System of Units and Newtonian gravitational constant G. Such a balance might serve as a force standard machine operating in the regime below 10-6 N with an accuracy of 0.1%.

2007 ◽  
Vol 22 (29) ◽  
pp. 5391-5400
Author(s):  
M. ROSSI ◽  
L. ZANINETTI

The Newtonian gravitational constant has still 150 parts per million of uncertainty. This paper examines the linear and nonlinear equations governing the rotational dynamics of the torsion gravitational balance. A nonlinear effect modifying the oscillation period of the torsion gravitational balance is carefully explored.


2020 ◽  
Vol 42 (4) ◽  
pp. 5-18
Author(s):  
V.P. Babak ◽  
A.A. Zaporozhets ◽  
Y.V. Kuts ◽  
L.M. Scherbak

It is known that deterministic and probabilistic models of measured quantities, processes and fields, as well as physical and probabilistic measures, make it possible to form a measurement result, to provide it with the properties of objectivity and reliability. On their basis, the measuring instruments necessary for obtaining new knowledge and maintaining the process of technological development of production are being developed and improved. Therefore, the issues of improving and developing models and measures in measurement methodology play an increasingly important role in achieving high measurement accuracy and expanding the areas of their application. The article is devoted to the features and results of the study of the application of models and measures in measurements. It is shown that the physical correctness and the need for setting up measuring experiments, performing tasks and conditions for their implementation, substantiating adequate models and measures significantly affect the obtained measurement result. The features of the modern methodology of using models of signals and fields and measures for evaluating the results of measuring physical quantities, including thermophysical ones, which are represented by random quantities and angles are presented. In the general case, a measure is a countably additive set function that acquires only negative values ​​in any way, including infinity. The use of charge as a mathematical model significantly expands the boundaries of the practical application of the methods of measure theory in metrology. Examples of probabilistic measures on a straight line, on a circle and a charge, as well as physical measures are considered. The concept of coordination of physical and probabilistic measures has been substantiated with the aim of a unified approach to assessing the measurement result. The joint use of physical and probabilistic measures for the formation of a measurement result allows to a certain extent overcome the problem of measurement homomorphism. An example of using a set of physical and probabilistic measures in the hardware and software modules of information and measuring systems is given. The probabilistic normalized measure is a non-physical degree, but a measure of the totality of the action of various random factors on the value and characteristics of data and the result of measurements when they are carried out. The use of a probabilistic measure in the statistical processing of measurement data makes it possible to increase the accuracy of the measurement result compared to the accuracy of the measurement data. The degree of information protection during measurements is complex. The measure is formed by many factors, the action of most of which is of a random nature. This makes it possible to determine such a measure as probabilistic, which can be applied both for individual operations, for example, transmission of measurement data via communication channels, registration of the measurement result, and for the entire measurement process as a whole. The stochastic approach in the theory of measurements is of particular importance in the case of measurements of physical quantities that have a pronounced probabilistic nature, for example, in the case of nano-measurements, the study of quantum effects, and the like. Currently, the use of the SI international system of units at the quantum level and the concept of uncertainty for evaluating measurement results, which are the foundation of measurement practice, requires a wide range of theoretical and simulation studies of measurement processes in various subject areas to form a unified measurement methodology.


ACTA IMEKO ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 4 ◽  
Author(s):  
Jile Jiang ◽  
Gang Hu ◽  
Zhimin Zhang

<p><span lang="EN-US">A small force of (10</span><span lang="EN-US">–</span><span lang="EN-US">100) micro-Newton traceable to the International System of Units (SI) has been realized using</span><span lang="EN-US"> an</span><span lang="EN-US"> electrostatic </span><span lang="EN-US">measuring system</span><span lang="EN-US"> at the National Institute of Metrology, China. The key component of the measuring system is a pair of coaxial cylindrical electrodes. The inner electrode is suspended with the support of a self-balanced flexure hinge, while the outer electrode is attached to a piezoelectric moving stage. The stiffness of the self-balanced flexure hinge was also designed so as to be both sufficiently stable and sensitive to the small force applied to the inner electrode. Two sets of cameras were </span><span lang="EN-US">used</span><span lang="EN-US"> to capture the shape of the electrodes and to obtain a better coaxial arrangement of the inner and outer electrodes. With the help of a capacitance bridge and a piezoelectric moving stage, the relative standard uncertainty of the capacitance gradient does not exceed 0.04 %. Associated with a laser interferometer and a DC voltage power source, the feedback system that controls the position of the inner electrode is responsible for the generation of a force of 10–100 micro-Newton. The standard uncertainty associated with the force of 100 micro-Newton does not exceed 0.1 %.</span></p>


2020 ◽  
pp. 26-32
Author(s):  
M. I. Kalinin ◽  
L. K. Isaev ◽  
F. V. Bulygin

The situation that has developed in the International System of Units (SI) as a result of adopting the recommendation of the International Committee of Weights and Measures (CIPM) in 1980, which proposed to consider plane and solid angles as dimensionless derived quantities, is analyzed. It is shown that the basis for such a solution was a misunderstanding of the mathematical formula relating the arc length of a circle with its radius and corresponding central angle, as well as of the expansions of trigonometric functions in series. From the analysis presented in the article, it follows that a plane angle does not depend on any of the SI quantities and should be assigned to the base quantities, and its unit, the radian, should be added to the base SI units. A solid angle, in this case, turns out to be a derived quantity of a plane angle. Its unit, the steradian, is a coherent derived unit equal to the square radian.


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