scholarly journals A Practical Positioning Method in End-Plate Surface Distance Measurement with Nano-Meter Precision

2019 ◽  
Vol 9 (22) ◽  
pp. 4970
Author(s):  
Hongtang Gao ◽  
Zhongyu Wang ◽  
Yinbao Cheng ◽  
Yaru Li ◽  
Shuanghua Sun ◽  
...  
Keyword(s):  
Practical Method ◽  
Standard Uncertainty ◽  
Experimental Result ◽  
Plate Surface ◽  
Surface Distance ◽  
End Plate ◽  
Light Interference ◽  
Positioning Method ◽  
Height Step ◽  
Signal Processing Methods

End-plate surface distance is important for length value dissemination in the field of metrology. For the measurement of distance of two surfaces, the positioning method is the key for realizing high precision. A practical method with nanometer positioning precision is introduced in consideration of the complexity of positioning laser sources of the traditional methods and new methods. The surface positioning is realized by the combination of laser interference and white light interference. In order to verify the method, a 0.1 mm height step is made, and an experiment system based on the method is established. The principle and the basic theory of the method are analyzed, and the measures to enhance the repeatability from optical and mechanical factors and signal processing methods are presented. The experimental result shows that the surface positioning repeatability is in the order of 10 nm. The measurement uncertainty evaluation shows that the standard uncertainty is 21 nm for a 0.1 mm step. It is concluded that the method is suitable to be applied to the length measurement standard of the lab.

scholarly journals COMPONENT METHOD EXTENSION TO STEEL BEAM‐TO‐BEAM AND BEAM‐TO‐COLUMN KNEE JOINTS UNDER BENDING AND AXIAL FORCES

2005 ◽  
Vol 11 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Kestutis Urbonas ◽  
Alfonsas Daniūnas
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Practical Method ◽  
Knee Joints ◽  
Steel Beam ◽  
Component Method ◽  
End Plate ◽  
Axial Forces ◽  
Joint Rigidity

This paper presents an analysis of semi‐rigid beam‐to‐beam end‐plate bolted and beam‐to‐column end‐plate bolted knee joints that are subjected to bending and tension or compression axial force. Usually the influence of axial force on joint rigidity is neglected. According to EC3, the axial load, which is less than 10 % of plastic resistance of the connected member under axial force, may be disregarded in the design of joint. Actually the level of axial forces in joints of structures may be significant and has a significant influence on joint rigidity. One of the most popular practical method permitting the determination of rigidity and strength of joint is the so‐called component method. The extension of the component method for evaluating the influence of bending moment and axial force on the rigidity and strength of the joint are presented in the paper. The numerical results of calculations of rigidity and strength of beam-to-beam and beam-to-column knee joints are presented in this paper as well.

Performance Study for T-Stub Considering the Bending Capacity of Bolt

2015 ◽  
Vol 741 ◽  
pp. 175-178
Author(s):  
Shi Zhe Chen ◽  
Zhan Wang ◽  
Chao Zhou
Keyword(s):  
Stress Distribution ◽  
Tensile Property ◽  
Monotonic Loading ◽  
Experimental Result ◽  
Deformation Characteristics ◽  
Performance Study ◽  
Loading Test ◽  
End Plate ◽  
Calculation Results ◽  
Bending Capacity

The bending capacity of the beam end-plate or the column flange and the tensile property of the bolt could be expressed by an equivalent t-stub model. In this paper, ten groups of different sizes of T-stub are designed for monotonic loading test. The accurate element models are established for comparable study with the experimental result. The stress distribution and deformation characteristics of the T-stub and bolts are determined. A theoretic formula of tensile stiffness for T-stub is derived, it is presented that the calculation results are consistent with the tests.

scholarly journals Application of a Vision-Based Single Target on Robot Positioning System

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1829
Author(s):  
Jing Yu ◽  
Wensong Jiang ◽  
Zai Luo ◽  
Li Yang
Keyword(s):  
Image Matching ◽  
Circular Ring ◽  
Fiducial Marker ◽  
Experimental Result ◽  
Long Distance ◽  
Translation Error ◽  
Single Target ◽  
Robot Positioning ◽  
Positioning Method ◽  
Average Rotation

In this paper, we propose a Circular-ring visual location marker based on a global image-matching model to improve the positioning ability in the fiducial marker system of a single-target mobile robot. The unique coding information is designed according to the cross-ratio invariance of the projective theorem. To verify the accuracy of full 6D pose estimation using the Circular-ring marker, a 6 degree of freedom (DoF) robotic arm platform is used to design a visual location experiment. The experimental result shows in terms of small resolution images, different size markers, and long-distance tests that our proposed robot positioning method significantly outperforms AprilTag, ArUco, and Checkerboard. Furthermore, through a repeatable robot positioning experiment, the results indicated that the proposed Circular-ring marker is twice as accurate as the fiducial marker at 2–4 m. In terms of recognition speed, the Circular-ring marker processes a frame within 0.077 s. When the Circular-ring marker is used for robot positioning at 2–4 m, the maximum average translation error of the Circular-ring marker is 2.19, 3.04, and 9.44 mm. The maximum average rotation error is also 1.703°, 1.468°, and 0.782°.

Algorithm Study for Metal Magnetic Memory Signal Processing

2012 ◽  
Author(s):  
Zhanjun Feng ◽  
Weibin Wang ◽  
Hongjun Dong ◽  
Song Lin ◽  
Dianxue Wang ◽  
...  
Keyword(s):  
Signal Processing ◽  
Real Data ◽  
Experimental Result ◽  
Work Piece ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Destructive Testing ◽  
Singularity Detection ◽  
Signal Processing Methods ◽  
Non Destructive

Currently, Metal Magnetic Memory (MMM) non-destructive testing has been applied on trenchless inspection for buried pipeline. However, the problem of signal pattern recognition still exists. This paper introduces two signal processing methods to enhance the inspection accuracy of MMM: the signal segmented fluctuation and the signal segmented dissimilarity. Both of the two methods are designed for Signal singularity detection (SSD) of MMM signal. It is well known that the MMM signal of the stress concentrated area (SCA) is more fluctuant and dissimilar in contrast to those of non SCA, which is the basis of deriving the two algorithms. The two methods have the advantage in the detection of the metallic work piece which is non defective in looks but fatigued as well as may be helpful to detect the singularity of the signals such as negative pressure wave, ultrasonic wave etc. Experimental result with real data demonstrates the effectiveness of the proposed algorithms. Moreover, the MMM SSD software implementation is considered.

Theoretical Study on Similarity Relation of Small Scale Subgrade Shaking Table Test Model

2011 ◽  
Vol 255-260 ◽  
pp. 3354-3360 ◽  
Author(s):  
Jin Bei Li ◽  
Hong Ru Zhang ◽  
Zhi Qiang Li
Keyword(s):  
Theoretical Calculation ◽  
Calculation Result ◽  
Shaking Table Test ◽  
Similarity Theory ◽  
Practical Method ◽  
Shaking Table ◽  
Similarity Relation ◽  
Experimental Result ◽  
Small Scale ◽  
Test Model

Shaking table test is an important method to study seismic performance of geotechnical structures. Processing the similarity relation and deducing the response of original mold correctly are very important. Based on similarity theory, the paper adopts a dimensional analysis method to solve almost all similar constants, and provides a practical method on designing subgrade model of shaking table test. During the model designing process, several basic similar constants are defined at first and other main similar constants are obtained according to the basic similar constants. This method is applied in practical earthquake simulated shaking table test. Partial results are compared with the theoretical calculation result. The experimental result which is in concordance to the theoretical calculation result can reflect the seismic response rules of subgrade correctly. So the practical designing method is feasible.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

Determination of arsenic atom distribution arsenic doped silicon using HOLZ-line analysis

1996 ◽  
Vol 54 ◽  
pp. 976-977
Author(s):  
Y. Kikuchi ◽  
N. Hashikawa ◽  
F. Uesugi ◽  
E. Wakai ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Zone Axis ◽  
Experimental Result ◽  
Background Intensity ◽  
Crystal Thickness ◽  
Arsenic Atom ◽  
Doped Silicon ◽  
P Type ◽  
Line Analysis

In order to measure the concentration of arsenic atoms in nanometer regions of arsenic doped silicon, the HOLZ analysis is carried out underthe exact [011] zone axis observation. In previous papers, it is revealed that the position of two bright lines in the outer SOLZ structures on the[011] zone axis is little influenced by the crystal thickness and the background intensity caused by inelastic scattering electrons, but is sensitive to the concentration of As atoms substitutbnal for Siatomic site.As the result, it becomes possible to determine the concentration of electrically activated As atoms in silicon within an observed area by means of the simple fitting between experimental result and dynamical simulatioan. In the present work, in order to investigate the distribution of electrically activated As in silicon, the outer HOLZ analysis is applied using a nanometer sized probe of TEM equipped with a FEG.Czodiralsld-gown<100>orientated p-type Si wafers with a resistivity of 10 Ώ cm are used for the experiments.TheAs+ implantation is performed at a dose of 5.0X1015cm-2at 25keV.

Scoring concepts maps: Can a practical method of scoring concept maps be used to assess trainee's knowledge structures?

2004 ◽  
Author(s):  
Michelle E. Harper ◽  
Raegan M. Hoeft ◽  
A. W. Evans ◽  
Florian G. Jentsch
Keyword(s):  
Concept Maps ◽  
Practical Method ◽  
Knowledge Structures

Practical Method of Counterfeiting Antique Silver

1903 ◽  
Vol 56 (1452supp) ◽  
pp. 23267-23267
Keyword(s):  
Practical Method
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