scholarly journals Performance Analysis of Low-Gain Feedback for Saturated Differential Drag in a High-precision Orbit Propagator

2020 ◽  
Vol 63 (5) ◽  
pp. 243-247
Author(s):  
Mohamed SHOUMAN ◽  
Mai BANDO ◽  
Shinji HOKAMOTO
Keyword(s):  
Performance Analysis ◽  
High Precision ◽  
Differential Drag

Performance Analysis of Two Robots one Serial 4R and one Parallel 3T

2015 ◽  
Vol 762 ◽  
pp. 137-146
Author(s):  
Constantin Ocnărescu
Keyword(s):  
Performance Analysis ◽  
High Precision ◽  
Parallel Manipulator ◽  
Machine Building ◽  
Degree Of Freedom ◽  
Building Industry ◽  
Attractive Alternative ◽  
Kinematic Study ◽  
Structural Solution

A geometric and kinematic study between two structures of robots was performed, respectively a mechanical anthropomorphic structure, with bars and gears, with four degree of freedom, (dof), redundant (4R), which can avoid obstacles and a parallel manipulator with translation on three axes (3T). This 3T structural solution allows rapid and precise movements, which are important characteristics for machine building industry. All these features make the parallel manipulator to be an attractive alternative to the serial ones for high precision operations in a limited workspace.

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

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