An Application of the Fractal Theory in the Design of Heat Sink for Precision Measurement Instrument

Author(s):  
S.R. Lee ◽  
Z.G. Li ◽  
B.G. Wang ◽  
H.S. Chiou
2005 ◽  
Vol 295-296 ◽  
pp. 717-722 ◽  
Author(s):  
S.R. Lee ◽  
Z.G. Li ◽  
B.G. Wang ◽  
H.S. Chiou

Temperature variation on accuracy and stability in measurement instruments is an important issue. High performance and miniaturized instruments have rigorous requirements on temperature. Heat transfer and temperature control are important in instruments design. For laser interferometer, temperature variation will adversely affect the frequency stability of the laser and the measuring precision. In order to effectively stabilize the frequency, a simple and effective heat sink design for laser interferometer is presented. It is based on the fractal theory and the heat transfer characteristics to allow higher dissipation for temperature control to generate higher heat transfer area in a finite space. Experimental results in frequency stabilization clearly show that this method is effective.


2021 ◽  
Vol 15 (4) ◽  
pp. 537-545
Author(s):  
Kazuhide Tanaka ◽  
◽  
Dan Nakaya ◽  
Yuki Kondo ◽  
Ichiro Yoshida

In electric power stations, precision surface roughness measurements are performed for environmental loading reduction, quality assurance, and safety. These measurements are performed manually at high places, narrow places, uncomfortable environments, etc. Therefore, workers in power stations experience a lot of hardship and are exposed to danger. To solve these issues, this study researched and developed a crawler-type robot with high measurement accuracy. Conventionally, robots that supply workpieces for surface roughness instruments have been developed. However, to the best of our knowledge, robotization and self-propelled precision measurement instruments have not been developed. Usually, a precision measurement instrument is designed for increased stiffness and stability because high measurement accuracy is the highest priority. However, if the stiffness and stability of the robot are as high as those of the precision measurement instrument, a problem occurs in the robot operation. Therefore, we propose a precision measurement unit using electromagnets and a crawler-type self-propelled robot to equip the unit. In a previous study, vibration analysis experiments using the impulse response method were performed on a precision measuring robot. In this study, the relationships between the voltages applied to the electromagnet and the reductions in the vibration magnitudes were determined by analyzing the vibrations of the robot during measurement. Furthermore, an optimal voltage of the electromagnets of the precision measuring robot to reduce vibrations was determined. From the results of the vibration analysis, the authors demonstrated that the optimal voltages were 9 and 12 V, and the precision measurement unit confirmed the effectiveness and validity of vibration reduction and improved measurement accuracy.


Author(s):  
Zhenyuan Jia ◽  
Lei Jin ◽  
Wei Liu ◽  
Zongjin Ren

Piezoelectric force sensors are widely used in precision measurement and machining applications. Sensitivity is one of the significant parameters determining the precision of these sensors. The influence of factors, such as the piezoelectric coefficient, sensor structure, and temperature on sensitivity had previously been studied except the roughness of sheets. For design optimization, the effect of roughness on the sensitivity of piezoelectric force sensors was investigated. A sensitivity model was built based on the electromechanical relationships and measurement systems. Fractal theory and classic statistics model were used to define the roughness of the sheets. The stiffness effect and thickness effect were used to probe the relationship, and two types of experiments with sheets of different roughness were performed to verify the models. The results indicated that the roughness of the sheets affected the sensitivity of the piezoelectric dynamometers due to the stiffness effect and thickness effect. In terms of the thickness effect, rough sheets induced high sensitivity; however, in terms of the stiffness effect, as the roughness decreases, the sensitivity first improved and then decreased. A method was proposed to optimize the roughness of the sheets to improve the sensor performance.


Author(s):  
Matthew R. Libera ◽  
Martin Chen

Phase-change erasable optical storage is based on the ability to switch a micron-sized region of a thin film between the crystalline and amorphous states using a diffraction-limited laser as a heat source. A bit of information can be represented as an amorphous spot on a crystalline background, and the two states can be optically identified by their different reflectivities. In a typical multilayer thin-film structure the active (storage) layer is sandwiched between one or more dielectric layers. The dielectric layers provide physical containment and act as a heat sink. A viable phase-change medium must be able to quench to the glassy phase after melting, and this requires proper tailoring of the thermal properties of the multilayer film. The present research studies one particular multilayer structure and shows the effect of an additional aluminum layer on the glass-forming ability.


2007 ◽  
Author(s):  
Tristan E. Johnson ◽  
Youngmin Lee ◽  
Miyoung Lee ◽  
Debra L. O'Connor ◽  
Mohammed K. Khalil ◽  
...  

1991 ◽  
Vol 1 (12) ◽  
pp. 1669-1673 ◽  
Author(s):  
Hans Gerd Evertz ◽  
Martin Hasenbusch ◽  
Mihail Marcu ◽  
Klaus Pinn ◽  
Sorin Solomon

2011 ◽  
Vol 1 (9) ◽  
pp. 65-67
Author(s):  
Pritesh S Patel ◽  
◽  
Prof. Dattatraya G Subhedar ◽  
Prof. Kamlesh V Chauhan

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