K. C. Fan, W. J. Lin, S. Chen, J. H. Ho
In this research, a low cost high-precision auto-focus laser probe system was developed. Modified from the pickup head of a market available compact disc player as basis, it can detect the Focus Error Signal (FES) of the object with a built-in four-quadrant photodiode. The FES will feedback to the developed controller through which the objective lens can be adjusted to remain in focus using a voice coil motor (VCM). The driving current (converted from Servo FES) of the VCM and objective lens displacement is one to one linearly related within few hundred micrometers. Because of this...
XVI IMEKO World Congress
· 2000
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H. Daßler, L. Thieme, W. Manthey
Micromachined ultrasonic transducer arrays were developed to pan a sound beam electronically in an arbitrary direction. These PVDF-based transducer arrays are suitable for applications in liquids. The characterisation of these transducers is done by acoustical and laseroptical measurements. The single transducer element dimensions varies from 20 to 100 µm for the generated high frequencies up to 20 MHz. The knowledge of the transducer behaviour based on acoustical and laseroptical characterisation of the transducer arrays results in a improved transducer layout. A modified micromechanical...
XVI IMEKO World Congress
· 2000
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D. G. Chetwynd, N. O. Krylova
X-ray interferometers are now a recognized tool for sub-nanometre precision metrology in National Standards Laboratories. Used in slightly different ways, they have potential for wider application as the demands for greater precision in industrial metrology increase. After reviewing some of the key ideas about using monolithic devices in this manner, it is shown that a ‘portable’ system intended for industrial standards rooms can perform well. There is a brief discussion of some issues such as vibration isolation. Details are given of a novel experimental verification that a separated-blade...
XVI IMEKO World Congress
· 2000
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W. Brenner, G. Haddad, A. Vujanic
Two miniaturised torque sensors, based on the cable brake principle and the so-called measurement cross principle, have been developed. The design principles and production process are described. Experimental results show a fair amount of conformity with technical data for minimotors.
XVI IMEKO World Congress
· 2000
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A. Barylski
In this paper there are presented the results of studies of lapping. One of the main disadvantages of lapping is the contamination of machined surfaces with micrograins of the grinding material. This phenomenon is detrimental from the tribological point of view. The micrograins which are embedded into the machined surface during coarse lapping, penetrate during the fine lapping into the abrasive slurry and interfere with the reduction of surface roughness. The abrasion wear of sliding elements is considerably increased during the operation of contaminated parts.
XVI IMEKO World Congress
· 2000
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M. Anwander, B. Weiss, C. Kargel, B. Trummer H. Weiss, B. Zagar
To increase the reliability of microelectronic components it is frequently required to determine mechanical and thermal properties of the base material in its practical dimensions (e.g. thin foils and films, thin wires, membranes). Due to the known "size effect" these material properties cannot be deduced from macro deformation data. In this investigation a non-contacting laser optical strain sensor is being used to determine deformation data of the so called micromaterials in combination with a specially designed microtensile machine. The strain sensor is based on a laser optical speckle...
XVI IMEKO World Congress
· 2000
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Y. Yang, Y. Zhang, J. Gao
The high dose standard and dissemination system of g-rays has already established at NIM. Fricke dosimetry is accepted as primary standard. The transfer standards include alanine/ESR dosimetry and dichromate solution dosimetry. Those dosimeters possess many favorable characteristics, such as good linearity, long shelflife, reproducible and stable radiation response and equivalence to water in terms of radiation absorption properties. In order to guaranteeing the product quality of radiation processing and promoting the progress of radiation techniques. On April 18, 1990, SBTS and SCST had...
XVI IMEKO World Congress
· 2000
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S.Wiese, J. Wichern, W. Kowalsky, W. Grahn
Buildings of reinforced concrete are exposed to a variety of damaging influences. In particular, moisture has an important influence on the lifetime of concrete structures. This is caused by the involvement of free water in corrosion of the steel and the fact that water acts as a transport medium for damaging ions such as chloride, sulfate, carbonate and ammonium. Thus, we have developed fiberoptical moisture sensors, which allow an in-situ non-destructive long-term monitoring of concrete structures. As indicator we use a pyridinium-N-phenolat betain (Reichardt’s dye), which shows a high...
XVI IMEKO World Congress
· 2000
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A. Steinke, B. March, B. Prümm, H. Hansch
Humidity in compressed air is one of the most important problems in industrial and non industrial processes. The compressed air contains humidity despite of the drying process realized by the refrigeration dryer. The reason for that are located in the uncompleted separation process or in leaks along the compressed air pipes. For reasons of the energy and quality management a multiplicity of measurement principles has been developed for this application. But these technical and economical demands require more and more humidity measurement sensors with higher accuracy and long term stability....
XVI IMEKO World Congress
· 2000
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H. Stabinger
A rotary viscometer using an eddy current brake for the measurement of momentum. The instrument covers a range of 0.5 to 30000 mPa·s without changing the measuring cell. The resolution is better than 0.1% and the accuracy 0.2%. A Peltier thermostat controls the measuring temperature from -20°C to 100°C with 0.01°C accuracy. Fast response and a short measuring time are the benefits of this instrument.
XVI IMEKO World Congress
· 2000
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