• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.10a
• /
• pp.198-203
• /
• 1998

To acquire the high precision of profile for standard electrode of loss angle, it is needed ultraprecision machining technology like MEAP(Magnetic Electronic Abrasive Polishing) and the very high profile measurement technology which can measure a micro unit about the workpiece. So, in this paper, it was developed the measurement system of precision of profile using non-contactable sensor that was approximate sensor of capacitance type, because that is better than others in the electrical characteristics. And standard electrode of loss angle was machined by the MEAP machining technology. In this study, it was development of precision measurement system. This system could be used measure the workpiece of roundness and straightness much more precise and faster than general mechanical measurement system done before. And it could be helped to minimize machining time and planning by very fast and precise measurement about the workpiece.

• Journal of Sensor Science and Technology
• /
• v.10 no.4
• /
• pp.259-265
• /
• 2001

FET-type dissolved oxygen sensor has the Pt working electrode around the pH-ISFET. Appling a voltage to the working electrode, the hydrogen ion which is proportional to the dissolved oxygen concentration occurs around the pH sensing gate and we can measure the dissolved oxygen concentration by detecting pH concentration through the pH-ISFET. In this paper, a dissolved oxygen measurement system using FET-type dissolved oxygen sensor array which adopt a specific algorithm to enhance the reliability has been developed and we compared its performance with the commercial dissolved oxygen measurement system.

• Journal of the Korean Applied Science and Technology
• /
• v.24 no.4
• /
• pp.377-382
• /
• 2007

We designed capacitance sensor in order to examine characteristics of W/O type emulsified fuel, so it concluded the following conclusions. The capacitance value of emulsified fuel, using with capacitance sensor, increases as water content increases due to the coalescence. When surfactant increases, the capacitance value decreases, the condition of W/O type emulsified fuel was maintained stably. There was revealed the capacitance value difference of W/O type emulsified fuel in in according to water content. We checked the phase separation of emulsified fuel with the capacitance value difference. The surfactant(HLB=5.4) had better stable condition than surfactant(HLB=4.3). Also, we confirmed that two mixture surfactants were better than one surfactant.

• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.3
• /
• pp.382-388
• /
• 2002

Dissolved silica is one of fatal components at a boiler facility Therefore, a dissolved silica measurement system should be equipped for managing efficiently the boiler facility. Most of silica measurement systems are composed of a sensor module of single-beam type structure, and silica density is measured with a infrared spectrometry using the Lambert-beer method. However, such a system occurs measuring error of large range and inconsistency of a light source, because of measuring a standard sample and a measuring sample alternatively. This paper introduces a method that the sensor module has a split-beam type structure and a tungsten lamp. The proposed system can measure silica density quickly and precisely more than those composing of a single-beam type structure, because of measuring and comparing with two samples at a same time. And examination results are shown to compare efficiencies of the system and existing commercial products, and for an ammonia influence.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.407-410
• /
• 1995

Many researches on measurement technology has been made and developed by various methods. Considering the measurement environment with cutting fluid, coolant and the like, contact type measurement methods are mostly used. But contact measurement method has measuring force and so the sensing head becomes worn. By these reasons, we considered sensors not influenced by the former fluid and so can acquire accrate measured values using error compensation due to temperature and vibration. For this purpose, eddy current sensors and Extended kalman Filter Algorithm for processing measured data has been used. In this paper, we present new technology that can be used for measuring workpiece with previous bad environment using direct method and comparison measurement method. We used cylindrical workpieces which were produced by grinding machine for the target.

• Journal of Sensor Science and Technology
• /
• v.19 no.1
• /
• pp.36-42
• /
• 2010

This paper describes a multi channel measurement system which can measure the cellular respiration level in a solution containing cells by using a Clark-type sensor with the solution temperature control unit. The Clark-type sensor can measure the cellular respiration level in the solution because it can measure the reduction current depending on the dissolved oxygen level in the solution. This measurement system was maintained the temperature within ${\pm}0.1^{\circ}C$ of the setting temperature value by on/off control method in order to measure the precise cellular respiration level. The measurement system showed that the applied voltage to the working electrode was very stable(-0.8 V$\pm$ 0.0071 V) by using proportional control method. From the current measurement, the response time and the linearity correlation coefficient were 25 sec and 0.94, respectively, which are very close to the results of the commercial product. Using this system and the fabricated Clarktype sensor, the average ratio of the uncoupled OCR(oxygen consumption rate) to the coupled OCR was 1.35 and this is almost the same as that obtained from a commercial systems.

• Journal of Sensor Science and Technology
• /
• v.13 no.4
• /
• pp.287-291
• /
• 2004

A capacitive type humidity sensor has been fabricated using a polyimide film without hydrophobic elements and its characteristics has been evaluated for hermeticity measurement of micro packages. For a highly sensitive humidity sensor, a polyimide film without hydrophobic elements has been synthesized and used instead of using a commercial one in which 7 group elements such as fluorine or chlorine are included. Sensitivity, stability and hysteresis has been performed to characterize the fabricated sensors. The sensitivity defined as normalized percent capacitance change was 0.3751%RH and hysteresis was 0.77% in the range of 10%RH to 90%RH. Maximum deviation from the average capacitance measured for 120 minutes at 50%RH was 0.25%. The proposed humidity sensor can be used for hermeticity measurement of micro packages.

• International Journal of Aeronautical and Space Sciences
• /
• v.6 no.1
• /
• pp.17-26
• /
• 2005

An optical phase tracking technique for an extrinsic Fabry-Perot interferometer (EFPI) is proposed in order to overcome interferometric non-linearity. Basic idea is utilizing strain-rate information, which cannot be easily obtained from an EFPI sensor itself. The proposed phase tracking system consists of a patch-type EFPI sensor and a simple on-line phase tracking logic. The patch-type EFPI sensor comprises an EFPI and a piezoelectric patch. An EFPI sensor itself has non-linear behavior due to the interferometric characteristics, and a piezoelectric material has hysteresis. However, the composed patch-type EFPI sensor system overcomes the problems that can arise when they are used individually. The dynamic characteristics of the proposed phase tracking system were investigated, and then the patch-type EFPI sensor system was applied to the active suppression of flutter, dynamic aeroelastic instability, of a swept-back composite plate structure. The proposed system has effectively reduced the amplitude of the flutter mode, and increased flutter speed.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.5
• /
• pp.209-213
• /
• 2021

For the human body shape information, body measurement techniques using a tape measure or image analysis are used. However, there is a demand for a method with high measurement accuracy and reproducibility while being simple. In this paper, domestic and foreign patent research related to body size measurement technology was conducted to identify the development trend of the related technology. WISDOMAIN DB was used to search for patents published in Korea, the United States, Japan, and Europe, and valid patents were derived by defining the technical scope of major and medium classifications and sub-categories. For the derived patents, patent trends by year, major applicants by country, and the status of technological fields were analyzed. In the field of body size measurement technology, the proportion of patent applications filed in Korea is high, indicating that Korea is leading the patent application in this field. Although the number of patent applications in the field of sensor-type measurement technology was not large, it has an advantage in measurement simplicity, so the development of related technology is expected to contribute to the improvement of measurement accuracy related to body composition analysis.

• Journal of Sensor Science and Technology
• /
• v.30 no.5
• /
• pp.342-348
• /
• 2021

For the characterization or failure analysis of electronic devices such as PCB (printed circuit boards), the most common method is the measurement of voltage waveforms with an oscilloscope. However, because there are many types of problems that cannot be detected by voltage waveform analysis, several other methods such as X-ray transmission, infrared imaging, or eddy current measurement have been applied for these analyses. However, these methods have also been limited to general analyses because they are partially useful in detecting physical defects, such as disconnections or short circuits. Fundamentally current waveform measurements during the operation of electronic devices need to be performed, however, commercially available current sensors have not yet been developed, particularly for applications in highly integrated PCB products with sub-millimeter fine pitch. In this study, we developed a highly sensitive PHR (planar hall resistance) magnetic sensor for application in highly integrated PCBs. The developed magnetic sensor exhibited sufficient features of an ultra-small size of less than 340 ㎛, magnetic field resolution of 10 nT, and current resolution of 1 mA, which can be applicable for PCB analyses. In this work, we introduce the development process of the magnetic sensing probe and its characteristic results in detail, and aim to extend this pin-type current probe to applications such as current distribution imaging of PCBs.