• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.7
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• pp.82-88
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• 1993

This paper describes fabrication of relative type capacitive pressure sensor to be in great demand for many fields. The fabricated sensor consists of two parts` a sensing diaphragm and a pyrox glass cover. The sensor size is 4.5${\times}3.4mm$^{2})$ and 400$\mu$m thick. To improve the nonlinearity, this sensor is designed a rectangular silicon diaphragm with a center boss structure, and in order to improve the temperature characteristics of the sensor in a packaging process, the sensing element is mounted on the pyrex glass support. Some suggestions toward the design and fabrication of improved sensors have been presented. The zero pressure capacitance, Co of sensor is 26.57pF, and the change of capacitance, ${\Delta}$C is 1.55pF from 0Kgf/Cm$^{2}$ to 1Kgf/Cm$^{2}$ at room temperature. The nonlinearity of the sensor output with center boss diaphragm is 1.29%F.S., and thermal zero shift and thermal sensitivity shift is less than 1.43%F.S./$^{\circ}C$and 0.14% F.S./$^{\circ}C$, respectively.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.246-247
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• 2005

This study suggested fanless thermal design using CAE technique for the information storage system under the serious thermal problem. At first, main heat flow was controlled by CAE based fanless heat sink design not to influence sensitive optical pick-up sensor. Then, vent parametric studies found a thermal solution about highly concentrated case top heat due to fanless. These CAE results were verified by experimental methods. As a consequence of newly designed thermal path, thermal specification of optical pick-up sensor was satisfied and fanless thermal design for the information storage system was achieved.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.36-42
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• 2001

This paper deals with finite element analyses of residual stresses causing popping up which are induced in micromachining processes of a microaccelerometer sensors. The paddle of the micro accelerometer sensor is designed symmetric with respect to the direction of the beam. After heating the tunnel gap up to 100 degree and get it through the cooling process and the additional beam up to 80 degree and get it through the cooling process. We learn the thermal internal stresses of each shape and compare the results with each other, after heating the tunnel gap up to 400 degree during the Pt deposition process. Finally we find the optimal shape which is able to minimize the internal stresses of microaccelerometer sensor. We want to seek after the real cause of this pop up phenomenon and diminish this by change manufacturing processes of microaccelerometer sensor by electrostatic force.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.49-55
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• 2016

Nowadays there are magnetic sensors in a wide variety of equipment such as computers, cars, airplanes, medical and industrial instruments. In many of these applications the magnetic sensors offer safe and non-invasive means of detection and are more reliable than other technologies. The electric current in a conductor generates a magnetic field detected by this type of sensor. This work aims to define a package dedicated to an electrical current sensor using a MTJ (Magnetic Tunnel Junction) as a sensing device. Four different proposals of packaging, three variations of the chip on board (CoB) package type and one variation of the thin small outline package (TSOP) were analyzed by COMSOL modeling software by simulating a brad range of current injection. The results obtained from the thermal and magnetic analysis has proven to be very important for package improvements, specially for heat dissipation performance.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1842-1846
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• 2008

This work reports development of novel liquid-level sensors based on the $3{\omega}$ method. The sensors determine the liquid level by measuring the thermal response as in the conventional hot-wire technique. However the sensors employ an AC heating method to enhance the sensitivity, noise resistance and time response. Also, the microfabricated thin-film structure of the sensor provides mass-producibility as well as improved sensor performance owing to the increase in the surface-volume ratio of the sensor. Two different types of the sensor are developed: one for point detection of the fluid phase and the other for monitoring continuous variation of liquid level. Notable is that the performance of the sensor is not considerably affected by the liquid flow.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.199-202
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean observation and meteorological observation. Conventional thermal control design, using MLI (Multi Layer Insulation), OSR (Optical Solar Reflector), heater and heat pipe, is utilized. Ka-band components are installed on South wall, while other equipment for sensors are installed on the opposite side, North wall. High dissipating communication units are located on external (surface) heat pipe and are covered by internal insulation blankets to decouple them from the rest of the satellite. External satellite walls are covered by MLI or OSR for insulation from space and for rejection internal heat to space. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. Single solar array wing is adopted in order to secure clear field of view of radiant cooler of IR meteorological sensor. This paper presents principles of thermal control design for the COMS.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.82-84
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• 2005

In a transformer, thermal stress is the most influential parameter affecting the aging behavior of insulation system. The aging behavior of insulation system in transformer is determined mainly by the thermal conditions inside the transformer. The thermal stress on the insulation system may occur from operation in a high temperature caused by overloading or local overheating. Thus, this paper investigated the condition monitoring of insulation condition in thermally accelerated aged transformer oils by in-situ sensor. The condition of aged samples was investigated by measurements of relative permittivity i.e. capacitance change by capacitive sensor. Results from the experiments are presented in this paper.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.754-761
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• 2013

Thermal displacement is an important issue in machine tool systems. During the last several decades, thermal error compensation technology has significantly reduced thermal distortion error; this success has been attributed to the development of a precise, robust thermal error model. A major advantage of using the thermal error model is instant compensation for the control variables during the modeling process. However, successful application of thermal error modeling requires correct determination of the temperature sensor placement. In this paper, a procedure for predicting thermal-mode-based thermal error is introduced. Based on this thermal analysis, temperature sensors were positioned for multiple heat-source models. The performance of the sensors based on thermal-mode error analysis, was compared with conventional methods through simulation and experiments, for the case of a slide table in a transient state. Our results show that for predicting thermal error the proposed thermal model is more accurate than the conventional model.

• Smart Structures and Systems
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• v.19 no.3
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• pp.299-307
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• 2017

The magneto-electro-elastic (MEE) material under thermal environment exhibits pyroelectric and pyromagnetic coefficients resulting in pyroelectric and pyromagnetic effects. The pyroelectric and pyromagnetic effects on the behavior of multiphase MEE sensors bonded on top surface of a mild steel beam under thermal environment is presented in this paper. The aim of the study is to find out how samples having different volume fractions of the multiphase MEE composite behave in sensor applications. This is studied at optimal location on the beam, where the maximum electric and magnetic potentials are induced due to pyroelectric and pyromagnetic effects under clamped-free and clamped-clamped boundary conditions. The sensor which is bonded on the top surface of the beam is modeled using 8-node brick element. The MEE sensor bonded on mild steel beam is subjected to uniform temperature rise of 50K. It is assumed that beam and sensor is perfectly bonded to each other. The maximum pyroelectric and pyromagnetic effects on electric and magnetic potentials are observed when volume fraction is ${\nu}_f=0.2$. The boundary conditions significantly influence the pyroelectric and pyromagnetic effects on electric and magnetic potentials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.113-114
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• 2010