• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1087-1090
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• 2003

In this study, experimental procedures were suggested to investigate the sloshing behavior of a liquid storage tank subjected to inevitably external vibrating conditions. For this purpose. liquid storage tank with rectangular cross section was made of an acrylic resin for the visualization of liquid fluctuation. A specially designed vibrator was used to provide a specified vibrating condition to the liquid storage tank. Extrapolation technique was applied to determine sloshing natural frequency by using various sloshing frequencies at each vibrating displacement and liquid contents at a fixed vibrating frequency. Sloshing mode was also determined from continuous images or liquid fluctuation captured from a video camera. In addition, change in the height of the liquid free surface was measured by using a floating target and a laser displacement sensor. It is found that the suggested method can be applicable to identify the sloshing behavior of liquid storage tank with rectangular cross section.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2867-2872
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• 2012

SAN/$BMIPF_6$ nanofibers were fabricated by an electrospinning process and used as chemiresistors for sensing alcohol vapours. A hydrophobic and air-stable ionic liquid, $BMIPF_6$, was used to impart electrical conductivity to insulating SAN nanofibers. The effects of $BMIPF_6$ addition on the morphology of the nanofibers were explained in terms of surface tension, viscosity and conductivity. After exposing the SAN/$BMIPF_6$ nanofibers collected on an interdigitated electrode to alcohol vapours (ethanol, 1-propanol and 1-butanol), the resistance of the nanofibers decreased due to adsorption of alcohol molecules. The electrospun SAN/$BMIPF_6$ nanofibers sensor exhibited good sensitivity and reproducibility.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.156-164
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• 2016

We demonstrated the pretilt angle effect on the viewing angle properties of a single-domain fringe-field switching (FFS) liquid crystal (LC) mode. By performing the Póincare sphere analysis, we investigated, in detail, the origin of the viewing angle asymmetry that exists in the single-domain FFS LC mode both in the field-on and field-off states. Using this analysis, we confirmed that the pretilt angle reduces the viewing angle symmetry in the single-domain FFS LC mode. Finally, we examined the effect of a zero pretilt angle on the viewing angle symmetry by evaluating real single-domain FFS LC cells.

• Journal of Sensor Science and Technology
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• v.4 no.3
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• pp.9-14
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• 1995

For the development of liquid density measuring sensor using the natural frequency of a pipe, its principle and construction method were described. The stainless steel pipe, which has length of 32 cm, inside diameter of 2.3 cm and outside diameter of 2.5 cm, was used for the sensor. The exciting coil and the photo sensor were used to excite and to pick-up it, and the feedback circuit was designed to continue its vibrating. The natural frequency was consistent with the result of the spectrum analysis. It had a linearity of 0.0027 % and a sensitivity of 0.032 % in liquid density range from $0.8\;g/cm^{3}$ to $1.4\;g/cm^{3}$ and its frequency variation ratio was 0.024 $%/^{\circ}C$ in temperature range from $10^{\circ}C$ to $35^{\circ}C$.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.337-338
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• 2014

In this study, a method of using a capacitance sensor was investigated as a means to measure the mass fraction of a type of harmful substance. Using MEMS process, we developed a capacitance sensor and studied the real time mass fraction with harmful substance mixture liquid.

• Journal of Sensor Science and Technology
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• v.33 no.2
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• pp.63-69
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• 2024

A novel method for measuring hydrogen concentration is introduced, along with its working principle and a novel detection algorithm. This configuration requires no additional reference compartment for potentiometric electrochemical measurements; therefore, it is the most suitable for measuring dissolved hydrogen in the liquid phase. The sensor's electromotive force saturates at a certain point, depending on the hydrogen concentration during the heating process of the sensor operation. This dynamic temperature scanning method provides higher sensitivity than the constant temperature measurement method.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.287-290
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• 2015

Liquid crystal polymer (LCP) is a thermoplastic polymer with superior mechanical and thermal properties. In addition, its characteristics include very low water absorption rate and possibility to apply bonding process under low temperature. In this study, LCP is utilized as a packaging material for a microelectronic system (MEMS) based safety device with suggestion of a low temperature packaging process. Highly sensitive and stable capacitive type humidity sensor is fabricated to investigate hermeticity of the packaged MEMS device.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.2 s.140
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• pp.73-79
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• 2005

The characteristics of a tilt sensor utilizing the resistance change of an electrolyte associated with inclination is investigated, and a dynamic compensation modeling is proposed to make the real-time measurement of the absolute slope possible even with sporadically dynamic motion. Although the proposed system is small, economical and accurate for quasi-steady slope measurement, since it contains a freesurface the evolution of the liquid surface that has no direct relation to the real slope must be excluded for any rapid rotations or translations. For various artificial motions the response of the sensor is analyzed and simplified modeling equations are proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.747-752
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• 2008

Fiber-guided sensor system using a generator and a receiver can detect the amplitude of load or pressure. However, this type of sensor can show some difficulties in detecting the location of damages and pressure loadings. To overcome this weakness of this type, the ultrasonic active fiber sensor, which has an integrated ultrasonic generator and sensing part, was developed in this study. By using this sensor system, the location of mechanical loads can be exactly detected. Moreover, the ultrasonic active fiber sensor is more cost-effective than an ultrasonic fiber sensor using two piezoelectric transducers which are used as a generator and a receiver, respectively. Two applications of the ultrasonic active fiber sensor are demonstrated: cure monitoring of lead and measurement of liquid level. Present results showed that the active fiber sensor can be applied for various environmental sensing.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.214-214
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• 2000

This paper deals with the non contact optical sensor to measure the shape of transparent plates such as glass panel of LCD(Liquid Crystal Display). The conventional methods to obtain the shape or thickness of a transparent plates are contact type sensor such as LVOT(Linear Variable Differential Transformer). Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition, the high temperature glass casting makes the size of sensor body changed. These reasons makes the sensor degraded. In this paper, to overcome these problem, we proposed a low cost noncontact optical sensor this is composed of the Hologram laser unit of a CD-Pickup and a plastic lens. To evaluate the performance of the proposed optical sensor, a series of experiments were performed for various measurement condition. Based upon observation of the experimental result, the developed sensor shows good result for measuring the shape of transparent plates.