• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.737-740
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• 2001

This paper describes the fabrication and characteristics of CrN thin-film type pessure sensors, which the sensing elements were deposited on SUS. 630 diaphragm by DC reactive magnetron sputtering in an argon-nitride atmosphere(Ar-(10%)N$_2$). The optimized condition of CrN thin-film sensing elements was thickness range of 3500${\AA}$ and annealing condition(300$^{\circ}C$, 3 hr) in Ar-10 %N$_2$deposition atmosphere. Under optimum conditions, the CrN thin-films for strain gauges is obtained a high resistivity, $\rho$=1147.65 ${\mu}$$\Omega$cm, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal, 11.17. The output sensitivity of fabricated CrN thin-film type pressure sensors is 2.36 mV/V, 4∼20 mA and the maximum non-linearity is 0.4 %FS and hysteresis is less than 0.2 %FS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1375-1377
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• 2001

This paper describes the fabrication and characteristics of CrN thin-film type pessure sensors, in which the sensing elements were deposited on SUS. 630 diaphragm by DC reactive magnetron sputtering in an argon-nitride atmosphere(Ar-(10%) $N_2$). The optimized condition of CrN thin-film sensing elements was thickness range of 3500$\AA$ and annealing condition($300^{\circ}C$, 3 hr) in Ar-10 %$N_2$ deposition atmosphere. Under optimum conditions, the CrN thin-films for strain gauges is obtained a high resistivity, $\rho$=1147.65 ${\mu}{\Omega}$cm, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal, 11.17. The output sensitivity of fabricated CrN thin-film type pressure sensors is 2.36 mV/V, 4$\sim$20 mA and the maximum non-linearity is 0.4 %FS and hysteresis is less than 0.2 %FS..

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.277.2-277.2
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• 2014

For next-generation electronic applications, human-machine interface devices have recently been demonstrated such as the wearable computer as well as the electronic skin (e-skin). For integration of those systems, it is essential to develop many kinds of components including displays, energy generators and sensors. In particular, flexible sensing devices to detect some stimuli like strain, pressure, light, temperature, gase and humidity have been investigated for last few decades. Among many condidates, a pressure sensing device based on organic field-effect transistors (OFETs) is one of interesting structure in flexible touch displays, bio-monitoring and e-skin because of their flexibility. In this study, we have investigated a flexible e-skin based on highly sensitive, pressure-responsive OFETs using microstructured ferroelectric gate dielectrics, which simulates both rapidly adapting (RA) and slowly adatping (SA) mechanoreceptors in human skin. In SA-type static pressure, furthermore, we also demonstrate that the FET array can detect thermal stimuli for thermoreception through decoupling of the input signals from simultaneously applied pressure. The microstructured highly crystalline poly(vinylidene fluoride-trifluoroethylene) possessing piezoelectric-pyroelectric properties in OFETs allowed monitoring RA- and SA-mode responses in dyanamic and static pressurizing conditions, which enables to apply the e-skin to bio-monitoring of human and robotics.

• 농업과학연구
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• 제40권1호
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• pp.53-59
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• 2013

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

• 한국구조물진단유지관리공학회 논문집
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• 제5권4호
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• pp.215-225
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• 2001

Stress waves monitored on the surface of structures under various loading conditions can provide useful information on the structural health status. In this paper, stress waves are measured by several sensors when a steel beam is impacted by a ball drop. The sensors used include the piezo-electric film Sensor, the electrical strain gage, and the ultrasonic transducer, and special attention is given to the pieza film sensor. The wavelet transform is used for the time-frequency analysis of dispersive waves propagating in the beam. The velocities of the wave produced in the team due to the lateral impact is found to be frequency-dependent and identified as the flexural wave velocity based on the comparisons with the Timoshenko beam theory. A linear impact site identification method is developed using the flexural wave, and the impact sites of the beam can be accurately estimated by the piezo film sensors. It is found that the piezo film sensor is appropriate for sensing stress waves due to impact and for locating impact sites in the beam.

• 센서학회지
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• 제32권5호
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• pp.295-299
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• 2023

Herein, we propose a simple fabrication method for MXene-coated V-groove sensors for applications. To enhance the sensitivity of this sensor, we applied MXene particles, instead of conventional metal layers, as a sensing material on the sensor's surface. This allows for an easier fabrication, as well as higher sensitivity of the sensor compared to those of our previously demonstrated metal-based V-groove sensor. Additionally, polyurethane-acrylate, a UV-curable liquid polymer, can be easily applied using micro-electromechanical systems-based surface-texture micromachining. The sensor sensitivity is approximately 0.08 /mm, and it can be improved by increasing the number of V-grooves. We believe that the proposed MXene-based wearable sensor offers a great potential in detecting various types of motions characteristic of human activities.

• 센서학회지
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• 제33권3호
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• pp.173-178
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• 2024

Development of pressure sensors for harsh environments with high pressure, humidity, and temperature is essential for many applications in the aerospace, marine, and automobile industries. However, existing materials such as polymers, adhesives, and semiconductors are not suitable for these conditions and require materials that are less sensitive to the external environment. This study proposed a pressure sensor that could withstand harsh environments and had high durability and precision. The sensor comprised a piezoresistor pattern and an insulating film directly formed on a stainless-steel membrane. To achieve the highest sensitivity, a pattern design method was proposed that considered the stress distribution in a circular membrane using finite element analysis. The manufacturing process involved depositing and etching a dielectric insulating film and metal piezoresistive material, resulting in a device with high linearity and slight hysteresis in the range of a maximum of 40 atm. The simplicity and effectiveness of this sensor render it a promising candidate for various applications in extreme environments.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.86-95
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• 2006

Brillouin backscatter is a type of reflection that occurs when light is shone into an optical fibre. Brillouin reflections are very sensitive to changes in the fibre arising from external effects, such as temperature, strain and pressure. We report here several case studies on the measurement of strain using Brillouin reflections. A mechanical bending test of an I beam, deployed with both fiber optic sensors and conventional strain gauge rosettes, was performed with the aim of evaluating: (1) the capability and technical limit of the DTSS technology for strain profile sensing; (2) the reliability of strain measurement using fiber optic sensor. The average values of strains obtained from both DTSS and strain gauges (corresponding to the deflection of I beam) showed a linear relationship and an excellent one-to-one match. A practical application of DTSS technology as an early warning system for land sliding or subsidence was examined through a field test at a hillside. Extremely strong, lightweight, rugged, survivable tight-buffered cables, designed for optimal strain transfer to the fibre, were used and clamped on the subsurface at a depth of about 50cm. It was proved that DTSS measurements could detect the exact position and the progress of strain changes induced by land sliding and subsidence. We also carried out the first ever distributed dynamic strain measurement (10Hz) on the Korean Train eXpress(KTX) railway track in Daejeon, Korea. The aim was to analyse the integrity of a section of track that had recently been repaired. The Sensornet DTSS was used to monitor this 85m section of track while a KTX train passed over. In the repaired section the strain increases to levels of 90 microstrain, whereas in the section of regular track the strain is in the region of 30-50 microstrain. The results were excellent since they demonstrate that the DTSS is able to measure small, dynamic changes in strain in rails during normal operating conditions. The current 10km range of the DTSS creates a potential to monitor the integrity of large lengths of track, and especially higher risk sections such as bridges, repaired track and areas at risk of subsidence.

• 비파괴검사학회지
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• 제31권2호
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• pp.111-117
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• 2011

Vibration monitoring is required for reliable thermosonic testing to decide whether sufficient vibration is achieved in each test for the detection of cracks. From a practical point of view, a cheaper and convenient monitoring method is better for the application to real tests. Therefore, the performance of different sensors for vibration monitoring was investigated and compared in this study to find a convenient and acceptable measurement method for thermosonics. Velocity measured by a laser vibrometer and strain provide an equivalent HI when measured at the same position. The microphone can provide a cheaper vibration monitoring device than the laser and the heating index calculated by a microphone signal shows similar characteristics to that calculated from velocity measured by the laser vibrometer. The microphone frequency response shows that it underestimates high frequency components but it is applicable to practical tests because it gives a conservative value of HI.

• 진공이야기
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• 제4권3호
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• pp.6-11
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• 2017

The tactile sensor of the future robot is becoming a necessity as a sensory organ which can communicate with the person most directly. Recently, the Nature-inspired technology has provided a new direction for the development of these tactile sensors. Here, we review three different nature-inspired tactile sensory system; high sensitivity pressure sensor inspired by beetle wings, highly sensitive strain sensor inspired by the spider's sensory organs, Tactile sensor inspired by human fingertip. These nature-inspired tactile sensors are expected to provide a breakthrough that not only can sensitively measure the pressure, but also delicately recognize the softness and texture of the material just like human.