• Steel and Composite Structures
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• v.41 no.6
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• pp.805-820
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• 2021

In this research, the buckling and free vibration of three-phase carbon nanotubes/ fiber/ polymer piezoelectric nanocomposite face sheet sandwich microbeam with microsensor and micro-actuator surrounded in elastic foundation based on modified couple stress theory (MCST) is investigated. Three types of porous materials are considered for sandwich core. Higher order (Reddy) and sinusoidal shear deformation beam theories are employed for the displacement fields. Sinusoidal surface stress effects are extracted for sinusoidal shear deformation beam theory. The equations of motion are derived by Hamilton's principle and then the natural frequency and critical buckling load are obtained by Navier's type solution. The determined results are in good agreement with other literatures. The detailed numerical investigation for various parameters is performed for this microsensor-microactuator. The results reveal that the microsensor-microactuator enhanced by increasing of Skempton coefficient, carbon nanotubes diameter length to thickness ratio, small scale factor, elastic foundation, surface stress constants and reduction in porous coefficient, micro-actuator voltage and CNT weight fraction. The valuable results can be expedient for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.237-244
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• 1997

A new planar-type microsensor, which had a platinum heater and a sensing layer on the same plane was fabricated on silicon substrate with stress-relieved PSG(phosphosilicate glass)/$Si_{3}N_{4}$(800nm/150nm) diaphragm. The proposed planar-type microsensor could be fabricated by simple silicon process using only 3 masks for photolithography process compared with 5 or 6 masks of the typical micro-gas sensor. The thermal properties of the microsensor from thermal simulation were compared with those of the fabricated microheater. Although there are some discrepancy between the simulation result and the result from the fabricated microheater, the thermal simulation by FEM was proved to be an useful method to evaluate the thermal properties of microheater. The sensing characteristics of the fabricated microsensor with the planar-type heater were investigated also.

• Proceedings of the IEEK Conference
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• summer
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• pp.330-333
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• 2004

Microsensor nodes is energy limited in sensor networks. If nodes had been stop in working, sensor network can't acquire sensing data in that area as well as routing path though the sensor can't be available. So, it's important to maximize the life of network in sensor network. In this paper, we look at communication protocol, which is modified by LEACH(Low-Energy Adaptive Clustering Hierarchy). We extend LEACH's stochastic cluster-head selection algorithm by a Position-based Selection (PB-Leach). This method is that the sink divides the topology into several areas and cluster head is only one in an area. PB-Leach can prevent that the variance of the number of Cluster-Head is large and Cluster-Heads are concentrated in specific area. Simulation results show that PB-Leach performs better than leach by about 100 to $250\%.$

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1430-1435
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• 2007

We developed a 440MHz surface acoustic wave (SAW) microsensor integrated with pressure-temperature sensors and ID tag. Two piezoelectric substrates were bonded, in which ${\sim}150\;{\mu}m$ cavity was structured. Four sides were completely sealed by JSR photoresist (PR). Pressure sensor was placed on the top substrate, whereas ill tag and temperature sensor were placed on the bottom substrate. Using network analyzer, the developed microsensor was wirelessly tested. Sharp reflection peaks with high S/N ratio, small signal attenuation, and small spurious peaks were observed. All the reflection peaks were well matched with the coupling of mode (COM) simulation results. With a 10mW RF power from the network analyzer, a ${\sim}1$ meter readout distance was observed. Eight sharp ON reflection peaks were observed for ID tag. Temperature sensor was characterized from $20^{\circ}C$ to $200^{\circ}C$. A large phase shift per unit temperature change was observed. The evaluated sensitivity was ${\sim}10^{\circ}/^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 1993.07a
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• pp.8.1-8
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• 1993

• Transactions on Electrical and Electronic Materials
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• v.6 no.4
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• pp.173-176
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• 2005

A new $MoO_3$ based microsensor with low power consumption was presented. Typical size of sensor was 5mm in width and 8mm in length. As a sensitive electrode, $MoO_3$ was successfully fabricated by IC technology on pyrex glass of $250{\mu}m$ in thickness. After annealing at $550^{\circ}C$ for 3hrs, the film was fully crystallized and demonstrated as pure $MoO_3$ structure. The grain size of $MoO_3$ was plat like and typical size was about $1{\mu}m$. Based on the results of sensitivity measurement, $MoO_3$ microsensor shows especially high selectivity to $H_2$ reducing gas atmosphere. The applied heater power was lower than 0.5 Watt.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1266-1272
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• 2003

This paper presents a new class of magnetic microsensors based on the Hall effect in AC microplasma. In the theoretical study, we develop a simple model of the plasma Hall sensor and express the plasma Hall voltage as a function of magnetic field, plasma discharge field, pressure, and electrode geometry. On this basis, we have designed and fabricated magnetic microsensors using AC neon plasma. In the experiment, we have measured the Hall voltage output of the plasma microsensors for varying five different conditions, including the frequency and the magnitude of magnetic field, the frequency and the magnitude of plasma discharge voltage, and the neon pressure. The fabricated magnetic microsensors show a magnetic field sensitivity of 8.87${\pm}$0.18㎷/G with 4.48% nonlinearity.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.310.1-310.1
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• 2007

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.457-457
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• 2004

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.371-377
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• 2008

Our precedent study has reported glass-PDMS (polydimethylsiloxane) based biochip for the gene PCR (polymerase chain reaction). To prevent the contamination of bio sample, the once used biochip must not be used repeatedly. However, the fabrication cost of microheater and microsensor of the biochip was not cheap to use it as a disposable chip. This paper proposes new PCR-chip where the glass substrate integrated with the microheater and microsensor is detachable from the reaction chamber where the sample is injected. That makes it possible to reuse the glass substrate repeatedly. The performance of the proposed detachable PCR-chip was compared with that of the precedent monolithic PCR-chip. The results showed that the SRY (sex determining Y chromosome) gene PCR was successfully performed in the detachable chip compared with the monolithic chip. However, the more efforts to improve the efficiency of surface treatment of PDMS chip are needed to increase the possibility of applying the detachable chip to the detecting of male infertility.