• 한국군사과학기술학회지
• /
• 제23권3호
• /
• pp.294-301
• /
• 2020

Man-In-Simulant Test(MIST) provides a test method to evaluate chemical protective equipments such as protective garments, gloves, footwear and gas mask. The MIST chamber is built to control concentration of chemical vapor that has a activity space for two persons. Non-toxic methyl-salicylate(MeS) is used to simulate chemical agent vapor. We carried out to measure inward leakage MeS vapors by using passive adsorbent dosimeter(PAD) which are placed on the skin at specific locations of the body while man is activity according to the standard procedure in MIST chamber. But more time is required for PADs and there is concern of contamination in PADs by recovering after experiment. Therefore detector for measuring in real time is necessary. In order to analyze in real time the contamination of the personal protective equipment inside the chemical environment, we have developed a wireless real-time gas detector. The detector consists of 8 gas-sensors and 1 control-board. The control-board includes a CPU for processing a signal, a power supply unit for biasing the sensor and Bluetooth-chipset for transmission of signals to external PC. All signals from gas-sensors are converted into digital signals simultaneously in the control-board. These digital signals are stored in external PC via Bluetooth wireless communication. The experiment is performed by using protective equipment worn on manikin. The detector is mounted inside protective equipment which is capable of providing a real-time monitoring inward leakage MeS vapor. Developed detector is demonstrated the feasibility as real-time detector for MIST.

• 한국염색가공학회지
• /
• 제33권2호
• /
• pp.49-63
• /
• 2021

In this study, a convenient approach for sensitive, quick and simple detection of hazardous acids was investigated. A series of azo dyes were synthesized and applied as a chemosensor for the acid detection both on fibers and in solution. Various aniline, benzothiazole or isoxazole derivatives were used as diazo component and coupled with N-benzyl-N-ethylaniline or 2,2'-(phenylimino)bis-ethanol to give azo based dyes. The acid sensing phenomenon was observed by naked-eye and detection was further confirmed by UV-Vis spectrophotometer and hue difference(ΔH^*) evaluation. The developed sensors showed a distinct and quick color change from yellow to magenta by addition of trace amounts of the hazardous acids. The absorption maxima was shifted to a longer wavelength by 70 ~ 150nm and hue difference(ΔH^*) was 60 ~ 120°. A cotton fiber coated with Dye 1 exhibited excellent storage stability under various temperature(-30 ~ 43℃) and humidity(30 ~ 80%) conditions without discoloration and fading of the fiber sensors. Also the acid sensing properties were maintained.

• Journal of Biosystems Engineering
• /
• 제33권6호
• /
• pp.410-415
• /
• 2008

On-line monitoring of fresh tomato paste processing was done using two radio frequency (RF) sensors resonant at 85 and 110 MHz. Fresh tomato juice with soluble solid content of about $5^{\circ}Brix$ was evaporated up to $23^{\circ}Brix$ and diluted down to about $5^{\circ}Brix$ again with a pilot scale evaporator. The RF sensors were installed in a processing pipe and monitored. The pastes at a specific $^{\circ}Brix$ level were sampled and analyzed for physical properties such as soluble solid content and viscosity. The relationships between sensor outputs and measured physical properties were analyzed. Analysis results showed RF sensor is feasible to apply on-line monitoring of tomato paste processing.

• Transactions on Electrical and Electronic Materials
• /
• 제7권2호
• /
• pp.58-61
• /
• 2006

Carefully designed ZnO nanowire-film hybrid nanostructure, composed of a bottom ZnO film, ZnO nanowire arrays, and a top ZnO film, was consecutively fabricated by adjusting the supersaturation conditions using a metal-organic chemical vapor deposition (MOCVD) to utilize the vertically aligned ZnO nanowires as the oxygen sensors. The decrease of current flow through ZnO nanowire arrays increasing oxygen pressure showed the high potential for the application of the ZnO hybrid nanostructure to the oxygen sensors. In addition, it was confirmed that the oxygen sensing characteristics of this hybrid nanostructure were attributed to the defects near the surface of the nanowires.

• 센서학회지
• /
• 제21권3호
• /
• pp.180-185
• /
• 2012

${\gamma}$-ray radiolysis was used to functionalize networked ZnO nanowires with Au nanoparticles. The networked ZnO nanowires were prepared through a vapor phase selective growth method. The sensing performances of the Au-functionalized ZnO nanowires were investigated in terms of $NO_2$, CO and benzene gases. The Au-funtionalized ZnO nanowire sensors showed an applicable, reliable capability to detect the gases, indicating their potential in chemical gas sensors.

• 센서학회지
• /
• 제28권1호
• /
• pp.7-12
• /
• 2019

Significant progress has been made recently in detection of highly sensitive volatile organic compounds (VOCs) using chemical sensors. Combined with the progress in design of micro sensors array and electronic nose systems, these advances enable new applications for detection of extremely low concentrations of breath-related VOCs. State of the art detection technology in turn enables commercial sensor systems for health care applications, with high detection sensitivity and small size, weight and power consumption characteristics. We have been developing an intelligent electronic nose system for detection of VOCs for healthcare breath analysis applications. This paper reviews our contribution to monitoring of respiratory diseases and to diabetic monitoring using an intelligent electronic nose system for detection of low concentration VOCs using breath analysis techniques.

• 센서학회지
• /
• 제30권4호
• /
• pp.218-222
• /
• 2021

Wearable multi-sensors based on nanocrystals have attracted significant attention, and studies on patterning technology to implement such multi-sensors are underway. Conventional patterning processes may affect material properties based on high temperatures and harsh chemical conditions. In this study, we developed an inkjet printing technique that can overcome these drawbacks through the application of patterning processes at room temperature and atmospheric pressure. Nanocrystal-based ink is used to adjust properties efficiently. Additionally, the viscosity and surface tension of the solvents are investigated and optimized to increase patterning performance. In the patterning process, the electrical, electrothermal, and electromechanical properties of the nanocrystal pattern are controlled by the ligand exchange process. Experimental results demonstrate that a multi-sensor with a temperature coefficient of resistance of 3.82 × 10^-3 K^-1 and gauge factor of 30.6 can be successfully fabricated using one-step inkjet printing.

• 센서학회지
• /
• 제13권1호
• /
• pp.72-77
• /
• 2004

In this paper, we fabricated an apparatus of the electro-chemical discharge drilling for boring narrow through-hole into a glass. In the electrolyte, electro-chemical discharge creates high temperature condition by the electro-discharge energy. Therefore, glass are removed by the accelerated chemical reaction with glasses and chemicals in the high temperature condition. For optimization of the electro-chemical discharge drilling, the process condition was studied experimentally as a function of the electrolyte concentration, supply voltage and process time. The optimum condition was from DC25V to DC30V of applied voltage, 35 wt% NaOH solution.

• 센서학회지
• /
• 제14권1호
• /
• pp.56-61
• /
• 2005

This paper present characteristics of chromium oxide thin-film as piezoresistive sensors, which were deposited on Si substrates by DC reactive magnetron sputtering in an argon-Oxide atmosphere for high temperature applications. The chemical composition, physical and electrical properties and thermal stability ranges of the $CrO_{x}$ sensing elements have studied. $CrO_{x}$ thin films with a linear gauge factor(GF${\fallingdotseq}$15), high electrical resistivity (${\rho}$ = $340{\mu}{\Omega}cm$) and TCR<-55 ppm/$^{\circ}C$ have been obtained. These $CrO_{x}$ thin films may allow high temperature pressure sensor miniaturization to be achieved.

• 반도체디스플레이기술학회지
• /
• 제11권1호
• /
• pp.55-59
• /
• 2012

NOx is one of the toxin gases, which is mainly causing the optic-chemical smog phenomena, and decreasing in the function of nose and taste. Especially, NO is easily reacting with $O_3$, and then becoming the $NO_2$. $NO_2$ is mainly causing the acidulation rain. So, we should develop the NOx gas sensing system to detect NOx gas. In this paper, we present the microstructure and the NOx gas detecting properties of the nitrocellulose/MWCNT thin film coated by the air-spray on the glass substrate. The nitrocellulose/MWCNT-based gas sensors have been studied detecting NOx molecules of a ppm-level at the temperature range of $30{\sim}120^{\circ}C$. The resistance of the sensors decreases when the sensors are exposed to NOx gas. As a results, we obtained the nitrocellulose/MWCNT sensors with the sensitivity of 0.6%/sec under the 0.8 ppm of NOx gas concetration. Also, we get the activation energy of 0.202eV from the sensor for the 0.3 ppm of NOx gas concentration.