• Journal of the Korean Institute of Gas
• /
• v.3 no.2 s.7
• /
• pp.17-23
• /
• 1999

The wire and/or wireless data communication system for anti-disaster system of natural gas governor station was developed. In oder to prevent accidents of governor station, the operator was replaced by RTU(Remote Terminal Unit) which gather and transmit safety situation of governor station. The database and MMI(Man Machine Interface) were also developed to analyze the situation of governor station. The data communication between server and RTU was designed to switch automatically from wire to wireless communication and vice versa when one of them failed communication. We also have developed the patrol car management system which was applied GPS(Global Position System)/GIS(Geometric Information System), and the earthquake detection/transmission system which was adopted three dimension acceleration sensor. When a earthquake may occur, the earthquake detection/transmission system monitors data such as PGA(Peak Ground Acceleration), Sl(Spectrum Intensity) and orders the emergency shutoff valve close immediately.

• Journal of the Korean Institute of Gas
• /
• v.25 no.3
• /
• pp.27-38
• /
• 2021

We devised the system to automatically shutdown the boiler and to fundamentally block the harmful gases, including carbon monoxide, into the indoor when the exhaust system swerves: (1) The discharge pressure of the exhaust gas decreases when the exhaust pipe is disconnected. The monitoring system of the exhaust pipe is implemented by measuring the output voltage of APS(Air Pressure Sensor) installed to control the amount of combustion air. (2) The operating software was modified so that when the system recognizes the fault condition of a flue pipe, the boiler control unit displays the fault status on the indoor regulator while shutting down the boiler. In accordance with the ventilation facility standards in the "Rules for Building Equipment Standards" by the Ministry of Land, Infrastructure and Transport, experiments were conducted to ventilate indoor air. When carbon monoxide leaked in worst-case scenario, it was possible to prevent poisoning accidents. However, since 2013, the number of indoor air exchange times has been mitigated from 0.7 to 0.5 times per hour. We observed the concentration exceeding TWA 30 ppm occasionally and thus recommend to reinforce this criterion. In conclusion, if the flue pipe fault detection and the indoor air ventilation system are introduced, carbon monoxide poisoning accidents are expected to decrease significantly. Also when the manufacturing and inspection steps, the correct installation and repair are supplemented with the user's attention in missing flue, it will be served to prevent human casualties from carbon monoxide poisoning.

• Journal of Digital Contents Society
• /
• v.18 no.8
• /
• pp.1661-1669
• /
• 2017

In 2017, Korea has reached 1.3 million elderly people living alone. The government is promoting the basic care service for the elderly by using care workers to check the security of the elderly living alone. However, due to lack of service personnel and service usage rate of elderly care workers, it is difficult to manage. To improve these environmental constraints, this study attempted to construct a monitoring system for elderly people living alone by using sensors such as temperature, humidity, motion detection, and gas leak detection. The sensor periodically collects the current status data of the elderly and sends them to the server, creates a real time graph based on the data, and monitors it through the web. In the monitoring process, when the sensor is out of the range of the specified value, it sends a warning text message to the guardian to inform the current situation, and is designed and implemented so as to support the safety life of the elderly living alone.

• Journal of Sensor Science and Technology
• /
• v.25 no.3
• /
• pp.223-228
• /
• 2016

In this work, we prepared porous WO3 nanofibers (NFs) functionalized by bio-inspired catalytic $Cr_2O_3$ and $Co_3O_4$ nanoparticles as highly sensitive and selective $H_2S$ gas sensing layers. Highly porous 3-dimensional (3D) NFs networks decorated by well-dispersed catalyst NPs exhibited superior $H_2S$ gas response ($R_{air}/R_{gas}$ = 46 at 5 ppm) in high humidity environment (95 %RH). In particular, the sensors showed outstanding $H_2S$ selectivity against other interfering analytes (such as acetone, toluene, CO, $H_2$, ethanol). Exhaled breath sensors using $Cr_2O_3$ and $Co_3O_4$ catalysts-loaded $WO_3$ NFs are highly promising for the accurate detection of halitosis.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.11
• /
• pp.4377-4384
• /
• 2014

According to the World Health Organization (WHO), 1.37 million people died of lung cancer all around the world in 2008, occupying the first place in all cancer-related deaths. However, this number might be decreased if patients were detected earlier and treated appropriately. Unfortunately, traditional imaging techniques are not sufficiently satisfactory for early detection of lung cancer because of limitations. As one alternative, breath volatile organic compounds (VOCs) may reflect the biochemical status of the body and provide clues to some diseases including lung cancer at early stage. Early detection of lung cancer based on breath analysis is becoming more and more valued because it is non-invasive, sensitive, inexpensive and simple. In this review article, we analyze the limitations of traditional imaging techniques in the early detection of lung cancer, illustrate possible mechanisms of the production of VOCs in cancerous cells, present evidence that supports the detection of such disease using breath analysis, and summarize the advances in the study of E-noses based on gas sensitive sensors. In conclusion, the analysis of breath VOCs is a better choice for the early detection of lung cancer compared to imaging techniques. We recommend a more comprehensive technique that integrates the analysis of VOCs and non-VOCs in breath. In addition, VOCs in urine may also be a trend in research on the early detection of lung cancer.

• Journal of the Korean Applied Science and Technology
• /
• v.13 no.3
• /
• pp.105-109
• /
• 1996

It is well known that the metallo- phthalocyanine (MPcs) are sensitive to toxic gaseous molecules such as $NO_2$ and also chemically and thermally stable, Therefore, lots of MPcs have been studied for the potential chemical sensor for $NO_2$ gas using quartz crystal microbalance(QCM) or electrical conductivity. In this study, ultra-thin films of octa(2-ethylhexyloxy)copper-phthalocyanine were prepared by Langmuir-Blodgett method and characterized by using UV-VIS absortion spectroscopy and ellipsometry. Transfer condition, and characterization of LB films were investigated and preliminary results of current-voltage(I-V) characteristics of these films exposed to $NO_2$ gas as a function of film thickness and temperature were discussed.

• Korean Journal of Materials Research
• /
• v.19 no.11
• /
• pp.631-636
• /
• 2009

We investigated the NO gas sensing characteristics of ZnO-carbon nanotube (ZnO-CNT) layered composites fabricated by coaxial coating of single-walled CNTs with a thin layer of 1 wt% Al-doped ZnO using rf magnetron sputtering deposition. Morphological studies clearly revealed that the ZnO appeared to form beadshaped crystalline nanoparticles with an average diameter as small as 30 nm, attaching to the surface of the nanotubes. It was found that the NO gas sensing properties of the ZnO-CNT layered composites were dramatically improved over Al-doped ZnO thin films. It is reasoned from these observations that an increase in the surface-to-volume ratio associated with the numerous ZnO “nanobeads” on the surface of the CNTs results in the enhancement of the NO gas sensing properties. The ZnO-CNT layered composite sensors exhibited a maximum sensitivity of 13.7 to 2 ppm NO gas at a temperature of 200${^{\circ}C}$ and a low NO gas detection limit of 0.2 ppm in dry air.

• Journal of Sensor Science and Technology
• /
• v.29 no.5
• /
• pp.360-364
• /
• 2020

In this study, the colorimetric sensor, polyester (PET) fabric dyed with lead (II) acetate (Pb(C₂H₃O₂)₂), was fabricated and characterized for the detection of the hydrogen sulfide (H₂S). The surface morphology of the fabric was determined using scanning electron microscope and energy-dispersive X-ray spectroscopy. The optical properties of the fabric were evaluated by measuring the variation in the blue value of an RGB sensor. The fabric showed a significant color change, high linearity (R² : 0.98256), and fast response time (< 1.0 s) when exposed to H₂S. This is because the sensor is highly porous and permeable to the gas. The fabric can not only be used as a hydrogen sulfide sensor but also be used to detect and prevent H₂S influx using sticky tape on pipelines.

• Journal of Sensor Science and Technology
• /
• v.27 no.4
• /
• pp.237-241
• /
• 2018

The real-time enrichment and detection of pathogens are serious issues and rapidly evolving field of research because of the ability of these pathogens to cause infectious diseases. In general, bacterial detection is accomplished by conventional colony counting or by polymerase chain reaction (PCR) after DNA extraction. As colony counting requires considerable time to cultivate, PCR is an attractive method for rapid detection. A small number of pathogens can cause diseases. Hence, a pretreatment process, such as enrichment is essential for detecting bacteria in an actual environment. Thus, in this study, we developed a microfluidic chip capable of performing rapid enrichment of bacteria and the extraction of their genes. A lectin, i.e., Concanavalin A (ConA), which shows binding affinity to the surface of most bacteria, was coated on the surface of magnetic particles to nonspecifically capture bacteria. It was subsequently concentrated through magnetic forces in a microfluidic channel. To lyse the captured bacteria, magnetic particles were irradiated by a wavelength of 532nm. The photo-thermal effect on the particles was sufficient for extracting DNA, which was consequently utilized for the identification of bacteria. Our device will help monitor the existence of bacteria in various environmental situations such as water, air, and soil.

• 전자공학회논문지 IE
• /
• v.45 no.3
• /
• pp.27-35
• /
• 2008

In this paper, we propose a minute signal detection algorithm for a development of optical analyzer, using the non-dispersive infrared method with multi gas filter correlation wheel, that can measure various environmental air-pollution materials (CO, SO2, NOx, etc.) in real-time. The MCT(mercury cadmium telluride) sensor can detect minute signals those show and absorption characteristic of each environmental pollution materials. In the proposed method, a corresponding data of each environmental pollution materials can be separated by an external trigger and threshold values in the measured continuous signals.