• Nuclear Engineering and Technology
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• 제1권1호
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• pp.5-16
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• 1969

음전극을 가진 구형 가스 채집 전리함을 사용한 가스냉각 발전로 핵연료 피복파열에 관한 검출기술의 새로운 설계에 대한 연구이다. 설계를 위한 이론적인 계산결과에 의하면 이 설계된 시스템은 실지응용이 가능하고 1 $\textrm{cm}^2$ 크기의 핵연료 피복파열을 쉽게 검출할 수 있다는 것이 입증되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.905-910
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• 1991

This paper presets a leakage detection method based on modeling the leakage in pipeline systems. For gas pipeline systems, a method based on the state space model is suggested. For liquid pipeline systems, an experiment based on the static model equation was performed. In the experiment, it was possible to detect the leak and to diagnosis the leak situation within the error of .+-.3%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.243-244
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• 2013

Over the past 15 years, several groups have incorporated radio-frequency quadrupole (RFQ) based instruments before the accelerator in accelerator mass spectrometry (AMS) systems for ion-gas interactions at low kinetic energy (＜40 eV). Most AMS systems arebased on a tandem accelerator, which requires negative ions at injection. Typically, AMS sensitivity abundance ratios for radioactive-to-stable isotope are limited to Xr/Xs ＞10^-15, and the range of isotopes that can be analyzed is limited because of theneed to produce rather large negative ion beams and the presence of atomic isobaric interferences after stripping. The potential of using low-kinetic energy ion-gas interactions for isobar suppression before the accelerator has been demonstrated for several negative ion isobar systems with a prototype RFQ system incorporated into the AMS system at IsoTrace Laboratory, Canada (Ontario, Toronto). Requisite for any such RFQ system applied to very rare isotope analysis is large transmission of the analyte ion. This requires proper phase-space matching between the RFQ acceptance and the ion beam phase space (e.g. 35 keV, ${\varphi}3mm$, +-35 mrad), and the ability to control the average ion energy during interactions with the gas. A segmented RFQ instrument is currently being designed at Korea Institute for Science and Technology (한국과학기술연구원, KIST). It will consist of: a) an initial static voltage electrode deceleration region, to lower the ion energy from 35 keV down to ＜40 eV at injection into the first RFQ segment; b) the segmented quadrupole ion-gas interaction region; c) a static voltage electrode re-acceleration region for ion injection into a tandem accelerator. Design considerations and modeling will be discussed. This system should greatly lower the detection limits of the 6 MV AMS system currently being commissioned at KIST. As an example, current detection sensitivity of 41Ca/Ca is limited to the order of 10^-15 while the 41Ca/Ca abundance in modern samples is typically 41Ca/Ca~10^-14 - 10^-15. The major atomic isobaric interference in AMS is 41K. Proof-of-principal work at IsoTrace Lab. has demonstrated that a properly designed system can achieve a relative suppression of KF3-/41CaF3- ＞4 orders of magnitude while maintaining very high transmission of the 41CaF3- ion. This would lower the 41Ca detection limits of the KIST AMS system to at least 41Ca/Ca~10^-19. As Ca is found in bones and shells, this would potentially allow direct dating of valuable anthropological archives and archives relevant to our understanding of the most pronounced climate change events over the past million years that cannot be directly dated with the presently accessible isotopes.

• 조명전기설비학회논문지
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• 제25권2호
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• pp.96-102
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• 2011

There are many problems with the fire detection devices being used in currently, because it is difficult to find location of the source of fire and determine where devices are working or not. In this paper, we proposed fire detection and rescue system using wireless sensor network that can be real-time monitoring and determine safe exit. Fire detection and rescue system based on ubiquitous sensor network can know exactly source of fire and help determine rescue tactics using sensing data from wireless sensor nodes. Transmitted wirelessly in real-time thermal sensor and gas sensor information to analyze the GUI to monitor the status information output to the screen by use of a system implemented in everyday life, looked at the possibility.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.376-386
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• 2015

MOFs(Metal-Organic Frameworks) are new kinds of materials comprised of metal ions and functional organic ligands, and have large pores in its rigid structures which give the materials various functionalities, including gas absorption, separation, drug delivery etc. Recently photoluminescence properties of MOFs and possibilities of its application to high explosive sensing technologies are drawing attentions from scientists and engineers, because these methods are simple, cheap and easy to perform detection operations. In this article the author reviews the mechanisms of photoluminescence of MOFs, the detection methods of high explosives using MOFs and recent research progresses based on the papers published mainly during last 10 years.

• Smart Structures and Systems
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• 제16권1호
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• pp.213-222
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• 2015

Early detection and precise location of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. In the past few years, acoustic emission (AE) techniques have demonstrated to be an excellent tool for on-line leakage detection. Regarding the multi-mode and frequency dispersion characteristics of AE signals propagating along a pipeline, the direct cross-correlation technique that assumes the constant AE propagation velocity does not perform well in practice for acoustic leak location. This paper presents an improved cross-correlation method based on wavelet transform, with due consideration of the frequency dispersion characteristics of AE wave and the contribution of different mode. Laboratory experiments conducted to simulate pipeline gas leakage and investigate the frequency spectrum signatures of AE leak signals. By comparing with the other methods for leak location identification, the feasibility and superiority of the proposed method are verified.

• 센서학회지
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• 제32권3호
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• pp.180-186
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• 2023

Test devices can perform various functions, such as research on detection targets, sensors that detect detection targets, combined products containing sensors, and certification for the launch of combined products. However, the scope of use of test devices is limited because they perform only a single role or could only serve a particular purpose in the past. Therefore, studies on test devices that can perform various functions, such as research on detection targets, sensors that detect detection targets, combined products containing sensors, and certification for the release of combined products are necessary. Accordingly, this study proposes a test device that can increase the scope of use in the technical field of electric fires. In addition, we examine various outcomes of the proposed test device.

• 한국재료학회지
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• 제23권9호
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• pp.477-482
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• 2013

We investigated the detection properties of nitrogen monoxide (NO) gas using transparent p-type $CuAlO_2$ thin film gas sensors. The $CuAlO_2$ film was fabricated on an indium tin oxide (ITO)/glass substrate by pulsed laser deposition (PLD), and then the transparent p-type $CuAlO_2$ active layer was formed by annealing. Structural and optical characterizations revealed that the transparent p-type $CuAlO_2$ layer with a thickness of around 200 nm had a non-crystalline structure, showing a quite flat surface and a high transparency above 65 % in the range of visible light. From the NO gas sensing measurements, it was found that the transparent p-type $CuAlO_2$ thin film gas sensors exhibited the maximum sensitivity to NO gas in dry air at an operating temperature of $180^{\circ}C$. We also found that these $CuAlO_2$ thin film gas sensors showed reversible and reliable electrical resistance-response to NO gas in the operating temperature range. These results indicate that the transparent p-type semiconductor $CuAlO_2$ thin films are very promising for application as sensing materials for gas sensors, in particular, various types of transparent p-n junction gas sensors. Also, these transparent p-type semiconductor $CuAlO_2$ thin films could be combined with an n-type oxide semiconductor to fabricate p-n heterojunction oxide semiconductor gas sensors.

• 한국정보전자통신기술학회논문지
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• 제14권5호
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• pp.369-374
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• 2021

최근에 건설되는 아파트는 주방이 빌트인 방식으로 만들어지므로 가스 호스가 싱크대 내부에 보이지 않게 만들어지므로 가스가 누출될 경우 싱크대 내부에 축적되어 가스 폭발로 이어질 수 있는 위험한 방식이다. 본 연구에서는 가스레인지와 중간밸브 사이에 연결된 호스가 싱크대 내부에 있어 가스 누출 검사를 할 수 없는 구조로 되어 있어 압력센서를 이용하여 가스누출을 검사를 쉽게 할 수 있는 밸브 시스템 연구하였다. 압력 측정 방법은 중간밸브와 가스레인지를 연결하는 호스의 압력을 측정하여 I2C통신 방식으로 데이터를 수집·분석 할 수 있도록 진행하였다. 또한 가정에 공급되는 가스압력계산은 대기압력에 가스계량기의 입구에서 가스게이지 압력 평균값 22.46mbar를 더 한 값으로 계산된 것에 대한 대기 압력 오차에 대한 규명 및 미세한 가스 누출 감지를 할 수 있도록 밸브 시스템을 개발하였다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2001년도 추계학술발표회 논문집
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• pp.58-68
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• 2001

Microbiologically influenced corrosion (MIC) of carbon steel gas pipeline in soil environments was investigated at field and laboratory MIC is very severe corrosion and it is not easy to distinguish this corrosion from Inorganic corrosion because of its localized, pitting-type character Therefore, it is important to provide proper assessment techniques for the prediction, detection, monitoring and mitigation of MIC. It is possible to predict the MIC risk, i.e., the activity of sulfate-reducing bacteria (SRB) through the analysis of soil environments. Chemical, microbiological and surface analysis of corrosion products and metal attacked could reveal the possibility of the occurrence of MIC. Various electrochemical and surface analysis techniques could be used for the study of MIC. Among these techniques, thin-film electrical resistance (ER) type sensors are promising to obtain localized corrosion rate of MIC induced by SRB. It is also important to study the effect of cathodic protection (CP) on the MIC In case of coated pipeline, the relationship between coating disbondment and the activity of SRB beneath the disbanded coating is also important.