• 한국산학기술학회논문지
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• 제5권1호
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• pp.87-92
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• 2004

This review focuses on the developed and the being developed environmental sensors in particular biological sensors. As well as discussing the classification and some main principles, presenting current trend of the environmental sensors is given. Two main categories are immunosensors and catalytic sensors. In addition to those. DNA or RNA sensors or protein based sensors are discussed. Some crucial examples of the applications of such sensors are given to show how the sensor technology it used for environmental and biological monitoring, biomarkers of exposure.

• 한국가스학회지
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• 제20권2호
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• pp.66-71
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• 2016

현재 산업단지에는 수많은 센서로부터 얻는 정보를 이용해 누출 발생지역을 감지 감시하고 있다. 그러나 화학물질 누출사고는 꾸준히 발생하고 있으며, 때에 따라 다량의 화학물질이 누출되는 경우에는 큰 피해가 발생하고 있다. 이때 중요하게 작용하는 센서 배치가 현재까지는 과거의 경험을 통하여 그 결정이 이루어지거나, 또는 센서제작 업체에서 제시하는 가이드를 통하여 설치되고 있다. 따라서 본 연구에서는 화학물질 누출이 일어났을 때 빠른 감지 및 대응을 위해 가장 중요한 요소인 센서 배치 최적화 방법론을 제시하였다. 특히 공정구조에 따른 누출흐름이 미반영된 상태에서 초기 배치 최적화를 위해 센서 개수 최소화 측면과 화학물질감지확률 측면으로 나누어 일반적으로 사용할 수 있는 수식을 제시하였다. 제시된 방법은 간단한 누출 시나리오를 이용하여 검증을 진행하였고, 이를 통해 각 공정의 안전성 목표치를 성취함으로써 안전한 공정 운영이 가능하도록 하였다.

• 센서학회지
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• 제17권2호
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• pp.143-146
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• 2008

Polymer-coated film SAW sensors have been fabricated and their sensing properties for toxic chemicals have been extensively investigated. Four types of the toxic chemical compounds of hydrogen cyanide(AC), carbonyl dichloride(CG), pinacolyl methylfluorophosphonate(GD), 2,2'-dichlorodiethylthio ether(HD) were used as target gases. SAW sensors using five different kinds of polymers were used to detect toxic chemicals and their gas sensing characteristics were investigated. The polymers used as the sensing materials were polyisobutylene(PIB), polyepichlorohydrin(PECH), polydimethylsiloxane(PDMS), polybutadiene(PBD) and polyisoprene(PIP). The recommendable mixing ratio of PIB, PECH, PDMS, PBD and PIP to solvents were 1:30, 1:40, 1:10, 1:30 and 1:30, respectively. The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.

• 센서학회지
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• 제25권4호
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• pp.291-296
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• 2016

The ideal chemical sensor must show the similar result under the same condition for accurate measurement of gases regardless of time. However, the actual responses of chemical sensors have been shown the lacks of repeatability and reproducibility because of the drift which has been caused by aging and pollution of the sensor and the environment change such as temperature and humidity. If the problems are not properly taken into considerations, the stability and reliability of the system using chemical sensors would be decreased. In this paper, we analyzed the sensor's drift and applied the three different compensation methods(DWT( Discrete Wavelets Transform), Baseline Manipulation, Internal Normalization) for reducing the effects of the drift in order to improve the stability and the reliability of short term of the chemical sensors. And in order to compare the results of the methods, the standard deviation was used as a criterion. The sensor drift was analyzed by a trend line graph. We applied the three methods to the successive data measured for three days and compared the results. As a result of comparison, the standard deviation of DWT showed lowest value. (Before compensation: 7.1219, DWT: 1.3644, Baseline Manipulation: 2.5209, Internal Normalization: 3.1425).

• 센서학회지
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• 제20권6호
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• pp.428-433
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• 2011

We report on the building of a micro sensor array based on typical semiconductor fabrication processes aimed at monitoring selectively a specific gas in ambient of other gases. Chemical sensors can be applied for an electronic nose and/or robots using this technique. Microsensor array was fabricated on the same chip using 0.6${\mu}m$ CMOS technology, and unique gas sensing patterns were obtained by principal component analysis from the array. $SnO_2$/Pt sensor for CO gas showed a high selectivity to buthane gas and humidity. $SnO_2$ sensor for hydrogen gas, however, showed a low selectivity to CO and buthane gas. We can obtain more distinguishable patterns that provide the small sensing deviation(the high seletivity) toward a given analyte in the response space than in the chemical space through the specific parameterization of raw data for chemical image formation.

• 동력기계공학회지
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• 제13권1호
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• pp.65-71
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• 2009

To address the need for new intelligent sensing, this paper introduces nano sensors made of carbon nanotube (CNT) composites and presents their preliminary experiments. Having smart material properties such as piezoresistivity, chemical and bio selectivity, the nano composite can be used as smart electrodes of the nano sensors. The nano composite sensor can detect structural deterioration, chemical contamination and bio signal by means of its impedance measurement (resistance and capacitance). For a structural application, the change of impedance shows specific patterns depending on the structural deterioration and this characteristic is available for an in-situ multi-functional sensor, which can simultaneously detect multi symptoms of the structure. This study is anticipated to develop a new nano sensor detecting multiple symptoms in structural, chemical and bio applications with simple electric circuits.

• 센서학회지
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• 제31권2호
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• pp.79-84
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• 2022

Self-powered sensors play an important role in everyday life, and they cover a wide range of topics. These sensors are meant to measure the amount of relevant motion and transform the biomechanical activities into electrical signals using triboelectric nanogenerators (TENGs) since they are sensitive to external stimuli such as pressure, temperature, wetness, and motion. The present advancement of TENGs-based self-powered wearable, implantable, and patchable sensors for healthcare monitoring, human body motion, and medication delivery systems was carefully emphasized in this study. The use of TENG technology to generate electrical energy in real-time using self-powered sensors has been the topic of considerable research among various leading scholars. TENGs have been used in a variety of applications, including biomedical and healthcare physical sensors, wearable devices, biomedical, human-machine interface, chemical and environmental monitoring, smart traffic, smart cities, robotics, and fiber and fabric sensors, among others, as efficient mechanical-to-electric energy conversion technologies. In this evaluation, the progress accomplished by TENG in several areas is extensively reviewed. There will be a discussion on the future of self-powered sensors.

• Transactions on Electrical and Electronic Materials
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• 제13권2호
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• pp.78-84
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• 2012

An in-situ optical monitoring method for real-time process monitoring of electrochemical copper deposition (CED) is presented. Process variables to be controlled in achieving desired process results are numerous in the CED process, and the importance of the chemical bath conditions cannot be overemphasized for a successful process. Conventional monitoring of the chemical solution for CED relies on the pH value of the solution, electrical voltage level for the reduction of metal cations, and gravity measurement by immersing sensors into a plating bath. We propose a nonintrusive optical monitoring technique using three types of optical sensors such as chromatic sensors and UV/VIS spectroscopy sensors as potential candidates as a feasible optical monitoring method. By monitoring the color of the plating solution in the bath, we revealed that optically acquired information is strongly related to the thickness of the deposited copper on the wafers, and that the chromatic information is inversely proportional to the ratio of $Cu$ (111) and {$Cu$ (111)+$Cu$ (200)}, which can used to measure the quality of the chemical solution for electrochemical copper deposition in advanced interconnection technology.

• Bulletin of the Korean Chemical Society
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• 제24권4호
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• pp.514-516
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• 2003

• 센서학회지
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• 제30권4호
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• pp.210-217
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• 2021

Gas sensors based on semiconducting metal oxides have attracted considerable attention for various applications owing to their facile, cheap, and small-scale manufacturing processes. Hematite (α-Fe₂O₃) is widely considered as a promising candidate for a gas-sensing material owing to not only its abundance in the earth's crust and low price but also its chemical stability and suitable bandgap energy. However, only a few studies have been performed in this direction because of the low gas response and sluggish response of hematite-based gas sensors. Nanostructures present a representative solution to both overcome these disadvantages and exploit the desirable features to produce high-performance gas sensors. However, several challenges remain for adopting gas sensors based on metal oxide nanostructures, such as improving cost efficiency and facilitating mass production. This review summarizes the recent studies on gas sensors based on hematite nanostructures. It also provides useful insights into various strategies for enhancing the gas-sensing properties of gas sensors based on hematite nanostructures.