• Title/Summary/Keyword: field screening

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Comparison of isoBOC derivatives, TBDMS derivatives, with US EPA Method in the sensitivity of Alkylphenols, Chlorophenols, and Bisphenol A potential field-screening applications of GC/MS-SIM

  • Kim, Hyub;Hong, Jong-Ki;Kim, Yong-Hwa;Kim, Kyoung-Rae
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.235.2-236
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    • 2002
  • The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison: EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. (omitted)

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Ion charge in captivity in a nanotube-doped liquid-crystal cell (?)

  • Lee, Wei;Chen, Hui-Yu
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1609-1612
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    • 2006
  • Transient currents were measured in nematic liquid-crystal cells with and without doping of multiwalled carbon nanotubes. Comparative results suggest that the field-screening effect induced by the adsorbed charge is substantially suppressed by the carbon-nanotube dopant, leading to a reduction of the driving voltage and improved performance of display properties.

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A Hidden Key to COVID-19 Management in Korea: Public Health Doctors

  • Choi, Sejin
    • Journal of Preventive Medicine and Public Health
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    • v.53 no.3
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    • pp.175-177
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    • 2020
  • Public health doctors of Korea contributed significantly to massive coronavirus disease 2019 (COVID-19) testing. They were immediately dispatched to epicenters of the COVID-19 pandemic, and have run tests at screening centers, airport quarantines and hospitals. However, their expertise from in-field experience has been often neglected. It is time to reorganize public health doctor system to better prepare for future epidemics. Transforming and strengthening their roles as public health experts through systematic training is crucial.

Properties of Magnetic Resistance Device in Superconductor Materials (자기 저항소자의 특성)

  • Lee, Sang-Heon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.283-284
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    • 2008
  • The magnetic flux is generated by a vortex current which circulates around the vortex with a sense of rotation opposite to that of the diamagnetic screening surface current. When the external magnetic field was applied to the superconductor magnetometer, some regions of the magnetic sensor will be destroyed, especially the weak link regions and the defect regions. The destroyed regions will be increased with the increasing of the magnetic flux.

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Implementation of a Portable Electronic Nose System for Field Screening (필드 스크린을 위한 휴대용 전자코 시스템의 구현)

  • Byun, Hyung-Gi;Lee, Jun-Sub;Kim, Jeong-Do
    • Journal of Sensor Science and Technology
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    • v.13 no.1
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    • pp.41-46
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    • 2004
  • There is currently much interest in the development of instruments that emulate the senses of humans. Increasingly, there is demand for mimicking the human sense of smell, which is a sophisticated chemosensory system. An electronic nose system is applicable to a large area of industries including environmental monitoring. We have designed a protable electronic nose system using an array of commercial chemical gas sensors for recognizing and analyzing the various odours. In this paper, we have implemented a portable electronic nose system using an array of gas sensors for recognizing and analyzing VOCs (Volatile Organic Compounds) in the field. The accuracy of a portable electronic nose system may be lower than an instrument such as GC/MS (Gas Chromatography/Mass Spectrometer). However, a portable electronic nose system could be used on the field and showed fast response to pollutants in the field. Several different algorithms for odours recognition were used such as BP (Back-Propagation) or LM-BP (Levenberq-Marquardt Back-Propagation). We applied RBF (Radial Basis Function) Network for recognition and quantifying of odours, which has simpler and faster compared to the previously used algorithms such as BP and LM-BP.

Development of new agrochemicals by quantitative structure-activity relationship (QSAR) methodology. III. 3D QSAR methodologies and computer-assisted molecular design (CAMD) (정량적인 구조-활성상관 (QSAR) 기법에 의한 새로운 농약의 개발. III. 3D QSAR 기법들과 컴퓨터를 이용한 분자설계(CAMD))

  • Sung, Nack-Do
    • The Korean Journal of Pesticide Science
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    • v.7 no.1
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    • pp.1-11
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    • 2003
  • Acoording to improvement of HTOS (high throughput organic synthesis) and HTS (high throughput screening) technique, the CoMFA (comparative molecular field analysis), CoMSIA (comparative molecular similarity indeces analysis) and molecular HQSAR (hologram quantitative structure-activity relationship) analysis techniques as methodology of computer assisted molecular design (CAMD) were introduced generally and summarized for some application cases.

High-temperature superconductors for NMR/MRI magnets:opportunities and challenges

  • Iwasa, Yukikazu;Bascunan, Juan;Hahn, Seungyong;Yao, Weijun
    • Superconductivity and Cryogenics
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    • v.11 no.2
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    • pp.23-29
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    • 2009
  • The unique features of HTS offer opportunities and challenges to a number of applications. In this paper we focus on NMR and MRI magnets, illustrating them with the NMR/MRI magnets that we are currently and will shortly be engaged: a 1.3 GHz NMR magnet, an "annulus" magnet, and an $MgB_2$whole-body MRI magnet. The opportunities with HTS include: 1) high fields (e.g., 1.3 GHz magnet); 2) compactness (annulus magnet); and 3) enhanced stability despite liquid-helium-free operation ($MgB_2$whole-body MRI magnet). The challenges include: 1) a large screening current field detrimental to spatial field homogeneity (e.g., 1.3 GHz magnet); 2) uniformity of critical current density (annulus magnet); and 3) superconducting joints ($MgB_2$magnet).

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Development of Reference Scenarios Based on FEPs and Interaction Matrix for the Near-surface LILW Repository

  • Lee, Dong-Won;Kim, Chang-Lak;Park, Joo-Wan
    • Nuclear Engineering and Technology
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    • v.33 no.5
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    • pp.539-546
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    • 2001
  • Systematic procedure of developing radionuclide release scenarios was established based on FEP list and Interaction Matrix for near-surface LILW repository. FEPs were screened by experts'review in terms of domestic situation and combined into scenarios on the basis of Interaction Matrix analysis. Under the assumption of design scenario, The system domain was divided into three sections: Near-field, Far-field and Biosphere. Sub-scenarios for each section were developed, and then scenarios for entire system were built up with sub-scenarios of each section. Finally, sixteen design scenarios for near-surface repository were evaluated A reference scenario and other noteworthy scenarios were selected through experts'scenario screening.

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Two-step approaches for effective bridge health monitoring

  • Lee, Jong Jae;Yun, Chung Bang
    • Structural Engineering and Mechanics
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    • v.23 no.1
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    • pp.75-95
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    • 2006
  • Two-step identification approaches for effective bridge health monitoring are proposed to alleviate the issues associated with many unknown parameters faced in real structures and to improve the accuracy in the estimate results. It is suitable for on-line monitoring scheme, since the damage assessment is not always needed to be carried out whereas the alarming for damages is to be continuously monitored. In the first step for screening potentially damaged members, a damage indicator method based on modal strain energy, probabilistic neural networks and the conventional neural networks using grouping technique are utilized and then the conventional neural networks technique is utilized for damage assessment on the screened members in the second step. The effectiveness of the proposed methods is investigated through a field test on the northern-most span of the old Hannam Grand Bridge over the Han River in Seoul, Korea.

Neural network algorithm for VOC gas recognition and concentration estimation at field screen using E-Nose System

  • Kim, Jeong-Do;Byun, Hyung-Gi;Ham, Yu-Kyung;Lee, Jun-Sub;Shon, Won-Ryul;Heo, Nam-Up
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.61.3-61
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    • 2001
  • Field screening for pollutants has been a target of instrumental development for number of years. An electronic nose can be of substantial benefit to rapidly localize the spatial extent of a pollution or to find pollutant source. Although an electronic nose cannot separate complex composition into the whole spectrum of present volatile organic compound(VOC) in pollutants such as Gas chromatography(GC), qualitative and semi-quantitative chemical characterizations are rapidly available on site at a low cost using the optimum sensory system and pattern recognition algorithm based on neural network.

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