• 한국안전학회지
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• 제32권2호
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• pp.7-13
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• 2017

An experimental study was conducted to identify the quantitative measurement bias for the bare-bead thermocouple (TC), which was widely used for measuring temperature in fire experiments. To this end, an apparatus could be controlled individually gas flow rate, preheating temperature and incident radiative heat flux was developed to simulate the thermal environments of fire. A relative measurement bias of bare-bead TC was evaluated with the comparison of double-shield aspirated TC. As a result, the relative measurement bias of bare-bead TC was gradually increased with the increase in radiative heat flux with constant gas temperature. The relative bias was also significantly increased with the decrease in gas temperature. Quantitatively, at the gas temperature of $20^{\circ}C$, the bare-bead TC had the relative bias of approximately 400% with the radiative heat flux of $20kW/m^2$ corresponding to thermal radiation level of the flashover. The present study was intend to provide fire researchers with methodologies for the reanalyses of temperature measured using bare-bead TC, radiation corrections, and validation of fire modeling.

• 한국안전학회지
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• 제32권2호
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• pp.14-20
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• 2017

A numerical study was conducted to identify the predictive performance for the bare-bead thermocouple (TC) using FDS (Fire Dynamics Simulator) in simulated thermal environments of fire. A relative prediction bias of TC temperature calculated from reverse-radiation correction by FDS was evaluated with the comparison of previous experimental data. As a result, it was identified that the TC temperatures predicted by FDS were lower than the temperatures measured by bare-bead TC for the ranges of heat flux and gas temperature considered. The relative prediction bias of TC temperature by FDS was gradually increased with the increase in radiative heat flux and also significantly increased with the decrease in the gas temperature. Quantitatively, at the gas temperature of $20^{\circ}C$, the TC temperature predicted by FDS had the relative bias of approximately -20% with the radiative heat flux of $20kW/m^2$ corresponding to thermal radiation level of the flashover. It is predicted from the present study that more accurate validation of fire modeling will be possible with the quantitative prediction bias occurred in the process of reverse-radiation correction of temperature predicted by FDS.

• Wind and Structures
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• 제31권4호
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• pp.321-334
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• 2020

Engineering type tropical cyclone (TC) wind field models are used to estimate TC wind hazard. Some of the models are well-calibrated using observation data, while others are not extensively compared and verified. They are all proxies to the real TC wind fields. The computational effort for their use differs. In the present study, a comparison of the predicted wind fields is presented by considering three commonly used models: the gradient wind field model, slab-resolving model, and a linear height-resolving model. These models essentially predict the horizontal wind speed at a different height. The gradient wind field model and linear height-resolving model are simple to use while the nonlinear slab-resolving model is more compute-intensive. A set of factors is estimated and recommended such that the estimated TC wind hazard by using these models becomes more consistent. The use of the models, including the developed set of factors, for estimating TC wind hazard over-water and over-land is presented by considering the historical tracks for a few sites. It is shown that the annual maximum TC wind speed can be adequately modelled by the generalized extreme value distribution.

• 정보관리연구
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• 제35권3호
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• pp.51-74
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• 2004

ISO/TC46은 ISO 전문위원회 중에서도 가장 오래되었으며, 특히 도서관, 도큐멘테이션 및 정보센터, 색인 및 초록서비스, 문서기록, 정보학 및 출판 등과 관련된 표준화 활동을 하고 있다. 그 산하에는 모두 SC4, SC8, SC9, SC11의 4개 분과위원회가 있으며, 이들의 최근 활동을 분석함으로써 '정보와 도큐멘테이션'에 대한 국제표준화 흐름을 개략적으로 살펴보았다. 그리고 이 가운데 특히 SC9의 정보식별을 위한 표준화활동과 관련하여 ISBN, ISSN, ISMN, ISRN, ISRC, ISAN, ISWC, ISTC 등 8개의 국제표준번호들의 특성과 식별체계를 비교 분석한 후 <표 1>에 나타내었으며, 이들 번호간에 상호 관련성을 <그림 1>에 제시하였다. 또한 국제표준번호제도에 있어 전자자료에 대한 번호부여, 구성부분에 대한 번호부여, 작품에 대한 번호부여 등의 문제점과 전망에 대해 논급하였다.

• Asia-Pacific Journal of Atmospheric Sciences
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• 제54권4호
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• pp.575-585
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• 2018

In the case study of this paper, sensitivity experiments are carried out using the mesoscale non-hydrostatic Weather Research and Forecasting (WRF) model to investigate the impact of tropical cyclone (TC) Soudelor (2003) on the East Asian subtropical upper-level jet (EASJ) before TC Soudelor transformed into an extratropical cyclone. The physical mechanism for changes in the EASJ intensity and position caused by TC Soudelor is explored. Results indicate that TC Soudelor would warm the air in the middle and upper troposphere over the Japan Sea and the adjacent areas through stimulating northward propagating teleconnection pattern as well as releasing large amounts of latent heat, which led to increase (decrease) the meridional air temperature gradient to the south (north) below the EASJ axis. As a result, the geopotential height abnormally increased in the upper troposphere, resulting in an anomalous anticyclonic circulation belt along the EASJ axis. Correspondingly, the westerly winds to the north (south) of the EASJ axis intensified (weakened) and the EASJ axis shifted northward by one degree. The case study also suggests that before the extratropical cyclone transition of TC Soudelor, the TC activities had exerted significant impacts on the EASJ through thermodynamic processes.

• 대한의생명과학회지
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• 제29권4호
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• pp.280-286
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• 2023

In humic substances, fulvic acid (FA) is a subclass of diverse compounds known as humic substances, which are by-products of organic degradation from microorganisms. FA can suppress the proliferation of tumor cells. Despite numerous studies, the exact mechanism for the various effects of FA is not clearly understood. Based on results demonstrating anti-proliferation effects on human cancer, we investigated whether FA has similar effects on lung cancer in this study. Firstly, the anti-cancer effect of FA in pulmonary epithelial tumor cell lines (TC-1 cells) was examined by confirming its inhibitory effect on the cell proliferation of TC-1 cells. TC-1 cell proliferation was reduced by FA on a dose-dependent and time-dependent manner. After 24 hours of FA treatment, cell morphological changes such as cell volume decrease, non-adherence and increased number of apoptotic cells were clearly observed. In addition, FA induced a DNA ladder pattern by increased of DNA fragments in TC-1 cells. In the intracellular regulatory pathway by FA, we confirmed that FA induced the reduction of the anti-apoptotic protein, Bcl-2 protein levels. These results indicate that FA has anticancer effect by inducing intracellular apoptotic pathway. Further research on the mechanism of anticancer effects will be basic data for the development of potential anticancer drugs.

• 대한전자공학회논문지TC
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• 제41권11호
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• pp.33-38
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• 2004

본 논문에서는 시간분산 통신로에 주파수선택성 페이딩과 다중경로 페이딩을 극복하기 위해서, 격자부호 변조와 OFDM을 결합한, 격자부호 직교주파수분할 다중통신방식(TC-OFDM) 시스템의 성능을 분석한다. 시간분산 통신로를 대상으로 부호율 2/3인 격자부호 8DPSK- OFDM의 BER 성능을 모의실험하고 분석한다. OFDM의 여러 반송파 수에 대한 격자부호의 설계를 논의한다. 실험결과, BER 10/sup -3/에서 TC-OFDM 시스템은 부호화를 하지 않은 OFDM 시스템에 비해서 6 dB 부호이득을 얻을 수 있음을 알았다.

• 대한핵의학회지
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• 제27권2호
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• pp.277-284
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• 1993

$^{99m}Tc$-MAG3는 세뇨관 배설을 하는 신장 기능 영상용 방사성의 약품으로서, 가운데 $^{99m}Tc$이 있고 1개의 유황과 3개의 질소가 아래쪽 면에 정사각형으로 배치되고 정점에 산소가 위치한 4각 피라미드형을 하고 있다. 그러나 시판되는 신장 영상용 MAG3는 반응성이 강한 -SH기에 의한 부산물 생성을 방지하기 위해 benzoyl기로 보호되어 있으므로 보통 조건으로는 잘 표지되지 않고 10분 정도 끓여주어야 한다. 본 실험에서는 실온에서도 benzoyl기를 잘 끊어지게 하는 이미다졸, 아고마틴, 괴리딘등과 같은 염기성 촉매제를 가하고 여러가지 PH에서 실온에서 반응시켜 본 결과, benzoyl기가 끊어지면서 $^{99m}Tc$과 -SH기가 반응하는 첫번째 반응이 일어난 후에도 산성에서 약알칼리성 범위에서는 중간체가 상당량 생성되고 알칼리성 (pH 10.5)이 되어야 최종 산물로 재빨리 넘어가는 것을 발견하였다. 또한 glucarate, medronate, phthalate, acetate 등 여러가지 다른 transchelating agent를 사용하여 같은 반응을 시킨 후에도 생성된 중간체의 HPLC 피크가 같은 retention time (Rt)을 보이는 것으로 보아 이 중간체의 화학구조내에는 transchelating agent를 포함하지 않는 것으로 보인다. 최종 생성물과 중간체의 ImM 시트테인 용액 중에서의 안정도 시험을 하여 본 결과 최종 생성물은 매우 안정하나 중간체는 불안정한 것을 발견하였다.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.647-658
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• 1993

The purpose of this study is to examine the influence of 5% tetracycline(Tc) gel on healing of gingival tissue and change of diseased root surface when used with nonsurgical procedure. 7 patients with advanced periodontitis were received thorough scaling and root planning, followed by saline irrigation on 10 randomly selected control teeth and Tc gel application for 5 minutes with specifically designed plastic instrument of 10 test teeth in contralateral side. At 0, 1, 7, 14, and 21 days after treatment, biopsy and extraction were carried out. At day 7, Tc group showed decreased inflammation and delayed proliferation of pocket epithelium in comparison with control group which was continued for all experimental days. Scanning electron microscopic finding revealed demineralized and cleaned root surface with exposed dentinal tubules in Tc gel group. In the present study, clinically successful result is expected with combined use of nonsurgical periodontal therapy and intrapocket application of Tc gel.

• 대한방사성의약품학회지
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• 제5권1호
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• pp.3-10
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• 2019

The activities per volume of $^{188}Re$ and $^{99m}Tc$ from their generators are dependent on the specific activity of their mother nuclides $^{188}W$ and $^{99}Mo$ respectively. After a particular lapse of time, the eluted RI activity is exponentially reduced and thus cannot satisfy the needs of clinical application. The purpose of this study is to develop a $^{188}Re$ and $^{99m}Tc$ concentration device with a compact size that can extend the period of use as well as conveniently concentrate the RI. We designed the concentration module by including two-different check valves that do not required any manual on-off operations. In these concentration process, cation exchange resin embedded with Ag and anion exchange resins were used. After completing the concentrating step, the recovering yield was identified to be more than 93% for $^{188}Re$ generators and 88% for $^{99m}Tc$ generators. Moreover, all these procedures were done within 5 min.