• 한국멀티미디어학회논문지
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• 제12권11호
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• pp.1692-1700
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• 2009

본 논문에서는 메쉬 법선 벡터들의 방향 분포를 3차원 모델의 특징 기술자로 제안한다. 특징 기술자로써 요구되는 회전 불변을 주성분 분석법(PCA)으로 처리하고 잡음첨가에 강건하도록 메쉬 간략화를 수행한다. 표면적이 작은 면에 대한 정보가 특징 기술자를 구성하는데 더 적게 반영되도록 법선 벡터의 분포를 각 다각형의 면적에 비례하게 표본을 뽑아 법선 벡터에 가중치를 적용하고 보간하여 변별력을 높인다. 모델간의 유사도는 특징 기술자의 거리를 정규화한 확률 밀도 히스토그램의 L1-norm으로 측정한다. 제안한 방법이 기존 방법에 비해 검색 순위 평균(ANMRR)으로 나타낸 검색 성능이 약 17.2%, 정량적 변별 척도로 나타낸 검색 성능이 최소 9.6%에서 최대 17.5%까지 향상되었음을 알 수 있었다.

• 한국가스학회지
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• 제24권3호
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• pp.40-46
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• 2020

텨셔리부틸퍼옥시말레이트(Tertbutylperoxymaleate : TBPM)는 인조대리석 제조에 사용되는 개시제 조성물의 원료로 유기과산화물의 일종이다. 본 연구에서는 시차주사열량계(DSC)를 이용하여 공기 및 질소 분위기에서 TBPM의 열분해특성을 평가하였다. TBPM은 반응 분위기와 관계없이 130 ℃ 이하에서 급격한 분해에 의한 발열을 나타냈다. 그리고 동적방법을 이용한 속도론적 평가에서 방법에 따라서 203~217 kJ/mol의 활성화에너지를 보였으며, Model-free 방법에 의한 분석에서는 118~232 kJ/mol의 활성화에너지를 갖는 것으로 평가되었다. 그리고 도출된 활성화에너지를 이용하여 24시간 이내에 최대발열속도에 도달하는 온도인 ADT₂₄는 (80~95) ℃로 평가되었다.

• 한국약용작물학회지
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• 제18권1호
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• pp.15-21
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• 2010

This study was conducted to investigate the effects of Lycii fructus and Astragalus membranaceus mixed extracts on immunomodulators and prevention in a streptozotocin-induced diabetes rat model. A total of 28 male rats were divided into four dietary groups and fed a commercial diet (A), commercial diet plus induced diabetes by a streptozotocin (STZ) injection (B), induced diabetes by STZ plus medicinal crop extracts(I&$H^{(R)}$) diet (C), and medicinal crop extracts (I&$H^{(R)}$) diet (D). Immunoblotting analyses revealed cytokine expression, and ELISA analyses revealed immunoglobulin E and nitric oxide production. As a results, the tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and inducible nitric oxide synthase (iNOS) as a inflammatory cytokine were decreased. Interleukin-6 (IL-6) and signal transducer and activation of transcription 3 (STAT3) cytokine related in diabetes expression through JAK/STAT3 pathway were also decreased. Furthermore, immunoglobulin E and nitric oxide production were decreased in the serum and lens, respectively. These results suggest that Lycii fructus and Astragalus membranaceus mixed extracts provide positive effects on immunomodulators and prevention in diabetes and eye disease complications.

• Smart Structures and Systems
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• 제13권2호
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• pp.281-303
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• 2014

In order to suppress the wind-induced vibrations of the Canton Tower, a pair of active mass driver (AMD) systems has been installed on the top of the main structure. The structural principal directions in which the bending modes of the structure are uncoupled are proposed and verified based on the orthogonal projection approach. For the vibration control design in the principal X direction, the simplified model of the structure is developed based on the finite element model and modified according to the field measurements under wind excitations. The AMD system driven by permanent magnet synchronous linear motors are adopted. The dynamical models of the AMD subsystems are determined according to the open-loop test results by using nonlinear least square fitting method. The continuous variable gain feedback (VGF) control strategy is adopted to make the AMD system adaptive to the variation in the intensity of wind excitations. Finally, the field tests of free vibration control are carried out. The field test results of AMD control show that the damping ratio of the first vibration mode increases up to 11 times of the original value without control.

• 한국약용작물학회지
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• 제18권4호
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• pp.224-230
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• 2010

This study was conducted to investigate anti-oxidative and inflammatory inhibition effects of green tea and dietary fiber mixture on liver of high fat diet-induced obese rats. 21 male rats were divided into 3 dietary groups and control group (A), high fat diet-induced group (B), and high fat (HF) diet-induced + EQ diet-$S^{(R)}$ diet group (C). Immunoblotting and RT-PCR analysis revealed protein expression, and anti-oxidant analysis revealed MDA (malondialdehyde), GSH (glutathione), and free DPPH radical. As a results, Body weight and food consumption were not significantly different between groups. The levels of MDA and GSH were lower in HF + $EQS^{(R)}$ group than in HF group. Also, the $EQS^{(R)}$ demonstrated to be more effective than HF group for a DPPH radicals scavenging activities. In addition, protein and mRNA level of TNF-$\alpha$ in HF + $EQS^{(R)}$ group showed relatively more potent pro-inflammatory activity inhibition compared to HF group. These results suggest that green tea mixture (EQ diet-$S^{(R)}$) provide positive effects on anti-oxidative and inflammatory inhibition effects on obese animal model or obesity related diseases.

• 대기
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• 제22권1호
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• pp.1-12
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• 2012

The Atmospheric motion vectors (AMVs) derived using infrared (IR) channel imagery of geostationary satellites have been utilized widely for real-time weather analysis and data assimilation into global numerical prediction model. As the horizontal resolution of sensors on-board satellites gets higher, it becomes possible to identify atmospheric motions induced by convective clouds ($meso-{\beta}$ and $meso-{\gamma}$ scales). The National Institute of Meteorological Research (NIMR) developed the high resolution visible (HRV) AMV algorithm to detect mesoscale atmospheric motions including ageostrophic flows. To retrieve atmospheric motions smaller than $meso-{\beta}$ scale effectively, the target size is reduced and the visible channel imagery of geostationary satellite with 1 km resolution is used. For the accurate AMVs, optimal conditions are decided by investigating sensitivity of algorithm to target selection and correction method of height assignment. The results show that the optimal conditions are target size of 32 km ${\times}$ 32 km, the grid interval as same as target size, and the optimal target selection method. The HRV AMVs derived with these conditions depict more effectively tropical cyclone OMAIS than IR AMVs and the mean speed of HRV AMVs in OMAIS is slightly faster than that of IR AMVs. Optimized mesoscale AMVs are derived for 6 months (Feb. 2010-Jun. 2010) and validated with radiosonde observations, which indicates NIMR's HRV AMV algorithm can retrieve successfully mesoscale atmospheric motions.

• 한국가스학회지
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• 제16권4호
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• pp.32-37
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• 2012

본 연구에서는 폭발사고가 반복되고 있는 마그네슘합금(Mg-Al alloy) 분진의 동종재해 예방대책을 위한 안전자료로 활용하기 위하여 폭발특성을 실험적으로 조사하고 화염전파속도를 추정하였다. 화염전파속도는 폭발과 압력 강도에 영향을 주지만 분진폭발에서는 화염의 확산에 따른 피해예측에도 중요한 자료로 활용될 수 있다. 실험은 마그네슘합금(평균입경 151~161 ${\mu}m$)의 성분비에 따른 폭발특성을 조사하였으며, 밀폐공간의 분진폭발에서 화염전파속도를 계산하기 위하여 분진의 연소시간과 화염면의 도달시간을 고려하고 폭발압력으로부터 추정하는 방법을 사용하였다. 그 결과, Mg-Al(60:40 wt%), Mg-Al(50:50 wt%), Mg-Al(40:60 wt%)의 최대화염전파속도는 각각 15.5, 18, 15.2 m/s가 얻어졌으며 성분비율에 따라 최대화염속도는 변화하는 경향을 나타냈다.

• Journal of Korean Neurosurgical Society
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• 제58권2호
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• pp.101-106
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• 2015

Objective : The aim of this study was to explore the immunity in rats transplanted with adipose-derived mesenchymal stem cells (ADSCs) and acellular nerve (ACN) for repairing sciatic nerve defects. Methods : ADSCs were isolated from the adipose tissues of Wistar rats. Sprague-Dawley rats were used to establish a sciatic nerve defect model and then divided into four groups, according to the following methods : Group A, allogenic nerve graft; Group B, allograft with ACN; Group C, allograft ADSCs+ACN, and Group D, nerve autograft. Results : At the day before transplantation and 3, 7, 14, and 28 days after transplantation, orbital venous blood of the Sprague-Dawley rats in each group was collected to detect the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets using flow cytometry and to determine the serum concentration of interleukin-2 (IL-2), tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) and $interferon-{\gamma}$ ($IFN-{\gamma}$) using enzyme-linked immunosorbent assay (ELISA). At each postoperative time point, the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets and the serum concentration of IL-2, $TNF-{\alpha}$, and $IFN-{\gamma}$ in group C were all near to those in group B and group D, in which no statistically significant difference was observed. As compared with group A, the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets and the serum concentration of IL-2, $TNF-{\alpha}$, and $IFN-{\gamma}$ were significantly reduced in group C (p<0.05). Conclusion : The artificial nerve established with ADSCs and ACN has no obvious allograft rejection for repairing rat nerve defects.

• Korean Chemical Engineering Research
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• 제54권3호
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• pp.367-373
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• 2016

산업분야에서 사용되는 플라스틱 분진은 대부분 가연성이며 화재폭발사고 위험성이 있다. 그러나 산업현장에서 안전한 취급을 위해 활용할 수 있는 폭발특성 자료는 매우 적다. 본 연구에서는 사업장에서 취급하는 다양한 플라스틱 분진 의 폭발특성을 실험적으로 조사하여 관련 자료와 안전정보를 제공하는 것을 목적으로 수행하였다. 이를 위해 20 L 분진폭발시험장치를 사용하여 각종 폭발특성값을 측정하였다. 그 결과 ABS ($209.8{\mu}m$), PE ($81.8{\mu}m$), PBT ($21.3{\mu}m$), MBS ($26.7{\mu}m$) 및 PMMA ($14.3{\mu}m$)시료의 분진폭발지수($K_{st}$)는 각각 62.4, 59.4, 70.3, 303, 203.6[$bar{\cdot}m/s$]의 값이 얻어졌다. 또한 플라스틱 분진폭발에 의한 피해예측을 위하여 분진폭발압력에서 분진의 연소속도가 일정하다고 가정하고 최대압력소요시간 및 화염도달시간을 고려한 화염전파속도모델을 통하여 분진폭발시의 화염전파속도를 추정하였다.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.705-709
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• 2009

본 연구에서는 석송자 분진입자의 거동에 관한 실험적 연구결과를 바탕으로 한 분진화염 전파모델을 제시하였다. 화염전파속도는 분진농도와 함께 증가하여 석송자의 화학양론농도보다 높은 $170g/m^3$에서 최대로 나타났으며 $500g/m^3$까지 완만하게 감소 경향을 나타낸다. 농도 $47{\sim}200g/m^3$에 있어서, 분진입자속도는 화염전파속도에 비례하여 증가한다. 또한, 연소속도와 입자속도의 합이 화염전파속도에 근사한 값을 나타내고 있어, 분진농도에 따른 화염전파속도를 계산에 의해 추정이 가능하였으며, 입자의 거동이 분진의 화염전파속도를 이해하는데 유용하다는 것을 알 수 있었다.