• 한국분말재료학회지
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• 제27권1호
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• pp.37-43
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• 2020

The Fe-22wt.%Cr-6wt.%Al foams were fabricated via the powder alloying process in this study. The structural characteristics, microstructure, and mechanical properties of Fe-Cr-Al foams with different average pore sizes were investigated. Result of the structural analysis shows that the average pore sizes were measured as 474 ㎛ (450 foam) and 1220 ㎛ (1200 foam). Regardless of the pore size, Fe-Cr-Al foams had a Weaire-Phelan bubble structure, and α-ferrite was the major constituent phase. Tensile and compressive tests were conducted with an initial strain rate of 10^-3/s. Tensile yield strengths were 3.4 MPa (450 foam) and 1.4 MPa (1200 foam). Note that the total elongation of 1200 foam was higher than that of 450 foam. Furthermore, their compressive yield strengths were 2.5 MPa (450 foam) and 1.1 MPa (1200 foam), respectively. Different compressive deformation behaviors according to the pore sizes of the Fe-Cr-Al foams were characterized: strain hardening for the 450 foam and constant flow stress after a slight stress drop for the 1200 foam. The effect of structural characteristics on the mechanical properties was also discussed.

• Journal of Astronomy and Space Sciences
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• 제26권4호
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• pp.511-520
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• 2009

이 연구에서는 GPS(Global Positioning System) 정밀단독측위 기법을 이용하여 해양조석하 중(Ocean Tide Loading, OTL) 분조성분을 검출하고, 그 결과를 조석모델에 의한 예측값과 비교하였다. 고정밀 GPS 자료처리 프로그램인 GIPSY를 사용하여 인천, 서산, 제주 GPS 상시관측소를 대상으로 10분 단위의 수직좌표 시계열을 산출하였으며, 시계열의 조석조화분해를 통해 OTL 지각변위를 일으키는 주요 4대 분조($M_2$, $S_2$, $K_1$, $O_1$)의 진폭과 위상을 검출하였다. 조석모델의 예측값을 기준으로 GPS로 산출한 OTL 분조의 정확도를 평가한 결과 진폭은 제주관측소, 위상은 인천관측소에서 가장 높은 정확도를 나타내었다. 주요 11개 분조 중 최대비율을 차지하는 $M_2$분조의 경우 진폭성분에서 평균 23.8%의 상대오차를 보였다.

• 한국콘텐츠학회논문지
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• 제18권5호
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• pp.420-431
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• 2018

본 연구는 가상현실(VR)을 주제로 이용자 관점에서 프레즌스를 기반으로 만족과 지속 이용 의도에 관한 주제로 접근하였다. 설문조사 기관을 통해 의뢰한 569명의 남녀 이용자들이 느끼는 만족과 이를 매개로 한 지속 이용 의도에 대한 연구를 진행하였다. 연구 내용에서는 독립변수인 VR 프레즌스의 구성 요인을 사실감이나 몰입감, 상호작용으로 설정 하였다. 이용자 특성은 개인의 혁신적 성향이나 몰입의 정도, VR 이용 경험으로 설정 하였다. VR 프레즌스와 이용자 특성 그리고 어지러움이나 시각적 피로도로 대표되는 VR 멀미가 콘텐츠 만족과 시스템 만족에 미치는 관계와 지속 이용 의도에 대해 연구 문제와 모델을 제시하였다. 구조방정식(SEM) 모델을 적용한 연구 문제의 해석으로는 8개의 가설이 모두 채택되었다. 결론에서 VR 콘텐츠의 만족을 높이는 요인과 지속적 이용 의도에 가장 큰 영향력으로 작용하는 콘텐츠 만족이 본 연구가 제시하는 핵심 시사점으로 나타났다.

• 한국약용작물학회지
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• 제7권2호
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• pp.115-120
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• 1999

충북, 경남, 전남으로부터 배향초 종자를 수집하여 수원에서 재배하면서 수집종간 정유와 estragol 생산량을 비교한 결과는 다음과 같다. 1. 지상부 건물중을 기준으로 생육정도를 비교한 결과, 가령산종과 순천종은 초기 생육이 좋았으며 목포종과 진도종은 개화 후 생육이 좋았다. 반면 담양종은 수집종 중에서 건물중이 가장 가벼웠다. 2. 대체적으로 estragol 함량은 각각 잎 $82.3{\sim}89.1%$, 화기 $81.1{\sim}89.2%$, 줄기 $72.0{\sim}45.6%$였으며, 수집종간에 큰 차이는 없었고, 개화성기에 가장 높은 함량을 보였다. 3. 정유함량은 개화성기에 1.0% (잎 1.0%, 화기 2.1%, 줄기 0.5%)로 수확시기 중 가장 높았으며, 특히 개화성기에 수확한 목포종의 화기는 3.3%의 정유함량을 보여 가장 많은 함량을 보였다. 4. 건물중과 정유함량이 좋았던 개화성기에 가장 많은 정유와 estragol이 생성되었으며, 수집종중에서는 목포종과 진도종에서 가장 많이 생성되었다.

• 한국응용곤충학회지
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• 제45권1호
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• pp.45-49
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• 2006

꽃노랑총채벌레 성충에 대한 4종 식물정유(muguet flower, patchouli, pennyroyal, spearmint)의 훈증효과를 조사하였다. 그들 중 100%의 훈증효과를 나타낸 정유는 pennyroyal oil과 spearmint oil 이었다. 두 정유에 대한 주요 구성성분을 GC와 GC/MS로 분석한 결과, pennyroyal oil은 pulegone(100.0%), spearmint oil은 ${\beta}-myrcene(3.5%)$, limonene(12.1%), carvone(85.4%)이 주요 구성성분으로 나타났다. 이 성분의 훈증독성 시험결과 carvone과 pulegone은 $1{\mu}{\ell}/45m{\ell}$ air의 약량에서 100%의 높은 훈증독성을 나타내었다.

• International Journal of Human Ecology
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• 제7권1호
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• pp.37-52
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• 2006

This study was designed to analyze the three-dimensional shapes of Hanbok Chima made with various fabrics and to clarify the relationship between fabric properties as well as the objective and subjective evaluations of the 3D shape. For 3D shape data, a dress form (9A2 (N; nude)) was scanned with eight Chima garments made with the same number of fabrics. The scanner used was a non-contact three-dimensional human body measuring system belonging to Bunka Women's University in Japan. Data concerning the objective evaluation of the 3D shape was obtained from the measurements of the vertical and horizontal sections: those for subjective evaluation were through the sensory test after exposure to photographs from a front and side view. Four fabric factors were extracted from fabric physical properties: softness, extension, thickness of threads, and weight of fabric. Such factors as expansion (volume), sag of rear train, shape of nodes were influential in explaining the 3D shape of Hanbok Chima. From the analysis of the 3D shape, it can be deduced that with the constituent fabric stiffer, lighter, and less stretchable, the more expanded the 3D shape appeared to be. Multiple regression results showed that vertical shape factors have a greater effect on the evaluation of the 3D shape. It also implies that dependent variables of this study such as the subjective evaluation and 3D shape can be derived from regression equations on independent variables as fabric property factors or 3D shape factors. These results can enable the manufacturers to predict the 3D shape of the garment as well as the human subjective assessment to improve the efficacy of production. The investigation method proposed in this study can also be applicable to other garment items.

• 한국학교수학회논문집
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• 제13권4호
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• pp.655-678
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• 2010

초등수학에서 기하교육은 공간에 대한 직관의 계발을 통해 도형에 대한 이해와 공간 감각을 이끌어내는데 초점을 맞추어야 한다. 이와 함께 시각화는 기하에서의 문제해결 을 결정짓는 중요한 요소 가운데 하나이다. 지금까지 시각화에 대한 분석은 주로 중등 기하교육에서 다루어진 반면, 초등수학에서 평면도형과 공간도형에서의 문제해결과 관련해서 학생들의 시각화에 대한 논의는 부족했다. 본 연구는 초등수학에서 시각화가 기하문제해결에 미치는 영향을 분석한 것으로, 기하문제해결에서 나타나는 시각화 방법과 시각화에 영향을 미치는 요소, 그리고 이 과정에서 나타나는 어려움을 살펴본 것이다. 먼저 평면도형과 입체도형의 문제해결에서 시각화 방법을 구분하여 살펴보고, 이러한 방법에 따라 도형에 대한 이해와 시각화 과정이 어떻게 진행되는지를 도식화하여 살펴본다. 또한 시각화에 영향을 미치는 요소를 구분하고, 시각화 과정의 어려움으로 인해 어떤 오류가 나타나는가를 살펴보고, 이를 통해 초등기하문제해결에서 시각화에 대한 논의를 이끌어낸다.

• 동의생리병리학회지
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• 제16권6호
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• pp.1277-1283
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• 2002

Silsosangami(SSG) is a formula of treaditional korean medicines as an effective biological response modifier for augmenting host homeostasis of body circulation. Little is known of the biological activity of SSG and previous studies have focused mainly on their anti-thrombosis8). There is a growing interest in the pharmacological potential of the SSG due to the recent finding by our group that SSG and each constituent herbs of SSG were able to inhibit NO and prostaglandin E2 (PGE2) synthesis in murine peritoneal macrophages stimulated with bacterial endotoxin. In this paper, the effects of SSG on platelet aggregation and hemolysis in human blood were studied. SSG provoked remarkable inhibiting effect on platelet aggregation, and APTT were sensitive to the presence of this SSG. Using an in vitro system, APTT was delayed with the increment of the concentrations of these seven compounds. These results suggested that SSG might be used as a novel antithrombotic therapeutic agents in post-myocardial infarction. A SSG reduced NO production in mouse peritoneal macrophages stimulated with lipopolysaccharide, without the influence on the activity of iNOS being observed. SSG significantly reduced mouse paw edema induced by carrageenan. Western blot analysis showed that SSG reduced the expression of iNOS. The results indicate that SSG exerts anti-inflammatory effects related to the inhibition of NO production, which could be due to a decreased expression of iNOS.

• Geomechanics and Engineering
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• 제4권3호
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• pp.173-190
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• 2012

With recent growing interests in the Performance-Based Seismic Design and Assessment Methodology, more realistic modeling of a structural system is deemed essential in analyzing, designing, and evaluating both newly constructed and existing buildings under seismic events. Consequently, a shallow foundation element becomes an essential constituent in the implementation of this seismic design and assessment methodology. In this paper, a contact interface fiber section element is presented for use in modeling soil-shallow foundation systems. The assumption of a rigid footing on a Winkler-based soil rests simply on the Euler-Bernoulli's hypothesis on sectional kinematics. Fiber section discretization is employed to represent the contact interface sectional response. The hyperbolic function provides an adequate means of representing the stress-deformation behavior of each soil fiber. The element is simple but efficient in representing salient features of the soil-shallow foundation system (sliding, settling, and rocking). Two experimental results from centrifuge-scale and full-scale cyclic loading tests on shallow foundations are used to illustrate the model characteristics and verify the accuracy of the model. Based on this comprehensive model validation, it is observed that the model performs quite satisfactorily. It resembles reasonably well the experimental results in terms of moment, shear, settlement, and rotation demands. The hysteretic behavior of moment-rotation responses and the rotation-settlement feature are also captured well by the model.

• Journal of the Korean Wood Science and Technology
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• 제42권5호
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• pp.533-542
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• 2014

We extracted essential oils from four species (Pinus densiflora, Larix kaempferi, Pinus koraiensis, and Abies holophylla) in the family Pinaceae to investigate their antibacterial activities against respiratory tract bacteria (Klebsiella pneumoniae, Haemophillus influenzae, Streptococcus pyogenes, Streptococcus pneumonia, and Neisseria meningitides). Among the tested oils, that from A. holophylla was showed strong activity based on disc diffusion and broth medium dilution (minimum inhibitory concentration, MIC) assays. Qualitative analysis of A. holophylla oil was carried out by GC-MS; ${\alpha}$-pinene, camphene, ${\beta}$-pinene, 3-carene, limonene, bornyl acetate, borneol, ${\beta}$-caryophyllene, ${\alpha}$-caryophyllene, caryophyllene oxide, and ${\alpha}$-bisabolol were identified as its major constituents. Fractionation by silica gel chromatography was performed to analyze the active constituents of the crude oil. In particular, one fraction containing caryophyllene oxide as the major constituent showed stronger antibacterial activity than the crude oil of A. holophylla. Growth rates of bacterial strains exposed to fraction D were explored by optical density (OD600) measurements while morphology was examined by optical microscopy observations ( ${\times}1000$). OD600 of K. pneumoniae decreased from 0.2582 to 0.005 in response to treatment with fraction D at a MIC value of $0.31{\mu}{\ell}/m{\ell}$.