• Tribology and Lubricants
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• 제25권3호
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• pp.176-181
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• 2009

Aminated polyacrylonitrile as the new organic disperse phases of the anhydrous ER fluid has been synthesized and ER effect of the suspension composed of aminated polyacrylonitrile in silicone oil investigated. The suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.6 power on theelectric field. The current density and the conductivity of the of aminated polyacrylonitrile suspension increase with the electric field intensity and moreover the conductivity of the suspension is about 8 order of magnitude higher than that of the silicone oil. On the basis of the the results, aminated polyacrylonitrile suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amine polar group of the aminated polyacrylonitrile particles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.394-399
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• 1997

This paper presents a new concept of a semi-active suspension system for a commercial vehicle seat. The proposed suspension system features an ER(electro-rheological) damper which can produce continuously tunable damping forces by control electric fields. A dynamic model of the ER damper is first achieved by incorporating Bingham property of the ER fluid, followed by the formulation of governing equations of motion for the suspension system. A sliding mode controller is then designed on the basis of the hyper-plane sliding mode scheme. The effectiveness of the proposed control system is evaluated by investigating control performance for vibration isolation.

• Nuclear Engineering and Technology
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• 제28권2호
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• pp.118-128
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• 1996

0$\leq$y$\leq$0.33 범위의 조성을 가진 $U_{1-y}Er_{y}O_{2{\pm}x}$ 고용체의 격자상수를 least-squares method에 의해 구하였다. 고용체의 격자상수는 Er의 첨가량이 증가함에 따라 다음과 같이 직선적으로 감소하였다 : a($\AA$)=5.4695-0.220y, (0$\leq$y$\leq$0.33). $U_{1-y}Er_{y}O_2$고용체에서 Er 함량에 대한 격자상수의 변화계수, y=-0.220은 $Er^{3+}$ 의 첨가에 따른 전기적 중성을 만족하기 위해 고용체내에서 $U^{5+}$ 또는 $U^{6+}$ 이온이 각각 존재한다고 가정하여 계산된 값, y =-0.273, -0.156의 사이에 있다. $U_{1-y}Er_{y}O_2$ 고용체와 $UO_{2+x}$ 의 산소포텐샬을 산소분압 $10^{-14}$ -$10^{-3}$, 온도 1200~$1500^{\circ}C$에서 thermogravimetric method에 의해 측정하였다. $CO_2$/CO 혼합가스로써 TGA내의 산소분압을 조절하였으며, 고온산소센서를 사용하여 $Po_2$ 값을 측정하였다. (equation omitted) 값은 1200~$1500^{\circ}C$ 범위에서 y=0.06인 고용체의 경우 -360부터 -270H1mo1e, 그리고 y=0.20인 고용체에서는 -320부터 -220kJ/mo1e까지 각각 급격하게 변하는 것으로 나타났다. $U_{1-y}Er_{y}O_{2{\pm}x}$ 고용체에서 Er의 함량이 낮은 경우에는 $U^{5+}$ $U^{4+}$ model이 산소포텐샬 데이타에 접근하는 것으로 나타났으나, y=0.06 이 상인 경우에는 평균 우라늄 원자가모델에 의해서 산소 포텐샬의 변화를 설명할 수 없었다.

• KSTLE International Journal
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• 제2권2호
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• pp.142-145
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• 2001

The electrorheology of the chitosan adipnate suspension in silicone oil was investigated. Chitosan adipnate suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the chitosan adipnate suspension exhibited a linear dependence on the volume fraction of particles and an electric field power of 1.88. The experimental results for the chitosan adipnate suspension correlated with the conduction models and this suspension was found to be an anhydrous ER fluid.

• KSTLE International Journal
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• 제4권1호
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• pp.14-17
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• 2003

The electrical and rheological properties of a chitosan malonate suspension in silicone oil was investigated by varying the electric fields, volume fractions of particles, and shear rates, respectively, The chitosan malonate susepnsion showed a typical electrorheological (ER) response caused by the polarizability of an amide polar group and shear yield stress due to the formation of multiple chains upon application of an electric field. The shear stress fur the suspension exhibited a linear dependence on the volume fraction and an electric field power of 1.88. On the basis of the experimental results, the newly synthesized chitosan malonate suspension was found to be an anhydrous ER fluid.

• 정보관리학회지
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• 제22권3호
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• pp.289-306
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• 2005

FRBR 모델에서는 서지 요소와 관계를 중심으로 ER 모델링 방식을 제공하고 있지만, 단지 구조적 프레임워크로서 FRBR 모델을 효율적으로 구현할 수 있는 도구가 필요하다. 본 연구에서는 Topic Maps를 이용하여 FRBR 모델을 구현하는 방법을 제시한다. Topic Maps 기반의 FRBR 모델 구현의 유효성을 실증적으로 보이기 위하여, 명성황후라는 주제와 관련된 MARC 데이터를 추출하여 FRBR 모델을 설계하였고, Topic Maps를 이용하여 이를 구현하였다. 연구 결과, FRBR의 entity-relation과 Topic Maps의 topic-association이 개념적으로 동일하기 때문에 FRBR 모델 개발의 적합함을 알 수 있었다. FRBR 구조는 Topic Maps 패러다임과 그대로 일치하기 때문에 FRBR 모델은 Topic Maps로 구현함이 바람직하다.

• 한국콘텐츠학회논문지
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• 제20권3호
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• pp.462-469
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• 2020

본 연구는 고등학교 영어교육에서의 영어 다독 지도 방안을 연구하기 위해, D 광역시에 소재한 두 개의 인문계 고등학교를 방문하여, 본 연구자가 영어 다독에 대한 소개와 수준별 읽기 도서를 고등학생들에게 직접 체험하게 한 후, 영어 다독에 대한 고등학생들의 인식을 조사하였다. 또한, 중학교뿐 아니라, 고등학교에서도 자유학기제가 확대됨에 따라 영어교사들의 영어 다독 수업에 대한 요구가 증가하였다. 이러한 배경을 토대로 자유학기제에 활용 가능한 영어 다독 수업 모형을 개발하고자 했다. 본 연구에 참여한 고등학생 35명은 영어 다독에 대한 안내 및 체험 후, 다독 중심의 영어 독해 공부를 시도해 보고 싶은 생각이 있다고 밝혔다(91.4%). 도움이 된 다독 체험 요소로는 '다섯 손가락 원칙'과 '수준별 도서 목록'을 들었다. 영어교사들과 이루어진 인터뷰에서 교사들은 자유학기제에 활용 가능한 영어 다독 수업 모형에 대한 개발 요구를 피력했다. 본 연구는 고등학교에서 실제 이뤄지고 있는 수행평가 중심의 영어 다독 수업과 더불어 자유학기제에 활용 가능한 도서관 활용 다독 수업 모형을 제안하고자 한다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(3)
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• pp.231-237
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• 1996

Defect equilibrium equations were modelled, and the relations of P $o_2$, venus x were derived using the mass action law. The dominant defect species active in a specified region were determined by fitting the curve of experimental data to the calculated curve of log P $o_2$, versus log x for each theoretical model. The calculated curve for (2:1:2) and (Er')$^{x}$ in the hyperstoichiometric $U_{1-y}$E $r_{y}$ $O_{2＋x}$ and that for (2Er'quot;)$^{x}$ $_{dec}$ in the hypostoichiometric $U_{1-y}$E $r_{y}$ $O_{2－x}$ are in good agreement with the present experimental results. The sintering behavior of Er-doped U $O_2$ is observed with erbium content in oxidizing and reducing atmospheres. For sintering in oxidizing atmosphere, sintered density decreases as increasing y in $U_{1-y}$E $r_{y}$ $O_{2＋x}$. However, in hydrogen atmosphere, sintered density decreases as increasing y at lower erbium content but the density increases again above y=0.10. In oxidizing sintering conditions, the formation of (Er'U')$^{x}$ clusters hinders the diffusion of cations, and hence the sinterability of Er-doped U $O_2$ decreases. In reducing atmosphere of Er-doped U $O_2$ for higher Er concent, the oxygen vacancies make (Er')$^{x}$ cluster decompose by charge compensation and the concentration of mobile cations increases, thereby improving the sinterability.ntration of mobile cations increases, thereby improving the sinterability.ability.

• 대한본초학회지
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• 제29권4호
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• pp.35-44
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• 2014

Objectives : Evodia rutaecarpa (Juss.) Benth.(ER) and Chaenomeles sinensis Koehne (CS) have multiple applications and were known to have anti-inflammatory effects. In the current study, we investigated to clearly understand the mechanism of therapeutic role for CS, ER and their combination in CIA model mice. Methods : DBA/1OlaHsd mice were immunized with bovine type II collagen. After a second collagen immunization, mice were treated with CS, ER and their combination once a day for 7 weeks. Cytokine production and gene expression were assessed during CIA (collagen-induced arthritis) model mice in knee joint, lymph node (LN) using ELISA and FACS analysis. The severity of arthritis within the knee joints was evaluated by histological assessment of cartilage destruction and pannus formation. Result : Oral administration of CS, ER and their combination (150 mg/kg) significantly suppressed the progression of CIA, and significantly suppressed the progression of CIA and inhibited the production of TNF-${\alpha}$ and IL-6 in serum. The erosion of cartilage was dramatically reduced in mouse knees after treatment with CS plus ER. Conclusion : These result suggest that CS plus ER significantly suppressed the progression of CIA and that this action was characterized by the decreased production of TNF-${\alpha}$, IL-6 and collagen II specific antibody in serum.

• 한국소음진동공학회논문집
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• 제11권4호
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• pp.13-21
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• 2001

Electrorheological(ER) fluid is a kind of smart material with variable shear stress and dynamic viscosity under various electric field intensity. Electric field can control the damping characteristics of ER damper. The objective of this study is the analysis of the performance of ER damper and its application to shock absorber. Idealized nonlinear Bingham plastic shear flow model is used to predict the velocity profile between electrodes. Cylindrical dashpot ER damper with moving electrode is constructed and tested under various electric fields. The analytic and experimental results for damping force are compared and discussed. Drop test system using ER damper is prepared to identify transient vibration characteristics. The rebound is eased as the applied electric field increases. When semi-active control algorithm is applied, rebound phenomenon disappears and vibration energy level decays faster than the case of zero electric field.