• 한국자동차공학회논문집
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• 제14권3호
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• pp.164-169
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• 2006

A systematic methodology has been proposed to establish a reliable design of water pump system. A simplified steady-state dynamic model of water pump system has been developed to study the response of water pump system to the dynamic load mainly due to the run-out and unbalance. Design modifications are needed to strengthen the structural integrity of existing designs. Increasing the natural frequency of system is pursued to prevent a resonance from occurring in the engine excitation range. A computational reliability methodology combined with finite element analysis is used to identify the most significant factor affecting the system performance. This method considered influence of design control parameters for the performance of design. By including control factors to the system model in a systematic way, more reliable design is expected.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.339-342
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• 2005

This paper presents the development of a method for determining the response modification factor, using traffic load. The proposed method is based on the results of computer simulations of traffic action effects. The simulation program generates random traffic actions for defined traffic conditions and determines the frequency distribution of maximum traffic action effects. Therefore, this study is adopted to long-span bridge for the verification of the proposed method. A comparison between the proposed method and present method shows good agreement in estimating the modified load carrying capacity of bridges.

• Structural Engineering and Mechanics
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• 제17권1호
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• pp.69-85
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• 2004

The novel form of composite walling system consists of two skins of profiled steel sheeting with an in-fill of concrete. Such walling system can be used as shear elements in steel framed building subjected to lateral load. This paper presents the results of small-scale model tests on composite wall and its components manufactured from very thin sheeting and micro-concrete tested under monotonic and cyclic shear loading conditions. The heavily instrumented small-scale tests provided information on the load-deformation response, strength, stiffness, strain condition, sheet-concrete interaction and failure modes. Analytical models for shear strength and stiffness are derived with some modification factor to take into account the effect of quasi-static cycling loading. The performance of design equations is validated through experimental results.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.377-384
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• 2003

Recently, there are much concerns about new and innovative transverse materials which could be used instead of conventional transverse steel in reinforced concrete bridge piers. FRP materials could be substituted for conventional transverse steel because of their sufficient strength, light weight, easy fabrication, and useful applicability to any shapes of pier sections, such as rectangular or circular sections. The objective of this research is to evaluate the seismic performance of reinforced concrete bridge pier specimens with FRP transverse reinforcement by means of the Quasi-Static test. In the first task, test columns were made using FRP rope, but these specimens appeared to fail at low displacement ductility levels due to insufficient confinement of strand extension itself. Therefore, the second task was to evaluate the seismic performance of test specimens transversely confined with FRP band. Although FRP banded specimens showed lower seismic performance than the specimen with spiral reinforcing steel, it satisfied with the response modification factor, 3, required for the single column of Korea bridge roadway design code. It was concluded that FRP band could be efficiently substituted for conventional reinforcing steel.

• 대한토목학회논문집
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• 제35권1호
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• pp.31-38
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• 2015

본 논문에서는 한국시설안전공단에서 수행한 정밀안전진단자료를 수집 분석하여 공용년수의 증가에 따른 내하력 변화 양상을 조사하였다. 연구결과, 공용내하율이 평가자의 주관 등 여러 가지 조건으로 공용기간에 따라 큰 편차를 보이는 것을 알 수 있었다. 따라서, 기존의 내하력 평가에 관한 다양한 문제점을 분석하여 편차를 보정할 수 있는 개선된 방안을 제시하였으며, 이 방법은 공용중인 교량의 보강 주기와 우선순위의 결정, 공용수명의 추정 등 효율적인 유지관리에 활용될 수 있을 것으로 기대된다.

• 한국강구조학회 논문집
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• 제23권2호
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• pp.189-198
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• 2011

최근 건축물들이 미적인 아름다움을 추구하며 점차 비정형화 되어감에 따라 이를 실현시켜 주기 위한 새로운 구조시스템들이 개발되고 있다. Diagrid system은 외각에 배치 된 경사진 기둥을 통해 구조물의 중력하중과 횡력을 모두 저항하는 시스템으로 건물 내부에 기둥이 없어 비교적 평면 변화에 유리한 시스템이다. 하지만 현행의 내진설계 기준에는 이와 같은 새로운 구조시스템에 대한 내진성능계수가 명시되어 있지 않다. 이에 새로운 내진성능 평가 방법인 ATC-63이 제안되었다. 본 논문에서는 구조물의 비정형성을 고려해주기 위해 3D 비선형 해석 모델에 각각 작용하는 하중의 방향을 달리하며 ATC-63에서 제시하고 있는 절차에 따라 비정형 Diagrid system의 내진성능을 평가하였다.

• 한국초지조사료학회지
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• 제41권4호
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• pp.242-249
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• 2021

Forage crop management is severely challenged by global warming-induced climate changes representing diverse a/biotic stresses. Thus, screening of valuable genetic resources would be applied to develop stress-tolerant forage crops. We isolated two NAC (NAM, ATAF1, ATAF2, CUC2) transcription factors (ANAC032 and ANAC083) transcriptionally activated by multi-abiotic stresses (salt, drought, and cold stresses) from Arabidopsis by microarray analysis. The NAC family is one of the most prominent transcription factor families in plants and functions in various biological processes. The enhanced expressions of two ANACs by multi-abiotic stresses were validated by quantitative RT-PCR analysis. We also confirmed that both ANACs were localized in the nucleus, suggesting that ANAC032 and ANAC083 act as transcription factors to regulate the expression of downstream target genes. Promoter activities of ANAC032 and ANAC083 through histochemical GUS staining again suggested that various abiotic stresses strongly drive both ANACs expressions. Our data suggest that ANAC032 and ANAC083 would be valuable genetic candidates for breeding multi-abiotic stress-tolerant forage crops via the genetic modification of a single gene.

• 미생물학회지
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• 제49권3호
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• pp.215-220
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• 2013

많은 세균들은 환경적 스트레스에 대항하기 위해 세균 생존에 유용한 특정 유전자들의 전사를 유도하는 대체시그마 인자 RpoS를 활용한다. 세포 내 RpoS 단백질의 농도는 주로 ClpXP 단백질 분해효소의 조절을 통해 결정된다. RpoS를 ClpXP로 전달하기 위해서는 adaptor 단백질 RssB가 반드시 필요하다. Two-component-type response regulator RssB는 RpoS와 지속적으로 상호작용을 하지만, 다양한 환경변화에 의해 RssB-RpoS 상호작용이 억제되어 세균에서 RpoS 양을 증가시킨다. 본 총설에서는 최근까지 연구 된 RssB-RpoS 상호작용에 관여하는 RssB의 anti-adaptor 단백질 IraD, IraM, IraP 등의 조절인자들과 RssB의 N-terminal 수용체 도메인의 인산화에 대해 설명하고 요약하였다. 이러한 RssB의 정교한 활성을 통한 RpoS 분해조절 과정은 외부환경 스트레스로부터 보다 효율적으로 세균을 보호할 수 있다.

• 한국구조물진단유지관리공학회 논문집
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• 제25권6호
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• pp.235-244
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• 2021

본 연구에서는 한계상태설계법에 기반한 교량 평가법을 개발하기 위하여, 공용 중인 교량의 실측실험을 반영하여 적용성을 분석하였다. 예제 PSC Beam 실 교량의 부재 실험 결과로부터 부재의 시험강도를 구하였으며, 재료 시험값으로부터 추정된 통계특성을 적용하여 산정된 저항강도와 시험강도를 비교하였다. 부재의 시험강도와 재료의 변동성을 고려한 저항강도는 동등한 수준으로 계산되어 실측실험의 적합성이 검증되었다. 차량재하시험으로부터 응답보정계수와 동적충격계수를 계산하였으며, 실측실험 결과를 반영한 내하율을 적용하여 현행 교량 평가법과 한계상태설계법 기반으로 산정된 내하율을 비교하였다. 재료 시험값의 통계특성으로부터 추정된 부재 저항강도의 통계특성을 적용하여 실 교량의 신뢰도지수를 계산하였다. 설계기준 개발에 적용한 저항강도 통계특성으로 구한 신뢰도지수보다 실측실험의 통계특성을 적용하는 경우 더 큰 값의 신뢰도지수를 얻었다.

• The Korean Journal of Physiology and Pharmacology
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• 제18권3호
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• pp.191-200
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• 2014

We investigated the anxiolytic-like activity of ${\alpha}$-asarone (AAS) from Acorus gramineus in an experimental rat model of anxiety induced by repeated administration of the exogenous stress hormone corticosterone (CORT). The putative anxiolytic effect of AAS was studied in behavioral tests of anxiety, such as the elevated plus maze (EPM) test and the hole-board test (HBT) in rats. For 21 consecutive days, male rats received 50, 100, or 200 mg/kg AAS (i.p.) 30 min prior to a daily injection of CORT. Dysregulation of the HPA axis in response to the repeated CORT injections was confirmed by measuring serum levels of CORT and the expression of corticotrophin-releasing factor (CRF) in the hypothalamus. Daily AAS (200 mg/kg) administration increased open-arm exploration significantly in the EPM test, and it increased the duration of head dipping activity in the HBT. It also blocked the increase in tyrosine hydroxylase (TH) expression in the locus coeruleus (LC) and decreased mRNA expression of brain-derived neurotrophic factor (BDNF) and its receptor, TrkB, in the hippocampus. These results indicated that the administration of AAS prior to high-dose exogenous CORT significantly improved anxiety-like behaviors, which are associated with modification of the central noradrenergic system and with BDNF function in rats. The current finding may improve understanding of the neurobiological mechanisms responsible for changes in emotions induced by repeated administration of high doses of CORT or by elevated levels of hormones associated with chronic stress. Thus, AAS did exhibit an anxiolytic-like effects in animal models of anxiety.