• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.42-51
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• 1998

안전한고 쾌적한 보행환경을 조성하여 보행 교통을 활성화시킨다면, 자동차의 사용이 줄게 되고 자동차의 유해한 배출가스로 인한 공기 오염 및 소음 등을 낮출 수 있을 뿐만 아니라 도심부의 미관 증대, 역사적 구역의 보존, 물리적인 도시 이미지 향상 등의 효과로 도심기능의 활성화에 기여할 수 있을 것이다. 이와 같은 보행통행의 중요성을 인식하여 안전하고 효율성 있는 보행동선을 조성할 필요가 있다. 그러나 상당수의 종합병원과 같은 공공성을 띤 건물들은 대부분의 보행자가 보행동선을 이용하여 건물에 접근하는데도 불구하고 차량을 중심으로 동선이 운영되고 있는 실정이다. 차량위주의 동선 체계는 보행 통행자로 하여금 차량통행으로의 전환을 유도할 가능성이 있어 이에 대한 대책이 필요하다. 본 연구는 분석대상으로 차량과 보행자에게 동등하게 접근의 용이성을 제공해야 하는 광주시의 4대 종합병원을 대상으로 보행자 집단에게 가해지는 저항이 구체적으로 얼마나 심각하며, 그 원인은 어떠한 물리적 조건에 의하여 발생하는지 알아 보았다. 보행저항을 파악하기 위한 지표로는 차량과 보행자의 충돌점의 수, 최단거리 선호도, 보행로 미확보율 등을 설정하여 분석하였다. 이러한 분석의 결과 나타난 문제점들을 해결하기 위한 방안도 함께 모색하였다.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.279-287
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• 2013

The steel members are applied to high rise building since they have high strength compare to the concrete member. On the other hand, the elastic buckling is likely to occur in steel member because of their small section. When the elastic buckling occur, the steel structure lose a load carrying capacity. The steel frame would be unstable due to a rapid decline in strength by buckling. The purpose of this study is the development of FLD(Force Limiting Device) to prevent a elastic buckling for a slender member. Further, the behavior of steel structures with FLD would be stable by high energy absorption capacity. The proposed type of FLD is the type of out-of-plane resistance. In this study, member test and FEM analysis for proposed type were performed. The test parameters are thickness and gradient angle of out-of-plane plate. The proposed type may be effective method for FLD.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.129-134
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• 2005

Effective micropropagation system via somatic embryognesis was established for a Phytophthora resistant Aralia elata cultivar. Different kinds of growth regulators were needed to induce embryogenic callus with different explant sources. When leaf explants were used, a combination of 2,4-D, TDZ and L-glutamine was needed, whereas when petiole and root explants needed only 1.0 mg/L 2,4-D. Embryogenic callus induction rate under the optimum culture condition was 75.0%, 67.0% and 83.0% from leaf, petiole and root segment, respectively. Somatic embryo germination and plantlet conversion rate appeared to be influenced greatly by various osmoticums. More than 90% of embryos germinated when treated with sucrose, glucose and maltose. However, the highest conversion rate (72%) was recorded on medium with 2% sucrose only. The converted plantlets grew normally on 1/2MS basal medium, were acclimatized on artificial soil mixture and survived more than 95% in the greenhouse condition. The results suggest that the species can be clonally propagated through in vitro culture system via somatic embryogenesis.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.210-219
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• 2000

The magnetoresistance characteristics of FeN/Co/Cu/Co and FeN/Co/Cu/Co/Cu/Co/FeN multilayers using ferromagnetic iron-nitrides (FeN) has been studied. The microstructure of FeN film is the mixed ${\alpha}$-Fe and $\varepsilon$-Fe$_3$N phase on the condition that the flow rate of N$_2$ gas is over 0.4 sccm. The magnetoresistance effect is observed because of shape magnetic anisotropy induced by needle-shaped $\varepsilon$-Fe$_3$N phase. This magnetoresistance effect changes, because the degree that the shape magnetic anisotropy adheres to the adjacent Co pinned layer is varied according to the flow rate of N$_2$ gas and the thickness of FeN film. The best magnetoresistance effect is obtained on the condition that the thickness of Co free layer is 70 ${\AA}$ and the maximum MR ratio(%) value of 3.2% shows in the FeN(250 ${\AA}$)/Co(70 ${\AA}$)/Cu(25 ${\AA}$)/Co(70 ${\AA}$)/Cu(25 ${\AA}$)/Co(70 ${\AA}$)/FeN(250 ${\AA}$) mutilayer film which is fabricated at the N, gas flow rate of 0.5 sccm and the FeN film thickness of 250 ${\AA}$. Four steps are observed in the magnetoresistance curve owing to this difference of coercive force, because respective magnetic layers in the multilayer possess different coercive forces. These effects observed in these mutilayer films can be expected to application to the memory device the same MRAM as can carry out simultaneously four signals.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.59-65
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• 2014

Two input resistances converted from $S_{11}$-parameter and $Z_{11}$-parameter of MOSFETs with various gate finger numbers Nf were measured in low frequency region. The 1/Nf dependent input resistance from $S_{11}$-parameter exhibits much lower values than that from $Z_{11}$-parameter in the range of $Nf{\leq}64$. This 1/Nf dependence was theoretically verified by using Nf dependent nonlinear equation derived from a MOSFET equivalent circuit.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.189-192
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• 2001

We have investigated the effects of abiotic and biotic stresses on leaf senescence using transgenic tobacco plants, in which cellular contents of polyamines were increased by introducing the genes of polyamine and ethylene biosynthesis in sense or antisense orientation. These transgenic plants showed accumulations of polyamines at higher levels than were found in wild-type. Stress-induced senescence was attenuated in transgenic plants cpmpared with wild-type plants, in terms of total chlorphyll loss and phenotypic changes after oxidative stress of hydrogen peroxide($H_2O_2$), high salinity, acid stress (pH3.0), ABA and fungal pathogen(phytophothora parasitica pv.Nicotianae). Transcripts for antioxidant enzyme, glutathionine-S-transferase and catalase, were also more abundant in transgenic plants than wild-type plants. These result suggested that higher expression of those genes caused a broad-spectrum resistance to abiotic stress/biotic stress. These phenomena indicate that polyamines may play an important role in contributing to the antioxidant defense function in plants. Our findings suggest that facilitate the improvement of stress tolerance of crop plants.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.321-326
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• 2001

Contribution of Wolbachia infection to fitness of a species (developmental time, adult life span, fecundity and ovipositional period) was measured in the susceptible and dicofol-resistant strains of two spotted spider mite, Tetranychus urticae Koch, on miniature roses. Based on ftsZPCR assay, Wolbachia infection was confirmed only in the susceptible strain. The susceptible strain had significantly higher fecundity (eggs/female) and shorter developmental times than the resistant strain. Longer adult life span and ovipositional period were observed in the susceptible strain. Fitness differences were appeared to influence dicofol resistance development. Similar measurements were performed with progeny from two reciprocal $F_1$crosses. Similar to other examples of cytoplasmic incompatibility induced by Wolbachia, subsequent cross between uninfected female and infected male spider mites were different from the other combination: a high egg mortality and a male-biased sex ratio. When the intrinsic rate of natural increase was calculated, the cross between uninfected female and infected male spider mites had a significantly lower rate($0.09\pm$0.01) than did the other combination ($0.20\pm$0.01). These results suggest that the dynamic and evolution of the fitness are closely associated with dicofol resistance and Wolbachia infection in the two spotted spider mites.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.87-97
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• 1990

There is the need to balance safety, economy and serviceability in all phases of society problems. This is especially true in structural code formulation. where a framework is established by which practicing structural engineers can be assured of designing structures that reasonably meet the above three objectives. The existing design codes, which are generally based on the structural theory and certain engineering experience, do not realistically consider the uncertainties of loads and resistances and the basic reliability concepts. The purpose of the present study is therefore to develop the realistic reliability-based design criteria to secure adequate safety arid reliability, and to derive the models for partial and combined resistance factor formats. To this end, the reliability levels of our existing design code for concrete structures are first evaluated and the target reliabilities are determined, the new code formats are evolved from these target reliabilities. The present study indicates that the proposed formats exhibit relatively-uniform reliability and reasonably take into account the different material characteristics of concrete and steel in concrete structures.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.171-172
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• 2013

종래의 흑연 위주 연료전지 분리판 개발되어 최근 고분자 전해질 막 연료전지가 높은 전력, 낮은 배기 가스 배출, 낮은 작동 온도로 자동차 산업에서 상당한 주목을 받고 있다. 요구사항은 높은 전기 전도도, 높은 내식성, 낮은 가스 투과성, 낮은 무게, 쉬운 가공, 낮은 제조비용이다. Thin film Cr 장비로 저항가열 furnace, sputter 등이 사용된다. 연료전지 분리판의 고전도도, 내부식성 보호막의 고속 증착을 위한 새로운 증착원으로 스퍼터 - 승화형 소스의 가능성을 유도 결합 플라즈마에 금속 봉을 직류 바이어스 함으로써 시도하였다. 유도 결합 플라즈마를 이용하여 승화증착 시스템을 사용하여 OES(SQ-2000)와 QMS (CPM-300)를 사용하여 $N_2$ flow에 따른 유도 결합 플라즈마를 이용한 스퍼터-승화 증착 시스템을 사용하여도 균일한 공정을 하는 것을 확인 하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2107-2108
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• 2011

전력계통의 절연설계에 있어 뇌과전압을 정확하게 측정하고 분석하는 것은 매우 중요하다 할 수 있다. 유도뢰 해석의 일환인 수치해석은 계산식을 기반으로 유도뢰 차폐효과에 대해 해석이 가능하나 이러한 수치적 해석은 선로정수, 뇌격전류의 크기 또는 접지저항 값이 변경되었을 경우 재계산을 하는데 다소 복잡한 과정을 거쳐야하기 때문에 이를 일괄적으로 처리할 수 있는 프로그램의 개발 필요성이 대두되었다. 이에 유도뢰 차폐효과 계산 프로그램을 MATLAB을 사용하여 개발하였다.