• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.228-234
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• 1991

- A synthetic gene coding for human interleukin-2 (IL-2) was constructed from the oligonucleotides synthesized by an automatic DNA synthesizer. The nucleotide sequence of the synthetic gene was chosen considering the preferred codons of E. coEi by not changing the amino acid sequence of IL-2 polypeptide. The synthetic gene was expressed in E. coli by placing the gene under the control of the $\lambda$ PL promoter. IL-2 was produced in the E. coli cytoplasm in the form of inclusion bodies. The recombinant IL-2 showed growth promoting activity on the IL-2 dependent cell line.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.102-111
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• 1993

One of the most important design procedures for large sized structures is the evaluation of fracture strength against fatigue and brittle fractures threatening to occur in their steel members. In this paper, the safety assessment based upon the knowledge about the fracturing characteristics of such ship structures was discussed, which can be estimated from such phenomena as fatigue crack propagation and brittle fractures, as obtained by employing fracture mechanics at the basic design stage. Model tests with a partial structure specimen of full size was carried out to authenticate a question as to whether or not the fracturing characteristics of such sophisticated structures could be estimated with precision from ordinary scale specimen tests, It was shown that the behviour of fatigue crack growth of large sized structures in this study could be predicted from the results of ordinary scale specimen test.

• Journal of the Korean Ceramic Society
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• v.17 no.2
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• pp.69-74
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• 1980

This study deals with the wire content, wire diameter, aspect ratio , it's arrangement of steel, wire fiber and the sorts of castable which affected the character of steel wire fiber reinformced refractory castable. Two kinds of alumina based refractory castables, one is for 1650℃ and the other is for 1800℃, and stainless steel which is SUS 304 type 0.25, 0.34 , 0.37 and 0.50m/min diameter were used respectively. Aspect ratio was adjusted to 50, 75, 100 and steel fiber content was also adjusted to 1-4wt% each. The results of the experiment were as follows : 1. At firing temperature around 1,000℃, MOR is increased with increasing wire content and aspect ratio with decreasing firing temperature, which depends on the Romualdi's Fiber Spacing Theory. But for calculation of the fiber spacing, Swamy equation is more a aplicable to the extensive fiber mixing conditions. However, the condition differs from the above at firing temperature around 1,350℃ ,because of the degradation of wire and the progress of sintering of castable. 2. Linear change is getting larger corresponding to the increase of wire content, and the spaling resistivity is increasing corresponding to the increase of wire content and to aspect ratio, and with decreasing wire diameter. 3. Firing shrinkage under load is getting greater as higher wire content, and the shrinkage of the test pieces which fiber is vertically oriented is getting greater than the test pieces which fiber is randomly oriented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.483-484
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• 2008

AC-PDP는 구조적으로 2장의 유리, 유전체, 전극으로 구성된다. AC-PDP의 전기적특성은 유전체의 물성에 크게 좌우된다. AC-PDP의 유전체는 주변 온도와 주파수에 따라 유전율 및 유전손실 특성이 달라지므로 온도와 주파수에 따른 유전물질의 물성변화와 panel의 전기적특성에 대한 연구가 필요하다. 본 논문에서는 온도와 주파수에 따른 AC-PDP내 유전체의 유전율 및 유전손실에 대한 특성에 대해 알아보고 4인치 test 패널을 제작하여 온도와 주파수에 따른 panel의 전기적특성 관계를 살펴보았다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.567-572
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• 2015

Discharge characteristics of linear microwave plasma were investigated by using fluid simulation of 2D axis-symmetry based on finite elements method. The microwave power was 2.45 GHz TEM mode and transmitted through linear antenna. Resistive power and pressure were considered simulation variables and argon was used for working gas. A decrease of electron density along the quartz tube was observed in low power condition but relatively uniform plasmas were generated in chamber by increasing the resistive power. The electron temperature was highly detected near the surface of quartz tube because the electron was heated only dielectric surface. The power transmission efficiency decreased and characteristics of surface plasma were observed in high electron density condition.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.908-910
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• 1998

Modern AC electric car has PWM(Pulse Width Modulation) -controlled converters, which give rise to higher harmonics. The current harmonics injected from AC electric car is propagated through power feeding circuit. As the feeding circuit is a distributed constant circuit composed of RLC, the capacitance of the feeding circuit and the inductance on the side of power system cause a parallel resonance and a magnification of current harmonics at a specific frequency. The magnified current harmonics usually brings about various problems. That is, the current harmonics makes interference in the adjacent lines of communications and the railway signalling system. Furthermore, in case it flows on the side of power system, not only overheating and vibration at the power capacitors but also wrong operation at the protective devices can occur. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. From these point of view, this study presents an approach to model and to analyse traction power feeding system focused on the amplification of harmonic current. The proposed algorithm is applied to a standard AT(Auto-transformer)-fed test system in which electric car with PWM-controlled converters is running.

• Journal of the Korean Institute of Educational Facilities
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• v.3 no.3
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• pp.41-57
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• 1996

본 연구는 광희중학교 학구내에서 재개발로 인하여 증가되는 인구수을 예측하여 장래 중학교 학생수를 예측하였다. 2016까지 학급당 학생수를 37명으로 하고 36학급 규모의 학교를 추구한다면 중학교는 적어도 1개 더 건축하여야만 재개발로 늘어나는 제1학군의 학생수를 수용할 수있을 것음을 분석하였다. 또, 교과과정을 분석한 결과 도덕 2.5교실, 국어 6교실, 사회 5교실, 수학 5교실, 과학 5교실, 체육 4교실, 음악 2교실, 미술 2교실, 가정 1.5교실, 기술 3교실, 영어 5.5교실, 한문 1교실, 컴퓨터 1교실로 분석되어 이용율이 88%가 되었다. 본 연구는 광희중학교 구체적 건축계획에 앞서 계획의 모델을 설정하여 이를 토대로 계획에 임하였다. 광희중학교 주변의 접근성, 교통 조건, 소음 상태, 지역사회인의 이용, 전망 등의 환경 분석을 토대로 4개의 죠닝(Zonning)안을 제시하여 평가한 후 가장 바람직한 안을 선정하였다. 이를 토대로 브록(Block)프랜을 5개 작성하여 평가후 1개 안을 채택하여 구체적 평면 계획안을 작성하였다. 36학급 37명 학생수를 기준으로 교과교실형으로 계획하였으며 특별 교실형의 학습도 가능하게 계획하였다. 교수, 학습의 복합화에 대처하여 칸막이를 이동 가능한 형태로 계획하였으며, 일반 교과도 컴퓨터를 이용한 수업이 가능하게 정보 코너를 설치하였다. 지역사회인에게 열린 교실이 되게 계획하였고 개별 학습이 가능한 구조로 계획하교 기자재의 선진화를 대비한 학습 환경의 제고도 고려하였다. 본 연구의 입면 형상은 주변 건물과 조화되게 수평적 요소가 강조되는 형상이 되도록 계획하며 고층의 아파트의 위협을 상쇄시키기 위하여 지붕이 있는 구조로 계획하여 지역사회에서 중심임을 강조하도록 계획하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.63-69
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• 2011

This study analyzes stress, fatigue and vibration on main rotor and body of helicopter. The maximum stress is shown on adjoint part between body and main rotor at the lower position of main rotor. As the maximum displacement amplitude is happened at 4000Hz, there is no resonance and the state of helicopter becomes safe at hovering without the abnormal air current and the disabled rotor. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample History' with the average stress of 0MPa to $-10^5MPa$ and the amplitude stress of 0MPa to $8.539{\times}10^5MPa$, the possibility of maximum damage becomes 3%. This stress state can be shown with 5 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study by using the analysis of vibration and fatigue can be effectively utilized for safe and durable design of helicopter.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.130-134
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• 2011

This study aims at the structural safety with optimum design of automotive bumper in order to minimize the maximum stress and displacement and reduce the minimum quantity of bumper material. As the forces of X and Y direction increase, equivalent stress and displacement increase. The displacement of X direction force increases more than 20% in comparison with Y direction force. But the equivalent stress of Y direction force increases more than 60% in comparison with X direction force. The mass of inner bumper becomes minimum and the mass of outer bumper becomes maximum when the force of 4000N is applied on the direction inclined at $45^{\circ}$ toward outer bumper. In 50% range of increase and decrease at X and Y direction force, the optimum forces of X and Y component becomes 2368.8N and 1538.8N respectively. And the masses of inner and outer polypropylene bumper become $3.3227{\times}10^{-2}kg$and $3.5538{\times}10^{-2}kg$respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.477-482
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• 2009

This study analyzes the result with dynamic simulation about deformation according to time when a car impacts bollard. These results are shown as followings. The maximum deformation is shown at the lower part of front grass in case of the impact of front or passenger seat but this deformation is shown at the lower part of rear bumper in case of double impact. The maximum equivalent stress is shown at the upper part by the side grass of driver seat at the elapsed time of 0.00075 second after impact in case of the impact of front or passenger seat but this deformation is shown at the front bonnet at the elapsed time of 0.004 second after the additional impact in case of double impact. The maximum total deformation or equivalent stress is shown nearly same in case of the impact of front or passenger seat. But the value of this deformation or equivalent stress in case of the impact of front or passenger seat is shown with 2 times or more than 17% respectively as this value in case of double impact.