• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.947-950
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• 2001

We report the characteristics of organic light emitting diodes (OLEDS) by controlling the carrier mobility according to the crystalline of Iron(II) Phthalocyanine(Fe-Pc) and metal-free Phthalocyanine (H$_2$-Pc). In order to change the recombination zone, we controlled the hole mobility by changing the crystal structures of Fe-Pc and H$_2$-Pc. OLEDs were constructed with ITO/Fe-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al and ITO/H$_2$-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al. The electroluminescent properties were changed according to the heat-treatments of Fe-Pc and H$_2$-Pc. We observed that the recombination zone and the carrier mobility were changed as the higher occupied molecular orbital levels of Fe-Pc and H$_2$-Pc decreased.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.79-92
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• 2015

In this study, free vibration analyses of symmetric laminated cantilever and simply supported damaged composite beams are investigated by using finite element method (FEM). Free vibration responses of damaged beams are examined using Euler Bernoulli beam and classical lamination theories. A computer code is developed by using MATLAB software to determine the natural frequencies of a damaged beam. The local damage zone is assumed to be on the surface lamina of the beam by broken fibers after impact. The damaged zone is modeled as a unidirectional discontinuous lamina with $0^{\circ}$ orientations in this study. Fiber volume fraction ($v_f$), fiber aspect ratio ($L_f/d_f$), damage length ($L_D$) and its location (${\lambda}/L$), fiber orientation and stacking sequence parameters effects on natural frequencies are investigated. These parameters are affected the natural frequency values significantly.

• 한국레이저가공학회지
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• 제4권3호
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• pp.30-39
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• 2001

This work was tamed out to apply a laser welding technique in joining between a Zn coated low carbon steel plate(SECC) and a free cutting carbon steel shaft(SUM24L) with or without W coating. Experiments were carried out and analysed by applying the FD(factorial design)method to obtain the optimum Laser welding condition. Optical microscopy, SEM, TEM and XRD analyses were performed in order to observe the microstructures in the fusion zone and the HAZ. Mechanical properties of the welded specimens were examined by microhardness test, tensile test and twist test. There was no flawed Zn in the fusion zone by EDS analysis. This means that during the welding process, Zn gas could be eliminated by appropriate shielding gas flow rate and butt welding gap. Ni coating itself did not influence on the tensile strength and hardness. However, twist bending strength and the weld depth of the Ni-coated free cutting carbon steel were lower as compared with those of the uncoated free cutting carbon steel. It was attributed to a lower absorbance of laser beam to the shin Ni surface. According to the results of the factorial design tests, the twist bending strength of welded specimens was primarily affected by pulse width, laser power, frequency and speed.

• 대한치과교정학회지
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• 제22권2호
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• pp.309-325
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• 1992

The purpose of this study was to evaluate the effect of intrinsic factor and extrinsic factor for growth of the mandibular condylar cartilage of 4 day-old rats in a serum-free medium for 1, 4, 7, 14 days. They were compared with normal growth in vivo and with growth of spheno-occipital synchondrosis in serum-free medium. The cellular kinetics of cartilages were evaluated by auto-radiography of tritiated thymidine. 1. Condylar cartilage was enlarged with rounded head on day 14 of experiment while in vivo the rounded-headed shape changed into functionally flattened appearance. 2. On day 14 of experiment, a severe reduction of the proliferative zone and a considerable increase of the hypertrophic zone were observed while in normal control group endochondrol bone formation and bone marrow were observed. 3. The proliferative activity in the proliferative zone of condylar cartilage detected by $^3H-thymidine$ incorporation was lower than that of normal control group and decreased more than that of spheno-occipital synchondrosis, but it continued during the 14 days of culture. 4. The continued maintenance of condylar cartilage and morphologic change were disturbed in this culture system, but cell division within the proliferative zone was continued and probably linked to intrinsic factor.

• 유통과학연구
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• 제12권9호
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• pp.113-123
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• 2014

Purpose - After Korea's Free Economic Zone (FEZ) system was launched in 2003, there have been many debates about upgrading it and its support systems. However, as of 2013, there were insufficient results. Further, upon the designation of the East Coast and Chungbuk as official FEZs from February 4, 2013 by the 56th the Commission, there is a concern that many people are in the area designated as FEZ 8. This study investigates Korea's new FEZ system as part of Korea's primary new economic development policy in the 21st century. Therefore, this study examines views on the weaknesses of the past ten years of FEZs so that Korea can expand its FEZ system. Research design, data, and methodology -Many countries have considered the FEZ as an economic special zone. By reviewing previous research models, this study provides an update using recent data and materials, until 2013, from the Center of Free Economic Zones. In previous studies, the lack of support systems was attributed to proposals to ensure operational autonomy and differentiation of each FEZ; however, the main cause cannot be solved through regulatory issues, as difficulties caused by the operational system are responsible for the problems. We wish to analyze the FEZ, specifically the operational system; this is the main issue of this study. Results - After the first FEZs were established, it became necessary to have basic plans, as investment results in 2013 compared to the same period this year led to lower earnings in the first half of 2014. We propose an improvement of the operational system because in the free economic zones, the operational system is the root cause of the underlying problem. The results of this research are as follows. The weak management of the FEZ system is influenced by weak investment, delayed development, foreigners' living facilities, benefits of foreign investments, the control tower's policy making decision process, quickness of the process of satisfying legal requirements, and support For the independence of FEZs. Conclusion - Local governments do not have legal rights over FEZ deregulation and investment industries. This study suggests that the local government should have more independence from the central government. Moreover, independent management committees are more effective for ensuring public rights, better employee responsibilities, and better-qualified personnel. The FEZ committee struggles to effectively manage the locations of FEZs, foreign investments, and related facilities under the control of the Ministry of Trade, Industry and Energy. Thus, the FEZ committee should be under either the Prime Minister's office or the Presidential committee, to control and effectively coordinate between the local and central governments. If the problem clearly applies to the operational system in 2013, it is necessary to provide materials and methods so that the results of the first half of 2014 can be computed despite the data limits and lack of resources, and the data can be analyzed in a more diachronic thesis.

• 한국중재학회지:중재연구
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• 제18권1호
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• pp.121-145
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• 2008

Northeast Asia is increasingly making a transition to distinctive and crucial region in the 21st Century and growing into one of world's top three economic spheres along with the EU and NAFTA. In 2003, Korean government announced the Northeast Asian economic hub country plan as an important agenda. As a means of coping with the changing global environment, Korean government designated Incheon in 2003 as the country's first Free Economic Zone ahead of Busan and Gwangyang Bay in the south of the country because Incheon has a geographical advantage linking North America and Europe with Incheon International Airport and Incheon Seaport. The purpose of this paper is to make research on establishment and operation of an arbitral body entitled ${\ulcorner}International Arbitration Center{\lrcorner}$ (IAC) within Incheon Free Economic Zone(IFEZ). For the purpose of this, the writer in this paper, reviewed the necessity of the IAC's establishment and its legal basis as well as the role and function of the Center. Also, the writer presented plans for how to operate the IAC and how to cooperate with the key arbitral organizations of foreign countries for the settlement promotion of commercial disputes including trade and investment. With development of the IFEZ, world-renowned enterprises will invest in the Incheon economic bloc and conduct economic activities, business operation, marketing, logistics, financing, etc. In this connection, diverse types of commercial disputes are expected to occur between foreign companies entering the IFEZ and Korean firms. In this connection, the Korean Commercial Arbitration Board(KCAB) has been operating its liaison office in the IFEZ since 2004. However, in view of the increasing arbitration demand, the IAC should be set up in the IFEZ in the near future by the positive support of the government in the respect of both administration and finance because the free economic zone-related law provides for the installation of arbitration organization. For the success of the IAC, the Center will have to provide not only good quality of arbitral services that can satisfy arbitration parties but also need to conduct researches and make efforts so that arbitration can be utilized well in the IFEZ. If the IFEZ can provide advantageous business environments to those multinational enterprises intending to the Incheon economic bloc, the IAC will also contribute to the settlement of commercial disputes arising from the Gaeseong Industrial Complex in North Korea in view of the geographical advantage and logistic benefit of the IFEZ. Finally, this paper also suggests a new model for a joint dispute resolution system by the initiative of Korean government and Korean arbitral organizations for the settlement of commercial disputes within Northeast Asia, for which the CAMCA(Commercial Arbitration and Mediation Center for the Americas) of NAFTA can be a good example.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 봄 학술발표회 논문집
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• pp.35-41
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• 1995

Fracture Mechanics does work for concrete, provided that a finite nonlinear zone at fracture front is being considered. The development of model for fracture process zone is most important to describe fracture phenomena in concrete. The fracture process zone is a region ahead of a traction-free crack, in which two major mechanisms, microcracking and bridging, play important rules. The toughness due to bridging is dominant compared to toughness induced by microcracking, so that the bridging is dominant mechanism governing the fracture process of concrete. In this paper the bridging zone, which is a part of extended macrocrack with stresses transmitted by aggregates in concrete, is model led by a Dugdale-Barenblatt type model with linear tension-softening curve. Two finite element techniques are shown for the model of fracture process zone in concrete.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.521-527
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• 2020

해양구조물에서 점성효과를 고려하여 항력에 기인한 평균 점성 표류력를 구하는 것은 최근까지 잘 고려되지 않았던 설계 요소이다. 특히 저주파 영역에서 파랑과 조류를 모두 고려한 수직 실린더에 작용하는 평균 점성 표류력에 대해 계산하는 것이 가장 중요하다. 따라서 본 연구에서는 파랑과 조류를 고려한 고정된 수직 실린더 구조물에 작용하는 평균 점성 표류력에 대해 해석적 수식 해를 도출하는 과정을 구체적으로 제시하였다. 실린더의 수면 위로 나온 부분을 Splash Zone, 수면 아래의 잠긴 부분을 Submerged Zone으로 구분하였다. 파랑이 존재하는 경우는 Splash Zone에서만 고려되고, 파랑과 조류를 포함한 경우는 Splash Zone과 Submerged Zone 모두에서 각각 식을 구하였다. Splash Zone 및 Submerged Zone에서 모두 상당한 점성 효과로 기인한 표류력이 발생한다. 따라서 본 연구에서 도출한 해석적 해를 통해 주어진 설계 변수들에 의한 평균 점성 표류력을 계산할 수 있으며, 각각의 Case에 해당하는 표류력의 크기가 구체적인 물리적인 범위 내에서 주도적인 영향을 끼치는지 판단할 수 있는 이론적 근거를 제시할 수 있다.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.503-509
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• 2020

Semi-submergible, Tension-leg Platform 등과 같은 부유식 해양구조물에서 점성효과를 고려하여 항력에 기인한 점성 표류력를 구하는 것은 최근까지 잘 고려되지 않았던 설계 요소이다. 본 논문에서는 파랑과 조류를 고려한 부유식 수직 실린더 구조물에 작용하는 평균 점성 표류력에 대한 해석적 수식 해를 구하였다. 기존의 고정된 실린더에서 구한 방식과 같이 실린더의 수면 위로 나온 부분을 Splash Zone, 수면 아래의 잠긴 부분을 Submerged Zone 으로 구분하였다. 파랑이 존재하는 경우는 Splash zone 에서만 고려되고, 파랑과 조류를 포함한 경우는 Splash Zone 과 Submerged Zone 모두에서 각각 식을 구하였다. 기존 연구의 RAO 결과값을 활용하여 고정된 실린더에 작용하는 평균 점성 표류력의 계산 결과와 비교하였다. Splash Zone에서 파랑만 존재하는 경우를 제외하고 대부분의 주파수 영역 대에서 부유식 실린더에 작용하는 평균 점성 표류력의 크기가 상대적으로 고정된 실린더에 작용하는 표류력의 크기보다 크게 나오는 것을 볼 수 있으며, 특히 조류가 상대적으로 더 중요하게 고려되는 경우 더 크게 증가함을 알 수 있었다. 따라서, 본 연구 결과를 통해 부유식 해양 구조물 설계시 항력으로 인한 점성 표류력의 추론을 제시할 수 있다.

• 한국항해항만학회지
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• 제29권7호
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• pp.611-614
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• 2005

This paper is to develop the position error equation of in the free-gyro positioning system by using two free gyros. First, the determination of a position is analyzed on the ellipsoid of the Earth and the type of the errors is defined Finally the position error equation is introduced and developed, based on the definition of the type of errors which may be involved in the FPS.