• 비파괴검사학회지
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• 제19권1호
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• pp.8-15
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• 1999

교류전위차법 (alternating current potential drop : ACPD)을 이용하여 이차원 표면균열을 갖고 있는 강자성체 (ferromagnetic material)와 상자성체 (paramagnetic material)의 모드 I (opening mode) 응력확대계수($K_I$)를 효과적으로 계측하는 방법을 개발하기 위하여 하중에 따른 교류전위차 변화(change in ACPD)에 미치는 자속(magnetic flux)의 영향을 연구하였다. 그리고 하중에 따른 전위차 변화에 미치는 탈자(demagnetization) 및 균열길이의 영향을 연구하였다. 기전력을 많이 유도할 수 있도록 설계된 계측계의 경우 하중에 따른 교류전위차 변화량은 크게 증가하였다. 아울러 교류전위차 변화와 응력확대계수 변화 사이의 관계는 탈자 등의 조치가 없어도 선형적이며, 탈자는 전위차 변화에 거의 영향을 미치지 않았다. 일정 $K_I$ 변화에 의한 전위차 변화량은 균열길이에 의존하지 않고 계측계에 의존한다. 교류전위차법을 이용하여 효과적으로 응력확대계수를 결정하는 방법은 기전력을 많이 유도할 수 있도륵 설계된 계측계를 사용하여 교류전위차 변화를 측정하는 것이다.

• 한국화재소방학회논문지
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• 제30권4호
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• pp.82-87
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• 2016

초고층 건물의 환기계획에서 설비의 효율적인 운영을 위해 환기설비는 제연설비 겸용으로 사용되고 있다. 본 연구에서는 지하 4층 지상 59층의 초고층 건물을 분석모델로 선정하고 수치해석을 통해 연기이동력에 의한 층별 압력분포를 검토하였으며, 분석모델 건물에서의 연기이동력이 환기 및 제연에 미치는 영향을 규명하였다. 또한 이들 결과를 바탕으로 분석모델 건물의 환기계획에서 주방용 환기댐퍼를 환기-제연 겸용으로 설계할 때 연기이동의 복합력과 요구되는 댐퍼의 개폐력과의 관계를 운동해석 시뮬레이션을 통해 결정하였고, 그 결과로부터 적합한 댐퍼의 구동장치를 선정하였다.

• 대한치과교정학회지
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• 제50권1호
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• pp.42-51
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• 2020

Objective: The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion. Methods: Sixty male Sprague-Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated. Results: TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group. Conclusions: Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.208-208
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• 2013

Graphene has emerged as a fascinating material for next-generation nanoelectronics due to its outstanding electronic properties. In particular, graphene-based field effect transistors (GFETs) have been a promising research subject due to their superior response times, which are due to extremely high electron mobility at room temperature. The biggest challenges in GFET applications are control of carrier concentration and opening the bandgap of graphene. To overcome these problems, three approaches to doping graphene have been developed. Here we demonstrate the decoration of Ni nanoparticles (NPs) on graphene films by simple annealing for p-type doping of graphene. Ni NPs/graphene films were fabricated by coating a $NiCl2{\cdot}6H2O$ solution onto graphene followedby annealing. Scanning electron microscopy and atomic force microscopy revealed that high-density, uniformly sized Ni NPs were formed on the graphene films and the density of the Ni NPs increased gradually with increasing $NiCl2{\cdot}6H2O$ concentration. The formation of Ni NPs on graphene films was explained by heat-driven dechlorination and subsequent particlization, as investigated by X-ray photoelectron spectroscopy. The doping effect of Ni NPs onto graphene films was verified by Raman spectroscopy and electrical transport measurements.

• The Korean Journal of Ecology
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• 제22권1호
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• pp.31-37
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• 1999

1997년 4월부터 6월 사이에 전북 전주시 천잠산에서 외줄면충(Paracolopha morrisoni Baker, 1919)의 충영 형성과 1차 기주식물인 느티나무 잎의 생장과의 관계를 조사하였다. 외줄면충은 느티나무 가지의 3∼4번째 잎에 많이 분포하며, 주로 잎의 하단 엽맥에 충영을 형성하였다. 충영은 4월 20일 경에 형성되기 시작하였으며, 4월 23일에는 길이(2.98 mm)와 폭(2.24 mm)이 비슷하였으나 길이의 생장이 빨라져 5월 12일에는 길이(11.05 mm)와 폭(6.60 mm)이 최대로 생장하였는데 이는 잎의 길이 생장과 매우 밀접한 상관관계를 나타내었다. 충영을 절개하여 외줄면충의 발육상황을 조사한 결과, 간모가 3번 탈피하여 5월 8일에 간모 성충이 100% 나타났으며 제2세대를 체내에 간직하고 있었다. 5월 19일에는 간모 성충의 84.8%가 사망하였다. 제2세대인 이주형은 5월 12일에 약충이 나타나기 시작하였고 5월 하순에 4회 탈피하여 6월 3일에는 유시 성충이 나타났다. 6월 7일에는 충영의 기부가 열려 유시 성충이 탈출하고 그 후 충영은 갈색으로 변하여 쇠퇴하였다. 이상의 충영 형성과정을 볼 때 간모 세대가 충영의 형성과 생장에 관여하며 제2 세대는 충영의 생장과 관계가 없었다.

• 대한치과교정학회지
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• 제50권3호
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• pp.206-215
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• 2020

Osteochondroma is a common benign tumor of bones, but it is rare in the mandibular condyle. With its outgrowth it manifests clinically as deviation of the mandible limitation of mouth opening, and facial asymmetry. After the tumor is diagnosed on the basis of clinical symptoms and radiographic examination including cone-beam computed tomography (CBCT) analysis, an appropriate surgery and treatment plan should be formulated. Herein, we present the case of a 44-year-old female patient who visited our dental hospital because her chin point had been deviating to the left side slowly but progressively over the last 3 years and she had difficulty masticating. Based on CBCT, she was diagnosed with skeletal Class III malocclusion accompanied by osteochondroma of the right mandibular condyle. Maxillary occlusal cant with the right side down was observed, but it was confirmed to be an extrusion of the molars associated with dental compensation. Therefore, after intrusion of the right molars with the use of temporary anchorage devices, sagittal split ramus osteotomy was used to remove the tumor and perform orthognathic surgery simultaneously. During 6 months after the surgery, continuous bone resorption and remodeling were observed in the condyle of the affected side, which led to a change in occlusion. During the postoperative orthodontic treatment, intrusive force and buccal torque were applied to the molars on the affected side, and a proper buccal overjet was created. After 18 months, CBCT revealed that the rate of bone absorption was continuously reduced, bone corticalization appeared, and good occlusion and a satisfying facial profile were achieved.

• 한국항만학회지
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• 제13권2호
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• pp.313-322
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• 1999

Pusan the principal port of South Korea, has opened its door since 1876. Currently, the four-stage port construction project is under way to handle ever-growing marine transportation volume. While the port unloading capabilities are increasing the infrastructure to deal with all the transportation volume failed to catch up with them. Accordingly the city had to suffer from worst traffic congestion on due to the increasing container traffic volume causing logistical costs to rise. This study was designed to inspect the enforcement of infrastructure construction plan and suggest systematical and effective ways to improve the plan. The study focused on :\circled1The decision-making procedure, \circled2Financial resource for the plan, \circled3Effectiveness of the project enforcement, and \circled4Who will be in charge of the project. As a result from the study, these followings were suggested to improve the plan. First, Pusan Port Infrastructure consisting of (Inter-city Free way, Belt Highway and Outer Highway) should be immediately legally-regulation project. Second, the method to finance the project should be deter-mined and investment consultation among the central government the city government and private sector should be also made. Measures to make the central government budget allocation for the project mandatory should be discussed. Third, Effectiveness of the project can be doubled by gradually or partialyl opening the routes based on long-term or short-term operating plans. Fourth, The organizer of the project should be appointed, or a special task-force team in charge of the plan can be formed.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1741-1751
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• 2004

It is commonly requested that the steam generator tubes wall-thinned in excess of 40% should be plugged. However, the plugging criterion is known to be too conservative for some locations and types of defects and its application is limited to a single crack in spite of the fact that the occurrence of multiple through-wall cracks is more common in general. The objective of this research is to propose the optimum failure prediction models for two adjacent through-wall cracks in steam generator tubes. The conservatism of the present plugging criteria was reviewed using the existing failure prediction models for a single crack, and six new failure prediction models for multiple through-wall cracks have been introduced. Then, in order to determine the optimum ones among these new local or global failure prediction models, a series of plastic collapse tests and corresponding finite element analyses for two adjacent through-wall cracks in thin plate were carried out. Thereby, the reaction force model, plastic zone contact model and COD (Crack-Opening Displacement) base model were selected as the optimum ones for assessment of steam generator tubes with multiple through-wall cracks. The selected optimum failure prediction models, finally, were used to estimate the coalescence pressure of two adjacent through-wall cracks in steam generator tubes.

• Korean Chemical Engineering Research
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• 제43권3호
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• pp.331-343
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• 2005

연료전지와 수소를 사용하는 연료전지 자동차의 상용화를 위해서는 수소 공급용 수소 스테이션(hydrogen station)의 개발이 중요한 핵심 기반기술이다. 일반적으로 수소 스테이션은 탈황반응, 개질반응(reforming), 수성가스전환(WGS) 반응 및 수소분리(PSA) 장치로 구성된 수소제조 공정과 압축, 저장 및 분배 장치로 구성된 후처리(post-treatment) 공정으로 구성되어 있다. 본 총설에서는 수소 경제(hydrogen economy) 사회로의 진입을 위해 국내외에서 연구개발 중인 수소 스테이션에 대한 연구 개발 동향과 전망을 고찰하였다. 그리고 향후 풍력 및 태양열 등 재생 가능 에너지(renewable energy)원으로부터 물의 분해에 의한 수소제조 기술이 확립되기 전까지는 화석연료의 개질 반응이 수소를 제조하는 핵심기술이 될 것으로 판단된다. 따라서 화석연료의 탈황반응, 화석연료의 개질 반응에 의한 수소제조, CO 농도 저감을 위한 수성가스 전환반응 및 수소의 분리기술 등 수소 스테이션의 상용화에 필수적인 단위공정개발에 대한 최근의 연구동향을 정리하였다.

• 대한예방한의학회지
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• 제12권2호
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• pp.73-83
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• 2008

The rapid change of the health and medical environment and the globalization of medicine has driven doctors to converge and analyse of new and up-to-date medical information and decide to what to make decision for diagnosis and treatments in clinical practice. Medical environment goes with the changes with social environment such as rapid increase of aging population, changes of disease pattern, formation of new area of experts except doctors, government intervention for the medical system, medical insurance of the charges of medical treatment, a increased desire for human rights. These trends should be adopted rapidly to the education system for the students of medical school. The learning objectives of the preventive medicine was developed in 1995 and underwent necessary revision of the contents to create the first revision in 2006. However, the required educational contents of health promotion and disease prevention have been changed by the new trends of medical education such as PBL and integrated curriculum and the 2006 revision does not satisfy these needs. We formed a task force which surveyed all the Western and Traditional Korean medical colleges to describe the state of preventive medicine education in Korea, analyzed the changing education demand according to the change of health environment and quantitatively measured the validity and usefulness of each learning objective in the previous curriculum. With these results, for the good education for preventive medicine, each Traditional Korean medicine schools need more preventive medicine faculties and teaching assistants and opening of some required subjects such as Yangsaeng and Qigong. And future studies of the learning process and ongoing development of teaching materials according to the new learning objectives should be undertaken with persistence in order to ensure the progress of preventive medicine education.