• 동력기계공학회지
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• 제7권2호
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• pp.44-50
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• 2003

The power steering hose is a kind of high-pressure hose with reinforced braids in rubber material. It is usually manufactured through the swaging process. In this paper, the deformation characteristics of a power steering hose during the swaging process were analyzed using the nonlinear finite element method. The material properties were obtained on experiments, and the contact conditions were used in consideration of real manufacturing process. Investigations were focused on the stress and strain values of the hose and meta] components at the maximum jaw stroke and at the completion of the process. Especially, the results of inner rubber component were interpreted in detail, because of its important role in the hose efficiency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.931-934
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• 2001

GaN nanowires has much interest as one-dimensional materials for blue light LED. GaN-based materials have been the subject of intensive research for blue light emission and high temperature/high power electronic devices. In this letter, the synthesis of GaN nanowires by the reaction of mixture of GaN nanowires by the reaction of mixture of Ga meta and GaN powder with NH$_3$ using thermal chemical vapor deposition is reported. X-ray diffraction, energy dispersive x-ray spectrometer, scanning electron microscopy, and transmission electron microscopy indicate that those GaN nanowires with hexagonal wurtzite structure were about 60nm in diameter and up to several hundreds of micrometers in length.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.63-63
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• 2010

나노 구조를 제작은 나노 기술을 기반으로 하는 electronics, optoelectronics, sensing, ultra display등의 여러 분야에서 이용되고 있다. 특히 나노 구조를 갖는 금속 패터닝의 경우 전자빔 리소 그래피 (electron beam lithography)나 레이저 패터닝(laser patterning)과 같은 방법들이 많이 사용되고 있다. 하지만 공정이 복잡하고 그로 인해 공정 비용이 많이 든다는 단점이 있었다. 나노 임프린트 리소그래피 기술은 master mold 표면의 나노 패턴을 가열, 가압 공정을 통해 기판 위의 고분자 레지스트 층으로 전사하는 기술이다. 이 기술은 간단한 공정을 통해 나노 패턴을 형성할 수 있는 기술이기 때용에 차세대 나노 패터닝 기술로써 각광받고 있다. 특히 이 기술은 레지스트 층과의 직접적인 접촉을 통해 나노 패턴을 형성하기 때문에 다양한 방법을 통해 기능성 나노 패턴을 직접적으로 형성할 수 있는 가능성을 지니고 있다. 본 연구는 novel meta1의 하나인 Ag 입자가 첨가된 ink solution를 master mold로부터 복제한 PDMS mold를 이용하여 다양한 구조의 나노 패턴을 만드는 방법에 대한 연구이다.

• Structural Engineering and Mechanics
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• 제51권3호
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• pp.361-375
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• 2014

The main aim of this paper is to investigate the relationship between thickness and height of the axially symmetric cylindrical reinforced concrete (RC) walls by the help of a meta-heuristic optimization procedure. The material cost of the wall which includes concrete, reinforcement and formwork, was chosen as objective function of the optimization problem. The wall thickness, compressive strength of concrete and diameter of reinforcement bars were defined as design variables and tank volume, radius and height of the wall, loading condition and unit cost of material were defined as design constants. Numerical analyses of the wall were conducted by using superposition method (SPM) considering ACI 318-Building code requirements for structural concrete. The optimum wall thickness-height relationship was investigated under three main cases related with compressive strength of concrete and density of the stored liquid. According to the results, the proposed method is effective on finding the optimum design with minimum cost.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.309-310
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• 2007

Spacecrafts such as most of commercial satellites that are operating in the geostationary orbit can be subjected to intense irradiation by charged particles. The surface made of dielectric materials can therefore become probable sites for damaging electrostatic discharges. Thanks to a specially equipped chamber, the spatial environment can be reproduced experimentally in the laboratory. In this paper, the behavior of high energy electrons injected in polymers such as PolyMethylMetaAcrylate (PMMA) and Kapton is studied. Results obtained by surface potential technique, pulse-electro acoustic device and a cell based on the split Faraday cup system are analyzed and discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.621-624
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• 1999

Metalization technology of the fine patterns by electroless plating is required in place of electrodeposition as high-density printed boards(PCR) become indispensable with the miniaturization of electronic components. Electroless nickel plating is a suitable diffusion barrier between conductor meta1s, such as Al and Cu and solder is essetional in electronic packaging in order to sustain a long period of service. Moreover, Electroless nickel has particular characteristics including non-magnetic property, amorphous structure. wear resistance, corrosion protection and thermal stability In this study fundamental aspects of electroless nickel deposition were studied with effort of complexeing agents of different kinds. Then the property of electroless deposit are controlled by the composition of the deposition solution the deposition condition such as temperature and pH value and so on. the characteristics of the deposits has been carried out.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.95-102
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• 2012

고층건축물의 구조부재로 적용되는 철골이나 고강도콘크리트로 시공된 경우 내화대책은 필수 불가결한 요소이며 특히, 고강도콘크리트로 적용된 경우 폭렬 등에 의한 단면결손이 발생하기 쉽기 때문에 이에 대한 대책이 필요하다. 즉, 내화성능 확보를 위해 온도상승을 허용범위 이내로 억제하는 대책이 필요하며 이 중 가장 효율적인 방법이 내화성 마감을 실시하는 것이다. 일반적으로 내화성 마감재에 사용되는 시멘트계 재료는 C-S-H, 및 CH가 단계적으로 열 분해되어 압축강도는 저하하게 된다. 내화성능을 발휘하기 위해 고온에서 강도감소가 작고 안정적인 고온특성을 보인다면 보다 효과적으로 성능 발현이 가능할 것이다. 본 연구는 고층건축물의 철골 및 콘크리트 부재의 효과적인 내화성능 발현을 위한 경량 내화성 마감재 개발을 위한 연구로 내화성능이 우수하다고 알려진 Alumino-silicate계 재료를 내화성 마감에 적용하기 위해 고온특성에 대해 검토하였다. 검토 결과, 플라이애시, 메타카올린 및 경량골재를 활용한 경량 내화성 마감재는 고온에서 비교적 안정적인 특성을 발현하여 내화성 마감재로의 효용성을 확인할 수 있었다.

• 한국학교수학회논문집
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• 제3권1호
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• pp.131-148
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• 2000

Above all, the ability to solve problems must be emphasized as a basic skill of mathematics, but it is neglected when we teach. In this study, learning task means ［same meaning］ ［same form］ ［same technique］, so I tried to extend mathematical scholastic ability of the students as an extensional problem solving that is a basic element of mathematics. The purpose of this study is the investigation of level type learning, using the basic learning elements to extend thinking ability. From the constructed hypothesis as follows and then implement it. I selected basic learning elements from an analyzed textbook and then task learning material was created for each level type learning. The problem solving ability will be extended through the level type learning of the small group, using the level type learning task material. The conclusions this study are as follows. The level type learning in small group learning, using and making level type learning material, having basic learning elements in analysed text are. Basic learning content is understood clearly and deeply, so, fundamentally, it is effective in achieving the problem solving in mathematics. It is an effective method to achieve the meta-cognitive faculty because achieved the expected method of solving problems and resulted in the true learning of content.

• 한국산학기술학회논문지
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• 제18권12호
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• pp.466-472
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• 2017

본 연구의 목적은 곰팡이 28S rDNA 염기서열의 메타분석을 통하여 반추위 곰팡이의 다양성을 조사하는데 있다. 'rumen'과 'ruminal'이 반추위 곰팡이 유래 염기서열들을 회수하기 위한 검색어로 사용되었다. 2016년 9월부로 모든 28S rDNA 염기서열이 보관되어 있는 Ribosomal Database Project(RDP, http://rdp.cme.msu.edu) 데이터베이스에서 반추위 곰팡이 유래 28S rDNA 유전자 염기서열(n=165)을 획득하였다. 총 165개의 염기서열은 분류학상의 '문(phylum)'인 Ascomycota, Neocallimastigomycota 및 Basidiomycota로 분류되었고, 165개의 염기서열 중에서 각각 109개, 48개, 8개의 염기서열을 차지하였다. Ascomycota 염기서열은 식물병원성곰팡이나 마이코톡신을 생성하는 곰팡이를 포함하고 있는 '속(genus)' Pseudonectria, Magnaporthe, Alternaria, Cochliobolus, Cladosporium 및 Davidiella로 분류되었다. 또한, Basidiomycota 염기서열은 식물병원성곰팡이를 포함하고 있는 '속(genus)' Thanatephorus와 Cryptococcus로 분류되었다. 뿐만 아니라, Neocallimastigomycota 염기서열의 경우 섭취된 조사료의 주요 구조탄수화물을 분해하는 '속(genus)' Cyllamyces, Neocallimastix, Anaeromyces, Caecomyces, Orpinomyces, Piromyces로 분류되었다. 본 연구는 처음으로 28S rDNA 염기서열의 메타분석을 통해 반추위 곰팡이 다양성에 대한 정보를 통합적으로 제공하였다. 본 연구의 결과는 향후 반추위 곰팡이 연구에 대한 방향을 제공할 것이고, 새로운 분석도구 개발에 응용될 수 있을 것이다.

• 동의신경정신과학회지
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• 제32권3호
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• pp.185-206
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• 2021

Objectives: The objective of this study was to perform a systematic review and meta-analysis of pharmacopuncture treatment for insomnia disorder to derive clinical evidence and recommendation grades. Methods: Studies that verified effects of pharmacopuncture on primary insomnia were included. Characteristics and quality of included studies were assessed using Risk of Bias (RoB). Results: A total of 25 studies were selected. Pittsburgh Sleep Quality Index (PSQI) and effective rate were primarily used for outcome measurement. Vitamin B12 was the most used pharmacopuncture material. The most frequently used acupuncture point was Anmian (Ex-HN). The volume of the acupuncture solution ranged from 0.25 mL to 2 mL. Acupuncture treatment depth was 0.5 cm to 2 cm. In three studies, the procedure was performed at 16:00. Meta-analysis of studies revealed that the effective rate of the pharmacopuncture group was significantly higher than the group using sleeping pills group (RR: 1.21, 95% CI: 1.01 to 1.45, p=0.04, I²=69%). PSQI was decreased in the intervention group (MD=-2.19, 95% CI: -2.90 to -1.48, p<0.00001, I²=0%). Effective rates of pharmacopuncture and acupuncture groups were higher than that of the acupuncture group (RR: 1.11, 95% CI: 1.05 to 1.17, p=0.0002, I²=0%). PSQI was decreased in the intervention group (MD=-1.87, 95% CI: -2.36 to -1.38, p<0.00001, I²=0%). Although the effectiveness rate of the pharmacopuncture group was not significantly higher than that of the acupuncture group (RR: 1.12, 95% CI: 0.98 to 1.27, p=0.1, I²=9%), the PSQI was decreased in the pharmacopuncture group (MD=-2.10, 05% CI: -3.29 to -0.91, p=0.0005, I²=34%). The quality of clinical studies was poor. Conclusions: Based on results of this study, it is proper to use 0.5 to 2 mL of pharmacopuncture solution such as Danshen and Ciwujia with a depth of 0.5 to 2 cm at around 4 p.m. to treat insomnia disorder, focusing on Anmian (Ex-HN) and Sameumgyo (SP6).