• International Journal of Highway Engineering
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• v.3 no.4 s.10
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• pp.117-126
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• 2001

In this research, evaluation of adhesion in tension property of SBR-modified concrete to ordinary portland cement concrete was conducted with uniaxial direct tensile bond test which was proposed by Kuhlmann. A test set-up was fabricated in order to minimize the eccentric force by introducing a joint which might fully rotate. The main experimental variables were cement-latex ratios, surface preparations and moisture levels. The results obtained were as follows: The LMC specimen at 15% latex-cement ratio increased the adhesion in tension by range of 37% compared to that of conventional cement concrete. This might be due to latex film formed between cement paste and aggregate. The effects of surface preparation on bond of latex modified concrete to conventional concrete were significant at the conditions by sand paper and wire brush. A better bond could be achieved by rough surface rather than smooth. The saturated and surface dry (SSD) condition were considered to be the most appropriate moisture level followed by wet, finally by dry. Thus, a proper surface preparation and moisture level are quite necessity in order to obtain better bonding at LMC overlay.

• 한국사회복지학회:학술대회논문집
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• 2002.04a
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• pp.497-531
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• 2002

It is very important for rehabilitation to deal with psychological aspects of persons with disabilities, as well as efforts improving the institutional and environmental conditions. A majority of persons with severe disabilities in the situation of Korea have difficulty in having and maintaining a job. Work should and would be a source of self-respect and material well-being in this modern society. Therefore, Vocational rehabilitation services are measures in restoration of family functions and social participation of persons with disabilities. This study aims at investigating linguistic characteristics and the validity of constructional concepts of picture interest test Inventories that have been utilized for the segregated groups of people such as persons with developmental disabilities. Picture interest test inventories seemed to be valid for measuring psychological traits and characteristics of people with mental retardation, and this finding can be extended to the group of other developmental disabilities, such as learning disabilities and mild/moderate behavioral deficits. The Holland classification system seemed to be best fitted for developing a comprehensive and accurate vocational interest inventory.

• Journal of Korean Home Economics Education Association
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• v.27 no.3
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• pp.35-46
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• 2015

This study investigates the level of middle school students' achievement perceptions of the objectives of Home Economics education. A survey was conducted using a convenient sample from 360 middle school students, and 332 subjects were used in the final analysis. First, the level of achievement perceptions of objectives of Home Economics education showed a score of 3.46(SD = 0.80), which was slightly higher than the median. Second, the achievement perceptions of objectives of Home Economics education showed significant differences in gender, the grade level, school type, and the level of school records. Third, according to a hierarchical regression analysis, male students' middle school, coeducational middle school, grade, gender, and school record level had significant effects on their achievement perceptions of objectives of Home Economics education, and the explanatory power of these independent variables was 30%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.614-621
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• 2019

A generalized laminated composite beam element is presented for the flexural and buckling analysis of laminated composite beams with double and single symmetric cross-sections. Based on shear-deformable beam theory, the present beam model accounts for transverse shear and warping deformations, as well as all coupling terms caused by material anisotropy. The plane stress and plane strain assumptions were used along with the cross-sectional stiffness coefficients obtained from the analytical technique for different cross-sections. Two types of one-dimensional beam elements with seven degrees-of-freedom per node, including warping deformation, i.e., three-node and four-node elements, are proposed to predict the flexural behavior of symmetric or anti-symmetric laminated beams. To alleviate the shear-locking problem, a reduced integration scheme was employed in this study. The buckling load of laminated composite beams under axial compression was then calculated using the derived geometric block stiffness. To demonstrate the accuracy and efficiency of the proposed beam elements, the results based on three-node beam element were compared with those of other researchers and ABAQUS finite elements. The effects of coupling and shear deformation, support conditions, load forms, span-to-height ratio, lamination architecture on the flexural response, and buckling load of composite beams were investigated. The convergence of two different beam elements was also performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.643-651
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• 2020

A capsule train runs inside a sub-vacuum tube and can reach very high speed due to the low air resistance. A capsule train uses a superconducting electrodynamic suspension (SC-EDS) method for levitation, which allows for a large levitation gap and does not require gap control. However, SC-EDS has inherent characteristics such as the large gap variation and a small damping effect in the levitation force, which can degrade the running stability and ride comfort. To overcome this, a stability improvement device should be designed and applied based on dynamic analysis. In this study, a 1/10 small-scale testbed was developed to replicate the dynamic characteristics of a capsule train and investigate the performance of stability improvement devices. The testbed is composed of a 6-degree-of-freedom Stewart platform for the realization of bogie motion, a secondary suspension with a running stabilization device, and a carbody. Based on the dynamic similarity law proposed by Jaschinski, the small-scale testbed was manufactured, and a bogie motion algorithm was applied with the consideration of guideway irregularity and levitation stiffness. The experimental results from the testbed were compared with simulation results to investigate the performance of the testbed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.115-115
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• 2017

티타늄에 있어서 주요 침입형 원소인 산소는 결함을 일으키는 원인으로 산소함량을 줄이는 연구가 활발히 진행되고 있다. 최근 가장 많이 이용되는 탈산 방법은 칼슘 및 칼슘염화물의 높은 산소 친화력을 이용하는 것이다. 칼슘염화물 플럭스를 사용하여 칼슘을 용해하고, 티타늄과 반응한 탈산생성물인 칼슘산화물을 플럭스 내에 용해시키는 방법이다. 이러한 방법으로 티타늄 와이어 및 시트 내 산소를 저감한 연구가 보고되었다. 티타늄 탈산의 제일 큰 구동력은 티타늄 내 산소원자의 확산이다. 티타늄의 탈산온도가 1,155K 이상으로 증가하면 hcp에서 bcc 구조로 변태되는데 이러한 구조에서 산소의 확산은 더 활발해진다. 실제로 티타늄의 변태온도 이전에서는 확산속도가 낮아서 큰 변화가 없지만, 1,273K 고온의 bcc 구조에서는 확산속도가 빨라서 그 이전에 비해 100배 이상 빠르게 원자 이동이 일어나는 것으로 알려져 있다. 하지만 이러한 탈산 방법은 티타늄 원재료가 벌크 형태에서 주로 연구되었으며 티타늄 분말에 대한 탈산 연구는 보고된 바가 많지 않다. 이는 높은 탈산온도에서 칼슘의 용해로 인한 분말의 건전한 회수가 어렵기 때문이다. 이러한 문제를 해결하기 위해 본 연구진은 칼슘 증기를 이용한 비접촉식 탈산 용기를 제작하여 티타늄 분말을 변태온도 이상에서 탈산하여 1,000ppm 이하 저산소 티타늄 분말을 회수하였다. 칼슘을 이용한 티타늄 내 산소의 제거 메커니즘을 깁스자유에너지와 각각의 분압에 의해 설명하고 있다. 가장 일반적인 설명은 티타늄 내 산소가 탈산온도에 따라 확산하게 되며 이러한 산소는 티타늄의 표면에서 티타늄 산화층을 형성한다. 이때 탈산제인 칼슘의 높은 산소 친화력으로 티타늄 산화층은 분해되어 칼슘산화물을 형성한다. 이러한 과정으로 티타늄 내 산소가 제거되는 것으로 알려져 있다. 하지만 많은 탈산 연구에도 불구하고 대부분의 연구 보고에서는 탈산 전후의 산소 농도 변화만 측정하였으며, 실제적으로 티타늄 탈산 전후의 표면산화층의 변화, 티타늄 내부의 산소농도 변화 및 격자 변형에 대한 연구는 보고된 바 없다. 따라서 본 연구는 1,000 ppm 이하 저산소 티타늄 분말 제조에 있어서 탈산 전후 표면 산화층 및 내부 산소 농도 등을 분석하여 탈산 거동에 대해 관찰하였다. 본 연구에서 비접촉식 탈산용기를 이용하여 칼슘 증기에 의한 탈산에 의하여 1,000 ppm 이하 저산소 티타늄 분말 제조하였고, 탈산된 분말을 티타늄 원재료와 비교하여 표면 산화층, 격자 변형, 내부 산소 농도 등을 분석하여 탈산에 따른 산소 거동을 살펴보았다. 탈산된 티타늄 분말의 표면 산화층은 원재료 대비 73% 제거되어 약 3nm로 줄었음을 확인하였고, 또한 표면 산화층 감소뿐만 아니라 티타늄 분말 내부에서도 원재료보다 산소 농도가 감소하였음을 확인하였다.

• Composites Research
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• v.16 no.3
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• pp.25-31
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• 2003

In this work the effect of surface treated SiC on thermal stability and mechanical interfacial properties of carbon fiber/epoxy resin composites. The surface properties of the SiC were determined by acid/base values and contact angles. The thermal stabilities of carbon fiber/epoxy resin composites were investigated by TGA. The mechanical interfacial properties of the composites were studied in ILSS, critical stress intensity factor ($\textrm{K}_{IC}$), and critical strain energy release rate($\textrm{G}_{IC}$) measurements. As a result, the acidically treated SiC(A-SiC) had higher acid value than untreated SiC(V-SiC) or basically treated SiC(B-SiC). According to the contact angle measurements, it was observed that chemical treatments led to an increase of surface free energy of the SiC surfaces, mainly due to the increase of the specific(polar) component. The mechanical interfacial properties of the composites including ILSS, $\textrm{K}_{IC}$, and $\textrm{G}_{IC}$ had been improved in the specimens treated by chemical solutions. These results were explained that good wetting played an important role in improving the degree of adhesion at interfaces between SiC and epoxy resin matrix.

• Journal of Distribution Research
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• v.12 no.3
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• pp.1-21
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• 2007

This study introduces 'Free Market' that was recently developed in front of Hongik university. 'Free market', as a place for transactions for art products produced by artists or prospective artists, is held regularly every Saturday in front of Hongik university. This study collected data through in-depth interviews with participants and participant observations at the market to analyze the success factors of 'Free Market'. We described development process, unique characteristics of 'Free Market' and new experiential values that the market provide to the participants. This free market was introduced as roadside stand in the middle of 1990s when some artists started selling their works. It passed through the growth stage after it staged the event that had mixed characteristics of 'flee market' and 'art market' at local festivals in 2001. In 2002 Sin-Chon culture forum directedculture-oriented market and the market has been developed as a current 'Free Market'. Recently 'Free Market' is comprised of steps, artists, and customers who voluntarily participated in the market. The market is held regularly every Saturday and provide various types of programs for the participants. Major characteristics of this free market were summarized as 'complex space' and 'role transition', and these characteristics provided the participants new experiential values such as 'freedom', 'emergent experiences', 'social interaction' and 'hero of festivals' through the participant role. We interpret that 'Free Market' has been successfully settled down as a new type of retail store based on these new experiential values. Therefore, this case provides very useful implications that unique experiential values that a store provides to the customers can be major sources of store competitive advantages.

• Cartoon and Animation Studies
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• s.45
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• pp.283-298
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• 2016

Design is a fatal factor to differentiate and survive one product from the other in fierce competition of the market, when other conditions such as price or quality makes no much difference. Among many marketing tools, package design is known as a direct communication that visualizes and forms the very initial brand image of a product. Package design is not only for packing, transporting, storing and loading but for engraving the brand image in a consumers' mind and lead them to purchasing. One of recent package design trands is various ways of using character, not just as a printed image on the surface but as a part of three dimensional structure of package. If it succeed, the package design could give out the secondary fun and impact to the consumers. The package design with an effective character is itself a great marketing tool and valuable design asset, which can bring a further profit to the company. Especially, character-package can be a powerful and effective marketing method for various local products, in needs of further publication and sales with limited cost. It should motivate the sales of the products by grabbing their attention and taken as a souvenir. This research takes a character package as a useful marketing method for a local brand in Jeonju, South Korea, and tries to design a three dimensional package using its own character. Through the process, the research aims to propose an important design strategy for repositioning or enhancing an existing brand.

• Journal of Welding and Joining
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• v.15 no.6
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• pp.24-31
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• 1997

2매의 금속을 맞대어 그 한 쪽에 접촉면과 평행하게 고주파진동을 가하면 단 시간에 접합된다. 이공정을 초음파 용접이라고 하며 그 물리적인 본질은 아직 불분명 하지만, 첫째로는 강한 마찰에 의해 금속 자유면의 산화물층이 제거되기 때문이라는 점과 둘째로는 마찰에 의해 금속 표면이 강하게 가열되어 이에 따른 연화에 의해 접합 이 된다고 하는 점이다. 그러나 이와 같이 가열된다고 하더라도 가열은 표면부에만 국한되고 다른 부분은 가열되지 않는다. 따라서 초음파용접은 냉간접합이라고도 한다. 또 가압력과 진동에 의한 힘이 동시에 작용하기 때문에 용접할 면을 미리 청정하게 할 필요는 없고 용접전의 단계에서 자연적으로 청정화가 이루어진다고 하는 사실이 간접 적으로 증명되고 있다. 초음파 용접(Ultrasonic welding)의 특징을 요약하면 고상용접 의 일종으로서 용접중에 국부적으로 고주파 진동에너지와 압력을 가하여 용접하는 방법이다. 이 때 모재를 용융시키지 않고 건전한 야금학적 결합부가 얻어진다는 데에 큰 특징이 있다. 또한 초음파용접은 다른 용접법에 비해 경제성이 매우 높고, 초음파 용접에 필요한 출력이 전기아크 용접에 필요한 출력의 5 - 10%로 충분한 경우가 많다. 초음파 용접은 통상의 방법으로는 용접하기 어려운 동종 금속이나 이종 금속의 용접에 널리 사용된다. 이 용접법은 반도체, 미세회로, 전기 접점의 형성에 대한 생산기술 로서 사용되고 있는데 소형 모터, 알루미늄 박의 가공, 알루미늄 합금의 조립 등에 이용되고 있다. 한편 최근에는 자동차, 우주항공산업 분야의 구조제 용접용으로도 채용되고 있다.출함이 바람직하다.분비되는 배설-분비 항원의 자극과 깊은 관계가 있음을 알 수 있었다.넌트 명세서를 대한 XML DTD(Document Type Definition)를 정의하고, HTML 기반 검색 방법과 XML 기반 검색 방법에 대한 컴포넌트 검색 성능을 비교한다.따라 NO 생산 및 세포독성이 증가하였고. NO 생산을 저하시키는 약제들은 활성화된 복강 대식세포 및 RAW264.7 세포에 의한 질편모충에 대한 세포독성을 현저히 감소시키는 것으로 보아 NO는 질편모충에 대한 대식세포의 숙주 방어기전에서 중요한 역할을 감당할 것으로 생각된다.nction index) 와 최대개구시 동통의 정도는 시술전과 시술 4주후간에 유의한 차이가 관찰되었다.피부온도는 검사자간에는 특정부위에 따라 다소 차이가 있을 수 있으나 일반적으로 높은 재현성을 보여줌으로서 향후 교근 및 측두근의 임상연구 평가에 피부온도조사는 도움이 되리라 사료된다. lactobacilli의 양은 peroxidase system을 함유하거나(p < 0.01) 함유하지 않은(p < 0.05) 치약을 사용한 군 모두에서 양치전에 비해 유의성있게 감소하였다. 6. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 S. mutans 양은 peroxida system을 함유한 세치제를 사용한 군에서 대조군에 비해 유의성있게 낮았다(p < 0.05). 7. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 lactobacilli양은 peroxidase system을 함유한 세치제를 사용한 군에서 대조군에 비해 상대적으로 낮게 나타났으나(p = 0.067)