• Journal of the Korean Wood Science and Technology
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• 제43권1호
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• pp.36-42
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• 2015

국산재에 대한 전단탄성계수와 실질탄성계수를 구하기 위해 서로 다른 세장비에 대한 휨강도실험 및 응력파실험을 실시했다. 국산재의 휨 성질들은 12%로 조습 처리된 무결점 시편으로 측정하였다. 휨강도와 탄성계수는 세장비(L/D)에 영향을 받아 세장비가 증가하면 증가하였다. 전단탄성계수(G)와 실질탄성계수는 서로 다른 세장비에 대한 휨강도 실험 및 응력파실험의 결과를 이용하여 계산했고, 그 값들은 국산재가 구조용도로 사용된다면 유용할 것이다. 하지만 이들 결과들은 제한된 수의 시편들에 대한 값으로 이들 수종의 실질 평균값을 나타내진 않는다.

• 콘크리트학회논문집
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• 제17권6호
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• pp.1033-1042
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• 2005

최근에 이르기까지 철근콘크리트 휨부재에 있어 콘크리트의 인장응력은 극한강도에 현저한 영향을 미치지 못하기 때문에 그 역할이 고려되어지지 않았다. 그러나 하중-처짐 관계의 구명을 위해서는, 인장증강효과라고 불리는 콘크리트와 보강철근 사이의 인장응력에 의한 강정증가 효과가 반드시 고려되어져야 한다. 이러한 인장증강효과에 영향을 주는 주요 구조변수는 콘크리트의 강도 및 콘크리트와 철근의 부착 등으로 알려져 있다. 이 연구에서는 휨을 받는 보를 대상으론 각기 다른 콘크리트 강도, 피복두께 및 주근의 비부착 길이를 갖도록 모두 20개의 시험체를 제작하여 실험하였다. 이를 통해 각 구조변수들이 시험체의 휨강성, 균열발생 및 진전 등에 미치는 영향 등을 주의 깊게 관찰하고 분석하였다.

• Korea Journal of Cosmetic Science
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• 제2권1호
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• pp.1-10
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• 2020

Protection mechanisms for skin damage of ultraviolet (UV) absorbers in personal care products for protection against UV are well studied, but not for hair protection. The purpose of this study is to describe and compare the changes of physical property produced in human hair by doses of the UV-B exposure causing protein degradation. To observe the change of physical properties in hair, the experimental intensity of UV-B exposure has been established on the basis of statistical data from official meterological administration as daily one hour sunlight exposure for two weeks. Polysilicone-15, ethylhexyl methoxycinnamate (OMC), and octocrylene were employed for UV-B absorber, and those were treated to hair swatch by rubbing wash through shampoo and conditioner. Bending rigidity displayed kinetically successive reduction at high doses of UV exposure up to the 8,000 s, and exhibited different level at each sample of UV-B absorber. However, the values of Bossa Nova Technologies (BNT) for shinning factor were already saturable at the 2,000 s exposure except that treated with polysilicone-15. The differential scanning calorimetry (DSC) to measure a strength of inner protein produces a successive reduction of enthalpy as like a reduction of bending rigidity upon UV exposure. Surface roughness from lateral force microscope (LFM) acquired immediately after UV exposure show a saturable frictional voltage which has been also found in a saturable BNT data as the time of UV exposure increases. Through researching the DSC and the LFM, shinning of hair was much correlated to the protein damage at the surface, and bending rigidity could be regulated by the protein structural damage inside hair. Therefore, the optimization of efficient strategy for simultaneous prevention of hair protein on the surface and internal hair was required to maintain physical properties against UV.

• 동력기계공학회지
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• 제17권1호
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• pp.97-103
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• 2013

Press machine has advantages over other manufacturing machine which can produce large quantities of products in short time so it is widely used in lots of industrial sectors. To obtain the vehicle's weight lightening and rigidity of the body-frame by applying 'Hot stamping' technique is increasing in the automotive field. In this paper, to improve the irregular vibration arose by 800Ton hot stamping press, the research was continued. Bed, slide and main frame are the key part of working precision, so perform structural analysis was conducted, and based on the analyzing results, structural changes were done on the parts where structural deformation occurred.

• 한국기계가공학회지
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• 제13권2호
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• pp.117-123
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• 2014

In order to provide a mobile robot with omnidirectionality, various types of omnidirectional wheels have been developed. This paper deals with an improved design and structural analysis of a Mecanum wheel, which is the type of omnidirectional wheels most commonly used in industrial fields. A geometric formulation for manufacturingthe Mecanum wheel is presented and two types of Mecanum wheels are designed and fabricated in this research. While conventional assembled-type Mecanum wheels have a complicated structure and the high possibility of mutual interference between sub-components, a unified type of Mecanum wheel reduces the number of sub-components and increases the degree of structural rigidity. The stress and strain properties of the two designs are compared to confirm the quantitative improvement of the new design by a commercial structural analysis tool. The analysis results show that the unified type of Mecanum wheel has properties superior to the assembled type of Mecanum wheel in terms of its ability to reduce interference.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.93-100
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• 1998

The basic systems of spatial structures such as shells, membrane, cable-nets and tensegrity structure have been developed to create the large spaces without column. These structures may have large freedom in scale and form, and especially tensegrity structures are received much attention from the view points of their light weight and aesthetics. But There re some difficulties concerning structural stability, surface formation and construction method. One of the way to solve these problems reasonably is a combination of tensile members and rigid members. A structural system based on this concept is referred to as the "HTS ( Hybrid Tension Structure )". This is a type of flexible structural system which is unstable initially, because the cable material has little initial rigidity. As cable - dome hybrid structures is a type of HTS, the initial stress for the self- equilibrated system having stable state have to be introduced. To determine initial stress having stable state, the shape finding analysis is required before the stress - deformation analysis. In this paper, the primary objective is to derive the nonlinear finite element formula of cable and truss members considering geometric nonlinearity for shape finding of cable-dome, and to propose the method to decide the initial stress by the shape analysis of cable-dome hybrid structure with the self-equilibrated state.

• 교육시설 논문지
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• 제26권5호
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• pp.25-36
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• 2019

School gymnasium is a multi-purpose large space building for various events and physical education activities, and is a facility that requires an approach to the desirable structural design, besides mechanical problems of structure against loads. For the integrated structure design concerning the architectural features, the major considerations of gymnasium planning that are the internal and external shape of the gymnasium, the space scale with structure members, the structural efficiency by members weight reduction and openness of the gymnasium space will have to take into account in the structural planning. From this point of view, the several cases of the school gymnasium were investigated and the parametric analyses were performed to the models using the various structural system. The parameters were the composition elements of structure system that are profile of structure, rigidity of member, connection and anchorage and stability. At the result, It was presented that the profile of structure member was the most influential factor to structural efficiency and the effect of the form and space of gymnasium. Also the design informations of structure design having the various feature of form and space were presented for the initial gymnasium planning.

• 대한조선학회논문집
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• 제59권1호
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• pp.29-38
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• 2022

In offshore installations, fires cause the structure to lose its rigidity and it leads to structural integrity and stability problems. The Passive Fire Protection (PFP) system slows the transfer rate of fire heat and helps prevent the collapse of structures and fatality. Especially, intumescent epoxy coating is widely used in the offshore industry, and not only is the material cost expensive, but it also takes a lot of time and cost for construction. Several studies have been conducted on the efficient application and optimal design of the PFP system. However, the mechanical properties and the strength of the PFP material have not been considered. In addition, researches on the correlation between the thickness of PFP and the structural behavior were insufficient. Therefore, this study aims to analyze the thermal and mechanical effects of the PFP on the structure when it is applied to the structural member. In particular, it is intended to resolve the change in strength characteristics of the structural members as the thickness of the PFP increases.

• 콘크리트학회지
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• 제11권2호
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• pp.105-113
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• 1999

본 연구의 목적은 아라미드 섬유쉬트로 보강된 상판의 보강효과를 구명하는데 있다. 단면 칫수가 $45{\times}200{\times}8.5cm$인 7개의 콘크리트 슬래브를 제작하여, 이중 한개의 슬래브는 최대하중을 알아보기 위하여 무보강 상태로 파괴될 때 까지 하중을 가하였다. 또한 3개의 슬래브는 최대하중의 70%를 가여 균열을 발생시킨 후 아라미드섬유 쉬트로 보강하였고, 나머지 3개의 슬래브는 균열을 발생시키지 않고 직접 아라미드섬유 쉬트로 보강하였다. 연구결과 최대하중, 휨강도 및 연성효과는 초기균열을 갖는 보강된 슬래브와 초기균열이 없는 상태에서 보강된 슬래브가 비슷한 양상을 나타냄으로써 아리미드 섬유쉬트에 의한 슬래브의 보강효과를 확인 할 수 있었다.

• 한국의류학회지
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• 제25권3호
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• pp.650-661
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• 2001

The purpose of this study is to suggest a guidance to select proper muslin through investigating fabric characteristics. The structural and physical properties of muslin and top fabric samples were tested by KES-FB system and other testers. And in order to examine the relation between fabric characteristics and the shape of garments, wearing tests were done with jackets made of those samples. As a result, bending rigidity(B), bending hysteresis(2HB), shear stiffness(G), shear hysteresis at=0.5(2HG), shear hysteresis at=5(2HG5), stiffness, cloth count/5cm, weight, thickness were extracted as the key factors affecting the appearance of garments. To have similar appearance, all of these should be counted. After standardizing, we calculate the variance between top cloth and muslin. And from this we could get the range that the proper muslin should be included. The ranges were as follows: Bending rigidity(B): within 0.024g.$\textrm{cm}^2$/cm(0.3$\sigma$); Shear stiffness(G): within 2.21g/cm.degree(1.3$\sigma$) Weight: within 9.33mg/$\textrm{cm}^2$(18$\sigma$); Thickness: within 0.20mm(1.8$\sigma$)