• Composites Research
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• 제20권6호
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• pp.15-20
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• 2007

본 연구에서는 혼합 보 이론을 이용하여 초기 비틀림 각을 갖는 박벽 복합재료 보에 대한 정적 거동 해석을 수행하였다. 보 해석 모델은 복합재료의 연계특성 및 박벽 두께효과, 그리고 비틀림 워핑을 고려하고 있다. 보의 인장-굽힘-비틀림 정적 거동에 대한 혼합적인 요소를 효과적으로 고려함과 동시에 보의 이론 전개를 위해 Reissner의 반보족에너지 함수를 도입하였다. 초기 비틀림 각의 도입에 따른 굽힘 및 비틀림 관련 워핑함수를 특별한 가설에 의존하지 않고 엄밀하게 유도하였다. 개발된 보 이론의 신뢰성을 제고하기 위한 일환으로 탄성적으로 연계된 복합재료 보에 대해 정적 구조해석을 수행하였으며, 해석 결과를 기존의 이론 및 유한요소 해석결과와 비교하여 그 타당성을 확보하였다.

• Advances in concrete construction
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• 제13권 2호
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• pp.153-162
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• 2022

Prefabricated exterior wall panel is the main non-load-bearing component of assembly building, which affects the comprehensive performance of thermal insulation and durability of the building. It is of great significance to develop new prefabricated exterior wall panel with durable and lightweight characteristics for the development of energy-saving and assembly building. In the prefabricated sandwich insulation hanging wall panel, the selection of material for the outer layer and the arrangement of the connector of the inner and outer wall layers affect the mechanical performance and durability of the wall panels. In this paper, high performance cement-based composites (HPFRC) are used in the outer layer of the new type wall panel. FRP bars are used as the interface connector. Through experiments and analysis, the influence of the arrangement of connectors on the mechanical behaviors of thin-walled composite wall panel and the panel with window openings under two working conditions are investigated. The failure modes and the role of connectors of thin-walled composite wallboard are analyzed. The influence of the thickness of the wall layer and their combination on the strain growth of the control section, the initial crack resistance, the ultimate bearing capacity and the deformation of the wall panels are analyzed. The research work provides a technical reference for the engineering design of the light-weight thin-walled and durable composite sandwich wall panel.

• Steel and Composite Structures
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• 제50권2호
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• pp.159-181
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• 2024

In the present study, the effect of geometrical parameters of two different types of aluminum thin-walled structures on energy absorption under three-bending impact loading has been investigated experimentally and numerically. To evaluate the effect of parameters on the specific energy absorption (SEA), initial peak crushing force (IPCF), and the maximum crushing distance (δ), a design of experiment technique (DOE) with response surface method (RSM) was applied. Four different thin-walled structures have been tested under the low-velocity impact, and then they have simulated by ABAQUS software. An acceptable consistency between the numerical and experimental results was obtained. In this study, statistical analysis has been performed on various parameters of three different types of tubes. In the first and the second statistical analysis, the dimensional parameters of the cross-section, the number of holes, and the dimensional parameter of holes were considered as the design variables. The diameter reduction rate and the number of sections with different diameters are related to the third statistical analysis. All design points of the statistical method have been simulated by the finite element package, ABAQUS/Explicit. The final result shows that the height and thickness of tubes were more effective than other geometrical parameters, and despite the fact that the deformations of the cylindrical tubes were around forty percent greater than the rectangular tubes, the top desirability was relevant to the cylindrical tubes with reduced cross-sections.

• 한국안광학회지
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• 제13권1호
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• pp.59-63
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• 2008

목적: 소형 magnetron sputtering 장치를 이용하여 CR-39 안경렌즈와 glass위에 코팅한 썬글라스 렌즈용 Ti박막의 광학적 특성에 관한 연구이다. 방법: SEM 단면 사진으로 Ti 코팅 박막의 두께를 측정하였고, spectrophotometer를 이용하여 Ti 박막의 투과율과 반사율을 측정하였다. Variable angle spectroscopic ellipsometry (VASE)를 이용하여 파장에 따라 Ti 박막의 굴절률과 소멸계수를 구하였다. 결과: 두께가 60 nm, 120 nm, 140 nm인 시료에 대한 투과율은 가시광선 영역인 파장 400 nm에서 750 nm까지 변화가 크지 않았으며 모두 silver tone에 가까운 color를 보였다. 가까운 파장 400 nm 근처에서 약간 올라가는 경향을 보였고, He d선 (587.6 nm)을 기준으로 할 때 Ti 박막의 두께가 60 nm에서 투과율이 33%, 두께가 120 nm에서 투과율이 25%, 두께가 140 nm에서 투과율이 20%를 보였다. 결론: Ti 박막의 경우 60~140 nm의 모든 두께에서 선글라스용으로 적합한 것을 알 수 있었다. Ti박막에 대한 굴절률이 작게 나오는 것은 Ti박막의 두께가 얇기 때문이라고 여겨진다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 봄 학술발표회 논문집
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• pp.111-115
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• 1998

Fiber spinning is a continuous deformation process by which material is converted into a fiber. The melt spinning process was analyzed mainly by employing an asymptotic method of the so-called thin filament equations which formulates dynamics of spinning process by averaging over the cross-section of filament the set of fundamental equations. The method gives the approximate results for commonly used circular fiber spinning.(omitted)

• Applied Microscopy
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• 제21권1호
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• pp.77-85
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• 1991

The virus maturation in fat body cells infected with P. rapae granulosis virus were also examined to have the following results. Thin section of P. rapae GV granules showed a regular lattice of the granule enclosing virus particles. Virus particles were observed to penetrate the fat body cells by fusion or viropexis type. The blood and fat body cells uptaked the granulosis viruses a phagosome, in which they were digested by lysosomal enzymes.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.5-8
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• 2000

This paper presents the analytical investigation pertaining to the local buckling behavior of orthotropic open section thin-walled compression members with asymmetric edge stiffeners. In the analysis, 3 different cases of the second moment of inertia are considered to find the asymmetric edge stiffener effect on the local buckling strength. The analytical study results are presented in the graphical form so that the edge stiffener effects on the local buckling strength can be easily found.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.533-539
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• 2001

In this research, design Sensitivity Analysis is presented for commercial vehicle such as large scale structural system. The proposed method is based on vibration analysis of the total structure and design sensitivity to identify the contribution factor of the component structure to the total system structure. In addition, approximated equations derived from response surface method are used for representative section properties of the thin walled beams.

• 소성∙가공
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• 제5권2호
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• pp.165-175
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• 1996

the process of strip twisting is practiced for the manufacture of some commercial parts such as elements for tube type line mixers. A thin metal strip with rectangular cross section is twisted thru an angle greater than 180。. Initial geometry is altered in to a complex one with dimen-sional changes. In practice several tryouts are necessary to obtain required dimensional accu-racies. A simple analysis model is proposed to predict the dimensional changes forming torque and axial force.

• 한국결정성장학회지
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• 제10권2호
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• pp.111-115
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• 2000

Ba과 Ti의 금속 유기 화합물을 이용하여 (100) $SrTiO_3$ 기판 위에 $BaTIO_3$ 박막을 코팅-열분해법으로 제조하였다. $450^{\circ}C$에서 사전 열처리한 비정질상의 박막은 $2\times 10^{-4}$ atm으로 조정된 산소 분압 하에서 $700^{\circ}C$ 이상의 온도로 열처리함으로써 결정화되었다. $800^{\circ}C$ 이하에서 제조한 박막의 기판에 수직한 면의 격자상수는 cubic $BaTIO_3$의 a 값에 가까우면 $800^{\circ}C$ 이하에서 제조한 박막의 tetragonal $BaTIO_3$ 의 a 값에 가까 웠다. 박막과 기판의 정렬상태를 XRD $\beta$ scan과 pole-figure로 분석한 결과 $BaTIO_3$ 박막은 $SrTiO_3$ 기판과 에피택시 관계가 있었다. $800^{\circ}C$에서 열처리한 박막의 표면은 0.4${\mu}m$ 정도의 섬 형태의 입자로 구성되어 있었고 약 0.8$\mu\textrm{m}$의 두께를 가진 단면은 구형의 입자가 층을 이루고 있었다.