• Advances in nano research
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• 제16권3호
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• pp.231-249
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• 2024

When the amplitude of the vibrations is equivalent to that clearance, the vibrations for small amplitudes will really be significantly nonlinear. Nonlinearities will not be significant for amplitudes that are rather modest. Finally, nonlinearities will become crucial once again for big amplitudes. Therefore, the concrete panel system may experience a big amplitude in this work as a result of the high temperature. Based on the 3D modeling of the shell theory, the current work shows the influences of the von Kármán strain-displacement kinematic nonlinearity on the constitutive laws of the structure. The system's governing Equations in the nonlinear form are solved using Kronecker and Hadamard products, the discretization of Equations on the space domain, and Duffing-type Equations. Thermo-elasticity Equations. are used to represent the system's temperature. The harmonic solution technique for the displacement domain and the multiple-scale approach for the time domain are both covered in the section on solution procedures for solving nonlinear Equations. An effective data-driven solution is often utilized to predict how different systems would behave. The number of hidden layers and the learning rate are two hyperparameters for the network that are often chosen manually when required. Additionally, the data-driven method is offered for addressing the nonlinear vibration issue in order to reduce the computing cost of the current study. The conclusions of the present study may be validated by contrasting them with those of data-driven solutions and other published articles. The findings show that certain physical and geometrical characteristics have a significant effect on the existing concrete panel structure's susceptibility to temperature change and GPL weight fraction. For building construction industries, several useful recommendations for improving the thermo-mechanics' behavior of structural concrete panels are presented.

• 한국안전학회지
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• 제19권4호
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• pp.109-116
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• 2004

The dynamic behavior of the rectangular liquid storage structure is known to be greatly influenced by fluid-structure interaction. By mounting the liquid storage structure on the properly designed base isolators, dynamic response of the superstructure can be reduced. However, base isolators inevitably incur large displacement of the structure to the ground ·ind may give adverse effects on the sloshing height. This paper presents the analysis method for fluid-structure-isolator interaction in base-isolated rectangular liquid storage structures. In the method, the irrotational motion of invicid and incompressible ideal fluid is expressed by analytic solutions and the superstructure and isolators are properly modeled by finite element and bilinear model. Free surface sloshing motion, hydrodynamic pressure acting on the wall and structural response are obtained by the presented method.

• 한국응용과학기술학회지
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• 제28권3호
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• pp.306-312
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• 2011

In this study, we are crystallized to the low density polyethylene (LDPE) micro-particles in $n$-dodecanol solution by thermally induced phase separation(TIPS) method. The Low density polyethylene micro-particles is used in a wide variety of polymer coatings and industrial application. The utility of that for a particular application depends on a number of factors such as the particle size and distribution, and chemical composition of the materials. However, there are still needs for new methods of preparation which will provide the structure with unique sizes. The widely used processes for micro-size particles are crystallization method and thermally induced phase separation. TIPS process based on the phase separation mechanism was performed for the LDPE system which undergoes liquid-solid phase separation. Effects of various operating parameters were examined on the structure variation of the particles. Professionality, take-up speed and crystallization rate depended on temperature and concentration of polymer in solution.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.245-250
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• 2006

This study was focused on the use of cationic PAM (Polyacrylamide) as a surface sizing additive to improve the surface sizing properties of paper. Effects of the ionic property, viscosity and charge density of PAM on bending stiffness of surface sized papers were investigated. Use of cationic PAM as a surface sizing additive improved bending stiffness while addition of anionic PAM did not show any effect. Increase of starch holdout with the addition of cationic PAM was attributed as a prime reason of stiffness increase. Viscosity of PAM was one of the most important factors affecting surface sizing due to its influence on the interaction between cationic PAM and oxidized starch solution. Greater improvement of bending stiffness of paper was obtained when high charged PAM was used as an additive. The order of addition was found to have significant influence on the effect of additives since it influences the formation of network structure among starch, cationic PAM, and SA (styrene acrylic acid copolymer). Investigation on the penetration of starch solution was carried out with CLSM (Confocal Laser Scanning Microscopy), and it was shown that the addition of cationic PAM to oxidized starch solution made starch molecules stay on the paper surface rather than penetrating into the paper structure because of the electrostatic interaction between negatively charged fibers and positively charged cationic PAM.

• 한국측량학회지
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• 제13권1호
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• pp.31-39
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• 1995

각종 구조물의 노후화에 따른 안전 진단 방법의 일환으로 각종 측정이 이루어지고 있으나 이들 구조물의 변형량 측정방법에 있어서 정확도와 신뢰성 및 가시성의 문제가 노출되고 있어 이의 해결 방법의 마련이 절실히 요구되고 있는 실정이다. 따라서 본 연구에서는 이에 부합되는 시스템의 마련을 위하여 근거리 사진 측량 방법을 적용해 봄으로서 구조물의 변형 측정 정확도와 신뢰성 및 가시성을 확보할 수 있는 시스템을 마련하고자 한다. 그의 일환으로 수평 직각 촬영 방법과 경사 촬영 방법으로 구조물의 형태의 대표적 모형 인 평면, 곡면 모델을 제작하여 적용해석 함으로서 촬영 방법에 따른 정화도 향상 및 가시성등을 높이는 최적의 시스템을 구축하였고, 그에 따른 실제 구조물의 변형량측정에 이용될 수 있도록 하였다.

• 한국자기학회지
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• 제8권5호
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• pp.295-299
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• 1998

페라이트 도금 방법은 진공이 불필요하며 저온(<10$0^{\circ}C$)에서 페라이트 박막을 제작할 수 있다. 이 방법으로 기판온도 8$0^{\circ}C$, 산화용액의 pH 7.1~8.8 영역에서 모두 스피넬 구조의 NixFe3-xO4 (x=0.162~0.138) 박막을 얻었다. 이들은 열처리를 하지 않았음에도 불구하고 결정성이 우수한 다결정의 박막을 얻었다. 박막의 성장속도는 산화용액의 pH가 7.1에서 8.8까지 변함에 따라 성장속도가 143$\AA$/min에서 255 $\AA$/min 까지 증가하였다. 산화용액의 pH가 증가할수록 입경의 크기가 증가하고, 보자력은 감소하였다.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.645-650
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• 1997

We manufactured CoNbZr/Cu/CoNbZr multi-layer films by rf magnetron sputtering methods and formed the patterns on the deposited multi-layer films. In this study, we fabricated a new etchant for forming the patterns by the wet etching with etchant and we searched for the best etching conditions and the etchant composition. Cu was etched selectively independent on the concentration of iron chloride solution, but amorphous CoNbZr thin film did not. The etchant was achieved by iron chloride solution(17.5 mol%) mixed with HF (20 mol%) during 150 sec, which etched CoNbZr/Cu/CoNbZr multi-layer films at the same time. Also, the etchant etched CoNbZr/Cu/CoNbZr multi-layer films by the three-step. It was shown that the cross-section had the isotropic structure and excellent etching characteristics with the above etchant.

• 한국분말재료학회지
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• 제17권6호
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• pp.449-455
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• 2010

The hybrid structured photo-electrode for dye-sensitized solar cells was fabricated based on the composites of $TiO_2$ nanoparticles and nanowires. Three samples with different hybrid structures were prepared with 17 vol%, 43 vol%, and 100 vol% nanowires. The energy conversion efficiency was enhanced from 5.54% for pure nanoparticle cells to 6.01% for the hybrid structure with 17 vol% nanowires. For the hybrid structured layers with high nanowires concentration (43 vol% and 100 vol%), the efficiency decreased with the nanowire concentration, because of the decrease of specific surface area, and of thus decreased current density. The random orientations of $TiO_2$ nanowires can be preserved by the doctor blade process, resulted in the enhanced efficiency. The hybrid structured $TiO_2$ layer can possess the advantages of the high surface area of nanoparticles and the rapid electron transport rate and the light scattering effect of nanowires.

• 한국주조공학회지
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• 제7권2호
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• pp.108-113
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• 1987

Al-Cr alloy with composition in the range from 1.5 wt% to 10 wt% Cr were rapidly solidified from the melt by the single roller method. The supersaturated solid solution was obtained up to 6 wt% Cr in Al-Cr alloy for $20{\mu}m$ thickness. Lattice parameter decreased with increasing Cr content at the rate of 0.00456A per wt% Cr up to 6 wt% Cr. Microhardness increased with increasing Cr content at the rate of $10\;Kg/mm^2$ per wt% Cr up to 6 wt% Cr. Microhardness measurements on the Al-6 wt% Cr supersaturated solid solution annealed isothermally showed no sign of age hardening. Decomposition temperature, determined by lattice parameter changes and microhardness changes, was $470^{\circ}C$ for Al-6 wt% Cr supersaturated solid solution. Transmission electron microscopy showed that decomposition within one hour below $400^{\circ}C$ occurred at grain boundaries only, and also the additional decomposition within grains being evident at $450^{\circ}C$ The coarse precipitate structure showed at $500^{\circ}C$ and $550^{\circ}C$, respectively. The coarse precipitate structure is considered $Al_7Cr$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.290-291
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• 2006

The effect of praseodymium substitution on the ferroelectric properties of $Bi_4Ti_3O_{12}$ thin films have been investigated. Ferroelectric Pr-substituted $Bi_4Ti_3O_{12}$ thin films were fabricated by chemical solution deposition onto Pt/Ti/$SiO_2$/Si substrates. The structure and morphology of the films were analyzed using Xray diffraction, and scanning electron microscopy, respectively. About 200-nm-thick BPT films grown at $720^{\circ}C$ exhibited a polycrystalline structure and showed excellent ferroelectric properties with a remanent polarization ($2P_r$) of $28.21\;{\mu}C/cm^2$ at an applied voltage of 5 V. The films a1so demonstrate fatigue-free behavior up to $10^{11}$ read/write switching cycles with 1 MHz bipolar pulses at an electric field of ${\pm}5\;V$.