• Macromolecular Research
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• 제16권5호
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• pp.424-428
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• 2008

We prepared an ionic gel polymer electrolyte for dye-sensitized solar cells (DSSCs) without leakage problem. Triiodide compound (BTDI) was synthesized by the reaction of benzene tricarbonyl trichloride with diethylene glycol monotosylate and subsequent substitution of tosylate by iodide using NaI. Bisimidazole was prepared by the reaction of imidazole with the triethylene glycol ditosylate under strongly basic condition provided by NaH. BTDI and bisimidazole dissolved in an ionic liquid were injected into the cells and permeated into the $TiO_2$ nanopores. In situ crosslinking was then carried out by heating to form a network structure of poly(imidazolium iodide), thereby converting the ionic liquid electrolytes to a gel or a quasi-solid state. A monomer (BTDI and bisimidazole) concentration in the electrolytes of as low as 30 wt% was sufficient to form a stable gel type electrolyte. The DSSCs based on the gel polymer electrolytes showed a power conversion efficiency of as high as 1.15% with a short circuit current density of $5.69\;mAcm^{-2}$, an open circuit voltage of 0.525 V, and a fill factor of 0.43.

• 한국세라믹학회지
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• 제43권11호
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• pp.724-727
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• 2006

It has long been known that the oxidation kinetics of Zr-based alloys undergoes a crossover from parabolic to cubic in the pretransition period (before breakaway of the oxide scale). This kinetic crossover, however, is not fully understood yet. We have earlier proposed a model for the Zr-oxidation kinetics, in a closed form for the first time, by taking into account a compressive strain energy gradient as a diffusional driving force in addition to a chemical potential gradient of component oxygen across the ZrO$_2$ scale upon Zr [J. Nucl. Mater., 299 (2001) 235]. In this paper, we experimentally reconfirm the validity of the proposed model by using the thermogravimetric data on mass gain of Zr in a plate and wire form, respectively, in air atmosphere at different temperatures in the range of 500$^{\circ}$ to 800$^{\circ}C$, and subsequently report on the numerical values for oxygen chemical diffusivity and strain energy gradient across the oxide scale.

• Journal of Pharmaceutical Investigation
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• 제27권3호
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• pp.219-223
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• 1997

Terfenadine, antihistaminic drug, is poorly soluble in water. The purpose of this study is to investigate the possibility of using $terfenadine-{\beta}-cyclodextrin$ inclusion compound, instead of terfenadine, as the active substance of solid dosage form by improving the solubility, dissolution and anti-histaminic activity of terfenadine. The solubility and binding characteristics of $terfenadine-{\beta}-cyclodextrin$ complex in pH $1.2{\sim}6.8$ were investigated. Furthermore, the preparing method of $terfenadine-{\beta}-\;cyclodextrin$ inclusion compound was setting up and its physico-chemical characteristics such as DSC curve, solubility, dissolution and anti-histaminic activity were investigated. In conclusion, the solubility of terfenadine was increasing ${\beta}-cyclodextrin$ and with the decreasing pH. $Terfenadine-{\beta}-cyclodextrin$ inclusion compound, whose yield is almost 100%, was prepared by neutralization method. This inclusion compound was 200-times as soluble as terfenadine in pH 1.2-6.8. In addition, it had the faster dissolution and anti-histaminic activity than terfenadine. Therefore, it is used to the active substance of solid dosage form such as tablet and capsule in stead of terfenadine.

• 한국항공우주학회지
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• 제49권10호
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• pp.813-820
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• 2021

본 연구에서는 고체추진제의 동적 응력-변형률 특성을 고찰하기 위하여 저속충격시험을 수행하였다. 저속충격시험 시 충격체(Impactor)의 하중, 변위를 측정하여 고체추진제의 동적 거동을 확인하였다. 3점 굽힘 형태의 저속충격시험을 수행하였고, 이때 발생하는 국소변위와 길이가 짧고 두께가 두꺼운 고체추진제 시편의 전단 변위를 보상하여 순수 굽힘변위를 계산하였다. 보상된 변위와 측정된 하중을 사용하여 응력과 변형률을 계산하였고 응력-변형률 곡선으로부터 고체추진제의 동적 물성을 획득하여 이를 정적 굽힘 물성과 비교하였다. 운용 환경에 따른 온도별 고체추진제의 동적 물성을 획득하기 위해 상온, 고온, 저온에서 실험을 수행하고 결과를 비교분석하였다.

• 소음진동
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• 제7권3호
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• pp.449-455
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• 1997

A theoretical study is presented for the prediction of the scattering of obliquely incident plane acoustic wave by transversely isotropic cylindrical shells immersed in water. In dorder to illustrate the vailidity of the theory backscattering form functions are compared with the existing results for degenerated problems: the catterings by isotropic shell and transversely isotropic solid cylinder. The unidirectional fiber reinforced boron-aluminum composites are selected as a model of transversely isotropic materials having potential applications in practice. From the resonant scattering analysis of the partial backscattering form functions, the dispersion curves for fluid-borne Stoneley wave, guided wave along the shell, and the lowest three Lamb type waves can be found. The Lamb type dispersions are compared with those of the flat plate. The variation of anisotropy significantly affects the properties of circumferential waves. From these results, it can be possible to identify parametrically the material properties of anisotropic cylindrical targets.

• Animal Systematics, Evolution and Diversity
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• 제23권2호
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• pp.169-173
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• 2007

Two new marine sponges in the family Chalinidae, Haliclona (Haliclona) uljinensis n. sp. and Haliclona (Reniera) hongdoensis n. sp., are collected from Uljin and Hongdo Island, Korea during 2004-2007. H. (H.) uljinensis n. sp. is closely related to H. (H.) oculata in type of spicules. However, ectosomal skeleton of H. (H.) uljinensis n. sp. is reticulated and isodictyal reticulated type but H. (H.) oculata has not any dermal specialization in skeleton. The growth form of H. (H.) uljinensis n. sp. is thin encrusting with numerous cylindrical tubes on the surface but H. (H.) oculata is solid branch form. Haliclona (R.) hongdoensis n. sp. is closely related to H. (R.) aquaeductus in skeletal structure and growth form. However, oxeas of H. (R.) hongdoensis n. sp. are larger than H. (R.) aquaeductus's.

• 한국의류학회지
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• 제29권12호
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• pp.1582-1594
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• 2005

이 연구의 목적은 패션디자인에서의 형태의 중요성을 이해하는 새로운 시각을 제시하는데 있다. 뵐플린과 드롱의 이론을 바탕으로 Flat St Rounded, Closed & Opened 과 Part & Whole의 세 가지 형태를 보는 시각을 가지고 Vionnet와 Dior 작품에서의 형태미를 분석하는데 적용시켜 고찰해 보았다. Vonnet와 Dior은 그들의 디자인에서 형태와 구조를 디자인의 기본원리로 하여 기하학적인 형태를 그들의 디자인에 적용시킨 디자이너들이다. Vionnet의 10작품과 Dior의 11작품을 선정해 Belong의 visual priorities diagram을 적용시켜 각 디자이너 작품의 형태미를 고찰하고 비교해 보았다. Vionnet는 의복과 인간의 신체 사이의 관계를 통해 새로운 형태미학을 창조해 냈으며 그녀의 작품은 2차원 또는 3차원이라는 공간의 차이에 따라 형태의 전위를 보여주는 독특한 형태학적 특성을 보여주고 있다 그녀의 작품은 2차원의 공간에서는 평면적이고 닫힌 형태인 삼각형, 사각형, 원으로 구성되어 있으나 바이어스 재단에 의한 입체재단 방법을 통해 3차원의 공간에서는 입체적이고 열린 형태로의 형태변형을 한다는 특징을 나타낸다. Dior의 작품은 인체의 자연스러운 형태보다는 인위적인 형태미를 보여주고 있으며 이는 Vionnet작품과의 커다란 차이점이다. Dior은 3차원의 공간에서 구, 각기둥, 원기둥, 각뿔, 입방체와 같은 입체 기하학의 형태를 사용하여 의복의 형태를 만들어 냈고 이는 다아트 변형, 보닝, 개더, 턱, 플리츠, 셔링과 같은 구조주의적인 기술을 통해 실현되고 있다. Dior의 작품은 3차원의 공간에서 인체의 형태와는 무관한 의복 자체만의 형태를 가지고 있으며 이는 입체적이고 닫힌 형태적 특성을 가진다.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.416-423
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• 2015

It had been disputed how to apply wall drag to the dispersed phase in the framework of the conventional two-fluid model for two-phase flows. Recently, Kim et al. [1] introduced the volume-averaged momentum equation based on the equation of a solid/fluid particle motion. They showed theoretically that for dispersed two-phase flows, the overall two-phase pressure drop by wall friction must be apportioned to each phase, in proportion to each phase fraction. In this study, the validity of the proposed wall drag model is demonstrated though one-dimensional (1D) simulations. In addition, it is shown that the existing form loss model incorrectly predicts the motion of the dispersed phase. A new form loss model is proposed to overcome that problem. The newly proposed form loss model is tested in the region covering the lower plenum and the core in a nuclear power plant. As a result, it is shown that the new models can correctly predict the relative velocity of the dispersed phase to the surrounding fluid velocity in the core with spacer grids.

• 한국정밀공학회지
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• 제18권1호
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• pp.44-55
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• 2001

The flow behavior of semi-solid materials (SSM) is required to assist the industrial application of thixoforming technology. Particularly, to reduce many lead times, many numerical analysis packages have been developed to simulate required metal forming processes. The objectives of the development of SEMI-FORM for thixoforming process design are to predict the effect of various process variables such as pressing force, die temperature, and die velocity. However, there have not been any reports which adapt these packages to the specific characteristics of SSM. SO, this paper presents an overview of the development of thixoforming simulator of SEMI-FORM. The solver and post-processor of SEMI-FORM S/W for an automated thixoforming process design with arbitrarily shaped die are composed of FORTRAN Power Station 4.0 and Visual Basic 5.0, respectively. This developing SEMI-FORM S/W would be very useful for thixoforming practitioners and engineers to select the optimal process conditions to produce automotive parts with high quality.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.227-231
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• 2004

Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.