• Composites Research
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• v.25 no.1
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• pp.1-8
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• 2012

In order to predict the thermoelastic behavior of porous composites, poroelastic parameters are measured by using micromechanics-based finite element models. The expanding deformation caused by pore pressure, and the degradation of homogenized elastic moduli with pores are calculated for the assessment of the poroelastic parameters. Various representative volume elements considering the shape, size, and array pattern of pores are modeled and analyzed by a finite element method. The effects of porosity and material anisotropy, and the distribution of stain energy density are investigated carefully. In addition, the measured poroelastic parameters are verified by predicting the thermo-pore-elastic behavior of carbon/phenolic composites.

• Journal of Technologic Dentistry
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• v.8 no.1
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• pp.101-105
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• 1986

• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.323-327
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• 1997

Addition of growth inhibitors such as ancymidol, ABA, chloromequat, and pachlobutrazol into MS medium had no effect to preventing vitrification in cultures of Rehmania glutinosa. Anatomical investigation revealed that vitrified thick leaf tissue in vitro had larger intercellular space with poor development of sponge and pallisade tissue compared to those of in vitro grown glaucous and field grown plants. In vitro grown glaucous leaf had smaller and round type stomata showing distinguishable guard and subsidiary cell than those of reestablished plantlets into soil whereas abnormal stomata and poor development of epicuticular wax on the surface of leaf was observed in verified plantlet.

• Korean Journal of Plant Taxonomy
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• v.48 no.2
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• pp.143-152
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• 2018

A comparative study of leaf epidermal microstructures in genus Aruncus (two species, five varieties) was carried out using scanning electron microscopy in order to evaluate their significance in terms of taxonomy. All of the leaves of the taxa studied here were amphistomatic with undulate anticlinal walls, and smooth and flat periclinal walls on both surfaces. The size range of the stomata complex is $8.95-21.97{\times}7.50-16.99{\mu}m$: the largest one was found in Aruncus dioicus var. astilboides (average $18.01{\times}13.47{\mu}m$) and the smallest was measured and determined to be A. gombalanus (average $11.11{\times}8.94{\mu}m$). An anomocytic stomata complex was found in all of the studied taxa. The stomatal frequency on average was $27.54/0.05mm^2$; it is highest in A. gombalanus ($60.4/0.05mm^2$) and lowest in A. dioicus var. acuminatus ($11.6/0.05mm^2$). Two types (short stalked capitate glandular trichome and non-glandular trichome) of trichomes are found in the leaves. The non-glandular trichome was divided into three types based on the presence and degree of development of subsidiary cells. Anomocytic stomata of the hypostomatic type and the distribution pattern of capitate glandular trichomes were the major characters in this genus. The stomata size and frequency, the epidermal cell structure, the trichome type and the distribution pattern may have diagnostic importance among the taxa in the genus. Our leaf micromorphological results provide useful information for the taxonomic revision of the genus Aruncus.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.2
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• pp.61-67
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• 2005

In this study a new growing method of silicon nitride whiskers in the inside of large pores made intentionally during the sintering was conducted. Pore size, pore vol%, and nitrogen pressure were used as experimental variables. Silicon nitride whiskers were well grown in the inside of pores with low pore vol% range from 14 to 27 but not grown with high pore vol% such as 39 and 50. On the other hand, pore size and nitrogen pressure did not have any influence on the whisker growth. Therefore the most important factor to grow silicon nitride whisker in the inside of large pores during sintering was to make pores isolated or closed.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.185-194
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• 1998

Flow-induced voids during resin impregnation and poor fiber wetting give serious effects on the mechanical properties of composites in resin transfer molding process. In order to better understand the characteristics of resin flow and to investigate the mechanism of void formation, flow visualization experiment for the resin impregnation was carried out on plain weaving glass fiber mats using silicon oils with various viscosity values. The permeability and the capillary pressure for the fiber mats of different porosities were obtained by measuring the penetration length of the resin with time and with various injection pressure. At low porosity and low operating pressure, the capillary pressure played a significant role in impregnation process. Video-assisted microscopy was used in taking the magnified photograph of the flow front of the resin to investigate the effect of the capillary pressure on the void formation. The results showed that the voids were formed easily when the capillary pressure was relatively high. No voids were detected above the critical capillary number of 2.75$\times$$10^{-3}, and below the critical number the void content increased exponentially with decrease of the capillary number. The content of void formed was independent of the viscosity of the resin. For a given capillary number, the void content reduced with the lower porosity of the fiber mat.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.266-269
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• 1998

세 번수 단사로 제직된 모직물은 그 사용도가 높아지고 있으나 의복의 형태안정성이 문제되고 있다. 형태안정성 중에서 특히 공기중 수분의 흡수, 발산에 따른 수분율의 차이로 발생하는 습윤팽창은 시임 퍼커링, 의복의 뒤틀림, 의복 사이즈의 불량, 접착심지의 이탈등의 다양한 의복 외관상의 문제점을 야기시킬수 있다$^{1-4)}$ . 이러한 모직물의 습윤팽창은 직물의 길이와 두께를 변화시켜서 기공도에 영향을 미치고 나아가 의복의 쾌적감에도 영향을 미치게 된다.(중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.27-27
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• 2018

알루미늄은 취약한 내식성을 보완하기 위하여 나노다공성의 산화물 피막을 형성하는 양극산화 처리를 주로 활용한다. 이러한 나노다공성 산화물 피막에 소수성 처리와 불용성의 윤활유를 침지하면 표면에 접촉하는 물을 비롯한 다른 유체들의 젖음성을 크게 감소시킬 수 있으며, 이로 인하여 부식성 물질이 다공성 구조물로 침입하는 것을 억제할 수 있다. 따라서 양극산화 피막에 윤활유 침지를 이용하여 알루미늄의 부식에 대한 저항성을 크게 향상시킬 수 있으며, 추가적으로 외부의 물리적인 손상에 대한 치유 능력을 얻을 수 있다. 이러한 성능뿐만 아니라 침지된 윤활유의 내구성은 나노다공성 산화피막의 물리적 형상에 따라 차이가 날 수 있다. 본 연구에서는 나노다공성의 양극산화 피막의 기공 구조를 다양하게 변화시켜 그 형상에 따라서 윤활유를 침지 후 알루미늄 소재의 내식성 및 자기 치유 특성의 차이에 대하여 알아보았다. 기공의 형상은 한쪽 끝이 막혀있는 기둥형, 후처리를 통한 확장된 기둥형 및 침상형의 기공 구조를 제조하였고, 전압제어를 통한 병목 형상의 기공 구조를 구현하여 그 특성 차이를 비교하였다. 기공들이 서로 고립된 형태를 가질수록 윤활유가 안정적으로 산화물에 침지될 수 있으며, 기공의 공간이 클수록 더 많이 윤활유를 포함하여 우수한 자기 치유 특성을 보여주었다. 병목 형상의 가공 구조는 내부의 충분한 크기의 기공 공간과 표면에 작은 기공을 가지고 있기 때문에 우수한 내구성과 자기 치유 특성을 보여준다.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.206-210
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• 2002

The bread qualities were analyzed objectively by using CrumbScan software. Samples were prepared at the same conditions of mixing, fermentation, and baking time except the amount of Korean wheat flour (KWF). The bread volume was increased with increasing KWF, and the maximum volume was attained in the product of 20% KWF. Although the products of 20% and 30% KWF showed the same thickness of the crust, the crust was thinner than control when KWF was added. The size (fineness) and shape (elongation) of crumb cells were larger and rounder than control due to the low degree of elasticity of the KWF-added dough. Among the samples, the product with 20% KWF showed the most even distribution of crumb cells around the sliced area. The precise determination of external and internal characteristics of the bread was possible with Crumbscan, suggesting the possibility of developing industrial standards for bread.

• Proceedings of the Korean Society of Crop Science Conference
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• 1988.07a
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• pp.30-31
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• 1988