• 대한기계학회논문집A
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• 제24권7호
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• pp.1703-1711
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• 2000

Microstructural morphology of molded composites of thermotropic liquid crystalline polymer(LCP) and polyamide 6 (PA6) has been studied as a function of epoxy fraction. Injection-moulding of a thin composite plaque at a temperature below the melting point of the LCP fibrils by suing the extruded LCP/PA6 pellets produced multi-layered structures: 1) the surface skin layer with thickness of 65-120 ym exhibiting a transverse orientation, 2) the sub-skin layer with an orientation perpendicular to the surface skin, i.e. in the flow direction, 3) the core layer with arc-curved flow patterns. Similar microstructural orientations were observed in the respective layers for the composite plaques with different fractions of epoxy.

• Preventive Nutrition and Food Science
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• 제20권3호
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• pp.162-168
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• 2015

Lotus (Nelumbo nucifera Gaertn.) seed is widely used as a traditional medicine in countries of Asia. Among many functions of the lotus seed, one interesting activity is its skin protection from the sunlight and scar. In this study, we focused on the skin protective property of lotus seed tea against ultraviolet B (UVB) irradiation. Two groups of a hairless mouse model, water as control (water group) and lotus seed tea (LST group), were administrated a fluid drink water for six months. After 6 month of administration, UVB exposure was carried out to both groups for another 3 months. During and after the administration, the skin moisture content and the morphological and histopathological analyses through biopsy were carried out. Prior to UVB irradiation, no significant difference was discovered in the skin moisture content for the water group and LST group (P<0.05). However, drastic changes were observed after the UVB treatment. The LST group showed a clear evidence of skin protection compared to the control group (P<0.05). The moisture content, epidermal and horny layer thickness, and protein carbonyl values all revealed that the intake of the lotus seed tea enhanced protection against UVB exposure. As a result, the long-term intake of the lotus seed tea showed the effect of preventing loss of skin moisture, mitigating the formation of abnormal keratinocytes, and contributing to protein oxidation inhibition.

• 혜화의학회지
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• 제20권1호
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• pp.1-10
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• 2011

By studying the portions and layers(分部), left and right, superior and inferior, location of yin and yang, and beginning and end of diseases of skin, which is the core point of the theory of cutaneous region(皮部論) in "Naejing(內經)", in the physiological and pathological perspective, based on opinion of historic memorial doctors, arrived to the conclusion as below. Cutaneous region means not only the distribution of three yin and three yang(三陰三陽) of the surface, but also inside and outside, shallowness and depth, and it is the system which unites meridians, networks, and vessels. It is divided into portions and layers. The origin and beginning of diseases and the rule of favorable pattern and unfavorable pattern can be known through it. The portion of skin is not only the area that meridian vessels belongs to skin, but also the area that activation of twelve meridian vessels are expressed in the surface. The layer of skin is consisted in order of skin-tertiary collateral vessel-collateral vessel-meridian vessel-bone. In "Naejing", there are two preconditions to divide three yin and three yang into yin and yang. The first is standing while looking the south, and second is the quotation "outside is side of yang(外者爲陽 內者爲陰)." According to this preconditions, yang of outside of yang brightness, lesser yang, and greater yang is the whole body, except inside of hand and foot which yin of lesser yin, pericardium, and greater yin. Superior and inferior of the portions and the layers is designated as hand and foot, theological basis of which superior and inferior work in same diagnostic method can be found in the root and the basis(標本) and the origin and the insertion(根結). In conclusion, cutaneous region not only manages layer of the skin, but also it is divided into layers and portions, so it has close relations between meridian vessels and collateral vessels. The in-depth study of cutaneous region and meridians should be progress, in order to practice of diagnosis and acupuncture and moxibustion more.

• 대한조선학회지
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• 제23권1호
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• pp.13-22
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• 1986

Axisymmetric turbulent thick boundary layers on a rotating body of revolution are calculated numerically in the paper. Richardson number is introduced to the mixing length to take account of swirl effects on Reynolds stresses. Interactions of the boundary layer and the external potential flow are included by adding the displacement thickness of boundary layers on the original body. Pressure distributions on the body surface are estimated by integrating normal momentum equation across the boundary layer. A model is designed and tested in the wind tunnel. Mean velocities are measured. Through the present study, swirl effects on the thick axisymmetric boundary layer development are considerable in comparison with those of non-totating cases. Rotational motion generally increase boundary layer thickness, axial skin friction coefficients, and form drags. Circumferential flow can be reversed to induce negative skin friction when the section area is reduced.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.46-50
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• 2005

Smart skin, a multi-layer structure of composed of a round shape antenna, was designed and fabricated. Tests and analyses was conducted to study its behavior under compressive loads. It was confirmed that the designed smart skin failed due to premature buckling before compression failure. Numerical prediction of structural behavior of smart skin by MSC.NASTRAN agreed well with experimental data.

• Animal cells and systems
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• 제11권2호
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• pp.155-160
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• 2007

The skin of the Korean bullheads, Pseudobagrus brevicorpus and P. koreanus, is composed of epidermis, dermis and subcutis. The epidermis has three layers, the outermost layer, middle layer and stratum germinativum. The epidermis consists of two types of gland cells, an unicellular mucous cell of sulfomucin and a large club cell having sometimes two nuclei. The epidermis has numerous intraepithelial blood vessels in P. brevicorpus but not at all in P. koreanus. Lymphatic spaces containing lymphocytes are well developed in mainly the stratum germinativum. The dermis lacks scales and consists mostly of bundles of coarse collagen fibers. The collagen bundles are arranged in parallel to each other in the dorsum and lateral region toward the dorsum, but vertically at intervals in the abdomen and lateral region toward the abdomen. Considering this unique skin structure, the two species are likely to exercise cutaneous respiration as a dual respiratory system to overcome hypoxic conditions which frequently occurs in their habitats.

• 한국환경과학회지
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• 제17권7호
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• pp.809-816
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• 2008

The oriental ore minerals, which mainly consisted of talc, actinolite, sericite, and halloysite were developed, and then used to examine the healing effect on the skin wound in rats. Full-thickness square wounds were formed on the backs of rats after the hairs on the dorsal surface were shaved. The ore minerals were applied to examine the healing effect from day 0 to 15 after wounding. Notable wound healings in terms of congestion around the wound, wound contraction and epithelialization were found in ore mineral-treated groups. Moreover, microscopic results revealed the formation of epithelial layer, hair follicles and progressive angiogenesis in ore mineral-treated groups, while complete epithelial layer could not be found in the control. These results suggest that ore minerals from Korean indigenous ores may have wound healing effect on the skin injury in rats.

• KSBB Journal
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• 제26권4호
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• pp.277-282
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• 2011

The penetration of outside material into skin is not easy. It is since the skin, which is a very hard barrier, protects the body against outside chemical and physical stimulation. Microneedle system which can help improve drug penetration into skin is advancing variously in transdermal drug delivery system (TDDS) in the field of skin care. After inserting microneedle into skin by using electrical or artificial forces, it makes microhole and drug penetration easily and induces natural skin rejuvenation. Diffusion and penetration of drug by optical and electrical force of microneedle is better for fast and effective TDDS. This is more developed than the traditional method such as the manual stamp, roller, and meso gun. The drug absorbed into dermal layer by microneedle helps revive and repair damaged skin. In the future, utilization of microneedle for skin care will progress constantly because of its human-friendly biodegradable materials and the development of the no pain microneedle.

• 대한화장품학회지
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• 제33권2호
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• pp.99-104
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• 2007

피부장벽 기능은 중요한 피부 기능 중 하나로 각질층과 표피층은 다른 피부층 보다 이러한 기능에 있어 큰 역할을 담당하고 있는 것으로 여겨지고 있다. 각질층은 표피 기저층에서부터 표피세포가 위층으로 올라오면서 분화의 과정을 거쳐 형성되게 된다. 이러한 분화 과정은 피부 표면에서 완성되게 되며 지속적으로 올라오는 새로운 각질로 대체되게 되어 건강한 방어막을 형성하게 된다. 본 연구는 tape stripping에 따른 깊이별 여러 인자들의 변화를 살펴봄으로써 각질층의 각 부분의 역할에 대해 살펴보고자 하였다. 피부 표면 수분량에 있어서는 각질층 중 위쪽에 위치하고 있는 uppermost stratum corneum (SC)가 중요한 역할을 하고 있는 것으로 나타났으며 수분증발을 막는 장벽으로써의 역할은 lower SC가 주로 역할을 하는 것으로 나타났다. 그리고 일반적으로 pH는 각질의 산성 pH에서 표피 쪽으로 진행하면서 중성의 pH가 보여지는 것으로 보고되고 있는데 각질층만을 살펴봤을 경우, 아래층으로 내려가면서 오히려 다소 산도가 높아짐을 관찰할 수 있었다. 또한 tape stripping을 통한 각질량 분석에서는 stripping을 거듭할수록 채취되는 각질량도 감소되는 양상을 보여주었다. 본 연구를 통해 수 ${\sim}$ 수십 층으로 구성되는 각질층 중 윗부분은 수분량에, 아래 부분은 장벽으로서의 기능에 있어 역할을 하고 있음을 알 수 있었고 각질층의 깊이가 증가할수록 pH와 각질량은 감소함을 알 수 있었다. 이러한 각질층 내의 위치 차이에 따른 역할에 대한 결과를 통해 화장품 개발에 있어서 다양한 접근이 가능할 것으로 기대되어진다. 또한 본 연구를 통해 각질층도 그 위치에 따라 다른 역할을 담당하고 있음을 간접적으로 알 수 있었고 향후 이러한 점에 초점을 맞춘 특화된 각질 연구도 필요할 것으로 생각되어진다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.101-104
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• 2008

The sailfish is the fastest sea animal, reaching its maximum speed of 110km/h. On its skin, a number of V-shaped protrusions pointing downstream exist. Thus, in the present study, the possibility of reducing the skin friction using its shape is investigated in a turbulent boundary layer. We perform a parametric study by varying the height and width of the protrusion, the spanwise and streamwise spacings between adjacent ones, and their overall distribution pattern, respectively. Each protrusion induces a pair of streamwsie vortices, producing low and high shear stresses at its center and side locations, respectively. These vortices also interact with those induced from adjacent protrusions. As a result, the drag is either increased or unchanged for all the cases considered. In some cases, the skin friction itself is reduced but total drag including the form drag on the protrusions is larger than that of a smooth surface. Since the shape of present protrusions is similar to that used by Sirovich and Karlsson [Nature 388, 753 (1997)] where V-shaped protrusions pointing upstream were considered, we perform another set of experiments following their study. However, we do not obtain any drag reduction even with random distribution of those V-shaped protrusion.