• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 C
• /
• pp.1354-1356
• /
• 1994

In order to protect cable from rat's biting, a development of rodent repellent is described. This cable has double coated sheath such as construction of skin layer over the conventional cable sheath. Stabilized rodent repellent agent which has good compatibility with PVC is employed in a skin layer. Rodent repellent layer has highly residual properties of agent through the manufacturing process, and meets the general requirements of cable sheath. Also, rat repellent effect is excellent.

• Applied Microscopy
• /
• 제28권3호
• /
• pp.329-343
• /
• 1998

Early wound healing responses in the skin of the Korean fire bellied toad, Bombina orientalis, were examined using histochemical , scanning and transmission electron microscopical techniques. Cutaneous wounds were induced by sharp razor blade , and maintained in special cages for up to 3 days. By this treatment whole parts of epithelium and dermis were profoundly affected. After injury, retraction of damaged surface of the skin was observed. At 3 hours after injury, poly-band was form by mucous substance. The wound skin consisted of mucous gland secreted mucous substance which flows into wound cavity and the wound area was sealed by mucous substance which form thick layer at 6 hours. It appeared that natural disposition showed acid and neutral mucous substance by reaction of PAS and Alcian blue (pH 2.5) staining. After formation of the poly-band, epithelial cells were formed by migration of regenerating epithelial cells. These cells moved over the wound surface by migration at 12 hours after wounding. Poly-band was much increased in thickness and migrating cells were completely formed wound closure at 24 hours post-wounding. After 72 hours regenerated epithelial layer consists of four or five cell layers which are similar to clear, granular, and spinous layer.

• 한국어류학회지
• /
• 제11권2호
• /
• pp.109-116
• /
• 1999

한국산 미꾸리 Misgurnus anguillicaudatus의 피부 구조 및 조직화학적 특정을 조사하기 위해 등, 측면, 복부, 머리부분의 피부를 조사하였다. 미꾸리의 epidermis는 elongated mucous cell과 club cell의 2개의 gland로 구성되었으며 두께는 아주 두꺼웠다. mucous cell은 acid mucopolysaccharides의 물질을 분비하였으나 club cell은 mucopolysaccharides에 어떠한 반응도 보이지 않았다. 표피의 기저층은 림파구를 가지는 lymphocytic space가 발달하였으며 기저막과 상피세포사이에 배모양의 감각세포인 pit organ이 존재하였다. Dermis의 stratum laxum에는 acid mucopolysaccharides를 나타내는 부분(a definite area)이 존재하며, 이러한 물질은 비늘에도 분포하고 있다. 작은 비늘이 dermis속에 파 묻혀 있으나 머리부분에는 없다. 또한 많은 양의 모세혈관들이 기저막 바로 아래에 존재하였다. 피부의 이러한 특징들은 미꾸리가 공기를 이용하는 피부호흡과 밀접한 관계가 있다.

• Imaging Science in Dentistry
• /
• 제32권1호
• /
• pp.11-18
• /
• 2002

Purpose: To evaluate cultured human artificial skin as an experimental model for studying radiation effects in vitro. Materials and Methods: The skin was constructed by culturing keratinocytes over collagen lattice which made by culturing fibroblasts. Two groups were irradiated to gamma rays at single dose of 25 Gy with or without 3.5% of DMSO. Ultrastructures were investigated by electron microscopy after irradiation. The number of epidermal layers and expression of cytokeratin (CK) 14 & 10 were also seem by light microscopy. Results: At 2 days after irradiation in experimental group without DMSO, necrotic cells were rarely found in the spinosal layer and undercornified cells were visible in the homey layer. Similar findings were also found in experimental group with DMSO but in mild form. The number of epidermal layers in experimental group without DMSO were significantly fewer than other group. CK 14 expressed in all the layer excluding homey layer but CK 10 expressed over 3∼4 basal layers. Such patterns of CK expression were similar to all groups. It is suggested that structures of the keratinocytes and epidermal formation could be disturbed by irradiation in artificial skin and that DMSO can protect these damages. Conclusion : Therefore this work could be used as an organotypic experimental model in vitro using human cells for studying radiation effect in skin. Furthermore structural findings provided in this study could be used as useful basic data in further study using this model.

• 대한기계학회논문집B
• /
• 제21권3호
• /
• pp.427-435
• /
• 1997

Conditional sampling techniques are utilized to investigate the relation between the wall skin-friction and stream wise velocity fluctuations in a turbulent boundary layer. Conditionally averaged results using a peak detection and the VITA (variable-interval time-averaging) technique show that a high skin friction is associated with high frequency components of the wall skin-friction fluctuations. The conditionally averaged wall skin-friction fluctuations obtained by using the VITA technique have a positively-skewed characteristics compared with the conditionally averaged stream wise velocity fluctuations. It is confirmed that there exists a phase shift between the wall skin-friction and stream wise velocity fluctuations, which was also found from the long-time averaged space-time correlations. The amount of phase shift between the wall skin-friction and stream wise velocity fluctuations is the same as that from the long-time averaged space-time correlations and does not change despite the variation of the detection threshold.

• Journal of Microbiology and Biotechnology
• /
• 제32권2호
• /
• pp.238-247
• /
• 2022

Since the skin covers most surfaces of the body, it is susceptible to damage, which can be fatal depending on the degree of injury to the skin because it defends against external attack and protects internal structures. Various types of artificial skin are being studied for transplantation to repair damaged skin, and recently, the production of replaceable skin using three-dimensional (3D) bioprinting technology has also been investigated. In this study, skin tissue was produced using a 3D bioprinter with human skin cell lines and cells extracted from mouse skin, and the printing conditions were optimized. Gelatin was used as a bioink, and fibrinogen and alginate were used for tissue hardening after printing. Printed skin tissue maintained a survival rate of 90% or more when cultured for 14 days. Culture conditions were established using 8 mM calcium chloride treatment and the skin tissue was exposed to air to optimize epidermal cell differentiation. The skin tissue was cultured for 14 days after differentiation induction by this optimized culture method, and immunofluorescent staining was performed using epidermal cell differentiation markers to investigate whether the epidermal cells had differentiated. After differentiation, loricrin, which is normally found in terminally differentiated epidermal cells, was observed in the cells at the tip of the epidermal layer, and cytokeratin 14 was expressed in the lower cells of the epidermis layer. Collectively, this study may provide optimized conditions for bioprinting and keratinization for three-dimensional skin production.

• 한국조리학회지
• /
• 제19권3호
• /
• pp.33-45
• /
• 2013

본 연구는 커피 실버스킨을 밀가루 중량에 대해서 0%, 3%, 5%, 7%로 대체 첨가하여 옐로우 레이어 케이크의 특성을 알아보았다. 반죽의 비중은 실버스킨 첨가량이 증가할수록 유의적으로 증가하였으며, 비용적은 실버스킨 함량이 많을수록 유의적으로 감소하였다. 부피지수는 실버스킨 첨가량이 증가함에 따라 유의적으로 감소하였으며, 대칭지수와 균일지수는 유의적인 차이가 없었다. 대조구의 부피지수, 대칭지수와 균일지수가 가장 높게 측정되었다. 조직감에서는 대조구가 가장 낮은 경도와 가장 높은 탄력성을 나타내었다. 시간이 경과함에 따라 실버스킨 첨가량이 많을수록 경도는 높아졌으나 탄력성은 낮아졌다. 관능검사 결과, 조직감을 제외한 모든 항목에서 대조구에 비해 실험군의 수치가 높았으며, 그 중에서 향과 맛은 SS5가 가장 높았고 외관과 전체적인 기호도는 SS3이 가장 높았다.

• 동력기계공학회지
• /
• 제17권6호
• /
• pp.95-101
• /
• 2013

A stereo PIV measurements in a circulating water channel has been performed to investigate the skin friction reduction mechanism of the outer-layer vertical blades first devised by Hutchins. In a recent PIV measurement study, considerable skin friction reduction was achieved as much as 2.73%~7.95% by outer-layer vertical blades array. In the present study, the influence of vertical blades array upon the characteristics of the turbulent coherent structures was analyzed by proper orthogonal decomposition method. It is observed that the vortical structures are cut and deformed by blades array and also the turbulent intensity and the Reynolds stress were weakened by the blades. These phenomena strongly associate the skin-friction drag reduction mechanism in the turbulent boundary layer flow.

• Composites Research
• /
• 제12권6호
• /
• pp.53-64
• /
• 1999

LCP원섬유(fibril)와 폴리아미드6 (PA6)수지로 사출성형된 복합재료 박판(molded thin composite plaques)의 미세구조와 굽힘강도에 대한 에폭시수지 함유율의 효과를 살펴보았다. 성형은 LCP원섬유의 용융점 이하에서 하였으며 이렇게 만들어진 판재는 횡방향 배향을 보이는 두께 $65-120{\mu\textrm{m}}$의 표피층(surface skin layer), 유동방향과 거의 일치하는 배향을 보이는 표피아래층(sub-skin layer), 아크형 곡선유동형태를 보이는 심층(core layer)으로 구성되어 있었다. 에폭시함유율이 달라도 각 층의 미세구조방향은 유사하였으나 에폭시함유율이 증가함에 따라 LCP영역(domain)이 원섬유상에서 층상구조로 변했고 거시적 파괴진로(fracture path)는 인장형에서 전단형으로 바뀌었다. 또한 에폭시 4.8vol%에서 가장 우수한 굽힘강도와 파단변형율을 보였다. 굽힘강도를 수치해석한 결과 에폭시성분을 복합재에 부가하면 각 층의 두께와 미세구조 같은 기하학적인 형태가 변하면서 각 층 자체의 탄성계수와 강도가 열등화 되었음을 알았다.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 추계학술발표대회 논문집
• /
• pp.61-64
• /
• 2004

The strength characteristics as well as deformation behaviors of honeycomb sandwich composite (HSC) structures were investigated under bending in consideration of various failure modes such as skin layer yielding, interface-delamination, core shear deformation and local buckling. Deformation behaviors of honeycomb sandwich plates were observed with various types of aluminum honeycomb core and skin layer. Their finite-element analysis simulation with a real model of honeycomb core was performed to analyze stresses and deformation behaviors of honeycomb sandwich plates. Its results were very comparable to the experimental ones. Consequently, the increase in skin layer thickness and in cell size of honeycomb core had dominant effects on the strength and deformation behaviors of honeycomb sandwich composites.