• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권3호
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• pp.189-199
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• 2006

Purpose of study: Partial thickness skin graft is the golden standard regimen for full-thickness skin defect caused by burn or trauma. However, in case of extensive burns of more than 50% of total body surface area, the donor site is not sufficient to cover all defects. As a second choice, allograft, xenograft and synthetic materials have been used to treat skin defect. Among them the amniotic membrane(AM) was used as a biological dressing for centuries because of its potential for wound healing. In this study, quantification of EGF in AM and effect of AM-collagen complex on full thickness skin defects was examined. Materials & Methods: The concentration of EGF in fresh, deep frozen and freeze-dried AM was evaluated by ELISA. EGF-R immunostaining was performed in freeze-dried AM. SD rats weighing 250${\sim}$300g was used for wound healing experiment. Three full thickness skin defects(28mm diameter) were made on dorsal surface of SD rat. The control group was covered by Vaselin gauze and AM-collagen complex and $Terudermis^{(R)}$. was grafted in two other defects. Healing area, Cinamon's score were evaluated before biopsy. Grafted sites were retrieved at 3 days, 1 week, 2 weeks and 4 weeks after operation. H & E and Factor VIII immunohistochemical stain was performed to evaluate the microscopic adhesion and structural integrity and microvessel formation. Results: 1. EGF concentration of fresh, deep frozen and freeze-dried AM showed similar level and EGF-R was stained in epithelial layer of freeze-dried AM. 2. At 4 weeks after grafting, the healing area of AM-collagen and Terudermis group was 99.29${\pm}$0.71% and 99.19${\pm}$0.77 of original size. However, that of control group was 24.88${\pm}$2.90. 3. The Cinamon's score of AM-Collagen and $Terudermis^{(R)}$. group at 4 weeks was 15.6${\pm}$1.26 and 14.6${\pm}$3.13 and that of control group was 3.7${\pm}$0.95. Significant difference was observed among control and experimental groups(p<0.05). 4. Histologic examination revealed that AM protected leukocyte infiltration and epithelial migration was nearly completed at 4 weeks. $Terudermis^{(R)}$. group showed mild neutrophil infiltration until 2 weeks and completion of epithelization at 4 weeks. Control group showed massive leukocyte infiltration until 4 weeks. 5. Microvessels were increased sharply at 1 week and control group at 1 and 4 week showed significant differences with $Terudermis^{(R)}$. group of same interval(p<0.05) but no differences were found with AM group(p<0.05). Conclusion: EGF and EGF-R were well preserved in freeze-dried AM. AM attached to collagen acted as excellent biologic dressing which had similar effect with $Terudermis^{(R)}$. AM showed anti-inflammatory action and healing was completed at 4 weeks after full-thickness skin defect.

• 대한본초학회지
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• 제22권4호
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• pp.279-286
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• 2007

Objective : In order to compare of hyperlipidemia effect of C. wilfordii, C. auriculatum in korea and C. auriculatum in China, it was performed on the hyperlipidemia in rats induced by Triton WR-1339. Method : The 70% MeOH extracts from dried root of C. wilfordii and C. auriculatum in korea and C. auriculatum in china were fractionated into H2O layer and CHCl3 layer. The level of total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, AST and ALT in serum were used to observe the effectiveness of C. wilfordii korean C. auriculatum and chinese C. auriculatum. Results : In the hyperlipidemic rats induced by Triton WR-1339, C. wilfordii and korean C. auriculatum significantly decreased total cholesterol, triglyceride, otherwise significantly increased HDL. And C. wilfordii and chinese C. auriculatum significantly decreased AST and ALT. Conclusion : This study indicate that C. wilfordii korean C. auriculatum and chinese C. auriculatum were effective in the hyperlipidemic rats induced by Triton WR-1339. According to the results, C. wilfordii korean C. auriculatum and chinese C. auriculatum need to considered for the application in hyperlipidemia.

• 한국지반환경공학회 논문집
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• 제3권1호
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• pp.5-12
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• 2002

본 연구에서는 지하수위, 폐기물의 전단강도 정수 그리고 지층 조건이 비위생 매립지 사면의 안정성에 미치는 영향을 검토하였다. 사면의 안정성 해석은 한계평형방법에 근거한 Janbu의 절편법을 사용하였다. 해석 결과 매립지가 완전건조 상태에 있는 경우가 완전포화 상태에 있는 경우에 비해 안전율이 약 2.4~2.8배 정도 증가되었다. 관측된 지하수위 상태 하에서 폐기물의 점착력과 내부마찰각이 증가할수록 사면의 안전율은 선형적으로 증가하였으며, 예상파괴면이 하부지층까지 도달할 경우 하부지층의 조건에 따라 안전율과 예상 파괴면의 형상이 변화한다는 것을 알 수 있었다. 따라서, 폐기물 매립지 건설 시에는 지반조건이 양호한 지반을 선택하고, 지하수위 감소를 위한 차수 및 배수 시스템을 설치하는 것이 사면의 안정성 향상에 도움을 줄 것으로 판단된다.

• 한국식품영양과학회지
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• 제32권7호
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• pp.1059-1065
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• 2003

우리나라 야산에서 손쉽게 구할 수 있는 구황식물인 목단피를 건조시켜 분쇄한 후 methanol과 여러 용매로 추출하여 식품 부패 미생물의 증식 억제 효과를 검색하고 그 항균물질을 분석하여 다음과 같은 결과를 얻었다. 목단피의 methanol 추출물은 1500$\mu\textrm{g}$/mL 농도에서 B. subtilis, L. monocytogenes, V parahaemolyticus의 증식을 100% 억제하였으며 S. aureus, E. coli도 같은 농도에서 각각 36.31%와 67.81%의 억제 효과를 보였다. 목단피의 ethylacetate 분획 추출물은 낮은 농도인 500$\mu\textrm{g}$/disc의 농도에서 식품 부패 미생물 5종 모두에 대하여 clear zone을 형성하여 항균력을 나타내었다. 특히 L. monocytogenes, E. coli균에 대해서는 낮은 농도인 500$\mu\textrm{g}$/disc에서 각각 12mm, 11mm의 clear zone을 형성하였다. 목단피의 ethylacetate추출물을 silica gel colum chromatography(7cm${\times}$1.2 cm)한 후 thin layer chromatography(TLC)를 실시하여 항균 실험을 한 결과 B. subtilis의 경우 500 $\mu\textrm{g}$/disc 농도에서 2nd fra. 1이 21mm, V. parahaemolyticus는 250$\mu\textrm{g}$/disc 농도에서 14mm를 형성하여 목단피의 methanol 추출물로부터 각 용매별로 계통 분획하여 분리한 ethylacetate 분획으로부터 silica gel column chromatograpy와 TLC를 하여 항균성을 보인 2nd fra. 1의 성분을 알아보기 위하여 HPLC로 단일분리하여 얻은 peak Ⅸ에 대한 compound를 GC-MS로 분석한 결과 peak Ⅸ에서는 isobutyl isopentanoate가 있는 것으로 추정되었다.

• 한국세라믹학회지
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• 제20권3호
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• pp.211-216
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• 1983

This work aims at characterizing silicon grains and its compacts. In order to remove iron silicon grains were washed with 5N hydrochloride at 60-7$0^{\circ}C$ for 170 hrs, and then followed the chemical analysis by atomic absorption spectrophotometer X-ray diffraction analysis SEM observation and specific surface area determination by B. E. T. Mixtures of graded silicon particles with two or three different sizes were made into packings by mechanical vibration. The mixtures were used to make compacts with 10 mm in diameter and 70mm in length by isostatically pressing at 1, 208 kg/$cm^2$ (20 kpsi) and 4, 255kg/$cm^2$ (60 kpsi) respectively. Bulk densities of packings and compacts were measured. A slip made of magnesium nitrate solution and fine silicon particles was spray-dried and then decomposed at 30$0^{\circ}C$ for the purpose of coating the uniform layer of magnesium oxide on the surface of particles. The results obtained are as follows: (1) About two thirds of iron content could be removed from silicon by washing silicon powders with hydrochloride. (2) Uniform layer of magnesium oxide on the surface of silicon could be prepared by spray-drying suspension and by decomposing it. (3) B. E. T. specific surface area of fine silicon particles was 2, 826.753$m^3$/kg. (4) In the binary system with two sizes of 40-53$\mu\textrm{m}$ particles and <10$\mu\textrm{m}$ particles the maximum bulk density of packing was 55% of theoretical value and that of compacts made at the pressure of 4, 255 kg./$cm^2$ (60 kpsi) was 73% of theoretical value. (5) In the ternary system with three sizes the maximum bulk density of packing was 1.43 g/$cm^3$and that of compacts was 1.80g/$cm^3$which is equivalent to 77.6% of theoretical value. The composition of the closest compact was consisted of 50% of 40-53$\mu\textrm{m}$ particles 20% of 10-30$\mu\textrm{m}$ particles and 30% of <10$\mu\textrm{m}$ parti-cles.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.152-152
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• 2016

Anodizing is a technology to generate thicker and high-quality films than natural oxide films by treating metals via electrochemical methods. It is a technique to develop metals for various uses, and extensive research on the commercial use has been performed for a long time. Aluminum anodic oxide (AAO) is generate oxide films, whose sizes and characteristics depending on the types of electrolytes, voltages, temperatures and time. Electrochemical manufacturing method of nano structure is an efficient technology in terms of cost reduction, high productivity and complicated shapes, which receives the spotlight in diverse areas. The sulfuric acid was used as an anodizing electrolyte, controlling its temperature to $10^{\circ}C$. The anode was 5083 Al alloy with dimension of $5(t){\times}20{\times}20mm$ while the cathode was the platinum. The distance between the anode and the cathode was maintained at 3 cm. Agitation was introduced by magnetic stirrer at 300 rpm to prevent localized temperature rise that hinders stable growth of oxide layer. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition for $10^{\circ}C$, 10 vol.%, respectively. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant rate. In addition, using galvanostatic method, it was maintained at current density of $10{\sim}30mA/cm^2$ for 40 minutes. The cavitation experiment was carried out with an ultrasonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1 mm. The specimen after the experiment was cleaned in an ultrasonic, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the investigation, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with applied current density.

• 한국식품과학회지
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• 제32권1호
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• pp.31-36
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• 2000

본 연구는 국내산 녹용(사슴뿔의 상대)을 종으로 5개 부위, 횡으로 벨벳층과 스폰지층의 2개 부위로 분할하여 무기질 조성 및 함량을 분석하였다. 회분, Ca, P, Mg, Zn 함량은 tip 부위에서 하단으로 내려갈수록 유의적으로 증가하였으며, Mn, Cu, Fe 함량은 tip 부위에서 하단으로 내려갈수록 유의적으로 감소하였다. 스폰지층은 벨벳층에 비하여 회분 함량이 3배, Ca 함량이 2배 정도 높았으며 대부분의 무기질 함량은 벨벳층에 비하여 스폰지층이 유의적으로 높았다. Tip부위는 다른 부위에 비하여 특히 회분, Ca, P, Cu, Fe 함량 및 Ca/ash(%), Ca/P, Ca/Fe 비에 있어서 현저한 차이를 보였으므로 이러한 성분 및 성분비가 녹용의 품질 지표로 사용될 수 있는 가능성이 제시되었다.

• 한국식품영양과학회지
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• 제42권12호
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• pp.1988-1993
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• 2013

본 연구에서는 불용성 식이섬유가 풍부한 꽃송이버섯을 옐로우 레이어 케이크의 원료로 이용하기 위하여 꽃송이버섯 분말을 밀가루 중량에 대해서 1~8% 수준으로 첨가하여 케이크를 제조하고 버섯 분말의 첨가량에 따른 반죽의 품질특성(pH, 비중, 점도)과 케이크의 품질특성(무게, 부피, 비용적, 굽기 손실률, 색도, 물성) 및 관능적 특성을 조사하였다. 꽃송이버섯 분말을 2% 이하로 첨가한 반죽은 대조군과 유사한 품질특성을 나타내었다. 꽃송이버섯 분말의 첨가량이 증가함에 따라 케이크의 부피, 비용적, 굽기 손실률은 감소하는 경향을 나타내었고 케이크 껍질과 내부의 색상 모두 어두워지는 현상이 관찰되었다. 꽃송이버섯 분말의 첨가량이 늘어날수록 케이크의 물성 중 경도, 검성, 씹힘성은 감소하는 경향을 나타내었으며 저장 중 경도 변화도 적었다. 관능검사 결과 꽃송이버섯 분말을 2% 이하로 첨가한 케이크는 꽃송이버섯 분말을 첨가하지 않은 케이크보다 관능적 특성이 우수한 것으로 평가되었으나 첨가량이 4% 이상에서는 케이크의 기호성이 오히려 감소하는 것으로 나타났다. 이상의 실험 결과를 종합해 보면 꽃송이버섯 분말 첨가 옐로우레이어 케이크의 제조 시 꽃송이버섯 분말의 첨가량은 2%가 가장 적합한 것으로 판단되었다.

• Journal of the Korean Wood Science and Technology
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• 제36권4호
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• pp.19-25
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• 2008

유리섬유강화플라스틱(GFRP : Glass fiber reinforced plastic) 보강 집성재를 제작한 후 유리섬유강화플라스틱의 체적비에 따른 휨강도 성능을 평가하였다. 집성재 제작에는 평균함수율 8%, 비중 0.54의 국산 낙엽송(Larix kaempferi Carr.) 제재판($2cm(h){\times}10cm(b){\times}360cm(l)$)을 7층으로 적층하여 집성재($10cm(b){\times}14cm(h){\times}180cm(l)$)를 제작하였다. 유리섬유강화플라스틱은 인장응력을 받는 하층의 최외각층과 윗층 사이에 두께 0.1 cm (체적비 0.7%)와 0.3 cm (체적비 2.1%)로 보강하였다. 유리섬유강화플라스틱을 체적비 0.7% 보강한 집성재의 경우 Control 집성재보다 휨강도가 12% 정도 증가하였으며 체적비 2.1%를 보강한 집성재의 경우 휨강도가 28% 정도 증가하였다. 또한, 유리섬유강화플라스틱 보강층이 파단의 진행을 억제하였으며 파괴되지 않은 부분은 약 90%의 휨강도를 유지하고 있었다. 접착성능 평가 결과 블록 전단 강도는 KS F3021의 합격기준 $7.1N/mm^2$를 만족하였으며 침지박리시험과 삶음박리시험 결과 박리율 5% 이하로 접착성능도 양호하였다.

• Journal of the Korean Wood Science and Technology
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• 제21권1호
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• pp.21-38
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• 1993

In order to investigate the influence of recycling, a laboratory method simulating the papermaking process was used for assessing the effects of recycling on fiber properties. Sw-BKP, Hw-BKP and BGP were disintegrated and beaten to about 42$^{\circ}$SR-44$^{\circ}$SR by a valley beater. After beating, these pulps were dewatered by centrifuge and dried at 90$^{\circ}C$ for 72hrs. This recycling process(sequence of wetting, defiberating, dewatering and drying) was repeated seven times. Physical, mechanical and optical properties of recycled pulps were evaluated by TAPPI Standards. Morphological changes occurred through recycling process was observed by SEM. Sheet density decreased with recycling. The largest drop in density occurred during the first recycling. The porosity values decreased with recycling. Mechanical properties such as tensile, burst strength and folding endurance, decreased with recycling. However tear strength of Sw-BKP and mixtured pulp increased at the first recycling. Optical properties such as brightness, opacity and light scattering coefficient, increased with recycling. However, brightness of mixtured pulp gradually decreased with recycling. Fibrillated outer layer of the fiber was gradually removed from the surface with recycling. As a result of recycling, crinkles on the fiber surface were found to be more folded.