• 한국응용과학기술학회지
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• 제37권5호
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• pp.1248-1256
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• 2020

In this study, the polyurethane resin was synthesized by applying PTMG and DMBA of different composition ratios for the synthesis of water-dispersible polyurethane used in wound coating resin. The varying properties of the synthesized water-dispersible polyurethane were measured through tensile strength, elongation, and abrasion resistance analysis. As for the tensile strength measurement result according to the PTMG content, the sample with the highest reaction molar ratio was measured as 1.08 kgf/mm2 and the elongation was measured as 520%. As for the tensile strength result according to the DMBA content, the sample with the highest reaction molar ratio was measured as 0.51 kgf/mm2, and the elongation was measured as 435%. The degree of surface destruction by the abrasion resistance measurement was visually confirmed through SEM.

• 한국응용과학기술학회지
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• 제38권1호
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• pp.178-185
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• 2021

본 연구에서는 폴리비닐알콜(PVA)와 폴리프로필렌글리콜(PPG)기반의 창상피복용 수분산 폴리우레탄수지를 합성하였으며, 시료의 물리적 특성을 필름 시료와 피혁(Full-Grain) 표면에 코팅을 하여 물리적 특성 변화를 연구하였다. 인장강도의 경우 PVA가장 적게 반응된 PUD-PA1 2.00 kgf/㎟ 으로 가장 높은 저항성을 보였으며. 마찬가지로 연실율은 PVA가장 적게 반응된 PUD-PA1가 554%로 높게 측정되었다. 내마모성 측정 결과 PVA 반응이 증가함에 따라 표면의 강도나 낮게 36.77 mg.loss로 감소됨을 알수 있었다.

• 공업화학
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• 제34권2호
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• pp.186-191
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• 2023

The goal of this study was to use gelatin to modify the surface of fibroin microspheres to enhance their biofunctionality for tissue engineering and regenerative medicine applications. Three different methods were used for the modification: coating, incorporation, and covalent bonding. Wound-healing assays demonstrated that gelatin modification of fibroin microspheres enhances 3T3 and HDF cell migration. Although the level of gelatin coverage varied depending on the method used, there was no significant difference between the modified microspheres. The gelatin-modified microspheres also increased the migration velocity of individual 3T3 cells. The results suggest that gelatin modification of fibroin microspheres is a promising approach for developing functional biomaterials with enhanced biological properties. Further optimization of gelatin modification is necessary to maximize the biofunctionality of fibroin microspheres.

• 대한화장품학회지
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• 제41권4호
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• pp.401-411
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• 2015

본 연구에서는 피부재생 화장품 소재로 활용하고자 저분자화 시킨 Polydeoxynucleotide (PDRN)의 창상 치유 효과를 조사하였다. 이를 위하여 연어 정소 유래 PDRN 단백질 제거공정, 내독소 제거공정을 거쳐 순수분리 정제하였고 분자량 저감공정을 거쳐 기존 PDRN 보다 피부 침투율을 높인 고순도 PDRN을 제조하였다. 상처 치료 과정 중 PDRN 처리에 의한 효능을 평가하기 위해 sprague-dawley rats (SD)의 배부에 bioxy punch를 이용한 4개의 창상을 유발하고, 시료를 포함한 총 5종의 실험시료를 마리당 $500{\mu}L$씩 도포한 후 7일 간격으로 4주간 피부조직 변화를 관찰하였다. 상처에 PDRN을 도포한 후, 절개된 상처의 표피화와 수축이 더 빨라졌고, 창상면적에 있어서 PDRN의 도포는 양성대조군인 $Fucidin^{(R)}$ 도포군과 비교하여 유의하게 줄어들었다. 염색한 조직의 현미경 관찰 결과에서는 양성대조군이 가장 빠르게 재상피화가 이루어졌으며, 그 다음으로는 PH군, PD군, HA군으로 교원질 재합성 및 형성 수준을 보였다. 또한, 병변의 형질전환성장인자($TGF-{\beta}$) 및 혈관 내피성장인자(VEGF) 등의 성장인자에서도 염색 조직의 결과와 유사하게 나타났다. 이러한 결과를 종합하여 볼때, 저분자화된 PDRN은 창상에 치료효과가 있다고 판단되며, 화장품 및 의료산업 분야의 기능성 소재로 활용 가능할 것으로 판단되어 진다.

• 한국안전학회지
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• 제20권4호
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• pp.14-19
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• 2005

One area in which composites have been used rather extensively is for fabricating pressure vessel. These structures can be readily manufactured by filament winding, which is, as far as composite fabrication techniques are concerned, a relatively inexpensive method for producing composite structures. Unfortunately, the higher strength material and fabrication costs are not the only disadvantages of fiber-reinforced polymer composites when they are compared to metals. Additionally, these materials tend to exhibit brittle behavior. This is of particular concern when they are subjected to a low-velocity impact during routine handling a significant amount of structural damage can be introduced into the composites. The goals of this paper are to understand the impact damage behavior and identify the effect of surface coating materials on impact resistance in filament wound composite pressure vessels. For these, a series of low velocity impact tests was performed on specimens cutting from the full scale pressure vessel by the instrumented impact testing machine. The specimens are classified into two types with and without surface protective material. The visualization for impact damage is made by metallurgical microscope. Based on the impact force history and damage, the resistance parameters were employed and its validity in identifying the damage resistance of pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the protective material were evaluated quantitatively.

• Archives of Reconstructive Microsurgery
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• 제24권2호
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• pp.79-81
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• 2015

Rheumatoid arthritis is a long lasting autoimmune disorder that primarily affects joints, and patients with rheumatoid arthritis are predisposed to development of chronic skin ulcers. In addition, skin ulcers with rheumatoid arthritis tend to persist despite treatment because of sustained inflammation and poor healing capacity. Treatment of skin ulcers involves medications, wound coating agents, and surgical procedures including skin grafting, however, wound dressing or skin grafts are generally excluded because of excessive cost and time and poor intake rate. The dorsal metacarpal artery perforator (DMAP) flap, a vascular island flap for coverage of soft tissue defects on the fingers, provides promising results including matched quality and color. We experienced a case of DMAP flap for reconstruction of a rheumatoid ulcer, and a DMAP flap may be considered as a good faithful option for treatment of patients with rheumatoid ulcer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권1호
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• pp.9-14
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• 2001

With the object of providing a temporary artificial periodonal ligament-like membrane around the dental implant, 10 Branemark type implants were coated with commercially available chitosan(Fluka Co., Buchs, Switzerland) which has a molecular weight of 70,000 and 80% deacetylation degree. Once this bioactive hydrophillic polymer(chitosan) contacts with blood or wound fluids, it becomes swollen and penetrates into the adjacent cancellous bone. Thus the interface between implant and surrounding bone is completely filled with chitosan. This tight junction in early healing phase enhances primary stability. The chitosan coated dental implants were implanted into the fresh patella bones from porcine knees, since the thickness of cortical bone is relatively even and their cancellous structure is homogenous. To test the shock absorbing effect, 1mm delta-rogette strain gage was installed behind the implant. The results showed 1. The principal strain peak value directed to the impact of coated implant was 0.064 0.018(p<0.05) and that of uncoated implant was 0.095(0.032 p<0.05). 2. The peak time delay of coated implant was 0.056sec(0.011 p<0.05) and that of uncoated implant was 0.024sec(0.009 p<0.05). It can be reasoned from this results that the chitosan coating has a shock absorbing effect comparable with a temporary artificial periodontal ligament.

• 한국초전도ㆍ저온공학회논문지
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• 제7권3호
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• pp.9-12
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• 2005

[ $Y_1Ba_2Cu_3O_{7-8}$ ] (YBCO) coated conductor has been fabricated by batch-type process using oxide-precursor-based metal-organic deposition (MOD) method. The batch-type process can be scaled up more simply to Produce long-length YBCO conductor than the reel-to-reel process. Also, it has less handling problems and is adequate to the ambient gas environment. In this work, YBCO oride powder was used as a starting precursor for MOD method. After reel-to-reel dip coating process, me ter-long-buffered metal tape was wound around a cylinder and underwent calcination and annealing processes. Annealed YBCO films showed good c-axis alignment and dense surface morphology with no cracks, but exhibited very low critical current density of $10^5\;A/cm^2$.

• 한국가스학회지
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• 제17권6호
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• pp.15-19
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• 2013

이 논문은 자동차 엔진룸에서 전기적인 접촉불량에 의한 단락현상과 엔진의 뜨거운 열에 의해 가연성 물질과 접촉하여 화재가 발생된 원인을 분석하고 연구하는 것이다. 첫째, 배터리에서 시동모터로 연결되어 있는 배터리 전원선이 자동변속기 상단에 배선을 고정시켜 주는 브래킷(Bracket) 볼트 이완으로 차체와의 단락 현상에 의해 화재가 발생된 것을 확인하였다. 둘째, 배터리에서 시동모터까지 가는 배선에 감은 절연테이프가 녹아 단락현상에 의해 화재를 일으킨 것을 확인하였다. 셋째, 냉각 팬 배선이 이완되어 과열된 엔진의 열에 의해 배선이 융착되어 화재가 발생된 것을 확인하였다 따라서, 엔진에 관련된 시스템의 화재는 엔진 및 각 시스템의 손상으로 자동차 탑승객을 위험에 처하게 하며, 화재 후 자동차는 재사용이 어렵게 되므로 시스템의 철저한 관리와 세심한 주의가 요구되어진다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.203-204
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• 2006

Studies on some biodegradable polymers and other materials such as hydrogels have shown the promising potential for a variety of surgical applications. Postoperative adhesion caused by the natural consequence of surgical wound healing results in problems of the repeated surgery. Recently, scientists have developed absorbable anti-adhesion barriers that can protect a tissue from adhesion in case they are in use; however, they are dissolved when no longer needed. Although these approaches have been attempted to fulfill the criteria for adhesion prevention, none can perfectly prevent adhesions in all situations. Overall of this work, a new method to fabricate an anti-adhesion membrane using biodegradable polymer and hydrogel has been developed. The ideal barrier for preventing postoperative adhesion would have the following properties; it should be (i) resorbable (ii) non-reactive (iii) easy to apply (iv) capable of being fixed in position. In order to fulfill these properties, we adopted solid freeform fabrication method combined with surface modification which includes the hydrogel coating, therefore, inner or outer structure can be controlled and the property of anti adhesion can be improved.