• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.591-594
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• 2003

기존 재료들의 단점인 재료의 전이성, 염증 유발, 효과의 단기 지속 등의 문제를 해결하기 위하여 PLGA 미립구를 주 재료로 하는 주사 충전재를 개발하였다. 생쥐 실험 결과 염증 반응이 적고 장기 이동성이 없으며 부피 유지 효과가 우수하다는 결론을 내렸으며 추가적으로 장기 추가 보완 실험을 실시하여 비뇨기과, 성형외과적 주사용 충전재로써의 적합성을 조사하겠다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.767-770
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• 2000

In order to reduce lean-time and cost, recently the technology of Rapid Prototyping and Manufacturing(PR/M) has been used widely. So various RP/M methods have been developed and these systems commercialized several years ago. The machining process is one of these methods. It also offers advantages such as precision and versatility. But there are some considerations during machining. The most important problem among them is the fixturing. So we have to overcome the limitation because the fixturing time is depend on the complexity of geometry to be machined. In this paper, we have developed the fixturing technique using filling process that can be widely useful for rapid products within a short time. So we have carried out some kinds of rapid products such as plastic knob and metal fan using our fixturing process. In fixturing step, the filling material might chosen a resin or a alloy according to wether the work material is plastic or metal respectively. Also we developed the set-up equipment attachable on the table of the milling machine that provided practicable quality during a series of machining operations, named by two step milling process.

• 대한기계학회논문집B
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• 제23권6호
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• pp.713-721
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• 1999

A composite plastic, where long metallic fibers are used as filling materials, is transformed from nonconducting to conducting medium as the volume fraction of filling metallic fibers is increased from zero : such drastic change in property is called the percolation. It is desired both for practical and theoretical purposes to understand the physics underlying the percolation and to estimate the percolation threshold that is defined by the minimum volume fraction of the metallic fibers for which the percolation occurs. In this study, percolation thresholds are calculated by Monte Carlo Computer simulation. Both lattice and continuum spaces are considered and detailed microstructures of metallic fibers are modelled as rigid and flexible bodies for both model spaces. Simulations are carried out for wide range of aspect ratios and discussions are given.

• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.309-313
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• 2014

The volume fraction of the coarse aggregate in the conventional plastic concrete is controlled relatively low to ensure a required workability. In this paper, a new type of coarse aggregate interlocking concrete with strength ranging from C30 to C80 was prepared with scattering-filling aggregate process. The strength of concrete prepared with this method increases obviously whereas the shrinkage decreases significantly, the cement dosage in the concrete decreased 20 % at the same time. The microhardness of the ITZ between the cement paste and scattering-filling aggregate is higher than that of the original aggregate, the ITZ become narrower and tighter also. The interlocking and more even distribution of the coarse aggregate and the water absorption of the addition of extra amount of coarse aggregates contribute to the strength and performance improvement of the concrete prepared with scattering-filling aggregate process.

• Restorative Dentistry and Endodontics
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• 제35권3호
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• pp.222-228
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• 2010

본 연구의 목적은 현재 치근단 역충전재로 널리 사용되고 있는 MTA와 새롭게 개발된 제품인 DB를 MG63 세포를 사용하여 비교하는 것이다. 치근단 역충전재료로는 MTA, DB, IRM을 사용하였고 대조군으로는 tissue culture plastic을 사용하였다. 각 재료를 혼합하고 혼합물의 경화가 일어나도록 24시간 동안 놓아두었다. MG63 세포를 각 군에 뿌려준 후 세포가 재료에 부착될 수 있도록 4시간 배양하였다. 치근단 역충전재를 세포에 접촉시킨 후 세포수준의 초기 반응을 관찰하였다. 12시간 더 배양한 후 세포가 각 재료에 붙어 있는 정도를 관찰하고, 각 재료가 골형성에 미치는 영향을 알아보기 위해 ELISA를 이용하여 $TGF{\beta}1$, OC를 측정하였고 ALP의 양도 측정하였다. 결과는 일원배치분산분석법으로 통계처리하였다. 그 결과, 재료에 부착이 일어난 세포의 수 항목과 OC 항목에서만 MTA와 DB간에 통계적으로 차이가 없었다. 다른 항목들에서는 모든 군 간에 통계적으로 유의한 차이가 있었다. DB가 MTA와 완전히 같은 세포반응을 보이지는 않았지만 부착이 일어난 세포의 수는 재료의 생체적합성을 나타내며 OC는 골형성 정도를 나타내므로 DB가 역충전 재료로 사용된다면 MTA와 유사한 결과를 보일 것으로 예측된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권3호
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• pp.236-241
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• 2010

Purpose: The purpose of this retrospective clinical study was to monitor the outcomes of periapical surgery in periapically infected tooth with or without retrograde filling materials (MTA or IRM). Patients and Methods: A total of 85 teeth in 63 patients were included in the study between November 2004 and August 2008. Randomly, MTA or IRM was used as a retrograde filling material or only apical resection without retrograde filling. Teeth with advanced periodontal bone loss or presence of root fracture were excluded from the study. The patients were subjected to a minimum follow-up period of 12 months, with a mean of 17.1 months. Results: Successful healing was observed in 83.3% of the MTA-treated teeth, 80% of the IRM-treated teeth and 75% of the teeth which was not retrograde filling. Doubtful healing was seen 9.3% (MTA), 13.3% (IRM), 12.5% (no retro-filling). The success rate of upper incisors (92%) was higher than lower lincisor and molars (66.7% and 50%, respectively). Conclusion: In this study, periapical surgery including retrograde filling improves the prognosis. And, no statistically significant differences were found between retrograde filling materials (MTA or IRM).

• Archives of Plastic Surgery
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• 제33권4호
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• pp.499-502
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• 2006

Purpose: Grave's disease is an autoimmune disease with chronic and systemic features. It affects the orbital fat and muscle bringing about defect in extrinsic eye motility, diplopia, optic nerve defect and lid retraction. In patients with lagopthalmos and resulting facial deformity, treatment can be done by rectus muscle recession or filling with various material. Autogenous auricular cartilage graft is often used and synthetic material such as synthetic acellular dermis, polyethylene meshs are also used for filling of the depressed area. Nevertheless, autogenous auricular cartilage grafts are difficult to utilize and synthetic materials sometimes result in protrusion or infection. Therefore, hard palate mucosa was considered as an alternative. We report two cases of patients with lower eyelid retraction corrected with autogenous hard palate mucosa. Methods: We performed this operation in two patients of Graves' ophthalmopathy. The capsulopalpebral fascia was incised and elevated through an incision on the conjunctiva. Then, the harvested hard palate mucosa was sutured to the inferior border of the tarsus and covered with the conjunctiva. Results: The lower eyelid retraction was corrected successfully. No hypertrophy or deformation of the transplanted hard palate mucosa was noted 6 months after the surgery. Conclusions: From the results above, we may conclude that the hard palate mucosa serves as an ideal spacer for the curvature and the inner lining in lower lid retraction. Hard palate mucosa is as sturdy as the autogenous cartilage but is much easier to utilize. It can be also used for lid retraction after lower lid aesthetic surgeries or traumas.

• 한국기계가공학회지
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• 제3권4호
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• pp.95-100
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• 2004

Plastics is used to produce precise parts with an inclusion of a reinforcement material such as glass fiber or carbon fiber to improve the dimension accuracy. The plastic goods can be produced with inaccurate dimensions, low mechanical strength, or residual stress due to the over packing of cavity inside, if the filling balance of melt resin is not accomplished. To overcome this problem, it is necessary to design the runner system with the geometrical balance at the mold design stage. However, even if the balanced runner system is achieved, a severe filling imbalance is observed practically in a multi-cavity mold. In this study, experiments were performed with Taguchi method to achieve the filling balance in multi-cavity mold with a symmetric runner system, by the use of pure PA and PA with glass fiber 33%. The experimental results were investigated to understand the effect of related molding factors on the filling imbalance for two resins.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제16권2호
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• pp.130-136
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• 1994

Toothash and plaster of Paris (Calcium sulfate) have been studied for bone substitute through experimental studies and clinical studies. Toothash is like resorbable hydroxyapatite. Plaster of Paris is resorbable and biocompatible. The toothash combined with plaster of Paris has the advantages of individual characteristics. The authors used this composite material in the jaw defect filling. In operation, we could manage this implant material easily and remove the dead space. During the followup period, this composite material was resorbed gradually and substituted as new-forming bone from the surrounding tissue. Complications were minor and treated completely without problems.

• 소성∙가공
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• 제17권7호
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.