• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.861-862
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• 2009

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.339-347
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• 2006

Oral leukoplakia is the most common premalignant lesion and malignant transformation has been reported from verrucal lekoplakia. Homogenous, benign leukoplakia develops into a line of squamous cell carcinoma such as verrrucous carcinoma, papillary squamous cell carcinoma and invasive squamous cell carcinoma. Early diagnosis and intervention of premalignant leukoplakia is up-most important to prevent transformation into a oral squamous cell carcinoma. Any change in surface, size and color warrants repeated biopsy. If verrucous carcinoma is evidently derived from the previous leukoplakia, wide surgical excision and periodic follow up is needed. Surgically removed lesion of leukoplakia has the tendency to recur. Follow-up is very important to patient and clinician. Although many therapies have been reported to oral leukoplakia and verrucal carcinoma, accepted treatment principle is not exist so far. But surgical removal is recommended as the treatment of choice.

• 대한기계학회논문집
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• 제14권2호
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• pp.367-375
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• 1990

A data structure representing 3-D objects was designed for the personal computer. It is very simple to be used in the personal computers which have small memory and low speed. A homogeneous transformation for developing 3-D objects was derived. Each developing procedure consists of five transformations : one translational-three rotational-one translational. Developing a solid is a creative work. So the results of developing vary with the order of surfaces to be developed. One method to reduce the length of seam was considered. The programs used in this study were written in Pascal and Assembly and a modeller that generates 3-D primitives was included. This program is an interactive dual-screen system. While all the menus in Korean are displayed at the monochrome monitor, the development figures with projective views are drawn at the color monitor. The program has wide applications for plate works.

• Applied Microscopy
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• 제45권2호
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• pp.52-57
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• 2015

Bulk metallic glass (BMG) shows higth strength, high elastic limit, corrosion resistance and good wear resistance and soft magnetic properties and has been considering as a candidate for new structural materials. But they show limited macroscopic plasticity and lack of tensile ductility due to highly localized shear deformation, which should be solved for real structural application. In this paper researches on the enhancement of plasticity of BMG were reviewed briefly. Introducing heterogeneous structure in glass is effective to induce more shear transformation zones (STZs) active for multiple shear band initiation and also to block the propagating shear band. Several methods such as BMG alloy design for high Poisson's ratio, addition of alloying element having positive heat of mixing, pre-straining BMG and variety of BMG composites have been developed for homogenous distribution of locally weak region, where local strain can be initiated. Therefore enhancement of plasticity of BMG is normally accompanied with some penalty of strength loss.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.403-408
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• 2012

In this study, the homogenous Pd nanoparticles (Pd NPs) were first prepared with bayberry tannin (BT) as the stabilizers. Subsequently, the obtained bayberry tannin-stabilized Pd nanoparticles (BT-Pd) were immobilized onto ${\gamma}-Al_2O_3$ to prepare heterogeneous ${\gamma}-Al_2O_3$-BT-Pd catalysts. Fourier Transformation Infrared Spectrum (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed that the Pd NPs were well stabilized by the phenolic hydroxyl groups of BT. Transmission Electron Microscopy (TEM) observation indicated that the diameter of the Pd NPs can be effectively controlled in the range of 4.2-16.0 nm by varying the amount of BT. It is found that the ${\gamma}-Al_2O_3$-BT-Pd catalysts exhibit highly activity for various olefin hydrogenations. For example, the initial TOF (turnover frequency) of the ${\gamma}-Al_2O_3$-BT-Pd in the allyl alcohol hydrogenation is as high as $12804 mol{\cdot}mol^{-1}{\cdot}h^{-1}$. Furthermore, the ${\gamma}-Al_2O_3$-BT-Pd can be reused 5 times without significant loss of activity, exhibiting a superior reusability as compared with conventionally prepared ${\gamma}-Al_2O_3$-Pd catalysts.

• 한국콘텐츠학회논문지
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• 제14권8호
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• pp.40-49
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• 2014

전지구화는 국제사회의 인구 이동을 더욱 가속화시켰으며, 한국도 이러한 변화로부터 예외가 될 수는 없었다. 한국은 국가의 경제 성장 및 발전을 위해 역사적으로 해외에 노동력을 수출한 경험이 있다. 그러나 1990년대 말부터 이러한 사회적 흐름이 바뀌었고, 국내에 거주하는 이주민의 수가 급증하였으며, 단일민족국가로서의 특징이 점차 변화하였다. 그러나 대중 매체를 통해 비춰지는 소수민족집단의 모습이 한국사회에 어떠한 문화적 및 정치적인 영향력을 행사하고 있는지 살펴볼 필요가 있음에도 불구하고 이에 대한 연구는 현저히 적은 것으로 나타났다. 따라서 본 연구는 한국공영방송에 비춰지는 소수민족집단에 초점을 맞추어 실증적 분석을 통해 한국사회의 시대적 변화 속에서 공영방송이 인종적 소수자들을 구체적으로 어떻게 보도하는가를 밝히고자 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.199-199
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• 2011

The addition of a carbanion to ${\yen}{\acute{a}}{\yen}{\hat{a}}$-unsaturated carbonyl compounds is of importance in the C-C bond formation reactions for modern pharmaceuticals and organic synthesis. Recently, heterogeneous asymmetric catalysis became more attractive area of research because of the easy recovery and separation of the catalyst from the reaction system. Most of synthetic methods for heterogeneous catalysts were grafting or immobilization of homogeneous catalyst onto the solid supports. Trans-1,2-Diaminocyclohexane(DACH) and L-proline ligands have been enormously used as chiral ligands in several catalytic transformation under homogenous conditions. Our group prepared l-proline functionalized mesoporous silica was synthesized under acidic condition using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer template (EO20PO70EO20, Pluronic P-123, BASF). Furthermore, we successfully directly synthesized trans-1,2 diaminocyclohexane functionalized mesoporous silica by using microwave method. The direct functionalization of chiral ligand into the framework of mesoporous materials is expected to be useful for the heterogeneous asymmetric catalysis. So, we adopt the direct synthesis of chiral ligand functionalized mesoporous silica by using thermal and microwave irradiation. Then, chiral ligand functionalized mesoporous silicas were applied to enantioselective asymmetric catalytic reactions.