• 대한인간공학회지
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• 제33권4호
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• pp.289-297
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• 2014

Objective: The purpose of this study is to identify the incidence risk of cardiovascular disease (CVD) in the workplace, and to suggest the prediction models for level of CVD incidence risk. Background: CVD can be caused by various factors related to personal habits such as diet and exercise, or genetics. However it can also be caused and aggravated by work, making the elimination of such risk factors at work crucial disease (KOSHA, 2013). Method: The distribution of CVD risk assessment levels of 162 workers was compared with the acquired medical examination data to discuss the necessity of assigning additional risk factors. Two alternative risk assessment models were given to enhance the accuracy of the evaluation; adjusting risk scores given in the KOSHA GUIDE H-1-2013 (alternative 1) and building a matrix of KOSHA GUIDE H-1-2013 and risk assessment results based on work condition levels (alternative 2). To verify the suggested models, medical examination results of 12 workers approved of convalescence were referred to. Results: The second alternative showed more relevance between the results and workers approved of convalescence in predicting the risk group when applied to actual heath examination data from the approved workers. The power of description of the new method for determining the risk of CVD incidence, 83.3%, is higher than that of KOSHA GUIDE H-1-2013, 25%. Conclusion: Results of this study imply that more approved workers had been from unmanaged normal groups than managed risk groups, raising the importance of CVD management. Application: The new prediction model considering working time and shift work developed in this study is expected to be a fundamental data for risk analysis and management of CVD in the workplace.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.857-864
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• 2018

현대인의 눈높이에 맞는 친환경적인 고급품질의 인조진주 제품개발이 세계의 악세사리 및 생활용품 시장에서 요구되고 있다. 본 연구는 고품질의 인조진주 제품을 경제적으로 대량생산하기 위한 방법으로 유기안료를 인조진주 제조용 친환경 무기안료로 대체하고 기존 제조 방식에서 사용하는 주재료였던 니트로셀룰로오스를 우레탄 바인더로 대체하여 광택도가 73.4%에서 86.7%로 증가하였으며 CVD 마감처리 후에는 96%의 높은 광택도를 가졌다. 색차분석 결과 CVD 코팅으로 인하여 빛의 간섭효과 때문에 a*와 b*값이 각각 +37.7에서 +31.9로, +24.5에서 +14.2로 감소하면서 다양한 색을 발현하여 영롱한 빛깔의 인조진주가 제조되었다. 마감 증착된 고품질의 인조진주의 내화학성, 광택도, 색차계, 표면 거칠기, 내마모성, 중금속함량검사, 염수분무테스트 등을 분석하여 품질향상 및 인체 무해성을 확인하였다.

• The Korean Journal of Ceramics
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• 제2권4호
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• pp.184-187
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• 1996

Diamod nucleation by mw assisted CVD was examined various conditions namely, (1) diamond nucleation on variour substrate materials, such as Si, cubic BN, pyrolytic BN and AIN, (2) AST(Activated species transport) method which promote nucleation of diamond on single crystal and polycrystalline alumina substrate was developed. (3) Effect of bias enhancement of nucleation on single crystalline Si was examined, and finally (4) DST (Double step treatment) method was developed to enhance diamond nucleation on Ni. In this method, we separated carbon diffusing process into Ni, carbon precipitating process from the inside of Ni and diamond precipitation process.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.383-383
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• 2009

Silicon is commercially prepared by the reaction of high-purity silica with wood, charcoal, and coal, in an electric arc furnace using carbon electrodes, so called the metallurgical refining process, which produces ~98% pure Si (MG-Si). This can be further purified to solar grade silicon (SoG-Si) by various techniques. The most problematic impurity elements are B and P because of their high segregation coefficients. In this study, we explored the possibility of the using Cat-CVD for Si purification. The existing hot-wire CVD was modified to accommodate the catalyzer and the heating source. Mo boat (1.5 cm ${\times}$ 1 cm ${\times}$ 0.2 cm) was used as a heating source. Commercially available Si was purchased from Nilaco corporation (~99% pure). This powder was kept in the Mo-boat and heated to the purification temperature. In addition to the purification by cat-CVD technique, other methods such as thermal CVD, plasma enhanced CVD, vacuum annealing was also tried. It is found that the impurities are reduced to a great extent when treated with cat-CVD method.

• 한국재료학회지
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• 제15권4호
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• pp.246-251
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• 2005

Plasma enhanced chemical vapor deposition(PE-CVD) method has an advantage in synthesizing carbon nanotubes(CNTs) at lower temperature compared with thermal enhanced chemical vapor deposition(TE-CVD) method. In this study, CNTs was prepared by using PE-CVD method. The growth rate of CNT was faster more than 100 times on using Invar alloy than iron as catalyst. It was found that chrome silicide was formed at the interface between chrome layer and silicon substrate which should be considered in designing process. Nanoparticles of Invar catalyst were found oxidized on their surfaces with a depth of 10 m. Microstructure was analyzed by scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive x-ray spectrometry. Based on the result of analysis, growth mechanism at an initial stage was suggested.

• 반도체디스플레이기술학회지
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• 제19권1호
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• pp.67-72
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• 2020

This study analyzes the method of adhesion and improvement between heat.er and RF filter in PE-CVD equipment through TRIZ method and proposes a solution. TRIZ Solution such as function analysis, 9-window matrix, ASIT, and Root cause analysis were used. The contact temperature between the heater and the RF filter was 20% and the surface temperature was lowered to 5.7℃, suggesting an improvement method for the thermal expansion of the PE-CVD equipment hot zone.

• 반도체디스플레이기술학회지
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• 제3권3호
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• pp.45-50
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• 2004

Highly oriented diamond (HOD) films in polycrystalline can be grown on the (100) silicon substrate by microwave plasma CVD. Bias enhanced nucleation (BEN) method was adopted for highly oriented diamond deposition with high nucleation density and uniformity. The substrate was biased up to -250[Vdc] and bias time required for forming a diamond film was varied up to 25 minutes. Diamond was deposited by using $\textrm{CH}_4$/CO and $H_2$ mixture gases by microwave plasma CVD. Nucleation density and degree of orientation of the diamond films were studied by SEM. Thermal conductivity of the diamond films was ∼5.27[W/cm.K] measured by $3\omega$ method.

• 한국표면공학회지
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• 제48권3호
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• pp.126-130
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• 2015

A high-pressure depletion method using plasma chemical vapor deposition (CVD) is often used to deposit hydrogenated microcrystalline silicon (${\mu}c-Si:H$) films of a low defect density at a high deposition rate. To understand proper deposition conditions of ${\mu}c-Si:H$ films for a high-pressure depletion method, Si films were deposited in a combinatorial way using a multi-hollow discharge plasma CVD method. In this paper the substrate temperature dependence of ${\mu}c-Si:H$ film properties are demonstrated. The higher substrate temperature brings about the higher deposition rate, and the process window of device quality ${\mu}c-Si:H$ films becomes wider until $200^{\circ}C$. This is attributed to competitive reactions between Si etching by H atoms and Si deposition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.264.1-264.1
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• 2013

Graphene is a two-dimensional carbon material whose structure is one-atom-thick planar sheet of sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice. It has drawn significant attention with its distinguished structural and electrical properties. Extremely high mobility and a tunable band gap make graphene potentially useful for innovative approaches to electronics. Although mechanical exfoliation of graphite and decomposition of SiC surfaces upon thermal treatment have been the main method for graphene, they have some limitations in quality and scalability of as-produced graphene films. Solutionphase and solvothermal syntheses of graphene achieved a major improvement for processing, however for device fabrication, a reproducible method such as chemical vapor deposition (CVD) growth yielding high quality films of controlled thickness is required. In this research, we synthesized hexagonal graphene flakes on Cu foils by CVD method and controlled its coverage, density and the size of graphene domains by changing reaction parameters. It is important to control these parameters of graphene growth during synthesis in order to achieve tunable properties and optimized device performance.

• 멤브레인
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• 제14권3호
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• pp.201-206
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• 2004

열화학적 IS 공정에서 요오드화수소의 분해에 적용하기 위하여 화학증착법(CVD)으로 제조된 silica 막의 안정성을 HI-$H_2O$ 기상 혼합물에서 평가하였다. Si 원천으로 tetraethoxysilane을 사용하여 서로 다른 CVD 온도로 기공크기가 100 nm인 $\alpha$-alumina를 처리하였다. CVD온도는 $700^{\circ}C$, $650^{\circ}C$, $600^{\circ}C$이었다. $600^{\circ}C$에서 수행한 단일 성분의 투과 실험에서 측정한 막의 $H_2$/$N_2$ 선택도는 CVD 온도 $700^{\circ}C$의 M1 막은 43.2, $650^{\circ}C$의 M2 막은 12.6, $600^{\circ}C$의 M3 막은 8.7을 나타내었다. HI-$H_2O$ 기상 혼합물에서 안정성 실험은 $450^{\circ}C$에서 수행하였는데, CVD 온도 $650^{\circ}C$에서 처리된 막이 다른 온도에서 처리된 막보다 더 안정성이 더 좋은 결과를 얻었다.