• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.652-652
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• 2013

The conventional thermal chemical vapor deposition (CVD) setup for the graphene synthesis has mainly used convective heat transfer in order to heat a catalyst (e.g. Cu) up to $1,000^{\circ}C$. Although the conventional CVD has been so far widely accepted as the most appropriate candidate enabling mass-production of high-quality graphene, this method has stillremained under the standard for the commercialization largely due to the poor productivity arisen out of the required long processing time. Here, we introduced a fast and efficient synthetic route toward CVD-graphene. Unlike the conventional CVD using convection heat transfer, we adopted a CVD setup utilizing conduction heat transfer between Cu catalyst and rapid heating source. The high thermal conductive nature of Cu and the employed rapid heating source led to the remarkable reduction in processing timeas compared to the conventional convection based CVD (Fig. 1A), moreover, the synthesized graphene was turned out to have comparable quality to that synthesized by the conventional CVD (Fig. 1B). For the optimization of the conduction based CVD process, the parametric studies were thoroughly performed using through Raman spectroscopy and electrical sheet resistance measurement. Our approach is thought to be worth considerable in order to enhance productivity of the CVD graphene in the industry.

• 한국직업건강간호학회지
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• 제25권4호
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• pp.362-372
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• 2016

Purpose: This study intended to grasp real context of Cardiovascular disease (CVD)-related factors of Korean blue-collar workers, especially CVD-related knowledge, perception, beliefs, benefits and barriers of behaviors according to the health belief model. Methods: We interviewed twenty two workers working in two small-sized companies and performed two series of focus group interviews. Data were analyzed by deductive content analysis approach based on Elo & $Kyng{\ddot{a}}s$. Results: Excepting participants who have CVD risk factors, most participants had lower level of CVD risk perception. The level of CVD knowledge was low but there was difference by gender. CVD-related beliefs were 'fatal disease', 'caused by lifestyle' and 'difficult to prevent by themselves'. The risk reduction behaviors were motivated by current or family history of hypertension. But there were barriers to interfere practice of preventive behaviors such as poor quality of food provided by cafeteria in the workplace, frequent overtime, victim mentality as one of vulnerable social group, housework and financial burden, lack of facilities for rest and physical activity in the workplace. Conclusion: To develop intervention for reducing CVD risks in Korean blue-collar workers, we need to focus on improving CVD knowledge and perception and modifying work-related environments such as low quality of food and lack of facilities for rest and physical activity in the workplace.

• 한국전기전자재료학회논문지
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• 제32권3호
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• pp.192-195
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• 2019

Single-crystal diamond obtained by chemical vapor deposition (CVD) exhibits great potential for use in next-generation power devices. Low defect density is required for the use of such power devices in high-power operations; however, plastic deformation and lattice strain increase the dislocation density during diamond growth by CVD. Therefore, characterization of the dislocations in CVD diamond is essential to ensure the growth of high-quality diamond. In this work, we analyze the characteristics of the dislocations in CVD diamond through synchrotron white beam X-ray topography. In estimate, many threading edge dislocations and five mixed dislocations were identified over the whole surface.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.69-73
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• 1997

Microwave Plasma assisted CVD (Chemical Vapor Deposition) and DC Plasma CVD were used to prepare thin and thick diamond film, respectively. Diamond coated silicon nitride and fiee standing diamond thick film were eroded by silicon carbide particles. The velocity of the solid particle was about 220m/sec. Phase transformation and the other crack formation were investigated by using Raman spectroscopy and microscopy.

• 진공이야기
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• 제1권3호
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• pp.9-13
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• 2014

Vacuum growth of thin films via chemical vapor deposition (CVD) methods has been extensively used in modern semiconductor and flat panel display industries. The CVD processes have a wide range of variation and are categorized according to their working conditions, power sources, precursor materials, and so forth. Basic components and process steps common to all CVD branches are discussed. In addition, characteristics and applications of two major CVD techniques - LPCVD and PECVD - are reviewed briefly.

• 한국진공학회지
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• 제4권S1호
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• pp.102-107
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• 1995

We review the copper CVD line, via fill properties, and CMP line resistance. With CVD, trenches and vias with high aspect ratio(above 3) can be filled completely. Sputtering-reflow technique, a new method to filling copper into lines, is also reviewed to compare the CVD process.

• 대한간호학회지
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• 제45권6호
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• pp.857-867
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• 2015

Purpose: The purpose of this study was to investigate individual and organizational level of cardiovascular disease (CVD) risk factors associated with CVD risk in Korean blue-collar workers working in small sized companies. Methods: Self-report questionnaires and blood sampling for lipid and glucose were collected from 492 workers in 31 small sized companies in Korea. Multilevel modeling was conducted to estimate effects of related factors at the individual and organizational level. Results: Multilevel regression analysis showed that workers in the workplace having a cafeteria had 1.81 times higher CVD risk after adjusting for factors at the individual level (p =.022). The explanatory power of variables related to organizational level variances in CVD risk was 17.1%. Conclusion: The results of this study indicate that differences in the CVD risk were related to organizational factors. It is necessary to consider not only individual factors but also organizational factors when planning a CVD risk reduction program. The factors caused by having cafeteria in the workplace can be reduced by improvement in the CVD-related risk environment, therefore an organizational-level intervention approach should be available to reduce CVD risk of workers in small sized companies in Korea.

• 한국산업보건학회지
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• 제20권3호
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• pp.184-191
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• 2010

Although the usage of nanomaterials including carbon nanotubes (CNTs) has increased in various fields, scientific researches on workers' exposures and controls of these materials are very limited. The purpose of this study was to compare the airborne nanoparticles concentrations from two university laboratories conducting experiments of CNTs growth based on containment of thermal chemical vapor deposition (CVD). Airborne nanoparticle concentrations in three metrics (surface area concentration, particle number concentration, and mass concentrations) were measured by task using three direct reading instruments. In a laboratory where CVD was not contained, the surface area concentration, number concentration and mass(PM$_1$) concentration of airborne nanoparticles were 1.5 to 3.5 times higher than those in the other laboratory where CVD was confined. The ratio of PM$_1$ concentration to total suspended particles(TSP) in the laboratory where CVD was not confined was about 4 times higher than that in the other laboratory. This indicates that CVD is a major source of airbone nanoparticles in the CNTs growth laboratories. In conclusion, researchers performing CNTs growth experiments in these laboratories were exposed to airborne nanoparticles levels higher than background levels, and their exposures in a laboratory with the unconfined CVD were higher than those in the other laboratory with the confined CVD. It is recommended that in the CNTs growth laboratories adequate controls including containment of CVD be implemented for minimizing researchers' exposures to airborne nanoparticles.

• 사상체질의학회지
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• 제14권1호
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• pp.123-131
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• 2002

Glutathione S-transferase polymorphisms (GST) were examined in 98 cases with cerebrovascular disease (CVD) to test the hypothesis that GST polymorphisms confer a risk to an individual to develop CVD. Tobacco smoke is a major cause of both cancer and vascular disease. We therefore were stratified the subjects with CVD for smoking status, and then examined whether polymorphisms in this detoxification enzyme gene, GST, influence risk of CVD. Neither GSTM1 nor GSTT1 genotypes in the CVD group was significantly different from the control group (n=230), even in smokers. We attempted the combined analyses for GSTM1 and GSTT1 genotypes in CVD for smoking status. No significant association observed between the combined genotypes and CVD. We also classified the subjects and control group into four types according to Sasang Constitutional Medicine, Korean Traditional Oriental Medicine, and investigated the association among GST genotypes, CVD, and Sasang constitutional classification. Our observations do not confirm the effect of the GSTM1 and GSTT1 genotypes as a risk factor for CVD, even in smokers. Furthermore, we first attempted to evaluate the efficacy of Sasang Constitutional Medicine, and to find an association with CVD.

• Advances in Traditional Medicine
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• 제4권2호
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• pp.112-119
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• 2004

Glutathione S-transferase polymorphisms (GST) were examined in 98 cases with cerebrovascular disease (CVD) to test the hypothesis that GST polymorphisms confer a risk to an individual to develop CVD. Tobacco smoke is a major cause of both cancer and vascular disease. We therefore were stratified the subjects with CVD for smoking status, and then examined whether polymorphisms in this detoxification enzyme gene, GST, influence risk of CVD. Neither GSTM1 nor GSTT1 genotypes in the CVD group was significantly different from the control group (n=230), even in smokers. We attempted the combined analyses for GSTM1 and GSTT1 genotypes in CVD for smoking status. No significant association observed between the combined genotypes and CVD. We also classified the subjects and control group into four types according to Sasang Constitutional Medicine, Korean Traditional Oriental Medicine, and investigated the association among GST genotypes, CVD, and Sasang constitutional classification. Our observations do not confirm the effect of the GSTM1 and GSTT1 genotypes as a risk factor for CVD, even in smokers. Furthermore, we first attempted to evaluate the efficacy of Sasang Constitutional Medicine, and to find an association with CVD.