• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.10-18
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• 2004

It is well known that the stratified charge combustion has many kind of advantages to combustion characteristics, such as higher thermal efficiency and less CO, NOx levels than conventional homogeneous mixture combustion. Although this combustion can be caused low fuel consumption, it is produced the high unburned hydrocarbon and soot levels because of different equivalence ratio in the combustion chamber. Moreover it has a lot of possibility of low output and misfire if the mixture gas would not be in existence around the spark plug. In this paper, fundamental studies for stratified combustion were carried out using a constant volume combustion chamber. The effect of locally mixture gas distribution according to control the direct injection and premixed injection in the chamber were examined experimentally. In addition, the effects of turbulence on stratified charge combustion process were observed by schlieren photography.

• Journal of the Korean Professional Engineers Association
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• v.43 no.1
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• pp.26-31
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• 2010

The changes of climate and earth environment caused by Global Warming has seriously occurred recently. For instance, the water in the Chad Lake in Africa has continuously disappeared and Tuvalu in the South Pacific is facing a serious natural disaster with that the entire country is sinking under the sea. These natural disasters become a serious risk threatening the existence of the human-race. Therefore, we needs a fundamental measure to prevent Global Warming. That is a natural phenomenon that makes the earth warmer by 6 types a greenhouse gas including $CO_2So$ we look for an answer from the 'Green Growth' movement.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.938-940
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• 1998

In order to improve insulating character and ability of insulating system of power apparatus, the interfacial and complex structure is widely used. However, the interface or complex structure of insulation materials is reported as a weak point which causes breakdown. As the interface of insulation system degrades its electrical property and eventually causes a failure, the datailed phenomenon analysis is reported. The object of this paper is to evaluate dielectric property of PET film with the interface. The $tan{\delta}$ increased with the existence of semiconducting layer and showed prominent decrease as a function of temperature. Also, the $tan{\delta}$ showed prominent increase as a function of frequency. The dielectric properties of interfacial were affected by the interface characteristics.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.255-255
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• 2006

Polymeric nanoparticles are recognized as promising drug carriers [1]. Here, novel tri-block copolymers based on poly PPDO, PCL and PEG were synthesized and employed for the formulation of reproducible polymeric nanoparticles [2]. To estimate the feasibility of the polymer to form polymeric nanoparticles, nanoparticles were prepared by co-solvent evaporation technique. Polymerization and structural features of the polymer were analyzed by different physico-chemical techniques. Existence of hydrophobic domains as a core of nanoparticles was characterized by $^{1}H-NMR$ spectroscopy, and further confirmed by fluorescence technique using pyrene as probe.

• Journal of Technology Innovation
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• v.11 no.2
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• pp.175-193
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• 2003

The purpose of this study is to examine relationship between public R&D investment and private R&D investment in Korea, and to obtain policy implications of the results. To this end, the author attempts to provide more careful consideration of the causality issues by applying rigorous techniques of Granger causality. Tests for unit roots, co-integration, and Granger causality based on an error-correction model are presented. The existence of bi-directional causality between public R&D investment and private R&D investment is detected. This finding has various implications for policy analysts and forecasters. Increasing private R&D investment requires enormous public R&D investment, though there are many other factors contributing to private R&D investment, and public R&D investment is but one part of it. Thus, this study generates confidence in decisions to invest in public R&D. Moreover, this study lends support to the argument that increase in private R&D investment, ceteris paribus, gives rise to public R&D investment. Increase in private R&D investment results in greater national income to be spent on R&D investment and stimulates further public R&D investment.

• Korean Journal of Child Studies
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• v.25 no.4
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• pp.71-92
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• 2004

The purpose of this ethnographic study was to observe and understand interactions of toddlers and teachers in context. Specific questions were "What are the motives and features of the interactions between toddlers and teacher?" Subjects were twenty 2-year-old daycare children and their teachers. Methods covered 11 weeks of interviews and participatory observation. The major findings were that the interactions between toddlers and teachers was mainly initiated by toddlers and consist of physiological and emotional needs, conflict mediation and participation in play. As toddler get to the age of self-recognition but still need adult's assistance, the co-existence of dependence and independence was evident. Children used a variety of verbal and non-verbal signals with both positive and non-positive overtons.

• Archives of Craniofacial Surgery
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• v.21 no.4
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• pp.257-260
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• 2020

The concurrence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in a single tumor is rarely encountered. We report a case of BCC and SCC in a single tumor in the anterior auricular area. A 70-year-old woman had been diagnosed with BCC by a punch biopsy performed at a dermatology clinic. We performed wide excision of the tumor with an ulcer in the anterior auricular area. Analysis of the biopsy specimen revealed the presence of both BCC and SCC in the tumor. This case illustrates that it is necessary to establish a precise diagnosis and formulate appropriate surgical and treatment plans considering the possibility that two carcinomas may coexist, although the possibility is low in patients with skin cancer.

• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1513-1520
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• 1994

Mechanical properties of hot-pressed SiC whisker/Al2O3 composites were strongly dependent on the granular characteristics of mixed powder, which were controlled by co-dispersion condition, the existence of steric barrier on whisker surface, and granulating method, etc. Heat-treatment of SiC whiskers at $700^{\circ}C$ for 1 hr in air was very effective both for achieving dispersion stability of whiskers with PVA adsorption and for obtaining excellent mechanical properties of resulting composites. It is believed from the fractography of composites prepared with various whisker dispersion conditions that the most common fracture origin of Al2O3 agglomerate could be attributed to whisker clusters arising due to flocculation. Further improvement of mechanical properties of composites were achieved by hot pressing green tapes prepared by Doctor-blade process, which promoted two-dimensional random alignment of whiskers.

• Journal of Gastric Cancer
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• v.11 no.2
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• pp.126-130
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• 2011

A composite glandular/exocrine-endocrine carcinoma of the gastrointestinal tract is characterized by the co-existence of two adjacent, but histologically-distinct tumors in an organ. Composite glandular/exocrine-endocrine carcinomas are a special type of tumor comprised of common adenocarcinomas and neuroendocrine components that account for at least one-third of the entire tumor area. Composite tumors have been reported in a range of organs, but are relatively rare in the stomach. We report a case of a composite neuroendocrine carcinoma with an adenocarcinoma of the stomach (mixed exocrine-endocrine carcinoma), which was misdiagnosed as a giant submucosal tumor preoperatively based on esophagogastroduodenoscopy and a contrast-enhanced axial computed tomographic scan.

• Child Studies in Asia-Pacific Contexts
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• v.4 no.2
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• pp.127-136
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• 2014

The number of multicultural families with children are growing in South Korea. When it comes to childrearing, co-existence of two different cultures in these families pose unique challenges as husbands and wives navigate differences in norms and practices. The goal of this study was to examine what predicts involvement in child care among South Korean fathers in multicultural families. We hypothesized that the degree of wives' adaptation to South Korea and husbands' cultural characteristics, such as family ideology and cultural competence, would influence father involvement in child care. The sample consisted of 138 Korean fathers and their wives from China. Participants completed a questionnaire. Results showed that South Korean fathers engaged in a moderate level of child care activities. As hypothesized, their Chinese wives' level of adaptation to South Korea and their own cultural characteristics were significantly associated with their involvement in child care. South Korean fathers were more likely to get involved in child care when their wives were less acculturated. Also, culturally considerate and less traditional men in terms of family ideology were more likely to perform child care.