• 에너지공학
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• 제20권4호
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• pp.286-291
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• 2011

하이브리드 자동차는 전기방식 회생제동을 이용하여 연비가 우수하다. 본 논문에서는 새로운 공압식 회생제동 장치를 소개하였다. 공압식 회생제동장치는 압축과 팽창기능을 동시에 가지는 스크롤 기구를 이용한다. 차량 감속시에는 스크롤 기기는 압축기로 작동되면서 대기중의 공기를 압축하여 압축탱크에 저장한 후 차량 가속시에는 스크롤기구가 팽창기로 작동되면서 탱크에 저장된 압축공기가 차량 운동에너지로 활용된다. 회생제동장치를 사용함으로써 개선되는 연비를 분석하기 위해, CVS-75 모드 주행조건에서 시뮬레이션을 수행하였다.

• 소성∙가공
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• 제19권6호
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• pp.337-343
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• 2010

Current need of weight reduction in automotive part increases the application for high strength steel (HSS). The various types of high strength steels have been used to produce chassis part, control arms and trailing arms for weight reduction and increasing of fatigue durability such as dual phase steel (DP) and ferrite bainite steel (FB). But, DP and FB steels have proven to show inferiority in durability as well as press formability. Edge cracking occurred often in flange forming and hole expansion processes is the major failure encountered. This paper discussed the behavior of edge stretchability of high strength steel of DP and FB steels. Experimental works have been conducted to study the effect of punch clearance and burr direction on hole expansion ratio (HER). Also finite element simulation (FEM) has been preformed to clarify the mechanism of flange crack and support the experimental results on HER of DP and FB steels. It was simulated the whole process of blanking process following by hole expansion process and ductile fracture criterion named the modified Cockcroft-Latham model which was used to capture the fracture initiation. From the hole expansion tests and FEM simulation studies it was concluded that ferrite bainite steel showed better stretch-flangeability than dual phase steel. It was attributed to the lower work hardening rate of ferrite bainite steel than dual phase steel at the sheared edge.

• Composites Research
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• 제27권2호
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• pp.52-58
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• 2014

사출 성형을 통해 제조된 단섬유 강화 복합재는 사출 성형 중 발생하는 수지 유동으로 인해 동일 시편 내에서도 다양한 섬유 배향을 갖는다. 이러한 섬유의 배향은 최종 복합재의 기계적, 열적 특성에 많은 영향을 주므로, 본 연구에서는 사출 성형된 탄소단섬유 강화 PA6/PPO 복합재의 섬유 배향을 광학 현미경 분석을 통하여 측정하고 섬유의 배향이 복합재의 충격강도 및 열팽창 계수에 미치는 영향을 분석하였다. 충격강도의 경우에 섬유의 배향이 크랙이 전파되는 방향에 수직으로 배향되어 있을수록 더 높은 충격강도를 보였으며, 이는 섬유의 배향에 따른 충격내성 강화 메커니즘과 밀접한 연관성을 보여주었다. 열팽창 계수의 경우에는 섬유가 열팽창률을 측정하는 방향과 동일한 방향으로 배향되어 있을수록 더 낮은 열팽창계수를 보였으며, 이 결과 역시 섬유의 배향이 열팽창 특성에 미치는 메커니즘과 밀접한 연관성을 보였다.

• 한국시스템다이내믹스연구
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• 제11권2호
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• pp.77-102
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• 2010

This paper examines a mechanism of the Electronic Territory Expansion and the Information-oriented Society. Especially, a strategy for the territory development based on intelligence is suggested. The strategy is divided into a strategy for the domestic electronic territory and a plan for the global electronic territory. To examine the strategy and the plan, this paper is using the causal map analysis based on the System Thinking Approach. The causal map of the mechanism is characterized by a positive feedback loop. The paper has concluded that it is important to make the positive loops as a virtuous circle. It means that when a society dominates the advantageous position firstly in the field of intelligent and electronic territory, the competitiveness can grow in arithmetical progression.

• International Journal of Contents
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• 제8권1호
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• pp.10-15
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• 2012

Since MegaStudy started e-learning business for Korean high school students, the Korean e-learning industry began to expand and steadily gain attention. This paper focused on the analysis of the development of the Korean e-learning business for teens and the growth of MegaStudy. The three institutional mechanisms were used to examine the factors that aided the development of the business. The regulatory mechanism was the government policy to prevent the expansion of the offline private education sector, which greatly aided the growth of the e-learning business. The mimetic mechanism was the notion to mimic the characteristics of the Korean e-business initiatives. The normative mechanism involved the widespread social norm suggesting that every student should be given an equal opportunity of private education. This paper also examined the case of MegaStudy as a successful case of the e-learning companies. It analyzed the business model of MegaStudy, which is based on its advantage as the front-runner and its high-quality contents and services.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 추계 총회 및 학술발표회
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• pp.43-44
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• 1995

The diffusion behavior of liquid into polymer has been described by Fick's law, but the departure from Fickian diffusion is frequently found. In this study, 'noble' expressions for the rates of relaxation and sorption are introduced to eliminate these limitations. The ralaxation-sorption coupled mechanism model are based on the possibility of contacting liquid molecule and the active site which has the numerical concept of free volume. The concept has an analogy of reaction rate expressed by the possibility of collision with molecules and used in adsorption and reactive extraction etc. The new model simulated by Rungc-Kutta method for initial-value problem and Fickian diffusion is caompared with experimental data. The results show that the ralaxation-sorption coupled mechanism is able to account well for Fickian and non-Fickian sorption behavior including sigmoid and two-stage. In addition, this model has a chance of expansion to multi-component sorption with ease.

• Journal of Welding and Joining
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• 제32권1호
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• pp.40-46
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• 2014

Bonding technology and bonding mechanism of metal to ceramic including brazing, diffusion bonding, friction welding and etc were reviewed in this study. Various factors should be considered from a bonding design step to acquire a good bonding joint because of a large difference between metal and ceramic in crystal lattice, coefficient of thermal expansion and various properties. In addition, metal and ceramic bonding technologies are constantly being developed according to precise components, multi-function and application to harsh environment. However, improvement of bonding properties and bonding reliability also should be accompanied. Bonding of ceramics, such as $ZrO_2$, $Ti_3AlC_2$ and SiC, to metals like Ti-alloy, TiAl and steel were described in this paper.

• 대한치과교정학회지
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• 제15권2호
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• pp.353-368
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• 1985

This present paper describes 3 clinical cases which were treated with Bioprogressive mechanism. Each patient has shown a deficient maxilla combined with prognathic and steep mandible. The purpose of treatment was planned to obtain the forward growth of maxilla and redirectioning of mandibular growth. The most noteworthy approach in the treatment was the application of Cl III intermaxillary elastics with upper protraction utility arch immediately after rapid maxillary expansion. In the analysis of the data obtained from pre- and post treatment lateral cephalogram, the result achieved by this method is very favolable to the correction of anteroposterior relationship of maxilla and mandible.

• 유통과학연구
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• 제18권5호
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• pp.99-109
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• 2020

Purpose: This study aims to develop and empirically analyze a research model in order to comprehend the relationship among the service quality of market-wholesaler system, re-transaction intention, and recommendation intention of forwarder. Further, we suggest new six factors reflecting the service quality of market-wholesaler system and highlight market expansion of forwarder as a mechanism in the relationship. Research design, data and methodology: The authors developed the new scales measuring the service quality of market-wholesaler system (i.e. trade price, price fluctuation, payment receipt, settlement period, trade information, and customer service) and conducted a cross-sectional survey for 439 forwarders in a wholesale market. And then we performed a series of path analyses to test hypotheses. The hypotheses are as follows. [H1] The service quality of market-wholesaler system will positively affect forwarders' market expansion, [H2] Forwarders' market expansion will positively affect their re-transaction intention, [H3] Forwarders' market expansion will positively affect their recommendation intention, [H4] Forwarders' re-transaction intention will positively affect their recommendation intention. Results: The results showed that all the six factors for the service quality of market-wholesaler system were positively related to market expansion of forwarders. There was a differential effectiveness in the six factors of the service quality. More specifically, the positive effect of customer service factor was the strongest on market expansion of forwarders. And the respective effects of trade price, price fluctuation, settlement period, trade information factors were followed in order. The positive effect of payment receipt factor was the weakest on market expansion of forwarders. Also, market expansion of forwarders was positively related to their re-transaction intention and recommendation intention. Furthermore, market expansion of forwarders was indirectly related to recommendation intention through re-transaction intention as well. Conclusions: The research findings provide important theoretical and practical implications. This study is the first to attempt to test the perception of forwarders for the service quality of market-wholesaler system by developing and using the new scales. Also, there has been a sharp controversy about the effectiveness of market-wholesaler system. The findings support that market-wholesaler system would be activated by empirically verifying the effectiveness of the service quality on the various outcomes.

• 대한치과기공학회지
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• 제23권2호
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• pp.179-188
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• 2002

With regard to the manufacture of dental prosthesis, all the dental mechanism is of vital significance at the aspect of activating its function by fixing the prosthesis to Patient's oral cavity. However, if there we will take our immediate action without the discretion about its process none the less for the importance of dental mechanism, then we might have a serious problem. Accordingly, there need to pay attention to the dilatability makes up for the shrinkage state occurring by the feature of metal materials and manufacturing process which appeared in the process of dental mechanism, which eventually is expected to playa very important role in casting a dental prosthesis appropriate to one's oral tissue. This study was designed to take into account of the effects on margin consistency of prosthesis according to the continued time of casting-ring in the course of the casting of dental alloy. For this, the researcher made an experiment on the casting of dental alloy, its dilatability, and the change of phase. The results of this study were as follows: First, the researcher could see that the sample which was cast under the condition of $650^{\circ}C/20$ Minutes(the continued time) was far superior to others at the aspect of margin consistency. Second, according to the measurement of expansion coefficient by Dilatometer, the researcher perceived the fact that the expansion-coefficient showed a maximum of $37.1{\mu}m$ considering the sample's length which was cast with ordinary temperature under the condition of $650^{\circ}C/20$ Minutes. Third, from the result of X-ray diffraction under the condition of $650^{\circ}C/20$ Minutes(the continued time), the researcher could find that there's no difference between the change of phase and its intensity. As mentioned above, the researcher could ascertain the fact that its contraction don't give rise to the change of phase.