• 한국세라믹학회지
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• 제43권10호
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• pp.607-612
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• 2006

In VARTM (Vacuum Assisted Resin Transfer Molding) process, the permeability generally controls the filling time of the resin and it also affects the void characteristics of the fiber composite. In this study, carbon and glass fiber inter-layered hybrid composites (carbon fiber centered stack) with an epoxy matrix were fabricated by VARTM process and evaluated the resin flow and macro void characteristics. The permeability of glass fiber was higher than that of carbon fiber used in this study. Using Darcy's equation, the permeability of hybrid composites could be predicted and experimentally confirmed. After curing, the macro void content of hybrid composites was investigated using image analyzer. The calculated filling time was well agreed with experimental result and the void content was significantly changed in hybrid composites.

• Geomechanics and Engineering
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• 제29권3호
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• pp.349-357
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• 2022

Abnormal climate events are occurring frequently around the world. In particular, cold waves and heavy snow lead to damage and deterioration of facilities, which can cause loss of life or property damage, such as shortening the lifespan of facilities. Therefore, it is very important to prepare an appropriate maintenance system and to establish a strategy to cope with abnormal weather conditions. In this study, laboratory freezing experiments were performed to analyze the freeze-thaw characteristics affecting the tunnel concrete lining, and heat flow analysis was carried out based on the test results. Based on these experimental and theoretical analysis results, quantitative freeze-thaw evaluation criteria for tunnel concrete linings were proposed.

• 한국수학교육학회지시리즈A:수학교육
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• 제54권3호
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• pp.223-240
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• 2015

This study qualitatively investigates the nature of the challenges that a student who is highly successful in mathematics faces in learning college-level elementary statistics. The study draws on the constructs of eagerness, flexibility and willingness to characterize the necessary disposition for critical thinking that is essential in learning statistics. The case study is based on data collected through a survey assessment and a follow-up interview with a mathematics major enrolled in an elementary college statistics course at the time of the study. The qualitative analysis relies on the student's verbal descriptions of the challenges he was experiencing in the course. The findings suggest that while his strong inclination towards inquisitive learning and strong understanding of mathematical concepts supported this student's mathematics learning, the same characteristics might have been causing him difficulties in learning college-level elementary statistics.

• 가족자원경영과 정책
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• 제6권2호
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• pp.119-132
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• 2002

In korea, it has been recently issued to enforce the 5 days-working system, which may cause the considerable increase in the leisure time and lifestyles. The purpose of this study is to find out major characteristics of leisure to establish the theoretical framework for leisure behavior by considering various theories. Each of theories provides the frame of thinking for leisure tim use, the relationship with labor, the transmission of leisure type and the change of leisure value and consciousness. Therefore findings will be the foundation for the future study that finds out more actual factors. Having examined how the leisure behavior is interpreted in various theories will help us to better understand why the demand for leisure time and activities has developed and will develope rapidly.

• 한국해양공학회지
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• 제22권6호
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• pp.52-57
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• 2008

The short-term high temperature creep rupture behavior of Ni-based Alloy718 steel was investigated at the elevated temperatures range of 550 to $700^{\circ}C$ under constant stress conditions. The creep rupture characteristics such as creep stress, rupture time, steady state creep rate, and initial strain were evaluated. Creep stress has a quantitative correlation between creep rupture tim and steady state creep rate. The stress exponents (n, m) of the experimental data at 550, 600, 650 and $700^{\circ}C$ were derived as 33.5, -24.9, 26.1, -21.2, 16.8, -12.8 and 10, -8.2, respectively. The stress exponent decreased with increasing creep temperature. The creep lift prediction was derived by the Larson-Miller parameter (LMP) method and the resultant equation was obtained as follows: T($logt_r$+20)=-0.00252 ${\sigma}^2$-1.377${\sigma}$+-22718.

• 한국의류산업학회지
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• 제16권1호
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• pp.26-34
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• 2014

This study considered movie costumes shown in 'Alice In Wonderland' by Tim Burton based on the Theory of Fantasy in Literature by Tzvetan Todorov and Rosemary Jackson. The research method used was a case study on expression types of fantasy used in movie costumes with a literature research based on the Theory of Fantasy in Literature. The Theory of Fantasy in Literature has significance in suggesting a new theoretical approach for understanding a visual perspective and aesthetic characteristics shown in fashion as well as movie costumes. The conclusions of the study are as follows. First, fantasy can connote characteristics of the marvelous, the uncanny, and the imitative through a consideration of Theory of Fantasy in Literature. Second, the marvelous is what is not beautiful, not ugly, but is strange and surprising, and what escapes from the existing norm. The characteristics of the marvelous in movie costumes are expressed through cross-dressing or displayed by allowing the personified animal to wear clothes. Third, the uncanny is something that causes grotesque, disgusting, comic and recreational responses. The characteristics of the uncanny in movie costumes are expressed through exaggerating and artificially transforming the body. Fourth, the imitative is the property of trying to imitate or follow other things. The characteristics of the imitative in movie costumes are indicated by dismantling and expanding a form through borrowing costumes from various ages.

• 대한방사선기술학회지:방사선기술과학
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• 제42권5호
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• pp.329-334
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• 2019

This study was purpose to quantitative evaluation of noise power spectrum(NPS) and studied the quantitative evaluation and characteristics of modulation transfer function(MTF) by obtain the optimal edge image by using Coil in magnetic resonance imaging(MRI) equipment through Fujita theory using edge method. The MRI equipment was used (Tim AVANTO 1.5T, Siemense healthcare system, Germany) and the head matrix coil were 12channels(elements) receive coil. The NPS results of showed the best value of 0.004 based on the T2 Nyquist frequency of $1.0mm^{-1}$, and the MTF results of showed that the T1 and T2 values were generally better than the T1 CE and T1 CE FC values. The characteristics of this study were to explain the characteristic method of image quality evaluation in general. To present the quantitative evaluation process and results in the evaluation of MRI image characteristics in radiology.

• International journal of advanced smart convergence
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• 제2권2호
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• pp.19-22
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• 2013

As the demand of the LED for lighting that emits light by p-n junction is increasing, studies on heatproof plate technology is being conducted to minimize the temperature of the LED lighting. As for the temperature of the LED devices, their light emitting efficiency decreases and the maximum lifespan drops down to 1/5. Therefore there are heat dissipation studies going on to minimize the heat. For LED heat dissipation, aluminum heat sink plates are mostly used. For this paper, we designed heat sink that fits residential 20W COB LED Down Light; packaged the heat sink and 20W COB and analyzed and evaluated the thermal properties through a Solidworks flow simulation. We are planning to design the optimal heat sink plate to solve the thermal agglomeration considering TIM(Thermal Interface material).

• 한국식품저장유통학회지
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• 제13권5호
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• pp.623-628
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• 2006

꽃향유로부터 정유물을 추출하여 천연향료로 개발하기 위하여 수증기증류법으로 추출하고 추출공정의 최적 조건을 반응표면 분석법으로 얻고자 하였다. 수증기증류법의 추출조건에 따른 꽃향유 추출물의 품질특성으로 수율과 총페놀화합물, 전자공여능과 주요 향기성분으로 estragole 과 thymol, beta-caryophyllene의 함량을 분석하였다. 추출온도가 추출시간보다 더 큰 영향을 주는 것으로 나타났으며, 각 품질 특성에 대하여 수립된 예측모델식이 모두 유의성이 높아 각 변수의 예측이 가능함을 보였다. 실험구간내에서 능선분석을 통하여 최대점과 추출조건을 예측하였으며 품질특성 값을 최대로 하는 제한 조건으로 얻어진 최적 추출조건은 $108^{\circ}C$와 2.1시간이었다.

• 한국주거학회논문집
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• 제26권5호
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• pp.89-96
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• 2015

This project was conducted as part of the Building America program that proposed the overall mission to achieve 30-50% reduction in existing building energy use. The purposes of this project were to analyze architectural styles and features named as archetypes of existing homes within the Great Lakes regions that include Michigan and identify the dominant type that would offer significant potential for energy-efficient retrofit. Housing archetypes were analyzed according to vintage, style, and construction characteristics in two target cities within the region. The findings from an intensive case study targeting the City of Ann Arbor established a fundamental framework for characterizing local housing archetypes and determined the dominant housing archetype that needed energy-efficient retrofit. An extended case study then conducted in Grand Rapids additionally refined this framework for the future application. This paper explained the process and data collection method to develop the framework that can be utilized by other researchers to determine the target housing types for energy-retrofit research.