• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.450.2-450.2
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• 2014

열전재료는 열-전기가 상호 가역적으로 변하는 재료로서, 최근 에너지 변환소재 분야에서 각광받고 있다. 열전재료의 특성 효율은 무차원 열전 성능지수(dimensionless figure of merit, $ZT={\alpha}2{\sigma}T/{\kappa}$)로 나타낼 수 있다. 여기서 ${\alpha}$는 제벡계수(Seebeck coefficient), ${\sigma}$는 전기전도도(electrical conductivity), ${\kappa}$는 열전도도(thermal conductivity), T는 Kelvin 온도를 나타낸다. 500 K에서 800 K까지의 중온 영역에서 우수한 열전특성을 보이는 $Mg_2X$ (X=Si, Ge, Sn)와 이들의 고용체는 성분원소가 독성이 없고, 매장량이 많아 친환경 열전 재료로 각광받고 있다. $Mg_2X$ 고용체 중 $Mg_2Si_{1-x}Ge_x$는 기존 $Mn_2Si$, $Mg_2Ge$, $Mg_2Sn$계 보다 더 우수한 열전 성능지수를 보인다. 다양한 제조 방법들이 시도되고 있으나, 조성설계 및 구조, 성능 조절의 어려움이 있고, Mg의 산화와 휘발 및 Mg, Si, Ge의 융점 차이가 크고 중력 편석과 반응하지 않은 원소들로 인해 제조가 상당히 어렵다. Sb가 도핑된 $Mg_2Si_{0.5}Ge_{0.5}Sb_y$ (y=0, 0.005, 0.01, 0.02, 0.03) 고용체를 고상반응으로 합성하고 진공열간 압축성형을 통해 성공적으로 제조하였다. 고용 상을 확인하기 위하여 X선 회절분석을 실시하였고, 고용체 형성과 도핑에 따른 전기적 특성변화를 평가하기 위해 Hall 효과를 측정하여 전자 이동특성을 분석하였고, 323~823 K까지 전기전도도, 제벡계수, 열전도도의 측정을 통해 열전 성능지수를 평가하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.61-64
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• 2013

Biomass is well known for organic resources photosynthesized by carbon dioxide water in the air and thus it can be widely used in the form of energy and production for various kinds of materials. Through pyrolysis, biomass can be transformed into solid(biochar), liquid(bio-oil), and combustible gas on the different condition of temperature and heating rate. That's why biomass can be practically used to preprocess and produce a variety of elements. This work is to analyze the characteristics of slow pyrolysis of three different kinds of biomass extracted from Indonesia. They showed similar moisture content and combinations of combustible matters and had quite a large discrepancy in the ash among them like 2.1 & of Bagasse, 91% of PKS, and 20.9% of Paddy Straw, respectively. yield of biochar, solid form of the biomass, steadily decreased when the temperature went up and that of bio-oil the highest at the temperature of 500 degrees Celsius. At the same temperature range, PKS bio-oil showed 51.4 % of yield and Bagasse had 55.1% while it turned out that Paddy straw showed the lowest yield of 37.2%. The apparent density was also measured to figure out the density of each product from the pyrolysis experiments at the temperature of 500 degrees Celsius. The result was like these; the density of biochar was 0.17, the lowest, and that of Tree stem was 1.3 when mixed by an equal amount of biochar and bio-oil.

• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.690-693
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• 2015

In this paper, in order to develop excellent Pb-free composition ceramics for ultrasonic sensor. The $SnO_2$-doped ($Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3$)(abbreviated as NKL-NST) ceramics have been synthesized using the ordinary solid state reaction method. The effect of $SnO_2$-doping on their dielectric and piezoelectric properties was investigated. The ceramics doped with 0 wt% $SnO_2$ have the optimum values of piezoelectric constant($d_{33}$), piezoelectric figure of merit($d_{33}.g_{33}$), planar piezoelectric coupling coefficient($k_p$) and density : $d_{33}=195[pC/N]$, $d_{33}.g_{33}=5.62pm^2/N.kp=0.40$, $density=4.436[g/cm^3]$. suitable for duplex ultrasonic sensor application.

• 한국정밀공학회지
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• 제19권2호
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• pp.87-94
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• 2002

Most of Rapid Prototyping (RP) process adopt a solid Computer Aided Design (CAD) model, slicing into thin layers of uniform, but not necessarily constant, thickness in the building direction. Each cross-sectional layer is successive1y deposited and at the same time, bonded onto the previous layers; the stacked layers form a physical part of the model. The objective of this study is to develop a method for calculating the rotation angle ($$\theta$_x, $\theta$_y$) of hotwire of the cutting system in the three-dimensional space for the Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-S). In order to examine the applicability of the developed method to VLM-S, various three-dimensional shapes. such as a screw, an extruded cross, and free surface bodies such as miniatures of the monkey(a figure of Sonokong), were made using the data obtained form the method.

• 한국추진공학회지
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• 제19권1호
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• pp.18-24
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• 2015

흡입 공기 온도가 연소 효율에 미치는 효과를 조사하기 위하여, 보론 카바이드가 충전된 그레인을 사용하여 실험을 수행하였다. 시험 결과 무차원화한 연소 효율은, 보론 입자의 증가된 연소 결과로 흡입 공기 온도가 올라감에 따라 증가하였다. 연소 효율은 증가하고 있지만, 반-실험적 방법에 의한 전반적인 효율은 온도가 올라감에 따라 감소하고 있다. 열입력 매개 변수와 연소실 마하 수를 변수로 브레이튼 사이클을 적용하여 분석하였으며 이들 두 인자가 성능에 여향을 미치고 있고, 실험 결과에서도 같은 추세를 보였다.

• 한국의류학회지
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• 제27권11호
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• pp.1260-1269
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• 2003

This paper endeavors to examine the most suitable formal dress design for mid-aged men who lives in Kwangju, the Republic of Korea. Visual effect in associate design is considered with adjustment, figured and the body type. There are partly similarity differences in associate design visual effect by one's shape and clothes design. Firstly, in thin type, striped figured suit is the most attractive. Single adjustment suit with striped figured tend to be attractive, young and modernistic. Single adjustment without figured is felt the mellowest. Secondly, in standard type, the suit without figured is perceived the most attractive and masculine. The suit with striped figured is looked more young. Single adjustment suit without figured is the most attractive and mellow also single adjustment with figured is felt the youngest. Double adjustment without figured is felt mellow and with striped figured is felt the most modernistic and familiar. Also double adjustment suit with check figured is felt more modernistic. Thirdly, in pyknic type, the solid figured and striped figured of the suits are felt more masculine and single without figured is thought attractive. Single adjustment with check figured is common image. Also, double adjustment with stripe figured is perceived attractive. In conclusion, the adjustment, number of button and figure are very important facts for the clothes for giving whole visual effect of men's suit.

• 한국시스템다이내믹스학회:학술대회논문집
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• 한국시스템다이내믹스학회 2000년도 하계학술대회발표논문집
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• pp.65-102
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• 2000

In 1987, The Brundtland Report defined a sustainable development as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This is the concept that we should cling to, to preserve natural resources of the present for the future generation. With this concept in mind, this paper criticized that the current waste management policy has been neglecting resource preservation aspect of waste management policy while giving too much emphasis on reducing waste generation. Thus, the purpose of this paper is to analyze how waste management policy can affect preservation of natural resources, and to investigate policy alternatives that can reduce both the volume of waste generated and the amount of natural resources that need to be consumed in the production process. The study was conducted based on the literature survey and system dynamics simulation. Borrowing Randers and Meadows's solid waste model with some modification of parameter and variables, this paper simulate several policy alternatives to figure out the most effective waste management policy set that can meet the need of the present without compromising the ability of the future generation to meet their own needs. Main concern was how to link waste management policy with resource management policy that can lead to minimization of waste generation and resource consumption.

• 에너지공학
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• 제27권1호
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• pp.40-50
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• 2018

Today, the development of industries and rapid urbanization has a profound impact on the human environment. It can be said that the environment in the craft village is most affected. The environment in these areas is severely degraded and depending on the type of production, the environment in the craft villages is different. In Phong Khe ward of Bac Ninh Province, Vietnam, there are over 204 small and large facilities of recycling and producing paper. The paper facilities produce about 200,000 tons of paper each year and the amount of paper produced is not less than 500 tons each day in Phong Khe. They are creating livelihoods for more than 6,000 workers and generating local budgets from VND- 50 billion to VND 60 billion per year. Despite this great contribution, the use of old machines and "backward" modes of production means that paper recycling has caused serious air, soil, and water pollution in the region. The specific objectives of this study were as follows: (1) provide an overview of paper production process in the Phong Khe paper craft village; (2) comprehensive literature review of the current status of water environment, atmosphere environment, soil environment and solid waste; (3) figure out about waste treatment in Phong Khe ward.

• 한국시스템다이내믹스연구
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• 제1권2호
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• pp.113-148
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• 2000

In 1987, The Brundtland Report defined a sustainable development as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This is the concept that we should cling to, to preserve natural resources of the present for the future generation. With this concept in mind, this paper criticized the current waste management policy has been neglecting resource preservation aspect of waste management policy while giving too much emphasis on reducing waste generation. Thus, the purpose of this paper is to analyze how waste management policy can affect preservation of natural resources, and to investigate policy alternatives that can reduce both the volume of wast geverated and the amount of natural resources that need to be consumed in the production process. The study was conducted based on the literature survey and system dynamics simulation. Borrowing Randers and Meadows's solid waste model with some modification of parameter and variables, this paper simulate several policy alternatives to figure out the most effective waste management policy set that can meet the need of the present without compromising the ability of the future generation to meet their own needs. Main concern was how to link waste management policy with resource management policy that can lead to minimization of waste generation and resource consumption.

• 복식문화연구
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• 제19권1호
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• pp.54-70
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• 2011

The purpose of this study is to examine the influence of celebrity and celebrity fashion on contemporary fashion. As study methods, the literature study using books and theses concerning fashion, culture, and history were used for theoretical background and visual data from magazine, news paper, and internet were used for actual study. The results of this study are as follows. First, the celebrity is the figure who shows their attractive appearance and status using major cultural contents on the basis of the various media and visual culture, and has secured a solid foothold as the source of fashion and an indispensable factor of fashion industry. Second, the celebrity fashion, a creature of mass media, set a powerful fashion trend along with the media, and increasingly plays mayor roles in the society and culture. Third, the combination of celebrity and fashion has come into the brightest spotlight as the serious business of today, and bring about a tremendous industrial ripple effect extensively.