• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.116.1-116.1
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• 2011

Materials with a combination of high electrical conductivity and optical transparency are important components of many electronic and optoelectronic devices such as liquid crystal displays, solar cells, and light emitting diodes. In this study, to fabricate a low-resistance and high optical transparent electrode film for organic photovoltaic, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll imprinted (TRI) poly-carbonate (PC) patterned films, the manufacture of high-conductivity and low-resistance Ag paste which was filled into patterned PC film using a doctor blade process and then coated with a thin film layer of conductive polymer by a spin coating process. As a result of these imprinting processes the PC films obtained a line width of $10{\pm}0.5{\mu}m$, a channel length of $500{\pm}2{\mu}m$, and a pattern depth of $7.34{\pm}0.5{\mu}m$. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of $9.65{\Omega}$/sq, optical transparency values were 83.69 % at a wavelength of 550 nm.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.250-253
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• 2007

An evaporated Ti/Pd/Ag contact system is most widely used to make high-efficiency silicon solar cells, however, the system is not cost effective due to expensive materials and vacuum techniques. Commercial solar cells with screen-printed contacts formed by using Ag paste suffer from a low fill factor and a high shading loss because of high contact resistance and low aspect ratio. Low-cost Ni and Cu metal contacts have been formed by using electroless plating and electroplating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Ni/Cu alloy is plated on a silicon substrate by electro-deposition of the alloy from an acetate electrolyte solution, and nickel-silicide formation at the interface between the silicon and the nickel enhances stability and reduces the contact resistance. It was, therefore, found that nickel-silicide was suitable for high-efficiency solar cell applications. The Ni contact was formed on the front grid pattern by electroless plating followed by anneal ing at $380{\sim}400^{\circ}C$ for $15{\sim}30$ min at $N_{2}$ gas to allow formation of a nickel-silicide in a tube furnace or a rapid thermal processing(RTP) chamber because nickel is transformed to NiSi at $380{\sim}400^{\circ}C$. The Ni plating solution is composed of a mixture of $NiCl_{2}$ as a main nickel source. Cu was electroplated on the Ni layer by using a light induced plating method. The Cu electroplating solution was made up of a commercially available acid sulfate bath and additives to reduce the stress of the copper layer. The Ni/Cu contact was found to be well suited for high-efficiency solar cells and was successfully formed by using electroless plating and electroplating, which are more cost effective than vacuum evaporation. In this paper, we investigated low-cost Ni/Cu contact formation by electroless and electroplating for crystalline silicon solar cells.

• 보존과학회지
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• 제35권5호
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• pp.416-429
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• 2019

보채는 지류문화재 보존처리의 마지막 단계로 주로 봉채를 사용한다. 본 연구는 지류문화재 보채에 쓰이는 4종의 봉채(본람, 등황, 연지, 대자)를 한지에 채색한 후 채색 양상을 확인하고 인공열화를 통해 색변화 양상을 확인하고자 하였다. 채색 양상을 관찰한 결과 본람·연지·대자는 미세한 안료 입자가 도포되는 형태였으며, 등황은 피막을 형성하였다. 봉채의 X선 회절분석 결과 본람과 연지, 대자에서 석영과 방해석, 납석이 공통적으로 검출되었고, 대자에서 침철석이 추가로 검출되었다. 인공열화 결과 습열열화에서 등황이 노란색에서 주황색으로 변색되었으며, 자외선열화에서는 등황과 연지가 탈색되었다. 결과적으로 봉채로 보채된 지류문화재는 등황이 채색된 경우 알칼리에 의해 주황색으로 변색될 수 있으며, 자외선에 의해 등황과 연지의 탈색이 우선적으로 발생하여 전체적인 색상이 어두워짐을 예측할 수 있다.

• Advances in environmental research
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• 제9권1호
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• pp.19-39
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• 2020

Urban heat island (UHI) is one of the most important climatic implications of urbanization and thus a matter of key concern for environmentalists of the world in the twenty-first century. The relationship between climate and urbanization has been better understood with the introduction of thermal remote sensing. So, this study is an attempt to understand the influence of urbanization on local temperature for a small developing city. The study focuses on the investigation of intensity of atmospheric and surface urban heat island for a small urbanizing district of Punjab, India. Landsat 8 OLI/TIRS satellite data and field observations were used to examine the spatial pattern of surface and atmospheric UHI effect respectively, for the month of April, 2018. The satellite data has been used to cover the larger geographical area while field observations were taken for simultaneous and daily temperature measurements for different land use types. The significant influence of land use/land cover (LULC) patterns on UHI effect was analyzed using normalized built-up and vegetation indices (NDBI, NDVI) that were derived from remote sensing satellite data. The statistical analysis carried out for land surface temperature (LST) and LULC indicators displayed negative correlation for LST and NDVI while NDBI and LST exhibited positive correlation depicting attenuation in UHI effect by abundant vegetation. The comparison of remote sensing and in-situ observations were also carried out in the study. The research concluded in finding both nocturnal and daytime UHI effect based on diurnal air temperature observations. The study recommends the urgent need to explore and impose effective UHI mitigation measures for the sustainable urban growth.

• 마이크로전자및패키징학회지
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• 제27권3호
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• pp.61-67
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• 2020

본 논문에서는 FEM(유한요소) 기법을 사용하여 칩이 실장되는 않은 substrate와 칩이 실장된 substrate의 warpage를 해석하여 칩의 실장이 warpage에 미치는 영향을 비교·분석하였다. 또한, warpage를 감소시키기 위한 substrate의 층별 두께의 영향도 분석과 층별 두께 조건을 다구찌법에 의한 신호 대 잡음 비로 분석하였다. 해석 결과에 의하면 칩이 실장되면 substrate의 warpage는 패턴의 방향이 변할 수 있고, 칩이 실장되면서 패키지의 강성도(stiffness)가 증가하고, 패키지 상·하의 열팽창계수의 차이가 작아지면서 warpage는 감소하였다. 또한, 칩이 실장되지 않은 substrate를 대상으로 설계 파라메타의 영향도 분석 결과에 의하면 warpage를 감소시키기 위해서는 회로층 중에서 내층인 Cu1과 Cu4를 중점 관리하고, 다음으로 바닥면의 solder resist 층의 두께와 Cu1과 Cu2 사이의 프리프레그 층의 두께를 관리해야 한다.

• 한국세라믹학회지
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• 제11권2호
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• pp.22-30
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• 1974

This study was carried out to investigate the species of iron compounds in kaolin mineral and the bonding relation between the major kaolin and its subordinate iron compound existing as incidental mineral in common clay by means of chemical composition, X-ray diffraction, thermal differential and thermogravimetrie analysis for the application of clays in the field of ceramic raw material. The domestic clay are produced abounduntly in many places, but San-Cheong kaolin, Chu-An clay, and Yeong-Am clay were selected as samples in this experiment because of their frequent utilization in porcelain industry. Two kinds of samples with low and high iron content are picked up respectively from the place of production and elutriated under two micron size to determine the properties and concentration of iron compound very fine particles or colloidal substance of low crystalline grade. Therefore, hydrothermal treatment in autoclave was conducted considering the existence of low crystalline grade of iron compounds known as an amorphoue state in X-ray diffraction pattern furthermore, de-iron treatment of hydrothermal compound was done in order to identify the related iron compound before and after hydrothermal reaction and iron compound which is one of the samples was synthesized for the determination of their compounds state in more detail. The obtained results in this study are as follows: In San-Cheong kaolin, Chu-An clay and Yeong-Am clay 1) It is proved that species accompanying iron compound is $\alpha$-FeOOH form. 2) Iron compound is composed of very fine particles or colloidal substance. 3) The iron substance encircles the fine parts of clay minerals under 2 micron and acts as cementizing agent.

• International Journal of Fluid Machinery and Systems
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• 제5권3호
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• pp.134-142
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• 2012

The competition to deliver ultra-low emitting vehicles at a reasonable cost is driving the automotive industry to invest significant manpower and test laboratory resources in the design optimization of increasingly complex exhaust after-treatment systems. Optimization can no longer be based on traditional approaches, which are intensive in hardware use and laboratory testing. The CFD is in high demand for the analysis and design in order to reduce developing cost and time consuming in experiments. This paper describes the development of a comprehensive practical model based on experiments for simulating the performance of automotive three-way catalytic converters, which are employed to reduce engine exhaust emissions. An experiment is conducted to measure species concentrations before and after catalytic converter for different loads on engine. The model simulates the emission system behavior by using an exhaust system heat conservation and catalyst chemical kinetic sub-model. CFD simulation is used to study the performance of automotive catalytic converter. The substrate is modeled as a porous media in FLUENT and the standard k-e model is used for turbulence. The flow pattern is changed from axial to radial by changing the substrate model inside the catalytic converter and the flow distribution and the conversion efficiency of CO, HC and NOx are achieved first, and the predictions are in good agreement with the experimental measurements. It is found that the conversion from axial to radial flow makes the catalytic converter more efficient. These studies help to understand better the performance of the catalytic converter in order to optimize the converter design.

• 천문학회지
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• 제38권4호
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• pp.471-478
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• 2005

Spectroscopic data obtained by the Infrared Interferometer Spectrometer (IRIS) aboard Voyager 1 and 2 have been re-visited. Using the spectroscopic data and footprints of the IRIS aperture on the planet, we constructed images of the stratosphere of Jupiter at the emission bands of hydrocarbons including $CH_4,\;C_2H_6,\;C_2H_2,\;C_3H_4,\;C_6H_6$, and $C_2H_4$. Thermal emission from the hydrocarbons on Jupiter originates from a broad region of the stratosphere extending from 1 to 10 millibars. We averaged the data using a bin of 20 degrees of longitude and latitudes in order to increase signal-to-noise ratios. The resultant images show interesting wave structure in Jupiter's stratosphere. Fourier transform analyses of these images yield wavenumbers 5 - 7 at mid-Northern and mid-Southern latitudes, and these results are different from those resulted from previous ground-based observations and recent Cassini CIRS, suggesting temporal variations on the stratospheric infrared pattern. The comparisons of the Voyager 1 and 2 spectra also show evidence of temporal intensity variations not only on the infrared hydrocarbon polar brightenings of hydrocarbon emissions but also on the stratospheric infrared structure in the temperate regions of Jupiter over the 4 month period between the two Voyager encounters. Short running title: Stratospheric Images of Jupiter derived from Voyager IRIS Spectra.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1529-1535
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• 2011

해상 운송 분야와 발전 플랜트 분야에서 사용되는 엔진은 저 중속에서 운전효율향상이 계속해서 요구되고 있다. 엔진의 운전효율향상을 위해서는 엔진상태를 나타내는 변수의 확인이 반드시 필요하다. 지금까지 가스압력, 가스온도, 진동 등이 주요변수로써 제안되고 있으나 이 변수들은 응답속도와 진단 정확성에 한계가 있다. 본 연구에서는 엔진 크랭크 축 각속도 변화를 수치화한 EFR(Engine Fitness Ratio)을 검출하고, 이를 기반으로 엔진의 상태를 진단하는 기법을 개발하였다. EFR은 주파수 영역에서 특정 주파수의 비로써 정의되며 엔진상태를 나타낸다. EFR은 크랭크 각속도의 변화 거동으로부터 계산되며, EFR을 이용한 엔진 상태진단 기법을 실제 선박 추진용 저속엔진을 이용한 실험과 발전용 중속엔진을 이용한 해석을 수행하여 엔진의 이상 발생 감지가 가능함을 검증하였다.

• 한국의류학회지
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• 제30권2호
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• pp.306-315
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• 2006

Today, the uniform is perceived being important, because it transmits the unique company image through visualization of images, improves efficiency of work, and increases the feeling of belonging. Therefore, the purpose of this project was to make the winter uniform for the personnel in the manufacturing and the business departments of Korea Tobacco and Ginseng Corporation. The functional, aesthetic, and symbolic aspects were fully considered throughout the design process for the new uniform. To reflect the worker's opinions, the questionnaire method was used. The questionnaire was made up of the questions about the evaluation criteria and design preference for uniform. The result of the survey was reflected on the uniform design. The uniform consists of a jumper and a pair of pants. The jumper for manufacturing workers has two patched pockets with gussets. It has a convertible collar and a horizontal tuck on front panel. It has an open fastener on the front and a flap to cover the fastener. It has two types of pockets inside for functional reason. The welt one is for a wallet and the small one is for a pen. For the material, melanges with two tones of gray color was used, so it gave the sophisticated look on the uniform. The jumper for business workers also has a convertible collar and inside pockets. It has two slant slash pockets with welt. In addition, it has an attachable fur collar which gives thermal protection and aesthetic effect. The fabric has small check pattern and was made of wool. The pants are a basic trouser style with two pleats on the front.