• 전기학회논문지P
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• 제63권4호
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• pp.283-289
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• 2014

A Fresnel lens is an optical component which can be used as a cost-effective, lightweight alternative to conventional continuous surface optics. Fresnel lens solar concentrators continue to fulfill a market requirement as a system component in high volume cost effective Concentrating Photovoltaic (CPV) electricity generation. The basic principles of the fresnel lens are reviewed and some practical examples are described. To investigate the performance space of the Fresnel lens, a fast simulation method which is a hybrid between raytracing and analytical computation is employed to generate a cache of simulation data. Injection molders are warming up to the idea of cycling their tool surface temperature during the molding cycle rather than keeping it constant. Heat and cool process are now also finding that raising the mold wall temperature above the resin's glass-transition or crystalline melting temperature during the filling stage and product performance in applications from automotive to packaging to optics. This paper deals with the suitability of Fresnel lenses of imaging and non-imaging designs for solar energy concentration. The concentration fresnel lens confirmed machinability and optical transmittance and roughness measure through manufactured the prototype.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.744-751
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• 2003

Co-Pd alloy thin films prepared by a DC-sputter that have self-organized nano structure(SONS), are promising for high-density information storage media in information era. We prepared the samples by varying Pd contents of 0~8.1 wt% at the substrate temperatures of room temperature (RT) and 200 $^{\circ}C$, respectively Microstructure and Pd contents of the Co$_{1-x}$ Pd$_{x}$ films are probed by a scanning electron microscope (SEM), a transmission electron microscope (TEM) and an energy dispersive spectrometer (EDS). We also investigated the saturation magnetization (Ms), remanence and coercivity of the Co$_{1-x}$ Pd$_{x}$ films. Surface roughness are measured by an atomic force microscope (AFM). We revealed that self-organized nano size Co-enriched phase and Pd-enriched phase existed with Pd contents at the substrate temperatures of RT and 20$0^{\circ}C$ through microstructure characterization. SONS helped to keep the saturation magnetization and enhance the perpendicular anisotropy with Pd contents. Out result implies that we may tune the perpendicular magnetic properties with keeping the saturation magnetization by varying substrate temperatures and Pd contents for high density magnetic recording.rding.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.190-190
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• 2010

Zinc oxide is the most attractive material due to the large direct band gap (3.37 eV), excellent chemical and thermal stability, and large exciton binding energy (60 meV). Recently, ZnO nanorods were used as the high efficient antireflection coating layer of solar cells based on silicon (Si). In this reports, we studied the effects of rapid thermal annealing (RTA) treatment on optical properties of ZnO nanorods. For fabrication of ZnO nanorods, there are many methods such as hydrothermal method, sol-gel method, and metal organic chemical vapor deposition method. Among of them, we used the conventional wet chemical method which is simple and low temperature growth. In order to synthesize the ZnO nanorods, the ZnO films were deposited on Si substrate by RF magnetron sputtering at room temperature and the samples were dipped to aqua solution containing the zinc nitrate and hexamethylentetramines (HMT). The synthesis process was achieved in keeping with temperature of $90-95^{\circ}C$ and under constant stirring. The morphology of ZnO nanorods on glass and Si was characterized by scanning electron microscopy. For the analysis of antireflection performance, the reflectance and transmittance were measured by spectrophotometer. And for analyzing the effects of RTA treatment on ZnO nanorods, crystalline properties were investigated by X-ray diffraction measurements and optical properties was estimated by photoluminescence spectra.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.115-120
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• 2009

The studies for mechanical performance development have been examined to reduce energy consumption in building construction field. However, The energy consumption using in building for heating is impacted by not only system performance but also PMV particularly at temperature and clo. Most energy using in building part is mainly consumed for heating and cooling to keep comfort temperature. Heating energy consumption is bigger than cooling energy in Korea because of temperature difference in winter in comparison with summer at apartment building. This means that energy consumption can be changed by occupancy's comfort setting temperature in apartment building. This study evaluate actual comfort temperature range by clo and examined heating energy consumption by Esp-r and CO2 reduction possibility. The results show that keeping ASHRAE standards can reduce heating energy up to 23%; also, wearing underclothes with ASHRAE standard can reduce heating energy up to 47.8%. Option 4 showing Maximum CO2 emission reduction indicates that kerosene. LNG and electricity can reduce 1.5t, 1.7t, 2.46t respectively in comparison with option 2.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1285-1290
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• 2008

The interest in use of new field of energy and unused existing potential energy has been raised in number of advanced countries including South Korea. As a respond of the interest and the following reactions, a new technology which helps to reduce bad environmental factors and decrease national energy consumption rate in the way of extract cold-heat energy in dam water. This research focuses on a method that enables taking the water flows in desirable temperature range whilst keeping water temperature boundaries of bottom level water. The analysis was made in simulating on CFD. In order to keep the temperature boundary level, a deep well pump was set in piping in the simulation. As the significant result, the most alteration in temperature was found when the smallest size of pipe was plumbed. However, when the flow has small value of velocity, no matter how big the piping size was, the temperature variation was negligible. Therefore, possible hypothesis was made as bigger piping as fast flow will have better function in the way to keep the temperature boundary level.

• 한국조리학회지
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• 제16권4호
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• pp.220-229
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• 2010

본 연구는 잎차용 3가지 형태의 기존 다기의 구조에 따른 문제점을 조사하고, 그 문제점을 해결하기 위해서 개발한 잎차용 빨대의 효과를 조사하였는데 다음과 같은 결과를 얻었다. 기존의 다기로 잎차를 우려 마실 때 잎차를 일차적으로 차 우림 용기에 넣고 데운 찻물을 부어 우린 다음 여과 과정을 거친 다음 별도의 차액의 표면적인 극적으로 증가되는 과정이 필연적이기 때문에 차액의 온도가 음용 적은 이하로 냉각되기 쉬운 문제와 공기와의 접촉에 의한 차액의 맛과 향이 감소되는 문제가 있었다. 이처럼 기존 다기 사용에서 공통적으로 일어나는 차액의 공기와의 접촉 면적과 시간을 최소화하기 위해서 바닥이 평면인 원통 수직 벽면의 최 하단으로부터 5mm 높이 내에 직경이 1~2 mm인 수 개의 여과구를 단층으로 형성한 잎차용 빨대를 개발하였다. 이 잎차용 빨대는 잎차를 우린 다음 차액을 거르지 않고 우림 용기에 직접 꽂아 음용할 수 있어 기존 다기를 사용한 경우보다 차액의 온도가 높게 유지되어 따뜻한 차액을 음용할 수 있었고, 관능적 평가에서 차 향 및 입안의 느낌을 포함한 전체적인 차 맛이 개선되는 효과가 있었다(p<0.05).

• 한국약용작물학회지
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• 제23권4호
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• pp.305-310
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• 2015

This study was conducted to obtain the basic data related to seed characteristics and germination conditions of the Coriandrum sativum L. at different storage condition and temperature. The shape of fruit was oval with light brown color. Fruit was mericarp, biloculate, with one ovule in each locus. The length and width of seed were $1.37{\pm}0.067mm$ and $0.52{\pm}0.039mm$, respectively. Weight of 1,000 seeds was $6.55{\pm}0.15g$. Seeds which were stored at room ($15^{\circ}C$) and cold temperature ($4^{\circ}C$) in vinyl container showed the highest germination rate (93.3%) under the room temperature germination condition. Percentage of germination in cold and freeze temperature was 20% and 0%, respectively. Germination rate of room storage seeds with paper container increased to about 91.3%, however, decreased in cold ($4^{\circ}C$) and freeze storage ($-20^{\circ}C$) with paper container (76.7% and 78.0%, respectively). Germination rate of seed in vinyl stock container was better than that of paper stock container. Germination rate of seeds stored at room temperature for 4 years (2010 - 2013) ranged from 80.0% to 91.3%. Therefore, coriander seeds are expected to be stored at room temperature for increasing the germination rate and keeping a long term.

• International Journal of Industrial Entomology and Biomaterials
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• 제24권2호
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• pp.69-74
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• 2012

Tropical tasar silkworm Antheraea mylitta Drury experiences extreme temperature stress conditions during its life cycle particularly during diapauses and first crop. The present study witnessed the impact of high temperature on some biochemical profiles and egg production (fecundity) of semi-domesticated Daba and Shorea robusta (Sal) based wild ecorace Laria during seed cocoon (pupa) preservation. Cocoons of Daba and Laria were treated with high temperature at $40^{\circ}C$ for 10 days in a BOD incubator. The protein profile and carbohydrate content in the hemolymph and fat body and total haemocyte count (THC) in the hemolymph of pupa were investigated. Further, the fecundity and fertility of egg was assessed. Significant increase in the protein concentration was observed in the hemolymph with reduction in the fat body (p<0.05). The difference in protein concentration was highly significant between the semidomesticated Daba and wild ecorace Laria (p<0.05). High pupal mortality (20%) and reduced fecundity (10-15%) in Daba was noticed compared to wild Laria. Also an increased THC (>28000) was recorded in Laria. The study infers the potentials of wild ecoraces in sustaining the extreme temperature conditions and need of adopting suitable package of practices for the preservation of diapause seed cocoons during extreme summer conditions. There is possibility to introgression thermal stress resistant traits in the semi-domesticated races of tasar silkworm by resorting to conventional breeding plans with wild races and keeping the thermal stress induced response as markers.

• Journal of Biosystems Engineering
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• 제31권3호
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• pp.168-174
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• 2006

The purpose of this study is to develop the cold chain system by developing optimal phase change materials (PCM). There are some benefits from developing this system such as keeping freshness of agriculture products, saving energy, etc. The major results are as follows. To decide a latent heat material, the characteristics of water, sodium, polyacrylate, ethanol and N-tetradecane are analysed. Also, an insulating material is made by mixing water, nucleating agent and latent heat material, using cementing method. In addition, the sensitivity analysis for developed latent heat material($K_l,\;K_2,\;K_3$) is conducted. For $K_l,\;K_2,\;K_3$ which cans keep latent heat temperature, ranging from $0\;to\;5^{\circ}C,\;5\;to\;10^{\circ}C,\;10\;to\;15^{\circ}C$. it can keeps latent heat temperature at radiant heat (5, 12, $17^{\circ}C$) and transportation latent heat container both melting temperature and amount of latent heat of Kl are $-1.6{\pm}1.0^{\circ}C$, 326.51 J/g, respectively and freezing temperature and latent heat are $-7.98{\pm}1.5^{\circ}C$ and 174.18 J/g. and $K_2$ are $7.41{\pm}1.5^{\circ}C$, 89.80 J/g, respectively and freezing temperature and latent heat are $-2.14{\pm}1.5^{\circ}C$ and 83.90 J/g. and $K_3$ are $9.54{\pm}1.0^{\circ}C$, 145.42 J/g, respectively and freezing temperature and latent heat are $0.21{\pm}1.0^{\circ}C$ and 152.48 J/g.

• 한국식품과학회지
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• 제24권5호
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• pp.515-518
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• 1992

창평쌀엿의 최적 품질유지 조건을 찾고저 저장온도에 따른 관능검사, puncture force의 측정, 단면의 모양 변화 및 색도의 변화 등을 실험하고 종합 분석하여 본 결과 저장온도 $10^{\circ}C$까지는 품질의 변화를 찾기 어려웠다. $15^{\circ}C$ 이상에서는 품질특성이 나빠지기 시작하며 1주일 후에는 엿끼리 서로 들어붙기 시작하였다. 저장온도 $15^{\circ}C$ 이상에서는 각각의 엿이 서로 들어붙고, 먹을 때의 느낌도 좋지 못하며 치아에 들어붙어서 창평 쌀엿의 고유한 품질특성을 상실하였다. 따라서 창평쌀엿 고유의 품질을 최적상태로 유지하기 위한 한계 온도는 $12{\sim}13^{\circ}C$로 추정되었다.