• Journal of Mushroom
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• v.12 no.4
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• pp.270-274
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• 2014

In previous studies, we selected the green LED(light emitting diodes) for suitable wavelength of the light by higher commercial yields and lower ratio of the abnormal fruit body in Lentinula edodes. In this study, we aimed to select efficient irradiation intensity of the green LED. Stronger irradiation intensity of the green LED resulted in more polyphenol content of fruit body. And Polyphenol content of fluorescent lamp was similar to that of the green LED $20umol{\cdot}m^{-2}{\cdot}s^{-1}$.. Ergosterol content of the green LED $5umol{\cdot}m^{-2}{\cdot}s^{-1}$ was showed higher 2.1 times than that of the fluorescent lamp. In four level of irradiation intensity, 5, 10, 15, $20umol{\cdot}m^{-2}{\cdot}s^{-1}$ there was no big difference in characteristics of the fruit body. However the yield of fruit body in the green LED $5umol{\cdot}m^{-2}{\cdot}s^{-1}$ is higher than the others. In addition, The amount of electricity used of the green LED $5umol{\cdot}m^{-2}{\cdot}s^{-1}$ was reduced 15.9% than that of the fluorescent lamp. In conclusion, we selected $5umol{\cdot}m^{-2}{\cdot}s^{-1}$ for suitable irradiation intensity in Lentinula edodes with sawdust substrate cultivation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.36-42
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• 2019

Europe and North America are paying attention to residential ESS(Energy Storage System) that can manage energy efficiently. The ESS is a system that stores and manages the electric power by charging and discharging the battery. The ESS is generally used in conjunction with photovoltaic systems. The ESS supplies the load of the power generation time and stores the remaining PV power to supply the load at the non-power generation time. However, due to the high price of residential ESS, low electric rates and increasing block rates, there is no market of residential ESS in Korea. This paper reviews the price condition and the capacity for applying PV and residential ESS to household of apartments using HOMER in Korea.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.620-626
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• 2015

$Ho^{3+}$ doped $SrAl_2O_4$ upconversion phosphor powders were synthesized by spray pyrolysis, and the crystallographic properties and luminescence characteristics were examined by varying activator concentrations and heattreatment temperatures. The effect of organic additives on the crystal structure and luminescent properties was also investigated. $SrAl_2O_4:Ho^{3+}$ powders showed intensive green emission due to the $^5F_4/^5S_2{\rightarrow}^5I_8$ transition of $Ho^{3+}$. The optimal $Ho^{3+}$ concentration in order to achieve the highest luminescence was 0.1%. Over this concentration, emission intensities were largely diminished via a concentration quenching due to dipole-dipole interaction between activator ions. According to the dependence of emission intensity on the pumping power of a laser diode, it was clear that the upconversion of $SrAl_2O_4:Ho^{3+}$ occurred via the ground state absorption-excited state absorption processes involving two near-IR photons. Synthesized powders were monoclinic as a major phase, having some hexagonal phase. The increase of heat-treatment temperatures from $1000^{\circ}C$ to $1350^{\circ}C$ led to crystallinity enhancement of monoclinic phase, reducing hexagonal phase. The hexagonal phase, however, did not disappear even at $1350^{\circ}C$. When both citric acid (CA) and ethylene glycol (EG) were added to the spray solution, the resulting powders had pure monoclinic phase without forming hexagonal phase, and led to largely enhancement of crystallinity. Also, N,N-Dimethylformamide (DMF) addition to the spray solution containing both CA and EG made it possible to effectively reduce the surface area of $SrAl_2O_4:Ho^{3+}$ powders. Consequently, the $SrAl_2O_4:Ho^{3+}$ powders prepared by using the spray solution containing CA/EG/DMF mixture as the organic additives showed about 168% improved luminescence compared to the phosphor prepared without organic additives. It was concluded that both the increased crystallinity of high-purity monoclinic phase and the decrease of surface area were attributed to the large enhancement of upconversion luminescence.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.12
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• pp.913-921
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• 2011

This study examined the overall feasibility of low carbon green village formed in rural area. The check method is analyzing its environmental and economic feasibility and energy self-reliance. The biomass of the villages was set as 28 ton/day of livestock feces and 2 ton/day of cut fruit tree branches which make up the total of 30 ton/day. The facility consisted of a bio gasfication facility using wet (livestock feces) biomass and combined heat power generator, composting facility and wood boiler using dry (cut fruit tree branches) biomass. When operating the system, 540,540 kWh/yr of electricity and 1,762 Gcal/yr of heat energy was produced. The region's electricity energy and heat energy self-reliance rate will be 100%. The economic feasibility was found as a loss of 140 million won where the facility installation cost is 5.04 billion won, operation cost is 485.09 million won and profit is 337.12 million won. There will be a loss of about 2.2 billion won in 15 years but in the environmental analysis, it was found that crude replacement effect is about 178 million won, greenhouse gas reduction effect is about 92 million won making up the total environmental benefit of 270 million won. This means, there will be a yearly profit of about 130 million won. In terms of its environmental and economic feasibility and energy self-reliance, this project seemed to be a feasible project in overall even if it manages to get help from the government or local government.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.24-28
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• 2009

본 논문에서는 청색 인광 발광 물질인 bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium (III) (Flrpic)과 녹색 인광 발광 물질인 fac-tris(2-phenypyridine) irdium(III) ($Ir(ppy)_3$)와 적색 인광 발광 물질인 his(5-benzoyl-2-phenylpyridinato-C,N)iridium(III) (acetylacetonate) ($(Bzppy)_{2}Ir(acac)$)를 각각 적층하여 백색 유기 발광 다이오드를 제작하였고, 각각의 발광층 사이에 혼합된 스페이서인 4,4'-N,N'-dicarbazole-biphenyl (CBP):4,7-diphenyl-1,10-phenanthroline (BPhen)을 적층하여 그 때의 영향에 대하여 연구하였다. 최적화된 구조에서의 전력 효율은 $0.014\;mA/cm^2$에서의 19.7 lm/w를 나타내었으며, $0.127\;mA/cm^2$에서의 11.5%의 외부 양자 효율을 나타내었고, 8 V에서 Commission Internationale do I'Eclairage ($CIE_{x,y}$) coordinates (x=0.36, y=0.44)의 색좌표를 나타내었다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.102-108
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• 2011

The existing vessels lighting control system has several problems, which are complexity of construction and high cost of establishment and maintenance. In this paper, We designed low cost and high performance lighting control system at digital vessel environment. We proposed a system which recognize the user's emotions after obtaining the biological informations about user's bio information(pulse sensor, blood pressure sensor, blood sugar sensor etc) through wireless sensors controls the LED Lights. This system classified emotions using backpropagation algorithm. We chose 3,000 data sets to train the backpropagation algorithm. As a result, obtained about 88.7% accuracy. And the classified emotions find the most appropriate point in the method of controlling the waves or frequencies to the red, green, blue LED Lamp comparing with the 20-color-emotion models in the HP's 'The meaning of color' and control the brightness or contrast of the LED Lamp. In this method, the system saved about 20% of the electricity consumed.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.271-275
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• 2011

According to governmental policies for green growth, the increase in the traffic volume of railroad is a representative method to reduce total greenhouse gas (GHG) emitted from transport. Comprehensive assessment for the GHG emission of railroad has been studied to compare the difference of transport modes just in the operating step excluded the construction step. The purpose of this study was to evaluate GHG emissions in railroad construction sector. The targets were some construction works for civil, track, building, and electric system in A line. The GHG emission source of constructing railroad infrastructure was mainly the energy consumption of heavy equipments. As a result, the civil construction sector showed more than 96% of total GHG emissions and its specific GHG emission was 2.191 ton $CO_2e/m$. Also, the specific GHG emissions of civil construction works were of the order: earthworks > tunnels > bridges > station. In future, it will be required to calculate the overall GHG emission of railroad through life cycle approaches including operation, maintenance and disposal step.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.119-119
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• 2010

다층박막구조를 갖는 유기발광소자는 저분자 증착 기술이 발전함에 따라 다양한 구조로 제작이 가능해 다양한 구조 설계를 통하여 발광특성을 향상할 수 있게 되었다. 다층박막구조에서 유기발광소자의 발광효율을 향상시키기 위하여 다양한 주입층과 수송층을 사용하여 전하의 주입 장벽과 이동도를 제어할 수 있다. 저분자 유기발광소자에서 가장 많이 이용되는 tris(8-hydroxyquinoline) aluminum (Alq3) 또는 7-diphenyl-1, 10-phenanthroline (BPhen)을 단일구조로 전자수 송층으로 사용한 유기발광소자의 발광 메커니즘에 대한 연구가 많이 진행되었지만, Alq3 와 BPhen 을 같이 사용하였을 때 나타나는 전기적 특성과 광학적 특성에 대한 연구는 미미하다. 따라서 본 연구에서는 전자 수송층으로 Alq3 와 BPhen 을 다중 이종구조를 사용하여 녹색 유기발광소자를 제작하고 이의 전기적 특성과 광학적 특성을 연구하였다. 유기발광소자를 제작한 후 Alq3와 BPhen 다중 이종구조의 위치와 이종구조 개수의 변화에 따라 발광 특성 비교를 위하여 인가된 전압에 대한 전류밀도와 휘도, 발광 효율 및 전력 효율을 측정하였다. 다중 이종구조로 제작할 경우 단일 BPhen층의 두께가 얇아지기 때문에 단일 이종구조의 소자보다 BPhen층의 정공차단 능력이 저하되어 저전압에서는 Alq3/BPhen 계면에서의 누설되는 정공의 수가 증가하였다. 또한 이종구조의 수가 증가할수록 단일 이종구조일 때에 비하여 인가된 전압에 대한 전류밀도가 감소하였다. 이는 Alq3와 BPhen 내에서 각각 전자의 이동도가 다르기 때문에 Alq3/BPhen 이종계면에서 전자가 축적되어 공간전하를 형성하므로 내부전계가 형성되어 구동전압이 증가하는 것으로 보인다. 그러나 다중 이종구조로 된 전자 수송층을 포함한 유기발광소자의 발광 효율은 구동전압의 변화에 따라 변하지 않는다. 이종계면의 수가 증가함에 따라 각각의 이종계면에서 축적되는 전자의 양이 감소하기 때문에 고전압에서 발광효율의 저하가 감소하였다. 그러므로 다중 이종구조를 가진 전자수송층 내에서 전자의 주입과 수송에 대한 원리는 안정화된 발광효율을 가지는 유기발광소자를 제작하는데 중요하다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.553-556
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• 2013

Currently green growth and energy saving are major issues and solution using low-power LED lighting devices are gaining popularity. There are a few standards to control these LED lighting equipment and DMX512 protocol is a typical communication control standard used. DMX512 lighting control protocol is one of standard protocols widely used in various fields which include mainly stage lighting and landscape lighting. But in DMX512 protocol, line is to be connected to a wired connection. Advantage of wired connection is stable data transfer operation but it adds complexity and certain constraints as well in wired connection. To solve this problem, wired connection can be replaced efficiently with a wireless connection but for wireless, problem of data loss and two way communications arises. In this paper, these problems of wireless communication for DMX512 have been addressed and solutions for two way communications and data loss problem have been proposed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.479-479
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• 2012

유기발광소자는 낮은 구동전압, 저전력, 높은 명암비, 빠른 응답속도, 넓은 시야각 및 높은 박막의 특성을 가지고 있어서 차세대 평판 패널디스플레이 기술로 각광받고 있다. 하지만 청색 유기발광소자는 적색과 녹색 유기발광소자에 비해 낮은 신뢰성, 발광효율 및 색 순도의 문제점을 가지고 있어, 이를 개선하기 위한 연구가 다양하게 연구되고 있다. 청색 유기발광소자의 경우 발광층 내부로 주입되는 정공과 전자의 균형을 조절하기 위해 p-i-n 구조를 사용하거나 이리듐-유기물 합성물과 같은 인광물질의 적용하여 발광효율을 높이는 청색 유기발광소자에 대한 연구가 진행되고 있다. 하지만 정공 보조층과 청색 형광층의 도핑구조의 청색 유기발광소자에 대한 발광효율 증가 메커니즘에 관한 연구는 비교적 많이 이루어지지 않았다. 본 연구에서는 열 증착 방법을 이용하여 정공 보조층과 청색 형광층으로 구성된 이중 발광층을 사용한 청색유기발광소자의 발광효율 증가 메커니즘에 대해 연구하였다. 10%의 2,9-dimethyl-4,7-diphenyl-1,10-phenanthorlene (BCP)로 도핑된 2-methyl-9,10-bis(naphthalene-2-yl)anthracene (MADN)층을 발광층으로 사용한 유기발광소자, 5% MADN으로 도핑된 1, 3-bis(carbazol-9-yl)benzene (mCP) 층을 발광층으로 사용한 소자 및 10% BCP로 도핑 된 MADN 층과 5% MADN로 도핑 된 mCP층을 혼합하여 발광층으로 사용한 소자의 전류밀도-전압-발광 특성을 비교하여 청색 유기발광소자의 발광효율 증가 메커니즘을 분석하였다. 이중 발광층을 가지는 소자는 두 단일 발광층 중심부의 경계면에서 축적된 정공에 의해 발생한 쿨롱 인력으로 더 많은 전자들을 끌어들이게 되어 엑시톤 형성 및 빛 방출이 증가하였다. 이 실험의 결과는 MADN 형광물질을 가진 청색 유기발광소자의 발광효율 증가 메커니즘에 대한 이해를 높이는데 도움을 줄 수 있다.