• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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• pp.177-179
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• 2009

Solar, as an ideal renewable energy, it has inexhaustible, clean and safe characteristics. However, solar energy is an extreme intermittent and inconstant energy source. In order to improve the photovoltaic system efficiency and utilize the solar energy more fully, and the DC current varies with the irradiation, it is necessary to study the characteristics of photovoltaic I-V according to the external factors. This paper presents the analysis of characteristics of photovoltaic I-V according to the irradiation.

• 한국기계가공학회지
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• 제9권4호
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• pp.26-31
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as solar energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. The solar tracker consists of sun point detector module, mechanical mechanism module with actuator and control system module. This paper presents sun point detector for solar tracker of daylight system. To evaluate the detecting accuracy, an experimental device is implemented. In experimental results, the accuracy of development system has under 0.11%/0.5deg.

• Journal of Biosystems Engineering
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• 제14권4호
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• pp.262-271
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• 1989

Red pepper is one of the most important agricultural products in Korea. Generally, raw red pepper is dried after harvest and the dried red pepper is powdered. Washing process is necessary to produce clean powder before powdering process. This study, therefore, was performed to analyze the drying characteristics of the rewetted red pepper and the energy utility during hot-air-convective and infrared-radiant drying. Drying effectiveness, De, was defined for the analysis of energy utility in this study, and its value was determined according to the energy source. Infrared-radiant drying was more favorable than convective drying according to drying effectiveness. But the temperature variation was appeared between the radiant surface and opposite surface of red pepper in infrared-radiant drying.

• 한국분무공학회지
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• 제2권3호
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• pp.44-50
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• 1997

Bio-diesel oil is a great possibility to solve the pollution problem caused by the exhaust gas from diesel engine vehicles. Recently the use of bio-oils in disel engines has received considerable attention to the forseeable depletion of world oil supplies. So, Bio-diesel oil has been attracted with attentions as an alternative and clean energy source. The objective of this paper is to experimentally investigate the characteristic of performance using light oil, rice-bran oil, heated rice-bran oil, rice-bran oil treated with ultrasonic energy. We included rice-bran oil and applied ultrasonic energy to highly viscous bio-oils. These methods seems to have never been tried yet. The final data may be able to be applicated for the design of the diesel engine using an alternative fuel.

• 한국기계가공학회지
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• 제9권1호
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• pp.67-73
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as sun energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. This paper presents design and evaluation of 1 layer polar motion control system for solar tracker suitable for building integrated system. To evaluation of tracking accuracy and adaptability, solar tracker with 64 links is implemented. In experimental results, the accuracy of tracking has under ${\pm}0.0287^{\circ}$ and the thickness has under 140mm.

• Journal of the Korean Wood Science and Technology
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• 제47권4호
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• pp.442-450
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• 2019

Despite its potential as a renewable source for fuels and chemicals, lignin valorization still faces technical challenges in many aspects. Overcoming such challenges associated with the chemical recalcitrance of lignin can provide many opportunities to innovate existing and emerging biorefineries. In this work, we leveraged a biomass genetic engineering technology to produce phenolic aldehyde-rich lignin structure via downregulation of cinnamyl alcohol dehydrogenase (CAD). The structurally altered lignin obtained from the Arabidopsis thaliana CAD mutant was pyrolyzed to understand the effect of structural alteration on thermal behavior of lignin. The pyrolysis was conducted at 400 and $500^{\circ}C$ using an analytical pyrolyzer connected with GC/MS and the products were systematically analyzed. The results indicate that aldehyde-rich lignin undergoes fragmentation reaction during pyrolysis forming a considerable amount of C6 units. Also, it was speculated that highly reactive phenolic aldehydes facilitate secondary repolymerization reaction as described by the lower yield of overall phenolic compounds compared to wild type (WT) lignin. Quantum mechanical calculation clearly shows the higher electrophilicity of transgenic lignin than that of WT, which could promote both fragmentation and recondensation reactions. This work provides mechanistic insights toward biomass genetic engineering and its application to the pyrolysis allowing to establish sustainable biorefinery in the future.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.915-920
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• 2001

A spent fuel problem has prevented the nuclear power from claiming to be a completely clean energy source. The nuclear transmutation technology to incinerate the long lived radioactive nuclides and produce energy during the incineration process is believed to be one or the best solutions. HYPER(Hybrid Power Extraction Reactor) is the accelerator driven transmutation system which is being developed by KAERI(Korea Atomic Energy Research Institute). Some major feature of HYPER have been developed and employed. On-power fueling concepts are employed to keep system power constant with minimum variation of accelerator power. A hollow cylinder-type metal fuel is designed for the on-line refueling concept. Lead-bismuth(Pb-Bi) is adopted as a coolant and Spallation target material. HYPER is a subcritical reactor which needs an external neutron source. 1GeV proton beam is irradiated to Lead-bismuth(Pb-Bi) target inside HYPER, and spallation neutrons are produced. When proton beams are irradiated, much heat is also deposited in the Pb-Bi target and beam window which separates Pb-Bi and accelerator vacuum. Therfore, an effective cooling is needed for HYPER target. In this paper, we performed the thermal-hydraulic analysis of HYPER target using FLUENT code, and also calculated thermal and mechanical stress of the beam window using ANSYS code.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.206.1-206.1
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• 2011

Recently, various developments in the area of small hydropower have being made and small hydro turbines are suitable for domestic use because it is a clean and renewable energy source. A small hydropower generator produces power by using the different water pressure levels in pipe lines and energy which was initially wasted by use of a reducing valve at the end of the pipeline is instead collected by a tubular-type hydro turbine in the generator. In this study, in order to acquire the performance of tubular-type hydro turbine applied, the output power, head, efficiency characteristics due to the different guide vane and runner vane angle are examined in detail. Moreover, influences of pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.192-195
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• 2004

Into investment expense that wind generation system that is one of clean energy is less than existent energy in narrow shipfitter maximum effect to source of energy that have Eoteulsu evaluate. There is shortcoming that Blade structure of existent aerogenerator faces at problem of safety accident in overpopulated area and noise and have additional expense of supply of electric power equipment. In this paper, We wish to supplement problem that is such through design of special Blade structure that have noise reduction and stability. Wish to achieve design and simulation of blade to use CATIA for this, and analyze adaptedness of system.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.854-861
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• 1998

The demand of LNG as a cheap and clean energy which does not cause an environmental problem has sharply been increased in Korea. In general LNG is stored in a cargo tank specially designed as a liquid state below $-162^{\circ}C$. The main engine of a LNG carrier is generally a steam boiler because LNG is a highly flammable fluid with the possibility of explosion. The main engine of a cargo ship has to be capable of the propulsion load and various auxiliary loads for the safe navigation since it is the primary energy source. Therefore the evaluation of a main boiler's energy capacity is a key design point in the planning of LNG carrier's construction. This research is to develop the computational program for the analysis of steam boiler Heat balance for LNG carrier.