• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.209-215
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• 2017

Fast neutron irradiation was used to improve the switching speed of a 600-V nonpunch-through insulated gate bipolar transistor. Fast neutron irradiation was carried out at 30-MeV energy in doses of $1{\times}10^8n/cm^2$, $1{\times}10^9n/cm^2$, $1{\times}10^{10}n/cm^2$, and $1{\times}10^{11}n/cm^2$. Electrical characteristics such as current-voltage, forward on-state voltage drop, and switching speed of the device were analyzed and compared with those prior to irradiation. The on-state voltage drop of the initial devices prior to irradiation was 2.08 V, which increased to 2.10 V, 2.20 V, 2.3 V, and 2.4 V, respectively, depending on the irradiation dose. This effect arises because of the lattice defects generated by the fast neutrons. In particular, the turnoff delay time was reduced to 92 nanoseconds, 45% of that prior to irradiation, which means there is a substantial improvement in the switching speed of the device.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.777-785
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• 2015

In agricultural systems, significant amount of energy is consumed during irrigation periods. Therefore operating irrigation systems with electrical energy produced by solar energy is very important. It is be possible to operate irrigation systems which have small-pump power like drip-irrigation with electrical energy produced by solar energy. Electrical energy produced by photovoltaic panels can vary from the estimated value due to environmental factors. Consequently analysis of a real system's performance is important. Thus, more correct projections can be made for the systems which will be designed. In this study, induction motor-pump mechanism for drip-irrigation system is operated with photovoltaic generator. Solar energy capacity of the established system is evaluated by measurements in irrigation periods. By means of simulations, power values produced by system and gained from the actual system are compared. Additionally the performance of induction motor is analyzed with the help of the driver system that increases the efficiency and controls the motor. As regards of results, design values of the drip-irrigation systems fed with solar energy in Southeastern Anatolian Regions of Turkey are obtained. Performance results of induction motor controlled with driver are also provided.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1354-1359
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• 2014

A survey is carried out for the future energy sources to be used for ship's propulsion and ship's machinery and operations. 44 global experts from Korea, America, Norway, Denmark, Japan and German who are currently working in the shipyard and offshore fields participated at the survey. Quantitative predications on the market shares of various energy sources, such as oil, LNG, fuel cell, wind energy, solar energy and nuclear energy are made. MPI (market prediction index) is considered as a quantitative index for easy comparison between future's energy sources used for ship's propulsion and operations. It is expected that the MPI of LNG becomes twofold in 2020 against 'before 2016'. It could be also said that hydrogen based fuel cell is expected to increase rapidly for the coming years unless a new alternative energy appears.

• Journal of the Korean Ceramic Society
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• v.43 no.10 s.293
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• pp.607-612
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• 2006

In VARTM (Vacuum Assisted Resin Transfer Molding) process, the permeability generally controls the filling time of the resin and it also affects the void characteristics of the fiber composite. In this study, carbon and glass fiber inter-layered hybrid composites (carbon fiber centered stack) with an epoxy matrix were fabricated by VARTM process and evaluated the resin flow and macro void characteristics. The permeability of glass fiber was higher than that of carbon fiber used in this study. Using Darcy's equation, the permeability of hybrid composites could be predicted and experimentally confirmed. After curing, the macro void content of hybrid composites was investigated using image analyzer. The calculated filling time was well agreed with experimental result and the void content was significantly changed in hybrid composites.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.41-50
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• 2021

The purpose of this study is to analyze various energy platforms using data in the US and to suggest directions and implications. Some of the leading energy platforms are selected and analyzed based on the opening platform model. We focus on the case analysis of the US utility companies. In case of the horizontal open platform, Green Button sponsor's 'Connect My Data (CMD)' driven by the government invites the utility companies to jointly develop the sponsor's data solution. In case of the vertical open platform, the certification program 'Share My Data (SMD)' allows backward compatibility, because the technical improvement is minimal. The utility companies benchmark Amazon's three-sided market mediation and prefer platform and category exclusivity. For the former, they have data analytics companies like Enervee, Opower and for the latter, they have electronics manufactures and energy service providers (ESPs) like Distributed Energy Resources (DERs). Based on this US case study, we suggest the energy platforms to open their platform for renewable energy supply, energy conservation, high-efficiency products, and residential DER dissemination. To successfully implement the government's energy transition policy, the US platforms should be benchmarked as a business model. Especially, it is needed for them to coordinate a platform ecosystem. To ensure trust in the products and services offered on the marketplace platform, platform's certification program is helpful.

• Journal of the Korean Professional Engineers Association
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• v.35 no.4
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• pp.52-55
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• 2002

The development of environment-friendly Energy Resources (New Renewable Energy Resources) is one of the global topics these days, considering CO2 Reduction Agreement by Kyoto Protect and the limit of Conventional Energy Resources in near future. Among the New Renewable Energy, Wind Energy is the most feasible Renewable Energy in view of economical and technical aspect at this moment. Last 10 years the Wind Energy Development was really dramatical in Europe. especially in Germany, Denmark and Spain. In this circumstance World Wind Energy Conference was held in Berlin Germany, in order to review the present status and future development of the Wind Energy. This report is a brief report of the Conference .

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.27-34
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• 2012

Today the energy consumption of ICT networks is about 10% of the worldwide power consumption and will be remarkably increased in the near future. For that reason, the energy saving topics of ICT networks are actually studying in various research institutes. This paper studies the possible energy saving methods assuring the QoS of networks on network level. This paper assumed the energy consumption models according to energy profiles of node and link in IP networks. Especially it formulates the energy problem of a minimum energy consumption with various energy profile models and suggests the methods of energy-aware QoS routing under energy saving and network QoS sustaining condition. It shows the large difference of energy saving according to energy profiles and the possibility of energy saving by using the appropriate energy profile model in the simulation experiment. This paper shows that min_used_path(MP) heuristic of energy-aware QoS routing is the excellent method compared with other heuristic methods as view of reduction ratio of nodes and links and energy saving effect under network QoS sustaining condition. As a result, this paper confirms that the min_used_path(MP) heuristic of energy-aware QoS routing can get energy saving and sustaining of network QoS in IP networks.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.413-420
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• 2004

The current state and future prospects of ultra high energy cosmic ray physics are reviewed. These cosmic rays with energies well above $10^{18}$ eV are messengers of an unknown extremely high-energy universe.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.269.1-269
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• 2002

• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.31-38
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• 2015

It is important to improve the energy performance in the industrial sector, and therefore most of the manufacturing companies need the energy performance indicators to identify the target and to verify the energy savings. However, the conventional energy performance indicators such as the total energy consumption and the energy intensity are not proper to use. The reason is that they do not consider adequate relevant variables including productions in the boundary of the manufacturing companies. Therefore, the study provides the advanced energy performance indicator using by the linear regression model according to each energy source to manage the target and to verify the energy performance properly.