• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.256-258
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• 2009

현재 상용화되어 있는 결정질 태양전지의 경우 높은 실리콘 가격으로 인해 저가격화에 어려움을 격고 있다. 따라서 태양전지 저가화의 한 방법으로 박막태양전지가 주목을 받고 있다. P-I-N 구조의 박막태양전지에서 각 층의 thickness, activation energy, energy bandgap은 고효율 달성을 위한 중요한 요소이다. 본 논문에서는 박막태양전지 p-layer의 가변을 통하여 고효율을 달성하기 위한 simulation을 수행하였다. 가변 조건으로는 thickness $5\sim25nm$, activation energy $0.3\sim0.6$ eV 그리고 energy bandgap $1.6\sim1.8$ eV까지 단계별로 변화시켰다. 최종 simulation 결과 p-layer의 thickness 5nm, activation energy 0.3 eV 그리고 energy bandgap 1.8 eV에서 최고 효율 11.08%를 달성하였다.

• Journal of Radiation Industry
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• v.3 no.1
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• pp.31-37
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• 2009

This paper describes the preparation of manufacturing a new nanocomposite material, which involves adding a multi walled carbon nanotube (MWCNT) to improve thermal characteristics of poly (ethylene-co-vinyl acetate) (EVA). We irradiated the prepared nanocomposites with doses of 50 kGy, 100 kGy and 200 kGy at a dose rate of $5kGy\;hr^{-1}$ and examined their thermal stability, activation energy and crosslink level by using a thermogravimetric analyzer (TGA) and gel fraction experiments. TGA results indicated that the samples with a MWCNT had higher Derivative Thermo Gravimetry (DTG) 2nd peak temperatures than those without a MWCNT. And activation energy of the samples reduced as the absorption dose and the MWCNT content increased. Finally, the gel fraction increased rapidly up to 100 kGy as total absorption dose increased, and then the growth rate of all samples was slowly increased from 100 kGy.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.813-820
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• 2009

A rapid pneumatic transfer system (PTS) for an instrumental neutron activation analysis (INAA) is developed as an automatic irradiation facility involving the measurement of a short half-life nuclide and a delayed neutron counting system. Three new PTS designs with improved functions were constructed at the HANARO research reactor in 2006. The new system is composed of a manual system and an automatic system for both an INAA and a delayed neutron activation analysis (DNAA). The design and basic conception of a modified PTS are described, and the functions of system operation and control, radiation protection and emissions of radioactive gas are improved. In addition, a form of capsule transportation of these systems is tested. The experimental results pertaining to the irradiation characteristics with variation of the neutron flux and the temperature of the irradiation position with the irradiation time are presented, as is an analysis of the reference material for analytical quality control and uncertainty assessments.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.81-87
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• 2003

Latex polymers are widely used for adhesive, binder, paint etc. Especially the PVAc(Polyvinyl acetate) latex which manufactured by vinyl acetate and vinyl alcohol as protective colloid is a useful environmentally friendly adhesive. To increase useful property of PVAc latex, this study was carried out for checking thermal characteristics and physical condition of PVAc latex by DSC, FT-IR, Pyrolyzer GC-MS. The activation energies of thermal decomposition for 40, 48, 56, 64% solid content of PVAc latex were found as 28.1-36.0kcal/mol by Kissinger's method and 17.2-22.0kcal/mol by DSC method. Actually, reasonable solid content could be consiered as 56% because of activation energy and adhesive characteristics. According to the effect of protective colloid for 4, 10, 15, 20wt%, the activation energy shows same tendency to both method and in case of l5wt% has been found as the highest activation energy. The mechanism of thermal decomposition was mainly estimated by main chain scission, not by side group on FT-IR analysis. Main component of Pyrolzer GC-MS result were consisted of $CH_3COOH$, $CH_3$, $H_2O$ and light gases(CO, $CO_2$, $CH_4$ etc).

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4226-4230
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• 2022

The Korea Atomic Energy Research Institute (KAERI) has designed a Hybrid-Low Power Research Reactor (H-LPRR) which can be used for critical assembly and conventional research reactor as well. It is an open tank-in-pool type research reactor (Thermal Power: 50 kW_th) of which the most important applications are Neutron Activation Analysis (NAA), Radioisotope (RI) production, education and training. There are eight irradiation holes on the edge of the reactor core: IR (6 holes for RI production) and NA (2 holes for NAA) holes. In order to quantify the elemental concentration in target samples through the Instrumental Neutron Activation Analysis (INAA), it is necessary to measure neutron spectrum parameters such as thermal neutron flux, the deviation from the ideal 1/E epithermal neutron flux distribution (α), and the thermal-to-epithermal neutron flux ratio (f) for the irradiation holes. In this study, the MCNP6.1 code and FORTRAN 90 language are applied to determine the parameters for the two irradiation holes (NA-SW and NA-NW) in H-LPRR, and in particular its α and f parameters are compared to values of other research reactors. The results confirmed that the neutron irradiation holes in H-LPRR are designed to be sufficiently applied to neutron activation analysis, and its performance is comparable to that of foreign research reactors including the TRIGA MARK II.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.9-16
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• 2017

Hydrogen forms metal hydrides with some metals and alloys leading to solid-state storage under moderate temperature and pressure that gives them the safety advantage over the gas and liquid storage methods. However, it has disadvantages of slow hydrogen adsorption-desorption time and low thermal conductivity. To improve characteristics of metal hydrides, it is important that activation and thermal conductivity of metal hydrides are improved. In this study, we have been investigated hydrogen storage properties of Hydralloy C among Ti-Mn alloys. Also, the characteristics of activation and thermal conductivity of Hydralloy C were enhanced to improve kinetics of hydrogen adsorption-desorption. As physical activation method, PHEM (planetary high energy mill) was performed in Ar or $H_2$ atmosphere. Hydralloy C was also activated by $TiCl_3$ catalyst. To improve thermal conductivity, various types of ENG (expanded natural graphite) were used. The prepared samples were compacted at pressure of 500 bar. As a result, the activation properties of $H_2$ PHEM treated Hydralloy C was better than the other activation methods. Also, the amounts of hydrogen storage showed up to 1.6 wt%. When flake type ENG was added to Hydralloy C, thermal conductivity and hydrogen storage properties were improved.

• Journal of Energy Engineering
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• v.13 no.2
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• pp.166-172
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• 2004

The activated carbon was produced from Sancheong bamboo by steam and carbon dioxide gas activation methods. The carbonization of raw material was conducted at 90$0^{\circ}C$ and gas activation reactions were conducted with respect to various conditions. -activation temperature 750-90$0^{\circ}C$, the flow rate of steam 0.5-2g-$H_2O$/g-char$.$hr, the flow rate of carbon dioxide 5-30$m\ell$-$CO_2$/g-char-min and activation time 1-5 hr. The prepared activated carbons were measured yield, the adsorption capacity of iodine and methylene blue, BET specific surface area and pore size distribution. The adsorption capacity of iodine (680.5-1526.1 mg/g) and methylene blue (18.3-221.5 mg/g) increased with creasing activation temperature and activation time. The adsorption capacity of iodine and methylene blue increased with the activation gas quantity in the range of 0.5-1.5g-$H_2O$/g-charㆍhr, 5-18.9$m\ell$-Co$_2$/g-charㆍmin. But those decreased over those range due to the pore shrinkage. The steam activation method was superior in efficiency to carbon dioxide activation method.

• New & Renewable Energy
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• v.17 no.2
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• pp.9-23
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• 2021

In Korea, various community investment renewable project models are being implemented to increase community acceptance of renewable energy. An important factor for enhancing local acceptance is that renewable energy projects have a positive effect on revitalizing the local economy such as income increase or job creation for residents and local companies. To maximize the local economic effect of large-scale community investment renewable energy projects, this study developed an evaluation index for local economy activation, whose indicators are the local return on investment, local companies' participation, local job creation, regional cooperation, transparency, and governance. Analysis of existing evaluation indicators and current renewable projects, financial analysis, and expert interviews were used in this research. The pilot evaluation determined that, the local economic effect was high in the following order: a fund investment wind project (Gangwon), benefit-sharing wind project (Jeju), and general wind project. In particular, residents' investment amount, the number of participating residents, and the amount and transparency of the regional cooperation fund were key factors to expand the effect of local economy activation. This evaluation index could be used in public bidding for renewable energy projects such as offshore wind zoning areas of local government.

• Journal of Powder Materials
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• v.20 no.5
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• pp.332-337
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• 2013

Recently, self-propagating high-temperature synthesis (SHS), related to metallic and ceramic powder interactions, has attracted huge interest from more and more researchers, because it can provide an attractive, energy-efficient approach to the synthesis of simple and complex materials. The adiabatic temperature $T_{ad}$ and apparent activation energy analysis of different thermit systems plays an important role in thermodynamic studies on combustion synthesis. After establishing and verifying a mathematic calculation program for predicting adiabatic temperatures, based on the thermodynamic theory of combustion synthesis systems, the adiabatic temperatures of the NiO/Al aluminothermic system during self-propagating high-temperature synthesis were investigated. The effect of a diluting agent additive fraction on combustion velocity was studied. According to the simulation and experimental results, the apparent activation energy was estimated using the Arrhenius diagram of $ln(v/T_{ad}){\sim}/T_{ad}$ based on the combustion equation given by Merzhanov et al. When the temperature exceeds the boiling point of aluminum (2,790 K), the apparent activation energy of the NiO/Al aluminothermic system is $64{\pm}14$ kJ/mol. In contrast, below 2,790 K, the apparent activation energy is $189{\pm}15$ kJ/mol. The process of combustion contributed to the mass-transference of aluminum reactant of the burning compacts. The reliability of the simulation results was experimentally verified.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.227-233
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• 1998

The effects of 1 mol% N-benzylpyrazinium hexafluoroantimonate(BPH) as a thermal latent initiator and blend compositions composed of cycloaliphatic and DGEBA epoxies were investigated in the rheological properties and cure kinetics. Latent properties were performed by measurement of the conversion as a function of reaction time using isothermal DSC at $150^{\circ}C$ and $50^{\circ}C$ Rheological properties of the blend systems were investigated in terms of isothermal experiments using a rheometer. The gelation time was obtained from the evaluation of storage modulus (G'), loss modulus (G") and damping factor (tan$\delta$)). Cross-linking activation energy ($E_c$) was also determined from the Arrhenius equation based on gel time and curing temperature. As a result, the gel time and cross-linking activation energy increased with increasing DGEBA composition. The cure activation energies ($E_a$) were obtained by Kissinger method using dynamic DSC thermograms. In this work, the cure activation energy decreased with increasing CAE concentration, which might be resulted from the short repeat units, simple side-groups and viscosity of reaction media.edia.