• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.86-91
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• 2002

This study introduces a method that selects equipments, so as to reach the reliability level, carrying out an optimization analysis which considers the reliability data and cost of the equipments. A more practical optimization problem has been formed using the object function based on the discrete function and the constraints. The jacked reactor being the subject, an optimization analysis was performed on equipments that have different failure rates depending on costs in order to reach the target reliability level required by the system. The mixed-integer programming (MIP) was used for this optimization analysis. When the jacked reactors target level of reliability was $1.65{\times}10^{-4}$, the result of the analysis showed the equipments with high cost and low failure rate were selected. However when the target level of reliability was low, the result showed that by choosing the equipments with lower cost and reliability over the more expensive one, the desired target level could be reached.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.867-876
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• 2013

To promote the carbon emission trading scheme and reduce greenhouse gas (GHG) emission as following 'Korean GHG & Energy Target Management System', GHG emissions should be accurately determined in each industrial sector. For the estimation method of GHG emission from waste landfill, there are several error parameters, therefore we reviewed the estimation method and proposed a revised method. Methane generation from landfill must be calculated by the selected method based on methane recovery rate, 0.75. However, this methodology is not considered about uncertainty factor. So it is desirable that $CH_4$ generation is estimated using first order decay model and methane recovery should use field monitoring data. If not, $CH_4$ recovery could be applied from other study results; 0.60 of operational landfill with gas vent and flaring system, 0.65 of operational site with landfill gas recovery system, 0.90 of closed landfill with final cover. Other parameters such as degradable organic carbon (DOC) and fraction of DOC decompose ($DOC_f$) need to derive the default value from studies to reflect a Korean waste status. Proper application of MCF that is selected by operation and management of landfill requires more precise criteria.

• Journal of Climate Change Research
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• v.9 no.2
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• pp.181-195
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• 2018

On December 12, 2015, the Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC) adopted the Paris Agreement, in which several developed and developing countries all committed to participating in the reduction of greenhouse-gas (GHG) emissions. South Korea has submitted an intended nationally determined contribution (INDC) proposal with a target to cut down 37% greenhouse gas business as usual (BAU) until 2030 in preparation for the 2030 GHG BAU. Under the post-2020 regime, which will be launched from 2021 as the agreement entered into force early, it is expected that efforts to support GHG reduction and adaptation to climate change in developing countries will be accelerated with the utilization of technologies and financial resources of developed countries. South Korea has established the Basic Plan for Climate Change Response and the Basic National Roadmap for Greenhouse Gas Reductions by 2030 to promote the response to climate change at the government level. The Ministry of Science and ICT, as the National Designated Entity designated by the UNFCCC, has come up with middle and long-term strategies for climate technology cooperation. South-Korea has an abundance of energy-consuming industries to support its export-oriented industrial structure; it is thus expected that achieving the GHG reduction target will incur a considerable cost. Moreover, in order to meet the reduction target (11.3%) of the intended nationally determined contribution proposed by South Korea, it is necessary for South Korea to actively promote projects that can achieve GHG reduction achievements, and financial resources are needed as leverage to reduce risks that can occur in the early stages of projects and attract private sector investment. This paper summarizes the theoretical discussions on climate finance and conducted a comparative analysis on the status of the funds related to climate change response in the UK, Germany, Japan and Denmark. Through this, we proposed the legal and policy tasks that should be carried forward to raise public funds that can be used for creation of new industries related to climate change as well as to reduce GHG emissions in South Korea. The Climate Change Countermeasures Act, which has been proposed by the National Assembly of South-Korea, stipulates the establishment of funds but there is no additional funding except for general account. In this regard, it is also possible to take measures such as the introduction of carbon tax or the collection and use of royalties through technology research and development projects for climate change, such as Industrial Technology Innovation Promotion Act. In addition, since funds are used in various fields such as domestic greenhouse gas reduction, technology development, and overseas projects, it is necessary to establish a system in which various ministries cooperate with the operation of the fund.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.739-745
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• 2003

In $N_{x}$ films were deposited on soda-lime glass without substrate heating by reactive dc magnetron sputtering using indium (In) metal target. Depositions were carried out under various total gas pressures ( $P_{tot}$) of mixture gases (Ar+$N_2$ or He+$N_2$). He gas was introduced to $N_2$ gas in order to enhance the reactivity of nitrogen on film surface by the "penning ionization". Plasma impedance decreased greatly when 20% or more introduced the $N_2$ gas. This is due to the In $N_{x}$ layers formed on target surface because a secondary electron emission rate of InN is small compared with In metal. XRD patterns of the films revealed that <001> preferred oriented polycrystalline In $N_{x}$ films, where the crystallinity of the films was improved with decrease of $P_{tot}$ and with increase of $N_2$ flow ratio. The improvement of the crystallinity and stoichimetry of the In $N_{x}$ films were considered to be caused by an increase in the activated nitrogen radicals and also by an increase in the kinetic energy of sputtered In atoms arriving at growing film surface, which should enhance the chemical reaction and surface migration on the growing film surface, respectively. Furthermore, the films deposited using mixture gases of He+$N_2$ showed higher crystallinity compared with the film deposited by the mixture gases of Ar+$N_2$.$.EX>.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.667-676
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• 2013

This study analyzed the energy demand, greenhouse gas emission and greenhouse gas reduction potential of Electronic Electrical components company. The LEAP model targeting long term energy plan was used to establish the most efficient plan for the companies by examining the climate change policy of government and the countermeasures by companies. A scenario was created by having 11 greenhouse gases reduction plans to be introduced from 2011 as the basic plan. Regarding input data, energy consumption by business place and by use, number of employee from 2009 to 2012, land area and change in number of business places were utilized. The study result suggested that approximately 13,800 TJ of energy will be spent in 2020, which is more than 2 times of 2012 energy consumption. When the integrated scenario based on the reduction plan of companies would be enforced, approximately 3,000 TJ will be reduced in 2020. The emission of greenhouse gases until 2020 was forecasted as approximately 760,000 ton $CO_2eq$. When the integrated scenario would be enforced, the emission will be approximately 610,000 ton $CO_2eq$, which is decrease by approximately 150,000 ton $CO_2eq$. This study will help the efficient responding of eElectronic Electrical components company in preparing detail report on objective management system and enforcement plan. It will also contribute in their image as environment-friendly companies by properly responding to the regulation reinforcement of government and greenhouse gases emission target based on environment policy.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.147-153
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• 1998

Tungsten nitride is very attractive as absorber for X-ray lithographic mask and as a diffusion barrier for interconnecting metallization in Si VLSI technology. Microstructure of tungsten nitride films prepared by RF magnetron sputtering has been investigated as a function of deposition parameter. The crystal structure of sputtered films on silicon nitride membrane depends strongly on the NJAr gas flow ratio(0~18%1, gas pressure(l0~43mTorr). RF power (60~150W), target-substrate distance(4~8cm). Tungsten nitride films deposited at the $N_2/Ar$ gas flow ratio(- 10%). gas pressure(~10mmTorr), RF power(~150W) and target-substrate distance(6cm) are amorphous, but at other conditions are almost rough -surfaced polycrystalline. Amorphous films are very smooth($3.1\AA$ rms) and expected to be excellent absorber for X-ray mask.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.358-361
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• 2012

Co and Ni as catalysts in $SnO_2$ sensors to improve the sensitivity for $CH_4$ gas and $CH_3CH_2CH_3$ gas were coated by a solution reduction method. $SnO_2$ thick films were prepared by a screen-printing method onto $Al_2O_3$ substrates with an electrode. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a chamber. The structural properties of $SnO_2$ with a rutile structure investigated by XRD showed a (110) dominant $SnO_2$ peak. The particle size of the $SnO_2$:Ni powders with Ni at 6 wt% was about 0.1 ${\mu}m$. The $SnO_2$ particles were found to contain many pores according to a SEM analysis. The sensitivity of $SnO_2$-based sensors was measured for 5 ppm of $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air to that in the target gases. The results showed that the best sensitivity of $SnO_2$:Ni and $SnO_2$:Co sensors for $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature was observed in $SnO_2$:Ni sensors coated with 6 wt% Ni. The $SnO_2$:Ni gas sensors showed good selectivity to $CH_4$ gas. The response time and recovery time of the $SnO_2$:Ni gas sensors for the $CH_4$ and $CH_3CH_2CH_3$ gases were 20 seconds and 9 seconds, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1791-1796
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• 2005

Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground between two pits named 'entrance' and 'destination', respectively. Usually a simple composition, such as 'a fiducial target at the entrance+a total station (TS)+a target on the machine', is used to confirm the planned course. However, unavoidable curved sections are present in small-sized pipe lines, which are laid after implementation of a road system, for public works such as waterworks, sewer, electrical power, and gas and communication networks. Therefore, if the planned course has a curved section, it is difficult to survey the course with the abovementioned simple composition. This difficulty could be solved by using the multiple total stations (MTS), which attaches the cross type linear LED target to oneself. The MTS are disposed to where each TS can detect the LED target at the other TS or the base point or the machine. And the accurate relative positions between each MTS and target are calculated from measured data. This research proposes the relative and absolute coordinate calculation algorithm by using three MTS to measure a curved course with 20m curvature at 30m maximum distance, and verifies the algorithm experimentally.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.12
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• pp.1608-1614
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• 1997

The fluidic flow meter detects the gas flow rate based on the principle of fluidic oscillation instead of the conventional displacement method. It has many merits: wide rangeability, no moving mechanical parts and calibration insensitive to physical properties of fluids. The width of nozzle, size of oscillation chamber, size of target, width of outlet are tested to obtain the effects of jet oscillation on the fluidic flow meter. As the width of nozzle is too wide compared with the size of target, jet oscillation is unstable. The oscillation frequency decreases as the distance between the nozzle and target increases and also as the distance between target and outlet contraction increases. Two different vortexes exist in the front and the rear regions of the target, and they affect the oscillation frequency. The outlet contraction is very important, because the feedback flow is generated by the blocking of the flow. As the width of outlet increases, the jet oscillation frequency decreases. The linearity of this tested flow meter is quite good.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.182-189
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• 2018

A neutron generation system was developed to induce fissile fission in a lead slowing down spectrometer (LSDS) system. The source neutron is one of the key factors for LSDS system work. The LSDS was developed to quantify the isotopic contents of fissile materials in spent nuclear fuel and recycled fuel. The source neutron is produced at a multilayered target by the (e,${\gamma}$)(${\gamma}$,n) reaction and slowed down at the lead medium. Activation analysis of the target materials is necessary to estimate the lifetime, durability, and safety of the target system. The CINDER90 code was used for the activation analysis, and it can involve three-dimensional geometry, position dependent neutron flux, and multigroup cross-section libraries. Several sensitivity calculations for a metal target with different geometries, materials, and coolants were done to achieve a high neutron generation rate and a low activation characteristic. Based on the results of the activation analysis, tantalum was chosen as a target material due to its better activation characteristics, and helium gas was suggested as a coolant. In addition, activation in a lead medium was performed. After a distance of 55 cm from the lead surface to the neutron incidence, the neutron intensity dramatically decreased; this result indicates very low activation.