• Journal of the Korean Magnetics Society
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• v.24 no.2
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• pp.46-50
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• 2014

The crystallographic properties and cationic distribution of $M_{0.2}Fe_{2.8}O_4$ (M =Mn, Ni, Cu) and $Fe_3O_4$ thin films prepared by sol-gel method have been investigated by X-ray diffraction (XRD) and conversion electron M$\ddot{o}$ssbauer spectroscopy (CEMS). The ionic valence, preferred site, and hyperfine field of Fe ions of the ferrites could be obtained by analyzing the CEMS spectra. The $M_{0.2}Fe_{2.8}O_4$ films were found to maintain cubic spinel structure as in $Fe_3O_4$ with the lattice constant slightly decreased for Ni substitution and increased for Mn and Cu substitution from that of $Fe_3O_4$. Analyses on the CEMS data indicate that $Mn^{2+}$ and $Ni^{2+}$ ions substitute octahedral $Fe^{2+}$ sites mostly, while $Cu^{2+}$ ions substitute both the octahedral and tetrahedral sites. The observed intensity ratio $A_B/A_A$ of the CEMS subspectra of the samples exhibited difference from the theoretical value. It is interpreted as due to the effect of the M substitution for A and B on the Debye temperature of the site. The relative line-broadening of the B-site CEMS subspectra can be explained by the dispersion of magnetic hyperfine fields due to random distribution of M cations in the B sites.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.5
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• pp.410-419
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• 2009

Generally, air pollutant emission at workplace is estimated by two methods: indirect methods using emission factors and direct methods based on CEMS (Continuous Emission Monitoring System). CAPSS (Clean Air Policy Support System) is a representative indirect method and the national air pollutant database of Korea. However, characteristics of some workplaces may create a gap between CAPSS and CEMS data. For improving of emission data accuracy, emission data of CEMS (named CleanSYS) equipped at 138 target workplaces were compared with those of CAPSS. As a result, $SO_x$ and $PM_{10}$ emission levels obtained by CAPSS were lower than those of CleanSYS. $SO_x$ and $PM_{10}$emission ratios were 61.5% and 71.2% lower respectively, showing the biggest gaps. On the other hand, $NO_x$ emission of CAPSS was higher by 10.4%. $SO_x$ showed the biggest difference in 'Energy industry combustion' and $NO_x$ did in 'Production Process' within the SCC category. $PM_{10}$ presented a large gap in 'Manufacturing industry combustion.' The differences in $SO_x$ between the two systems occurred because some large-size facilities lack pollution controllers or efficient pollution controllers. Based on this study, CAPSS emission database of Korea will improve accuracy through adopting CEMS emission system, which enables more efficient national atmospheric policies and workplace management.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.393-398
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• 2015

City or Community-scale Energy Management System(CEMS) is used to reduce the total energy consumed in the city by arranging the energy resources efficiently at the planning stage and controlling them economically at the operating stage. Of the operational functions of the CEMS, generation forecasting of renewable energy resources is an essential feature for the effective supply scheduling. This is because it can develop daily operating schedules of controllable generators in the city (e.g. diesel turbine, micro-gas turbine, ESS, CHP and so on) in order to minimize the inflow of the external power supply system, considering the amount of power generated by the uncontrollable renewable energy resources. This paper is written to introduce numerical models for photo-voltaic power generation prediction based on the weather forecasting information. Unlike the conventional methods using the average radiation or average utilization rate, the proposed models are developed for CEMS applications using the realtime weather forecast information provided by the National Weather Service.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.482-493
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• 2014

Many kinds of carbon emission monitoring systems or integrated systems have been developed so far. However, despite of the development of related techniques, they tend to be lack of statistic processing functions for feedback and policy-making data for users. In this study, a new CEMS (Carbon Emission Monitoring System) has been suggested and implemented in Sejong City, Korea. This system adapted automatic remote reading system from the site management agency as data hub to collect the electricity, gas and water usage of each household. The CEMS is consisted of 6 parts; carbon emission measurement, carbon emission standard setup and management, statistic analysis and the incentives. CEMS is distinguished with other systems for its UIs for users and the administrators. Also, data sharing with urban information system(UIS) of local government to produce information for users and policy-makers. This system makes it possible to investigate the change of energy consumption patterns, especially depending on the family structure and the housing characteristics. Furthermore, analyzing their correlation with carbon emission, it is expected to provide basic data used to establish urban environmental policies.

• KIEAE Journal
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• v.13 no.6
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• pp.55-65
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• 2013

Korean Government has developed Sejong City as a new administration city. This city of future was planned and designed toward one of the most eco-friendly city on the basis of ICTs. To attain this object, a carbon emission monitoring system (CEMS) was designed and installed as a part of u-city service which provides various information anytime and anywhere to enrich the people's quality of life. In this paper, at first, the structure and functions of CEMS are introduced. This system is consist of 5 parts - data collection from user and linked public DBs, transforming data into meaningful information for the policy makers, system-user interfacing via statistical tables and graphs, and system maintenance. This system can be operated by the citizen participation through whole the process. With the help of GIS map and graphic interface, statistics of monitored data for both citizen and decision maker provided and after feed-back, they have affected on the behaviour of citizen's energy consumption and related policy as well. By the CEMS, energy consumption data of 124 agreed households were collected during 9 months in 2012. Electricity, gas and water consumption were remote-metered automatically by the system and analysed. This showed that more than 85% of CO2 emission is rely on electricity usage. Furthermore, number of family members and size of house influences on the emission of CO2 by each household together with the life-style of the occupants. Electricity and water consumption showed the seasonal factor while gas consumption represents the number of family members. Even this paper has limitations caused by 9 months of data collection, it shows the policy directions to reduce the emission of CO2 focusing on the house size and number of family members of each households. With the result of this research, life-style of the generation of dwellers should be investigated and the CO2 emission characteristics of other housing type as well for the data building for future policy making.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.1-5
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• 2006

The crystallographic properties and cation distribution of oxyspinels ferrite $Co_xFe_{1-x}O_4$ thin films have been explored by X-ray diffraction, vibrating sample magnetometer (VSM), and conversion electron $M\"{o}ssbauer$ spectroscopy (CEMS). Thin films are prepared by sol-gel method. Normal spinel structure is transformed to inverse spinel structure with increasing Co concentration CEMS results indicate that most of $Fe^{3+}$ ions are substituted to $Co^{3+}$ions. Accordingly $Co^{2+}$ ions on octahedral site migrate to tetrahedral site. Magnetic moment is decreased with increasing Co concentration, which means high spin $Fe^{3+}$ ions are replaced by low spin $Co^{3+}$.

• Proceedings of the Korean Magnestics Society Conference
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• 2014.05a
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• pp.85-85
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• 2014

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.19-23
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• 2008

The mixed ferrite $V_xFe_{3-x}O_4$(x=0.0, 0.15, 0.5, 1.0) thin films were prepared by sol-gel method. Their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and conversion electron $M\"{o}ssbauer$ spectroscopy(CEMS). The crystal structure is found to be cubic spinel throughout the series($x{\leq}1.0$), and the lattice parameter $a_0$ increases linearly with increasing V content. XRD, XSP and CEMS indicate that $V^{3+}$ substitution for $Fe^{3+}$ in B-site is superior to $V^{2+}$ substitution for $Fe^{2+}$ in B-site. It is noticeable that both quadrupole shift and hyperfine field decreases with increasing V composition, suggesting the change of local symmetry and accompanying line-broadening. The line-broadening on CEMS spectra can be explained by the distribution of magnetic hyperfine fields.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.163-163
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• 2013

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.18-22
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• 2006

Effects of V substitution of Fe on the magnetic properties of $Fe_3O_4$ have been investigated by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), conversion electron Mossbauer spectroscopy (CEMS), and vibrating sample magnetometry (VSM) measurements on sol-gel-grown films. XRD data indicates that the $V_xFe_{3-x}O_4$ films maintain cubic structure up to x=1.0 with little change of the lattice constant. Analyses on V 2p and Fe 2p levels of the XPS data indicate that V exist as $V^{3+}$ mostly in the $V_xFe_{3-x}O_4$ films with the density of $V^{2+}$ ions increasing with increasing V content. Analyses on the CEMS data indicate that $V^{3+}$ ions substitute tetrahedral $Fe^{3+}$ sites mostly, while $V^{2+}$ ions octahedral $Fe^{2+}$ sites. Results of room-temperature VSM measurements on the films reveal that the saturation magnetization for the x=0.14 sample is larger than that of $Fe_3O_4$, while it becomes smaller than that of $Fe_3O_4$ for $x{\geq}0.5$. The coercivity of the $V_xFe_{3-x}O_4$ films is found to increase with x, attributed to the increase of anisotropy by the substitution of $V^{2+}(d^3)$ ions into the octahedral sites.