• Korean Journal of Materials Research
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• v.19 no.10
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• pp.538-543
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• 2009

Active clays, Diatomite, bentonite and zeolite were used as porous materials for fabricating hygroscopic gypsum boards. Pohang active clay and Cheolwon diatomite showed excellent characteristics of moisture adsorption and desorption. These characteristics were caused by higher surface area and pore volume of porous materials. Moisture adsorption content of gypsum board with 10% active clay(P1) was 62.0 g/m$^2$, and moisture desorption content was 50.2 g/m$^2$. Moisture adsorption content of gypsum board with 10% diatomite(P) was 59.5 g/m$^2$, and moisture desorption content was 49.0 g/m$^2$. Moisture adsorption contents of gypsum boards with porous materials were higher than that moisture desorption contents of gypsum board without porous materials. Correlation coefficient between surface area and moisture adsorption content of gypsum boards was 0.98. Also, correlation coefficient between surface area and moisture desorption content of gypsum boards was 0.97. Moisture adsorption and desorption contents were influenced by surface area and pore volume of the gypsum boards, and surface area had a larger effect on moisture adsorption and desorption.

• KIEAE Journal
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• v.15 no.1
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• pp.45-51
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• 2015

The Purpose of this study is to analyze the green design strategies in residential building, based on case study of Solar Decathlon in USA. This study could provide the basic reference data and theocratical foundation for finding new green design strategies and applicability of green design for korea. The Solar Decathlon is an green design competition that challenges collegiate teams to design, build, and operate the green residential building with optimal energy production and maximum efficiency. As a result of the analysis of this study, the green design strategy is identified and analyzed design issues related in energy, materials, and indoor/outdoor environment. Also, it is useful to find best green design strategy with more economical and environmental benefits presented by renewable energy and design solutions. This study is based on selected 18 green housings of Solar Decathlon from 2002 to 2013. This result is helpful to understand the green design strategies for green residential building's design of modern residential building, and expect future green residential building design approach.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.1-7
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• 2004

The purpose of the study is to review current status of green roof technology and to suggest the issues and solutions related with the technological problems of green roof in Korea. The scope of the study is limited to the extensive green roof which requires low maintenance. Technological issues related with green roof include soil, water proofing, water drain, vegetation and maintenance. Several solutions to invigorate green roof technology were suggested as follows; 1)implementation of technical standard for green roof and technology certification system, 2) development of suitable raw materials for green roof, 3) construction guidelines and uniform construction specification, 4) formulation of city ordinance for green roof, and 5) exchange program with foreign green roof organizations.

• Journal of Information Display
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• v.12 no.3
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• pp.141-144
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• 2011

To improve the performance of blue fluorescent and green phosphorescent organic light-emitting diode devices, Merck developed novel green phosphorescent host and electron-transporting materials. The newly developed electron-transporting material improves the external quantum efficiency of blue fluorescent devices up to 8.7%, with an excellent lifetime. In combination with the newly developed host materials, the efficiency of green phosphorescent devices can be improved by a factor of 1.7, and the lifetime by a factor of 7.

• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.185-189
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• 2007

Various approaches have been proposed to increase the green density. Warm compaction method has been used for the reduction of residual stress, the improvement of magnetic properties and the higher densities. In this work, the effect of warm compaction on green density of Fe powder was investigated. After ball-milling of Fe oxide powder for 30 hours, Fe oxide powder was reduced through the hydrogen reduction process. The pure Fe powder and polymer binder were mixed by 3-D tubular mixer. And then the mixed powder was warm-compacted with various compaction pressure and binder contents. The green density of specimen was added polyvinyl binder was higher than any other specimens.

• Journal of Powder Materials
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• v.19 no.1
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• pp.1-5
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• 2012

In order to improve the remanence of (Nd, Dy)-Fe-B sintered magnets, we investigated the influence of compaction conditions such as packing density, applied field and green density on the magnetic properties. While the remanence decreased with increasing the packing density and green density, it increased with the increase of the applied field. In addition, XRD analysis revealed that the remanence was enhanced as the degree of powder alignment was improved. The green density was more influential on the remanence than the packing density and applied field.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.741-749
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• 1994

The planar solid oxide fuel cell(SOFC) contains several ceramic materials depending on its structure and has rdfractory metal parts for manifolds, shrouds and current leads. Among ceramic materials for planar SOFC, joining of lanthanum chromite separator and yttria stabilized zirconia(YSZ) electoyte in planar SOFC stack to give strong gas tight seals is necessary for satisfactory operation and high performance. Nevertheless, for planar SOFC/sub s/, how to seal the cell stack and gas manifold remains as one of the unsolved problems. Therefore, in this study. we investigated the joining of sintered lanthanum chromite and YSZ pellets using unsintered lanthanum chromite green films as sealent. Scanning electron microscopy(SEM) and energy dispersive X-ray analysis(EDX) revealed that Ca in the sealing material diffused and dissolved into YSZ and sintered lanthanum chromite, and unsintered lanthanum chromite green films reacted with YSZ to from a new phase at the interface. Also, the densification of unsintered lanthanum chromite green films was inpeded by the Ca migration.

• Korean Journal of Metals and Materials
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• v.50 no.3
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• pp.233-236
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• 2012

ZnO nanowires were fabricated through thermal evaporation of Zn or ZnS powder using solar energy. The Zn or ZnS powder was heated and evaporated by sunlight. The sunlight was concentrated on the Zn or ZnS powder by a converging lens and then the Zn or ZnS powder was evaporated and oxidized in air. After oxidation, ZnO nanowires were fabricated in the focal point. Strong ultraviolet emission, which corresponds to the near band-edge emission, was observed from the ZnO nanowires synthesized using Zn powder as a source material. Meanwhile, green emission, related to intrinsic defects such as oxygen vacancies, prevailed for the ZnO nanowires fabricated using ZnS powder. No catalysts were used in the fabrication of the ZnO nanowires, which suggested the ZnO nanowires were grown by a vapor-solid mechanism.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.565-572
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• 2020

This study developed a software platform using machine learning of artificial intelligence to optimize the distillation column system. The distillation column is representative and core process in the petrochemical industry. Process stabilization is difficult due to various operating conditions and continuous process characteristics, and differences in process efficiency occur depending on operator skill. The process control based on the theoretical simulation was used to overcome this problem, but it has a limitation which it can't apply to complex processes and real-time systems. This study aims to develop an empirical simulation model based on machine learning and to suggest an optimal process operation method. The development of empirical simulations involves collecting big data from the actual process, feature extraction through data mining, and representative algorithm for the chemical process. Finally, the platform for the distillation column was developed with verification through a developed model and field tests. Through the developed platform, it is possible to predict the operating parameters and provided optimal operating conditions to achieve efficient process control. This study is the basic study applying the artificial intelligence machine learning technique for the chemical process. After application on a wide variety of processes and it can be utilized to the cornerstone of the smart factory of the industry 4.0.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2041-2043
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• 2013

A layered perovskite of Dion-Jacobson phase, $RbLaTa_2O_7$, was successfully exfoliated into colloidal suspension via successive ion-exchange and intercalation reaction. The pristine perovskite $RbLaTa_2O_7$ was synthesized by conventional solid-state reaction, and then, it was ion-exchanged with hydrochloric acid to obtain a protonic form of perovskite. The resulting proton-exchanged perovskite was reacted with ethylamine to increase interlayer spaces for further intercalation reaction. Finally, the ethylamine-intercalated form was exfoliated into nanosheets via an intercalation of bulky organic cations (tetrabutylammonium). According to X-ray diffraction (XRD) analysis, the TBA-intercalated form showed remarkably increased interlayer spacing (${\Delta}d$ = 1.67 nm) in comparison with that of the pristine material. Transmission electron microscopic image of exfoliated perovskite clearly revealed that the present exfoliated perovskite were composed of very thin layers. This exfoliated perovskite nanosheets could be applicable as building blocks for fabricating functional nanocomposites.