• International Journal of Concrete Structures and Materials
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• v.9 no.2
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• pp.207-217
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• 2015

The influence of powdered and colloidal nano-silica (NS) on the mechanical properties of cement mortar has been investigated. Powdered-NS (~40 nm) was synthesized by employing the sol-gel method and compared with commercially available colloidal NS (~20 nm). SEM and XRD studies revealed that the powdered-NS is non-agglomerated and amorphous, while colloidal-NS is agglomerated in nature. Further, these nanoparticles were incorporated into cement mortar for evaluating compressive strength, gel/space ratio, portlandite quantification, C-S-H quantification and chloride diffusion. Approximately, 27 and 37 % enhancement in compressive strength was observed using colloidal and powdered-NS, respectively, whereas the same was up to 19 % only when silica fume was used. Gel/space ratio was also determined on the basis of degree of hydration of cement mortar and it increases linearly with the compressive strength. Furthermore, DTG results revealed that lime consumption capacity of powdered-NS is significantly higher than colloidal-NS, which results in the formation of additional calcium-silicate-hydrate (C-S-H). Chloride penetration studies revealed that the powdered-NS significantly reduces the ingress of chloride ion as the microstructure is considerably improved by incorporating into cement mortar.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.30.2-31
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• 2020

We present the properties of circumnuclear gas associated with the AGN located in the center of Abell 1644-South. A1644-S is the main cluster in a merging system, which is also known for gas sloshing in its core as seen in X-ray. The X-ray emission of A1644-S shows a rapidly declining profile, indicating the presence of cooling gas flow. This flow of cool gas may fuel the supermassive black hole embedded in the brightest cluster galaxy, leading to the activation of the central AGN. Indeed, we find a parsec-scale bipolar jet feature in the center of A1644-S in our recent KaVA observation, which implies that its central AGN is likely to have been (re)powered quite recently. In order to verify the hypothesis that cooling gas flow in the cluster core can (re)activate the central AGN, we probe the cold gas properties of the central 1 kpc region of A1644-S using the archival VLA and ALMA data. Based on the spatially resolved morphology and kinematics of HI and CO gas, we challenge to identify inflow/outflow gas streams and clumps. We study the role of circumnuclear cool gas in fueling the centrally located cluster AGN in the cool-core environment. We also discuss how the feedback due to the (re)powered AGN affects the surrounding medium.

• Journal of architectural history
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• v.20 no.6
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• pp.131-146
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• 2011

The purpose of this study is to understand the architectural space of Chimjeon (寢殿), the King's Bedroom, and Backyard, in the early Joseon Dynasty. The Royal palace can be divided into three parts, political space for King, living space for King and his family and government office. So first, we should to understand the characteristics of each space in the Royal Palace. Up to now we have looked at the architectural space of the King's Bedroom in the central area and Backyard in Gyeongbokgung (景福宮), one of the Royal Palace, the result of this study is as followings. Cheonchujeon (千秋殿) and Manchunjeon (萬春殿) were not both sides of Sajeongjeon (思政殿), were on the north side of Gangnyeongjeon (康寧殿) Gangnyeongjeon was not a bedroom for the King and Queen, only for King. Bedroom for Queen was located another space in the Royal palace. There was Hamwonjeon on the west side of Koytaejeon. Jamidang and Cheongyeonroo were on the right side of Koytaejeon The Backyard on the north side of Gyeongbokgung had a wide area for horseback archery and the practice of battle formation The arrangement of the King's bedroom in the central area was assumed like as the Fig 7. and Fig 8.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.48-48
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• 2004

• Proceedings of the KSRS Conference
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• v.2
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• pp.752-755
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• 2006

Evaportranspiration is an important factor in hydrology cycle. Traditionally, it is measured by using basin or empirical formula with meteorology data, while it does not represent the evaportranspiration over a regional area. With the advent of improved remote sensing technology, it becomes a surface parameter of research interest in the field of remote sensing. Airborne and satellite imagery are utilized in this study. The high resolution airborne images include visible, near infrared, and thermal infrared bands and the satellite images are acquired by MODIS. Surface heat fluxes such as latent heat flux and sensible heat flux are estimate by using airborne and satellite images with surface meteorological measurements. We develop a new method to estimate the evaportranspiration over the rice paddy. The surface heat fluxes are initialized with a surface energy balance concept and iterated for convergent solution with atmospheric correct functions associated with aerodynamic resistance of heat transport. Furthermore, we redistribute the total net energy into sensible heat and latent heat fluxes. The result reveals that radiation and evaporation controlled extremes can be properly decided with both airborne and satellite images. The correlation coefficient of latent heat flux and sensible heat flux with corresponding in situ observations are 0.66 and 0.76, respectively. The relative root mean squared errors (RMSEs) for latent heat flux and sensible heat flux are 97.81 $(W/m^2)$ and 124.33 $(W/m^2)$, respectively. It is also shown that the newly developed retrieval scheme performs well when it is tested by using MODIS date.

• Journal of the Korean Institute of Rural Architecture
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• v.19 no.3
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• pp.25-32
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• 2017

This study aims to explore the direction of readjustment of rural areas, considering the community. Therefore, it classified the types of 37 Myeon units from 4 communities with higher aging index among rural communities in Jeonnam according to the degree of central functions and population and examined the residents' awareness of community space. As a result, The space used as a social activity for each type is as follows. First of all, the type of decline in the decline of the central index, which reduces transportation conditions, is welfare center (culture center). Second, the central index is high, but there is a low degree of access to the center of the middle and low levels of the population, and the local autonomous center and marketplace, respectively. Third, the low level of access to the central index and the higher center is Nonghyup. Fourth, the decline type with low center index and low accessibility to superior center and low population was the elderly community. Additionally, the types with higher center index on the awareness of community included solidarity and neighbor relationship, and those with lower center index were influenced by cooperation and community awareness for community activation.

• Bulletin of the Korean Space Science Society
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• 1997.04a
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• pp.33.1-33
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• 1997

No Abstract.See Full-text

• Journal of Cadastre & Land InformatiX
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• v.46 no.1
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• pp.75-86
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• 2016

This study examines the social issues between the central and local governments related with the underground space after happenings of sinkholes in Jamsil area in July, 2014. In this study, we consider the keyword network of the social network analysis as a research methodology. The social issues regarding the underground space have been dealt with through the analysis of the centrality and group density to know the attributes of the network. The results show that the government has been steadily helpful to the local governments for establishing the socialized law for the underground space. This research suggests that the laws and technologies as to the underground space issues cooperate each other in the future. It also shows that the government should enact the policies and the national plans for the development of the underground.

• Korean Institute of Interior Design Journal
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• no.29
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• pp.281-288
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• 2001

It shows 21st century as a networking society that is moving up the concept of global town and being industrialized with regional and personal connections. Individual's original idea and variety of 21th century may be respected by such environmental change, and age (Literary, human axis, technology axis, nature axis, kaining farming axis are central keyword) of culture that cultural capacity of individual becomes important fetters that create added value is forecasted to become. The moaning for space that is unemployment enemy by change of conceptional environment about cultural life and agreeable quality of life by development of Information-Communication technology may be required newly. As it does interaction along with development of science technique and Information-Communication technology, the future environment of various that complex! Is predicted to form network environment (existence space, cyberspace) newly. Human central interest is risen in technology balance hereupon, and these characteristic escaped in physical system that do with functional special quality and require human central and sensitive interaction. First, if examine about phenomenon by Digitize and chance aspect that is risen in 21th century, Digitize is time that action occurs fusion Tuesday that is various and Blur phenomenon of city·space, and the period to collapse the border between several individual. Second, importance more than man-centered and sensitive aspect of functional physical system is risen by digital age with development of technology medium, and as the five digital senses showed up, it suggests a sensual of the times and therefore the interest and direction get set up for the sensual sides of consumers. Third, special quality is, medium enemy by that digital space connotes meaning disk floret, variability, transparency, space red of extensity etc.. to burn and is digitalised, can be risen by symbolic, original individualities and emotional communication's the importance is required sensitivity enemy who is sympathy horn by fusion anger of individual. Technology of new media may open direction of new communication through interface that did not enjoy so far is going to supply new means that can express own to human

• Journal of The Korean Astronomical Society
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• v.42 no.3
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• pp.39-45
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• 2009

We investigate the degeneracy in the pattern of central microlensing perturbations of a pair of planetary systems where the planets are located from the primary with projected separations in units of the Einstein radius s and $s^{-1}$, respectively. From this, we confirm the fact that although alike, the patterns of central perturbations induced by a close (s < 1) planet and a wide (s > 1) planet are not identical and the degree of difference depends on the planet/primary mass ratio and the planet-primary separation. We find that the difference can be greater than 5% for planetary systems with lensing parameters located in the parameter space of (1/1.8 < |s| < 1.8, q > $5{\times}10^{-3}$), (1/1.3 < |s| < 1.3, q > $1{\times}10^{-3}$), and (1/1.2 < |s| < 1.2, q > $5{\times}10^{-4}$), where q represents the planet/primary mass ratio. Although this range occupies a small fraction of the entire parameter space of planetary systems, we predict that the chance of resolving the close/wide degeneracy would not be meager considering that the planet detection efficiency is higher for planets with resonant separations (s $\sim$ 1) and heavier masses. We also find that the differences between the perturbation patterns are basically caused by the effect of the planetary caustic. This explains the tendency of the perturbation difference where (1) the difference increases as the planet/primary mass ratio increases and the separation approaches the Einstein radius, (2) the region of major difference is confined within the region around the line connecting the central and the planetary caustics, and (3) a wide (close) planetary system has a more extended central perturbation region toward the (opposite) direction of the planet.