• Journal of the Korean Chemical Society
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• v.31 no.3
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• pp.215-224
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• 1987

The electrical conductuctivity measurements have been made on polycrystalline samples of various compositions in the $MgO-TiO_2$ system from 600 to $1100^{\circ}C$ under $Po_2$'s of $10^{-8}\;to\;10^{-1}$atm. Plots of log ${\sigma}$ vs. 1/T at constant $Po_2$ are found to be linear with the inflections, and the activation energies are 1.94eV for the intrinsic range and 0.48eV for the extrinsic range, respectively. The log ${\sigma}$ vs. log $Po_2$ curves are found to be linear at constant temperature, and the conductivity dependences of $Po_2$ are closely approximated by ${\sigma}\;{\alpha}\;Po_2^{-1/6}$ for the extrinsic and ${\sigma}\;{\alpha}\;Po_2^{-1/4}$ for the intrinsic range, respectively. The dominant defects in this system are believed to be oxygen vacancy for the extrinsic and $Ti^{3-}$ interstitial for the intrinsic range. The conduction mechanisms in both the extrinsic and the intrinsic ranges are proposed by the results of the electrical conductivity dependence on the oxygen partial pressure. Polaron model was suggested in the extrinsic region by the conductivity dependences of temperature and $Po_2$.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.406-412
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• 1987

The electrical conductivities of ${\alpha}-Fe_2O_3$ containing 2.5 and 5.0mol% of cadmium were measured from 300 to $900^{\circ}C$ under oxygen pressures of 10$^{-7}$ to 10$^{-1}$ atmosphere. Plots of log ${\sigma}$ vs. 10$^3$/T show the extrinsic conductivity at oxygen pressure higher than $5{\times}10$^{-2}$atm. The transition points appear at about 550$^{\circ}$C and the activation energies are 1.34 eV for the intrinsic region and 0.50 eV for the extrinsic region on 5mol% Cd-doped ${\alpha}-Fe_2O_3$. The extrinsic conductivity disappears at oxygen partial pressures lower than $5{\times}10$^{-2}$ atm, and the intrinsic conductivity predominates. The electrical conductivities decrease with increasing mol% of cadmium doped. The predominant defect of ${\alpha}-Fe_2O_3$ doped with Cd is believed to be Fe${2+}$ interstitial for the intrinsic, however, oxygen vacancy predominates for the extrinsic region. The electrical conduction mechanisms are proposed and the conduction band model is suggested for the extrinsic region.

• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.353-360
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• 2017

The preservation treatment for the outer rampart of Namhansanseong fortress is needed due to partial collapse and separation of stone materials. In this study, we investigated the petrological features of the stone materials used for the outer rampart and estimated their provenances through the geologic survey. Through the above study, the suitable replacement stone in the maintenance of outer rampart were suggested. The stone materials of the above outer rampart consist of the banded gneiss, augen gneiss, granitic gneiss and porphyroblastic gneiss. Among these four kinds of rocks, granitic gneiss is quantitatively the most abundant. Petrological comparisons between stone materials and rocks distributed around the fortress, lead to the conclusion that the above materials are likely to have been delivered from around the fortress. Judging from the results of the comparison on frequency of use and strength characteristics among the above rocks, the granitic gneiss is considered to be suitable for restoration of the outer rampart of the fortress.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.88-96
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• 2015

This purpose of this study was to identify the landscape characteristics of cultural heritage area in Gapgot fortification by performing text analysis of related literature and antique maps. And accumulate modern photograph to investigate the landscape of modern. As a additionally analysis, was examined landscape of Gapgot fortification area using aerial photograph. The results were as follows. First, Gapgot fortification has the historical value as symbolic and practical gateway to Ganghwa island caused by geographical position. And historical culture resources were located in Gapgot fortification area such as through traffic, military facilities. Secondly, According to literature and antique maps, Gapgot fortification area was village and military facilities from Goryeo dynasty. The village and military facilities was expanded with Jinhae pavilion since construct Ganhwa castle. Thirdly, In modern Gapgot fortification area appear consecutive coastal landscape when entry Ganghwa bridge. But, inhibiting elements of landscape should be remedied.

• YAKHAK HOEJI
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• v.42 no.1
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• pp.95-100
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• 1998

Male Sprague-Dawley rats were exposed to the toluene at 3,000${\pm}$200ppm via inhalation for two hours (single inhalation group), three weeks by two hours per day, six days per wee k (repeated inhalation group). We examined the level of excitatory amino acids of the extracellular neurotransmitter within the corpus striatum of rats by using in vivo microdialysis. Aspartate (Asp) and glutamate (Glu) of excitatory amino acid neurotransmitters were generally decreased in the inhalation groups compared with the control group, and more significantly decreased in the repeated inhalation group than in the single inhalation group except that Asp was increased from 60 min after the beginning of the inhalation to 30 min after the termination.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.285-297
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• 1995

Ganoderan, an immunomodulating ${\beta}-glucan$ of G. lucidum, induces potent antitumor immunity in tumor-bearing mice. The present study was set up to elucidate the chemical composition and bioactivities of ganoderan obtained from the mycelial fractionation of G. lucidum IY009. Ganoderan was isolated and purified from its extracellular, cell wall and cytoplasmic sources. These ganoderans were composed mainly of glucose. The cell wall-alkali soluble-water soluble fraction (CW-AS-WS) showed the highest antitumor activity (inhibition rate of 94%) in sarcoma-bearing mice and 37% of anticomplementary activity. The CW-AS-WS fraction was found to be approximately average 20,000 dalton in aq. 0.3N NaOH solution and composed of 88% carbohydrate and 4% protein. The carbohydrate of the CW-AS-WS was composed of 74% glucose. These results indicate that the ganoderans extracted from the mycelial fractionations of G. lucidum IY009 had different chemical characteristics and showed different potentiality in antitumor and anticomplementary activity.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.212-219
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• 1997

Multiple forms of extracellular phospholipase $A_2$ have been detected in human amniotic fluid (HAF). When HAF was subjected to heparin-Sepharose column chromatography, phospholipase $A_2$ activity was detected in both heparin-non binding and binding fraction. The activity of heparin-non binding fraction was further purified by sequential uses of column chromatographies on butyl-Toy-opearl 650M and DEAE-Sephacel. DEAE-Sephacel fraction contained three different phospholipase $A_2$ activities (Peak I, II, III). The molecular weight of DEAE-Sephacel fraction phospholipase $A_2$ determined by SDS-PAGE were about 52KDa (Peak I). Peak II, III required micromolar $Ca^{2+}$ ion for its maximum activity, but Peak I enzyme showed calcium independent phospholipase $A_2$ activity and showed broad range of pH (6.0~10.0) optimum. All these enzymes were not recognized by a monoclonal antibody raised against phospholipase $A_2$ from human synovial fluid. These results suggest that HAF might contain multiple forms of extracellular phospholipase $A_2$, which may neither belong to the 14KDa group II phospholipase $A_2$ family nor cytosolic phospholipase $A_2$.

• The Korean Journal of Mycology
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• v.6 no.2
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• pp.1-10
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• 1978

In de novo biosynthesis of the extracellulor enzymes-proteinsaes, alpha and gluc-amylases during the synchronized differentiation of Aspergillus niger in submerged culture and surface liquid culture were investigated. Gluc-amylase was synthesized in the stage of presporulation in which phialide formation is involved. Proteinase was synthesized both in the stages of conidiophore formation and presporulation. Alpha-amylase was synthesized during presporulation and sporulation stages, the activity of enzyme lasted for seven days on surface liquid culture. It seemed that the synthesis was occured in de novo partly repressed by the catabolite, and its nature was found to be constitutive since it is produced in non-starch medium. Polyacrylamide gel electrophoresis have shown that presporulating and sporulating body produced diverse types of the proteins whereas the earlier stages of vegetative body showed simpler profiles. The uptake of C-14 uracil into RNA and C-14 glutamate into protein were shown to be vigorous in presporulating body rather than those in sporulating body. Coincidence of alpha-amylase biosynthesis in de novo and sporulation may be significant in the study of differentiation in which gene expression is involved.

• Korean Journal of Heritage: History & Science
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• v.52 no.1
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• pp.258-271
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• 2019

Recent changes in inter-Korean relations have encouraged South Korean archaeologists' interest in northern cultural heritage and their desire to conduct research. However, it is doubtful how much the South Korea really knows about the cultural ruins in North Korea and the cultural ruins to be found in the DMZ. In Korea, research data on the Japanese colonial period is scattered amongst national institutions and it is not possible to to collect, identify and document the data available in each institution. Typically, the data of Keiichi Ogawa(小川敬吉) is difficult to understand in its printed from. In addition, Ogawa has collected data from several national government agencies, and work is underway to collect architectural data and construct digital archives. This situation will not occur if we publish the data collected so far in digital form. Therefore, there is an urgent need to fully disclose the data related to Cheolwon which is owned by national institutions. If this data is analyzed, sufficient archaeological information can be obtained without excavation. On the other hand, one must wonder if the whole landscape of Cheolwon castle of Taebongguk cand be understood by investigating the interior of Cheolwon castle. This effort should be preceded by a survey on the ruins and the remains of the southern part of the southern boundary line. Rapid development and large-scale arrangement of cultivated land are likely to make it difficult to restore the external landscape related to the tillage demand that is required by the current situation. In the process of restoration of the actual Gyeongwon Line, it has been confirmed that serious irregularity has caused damage and the landscape has been transformed. In order to minimize these risks, it is urgent that we investigate the relics scattered in the southern part of the country, and not devote ourselves to the investigation of Cheolwon. In this regard, how much military, roads, excavation and archaeologists are prepared, centered on Cheolwon and scenery is an important question. I am curious as to how much preparation is provided to the Chulwon-gun and Gangwon-do in terms of administrative assistance, and how much archaeologists and excavation agencies are aware of the archaeological information of the inside and the southern part of the DMZ. Furthermore, how long have people been aware of the archaeological remains on the North Korean side? In order for da iscussion on Cheolwon and scenery to progress, it is necessary to carry out a precise investigation and accumulation of data on the remains in South Korea.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.38-55
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• 2021

Cherwon Castle is located in Pungcheonwon, Cherwon, in the center of the Korean Peninsula. Currently, it is split across the Demilitarized Zone (DMZ) between the two Koreas. It attracts attention as a symbol of inter-Korean reconciliation and as cultural heritage that serves as data in making important policy decisions on the DMZ. Despite its importance, however, there has not been sufficient investigation and research done on Cherwon Castle. This is due to the difficulty involved in investigation and research and is caused by the site's inaccessibility. As a solution, the current investigative methods in satellite and aerial archeology can be applied to interpret and analyze the structure of Cherwon Castle and the features of its inner space zoning. Cherwon Castle was built on the five flat hills that begin in the northern mountainous hills and stretch to the southwest. The inner and outer walls were built mainly on the hilly ridges, and the palace wall was built surrounding a flat site that was created on the middle hill. For each wall, the sites of the old gates, which were erected in various directions , have been identified. They seem to have been built to fit the direction of buildings in the castle and the features of the terrain. The castle was built in a diamond shape. The old sites of the palace and related buildings and landforms related to water drainage were identified. It was verified that the roads and the gates were built to run from east to west in the palace. In the spaces of the palace and the inner castle, flat sites were created to fit different landforms, and building sites were arranged there. Moreover, the contour of a reservoir that is believed to be the old site of a pond has been found; it lies on the vertical extension of the center line that connects the palace and the inner castle. Between the inner castle and the outer castle, few vestiges of old buildings were found, although many flat sites were discovered. Structurally, Cherwon Castle is rotated about nine degrees to the northeast, forming a planar rectangle. The planar structure derives from the castle design that mimics the hilly landform, and the bending of the southwestern wall also attests to the intention of the architects to avoid the wetland. For now, it is impossible to clearly describe the functions and characters of the building sites inside the castle. However, it is believed that the inner castle was marked out for space for the palace and government offices, while the space between the outer and inner castle was reserved as the living space for ordinary people. The presence of the hilly landform diminishes the possibility that a bangri (grid) zoning system existed. For some of the landforms, orderly zoning cannot be ruled out, as flat areas are commonly seen. As surveys have yet to be conducted on the different castles, the time when the walls were built and how they were constructed cannot be known. Still, the claim to that the castle construction and the structuring of inner spaces were inspired by the surrounding landforms is quite compelling.