• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.481-492
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• 2005

The purpose of this study is to determine geochemical characteristics for stream sediments in the Gwangju area. We collect the stream sediments samples by wet sieving along the primary channels and dry these samples slowly in the laboratory and grind to under 200mesh using an alumina mortar fur chemical analysis. Major elements, trace and rare earth elements are determined by XRF, ICP-AES and NAA analysis methods. For geochemical characteristics on geological groups of stream sediments, we separate geologic groups which are derived from Precambrian granite gneiss area, Jurassic granite area and Cretaceous Hwasun andesite area. Contents range of major elements for stream sediments in the Gwangju area are $SiO_2\;51.89\~70.63\;wt.\%,\;Al_2O-3\;12.91\~21.95\;wt.\%,\;Fe_2O_3\;3.22\~9.89\;wt.\%,\;K_2O\;1.85\~4.49\;wt.\%,\;MgO\;0.68\~2.90\;wt.\%,\;Na_2O\;0.48\~2.34\;wt.\%,\;CaO\;0.42\~6.72\;wt.\%,\;TiO_2\;0.53\~l.32\;wt.\%,\;P_2O_5\;0.06\~0.51\;wt.\%\;and\;MnO\;0.05\~0.69\;wt.\%.$ According to the AMF diagram for stream sediments and rocks, the stream sediments are plotted on boundary of tholeiitic series and calk alkaline series, which shows that contents of $Fe_2O_3$ are higher in stream sediments than rocks. According to variation diagram of $SiO_2$ versus $(K_2O+Na_2O),$ stream sediments are plotted on subalkaline series. Contents range of trace and rare earth elements for stream sediments in the Gwangiu area are Ba$590\~2170$ppm, Be1\~2.4$ppm, Cu$13\~79$ppm, Nb$20\~34$ppm, Ni$10\~50$ppm, Pb$17\~30$ppm, Sr$70\~1025$ ppm, V$42\~135$ppm, Zr$45\~171$ppm, Li$19\~77$ppm, Co$4.3\~19.3$ppm, Cr$28\~131$ppm, Cs$3.1\~17.6$ppm, Hf$5\~27.6$ppm, Rb$388\~202$ppm, Sb$0.2\~l.2$ ppm, Sc$6.4\~17$ppm, Zn$47\~389$ppm, Pa$8.8\~68.8$ppm, Ce$62\~272$ppm, Eu$1\~2.7$ppm and Yb$0.9\~6$ppm.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.83-91
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• 2019

The purpose of this study is to assess a fire-damaged concrete structure using a digital camera and image processing software. To simulate it, mortar and paste samples of W/C=0.5(general strength) and 0.3(high strength) were put into an electric furnace and simulated from $100^{\circ}C$ to $1000^{\circ}C$. Here, the paste was processed into a powder to measure CIELAB chromaticity, and the samples were taken with a digital camera. The RGB chromaticity was measured by color intensity analyzer software. As a result, the residual compressive strength of W/C=0.5 and 0.3 was 87.2 % and 86.7 % at the heating temperature of $400^{\circ}C$. However there was a sudden decrease in strength at the temperature above $500^{\circ}C$, while the residual compressive strength of W/C=0.5 and 0.3 was 55.2 % and 51.9 % of residual strength. At the temperature $700^{\circ}C$ or higher, W/C=0.5 and W/C=0.3 show 26.3% and 27.8% of residual strength, so that the durability of the structure could not be secured. The results of $L^*a^*b$ color analysis show that $b^*$ increases rapidly after $700^{\circ}C$. It is analyzed that the intensity of yellow becomes strong after $700^{\circ}C$. Further, the RGB analysis found that the histogram kurtosis and frequency of Red and Green increases after $700^{\circ}C$. It is analyzed that number of Red and Green pixels are increased. Therefore, it is deemed possible to estimate the degree of damage by checking the change in yellow($b^*$ or R+G) when analyzing the chromaticity of the fire-damaged concrete structures.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.242-281
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• 2010

There are a large number of Buddhist cultural relics in Mt. Namsan. The cultural relics carry the spirit of people of Shila who dream of Buddhist Elysium and the establishment of Buddhist nation. In the valley and the top of the mountain and on various rock cliff, stone statues of Buddha and stone pagodas stand in harmony with nature. For that reason, Mt. Namsan is called an open-air museum. And it played an important role in establishing 'The UNESCO World Heritage' status for Gyeongdju in December 2000. But sadly, there are many stone relics that have eroded away and damaged from collapsing in the passage of time. The seated stone statue of Buddha in Samreoung valley of Mt. Namsan is one of them. It was created between the 8th and 9th century, and restored without much care nor extensive historical research in 1923. As a result, The face of the Buddha remained with concrete mortar and its nimbus fallen backward and destroyed. Therefore, restoration and repair as well as creation of a statue environment for the statue were urgent. So we immediately started in restoration and repair. First, through the archaeological excavation around the stone Buddha, we carried the stone Buddha on the original position. In order to restore the statues to its original glory created by the Unified Shila Dynasty, we created a restoration plan in corporation with art historians and historians, then restored the jaw and the damage nimbus. Second, we made the weathering & damage map of the stone Buddha. In order to prevent second damage, we cleaned the surface of contaminants with distilled water. Third, we studied restoration method to prevent artificial damage. We recreated parts of his face and halo. Then each parts of the statue were restored to their original position. In the whole process of restoration, we tried to use traditional techniques.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.74-93
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• 2019

The Bird Track Site in the Haman Formation in Yongsanri (Natural Monument No. 222) was reported on the named Koreanaornis hamanensis and Jindongornipes kimi sauropod footprint Brontopodus and ichnospecies Ochlichnus formed by Nematoda. This site has outstanding academic value because it is where the second-highest number of bird tracks have been reported in the world. However, only 25% of the site remains after being designated a natural monument in 1969. This is due to artificial damage caused by worldwide fame and quarrying for flat stone used in Korean floor heating systems. The Haman Formation, including this fossil site, has lithofacies showing reddish-grey siltstone and black shale, alternately. The boundary of the two rocks is progressive, and sedimentary structures like ripple marks and sun cracks can clearly be found. This site was divided into seven formations according to sedimentary sequences and structures. The results of a nondestructive deterioration evaluation showed that chemical and biological damage rates were very low for all formations. Also, physical damage displayed low rates with 0.49% on exfoliation, 0.04% on blistering, 0.28% on break-out; however, the joint crack index was high, 6.20. Additionally, efflorescence was observed on outcrops at the backside and the northwestern side. Physical properties measured by an indirect ultrasonic analysis were found to be moderately weathered (MW). Above all, the southeastern side was much fresher, though some areas around the column of protection facility appeared more weathered. Furthermore, five kinds of discontinuity surface can be found at this site, with the bedding plane showing the higher share. There is the possibility of toppling failure occurring at this site but stable on plane and wedge failure by means of stereographic projection. We concluded that the overall level of deterioration and stability were relatively fine. However, continuous monitoring and conservation treatment and management should be performed as situations such as the physicochemical weathering of the fossil layer, and the efflorescence of the mortar adjoining the protection facility's column appear to be challenging to control.

• Journal of Life Science
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• v.29 no.10
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• pp.1062-1070
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• 2019

A components of garlic (Allium sativum) have anti-proliferative effects against various types of cancer. We aimed to investigate the capacity of garlic compounds to anti-tumor on a various cancer cell lines. Fractionation of garlic extract, guided by antiproliferative activity against human gastric cancer (AGS) cells, has resulted in the isolation of N-benzyl-N-methyldecan-1-amine (NBNMA). We investigated the effect of newly isolated NBNMA from garlic cloves on the inhibition of the growth of CT-26, AGS, HepG2, HCT-116, MCF7, B16F10, and Sarcoma-180 cells for in vitro and CT-26 colon carcinoma cells in vivo. NBNMA exhibited an antiproliferative effect in CT-26 cells by apoptotic cell death. NBNMA exhibited down-regulation of anti-apoptotic Bcl-2 proteins and up-regulation of apoptotic Bad protein expression in western blot analyses. In addition, NBNMA meagre activated caspase 3 and caspase 9, initiator caspases of the extrinsic and intrinsic pathways of apoptosis. NBNMA treatment at a dose of 10 mg/kg for 21 days in experimental mice implanted with tumors resulted in significant reduction of the tumor weight (43%). NBNMA exhibited both in vitro and in vivo anticancer activity. These results indicate that NBNMA has promising potential to become a novel anticancer agent from garlic cloves for the treatment of colon carcinoma cancer.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.588-593
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• 2022

Terephthalaldehyde (TPA) is introduced as a cross liker to enhance electron transfer of hemin-based cathodic catalyst consisting of polyethyleneimine (PEI), carbon nanotube (CNT) for hydrogen peroxide reduction reaction (HPRR). In the cyclic voltammetry (CV) test with 10 mM H₂O₂ in phosphate buffer solution (pH 7.4), the current density for HPRR of the suggested catalyst (CNT/PEI/hemin/PEI/TPA) shows 0.2813 mA cm^-2 (at 0.2 V vs. Ag/AgCl), which is 2.43 and 1.87 times of non-cross-linked (CNT/PEI/hemin/PEI) and conventional cross liker (glutaraldehyde, GA) used catalyst (CNT/PEI/hemin/PEI/GA), respectively. In the case of onset potential for HPRR, that of CNT/PEI/hemin/PEI/TPA is observed at 0.544 V, while those of CNT/PEI/hemin/PEI and CNT/PEI/hemin/PEI/GA are 0.511 and 0.471 V, respectively. These results indicate that TPA plays a role in facilitating electron transfer between the electrodes and substrates due to the π-conjugated cross-linking bonds, whereas conventional GA cross-linker increases the overpotential by interrupting electron and mass transfer. Electrochemical impedance spectroscopy (EIS) results also display the same tendency. The charge transfer resistance (R_ct) of CNT/PEI/hemin/PEI/TPA decreases about 6.2% from that of CNT/PEI/hemin/PEI, while CNT/PEI/hemin/PEI/GA shows the highest R_ct. The polarization curve using each catalyst also supports the superiority of TPA cross liker. The maximum power density of CNT/PEI/hemin/PEI/TPA (36.34±1.41 μWcm^-2) is significantly higher than those of CNT/PEI/hemin/PEI (27.87±0.95 μWcm^-2) and CNT/PEI/hemin/PEI/GA (25.57±1.32 μWcm^-2), demonstrating again that the cathode using TPA has the best performance in HPRR.