• The Journal of Engineering Geology
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• v.11 no.3
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• pp.245-254
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• 2001

The experimental study on disposal cover through the performance test facility offers reliability in the safety of near surface disposal of low and intermediate level radioactive waste. To ensure the long-term safety of the repository, the impermeability, integrity, resistance to degradation and ease of maintenance might be considered as the basic performance requirement of the disposal cover. considering the difficulties to meet these performance requirement by using single layer, the disposal cover design which is composed of top layer, middle drainage layer and bottom low permeability layer is schemed for the test facility. The water balance of the cover was evaluated by using HELP code. For the long-term monitoring of the soil moisture content and matric potential, TDR probes and tensiometers will be installed in 6 test cells. Each test cell is dimensioned 3$\times$3$\times$3.3m.

• Korean Journal of Materials Research
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• v.23 no.2
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• pp.128-134
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• 2013

A study on the corrosion behavior of Inconel alloys and Incoloy 800H in molten salt of LiCl-$Li_2O$ was investigated at $650^{\circ}C$ for 24-312 hours in an oxidation atmosphere. The order of the corrosion rate was Inconel 600 < Inconel 601 < Incoloy 800H < Inconel 690. Inconel 600 showed the best performance suggesting that the content of Fe, Cr and Ni are the important factor for corrosion resistance in hot molten salt oxidation conditions. The corrosion products of Inconel 600 and Inconel 601 were $Cr_2O_3$ and $NiFe_2O_4$, In case of Inconel 690, a single layer of $Cr_2O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2O_4$ and inner layer of $Cr_2O_3$ were formed with an increase of corrosion time. In the case of Incoloy 800H, $Cr_2O_3$ and $FeCr_2O_4$ were observed. Most of the outer scale of the alloys was observed to be spalled from the results of the SEM analysis and the unspalled scale which adhered to the substrate was composed of three layers. The outer layer, the middle one, and the inner one were Fe, Cr, and Ni-rich, respectively. Inconel 600 showed localized corrosion behavior and Inconel 601, 690 and Incoloy 800H showed uniform corrosion behavior. Ni improves the corrosion resistance and too much Cr and/or Fe content deteriorates the corrosion resistance.

• Journal of the Korea Society of Computer and Information
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• v.18 no.6
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• pp.71-79
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• 2013

Metabolic pathway, represented by well-displayed graph, have a complex binding structure, which makes the graphical representation hard to visualize. To apply automatic graph layout techniques to the genome-scale metabolic flow of metabolism domains, it is very important to reduce unnecessary edge crossing on a metabolic pathway layout. we proposed a metabolic pathway layout algorithm based on 3-layer layout. Our algorithm searches any meaningful component existing in a pathway, such as circular components, highly connected nodes, and the components are drawn in middle layer. Then the remaining subgraphs except meaningful components are drawn in upper and lower layer by utilizing a new radial layout algorithm. It reduces ultimately reduced the number of edge crossings. Our algorithm solve the problem that edge crossings exponentially increase as the number of nodes grows.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.129-135
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• 2013

Recently, waste water treatment system is developed in small and middle size to get more economic advantage. Freeze concentration system has high thermodynamic efficiency and low energy consumption, can re-use purified water and cold energy obtained from ice. This study was experimentally performed to investigate pollution containment in frozen layer by cooling wall temperature, air-bubble flow methods, initial ice-lining thickness of frozen layer in NaCl aqueous solution and the representative heavy metals, Pb and Cr aqueous solution. As the result, a decrease in the cooling wall temperature bring a higher growth rate of ice front and the more solute was involved in frozen layer. The method to inject directly air-bubble into ice-liquid interface through ring shape nozzle gave high purity of ice compared to indirect method. Ice lining in 5mm thickness resulted in frozen layer with higher purity than 1mm thickness.

• Korean Journal of Metals and Materials
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• v.48 no.4
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• pp.277-288
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• 2010

The hot corrosion properties of heat-resistant steels were investigated in an oxidation atmosphere including artificial ash and sulfur dioxide. The heat-resistant steels of T22, T92, T122, T347HFG, Super304H and HR3C were evaluated at 620, 670 and $720^{\circ}C$ for 400 hours. The relationship between the corrosion rate and the temperature followed a bell-shaped curve with a peak rate at around $670^{\circ}C$. The corrosion rates showed a decreasing tendency as the chrome contents of these steels increased from 2.15 wt.% to 24.5 wt.%, and austenitic steels had a lower corrosion rate than ferritic steels. Sulfidation by $SO_2$ as well as molten salt corrosion also had an effect on the total corrosion rate, especially showing an increase in the corrosion rate in ferritic steels. Regardless of the chrome content in the steels and irrespective of the test temperature, the corrosion scale was composed of an outer oxide and an artificial ash mixed layer, a middle oxide layer and inner sulfide, and a mixed oxide layer. As the chrome content increased, the proportion of chrome oxide in the corrosion scale increased. Before spalling of the corrosion scale, voids and cracks were initiated in the sulfide and the mixed oxide layer or at the interface with the substrate.

• Restorative Dentistry and Endodontics
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• v.46 no.1
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• pp.11.1-11.11
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• 2021

Objectives: The aim of this study was to compare smear layer removal by conventional application (CA), passive ultrasonic irrigation (PUI), EasyClean (EC), and XP-Endo Finisher (XPF), using 17% ethylenediaminetetraacetic acid (EDTA) after chemomechanical preparation, as evaluated with scanning electron microscopy (SEM). Materials and Methods: Forty-five single-rooted human mandibular premolars were selected for this study. After chemomechanical preparation, the teeth were randomly divided into 5 groups according to the protocol for smear layer removal, as follows: G1 (control): CA of distilled water; G2 (CA): CA of 17% EDTA; G3 (PUI): 17% EDTA activated by PUI; G4 (EC): 17% EDTA activated by EC; and G5 (XPF): 17% EDTA activated by XPF. SEM images (×1,000) were obtained from each root third and scored by 3 examiners. Data were evaluated using the Kruskal-Wallis and Dunn tests (p < 0.05). Results: In the apical third, there were no statistically significant differences among the groups (p > 0.05). In the cervical and middle thirds, the experimental groups performed better than the control group (p < 0.05); however, G2 presented better results than G3, G4, and G5 (p < 0.05), which showed no differences among one another (p > 0.05). Conclusions: No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation.

• Journal of Conservation Science
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• v.26 no.3
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• pp.269-276
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• 2010

This study aims to extract manufacturing techniques by analysing metallurgical characteristics of the cast-iron pot from Bubjusa, examining corrosion status and microstructure with a optical microscope, SEM-EDS, micro vickers hardness tester and XRD. The microstructure analysis has presented that ferrite and partial portion of pearlite exist within the corroded outer layer. The analysis of the inner layer revealed that there is pearlite and graphite of feather shape. The one of the middle layer, which is placed between outer and inner layer, showed that corrosion has been heavily developed. Micro vickers hardness values range from 217Hv to 698Hv in constituent layers and such values lie within the ranges of the ancient iron relics. The result of EDS analysis for each microstructure presented that the outer layer has been more decarbonized than the inner layer. XRD analysis of iron corrosion compound revealed that Goethite and Hematite had been produced from the corrosive process of iron. The study concludes that the large iron pot was made by casting technique, and microstructure of inner layer had a gray cast iron. Outer layer has been decarbonized through repetitive process of heating and cooling. This results can be used as fundamental data for comparative study to reveal manufacturing techniques of large cast-iron pot.

• Journal of Sericultural and Entomological Science
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• v.18 no.1
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• pp.21-26
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• 1976

The study was carried out to investigate the variations in the fibroin hydrolysis of different cocoon shell layers, and the relationship between the hydrolysis and silk physical property. The obtained results are as follows: 1. The fibroin hydrolyzing ratio was highest at the inner layer of cocoon shell and. next in order. at the middle layer and at the outer layer. 2. The fibroin hydrolyzing ratio of abnormal cocoons was higher than normal cocoon and it was different among them, tile highest was double coroon, thin shell cocoon and perforated cocoon in order. 3. The sericin content and fibroin hydrolyzing ratio of Jam 111 and Jam 112 was higher than that of Jam 111 $\times$ Jam 112. 4. The fibroin hydroiyzing ratio of the cocoons fed with the artificial diets was increased at the inner layer. The sericin content of those lessened at the inner layer, however, it slightly increased at the most inner layer more than at the inner layer. 5. The breaking strength of the degummed silk fiber of different cocoon layers was reduced at the inner layer. The breaking Strength of abnormal silk fiber was less than that of normal silk fiber. 6. A negative correlation (r= －0.8) )was approved between fibroin hydrolyzing ratio and breaking strength of silk fiber, and the regression line was Y=－0.29x＋5.07.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.778-784
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• 2008

In this paper, a chip antenna using multi-layer configuration for multi-band operation, such as GSM, DCS, pcs, WCDMA, and Mobile WiMAX for 2.3 GHz is proposed. This proposed antenna is a PIFA structure with multi-layer configuration fabricated on R04003 substrate(${\varepsilon}_r=3.4$) and its size is $22{\times}5.5{\times}4.0\;mm^3$. Multi-layer structure can effectively reduce the size of an antenna from a reuse of air-space and can achieve broad bandwidth due to decrement of parallel capacitances from the insertion air-gap to the middle layer. The proposed antenna has a broadband operation by the high order resonance modes and the resonance at the top layer. The measured bandwidths with over 45 % radiation efficiency are 80 MHz($880{\sim}960\;MHz$) at the lower band and 690 MHz($1,710{\sim}2,400\;MHz$) at the higher band.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.1
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• pp.13-26
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• 2001

Six ferromanganese crusts from the Lomilik and Litatfooki seamounts in the Marshall Islands were analyzed for texture, geochemistry and stratigraphy to delineate the paleoceanographic conditions. The crusts can be divided into three layers; 1) outermost massive layer (Layer 1), 2) middle porous Fe-oxides rich layer infllled with biointemal clasts (Layer 2), and 3) innermost massive layer cemented and/or replaced by carbonate fluoapatite (CFA) (Layer 3). The Layer 1 contains higher Mn, Co, Ni, and Mg than other two layers, and the Layer 2 was relatively more enriched in Fe, Al, Ti, Ba, Cu, and Zn. However, the Layer 3 shows higher Ca and P and lower Mn, Fe, Co, and Ni contents than overlying two layers. Based on the Co-chronometry, the crusts are postulated to have begun to grow from 56-31 Ma (early Eocene to Oligocene). The boundaries between layers 1 and 2, and layers 2 and 3 are dated to be 7-3 Ma and 26-14 Ma, respectively. High contents of Ca and P in Layer 3 clearly indicate that the layer had been phosphatized prior to the formation of Layer 2. Considering the well-preserved mjcrostructures in Layer 3, it is unlike that the crusts themselves were recrystallized in suboxic condition. Also, the lower Co concentrations in Layer 3 may imply that the Co supply was not constant during the formation of Layer 3. Layer 2, characterized by the porous texture, grew over Layer 3 during 26-9 Ma. Internal biogenic sediments including foraminifera within the original cavities and the enrichment of organophillic elements such as Ba, Cu, and Zn, suggest that Layer 2 have below high production regions. Also, high content of allumino silicate components may indicate increased terrigeneous input during the formation of Layer 2. The Layer 2. The Layer 1 has been subjected to little diagenetic influence since the Pliocene.