• Journal of the Korean Wood Science and Technology
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• v.49 no.1
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• pp.67-81
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• 2021

This study aimed to conduct tree-ring dating and analysis of the materials used for the wooden coffins excavated from the ruins of Sipjeong-dong, Incheon. The tree species for the 10 wooden coffin materials was identified as pine. For accurate tree-ring measurement, the cross section was polished using sandpaper. The annual ring width was measured with an accuracy of 0.01 mm. Since the five materials were consistent with each other in dendrochronology, a representative annual ring chronology of 83 years was prepared. The prepared representative annual ring chronology was compared with the standard annual ring chronology, and the outermost ring of the wooden coffin was confirmed to correspond to the year 1575, suggesting that the wooden coffin was produced in the late 16th century. In addition, microscopic observation and FT-IR analysis revealed that the fibers attached to the surface of the wooden coffin were fibroin (Silk), and infrared spectroscopy (FT-IR) and Py-GC/MS analysis showed that the paint left on the surface of the wooden coffin was lacquer.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.312-322
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• 2006

The objectives of this study were to evaluate the effect of surface roughness on the surface color and translucency of the composite resins. Two composite resins (Esthet-X, Dentsply, Milford, USA and Charisma, Kulzer, Domagen, Germany) were used to investigate the surface color. Charisma was used to investigate the translucency. 40 disc samples (diameter: 8 mm, thickness: 5 mm) were made by each product to measure the surface color. Polymerized each sample's one side was treated by Sof-Lex finishing and polishing system (Group C, M, F, SF). 40 disc samples (diameter: 6 mm, thickness: 1 mm) were prepared to measure the opacity. 1 mm samples were ground one side with #600, #1000, #1500 and #2000 sandpapers. CIE $L^{*}a^{*}b^{*}$ values of each 5 mm thickness samples, and XYZ values of 1 mm thickness samples on the white and black background were measured with spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Mean surface roughness (Ra) of all samples before and after surface treatment was measured using the Surface Roughness Tester SJ-301 (Mytutoyo, Tokyo, Japan). Regardless of type and shade of the composite resin, $L^{*}$ values measured in group C were higher than others (p < 0.05), and $L^{*}$ value decreased as the Ra value decreased except B3 shade of Esthet-X. But there were no significant difference in $a^{*}$ values among groups. In control group and SF, highest $b^{*}$ values were measured (p < 0.05), except B1 shade of Esthet-X. Contrast ratio decreased as the Ra value decreased (p < 0.05). With the above results, difference of surface roughness has influence on surface color and translucency of dental composite resins.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.195-203
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• 2023

Purpose: This study aimed to evaluate the influence of surface sealants on the surface roughness of composite resins. Materials and Methods: The study used microfilled composite resin (Metafil CX, Sun Medical Co.) and hybrid composite resin (Aelite^TM LS posterior, Bisco). Sixty specimens (8 mm in diameter and 4 mm in height) of each composite resin type were prepared and divided into 3 groups. Each specimen was ground with 600, 1000, and 2000-grit sandpaper. The Surface roughness (Ra) values were measured using a surface roughness tester (SJ-301, Mytutoyo) before and after surface sealant application. Surface sealants, BisCover^TM LV (Bisco), Optiguard^® (Kerr), and Seal-n-Shine^TM (Pulpdent), were applied to the specimens, as instructed and observed by scanning electron microscope (JSM-7500, JEOL) and atomic force microscope (MultiMode IV, Veeco Instruments). Results: Specimens ground with 600-grit sandpaper coated with surface sealants exhibited significantly lower Ra values than the untreated group (P < 0.05). Specimens ground with 1000 and 2000-grit sandpaper showed statistically no difference. There was no significant difference in surface roughness among BisCover^TM LV, Optiguard^®, and Seal-n-Shine^TM. SEM and AFM revealed remarkably decreased microdefects on the surfaces of composite resins after surface sealant application. Conclusion: Surface sealants can influence surface roughness when applied on the rough surface of composite resins but not on highly polished composite resins.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.4
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• pp.7-15
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• 2000

The purpose of this work is to evaluate the solderahility and characteristics of solder joints. Bridge defect of solder joint was examined in natural atmosphere and $N_2$ condition. Consequently, wettability was excellent for each of Sn-Pb plated Cu specimen, Sn plated Cu specimen, and Cu polished in $N_2$ condition. The wetting time in $N_2$ condition was shorter than that of natural atmosphere condition, showing the decreasing values of about 0.2~0.45 seconds. The max. wetting force under the $N_2$ condition was more increasing that of natural atmosphere condition, showing the increasing values of about 1.8~2.8 N. With the result of wetting balance test, the wetting time ($t_2$) and wetting farce according to increasing amount of $N_2$ from 10 1/min to 30 1/min, the wetting time ($t_2$) was reduced about 0.25 second and wetting force was increased about 2.3 N. In non-cleaning flux, when $N_2$ gas is applied, it is compensated to decrease of wettability. In the case of using the $N_2$ gas, the wettability was improved. The reason for improving wettability is due to preventing the formation of dross. The generation rate of bridge in $N_2$ condition decreased than that of natural atmosphere, and when the specimen had a fine pitch, the rate of bridge defects was considerably decreased in $N_2$ condition, showing the decreasing rate of 25~75%.

• Korean Journal of Biological Psychiatry
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• v.4 no.1
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• pp.102-107
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• 1997

Ginseng root, as a folk medicine, has been used in far eastern countries for thousands of years. Ginseng extract has been shown to have a variety of effects on the activity of the central nervous system, promoting stimulation as well as inhibition of the cortical activity. A survey of the relevant literatures has indicated that the putative anxiolytic activity of red ginseng has not been scientifically investigated. Therefore, the present study was designed to assess anxiolytic effect of gingseng total saponins(GTS). The putative anxiolytic effects of several fractions of GTS were investigated in mice using an elevated plus maze paradigm. Single dose administration of TS Fr.-I showed anxiolytic action in mice. Anxiolytic effect induced by TS Fr.-I was similar to that induced by diazepam. TS Fr.-II, TS Fr.-III and TS Fr.-IV did not show the anxiolytic action compared with that of TS Fr.-I. It was suggested that regulation of GABAergic neurotransmission may be important in the action of GTS. The Interaction of GTS fractions with benzodiazepine receptor was performed using rat cortical membranes. GTS inhibited the binding of [3H] Ro 15-1788 on the benzodiazepine receptor. Among from TS fractions, the binding activity of GTS in the TS Fr.-IV was highest, which did not show the anxiolytic activity. From these results, we conclude that GTS has anxiolytic action, and this is not related to benzodiazepine receptor binding activity.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.85-95
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• 2017

This study aimed at more precisely estimating the age of big old trees using dendrochronological method. Gesan-gun in Chungbuk (CBGS), Gurye-gun in Jeonnam (JNGR) and Uljin-gun in Gyeongbuk (GBUJ) were study areas and Zelkova serrata (ZS) and Pinus densiflora (PD) selected as protected trees therein were used as experimental tree species. The increment cores were extracted from 12, 8, and 6 ZSs and 10, 3, and 9 PDs in CBGS, JNGR, and GBUJ, respectively, using an increment borer (${\phi}5.2mm$). In order to clearly distinguish tree-ring boundary, the surface in the transverse section was cut for ZS using a sliding microtome and sanded for PD using a sand paper. Ring widths were measured in the resolution of 0.01 mm. Based on the measurement values, 203-year long (1813-2015) ZS local master tree-ring chronologies were successfully established and 175-year long (1841-2015) ZS local master tree-ring chronology for JNGR was also successfully established. In the case of PD, 154-, 175-, and 250-year long local master tree-ring chronologies for CBGS, JNGR, and GBUJ were successfully established, respectively. In the comparisons between local master tree-ring chronologies, they showed low t-values and Glks. According to the comparisons of the local master tree-ring chronologies with 50-year (1950~2000) average temperature and precipitation distribution maps, the annual variations of local master tree-ring chronologies seem to be determined by not temperature but precipitation. For such cross-dating therefore more local master tree-ring chronologies have to be established at the least based on the distribution map for precipitation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.334-339
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• 2020

In this study, the adhesion properties between aluminum and composite materials, composite materials, and composite materials were compared according to the physical surface treatment to improve mechanical bonding at the bonding surface when considering carbon fiber and glass fiber-reinforced composite materials. Bonded specimens were classified into the type of base material and the surface treatment method of the bonding surface. Sandpaper, sandblasting, and plasma were applied as physical surface treatment methods. The bonded specimen was prepared as a single lap joint test specimen. An experiment to measure the lap shear strength was conducted, and the results were compared. The experimental results confirmed that the mechanical abrasion and sandblasting treatment improved the lap shear strength approximately 4 to 5 fold compared to the general specimen without physical surface treatment. In plasma treatment, the experiment was conducted by defining the respective plasma output and treatment time as follows: 150 W and 5 minutes, 150 W and 10 minutes, and 300 W and 3 minutes. Moreover, the lap shear strength results were similar to the previous mechanical surface treatments. On the other hand, the effect on the adhesion properties was small, depending on the plasma treatment conditions.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.105-109
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• 1982

The effect the physiochemical properties of red and white ginseng powder after $^{60}Co-{\gamma}$ ray irra diationduring the storage for 4 months at $25^{\circ}C$ was investigated. The storage periods and the treatment of irradation at various doses on ginseng powders has no significant effect on the proximate composition and color density of ginseng extract with 50% ethanol. No changes in the contents of saponin and its HPLC patterns were found during the storage. However, a little increase was found in the yield of 50% ethanol extract and Hunter's color value of powder. But generally it was found to be stable in the physicochemical properties of red and white ginseng powder by irradiation of the intensity during the storage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.443-450
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• 2020

This paper reports a design improvement study to solve the stoppage phenomenon caused by the launch-support device applied to K105A1. The K105A1 is a weapon system equipped with an old 105 mm towed howitzer in a wheeled vehicle, which provides superior maneuverability compared to track equipment. The launch support device serves to withstand fire impact and load. In this way, this device is fixed firmly to the ground in preparation for the shooting mission and is responsible for the critical performance, such as fixing the position of the vehicle. On the other hand, during the field test, a temporary stoppage of the launch support occurred, which caused a problem of not being fixed to the ground. To solve this problem, the cause of failure was analyzed by a replay test and parts inspection. In addition, the operating concept, method, and design were analyzed to derive the cause and solve the problem by changing the parts design. Finally, the performance and firing missions were performed normally by applying the changed design to K105A1. The performance stability and reliability of the launch support device were confirmed, which are expected to be of great assistance in the development of military equipment in the future.

• Elastomers and Composites
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• v.46 no.4
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• pp.335-342
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• 2011

The virgin and recycled polyethylene composites with various ratio of fly ash were manufactured by using a fully intermeshing co-rotating twin screw extruder for the reuse of fly ash from power plant and post-consumed polyethylene. Fly ash were blended with virgin HDPE and recycled polyethylene at the weight fraction of 0 to 40 wt.%. Mechanical properties such as yield strength, abrasion resistance, and slow crack resistance were measured with ISO and ASTM standards. The experimental results for the various composites showed that the elongation at break and the yield stress of the composites decreased with increasing fly ash contents. Generally, the abrasion resistance of PEs decreased with increasing sandpaper grits but the abrasion resistance of the composites increased with fly ash content at finer abrasive surface. The slow crack growth resistance of virgin HDPE, recycled JRPE and the JRPE composite showed higher slow crack growth resistance up to 50% of load at notch depth of 20% and 30%, but KRPE and the KRPE composite showed much lower resistance than virgin HDPE, JRPE and the JRPE composite. Time to break, measured with NCLS test method, of all PEs and the composites satisfies the regulation of Korean Industrial Specification for sewer pipe and support application.