• 보존과학연구
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• s.32
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• pp.37-52
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• 2011

This study investigates the hardening characteristics of the mixture lacquer and glue at room temperature. Diverse samples were made from manufacturing of glue to the adding ratio in sap of the lacquer tree. After the examination of moisture content of samples, it has been seen that there is no relation with glue's kinds or adding ratio, but only with contain level of moisture. The samples made with film shape in order to examine the drying time. Samples with isinglass needed for over three days and had smooth surface. However, samples mixed with animal glue dried within a day and had ripples on the surface because of fast drying rate. In addition, the samples with isinglass had slow change of colour in early step of drying and no colour difference after completely drying although it had significant changes to black oxide as soon as contact with air. In structural analysis with FT-IR showed that the carbonyl bond increased in the samples of mixed with glue, compared to raw lacquer and treated lacquer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1771-1778
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• 2015

The study aimed to investigate the anti-obesity effects of 1% Rhus verniciflua vinegar (RV) supplementation in high-fat-diet (60% fat)-induced obese rats. A total of 50 4-wk-old male Sprague-Dawley rats were fed normal chow diet or maintained on high-fat diet (HFD) for 12 weeks to induce obesity and were then randomized into five groups as follows: normal diet+ultra-pure water (CON), HFD+ultra-pure water (OB-DW), HFD+1% acetic acid (OBAA), HFD+1% RV (OB-RV), and HFD+0.1% caffeine (OB-CF). AA was used as a control for RV, and caffeine was used as a positive control due to its weight reducing effect. After 2 months, body weight, organ and adipose tissue weights, serum lipids, hepatic lipids, adipocyte size, and cell number per spot level were analyzed. As a result, food efficiency ratio, abdominal adipose tissue weight, serum levels of total cholesterol, triacylglycerol, free fatty acids, coronary artery index, and fecal lipid were significantly reduced in the RV treatment group. In this study, we found that dietary RV improved obesity by increasing lipid excretion and reducing lipogenesis. These results suggest that RV has potential as a functional anti-obesity food.

• Journal of Conservation Science
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• v.32 no.4
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• pp.501-510
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• 2016

In this study, we investigated the degradation of adhesives when exposed to ultraviolet light irradiation using samples of lacquer (L), treated lacquer (TL), lacquer mixed with glue (LG), and urushiol mixed with glue (UG). Four types of film specimens were collected under the ultraviolet exposure time, and gloss test, tensile shear strength test, scanning electron microscope analysis, and infrared spectroscopic analysis were conducted for the specimens. LG and UG showed lowering rate of gloss is somewhat later than L. Also, it was observed that with increasing exposure time to ultraviolet irradiation, the surface of L began to show spherical pits and cracks when the polysaccharide layers started to be exposed, whereas the surfaces of LG and UG remained smooth. The Infrared spectra of L and TL showed that the intensity of the overall peak decreased with increasing ultraviolet irradiation time. There was no change in the peak intensity of LG, but for UG, the peaks at $3013cm^{-1}$, $1593cm^{-1}$ and so on disappeared and the overall intensity declined. The tensile shear strength of LG and UG was maintained or increased as compared to the initial test, whereas the tensile shear strength of L decreased sharply after 600 h. LG and UG exhibited fewer changes as a result of high temperature and humidity conditions, and they retained their strength under UV exposure. These results indicate that LG and UG are more durable than L when subjected to environmental change.

• Journal of Conservation Science
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• v.35 no.5
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• pp.453-469
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• 2019

The celadon jar with inscription of 'the Fourth Sunhwa Year' is an important chronology that shows the conditions of production of the early celadon due to the inscription on the bottom including its purpose, application, and the producer. This celadon jar has been restored several times in the past. However, concerns over the structural stability, such as the separation and level differences in the joined cracks, have risen because of the aging of the repair materials, which were subjected to various environmental changes over a long time. By examining the conditions of preservation, the major damage was identified as the '入' shaped crack on the front, the 'V' shaped restored part and the crack on its left side, and the 'J' shaped crack on the back side. In the past, the cracks were found to be joined using a refined lacquer containing camphor, drying oil, rosin, etc. mixed with soil powder. The joint line was repainted with the refined lacquer and covered with gold powder. The missing parts were restored with gypsum and colored with acrylic color. After that, the repair materials were aged and emergency treatment was performed at the National Museum of Korea in 1981. At that time, Cemedine C or Cemedine C mixed with microballoons was used for reinforcing the cracks. Conservation treatment focused on removing the past repair materials and reinforcing the physically fragile parts by joining and restoring them based on the examination of the preservation condition. in addition, the area around the restored part was colored for future exhibition.

• Journal of Life Science
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• v.19 no.7
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• pp.899-904
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• 2009

We purified crude urushiol from natural lacquer produced in Korea, China, and Japan and then isolated several urushiol congeners known to induce allergic reactions. The 3 major kinds of urushiol congeners that were isolated and purified were RV-l (C$_{21}$H$_{34}$O$_2$, M.W. 314.462), RV-2 ((C$_{21}$H$_{32}$O$_2$, M.W. 316.240) and RV-3 ((C$_{23}$H$_{34}$O$_2$, M.W. 342.515), occupying 80% of total crude urushiol. The content of RV-l was the highest in natural lacquer from China at 70.07%, and was the lowest in that from Japan at 62.38%. However, the content of RV-2 in natural lacquer from Japan was 9.25%, 2$\sim$3 times higher than those from Korea (4.28%) and China (3.09%). As an allergy inducing character, RV-l had strong inducing power and durability in the primary stage, showing slow recovery. RV-2 had weak power in the primary stage and also showed slow recovery. Although RV-3 had comparatively weak power at the primary stage, it induced the strongest allergy contact dermatitis after 48 hr. However, it recovered to nearly the same level as control group 72 hr after sensitization time. Accordingly, we found out that RV-1 is the most influential of urushiol congeners in inducing allergic reactions, natural lacquer from China having the most inducible strength and slowest recovery compared to those from Korea and Japan.

• Journal of Conservation Science
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• v.33 no.5
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• pp.355-362
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• 2017

The Nongso tomb of Sunchang was built in a relatively deep place; hence there was little damage from grave robbers. The tomb was completely filled with a large amount of charcoal, and therefore the wooden coffin was excavated in relatively good condition. On the basis of the structure of the tombs, excavated artifacts, and radiocarbon dating results, the tomb is estimated to be from between the late Goryeo and the early Joseon period. The wooden coffin excavated is double-layered structures consisting of an outer coffin and an inner coffin. The outside of the wooden coffin is thickly lacquered and decorated with yellow letters and white motifs. An analysis of the pigments' components revealed that the major component of the letters was gold (Au) and the major component of the motifs was silver (Ag). The coffin lacquer had three layers: a pigment layer, a yellowish-brown layer, and a black layer. The wooden bases of the coffins were painted with a black substance, such as soot, as mineral elements were not detected in the black layer. The yellowish-brown layer is presumed to be refined lacquer. From the analysis of the structure of the layers and pigments, we can estimate the method was adopted for making lacquer for wooden coffin. It is assumed that the method used gold leaf and gold powder. The form of the pigment and the internal structure are likely to be gold leaf, but the shape of the surface letters appears to have been formed using gold powder. This study will serve as important information for understanding lacquer making techniques at the time of the tombs' construction by confirming the making method through reproduction experiments using gold leaf and gold powder.