• Title/Summary/Keyword: chemical exfoliation

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Deterioration Characteristic Analysis for Stone Properties in the Taereung Royal Tomb of the Joseon Dynasty using Nondestructive Analysis (비파괴 분석을 활용한 조선왕릉 태릉 석조물의 손상특성 분석)

  • Lee, Myeonseong;Choie, Myoungju;Lee, Taejong;Chun, Yungun
    • Korean Journal of Heritage: History & Science
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    • v.53 no.2
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    • pp.222-241
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    • 2020
  • The Taereung Royal Tomb from the Joseon Dynasty is the tomb of Empress Munjeong, the second queen of King Jungjong, and it contains various types of stone artifacts. All of these stone artifacts were constructed using coarse- to medium-grained biotite granite. The major types of deterioration of the stone artifacts are identified as surface weathering and biological contaminants. Exfoliation (145 sculptures), granular decomposition (138 sculptures), and repair materials (156 sculptures), along with biological contaminant algae (154 sculptures), lichen (165 sculptures) and moss (97 sculptures), have a high occurrence frequency. In particular, it is deemed that immediate conservation treatment is required, as biological deterioration (algae) represents the most serious condition (grade 3 or higher in 94% of all stones), and it is thought that exfoliation and granulation decomposition are required for long-term conservation management. As a result of equo -tip hardness and ultrasonic measurement, more than 70% of stones were found to have very weak physical properties. Through hyperspectral analysis, organisms were shown to inhabit more than 80% of the surface of burial mound stone artifacts, and P (phosphorus), S (sulfur), Cl (chlorine), and Ca (calcium) were detected in this area. This is because Taereung Royal Tomb has been exposed to the outdoors for hundreds of years and has been weathered by physical, chemical, and biological factors. Therefore, among the stone artifacts in the Taereung Royal Tomb, those with high physical weathering grades are considered to require consolidation to reinforce them physically. Since organisms are highly likely to cause stone damage, they must be removed via dry and wet cleaning. In addition, in order to delay the reoccurrence of organisms following conservation treatment, it is necessary to regularly clean up the soil that has flowed into the burial mound, and to monitor conservation conditions over the long term.

Material Characteristics and Deterioration Assessment of the Stone Buddhas and Shrine in Unjusa Temple, Hwasun, Korea (화순 운주사 석조불감의 재질특성과 풍화훼손도 평가)

  • Park, Sung-Mi;Lee, Myeong-Seong;Choi, Seok-Won;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.24
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    • pp.23-36
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    • 2008
  • The stone Buddhas and Shrine of Unjusa temple (Korea Treasure No. 797) in Hwasun formed in Koryo Dynasty are unique style which the Buddha faces each other the back parts of south and north within the stone Shrine. The stone Buddhas and Shrine are highly evaluated in historical, artistic and academic respects. But, the stone properties have been exposed in the open system various aspects of degradations weathered for a long time without specific protective facilities. The rock materials of the stone Buddhas and Shrine are about 47 blocks, and total press load is about 56.6 metric ton. The host rocks composed mainly of white grey hyaline lithic tuff and rhyolitic tuff breccia. In addition, biotite granite used as part during the restoration works. The chemical index of alteration for host tuffaceous rocks and the replacement granites range from 52.1 to 59.4 and 50.0 to 51.0, respectively. Weathering types for the stone Buddhas and Shrine were largely divided with physical, chemical and biological weathering to make a synthetic deterioration map according to aspects of damage, and estimate share as compared with surface area. Whole deterioration degrees are represented that physical weathering appeared exfoliation. Chemical weathering is black coloration and biological weathering of grey lichen, which show each lighly deterioration degrees. According to deterioration degree by direction of stone Buddhas and Shrine, physical weathering mostly appeared by 39.1% on the sorthern part, and chemical weathering is 61.2% high share on the western part. Biological weathering showed 38.3% the largest distribution on the southern part. Therefore, it is necessary to try hardening for the parts with serious cracks or exfoliations, remove secondary contaminants and organisms through regular cleaning. Also necessary to make a plan to remove moisture of the ground which causes weathering, and estimate that need established and scientific processing through clinical demonstration of conservation plan that chooses suitable treatment.

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Testicular Toxicity of 2-Bromopropane in Male Sprague-Dawley Rats (2-Bromopropane의 수컷 랫트를 이용한 고환 독성시험)

  • Cha, Sang-Eun;Park, Sang-Rae;Kim, Kgu-Hwan;Choi, Jeung-Suk;Kim, Sung-Kuk;Jeon, Tae-Won
    • Environmental Analysis Health and Toxicology
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    • v.15 no.4
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    • pp.123-130
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    • 2000
  • 2-Bromopropane, important industrial chemical, specially in electronic industry at Yangsan in Korea has been reported to cause amenorrhea for female and azoospermia, oligozoospermia or reduced sperm motility for male. 2-BP was investigated through 21 days of repeated dose in male Sprague-Dawley rats. The dose levels per body weight were 0 (control), 250,500 and 1,000 mg/kg. 2-BP dissolved in vehicle olive oil was injected into the intraperitoneum 6 times per week for 3 weeks, but 1,000 mg/kg dose group was 2 weeks because of serious illness. Male rats showed significant decreases in body weight and right and left testis showed typical weight losses depending on the 2-BP. The number of white blood cell and red blood cell , percentage of monocytes, and hemoglobin decreased significantly in high dose (P< 0.05). Red cell volume distribution width increased significantly in the high dose (P< 0.05). Histopathological findings of testes showed a decrease of spermatogenic cells, exfoliation of spermatid and spermatocyte, vacuolization of Sertoli cells and hyperplasia of Leydig cells. Protein band density between 113,000 dalton ($\beta$-galactosidase) and 53,900 dalton (ovalbumin) has decreased in 250 mg/kg dose group, but it has gradually increased to the higher density in 1,000 mg/kg dose group than in control group.

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Applied Mineralogy for the Conservation of Dinosaur Tracks in the Goseong Interchange Area (35번 고속도로 고성 교차로 지역 공룡발자국의 보존을 위한 응용광물학적 연구)

  • Jeong Gi Young;Kim Soo Jin
    • Journal of the Mineralogical Society of Korea
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    • v.17 no.3
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    • pp.189-199
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    • 2004
  • Cretaceous sedimentary rocks bearing dinosaur tracks in the Goseong interchange area were studied for their conservation and public display in the aspect of applied mineralogy. Black clay layers alternate with silt layers in the sedimentary rocks. The verical and horizontal fissures are commonly filled with calcite veinlets, supergenetic iron and manganese oxides. The rocks are composed of quartz, albite, K-feldspar, calcite, chlorite, illite, muscovite, and biotite, with minor apatite and rutile. Silt layers are relatively rich in calcite and albite, whereas clay layers are abundant in quartz, illite, and chlorite. Al, Fe, Mg, K, Ti, and P are enriched in the clay layers, while Ca, Na, and Mn in silt. Most of trace elements including V, Cr, Co, Ni, Cs, Zr, REE, Th, and U are enriched in clay layers. Inorganic carbon are present in silt layers as calcite, while organic carbon in black clay layers. The black clay layers were partly altered to yellow clay layers along the fissures, simultaneously with the decrease of organic carbon. Selective exfoliation of clay-rich black and yellow clay layers, calcite matrix of silt layers and calcite infillings of fissures are estimated as the major weakness potentially promoting chemical and physical degradation of the track-bearing rock specimens.

Development of High Performance Curing Agent and Effective Dispersion Method of Nanomaterials (고성능 피막양생제 개발 및 나노물질의 분산방안 평가)

  • Son, Ho-Jung;Yoo, Byung-Hyun;Lee, Dong-Gyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.230-236
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    • 2019
  • Recently, issues related to the quality of concrete have continuously resulted in surface quality problems, such as the exfoliation of concrete surfaces due to the cost reduction of cement and poor quality fine aggregate, scaling of surfaces caused by laitance, and plastic shrinkage cracks. Prompted by social issues, the application of a photo catalyst to road structures is being attempted to solve the environmental problems caused by fine dust and automobile exhaust. In this study, chemical admixtures were developed to improve the surface quality of concrete and to apply and distribute titanium dioxide in nanoscale sizes to provide basic data for the development of a photocatalyst-curing agent. As a result of the experiment, silicon and silane were reviewed as a raw material as a curing agent to develop a high performance curing agent with better film performance than conventional curing agents because they could form a film quickly on a fresh concrete surface. The distributed stability of the ultrasonic disperser showed the best performance through an outdoor test for four weeks to review the dispersion measures for the application of nanomaterials.

The Cycling Performance of Graphite Electrode Coated with Tin Oxide for Lithium Ion Battery (리튬이온전지용 주석산화물이 도포된 흑연전극의 싸이클 성능)

  • Kang, Tae-Hyuk;Kim, Hyung-Sun;Cho, Won-Il;Cho, Byung-Won;Ju, Jeh-Beck
    • Journal of the Korean Electrochemical Society
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    • v.5 no.2
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    • pp.52-56
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    • 2002
  • Tin oxide was coated on graphite particle by sol-gel method and an electrode with this material having microcrystalline structure for lithium ion battery was obtained by heat treatment in the range $400-600^{\circ}C$. The content of tin oxide was controlled within the range of $2.25wt\%\~11.1wt\%$. The discharge capacity increased with the content of tin oxide and also initial irreversible capacity increased. The discharge capacity of tin oxide electrode showed more than 350 mAh/g at the initial cycle and 300 mAh/g after the 30th cycle in propylene carbonate(PC) based electrolyte whereas graphite electrode without surface modification showed 140 mAh/g. When the charge and discharge rate was changed from C/5 to C/2, The discharge capacity of tin oxide and graphite electrode showed $92\%\;and\;77\%$ of initial capacity, respectively. It has been considered that such an enhancement of electrode characteristics was caused because lithium $oxide(Li_2O)$ passive film formed from the reaction between tin oxide and lithium ion prevented the exfoliation of graphite electrode and also reduced tin enhanced the electrical conduction between graphite particles to improve the current distribution of electrode.

Effect of Epidermal Changes in the Mice Skin Following Glycolic Acid Peeling (글리콜산을 사용한 화학적 필링이 Mice 피부 표피에 미치는 영향)

  • Lee, Jee-Yean;Lee, Suk-Jun;Chang, Byung-Soo
    • Applied Microscopy
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    • v.40 no.4
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    • pp.245-251
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    • 2010
  • In this study, we applied 15% glycolic acid peeling agent and 30% glycolic acid peeling agent to the dorsal skin of mice and analyzed the oil content, moisture content, and pH value of the skin before and after test using cutometer. Ultrastructure for changes in the epidermis of mice were observed under a dermoscope and a scanning electron microscope before and after test. When using 15% glycolic acid peeling agent, the changes of moisture content was measured 74.67 AU for the normal control group and 70.21 AU for the experimental group, the oil content was 13.49 mg/$cm^2$ for the normal control group before test and 8.25 mg/$cm^2$ after test, and the pH value was 6.70 and 5.36 before and after test, respectively. When using 30% glycolic acid peeling agent, the moisture content was measured 74.46 AU for the normal control group before test and 53.50 AU for the experimental group after test, the oil content was 13.82mg/$cm^2$ and 5.70 mg/$cm^2$ before and after test, and the pH value was 6.45 and 4.58 before and after test, respectively. As such, it was found that the changes of moisture and oil content on the skin rely on the concentration of peeling agent and the degree of exfoliation of keratin. The surface of stratum corneum of mice with application of 15% glycolic acid peeling agent was relatively smooth and the exposed cellular surface of keratinocyte had some wrinkles. The surface of stratum corneum of mice with application of 30% glycolic acid peeling agent was smooth. No wrinkles were observed under high-resolution scanning electron microscope.

Deterioration Analysis and Source Area on Rock Properties of the Seokgatap Pagoda in the Bulguksa Temple, Korea (불국사 석가탑의 풍화훼손도 분석 및 기원암의 산지추정)

  • Lee, Myeong-Seong;Lee, Chan-Hee;Suh, Man-Cheol;Choi, Seok-Won
    • 한국문화재보존과학회:학술대회논문집
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    • 2004.10a
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    • pp.15-24
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    • 2004
  • The Seokgatap pagoda composed of mainly alkali granite and other minor pink-feldspar granite, fine-grained granite, granodiorite, diorite, gabbro, and tuff. Despite the small loss and damage derived from joints, its peel-off and exfoliation are serious enough to cause the heavy deterioration on the stone surface. The chemical and petrological weathering has partly replaced the original rock-forming minerals with clay minerals and iron oxyhydroxides. Based on the petrogenesis, rock materials of the pagoda is very similar to rocks of Dabotap pagoda and the Namsan granite in the Gyeongju. The central fart of the pagoda has sunken highly, which caused all the corners to split and the structural transformation to become worse. The reverse V-shaped gaps between the materials have broken stones filled in a coarse way. The iron plates inserted between the upper flat stone laid on other stones and tile pagoda body in the north and east side has been exposed in the air and corroded, discoloring of the adjacent stones. The overall diagnosis of the Seokgatap pagoda is the deteriorated functions of the stone materials, which calls for a long-term monitoring and plans to reinforce the stone surfaces. But the main body including the pagoda roof stone needs washing on a regular basis, and the many different cracks should be fixed with glue by using the fillers or hardeners designed for stone cultural properties after removing the cement mortar. In case of the replacement of the stone materials with new stones, it's necessary to examine the pagoda for the center of gravity and support intensity of the materials. The structural stability of the pagoda can be attained by taking a reinforce measure in geotechnical engineering and making a drainage. The ground humidity, which has aggravated weathering and structural instability, should be resolved by setting up a humidity reduction facility. The contamination of lichens and bryophyte around the pagoda and on the surface is serious. Thus biochemical treatments should be given too in order to prevent further biological damages and remove the vegetation growing on the discontinuous planes.

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Weathering and Deterioration Diagnosis for Conservation Sciences of Stone Pagoda in the Bunhwangsa Temple,Gyeongju, Korea (경주 분황사 모전석탁의 암석학적 풍화와 보존과학적 훼손도 진단)

  • Yi, Jeong-Eun;Lee, Chan-Hee;Lee, Myeong-Seong;Kim, Young-Taek
    • 한국문화재보존과학회:학술대회논문집
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    • 2004.10a
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    • pp.92-100
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    • 2004
  • The host rocks of brick-shaped stone pagoda in the Bunhwangsa temple are lots of kinds andesitic rocks, which has gone through mechanical and chemical weathering. As the overall observation, the pagoda is serious damages by air pollutants, and the northeast parts show the much advanced state of turning white, while the southeast parts are heavily cracked in the materials. The rocks of brick-shaped pagoda body are in a relatively stable condition of weathering and damage except for the abrasion and cracks of the corners. The rocks of the pagoda roof suffer from more symptoms including multiple peel-offs, exfoliation, cracks forming round lines, and falling off stone pieces. The pagoda roof rocks are dominated by the thriving leafy lichens and mosses, especially, there are higher plants (selaginella involvens, dandelions) taking root actively between the brick stones and content mortar. There are even light gray precipitates like stalactites between the rocks of the body, In particular, the 1st and 2nd floor in the east side and the body parts in the north side are the most serious. Their major minerals are calcite, gypsum and clay minerals. The rocks of the stylobate and the tabernacle in all the four directions are composed mainly of granitic rocks. The materials consisting of the tabernacles show the severe splits and distortion, which causes the structural instability. The stylobate rocks are heavily contaminated by some weeds with the often marks of inorganic contamination by secondary hydroxides. The central part of the east stylobate has been sinking, while that of the 1st floor west stylobate is protruded nesting a line of cracks. Accordingly, the inside of the tabernacle is always humid with the constant introduction of rainwater. The stone lion standing in the southeast and northeast side are alkali granite, while that in the southwest and northwest lithic tuff. Each of the stone lion also coated with various colored lichens, mosses, algae, bacteria and bryophyte. The external materials of the pagoda have deteriorated the functions of the rocks and made the loss, falling off, and biological contamination even worse due to the surface weathering. Thus it's urgent to come up with scientific restoration and conservation measures through clinical tests.

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Source Area of the Rocks Using the West Stone Pagoda of Gameunsaji Temple Site, Korea (감은사지삼층석탑(서탑)에 사용된 석재 공급지에 대한 연구)

  • Jwa, Yong-Joo;Kim, Kun-Ki;Ko, Seok-Bae;Kim, Jong-Sun
    • The Journal of the Petrological Society of Korea
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    • v.15 no.3 s.45
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    • pp.128-138
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    • 2006
  • The west stone pagoda of Gameunssji temple site (National Treasure No. 112) has been damaged mainly by fracture, exfoliation and granular disintegration. In this study, the source area of the rocks using the west stone pagoda was examined in terms of petrological feature, magnetic susceptibility, and ${\gamma}-ray$ spectrometer. The stones include abundant crystal fragments of biotite, quartz and feldspars in the fine-grained matrix; they are petrographically discriminated to vitric-crystal tuff or crystal tuff. Measured magnetic susceptibility values are of from 10 to 20 $({\times}10^{-3}\;SI\;unit)$. From the ${\gamma}-ray$ spectrometer measurement K, eU, and eTh contents of the stones are about 3%, 0 to 8ppm, and 9 to 18 ppm, respectively. These features are used as indicators to presume the source area of the stones. Comparing the petrographical and chemical characteristics between the stones of the west stone pagoda and the country rocks near the Gameunsaji temple site, it is suggested that the most similar country rock to the stones could be dacitic volcanic rocks of the Beomgokri group in the Waeup basin. The Beomgokri group is lithostratigraphically divided into Waeupri tuff, Yongdongri tuff and Beomgokri volcanic rocks. Among the three rocks, the crystal tuff of the Beomgokri volcanic rocks seems likely to have been the source rock of the stones of the west stone pagoda.