• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.38-55
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• 2019

The purpose of this study is to clarify the historical flow of baekdong alloy's usage according to the alloying materials mentioned in document records. For this purpose, we first overviewed the use of copper as a base material for white copper alloys and other types of copper alloys. Baekdong is an alloy of copper and other metals and is currently defined as an alloy of copper and nickel. However, depending on the research subjects and time of the scholars, baekdong may be defined as a metal with over a certain percentage of tin added to copper, or as an alloy of tin, zinc, and lead with copper. There is disagreement regarding the interpretation of this term. Baekdong, which started to appear in the literature of the Three Kingdoms Period, has been steadily seen through the Goryeo and Chosun Dynasties to the modern period. It has been used in various ways, according to each age and culture, from the symbol of the office to trading goods, daily life goods, and money. In the literature, baekdong's alloying material is not only copper and nickel, which are currently defined as alloys, but it is the same in that copper is used as the base metal of the alloy, although it varies slightly from generation to generation. In addition to copper, tin, zeolite, and emerald, zinc and lead also appeared. It was found that baekdong, which means alloy, and baekdong, which means white metal, were mixed. Nickel, which is the alloy material of baekdong as it is currently defined, is a metal with a relatively high discovery time and is widely used as a material for modern industrial fields. Nickel was introduced into Korea at the end of the Joseon Dynasty, but its use is not known in detail. In this study, we examined the acceptance and use of nickel-based baekdong in articles of modern newspapers and in statistical data. Based on the experience of craftsmen, we estimated the period when nickel-based alloys were used in crafts. Material is a direct factor in the development and deterioration of technology, and the development of technology is the basis for the changing of civilizations and cultures. In this context, this study was to investigate baekdong with the material of alloys as a starting point.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.103-120
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• 2002

In the Baekdong-Hongseong area, the southwestern part of the Gyeonggi Massif in Korea, ultramafic rocks occur as lenses within Precambrian granitic gneiss. At Baekdong area, ultramafic lens contains metabasite boudin which had undergone at least three stages of metamorphisms. The mineral assemblage on the first stage, Garnet+Sodic Augite+Hornblende+Plagioclase+Titanite, is recognized from the inclusions in garnet. The second stage is represented by the assemblage in matrix, Garnet+ Augite+Hornblende+Plagioclase, while the third stage is identified by the Hornblende+Plagjoclase $\pm$ Garnet assemblage in the symplectite formed around garnet. The P-T conditions of the first and the third stages are $690-780^{\circ}C$, 11.8-15.9 kb and $490-610^{\circ}C$, 4.0-6.3 kb, respectively. These data indicate that metabasite in Baekdong area had experienced a retrouade P-T path from the eclogite(EG) - high-pressure granulite (HG)-amphibolite (AM) transitional facies to the AM through HG-AM transitional facies. The core and rim of garnet in country granitic gneiss give $605-815^{\circ}C$, 10.7-16.0 kb and $575-680^{\circ}C$, 5.4-7.0 kb, respectively, indicating that the retrograde P-T path of granitic gneiss is similar to that of metabasite. Trace element data reveals that the tectonic setting of metabasite is island uc. The general geology, the metamorphic evolution, the mineral chemistry and the tectonic setting of Baekdong area indicate that the Baekdong-Hongseong area in Korea is a possible extension of the Sulu collision Belt in China. On the other hand, the Sm-Nd whole rock-garnet isochron ages of metabasites are 268.7-297.9 Ma which are older than the ages of UHP metamorphism (208-245 Ma) in the Dabie-Sulu Collision Belt. The older metamorphic ages suggest that collision between Sino-Korea and Yangtz plates may have occurred earlier in Korean Peninsula than China.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.157-174
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• 1984

Four different levels of nitrogen were applied to 3 naked barley cultivars (Hordeum vulgare L.) Yonezawa, Baekdong and Yeongsanbori. Changes in chlorophyll content, green leaf area and light penetration were monitored after heading. Yield and its components were examined upon these changes. Increased level of N-application delayed the days to heading and ripening by 2-3 and 6-7 days, respectively, in Yonezawa. Yonezawa with a short culm was more resistant to lodging than two tall ones (Baekdong, Yeongsanbori) under heavy nitrogen applications. Yield was affected mostly by the number of spikes per unit area and 1, 000 grain weight at all levels of N-applications. The increase in dry weight of Baekdong was more than in that of Yonezawa. A sharp increase in dry weight was observed after 3 weeks of heading. Maximum yield was obtained at $N_2$ in Yonezawa (234kg/10a) and Baekdong (302kg/10a) and at $N_1$ in Yeongsanbori (332kg/10a). It appears essential to attain the sufficient leaf area and the increase in chlorophyll content for maximum yield. However, too much leaf area at the highest N level up to the ripening stage was not beneficial for dry matter production.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.242-253
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• 1984

Four different levels of nitrogen were applied to 3 naked barley cultivars (Hordeum vulgare L.) Yonezawa, Baekdong and Yeongsanbori. Changes in physico-chemical properties were examined upon these treatments. Total protein content as well as glutelin increased as N level increased. Baekdong contained the highest protein content (13.7%) at N$_2$. Yonezawa and Baekdong contained more lysine than Yeongsanbori. Increased lysine was measured in all cultivars by increased nitrogen application. Among all amino acids proline was the highest in all cultivars, and its increase was paralled to the N levels. Magnesium and potassium were declined and calcium was increased with increased levels of nitrogen fertilizer. Ash content was decreased as nitrogen increased and as the plants have become matured. Three minutes pearling in Yonezawa was not sufficient in terms of water absorption ratio and whiteness. Sixty percent pearling rate in Yonezawa showed a higher absorption ratio and cooking whiteness than non-waxy Baekdong and Yeongsanbori. Gelatinization temperature was lower but maximum viscosity was higher in waxy than non-waxy barley.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.249-267
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• 2016

The Hongseong area of the central-western Korean Peninsula is considered to be a part of collision zone that is tectonically correlated to the Qinling-Dabie-Sulu belt of China. The area includes the elliptical-shaped serpentinized ultramafic bodies, together with mafic rocks. The studied bodies are in contact with the surrounded Neoproterozoic alkali granites at the Baekdong and Wonnojeon bodies and the Paleoproterozoic Yugu gneiss at the Bibong body. The Baekdong body contains the blocks of the Neoproterozoic alkali granites and the Late Paleozoic metabasites. The Bibong body also includes the Neoproterozoic alkali granite blocks. The Mesozoic intrusive rocks are also recognized at the Baekdong, Wonnojeon and Bibong bodies. On the other hand, the Early Cretaceous volcanic rocks are occurred at the Bibong body. The detrital zircon SHRIMP U-Pb ages of the serpentinites at three bodies range variously from Neoarchean to Middle Paleozoic at the Baekdong body, and from Neoarchean to Early Cretaceous at the Wonnojeon and Bibong bodies. Although serpentinization does not generally produce minerals suitable for direct isotopic dating, the youngest Middle Paleozoic age at the Baekdong body and the Early Cretaceous age at the Wonnojeon and Bibong bodies indicate the possible upper age limit for the (re)serpentinization. Especially, the Early Cretaceous serpentinization ages may be related to the widespread Early Cretaceous igneous activity in the central-southern Korean Peninsula. Age results for the serpentinite bodies and the included blocks of the studied serpentinized ultramafic bodies in the Hongseong area, therefore, provide several possible interpretations for the serpentinization ages of the ultramafic rocks as well as the geotectonic implications of serpentinization, requiring more detailed study including other serpentinized ultramafic bodies in the Hongseong area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.123-129
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• 1982

To determine the optimum harvesting date with good grain yield and quality, six different harvesting dates were tested from 25 to 50 days heading with five days intervals, using two varieties of Baekdong, naked barley and Olmil, wheat. The dates when grain yield, 1,000 grain weight and grain/whole spike weight ratio were reached to the highest were 35 and 40 days after heading for Baekdong and Olmil, respectively. Various grain qualities such as unhulled grain, plumpness, protein content and whiteness of grain were also very good at that times. One day earlier harvesting before the optimum dates resulted in yield decreases by 3.9% for Baekdong and 4.4% for Olmil. And it might be delayed for each 5 days with Combine harvesting.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.1
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• pp.39-50
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• 2009

This study is for the occurrence types of asbestos within 2 serpentinite mines, Baekdong and Kwangsi, Chungnam. They were exploited as serpentinite mines for several decades and closed in the 1980's. Asbestos with associated minerals were collected from the serpentinite bodies. They were examined with microscopes and FESEM, and analysed with EPMA, XRD and EDX to confirm for the types and/or compositions of the minerals. The serpentinites contain asbestos and nonasbestos minerals. Asbestos include chrysotile, tremolite and actinolite. The chrysotiles occur as veins of several mm to cm thickness with random directions. The tremolite and actinolite occur along cracks and fractures of several cm to ten cm thickness. They show mineralogical characteristics showing common asbestos under the microscope. Non-asbestos including chrysotile, lizardite, antigorite, tremolite and actinolite were also found within the serpentinite. The serpentines form pseudomorphic mesh textures, and also show hourglass or ribbon textures. The tremolite and actinolite were formed from the alterations of the pyroxenes and amphiboles, and plot between tremolite and magnesio hornblende. Tremolitic grains are colorless and occur as commonly elongated grains whereas the magnesio hornblende grains mainly show light green and occur as subhedral to euhedral grains. Overall results suggest that three types of asbestos are found in the Baekdong and Kwangsi serpentinite mines with varieties of the occurrences. Based on the occurrence types for the asbestos, additional studies are required for the asbestos of the top soil and the air.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.152-156
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• 1984

Germination and emergence of 16 barley cultivars bred in Korea were studied under different low temperature conditions in laboratory at Suweon. This study revealed that the barley cultivars differed markedly in their germination rate index (GRI), emergence rate index (ERI), and dry matter weight. The seeds of Baekdong, Namhaebori, Gangbori and Buheung germinated better than others in $4^{\circ}C$ plot. Yeongsanbori, Kwangseong and Baekdong had very poor ERI values, but Buhobori, Namhaebori, Oweolbori, Albori and malting barley, Sacheon 6 had very good ERI values. Germination rate index were not correlated with emergence rate index under any temperature conditions. The correlation coefficient between ERI of $4^{\circ}C$ and $7^{\circ}C$ plots was very high. Those results showed that for screening the varieties or lines with good emergence capacity under low temperature conditions ERI, FS and dry matter weight would be available.

• Korean Journal of Environment and Ecology
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• v.12 no.3
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• pp.271-278
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• 1998

Heavy metal concentrations in rocks and soils from serpentinite(SP) and in plants (Pinus densiflora: PD and Pinus rigida: PR) were examined at Baekdong mine in Hongsung, Chungnam. Parent rocks were compared with amphibole schist(AS) and gneiss(GN) and plants divided the above grounds and roots were examined, respectively. In rocks, Ni, Cr, Co, Fe concentrations in SP were higher than those in AS and GN. The concentrations of top soils had the similar differences to their rocks; especially Ni, Cr, Co, Fe concentrations were the highest in SP, Zn and Sc concentrations, however, were the highest in AS. Average Ni, Cr, Co, Au, As, Sb, W concentrations of PD were the highest in SP and especially Ni, Cr, Co concentrations were accorded with changes of rocks and top soils. Zn and Sc concentrations in AS were higher and Fe and Mo concentrations in GN were higher than those in SP. Compared with two plants in the same serpentinite sites, most elements of PR were higher than those of PD. Therefore, these suggested PR absorbed much heavy metal than PD. Most element concentrations of roots in two plants and three rocks were higher than those of the above ground. Relative ratios (average plant concentration/soil concentration) of Ni, Cr, Co, Zn, Sc, Fe in AS and GN were higher than those of SP. Especially, relative ratios of most elements except Zn in GN were the highest.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.91-96
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• 1986

This study was carried out to clarify the barley grain development process under the double cropping paddy. The maximum length, width, and thickness of Baekdong were reached at 33,42, and 45 days after heading. They were not significantly reduced by 11, 7, and 5 days earlier harvesting than their above maximum develop-ing periods, respectively. Physiological maturity times were observed at about 40-46 days after heading, and the moisture contents were ranged 28-31 %. Practical maturity times were about 7 -8 days earlier than physiological ones. The beginning times of the sharp development phase of grain were delayed for two to ten days by delay of seeding times. However, the periods of the stationary and the lag development phases were about nine to ten days each and they were little changed by seeding times.