• Conservation Science in Museum
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• v.31
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• pp.21-37
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• 2024

This paper sought to garner an understanding of Daegaya glass culture by observing the micro-structure and analyzing the chemical composition of 43 glass beads excavated from the No.73 and 74 ancient tombs in Jisan-dong, Goryeong, which are estimated to have a central age of 5th century CE. The visible characteristics and micro-structure of these artifacts were observed with a optical microscope and an scanning electron microscope, while their chemical composition was analyzed with an energy-dispersing spectrometer attached to the scanning electron microscope. As a result, the glass beads of Jisan-dong, Goryeong were identified to have been formed using various methods such as drawing, casting, and folding techniques, with the majority molded by the drawing technique. In terms of chemical composition, 32.6% were in the potash glass group and 67.4% in the soda glass group, with the latter divided into various fluxes such as high alumina glass, netron glass, and plant ash glass. Compared to Baekje's cultural region in the same age, the composition of these ancient glass artifacts demonstrates a high share of the potash glass group. This shows that, despite the shift from the potash glass group to the soda glass group in ancient Korean glass culture, glass composition differs from region to region or depending on the cultural sphere of influence. In the soda glass group, high-alumina glass comprised 23.3%, natron glass 43.0%, and plant ash glass was 1.2%. Among them, the main type of Korean soda glass is high-alumina glass, as natron glass and plant ash glass are known to have appeared later, but the results of scientific analysis of the glass beads excavated in Jisan-dong can be expected to provide important clues about the inflow and transformation of ancient glass on the Korean Peninsula. In the No. 73, 74, and 74-1 ancient tombs, which were found to have been built in chronological order by the excavation survey, the glass beads showed only slight variations depending on their production period. Nonetheless, the chemical composition of glass is deemed to have a close correlation to color.

• Journal of Plant Biology
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• v.19 no.2
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• pp.37-40
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• 1976

The experiment designed to obtain information relative to the favourable levels to apply N.P.K fertilizer was conducted at the hop garden of College of Agriculture, S.N.U. in 1975. The varieties used were 1-year-old Cascade, Hallertau and Shinshuwase. The design of the experiment was a split plot design with 3 replications. Yields were recorded as fresh weight of harvested cones in gram per split plot. The results obtained from the experiment were as follows: 1. The results from analysis of the data for 3 varieties indicated that significant increase in yield were found due to the application of 46g N, 20g P2O5 and 60kg K2O per plant, although higher level thn the above caused a remarkable reduction of yield. 2. The individual fresh weight of harvested cones was significantly increased with application of nitrogen, phosphorus and potash, regardless of fertilizer levels. 3. Analysis of variance for yields showed that there were no significant interaction between fertilizer level and variety, i.e., all varieties used might require the same fertilizer level.

• Journal of the Korean Ceramic Society
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• v.11 no.3
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• pp.3-13
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• 1974

In order to clarify, factors affecting on mechanical strengthof porcelain bodies, some experiments were carried out for bobies consisting of Hadong kaolin, quartz of optical glass grade and potash-feldspar. At first, degree of vitrification of the fired bodies were examined from the results of bulk density measurement. Constituent minerals of these fired bodies were mainly examined by means of X-ray diffraction, and their microstructure were observed by means of the polarization microscope and scanning electron microscope. Transverse and impact strength of the bodies were also determined. Finally, relations between their mechanical strength and the other properties obtained were discussed. The mechanical strength, at least the transverse strength increased with increasing densification of the bodies and accompanied with an increase of stress produced in the quartz grains and, perhaps other phases composing the bodies.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.253-257
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• 1984

A field experiment was conducted in order to secure the basic information on the rational application of nitrogen and potassium for autumn growing Chinese cabbage (Brassica campastris ssp. pekinensis, var.; Miho 70 days). The results of the experiment are summarized as follows: 1. Potassium effect was observed where nitrogen applied either less than 15kg N/10a and heavy dose of 25kg N/10a. No potassium effect was observed where 20kg N/10a applied. In the case of 25kg N/10a, potassium effect was observed only in total weight but failed yield marketable product weighing over 1 kilogram per cabbage. 2. Nitrogen application, in general, tends to lower the soil pH and it is particularly true when heavy dose of over 20kg N/10a is applied. As a result, Chinese cabbage has increasingly removed soil born potassium and reduced exchangeable potassium content of the soil. 3. Oven dried cabbage which received 25kg N/10a plus potassium showed a low concentration of calcium and this phenomena seems to be attributable to the acidification of soils and it further caused failure in producing cabbages of marketing value.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.201-207
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• 1985

The experiments were conducted in order to evaluate the effect of a compound fertilizer for application of potato plants (Sumi) which were prepared by the Kyonggj Chemical LTD. The results were summarized as follows; 1. Comparing with the plot of 12kg/10a muriate of potash plot, the potato yield of compound fertilizer, double rate of potassium sulfate and normal rate of potassium sulfate plots were increased in order to 44%, 7% and 6% respectively. The yield of potato at the compound fertilizer were significantly higher than that of double rate of potassium sulfate, but the latter yield was lower that of control. 2. The yield of potato were to exeeding of final tuber on June 25, which was twelve day earlier than the actual harvest the application of the compound fertilizer may make possible to harvest potato eariler than normal season and benefit fammers which better economic return. 3. Manufacturing it with granular form at diammonium phosphate, ammonium sulfate and potassium sulfate as majour source materials and having little urea contents, the compound fertilizer raised higher the emergence rate of potato plant than the other fertilizer were promoted the early plant growth, and kept potato plants comparatively healthier than the other fertilizer even at later stage of plant growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.396-399
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• 1989

Pearl millet (Pennisetum americanum (L.) Leeke) is a promising forage crop that is resistant to biotic and abiotic stresses, and has a capability to grow well not only in the fertile soil, but also in the poor and dry soil, The objective of the study was to investigate the effects of increased fertilizer application level on the productivity and Quality of pearl millet in the old and newly reclaimed upland soils of Suwon, Chungju, Jeonju, Jinju and Jeju in Korea from 1986 to 1988, Plant height, green fodder yield, protein content and digestibility were increased by the increased fertilizer application level. However, the increased fertilizer application caused lodging, so that the plants grown above one meter in canopy height would be desiable to be clipped remaining 20cm above the ground surface before lodging, and fed to cattle, Mean green yields of the N 45-60kg/l0a application were 12.7-13.4t/l0a in the old upland soil. Increased phosphorus and potash fertilizer application also increased productivity, especially with potash fertilizer effect being higher than that of phosphorus fertilizer, In the newly reclaimed upland soil, improved and doubled fertilizer application plot of 60-60-40-4000kg/10a in N-P$_2$O$\sub$5/-K$_2$O-Compost was 38％ higher being 12.6t/10a of green fodder yield as compared with standard fertilizer application plot, Pearl millet productivity and Quality were higher than those of maize and sorghum/sudan grass hybrids, particularly in green fodder yield, protein content and digestibility.

• The Journal of the Petrological Society of Korea
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• v.12 no.4
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• pp.196-206
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• 2003

The geochemical and mineralogical investigation on the rocks and repair material comprising of the Sungryemun (The 1st National Treasure) has been made. Rock of the Sungryemun is highly weathered coarse-grained calc-alkali granite. The rock consists mainly of quartz, perthite, plagioclase and biotite with small amounts of orthoclase, muscovite, chlorite and sericite, which are major weathering products from perthite. For obtaining informations about degree of weathering, mineral composition of the original rock calculated by CIPW norm and weathered rock composition determined by XRD quantitative analysis were plotted on a ternary diagram of quartz-potash feldspar-plagioclase. Original rock compositions are plotted on the central granite area. whereas weathered ones are plotted on the granite area close to quartz. The result means that quartz is more abundant in weathered rock, due to selective chemical weathering of potash feldspar and plagioclase over quartz. On the whole, surface of the rocks were black-coated, exfoliated and highly fractured due to the physical and chemical weathering and heavy load has made the cracks in the lower parts of the stone construction. Also, cement and nails, which was used as repair material, during the repair work in the early 1960's, has accelerated the weathering process. Furthermore, weathered conditions of repair materials are very severe. Therefore, it is very urgent to establish of the conservation plan for the Sungryemun.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.188-193
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• 1982

Granulation formed from mixture of sulfate of potash (SOP) powder and pulverized silica minerals (Zeolite, Serpentine and Talc) was studied to establish granulation rate and physical properties of granules. These mixtures were granulated in a pan granulator with water and granules of SOP were coated with minerals powder. Mixture of SOP and mineral powder by half (w/w) were increased granulation rate compared with pure SOP powder, and talc was superior to them with SOP. Water was needed about 14% to granulate SOP powder alone, but it decreased by 2% with talc and increased by 4% and 2% with zeolite and serpentine, respectively. Granules of mixture of SOP with zeolite were harder than pure SOP granules but with another minerals powder decreased in hardness. Also breaking rate of granules in vinyl parcel falling from 2m height and abrasion rate of granules by agitation were improved by mixing and coating with zeolite but with the other were of inferior.

• Journal of Conservation Science
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• v.27 no.3
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• pp.323-332
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• 2011

Microtexture and components of 7 glass bead fragments excavated from Andong tumulus in Gildu-ri, Goheung have been analyzed to determine the characteristics of their weathered condition as well as chemical compositions. Firstly, status of microtexture shows that there is a large quantity of pollutants which were presumably transferred from the buried environment into the surface and the gap of the cracks. The examination has displayed that there are less amount of alkali metal components such as sodium (Na) and potasium (K) in the gap of the cracks than on the surface. The chemical compositions analysis has confirmed that two samples belongs to potash glass group ($K_2O-SiO_2$), four to soda glass group ($Na_2O-SiO_2$), and one to the mixed alkali glass group. Chromophoric elements of the glass varies by different colours: blue and navy are cobalt (Co); greenish blue is copper (Cu) and iron (Fe); and light brown is Fe respectively. Such kind of scientific analysis of the excavated glass beads will contribute to the understanding of interchange between various local cultures and arts within the southwest region of Korean Peninsula during the 4th and the 5th centuries.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.1-6
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• 2005

With recent interest organic farming the use of legumes including vetch and clover to provide N to adjacent crops is increasing in Korea. In the present studies, we conducted a trial to investigate the effects of the application of N rate on nitrogen fixation and transfer from vetch to barley in mixed stands. The experiment was arranged in a randomized complete block design with three replications. Four different N rates(0, 75, 113 and 150/ha) was used and vetch+barley was broadcasted manually on 1.5 $\times$2 m plot in Oct. 2001. Half of urea and K$_{2}O, 200 Phosphate and 75 kg potash per ha were applied as basal dressing md half of N md 75 potash were used for topdressing to soil surface on MarctL 2002. The equivalent of 1kg ha$^{-1}$ at($^{15}$NH$_{4}$)$_{2}$SO$_{4}$ solution at 99.8 atom $\%$$^{15}$N excess was applied to the microplot in mid April. Forage was harvested from each plot at ground level and separated into barley and vetch. Total N content and It values of samples were determined using a continuous flow stable isotope ratio mass spectrometry(IsoPrime-EA. Micromass, UK.). The percentage of legume H fixed from atmospheric N2 were 95.0, 93.8, 94.4 and $84.8\%$ with increment of N levels. The percentage of N transfer from vetch to barley by N-difference method with increment of N fertilizer were from 58 to$49\%$ while 39 to $23\%$ in $^{15}$N-dilution method. The amount of transfer from vetch to barley were 87 to 68 kg/ ha with N level by N-difference moth여 and 58 to -56/ha with N application levels by $^{15}$N dilution method. The amount of nitrogen fixation per ha were from 150 kg / ha to 219 kg / ha by different method, but on the other side 49 to 105kg/ha by N$^{15}$-dilution.