• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.141-155
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• 2023

Monitoring technology based on electrical resistivity is widely used for non-destructive data collection and health analysis of underground structures and tunnels. Vulnerable sections such as fault zone generates many problems during construction of the tunnel. These problems cause displacement and stress changes of the ground. Therefore, it is necessary to predict the state of the fault zone section to ensure the mechanical stability of the underground structure. Monitoring the size of joints and the porosity of the fillings is essential for rocks. Previous studies have not considered the variety of fillings in rock joints. In this study, electrical resistivity tests were conducted according to the particle mixing state of the sandy fillings. When the size of fillings is decreased at the constant porosity, the electrical resistivity tends to increase. The results of this study are expected to be useful as basic electrical resistivity data for predicting the ground conditions and evaluation of the ground behavior that is containing sandy fillings in the rock joint for tunnels.

• Journal of the Korean Orthopaedic Association
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• v.54 no.1
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• pp.24-29
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• 2019

Purpose: To evaluate the characteristics and the risk factors of early onset subsequent vertebral compression fractures after percutaneous vertebroplasty. Materials and Methods: A total of 44 patients, who had a new subsequent vertebral fracture after percutaneous vertebroplasty for an osteoporotic vertebral compression fracture between January 2013 and December 2015, were recruited. The patients were divided into two groups according to the onset period of subsequent fracture. The number of patients who had a fracture within 3 months following vertebroplasty were 22 cases (Group A); after 3 months were 22 cases (Group B). Variables, including age, sex, bone mineral density (BMD), body mass index (BMI), preexisting vertebral compression fracture, location of the initial fracture, intradiscal cement leakage, injected cement volume, restoration of vertebral body height, and correction of kyphosis, in the two groups were analyzed and compared retrospectively. Results: The age, sex, BMD, BMI, preexisting vertebral compression fracture, location of the initial fracture, intradiscal cement leakage, and correction of kyphosis were similar in the two groups. Both a greater volume of bone cement injected and a greater degree of vertebral height restoration contributed significantly to the risk of fracture within 3 months. Conclusion: The cement volume and degree of height restoration are risk factors for early onset fracture at the adjacent vertebrae after percutaneous vertebroplasty and close attention is needed during the follow-up period.

• Resources Recycling
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• v.32 no.3
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• pp.18-25
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• 2023

Sericite was ground with or without additives (LiNO₃ or TiO₂) using a planetary mill. The resultant ground products included the average particle size of 2-3 ㎛ (sericite only or sericite+LiNO₃) and 0.5-0.6 ㎛ (sericite+TiO₂) were obtained within 10 minutes of grinding time. respectively. In the grinding of the sericite without any addictive, the particle size initially decreased, but, as grinding time elapsed thereafter, agglomerates were formed and D50 increased over 10 ㎛. In contrast, when the additive was added, the particle size decreased as the grinding time elapsed and any aggregation was relatively not noticeable, compared with the grinding of the sericite only. As a result of measuring the zeta potential for the raw or the ground samples, variation of the zeta potential values according to pH at the early stage of the grinding with the addictives was gentler than that at the final stage of grinding, which showed the relatively similar trend to the pH-zeta potential correlation in grinding of raw sericite. In addition, as a result of the disintegration experiment through ultrasonic excitation, D50 decreased rapidly only until the disintegration time of about 50 minutes.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.619-628
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• 2023

In this study, we investigated the feasibility of calcium sulfate fertilizer as a stabilizing agent for As and Hg contaminated farmland soil and its stabilization characteristics in 3 different physical forms (particulate, powder, and solution) through a pot experiment including 34 days of lettuce growth. As and Hg contents of the lettuce grown in the stabilized soils were decreased by at least 70%. However the lettuce yield of the soil stabilized with the solution agent was decreased by 46% due to the overabundance of the nutrients from the solution agent. Thus, if a solution-type agent is planned for agricultural farmland soil stabilization, additional tests for optimal dosage are needed to preserve vegetation growth. In Hg fractionation, a lower concentration of elemental fractions and a higher concentration of residual/sulfide fractions were identified in the soils stabilized with the solution, powder, and pariculate agents in descending order while there were no significant changes in As fractionation. Overall results suggest that calcium sulfate fertilizer can be used as a stabilizing agent, and a solution-type agent could be used when the operation of heavy machinery for the soil stabilization process is impossible.

• Animal Bioscience
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• v.36 no.11
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• pp.1709-1717
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• 2023

Objective: A pivotal study was designed to investigate the effect of Hydroxy (HYC) Cu, Zn, and Mn on egg quality and laying performance of chickens under tropical conditions. Methods: A total of 1,260 Babcock White laying hens (20-wk-old) were randomly assigned to one of 4 treatments with 15 replicates of 21 hens each in a Randomized Complete Block Design. The birds were reared for 16 weeks and were fed the corn-soybean meal diets supplemented with one of the following mineral treatments: T1, inorganic (INO, 15 ppm CuSO4, 80ppm MnSO4 and 80 ppm ZnO); T2, Hydroxy-nutritional level (HYC-Nut, 15 ppm Cu, 80 ppm Mn, 80 ppm Zn from Hydroxy); T3, Hydroxy-Low (HYC-Low, 15 ppm Cu, 60 ppm Mn, 60 ppm Zn from Hydroxy); T4, Hydroxy plus inorganic (HYC+INO, 7.5 ppm HYC Cu+7.5 ppm CuSO4, 40 ppm HYC ZnO+40 ppm ZnSO4, 40 ppm HYC Mn+40 ppm MnSO4). The egg production was recorded daily, while the feed consumption, feed conversion ratio (FCR) and egg mass were determined at the end of each laying period. The egg quality parameters were assayed in eggs collected over 48 h in each laying period. Results: Overall, no significant effect of treatments was observed on percent egg production, egg weight and FCR (p>0.05). Feed intake was significantly lower in birds fed Hydroxy plus inorganic (p<0.05) diet. The supplementation of HYC-Low significantly increased the egg mass compared to the other treatments (p<0.05). HYC supplementation alone or in combination with INO elicited a positive effect on shell thickness, shell weight, shell weight per unit surface area, yolk colour, albumen and yolk index for a certain period (p<0.05), but not throughout the whole laying period. Conclusion: Dietary supplementation of HYC-Low (15-60-60 mg/kg) showed similar effects on production performance and egg quality characteristics in laying hens as compared to 15-80-80 mg/kg of Cu-Zn-Mn from inorganic sources. This indicates that sulphate based inorganic trace minerals can effectively be substituted by lower concentration of hydroxyl minerals.

• The Korean Journal of Food And Nutrition
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• v.36 no.5
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• pp.415-424
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• 2023

This study investigated the nutritional characteristics of before and after fermentation of domestic soybean (Glycine max L.) by Rhizopus oligosporus. The soybean storage proteins, β-conglycinin (11S globulin) and glycinin (7S globulin), were the most abundant in Seonyu (SY) and Danbaegkong (DBK), with concentrations of 253.4 mg/g and 193.0 mg/g, respectively. For 11S/7S related to sulfur-containing amino acid, DBK had a value of 0.95, making it the most excellent nutritionally among all the cultivars. The free amino acid content significantly increased from 0.04~10.45 mg/g before fermentation to 1.37~16.95 mg/g after fermentation, and the essential amino acid composition increased, confirming an improvement in protein quality after fermentation. Phytic acid, known as a nutritional inhibitor of soybeans, decreased from 1.66~2.13 g/100 g before fermentation to 0.90~1.58 g/100 g after fermentation, suggesting that mineral absorption inhibition was alleviated. In addition, the trypsin inhibitor content is suppressed by 76.20% to 81.25% after fermentation, which is expected to improve protein utilization in the body. This study confirmed some properties of fermented products by Rhizopus oligosporus using domestic soybeans, and these results are presented to serve as the basic data for establishing new uses of Korean soybean cultivars.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.160-189
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• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.196-212
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• 2023

This study identifies the origin of stone remains (pavement and banister stones) excavated from the first burial site of King Jeongjo through petro-mineralogical analysis in a quarry and examines the relationship with the stone remains from Geolleung (King Jeongjo's Tomb). The excavated stones from the first burial site of King Jeongjo are all light gray fine-grained biotite granite, and mainly contain quartz, feldspar, and biotite. The magnetic susceptibility of the stones ranges from 5.55 to 12.10 (average 7.00) (SI unit). According to old documents, the quarrying sites of the stones were Mts. Aengbong and Yeogisan (Godeung-dong District, Suwon), and we found a fine-grained biotite granite outcrop behind Mr. Aengbong (currently the site of Yeonggwang Apartment) with a geological survey, and it was petrologically similar to the stone remains from the first burial site. The magnetic susceptibility of the outcrop rocks was 5.15 to 7.24 (SI unit), and their petro-mineral and geochemical characteristics were found to be the same as those of the first buried site and Geolleung Tomb. It was confirmed that most of the stone elements in the first burial site were reused to build Geolleung Tomb while moving the grave. Only the pavement and banister stones seem to have been discarded in the first grave site without being transferred. This is because the size of the new burial mound became larger than the first grave during construction because Queen Hyoui (the consort of King Jeongjo) died and was buried together with the king in the same tomb, and the stone blocks did not fit a grave that size. With these research results, it was possible to compare and examine the old records and scientific analysis data, and they are expected to be used as basic source material in related research.

• Conservation Science in Museum
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• v.30
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• pp.89-100
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• 2023

Museum collections are comprised of a variety of materials, and different scientific examinations are being conducted according to the types and production properties of the materials, but insufficient research has been carried out on ultra-small artifacts. To identify the material characteristics of the white ultra-small materials excavated from Geumnyeongchong tomb, this study carried out a wide range of non-destructive analyses (specific gravity, microscopy, nano-computed tomography (Nano-CT), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Raman spectroscopy) and compared the said artifacts with the Goryeo-era burial accessories examined in prior research. Non-destructive analysis confirmed the presence of aragonite, which mainly consists of calcium carbonate (CaCO₃) as the constituent mineral, and identified the material used for the ornaments as the gemstone pearl based on its growth lines. This study concludes that pearls began to be used in the ancient Korean Peninsula in the 6^th century. It is expected that scientific examinations of the white ultra-small artifacts will yield information about the social culture of the time.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.363-379
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• 2014

The Haenam Pb-Zn skarn deposit is located at the Hwawon peninsula in the southwestern part of the Ogcheon Metamorphic Belt. The deposit is developed along the contact between limestone of the Ogcheon group and Cretaceous quartz porphyry. Petrography of ore samples, chemical composition of skarn and ore minerals, and geochemistry of the related igneous rocks were investigated to understand the characteristics of the skarn mineralization. Skarn zonation consists of garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone, pyroxene+garnet+quartz${\pm}$calcite zone, calcite+pyroxene${\pm}$garnet zone, quartz+calcite${\pm}$pyroxene zone, and calcite${\pm}$chlorite zone in succession toward carbonate rock. Garnet commonly shows zonal texture comprised of andradite and grossular. Pyroxene varies from Mn-hedenbergite to diopside as away from the intrusive rock. Chalcopyrite occurs as major ore mineral near the intrusive rock, and sphalerite and galena tend to increase as going away. Electron probe microanalyses revealed that FeS contents of sphalerite become decreased from 5.17 mole % for garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone to 2.93 mole %, and to 0.40 mole % for calcite+pyroxene${\pm}$garnet zone, gradually. Ag and Bi contents also decreased from 0.72 wt.% and 1.62 wt.% to <0.01 wt.% and 0.11 wt.%, respectively. Thus, the Haenam deposit shows systematic variation of species and chemical compositions of ore minerals with skarn zoned texture. The related intrusive rock, quartz porphyry, expresses more differentiated characteristics than Zn-skarn deposit of Meinert(1995), and has relatively high$SiO_2$ concentration of 72.76~75.38 wt.% and shows geochemical features classified as calc-alkaline, peraluminous igneous rock and volcanic arc tectonic setting.