• Journal of Conservation Science
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• v.23
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• pp.103-118
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• 2008

Hobun(Oyster shell W.) is a traditional material used as extender and white pigment from ancient times. The production method of it, however, has been discontinued. We have studied the traditional production method of Hobun through calcination of oyster shell, which is one of the traditional ways for preparing Hobun. Our work has the important meaning in that we can reproduce the manufacturing method of the discontinued traditional material and also it provides a solid background knowledge to stabilize the production and supply of Hobun for the cultural asset repairing materials. The result can be summarized as followings: The production processes of Hobun by calcination method are divided into 4 steps - calcination ${\rightarrow}$ slaking(pulverization) ${\rightarrow}$ separating fine powder by submergence in water ${\rightarrow}$ drying. In calcination step, the temperature is required to exceed $700^{\circ}$ to get pure white color of Hobun, since organic materials in the shell cause the final powder to be less white below $600^{\circ}$. And the calcination methods produce significant amount of calcium hydroxide, which is incongruent for pigment materials without additional treatments. The experimental study also demonstrated that the additional treatment process introduced in traditional paintings can be a probable process since the calcium of potassium hydroxide is observed to be promoted by this treatment. It is also concluded that, the calcination method of Hobun is appropriate for a small amount and high quality production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.37-43
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• 2019

Since 3D printed concrete can be constructed without formwork, it is easy to construct an atypical structure, and the construction time and labor cost can be reduced. However, since the construction is exposed to the outside, shrinkage cracking due to moisture loss inside and outside the concrete occurs. Therefore, in order to improve the durability of the 3D printed concrete, a shrinkage reduction plan of the 3D printed concrete is required. In this study, glycol-based and alcohol-based shrinkage reducing agents were fabricated and evaluated for their performance. The shrinkage reducing agent samples showing excellent performance were selected and applied to 3D printed concrete. As a result, the compressive strength was increased by more than 10% and the shrinkage was reduced by more than 36% when using a shrinkage reducing agent. It is expected that the production of high quality 3D printed concrete will be possible because it is possible to increase the compressive strength and reduce the amount of dry shrinkage by applying a shrinkage reducing agent for 3D printed concrete.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.235-241
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• 2002

The detection of tubercle bacilli (TB) from sputum smear is one of the fast and inexpensive methods for diagnosis of tuberculosis. For this method. sputum smears are usually flexed by heating and stained by acid-fast staining method, and then examined under an optical microscope. Two Procedures are commonly used fur TB staining. One is hot staining and the other is cold staining method. The Ziehl-Neelsen method which is a hot staining method is widely used in Korea because its stained color is more vivid However, the conventional automated stainer has to fix the sputum smear on a slide manually and the stain is not so vivid because it has not heating function. In an effort to save labor and minimize variations in manual staining Procedure. we developed an automated stainer with heating function. The entire staining process is fully automated. from fixation to final washing and drying. With the automated methods, five slides can be flexed and stained in 21 minutes at consistent high quality We compared the concordance rate between the two methods for 91 sputum samples to validate the stain quality of the developed automated stainer. As the results, the concordant rate between the two methods was 95% and there was no significant difference (p>0.05)

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.3
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• pp.277-282
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• 2015

This study is conducted to utilize waste concrete powder (WCP) made as a by-product manufacturing high quality recycled aggregate. The blaine fineness of the used waste concrete powder was $928cm^2/g$. As the main characteristic of waste concrete powder, it showed an angular type similar to cement, but hydrated products were attached on the surface of particles. In addition, the size of the particles of waste concrete powder was larger than OPC and in terms of chemical components it had higher $SiO_2$ contents. For using WCP in soil cement-based pavement, the qualities, physical and chemical properties, of WCP should be researched. In the first step, the specified compressive strength of mortar for two types of clay sand soil and clay soil respectively was experimented to be 15 MPa and then optimum mixing ratio of chemical solidification agent were decided in the range of 1.5 - 3.0% in the replacement with cement weight content. In the second step, based on the prior experimental results, recycling possibility of WCP in soil cement-based pavement was studied. In the result of experiment the mixing ratio of WCP were 5, 10, 15 and 20% in the replacement with soil weight and the compressive strength of mortar was somewhat decreased according to the increase of the mixing ratio of WCP.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.362-372
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• 2000

This study was conducted to obtain the basic information on the production of high yield and qualitied yam in Andong, major yam-producing district, in Kyongbuk province, using three major Yam cultivars, such as Danma, Jangma and Alata (round type). Alata showed the longest tuber width while Jangma showed the longest tube length. Danma showed the highest tube yield at 2,123 kg/10a. Tubes of Alata had higher dry ratio than those of other cultivars, suggesting that Alata could be used as good processing materials. Characteristics of top parts, such as vine length, leaf number, and lateral vine number showed typical sigmoid curves. Tuber characteristics such as length, width and fresh weight of tuber were linearly increased as the growth period was progressed. Relative growth rate (RGR) for new tuber and stem reached the highest value at 86 DAT (days after transplanting). There were similar tendencies among the cultivars in net assimilation rate (NAR). The highest crop growth rate (CGR) was appeared at 156 DAT regardless of cultivars. In the changes of leaf area ratio (LAR), there were significant differences among three cultivars. LAR were decreased at 86, 106 and 136 DAT for Alata, Danma and Jangma, respectively. However, specific leaf weight (SLW) was greatly increased at 176 DAT, and leaf area index (LAI) was decreased at 156 DAT in all cultivars.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.20-31
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• 2024

Purpose: Research and development of high-strength concrete enables high-rise buildings and reduces the self-weight of the structure by reducing the cross-section, thereby reducing the thickness of beams and slabs to build more floors. A large effective space can be secured and the amount of reinforcement and concrete used to designate the base surface can be reduced. Method: In terms of field construction and quality, the effect of reducing the occurrence of drying shrinkage can be confirmed by studying the combination of low water bonding ratio and minimizing bleeding on the concrete surface. Result: The ease of site construction was confirmed due to the high self-charging property due to the increased fluidity by using high-performance water reducing agents, and the advantage of shortening the time to remove the formwork by expressing the early strength of concrete was confirmed. These experimental results show that the field application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher can be expanded in high-rise buildings. Through this study, we experimented and evaluated whether ultra-high-strength concrete with a strength of 130 MPa or higher, considering the applicability of high-rise buildings with more than 120 floors in Korea, could be applied in the field. Conclusion: This study found the optimal mixing ratio studied by various methods of indoor basic experiments to confirm the applicability of ultra-high strength, produced 130MPa ultra-high strength concrete at a ready-mixed concrete factory similar to the real size, and tested the applicability of concrete to the fluidity and strength expression and hydration heat.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.87-91
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• 1988

We studied the effects of the seed root weight and the local varieties on the yield and the quality of Cnidium officinale Makino root. The fresh and dried root weight per plant was found to be 92.7 g and 18.5 g in the large seed root(20-25 g), while 94.5 g and 17.0 g in the small seed root(15-20 g), respectively. The fresh and dried roots were produced 906.8kg/10a and 190.2kg/10a in the large seed root, but 721.2kg/10a and 165.2kg/10a in the small seed root, respectively. The root weight per plant, root yield per 10a and diethyl ether extract contents in root of Ul-Reung cultivar were higher than those of the other varieties. The root weight per plant and root yield per 10a were positively correlated with the contents of diethyl ether extracts in the large seed root, and with the ash contents of root in the small seed root. It is recommended for the high quality root production of cnidium officinale Makino to select and cultivate the large seed root(20-25 g) of Ul-Reung cultivar.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.94-101
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• 2018

Mugwort (Artemisia princeps) is a medicinal plant that has a substance called euphatilin, which is effective for cell damage and gastritis recovery. The objectives of this study were to investigate the annual growth characteristics of Artemisia princeps in greenhouse and to increase the eupatiline content by environmental stresses. Growth and eupatilin content of the plants were compared after 6 weeks of seedling and subsequent 8 weeks of greenhouse cultivation. Photosynthesis of mugwort plants did not saturate even at a relatively high light intensity of $1,200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Growth rate of the plants reached its highest at two weeks after transplanting and began to decrease since 8 weeks after transplanting. The plants showed typical characteristics of a perennial herbaceous plant as they were sensitive to seasonal changes. In particular, the plants showed high growth and eupatilin content in spring and summer as vegetative growth periods, but flowering and wintering caused considerable decreases in growth and eupatilin content in fall and winter. Therefore, application of night interruption is essential for year-round cultivationof the plant. Two stresses and a elicitor were treated: drought stresses by stopping irrigation at 5, 6, 7, and 8 days before harvest; salt stresses with nutrient solution concentrations of 2, 4, 6, 8, and $10dS{\cdot}m^{-1}$ by adding sodium chloride at 3 days before harvest; and foliar applications of methyl jasmonates of 12.5, 25, 50, and $100{\mu}M$ at 3 days before harvest. Significant increase in eupatilin content was observed at drought stresses of 7- and 8-days of irrigation stop and foliar application of $25{\mu}M$ methyl jasmonate, while no significant increase observed at salt stresses. From the results, it was confirmed that the environmental treatments can improve the productivity and quality of Artemisia princeps as a phamaceutical raw material.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.414-421
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• 2019

Pod shattering during the maturing stage causes a serious yield loss in soybean. It is the main limiting factor of soybean cultivation and mechanization. It is important to develop varieties suitable for mechanical harvesting and to develop energy-efficient agricultural machinery to save labor and costs. 'Daewonkong,' developed by the National Institute of Crop Science (NICS) in 1997, is an elite cultivar that occupies more than 80% of the soybean cultivation area in Korea because of its strong tolerance to pod shattering. The objectives of this study were to investigate the variation in pod shattering degree in a RIL population developed from a 'Daewonkong' parent and to select promising lines with pod shattering tolerance. 'Daewonkong' demonstrated a high level of tolerance to pod shattering compared to the 'Tawonkong' and 'Saeolkong' varieties, with no shattered pods after 72 hours of drying. Screening of pod shattering showed a clear distinction between the tolerant and susceptible varieties. Also, the distribution of shattering pod ratio in the two populations showed a similar pattern for three years. The promising lines with pod shattering tolerance included 27 lines in the 'Daewonkong'×'Tawonkong' population and 21 lines in the 'Daewonkong'×'Saeolkong' population. The promising lines are expected to be widely used as breeding parents for creating soybean cultivars with pod shattering tolerance.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.66.1-66.1
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• 2011

반도체를 비롯하여 LCD, OLED와 같은 디스플레이 (FPD: Flat Panel Display) 분야는 국가 선도 사업으로써 발전을 거듭해오고 있다. 하지만 기술의 성숙도가 높아짐에 따라 최근 중국과 대만 업체와의 경쟁이 심화되고 있으며, 더불어 환경문제가 큰 이슈로 떠오르고 있어 신기술 개발을 통한 생산 수율 향상 및 친환경 공정 개발의 중요성이 커지고 있다. 반도체, 디스플레이 공정에서 생산 수율 저하의 주요 원인으로써 공정 중 발생하는 미세 오염 입자를 들수 있다. 반도체 및 디스플레이 공정에서 세정 기술은 전체 기술의 30% 이상을 차지하며 생산 수율 및 제품의 품질에도 큰 영향을 주는 공정이다. 세정 공정은 일반적으로 습식 세정 공정이 낮은 공정비용을 바탕으로 널리 적용되어 왔으나, 기판의 대형화와 패턴의 미세화에 따라 정밀한 세정 스펙이 요구되며 더불어 막대한 양의 초순수와 화학액의 사용으로 인한 공정비용 증가와 환경 규제 강화에 따른 폐수 처리의 문제에 직면하고 있다. 이에 따라 폐수의 양을 줄이며 건조공정을 필요로 하지 않아 공정비용을 줄일 수 있는 건식 세정 공정에 대한 연구가 활발히 진행 되고 있다. $CO_2$ snow jet 세정 기술은 건식 공정으로써 $CO_2$ 가스를 특수하게 제작된 분사 노즐에서 고압으로 가스를 분사하여 이 때 발생되는 순간적인 감압에 의한 단열 팽창으로 생성된 $CO_2$ snow 입자가 기판 표면의 오염물과 물리적 충돌을 하어 세정이 이루어지는 기술이다. 특히 $CO_2$ 세정은 환경과 인체에 무해하며 공정 후 바로 승화하기 때문에 추가적인 폐수처리 공정 등이 필요하지 않고, 건식 공정으로써 수세(Rinse) 공정을 필요로 하지 않기 때문에, 공정비용을 크게 줄일 수 있으며 물반점 발생을 방지 할 수 있는 친환경 건식 공정으로써의 장점을 가지고 있다. 본 연구에서는 자체적으로 개발한 $CO_2$ snow jet을 바탕으로 하여 다양한 공정조건을 변화시켜 세정효율을 측정하는 한편, 최적화 하기 위한 연구를 진행하였으며 더불어 $CO_2$ snow의 세정력을 정량적으로 평가하기 위한 연구를 진행하였다. 실험을 통해 가장 효과적으로 $CO_2$ snow 입자를 배출 할 수 있는 공정 조건으로써 5 bar의 캐리어 가스 압력을 사용하여, 세정력에 가장 큰 영향을 줄 수 있는 분사 노즐과 기판 사이의 거리 및 분사 노즐의 각도 등을 변화시켜 각 조건에 따른 세정효율을 평가하였다. 세정 오염물은 Silica, PSL 표준 입자(Duke scientific, USA)를 정량적으로 웨이퍼에 오염 시킨 후, 파티클 스캐너(Surfscan 6500, KLA-Tencor, USA)를 이용하여 세정 전 후의 오염입자 개수 변화를 통해 정량적으로 세정효율을 평가하였다. 본 연구를 통하여 $CO_2$ snow jet를 이용한 친환경 고효율 건식 세정 공정 메커니즘을 분석하였으며, 노즐과 기판 사이의 간격 및 분사 노즐의 각도 등을 최적화 한 세정 공정을 얻을 수 있었다.