• Resources Recycling
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• v.15 no.6 s.74
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• pp.48-55
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• 2006

This study was carried out for establishing the physical recycling technique for commercializing process on household batteries. The procedure involves shape separator, crushing, magnetic separation, classification and eddy current separation in sequence. The separation capacity was 400-600 unit cell/hr with shape separation system. The impurities such as manganese and zinc in the magnetic product were below 0.1% respectively, the concentration of iron was above 99% in spent carbon zinc battery. Also non-magnetic products are composed of 22-30% En, 16-22% Mn, 1-3% Fe in the case oi spent zinc carbon battery. The amounts of other components such as carbon rod, plastics and separator were about 37-50%. From the eddy current separation of nonferrous products, the plate-type zinc components were separated up to 96% with 2,250-2,750 meter/min of the conveyor speed.

• KSBB Journal
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• v.11 no.6
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• pp.718-725
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• 1996

Old newsprint was deinked with endoglucanase, exoglucanase and their various compositions from Trichoderma viride. The yield decreased with an increase in enzyme concentration. Especially, it was the lowest in the treatment of endo-exo mixture(1:1). It may be regarded as a synergistic actions of the cellulase components. The brightness was the highest in pulp deinked with endo-exo mixture(1:1). Maximum brightness was observed when 0.5mg/mL of the endo-exo mixture was used. The physical strength increased with increasing concentration in exoglucanase. But, it decrease with increasing concentration in endoglucanse and endo-exo mixture(1:1). Also, we investigated the yield, brightness and physical strength of endoglucanase in combination with exoclucanase(12:1, 8:1, 4:l, 1:1, 1:4, 1:8, 1:12). Maximal deinking conditions, obtained at a specific optimal ratio of endoglucanase to exoglucanse are as follow ; 12:1 for yield, 12:1 for brightness, 4:1 for tensile strength, 12:1 for bursting strength, and 8:1 for tearing strength. These results indicated that the deinking depended largely upon the action of endoglucanase. Exoglucanase was occupying more than 60% of the total crude cellulase contents. Therefore, the most effective deinking must repress the action of exoglucanase.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.87-91
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• 2017

Carbon-encapsulated Ni and metal Ni nanoparticles were synthesized by levitational gas condensation (LGC). Methane ($CH_4$) gas was used to coat the surface of the Ni nanoparticles. The Ni particles had a core diameter of 10 nm, and were covered by 2~3 nm thin carbon layers with multi-shells structure.The low magnetization comparing with the Ni nanoparticles without carbon-shell results in the coexistence of nonmagnetic carbon and a large surface spin percentage with disordered magnetization orientation for the nanoparticles. Biginelli reactions in the presence of L-proline and Ni and carbon encapsulated Ni nanoparticles were carried out to change the ratio between stereoisomers. The obtained S-enantiomers for 3,4-dihydropyrimidine (DHPM) using catalysts of Ni, and Ni@C was an excess of about ${\Delta}{\sim}7.4%$ and ${\Delta}{\sim}19.6%$, respectively. The nanopowders were fully recovered using magnet to reuse as a catalyst. The Ni@C was shown at same yield to formation of 3,4-DHPM, though it was recycled for catalyst in the reaction.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.1
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• pp.80-90
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• 2001

The aim of this study is to develop the methodology which enables to identify the mechanical properties of element such as stress intensity factor by using the AE parameters. Considering the multivariate and nonlinear properties of AE parameters such as ringdown count, rise time, energy, event duration and peak amplitude from fatigue cracks of machine element the principal component regression(PCR) and artificial neural network(ANN) models for the estimation of stress intensity factor were developed and validated. The AE parameters were found to be very significant to estimate the stress intensity factor. Since the statistical values including correlation coefficients, standard mr of calibration, standard error of prediction and bias were stable, the PCR and ANN models for stress intensity factor were very robust. The performance of ANN model for unknown data of stress intensity factor was better than that of PCR model.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.136-143
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• 2018

Cellular automata have been applied to simulations in many fields such as astrophysics, social phenomena, fire spread, and evacuation. Using cellular automata, this study develops a model for consequence analysis of the dispersion of hazardous chemicals, which is required for risk assessments of and emergency responses for frequent chemical accidents. Unlike in cases of detailed plant safety design, real-time accident responses require fast and iterative calculations to reduce the uncertainty of the distribution of damage within the affected area. EPA ALOHA and KORA of National Institute of Chemical Safety have been popular choices for these analyses. However, this study proposes an initiative to supplement the model and code continuously and is different in its development of free software, specialized for small and medium enterprises. Compared to the full-scale computational fluid dynamics (CFD), which requires large amounts of computation time, the relative accuracy loss is compromised, and the convenience of the general user is improved. Using Python open-source libraries as well as meteorological information linkage, it is made possible to expand and update the functions continuously. Users can easily obtain the results by simply inputting the layout of the plant and the materials used. Accuracy is verified against full-scale CFD simulations, and it will be distributed as open source software, supporting GPU-accelerated computing for fast computation.

• Korean Journal of Heritage: History & Science
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• v.50 no.4
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• pp.38-63
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• 2017

This study sets out to investigate the installation of royal kilns and its impact on local kilns, taking note of celadon vase with inlaid cloud pattern in Joseon Dynasty. For that purpose, it determined the kilns and period to produce celadon vases with inlaid cloud pattern, and compared them with the pattern, design, and deformity of the celadon vases produced in the royal kilns in the 15th centuries. The celadon vase with inlaid cloud pattern was superior in quality than the porcelain for tribute ware manufactured together in Jeolla Province before the installation of royal kilns. And then a majority of sagijangs at local kiln had difficult time securing enough supply of manpower and resources, and discontinued manufacturing the celadon vase with inlaid cloud pattern. En revanche, celadon vases with inlaid cloud pattern produced from specially fixed royal kilns reflected the local sagijang's skill. Local kilns were strongly influenced by the installation of royal kilns. Those could not freely use high-quality white clay, limited to the market. Besides, most of the skillful sagijangs were assigned to royal kilns. Celadon vases with inlaid cloud pattern can be used as evidence to show that the manufacturing technique was transferred from local kilns to the royal kilns as well as to show that their production in royal kilns soon became stabilized.

• Tunnel and Underground Space
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• v.31 no.4
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• pp.243-269
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• 2021

Since the early 2010s, the social importance of research and practical projects targeting deep geological disposal of high-level nuclear waste, underground CO₂ storage and characterization of deep subsurface by borehole investigation has been increasing. In this regard, there is also a significant increase in the need for in situ test technology to obtain quantitative and reliable information on the hydraulic characteristics of deep rock mass. Through years of research and development, we have independently set up Deep borehole Hydraulic Test System (DHTS) based on the key apparatuses designed and made with our own technology. Using this system, high precision constant pressure injection tests were successfully completed at the two 1 km boreholes located in Mesozoic granite and sedimentary rock regions, Gyeongju. During the field tests, it was possible to measure very low flow rate below 0.01 l/min with micro flow rate injection/control module. In this paper, the major characteristics of DHTS are introduced and also some results obtained from the high precision field tests under the deep and low permeable rock mass environment are briefly discussed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.36-36
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• 2019

정향풀[Amsonia ellipotica (Thumb.) Roem. & Schult.]은 5월에 백색의 취산꽃차례로 개화하여 관상가치가 높다고 판단되나, 전국에 자생지가 10곳 미만이며 한국적색목록에 위기종(EN)으로 평가되어 체계적인 번식 및 재배법 개발이 요구된다. 본 연구는 유전자원보전 및 신 관상소재로 개발 가능한 정향풀의 효과적인 육묘법을 확립하고자 수행되었다. 실험재료는 유용식물증식센터에서 분양받은 종자를 사용하였으며, 파종용기(72, 105 및 128구 트레이), 파종립수(셀 당 1, 2 및 4립), 토양종류(원예상토 단용 및 중화 피트모스와 펄라이트를 3:1 또는 4:1로 혼용), Hyponex[미분(6.5-6-19)] 추비농도(0, 250, 500 및 $1000mg{\cdot}L^{-1}$) 및 차광정도(0, 55 및 75%)를 달리하여 2019년 4월 20일부터 8주 동안 육묘하였다. 연구의 공통사항으로 종자를 $500mg{\cdot}L^{-1}$ $GA_3$에24시간 침지한 다음 원예상토를 충진한 105구 트레이에 셀 당 1립씩 파종하였으며, 이후 2, 4주차에 $500mg{\cdot}L^{-1}$ Hyponex를 엽면시비하였다. 연구의 결과, 파종용기는 셀 당 용적량이 많을수록 초장, 경직경, 엽수, 지상부 및 지하부 생체중이 증가하는 경향이었다. 파종립수에 따른 생육은 1립 파종 시 가장 우수하였으나, 2립 파종한 묘의 개체 당 생체중이 비교적 양호함에 따라 트레이 상 풍성한 볼륨감을 나타내었다. 추비처리의 농도가 증가할수록 유묘의 생육이 증가하는 경향이었으며, $1000mg{\cdot}L^{-1}$ 처리구에서 초장, 경직경, 엽수 및 생체중이 유의적으로 높았다. 한편 차광처리 시 차광정도에 관계없이 경직경, 엽수, 마디수 및 지상부 생체중이 유의적으로 감소하였다. 따라서 정향풀은 용적량이 큰 72구 트레이에 원예상토를 충진한 다음 셀 당 2립씩 파종하여 차광하지 않은 양지에서 Hyponex $1000mg{\cdot}L^{-1}$로 추비하는 것이 관상목적으로 육묘하기 위한 효과적인 재배법으로 판단된다.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.184-192
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• 2022

Porous NiO synthesized via hydrothermal synthesis was used in the electrodes of lithium-sulfur batteries to inhibit the elution of lithium polysulfide. The electrode of the lithium-sulfur battery was manufactured as a freestanding flexible electrode using an economical and simple vacuum filtration method without a current collector and a binder. The porous NiO-added S/CNT/NiO electrode exhibited a high initial discharge capacity of 877 mA h g^-1 (0.2 C), which was 125 mA h g^-1 higher than that of S/CNT, and also showed excellent retention of 84% (S/CNT: 66%). This is the result of suppressing the dissolution of lithium polysulfide into the electrolyte by the strong chemical bond between NiO and lithium polysulfide during the charging and discharging process. In addition, for the flexibility test of the S/CNT/NiO electrode, the 1.6 × 4 cm² pouch cell was prepared and exhibited stable cycle characteristics of 620 mA h g^-1 in both the unfolded and folded state.

• Journal of Life Science
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• v.32 no.10
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• pp.762-770
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• 2022

Hyperglycemia in type 2 diabetes can be alleviated by promoting cellular glucose uptake. Betulinic acid (3β,-3-hydroxy-lup-20(29)-en-28-oic acid) is a pentacyclic lupane-type triterpenoid compound. Although there have been studies on the antidiabetic activity of betulinic acid, studies on cellular glucose uptake are lacking. We investigated the effects of betulinic acid on glucose uptake and its mechanism of action in 3T3-L1 adipocytes. Betulinic acid significantly stimulated glucose uptake in 3T3-L1 adipocytes by increasing the phosphorylation of the insulin receptor substrate 1-tyrosine (IRS-1tyr) in the insulin signaling pathway, which in turn stimulated the activation of phosphoinositide 3-kinase (PI3K) and the phosphorylation of protein kinase B (Akt). The activation of PI3K and Akt by betulinic acid translocated glucose transporter 4 to the plasma membrane (PM-GLUT4), thereby increasing the expression of PM-GLUT4 and thus stimulating cellular glucose uptake. Betulinic acid also significantly increased the phosphorylation/activation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. The activation of PI3K and AMPK by betulinic acid was confirmed using the PI3K inhibitor wortmannin and the AMPK inhibitor compound C. The increase in glucose uptake induced by betulinic acid was significantly decreased by wortmannin and compound C in the 3T3-L1 adipocytes. These results suggest that betulinic acid stimulates glucose uptake by activating PI3K and AMPK in 3T3-L1 adipocytes.