• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.469-473
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• 2017

In this study, the rheological characteristics of kerosene based gel propellants were investigated. For the gelling agent, Thixatrol$^{(R)}$ has been used with 100 nm nano-sized aluminium particle addition. Three gellant contents of 2.5 wt%, 5 wt% and 7.5 wt% kerosene gels were first investigated where aluminium particles contents of 10 wt% and 20 wt% were added to 7.5 wt% gellant case. The viscosities of each sample measured by rotational rheometer show that the viscosity augments as gellant or aluminium content increases while the 20 wt% aluminum content resulted in failure of measurement due to the agglomerations of aluminum particles.

• Journal of Ginseng Research
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• v.45 no.3
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• pp.442-449
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• 2021

Background: Panax ginseng is an important crop in Asian countries given its pharmaceutical uses. It is usually harvested after 4-6 years of cultivation. However, various abiotic stresses have led to its quality reduction. One of the stress causes is high content of heavy metal in ginseng cultivation area. Plant growth-promoting rhizobacteria (PGPR) can play a role in healthy growth of plants. It has been considered as a new trend for supporting the growth of many crops in heavy metal occupied areas, such as Aluminum (Al). Methods: In vitro screening of the plant growth promoting activities of five tested strains were detected. Surface-disinfected 2-year-old ginseng seedlings were dipping in Rhizobium panacihumi DCY116^T suspensions for 15 min and cultured in pots for investigating Al resistance of P. ginseng. The harvesting was carried out 10 days after Al treatment. We then examined H₂O₂, proline, total soluble sugar, and total phenolic contents. We also checked the expressions of related genes (PgCAT, PgAPX, and PgP5CS) of reactive oxygen species scavenging response and pyrroline-5-carboxylate synthetase by reverse transcription polymerase chain reaction (RT-PCR) method. Results: Among five tested strains isolated from ginseng-cultivated soil, R. panacihumi DCY116^T was chosen as the potential PGPR candidate for further study. Ginseng seedlings treated with R. panacihumi DCY116^T produced higher biomass, proline, total phenolic, total soluble sugar contents, and related gene expressions but decreased H₂O₂ level than nonbacterized Al-stressed seedlings. Conclusion: R. panacihumi DCY116^T can be used as potential PGPR and "plant strengthener" for future cultivation of ginseng or other crops/plants that are grown in regions with heavy metal exposure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.4-4
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• 2009

Surface analysis on defective wire-bonding pads are performed in flash memory assembly. Week wire bonding may cause a significant effect on the final product reliability, and the surface condition of the aluminum bond pads is critical in terms of product reliability. To find out possible week bonding on semiconductor interconnects, ball sheer test (BST) has been performed. On some defective or week bonded pads, we have investigated the surface contents, assuming that the week bonding is induced from the surface conditions. AES and XPS are employed for the quantitative surface analysis on defective dies.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.113-118
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• 2006

In this work, we observed the changes in mass difference according to Al-foam's amount of Ca contents which depends on the viscosity control of fusion, quality of foamed addition, mixing, temperature tests. These are crucial influencing factors in determining foam-metal's size in the manufacturing process. In order to obtain the specimen, we changed the specific gravity from 0.2 to 0.3 for the study of the light weight, and obtained the optimal values of specific gravity, and then showed the mechanical characteristics of ultra-lightweight metal according to the changing mass. The optimal conditions for aluminum foam is when the addition of Ca content in $1.5wt\%~2.0wt\%$

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.389-391
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• 1995

Using as an alternate of insulating material for outdoor and cable, however, it has still many problems to be solved in the field of material such as resistances of environment and tracking. In this paper, Tracking property of PVC filled with aluminum hydroxide have been investigated by ASTM D 2303 method. It was found that time to track of PVC filled aluminum hydroxide was longer than that of unfilled PVC. Tensile strength and elongation of PVC were decreases increased with aluminum hydroxide contents. On the other hand, Thermegravimetry of PVC decreased. Therefore, the increase of time to tracking breakdown by antitracking additive can be explained by increased degradation temperature of polymer.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.1
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• pp.47-58
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• 2004

Loss factors of A356, Mn-Cu alloy and aluminum matrix composites reinforced with $SiC_p$ and Ni-coated graphite particles at various contents have been investigated using clamped-free cantilever beam method. The loss factors of half-power bandwidth of the specimens were measured over a wide range of frequencies from 50 to 3300Hz. Among the specimens, Al-10%$SiC_p$-10%$C_p$ showed the highest loss factor at the mode I, while Mn-Cu alloy showed the highest loss factors at the modes II and III. Consequently, at the mode I the Al-10%$SiC_p$--10%$C_p$ showed the loss factor of 0.00093, which is 2.64 and 1.58 times higher than those of A356 and Mn-Cu alloy, respectively.

• Carbon letters
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• v.26
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• pp.51-60
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• 2018

An electroless deposition method was used to modify the surface properties of rice husk ceramic particles (RHC) by depositing nano-nickel on the surface of the RHC (Ni-RHC). The dry tribological performances of aluminum matrix composite adobes containing different contents of RHC and Ni-RHC particles have been investigated using a micro-tribometer. Results showed that the Ni-RHC particles substantially improved both the friction and wear properties of the Ni-RHC/aluminum matrix adobes. The optimal concentration was determined to be 15 wt% for both the RHC and Ni-RHC particles. The improvements in the tribological properties of aluminum adobes including the Ni-RHC were ascribed to friction-induced peeling off of Ni coating and formation of protection layer on the wear zone, both of which led to low friction and wear volume.

• Journal of Powder Materials
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• v.21 no.1
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• pp.50-54
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• 2014

A powder-in-sheath rolling method was applied to a fabrication of a carbon nano tube (CNT) reinforced aluminum composite. A STS304 tube with an outer diameter of 34 mm and a wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powders and CNTs with the volume contents of 1, 3, 5 vol was filled in the tube by tap filling and then processed to 73.5% height reduction by a rolling mill. The relative density of the CNT/Al composite fabricated by the powder-in-sheath rolling decreased slightly with increasing of CNTs content, but exhibited high value more than 98. The grain size of the aluminum matrix was largely decreased with addition of CNTs; it decreased from $24{\mu}m$ to $0.9{\mu}m$ by the addition of only 1 volCNT. The average hardness of the composites increased by approximately 3 times with the addition of CNTs, comparing to that of unreinforced pure aluminum. It is concluded that the powder-in-sheath rolling method is an effective process for fabrication of CNT reinforced Al matrix composites.

• Journal of the Korean Wood Science and Technology
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• v.16 no.1
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• pp.3-8
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• 1988

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.

• Journal of Korea Foundry Society
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• v.29 no.5
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• pp.204-212
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• 2009

The effects of addition of magnesium only and the simultaneous addition of magnesium and aluminum on the graphite morphology of the cast iron with the composition of 3.6wt.% and 2.5wt.%Si poured into shell stack mold were investigated. The nodularity and mechanical properties of the specimen with smaller cross-section were higher than those with langer one, when copper was not added. When the magnesium only was added, the nodularity was decreased with decreased residual magnesium content and the C. V, graphite was obtained with the magnesium content in the range of 0.010~0.015wt.%. When the magnesium and aluminum were added together, the nodularity was decreased with decreased residual magnesium and increased aluminum contents. When copper was added, the volume fraction of pearlite in the matrix, strength and hardness were higher and elongation was lower for specimen with smaller cross-section. The volume fraction of pearlite, strength and hardness were increased and the elongation was decreased with increased copper content for the specimen with C, V, graphite.