• Design & Manufacturing
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• v.11 no.3
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• pp.1-7
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• 2017

The fabrication process of micro pattern structure with high precision and high aspect ratio using powder injection molding (PIM) is developed. In the PIM process, the metal powder is mixed with the binder systems and the mixture is injected into the metal mold. The injection molded green parts are debinded and sintered to reach final shape and properties. In this method, the optimization of physical properties such as fluidity and strength of the binder system is essential for perfect filling the high aspect ratio micro-pattern. For this purpose, the correlation between the properties of the binder system and feedstock and ${\mu}-PIM$ process was investigated, and a binder system with low viscosity at low temperature(about $110^{\circ}C$) and high strength after cooling was investigated and applied. Employing this process, high precision parts with line type micro pattern structure which has pattern size $160{\mu}m$ and aspect ratio more than 2 can be manufactured.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1394-1403
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• 1998

The study was designed to observe the effect of dietary calcium and fats on plasma cholesterol level, hepatic microsomal fluidity and HMG-CoA reductase activity as well as the excretion of fecal bile acids and neutral sterols in 1, 2-dimethylhydrazine(DMH)-treated rats. Male Sprague Dawley rats, at 7 weeks of age, were divided into 2 groups, 0.3% and 1.0% Ca levels and each group again subdivided into 2 groups of corn oil and perilla oil. Each rat was intramuscularly infused with DMH for 6 weeks to give total dose of 180mg/kg body weight and also fed experimental diet containing 15%(w/w) different fit and Ca(0.3% or 1.0%) for 20 weeks. High dietary calcium(1.0%) did not significantly influence on plasma cholesterol as well as hepatic microsomal fluidity and HMG CoA reductase activity, but significantly reduced the excretion of total bile acid per gram of faces and increased the excretion of total neutral sterol. However, high dietary Ca reduced the excretion of secondary bile acid(deoxycholic and lithocholic acids) which was known as promoter for colon cancer. Perilla oil rich in n-3 ${\alpha}$-linolenic acid significantly decreased plasma cholesterol by increasing hepatic microsomal fluidity compared with corn oil, but did not influence on HMG CoA reductase activity. Perilla oil did not influence on fecal excretion of total and primary bile acids, but reduced the excretion of secondary bile acids. Therefore, it could be recommended to consume more fish product and food rich in calcium and use more perilla oil in meal preparation to prevent from coronary hear disease and colon cancer especially when high fit diet has been practiced. (Korean Nutrition 31(9) : 1394-1403, 1998)

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.41-48
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• 1999

Silica is the most popular materials as a filler of EMC for microelectronic packaging. However, because of its low thermal conductivity, the use of silica is restricted to parts requiring high thermal dissipation. The superior fluidity of EMC can be achieved with a combination of filler size distribution. In this study, physical properties of EMC filled with the crystalline silica(13$\mu\textrm{m}$) which have high fluidity and low cost and the AlN(2 $\mu\textrm{m}$) which have high thermal conductivity and low coefficient of thermal expansion were evaluated by changing the AlN/silica ratios. As a result of the evaluation of physical properties of EMC, the optimum mixing ratio of AlN/crystalline silica was 0.3/0.7. In this condition, binary mixture(AlN/crystalline silica) filled EMC showed superior properties, i.e., in the thermal conductivity, CTE, dielectric constant, flexural strength, and thermal shock resistance without reduction of fluidity.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.12
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• pp.165-172
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• 2019

The aim of the research is to evaluate the influence of various replacing ratios of supplementary cementitious materials(SCMs) such as fly ash(FA), blast furnace slag(BS), and both FA and BS on general properties including segregation resistance as a powder based high fluidity concrete of normal strength grade with water-to-cement ratio 0.40. Specifically, by replacing the SCMs with low density powders, it was assessed that the decreased segregation resistance due to the decreased viscosity by J-ring test. As a result of the experiment, from the general test, the mixtures with SCMs showed increased segregation resistance by increased viscosity as the references, while some segregation was shown from J-ring test due to the decreased density of fresh state mixture related with the capacity of delivering coarse aggregate.

• Composites Research
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• v.33 no.6
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• pp.329-335
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• 2020

In this study, the thermo-rheological behaivors of petroleum pitches with different softening points were studied, and a B-stage phenolic resins/petroleum pitches blends were prepared by adding petroleum pitches to the phenolic resins. As a result, the petroleum pitch with different softening points decreased the fluidity of the petroleum pitch as the Quinoline insoluble (QI) content increased and showed the viscous properties of the solid. In addition, the effect of adding petroleum pitches having different softening points on the thermo-rheological properties of phenolic resins was investigated. When petroleum pitch with a high softening point was added, the fluidity of the phenolic resin was reduced, and the hardening behavior was fast. It was possible to control the curing rate and curing behavior of the phenolic resin by adding petroleum pitches of different softening points. Among them, the phenolic resin mixture to which P-Pitch 2 was added has a higher fluidity than other blends under the same curing temperature condition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.101-107
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• 1993

Zygosaccharomyces rouxii is a salt-tolerant yeast which plays an important role during the ripening stage of soy sauce fermentation. Z. rouxii used in the experiment could grow in YPD (1 % yeast extract, 2% peptone and 2% glucose, pH5.0) medium with 18% (w/v) NaCl, whereas Saccharomyces cerevisiae could only grow in YPD medium with less than 8% NaCl. In the presence of 15% NaCl, Z. rouxii accumulates a large amount of glycerol as a compatible solute within the cells in the exponential phase. It is a characteristic of salt-tolerant yeasts. From the chemical analyses on membrane lipid fluidity, the membrane structure of the cells grown in 15% NaCl was suggested to become more rigid and its fluidity was decreased to keep glycerol within the cells in response to surrounding medium with high concentrations of salt.

• Journal of Korea Foundry Society
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• v.34 no.4
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• pp.130-135
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• 2014

Efforts have been made to develop new silicon-free aluminum casting alloys that possess high electrical and thermal conductivity. In this research Al-Fe-Cu-Mg alloys with various Cu and Mg contents were investigated for their various properties. As the Cu or Mg content was increased, the electrical conductivity gradually decreased, while the tensile strength of the Al-Fe-Cu-Mg alloy tended to be improved. It was found that fluidity was generally inversely proportional to the Cu content, but the alloys containing 1%Mg showed considerably low fluidity, regardless of the Cu content.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.40-41
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• 2020

This study has resulted in the following findings. First, Using more than 30% of GBFS to replace FA enabled bleeding control through improved fluidity. Moreover, it has been confirmed that effective strength and proper quality can be achieved when it was applied as a backfilling material with higher early strength than the base material. Second, When using more than 30% of FNS to replace sand, it was found that adding 0.3~0.35 of the AE agent is effective for bleeding control through improved fluidity. Third, When using more than 30% of both GBFS and FNS in combination, it was found that adding 0.3~0.35 of the AE agent is effective for bleeding control through improved fluidity. Also, it was confirmed that proper mixing of 15~60% of GF secured the effective strength and desired quality as a refiller and joint filler material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.72-73
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• 2021

In this study, the engineering characteristics of CLSM mixed with GBFS and GF were identified to review the applicability as a replacement material and further evaluate the recharge and field applicability as a joint filler material. First, Using more than 30% of GBFS to replace FA enabled bleeding control through improved fluidity. Second, When using more than 30% of FNS to replace sand, it was found that adding 0.25~0.35 of the AE agent is effective for bleeding control through improved fluidity. Third, When using more than 30% of both GBFS and FNS in combination, it was found that adding 0.3~0.35 of the AE agent is effective for bleeding control through improved fluidity. Also, it was confirmed that proper mixing of 15~60% of GF secured the effective strength and desired quality as a refiller and joint filler material.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.147-154
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• 2004

It is the aim of this study to propose the fundamental data for the establishment of the application and qualify standard of the mixed type superplasticizer after investigating and comparing the fluidity of high flowing concrete according to the component ratio of superplasticizer such as naphthalene sulfonated and melamine sulfonated. The results of this study were shown as the followings; 1) The fluidity and adsorption ratio of cement-paste were improved according to the increasing of naphthalene sulfonated component ratio, and apparent viscosity of cement-paste was improved according to the Increasing of melamine sulfonated component ratio. 2) In case of using the granulated blast-furnace slag, the fluidity of cement-paste was considerably good and the adsorption ratio was decreased and in case of using fly-ash, the apparent viscosity and adsorption ratio of cement-paste were improved. 3) The dispersive capacity performance of concrete can be improved by means of the increasing of naphthalene sulfonated component ratio. Also the viscosity and early strength can be improved by means of the increasing of melamine sulfonated component ratio.