• Journal of Powder Materials
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• v.6 no.1
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• pp.88-95
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• 1999

The purpose of this study is to investigate the manufacturing feasibility of WC-Co milling inserts via Powder Injection Molding (PIM) process. WC-Co is used in a wide variety of cutting tools due to its high hardness, stiffness, compressive strength and wear resistance properties. WC-Co parts for a high stress application were conventionally produced by the press and sinter method, which were Iimited to 2 dimensional shapes. Manufacturing WC-Co parts for a high stress application by PIM implies that tool efficiency can be highly improved due to increased freedom is design. P30 grade WC powder (WC-Co-TiC-TaC system) was mixed with RIST-5B133 binder and injection molded into milling inserts (Taegu Tech. Model WCMX 06T 308). The mean grain size of the powder was about 0.8$\mu$m. Injection molded specimens were debound by solvent extraction and thermal degradation method at various conditions. The specimens were sintered at 140$0^{\circ}C$ for 1 hr in vacuum. Carbon content, weight loss, dimensional change, and macro defects of the specimen were carefully monitored at each stage of the PIM process. PIMed WC-Co milling inserts reached 100% full density after sinteing. Its mechanical properties and micro-structures were comparable with the press and sintered milling insert. Carbon content of the sintered WC-Co insert was mainly determained by the atmosphere of thermal debinding. By controlling powder loading and injection molding condition, dimensional accuracy could be obtained within 0.4%. We confirm that PIM can not only be an alternative manufacturing method for WC-Co parts economically but also provide a design freedom for more effieient cutting tools.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.136.2-136
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• 2003

솔잎은 예로부터 민간에서 약용으로 사용되어 간장질환, 비뇨생식기질환, 위장질환, 신경계질환, 순환기질환 및 피부질환 등에 효과가 있다고 알려져 있고 식용으로도 널리 이용하여온 천연식물 자원중의 하나이다. 따라서 본 연구에서는 솔잎 증류액을 가지고 솔잎이 갖는 향기 성분에 대한 분석, 음용수 적합성 시험을 행하였으며, 생리활성 효과를 알아보고자 DPPH 라디칼 소거능 시험, 항돌연변이원성 시험, 세포독성 시험, 유전독성 억제시험을 실시하였다. 실험결과, 향기 성분과 음용수 분석 시험에서는 음용수로 부적합한 성분이 검출되지 않았으며, DPPH 라디칼 소거능 시험에서 RC$_{50}$이 69.9${\mu}\ell$로 높은 항산화 활성을 나타내었다. 또한 항돌연변이원성 시험에서 Salmonella typhimurium TA100 균주에 대하여 시료 농도 200${\mu}\ell$/plate에서 80% 이상의 억제율을 보였다. 세포독성시험 결과, 시료농도 50${\mu}\ell$/well에서 위암세포인 AGS, 간암세포인 HepG2 모두에서 90% 이상의 높은 억제율을 보였다. 그리고 생체내 시험인 유전독성 시험에서는 시료 200${\mu}\ell$/kg에서 72.4%의 비교적 높은 유전독성 억제 효과를 나타내어 기능성 식품의 소재로 사용이 가능 할 것으로 사료된다.

• The Microorganisms and Industry
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• v.15 no.1
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• pp.38-42
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• 1989

Industrial strain Improvement is concerned with developing or modifying microorga-nisms used In production of commercially important fermentation products. The aim is to reduce the production cost by improving productivity of a strain and manipulating specific cilarafteristic such as the ability to utilize cheaper raw materials or resist bacteriophages. The traditional empiri-cal approach to strain improvement is mutation combined with selection and breeding techniques. It is still used by us to improve the productivity of organisms in amino acids. organic acids andenzymes production. The breeding of high L-lysine-producing strain Au112 is one of the outstanding examples of this approach. It is it homoserine auxotroph with AEC, TA double metabolicanalogue resistant markers. The yield reaches 100g/1. Resides, the citric acid-producing organism Aspergillus nuger, Co827, its productivity reches the advanced level in the world, is also the result of a series mutations expecially with Co Y-radiation. The thermostable a-amylaseroducing strain A 4041 is the third example. By combining physical and chemical multations. the strain ,A 4041becomes an asporogenous, catabolite derepressed mutant with rifamycin resistant and methionine, arginine auxotroph markers. The a-amylase activity reaches 200 units/ml. The fourth successful example of mutation in strain improvement is the glucoamylase-producing strain Aspergillus nigerSP56 its enzyme activity is 20,000 units/ml, 4 times of that of the parental strain UV_11. Recently recombinant DNA approach Provides a worth while alternative strategy to Industrial strain improve-ment. This technique had been used by us to increase the thermostable a-amylase production and on some genetic researches.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.113-118
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• 2016

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator-activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at $G_0/G_1$ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of $p21^{CIP1/WAF1}$ and $p27^{KIP1}$. In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.4
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• pp.181-190
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• 2011

Objectives: The purpose of this study is to investigate the clinical effects of heating-conduction acupuncture therapy on anterior talofibular ligament injury induced by acute and chronic ankle sprain. Methods: From April 19, 2010 to May 30, 2011 the 79 outpatients who had admitted to department of oriental rehabilitation medicine, Dae-Jeon oriental medical hospital, Dae-Jeon university with ankle sprain were performed heating-conduction acupuncture therapy on anterior taIofibular ligament injury. To evaluate the efficiency of heating-conduction acupuncture therapy, pain threshold with pressure algometer and visual analogue scale(VAS) were applied before treatment and after 1st, 2nd treatment. Results: 1. The pain threshold and VAS score showed significant improvement on acute subacute, chronic anterior talofibular ligament injury group. 2. The difference in pain threshold and VAS score between acute, subacute, chronic phase group was not significant. Conclusions: Heating-conduction acupuncture therapy has clinical effects of pan reduction on patient with anterior talofibular ligament injury.

• Speech Sciences
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• v.12 no.4
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• pp.183-195
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• 2005

In the present study, we investigated development of verb inflections or endings in 3- to 5-year old Korean-speaking children using 28 action verbs for both comprehension and production tasks. For each verb, a l0-second long motion picture and a sheet of paper with three random-ordered color pictures representing 'before, in the middle of, at the end of' the action were generated. A past tense inflection' -et ta,' two present progressive verb endings '-enta' & '-ko itta.' a future tense ending '-elyeko hanta' were tested. In the comprehension task, children were asked to point to a picture correctly representing the tense of a presented verb. In the production task, children were asked to produce a verb with correctly marking the tense of a presented picture. The order of the two tasks were counterbalanced across the children, and the motion pictures were only presented in the first task. Across the ages, the performance accuracies on both comprehension and production tasks were the highest for the past tense marking followed by two present progressive and future tense markings. For each verb endings, the changes of accuracies across ages were analyzed in both tasks. The types of errors for production tasks were also reported.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.176-179
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• 2005

The increasing demand for high density packaging technologies and the evolution to mixed digital and analogue devices has been the con-set of increasing research in thin film multi-layer technologies such as the passive components integration technology. In this paper, Cu and TaO thin film with RF sputtering was deposited for spiral inductor and MOM capacitor on the $SiO_2$/Si(100) substrate. MOM capacitor and spiral inductor were fabricated for L-C band pass filter by sputtering and lift-off. We are analyzed and designed thin films L-C passive components for band pass filter at 900 MHz and 1.8 GHz, important devices for mobile communication system. Based on the high-Q values of passive components, MOM capacitor and spiral inductors for L-C band pass filter, a low insertion loss of L-C passive components can be realized with a minimized chip area. The insertion loss was 3 dB for a 1.8 GHz filter, and 5 dB for a 900 MHz filter. This paper also discusses a analysis and practical design to thin-film L-C band pass filter.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.335-339
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• 2002

Ba(Mgl-xCox)TaO3[BMCT] ceramics were prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of 1525~$1625^{\circ}C$ for 5hr. in air. The crystal structure of BMCT ceramics was investigated by the XRD. The microstructure of the specimens were observed by SEM. The Microwave dielectric properties of BMCT specimens were investigated as a function of composition and sintering temperature. All BMCT ceramics sintered over 1575$^{\circ}C$ were showed a polycrystalline complex perovskite structure. The density of BMCT (90/10) specimen sintered at $1575^{\circ}C$ was 7.75g/㎤. As the Co contents decreased, the ordering parameter of B-site in BMCT increased. In the case of the BMCT(90/10) ceramics sintered at $1575^{\circ}C$ for 5 hours, dielectric constant, quality factor and temperature coefficient of resonant frequency for microwave dielectrics application were a good value o( 25, 17, 845 at 10㎓ and +2.4 ppm/${\circ}$, respectively.

• Geomechanics and Engineering
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• v.10 no.6
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• pp.793-806
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• 2016

The pozzolanic characteristics of a sludge incinerated into ash were determined in this study. Lime is commonly used as a stabilizer for the treatment of soils, whereas sewage sludge ash (SSA) is often applied with lime to improve soft subgrade soil. In this study, a cohesive soil categorized as A-4 (low-plasticity clay) by AASHTO classifications was mixed with SSA/lime with a 3:1 ratio. Nano-$SiO_2$ was also added to the soil. To identify changes in the workability, strength, permeability, and shear strength of the soft subgrade soil, basic soil tests were conducted, and the microstructure of the treated soil was analyzed. The results indicate that SSA/lime mixtures improve the properties of soft subgrade soil and transform the soil from "poor subgrade soil" to "good to excellent subgrade soil" with a CBR > 8. Additionally, the addition of 2% nano-$SiO_2$ increases the unconfined compressive strength of soft subgrade soil treated with SSA/lime mixture by approximately 17 kPa. However, the swelling of the treated soil increased by approximately 0.1% after the addition of nano-$SiO_2$ and lime. Thus, soil swelling should be considered before lime and nano-$SiO_2$ are applied to soft subgrade soil.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2675-2679
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• 2009

This paper reports the example of headspace mulberry paper bag micro solid phase extraction (HS-MPB-$\mu$-SPE) as a new sampling method for the determination of volatile flavor composition of coriander seeds. Adsorption efficiencies between two configurations of mulberry paper bag were compared, and several parameters affecting the HS-MPB-$\mu$-SPE were investigated and optimized. The optimized technique uses an adsorbent (Tenax TA, 0.1 mg) contained in a mulberry paper bag of front configuration where fine surface was outside, and minimal amount of organic solvent (0.6 mL). Linalool and $\gamma$-terpinene were found as abundant flavor compounds from coriander seeds. The limit of detection (LOD) and the limit of quantitation (LOQ) for linalool of major flavor in coriander seeds were 10.3 ng/mL and 34.4 ng/mL, respectively. The proposed method showed good reproducibility and good recovery. The HS-MPB-$\mu$-SPE is very simple to use, inexpensive, requires small sample amounts and solvent consumption. Because the solvent for extraction is reduced to only a very small volume, there is minimal waste or exposure to toxic organic solvent and no further concentration step.