• 약학회지
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• 제34권3호
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• pp.155-160
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• 1990

An oral adhesive tablet of acyclorir [9-(2-hydroxyethoxymethyl) guanine] for herpetic stomatitis was prepared and its physical properties were evaluated. 300 mg weighed tablets containing 30 mg of acyclovir were prepared with six kinds of polymers from direct compression, and the stickiness, fracture resistance and dissolution in pH 6.8 buffer solution were tested. HPMC and MC showed good stickiness and fracture resistance, and their dissolution rates were significantly different from each other. Three factors-HPMC:MC ratio, acyclovir content, compression force-were chosen as an important factor of manufacture and factorial analyses for these three factors were carried out. Eight kinds of formulations from different combination of three factors were prepared and tested in stickiness, fracture resistance and dissolution in pH 6.8 buffer solution. Dissolution rate was significantly affected by polymer ratio, fracture resistance was affected by compression force, and stickiness was not significantly affected by acyclovir content and polymer ratio.

• 한국건축시공학회지
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• 제17권5호
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• pp.437-444
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• 2017

개량 아스팔트 방수시트 위에 폴리 우레탄 도막방수재가 도포되는 복합방수공법의 경우 시공성 향상을 위하여 도막 방수재에 유기용제를 희석해 사용하고 있지만, 유기용제가 폴리 우레탄 도막방수재의 완전 경화 전에 전부 휘발되지 못하고 시트재와 도막재 사이에 잔류하게 되고 이는 아스팔트 층을 융해시켜 방수층 손상 및 누수문제를 발생시켰다. 이에 용제에 의한 융해 문제를 개선하기 위해 내용제성이 강한 PA 필름을 개량 아스팔트 시트에 코팅(적층)하였고, 그 결과 융해에 대한 안전성을 육안을 관찰하였고, SEM 분석, EDX 분석을 통하여 PA 필름에 대한 내용제성을 정량적으로 확인하였다.

• 한국재료학회지
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• 제11권4호
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• pp.266-271
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• 2001

Al-Cu-Mn 주조합금의 응력부식균열 저항성에 미치는 Cd첨가의 영향을 C-ring test와 전기전도도 시험을 통하여 조사하였다. Cd첨가량이 증가함에 따라 전기전도도가 증가하였고 SCC 저항성도 증가하였다. SCC 시험결과 균열이 입계를 따라 전파되는 입계파괴가 일어났으며, 파면은 취성파괴양상을 나타내었고, 입계를 따라 조대 석출물과 무석출대가 나타난 것으로 보아서 이 합금의 SCC 기구는 anodic dissolution model이라고 판단된다. Cd을 첨가하지 않은 경우 최대경도값은 127Hv였으나, Cd을 첨가한 경우 최대경도값은 138∼146Hv로 증가하였다.

• Corrosion Science and Technology
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• 제5권1호
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• pp.1-4
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• 2006

Martensitic stainless steel is used when mechanical properties such as high tensile strength and hardness are required. Medium carbon-contained martensitic stainless steel which contains more than 0.2 wt% of carbon should be heat-treated and quenched at the temperature where undissolved carbides are totally dissolved into the matrix. In particular, the dissolution and reprecipitation behaviors of various forms of carbides are affected by such parameters as heating rate, heating temperature, duration time and cooling rate. This study is to investigate the effects of heat treatment parameters of 14Cr-3Mo martensitic stainless on corrosion resistance and phase transformation in relation to the dissolution and reprecipitation of carbides.

• 한국재료학회지
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• 제12권6호
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• pp.436-441
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• 2002

Effect of Sn addition on the stress corrosion cracking(SCC) resistance of the Al-Cu-Mn cast alley was investigated by C-ring teat and electrical conductivity measurement, The electrical conductivity and SCC resistance increased by Sn addition. The alley containing 0,10%Sn showed maximum electrical conductivity and the best SCC resistance. At the same composition, the electrical conductivity and SCC resistance increased from peak aged condition to ever aged condition. The PFZ and coarse precipitates along the grain boundary were observed from TEM micrographs. The fracture mode of the alloy was confirmed as intergranular type and showed brittle fracture surface. The SCC mechanism of the alloy was concluded as the anodic dissolution model, The maximum hardness was increased from 130Hv in the Sn-free alloy to 156Hv in the 0.10%Sn added alloy.

• 한국세라믹학회지
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• 제45권10호
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• pp.594-599
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• 2008

Hydroxyapatite(HA) was prepared from waste tuna bone, and its sintering property and dissolution behavior were investigated. Tuna bone derived-HA powder consisted of mainly HA and small amount of MgO. Porous HA ceramics with sintered density of 79% was obtained by pressureless sintering at $1200^{\circ}C$. Meanwhile, HA ceramics prepared by hot pressing at $1000^{\circ}C$ showed dense microstructure with sintered density of 95%. Immersion test revealed that both porous and dense HA ceramics were stable in liquid environment without distinct evidence of surface dissolution. It may be assumed that the presence of Mg in tuna bone-derived HA may improve dissolution resistance of HA.

• 한국지반공학회논문집
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• 제27권12호
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• pp.17-25
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• 2011

흙입자의 구조는 흙을 구성하는 용해성 입자의 용해작용, 건조작용 그리고 고결화 현상과 같은 특정요인에 의해 영향을 받으며 입자구조의 변화는 흙의 역학적 거동에 큰 영향을 미친다. 본 논문에서는 흙속에 포함된 용해성입자의 용해작용이 전단강도에 미치는 영향을 조사하였다. 직접전단실험을 위해 소금과 모래로 구성된 혼합재를 이용하여 시료를 조성하고 전체시료에 대한 용해성 입자의 부피비를 조절하면서 실험을 수행하였으며 실험과 동일한 조건하에 서 수치해석을 수행하였다. 입자의 소실과정을 위해 실험에서는 소금-모래 혼합재를 포화시켜 소금을 용해시켰으며 수치해석에서는 용해성 입자의 크기를 줄이는 것으로 용해과정을 모사하였다. 실험결과, 용해성 입자의 부피비가 증가할수록 내부마찰각은 감소하였고, 시료의 수직변형은 팽창거동에서 수축거동으로 변화하였다. 수치해석은 실험 결과와 유사한 거시적 거동을 보여주었다. 미시적관점에서, 입자가 용해됨에 따라 간극비의 증가, 접촉점 수의 감소, 전단접촉력의 증가, 접촉력 연결고리의 이방성에 의해 새로운 입자구조가 생성됨을 보여주었다. 이러한 미시적 거동의 변화는 입자의 용해작용 후 전단거동에 영향을 주게 된다. 본 연구에서는 기초나 지반구조물의 설계와 시공 시 지반재료의 용해에 따른 전단강도을 고려해야 함을 보여준다.

• 환경위생공학
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• 제18권2호
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• pp.1-8
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• 2003

The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of molybdenum wire which used as the center supporter, reactions occur in room temperature. The results were as follows : 1. In the FL/10-A type: Dissolution-reaction Time was 50Min., C.R.(Coil resistance) was $9.27{\Omega}(St.{\;}:{\;}9.2{\pm}0.22{\Omega})$, P.W.(Piece weight) was $10.59mg(St.{\;}:{\;}10.5{\pm}0.26mg)$. In the FL/15-D type: Dissolution-reaction Time was 55Min., C.R. was $6.39{\Omega}(St.{\;}:{\;}6.38{\pm}0.02{\Omega})$, P.W. was $16.7mg(St.{\;}:{\;}16.5{\pm}0.3mg)$. In the FL/20-H type: Dissolution-reaction Time was 45Min., C.R. was $4.7{\Omega}(St.{\;}:{\;}4.6{\pm}0.3{\Omega})$, P.W. was $20.8mg(St.{\;}:{\;}20{\pm}1.5mg)$. In the FL/20-C type: Dissolution-reaction Time was 60Min., C.R. was $4.5{\Omega}(St.{\;}:{\;}4.6{\pm}0.3{\Omega})$, P.W. was $19.8mg(St.{\;}:{\;}19{\pm}1.0mg)$. 2. In the GLS-230/40-B type: Dissolutiona-reaction Time was 45Min., C.R. was $105.1{\Omega}(St.{\;}:{\;}104{\pm}2.6{\Omega})$, P.W was $6.37mg(St.{\;}:{\;}6.3{\pm}0.16mg)$. In the GLS-230/60-F type: Dissolution- reaction Time was 45Min., C.R. was $65.92{\Omega}(St.{\;}:{\;}65{\pm}1.62{\Omega})$, P.W. was $11.91mg(St.{\;}:{\;}11.8{\pm}0.29mg)$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.918-921
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• 2000

Micro-machining, one of the non-traditional machining techniques, can achieve a wanted shape of the surface using metal dissolution with electrochemical reaction and can be applied to the metal such as high tension, heat resistance and hardened steel. The workpiece dissolves when it is positioned close to the tool electrode in electrolyte and the current is applied. Traditional machining has been used in the industries such as cutting, deburring, drilling and shaping. The aim of this work is to develop Micro-machining techniques for micro shape by establishing appropriate machining parameters of micro-machining

• 열처리공학회지
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• 제23권2호
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• pp.90-95
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• 2010

The effects of grain size on the corrosion resistance of 429EM ferritic stainless steels for automobile exhaust system were investigated. Using specimens held at maximum service temperature of $950^{\circ}C$ for 10~70 hours, electrochemical polarization tests were conducted. While corrosion current density, $I_{corr}$, was influenced little by grain size, pitting potential, $E_p$, was increased with an increase of grain size. Sensitizaton at grain boundary occurred when the specimen were held at $950^{\circ}C$ for above 50 hours because of the dissolution of precipitates and grain coarsening.