• 대한화학회지
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• 제29권3호
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• pp.233-238
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• 1985

비다공성 및 다공성 폴리스티렌 디비닐벤젠 공중합체를 합성하고, 이것을 클로로메틸화 한후, 메틸아민으로 아미노화하여 약염기성 음이온교환수지인, 50∼100mesh의 비다공성, N-APSTDVB와 다공성, P-APSTDVB를 만들었다. 합성한 이들 음이온교환수지를 적외선 흡수스펙트럼으로 확인하였다. 이들 음이온교환수지의 최대 이온교환용량은 4.86meq/g이었다. 다공성 폴리스티렌 디비닐벤젠 공중합체, P-APSTDVB의 세공용적은, 디비닐벤젠의 볼륨퍼센트를 30%로 하였을 때, X$_{diluent}$의 증가에 따라서 증가하였다. 또한 X$_{diluent}$의 양을 0.5로 일정하게 하였을때, P-APSTDVB공중합체의 세공용적은, 디비닐벤젠의 볼륨퍼센트가 증가함에 따라 증가하였다. 디비닐벤젠의 퍼센트를 8%로 일정하게 하고, X$_{heptane}$을 0.5로 하였을 때, 합성한 공중합체와 음이온교환수지의 세공용적은, P-PSTDVB >P-APSTDVB >N-PSTDVB순으로 감소하였다. 여러 농도하에서의, 여러종류의 알코올 수용액중에서의 N-APSTDVB음이온교환수지에 대한 붕산의 분포계수가, 또한 논의되었다.

• 멤브레인
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• 제24권2호
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• pp.158-166
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• 2014

본 연구에서는 PVDF 중공사막을 열유도상분리와 연신의 복합공정에 의해 제조하였으며, 연신비에 따른 분리막의 구조 및 물성을 분석하였다. 이 분리막 제조의 메카니즘은 액-액 상분리에 기초하며, 최종 중공사막은 bicontinuous한 구조와 연신에 의해 fibrill 구조를 가지게 되어, 구정(spherulite)구조를 갖는 고-액 상분리막과 bicontinuous한 구조만을 갖는 액-액상분리막과 차별화된다. 우선, TIPS공정을 통해, gamma-butyrolacton, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) 등을 단일 혹은 이들을 조합한 혼합 diluent로 사용하여, 냉각조건, PVDF와 희석제의 함량을 조절하면서 중공사막 전구체를 제조하고, 후속공정인 연신에 의해 최종적으로 중공사막의 외부표면을 porous하게, 혹은 dense하게 만들 수 있었다. 연신된 중공사막을 에탄올에 추출, 건조한 후 SEM을 통하여 pore 구조의 변화를 관찰하였으며, 수투과량, 다공도, 기공 크기, 표면 거칠기, 인장강도 등의 변화를 분석하였다.

• Elastomers and Composites
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• 제37권2호
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• pp.79-85
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• 2002

2몰% 에틸가지를 포함하는 에틸 가지화 폴리에틸렌[PE(2)]과 에틸렌-프로필렌 몰비가 50:50 으로 같지만 입체규칙성이 다른 랜덤-에틸렌-프로필렌 고무(r-EPR), 교호-에틸렌-프로필렌고무(alt-EPR) 및 이소탁틱-교호-에틸렌-프로필렌 고무(iso-alt-EPR)를 에틸렌-프로필렌 고무의 입체규칙성의 차이에 대한 혼화성과 물성의 차이를 조사하기 위하여 혼합하였다. 혼합된 블렌드의 결정화도는 고무상 EPR 성분의 증가에 따라 감소되었으며, EPR의 입체규칙성이 작을수록, 혼합조성의 증가할수록 감소하였다. 열역학적 interaction parameter(x) 값은 3가지 블렌드 모두 거의 영에 가까운 값을 나타내어 본 블렌드계는 PE(2)의 녹는점 가까이 또는 그 이상에서 상호간 섞일 것으로 판단되었다. 녹는점($T_m$)과 결정화온도($T_c$)의 측정에서부터 세가지 블렌드는 혼합조성과 입체규칙성에 관계없이 직선관계를 보여주어 이 블렌드계의 PE(2)의 용융거동은 주로 희석효과(diluent effect)에 기인함을 알 수 있었다. Small angle light scattering(SALS) 방법에 의한 PE(2)의 spherulite의 크기는 세가지 블렌드계가 EPR의 혼합비 증가에 따라 증가하였으며, 같은 혼합비에서는 r-EPR>alt-EPR>iso-alt-EPR> 순서로 증가하였다.

• 대한화학회지
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• 제29권3호
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• pp.283-286
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• 1985

비다공성 및 다공성 4-비닐피리딘디비닐벤젠 이온교환수지를, 서스펜션 중합방법으로 합성하였다. 합성한 이들 수지들은 적외선 흡수스펙트럼을 통하여 확인하였다. 다공성수지의 세공용적과 세공스펙트럼들은 수은 Porosimeter를 사용하여 측정하였다. 다공성 4-비닐피리딘디비닐벤젠 이온교환수지, P-4VPDVB, 50-100 mesh의 세공용적과 세공크기에 미치는 diluent와 %DVB의 영향이 논의되었다. 그리고 이들 비다공성 및 다공성 4-비닐피리딘 디비닐벤젠 수지들의 이온교환용량은 5.0meq/g이었다.

• 한국염색가공학회지
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• 제15권4호
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• pp.57-64
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• 2003

Poly(ethylene-co-vinyl acetate)(EVA) microspheres were prepared by a thermally induced phase separation. The microsphere formation occurred by the nucleation and growth mechanism in the metastable region. The diluent used was toluene. The microsphere formation and growth was followed by the cloud point of the optical microscope measurement. The microsphere size distribution, which was obtained by SEM observation and particle size analyzer, became broader when the polymer concentration was higher, the content of vinyl acetate in EVA copolymer was higher, and the cooling rate of EVA copolymer solution was lower.

• 한국세라믹학회지
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• 제42권9호
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• pp.607-612
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• 2005

The effect of MgO diluents in combustion synthesis of $TiB_2$ nano particles was investigated. The reaction $TiO_2\;+\;B_2O_3\;+\;xMg\;{\rightarrow}\;TiB_2\;+\;5MgO$ was used to synthesize $TiB_2$ nano particles. The combustion velocity was measured to examine the relation between the reaction temperature and the morphologies of particles. The diluent MgO did not react with the reactants and played a role to decrease combustion temperature. As the MgO diluents contents increased, the particles with the smaller size and the narrower size distribution were synthesized. At the condition of 6 mole of MgO, the combustion wave velocity was about 5 cm/see and the synthesized particles showed the size of 60 nm with narrow size distribution.

• 한국분말재료학회지
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• 제11권4호
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• pp.333-340
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• 2004

In this study, tantalum powder has been producted by MR-EMR combination process. MR-EMR combination process is a method that is able to improve demerits of MR(metallothermic reduction) and EMR(electronically mediated reaction) process. This study examined the characteristics of powder with the amount of reductant excess using $K_2$TaF$_{7}$ as feed materials, Na as a reductant and KCl/KF as a diluent. In addition, this study examined acid treatment that affect the high purification of powder. The impurities contained in powder was removed in various conditions of acid treatment. The total charge passed through external circuit and average particle size(FSSS) were increased with increasing amount of sodium excess. The proportion of fine particle(-325mesh) was decreased with increasing amount of sodium excess. The yield was improved from 70％ to 76% with increasing amount of sodium excess. Considering the impurities, charge, morphology, particle size and yield, an amount of sodium excess of 10wt% were found to be optimum conditions for MR-EMR combination process.s.

• 약학회지
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• 제18권4호
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• pp.236-242
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• 1974

Extrusion-spheronization processing combination was used to produce spherical granules with experimental formulations which contain microcrystalline cellulose as a diluent. The produced granules were compared on the basis of the following physical properties ; (a) bulk density, (e) porosity, (f) friabillity and (g) dissolution rate. With the specific experimental formulations used in this study, the increased plate rotational speeds of Marumerizer (400-1200rpm) produced continually more spherical material and also the obtained data indicated that the particle size distribution and dissolution rate depend upon the amount of microcrystalline cellulose used. As a result, the spherical granule preparation with microcrystalline cellulose has good properties in flow rate, packing propertyu and friability and offers a suitable method of granule preparation in pharmaceutical industry.

• 동굴
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• 제71호
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• pp.5-11
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• 2006

A theoretical investigation of the solid phase mechanochemical synthesis of nano sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3 mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano TlCl by dilution of initial (2NaCl+$Tl_2SO_4$) mixture with the exchange reaction product (diluent,$zNa_2SO_4$, z=z*=11.25) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano TlCl obtained experimentally were compared with those for the model reaction KBr+TlCl+zKCl=(z+1) KCl+TlBr (z=z1*=13.5), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.405-406
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• 2005

A theoretical investigation of the solid-phase mechanochemical synthesis of nano-sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3-mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact-friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano-TlCl by dilution of initial (2NaCl + $Tl_2SO_4$) mixture with the exchange reaction product (diluent, $zNa_2SO_4$, $z=z^*=11.25$) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano-TlCl obtained experimentally were compared with those for the model reaction KBr + TlCl + zKCl = (z + 1) KCl + TlBr ($z=z_l^*=13.5$), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.