• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1493-1494
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• 1998

We have investigated the influence of Ti/Ba mole ratio in the characteristics of the modified $BaTiO_3$ systems with Ca addition. The specimens were fabricated with variations in Ti/Ba mole ratio between 0.995 and 1.01, and sintered in the temperature range between $1325^{\circ}C$ and $1375^{\circ}C$. When Ti/Ba mole ratio was 1.005 and sintering temperature was $1350^{\circ}C$, the breakdown voltage shows 260[V /mm].

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.75-76
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• 2018

MiDF, Micro Defect Free concrete, is the concrete made for high strength development by minimizing the defects such as micro pore and ITZ. Since MiDF exhibits strength through hydro-thermal synthesis reaction, it is essential to select the optimum C/S mole ratio. In this study, the basic characteristics of MiDF were evaluated by controlling the C/S mole ratio by SF and QP.

• 대한화학회지
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• 제20권6호
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• pp.525-532
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• 1976

CO2/KOH catalysis에 의해 2-pyrrolidone과 ${\varepsilon}$-caprolactam의 음이온 중합을 시도하였으며 이 polymer의 물리적 성질을 조사하였다. 2-Pyrrolidone 중합의 경우는, KOH의 농도가 8mole%이상이고 $CO_2/KOH$ mole ratio가 0.45일 때 percent conversion이 가장 높았으며 $50^{\circ}C$가 최적의 온도임을 알았다. ${\varepsilon}$-Carprolactam의 중합에 있어서는 80 ∼ $90^{\circ}C$에서 percent conversion이 낮았고, 150 ∼ $180^{\circ}C$의 온도에서는$ CO_2/KOH$ mole ratio에 크게 관계없이 높은 percent conversion을 얻을 수 있었다. 이들 polymer의 고유점도는 대략 2.0 ∼ 5.0dl/g의 높은 값이었다.

• 한국세라믹학회지
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• 제28권5호
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• pp.373-382
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• 1991

The effect of Ca/P mole ratio (Ca/P=1.60, 1.67, 1.75) in the initial solution on the mechanical properties of alumina added hydroxyapatite was investigated. Hydroxyapatite was synthesized by precipitation method using Ca(NO3)2$.$4H2O and (NH4)2HPO4 as starting materials and 5 wt% of ${\alpha}$-Al2O3 was added to precipitation solution. The powder was calcined at 800$^{\circ}C$ and sintered at 1,150∼1,400$^{\circ}C$ under water vapor atmosphere. With the increasing of Ca/P mole ration in the initial solution, the amount of tricalcium phosphate formed from the decomposition of hydroxyapatite reduced and the sinterability and mechanical properties were increased. The bending strength and Vickers hardness of the specimen sintered at 1,300$^{\circ}C$ with the Ca/P mole ratio of 1.75 in the initial solution were 230 MPa and 650 kg/$\textrm{mm}^2$, respectively. The improvement of mechanical properties was attributed to not only the effect of Ca/P mole ratio but also the strengthening of sintered body by Al substitution for P ions.

• 한국대기환경학회지
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• 제11권2호
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• pp.171-178
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• 1995

The hydrodesulfurization (HDS) of dibenzothiophene (DBT) were performed simultaneously over CoPtMo/LaY catalyst under high H$_{2}$ pressure. The structure and physical properties of this catalyst were characterized using XRD, IR and surface area analyzer. The origin of acid site was mainly Bronsted. The structures of impregnated molybdenum and platinum were deactivated by DBT to MoS$_{2}$ and PtS, respectively. The activities of the HDS and the hydrocracking increased with increasing temperature and pressure. They decreased with increasing the DBT mole ratio(DBT/n-heptane). They remained constant with increasing the H$_{2}$/H.C. mole ratio. With increasing pressure and DBT mole ratio, the products of secondary cracking increased. To perform simultaneous HDS and hydrocracking effectively, the optimum condition were 500.deg.C, 4MPa.

• 대한화학회지
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• 제21권6호
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• pp.440-444
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• 1977

$CS_2$/KOH catalysis를 이용해서 ${\varepsilon}$-caprolactam의 음이온중합을 시키고 percent conversion과 점도를 측정하였다. $80^{\circ}C,\;105^{\circ}C$의 비교적 낮은 온도에서는 $CS_2$/KOH mole ratio가 0.5일때 percent conversion이 가장 높았으며 또 KOH의 당량에 비례하여 percent conversion도 증가하였다. 그러나 $130^{\circ}C,\;155^{\circ}C$로 중합온도를 상승함에 따라 $CS_2$/KOH mole ratio와 KOH양에는 크게 관계없이 높은 percent conversion을 얻을 수 있었다. 그리고 30分 정도의 짧은 중합시간으로도 $80{\%}$ 이상의 높은 percent conversion을 얻을 수 있었다.

• 한국세라믹학회지
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• 제33권10호
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• pp.1163-1169
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• 1996

The effects of borax on the phase formation of C2S, C4A3 and $\alpha$'-C2S phases. It has negative effects on formation of C4A3 And it lowers the forming temperature of C4AF. It also has been found that borax improves the clinkerization of MBC. In the MBC clinker with borax 3% C2S have larger and more irregular shapes, larger C/S mole ratio and C4A3 have smaller size larger C/ molr ratio than in the clinker without borax.

• 한국세라믹학회지
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• 제30권2호
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• pp.85-92
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• 1993

Oxynitride glasses in Na-Ca-Si-O-N system were prepared by melting at 135$0^{\circ}C$ for 2 hours in N2 gas. The effects of Si/Na mole ratio and the various Si3N4 contents were investigated. Stable oxynitride glasses can be obtained up to 9wt.% Si3N4 content in case the Si/Na mole ratio was 2.12 and 1.62, but $\beta$-Si3N4 was precipitated at 9wt.% Si3N4 content in case the Si/Na mole rtio was 1.12. Density (p), chemical durability, hardness (Hv), and fracture toughness (KIC) increased with increasing Si3N4 content. In cae the Si/Na mole ratio was 1.12, the increment of properties was remarkable but hardness and fracture toughness did not increase no longer owing to precipitation of $\beta$-Si3N4.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.100-102
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• 2001

In this paper, the piezoelectric and dielectric properties of $Pb(Zr_xTi_{1-x)O_3$ - $Pb(Co_{1/3}Nb_{1/3})O_3)$ piezoelectric ceramics have been investigated as a function of Zr/Ti mole ratio. From the results, when Zr/Ti mole ratio is 49/51, electromechanical coupling coefficient($k_p$), piezoelectric strain constant($d_{33}$) mechanical quality factor($Q_m$), and Permittivity(${{\varepsilon}_{33}}^T/{\varepsilon}_0$) is 64[%], 469[PC/N], 360 and 2000, respectively. Morphotropic Phase Boundary is Zr/Ti mole ratio(49/51) from XRD analysis. Also. From SEM observation, when sintering temperature is 1150[$^{\circ}C$], grain size is about $1{\sim}2[{\mu}m]$ and maximum sintering density is 7.85[$g/cm^3$].

• KSBB Journal
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• 제21권4호
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• pp.255-259
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• 2006

생체 적합성이 우수한 히아루론산과 생분해성이 우수한 폴리락타이드의 이량체인 락타이드의 혼합 몰비, 가교제 EDC 농도, 가교 온도 등의 반응 조건을 변화시켜 생체적합성 고분자막을 제조하였다. 히아루론산에 대한 락타이드의 혼합 몰비가 증가할수록 수용액상에서의 분해속도는 감소하였다. 합성된 고분자막을 ethylene oxide gas로 멸균 한 후 세포배양배지를 첨가하여 $37^{\circ}C$에서 200 rpm으로 24 시간동안 교반하면서 침출물을 추출한 다음 NIH/3T3 섬유아세포에 대한 세포독성을 측정하였다. EDC 농도 10% 조건에서 히아루론산에 대한 락타이드의 혼합 몰비가 5 또는 10에서는 세포독성을 나타내지 않았지만 몰비 13에서는 11% 정도의 성장저해를 나타내었다. 혼합 몰비를 10으로 고정하고 가교 온도 $15^{\circ}C$에서 EDC의 농도를 5%, 10%, 20%로 변화시켜을 때, EDC 농도가 20%인 경우에서만 12% 정도의 성장저해를 나타내었다. 혼합 몰비 10, EDC 농도 10% 조건에서 가교 온도를 $15^{\circ}C,\;25^{\circ}C,\;28^{\circ}C$로 변화시켰을 때, 가교 온도에 따른 세포독성은 나타나지 않았다. 따라서 락타이드와 히아루론산의 몰비와 EDC의 농도를 조절함으로써 인체 내에서 분해 속도를 조절할 수 있는 새로운 생체적합성 고분자막을 제조할 수 있을 것으로 사료된다.