고압연소 소결에 의해 제조된 Ni-Aluminide 계 금속간화합물의 치밀화 및 내마모 성질

양범석,원창환,고석권,정중채,윤기석 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.7

The superior oxidation-resistance, wear-resistance and creep-resistance make Ni-aluminide intermetallic compounds have merits for high-temperature applications. Simultaneous synthesis and densification of NiAl and Ni₃Al from elemental Ni and Al powders was investigated. Combustion synthseis was carried out under the uniaxial compressive pressure and preheating of metal mould die. It was shown that both the compressive pressure and preheating of metal mould die strongly affect the density, the grain size, the hardness and the wear loss of NiAl and Ni₃Al product. A relative density of NiAl and Ni₃Al products as much as 99.8% was achived under compressive pressure of 275㎫ and preheating temperature of 600℃.

쥐의 자궁에서 알카리성 포스파타아제의 분리 및 그 효소의 특성에 관한 연구

양범석,양철학 ( Beom Seok Yang,Chul Hak Yang ) 생화학분자생물학회 1985 BMB Reports Vol.18 No.1

Alkaline phoshatase (orthophosphoric monoester phosphohydrolase EC 3.1.3.1) which hydrolyzes a variety of monophosphate esters was purified from rat uterus, using butanol extraction, acetone precipitation, gel filtration on Sephadex G-150, affinity chromatography on Concanavalin A-Sepharose 4B, and isoelectric focusing. This enzyme has the molecular weight of 560,000 daltons by gel filtration and it is very unstable below pH 6.0 and the most stable between pH 8-9. This enzyme shows pH optimum shift of 0.62 pH with 10-fold increase in substrate concentration. Ionic strength in the reaction buffer affects the enzyme activity that is, increase in ionic strength decreases Km and increases the V_(max). The log V_(max) is primarily dependent on the square root of ionic strength. From the thermostability study, it may be concluded that alkaline phosphatase from rat uterus is a different isoenzyme from that of other rat tissues like placenta, liver, and intestine. Among divalent cation, Mg^(2+) is a good activator for the enzyme and Ca^(2+) shows an activation only when its concentration is more than 100 mM. The optimum pH of enzyme activation by Mg^(2+) does not coincide with the optimum pH of enzyme activity. This enzyme has a multiple pI values of pI 6.5-7.1 from the isoelectric forcusing. This enzyme strongly binds to DEAE-Sephadex not by the normal charge to charge interaction but by an uncertain interaction between the enzyme and DEAE-ligand. The bound enzyme activity is not eluted even with the high ionic strength buffer containing 1.2 M NaCl. But it can be eluted by the 1 M solution of 2-amino-2-methyl-1, 3-propanediol.

수열합성법으로 제조된 PZT 분말의 특성에 미치는 광화제 농도와 출발물질의 영향

양범석,윤기석,박영철,원창환,Yang, Beom-Seok,Yun, Ki-Seok,Park, Young-Chul,Won, Chang-Whan 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.11

The effect of reaction parameters in the characteristic of $Pb(Zr_{0.52} Ti_{0.48})O_3$ powders by hydrothermal process was investigated in this study. In the preparation of PZT, the types of starting material and concentration of mineralizer on phase fraction and morphology was investigated respectively. Regardless the types of Pb precursor, PZT was able to synthesize ranging from 7 to 20 on KOH concentration and from 13.01 to 13.55 on pH of solution. The particle size of the PZT powders can be controlled by the mineralizer concentration and various types of precursor.

수열합성법으로 제조된 PZT 분말의 특성

양범석,이혁희,원창환,Yang, Beom-Seok,Lee, Huk-Hee,Won, Chang-Whan 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.7

Conditions for formation of perovskite Pb(Zr$_{0.52}$Ti$_{0.48}$)O$_{3}$ phase by the hydrothermal synthesis are investigated. Pb(Zr$_{0.52}$ Ti$_{0.48}$)O$_{3}$ ceramics were synthesized by hydrothermal process above 180$^{\circ}C$ for 2 h reaction using 5$\~$30 M KOH solution as a mineralizer. Particle size increases in proportion to the mineralizer concentration. As a result of EOX analysis, PZT powders synthesized using 50 M of KOH as a mineralizer were considered as 2.42 mol$\%$ K doped-PZT powders. And 2.42 mol$\%$ K doped-PZT has much higher mechanical quality factor than undoped PZT ceramics. The sintering properties showed 7.987 g/cm$^{3}$ of sintered density and 3$\~$4 $\mu$m of grain size.

Alkaline Phosphatase from Rat Uterus: Purification and Characterization

양범석,양철학,Yang, Beom-Seok,Yang, Chul-Hak 생화학분자생물학회 1985 한국생화학회지 Vol.18 No.1

알카리성 포스파타아제를 쥐의 자궁으로부터 부탄올 추출, 아세톤 침전법, 세파텍스 G-200을 이용한 젤 크로마터그래피법, 콘카나발린 A를 이용한 흡착 크로마토그래피법, 그리고 등전초점화법을 이용하여 정제하였다. 이 효소의 분자량은 560,000달톤이었고 pH 6 이하에서는 매우 불안정하나 pH8-9 사이에서는 가장 안정하였다. 열에 대한 안정도로 비교할 때 쥐 자궁의 알카리성 포스파타아제는 태반의 알카리성 포스파타아제와는 다른 효소였다. 효소활동도의 최적 pH는 기질의 농도가 증가 함에 따라 증가한다. 즉 10배의 기질 농도 증가에 대해 최적 pH는 0.62씩 증가한다. 반응용액의 이온강도는 효소 활동도에 영향을 미친다. 즉 이온강도가 증가함에 따라 $K_m$값은 감소하고 $V_{max}$는 증가한다. log $V_{max}$는 이온강도의 제곱근에 비례하는데 이것은 E-S 복합체에서 생성물로 가는 반응경로에 이온반응이 있음을 암시한다. 이 효소의 등전점은 pH 6.5-7.1사이에 넓게 분포하며 pH 6.8이 주둥전점이다. 이 효소는 $Mg^{2+}$ 이온에 의해 그 활동도가 크게 증가되나 효소활동도의 최적 pH는 서로 일치하지 않는다. 이 효소는 DEAE리간드에 강하게 부착되는데 이는 일반적인 단백질과 리간드 사이의 정전기적 인력에 의한 결합이 아니기 때문에 매우 높은 이온강도를 가지는 완충용액으로서도 리간드와 단백질을 분리할 수 없으며 단지 2-아미노-2-메칠-1, 3-프로판디올 1 M 용액으로 이 효소를 DEAE 리간드로 부터 분리할 수 있다. Alkaline phoshatase (orthophosphoric monoester phosphohydrolase EC 3.1.3.1) which hydrolyzes a variety of monophosphate esters was purified from rat uterus, using butanol extraction, acetone precipitation, gel filtration on Sephadex G-150, affinity chromatography on Concanavalin A-Sepharose 4B, and isoelectric focusing. This enzyme has the molecular weight of 560,000 daltons by gel filtration and it is very unstable below pH 6.0 and the most stable between pH 8-9. This enzyme shows pH optimum shift of 0.62 pH with 10-fold increase in substrate concentration. Ionic strength in the reaction buffer affects the enzyme activity that is, increase in ionic strength decreases $K_m$ and increases the $V_{max}$. The log $V_{max}$ is primarily dependent on the square root of ionic strength. From the thermostability study, it may be concluded that alkaline phosphatase from rat uterus is a different isoenzyme from that of other rat tissues like placenta, liver, and intestine. Among divalent cation, $Mg^{2+}$ is a good activator for the enzyme and $Ca^{2+}$ shows an activation only when its concentration is more than 100 mM. The optimum pH of enzyme activation by $Mg^{2+}$ does not coincide with the optimum pH of enzyme activity. This enzyme has a multiple pI values of pI 6.5-7.1 from the isoelectric forcusing. This enzyme strongly binds to DEAE-Sephadex not by the normal charge to charge interaction but by an uncertain interaction between the enzyme and DEAE-ligand. The bound enzyme activity is not eluted even with the high ionic strength buffer containing 1.2 M NaCl. But it can be eluted by the 1 M solution of 2-amino-2-methyl-1, 3-propanediol.

Effects of Sr on the Characteristics of PZT Ceramics Prepared by Hydrothermal Process

양범석,신창윤,원창환 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.11

The sintering and electrical properties of the hydrothermal PSZT powders obtained by substituting 4, 6 and 8 mol% Sr for Pb in PZT lattice structure were investigated. The lattice constant and particle size decreased in proportion to a quantity of Sr. The sintering properties of PSZT powders showed 7.754 g/cm 3 of sintered density and 4 μm of grain size at sintering temperature of 1250 o C. Curie temperature lowered gradually from 363.6 o C to 319.2 o C and relative dielectric constants increased rapidly by a quantity of Sr. In comparison to PZT, moreover, the quality factor of PSZT was increased more than three times with increase of Sr mole ratio, and piezoelectric constant (d31 and g31) was decreased. It was found that dielectric loss of PSZT was decreased by 0.574% which was half of PZT. The sintering and electrical properties of the hydrothermal PSZT powders obtained by substituting 4, 6 and 8 mol% Sr for Pb in PZT lattice structure were investigated. The lattice constant and particle size decreased in proportion to a quantity of Sr. The sintering properties of PSZT powders showed 7.754 g/cm 3 of sintered density and 4 μm of grain size at sintering temperature of 1250 o C. Curie temperature lowered gradually from 363.6 o C to 319.2 o C and relative dielectric constants increased rapidly by a quantity of Sr. In comparison to PZT, moreover, the quality factor of PSZT was increased more than three times with increase of Sr mole ratio, and piezoelectric constant (d31 and g31) was decreased. It was found that dielectric loss of PSZT was decreased by 0.574% which was half of PZT.

Sol - Gel 법에 의한 Mullite ( 2SiO2 . 3Al2O3 ) 분말제조

양범석,원창환,이정원 대한금속재료학회 1994 대한금속재료학회 학술대회 개요집 Vol.1994 No.0

저산소 상태로 유도된 백서 심근세포 배양에서 Minocycline의 심근보호 효과

양범석,박혜진,김홍태,이종원,이동석,노은석,정혜리,김우택 대한소아과학회 2004 小兒科 Vol.47 No.6

수열합성법으로 제조된 PZT 분말의 특성에 미치는 광화제 농도와 출바룰질의 영향

양범석,윤기석,원창환,박영철 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.11

The effect of reaction parameters in the characteristic of Pb(Zr0.52Ti0.48)O3 powders by hydrothermal process was investigated in this study. In the preparation of PZT, the types of starting material and concentration of mineralizer on phase fraction and morphology was investigated respectively. Regardless the types of Pb precursor, PZT was able to synthesize ranging from 7 to 20 on KOH concentration and from 13.01 to 13.55 on pH of solution. The particle size of the PZT powders can be controlled by the mineralizer concentration and various types of precursor. 수열합성법에 의해 제조된 PZT의 특성에 미치는 반응변수의 영향을 조사하였다. PZT의 제조에 있어 출발물질의 종류와 광화제의 농도가 상분율 및 입자크기에 미치는 영향을 각각 조사하였다. 출발물질의 종류에 관계없이 단일상 PZT의 제조가 가능한 제조조건은 광화제의 몰비 7~20몰의 범위이고 이때의 pH는 13.01~13.55 이었으며, PZT분말의 입자크기는 광화제 농도와 출발물질의 종류를 달리하여 제어가 가능하였다.

人的資源會計에 關한 一般的 考察

揚範錫 숭전대학교 1983 崇營論集 Vol.2 No.1