• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.86.2-86
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• 2003

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1593-1596
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• 2012

A new enzyme immobilization method based on hydrophobic interaction between supporting material and enzyme has been successfully developed. The efficacy of the new technique has been investigated by loading a horse radish peroxidase (HRP) enzyme on the surface of conducting polymer-silica composites and by measuring the enzyme activity and leaching property of HRP loaded within polymer-silica composites. The immobilized HRP enzyme showed activity profiles similar to that of free HRP in phosphate buffer (pH 6). Above all, HRP adsorbed on the polymer-silica composites has showed excellent stability over 10 days, compared to HRP adsorbed on the pristine silica. It is thought that with appropriate optimization works, the present method would be used as a cost-effective and facile route for the immobilization of biomolecules.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.45-50
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• 1986

Separation of optical isomers of some derivatives of amino acids by reversed-phase HPLC has been accomplished by adding a chelate of an optically active amino acid to copper(Ⅱ) to the mobile phase. Cu(Ⅱ) complexes of L-proline and L-hydroxyproline in the mobile phase showed different degrees of separation. Optical isomers of DNS derivatives of amino acids are selectively separated, but those of several other derivatives are not at all. The kinds of buffer agents, the pH, and the concentrations of acetonitrile and the Cu(Ⅱ) ligand all affect the separations. The elution behavior between D and L DNS-amino acids appears to depend on the alkyl side chain of the amino acids. A chromatographic mechanism is proposed that is based on a stereospecificity of the formation of ternary complexes by the D, L-DNS-amino acids and the chiral additive associated with the stationary phase. The steric effects of the ligand exchange reactions are related with the feasibility of cis and/or trans attack of the amino acids to the binary chiral chelate retained on the stationary phase.

• 대한수의학회지
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• 제39권5호
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• pp.930-937
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• 1999

Atrial natriuretic peptide(ANP) is a hormone with potent natriuretic, diuretic and relaxing properties on vascular smooth muscle. Specific chemical modulator in response for the ANP secretion has not been found yet. Therefore, we have investigated the role of $Ca^{2+}$ responsible for the regulation of ANP induced by protein kinase C(PKC) on mechanically stretch-induced ANP secretion in the rat atria. The results obtained were as follows ; 1. ANP secretion and ANP concentration were increased to more in $Ca^{2+}$-free buffer than in the Kreb-Henseleit buffer on mechanically stretch-induced ANP secretion(p < 0.05), but extracellular fluid translocation(ECF) was not significant. Phorbol 12-myristate 13-acetate(PMA, $10^{-7}M$) induced ANP secretion and ANP concentration in $Ca^{2+}$-free buffer shown to more accentuate on mechanically stretch-induced ANP secretion than in the $Ca^{2+}$-free buffer(p < 0.05), but ECF translocation was not significant. 2. In the presence of ryanodine($3{\times}10^{-6}M$), PMA($10^{-7}M$) induced ANP secretion and ANP concentration in the Kreb-Henseleit buffer were shown to more increase on mechanically stretch-induced ANP secretion than in the ryanodine($3{\times}10^{-6}M$) with the Kreb-Henseleit buffer(p < 0.05), but ECF translocation was not significant. 3. In the presence of ryanodine($3{\times}10^{-6}M$), PMA($10^{-7}M$) induced ANP secretion and ANP concentration in the $Ca^{2+}$-free buffer was shown to more increase on mechanically stretch-induced ANP secretion than in the ryanodine($3{\times}10^{-6}M$) with the $Ca^{2+}$-free buffer on mechanically induced ANP secretion(p < 0.05), but ECF translocation was not significant. The results suggest that PKC-induced ANP secretion may not be related to the change of $Ca^{2+}$ on mechanically induced ANP secretion in the rat atria.

• 한국토양비료학회지
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• 제21권3호
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• pp.280-288
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• 1988

강원도(江原道) 지역(地域)의 답토양(畓土壤)이 널리 분포(分布)되어 있는 석회암지대(石灰岩地帶), 하성충적충지대(河成沖積層地帶), 현무암지대(玄武岩地帶) 토양(土壤)을 대상(對象)으로 하여 석회요구량(石灰要求量) 결정방법(決定方法)간의 차이(差異)를 실험적(實驗的)으로 비교(比較), 검토(檢討)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 석회요구량(石灰要求量)을 결정(決定)하는 7가지 방법(方法)($CaCO_3$ incubation method, $BaCl_2$-TEA method, SMP-single buffer method, Double buffer method, Adams and Evans method, SMP-double buffer method, O. R. D. method)을 비교(比較)한 결과(結果) 방법(方法)간에 큰 차이(差異)가 있었다. 2. $CaCO_3$ incubation method를 기준(基準)으로 할 때 석회요구량(石灰要求量)은 $BaCl_2-TEA$ method가 가장 높았고, O.R.D. method 가 가장 적었으며, SMP-double buffer method가 강원도(江原道) 토양(土壤)에 비교적(比較的) 적합(適合)할 것으로 평가(評價)되었다. 3. 치환성(置換性) Al 함량(含量)의 100% 당량(當量)에 해당(該當)하는 $CaCO_3$를 가(加)하고 incubation한 경우 약(約) 70%의 중화율(中和率)을 나타냈다. 4. 활성(活性) Al 함량(含量)의 100% 당량(當量)에 해당(該當)하는 $CaCO_3$를 가(加)하고 incubation한 경우에는 약(約) 30%의 중화율(中和率)을 나타냈다. 5. 치환성(置換性) Al 및 활성(活性) Al 함량(含量)을 기준(基準)으로 한 석회요구량(石灰要求量)은 $CaCO_3$ incubation method에 비(比)해 적은 값을 나타냈다.

• 멤브레인
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• 제18권4호
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• pp.306-316
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• 2008

전기방사법을 이용하여 제조된 pelyestersulfone (PES)-bovin albumin serum (BSA) 친화막에 대하여 L-tryptophan에 대한 흡착특성을 연구하였다. FESEM과 Image Analyzer를 이용하여 방사조건에 따른 섬유의 직경분포를 비교분석 함으로써 섬유의 직경을 조절할 수 있음을 알았다. 또한, 2,2,3,4,4,4-Hexafluoro-1-butanol (HFB)와 BSA의 함량증가에 따른 미세섬유 발생빈도가 높아져서 Darcy 투과도, 기계적 물성, 발수성이 증가한다는 것을 알았다. L-tryptophan의 용출량은 tris-HCl 완충용액보다 borate-DMSO 완충용액에서 높았으며, A 8022형 BSA보다 A 7906형 BSA가 높은 용출량을 보였다. 이러한 결과는 BSA의 종류에 따른 그 특성에 기인하는 것으로 A 7906형은 A 8022형보다 순도가 높고 분자량 분포가 고르며, 사용 pH 환경이 더욱 안정적이기 때문이다.

• 대한화학회지
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• 제23권3호
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• pp.175-179
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• 1979

Phthalimido기와 2,2,2-trichloroethyl기는 acetic acid와 같은 산성용매에서 zine dust에 의하여 각각 3-hydroxyphthalimidino기로 환원 되거나 혹은 환원분해된다. 그러나 THF-pH 4.5 buffer 혼합용매를 사용하므로써, free carboxylic acid가 존재하지 않는 경우, phthalimido는 환원시키지 않고 2,2,2-trichloroethyl기만을 선택적으로 환원분해시킬 수 있음을 발견하였다. 따라서 $2,2,2-trichloroethyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-{\beta}-D-glucopyranose$ (1)를 THF-pH 4.5 butter 혼합용매에서 zinc dust와 반응시키면, 2,2,2-trichloroethyl 기만이 선택적으로 환원분해된 $3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-{\beta}-D-glucopyranose$ (5)를 좋은 수득율로 얻을 수 있었다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.56-60
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• 2000

Cube texture를 갖는 Ni기판위에 MOCVD(Metal Chemical Vapor Deposition)를 이용하여 NiO, CeO$_2$, YBCO 박막을 제조하였다. NiO(200)와 CeO$_2$(200) buffer layer는 450${\sim}$470$^{\circ}$C에서 10분간 MOCVD방법으로 (100)<001>Ni 기판위에 직접 증착하였다. 제조된 NiO, CeO$_2$ buffer layer는 조직이 치밀하며 표면의 상태가 매우 좋으며 Ni기판 위에 epitaxial하게 성장하였다. NiO는 Ni기판과 NiO<100>//Ni<100>의 방위관계를 가지고 성장하였으며, CeO$_2$는 증착조건에 따라 CeO$_2$ <100>//Ni<100> 및 CeO$_2$ <110>//Ni<100> 의 방위관계를 가지고 성장하였다. 증착된 NiO막과 CeO$_2$막에서 균열은 발생하지 않았다. MOCVD법으로 표면에 biaxial texture를 갖는 ceramic buffer를 증착시킨 NiO/Ni및 CeO$_2$/Ni 기판위에 YBCO박막을 MOCVD법으로 제조하였다. YBCO막은 기판온도 800$^{\circ}$C,증착압력 10torr, 산소분압을 0.7torr로 하여 10분간 행하였다. 공급원료의 조성에 따라 YBCO의 막의 texture와 형성되는 상이 변화되었다. NiO/Ni및 CeO$_2$/Ni 기판 위에 증착된 YBCO막은 c축 배향성을 가지고 성장하였으며, -scan 및 ${\varphi}$ -scan으로 측정한 (500)면의 in-plane과 (110)면의 out-of-plane의 FWHM(Full Width Half Maximum)값은 각각 10$^{\circ}$ 미만으로 우수하였다.

• Progress in Superconductivity
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• 제11권2호
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• pp.123-127
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• 2010

The properties of buffer layer for thermal and chemical stability in coated conductor is a very important issue. $CeO_2$ has desirable thermal and chemical stability as well as good lattice match. In this study, $CeO_2$ was deposited by electron beam deposition. The MgO(001) single crystal and LMO buffered IBAD substrate(LMO/IBAD-MgO/$Y_2O_3/Al_2O_3$/Hastelloy) were used as substrates, which have $\Delta\phi$ values of ${\sim}8.9^{\circ}$. The epitaxial $CeO_2$ films was deposited with high deposition rate of $12{\sim}16\;{\AA}/sec$. During deposition, the change of oxygen partial pressure(${\rho}O_2$) does not cause change in c-axis texture. In case of $CeO_2$ on MgO single crystal, the substrate temperature was optimized at $750^{\circ}C$ with superior $\Delta\phi$ and $\Delta\omega$ value. Otherwise, In case of LMO buffered IBAD substrate, It was optimized at $650^{\circ}C$ with increasing its deposition thickness of $CeO_2$, which was finally obtained with best $\Delta\phi$ value of $5.5^{\circ}$, $\Delta\omega$ value of $2^{\circ}$ and Ra value of 2.2 nm.

• 센서학회지
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• 제16권6호
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• pp.457-461
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on $SiO_{2}$ and AlN substrates, respectively. The crystallinity and the bonding structure of poly 3C-SiC grown on each substrate were investigated according to various growth temperatures. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD and FT-IR by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_{2}$ and AlN were not different. However, their electron mobilities were $7.65{\;}cm^{2}/V.s$ and $14.8{\;}cm^{2}/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_{2}$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.