• 한국미생물·생명공학회지
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• 제20권2호
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• pp.178-182
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• 1992

Cephalosporium acremonium CSA-2.8A3 변이주로 부터 생성된 cephaloporin C를 정제하여 산업적 이용을 위해 ultrafiltration으로 균체를 제거하고 수종의 수지공정을 통하여 소디움염 형태의 cephalosporin C를 정제하였으며 역삼투막에 의한 농축과 분무건조를 행하였다. WA-30, HO-20, XAD-2000, SK-1B column chromatography를 통해 90% 이상의 높은 수율과 순도를 얻을 수 있었고, 특히 상기 수지들을 직렬로 연결하여 사용합으로써 수율은 96%까지 올릴 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.43-48
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• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzaolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3∼4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.75-80
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• 2003

The structures and complexation energies of penta-O-alkylated 1b and penta-O-tert-butyl ester 1e of p-tert-butylcalix[5]arene and their simplified structures (2b and 2e) toward a series of alkyl ammonium guests have been calculated by a semi-empirical AM1 method. For AM1 calculations, complexation efficiencies of the simplified host 2e are very similar to the values of host 1e. The complexes of simplified host 2e with alkyl ammonium ions also have been optimized by ab initio HF/6-31G method. The calculated complexation efficiencies for 2e by ab initio method have been found to be bigger in magnitude than the values obtained by AM1 calculations for linear alkyl ammonium guests. Calculation results show that all of the calix[5]aryl derivatives investigated in this study have much better complexation ability toward ammonium cation without alkyl group compared with other alkyl ammonium guests. Ab initio calculations also well duplicate the molecular discriminating behaviors of calix[5]arene derivative 2e between butyl ammonium ions: $n-BuNH_3^+\;>\;iso-BuNH_3^+\;>\;sec-BuNH_3^+\;>\;tert-BuNH_3^+$.

• KSBB Journal
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• 제13권4호
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• pp.383-390
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• 1998

Bacillus subtilis DT134 was resistant to 50-fold higher concentration of cadmium ions (Cd2+) than cadmium-sensitive B. subtilis BD224 in Luria Broth (LB) medium. Minimal inhibition concentration test in LB agar plates also showed similar results. The elevated cadmium resistance of B. subtilis DT134 strongly suggested a possible existence of cadmium resistance gene in it. Southern blot with Staphylococcus aureus cadA gene fragment (757 bp NlaIV-XmnI cadA DNA fragment) as probe was carried out to test the existence and similarity of the gene. In high stringency condition, there was no detectable signal, but in low stringency, a strong signal specific to the cadA probe could be detected. These results strongly suggested that there was some similarity between total DNA of B. subtilis DT134 and S. aureus pl258 in terms of cadmium resistance gene and the resistance mechanism might be an efflux mechanism. The subsequent efflux experiment showed that the cadmium resistance mechanism of B. subtilis DT134 was also due to the efflux of cadmium.

• 한국결정성장학회지
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• 제7권1호
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• pp.143-150
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• 1997

본 연구는 수소로 희석된 $B_2H_6$를 도판트 소스 가스로 사용하여 이온 질량 주입(ion mass doping)을 하였을 때 다결정 박막의 전기적 특성과 도판트의 활성화시 방사 손상(radiation damage)의 효과에 대하여 고찰하였다. 다결정 박막에서 보론(boron)의 SIMS 분석과 컴퓨터 시뮬레이션인 TRIM92를 비교해서 가장 주입 확률이 높은 이온의 종류는 $B_2H_x\;^+$(x=1, 2, 3‥‥) 형태의 분자 이온임을 알았다. 높은 에너지의 질량 이온 주입 결과 시간에 따라 변화하는 비정질화된 층의 분율이 다결정 박막 내에 연속적인 비정질 충으로 존재하였다. 주입 이온의 질량 분리가 일어나지 않는 이온 질량 주입법(ion mass doping technique)에 의해 비정질화는 유발된다. 손상된 시편의 중간 열처리 온도 범위에서 도판트 활성화 거동과 역 열처리(reverse annealing) 효과가 관찰되었다. 이와 같은 연구의 결과 p-채널 다결정 박막 트랜지스터의 오프 스테이트(off-state) 전류는 방사 손상(radiation damage)에 의존한다.

• E2M - 전기 전자와 첨단 소재
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• 제11권11호
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• pp.9-17
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• 1998

The dependence of the ionic conductivity on the B-site ion substitution in (Li0.5La0.5)Ti1-xMxO3 (M=Sn, Zr, Mn, Ge) system has been studied. Same valence state and various electronic configuration and ionic radius of Sn4+, Zr4+, Mn4+ and Ge4+(4d10(0.69$\AA$), 4p6(0.72$\AA$), 3d10(0.54$\AA$) and 3d3(0.54$\AA$), respectively) induced the various crystallographic variaton with substitutions. So it was possibleto investigate the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic variations. We found that the conductivity increased with decreasing the radii of B-site ions or vice versa and octahedron distortion disturb the ion conduction. The reason for this reciprocal proportion of conductivity on the radius of B-site ions has been examined on the base of the interatomic bond strength change due to the cation substitutions. The results were good in agreement with the experimental results. Therefore it could be concluded that the interatomic bond strength change due to the cation substitutions may be the one of major factors influencing the lithium ion conductivity in perovskite(Li0.5La0.5) TiO3system.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1747-1751
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• 2006

The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.

• 한국식품영양과학회지
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• 제23권3호
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• pp.490-495
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• 1994

Acid phosphatase (EC3.1.3.2) from carrots was partially purified by ammonium sulfate fractionation (30%-80%), Sephacryl S-200 gel filtration, cm-Sepharose CL-6B and DEAE -Sephacel ion exchange chromatography. The optimum ph and temperature of acid phosphatase from carrots were pH 5.5 and 55$^{\circ}C$, respectively. The enzyme was most stable at ph 6.0 and relatively unstable below pH 4.0 . The activation energy of the enayme was determined to be 10.6kcal/mole. The enzyme utilized p-nitrophenyl phosphate as a substrate among tested possible substrates, whereas it hydrolyzed 5' -IMP and 5'-GMP poorly. The Michaelis -Menten constant(Km) of the enzyme with p-nitrophenyl phosphate as a substrate was identified as 0.55mM. Amongtested metal ions and inhibitors, Al+++ Zn++, Cu++ , fluoride, metavanadate and molybdate ions inhibited the enzyme activity drastically.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.539-542
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• 2003

SDS-PAGE 결과 elution pH에 따라 분리되는 band pattern은 비슷하게 2band의 양상을 보이지만, FI값을 비교하여 보았을 때 다른 pH보다 8.0에서 가장 높은 수준을 보였으므로 GFPuv/cytochrome c-552 fusion Protein의 분리 ${\cdot}$ 정제에 가장 적합한 pH를 8.0으로 정하였다.

• Rapid Communication in Photoscience
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• 제4권4호
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• pp.88-90
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• 2015

The design and development of fluorescent chemosensors have recently been intensively explored for sensitive and specific detection of environmentally and biologically relevant metal ions in aqueous solution and living cells. Herein, we report the photophysical results of rhodamine B based fluorogenic and chromogenic receptor for selective copper detection in the complete organic or mixed aqueous-organic media at neutral pH under ambient condition. The ligand exhibited the remarkable increment in the fluorescence emission and UV-visible absorption signal intensities at 587 and 547 nm, respectively, on induction of copper ion while the ligand solution remain completely silent on addition of varieties of other metal ions.