• 한국산학기술학회논문지
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• 제7권3호
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• pp.332-337
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• 2006

기판전면에 패턴 없이 15 nm Co/15 nm Ni/70 nm polysilicon/200 nm $SiO_2$/Si(100) 구조로 적층된 구조로부터 급속열처리기 (rapid thermal annealer : RTA)를 이용하여 40초간 700, 900, $1000^{\circ}C$의 실리사이드화 온도를 변화시키면서 CoNi 복합실리사이드를 형성하였다. 완성된 두께 100 nm 정도의 CoNi 복합실리사이드층으로 배선층을 만든다고 상정하여, 이중 집속이온빔(dual beam focused ion beam : FIB)을 써서 30 kV에서 표면전류를 $1{\sim}100$ pA 범위에서 조절하면서 나노급 선폭제작의 가능성을 확인하였다. 각 온도별 복합실리사이드에 동일한 이온빔 조건으로 $100{\mu}m$ 길이의 패턴을 만들고, 이온빔으로 양 끝단에 트렌치를 만들어 FE-SEM으로 각 조건에서의 선폭, 두께, 최종 에칭형상을 확인하였다. 기존 형상변형이 많아서 나노급 선폭 구현이 불리한 폴리사이드 공정에 비해서, 최초로 새로운 저저항 복합실리사이드에 대해서 100 nm 이하의 나노급 피치를 가진 선폭 제작이 $30kV{\sim}30pA$ 범위에서 가능하였다.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.639-644
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• 1998

Extracellular serine proteases were isolated from a soil bacterium, alkalophilic coryneform bacterium TU-19, which have been grown in a liquid medium optimized at 3$0^{\circ}C$ and pH 10.0. Three different sizes, 120 kDa (protease I), 80 kDa (protease II), and 45 kDa (protease III), of serine pro teases were purified using Sephadex G-150 and QAE-Sephadex chromatography (Kang et al. 1995. Agric. Chem Biotech. 38: 534-540). SDS-PAGE showed that the 120 kDa protease was degraded into the 80 kDa protease in 20 mM Tris-HCI (pH 8.0) buffer solution. This degradation was enhanced in the presence of 0.5 M NaCl and 5 mM EDTA, but was inhibited in the presence of 5 mM $CaCl_2$. These results indicated that the $Ca^{2＋}$ ion seems to stabilize the 120 kDa protease like other proteases derived from Bacillus species. The $NH_2$-terminal amino acid sequences of the 10 residues of both proteases were completely identical: Met-Asn-Thr-Gln-Asn-Ser-Phe-Leu-Ile-Lys. In contrast to this, the 80 kDa protease has 1.5 times higher specific activity than the 120 kDa protease does (Kang et al. 1995. Agric. Chern. Biotech. 38: 534-540). Therefore the C-terminal of the 120 kDa protease seems to be autolyzed to the 80 kDa protease but this autolysis did not decrease the protease activity. Optimum pH and temperature of both 80 kDa and 120 kDa proteases were pH 10.5 and $45^{\circ}C$, respectively, and pH and thermal stability were almost identical. Several divalent ions except the $Fe^{2＋}$ ion showed similar effects on activities of both proteases, which are similarly resistant to three different detergents.

• 한국미생물·생명공학회지
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• 제31권3호
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• pp.224-229
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• 2003

경기도 일대의 가금류 공장부근 토양로부터 keratinolytic protease 생산성이 우수한 균주 KP-364를 선별하여 본 효소를 정제하고 일반적인 특성을 조사하였다. 본 효소는 ulkafiltration, ammonium sulfate fiactionation, DEAE-cellulose ion-exchange chromatography, Sephadex G-150 gel filtration 등을 통하여 정제되었으며 회수율은 25.2%이었다 SDS-PAGE와 gel filtration으로. 단일성과 분자량을 추정한 결과 전기영동 상에 단일 band를 나타내었으며 분자량은 약 36,000 dalton이였으며 1개의 subunit로_구성되어 있었다. 효소반응의 최적조건을 검토한 결과 최적 pH는 6.5, pH 3.0에서 10.0까지 90%이상의 활성을 나타냈으며 반응 최적 온도는 $37^{\circ}C$이였고 $60^{\circ}C$에서 1시간동안 80%이상의 활성을 유지하였다. 정제된 효소의 활성은$ FeSo_4$, KCI, $Li_2$$SO_4$를 첨가하였을 때 증가하였으며 $Ag_2$$SO_4$, $CuCl_2$, $HgCl_2$에 의해 저해되었다. 또한 EDTA, EGTA에 의해 저해되는 것으로 보아 metalloprotease의 일종이라고 판단되며 $Li^{ +}$를 cofactor로 함유하고 있는 것으로 조사되었다.

• Journal of Pharmaceutical Investigation
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• 제1권1호
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• pp.101-108
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• 1971

The stability and toxicity test for p.p'-DDT, DDVP and dipterex that put to used sample in this study effects is follows A. about p.p'-DDT (1) In elevating the stability of p.p'-DDT, best stabilizing solvent was benzene. (2) The stability-agent has no difficulty as long as it not contain metal ion for instance $Z_n^{2+}$,$C_r^{3+}$,$Al^{3+}$,and $Fe^{2+or3+}$ but in case of contain $F_e^{3+}$, the combination of salicylaminoguanidine is best effective. (3) Using this product for water-suspension, We must use span 40 for stability agent and adding it at the same time. (4) We must use container which does not week alkali and metal ion but it is to preserved in tight light-resistant container. (5) The stopper of container is adapted with above-mentioned condition of container, but it is better not to use metal material. (6) This product needs opening ventilation more than 30 minutes after diffusion or spray and in the room we remove cause of remained poison by cleaning the bottom. B. about DDVP and Dipterex (1) Benzene or toluene in best solvent to preserve stability of DDVP and Dipterex. (2) Span 40 is superior for stability agent of this product and second is span 80. (3) The pH of solution is very stable in pH 5-6 and comparative stable in alkali more than p,p'-DDT. (4) Container is to preserved in tight, lightresistant container and especially be careful of outflow and inflow of water. (5) Because this product is centeral stimulant poison, we must pay attention to prevent cause of contact diadermic toxicity after use.

• Applied Biological Chemistry
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• 제33권1호
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• pp.73-78
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• 1990

한국산 토마토로부터 endo-polygalacturonase를 gel filtration과 이온교환크로마토그라피에 의하여 약 24배 정제할 수 있었고, 최대 효소활성을 위한 PH는 5.0, 최적온도는 $50^{\circ}C$ 였으며 pH안정범위는 $4.0{\sim}5.0$, 열안정성은 $50^{\circ}C$에서 1시간 열처리 하였을 때 약 45 % 실활 되었다. 정제된 이 효소는 SDS-polyacrylamide gel 전기영동에 의하여 단일밴드로 확인되었으며, 그 분자량은 50,000정도였고, Km값은 $1.43{\times}10^{-1}\;mol/l이었다. 금속이온중 $Ag^+$, $Zn^{++}$이온이 효소의 활성을 촉진시켰으며, $Na^+$, $K^+$등의 이온에 의해서는 활성이 저해되었다.

• Journal of Astronomy and Space Sciences
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• 제32권2호
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• pp.145-149
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• 2015

A newly designed Tissue Equivalent Proportional Counter (TEPC) has been developed for the CubeSat mission, SIGMA (Scientific cubesat with Instruments for Global Magnetic field and rAdiation) to investigate space radiation. In order to test the performance of the TEPC, we have performed heavy ion beam experiments with the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. In space, human cells can be exposed to complex radiation sources, such as X-ray, Gamma ray, energetic electrons, protons, neutrons and heavy charged particles in a huge range of energies. These generate much a larger range of Linear Energy Transfer (LET) than on the ground and cause unexpected effects on human cells. In order to measure a large range of LET, from 0.3 to $1,000keV/{\mu}m$, we developed a compact TEPC which measures ionized particles produced by collisions between radiation sources and tissue equivalent materials in the detector. By measuring LET spectra, we can easily derive the equivalent dose from the complicated space radiation field. In this HIMAC experiment, we successfully obtained the linearity response for the TEPC with Fe 500 MeV/u and C 290 MeV/u beams and demonstrated the performance of the active radiation detector.

• Environmental Engineering Research
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• 제10권5호
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• pp.205-212
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• 2005

The study was conducted to investigate the removal of heavy metals by using Hydroxyapatite(HAp) made from waste oyster shells and wastewater with high concentration of phosphorus. The maximum calcium concentration for the production of HAp in this study was released up to 361 mg/L at pH of 3 by elution experiments. When the pH was at adjusted 6, the maximum calcium released concentration was 41 mg/L. During the elution experiment, most of the calcium was released within 60 minutes. This reaction occurred at both pH levels of 3 and 6. The result of the XRD analysis for the HAp product used in this study shows the main constituent was HAp, as well as OCP. The pH was 8.6. As the temperature increased, the main constituent did not vary, however its structure was crystallized. When the pH was maintained at 3, the removal efficiency decreased as the heavy metal concentration increased. The order of removal efficiency was as follows: $Fe^{2+}$(92%), $Pb^{2+}$(92%) > $Cu^{2+}$(20%) > $Cd^{2+}$(0%). Most of these products were dissolved and did not produce sludge in the course of heavy metals removal. As the heavy metal concentration increased at pH of 6, the removal efficiency increased. The removal efficiencies in all heavy metals were over 80%. From the analysis of the sludge after reaction with heavy metals, the HAp was detected and the OCP peak was not observed. Moreover, lead ion was observed at the peaks of lead-Apatite and lead oxidant. In the case of cadmium, copper and iron ions, hydroxide forms of each ion were also detected.

• 상하수도학회지
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• 제24권3호
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• pp.341-349
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• 2010

It is well known that manganese is hard to oxidize under neutral pH condition in the atmosphere while iron can be easily oxidized to insoluble iron oxide. The purpose of this study is to identify removal mechanism of manganese in the D water treatment plant where is treating bank filtered water in aeration and rapid sand filtration. Average concentration of iron and manganese in bank filtered water were 5.9 mg/L and 3.6 mg/L in 2008, respectively. However, their concentration in rapid sand filtrate were only 0.11 mg/L and 0.03 mg/L, respectively. Most of the sand was coated with black colored manganese oxide except surface layer. According to EDX analysis of sand which was collected in different depth of sand filter, the content of i ron in the upper part sand was relatively higher than that in the lower part. while manganese content increased with a depth. The presence of iron and manganese oxidizing bacteria have been identified in sand of rapid sand filtration. It is supposed that these bacteria contributed some to remove iron and manganese in rapid sand filter. In conclusion, manganese has been simultaneously removed by physicochemical reaction and biological reaction. However, it is considered that the former reaction is dominant than the latter. That is, Mn(II) ion is rapidly adsorbed on ${\gamma}$-FeOOH which is intermediate iron oxidant and then adsorbed Mn(II) ion is oxidized to insoluble manganese oxide. In addition, manganese oxidation is accelerated by autocatalytic reaction of manganese oxide. The iron and manganese oxides deposited on the surface of the sand and then are aged with coating sand surface.

• 한국세라믹학회지
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• 제48권1호
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• pp.34-39
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• 2011

Systematic study on relationship between celadon coloring and glaze component was conducted by chromaticity analysis and M$\ddot{o}$ssbauer spectroscopic analysis. The chromaticity ($L^*$, $a^*$, $b^*$ values) and M$\ddot{o}$ssbauer analysis results were correlated to the amount of $Fe_2O_3$, $TiO_2$, MnO, and $P_2O_5$, which are the essential factors influencing celadon coloring. According to chromaticity analysis, celadon glaze color belongs to GY group when the addition of $TiO_2$ was 1.4%, whereas the color belongs to BG group when the addition of $TiO_2$ was 0.1%. For the GY group, the colors change from GY to YR with the decrease of brightness as the addition of $TiO_2$, MnO, and $P_2O_5$ increases. According to M$\ddot{o}$ssbauer analysis results, as the amount of divalent iron ion increases, the $a^*$ and $b^*$ values decrease, on the other hand, $L^*$ value increases. The ratio of divalent iron ion produced in reductive sintering process is found to be 80~95% in this study, which induces the increase of $L^*$ values in celadon glaze.

• Journal of Electrochemical Science and Technology
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• 제5권1호
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• pp.32-36
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• 2014

The $0.3Li_2MnO_3{\cdot}0.7LiMn_{0.55}Ni_{0.30}Co_{0.15}O_2$ cathode material was prepared via a co-precipitation method. The vapor grown carbon fiber (VGCF) was used as a conductive material and its effects on electrochemical properties of the $0.3Li_2MnO_3{\cdot}0.7LiMn_{0.55}Ni_{0.30}Co_{0.15}O_2$ cathode material were investigated. From the XRD pattern, the typical complex layered structure was confirmed and a solid solution between $Li_2MnO_3$ and $LiMO_2$ (M = Ni, Co and Mn) was formed without any secondary phases. The VGCF was properly distributed between cathode materials and conductive sources by a FE-SEM. In voltage profiles, the electrode with VGCF showed higher discharge capacity than the pristine electrode. At a 5C rate, 146 mAh/g was obtained compared with 232 mAh/g at initial discharge in the electrode with VGCF. Furthermore, the impedance of the electrode with VGCF did not changed much around $9-10{\Omega}$ while the pristine electrode increased from 21.5${\Omega}$ to $46.3{\Omega}$ after the $30^{th}$ charge/discharge cycling.