• 분석과학
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• 제7권3호
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• pp.253-260
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• 1994

Low power-low flow 유도결합 플라즈마 원자방출 분광법(ICP-AES)에서 분석적 특성에 대해 연구하였다. Low power ICP에서는 moderate power ICP보다 알짜세기는 감소하지만 바탕세기도 감소하여 알짜세기에 대한 바탕세기의 비는 오히려 증가하였다. Low power ICP에서도 작동조건에 따라 moderate power와 비슷한 검출한계를 얻을 수 있으며, 검량곡선도 $10^4{\sim}10^5$ 정도의 직선성을 가질 수 있었다. 알칼리 금속에 의한 이온화 방해영향은 시료운반기체의 사용량을 증가시킬수록 증가하지만, RF power의 변화에 대해서는 큰 차이가 없었다.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.47-50
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• 2014

Voloxidation is a process for converting $UO_2$ into $U_3O_8$ while removing some volatile products in spent fuels (SF). Various oxidative gas conditions including air and mixture of Ar and $O_2$ could be adopted for the process. The gas flows into a reactor under high temperature ($>500^{\circ}C$) and components of SF are reacted with the gas. SF is composed of various components such as actinides, lanthanides, and alkali metals. Therefore, it is of significance to understand their behavior during the reactions for process development. However, due to the limit of available experiments, phase diagram analysis should be preceded. TPP diagram is constructed with respect to temperature-pressure-pressure. It shows a stable phase depending on partial pressures of gas components as well as temperature. In this work, we investigated TPP diagrams for actinides, lanthanides and other oxides to determine stable oxide forms under different gas conditions. The results would be used to set up a material balance under a pyroprocessing scheme of SF and compare the gas conditions for the optimization of fission products removal.

• 한국환경과학회지
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• 제13권1호
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• pp.79-87
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• 2004

Esterification of soybean oil with methanol was investigated. First of all, liquid-liquid equilibriums for systems of soybean oil and methanol were measured at temperatures ranging from 40 to 65$^{\circ}C$. Profiles of conversion of soybean oil with time were determined from the glycerine content in reaction mixtures for the different kinds of catalysts, such as NaOH, CaO, Ca(OH)$_2$, MgO, Mg(OH)$_2$, and Ba(OH)$_2$. The effects of dose of catalyst, cosolvent and reaction temperature on final conversion were examined. Esterification of waste vegetable oil with methanol was investigated and compared to the case of soybean oil. Solubility of methanol in soybean oil was substantially greater than that of soybean oil in methanol. When the esterification reaction of soybean oil was catalyzed by solid catalyst, final conversion was strongly dependent on the alkalinity of the solid catalyst, and increased with the alkalinity of the metal. Hydroxides from the alkali metals were more effective than oxides. When Ca(OH)$_2$ was used for the esterification catalyst, maximum value of final conversion was measured at dose of 4％. When CHCl$_3$ as a cosolvent, was added into the reaction mixture of soybean oil which catalyzed by Ba(OH)$_2$, maximum value of final conversion was appeared at dose of 3％. When waste vegetable oil was catalyzed by NaOH and solid catalysts, high final conversion, over 90％, and fast reaction rate were obtained.

• BMB Reports
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• 제36권2호
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• pp.214-222
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• 2003

A lectin named AAL has been purified from the fruiting bodies of the edible mushroom Agrocybe aegerita. AAL consisted of two identical subunits of 15.8 kDa, its pI was about 3.8 determined by isoelectric focusing, and no carbohydrate was discerned. Being treated by pyrogultamate aminopeptidase, the blocked N-terminus of AAL was sequenced as QGVNIYNI. AAL agglutinated human and animal erythrocytes regardless of blood type or animal species. Its hemagglutinating activity was unaffected by acid or alkali treatment and demetalization or addition of divalent metals $Mg^{2+}$, $Ca^{2+}$ and $Zn^{2+}$. AAL was toxic to mice: its LD50 was 15.85 mg per kilogram body weight by intraperitoneal injection. In this study, two novel activities of AAL were proved. It showed inhibition activity to infection of tobacco mosaic virus on Nicotiana glutinosa. The result of IEF suggested that AAL attached to TMV particles. Mycelia differentiation promotion was the other interesting activity. AAL promoted the differentiation of fruit body primordia from the mycelia of Agrocybe aegerita and Auricularia polytricha. AAL antiserum was prepared and immunologically cross-reactived with several proteins from five other kinds of mushrooms. These results suggested that AAL probably was a representative of a large protein family, which plays important physiological roles in mushroom.

• 한국식품영양학회지
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• 제11권6호
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• pp.595-599
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• 1998

A batch experiment was conducted to evaluate the removal capacity of welsh onion(Allium fistulosum L.), shallot (Allium ascalonicum L.), garlic (Allium sativum L.) roots as an adsorbent for Ni and Pb in aqueous solution. One gram of the dried Allium root powder was reacted in 100ml of solution containing 10mg of each heavy metal and effects of metal concentration, pH, temperature, and size of adsorbent on the removal efficiency were evaluated. The results were as follows ; The amount of adsorption of heavy metal ions were higher with the smaller particles size of adsorbent. Garlic root was high adsorption capacity of Pb, especially. The higher concentration of heavy metal solution was, the more amount of adsorption of heavy metals was. The adsorption ratio was differed from a kind of heavy metal. As the temperature increased, the amount of adsorption of Ni and Pb by shallot and welsh onion were decreased. The amount of adsorption of Ni was high under alkali conditions but the amount of adsorption of Pb was high under neutral and acidity condition.

• 한국수산과학회지
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• 제3권2호
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• pp.120-128
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• 1970

In this study, changes in chlorophyll and carotenoid pigment in fresh and ash treated Undaria pinnetifida were determined by column chromatography. And pigment stabilizing effects of ashes were discussed. The results obtained are summarized as follows: 1. The main carotenoids of Undaria pinnetifida are fucoxanthin, violaxanthin, lutein and $\beta-carotene$. 2. In storage of fresh Undaria pinnetifida at $2-5^{\circ}C$ for 30 days, chlorophyll a decreased rapidly and mainly converted to pheophytin a. Among carotenoids, lutein was markedly lost while the others retained approximately $30\%$ after 30 days' storage. 3, By treating the sample with ashes, the loss of chlorophyll a was restrained whereas that of carotenoids seemed to be promoted. It is considered that pigment stabilization was attributed to both effect, the pH control effect by the alkalinity of ashes and the fixation of the pigment by heavy metals in ashes. The stabilizing effect of chlorophyll a differed from the kind of ashes used. Reed ashes showed better effect than others such as straw or pine ashes. 4. Since fucoxanthin is extremely sensitive to alkali the treatment of ashes with a high alkalinity resulted in rapid decrease of the pigment during storage. 5. In the analysis of ashes, reed ashes which had better effect on chlorophyll a retention than the other ashes showed the highest content of iron.

• 한국재료학회지
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• 제21권9호
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• pp.502-508
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• 2011

The goal of the present work was to investigate the development of a geopolymeric ceramic material from a mixture of mine residue, coal fly ash, blast furnace slag, and alkali activator solution by the geopolymer technique. The results showed that the higher compressive strength of geopolymeric ceramic material increased with an increase in active filler (blast furnace slag + coal fly ash) contents and with a reduction of mine residue contents. The geopolymeric ceramic had very high early age strength. The compressive strength of the geopolymeric ceramic depended on the added active filler content. The maximum compressive strength of the geopolymeric ceramic containing 20 wt.% mine residue was 141.2 MPa. The compressive strength of geopolymeric ceramic manufactured by adding mine residue was higher than that of portland cement mortar, which is 60 MPa, when cured for 28 days. SEM observation showed the possibility of having amorphous aluminosilicate gel within geopolymeric ceramic. XRD patterns indicate that the geopolymeric ceramic was composed of amorphous aluminosilicate, calcite, quartz, and muscovite. The Korea Standard Leaching Test (KSLT) was used to determine the leaching potential of the geopolymeric ceramic. The amounts of heavy metals were noticeably reduced after the solidification of mine residue with active filler.

• 한국자기학회지
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• 제15권1호
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• pp.37-41
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• 2005

70% 이사의 결정질 마그키타이트를 함유한 산화철 폐촉매를 Attritor에서 미립화하고 계면활성제 종류별로 마그네타이트 미립자를 피복하여 물에 분산하므로 수상 자성유체를 제조하였다. Attritor를 사용하여 볼 : 시료 : 물의 중량비가 최적조건인 2000 : 100 : 100에서 60시간 동안 산화철 폐촉매를 미립화하고, 여기에 계면활성제 oleic acid 20 ml를 넣고 한시간 동안 가열한 후 물에 분산하므로 자화값이 22emu/g인 수상 자성유체를 제조하였다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.553-556
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• 2007

We previously reported a 27.12 MHz inductively coupled plasma source at atmospheric pressure for atomic emission spectrometry based on polymer microchip plasma technology. For the PDMS polymer microchip plasma, molecular emission was observed, but no metallic detection was done. In this experiment, a lab-made electrothermal vaporizer (ETV) with tantalum coil was connected to the microchip plasma for aqueous sample introduction to detect metal ions. The electrode geometry of this microchip plasma was redesigned for better stability and easy monitoring of emission. The plasma was operated at an rf power of 30-70 W using argon gas at 300 mL/min. Gas kinetic temperatures between 800-3200 K were obtained by measuring OH emission band. Limits of detection of about 20 ng/mL, 96.1 ng/mL, and 1.01 μ g/mL were obtained for alkali metals, Zn, and Pb, respectively, when 10 μ L samples in 0.1% nitric acid were injected into the ETV.

• Bulletin of the Korean Chemical Society
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• 제15권8호
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• pp.663-669
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• 1994

Decay kinetics of Ga(5s), Ga(5p) and Ga(4d) atoms in Ar were studied by laser induced fluorescence technique. Theground state gallium atoms in the gas phase were generated by pulsed dc discharge of trimethyl gallium and argon mixtures. Both pulsed discharge and YAG-DYE laser system were controlled by a dual channel pulse generator and the delay time between the end of discharge and laser pulses was set 3.0-6.0 ms. The Ga(5s) and Ga(4d) atoms were generated by single photon excitation from the ground state Ga atoms and radiative lifetimes as well as the total quenching rate constants in Ar were obtained from the pressure dependence of the fluorescence decay rates. The Ga(5p) atoms were populated by a two-photon excitation method and the cascade fluorescence from Ga(5s) atoms were analyzed to extract quenching rate constant of Ga(5p) atoms by Ar in addition to radiative lifetimes of Ga(5p) state. The magnitudes of the quenching rate constants by Ar for the low-lying excited states of Ga atoms are 1.6-3$ {\times}10^{-11}cm^3$ molecul$e^{-1}s^{-1}$, which are much larger than those for alkali, alkaline earth and Group 12 metals. Based on the measured rate constants, kinetic simulations were done to assign state-to-state rate constants.