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        검색결과 165

        141.
        2013.10 KCI 등재 서비스 종료(열람 제한)
        Na-A zeolite (Z-Cl) was synthesized from coal fly ash, which is a byproduct of coal combustion for the generation of electricity. The adsorption of Cu2+ and Zn2+ions onto Z-C1 was investigated via batch tests over a range of temperatures (303.15 to 323.15 K). The resultant experimental equilibrium data were compared to theoretical values calculated using model equations. With these results, the kinetics and equilibrium parameters of adsorption were calculated using Lagergren and Langmuir-Freundlich models. The adsorption kinetics revealed that the pseudo second-order kinetic mechanism is predominant. The maximum adsorption capacity (qmax) values were 139.0-197.9 mg Zn2+/g and 75.0-105.1 mg Cu2+/g. Calculation of the thermodynamic properties revealed that the absorption reactions for both Cu2+and Zn2+ were spontaneous and endothermic. Collectively, these results suggest that the synthesized zeolite, Z-C1, can potentially be used as an adsorbent for metal ion recovery during the treatment of industrial wastewater at high temperatures.
        142.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        The adsorption performance of cupper and zinc ions(Cu2+ and Zn2+) in aqueous solution was investigated by an adsorption process on reagent grade Na-A zeolite(Z-WK) and Na-A zeolite (Z-C1) prepared from coal fly ash. Z-C1 was synthesized by a fusion method with coal fly ash from a thermal power plant. Batch adsorption experiment with Z-C1 was employed to study the kinetics and equilibrium parameters such as initial metal ions concentration and adsorption time of the solution on the adsorption process. Adsorption rate of metal ions occurred rapidly and adsorption equilibrium reached at less than 120 minutes. The kinetics data of Cu2+ and Zn2+ ions were well fitted by a pseudo-second-order kinetics model more than a pseudo-first-order kinetics model. The equilibrium data were well fitted by a Langmuir model and this result showed Cu2+ and Zn2+ adsorption on Z-C1 would be occupied by a monolayer adsorption. The maximum adsorption capacity(qmax) by the Langmuir model was determined as Cu2+ 99.8 mg/g and Zn2+ 108.3 mg/g, respectively. It appeared that the synthetic zeolite, Z-C1, has potential application as absorbents in metal ion recovery and mining wastewater.
        144.
        2009.03 KCI 등재 서비스 종료(열람 제한)
        스테로이드 함유 표시가 없는 화장품에서 항염증 효과가 있는 글루코코티코스테로이드인 베타메타손프로피오네이트 성분이 검출되었다. 이 화장품은 외용스프레이 및 샴푸로서 주성분으로 아연피리치온을 함유하는 것으로 표기되어 있었다. 화장품에서 스테로이드 구조와 활성을 갖는 물질의 존재를 확인하기 위하여 실리카겔 박층판을 이용한 박층크로마토그래프를 사용하였으며 이 성분을 분리하기 위해 high-performance liquid chromatography (HPLC)를 이용하여 확인 및 정량을 수행하였다. 분취용 HPLC를 이용하여 스테로이드를 함유한 것으로 판단되는 분획을 모은 다음 nuclear magnetic resonance (NMR) 및 mass spectrometry (MS)를 이용하여 스테로이드 성분을 확인하였다. 스테로이드 표준물질로 베타메타손 17-프로피오네이트 및 베타메타손 21-프로피오네이트를 합성하여 사용하였고 이 표준물질과 HPLC 크로마토그램을 비교하여 스테로이드 성분의 함량을 분석하였다. 이 방법으로 아연피리치온 제제와 같은 일부 시판 화장품에서 스테로이드 성분을 확인하였고 reversed-phase high-performance liquid chromatography (RP HPLC) 상의 유지시간 비교를 통하여 스테로이드 성분을 정량한 결과 시험한 총 8종의 화장품 시료 중 2개 제품에서 0.005 ∼ 0.02 %의 베타메타손프로피오네이트가 검출되었다.
        146.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        The C3HC4 zinc RING finger proteins seem to be a family of protein-protein interactions. Little is information regarding the role of the C3HC4 zinc RING finger proteins in rice plant. We have attempted to assess their genome localization, phylogenetic relationship and expression patterns of members via in silico analysis as well as semi-quantitative RT-PCR. A total of 132 genes encoding C3HC4 zinc RING finger proteins appear to be distributed over 12 rice chromosomes, reflecting evolutionary dynamics of the rice genome, e.g. whole genome duplication and tandem duplications. A genome-wide dataset including 155 gene expression omnibus sample (GSM) plates evidenced a high degree of functional specialization of the rice C3HC4 zinc RING finger proteins, especially during developmental stages and against abiotic stresses. We have retrieved co-expression genes with each of the rice C3HC4 zinc RING finger proteins, probably providing some clues on specialized functions of individual genes. Expression patterns of 13 co-expression genes with one gene encoding C3HC4 zinc RING finger protein (Os04g51400) against salt and dehydration stresses were evaluated in crown tissues and leaf tissues, evidencing highly similar patterns among members. These findings might provide clues to shed further light on comprehensive functions of C3HC4 zinc RING finger proteins.
        147.
        2008.06 KCI 등재 서비스 종료(열람 제한)
        The germplasm of 246 rice cultivars was analysed  for iron and zinc contents using a Inductively Coupled Argon Plasma (ICP) at International Rice Research Institute (IRRI) Philippines. Iron contents ranged from 2.0 to 12.0, and zinc ranged from 10.0 to 33.0 (mg/kg), showing with the mean values of 4.3 and 22.8 (mg/kg), respectively. In genotypes tested, there was approximately a two-fold difference in iron and zinc concentrations, suggesting a genetic potential to increase these micronutrients in rice grain. A highly significant positive correlation (r2=0.503) was found between iron and zinc contents. Iron contents decreased drastically as polishing time increased, whereas zinc decreased only slightly. In the interaction between genotype and environment on iron contents, genotype (G), environment (E), and the G × E interactions accounted for 69%, 5% and 26% of the sums of squares, respectively. Indicating that genotype is would be the most significant factor for the to improve iron contents of rice in rice breeding, suggesting that therefore identifying genotypes with relatively stable performance across various environments is important as staple food crops.
        156.
        2006.12 KCI 등재 서비스 종료(열람 제한)
        The characteristics of photocatalytic degradation of tar colorants such as brilliant blue FCF(BBF) and tartrazine(TTZ) with zinc oxide suspension was studied in a batch reactor under irradiation of ultra-violet ray. Photocatalytic degradation of TTZ with ZnO was more higher than that of BBF, and was increased with dosage of ZnO below 5g, but was nearly affected with initial pH of two tar colorants aqueous solution. Ammonium persulfate was more effective oxidant than potassium bromate which slightly increased the degradation of BBF, but not increased the degradation of TTZ. The photocatalytic degradation rates of BBF and TTZ were pseudo-first order with rate constants of 0.0066, 0.0092 and 0.015min-1 for BBF, 0.042, 0.077 and 0.110min-1 for TTZ at the dosage of 1, 2 and 5g ZnO, respectively.
        159.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.
        160.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        Effects of surface conditions (temperature and roughness) of test specimens, when measuring emissive power of far-infrared ray, have been investigated using FT-IR spectrometer. Element metal zinc (Zn) was selected in this study as representative specimen of materials consisting of simple element. The zinc specimens were heated to four temperatures, i.e., 333K, 353K, .373K, and also their surface was finished with SiC abrasive papers of 100, 220, 360, 400, 600, 800, and 1000 mesh in size. The results shows that the emissive power (W/㎡) of the far-infrared ray increases with temperature for a given roughness and its relationship may be expressed by the following equations: Yη=1.0=0.142.T-0.937 for η=1.0, and Yη=10=0.016.T-1.286 for η=10. The emissive power is also known to increase with surface roughness for a given temperature. Their relationship can be represented by the following equations: YT=313K=0.234.ln(η)+3.53, at 313K, YT=353K=0.234.ln(η)+4.02 at 353K and YT=393K=0.243.ln(η)+4.62 at 393K.
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