• Analytical Science and Technology
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• v.7 no.3
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• pp.361-369
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• 1994

Voltammetric behavior of some light lanthanide ions($La^{3+}$, $Pr^{3+}$, $Nd^{3+}$, $Sm^{3+}$ and $Eu^{3+}$) in acetonitrile(AN) and dimethylformamide(DMF) has been investigated by direct current, differential pulse polarography and cyclic voltammetry. The reduction of $La^{3+}$, $Pr^{3+}$ and $Nd^{3+}$ in 0.1M TEAP proceeded directly to the metallic state through three-electron charge transfer of irreversible process where as $Sm^{3+}$ and $Eu^{3+}$ proceeded by charge transfer of two steps. As the results of the cyclic voltammetric investigation, the first step reduction of $Sm^{3+}$ and $Eu^{3+}$ were a quasireversible reaction, the second step reductions were an irreversible reaction. The cathodic peak currents of the differential pulse polarogram showed adsorptive properties at lower sweep rates and high concentrations of these metal ions. The peak potenital was shifted to a negative petential and the peak current decreased with the increase of percentage of water in AN. On the other hand, the peak potential was shifted to a positive potential and the peak current decreased with an increased percentage of water in DMF.

• Analytical Science and Technology
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• v.7 no.3
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• pp.339-347
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• 1994

A multicolumn system consisted of two valve(10-port and 6-port valve)-three column (28% DC 200, SP 1700 and Chromosorb 102 column) was developed. Nine natural gas components composed of $N_2$, $CH_4$, $CO_2$, $C_2H_6$, $C_3H_8$, $i-C_4H_{10}$, $n-C_4H_{10}$, $i-C_5H_{12}$ 및 $n-C_5H_{12}$ completed all the baseline separation within 18 minutes. The accuracy and the precision of this system was tested. The retention times and the peak areas were determined with a repeatability between 0.02 and 0.16%, and less than 1%, respectively. Calibration curves for natural-gas components were plotted by the partial pressure injection method of pure gases, and good linear relationships for each component were presented. By using these calibration curves the accuracy of the multicolumn system compaired with that of the single column system for a certified standard gas of natural gas. As a result, relative error in the single and the multicolumn system was less than 0.5% and 0.04%, respectively. The result of application of this system in the analysis of importing LNG composition showed that the heating values calculated by the multicolum system were estimated lower compared with those calculated by the single column system and consequently, the importing price of LNG was able to be cut down.

• Analytical Science and Technology
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• v.23 no.1
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• pp.68-73
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• 2010

In order to develop the square wave voltammetric method determining cimetidine in an ampoule for injection, $5.00{\times}10^{-4}\;M$ cimetidine HCl solutions prepared with phosphate buffers of various pH values (3.01~8.97) were investigated by SWV. The well defined single peak due to the electrochemical reduction of -C=N-C$\equiv$N- in the structure of cimetidine moved towards the cathodic direction by -0.051V/pH as the pH values were increased indicating the involvement of hydrogen in its reduction. The calibration curves of cimetidine HCl in the concentration range between $1.00{\times}10^{-5}\;M$ and $5.00{\times}10^{-3}\;M$ prepared using three phosphate buffers yielded the slopes of 127,407nA/M (pH 3.01), 115,125nA/M (pH 5.00) and 111,287nA/M(pH 7.00) with excellent linearities of $R^2{\geqq}0.9997$. When one ampoule of Tagma Inj.$^{(R)}$ was analyzed by standard addition method by SWV, the within-day precision study (n=4) on the day of sample preparation resulted in the contents of cimetidine as $203{\pm}3.8\;mg$ (102% of the specified contents, RSD of 1.9%) and the inter-day precision (n=4) through 5 days was reasonable as 1.3% of RSD.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.118-123
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• 2017

This study was conducted to determine the antioxidant activities of ethanol and water extracts of Sargassum hemiphyllum. Antioxidant activities were evaluated by assessing total phenolic contents, 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, chelating effect, reducing power, and using the rancimat method. Total phenolic contents in the ethanol and water extracts were 17.91 and 13.44 mg gallic acid equivalents/g, respectively. Ethanol extract showed higher DPPH radical scavenging activity than water extract and similar activity to that of BHT. The reducing power of ethanol and water extracts increased in a concentration-dependent manner. Particularly, ethanol extract was more effective than water extract. Water extract showed a higher chelating effect compared to ethanol extract. The antioxidant index measured by rancimat was lower than those in BHT, but the ethanol extract showed a higher value than the water extract. The ethanol extract showed higher antioxidant activity than the water extract, except for the chelating effect. These results suggest that the ethanol extract of Sargassum hemiphyllum has more potent antioxidant activity and may be used as a source of natural antioxidants.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.12-20
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• 2015

After the great King Munmu constructed Donggung-palace and Wolji-pond in 674, original landscape could not be estimated due to lack of related materials for some 1,250 years until it was surveyed in 1922. Accordingly, the study, to estimate changes of Wolji-pond landscape more accurately, analyzed the study of Hara(1932) and pictures in the Japanese ruling period etc. - these had not been studied so far. The study results are as follows. As a result of comparing survey maps of 1922 and one of 1975, it was found that during 53 years, whole area excluding island showed eroded part by 2~4m, severely, there was mounding area which was lowered by 10m. And it was identified through survey map of 1922 and pictures of the 1950's that inside southern shore protection of the No. 1 construction site were many landscape-stones(景石) which can make imagine a hill; here was water path. Trace of such path etc. remained just before excavation. 2) The construction site No. 3 and 5 in peak shape were higher than construction site No. 1, 2, and 4. Accordingly, there is high possibility that construction stood on high stylobate. So it is wrong that construction site No. 3 and 5 are restored in same height as other construction sites. Comprehensive restoration basic plan made in 2012 was also wrong. As a result of estimating changes of landscape through pictures before excavation of Wolji-pond, the author could identify changes of landscape in mound area and pumice stones which showed much changes in drawing. The study has limit due to lack of space. But if more pictures can be analyzed, it could further help for estimating original landscape of Wolji-pond.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.733-738
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• 2013

This study investigated the inhibitory effect of high hydrostatic pressure (HHP) treatments on histamine production in mackerel Scomber japonicus. Changes in viable cell counts, histamine contents, pH and VBN of mackerel fillet (stored at $4^{\circ}C$ for 25 days) were examined under HPP (200, 300, and 400 MPa). HPP treatments reduced viable cell counts by 2-3 log cycles during storage. Viable cells of mackerels treated with 400 MPa did not appear for 5 days. Histamine production was nearly suppressed by 300 and 400 MPa HPP treatments after 25 days. Furthermore, mackerels treated with HPP showed significantly lower VBN values compared with the control. Additionally, pH values were not affected by the treatments during storage periods. These results suggest that HPP treatment decreased histamine contents in mackerel muscles. Based on our results, HPP treatment may reduce scombroid fish poisoning by decreasing histamine production in mackerel during $4^{\circ}C$ storage.

• The Microorganisms and Industry
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• v.12 no.2
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• pp.2-13
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• 1986

Agrobacterium tumefaciens의 연구는 유전공학 시대를 맞이하여 많은 연구자들의 커다란 주목을 끌고있다. 식물세포내에 외부 유전자를 도입시키는, 확실히 믿을 수 있는 vector로 등장된 때문이다. 원래 이세균은 식물 줄기나 뿌리에 암종을 유발시키므로서 암발성 원인 구명 연구로 흥미를 끌게 되었다. 연구결과는 암발생 예방및 치료에 목적을 둠은 덩연할 것이다. 많은 약제가 시험되었으나 별로 진전을 보지 못하던중 비 원인성인 Agrobacterium radiobacter, strain 84에 의한 생물학적 방제의 성공으로 유일한 방제법을 갖게되었다. 뒤이어 암종발생 기작도 밝혀졌다. Agrobacterium의 세계는 온통 유전공학 기술로 채워져 있다. 암종발생에서 방제원리에 이르기까지 수없이 먼 옛날부터 이미 익혀오던 DNA 조작기술이었던가\ulcorner 암종을 유발시키는 agrocin84 plasmid를 갖는 비병원성 Agrobacterium을 찾아 생물학적 방제법을 확립하였다. 그후 병원성 Agrobacterium은 이에 대하여 어떻게 살아남을 것인가\ulcorner 실로 놀라운 일이라 아니할 수 있을까\ulcorner 이 병원성 Agrobacterium은 비 병원성 Agrobacterium 속에 있는 agrocin 84 plasmid을 탈취하여 자신이 agrocin84를 생성분비하며 암종 유발을 계소하여 간다. 아니면 비병원성 Agrobacterium이 병원성 Agrobacterium에게 agrocin 84 plasmid를 넘겨주었을까\ulcorner 왜 넘겨주었을까\ulcorner 공존을 위하여서일까\ulcorner 우리의 유전공학 기술은 이것을 막아줄수 있을까\ulcorner 생물학적 방제의 재성공을 위하여 논제의 연구는 왜 필요했던가\ulcorner 그 전후를 여기에 서술해 본다.닭이며 또한 제한된 지면에서 충분히 고찰하기는 어렵다. 우리나라에서 자주 거론되는 백신 및 종류에 국한하여 그 문제점과 앞으로의 전망을 고찰해 보기로 한다.ocking electrode를 제작하여 복합고분자 전해질과의 계면저항을 측정하였다.nm (1.2921eV)는 acceptor-bound exciton 인 I1(AO,X) 이고, 964.6nm(1.2853eV)는 donor-acceptor pair(DAP) 발광, 1341.9nm (0.9239eV)는 self activated(SA)에 기인하는 광발광 봉우리로 고찰되었다.가 높을수록 방출전류가 시간에 따라 급격히 감소하였다. 각 duty비에서 방출전류의 양이 1/2로 감소하는 시점을 에미터의 수명으로 볼 때 duty비 대 에미터 수명관계를 구해 높은 duty비에서 전계방출을 시킴으로써 실제의 구동조건인 낮은 duty비에서의 수명을 단시간에 예측할 수 있었다. 단속적으로 일어난 것으로 생각된다.리 폐 관류는 정맥주입 방법에 비해 고농도의 cisplatin 투여로 인한 다른 장기에서의 농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회로의 복귀가 빠르며, 고위험군에 적용할 수 있고, 무엇보다도 미용상의 이점이 크다는 면에서 자연기흉에 대해 유용한 치료방법임에는

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.636-643
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• 1999

Green-emission intensity of a $Zn_{2-x}Mn_xSiO_4$ phosphor, which is a potential candidate as a green component in PDP device, significantly increases provided that the compound is additionally heat treated at 900$^{\circ}C$ after solid state reaction at 1300$^{\circ}C$. In order to verify origin of such an intensity enhancement after the additional heat treatment in association with the electronic and local structural change at around Mn ions, the Mn K-edge X-ray absorption spectra were recorded. From the analyses of the preedge peak corresponding to $1s{\rightarrow}3d$ bound state transition and XANES spectrum, it is known that most Mn ions are in +2 oxidation state and substitute Zn ion site regardless of the thermal treatment. In addition, EXAFS analyses revealed that Mn ions formed $MnO_4$ tetrahedra with the Mn-O bond length shortened by 0.01${\AA}$ and with reduced Debye-Waller factor in the thermally treated sample.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.202-209
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• 2002

The stochiometric mix of evaporating materials for the $CuInSe_2$single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CuInSe_2$compound crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $620^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuInSe_2$single crystal thin films measured from Hall effect by van der Pauw method. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $CuInSe_2$single crystal thin film, we have found that the values of spin orbit splitting $\Delta$So and the crystal field splitting $\Delta$Cr. From the photoluminescence measurement on $CuInSe_2$single crystal thin film, we observed free exciton ($E_x$) existing only high quality crystal and neutral bound exciton ($A^{\circ}$, X) having very strong peak intensity. Then, the full-width-at-half-maximum (FWHM) and binding energy of neutral donor bound exciton were 7 meV and 5.9 meV, respectivity. By haynes rule, an activation energy of impurity was 59 meV.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.969-974
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• 2011

This study was performed to investigate the inhibitory activity of Ecklonia cava (EC) against lipase and the stability of this activity under various heat and pH conditions. As a result, EC ethanol extract showed lipase inhibitory activity of 59, 34 and 19% at concentrations of 5, 2.5 and 1 mg/mL, whereas the water extract showed low inhibitory activity at all concentrations compared to that of the ethanol extracts. In a heat and pH stability test, the inhibitory activity of the EC ethanol extract increased with heat treatment at $121^{\circ}C$ for 15 min compared with the control and was stable in the pH range of 2~10. Therefore, the EC ethanol extract could be useful as a natural anti-obesity agent.