• 대한화학회지
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• 제42권5호
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• pp.539-548
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• 1998

여러자리 산소-질소계 리간드들은 시프염기 리간드인 Bis(salicylidene)-ethylendiamine(BSED), Bis(salicylidene)-propylenediamine(BSPD), Bis(salicylidene)-diethylenetriamine(BSDT), Bis(salicylidene)-triethylenetetraamine(BSTT) 및 Bis(salicylidene)-tetraethylenepentaamine(BSTP)의 이민기를 수소환원장치에서 백금촉매를 이용하여 네자리 리간드인 N,N'-bis(2-hydroxybenzyl)-ethylenediamine(BHED)과 N,N'-bis(2-hydroxybenzyl)-propylenediamine(BHPD), 다섯자리 N,N'-bis(2-hydroxybenzyl)-diethylenetriamine(BHDT), 여섯자리 N,N'-bis(2-hydroxybenzyl)-triethylenetriamine(BHTT), 일곱자리 N,N'-bis(2-hydroxybenzyl)-tetraethylenepentaamine(BHTP) 리간드들을 합성하였다. 리간드들의 양성자 해리상수와 전이금속(Ⅱ)과 착물의 안정도상수는 전위차 적정법으로 측정하였다. 리간드별 전이금속(Ⅱ)이온에 대한 착물 안정도상수값$(logK_{ML})$의 크기는 BHED아연(Ⅱ)의 순서로 이 결과는 Irving-Williams 서열과 잘 일치하여 증가하였다.

• 한국세라믹학회지
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• 제41권9호
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• pp.670-676
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• 2004

플라즈마 디스플레이(Plasma Display Panel)의 도전성 전극 성형에 필요한 잉크젯용 은 나노 졸을 합성하고자, 액상 환원법에 의해 고농도의 은 나노 졸의 입자크기 및 입도분포와 분산성을 제어하였다 이를 위하여 생성된 입자에 분산성을 부여하는 고분자 전해질의 착체형성 비율과 함께 은 나노 졸의 고농도화를 진행하였다. 합성된 졸은 XRD, 입도분포측정기, TEM을 사용하여 상분석 및 입자의 크기와 형상을 관찰하였다 그 결과 분산성이 우수하고, 약 10nm의 입자크기를 갖는 은 나노 졸인 것을 확인할 수 있었으며, 10-40wt% 범위의 고농도 은 나노 졸을 합성할 수 있었다.

• 한국세라믹학회지
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• 제43권2호
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• pp.79-84
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• 2006

We studied the microstructure and magnetic property of the pulsed DC magnetron sputtered $Zn_{\0.8}Co_{0.2}O$ film as a function of substrate temperatures. The X-ray patterns of the $Zn_{\0.8}Co_{0.2}O$ film showed a strong (002) preferential orientation at $500^{\circ}C$. The films with a crystallite size of 23-35 nm were grown in the form of nano-sized structure and this tendency was remarkable with increasing substrate temperature. The UV-visible result showed that the $Zn_{\0.8}Co_{0.2}O$ film prepared above $300^{\circ}C$ has a high optical transmittance of over $80\%$ in the visible region. The absorption bands were observed due to sp-d interchange action by $Co^{2+}$ complex ion and dd transition in the region from 500 to 700nm. The resistivity of the film was below $10^{-1}\;\Omega-cm\;above\;300^{\circ}C$. The AGM analysis results for the all films showed the magnetic hysteresis curves of ferromagnetic nature. The low electrical resistivity and room temperature ferromagnetism of ZnCoO thin films 'deposited above $300^{\circ}C$ suggested the possibility for the application to Diluted Magnetic Semiconductors (DMSs).

• Parasites, Hosts and Diseases
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• 제48권2호
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• pp.127-132
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• 2010

Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, and fumaric acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to test the potentiality of these acids to be used as diagnostic and therapeutic biomarkers. The assay was done in both hemolymph and digestive gland-gonad complex (DGG) samples in a total of 300 B. alexandrina snails. All of the studied acids in both the hemolymph and tissue samples except for the fumaric acid in hemolymph appeared to be good diagnostic biomarkers as they provide not only a good discrimination between the infected snails from the control but also between the studied stages of infection from each other. The most sensitive discriminating acid was malic acid in hemolymph samples as it showed the highest F-ratio. Using the Z-score, malic acid was found to be a good potential therapeutic biomarker in the prepatency stage, oxalic acid and acetic acid in the stage of patency, and malic acid and acetic acid at 2 weeks after patency. Quantification of carboxylic acids, using HPLC strategy, was fast, easy, and accurate in prediction of infected and uninfected snails and possibly to detect the stage of infection. It seems also useful for detection of the most suitable acids to be used as drug targets.

• 한국물환경학회지
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• 제23권3호
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• pp.319-323
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• 2007

The Advanced Oxidation Process (AOP) is being increasingly used to oxidize complex organic constituents in treated effluents from domestic wastewater treatment plants. Generally, ${NO_3}^--N$ concentrations ranges between 5 and 8 mg/L for biologically well-treated effluents. However, nitrate ions, ${NO_3}^-$, affects on oxidation as not only a well-known strong absorber of UV light below 250 nm of wavelength but also as an OH radical scavenger. The objective of this study was to evaluate the AOP systems for degradation of 2,4-DCP, and to delineate the effect of nitrate ions on UV oxidation of 2,4-DCP by conducting a bench-scale operation at various reaction times and initial concentrations of $H_2O_2$. The experimental results indicated that 2,4-DCP could be completely oxidized by $UV/H_2O_2$ process with an initial $H_2O_2$ concentration of 20 mg/L at a retention time of 1.0 min or longer. Nitrate ions did not show any adverse effect on 2,4-DCP oxidation at this high $H_2O_2$ concentration, and the practical initial $H_2O_2$ concentration and reaction time for the 80% oxidation turned out to be 5 mg/L and 1.0 min, respectively.

• 한국의학물리학회지:의학물리
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• 제14권3호
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• pp.175-183
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• 2003

최근 선량측정의 정확성을 향상시키기 위하여 기존의 공기커마 교정인수에 기반한 표준측정법에서 물 흡수선량 교정인수에 기반한 표준측정법으로 변환하고 있는 추세이다. 본 연구에서는 미국의학물리학회의 AAPM TG-51과 국제원자력기구의 IAEA TRS-398 표준측정법에 대한 선량교정 프로그램을 개발하였다. 이 프로그램은 윈도우 환경에서 사용이 용이하도록 비쥬얼 C++언어를 사용하여 각각의 표준측정법에서 권고하고 있는 방법 및 절차에 따라 사용자의 편의성을 고려하여 개발하였다. 이 프로그램은 이온함에 대한 정보와 물리적인 자료에 대한 표와 그래프 값들을 수식화하여 데이터베이스화함으로써 수작업으로 인해 발생할 수 있는 실수 및 오차를 줄일 수 있다. 개발된 프로그램의 활용을 통하여 국내 실정에 적합한 물 흡수선량 표준에 기반한 표준측정법 개발에 토대를 마련하는데 있어 기여할 것으로 사료된다.

• 대한지하수환경학회지
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• 제5권1호
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• pp.30-36
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• 1998

저분자량 유기산을 이용한 in-situ flushing 토양세척기법의 실제 현장 적용성 검토를 위해 실험실에서 회분식 실험을 통하여 적당한 세척제를 선정하고 이에 따른 여러 가지 운전변수를 찾아보았다. 대상 중금속으로는 Cu를 택했고, 세척제로는 실제 토양환경에 영향이 비교적 적은 저분자량 유기산인 acetic, citric, oxalic, succinic acid를 이용했다. 유기산을 이용하여 처리한 결과 실험에 사용된 유기산들 모두 1 mM의 저농도에서는 효과를 나타내지 못했고 50 mM 이상의 고농도에서 보다 좋은 제거율을 보였는데, 50 mM과 100mM의 경우 제거율이 큰 차이를 보이지 못했다. citric arid와 oxalic acid의 경우 중성 및 약산성 상태에서 최대의 제거율이 나타났고 특히 citric arid의 경우 87.1%의 높은 제거율을 보였다. 유기산이 없을때는 강산성 상태에서 Cu의 최고제거율이 70% 정도였다. 그러나 각 경우에서의 speciation을 살펴보면 유기산이 없을 경우에는 추출된 Cu의 대부분이 유해한 free ion상태로 존재하게 되고 유기산이 있을 경우에는 추출된 Cu의 대부분이 유기산과 complex를 이룬다는 것을 알 수 있었다.

• 한국의류학회지
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• 제18권5호
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• pp.661-673
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• 1994

We have gathered a fatty acid to recycle the waste oil of food manufacturing process, and then made a soap from the waste oil by alkali saponification. Effects of the washing elements such as the concentration of the soap, temperature and time were evaluated to find out the optimum washing conditions, and results are as follows. 1. We could find soaps made from the soybean oil (A), corn oil (B), rape seed salad oil (C), cotton seed oil (D) and a soap consisting of the each oil 25% respectively (I) had the lowest surface tension at the concentration of 0.225% -0.25%. Compared with the single fatty-acid soap, the multi-component soap I showed the lower surface tension at the cmc. 2. All the samples of A-I showed the lowest contact angle for the solid material at the concentration of 0.25%. The multi-component soap of I showed higher contact angle than the single.component soaps of A, B, C and D. 3. The soap G, made from the waste oil, show lower surface tension than 5, made from the complex raw fats of the eatable fatty oil acid and H, commercial soap. 4. The washing efficiency depends on the washing time. Especially the 25-minute was found to be the optimum washing time. 5. The highest washing efficiency was found at the 0.25% cont. reagardless of the washing temperature. At 0.15% concentration level the washing efficiency reduces as washing tem- perature increases. At 0.3% concentration level the highest washing efficiency was found between $50^{\circ}$-$60^{\circ}$. 6. The soap made from the waste oil showed the highest washing efficiency in terms of concentration, temperature, and time. 7. The soap made from the waste oil showed the similiar concentration of hydrogen ion to the synthetic detergent. 8. The hand value of the fabric washed by the soap made from the waste oil was a little lower value than those washed by the synthetic detergent.

• 자원환경지질
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• 제17권4호
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• pp.289-298
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• 1984

Uraniferous black slates of the Okchon sequence occur in Koesan (northeast) through Miwon-Boun (middle) to the southwest off Taejon (southwest) within the Okchon fold belt. The Uraniferous balck slates in the southwest off Taejon are particularly well developed in Chubu (northeast) and Moksso-ri (middle) areas whereas they are less developed in Jinsan (southwest) area. The uraniferous beds range from less than a meter to 40 meters in thickness and range from less than 0.02% $U_3O_8$ (cut-off-grade) to 0.05% $U_3O_8$ in the southwestern district off Taejon. Electron microprobe analysis of uranium-minerals found in graphitic slate samples enables to estimate their major compositions semi-quantitatively so that uraninite, ferro-uranophane and chlopinite are tentatively identified. Uranium-minerals are closely associated with carbon and metal sulfides. Correlation analysis of trace element concentrations revealed that U and F.C., and U and Mo are lineary correlative respectively and their correlation coefficients are positively high whereas those of U and V, U and Mn, and U and Zr are negatively low, implying that uranium mineralization has been closely related with concentrations of carbon and molybdenum. Stable isotope analyses of pyrite sulfur range widely from +11.5% to -23.3% in ${\delta}^{34}S$ values whereas those of graphite carbon fall within a narrow range between -23.3% and -28.9% in ${\delta}^{13}C$ values. The wide range of ${\delta}^{34}S$ values suggests that the sulfur could be of meteoric origin rather than of igneous source. The narrow range of ${\delta}^{13}C$ values, which are close to those of coal, indicates that the graphite is organic carbon in origin. Therefore, it is concluded that the uranium mineralization in the Okchon sequence took place primarily in sedimentary environment rich in organic matter and sulfide ion, both of which served as the reducing agents to convert soluble uranyl complex to insoluble uranium dioxide.

• 분석과학
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• 제12권6호
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• pp.515-520
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• 1999

Al(III)-thorin 착물에 대한 분광학적 정량 방법을 연구하였다. pH, 리간드와 계면활성제의 농도 및 안정화 시간에 대한 최적 조건을 결정하였다. thorin 리간드는 Fe(III), Ni(II), Cu(II), Pb(II) 그리고 Co(II)를 포함한 시료용액으로부터 Al(III)을 선택적으로 분리할 수 있도록 해준다. 여러 계면활성제중에서 비이온성인 Triton X-100에서 가장 안정한 상태를 나타냈고 수용액 중에서 Al(III)-Thorin-Triton X-100 착물은 526 nm에서 최대 흡광도를 가진다. 이 방법은 혼합된 시료용액에서 Al(III)을 정량하는데 이용되었다. 그리고, 분리 및 예비농축과정은 resoreinol-fermaldehyde 수지로 채워진 컬럼을 이용하였다. 컬럼 단계에서 수지의 흡착 능력은 pH변화에 매우 민감하기 때문에 pH를 조절하는 것이 필수적이다. 분리과정은 0.2 M acetic acid-sodium acetate 완충용액 (pH 4.5)와 1.0 M $HNO_3$용액으로 이루어졌다.