• 한국미생물·생명공학회지
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• 제25권6호
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• pp.537-545
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• 1997

The aim of the present research program was to isolate a strain of actinomycetes producing antifungal substance. Soil samples were collected from various sites in Korea and a number of actinomycetes were isolated from the soil samples by applying selective agar for actinomycetes. Among isolates, a strain (NA -52) producing antifungal substance against Pyricularia oryzae was selected. Chemotaxonomic and numerical identification were carried out for the isolate. Fifty taxonomic unit characters were tested and the data were analyzed numerically using TAXON program. The isolate was identified as a synonym of streptomyces diastaticus belong to cluster No. 19 (Streptomyces diastaticus). But it showed a low similarity to S. diastaticus in simple matching coefficients, hence it was considered as one new species in Streptomyces.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.303-304
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• 2023

In this study, the effects of NaOH and KOH alkali activators of various concentrations on the performance of alkali activated waste concrete powder (WCP) was discussed. The samples activated by alkaline solutions were cured for up to 28 days and then compressive strength test was performed. These samples were also characterized using various techniques to explore the phase evolution, and microstructural changes. Results showed superior performance of NaOH-activated WCP. Additionally, activation of WCP by 8M concentrated alkali solutions improved the strength, reactivity and microstructure of alkali activated WCP binder sample.

• 한국산학기술학회논문지
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• 제11권7호
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• pp.2565-2569
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• 2010

실리콘 태양전지 셀을 제작하고 효율을 측정하는데 있어 texturing 효과에 대하여 상관성을 조사하였다. Texturing은 $HNO_3$, KOH, NaOH를 각각 사용한 IPA혼합 에칭용액을 만들어서 샘플을 제작하였다. 셀의 분석은 FTIR 과 XRD를 이용하였으며, 실리콘 태양전지 셀의 효율과 화학적인 특성 사이의 상관성을 조사하였다. FTIR 데이터의 950~1350 $cm^{-1}$ 영역에서 픽의 생김새와 셀 표면의 반사도 사이에는 상관성이 있으며, 픽의 쪼개짐이 많으면 표면에서 결합의 상호작용이 활발하지 않다는 것을 의미하며 이러한 표면에서 반사가 잘 일어나지 않으면서 효율이 증가하는 것을 확인하였다.

• Journal of the Korean Data and Information Science Society
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• 제25권1호
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• pp.263-269
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• 2014

When the loss of samples appears under repeated surveys, new samples can often replace missing values. Estimators using response probability can be considered under repeated surveys on two occasions where new samples are selected instead of missing data on the second occasion. We propose a new estimator that uses both respondents and new samples on the second occasion. It is considered for the simulation setting that missing values can happen at the second occasion and are replaced by new samples. We can see that the proposed estimator is more efficient than that using a weighting adjustment method for respondents at the second occasion.

• 대한수의학회지
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• 제50권3호
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• pp.205-211
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• 2010

Fifty young calves, about five to six months old purchased from nation-wide were investigated with the prevelance of neutralizing antibody (Ab) of infectious bovine rhinotracheitis virus (IBRV), parainfluenza 3 virus ($PI_{3}V$), bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV). The positive detection ratio of neutralizing Ab against IBRV was only 3% and two of positive samples showed low antibody titer (below 2). Ab against BRSV showed 48% of positive ratio and among 24 positive samples, antibody titer of 23 samples were below 3. But in the case of BVDV, 68% of samples were positive and 23 samples appeared to possess high antibody titer, above 4 and the antibody titer of five samples were above 8. The highest positive result came from $PI_{3}V$. The positive ratio in the samples investigated in this study was 72%, but the antibody titer of positive samples were generally below 3 (77.8% in positive samples).

• 한국세라믹학회지
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• 제47권3호
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• pp.249-255
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• 2010

To investigate optical properties of (V, Pr)-doped $ZrSiO_4$ green pigments, samples were prepared by the ceramic method using NaF and NaCl as mineralizers. They were characterized by X-ray diffraction, UV-Vis spectroscopy and Raman spectroscopy. The changes of color in the samples during heating and effect of mineralizers were studied in terms of valence of the vanadium and praseodymium in the zircon matrix. (V, Pr)-doped $ZrSiO_4$ pigments give rise to green coloration in $800^{\circ}C$. The oxidation state of V and Pr ions of pigments in the glazed samples were confirmed by UV-Vis absorption spectra. This absorption spectra showed three typical bands of trivalent Pr at the 445, 480~490, 592 nm due to f-f transitions and two broad bands of 302~380, 400~500 nm due to f-d transitions of tetravalent Pr. According to the increasing amounts of $Pr_6O_{11}$, the two broad bands showed decreasing intensity at 290, 640 nm due to d-d transitions of tetravalent V.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.477-482
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• 2011

The structural analysis of polytrimethylene terephthalate (PTT) and characterization of the hydrolytic degradation products after acid hydrolysis were performed using MALDI-TOF mass spectrometry. Mass spectra of the PTT samples were analyzed using a self-calibration method as well as an internal calibration method with standard materials of known masses. PTT structures constituting the samples were determined from the analyses of the spectra, and their relative compositions were estimated. The MALDI-TOF mass spectra of the acid-hydrolyzed PTT sample showed three main series of oligomer products with different end groups in accordance with the hydrolysis schemes. From the spectra of both $Na^+$ and $K^+$ adducts, it was concluded that the PTT samples have higher affinity for $Na^+$ compared with $K^+$ and therefore show higher ionization efficiency with sodium ions when dithranol is used as a matrix. Two different wavelength laser beams ($\lambda$ = 337 nm and 355 nm) were tested and it was observed that the 355 nm beam was more efficient in obtaining the MALDI spectra of PTT using dithranol as a matrix under our experimental conditions.

• 소성∙가공
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• 제15권3호
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• pp.213-219
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• 2006

To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous phase inside glass. In this study, Ag-doped $45SiO_2-24CaO-24Na_2O-4P_2O_5\;and\;70SiO_2-10CaO-24Na_2O-10TiO_2$ glasses were irradiated to strengthen by crystallization using femto-second laser pulse. XRD, Nano-indenter and SEM etc., irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value($4.4{\sim}4.56^*10-3Pa$) of elastic modulus which related with strength of glass than values heat-treated samples and these are $1.2{\sim}1.5$ times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.

• Journal of Microbiology
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• 제45권1호
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• pp.48-52
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• 2007

A new procedure for the concentration of nonoviruses from water samples has been developed. This procedure (calcium flocculation-citrate dissolution method) uses the following steps: virus flocculation formed by treatment with 1 M $CaCl_2$ and 1 M $Na_2HPO_4$, virus release by sodium citrate dissolution (0.3 M Na citrate, pH 3.5), and virus re-concentration by ultrafiltration. When reverse transcription (RT)-PCR was performed after the procedure, the overall detection sensitivity for seeded noroviruses in a one liter drinking water sample was as low as 1 RT-PCR unit, which is equal to a $10^{-6}$ dilution of the virus sample. This approach showed at least a 5-fold-higher sensitivity than the current method with its three steps of adsorption-elution-concentration. The newly developed procedure was used to test different brands of bottled drinking water from China for putative contamination with noroviruses. A total of 144 samples were analyzed; all of the samples were negative for norovirus specific nucleic acids.

• 분석과학
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• 제12권4호
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• pp.273-278
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• 1999

수은과 비소를 동일한 반응조건으로 환원 증기 발생법-유도결합 플라즈마 원자방출 분광계로 동시에 분석할 수 있는 방법을 연구하였다. 수은과 비소는 휘발성이 강하므로 시료를 마이크로파 용해 장치와 산을 이용한 추출법으로 전처리를 실시하였다. 환원 증기 발생법 반응조건은 6N HCl과 2% $NaBH_4$로 비교적 농도를 진하게 사용하였으며, 이 조건에서 검출한계는 수은과 비소가 각각 0.06 ppb, 0.08 ppb를 얻었다. 수은은 모두 표준시료의 검증값에 일치하였으며 비소도 무기물 시료에서는 검증값에 일치하였으나 유기물 시료에서는 약 80%의 회수율을 얻었다.