• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.805-810
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• 2008

Using metallic Ti powder as raw materials and 1,2-diaminocyclohexane (DACH) as the trial template, two novel reduced titanophosphate open-structures were hydrothermally isolated by varying the $H_3PO_4/H_2O$ ratio to adjust the pH value. TiPO-1 crystallizes in orthorhombic Pbca space group with cell parameters a = 21.956(3) $\AA$, b = 8.6268(11) $\AA$, c = 7.2883(9) $\AA$, V = 1380.5(3) $\AA^3$, Z = 4. TiPO-2 crystallizes in triclinic space group P$\bar{1}$ with parameters a = 5.1620(10) $\AA$, b = 8.815(2) $\AA$, c = 10.655(3) $\AA$, $\alpha$ = $99.45^{\circ}$, $\beta$ = $102.94^{\circ}$, $\gamma$ = $91.06^{\circ}$, V = 465.34 $\AA^3$. TiPO-1 is constructed by infinite -Ti-O-Ti-O- linkage that is capped by $PO_4$ groups to form a chain structure with protonated DACH molecules occupying the interchain spaces. TiPO-2 represents a rare 3-D reduced titanophosphate with 12-MR channels. The structure of TiPO-2 is a neutral framework with water molecules located in the channels.

• Restorative Dentistry and Endodontics
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• 제24권1호
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• pp.156-165
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• 1999

The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength between new and old composites. Circular cavities prepared on the center of acrylic resin mold and the prepared cavities were filled with composite resin. They randomly assigned into control group and 8 groups according to the difference in surface treatments of old composites; Control group: no surface treatment, Group 1: surface treated with #120 SiC paper & bonding agent, Group 2: surface treated with #400 SiC paper & bonding agent, Group 3: surface treated with #120 SiC paper, 32% $H_3PO_4$ & bonding agent, Group 4: surface treated with #400 SiC paper, 32% $H_3PO_4$ & bonding agent, Group 5: surface treated with #120 SiC paper, primer & bonding agent, Group 6: surface treated with #400 SiC paper, primer & bonding agent, Group 7: surface treated with #120 SiC paper, 32% $H_3PO_4$, primer & bonding agent, Group 8: surface treated with #400 SiC paper, 32% $H_3PO_4$, primer & bonding agent. New composites were applicated on the old composites of experimental groups. The shear bond strengths for the experimental specimen were measured and the results were analyzed by using one way ANOVA. The observations of surface morphology after SiC paper roughening and debonded surface morphology after shear bond strength test were done by SEM. The results were as follows; 1. Shear bond strengths for specimens roughened with #120 SiC paper matching with the particle size of coarse diamond bur were significantly higher than those for the specimens with #400 SiC paper(P<0.05). By SEM, the surface of the specimens roughened with #120 SiC paper was more irregular than the specimens with #400 SiC paper. 2. Shear bond strengths for specimens treated with 32% $H_3PO_4$ etchant, primer, bonding resin were significantly higher than those for specimens treated with 32% $H_3PO_4$ and bonding resin(P<0.05). 3. Shear bond strengths for the specimens treated with 32% $H_3PO_4$ etchant and bonding resin were significantly higher than those for specimens treated with only bonding resin(P<0.05). There was no remarkable change of surface morphology after 32% $H_3PO_4$ etching. 4. It was possible to observe mixed fracture patterns (the cohesive fracture of old composite and the adhesive fracture between old and new composite) in the specimens roughened with #120 SiC paper, but almost adhesive fracture in the specimens roughened with #400 SiC paper.

• 미생물학회지
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• 제46권1호
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• pp.27-32
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• 2010

저농도 유기물, 질소, 인 제거를 위하여 독립영양 미생물인 광합성 박테리아를 이용한 회분식 실험 결과 초기값 $COD_{Cr}$ 37.3 mg/L, $NH_3$-N 4.0 mg/L, $PO_4^{3-}$-P 1.0 mg/L (C:N:P=100:10:1) 일 때 각각 87.4%, 46.3%, 79.7% 제거효율을 보였다. 혼합 광합성 박테리아, 세라믹 담체 및 담체 KSP01을 적용한 폭기식 반응기 실험 결과, 평균 유기물 72.7%, 암모니아성 질소 79.2%를 제거하였으며, pH 조절로 인산염 인을 최대 92.6%까지 제거할 수 있었다. 반응기 내 다양한 폭기 조건에서 암모니아성질소 제거를 확인한 결과, 1, 2 반응조에 10.2 L/min로 공기를 주입하였을 때 98.5%로 높은 제거효율을 보여주었다. 또한 하천수 적용시 암모니아성 질소 82.8%의 높은 제거효율을 확인하였다. 본 연구를 통하여 개발된 정화 시스템의 현장 적용시 저농도 질소, 인의 높은 제거를 보일 것으로 사료된다.

• 한국수자원학회논문집
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• 제33권2호
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• pp.145-157
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• 2000

본 연구에서는 금강 대청댐하류의 본류구간에서 갈수시간에 대해서 WASP5모형 중에서 수질모의 부분인 EUTRO5모형과 1차원 정상류 수리모형인 HEC-2모형을 연계한 수질모형을 이용하여 대청조정지댐으로부터 강경수위표 지점까지 수질의 변화를 모의하였다. 수질 및 유량자료의 수집을 위하여 대청댐으로부터 금강하류에 위치한 주요 수위표지점에서 1998년 12월, 1999년 1월과 3월의 3회에 걸쳐 관측하였다. 수질모의모형은 1999년 1월 자료를 이용하여 보정되어지고, 1998년 12월자료와 1999년 3월자료를 이용하여 검증되어졌다. 모형에 의해서 모의된 수질변수들의 거리에 따른 변화는 1999년 3월자료를 이용하여 모의된 chlorophyll-a, BOD5, NH3-N, PO4-P와 같은 수질변수를 제외하고는 관측된 수질변수값과 거의 일치하였다. 또한 NH3-N과 PO4-P가 증가 혹은 감소되어 갑천과 미호천으로부터 금강본류로 유입된다고 가정하는 경우에 금강본류에서의 chlorophyII-a의 농도를 모의하였다. 모의한 바에 의하면 갑천과 미호천에서 NH3-N과 PO4-P가 70% 감소되어져 금강본류로 유입된다고 가정하는 경우를 제외하고는 거의 미미한 chlorophyII-a 농도변화율을 보였다.

• 한국세라믹학회지
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• 제33권1호
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• pp.7-16
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• 1996

${CO_3}^{2-}$ containing whisker-like hydroxyapatite powders were synthesized byhomogeneous precipitation method using urea, Dicalcium phosphate anhdrate[DCPA; $CaHPO_4$] and octacalcium phosphate [OCP; $Ca_8H_2(PO_4_)6\cdot5H_20$]were obtained as precursors and they transformed to high crystalline hydroxyapatites at pH 5.62, and 6.54 respectively. According to the condition of the final pH in the solutions for the solution products and urea contents OCP was remained. When the solution product of $Ca^{2-}$ and ${PO_4}^{3-}$ was $1.5\times 10^4$[$mM^2$] and the content of urea was 0.25 mol.$dm^{-3}$ well crystallized whisker-like hydroxyapatite tens of micrometer in length was obtained. By heat treatment DCPA and OCP were decomposed into $\beta$-tricalcium phosphate [$\beta$-TCP ; $\beta$-$Ca_3{PO_4}_2$] and $\beta$-dicalcium phosphate [$\beta$-DCP ;$\beta$-$Ca_2P_2O_4}_2$]. And well-crystallized hydroxyapatite was partially decomposed into $\beta$-TCP at $800^{\circ}C$.

• 한국산학기술학회논문지
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• 제1권1호
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• pp.27-32
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• 2000

인산염계 Ag₂OㆍLi₂OㆍCaOㆍTiO₂ㆍP₂O/sub 5/ 조성에 CuO를 0.05∼l.5 mole 첨가하여 다공성 글래스 세라믹스를 제조하였으며. 제조된 모유리는 최적 핵형성을 위해 610℃. 최고 결정성장을 위해 840℃에서 열처리하였다. 1N-HC1에서 β-Ca₃(PO₄)결정상만을 선택적으로 용출하였으며 LiTi₂(PO₄)₃상과 AgTi₂(PO₄)₃결정상이 존재하는 Glass Ceramics를 제조하였다. 다공성 글래스 세라믹스의 항균효과 및 특성을 평가하였다. Staphylococcus aureus와 Salmonella typhi 균이 본 연구에 사용되었으며, 탁월한 항균효과를 나타내는 것으로 평가되었다.

• 한국환경과학회지
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• 제8권2호
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• pp.171-176
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• 1999

To estimate the residence times of aerosols in air, the activities of $^{210}Pb$ and $^{210}Po$ in aerosols were measured at 4 sites in Pusan. All aerosol samples were collected by a high volume air sampler from January to October 1996. The activities $^{210}Pb$ and $^{210}Po$ in Pusan were varied from 11.77 to 67.57 dpm/1000$m^3$ and from 2.63 to 15.91 dpm/1000$m^3$, respectively. The mean activities were 34.62 dpm/1000$m^3$ for $^{210}Pb$ and 8.24 dpm/1000$m^3$ for $^{210}Po$. The highest values of the activities of $^{210}Pb$ and $^{210}Po$ were appeared at P3 site and the lowest values at P4 site. During the sampling period, the trends of the activities of $^{210}Po$ and $^{210}Pb$ were similar to total suspended particulate matter(TSP) concentrations. The mean residence times of atmospheric aerosols calculated from $^{210}Po$/$^{210}Pb$ activity ratio was about 60~80 days in Pusan. The longest residence time of atmospheric aerosols was in January because of the lack of rainout and washout, but the shortest residence time was in August, largely due to scavenging effect by frequent rains. The activities of $^{210}Po$ and $^{210}Pb$ in atmospheric aerosols were different in time and space, which seems that the distribution of $^{210}Po$ and $^{210}Pb$ activities and scavenging processes in air may be controlled by the local and meteorological conditions.

• 멤브레인
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• 제26권2호
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• pp.108-115
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• 2016

비료를 유도용액으로 사용하는 정삼투를 하수처리수(2차 침전지 유출수)의 재이용에 적용하여 유도용액의 성능을 평가하였다. 일반적으로 많이 사용되고 있는 비료 중에서 삼투압, 용해도 및 pH 등을 고려하여 $NH_4H_2PO_4$, KCl, $KNO_3$, $NH_4Cl$, $(NH_4)_2HPO_4$, $NH_4NO_3$, $NH_4HCO_3$ 및 $KHCO_3$을 유도용액 후보군으로 선정하고, 수투과선속 및 역용질선속을 측정하여 유도용액의 성능을 평가하였다. 평균 수투과선속은 KCl > $NH_4Cl$ > $NH_4NO_3$ > $KNO_3$ > $KHCO_3$ > $NH_4HCO_3$ > $NH_4H_2PO_4$ > $(NH_4)_2HPO_4$의 순서로 나타났으며, KCl을 유도용액으로 사용하였을 때, 평균 수투과선속은 13.49 LMH이었다. 하수처리장 2차 침전지 유출수의 삼투압은 탈이온수의 삼투압에 비해 큰 차이가 없었다. 역용질선속은 $NH_4H_2PO_4$ < $NH_4Cl$ < $(NH_4)_2HPO_4$ < $KNO_3$ < $NH_4HCO_3$ < $NH_4NO_3$의 순서로 나타났으며, $NH_4H_2PO_4$를 유도용액으로 사용하였을 때, 역용질선속은 $4.96{\times}10^{-3}mmol/m^2{\cdot}sec$이었다.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.63-67
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• 2016

Divalent europium-activated $Ca_2PO_4Cl$ phosphor powders were prepared by a chemical synthetic method followed by heat treatment in reduced atmosphere, and the crystal structures, morphologies and photoluminescence properties of the powders were investigated by x-ray powder diffraction, scanning electron microscope and spectrometer. The effect of Ca/P mole ratio at the starting materials on the final products was evaluated. The optimized synthesis condition obtained in this study was Ca/P mole ratio of 2.0. The present phosphor materials had higher photoluminescence intensity and better color purity than the commercial blue phosphor powders, $(Ca,Ba,Sr)_{10}(PO_4)_6Cl_2:Eu^{2+}$. The result of excitation spectrum measurement indicated that the excitation efficiency of the synthesized powders was higher for the long-wavelength UV region than that of the commercial phosphor. It was thus concluded that the samples prepared in this study can be successfully applied for the light-emitting devices such as LED excited with long-wavelength UV light sources.

• 한국인쇄학회지
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• 제2권1호
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• pp.71-75
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• 1984

NiNH$_{4}PO_{4}$ was Prepared from waste Ni catalyst used in hydrogenation of oil and fat, NiNH$_{4}PO_{4}$ was calcined at different temperature respectly 800, 1000, 1100$^{\circ}$C to prepare Nickel yellow. The results from this experiment are summerized as follow: 1) Nickel yellow formed at 1100$^{\circ}$C was most clearness yellow color from color analyzer data. 2) Nickel yellow was consist of ${\alpha}-Ni_{2}P_{2}O_{7}$, $Ni_{3}(PO_{4})_{2}$ from X-ray diffraction analysis. 3) The endothermic pick at 100$^{\circ}$C and exotherwic pick about 1050$^{\circ}$C on calcination of NiNH$_{4}PO_{4}$ were checked in DTA (difference thermal analysis data)