• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.87-105
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• 1991

The purpose of this experiment was to measure the leaking and solubility of commonly used dental restorative materials - Silux plus (CS), Hi-pol (CH), Clearfil F-II, Fissureseal (FS), Glass-Ionomer cement Fuji Type II (GI), Amalgam Cavex 68 (AM), Zinc Phosphate Cement (ZP) and gutta-percha (GP) and investigate the relation between the solubility and marginal leakage. Disc-shape specimens were fabricated with each material and dipped into deionized water, 0.01M lactic acid and 0.005M KOH solution, thus the total ionic concentrations in each solution was measured with ion chromatograph after 1, 3, and 7 days, respectively. For the solubility test, each specimen was immersed in 0.001M and 0.01M lactic acid for 24 hours, respectively and total weight loss was calculated. Also, Zn leaking through the margin of restorations was measured. The obtained results were as follows: 1. The amounts of eluted ion from the eight materials were most in 0.01M lactic acid and least in deionized water. 2. Of the eight materials, the fluoride release was greatest for glass ionomer cement (GI) in 0.01 M lactic acid after 7 days. 3. In analysis of the divalent cation, Mg was eluted most for zinc phosphate cement (ZP) and Ca for Clearfil F-II (CF) in 0.01M lactic acid after 7 days. 4. In analysis of transition metals, Cu and Zn were detected only. 5. The solubility rate of eight materials was greater in 0.01M lactic acid than in 0.001M for 24 hours, for zinc phosphate cement (ZP) the rate was greatest (5.4%) in 0.001M lactic acid, and amalgam least (0.01%). 6. The Zn concentration of restorative material with Z.P.C base was greater in 0.01M lactic acid than in 0.001M lactic acid.

• 한국식품저장유통학회지
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• 제12권5호
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• pp.501-506
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• 2005

본 연구에서는 유기산을 이용하여 칼슘 용해에 미치는 영향과 칼슘종류에 따른 용해특성을 조사하였다. 유기산종류에 따른 영향을 조사한 결과 해조칼슘은 초산과 젖산에서 잘 용해되었으나 구연산에서는 초기산도 4%이상에서 용해되었으며 주석산에는 칼슘이 용해되지 않았다. 초산과 젖산을 이용하여 칼슘종류에 따른 용해특성을 조사한 결과 초기산도가 높을수록 pH와 잔사량은 낮게, 적정산도는 높게 나타났다. 칼슘함량은 탄산칼슘과 해조칼슘에서 높았으며 젖산보다 초산이 칼슘가용화에 더 효과적인 것으로 나타났다.

• 대한치과보철학회지
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• 제43권1호
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• pp.1-14
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• 2005

Statement of problem. Among the physical properties of adhesion luting cement, the aspect that requires the most important factor is the degree of solubility and water sorption. Dissolution or an inadequate due to excessive water sorption inside the oral cavity compromises the while concurrently increasing the susceptibility to secondary dental caries. Susceptibility to dissolution and difficulty of removing remnant cement from the gingival sulcus have hindered the use of dental resin cement in the clinical practice, but the improved characteristics of newer generation resin cements have interest in and enabled resin cements to be widely used in adhesion of fixed prosthesis, such as laminate veneers and all-ceramic crowns. Purpose. The purpose of this study is to compare and analyze the degrees of solubility and water sorption of a variety of resin cements widely used for clinical purposes with different curing methods. Material and methods. Self-curing resin cements, $Avanto^{(R)}$, $C&B^{TM}$ CEMENT and Superbond C&B cements comprised group 1, 2 and 3. The dual-curing resin cements $Panavian^{TM}$ F, $Calibra^{(R)}$ and $Variolink^{(R)}$ II were divided into groups 4, 5, and 6, respectively. The investigation was carried out using disc-shaped specimens as specified by ANSI/ADA Specification No. 27. The degree of water sorption, water solubility and lactic acid solubility of each test group was analyzed statistically leading to the following conclusion. Results. The degree of water sorption was shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. There were significant differences between the water sorption of each group. Results of the degree of water solubility were shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. Statistically significant differences were found between each group, with the exception of groups 1 and 3. Finally, the degree of lactic acid solubility was found to increase in the following order : group 6,5,4,2,3 and 1. Significant differences were found between each group. In general dual-curing resin cements displayed substantially lower values than self-curing resin cements with regard to water sorption, water solubility, and lactic acid solubility. Conclusions. From the results of this study, dual-curing resin cements show a significantly lower degree of water sorption and solubility than their self-curing counterparts. Clinically, when selecting resin cements, the product with a lower degree of water sorption and solubility are preferred. The results of this study indicate that the use-of dual-curing resin cements is preferable to self-curing cements.

• 공업화학
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• 제31권5호
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• pp.475-480
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• 2020

Lactic acid와 키토산을 Cu(II) 이온과 반응시켜 합성한 착물을 사용하여 유기인 유사 독성물질인 DFP (Diisopropyl fluorophosphate) 분해반응에 적용하였다. Cu(II)-lactic acid 착물의 경우 homogeneous 상태에서 분해반응 반감기가 37. 1 min으로 분해성능이 우수하였다. 1 kDa 저분자량 수용성 키토산으로 합성한 Cu(II)-LMWS chitosan 착물은 결정화 후에는 용해도가 낮아 heterogeneous 한 상태에서 분해반응이 진행되었으며 그 반감기는 32.9 h이었다. 이 결과는 기존에 연구된 18 kDa 키토산 Cu(II)착물의 분해반응속도보다 약 16배 정도 증가된 것이다. Cu(II)-LMWS chitosan 착물을 결정화하지 않고 homogeneous한 상태로 진행한 분해반응에서는 반감기가 8.75 h로 용해도에 따라 약 4배의 차이를 확인할 수 있었다.

• KSBB Journal
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• 제26권1호
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• pp.13-18
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• 2011

본 연구에서는 $Ca(LA)_2$의 침전조건을 최적화하고 침전된 $Ca(LA)_2$ 용액에 황산을 처리하여 고순도, 고수율의 lactic acid를 회수할 수 있는 방법을 개발하고자 하였다. 특히 $Ca(LA)_2$의 용해도를 낮추기 위하여 여러 종류의 유기용매 첨가에 따른 영향을 평가하였다. 모델용액의 경우 침전을 위한 최적의 석회종류, 석회량, 교반속도, 시간, 온도, 유기용매 첨가량은 각각 CaO, 0.0175 g/mL, 220 rpm, 24 h, $5^{\circ}C$, ethanol 25% (v/v)이었으며 최적 조건 하에서 가장 높은 순도 (98%)와 수율(69%)을 얻을 수 있었다. 발효배양액 (lactic acid 순도: 69%, pH: 7.3)의 경우, 모델용액으로부터 얻은 최적의 조건 하에서 $Ca(LA)_2$ 회수 과정에서 64%, 회수된 $Ca(LA)_2$에 황산을 첨가 ($Ca(LA)_2/H_2SO_4$ molar ratio = 1:1)하여 lactic acid를 회수하는 과정에서 86%의 회수율을 각각 얻어 발효배양액으로부터 총괄 수율 55%로 lactic acid (순도: 88.6%)를 얻을 수 있었다.

• 대한화학회지
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• 제63권6호
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• pp.446-452
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• 2019

젖산을 이용하여 안전하게 양극활물질에 있는 Co, Mn, Ni을 침출할 수 있는 방법을 개발하였다. 양극활물질을 젖산으로 침출 시켰을 때, 젖산의 농도는 1N과 4 N 이상에서 보다는 2 N에서 가장 높은 효율을 보였다. 양극활물질을 단계적으로 젖산 용액에 첨가 하였을 때, 최대 용해도는 2 N의 젖산 용액에서 1 L 당 30 g이었다. 젖산 용액에 옥살산을 첨가하였고 희유금속들은 1 L 당 4 g에서 가장 경제적인 회수율을 보였다. 본 연구를 바탕으로 해서, 양극활물질로부터 희유금속들을 회수하기 위한 최적의 조건은 무게비로 옥살산과 양극활물질이 7 : 1이라는 것을 확인할 수 있었다. 첨가하여, 옥살산에 의해서 생성된 침전물은 Co, Ni, Mn 3성분이 결합되어 있는 다핵 결정성 물질이었다.

• KSBB Journal
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• 제21권3호
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• pp.199-203
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• 2006

본 연구에서는 에탄올 농도에 따른 모델용액과 발효액에서 여러 유기산들의 침전거동을 조사하였다. 발효액에서 에탄올의 농도가 높을수록 Ca(LA)2의 침전양이 많았다. Ca(LA)2의 침전효과는 발효액 내에서도 비슷하게 관찰되었다. 모델용액이나 발효액과의 혼합물 대비 30%(v/v)로 에탄올을 첨가하였을 때 젖산분리 공정의 불순물로 존재하는 다른 organic salt들의 침전율도 높았다. 따라서 전체 젖산회수공정의 효율에 대한 연구에서는 에탄올과 발효액의 혼합비율을 20%로 하였다. 반응증류시 일정 온도 이상에서는 젖산회수율이 차이나지 않았다. 에탄올이 첨가된 발효액에서는 대조군과 비교하여 최종젖산 회수율이 38.9% 증가하였다. 또한, 다른 유기산들을 포함한 회수액에서의 순도도 99.7%에 달하였다. 이러한 젖산 회수율의 증가는 owning-out crystallization에 의한 Ca(LA)2의 용해도 감소에 기인한 것으로 판단한다. 본 실험 이후에 더 높은 젖산 회수와 정제 효율을 얻기 위해서는 에탄올의 첨가에 따른 유기산의 거동과, 반응증류에서 사용되는 triethylamine의 양과 반응시간에 대한 검토가 필요할 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.88-96
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• 1990

The purpose of this study was to investigate the fluoride release and solubility of glass ionomer cement associated with three pH media. For this study, GC Fuji II discs (20.0mm in diameter ${\times}$ 1.5mm thick) were immersed in pH 4.0 lactic acid, pH 7.0 distilled water and pH 10.0 KOH solutions for 1, 7, 14 and 28 days. The amount of fluoride release from the cement into three pH media were measured by fluoride specific ion electrode and the solubility was measured by weight loss of discs. The results were as follows: 1. The lower was the pH of media, the more was the amount of release of fluoride. 2. The amount of fluoride release was increased with time lapse. 3. After I day, the solubility was the highest, and after 7 days that was the least. 4. The lower was the pH of media, the more was the solubility, but there was no statistical difference in solubility according to the pH change.

• 한국염색가공학회지
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• 제11권2호
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• pp.55-63
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• 1999

The purpose of this study was to investigate the purification of chitin and chitosan for textile finishing agent from crab shell. Weight loss rate(removing Ca and protein), degree of deacetylation, solubility and MIC(Minimum growth inhibitory concentration) value of chitosan and molecular weight of the treated crab shell were measured. The results of this study were as follows : 1) Weight loss rate(removing Ca) of crab shell treated with HCI increased with the concentration of HCI and treatment time, but it became constant over 60 min. of treatment time. 2) Weight loss rate(removing protein) of crab shell treated with NaOH(0.5N∼2N) increased with the concentration of NaOH and treatment temperature and time, but it became constant above loot of temperature and over 200 min. of treatment time. 3) Degree of deacetylation of chitin treated with NaOH increased with the concentration of NaOH(40∼60％), but molecular weight decreased and thus MIC value increased. 4) Concentration of acetic acid should be above 0.3％ to dissolve chitosan easily. Solubility for chitosan was the highest with formic acid, and the next was acetic acid, hydrochloric acid, lactic acid and sulfuric acid in order.

• 한국식품저장유통학회지
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• 제24권5호
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• pp.559-564
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• 2017

Probiotics로 알려진 유산균을 다량 포함하고 있으며 우유가 가지고 있는 영양성분을 함유한 액상형 요구르트를 사용하여, 저장성은 높지만 편리성이 낮은 분말형 요구르트의 단점을 개선한, 유동성 및 용해성이 우수한 구형과립 요구르트를 제조하였다. 구형과립 요구르트의 유동층코팅기 최적 제조조건은 반응표면분석방법(RSM design)을 이용하여 설정하였으며, feeding rate(FR) 0.54 mL/min, atomization air pressure(AP) 2.64 bar, product temperature(PT) $58.18^{\circ}C$의 유동층코팅기 운영조건하에서 최대회수율은 79.42%로 예측되었다. 유동층코팅기의 버텀스프레이 방식으로 제조된 구형과립 요구르트는 6-7 log CFU/g의 많은 유산균을 가지고 있었으며, 특히 상대습도 75% 및 저장온도 $25^{\circ}C$ 조건하에서 4개월 동안 유산균수의 감소가 아주 미미하여, 저장성 및 편리성이 증진된 새로운 형태의 유산균 제품 개발에 대한 가능성을 보여주었다.