• 동의생리병리학회지
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• 제18권4호
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• pp.1098-1101
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• 2004

This study was carried out to investigate the solubility of the ingredients of the kidney stone in the solution of the traditional oriental medicines. Calcium hydroxide, apatite and uric acid were chosen as the ingredients of the kidney stone. Plantaginis Semen, Lysimachiae Herba, Saururi Herba seu Rhizoma, Imperatae Rhizoma, Allium tuberosum Rottler were studied as the oriental medicines for the kidney stone. Calcium hydroxide had showed the very good solubility in the solution of Imperatae Rhizoma, the apatite had showed the good solubility in the solutions of Saururi Herba seu Rhizoma and Allium tuberosum Rottler. Uric acid had showed the mild solubility in the solution of Lysimachiae Herba and Saururi Herba seu Rhizoma.

• The Korean Journal of Ceramics
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• 제2권2호
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• 대한화학회지
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• 제5권1호
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• pp.1-6
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• 1961

It is important to study hydrazine because of the development of new uses for its derivatives. The Rasching method is the only satisfactory one for synthesizing hydrazine; it involves the oxidation of ammonia by sodium hypochlorite in the presence of some such catalyst as gelatin. Calcium hypochlorite was substituted for the sodium hypochlorite particularly in this work, applying agar-agar as catalyst. The results of the experiments are as follow: 1. The yield is proportional to the mole-ratio of ammonia to available chlorine in calcium hypochlorite and about 60% is obtained when the ratio is 20. 2. Agar-agar can be used as a catalyst and its proper concentration in the solution is 0.005%. 3. Proper concentration of available chlorine in the reaction solution is 0.23 mole/l. 4. The most effective condition for the reaction is a temperature of $60{\sim}65^{\circ}C.$ maintained for $20{\sim}25min$. 5. The reaction takes place equally well in either an open or closed container. 6. When calcium hypochlorite is applied in place of sodium hypochlorite, the yield of hydrazine is increased as much as 17%. 7. The yield of hydrazine is decreased by eliminating the suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite. 8. When $Ca(OH)_2$ is added to Rasching process, the yield of hydrazine is raised normally. 9. The fact that some metal ions, such as $Cu^{++},$ inhibit the formation of hydrazine was proved. 10. The suspension of $Ca(OH)_2$ acted as a remarkable adsorbent for $Cu^{++}$ like gelatin. The suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite acts as a catalyst, absorbing metal ions, to increase the yield of hydrazine. So I think that calcium hypochlorite is a more efficient oxidant than sodium hypochlorite in hydrazine syntheses.

• 공업화학
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• 제3권3호
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• pp.522-526
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• 1992

반응온도 $10^{\circ}C$하에서 수산화칼슘 수용액에 $CO_2$ 가스를 흡수시켜 탄산화반응을 행하였으며 비정질탄산칼슘의 생성과 전이과정을 조사하였다. 생성된 비정질탄산칼슘은 입경 약 $0.02{\sim}0.05{\mu}m$ 정도인 구형의 초미립자로서 소량의 부착수를 포함고, $HCO^-_3$ 이온이 일부 치환된 비화학양론적인 물질이었다. 이 물질은 매우 불안정하여 반응액 내에서 쉽게 안정한 calcite로 전이하게 되는데 반응액 내의 탄산기가 $CO_3^{2-}$ 이온 지배적인 경우에는 연쇄상 calcite로 전이하였고, $HCO^-_3$ 이온 지배적인 경우에는 능면체 calcite로 전이하였다. 그러므로 비정질탄산칼슘의 전이과정을 적절히 제어함으로써 탄산칼슘 입자의 형태와 크기를 조절하는 것이 가능할 것으로 생각된다.

• 한국식품과학회지
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• 제22권2호
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• pp.116-122
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• 1990

두부의 응고제와 침지액을 달리하여 저장 중 침지액의 미생물상과 이화학적인 변화를 검토하였다. 두부는 HAc로 응고시키는 것이 $CaCl_2$보다 저장성 향성에 효과적이었고 $CaCl_2$로 제조한 두부는 $30^{\circ}C$에서 15-17시간만에 부패가 시작되어 세균수는 $10^7cells/ml$에 달하였다. 침지액은 0.1% HAc용액이 3% NaCl 용액이나 0.1% K-sorbate용액보다 두부저장에 효과적이었다. 침지액의 탁도는 두부가 부패함에 따라 비례적으로 증가하였으며 3% NaCl이나 0.1% K-sorbate 용액에 침지할 때 탁도의 증가는 심하였다. 두부의 부패가 진행될수록 침지액의 적정산도와 아미노태 질소량은 증가하였으며 pH는 1-2일 후에 증가하였다.

• 한국농공학회논문집
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• 제61권6호
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• pp.103-110
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• 2019

The purpose of this study is to investigate the reaction mechanism of soil and bacteria solution by various mixing ratios. For this purpose, in order to understand the reaction mechanisms of microorganisms and weathered granite soil, the tests were carried out under various mixing ratios additives such as soil, bacteria solution, $Ca(OH)_2$ and fixture. The test results from this study are summarized as follows. Firstly, the reaction between the bacteria solution and fixture produced a precipitate called vaterite, a type of silicate and calcium carbonate. Secondly, as a result of SEM analysis, the resulting precipitates generated from the test results using the specimens with various mixing ratios except SW condition and the irregular spherical microscopic shapes were formed in the size of $150{\mu}m$ to $20{\mu}m$. In addition, it can be seen that the bacteria solution and the fixture reacted between the granules to form an adsorbent material layer on the surface, and the microorganisms had a biological solidifying effect when the pores are combined into hard particles. Finally, The XRD analysis of the sediment resulting from the reaction between the microorganism and the deposit control agent confirmed the presence of a type of calcium carbonate ($CaCO_3$) vaterite, which affects soil strength formation, as well as silicate($SiO_2$).

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권1호
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• pp.1-14
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• 2023

In this study, column tests using relatively uniform Jumunjin sand media were conducted to evaluate the feasibility of calcium polysulfide (CaS_x, CPS) in removing high concentration of Zn²⁺ in groundwater. The injected CPS solution reacted rapidly with Zn²⁺ in artificial groundwater and effectively reduced Zn²⁺ by more than 99% through metal sulfide precipitation. Since the density (d = 1.27 g/cm³ ) of CPS solution was greater than that of water, CPS solution settled down rapidly while capturing Zn²⁺ and formed stable CPS layer similar to dense nonaqueous phase liquid. Mass balance analysis on Zn²⁺ in CPS solution suggested that CPS solution effectively reacted with Zn²⁺ to form metal sulfide precipitates except for high groundwater seepage velocity of 400 cm/d. With greater groundwater seepage velocity, injected CPS did not completely dissolve at the CPS-water interface, but a partially-misible CPS layer continuously moved and reacted with Zn²⁺+ in the direction of groundwater flow. Since hydraulic conductivity (K_h) decreased slightly due to the generated metal precipitates in the inter-pores of media, injection of CPS solution should be optimized to prevent clogging. As evidenced by both XRF and SEM/EDS results, ZnS precipitates were clearly observed through the reaction between the CPS solution and Zn²⁺. Further study is warranted to evaluate the feasibility of CPS to remove high-concentration heavy metalcontaminated groundwater in complex and heterogeneous media.

• 한국환경과학회지
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• 제9권5호
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• pp.437-441
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• 2000

A study on the removal of Pb ion from Pb-contaminated soil was carried out using ex-site extraction process. Tartaric acid (TA) and iminodiacetic acid sodium salt(IDA) as a washing agent were evaluated as a function of concentration reaction time mixing ratio of washing agent and recycling of washing agent. TA showed a better extraction performance than IDA. The optimum washing condition of TA and IDA were in the ratio of 1:15 and 1:20 between soil and acid solution during 1 hr reaction. The total concentrations of Pb ion by TA and IDA at three repeated extraction were 368.8 ppm and 267.5 ppm respectively. The recovery of Pb ion from washing solution was achieved by adding calcium hydroxide and sodium sulfide form the precipitation of lead hydroxide and lead sulfide and optimum amounts of sodium sulfide and calcium hydroxide were 7 g/$\ell$ for the TA washing solution and 4 g/$\ell$, 5g/$\ell$ for the IDA washing solution respectively. The efficiency of recycle for TA and IDA washing solution were 78.8% , 95.1%, and 89.2%, 96.6% at third extractions under $Na_2S$ and $Ca(OH)_2$, respectively.

• Applied Biological Chemistry
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• 제40권6호
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• pp.531-535
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• 1997

폐기물로 버려지고 있는 난각에 다량으로 포함되어 있는 칼슘을 효율적으로 회수하고, 이온화 정도를 높일 수 있는 방법을 조사하였다. Ball mill을 이용해 난각을 분쇄해 물속에서 비중의 차이를 이용하여 난각분을 얻었고, 회전속도 30 rpm, 체류시간 30분, volume fraction 0.08에서 가장 높은 난막 제거 효과를 보였다. 난각분을 전기로에서 회화시켜 얻은 난각칼슘분의 백색도를 측정해 L값이 90이상에 도달하는 시간은 전기로 온도 850, 900, $1000^{\circ}C$에서 각각 14, 9, 3시간이 소요 되었으며, 난각칼슘분의 Hausner ratio는 1.43으로 조사되었다. 난각칼슘분은 물, 초산, 구연산, 젖산$(0.05{\sim}3%)$ 용액에서 각각 990, 3500, 3900, 4200 ppm의 이온화 정도를 나타내었다. Calcium-citrate-malate complex(CCM), calcium-citric acid complex(CC), calcium-malic acid complex(CM)는 물에서 이온화 정도가 난각칼슘분에 비해 약 4-5배 증가 하였다.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.379-390
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• 1998

In endodontic treatment, calcium hydroxide has been used as intracanal medicament. Although calcium hydroxide should be removed thoroughly before permanent root canal filling, no effective method for its removal has been reported. Because of irregularity of root canal walls, root curvatures and anatomic variations, it is insufficient to remove calcium hydroxide from the canal wall only by mechanical instrumentation Considering the chemical effects of irrigants on calcium hydroxide, $Ca^{++}$ dissolving effect from two calcium hydroxide products is investigated, using dis- tilled water, NaOCl, citric acid and EDTA. Vitapex$^{(R)}$ 0.1g and calcium hydroxide 0.03g were dissolved in distilled water, 5% NaOCl, 50% citric acid and 17% EDTA respectively, at 1, 3, 5, 10min. time interval. The solution was filtered using filter paper(pore size $5{\mu}m$) and $Ca^{++}$ concentration was determined by ion chromatography. The result were as follows : 1. Distilled water, NaOCl, citric acid and EDTA abstracted more $Ca^{++}$ from calcium hydroxide than Vitapex$^{(R)}$ except NaOCl 1, 5, 10 time interval. 2. EDTA and citric acid abstracted more $Ca^{++}$ from Vitapex$^{(R)}$ and calcium hydroxide than distilled water or NaOCl. The overall result support the view that water-based calcium hydroxide product is easily removed than oil-based calcium hydroxide product and EDTA, citric acid are more effective in $Ca^{++}$ elution than NaOCl or distilled water.