• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1301-1302
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• 2008

In this study, the fracture strength for fracture mechanism porous calcium phosphate made from sintered with ${\beta}$-tricalcium phosphate obtained by wet precipitation procedure is analyzed using finite element method and experiment measurement. First, three $3{\times}3{\times}3mm^3$ and $5{\times}5{\times}5mm^3$ specimens are prepared and tomographic images of one $5{\times}5{\times}5mm^3$ specimen are obtained by micro focus X-ray CT. The compression tests using the specimens are carried out to measure the elastic modulus and fracture strength to analyze the fracture mechanism of porous calcium phosphate specimen. The tomographic images are reconstructed by 3D reconstruction program. The finite elements are directly built up in the reconstructed specimen. The numerical simulation for the compression tests is performed using the element. The mechanism of calcium phosphate of simulation are obtained by the compression tests using there cylindric specimen of height 19.5 mm and diameter 10 mm. From the results, the applicability of porous calcium phosphate is evaluated to care fracture and vacant bone of a patient as the reinforcement material.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.157.2-157.2
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• 2007

• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.871-879
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• 2007

Purpose: The purpose of this study was to evaluate the bone regeneration of novel biodegradable amorphous calcium phosphate. Materials and Method: An 8-mm, calvarial, critical-size osteotomy defect was created in each of 20 male Sprague-Dawley rats(weight $250{\sim}300g$). The animals were divided into two groups of 10 animals each and allowed to heal for 2 weeks(10 rats). The first group was the control group and the other group was the experimental group which received the novel biodegradable calcium phosphate. Results: The healing of the calvarium in the control group was uneventful. The histologic results showed little bone formation in the control group. The experimental group which received the novel biodegradable calcium phosphate showed a normal wound healing. There were a lot of new bone formation around the biomaterial in 2 weeks. The bone formation increased in 8 weeks when compared to 2 weeks and there was a significant bone increase as well(P<0.01). The nobel biodegradable calcium phosphate showed statistical significance when compared to the control group (P<0.05). The novel biodegradable calcium phosphate in 8 weeks showed a significant increase in bone formation when compared to 2 weeks $(40.4{\pm}1.6)$(%). The biodegradable calcium phosphate which is made from mixing calcium phosphate glass(CPG), NaCO and NaOH solution, is biocompatible, osteoconductive and has a high potency of bone formation. Conclusion: We can conclude that the novel biodegradable calcium phosphate can be used as an efficient bone graft material for its biodegradability and osteoconductivity.

• 한국진공학회지
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• 제7권s1호
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• pp.30-36
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• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• 한국식품영양학회지
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• 제7권3호
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• pp.177-182
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• 1994

The effect of phosphate salt (NafHP04) and sodium citrate on the emulsion stability of soy protein isolate (SPI) in the presence of calcium was investigated in terms of salt concentration and addition order. Both phosphate and citrate salts decreased the solubility of SPI despite their pH enhancing effects. Addition of calcium chloride (CaCl2) significantly decreased ES, which showed nearly negligible at more than 3 mM CaCl2 concentration. When Na2HP04 were added in the presence of 5 mM Cac12, 55 greatly increased up to 20mM concentration, above which however ES decreased. It was found that the addition order of Na2HPO4 and CaCl2 affected ES. The addition of phosphate and subsequent CaCl2 exhibited the higher 55 than the reverse order. In both cases, the overall ES profile was found to be nearly similar to the solubility profile of SPI, indicating the positive relationship between solubility and emulsion stability of SPI in the presence of calcium. Similar trend to the phosphate effect on ES was also observed for sodium citrate in the presence of calcium.

• 한국세라믹학회지
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• 제54권5호
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• pp.395-399
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• 2017

The thermal properties and crystallization behavior of calcium phosphate glass fabricated using eggshell were examined. Nature eggshell has several impurities in the main component of $CaCO_3$. To manufacture calcium phosphate glass, washed eggshell was dissolved in aqua-regia while adding a solution of isopropyl alcohol, D. I. water and phosphoric acid. The calcined precursor was melted at $1000^{\circ}C$, and the glass ($T_g$ : $540^{\circ}C$) was crystallized at $620{\sim}640^{\circ}C$, which temperature range is relatively low compared to the crystallization temperature of other general types of calcium phosphate glass. The calcium phosphate glass using eggshell was successfully crystallized without any additional nucleating agents due to the multiple effects of impurities such as $Fe_2O_3$, $Al_2O_3$, SrO and $SiO_2$ in the eggshell. The main crystalline phase was ${\beta}-Ca(PO_3)_2$ and a biocompatible material, hydroxyapatite, was also observed. The crystallization process was completed under the condition of a holding time of only 1 h at the low temperature.

• 자원리싸이클링
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• 제12권4호
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• pp.38-43
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• 2003

인산염은 유기물의 성장에 필요한 중요한 영양물질이나 아주 미량이 필요하여 폐수 중의 인산염은 오염물질로 작용하며 수생 생태계에 영향을 미친다. 따라서 고농도의 인산염에 대하여 칼슘을 이용한 침전법를 사용하여 인산염의 제거에 관한 연구를 수행하였으며 폐수의 재이용 방면에 대해 고찰하였다. 인산염의 침전 제거 시 pH 조건은 pH 6에서 pH 12로 고려하였는데, pH 12에서 가장 좋은 효율을 나타내었다. 또한 인산염은 침전반응에 의하여 칼슘을 침전반응 당량비의 0.5배 투입한 경우까지 제거율이 급격히 증가하는 경향을 나타내었으며 인산염의 잔존량은 0.0027 mM 까지 낮추는 효과를 가져왔다. 불소가 오염물로 존재하는 상황에서 인산염을 제거하기 위한 실험은 pH 및 농도비에 따라 진행되었으며 pH가 증가할수록 인산염의 제거율은 증가하였다. 또한 인산염 : 불소의 농도비가 증가하여도 인산염의 제거율은 크게 영향을 받지 않은 것이 관찰되었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.130-132
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• 1996

It is well known when porous calcium phosphate ceramics are used as a bone graft substitute, new tissues or blood vessels are grown into the porous implant due to their excellent biocompatibility. In this study, the ${\beta}$-crystalline form of calcium metaphosphate, $Ca(PO_{3})_{2}$ is prepared by the controlled thermolysis of monocalcium phosphate, $Ca(H_{2}PO_{4})_{2}$. The diameter of cylindrical pores formed during cooling was controlled by a holding time at the melting point of a monocalcium phosphate and by the change of a recrystallization temperature, to obtained the most appropriate size (about $200{\mu}m$) of pores. It was observed that the increasing holding time at the melting point of monocalcium phosphate results in the decreases of pore sizes.

• Journal of Nutrition and Health
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• 제28권5호
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• pp.434-441
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• 1995

The model rats with postmenopausal osteoporosis were comparatively observed with regard to the effects of bovine ash and calcium phosphate on calcium metabolism. The modelling design involved the five week-old week-old female SD-strain rats ovariectomized and fed a low-Ca diet(20% casein, 0.06% Ca and 0.38% P) for three weeks. The rats were divided into five groups, one of which was fed the low-Ca diet(basal), and the rest of which were divided into five groups, one of which was fed the low-Ca diet(basal), and the rest of which were fed four kinds of Ca-supplemental diets(20% protein, 1.06% Ca and 0.8% P) for three weeks. The Ca-suplements diets contained two kinds of Ca sources, bovine bone ash(BBA) or calcium phosphate, tribasic [Ca3(PO4)2] and two kinds of protein sources, casein or isolated soy protein(ISP). The model rats of postmenopausal osteoporosis fed basal diet showed a significant decrease in Ca utilization in reference to serum Ca concentration, breaking force of bone, Ca and P contents of bone, and Ca absorption and retention. However, the supply of Ca for three weeks demonstrated the improved utilization of Ca. One step further, BBA was more effective than calcium phosphate in improving Ca utilization in ISP-fed groups. On the other hand, no significant difference was seen in casein-fed groups. It is to conclude that BBA could be more effective in accelerating Ca utilization under vulnerable dietary or physiological conditions such as vegetable protein intake and osteoprosis.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.45.1-45.1
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• 2009

In this study, we investigated a calcium phosphate-calcium sulfate injectable bone substitute (IBS) with organic reinforcement of chitosan, citric acid and hydroxypropyl-methyl-cellulose (HPMC). The powder component of IBS consisted of tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dihydrate (CSD). The liquid component was a solution of citric acid and chitosan. The effect of HPMC in terms of setting time, compressive strength and apatite forming ability on this IBS was investigated. The mass content of HPMC in liquid phase was varied in array of 0%, 2%, 3% and 4%. The setting times obtained between 20 and 45 minutes. Compressive strength was achieved over 20 MPa after incubation at 370C and in 100% humidity for 28 days. Porosities were evaluated in relation with compressive strength. Elastic moduli of the 28 days after-incubation IBS were obtained around 4GPa