• The Korean Journal of Ceramics
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• 제5권3호
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• pp.260-264
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• 1999

Effect of the particle size of $MgTiO_3$ and $CaTiO_3$ on the microstructural evolution during sintering of $0.93MgTiO_3-0.07CaTiO_3$ system was investigated. Microwave dielectric characteristics of the sintered ceramics were also measured. The microstructural evolutions were explained with an emphasis on the entrapping behavior of $CaTiO_3$ grain into the $MgTiO_3$ grain and were correlated with microwave dielectric characteristics. With an increasing particle size ratio between $CaTiO_3$and $MgTiO_3$, the fraction of entraped $CaTiO_3$ grains increased, which grain growth of $MgTiO_3$were concurrently accelerated due to decreasing drag force of its boundary migration. Besides, $CaTiO_3$-grain entrapment into the $MgTiO_3$grain interior led to decreaseing quality factor values.

• 한국세라믹학회지
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• 제40권11호
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• pp.1132-1137
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• 2003

환경친화적인 유리비료로서의 응용을 위해 인산염계 유리의 용출특성에 대한 연구를 진행하였다. 0.1K₂O-0.1SiO₂-0.6P₂O/sub 5/계 유리를 기본조성으로 하고, CaO와 MgO의 함량변화를 준 다양한 유리조성에 대한 유리 형성 조건을 확인하고자 하였다. 또한 CaO 및 MgO의 함량변화에 따른 열적특성 및 용출 특성 변화를 확인하였다. MgO 함량의 증가에 따라 유리 전이온도 및 연화온도는 증가하였으며, CaO 및 MgO의 함량변화에 따라 용출특성에 큰 영향을 미치는 것을 확인하였다.

• 자원리싸이클링
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• 제24권1호
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• pp.35-42
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• 2015

본 연구는 건식제련법으로 폐 PCB를 처리하는 공정에서 슬래그 중 Ni의 용해거동에 대한 기초연구로서, CaO-$SiO_2-Al_2O_3$-MgO계 슬래그와 Cu-5 wt%Ni합금 사이의 Ni 분배거동을 1623~1823 K의 $CO_2$-CO 분위기 중에서 조사하였다. 평형산소분압이 증가할수록 Ni의 분배비는 선형적으로 증가하였으며, 이 결과로부터 Ni의 슬래그 중 용해반응은 다음과 같이 나타낼 수 있다. $$Ni(l)_{metal}+\frac{1}{2}O_2(g)NiO(l)_{slag}$$ 슬래그 중 염기성 산화물(CaO와 MgO)의 농도가 증가할수록 Ni의 분배비는 선형적으로 증가하였다. 그러나 반응 온도가 높을수록 Ni의 분배비는 선형적으로 감소하였다. 이러한 결과로부터 Ni의 분배비에 미치는 실험변수의 영향을 다중 회귀분석하여 다음과 같은 경험식을 얻었다. $${\log}L_{Ni}=0.4000{\log}P_{O2}-5.1{\times}10^{-4}T+0.3375\(\frac{X_{CaO}+X_{MgO}}{X_{SiO2}}\)$$

• 자원리싸이클링
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• 제20권3호
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• pp.55-61
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• 2011

금속급 실리콘(MG-Si)을 태양전지용 실리콘(SOG-Si)으로 정제하기 위한 경제적인 프로세스를 구축하기 위하여 1823 K에서 CaO-$SiO_2$ 계 슬래그에 의한 붕소의 제거에 대하여 조사하였다. 본 연구에서 CaO-$SiO_2$와 $CaCO_3-SiO_2$ 슬래그의 염기도(%CaO/$%SiO_2$) 증가에 따라 B의 제거율은 각각 63%와 73%까지 증가하였다. 그러나 Ar 가스에 의한 슬래그와 실리콘의 교반 시간의 영향은 나타나지 않았다. 그리고 CaO-$SiO_2$ 계 슬래그에 $Na_2CO_3$를 첨가하였으나 그 영향은 크지 않았다. $CaCO_3-SiO_2$ 슬래그(염기도=1.2)에 의해 3회 처리한 결과 B의 농도는 1.03 ppm까지 감소하였다.

• 대한수의학회지
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• 제29권3호
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• pp.263-274
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• 1989

The present study was conducted ill. order to get the normal blood chemical values of Korean Jindo dogs. Blood samples were taken from 160(♂34, ♀126) healthy Jindo dogs in Jindo area. The results obtained in this study were summarized as follows: 1. The mean values of serum total protein(TP), albumin(Alb) and globulin(Glb) content, cholesterol(Chole), magnesium(Mg), calcium(Ca), inorganic phosphate(P), potassium(K), sodium(Na) and chloride(Cl) concentration in the group of less than one year old were 6.64(♂6.62, ♀6.64), 3.63(♂3.57, ♀3.65) and 3.00(♂3.05, ♀2.99)g/100ml, 170.97(♂166.46, ♀172.68)mg/100ml, 1.45(♂1.43, ♀1.46), 5.76(♂5.62, ♀5.81), 4.80(♂4.95, ♀4.75), 4.84(♂4.72, ♀4.89), 148.93(♂148.79, ♀148.98) and 110.22(♂110.42, ♀110.14)mEq/L, respectively, whereas the TP, Alb and Glb content, Chole Mg, Ca, P, K, Na and Cl concentration in the group of one year old and more were 6.88(♂6.84, ♀6.89), 3.65(♂3.63, ♀3.66) and 3.23(♂3.21, ♀3.23)g/100ml, 167.48(♂173.80, ♀166.48)mg/100ml, 1.40(♂1.36, ♀1.40), 5.69(♂5.53, ♀5.71), 4.62(♂4.73, ♀4.60), 4.88(♂4.90, ♀4.87), 149.86(♂149.60, ♀149.90) and 110.03(♂110.70, ♀109.92)mEq/L, respectively. The ratios of mean serum albumin to globulin(A/G), calcium to inorganic phosphate(Ca/P) and sodium to potassium(Na/K) in the group of less than one year old were 1.21(♂1.17, ♀1.22), 1.20(♂1.14, ♀1.22) and 30.77(♂31.52, ♀30.47), respectively, whereas the A/G, Ca/P and Na/K in the group of one year old and more were 1.13(♂1.13, ♀1.13), 1.23(♂1.17, ♀1.24) and 30.71(♂30.53, ♀30.78), respectively. 2. The mean values of Alb content, Mg, Ca and K concentration, A/G and Ca/P ratio appeared to be higher in the female than in the male, whereas the reverse was the case with P concentration. No differences were found between male and female in the TP and Glb content, Chole, Na and Cl concentration and Na/K ratio. 3. The mean values of Glb content appeared to be higher in the group less than one year old than in the group of one year old and more, whereas the reverse was the case with A/G ratio. The mean values of TP and Alb content and Ca/P ratio in the age groups less than one year tended to increase with aging, whereas the reverse was the case with Ca and P concentration. No differences were found between age groups in the Mg, K, Na and Cl concentration and Na/K ratio.

• 한국세라믹학회지
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• 제21권3호
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• pp.221-230
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• 1984

In this study an investigation was made to determine optimum ratio between $SO_3$, MgO and $K_2O$ that maximizes $C_2S$ formation in Clinkering reaction Using response surface analysis method. It was proved that 1) Residual $K_2O$ int he clinker should be converted to $K_2SO_4$ because $K_2SO_4$ has less effect on the burnability than $K_2O$, 2) Optimum ratio if $SO_3$/K2O is 1.5, 3) Optimun balance between $CaSO_4$ and MgO is to be adjusted to such a level that w/o SO3=0.7(w/o MgO-2).4) In case of lack of $K_2O$ free CaO was minimized when $K_2SO_4$=2.3w/o and MgO=1.5w/o but if remaining $K_2O$ was 2w/o free CaI was minimized in the level that $K_2SO_4$=2.3w/o and MgO =1.5 w/o but if remaining $K_2O$ was 2 w/o free CaO was minimized in the level that $K_2SO_4$=4.5w/o and MgO =3.0 w/o.

• Journal of Nutrition and Health
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• 제32권6호
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• pp.661-670
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• 1999

Effects of Ca supplementation on blood pressure(BP) response to dietary Na level were studied in 15 normotensive healthy college women with family history of hypertension. All subjects, randomly divided into 3 groups, ate low Na diet(1816mg/day) prepared in the laboratory during the first 2 weeks and normal Na diet(4064mg/day) of their own home for the next 8 weeks. The one group received daily 1g Ca supplement at both low and normal Na diet periods, the second group took daily 1g Ca supplement only at normal a diet period, and the last group took placebo during both periods. Average Ca and energy intakes at the basal of and during the trial ranged 450-600mg and 1735-1878kcal, respectively. Systolic/diastolic BP was decreased by 9.2-9.8/4.4-4.5 mmHg during low Na diet period and was increased again during next normal Na diet period. However simultaneous Ca supplementation during both low and normal Na diet period suppressed the elevation of systolic/diastolic BP occurred at normal Na diet period. Ca supplementation only at normal Na diet peroid did not affect the BP elevation. The increase of serum Ca and Ca/Mg ratio and the decrease of serum Na and Na/K ratio might be related to the BP lowering effects of Ca supplementation. In conclusion, Ca supplement could attenuate BP elevation induced by increasing Na intake. The BP lowering effect of Ca supplementation was not appeared at low Na intake. Further studies were needed to make it certain. Low Na intake was also confirmed as an effective diet control for lowering blood pressure.

• 한국결정성장학회지
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• 제2권2호
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• pp.20-32
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• 1992

$Na_2O-CaO-MgO-Al_2O_3-SiO_2$계를 기본조성으로 하여 $Na_2O$에 $Li_2O 0.05wt%, $K_2O$를, CaO에 MgO 12.0wt%, ZnO 6.0%를 각각 치환하여 조성을 선정하였다. 기본 유리조성의 결정상은 wollastonite이고, 치환된 조성들은 diopside, diopside.tremolite의 혼정이 나타났다. $Na_2O$를 $Li_2O$로 치환한 시편은 열팽창계수가 감소하였지만 CaO를 ZnO로 치환한 시편은 열팽창 계수가 증가하였다. 곡강도에 있어서는 치환에 따라 모두 증가시켰다. 핵행성제로 $ZrO_2와 $CaF_2$를 각각 1~2wt%의 변화를 시켜본 결과 핵형성제 $ZnO_2$와 $CaF_2$가 1:1, 1:2인 시편은 $1000~1050^{\circ}C$온도에서 급격한 결정성장을 보였으며 1:2시편이 가장 낮은 열팽창 계수값을 나타냈다. 곡강도는 모두 $1000~1050^{\circ}C$의 결정화 온도 범위에서 높은 강도를 나타내었다. 결정화에 필요한 활성화 에너지는 Ozawa와 Kissinger식으로 plot하여 각각 55.24kcal/mol과 53.05kcal/mol이다.

• 공업화학
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• 제34권2호
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• pp.111-120
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• 2023

이산화탄소 순환 물질 중 대표적인 광물인 탄산칼슘의 형성 과정을 관찰하고, 대표적 조절 변수인 마그네슘-칼슘 이온의 혼합 비율(Mg/Ca 비)과 온도가 pre-nucleation cluster (PNC) 및 탄산칼슘 형성에 미치는 영향을 분석하고자 실험과정에서 칼슘 이온 선택성 전극(calcium ion selective electrode, Ca ISE)을 이용하여 핵형성 과정을 연구하였다. 실험결과 미량의 결정이 형성되었으며 표면 원소 분석을 위해 에너지 분산 X선 분석법(energy dispersive X-ray spectroscopy, EDS)을 사용하였고, 형상 분석을 위해 주사 전자 현미경(field emission scanning electron microscope, FE-SEM)을 사용하였다. Mg/Ca 비와 온도 조건에 따라 다양한 형상의 결정질 탄산칼슘(방해석, 아라고나이트 등)을 확인하였으며 Ca ISE로부터 얻은 칼슘 이온 농도 그래프는 탄산칼슘 형성 과정을 보여주었다. 칼슘 이온 농도 그래프 분석을 통해 마그네슘 이온은 칼슘 이온과 탄산 이온의 결합을 방해하고 PNC 간 응집을 지연시켜 핵형성 및 탄산칼슘의 형성을 지연시킴을 확인하였다. 반면 온도는 이와 반대되는 효과를 보였으며, 본 실험 조건에서는 마그네슘 이온보다 더 큰 영향을 미쳤다. 또한 Mg/Ca 비와 온도에 따라 탄산칼슘의 형상이 뚜렷하게 변화하여 두 인자는 탄산칼슘 형성 과정에 전반적으로 영향을 미치는 중요 조절 변수임을 확인하였다.

• Nutritional Sciences
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• 제2권2호
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• pp.82-87
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• 1999

Zinc nutriture in South Koreans was evaluated by estimating Zn, Ca, and phytate intake, and the molar ratios of phytate : Zn and the millimolar ratios of phytate $\times$ Ca Zn. food consumption data from the 95 National Nutrition Survey was used. For the present study, data from the nationwide, large city and urban area level were used. No standard deviation measures were provided in the 95 National Nutrition Survey : only mean values were reported. Nationwide daily intake of Zn and Ca were 10.1 mg/day and 426.5 mg/day, respectively. The estimated daily phytate intake was 1676.6 mg/day nationwide. The molar ratio of phvtate : Zn, the millimolar ratio of phytate $\times$ Ca : Zn and the phytate $\times$ Ca Zn mmol per 4.2 MJ (1000 kcal) were 15.9, 168.9 and 91.8 in nationwide, respectively. The major food groups for zinc intake were meat, poultry products (43%), and cereals and grain products (18%). Sixty two percent of Zinc was from animal food sources. Cereal and grain products supplied most of the phytate intake (46%), followed by seasonings, fruits, and legume products. The major food source of phytate was rice (39%) . The results of the present study suggest that Zn status of Koreans maybe influenced by high dietary intake of phytate and high molar ratios of phytate : Zn and phytate $\times$ Ca : Zn. These results raise concerns about Zn status of Koreans, who consume a diet higher in phytate than Western diets. further research is necessary to confirm whether such poorly available dietary Zn has any impact on the health of Koreans.