• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.24-25
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• 2017

Gamma-C₂S (γ-C₂S) is a substance that is difficult to react with water under normal temperature but can absorb a large amount of CO₂ in the air. The addition of γ-C₂S to cementitious materials through the curing of CO₂ can improve the pore structure and improve the durability of the material. In this study, three kind of Ca-bearing materials : CaO, Ca(OH)₂, CaCO₃, were calcined 2.5h at 1450℃ to synthesize γ-C₂S after mixing with SiO₂ respectively. Among them, Ca(OH)₂ mixed with SiO₂ after calcining shows highest content. Synthesized γ-C₂S was added to the cement mortar, after water curing for 1 month, accelerated carbonation test was experimented. After 28d accelerated carbonation test, pore structure will be detectived by MIP. Based on the MIP result, following the calculation method of Fractal theory, the pore structure will be quantitative described.

• Journal of Korea Foundry Society
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• v.28 no.5
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• pp.221-225
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• 2008

The structural and hardness variations of Mg-5Sn-(1,2,3) Ca (wt%) alloys have been investigated during various aging heat treatments followed by solution heat treatment at $500^{\circ}C$ for 24 hrs. Maximum hardness of Hv61 has been obtained for Mg-5Sn-3Ca alloys, when the aging treatment was performed at $200^{\circ}C$ for 24 hrs. The microstructures were critically changed when the content of Ca was more than 1wt%, since CaMgSn and $Mg_{2}Ca$ phases were mainly precipitated during aging treatments. The hardness variations with structural evolutions are discussed with respect to the aging temperatures and times.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.689-695
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• 1991

Dielectric properties of Ba1-$\chi$Sr$\chi$Ti1-yCayO3-y ceramics, where Sr and Ca were doped to Ba-site and Ti-site within the range of 0 x 0.24 and 0 y 0.05, respectively, were investigated. The substitution of Ca for Ti, which maintained the high resistivity of these formulations after sintering in a reducing atmosphere, was confirmed. Ca addition decreased the tetragonality c/a, increased the unit cell volume, and lowered Curie temperature, which were attributed to the occupancy of Ca2+ ions on Ti-sites. The lowering of Curie temperature by Ca addition was affected by the substitution of Sr for Ba-site; within 2 mol% of Ca, Curie temperature was lowered at a rate of 2$0^{\circ}C$ and 16$^{\circ}C$ per mol% of Ca at x=0 and x=0.08, respectively. Whereas the resistivity of the formulations without Ca was reduced to 107 {{{{ OMEGA }}cm, when sintered at low oxygen partial pressure of 10-9 MPa, the resistivity value higher than 1011 {{{{ OMEGA }}cm was maintained for the formulations containing Ca more than 0.5 mol%. Dielectric loss factor, tan$\delta$, was about 1% for most formulations.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.304-309
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• 1997

Chemical compositions of petals of Chrysanthemum spp. were determined to renew its interest as a food material. The moisture contents of wild Chrysanthemum boreale and holticulturized Chrysanthemum morifolium were 11.7% and 11.0%. The proximate chemical ompositions were 6.1% and 11.7% in protein, 3.7% and 5.2% in ash, 11.1% and 12.8% in reducing sugar, of C. boreale and C. morifolium, respectively. Free sugars were mainly composed of fructose, glucose and sucrose. In fatty acid composition, the ratios of saturated to unsaturated fatty acids were 1.2:1 and 3.0:1, respectively. The amino acids determined were found 0.18 and 0.26 in the ratio of essential to total amino acids in each sample. Major elements of Chrysanthemum petals were Ca, K, Fe, Mg and Na, but the contents of Ca and Fe were more than twice higher in C. boreale than c. morifolium, Major volatile flavor components were 28.22% of epi-bicyclophellandrene and 24.55% of camphor in C. boreale, and 14.24% of 4-methyl-1-(10methylethyl)-3-cyclhexen-1-ol, 10.74% of camphor and 7.64% of 1,8-cineol in C. morifolium.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.336-343
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• 1996

Maximum amount of the aminopeptidase M inhibitors produced by Streptomyces griseoplanus SL20209 in 500 ml-Erlenmeyer flask was accumulated after cultivation for 3 days at 28$\circ$C, thereafter the amount of inhibitors decreased slowly with a pH change to alkaline. Arabinose, xylose, mannose and soluble starch were good carbon sources for the production of the inhibitors. On the other hand, glucose was only good for the cell growth but potently inhibited the production of inhibitors. Natural organic nitrogen sources such as soybean meal, fish meal, gluten meal and peanut powder were good for the production of inhibitors, however, soytone, peptone and inorganic nitrogens such as NH$_{4}$C1 and NH$_{4}$NO$_{3}$ were poor. Inclusion of yeast extract (0.5%, w/v) or K$_{2}$HPO$_{4}$ (0.05%) into the production medium increased the production of inhibitors by accelerating cell growth. The production of inhibitors was slightly increased on the medium containing CaCO$_{3}$ (0.3%) and zeolite (0.5%), respectively. Optimal temperature and initial pH range for the production ot inhibitors were determined to be 28$\circ$C and 6.0-7.0, respectively. Employing two improved production media consisting of 3% arabinose or soluble starch, 2.5% soybean meal, 0.5% yeast extract, 0.05% K$_{2}$HP0$_{4}$, 0.1% CaCO$_{3}$ and 0.3% zeolite (pH 6.8), 1.8-fold increase in the amount of inhibitors was achieved, comparing with the basal medium used.

• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.24-28
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• 2018

To understand the effects of Cd substitution for Cu, $(Pb_{0.5}Cu_{0.5-x}Cd_x)Sr_2(Ca_{0.7}Y_{0.3})Cu_2O_z$ (x = 0 ~ 0.5) compounds were synthesized and the structural and superconducting properties of the compounds were characterized. Resistivity data revealed that superconducting transition temperature rises initially up to x = 0.25 and then decreases as the Cd doping content increases. Room-temperature thermoelectric power decreases at first up to x = 0.25 and then increases with higher Cd doping content, indicating that the change in $T_c$ is mainly caused by the change in the hole concentration on the superconducting planes by the Cd doping. The non-monotonic dependence of the lattice parameters and the transition temperature with Cd doping content is discussed in connection with the possible formation of $Pb^{+2}$ ions and the removal of excess oxygen caused by Cd substitution in the charge reservoir layer. A correlation between transition temperature and c/a lattice parameter ratio was observed for the $(Pb_{0.5}Cu_{0.5-x}Cd_x)Sr_2(Ca_{0.7}Y_{0.3})Cu_2O_z$ system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.45-49
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• 2002

This study was conducted to enhance the value of chamnamul (Pimpinella brachycarpa (Komarov) $N_{AKAI}$) as an useful food resource. Hunter L, a, b values (lightness, redness, yellowness) of chamnamul leaf were 33.28$\pm$1.94, -10.98$\pm$0.74, 14.05$\pm$1.29 and shearing force was 2745.2g. Contents of tannin and dietary fiber were 100.9 mg%, 24.0% (freeze drying base). The minerals identified in chamnamul were Ca 7.85 g/kg, K 76.31 g/kg, Mg 4.78g/kg, Fe 0.35g/kg, Na 2.35 g/kg. Chamnamul kimchi was packed in polyethylene film (200g) and fermented at 2$0^{\circ}C$ and 4$^{\circ}C$. In color changes kimchi fermented at 2$0^{\circ}C$ showed more increase in Hunter L, a, b values than kimchi fermented at 4$^{\circ}C$. The pH of kimchi decreased and acidity increased with storage time at both temperature. Ascorbic acid contents decreased sharply with storage time. Loss of ascorbic acid contents was about 81.9% in kimchi fermented at 2$0^{\circ}C$ after 5 days, and kimchi fermented 4$^{\circ}C$ lost 77.3% of ascorbic acid after 30 days. Also reducing sugar contents decreased with storage time at 2$0^{\circ}C$ and 4$^{\circ}C$. The results of sensory evaluation showed that optimum ripening time of chamnamul kimchi was 1~3 days at 2$0^{\circ}C$ and more than 20 days at 4$^{\circ}C$.>.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.165-165
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• 2013

희토류 발광 물질은 4f 껍질에 위치하는 전자의 독특한 특성 때문에 발광 소자와 디스플레이에 그 응용성을 확장하고 있다. 본 연구에서는 고효율의 적색과 주황색 형광체를 합성하기 위하여 모체 격자 CaNb2O6에 희토류 이온인 유로퓸과 사마륨을 치환 고용하여 최적의 합성 조건을 조사하였다. Ca1-1.5xNb2O6:REx3+ (RE=Eu, Sm) 형광체 분말 시료는 고상반응법을 사용하여 활성제 이온인 Eu3+와 Sm3+의 농도비를 0, 0.01, 0.05, 0.10, 0.15, 0.20 mol 로 변화시키면서 합성하였다. 초기 물질 CaO, Nb2O5, Eu2O3와 Sm2O3을 화학 적량으로 측정하고, 400 rpm의 속도로 24시간 밀링 작업을 수행한 후에, 건조기 $60^{\circ}C$에서 28시간 건조하고, 시료를 막자 사발에서 갈아 세라믹 도가니에 담아 튜브형 전기로에서 분당 $5^{\circ}C$의 비율로 승온시켜 $500^{\circ}C$에서 5시간 동안 하소와 $1,100^{\circ}C$에서 6시간 소결하여 합성하였다. Eu3+가 도핑된 경우에, 발광 스펙트럼은 Eu3+ 이온의 농도비에 관계없이 강한 적색 발광 스펙트럼이 616 nm에서 관측되었다. 이외에도, 596 nm와 708 nm에서 상대적으로 발광 세기가 약한 주황색 발광과 적색 발광 신호가 검출되었으며, 541 nm에서는 매우 약한 녹색스펙트럼이 관측되었다. Eu3+ 이온의 농도비에 0.01 mol에서 0.15 mol로 증가함에 따라 주발광 신호의 세기는 점점 증가하였으며, 0.15 mol에서 최대 발광 세기를 나타내었다. Eu3+ 이온의 농도비가 0.20 mol 로 더욱 증가함에 따라 주 피크의 세기는 농도 소강 현상에 의하여 현저히 감소함을 보였다. 한편, 주된 흡광 스펙트럼은 279 nm에서 나타났는데, 이것은 전하전달밴드 신호이다. Sm3+가 도핑된 형광체 분말의 발광 스펙트럼은 모든 시료의 경우에 613 nm에서 강한 적주황색 발광 스펙트럼이 관측되었고, 상대적으로 세기가 약한 570 nm와 660 nm에 피크를 갖는 황색과 적색 발광 스펙트럼이 발생하였다. 흡광과 발광 스펙트럼의 최대 세기는 0.05 mol에서 나타났으며, Sm3+ 이온의 농도비가 더욱 증가함에 따라 흡광과 발광 세기는 급격하게 감소하였다.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.282-288
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• 1996

Because of the high water content of the household garbage, it is difficult to compost it. Therefore, this study was conducted to investigate the possibility of using coal fly ash as humidity conditioner for the household garbage composting. The summarized results are as follows : 1. The maximum temperatures were $35^{\circ}C$ in spring, $47^{\circ}C$ in summer, and $43^{\circ}C$ in winter during the composting periods. 2. The mass was reduced to 70.5% after 60 days. The average volume reduced down to 74.7% after 60 days. 3. The seasonal variation of pH values showed a similar tendency and reached 8.5 after 60 days. 4. The water content was reduced at an early stage of composting and not much changed thereafter. It had 49.7% in spring, 33.9% in summer, and 56.5% in winter after 60 days. Ash contents were not much changed during the composting periods. 5. The contents of inorganic compounds were in the range of $0.06{\sim}4.03%$ $P_2O_5$, $0.01{\sim}2.87%$ CaO, $0.18{\sim}1.43%$ MgO, and $0.39{\sim}2.03%$ $K_2O$. Heavy metal contents were in the range of $ND{\sim}14.08$ Hg ${\mu}g/kg$, $ND{\sim}0.80$ Cd mg/kg, $4.99{\sim}28.95$ Cu mg/kg, $ND{\sim}242.62$ Cr mg/kg, $ND{\sim}20.24$ Pb mg/kg, and $ND{\sim}59.87$ Zn mg/kg.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.737-748
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• 1995

Osteoblast(OBL) cells were isolated from ICR Swiss neonatal mouse calvarial tissues and cultured in a CO2 incubator with minimum essential medium (MEM) containing 0.25g BSA. The cells were cultured for 7 days and were treated with bovine parathyroid hormone (bPTH, 1-34) and calcitonin(CT). Enzyme activities related to mineral metabolism and other biochemical actions within the bone cells including protein phosphorylation were investigated. In other experiments using cultured calvarial bone tissues, hormones were treated for 24, 48, 72 or 96 hours. The activities of $\beta$-glucuronidase enzymes involved in bone collagen synthesis and mineral deposits were increased by 8% with bPTH and were inhibited with CT treatment, while those were 67% increase treated with bPTH and CT together. On the other hand, alkaline phophatase(AP) activities were inhibited by PTH hormone at all the time courses observed. Protein phosphorylation reaction in OBL was mediated by bPTH, cAMP and ionized Ca. Phosphorylation was observed in different cell fractions including homogenate, membrane and cytosol. The number of proteins phosphorylated by PTH, cAMP, and Ca were 10, 5, and 9, respectively. Most of the protein kinases(PKs) were existed in cytosolic compartment. In membrane fractions, two bPTH-dependent-PKs (70K, 50K Da) were observed of which 70K Da protein was also Ca-dependent. Most of the cAMP-dependent PKs were regulated via bPTH. 70K, 50K, 5K, 19K, 16K, 10.5K phosphoproteins regulated by Ca share the same pathways as those by bPTH-dependent proteins. Ca seems to regulate PK activities differently from cAMP.