• Economic and Environmental Geology
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• v.47 no.5
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• pp.541-549
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• 2014

The annual borate production in Turkey is about 3 million tons, which occupies approximately 61 percent of total annual world production. Turkey has five boron deposits including Bigadic, Emet, Kestelek, Kirka, and Sultancayir. At present, Bigadic, Emet, and Kirka deposits are operating. Kirka boron deposit is distributed within volcanoclatic sedimentary group as mainly layered, rarely brecciated and massive types. Major borate is borax associated with colemanite and ulexite. They show a horizontal symmetrical zonation from Na borate (borax) in the center of deposit to Na-Ca borate (ulexite) and Ca-borate (colemanite) in margin. Bigadic boron deposit is known as the largest colemanite deposit in the world. This deposit occurs as two borate bearing horizons in Miocene volcanoclastic sedimentary group. Thickness ranges from several meters to 100 meter with a length of several hundreds meters. Borate ore bodies which are mainly composed of colemanite and ulexite are alternated with claystone, mudstone, tuff and layered limestone as lenticular shape. Sultancayir boron deposit is mainly distributed within gray limestone. Main borate minerals of this deposit are pandermite and ulexite. Pandermite and ulexite occur as colloform aggregate and small veinlet, respectively. Turkish boron deposits are evaporite deposit which were formed in Miocene playa-lake environment. Boron was supplied to the deposits by the volcanic and hydrothermal activities.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.848-851
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• 2009

석탄슬래그는 회분의 조성에 따라 고온에서 매우 상이한 슬래그 거동을 보여준다. 국내 가스화 대상탄으로 검토된 탄 중, 산성 산화물의 함량이 높아 고용융점을 갖는 7종의 석탄 회분을 가스화 조건인 고온, 환원분위기에서 점도 측정을 실시하였다. 4종의 탄에 대해서는 높은 점도를 낮추기 위하여 염기성 산화물인 CaO를 3가지 비율로 혼합하여 점도 측정을 실시하였다. 또한, flux의 혼합으로 인해 발생할 수 있는 결정체 형성을 FactSage 평형계산 프로그램과 CaO-SiO2-Al2O3 3성분계 상평형도를 이용하여 예측하였다. CaO가 첨가된 시료 모두에서 낮은 CaO 첨가비에서는 원래의 시료보다 낮은 점도를 보였으나, CaO첨가비가 20% 이상일 때는 anorthite이 형성되어 $T_{cv}$를 갖는 결정슬래그로 점도 거동이 변화하면서 실제조업 가능한 온도를 증가시켰다. 점도 측정 후 냉각된 시료의 SEM/EDX 분석을 통해 형성된 결정체를 관찰한 결과, FactSage와 상평형도에서 예측된 결정체와 유사하게 나타나 CaO-SiO2-Al2O3 3성분계 상평형도가 결정체 예측에 유용함을 확인하였다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.142.2-142.2
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• 2012

Hoffmeister(1943)에 의해 변광성으로 발견된 V345 Cas (2MASS J23083986+5406545, ${\alpha}$(2000.0)=23h08m39.86s & ${\delta}(2000.0)=+54^{\circ}06^{\prime}54.6^{\prime\prime}$)는 B 필터에서 13.1~14.2의 광도 변화를 보이는 것으로 알려진 별이다. 우리는 레몬산 천문대(LOAO)에서 2007년과 2008년에 걸쳐 총 22일간 V345 Cas의 BVRI CCD 측광관측을 수행하여, 처음으로 V345 Cas의 년도 별 전체 광도곡선을 완성하였다. 우리의 관측 자료와 Super WASP에서 공개한 자료를 이용하여 각각 7개의 극심시각을 산출하였다. 우리가 결정한 극심시각을 포함하여 여러 문헌에서 수집한 총 68개의 극심시각을 이용하여 V345 Cas의 주기 분석을 수행하였다. 그 결과, V345 Cas의 궤도주기는 포물선 모양의 영년변화와 함께 약 30년의 규칙적인 변화를 겪고 있음을 발견하였다. 규칙적인 변화를 제3천체에 의한 광시간 효과로 가정하여 관측된 극심시각에 잘 맞는 광시간 궤도 해를 산출한 결과, 영년주기가 증가하는 경우와 감소하는 경우에 대해, 각각 29.0년과 39.7년 주기를 갖는 두 개의 광시간 궤도 해가 가능하다. 이러한 모호성을 해결하기 위해서 앞으로의 극심시각 관측이 중요하다. 2007년과 2008년 BVRI 광도곡선들은 부극심을 기준으로 좌우가 거의 대칭이며, 1년 사이에 특기할 만한 광도변화를 보이지 않았다. 우리는 이 광도곡선들을 Wilson-Devinney 쌍성 모델을 이용하여 분석하여, V345 Cas의 측광학적 해를 처음으로 산출하였다. 우리가 구한 해에 의하면, 약 88도의 궤도경사각에 두 성분별의 질량비가 약 0.5인 V345 Cas는 질량과 표면 온도가 큰 주성과 로쉬 로브를 채우고 있는 반성으로 구성된 준 분리형 식쌍성계이다.

• Conservation Science in Museum
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• v.30
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• pp.71-88
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• 2023

This paper examined the visible characteristics and chemical composition of glass beads from the Joseon Dynasty as well as the associations thereof. It also explored the characteristics and uses of glass beads by region. This study covered a total of 1,819 pieces excavated from 25 locations in the Gyeonggi, Chungcheong, and Gyeongsang regions, of which 537 pieces were analyzed for their chemical composition. Glass beads of the Joseon Dynasty take a variety of shapes such as a Round, Coil, Floral, Segmented, Flat, Oval, and Calabash. Colors vary from shades of brown (brown, lemon yellow) and shades of blue (Bluish-Green, greenish-Blue, Purple-Blue) to shades of white (colorless, white) and shades of green (Green, Greenish-Blue, Greenish-Brown). Brown accounts for the largest percentage, followed by Bluish-Green, greenish-Blue. It was identified that Drawing technique was the most common glass bead production technique of the Joseon Dynasty. Potassium oxide (K₂O) was the most common flux agent for glass beads, while the potash glass and mixed alkali glass groups account for the largest quantity. The choice of stabilizers depended on the type of flux agents used, but the most common were calcium oxide (CaO) and aluminum oxide (Al₂O₃). The potash glass and potash lead glass groups are high in CaO and low in Al₂O₃, the mixed alkali glass group is high in CaO, and the lead glass group is low in CaO. In terms of the association between color and shape, most of the beads with shade of brown and blue have round shapes of brown and blue have spherical shapes, while the coil shape is prominent in blue beads. A high percentage of green and colorless beads also take the shape of a coil, while white beads in general have a floral shape. In terms of the association between shape and chemical composition, round, floral and segmented shapes account for a high percentage of the potash glass group, while coil and flat shapes are common in the mixed alkali glass group. This paper also analyzed the colorants for each color based on the association between color and chemical composition. Iron (Fe) was used as the colorant for brown and white, and titanium (Ti) and iron were used for light yellow. Purple-Blue was produced by by cobalt (Co), and greenish-Blue, Bluish-Green, green, Greenish-Blue were produced by iron and copper (Cu). Colorless beads had a generally low colorant content.

• Journal of Energy Engineering
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• v.26 no.1
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• pp.1-8
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• 2017

This study was carried out to physicochemical properties and free CaO contents of coal ash in domestic circulating fludized bed combustion power plant using ethylene glycol method. Results of physicochemical properties, there are many differences in CaO contents for the region position in CFBC plant. The reason, It is considered to be reflected that regulation of exhaust concentration for oxides of sulfur and other operation characteristics of region position in CFBC plant. Free CaO contents are 1.96 ~ 10.78% of fly ash and 0.07~4.24 % of bottom ash, fly ash is higher than in the bottom ash. besides CaO contents of raw materials, particle distribution have a lot of influence Free CaO contents.

• Journal of the Korean Chemical Society
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• v.39 no.7
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• pp.578-584
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• 1995

An aqueous solution of $Ca(OH)_2$ containing a small amount of dissolved $Sr(OH)_2$ was carbonated with $CO_2$ gas, and the effects of the reaction temperature and $Sr(OH)_2$ on the carbonation were investigated. The higher the reaction temperature and the larger the ratio of $Sr(OH)_2(aq)$ to $Ca(OH)_2(aq)$, which amounts to the larger the ratio of $OH^-$ to $CO_2(aq)$, the better pillar aragonite was formed. $Sr(OH)_2$ played an important role in the formation of pillar aragonite, because it is easily formed itself into rhombic $SrCO_3$ during the initial period of carbonation process and acting as a seed for the pillar aragonite of similar morphology. In addition, due to its substantially higher solubility compared with $Ca(OH)_2$, $OH^-$ concentration in the carbonation mixture and subsequently $CO_3^{2-}$ necessary for the crystal growth are increased.

• KSBB Journal
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• v.8 no.2
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• pp.133-142
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• 1993

The effects of genetic and environmental factors on productivity of a cloned protein were studied in recombinant Saccharomyces cerevisiae. Plasmid stability and copy level were very high for a $REP^+$ system(at ca. 10 generations, stability: 65-90%, plasmid copy number per cell: 40-200), whereas these were very low for a yep- system(at ca. 10 generations, stability: 30%, plasmid copy number per cell 20). In plasmids containing the $2{\mu}m$ circle genome, a $[cir^o]$ strain was a preferred host cell since the plasmid stability and the copy number in a $[cir^o]$ strain were higher than in a $[cir^+]$strain. Cloned gene expression was dependent on plasmid copy number and stability. The inducer (galactose) level played a very important role in cloned lacZ gene expression, showing that a galactose concentration of 0.8% was sufficient for induction of gene expression. Induction rate was very fast in the case of plasmids exhibiting high stability and copy number by a factor of 4 to 25. The time to reach the peak value of gene expression was longer when galactose was added at the start of fermentation (ca. 26 hours) than at the mid-exponential phase (ca. 6 hours). Glucose repression was reduced by a factor of 2 to 5 as the relative inducer level increased.

• Asian Journal of Turfgrass Science
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• v.16 no.1
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• pp.1-10
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• 2002

The influence of calcium on the growth of creeping bentgrass 'Penn-Al', perennial ryegrass 'Palmer II', Kentuckuy bluegrass 'Nassou' and tall fescue 'Boonsai 2000' in greenhouse was investigated. Creeping bentgrass 'Penn-A1', Kentucky bluegrass 'Nassou' and tall fescue 'Boonsai 2000' at Ca 4.0 me/L, and perennial ryegrass 'Palmer II' at Ca 2.0 me/L showed the best shoot growth. Creeping bentgrass 'Penn-A1', perennial ryegrass 'Palmer II' and Kentucky bluegrass 'Nassou' at Ca 1.0 me/L, and tall fescue 'Boonsai 2000' at Ca 4.0 me/L showed the best root growth, and there was little or no difference between different Ca concentrations. Creeping bentgrass 'Penn-Al' and Kentucky bluegrass 'Nassou' at Ca 4.0 mea, and perennial ryegrass 'Palmer II' at Ca 1.0 me/L had the highest number of tillers, and tall fescue 'Boonsai 2000' at Ca 4.0 me/L had the highest, but there was no difference between different Ca concentrations. As application rate of Ca concentration became higher, the concent of Ca in plant tissue increased, while the content of Mg in plant tissue decreased, and the content of Fe in plant tissue increased to Ca 4.0 me/L. The Ca treatment had not effect on N, p, K, and Zn of tissue content. The wick pot applied will be to research of plant nutrition in future because utilization of wick pot has an excellent precision and convenience.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.26-30
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• 1994

The purpose of this study was to investigate the effects of heating times of soy protein isolate(SPI) and mixing ratio of coagulants mixture on water holding capacity(WHC) and oil absorption capacity (OAC) of SPI, texture properties and yield of tofu. The effect of heating at $100^{\circ}C$ on the amounts of coagulants required for coagulation showed that the amounts of $CaCl_{2},\;MgCl_{2}$ and GDL decreased as the heating time extended to $6{\sim}9$ minutes while $CaSO_{2}$ was changed little. The tofu yield showed maximum for the tofu prepared by 6 minutes boiling and coagulation with $CaSO_{4}$. The WHC of SPI was significantly reduced by heating at $100^{\circ}C$ while OAC was rather increased until 9 minutes of heating. The textural properties of SPI tofu coagulated with mixed coagulants$(CaSO_{4}-GDL,\;CaSO_{4}-CaCl_{2},\;CaCl_2-GDL)$ showed that softer tofu was obtained as the ratio of $CaSO_{2}$ increased and harder tofu as the ratio of $CaCl_{2}$ and GDL increased. The maximum and minimum tofu yields were prepared from 100% of $CaSO_{2}$ and 100% of GDL, respectively. Organoleptic properties showed that more uniform and tender tofu were obtained with higher portion of $CaSO_{2}$ in the mixed coagulants and higher intensity of sourness and bitterness were scored as the GDL and $CaCl_{2}$ added more.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.180-187
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• 1997

$La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ interconnector films ior pimar rypn solid oxide fuel (,ells were prepared under various sinteririg conditions and their bending strength. relative ilerisit~. m t l c:lec ~ ~ - i i ; i l condl~cti\.lt\ were niexiureti in order to study their mechanical and electrical propertics Th' Irndirig sriength of $La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ lt the room temperature \vas increased with increasing sinrering temperature dnfl tinic. The relative densit\- of more than 94% was ohtained 1)). sintering at $1400^{\circ}C$ for 5hrs. The present irlvestigiition rovcals thcit sirileririg of $La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ at lorn. temperature xyvas greatly assisted by formation oi Ca,,,(CrO,),, Also the i,leitriczl conductivity at $1000^{\circ}C$ \vas more than 100S; cm d t e r heating at $1400^{\circ}C$ for 7hrs.