• 한국세라믹학회지
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• 제44권9호
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• pp.529-535
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• 2007

Calcium oxide has been used as a demolition agent in fracturing rocks and old concrete structures, etc. With the agent, demolition work can be done in safety without a noise, vibration and any other pollution, since high expansive pressure is obtained gradually by only mixing the agents with water and pouring the slurry into boreholes. But application of the non-explosive demolition agent is a time-consuming job, especially in winter. Essentially, this problem is related to the reaction rate of calcium oxide with water. This study examines the influence of additives such as cement and anhydrite on expansion pressure of calcium oxide at different curing temperatures. The expansion pressure of calcium oxide began to increase steadily with the rise of the curing temperature. When mixing calcium oxide alone with water, blown-out shot occurred. But as additives were added to calcium oxide, the reaction of calcium oxide delayed and the expansion pressure showed gradual increment. Especially, anhydrite showed a superior delaying effect than cement on the reaction of calcium oxide.

• 대한치과보철학회지
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• 제15권1호
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• pp.43-47
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• 1977

The purpose of this study was to determine human pulp reactions to temporary cements such as zinc oxide-eugenol cement, modified zinc oxide-eugenol cement (Cavitec) and calcium hydroxide cement (Dycal). Deep class V cavities were prepared in the human teeth with ultrahigh-speed handpiece operating at a free running speed of 300,000 r.p.m., using # 701 bur and water spray coolant. The cavities were flushed with water, dried with cotton pellets and filled with zinc oxide-eugenol cement, modified zinc oxide-eugenol cement and calcium hydroxide cement respectively. The teeth were divided into two groups, which one group was extracted after One day and the other was extracted after seven days. The samples were examined with microscope and the findings were as follows; 1. The pulp reactions to temporary cements were generally mild. Among them the reactions were moderate in zinc oxide-eugenol cement and, slight in calcium hydroxide cement. 2. Calcium hydroxide cement may be used properly as temporary cement for the purpose of pulp protection.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.272-288
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• 2000

수산화칼슘은 여러 약리작용으로 인해 근관소독제로 널리 사용되고 있는 약제이다. 근관 내에 수산화칼슘을 투약한 후 gutta-percha와 더불어 산화아연-유지놀계 근관시멘트로 근관을 충전하는 경우 근관시멘트의 물성에 변화가 있다는 보고가 있다. 따라서 본 연구에서는 수산화칼슘과 산화아연-유지놀 간의 반응에 의해 생성되는 수산화칼슘-유지놀 화합물의 반응성을 확인하기 위하여 수산화칼슘, 유지놀, 산화아연-유지놀, 수산화칼슘-유지놀 및 수산화칼슘-산화아연-유지놀 화합물을 XRD, FT-IR spectrophotometer 및 FT-NMR spectrometer로 분석하여 다음과 같은 결과를 얻었다. 1. 수산화칼슘과 산화아연-유지놀 간의 반응으로 생성된 화합물은 다음과 같았다. 2. 수산화칼슘은 유지놀과 화학결합(이온결합)을 하는 것으로 나타났다. 3. $Ca^{2+}$과 유지놀 사이의 결합은 단순 이온결합이다. 따라서 수산화칼슘-산화아연유지놀 화합물은 중화반응에서 생기거나 외부에서 유입된 물이 존재시 쉽게 이온화되어 물리적 성질이 저하될 것으로 생각된다.

• 원예과학기술지
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• 제28권6호
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• pp.1072-1077
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• 2010

본 실험은 7가지의 칼슘제제; calcium sulfate dihydrate, calcium chloride, calcium nitrate, calcium oxide, calcium hydroxide, calcium carbonate, calcium hydride가 포함된 PDA배지에서 잿빛곰팡이 균의 방제효과를 알고자 실시되었다. 선발된 칼슘제제의 pH는 8.2-10으로 대조구인 pH 6.6보다는 높게 측정되었다. 7가지 칼슘제제가 포함된 PDA배지에서의 잿빛곰팡이병 방제 colony size(mm) 결과는 calcium carbonate, calcium oxide, calcium hydride, calcium hydroxide가 다른 칼슘제제들 보다 잿빛곰팡이병 억제에 효과가 좋았다. 선택된 4개의 칼슘제제를 식물체에 처리 한 후 잿빛곰팡이병의 포자를 살포한 실험과 희석된 4개의 칼슘제제)를 표준 양액재배에 첨부하여 한 달간 양액을 공급한 후 잿빛곰팡이병의 포자를 접종한 실험결과는 칼슘제제를 처리하지 않은 대조구보다는 칼슘제제를 처리한 실험구에서 잿빛곰팡이병의 발생률이 대체적으로 낮았다. 칼슘제제를 처리한 파프리카 식물체에서 잿빛곰팡이병 억제에 대하여서는 칼슘제제 처리에 따른 어느 정도의 염기스트레스의 영향 등으로 볼 수가 있겠다.

• 한국수산과학회지
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• 제47권5호
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• pp.567-576
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• 2014

This study investigated the physiological effects of a diet containing calcium oxide (CaO) on the olive flounder, Paralichthys olivaceus. The results indicate that the amount of calcium in the blood was higher in the calcium group compared with the controls. The aspartate amino transferase (AST) and alanine amino transferase (ALT) levels were lower in the calcium group, while lysozyme activity was higher in the calcium group. Histologically, fish in the calcium group had more hepatocytes in the liver and more intact scales. In addition, an attack experiment using Vibrio anguillarum (KCTC-2711) and Edwardsiella tarda (KCTC-3657) showed that the survival was higher in the calcium group compared with the controls. These results suggest that feeding fish CaO when they require it, such as during periods of gonadal maturation and rapid growth, will increase their immunity and resistance to pathogens.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.297-298
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• 2006

Free-machining agent 'KSX' contains complex calcium oxide is developed. The effect of admix ratio of KSX on mechanical properties and machinability with two different cutting speeds is reported. KSX displays improved machinability without deterioration of mechanical properties up to 0.3mass% addition. It was observed that KSX is effective with a small addition of 0.1mass% at slower cutting speed, and increased of admix ratio is effective at faster cutting speed.

• The Korean Journal of Physiology
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• 제26권2호
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• pp.123-128
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• 1992

The present study was undertaken to examine if endogenous nitric oxide is partly responsible for the high calcium induced vasorelaxation in vitro. Isolated porcine coronary arterial rings were suspended in the tissue chamber and their changes in isometric tension were recorded. KCI little affected the vascular tension in the calcium free media, but subsequent addition of cumulative doses of $CaCl_3$ from 1 to 40 mM caused a contraction followed by complete relaxation. The maximum tension was noted at the calcium concentration in the media of 5 mM, and then the tension progressively declined at 10-40 mM. The relaxation was slightly attenuated in the endothelium-denuded preparation. The relaxation was converted into a contraction by the addition of methylene blue. The relaxation response was not affected in the presence of indomethacin, but was significantly attenuated by $N^w-nitro-L-arginine$ methyl ester pretreatment. These results suggest that the calcium induced vasorelaxation is in part attributable to the release of endogenous nitric oxide.

• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.27-35
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• 1980

This study was to evaluate the effectiveness of a few disinfectant on amputated pulps of domestic dogs. The materials employed for the purpose were zinc oxide eugenol paste, calcium hydroxide as control groups and guaiacol (1%, 5%, 10% by weight) added zinc oxide eugenol paste and formaldehyde (1%, 5%, 10% by weight) added calcium hydroxide as experimental groups. Following were the results obtained throngh histo-pathological examination. 1) In calcium hydroxide-formaldehyde groups, secondary dentin formation was observed in the 2 weeks, but the remaining pulp tissue was severely atrophied according to the concentration of formaldehyde and the time increased. 2) In zinc oxide eugenol-guaiacol groups, the first evidence of secondary dentin formation was observed in the 3 weeks. It seems that the concentration variety of guaiacol influenced very little to the potential ability of dentin formation. 3) Except 1% formaldehyde containing calcium hydroxide group, every group showed severe pulp degeneration. In all groups of zinc oxide eugenol-guaiacol cases revealed the tendency of recovery.

• 생명과학회지
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• 제17권12호
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• pp.1701-1708
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• 2007

펠렛의 목적은 기계화 정밀파종하여 파종과 솎음노력을 절감하는데 있다. 펠렛 피복물질의 용적밀도는 dialite, kaolin 및 talc 등이 낮았고 기공성은 높았다 보수력이 우수한 피복물질은 bentonite와 dialite 이었으며, 184% 및 173%의 수분을 보유할 수 있었다. 반면 calcium carbonate, calcium oxide, fly ash등은 보수력이 낮은 펠렛 피복물질이었다. 펠렛 피복물질의 pH는 kaolin과 dialite에서 각각 6.8 및 7.4로 중성이었으나, limestone, calcium oxide, bentonite 등은 pH가 12.8, 13및 10으로 강알카리였다. 전기전도도는 강알카리인 limestone, calcium oxide에서 높았다. 이와 같이 높은 pH와 전기전도도를 보인 피복물질들은 당근종자의 펠렛에 적합하지 않았다. 펠렛 피복물질를 EDS로 분석한 결과, Talc는 주성분이 Si (71%)이었고, Mg도 29% 함유하였다. 반면 calcium carbonate의 주요성분은 Ca (66.6%)이었으며, 이외에 Si (22.9%)와 Mg (10.5%)를 함유하였다. 펠렛 형성정도는 kaoline, talc 및 talc + calcium carbonate 혼합재료에서 우수하였다. 펠렛종자의 경도는 bentonite로 펠렛된 종자에서 가장 높았다. 수분흡수 후 펠렛층의 분해형태는 talc, limestone, zeolite, 및 fly ash는 열개형이었고, 용해형은 calcium carbonate와 calcium oxide등이었다. 반면 bentonite와 vermiculite는 팽창형이었다. 수분흡수 후 펠렛층의 분해는 calcium carbonate 및 kaolin으로 펠렛된 종자에서 분해가 가장 빨랐다. 펠렛배율이 높아지면 발아속도$(T_{50})$는 지연되었다. 당근종자에서 적정 펠렛배율은 19배가 좋았다.

• 한국환경과학회지
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• 제16권6호
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• pp.745-750
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• 2007

Large scale of loess has been applied on the south - sea shore of the Korean peninsula to treat red tides, due to many fishery's devastation by red tides every year. However, coastal ecosystem is ruined by the huge amount of loess applied every year. Almost all creatures, living under water such as sea weeds, clams, and fishes, where loess was applied, are disappearing. In this paper, alternative methods of the loess application are investigated. The amount of loess could be reduced by the alternative methods, Especially, loess mixed with calcium oxide has excellent effects to reduce Cochlodinium polykrikoides numbers. It was found that when loess is used with calcium oxide(CaO), removal efficiency of red tides is highly increased. Moreover, the amount of loess could be reduced dramatically.