• 동아시아식생활학회지
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• 제13권6호
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• pp.608-614
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• 2003

현미식초와 다슬기회분으로 제조한 액상의 초산칼슘(LCA)을 밀가루에 대하여 2, 4, 8% (v/w)되게 첨가한 빵(LCA-빵)의 품질특성을 조사하였다. 반죽의 pH는 대조구(5.38)보다 첨가구(5.39∼5.42)에서 높았으며 첨가량이 높을수록 높았다. LCA-빵의 굽기손실율은 10.11∼10.81%로 대조구의 10.73%와 뚜렷한 차이를 보이지 않았으며, loaf volume index는 대조구 7.12, 2% 첨가 7.18로 비슷하였으나 4% 및 8% LCA-빵은 각각 6.62 및 5.80으로 낮았다. 칼슘함량은 무첨가 빵에서 16mg/g, 2, 4 및 8% LCA-빵에서는 각각 30, 60, 120 mg/g이었다. LCA-빵의 경도, 점착성, 깨짐성은 대조구보다 높았으나 탄성과 응집성은 낮았다. LCA 첨가빵의 $L^{*}$ 값은 대조구보다 낮았으나 $a^{*}$ 값은 뚜렷한 차이가 없었고 $b^{*}$ 값은 높았다. 현미경 관찰결과 LCA의 첨가량이 증가할수록 기공이 불규칙적이며 전분입자가 불안정한 matrix를 형성하였다. 신맛과 쓴맛은 대조구와 유의적 차이는 없었다. 끈적한 정도는 대조구와 2∼4% LCA빵에서는 차이를 보이지 않았으나 8% LCA-빵에서는 높았다. 풍미와 종합적 기호도는 대조구와 2% LCA-빵은 비슷하였으나 4∼8% LCA-빵에서는 낮은 값을 보였다. 곰팡이 번식정도로 평가한 빵의 저장성은 2% LCA-빵에서는 뚜렷한 차이를 보이지 않았으나 4% LCA-빵은 2배, 8% LCA-빵은 3배로 연장되었다.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.404-416
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• 2020

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO₃) formation. Irregular vaterite-like CaCO₃ minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO₃ around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO₃^2- ions in the CaCO₃ were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.

• 전기화학회지
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• 제5권2호
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• pp.43-46
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• 2002

Commercial titanium rod was anodized in three types of electrolytes such as 0.06 mol/L $\beta-glycerophosphate+0.3mol/L$ calcium acetate, 0.06mol/L $\beta-glycerophosphate+0.3mol/L$ sodium acetate and 0.06 mol/L $\beta-glycerophosphate+5mol/L$ calcium phosphate. The titanium oxide layer $(TiO_2)$ was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron spectroscopy chemical analysis (ESCA). Numerous micropores were observed on the titanium oxide layer by SEM. The diameter of micropores increased with the increase of electrolytic voltage. The titanium oxide layer was composed of anatase structure. The phosphorous element was detected at 130 eV binding energy, but calcium was not found in the oxide layer because of lower contents. After anodizing the oxide layer was etched in the 30g/L NaOH solution at $80^{\circ}C$ for 1hr. The surroundings of micropores were much more smoothed and rounded than before alkaline etching.

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2002년도 제42회 종합학술대회 연제초록
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• pp.31-32
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• 2002

• Asian-Australasian Journal of Animal Sciences
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• 제26권1호
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• pp.134-142
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• 2013

The effect of modified atmosphere packaging (MAP; 30% $CO_2$+70% $N_2$ or 100% $N_2$) and an additive mixture (500 ppm rosemary extract, 3,000 ppm sodium acetate and 1,500 ppm calcium lactate) on the quality of pre-cooked hamburger patties during storage at $5^{\circ}C$ for 14 d was evaluated. The addition of the additive mixture reduced aerobic and anaerobic bacteria counts in both 30% $CO_2$-MAP (30% $CO_2$+70% $N_2$) and 100% $N_2$-MAP (p<0.05). The 30% $CO_2$-MAP was more effective to suppress the microbial growth than 100% $N_2$-MAP, moreover the 30% $CO_2$-MAP combined with additive mixture resulted in the lowest bacterial counts. The hamburger patties with additive mixture showed lower CIE $L^*$ and CIE $a^*$, and higher CIE $b^*$ than those with no additive mixture. The 30% $CO_2$-MAP tended to decrease the TBARS during storage regardless of the addition of additives. The use of 30% $CO_2$-MAP in combination with additives mixture was effective for maintaining the quality and extending the shelf-life of pre-cooked hamburger patties.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.23-23
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• 2018

In this study, new titanium alloys were prepared by adding elements such as tantalum (Ta), zirconium (Zr) and the like to complement the biological, chemical and mechanical properties of titanium alloys. The Ti-40Ta-xZr ternary alloy was formed on the basis of Ti-40Ta alloy with the contents of Zr in the contents of 0, 3, 7 and 15 wt. %. Plasma electrolytic oxidation (PEO), which combines high-voltage sparks and electrochemical oxidation, is a novel method to form ceramic coatings on light metals such as Ti and its alloys. These oxide film produced by the electrochemical surface treatment is a thick and uniform porous form. It is also composed of hydroxyapatite and calcium phosphate-based phases, so it has the characteristics of bone inorganic, non-toxic and very high bioactivity and biocompatibility. Ti-40Ta-xZr alloys were homogenized in an Ar atmosphere at $1050^{\circ}C$ for 1 hour and then quenched in ice water. The electrochemical oxide film was applied by using a power supply of 280 V for 3 minutes in 0.15 M calcium acetate monohydrate ($Ca(CH_3COO)_2{\cdot}H_2O$) and 0.02 M calcium glycerophosphate ($C_3H_7CaO_6P$) electrolyte. A small amount of 0.0075M zinc acetate and magnesium acetate were added to the electrolyte to enhance the bioactivity. The mechanical properties of the coated surface of Ti-40Ta-xZr alloys were evaluated by Vickers hardness, roughness test, and elastic modulus using nano-indentation, and the surface wettability was evaluated by measuring the contact angle of the coated surface. In addition, cell activation and differentiation were examined by cell culture of HEK 293 (Human embryonic kidney 293) cell proliferation. Surface properties of the alloys were analyzed by scanning electron microscopy(FE-SEM), EDS, and X-ray diffraction analysis (XRD).

• KSBB Journal
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• 제32권3호
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• pp.206-211
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• 2017

The physical method used to prevent a landslide has the risk of environmental pollution. Calcite forming bacteria (CFB) have been received increasing attention as a novel and environmental friendly strategy for the soil improvement. In this study, we selected 11 CFB strains with high calcite production. We also examined survivability and calcite productivity of the strains under various stress conditions to select strains with high resistance to various stresses. Two strains was selected by environment stress. Sphingobacterium sp. KJ-32 and Viridibacillus arenosi B-25 precipitate calcite more than other strains at pH 5 and $15^{\circ}C$ respectively. Bio-consolidated soil cakes were made using various calcium salts (calcium chloride, calcium acetate, calcium lactate, calcium gluconate) with mixed culture of 2 strains. Among them, the calcite made using calcium chloride was the largest. These observations demonstrate that this bio-consolidation technology has the potential for eco-friendly prevention of landslide and soil improvement.

• 한국축산식품학회지
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• 제30권4호
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• pp.685-694
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• 2010

The present study investigated the combined effects of modified atmosphere packaging (MAP) and organic acid salts on the quality and shelf-life of Hanwoo ground beef patties. The ground beef containing 500 ppm of ascorbic acid was prepared with air-packaging (Air-P), high oxygen-MAP (70% $O_2$+30% $CO_2$/OxyMAP), and nitrogen-MAP (100% $N_2$/NitroMAP), in combination with organic acid salts (1500 ppm of sodium acetate and 500 ppm of calcium lactate). The samples were stored for 11 d at $5^{\circ}C$. The pH value of ground beef patties decreased during storage in all the treatments. The ground beef patties with organic acid salts showed relatively higher level of pH during storage compared with non-added patties (p<0.05). Lipid oxidation was accelerated in OxyMAP while it was delayed in NitroMAP treated with organic acid salts. Nitro-MAP treated with organic acid salts was effective in stabilizing the color characteristics of lightness (CIE $L^*$) and redness (CIE $a^*$) during storage. Oxygen content in MAP was shown to be a more important factor affecting color stability and lipid oxidation of ground beef than organic acid salts. The aerobic and anaerobic bacterial counts were reduced both in OxyMAP and NitroMAP (p<0.05), and the lactic acid bacteria was inhibited by Oxy-MAP (p<0.05). Coliform bacteria decreased during storage as pH value was decreased in all treatments. According to the sensory evaluation, the ground beef patties in NitroMAP showed the best quality among all treatments during storage. Therefore, Hanwoo ground beef patties added with sodium acetate and calcium lactate and packed with NitroMAP showed better quality characteristics than other treatments. This packaging method is recommended and could be utilized for packaging hanwoo ground beef patties for improving quality and extending shelf-life.

• 한국식품위생안전성학회지
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• 제18권2호
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• pp.73-78
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• 2003

난각칼슘을 식초에 침지하여 제조한 양조칼슘, 현미칼슘과 난각칼슘분 및 침강성탄산칼슘을 흰쥐에 식이 후 칼슘의 혈청 중 보유량(흡수율)에 관하여 비교시험 결과는 다음과 같다. 1. 이온화율이 높은 양조칼슘(밀폐,통기)과 현미칼슘의 흡수는 경구투여 2시간 후에 최고치에 이른 것으로 나타났으며 이온화율이 낮은 난각칼슘분이나 침강성탄산칼슘은 이보다 늦은 5시간 후에 최고치에 이른 것으로 나타났다. 이는 이온화율이 높은 칼슘일 수록 흡수가 빠르게 진행되는 것으로 사료된다. 2. 흰쥐에 식이한 칼슘시료의 칼슘의 혈청 중 보유량은 현미칼슘＞양조칼슘(밀폐)>양조칼슘(통기)>침강성탄산칼슘>난각칼슘분 순으로 낮게 나타났다. 이는 이온화율의 순과 같았다. 3. 현미칼슘의 혈청중 칼슘농도가 난각칼슘분에 비하여 약 4배 높은 것으로 나타난 것으로 보아 칼슘의 혈청 중 보유량은 칼슘 섭취수준에 의한 영향보다 칼슘 이온화율과 밀접한 관련이 있는 것으로 사료된다. 4. 제조 조건에 따른 양조칼슘의 혈청 중 보유량은 밀폐조건이 통기조건에 비해 약 1.4배 높은 것으로 나타난 이유를 규명하기 위해서는 연구가 계속 진행되야 할 것으로 본다.

• 폴리머
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• 제38권2호
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• pp.225-231
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• 2014

고분자 결합제로 vinyl acetate(VA) 함량이 각각 30, 60%인 poly(ethylene-co-vinyl acetate)(EVA)를 사용하여 고농축 복합화약 시뮬란트의 유변학적 특성을 연구하였다. 충전제로는 탄산칼슘 및 research department explosive (RDX)와 물리적 특성이 유사한 Dechlorane을 사용하였다. 회분식 용융 혼련기를 사용하여 농축 현탁계를 혼련하였는데 최대 75 v%까지 충전이 가능하였다. 동적 기계적 물성 변화를 측정한 결과 Dechlorane이 탄산칼슘보다 결합제수지와 더 높은 상호작용을 보였다. 일정 전단속도 방식과 일정 전단응력 방식의 평판-평판 레오미터를 사용하여 현탁계의 미세구조의 변화가 유변물성에 미치는 영향을 조사하였고, Krieger-Dougherty 식을 사용하여 최대 충전 부피분율 및 고유점도를 구하였다. EVA31/Dechlorane 현탁계의 최대 충전 부피분율은 약 70 v%이고, 혼련시 전단응력이 약 2000 Pa 정도 부가되는 것이 적절함을 알 수 있었다.