• Journal of the Korea Concrete Institute
• /
• v.20 no.6
• /
• pp.713-719
• /
• 2008

Various types of coatings have been developed for use as reinforcement in concrete and to resist chloride environment. The most commonly used coatings are inhibited and sealed cement slurry coating, cement polymer compositing coating and epoxy coating. Cement slurry offers passive protection, epoxy coating offers barrier protection whereas polymer coating offers both passive protection and barrier protection. Moreover, damage during handling of the steel may result in disbondment of the epoxy coating, which would increase the risk of localized corrosion. In the present study, inhibiting technique was used to increase the calcium hydroxide content at the interface up to 20%. Calcium hydroxide provides a high buffering capacity that resists a local fall in pH and thus maintains the alkaline environment necessary to prevent chloride corrosion. This study examines the use of a calcium hydroxide coating on the steel surface to enhance the pH buffering capacity of steel-concrete interface. Finally, the chloride threshold level (CTL) of polymer inhibitive coating calcium hydroxide is evaluated.

• Food Science and Preservation
• /
• v.19 no.5
• /
• pp.727-734
• /
• 2012

For developing calcium supplement from the harmful marine organism starfish, the physiochemical property of the powdered starfish skeletal plate and the hydrolysis condition of the starfish digestive enzyme were studied. The optimal hydrolysis condition of the starfish digestive enzymes was at $55^{\circ}C$ for 12 h. The bulk densities of the powdered starfish skeletal plates of Asterias amurensis and Asterina pectinifera were $1.1{\pm}0.0$ and $1.2{\pm}0.0g/cm^3$, respectively. As for the median size, the values were 10.738 and $11.799{\mu}m$, respectively. According to the added concentration of sodium polyacrylate, the dispersibility rate of the powdered starfish skeletal plate was shown to be 6h at 0.0%, 3 days at 0.1%, 20 days at 0.2%, and until 30 days at 0.4%. The elementary composition of the powdered starfish skeletal plates from A. amurensis and A. pectinifera mainly consisted of calcium, and it formed 98.95 and 98.52% of the powdered starfish skeletal plates, respectively. The results of the X-ray diffraction (XRD) analysis showed that they were present in the form of $CaCO_3$. Based on these results, it is suggested that starfish skeletal plate can be utilized as a functional material for a calcium supplement.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1996.06b
• /
• pp.3-27
• /
• 1996

분체의 입자 배열이 불규칙한 경우뿐만 아니라 입자 크기가 극미세하여 X선회절분석이 불가능한 경우에도 비정질물질이라 한다. 수용액 속에서 이런 비정질 물질을 합성하기 위해서는 합성용액의 과포화도를 높여 계속 유지시킴에 따라 극미세 1차핵 생성의 지속적인 유도에 따른 입자 성장을 최대한 억제시켜야만 한다. 본 연구에서는 흡습제, 칼슘제 및 식품 첨가제 등으로 이용되는 비정질 탄산칼슘을 계에서 합성하고, 이때 생성된 비정질 상태의 겔을 수용액 환경을 변화시켜가면서 따라 결정화를 유도하고 탄산칼슘의 동질이상을 관찰하였다. CO2의 유속을 11/min, 교반속도를 600rpm으로 고정시키고, Ca(OH)2의 양을 10g에서 50g까지 변화시켜가면서 겔 상태의 비정질 탄산칼슘을 합성하였다. 이때 전기전도도는 CO2의 용해와 더불어 Ca(OH)2의 용해도가 증가함에 따라 변화하였으며, 반응종반부에는 겔화가 시작될 때까지 거의 일정하였다. 따라서, 이러한 사실들로부터 현탁액 내에서의 전기전도도의 변화는 Ca이온의 영향을 받는 것으로 사료된다. 비정질 탄산칼슘은 수용액에서 불안정하여 CO2 가스를 방출하면서 급격히 결정화되는데, 본 연구에서는 Ca(OH)2의 양을 20g으로 하여 위의 방법에 의해 얻어진 겔을 수용액의 종류와 농도 및 결정화 온도, 교반속도를 달리하면서 결정화시켰다. 교반속도를 100rpm으로 하여 물의 온도변화에 다라 결정화시킨 경우 전 온도범위에서 칼사이트상이었으며, 물의 온도가 5$^{\circ}C$일 경우에는 미세한 입자들이 응집된 형태였으나, 그 외의 온도변화조건에서는 모두 평균입경 0.4$\mu\textrm{m}$정도의 비교적 균일하 능면체 형태였다. 또한 교반속도를 500rpm으로 증가시켰을 경우에는 8$0^{\circ}C$에서 침상의 아라코나이트가 소량생성되었음을 SEM사진으로 관찰할 수 있었으며, 소량의 바테라이트도 혼재되어 결정화되었음을 XRD결과로 알 수 있었다. 교반속도를 100rpm으로 한 NH4Cl 0.5mol/l 수용액에서는 입자의 형태와 크기가 불규칙한 칼사이트로 결정화되었으며, MgCl2 0.05mol/l 수용액의 경우에는 순수한 H2O의 경우에서와는 달리 2$0^{\circ}C$에서는 모서리가 무딘 매우 균일한 크기의 칼사이트 입자가 관찰되었으며, 6$0^{\circ}C$부터는 아라고나이트가 생성됨을 관찰할 수 있었다. 따라서, 고온(8$0^{\circ}C$)의 농도 MgCl2 수용액(0.1, 0.2 mol/l)에서 교반속도를 높여(800rpm) 겔을 결정화시킨 결과 아라고나이트의 생성수율이 증가되는 것을 확인할 수 있었다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2008.04a
• /
• pp.138-140
• /
• 2008

현재 현수막의 코팅에서 기능을 부여하는 수요가 늘고 있다. 본 실험에서는 코팅제의 유기용제 사용으로 인한 환경오염 문제및 폐기물 처리비용 부담을 줄이기 위하여 수성코팅제를 개발하려한다. acryl binder, 탄산칼슘, silica, 유화제등을 혼합한 코팅제를 knife coating한 후 170$^{\circ}C$로 1분 30초간 열처리 하였다. 이때 acryl binder의 첨가비율은 35${\sim}$55%로 변화를 주었다. 처리한 폴리에스테르에 DTP printing을 한 후 CCM 측정, 내수성, 접착성을 알아본 결과 acryl binder의 첨가비율은 45%일때 가장 우수한 발색성 및 printing 특성을 나타내었다. 기존 수성코팅제에 대비 20${\sim}$30% 발색성이 개선되었다.

• Proceedings of the Korean Journal of Food and Nutrition Conference
• /
• 2000.12a
• /
• pp.54.2-54
• /
• 2000

일반식용의 참쑥과 강화지역 특산물인 강화약쑥의 첨가급식이 체성장 및 성분에 미치는 영향을 관찰하고자 89g 내외의 흰쥐(Sprague Dawley) 24두를 3개 동물군(대조군, 참쑥군 및 약쑥군)으로 나누어 4주간 해당 실험식이(대조식이, 5%참쑥식이 및 5%약쑥식이)로 급식하였다. 쑥의 일반영양 성분 함량은 참쑥 중 조단백질과 조회분은 약쑥보다 약 2%이상 높았으나 반대로 조지방은 약 2%낮았다. 또한 약쑥 중 칼슘은 참쑥보다 5.3배 높았으나 반대로 참쑥 중 망간, 아연, 철, 마그네슘은 2.8∼2.3배, 비타민A는 2.9배가 높았다. 체중 증가율과 식이효율은 참쑥군 과 약쑥군이 모두 대조군과 비슷하였다. 혈청 중 총단백질, albumin, 요소질소, creatinine, 뇨산, 총cholesterol, HDL-C, LDL-C, 당 함량과 amylase와 transaminase(GOT, GPT)의 활성이 참쑥군과 약쑥군 간에 유의성 있는 차이를 나타내지는 않았으나 LDH의 활성은 약쑥군이 대조군과 참쑥군에 비하여 감소(p<0.05)하였다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.4
• /
• pp.592-596
• /
• 2000

This study was carried out investigate the effect of sepiae as on the kimchi ferentation. Quality indices were pH, titratable acidity, reducing sugar content, microbial counts, and redness kimchi juice. Sepiae as retarded the decreasing rate of pH and the increasing rate of titratable acidity in kimchi during fermentation at 1$0^{\circ}C$, and the effect was more conspicouous at 1.5% than at 0.5%. Kimchi added with 1.5% sepiae as maintained a similar pH and titratable acidity after 5 days. Microbial counts of total and lactic bacteria were higher in sepiae os added kimchi than control control. Regardless of the of sepoae os, the redness of kimchi juice was gradually increased during storage.

• Resources Recycling
• /
• v.3 no.3
• /
• pp.27-31
• /
• 1994

We tested the limestone sludge produced in Pohang Iron & Steel Co., Ltd. as a filler powder for the effective use of portland cement. Hydration process was investigated by measuring the hydration rate, the amounts of non-evaporable water and compressive strength of cement-limestone sludge paste prepared by mixing limes-tone sludge with cement. The results obtained in this study can be summarized as follows: 1. There is no significant difference between the cases of adding up to 10% limestone sludge and those of unmixed cement system. However the reaction rate increases in the 5% limestone sludge system(due to the effects of fine). 2. The compressive strength increases proportionally with increasing the measured amount of non-evaporable water, Adding 5% limestone sludge also increases the strength a little higher, and the compressive strength and calcium silicate hydrates. In the case of the mixed limestone sludge, $2\theta$=$11.7^{\circ}$ peak appears in the samples of 28 days hydration. This peak indicted the presence of calcium carboaluminate hydrate. Although limestone sludge is generally regarded as a inert materials, some kinds of cement can produce a calcium carboaluminate by reacting with aluminate in cement pastes.

• Journal of Food Hygiene and Safety
• /
• v.27 no.4
• /
• pp.473-478
• /
• 2012

The nutritional properties of the Kochujang were investigated with Fermented Extract of Hizikia fusiforme. No big differences in proximate compositions(moisture, Crude protein, Crude fat, and Crude ash, Carbohyrate) were observed between Two kinds of kochujangs tested in this study, general kochujang purchased from a market(GK), kochujang added with Fermented Extract of Hizikia fusiforme(FGK). However, FGK showed higher level of Total free amino acid(15,929.5 ng/mg), amino nitrogen(1715.88 mg%) and mineral contens than GK. the analysis of volatile compounds using GC/MS revealde than the fermentation dramatically removed off-flavors such as Acetaldehyde, Silane rimethyl(2-methylphenyl)-, 1H-Indole 2-phenyl-1-(trimethylsilyl) in Fermented Extract of Hizikia fusiforme(FGK).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.5
• /
• pp.834-838
• /
• 2001

To investigate the effect of boiled-dried fusiforme for making kimchi, it was added as 0.1, 0.3 and 0.5% to brined Chinese cabbage by weight, respectively. Quality characteristics such as pH, titratable acidity, reducing sugar content, microbial loads were measured. Titratable acidity of 0.1% treatment showed a retarded increase compared to other samples, and maintained a higher reducing sugar content. Lactic acid bacteria numbers of boiled-dried fusiforme added kimchi were lower approximately by 2 log$_{10}$ CFU/mL after 10 day, which value was almost same as the control group. A 0.1% treatment of boiled-dried fusiforme showed no significant differences compared to the control in sensory evaluation.

• The Korean Journal of Pharmacology
• /
• v.30 no.1
• /
• pp.125-136
• /
• 1994

To characterize the SR Ca-release channel protein complex of crustacean, $^{45}Ca-release,\;[^3H]ryanodine$ binding, and immunoblot studies were carried out in the crayfish and/or lobster skeletal sarcoplasmic reticulum. Bmax and affinity of crayfish SR to ryanodine were lower than those of lobster SR. AMP (5mM) increased $[^3H]ryanodine$ binding significantly in both vesicles (P<0.05). $Mg^{2+}$(5mM) or tetracaine(1mM) inhibited $[^3H]ryanodine$ binding significantly in both vesicles (P<0.001), but ruthenium red $(10\;{\mu}M)$ inhibited it moderately. In SDS polyacrylamide gel electrophoretic analysis of crayfish SR vesicles, there was a high molecular weight band that showed similar mobility with Ca-release channel protein of lobster skeletal SR, but more rapid mobility (HMWBr) than that of rabbit skeletal SR (HMWBS). Immunoblot analysis showed that polyclonal Ab to lobster skeletal SR Ca-release channel protein was react with HMWBr of crayfish skeletal SR, but not with that of HMWBs of rabbit skeletal SR. ^{45}Ca-release from crayfish skeletal SR vesicles was increased by the increase of extravesicular calcium from $1{\mu}M$ to 1mM. This Ca-release phenomenon was similar, but more sensitive in the low concentration of $Ca^{2+}$, compared to that from lobster SR vesicles. AMP (5mM) or caffeine (10mM) did not affect to $^{45}Ca-release.\;^{45}Ca-release$ was inhibited slightly ($3{\sim}8%\;by\;Mg^{2+}$) (5mM) or tetracaine (1mM), and moderately (23%) by high concentration of ruthenium red $(300\;{\mu}M)$. From the above results, it is suggested that SR Ca-release channel protein of crustacean has different properties from that of the rabbit, and similar properties between crayfish and lobster in functional and immunological aspects, but Ca-release via crayfish channel may be more sensitive to calcium.