• 한국식품조리과학회지
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• 제13권4호
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• pp.478-483
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• 1997

수확 시기가 다른 오대벼와 만금벼 쌀가루를 에테르와 85% methanol로 탈지하여 탈지된 지방질의 차이가 멥쌀가루의 성질에 미치는 영향을 조사하였다. 쌀가루 시료중 전분 입자의 형태는 다각형이었고, X-선 회절도에 의한 결정형은 A형으로 탈지에 의한 변화는 없었다. 아밀로오스 함량은 에테르로 추출한 조지방질 탈지 쌀가루의 경우 무처리 시료와 비슷하였으나 메탄올로 추출한 총지방질 탈지 쌀가루는 증가하였고, 물결합 능력은 탈지에 의해 모두 감소하였다. 온도 증가에 따른 팽윤력은 오대벼 쌀가루가 만금벼 쌀가루보다 높았으며, 품종에 관계없이 조지방질 탈지 쌀가루는 무처리 시료와 비슷한 경향을 보였다. 총지방질을 탈지하면 85$^{\circ}C$까지는 높은 팽윤력을 보였으나 95$^{\circ}C$ 이상에서는 조지방 탈지 > 무처리 > 총지방 탈지 쌀가루 순으로 감소하였다. 모든 시료에서 가용성 물질의 용출 양상은 팽윤력과 같은 경향을 보였으며 용출된 가용성 물질의 겉보기 아밀로오스 함량은 총지방질 탈지 쌀가루를 85$^{\circ}C$ 이상 가열했을 때 급격한 증가를 보였다.

• 농업과학연구
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• 제43권4호
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• pp.522-536
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• 2016

Fluorine is unique chemical element which occurs naturally, but is not an essential nutrient for plants. Fluoride toxicity can arise due to excessive fluoride intake from a variety of natural or manmade sources. Fluoride is phytotoxic to most plants. Plants which are sensitive for fluorine exposure even low concentrations of fluorine can cause leave damage and a decline in growth. All vegetation contains some fluoride absorbed from soil and water. The highest levels of F in field-grown vegetables are found up to $40mg\;kg^{-1}$ fresh weight although fluoride is relatively immobile and is not easily leached in soil because most of the fluoride was not readily soluble or exchangeable. Also, high concentrations of fluoride primarily associated with the soil colloid or clay fraction can increase fluoride levels in soil solution, increasing uptake via the plant root. In soils more than 90 percent of the natural fluoride ranging from 20 to $1,000{\mu}g\;g^{-1}$ is insoluble, or tightly bound to soil particles. The excess accumulation of fluorides in vegetation leads to visible leaf injury, damage to fruits, changes in the yield. The amount of fluoride taken up by plants depending on the type of plant, the nature of the soil, and the amount and form of fluoride in the soil should be controlled. Conclusively, fluoride is possible and long-term pollution effects on plant growth through accumulation of the fluoride retained in the soil.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.586-591
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• 2001

This research investigated the feasibility of the accelerated carbonation of cement waste forms with carbon dioxide in a supercritical state. Hydraulic cement has been used as a main solidification matrix for the immobilization of radioactive and/or hazardous wastes. As a result of the hydration reaction for major compounds of portland cement, portlandite (Ca(OH)$_2$) is present in the hydrated cement waste form. The chemical durability of a cement form is expected to increase by converting portlandite to the less soluble calcite (CaCO$_3$). For a faster reaction of portlandite with carbon dioxide, SCCD (supercritical carbon dioxide) rather than gaseous $CO_2$, in ambient pressure is used. The cement forms fabricated with an addition of slated lime or Na-bentonite were cured under ambient conditions for 28days and then treated with SCCD in an autoclave maintained at 34$^{\circ}C$ and 80atm. After SCCD treatment, the physicochemical properties of cement matrices were analyzed to evaluate the effectiveness of accelerated carbonation reaction. Conversion of parts of portlandite to calcite by the carbonation reaction with SCCD was verified by XRD (X-ray diffraction) analysis and the composition of portlandite and calcite was estimated using thermogravimetric (TG) data. After SCCD treatment, tile cement density slightly increased by about 1.5% regardless of the SCCD treatment time. The leaching behavior of cement, tested in accordance with an ISO leach test method at 7$0^{\circ}C$ for over 300 days, showed a proportional relationship to the square root of the leaching time, so the major leaching mechanism of cement matrix was diffusion controlled. The cumulative fraction leached (CFL) of calcium decreased by more than 50% after SCCD treatment. It might be concluded that the enhancement of the characteristics of a cement matrix by an accelerated carbonation reaction with SCCD is possible to some extent.