• Asian-Australasian Journal of Animal Sciences
• /
• 제2권4호
• /
• pp.579-582
• /
• 1989

Previous experiments have shown that aqueous sodium silicate ingested in drinking water may modify the gastrointestinal uptake and(or) tissue retention of certain trace elements, including heavy metals. The present experiment tested, with a mineral balance trial using sheep, the hypothesis that dietary silicic acid could modify uptake, retention and(or) biological effects of dietary Cd. Twenty-four wethers were fed a fibrous diet of ground alfalfa hay and cottonseed hulls to which either 0 or 150 ppm Cd was added as $CdCl_2$ and 0, .5 or 1% silicic acid (as dry matter of the diet). Body weight, feed intake, excretion of urine (volume) and feces (weight), digestibility of dry and organic matter, retention of nitrogen, and packed cell volumes of blood were not affected by either Cd or silicic acid (P<.10). Cadmium decreased (P<.05) Ca retention and increased (P<.01) Mg retention. Silicic acid decreased (P<.05) K retention. Silicic acid failed (P<.01) to modify the retention of added dietary Cd. Body retention of K, Mn and Ni in response to silicic acid varied with Cd levels. If Cd is interfering with mineral retention, silicic acid may be effective in preventing this interference.

• Asian-Australasian Journal of Animal Sciences
• /
• 제5권2호
• /
• pp.279-283
• /
• 1992

Eighteen wether lambs averaging 32 kg were used to determine the effects of dietary silica, added as silicic acid, on mineral metabolism. Lambs were fed 1200 g daily of a coastal Bermuda grass based diet supplemented with either 0, .5 or 1.5% silicic acid. A 7-d total collection of urine and feces was conducted after lambs had adjusted to the dietary treatments for 19 days. Urinary excretion of silica was higher (p<.01) in lambs fed added silicic acid. Ruminal soluble concentrations of manganese tended to be lower (p<.10) and apparent absorption and retention of manganese were lower (p<.05) in lambs supplemented with silicic acid compared to control lambs. Apparent absorption and retention of calcium were slightly lower (p<.10) in silicic acid fed lambs. No differences in urinary between lambs fed .5 and those given 1.5% silicic acid. Phosphorus, magnesium, iron, zinc and copper absorption and retention were not affected by treatment.

• 한국식품영양과학회지
• /
• 제26권6호
• /
• pp.1028-1032
• /
• 1997

Low-temperature crystallization method silver nitrate-impregnated silicic acid column chromatography were applied for the isolation of pure $\alpha$-linolenic acid(ALA) from perilla seed oil. ALA or 78% in purity(HALA; yield, 83%) was obtained from the fatty acid mixture(ALA, 65.7%) derived from perilla oil by the low-temperature crystallization method, when the mixture was frozen at -8$0^{\circ}C$ for 210min. ALA over 90% in purity(yield, 71%) was also obtained from HALA ethyl esters(ALA, 78%) by the silver nitrate-impregnated silicic acid column(100cm$\times$10cm, i.d.) chromatography. In addition, the silver nitrate-impregnated silicic acid could be semipermanently used for isolation of ALA, because $Ag^{+}$ ion was not dissociated from the stationary phase.

• 한국세라믹학회지
• /
• 제33권8호
• /
• pp.915-920
• /
• 1996

콜로이드 졸-겔법에 의해 초미립자 mullite 분말을 제조하였다. Al2O3의 출발 물질로 aluminum isopropoxide $[Al(i-OC_3H_7)_3]$을, $SiO_2$ 출발 물질로 규산 나트륨으로부터 tetrahydrofuran(이후 THF로 약기함)으로 추출한 규산을 사용하였다. 규산 나트륨은 규산을 생성시키기 위하여 묽은 황산으로 산성화시킨 다음 THF로 추출하였다. Mullite 분말은 졸-겔법에 의해서 Si 추출율와 Na 제거율을 조사한 규산과 aluminum isopropoxide로 부터 합성되었다. THF로 추출한 규산의 불순물 함량은 0.04% 이하이었다. 합성된 mullite 분말은 $3Al_2O_3{\cdot}2SiO_2$ 조성을 갖고 불순물의 함량은 0.0462% 이하의 직경 $0.05{\mu}m$ 정도의 결정상이었다. EDS, XRD, TG/DSC, SEM, FT-IR, ICP, TEM등으로 mullite 분말의 특성을 조사하였다.

• 한국입자에어로졸학회지
• /
• 제12권3호
• /
• pp.65-72
• /
• 2016

Nanoporous $SiO_2$ particles containing different pore volume and size were prepared from silicic acid by a spray pyrolysis. The pore size, pore volume and particle size could be controlled with varying the precursor concentration, reaction temperature, and amount of organic templates such as Urea and poly ethylene glycol (PEG). The pore size distribution, pore volume and specific surface area of as-prepared particles were analyzed by BET and BJH methods, and the average particle sizes were measured by a laser diffraction method. The nanoporous $SiO_2$ particles ranged $0.6-0.9{\mu}m$ in diameter were successfully synthesized and the average particle size increased as the silicic acid concentration increased. The morphology of nanoporous $SiO_2$ particles was spherical and pores ranged 1 - 40 nm in diameter were measured in the particles. In case of Urea added into silicic acid, it showed no much difference in the morphology, pore size and pore volume at different Urea concentration. On the other hand, when PEG was added, it was clearly observed that pore diameter and pore volume of the particles surface increased with respect to PEG concentration.

• 한국작물학회지
• /
• 제51권6호
• /
• pp.513-518
• /
• 2006

This study was conducted to investigate the relations between brown planthopper (BPH, Nilapavata lugens) resistance and specific organic acids (oxalic acid, silicic acid, and trans-aconitic acid) known as BPH sucking inhibitors on different rice varieties and/or lines. There were no specific relations between BPH resistance and the contents of oxalic and silicic acids in the rice plant tissues. However, the stronger the BPH resistance was occurred, the higher the content of trans-aconitic acid was contained in the rice plants. The relations between the injury rate of rice plant by BPH and the content of trans-aconitic acid in the rice plants were negatively correlated, which were -0.84 and -0.82 at 30 and 60 days after seeding, respectively. Therefore, the content of trans-aconitic acid in rice plant tissues might be utilized as an index for improving BPH resistance of rice varieties.

• 한국식품과학회지
• /
• 제19권5호
• /
• pp.392-396
• /
• 1987

한국백삼의 유리페놀성 분획(free phenolic acid fr.)에서 phenolic acid의 분리 정제방법을 검토하였다. 먼저 silicic acid column에 의해 소분획으로 나누고 prep TLC 및 HPLC하여 정색반응 및 Pf차에 의해 phenolic acid로 추정되는 두 개의 화합물을 순수 분리하고, 결정을 얻어 UV, IR, MS, NMR로 그 구조를 밝힌 결과 ferulic acid와 vanillic acid로 확인되었다.

• 한국광물학회지
• /
• 제20권4호
• /
• pp.247-253
• /
• 2007

규질이암의 열처리 및 산 침출이 소듐 실리케이트나 규산 수용액과 같은 실리카 전구물질 순도에 미치는 영향을 연구하였다. 규질이암의 열처리 온도, 산 침출시 염산 농도 및 황산 농도를 변화시키며 전구물질 내에 실리콘 함량을 최대한 높이면서 에너지 및 화학약품의 소모는 최소화하는 조건을 구하였다. 열처리는 $600^{\circ}C$, 산 침출은 1.56 M의 염산만 사용하였을 경우 최적이었다. 소듐 실리케이트와 규산 수용액의 실리콘 순도는 각각 최대 99.2%와 99.5%였다.

• 한국세라믹학회지
• /
• 제37권6호
• /
• pp.517-523
• /
• 2000

Effect of catalysts, which was catalyzed by acid(HCl and HNO3) and base(NH4OH), on characteristics of the mullite powders prepared by sol-gel methdo wa sinvestigated by XRD, TGA, SEm AND BET. As a result, weight loss as a function of catalysts was in order of HCl=32.6%>HNO3=25.44%>Non=24.0%>NH4OH=22.5%. The mullite powder dried at 100$^{\circ}C$ appeared spherical shape in acid catalyst and different shape in base catalyst, but sintering powder at 1400$^{\circ}C$ appeared very fine particle of 0.05∼0.1$\mu\textrm{m}$ regardless of catalysts. In all cae, the pore quantity, which was capable to adsoprtion, was decreased with increasing temperature. In base catalyst, no change of special surface area in mullite appeared.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2022년도 추계학술대회
• /
• pp.121-121
• /
• 2022

When 7 kg·10a^-1, which is less than the nitrogen standard application amount of 9 kg·10a^-1, is applied, the protein content is lowered and the palatibility is improved. In order to examine the applicability of nitrogen fertilization of 7 kg·10a^-1 nationwide, soil samples were collected from 240 paddy fields in 8 provinces in 2021, and the organic matter content, effective phosphoric acid, and effective silicic acid were analyzed for each sample. As a result of one-way ANOVA analysis between samples collected for each province, there was no significant difference in the content of organic matter, effective phosphoric acid, and effective silicic acid except for some provinces. The contents of organic matter was higher than the appropriate level(25 ~ 30 g·kg^-1) except for Gyeongsangbuk-do, the effective phosphoric acid was higher than the appropriate level(80~120 mg·kg^-1) in all provinces, and the effective silicic acid was lower than the appropriate level(157 ~ 180 mg·kg^-1) except for Gyeonggi-do, Jeollanam-do and Gyeongsangnam-do. As a result of analyzing the recommended fertilization amount based on the nitrogen application amount of 7 kg·10a^-1, 68.3% ofthe 240 samples were able to give nitrogen fertilizer less than 7.5 kg·10a^-1, and the rest had to be given more than that to satisfy the standard fertilization amount. As a result of this study, 68.3% of rice paddies nationwide can be cultivated with a standard fertilization amount of 7 kg·10a^-1, however it was thought that continuous nutrient management would be required for other paddies.