• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.131-136
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• 1999

In this study, novel activated silicate grout solution for injection grouting was prepared by the reaction of ordinary waterglass with alkaline earth metal salts mixture by means of the high-speed stirring method with strong shearing force, and its chemical and physical properties were investigated. The variation of its gelation time plotted with the amount of dilution water showed that this novel silicate had better gelation characteristics in comparison with ordinary waterglass. And some other engineering characteristics of this grout such as durability and mechanical properties were investigated experimentally. The whole experimental results established that this novel silicate grout was a good alternative with an existing ordinary waterglass grouting method.

• Journal of Welding and Joining
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• 제14권6호
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• pp.93-100
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• 1996

Effect of a flux composition on weld metal toughness in submerged arc welding with 60kgf/$\textrm{mm}^2$ grade C-Mo type wires was investigated and interpreted in terms of weld metal microstructure and hardenability. Flux workability was also studied by characterizing a weld bead profile. Compared to other weld metals, .weld metal used alumina basic flux with nickel showed lowest oxygen content, highest hardenability and the most acicular ferrite. The highest impact toughness of that weld metal, however, was attributed to the tough matrix due to the nickel rather than to the larger amount of acicular ferrite. Manganese silicate flux had better workability than alumina basic flux, showing broader welding conditions resulting in a depth-to-width ratio of 0.5. The composition of oxides in the weld metal was dependent on the flux composition, showing MnO-SiO$_2$-TiO in manganese silicate flux and MnO-SiO$_2$-Al$_2$O$_3$-TiO in alumina basic flux. MnO-SiO$_2$composition in both oxides was similar to a tephroite.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• 한국토양비료학회지
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• 제44권2호
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• pp.297-302
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• 2011

Acid drainage generated by pyrite oxidation has caused the acidification of soil and surface water, the heavy metal contamination and the corrosion of structures in abandoned mine and construction sites. The applicability of Na-acetate (Na-OAc) buffer and/or Na-silicate solution was tested for suppressing pyrite oxidation by reacting pyrite containing rock and treating solution and by analyzing solution chemistry after the reaction. A finely ground Mesozoic andesite containing 10.99% of pyrite and four types of reacting solutions were used in the applicability test: 1) $H_2O_2$, 2) $H_2O_2$ and Na-silicate, 3) $H_2O_2$ and 0.01M Na-OAc buffer at pH 6.0, and 4) $H_2O_2$, Na-silicate and 0.01M Na-OAc buffer at pH 6.0. The pH in the solution after the reaction with the andesite sample and the solutions was decreased with increasing the initial $H_2O_2$ concentration but the concentrations of Fe and $SO_4^{2-}$ were increased 10 - 20 times. However, the pH of the solution after the reaction increased and the concentrations of Fe and $SO_4^{2-}$ decreased in the presence of Na-acetate buffer and with increasing Na-silicate concentration at the same $H_2O_2$ concentration. The solution chemistry indicates that Na-OAc buffer and Na-silicate suppress the oxidation of pyrite due to the formation of Fe-hydroxide and Fe-silicate complex and their coating on the pyrite surface. The effect of Na-OAc buffer and Na-silicate on reduction of pyrite oxidation was also confirmed with the surface examination of pyrite using scanning electron microscopy (SEM). The result of this study implies that the treatment of pyrite containing material with the Na-OAc buffer and Na-silicate solution reduces the generation of acid drainage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.38-41
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• 2001

In this work, we have been studied the characteristics of each nitride film for the optimization of PMD(pre-metal dielectric) liner nitride process, which can applicable in the recent semiconductor manufacturing process. The deposition conditions of nitride film were splited by PO (protect overcoat) nitride, baseline, low hydrogen, high stress and low hydrogen, respectively. And also we tried to catch hold of correlation between BPSG(boro-phospho silicate glass) deposition and densification. Especially, we used FTIR area method for the analysis of density change of Si-H bonding and Si-NH-Si bonding, which decides the characteristics of nitride film. To judge whether the deposited films were safe or not, we investigated the crack generation of wafer edge after BPSG densification, and the changes of nitride film stress as a function of RF power variation.

• 한국세라믹학회지
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• 제43권2호
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• pp.136-141
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• 2006

The stabilizing behavior of heavy metals in the silicate glass containing Electric Arc Furnace dust (EAF dust) were studied by the Toxic Characterization Leaching Procedure (TCLP) test, and the change of crystalline phase and glass network structure were investigated as a function of EAF dust content added. The glass containing EAF dust of $30\;wt\%$ an oxygen/network former ratio(R) of $2\~3$ allowing a fairly stable network structure thus showed much lower heavy metal leaching concentration than that for containing EAF dust above $50\;wt\%$ at TCLP test. For the glass containing EAF dust $50\~60\;wt\%$, however, the R was over 3, which weakened the glass network structure and increased the heavy metals leachate. Adding the EAF dust to a glass decreased the degree of Si-O-Si symmetry and increased the number of non-bridging oxygen, which decreased the chemical durability of glasses. When the dust content in a glass was over $70\;wt\%$, the Zn and Fe ions reacted to form the spinel crystal rather than to bind to network structure of glass and leaching concentration of those ions from the specimen decreased, so the spinel phase could be attributed to lowering a heavy metal leaching.

• 공업화학
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• 제29권1호
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• pp.112-116
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• 2018

주조공정 중 주형제조 시 점결제로 사용되는 silicate계 바인더의 주요원료 중 하나인 물유리와 첨가제(Si, 알칼리 금속)의 혼합특성을 살펴보았다. 물유리와 첨가제 그리고 비율에 따라 제조된 혼합물은 FT-IR분석을 통해 분자결합구조를 살펴보았으며, 점도측정으로 분자구조와의 상관관계를 비교하였다. 물유리에 Si 소스의 제공은 물질 내 Si 망상결합을 촉진시켜 점도는 증가하였고, 알칼리 금속을 첨가하였을 경우에 물유리의 Si 망상결합을 억제하여 점도가 낮아졌다. 물유리와 리튬 실리케이트(lithium silicate, LS)의 혼합물의 점도는 LS의 함량이 20 wt% 이하에서는 LS의 함량이 증가할수록 증가하였지만, 20 wt%를 초과할 경우 점차 낮아졌다. 물유리에 KOH를 첨가함으로써 점도를 낮출 수 있었으며, 콜로이달 실리카(colloidal silica, CS) 또는 potassium methyl siliconate (PMS)와의 혼합을 효과적으로 이용하는 데 이용할 수 있다.

• Transactions on Electrical and Electronic Materials
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• 제15권2호
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• pp.87-90
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• 2014

The effects of electric field frequency on the ac electrical treeing phenomena in an epoxy/reactive diluent/layered silicate (1.5 wt%) were carried out, in needle-plate electrode arrangement. A layered silicate was exfoliated in an epoxy base resin, by using our ac electric field apparatus. To measure the treeing propagation rate, constant alternating current (AC) of 10 kV with three different electric field frequencies (60, 500 and 1,000 Hz) was applied to the specimen, in needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. As the electric field frequency increased, the treeing propagation rate increased. At 500 Hz, the treeing propagation rate of the epoxy/PG/nanosilicate system was $0.41{\times}10^{-3}$ mm/min, which was 3.4 times slower than that of the epoxy/PG system. The electrical treeing morphology was dense bush type at 60 Hz; however, as the frequency increased, the bush type was changed to branch type, having few branches, with very slow propagation rate.

• 한국세라믹학회지
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• 제13권4호
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• pp.15-19
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• 1976

Mutual interferences of alkali and alkali-earth metals in atomic absorption were examined. For determination of Na or K interfering elements increase the absorbancy, and for Ca or Mg decrease. Since influences of coexisting elements become nearly constant by addition of large amount of same coexisting element, could be use mixed standard solution for alkali or alkali-earth metal determination in the presence of other alkali and alkali-earth metals. The metals can be readily incorporated into scheme of rapid silicate analysis. Precision and accuracy are good.

• 한국안광학회지
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• 제1권1호
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• pp.1-14
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• 1996

Magic-Angle-Spinning NMR에 나타나는 $Li^+$ 이온의 운동과 관련된 알칼리 혼합 효과에 미치는 전이금속 산화물의 영향을 조사하기 위하여 불순물 $Fe_2O_3$를 0.1 mol% 첨가시킨 혼합 알칼리 Silicate 유리들을 제조하였고, 온도에 따라 $^7Li$ MAS-NMR 스펙트럼과 상온에서 $^7Li$ 스핀-살창 완화시간을 측정하였다. $Fe_2O_3$가 첨가되었을 때, 스펙트럼의 선폭이 조금 변화되었을 뿐이며 선 모양이 거의 변하지 않고 있다. 이 때문에, 스핀-스핀 완화 과정에서는 혼합 알칼리 효과가 충분히 나타나는 것으로 불수도 있지만 반드시 그렇지만은 않아 보인다. $Li^+$ 이온의 활성화 에너지가 혼합 알칼리 유리에서 오히려 감소하는 경향이 나타났다. 이것은 혼합 알칼리 효과가 아니다. 스핀-살창 완화시간, 완화 과정 분석을 통한 $Li^+$ 이온의 확산 환경, 그리고 핵 자가화 (nuclear magnetization) 등의 비교에 의하면, $^7Li$ 스핀-살창 완화 과정에서 알칼리 혼합 효과는 거의 나타나지 않는 것을 확인 할 수 있었다.