• Journal of Korea Foundry Society
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• v.28 no.6
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• pp.243-251
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• 2008

자동차 및 항공기 부품용 고온 다이캐스팅 마그네슘 합금에 대한 연구가 활발히 진행되고 있다. 알루미늄을 주된 합금원소로 하여 희토류원소나 알칼리토금속 등을 첨가하는 3원계 합금 및 각 원소들을 조합하는 4원계 합금이 개발되었다. 이들 합금의 크립 저항성은 금속간 상에 의한 결정 입계 강화에 기인한다. 그 동안의 합금조성 개발의 핵심은 결정 입계의 이동을 유발하여 고온 변형을 유발하는 고온 불안정 석출상의 생성을 억제하는 것이었다. Mg-Al계 합금에 희토류원소를 첨가하면 고온 안정상의 생성으로 고온 특성이 향상되지만 희토류원소의 경제성이 단점이다. 고비용의 희토류원소를 대신하기 위해 알칼리토금속을 첨가하는 합금 및 이들 원소를 조합하는 합금이 개발되었다. 본고에서는 알칼리토금속을 첨가할 경우에 발생하는 생산성의 저하 등의 단점을 보완하는 알칼리토금속산화물이 첨가된 합금을 소개하였는데 이는 1) 비고용성 2) 융점유지 3) 주조성유지 4) 재활용성 5) 경제성 등의 특징이 있다.

• Journal of the Korean Chemical Society
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• v.37 no.9
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• pp.820-825
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• 1993

The ion exchange capacity of HDBPDA ion exchanger, {(4,5) : (13,14)-dibenzo-6,9,12-trioxa-3,15,21-triazabicyclo[15.3.l]heneicosa-(1,17,19)(18,20,21) triene ion exchanger: HDBPDA ion exchanger} was 3.8 meq/g. The distribution coefficients of alkali and alkaline earth metal ions in water and the various concentration of hydrochloric acid were determined. Concentration of hydrochloric acid have almost not influenced on the distribution coefficients of alkali and alkaline earth metal ions, but generally, the distribution coefficient was slightly increased with decrease of concentration of hydrochloric acid. The distribution coefficients of metal ions in water are larger than those of various hydrochloric acid concentrations. Also, alkali and alkaline earth metal ions are separated by column ion exchange chromatography using HDBPDA ion exchange with water as eluent. The distribution coefficents of alkali and alkaline earth metal ions were increased with increase of ionic radii of metal ions.

• Analytical Science and Technology
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• v.10 no.1
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• pp.60-65
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• 1997

Solvent extraction of alkali metal and alkaline earth metal cations by mono-crown ether(benzo-15-crown-5) and bis-(crown ether)s(ethylenediamine bis(4'-formyl benzo-15-crown-5)) containing benzo-15-crown-5 moieties were investigated with water-chloroform system at $25^{\circ}C$. The order of the extraction equilibrium constants($K_e$) and the complexation constants($K_c$) for the alkali metal and alkaline earth metal cations with mono-crown ether and bis-(crown ether)s were Ca(II)>Na(I)>Sr(II)>K(I)>Mg(II)>Rb(I) and Sr(II)>Ca(II)>K(I)>Rb(I)>Mg(II)>Na(I) respectively. These results were explained in terms of the size effect of metal cation and electron density effect. Also, the bis-(crown ether)s was found to extract metal cations more effectively than the corresponding mono-crown ether.

• Analytical Science and Technology
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• v.6 no.5
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• pp.471-477
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• 1993

The novel macrocylic ligand {(4, 5):(13, 14)-dibenzo-6, 9, 12-trioxa-3, 15, 21, -triazabicyclo [15. 3. 1]heneicosa-(1, 17, 19)(18, 20, 21) triene: HDBPDA} was synthesized, and protonable constants of the ligand and the complex stability constants with alkali metals alkaline earth metals were determined. We evaluated the resolution factor(${\Delta}$) from equation that inducing from stability constants(pK). Also, this ligand was grafted on chloromethylated styrene-divinyl benzene(Merrifield resin) for HDBPDA, ion exchanger. Alkali and alkaline earth metal ions were separated using water by the column chromatography with this ion exchanger. Selectivity(${\alpha}$) and resolution(Rs) of alkali and alkaline earth metal ions were measured from the elution curves chromatogram. The selectivity and resolution values of the various ions calculated from the elution curves were compared with those abtained from pK values. The results were in a good agreement between tow methods. Ion exchange capacity of the resin were determined using the alkali and alkaline earth metal ions and pH dependence of capacity was also discussed.

• Analytical Science and Technology
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• v.6 no.3
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• pp.261-265
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• 1993

The ion exchange capacity of DBPDA ion exchanger, {(4,5):(13,14)-dibenzo-6, 9, 12-trioxa-3, 15, 21-triazabicyclo [15.3.1] heneicosa-1(21), 17, 19-triene-2, 16-dione : DBPDA ion exchanger} was 4.2meq/g. The distribution coefficients of alkali and alkaline earth metal ions in the various concentrations of hydrochloric acid were determined using DBPDA ion exchanger. Also alkali and alkaline earth metal ions were separated using DBPDA ion exchanger. From these results the effect of pH of solution and ionic radii of the metal ions on the distribution coefficients of alkali and alkaline earth metal ions were discussed.

• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.109-112
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• 1970

액체구조의 천이상태 이론을 알칼리토금속 염화물에 적용시켜서 상태합을 유도하였다. 이 상태합으로부터 $SrCl_2$와 $BaCl_2$의 증기압, 몰부피, 엔트로피등의 열역학적 성질을 계산하여 실험치와 비교하였으며, 천이상태 이론이 용융염에도 잘 적용된다는 결론을 얻었다.

• The Journal of the Acoustical Society of Korea
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• v.29 no.2
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• pp.111-117
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• 2010

Sonoluminescence (SL) is the light emitting phenomenon accompanied with ultrasonic cavitation in liquid. It attracts many interests because physics behind it remains uncertain and few applications have appeared. It has been known that the color of SL changes in solutions which include metallic ions. In the present work, colors of SL in alkali metallic and alkaline earth metallic ions were considered. RGB component was used to analyze the color of SL. By using RGB component, it was found that color of SL in metallic solution can be resolved into color of SL in pure water and flame color of metal which is different from high intensity color of line spectrum of alkaline earth metal. From this result, influence of metallic ion on SL and the temperature on violent collapsing of cavitation bubble was discussed.

• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.351-359
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• 1992

Interaction of xenon with alkaline-earth cations in Y zeolite supercage was studied by xenon adsorption and $^{129}Xe$ NMR experiments. The CaY and the BaY samples were prepared by exchanging $Ca^{2+}$ and $Ba^{2+}$ into a high-purity NaY zeolite. Xenon adsorption isotherms of these samples were obtained by using a conventional volummetric gas adsorption apparatus in the range of 260 to 320 K and the chemical shift in the $^{129}Xe$ NMR spectrum of the adsorbed xenon was measured at 296 K. The chemical shift against pressure was quantitatively explained assuming that the xenon gas exchanged very rapidly between various adsorption sites consisting of zeolite-framework surface and alkaline-earth ion. From this analysis, it was found that the alkaline-earth ion adsorbed xenon more strongly than $Na^+$ ion and zeolite-framework surface. Baring on the difference of the adsorption strength, the number of the alkaline-earth cations present in the zeolite supercage could be estimated by analyzing the adsorption isotherm.

• Analytical Science and Technology
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• v.8 no.2
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• pp.187-193
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• 1995

A PVC membrane ion-selective electrodes based on N,N,N,N-tetrabenzylethylenediamine as neutral carrier has been prepared by addition of plasticizers such as phthalates and sebacate and liphophillic additives such as NaTPB. The membrane electrodes were investigated to the electric resistance, response range to hydrogen ion and the interfering effect of alkali and alkline earth metals. A electric resistance hardly had on effect of plasticizers. In case of 0.7% NaTPB added to membrane, response of the electrodes were shown the values near to theoretical Nernstian slope and interferences by alkali and alkaline earth metal were few influenced. The performances of pH-selective electrodes were shown linerality to hydrogen ion between pH 2 and 10 in the presense of alkali and alkaline earth ions. Reproducibility and stability tests were shown good results in the same pH range.

• Analytical Science and Technology
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• v.11 no.4
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• pp.248-253
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• 1998

The adsorption and separation behaviors of alkali, alkaline earth and transition metal ions using a poly-dibenzo-18-crown-6 were investigated in aqueous solution. The adsorption degree(E) and distribution ratio(D) of alkali, alkaline earth metal ions were Li(I)$t_R$) of metal ions were affected by the adsorption degree(E) and distribution ratio(D). This results showed good separation efficiency of K(I), Sr(II), Ag(I) and Pb(II) from the mixed metal solution.