• Title/Summary/Keyword: Chemical stability

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Effect on Stability of Ginseng Saponins by Various Physical and Chemical Treatments (물리화학적 처리가 인삼 Saponin의 안정성에 미치는 영향)

  • 도재호;장진규
    • Journal of Ginseng Research
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    • v.10 no.2
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    • pp.193-199
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    • 1986
  • To investigate the stability of ginseng saponin, various physical and chemical treatments for red ginseng alcohol extract (70% ethyl alcohol) were carried out, and then the variations of ginseng saponin in extract were investigated by high performance liquid chromatography (HPLC) method. Irradiation of ${\gamma}$-ray, and ultraviolet ray, sonocatalysis by ultrasonicator, treatment of electronic range, catalytic ozonation did not or slightly affect degradation of ginseng saponins, but they were degraded by heat treatment.

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Antimicrobial and Other Properties of a New Stabilized Alkaline Glutaraldehyde Disinfectant/Sterilizer (병원에서 사용하는 수술도구 살균제, glutaraldehyde 용액의 살균 효과에 관하여)

  • 궁리환
    • YAKHAK HOEJI
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    • v.31 no.4
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    • pp.236-251
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    • 1987
  • The chemistry, antimicrobial properties, organic soil resistance, toxicity, corrosivity and chemical stability of stabilized alkaline 2%, glutaraldehyde solution(SGS) are discussed. SGS retains the maximum antimicrobial activity of alkaline glutaraldehyde solutions and the chemical stability here to fore observed only with acidic glutaraldehyde solutions. These improvements, along with the inherent resistance of glutaradehyde to neutralization by organic soil, allow SGS to be continuously used for 14 days in situations of high dilution, or 28 days in situations of low dilution.

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Reaction of Lithium 2-Pyridyloxyalkylcuprates Having Improved Thermal Stability with Acid Chlorides and $\alpha,\beta$-Unsaturated Ketones

  • Lee, Phil-Ho;Shim, Sang-Chul;Kim, Sung-Gak
    • Bulletin of the Korean Chemical Society
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    • v.7 no.6
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    • pp.425-428
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    • 1986
  • A new heterocuprate containing 2-pyridyloxy ligand, lithium 2-pyridyloxy-n-butylcuprate, has shown improved thermal stability and it reacts with acid chlorides to afford the corresponding ketones in high yields. Similarly, it can be effectively utilized in conjugate addition reactions of $\alpha,\beta$-unsaturated ketones. Of synthetic significance is that the complete utilization of n-butyl group in lithium 2-pyridyloxy-n-butylcuprate has been observed.

Phase Stability and Electronic Properties of $Bi_2BaLnCuO_{6+δ}$ Cuprates with Structure 2201 Type

  • V. E. Fedorov;N. G. Naumov;P. P. Samoilov;N. F. Zakharchuk;N. I. Matskevich;백우현
    • Bulletin of the Korean Chemical Society
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    • v.16 no.6
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    • pp.484-489
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    • 1995
  • The synthesis of new bismuth-barium containing members of layered cuprates with 2201 type structure was reported. By solution calorimetry the formation enthalpies for Bi2MLaCuO6.5 (M=Ba, Ba0.5Sr0.5, Sr) were obtained. Crucial influence of partial oxygen pressure and size of lanthanoid on stability of layered cuprates was shown. Electronic states of variable valence atoms were studied by voltammetry of solids.

The Molecular Mechanics Evaluation of the Stability of Bridgehead Olefins Containing Medium Rings

  • 김장섭
    • Bulletin of the Korean Chemical Society
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    • v.18 no.5
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    • pp.488-495
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    • 1997
  • The stability of bridgehead olefins containing 8 and 10 membered rings has been investigated by the MMX molecular mechanics calculation together with the GMMX conformational searching program. A number of 'hyperstable' bridgehead olefins, which have negative olefin strain values, have been found from the calculated values of strain energy and olefin strain for the series of in- and out-bicyclo[n.3.3]alk-1-ene and in- and out-bicyclo[n.4.4]alk-1-ene (n=1 to 8). For the bridgehead olefins with 'out' topology, hyperstable olefins were found in the systems having cyclononene or larger rings. For the bridgehead olefins with 'in' topology, hyperstable olefins were found in the systems having cyclodecene or larger rings.