• 제목/요약/키워드: chromium trivalent

검색결과 71건 처리시간 0.192초

Growth of Phaseolus mungo under chromium stress - influence of chromate reducing bacteria

  • M. Rajkumar;Na, R.gendran;Lee, Kui-Jae;Lee, Wang-Hyu
    • 한국식물병리학회:학술대회논문집
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    • 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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    • pp.105.1-105
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    • 2003
  • The Plant growth Promoting rhizobacteria (PGPR), Pseudomonas sp. (A3) and Bacillus sp. (AT33) were isolated from the rhizosphere of Amaranthus blitum collected from soil contaminated with chromium. Both bacterial strains quantitatively reduced hexavalent chromium to trivalent chromium. Pseudomonas sp. broughter greater conversion of Cr6+ in the medium (100%) as compared to Bacillus sp.(62%). Phaseolus mungo seeds inoculated with Pseudomonas sp. or Bacillus sp. were grown under different concentration of chromium. The monitored parameters included elongation of shoot and root, fresh weight, dry weight and concentration of chromium in the shoot and root systems. As compared to non inoculated seedlings those inoculated with A3 and AT33 exhibited better growth.

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Growth of Phaseolus mungounder chromium stress - influence of chromate reducing bacteria

  • M. Rajkumar;Lee, Kui-Jae;Seo, Jae-Hwan;Lee, Wang-Hui
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2003년도 제10차 국제학술회의 및 추계정기 학술발표회
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    • pp.57-57
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    • 2003
  • The plant growth promoting rhizobacteria (PGPR), Pseudomonas sp. (A3) and Bacillus sp. (AT33) were isolated from the rhizosphere of Amaranthus blitum collected from soil contaminated with chromium. Bothbacterial strains quantitatively reduced hexavalent chromium to trivalent chromium. Pseudomonas sp. broughter greater conversion of Cr6+ in the medium (100%) as compared to Bacillus sp.(62%). Phaseolus mungo seeds inoculated with Pseudomonas sp. or Bacillus sp. were grown under different concentration of chromium. The monitoredparameters included elongation of shoot and root, fresh weight, dry weight and concentration of chromium in the shoot and root systems. As compared to non inoculated seedlings those inoculated with A3 and AT33 exhibited better growth.

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경질크롬도금 대체용 Ni계 합금도금 기술 (Ni-BASE ALLOY SYSTEMS AS ALTERNATIVE TO HEXAVALENT CHROMIUM)

  • Chang, Do-Yon;Lee, Kyu-Hwan;Kwon, Sik-Chol
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2003년도 추계학술발표회초록집
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    • pp.11-11
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    • 2003
  • Electroplated hexavalent chromium coatings have been used in many technical applications since it was invented by G.J. Sargent in 1920. Because of the environmental problems and health risks associated with the use of hexavalent chromium, there has been an extensive search for alternative coatings with properties such as corrosion resistance and wear resistance, at a reasonable cost. However there is no single substitute that meets all the desirable performance characteristics of chromium. Advanced techniques, such as alloy plating, electroless plating, trivalent chromium plating, plasma and thermal spray coating, PVD and ion implantation, have been applied for replacing hexavalent chromium plating.

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Plasma Aided Process As Alternative to Hard Chromium Electroplating

  • Kwon, Sik-Chol;Lee, K.H.;Kim, J.K.;Kim, M.;Lee, G.H.;Nam, K.S.;Kim, D.;Chang, D.Y.
    • 한국표면공학회지
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    • 제36권1호
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    • pp.48-58
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    • 2003
  • This paper will present an overview of toxicity of hexavalent chromium as well as effort for its replacement by a wide spectrum of alternative materials and technologies. Cr-based materials such as trivalent electrodeposit will be one of strong candidates for hard chromium by surface modification of its surface hardness. Ni-base alloy deposits has proved its application in specific mold for glass. HVOF has been studied in aircraft and military sector. There are still under way of development for commercially available alternatives. To date, no single coating has been identified as universal process as comparable to conventional hard chromium electroplating.

Characterization of Cr-P-C/MoS2 composite plating electro-deposited from trivalent chromium

  • Park, Jong-Kyu;Seo, Sun-Kyo;Byoun, Young-Min;Lee, Chi-Hwan
    • Journal of Ceramic Processing Research
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    • 제19권6호
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    • pp.445-449
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    • 2018
  • Chromium plating is a common surface treatment technique extensively applied in industry due its excellent properties which include substantial hardness, abrasion resistance, corrosion resistance, surface color, and luster. In this study, the effect of $MoS_2$ particles of the composite coating was investigated. To improve the lubrication of mold, $Cr-P-C/MoS_2$ composite plating was studied by varying the $MoS_2$ content. The current efficiency of the composite plating incorporated $MoS_2$ particles was increased at $MoS_2$ contents of 0.5 and 1.0 g/l due to the incorporation of fine particles. On the other hand, when the content of $MoS_2$ is 1.0 g/l or more, the current efficiency is lowered due to an increase in impact on the cathode surface. In order to evaluate the mechanical properties of Scratch test were conducted. Scratch test confirmed the lubricity and abrasion resistance characteristics revealed that the composite plating with added $MoS_2$ had relatively low surface roughness and uniform surface modification to improve its properties.

A Study of the Potential Interference of ArC+ on the Direct Determination of Trivalent Chromium and Hexavalent Chromium Using Ion Chromatography Coupled with ICP-MS

  • Nam, Sang-Ho;Park, Young-Il;Kim, Jae-Jin;Han, Sun-Ho;Kim, Won-Ho
    • Bulletin of the Korean Chemical Society
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    • 제25권4호
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    • pp.447-451
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    • 2004
  • Low and high resolution inductively coupled plasma mass spectrometry (ICP-MS) coupled with ion chromatography (IC) has been investigated for speciation of Cr(III) and Cr(VI). In particular, the interference of ArC^+formed by the carbon in a sample on the simultaneous determination of Cr(III) and Cr(VI) has been studied. In chemical speciation, this study shows that quadrupole type ICP-MS with low resolution has a limitation of simultaneous determination fo chromium species if the sample contains the carbon elements. The interference problems can be solved by high resolution ICP-MS.