• Title/Summary/Keyword: Metal

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Molecular Wire World Having Metal Complexes

  • Choi, Chang-Shik
    • Rapid Communication in Photoscience
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    • v.3 no.3
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    • pp.42-47
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    • 2014
  • Development of molecular and supramolecular systems showing efficient photoinduced energy or electron transfer are of current research interest due to their applications in various chemical and biological processes. Various polypyridine metal complexes including Ru(II), Ru(III), Os(II), Pt(II), Fe(II), Re(I), Ir(III) and so on as a metal center introduce for expanding some more understanding of molecular-scale photoelectronics. Their complexes are concisely classified by the types of relay ligands as follows; (a) metal-direct ligand-metal system; dinuclear or trinuclear systems, (b) metal-nonconjugated ligand-metal system and metal-nonconjugated ligand system having flexible/rigid ligand, (c) metal-conjugated ligand-metal system, and (d) conjugated ligand-metal-conjugated ligand system and metal-self assembly ligand-metal system. It is pointed out that the role played by the relay ligands is important in constructing the metal complexes.

A study on the removal of mixed heavy metal ions using crab shell (게 껍질을 이용한 수중의 복합 중금속 제거에 관한 연구)

  • Kim, Dong-Seog
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.729-735
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    • 2002
  • In order to examine the inhibition effect of other heavy metal ions on the removal of heavy metal ions by crab shell in aqueous solution, 10 heavy metal ions $(Cr^{3+},\;Cd^{2+},\;Ni^{2+},\;Zn^{2+},\;Hg^{2+},\;Cu^{2+},\;Mn^{2+],\;Fe^{2+},\;Fe^{3+},\;Pb^{2+})$ were used as single heavy metal ions and mixed heavy metal ions, respectively. In single heavy metal ions, $Pb^{2+},\;Cr^{3+},\;Cu^{2+}$ were well removed by crab shell, however, $Cd^{2+},\;Ni^{2+},\;Zn^{2+},\;Mn^{2+}$ were not. The heavy metal removal increased as the increase of covalent index (Xm$^2$r), and the relationship classified heavy metal ions as 2 heavy metal groups $(Fe^{3+},\;Fe^{2+},\;Cu^{2+},\; Cr^{3+},\;Mn^{2+},\;Ni^{2+},\;Zn^{2+}\;group\;and\;Pb^{2+},\;Hg^{2+},\;Cd^{2+}\;group)$. In mixed heavy metal ions, the removals of $Fe^{2+},\;Fe^{3+},\;Pb^{2+},\;Cu^{2+}$ as 0.49 m㏖/g, regardless of the existence of other heavy metal ions, were similar to the result of single heavy metal ions experiment. The removals of $Mn^{2+},\;Cd^{2+},\;Ni^{2+}$ decreased as the existence of other heavy metal ions, however, the removal of $Zn^{2+},\;Cr^{3+},\;Hg^{2+}$ increased.

A Study on Metal Expressed in Contemporary Fashion -Focusing on Women's Fashion in 1990s- (현대패션에 나타난 금속에 관한연구 -1990년대 여성복을 중심으로-)

  • 금기숙
    • Journal of the Korean Society of Costume
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    • v.45
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    • pp.161-178
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    • 1999
  • In contemporary fashion metal have used which is as the material with a sufficient potentiality of expression which is displayed by an unique characteristic involved only in metal. In this paper metal expressed in contemporary fashion is researched. The first thing the formative characteristic of metal is researched under the consideration of type technique and color of metal used in contemporary fashion. Metals such as gold silver bronze aluminum thin lead and iron are usually used in fashion and those metals are used in various types such a thread fabric board leaf a and cable. Those types of metal as above are applied to the clothing by the techniques of weaving embroidering metal leaf printing or moulding which gives the formative characteristic to the clothing. In color metal has an effect on the colors of surroundings by its smooth and unique luster and its effect of reflection and produces the visual formative characteristic through the effects of contrast. The esthetic will of metal expressed in modern fashion is researched in this study under the facts studied as above. first metal expresses the future oriented esthetic Second metal has the characteristic of attracting the attention Third metal is used as valid techniques to express the artistic formation for clothing escaping from the idea that the clothing is only for wearing. Finally metal is used as an anti-cultural tool of fighting against the existing order or spirit.

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A Study on the corrosion property by post treatment in the metal dry etch (Metal 건식각 후처리에 따른 부식 특성에 관한 연구)

  • Mun, Seong-Yeol;Kang, Seong-Jun;Joung, Yang-Hee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.747-750
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    • 2007
  • This study proposes that chlorine residue after metal etch as the source of metal corrosion, and charges should be removed by optimizing etch, PR strip and cleaning condition. Charges distributed along the metal line acts as a source of tungsten (W) plug corrosion when associated with following cleaning solution. In cleaning process after metal etch and PR strip, chemical selection is significantly important in terms of metal corrosion. Optimal corrosion preventive PH, no metal attack (choice of optimal inhibitants), high by product removal efficiency and optimal de ionized water treatment condition is critical to the metal corrosion prevention.

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The Bonding of Interstitial Hydrogen in the NiTi Intermetallic Compound

  • Kang, Dae-Bok
    • Bulletin of the Korean Chemical Society
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    • v.27 no.12
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    • pp.2045-2050
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    • 2006
  • The interstitial hydrogen bonding in NiTi solid and its effect on the metal-to-metal bond is investigated by means of the EH tight-binding method. Electronic structures of octahedral clusters $Ti_4Ni_2$ with and without hydrogen in their centers are also calculated using the cluster model. The metal d states that interact with H 1s are mainly metal-metal bonding. The metal-metal bond strength is diminished as the new metal-hydrogen bond is formed. The causes of this bond weakening are analyzed in detail.

The Bonding Strength Characteristic of the Filler Metal Powder on the TLP Bonded Region of Superalloy GTD-111DS (일방향 초내열합금 GTD-111DS에서 삽입금속 분말에 따른 천이액상확산접합부의 접합강도 특성)

  • Oh, In-Seok;Kim, Gil-Moo;Moon, Byeong-Shik
    • Journal of Welding and Joining
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    • v.25 no.5
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    • pp.45-50
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    • 2007
  • The Ni-base superalloy GTD111 DS is used in the first stage blade of high power land-based gas turbines. Advanced repair technologies of the blade have been introduced to the gas turbine industry over recent years. The effect of the filler metal powder on Transient Liquid Phase bonding phenomenon and tensile mechanical properties was investigated on the GTD111 DS superalloy. At the filler metal powder N series, the base metal powders fully melted at the initial time and a large amount of the base metal near the bonded interlayer was dissolved by liquid inter metal. Liquid filler metal powder was eliminated by isothermal solidification which was controlled by the diffusion of B into the base metal. The solids in the bonded interlayer grew from the base metal near the bonded interlayer inward the insert metal during the isothermal solidification. The bond strength of N series filler metal powder was over 1000 MPa. and ${\gamma}'$ phase size of N series TLP bonded region was similar with base metal by influence of Ti, Al elements. At the insert metal powder M series, the Si element fluidity of the filler metal was good but microstructure irregularity on bonded region because of excessive Si element. Nuclear of solids formed not only from the base metal near the bonded interlayer but also from the remained filler metal powder in the bonded interlayer. When the isothermal solidification was finished, the content of the elements in the boned interlayer was approximately equal to that of the base metal. But boride and silicide formed in the base metal near the bonded interlayer. And these boride decreased with the increasing of holding time. The bond strength of M series filler metal powder was about 400 MPa.

Heavy Metal Biosorption and its Significance to Metal Tolerance if Streptomycetes

  • Park, Jae-young;Kim, Jae-heon
    • Journal of Microbiology
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    • v.40 no.1
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    • pp.51-54
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    • 2002
  • Heavy metal adsorptions of four streptomycetes were compared with each other, Among the test strains, Streptomyces viridochromogenes showed the most efficient metal binding activity, which was carried out by cell wall as well as freeze-dried mycelium. An order of adsorption potential (zinc > copper > lead > cadmium) was observed in single metal reactions, whereas this adsorption order was disturbed in mixed-metal reactions. The metal adsorption reactions were very fast, pH dependent and culture age-independen, suggestive of a physico-chemical reaction between cell wall components and heavy metal ions. The metal tolerant stains presented the weakest adsorbing activity, indicating that the metal biosorption was not the basis of the metal tolerance.

A Study on Development of Metal Detector on Belt Conveyor in Material Plant (원료수송용 벨트컨베이어의 철편인식 장치 개발에 관한 연구)

  • Yoo, Jae-Sang
    • Proceedings of the KIEE Conference
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    • 1997.07b
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    • pp.714-716
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    • 1997
  • In order to prevent the belt from being damaged by metal pieces, we developed multicoil-type metal detection system. This detects the presence of belt clips and position of metal pieces in ores being transported on conveyor belt. In this research, our coil sensor of multicoil-type metal detection system is divided into two parts, exciting part (transmitter coil) and sensing part composed of two receiver coils. Each receiver coil has several coils in the direction of belt width. Multicoil-type metal detection system is operated by supplying a transmitter coil with electric power resources to generate magnetic field, and then the change of magnetic flux resulted from a metal piece on the conveyor be a is induced into sensing coils. We can prevent detector from failing to catch metal pieces due to high threshold level produced by steel belt clips and male the sensitivity of belt-width direction uniform by using multicoil-type metal detection system. Besides, this developed system can recognize precise position and size of metal piece. The experiments shows that our multicoil-type metal detection system has better performances than the conventional metal piece detector.

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The variation of SCC resistance in duplex stainless steel weldment (이상계 스테인레스강 용접부의 응력부식균열에 관한 연구)

  • 김충언;강춘식;김희진
    • Journal of Welding and Joining
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    • v.5 no.4
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    • pp.36-46
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    • 1987
  • The impact toughness and SCC resistance of duplex stainless steel weldment made by GTAW, GMAW and SMAW processes was studied. The impact toughness of GTA weld metal was higher than that of GMA weld metal which contained more ferrite phase than GTA weld metal. The impact toughness of SMA weld metal was the lowest due to the harmful effect of inclusions inspite of richness of more ductile austenite phase. From these facts, it can be concluded that the important factors determining the weld metal toughness were the amount of ferrite phase and the cleaness of weld metal. While the SCC resistance of SMA weld metal was lower than that of base metal and nay other weld metal, the SCC resistance of GMA and GTA weld metal was higher than that of base metal but that of all the HAZ's were lower than that of base metal. Therefore, the impact toughness and SCC resistance of GTA and GMA weldment was pretty good as long as phase ratio was propertly controlled. Although the phase ratio was controlled, SMA weld metal could not get a good combination because the lack of shielding from the environment results in a high content of inclusions in weld metal.

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A STUDY ON FRACTURE STRENGTH AND COLOR BY THE DESIGN OF METAL COPING IN CERAMO METAL CROWN (내부금속관 형태에 따른 도재전장금관의 파절강도와 도재색조에 관한 연구)

  • Lee Myung-Ho;Jeon Young-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.30 no.1
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    • pp.103-124
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    • 1992
  • The purpose of this study was to investigate the effect on the fracture strength and color of ceramic by the design of the metal coping in ceramo metal crown. In this study, four types of ceramic crowns were made for fracture strength : standard ceramo metal crown, collariess ceramo metal crown, modified ceramo metal crown, and ceramic jacket crown. And three types of disk formed-specimens were made to compare the dentin shade owing to aluminous opaque powder and palladium alloy. Fracture strength was measured by universal testing machine(Instron Co. Ltd., U.S.A) and color was measured by color and color difference meter(Yasuda Seiki Seisakusho, Ltd., Japan). The results were as follows : 1. The fracture strength of ceramic was affected significantly by the design of metal coping in ceramo metal crown. The mean fracture strength(192.0 Kg) of standard ceramo metal crown was about 1.7 times higher than that(111.5 Kg) of collarless ceramo metal crown, and about 2.8 times higher than that(67.8 Kg) of ceramic jacket crown. 2. Modified ceramo metal crown that has metal band in the labio cervical had the lowest fracture strength. 3. Lightness, yellowness and redness of the dentin fired were decreased by the metal coping.

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