2005 Fiscal Year Final Research Report Summary
Ultrasound separation and measurements of materials from molecules to particles
| Project/Area Number |
16350041
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Analytical chemistry
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
OKADA Tetsuo Tokyo Institute of Technology, Department of Chemistry, Professor, 大学院・理工学研究科, 教授 (20183030)
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| Co-Investigator(Kenkyū-buntansha) |
HARADA Makoto Tokyo Institute of Technology, Department of Chemistry, Research Associate, 大学院・理工学研究科, 助手 (60313326)
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| Project Period (FY) |
2004 – 2005
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| Keywords | ultrasound / particles / flow properties / separation |
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| Research Abstract |
The followings have been studied to establish novel methods for particle separation.
1. Design and fabrication of separation channels, which allow the accumulation of particles with an aid of an electric field followed by acoustic discrimination
Basic techniques have been established and the effectiveness of the electrical accumulation has been confirmed. The acoustic behavior of particles has been quantitatively evaluated with designed channels. However, separation of different types of particles has proven difficult because of interparticle interaction
2. Fundamental researches to distinguish particles such as ion-exchange resin beads in terms of their swelling states
Ion-exchange resins with different counterions can be discriminated with an acoustic field. Their behavior is determined basically by the compressibility rather than by density of particles. Thus, ion-exchange phenomena can be evaluated from viewpoint different from those of conventional approaches.
3. Separation of heavy pa
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rticles such as metal particles on the basis of their behavior in an acoustic field.
An acoustic filed recognizes a metal having high density but low compressibility as a light metal, but that having low density but high compressibility as a heavy metal ; iron is an example of the former, while aluminum is an example of the latter. Since a mechanism coming from the density is more largely contribute to the entire separation mechanism, mutual separation is difficult. However, the adjustment of acoustic field strength has allowed rough fractionation of iron and its alloys having similar density.
Application of flow properties to molecular separation has been investigated. The properties of a flow and molecular diffusion therein were quantitatively characterized in 2004. According to the mechanism revealed in our research, materials introduced into the lamina flow behave as diffusive or nondiffusive mass, which is determined by the length and radius of the capillary and the diffusion coefficients of the masses under study. This mechanism cannot act on dissolved molecules, which behave as diffusive solutes under almost any conditions. However, we can give them nondiffusive characters, and separate them using their interactions with molecular aggregates, such as micelles and vesicles. This phenomenon has been quantitatively evaluated, and separation of organic mall molecules and inorganic ions has been demonstrated with simple passage through an open capillary. Less
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