| Project/Area Number |
15K13553
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Biological physics/Chemical physics/Soft matter physics
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| Research Institution | Oita University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
後藤 善友 別府大学短期大学部, その他部局等, 教授 (60290657)
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| Research Collaborator |
Orihara Hiroshi 北海道大学大学院, 工学研究科, 教授 (30177307)
Hidaka Yoshiki 九州大学大学院, 工学研究院, 教授 (70274511)
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2017: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2015: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | レオロジー / 液晶 / 電気対流 / 液晶電気対流 / 散逸構造 |
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| Outline of Final Research Achievements |
An electrical convection occurs in a nematic liquid crystal under an electric field. By increasing the electric voltage, the convection becomes turbulent states. The are two kinds of turbulent states, so called Dynamic Scattering Mode 1 (DSM1) and DMS2. Only in the DSM2 state, there are a great number of disclinations that are singularity of director field. In order to clarify the differences in rheological properties between the two states, we measured the viscosity of the liquid crystal in the both turbulent states. Unfortunately, we could not find the differences due to the limitation of rheometer. However, we found a very interesting phenomenon that the apparent viscosity in the DSM2 state becomes negative and a spontaneous flow arises. This is a first experimental report for the negative viscosity in normal materials. The discovery of the negative viscosity is quite valuable in the field of material sciences.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で最も学術的に意義がある成果は，液晶電気対流の乱流状態において見かけの粘性が負になる事を発見したことである。粘性が負になる現象は，大腸菌溶液において大腸菌がほぼ一方向に泳ぐ事によって起きることがわかっているが，通常の物質で粘性が負になることは初めての発見である。粘性が負になるという事は，自発的な流れが起きることであるので，液晶電気対流を例えば平行平板に入れて発生させると，一方の板が勝手に移動するのでモーターとして利用できることになる。複雑な仕掛けなして電場を印加させるだけでモーターを作ることが可能になるので，マイクロマシンへの応用が期待できる。
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