| Koji Takahashi | Last modified date：2024.04.13 |
Professor /
Thermophysics and Fluid Mechanics /
Department of Aeronautics and Astronautics /
Faculty of Engineering
Presentations
| 1. | Mai HIRAKAWA, Hideaki TESHIMA, Tatsuya IKUTA, Koji TAKAHASHI, Crack Propagation Mechanism of Freeze-Dried Soybean Curds during the Rehydration Process, APS DFD 2023, 2023.11. |
| 2. | H. Teshima, T. Ueno, K. Takahashi, Three-Dimensional Observation of Three-Phase Contact Line with Precursor Film on Nanostructured Surfaces, APS DFD 2023, 2023.11. |
| 3. | H. Ishida H. Teshima, K. Takahashi, DEVELOPMENT OF AFM MEASUREMENT METHOD FOR SLIP LENGTH CONSIDERING THE EFFECT OF ELECTRIC DOUBLE LAYER FORCE, The 8th International Conference on Micro and Nano Flows, 2023.09. |
| 4. | Hideaki Teshima, Qin-Yi Li, Koji Takahashi, Thermally induced mass transfer between nanobubbles and micropancakes, The 8th International Conference on Micro and Nano Flows, 2023.09. |
| 5. | Qin-Yi Li, Kun Cheng, Kuan-Ting Cheng, Koji Takahashi, Slip flow and capillary evaporation in graphene nanochannels, 6th International Conference on Droplets, 2023.08. |
| 6. | Hideaki Teshima, Koji Takahashi, Experimental Investigation of Solid-Liquid Interfacial Phenomena at the Nanoscale, 10th US-Japan Joint Seminar on Nanoscale Transport Phenomena, 2023.07. |
| 7. | Koji Takahashi, Nanomaterials for phase change heat transfer, 13th Asian Thermophysical Properties Conference (ATPC2022), September 26-30, 2022, Sendai, Japan, 2022.09, Nanomaterials are of unique thermophysical properties and have been used in a wide variety of experimental studies aimed at significant enhancement of heat transfer performance. Many successful results have been reported, for example, selective thermal radiation of surface coatings with nanoparticles, high-thermal conductivity composites or coolants with nanoscale fillers. So far, most of their roles are to improve the conduction or radiation heat transfer. On the other hand, their applications to improve mass transfer are still in the stage of trial and error. The most well-known application is to use hydrophilic materials for preventing surface dryout at high heat flux but the underlying mechanisms of capillary motion and evaporation in nanoscale are not clarified yet, thus we have no strategy to precisely control the liquid-vapor phase change by designing artificial nanostructured surfaces. In this talk, a novel approach to enhance the convection in the evaporating meniscus on a hot surface is introduced, where the atomic-scale flatness of two-dimensional materials represented by graphene is used. Its beneficial role is the large slip length of liquid on the surface. In addition to the reviews of past reports, new experimental and theoretical results are presented for evaluating the slip flow on graphene, together with the relationship between wettability and slip length of an identical surface. The gap between ideal thermophysical property of nanomaterials and real performance of heat transfer devices is also discussed. At first, the above-mentioned surface of atomic-scale flatness is mostly dirty with contaminants and nanoparticles, which pin the three-phase contact lines and consequently influence the cooling performance. Newest nanoscale findings on the pinned or unpinned contact lines using AFM and TEM are summarized in this talk. Next, the thermal contact resistance between fibrous materials is treated, which is a difficult research target for thermal application of nanomaterials. An experimental method is presented to quantitatively evaluate the contact resistance using Raman spectroscopy. The last concern is the quality of nanomaterials and a STEM-based experimental study clearly demonstrated that the thermal conductivity of an individual nanotube depends on its structural quality. The history of nanotechnology is over 20 years but these kinds of experimental studies are still needed to increase the reliability of heat transfer devices with nanomaterials and nanostructures.. |
| 8. | Koji Takahashi, Gas molecules at solid-liquid interfaces, The 7th International Conference on Micro and Nano Flows (MNF 2021), 2021.05, [URL]. |
| 9. | Koji Takahashi, Towards reliable cooling technology from nanoscale transport phenomena, I2CNER THRUST WORKSHOP: SCIENCE AND TECHNOLOGY FOR CARBON-NEUTRALITY, 2021.01. |
| 10. | Nanobubble dynamics during merging revealed using in-situ liquid cell electron microscopy. |
| 11. | Non-diffusive molecular transport in graphene liquid cells. |
| 12. | Raman optothermal methods to measure interfacial thermal conductance of low-dimensional materials. |
| 13. | Raman optothermal methods to measure interfacial thermal conductance of low-dimensional materials. |
| 14. | Nanobubble dynamics studied using in-situ liquid cell electron microscopy. |
| 15. | In-situ electron microscopic study of effect of temperature on nanobubble generation. |
| 16. | Yoko Tomo, Ryo Matsushita, Qin-Yi Li, Tatsuya Ikuta, Koji Takahashi, Morphology of Water inside CNTs Depending on Wettability, The Second Pacific Rim Thermal Engineering Conference (PRTEC2019), 2019.12. |
| 17. | Hideaki Teshima, Naoto Nakamura, Yasuyuki Takata, Koji Takahashi, Mobility of Micropancakes on Adsorbed Gas Layers, The Second Pacific Rim Thermal Engineering Conference (PRTEC2019), 2019.12. |
| 18. | Sota Hirokawa, Hideaki Teshima, Pablo Solis Fernandez, Hiroki Ago, Qinyi Li, Koji Takahashi, Nanoscale observation of three-phase contact line using graphene liquid cells, The 30th International Symposium on Transport Phenomena (ISTP30), 2019.11, Revealing nanoscale dynamics of three-phase contact line promotes practical application such as nano-channels and micro heat transfer devices. However, there are still many unexplained phenomena that are obstacles to establish precise models. Thus, in order to expand knowledge of three-phase contact line, further investigation near the phase interfaces are desirable. In this study, we used liquid cell electron microscopy that enables us to investigate in-situ liquid dynamics with nanoscale spatial resolution. We prepared graphene liquid cells that give the highest resolution in liquid cells and observed three-phase contact line consisting of confined water and nanobubbles in real time using transmission electron microscopy (TEM). In our samples, nanobubbles, smaller than a few hundred nanometers in diameter, scattered around and thin water rings surrounded them. During the observation for several tens of seconds, nanobubbles deformed their shapes, which allowed us to see the movements of three-phase contact line. We elucidated the mechanism of this movement by considering the influences of electron beam irradiation on water and the graphene layers.. |
| 19. | Qinyi Li, Toshiaki Kato, Xiulin Ruan, Koji Takahashi, Record-high Thermoelectric Performance of Graphene, The 12th Asian Thermophysical Properties Conference (ATPC2019), 2019.10. |
| 20. | Koji Takahashi, Yoko Tomo, Ryo Matsushita, Tatsuya Ikuta, Qin-Yi Li, Water confined in hydrophilic and hydrophobic inner spaces of cup-stacked carbon nanotubes, 30th International Conference on Diamond & Carbon Materials 2019, 2019.09. |
| 21. | Koji Takahashi, TEM and AFM studies of bubble nucleation and growth near solid-liquid interfaces, 2019 Micro and Nanoscale Phase Change Heat Transfer, Gordon Research Conference, 2019.02, New experimental techniques to investigate nanoscale bubbles and droplets are explained, using TEM and AFM. AFM is of the highest spatial resolution and its feedback control of tip tapping enables us to obtain the accurate shape of nanobubbles at the solid-liquid interface. TEM requires ultra-high vacuum environment but utilization of nano liquid cell enables us to image the liquid-gas interface in nanoscale. By using these techniques, some key issues for generation and growth of interfacial nanobubbles have been understood.. |
| 22. | Koji Takahashi, Nanomaterials and Nanobubles for Heat Transfer, 6th UK Japan Engineering Education League Workshop 2018, 2018.09. |
| 23. | Koji Takahashi, BUBBLES AND DROPLETS AT THE INITIAL STAGE OF NUCLEATION: RECENT ADVANCES IN EXPERIMENTAL TECHNIQUES, 16th International Heat Transfer Conference, 2018.08. |
| 24. | Koji Takahashi, Interfacial Nanobubbles on Biphilic Surfaces, ASME 2018 16th International Conference on Nanochannels, Microchannels and Minichannels (ICNMM2018), 2018.06. |
| 25. | Koji Takahashi, Qinyi Li, Xing Zhang, Thermophysical measurement methods for individual nanomaterials and control of nanoscale thermal transport, 2018 I2CNER Annual Symposium: challenges in thermal science towards a sustainable society, 2018.01. |
| 26. | Masahiro Narasaki, Haidong Wang, Yasuyuki Takata, Tatsuya Ikuta, Koji Takahashi, Experimental Approach to Control the Thermal Conductivity of Single-Layer Graphene by Fluorination, ASME 2017 International Mechanical Engineering Congress and Exposition, 2017.11. |
| 27. | Yoko Tomo, Koji Takahashi, Tatsuya Ikuta, Yasuyuki Takata, Direct Observation of Heterogeneous Bubble Nucleation in Nanoscale, ASME International conference on nanochannels, microchannels, and minichannels, 2017.08. |
| 28. | Li Q Y, Zhang X, Takahashi K, Dual-mode Raman method to measure thermal transport properties of 2D materials and van der Waals heterostructures, The 9th US-Japan Joint Seminar on Nanoscale Transport Phenomena, 2017.07. |
| 29. | Koji Takahashi, AFM and TEM studies on nanobubbles, The 9th US-Japan Joint Seminar on Nanoscale Transport Phenomena, 2017.07. |
| 30. | Masahiro Narasaki, Haidong Wang, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Thermal Transport of Fluorinated Single-Layer Graphene, The 9th World Conference on Experimental Heat Tranfer, Fluid Mechanics and Thermodynamics, 2017.06. |
| 31. | Hideaki Teshima, Takashi Nishiyama, Koji Takahashi, EXPERIMENTAL STUDY ON THE COALESCENCE OF INTERFACIAL NANOBUBBLES, The 27th International Symposium on Transport Phenomena, 2016.09. |
| 32. | Masahiro Narasaki, Jin Miyawaki, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, THERMAL TRANSPORT IN MULTI-WALLED CARBON NANOTUBE AND CARBON NANOFIBER DEFECTED BY FOCUSED ION BEAM, The 27th International Symposium on Transport Phenomena, 2016.09. |
| 33. | Yoko Tomo, Koji Takahashi, Takashi Nishiyama, Tatsuya Ikuta, Yasuyuki Takata, TEM Study on Phase Change in a Nano Liquid Cell, 5th Micro and Nano Flows Conference, 2016.09. |
| 34. | Koji Takahashi, Yasuyuki Takata, Takashi Nishiyama, 山田 寛, Experimental Study of Nanobubbles and Nanodroplets on Hydrophilic/Hydrophobic Combined Surfaces, 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT2016), 2016.07. |
| 35. | Masahiro Narasaki, Koji Takahashi, Jin Miyawaki, Yasuyuki Takata, IN SITU THERMAL CONDUCTANCE MEASUREMENT OF AN INDIVIDUAL CARBON NANOFIBER DEFECTED BY FOCUSED ION BEAM, 7th European Thermal-Sciences Conference, EUROTHERM 2016, 2016.06. |
| 36. | Masayuki Yamada, Biao Shen, Hongbin He, Kento Furutsato, Sumitomo Hidaka, Masamichi Kohno, Koji Takahashi, Yasuyuki Takata, Boiling Heat Transfer Enhancement with Hydrophobic Islands at Sub-Atmospheric Pressures, The First Pacific Rim Thermal Engineering Conference, 2016.03. |
| 37. | Alexandros Askounis, Yutaka Yamada, Tatsuya Ikuta, Koji Takahashi, Yasuyuki Takata, Khellil Sefiane, Uncovering the Potential of CNTS as Nano- Heat Pipes, The First Pacific Rim Thermal Engineering Conference, 2016.03. |
| 38. | Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Yasuyuki Takata, Khellil Sefiane, Surface Wettability Tuning for Submicron-Scale Condensation and Evaporation, The First Pacific Rim Thermal Engineering Conference, 2016.03. |
| 39. | Seigo Nakajima, Kazuma Nomoto, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Electron Thermal Microscopy of Suspended MWCNT, The First Pacific Rim Thermal Engineering Conference, 2016.03. |
| 40. | Ayumu Iwanaga, Takashi Nishiyama, Tatsuya Ikuta, Koji Takahashi, Yasuyuki Takata, Yutaka Yamada, Stability of intefacial nanobubble depends on substrate, The First Pacific Rim Thermal Engineering Conference, 2016.03. |
| 41. | Koji Takahashi, Yusuke Kuwada, Tatsuya Ikuta, MEASURING THE THERAL CONTACT RESISTANCE WITHOUT SURFACE ROUGHNESS, The 26th International Symposium on Transport Phenomena, 2015.09. |
| 42. | Koji Takahashi, Takashi Nishiyama, Yasuyuki Takata, Generation and Metastability of Interfacial Nanobubbles, 14th UK Heat Transfer Conference 2015, 2015.09. |
| 43. | Masahiro Narasaki, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Experimental study on thermal transport of an artificially-defected multi-walled carbon nanotube, XXIV International Materials Research Congress, 2015.08. |
| 44. | Koji Takahashi, Kazuma Nomoto, Tatsuya Ikuta, Temperature Mapping on a Suspended Carbon Nanotube Using Electron Thermal Microscopy, IEEE NANO 2015, 15th INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY, 2015.07. |
| 45. | Koji Takahashi, Yutaka Yamada, Takashi Nishiyama, Tatsuya Ikuta, Yasuyuki Takata, SUBMICRON-SCALE WETTABILITY CONTROL BY USING FOCUSED ION BEAM IRRADIATION TO FOPA-SAM, International Symposium on Micro and Nano Technology, ISMNT-5, 2015.05. |
| 46. | Yutaka Yamada, Koji Takahashi, Yasuyuki Takata, HYDROPHOBIC-HYDROPHILIC SURFACE PATTERNED BY FIB TO REVEAL NUCLEATION MECHANISMS, 9th International Conference on Boiling and Condensation Heat Transfer, 2015.04. |
| 47. | Koji Takahashi, Takashi Nishiyama, Yutaka Yamada, Yasuyuki Takata, Reliability of AFM Measurement of Nanobubbles on Solid Liquid Interface, Gordon Research Conference Micro & Nanoscale Phase Change Heat Transfer, 2015.01. |
| 48. | Koji Takahashi, Yutaka Yamada, Takashi Nishiyama, Tatsuya Ikuta, Thermal Resistance of van der Waals Contacts for Nanoscale Thermometry, Material Science and Engineering (MSE 2014), 2014.09. |
| 49. | Masahiro Narasaki, Hiroyuki Hayashi, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Study on heat conduction of defective MWNT using focused ion beam irradiation, 20th European Conf. Thermophysical Properties (ECTP2014), 2014.09. |
| 50. | Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Yasuyuki Takata, Wettability-driven water condensation in micron- and submicron-scale, 15th International Heat Transfer Conference (IHTC-15), 2014.08. |
| 51. | Koji Takahashi, Yutaka Yamada, Takashi Nishiyama, Yasuyuki Takata, Experimental Investigation of Nanodroplets and nanobubbles, 8th US-Japan Joint Seminar on Nanoscale Transport Phenomena, 2014.06. |
| 52. | Koji Takahashi, Hiroyuki Hayashi, Characterization of Thermal Transport in Multiwalled Carbon Nanotube Using FIB Irradiation, Fourteenth InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 201, 2014.05. |
| 53. | Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Yasuyuki Takata, Growth and Coalescence of Condensed Microdroplets on Graphite Surface, 5th International Conference on HEAT TRANSFER AND FLUID FLOW IN MICROSCALE, 2014.04. |
| 54. | Kazunari Tsuru, Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Experimental Study on Thermal Contact Resistance of Multi-Walled Carbon Nanotubes, ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass , 2013.12. |
| 55. | Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Yasuyuki Takata, Submicron Scale Condensation on Hydrophobic and Hydrophilic Surfaces , ASME 2013 International Mechanical Engineering Congress & Exposition (IMECE2013), 2013.11. |
| 56. | Koji Takahashi, Microfabrication techniques for nanoscale heat transfer, The 4th International Symposium on Micro and Nano Technology (ISMNT-4), 2013.10. |
| 57. | Koji Takahashi, Anisotropic Thermal Transport and Metrological Application of Multiwalled Carbon Nanotube, The 10th Asian Thermophysical Properties Conference (ATPC2013), 2013.10. |
| 58. | Juo Amano, Koji Takahashi, Fluctuating Electromagnetics for Thermal Contact Conductance, 8th International Conference on Surfaces, Coatings and NanoStructured Materials (NANOSMAT), 2013.09. |
| 59. | Koji Takahashi, Hiroyuki Hayashi, Masahiro Narasaki, Tatsuya Ikuta, Takashi Nishiyama, Experimental Study on Heat Conduction in a Defected Multi-walled Carbon Nanotube, 8th International Conference on Surfaces, Coatings and NanoStructured Materials (NANOSMAT), 2013.09. |
| 60. | Koji Takahashi, Experimental Techniques using Nano Hot-film for Micro/Nanoscale Heat Transfer, ASME 11th Int. Conf Nanochannels, Microchannels, Minichannels, 2013.06. |
| 61. | Hiroyuki Hayashi, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Experimental characterization of heat conduction in multi-walled carbonnanotubes, 2013 MRS Spring Meeting & Exhibit, 2013.04. |
| 62. | Yutaka Yamada, Jun Hirotani, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Quantitative Evaluation of Carbon Nanotube Fin for Chip Cooling, 23rd International Symposium on Transport Phenomena, 2012.11. |
| 63. | Juo Amano, Jun Hirotani, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Carbon Nanotube Temperature Profiler using Platinum Hot Film, 23rd International Symposium on Transport Phenomena, 2012.11. |
| 64. | Hiroyuki Hayashi, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Individual Measurement of Thermal Conductivity of Damaged MWCNT, 3rd International Forum on Heat Transfer, 2012.11. |
| 65. | Jun Hirotani, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Thermal Boundary Resistance of Nanoscale van der Waals Contacts between a Carbon Nanotube End and Solid Surfaces, 3rd International Forum on Heat Transfer, 2012.11. |
| 66. | Yutaka Yamada, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Effect of Nanoscale Stracture on Thermal Contact Resistance of Carbon Nanotubes, ASME 2012 Summer Heat Transfer Conference, 2012.07. |
| 67. | Hiroyuki Hayashi, Tatsuya Ikuta, Takashi Nishiyama, Koji Takahashi, Thermal Conductivity of Partially-Amorphized Individual Carbon Nanotube, EIGHTEENTH SYMPOSIUM ON THERMOPHYSICAL PROPERTIES, 2012.06. |
| 68. | Study on NEMS fluidic sensor using carbon nanotubes. |
| 69. | Experimental Study on Amorphous Carbon Nanostructure. |
| 70. | Research for Ultrasensitive Thermal Sensor with CNT Fins. |
| 71. | Development Study of 100?m-order Solid Rocket for Pico Satellite Application. |
| 72. | Study on Local Heat Transfer of Nano Fluidic Sensor. |
| 73. | Catalytic Porous Microchannel for hydrogen Peroxide MEMS Thruster. |
| 74. | Numerical Study on Nano Thermal Sensor with Ultra Fine Fins. |
| 75. | CONTEMPORARY TECHNOLOGY AND APPLICATION OF MEMS ROCKET. |
| 76. | Optical study of the SWNT dispersion after dielectrophoresis. |
| 77. | POROUS SILICON AS A SUPERHYDROPHOBIC MICROCHANNEL SURFACE Koji Takahashi The 1st International Symposium on Micro & Nano Technology, 14-17 March, 2004, Honolulu, Hawaii, USA, 2004. |
| 78. | HEAT CONDUCTION OF SILICON DIOXIDE THIN FILM LAYERS FOR MEMS THRUSTER Hideyo Ebisuzaki, Xing Zhang, Motoo Fujii and Koji Takahashi The 1st International Symposium on Micro & Nano Technology, 14-17 March, 2004, Honolulu, Hawaii, USA, 2004. |
| 79. | SILICON-FREE MICRO RESITOR ARRAY FOR SMART HOT FILM Koji Takahashi The 1st International Symposium on Micro & Nano Technology, 14-17 March, 2004, Honolulu, Hawaii, USA, 2004. |
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