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DONG HAI WANG Last modified date:2018.05.16

Assistant Professor / Thermal engineering
Department of Mechanical Engineering
Faculty of Engineering




E-Mail
Homepage
http://www.mech.kyushu-u.ac.jp/~hmt/HMT_lb_en.html
Homepage of our Heat and Mass Transfer Lab .
Academic Degree
PhD degree of Mechanical Engineering
Field of Specialization
Heat and Mass Transfer
Outline Activities
My research is now focused on the MEMS technology, biothermal science, measurement of thermal properties of nanomaterials and study of heat conduction mechanisms at nanoscales. My education work is to teach and guide both undergraduate and graduate students in their research related with heat and mass transfer. I serve and contribute to the societies through participating different academic activities of Heat Transfer Society of Japan and Japan Society of Mechanical Engineers.
Research
Research Interests
  • My research is now focused on the measurement of thermal properties of nanomaterials (carbon nanotubes, graphene, nanofilms, etc) using MEMS technology, study of heat conduction mechanisms at nanoscales, biothermal science.
    keyword : MEMS technology, thermal properties of nanomaterials, biothermal science
    2014.01~2018.08.
Current and Past Project
  • Now the DNS sequencing market has become more than 680 billion yen. For the third generation sequencing technology, the Single Molecule Real Time Sequencing (SMRT) has been developed. In order to realize SMRT, this project aims to suspend single layer of graphene (0.334nm thickness) with a nanopore for a single DNA molecule to pass through. The base order of DNA molecule can be decided by detecting the electrical current signal change of the graphene. This method has much higher S/N ratio than the present 25nm thick graphene/SiNx membrane.
  • Graphene has ultra-high thermal conductivity, it has a great potential to be used as heat spreader for electronic devices. However, graphene has to be supported on substrate for applications because of its one-atom thickness. The interaction between the graphene and substrate may significantly reduce its thermal conductivity and affect the performance as heat spreader. In order to understand the interface effect of graphene and develop effective graphene heat spreaders, a T-type sensor is developed in this research for measuring the heat transport in graphene.
Academic Activities
Papers
1. Haidong Wang, Dingshan Zheng, Xing Zhang, Hiroshi Takamatsu and Weida Hu, Benchmark characterization of the thermoelectric properties of individual single-crystalline CdS nanowires by a H-type sensor, RSC Advances, DOI: 10.1039/c7ra02734f, 7, 25298-25304, 2017.08.
2. Haidong Wang, Shiqian Hu, Koji Takahashi, Xing Zhang, Hiroshi Takamatsu and Jie Chen, Experimental study of thermal rectification in suspended monolayer graphene, Nature Communications, doi:10.1038/ncomms15843, 8, 15843, 2017.06.
3. DONG HAI WANG, Xing Zhang, Hiroshi Takamatsu, Ultraclean suspended monolayer graphene achieved by in situ current annealing, Nanotechnology, 28, 045706, 2016.12.
4. DONG HAI WANG, Kosaku Kurata, Takanobu Fukunaga, Hiroshi Takamatsu, Xing Zhang, Simultaneous measurement of electrical and thermal conductivities of suspended monolayer graphene, Journal of Applied Physics, 119, 244306, 2016.08.
5. DONG HAI WANG, Kosaku Kurata, Takanobu Fukunaga, Hiroshi Takamatsu, Xing Zhang, A general method of fabricating free-standing, monolayer graphene electronic device and its property characterization, Sensors and Actuators A: Physical, 247, 24-29, 2016.05.
6. DONG HAI WANG, Kosaku Kurata, Takanobu Fukunaga, Hiroshi Takamatsu, Xing Zhang, Width depended intrinsic thermal conductivity of suspended monolayer graphene, International Journal of Heat and Mass Transfer, 105, 76-80, 2017.01.
7. DONG HAI WANG, Kosaku Kurata, Takanobu Fukunaga, Hiroshi Takamatsu, Xing Zhang, Tatsuya Ikuta, Koji Takahashi, Takashi Nishiyama, Hiroki Ago, Yasuyuki Takata, In-situ measurement of the heat transport in defect-engineered free-standing single-layer graphene, Scientific Reports, DOI: 10.1038/srep21823, 6, 21823, 2016.02, Utilizing nanomachining technologies, it is possible to manipulate the heat transport in graphene by introducing different defects. However, due to the difficulty in suspending large-area single-layer graphene (SLG) and limited temperature sensitivity of the present probing methods, the correlation between the defects and thermal conductivity of SLG is still unclear. In this work, we developed a new method for fabricating micro-sized suspended SLG. Subsequently, a focused ion beam (FIB) was used to create nanohole defects in SLG and tune the heat transport. The thermal conductivity of the same SLG before and after FIB radiation was measured using a novel T-type sensor method on site in a dualbeam system. The nanohole defects decreased the thermal conductivity by about 42%. It was found that the smaller width and edge scrolling also had significant restriction on the thermal conductivity of
SLG. Based on the calculation results through a lattice dynamics theory, the increase of edge roughness and stronger scattering on long-wavelength acoustic phonons are the main reasons for the reduction in thermal conductivity. This work provides reliable data for understanding the heat transport in a defective SLG membrane, which could help on the future design of graphene-based electrothermal devices..
8. DONG HAI WANG, Kosaku Kurata, Takanobu Fukunaga, Hiroshi Takamatsu, Xing Zhang, Tatsuya Ikuta, Koji Takahashi, Takashi Nishiyama, Hiroki Ago, Yasuyuki Takata, A simple method for fabricating free-standing large area fluorinated single-layer graphene with size-tunable nanopores, Carbon, http://dx.doi.org/10.1016/j.carbon.2015.12.070, 99, 564-570, 2016.01, As a solid-state membrane with only one-atom thickness, nano-porous graphene has attracted intense attention in many critical applications. Here, the key challenge is to suspend a single-layer graphene (SLG) and drill nanopores with precise dimensions. Here, we report a simple and reliable route for making suspended fluorinated SLG with size-tunable nanopores. Our method consists of two steps: 1. a free-standing SLG ribbon was created between two gold pads after deep dry etching of silicon substrate by xenon difluoride. The SLG was fluorinated by 5e13%. Superior to the normal wet etching method, the dry etching process is much simpler and results in less hole-defect and edge deformation. A large area fluorinated SLG can be suspended due to the sufficient etch depth. 2. a focused ion beam was introduced to drill nanopores in graphene with an initial diameter around 20 nm. Followed by an electron beam induced carbon deposition, the diameter of nanopore was gradually decreased to sub-10 nm. By changing the deposition time, the size of nanopore can be precisely controlled. High-cost transmission electron microscope is no longer needed. Our method provides a simple and effective way for preparing free-standing fluorinated SLG ribbon suitable for single-molecule detection..
Presentations
1. Haidong Wang, Xing Zhang, Hiroshi Takamatsu and Koji Takahashi, Effective thermal rectification in suspended monolayer graphene, 16th International Heat Transfer Conference, 2018.08.
2. Haidong WANG, Takanobu FUKUNAGA, Kosaku KURATA, Hiroshi TAKAMATSU, 架橋単層カーボンナノチュブの熱伝導解析, 第55回 日本伝熱シンポジウム, 2018.05.
3. Haidong Wang, Xing Zhang, Hiroshi Takamatsu and Koji Takahashi, Thermal rectification in suspended monolayer graphene, 9th US-Japan Joint Seminar on Nanoscale Transport Phenomena, 2017.07.
4. Haidong Wang, Hiroshi Takamatsu, Koji Takahashi and Xing Zhang, 単層グラフェンの熱流束制御技術に関する研究, 第65回応用物理学会春季学術講演会, 2018.03.
5. DONG HAI WANG, Hiroshi Takamatsu, Xing Zhang, Width-dependent thermal conductivity of suspended single- layer graphene, 1st Asian Conference on Thermal Science , 2017.03.
6. DONG HAI WANG, Koji Takahashi, Hiroshi Takamatsu, Xing Zhang, Highly sensitive charge mobility of suspended monolayer graphene, 6 th International Symposium on Micro and Nano Technology, 2017.03.
7. DONG HAI WANG, Hisada Kosuke, Kosaku Kurata, Fukunaga Takanobu, Hiroshi Takamatsu, Feasibility of using micro-beam sensor for gas detection, size effect on heat conduction to gases, 1st Pacific Rim Thermal Engineering Conference , 2016.03.
8. DONG HAI WANG, Hiroshi Takamatsu, Koji Takahashi, Xing Zhang, Effect of nanohole defect on the thermal conductivity of free-standing single-layer graphene
, 11th Asian Thermophysical Properties Conference, ATPC2016, 2016.10, In this paper, we report thermal conductivity of free-standing single-layer graphene measured using a T-type sensor method. After measuring a defect-free graphene, we examined the effect of nanoholes created in situ using a focused ion beam. The thermal conductivity was ~2300 Wm-1K-1 at room temperature and decreased as temperature increased. It decreased by about 42% after creating the nanoholes. The lattice dynamics theory indicated that the decrease was a result of the increase of edge roughness and stronger scattering on long-wavelength acoustic phonons..
9. DONG HAI WANG, Hiroshi Takamatsu, Width dependent thermal conductivity of suspended monolayer graphene, The Eighth KAIST-Kyushu University Joint Workshop 2016, 2016.09, As the thinnest membrane, graphene has an ultra-high thermal conductivity over 3000 W/mK. Phonons are the main heat carriers in graphene. Different from the bulk-size material, a significant size effect exists in graphene, reflecting the unique phonon transport in two-dimensional materials. Here, we fabricated four suspended graphene samples bridged between a thin film sensor and heat sink. The sensor was used as a DC current heater and precise thermometer at the same time. The average temperature difference of sensor with and without graphene was proportional to the thermal conductivity of sample. Comparing the measured temperature difference with the thermal analysis result, the thermal conductivity of graphene could be calculated. The result demonstrated that the wide graphene had larger thermal conductivity than the narrow sample. The phonon confinement at the lateral boundaries was the underlying mechanism for the width dependence. Narrow graphene imposed more limitation on the phonon transport and reduced the thermal conductivity accordingly..
10. DONG HAI WANG, Kosaku Kurata, Hiroshi Takamatsu, Takanobu Fukunaga, Thermal conductivity of suspended monolayer graphene measured by a T-type sensor, 第53回日本伝熱シンポジウム, 2016.05, The thermal conductivity of a free-standing monolayer graphene ribon was measured by a T-type sensor method. A 10μm long gold nanofilm was suspended and used as a precise thermometer. A 2μm wide monolayer graphene ribbon was clamped to the sensor in the middle. By comparing the average temperature of sensor with and without graphene, its thermal conductivity could be calculated. The result indicates a value of 2300 W/mK at room temperature, decreasing as the temperature increases..
11. DONG HAI WANG, Kento Inui, Takanobu Fukunaga, Kosaku Kurata, Hiroshi Takamatsu, Measuring thermal conductivity of gases and liquids ranged from 0.03 to 0.6 w/(m k) using a single micro-beam sensor, 日本熱物性学会, 2015.10, The present work demonstrated the measurement of air and six kinds of liquids including water using a single sensor. The measured thermal conductivity ranged from 0.03 to 0.6 W/(mK) agreed well with literature values within 5 % error..
12. DONG HAI WANG, Kento Inui, Takanobu Fukunaga, Kosaku Kurata, Hiroshi Takamatsu, Measurement of liquid thermal conductivity using a micro-beam MEMS sensor, 日本伝熱学会, 2015.06, A micro-beam MEMS sensor was designed for measuring the thermal conductivity of a microliter liquid sample. The MEMS sensor serves as a precise Joule heater and a thermometer at the same time..
Membership in Academic Society
  • Japan Society of Mechanical Engineers (JSME)
  • Heat Transfer Society of Japan (HTSJ)
Educational
Educational Activities
Teach and guide both undergraduate and graduate students in their major courses, experiment and research. Assisting the experiment course “Mechanical Engineering experiment No. 2” (B4 students). Teach the Heat and Mass Transfer Class for the G30 students. Hold English discussion seminar for both undergraduate and graduate students.
Other Educational Activities
  • 2018.03.
  • 2017.03.
  • 2015.03.
  • 2014.07.