Xinwei Wang

Associate Professor

Department of Mechanical Engineering
Walter Scott Engineering Center
The University of Nebraska at Lincoln
Lincoln, NE 68588-0656

Phone:(402) 472-3089
Fax:(402) 472-1465
E-mail: xwang3@unl.edu

Laboratory Web Site:

Micro/Nanoscale Thermal Science Laboratory

Education:

Research Interests:

Thermal Transport in Nanoscale and Nanostructured Materials

Thermal transport in nanomaterials can be very different from that in bulk materials due to the strong boundary scattering of energy carriers (photons or free electrons). In our laboratory, different numerical methods and experimental techniques are employed to study the nature thermal transport in nanomaterials and the underlying physics behind the phenomenon. Research is focused on characterizing the thermophysical properties of carbon nanotubes, and conductive and nonconductive nanofibers with contact and noncontact techniques. Research also is being conducted to explore the thermal transport in single-wall silicon nanotubes.

Highly Controlled Growth of Nanowires and Nanotubes

Objective: to fabricate nanotubes and nanowires with desired alignment and shapes via in situ unique force control. A CVD System with different gas precursors has been established in our laboratory to make carbon nanotubes and nanofibers.

Laser-Assisted Nanomanufacturing

Laser-assisted nanomanufacturing is an intense nanoscale thermal process that cannot be well described by continuum approaches. Large-scale molecular dynamics (MD) simulations are being conducted in our laboratory to answer critical questions such as (1) how the nanoscale thermal transport and phase change drive atoms to form nanostructures/patterns on the sample surface, (2) how and to what extent the nanoscale thermal stress affects the structure of the material, and (3) how the thermally induced instability influences the surface nanostructure and the spatial resolution of nanopatterns.

Research Facilities

1.Currently a super parallel computer, named 'Prarie Wind', has been established in Dr Wang's laboratory. This computer consists of a cluster of 36 fast Athlon XP processors, 36.5 GB memory, and 2.88 TB hard disk. Large scale parallel MD simulation is being conducted to explore the thermal and mechanical behaviors of materials in nanomanufacturing.
2.Continuous and pulsed lasers.
3.Picosecond-resolution high-bandwidth oscilloscope.

Research Support

1. Department of Mechanical Engineering and College of Engineering and Technology at UNL: Start-up Fund.
2. NSF: Nanoscale Exploratory Research (NER).
3. Layman Award, UNL.
4. Faculty Seed Grant, Research Council of UNL.

Graduate student recruitment:

If you can work hard and have interest in pursuing your graduate study in Dr Wang's laboratory, please contact him with your research interest and academic background.

Publications:

Journals:

14. X. Wang, 2005, "Large-Scale Molecular Dynamics Simulation of Surface Nanostructuring with Laser-Assisted Scanning Tunneling Microscope," Journal of Physics D: Applied Physics.
13. X. Wang, Z. Zhong and J. Xu, 2005, "Non-Contact Thermal Characterization of Individual Multi-Wall Carbon Nanotubes," Journal of Applied Physics, Vol. 97, pp. 064302:1-5. Also selected in the Journal of Nanoscale Science and Technology, March 14, 2005.
12. Z. Zhang, X. Wang and J. Xu, 2004, "Equilibrium Molecular Dynamics Study of Phonon Thermal Transport in Nanomaterials," Numerical Heat Transfer B, Vol. 46, pp. 429-446.
11. X. Wang, 2004, "Thermal and Thermomechanical Phenomena in Laser Copper Interaction," ASME Journal of Heat Transfer, Vol. 26, pp. 355-364.
10. X. Wang, X. Xu, 2002, "Nanoparticles Formed in Picosecond Laser Materials Interaction," ASME Journal of Heat Transfer (in review).
9. X. Wang, X. Xu, 2003, "Molecular Dynamics Simulation of Thermal and Thermomechanical Phenomena in Picosecond Laser Material Interaction," International Journal of Heat and Mass Transfer, Vol. 46, pp. 45-53.
8. X. Wang, X. Xu, 2002, "Thermoelastic Wave in Metal Induced by Ultrafast Laser Pulses," Journal of Thermal Stress Vol. 25, pp. 457-473.
7. X. Wang, X. Xu, 2002, “Molecular Dynamics Simulation of Heat Transfer and Phase Change during Laser Material Interaction,” ASME Journal of Heat Transfer Vol. 124, pp. 264-274.
6. X. Wang and X. Xu, 2001, “Thermoelastic Wave Induced by Pulsed Laser Heating,” Applied Physics A, Vol. 73, pp. 107-114.
5. X. Wang, H. Hu and X. Xu, 2001, “Photo-Acoustic Measurement of Thermal Conductivity of Thin Films and Bulk Materials,” ASME Journal of Heat Transfer, Vol. 123, pp. 138-144.
4. X. Wang, X. Xu and S. U. S. Choi, 1999, “Thermal Conductivity of Nanoparticle-Fluid Mixture,” AIAA. Journal of Thermophysics and Heat Transfer, Vol. 13, No. 4, pp. 474-480.
3. H. Hu, X. Wang and X. Xu, 1999, “Generalized Theory of Photo Acoustic Effect with a Multilayer Material,” Journal of Applied Physics, Vol. 86, No. 7, pp. 3953-3958.
2. R. Taylor, X. Wang, and X. Xu, 1999, “Thermophysical Properties of Thermal Barrier Coatings,” Surface and Coating Technology, Vol. 120-121, pp. 89-95.
1. H. Dong, W. Fan, X. Wang, 1997, “Numerical Calculations of the Wind-induced Pressure Distribution on a Model Cabin,” Journal of the University of Science and Technology of China, April Issue, (in Chinese).

Conferences:

11. X. Wang, 2002, "Thermal and Thermomechanical Phenomena in Picosecond Laser Copper Interaction," to be presented at the 6th ASME/JSME Thermal Engineering Joint Conference, Hawaii.
10. X. Wang and X. Xu, 2002, "The Formation Process of Nanoparticles in Laser Materials Interaction," the 2002 ASME International Mechanical Engineering Congress and Exposition, New Orleans, LA.
9. X. Wang and X. Xu, 2002, "Nanoparticles Formed in Picosecond Laser Materials Interaction," the 8th AIAA/ASME Joint Conference on Thermophysics and Heat Transfer, St. Louis, MO.
8. X. Wang, X. Xu, "Molecular Dynamics Simulatin of Thermal and Thermomechanical Phenomena in Picosecond Laser Material Interaction," the 12th International Heat Transfer Conference, Grenoble, France, 2002.
7. X. Wang, X. Xu, “Molecular Dynamics Simulation of Heat Transfer and Phase Change during Laser Material Interaction,” Proceedings of the 35th National Heat Transfer Conference, ASME, 2001, paper# NHTC 2001-20070.
6. X. Wang and X. Xu, “Thermoelastic Wave in Pulsed Laser Micromachining,” 1st International Symposium on Laser Precision Micromachining, Omiya, Saitama, Japan, June 2000.
5. X. Wang and X. Xu, “Thermal and Thermomechanical Phenomena during Ultrafast Pulsed Laser Interaction with Tissues,” the 2000 ASME International Mechanical Engineering Congress and Exposition.
4. X. Wang and X. Xu, “Thermoelastic Wave Induced by Pulsed Laser Heating,” the 2000 ASME International Mechanical Engineering Congress and Exposition.
3. X. Wang, H. Hu, and X. Xu, “Photo-acoustic Measurement of Thermal Conductivity of Thin Films and Bulk Materials,” Proceedings of the 33rd National Heat Transfer Conference, Paper # NHTC99-183, 1999.
2. R. Taylor, X. Wang, and X. Xu, “Thermophysical Properties of Thermal Barrier Coatings,” the 1999 International Conference on Metallurgical Coatings and Thin Films, San Diego, CA.
1. X. Wang, G. Liao, Y. Zou and W. Fan, “Numerical Simulation of Bubble Driven Flow in Oil with Thermal Stratified Layer,” the 3rd Int. Sym. on Multi-Phase Flow and Heat Transfer, 1994, Xi’an, China.

Students

Cecil Lawrence (Ph.D.)
Zheng Li (Ph.D.)
Jun Xu (M.S.)
Zhanrong Zhong (Ph.D.)