1. Full name: Nguyen Cong Toan                                     2. Sex: Male

3. Date of birth: 03/09/1981                                              4. Place of birth: Bac Giang

5. Admission decision number:  No. 4982/QĐ-ĐHKHTN signed 27/11/2013 by the Rector of VNU University of Science.

6. Changes in academic process: Non

7. Official thesis title: The thermodynamic parameters in XAFS of the doped material and the thermodynamic theory of melting point temperature.

8. Major:           Theoretical physics and mathematics physics    9. Code: 62440103

10. Supervisors:            Prof. Dr. Nguyen Van Hung.

11. Summary of the new findings of the thesis:

Extended the Anharmonic Correlation Einstein Model for doped materials. Based on quantum mechanics and quantum statistics, constructed analytical expressions for cumulants in XAFS, Morse potential and effective anharmonic atomic interaction potential of materials containing dopant atoms. Thermodynamic properties such as mean latic displacemence, mean square relative displacemence, or anharmonic effects of doped materials are also constructed. This could be extended to the study of compounds, alloys or defect materials.

Developed a lattice thermodynamic theory of melting curves or melting phase diagram of two-component alloys, thereby determining Lindemann melting temperature and Eutectic point of two-component alloys. The advantage of this theory is that instead of calculating the melting temperature of each alloy with a certain percentage one can obtain the melting temperature of the alloy with any proportion of the constituents.

The dependence of melting temperatures and atomic binding energies on the proportion of elements constituting two-component alloys has been evaluated, which suggests that the material becomes easier or harder to melt when blended to become alloy. This may be useful for material use.

Numerical calculation result for some specific examples by using current theory shows a good agreement in compared with experiment as well as other theories.

12. Paratical applicability, if any: The results of the thesis contribute to a richer and more detailed picture of the materials and may contribute to the material using technology in the future.

13. Further research directions, if any: Develop a theory that more fully describe the character of the material and develop additional methods for the material technology.

14. Thesis-related publications:

- The new findings of the thesis are published in the nine articles, in national scientific journals (6 papers) and international (3 papers).

- Nguyen Cong Toan, Nguyen Van Hung (2004), “Study of Morse Potential, Binding Energy, Thermal Expansion and Their Relations”, VNU-Jour. Science 20(3AP), p. 136.

- Nguyen Van Hung, Nguyen Cong Toan, Tran Trung Dung (2004), “Study of Interaction Potential and Force Constants of fcc Crystals Containing n Impurity atoms“, VNU-Jour. Science 20(2), pp. 9-19.

- Nguyen Van Hung, Ho Khac Hieu, Nguyen Cong Toan (2006), “Thermodynamic and Correlation Effects in Atomic Vibration of bcc Crystals Containing Dopant Atom”, VNU- Jour. Science 12(1), pp. 26-32.

- Nguyen Van Hung, Tran Trung Dung, Nguyen Cong Toan (2006), “Study of EXAFS cumulants of fcc crystals containing n dopant atoms”, VNU-Jour. Science 22(3), pp. 31-38.

- Nguyen Van Hung, Le Thi Hong Lien, Nguyen Cong Toan (2008), “High-order Anharmonic Effective Potentials and EXAFS Cumulants of fcc Crystals Containing Doping Atom”, VNU-Jour. Science 24, pp. 13-17.

- Nguyen Van Hung, Nguyen Cong Toan, Hoang Thi Khanh Giang (2010), “Calculation of Lindemann’s melting temperature and eutectic point of bcc binary alloys”, VNU-Jour. Science 26, p. 147.

- Nguyen Van Hung, Dung T. Tran, Nguyen Cong Toan, and Barbara Kirchner (2011), “A thermodynamic lattice theory on melting curve and eutectic points of binary alloys. Application to fcc and bcc structure”, Cent. Eur. J. Phys. 9(1), pp. 222-229.

- Nguyen Van Hung, Nguyen Cong Toan, Nguyen Ba Duc, Dinh Quoc Vuong (2015), “Thermodynamic properties of semiconductor compounds studied based on Debye-Waller factors”, Cent. Eur. J. Phys. (Open Physics) 13, p. 242.

- Nguyen Cong Toan, Nguyen Van Hung, Nguyen Ba Duc, Dinh Quoc Vuong (2016), “Theoretical study of phase diagram, Lindemann melting temperature and Eutectic point of binary alloys”, Int. J. Adv. Mater. Research 2(5), pp. 80-85.