A computational fluid dynamics numerical simulation was performed on Al₂O₃-synthetic oil nanofluids to study heat transfer in a trough solar receiver. Different nanofluid thermal conductivity models were tried. Calculated Nusselt numbers were compared with results of semiempirical model models. It was found that the thermal conductivity model based on Brownian motion predicted heat transfer characteristics well. The relative motion between nanoparticles and base fluid was found important in enhancing heat transfer. Further volume fraction analysis shows that the nanoparticles improved significantly average heat transfer coefficient, which indicates that nanofluids have great potential in solar collector applications.

Sodium sulfate is a common inorganic salt that causes blockage in supercritical water (SCW) reactors. An investigation of its crystallization kinetics is important for the design of deposition-preventing reactors. Microscopic crystallization process of sodium sulfate in SCW was studied with LAMMPS molecular dynamics simulation. Water molecule was calculated with SPC/E model, and ion-ion and ion-water interactions were calculated with Coulumb and Lennard-Jones combined potential energy functions. It shows that the impact of water on electrostatic shielding effect of ion charges decreases at higher temperatures and lower densities. Increasing temperature and density is advantageous to diffusion of ions, which helps ions to collide and form nuclei. Magnitude of nucleation rate is generally in the order of 10²⁹ cm^-3s^-1 in simulated parameters range of SCW.

Pseudopotential plane-wave method based on density functional theory was used to study influences of metal elements substitution on dehydrogenation of MgH₂. It shows that width of band gap and impurity energy levels are key factors. Impurity energy levels introduced by Fe, V, Nb, Ti are in the middle of energy gap, while those introduced by La are in the bottom of conduction band. Energy gap becomes narrower. The weakest Mg-H bond breaks easier, which is helpful to MgH₂ dehydrogenation. Covalent bonds formed between Nb, Fe, Ti, V, La and neighboring hydrogen lead to metal hydrides formation, which plays a catalytic role to dehydrogenation of MgH₂. Electrostatic forces between Mg₁ and surround hydrogens are no longer symmetrical duo to doping. H with weaker force to Mg releases easier, which improves dehydrogenation properties of MgH₂.

First-principles investigation on inelastic electron tunneling spectra of 1,6-hexanedithiol and 1,4-benzenedithiol molecular junctions with metal electrodes are performed.It shows that vibrational peaks in inelastic electron tunneling spectra are sensitive to electrode material and distance between sulfur atoms and electrodes.It hence provides unambiguous evidence that electrode material and metal-molecule bond length are crucial for inelastic electron transport through molecular junctions.The peak heights are mainly attributed to coupling energies between electrode and molecule.

The B3LYP method of density functional theory(DFT) is used to optimize geometry configuration,stability and frequency calculation of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) cation clusters at the level of 6-31G^*.Ground state of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) clusters are obtained.The geometry of clusters transforms from a planar structure to a spacial structure as cluster sizes of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) are increased to 6 and 7,respectively.Among Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) cation clusters,Ga₄N⁺,Ga₆N⁺,Ga₃N₂⁺ and Ga₅N₂⁺ are stabler.

Based on Ericksen-Leslie's elastic theory and dynamic theory, the responsive time parameter of the in-plane switching liquid crystal displays is analyzed, the chiral-planar alignment is introduced into this mode, and the dynamic equation of the director is given. The relation of the responding time and the twist angle is obtained by calculating the instantaneous distribution of the director in this mode. The computational result demonstrates that there is a short responding time in IPS-Chiral-Planar liquid crystal cell with a certain twist angle.

In the supertwisted nematic-liquid crystal display (STN-LCD), the director of liquid crystal is determined by the tilt angle θ and the twist angle φ. The ordinary differential equations and the boundary conditions satisfied by θ,φ and the electric potential U are obtained, based upon the continuum theory of liquid crystals. Solving two-point boundary problem of the ordinary differential equations by means of the relaxation method, dependence of the optical threshold voltage on the anchoring strength is calculated.

A 9_Bit square lattice gas model with temperature was introduced. We fulfilled an acoustic driver using Monte Carlo Method. Using this driver to generate plane waves, a standing sound wave was established in a two-dimensional pipe. This model can display the formation and change of the standing wave in real time and combined with its ability to simulate temperature variations, other phenomena, such as thermoacoustic, can be further analized on the microscopic level.