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Using first-principles calculations based on density functional theory, we investigated systematically the electronic structures and magnetic properties of Ti-doped ZnO. The results indicate that Ti doped ZnO prefers the ferromagnetic ground state and shows a metallic behavior. We found that Ti-doped ZnO is a weak ferromagnet and FM exchange interaction is short-ranged. In addition, it has been found that Ti atoms have a tendency of cluster together around O atoms.

The geometrical structure of Y3Al5O12 (YAG) crystal was optimized by using first-principles calculation scheme, i.e. generalized gradient approximation (GGA) with the PW91 exchange correlation potential and “on the fly” pseudo-potential (OTFPP). The obtained lattice parameters are in good accordance with experimental results reported in the literature. This confirms the validity of the present GGA-OTFPP scheme. The total energy, populations, and contour maps of total charge density of YAG system were calculated with the same scheme. The derived formation energy (-2.396eV) indicate the good stability of the structure. The obtained Mulliken charge populations of atoms, overlap populations, as well as contour maps of total charge density congruously show that YAG crystal is a mixed bond material with stronger ion bond and weaker covalence bond.

The equilibrium structures of orthorhombic LaCrO3(O-LaCrO3) and rhombohedral LaCrO3(R-LaCrO3) crystals were investigated by using the plane-wave self consistent field (PWSCF) method based on density functional theory (DFT). The optimized lattice parameters for both phases are in accordance with experimental results reported in literature, confirming the reliability of LSDA+U scheme used in the calculations. We have quantificationally investigated the binding energies and electronic properties of these two types of LaCrO3crystals. The negative total energy and binding energies indicate the ground state property and the good structrual stability of O-LaCrO3crystal, which is important for the preparation of nano materials, the synthesis of ceramic materials made of doped O-LaCrO3crytals, as well as their applications in high technology fields, and predict the metastable property of R-LaCrO3crystal. Furthermore, the band structures show that O-LaCrO3is a direct semiconductor with wide energy gap, while R-LaCrO3is an indirect semiconductor with narrow energy gap. The interaction between Cr and O atoms in O-LaCrO3crystal possesses the character of covalent bonding.

The structures and electronic properties of (LaxAl1-x)2O3 are studied by first-principles calculation method. The results show that the composite material (LaxAl1-x)2O3 tend to be in sixfold-coordinated structure when x0.7. (LaxAl1-x)2O3 is in disorder structure and get the minimum band gap when x equals about 0.7. It suggest that (LaxAl1-x)2O3 can be synthesized as high dielectric constant material by doping La2O3 with a lower Al dopant concentrations or by fabricating (LaxAl1-x)2O3 with rich Al content.

The stability and electronic structures of Al or/and P doped single-walled SiC nanotubes (SWSiCNTs) are investigated by the first-principles theory. It is found that the ones with P atom located at Si site are most energetically favorable both for armchair and zigzag SWSiCNTs, which means that P atom is prone to substitute Si atom. In the same time, we found that the formation energy of Al substituting Si atom is lower than that of Al substituting C atom. The energetic disadvantages of P or Al atom located at C site in SWSiCNTs may be due to the obviously structural distortion in view of that the Al and P atoms are much bigger than C atom. The SWSiCNTs can be routinely modified ranging fromp-type semiconductor ton-type by Al and P substitution doping. These results are expected to give valuable information in building nanoscale electronic devices.

The geometry optimization, formation energy, Mulliken populations, and density of states of YAP (YAlO3) crystal are studied by using first-principles method based on density functional theory. The optimal lattice parameters of YAP crystal are in good accordance with experimental results reported. The calculated formation energy (-3.73eV) indicates the excellent structural stability of YAP crystal. The obtained Mulliken charge populations of O, Al and Y atoms and their deviations from the formal ones, as well as overlap populations show YAP crystal is a mixed bond material with stronger ionic and weaker covalent bonds, which is attributed to the hybridization of atomic orbitals. The comprehensive effect of various interactions in the system makes YAP crystal more stable.

In the development of software project, requirements stability is an important factor which relates to success or failure of software project. This paper made a detailed analysis of the factors of affecting the requirements stability, proposed the control method of the requirements change, and has conducted the research on the measure of the requirements stability for achieving the purpose to grasp the degree of the requirements change effectively, minimize the defects and risks caused by it, and ensure the successful completion of software project according to a predetermined cost, schedule, and quality.

We investigated the colossal dielectric constant behavior and interesting dielectric relaxation over broad temperature and frequency ranges in complex perovskite Sr0.9Ba0.1Ti0.9Ru0.1O3 ceramics by using HP4294 impedance analyzer. Through the discussion, there exists a clear link between the dielectric relaxation and the sample conductivity. It’s believed that hopping of electrons between color centers not only produce conductivity but also give rise to dielectric relaxation behavior.

Research information is an important work in research management of college, and involves abundant information in content and range. This article describes the overall design framework, design ideas as well as function modules of a Research Management Information System. The system not only greatly reduce the workload and improve efficiency of research management, but also would provide a large number of detailed historical data in management decisions.