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The formation energy, the geometric structure, the electronic structure and the optical properties of pure and Si-doped orthorhombic SrHfO 3 with Si substituting Hf were studied by the first-principles method using plane-wave ultra-soft pseudo-potential calculation based on density functional theory. The negative formation energy results show the reactions from single elements to Si-doped SrHfO 3 are energetically favorable and that Si prefers entering the Hf sites rather than the Sr sites. The calculated equilibrium lattice constants of pure SrHfO 3 are in good agreement with previous experimental and theoretical results, and the substitution of Si for Hf results in a decrease in the lattice constants. The band structure indicates the band gap decreases after introduction of Si to Hf site. The Mulliken analysis and charge densities suggest that the Hf-O bond is mainly covalent, and the Sr-O bond is mainly ionic in Si-doped SrHfO 3 . The dielectric functions, the reflectivity, the absorption coefficient, the refractive index, and the energy-loss spectrum were also calculated to get a better understanding of optical properties of Si-doped SrHfO 3 .

Structural, elastic and electronic properties of tetragonal HfO2 at applied hydrostatic pressure up to 50 GPa have been investigated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated ground-state properties are in good agreement with previous theoretical and experimental data. Six independent elastic constants of tetragonal HfO2 have been calculated at zero pressure and high pressure. From the obtained elastic constants, the bulk, shear and Young's modulus, Poisson's coefficients, acoustic velocity and Debye temperature have been calculated at the applied pressure. Band structure shows that tetragonal HfO2 is an indirect band gap. The variation of the gap versus pressure is well fitted to a quadratic function.

Mg2Ge with anti-fluorite structure at ambient pressure is characterized as a narrow band semiconductor and increasing pressure results in a decrease of the gap. In this work, the band structure of anti-fluorite Mg2Ge under high pressure is studied by first principles calculations, which suggests that Mg2Ge becomes metallic at 7.5 GPa as a result of band gap closure. The enthalpy difference between anti-fluorite phase and anti-cotunnite phase under high pressure is calculated by the first-principles plane-wave method within the pseudopotential and generalized gradient approximation. The results show that Mg2Ge undergoes a phase transition from the anti-fluorite structure to anti-cotunnite structure at 11.0 GPa. Then we investigate experimentally the pressure-induced metallization of Mg2Ge by electric resistance measurement in strip anvil cell and Raman spectroscopy by diamond anvil cell. The pressure distribution is homogeneous along the central line of the strip anvil and the pressure is changed ccontinuously by using a hydraulically driven two-anvil press. Raman scattering experiment is performed at pressure up to 21.1 GPa on a back scattered Raman spectrometer. The wavelength of excitation laser is 532 nm. No pressure-transmitting is used and pressure is determined by the shift of the ruby luminescence line. It is found that neither a discontinuous change of electrical resistance at 8.7 GPa nor Raman vibration modes of Mg2Ge appear above 9.8 GPa. The disappearance of the Raman vibration mode is ascribed to the metallization since the the free carrier concentration rises after metallization has prevented the laser light from penetrating into the sample. We compare these results with those of resistivity measurements in diamond anvil cell. Li et al.[2015 Appl. Phys. Lett. 107 142103] reported that Mg2Ge becomes metallic phase at 7.4 GPa and is transformed into metallic anti-cotunnite phase at around 9.5 GPa. We speculate that the discontinuous change in electric resistance at 8.7 GPa is ascribed to the gap closure of anti-fluorite phase and Mg2Ge may transform into the anti-cotunnite phase above 9.8 GPa.

One of the important problems in system biology is to discover the relationship between topological properties and functional features of proteins in protein-protein interaction (PPI) networks. There are many essential-nonhub proteins and lots of nonessential-nonhub proteins in the PPI network. Both essential-nonhub proteins and nonessential-nonhub proteins are low-connectivity proteins, but they have different lethality. In order to explain why nonessential-nonhub proteins are not essential, we compare them with essential-nonhub proteins from topological view. The comparison results show that there are statistical differences between nonessential-nonhub proteins and essential-nonhub proteins in centrality measures and clustering coefficient.

Centrality-lethality rule demonstrates that proteins with high degree in the protein-protein interaction (PPI) network are more likely to be essential than those selected by chance. Nevertheless, in PPI network, there are still many proteins with high degree are not essential (false hubs). Comparing the difference between false hubs and essential hubs from topological perspective, such as centrality measures, damage, clustering coefficient and interactions between neighbors, there are distinguishable significant properties of false hubs. False hubs have lower sub graph centrality and less interactions between neighbors, which could explain why they are not essential in some extent.

Signal demodulation is a key technique for the fiber grating sensor. A new fiber Bragg grating dynamic signal demodulation method based on work-point controlling is present in the paper. The operation principle of the new method and the signal processing scheme of the work-point controlling are expounded systematically. The experiment measurement device is built using the tunable narrow-band laser, which has achieved signal demodulation with high precision. The influence of temperature drift on the measurement results is eliminated with work-point controlling scheme and the ability of dynamic signal detection capability of the fiber grating is greatly improved.

The reason for centrality-lethality is still an intriguing question. The idea of party and date hub proteins has been influential in the study of protein-protein interaction networks. But the validity of the party/date hub distinction has been debated. Using average Pearson correlation coefficient in cell cycle, stress response and DNA damage, we confirmed the distinction of E-party hub and E-date hub proteins. The results also support the classification of hub proteins into party hub and date hub proteins.

In the analysis of Protein-Protein Interaction (PPI) network, one intriguing problem is the reason for centrality-lethality rule. To discover the relationship between topological properties and functional features of proteins in PPI network, we classified hub proteins into two types: essential hub and nonessential hub and combined proteins' topological structure and evolutionary rate information together. We found that essential hub proteins tend to be intra-modular hubs and they had higher evolutionary conservation, nonessential hub proteins tend to be inter-modular hubs and they had lower evolutionary conservation.

The centrality-lethality rule reveals that topological prominence of a protein indicates its functional importance. But are all hub proteins in PPI network essential? Using P-value to weight PPI networks, we classified hub proteins into two types: essential hub and nonessential hub. The weighted centrality measure of weighted PPI networks showed that the weighted method can give greater support for functional characterization of hub proteins. We found that essential hubs are vital and they tend to be intra-modular hubs, while nonessential hubs are useful in maintaining the overall network connectivity and tend to be inter-modular hubs.

Shipping-radiated noise include mechanism noise, propeller noise and water-power noise. Propeller cavitation noise is the main noise when cavitation happens. While the shipping cavitation developed, the fall measure of per times frequency minished gradually in high frequency. In this paper, analyse the condition of cavitation, and establish propeller cavitation spectrum model, finally interpretation the above phenomenon according to simulation the model at different conditions and find that vacuole average radius's difference make the amplitude increased different at high frequency section.

One of the most important problems in biology is to discover the relationship between topological properties and functional features of proteins in Protein-Protein Interaction (PPI) network. The centrality-lethality rule reveals that hub proteins tend to be more essential than non-hub proteins. Why hub proteins tend to be more essential? Here, we classified hub proteins into two types: essential hub and nonessential hub. We found that essential hubs are more important to the survival of the cell and they can be called intra-modular hubs while nonessential hubs tend to be inter-modular hubs.

First-principles calculations of structural, electronic, optical, elastic, mechanical properties, and Born effective charges of monoclinic HfO2 are performed with the plane-wave pseudopotential technique based on the density-functional theory. The calculated structural properties are consistent with the previous theoretical and experimental results. The electronic structure reveals that monoclinic HfO2 has an indirect band gap. The analyses of density of states and Mulliken charges show mainly covalent nature in Hf-O bonds. Optical properties, including the dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function, and optical conductivity each as a function of photon energy are calculated and show an optical anisotropy. Moreover, the independent elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, compressibility, Lame constant, sound velocity, Debye temperature, and Born effective charges of monoclinic HfO2 are obtained, which may help to understand monoclinic HfO2 for future work.