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Seven layered C5N configurations constructed from hexagonal BN and graphite structures are studied using an ab initio pseudopotential density functional method. The structural and electronic properties, and pressure-induced phase transition are investigated by calculating the total energy, structural parameter, formation energy, elastic constant, band structure and electron density of state. The results show that the three C5N configurations constructed from the h-BN structure are more stable energetically than those four configurations from graphite structure. The C5N-I configuration with the highest symmetry and the AA stacking sequence along the c-axis is the most stable. This structure is stable mechanically and its phase separation is difficult. The C5N phase is expected to have a metallic character. A critical pressure of about 20GPa is predicted for the synthesis of a monoclinic C5N phase from the layered C5N phase. [ABSTRACT FROM AUTHOR]

An algorithm is proposed to enhance the resolution of digital holography by retrieving the frequency components lost in common holograms. A pinhole is placed directly behind the specimen to record the hologram, and an iterative scheme commonly used in coherent diffraction imaging is adopted for the reconstruction. Since some of the frequency components lost in common digital holography can be properly retrieved, the resolution of the reconstructed image is remarkably improved. Theoretical analysis and computer simulations are presented to demonstrate the feasibility of this proposed technique. [ABSTRACT FROM AUTHOR]

(Received 11 December 2012) The temperature, duration, activation energy, and Avrami exponent of the solid phase transformation β1→ α + α2 of TC4 titanium alloy treated at 3GPa in a cooling process are calculated by means of differential scanning calorimetric curves. Then the effects of high pressure on the β1→α + α2 phase transformation dynamics of TC4 alloy in a cooling process are investigated. The results show that 3GPa high pressure treatment can increase the activation energy of the TC4 alloy. The beginning time, end time, and duration of the β1→α + α2 phase transition of the 3GPa high pressure treated TC4 alloy at the cooling rate of 10°C/min are increased by 2.90°C, 7.78°C and -29.28 s respectively. It is known that 3GPa high pressure treatment has little effect on the phase transition mechanism. [ABSTRACT FROM AUTHOR]

We investigate metallic microdisk-size dependence of quantum dot (QD) spontaneous emission rate and micro-antenna directional emission effect for the hybrid metal-distributed Bragg reflector structures based on a particular single QD emission. It is found that the measured photoluminescence (PL) intensity is very sensitive to the size of metallic disk, showing an enhancement factor of 11 when the optimal disk diameter is 2 μm and the numerical aperture of microscope objective NA=0.5. It is found that for large metal disks, the Purcell effect is dominant for enhanced PL intensity, whereas for small size disks the main contribution comes from plasmon scattering at the disk edge within the light cone collected by the microscope objective. [ABSTRACT FROM AUTHOR]