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Semi-analytical solution of optimization on moon-pool shaped WEC

Zhang W. C., Liu H. X., Zhang X. W., Zhang L.

Polish Maritime Research

2016

S 1

25--31

In order to effectively extract and maximize the energy from ocean waves, a new kind of oscillating-body WEC (wave energy converter) with moon pool has been put forward. The main emphasis in this paper is placed on inserting the damping into the equation of heaving motion applied for a complex wave energy converter and expressions for velocity potential added mass, damping coefficients associated with exciting forces were derived by using eigenfunction expansion matching method. By using surface-wave hydrodynamics, the exact theoretical conditions were solved to allow the maximum energy to be absorbed from regular waves. To optimize the ability of the wave energy conversion, oscillating system models under different radius-ratios are calculated and comparatively analyzed. Numerical calculations indicated that the capture width reaches the maximum in the vicinity of the natural frequency and the new kind of oscillating-body WEC has a positive ability of wave energy conversion.

Nanostructure model and optical properties of InAs/GaAs quantum dot in vertical cavity surface emitting lasers

Chen J., Fan W. J., Ding Y., Xu Q., Zhang X. W., Xu D. W., Yoon S. F., Zhang D. H.

Opto-Electronics Review

2011

Vol. 19, No. 4

449-453

We apply 8.band k.p model to study InAs/GaAs quantum dots (QDs). The strain was calculated using the valence force field (VFF) model which includes the four nearest.neighbour interactions. For the optical properties, we take into account both homogeneous and non.homogeneous broadening for the optical spectrum. Our simulation result is in good agreement with the experimental micro.photoluminescence (µm-PL) result which is from InAs/GaAs QD vertical cavity surface emitting lasers (VCSELs) structure wafer at room temperature. Accordingly, our simulation model is used to predict the QD emission from this QD.VCSELs structure wafer at different temperature ranging from 200–400 K. The simulation results show a decrease of 41 meV of QDground state (GS) transition energy from 250–350 K. The changes ofQDGS transition energy with different temperature indicate the possible detuning range for 1.3.µm wave band QD-VCSELs applications without temperature control. Furthermore, QD differential gain at 300 K is computed based on this model, which will be useful for predicting the intrinsic modulation characteristics of QD-VCSELs.