Adaptive synchronization of weighted complex dynamical networks through pinning

This paper considers the problem of controlling weighted complex dynamical networks by applying adaptive control to a fraction of network nodes. We investigate the local and global synchronization of the controlled dynamical network through the construction of a master stability function and a Lyapunov function. Analytical results show that a certain number of nodes can be controlled by using adaptive pinning to ensure the synchronization of the entire network. We present numerical simulations to verify the effectiveness of the proposed scheme. In comparison with feedback pinning, the proposed pinning control scheme is robust when tested by noise, different weighting and coupling structures, and time delays.     

Electron dynamics in modulation p-doped InGaAs/GaAs quantum dots

We investigate the electron dynamics of p-type modulation doped and undoped InGaAs/GaAs quantum dots using up-conversion photoluminescence at low temperature and room temperature. The rise time of the p-doped sample is significantly shorter than that of the undoped at low temperature. With increasing to room temperature the undoped sample exhibits a decreased rise time whilst that of the doped sample does not change. A relaxation mechanism of electron-hole scattering is proposed in which the doped quantum dots exhibit an enhanced and temperature independent relaxation due to excess built-in holes in the valence band of the quantum dots. In contrast, the rise time of the undoped quantum dots decreases significantly at room temperature due to the large availability of holes in the ground state of the valence band. Furthermore, modulation p-doping results in a shorter lifetime due to the presence of excess defects.     

Explicit and approximate theories of photothermal deformation in surface thermal lens technique

An explicit thermoelastic model is developed to describe the photothermal deformation of a coated sample excited by a cw modulated laser beam with a top-hat profile. The surface displacement obtained with this explicit model is compared to that obtained by an approximate model developed by Reichling and Gr?nbeck (J. Appl. Phys. 75, 1914 (1994)). Both thermoelastic models are then applied in a Fresnel diffraction based surface thermal lens (STL) theory. Numerical calculations are performed to investigate the differences between the explicit and approximate models in both surface displacement and STL signal. The simulation results show that the approximate model over-estimates the surface displacement and the corresponding STL signal amplitude. A decrease in the thermal diffusion length reduces the differences between the results obtained with the two thermoelastic models.     

Finite element modeling of laser-induced three-dimensional Transient Thermal Grating in two-layered systems

The three-dimensional (3D) temperature field of laser-induced transient thermal grating (TTG) for two-layered structures such as diamond/substrate is obtained by the finite element method (FEM). The numerical results indicate that the thickness of the diamond film has a significant influence on the temperature field. On the other hand, we further find that variation of the substrate significantly affects on the temperature distribution in the diamond film, which has been ascribed to the various thermal conductivities of the substrates.     

Test of pulse shape analysis using single Compton scattering events

Procedures developed to separate single- and multiple-site events in germanium detector are tested with specially selected event samples provided by an 18-fold segmented prototype germanium detector for phase II of the germanium detector array, GERDA. The single Compton scattering, i.e. single-site, events are tagged by coincidently detecting the scattered photon with a second detector positioned at a defined angle. A neural network is trained to separate such events from events which come from multi-site dominated samples. Identification efficiencies of ≈80% are achieved for both single- and multi-site events. PACS 23.40.-s; 14.60Pq; 29.40.-n     

Influence of reaction gas flows on the properties of SiGe:H thin film prepared by plasma assisted reactive thermal chemical vapour deposition

A new preparing technology, very high frequency plasma assisted reactive thermal chemical vapour deposition （VHFPA-RTCVD）, is introduced to prepare SiGe：H thin films on substrate kept at a lower temperature. In the previous work, reactive thermal chemical vapour deposition （I~TCVD） technology was successfully used to prepare SiGe：H thin films, but the temperature of the substrate needed to exceed 400℃. In this work, very high frequency plasma method is used to assist RTCVD technology in reducing the temperature of substrate by largely enhancing the temperature of reacting gases on the surface of the substrate. The growth rate, structural properties, surface morphology, photo- conductivity and dark-conductivity of SiGe：H thin films prepared by this new technology are investigated for films with different germanium concentrations, and the experimental results are discussed.     

Soliton squeezing generated in an all-fiber contiguration

We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.