Frequency Selectivity Behaviour in the Auditory Midbrain： Implications of Model Study

By numerical simulations on frequency dependence of the spiking threshold, i.e. on the critical amplitude of periodic stimulus, for a neuron to fire, we find that bushy cells in the cochlear nuclear exhibit frequency selec- tivity behaviour. However, the selective frequency band of a bushy cell is far away from that of the preferred spectral range in human and mammal auditory perception. The mechanism underlying this neural activity is also discussed. Further studies show that the ion channel densities have little impact on the selective frequency band of bushy cells. These findings suggest that the neuronal behaviour of frequency selectivity in bushy cells at both the single cell and population levels may be not functionally relevant to frequency discrimination. Our results may reveal a neural hint to the reconsideration on the busily cell functional role in auditory information processing of sound frequency.     

Giant magnetoresistance in Co–Al2O3 granular films prepared by self-organized growth

Co–Al₂O₃ granular films with a narrow distribution in cluster size of Co clusters embedded in Al₂O₃ matrix were prepared by sequential deposition based on self-organized growth. Resistivity dependence of giant magnetoresistance (GMR) was studied. The GMR takes a maximum of 5.2% at room temperature and 9.4% at 13 K and 5700 Gs when the resistivity of the sample is 4×10⁵–7×10⁵ μΩ cm. The temperature dependence of resistivities and GMR were discussed especially. A temperature dependence of conductance ρ∼exp[T₁/(T+T₀)] was found, which indicates the dominant conduction mechanism is fluctuation-induced tunneling. A linear relationship of GMR versus T was observed, GMR=a–kT, in applied magnetic field 5700 Gs. The remarkable character of temperature dependence of GMR should be due to the special microstructure that the clusters are monodispersed in the films.     

Husimi Operator for Describing Probability Distribution of Electron States in Uniform Magnetic Field Studied by Virtue of Entangled State Representation

For the first time we introduce an operator Δ _h (γ,ε;κ) for studying Husimi distribution function in phase space (γ,ε) for electron’s states in uniform magnetic field, where κ is the Gaussian spatial width parameter. The marginal distributions of the Husimi function are Gaussian-broadened version of the Wigner marginal distributions. Using the Wigner operator in the entangled state 〈λ | representation we find that Δ _h (γ,ε;κ) is just a pure squeezed coherent state density operator | γ,ε〉 _{κ κ} 〈γ,ε |, which brings much convenience for studying Husimi distribution, so we name Δ _h (γ,ε;κ) the Husimi operator. We then derive Husimi operator’s normally ordered form that provides us with an operator version to examine various properties of the Husimi distribution. Work supported by the National Natural Science Foundation under the grant: 10775097.     

Application of Cosine Zone Plates to Image Encryption

We analyse the diffraction result of optical field after Cosine zone plate, and theoretically deduce its transform matrix. Under some conditions, its diffraction distribution is a mixture of fractional Fourier spectra. Then we use Cosine zone plate and its diffraction result to image encryption. Possible optical image encryption and decryption implementations are proposed, and some numerical simulation results are also provided.     

Vertically aligned γ-AlOOH nanosheets on Al foils as flexible and reusable substrates for NH<Subscript>3</Subscript> adsorption

Vertically aligned γ-AlOOH nanosheets (NSs) have been successfully fabricated on flexible Al foils via a solvothermal route without morphology-directing agents. Three different reaction temperature (25, 80, and 120 ?C) and time (30 min, 45 min, and 24 h) are discussed for the growth period, which efficiently tune the density and size of the γ-AlOOH NSs. Meanwhile, the growth speed of the nanosheets confirms that dominant growth stage is seen in the initial 45 min. Furthermore, the interlayer of the γ-AlOOH NSs displays an average height of 140 nm and superhydrophilicity. By dynamic adsorption, the assynthesized γ-AlOOH NSs exhibit an outstanding NH₃ adsorption capacity of up to 146 mg/g and stably excellent regeneration for 5 cycles. The mechanism of NH₃ adsorption on the in-plane of the γ-AlOOH NSs is explained by the Lewis acid/base theory. The H-bond interactions among the NH₃ molecules and the edge groups (-OH) further improve the capture ability of the nanosheets.     

Dispirocycles: Platforms for the Construction of High-Performance Host Materials for Phosphorescent Organic Light-Emitting Diodes

Spirocyclic compounds such as 9,9′-spirobifluorene (SBF) are becoming more and more attractive for use as host materials in organic optoelectronic devices. Herein, two dispirocycles, namely, dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine], were used for the construction of host materials 1 – 4 . The attached triphenylamino group determines the thermal, photophysical, electrochemical, and charge-transport properties, and therefore they have different electroluminescent performances. The device based on dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] ( 2 ) and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine] ( 3 ) molecular platforms exhibited external quantum efficiencies of greater than 21 % with a very high power efficiency (≈100 lm W⁻¹). These results demonstrate the potential of extending the application of dispirocyclic molecular platforms with inherent rigidity for developing highly efficient host materials for organic light-emitting diodes.     

Progress of organic magnetic materials

Over the past years, the development of magnetic materials has been intensively explored, both for fundamental research and technological applications. Particularly, several materials with large magnetoresistance effect have received significant interest.In this study, we provide an analysis of the progress of organic magnetic materials and organic magnetoelectric complexes, thus paving the way for the understanding of organic magnetism and magnetoelectric coupling mechanisms. In addition, this analysis provides us a critical guide for future organic magnetic material design and fabrication.     

Near-infrared absorption enhancement for perovskite solar cells via the rear grating design

Optical and Quantum Electronics - The features of laser shock peening technology was studied in relation to the physical processes occurring during and after laser treatment. The effect of laser...