Spherical shape BaO-ZnO-B<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript> glass powders prepared by spray pyrolysis

Fine-sized BaO-ZnO-B₂O₃-SiO₂ (BZBS) glass powders were directly prepared by high temperature spray pyrolysis. The hollow glass powders prepared at low preparation temperature of 1000 °C had a low density of 2.65 g/cm³. However, the densities of the BZBS powders obtained at preparation temperatures of 1200 and 1400 °C were each 3.92 and 4.13 g/cm³. The mean size of the BZBS glass powders prepared by spray pyrolysis at preparation temperature of 1400 °C was 0.98 μm. The glass transition temperature (T_g) of the prepared BZBS glass powders was 518.9 °C. The dielectric layers formed from the prepared BZBS glass powders with a dense structure had a clean surface and a dense inner structure without voids at the firing temperature of 580 °C. The transparencies of the dielectric layers formed from the prepared BZBS glass powders were higher than 90% within the visible range. PACS 42.70.Ce; 85.60.Pg; 71.55.Jv     

Direct observation of dispersive Kondo resonance peaks in a heavy-fermion system

Ce 4d-4f resonant angle-resolved photoemission spectroscopy was carried out to study the electronic structure of strongly correlated Ce 4f electrons in a quasi-two-dimensional nonmagnetic heavy-fermion system CeCoGe1.2Si0.8. For the first time, dispersive coherent peaks of an f state crossing the Fermi level, the so-called Kondo resonance, are directly observed together with the hybridized conduction band. Moreover, the experimental band dispersion is quantitatively in good agreement with a simple hybridization-band picture based on the periodic Anderson model. The obtained physical quantities, i.e., coherent temperature, Kondo temperature, and mass enhancement, are comparable to the results of thermodynamic measurements. These results manifest an itinerant nature of Ce 4f electrons in heavy-fermion systems and clarify their microscopic hybridization mechanism.     

Scale-invariant structure of energy fluctuations in real earthquakes

Earthquakes are obviously complex phenomena associated with complicated spatiotemporal correlations, and they are generally characterized by two power laws: the Gutenberg-Richter (GR) and the Omori-Utsu laws. However, an important challenge has been to explain two apparently contrasting features: the GR and Omori-Utsu laws are scale-invariant and unaffected by energy or time scales, whereas earthquakes occasionally exhibit a characteristic energy or time scale, such as with asperity events. In this paper, three high-quality datasets on earthquakes were used to calculate the earthquake energy fluctuations at various spatiotemporal scales, and the results reveal the correlations between seismic events regardless of their critical or characteristic features. The probability density functions (PDFs) of the fluctuations exhibit evidence of another scaling that behaves as a q-Gaussian rather than random process. The scaling behaviors are observed for scales spanning three orders of magnitude. Considering the spatial heterogeneities in a real earthquake fault, we propose an inhomogeneous Olami-Feder-Christensen (OFC) model to describe the statistical properties of real earthquakes. The numerical simulations show that the inhomogeneous OFC model shares the same statistical properties with real earthquakes.     

Negative and positive lateral shift of a light beam reflected from a grounded slab

We consider the lateral shift (LS) of a light beam reflecting from a dielectric slab backed by a metal. It is found that the LS of the reflected beam can be negative while the intensity of reflected beam is almost equal to the incident one under a certain condition. The explanation for the negativity of the LS is given in terms of the interference of the reflected waves from the two interfaces. It is also shown that the LS can be enhanced or suppressed under some other conditions. The numerical calculation on the LS for a realistic Gaussian-shaped beam confirms our theoretical prediction.     

Strain relaxation and surface morphology of high indium content InAlAs metamorphic buffers with reverse step

Low-temperature step-graded high indium content InAlAs (In% = 0.75) metamorphic buffer layers with reverse step layer grown on GaAs substrate by molecular beam epitaxy are investigated in this paper. The composition and the strain relaxation of the top InAlAs layer are determined by high-resolution triple-axis X-ray diffraction measurements, which show that the top InAlAs layer is nearly fully relaxed and the growth parameters for these samples have little influence on the strain relaxation ratio. Surface morphology is observed by reflection high-energy electron diffraction pattern and atomic force microscopy. The surface morphology is found to depend strongly on both the growth temperature and the As flux. Compared with other samples, the sample growth under the optimized conditions has the smallest value of root mean square surface roughness. Furthermore, the ω − 2θ and ω scans of the triple-axis X-ray diffraction and transmission electron microscopy result also show the sample grown under the optimized conditions has good crystalline quality.     

Photonic generation of microwave signals using dual-wavelength single-longitudinal-mode fiber lasers

Photonic generation of microwave signals is demonstrated with a dual-wavelength single-longitudinal-mode erbium-doped fiber ring laser. Microwave signal with a frequency of 21.07 GHz is obtained by aligning the reflection band of a uniform fiber Bragg grating to the two transmission peaks within a fiber Bragg grating-based Fabry-Perot filter. Stable dual-wavelength single-longitudinal-mode operation is guaranteed by means of the combined filtering effect of a saturable absorber and the Fabry-Perot filter. This approach provides an effective solution to the photonic generation of high-frequency microwave signals.     

New Exact Solutions for a Class of Nonlinear Coupled Differential Equations

More new exact solutions for a class of nonlinear coupled differential equations are obtained by using a direct and efficient hyperbola function transform method based on the idea of the extended homogeneous balance method.     

Evolution of a stress-driven pattern in thin bilayer films: spinodal wrinkling

We report the full spectrum of the evolution of the wrinkle pattern formation in a thin bilayer film of an elastic metal on a viscoelastic polymer. Although the origin is different, the transition of an initial islandlike pattern to a labyrinthine structure without any change in the wavelength (q approximately t(0)) and the overall evolutionary process is strikingly similar to that in the spinodal system but the process is robust and takes place on a long time scale (about 10 days). The change into a mountainous topography in the late stages is accompanied by an increase in the length scale from an initial wavelength to another. This change, due to the relaxation of the confined polymer that results in a transition from elastic- to viscouslike behavior, induces wave coarsening (q approximately t(-1.04+/-0.08)) and macroscopic roughening.     

THE REGULARITY OF SOLUTIONS FOR NONLINEAR DEGENERATE ELLIPTIC BOUNDARY VALUE PROBLEM

This paper is devoted lo the study of regularity of solutions for Dirichlet probelm ofnonlinear degenerate elliptic equations in two dimensional case. A sufficient condition fortheir solutions in C~(3+α)(Ω) to be certainly in C~∞(Ω) is given.