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A method to extract phase shifts and reconstruct the object wave in generalized phase-shifting interferometry (GPSI) is proposed. The phase distribution of a standard phase object and the least-square method are used to extract phase shifts over a wide range from 0 to π. Consequently, the tested object wave can be further reconstructed with the extracted phase shifts. It is accurate and applicable for GPSI of any frame number N (N ≥ 2). Computer simulation has verified its feasibility and validity. [ABSTRACT FROM AUTHOR]

We investigate high partial wave resonances in positron-hydrogen scattering using the momentum-space coupledchannels optical method above the H (n = 2) threshold. Resonances with angular momenta of L = 0-6 are reported. Ionization continuum and positronium formation channels are included via a complex equivalent local potential. Comparisons with the existing theoretical results are presented. [ABSTRACT FROM AUTHOR]

We provide alternatively a simple way of computing the Fresnel field integral, a further extension to the Gaussian-beam expansion. With a known result that the circ function is approximately decomposed into a sum of Gaussian functions, the zero-order Bessel function of the first kind is similarly expanded by the Bessel-Fourior transform. Two expansions are together inserted in this integral, which is then expressible in terms of the simple algebraic functions. The approach is useful in treatment of the field radiation problem for a large and important group of piston sources in acoustics. As examples, the calculation results for the uniform and the simply supported piston sources are presented, in a good agreement with those evaluated by numerical integration. [ABSTRACT FROM AUTHOR]

The five longest tune-out wavelengths for the rubidium atom are predicted from existing experimental and theoretical information by using an approximation formula. The formula is derived from the analysis of a non-relativistic configuration-interaction plus core polarization (CICP) calculation of the tune-out wavelengths for rubidium. The differences between the wavelengths predicted from the approximation formula and the exact CICP calculation are at the 10−3 nm level. The predicted five longest tune-out wavelengths are 790.115 nm, 423.155 nm, 421.111 nm, 359.429 nm, and 359.022 nm, respectively. [ABSTRACT FROM AUTHOR]

Despite the recent discovery of superconductivity in Nd1–xSrxNiO2 thin films, the absence of superconductivity and antiferromagnetism in their bulk materials remains a puzzle. Here we report the 1H NMR measurements on powdered Nd0.85Sr0.15NiO2 samples by taking advantage of the enriched proton concentration after hydrogen annealing. We find a large full width at half maximum of the spectrum, which keeps increasing with decreasing the temperature T and exhibits an upturn behavior at low temperatures. The spin-lattice relaxation rate is strongly enhanced when lowering the temperature, developing a broad peak at about 40 K, then decreases following a spin-wave-like behavior at lower temperatures. These results evidence a short-range glassy antiferromagnetic ordering of magnetic moments below 40 K and dominant antiferromagnetic fluctuations extending to much higher temperatures. Our findings reveal the strong electron correlations in bulk Nd0.85Sr0.15NiO2, and shed light on the mechanism of superconductivity observed in films of nickelates. [ABSTRACT FROM AUTHOR]

The negative refraction and imaging effects in photonic crystals can be used to solve diffraction limit problem in near-field optics. Improving transmission efficiency and image resolution is a critical work for negative refrac-tion imaging. We theoretically investigate the band structures, equi-frequency surfaces, electromagnetic wave propagation, and the image intensity distributions in a two-dimensional hexagonal photonic crystal consisting of hollow components. It is found that, in contrast to a hexagonal photonic crystal consisting of solid dielectric cylinders of the same radius, photonic crystals with hollow components can be used to optimize the all-angle negative refraction. Numerical simulations show that the transmission efficiency and resolution of image can be enhanced by changing the radii of the hollow air rods. [ABSTRACT FROM AUTHOR]

An external weak electric field is introduced into the small-world networks of Hodgkin-Huxley neurons to study the control and breakup of a spiral wave. The effect of an external electric field on the neurons in the smallworld network is described by an additive perturbation on the membrane potentials of neurons at the cellular level, in which an additive term VE is imposed on the physiological membrane potential. A statistical factor of synchronization is used to measure the collective behaviour of spiral waves by changing the electric field; it is confirmed that a smaller factor of synchronization is associated with the survival of a spiral wave. In the case of no channel noise, the spiral wave could be removed under a certain intensity of constant electric field; it keeps robustly to the weak electric field when the electric field changes periodically. In the case of weak channel noise, a breakup of the spiral wave is observed when the intensity of the electric field exceeds certain thresholds, which could be measured from the curve for synchronization factors. No drift of the spiral wave is observed under the weak electric field [ABSTRACT FROM AUTHOR]

We design and fabricate two types of superconducting niobium coplanar waveguide microwave resonators with different coupling capacitors on high purity Si substrates. Their microwave transmissions are measured at 20 mK. It is found that these two types of resonators possess significantly different loaded quality factors; one is 5.6 × 103 and the other is 4.0 × 104. The measured data are fitted well by classical ABCD matrix approach and consequently the coupling capacitances are determined. It is found that the transmission peak deviates from the standard Lorentizian with a frequency broadening. [ABSTRACT FROM AUTHOR]

The total ionizing dose radiation effects in the polycrystalline silicon thin film transistors are studied. Transfer characteristics, high-frequency capacitance-voltage curves and low-frequency noises (LFN) are measured before and after radiation. The experimental results show that threshold voltage and hole-field-effect mobility decrease, while sub-threshold swing and low-frequency noise increase with the increase of the total dose. The contributions of radiation induced interface states and oxide trapped charges to the shift of threshold voltage are also estimated. Furthermore, spatial distributions of oxide trapped charges before and after radiation are extracted based on the LFN measurements. [ABSTRACT FROM AUTHOR]

The low energy scattering of electrons by sodium at incident energies up to ionization threshold are calculated by applying the momentum space coupled-channel-optical (CCO) method. The present results are in good agreement with the previous experimental and theoretical results. Furthermore, three resonances in the total cross sections observed by previous experiments are proved by the present calculation. [ABSTRACT FROM AUTHOR]