He Xingdao

Theoretical analysis of wavefront aberration from treatment decentration with oblique incidence after conventional laser refractive surgery.

Analysis of induced wavefront aberration after refractive surgery is important in the design of vision correction and the development of visual correction technology. Based on a mathematical model of the anterior corneal surface, the influence of treatment decentration on induced wavefront aberrations was studied by considering oblique incidence. The results revealed that significant coma was induced from the treatment translation, and it was nearly proportional to the translation or corrected refraction of vision correction. The induced aberrations from the lateral translation correlated with the angle formed by the position vector and the astigmatism axis of myopia astigmatism correction. The induced spherical aberration did not relate to a lateral translation of the center of the pupil, but was determined only by the corrected refraction. Additionally, no significant higher-order aberrations were induced from eye cyclotorsion for pure myopia or myopia astigmatism correction. Oblique incidence played an important role in the impact of treatment decentration on the induced aberrations in refractive surgery. The induced coma without considering the oblique incidence was obviously larger than that with it. In order to achieve the best postoperative visual performance, the effect of oblique incidence in refractive surgery should be taken into account, and treatment decentration should be minimized by all means, particularly for high myopia.

Collisions between Solitons Modulated by Gain/Loss and Phase in the Complex Ginzburg—Landau Equation

We present a systematic analysis for influence of phase on collisions of dissipative solitons, using the cubic-quintic complex Ginzburg?Landau equation in the absence of viscosity. Four generic outcomes are revealed upon the variation of gain/loss: merger of the two solitons into a single one; quasi-elastic interactions; creation of an extra soliton; and dissipation of the two solitons for in-phase. The velocities of the merger-soliton and the extra soliton can be effectively controlled by relative phase. The above features have potential applications in optical switching and logic gates based on interaction of optical solitons.

Analysis of Electron Recombination in Dye Sensitized Solar Cells Based on the Forward Bias Dependence of Dark Current and Electroluminescence Characterization

The current-voltage and electroluminescence characteristics of dye-sensitized solar cells (DSSCs) are investigated under forward dc bias in a dark environment at room temperature. The results show that the presence of dyes can play an important role in improving device performance, and also produce defects at the TiO2/dye/electrolyte interfaces, which dominate the electron-hole recombination process and become a limiting factor in obtaining high-efficiency DSSCs. The goodness of fit between measured and calculated data supports these conclusions.

Novel Dynamics of a Vortex in Three-Dimensional Dissipative Media with an Umbrella-Shaped Potential

We report the novel dynamic of 3D dissipative vortices supported by an umbrella-shaped potential (USP) in the 3D complex Ginzburg—Landau (CGL) equation with the cubic-quintic nonlinearity. The stable solution of vortices with intrinsic vorticity S=1 and 2 are obtained in the 3D CGL equation. An appropriate USP forces the vortices continuously to throw out fundamental 3D solitons (light bullets) along the folding umbrella. The dynamic regions of the strength of the potential with the changing number of folding umbrella are analyzed, and the rate of throwing increases with the strength of the potential. A weak potential cannot provide vortices with enough force. Then, the vortices will be stretched into polygons. However, a strong potential will destroy the vortices.

Far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under forward DC bias

The far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge solar cell are investigated under forward DC bias at room temperature in dark conditions. An electroluminescence viewgraph shows the clear device structures, and the electroluminescence intensity is shown to increases exponentially with bias voltage and linearly with bias current. The results can be interpreted using an equivalent circuit of a single ideal diode model for triple-junction solar cells. The good fit between the measured and calculated data proves the above conclusions. This work is of guiding significance for current solar cell testing and research.

Effect of Quantum Coins on Two-Particle Quantum Walks

We numerically study the effect of the quantum coins on the two-particle quantum walks on an infinite line. Both non-interacting and interacting particles are considered. The joint probability as well as the bunching or anti-bunching behavior are greatly affected by the phase factors in the coin operation. Further, the spatial correlation can be maximized by choosing appropriate coin parameters. The entanglement between the two particles can be adjusted in the same manner.

Spin Polarization Oscillation and Spin-Polarized Diode Based on Graphene Rashba–Strain Double Junctions

We investigate spin-dependent electron transport through graphene-based Rashba-strain double junctions. It is found that when electrons are injected from left normal graphene region, high spin polarization oscillation is achieved due to the wave-vector-dependent resonant tunneling. The spin polarization is negligible once the incident direction is reversed. Such a remarkable difference arises from pseudogap caused by the Rashba spin-orbit interaction.

A Fiber Optic Sensor for Real Time Monitoring of the Curing/cured State of Adhesives

Adhesives are widely used in the assembly of optoelectronic and/or electronic components. Based on the principle of Fresnel reflection, a fiber optic refract meter was set up to monitor the state of adhesives. The determined refractive indices of various liquids were consistent with their reference technical data. When taking a real time monitoring of adhesive refractivity on the refract meter, curing process of the adhesive and thermal expansion of the cured adhesive could be distinguished. Finally, the temperature dependence of the adhesive refractivity was verified with thermo-mechanical analysis through the Lorenz-Lorentz relation. Experimental results show that the setup can be a candidate replacement of thermal analysis apparatus.

Far-infrared electroluminescence characteristics of an Si-based photodiode under a forward DC bias current

At room temperature, the bias dependence of a far-infrared electroluminescence image of a photodiode is investigated in the dark condition. The results show that the electroluminescence image can be used to detect defects in the photodiode. Additionally, it is found that the electroluminescence intensity has a power law dependence on the dc bias current. The photodiode ideality factor could be obtained by a fitting a relationship between the electroluminescence intensity and the bias current. The device defect levels will be easily determined according to the infrared image and the extracted ideality factor value. This work is of guiding significance for current solar cell testing and research.