Composition Dependence of Electronic, Elastic, and Polarization Properties of Wurtzite InxGa1-xN and CdxZn1-xO Ternary Alloys

We report the results of density functional theory calculations of several properties of wurtzite-structured InGaN and CdZnO alloys. It is shown that the investigated properties, including the internal parameter, bandgap, mechanical moduli, and electric polarization are nonlinear functions of alloy composition, as they deviate from the linear behavior predicted by Vegard’s law. Based on these results, InGaN and CdZnO are materials whose properties can be tuned via In and Cd concentrations. The spontaneous and piezoelectric polarizations considerably affect the properties of alloys-based devices due to the huge electric fields that build up at the heteroineterfaces. In this work we propose a method of controlling such fields by employing the composition dependence of the total polarization. We support this proposal by showing that, in the case of InGaN, an optimal alloy composition can be found that effectively reduces the polarization-induced electric fields, thereby improving the efficiency of optoelectronic applications.

Optimizing polarization dehazing

In the process of haze removal by the polarization method, it is very important to obtain accurate polarization information. On the one hand, the influence of noise can be effectively suppressed by appropriately weighted amplifying the airlight degree of polarization and the airlight corresponding to an object at an infinite distance. On the other hand, the scattering energy in channels [Formula: see text] and [Formula: see text] is larger, so it can reflect the actual polarization information violently. Analysis indicates the appropriately weighted amplification for the airlight degree of polarization in these two channels that can improve their estimation accuracy to a certain extent, it makes the color of the restored images more natural, and the details of the images are also more abundant. Moreover, in some special scenes, the polarization of the direct transmission could not be ignored on account of its important contribution to the total polarization. Hence, when the polarization of the direct transmission needs to be involved, only the polarization of direct transmission that contributes significantly to the total polarization is considered, and the polarization of the direct transmission in other scenes is ignored. This can still effectively eliminate the color distortion of the special scenes in the recovery results, and can greatly reduce the time consumption.

Reciprocal Polarizable Embedding with a Transferable H2O Potential Function II: Application to (H2O)n Clusters & Liquid Water

The manuscript analyzes the accuracy of our recently developed reciprocal polarizable embedding scheme, where a density functional theory model of the QM region is coupled to a dipole- and quadrupole polarizable water potential of the MM region. We present calculations of water clusters and liquid water where we analyze the energy, atomic forces and total polarization to demonstrate that artifacts in energy and polarization introduced by the QM/MM coupling are small and well-behaved. Furthermore, our methodology improves the consistency of the structure of optimized water hexamer geometries when compared to results obtained with models that neglect polarization. Additionally, the manuscript provides evidence that our coupling scheme eliminates artifacts in the structure of liquid water obtained with simpler electrostatic embedding models.

Reciprocal Polarizable Embedding with a Transferable H2O Potential Function II: Application to (H2O)n Clusters & Liquid Water

The manuscript analyzes the accuracy of our recently developed reciprocal polarizable embedding scheme, where a density functional theory model of the QM region is coupled to a dipole- and quadrupole polarizable water potential of the MM region. We present calculations of water clusters and liquid water where we analyze the energy, atomic forces and total polarization to demonstrate that artifacts in energy and polarization introduced by the QM/MM coupling are small and well-behaved. Furthermore, our methodology improves the consistency of the structure of optimized water hexamer geometries when compared to results obtained with models that neglect polarization. Additionally, the manuscript provides evidence that our coupling scheme eliminates artifacts in the structure of liquid water obtained with simpler electrostatic embedding models.

Particle Production via Dirac Dipole Moments in the Magnetized and Nonmagnetized Exponentially Expanding Universe

In the present paper, we solve the Dirac equation in the 2+1 dimensional exponentially expanding magnetized by uniform magnetic field and nonmagnetized universes, separately. Asymptotic behaviors of the solutions are determined. Using these results we discuss the current of a Dirac particle to discuss the polarization densities and the magnetization density in the context of Gordon decomposition method. In this work we also calculate the total polarization and magnetization, to investigate how the magnetic field affects the particle production. Furthermore, the electric and the magnetic dipole moments are calculated, and based on these, we have discussed the effects of the dipole moments on the charge distribution of the universe and its conductivity for both the early and the future time epoch in the presence/absence of a constant magnetic field and exponentially expanding spacetime.

Survey of Demosaicking Methods for Polarization Filter Array Images

Snapshot polarization imaging has gained interest in the last few decades. Recent research and technology achievements defined the polarization Filter Array (PFA). It is dedicated to division-of-focal plane polarimeters, which permits to analyze the direction of light electric field oscillation. Its filters form a mosaicked pattern, in which each pixel only senses a fraction of the total polarization states, so the other missing polarization states have to be interpolated. As for Color or Spectral Filter Arrays (CFA or SFA), several dedicated demosaicking methods exist in the PFA literature. Such methods are mainly based on spatial correlation disregarding inter-channel correlation. We show that polarization channels are strongly correlated in images. We therefore propose to extend some demosaicking methods from CFA/SFA to PFA, and compare them with those that are PFA-oriented. Objective and subjective analysis show that the pseudo panchromatic image difference method provides the best results and can be used as benchmark for PFA demosaicking.

Coupled Mechanical and Electrochemical Analyses of Three-Dimensional Reconstructed LiFePO4 by Focused Ion Beam/Scanning Electron Microscopy in Lithium-Ion Batteries

Limited lifetime and performance degradation in lithium ion batteries in electrical vehicles and power tools is still a challenging obstacle which results from various interrelated processes, especially under specific conditions such as higher discharging rates (C-rates) and longer cycles. To elucidate these problems, it is very important to analyze electrochemical degradation from a mechanical stress point of view. Specifically, the goal of this study is to investigate diffusion-induced stresses and electrochemical degradation in three-dimensional (3D) reconstructed LiFePO4. We generate a reconstructed microstructure by using a stack of focused ion beam-scanning electron microscopy (FIB/SEM) images combined with an electrolyte domain. Our previous two-dimensional (2D) finite element model is further improved to a 3D multiphysics one, which incorporates both electrochemical and mechanical analyses. From our electrochemistry model, we observe 95.6% and 88.3% capacity fade at 1.2 C and 2 C, respectively. To investigate this electrochemical degradation, we present concentration distributions and von Mises stress distributions across the cathode with respect to the depth of discharge (DoD). Moreover, electrochemical degradation factors such as total polarization and over-potential are also investigated under different C-rates. Further, higher total polarization is observed at the end of discharging, as well as at the early stage of discharging. It is also confirmed that lithium intercalation at the electrode-electrolyte interface causes higher over-potential at specific DoDs. At the region near the separator, a higher concentration gradient and over-potential are observed. We note that higher over-potential occurs on the surface of electrode, and the resulting concentration gradient and mechanical stresses are observed in the same regions. Furthermore, mechanical stress variations under different C-rates are quantified during the discharging process. With these coupled mechanical and electrochemical analyses, the results of this study may be helpful for detecting particle crack initiation.

Comparative Study of the Characteristics in Strained AlxInyGa(1-x-y)N/InGaN and AlxInyGa(1-x-y)N/GaN Heterostructures

The paper emphasized on different characteristics AlInGaN/InGaN and AlInGaN/GaN heterostructures for enhancing the device performance. Effect of changing mole fraction in bandgap, strain, polarization have been investigated. Amount of sheet charge density created on the heterointerfaces of AlInGaN /InGaN and AlInGaN/GaN heterostructures have been calculated. It has been observed that with the increment of Indium mole fraction and the decrement of Aluminium mole fraction, the total polarization increases hence larger 2DEG and sheet charge density is created.

EIS Study and Role of Chloride Ions Concentration and Temperature on Passivity of AZ91D Mg Alloy

Mg alloy shows higher specific strength and ductility relative to aluminum and also lower machining and casting costs over to steels. However, it also shows limitation to use in many industrial applications due to the relatively poor corrosion resistance in many aqueous solutions.Corrosion and passivation study of magnesium alloy (AZ91D) in various Cl̄ions concentrations and temperatures were carried out using electrochemical impedance spectroscopy (EIS) in NaCl solutions of 0.4, 0.6, 0.8 & 1.0 molar (M) concentrations. The passivation behavior was also observed at temperature of 45°C, 55°C and 65 °C in 3.5 wt% NaCl solutions. The total polarization resistance was observed about 5530, 4030, 2465 and 2000 Ohms.cm2in solutions of 0.4, 0.6, 0.8 & 1.0 M NaCl respectively indicate reduction of film stability at higher chlorides concentration. A similar trend was found on increasing temperatures of 3.5 wt% NaCl solutions at 45°C, 55°C and 65 °C and noticed about 970, 600 and 300 Ohms.cm2respectively showed significant decline of passivity and more pitting tendency.