Annealing and doping-dependent magnetoresistance in single layer poly(3-hexyl-thiophene) organic semiconductor device

We compare the current density–voltage (J–V) and magnetoconductance (MC) response of a poly(3-hexyl-thiophene) (P3HT) device (Au/P3HT(350 nm)/Al) before and after annealing above the glass transition temperature of 150 °C under vacuum. There is a decrease of more than 3 orders of magnitude in current density due to an increase of the charge injection barriers after de-doping through annealing. An increase, approaching 1 order of magnitude, in the negative MC response after annealing can be explained by a shift in the Fermi level due to de-doping, according to the bipolaron mechanism. We successfully tune the charge injection barrier through re-doping by photo-oxidation. This leads to the charge injection and transport transitioning from unipolar to ambipolar, as the bias increases, and we model the MC response using a combination of bipolaron and triplet-polaron interaction mechanisms.     

Solidification morphology and phase selection in drop-tube processed Ni–Fe–Si intermetallics

Drop-tube processing was used to rapidly solidify droplets of Ni_64.7Fe₁₀Si_25.3 and Ni_59.7Fe₁₅Si_25.3 alloys. In the larger droplets, and therefore at low cooling rates, only two phases, γ-Ni₃₁Si₁₂ and β₁-Ni₃Si were observed. Conversely, in the smaller droplets, and therefore at higher cooling rates, the metastable phase Ni₂₅Si₉ was also observed. The critical cooling rate for the formation of Ni₂₅Si₉ was estimated as 5 × 10³ K s⁻¹. SEM and TEM analysis reveals three typical microstructures: (I) a regular structure, comprising single-phase γ-Ni₃₁Si₁₂ and a eutectic structure between γ-Ni₃₁Si₁₂ and β₁-Ni₃Si; (II) a refined lamellar structure with a lamellar spacing <50 nm comprising γ-Ni₃₁Si₁₂ and β₁-Ni₃Si; (III) an anomalous structure with a matrix of Ni₂₅Si₉ and only a very small proportion of a second, and as yet unidentified, phase. These results indicate that there is an extended stability field for Ni₂₅Si₉ in the Ni-rich part of the Ni–Fe–Si ternary system in comparison to the Ni–Si binary system. With an increase of cooling rate, an increasing fraction of small droplets experience high undercoolings and, therefore, can be undercooled into the Ni₂₅Si₉ stability field forming droplets consisting of only the anomalous structure (III). The Fe atoms are found to occupy different substitutional sites in different phase, i.e. Fe substitutes for Ni in the γ phase and Si in the L1₂ (β₁) phase respectively.     

Simultaneous accommodation of Dy3+ at the lattice site of β-Ca3(PO4)2 and t-ZrO2 mixtures: Structural stability,mechanical, optical,and magnetic features

Structurally stable β-Ca₃(PO₄)₂/t-ZrO₂ composite mixtures with the aid of Dy³⁺ stabilizer were accomplished at 1500°C. The precursors comprising Ca²⁺, P⁵⁺, Zr⁴⁺, and Dy³⁺ have been varied to obtain five different combinations. The results revealed the fact that complete phase transformation of calcium-deficient apatite to β-Ca₃(PO₄)₂ occurred only at 1300°C, whereas the evidence of t-ZrO₂ crystallization is obvious at 900°C. The dual occupancy of Dy³⁺ at β-Ca₃(PO₄)₂ and t-ZrO₂ structures was evident; however, Dy³⁺ initially prefers to occupy β-Ca₃(PO₄)₂ lattice until its saturation limit and thereafter accommodates at the lattice site of ZrO₂. The typical absorption and emission behavior of Dy³⁺ were noticed in all the systems and, moreover, the surrounding symmetry of Dy³⁺ domains has been determined from the luminescence study. All the systems ensured paramagnetic response that is generally contributed by the presence of Dy³⁺. A gradual increment in the phase content of t-ZrO₂ in the composite mixtures ensured a significant improvement in the hardness and Young's modulus of the investigated compositions.     

Image Super-Resolution Based on Generative Adversarial Networks: A Brief Review

Single image super resolution (SISR) is an important research content in the field of computer vision and image processing. With the rapid development of deep neural networks, different image super-resolution models have emerged. Compared to some traditional SISR methods, deep learning-based methods can complete the superresolution tasks through a single image. In addition, compared with the SISR methods using traditional convolutional neural networks, SISR based on generative adversarial networks (GAN) has achieved the most advanced visual performance. In this review, we first explore the challenges faced by SISR and introduce some common datasets and evaluation metrics. Then, we review the improved network structures and loss functions of GAN-based perceptual SISR. Subsequently, the advantages and disadvantages of different networks are analyzed by multiple comparative experiments. Finally, we summarize the paper and look forward to the future development trends of GAN-based perceptual SISR.     

面向消费类电子产品的自动化生产线成组技术

针对现代消费类电子产品快速更新换代的现状, 介绍了该类产品的自动化生产线成组技术,阐述了通过度量消费类电子产品相似性和派生性特征,对产线进行成组编码的原理,研究产线工位单元的建模方法,描述了建模内容,并通过有无装载板的产线结构,论述了产线成组编码集成的途径和方法.     

Model Selection for Unsupervised Learning of Visual Context

This study addresses the problem of choosing the most suitable probabilistic model selection criterion for unsupervised learning of visual context of a dynamic scene using mixture models. A rectified Bayesian Information Criterion (BICr) and a Completed Likelihood Akaike’s Information Criterion (CL-AIC) are formulated to estimate the optimal model order (complexity) for a given visual scene. Both criteria are designed to overcome poor model selection by existing popular criteria when the data sample size varies from small to large and the true mixture distribution kernel functions differ from the assumed ones. Extensive experiments on learning visual context for dynamic scene modelling are carried out to demonstrate the effectiveness of BICr and CL-AIC, compared to that of existing popular model selection criteria including BIC, AIC and Integrated Completed Likelihood (ICL). Our study suggests that for learning visual context using a mixture model, BICr is the most appropriate criterion given sparse data, while CL-AIC should be chosen given moderate or large data sample sizes.     

垦71井区三维VSP资料波场分离方法应用研究

三维VSP资料是多偏移距VSP资料，资料中多种类型的波叠合在一起形成复杂波场。从复杂波场中分离出单一的保幅反射波波场是三维VSP波场分离的重要工作。常规二维VSP波场处理方法单一，难以适用于复杂的三维波场处理。针对三维VSP资料的波场特点，以分离上行反射P波为例，将单一波场分离方法加以适当组合，对垦71井区三维VSP实际资料进行了应用研究。结果表明，波场分离处理中叠加消去法和中值滤波相结合以及F—K滤波和中值滤波相结合的方法克服了单一方法的缺陷，波场处理后获得了波组特征明显、波场清晰单一的上行反射P波保幅波场，取得了较好的波场分离效果。