Fabrication of Cu(In,Ga)Se2 thin films by ion beam sputtering deposition from a quaternary target at different substrate temperatures

Cu(In, Ga)Se₂ (CIGS) thin films were fabricated by ion beam sputtering deposition from a single quaternary target at different substrate temperatures (T _sub). The thin films were characterized with X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and four-point probe technique to study the microstructures, surface morphology, composition and electrical properties, respectively. The results show that the films grown above 400?°C are of chalcopyrite structure. Cu(In_0.7Ga_0.3)Se₂ thin film was obtained when T _sub is 550?°C. The Cu and Se atomic percentage when T _sub is above 500?°C is higher than when T _sub is below 500?°C. With the increase in T _sub, the surfaces morphology of the films is denser and the resistivity of the films decreases.     

试样厚度对共聚聚烯烃材料断裂行为参数的影响

采用基本断裂功法对共聚聚丙烯压制双边缺口拉伸试样的断裂行为进行研究,分析了厚度变化对材料多项断裂参数的影响。结果表明,当厚度在0.6 mm~1.1 mm时,材料的断裂韧性we随厚度增大呈现出明显的下降趋势,下降幅度约30%,主要由屈服后的we,n降低所致,屈服前的we,y无明显变化;材料的比塑性功βwp随厚度增大未呈现明显的变化,且屈服前的βywp,y和屈服后的βnwp,n均无明显变化。同时求得了外推的零韧带断裂位移e0,b和最大载荷P0,y,随厚度增大,前者具有一定的下降趋势,后者则显示出较大的增长趋势。     

Analysis of the drude model in metallic films

A method, believed to be new, to simulate Drude parameters for collective oscillation of the free carriers in metallic films is proposed. Plasma resonance frequency and relaxation were simulated simultaneously from both the real and the imaginary parts of the dielectric function of a metallic film after consideration of their correlation in the Drude model. As examples, the contributions of the electrons in Ag films and of the free carriers in metallic silicide, NbSi(2) and TaSi(2), films have been studied.     

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

Fine‐tuning of the nanoscale morphologies of the active layers in polymer solar cells (PSCs) through various techniques plays a vital role in improving the photovoltaic performance. However, for emerging nonfullerene (NF) PSCs, the morphology optimization of the active‐layer films empirically follows the methods originally developed in fullerene‐based blends and lacks systematic studies. In this work, two solid additives with different volatilities, SA‐4 and SA‐7, are applied to investigate their influence on the morphologies and photovoltaic performances of NF‐PSCs. Although both solid additives effectively promote the molecular packing of the NF acceptors, due to the higher volatility of SA‐4, the devices processed with SA‐4 exhibit a power conversion efficiency of 13.5%, higher than that of the control devices, and the devices processed with SA‐7 exhibit poor performances. Through a series of detailed morphological analyses, it is found that the volatilization of SA‐4 after thermal annealing is beneficial for the self‐assembly packing of acceptors, while the residuals due to the incomplete volatilization of SA‐7 have a negative effect on the film morphology. The results delineate the feasibility of applying volatilizable solid additives and provide deeper insights into the working mechanism, establishing guidelines for further material design of solid additives.     

Study on the Ballistic Performance of Multiply Wadded Through-the-thickness Angle-interlock Fabric Reinforced Composites

Applied Composite Materials - The paper presents a study on the ballistic performance of 3D woven wadded through-the-thickness angle-interlock fabrics (TTAI) fabric reinforced composites. Their...     

Fluorescence recovery assay for the detection of protein-DNA binding

We report a novel and straightforward fluorescence recovery assay which enables the detection of protein-DNA interactions and simultaneously determines relative binding affinities of sequence-specific DNA-binding proteins for a variety of DNA sequences in a multiplexed format. The detection of protein-DNA binding is accomplished by monitoring fluorescence recovery during exonuclease digestion of DNA sequences that are modified with fluorophore-quencher pairs. Retardation of fluorescence recovery occurs with binding of the protein to the putative DNA binding element, which arrests exonuclease digestion. The assay detects protein-DNA binding in a homogeneous solution simply, quickly, and reliably without using radioisotopes. Multiplexing is possible by labeling different DNA sequences with spectrally distinct dyes, allowing simultaneous analysis of experimental and control binding reactions in the same mixture.     

Machine learning-based real-time visible fatigue crack growth detection

Many large-scale and complex structural components are applied in the aeronautics and automobile industries.However,the repeated alternating or cyclic loads in ...