Design of aluminum trihydroxide and P‐N core‐shell structures and their synergistic effects on halogen‐free flame‐retardant polyethylene composites

In order to improve the performance of inorganic/organic composites, aluminum trihydroxide (ATH) core composites with a styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (MAH‐g‐SEBS) shell phase, and P‐N flame retardant as a synergistic agent, were prepared through an interface design. The effects of polyethylene glycol (PEG) content on the interfacial interaction, flame retardancy, thermal properties, and mechanical properties of high‐density polyethylene (HDPE)/ATH composites were investigated by small angle X‐ray diffraction, rotational rheometer, limiting oxygen index, thermogravimetric analysis (TGA), and tensile testing. The ATH synergistic effects of P‐N flame‐retardant improved the combustion performance of HDPE/ATH/PEG(3%)/MAH‐g‐SEBS/P‐N (abbreviated as HDPE/MH3/M‐g‐S/P‐N) composite by forming more carbon layer, increased the elongation at break from 21% to 558% compared to HDPE/ATH, and increased the interface thickness from 0.447 to 0.891 nm. SEM results support the compatibility of ATH with HDPE increased and the interfacial effect was enhanced. TGA showed the maximum decomposition temperature of the two stages and the yield of the residue at high temperature increased first and then decreased with the increase of PEG content. Rheological behavior showed the storage modulus, complex viscosity, and the relaxation time initially increased and then decreased with the increase of PEG content indicating PEG, M‐g‐S, and ATH powder gradually formed a partial coating, then a full coating, and finally an over‐coated core‐shell structured model.     

Capillary electrophoretic studies on quantum dots and histidine appended peptides self‐assembly

Herein, we designed four peptides appended with different numbers of histidine (His_n‐peptide). We launched a systematic investigation on quantum dots (QDs) and His_n‐peptide self‐assembly in solution using fluorescence coupled CE (CE‐FL). The results indicated that CE‐FL was a powerful method to probe how ligands interaction on the surface of nanoparticles. The self‐assembly of QDs and peptide was determined by the numbers of histidine. We also observed that longer polyhistidine tags (n ≤ 6) could improve the self‐assembly efficiency. Furthermore, the formation and separation of QD‐peptide assembly were also studied by CE‐FL inside a capillary. The total time for the mixing, self‐assembly, separation, and detection was less than 10 min. Our method greatly expands the application of CE‐FL in QDs‐based biolabeling and bioanalysis.     

Studies on multivalent interactions of quantum dots–protein self-assemble using fluorescence coupled capillary electrophoresis

A method is presented for using a single laser pulse to transform polymorphic polycrystalline gold nanoparticles (Au NPs) into crystalline nanospheres. Transmission electron microscope analysis of the nominally 60-nm-diameter Au NP starting material and the product suspension confirms the production of slightly smaller particles that exhibit greater crystallinity and feature reduced caliper diameter aspect ratios and anisotropy. Centrifugation followed by ultrasonic resuspension into citrate solution separates the nanospheres from the <15 nm ablation fragments, providing a route to monodisperse spherical crystalline Au NPs.     

In‐capillary detection of fast antibody‐peptide binding using fluorescence coupled capillary electrophoresis

Herein, we report a technique for detecting the fast binding of antibody‐peptide inside a capillary. Anti‐HA was mixed and interacted with FAM‐labeled HA tag (FAM‐E₄) inside the capillary. Fluorescence coupled capillary electrophoresis (CE‐FL) was employed to measure and record the binding process. The efficiency of the antibody‐peptide binding on in‐capillary assays was found to be affected by the molar ratio. Furthermore, the stability of anti‐HA‐FAM‐E₄ complex was investigated as well. The results indicated that E₄YPYDVPDYA (E₄) or TAMRA‐E₄YPYDVPDYA (TAMRA‐E₄) had the same binding priorities with anti‐HA. The addition of excess E₄ or TAMRA‐E₄ could lead to partial dissociation of the complex and take a two‐step mechanism including dissociation and association. This method can be applied to detect a wide range of biomolecular interactions.     

Effect of Tb content on microstructure and ferroelectric properties of Bi4−x Tb x Ti3O12 thin films grown by sol–gel method

The effects of Tb substitution on the structural and electrical properties of ferroelectric Bi₄Ti₃O₁₂ (BTO) thin films grown on Pt/TiO₂/SiO₂/Si substrates by a sol–gel process have been reported. X-ray diffraction indicated A-site Tb substitutions did not change the polycrystalline bi-layered Aurivillius structure of the BTO, but a lattice distortion was observed. The leakage current behavior at room temperature of the films was studied and it was found that the leakage current density decreased from 10^?2 to 10^?4 A/cm² with the increase of x under 150 kV/cm. The remnant polarization (2P _r ) and dielectric constant (ε _r) increase firstly and then decreases with the increase of the Tb content. We observed a substantial increase in the remnant polarization (2P _r ) with Tb substitution and obtained a maximum value of~60 μC/cm² at an applied electric field of 500 kV/cm for x = 0.4. Moreover, this BTT-0.4 capacitor did not show fatigue behaviors after 1.0 × 10¹⁰ switching cycles, suggesting an anti-fatigue character.     

用信息熵研究气象问题初探——湖北省气温信息熵分布规律的研究

介绍了用信息熵研究气象问题的初步作法及其效果。