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...     

Eco-friendly approach for preparation of hybrid silica aerogel via freeze drying method

Journal of Materials Science - In this paper, an eco-friendly method of producing hybrid silica aerogels by freeze-drying method (FD) is proposed. In the freeze-drying system, deionized water was...     

加工方式对玉筋鱼干风味的影响

为研究加工方式对玉筋鱼干风味的影响，实验按加工方式分为加盐煮制冷风干燥（boiling in salt solution followed by cold air drying，SCC）组和冷风干燥（cold air drying，CD）组。采用电子鼻技术、气相离子迁移谱（gas chromatography-ion mobility spectroscopy，GC-IMS）技术、氨基酸自动分析技术、高效液相色谱技术测定玉筋鱼干中的风味成分。结果表明，不同加工方式制作的玉筋鱼干在气味、滋味方面存在显著差异。电子鼻、GC-IMS技术均能区分不同工艺制作的玉筋鱼干气味，采用GC-IMS技术共分析出68 种挥发性成分，庚醛、戊醛、3-甲基丁醛对玉筋鱼干独特风味的形成有重要影响，其中3-甲基丁醛源自CD工艺，其区别于SCC工艺气味的关键物质。玉筋鱼干中的主要鲜味氨基酸是Glu，主要呈味核苷酸是肌苷酸；CD组玉筋鱼干中的鲜味氨基酸和甜味氨基酸含量占总游离氨基酸的比重高于SCC组，同时CD组滋味活性值、味精当量值均高于SCC组，所以仅采用CD工艺制作的玉筋鱼干滋味优于加盐煮制后CD工艺制作的玉筋鱼干。     

Function mechanism of Y2O3 additive in silicon powder nitridation

Effect of sole Y₂O₃ additive on the nitridation behavior of silicon powder was systematically studied using thermo gravimetry, differential thermal analysis, particle size analysis, X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscope and thermodynamic analysis in this paper. The thermo gravimetry results showed that Y₂O₃ additive can significantly decrease the initial nitriding temperature and increase the nitriding rate. This phenomenon can be attributed to the much lower reaction temperature of the silica film and Y₂O₃ additive than that of the silica film and silicon. In addition, Y₂O₃ additive has little effect on the nitridation of silicon powder at 1300°C. However, it can obviously enhance the nitridation of silicon powder and the formation of β-Si₃N₄ at 1400°C, which is evidenced by the fact that the overall conversion increases from 58.1% to 100% and the fraction of β-Si₃N₄ in generated Si₃N₄ increases from 7.9% to 68.2% with increasing the content of Y₂O₃ additive from 0 to 10 wt%.     

Influences of pre-forming on preparation of SiC by microwave heating

Silicon carbide (SiC) crystals were synthesized by microwave sintering using coal and tetraethoxysilane (TEOS) as raw materials. A sol-gel method was carried out to coat coal mineral particles with silicon dioxide (SiO₂). The mixed raw powders were pre-formed by uniaxial pressing into cylindrical pellets in dimension of ~ 30?×?3?mm². The pre-forming pressure was selected at 0?MPa, 1?MPa, 2?MPa, 3?MPa, 4?MPa and 5?MPa respectively, which led to different apparent density of the green pellets. The influence of apparent density of green pellets on microwave heating behavior was investigated. Different microwave thermal effects were analyzed. Techniques of XRD、SEM were carried out to characterize samples. It was found that pre-forming pressure showed crucial influences on microwave thermal effects and electric field (E-field) intensification. No SiC crystal could be formed without pre-forming pressure. Pre-forming pressure might be the prerequisite for synthesis of SiC by microwave heating. Five consecutive and indispensable heating stages including accumulation of residual air, microwave plasma generation, complex chemical reactions, nucleation and grain growth of SiC crystallites could be distinguished for samples under pre-forming pressure. Different pre-forming pressure leads to changes in heating behavior as well as morphologies of SiC crystals. ~ 4?MPa might be the optimized pre-forming pressure for both microwave plasma effects and E-field intensification.     

Healable,Recyclable, and Mechanically Tough Polyurethane Elastomers with Exceptional Damage Tolerance

There is a huge requirement of elastomers for use in tires, seals, and shock absorbers every year worldwide. In view of a sustainable society, the next generation of elastomers is expected to combine outstanding healing, recycling, and damage-tolerant capacities with high strength, elasticity, and toughness. However, it remains challenging to fabricate such elastomers because the mechanisms for the properties mentioned above are mutually exclusive. Herein, the fabrication of healable, recyclable, and mechanically tough polyurethane (PU) elastomers with outstanding damage tolerance by coordination of multiblock polymers of poly(dimethylsiloxane) (PDMS)/polycaprolactone (PCL) containing hydrogen and coordination bonding motifs with Zn²⁺ ions is reported. The organization of bipyridine groups coordinated with Zn²⁺ ions, carbamate groups cross-linked with hydrogen bonds, and crystallized PCL segments generates phase-separated dynamic hierarchical domains. Serving as rigid nanofillers capable of deformation and disintegration under an external force, the dynamic hierarchical domains can strengthen the elastomers and significantly enhance their toughness and fracture energy. As a result, the elastomers exhibit a tensile strength of ≈52.4 MPa, a toughness of ≈363.8 MJ m⁻³, and an exceptional fracture energy of ≈192.9 kJ m⁻². Furthermore, the elastomers can be conveniently healed and recycled to regain their original mechanical properties and integrity under heating.     

烧结混合机细颗粒物蒸汽相变凝并及水浴协同治理

分析了蒸汽相变凝并及水浴协同治理技术。A钢铁厂烧结一次混合机采用该技术改造后,工作环境明显改善,车间环境空气颗粒物质量浓度大幅降低,设备各项运行参数良好,排放质量浓度满足钢铁企业超低排放指标限值要求。