果蔬自发气调包装中呼吸速率研究进展

气调包装可以有效延长果蔬保鲜期,减少果蔬储运过程中腐败变质造成的浪费。其中自发气调包装利用果蔬自身的呼吸作用和包装薄膜选择透过性,建立适宜果蔬保存的气体环境,降低果蔬的生理消耗,对延长保鲜期有明显功效。自发气调包装关键技术是果蔬呼吸速率和包装内外气体交换。本文综述了呼吸速率三种测量方法,分析了基于酶动力学和化学反应原理构建的果蔬呼吸速率模型,并基于阿伦尼乌斯方程和一元一次线性方程描述了模型参数对温度的依赖性,按照逻辑关系整合模型,总结出求解果蔬呼吸速率的路径以及选择适宜包装材料的方法。随着时代的发展自发气调包装技术将成为果蔬储运保鲜重要的应用方向,未来呼吸速率模型将更加细化,精准化,同时果蔬呼吸速率库的建立也更有利于自发气调包装的推广。     

A polyimide-based flexible monopole antenna

Journal of Materials Science: Materials in Electronics - A polyimide (PI)-based flexible monopole antenna fed by coplanar waveguide (CPW) was fabricated by self-assembly technology. The measured...     

An efficient ternary photocatalyst via anchoring nickel complex and nickel oxides onto carbon nitride for visible light driven H2 evolution

Developing earth abundant, active and stable photocatalysts for water splitting is a critical but challenging procedure for efficient conversion and storage of sustainable energy. Here, a ternary photocatalyst was rationally prepared for efficient H₂ production by covalently anchoring a nickel molecule cocatalyst (NiL) onto graphitic carbon nitride nanosheets (CN) and introducing nickel oxides (NiO_x) as hole-transport materials. The lower H₂ overpotential by NiL and the faster separation of photoinduced carriers by NiO_x nanoparticles account for the efficient H₂ generation of CN without the help of noble metals. Eventually, the prepared NiL/NiO_x/CN catalyst exhibited excellent performance for H₂ evolution (289 μmol g^?1 h^?1) in TEOA solution under visible light irradiation, which is superior to 3NiL/CN (161 μmol g^?1 h^?1) and CN (Null). Furthermore, a possible mechanism of photocatalytic H₂ production for NiL/NiO_x/CN is proposed based on a series of electrochemical measurements. The noble-metal-free photocatalyst developed in this work will pave a new way to synthesize low-cost multicomponent photocatalysts for solar conversion.