健康城市系统双重属性:保障性与促进性

健康城市系统理论研究是指导健康城市规划与建设的重要依据。我国健康城市理论研究目前存在缺乏系统性、共识性分析框架、属性研究滞后等问题。研究阐明了健康城市的五大系统—健康政治、产业、文化、科技及空间系统的内涵及它们之间相对独立又相互关联的关系,重点解读了健康城市的双重属性—保障性与促进性,提出基于政策、产业、文化、科技及空间形态等层面的促进手段。     

Engineered nanomaterials-based sensing systems for assessing the freshness of meat and aquatic products: A state-of-the-art review

Meat and aquatic products are susceptible to spoilage during distribution, transportation, and storage, increasing the urgency of freshness evaluation. Engineered nanomaterials (ENMs) typically with the diameter in the range of 1–100 nm exhibit fascinating physicochemical properties. ENMs-based sensing systems have received extensive attention for food freshness assessment due to the advantages of being fast, simple, and sensitive. This review focuses on summarizing the recent application of ENMs-based sensing systems for food freshness detection. First, chemical indicators related to the freshness of meat and aquatic products are described. Then, how to apply the ENMs including noble metal nanomaterials, metal oxide nanomaterials, carbon nanomaterials, and metal–organic frameworks for the construction of different sensing systems were described. Besides, the recent advance in ENMs-based colorimetric, fluorescent, electrochemical, and surface-enhanced Raman spectroscopy sensing systems for assessing the freshness of meat and aquatic products were outlined. Finally, the challenges and future research perspectives for the application of ENMs-based sensing systems were discussed. The ENMs-based sensing systems have been demonstrated as effective tools for freshness evaluation. The sensing performance of ENMs employed in different sensing systems depends on their composition, size, shape, and stability of nanoparticles. For the real application of ENMs in food industries, the risks and regulatory issues associated with nanomaterials need to be further considered. With the continuous development of nanomaterials and sensing devices, the ENMs-based sensors are expected to be applied in-field for rapid detection of the freshness of meat and aquatic products in the future.     

Homogeneous Intercalation Chemistry and Ultralow Strain of 1T’’’ MoS2 for Stable Potassium Storage

Intercalation anodes usually exhibit better cyclability than conversion and alloying anodes for lithium or sodium storage due to the robust layered structure. However, for larger-sized potassium accommodation, these intercalation anodes usually undergo huge layer expansion and structural distortion, triggering severe capacity fading. Herein, the novel 1T’’’ MoS₂ is revealed the intercalation anode for stable K⁺ storage, in which metallic Mo─Mo bonds and puckered S layers accelerate the charge transfer and homogeneous K⁺ insertion. Moreover, the ultralow strain (3.5%) induced by the non-detachable potassium ions pillar sustains the layered structure. Consequently, 1T’’’ MoS₂ achieves a reversible capacity of 125 mA h g⁻¹ at 0.2 C and keeps nearly 100% capacity retention at 1 C over 500 cycles. In situ characterizations and density functional theory simulations reveal the in-depth intercalation reaction accompanied by the MoS₂ phase transformation between 1T’’’ and 1T’ during cycling. Furthermore, a 1T’’’ MoS₂//MCMB K-dual ion battery displays a superior cycling lifespan with 98% capacity retention over 250 cycles. This study provides a new intercalation anode and contribute to the electrode design for stable potassium ion storage.