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[Display omitted] • A non-noble-metal based novel SERS substrate-porous carbon film/WO 3-x nanosheets was developed; • Detection limit of 10-7 M with the Raman enhancement factor of 106 was achieved on the optical substrate. • A deep leaning method was used to accurately analyze the Raman spectra of flavonoids of quercetin, 3-hydroxyflavone and flavone. • Quercetin can be accurately detected by the fully convolutional network, and lowest detectable concentration of 10-5 M was achieved. The Surface-enhanced Raman scattering (SERS) is an attractive optical detecting method with high sensitivity and detectivity, however challenges on large-area signal uniformity and complex spectra analysis methods always retards its wide application. Herein, a highly sensitive and uniform SERS detection strategy supported by porous carbon film/WO 3-x nanosheets (PorC/WO 3-x) based noble-metal-free SERS substrate and deep learning algorithm are reported. Experimentally, the PorC/WO 3-x substrate was prepared by high-temperature annealing the PorC/WO 3 films under the argon atmosphere. The defect density of the WO 3 was controlled by tuning the reducing reaction time during the annealing process. The SERS performance was evaluated by using R6G as the Raman reporter, it showed that the SERS intensity obtained on the substrate with the optimal annealing time of 3 h was about 8 times as high as that obtained on the PorC/WO 3 substrate without annealing treatment. And detection limit of 10-7 M and Raman enhancement factor of 106 could be achieved. Moreover, the above optimal SERS substrate was utilized to detect flavonoids of quercetin, 3-hydroxyflavone and flavone, and a deep learning algorithms was incorporated to identify the quercetin. It revealed that quercetin can be accurately detected within the above flavonoids, and lowest detectable concentration of 10-5 M can be achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid SERS substrate constructed by porous carbons film and silver nanoparticle (PCs/Ag NPs) was developed; • The PCs/Ag NPs SERS substrate was used for imatinib (IMT) detection in bio-environment; • Excellent detectivity and sensitivity was obtained when detecting the IMT in blood plasma and whole blood. Surface enhanced Raman scattering (SERS) is a rapid and non-destructive spectral detection technique, and has been widely implemented on trace-level molecule detection. In this work, a hybrid SERS substrate constructed by porous carbon film and silver nanoparticles (PCs/Ag NPs) was developed and then used for imatinib (IMT) detection in bio-environment. The PCs/Ag NPs was prepared by direct carbonizing the gelatin-AgNO 3 film in the air atmosphere, and an enhancement factor (EF) of 106 was achieved with R6G as the Raman reporter. Hereafter, this SERS substrate was used as the label-free sensing platform to detect the IMT in the serum, and the experimental results indicate that the substrate is conducive to eliminating the interference from the complex biological molecules in the serum, and the characteristic Raman peaks belonging to IMT (10-4 M) are accurately resolved. Furthermore, the SERS substrate was used to trace the IMT in the whole blood, the trace of ultra-low concertation of IMT is rapidly discovered without any pretreatment. Thus, this work finally suggests that the proposed sensing platform provides a rapid and reliable method for IMT detection in the bio-environment and offers a potential for its application in therapeutic drug monitoring. [ABSTRACT FROM AUTHOR]

Rural residential areas are an extensive dispersion with localized concentrations, and the area of land utilization per capita is large in Dazhu village in Hechuan of Chongqing. Inefficient utilization of rural residential areas is an adverse process all over China during the urban-rural transitional period, especially in traditional agricultural areas. The space reconstruction of a rural residential area could be a breakthrough in the rational utilization of land resources, advancing new countryside construction, restructuring village space, and promoting urban-rural integration and development. This paper used the symbiotic theory to establish a rural residential restructuring symbiotic system. The system included rural residential areas as a symbiotic unit, and the policy environment and the village-domain environment as symbiotic environment. Due to the mutual functional differences of symbiotic units, village spatial reconstruction should consider a mutually beneficial symbiotic relationship between the units, namely the mutualism mode. The research analyzed a rural residential restructuring symbiotic system, and made clear the restructuring principles and procedure needed to build the space reconstruction strategy of a rural settlement. The thesis selected the demonstration village of the whole village advancement—Dazhu village in Hechuan of Chongqing as the object of empirical study. It built three kinds of functional groups—productivity-oriented, service-oriented, and living-oriented groups, a space representation of which was already presented in the village, and formed the layout of 'one axis and three groups' at the the village scale. The results showed that: first, adopting the rural residential restructuring symbiotic system analysis accords with the reality of Dazhu village to restructure village space. It further showed that the symbiotic theory has strong applicability to space reconstruction of a rural settlement. Secondly, the results of the empirical study showed that the space reconstruction of a rural settlement, which is based on the symbiotic strategy, can both ensure the inter-operability of a rural settlement and respect the principal position of farmers. It realizes 'shared resources, co-constructed environment' and exploits environmental advantages in the village domain. It can also improve the utilization efficiency of rural residential areas. Through the study of the demonstration village, the paper provides a scientific basis for formulating village space reconstruction and a new approach to the whole village advancement in a hilly area and the beautiful village construction. Due to the fact that the factors which influence rural residential restructuring are very complex, the regional social, economic, and environmental development strategies and resource endowment conditions which are expected to be considered comprehensively, need to be studied further. Different types of household willingness and future livelihoods also require deeper study. [ABSTRACT FROM AUTHOR]

We propose a facile strategy to synchronously achieve surface reconstruction and grain boundary healing by using 1,3-propylene diamine (PDA) post-treatment on CsPbI 3 film. Consequently, the inverted PDA-based CsPbI 3 device yields a champion PCE of 20.02% with significantly improved long-term storage stability and operational stability. [Display omitted] • The PDA can break the soft CsPbI 3 structure in the shallow surface. • PDA passivates defect sites on the surface and grain boundaries of CsPbI 3 films. • The inverted CsPbI 3 device with PDA achieves a champion efficiency of 20.02%. • The long-term storage and operational stability are significantly improved. Cesium lead iodide (CsPbI 3) perovskite has gained considerable attentions due to its unique photoelectric properties. However, numerous defects are inevitably existed on the surface and grain boundaries (GBs) of CsPbI 3 resulting from the rapid crystallization and growth progress. Herein, different from the traditional ammonium salt treatment mechanism, we propose a facile strategy to synchronously achieve surface reconstruction and grain boundary healing by using 1,3-propylene diamine (PDA) post-treatment on CsPbI 3 film. It is discovered that the PDA with suitable concentration can preferentially invade the defect sites of surface and GBs of CsPbI 3 film, thereby break the soft perovskite structure in the shallow surface. With further low temperature annealing treatment, the broken CsPbI 3 surface would undergo rapid secondary crystal growth to acquire smoother and blurred morphology with reduced GBs and pinholes, primarily derived from the strong interaction between the highly active amino groups of liquid PDA and Pb of perovskite. Meanwhile, the residual PDA molecules mainly anchor at the surface and GBs, and thus connect neighboring perovskite grains, coordinate uncoordinated sites to effectively passivate defects, and also resist the external invasions. Consequently, the inverted PDA-based CsPbI 3 device yields a champion PCE of 20.02% with significantly improved long-term storage stability and operational stability. [ABSTRACT FROM AUTHOR]