Holographic images based on surface relief gratings are widely used in anti-counterfeiting labels for their high image resolution, full-color display and durability. However, traditional polymer-based holographic anti-counterfeiting labels are faced with the risk of being counterfeited due to the simple grating structures, and cannot provide further verification information except for dynamic optical effects. Moreover, in extreme environments, such as high / low temperatures, polymer-based holographic anti-counterfeiting labels may lose their encrypted information due to thermal / cold deformation. Therefore, developing one smart holographic label that is easy to read, difficult to replicate, and durable is a challenge. Herein, we propose a strategy of reconstructing quick response (QR) code on polyimide films through holographic relief gratings. And by utilizing the structural characteristics of QR code and multiplexing technology, we have achieved the integration of multiple authentication information access entrances without crosstalk at the same location. The applicability and superiority of switchable holographic QR codes that combine anti-counterfeiting and information traceability in encryption applications are discussed. This strategy for integrating encryption information based on surface relief grating provides an effective alternative for the manufacture of temperature-tolerant polymer-based smart holographic anti-counterfeiting labels.
Yue Liu,Junjie Liu,Ji Xiao,Jing Ye,Lixu Guo,Caiqing Yan
Carbonaceous aerosol, including organic carbon (OC) and elemental carbon (EC), has significant influence on human health, air quality and climate change. Accurate measurement of carbonaceous aerosol is essential to reduce the uncertainty of radiative forcing estimation and source apportionment. The accurate separation of OC and EC is controversial due to the charring of OC. Therefore, the development of reference materials (RM) for the validation of OC/EC separation is an important basis for further study. Previous RMs were mainly based on ambient air sampling, which could not provide traceability of OC and EC concentration. To develop traceable RMs with known OC/EC contents, our study applied an improved aerosol generation and mixing technique, providing uniform deposition of particles on quartz filters. To generate OC aerosol with similar pyrolytic property of ambient aerosol, both water soluble organic carbon (WSOC) and water insoluble organic carbon (WIOC) were used, and amorphous carbon was selected for EC surrogate. The RMs were analyzed using different protocols. The homogeneity within the filter was validated, reaching below 2 %. The long-term stability of RMs has been validated with RSD ranged from 1.7–3.2 %. Good correlation was observed between nominal concentration of RMs with measured concentration by two protocols, while the difference of EC concentration was within 20 %. The results indicated that the newly developed RMs were acceptable for the calibration of OC and EC, which could improve the accuracy of carbonaceous aerosol measurement. Moreover, the laboratory-generated EC-RMs could be suitable for the calibration of equivalent BC concentration by Aethalometers.
The efficiently extraction and accurately quantify of β-carotene and its metabolites are crucial for authenticity and traceability in goat milk. Nevertheless, its reliability can be largely improved. In this study, meticulously designed native ESI-MS, fluorescence spectroscopy and molecular docking in combination with cold-induced acetonitrile aqueous two-phase separation system weaken the interaction between β-lactoglobulin and β-carotene metabolites and realized the efficiently extraction. Furthermore, established non-targeted quantitative metabolomics with optimal ion source and variable data-independent acquisition minimized the matrix effects and potential ion suppression. Validated atmospheric pressure chemical ionization-ultra high performance liquid chromatography-Orbitrap method showed that β-carotene as distinctive biomarker in cow milk, and retinol, retinaldehyde, retinoic acid and abscisic acid in goat milk. Collectively, the proposed method is a powerful tool to detect cow adulteration risks in goat milk samples and provides valuable information for availability on authenticity of goat milk.
危险品化学品经营许可证（带存储）