Search

In order to determine the characteristic flavor of Jingyang Fu brick tea, a national geographical indication product, the volatile compounds of Jingyang Fu brick tea, Anhua Fu brick tea and four other dark teas were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) in this study. The results showed that in total 154 compounds were identified by GC-IMS and HS-SPME-GC-MS, and the flavor composition of Jingyang Fu brick tea was clearly distinguished from that of Anhua Fu-brick tea and that of the other dark teas. Totally 12 characteristic substances of Jingyang Fu brick tea were obtained by comparative analysis with the other dark tea, seven of which were validated by GC-IMS, including 1-octen-3-one, n-hexanol, guaiacol, β-pinene, methyl butyrate, n-propanol and 2-heptanone, and the remaining five were characterized by HS-SPME-GC-MS based on aroma activity values, including hexanal, decanal, (E,E)-3,5-octadien-2-one, methyl salicylate and α-viologenone. The identification of characteristic flavor substances can provide a theoretical basis for the identification, origin tracing and processing optimization of Jingyang Fu brick tea.

Nano‐heterointerface engineering has been demonstrated to influence interfacial polarization by expanding the interface surface area and constructing a built‐in electric field (BEF), thus regulating electromagnetic (EM) wave absorption. However, the dielectric‐responsive mechanism of the BEF needs further exploration to enhance the comprehensive understanding of interfacial polarization, particularly in terms of quantifying and optimizing the BEF strength. Herein, a “1D expanded 2D structure” carbon matrix is designed, and semiconductor ZnIn2S4 (ZIS) is introduced to construct a carbon/ZIS heterostructure. The cross‐dimensional nano‐heterointerface design increases interface coupling sites by expanding the interface surface area and induces an increase in the Fermi level difference on both sides of the interface to modulate the distribution of interface charges, thereby strengthening the BEF at the interface. The synergistic effect leads to excellent EM absorption performance (minimum reflection coefficient RCmin = −67.4 dB, effective absorption bandwidth EAB = 6.0 GHz) of carbon/ZIS heterostructure. This work introduces a general modification model for enhancing interfacial polarization and inspires the development of new strategies for EM functional materials with unique electronic behaviors through heterointerface engineering. [ABSTRACT FROM AUTHOR]