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Sichuan shai vinegar (SSV) is an acidic condiment with a long history and unique flavor. Aging is an important production process that determines the unique flavor of shai vinegar. This study compared the differences in physicochemical properties, volatile flavor, and non-volatile flavor substances between the constant temperature aging and natural aging methods of SSV Cupei. The results showed that the total acid and amino acid nitrogen content in naturally aged vinegar was higher than that in constant temperature aged vinegar. Furthermore, 20 different volatile flavor substances and 65 different non-volatile flavor substances were obtained after 21 and 25 days of constant temperature aging and 1, 3, and 5 years of natural aging SSV samples. This indicates that the temperature environment during natural aging was more moderate, allowing acidic compounds to form and stably exist in the aging environment. Correlation analysis further demonstrated that there were more differentiated non-volatile substances significantly related to the Maillard reaction under constant temperature aging condition and related to antioxidant activity under natural aging condition. The results of this study provide a comprehensive understanding of the characteristics and applications of the two aging methods of SSV and guide strategy for factories in the selection of aging methods.
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http://dx.doi.org/10.1016/j.foodres.2024.115080 | DOI Listing |
Nat Commun
September 2025
Research Center Future Energy Materials and Systems of the Research Alliance Ruhr, Bochum, Germany.
The theoretical maximum critical temperature (T) for conventional superconductors at ambient pressure remains a fundamental question in condensed matter physics. Through analysis of electron-phonon calculations for over 20,000 metals, we critically examine this question. We find that while hydride metals can exhibit maximum phonon frequencies of more than 5000 K, the crucial logarithmic average frequency rarely exceeds 1800 K.
View Article and Find Full Text PDFJ Colloid Interface Sci
September 2025
State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address:
Polyimide (PI) faces significant challenges in highly integrated and high-frequency electronic devices due to its inherently low thermal conductivity and relatively high dielectric constant (D). In this study, topologically micro-crosslinked PI films were synthesized by incorporating highly conjugated multi-amino polydiacetylene (MAPDA) into a fluorinated PI matrix. The unique alkene-alkyne alternating conjugated structure of MAPDA, combined with the strong electron-withdrawing trifluoromethyl groups in the matrix, promotes charge redistribution and reduces the dipole moment and polarizability.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
ShanghaiTech University, School of Physical Science and Technology, Shanghai 201210, China.
We report direct spectroscopic evidence of correlation-driven Mott states in layered Nb_{3}Cl_{8} through combining scanning tunneling microscopy (STM) and dynamical mean-field theory. The Hubbard bands persist down to monolayer, providing the definitive evidence for the Mottness in Nb_{3}Cl_{8}. While the size of the Mott gap remains almost constant across all layers, a striking layer-parity-dependent oscillation emerges in the local density of states (LDOS) between even (n=2, 4, 6) and odd layers (n=1, 3, 5), which arises from the dimerization and correlation modulation of the obstructed atomic states, respectively.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India.
This work presents a gas-phase experimental study on the reduction of NO (nitrogen dioxide) to HONO (nitrous acid) by two atmospherically significant volatile organic compounds (VOCs), namely, glycolaldehyde (Gla) and hydroxyacetone (HAc), under a simulated tropospheric condition. FTIR spectroscopic probing reveals that HONO is the only gaseous reduced product of NO in each reaction. The measured data indicate that the reactions in both cases occur in a 2 : 1 stoichiometry with respect to NO and Gla/HAc.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
September 2025
Departamento de Física Aplicada - Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr Moliner 50, 46100 Burjassot, Valencia Spain.
The effects of pressure on the crystal structure of scheelite-type perrhenates were studied using synchrotron powder X-ray diffraction and density-functional theory. At ambient conditions, the studied materials AgReO, KReO, and RbReO, exhibit a tetragonal scheelite-type crystal structure described by space group 4/. Under compression, a transition from scheelite-to-M'-fergusonite (space group 2/) was observed at 1.
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