The techniques and methods employed in the spectroscopic characterization of gases, liquids, and solids in the terahertz frequency range are reviewed. Terahertz time-domain spectroscopy is applied to address a broadband frequency range between 100 GHz and 5 THz with a sub-10 GHz frequency resolution. The unique spectral absorption features measured can be efficiently used in material identification and sensing. Possibilities and limitations of fundamental and industrial applications are discussed.
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http://dx.doi.org/10.1002/cphc.201100158 | DOI Listing |
J Phys Condens Matter
January 2025
ECE Department, University of Wisconsin at Madison, 1415 Engineering Dr, Rm 3442, Madison, WI 53706, USA, Madison, Wisconsin, 53706, UNITED STATES.
Two-dimensional (2D) van der Waals materials are shaping the landscape of next-generation devices, offering significant technological value thanks to their unique, tunable, and layer-dependent electronic and optoelectronic properties. Time-domain spectroscopic techniques at terahertz (THz) frequencies offer noninvasive, contact-free methods for characterizing the dynamics of carriers in 2D materials. They also pave the path toward the applications of 2D materials in detection, imaging, manufacturing, and communication within the increasingly important THz frequency range.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
December 2024
Key Laboratory of Modern Preparation of TCM,Ministry of Education, Jiangxi University of Chinese Medicine Nanchang 330004, China National Key Laboratory of Creation of Modern Chinese Medicine with Classical Formulas Nanchang 330004, China.
In recent years, with the increasing societal focus on drug quality and safety, quality issues have become a major challenge faced by the pharmaceutical industry, directly impacting consumer health and market trust. By combining multispectral imaging technology with machine learning, it is possible to achieve rapid, non-destructive, and precise detection of traditional Chinese medicine(TCM) preparations, thereby revolutionizing traditional detection methods and developing more convenient and automated solutions. This paper provides a comprehensive review of the current applications of rapid, non-destructive detection techniques based on machine learning algorithms in the field of TCM preparations.
View Article and Find Full Text PDFACS Nano
January 2025
School of Information Science and Technology and Department of Optical Science and Engineering and Key Laboratory of Micro and Nano Photonic Structures (MOE), Fudan University, Shanghai 200433, China.
The formation of large polarons resulting from the Fröhlich coupling of photogenerated carriers with the polarized crystal lattice is considered crucial in shaping the outstanding optoelectronic properties in hybrid organic-inorganic perovskite crystals. Until now, the initial polaron dynamics after photoexcitation have remained elusive in the hybrid perovskite system. Here, based on the terahertz time-domain spectroscopy and optical-pump terahertz probe, we access the nature of interplay between photoexcited unbound charge carriers and optical phonons in MAPbBr within the initial 5 ps after excitation and have demonstrated the simultaneous existence of both electron- and hole-polarons, together with the photogenerated carrier dynamic process.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Intelligent Equipment Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China. Electronic address:
Gender identification of chick embryos at the early stages of incubation is of significant importance to poultry industry. Existing studies showed reproductive hormone concentrations are associated with gender of chick embryos. Accurate detection of reproductive hormone concentration can assist in gender identification.
View Article and Find Full Text PDFInt J Pharm
December 2024
Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK. Electronic address:
Pharmaceutical tablets are routinely film-coated to improve appearance, reduce medication errors and enhance storage stability. Terahertz pulsed imaging (TPI) can be utilised to study the liquid penetration into the porous tablet matrix in real time. Using polymer-coated flat-faced tablets with anhydrous lactose or mannitol, we show that when the tablet matrix contains anhydrous material, the anhydrous form transforms to the solid-state hydrate form in the tablet core while the immediate release coating dissolves.
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