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The origin of the high-frequency shoulder (HFS) observed above the longitudinal optical (LO) peak around 230 cm in the Raman spectra of CdSe quantum dots (QDs) has been the subject of intense debate. We use state-of-the-art density functional theory applied to small CdSe QDs with various realistic surface passivations and find an intense Raman signal around 230 cm, which corresponds to a stretching vibration of a defective 2-fold coordinated Se atom. We interpret this signal as being the origin of the HFS. Since the signal disappears in fully passivated and defect-free (magic size cluster) structures, it can be used as a fingerprint to distinguish defective from nondefective structures.
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http://dx.doi.org/10.1021/acs.jpclett.4c02335 | DOI Listing |
Int J Gen Med
September 2025
Department of Dermatology, Hangzhou Third People's Hospital, Hangzhou Third Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, People's Republic of China.
Background: Nodular hidradenoma (NH) is a rare benign adnexal tumor originating from sweat glands, often misdiagnosed due to nonspecific clinical manifestations. Ultrasonography (US) plays a critical role in the diagnosis of skin tumors, yet systematic descriptions of its sonographic features remain limited.
Objective: This study aims to investigate the very-high-frequency (VHF) characteristics of eccrine nodular hidradenoma (ENH) and establish key imaging criteria to differentiate it from other cutaneous/subcutaneous lesions.
Front Vet Sci
August 2025
Faculty of Veterinary Medicine, Lusófona University-Lisbon University Centre, Lisbon, Portugal.
Introduction: is a well-recognized etiologic agent of upper respiratory tract disease in tortoises. Although frequently reported in both captive and wild populations across Europe, its occurrence in Portugal had not been previously documented. This study aimed to investigate the presence of in apparently healthy captive tortoises in mainland Portugal and to evaluate potential host- and management-related factors associated with infection.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, carrer dels Til·lers, Cerdanyola del Vallès, 08193 Barcelona, Spain.
The functional properties of nanocrystals can be finely tuned through controlled morphology and size. However, this can be challenging for metastable nanostructures that require harsh synthesis conditions, such as high temperatures. Here, we present a method for preparing large ε-FeO nanorods that are not affected by magnetic relaxation.
View Article and Find Full Text PDFNat Commun
August 2025
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V., Berlin, Germany.
Controlling the symmetry of optical and mechanical waves is pivotal to their full exploitation in technological applications and topology-linked fundamental physics experiments. Leveraging on the control of orbital angular momentum, we introduce here a device forming acoustic vortices which can impart an orbital angular momentum modulation at super-high-frequency on reflected light beams. Originated by shape-engineering of a single-contact bulk acoustic wave resonator, acoustic vortices are generated in a wide band of frequencies around 4 GHz with topological charge ranging from 1 to beyond 13 tunable by the device geometry and/or excitation frequency.
View Article and Find Full Text PDFMaterials (Basel)
August 2025
School of Transportation, Southeast University, Nanjing 210018, China.
Permittivity measurements of concrete materials benefit from the application of high-frequency electromagnetic waves (HF-EMWs), but they still face the problem of being aleatory and exhibit epistemic uncertainty, originating from multi-phase heterogeneous materials and the limited knowledge of HF-EMW propagation. This limitation restricts the precision of non-destructive testing. This study proposes an evidential regression deep network for conducting permittivity measurements with uncertainty quantification.
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