State-of-the-art high power Yb-doped large mode area fibers have been developed to a performance level able to reach the so-called mode instability threshold. In this contribution we will discuss the experimental results regarding the temporal evolution (build up and decay) of this effect to come closer to a comprehensive understanding of its driving mechanisms. Our investigations prove that the relevant time scale for build up and decay of mode instability is in the millisecond range and thus deliver experimental evidence of underlying thermal effects. To the best of our knowledge these are the first systematic, time resolved investigations on that topic.
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http://dx.doi.org/10.1364/OE.20.013274 | DOI Listing |
Shanghai Kou Qiang Yi Xue
October 2024
Shaoxing Stomatological Hospital. Shaoxing 312000, Zhejiang Province, China. E-mail:
Purpose: To explore a more effective comprehensive prevention and treatment model for children's oral health by constructing a health network platform that integrates medical information evaluation, interaction, monitoring, and prevention with oral health management as the core.
Methods: The database of Shaoxing Children's Oral Health Management Network Platform was established. The oral health survey and information entry of 7 042 second-grade children in primary school in Yuecheng District from 2021 to 2022 were conducted.
Int J Legal Med
December 2024
Department of Medical Biology, Section Clinical Anatomy and Embryology, AmsterdamUMC, Location Academic Medical Centre, Meibergdreef 9, Amsterdam, AZ, 1105, The Netherlands.
Forensic taphonomy is the study of postmortem changes of human remains for the purpose of answering legal investigative questions. Many variables can affect the pattern and rate of decomposition of remains, posing challenges for taphonomic studies and estimation of the postmortem interval. Given the gap in knowledge regarding the suitability of using frozen remains to extrapolate conclusions to fresh material, investigating the effects of freeze-thaw cycles followed by burial on human remains is vital for forensic practice and taphonomic research.
View Article and Find Full Text PDFSensors (Basel)
November 2024
School of Transportation Engineering, East China Jiaotong University, Nanchang 330013, China.
In long-span bridges and high-rise buildings, closely spaced modes are commonly observed, which greatly increases the challenge of identifying modal parameters. Hilbert-Huang transform (HHT), a widely used method for modal parameter identification, first applies empirical mode decomposition (EMD) to decompose the acquired response and then uses the Hilbert transform (HT) to identify the modal parameters. However, the problem is that the deficiency of mode separation of EMD in HHT limits its application for structures with closely spaced modes.
View Article and Find Full Text PDFMolecules
November 2024
School of Physics, Changchun University of Science and Technology, Changchun 130022, China.
Lignin is one of the building blocks of plant cell walls, and the study of the spectral characterization of its cleavage process can help to monitor the production and reuse of straw after decay. In this paper, four theoretical model structures of lignin formed by lignin G monomers and connected by β-O-4 bonding type were optimized and calculated based on the density functional theory using the B3LYP/3-21g and B3LYP/6-311g basis sets. The results showed that the theoretical infrared spectra of lignin increased sequentially in the absorption peaks of 1500 cm blue shift and 2932 cm and 1200 cm red shift, while the latter three theoretical models showed new infrared absorption peaks of 716 cm and 823 cm due to the presence of the β-O-4 structure, which is of great value for the theoretical spectral study of organic macromolecules and also provides data support for the spectral change in lignin in the degradation of graminaceous plants.
View Article and Find Full Text PDFPeerJ Comput Sci
November 2024
School of Information and Communications Technology, Shenzhen City Polytechnic, Shenzhen, Gangdong, China.
In this paper, we propose enhancing feature reuse for fully convolutional one-stage object detection (EFR-FCOS) to aim at backbone, neck and head, which are three main components of object detection. For the backbone, we build a global attention network (GANet) using the block with global attention connections to extract prominent features and acquire global information from feature maps. For the neck, we design an aggregate feature fusion pyramid network (AFF-FPN) to fuse the information of feature maps with different receptive fields, which uses the attention module to extract aggregated features and reduce the decay of information in process of the feature fusion.
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