The effect of transverse mode instability is a limitation for the power scaling of fiber laser systems, that can originate due to heat caused by stimulated Raman scattering. In this contribution, we experimentally investigate the threshold of transverse mode instability caused by stimulated Raman scattering in a passive fiber. Both, the Stokes seed power and the fiber length of a core-pumped Raman fiber amplifier are varied to systematically study this effect. Mode resolved measurements reveal that the threshold occurs at approximately the same Stokes output power for all tested configurations, independent of the total Raman conversion efficiency. These results increase the understanding of this type of mode instability and show which parameters are important for a further power scaling of high-power Raman fiber amplifiers.
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Sci Rep
December 2024
China Construction Eighth Engineering Division Rail Transit Construction Co., Ltd, Nanjing, 210018, Jiangsu, China.
The existing calculation method for the surrounding rock pressure of shallow buried bias tunnel fails to account for the impact of the progressive failure characteristics of the surrounding rock and slope creep, thereby neglecting the additional pressure arising from slope creep. Therefore, the progressive instability failure mode of the surrounding rock of shallow buried bias tunnel was obtained by numerical simulation. Based on this, the theoretical analysis model of the additional pressure of shallow buried bias tunnel was established, and the calculation formula of the additional pressure was derived.
View Article and Find Full Text PDFTransverse mode instability (TMI) significantly limits the power scaling of ytterbium-doped fiber lasers. In this Letter, what we believe to be a novel TMI mitigation strategy is proposed and demonstrated in a bidirectional output fiber laser. On the basis of the continuous wave (CW) pump, integrating a quasi-continuous wave (QCW) pump can effectively improve the TMI threshold of the system.
View Article and Find Full Text PDFJ Orthop Traumatol
December 2024
Sapienza Universitiy, Rome, Italy.
Introduction: The plantar plate, also called the plantar ligament, is a fibrocartilaginous structure found in the metatarsophalangeal (MTP) and interphalangeal (IP) joints. Our study aimed to evaluate the role of magnetic resonance imaging (MRI) performed with the patient in the standard position or with joint hyperextension (the "stress test", ST) in the study of plantar plate (PP) disease that involves metatarsophalangeal joints.
Materials And Methods: All patients underwent forefoot MRI (Atroscan C, Esaote, Genoa, Italy), operating at 0.
J Pharm Sci
December 2024
Department of Industrial and Molecular Pharmaceutics, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA. Electronic address:
Current RNA lipid nanoparticle (LNP) based products are typically liquid formulations that require ultra-cold storage temperatures for stability. To address this limitation, recent efforts have focused on enhancing stability and enabling room temperature storage by converting these formulations into solid forms through drying processes such as lyophilization, spray drying, and spray-freeze drying. Nevertheless, the drying process itself can influence the stability of RNA/LNP formulations.
View Article and Find Full Text PDFLab Chip
December 2024
College of Engineering and Applied Sciences, Nanjing University, Jiangsu 210093, China.
Acoustic waves provide an effective method for object manipulation in microfluidics, often requiring high-frequency ultrasound in the megahertz range when directly handling microsized objects, which can be costly. Micro-air-bubbles in water offer a solution toward low-cost technologies using low-frequency acoustic waves. Owing to their high compressibility and low elastic modulus, these bubbles can exhibit significant expansion and contraction in response to even kilohertz acoustic waves, leading to resonances with frequencies determined and tuned by air-bubble size.
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