In application, laser power is modulated prior to harmonic generation to a large part. Consequently modulation characteristics are influenced as a result of the non-linearity of harmonic generation. Within this paper, straight-forward approaches to calculate modulation key parameters (rise time, fall time, bandwidth and contrast ratio) of an acousto-optical modulator prior to harmonic generation stage are presented. The results will be compared to experimental data for third harmonic generation (THG) of a 1064 nm fs-laser which is power-modulated by a TeO2-AOM prior to THG. In the latter case, rise time and fall time are significantly reduced to approximately 66% after THG both in experimental and analytical study.
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http://dx.doi.org/10.1364/OE.20.019168 | DOI Listing |
Sci Rep
January 2025
Department of Electrical Engineering, College of Engineering, King Khalid University, P.O. Box 394, Abha, 61421, KSA, Saudi Arabia.
In wind energy generation systems, ensuring high energy quality is critical but is often compromised due to the limited performance and durability of conventional regulators. To address this, this work presents a novel controller for managing the machine-side inverter of a single-rotor large wind turbine system using an induction machine-type generator. The proposed controller is designed using proportional, integral, and derivative error-based mechanisms, which fundamentally differ from traditional proportional-integral (PI) regulators.
View Article and Find Full Text PDFLife (Basel)
December 2024
Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital, Massachusetts General Hospital, Harvard Medical School, 1575 Cambridge Street, Cambridge, MA 02115, USA.
Background: This study aimed to explore the potential associations between voice metrics of patients with PD and their motor symptoms.
Methods: Motor and vocal data including the Unified Parkinson's Disease Rating Scale part III (UPDRS-III), Harmonic-Noise Ratio (HNR), jitter, shimmer, and smoothed cepstral peak prominence (CPPS) were analyzed through exploratory correlations followed by univariate linear regression analyses. We employed these four voice metrics as independent variables and the total and sub-scores of the UPDRS-III as dependent variables.
Materials (Basel)
January 2025
Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong.
This paper investigates the effects of particle morphology (PM) and particle size distribution (PSD) on the micro-macro mechanical behaviours of granular soils through a novel X-ray micro-computed tomography (μCT)-based discrete element method (DEM) technique. This technique contains the grain-scale property extraction by the X-ray μCT, DEM parameter calibration by the one-to-one mapping technique, and the massive derivative DEM simulations. In total, 25 DEM samples were generated with a consideration of six PSDs and four PMs.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
School of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China.
In practical engineering applications, the vibration is often generated in various directions and can be harmful to the engineering equipment. Thus, it is necessary to develop vibration isolators that can reduce vibration in multiple directions. In this paper, we propose a planar two-dimensional vibration isolator based on compliant mechanisms.
View Article and Find Full Text PDFSci Rep
January 2025
Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Pudong New Area, Shanghai, 201203, China.
A major histologic feature of cirrhosis is the loss of liver architecture with collapse of tissue and vascular changes per unit. We developed qVessel to quantify the arterial density (AD) in liver biopsies with chronic disease of varied etiology and stage. 46 needle liver biopsy samples with chronic hepatitis B (CHB), 48 with primary biliary cholangitis (PBC) and 43 with metabolic dysfunction-associated steatotic liver disease (MASLD) were collected at the Shuguang Hospital.
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