This paper demonstrates how significant improvement in frequency response and directivity of a loudspeaker may be obtained by optimizing the local properties of the materials for the diaphragm and surround. Performance is investigated as the considered frequency range and off-axis requirements are progressively expanded. The results are generated by optimizing the values and layout of stiffness, mass, and damping of both the speaker diaphragm and surround. This is accomplished using a density and gradient-based optimization technique in conjunction with a fully coupled finite element model of the loudspeaker and the surrounding acoustic domain. The targeted frequency range is from 600 Hz up to 10 kHz and the range for the directivity is from 0° to 30°. The results show that a completely flat on-axis response is achievable even for very broad frequency ranges and that a reasonably flat response over a wide directivity can be obtained as well. The results presented in this research assume that complete design and production freedom are available.
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http://dx.doi.org/10.1121/10.0005731 | DOI Listing |
J Infect Dev Ctries
December 2024
Students' Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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View Article and Find Full Text PDFIntroduction: China implemented a dynamic zero-COVID strategy to curb viral transmission in response to the coronavirus disease 2019 (COVID-19) pandemic. This strategy was designed to inhibit mutation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19. This study explores the dynamics of viral evolution under stringent non-pharmaceutical interventions (NPIs) through real-world observations.
View Article and Find Full Text PDFBMC Public Health
January 2025
School of Public Health, Southeast University, Nanjing. 87 Dingjiaqiao Road, Nanjing, China.
Background: Triglyceride-glucose (TyG) index was regarded as a cost-efficient and reliable clinical surrogate marker for insulin resistance (IR), which was significantly correlated with cardiovascular disease (CVD). However, the TyG index and incident CVD in non-diabetic hypertension patients remains uncertain. The aim of study was to explore the impact of TyG index level and variability on risk of CVD among non-diabetic hypertension patients.
View Article and Find Full Text PDFSci Rep
January 2025
Laboratory of Pharmacology, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.
Recently, exposure to sounds with ultrasound (US) components has been shown to modulate brain activity. However, the effects of US on emotional states remain poorly understood. We previously demonstrated that the olfactory bulbectomized (OBX) rat depression model is suitable for examining the effects of audible sounds on emotionality.
View Article and Find Full Text PDFSci Rep
January 2025
Division of Medical Oncology, Marmara University School of Medicine, Istanbul, Turkey.
Management of melanoma has changed significantly with the discovery of targeted therapies and immune checkpoint inhibitors (ICI). Our aim in the study is to determine which treatment alternatives, specifically dabrafenib plus trametinib and ICIs, are effective in adjuvant therapy and which treatment is effective as first-line metastatic therapy. This retrospective, multicenter study included 120 patients diagnosed with stage IIIB-IIID melanoma receiving both adjuvant and first-line metastatic treatment between 2007 and 2023.
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