This study used scale model experiments to investigate the insertion losses of balconies on a building façade in the presence of ground reflections. The experiments measured both A-weighted broad- and narrowband insertion loss spectra. The underlying wave interactions/interferences and their couplings with and without reflections from the balcony ceilings were also examined in detail, and these findings were related to the dimensions and elevations of the balconies. The findings indicate that the ground and ceiling reflections and their interferences with the direct sound play very important roles in shaping the frequency characteristics of the insertion losses. Strong sound attenuation can be attained with a carefully designed geometry and acoustical properties of the balcony and the balcony ceiling.
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http://dx.doi.org/10.1121/1.4883379 | DOI Listing |
We propose and demonstrate integrated photonic crystal (PhC) beam splitters based on X-cut thin film lithium niobate (TFLN). Its working principle is based on bandgap guidance and total reflection in the PhC slab. We designed two structures: one features a triangular lattice, while the other exhibits a tetragonal lattice.
View Article and Find Full Text PDFMatrix-vector multiplications (MVMs) are essential for a wide range of applications, particularly in modern machine learning and quantum computing. In photonics, there is growing interest in developing architectures capable of performing linear operations with high speed, low latency, and minimal loss. Traditional interferometric photonic architectures, such as the Clements design, have been extensively used for MVM operations.
View Article and Find Full Text PDFDigital nanophotonic devices have achieved both an ultra-compact footprint and flexibly designed functions, which hold great potential for ultradense photonic integrated circuits. However, the performance deteriorates rapidly when the size of pixels varies due to fabrication errors. In this work, we propose an inverse design method called robust adjoint method to design fabrication-tolerant digital nanophotonic devices.
View Article and Find Full Text PDFEJNMMI Phys
January 2025
Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Solna, Sweden.
Background: System calibration is essential for accurate SPECT/CT dosimetry. However, count losses due to dead time and pulse pileup may cause calibration errors, in particular for I, where high count rates may be encountered. Calibration at low count rates should also be avoided to minimise detrimental effects from e.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
State Key Laboratory of Radio Frequency Heterogeneous Integration, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Institute for Advanced Study in Nuclear Energy & Safety, Interdisciplinary Center of High Magnetic Field Physics of Shenzhen University, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
With the rapid advancement of information technology, the data demands in transmission rates, processing speed, and storage capacity have been increasing significantly. However, silicon electro-optic modulators, characterized by their weak electro-optic effect, struggle to balance modulation efficiency and bandwidth. To overcome this limitation, we propose an electro-optic modulator based on an all-fiber micro-ring resonator and a p-Si/n-ITO heterojunction, achieving high modulation efficiency and large bandwidth.
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